[OpenSER-Devel] [ openser-Bugs-1816565 ] Automatic mangling of Contact header and SDP in mhomed mode

Fri Oct 19 16:44:04 CEST 2007

Bugs item #1816565, was opened at 2007-10-19 16:18
Message generated for change (Comment added) made by klaus_darilion
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Category: core
Group: ver devel
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Ovidiu Sas (osas)
Assigned to: Nobody/Anonymous (nobody)
Summary: Automatic mangling of Contact header and SDP in mhomed mode

Initial Comment:
Strange behavior for openser 1.3 in mhomed mode (automatic mangling of Contact header and c= line of SDP)

I was playing with openser 1.3 in a multihomed setup.
In this setup, I noticed that by default, openser is mangling the Contact header and the sdp.
I stripped down the config to bare minimum to see if it was something related to my config, but it seems that this is not related to the config.

Here's the stripped down config that I used:
# ----------- global configuration parameters ------------------------
debug=3
fork=yes
log_stderror=no

check_via=no    # (cmd. line: -v)
dns=no          # (cmd. line: -r)
rev_dns=no      # (cmd. line: -R)
auto_aliases=no
listen=udp:br0
listen=udp:eth1
children=1
mhomed=1
disable_tcp=yes
disable_dns_blacklist=true

# ------------------ module loading ----------------------------------
mpath="/opt/lib/openser/modules"

loadmodule "sl.so"

loadmodule "tm.so"
# -- tm params --
modparam("tm", "fr_inv_timer", 100)
modparam("tm", "fr_inv_timer_avp", "$avp(i:26)")
modparam("tm", "fr_timer", 10)
modparam("tm", "fr_timer_avp", "$avp(i:25)")
modparam("tm", "noisy_ctimer", 1)
modparam("tm", "onreply_avp_mode", 1)

loadmodule "rr.so"

# --- request routing logic -----

# main routing logic

route{
        if (!method=="REGISTER") {
                record_route();
        }

        if (loose_route()) {
                route(1);
        };

        if (!uri==myself) {
                route(1);
        };

        if (uri==myself) {
                sl_send_reply("404", "Not Found");
                exit;
        };

        route(1);
}

route[1] {
        if (!t_relay()) {
                sl_reply_error();
        };
        exit;
}

Here's the network setup:

<asterisk box> --- <         openser         > --- <SIP server>
<192.168.2.20> --- <192.168.2.1 : EXTERNAL_IP> --- <SIP_SERVER>

And here's an ngrep of the initial INVITEs:
23:53:31.439678 IP 192.168.2.20.sip > 192.168.2.1.sip: SIP, length: 819
INVITE sip:callee at SIP_SERVER SIP/2.0
Via: SIP/2.0/UDP 192.168.2.20:5060;branch=z9hG4bK4f70ea70
From: "Ovi Sas" <sip:caller at SIP_SERVER>;tag=as048c5bed
To: <sip:callee at SIP_SERVER>
Contact: <sip:caller at 192.168.2.20>
Call-ID: 28aedce563bc57dc2cac78967e69c141 at SIP_SERVER
CSeq: 102 INVITE
User-Agent: asterisk
Max-Forwards: 70
Date: Thu, 18 Oct 2007 04:23:04 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: 285

v=0
o=root 8560 8560 IN IP4 192.168.2.20
s=session
c=IN IP4 192.168.2.20
t=0 0
m=audio 34028 RTP/AVP 0 3 8 101
a=rtpmap:0 PCMU/8000
a=rtpmap:3 GSM/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=silenceSupp:off - - - -
a=ptime:20
a=sendrecv

23:53:31.454727 IP EXTERNAL_IP.sip > SIP_SERVER.sip: SIP, length: 1011
INVITE sip:callee at SIP_SERVER SIP/2.0
Record-Route: <sip:EXTERNAL_IP;r2=on;lr;ftag=as048c5bed>
Record-Route: <sip:192.168.2.1;r2=on;lr;ftag=as048c5bed>
Via: SIP/2.0/UDP EXTERNAL_IP:5060;branch=z9hG4bKea4e.7aacc885.0
Via: SIP/2.0/UDP 192.168.2.20:5060;branch=z9hG4bK4f70ea70
From: "Ovi Sas" <sip:caller at SIP_SERVER>;tag=as048c5bed
To: <sip:callee at SIP_SERVER>
Contact: <sip:caller at EXTERNAL_IP:5060>
Call-ID: 28aedce563bc57dc2cac78967e69c141 at SIP_SERVER
CSeq: 102 INVITE
User-Agent: asterisk
Max-Forwards: 70
Date: Thu, 18 Oct 2007 04:23:04 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: 286

v=0
o=root 8560 8560 IN IP4 192.168.2.20
s=session
c=IN IP4 EXTERNAL_IP
t=0 0
m=audio 34028 RTP/AVP 0 3 8 101
a=rtpmap:0 PCMU/8000
a=rtpmap:3 GSM/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=silenceSupp:off - - - -
a=ptime:20
a=sendrecv

Please note the Contact header and the c= line inside SDP.

Is there a way to bypass this behaviour?
Using the nathelper module doesn't seem to help (the Contact header will still carry the EXTERNAL_IP.

Regards,
Ovidiu Sas

http://openser.org/pipermail/users/2007-October/013819.html

----------------------------------------------------------------------

>Comment By: Klaus Darilion (klaus_darilion)
Date: 2007-10-19 16:44

Message:
Logged In: YES 
user_id=1318360
Originator: NO

I'm quite sure openser never changes Contact/SDP except when told to do
so. Some time ago someone had the same problem which was caused by Linux
netfilter sip_conntrack module. Make sure you do not have something similar
activated.

----------------------------------------------------------------------

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