2 files changed, 20 insertions, 0 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;