From 4ebef63e925e37f5de2f9da8fc86a545e4e0b945 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 10 Mar 2016 15:31:57 +0800 Subject: [PATCH] sctp: fix the transports round robin issue when init is retransmitted commit 39d2adebf137de5f900843f69f5e500932e31047 upstream. prior to this patch, at the beginning if we have two paths in one assoc, they may have the same params other than the last_time_heard, it will try the paths like this: 1st cycle try trans1 fail. then trans2 is selected.(cause it's last_time_heard is after trans1). 2nd cycle: try trans2 fail then trans2 is selected.(cause it's last_time_heard is after trans1). 3rd cycle: try trans2 fail then trans2 is selected.(cause it's last_time_heard is after trans1). .... trans1 will never have change to be selected, which is not what we expect. we should keeping round robin all the paths if they are just added at the beginning. So at first every tranport's last_time_heard should be initialized 0, so that we ensure they have the same value at the beginning, only by this, all the transports could get equal chance to be selected. Then for sctp_trans_elect_best, it should return the trans_next one when *trans == *trans_next, so that we can try next if it fails, but now it always return trans. so we can fix it by exchanging these two params when we calls sctp_trans_elect_tie(). Fixes: 4c47af4d5eb2 ('net: sctp: rework multihoming retransmission path selection to rfc4960') Signed-off-by: Xin Long Acked-by: Daniel Borkmann Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sctp/associola.c | 2 +- net/sctp/transport.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sctp/associola.c b/net/sctp/associola.c index f085b01b6603..f24d31f12cb4 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -1290,7 +1290,7 @@ static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr, if (score_curr > score_best) return curr; else if (score_curr == score_best) - return sctp_trans_elect_tie(curr, best); + return sctp_trans_elect_tie(best, curr); else return best; } diff --git a/net/sctp/transport.c b/net/sctp/transport.c index aab9e3f29755..fbbe268e34e7 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -72,7 +72,7 @@ static struct sctp_transport *sctp_transport_init(struct net *net, */ peer->rto = msecs_to_jiffies(net->sctp.rto_initial); - peer->last_time_heard = ktime_get(); + peer->last_time_heard = ktime_set(0, 0); peer->last_time_ecne_reduced = jiffies; peer->param_flags = SPP_HB_DISABLE |