tcp: req app deq notification on fifo full

If fifo full, default to requesting an app deq notification and forcing
an ack (window update) if zero rcv window sent is still active.

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Iade7e1722503da149c62c465c472edbb0a5599f7

diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index 44cbaeb..8b59133 100644 (file)
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -574,6 +574,13 @@ transport_rx_fifo_has_ooo_data (transport_connection_t * tc)
   return svm_fifo_has_ooo_data (s->rx_fifo);
 }
 
+always_inline void
+transport_rx_fifo_req_deq_ntf (transport_connection_t *tc)
+{
+  session_t *s = session_get (tc->s_index, tc->thread_index);
+  svm_fifo_add_want_deq_ntf (s->rx_fifo, SVM_FIFO_WANT_DEQ_NOTIF);
+}
+
 always_inline clib_time_type_t
 transport_time_now (u32 thread_index)
 {

diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index e447fac..a6c1e21 100644 (file)
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -1272,6 +1272,27 @@ tcp_session_flush_data (transport_connection_t * tconn)
   tc->psh_seq = tc->snd_una + transport_max_tx_dequeue (tconn) - 1;
 }
 
+static int
+tcp_session_app_rx_evt (transport_connection_t *conn)
+{
+  tcp_connection_t *tc = (tcp_connection_t *) conn;
+  u32 min_free, lo = 4 << 10, hi = 128 << 10;
+
+  if (!(tc->flags & TCP_CONN_ZERO_RWND_SENT))
+    return 0;
+
+  min_free = clib_clamp (transport_rx_fifo_size (conn) >> 3, lo, hi);
+  if (transport_max_rx_enqueue (conn) < min_free)
+    {
+      transport_rx_fifo_req_deq_ntf (conn);
+      return 0;
+    }
+
+  tcp_send_ack (tc);
+
+  return 0;
+}
+
 /* *INDENT-OFF* */
 const static transport_proto_vft_t tcp_proto = {
   .enable = vnet_tcp_enable_disable,
@@ -1291,6 +1312,7 @@ const static transport_proto_vft_t tcp_proto = {
   .update_time = tcp_update_time,
   .flush_data = tcp_session_flush_data,
   .custom_tx = tcp_session_custom_tx,
+  .app_rx_evt = tcp_session_app_rx_evt,
   .format_connection = format_tcp_session,
   .format_listener = format_tcp_listener_session,
   .format_half_open = format_tcp_half_open_session,

diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 928e824..dac50b5 100644 (file)
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -463,7 +463,10 @@ tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state,
   vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
 
   if (wnd == 0)
-    tcp_zero_rwnd_sent_on (tc);
+    {
+      transport_rx_fifo_req_deq_ntf (&tc->connection);
+      tcp_zero_rwnd_sent_on (tc);
+    }
   else
     tcp_zero_rwnd_sent_off (tc);
 }