[SCTP]: Flush fragment queue when exiting partial delivery.

At the end of partial delivery, we may have complete messages
sitting on the fragment queue.  These messages are stuck there
until a new fragment arrives.  This can comletely stall a
given association.  When clearing partial delivery state, flush
any complete messages from the fragment queue and send them on
their way up.

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

1 files changed, 33 insertions, 0 deletions

diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
index 4908041ffb31..1733fa29a501 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -53,6 +53,7 @@ static struct sctp_ulpevent * sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
                                               struct sctp_ulpevent *);
 static struct sctp_ulpevent * sctp_ulpq_order(struct sctp_ulpq *,
                                               struct sctp_ulpevent *);
+static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq);
 
 /* 1st Level Abstractions */
 
@@ -190,6 +191,7 @@ static void sctp_ulpq_set_pd(struct sctp_ulpq *ulpq)
 static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
 {
         ulpq->pd_mode = 0;
+        sctp_ulpq_reasm_drain(ulpq);
         return sctp_clear_pd(ulpq->asoc->base.sk, ulpq->asoc);
 }
 
@@ -699,6 +701,37 @@ void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *ulpq, __u32 fwd_tsn)
         }
 }
 
+/*
+ * Drain the reassembly queue.  If we just cleared parted delivery, it
+ * is possible that the reassembly queue will contain already reassembled
+ * messages.  Retrieve any such messages and give them to the user.
+ */
+static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq)
+{
+        struct sctp_ulpevent *event = NULL;
+        struct sk_buff_head temp;
+
+        if (skb_queue_empty(&ulpq->reasm))
+                return;
+
+        while ((event = sctp_ulpq_retrieve_reassembled(ulpq)) != NULL) {
+                /* Do ordering if needed.  */
+                if ((event) && (event->msg_flags & MSG_EOR)){
+                        skb_queue_head_init(&temp);
+                        __skb_queue_tail(&temp, sctp_event2skb(event));
+
+                        event = sctp_ulpq_order(ulpq, event);
+                }
+
+                /* Send event to the ULP.  'event' is the
+                 * sctp_ulpevent for  very first SKB on the  temp' list.
+                 */
+                if (event)
+                        sctp_ulpq_tail_event(ulpq, event);
+        }
+}
+
+
 /* Helper function to gather skbs that have possibly become
  * ordered by an an incoming chunk.
  */