1 files changed, 60 insertions, 4 deletions

diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
index ac80c34f6c2c..0fa4d4d4df17 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -177,6 +177,15 @@ int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc)
         return 0;
 }
 
+/* Set the pd_mode on the socket and ulpq */
+static void sctp_ulpq_set_pd(struct sctp_ulpq *ulpq)
+{
+        struct sctp_sock *sp = sctp_sk(ulpq->asoc->base.sk);
+
+        atomic_inc(&sp->pd_mode);
+        ulpq->pd_mode = 1;
+}
+
 /* Clear the pd_mode and restart any pending messages waiting for delivery. */
 static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
 {
@@ -401,6 +410,11 @@ static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_u
         struct sk_buff *first_frag = NULL;
         __u32 ctsn, next_tsn;
         struct sctp_ulpevent *retval = NULL;
+        struct sk_buff *pd_first = NULL;
+        struct sk_buff *pd_last = NULL;
+        size_t pd_len = 0;
+        struct sctp_association *asoc;
+        u32 pd_point;
 
         /* Initialized to 0 just to avoid compiler warning message.  Will
          * never be used with this value. It is referenced only after it
@@ -416,6 +430,10 @@ static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_u
          * we expect to find the remaining middle fragments and the last
          * fragment in order. If not, first_frag is reset to NULL and we
          * start the next pass when we find another first fragment.
+         *
+         * There is a potential to do partial delivery if user sets
+         * SCTP_PARTIAL_DELIVERY_POINT option. Lets count some things here
+         * to see if can do PD.
          */
         skb_queue_walk(&ulpq->reasm, pos) {
                 cevent = sctp_skb2event(pos);
@@ -423,14 +441,32 @@ static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_u
 
                 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
                 case SCTP_DATA_FIRST_FRAG:
+                        /* If this "FIRST_FRAG" is the first
+                         * element in the queue, then count it towards
+                         * possible PD.
+                         */
+                        if (pos == ulpq->reasm.next) {
+                            pd_first = pos;
+                            pd_last = pos;
+                            pd_len = pos->len;
+                        } else {
+                            pd_first = NULL;
+                            pd_last = NULL;
+                            pd_len = 0;
+                        }
+
                         first_frag = pos;
                         next_tsn = ctsn + 1;
                         break;
 
                 case SCTP_DATA_MIDDLE_FRAG:
-                        if ((first_frag) && (ctsn == next_tsn))
+                        if ((first_frag) && (ctsn == next_tsn)) {
                                 next_tsn++;
-                        else
+                                if (pd_first) {
+                                    pd_last = pos;
+                                    pd_len += pos->len;
+                                }
+                        } else
                                 first_frag = NULL;
                         break;
 
@@ -441,7 +477,28 @@ static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_u
                                 first_frag = NULL;
                         break;
                 };
+        }
+
+        asoc = ulpq->asoc;
+        if (pd_first) {
+                /* Make sure we can enter partial deliver.
+                 * We can trigger partial delivery only if framgent
+                 * interleave is set, or the socket is not already
+                 * in  partial delivery.
+                 */
+                if (!sctp_sk(asoc->base.sk)->frag_interleave &&
+                    atomic_read(&sctp_sk(asoc->base.sk)->pd_mode))
+                        goto done;
 
+                cevent = sctp_skb2event(pd_first);
+                pd_point = sctp_sk(asoc->base.sk)->pd_point;
+                if (pd_point && pd_point <= pd_len) {
+                        retval = sctp_make_reassembled_event(&ulpq->reasm,
+                                                             pd_first,
+                                                             pd_last);
+                        if (retval)
+                                sctp_ulpq_set_pd(ulpq);
+                }
         }
 done:
         return retval;
@@ -882,8 +939,7 @@ void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
                 /* Send event to the ULP.   */
                 if (event) {
                         sctp_ulpq_tail_event(ulpq, event);
-                        atomic_inc(&sp->pd_mode);
-                        ulpq->pd_mode = 1;
+                        sctp_ulpq_set_pd(ulpq);
                         return;
                 }
         }