[SCTP]: Set assoc_id correctly during INIT collision.

During the INIT/COOKIE-ACK collision cases, it's possible to get
into a situation where the association id is not yet set at the time
of the user event generation.  As a result, user events have an
association id set to 0 which will confuse applications.

This happens if we hit case B of duplicate cookie processing.
In the particular example found and provided by Oscar Isaula
<Oscar.Isaula@motorola.com>, flow looks like this:
A				B
---- INIT------->  (lost)
	    <---------INIT------
---- INIT-ACK--->
	    <------ Cookie ECHO

When the Cookie Echo is received, we end up trying to update the
association that was created on A as a result of the (lost) INIT,
but that association doesn't have the ID set yet.

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

1 files changed, 11 insertions, 18 deletions

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 9e28a5d..f02ce3d 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1656,7 +1656,6 @@ static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
 					struct sctp_association *new_asoc)
 {
 	sctp_init_chunk_t *peer_init;
-	struct sctp_ulpevent *ev;
 	struct sctp_chunk *repl;
 
 	/* new_asoc is a brand-new association, so these are not yet
@@ -1687,34 +1686,28 @@ static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
 	 * D) IMPLEMENTATION NOTE: An implementation may choose to
 	 * send the Communication Up notification to the SCTP user
 	 * upon reception of a valid COOKIE ECHO chunk.
+	 *
+	 * Sadly, this needs to be implemented as a side-effect, because
+	 * we are not guaranteed to have set the association id of the real
+	 * association and so these notifications need to be delayed until
+	 * the association id is allocated.
 	 */
-	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0,
-					     new_asoc->c.sinit_num_ostreams,
-					     new_asoc->c.sinit_max_instreams,
-					     NULL, GFP_ATOMIC);
-	if (!ev)
-		goto nomem_ev;
 
-	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
 
 	/* Sockets API Draft Section 5.3.1.6
 	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
 	 * delivers this notification to inform the application that of the
 	 * peers requested adaptation layer.
+	 *
+	 * This also needs to be done as a side effect for the same reason as
+	 * above.
 	 */
-	if (asoc->peer.adaptation_ind) {
-		ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
-		if (!ev)
-			goto nomem_ev;
-
-		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
-				SCTP_ULPEVENT(ev));
-	}
+	if (asoc->peer.adaptation_ind)
+		sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
 
 	return SCTP_DISPOSITION_CONSUME;
 
-nomem_ev:
-	sctp_chunk_free(repl);
 nomem:
 	return SCTP_DISPOSITION_NOMEM;
 }