[SCTP]: Update ASCONF processing to conform to spec.

The processing of the ASCONF chunks has changed a lot in the
spec.  New items are:
    1. A list of ASCONF-ACK chunks is now cached
    2. The source of the packet is used in response.
    3. New handling for unexpect ASCONF chunks.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 2 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index fa76f235169b..a42af865c2ef 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -716,7 +716,29 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
                 new_transport = chunk->transport;
 
                 if (!new_transport) {
-                        new_transport = asoc->peer.active_path;
+                        /*
+                         * If we have a prior transport pointer, see if
+                         * the destination address of the chunk
+                         * matches the destination address of the
+                         * current transport.  If not a match, then
+                         * try to look up the transport with a given
+                         * destination address.  We do this because
+                         * after processing ASCONFs, we may have new
+                         * transports created.
+                         */
+                        if (transport &&
+                            sctp_cmp_addr_exact(&chunk->dest,
+                                                &transport->ipaddr))
+                                        new_transport = transport;
+                        else
+                                new_transport = sctp_assoc_lookup_paddr(asoc,
+                                                                &chunk->dest);
+
+                        /* if we still don't have a new transport, then
+                         * use the current active path.
+                         */
+                        if (!new_transport)
+                                new_transport = asoc->peer.active_path;
                 } else if ((new_transport->state == SCTP_INACTIVE) ||
                            (new_transport->state == SCTP_UNCONFIRMED)) {
                         /* If the chunk is Heartbeat or Heartbeat Ack,
@@ -729,9 +751,12 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
                          * address of the IP datagram containing the
                          * HEARTBEAT chunk to which this ack is responding.
                          * ...
+                         *
+                         * ASCONF_ACKs also must be sent to the source.
                          */
                         if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
-                            chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK)
+                            chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK &&
+                            chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK)
                                 new_transport = asoc->peer.active_path;
                 }