From patchwork Mon Dec 17 00:17:21 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 206755 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 6C8E12C00A6 for ; Mon, 17 Dec 2012 11:18:15 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752006Ab2LQAR5 (ORCPT ); Sun, 16 Dec 2012 19:17:57 -0500 Received: from merlin.infradead.org ([205.233.59.134]:45475 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751368Ab2LQARz (ORCPT ); Sun, 16 Dec 2012 19:17:55 -0500 Received: from shinybook.infradead.org ([2001:8b0:10b:1:e6ce:8fff:fe1f:f2c0]) by merlin.infradead.org with esmtpsa (Exim 4.76 #1 (Red Hat Linux)) id 1TkOOf-0004MP-8e; Mon, 17 Dec 2012 00:17:29 +0000 Message-ID: <1355703441.18919.6.camel@shinybook.infradead.org> Subject: Re: [PATCH v3] netfilter: nf_conntrack_sip: Handle Cisco 7941/7945 IP phones From: David Woodhouse To: Eric Dumazet Cc: Kevin Cernekee , Patrick McHardy , "David S. Miller" , Alexey Kuznetsov , "Pekka Savola (ipv6)" , James Morris , Hideaki YOSHIFUJI , netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org, coreteam@netfilter.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Date: Mon, 17 Dec 2012 00:17:21 +0000 In-Reply-To: <1290412334.2756.141.camel@edumazet-laptop> References: <1290412334.2756.141.camel@edumazet-laptop> X-Mailer: Evolution 3.6.2 (3.6.2-3.fc18) Mime-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 2010-11-22 at 08:52 +0100, Eric Dumazet wrote: > Le dimanche 21 novembre 2010 à 18:40 -0800, Kevin Cernekee a écrit : > > [v3: > > Only activate the new forced_dport logic if the IP matches, but the > > port does not. ] > > > > Most SIP devices use a source port of 5060/udp on SIP requests, so the > > response automatically comes back to port 5060: > > > > phone_ip:5060 -> proxy_ip:5060 REGISTER > > proxy_ip:5060 -> phone_ip:5060 100 Trying > > > > The newer Cisco IP phones, however, use a randomly chosen high source > > port for the SIP request but expect the response on port 5060: > > > > phone_ip:49173 -> proxy_ip:5060 REGISTER > > proxy_ip:5060 -> phone_ip:5060 100 Trying > > > > Standard Linux NAT, with or without nf_nat_sip, will send the reply back > > to port 49173, not 5060: > > > > phone_ip:49173 -> proxy_ip:5060 REGISTER > > proxy_ip:5060 -> phone_ip:49173 100 Trying > > > > But the phone is not listening on 49173, so it will never see the reply. > > > > This patch modifies nf_*_sip to work around this quirk by extracting > > the SIP response port from the Via: header, iff the source IP in the > > packet header matches the source IP in the SIP request. > > > > Signed-off-by: Kevin Cernekee > > --- > > Thanks for doing this work Keven ! > > Acked-by: Eric Dumazet What happened to this? OpenWRT is still carrying it, and it broke in 3.7. Here's a completely untested update... + if (!skb_make_writable(skb, skb->len)) + return NF_DROP; + -+ uh = (struct udphdr *)(skb->data + ip_hdrlen(skb)); ++ uh = (void *)skb->data + protoff; + uh->dest = ct_sip_info->forced_dport; + -+ if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, 0, 0, NULL, 0)) ++ if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff, 0, 0, NU + return NF_DROP; + } + return NF_ACCEPT; } diff --git a/include/linux/netfilter/nf_conntrack_sip.h b/include/linux/netfilter/nf_conntrack_sip.h index 387bdd0..ba7f571 100644 --- a/include/linux/netfilter/nf_conntrack_sip.h +++ b/include/linux/netfilter/nf_conntrack_sip.h @@ -4,12 +4,15 @@ #include +#include + #define SIP_PORT 5060 #define SIP_TIMEOUT 3600 struct nf_ct_sip_master { unsigned int register_cseq; unsigned int invite_cseq; + __be16 forced_dport; }; enum sip_expectation_classes { diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index df8f4f2..72a67bb 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1440,8 +1440,25 @@ static int process_sip_request(struct sk_buff *skb, unsigned int protoff, { enum ip_conntrack_info ctinfo; struct nf_conn *ct = nf_ct_get(skb, &ctinfo); + struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct); + enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); unsigned int matchoff, matchlen; unsigned int cseq, i; + union nf_inet_addr addr; + __be16 port; + + /* Many Cisco IP phones use a high source port for SIP requests, but + * listen for the response on port 5060. If we are the local + * router for one of these phones, save the port number from the + * Via: header so that nf_nat_sip can redirect the responses to + * the correct port. + */ + if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, + SIP_HDR_VIA_UDP, NULL, &matchoff, + &matchlen, &addr, &port) > 0 && + port != ct->tuplehash[dir].tuple.src.u.udp.port && + nf_inet_addr_cmp(&addr, &ct->tuplehash[dir].tuple.src.u3)) + ct_sip_info->forced_dport = port; for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) { const struct sip_handler *handler; diff --git a/net/netfilter/nf_nat_sip.c b/net/netfilter/nf_nat_sip.c index 16303c7..552e270 100644 --- a/net/netfilter/nf_nat_sip.c +++ b/net/netfilter/nf_nat_sip.c @@ -95,6 +95,7 @@ static int map_addr(struct sk_buff *skb, unsigned int protoff, 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; @@ -107,7 +108,8 @@ static int map_addr(struct sk_buff *skb, unsigned int protoff, } 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->tuplehash[!dir].tuple.src.u.udp.port; + newport = ct_sip_info->forced_dport ? ct_sip_info->forced_dport : + ct->tuplehash[!dir].tuple.src.u.udp.port; } else return 1; @@ -144,6 +146,7 @@ static unsigned int nf_nat_sip(struct sk_buff *skb, unsigned int protoff, 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; @@ -258,6 +261,20 @@ next: !map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_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)) + 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)) + return NF_DROP; + } + return NF_ACCEPT; } @@ -311,8 +328,10 @@ static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff, 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; @@ -326,8 +345,9 @@ static unsigned int nf_nat_sip_expect(struct sk_buff *skb, unsigned int protoff, /* If the signalling port matches the connection's source port in the * original direction, try to use the destination port in the opposite * direction. */ - if (exp->tuple.dst.u.udp.port == - ct->tuplehash[dir].tuple.src.u.udp.port) + srcport = ct_sip_info->forced_dport ? 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);