// SPDX-License-Identifier: GPL-2.0-only
/* SIP extension for NAT alteration.
*
* (C) 2005 by Christian Hentschel <[email protected]>
* based on RR's ip_nat_ftp.c and other modules.
* (C) 2007 United Security Providers
* (C) 2007, 2008, 2011, 2012 Patrick McHardy <[email protected]>
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/inet.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_helper.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_seqadj.h>
#include <linux/netfilter/nf_conntrack_sip.h>
#define NAT_HELPER_NAME "sip"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Hentschel <[email protected]>");
MODULE_DESCRIPTION("SIP NAT helper");
MODULE_ALIAS_NF_NAT_HELPER(NAT_HELPER_NAME);
static struct nf_conntrack_nat_helper nat_helper_sip =
NF_CT_NAT_HELPER_INIT(NAT_HELPER_NAME);
static unsigned int mangle_packet(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
unsigned int matchoff, unsigned int matchlen,
const char *buffer, unsigned int buflen)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
struct tcphdr *th;
unsigned int baseoff;
if (nf_ct_protonum(ct) == IPPROTO_TCP) {
th = (struct tcphdr *)(skb->data + protoff);
baseoff = protoff + th->doff * 4;
matchoff += dataoff - baseoff;
if (!__nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
protoff, matchoff, matchlen,
buffer, buflen, false))
return 0;
} else {
baseoff = protoff + sizeof(struct udphdr);
matchoff += dataoff - baseoff;
if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo,
protoff, matchoff, matchlen,
buffer, buflen))
return 0;
}
/* Reload data pointer and adjust datalen value */
*dptr = skb->data + dataoff;
*datalen += buflen - matchlen;
return 1;
}
static int sip_sprintf_addr(const struct nf_conn *ct, char *buffer,
const union nf_inet_addr *addr, bool delim)
{
if (nf_ct_l3num(ct) == NFPROTO_IPV4)
return sprintf(buffer, "%pI4", &addr->ip);
else {
if (delim)
return sprintf(buffer, "[%pI6c]", &addr->ip6);
else
return sprintf(buffer, "%pI6c", &addr->ip6);
}
}
static int sip_sprintf_addr_port(const struct nf_conn *ct, char *buffer,
const union nf_inet_addr *addr, u16 port)
{
if (nf_ct_l3num(ct) == NFPROTO_IPV4)
return sprintf(buffer, "%pI4:%u", &addr->ip, port);
else
return sprintf(buffer, "[%pI6c]:%u", &addr->ip6, port);
}
static int map_addr(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
unsigned int matchoff, unsigned int matchlen,
union nf_inet_addr *addr, __be16 port)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")];
unsigned int buflen;
union nf_inet_addr newaddr;
__be16 newport;
if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, addr) &&
ct->tuplehash[dir].tuple.src.u.udp.port == port) {
newaddr = ct->tuplehash[!dir].tuple.dst.u3;
newport = ct->tuplehash[!dir].tuple.dst.u.udp.port;
} else if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, addr) &&
ct->tuplehash[dir].tuple.dst.u.udp.port == port) {
newaddr = ct->tuplehash[!dir].tuple.src.u3;
newport = ct_sip_info->forced_dport ? :
ct->tuplehash[!dir].tuple.src.u.udp.port;
} else
return 1;
if (nf_inet_addr_cmp(&newaddr, addr) && newport == port)
return 1;
buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, ntohs(newport));
return mangle_packet(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen, buffer, buflen);
}
static int map_sip_addr(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
enum sip_header_types type)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
unsigned int matchlen, matchoff;
union nf_inet_addr addr;
__be16 port;
if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, type, NULL,
&matchoff, &matchlen, &addr, &port) <= 0)
return 1;
return map_addr(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen, &addr, port);
}
