/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*! \file */
#include <config.h>
#include <ctype.h>
#include <inttypes.h>
#include <stdbool.h>
#include <isc/counter.h>
#include <isc/log.h>
#include <isc/platform.h>
#include <isc/print.h>
#include <isc/string.h>
#include <isc/random.h>
#include <isc/siphash.h>
#include <isc/socket.h>
#include <isc/stats.h>
#include <isc/task.h>
#include <isc/timer.h>
#include <isc/util.h>
#include <dns/acl.h>
#include <dns/adb.h>
#include <dns/badcache.h>
#include <dns/cache.h>
#include <dns/db.h>
#include <dns/dispatch.h>
#include <dns/dnstap.h>
#include <dns/ds.h>
#include <dns/edns.h>
#include <dns/events.h>
#include <dns/fixedname.h>
#include <dns/forward.h>
#include <dns/keytable.h>
#include <dns/log.h>
#include <dns/message.h>
#include <dns/ncache.h>
#include <dns/nsec.h>
#include <dns/nsec3.h>
#include <dns/opcode.h>
#include <dns/peer.h>
#include <dns/rbt.h>
#include <dns/rcode.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdatastruct.h>
#include <dns/rdatatype.h>
#include <dns/resolver.h>
#include <dns/result.h>
#include <dns/rootns.h>
#include <dns/stats.h>
#include <dns/tsig.h>
#include <dns/validator.h>
#ifdef WANT_QUERYTRACE
#define RTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"res %p: %s", res, (m))
#define RRTRACE(r, m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"res %p: %s", (r), (m))
#define FCTXTRACE(m) \
isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"fctx %p(%s): %s", \
fctx, fctx->info, (m))
#define FCTXTRACE2(m1, m2) \
isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"fctx %p(%s): %s %s", \
fctx, fctx->info, (m1), (m2))
#define FCTXTRACE3(m, res) \
isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"fctx %p(%s): [result: %s] %s", \
fctx, fctx->info, \
isc_result_totext(res), (m))
#define FCTXTRACE4(m1, m2, res) \
isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"fctx %p(%s): [result: %s] %s %s", \
fctx, fctx->info, \
isc_result_totext(res), (m1), (m2))
#define FCTXTRACE5(m1, m2, v) \
isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"fctx %p(%s): %s %s%u", \
fctx, fctx->info, (m1), (m2), (v))
#define FTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"fetch %p (fctx %p(%s)): %s", \
fetch, fetch->private, \
fetch->private->info, (m))
#define QTRACE(m) isc_log_write(dns_lctx, \
DNS_LOGCATEGORY_RESOLVER, \
DNS_LOGMODULE_RESOLVER, \
ISC_LOG_DEBUG(3), \
"resquery %p (fctx %p(%s)): %s", \
query, query->fctx, \
query->fctx->info, (m))
#else
#define RTRACE(m) do { UNUSED(m); } while (0)
#define RRTRACE(r, m) do { UNUSED(r); UNUSED(m); } while (0)
#define FCTXTRACE(m) do { UNUSED(m); } while (0)
#define FCTXTRACE2(m1, m2) do { UNUSED(m1); UNUSED(m2); } while (0)
#define FCTXTRACE3(m1, res) do { UNUSED(m1); UNUSED(res); } while (0)
#define FCTXTRACE4(m1, m2, res) \
do { UNUSED(m1); UNUSED(m2); UNUSED(res); } while (0)
#define FCTXTRACE5(m1, m2, v) \
do { UNUSED(m1); UNUSED(m2); UNUSED(v); } while (0)
#define FTRACE(m) do { UNUSED(m); } while (0)
#define QTRACE(m) do { UNUSED(m); } while (0)
#endif /* WANT_QUERYTRACE */
#define US_PER_SEC 1000000U
/*
* The maximum time we will wait for a single query.
*/
#define MAX_SINGLE_QUERY_TIMEOUT 9U
#define MAX_SINGLE_QUERY_TIMEOUT_US (MAX_SINGLE_QUERY_TIMEOUT*US_PER_SEC)
/*
* We need to allow a individual query time to complete / timeout.
*/
#define MINIMUM_QUERY_TIMEOUT (MAX_SINGLE_QUERY_TIMEOUT + 1U)
/* The default time in seconds for the whole query to live. */
#ifndef DEFAULT_QUERY_TIMEOUT
#define DEFAULT_QUERY_TIMEOUT MINIMUM_QUERY_TIMEOUT
#endif
/* The maximum time in seconds for the whole query to live. */
#ifndef MAXIMUM_QUERY_TIMEOUT
#define MAXIMUM_QUERY_TIMEOUT 30
#endif
/* The default maximum number of recursions to follow before giving up. */
#ifndef DEFAULT_RECURSION_DEPTH
#define DEFAULT_RECURSION_DEPTH 7
#endif
/* The default maximum number of iterative queries to allow before giving up. */
#ifndef DEFAULT_MAX_QUERIES
#define DEFAULT_MAX_QUERIES 100
#endif /* ifndef DEFAULT_MAX_QUERIES */
/*
* After NS_FAIL_LIMIT attempts to fetch a name server address,
* if the number of addresses in the NS RRset exceeds NS_RR_LIMIT,
* stop trying to fetch, in order to avoid wasting resources.
*/
#define NS_FAIL_LIMIT 4
#define NS_RR_LIMIT 5
/* Number of hash buckets for zone counters */
#ifndef RES_DOMAIN_BUCKETS
#define RES_DOMAIN_BUCKETS 523
#endif
#define RES_NOBUCKET 0xffffffff
/*%
* Maximum EDNS0 input packet size.
*/
#define RECV_BUFFER_SIZE 4096 /* XXXRTH Constant. */
/*%
* This defines the maximum number of timeouts we will permit before we
* disable EDNS0 on the query.
*/
#define MAX_EDNS0_TIMEOUTS 3
#define DNS_RESOLVER_BADCACHESIZE 1021
#define DNS_RESOLVER_BADCACHETTL(fctx) \
(((fctx)->res->lame_ttl > 30 ) ? (fctx)->res->lame_ttl : 30)
typedef struct fetchctx fetchctx_t;
typedef struct query {
/* Locked by task event serialization. */
unsigned int magic;
fetchctx_t * fctx;
dns_message_t * rmessage;
isc_mem_t * mctx;
dns_dispatchmgr_t * dispatchmgr;
dns_dispatch_t * dispatch;
bool exclusivesocket;
dns_adbaddrinfo_t * addrinfo;
isc_socket_t * tcpsocket;
isc_time_t start;
dns_messageid_t id;
dns_dispentry_t * dispentry;
ISC_LINK(struct query) link;
isc_buffer_t buffer;
isc_buffer_t *tsig;
dns_tsigkey_t *tsigkey;
isc_socketevent_t sendevent;
isc_dscp_t dscp;
int ednsversion;
unsigned int options;
unsigned int attributes;
unsigned int sends;
unsigned int connects;
unsigned int udpsize;
unsigned char data[512];
} resquery_t;
struct tried {
isc_sockaddr_t addr;
unsigned int count;
ISC_LINK(struct tried) link;
};
#define QUERY_MAGIC ISC_MAGIC('Q', '!', '!', '!')
#define VALID_QUERY(query) ISC_MAGIC_VALID(query, QUERY_MAGIC)
#define RESQUERY_ATTR_CANCELED 0x02
#define RESQUERY_CONNECTING(q) ((q)->connects > 0)
#define RESQUERY_CANCELED(q) (((q)->attributes & \
RESQUERY_ATTR_CANCELED) != 0)
#define RESQUERY_SENDING(q) ((q)->sends > 0)
typedef enum {
fetchstate_init = 0, /*%< Start event has not run yet. */
fetchstate_active,
fetchstate_done /*%< FETCHDONE events posted. */
} fetchstate;
typedef enum {
badns_unreachable = 0,
badns_response,
badns_validation,
badns_forwarder,
} badnstype_t;
struct fetchctx {
/*% Not locked. */
unsigned int magic;
dns_resolver_t * res;
dns_name_t name;
dns_rdatatype_t type;
unsigned int options;
unsigned int bucketnum;
unsigned int dbucketnum;
char * info;
isc_mem_t * mctx;
/*% Locked by appropriate bucket lock. */
fetchstate state;
bool want_shutdown;
bool cloned;
bool spilled;
bool shuttingdown;
unsigned int references;
isc_event_t control_event;
ISC_LINK(struct fetchctx) link;
ISC_LIST(dns_fetchevent_t) events;
/*% Locked by task event serialization. */
dns_name_t domain;
dns_rdataset_t nameservers;
unsigned int attributes;
isc_timer_t * timer;
isc_time_t expires;
isc_interval_t interval;
dns_message_t * qmessage;
ISC_LIST(resquery_t) queries;
dns_adbfindlist_t finds;
dns_adbfind_t * find;
dns_adbfindlist_t altfinds;
dns_adbfind_t * altfind;
dns_adbaddrinfolist_t forwaddrs;
dns_adbaddrinfolist_t altaddrs;
dns_forwarderlist_t forwarders;
dns_fwdpolicy_t fwdpolicy;
isc_sockaddrlist_t bad;
ISC_LIST(struct tried) edns;
ISC_LIST(struct tried) edns512;
isc_sockaddrlist_t bad_edns;
dns_validator_t * validator;
ISC_LIST(dns_validator_t) validators;
dns_db_t * cache;
dns_adb_t * adb;
bool ns_ttl_ok;
uint32_t ns_ttl;
isc_counter_t * qc;
/*%
* The number of events we're waiting for.
*/
unsigned int pending; /* Bucket lock. */
/*%
* The number of times we've "restarted" the current
* nameserver set. This acts as a failsafe to prevent
* us from pounding constantly on a particular set of
* servers that, for whatever reason, are not giving
* us useful responses, but are responding in such a
* way that they are not marked "bad".
*/
unsigned int restarts;
/*%
* The number of timeouts that have occurred since we
* last successfully received a response packet. This
* is used for EDNS0 black hole detection.
*/
unsigned int timeouts;
/*%
* Look aside state for DS lookups.
*/
dns_name_t nsname;
dns_fetch_t * nsfetch;
dns_rdataset_t nsrrset;
/*%
* Number of queries that reference this context.
*/
unsigned int nqueries; /* Bucket lock. */
/*%
* The reason to print when logging a successful
* response to a query.
*/
const char * reason;
/*%
* Random numbers to use for mixing up server addresses.
*/
uint32_t rand_buf;
uint32_t rand_bits;
/*%
* Fetch-local statistics for detailed logging.
*/
isc_result_t result; /*%< fetch result */
isc_result_t vresult; /*%< validation result */
int exitline;
isc_time_t start;
uint64_t duration;
bool logged;
unsigned int querysent;
unsigned int referrals;
unsigned int lamecount;
unsigned int quotacount;
unsigned int neterr;
unsigned int badresp;
unsigned int adberr;
unsigned int findfail;
unsigned int valfail;
bool timeout;
dns_adbaddrinfo_t *addrinfo;
unsigned int depth;
char clientstr[ISC_SOCKADDR_FORMATSIZE];
};
#define FCTX_MAGIC ISC_MAGIC('F', '!', '!', '!')
#define VALID_FCTX(fctx) ISC_MAGIC_VALID(fctx, FCTX_MAGIC)
#define FCTX_ATTR_HAVEANSWER 0x0001
#define FCTX_ATTR_GLUING 0x0002
#define FCTX_ATTR_ADDRWAIT 0x0004
#define FCTX_ATTR_WANTCACHE 0x0010
#define FCTX_ATTR_WANTNCACHE 0x0020
#define FCTX_ATTR_NEEDEDNS0 0x0040
#define FCTX_ATTR_TRIEDFIND 0x0080
#define FCTX_ATTR_TRIEDALT 0x0100
#define HAVE_ANSWER(f) (((f)->attributes & FCTX_ATTR_HAVEANSWER) != \
0)
#define GLUING(f) (((f)->attributes & FCTX_ATTR_GLUING) != \
0)
#define ADDRWAIT(f) (((f)->attributes & FCTX_ATTR_ADDRWAIT) != \
0)
#define WANTCACHE(f) (((f)->attributes & FCTX_ATTR_WANTCACHE) != 0)
#define WANTNCACHE(f) (((f)->attributes & FCTX_ATTR_WANTNCACHE) != 0)
#define NEEDEDNS0(f) (((f)->attributes & FCTX_ATTR_NEEDEDNS0) != 0)
#define TRIEDFIND(f) (((f)->attributes & FCTX_ATTR_TRIEDFIND) != 0)
#define TRIEDALT(f) (((f)->attributes & FCTX_ATTR_TRIEDALT) != 0)
#define FCTX_ATTR_SET(f, x) do { (f)->attributes |= (x); } while (0)
#define FCTX_ATTR_CLR(f, x) do { (f)->attributes &= ~(x); } while (0)
typedef struct {
dns_adbaddrinfo_t * addrinfo;
fetchctx_t * fctx;
dns_message_t * rmessage;
} dns_valarg_t;
typedef struct {
fetchctx_t * fctx;
dns_message_t * rmessage;
} dns_chkarg_t;
struct dns_fetch {
unsigned int magic;
isc_mem_t * mctx;
fetchctx_t * private;
};
#define DNS_FETCH_MAGIC ISC_MAGIC('F', 't', 'c', 'h')
#define DNS_FETCH_VALID(fetch) ISC_MAGIC_VALID(fetch, DNS_FETCH_MAGIC)
typedef struct fctxbucket {
isc_task_t * task;
isc_mutex_t lock;
ISC_LIST(fetchctx_t) fctxs;
bool exiting;
isc_mem_t * mctx;
} fctxbucket_t;
typedef struct fctxcount fctxcount_t;
struct fctxcount {
dns_fixedname_t fdname;
dns_name_t *domain;
uint32_t count;
uint32_t allowed;
uint32_t dropped;
isc_stdtime_t logged;
ISC_LINK(fctxcount_t) link;
};
typedef struct zonebucket {
isc_mutex_t lock;
isc_mem_t *mctx;
ISC_LIST(fctxcount_t) list;
} zonebucket_t;
typedef struct alternate {
bool isaddress;
union {
isc_sockaddr_t addr;
struct {
dns_name_t name;
in_port_t port;
} _n;
} _u;
ISC_LINK(struct alternate) link;
} alternate_t;
struct dns_resolver {
/* Unlocked. */
unsigned int magic;
isc_mem_t * mctx;
isc_mutex_t lock;
isc_mutex_t nlock;
isc_mutex_t primelock;
isc_mutex_t spill_lock;
dns_rdataclass_t rdclass;
isc_socketmgr_t * socketmgr;
isc_timermgr_t * timermgr;
isc_taskmgr_t * taskmgr;
dns_view_t * view;
bool frozen;
unsigned int options;
dns_dispatchmgr_t * dispatchmgr;
dns_dispatchset_t * dispatches4;
bool exclusivev4;
dns_dispatchset_t * dispatches6;
isc_dscp_t querydscp4;
isc_dscp_t querydscp6;
bool exclusivev6;
unsigned int nbuckets;
fctxbucket_t * buckets;
zonebucket_t * dbuckets;
uint32_t lame_ttl;
ISC_LIST(alternate_t) alternates;
uint16_t udpsize;
#if USE_ALGLOCK
isc_rwlock_t alglock;
#endif
dns_rbt_t * algorithms;
dns_rbt_t * digests;
#if USE_MBSLOCK
isc_rwlock_t mbslock;
#endif
dns_rbt_t * mustbesecure;
unsigned int spillatmax;
unsigned int spillatmin;
isc_timer_t * spillattimer;
bool zero_no_soa_ttl;
unsigned int query_timeout;
unsigned int maxdepth;
unsigned int maxqueries;
isc_result_t quotaresp[2];
/* Locked by lock. */
unsigned int zspill; /* fetches-per-zone */
/* Locked by lock. */
unsigned int references;
bool exiting;
isc_eventlist_t whenshutdown;
unsigned int activebuckets;
bool priming;
unsigned int spillat; /* clients-per-query */
dns_badcache_t * badcache; /* Bad cache. */
/* Locked by primelock. */
dns_fetch_t * primefetch;
/* Locked by nlock. */
unsigned int nfctx;
};
#define RES_MAGIC ISC_MAGIC('R', 'e', 's', '!')
#define VALID_RESOLVER(res) ISC_MAGIC_VALID(res, RES_MAGIC)
/*%
* Private addrinfo flags. These must not conflict with DNS_FETCHOPT_NOEDNS0
* (0x008) which we also use as an addrinfo flag.
*/
#define FCTX_ADDRINFO_MARK 0x00001
#define FCTX_ADDRINFO_FORWARDER 0x01000
#define FCTX_ADDRINFO_EDNSOK 0x04000
#define FCTX_ADDRINFO_NOCOOKIE 0x08000
#define FCTX_ADDRINFO_BADCOOKIE 0x10000
#define UNMARKED(a) (((a)->flags & FCTX_ADDRINFO_MARK) \
== 0)
#define ISFORWARDER(a) (((a)->flags & \
FCTX_ADDRINFO_FORWARDER) != 0)
#define NOCOOKIE(a) (((a)->flags & \
FCTX_ADDRINFO_NOCOOKIE) != 0)
#define EDNSOK(a) (((a)->flags & \
FCTX_ADDRINFO_EDNSOK) != 0)
#define BADCOOKIE(a) (((a)->flags & \
FCTX_ADDRINFO_BADCOOKIE) != 0)
#define NONTA(o) (((o) & DNS_FETCHOPT_NONTA) != 0)
#define NXDOMAIN(r) (((r)->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0)
#define NEGATIVE(r) (((r)->attributes & DNS_RDATASETATTR_NEGATIVE) != 0)
#ifdef ENABLE_AFL
bool dns_fuzzing_resolver = false;
void dns_resolver_setfuzzing() {
dns_fuzzing_resolver = true;
}
#endif
static void destroy(dns_resolver_t *res);
static void empty_bucket(dns_resolver_t *res);
static isc_result_t resquery_send(resquery_t *query);
static void resquery_response(isc_task_t *task, isc_event_t *event);
static void resquery_connected(isc_task_t *task, isc_event_t *event);
static void fctx_try(fetchctx_t *fctx, bool retrying,
bool badcache);
static void fctx_destroy(fetchctx_t *fctx);
static bool fctx_unlink(fetchctx_t *fctx);
static isc_result_t ncache_adderesult(dns_message_t *message,
dns_db_t *cache, dns_dbnode_t *node,
dns_rdatatype_t covers,
isc_stdtime_t now, dns_ttl_t maxttl,
bool optout,
bool secure,
dns_rdataset_t *ardataset,
isc_result_t *eresultp);
static void validated(isc_task_t *task, isc_event_t *event);
static bool maybe_destroy(fetchctx_t *fctx, bool locked);
static void add_bad(fetchctx_t *fctx, dns_message_t *rmessage,
dns_adbaddrinfo_t *addrinfo, isc_result_t reason,
badnstype_t badtype);
static inline isc_result_t findnoqname(fetchctx_t *fctx,
dns_message_t *rmessage,
dns_name_t *name,
dns_rdatatype_t type,
dns_name_t **noqname);
static void fctx_increference(fetchctx_t *fctx);
static bool fctx_decreference(fetchctx_t *fctx);
/*%
* Increment resolver-related statistics counters.
*/
static inline void
inc_stats(dns_resolver_t *res, isc_statscounter_t counter) {
if (res->view->resstats != NULL)
isc_stats_increment(res->view->resstats, counter);
}
static inline void
dec_stats(dns_resolver_t *res, isc_statscounter_t counter) {
if (res->view->resstats != NULL)
isc_stats_decrement(res->view->resstats, counter);
}
static isc_result_t
valcreate(fetchctx_t *fctx, dns_message_t *rmessage,
dns_adbaddrinfo_t *addrinfo, dns_name_t *name,
dns_rdatatype_t type, dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset, unsigned int valoptions,
isc_task_t *task)
{
dns_validator_t *validator = NULL;
dns_valarg_t *valarg;
isc_result_t result;
valarg = isc_mem_get(fctx->mctx, sizeof(*valarg));
if (valarg == NULL)
return (ISC_R_NOMEMORY);
valarg->fctx = fctx;
valarg->addrinfo = addrinfo;
dns_message_attach(rmessage, &valarg->rmessage);
if (!ISC_LIST_EMPTY(fctx->validators))
valoptions |= DNS_VALIDATOR_DEFER;
else
valoptions &= ~DNS_VALIDATOR_DEFER;
result = dns_validator_create(fctx->res->view, name, type, rdataset,
sigrdataset, rmessage,
valoptions, task, validated, valarg,
&validator);
if (result == ISC_R_SUCCESS) {
inc_stats(fctx->res, dns_resstatscounter_val);
if ((valoptions & DNS_VALIDATOR_DEFER) == 0) {
INSIST(fctx->validator == NULL);
fctx->validator = validator;
}
ISC_LIST_APPEND(fctx->validators, validator, link);
} else {
dns_message_detach(&valarg->rmessage);
isc_mem_put(fctx->mctx, valarg, sizeof(*valarg));
}
return (result);
}
static bool
rrsig_fromchildzone(fetchctx_t *fctx, dns_rdataset_t *rdataset) {
dns_namereln_t namereln;
dns_rdata_rrsig_t rrsig;
dns_rdata_t rdata = DNS_RDATA_INIT;
int order;
isc_result_t result;
unsigned int labels;
for (result = dns_rdataset_first(rdataset);
result == ISC_R_SUCCESS;
result = dns_rdataset_next(rdataset)) {
dns_rdataset_current(rdataset, &rdata);
result = dns_rdata_tostruct(&rdata, &rrsig, NULL);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
namereln = dns_name_fullcompare(&rrsig.signer, &fctx->domain,
&order, &labels);
if (namereln == dns_namereln_subdomain)
return (true);
dns_rdata_reset(&rdata);
}
return (false);
}
static bool
fix_mustbedelegationornxdomain(dns_message_t *message, fetchctx_t *fctx) {
dns_name_t *name;
dns_name_t *domain = &fctx->domain;
dns_rdataset_t *rdataset;
dns_rdatatype_t type;
isc_result_t result;
bool keep_auth = false;
if (message->rcode == dns_rcode_nxdomain)
return (false);
/*
* A DS RRset can appear anywhere in a zone, even for a delegation-only
* zone. So a response to an explicit query for this type should be
* excluded from delegation-only fixup.
*
* SOA, NS, and DNSKEY can only exist at a zone apex, so a positive
* response to a query for these types can never violate the
* delegation-only assumption: if the query name is below a
* zone cut, the response should normally be a referral, which should
* be accepted; if the query name is below a zone cut but the server
* happens to have authority for the zone of the query name, the
* response is a (non-referral) answer. But this does not violate
* delegation-only because the query name must be in a different zone
* due to the "apex-only" nature of these types. Note that if the
* remote server happens to have authority for a child zone of a
* delegation-only zone, we may still incorrectly "fix" the response
* with NXDOMAIN for queries for other types. Unfortunately it's
* generally impossible to differentiate this case from violation of
* the delegation-only assumption. Once the resolver learns the
* correct zone cut, possibly via a separate query for an "apex-only"
* type, queries for other types will be resolved correctly.
*
* A query for type ANY will be accepted if it hits an exceptional
* type above in the answer section as it should be from a child
* zone.
*
* Also accept answers with RRSIG records from the child zone.
* Direct queries for RRSIG records should not be answered from
* the parent zone.
*/
if (message->counts[DNS_SECTION_ANSWER] != 0 &&
(fctx->type == dns_rdatatype_ns ||
fctx->type == dns_rdatatype_ds ||
fctx->type == dns_rdatatype_soa ||
fctx->type == dns_rdatatype_any ||
fctx->type == dns_rdatatype_rrsig ||
fctx->type == dns_rdatatype_dnskey)) {
result = dns_message_firstname(message, DNS_SECTION_ANSWER);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, DNS_SECTION_ANSWER,
&name);
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
if (!dns_name_equal(name, &fctx->name))
continue;
type = rdataset->type;
/*
* RRsig from child?
*/
if (type == dns_rdatatype_rrsig &&
rrsig_fromchildzone(fctx, rdataset))
return (false);
/*
* Direct query for apex records or DS.
*/
if (fctx->type == type &&
(type == dns_rdatatype_ds ||
type == dns_rdatatype_ns ||
type == dns_rdatatype_soa ||
type == dns_rdatatype_dnskey))
return (false);
/*
* Indirect query for apex records or DS.
*/
if (fctx->type == dns_rdatatype_any &&
(type == dns_rdatatype_ns ||
type == dns_rdatatype_ds ||
type == dns_rdatatype_soa ||
type == dns_rdatatype_dnskey))
return (false);
}
result = dns_message_nextname(message,
DNS_SECTION_ANSWER);
}
}
/*
* A NODATA response to a DS query?
*/
if (fctx->type == dns_rdatatype_ds &&
message->counts[DNS_SECTION_ANSWER] == 0)
return (false);
/* Look for referral or indication of answer from child zone? */
if (message->counts[DNS_SECTION_AUTHORITY] == 0)
goto munge;
result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
type = rdataset->type;
if (type == dns_rdatatype_soa &&
dns_name_equal(name, domain))
keep_auth = true;
if (type != dns_rdatatype_ns &&
type != dns_rdatatype_soa &&
type != dns_rdatatype_rrsig)
continue;
if (type == dns_rdatatype_rrsig) {
if (rrsig_fromchildzone(fctx, rdataset))
return (false);
else
continue;
}
/* NS or SOA records. */
if (dns_name_equal(name, domain)) {
/*
* If a query for ANY causes a negative
* response, we can be sure that this is
* an empty node. For other type of queries
* we cannot differentiate an empty node
* from a node that just doesn't have that
* type of record. We only accept the former
* case.
*/
if (message->counts[DNS_SECTION_ANSWER] == 0 &&
fctx->type == dns_rdatatype_any)
return (false);
} else if (dns_name_issubdomain(name, domain)) {
/* Referral or answer from child zone. */
return (false);
}
}
result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
}
munge:
message->rcode = dns_rcode_nxdomain;
message->counts[DNS_SECTION_ANSWER] = 0;
if (!keep_auth)
message->counts[DNS_SECTION_AUTHORITY] = 0;
message->counts[DNS_SECTION_ADDITIONAL] = 0;
return (true);
}
static inline isc_result_t
fctx_starttimer(fetchctx_t *fctx) {
/*
* Start the lifetime timer for fctx.
*
* This is also used for stopping the idle timer; in that
* case we must purge events already posted to ensure that
* no further idle events are delivered.
*/
return (isc_timer_reset(fctx->timer, isc_timertype_once,
&fctx->expires, NULL, true));
}
static inline void
fctx_stoptimer(fetchctx_t *fctx) {
isc_result_t result;
/*
* We don't return a result if resetting the timer to inactive fails
* since there's nothing to be done about it. Resetting to inactive
* should never fail anyway, since the code as currently written
* cannot fail in that case.
*/
result = isc_timer_reset(fctx->timer, isc_timertype_inactive,
NULL, NULL, true);
if (result != ISC_R_SUCCESS) {
UNEXPECTED_ERROR(__FILE__, __LINE__,
"isc_timer_reset(): %s",
isc_result_totext(result));
}
}
static inline isc_result_t
fctx_startidletimer(fetchctx_t *fctx, isc_interval_t *interval) {
/*
* Start the idle timer for fctx. The lifetime timer continues
* to be in effect.
*/
return (isc_timer_reset(fctx->timer, isc_timertype_once,
&fctx->expires, interval, false));
}
/*
* Stopping the idle timer is equivalent to calling fctx_starttimer(), but
* we use fctx_stopidletimer for readability in the code below.
*/
#define fctx_stopidletimer fctx_starttimer
static inline void
resquery_destroy(resquery_t **queryp) {
dns_resolver_t *res;
bool empty;
resquery_t *query;
fetchctx_t *fctx;
unsigned int bucket;
REQUIRE(queryp != NULL);
query = *queryp;
REQUIRE(!ISC_LINK_LINKED(query, link));
INSIST(query->tcpsocket == NULL);
fctx = query->fctx;
res = fctx->res;
bucket = fctx->bucketnum;
LOCK(&res->buckets[bucket].lock);
fctx->nqueries--;
empty = fctx_decreference(query->fctx);
UNLOCK(&res->buckets[bucket].lock);
dns_message_detach(&query->rmessage);
query->magic = 0;
isc_mem_put(query->mctx, query, sizeof(*query));
*queryp = NULL;
if (empty)
empty_bucket(res);
}
/*%
* Update EDNS statistics for a server after not getting a response to a UDP
* query sent to it.
*/
static void
update_edns_stats(resquery_t *query) {
fetchctx_t *fctx = query->fctx;
if ((query->options & DNS_FETCHOPT_TCP) != 0) {
return;
}
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
dns_adb_ednsto(fctx->adb, query->addrinfo, query->udpsize);
} else {
dns_adb_timeout(fctx->adb, query->addrinfo);
}
}
static void
fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
isc_time_t *finish, bool no_response,
bool age_untried)
{
fetchctx_t *fctx;
resquery_t *query;
unsigned int rtt, rttms;
unsigned int factor;
dns_adbfind_t *find;
dns_adbaddrinfo_t *addrinfo;
isc_socket_t *sock;
isc_stdtime_t now;
query = *queryp;
fctx = query->fctx;
FCTXTRACE("cancelquery");
REQUIRE(!RESQUERY_CANCELED(query));
query->attributes |= RESQUERY_ATTR_CANCELED;
/*
* Should we update the RTT?
*/
if (finish != NULL || no_response) {
if (finish != NULL) {
/*
* We have both the start and finish times for this
* packet, so we can compute a real RTT.
*/
rtt = (unsigned int)isc_time_microdiff(finish,
&query->start);
factor = DNS_ADB_RTTADJDEFAULT;
rttms = rtt / 1000;
if (rttms < DNS_RESOLVER_QRYRTTCLASS0) {
inc_stats(fctx->res,
dns_resstatscounter_queryrtt0);
} else if (rttms < DNS_RESOLVER_QRYRTTCLASS1) {
inc_stats(fctx->res,
dns_resstatscounter_queryrtt1);
} else if (rttms < DNS_RESOLVER_QRYRTTCLASS2) {
inc_stats(fctx->res,
dns_resstatscounter_queryrtt2);
} else if (rttms < DNS_RESOLVER_QRYRTTCLASS3) {
inc_stats(fctx->res,
dns_resstatscounter_queryrtt3);
} else if (rttms < DNS_RESOLVER_QRYRTTCLASS4) {
inc_stats(fctx->res,
dns_resstatscounter_queryrtt4);
} else {
inc_stats(fctx->res,
dns_resstatscounter_queryrtt5);
}
} else {
uint32_t value;
uint32_t mask;
update_edns_stats(query);
/*
* If "forward first;" is used and a forwarder timed
* out, do not attempt to query it again in this fetch
* context.
*/
if (fctx->fwdpolicy == dns_fwdpolicy_first &&
ISFORWARDER(query->addrinfo))
{
add_bad(fctx, query->rmessage,
query->addrinfo, ISC_R_TIMEDOUT,
badns_forwarder);
}
/*
* We don't have an RTT for this query. Maybe the
* packet was lost, or maybe this server is very
* slow. We don't know. Increase the RTT.
*/
INSIST(no_response);
isc_random_get(&value);
if (query->addrinfo->srtt > 800000)
mask = 0x3fff;
else if (query->addrinfo->srtt > 400000)
mask = 0x7fff;
else if (query->addrinfo->srtt > 200000)
mask = 0xffff;
else if (query->addrinfo->srtt > 100000)
mask = 0x1ffff;
else if (query->addrinfo->srtt > 50000)
mask = 0x3ffff;
else if (query->addrinfo->srtt > 25000)
mask = 0x7ffff;
else
mask = 0xfffff;
/*
* Don't adjust timeout on EDNS queries unless we have
* seen a EDNS response.
*/
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0 &&
!EDNSOK(query->addrinfo)) {
mask >>= 2;
}
rtt = query->addrinfo->srtt + (value & mask);
if (rtt > MAX_SINGLE_QUERY_TIMEOUT_US)
rtt = MAX_SINGLE_QUERY_TIMEOUT_US;
/*
* Replace the current RTT with our value.
*/
factor = DNS_ADB_RTTADJREPLACE;
}
dns_adb_adjustsrtt(fctx->adb, query->addrinfo, rtt, factor);
}
if ((query->options & DNS_FETCHOPT_TCP) == 0) {
/* Inform the ADB that we're ending a UDP fetch */
dns_adb_endudpfetch(fctx->adb, query->addrinfo);
}
/*
* Age RTTs of servers not tried.
*/
isc_stdtime_get(&now);
if (finish != NULL || age_untried)
for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink))
if (UNMARKED(addrinfo))
dns_adb_agesrtt(fctx->adb, addrinfo, now);
if ((finish != NULL || age_untried) && TRIEDFIND(fctx))
for (find = ISC_LIST_HEAD(fctx->finds);
find != NULL;
find = ISC_LIST_NEXT(find, publink))
for (addrinfo = ISC_LIST_HEAD(find->list);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink))
if (UNMARKED(addrinfo))
dns_adb_agesrtt(fctx->adb, addrinfo,
now);
if ((finish != NULL || age_untried) && TRIEDALT(fctx)) {
for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink))
if (UNMARKED(addrinfo))
dns_adb_agesrtt(fctx->adb, addrinfo, now);
for (find = ISC_LIST_HEAD(fctx->altfinds);
find != NULL;
find = ISC_LIST_NEXT(find, publink))
for (addrinfo = ISC_LIST_HEAD(find->list);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink))
if (UNMARKED(addrinfo))
dns_adb_agesrtt(fctx->adb, addrinfo,
now);
}
/*
* Check for any outstanding socket events. If they exist, cancel
* them and let the event handlers finish the cleanup. The resolver
* only needs to worry about managing the connect and send events;
* the dispatcher manages the recv events.
*/
if (RESQUERY_CONNECTING(query)) {
/*
* Cancel the connect.
*/
if (query->tcpsocket != NULL) {
isc_socket_cancel(query->tcpsocket, NULL,
ISC_SOCKCANCEL_CONNECT);
} else if (query->dispentry != NULL) {
INSIST(query->exclusivesocket);
sock = dns_dispatch_getentrysocket(query->dispentry);
if (sock != NULL)
isc_socket_cancel(sock, NULL,
ISC_SOCKCANCEL_CONNECT);
}
}
if (RESQUERY_SENDING(query)) {
/*
* Cancel the pending send.
*/
if (query->exclusivesocket && query->dispentry != NULL)
sock = dns_dispatch_getentrysocket(query->dispentry);
else
sock = dns_dispatch_getsocket(query->dispatch);
if (sock != NULL)
isc_socket_cancel(sock, NULL, ISC_SOCKCANCEL_SEND);
}
if (query->dispentry != NULL)
dns_dispatch_removeresponse(&query->dispentry, deventp);
ISC_LIST_UNLINK(fctx->queries, query, link);
if (query->tsig != NULL)
isc_buffer_free(&query->tsig);
if (query->tsigkey != NULL)
dns_tsigkey_detach(&query->tsigkey);
if (query->dispatch != NULL)
dns_dispatch_detach(&query->dispatch);
if (! (RESQUERY_CONNECTING(query) || RESQUERY_SENDING(query)))
/*
* It's safe to destroy the query now.
*/
resquery_destroy(&query);
}
static void
fctx_cancelqueries(fetchctx_t *fctx, bool no_response,
bool age_untried)
{
resquery_t *query, *next_query;
FCTXTRACE("cancelqueries");
for (query = ISC_LIST_HEAD(fctx->queries);
query != NULL;
query = next_query) {
next_query = ISC_LIST_NEXT(query, link);
fctx_cancelquery(&query, NULL, NULL, no_response,
age_untried);
}
}
static void
fctx_cleanupfinds(fetchctx_t *fctx) {
dns_adbfind_t *find, *next_find;
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
for (find = ISC_LIST_HEAD(fctx->finds);
find != NULL;
find = next_find)
{
next_find = ISC_LIST_NEXT(find, publink);
ISC_LIST_UNLINK(fctx->finds, find, publink);
dns_adb_destroyfind(&find);
}
fctx->find = NULL;
}
static void
fctx_cleanupaltfinds(fetchctx_t *fctx) {
dns_adbfind_t *find, *next_find;
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
for (find = ISC_LIST_HEAD(fctx->altfinds);
find != NULL;
find = next_find)
{
next_find = ISC_LIST_NEXT(find, publink);
ISC_LIST_UNLINK(fctx->altfinds, find, publink);
dns_adb_destroyfind(&find);
}
fctx->altfind = NULL;
}
static void
fctx_cleanupforwaddrs(fetchctx_t *fctx) {
dns_adbaddrinfo_t *addr, *next_addr;
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
for (addr = ISC_LIST_HEAD(fctx->forwaddrs);
addr != NULL;
addr = next_addr)
{
next_addr = ISC_LIST_NEXT(addr, publink);
ISC_LIST_UNLINK(fctx->forwaddrs, addr, publink);
dns_adb_freeaddrinfo(fctx->adb, &addr);
}
}
static void
fctx_cleanupaltaddrs(fetchctx_t *fctx) {
dns_adbaddrinfo_t *addr, *next_addr;
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
for (addr = ISC_LIST_HEAD(fctx->altaddrs);
addr != NULL;
addr = next_addr)
{
next_addr = ISC_LIST_NEXT(addr, publink);
ISC_LIST_UNLINK(fctx->altaddrs, addr, publink);
dns_adb_freeaddrinfo(fctx->adb, &addr);
}
}
static inline void
fctx_stopqueries(fetchctx_t *fctx, bool no_response,
bool age_untried)
{
FCTXTRACE("stopqueries");
fctx_cancelqueries(fctx, no_response, age_untried);
fctx_stoptimer(fctx);
}
static inline void
fctx_cleanupall(fetchctx_t *fctx) {
fctx_cleanupfinds(fctx);
fctx_cleanupaltfinds(fctx);
fctx_cleanupforwaddrs(fctx);
fctx_cleanupaltaddrs(fctx);
}
static void
fcount_logspill(fetchctx_t *fctx, fctxcount_t *counter) {
char dbuf[DNS_NAME_FORMATSIZE];
isc_stdtime_t now;
if (! isc_log_wouldlog(dns_lctx, ISC_LOG_INFO))
return;
isc_stdtime_get(&now);
if (counter->logged > now - 60)
return;
dns_name_format(&fctx->domain, dbuf, sizeof(dbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_SPILL,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"too many simultaneous fetches for %s "
"(allowed %d spilled %d)",
dbuf, counter->allowed, counter->dropped);
counter->logged = now;
}
static isc_result_t
fcount_incr(fetchctx_t *fctx, bool force) {
isc_result_t result = ISC_R_SUCCESS;
zonebucket_t *dbucket;
fctxcount_t *counter;
unsigned int bucketnum;
REQUIRE(fctx != NULL);
REQUIRE(fctx->res != NULL);
INSIST(fctx->dbucketnum == RES_NOBUCKET);
bucketnum = dns_name_fullhash(&fctx->domain, false)
% RES_DOMAIN_BUCKETS;
dbucket = &fctx->res->dbuckets[bucketnum];
LOCK(&dbucket->lock);
for (counter = ISC_LIST_HEAD(dbucket->list);
counter != NULL;
counter = ISC_LIST_NEXT(counter, link))
{
if (dns_name_equal(counter->domain, &fctx->domain))
break;
}
if (counter == NULL) {
counter = isc_mem_get(dbucket->mctx, sizeof(fctxcount_t));
if (counter == NULL)
result = ISC_R_NOMEMORY;
else {
ISC_LINK_INIT(counter, link);
counter->count = 1;
counter->logged = 0;
counter->allowed = 1;
counter->dropped = 0;
counter->domain =
dns_fixedname_initname(&counter->fdname);
dns_name_copy(&fctx->domain, counter->domain, NULL);
ISC_LIST_APPEND(dbucket->list, counter, link);
}
} else {
unsigned int spill;
LOCK(&fctx->res->spill_lock);
spill = fctx->res->zspill;
UNLOCK(&fctx->res->spill_lock);
if (!force && spill != 0 && counter->count >= spill) {
counter->dropped++;
fcount_logspill(fctx, counter);
result = ISC_R_QUOTA;
} else {
counter->count++;
counter->allowed++;
}
}
UNLOCK(&dbucket->lock);
if (result == ISC_R_SUCCESS)
fctx->dbucketnum = bucketnum;
return (result);
}
static void
fcount_decr(fetchctx_t *fctx) {
zonebucket_t *dbucket;
fctxcount_t *counter;
REQUIRE(fctx != NULL);
if (fctx->dbucketnum == RES_NOBUCKET)
return;
dbucket = &fctx->res->dbuckets[fctx->dbucketnum];
LOCK(&dbucket->lock);
for (counter = ISC_LIST_HEAD(dbucket->list);
counter != NULL;
counter = ISC_LIST_NEXT(counter, link))
{
if (dns_name_equal(counter->domain, &fctx->domain))
break;
}
if (counter != NULL) {
INSIST(counter->count != 0);
counter->count--;
fctx->dbucketnum = RES_NOBUCKET;
if (counter->count == 0) {
ISC_LIST_UNLINK(dbucket->list, counter, link);
isc_mem_put(dbucket->mctx, counter, sizeof(*counter));
}
}
UNLOCK(&dbucket->lock);
}
static inline void
fctx_sendevents(fetchctx_t *fctx, isc_result_t result, int line) {
dns_fetchevent_t *event, *next_event;
isc_task_t *task;
unsigned int count = 0;
isc_interval_t i;
bool logit = false;
isc_time_t now;
unsigned int old_spillat;
unsigned int new_spillat = 0; /* initialized to silence
compiler warnings */
/*
* Caller must be holding the appropriate bucket lock.
