The function sctp_sf_eat_sack_6_2 now performs the Verification Tag validation, Chunk length validation, Bogu check, and also the detection of out-of-order SACK based on the RFC2960 Section 6.2 at the beginning, and finally performs the further processing of SACK. The trace_sctp_probe now triggered before the above necessary validation and check. this patch is to do the trace_sctp_probe after the chunk sanity tests, but keep doing trace if the SACK received is out of order, for the out-of-order SACK is valuable to congestion control debugging. v1->v2: - keep doing SCTP trace if the SACK is out of order as Marcelo's suggestion. Signed-off-by: Kevin Kou <qdkevin.kou@xxxxxxxxx> --- net/sctp/sm_statefuns.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index b4a54df..d302a78 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -3298,6 +3298,15 @@ enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, chunk->subh.sack_hdr = sackh; ctsn = ntohl(sackh->cum_tsn_ack); + /* If Cumulative TSN Ack beyond the max tsn currently + * send, terminating the association and respond to the + * sender with an ABORT. + */ + if (TSN_lte(asoc->next_tsn, ctsn)) + return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); + + trace_sctp_probe(ep, asoc, chunk); + /* i) If Cumulative TSN Ack is less than the Cumulative TSN * Ack Point, then drop the SACK. Since Cumulative TSN * Ack is monotonically increasing, a SACK whose @@ -3311,15 +3320,6 @@ enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, return SCTP_DISPOSITION_DISCARD; } - /* If Cumulative TSN Ack beyond the max tsn currently - * send, terminating the association and respond to the - * sender with an ABORT. - */ - if (!TSN_lt(ctsn, asoc->next_tsn)) - return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); - - trace_sctp_probe(ep, asoc, chunk); - /* Return this SACK for further processing. */ sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); -- 1.8.3.1
