From: Kevin Cernekee <cernekee@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Patrick McHardy <kaber@trash.net>,
"David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
"Pekka Savola (ipv6)" <pekkas@netcore.fi>,
James Morris <jmorris@namei.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org,
coreteam@netfilter.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org
Subject: Re: [PATCH/RFC] netfilter: nf_conntrack_sip: Handle quirky Cisco phones
Date: Sun, 14 Nov 2010 10:33:06 -0800 [thread overview]
Message-ID: <AANLkTik4PLga8mX73c8iONPeOtpDiuDhfu3xiPmF07jC@mail.gmail.com> (raw)
In-Reply-To: <1289725175.2743.65.camel@edumazet-laptop>
On Sun, Nov 14, 2010 at 12:59 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> I would like to get an exact SIP exchange to make sure their is not
> another way to handle this without adding a "Cisco" string somewhere...
>
> Please provide a pcap or tcpdump -A
Existing nf_nat_sip: phone sends unauthenticated REGISTER requests
over and over again, because it is not seeing the replies sent back to
port 50070:
10:05:53.496479 IP 192.168.2.28.50070 > 67.215.241.250.5060: SIP, length: 723
E`...[..@.r.....C...........REGISTER sip:losangeles.voip.ms SIP/2.0
Via: SIP/2.0/
10:05:53.587370 IP 67.215.241.250.5060 > 192.168.2.28.50070: SIP, length: 486
E.......3..fC...............SIP/2.0 100 Trying
Via: SIP/2.0/UDP 192.168.2.28:5060
10:05:53.587807 IP 67.215.241.250.5060 > 192.168.2.28.50070: SIP, length: 550
E..B....3..%C...............SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 192.168.2.2
10:05:57.496541 IP 192.168.2.28.50070 > 67.215.241.250.5060: SIP, length: 723
E`...\..@.r.....C...........REGISTER sip:losangeles.voip.ms SIP/2.0
Via: SIP/2.0/
10:05:57.526716 IP 67.215.241.250.5060 > 192.168.2.28.50070: SIP, length: 486
E.......3..dC...............SIP/2.0 100 Trying
Via: SIP/2.0/UDP 192.168.2.28:5060
10:05:57.527162 IP 67.215.241.250.5060 > 192.168.2.28.50070: SIP, length: 550
E..B....3..#C...............SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 192.168.2.2
10:06:01.486821 IP 192.168.2.28.50070 > 67.215.241.250.5060: SIP, length: 723
E`...]..@.r.....C...........REGISTER sip:losangeles.voip.ms SIP/2.0
Via: SIP/2.0/
10:06:01.515611 IP 67.215.241.250.5060 > 192.168.2.28.50070: SIP, length: 486
E.......3..bC...............SIP/2.0 100 Trying
Via: SIP/2.0/UDP 192.168.2.28:5060
10:06:01.516024 IP 67.215.241.250.5060 > 192.168.2.28.50070: SIP, length: 550
E..B....3..!C...............SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 192.168.2.2
... continues forever ...
Patched nf_nat_sip: router sends the replies back to port 5060, so the
phone is now able to register itself and make calls:
10:09:46.221631 IP 192.168.2.28.50618 > 67.215.241.250.5060: SIP, length: 723
E`...G..@.p.....C...........REGISTER sip:losangeles.voip.ms SIP/2.0
Via: SIP/2.0/
10:09:46.253052 IP 67.215.241.250.5060 > 192.168.2.28.5060: SIP, length: 491
E....+..4..$C...............SIP/2.0 100 Trying
Via: SIP/2.0/UDP 192.168.2.28:5060
10:09:46.253472 IP 67.215.241.250.5060 > 192.168.2.28.5060: SIP, length: 550
E..B.,..4...C...............SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 192.168.2.2
10:09:46.261602 IP 192.168.2.28.50618 > 67.215.241.250.5060: SIP, length: 900
E`...H..@.p.....C...........REGISTER sip:losangeles.voip.ms SIP/2.0
Via: SIP/2.0/
10:09:46.290211 IP 67.215.241.250.5060 > 192.168.2.28.5060: SIP, length: 491
E....-..4.."C...............SIP/2.0 100 Trying
Via: SIP/2.0/UDP 192.168.2.28:5060
10:09:46.295041 IP 67.215.241.250.5060 > 192.168.2.28.5060: SIP, length: 579
E.._....4...C............K..SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.2.28:5060;bra
BTW, I thought of two possible issues with the original patch:
1) Might need to call skb_make_writable() prior to modifying the
packet. Presumably the second invocation inside
nf_nat_mangle_udp_packet() will have no effect.
(Is there a cleaner way to mangle just the port number? Most of the
utility functions only help with modifying the data area.)
2) I should probably be checking to make sure request == 0 before
mangling the packet. The current behavior is harmless if the SIP
proxy is on port 5060, but that might not always be the case.
I can roll these, along with any other suggestions, into v2.
next prev parent reply other threads:[~2010-11-14 18:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-14 8:32 [PATCH/RFC] netfilter: nf_conntrack_sip: Handle quirky Cisco phones Kevin Cernekee
2010-11-14 8:59 ` Eric Dumazet
2010-11-14 18:33 ` Kevin Cernekee [this message]
2010-11-14 19:57 ` Eric Dumazet
2010-11-15 3:01 ` Kevin Cernekee
2010-11-15 10:15 ` Patrick McHardy
2010-11-15 16:46 ` Kevin Cernekee
2010-11-15 16:58 ` Patrick McHardy
2010-11-15 22:09 ` Kevin Cernekee
2010-11-15 9:51 ` Patrick McHardy
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