[fpc-pascal] Help Reading SIP Messages.

[lloyd thomas]

Please forgive my ignorance regarding the project I am about to embark on.
Need some advice on Lnet and capturing SIP RTP data to file. In the first
instance I just need to work with the sip messages. I believe the SIP
messages are similar to HTTP. I am using wireshark to understand how the SIP
messages are processed, but I am not sure how to capture and read each frame
(wireshark speak) using Lnet.

(FYI:
http://en.wikipedia.org/wiki/Session_Initiation_Protocol#SIP_network_elements
)

For instance the following is from frame 12 (935 bytes)
----------------------------------------------------------------------------------------------
INVITE sip:1002 at 192.168.91.200 <sip%3A1002 at 192.168.91.200> SIP/2.0
Via:SIP/2.0/UDP 192.168.91.190:5060;rport;branch=z9hG4bK83570061
From:"Lloyd" <sip:1000 at 192.168.91.200 <sip%3A1000 at 192.168.91.200>
>;tag=4b428357-2fa-1ec5d4e
To:<sip:1002 at 192.168.91.200 <sip%3A1002 at 192.168.91.200>>
Contact:"Lloyd" <sip:1000 at 192.168.91.190:5060;transport=UDP>
Call-ID:83570000-4ce59f27 at 192.168.91.200<Call-ID%3A83570000-4ce59f27 at 192.168.91.200>
Subject:sip phone call
CSeq:2112045024 INVITE
User-Agent:Mitel-5212-SIP-Phone 07.02.00.04 08000F24BEE5
Allow:INVITE,ACK,CANCEL,BYE,OPTIONS,REFER,NOTIFY,PRACK,UPDATE
Allow-Events:talk,hold,conference
Supported:timer,100rel,replaces
Session-Expires: 1800
Min-SE: 90
Max-Forwards:70
Content-Type:application/sdp
Content-Length:247

v=0
o=1000 1262650963 1262650962 IN IP4 192.168.91.190
s=SIP Call
c=IN IP4 192.168.91.190
t=0 0
a=sendrecv
m=audio 20036 RTP/AVP 0 8 18 96
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:18 G729/8000
a=rtpmap:96 telephone-event/8000
-----------------------------------------------------------------------------------------------

I get a response from the sip server on frame 13 (371 bytes)
----------------------------------------------------------------------------------------------
SIP/2.0 100 Trying
Via: SIP/2.0/UDP 192.168.91.190:5060;rport=5060;branch=z9hG4bK83570061
From: "Lloyd" <sip:1000 at 192.168.91.200 <sip%3A1000 at 192.168.91.200>
>;tag=4b428357-2fa-1ec5d4e
To: <sip:1002 at 192.168.91.200 <sip%3A1002 at 192.168.91.200>>
Call-ID: 83570000-4ce59f27 at 192.168.91.200
CSeq: 2112045024 INVITE
User-Agent: FreeSWITCH-mod_sofia/1.0.trunk-15355M
Content-Length: 0
-----------------------------------------------------------------------------------------------
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