• Ahmed Abdelsalam's avatar
    seg6: fix SRH processing to comply with RFC8754 · 0cb7498f
    Ahmed Abdelsalam authored
    The Segment Routing Header (SRH) which defines the SRv6 dataplane is defined
    in RFC8754.
    
    RFC8754 (section 4.1) defines the SR source node behavior which encapsulates
    packets into an outer IPv6 header and SRH. The SR source node encodes the
    full list of Segments that defines the packet path in the SRH. Then, the
    first segment from list of Segments is copied into the Destination address
    of the outer IPv6 header and the packet is sent to the first hop in its path
    towards the destination.
    
    If the Segment list has only one segment, the SR source node can omit the SRH
    as he only segment is added in the destination address.
    
    RFC8754 (section 4.1.1) defines the Reduced SRH, when a source does not
    require the entire SID list to be preserved in the SRH. A reduced SRH does
    not contain the first segment of the related SR Policy (the first segment is
    the one already in the DA of the IPv6 header), and the Last Entry field is
    set to n-2, where n is the number of elements in the SR Policy.
    
    RFC8754 (section 4.3.1.1) defines the SRH processing and the logic to
    validate the SRH (S09, S10, S11) which works for both reduced and
    non-reduced behaviors.
    
    This patch updates seg6_validate_srh() to validate the SRH as per RFC8754.
    Signed-off-by: default avatarAhmed Abdelsalam <ahabdels@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    0cb7498f
seg6.c 9.89 KB