diff options
Diffstat (limited to 'net/ipv4/netfilter/nf_nat_sip.c')
-rw-r--r-- | net/ipv4/netfilter/nf_nat_sip.c | 154 |
1 files changed, 98 insertions, 56 deletions
diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c index 07d61a5..11b538d 100644 --- a/net/ipv4/netfilter/nf_nat_sip.c +++ b/net/ipv4/netfilter/nf_nat_sip.c @@ -1,4 +1,4 @@ -/* SIP extension for UDP NAT alteration. +/* 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. @@ -15,6 +15,7 @@ #include <linux/ip.h> #include <net/ip.h> #include <linux/udp.h> +#include <linux/tcp.h> #include <net/netfilter/nf_nat.h> #include <net/netfilter/nf_nat_helper.h> @@ -29,25 +30,42 @@ MODULE_DESCRIPTION("SIP NAT helper"); MODULE_ALIAS("ip_nat_sip"); -static unsigned int mangle_packet(struct sk_buff *skb, +static unsigned int mangle_packet(struct sk_buff *skb, 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); - - if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, matchoff, matchlen, - buffer, buflen)) - return 0; + struct tcphdr *th; + unsigned int baseoff; + + if (nf_ct_protonum(ct) == IPPROTO_TCP) { + th = (struct tcphdr *)(skb->data + ip_hdrlen(skb)); + baseoff = ip_hdrlen(skb) + th->doff * 4; + matchoff += dataoff - baseoff; + + if (!__nf_nat_mangle_tcp_packet(skb, ct, ctinfo, + matchoff, matchlen, + buffer, buflen, false)) + return 0; + } else { + baseoff = ip_hdrlen(skb) + sizeof(struct udphdr); + matchoff += dataoff - baseoff; + + if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, + matchoff, matchlen, + buffer, buflen)) + return 0; + } /* Reload data pointer and adjust datalen value */ - *dptr = skb->data + ip_hdrlen(skb) + sizeof(struct udphdr); + *dptr = skb->data + dataoff; *datalen += buflen - matchlen; return 1; } -static int map_addr(struct sk_buff *skb, +static int map_addr(struct sk_buff *skb, unsigned int dataoff, const char **dptr, unsigned int *datalen, unsigned int matchoff, unsigned int matchlen, union nf_inet_addr *addr, __be16 port) @@ -76,11 +94,11 @@ static int map_addr(struct sk_buff *skb, buflen = sprintf(buffer, "%pI4:%u", &newaddr, ntohs(newport)); - return mangle_packet(skb, dptr, datalen, matchoff, matchlen, + return mangle_packet(skb, dataoff, dptr, datalen, matchoff, matchlen, buffer, buflen); } -static int map_sip_addr(struct sk_buff *skb, +static int map_sip_addr(struct sk_buff *skb, unsigned int dataoff, const char **dptr, unsigned int *datalen, enum sip_header_types type) { @@ -93,16 +111,18 @@ static int map_sip_addr(struct sk_buff *skb, if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, type, NULL, &matchoff, &matchlen, &addr, &port) <= 0) return 1; - return map_addr(skb, dptr, datalen, matchoff, matchlen, &addr, port); + return map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen, + &addr, port); } -static unsigned int ip_nat_sip(struct sk_buff *skb, +static unsigned int ip_nat_sip(struct sk_buff *skb, 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); - unsigned int dataoff, matchoff, matchlen; + unsigned int coff, matchoff, matchlen; + enum sip_header_types hdr; union nf_inet_addr addr; __be16 port; int request, in_header; @@ -112,16 +132,21 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, if (ct_sip_parse_request(ct, *dptr, *datalen, &matchoff, &matchlen, &addr, &port) > 0 && - !map_addr(skb, dptr, datalen, matchoff, matchlen, + !map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen, &addr, port)) 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, - SIP_HDR_VIA, NULL, &matchoff, &matchlen, + hdr, NULL, &matchoff, &matchlen, &addr, &port) > 0) { unsigned int matchend, poff, plen, buflen, n; char buffer[sizeof("nnn.nnn.nnn.nnn:nnnnn")]; @@ -138,7 +163,7 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, goto next; } - if (!map_addr(skb, dptr, datalen, matchoff, matchlen, + if (!map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen, &addr, port)) return NF_DROP; @@ -153,8 +178,8 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, addr.ip != ct->tuplehash[!dir].tuple.dst.u3.ip) { buflen = sprintf(buffer, "%pI4", &ct->tuplehash[!dir].tuple.dst.u3.ip); - if (!mangle_packet(skb, dptr, datalen, poff, plen, - buffer, buflen)) + if (!mangle_packet(skb, dataoff, dptr, datalen, + poff, plen, buffer, buflen)) return NF_DROP; } @@ -167,8 +192,8 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, addr.ip != ct->tuplehash[!dir].tuple.src.u3.ip) { buflen = sprintf(buffer, "%pI4", &ct->tuplehash[!dir].tuple.src.u3.ip); - if (!mangle_packet(skb, dptr, datalen, poff, plen, - buffer, buflen)) + if (!mangle_packet(skb, dataoff, dptr, datalen, + poff, plen, buffer, buflen)) return NF_DROP; } @@ -181,31 +206,45 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, 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, dptr, datalen, poff, plen, - buffer, buflen)) + if (!mangle_packet(skb, dataoff, dptr, datalen, + poff, plen, buffer, buflen)) return NF_DROP; } } next: /* Translate Contact headers */ - dataoff = 0; + coff = 0; in_header = 0; - while (ct_sip_parse_header_uri(ct, *dptr, &dataoff, *datalen, + while (ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen, SIP_HDR_CONTACT, &in_header, &matchoff, &matchlen, &addr, &port) > 0) { - if (!map_addr(skb, dptr, datalen, matchoff, matchlen, + if (!map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen, &addr, port)) return NF_DROP; } - if (!map_sip_addr(skb, dptr, datalen, SIP_HDR_FROM) || - !map_sip_addr(skb, dptr, datalen, SIP_HDR_TO)) + if (!map_sip_addr(skb, dataoff, dptr, datalen, SIP_HDR_FROM) || + !map_sip_addr(skb, dataoff, dptr, datalen, SIP_HDR_TO)) return NF_DROP; + return NF_ACCEPT; } +static void ip_nat_sip_seq_adjust(struct sk_buff *skb, 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 + ip_hdrlen(skb)); + nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off); +} + /* Handles expected signalling connections and media streams */ static void ip_nat_sip_expected(struct nf_conn *ct, struct nf_conntrack_expect *exp) @@ -232,7 +271,7 @@ static void ip_nat_sip_expected(struct nf_conn *ct, } } -static unsigned int ip_nat_sip_expect(struct sk_buff *skb, +static unsigned int ip_nat_sip_expect(struct sk_buff *skb, unsigned int dataoff, const char **dptr, unsigned int *datalen, struct nf_conntrack_expect *exp, unsigned int matchoff, @@ -279,8 +318,8 @@ static unsigned int ip_nat_sip_expect(struct sk_buff *skb, if (exp->tuple.dst.u3.ip != exp->saved_ip || exp->tuple.dst.u.udp.port != exp->saved_proto.udp.port) { buflen = sprintf(buffer, "%pI4:%u", &newip, port); - if (!mangle_packet(skb, dptr, datalen, matchoff, matchlen, - buffer, buflen)) + if (!mangle_packet(skb, dataoff, dptr, datalen, + matchoff, matchlen, buffer, buflen)) goto err; } return NF_ACCEPT; @@ -290,7 +329,7 @@ err: return NF_DROP; } -static int mangle_content_len(struct sk_buff *skb, +static int mangle_content_len(struct sk_buff *skb, unsigned int dataoff, const char **dptr, unsigned int *datalen) { enum ip_conntrack_info ctinfo; @@ -312,12 +351,13 @@ static int mangle_content_len(struct sk_buff *skb, return 0; buflen = sprintf(buffer, "%u", c_len); - return mangle_packet(skb, dptr, datalen, matchoff, matchlen, + return mangle_packet(skb, dataoff, dptr, datalen, matchoff, matchlen, buffer, buflen); } -static int mangle_sdp_packet(struct sk_buff *skb, const char **dptr, - unsigned int dataoff, unsigned int *datalen, +static int mangle_sdp_packet(struct sk_buff *skb, 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) @@ -326,16 +366,16 @@ static int mangle_sdp_packet(struct sk_buff *skb, const char **dptr, struct nf_conn *ct = nf_ct_get(skb, &ctinfo); unsigned int matchlen, matchoff; - if (ct_sip_get_sdp_header(ct, *dptr, dataoff, *datalen, type, term, + if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, type, term, &matchoff, &matchlen) <= 0) return -ENOENT; - return mangle_packet(skb, dptr, datalen, matchoff, matchlen, + return mangle_packet(skb, dataoff, dptr, datalen, matchoff, matchlen, buffer, buflen) ? 