/* Only real associations count against the endpoint, so
* don't bother for if this is a temporary association.
*/
- if (!asoc->temp) {
+ if (!list_empty(&asoc->asocs)) {
list_del(&asoc->asocs);
/* Decrement the backlog value for a TCP-style listening
asoc->c = new->c;
asoc->peer.rwnd = new->peer.rwnd;
asoc->peer.sack_needed = new->peer.sack_needed;
+ asoc->peer.auth_capable = new->peer.auth_capable;
asoc->peer.i = new->peer.i;
sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
asoc->peer.i.initial_tsn, GFP_ATOMIC);
}
/* Update the retran path for sending a retransmitted packet.
- * Round-robin through the active transports, else round-robin
- * through the inactive transports as this is the next best thing
- * we can try.
+ * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints:
+ *
+ * When there is outbound data to send and the primary path
+ * becomes inactive (e.g., due to failures), or where the
+ * SCTP user explicitly requests to send data to an
+ * inactive destination transport address, before reporting
+ * an error to its ULP, the SCTP endpoint should try to send
+ * the data to an alternate active destination transport
+ * address if one exists.
+ *
+ * When retransmitting data that timed out, if the endpoint
+ * is multihomed, it should consider each source-destination
+ * address pair in its retransmission selection policy.
+ * When retransmitting timed-out data, the endpoint should
+ * attempt to pick the most divergent source-destination
+ * pair from the original source-destination pair to which
+ * the packet was transmitted.
+ *
+ * Note: Rules for picking the most divergent source-destination
+ * pair are an implementation decision and are not specified
+ * within this document.
+ *
+ * Our basic strategy is to round-robin transports in priorities
+ * according to sctp_state_prio_map[] e.g., if no such
+ * transport with state SCTP_ACTIVE exists, round-robin through
+ * SCTP_UNKNOWN, etc. You get the picture.
*/
-void sctp_assoc_update_retran_path(struct sctp_association *asoc)
+static const u8 sctp_trans_state_to_prio_map[] = {
+ [SCTP_ACTIVE] = 3, /* best case */
+ [SCTP_UNKNOWN] = 2,
+ [SCTP_PF] = 1,
+ [SCTP_INACTIVE] = 0, /* worst case */
+};
+
+static u8 sctp_trans_score(const struct sctp_transport *trans)
{
- struct sctp_transport *t, *next;
- struct list_head *head = &asoc->peer.transport_addr_list;
- struct list_head *pos;
+ return sctp_trans_state_to_prio_map[trans->state];
+}
- if (asoc->peer.transport_count == 1)
- return;
+static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr,
+ struct sctp_transport *best)
+{
+ if (best == NULL)
+ return curr;
- /* Find the next transport in a round-robin fashion. */
- t = asoc->peer.retran_path;
- pos = &t->transports;
- next = NULL;
+ return sctp_trans_score(curr) > sctp_trans_score(best) ? curr : best;
+}
- while (1) {
- /* Skip the head. */
- if (pos->next == head)
- pos = head->next;
- else
- pos = pos->next;
+void sctp_assoc_update_retran_path(struct sctp_association *asoc)
+{
+ struct sctp_transport *trans = asoc->peer.retran_path;
+ struct sctp_transport *trans_next = NULL;
- t = list_entry(pos, struct sctp_transport, transports);
+ /* We're done as we only have the one and only path. */
+ if (asoc->peer.transport_count == 1)
+ return;
+ /* If active_path and retran_path are the same and active,
+ * then this is the only active path. Use it.
+ */
+ if (asoc->peer.active_path == asoc->peer.retran_path &&
+ asoc->peer.active_path->state == SCTP_ACTIVE)
+ return;
- /* We have exhausted the list, but didn't find any
- * other active transports. If so, use the next
- * transport.
- */
- if (t == asoc->peer.retran_path) {
- t = next;
+ /* Iterate from retran_path's successor back to retran_path. */
+ for (trans = list_next_entry(trans, transports); 1;
+ trans = list_next_entry(trans, transports)) {
+ /* Manually skip the head element. */
+ if (&trans->transports == &asoc->peer.transport_addr_list)
+ continue;
+ if (trans->state == SCTP_UNCONFIRMED)
+ continue;
+ trans_next = sctp_trans_elect_best(trans, trans_next);
+ /* Active is good enough for immediate return. */
+ if (trans_next->state == SCTP_ACTIVE)
break;
- }
-
- /* Try to find an active transport. */
-
- if ((t->state == SCTP_ACTIVE) ||
- (t->state == SCTP_UNKNOWN)) {
+ /* We've reached the end, time to update path. */
+ if (trans == asoc->peer.retran_path)
break;
- } else {
- /* Keep track of the next transport in case
- * we don't find any active transport.
- */
- if (t->state != SCTP_UNCONFIRMED && !next)
- next = t;
- }
}
- if (t)
- asoc->peer.retran_path = t;
- else
- t = asoc->peer.retran_path;
+ if (trans_next != NULL)
+ asoc->peer.retran_path = trans_next;
- pr_debug("%s: association:%p addr:%pISpc\n", __func__, asoc,
- &t->ipaddr.sa);
+ pr_debug("%s: association:%p updated new path to addr:%pISpc\n",
+ __func__, asoc, &asoc->peer.retran_path->ipaddr.sa);
}
-/* Choose the transport for sending retransmit packet. */
-struct sctp_transport *sctp_assoc_choose_alter_transport(
- struct sctp_association *asoc, struct sctp_transport *last_sent_to)
+struct sctp_transport *
+sctp_assoc_choose_alter_transport(struct sctp_association *asoc,
+ struct sctp_transport *last_sent_to)
{
/* If this is the first time packet is sent, use the active path,
* else use the retran path. If the last packet was sent over the
* retran path, update the retran path and use it.
*/
- if (!last_sent_to)
+ if (last_sent_to == NULL) {
return asoc->peer.active_path;
- else {
+ } else {
if (last_sent_to == asoc->peer.retran_path)
sctp_assoc_update_retran_path(asoc);
+
return asoc->peer.retran_path;
}
}
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 "
}
}
+/* 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.
* ack chunk whose serial number matches that of the request.
*/
list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
+ if (sctp_chunk_pending(ack))
+ continue;
if (ack->subh.addip_hdr->serial == serial) {
sctp_chunk_hold(ack);
return ack;
projects / platform / adaptation / renesas_rcar / renesas_kernel.git / blobdiff