[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, 56 insertions, 2 deletions

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 61bebb9b96e6..a016e78061f4 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -61,6 +61,7 @@
 
 /* Forward declarations for internal functions. */
 static void sctp_assoc_bh_rcv(struct work_struct *work);
+static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
 
 
 /* 1st Level Abstractions. */
@@ -242,6 +243,7 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
         asoc->addip_serial = asoc->c.initial_tsn;
 
         INIT_LIST_HEAD(&asoc->addip_chunk_list);
+        INIT_LIST_HEAD(&asoc->asconf_ack_list);
 
         /* Make an empty list of remote transport addresses.  */
         INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
@@ -431,8 +433,7 @@ void sctp_association_free(struct sctp_association *asoc)
         asoc->peer.transport_count = 0;
 
         /* Free any cached ASCONF_ACK chunk. */
-        if (asoc->addip_last_asconf_ack)
-                sctp_chunk_free(asoc->addip_last_asconf_ack);
+        sctp_assoc_free_asconf_acks(asoc);
 
         /* Free any cached ASCONF chunk. */
         if (asoc->addip_last_asconf)
@@ -1485,3 +1486,56 @@ retry:
         asoc->assoc_id = (sctp_assoc_t) assoc_id;
         return error;
 }
+
+/* Free asconf_ack cache */
+static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
+{
+        struct sctp_chunk *ack;
+        struct sctp_chunk *tmp;
+
+        list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
+                                transmitted_list) {
+                list_del_init(&ack->transmitted_list);
+                sctp_chunk_free(ack);
+        }
+}
+
+/* Clean up the ASCONF_ACK queue */
+void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
+{
+        struct sctp_chunk *ack;
+        struct sctp_chunk *tmp;
+
+        /* We can remove all the entries from the queue upto
+         * the "Peer-Sequence-Number".
+         */
+        list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
+                                transmitted_list) {
+                if (ack->subh.addip_hdr->serial ==
+                                htonl(asoc->peer.addip_serial))
+                        break;
+
+                list_del_init(&ack->transmitted_list);
+                sctp_chunk_free(ack);
+        }
+}
+
+/* Find the ASCONF_ACK whose serial number matches ASCONF */
+struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
+                                        const struct sctp_association *asoc,
+                                        __be32 serial)
+{
+        struct sctp_chunk *ack = NULL;
+
+        /* Walk through the list of cached ASCONF-ACKs and find the
+         * ack chunk whose serial number matches that of the request.
+         */
+        list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
+                if (ack->subh.addip_hdr->serial == serial) {
+                        sctp_chunk_hold(ack);
+                        break;
+                }
+        }
+
+        return ack;
+}