static unsigned int nf_nat_sip(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
unsigned int coff, matchoff, matchlen;
enum sip_header_types hdr;
union nf_inet_addr addr;
__be16 port;
int request, in_header;
/* Basic rules: requests and responses. */
if (strncasecmp(*dptr, "SIP/2.0", strlen("SIP/2.0")) != 0) {
if (ct_sip_parse_request(ct, *dptr, *datalen,
&matchoff, &matchlen,
&addr, &port) > 0 &&
!map_addr(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen, &addr, port)) {
nf_ct_helper_log(skb, ct, "cannot mangle SIP message");
return NF_DROP;
}
request = 1;
} else
request = 0;
if (nf_ct_protonum(ct) == IPPROTO_TCP)
hdr = SIP_HDR_VIA_TCP;
else
hdr = SIP_HDR_VIA_UDP;
/* Translate topmost Via header and parameters */
if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen,
hdr, NULL, &matchoff, &matchlen,
&addr, &port) > 0) {
unsigned int olen, matchend, poff, plen, buflen, n;
char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")];
/* We're only interested in headers related to this
* connection */
if (request) {
if (!nf_inet_addr_cmp(&addr,
&ct->tuplehash[dir].tuple.src.u3) ||
port != ct->tuplehash[dir].tuple.src.u.udp.port)
goto next;
} else {
if (!nf_inet_addr_cmp(&addr,
&ct->tuplehash[dir].tuple.dst.u3) ||
port != ct->tuplehash[dir].tuple.dst.u.udp.port)
goto next;
}
olen = *datalen;
if (!map_addr(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen, &addr, port)) {
nf_ct_helper_log(skb, ct, "cannot mangle Via header");
return NF_DROP;
}
matchend = matchoff + matchlen + *datalen - olen;
/* The maddr= parameter (RFC 2361) specifies where to send
* the reply. */
if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen,
"maddr=", &poff, &plen,
&addr, true) > 0 &&
nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.src.u3) &&
!nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.dst.u3)) {
buflen = sip_sprintf_addr(ct, buffer,
&ct->tuplehash[!dir].tuple.dst.u3,
true);
if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
poff, plen, buffer, buflen)) {
nf_ct_helper_log(skb, ct, "cannot mangle maddr");
return NF_DROP;
}
}
/* The received= parameter (RFC 2361) contains the address
* from which the server received the request. */
if (ct_sip_parse_address_param(ct, *dptr, matchend, *datalen,
"received=", &poff, &plen,
&addr, false) > 0 &&
nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.dst.u3) &&
!nf_inet_addr_cmp(&addr, &ct->tuplehash[!dir].tuple.src.u3)) {
buflen = sip_sprintf_addr(ct, buffer,
&ct->tuplehash[!dir].tuple.src.u3,
false);
if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
poff, plen, buffer, buflen)) {
nf_ct_helper_log(skb, ct, "cannot mangle received");
return NF_DROP;
}
}
/* The rport= parameter (RFC 3581) contains the port number
* from which the server received the request. */
if (ct_sip_parse_numerical_param(ct, *dptr, matchend, *datalen,
"rport=", &poff, &plen,
&n) > 0 &&
htons(n) == ct->tuplehash[dir].tuple.dst.u.udp.port &&
htons(n) != ct->tuplehash[!dir].tuple.src.u.udp.port) {
__be16 p = ct->tuplehash[!dir].tuple.src.u.udp.port;
buflen = sprintf(buffer, "%u", ntohs(p));
if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
poff, plen, buffer, buflen)) {
nf_ct_helper_log(skb, ct, "cannot mangle rport");
return NF_DROP;
}
}
}
next:
/* Translate Contact headers */
coff = 0;
in_header = 0;
while (ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen,
SIP_HDR_CONTACT, &in_header,
&matchoff, &matchlen,
&addr, &port) > 0) {
if (!map_addr(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen,
&addr, port)) {
nf_ct_helper_log(skb, ct, "cannot mangle contact");
return NF_DROP;
}
}
if (!map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_FROM) ||
!map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_TO)) {
nf_ct_helper_log(skb, ct, "cannot mangle SIP from/to");
