1 files changed, 40 insertions, 5 deletions

diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 37a1184d789f..b827d21dbe54 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -83,7 +83,6 @@ static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
         peer->fast_recovery = 0;
 
         peer->last_time_heard = jiffies;
-        peer->last_time_used = jiffies;
         peer->last_time_ecne_reduced = jiffies;
 
         peer->init_sent_count = 0;
@@ -564,10 +563,8 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
                  * to be done every RTO interval, we do it every hearbeat
                  * interval.
                  */
-                if (time_after(jiffies, transport->last_time_used +
-                                        transport->rto))
-                        transport->cwnd = max(transport->cwnd/2,
-                                                 4*transport->asoc->pathmtu);
+                transport->cwnd = max(transport->cwnd/2,
+                                         4*transport->asoc->pathmtu);
                 break;
         }
 
@@ -578,6 +575,43 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
                           transport->cwnd, transport->ssthresh);
 }
 
+/* Apply Max.Burst limit to the congestion window:
+ * sctpimpguide-05 2.14.2
+ * D) When the time comes for the sender to
+ * transmit new DATA chunks, the protocol parameter Max.Burst MUST
+ * first be applied to limit how many new DATA chunks may be sent.
+ * The limit is applied by adjusting cwnd as follows:
+ *      if ((flightsize+ Max.Burst * MTU) < cwnd)
+ *              cwnd = flightsize + Max.Burst * MTU
+ */
+
+void sctp_transport_burst_limited(struct sctp_transport *t)
+{
+        struct sctp_association *asoc = t->asoc;
+        u32 old_cwnd = t->cwnd;
+        u32 max_burst_bytes;
+
+        if (t->burst_limited)
+                return;
+
+        max_burst_bytes = t->flight_size + (asoc->max_burst * asoc->pathmtu);
+        if (max_burst_bytes < old_cwnd) {
+                t->cwnd = max_burst_bytes;
+                t->burst_limited = old_cwnd;
+        }
+}
+
+/* Restore the old cwnd congestion window, after the burst had it's
+ * desired effect.
+ */
+void sctp_transport_burst_reset(struct sctp_transport *t)
+{
+        if (t->burst_limited) {
+                t->cwnd = t->burst_limited;
+                t->burst_limited = 0;
+        }
+}
+
 /* What is the next timeout value for this transport? */
 unsigned long sctp_transport_timeout(struct sctp_transport *t)
 {
@@ -600,6 +634,7 @@ void sctp_transport_reset(struct sctp_transport *t)
          * (see Section 6.2.1)
          */
         t->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
+        t->burst_limited = 0;
         t->ssthresh = asoc->peer.i.a_rwnd;
         t->rto = asoc->rto_initial;
         t->rtt = 0;