![]() ![]() #Voip wireshark pcap code#If you are 150 % sure that the SIP part of your VoIP traffic uses solely non-fragmented UDP packets as transport, the Lua code below is what you asked for, except that I haven't tested it on captures containing RTCP or T.38 packets.įragmentation of SIP packets as well as use of TCP as SIP transport renders it unusable, because the way it is written, the listener always receives only the last fragment of reassembled SIP PDUs, regardless whether they have been reassembled from IP fragments or TCP segments (or both), because the SIP dissector is invoked only when processing the reassembled transport layer. I've never collected enough motivation to write a Lua listener, and now I know why. So you'll get just the beginning of calls spanning multiple source files.Īnother limitation is that if the telephony engine of Wireshark fails to detect an RTP stream for whatever reason, you miss it too.Īnd yet another limitation is that if the traffic contains some complex scenarios like call transfers, or if there is just a B2BUA which decouples the Call-IDs between two branches of the same actual call, you'll have to merge several output files together to get everything related into a single file. This way you'll save all calls whose initial INVITE is present in that capture calls which had already been running when the capture started will be ignored. Register your tap to get all SIP, RTP and udptl packetsĬreate a new output file with each new SIP Call-ID value you extract from an incoming SIP INVITE packet with no To-tag, and maintain a table mapping the Call-ID values to file namesĬopy each SIP packet bearing that Call-ID to the corresponding file, and if it contains an SDP, create a row in a table frame2callid where the value is the Call-ID or the file handle associated to it and the index is the frame numberįor each RTP (or udptl) packet, use the rt.setup-frame value as an index to the frame2callid table to learn where (to which file) to copy it (and ignore RTP packets which don't have that value).Īt the end of the capture, close all output files. If you have ever programmed anything, Lua is not that complex to learn, and the business logic is quite simple: line in its output?ĭoes the user under which you run Wireshark enough privileges to write into the destination directory? If you run tshark, can you see the Starting a script. If it is, does Wireshark complain about anything wrong about Lua? So what surprises me is that you say it does nothing at all, it should at least woe that the libraries are unavailable, or thatĪre your VoIP calls initiated using SIP or using another protocol (because the script doesn't deal with MGCP, H.323, or H.248/MEGACO)? So to work, it needs a library processing posix-compliant regular expressions and a library allowing to interface a database (both seem an overkill to me but that's another story).ĭuring runtime, the script creates a separate capture file for each VoIP call initiated using SIP and dumps to it all packets which belong to that call, based on the RTP and udptl (t38) dissectors' ability to identify the packet of a signalling protocol which contained the command setting up that particular RTP or udptl stream. sox is a command line audio tool for linux, I was using it to convert the raw audio into a wav.The Lua script you refer to says require "rex_pcre" so you'll need that or something like that. Maybe that will work better, since it's using the wireshark library (tshark) to filter out the audio from the pcap. A for loop is used to construct raw audio from the bytes here and then the script uses "sox" to convert the raw audio into a wav. the script uses Tshark to make the pcap, and then it's used again to filter the pcap for the rtp.ssrc field in the pcap. ![]() it's a linux tool, i have it installed on BSD as well as CentOS. #Voip wireshark pcap install#You'll need to install that on your system you're testing on. It makes use of tshark which is a command line version of wireshark. At the top of the link'ed article, you'll se the small bash script. It's basically doing the same thing programatically, but I never had an issue with audio quality with the bash script. That's where I started (before using Python.) I'll link my bash script here in this comment. ![]() If you need a quick solution that works, I'd suggest trying to do it as a bash script. ![]()
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