/*
* Copyright (c) 2013-2015 Pablo Neira Ayuso <pablo@netfilter.org>
* Copyright (c) 2015 Arturo Borrero Gonzalez <arturo@debian.org>
*
* This program is free software; you can redistribute it and/or modifyi
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <stdlib.h>
#include <time.h>
#include <string.h>
#include <net/if.h>
#include <getopt.h>
#include <ctype.h> /* for isspace */
#include <statement.h>
#include <netlink.h>
#include <xt.h>
#include <erec.h>
#include <libmnl/libmnl.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables_compat.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter_arp/arp_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#ifdef HAVE_LIBXTABLES
#include <xtables.h>
#endif
void xt_stmt_xlate(const struct stmt *stmt, struct output_ctx *octx)
{
#ifdef HAVE_LIBXTABLES
struct xt_xlate *xl = xt_xlate_alloc(10240);
switch (stmt->xt.type) {
case NFT_XT_MATCH:
if (stmt->xt.match->xlate) {
struct xt_xlate_mt_params params = {
.ip = stmt->xt.entry,
.match = stmt->xt.match->m,
.numeric = 0,
};
stmt->xt.match->xlate(xl, ¶ms);
nft_print(octx, "%s", xt_xlate_get(xl));
} else if (stmt->xt.match->print) {
printf("#");
stmt->xt.match->print(&stmt->xt.entry,
stmt->xt.match->m, 0);
}
break;
case NFT_XT_WATCHER:
case NFT_XT_TARGET:
if (stmt->xt.target->xlate) {
struct xt_xlate_tg_params params = {
.ip = stmt->xt.entry,
.target = stmt->xt.target->t,
.numeric = 0,
};
stmt->xt.target->xlate(xl, ¶ms);
nft_print(octx, "%s", xt_xlate_get(xl));
} else if (stmt->xt.target->print) {
printf("#");
stmt->xt.target->print(NULL, stmt->xt.target->t, 0);
}
break;
default:
break;
}
xt_xlate_free(xl);
#else
nft_print(octx, "# xt_%s", stmt->xt.name);
#endif
}
void xt_stmt_destroy(struct stmt *stmt)
{
#ifdef HAVE_LIBXTABLES
switch (stmt->xt.type) {
case NFT_XT_MATCH:
if (!stmt->xt.match)
break;
if (stmt->xt.match->m)
xfree(stmt->xt.match->m);
xfree(stmt->xt.match);
break;
case NFT_XT_WATCHER:
case NFT_XT_TARGET:
if (!stmt->xt.target)
break;
if (stmt->xt.target->t)
xfree(stmt->xt.target->t);
xfree(stmt->xt.target);
break;
default:
break;
}
#endif
xfree(stmt->xt.entry);
xfree(stmt->xt.name);
}
#ifdef HAVE_LIBXTABLES
static void *xt_entry_alloc(struct xt_stmt *xt, uint32_t af)
{
union nft_entry {
struct ipt_entry ipt;
struct ip6t_entry ip6t;
struct arpt_entry arpt;
struct ebt_entry ebt;
} *entry;
entry = xmalloc(sizeof(union nft_entry));
switch (af) {
case NFPROTO_IPV4:
entry->ipt.ip.proto = xt->proto;
break;
case NFPROTO_IPV6:
entry->ip6t.ipv6.proto = xt->proto;
break;
case NFPROTO_BRIDGE:
entry->ebt.ethproto = xt->proto;
break;
case NFPROTO_ARP:
entry->arpt.arp.arhln_mask = 0xff;
entry->arpt.arp.arhln = 6;
break;
default:
break;
}
return entry;
}
static uint32_t xt_proto(const struct proto_ctx *pctx)
{
const struct proto_desc *desc = NULL;
if (pctx->family == NFPROTO_BRIDGE) {
desc = pctx->protocol[PROTO_BASE_NETWORK_HDR].desc;
if (desc == NULL)
return 0;
if (strcmp(desc->name, "ip") == 0)
