Re: [PATCH v3 resend] netfilter: nf_conntrack_sip: Handle Cisco 7941/7945IP phones

From: Pablo Neira Ayuso
Date: Thu May 26 2011 - 12:58:30 EST


Hi Eric,

On 20/05/11 06:36, Kevin Cernekee wrote:
> 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 <cernekee@xxxxxxxxx>
> Acked-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
> Cc: Patrick McHardy <kaber@xxxxxxxxx>

@Eric: could you please confirm that you ack'ed this patch? I don't find
the email with your explicit ack.
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