• Marcelo Ricardo Leitner's avatar
    sctp: Add GSO support · 90017acc
    Marcelo Ricardo Leitner authored
    SCTP has this pecualiarity that its packets cannot be just segmented to
    (P)MTU. Its chunks must be contained in IP segments, padding respected.
    So we can't just generate a big skb, set gso_size to the fragmentation
    point and deliver it to IP layer.
    
    This patch takes a different approach. SCTP will now build a skb as it
    would be if it was received using GRO. That is, there will be a cover
    skb with protocol headers and children ones containing the actual
    segments, already segmented to a way that respects SCTP RFCs.
    
    With that, we can tell skb_segment() to just split based on frag_list,
    trusting its sizes are already in accordance.
    
    This way SCTP can benefit from GSO and instead of passing several
    packets through the stack, it can pass a single large packet.
    
    v2:
    - Added support for receiving GSO frames, as requested by Dave Miller.
    - Clear skb->cb if packet is GSO (otherwise it's not used by SCTP)
    - Added heuristics similar to what we have in TCP for not generating
      single GSO packets that fills cwnd.
    v3:
    - consider sctphdr size in skb_gso_transport_seglen()
    - rebased due to 5c7cdf33 ("gso: Remove arbitrary checks for
      unsupported GSO")
    Signed-off-by: 's avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
    Tested-by: 's avatarXin Long <lucien.xin@gmail.com>
    Signed-off-by: 's avatarDavid S. Miller <davem@davemloft.net>
    90017acc
netdev_features.h 8.4 KB