Fix tcp multi buffer segments retransmission

- Fix tcp/udp sw checksum computation
- Fix allocation of multi buffer tcp segments for retransmits
- Send FIN only if/when tx fifo is empty

Change-Id: I2e43a14b87a72c9e547b4339b9a51811cf5732c4
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index 997df76f545..a17262fa7b4 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -116,7 +116,8 @@ extern timer_expiration_handler tcp_timer_retransmit_syn_handler;
   _(RECOVERY, "Recovery on")                    \
   _(FAST_RECOVERY, "Fast Recovery on")		\
   _(FR_1_SMSS, "Sent 1 SMSS")			\
-  _(HALF_OPEN_DONE, "Half-open completed")
+  _(HALF_OPEN_DONE, "Half-open completed")	\
+  _(FINPNDG, "FIN pending")
 
 typedef enum _tcp_connection_flag_bits
 {
@@ -404,6 +405,9 @@ typedef struct _tcp_main
 
   /** Port allocator random number generator seed */
   u32 port_allocator_seed;
+
+  /** vlib buffer size */
+  u32 bytes_per_buffer;
 } tcp_main_t;
 
 extern tcp_main_t tcp_main;
@@ -587,6 +591,14 @@ tcp_available_snd_space (const tcp_connection_t * tc)
   return available_wnd - flight_size;
 }
 
+always_inline u8
+tcp_is_lost_fin (tcp_connection_t * tc)
+{
+  if ((tc->flags & TCP_CONN_FINSNT) && tc->snd_una_max - tc->snd_una == 1)
+    return 1;
+  return 0;
+}
+
 i32 tcp_rcv_wnd_available (tcp_connection_t * tc);
 u32 tcp_snd_space (tcp_connection_t * tc);
 void tcp_update_rcv_wnd (tcp_connection_t * tc);
@@ -621,8 +633,8 @@ tcp_update_time (f64 now, u32 thread_index)
 u32 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b);
 
 u32
-tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b,
-				u32 offset, u32 max_bytes);
+tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset,
+				u32 max_bytes, vlib_buffer_t ** b);
 
 void tcp_connection_timers_init (tcp_connection_t * tc);
 void tcp_connection_timers_reset (tcp_connection_t * tc);