*/
REQUIRE(fctx->state == fetchstate_done);
FCTXTRACE("sendevents");
/*
* Keep some record of fetch result for logging later (if required).
*/
fctx->result = result;
fctx->exitline = line;
TIME_NOW(&now);
fctx->duration = isc_time_microdiff(&now, &fctx->start);
for (event = ISC_LIST_HEAD(fctx->events);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, ev_link);
ISC_LIST_UNLINK(fctx->events, event, ev_link);
task = event->ev_sender;
event->ev_sender = fctx;
event->vresult = fctx->vresult;
if (!HAVE_ANSWER(fctx))
event->result = result;
INSIST(event->result != ISC_R_SUCCESS ||
dns_rdataset_isassociated(event->rdataset) ||
fctx->type == dns_rdatatype_any ||
fctx->type == dns_rdatatype_rrsig ||
fctx->type == dns_rdatatype_sig);
/*
* Negative results must be indicated in event->result.
*/
if (dns_rdataset_isassociated(event->rdataset) &&
NEGATIVE(event->rdataset)) {
INSIST(event->result == DNS_R_NCACHENXDOMAIN ||
event->result == DNS_R_NCACHENXRRSET);
}
isc_task_sendanddetach(&task, ISC_EVENT_PTR(&event));
count++;
}
LOCK(&fctx->res->spill_lock);
if ((fctx->attributes & FCTX_ATTR_HAVEANSWER) != 0 &&
fctx->spilled &&
(count < fctx->res->spillatmax || fctx->res->spillatmax == 0)) {
if (count == fctx->res->spillat && !fctx->res->exiting) {
old_spillat = fctx->res->spillat;
fctx->res->spillat += 5;
if (fctx->res->spillat > fctx->res->spillatmax &&
fctx->res->spillatmax != 0)
fctx->res->spillat = fctx->res->spillatmax;
new_spillat = fctx->res->spillat;
if (new_spillat != old_spillat) {
logit = true;
}
isc_interval_set(&i, 20 * 60, 0);
result = isc_timer_reset(fctx->res->spillattimer,
isc_timertype_ticker, NULL,
&i, true);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
}
if (logit)
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
"clients-per-query increased to %u",
new_spillat);
}
UNLOCK(&fctx->res->spill_lock);
}
static inline void
log_edns(fetchctx_t *fctx) {
char domainbuf[DNS_NAME_FORMATSIZE];
if (fctx->reason == NULL)
return;
/*
* We do not know if fctx->domain is the actual domain the record
* lives in or a parent domain so we have a '?' after it.
*/
dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_EDNS_DISABLED,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"success resolving '%s' (in '%s'?) after %s",
fctx->info, domainbuf, fctx->reason);
fctx->reason = NULL;
}
static void
fctx_done(fetchctx_t *fctx, isc_result_t result, int line) {
dns_resolver_t *res;
bool no_response = false;
bool age_untried = false;
REQUIRE(line >= 0);
FCTXTRACE("done");
res = fctx->res;
if (result == ISC_R_SUCCESS) {
/*%
* Log any deferred EDNS timeout messages.
*/
log_edns(fctx);
no_response = true;
} else if (result == ISC_R_TIMEDOUT)
age_untried = true;
fctx->reason = NULL;
fctx_stopqueries(fctx, no_response, age_untried);
LOCK(&res->buckets[fctx->bucketnum].lock);
fctx->state = fetchstate_done;
FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT);
fctx_sendevents(fctx, result, line);
UNLOCK(&res->buckets[fctx->bucketnum].lock);
}
static void
process_sendevent(resquery_t *query, isc_event_t *event) {
isc_socketevent_t *sevent = (isc_socketevent_t *)event;
bool destroy_query = false;
bool retry = false;
isc_result_t result;
fetchctx_t *fctx;
fctx = query->fctx;
if (RESQUERY_CANCELED(query)) {
if (query->sends == 0 && query->connects == 0) {
/*
* This query was canceled while the
* isc_socket_sendto/connect() was in progress.
*/
if (query->tcpsocket != NULL)
isc_socket_detach(&query->tcpsocket);
destroy_query = true;
}
} else {
switch (sevent->result) {
case ISC_R_SUCCESS:
break;
case ISC_R_HOSTUNREACH:
case ISC_R_NETUNREACH:
case ISC_R_NOPERM:
case ISC_R_ADDRNOTAVAIL:
case ISC_R_CONNREFUSED:
FCTXTRACE3("query canceled in sendevent(): "
"no route to host; no response",
sevent->result);
/*
* No route to remote.
*/
add_bad(fctx, query->rmessage, query->addrinfo,
sevent->result,
badns_unreachable);
fctx_cancelquery(&query, NULL, NULL, true,
false);
retry = true;
break;
default:
FCTXTRACE3("query canceled in sendevent() due to "
"unexpected event result; responding",
sevent->result);
fctx_cancelquery(&query, NULL, NULL, false,
false);
break;
}
}
if (event->ev_type == ISC_SOCKEVENT_CONNECT)
isc_event_free(&event);
if (retry) {
/*
* Behave as if the idle timer has expired. For TCP
* this may not actually reflect the latest timer.
*/
FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT);
result = fctx_stopidletimer(fctx);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result, __LINE__);
else
fctx_try(fctx, true, false);
}
if (destroy_query)
resquery_destroy(&query);
}
static void
resquery_udpconnected(isc_task_t *task, isc_event_t *event) {
resquery_t *query = event->ev_arg;
REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
QTRACE("udpconnected");
UNUSED(task);
INSIST(RESQUERY_CONNECTING(query));
query->connects--;
process_sendevent(query, event);
}
static void
resquery_senddone(isc_task_t *task, isc_event_t *event) {
resquery_t *query = event->ev_arg;
REQUIRE(event->ev_type == ISC_SOCKEVENT_SENDDONE);
QTRACE("senddone");
/*
* XXXRTH
*
* Currently we don't wait for the senddone event before retrying
* a query. This means that if we get really behind, we may end
* up doing extra work!
*/
UNUSED(task);
INSIST(RESQUERY_SENDING(query));
query->sends--;
process_sendevent(query, event);
}
static inline isc_result_t
fctx_addopt(dns_message_t *message, unsigned int version,
uint16_t udpsize, dns_ednsopt_t *ednsopts, size_t count)
{
dns_rdataset_t *rdataset = NULL;
isc_result_t result;
result = dns_message_buildopt(message, &rdataset, version, udpsize,
DNS_MESSAGEEXTFLAG_DO, ednsopts, count);
if (result != ISC_R_SUCCESS)
return (result);
return (dns_message_setopt(message, rdataset));
}
static inline void
fctx_setretryinterval(fetchctx_t *fctx, unsigned int rtt) {
unsigned int seconds;
unsigned int us;
/*
* We retry every .8 seconds the first two times through the address
* list, and then we do exponential back-off.
*/
if (fctx->restarts < 3)
us = 800000;
else
us = (800000 << (fctx->restarts - 2));
/*
* Add a fudge factor to the expected rtt based on the current
* estimate.
*/
if (rtt < 50000)
rtt += 50000;
else if (rtt < 100000)
rtt += 100000;
else
rtt += 200000;
/*
* Always wait for at least the expected rtt.
*/
if (us < rtt)
us = rtt;
/*
* But don't ever wait for more than 10 seconds.
*/
if (us > MAX_SINGLE_QUERY_TIMEOUT_US)
us = MAX_SINGLE_QUERY_TIMEOUT_US;
seconds = us / US_PER_SEC;
us -= seconds * US_PER_SEC;
isc_interval_set(&fctx->interval, seconds, us * 1000);
}
static isc_result_t
fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
unsigned int options)
{
dns_resolver_t *res;
isc_task_t *task;
isc_result_t result;
resquery_t *query;
isc_sockaddr_t addr;
bool have_addr = false;
unsigned int srtt;
isc_dscp_t dscp = -1;
unsigned int bucketnum;
FCTXTRACE("query");
res = fctx->res;
task = res->buckets[fctx->bucketnum].task;
srtt = addrinfo->srtt;
/*
* Allow an additional second for the kernel to resend the SYN (or
* SYN without ECN in the case of stupid firewalls blocking ECN
* negotiation) over the current RTT estimate.
*/
if ((options & DNS_FETCHOPT_TCP) != 0) {
srtt += 1000000;
}
/*
* A forwarder needs to make multiple queries. Give it at least
* a second to do these in.
*/
if (ISFORWARDER(addrinfo) && srtt < 1000000)
srtt = 1000000;
fctx_setretryinterval(fctx, srtt);
result = fctx_startidletimer(fctx, &fctx->interval);
if (result != ISC_R_SUCCESS)
return (result);
INSIST(ISC_LIST_EMPTY(fctx->validators));
query = isc_mem_get(fctx->mctx, sizeof(*query));
if (query == NULL) {
result = ISC_R_NOMEMORY;
goto stop_idle_timer;
}
query->rmessage = NULL;
result = dns_message_create(fctx->mctx, DNS_MESSAGE_INTENTPARSE,
&query->rmessage);
if (result != ISC_R_SUCCESS) {
goto cleanup_query;
}
query->mctx = fctx->mctx;
query->options = options;
query->attributes = 0;
query->sends = 0;
query->connects = 0;
query->dscp = addrinfo->dscp;
query->udpsize = 0;
/*
* Note that the caller MUST guarantee that 'addrinfo' will remain
* valid until this query is canceled.
*/
query->addrinfo = addrinfo;
TIME_NOW(&query->start);
/*
* If this is a TCP query, then we need to make a socket and
* a dispatch for it here. Otherwise we use the resolver's
* shared dispatch.
*/
query->dispatchmgr = res->dispatchmgr;
query->dispatch = NULL;
query->exclusivesocket = false;
query->tcpsocket = NULL;
if (res->view->peers != NULL) {
dns_peer_t *peer = NULL;
isc_netaddr_t dstip;
bool usetcp = false;
isc_netaddr_fromsockaddr(&dstip, &addrinfo->sockaddr);
result = dns_peerlist_peerbyaddr(res->view->peers,
&dstip, &peer);
if (result == ISC_R_SUCCESS) {
result = dns_peer_getquerysource(peer, &addr);
if (result == ISC_R_SUCCESS)
have_addr = true;
result = dns_peer_getquerydscp(peer, &dscp);
if (result == ISC_R_SUCCESS)
query->dscp = dscp;
result = dns_peer_getforcetcp(peer, &usetcp);
if (result == ISC_R_SUCCESS && usetcp)
query->options |= DNS_FETCHOPT_TCP;
}
}
dscp = -1;
if ((query->options & DNS_FETCHOPT_TCP) != 0) {
int pf;
pf = isc_sockaddr_pf(&addrinfo->sockaddr);
if (!have_addr) {
switch (pf) {
case PF_INET:
result = dns_dispatch_getlocaladdress(
res->dispatches4->dispatches[0],
&addr);
dscp = dns_resolver_getquerydscp4(fctx->res);
break;
case PF_INET6:
result = dns_dispatch_getlocaladdress(
res->dispatches6->dispatches[0],
&addr);
dscp = dns_resolver_getquerydscp6(fctx->res);
break;
default:
result = ISC_R_NOTIMPLEMENTED;
break;
}
if (result != ISC_R_SUCCESS)
goto cleanup_rmessage;
}
isc_sockaddr_setport(&addr, 0);
if (query->dscp == -1)
query->dscp = dscp;
result = isc_socket_create(res->socketmgr, pf,
isc_sockettype_tcp,
&query->tcpsocket);
if (result != ISC_R_SUCCESS)
goto cleanup_rmessage;
#ifndef BROKEN_TCP_BIND_BEFORE_CONNECT
result = isc_socket_bind(query->tcpsocket, &addr, 0);
if (result != ISC_R_SUCCESS)
goto cleanup_socket;
#endif
/*
* A dispatch will be created once the connect succeeds.
*/
} else {
if (have_addr) {
unsigned int attrs, attrmask;
attrs = DNS_DISPATCHATTR_UDP;
switch (isc_sockaddr_pf(&addr)) {
case AF_INET:
attrs |= DNS_DISPATCHATTR_IPV4;
dscp = dns_resolver_getquerydscp4(fctx->res);
break;
case AF_INET6:
attrs |= DNS_DISPATCHATTR_IPV6;
dscp = dns_resolver_getquerydscp6(fctx->res);
break;
default:
result = ISC_R_NOTIMPLEMENTED;
goto cleanup_query;
}
attrmask = DNS_DISPATCHATTR_UDP;
attrmask |= DNS_DISPATCHATTR_TCP;
attrmask |= DNS_DISPATCHATTR_IPV4;
attrmask |= DNS_DISPATCHATTR_IPV6;
result = dns_dispatch_getudp(res->dispatchmgr,
res->socketmgr,
res->taskmgr, &addr,
4096, 20000, 32768, 16411,
16433, attrs, attrmask,
&query->dispatch);
if (result != ISC_R_SUCCESS)
goto cleanup_query;
} else {
switch (isc_sockaddr_pf(&addrinfo->sockaddr)) {
case PF_INET:
dns_dispatch_attach(
dns_resolver_dispatchv4(res),
&query->dispatch);
query->exclusivesocket = res->exclusivev4;
dscp = dns_resolver_getquerydscp4(fctx->res);
break;
case PF_INET6:
dns_dispatch_attach(
dns_resolver_dispatchv6(res),
&query->dispatch);
query->exclusivesocket = res->exclusivev6;
dscp = dns_resolver_getquerydscp6(fctx->res);
break;
default:
result = ISC_R_NOTIMPLEMENTED;
goto cleanup_query;
}
}
if (query->dscp == -1)
query->dscp = dscp;
/*
* We should always have a valid dispatcher here. If we
* don't support a protocol family, then its dispatcher
* will be NULL, but we shouldn't be finding addresses for
* protocol types we don't support, so the dispatcher
* we found should never be NULL.
*/
INSIST(query->dispatch != NULL);
}
query->dispentry = NULL;
query->fctx = fctx; /* reference added by caller */
query->tsig = NULL;
query->tsigkey = NULL;
ISC_LINK_INIT(query, link);
query->magic = QUERY_MAGIC;
if ((query->options & DNS_FETCHOPT_TCP) != 0) {
/*
* Connect to the remote server.
*
* XXXRTH Should we attach to the socket?
*/
if (query->dscp != -1)
isc_socket_dscp(query->tcpsocket, query->dscp);
result = isc_socket_connect(query->tcpsocket,
&addrinfo->sockaddr, task,
resquery_connected, query);
if (result != ISC_R_SUCCESS)
goto cleanup_socket;
query->connects++;
QTRACE("connecting via TCP");
} else {
if (dns_adbentry_overquota(fctx->adb, addrinfo->entry))
goto cleanup_dispatch;
/* Inform the ADB that we're starting a UDP fetch */
dns_adb_beginudpfetch(fctx->adb, addrinfo);
result = resquery_send(query);
if (result != ISC_R_SUCCESS)
goto cleanup_dispatch;
}
fctx->querysent++;
ISC_LIST_APPEND(fctx->queries, query, link);
bucketnum = fctx->bucketnum;
LOCK(&res->buckets[bucketnum].lock);
fctx->nqueries++;
UNLOCK(&res->buckets[bucketnum].lock);
if (isc_sockaddr_pf(&addrinfo->sockaddr) == PF_INET)
inc_stats(res, dns_resstatscounter_queryv4);
else
inc_stats(res, dns_resstatscounter_queryv6);
if (res->view->resquerystats != NULL)
dns_rdatatypestats_increment(res->view->resquerystats,
fctx->type);
return (ISC_R_SUCCESS);
cleanup_socket:
isc_socket_detach(&query->tcpsocket);
cleanup_dispatch:
if (query->dispatch != NULL)
dns_dispatch_detach(&query->dispatch);
cleanup_rmessage:
dns_message_detach(&query->rmessage);
cleanup_query:
if (query->connects == 0) {
query->magic = 0;
isc_mem_put(fctx->mctx, query, sizeof(*query));
}
stop_idle_timer:
RUNTIME_CHECK(fctx_stopidletimer(fctx) == ISC_R_SUCCESS);
return (result);
}
static bool
bad_edns(fetchctx_t *fctx, isc_sockaddr_t *address) {
isc_sockaddr_t *sa;
for (sa = ISC_LIST_HEAD(fctx->bad_edns);
sa != NULL;
sa = ISC_LIST_NEXT(sa, link)) {
if (isc_sockaddr_equal(sa, address))
return (true);
}
return (false);
}
static void
add_bad_edns(fetchctx_t *fctx, isc_sockaddr_t *address) {
isc_sockaddr_t *sa;
#ifdef ENABLE_AFL
if (dns_fuzzing_resolver)
return;
#endif
if (bad_edns(fctx, address))
return;
sa = isc_mem_get(fctx->mctx, sizeof(*sa));
if (sa == NULL)
return;
*sa = *address;
ISC_LIST_INITANDAPPEND(fctx->bad_edns, sa, link);
}
static struct tried *
triededns(fetchctx_t *fctx, isc_sockaddr_t *address) {
struct tried *tried;
for (tried = ISC_LIST_HEAD(fctx->edns);
tried != NULL;
tried = ISC_LIST_NEXT(tried, link)) {
if (isc_sockaddr_equal(&tried->addr, address))
return (tried);
}
return (NULL);
}
static void
add_triededns(fetchctx_t *fctx, isc_sockaddr_t *address) {
struct tried *tried;
tried = triededns(fctx, address);
if (tried != NULL) {
tried->count++;
return;
}
tried = isc_mem_get(fctx->mctx, sizeof(*tried));
if (tried == NULL)
return;
tried->addr = *address;
tried->count = 1;
ISC_LIST_INITANDAPPEND(fctx->edns, tried, link);
}
static struct tried *
triededns512(fetchctx_t *fctx, isc_sockaddr_t *address) {
struct tried *tried;
for (tried = ISC_LIST_HEAD(fctx->edns512);
tried != NULL;
tried = ISC_LIST_NEXT(tried, link)) {
if (isc_sockaddr_equal(&tried->addr, address))
return (tried);
}
return (NULL);
}
static void
add_triededns512(fetchctx_t *fctx, isc_sockaddr_t *address) {
struct tried *tried;
tried = triededns512(fctx, address);
if (tried != NULL) {
tried->count++;
return;
}
tried = isc_mem_get(fctx->mctx, sizeof(*tried));
if (tried == NULL)
return;
tried->addr = *address;
tried->count = 1;
ISC_LIST_INITANDAPPEND(fctx->edns512, tried, link);
}
static inline size_t
addr2buf(void *buf, const size_t bufsize, const isc_sockaddr_t *sockaddr) {
isc_netaddr_t netaddr;
isc_netaddr_fromsockaddr(&netaddr, sockaddr);
switch (netaddr.family) {
case AF_INET:
INSIST(bufsize >= 4);
memmove(buf, &netaddr.type.in, 4);
return (4);
case AF_INET6:
INSIST(bufsize >= 16);
memmove(buf, &netaddr.type.in6, 16);
return (16);
default:
INSIST(0);
ISC_UNREACHABLE();
}
return (0);
}
static inline size_t
add_serveraddr(uint8_t *buf, const size_t bufsize, const resquery_t *query)
{
return (addr2buf(buf, bufsize, &query->addrinfo->sockaddr));
}
/*
* Client cookie is 8 octets.
* Server cookie is [8..32] octets.
*/
#define CLIENT_COOKIE_SIZE 8U
#define COOKIE_BUFFER_SIZE (8U + 32U)
static void
compute_cc(const resquery_t *query, uint8_t *cookie, const size_t len) {
INSIST(len >= CLIENT_COOKIE_SIZE);
INSIST(sizeof(query->fctx->res->view->secret)
>= ISC_SIPHASH24_KEY_LENGTH);
uint8_t buf[16] = { 0 };
size_t buflen = add_serveraddr(buf, sizeof(buf), query);
uint8_t digest[ISC_SIPHASH24_TAG_LENGTH] = { 0 };
isc_siphash24(query->fctx->res->view->secret, buf, buflen, digest);
memmove(cookie, digest, CLIENT_COOKIE_SIZE);
}
static isc_result_t
issecuredomain(dns_view_t *view, dns_name_t *name, dns_rdatatype_t type,
isc_stdtime_t now, bool checknta, bool *ntap, bool *issecure)
{
dns_name_t suffix;
unsigned int labels;
/*
* For DS variants we need to check fom the parent domain,
* since there may be a negative trust anchor for the name,
* while the enclosing domain where the DS record lives is
* under a secure entry point.
*/
labels = dns_name_countlabels(name);
if (dns_rdatatype_atparent(type) && labels > 1) {
dns_name_init(&suffix, NULL);
dns_name_getlabelsequence(name, 1, labels - 1, &suffix);
name = &suffix;
}
return (dns_view_issecuredomain(view, name, now, checknta,
ntap, issecure));
}
static bool
wouldvalidate(fetchctx_t *fctx) {
bool secure_domain;
isc_result_t result;
isc_stdtime_t now;
if (!fctx->res->view->enablevalidation) {
return (false);
}
if (fctx->res->view->dlv != NULL) {
return (true);
}
isc_stdtime_get(&now);
result = dns_view_issecuredomain(fctx->res->view, &fctx->name,
now, true, NULL, &secure_domain);
if (result != ISC_R_SUCCESS) {
return (false);
}
return (secure_domain);
}
static isc_result_t
resquery_send(resquery_t *query) {
fetchctx_t *fctx;
isc_result_t result;
dns_name_t *qname = NULL;
dns_rdataset_t *qrdataset = NULL;
isc_region_t r;
dns_resolver_t *res;
isc_task_t *task;
isc_socket_t *sock;
isc_buffer_t tcpbuffer;
isc_sockaddr_t *address;
isc_buffer_t *buffer;
isc_netaddr_t ipaddr;
dns_tsigkey_t *tsigkey = NULL;
dns_peer_t *peer = NULL;
bool useedns;
dns_compress_t cctx;
bool cleanup_cctx = false;
bool secure_domain;
bool connecting = false;
bool tcp = ((query->options & DNS_FETCHOPT_TCP) != 0);
dns_ednsopt_t ednsopts[DNS_EDNSOPTIONS];
unsigned ednsopt = 0;
uint16_t hint = 0, udpsize = 0; /* No EDNS */
#ifdef HAVE_DNSTAP
isc_sockaddr_t localaddr, *la = NULL;
unsigned char zone[DNS_NAME_MAXWIRE];
dns_dtmsgtype_t dtmsgtype;
isc_region_t zr;
isc_buffer_t zb;
#endif /* HAVE_DNSTAP */
fctx = query->fctx;
QTRACE("send");
res = fctx->res;
task = res->buckets[fctx->bucketnum].task;
address = NULL;
if (tcp) {
/*
* Reserve space for the TCP message length.
*/
isc_buffer_init(&tcpbuffer, query->data, sizeof(query->data));
isc_buffer_init(&query->buffer, query->data + 2,
sizeof(query->data) - 2);
buffer = &tcpbuffer;
} else {
isc_buffer_init(&query->buffer, query->data,
sizeof(query->data));
buffer = &query->buffer;
}
result = dns_message_gettempname(fctx->qmessage, &qname);
if (result != ISC_R_SUCCESS)
goto cleanup_temps;
result = dns_message_gettemprdataset(fctx->qmessage, &qrdataset);
if (result != ISC_R_SUCCESS)
goto cleanup_temps;
/*
* Get a query id from the dispatch.
*/
result = dns_dispatch_addresponse2(query->dispatch,
&query->addrinfo->sockaddr,
task,
resquery_response,
query,
&query->id,
&query->dispentry,
res->socketmgr);
if (result != ISC_R_SUCCESS)
goto cleanup_temps;
fctx->qmessage->opcode = dns_opcode_query;
/*
* Set up question.
*/
dns_name_init(qname, NULL);
dns_name_clone(&fctx->name, qname);
dns_rdataset_makequestion(qrdataset, res->rdclass, fctx->type);
ISC_LIST_APPEND(qname->list, qrdataset, link);
dns_message_addname(fctx->qmessage, qname, DNS_SECTION_QUESTION);
qname = NULL;
qrdataset = NULL;
/*
* Set RD if the client has requested that we do a recursive query,
* or if we're sending to a forwarder.
*/
if ((query->options & DNS_FETCHOPT_RECURSIVE) != 0 ||
ISFORWARDER(query->addrinfo))
fctx->qmessage->flags |= DNS_MESSAGEFLAG_RD;
/*
* Set CD if the client says not to validate, or if the
* question is under a secure entry point and this is a
* recursive/forward query -- unless the client said not to.
*/
if ((query->options & DNS_FETCHOPT_NOCDFLAG) != 0) {
/* Do nothing */
} else if ((query->options & DNS_FETCHOPT_NOVALIDATE) != 0) {
fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD;
} else if (res->view->enablevalidation &&
((fctx->qmessage->flags & DNS_MESSAGEFLAG_RD) != 0))
{
bool checknta = !NONTA(query->options);
bool ntacovered = false;
result = issecuredomain(res->view, &fctx->name, fctx->type,
isc_time_seconds(&query->start),
checknta, &ntacovered, &secure_domain);
if (result != ISC_R_SUCCESS) {
secure_domain = false;
}
if (res->view->dlv != NULL) {
secure_domain = true;
}
if (secure_domain ||
(ISFORWARDER(query->addrinfo) && ntacovered))
{
fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD;
}
}
/*
* We don't have to set opcode because it defaults to query.
*/
fctx->qmessage->id = query->id;
/*
* Convert the question to wire format.
*/
result = dns_compress_init(&cctx, -1, fctx->res->mctx);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
cleanup_cctx = true;
result = dns_message_renderbegin(fctx->qmessage, &cctx,
&query->buffer);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
result = dns_message_rendersection(fctx->qmessage,
DNS_SECTION_QUESTION, 0);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
peer = NULL;
isc_netaddr_fromsockaddr(&ipaddr, &query->addrinfo->sockaddr);
(void) dns_peerlist_peerbyaddr(fctx->res->view->peers, &ipaddr, &peer);
/*
* The ADB does not know about servers with "edns no". Check this,
* and then inform the ADB for future use.
*/
if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0 &&
peer != NULL &&
dns_peer_getsupportedns(peer, &useedns) == ISC_R_SUCCESS &&
!useedns)
{
query->options |= DNS_FETCHOPT_NOEDNS0;
dns_adb_changeflags(fctx->adb, query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
}
/* Sync NOEDNS0 flag in addrinfo->flags and options now. */
if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) != 0)
query->options |= DNS_FETCHOPT_NOEDNS0;
/* See if response history indicates that EDNS is not supported. */
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0 &&
dns_adb_noedns(fctx->adb, query->addrinfo))
query->options |= DNS_FETCHOPT_NOEDNS0;
if (fctx->timeout && (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
isc_sockaddr_t *sockaddr = &query->addrinfo->sockaddr;
struct tried *tried;
if (fctx->timeouts > (MAX_EDNS0_TIMEOUTS * 2) &&
(!EDNSOK(query->addrinfo) || !wouldvalidate(fctx))) {
query->options |= DNS_FETCHOPT_NOEDNS0;
fctx->reason = "disabling EDNS";
} else if ((tried = triededns512(fctx, sockaddr)) != NULL &&
tried->count >= 2U &&
(!EDNSOK(query->addrinfo) || !wouldvalidate(fctx))) {
query->options |= DNS_FETCHOPT_NOEDNS0;
fctx->reason = "disabling EDNS";
} else if ((tried = triededns(fctx, sockaddr)) != NULL) {
if (tried->count == 1U) {
hint = dns_adb_getudpsize(fctx->adb,
query->addrinfo);
} else if (tried->count >= 2U) {
query->options |= DNS_FETCHOPT_EDNS512;
fctx->reason = "reducing the advertised EDNS "
"UDP packet size to 512 octets";
}
}
}
fctx->timeout = false;
/*
* Use EDNS0, unless the caller doesn't want it, or we know that
* the remote server doesn't like it.
*/
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0) {
unsigned int version = DNS_EDNS_VERSION;
unsigned int flags = query->addrinfo->flags;
bool reqnsid = res->view->requestnsid;
bool sendcookie = res->view->sendcookie;
unsigned char cookie[COOKIE_BUFFER_SIZE];
if ((flags & FCTX_ADDRINFO_EDNSOK) != 0 &&
(query->options & DNS_FETCHOPT_EDNS512) == 0) {
udpsize = dns_adb_probesize2(fctx->adb,
query->addrinfo,
fctx->timeouts);
if (udpsize > res->udpsize)
udpsize = res->udpsize;
}
if (peer != NULL)
(void)dns_peer_getudpsize(peer, &udpsize);
if (udpsize == 0U && res->udpsize == 512U)
udpsize = 512;
/*
* Was the size forced to 512 in the configuration?
*/
if (udpsize == 512U)
query->options |= DNS_FETCHOPT_EDNS512;
/*
* We have talked to this server before.
*/
if (hint != 0U)
udpsize = hint;
/*
* We know nothing about the peer's capabilities
* so start with minimal EDNS UDP size.
*/
if (udpsize == 0U)
udpsize = 512;
if ((flags & DNS_FETCHOPT_EDNSVERSIONSET) != 0) {
version = flags & DNS_FETCHOPT_EDNSVERSIONMASK;
version >>= DNS_FETCHOPT_EDNSVERSIONSHIFT;
}
/* Request NSID/COOKIE/VERSION for current peer? */
if (peer != NULL) {
uint8_t ednsversion;
(void) dns_peer_getrequestnsid(peer, &reqnsid);
(void) dns_peer_getsendcookie(peer,
&sendcookie);
result = dns_peer_getednsversion(peer,
&ednsversion);
if (result == ISC_R_SUCCESS &&
ednsversion < version)
version = ednsversion;
}
if (NOCOOKIE(query->addrinfo))
sendcookie = false;
if (reqnsid) {
INSIST(ednsopt < DNS_EDNSOPTIONS);
ednsopts[ednsopt].code = DNS_OPT_NSID;
ednsopts[ednsopt].length = 0;
ednsopts[ednsopt].value = NULL;
ednsopt++;
}
#if DNS_EDNS_VERSION > 0
/*
* Some EDNS(0) servers don't ignore unknown options
* as it was not a explicit requirement of RFC 2671.
* Only send COOKIE to EDNS(1) servers.
*/
if (version < 1)
sendcookie = false;
#endif
if (sendcookie) {
INSIST(ednsopt < DNS_EDNSOPTIONS);
ednsopts[ednsopt].code = DNS_OPT_COOKIE;
ednsopts[ednsopt].length = (uint16_t)
dns_adb_getcookie(fctx->adb,
query->addrinfo,
cookie,
sizeof(cookie));
if (ednsopts[ednsopt].length != 0) {
ednsopts[ednsopt].value = cookie;
inc_stats(fctx->res,
dns_resstatscounter_cookieout);
} else {
compute_cc(query, cookie,
CLIENT_COOKIE_SIZE);
ednsopts[ednsopt].value = cookie;
ednsopts[ednsopt].length =
CLIENT_COOKIE_SIZE;
inc_stats(fctx->res,
dns_resstatscounter_cookienew);
}
ednsopt++;
}
query->ednsversion = version;
result = fctx_addopt(fctx->qmessage, version,
udpsize, ednsopts, ednsopt);
if (reqnsid && result == ISC_R_SUCCESS) {
query->options |= DNS_FETCHOPT_WANTNSID;
} else if (result != ISC_R_SUCCESS) {
/*
* We couldn't add the OPT, but we'll press on.
* We're not using EDNS0, so set the NOEDNS0
* bit.
*/
query->options |= DNS_FETCHOPT_NOEDNS0;
query->ednsversion = -1;
udpsize = 0;
}
} else {
/*
* We know this server doesn't like EDNS0, so we
* won't use it. Set the NOEDNS0 bit since we're
* not using EDNS0.
*/
query->options |= DNS_FETCHOPT_NOEDNS0;
query->ednsversion = -1;
}
} else
query->ednsversion = -1;
/*
* Record the UDP EDNS size chosen.
*/
query->udpsize = udpsize;
/*
* If we need EDNS0 to do this query and aren't using it, we lose.
*/
if (NEEDEDNS0(fctx) && (query->options & DNS_FETCHOPT_NOEDNS0) != 0) {
result = DNS_R_SERVFAIL;
goto cleanup_message;
}
if (udpsize > 512U)
add_triededns(fctx, &query->addrinfo->sockaddr);
if (udpsize == 512U)
add_triededns512(fctx, &query->addrinfo->sockaddr);
/*
* Clear CD if EDNS is not in use.
*/
if ((query->options & DNS_FETCHOPT_NOEDNS0) != 0)
fctx->qmessage->flags &= ~DNS_MESSAGEFLAG_CD;
/*
* Add TSIG record tailored to the current recipient.
*/
result = dns_view_getpeertsig(fctx->res->view, &ipaddr, &tsigkey);
if (result != ISC_R_SUCCESS && result != ISC_R_NOTFOUND)
goto cleanup_message;
if (tsigkey != NULL) {
result = dns_message_settsigkey(fctx->qmessage, tsigkey);
dns_tsigkey_detach(&tsigkey);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
}
result = dns_message_rendersection(fctx->qmessage,
DNS_SECTION_ADDITIONAL, 0);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
result = dns_message_renderend(fctx->qmessage);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
#ifdef HAVE_DNSTAP
memset(&zr, 0, sizeof(zr));
isc_buffer_init(&zb, zone, sizeof(zone));
dns_compress_setmethods(&cctx, DNS_COMPRESS_NONE);
result = dns_name_towire(&fctx->domain, &cctx, &zb);
if (result == ISC_R_SUCCESS)
isc_buffer_usedregion(&zb, &zr);
#endif /* HAVE_DNSTAP */
dns_compress_invalidate(&cctx);
cleanup_cctx = false;
if (dns_message_gettsigkey(fctx->qmessage) != NULL) {
dns_tsigkey_attach(dns_message_gettsigkey(fctx->qmessage),
&query->tsigkey);
result = dns_message_getquerytsig(fctx->qmessage,
fctx->res->mctx,
&query->tsig);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
}
/*
* If using TCP, write the length of the message at the beginning
* of the buffer.
*/
if (tcp) {
isc_buffer_usedregion(&query->buffer, &r);
isc_buffer_putuint16(&tcpbuffer, (uint16_t)r.length);
isc_buffer_add(&tcpbuffer, r.length);
}
/*
* Log the outgoing packet.
*/
dns_message_logfmtpacket2(fctx->qmessage, "sending packet to",
&query->addrinfo->sockaddr,
DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_PACKETS,
&dns_master_style_comment,
ISC_LOG_DEBUG(11),
fctx->res->mctx);
/*
* We're now done with the query message.
*/
dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
if (query->exclusivesocket) {
sock = dns_dispatch_getentrysocket(query->dispentry);
} else {
sock = dns_dispatch_getsocket(query->dispatch);
}
/*
* Send the query!
*/
if (!tcp) {
address = &query->addrinfo->sockaddr;
if (query->exclusivesocket) {
result = isc_socket_connect(sock, address, task,
resquery_udpconnected,
query);
if (result != ISC_R_SUCCESS)
goto cleanup_message;
connecting = true;
query->connects++;
}
}
isc_buffer_usedregion(buffer, &r);
/*
* XXXRTH Make sure we don't send to ourselves! We should probably
* prune out these addresses when we get them from the ADB.
