[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, 13 insertions, 11 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 8a0808eab811..fa87873fee76 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -744,6 +744,7 @@ struct sctp_chunk {
         __u8 tsn_missing_report; /* Data chunk missing counter. */
         __u8 data_accepted;     /* At least 1 chunk in this packet accepted */
         __u8 auth;              /* IN: was auth'ed | OUT: needs auth */
+        __u8 has_asconf;        /* IN: have seen an asconf before */
 };
 
 void sctp_chunk_hold(struct sctp_chunk *);
@@ -1785,20 +1786,16 @@ struct sctp_association {
          */
         struct sctp_chunk *addip_last_asconf;
 
-        /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
+        /* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
          *
-         * IMPLEMENTATION NOTE: As an optimization a receiver may wish
-         * to save the last ASCONF-ACK for some predetermined period
-         * of time and instead of re-processing the ASCONF (with the
-         * same serial number) it may just re-transmit the
-         * ASCONF-ACK. It may wish to use the arrival of a new serial
-         * number to discard the previously saved ASCONF-ACK or any
-         * other means it may choose to expire the saved ASCONF-ACK.
+         * This is needed to implement itmes E1 - E4 of the updated
+         * spec.  Here is the justification:
          *
-         * [This is our saved ASCONF-ACK.  We invalidate it when a new
-         * ASCONF serial number arrives.]
+         * Since the peer may bundle multiple ASCONF chunks toward us,
+         * we now need the ability to cache multiple ACKs.  The section
+         * describes in detail how they are cached and cleaned up.
          */
-        struct sctp_chunk *addip_last_asconf_ack;
+        struct list_head asconf_ack_list;
 
         /* These ASCONF chunks are waiting to be sent.
          *
@@ -1947,6 +1944,11 @@ int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
                                          struct sctp_cookie*,
                                          gfp_t gfp);
 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
+void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
+struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
+                                        const struct sctp_association *asoc,
+                                        __be32 serial);
+
 
 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
                         const union sctp_addr *ss2);