[SCTP]: Remove temporary associations from backlog and hash.

Every time SCTP creates a temporary association, the stack hashes it,
puts it on a list of endpoint associations and increments the backlog.
However, the lifetime of a temporary association is the processing time
of a current packet and it's destroyed after that. In fact, we don't
really want anyone else finding this association. There is no reason to
do this extra work.

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

3 files changed, 24 insertions, 4 deletions

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 27329ce9c311..ed0445fe85e7 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -346,11 +346,18 @@ void sctp_association_free(struct sctp_association *asoc)
         struct list_head *pos, *temp;
         int i;
 
-        list_del(&asoc->asocs);
+        /* Only real associations count against the endpoint, so
+         * don't bother for if this is a temporary association.
+         */
+        if (!asoc->temp) {
+                list_del(&asoc->asocs);
 
-        /* Decrement the backlog value for a TCP-style listening socket. */
-        if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
-                sk->sk_ack_backlog--;
+                /* Decrement the backlog value for a TCP-style listening
+                 * socket.
+                 */
+                if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
+                        sk->sk_ack_backlog--;
+        }
 
         /* Mark as dead, so other users can know this structure is
          * going away.
diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
index 35c49ff2d062..9b6b394b66f6 100644
--- a/net/sctp/endpointola.c
+++ b/net/sctp/endpointola.c
@@ -144,6 +144,13 @@ void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 {
         struct sock *sk = ep->base.sk;
 
+        /* If this is a temporary association, don't bother
+         * since we'll be removing it shortly and don't
+         * want anyone to find it anyway.
+         */
+        if (asoc->temp)
+                return;
+
         /* Now just add it to our list of asocs */
         list_add_tail(&asoc->asocs, &ep->asocs);
 
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 99c0501ca513..6d82f400d13c 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -771,6 +771,9 @@ static void __sctp_hash_established(struct sctp_association *asoc)
 /* Add an association to the hash. Local BH-safe. */
 void sctp_hash_established(struct sctp_association *asoc)
 {
+        if (asoc->temp)
+                return;
+
         sctp_local_bh_disable();
         __sctp_hash_established(asoc);
         sctp_local_bh_enable();
@@ -804,6 +807,9 @@ static void __sctp_unhash_established(struct sctp_association *asoc)
 /* Remove association from the hash table.  Local BH-safe. */
 void sctp_unhash_established(struct sctp_association *asoc)
 {
+        if (asoc->temp)
+                return;
+
         sctp_local_bh_disable();
         __sctp_unhash_established(asoc);
         sctp_local_bh_enable();