*/
memset(&query->sendevent, 0, sizeof(query->sendevent));
ISC_EVENT_INIT(&query->sendevent, sizeof(query->sendevent), 0, NULL,
ISC_SOCKEVENT_SENDDONE, resquery_senddone, query,
NULL, NULL, NULL);
if (query->dscp == -1) {
query->sendevent.attributes &= ~ISC_SOCKEVENTATTR_DSCP;
query->sendevent.dscp = 0;
} else {
query->sendevent.attributes |= ISC_SOCKEVENTATTR_DSCP;
query->sendevent.dscp = query->dscp;
if (tcp)
isc_socket_dscp(sock, query->dscp);
}
result = isc_socket_sendto2(sock, &r, task, address, NULL,
&query->sendevent, 0);
if (result != ISC_R_SUCCESS) {
if (connecting) {
/*
* This query is still connecting.
* Mark it as canceled so that it will just be
* cleaned up when the connected event is received.
* Keep fctx around until the event is processed.
*/
query->fctx->nqueries++;
query->attributes |= RESQUERY_ATTR_CANCELED;
}
goto cleanup_message;
}
query->sends++;
QTRACE("sent");
#ifdef HAVE_DNSTAP
/*
* Log the outgoing query via dnstap.
*/
if ((fctx->qmessage->flags & DNS_MESSAGEFLAG_RD) != 0)
dtmsgtype = DNS_DTTYPE_FQ;
else
dtmsgtype = DNS_DTTYPE_RQ;
result = isc_socket_getsockname(sock, &localaddr);
if (result == ISC_R_SUCCESS)
la = &localaddr;
dns_dt_send(fctx->res->view, dtmsgtype, la, &query->addrinfo->sockaddr,
tcp, &zr, &query->start, NULL, &query->buffer);
#endif /* HAVE_DNSTAP */
return (ISC_R_SUCCESS);
cleanup_message:
if (cleanup_cctx)
dns_compress_invalidate(&cctx);
dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
/*
* Stop the dispatcher from listening.
*/
dns_dispatch_removeresponse(&query->dispentry, NULL);
cleanup_temps:
if (qname != NULL)
dns_message_puttempname(fctx->qmessage, &qname);
if (qrdataset != NULL)
dns_message_puttemprdataset(fctx->qmessage, &qrdataset);
return (result);
}
static void
resquery_connected(isc_task_t *task, isc_event_t *event) {
isc_socketevent_t *sevent = (isc_socketevent_t *)event;
resquery_t *query = event->ev_arg;
bool retry = false;
isc_interval_t interval;
isc_result_t result;
unsigned int attrs;
fetchctx_t *fctx;
REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
REQUIRE(VALID_QUERY(query));
QTRACE("connected");
UNUSED(task);
/*
* XXXRTH
*
* Currently we don't wait for the connect event before retrying
* a query. This means that if we get really behind, we may end
* up doing extra work!
*/
query->connects--;
fctx = query->fctx;
if (RESQUERY_CANCELED(query)) {
/*
* This query was canceled while the connect() was in
* progress.
*/
isc_socket_detach(&query->tcpsocket);
resquery_destroy(&query);
} else {
switch (sevent->result) {
case ISC_R_SUCCESS:
/*
* Extend the idle timer for TCP. 20 seconds
* should be long enough for a TCP connection to be
* established, a single DNS request to be sent,
* and the response received.
*/
isc_interval_set(&interval, 20, 0);
result = fctx_startidletimer(query->fctx, &interval);
if (result != ISC_R_SUCCESS) {
FCTXTRACE("query canceled: idle timer failed; "
"responding");
fctx_cancelquery(&query, NULL, NULL, false,
false);
fctx_done(fctx, result, __LINE__);
break;
}
/*
* We are connected. Create a dispatcher and
* send the query.
*/
attrs = 0;
attrs |= DNS_DISPATCHATTR_TCP;
attrs |= DNS_DISPATCHATTR_PRIVATE;
attrs |= DNS_DISPATCHATTR_CONNECTED;
if (isc_sockaddr_pf(&query->addrinfo->sockaddr) ==
AF_INET)
attrs |= DNS_DISPATCHATTR_IPV4;
else
attrs |= DNS_DISPATCHATTR_IPV6;
attrs |= DNS_DISPATCHATTR_MAKEQUERY;
result = dns_dispatch_createtcp(query->dispatchmgr,
query->tcpsocket,
query->fctx->res->taskmgr,
4096, 2, 1, 1, 3, attrs,
&query->dispatch);
/*
* Regardless of whether dns_dispatch_create()
* succeeded or not, we don't need our reference
* to the socket anymore.
*/
isc_socket_detach(&query->tcpsocket);
if (result == ISC_R_SUCCESS)
result = resquery_send(query);
if (result != ISC_R_SUCCESS) {
FCTXTRACE("query canceled: "
"resquery_send() failed; responding");
fctx_cancelquery(&query, NULL, NULL, false, false);
fctx_done(fctx, result, __LINE__);
}
break;
case ISC_R_NETUNREACH:
case ISC_R_HOSTUNREACH:
case ISC_R_CONNREFUSED:
case ISC_R_NOPERM:
case ISC_R_ADDRNOTAVAIL:
case ISC_R_CONNECTIONRESET:
FCTXTRACE3("query canceled in connected(): "
"no route to host; no response",
sevent->result);
/*
* No route to remote.
*/
isc_socket_detach(&query->tcpsocket);
/*
* Do not query this server again in this fetch context
* if we already tried reducing the advertised EDNS UDP
* payload size to 512 bytes and the server is
* unavailable over TCP. This prevents query loops
* lasting until the fetch context restart limit is
* reached when attempting to get answers whose size
* exceeds 512 bytes from broken servers.
*/
if ((query->options & DNS_FETCHOPT_EDNS512) != 0) {
add_bad(fctx, query->rmessage,
query->addrinfo, sevent->result,
badns_unreachable);
}
fctx_cancelquery(&query, NULL, NULL, true, false);
retry = true;
break;
default:
FCTXTRACE3("query canceled in connected() due to "
"unexpected event result; responding",
sevent->result);
isc_socket_detach(&query->tcpsocket);
fctx_cancelquery(&query, NULL, NULL, false, false);
break;
}
}
isc_event_free(&event);
if (retry) {
/*
* Behave as if the idle timer has expired. For TCP
* connections this may not actually reflect the latest timer.
*/
FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT);
result = fctx_stopidletimer(fctx);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result, __LINE__);
else
fctx_try(fctx, true, false);
}
}
static void
fctx_finddone(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx;
dns_adbfind_t *find;
dns_resolver_t *res;
bool want_try = false;
bool want_done = false;
bool bucket_empty = false;
unsigned int bucketnum;
bool dodestroy = false;
find = event->ev_sender;
fctx = event->ev_arg;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
UNUSED(task);
FCTXTRACE("finddone");
bucketnum = fctx->bucketnum;
LOCK(&res->buckets[bucketnum].lock);
INSIST(fctx->pending > 0);
fctx->pending--;
if (ADDRWAIT(fctx)) {
/*
* The fetch is waiting for a name to be found.
*/
INSIST(!fctx->shuttingdown);
if (event->ev_type == DNS_EVENT_ADBMOREADDRESSES) {
FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT);
want_try = true;
} else {
fctx->findfail++;
if (fctx->pending == 0) {
/*
* We've got nothing else to wait for and don't
* know the answer. There's nothing to do but
* fail the fctx.
*/
FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT);
want_done = true;
}
}
} else if (fctx->shuttingdown && fctx->pending == 0 &&
fctx->nqueries == 0 && ISC_LIST_EMPTY(fctx->validators)) {
if (fctx->references == 0) {
bucket_empty = fctx_unlink(fctx);
dodestroy = true;
}
}
UNLOCK(&res->buckets[bucketnum].lock);
isc_event_free(&event);
dns_adb_destroyfind(&find);
if (want_try) {
fctx_try(fctx, true, false);
} else if (want_done) {
FCTXTRACE("fetch failed in finddone(); return ISC_R_FAILURE");
fctx_done(fctx, ISC_R_FAILURE, __LINE__);
} else if (dodestroy) {
fctx_destroy(fctx);
if (bucket_empty)
empty_bucket(res);
}
}
static inline bool
bad_server(fetchctx_t *fctx, isc_sockaddr_t *address) {
isc_sockaddr_t *sa;
for (sa = ISC_LIST_HEAD(fctx->bad);
sa != NULL;
sa = ISC_LIST_NEXT(sa, link)) {
if (isc_sockaddr_equal(sa, address))
return (true);
}
return (false);
}
static inline bool
mark_bad(fetchctx_t *fctx) {
dns_adbfind_t *curr;
dns_adbaddrinfo_t *addrinfo;
bool all_bad = true;
#ifdef ENABLE_AFL
if (dns_fuzzing_resolver)
return false;
#endif
/*
* Mark all known bad servers, so we don't try to talk to them
* again.
*/
/*
* Mark any bad nameservers.
*/
for (curr = ISC_LIST_HEAD(fctx->finds);
curr != NULL;
curr = ISC_LIST_NEXT(curr, publink)) {
for (addrinfo = ISC_LIST_HEAD(curr->list);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (bad_server(fctx, &addrinfo->sockaddr))
addrinfo->flags |= FCTX_ADDRINFO_MARK;
else
all_bad = false;
}
}
/*
* Mark any bad forwarders.
*/
for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (bad_server(fctx, &addrinfo->sockaddr))
addrinfo->flags |= FCTX_ADDRINFO_MARK;
else
all_bad = false;
}
/*
* Mark any bad alternates.
*/
for (curr = ISC_LIST_HEAD(fctx->altfinds);
curr != NULL;
curr = ISC_LIST_NEXT(curr, publink)) {
for (addrinfo = ISC_LIST_HEAD(curr->list);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (bad_server(fctx, &addrinfo->sockaddr))
addrinfo->flags |= FCTX_ADDRINFO_MARK;
else
all_bad = false;
}
}
for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (bad_server(fctx, &addrinfo->sockaddr))
addrinfo->flags |= FCTX_ADDRINFO_MARK;
else
all_bad = false;
}
return (all_bad);
}
static void
add_bad(fetchctx_t *fctx, dns_message_t *rmessage, dns_adbaddrinfo_t *addrinfo,
isc_result_t reason, badnstype_t badtype)
{
char namebuf[DNS_NAME_FORMATSIZE];
char addrbuf[ISC_SOCKADDR_FORMATSIZE];
char classbuf[64];
char typebuf[64];
char code[64];
isc_buffer_t b;
isc_sockaddr_t *sa;
const char *spc = "";
isc_sockaddr_t *address = &addrinfo->sockaddr;
#ifdef ENABLE_AFL
if (dns_fuzzing_resolver)
return;
#endif
if (reason == DNS_R_LAME)
fctx->lamecount++;
else {
switch (badtype) {
case badns_unreachable:
fctx->neterr++;
break;
case badns_response:
fctx->badresp++;
break;
case badns_validation:
break; /* counted as 'valfail' */
case badns_forwarder:
/*
* We were called to prevent the given forwarder from
* being used again for this fetch context.
*/
break;
}
}
if (bad_server(fctx, address)) {
/*
* We already know this server is bad.
*/
return;
}
FCTXTRACE("add_bad");
sa = isc_mem_get(fctx->mctx, sizeof(*sa));
if (sa == NULL)
return;
*sa = *address;
ISC_LIST_INITANDAPPEND(fctx->bad, sa, link);
if (reason == DNS_R_LAME) /* already logged */
return;
if (reason == DNS_R_UNEXPECTEDRCODE &&
rmessage->rcode == dns_rcode_servfail &&
ISFORWARDER(addrinfo))
return;
if (reason == DNS_R_UNEXPECTEDRCODE) {
isc_buffer_init(&b, code, sizeof(code) - 1);
dns_rcode_totext(rmessage->rcode, &b);
code[isc_buffer_usedlength(&b)] = '\0';
spc = " ";
} else if (reason == DNS_R_UNEXPECTEDOPCODE) {
isc_buffer_init(&b, code, sizeof(code) - 1);
dns_opcode_totext((dns_opcode_t)rmessage->opcode, &b);
code[isc_buffer_usedlength(&b)] = '\0';
spc = " ";
} else {
code[0] = '\0';
}
dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
dns_rdatatype_format(fctx->type, typebuf, sizeof(typebuf));
dns_rdataclass_format(fctx->res->rdclass, classbuf, sizeof(classbuf));
isc_sockaddr_format(address, addrbuf, sizeof(addrbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"%s%s%s resolving '%s/%s/%s': %s",
code, spc, dns_result_totext(reason),
namebuf, typebuf, classbuf, addrbuf);
}
/*
* Sort addrinfo list by RTT.
*/
static void
sort_adbfind(dns_adbfind_t *find, unsigned int bias) {
dns_adbaddrinfo_t *best, *curr;
dns_adbaddrinfolist_t sorted;
unsigned int best_srtt, curr_srtt;
/* Lame N^2 bubble sort. */
ISC_LIST_INIT(sorted);
while (!ISC_LIST_EMPTY(find->list)) {
best = ISC_LIST_HEAD(find->list);
best_srtt = best->srtt;
if (isc_sockaddr_pf(&best->sockaddr) != AF_INET6)
best_srtt += bias;
curr = ISC_LIST_NEXT(best, publink);
while (curr != NULL) {
curr_srtt = curr->srtt;
if (isc_sockaddr_pf(&curr->sockaddr) != AF_INET6)
curr_srtt += bias;
if (curr_srtt < best_srtt) {
best = curr;
best_srtt = curr_srtt;
}
curr = ISC_LIST_NEXT(curr, publink);
}
ISC_LIST_UNLINK(find->list, best, publink);
ISC_LIST_APPEND(sorted, best, publink);
}
find->list = sorted;
}
/*
* Sort a list of finds by server RTT.
*/
static void
sort_finds(dns_adbfindlist_t *findlist, unsigned int bias) {
dns_adbfind_t *best, *curr;
dns_adbfindlist_t sorted;
dns_adbaddrinfo_t *addrinfo, *bestaddrinfo;
unsigned int best_srtt, curr_srtt;
/* Sort each find's addrinfo list by SRTT. */
for (curr = ISC_LIST_HEAD(*findlist);
curr != NULL;
curr = ISC_LIST_NEXT(curr, publink))
sort_adbfind(curr, bias);
/* Lame N^2 bubble sort. */
ISC_LIST_INIT(sorted);
while (!ISC_LIST_EMPTY(*findlist)) {
best = ISC_LIST_HEAD(*findlist);
bestaddrinfo = ISC_LIST_HEAD(best->list);
INSIST(bestaddrinfo != NULL);
best_srtt = bestaddrinfo->srtt;
if (isc_sockaddr_pf(&bestaddrinfo->sockaddr) != AF_INET6)
best_srtt += bias;
curr = ISC_LIST_NEXT(best, publink);
while (curr != NULL) {
addrinfo = ISC_LIST_HEAD(curr->list);
INSIST(addrinfo != NULL);
curr_srtt = addrinfo->srtt;
if (isc_sockaddr_pf(&addrinfo->sockaddr) != AF_INET6)
curr_srtt += bias;
if (curr_srtt < best_srtt) {
best = curr;
best_srtt = curr_srtt;
}
curr = ISC_LIST_NEXT(curr, publink);
}
ISC_LIST_UNLINK(*findlist, best, publink);
ISC_LIST_APPEND(sorted, best, publink);
}
*findlist = sorted;
}
static void
findname(fetchctx_t *fctx, dns_name_t *name, in_port_t port,
unsigned int options, unsigned int flags, isc_stdtime_t now,
bool *overquota, bool *need_alternate, unsigned int *no_addresses) {
dns_adbaddrinfo_t *ai;
dns_adbfind_t *find;
dns_resolver_t *res;
bool unshared;
isc_result_t result;
res = fctx->res;
unshared = ((fctx->options & DNS_FETCHOPT_UNSHARED) != 0);
/*
* If this name is a subdomain of the query domain, tell
* the ADB to start looking using zone/hint data. This keeps us
* from getting stuck if the nameserver is beneath the zone cut
* and we don't know its address (e.g. because the A record has
* expired).
*/
if (dns_name_issubdomain(name, &fctx->domain))
options |= DNS_ADBFIND_STARTATZONE;
options |= DNS_ADBFIND_GLUEOK;
options |= DNS_ADBFIND_HINTOK;
/*
* See what we know about this address.
*/
find = NULL;
result = dns_adb_createfind2(fctx->adb,
res->buckets[fctx->bucketnum].task,
fctx_finddone, fctx, name,
&fctx->name, fctx->type,
options, now, NULL,
res->view->dstport,
fctx->depth + 1, fctx->qc, &find);
if (result != ISC_R_SUCCESS) {
if (result == DNS_R_ALIAS) {
char namebuf[DNS_NAME_FORMATSIZE];
/*
* XXXRTH Follow the CNAME/DNAME chain?
*/
dns_adb_destroyfind(&find);
fctx->adberr++;
dns_name_format(name, namebuf, sizeof(namebuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_CNAME,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"skipping nameserver '%s' because it "
"is a CNAME, while resolving '%s'",
namebuf, fctx->info);
}
} else if (!ISC_LIST_EMPTY(find->list)) {
/*
* We have at least some of the addresses for the
* name.
*/
INSIST((find->options & DNS_ADBFIND_WANTEVENT) == 0);
if (flags != 0 || port != 0) {
for (ai = ISC_LIST_HEAD(find->list);
ai != NULL;
ai = ISC_LIST_NEXT(ai, publink)) {
ai->flags |= flags;
if (port != 0)
isc_sockaddr_setport(&ai->sockaddr,
port);
}
}
if ((flags & FCTX_ADDRINFO_FORWARDER) != 0)
ISC_LIST_APPEND(fctx->altfinds, find, publink);
else
ISC_LIST_APPEND(fctx->finds, find, publink);
} else {
/*
* We don't know any of the addresses for this
* name.
*/
if ((find->options & DNS_ADBFIND_WANTEVENT) != 0) {
/*
* We're looking for them and will get an
* event about it later.
*/
fctx->pending++;
/*
* Bootstrap.
*/
if (need_alternate != NULL &&
!*need_alternate && unshared &&
((res->dispatches4 == NULL &&
find->result_v6 != DNS_R_NXDOMAIN) ||
(res->dispatches6 == NULL &&
find->result_v4 != DNS_R_NXDOMAIN)))
{
*need_alternate = true;
}
if (no_addresses != NULL) {
(*no_addresses)++;
}
} else {
if ((find->options & DNS_ADBFIND_OVERQUOTA) != 0) {
if (overquota != NULL)
*overquota = true;
fctx->quotacount++; /* quota exceeded */
}
else if ((find->options & DNS_ADBFIND_LAMEPRUNED) != 0)
fctx->lamecount++; /* cached lame server */
else
fctx->adberr++; /* unreachable server, etc. */
/*
* If we know there are no addresses for
* the family we are using then try to add
* an alternative server.
*/
if (need_alternate != NULL && !*need_alternate &&
((res->dispatches4 == NULL &&
find->result_v6 == DNS_R_NXRRSET) ||
(res->dispatches6 == NULL &&
find->result_v4 == DNS_R_NXRRSET)))
*need_alternate = true;
dns_adb_destroyfind(&find);
}
}
}
static bool
isstrictsubdomain(dns_name_t *name1, dns_name_t *name2) {
int order;
unsigned int nlabels;
dns_namereln_t namereln;
namereln = dns_name_fullcompare(name1, name2, &order, &nlabels);
return (namereln == dns_namereln_subdomain);
}
static isc_result_t
fctx_getaddresses(fetchctx_t *fctx, bool badcache) {
dns_rdata_t rdata = DNS_RDATA_INIT;
isc_result_t result;
dns_resolver_t *res;
isc_stdtime_t now;
unsigned int stdoptions = 0;
dns_forwarder_t *fwd;
dns_adbaddrinfo_t *ai;
bool all_bad;
dns_rdata_ns_t ns;
bool need_alternate = false;
bool all_spilled = true;
unsigned int no_addresses = 0;
FCTXTRACE5("getaddresses", "fctx->depth=", fctx->depth);
/*
* Don't pound on remote servers. (Failsafe!)
*/
fctx->restarts++;
if (fctx->restarts > 100) {
FCTXTRACE("too many restarts");
return (DNS_R_SERVFAIL);
}
res = fctx->res;
if (fctx->depth > res->maxdepth) {
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3),
"too much NS indirection resolving '%s' "
"(depth=%u, maxdepth=%u)",
fctx->info, fctx->depth, res->maxdepth);
return (DNS_R_SERVFAIL);
}
/*
* Forwarders.
*/
INSIST(ISC_LIST_EMPTY(fctx->forwaddrs));
INSIST(ISC_LIST_EMPTY(fctx->altaddrs));
/*
* If we have DNS_FETCHOPT_NOFORWARD set and forwarding policy
* allows us to not forward - skip forwarders and go straight
* to NSes. This is currently used to make sure that priming query
* gets root servers' IP addresses in ADDITIONAL section.
*/
if ((fctx->options & DNS_FETCHOPT_NOFORWARD) != 0 &&
(fctx->fwdpolicy != dns_fwdpolicy_only))
{
goto normal_nses;
}
/*
* If this fctx has forwarders, use them; otherwise use any
* selective forwarders specified in the view; otherwise use the
* resolver's forwarders (if any).
*/
fwd = ISC_LIST_HEAD(fctx->forwarders);
if (fwd == NULL) {
dns_forwarders_t *forwarders = NULL;
dns_name_t *name = &fctx->name;
dns_name_t suffix;
unsigned int labels;
dns_fixedname_t fixed;
dns_name_t *domain;
/*
* DS records are found in the parent server.
* Strip label to get the correct forwarder (if any).
*/
if (dns_rdatatype_atparent(fctx->type) &&
dns_name_countlabels(name) > 1) {
dns_name_init(&suffix, NULL);
labels = dns_name_countlabels(name);
dns_name_getlabelsequence(name, 1, labels - 1, &suffix);
name = &suffix;
}
domain = dns_fixedname_initname(&fixed);
result = dns_fwdtable_find2(res->view->fwdtable, name,
domain, &forwarders);
if (result == ISC_R_SUCCESS) {
fwd = ISC_LIST_HEAD(forwarders->fwdrs);
fctx->fwdpolicy = forwarders->fwdpolicy;
if (fctx->fwdpolicy == dns_fwdpolicy_only &&
isstrictsubdomain(domain, &fctx->domain)) {
fcount_decr(fctx);
dns_name_free(&fctx->domain, fctx->mctx);
dns_name_init(&fctx->domain, NULL);
result = dns_name_dup(domain, fctx->mctx,
&fctx->domain);
if (result != ISC_R_SUCCESS)
return (result);
result = fcount_incr(fctx, true);
if (result != ISC_R_SUCCESS)
return (result);
}
}
}
while (fwd != NULL) {
if ((isc_sockaddr_pf(&fwd->addr) == AF_INET &&
res->dispatches4 == NULL) ||
(isc_sockaddr_pf(&fwd->addr) == AF_INET6 &&
res->dispatches6 == NULL))
{
fwd = ISC_LIST_NEXT(fwd, link);
continue;
}
ai = NULL;
result = dns_adb_findaddrinfo(fctx->adb, &fwd->addr, &ai, 0);
if (result == ISC_R_SUCCESS) {
dns_adbaddrinfo_t *cur;
ai->flags |= FCTX_ADDRINFO_FORWARDER;
ai->dscp = fwd->dscp;
cur = ISC_LIST_HEAD(fctx->forwaddrs);
while (cur != NULL && cur->srtt < ai->srtt)
cur = ISC_LIST_NEXT(cur, publink);
if (cur != NULL)
ISC_LIST_INSERTBEFORE(fctx->forwaddrs, cur,
ai, publink);
else
ISC_LIST_APPEND(fctx->forwaddrs, ai, publink);
}
fwd = ISC_LIST_NEXT(fwd, link);
}
/*
* If the forwarding policy is "only", we don't need the addresses
* of the nameservers.
*/
if (fctx->fwdpolicy == dns_fwdpolicy_only)
goto out;
/*
* Normal nameservers.
*/
normal_nses:
stdoptions = DNS_ADBFIND_WANTEVENT | DNS_ADBFIND_EMPTYEVENT;
if (fctx->restarts == 1) {
/*
* To avoid sending out a flood of queries likely to
* result in NXRRSET, we suppress fetches for address
* families we don't have the first time through,
* provided that we have addresses in some family we
* can use.
*
* We don't want to set this option all the time, since
* if fctx->restarts > 1, we've clearly been having trouble
* with the addresses we had, so getting more could help.
*/
stdoptions |= DNS_ADBFIND_AVOIDFETCHES;
}
if (res->dispatches4 != NULL)
stdoptions |= DNS_ADBFIND_INET;
if (res->dispatches6 != NULL)
stdoptions |= DNS_ADBFIND_INET6;
if ((stdoptions & DNS_ADBFIND_ADDRESSMASK) == 0)
return (DNS_R_SERVFAIL);
isc_stdtime_get(&now);
INSIST(ISC_LIST_EMPTY(fctx->finds));
INSIST(ISC_LIST_EMPTY(fctx->altfinds));
for (result = dns_rdataset_first(&fctx->nameservers);
result == ISC_R_SUCCESS;
result = dns_rdataset_next(&fctx->nameservers))
{
bool overquota = false;
dns_rdataset_current(&fctx->nameservers, &rdata);
/*
* Extract the name from the NS record.
*/
result = dns_rdata_tostruct(&rdata, &ns, NULL);
if (result != ISC_R_SUCCESS) {
continue;
}
if (no_addresses > NS_FAIL_LIMIT &&
dns_rdataset_count(&fctx->nameservers) > NS_RR_LIMIT)
{
stdoptions |= DNS_ADBFIND_NOFETCH;
}
findname(fctx, &ns.name, 0, stdoptions, 0, now, &overquota,
&need_alternate, &no_addresses);
if (!overquota) {
all_spilled = false;
}
dns_rdata_reset(&rdata);
dns_rdata_freestruct(&ns);
}
if (result != ISC_R_NOMORE) {
return (result);
}
/*
* Do we need to use 6 to 4?
*/
if (need_alternate) {
int family;
alternate_t *a;
family = (res->dispatches6 != NULL) ? AF_INET6 : AF_INET;
for (a = ISC_LIST_HEAD(res->alternates);
a != NULL;
a = ISC_LIST_NEXT(a, link)) {
if (!a->isaddress) {
findname(fctx, &a->_u._n.name, a->_u._n.port,
stdoptions, FCTX_ADDRINFO_FORWARDER,
now, NULL, NULL, NULL);
continue;
}
if (isc_sockaddr_pf(&a->_u.addr) != family)
continue;
ai = NULL;
result = dns_adb_findaddrinfo(fctx->adb, &a->_u.addr,
&ai, 0);
if (result == ISC_R_SUCCESS) {
dns_adbaddrinfo_t *cur;
ai->flags |= FCTX_ADDRINFO_FORWARDER;
cur = ISC_LIST_HEAD(fctx->altaddrs);
while (cur != NULL && cur->srtt < ai->srtt)
cur = ISC_LIST_NEXT(cur, publink);
if (cur != NULL)
ISC_LIST_INSERTBEFORE(fctx->altaddrs,
cur, ai, publink);
else
ISC_LIST_APPEND(fctx->altaddrs, ai,
publink);
}
}
}
out:
/*
* Mark all known bad servers.
*/
all_bad = mark_bad(fctx);
/*
* How are we doing?
*/
if (all_bad) {
/*
* We've got no addresses.
*/
if (fctx->pending > 0) {
/*
* We're fetching the addresses, but don't have any
* yet. Tell the caller to wait for an answer.
*/
result = DNS_R_WAIT;
} else {
isc_time_t expire;
isc_interval_t i;
/*
* We've lost completely. We don't know any
* addresses, and the ADB has told us it can't get
* them.
*/
FCTXTRACE("no addresses");
isc_interval_set(&i, DNS_RESOLVER_BADCACHETTL(fctx), 0);
result = isc_time_nowplusinterval(&expire, &i);
if (badcache &&
(fctx->type == dns_rdatatype_dnskey ||
fctx->type == dns_rdatatype_dlv ||
fctx->type == dns_rdatatype_ds) &&
result == ISC_R_SUCCESS)
dns_resolver_addbadcache(res, &fctx->name,
fctx->type, &expire);
result = ISC_R_FAILURE;
/*
* If all of the addresses found were over the
* fetches-per-server quota, return the configured
* response.
*/
if (all_spilled) {
result = res->quotaresp[dns_quotatype_server];
inc_stats(res, dns_resstatscounter_serverquota);
}
}
} else {
/*
* We've found some addresses. We might still be looking
* for more addresses.
*/
sort_finds(&fctx->finds, res->view->v6bias);
sort_finds(&fctx->altfinds, 0);
result = ISC_R_SUCCESS;
}
return (result);
}
static inline void
possibly_mark(fetchctx_t *fctx, dns_adbaddrinfo_t *addr) {
isc_netaddr_t na;
char buf[ISC_NETADDR_FORMATSIZE];
isc_sockaddr_t *sa;
bool aborted = false;
bool bogus;
dns_acl_t *blackhole;
isc_netaddr_t ipaddr;
dns_peer_t *peer = NULL;
dns_resolver_t *res;
const char *msg = NULL;
sa = &addr->sockaddr;
res = fctx->res;
isc_netaddr_fromsockaddr(&ipaddr, sa);
blackhole = dns_dispatchmgr_getblackhole(res->dispatchmgr);
(void) dns_peerlist_peerbyaddr(res->view->peers, &ipaddr, &peer);
if (blackhole != NULL) {
int match;
if (dns_acl_match(&ipaddr, NULL, blackhole,
&res->view->aclenv,
&match, NULL) == ISC_R_SUCCESS &&
match > 0)
aborted = true;
}
if (peer != NULL &&
dns_peer_getbogus(peer, &bogus) == ISC_R_SUCCESS &&
bogus)
aborted = true;
if (aborted) {
addr->flags |= FCTX_ADDRINFO_MARK;
msg = "ignoring blackholed / bogus server: ";
} else if (isc_sockaddr_isnetzero(sa)) {
addr->flags |= FCTX_ADDRINFO_MARK;
msg = "ignoring net zero address: ";
} else if (isc_sockaddr_ismulticast(sa)) {
addr->flags |= FCTX_ADDRINFO_MARK;
msg = "ignoring multicast address: ";
} else if (isc_sockaddr_isexperimental(sa)) {
addr->flags |= FCTX_ADDRINFO_MARK;
msg = "ignoring experimental address: ";
} else if (sa->type.sa.sa_family != AF_INET6) {
return;
} else if (IN6_IS_ADDR_V4MAPPED(&sa->type.sin6.sin6_addr)) {
addr->flags |= FCTX_ADDRINFO_MARK;
msg = "ignoring IPv6 mapped IPV4 address: ";
} else if (IN6_IS_ADDR_V4COMPAT(&sa->type.sin6.sin6_addr)) {
addr->flags |= FCTX_ADDRINFO_MARK;
msg = "ignoring IPv6 compatibility IPV4 address: ";
} else
return;
if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(3))) {
isc_netaddr_fromsockaddr(&na, sa);
isc_netaddr_format(&na, buf, sizeof(buf));
FCTXTRACE2(msg, buf);
}
}
static inline dns_adbaddrinfo_t *
fctx_nextaddress(fetchctx_t *fctx) {
dns_adbfind_t *find, *start;
dns_adbaddrinfo_t *addrinfo;
dns_adbaddrinfo_t *faddrinfo;
/*
* Return the next untried address, if any.
*/
/*
* Find the first unmarked forwarder (if any).
*/
for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (!UNMARKED(addrinfo))
continue;
possibly_mark(fctx, addrinfo);
if (UNMARKED(addrinfo)) {
addrinfo->flags |= FCTX_ADDRINFO_MARK;
fctx->find = NULL;
return (addrinfo);
}
}
/*
* No forwarders. Move to the next find.
*/
FCTX_ATTR_SET(fctx, FCTX_ATTR_TRIEDFIND);
find = fctx->find;
if (find == NULL)
find = ISC_LIST_HEAD(fctx->finds);
else {
find = ISC_LIST_NEXT(find, publink);
if (find == NULL)
find = ISC_LIST_HEAD(fctx->finds);
}
/*
* Find the first unmarked addrinfo.
*/
addrinfo = NULL;
if (find != NULL) {
start = find;
do {
for (addrinfo = ISC_LIST_HEAD(find->list);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (!UNMARKED(addrinfo))
continue;
possibly_mark(fctx, addrinfo);
if (UNMARKED(addrinfo)) {
addrinfo->flags |= FCTX_ADDRINFO_MARK;
break;
}
}
if (addrinfo != NULL)
break;
find = ISC_LIST_NEXT(find, publink);
if (find == NULL)
find = ISC_LIST_HEAD(fctx->finds);
} while (find != start);
}
fctx->find = find;
if (addrinfo != NULL)
return (addrinfo);
/*
* No nameservers left. Try alternates.
*/
FCTX_ATTR_SET(fctx, FCTX_ATTR_TRIEDALT);
find = fctx->altfind;
if (find == NULL)
find = ISC_LIST_HEAD(fctx->altfinds);
else {
find = ISC_LIST_NEXT(find, publink);
if (find == NULL)
find = ISC_LIST_HEAD(fctx->altfinds);
}
/*
* Find the first unmarked addrinfo.
*/
addrinfo = NULL;
if (find != NULL) {
start = find;
do {
for (addrinfo = ISC_LIST_HEAD(find->list);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (!UNMARKED(addrinfo))
continue;
possibly_mark(fctx, addrinfo);
if (UNMARKED(addrinfo)) {
addrinfo->flags |= FCTX_ADDRINFO_MARK;
break;
}
}
if (addrinfo != NULL)
break;
find = ISC_LIST_NEXT(find, publink);
if (find == NULL)
find = ISC_LIST_HEAD(fctx->altfinds);
} while (find != start);
}
faddrinfo = addrinfo;
/*
* See if we have a better alternate server by address.
*/
for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
addrinfo != NULL;
addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
if (!UNMARKED(addrinfo))
continue;
possibly_mark(fctx, addrinfo);
if (UNMARKED(addrinfo) &&
(faddrinfo == NULL ||
addrinfo->srtt < faddrinfo->srtt)) {
if (faddrinfo != NULL)
faddrinfo->flags &= ~FCTX_ADDRINFO_MARK;
addrinfo->flags |= FCTX_ADDRINFO_MARK;
break;
}
}
if (addrinfo == NULL) {
addrinfo = faddrinfo;
fctx->altfind = find;
}
return (addrinfo);
}
static void
fctx_try(fetchctx_t *fctx, bool retrying, bool badcache) {
isc_result_t result;
dns_adbaddrinfo_t *addrinfo = NULL;
dns_resolver_t *res;
unsigned int bucketnum;
bool bucket_empty;
FCTXTRACE5("try", "fctx->qc=", isc_counter_used(fctx->qc));
REQUIRE(!ADDRWAIT(fctx));
res = fctx->res;
/* We've already exceeded maximum query count */
if (isc_counter_used(fctx->qc) > res->maxqueries) {
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3),
"exceeded max queries resolving '%s' "
"(querycount=%u, maxqueries=%u)",
fctx->info,
isc_counter_used(fctx->qc), res->maxqueries);
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
return;
}
addrinfo = fctx_nextaddress(fctx);
/* Try to find an address that isn't over quota */
while (addrinfo != NULL && dns_adbentry_overquota(fctx->adb, addrinfo->entry))
addrinfo = fctx_nextaddress(fctx);
if (addrinfo == NULL) {
/* We have no more addresses. Start over. */
fctx_cancelqueries(fctx, true, false);
fctx_cleanupall(fctx);
result = fctx_getaddresses(fctx, badcache);
if (result == DNS_R_WAIT) {
/*
* Sleep waiting for addresses.
*/
FCTXTRACE("addrwait");
FCTX_ATTR_SET(fctx, FCTX_ATTR_ADDRWAIT);
return;
} else if (result != ISC_R_SUCCESS) {
/*
* Something bad happened.
*/
fctx_done(fctx, result, __LINE__);
return;
}
addrinfo = fctx_nextaddress(fctx);
while (addrinfo != NULL &&
dns_adbentry_overquota(fctx->adb, addrinfo->entry))
addrinfo = fctx_nextaddress(fctx);
/*
* While we may have addresses from the ADB, they
* might be bad ones. In this case, return SERVFAIL.
*/
if (addrinfo == NULL) {
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
return;
}
}
result = isc_counter_increment(fctx->qc);
if (result != ISC_R_SUCCESS) {
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(3),
"exceeded max queries resolving '%s'",
fctx->info);
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
return;
}
bucketnum = fctx->bucketnum;
fctx_increference(fctx);
result = fctx_query(fctx, addrinfo, fctx->options);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, result, __LINE__);
LOCK(&res->buckets[bucketnum].lock);
bucket_empty = fctx_decreference(fctx);
UNLOCK(&res->buckets[bucketnum].lock);
if (bucket_empty)
empty_bucket(res);
} else if (retrying)
inc_stats(res, dns_resstatscounter_retry);
}
static bool
fctx_unlink(fetchctx_t *fctx) {
dns_resolver_t *res;
unsigned int bucketnum;
/*
* Caller must be holding the bucket lock.
*/
REQUIRE(VALID_FCTX(fctx));
REQUIRE(fctx->state == fetchstate_done ||
fctx->state == fetchstate_init);
REQUIRE(ISC_LIST_EMPTY(fctx->events));
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
REQUIRE(ISC_LIST_EMPTY(fctx->finds));
REQUIRE(ISC_LIST_EMPTY(fctx->altfinds));
REQUIRE(fctx->pending == 0);
REQUIRE(fctx->references == 0);
REQUIRE(ISC_LIST_EMPTY(fctx->validators));
FCTXTRACE("unlink");
res = fctx->res;
bucketnum = fctx->bucketnum;
ISC_LIST_UNLINK(res->buckets[bucketnum].fctxs, fctx, link);
LOCK(&res->nlock);
res->nfctx--;
UNLOCK(&res->nlock);
dec_stats(res, dns_resstatscounter_nfetch);
if (res->buckets[bucketnum].exiting &&
ISC_LIST_EMPTY(res->buckets[bucketnum].fctxs))
return (true);
return (false);
}
static void
fctx_destroy(fetchctx_t *fctx) {
isc_sockaddr_t *sa, *next_sa;
struct tried *tried;
REQUIRE(VALID_FCTX(fctx));
REQUIRE(fctx->state == fetchstate_done ||
fctx->state == fetchstate_init);
REQUIRE(ISC_LIST_EMPTY(fctx->events));
REQUIRE(ISC_LIST_EMPTY(fctx->queries));
REQUIRE(ISC_LIST_EMPTY(fctx->finds));
REQUIRE(ISC_LIST_EMPTY(fctx->altfinds));
REQUIRE(fctx->pending == 0);
REQUIRE(fctx->references == 0);
REQUIRE(ISC_LIST_EMPTY(fctx->validators));
REQUIRE(!ISC_LINK_LINKED(fctx, link));
FCTXTRACE("destroy");
/*
* Free bad.
