sctp: fast recovery algorithm is per association.

SCTP fast recovery algorithm really applies per association
and impacts all transports.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

2 files changed, 23 insertions, 21 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 9072dd67d8ad..d463296d9f79 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -895,9 +895,6 @@ struct sctp_transport {
                  */
                 hb_sent:1,
 
-                /* Flag to track the current fast recovery state */
-                fast_recovery:1,
-
                 /* Is the Path MTU update pending on this tranport */
                 pmtu_pending:1,
 
@@ -952,9 +949,6 @@ struct sctp_transport {
 
         __u32 burst_limited;    /* Holds old cwnd when max.burst is applied */
 
-        /* TSN marking the fast recovery exit point */
-        __u32 fast_recovery_exit;
-
         /* Destination */
         struct dst_entry *dst;
         /* Source address. */
@@ -1723,6 +1717,12 @@ struct sctp_association {
         /* Highest TSN that is acknowledged by incoming SACKs. */
         __u32 highest_sacked;
 
+        /* TSN marking the fast recovery exit point */
+        __u32 fast_recovery_exit;
+
+        /* Flag to track the current fast recovery state */
+        __u8 fast_recovery;
+
         /* The number of unacknowledged data chunks.  Reported through
          * the SCTP_STATUS sockopt.
          */
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 854228bf3f34..fccf4947aff1 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -378,15 +378,16 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
 void sctp_transport_raise_cwnd(struct sctp_transport *transport,
                                __u32 sack_ctsn, __u32 bytes_acked)
 {
+        struct sctp_association *asoc = transport->asoc;
         __u32 cwnd, ssthresh, flight_size, pba, pmtu;
 
         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;
+        if (asoc->fast_recovery &&
+            TSN_lte(asoc->fast_recovery_exit, sack_ctsn))
+                asoc->fast_recovery = 0;
 
         /* The appropriate cwnd increase algorithm is performed if, and only
          * if the cumulative TSN whould advanced and the congestion window is
@@ -415,7 +416,7 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport,
                  *    2) the destination's path MTU.  This upper bound protects
                  *    against the ACK-Splitting attack outlined in [SAVAGE99].
                  */
-                if (transport->fast_recovery)
+                if (asoc->fast_recovery)
                         return;
 
                 if (bytes_acked > pmtu)
@@ -466,6 +467,8 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport,
 void sctp_transport_lower_cwnd(struct sctp_transport *transport,
                                sctp_lower_cwnd_t reason)
 {
+        struct sctp_association *asoc = transport->asoc;
+
         switch (reason) {
         case SCTP_LOWER_CWND_T3_RTX:
                 /* RFC 2960 Section 7.2.3, sctpimpguide
@@ -476,11 +479,11 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
                  *      partial_bytes_acked = 0
                  */
                 transport->ssthresh = max(transport->cwnd/2,
-                                          4*transport->asoc->pathmtu);
-                transport->cwnd = transport->asoc->pathmtu;
+                                          4*asoc->pathmtu);
+                transport->cwnd = asoc->pathmtu;
 
-                /* T3-rtx also clears fast recovery on the transport */
-                transport->fast_recovery = 0;
+                /* T3-rtx also clears fast recovery */
+                asoc->fast_recovery = 0;
                 break;
 
         case SCTP_LOWER_CWND_FAST_RTX:
@@ -496,15 +499,15 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
                  *      cwnd = ssthresh
                  *      partial_bytes_acked = 0
                  */
-                if (transport->fast_recovery)
+                if (asoc->fast_recovery)
                         return;
 
                 /* Mark Fast recovery */
-                transport->fast_recovery = 1;
-                transport->fast_recovery_exit = transport->asoc->next_tsn - 1;
+                asoc->fast_recovery = 1;
+                asoc->fast_recovery_exit = asoc->next_tsn - 1;
 
                 transport->ssthresh = max(transport->cwnd/2,
-                                          4*transport->asoc->pathmtu);
+                                          4*asoc->pathmtu);
                 transport->cwnd = transport->ssthresh;
                 break;
 
@@ -524,7 +527,7 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
                 if (time_after(jiffies, transport->last_time_ecne_reduced +
                                         transport->rtt)) {
                         transport->ssthresh = max(transport->cwnd/2,
-                                                  4*transport->asoc->pathmtu);
+                                                  4*asoc->pathmtu);
                         transport->cwnd = transport->ssthresh;
                         transport->last_time_ecne_reduced = jiffies;
                 }
@@ -540,7 +543,7 @@ void sctp_transport_lower_cwnd(struct sctp_transport *transport,
                  * interval.
                  */
                 transport->cwnd = max(transport->cwnd/2,
-                                         4*transport->asoc->pathmtu);
+                                         4*asoc->pathmtu);
                 break;
         }
 
@@ -625,7 +628,6 @@ void sctp_transport_reset(struct sctp_transport *t)
         t->error_count = 0;
         t->rto_pending = 0;
         t->hb_sent = 0;
-        t->fast_recovery = 0;
 
         /* Initialize the state information for SFR-CACC */
         t->cacc.changeover_active = 0;