return NF_DROP;
}
/* Mangle destination port for Cisco phones, then fix up checksums */
if (dir == IP_CT_DIR_REPLY && ct_sip_info->forced_dport) {
struct udphdr *uh;
if (skb_ensure_writable(skb, skb->len)) {
nf_ct_helper_log(skb, ct, "cannot mangle packet");
return NF_DROP;
}
uh = (void *)skb->data + protoff;
uh->dest = ct_sip_info->forced_dport;
if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff,
0, 0, NULL, 0)) {
nf_ct_helper_log(skb, ct, "cannot mangle packet");
return NF_DROP;
}
}
return NF_ACCEPT;
}
static void nf_nat_sip_seq_adjust(struct sk_buff *skb, unsigned int protoff,
s16 off)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
const struct tcphdr *th;
if (nf_ct_protonum(ct) != IPPROTO_TCP || off == 0)
return;
th = (struct tcphdr *)(skb->data + protoff);
nf_ct_seqadj_set(ct, ctinfo, th->seq, off);
}
/* Handles expected signalling connections and media streams */
static void nf_nat_sip_expected(struct nf_conn *ct,
struct nf_conntrack_expect *exp)
{
struct nf_conn_help *help = nfct_help(ct->master);
struct nf_conntrack_expect *pair_exp;
int range_set_for_snat = 0;
struct nf_nat_range2 range;
/* This must be a fresh one. */
BUG_ON(ct->status & IPS_NAT_DONE_MASK);
/* For DST manip, map port here to where it's expected. */
range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED);
range.min_proto = range.max_proto = exp->saved_proto;
range.min_addr = range.max_addr = exp->saved_addr;
nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
/* Do media streams SRC manip according with the parameters
* found in the paired expectation.
*/
if (exp->class != SIP_EXPECT_SIGNALLING) {
spin_lock_bh(&nf_conntrack_expect_lock);
hlist_for_each_entry(pair_exp, &help->expectations, lnode) {
if (pair_exp->tuple.src.l3num == nf_ct_l3num(ct) &&
pair_exp->tuple.dst.protonum == ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum &&
nf_inet_addr_cmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3, &pair_exp->saved_addr) &&
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all == pair_exp->saved_proto.all) {
range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED);
range.min_proto.all = range.max_proto.all = pair_exp->tuple.dst.u.all;
range.min_addr = range.max_addr = pair_exp->tuple.dst.u3;
range_set_for_snat = 1;
break;
}
}
spin_unlock_bh(&nf_conntrack_expect_lock);
}
/* When no paired expectation has been found, change src to
* where master sends to, but only if the connection actually came
* from the same source.
*/
if (!range_set_for_snat &&
nf_inet_addr_cmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
&ct->master->tuplehash[exp->dir].tuple.src.u3)) {
range.flags = NF_NAT_RANGE_MAP_IPS;
range.min_addr = range.max_addr
= ct->master->tuplehash[!exp->dir].tuple.dst.u3;
range_set_for_snat = 1;
}
/* Perform SRC manip. */
if (range_set_for_snat)
nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
}
static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
struct nf_conntrack_expect *exp,
unsigned int matchoff,
unsigned int matchlen)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
union nf_inet_addr newaddr;
u_int16_t port;
__be16 srcport;
char buffer[INET6_ADDRSTRLEN + sizeof("[]:nnnnn")];
unsigned int buflen;
/* Connection will come from reply */
if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
&ct->tuplehash[!dir].tuple.dst.u3))
newaddr = exp->tuple.dst.u3;
else
newaddr = ct->tuplehash[!dir].tuple.dst.u3;
/* If the signalling port matches the connection's source port in the
* original direction, try to use the destination port in the opposite
* direction. */
srcport = ct_sip_info->forced_dport ? :
ct->tuplehash[dir].tuple.src.u.udp.port;
if (exp->tuple.dst.u.udp.port == srcport)
port = ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port);