*/
for (sa = ISC_LIST_HEAD(fctx->bad);
sa != NULL;
sa = next_sa) {
next_sa = ISC_LIST_NEXT(sa, link);
ISC_LIST_UNLINK(fctx->bad, sa, link);
isc_mem_put(fctx->mctx, sa, sizeof(*sa));
}
for (tried = ISC_LIST_HEAD(fctx->edns);
tried != NULL;
tried = ISC_LIST_HEAD(fctx->edns)) {
ISC_LIST_UNLINK(fctx->edns, tried, link);
isc_mem_put(fctx->mctx, tried, sizeof(*tried));
}
for (tried = ISC_LIST_HEAD(fctx->edns512);
tried != NULL;
tried = ISC_LIST_HEAD(fctx->edns512)) {
ISC_LIST_UNLINK(fctx->edns512, tried, link);
isc_mem_put(fctx->mctx, tried, sizeof(*tried));
}
for (sa = ISC_LIST_HEAD(fctx->bad_edns);
sa != NULL;
sa = next_sa) {
next_sa = ISC_LIST_NEXT(sa, link);
ISC_LIST_UNLINK(fctx->bad_edns, sa, link);
isc_mem_put(fctx->mctx, sa, sizeof(*sa));
}
isc_counter_detach(&fctx->qc);
fcount_decr(fctx);
isc_timer_detach(&fctx->timer);
dns_message_detach(&fctx->qmessage);
if (dns_name_countlabels(&fctx->domain) > 0)
dns_name_free(&fctx->domain, fctx->mctx);
if (dns_rdataset_isassociated(&fctx->nameservers))
dns_rdataset_disassociate(&fctx->nameservers);
dns_name_free(&fctx->name, fctx->mctx);
dns_db_detach(&fctx->cache);
dns_adb_detach(&fctx->adb);
isc_mem_free(fctx->mctx, fctx->info);
isc_mem_putanddetach(&fctx->mctx, fctx, sizeof(*fctx));
}
/*
* Fetch event handlers.
*/
static void
fctx_timeout(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx = event->ev_arg;
isc_timerevent_t *tevent = (isc_timerevent_t *)event;
resquery_t *query;
REQUIRE(VALID_FCTX(fctx));
UNUSED(task);
FCTXTRACE("timeout");
inc_stats(fctx->res, dns_resstatscounter_querytimeout);
if (event->ev_type == ISC_TIMEREVENT_LIFE) {
fctx->reason = NULL;
fctx_done(fctx, ISC_R_TIMEDOUT, __LINE__);
} else {
isc_result_t result;
fctx->timeouts++;
fctx->timeout = true;
/*
* We could cancel the running queries here, or we could let
* them keep going. Since we normally use separate sockets for
* different queries, we adopt the former approach to reduce
* the number of open sockets: cancel the oldest query if it
* expired after the query had started (this is usually the
* case but is not always so, depending on the task schedule
* timing).
*/
query = ISC_LIST_HEAD(fctx->queries);
if (query != NULL &&
isc_time_compare(&tevent->due, &query->start) >= 0)
{
FCTXTRACE("query timed out; no response");
fctx_cancelquery(&query, NULL, NULL, true, false);
}
FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT);
/*
* Our timer has triggered. Reestablish the fctx lifetime
* timer.
*/
result = fctx_starttimer(fctx);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result, __LINE__);
else
/*
* Keep trying.
*/
fctx_try(fctx, true, false);
}
isc_event_free(&event);
}
static void
fctx_shutdown(fetchctx_t *fctx) {
isc_event_t *cevent;
/*
* Start the shutdown process for fctx, if it isn't already underway.
*/
FCTXTRACE("shutdown");
/*
* The caller must be holding the appropriate bucket lock.
*/
if (fctx->want_shutdown)
return;
fctx->want_shutdown = true;
/*
* Unless we're still initializing (in which case the
* control event is still outstanding), we need to post
* the control event to tell the fetch we want it to
* exit.
*/
if (fctx->state != fetchstate_init) {
cevent = &fctx->control_event;
isc_task_send(fctx->res->buckets[fctx->bucketnum].task,
&cevent);
}
}
static void
fctx_doshutdown(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx = event->ev_arg;
bool bucket_empty = false;
dns_resolver_t *res;
unsigned int bucketnum;
dns_validator_t *validator;
bool dodestroy = false;
REQUIRE(VALID_FCTX(fctx));
UNUSED(task);
res = fctx->res;
bucketnum = fctx->bucketnum;
FCTXTRACE("doshutdown");
/*
* An fctx that is shutting down is no longer in ADDRWAIT mode.
*/
FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT);
/*
* Cancel all pending validators. Note that this must be done
* without the bucket lock held, since that could cause deadlock.
*/
validator = ISC_LIST_HEAD(fctx->validators);
while (validator != NULL) {
dns_validator_cancel(validator);
validator = ISC_LIST_NEXT(validator, link);
}
if (fctx->nsfetch != NULL)
dns_resolver_cancelfetch(fctx->nsfetch);
/*
* Shut down anything still running on behalf of this
* fetch, and clean up finds and addresses. To avoid deadlock
* with the ADB, we must do this before we lock the bucket lock.
*/
fctx_stopqueries(fctx, false, false);
fctx_cleanupall(fctx);
LOCK(&res->buckets[bucketnum].lock);
fctx->shuttingdown = true;
INSIST(fctx->state == fetchstate_active ||
fctx->state == fetchstate_done);
INSIST(fctx->want_shutdown);
if (fctx->state != fetchstate_done) {
fctx->state = fetchstate_done;
fctx_sendevents(fctx, ISC_R_CANCELED, __LINE__);
}
if (fctx->references == 0 && fctx->pending == 0 &&
fctx->nqueries == 0 && ISC_LIST_EMPTY(fctx->validators)) {
bucket_empty = fctx_unlink(fctx);
dodestroy = true;
}
UNLOCK(&res->buckets[bucketnum].lock);
if (dodestroy) {
fctx_destroy(fctx);
if (bucket_empty)
empty_bucket(res);
}
}
static void
fctx_start(isc_task_t *task, isc_event_t *event) {
fetchctx_t *fctx = event->ev_arg;
bool done = false, bucket_empty = false;
dns_resolver_t *res;
unsigned int bucketnum;
bool dodestroy = false;
REQUIRE(VALID_FCTX(fctx));
UNUSED(task);
res = fctx->res;
bucketnum = fctx->bucketnum;
FCTXTRACE("start");
LOCK(&res->buckets[bucketnum].lock);
INSIST(fctx->state == fetchstate_init);
if (fctx->want_shutdown) {
/*
* We haven't started this fctx yet, and we've been requested
* to shut it down.
*/
fctx->shuttingdown = true;
fctx->state = fetchstate_done;
fctx_sendevents(fctx, ISC_R_CANCELED, __LINE__);
/*
* Since we haven't started, we INSIST that we have no
* pending ADB finds and no pending validations.
*/
INSIST(fctx->pending == 0);
INSIST(fctx->nqueries == 0);
INSIST(ISC_LIST_EMPTY(fctx->validators));
if (fctx->references == 0) {
/*
* It's now safe to destroy this fctx.
*/
bucket_empty = fctx_unlink(fctx);
dodestroy = true;
}
done = true;
} else {
/*
* Normal fctx startup.
*/
fctx->state = fetchstate_active;
/*
* Reset the control event for later use in shutting down
* the fctx.
*/
ISC_EVENT_INIT(event, sizeof(*event), 0, NULL,
DNS_EVENT_FETCHCONTROL, fctx_doshutdown, fctx,
NULL, NULL, NULL);
}
UNLOCK(&res->buckets[bucketnum].lock);
if (!done) {
isc_result_t result;
INSIST(!dodestroy);
/*
* All is well. Start working on the fetch.
*/
result = fctx_starttimer(fctx);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result, __LINE__);
else
fctx_try(fctx, false, false);
} else if (dodestroy) {
fctx_destroy(fctx);
if (bucket_empty)
empty_bucket(res);
}
}
/*
* Fetch Creation, Joining, and Cancellation.
*/
static inline isc_result_t
fctx_join(fetchctx_t *fctx, isc_task_t *task, isc_sockaddr_t *client,
dns_messageid_t id, isc_taskaction_t action, void *arg,
dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
dns_fetch_t *fetch)
{
isc_task_t *tclone;
dns_fetchevent_t *event;
FCTXTRACE("join");
/*
* We store the task we're going to send this event to in the
* sender field. We'll make the fetch the sender when we actually
* send the event.
*/
tclone = NULL;
isc_task_attach(task, &tclone);
event = (dns_fetchevent_t *)
isc_event_allocate(fctx->res->mctx, tclone, DNS_EVENT_FETCHDONE,
action, arg, sizeof(*event));
if (event == NULL) {
isc_task_detach(&tclone);
return (ISC_R_NOMEMORY);
}
event->result = DNS_R_SERVFAIL;
event->qtype = fctx->type;
event->db = NULL;
event->node = NULL;
event->rdataset = rdataset;
event->sigrdataset = sigrdataset;
event->fetch = fetch;
event->client = client;
event->id = id;
dns_fixedname_init(&event->foundname);
/*
* Make sure that we can store the sigrdataset in the
* first event if it is needed by any of the events.
*/
if (event->sigrdataset != NULL)
ISC_LIST_PREPEND(fctx->events, event, ev_link);
else
ISC_LIST_APPEND(fctx->events, event, ev_link);
fctx->references++;
fetch->magic = DNS_FETCH_MAGIC;
fetch->private = fctx;
return (ISC_R_SUCCESS);
}
static inline void
log_ns_ttl(fetchctx_t *fctx, const char *where) {
char namebuf[DNS_NAME_FORMATSIZE];
char domainbuf[DNS_NAME_FORMATSIZE];
dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(10),
"log_ns_ttl: fctx %p: %s: %s (in '%s'?): %u %u",
fctx, where, namebuf, domainbuf,
fctx->ns_ttl_ok, fctx->ns_ttl);
}
static isc_result_t
fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type,
dns_name_t *domain, dns_rdataset_t *nameservers,
const isc_sockaddr_t *client, unsigned int options,
unsigned int bucketnum, unsigned int depth, isc_counter_t *qc,
fetchctx_t **fctxp)
{
fetchctx_t *fctx;
isc_result_t result;
isc_result_t iresult;
isc_interval_t interval;
dns_fixedname_t fixed;
unsigned int findoptions = 0;
char buf[DNS_NAME_FORMATSIZE + DNS_RDATATYPE_FORMATSIZE];
char typebuf[DNS_RDATATYPE_FORMATSIZE];
isc_mem_t *mctx;
/*
* Caller must be holding the lock for bucket number 'bucketnum'.
*/
REQUIRE(fctxp != NULL && *fctxp == NULL);
mctx = res->buckets[bucketnum].mctx;
fctx = isc_mem_get(mctx, sizeof(*fctx));
if (fctx == NULL)
return (ISC_R_NOMEMORY);
fctx->qc = NULL;
if (qc != NULL) {
isc_counter_attach(qc, &fctx->qc);
} else {
result = isc_counter_create(res->mctx,
res->maxqueries, &fctx->qc);
if (result != ISC_R_SUCCESS)
goto cleanup_fetch;
}
/*
* Make fctx->info point to a copy of a formatted string
* "name/type".
*/
dns_name_format(name, buf, sizeof(buf));
dns_rdatatype_format(type, typebuf, sizeof(typebuf));
strlcat(buf, "/", sizeof(buf));
strlcat(buf, typebuf, sizeof(buf));
fctx->info = isc_mem_strdup(mctx, buf);
if (fctx->info == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup_counter;
}
FCTXTRACE("create");
dns_name_init(&fctx->name, NULL);
result = dns_name_dup(name, mctx, &fctx->name);
if (result != ISC_R_SUCCESS)
goto cleanup_info;
dns_name_init(&fctx->domain, NULL);
dns_rdataset_init(&fctx->nameservers);
fctx->type = type;
fctx->options = options;
/*
* Note! We do not attach to the task. We are relying on the
* resolver to ensure that this task doesn't go away while we are
* using it.
*/
fctx->res = res;
fctx->references = 0;
fctx->bucketnum = bucketnum;
fctx->dbucketnum = RES_NOBUCKET;
fctx->state = fetchstate_init;
fctx->want_shutdown = false;
fctx->cloned = false;
fctx->depth = depth;
ISC_LIST_INIT(fctx->queries);
ISC_LIST_INIT(fctx->finds);
ISC_LIST_INIT(fctx->altfinds);
ISC_LIST_INIT(fctx->forwaddrs);
ISC_LIST_INIT(fctx->altaddrs);
ISC_LIST_INIT(fctx->forwarders);
fctx->fwdpolicy = dns_fwdpolicy_none;
ISC_LIST_INIT(fctx->bad);
ISC_LIST_INIT(fctx->edns);
ISC_LIST_INIT(fctx->edns512);
ISC_LIST_INIT(fctx->bad_edns);
ISC_LIST_INIT(fctx->validators);
fctx->validator = NULL;
fctx->find = NULL;
fctx->altfind = NULL;
fctx->pending = 0;
fctx->restarts = 0;
fctx->querysent = 0;
fctx->referrals = 0;
TIME_NOW(&fctx->start);
fctx->timeouts = 0;
fctx->lamecount = 0;
fctx->quotacount = 0;
fctx->adberr = 0;
fctx->neterr = 0;
fctx->badresp = 0;
fctx->findfail = 0;
fctx->valfail = 0;
fctx->result = ISC_R_FAILURE;
fctx->vresult = ISC_R_SUCCESS;
fctx->exitline = -1; /* sentinel */
fctx->logged = false;
fctx->attributes = 0;
fctx->spilled = false;
fctx->shuttingdown = false;
fctx->nqueries = 0;
fctx->reason = NULL;
fctx->rand_buf = 0;
fctx->rand_bits = 0;
fctx->timeout = false;
fctx->addrinfo = NULL;
if (client != NULL) {
isc_sockaddr_format(client, fctx->clientstr,
sizeof(fctx->clientstr));
} else {
strlcpy(fctx->clientstr, "<unknown>", sizeof(fctx->clientstr));
}
fctx->ns_ttl = 0;
fctx->ns_ttl_ok = false;
dns_name_init(&fctx->nsname, NULL);
fctx->nsfetch = NULL;
dns_rdataset_init(&fctx->nsrrset);
if (domain == NULL) {
dns_forwarders_t *forwarders = NULL;
unsigned int labels;
dns_name_t *fwdname = name;
dns_name_t suffix;
/*
* DS records are found in the parent server. Strip one
* leading label from the name (to be used in finding
* the forwarder).
*/
if (dns_rdatatype_atparent(fctx->type) &&
dns_name_countlabels(name) > 1) {
dns_name_init(&suffix, NULL);
labels = dns_name_countlabels(name);
dns_name_getlabelsequence(name, 1, labels - 1, &suffix);
fwdname = &suffix;
}
/* Find the forwarder for this name. */
domain = dns_fixedname_initname(&fixed);
result = dns_fwdtable_find2(fctx->res->view->fwdtable, fwdname,
domain, &forwarders);
if (result == ISC_R_SUCCESS)
fctx->fwdpolicy = forwarders->fwdpolicy;
if (fctx->fwdpolicy != dns_fwdpolicy_only) {
/*
* The caller didn't supply a query domain and
* nameservers, and we're not in forward-only mode,
* so find the best nameservers to use.
*/
if (dns_rdatatype_atparent(fctx->type))
findoptions |= DNS_DBFIND_NOEXACT;
result = dns_view_findzonecut(res->view, name,
domain, 0, findoptions,
true,
&fctx->nameservers,
NULL);
if (result != ISC_R_SUCCESS)
goto cleanup_nameservers;
result = dns_name_dup(domain, mctx, &fctx->domain);
if (result != ISC_R_SUCCESS)
goto cleanup_nameservers;
fctx->ns_ttl = fctx->nameservers.ttl;
fctx->ns_ttl_ok = true;
} else {
/*
* We're in forward-only mode. Set the query domain.
*/
result = dns_name_dup(domain, mctx, &fctx->domain);
if (result != ISC_R_SUCCESS)
goto cleanup_name;
}
} else {
result = dns_name_dup(domain, mctx, &fctx->domain);
if (result != ISC_R_SUCCESS)
goto cleanup_name;
dns_rdataset_clone(nameservers, &fctx->nameservers);
fctx->ns_ttl = fctx->nameservers.ttl;
fctx->ns_ttl_ok = true;
}
/*
* Are there too many simultaneous queries for this domain?
*/
result = fcount_incr(fctx, false);
if (result != ISC_R_SUCCESS) {
result = fctx->res->quotaresp[dns_quotatype_zone];
inc_stats(res, dns_resstatscounter_zonequota);
goto cleanup_domain;
}
log_ns_ttl(fctx, "fctx_create");
INSIST(dns_name_issubdomain(&fctx->name, &fctx->domain));
fctx->qmessage = NULL;
result = dns_message_create(mctx, DNS_MESSAGE_INTENTRENDER,
&fctx->qmessage);
if (result != ISC_R_SUCCESS)
goto cleanup_fcount;
/*
* Compute an expiration time for the entire fetch.
*/
isc_interval_set(&interval, res->query_timeout, 0);
iresult = isc_time_nowplusinterval(&fctx->expires, &interval);
if (iresult != ISC_R_SUCCESS) {
UNEXPECTED_ERROR(__FILE__, __LINE__,
"isc_time_nowplusinterval: %s",
isc_result_totext(iresult));
result = ISC_R_UNEXPECTED;
goto cleanup_qmessage;
}
/*
* Default retry interval initialization. We set the interval now
* mostly so it won't be uninitialized. It will be set to the
* correct value before a query is issued.
*/
isc_interval_set(&fctx->interval, 2, 0);
/*
* Create an inactive timer. It will be made active when the fetch
* is actually started.
*/
fctx->timer = NULL;
iresult = isc_timer_create(res->timermgr, isc_timertype_inactive,
NULL, NULL,
res->buckets[bucketnum].task, fctx_timeout,
fctx, &fctx->timer);
if (iresult != ISC_R_SUCCESS) {
UNEXPECTED_ERROR(__FILE__, __LINE__,
"isc_timer_create: %s",
isc_result_totext(iresult));
result = ISC_R_UNEXPECTED;
goto cleanup_qmessage;
}
/*
* Attach to the view's cache and adb.
*/
fctx->cache = NULL;
dns_db_attach(res->view->cachedb, &fctx->cache);
fctx->adb = NULL;
dns_adb_attach(res->view->adb, &fctx->adb);
fctx->mctx = NULL;
isc_mem_attach(mctx, &fctx->mctx);
ISC_LIST_INIT(fctx->events);
ISC_LINK_INIT(fctx, link);
fctx->magic = FCTX_MAGIC;
ISC_LIST_APPEND(res->buckets[bucketnum].fctxs, fctx, link);
LOCK(&res->nlock);
res->nfctx++;
UNLOCK(&res->nlock);
inc_stats(res, dns_resstatscounter_nfetch);
*fctxp = fctx;
return (ISC_R_SUCCESS);
cleanup_qmessage:
dns_message_detach(&fctx->qmessage);
cleanup_fcount:
fcount_decr(fctx);
cleanup_domain:
if (dns_name_countlabels(&fctx->domain) > 0)
dns_name_free(&fctx->domain, mctx);
cleanup_nameservers:
if (dns_rdataset_isassociated(&fctx->nameservers))
dns_rdataset_disassociate(&fctx->nameservers);
cleanup_name:
dns_name_free(&fctx->name, mctx);
cleanup_info:
isc_mem_free(mctx, fctx->info);
cleanup_counter:
isc_counter_detach(&fctx->qc);
cleanup_fetch:
isc_mem_put(mctx, fctx, sizeof(*fctx));
return (result);
}
/*
* Handle Responses
*/
static inline bool
is_lame(fetchctx_t *fctx, dns_message_t *message) {
dns_name_t *name;
dns_rdataset_t *rdataset;
isc_result_t result;
if (message->rcode != dns_rcode_noerror &&
message->rcode != dns_rcode_yxdomain &&
message->rcode != dns_rcode_nxdomain)
return (false);
if (message->counts[DNS_SECTION_ANSWER] != 0)
return (false);
if (message->counts[DNS_SECTION_AUTHORITY] == 0)
return (false);
result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
dns_namereln_t namereln;
int order;
unsigned int labels;
if (rdataset->type != dns_rdatatype_ns)
continue;
namereln = dns_name_fullcompare(name, &fctx->domain,
&order, &labels);
if (namereln == dns_namereln_equal &&
(message->flags & DNS_MESSAGEFLAG_AA) != 0)
return (false);
if (namereln == dns_namereln_subdomain)
return (false);
return (true);
}
result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
}
return (false);
}
static inline void
log_lame(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo) {
char namebuf[DNS_NAME_FORMATSIZE];
char domainbuf[DNS_NAME_FORMATSIZE];
char addrbuf[ISC_SOCKADDR_FORMATSIZE];
dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
isc_sockaddr_format(&addrinfo->sockaddr, addrbuf, sizeof(addrbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"lame server resolving '%s' (in '%s'?): %s",
namebuf, domainbuf, addrbuf);
}
static inline void
log_formerr(fetchctx_t *fctx, const char *format, ...) {
char nsbuf[ISC_SOCKADDR_FORMATSIZE];
char msgbuf[2048];
va_list args;
va_start(args, format);
vsnprintf(msgbuf, sizeof(msgbuf), format, args);
va_end(args);
isc_sockaddr_format(&fctx->addrinfo->sockaddr, nsbuf, sizeof(nsbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
"DNS format error from %s resolving %s for %s: %s",
nsbuf, fctx->info, fctx->clientstr, msgbuf);
}
static isc_result_t
same_question(fetchctx_t *fctx, dns_message_t *message) {
isc_result_t result;
dns_name_t *name;
dns_rdataset_t *rdataset;
/*
* Caller must be holding the fctx lock.
*/
/*
* XXXRTH Currently we support only one question.
*/
if (ISC_UNLIKELY(message->counts[DNS_SECTION_QUESTION] == 0)) {
if ((message->flags & DNS_MESSAGEFLAG_TC) != 0) {
/*
* If TC=1 and the question section is empty, we
* accept the reply message as a truncated
* answer, to be retried over TCP.
*
* It is really a FORMERR condition, but this is
* a workaround to accept replies from some
* implementations.
*
* Because the question section matching is not
* performed, the worst that could happen is
* that an attacker who gets past the ID and
* source port checks can force the use of
* TCP. This is considered an acceptable risk.
*/
log_formerr(fctx,
"empty question section, "
"accepting it anyway as TC=1");
return (ISC_R_SUCCESS);
} else {
log_formerr(fctx, "empty question section");
return (DNS_R_FORMERR);
}
} else if (ISC_UNLIKELY(message->counts[DNS_SECTION_QUESTION] > 1)) {
log_formerr(fctx, "too many questions");
return (DNS_R_FORMERR);
}
result = dns_message_firstname(message, DNS_SECTION_QUESTION);
if (result != ISC_R_SUCCESS)
return (result);
name = NULL;
dns_message_currentname(message, DNS_SECTION_QUESTION, &name);
rdataset = ISC_LIST_HEAD(name->list);
INSIST(rdataset != NULL);
INSIST(ISC_LIST_NEXT(rdataset, link) == NULL);
if (fctx->type != rdataset->type ||
fctx->res->rdclass != rdataset->rdclass ||
!dns_name_equal(&fctx->name, name)) {
char namebuf[DNS_NAME_FORMATSIZE];
char classbuf[DNS_RDATACLASS_FORMATSIZE];
char typebuf[DNS_RDATATYPE_FORMATSIZE];
dns_name_format(name, namebuf, sizeof(namebuf));
dns_rdataclass_format(rdataset->rdclass, classbuf,
sizeof(classbuf));
dns_rdatatype_format(rdataset->type, typebuf, sizeof(typebuf));
log_formerr(fctx, "question section mismatch: got %s/%s/%s",
namebuf, classbuf, typebuf);
return (DNS_R_FORMERR);
}
return (ISC_R_SUCCESS);
}
static void
clone_results(fetchctx_t *fctx) {
dns_fetchevent_t *event, *hevent;
isc_result_t result;
dns_name_t *name, *hname;
FCTXTRACE("clone_results");
/*
* Set up any other events to have the same data as the first
* event.
*
* Caller must be holding the appropriate lock.
*/
fctx->cloned = true;
hevent = ISC_LIST_HEAD(fctx->events);
if (hevent == NULL)
return;
hname = dns_fixedname_name(&hevent->foundname);
for (event = ISC_LIST_NEXT(hevent, ev_link);
event != NULL;
event = ISC_LIST_NEXT(event, ev_link)) {
name = dns_fixedname_name(&event->foundname);
result = dns_name_copy(hname, name, NULL);
if (result != ISC_R_SUCCESS)
event->result = result;
else
event->result = hevent->result;
dns_db_attach(hevent->db, &event->db);
dns_db_attachnode(hevent->db, hevent->node, &event->node);
INSIST(hevent->rdataset != NULL);
INSIST(event->rdataset != NULL);
if (dns_rdataset_isassociated(hevent->rdataset))
dns_rdataset_clone(hevent->rdataset, event->rdataset);
INSIST(! (hevent->sigrdataset == NULL &&
event->sigrdataset != NULL));
if (hevent->sigrdataset != NULL &&
dns_rdataset_isassociated(hevent->sigrdataset) &&
event->sigrdataset != NULL)
dns_rdataset_clone(hevent->sigrdataset,
event->sigrdataset);
}
}
#define CACHE(r) (((r)->attributes & DNS_RDATASETATTR_CACHE) != 0)
#define ANSWER(r) (((r)->attributes & DNS_RDATASETATTR_ANSWER) != 0)
#define ANSWERSIG(r) (((r)->attributes & DNS_RDATASETATTR_ANSWERSIG) != 0)
#define EXTERNAL(r) (((r)->attributes & DNS_RDATASETATTR_EXTERNAL) != 0)
#define CHAINING(r) (((r)->attributes & DNS_RDATASETATTR_CHAINING) != 0)
#define CHASE(r) (((r)->attributes & DNS_RDATASETATTR_CHASE) != 0)
#define CHECKNAMES(r) (((r)->attributes & DNS_RDATASETATTR_CHECKNAMES) != 0)
/*
* Destroy '*fctx' if it is ready to be destroyed (i.e., if it has
* no references and is no longer waiting for any events).
*
* Requires:
* '*fctx' is shutting down.
*
* Returns:
* true if the resolver is exiting and this is the last fctx in the bucket.
*/
static bool
maybe_destroy(fetchctx_t *fctx, bool locked) {
unsigned int bucketnum;
bool bucket_empty = false;
dns_resolver_t *res = fctx->res;
dns_validator_t *validator, *next_validator;
bool dodestroy = false;
bucketnum = fctx->bucketnum;
if (!locked)
LOCK(&res->buckets[bucketnum].lock);
REQUIRE(fctx->shuttingdown);
if (fctx->pending != 0 || fctx->nqueries != 0)
goto unlock;
for (validator = ISC_LIST_HEAD(fctx->validators);
validator != NULL; validator = next_validator) {
next_validator = ISC_LIST_NEXT(validator, link);
dns_validator_cancel(validator);
}
if (fctx->references == 0 && ISC_LIST_EMPTY(fctx->validators)) {
bucket_empty = fctx_unlink(fctx);
dodestroy = true;
}
unlock:
if (!locked)
UNLOCK(&res->buckets[bucketnum].lock);
if (dodestroy)
fctx_destroy(fctx);
return (bucket_empty);
}
/*
* The validator has finished.
*/
static void
validated(isc_task_t *task, isc_event_t *event) {
dns_adbaddrinfo_t *addrinfo;
dns_dbnode_t *node = NULL;
dns_dbnode_t *nsnode = NULL;
dns_fetchevent_t *hevent;
dns_name_t *name;
dns_rdataset_t *ardataset = NULL;
dns_rdataset_t *asigrdataset = NULL;
dns_rdataset_t *rdataset;
dns_rdataset_t *sigrdataset;
dns_resolver_t *res;
dns_valarg_t *valarg;
dns_validatorevent_t *vevent;
fetchctx_t *fctx;
bool chaining;
bool negative;
bool sentresponse;
isc_result_t eresult = ISC_R_SUCCESS;
isc_result_t result = ISC_R_SUCCESS;
isc_stdtime_t now;
uint32_t ttl;
unsigned options;
uint32_t bucketnum;
dns_message_t *rmessage = NULL;
UNUSED(task); /* for now */
REQUIRE(event->ev_type == DNS_EVENT_VALIDATORDONE);
valarg = event->ev_arg;
fctx = valarg->fctx;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
addrinfo = valarg->addrinfo;
REQUIRE(!ISC_LIST_EMPTY(fctx->validators));
dns_message_attach(valarg->rmessage, &rmessage);
vevent = (dns_validatorevent_t *)event;
fctx->vresult = vevent->result;
FCTXTRACE("received validation completion event");
bucketnum = fctx->bucketnum;
LOCK(&res->buckets[bucketnum].lock);
ISC_LIST_UNLINK(fctx->validators, vevent->validator, link);
fctx->validator = NULL;
UNLOCK(&res->buckets[bucketnum].lock);
/*
* Destroy the validator early so that we can
* destroy the fctx if necessary.
*/
dns_validator_destroy(&vevent->validator);
dns_message_detach(&valarg->rmessage);
isc_mem_put(fctx->mctx, valarg, sizeof(*valarg));
negative = (vevent->rdataset == NULL);
LOCK(&res->buckets[bucketnum].lock);
sentresponse = ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0);
/*
* If shutting down, ignore the results. Check to see if we're
* done waiting for validator completions and ADB pending events; if
* so, destroy the fctx.
*/
if (fctx->shuttingdown && !sentresponse) {
bool bucket_empty;
bucket_empty = maybe_destroy(fctx, true);
UNLOCK(&res->buckets[bucketnum].lock);
if (bucket_empty)
empty_bucket(res);
goto cleanup_event;
}
isc_stdtime_get(&now);
/*
* If chaining, we need to make sure that the right result code is
* returned, and that the rdatasets are bound.
*/
if (vevent->result == ISC_R_SUCCESS &&
!negative &&
vevent->rdataset != NULL &&
CHAINING(vevent->rdataset))
{
if (vevent->rdataset->type == dns_rdatatype_cname)
eresult = DNS_R_CNAME;
else {
INSIST(vevent->rdataset->type == dns_rdatatype_dname);
eresult = DNS_R_DNAME;
}
chaining = true;
} else
chaining = false;
/*
* Either we're not shutting down, or we are shutting down but want
* to cache the result anyway (if this was a validation started by
* a query with cd set)
*/
hevent = ISC_LIST_HEAD(fctx->events);
if (hevent != NULL) {
if (!negative && !chaining &&
(fctx->type == dns_rdatatype_any ||
fctx->type == dns_rdatatype_rrsig ||
fctx->type == dns_rdatatype_sig)) {
/*
* Don't bind rdatasets; the caller
* will iterate the node.
*/
} else {
ardataset = hevent->rdataset;
asigrdataset = hevent->sigrdataset;
}
}
if (vevent->result != ISC_R_SUCCESS) {
FCTXTRACE("validation failed");
inc_stats(res, dns_resstatscounter_valfail);
fctx->valfail++;
fctx->vresult = vevent->result;
if (fctx->vresult != DNS_R_BROKENCHAIN) {
result = ISC_R_NOTFOUND;
if (vevent->rdataset != NULL)
result = dns_db_findnode(fctx->cache,
vevent->name,
true, &node);
if (result == ISC_R_SUCCESS)
(void)dns_db_deleterdataset(fctx->cache, node,
NULL,
vevent->type, 0);
if (result == ISC_R_SUCCESS &&
vevent->sigrdataset != NULL)
(void)dns_db_deleterdataset(fctx->cache, node,
NULL,
dns_rdatatype_rrsig,
vevent->type);
if (result == ISC_R_SUCCESS)
dns_db_detachnode(fctx->cache, &node);
}
if (fctx->vresult == DNS_R_BROKENCHAIN && !negative) {
/*
* Cache the data as pending for later validation.
*/
result = ISC_R_NOTFOUND;
if (vevent->rdataset != NULL)
result = dns_db_findnode(fctx->cache,
vevent->name,
true, &node);
if (result == ISC_R_SUCCESS) {
(void)dns_db_addrdataset(fctx->cache, node,
NULL, now,
vevent->rdataset, 0,
NULL);
}
if (result == ISC_R_SUCCESS &&
vevent->sigrdataset != NULL)
(void)dns_db_addrdataset(fctx->cache, node,
NULL, now,
vevent->sigrdataset,
0, NULL);
if (result == ISC_R_SUCCESS)
dns_db_detachnode(fctx->cache, &node);
}
result = fctx->vresult;
add_bad(fctx, rmessage, addrinfo, result,
badns_validation);
isc_event_free(&event);
UNLOCK(&res->buckets[bucketnum].lock);
INSIST(fctx->validator == NULL);
fctx->validator = ISC_LIST_HEAD(fctx->validators);
if (fctx->validator != NULL)
dns_validator_send(fctx->validator);
else if (sentresponse)
fctx_done(fctx, result, __LINE__); /* Locks bucket. */
else if (result == DNS_R_BROKENCHAIN) {
isc_result_t tresult;
isc_time_t expire;
isc_interval_t i;
isc_interval_set(&i, DNS_RESOLVER_BADCACHETTL(fctx), 0);
tresult = isc_time_nowplusinterval(&expire, &i);
if (negative &&
(fctx->type == dns_rdatatype_dnskey ||
fctx->type == dns_rdatatype_dlv ||
fctx->type == dns_rdatatype_ds) &&
tresult == ISC_R_SUCCESS)
dns_resolver_addbadcache(res, &fctx->name,
fctx->type, &expire);
fctx_done(fctx, result, __LINE__); /* Locks bucket. */
} else {
fctx_try(fctx, true, true); /* Locks bucket. */
}
goto cleanup_rmessage;
}
if (negative) {
dns_rdatatype_t covers;
FCTXTRACE("nonexistence validation OK");
inc_stats(res, dns_resstatscounter_valnegsuccess);
/*
* Cache DS NXDOMAIN separately to other types.
*/
if (rmessage->rcode == dns_rcode_nxdomain &&
fctx->type != dns_rdatatype_ds)
covers = dns_rdatatype_any;
else
covers = fctx->type;
result = dns_db_findnode(fctx->cache, vevent->name, true,
&node);
if (result != ISC_R_SUCCESS)
goto noanswer_response;
/*
* If we are asking for a SOA record set the cache time
* to zero to facilitate locating the containing zone of
* a arbitrary zone.
*/
ttl = res->view->maxncachettl;
if (fctx->type == dns_rdatatype_soa &&
covers == dns_rdatatype_any && res->zero_no_soa_ttl)
ttl = 0;
result = ncache_adderesult(rmessage, fctx->cache, node,
covers, now, ttl, vevent->optout,
vevent->secure, ardataset, &eresult);
if (result != ISC_R_SUCCESS)
goto noanswer_response;
goto answer_response;
} else
inc_stats(res, dns_resstatscounter_valsuccess);
FCTXTRACE("validation OK");
if (vevent->proofs[DNS_VALIDATOR_NOQNAMEPROOF] != NULL) {
result = dns_rdataset_addnoqname(vevent->rdataset,
vevent->proofs[DNS_VALIDATOR_NOQNAMEPROOF]);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
INSIST(vevent->sigrdataset != NULL);
vevent->sigrdataset->ttl = vevent->rdataset->ttl;
if (vevent->proofs[DNS_VALIDATOR_CLOSESTENCLOSER] != NULL) {
result = dns_rdataset_addclosest(vevent->rdataset,
vevent->proofs[DNS_VALIDATOR_CLOSESTENCLOSER]);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
}
} else if (vevent->rdataset->trust == dns_trust_answer &&
vevent->rdataset->type != dns_rdatatype_rrsig)
{
isc_result_t tresult;
dns_name_t *noqname = NULL;
tresult = findnoqname(fctx, rmessage, vevent->name,
vevent->rdataset->type, &noqname);
if (tresult == ISC_R_SUCCESS && noqname != NULL) {
tresult = dns_rdataset_addnoqname(vevent->rdataset,
noqname);
RUNTIME_CHECK(tresult == ISC_R_SUCCESS);
}
}
/*
* The data was already cached as pending data.
* Re-cache it as secure and bind the cached
* rdatasets to the first event on the fetch
* event list.
*/
result = dns_db_findnode(fctx->cache, vevent->name, true, &node);
if (result != ISC_R_SUCCESS)
goto noanswer_response;
options = 0;
if ((fctx->options & DNS_FETCHOPT_PREFETCH) != 0)
options = DNS_DBADD_PREFETCH;
result = dns_db_addrdataset(fctx->cache, node, NULL, now,
vevent->rdataset, options, ardataset);
if (result != ISC_R_SUCCESS &&
result != DNS_R_UNCHANGED)
goto noanswer_response;
if (ardataset != NULL && NEGATIVE(ardataset)) {
if (NXDOMAIN(ardataset))
eresult = DNS_R_NCACHENXDOMAIN;
else
eresult = DNS_R_NCACHENXRRSET;
} else if (vevent->sigrdataset != NULL) {
result = dns_db_addrdataset(fctx->cache, node, NULL, now,
vevent->sigrdataset, options,
asigrdataset);
if (result != ISC_R_SUCCESS &&
result != DNS_R_UNCHANGED)
goto noanswer_response;
}
if (sentresponse) {
bool bucket_empty = false;
/*
* If we only deferred the destroy because we wanted to cache
* the data, destroy now.
*/
dns_db_detachnode(fctx->cache, &node);
if (fctx->shuttingdown) {
bucket_empty = maybe_destroy(fctx, true);
}
UNLOCK(&res->buckets[bucketnum].lock);
if (bucket_empty) {
empty_bucket(res);
}
goto cleanup_event;
}
if (!ISC_LIST_EMPTY(fctx->validators)) {
INSIST(!negative);
INSIST(fctx->type == dns_rdatatype_any ||
fctx->type == dns_rdatatype_rrsig ||
fctx->type == dns_rdatatype_sig);
/*
* Don't send a response yet - we have
* more rdatasets that still need to
* be validated.
*/
dns_db_detachnode(fctx->cache, &node);
UNLOCK(&res->buckets[bucketnum].lock);
dns_validator_send(ISC_LIST_HEAD(fctx->validators));
goto cleanup_event;
}
answer_response:
/*
* Cache any NS/NSEC records that happened to be validated.