return __constant_htons(ETH_P_IP);
if (strcmp(desc->name, "ip6") == 0)
return __constant_htons(ETH_P_IPV6);
return 0;
}
desc = pctx->protocol[PROTO_BASE_TRANSPORT_HDR].desc;
if (desc == NULL)
return 0;
if (strcmp(desc->name, "tcp") == 0)
return IPPROTO_TCP;
else if (strcmp(desc->name, "udp") == 0)
return IPPROTO_UDP;
else if (strcmp(desc->name, "udplite") == 0)
return IPPROTO_UDPLITE;
else if (strcmp(desc->name, "sctp") == 0)
return IPPROTO_SCTP;
else if (strcmp(desc->name, "dccp") == 0)
return IPPROTO_DCCP;
else if (strcmp(desc->name, "esp") == 0)
return IPPROTO_ESP;
else if (strcmp(desc->name, "ah") == 0)
return IPPROTO_AH;
return 0;
}
static struct xtables_target *xt_target_clone(struct xtables_target *t)
{
struct xtables_target *clone;
clone = xzalloc(sizeof(struct xtables_target));
memcpy(clone, t, sizeof(struct xtables_target));
return clone;
}
static struct xtables_match *xt_match_clone(struct xtables_match *m)
{
struct xtables_match *clone;
clone = xzalloc(sizeof(struct xtables_match));
memcpy(clone, m, sizeof(struct xtables_match));
return clone;
}
#endif
/*
* Delinearization
*/
void netlink_parse_match(struct netlink_parse_ctx *ctx,
const struct location *loc,
const struct nftnl_expr *nle)
{
struct stmt *stmt;
const char *name;
#ifdef HAVE_LIBXTABLES
struct xtables_match *mt;
const char *mtinfo;
struct xt_entry_match *m;
uint32_t mt_len;
xtables_set_nfproto(ctx->table->handle.family);
name = nftnl_expr_get_str(nle, NFTNL_EXPR_MT_NAME);
mt = xtables_find_match(name, XTF_TRY_LOAD, NULL);
if (!mt) {
fprintf(stderr, "XT match %s not found\n", name);
return;
}
mtinfo = nftnl_expr_get(nle, NFTNL_EXPR_MT_INFO, &mt_len);
m = xzalloc(sizeof(struct xt_entry_match) + mt_len);
memcpy(&m->data, mtinfo, mt_len);
m->u.match_size = mt_len + XT_ALIGN(sizeof(struct xt_entry_match));
m->u.user.revision = nftnl_expr_get_u32(nle, NFTNL_EXPR_MT_REV);
stmt = xt_stmt_alloc(loc);
stmt->xt.name = strdup(name);
stmt->xt.type = NFT_XT_MATCH;
stmt->xt.match = xt_match_clone(mt);
stmt->xt.match->m = m;
#else
name = nftnl_expr_get_str(nle, NFTNL_EXPR_MT_NAME);
stmt = xt_stmt_alloc(loc);
stmt->xt.name = strdup(name);
stmt->xt.type = NFT_XT_MATCH;
#endif
list_add_tail(&stmt->list, &ctx->rule->stmts);
}
void netlink_parse_target(struct netlink_parse_ctx *ctx,
const struct location *loc,
const struct nftnl_expr *nle)
{
struct stmt *stmt;
const char *name;
#ifdef HAVE_LIBXTABLES
struct xtables_target *tg;
const void *tginfo;
struct xt_entry_target *t;
size_t size;
uint32_t tg_len;
xtables_set_nfproto(ctx->table->handle.family);
name = nftnl_expr_get_str(nle, NFTNL_EXPR_TG_NAME);
tg = xtables_find_target(name, XTF_TRY_LOAD);
if (!tg) {
fprintf(stderr, "XT target %s not found\n", name);
return;
}
tginfo = nftnl_expr_get(nle, NFTNL_EXPR_TG_INFO, &tg_len);
size = XT_ALIGN(sizeof(struct xt_entry_target)) + tg_len;
t = xzalloc(size);
memcpy(&t->data, tginfo, tg_len);
t->u.target_size = size;
