[SCTP]: Implement sac_info field in SCTP_ASSOC_CHANGE notification.

As stated in the sctp socket api draft:

   sac_info: variable

   If the sac_state is SCTP_COMM_LOST and an ABORT chunk was received
   for this association, sac_info[] contains the complete ABORT chunk as
   defined in the SCTP specification RFC2960 [RFC2960] section 3.3.7.

We now save received ABORT chunks into the sac_info field and pass that
to the user.

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

1 files changed, 42 insertions, 7 deletions

diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index 2e11bc8d5d35..661ea2dd78ba 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -131,19 +131,54 @@ static inline void sctp_ulpevent_release_owner(struct sctp_ulpevent *event)
 struct sctp_ulpevent  *sctp_ulpevent_make_assoc_change(
         const struct sctp_association *asoc,
         __u16 flags, __u16 state, __u16 error, __u16 outbound,
-        __u16 inbound, gfp_t gfp)
+        __u16 inbound, struct sctp_chunk *chunk, gfp_t gfp)
 {
         struct sctp_ulpevent *event;
         struct sctp_assoc_change *sac;
         struct sk_buff *skb;
 
-        event = sctp_ulpevent_new(sizeof(struct sctp_assoc_change),
+        /* If the lower layer passed in the chunk, it will be
+         * an ABORT, so we need to include it in the sac_info.
+         */
+        if (chunk) {
+                /* sctp_inqu_pop() has allready pulled off the chunk
+                 * header.  We need to put it back temporarily
+                 */
+                skb_push(chunk->skb, sizeof(sctp_chunkhdr_t));
+
+                /* Copy the chunk data to a new skb and reserve enough
+                 * head room to use as notification.
+                 */
+                skb = skb_copy_expand(chunk->skb,
+                                      sizeof(struct sctp_assoc_change), 0, gfp);
+
+                if (!skb)
+                        goto fail;
+
+                /* put back the chunk header now that we have a copy */
+                skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
+
+                /* Embed the event fields inside the cloned skb.  */
+                event = sctp_skb2event(skb);
+                sctp_ulpevent_init(event, MSG_NOTIFICATION, skb->truesize);
+
+                /* Include the notification structure */
+                sac = (struct sctp_assoc_change *)
+                        skb_push(skb, sizeof(struct sctp_assoc_change));
+
+                /* Trim the buffer to the right length.  */
+                skb_trim(skb, sizeof(struct sctp_assoc_change) +
+                         ntohs(chunk->chunk_hdr->length));
+        } else {
+                event = sctp_ulpevent_new(sizeof(struct sctp_assoc_change),
                                   MSG_NOTIFICATION, gfp);
-        if (!event)
-                goto fail;
-        skb = sctp_event2skb(event);
-        sac = (struct sctp_assoc_change *)
-                skb_put(skb, sizeof(struct sctp_assoc_change));
+                if (!event)
+                        goto fail;
+
+                skb = sctp_event2skb(event);
+                sac = (struct sctp_assoc_change *) skb_put(skb,
+                                        sizeof(struct sctp_assoc_change));
+        }
 
         /* Socket Extensions for SCTP
          * 5.3.1.1 SCTP_ASSOC_CHANGE