From f4ff7acf30f0973421327d553cb50957de02ecda Mon Sep 17 00:00:00 2001 From: lucien Date: Sat, 5 Dec 2015 15:35:36 +0800 Subject: [PATCH] sctp: start t5 timer only when peer rwnd is 0 and local state is SHUTDOWN_PENDING when A sends a data to B, then A close() and enter into SHUTDOWN_PENDING state, if B neither claim his rwnd is 0 nor send SACK for this data, A will keep retransmitting this data until t5 timeout, Max.Retrans times can't work anymore, which is bad. if B's rwnd is not 0, it should send abort after Max.Retrans times, only when B's rwnd == 0 and A's retransmitting beyonds Max.Retrans times, A will start t5 timer, which is also commit 47a1ea9a6800 ("sctp: Enforce retransmission limit during shutdown") means, but it lacks the condition peer rwnd == 0. so fix it by adding a bit (zero_window_announced) in peer to record if the last rwnd is 0. If it was, zero_window_announced will be set. and use this bit to decide if start t5 timer when local.state is SHUTDOWN_PENDING. Fixes: commit 47a1ea9a6800 ("sctp: Enforce retransmission limit during shutdown") Signed-off-by: Xin Long Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- include/net/sctp/structs.h | 3 ++- net/sctp/outqueue.c | 1 + net/sctp/sm_statefuns.c | 3 ++- 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index 7bbb71081aeb6..eea9bdeecba27 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -1493,7 +1493,8 @@ struct sctp_association { * : SACK's are not delayed (see Section 6). */ __u8 sack_needed:1, /* Do we need to sack the peer? */ - sack_generation:1; + sack_generation:1, + zero_window_announced:1; __u32 sack_cnt; __u32 adaptation_ind; /* Adaptation Code point. */ diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c index 0b3d8189f140e..c0380cfb16ae4 100644 --- a/net/sctp/outqueue.c +++ b/net/sctp/outqueue.c @@ -1252,6 +1252,7 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) */ sack_a_rwnd = ntohl(sack->a_rwnd); + asoc->peer.zero_window_announced = !sack_a_rwnd; outstanding = q->outstanding_bytes; if (outstanding < sack_a_rwnd) diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 6f46aa16cb769..cd34a4a340657 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -5412,7 +5412,8 @@ sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); if (asoc->overall_error_count >= asoc->max_retrans) { - if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { + if (asoc->peer.zero_window_announced && + asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { /* * We are here likely because the receiver had its rwnd * closed for a while and we have not been able to -- 2.39.5