SCTP: Fix difference cases of retransmit.

Commit d0ce92910bc04e107b2f3f2048f07e94f570035d broke several retransmit
cases including fast retransmit.  The reason is that we should
only delay by rto while doing retranmists as a result of a timeout.
Retransmit as a result of path mtu discover, fast retransmit, or
other evernts that should trigger immidiate retransmissions got broken.

Also, since rto is doubled prior to marking of packets elegable for
retransmission, we never marked correct chunks anyway.

The fix is provide a reason for a given retransmission so that we
can mark chunks appropriately and to save the old rto value to do
comparisons against.

All regressions tests passed with this code.

Spotted by Wei Yongjun <yjwei@cn.fujitsu.com>

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

4 files changed, 6 insertions, 2 deletions

diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
index b8733364557f..c1f797673571 100644
--- a/include/net/sctp/command.h
+++ b/include/net/sctp/command.h
@@ -103,6 +103,7 @@ typedef enum {
         SCTP_CMD_ASSOC_CHANGE,   /* generate and send assoc_change event */
         SCTP_CMD_ADAPTATION_IND, /* generate and send adaptation event */
         SCTP_CMD_ASSOC_SHKEY,    /* generate the association shared keys */
+        SCTP_CMD_T1_RETRAN,      /* Mark for retransmission after T1 timeout  */
         SCTP_CMD_LAST
 } sctp_verb_t;
 
diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
index da8354e8e33c..73fbdf6a24f8 100644
--- a/include/net/sctp/constants.h
+++ b/include/net/sctp/constants.h
@@ -407,6 +407,7 @@ typedef enum {
         SCTP_RTXR_T3_RTX,
         SCTP_RTXR_FAST_RTX,
         SCTP_RTXR_PMTUD,
+        SCTP_RTXR_T1_RTX,
 } sctp_retransmit_reason_t;
 
 /* Reasons to lower cwnd. */
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 93eb708609e7..70827305f501 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -267,6 +267,7 @@ enum
         SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
         SCTP_MIB_DELAY_SACK_EXPIREDS,
         SCTP_MIB_AUTOCLOSE_EXPIREDS,
+        SCTP_MIB_T1_RETRANSMITS,
         SCTP_MIB_T3_RETRANSMITS,
         SCTP_MIB_PMTUD_RETRANSMITS,
         SCTP_MIB_FAST_RETRANSMITS,
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index ef892e00c833..482c2aab3d67 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -873,10 +873,11 @@ struct sctp_transport {
          * address list derived from the INIT or INIT ACK chunk, a
          * number of data elements needs to be maintained including:
          */
-        __u32 rtt;              /* This is the most recent RTT.  */
-
         /* RTO         : The current retransmission timeout value.  */
         unsigned long rto;
+        unsigned long last_rto;
+
+        __u32 rtt;              /* This is the most recent RTT.  */
 
         /* RTTVAR      : The current RTT variation.  */
         __u32 rttvar;