Release 4.11 net/netfilter/nf_nat_sip.c
/* SIP extension for NAT alteration.
*
* (C) 2005 by Christian Hentschel <chentschel@arnet.com.ar>
* based on RR's ip_nat_ftp.c and other modules.
* (C) 2007 United Security Providers
* (C) 2007, 2008, 2011, 2012 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#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_helper.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_seqadj.h>
#include <linux/netfilter/nf_conntrack_sip.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>");
MODULE_DESCRIPTION("SIP NAT helper");
MODULE_ALIAS("ip_nat_sip");
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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 207 | 100.00% | 5 | 100.00% |
Total | 207 | 100.00% | 5 | 100.00% |
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);
}
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 81 | 100.00% | 1 | 100.00% |
Total | 81 | 100.00% | 1 | 100.00% |
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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 65 | 100.00% | 1 | 100.00% |
Total | 65 | 100.00% | 1 | 100.00% |
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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 308 | 94.48% | 8 | 72.73% |
Kevin Cernekee | 15 | 4.60% | 1 | 9.09% |
Herbert Xu | 2 | 0.61% | 1 | 9.09% |
Harvey Harrison | 1 | 0.31% | 1 | 9.09% |
Total | 326 | 100.00% | 11 | 100.00% |
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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 123 | 100.00% | 5 | 100.00% |
Total | 123 | 100.00% | 5 | 100.00% |
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_make_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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 879 | 81.16% | 14 | 70.00% |
Pablo Neira Ayuso | 97 | 8.96% | 1 | 5.00% |
Kevin Cernekee | 88 | 8.13% | 1 | 5.00% |
Harvey Harrison | 12 | 1.11% | 1 | 5.00% |
Herbert Xu | 4 | 0.37% | 1 | 5.00% |
Balazs Peter Odor | 2 | 0.18% | 1 | 5.00% |
Rasmus Villemoes | 1 | 0.09% | 1 | 5.00% |
Total | 1083 | 100.00% | 20 | 100.00% |
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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 83 | 100.00% | 3 | 100.00% |
Total | 83 | 100.00% | 3 | 100.00% |
/* Handles expected signalling connections and media streams */
static void nf_nat_sip_expected(struct nf_conn *ct,
struct nf_conntrack_expect *exp)
{
struct nf_nat_range 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);
/* Change src to where master sends to, but only if the connection
* actually came from the same source. */
if (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;
nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
}
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 157 | 100.00% | 4 | 100.00% |
Total | 157 | 100.00% | 4 | 100.00% |
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;
for (; port != 0; port++) {
int ret;
exp->tuple.dst.u.udp.port = htons(port);
ret = nf_ct_expect_related(exp);
if (ret == 0)
break;
else if (ret != -EBUSY) {
port = 0;
break;
}
}
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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 410 | 83.33% | 5 | 50.00% |
Pablo Neira Ayuso | 46 | 9.35% | 2 | 20.00% |
Kevin Cernekee | 34 | 6.91% | 1 | 10.00% |
Harvey Harrison | 1 | 0.20% | 1 | 10.00% |
Eric Dumazet | 1 | 0.20% | 1 | 10.00% |
Total | 492 | 100.00% | 10 | 100.00% |
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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Patrick McHardy | 170 | 98.84% | 7 | 87.50% |
Herbert Xu | 2 | 1.16% | 1 | 12.50% |
Total | 172 | 100.00% | 8 | 100.00% |
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,