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-rw-r--r--net/sctp/transport.c50
1 files changed, 35 insertions, 15 deletions
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index f4938f6c5abe..3f34f61221ec 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -79,6 +79,7 @@ static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
peer->rttvar = 0;
peer->srtt = 0;
peer->rto_pending = 0;
+ peer->fast_recovery = 0;
peer->last_time_heard = jiffies;
peer->last_time_used = jiffies;
@@ -190,7 +191,7 @@ static void sctp_transport_destroy(struct sctp_transport *transport)
/* Start T3_rtx timer if it is not already running and update the heartbeat
* timer. This routine is called every time a DATA chunk is sent.
*/
-void sctp_transport_reset_timers(struct sctp_transport *transport)
+void sctp_transport_reset_timers(struct sctp_transport *transport, int force)
{
/* RFC 2960 6.3.2 Retransmission Timer Rules
*
@@ -200,7 +201,7 @@ void sctp_transport_reset_timers(struct sctp_transport *transport)
* address.
*/
- if (!timer_pending(&transport->T3_rtx_timer))
+ if (force || !timer_pending(&transport->T3_rtx_timer))
if (!mod_timer(&transport->T3_rtx_timer,
jiffies + transport->rto))
sctp_transport_hold(transport);
@@ -291,7 +292,7 @@ void sctp_transport_route(struct sctp_transport *transport,
if (saddr)
memcpy(&transport->saddr, saddr, sizeof(union sctp_addr));
else
- af->get_saddr(asoc, dst, daddr, &transport->saddr);
+ af->get_saddr(opt, asoc, dst, daddr, &transport->saddr);
transport->dst = dst;
if ((transport->param_flags & SPP_PMTUD_DISABLE) && transport->pathmtu) {
@@ -403,11 +404,16 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport,
cwnd = transport->cwnd;
flight_size = transport->flight_size;
+ /* See if we need to exit Fast Recovery first */
+ if (transport->fast_recovery &&
+ TSN_lte(transport->fast_recovery_exit, sack_ctsn))
+ transport->fast_recovery = 0;
+
/* The appropriate cwnd increase algorithm is performed if, and only
- * if the cumulative TSN has advanced and the congestion window is
+ * if the cumulative TSN whould advanced and the congestion window is
* being fully utilized.
*/
- if ((transport->asoc->ctsn_ack_point >= sack_ctsn) ||
+ if (TSN_lte(sack_ctsn, transport->asoc->ctsn_ack_point) ||
(flight_size < cwnd))
return;
@@ -416,17 +422,23 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport,
pmtu = transport->asoc->pathmtu;
if (cwnd <= ssthresh) {
- /* RFC 2960 7.2.1, sctpimpguide-05 2.14.2 When cwnd is less
- * than or equal to ssthresh an SCTP endpoint MUST use the
- * slow start algorithm to increase cwnd only if the current
- * congestion window is being fully utilized and an incoming
- * SACK advances the Cumulative TSN Ack Point. Only when these
- * two conditions are met can the cwnd be increased otherwise
- * the cwnd MUST not be increased. If these conditions are met
- * then cwnd MUST be increased by at most the lesser of
- * 1) the total size of the previously outstanding DATA
- * chunk(s) acknowledged, and 2) the destination's path MTU.
+ /* RFC 4960 7.2.1
+ * o When cwnd is less than or equal to ssthresh, an SCTP
+ * endpoint MUST use the slow-start algorithm to increase
+ * cwnd only if the current congestion window is being fully
+ * utilized, an incoming SACK advances the Cumulative TSN
+ * Ack Point, and the data sender is not in Fast Recovery.
+ * Only when these three conditions are met can the cwnd be
+ * increased; otherwise, the cwnd MUST not be increased.
+ * If these conditions are met, then cwnd MUST be increased
+ * by, at most, the lesser of 1) the total size of the
+ * previously outstanding DATA chunk(s) acknowledged, and
+ * 2) the destination's path MTU. This upper bound protects
+ * against the ACK-Splitting attack outlined in [SAVAGE99].
*/
+ if (transport->fast_recovery)
+ return;
+
if (bytes_acked > pmtu)
cwnd += pmtu;
else
@@ -502,6 +514,13 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
* cwnd = ssthresh
* partial_bytes_acked = 0
*/
+ if (transport->fast_recovery)
+ return;
+
+ /* Mark Fast recovery */
+ transport->fast_recovery = 1;
+ transport->fast_recovery_exit = transport->asoc->next_tsn - 1;
+
transport->ssthresh = max(transport->cwnd/2,
4*transport->asoc->pathmtu);
transport->cwnd = transport->ssthresh;
@@ -586,6 +605,7 @@ void sctp_transport_reset(struct sctp_transport *t)
t->flight_size = 0;
t->error_count = 0;
t->rto_pending = 0;
+ t->fast_recovery = 0;
/* Initialize the state information for SFR-CACC */
t->cacc.changeover_active = 0;
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