t->u.user.revision = nftnl_expr_get_u32(nle, NFTNL_EXPR_TG_REV);
strcpy(t->u.user.name, tg->name);
stmt = xt_stmt_alloc(loc);
stmt->xt.name = strdup(name);
stmt->xt.type = NFT_XT_TARGET;
stmt->xt.target = xt_target_clone(tg);
stmt->xt.target->t = t;
#else
name = nftnl_expr_get_str(nle, NFTNL_EXPR_TG_NAME);
stmt = xt_stmt_alloc(loc);
stmt->xt.name = strdup(name);
stmt->xt.type = NFT_XT_TARGET;
#endif
list_add_tail(&stmt->list, &ctx->rule->stmts);
}
#ifdef HAVE_LIBXTABLES
static bool is_watcher(uint32_t family, struct stmt *stmt)
{
if (family != NFPROTO_BRIDGE ||
stmt->xt.type != NFT_XT_TARGET)
return false;
/* this has to be hardcoded :-( */
if (strcmp(stmt->xt.name, "log") == 0)
return true;
else if (strcmp(stmt->xt.name, "nflog") == 0)
return true;
return false;
}
void stmt_xt_postprocess(struct rule_pp_ctx *rctx, struct stmt *stmt,
struct rule *rule)
{
if (is_watcher(rctx->pctx.family, stmt))
stmt->xt.type = NFT_XT_WATCHER;
stmt->xt.proto = xt_proto(&rctx->pctx);
stmt->xt.entry = xt_entry_alloc(&stmt->xt, rctx->pctx.family);
}
static int nft_xt_compatible_revision(const char *name, uint8_t rev, int opt)
{
struct mnl_socket *nl;
char buf[MNL_SOCKET_BUFFER_SIZE];
struct nlmsghdr *nlh;
uint32_t portid, seq, type, family;
struct nfgenmsg *nfg;
int ret = 0;
switch (rev) {
case IPT_SO_GET_REVISION_MATCH:
family = NFPROTO_IPV4;
type = 0;
break;
case IPT_SO_GET_REVISION_TARGET:
family = NFPROTO_IPV4;
type = 1;
break;
case IP6T_SO_GET_REVISION_MATCH:
family = NFPROTO_IPV6;
type = 0;
break;
case IP6T_SO_GET_REVISION_TARGET:
family = NFPROTO_IPV6;
type = 1;
break;
default: /* No revision support, assume ok */
return 1;
}
nlh = mnl_nlmsg_put_header(buf);
nlh->nlmsg_type = (NFNL_SUBSYS_NFT_COMPAT << 8) | NFNL_MSG_COMPAT_GET;
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
nlh->nlmsg_seq = seq = time(NULL);
nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
nfg->nfgen_family = family;
nfg->version = NFNETLINK_V0;
nfg->res_id = 0;
mnl_attr_put_strz(nlh, NFTA_COMPAT_NAME, name);
mnl_attr_put_u32(nlh, NFTA_COMPAT_REV, htonl(rev));
mnl_attr_put_u32(nlh, NFTA_COMPAT_TYPE, htonl(type));
nl = mnl_socket_open(NETLINK_NETFILTER);
if (nl == NULL)
return 0;
if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0)
goto err;
portid = mnl_socket_get_portid(nl);
if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0)
goto err;
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
if (ret == -1)
goto err;
ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL);
if (ret == -1)
goto err;
err:
mnl_socket_close(nl);
return ret < 0 ? 0 : 1;
}
static struct option original_opts[] = {
{ NULL },
};
static struct xtables_globals xt_nft_globals = {
.program_name = "nft",
.program_version = PACKAGE_VERSION,
.orig_opts = original_opts,
.compat_rev = nft_xt_compatible_revision,
};
void xt_init(void)
{
/* Default to IPv4, but this changes in runtime */
xtables_init_all(&xt_nft_globals, NFPROTO_IPV4);
}
#endif