Re: [tcpdump-workers] [RFC] Addition of link-layer header types for PCI, PCI-X, and PCI-Express
--- Begin Message --- On Sat, Oct 24, 2020 at 5:32 PM Michael Richardson wrote: > > > Aki Van Ness wrote: > > Yeah it might be possible to use something like a single DLT. The issue > > I can possibly forsee with that is PCI, PCI-X, and PCI-Express are all > > slightly different enough to be a pain to group together into a single > > structure. > > > It might be better to have either each type be its own DLT or if it > > must be one DLT a layered approach with a meta-header of sorts that > > just describes some of the generic information about the link, like > > it's type, etc. then have a sub-section whose interpretation is > > dependent on the link type. > > > I'm more partial towards the former than the latter personally, but I > > understand not wanting to add a bunch of DLTs at once. > > If you prefer to use three/four DLTs, that's probably not a problem. > If you wind up needing 20, then a distinguished union is probably a better > solution. (uhm. "distinguished union" seems not the be term I want) > A layered solution. > > https://github.com/the-tcpdump-group/libpcap/blob/master/doc/DLT_ALLOCATE_HOWTO.md > Okay, that sounds fair. Would the best thing for me to do is to just spin up a PR for libpcap to add the DLTs / Link types as PoC and get feedback there? --- End Message --- ___ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
Re: [tcpdump-workers] [RFC] Addition of link-layer header types for PCI, PCI-X, and PCI-Express
--- Begin Message --- On Oct 21, 2020, at 1:56 PM, Aki Van Ness via tcpdump-workers wrote: > I'm working on a project that plans to store PCI and PCI-Express > packets in the pcapng format as that's the most appropriate storage > format and I really rather not roll something custom. > > As such what are thoughts on adding Link-Layer types for PCI, PCI-X, > and PCI-Express? It seems reasonable, given that we have USB, Infiniband, and the DisplayPort AUX channel. > And would you want to group all versions of PCI, PCI-X, and > PCI-Express together or have them be their own values? Would each version need its own LINKTYPE_ value, or would a single metadata header and payload suffice for all versions of PCI, all versions of PCI-X, and all versions of PCIe? From a quick look at the Wikipedia pages for those, for what that's worth, they changes for each seem to be at the physical layer, with full or at least significant backwards compatibility, so, other than additional bits of metadata, would LINKTYPE_PCI, LINKTYPE_PCI_X, and LINKTYPE_PCI_EXPRESS suffice? I'm assuming that the metadata would be different between PCI, PCI-X, and PCIe. --- End Message --- ___ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
