3 files changed, 22 insertions, 2 deletions
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index e92b1f079d6..10bae273d85 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -582,6 +582,19 @@ transport_rx_fifo_has_ooo_data (transport_connection_t * tc)
   return svm_fifo_has_ooo_data (s->rx_fifo);
 }
 
+always_inline u32
+transport_tx_fifo_has_dgram (transport_connection_t *tc)
+{
+  session_t *s = session_get (tc->s_index, tc->thread_index);
+  u32 max_deq = svm_fifo_max_dequeue_cons (s->tx_fifo);
+  session_dgram_pre_hdr_t phdr;
+
+  if (max_deq <= sizeof (session_dgram_hdr_t))
+    return 0;
+  svm_fifo_peek (s->tx_fifo, 0, sizeof (phdr), (u8 *) &phdr);
+  return max_deq >= phdr.data_length + sizeof (session_dgram_hdr_t);
+}
+
 always_inline void
 transport_rx_fifo_req_deq_ntf (transport_connection_t *tc)
 {
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index f652f2e9a1c..6d1b6bdf2ae 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -1236,6 +1236,13 @@ session_tx_set_dequeue_params (vlib_main_t * vm, session_tx_context_t * ctx,
 	      ctx->max_len_to_snd = 0;
 	      return;
 	    }
+	  /* We cannot be sure apps have not enqueued incomplete dgrams */
+	  if (PREDICT_FALSE (ctx->max_dequeue <
+			     ctx->hdr.data_length + sizeof (ctx->hdr)))
+	    {
+	      ctx->max_len_to_snd = 0;
+	      return;
+	    }
 	  ASSERT (ctx->hdr.data_length > ctx->hdr.data_offset);
 	  len = ctx->hdr.data_length - ctx->hdr.data_offset;
 
diff --git a/src/vnet/udp/udp.c b/src/vnet/udp/udp.c
index b3c410a2330..a8e013001e8 100644
--- a/src/vnet/udp/udp.c
+++ b/src/vnet/udp/udp.c
@@ -317,7 +317,7 @@ udp_push_header (transport_connection_t *tc, vlib_buffer_t **bs, u32 n_bufs)
 
   if (PREDICT_FALSE (uc->flags & UDP_CONN_F_CLOSING))
     {
-      if (!transport_max_tx_dequeue (&uc->connection))
+      if (!transport_tx_fifo_has_dgram (&uc->connection))
 	udp_connection_program_cleanup (uc);
     }
 
@@ -343,7 +343,7 @@ udp_session_close (u32 connection_index, u32 thread_index)
   if (!uc || (uc->flags & UDP_CONN_F_MIGRATED))
     return;
 
-  if (!transport_max_tx_dequeue (&uc->connection))
+  if (!transport_tx_fifo_has_dgram (&uc->connection))
     udp_connection_program_cleanup (uc);
   else
     uc->flags |= UDP_CONN_F_CLOSING;