*/
result = dns_message_firstname(rmessage, DNS_SECTION_AUTHORITY);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(rmessage, DNS_SECTION_AUTHORITY,
&name);
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
if ((rdataset->type != dns_rdatatype_ns &&
rdataset->type != dns_rdatatype_nsec) ||
rdataset->trust != dns_trust_secure)
continue;
for (sigrdataset = ISC_LIST_HEAD(name->list);
sigrdataset != NULL;
sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
if (sigrdataset->type != dns_rdatatype_rrsig ||
sigrdataset->covers != rdataset->type)
continue;
break;
}
if (sigrdataset == NULL ||
sigrdataset->trust != dns_trust_secure)
continue;
result = dns_db_findnode(fctx->cache, name, true,
&nsnode);
if (result != ISC_R_SUCCESS)
continue;
result = dns_db_addrdataset(fctx->cache, nsnode, NULL,
now, rdataset, 0, NULL);
if (result == ISC_R_SUCCESS)
result = dns_db_addrdataset(fctx->cache, nsnode,
NULL, now,
sigrdataset, 0,
NULL);
dns_db_detachnode(fctx->cache, &nsnode);
if (result != ISC_R_SUCCESS)
continue;
}
result = dns_message_nextname(rmessage,
DNS_SECTION_AUTHORITY);
}
result = ISC_R_SUCCESS;
/*
* Respond with an answer, positive or negative,
* as opposed to an error. 'node' must be non-NULL.
*/
FCTX_ATTR_SET(fctx, FCTX_ATTR_HAVEANSWER);
if (hevent != NULL) {
/*
* Negative results must be indicated in event->result.
*/
INSIST(hevent->rdataset != NULL);
if (dns_rdataset_isassociated(hevent->rdataset) &&
NEGATIVE(hevent->rdataset)) {
INSIST(eresult == DNS_R_NCACHENXDOMAIN ||
eresult == DNS_R_NCACHENXRRSET);
}
hevent->result = eresult;
RUNTIME_CHECK(dns_name_copy(vevent->name,
dns_fixedname_name(&hevent->foundname), NULL)
== ISC_R_SUCCESS);
dns_db_attach(fctx->cache, &hevent->db);
dns_db_transfernode(fctx->cache, &node, &hevent->node);
clone_results(fctx);
}
noanswer_response:
if (node != NULL)
dns_db_detachnode(fctx->cache, &node);
UNLOCK(&res->buckets[bucketnum].lock);
fctx_done(fctx, result, __LINE__); /* Locks bucket. */
cleanup_event:
INSIST(node == NULL);
isc_event_free(&event);
cleanup_rmessage:
dns_message_detach(&rmessage);
}
static void
fctx_log(void *arg, int level, const char *fmt, ...) {
char msgbuf[2048];
va_list args;
fetchctx_t *fctx = arg;
va_start(args, fmt);
vsnprintf(msgbuf, sizeof(msgbuf), fmt, args);
va_end(args);
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, level,
"fctx %p(%s): %s", fctx, fctx->info, msgbuf);
}
static inline isc_result_t
findnoqname(fetchctx_t *fctx, dns_message_t *rmessage,
dns_name_t *name, dns_rdatatype_t type,
dns_name_t **noqnamep)
{
dns_rdataset_t *nrdataset, *next, *sigrdataset;
dns_rdata_rrsig_t rrsig;
isc_result_t result;
unsigned int labels;
dns_section_t section;
dns_name_t *zonename;
dns_fixedname_t fzonename;
dns_name_t *closest;
dns_fixedname_t fclosest;
dns_name_t *nearest;
dns_fixedname_t fnearest;
dns_rdatatype_t found = dns_rdatatype_none;
dns_name_t *noqname = NULL;
FCTXTRACE("findnoqname");
REQUIRE(noqnamep != NULL && *noqnamep == NULL);
/*
* Find the SIG for this rdataset, if we have it.
*/
for (sigrdataset = ISC_LIST_HEAD(name->list);
sigrdataset != NULL;
sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
if (sigrdataset->type == dns_rdatatype_rrsig &&
sigrdataset->covers == type)
break;
}
if (sigrdataset == NULL)
return (ISC_R_NOTFOUND);
labels = dns_name_countlabels(name);
for (result = dns_rdataset_first(sigrdataset);
result == ISC_R_SUCCESS;
result = dns_rdataset_next(sigrdataset)) {
dns_rdata_t rdata = DNS_RDATA_INIT;
dns_rdataset_current(sigrdataset, &rdata);
result = dns_rdata_tostruct(&rdata, &rrsig, NULL);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
/* Wildcard has rrsig.labels < labels - 1. */
if (rrsig.labels + 1U >= labels)
continue;
break;
}
if (result == ISC_R_NOMORE)
return (ISC_R_NOTFOUND);
if (result != ISC_R_SUCCESS)
return (result);
zonename = dns_fixedname_initname(&fzonename);
closest = dns_fixedname_initname(&fclosest);
nearest = dns_fixedname_initname(&fnearest);
#define NXND(x) ((x) == ISC_R_SUCCESS)
section = DNS_SECTION_AUTHORITY;
for (result = dns_message_firstname(rmessage, section);
result == ISC_R_SUCCESS;
result = dns_message_nextname(rmessage, section)) {
dns_name_t *nsec = NULL;
dns_message_currentname(rmessage, section, &nsec);
for (nrdataset = ISC_LIST_HEAD(nsec->list);
nrdataset != NULL; nrdataset = next) {
bool data = false, exists = false;
bool optout = false, unknown = false;
bool setclosest = false;
bool setnearest = false;
next = ISC_LIST_NEXT(nrdataset, link);
if (nrdataset->type != dns_rdatatype_nsec &&
nrdataset->type != dns_rdatatype_nsec3)
continue;
if (nrdataset->type == dns_rdatatype_nsec &&
NXND(dns_nsec_noexistnodata(type, name, nsec,
nrdataset, &exists,
&data, NULL, fctx_log,
fctx)))
{
if (!exists) {
noqname = nsec;
found = dns_rdatatype_nsec;
}
}
if (nrdataset->type == dns_rdatatype_nsec3 &&
NXND(dns_nsec3_noexistnodata(type, name, nsec,
nrdataset, zonename,
&exists, &data,
&optout, &unknown,
&setclosest,
&setnearest,
closest, nearest,
fctx_log, fctx)))
{
if (!exists && setnearest) {
noqname = nsec;
found = dns_rdatatype_nsec3;
}
}
}
}
if (result == ISC_R_NOMORE)
result = ISC_R_SUCCESS;
if (noqname != NULL) {
for (sigrdataset = ISC_LIST_HEAD(noqname->list);
sigrdataset != NULL;
sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
if (sigrdataset->type == dns_rdatatype_rrsig &&
sigrdataset->covers == found)
break;
}
if (sigrdataset != NULL)
*noqnamep = noqname;
}
return (result);
}
static inline isc_result_t
cache_name(fetchctx_t *fctx, dns_message_t *rmessage,
dns_name_t *name, dns_adbaddrinfo_t *addrinfo,
isc_stdtime_t now)
{
dns_rdataset_t *rdataset = NULL, *sigrdataset = NULL;
dns_rdataset_t *addedrdataset = NULL;
dns_rdataset_t *ardataset = NULL, *asigrdataset = NULL;
dns_rdataset_t *valrdataset = NULL, *valsigrdataset = NULL;
dns_dbnode_t *node = NULL, **anodep = NULL;
dns_db_t **adbp = NULL;
dns_name_t *aname = NULL;
dns_resolver_t *res = fctx->res;
bool need_validation = false;
bool secure_domain = false;
bool have_answer = false;
isc_result_t result, eresult = ISC_R_SUCCESS;
dns_fetchevent_t *event = NULL;
unsigned int options;
isc_task_t *task;
bool fail;
unsigned int valoptions = 0;
bool checknta = true;
/*
* The appropriate bucket lock must be held.
*/
task = res->buckets[fctx->bucketnum].task;
/*
* Is DNSSEC validation required for this name?
*/
if (NONTA(fctx->options)) {
valoptions |= DNS_VALIDATOR_NONTA;
checknta = false;
}
if (res->view->enablevalidation) {
result = issecuredomain(res->view, name, fctx->type,
now, checknta, NULL, &secure_domain);
if (result != ISC_R_SUCCESS) {
return (result);
}
if (!secure_domain && res->view->dlv != NULL) {
valoptions |= DNS_VALIDATOR_DLV;
secure_domain = true;
}
}
if ((fctx->options & DNS_FETCHOPT_NOCDFLAG) != 0) {
valoptions |= DNS_VALIDATOR_NOCDFLAG;
}
if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0) {
need_validation = false;
} else {
need_validation = secure_domain;
}
if (((name->attributes & DNS_NAMEATTR_ANSWER) != 0) &&
(!need_validation))
{
have_answer = true;
event = ISC_LIST_HEAD(fctx->events);
if (event != NULL) {
adbp = &event->db;
aname = dns_fixedname_name(&event->foundname);
result = dns_name_copy(name, aname, NULL);
if (result != ISC_R_SUCCESS) {
return (result);
}
anodep = &event->node;
/*
* If this is an ANY, SIG or RRSIG query, we're not
* going to return any rdatasets, unless we encountered
* a CNAME or DNAME as "the answer". In this case,
* we're going to return DNS_R_CNAME or DNS_R_DNAME
* and we must set up the rdatasets.
*/
if ((fctx->type != dns_rdatatype_any &&
fctx->type != dns_rdatatype_rrsig &&
fctx->type != dns_rdatatype_sig) ||
(name->attributes & DNS_NAMEATTR_CHAINING) != 0)
{
ardataset = event->rdataset;
asigrdataset = event->sigrdataset;
}
}
}
/*
* Find or create the cache node.
*/
node = NULL;
result = dns_db_findnode(fctx->cache, name, true, &node);
if (result != ISC_R_SUCCESS) {
return (result);
}
/*
* Cache or validate each cacheable rdataset.
*/
fail = ((fctx->res->options & DNS_RESOLVER_CHECKNAMESFAIL) != 0);
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link))
{
if (!CACHE(rdataset)) {
continue;
}
if (CHECKNAMES(rdataset)) {
char namebuf[DNS_NAME_FORMATSIZE];
char typebuf[DNS_RDATATYPE_FORMATSIZE];
char classbuf[DNS_RDATATYPE_FORMATSIZE];
dns_name_format(name, namebuf, sizeof(namebuf));
dns_rdatatype_format(rdataset->type, typebuf,
sizeof(typebuf));
dns_rdataclass_format(rdataset->rdclass, classbuf,
sizeof(classbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
"check-names %s %s/%s/%s",
fail ? "failure" : "warning",
namebuf, typebuf, classbuf);
if (fail) {
if (ANSWER(rdataset)) {
dns_db_detachnode(fctx->cache, &node);
return (DNS_R_BADNAME);
}
continue;
}
}
/*
* Enforce the configure maximum cache TTL.
*/
if (rdataset->ttl > res->view->maxcachettl) {
rdataset->ttl = res->view->maxcachettl;
}
/*
* Mark the rdataset as being prefetch eligible.
*/
if (rdataset->ttl > fctx->res->view->prefetch_eligible) {
rdataset->attributes |= DNS_RDATASETATTR_PREFETCH;
}
/*
* Find the SIG for this rdataset, if we have it.
*/
for (sigrdataset = ISC_LIST_HEAD(name->list);
sigrdataset != NULL;
sigrdataset = ISC_LIST_NEXT(sigrdataset, link))
{
if (sigrdataset->type == dns_rdatatype_rrsig &&
sigrdataset->covers == rdataset->type)
{
break;
}
}
/*
* If this RRset is in a secure domain, is in bailiwick,
* and is not glue, attempt DNSSEC validation. (We do not
* attempt to validate glue or out-of-bailiwick data--even
* though there might be some performance benefit to doing
* so--because it makes it simpler and safer to ensure that
* records from a secure domain are only cached if validated
* within the context of a query to the domain that owns
* them.)
*/
if (secure_domain && rdataset->trust != dns_trust_glue &&
!EXTERNAL(rdataset))
{
dns_trust_t trust;
/*
* RRSIGs are validated as part of validating the
* type they cover.
*/
if (rdataset->type == dns_rdatatype_rrsig) {
continue;
}
if (sigrdataset == NULL && need_validation &&
!ANSWER(rdataset))
{
/*
* Ignore unrelated non-answer
* rdatasets that are missing signatures.
*/
continue;
}
/*
* Normalize the rdataset and sigrdataset TTLs.
*/
if (sigrdataset != NULL) {
rdataset->ttl = ISC_MIN(rdataset->ttl,
sigrdataset->ttl);
sigrdataset->ttl = rdataset->ttl;
}
/*
* Mark the rdataset as being prefetch eligible.
*/
if (rdataset->ttl > fctx->res->view->prefetch_eligible)
{
rdataset->attributes |=
DNS_RDATASETATTR_PREFETCH;
}
/*
* Cache this rdataset/sigrdataset pair as
* pending data. Track whether it was additional
* or not. If this was a priming query, additional
* should be cached as glue.
*/
if (rdataset->trust == dns_trust_additional) {
trust = dns_trust_pending_additional;
} else {
trust = dns_trust_pending_answer;
}
rdataset->trust = trust;
if (sigrdataset != NULL) {
sigrdataset->trust = trust;
}
if (!need_validation || !ANSWER(rdataset)) {
options = 0;
if (ANSWER(rdataset) &&
rdataset->type != dns_rdatatype_rrsig)
{
isc_result_t tresult;
dns_name_t *noqname = NULL;
tresult = findnoqname(fctx, rmessage,
name,
rdataset->type,
&noqname);
if (tresult == ISC_R_SUCCESS &&
noqname != NULL)
{
(void) dns_rdataset_addnoqname(
rdataset, noqname);
}
}
if ((fctx->options &
DNS_FETCHOPT_PREFETCH) != 0)
{
options = DNS_DBADD_PREFETCH;
}
if ((fctx->options &
DNS_FETCHOPT_NOCACHED) != 0)
{
options |= DNS_DBADD_FORCE;
}
addedrdataset = ardataset;
result = dns_db_addrdataset(fctx->cache, node,
NULL, now, rdataset,
options,
addedrdataset);
if (result == DNS_R_UNCHANGED) {
result = ISC_R_SUCCESS;
if (!need_validation &&
ardataset != NULL &&
NEGATIVE(ardataset))
{
/*
* The answer in the cache is
* better than the answer we
* found, and is a negative
* cache entry, so we must set
* eresult appropriately.
*/
if (NXDOMAIN(ardataset)) {
eresult =
DNS_R_NCACHENXDOMAIN;
} else {
eresult =
DNS_R_NCACHENXRRSET;
}
/*
* We have a negative response
* from the cache so don't
* attempt to add the RRSIG
* rrset.
*/
continue;
}
}
if (result != ISC_R_SUCCESS) {
break;
}
if (sigrdataset != NULL) {
addedrdataset = asigrdataset;
result = dns_db_addrdataset(fctx->cache,
node, NULL, now,
sigrdataset,
options,
addedrdataset);
if (result == DNS_R_UNCHANGED) {
result = ISC_R_SUCCESS;
}
if (result != ISC_R_SUCCESS) {
break;
}
} else if (!ANSWER(rdataset)) {
continue;
}
}
if (ANSWER(rdataset) && need_validation) {
if (fctx->type != dns_rdatatype_any &&
fctx->type != dns_rdatatype_rrsig &&
fctx->type != dns_rdatatype_sig)
{
/*
* This is The Answer. We will
* validate it, but first we cache
* the rest of the response - it may
* contain useful keys.
*/
INSIST(valrdataset == NULL &&
valsigrdataset == NULL);
valrdataset = rdataset;
valsigrdataset = sigrdataset;
} else {
/*
* This is one of (potentially)
* multiple answers to an ANY
* or SIG query. To keep things
* simple, we just start the
* validator right away rather
* than caching first and
* having to remember which
* rdatasets needed validation.
*/
result = valcreate(fctx, rmessage,
addrinfo, name,
rdataset->type,
rdataset,
sigrdataset,
valoptions, task);
}
} else if (CHAINING(rdataset)) {
if (rdataset->type == dns_rdatatype_cname) {
eresult = DNS_R_CNAME;
} else {
INSIST(rdataset->type ==
dns_rdatatype_dname);
eresult = DNS_R_DNAME;
}
}
} else if (!EXTERNAL(rdataset)) {
/*
* It's OK to cache this rdataset now.
*/
if (ANSWER(rdataset)) {
addedrdataset = ardataset;
} else if (ANSWERSIG(rdataset)) {
addedrdataset = asigrdataset;
} else {
addedrdataset = NULL;
}
if (CHAINING(rdataset)) {
if (rdataset->type == dns_rdatatype_cname) {
eresult = DNS_R_CNAME;
} else {
INSIST(rdataset->type ==
dns_rdatatype_dname);
eresult = DNS_R_DNAME;
}
}
if (rdataset->trust == dns_trust_glue &&
(rdataset->type == dns_rdatatype_ns ||
(rdataset->type == dns_rdatatype_rrsig &&
rdataset->covers == dns_rdatatype_ns)))
{
/*
* If the trust level is 'dns_trust_glue'
* then we are adding data from a referral
* we got while executing the search algorithm.
* New referral data always takes precedence
* over the existing cache contents.
*/
options = DNS_DBADD_FORCE;
} else if ((fctx->options & DNS_FETCHOPT_PREFETCH) != 0)
{
options = DNS_DBADD_PREFETCH;
} else {
options = 0;
}
if (ANSWER(rdataset) &&
rdataset->type != dns_rdatatype_rrsig)
{
isc_result_t tresult;
dns_name_t *noqname = NULL;
tresult = findnoqname(fctx, rmessage, name,
rdataset->type, &noqname);
if (tresult == ISC_R_SUCCESS &&
noqname != NULL)
{
(void) dns_rdataset_addnoqname(
rdataset, noqname);
}
}
/*
* Now we can add the rdataset.
*/
result = dns_db_addrdataset(fctx->cache,
node, NULL, now,
rdataset,
options,
addedrdataset);
if (result == DNS_R_UNCHANGED) {
if (ANSWER(rdataset) &&
ardataset != NULL &&
NEGATIVE(ardataset))
{
/*
* The answer in the cache is better
* than the answer we found, and is
* a negative cache entry, so we
* must set eresult appropriately.
*/
if (NXDOMAIN(ardataset)) {
eresult = DNS_R_NCACHENXDOMAIN;
} else {
eresult = DNS_R_NCACHENXRRSET;
}
}
result = ISC_R_SUCCESS;
} else if (result != ISC_R_SUCCESS) {
break;
}
}
}
if (valrdataset != NULL) {
dns_rdatatype_t vtype = fctx->type;
if (CHAINING(valrdataset)) {
if (valrdataset->type == dns_rdatatype_cname) {
vtype = dns_rdatatype_cname;
} else {
vtype = dns_rdatatype_dname;
}
}
result = valcreate(fctx, rmessage, addrinfo, name, vtype,
valrdataset, valsigrdataset, valoptions,
task);
}
if (result == ISC_R_SUCCESS && have_answer) {
FCTX_ATTR_SET(fctx, FCTX_ATTR_HAVEANSWER);
if (event != NULL) {
/*
* Negative results must be indicated in event->result.
*/
if (dns_rdataset_isassociated(event->rdataset) &&
NEGATIVE(event->rdataset))
{
INSIST(eresult == DNS_R_NCACHENXDOMAIN ||
eresult == DNS_R_NCACHENXRRSET);
}
event->result = eresult;
if (adbp != NULL && *adbp != NULL) {
if (anodep != NULL && *anodep != NULL) {
dns_db_detachnode(*adbp, anodep);
}
dns_db_detach(adbp);
}
dns_db_attach(fctx->cache, adbp);
dns_db_transfernode(fctx->cache, &node, anodep);
clone_results(fctx);
}
}
if (node != NULL) {
dns_db_detachnode(fctx->cache, &node);
}
return (result);
}
static inline isc_result_t
cache_message(fetchctx_t *fctx, dns_message_t *rmessage,
dns_adbaddrinfo_t *addrinfo, isc_stdtime_t now)
{
isc_result_t result;
dns_section_t section;
dns_name_t *name;
FCTXTRACE("cache_message");
FCTX_ATTR_CLR(fctx, FCTX_ATTR_WANTCACHE);
LOCK(&fctx->res->buckets[fctx->bucketnum].lock);
for (section = DNS_SECTION_ANSWER;
section <= DNS_SECTION_ADDITIONAL;
section++) {
result = dns_message_firstname(rmessage, section);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(rmessage, section,
&name);
if ((name->attributes & DNS_NAMEATTR_CACHE) != 0) {
result = cache_name(fctx, rmessage, name,
addrinfo, now);
if (result != ISC_R_SUCCESS)
break;
}
result = dns_message_nextname(rmessage, section);
}
if (result != ISC_R_NOMORE)
break;
}
if (result == ISC_R_NOMORE)
result = ISC_R_SUCCESS;
UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
return (result);
}
/*
* Do what dns_ncache_addoptout() does, and then compute an appropriate eresult.
*/
static isc_result_t
ncache_adderesult(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
dns_rdatatype_t covers, isc_stdtime_t now, dns_ttl_t maxttl,
bool optout, bool secure,
dns_rdataset_t *ardataset, isc_result_t *eresultp)
{
isc_result_t result;
dns_rdataset_t rdataset;
if (ardataset == NULL) {
dns_rdataset_init(&rdataset);
ardataset = &rdataset;
}
if (secure)
result = dns_ncache_addoptout(message, cache, node, covers,
now, maxttl, optout, ardataset);
else
result = dns_ncache_add(message, cache, node, covers, now,
maxttl, ardataset);
if (result == DNS_R_UNCHANGED || result == ISC_R_SUCCESS) {
/*
* If the cache now contains a negative entry and we
* care about whether it is DNS_R_NCACHENXDOMAIN or
* DNS_R_NCACHENXRRSET then extract it.
*/
if (NEGATIVE(ardataset)) {
/*
* The cache data is a negative cache entry.
*/
if (NXDOMAIN(ardataset))
*eresultp = DNS_R_NCACHENXDOMAIN;
else
*eresultp = DNS_R_NCACHENXRRSET;
} else {
/*
* Either we don't care about the nature of the
* cache rdataset (because no fetch is interested
* in the outcome), or the cache rdataset is not
* a negative cache entry. Whichever case it is,
* we can return success.
*
* XXXRTH There's a CNAME/DNAME problem here.
*/
*eresultp = ISC_R_SUCCESS;
}
result = ISC_R_SUCCESS;
}
if (ardataset == &rdataset && dns_rdataset_isassociated(ardataset))
dns_rdataset_disassociate(ardataset);
return (result);
}
static inline isc_result_t
ncache_message(fetchctx_t *fctx, dns_message_t *rmessage,
dns_adbaddrinfo_t *addrinfo, dns_rdatatype_t covers,
isc_stdtime_t now)
{
isc_result_t result, eresult;
dns_name_t *name;
dns_resolver_t *res;
dns_db_t **adbp;
dns_dbnode_t *node, **anodep;
dns_rdataset_t *ardataset;
bool need_validation, secure_domain;
dns_name_t *aname;
dns_fetchevent_t *event;
uint32_t ttl;
unsigned int valoptions = 0;
bool checknta = true;
FCTXTRACE("ncache_message");
FCTX_ATTR_CLR(fctx, FCTX_ATTR_WANTNCACHE);
res = fctx->res;
need_validation = false;
POST(need_validation);
secure_domain = false;
eresult = ISC_R_SUCCESS;
name = &fctx->name;
node = NULL;
/*
* XXXMPA remove when we follow cnames and adjust the setting
* of FCTX_ATTR_WANTNCACHE in noanswer_response().
*/
INSIST(rmessage->counts[DNS_SECTION_ANSWER] == 0);
/*
* Is DNSSEC validation required for this name?
*/
if (NONTA(fctx->options)) {
valoptions |= DNS_VALIDATOR_NONTA;
checknta = false;
}
if (fctx->res->view->enablevalidation) {
result = issecuredomain(res->view, name, fctx->type,
now, checknta, NULL, &secure_domain);
if (result != ISC_R_SUCCESS)
return (result);
if (!secure_domain && res->view->dlv != NULL) {
valoptions |= DNS_VALIDATOR_DLV;
secure_domain = true;
}
}
if ((fctx->options & DNS_FETCHOPT_NOCDFLAG) != 0)
valoptions |= DNS_VALIDATOR_NOCDFLAG;
if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0)
need_validation = false;
else
need_validation = secure_domain;
if (secure_domain) {
/*
* Mark all rdatasets as pending.
*/
dns_rdataset_t *trdataset;
dns_name_t *tname;
result = dns_message_firstname(rmessage,
DNS_SECTION_AUTHORITY);
while (result == ISC_R_SUCCESS) {
tname = NULL;
dns_message_currentname(rmessage,
DNS_SECTION_AUTHORITY,
&tname);
for (trdataset = ISC_LIST_HEAD(tname->list);
trdataset != NULL;
trdataset = ISC_LIST_NEXT(trdataset, link))
trdataset->trust = dns_trust_pending_answer;
result = dns_message_nextname(rmessage,
DNS_SECTION_AUTHORITY);
}
if (result != ISC_R_NOMORE)
return (result);
}
if (need_validation) {
/*
* Do negative response validation.
*/
result = valcreate(fctx, rmessage, addrinfo, name, fctx->type,
NULL, NULL, valoptions,
res->buckets[fctx->bucketnum].task);
/*
* If validation is necessary, return now. Otherwise continue
* to process the message, letting the validation complete
* in its own good time.
*/
return (result);
}
LOCK(&res->buckets[fctx->bucketnum].lock);
adbp = NULL;
aname = NULL;
anodep = NULL;
ardataset = NULL;
if (!HAVE_ANSWER(fctx)) {
event = ISC_LIST_HEAD(fctx->events);
if (event != NULL) {
adbp = &event->db;
aname = dns_fixedname_name(&event->foundname);
result = dns_name_copy(name, aname, NULL);
if (result != ISC_R_SUCCESS)
goto unlock;
anodep = &event->node;
ardataset = event->rdataset;
}
} else
event = NULL;
result = dns_db_findnode(fctx->cache, name, true, &node);
if (result != ISC_R_SUCCESS)
goto unlock;
/*
* If we are asking for a SOA record set the cache time
* to zero to facilitate locating the containing zone of
* a arbitrary zone.
*/
ttl = fctx->res->view->maxncachettl;
if (fctx->type == dns_rdatatype_soa &&
covers == dns_rdatatype_any &&
fctx->res->zero_no_soa_ttl)
ttl = 0;
result = ncache_adderesult(rmessage, fctx->cache, node,
covers, now, ttl, false,
false, ardataset, &eresult);
if (result != ISC_R_SUCCESS)
goto unlock;
if (!HAVE_ANSWER(fctx)) {
FCTX_ATTR_SET(fctx, FCTX_ATTR_HAVEANSWER);
if (event != NULL) {
event->result = eresult;
if (adbp != NULL && *adbp != NULL) {
if (anodep != NULL && *anodep != NULL)
dns_db_detachnode(*adbp, anodep);
dns_db_detach(adbp);
}
dns_db_attach(fctx->cache, adbp);
dns_db_transfernode(fctx->cache, &node, anodep);
clone_results(fctx);
}
}
unlock:
UNLOCK(&res->buckets[fctx->bucketnum].lock);
if (node != NULL)
dns_db_detachnode(fctx->cache, &node);
return (result);
}
static inline void
mark_related(dns_name_t *name, dns_rdataset_t *rdataset,
bool external, bool gluing)
{
name->attributes |= DNS_NAMEATTR_CACHE;
if (gluing) {
rdataset->trust = dns_trust_glue;
/*
* Glue with 0 TTL causes problems. We force the TTL to
* 1 second to prevent this.
*/
if (rdataset->ttl == 0)
rdataset->ttl = 1;
} else
rdataset->trust = dns_trust_additional;
/*
* Avoid infinite loops by only marking new rdatasets.
*/
if (!CACHE(rdataset)) {
name->attributes |= DNS_NAMEATTR_CHASE;
rdataset->attributes |= DNS_RDATASETATTR_CHASE;
}
rdataset->attributes |= DNS_RDATASETATTR_CACHE;
if (external)
rdataset->attributes |= DNS_RDATASETATTR_EXTERNAL;
}
static isc_result_t
check_section(void *arg, dns_name_t *addname, dns_rdatatype_t type,
dns_section_t section)
{
dns_chkarg_t *chkarg = arg;
fetchctx_t *fctx = chkarg->fctx;
dns_message_t *rmessage = chkarg->rmessage;
isc_result_t result;
dns_name_t *name = NULL;
dns_rdataset_t *rdataset = NULL;
bool external;
dns_rdatatype_t rtype;
bool gluing;
REQUIRE(VALID_FCTX(fctx));
#if CHECK_FOR_GLUE_IN_ANSWER
if (section == DNS_SECTION_ANSWER && type != dns_rdatatype_a)
return (ISC_R_SUCCESS);
#endif
gluing = (GLUING(fctx) ||
(fctx->type == dns_rdatatype_ns &&
dns_name_equal(&fctx->name, dns_rootname)));
result = dns_message_findname(rmessage, section, addname,
dns_rdatatype_any, 0, &name, NULL);
if (result == ISC_R_SUCCESS) {
external = !dns_name_issubdomain(name, &fctx->domain);
if (type == dns_rdatatype_a) {
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
if (rdataset->type == dns_rdatatype_rrsig)
rtype = rdataset->covers;
else
rtype = rdataset->type;
if (rtype == dns_rdatatype_a ||
rtype == dns_rdatatype_aaaa)
mark_related(name, rdataset, external,
gluing);
}
} else {
result = dns_message_findtype(name, type, 0,
&rdataset);
if (result == ISC_R_SUCCESS) {
mark_related(name, rdataset, external, gluing);
/*
* Do we have its SIG too?
*/
rdataset = NULL;
result = dns_message_findtype(name,
dns_rdatatype_rrsig,
type, &rdataset);
if (result == ISC_R_SUCCESS)
mark_related(name, rdataset, external,
gluing);
}
}
}
return (ISC_R_SUCCESS);
}
static isc_result_t
check_related(void *arg, dns_name_t *addname, dns_rdatatype_t type) {
return (check_section(arg, addname, type, DNS_SECTION_ADDITIONAL));
}
#ifndef CHECK_FOR_GLUE_IN_ANSWER
#define CHECK_FOR_GLUE_IN_ANSWER 0
#endif
#if CHECK_FOR_GLUE_IN_ANSWER
static isc_result_t
check_answer(void *arg, dns_name_t *addname, dns_rdatatype_t type) {
return (check_section(arg, addname, type, DNS_SECTION_ANSWER));
}
#endif
static void
chase_additional(fetchctx_t *fctx, dns_message_t *rmessage) {
bool rescan;
dns_section_t section = DNS_SECTION_ADDITIONAL;
isc_result_t result;
again:
rescan = false;
for (result = dns_message_firstname(rmessage, section);
result == ISC_R_SUCCESS;
result = dns_message_nextname(rmessage, section)) {
dns_name_t *name = NULL;
dns_rdataset_t *rdataset;
dns_message_currentname(rmessage, DNS_SECTION_ADDITIONAL,
&name);
if ((name->attributes & DNS_NAMEATTR_CHASE) == 0)
continue;
name->attributes &= ~DNS_NAMEATTR_CHASE;
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
if (CHASE(rdataset)) {
dns_chkarg_t chkarg;
chkarg.fctx = fctx;
chkarg.rmessage = rmessage;
rdataset->attributes &= ~DNS_RDATASETATTR_CHASE;
(void)dns_rdataset_additionaldata(rdataset,
check_related,
&chkarg);
rescan = true;
}
}
}
if (rescan)
goto again;
}
static bool
is_answeraddress_allowed(dns_view_t *view, dns_name_t *name,
dns_rdataset_t *rdataset)
{
isc_result_t result;
dns_rdata_t rdata = DNS_RDATA_INIT;
struct in_addr ina;
struct in6_addr in6a;
isc_netaddr_t netaddr;
char addrbuf[ISC_NETADDR_FORMATSIZE];
char namebuf[DNS_NAME_FORMATSIZE];
char classbuf[64];
char typebuf[64];
int match;
/* By default, we allow any addresses. */
if (view->denyansweracl == NULL)
return (true);
/*
* If the owner name matches one in the exclusion list, either exactly
* or partially, allow it.
*/
if (view->answeracl_exclude != NULL) {
dns_rbtnode_t *node = NULL;
result = dns_rbt_findnode(view->answeracl_exclude, name, NULL,
&node, NULL, 0, NULL, NULL);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
return (true);
}
/*
* Otherwise, search the filter list for a match for each address
* record. If a match is found, the address should be filtered,
* so should the entire answer.
*/
for (result = dns_rdataset_first(rdataset);
result == ISC_R_SUCCESS;
result = dns_rdataset_next(rdataset)) {
dns_rdata_reset(&rdata);
dns_rdataset_current(rdataset, &rdata);
if (rdataset->type == dns_rdatatype_a) {
INSIST(rdata.length == sizeof(ina.s_addr));
memmove(&ina.s_addr, rdata.data, sizeof(ina.s_addr));
isc_netaddr_fromin(&netaddr, &ina);
} else {
INSIST(rdata.length == sizeof(in6a.s6_addr));
memmove(in6a.s6_addr, rdata.data, sizeof(in6a.s6_addr));
isc_netaddr_fromin6(&netaddr, &in6a);
}
result = dns_acl_match(&netaddr, NULL, view->denyansweracl,
&view->aclenv, &match, NULL);
if (result == ISC_R_SUCCESS && match > 0) {
isc_netaddr_format(&netaddr, addrbuf, sizeof(addrbuf));
dns_name_format(name, namebuf, sizeof(namebuf));
dns_rdatatype_format(rdataset->type, typebuf,
sizeof(typebuf));
dns_rdataclass_format(rdataset->rdclass, classbuf,
sizeof(classbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
"answer address %s denied for %s/%s/%s",
addrbuf, namebuf, typebuf, classbuf);
return (false);
}
}
return (true);
}
static bool
is_answertarget_allowed(fetchctx_t *fctx, dns_name_t *qname, dns_name_t *rname,
dns_rdataset_t *rdataset, bool *chainingp)
{
isc_result_t result;
dns_rbtnode_t *node = NULL;
char qnamebuf[DNS_NAME_FORMATSIZE];
char tnamebuf[DNS_NAME_FORMATSIZE];
char classbuf[64];
char typebuf[64];
dns_name_t *tname = NULL;
dns_rdata_cname_t cname;
dns_rdata_dname_t dname;
dns_view_t *view = fctx->res->view;
dns_rdata_t rdata = DNS_RDATA_INIT;
unsigned int nlabels;
dns_fixedname_t fixed;
dns_name_t prefix;
int order;
REQUIRE(rdataset != NULL);
REQUIRE(rdataset->type == dns_rdatatype_cname ||
rdataset->type == dns_rdatatype_dname);
/*
* By default, we allow any target name.
* If newqname != NULL we also need to extract the newqname.
*/
if (chainingp == NULL && view->denyanswernames == NULL)
return (true);
result = dns_rdataset_first(rdataset);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
dns_rdataset_current(rdataset, &rdata);
switch (rdataset->type) {
case dns_rdatatype_cname:
result = dns_rdata_tostruct(&rdata, &cname, NULL);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
tname = &cname.cname;
break;
case dns_rdatatype_dname:
if (dns_name_fullcompare(qname, rname, &order, &nlabels) !=
dns_namereln_subdomain)
{
return (true);
}
result = dns_rdata_tostruct(&rdata, &dname, NULL);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
dns_name_init(&prefix, NULL);
tname = dns_fixedname_initname(&fixed);
nlabels = dns_name_countlabels(rname);
dns_name_split(qname, nlabels, &prefix, NULL);
result = dns_name_concatenate(&prefix, &dname.dname, tname,
NULL);
if (result == DNS_R_NAMETOOLONG) {
if (chainingp != NULL) {
*chainingp = true;
}
return (true);
}
RUNTIME_CHECK(result == ISC_R_SUCCESS);
break;
default:
INSIST(0);
ISC_UNREACHABLE();
}
if (chainingp != NULL)
*chainingp = true;
if (view->denyanswernames == NULL)
return (true);
/*
* If the owner name matches one in the exclusion list, either exactly
* or partially, allow it.
*/
if (view->answernames_exclude != NULL) {
result = dns_rbt_findnode(view->answernames_exclude, qname,
NULL, &node, NULL, 0, NULL, NULL);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
return (true);
}
/*
* If the target name is a subdomain of the search domain, allow it.
*
* Note that if BIND is configured as a forwarding DNS server, the
* search domain will always match the root domain ("."), so we
* must also check whether forwarding is enabled so that filters
* can be applied; see GL #1574.
*/
if ((fctx->fwdpolicy == dns_fwdpolicy_none) &&
dns_name_issubdomain(tname, &fctx->domain)) {
return (true);
}
/*
* Otherwise, apply filters.
*/
result = dns_rbt_findnode(view->denyanswernames, tname, NULL, &node,
NULL, 0, NULL, NULL);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
dns_name_format(qname, qnamebuf, sizeof(qnamebuf));
dns_name_format(tname, tnamebuf, sizeof(tnamebuf));
dns_rdatatype_format(rdataset->type, typebuf, sizeof(typebuf));
dns_rdataclass_format(view->rdclass, classbuf,
sizeof(classbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
"%s target %s denied for %s/%s",
typebuf, tnamebuf, qnamebuf, classbuf);
return (false);
}
return (true);
}
static void
trim_ns_ttl(fetchctx_t *fctx, dns_name_t *name, dns_rdataset_t *rdataset) {
char ns_namebuf[DNS_NAME_FORMATSIZE];
char namebuf[DNS_NAME_FORMATSIZE];
char tbuf[DNS_RDATATYPE_FORMATSIZE];
if (fctx->ns_ttl_ok && rdataset->ttl > fctx->ns_ttl) {
dns_name_format(name, ns_namebuf, sizeof(ns_namebuf));
dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
dns_rdatatype_format(fctx->type, tbuf, sizeof(tbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(10),
"fctx %p: trimming ttl of %s/NS for %s/%s: "
"%u -> %u", fctx, ns_namebuf, namebuf, tbuf,
rdataset->ttl, fctx->ns_ttl);
rdataset->ttl = fctx->ns_ttl;
}
}
/*
* Handle a no-answer response (NXDOMAIN, NXRRSET, or referral).
* If look_in_options has LOOK_FOR_NS_IN_ANSWER then we look in the answer
* section for the NS RRset if the query type is NS; if it has
* LOOK_FOR_GLUE_IN_ANSWER we look for glue incorrectly returned in the answer
* section for A and AAAA queries.