else
port = ntohs(exp->tuple.dst.u.udp.port);
exp->saved_addr = exp->tuple.dst.u3;
exp->tuple.dst.u3 = newaddr;
exp->saved_proto.udp.port = exp->tuple.dst.u.udp.port;
exp->dir = !dir;
exp->expectfn = nf_nat_sip_expected;
port = nf_nat_exp_find_port(exp, port);
if (port == 0) {
nf_ct_helper_log(skb, ct, "all ports in use for SIP");
return NF_DROP;
}
if (!nf_inet_addr_cmp(&exp->tuple.dst.u3, &exp->saved_addr) ||
exp->tuple.dst.u.udp.port != exp->saved_proto.udp.port) {
buflen = sip_sprintf_addr_port(ct, buffer, &newaddr, port);
if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen, buffer, buflen)) {
nf_ct_helper_log(skb, ct, "cannot mangle packet");
goto err;
}
}
return NF_ACCEPT;
err:
nf_ct_unexpect_related(exp);
return NF_DROP;
}
static int mangle_content_len(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
unsigned int matchoff, matchlen;
char buffer[sizeof("65536")];
int buflen, c_len;
/* Get actual SDP length */
if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen,
SDP_HDR_VERSION, SDP_HDR_UNSPEC,
&matchoff, &matchlen) <= 0)
return 0;
c_len = *datalen - matchoff + strlen("v=");
/* Now, update SDP length */
if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_CONTENT_LENGTH,
&matchoff, &matchlen) <= 0)
return 0;
buflen = sprintf(buffer, "%u", c_len);
return mangle_packet(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen, buffer, buflen);
}
static int mangle_sdp_packet(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
unsigned int sdpoff,
enum sdp_header_types type,
enum sdp_header_types term,
char *buffer, int buflen)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
unsigned int matchlen, matchoff;
if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, type, term,
&matchoff, &matchlen) <= 0)
return -ENOENT;
return mangle_packet(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen, buffer, buflen) ? 0 : -EINVAL;
}
static unsigned int nf_nat_sdp_addr(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
unsigned int sdpoff,
enum sdp_header_types type,
enum sdp_header_types term,
const union nf_inet_addr *addr)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
char buffer[INET6_ADDRSTRLEN];
unsigned int buflen;
buflen = sip_sprintf_addr(ct, buffer, addr, false);
if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen,
sdpoff, type, term, buffer, buflen))
return 0;
return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
}
static unsigned int nf_nat_sdp_port(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
unsigned int matchoff,
unsigned int matchlen,
u_int16_t port)
{
char buffer[sizeof("nnnnn")];
unsigned int buflen;
buflen = sprintf(buffer, "%u", port);
if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
matchoff, matchlen, buffer, buflen))
return 0;
return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
}
static unsigned int nf_nat_sdp_session(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
unsigned int sdpoff,
const union nf_inet_addr *addr)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
char buffer[INET6_ADDRSTRLEN];
unsigned int buflen;
/* Mangle session description owner and contact addresses */
buflen = sip_sprintf_addr(ct, buffer, addr, false);
if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff,
SDP_HDR_OWNER, SDP_HDR_MEDIA, buffer, buflen))
return 0;
switch (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff,
SDP_HDR_CONNECTION, SDP_HDR_MEDIA,
buffer, buflen)) {
case 0:
/*
* RFC 2327:
*
* Session description
*
* c=* (connection information - not required if included in all media)
*/
case -ENOENT:
break;
default:
return 0;
}
return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
}
/* So, this packet has hit the connection tracking matching code.
