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authorMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>2016-06-02 15:05:43 -0300
committerDavid S. Miller <davem@davemloft.net>2016-06-03 19:37:21 -0400
commit90017accff61ae89283ad9a51f9ac46ca01633fb (patch)
treec62d8801baf03dfd048848e6b6ea325d94c481a6 /net/sctp/input.c
parent3acb50c18d8d6650f10919464ade4dcdaf41d62f (diff)
sctp: Add GSO support
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 5c7cdf339af5 ("gso: Remove arbitrary checks for unsupported GSO") Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Tested-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp/input.c')
-rw-r--r--net/sctp/input.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 5cff2546c3dd..6f8e676d285e 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -139,7 +139,9 @@ int sctp_rcv(struct sk_buff *skb)
skb->csum_valid = 0; /* Previous value not applicable */
if (skb_csum_unnecessary(skb))
__skb_decr_checksum_unnecessary(skb);
- else if (!sctp_checksum_disable && sctp_rcv_checksum(net, skb) < 0)
+ else if (!sctp_checksum_disable &&
+ !(skb_shinfo(skb)->gso_type & SKB_GSO_SCTP) &&
+ sctp_rcv_checksum(net, skb) < 0)
goto discard_it;
skb->csum_valid = 1;
@@ -1175,6 +1177,14 @@ static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
{
sctp_chunkhdr_t *ch;
+ /* We do not allow GSO frames here as we need to linearize and
+ * then cannot guarantee frame boundaries. This shouldn't be an
+ * issue as packets hitting this are mostly INIT or INIT-ACK and
+ * those cannot be on GSO-style anyway.
+ */
+ if ((skb_shinfo(skb)->gso_type & SKB_GSO_SCTP) == SKB_GSO_SCTP)
+ return NULL;
+
if (skb_linearize(skb))
return NULL;