*/
#define LOOK_FOR_NS_IN_ANSWER 0x1
#define LOOK_FOR_GLUE_IN_ANSWER 0x2
static isc_result_t
noanswer_response(fetchctx_t *fctx, dns_message_t *message,
dns_name_t *oqname, unsigned int look_in_options)
{
isc_result_t result;
dns_name_t *name, *qname, *ns_name, *soa_name, *ds_name, *save_name;
dns_rdataset_t *rdataset, *ns_rdataset;
bool aa, negative_response;
dns_rdatatype_t type, save_type;
dns_section_t section;
FCTXTRACE("noanswer_response");
if ((look_in_options & LOOK_FOR_NS_IN_ANSWER) != 0) {
INSIST(fctx->type == dns_rdatatype_ns);
section = DNS_SECTION_ANSWER;
} else
section = DNS_SECTION_AUTHORITY;
/*
* Setup qname.
*/
if (oqname == NULL) {
/*
* We have a normal, non-chained negative response or
* referral.
*/
if ((message->flags & DNS_MESSAGEFLAG_AA) != 0)
aa = true;
else
aa = false;
qname = &fctx->name;
} else {
/*
* We're being invoked by answer_response() after it has
* followed a CNAME/DNAME chain.
*/
qname = oqname;
aa = false;
/*
* If the current qname is not a subdomain of the query
* domain, there's no point in looking at the authority
* section without doing DNSSEC validation.
*
* Until we do that validation, we'll just return success
* in this case.
*/
if (!dns_name_issubdomain(qname, &fctx->domain))
return (ISC_R_SUCCESS);
}
/*
* We have to figure out if this is a negative response, or a
* referral.
*/
/*
* Sometimes we can tell if its a negative response by looking at
* the message header.
*/
negative_response = false;
if (message->rcode == dns_rcode_nxdomain ||
(message->counts[DNS_SECTION_ANSWER] == 0 &&
message->counts[DNS_SECTION_AUTHORITY] == 0))
negative_response = true;
/*
* Process the authority section.
*/
ns_name = NULL;
ns_rdataset = NULL;
soa_name = NULL;
ds_name = NULL;
save_name = NULL;
save_type = dns_rdatatype_none;
result = dns_message_firstname(message, section);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, section, &name);
if (dns_name_issubdomain(name, &fctx->domain)) {
/*
* Look for NS/SOA RRsets first.
*/
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
type = rdataset->type;
if (type == dns_rdatatype_rrsig)
type = rdataset->covers;
if (((type == dns_rdatatype_ns ||
type == dns_rdatatype_soa) &&
!dns_name_issubdomain(qname, name))) {
char qbuf[DNS_NAME_FORMATSIZE];
char nbuf[DNS_NAME_FORMATSIZE];
char tbuf[DNS_RDATATYPE_FORMATSIZE];
dns_rdatatype_format(type, tbuf,
sizeof(tbuf));
dns_name_format(name, nbuf,
sizeof(nbuf));
dns_name_format(qname, qbuf,
sizeof(qbuf));
log_formerr(fctx,
"unrelated %s %s in "
"%s authority section",
tbuf, nbuf, qbuf);
goto nextname;
}
if (type == dns_rdatatype_ns) {
/*
* NS or RRSIG NS.
*
* Only one set of NS RRs is allowed.
*/
if (rdataset->type ==
dns_rdatatype_ns) {
if (ns_name != NULL &&
name != ns_name) {
log_formerr(fctx,
"multiple NS "
"RRsets in "
"authority "
"section");
return (DNS_R_FORMERR);
}
ns_name = name;
ns_rdataset = rdataset;
}
name->attributes |=
DNS_NAMEATTR_CACHE;
rdataset->attributes |=
DNS_RDATASETATTR_CACHE;
rdataset->trust = dns_trust_glue;
}
if (type == dns_rdatatype_soa) {
/*
* SOA, or RRSIG SOA.
*
* Only one SOA is allowed.
*/
if (rdataset->type ==
dns_rdatatype_soa) {
if (soa_name != NULL &&
name != soa_name) {
log_formerr(fctx,
"multiple SOA "
"RRs in "
"authority "
"section");
return (DNS_R_FORMERR);
}
soa_name = name;
}
name->attributes |=
DNS_NAMEATTR_NCACHE;
rdataset->attributes |=
DNS_RDATASETATTR_NCACHE;
if (aa)
rdataset->trust =
dns_trust_authauthority;
else if (ISFORWARDER(fctx->addrinfo))
rdataset->trust =
dns_trust_answer;
else
rdataset->trust =
dns_trust_additional;
}
}
}
nextname:
result = dns_message_nextname(message, section);
if (result == ISC_R_NOMORE)
break;
else if (result != ISC_R_SUCCESS)
return (result);
}
log_ns_ttl(fctx, "noanswer_response");
if (ns_rdataset != NULL && dns_name_equal(&fctx->domain, ns_name) &&
!dns_name_equal(ns_name, dns_rootname))
trim_ns_ttl(fctx, ns_name, ns_rdataset);
/*
* A negative response has a SOA record (Type 2)
* and a optional NS RRset (Type 1) or it has neither
* a SOA or a NS RRset (Type 3, handled above) or
* rcode is NXDOMAIN (handled above) in which case
* the NS RRset is allowed (Type 4).
*/
if (soa_name != NULL)
negative_response = true;
result = dns_message_firstname(message, section);
while (result == ISC_R_SUCCESS) {
name = NULL;
dns_message_currentname(message, section, &name);
if (dns_name_issubdomain(name, &fctx->domain)) {
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
type = rdataset->type;
if (type == dns_rdatatype_rrsig)
type = rdataset->covers;
if (type == dns_rdatatype_nsec ||
type == dns_rdatatype_nsec3) {
/*
* NSEC or RRSIG NSEC.
*/
if (negative_response) {
name->attributes |=
DNS_NAMEATTR_NCACHE;
rdataset->attributes |=
DNS_RDATASETATTR_NCACHE;
} else if (type == dns_rdatatype_nsec) {
name->attributes |=
DNS_NAMEATTR_CACHE;
rdataset->attributes |=
DNS_RDATASETATTR_CACHE;
}
if (aa)
rdataset->trust =
dns_trust_authauthority;
else if (ISFORWARDER(fctx->addrinfo))
rdataset->trust =
dns_trust_answer;
else
rdataset->trust =
dns_trust_additional;
/*
* No additional data needs to be
* marked.
*/
} else if (type == dns_rdatatype_ds) {
bool checknta = true;
bool secure_domain = false;
isc_stdtime_t now;
/*
* DS or SIG DS.
*
* These should only be here if
* this is a referral, and there
* should only be one DS RRset.
*/
if (ns_name == NULL) {
log_formerr(fctx,
"DS with no "
"referral");
return (DNS_R_FORMERR);
}
if (rdataset->type ==
dns_rdatatype_ds) {
if (ds_name != NULL &&
name != ds_name) {
log_formerr(fctx,
"DS doesn't "
"match "
"referral "
"(NS)");
return (DNS_R_FORMERR);
}
ds_name = name;
}
name->attributes |=
DNS_NAMEATTR_CACHE;
rdataset->attributes |=
DNS_RDATASETATTR_CACHE;
isc_stdtime_get(&now);
if (NONTA(fctx->options)) {
checknta = false;
}
result = issecuredomain(fctx->res->view,
name, type, now,
checknta, NULL,
&secure_domain);
if (result != ISC_R_SUCCESS) {
return (result);
}
if (secure_domain) {
rdataset->trust =
dns_trust_pending_answer;
} else if (aa) {
rdataset->trust =
dns_trust_authauthority;
} else if (ISFORWARDER(fctx->addrinfo))
{
rdataset->trust =
dns_trust_answer;
} else {
rdataset->trust =
dns_trust_additional;
}
}
}
} else {
save_name = name;
save_type = ISC_LIST_HEAD(name->list)->type;
}
result = dns_message_nextname(message, section);
if (result == ISC_R_NOMORE)
break;
else if (result != ISC_R_SUCCESS)
return (result);
}
/*
* Trigger lookups for DNS nameservers.
*/
if (negative_response && message->rcode == dns_rcode_noerror &&
fctx->type == dns_rdatatype_ds && soa_name != NULL &&
dns_name_equal(soa_name, qname) &&
!dns_name_equal(qname, dns_rootname))
return (DNS_R_CHASEDSSERVERS);
/*
* Did we find anything?
*/
if (!negative_response && ns_name == NULL) {
/*
* Nope.
*/
if (oqname != NULL) {
/*
* We've already got a partial CNAME/DNAME chain,
* and haven't found else anything useful here, but
* no error has occurred since we have an answer.
*/
return (ISC_R_SUCCESS);
} else {
/*
* The responder is insane.
*/
if (save_name == NULL) {
log_formerr(fctx, "invalid response");
return (DNS_R_FORMERR);
}
if (!dns_name_issubdomain(save_name, &fctx->domain)) {
char nbuf[DNS_NAME_FORMATSIZE];
char dbuf[DNS_NAME_FORMATSIZE];
char tbuf[DNS_RDATATYPE_FORMATSIZE];
dns_rdatatype_format(save_type, tbuf,
sizeof(tbuf));
dns_name_format(save_name, nbuf, sizeof(nbuf));
dns_name_format(&fctx->domain, dbuf,
sizeof(dbuf));
log_formerr(fctx, "Name %s (%s) not subdomain"
" of zone %s -- invalid response",
nbuf, tbuf, dbuf);
} else {
log_formerr(fctx, "invalid response");
}
return (DNS_R_FORMERR);
}
}
/*
* If we found both NS and SOA, they should be the same name.
*/
if (ns_name != NULL && soa_name != NULL && ns_name != soa_name) {
log_formerr(fctx, "NS/SOA mismatch");
return (DNS_R_FORMERR);
}
/*
* Do we have a referral? (We only want to follow a referral if
* we're not following a chain.)
*/
if (!negative_response && ns_name != NULL && oqname == NULL) {
dns_chkarg_t chkarg;
/*
* We already know ns_name is a subdomain of fctx->domain.
* If ns_name is equal to fctx->domain, we're not making
* progress. We return DNS_R_FORMERR so that we'll keep
* trying other servers.
*/
if (dns_name_equal(ns_name, &fctx->domain)) {
log_formerr(fctx, "non-improving referral");
return (DNS_R_FORMERR);
}
/*
* If the referral name is not a parent of the query
* name, consider the responder insane.
*/
if (! dns_name_issubdomain(&fctx->name, ns_name)) {
/* Logged twice */
log_formerr(fctx, "referral to non-parent");
FCTXTRACE("referral to non-parent");
return (DNS_R_FORMERR);
}
/*
* Mark any additional data related to this rdataset.
* It's important that we do this before we change the
* query domain.
*/
INSIST(ns_rdataset != NULL);
FCTX_ATTR_SET(fctx, FCTX_ATTR_GLUING);
chkarg.fctx = fctx;
chkarg.rmessage = message;
(void)dns_rdataset_additionaldata(ns_rdataset, check_related,
&chkarg);
#if CHECK_FOR_GLUE_IN_ANSWER
/*
* Look in the answer section for "glue" that is incorrectly
* returned as a answer. This is needed if the server also
* minimizes the response size by not adding records to the
* additional section that are in the answer section or if
* the record gets dropped due to message size constraints.
*/
if ((look_in_options & LOOK_FOR_GLUE_IN_ANSWER) != 0 &&
(fctx->type == dns_rdatatype_aaaa ||
fctx->type == dns_rdatatype_a)) {
dns_chkarg_t chkarg;
chkarg.fcx = fctx;
chkarg.rmessage = message;
(void)dns_rdataset_additionaldata(ns_rdataset,
check_answer, &chkarg);
}
#endif
FCTX_ATTR_CLR(fctx, FCTX_ATTR_GLUING);
/*
* NS rdatasets with 0 TTL cause problems.
* dns_view_findzonecut() will not find them when we
* try to follow the referral, and we'll SERVFAIL
* because the best nameservers are now above QDOMAIN.
* We force the TTL to 1 second to prevent this.
*/
if (ns_rdataset->ttl == 0)
ns_rdataset->ttl = 1;
/*
* Set the current query domain to the referral name.
*
* XXXRTH We should check if we're in forward-only mode, and
* if so we should bail out.
*/
INSIST(dns_name_countlabels(&fctx->domain) > 0);
fcount_decr(fctx);
dns_name_free(&fctx->domain, fctx->mctx);
if (dns_rdataset_isassociated(&fctx->nameservers))
dns_rdataset_disassociate(&fctx->nameservers);
dns_name_init(&fctx->domain, NULL);
result = dns_name_dup(ns_name, fctx->mctx, &fctx->domain);
if (result != ISC_R_SUCCESS)
return (result);
result = fcount_incr(fctx, true);
if (result != ISC_R_SUCCESS)
return (result);
FCTX_ATTR_SET(fctx, FCTX_ATTR_WANTCACHE);
fctx->ns_ttl_ok = false;
log_ns_ttl(fctx, "DELEGATION");
return (DNS_R_DELEGATION);
}
/*
* Since we're not doing a referral, we don't want to cache any
* NS RRs we may have found.
*/
if (ns_name != NULL)
ns_name->attributes &= ~DNS_NAMEATTR_CACHE;
if (negative_response && oqname == NULL)
FCTX_ATTR_SET(fctx, FCTX_ATTR_WANTNCACHE);
return (ISC_R_SUCCESS);
}
static bool
validinanswer(dns_rdataset_t *rdataset, fetchctx_t *fctx) {
if (rdataset->type == dns_rdatatype_nsec3) {
/*
* NSEC3 records are not allowed to
* appear in the answer section.
*/
log_formerr(fctx, "NSEC3 in answer");
return (false);
}
if (rdataset->type == dns_rdatatype_tkey) {
/*
* TKEY is not a valid record in a
* response to any query we can make.
*/
log_formerr(fctx, "TKEY in answer");
return (false);
}
if (rdataset->rdclass != fctx->res->rdclass) {
log_formerr(fctx, "Mismatched class in answer");
return (false);
}
return (true);
}
static isc_result_t
answer_response(fetchctx_t *fctx, dns_message_t *message) {
isc_result_t result;
dns_name_t *name = NULL, *qname = NULL, *ns_name = NULL;
dns_name_t *aname = NULL, *cname = NULL, *dname = NULL;
dns_rdataset_t *rdataset = NULL, *sigrdataset = NULL;
dns_rdataset_t *ardataset = NULL, *crdataset = NULL;
dns_rdataset_t *drdataset = NULL, *ns_rdataset = NULL;
bool done = false, aa;
unsigned int dname_labels, domain_labels;
bool chaining = false;
dns_rdatatype_t type;
dns_view_t *view = NULL;
dns_trust_t trust;
REQUIRE(VALID_FCTX(fctx));
FCTXTRACE("answer_response");
qname = &fctx->name;
view = fctx->res->view;
type = fctx->type;
/*
* There can be multiple RRSIG and SIG records at a name so
* we treat these types as a subset of ANY.
*/
if (type == dns_rdatatype_rrsig || type == dns_rdatatype_sig) {
type = dns_rdatatype_any;
}
/*
* Bigger than any valid DNAME label count.
*/
dname_labels = dns_name_countlabels(qname);
domain_labels = dns_name_countlabels(&fctx->domain);
/*
* Perform a single pass looking for the answer, cname or covering
* dname.
*/
for (result = dns_message_firstname(message, DNS_SECTION_ANSWER);
result == ISC_R_SUCCESS;
result = dns_message_nextname(message, DNS_SECTION_ANSWER))
{
int order;
unsigned int nlabels;
dns_namereln_t namereln;
name = NULL;
dns_message_currentname(message, DNS_SECTION_ANSWER, &name);
namereln = dns_name_fullcompare(qname, name, &order, &nlabels);
switch (namereln) {
case dns_namereln_equal:
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link))
{
if (rdataset->type == type ||
type == dns_rdatatype_any)
{
aname = name;
if (type != dns_rdatatype_any) {
ardataset = rdataset;
}
break;
}
if (rdataset->type == dns_rdatatype_cname) {
cname = name;
crdataset = rdataset;
break;
}
}
break;
case dns_namereln_subdomain:
/*
* In-scope DNAME records must have at least
* as many labels as the domain being queried.
* They also must be less that qname's labels
* and any previously found dname.
*/
if (nlabels >= dname_labels || nlabels < domain_labels)
{
continue;
}
/*
* We are looking for the shortest DNAME if there
* are multiple ones (which there shouldn't be).
*/
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link))
{
if (rdataset->type != dns_rdatatype_dname) {
continue;
}
dname = name;
drdataset = rdataset;
dname_labels = nlabels;
break;
}
break;
default:
break;
}
}
if (dname != NULL) {
aname = NULL;
ardataset = NULL;
cname = NULL;
crdataset = NULL;
} else if (aname != NULL) {
cname = NULL;
crdataset = NULL;
}
aa = (message->flags & DNS_MESSAGEFLAG_AA);
trust = aa ? dns_trust_authanswer : dns_trust_answer;
if (aname != NULL && type == dns_rdatatype_any) {
for (rdataset = ISC_LIST_HEAD(aname->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link))
{
dns_chkarg_t chkarg;
if (!validinanswer(rdataset, fctx)) {
return (DNS_R_FORMERR);
}
if ((fctx->type == dns_rdatatype_sig ||
fctx->type == dns_rdatatype_rrsig) &&
rdataset->type != fctx->type)
{
continue;
}
if ((rdataset->type == dns_rdatatype_a ||
rdataset->type == dns_rdatatype_aaaa) &&
!is_answeraddress_allowed(view, aname, rdataset))
{
return (DNS_R_SERVFAIL);
}
if ((rdataset->type == dns_rdatatype_cname ||
rdataset->type == dns_rdatatype_dname) &&
!is_answertarget_allowed(fctx, qname, aname,
rdataset, NULL))
{
return (DNS_R_SERVFAIL);
}
aname->attributes |= DNS_NAMEATTR_CACHE;
aname->attributes |= DNS_NAMEATTR_ANSWER;
rdataset->attributes |= DNS_RDATASETATTR_ANSWER;
rdataset->attributes |= DNS_RDATASETATTR_CACHE;
rdataset->trust = trust;
rdataset->attributes &= ~DNS_RDATASETATTR_CHASE;
chkarg.fctx = fctx;
chkarg.rmessage = message;
(void)dns_rdataset_additionaldata(rdataset,
check_related,
&chkarg);
}
} else if (aname != NULL) {
dns_chkarg_t chkarg;
if (!validinanswer(ardataset, fctx))
return (DNS_R_FORMERR);
if ((ardataset->type == dns_rdatatype_a ||
ardataset->type == dns_rdatatype_aaaa) &&
!is_answeraddress_allowed(view, aname, ardataset)) {
return (DNS_R_SERVFAIL);
}
if ((ardataset->type == dns_rdatatype_cname ||
ardataset->type == dns_rdatatype_dname) &&
type != ardataset->type &&
type != dns_rdatatype_any &&
!is_answertarget_allowed(fctx, qname, aname, ardataset,
NULL))
{
return (DNS_R_SERVFAIL);
}
aname->attributes |= DNS_NAMEATTR_CACHE;
aname->attributes |= DNS_NAMEATTR_ANSWER;
ardataset->attributes |= DNS_RDATASETATTR_ANSWER;
ardataset->attributes |= DNS_RDATASETATTR_CACHE;
ardataset->trust = trust;
chkarg.fctx = fctx;
chkarg.rmessage = message;
(void)dns_rdataset_additionaldata(ardataset, check_related,
&chkarg);
for (sigrdataset = ISC_LIST_HEAD(aname->list);
sigrdataset != NULL;
sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
if (!validinanswer(sigrdataset, fctx))
return (DNS_R_FORMERR);
if (sigrdataset->type != dns_rdatatype_rrsig ||
sigrdataset->covers != type)
continue;
sigrdataset->attributes |= DNS_RDATASETATTR_ANSWERSIG;
sigrdataset->attributes |= DNS_RDATASETATTR_CACHE;
sigrdataset->trust = trust;
break;
}
} else if (cname != NULL) {
if (!validinanswer(crdataset, fctx)) {
return (DNS_R_FORMERR);
}
if (type == dns_rdatatype_rrsig || type == dns_rdatatype_key ||
type == dns_rdatatype_nsec)
{
char buf[DNS_RDATATYPE_FORMATSIZE];
dns_rdatatype_format(type, buf, sizeof(buf));
log_formerr(fctx, "CNAME response for %s RR", buf);
return (DNS_R_FORMERR);
}
if (!is_answertarget_allowed(fctx, qname, cname, crdataset,
NULL))
{
return (DNS_R_SERVFAIL);
}
cname->attributes |= DNS_NAMEATTR_CACHE;
cname->attributes |= DNS_NAMEATTR_ANSWER;
cname->attributes |= DNS_NAMEATTR_CHAINING;
crdataset->attributes |= DNS_RDATASETATTR_ANSWER;
crdataset->attributes |= DNS_RDATASETATTR_CACHE;
crdataset->attributes |= DNS_RDATASETATTR_CHAINING;
crdataset->trust = trust;
for (sigrdataset = ISC_LIST_HEAD(cname->list);
sigrdataset != NULL;
sigrdataset = ISC_LIST_NEXT(sigrdataset, link))
{
if (!validinanswer(sigrdataset, fctx)) {
return (DNS_R_FORMERR);
}
if (sigrdataset->type != dns_rdatatype_rrsig ||
sigrdataset->covers != dns_rdatatype_cname)
{
continue;
}
sigrdataset->attributes |= DNS_RDATASETATTR_ANSWERSIG;
sigrdataset->attributes |= DNS_RDATASETATTR_CACHE;
sigrdataset->trust = trust;
break;
}
chaining = true;
} else if (dname != NULL) {
if (!validinanswer(drdataset, fctx)) {
return (DNS_R_FORMERR);
}
if (!is_answertarget_allowed(fctx, qname, dname, drdataset,
&chaining)) {
return (DNS_R_SERVFAIL);
}
dname->attributes |= DNS_NAMEATTR_CACHE;
dname->attributes |= DNS_NAMEATTR_ANSWER;
dname->attributes |= DNS_NAMEATTR_CHAINING;
drdataset->attributes |= DNS_RDATASETATTR_ANSWER;
drdataset->attributes |= DNS_RDATASETATTR_CACHE;
drdataset->attributes |= DNS_RDATASETATTR_CHAINING;
drdataset->trust = trust;
for (sigrdataset = ISC_LIST_HEAD(dname->list);
sigrdataset != NULL;
sigrdataset = ISC_LIST_NEXT(sigrdataset, link))
{
if (!validinanswer(sigrdataset, fctx)) {
return (DNS_R_FORMERR);
}
if (sigrdataset->type != dns_rdatatype_rrsig ||
sigrdataset->covers != dns_rdatatype_dname)
{
continue;
}
sigrdataset->attributes |= DNS_RDATASETATTR_ANSWERSIG;
sigrdataset->attributes |= DNS_RDATASETATTR_CACHE;
sigrdataset->trust = trust;
break;
}
} else {
log_formerr(fctx, "reply has no answer");
return (DNS_R_FORMERR);
}
/*
* This response is now potentially cacheable.
*/
FCTX_ATTR_SET(fctx, FCTX_ATTR_WANTCACHE);
/*
* Did chaining end before we got the final answer?
*/
if (chaining) {
return (ISC_R_SUCCESS);
}
/*
* We didn't end with an incomplete chain, so the rcode should be
* "no error".
*/
if (message->rcode != dns_rcode_noerror) {
log_formerr(fctx, "CNAME/DNAME chain complete, but RCODE "
"indicates error");
return (DNS_R_FORMERR);
}
/*
* Examine the authority section (if there is one).
*
* We expect there to be only one owner name for all the rdatasets
* in this section, and we expect that it is not external.
*/
result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
while (!done && result == ISC_R_SUCCESS) {
bool external;
name = NULL;
dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
external = !dns_name_issubdomain(name, &fctx->domain);
if (!external) {
/*
* We expect to find NS or SIG NS rdatasets, and
* nothing else.
*/
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
if (rdataset->type == dns_rdatatype_ns ||
(rdataset->type == dns_rdatatype_rrsig &&
rdataset->covers == dns_rdatatype_ns)) {
dns_chkarg_t chkarg;
name->attributes |=
DNS_NAMEATTR_CACHE;
rdataset->attributes |=
DNS_RDATASETATTR_CACHE;
if (aa && !chaining) {
rdataset->trust =
dns_trust_authauthority;
} else {
rdataset->trust =
dns_trust_additional;
}
if (rdataset->type == dns_rdatatype_ns)
{
ns_name = name;
ns_rdataset = rdataset;
}
/*
* Mark any additional data related
* to this rdataset.
*/
chkarg.fctx = fctx;
chkarg.rmessage = message;
(void)dns_rdataset_additionaldata(
rdataset,
check_related,
&chkarg);
done = true;
}
}
}
result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
}
if (result == ISC_R_NOMORE)
result = ISC_R_SUCCESS;
log_ns_ttl(fctx, "answer_response");
if (ns_rdataset != NULL && dns_name_equal(&fctx->domain, ns_name) &&
!dns_name_equal(ns_name, dns_rootname))
trim_ns_ttl(fctx, ns_name, ns_rdataset);
return (result);
}
static void
fctx_increference(fetchctx_t *fctx) {
REQUIRE(VALID_FCTX(fctx));
LOCK(&fctx->res->buckets[fctx->bucketnum].lock);
fctx->references++;
UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
}
static bool
fctx_decreference(fetchctx_t *fctx) {
bool bucket_empty = false;
REQUIRE(VALID_FCTX(fctx));
INSIST(fctx->references > 0);
fctx->references--;
if (fctx->references == 0) {
/*
* No one cares about the result of this fetch anymore.
*/
if (fctx->pending == 0 && fctx->nqueries == 0 &&
ISC_LIST_EMPTY(fctx->validators) && fctx->shuttingdown)
{
/*
* This fctx is already shutdown; we were just
* waiting for the last reference to go away.
*/
bucket_empty = fctx_unlink(fctx);
fctx_destroy(fctx);
} else {
/*
* Initiate shutdown.
*/
fctx_shutdown(fctx);
}
}
return (bucket_empty);
}
static void
resume_dslookup(isc_task_t *task, isc_event_t *event) {
dns_fetchevent_t *fevent;
dns_resolver_t *res;
fetchctx_t *fctx;
isc_result_t result;
bool bucket_empty;
bool locked = false;
unsigned int bucketnum;
dns_rdataset_t nameservers;
dns_fixedname_t fixed;
dns_name_t *domain;
REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
fevent = (dns_fetchevent_t *)event;
fctx = event->ev_arg;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
UNUSED(task);
FCTXTRACE("resume_dslookup");
if (fevent->node != NULL)
dns_db_detachnode(fevent->db, &fevent->node);
if (fevent->db != NULL)
dns_db_detach(&fevent->db);
dns_rdataset_init(&nameservers);
bucketnum = fctx->bucketnum;
/*
* Note: fevent->rdataset must be disassociated and
* isc_event_free(&event) be called before resuming
* processing of the 'fctx' to prevent use-after-free.
* 'fevent' is set to NULL so as to not have a dangling
* pointer.
*/
if (fevent->result == ISC_R_CANCELED) {
if (dns_rdataset_isassociated(fevent->rdataset)) {
dns_rdataset_disassociate(fevent->rdataset);
}
fevent = NULL;
isc_event_free(&event);
dns_resolver_destroyfetch(&fctx->nsfetch);
fctx_done(fctx, ISC_R_CANCELED, __LINE__);
} else if (fevent->result == ISC_R_SUCCESS) {
FCTXTRACE("resuming DS lookup");
dns_resolver_destroyfetch(&fctx->nsfetch);
if (dns_rdataset_isassociated(&fctx->nameservers)) {
dns_rdataset_disassociate(&fctx->nameservers);
}
dns_rdataset_clone(fevent->rdataset, &fctx->nameservers);
fctx->ns_ttl = fctx->nameservers.ttl;
fctx->ns_ttl_ok = true;
log_ns_ttl(fctx, "resume_dslookup");
if (dns_rdataset_isassociated(fevent->rdataset)) {
dns_rdataset_disassociate(fevent->rdataset);
}
fevent = NULL;
isc_event_free(&event);
fcount_decr(fctx);
dns_name_free(&fctx->domain, fctx->mctx);
dns_name_init(&fctx->domain, NULL);
result = dns_name_dup(&fctx->nsname, fctx->mctx, &fctx->domain);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
goto cleanup;
}
result = fcount_incr(fctx, true);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
goto cleanup;
}
/*
* Try again.
*/
fctx_try(fctx, true, false);
} else {
unsigned int n;
dns_rdataset_t *nsrdataset = NULL;
/*
* Retrieve state from fctx->nsfetch before we destroy it.
*/
dns_fixedname_init(&fixed);
domain = dns_fixedname_name(&fixed);
dns_name_copy(&fctx->nsfetch->private->domain, domain, NULL);
if (dns_name_equal(&fctx->nsname, domain)) {
if (dns_rdataset_isassociated(fevent->rdataset)) {
dns_rdataset_disassociate(fevent->rdataset);
}
fevent = NULL;
isc_event_free(&event);
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
dns_resolver_destroyfetch(&fctx->nsfetch);
goto cleanup;
}
if (dns_rdataset_isassociated(
&fctx->nsfetch->private->nameservers)) {
dns_rdataset_clone(
&fctx->nsfetch->private->nameservers,
&nameservers);
nsrdataset = &nameservers;
} else
domain = NULL;
dns_resolver_destroyfetch(&fctx->nsfetch);
n = dns_name_countlabels(&fctx->nsname);
dns_name_getlabelsequence(&fctx->nsname, 1, n - 1,
&fctx->nsname);
if (dns_rdataset_isassociated(fevent->rdataset))
dns_rdataset_disassociate(fevent->rdataset);
fevent = NULL;
isc_event_free(&event);
FCTXTRACE("continuing to look for parent's NS records");
result = dns_resolver_createfetch(fctx->res, &fctx->nsname,
dns_rdatatype_ns, domain,
nsrdataset, NULL,
fctx->options, task,
resume_dslookup, fctx,
&fctx->nsrrset, NULL,
&fctx->nsfetch);
/*
* fevent->rdataset (a.k.a. fctx->nsrrset) must not be
* accessed below this point to prevent races with
* another thread concurrently processing the fetch.
*/
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, result, __LINE__);
} else {
LOCK(&res->buckets[bucketnum].lock);
locked = true;
fctx->references++;
}
}
cleanup:
INSIST(event == NULL);
INSIST(fevent == NULL);
if (dns_rdataset_isassociated(&nameservers))
dns_rdataset_disassociate(&nameservers);
if (!locked)
LOCK(&res->buckets[bucketnum].lock);
bucket_empty = fctx_decreference(fctx);
UNLOCK(&res->buckets[bucketnum].lock);
if (bucket_empty)
empty_bucket(res);
}
static inline void
checknamessection(dns_message_t *message, dns_section_t section) {
isc_result_t result;
dns_name_t *name;
dns_rdata_t rdata = DNS_RDATA_INIT;
dns_rdataset_t *rdataset;
for (result = dns_message_firstname(message, section);
result == ISC_R_SUCCESS;
result = dns_message_nextname(message, section))
{
name = NULL;
dns_message_currentname(message, section, &name);
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link)) {
for (result = dns_rdataset_first(rdataset);
result == ISC_R_SUCCESS;
result = dns_rdataset_next(rdataset)) {
dns_rdataset_current(rdataset, &rdata);
if (!dns_rdata_checkowner(name, rdata.rdclass,
rdata.type,
false) ||
!dns_rdata_checknames(&rdata, name, NULL))
{
rdataset->attributes |=
DNS_RDATASETATTR_CHECKNAMES;
}
dns_rdata_reset(&rdata);
}
}
}
}
static void
checknames(dns_message_t *message) {
checknamessection(message, DNS_SECTION_ANSWER);
checknamessection(message, DNS_SECTION_AUTHORITY);
checknamessection(message, DNS_SECTION_ADDITIONAL);
}
/*
* Log server NSID at log level 'level'
*/
static void
log_nsid(isc_buffer_t *opt, size_t nsid_len, resquery_t *query,
int level, isc_mem_t *mctx)
{
static const char hex[17] = "0123456789abcdef";
char addrbuf[ISC_SOCKADDR_FORMATSIZE];
uint16_t buflen, i;
unsigned char *p, *nsid;
unsigned char *buf = NULL, *pbuf = NULL;
/* Allocate buffer for storing hex version of the NSID */
buflen = (uint16_t)nsid_len * 2 + 1;
buf = isc_mem_get(mctx, buflen);
if (buf == NULL)
goto cleanup;
pbuf = isc_mem_get(mctx, nsid_len + 1);
if (pbuf == NULL)
goto cleanup;
/* Convert to hex */
p = buf;
nsid = isc_buffer_current(opt);
for (i = 0; i < nsid_len; i++) {
*p++ = hex[(nsid[i] >> 4) & 0xf];
*p++ = hex[nsid[i] & 0xf];
}
*p = '\0';
/* Make printable version */
p = pbuf;
for (i = 0; i < nsid_len; i++) {
if (isprint(nsid[i]))
*p++ = nsid[i];
else
*p++ = '.';
}
*p = '\0';
isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf,
sizeof(addrbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, level,
"received NSID %s (\"%s\") from %s", buf, pbuf, addrbuf);
cleanup:
if (pbuf != NULL)
isc_mem_put(mctx, pbuf, nsid_len + 1);
if (buf != NULL)
isc_mem_put(mctx, buf, buflen);
}
static bool
iscname(fetchctx_t *fctx, dns_message_t *rmessage) {
isc_result_t result;
result = dns_message_findname(rmessage, DNS_SECTION_ANSWER,
&fctx->name, dns_rdatatype_cname, 0,
NULL, NULL);
return (result == ISC_R_SUCCESS ? true : false);
}
static bool
betterreferral(fetchctx_t *fctx, dns_message_t *message) {
isc_result_t result;
dns_name_t *name;
dns_rdataset_t *rdataset;
for (result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
result == ISC_R_SUCCESS;
result = dns_message_nextname(message, DNS_SECTION_AUTHORITY)) {
name = NULL;
dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
if (!isstrictsubdomain(name, &fctx->domain))
continue;
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
rdataset = ISC_LIST_NEXT(rdataset, link))
if (rdataset->type == dns_rdatatype_ns)
return (true);
}
return (false);
}
static void
process_opt(resquery_t *query, dns_rdataset_t *opt) {
dns_rdata_t rdata;
isc_buffer_t optbuf;
isc_result_t result;
uint16_t optcode;
uint16_t optlen;
unsigned char *optvalue;
dns_adbaddrinfo_t *addrinfo;
unsigned char cookie[CLIENT_COOKIE_SIZE];
bool seen_cookie = false;
bool seen_nsid = false;
result = dns_rdataset_first(opt);
if (result == ISC_R_SUCCESS) {
dns_rdata_init(&rdata);
dns_rdataset_current(opt, &rdata);
isc_buffer_init(&optbuf, rdata.data, rdata.length);
isc_buffer_add(&optbuf, rdata.length);
while (isc_buffer_remaininglength(&optbuf) >= 4) {
optcode = isc_buffer_getuint16(&optbuf);
optlen = isc_buffer_getuint16(&optbuf);
INSIST(optlen <= isc_buffer_remaininglength(&optbuf));
switch (optcode) {
case DNS_OPT_NSID:
if (!seen_nsid &&
query->options & DNS_FETCHOPT_WANTNSID)
log_nsid(&optbuf, optlen, query,
ISC_LOG_DEBUG(3),
query->fctx->res->mctx);
isc_buffer_forward(&optbuf, optlen);
seen_nsid = true;
break;
case DNS_OPT_COOKIE:
/*
* Only process the first cookie option.
*/
if (seen_cookie) {
isc_buffer_forward(&optbuf, optlen);
break;
}
optvalue = isc_buffer_current(&optbuf);
compute_cc(query, cookie, sizeof(cookie));
INSIST(query->rmessage->cc_bad == 0 &&
query->rmessage->cc_ok == 0);
if (optlen >= CLIENT_COOKIE_SIZE &&
memcmp(cookie, optvalue,
CLIENT_COOKIE_SIZE) == 0)
{
query->rmessage->cc_ok = 1;
inc_stats(query->fctx->res,
dns_resstatscounter_cookieok);
addrinfo = query->addrinfo;
dns_adb_setcookie(query->fctx->adb,
addrinfo, optvalue,
optlen);
} else
query->rmessage->cc_bad = 1;
isc_buffer_forward(&optbuf, optlen);
inc_stats(query->fctx->res,
dns_resstatscounter_cookiein);
seen_cookie = true;
break;
default:
isc_buffer_forward(&optbuf, optlen);
break;
}
}
INSIST(isc_buffer_remaininglength(&optbuf) == 0U);
}
}
static void
resquery_response(isc_task_t *task, isc_event_t *event) {
isc_result_t result = ISC_R_SUCCESS;
resquery_t *query = event->ev_arg;
dns_dispatchevent_t *devent = (dns_dispatchevent_t *)event;
bool keep_trying, get_nameservers, resend, nextitem;
bool truncated;
dns_message_t *rmessage = NULL;
dns_rdataset_t *opt;
fetchctx_t *fctx;
dns_name_t *fname;
dns_fixedname_t foundname;
isc_stdtime_t now;
isc_time_t tnow, *finish;
dns_adbaddrinfo_t *addrinfo;
unsigned int options;
unsigned int findoptions;
isc_result_t broken_server;
badnstype_t broken_type = badns_response;
bool no_response;
unsigned int bucketnum;
dns_resolver_t *res;
bool bucket_empty;
#ifdef HAVE_DNSTAP
isc_socket_t *sock = NULL;
isc_sockaddr_t localaddr, *la = NULL;
unsigned char zone[DNS_NAME_MAXWIRE];
dns_dtmsgtype_t dtmsgtype;
dns_compress_t cctx;
isc_region_t zr;
isc_buffer_t zb;
#endif /* HAVE_DNSTAP */
REQUIRE(VALID_QUERY(query));
fctx = query->fctx;
options = query->options;
REQUIRE(VALID_FCTX(fctx));
REQUIRE(event->ev_type == DNS_EVENT_DISPATCH);
dns_message_attach(query->rmessage, &rmessage);
QTRACE("response");
res = fctx->res;
if (isc_sockaddr_pf(&query->addrinfo->sockaddr) == PF_INET)
inc_stats(res, dns_resstatscounter_responsev4);
else
inc_stats(res, dns_resstatscounter_responsev6);
(void)isc_timer_touch(fctx->timer);
keep_trying = false;
broken_server = ISC_R_SUCCESS;
get_nameservers = false;
resend = false;
nextitem = false;
truncated = false;
finish = NULL;
no_response = false;
if (res->exiting) {
result = ISC_R_SHUTTINGDOWN;
FCTXTRACE("resolver shutting down");
goto done;
}
fctx->timeouts = 0;
fctx->timeout = false;
fctx->addrinfo = query->addrinfo;
/*
* XXXRTH We should really get the current time just once. We
* need a routine to convert from an isc_time_t to an
* isc_stdtime_t.
