From 7266507d89991fa1e989283e4e032c6d9357fe26 Mon Sep 17 00:00:00 2001 From: Kevin Cernekee Date: Mon, 17 Dec 2012 18:33:58 +0000 Subject: netfilter: nf_ct_sip: support Cisco 7941/7945 IP phones 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 Acked-by: Eric Dumazet Cc: Patrick McHardy Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_sip.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'net/netfilter/nf_conntrack_sip.c') diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index df8f4f284481..72a67bbe3518 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; -- cgit v1.2.3