On 1/17/2019 6:56 PM, Guy Harris wrote: > On Jan 17, 2019, at 2:39 PM, Florian Fainelli <f.faine...@gmail.com> wrote: > >> DSA currently supports the following tagging protocols (details can be >> found under net/dsa/tag_*.c in Linux source for exactly length and offset >> within the Ethernet frame): > > Unfortunately, tag_brcm.c, for example, doesn't give *enough* details - it > has a bunch of uncommented #defines (some of which suggest overlap between > fields in the same byte of the tag) and some code that doesn't handle all the > fields in both ingress and egress tags. > > Can you construct "ASCII-art" diagrams and explanatory text, of the sort seen > in, for example: > > http://www.tcpdump.org/linktypes/LINKTYPE_LINUX_SLL.html > > for the tags?
Most certainly, I can only answer for the Broadcom tags, since I am not very familiar with the other protocols, and I am hoping someone else could fill in for Intel/Qualcomm/Mediatek etc. We have two different formats, presented below. Let me know if you need more details on each field and I can expand. Egress (switch to management port) format: +----------------------------------------------------------+ | Ethernet Destination address (6 octets) | +----------------------------------------------------------+ +----------------------------------------------------------+ | Ethernet Source address (6 octets) | +----------------------------------------------------------+ +----------------------------------------------------------+ | OPcode[7:5] | Traffic class[4:2] | Tag enforcement [1:0] | +----------------------------------------------------------+ | Time stamp [7] | Unused | +----------------------------------------------------------+ +----------------------------------------------------------+ | Reserved [7:1] | Desination map[1]| +----------------------------------------------------------+ +----------------------------------------------------------+ | Destination map [7:0] | +----------------------------------------------------------+ +----------------------------------------------------------+ | Ethernet Type/Length (2 bytes) | +----------------------------------------------------------+ +----------------------------------------------------------+ | Ethernet payload | . . . . . . Ingress (management port to switch) format +----------------------------------------------------------+ | Ethernet Destination address (6 octets) | +----------------------------------------------------------+ +----------------------------------------------------------+ | Ethernet Source address (6 octets) | +----------------------------------------------------------+ +----------------------------------------------------------+ | OPcode[7:5] | Reserved[4:0] | +----------------------------------------------------------+ | Classification ID [7:0] | +----------------------------------------------------------+ +----------------------------------------------------------+ | Reason code [7:0] | +----------------------------------------------------------+ +----------------------------------------------------------+ | Traffic class [7:5] | Source port number [4:0] | +----------------------------------------------------------+ +----------------------------------------------------------+ | Ethernet Type/Length (2 bytes) | +----------------------------------------------------------+ +----------------------------------------------------------+ | Ethernet payload | . . . . . . -- Florian _______________________________________________ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
