tcpdump mailing list archives
DLT assignment request
From: Stephen Donnelly <stephen () endace com>
Date: Thu, 26 Jul 2007 08:57:45 +1200
I have sent this to the tcpdump-workers list but there is no response yet so I will copy it here as it impacts Wireshark also. Libpcap supports live capture from Endace DAG cards from wide variety of network link types. For example a capture natively using the Endace ERF TYPE_HDLC_POS type can select DLT_CHDLC, DLT_PPP_SERIAL, DLT_FRELAY, DLT_MTP2, or DLT_MTP2_WITH_PHDR depending on the nature of the actual link. Florent Drouin from Alcatel-Lucent has been working on improving the ERF support in Wireshark. As part of this work we would like to request a new DLT (DLT_ERF) which would encapsulate a single ERF record of any ERF type. DLT_ERF would be available in addition to the existing DLT choices. Forthcoming patches for Wireshark will allow it to completely decode this type, including all of the ERF pseudoheader information. As the DLT_ERF could encapsulate a variety of link types we would not support BPF filtering of DLT_ERF records, at least initially. Wireshark 'display filters' will be able to act on this pcap type and also when reading directly from ERF format files. The only alternative I can see would be assigning new DLTs on a 1:1 basis with ERF types, however there are already 19 ERF types defined and I feel this would unnecessarily consume/pollute the libpcap DLT namespace. Comments, questions, objections welcome. Regards, Stephen. -- ----------------------------------------------------------------------- Stephen Donnelly BCMS PhD email: sfd () endace com Endace Technology Ltd phone: +64 7 839 0540 Hamilton, New Zealand cell: +64 21 1104378 ----------------------------------------------------------------------- - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.
Current thread:
- DLT assignment request Stephen Donnelly (Jul 23)
- <Possible follow-ups>
- DLT assignment request Stephen Donnelly (Jul 30)
- Re: DLT assignment request Guy Harris (Aug 07)
- Re: DLT assignment request Stephen Donnelly (Aug 07)
- Re: DLT assignment request Guy Harris (Aug 07)