1. 16 Aug, 2023 1 commit
    • Andrea Mayer's avatar
      seg6: add NEXT-C-SID support for SRv6 End.X behavior · 7458575a
      Andrea Mayer authored
      The NEXT-C-SID mechanism described in [1] offers the possibility of
      encoding several SRv6 segments within a single 128 bit SID address. Such
      a SID address is called a Compressed SID (C-SID) container. In this way,
      the length of the SID List can be drastically reduced.
      
      A SID instantiated with the NEXT-C-SID flavor considers an IPv6 address
      logically structured in three main blocks: i) Locator-Block; ii)
      Locator-Node Function; iii) Argument.
      
                              C-SID container
      +------------------------------------------------------------------+
      |     Locator-Block      |Loc-Node|            Argument            |
      |                        |Function|                                |
      +------------------------------------------------------------------+
      <--------- B -----------> <- NF -> <------------- A --------------->
      
         (i) The Locator-Block can be any IPv6 prefix available to the provider;
      
        (ii) The Locator-Node Function represents the node and the function to
             be triggered when a packet is received on the node;
      
       (iii) The Argument carries the remaining C-SIDs in the current C-SID
             container.
      
      This patch leverages the NEXT-C-SID mechanism previously introduced in the
      Linux SRv6 subsystem [2] to support SID compression capabilities in the
      SRv6 End.X behavior [3].
      An SRv6 End.X behavior with NEXT-C-SID flavor works as an End.X behavior
      but it is capable of processing the compressed SID List encoded in C-SID
      containers.
      
      An SRv6 End.X behavior with NEXT-C-SID flavor can be configured to support
      user-provided Locator-Block and Locator-Node Function lengths. In this
      implementation, such lengths must be evenly divisible by 8 (i.e. must be
      byte-aligned), otherwise the kernel informs the user about invalid
      values with a meaningful error code and message through netlink_ext_ack.
      
      If Locator-Block and/or Locator-Node Function lengths are not provided
      by the user during configuration of an SRv6 End.X behavior instance with
      NEXT-C-SID flavor, the kernel will choose their default values i.e.,
      32-bit Locator-Block and 16-bit Locator-Node Function.
      
      [1] - https://datatracker.ietf.org/doc/html/draft-ietf-spring-srv6-srh-compression
      [2] - https://lore.kernel.org/all/20220912171619.16943-1-andrea.mayer@uniroma2.it/
      [3] - https://datatracker.ietf.org/doc/html/rfc8986#name-endx-l3-cross-connectSigned-off-by: default avatarAndrea Mayer <andrea.mayer@uniroma2.it>
      Reviewed-by: default avatarHangbin Liu <liuhangbin@gmail.com>
      Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
      Link: https://lore.kernel.org/r/20230812180926.16689-2-andrea.mayer@uniroma2.itSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      7458575a
  2. 15 Aug, 2023 12 commits
  3. 14 Aug, 2023 27 commits