Hi, has anyone had any luck with the dissector? I have a trace and already had a look at the dissector c code. But if a select "decode as" wireshark still just shows the normal udp data. I put a trace file on a webserver http://download.3imedia.de/Swyx/Tools/isdn.trace.pcapng.zip
in the source I found :
/ is ISDN packet? * the ISDN packets have 0x49446463 for packets from PSTN to the Blade and * 0x49644443 for packets from the Blade to the PSTN at offset 4 / isdn_header = tvb_get_ntohl(tvb, offset+4); if ( (tvb_len >= 50) && ( (isdn_header == PSTN_TO_BLADE) || (isdn_header == BLADE_TO_PSTN)) ) return ACTRACE_ISDN;
and a Display filter like
data[4:] contains 49:44:64:63 or data[4:] contains 49:64:44:43
works and returns all the pakets. But that is where I'm stuck. Is there any possbilty to debug the dissector? Or find out what is wrong with the trace or if it is a problem with the dissector?
asked 18 Mar '14, 03:52
edited 18 Mar '14, 09:59
somehow you need a plugin from audiocodes to work with this dissector. without it, it will not work.
answered 20 Mar '14, 06:20
edited 20 Mar '14, 06:54
The problem is that the magic 0x49644443 is at offset 19 in the UDP data payload, and not 4 as the heuristic expects. So the packets are not considered as valid AC packets.
answered 18 Mar '14, 15:26