*/
TIME_NOW(&tnow);
finish = &tnow;
isc_stdtime_get(&now);
/*
* Did the dispatcher have a problem?
*/
if (devent->result != ISC_R_SUCCESS) {
if (devent->result == ISC_R_EOF &&
(query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
/*
* The problem might be that they
* don't understand EDNS0. Turn it
* off and try again.
*/
options |= DNS_FETCHOPT_NOEDNS0;
resend = true;
add_bad_edns(fctx, &query->addrinfo->sockaddr);
} else {
/*
* There's no hope for this query.
*/
keep_trying = true;
/*
* If this is a network error on an exclusive query
* socket, mark the server as bad so that we won't try
* it for this fetch again. Also adjust finish and
* no_response so that we penalize this address in SRTT
* adjustment later.
*/
if (query->exclusivesocket &&
(devent->result == ISC_R_HOSTUNREACH ||
devent->result == ISC_R_NETUNREACH ||
devent->result == ISC_R_CONNREFUSED ||
devent->result == ISC_R_CANCELED)) {
broken_server = devent->result;
broken_type = badns_unreachable;
finish = NULL;
no_response = true;
}
}
FCTXTRACE3("dispatcher failure", devent->result);
goto done;
}
if (query->tsig != NULL) {
result = dns_message_setquerytsig(rmessage, query->tsig);
if (result != ISC_R_SUCCESS) {
FCTXTRACE3("unable to set query tsig", result);
goto done;
}
}
if (query->tsigkey) {
result = dns_message_settsigkey(rmessage, query->tsigkey);
if (result != ISC_R_SUCCESS) {
FCTXTRACE3("unable to set tsig key", result);
goto done;
}
}
dns_message_setclass(rmessage, res->rdclass);
if ((options & DNS_FETCHOPT_TCP) == 0) {
if ((options & DNS_FETCHOPT_NOEDNS0) == 0)
dns_adb_setudpsize(fctx->adb, query->addrinfo,
isc_buffer_usedlength(&devent->buffer));
else
dns_adb_plainresponse(fctx->adb, query->addrinfo);
}
result = dns_message_parse(rmessage, &devent->buffer, 0);
if (result != ISC_R_SUCCESS) {
FCTXTRACE3("message failed to parse", result);
switch (result) {
case ISC_R_UNEXPECTEDEND:
if (!rmessage->question_ok ||
(rmessage->flags & DNS_MESSAGEFLAG_TC) == 0 ||
(options & DNS_FETCHOPT_TCP) != 0) {
/*
* Either the rmessage ended prematurely,
* and/or wasn't marked as being truncated,
* and/or this is a response to a query we
* sent over TCP. In all of these cases,
* something is wrong with the remote
* server and we don't want to retry using
* TCP.
*/
if ((query->options & DNS_FETCHOPT_NOEDNS0)
== 0) {
/*
* The problem might be that they
* don't understand EDNS0. Turn it
* off and try again.
*/
options |= DNS_FETCHOPT_NOEDNS0;
resend = true;
add_bad_edns(fctx,
&query->addrinfo->sockaddr);
inc_stats(res,
dns_resstatscounter_edns0fail);
} else {
broken_server = result;
keep_trying = true;
}
goto done;
}
/*
* We defer retrying via TCP for a bit so we can
* check out this rmessage further.
*/
truncated = true;
break;
case DNS_R_FORMERR:
if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
/*
* The problem might be that they
* don't understand EDNS0. Turn it
* off and try again.
*/
options |= DNS_FETCHOPT_NOEDNS0;
resend = true;
add_bad_edns(fctx, &query->addrinfo->sockaddr);
inc_stats(res, dns_resstatscounter_edns0fail);
} else {
broken_server = DNS_R_UNEXPECTEDRCODE;
keep_trying = true;
}
goto done;
default:
/*
* Something bad has happened.
*/
goto done;
}
}
/*
* Log the incoming packet.
*/
dns_message_logfmtpacket2(rmessage, "received packet from",
&query->addrinfo->sockaddr,
DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_PACKETS,
&dns_master_style_comment,
ISC_LOG_DEBUG(10), res->mctx);
#ifdef HAVE_DNSTAP
/*
* Log the response via dnstap.
*/
memset(&zr, 0, sizeof(zr));
result = dns_compress_init(&cctx, -1, res->mctx);
if (result == ISC_R_SUCCESS) {
isc_buffer_init(&zb, zone, sizeof(zone));
dns_compress_setmethods(&cctx, DNS_COMPRESS_NONE);
result = dns_name_towire(&fctx->domain, &cctx, &zb);
if (result == ISC_R_SUCCESS)
isc_buffer_usedregion(&zb, &zr);
dns_compress_invalidate(&cctx);
}
if ((fctx->qmessage->flags & DNS_MESSAGEFLAG_RD) != 0) {
dtmsgtype = DNS_DTTYPE_FR;
} else {
dtmsgtype = DNS_DTTYPE_RR;
}
if (query->exclusivesocket) {
sock = dns_dispatch_getentrysocket(query->dispentry);
} else {
sock = dns_dispatch_getsocket(query->dispatch);
}
if (sock != NULL) {
result = isc_socket_getsockname(sock, &localaddr);
if (result == ISC_R_SUCCESS) {
la = &localaddr;
}
}
dns_dt_send(res->view, dtmsgtype, la, &query->addrinfo->sockaddr,
(query->options & DNS_FETCHOPT_TCP),
&zr, &query->start, NULL, &devent->buffer);
#endif /* HAVE_DNSTAP */
if (rmessage->rdclass != res->rdclass) {
resend = true;
FCTXTRACE("bad class");
goto done;
}
/*
* Process receive opt record.
*/
opt = dns_message_getopt(rmessage);
if (opt != NULL)
process_opt(query, opt);
if (rmessage->cc_bad && (options & DNS_FETCHOPT_TCP) == 0) {
/*
* If the COOKIE is bad, assume it is an attack and
* keep listening for a good answer.
*/
nextitem = true;
if (isc_log_wouldlog(dns_lctx, ISC_LOG_INFO)) {
char addrbuf[ISC_SOCKADDR_FORMATSIZE];
isc_sockaddr_format(&query->addrinfo->sockaddr,
addrbuf, sizeof(addrbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"bad cookie from %s", addrbuf);
}
goto done;
}
/*
* Is the question the same as the one we asked?
* NOERROR/NXDOMAIN/YXDOMAIN/REFUSED/SERVFAIL/BADCOOKIE must have
* the same question.
* FORMERR/NOTIMP if they have a question section then it must match.
*/
switch (rmessage->rcode) {
case dns_rcode_notimp:
case dns_rcode_formerr:
if (rmessage->counts[DNS_SECTION_QUESTION] == 0)
break;
/* FALLTHROUGH */
case dns_rcode_nxrrset: /* Not expected. */
case dns_rcode_badcookie:
case dns_rcode_noerror:
case dns_rcode_nxdomain:
case dns_rcode_yxdomain:
case dns_rcode_refused:
case dns_rcode_servfail:
default:
result = same_question(fctx, rmessage);
if (result != ISC_R_SUCCESS) {
FCTXTRACE3("response did not match question", result);
nextitem = true;
goto done;
}
break;
}
/*
* If the rmessage is signed, check the signature. If not, this
* returns success anyway.
*/
result = dns_message_checksig(rmessage, res->view);
if (result != ISC_R_SUCCESS) {
FCTXTRACE3("signature check failed", result);
if (result == DNS_R_UNEXPECTEDTSIG ||
result == DNS_R_EXPECTEDTSIG) {
nextitem = true;
}
goto done;
}
/*
* The dispatcher should ensure we only get responses with QR set.
*/
INSIST((rmessage->flags & DNS_MESSAGEFLAG_QR) != 0);
/*
* INSIST() that the rmessage comes from the place we sent it to,
* since the dispatch code should ensure this.
*
* INSIST() that the rmessage id is correct (this should also be
* ensured by the dispatch code).
*/
/*
* If we have had a server cookie and don't get one retry over TCP.
* This may be a misconfigured anycast server or an attempt to send
* a spoofed response. Skip if we have a valid tsig.
*/
if (dns_message_gettsig(rmessage, NULL) == NULL &&
!rmessage->cc_ok && !rmessage->cc_bad &&
(options & DNS_FETCHOPT_TCP) == 0)
{
unsigned char cookie[COOKIE_BUFFER_SIZE];
if (dns_adb_getcookie(fctx->adb, query->addrinfo, cookie,
sizeof(cookie)) > CLIENT_COOKIE_SIZE)
{
if (isc_log_wouldlog(dns_lctx, ISC_LOG_INFO)) {
char addrbuf[ISC_SOCKADDR_FORMATSIZE];
isc_sockaddr_format(&query->addrinfo->sockaddr,
addrbuf, sizeof(addrbuf));
isc_log_write(
dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"missing expected cookie from %s",
addrbuf);
}
options |= DNS_FETCHOPT_TCP;
resend = true;
goto done;
}
/*
* XXXMPA When support for DNS COOKIE becomes ubiquitous, fall
* back to TCP for all non-COOKIE responses.
*/
}
/*
* We have an affirmative response to the query and we have
* previously got a response from this server which indicated
* EDNS may not be supported so we can now cache the lack of
* EDNS support.
*/
if (opt == NULL && !EDNSOK(query->addrinfo) &&
(rmessage->rcode == dns_rcode_noerror ||
rmessage->rcode == dns_rcode_nxdomain ||
rmessage->rcode == dns_rcode_refused ||
rmessage->rcode == dns_rcode_yxdomain) &&
bad_edns(fctx, &query->addrinfo->sockaddr)) {
dns_message_logpacket2(rmessage,
"received packet (bad edns) from",
&query->addrinfo->sockaddr,
DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER,
ISC_LOG_DEBUG(3),
res->mctx);
dns_adb_changeflags(fctx->adb, query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
} else if (opt == NULL && (rmessage->flags & DNS_MESSAGEFLAG_TC) == 0 &&
!EDNSOK(query->addrinfo) &&
(rmessage->rcode == dns_rcode_noerror ||
rmessage->rcode == dns_rcode_nxdomain) &&
(query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
/*
* We didn't get a OPT record in response to a EDNS query.
*
* Old versions of named incorrectly drop the OPT record
* when there is a signed, truncated response so we check
* that TC is not set.
*
* Record that the server is not talking EDNS. While this
* should be safe to do for any rcode we limit it to NOERROR
* and NXDOMAIN.
*/
dns_message_logpacket2(rmessage, "received packet (no opt) from",
&query->addrinfo->sockaddr,
DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER,
ISC_LOG_DEBUG(3), res->mctx);
dns_adb_changeflags(fctx->adb, query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
}
/*
* If we get a non error EDNS response record the fact so we
* won't fallback to plain DNS in the future for this server.
*/
if (opt != NULL && !EDNSOK(query->addrinfo) &&
(query->options & DNS_FETCHOPT_NOEDNS0) == 0 &&
(rmessage->rcode == dns_rcode_noerror ||
rmessage->rcode == dns_rcode_nxdomain ||
rmessage->rcode == dns_rcode_refused ||
rmessage->rcode == dns_rcode_yxdomain)) {
dns_adb_changeflags(fctx->adb, query->addrinfo,
FCTX_ADDRINFO_EDNSOK,
FCTX_ADDRINFO_EDNSOK);
}
/*
* Deal with truncated responses by retrying using TCP.
*/
if ((rmessage->flags & DNS_MESSAGEFLAG_TC) != 0)
truncated = true;
if (truncated) {
inc_stats(res, dns_resstatscounter_truncated);
if ((options & DNS_FETCHOPT_TCP) != 0) {
broken_server = DNS_R_TRUNCATEDTCP;
keep_trying = true;
} else {
options |= DNS_FETCHOPT_TCP;
resend = true;
}
FCTXTRACE3("message truncated", result);
goto done;
}
/*
* Is it a query response?
*/
if (rmessage->opcode != dns_opcode_query) {
/* XXXRTH Log */
broken_server = DNS_R_UNEXPECTEDOPCODE;
keep_trying = true;
FCTXTRACE("invalid rmessage opcode");
goto done;
}
/*
* Update statistics about erroneous responses.
*/
if (rmessage->rcode != dns_rcode_noerror) {
switch (rmessage->rcode) {
case dns_rcode_nxdomain:
inc_stats(res, dns_resstatscounter_nxdomain);
break;
case dns_rcode_servfail:
inc_stats(res, dns_resstatscounter_servfail);
break;
case dns_rcode_formerr:
inc_stats(res, dns_resstatscounter_formerr);
break;
case dns_rcode_refused:
inc_stats(res, dns_resstatscounter_refused);
break;
case dns_rcode_badvers:
inc_stats(res, dns_resstatscounter_badvers);
break;
case dns_rcode_badcookie:
inc_stats(res, dns_resstatscounter_badcookie);
break;
default:
inc_stats(res, dns_resstatscounter_othererror);
break;
}
}
/*
* Is the remote server broken, or does it dislike us?
*/
if (rmessage->rcode != dns_rcode_noerror &&
rmessage->rcode != dns_rcode_yxdomain &&
rmessage->rcode != dns_rcode_nxdomain) {
isc_buffer_t b;
char code[64];
unsigned char cookie[COOKIE_BUFFER_SIZE];
/*
* Some servers do not ignore unknown EDNS options.
*/
if (!NOCOOKIE(query->addrinfo) &&
(rmessage->rcode == dns_rcode_formerr ||
rmessage->rcode == dns_rcode_notimp ||
rmessage->rcode == dns_rcode_refused) &&
dns_adb_getcookie(fctx->adb, query->addrinfo,
cookie, sizeof(cookie)) == 0U) {
dns_adb_changeflags(fctx->adb, query->addrinfo,
FCTX_ADDRINFO_NOCOOKIE,
FCTX_ADDRINFO_NOCOOKIE);
resend = true;
} else if ((rmessage->rcode == dns_rcode_formerr ||
rmessage->rcode == dns_rcode_notimp ||
(rmessage->rcode == dns_rcode_servfail &&
dns_message_getopt(rmessage) == NULL)) &&
(query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
/*
* It's very likely they don't like EDNS0.
* If the response code is SERVFAIL, also check if the
* response contains an OPT RR and don't cache the
* failure since it can be returned for various other
* reasons.
*
* XXXRTH We should check if the question
* we're asking requires EDNS0, and
* if so, we should bail out.
*/
options |= DNS_FETCHOPT_NOEDNS0;
resend = true;
/*
* Remember that they may not like EDNS0.
*/
add_bad_edns(fctx, &query->addrinfo->sockaddr);
inc_stats(res, dns_resstatscounter_edns0fail);
} else if (rmessage->rcode == dns_rcode_formerr) {
if (ISFORWARDER(query->addrinfo)) {
/*
* This forwarder doesn't understand us,
* but other forwarders might. Keep trying.
*/
broken_server = DNS_R_REMOTEFORMERR;
keep_trying = true;
} else {
/*
* The server doesn't understand us. Since
* all servers for a zone need similar
* capabilities, we assume that we will get
* FORMERR from all servers, and thus we
* cannot make any more progress with this
* fetch.
*/
log_formerr(fctx, "server sent FORMERR");
result = DNS_R_FORMERR;
}
} else if (rmessage->rcode == dns_rcode_badvers) {
unsigned int version;
bool setnocookie = false;
#if DNS_EDNS_VERSION > 0
unsigned int flags, mask;
#endif
/*
* Some servers return BADVERS to unknown
* EDNS options. This cannot be long term
* strategy. Do not disable COOKIE if we have
* already have received a COOKIE from this
* server.
*/
if (dns_adb_getcookie(fctx->adb, query->addrinfo,
cookie, sizeof(cookie)) == 0U) {
if (!NOCOOKIE(query->addrinfo))
setnocookie = true;
dns_adb_changeflags(fctx->adb, query->addrinfo,
FCTX_ADDRINFO_NOCOOKIE,
FCTX_ADDRINFO_NOCOOKIE);
}
INSIST(opt != NULL);
version = (opt->ttl >> 16) & 0xff;
#if DNS_EDNS_VERSION > 0
flags = (version << DNS_FETCHOPT_EDNSVERSIONSHIFT) |
DNS_FETCHOPT_EDNSVERSIONSET;
mask = DNS_FETCHOPT_EDNSVERSIONMASK |
DNS_FETCHOPT_EDNSVERSIONSET;
#endif
/*
* Record that we got a good EDNS response.
*/
if (query->ednsversion > (int)version &&
!EDNSOK(query->addrinfo)) {
dns_adb_changeflags(fctx->adb, query->addrinfo,
FCTX_ADDRINFO_EDNSOK,
FCTX_ADDRINFO_EDNSOK);
}
/*
* RFC 2671 was not clear that unknown options should
* be ignored. RFC 6891 is clear that that they
* should be ignored. If we are supporting the
* experimental EDNS > 0 then perform strict
* version checking of badvers responses. We won't
* be sending COOKIE etc. in that case.
*/
#if DNS_EDNS_VERSION > 0
if ((int)version < query->ednsversion) {
dns_adb_changeflags(fctx->adb, query->addrinfo,
flags, mask);
resend = true;
} else {
broken_server = DNS_R_BADVERS;
keep_trying = true;
}
#else
if (version == 0U && setnocookie) {
resend = true;
} else {
broken_server = DNS_R_BADVERS;
keep_trying = true;
}
#endif
} else if (rmessage->rcode == dns_rcode_badcookie &&
rmessage->cc_ok) {
/*
* We have recorded the new cookie.
*/
if (BADCOOKIE(query->addrinfo))
query->options |= DNS_FETCHOPT_TCP;
query->addrinfo->flags |= FCTX_ADDRINFO_BADCOOKIE;
resend = true;
} else {
/*
* XXXRTH log.
*/
broken_server = DNS_R_UNEXPECTEDRCODE;
INSIST(broken_server != ISC_R_SUCCESS);
keep_trying = true;
}
isc_buffer_init(&b, code, sizeof(code) - 1);
dns_rcode_totext(rmessage->rcode, &b);
code[isc_buffer_usedlength(&b)] = '\0';
FCTXTRACE2("remote server broken: returned ", code);
goto done;
}
/*
* Is the server lame?
*/
if (res->lame_ttl != 0 && !ISFORWARDER(query->addrinfo) &&
is_lame(fctx, rmessage)) {
inc_stats(res, dns_resstatscounter_lame);
log_lame(fctx, query->addrinfo);
result = dns_adb_marklame(fctx->adb, query->addrinfo,
&fctx->name, fctx->type,
now + res->lame_ttl);
if (result != ISC_R_SUCCESS)
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_ERROR,
"could not mark server as lame: %s",
isc_result_totext(result));
broken_server = DNS_R_LAME;
keep_trying = true;
FCTXTRACE("lame server");
goto done;
}
/*
* Enforce delegations only zones like NET and COM.
*/
if (!ISFORWARDER(query->addrinfo) &&
dns_view_isdelegationonly(res->view, &fctx->domain) &&
!dns_name_equal(&fctx->domain, &fctx->name) &&
fix_mustbedelegationornxdomain(rmessage, fctx)) {
char namebuf[DNS_NAME_FORMATSIZE];
char domainbuf[DNS_NAME_FORMATSIZE];
char addrbuf[ISC_SOCKADDR_FORMATSIZE];
char classbuf[64];
char typebuf[64];
dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
dns_rdatatype_format(fctx->type, typebuf, sizeof(typebuf));
dns_rdataclass_format(res->rdclass, classbuf,
sizeof(classbuf));
isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf,
sizeof(addrbuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DELEGATION_ONLY,
DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
"enforced delegation-only for '%s' (%s/%s/%s) "
"from %s",
domainbuf, namebuf, typebuf, classbuf, addrbuf);
}
if ((res->options & DNS_RESOLVER_CHECKNAMES) != 0)
checknames(rmessage);
/*
* Clear cache bits.
*/
FCTX_ATTR_CLR(fctx, FCTX_ATTR_WANTNCACHE | FCTX_ATTR_WANTCACHE);
/*
* Did we get any answers?
*/
if (rmessage->counts[DNS_SECTION_ANSWER] > 0 &&
(rmessage->rcode == dns_rcode_noerror ||
rmessage->rcode == dns_rcode_yxdomain ||
rmessage->rcode == dns_rcode_nxdomain)) {
/*
* [normal case]
* We've got answers. If it has an authoritative answer or an
* answer from a forwarder, we're done.
*/
if ((rmessage->flags & DNS_MESSAGEFLAG_AA) != 0 ||
ISFORWARDER(query->addrinfo))
{
result = answer_response(fctx, rmessage);
if (result != ISC_R_SUCCESS)
FCTXTRACE3("answer_response (AA/fwd)", result);
} else if (iscname(fctx, rmessage) &&
fctx->type != dns_rdatatype_any &&
fctx->type != dns_rdatatype_cname)
{
/*
* A BIND8 server could return a non-authoritative
* answer when a CNAME is followed. We should treat
* it as a valid answer.
*/
result = answer_response(fctx, rmessage);
if (result != ISC_R_SUCCESS)
FCTXTRACE3("answer_response (!ANY/!CNAME)",
result);
} else if (fctx->type != dns_rdatatype_ns &&
!betterreferral(fctx, rmessage)) {
/*
* Lame response !!!.
*/
result = answer_response(fctx, rmessage);
if (result != ISC_R_SUCCESS)
FCTXTRACE3("answer_response (!NS)", result);
} else {
if (fctx->type == dns_rdatatype_ns) {
/*
* A BIND 8 server could incorrectly return a
* non-authoritative answer to an NS query
* instead of a referral. Since this answer
* lacks the SIGs necessary to do DNSSEC
* validation, we must invoke the following
* special kludge to treat it as a referral.
*/
result = noanswer_response(fctx,
rmessage,
NULL,
LOOK_FOR_NS_IN_ANSWER);
if (result != ISC_R_SUCCESS)
FCTXTRACE3("noanswer_response (NS)",
result);
} else {
/*
* Some other servers may still somehow include
* an answer when it should return a referral
* with an empty answer. Check to see if we can
* treat this as a referral by ignoring the
* answer. Further more, there may be an
* implementation that moves A/AAAA glue records
* to the answer section for that type of
* delegation when the query is for that glue
* record. LOOK_FOR_GLUE_IN_ANSWER will handle
* such a corner case.
*/
result = noanswer_response(fctx,
rmessage,
NULL,
LOOK_FOR_GLUE_IN_ANSWER);
if (result != ISC_R_SUCCESS)
FCTXTRACE3("noanswer_response", result);
}
if (result != DNS_R_DELEGATION) {
/*
* At this point, AA is not set, the response
* is not a referral, and the server is not a
* forwarder. It is technically lame and it's
* easier to treat it as such than to figure out
* some more elaborate course of action.
*/
broken_server = DNS_R_LAME;
keep_trying = true;
goto done;
}
goto force_referral;
}
if (result != ISC_R_SUCCESS) {
if (result == DNS_R_FORMERR)
keep_trying = true;
goto done;
}
} else if (rmessage->counts[DNS_SECTION_AUTHORITY] > 0 ||
rmessage->rcode == dns_rcode_noerror ||
rmessage->rcode == dns_rcode_nxdomain) {
/*
* NXDOMAIN, NXRDATASET, or referral.
*/
result = noanswer_response(fctx, rmessage, NULL, 0);
switch (result) {
case ISC_R_SUCCESS:
case DNS_R_CHASEDSSERVERS:
break;
case DNS_R_DELEGATION:
force_referral:
/*
* We don't have the answer, but we know a better
* place to look.
*/
get_nameservers = true;
keep_trying = true;
/*
* We have a new set of name servers, and it
* has not experienced any restarts yet.
*/
fctx->restarts = 0;
/*
* Update local statistics counters collected for each
* new zone.
*/
fctx->referrals++;
fctx->querysent = 0;
fctx->lamecount = 0;
fctx->quotacount = 0;
fctx->neterr = 0;
fctx->badresp = 0;
fctx->adberr = 0;
result = ISC_R_SUCCESS;
break;
default:
/*
* Something has gone wrong.
*/
if (result == DNS_R_FORMERR)
keep_trying = true;
FCTXTRACE3("noanswer_response", result);
goto done;
}
} else {
/*
* The server is insane.
*/
/* XXXRTH Log */
broken_server = DNS_R_UNEXPECTEDRCODE;
keep_trying = true;
FCTXTRACE("broken server: unexpected rcode");
goto done;
}
/*
* Follow additional section data chains.
*/
chase_additional(fctx, rmessage);
/*
* Cache the cacheable parts of the rmessage. This may also cause
* work to be queued to the DNSSEC validator.
*/
if (WANTCACHE(fctx)) {
result = cache_message(fctx, rmessage, query->addrinfo,
now);
if (result != ISC_R_SUCCESS) {
FCTXTRACE3("cache_message complete", result);
goto done;
}
}
/*
* Ncache the negatively cacheable parts of the rmessage. This may
* also cause work to be queued to the DNSSEC validator.
*/
if (WANTNCACHE(fctx)) {
dns_rdatatype_t covers;
/*
* Cache DS NXDOMAIN separately to other types.
*/
if (rmessage->rcode == dns_rcode_nxdomain &&
fctx->type != dns_rdatatype_ds)
covers = dns_rdatatype_any;
else
covers = fctx->type;
/*
* Cache any negative cache entries in the rmessage.
*/
result = ncache_message(fctx, rmessage, query->addrinfo, covers, now);
if (result != ISC_R_SUCCESS)
FCTXTRACE3("ncache_message complete", result);
}
done:
/*
* Remember the query's addrinfo, in case we need to mark the
* server as broken.
*/
addrinfo = query->addrinfo;
FCTXTRACE4("query canceled in response(); ",
no_response ? "no response" : "responding",
result);
/*
* Cancel the query.
*
* XXXRTH Don't cancel the query if waiting for validation?
*/
if (!nextitem)
fctx_cancelquery(&query, &devent, finish,
no_response, false);
#ifdef ENABLE_AFL
if (dns_fuzzing_resolver && (keep_trying || resend)) {
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
goto cleanup_rmessage;
} else
#endif
if (keep_trying) {
if (result == DNS_R_FORMERR)
broken_server = DNS_R_FORMERR;
if (broken_server != ISC_R_SUCCESS) {
/*
* Add this server to the list of bad servers for
* this fctx.
*/
add_bad(fctx, rmessage, addrinfo,
broken_server, broken_type);
}
if (get_nameservers) {
dns_name_t *name;
fname = dns_fixedname_initname(&foundname);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
goto detach_rmessage;
}
findoptions = 0;
if (dns_rdatatype_atparent(fctx->type))
findoptions |= DNS_DBFIND_NOEXACT;
if ((options & DNS_FETCHOPT_UNSHARED) == 0)
name = &fctx->name;
else
name = &fctx->domain;
result = dns_view_findzonecut(res->view,
name, fname,
now, findoptions,
true,
&fctx->nameservers,
NULL);
if (result != ISC_R_SUCCESS) {
FCTXTRACE("couldn't find a zonecut");
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
goto detach_rmessage;
}
if (!dns_name_issubdomain(fname, &fctx->domain)) {
/*
* The best nameservers are now above our
* QDOMAIN.
*/
FCTXTRACE("nameservers now above QDOMAIN");
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
goto detach_rmessage;
}
fcount_decr(fctx);
dns_name_free(&fctx->domain, fctx->mctx);
dns_name_init(&fctx->domain, NULL);
result = dns_name_dup(fname, fctx->mctx, &fctx->domain);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
goto detach_rmessage;
}
result = fcount_incr(fctx, true);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
goto detach_rmessage;
}
fctx->ns_ttl = fctx->nameservers.ttl;
fctx->ns_ttl_ok = true;
fctx_cancelqueries(fctx, true, false);
fctx_cleanupfinds(fctx);
fctx_cleanupaltfinds(fctx);
fctx_cleanupforwaddrs(fctx);
fctx_cleanupaltaddrs(fctx);
}
/*
* Try again.
*/
fctx_try(fctx, !get_nameservers, false);
} else if (resend) {
/*
* Resend (probably with changed options).
*/
FCTXTRACE("resend");
inc_stats(res, dns_resstatscounter_retry);
bucketnum = fctx->bucketnum;
fctx_increference(fctx);
result = fctx_query(fctx, addrinfo, options);
if (result != ISC_R_SUCCESS) {
fctx_done(fctx, result, __LINE__);
LOCK(&res->buckets[bucketnum].lock);
bucket_empty = fctx_decreference(fctx);
UNLOCK(&res->buckets[bucketnum].lock);
if (bucket_empty)
empty_bucket(res);
}
} else if (nextitem) {
/*
* Wait for next item.
*/
FCTXTRACE("nextitem");
inc_stats(fctx->res, dns_resstatscounter_nextitem);
INSIST(query->dispentry != NULL);
dns_message_reset(query->rmessage, DNS_MESSAGE_INTENTPARSE);
result = dns_dispatch_getnext(query->dispentry, &devent);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result, __LINE__);
} else if (result == ISC_R_SUCCESS && !HAVE_ANSWER(fctx)) {
/*
* All has gone well so far, but we are waiting for the
* DNSSEC validator to validate the answer.
*/
FCTXTRACE("wait for validator");
fctx_cancelqueries(fctx, true, false);
/*
* We must not retransmit while the validator is working;
* it has references to the current rmessage.
*/
result = fctx_stopidletimer(fctx);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result, __LINE__);
} else if (result == DNS_R_CHASEDSSERVERS) {
unsigned int n;
add_bad(fctx, rmessage, addrinfo, result, broken_type);
fctx_cancelqueries(fctx, true, false);
fctx_cleanupfinds(fctx);
fctx_cleanupforwaddrs(fctx);
n = dns_name_countlabels(&fctx->name);
dns_name_getlabelsequence(&fctx->name, 1, n - 1, &fctx->nsname);
FCTXTRACE("suspending DS lookup to find parent's NS records");
result = dns_resolver_createfetch(res, &fctx->nsname,
dns_rdatatype_ns,
NULL, NULL, NULL,
fctx->options, task,
resume_dslookup, fctx,
&fctx->nsrrset, NULL,
&fctx->nsfetch);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result, __LINE__);
else {
fctx_increference(fctx);
result = fctx_stopidletimer(fctx);
if (result != ISC_R_SUCCESS)
fctx_done(fctx, result, __LINE__);
}
} else {
/*
* We're done.
*/
fctx_done(fctx, result, __LINE__);
}
detach_rmessage:
dns_message_detach(&rmessage);
}
/***
*** Resolver Methods
***/
static void
destroy(dns_resolver_t *res) {
unsigned int i;
alternate_t *a;
REQUIRE(res->references == 0);
REQUIRE(!res->priming);
REQUIRE(res->primefetch == NULL);
RTRACE("destroy");
INSIST(res->nfctx == 0);
DESTROYLOCK(&res->spill_lock);
DESTROYLOCK(&res->primelock);
DESTROYLOCK(&res->nlock);
DESTROYLOCK(&res->lock);
for (i = 0; i < res->nbuckets; i++) {
INSIST(ISC_LIST_EMPTY(res->buckets[i].fctxs));
isc_task_shutdown(res->buckets[i].task);
isc_task_detach(&res->buckets[i].task);
DESTROYLOCK(&res->buckets[i].lock);
isc_mem_detach(&res->buckets[i].mctx);
}
isc_mem_put(res->mctx, res->buckets,
res->nbuckets * sizeof(fctxbucket_t));
for (i = 0; i < RES_DOMAIN_BUCKETS; i++) {
INSIST(ISC_LIST_EMPTY(res->dbuckets[i].list));
isc_mem_detach(&res->dbuckets[i].mctx);
DESTROYLOCK(&res->dbuckets[i].lock);
}
isc_mem_put(res->mctx, res->dbuckets,
RES_DOMAIN_BUCKETS * sizeof(zonebucket_t));
if (res->dispatches4 != NULL)
dns_dispatchset_destroy(&res->dispatches4);
if (res->dispatches6 != NULL)
dns_dispatchset_destroy(&res->dispatches6);
while ((a = ISC_LIST_HEAD(res->alternates)) != NULL) {
ISC_LIST_UNLINK(res->alternates, a, link);
if (!a->isaddress)
dns_name_free(&a->_u._n.name, res->mctx);
isc_mem_put(res->mctx, a, sizeof(*a));
}
dns_resolver_reset_algorithms(res);
dns_resolver_reset_ds_digests(res);
dns_badcache_destroy(&res->badcache);
dns_resolver_resetmustbesecure(res);
#if USE_ALGLOCK
isc_rwlock_destroy(&res->alglock);
#endif
#if USE_MBSLOCK
isc_rwlock_destroy(&res->mbslock);
#endif
isc_timer_detach(&res->spillattimer);
res->magic = 0;
isc_mem_put(res->mctx, res, sizeof(*res));
}
static void
send_shutdown_events(dns_resolver_t *res) {
isc_event_t *event, *next_event;
isc_task_t *etask;
/*
* Caller must be holding the resolver lock.
*/
for (event = ISC_LIST_HEAD(res->whenshutdown);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, ev_link);
ISC_LIST_UNLINK(res->whenshutdown, event, ev_link);
etask = event->ev_sender;
event->ev_sender = res;
isc_task_sendanddetach(&etask, &event);
}
}
static void
empty_bucket(dns_resolver_t *res) {
RTRACE("empty_bucket");
LOCK(&res->lock);
INSIST(res->activebuckets > 0);
res->activebuckets--;
if (res->activebuckets == 0)
send_shutdown_events(res);
UNLOCK(&res->lock);
}
static void
spillattimer_countdown(isc_task_t *task, isc_event_t *event) {
dns_resolver_t *res = event->ev_arg;
isc_result_t result;
unsigned int count;
bool logit = false;
REQUIRE(VALID_RESOLVER(res));
UNUSED(task);
LOCK(&res->lock);
INSIST(!res->exiting);
LOCK(&res->spill_lock);
if (res->spillat > res->spillatmin) {
res->spillat--;
logit = true;
}
if (res->spillat <= res->spillatmin) {
result = isc_timer_reset(res->spillattimer,
isc_timertype_inactive, NULL,
NULL, true);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
}
count = res->spillat;
UNLOCK(&res->spill_lock);
UNLOCK(&res->lock);
if (logit)
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
"clients-per-query decreased to %u", count);
isc_event_free(&event);
}
isc_result_t
dns_resolver_create(dns_view_t *view,
isc_taskmgr_t *taskmgr,
unsigned int ntasks, unsigned int ndisp,
isc_socketmgr_t *socketmgr,
isc_timermgr_t *timermgr,
unsigned int options,
dns_dispatchmgr_t *dispatchmgr,
dns_dispatch_t *dispatchv4,
dns_dispatch_t *dispatchv6,
dns_resolver_t **resp)
{
dns_resolver_t *res;
isc_result_t result = ISC_R_SUCCESS;
unsigned int i, buckets_created = 0, dbuckets_created = 0;
isc_task_t *task = NULL;
char name[16];
unsigned dispattr;
/*
* Create a resolver.
*/
REQUIRE(DNS_VIEW_VALID(view));
REQUIRE(ntasks > 0);
REQUIRE(ndisp > 0);
REQUIRE(resp != NULL && *resp == NULL);
REQUIRE(dispatchmgr != NULL);
REQUIRE(dispatchv4 != NULL || dispatchv6 != NULL);
res = isc_mem_get(view->mctx, sizeof(*res));
if (res == NULL)
return (ISC_R_NOMEMORY);
RTRACE("create");
res->mctx = view->mctx;
res->rdclass = view->rdclass;
res->socketmgr = socketmgr;
res->timermgr = timermgr;
res->taskmgr = taskmgr;
res->dispatchmgr = dispatchmgr;
res->view = view;
res->options = options;
res->lame_ttl = 0;
ISC_LIST_INIT(res->alternates);
res->udpsize = RECV_BUFFER_SIZE;
res->algorithms = NULL;
res->digests = NULL;
res->badcache = NULL;
result = dns_badcache_init(res->mctx, DNS_RESOLVER_BADCACHESIZE,
&res->badcache);
if (result != ISC_R_SUCCESS) {
goto cleanup_res;
}
res->mustbesecure = NULL;
res->spillatmin = res->spillat = 10;
res->spillatmax = 100;
res->spillattimer = NULL;
res->zspill = 0;
res->zero_no_soa_ttl = false;
res->query_timeout = DEFAULT_QUERY_TIMEOUT;
res->maxdepth = DEFAULT_RECURSION_DEPTH;
res->maxqueries = DEFAULT_MAX_QUERIES;
res->quotaresp[dns_quotatype_zone] = DNS_R_DROP;
res->quotaresp[dns_quotatype_server] = DNS_R_SERVFAIL;
res->nbuckets = ntasks;
if (view->resstats != NULL)
isc_stats_set(view->resstats, ntasks,
dns_resstatscounter_buckets);
res->activebuckets = ntasks;
res->buckets = isc_mem_get(view->mctx,
ntasks * sizeof(fctxbucket_t));
if (res->buckets == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup_badcache;
}
for (i = 0; i < ntasks; i++) {
result = isc_mutex_init(&res->buckets[i].lock);
if (result != ISC_R_SUCCESS)
goto cleanup_buckets;
res->buckets[i].task = NULL;
result = isc_task_create(taskmgr, 0, &res->buckets[i].task);
if (result != ISC_R_SUCCESS) {
DESTROYLOCK(&res->buckets[i].lock);
goto cleanup_buckets;
}
res->buckets[i].mctx = NULL;
snprintf(name, sizeof(name), "res%u", i);
#ifdef ISC_PLATFORM_USETHREADS
/*
* Use a separate memory context for each bucket to reduce
* contention among multiple threads. Do this only when
* enabling threads because it will be require more memory.