0 : -EINVAL; } -static unsigned int ip_nat_sdp_addr(struct sk_buff *skb, const char **dptr, - unsigned int dataoff, - unsigned int *datalen, +static unsigned int ip_nat_sdp_addr(struct sk_buff *skb, 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) @@ -344,16 +384,15 @@ static unsigned int ip_nat_sdp_addr(struct sk_buff *skb, const char **dptr, unsigned int buflen; buflen = sprintf(buffer, "%pI4", &addr->ip); - if (mangle_sdp_packet(skb, dptr, dataoff, datalen, type, term, + if (mangle_sdp_packet(skb, dataoff, dptr, datalen, sdpoff, type, term, buffer, buflen)) return 0; - return mangle_content_len(skb, dptr, datalen); + return mangle_content_len(skb, dataoff, dptr, datalen); } -static unsigned int ip_nat_sdp_port(struct sk_buff *skb, - const char **dptr, - unsigned int *datalen, +static unsigned int ip_nat_sdp_port(struct sk_buff *skb, unsigned int dataoff, + const char **dptr, unsigned int *datalen, unsigned int matchoff, unsigned int matchlen, u_int16_t port) @@ -362,16 +401,16 @@ static unsigned int ip_nat_sdp_port(struct sk_buff *skb, unsigned int buflen; buflen = sprintf(buffer, "%u", port); - if (!mangle_packet(skb, dptr, datalen, matchoff, matchlen, + if (!mangle_packet(skb, dataoff, dptr, datalen, matchoff, matchlen, buffer, buflen)) return 0; - return mangle_content_len(skb, dptr, datalen); + return mangle_content_len(skb, dataoff, dptr, datalen); } -static unsigned int ip_nat_sdp_session(struct sk_buff *skb, const char **dptr, - unsigned int dataoff, - unsigned int *datalen, +static unsigned int ip_nat_sdp_session(struct sk_buff *skb, unsigned int dataoff, + const char **dptr, unsigned int *datalen, + unsigned int sdpoff, const union nf_inet_addr *addr) { char buffer[sizeof("nnn.nnn.nnn.nnn")]; @@ -379,12 +418,12 @@ static unsigned int ip_nat_sdp_session(struct sk_buff *skb, const char **dptr, /* Mangle session description owner and contact addresses */ buflen = sprintf(buffer, "%pI4", &addr->ip); - if (mangle_sdp_packet(skb, dptr, dataoff, datalen, + if (mangle_sdp_packet(skb, dataoff, dptr, datalen, sdpoff, SDP_HDR_OWNER_IP4, SDP_HDR_MEDIA, buffer, buflen)) return 0; - switch (mangle_sdp_packet(skb, dptr, dataoff, datalen, + switch (mangle_sdp_packet(skb, dataoff, dptr, datalen, sdpoff, SDP_HDR_CONNECTION_IP4, SDP_HDR_MEDIA, buffer, buflen)) { case 0: @@ -401,14 +440,13 @@ static unsigned int ip_nat_sdp_session(struct sk_buff *skb, const char **dptr, return 0; } - return mangle_content_len(skb, dptr, datalen); + return mangle_content_len(skb, 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 ip_nat_sdp_media(struct sk_buff *skb, - const char **dptr, - unsigned int *datalen, +static unsigned int ip_nat_sdp_media(struct sk_buff *skb, unsigned int dataoff, + const char **dptr, unsigned int *datalen, struct nf_conntrack_expect *rtp_exp, struct nf_conntrack_expect *rtcp_exp, unsigned int mediaoff, @@ -456,7 +494,8 @@ static unsigned int ip_nat_sdp_media(struct sk_buff *skb, /* Update media port. */ if (rtp_exp->tuple.dst.u.udp.port != rtp_exp->saved_proto.udp.port && - !ip_nat_sdp_port(skb, dptr, datalen, mediaoff, medialen, port)) + !ip_nat_sdp_port(skb, dataoff, dptr, datalen, + mediaoff, medialen, port)) goto err2; return NF_ACCEPT; @@ -471,6 +510,7 @@ err1: static void __exit nf_nat_sip_fini(void) { rcu_assign_pointer(nf_nat_sip_hook, NULL); + rcu_assign_pointer(nf_nat_sip_seq_adjust_hook, NULL); rcu_assign_pointer(nf_nat_sip_expect_hook, NULL); rcu_assign_pointer(nf_nat_sdp_addr_hook, NULL); rcu_assign_pointer(nf_nat_sdp_port_hook, NULL); @@ -482,12 +522,14 @@ static void __exit nf_nat_sip_fini(void) static int __init nf_nat_sip_init(void) { BUG_ON(nf_nat_sip_hook != NULL); + BUG_ON(nf_nat_sip_seq_adjust_hook != NULL); BUG_ON(nf_nat_sip_expect_hook != NULL); BUG_ON(nf_nat_sdp_addr_hook != NULL); BUG_ON(nf_nat_sdp_port_hook != NULL); BUG_ON(nf_nat_sdp_session_hook != NULL); BUG_ON(nf_nat_sdp_media_hook != NULL); rcu_assign_pointer(nf_nat_sip_hook, ip_nat_sip); + rcu_assign_pointer(nf_nat_sip_seq_adjust_hook, ip_nat_sip_seq_adjust); rcu_assign_pointer(nf_nat_sip_expect_hook, ip_nat_sip_expect); rcu_assign_pointer(nf_nat_sdp_addr_hook, ip_nat_sdp_addr); rcu_assign_pointer(nf_nat_sdp_port_hook, ip_nat_sdp_port); |