Mangle it, and change the expectation to match the new version. */
static unsigned int nf_nat_sdp_media(struct sk_buff *skb, unsigned int protoff,
unsigned int dataoff,
const char **dptr, unsigned int *datalen,
struct nf_conntrack_expect *rtp_exp,
struct nf_conntrack_expect *rtcp_exp,
unsigned int mediaoff,
unsigned int medialen,
union nf_inet_addr *rtp_addr)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
u_int16_t port;
/* Connection will come from reply */
if (nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
&ct->tuplehash[!dir].tuple.dst.u3))
*rtp_addr = rtp_exp->tuple.dst.u3;
else
*rtp_addr = ct->tuplehash[!dir].tuple.dst.u3;
rtp_exp->saved_addr = rtp_exp->tuple.dst.u3;
rtp_exp->tuple.dst.u3 = *rtp_addr;
rtp_exp->saved_proto.udp.port = rtp_exp->tuple.dst.u.udp.port;
rtp_exp->dir = !dir;
rtp_exp->expectfn = nf_nat_sip_expected;
rtcp_exp->saved_addr = rtcp_exp->tuple.dst.u3;
rtcp_exp->tuple.dst.u3 = *rtp_addr;
rtcp_exp->saved_proto.udp.port = rtcp_exp->tuple.dst.u.udp.port;
rtcp_exp->dir = !dir;
rtcp_exp->expectfn = nf_nat_sip_expected;
/* Try to get same pair of ports: if not, try to change them. */
for (port = ntohs(rtp_exp->tuple.dst.u.udp.port);
port != 0; port += 2) {
int ret;
rtp_exp->tuple.dst.u.udp.port = htons(port);
ret = nf_ct_expect_related(rtp_exp,
NF_CT_EXP_F_SKIP_MASTER);
if (ret == -EBUSY)
continue;
else if (ret < 0) {
port = 0;
break;
}
rtcp_exp->tuple.dst.u.udp.port = htons(port + 1);
ret = nf_ct_expect_related(rtcp_exp,
NF_CT_EXP_F_SKIP_MASTER);
if (ret == 0)
break;
else if (ret == -EBUSY) {
nf_ct_unexpect_related(rtp_exp);
continue;
} else if (ret < 0) {
nf_ct_unexpect_related(rtp_exp);
port = 0;
break;
}
}
if (port == 0) {
nf_ct_helper_log(skb, ct, "all ports in use for SDP media");
goto err1;
}
/* Update media port. */
if (rtp_exp->tuple.dst.u.udp.port != rtp_exp->saved_proto.udp.port &&
!nf_nat_sdp_port(skb, protoff, dataoff, dptr, datalen,
mediaoff, medialen, port)) {
nf_ct_helper_log(skb, ct, "cannot mangle SDP message");
goto err2;
}
return NF_ACCEPT;
err2:
nf_ct_unexpect_related(rtp_exp);
nf_ct_unexpect_related(rtcp_exp);
err1:
return NF_DROP;
}
static struct nf_ct_helper_expectfn sip_nat = {
.name = "sip",
.expectfn = nf_nat_sip_expected,
};
static void __exit nf_nat_sip_fini(void)
{
nf_nat_helper_unregister(&nat_helper_sip);
RCU_INIT_POINTER(nf_nat_sip_hooks, NULL);
nf_ct_helper_expectfn_unregister(&sip_nat);
synchronize_rcu();
}
static const struct nf_nat_sip_hooks sip_hooks = {
.msg = nf_nat_sip,
.seq_adjust = nf_nat_sip_seq_adjust,
.expect = nf_nat_sip_expect,
.sdp_addr = nf_nat_sdp_addr,
.sdp_port = nf_nat_sdp_port,
.sdp_session = nf_nat_sdp_session,
.sdp_media = nf_nat_sdp_media,
};
static int __init nf_nat_sip_init(void)
{
BUG_ON(nf_nat_sip_hooks != NULL);
nf_nat_helper_register(&nat_helper_sip);
RCU_INIT_POINTER(nf_nat_sip_hooks, &sip_hooks);
nf_ct_helper_expectfn_register(&sip_nat);
return 0;
}
module_init(nf_nat_sip_init);
module_exit(nf_nat_sip_fini);
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