*/
result = isc_mem_create(0, 0, &res->buckets[i].mctx);
if (result != ISC_R_SUCCESS) {
isc_task_detach(&res->buckets[i].task);
DESTROYLOCK(&res->buckets[i].lock);
goto cleanup_buckets;
}
isc_mem_setname(res->buckets[i].mctx, name, NULL);
#else
isc_mem_attach(view->mctx, &res->buckets[i].mctx);
#endif
isc_task_setname(res->buckets[i].task, name, res);
ISC_LIST_INIT(res->buckets[i].fctxs);
res->buckets[i].exiting = false;
buckets_created++;
}
res->dbuckets = isc_mem_get(view->mctx,
RES_DOMAIN_BUCKETS * sizeof(zonebucket_t));
if (res->dbuckets == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup_buckets;
}
for (i = 0; i < RES_DOMAIN_BUCKETS; i++) {
ISC_LIST_INIT(res->dbuckets[i].list);
res->dbuckets[i].mctx = NULL;
isc_mem_attach(view->mctx, &res->dbuckets[i].mctx);
result = isc_mutex_init(&res->dbuckets[i].lock);
if (result != ISC_R_SUCCESS) {
isc_mem_detach(&res->dbuckets[i].mctx);
goto cleanup_dbuckets;
}
dbuckets_created++;
}
res->dispatches4 = NULL;
if (dispatchv4 != NULL) {
dns_dispatchset_create(view->mctx, socketmgr, taskmgr,
dispatchv4, &res->dispatches4, ndisp);
dispattr = dns_dispatch_getattributes(dispatchv4);
res->exclusivev4 = (dispattr & DNS_DISPATCHATTR_EXCLUSIVE);
}
res->dispatches6 = NULL;
if (dispatchv6 != NULL) {
dns_dispatchset_create(view->mctx, socketmgr, taskmgr,
dispatchv6, &res->dispatches6, ndisp);
dispattr = dns_dispatch_getattributes(dispatchv6);
res->exclusivev6 = (dispattr & DNS_DISPATCHATTR_EXCLUSIVE);
}
res->querydscp4 = -1;
res->querydscp6 = -1;
res->references = 1;
res->exiting = false;
res->frozen = false;
ISC_LIST_INIT(res->whenshutdown);
res->priming = false;
res->primefetch = NULL;
res->nfctx = 0;
result = isc_mutex_init(&res->lock);
if (result != ISC_R_SUCCESS)
goto cleanup_dispatches;
result = isc_mutex_init(&res->nlock);
if (result != ISC_R_SUCCESS)
goto cleanup_lock;
result = isc_mutex_init(&res->primelock);
if (result != ISC_R_SUCCESS)
goto cleanup_nlock;
result = isc_mutex_init(&res->spill_lock);
if (result != ISC_R_SUCCESS)
goto cleanup_primelock;
task = NULL;
result = isc_task_create(taskmgr, 0, &task);
if (result != ISC_R_SUCCESS)
goto cleanup_spill_lock;
isc_task_setname(task, "resolver_task", NULL);
result = isc_timer_create(timermgr, isc_timertype_inactive, NULL, NULL,
task, spillattimer_countdown, res,
&res->spillattimer);
isc_task_detach(&task);
if (result != ISC_R_SUCCESS)
goto cleanup_spill_lock;
#if USE_ALGLOCK
result = isc_rwlock_init(&res->alglock, 0, 0);
if (result != ISC_R_SUCCESS)
goto cleanup_spillattimer;
#endif
#if USE_MBSLOCK
result = isc_rwlock_init(&res->mbslock, 0, 0);
if (result != ISC_R_SUCCESS)
#if USE_ALGLOCK
goto cleanup_alglock;
#else
goto cleanup_spillattimer;
#endif
#endif
res->magic = RES_MAGIC;
*resp = res;
return (ISC_R_SUCCESS);
#if USE_ALGLOCK && USE_MBSLOCK
cleanup_alglock:
isc_rwlock_destroy(&res->alglock);
#endif
#if USE_ALGLOCK || USE_MBSLOCK
cleanup_spillattimer:
isc_timer_detach(&res->spillattimer);
#endif
cleanup_spill_lock:
DESTROYLOCK(&res->spill_lock);
cleanup_primelock:
DESTROYLOCK(&res->primelock);
cleanup_nlock:
DESTROYLOCK(&res->nlock);
cleanup_lock:
DESTROYLOCK(&res->lock);
cleanup_dispatches:
if (res->dispatches6 != NULL)
dns_dispatchset_destroy(&res->dispatches6);
if (res->dispatches4 != NULL)
dns_dispatchset_destroy(&res->dispatches4);
cleanup_dbuckets:
for (i = 0; i < dbuckets_created; i++) {
DESTROYLOCK(&res->dbuckets[i].lock);
isc_mem_detach(&res->dbuckets[i].mctx);
}
isc_mem_put(view->mctx, res->dbuckets,
RES_DOMAIN_BUCKETS * sizeof(zonebucket_t));
cleanup_buckets:
for (i = 0; i < buckets_created; i++) {
isc_mem_detach(&res->buckets[i].mctx);
DESTROYLOCK(&res->buckets[i].lock);
isc_task_shutdown(res->buckets[i].task);
isc_task_detach(&res->buckets[i].task);
}
isc_mem_put(view->mctx, res->buckets,
res->nbuckets * sizeof(fctxbucket_t));
cleanup_badcache:
dns_badcache_destroy(&res->badcache);
cleanup_res:
isc_mem_put(view->mctx, res, sizeof(*res));
return (result);
}
static void
prime_done(isc_task_t *task, isc_event_t *event) {
dns_resolver_t *res;
dns_fetchevent_t *fevent;
dns_fetch_t *fetch;
dns_db_t *db = NULL;
REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
fevent = (dns_fetchevent_t *)event;
res = event->ev_arg;
REQUIRE(VALID_RESOLVER(res));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
"resolver priming query complete");
UNUSED(task);
LOCK(&res->lock);
INSIST(res->priming);
res->priming = false;
LOCK(&res->primelock);
fetch = res->primefetch;
res->primefetch = NULL;
UNLOCK(&res->primelock);
UNLOCK(&res->lock);
if (fevent->result == ISC_R_SUCCESS &&
res->view->cache != NULL && res->view->hints != NULL) {
dns_cache_attachdb(res->view->cache, &db);
dns_root_checkhints(res->view, res->view->hints, db);
dns_db_detach(&db);
}
if (fevent->node != NULL)
dns_db_detachnode(fevent->db, &fevent->node);
if (fevent->db != NULL)
dns_db_detach(&fevent->db);
if (dns_rdataset_isassociated(fevent->rdataset))
dns_rdataset_disassociate(fevent->rdataset);
INSIST(fevent->sigrdataset == NULL);
isc_mem_put(res->mctx, fevent->rdataset, sizeof(*fevent->rdataset));
isc_event_free(&event);
dns_resolver_destroyfetch(&fetch);
}
void
dns_resolver_prime(dns_resolver_t *res) {
bool want_priming = false;
dns_rdataset_t *rdataset;
isc_result_t result;
REQUIRE(VALID_RESOLVER(res));
REQUIRE(res->frozen);
RTRACE("dns_resolver_prime");
LOCK(&res->lock);
if (!res->exiting && !res->priming) {
INSIST(res->primefetch == NULL);
res->priming = true;
want_priming = true;
}
UNLOCK(&res->lock);
if (want_priming) {
/*
* To avoid any possible recursive locking problems, we
* start the priming fetch like any other fetch, and holding
* no resolver locks. No one else will try to start it
* because we're the ones who set res->priming to true.
* Any other callers of dns_resolver_prime() while we're
* running will see that res->priming is already true and
* do nothing.
*/
RTRACE("priming");
rdataset = isc_mem_get(res->mctx, sizeof(*rdataset));
if (rdataset == NULL) {
LOCK(&res->lock);
INSIST(res->priming);
INSIST(res->primefetch == NULL);
res->priming = false;
UNLOCK(&res->lock);
return;
}
dns_rdataset_init(rdataset);
LOCK(&res->primelock);
result = dns_resolver_createfetch(res, dns_rootname,
dns_rdatatype_ns,
NULL, NULL, NULL,
DNS_FETCHOPT_NOFORWARD,
res->buckets[0].task,
prime_done,
res, rdataset, NULL,
&res->primefetch);
UNLOCK(&res->primelock);
if (result != ISC_R_SUCCESS) {
isc_mem_put(res->mctx, rdataset, sizeof(*rdataset));
LOCK(&res->lock);
INSIST(res->priming);
res->priming = false;
UNLOCK(&res->lock);
}
}
}
void
dns_resolver_freeze(dns_resolver_t *res) {
/*
* Freeze resolver.
*/
REQUIRE(VALID_RESOLVER(res));
res->frozen = true;
}
void
dns_resolver_attach(dns_resolver_t *source, dns_resolver_t **targetp) {
REQUIRE(VALID_RESOLVER(source));
REQUIRE(targetp != NULL && *targetp == NULL);
RRTRACE(source, "attach");
LOCK(&source->lock);
REQUIRE(!source->exiting);
INSIST(source->references > 0);
source->references++;
INSIST(source->references != 0);
UNLOCK(&source->lock);
*targetp = source;
}
void
dns_resolver_whenshutdown(dns_resolver_t *res, isc_task_t *task,
isc_event_t **eventp)
{
isc_task_t *tclone;
isc_event_t *event;
REQUIRE(VALID_RESOLVER(res));
REQUIRE(eventp != NULL);
event = *eventp;
*eventp = NULL;
LOCK(&res->lock);
if (res->exiting && res->activebuckets == 0) {
/*
* We're already shutdown. Send the event.
*/
event->ev_sender = res;
isc_task_send(task, &event);
} else {
tclone = NULL;
isc_task_attach(task, &tclone);
event->ev_sender = tclone;
ISC_LIST_APPEND(res->whenshutdown, event, ev_link);
}
UNLOCK(&res->lock);
}
void
dns_resolver_shutdown(dns_resolver_t *res) {
unsigned int i;
fetchctx_t *fctx;
isc_result_t result;
REQUIRE(VALID_RESOLVER(res));
RTRACE("shutdown");
LOCK(&res->lock);
if (!res->exiting) {
RTRACE("exiting");
res->exiting = true;
for (i = 0; i < res->nbuckets; i++) {
LOCK(&res->buckets[i].lock);
for (fctx = ISC_LIST_HEAD(res->buckets[i].fctxs);
fctx != NULL;
fctx = ISC_LIST_NEXT(fctx, link))
fctx_shutdown(fctx);
if (res->dispatches4 != NULL && !res->exclusivev4) {
dns_dispatchset_cancelall(res->dispatches4,
res->buckets[i].task);
}
if (res->dispatches6 != NULL && !res->exclusivev6) {
dns_dispatchset_cancelall(res->dispatches6,
res->buckets[i].task);
}
res->buckets[i].exiting = true;
if (ISC_LIST_EMPTY(res->buckets[i].fctxs)) {
INSIST(res->activebuckets > 0);
res->activebuckets--;
}
UNLOCK(&res->buckets[i].lock);
}
if (res->activebuckets == 0)
send_shutdown_events(res);
result = isc_timer_reset(res->spillattimer,
isc_timertype_inactive, NULL,
NULL, true);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
}
UNLOCK(&res->lock);
}
void
dns_resolver_detach(dns_resolver_t **resp) {
dns_resolver_t *res;
bool need_destroy = false;
REQUIRE(resp != NULL);
res = *resp;
REQUIRE(VALID_RESOLVER(res));
RTRACE("detach");
LOCK(&res->lock);
INSIST(res->references > 0);
res->references--;
if (res->references == 0) {
INSIST(res->exiting && res->activebuckets == 0);
need_destroy = true;
}
UNLOCK(&res->lock);
if (need_destroy)
destroy(res);
*resp = NULL;
}
static inline bool
fctx_match(fetchctx_t *fctx, dns_name_t *name, dns_rdatatype_t type,
unsigned int options)
{
/*
* Don't match fetch contexts that are shutting down.
*/
if (fctx->cloned || fctx->state == fetchstate_done ||
ISC_LIST_EMPTY(fctx->events))
return (false);
if (fctx->type != type || fctx->options != options)
return (false);
return (dns_name_equal(&fctx->name, name));
}
static inline void
log_fetch(dns_name_t *name, dns_rdatatype_t type) {
char namebuf[DNS_NAME_FORMATSIZE];
char typebuf[DNS_RDATATYPE_FORMATSIZE];
int level = ISC_LOG_DEBUG(1);
/*
* If there's no chance of logging it, don't render (format) the
* name and RDATA type (further below), and return early.
*/
if (! isc_log_wouldlog(dns_lctx, level))
return;
dns_name_format(name, namebuf, sizeof(namebuf));
dns_rdatatype_format(type, typebuf, sizeof(typebuf));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
DNS_LOGMODULE_RESOLVER, level,
"fetch: %s/%s", namebuf, typebuf);
}
isc_result_t
dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
dns_rdatatype_t type,
dns_name_t *domain, dns_rdataset_t *nameservers,
dns_forwarders_t *forwarders,
unsigned int options, isc_task_t *task,
isc_taskaction_t action, void *arg,
dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset,
dns_fetch_t **fetchp)
{
return (dns_resolver_createfetch3(res, name, type, domain,
nameservers, forwarders, NULL, 0,
options, 0, NULL, task, action, arg,
rdataset, sigrdataset, fetchp));
}
isc_result_t
dns_resolver_createfetch2(dns_resolver_t *res, dns_name_t *name,
dns_rdatatype_t type,
dns_name_t *domain, dns_rdataset_t *nameservers,
dns_forwarders_t *forwarders,
isc_sockaddr_t *client, dns_messageid_t id,
unsigned int options, isc_task_t *task,
isc_taskaction_t action, void *arg,
dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset,
dns_fetch_t **fetchp)
{
return (dns_resolver_createfetch3(res, name, type, domain,
nameservers, forwarders, client, id,
options, 0, NULL, task, action, arg,
rdataset, sigrdataset, fetchp));
}
isc_result_t
dns_resolver_createfetch3(dns_resolver_t *res, dns_name_t *name,
dns_rdatatype_t type,
dns_name_t *domain, dns_rdataset_t *nameservers,
dns_forwarders_t *forwarders,
isc_sockaddr_t *client, dns_messageid_t id,
unsigned int options, unsigned int depth,
isc_counter_t *qc, isc_task_t *task,
isc_taskaction_t action, void *arg,
dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset,
dns_fetch_t **fetchp)
{
dns_fetch_t *fetch;
fetchctx_t *fctx = NULL;
isc_result_t result = ISC_R_SUCCESS;
unsigned int bucketnum;
bool new_fctx = false;
isc_event_t *event;
unsigned int count = 0;
unsigned int spillat;
unsigned int spillatmin;
bool dodestroy = false;
UNUSED(forwarders);
REQUIRE(VALID_RESOLVER(res));
REQUIRE(res->frozen);
/* XXXRTH Check for meta type */
if (domain != NULL) {
REQUIRE(DNS_RDATASET_VALID(nameservers));
REQUIRE(nameservers->type == dns_rdatatype_ns);
} else
REQUIRE(nameservers == NULL);
REQUIRE(forwarders == NULL);
REQUIRE(!dns_rdataset_isassociated(rdataset));
REQUIRE(sigrdataset == NULL ||
!dns_rdataset_isassociated(sigrdataset));
REQUIRE(fetchp != NULL && *fetchp == NULL);
log_fetch(name, type);
/*
* XXXRTH use a mempool?
*/
fetch = isc_mem_get(res->mctx, sizeof(*fetch));
if (fetch == NULL)
return (ISC_R_NOMEMORY);
fetch->mctx = NULL;
isc_mem_attach(res->mctx, &fetch->mctx);
bucketnum = dns_name_fullhash(name, false) % res->nbuckets;
LOCK(&res->spill_lock);
spillat = res->spillat;
spillatmin = res->spillatmin;
UNLOCK(&res->spill_lock);
LOCK(&res->buckets[bucketnum].lock);
if (res->buckets[bucketnum].exiting) {
result = ISC_R_SHUTTINGDOWN;
goto unlock;
}
if ((options & DNS_FETCHOPT_UNSHARED) == 0) {
for (fctx = ISC_LIST_HEAD(res->buckets[bucketnum].fctxs);
fctx != NULL;
fctx = ISC_LIST_NEXT(fctx, link)) {
if (fctx_match(fctx, name, type, options))
break;
}
}
/*
* Is this a duplicate?
*/
if (fctx != NULL && client != NULL) {
dns_fetchevent_t *fevent;
for (fevent = ISC_LIST_HEAD(fctx->events);
fevent != NULL;
fevent = ISC_LIST_NEXT(fevent, ev_link)) {
if (fevent->client != NULL && fevent->id == id &&
isc_sockaddr_equal(fevent->client, client)) {
result = DNS_R_DUPLICATE;
goto unlock;
}
count++;
}
}
if (count >= spillatmin && spillatmin != 0) {
INSIST(fctx != NULL);
if (count >= spillat)
fctx->spilled = true;
if (fctx->spilled) {
result = DNS_R_DROP;
goto unlock;
}
}
if (fctx == NULL) {
result = fctx_create(res, name, type, domain, nameservers,
client, options, bucketnum, depth, qc,
&fctx);
if (result != ISC_R_SUCCESS)
goto unlock;
new_fctx = true;
} else if (fctx->depth > depth)
fctx->depth = depth;
result = fctx_join(fctx, task, client, id, action, arg,
rdataset, sigrdataset, fetch);
if (new_fctx) {
if (result == ISC_R_SUCCESS) {
/*
* Launch this fctx.
*/
event = &fctx->control_event;
ISC_EVENT_INIT(event, sizeof(*event), 0, NULL,
DNS_EVENT_FETCHCONTROL,
fctx_start, fctx, NULL,
NULL, NULL);
isc_task_send(res->buckets[bucketnum].task, &event);
} else {
/*
* We don't care about the result of fctx_unlink()
* since we know we're not exiting.
*/
(void)fctx_unlink(fctx);
dodestroy = true;
}
}
unlock:
UNLOCK(&res->buckets[bucketnum].lock);
if (dodestroy)
fctx_destroy(fctx);
if (result == ISC_R_SUCCESS) {
FTRACE("created");
*fetchp = fetch;
} else
isc_mem_putanddetach(&fetch->mctx, fetch, sizeof(*fetch));
return (result);
}
void
dns_resolver_cancelfetch(dns_fetch_t *fetch) {
fetchctx_t *fctx;
dns_resolver_t *res;
dns_fetchevent_t *event, *next_event;
isc_task_t *etask;
REQUIRE(DNS_FETCH_VALID(fetch));
fctx = fetch->private;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
FTRACE("cancelfetch");
LOCK(&res->buckets[fctx->bucketnum].lock);
/*
* Find the completion event for this fetch (as opposed
* to those for other fetches that have joined the same
* fctx) and send it with result = ISC_R_CANCELED.
*/
event = NULL;
if (fctx->state != fetchstate_done) {
for (event = ISC_LIST_HEAD(fctx->events);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, ev_link);
if (event->fetch == fetch) {
ISC_LIST_UNLINK(fctx->events, event, ev_link);
break;
}
}
}
if (event != NULL) {
etask = event->ev_sender;
event->ev_sender = fctx;
event->result = ISC_R_CANCELED;
isc_task_sendanddetach(&etask, ISC_EVENT_PTR(&event));
}
/*
* The fctx continues running even if no fetches remain;
* the answer is still cached.
*/
UNLOCK(&res->buckets[fctx->bucketnum].lock);
}
void
dns_resolver_destroyfetch(dns_fetch_t **fetchp) {
dns_fetch_t *fetch;
dns_resolver_t *res;
dns_fetchevent_t *event, *next_event;
fetchctx_t *fctx;
unsigned int bucketnum;
bool bucket_empty;
REQUIRE(fetchp != NULL);
fetch = *fetchp;
REQUIRE(DNS_FETCH_VALID(fetch));
fctx = fetch->private;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
FTRACE("destroyfetch");
bucketnum = fctx->bucketnum;
LOCK(&res->buckets[bucketnum].lock);
/*
* Sanity check: the caller should have gotten its event before
* trying to destroy the fetch.
*/
event = NULL;
if (fctx->state != fetchstate_done) {
for (event = ISC_LIST_HEAD(fctx->events);
event != NULL;
event = next_event) {
next_event = ISC_LIST_NEXT(event, ev_link);
RUNTIME_CHECK(event->fetch != fetch);
}
}
bucket_empty = fctx_decreference(fctx);
UNLOCK(&res->buckets[bucketnum].lock);
isc_mem_putanddetach(&fetch->mctx, fetch, sizeof(*fetch));
*fetchp = NULL;
if (bucket_empty)
empty_bucket(res);
}
void
dns_resolver_logfetch(dns_fetch_t *fetch, isc_log_t *lctx,
isc_logcategory_t *category, isc_logmodule_t *module,
int level, bool duplicateok)
{
fetchctx_t *fctx;
dns_resolver_t *res;
char domainbuf[DNS_NAME_FORMATSIZE];
REQUIRE(DNS_FETCH_VALID(fetch));
fctx = fetch->private;
REQUIRE(VALID_FCTX(fctx));
res = fctx->res;
LOCK(&res->buckets[fctx->bucketnum].lock);
INSIST(fctx->exitline >= 0);
if (!fctx->logged || duplicateok) {
dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
isc_log_write(lctx, category, module, level,
"fetch completed at %s:%d for %s in "
"%" PRIu64 "."
"%06" PRIu64 ": %s/%s "
"[domain:%s,referral:%u,restart:%u,qrysent:%u,"
"timeout:%u,lame:%u,quota:%u,neterr:%u,"
"badresp:%u,adberr:%u,findfail:%u,valfail:%u]",
__FILE__, fctx->exitline, fctx->info,
fctx->duration / US_PER_SEC,
fctx->duration % US_PER_SEC,
isc_result_totext(fctx->result),
isc_result_totext(fctx->vresult), domainbuf,
fctx->referrals, fctx->restarts,
fctx->querysent, fctx->timeouts,
fctx->lamecount, fctx->quotacount,
fctx->neterr, fctx->badresp, fctx->adberr,
fctx->findfail, fctx->valfail);
fctx->logged = true;
}
UNLOCK(&res->buckets[fctx->bucketnum].lock);
}
dns_dispatchmgr_t *
dns_resolver_dispatchmgr(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->dispatchmgr);
}
dns_dispatch_t *
dns_resolver_dispatchv4(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (dns_dispatchset_get(resolver->dispatches4));
}
dns_dispatch_t *
dns_resolver_dispatchv6(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (dns_dispatchset_get(resolver->dispatches6));
}
isc_socketmgr_t *
dns_resolver_socketmgr(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->socketmgr);
}
isc_taskmgr_t *
dns_resolver_taskmgr(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->taskmgr);
}
uint32_t
dns_resolver_getlamettl(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->lame_ttl);
}
void
dns_resolver_setlamettl(dns_resolver_t *resolver, uint32_t lame_ttl) {
REQUIRE(VALID_RESOLVER(resolver));
resolver->lame_ttl = lame_ttl;
}
unsigned int
dns_resolver_nrunning(dns_resolver_t *resolver) {
unsigned int n;
LOCK(&resolver->nlock);
n = resolver->nfctx;
UNLOCK(&resolver->nlock);
return (n);
}
isc_result_t
dns_resolver_addalternate(dns_resolver_t *resolver, isc_sockaddr_t *alt,
dns_name_t *name, in_port_t port) {
alternate_t *a;
isc_result_t result;
REQUIRE(VALID_RESOLVER(resolver));
REQUIRE(!resolver->frozen);
REQUIRE((alt == NULL) ^ (name == NULL));
a = isc_mem_get(resolver->mctx, sizeof(*a));
if (a == NULL)
return (ISC_R_NOMEMORY);
if (alt != NULL) {
a->isaddress = true;
a->_u.addr = *alt;
} else {
a->isaddress = false;
a->_u._n.port = port;
dns_name_init(&a->_u._n.name, NULL);
result = dns_name_dup(name, resolver->mctx, &a->_u._n.name);
if (result != ISC_R_SUCCESS) {
isc_mem_put(resolver->mctx, a, sizeof(*a));
return (result);
}
}
ISC_LINK_INIT(a, link);
ISC_LIST_APPEND(resolver->alternates, a, link);
return (ISC_R_SUCCESS);
}
void
dns_resolver_setudpsize(dns_resolver_t *resolver, uint16_t udpsize) {
REQUIRE(VALID_RESOLVER(resolver));
resolver->udpsize = udpsize;
}
uint16_t
dns_resolver_getudpsize(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->udpsize);
}
void
dns_resolver_flushbadcache(dns_resolver_t *resolver, dns_name_t *name) {
if (name != NULL)
dns_badcache_flushname(resolver->badcache, name);
else
dns_badcache_flush(resolver->badcache);
}
void
dns_resolver_flushbadnames(dns_resolver_t *resolver, dns_name_t *name) {
dns_badcache_flushtree(resolver->badcache, name);
}
void
dns_resolver_addbadcache(dns_resolver_t *resolver, dns_name_t *name,
dns_rdatatype_t type, isc_time_t *expire)
{
#ifdef ENABLE_AFL
if (!dns_fuzzing_resolver)
#endif
{
(void) dns_badcache_add(resolver->badcache, name, type,
false, 0, expire);
}
}
bool
dns_resolver_getbadcache(dns_resolver_t *resolver, dns_name_t *name,
dns_rdatatype_t type, isc_time_t *now)
{
return (dns_badcache_find(resolver->badcache, name, type, NULL, now));
}
void
dns_resolver_printbadcache(dns_resolver_t *resolver, FILE *fp) {
(void) dns_badcache_print(resolver->badcache, "Bad cache", fp);
}
static void
free_algorithm(void *node, void *arg) {
unsigned char *algorithms = node;
isc_mem_t *mctx = arg;
isc_mem_put(mctx, algorithms, *algorithms);
}
void
dns_resolver_reset_algorithms(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
#if USE_ALGLOCK
RWLOCK(&resolver->alglock, isc_rwlocktype_write);
#endif
if (resolver->algorithms != NULL)
dns_rbt_destroy(&resolver->algorithms);
#if USE_ALGLOCK
RWUNLOCK(&resolver->alglock, isc_rwlocktype_write);
#endif
}
isc_result_t
dns_resolver_disable_algorithm(dns_resolver_t *resolver, dns_name_t *name,
unsigned int alg)
{
unsigned int len, mask;
unsigned char *tmp;
unsigned char *algorithms;
isc_result_t result;
dns_rbtnode_t *node = NULL;
/*
* Whether an algorithm is disabled (or not) is stored in a
* per-name bitfield that is stored as the node data of an
* RBT.
*/
REQUIRE(VALID_RESOLVER(resolver));
if (alg > 255)
return (ISC_R_RANGE);
#if USE_ALGLOCK
RWLOCK(&resolver->alglock, isc_rwlocktype_write);
#endif
if (resolver->algorithms == NULL) {
result = dns_rbt_create(resolver->mctx, free_algorithm,
resolver->mctx, &resolver->algorithms);
if (result != ISC_R_SUCCESS)
goto cleanup;
}
len = alg/8 + 2;
mask = 1 << (alg%8);
result = dns_rbt_addnode(resolver->algorithms, name, &node);
if (result == ISC_R_SUCCESS || result == ISC_R_EXISTS) {
algorithms = node->data;
/*
* If algorithms is set, algorithms[0] contains its
* length.
*/
if (algorithms == NULL || len > *algorithms) {
/*
* If no bitfield exists in the node data, or if
* it is not long enough, allocate a new
* bitfield and copy the old (smaller) bitfield
* into it if one exists.
*/
tmp = isc_mem_get(resolver->mctx, len);
if (tmp == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup;
}
memset(tmp, 0, len);
if (algorithms != NULL)
memmove(tmp, algorithms, *algorithms);
tmp[len-1] |= mask;
/* 'tmp[0]' should contain the length of 'tmp'. */
*tmp = len;
node->data = tmp;
/* Free the older bitfield. */
if (algorithms != NULL)
isc_mem_put(resolver->mctx, algorithms,
*algorithms);
} else
algorithms[len-1] |= mask;
}
result = ISC_R_SUCCESS;
cleanup:
#if USE_ALGLOCK
RWUNLOCK(&resolver->alglock, isc_rwlocktype_write);
#endif
return (result);
}
bool
dns_resolver_algorithm_supported(dns_resolver_t *resolver, dns_name_t *name,
unsigned int alg)
{
unsigned int len, mask;
unsigned char *algorithms;
void *data = NULL;
isc_result_t result;
bool found = false;
REQUIRE(VALID_RESOLVER(resolver));
/*
* DH is unsupported for DNSKEYs, see RFC 4034 sec. A.1.
*/
if ((alg == DST_ALG_DH) || (alg == DST_ALG_INDIRECT))
return (false);
#if USE_ALGLOCK
RWLOCK(&resolver->alglock, isc_rwlocktype_read);
#endif
if (resolver->algorithms == NULL)
goto unlock;
result = dns_rbt_findname(resolver->algorithms, name, 0, NULL, &data);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
len = alg/8 + 2;
mask = 1 << (alg%8);
algorithms = data;
if (len <= *algorithms && (algorithms[len-1] & mask) != 0)
found = true;
}
unlock:
#if USE_ALGLOCK
RWUNLOCK(&resolver->alglock, isc_rwlocktype_read);
#endif
if (found)
return (false);
return (dst_algorithm_supported(alg));
}
static void
free_digest(void *node, void *arg) {
unsigned char *digests = node;
isc_mem_t *mctx = arg;
isc_mem_put(mctx, digests, *digests);
}
void
dns_resolver_reset_ds_digests(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
#if USE_ALGLOCK
RWLOCK(&resolver->alglock, isc_rwlocktype_write);
#endif
if (resolver->digests != NULL)
dns_rbt_destroy(&resolver->digests);
#if USE_ALGLOCK
RWUNLOCK(&resolver->alglock, isc_rwlocktype_write);
#endif
}
isc_result_t
dns_resolver_disable_ds_digest(dns_resolver_t *resolver, dns_name_t *name,
unsigned int digest_type)
{
unsigned int len, mask;
unsigned char *tmp;
unsigned char *digests;
isc_result_t result;
dns_rbtnode_t *node = NULL;
/*
* Whether a digest is disabled (or not) is stored in a per-name
* bitfield that is stored as the node data of an RBT.
*/
REQUIRE(VALID_RESOLVER(resolver));
if (digest_type > 255)
return (ISC_R_RANGE);
#if USE_ALGLOCK
RWLOCK(&resolver->alglock, isc_rwlocktype_write);
#endif
if (resolver->digests == NULL) {
result = dns_rbt_create(resolver->mctx, free_digest,
resolver->mctx, &resolver->digests);
if (result != ISC_R_SUCCESS)
goto cleanup;
}
len = digest_type/8 + 2;
mask = 1 << (digest_type%8);
result = dns_rbt_addnode(resolver->digests, name, &node);
if (result == ISC_R_SUCCESS || result == ISC_R_EXISTS) {
digests = node->data;
/* If digests is set, digests[0] contains its length. */
if (digests == NULL || len > *digests) {
/*
* If no bitfield exists in the node data, or if
* it is not long enough, allocate a new
* bitfield and copy the old (smaller) bitfield
* into it if one exists.
*/
tmp = isc_mem_get(resolver->mctx, len);
if (tmp == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup;
}
memset(tmp, 0, len);
if (digests != NULL)
memmove(tmp, digests, *digests);
tmp[len-1] |= mask;
/* tmp[0] should contain the length of 'tmp'. */
*tmp = len;
node->data = tmp;
/* Free the older bitfield. */
if (digests != NULL)
isc_mem_put(resolver->mctx, digests,
*digests);
} else
digests[len-1] |= mask;
}
result = ISC_R_SUCCESS;
cleanup:
#if USE_ALGLOCK
RWUNLOCK(&resolver->alglock, isc_rwlocktype_write);
#endif
return (result);
}
bool
dns_resolver_ds_digest_supported(dns_resolver_t *resolver, dns_name_t *name,
unsigned int digest_type)
{
unsigned int len, mask;
unsigned char *digests;
void *data = NULL;
isc_result_t result;
bool found = false;
REQUIRE(VALID_RESOLVER(resolver));
#if USE_ALGLOCK
RWLOCK(&resolver->alglock, isc_rwlocktype_read);
#endif
if (resolver->digests == NULL)
goto unlock;
result = dns_rbt_findname(resolver->digests, name, 0, NULL, &data);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
len = digest_type/8 + 2;
mask = 1 << (digest_type%8);
digests = data;
if (len <= *digests && (digests[len-1] & mask) != 0)
found = true;
}
unlock:
#if USE_ALGLOCK
RWUNLOCK(&resolver->alglock, isc_rwlocktype_read);
#endif
if (found)
return (false);
return (dst_ds_digest_supported(digest_type));
}
void
dns_resolver_resetmustbesecure(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
#if USE_MBSLOCK
RWLOCK(&resolver->mbslock, isc_rwlocktype_write);
#endif
if (resolver->mustbesecure != NULL)
dns_rbt_destroy(&resolver->mustbesecure);
#if USE_MBSLOCK
RWUNLOCK(&resolver->mbslock, isc_rwlocktype_write);
#endif
}
static bool yes = true, no = false;
isc_result_t
dns_resolver_setmustbesecure(dns_resolver_t *resolver, dns_name_t *name,
bool value)
{
isc_result_t result;
REQUIRE(VALID_RESOLVER(resolver));
#if USE_MBSLOCK
RWLOCK(&resolver->mbslock, isc_rwlocktype_write);
#endif
if (resolver->mustbesecure == NULL) {
result = dns_rbt_create(resolver->mctx, NULL, NULL,
&resolver->mustbesecure);
if (result != ISC_R_SUCCESS)
goto cleanup;
}
result = dns_rbt_addname(resolver->mustbesecure, name,
value ? &yes : &no);
cleanup:
#if USE_MBSLOCK
RWUNLOCK(&resolver->mbslock, isc_rwlocktype_write);
#endif
return (result);
}
bool
dns_resolver_getmustbesecure(dns_resolver_t *resolver, dns_name_t *name) {
void *data = NULL;
bool value = false;
isc_result_t result;
REQUIRE(VALID_RESOLVER(resolver));
#if USE_MBSLOCK
RWLOCK(&resolver->mbslock, isc_rwlocktype_read);
#endif
if (resolver->mustbesecure == NULL)
goto unlock;
result = dns_rbt_findname(resolver->mustbesecure, name, 0, NULL, &data);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
value = *(bool*)data;
unlock:
#if USE_MBSLOCK
RWUNLOCK(&resolver->mbslock, isc_rwlocktype_read);
#endif
return (value);
}
void
dns_resolver_getclientsperquery(dns_resolver_t *resolver, uint32_t *cur,
uint32_t *min, uint32_t *max)
{
REQUIRE(VALID_RESOLVER(resolver));
LOCK(&resolver->spill_lock);
if (cur != NULL)
*cur = resolver->spillat;
if (min != NULL)
*min = resolver->spillatmin;
if (max != NULL)
*max = resolver->spillatmax;
UNLOCK(&resolver->spill_lock);
}
void
dns_resolver_setclientsperquery(dns_resolver_t *resolver, uint32_t min,
uint32_t max)
{
REQUIRE(VALID_RESOLVER(resolver));
LOCK(&resolver->spill_lock);
resolver->spillatmin = resolver->spillat = min;
resolver->spillatmax = max;
UNLOCK(&resolver->spill_lock);
}
void
dns_resolver_setfetchesperzone(dns_resolver_t *resolver, uint32_t clients)
{
REQUIRE(VALID_RESOLVER(resolver));
LOCK(&resolver->spill_lock);
resolver->zspill = clients;
UNLOCK(&resolver->spill_lock);
}
bool
dns_resolver_getzeronosoattl(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->zero_no_soa_ttl);
}
void
dns_resolver_setzeronosoattl(dns_resolver_t *resolver, bool state) {
REQUIRE(VALID_RESOLVER(resolver));
resolver->zero_no_soa_ttl = state;
}
unsigned int
dns_resolver_getoptions(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->options);
}
unsigned int
dns_resolver_gettimeout(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->query_timeout);
}
void
dns_resolver_settimeout(dns_resolver_t *resolver, unsigned int seconds) {
REQUIRE(VALID_RESOLVER(resolver));
if (seconds == 0)
seconds = DEFAULT_QUERY_TIMEOUT;
if (seconds > MAXIMUM_QUERY_TIMEOUT)
seconds = MAXIMUM_QUERY_TIMEOUT;
if (seconds < MINIMUM_QUERY_TIMEOUT)
seconds = MINIMUM_QUERY_TIMEOUT;
resolver->query_timeout = seconds;
}
void
dns_resolver_setquerydscp4(dns_resolver_t *resolver, isc_dscp_t dscp) {
REQUIRE(VALID_RESOLVER(resolver));
resolver->querydscp4 = dscp;
}
isc_dscp_t
dns_resolver_getquerydscp4(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->querydscp4);
}
void
dns_resolver_setquerydscp6(dns_resolver_t *resolver, isc_dscp_t dscp) {
REQUIRE(VALID_RESOLVER(resolver));
resolver->querydscp6 = dscp;
}
isc_dscp_t
dns_resolver_getquerydscp6(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->querydscp6);
}
void
dns_resolver_setmaxdepth(dns_resolver_t *resolver, unsigned int maxdepth) {
REQUIRE(VALID_RESOLVER(resolver));
resolver->maxdepth = maxdepth;
}
unsigned int
dns_resolver_getmaxdepth(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->maxdepth);
}
void
dns_resolver_setmaxqueries(dns_resolver_t *resolver, unsigned int queries) {
REQUIRE(VALID_RESOLVER(resolver));
resolver->maxqueries = queries;
}
unsigned int
dns_resolver_getmaxqueries(dns_resolver_t *resolver) {
REQUIRE(VALID_RESOLVER(resolver));
return (resolver->maxqueries);
}
void
dns_resolver_dumpfetches(dns_resolver_t *resolver,
isc_statsformat_t format, FILE *fp)
{
int i;
REQUIRE(VALID_RESOLVER(resolver));
REQUIRE(fp != NULL);
REQUIRE(format == isc_statsformat_file);
for (i = 0; i < RES_DOMAIN_BUCKETS; i++) {
fctxcount_t *fc;
LOCK(&resolver->dbuckets[i].lock);
for (fc = ISC_LIST_HEAD(resolver->dbuckets[i].list);
fc != NULL;
fc = ISC_LIST_NEXT(fc, link))
{
dns_name_print(fc->domain, fp);
fprintf(fp, ": %u active (%u spilled, %u allowed)\n",
fc->count, fc->dropped, fc->allowed);
}
UNLOCK(&resolver->dbuckets[i].lock);
}
}
void
dns_resolver_setquotaresponse(dns_resolver_t *resolver,
dns_quotatype_t which, isc_result_t resp)
{
REQUIRE(VALID_RESOLVER(resolver));
REQUIRE(which == dns_quotatype_zone || which == dns_quotatype_server);
REQUIRE(resp == DNS_R_DROP || resp == DNS_R_SERVFAIL);
resolver->quotaresp[which] = resp;
}
isc_result_t
dns_resolver_getquotaresponse(dns_resolver_t *resolver, dns_quotatype_t which)
{
REQUIRE(VALID_RESOLVER(resolver));
REQUIRE(which == dns_quotatype_zone || which == dns_quotatype_server);
return (resolver->quotaresp[which]);
}