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Diffstat (limited to 'net/sctp/associola.c')
-rw-r--r--net/sctp/associola.c82
1 files changed, 65 insertions, 17 deletions
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 4f6d6f9d1274..39579c3e0d14 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -1395,35 +1395,44 @@ static inline bool sctp_peer_needs_update(struct sctp_association *asoc)
return false;
}
-/* Update asoc's rwnd for the approximated state in the buffer,
- * and check whether SACK needs to be sent.
- */
-void sctp_assoc_rwnd_update(struct sctp_association *asoc, bool update_peer)
+/* Increase asoc's rwnd by len and send any window update SACK if needed. */
+void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len)
{
- int rx_count;
struct sctp_chunk *sack;
struct timer_list *timer;
- if (asoc->ep->rcvbuf_policy)
- rx_count = atomic_read(&asoc->rmem_alloc);
- else
- rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
+ if (asoc->rwnd_over) {
+ if (asoc->rwnd_over >= len) {
+ asoc->rwnd_over -= len;
+ } else {
+ asoc->rwnd += (len - asoc->rwnd_over);
+ asoc->rwnd_over = 0;
+ }
+ } else {
+ asoc->rwnd += len;
+ }
- if ((asoc->base.sk->sk_rcvbuf - rx_count) > 0)
- asoc->rwnd = (asoc->base.sk->sk_rcvbuf - rx_count) >> 1;
- else
- asoc->rwnd = 0;
+ /* If we had window pressure, start recovering it
+ * once our rwnd had reached the accumulated pressure
+ * threshold. The idea is to recover slowly, but up
+ * to the initial advertised window.
+ */
+ if (asoc->rwnd_press && asoc->rwnd >= asoc->rwnd_press) {
+ int change = min(asoc->pathmtu, asoc->rwnd_press);
+ asoc->rwnd += change;
+ asoc->rwnd_press -= change;
+ }
- pr_debug("%s: asoc:%p rwnd=%u, rx_count=%d, sk_rcvbuf=%d\n",
- __func__, asoc, asoc->rwnd, rx_count,
- asoc->base.sk->sk_rcvbuf);
+ pr_debug("%s: asoc:%p rwnd increased by %d to (%u, %u) - %u\n",
+ __func__, asoc, len, asoc->rwnd, asoc->rwnd_over,
+ asoc->a_rwnd);
/* Send a window update SACK if the rwnd has increased by at least the
* minimum of the association's PMTU and half of the receive buffer.
* The algorithm used is similar to the one described in
* Section 4.2.3.3 of RFC 1122.
*/
- if (update_peer && sctp_peer_needs_update(asoc)) {
+ if (sctp_peer_needs_update(asoc)) {
asoc->a_rwnd = asoc->rwnd;
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)
}
}
+/* Decrease asoc's rwnd by len. */
+void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
+{
+ int rx_count;
+ int over = 0;
+
+ if (unlikely(!asoc->rwnd || asoc->rwnd_over))
+ pr_debug("%s: association:%p has asoc->rwnd:%u, "
+ "asoc->rwnd_over:%u!\n", __func__, asoc,
+ asoc->rwnd, asoc->rwnd_over);
+
+ if (asoc->ep->rcvbuf_policy)
+ rx_count = atomic_read(&asoc->rmem_alloc);
+ else
+ rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
+
+ /* If we've reached or overflowed our receive buffer, announce
+ * a 0 rwnd if rwnd would still be positive. Store the
+ * the potential pressure overflow so that the window can be restored
+ * back to original value.
+ */
+ if (rx_count >= asoc->base.sk->sk_rcvbuf)
+ over = 1;
+
+ if (asoc->rwnd >= len) {
+ asoc->rwnd -= len;
+ if (over) {
+ asoc->rwnd_press += asoc->rwnd;
+ asoc->rwnd = 0;
+ }
+ } else {
+ asoc->rwnd_over = len - asoc->rwnd;
+ asoc->rwnd = 0;
+ }
+
+ pr_debug("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n",
+ __func__, asoc, len, asoc->rwnd, asoc->rwnd_over,
+ asoc->rwnd_press);
+}
/* Build the bind address list for the association based on info from the
* local endpoint and the remote peer.