commit 5a41fd5ee7af8d39106d5fc5de7f2d17d7356b30
author Florin Coras <fcoras@cisco.com> Mon Apr 19 10:17:26 2021 -0700
committer Dave Barach <openvpp@barachs.net> Tue Apr 20 16:48:16 2021 +0000
tree b9e8c4dead552939a116ba1c02c6f6bc548e5d66
parent 005d1e4d4822454363c4a0fa3a1d8b33a14ba6e8

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

src/vnet/tcp/tcp.c

diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index e447fac..a6c1e21 100644
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -1272,6 +1272,27 @@
   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 @@
   .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,

src/vnet/tcp/tcp_output.c

diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 928e824..dac50b5 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -463,7 +463,10 @@
   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);
 }