session: support for cl port reuse

Adds support for connectionless listener port reuse. Until now, cl
listeners had fifos allocated to them and therefore only one app worker
could ever listen, i.e., a session cannot have multiple fifos.

To circumvent the limitation, this separates the fifos from the listener
by allocating new cl sessions for each app worker that reuses the app
listener. Flows are hashed to app worker cl sessions but, for now, this
is not a consistent/fixed hash.

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Ic6533cd47f2765903669f88c288bd592fb17a19e

1 files changed, 19 insertions, 12 deletions

diff --git a/src/vnet/udp/udp_input.c b/src/vnet/udp/udp_input.c
index 66f6229efa6..9cabfdf73cd 100644
--- a/src/vnet/udp/udp_input.c
+++ b/src/vnet/udp/udp_input.c
@@ -136,39 +136,46 @@ udp_connection_enqueue (udp_connection_t * uc0, session_t * s0,
   int wrote0;
 
   if (!(uc0->flags & UDP_CONN_F_CONNECTED))
-    clib_spinlock_lock (&uc0->rx_lock);
+    {
+      clib_spinlock_lock (&uc0->rx_lock);
+
+      wrote0 = session_enqueue_dgram_connection_cl (
+	s0, hdr0, b, TRANSPORT_PROTO_UDP, queue_event);
+
+      clib_spinlock_unlock (&uc0->rx_lock);
+
+      /* Expect cl udp enqueue to fail because fifo enqueue */
+      if (PREDICT_FALSE (wrote0 == 0))
+	*error0 = UDP_ERROR_FIFO_FULL;
+
+      return;
+    }
 
   if (svm_fifo_max_enqueue_prod (s0->rx_fifo)
       < hdr0->data_length + sizeof (session_dgram_hdr_t))
     {
       *error0 = UDP_ERROR_FIFO_FULL;
-      goto unlock_rx_lock;
+      return;
     }
 
   /* If session is owned by another thread and rx event needed,
    * enqueue event now while we still have the peeker lock */
   if (s0->thread_index != thread_index)
     {
-      wrote0 = session_enqueue_dgram_connection_cl (
+      wrote0 = session_enqueue_dgram_connection2 (
 	s0, hdr0, b, TRANSPORT_PROTO_UDP,
-	/* queue event */ queue_event && !svm_fifo_has_event (s0->rx_fifo));
+	queue_event && !svm_fifo_has_event (s0->rx_fifo));
     }
   else
     {
-      wrote0 = session_enqueue_dgram_connection (s0, hdr0, b,
-						 TRANSPORT_PROTO_UDP,
-						 queue_event);
+      wrote0 = session_enqueue_dgram_connection (
+	s0, hdr0, b, TRANSPORT_PROTO_UDP, queue_event);
     }
 
   /* In some rare cases, session_enqueue_dgram_connection can fail because a
    * chunk cannot be allocated in the RX FIFO */
   if (PREDICT_FALSE (wrote0 == 0))
     *error0 = UDP_ERROR_FIFO_NOMEM;
-
-unlock_rx_lock:
-
-  if (!(uc0->flags & UDP_CONN_F_CONNECTED))
-    clib_spinlock_unlock (&uc0->rx_lock);
 }
 
 always_inline session_t *