session tcp udp: consolidate transport snd apis

Type: improvement

Use only one api to retrieve transport send parameters. Additionally,
allow transports to request postponing and descheduling of events.

With this, tcp now requests descheduling of sessions when the
connections are stuck probing for zero snd_wnd

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I722c974f3e68fa15424c519a1fffacda43af050c

1 files changed, 42 insertions, 6 deletions

diff --git a/src/vnet/session/transport.h b/src/vnet/session/transport.h
index adc695f5e5a..b2be990947c 100644
--- a/src/vnet/session/transport.h
+++ b/src/vnet/session/transport.h
@@ -32,6 +32,21 @@ typedef struct _transport_options_t
   u8 half_open_has_fifos;
 } transport_options_t;
 
+typedef enum transport_snd_flags_
+{
+  TRANSPORT_SND_F_DESCHED = 1 << 0,
+  TRANSPORT_SND_F_POSTPONE = 1 << 1,
+  TRANSPORT_SND_N_FLAGS
+} __clib_packed transport_snd_flags_t;
+
+typedef struct transport_send_params_
+{
+  u32 snd_space;
+  u32 tx_offset;
+  u16 snd_mss;
+  transport_snd_flags_t flags;
+} transport_send_params_t;
+
 /*
  * Transport protocol virtual function table
  */
@@ -54,9 +69,8 @@ typedef struct _transport_proto_vft
    */
 
   u32 (*push_header) (transport_connection_t * tconn, vlib_buffer_t * b);
-  u16 (*send_mss) (transport_connection_t * tc);
-  u32 (*send_space) (transport_connection_t * tc);
-  u32 (*tx_fifo_offset) (transport_connection_t * tc);
+  int (*send_params) (transport_connection_t * tconn,
+		      transport_send_params_t *sp);
   void (*update_time) (f64 time_now, u8 thread_index);
   void (*flush_data) (transport_connection_t *tconn);
   int (*custom_tx) (void *session, u32 max_burst_size);
@@ -151,16 +165,38 @@ transport_app_rx_evt (transport_proto_t tp, u32 conn_index, u32 thread_index)
 }
 
 /**
- * Get maximum tx burst allowed for transport connection
+ * Get send parameters for transport connection
+ *
+ * These include maximum tx burst, mss, tx offset and other flags
+ * transport might want to provide to sessin layer
  *
  * @param tc		transport connection
+ * @param sp		send paramaters
+ *
  */
 static inline u32
-transport_connection_snd_space (transport_connection_t * tc)
+transport_connection_snd_params (transport_connection_t * tc,
+				 transport_send_params_t * sp)
 {
-  return tp_vfts[tc->proto].send_space (tc);
+  return tp_vfts[tc->proto].send_params (tc, sp);
 }
 
+static inline u8
+transport_connection_is_descheduled (transport_connection_t * tc)
+{
+  if (tc->flags & TRANSPORT_CONNECTION_F_DESCHED)
+    return 1;
+  return 0;
+}
+
+static inline void
+transport_connection_deschedule (transport_connection_t * tc)
+{
+  tc->flags |= TRANSPORT_CONNECTION_F_DESCHED;
+}
+
+void transport_connection_reschedule (transport_connection_t * tc);
+
 void transport_register_protocol (transport_proto_t transport_proto,
 				  const transport_proto_vft_t * vft,
 				  fib_protocol_t fib_proto, u32 output_node);