@@ -1395,35 +1395,44 @@ static inline bool sctp_peer_needs_update(struct sctp_association *asoc)
13951395 return false;
13961396}
13971397
1398- /* Update asoc's rwnd for the approximated state in the buffer,
1399- * and check whether SACK needs to be sent.
1400- */
1401- void sctp_assoc_rwnd_update (struct sctp_association * asoc , bool update_peer )
1398+ /* Increase asoc's rwnd by len and send any window update SACK if needed. */
1399+ void sctp_assoc_rwnd_increase (struct sctp_association * asoc , unsigned int len )
14021400{
1403- int rx_count ;
14041401 struct sctp_chunk * sack ;
14051402 struct timer_list * timer ;
14061403
1407- if (asoc -> ep -> rcvbuf_policy )
1408- rx_count = atomic_read (& asoc -> rmem_alloc );
1409- else
1410- rx_count = atomic_read (& asoc -> base .sk -> sk_rmem_alloc );
1404+ if (asoc -> rwnd_over ) {
1405+ if (asoc -> rwnd_over >= len ) {
1406+ asoc -> rwnd_over -= len ;
1407+ } else {
1408+ asoc -> rwnd += (len - asoc -> rwnd_over );
1409+ asoc -> rwnd_over = 0 ;
1410+ }
1411+ } else {
1412+ asoc -> rwnd += len ;
1413+ }
14111414
1412- if ((asoc -> base .sk -> sk_rcvbuf - rx_count ) > 0 )
1413- asoc -> rwnd = (asoc -> base .sk -> sk_rcvbuf - rx_count ) >> 1 ;
1414- else
1415- asoc -> rwnd = 0 ;
1415+ /* If we had window pressure, start recovering it
1416+ * once our rwnd had reached the accumulated pressure
1417+ * threshold. The idea is to recover slowly, but up
1418+ * to the initial advertised window.
1419+ */
1420+ if (asoc -> rwnd_press && asoc -> rwnd >= asoc -> rwnd_press ) {
1421+ int change = min (asoc -> pathmtu , asoc -> rwnd_press );
1422+ asoc -> rwnd += change ;
1423+ asoc -> rwnd_press -= change ;
1424+ }
14161425
1417- pr_debug ("%s: asoc:%p rwnd=% u, rx_count=%d, sk_rcvbuf=%d \n" ,
1418- __func__ , asoc , asoc -> rwnd , rx_count ,
1419- asoc -> base . sk -> sk_rcvbuf );
1426+ pr_debug ("%s: asoc:%p rwnd increased by %d to (% u, %u) - %u \n" ,
1427+ __func__ , asoc , len , asoc -> rwnd , asoc -> rwnd_over ,
1428+ asoc -> a_rwnd );
14201429
14211430 /* Send a window update SACK if the rwnd has increased by at least the
14221431 * minimum of the association's PMTU and half of the receive buffer.
14231432 * The algorithm used is similar to the one described in
14241433 * Section 4.2.3.3 of RFC 1122.
14251434 */
1426- if (update_peer && sctp_peer_needs_update (asoc )) {
1435+ if (sctp_peer_needs_update (asoc )) {
14271436 asoc -> a_rwnd = asoc -> rwnd ;
14281437
14291438 pr_debug ("%s: sending window update SACK- asoc:%p rwnd:%u "
@@ -1445,6 +1454,45 @@ void sctp_assoc_rwnd_update(struct sctp_association *asoc, bool update_peer)
14451454 }
14461455}
14471456
1457+ /* Decrease asoc's rwnd by len. */
1458+ void sctp_assoc_rwnd_decrease (struct sctp_association * asoc , unsigned int len )
1459+ {
1460+ int rx_count ;
1461+ int over = 0 ;
1462+
1463+ if (unlikely (!asoc -> rwnd || asoc -> rwnd_over ))
1464+ pr_debug ("%s: association:%p has asoc->rwnd:%u, "
1465+ "asoc->rwnd_over:%u!\n" , __func__ , asoc ,
1466+ asoc -> rwnd , asoc -> rwnd_over );
1467+
1468+ if (asoc -> ep -> rcvbuf_policy )
1469+ rx_count = atomic_read (& asoc -> rmem_alloc );
1470+ else
1471+ rx_count = atomic_read (& asoc -> base .sk -> sk_rmem_alloc );
1472+
1473+ /* If we've reached or overflowed our receive buffer, announce
1474+ * a 0 rwnd if rwnd would still be positive. Store the
1475+ * the potential pressure overflow so that the window can be restored
1476+ * back to original value.
1477+ */
1478+ if (rx_count >= asoc -> base .sk -> sk_rcvbuf )
1479+ over = 1 ;
1480+
1481+ if (asoc -> rwnd >= len ) {
1482+ asoc -> rwnd -= len ;
1483+ if (over ) {
1484+ asoc -> rwnd_press += asoc -> rwnd ;
1485+ asoc -> rwnd = 0 ;
1486+ }
1487+ } else {
1488+ asoc -> rwnd_over = len - asoc -> rwnd ;
1489+ asoc -> rwnd = 0 ;
1490+ }
1491+
1492+ pr_debug ("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n" ,
1493+ __func__ , asoc , len , asoc -> rwnd , asoc -> rwnd_over ,
1494+ asoc -> rwnd_press );
1495+ }
14481496
14491497/* Build the bind address list for the association based on info from the
14501498 * local endpoint and the remote peer.
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