[PATCH net-next 0/3] seg6_local: add USP and USD flavors support (RFC 8986)

[Minhong He]

RFC 8986 defines the PSP, USP and USD flavors for the SRv6 End
behaviors. Currently, the Linux SRv6 implementation (seg6_local)
only supports the PSP flavor (combined with the NEXT-C-SID
flavor).

This patch series adds support for the USP (Ultimate Segment Pop
of the SRH) flavor to the End, End.X and End.T behaviors, and for
the USD (Ultimate Segment Decapsulation) flavor to the SRv6 End
behaviors that perform the decapsulation of the packet (i.e.,
End.DX4, End.DX6, End.DT4, End.DT6, End.DT46).

Patch overview:

- Patch 1 implements the USP flavor for the End behavior by
  extending the RFC 8986 flavor action table with the entries
  required to process the combinations of packet info and the USP
  flavor (either alone or combined with the PSP flavor);

- Patch 2 adds the USD flavor support to the decap behaviors.
  Since these behaviors already remove the outer IPv6 header (and,
  as a consequence, the SRH too) as part of the decapsulation
  process, the USD flavor is only supported at the control plane
  level, to ease the interoperability with control planes (e.g.,
  IS-IS, BGP-LS) which can advertise SIDs with the USD flavor;

- Patch 3 extends the USP flavor support to the End.X and End.T
  behaviors, which can now take advantage of the flavor action
  table mechanism introduced in patch 1.

The series has been applied and tested on top of linux-next
(next-20261102).

Minhong He (3):
  seg6_local: implement USP flavor for the End behavior
  seg6_local: support USD flavor for decap behaviors
  seg6_local: add USP flavor support to End.X and End.T

 net/ipv6/seg6_local.c | 163 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 143 insertions(+), 20 deletions(-)

-- 
2.25.1