From 48f8ac26537c1b7b1a2422f5232f45d06c945348 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 11 Feb 2010 12:29:38 +0100 Subject: [PATCH] netfilter: nf_nat_sip: add TCP support Add support for mangling TCP SIP packets. Signed-off-by: Patrick McHardy --- include/linux/netfilter/nf_conntrack_sip.h | 1 + net/ipv4/netfilter/nf_nat_sip.c | 53 +++++++++++++++++++--- net/netfilter/nf_conntrack_sip.c | 10 ++++ 3 files changed, 58 insertions(+), 6 deletions(-) diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h index fa9bb8981450..cd84d6f44d11 100644 --- a/include/linux/netfilter/nf_conntrack_sip.h +++ b/include/linux/netfilter/nf_conntrack_sip.h @@ -104,6 +104,7 @@ extern unsigned int (*nf_nat_sip_hook)(struct sk_buff *skb, unsigned int dataoff, const char **dptr, unsigned int *datalen); +extern void (*nf_nat_sip_seq_adjust_hook)(struct sk_buff *skb, s16 off); extern unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb, unsigned int dataoff, const char **dptr, diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c index b232e4040dc6..11b538deaaec 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 * based on RR's ip_nat_ftp.c and other modules. @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -36,10 +37,27 @@ static unsigned int mangle_packet(struct sk_buff *skb, unsigned int dataoff, { 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 + dataoff; @@ -104,6 +122,7 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff, struct nf_conn *ct = nf_ct_get(skb, &ctinfo); enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); unsigned int coff, matchoff, matchlen; + enum sip_header_types hdr; union nf_inet_addr addr; __be16 port; int request, in_header; @@ -120,9 +139,14 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff, } 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_UDP, 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")]; @@ -204,9 +228,23 @@ next: 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) @@ -472,6 +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); @@ -483,12 +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); diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index 1cc75c5a822b..3bb3aaff76e9 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -56,6 +56,9 @@ unsigned int (*nf_nat_sip_hook)(struct sk_buff *skb, unsigned int dataoff, unsigned int *datalen) __read_mostly; EXPORT_SYMBOL_GPL(nf_nat_sip_hook); +void (*nf_nat_sip_seq_adjust_hook)(struct sk_buff *skb, s16 off) __read_mostly; +EXPORT_SYMBOL_GPL(nf_nat_sip_seq_adjust_hook); + unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb, unsigned int dataoff, const char **dptr, @@ -1360,6 +1363,7 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff, const char *dptr, *end; s16 diff, tdiff = 0; int ret; + typeof(nf_nat_sip_seq_adjust_hook) nf_nat_sip_seq_adjust; if (ctinfo != IP_CT_ESTABLISHED && ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) @@ -1415,6 +1419,12 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff, datalen = datalen + diff - msglen; } + if (ret == NF_ACCEPT && ct->status & IPS_NAT_MASK) { + nf_nat_sip_seq_adjust = rcu_dereference(nf_nat_sip_seq_adjust_hook); + if (nf_nat_sip_seq_adjust) + nf_nat_sip_seq_adjust(skb, tdiff); + } + return ret; } -- 2.20.1