From: David S. Miller Date: Tue, 12 Oct 2021 10:49:50 +0000 (+0100) Subject: Merge branch 'ioam-fixes' X-Git-Tag: v5.15~92^2~17 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=7389074ced34091b12ca5ee65ceed9194224a7f6;p=mirror_ubuntu-kernels.git Merge branch 'ioam-fixes' Justin Iurman says: ==================== Correct the IOAM behavior for undefined trace type bits (@Jakub @David: there will be a conflict for #2 when merging net->net-next, due to commit [1]. The conflict is only 5-10 lines for #2 (#1 should be fine) inside the file tools/testing/selftests/net/ioam6.sh, so quite short though possibly ugly. Sorry for that, I didn't expect to post this one... Had I known, I'd have made the opposite.) Modify both the input and output behaviors regarding the trace type when one of the undefined bits is set. The goal is to keep the interoperability when new fields (aka new bits inside the range 12-21) will be defined. The draft [2] says the following: --------------------------------------------------------------- "Bit 12-21 Undefined. These values are available for future assignment in the IOAM Trace-Type Registry (Section 8.2). Every future node data field corresponding to one of these bits MUST be 4-octets long. An IOAM encapsulating node MUST set the value of each undefined bit to 0. If an IOAM transit node receives a packet with one or more of these bits set to 1, it MUST either: 1. Add corresponding node data filled with the reserved value 0xFFFFFFFF, after the node data fields for the IOAM-Trace-Type bits defined above, such that the total node data added by this node in units of 4-octets is equal to NodeLen, or 2. Not add any node data fields to the packet, even for the IOAM-Trace-Type bits defined above." --------------------------------------------------------------- The output behavior has been modified to respect the fact that "an IOAM encap node MUST set the value of each undefined bit to 0" (i.e., undefined bits can't be set anymore). As for the input behavior, current implementation is based on the second choice (i.e., "not add any data fields to the packet [...]"). With this solution, any interoperability is lost (i.e., if a new bit is defined, then an "old" kernel implementation wouldn't fill IOAM data when such new bit is set inside the trace type). The input behavior is therefore relaxed and these undefined bits are now allowed to be set. It is only possible thanks to the sentence "every future node data field corresponding to one of these bits MUST be 4-octets long". Indeed, the default empty value (the one for 4-octet fields) is inserted whenever an undefined bit is set. [1] cfbe9b002109621bf9a282a4a24f9415ef14b57b [2] https://datatracker.ietf.org/doc/html/draft-ietf-ippm-ioam-data#section-5.4.1 ==================== Signed-off-by: David S. Miller --- 7389074ced34091b12ca5ee65ceed9194224a7f6