VPP-659 TCP improvements

[vpp.git] / src / vnet / tcp / tcp_input.c

diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 0a907d0..f19fbf8 100644 (file)
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -274,10 +274,7 @@ tcp_segment_validate (vlib_main_t * vm, tcp_connection_t * tc0,
   /* 2nd: check the RST bit */
   if (tcp_rst (th0))
     {
-      /* Notify session that connection has been reset. Switch
-       * state to closed and await for session to do the cleanup. */
-      stream_session_reset_notify (&tc0->connection);
-      tc0->state = TCP_STATE_CLOSED;
+      tcp_connection_reset (tc0);
       return -1;
     }
 
@@ -1023,6 +1020,12 @@ tcp46_established_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
                                    my_thread_index);
 
+         if (PREDICT_FALSE (tc0 == 0))
+           {
+             error0 = TCP_ERROR_INVALID_CONNECTION;
+             goto drop;
+           }
+
          /* Checksum computed by ipx_local no need to compute again */
 
          if (is_ip4)
@@ -1072,12 +1075,12 @@ tcp46_established_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          /* 8: check the FIN bit */
          if (tcp_fin (th0))
            {
-             /* Send ACK and enter CLOSE-WAIT */
-             tcp_make_ack (tc0, b0);
-             tcp_connection_force_ack (tc0, b0);
-             next0 = tcp_next_output (tc0->c_is_ip4);
+             /* Enter CLOSE-WAIT and notify session. Don't send ACK, instead
+              * wait for session to call close. To avoid lingering
+              * in CLOSE-WAIT, set timer (reuse WAITCLOSE). */
              tc0->state = TCP_STATE_CLOSE_WAIT;
              stream_session_disconnect_notify (&tc0->connection);
+             tcp_timer_set (tc0, TCP_TIMER_WAITCLOSE, TCP_CLOSEWAIT_TIME);
            }
 
        drop:
@@ -1468,7 +1471,7 @@ VLIB_REGISTER_NODE (tcp6_syn_sent_node) =
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_syn_sent_node, tcp6_syn_sent_rcv);
 /**
- * Handles reception for all states except LISTEN, SYN-SEND and ESTABLISHED
+ * Handles reception for all states except LISTEN, SYN-SENT and ESTABLISHED
  * as per RFC793 p. 64
  */
 always_inline uword
@@ -1511,6 +1514,11 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          b0 = vlib_get_buffer (vm, bi0);
          tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
                                    my_thread_index);
+         if (PREDICT_FALSE (tc0 == 0))
+           {
+             error0 = TCP_ERROR_INVALID_CONNECTION;
+             goto drop;
+           }
 
          /* Checksum computed by ipx_local no need to compute again */
 
@@ -1587,7 +1595,8 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
              /* Shoulder tap the server */
              stream_session_accept_notify (&tc0->connection);
 
-             tcp_timer_reset (tc0, TCP_TIMER_RETRANSMIT_SYN);
+             /* Reset SYN-ACK retransmit timer */
+             tcp_timer_reset (tc0, TCP_TIMER_RETRANSMIT);
              break;
            case TCP_STATE_ESTABLISHED:
              /* We can get packets in established state here because they
@@ -1602,9 +1611,14 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
               * continue processing in that state. */
              if (tcp_rcv_ack (tc0, b0, tcp0, &next0, &error0))
                goto drop;
-             tc0->state = TCP_STATE_FIN_WAIT_2;
-             /* Stop all timers, 2MSL will be set lower */
-             tcp_connection_timers_reset (tc0);
+
+             /* If FIN is ACKed */
+             if (tc0->snd_una == tc0->snd_una_max)
+               {
+                 tc0->state = TCP_STATE_FIN_WAIT_2;
+                 /* Stop all timers, 2MSL will be set lower */
+                 tcp_connection_timers_reset (tc0);
+               }
              break;
            case TCP_STATE_FIN_WAIT_2:
              /* In addition to the processing for the ESTABLISHED state, if
@@ -1639,7 +1653,17 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
              if (!tcp_rcv_ack_is_acceptable (tc0, b0))
                goto drop;
 
-             tcp_connection_del (tc0);
+             tc0->state = TCP_STATE_CLOSED;
+
+             /* Don't delete the connection/session yet. Instead, wait a
+              * reasonable amount of time until the pipes are cleared. In
+              * particular, this makes sure that we won't have dead sessions
+              * when processing events on the tx path */
+             tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_CLEANUP_TIME);
+
+             /* Stop retransmit */
+             tcp_timer_reset (tc0, TCP_TIMER_RETRANSMIT);
+
              goto drop;
 
              break;
@@ -1684,7 +1708,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
            case TCP_STATE_SYN_RCVD:
              /* Send FIN-ACK notify app and enter CLOSE-WAIT */
              tcp_connection_timers_reset (tc0);
-             tcp_make_finack (tc0, b0);
+             tcp_make_fin (tc0, b0);
              next0 = tcp_next_output (tc0->c_is_ip4);
              stream_session_disconnect_notify (&tc0->connection);
              tc0->state = TCP_STATE_CLOSE_WAIT;
@@ -1697,12 +1721,12 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
            case TCP_STATE_FIN_WAIT_1:
              tc0->state = TCP_STATE_TIME_WAIT;
              tcp_connection_timers_reset (tc0);
-             tcp_timer_set (tc0, TCP_TIMER_2MSL, TCP_2MSL_TIME);
+             tcp_timer_set (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME);
              break;
            case TCP_STATE_FIN_WAIT_2:
              /* Got FIN, send ACK! */
              tc0->state = TCP_STATE_TIME_WAIT;
-             tcp_timer_set (tc0, TCP_TIMER_2MSL, TCP_2MSL_TIME);
+             tcp_timer_set (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME);
              tcp_make_ack (tc0, b0);
              next0 = tcp_next_output (is_ip4);
              break;
@@ -1710,7 +1734,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
              /* Remain in the TIME-WAIT state. Restart the 2 MSL time-wait
               * timeout.
               */
-             tcp_timer_update (tc0, TCP_TIMER_2MSL, TCP_2MSL_TIME);
+             tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME);
              break;
            }
 
@@ -2113,6 +2137,7 @@ tcp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          n_left_to_next -= 1;
 
          b0 = vlib_get_buffer (vm, bi0);
+         vnet_buffer (b0)->tcp.flags = 0;
 
          if (is_ip4)
            {
@@ -2168,7 +2193,6 @@ tcp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
              /* Send reset */
              next0 = TCP_INPUT_NEXT_RESET;
              error0 = TCP_ERROR_NO_LISTENER;
-             vnet_buffer (b0)->tcp.flags = 0;
            }
 
          b0->error = error0 ? node->errors[error0] : 0;
@@ -2288,6 +2312,7 @@ do {                                                              \
   _(ESTABLISHED, TCP_FLAG_FIN, TCP_INPUT_NEXT_ESTABLISHED, TCP_ERROR_NONE);
   _(ESTABLISHED, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_ESTABLISHED,
     TCP_ERROR_NONE);
+  _(ESTABLISHED, TCP_FLAG_RST, TCP_INPUT_NEXT_ESTABLISHED, TCP_ERROR_NONE);
   /* ACK or FIN-ACK to our FIN */
   _(FIN_WAIT_1, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
   _(FIN_WAIT_1, TCP_FLAG_ACK | TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS,