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Release 4.8 net/netfilter/nf_nat_sip.c

Directory: net/netfilter
/* 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; }

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patrick mchardypatrick mchardy207100.00%5100.00%
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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); } }

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patrick mchardypatrick mchardy81100.00%1100.00%
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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); }

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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); }

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patrick mchardypatrick mchardy30894.48%872.73%
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herbert xuherbert xu20.61%19.09%
harvey harrisonharvey harrison10.31%19.09%
Total326100.00%11100.00%


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); }

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patrick mchardypatrick mchardy123100.00%5100.00%
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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; }

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patrick mchardypatrick mchardy87981.16%1470.00%
pablo neira ayusopablo neira ayuso978.96%15.00%
kevin cernekeekevin cernekee888.13%15.00%
harvey harrisonharvey harrison121.11%15.00%
herbert xuherbert xu40.37%15.00%
balazs peter odorbalazs peter odor20.18%15.00%
rasmus villemoesrasmus villemoes10.09%15.00%
Total1083100.00%20100.00%


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); }

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patrick mchardypatrick mchardy83100.00%3100.00%
Total83100.00%3100.00%

/* 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); } }

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patrick mchardypatrick mchardy157100.00%4100.00%
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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; }

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pablo neira ayusopablo neira ayuso469.35%220.00%
kevin cernekeekevin cernekee346.91%110.00%
eric dumazeteric dumazet10.20%110.00%
harvey harrisonharvey harrison10.20%110.00%
Total492100.00%10100.00%


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); }

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herbert xuherbert xu21.16%112.50%
Total172100.00%8100.00%


static int mangle_sdp_packet(struct sk_buff *skb, unsigned int protoff, unsigned int dataoff, const