/* SPDX-License-Identifier: LGPL-2.1+ */
#include <sys/socket.h>
#include <errno.h>
#include "dns-type.h"
#include "parse-util.h"
#include "string-util.h"
typedef const struct {
uint16_t type;
const char *name;
} dns_type;
static const struct dns_type_name *
lookup_dns_type (register const char *str, register GPERF_LEN_TYPE len);
#include "dns_type-from-name.h"
#include "dns_type-to-name.h"
int dns_type_from_string(const char *s) {
const struct dns_type_name *sc;
assert(s);
sc = lookup_dns_type(s, strlen(s));
if (sc)
return sc->id;
s = startswith_no_case(s, "TYPE");
if (s) {
unsigned x;
if (safe_atou(s, &x) >= 0 &&
x <= UINT16_MAX)
return (int) x;
}
return _DNS_TYPE_INVALID;
}
bool dns_type_is_pseudo(uint16_t type) {
/* Checks whether the specified type is a "pseudo-type". What
* a "pseudo-type" precisely is, is defined only very weakly,
* but apparently entails all RR types that are not actually
* stored as RRs on the server and should hence also not be
* cached. We use this list primarily to validate NSEC type
* bitfields, and to verify what to cache. */
return IN_SET(type,
0, /* A Pseudo RR type, according to RFC 2931 */
DNS_TYPE_ANY,
DNS_TYPE_AXFR,
DNS_TYPE_IXFR,
DNS_TYPE_OPT,
DNS_TYPE_TSIG,
DNS_TYPE_TKEY
);
}
bool dns_class_is_pseudo(uint16_t class) {
return class == DNS_TYPE_ANY;
}
bool dns_type_is_valid_query(uint16_t type) {
/* The types valid as questions in packets */
return !IN_SET(type,
0,
DNS_TYPE_OPT,
DNS_TYPE_TSIG,
DNS_TYPE_TKEY,
/* RRSIG are technically valid as questions, but we refuse doing explicit queries for them, as
* they aren't really payload, but signatures for payload, and cannot be validated on their
* own. After all they are the signatures, and have no signatures of their own validating
* them. */
DNS_TYPE_RRSIG);
}
bool dns_type_is_zone_transer(uint16_t type) {
/* Zone transfers, either normal or incremental */
return IN_SET(type,
DNS_TYPE_AXFR,
DNS_TYPE_IXFR);
}
bool dns_type_is_valid_rr(uint16_t type) {
/* The types valid as RR in packets (but not necessarily
* stored on servers). */
return !IN_SET(type,
DNS_TYPE_ANY,
DNS_TYPE_AXFR,
DNS_TYPE_IXFR);
}
bool dns_class_is_valid_rr(uint16_t class) {
return class != DNS_CLASS_ANY;
}
bool dns_type_may_redirect(uint16_t type) {
/* The following record types should never be redirected using
* CNAME/DNAME RRs. See
* <https://tools.ietf.org/html/rfc4035#section-2.5>. */
if (dns_type_is_pseudo(type))
return false;
return !IN_SET(type,
DNS_TYPE_CNAME,
DNS_TYPE_DNAME,
DNS_TYPE_NSEC3,
DNS_TYPE_NSEC,
DNS_TYPE_RRSIG,
DNS_TYPE_NXT,
DNS_TYPE_SIG,
DNS_TYPE_KEY);
}
bool dns_type_may_wildcard(uint16_t type) {
/* The following records may not be expanded from wildcard RRsets */
if (dns_type_is_pseudo(type))
return false;
return !IN_SET(type,
DNS_TYPE_NSEC3,
DNS_TYPE_SOA,
/* Prohibited by https://tools.ietf.org/html/rfc4592#section-4.4 */
DNS_TYPE_DNAME);
}
bool dns_type_apex_only(uint16_t type) {
/* Returns true for all RR types that may only appear signed in a zone apex */
return IN_SET(type,
DNS_TYPE_SOA,
DNS_TYPE_NS, /* this one can appear elsewhere, too, but not signed */
DNS_TYPE_DNSKEY,
DNS_TYPE_NSEC3PARAM);
}
bool dns_type_is_dnssec(uint16_t type) {
return IN_SET(type,
DNS_TYPE_DS,
DNS_TYPE_DNSKEY,
DNS_TYPE_RRSIG,
DNS_TYPE_NSEC,
DNS_TYPE_NSEC3,
DNS_TYPE_NSEC3PARAM);
}
bool dns_type_is_obsolete(uint16_t type) {
return IN_SET(type,
/* Obsoleted by RFC 973 */
DNS_TYPE_MD,
DNS_TYPE_MF,
DNS_TYPE_MAILA,
/* Kinda obsoleted by RFC 2505 */
DNS_TYPE_MB,
DNS_TYPE_MG,
DNS_TYPE_MR,
DNS_TYPE_MINFO,
DNS_TYPE_MAILB,
/* RFC1127 kinda obsoleted this by recommending against its use */
DNS_TYPE_WKS,
/* Declared historical by RFC 6563 */
DNS_TYPE_A6,
/* Obsoleted by DNSSEC-bis */
DNS_TYPE_NXT,
/* RFC 1035 removed support for concepts that needed this from RFC 883 */
DNS_TYPE_NULL);
}
bool dns_type_needs_authentication(uint16_t type) {
/* Returns true for all (non-obsolete) RR types where records are not useful if they aren't
* authenticated. I.e. everything that contains crypto keys. */
return IN_SET(type,
DNS_TYPE_CERT,
DNS_TYPE_SSHFP,
DNS_TYPE_IPSECKEY,
DNS_TYPE_DS,
DNS_TYPE_DNSKEY,
DNS_TYPE_TLSA,
DNS_TYPE_CDNSKEY,
DNS_TYPE_OPENPGPKEY,
DNS_TYPE_CAA);
}
int dns_type_to_af(uint16_t t) {
switch (t) {
case DNS_TYPE_A:
return AF_INET;
case DNS_TYPE_AAAA:
return AF_INET6;
case DNS_TYPE_ANY:
return AF_UNSPEC;
default:
return -EINVAL;
}
}
const char *dns_class_to_string(uint16_t class) {
switch (class) {
case DNS_CLASS_IN:
return "IN";
case DNS_CLASS_ANY:
return "ANY";
}
return NULL;
}
int dns_class_from_string(const char *s) {
if (!s)
return _DNS_CLASS_INVALID;
if (strcaseeq(s, "IN"))
return DNS_CLASS_IN;
else if (strcaseeq(s, "ANY"))
return DNS_CLASS_ANY;
return _DNS_CLASS_INVALID;
}
const char* tlsa_cert_usage_to_string(uint8_t cert_usage) {
switch (cert_usage) {
case 0:
return "CA constraint";
case 1:
return "Service certificate constraint";
case 2:
return "Trust anchor assertion";
case 3:
return "Domain-issued certificate";
case 4 ... 254:
return "Unassigned";
case 255:
return "Private use";
}
return NULL; /* clang cannot count that we covered everything */
}
const char* tlsa_selector_to_string(uint8_t selector) {
switch (selector) {
case 0:
return "Full Certificate";
case 1:
return "SubjectPublicKeyInfo";
case 2 ... 254:
return "Unassigned";
case 255:
return "Private use";
}
return NULL;
}
const char* tlsa_matching_type_to_string(uint8_t selector) {
switch (selector) {
case 0:
return "No hash used";
case 1:
return "SHA-256";
case 2:
return "SHA-512";
case 3 ... 254:
return "Unassigned";
case 255:
return "Private use";
}
return NULL;
}