Commit 8c2f414a authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

net: sctp: confirm route during forward progress

This fix has been proposed originally by Vlad Yasevich. He says:

  When SCTP makes forward progress (receives a SACK that acks new chunks,
  renegs, or answeres 0-window probes) or when HB-ACK arrives, mark
  the route as confirmed so we don't unnecessarily send NUD probes.

Having a simple SCTP client/server that exchange data chunks every 1sec,
without this patch ARP requests are sent periodically every 40-60sec.
With this fix applied, an ARP request is only done once right at the
"session" beginning. Also, when clearing the related ARP cache entry
manually during the session, a new request is correctly done. I have
only "backported" this to net-next and tested that it works, so full
credit goes to Vlad.
Signed-off-by: default avatarVlad Yasevich <>
Signed-off-by: default avatarDaniel Borkmann <>
Acked-by: default avatarNeil Horman <>
Signed-off-by: default avatarDavid S. Miller <>
parent e1d6fbc3
......@@ -1334,6 +1334,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
__u8 restart_timer = 0;
int bytes_acked = 0;
int migrate_bytes = 0;
bool forward_progress = false;
sack_ctsn = ntohl(sack->cum_tsn_ack);
......@@ -1400,6 +1401,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
bytes_acked += sctp_data_size(tchunk);
if (!tchunk->transport)
migrate_bytes += sctp_data_size(tchunk);
forward_progress = true;
if (TSN_lte(tsn, sack_ctsn)) {
......@@ -1413,6 +1415,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
* current RTO.
restart_timer = 1;
forward_progress = true;
if (!tchunk->tsn_gap_acked) {
......@@ -1503,6 +1506,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
transport->error_count = 0;
transport->asoc->overall_error_count = 0;
forward_progress = true;
* While in SHUTDOWN PENDING, we may have started
......@@ -1576,6 +1580,11 @@ static void sctp_check_transmitted(struct sctp_outq *q,
jiffies + transport->rto))
if (forward_progress) {
if (transport->dst)
list_splice(&tlist, transmitted_queue);
......@@ -730,6 +730,12 @@ static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
/* HB-ACK was received for a the proper HB. Consider this
* forward progress.
if (t->dst)
/* The receiver of the HEARTBEAT ACK should also perform an
* RTT measurement for that destination transport address
* using the time value carried in the HEARTBEAT ACK chunk.
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