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>

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 9072dd6..d463296 100644 (file)
--- 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 854228b..fccf494 100644 (file)
--- 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;