sctp: Failover transmitted list on transport delete

Add-IP feature allows users to delete an active transport.  If that
transport has chunks in flight, those chunks need to be moved to another
transport or association may get into unrecoverable state.

Reported-by: Rafael Laufer <rlaufer@cisco.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 34 insertions, 13 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index d765fc53e74d..c9f20e28521b 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -406,8 +406,9 @@ void sctp_retransmit_mark(struct sctp_outq *q,
 			 * not be retransmitted
 			 */
 			if (!chunk->tsn_gap_acked) {
-				chunk->transport->flight_size -=
-						sctp_data_size(chunk);
+				if (chunk->transport)
+					chunk->transport->flight_size -=
+							sctp_data_size(chunk);
 				q->outstanding_bytes -= sctp_data_size(chunk);
 				q->asoc->peer.rwnd += (sctp_data_size(chunk) +
 							sizeof(struct sk_buff));
@@ -443,7 +444,8 @@ void sctp_retransmit_mark(struct sctp_outq *q,
 			q->asoc->peer.rwnd += (sctp_data_size(chunk) +
 						sizeof(struct sk_buff));
 			q->outstanding_bytes -= sctp_data_size(chunk);
-			transport->flight_size -= sctp_data_size(chunk);
+			if (chunk->transport)
+				transport->flight_size -= sctp_data_size(chunk);
 
 			/* sctpimpguide-05 Section 2.8.2
 			 * M5) If a T3-rtx timer expires, the
@@ -1310,6 +1312,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 	__u32 rtt;
 	__u8 restart_timer = 0;
 	int bytes_acked = 0;
+	int migrate_bytes = 0;
 
 	/* These state variables are for coherent debug output. --xguo */
 
@@ -1343,8 +1346,9 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 			 * considering it as 'outstanding'.
 			 */
 			if (!tchunk->tsn_gap_acked) {
-				tchunk->transport->flight_size -=
-						sctp_data_size(tchunk);
+				if (tchunk->transport)
+					tchunk->transport->flight_size -=
+							sctp_data_size(tchunk);
 				q->outstanding_bytes -= sctp_data_size(tchunk);
 			}
 			continue;
@@ -1378,6 +1382,20 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 								  rtt);
 				}
 			}
+
+			/* If the chunk hasn't been marked as ACKED,
+			 * mark it and account bytes_acked if the
+			 * chunk had a valid transport (it will not
+			 * have a transport if ASCONF had deleted it
+			 * while DATA was outstanding).
+			 */
+			if (!tchunk->tsn_gap_acked) {
+				tchunk->tsn_gap_acked = 1;
+				bytes_acked += sctp_data_size(tchunk);
+				if (!tchunk->transport)
+					migrate_bytes += sctp_data_size(tchunk);
+			}
+
 			if (TSN_lte(tsn, sack_ctsn)) {
 				/* RFC 2960  6.3.2 Retransmission Timer Rules
 				 *
@@ -1391,8 +1409,6 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 				restart_timer = 1;
 
 				if (!tchunk->tsn_gap_acked) {
-					tchunk->tsn_gap_acked = 1;
-					bytes_acked += sctp_data_size(tchunk);
 					/*
 					 * SFR-CACC algorithm:
 					 * 2) If the SACK contains gap acks
@@ -1432,10 +1448,6 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 				 * older than that newly acknowledged DATA
 				 * chunk, are qualified as 'Stray DATA chunks'.
 				 */
-				if (!tchunk->tsn_gap_acked) {
-					tchunk->tsn_gap_acked = 1;
-					bytes_acked += sctp_data_size(tchunk);
-				}
 				list_add_tail(lchunk, &tlist);
 			}
 
@@ -1491,7 +1503,8 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 						  tsn);
 				tchunk->tsn_gap_acked = 0;
 
-				bytes_acked -= sctp_data_size(tchunk);
+				if (tchunk->transport)
+					bytes_acked -= sctp_data_size(tchunk);
 
 				/* RFC 2960 6.3.2 Retransmission Timer Rules
 				 *
@@ -1561,6 +1574,14 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 #endif /* SCTP_DEBUG */
 	if (transport) {
 		if (bytes_acked) {
+			/* We may have counted DATA that was migrated
+			 * to this transport due to DEL-IP operation.
+			 * Subtract those bytes, since the were never
+			 * send on this transport and shouldn't be
+			 * credited to this transport.
+			 */
+			bytes_acked -= migrate_bytes;
+
 			/* 8.2. When an outstanding TSN is acknowledged,
 			 * the endpoint shall clear the error counter of
 			 * the destination transport address to which the
@@ -1589,7 +1610,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
 			transport->flight_size -= bytes_acked;
 			if (transport->flight_size == 0)
 				transport->partial_bytes_acked = 0;
-			q->outstanding_bytes -= bytes_acked;
+			q->outstanding_bytes -= bytes_acked + migrate_bytes;
 		} else {
 			/* RFC 2960 6.1, sctpimpguide-06 2.15.2
 			 * When a sender is doing zero window probing, it