tcp: cleanup rcv-process and bulk buffer translation 09/32209/3
authorFlorin Coras <fcoras@cisco.com>
Wed, 5 May 2021 02:30:58 +0000 (19:30 -0700)
committerDamjan Marion <dmarion@me.com>
Wed, 5 May 2021 07:33:45 +0000 (07:33 +0000)
Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I2ca8a5e30e55a84d4567422e4b7fcf90830921d3

src/vnet/tcp/tcp_input.c

index a9159ad..2ba96a5 100644 (file)
@@ -2101,55 +2101,77 @@ VLIB_REGISTER_NODE (tcp6_syn_sent_node) =
 };
 /* *INDENT-ON* */
 
+static void
+tcp46_rcv_process_trace_frame (vlib_main_t *vm, vlib_node_runtime_t *node,
+                              u32 *from, u32 n_bufs)
+{
+  u32 thread_index = vm->thread_index;
+  tcp_connection_t *tc = 0;
+  tcp_rx_trace_t *t;
+  vlib_buffer_t *b;
+  int i;
+
+  for (i = 0; i < n_bufs; i++)
+    {
+      b = vlib_get_buffer (vm, from[i]);
+      if (!(b->flags & VLIB_BUFFER_IS_TRACED))
+       continue;
+      tc = tcp_connection_get (vnet_buffer (b)->tcp.connection_index,
+                              thread_index);
+      t = vlib_add_trace (vm, node, b, sizeof (*t));
+      tcp_set_rx_trace_data (t, tc, tcp_buffer_hdr (b), b, 1);
+    }
+}
+
 /**
  * Handles reception for all states except LISTEN, SYN-SENT and ESTABLISHED
  * as per RFC793 p. 64
  */
 always_inline uword
-tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
-                         vlib_frame_t * from_frame, int is_ip4)
+tcp46_rcv_process_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
+                         vlib_frame_t *frame, int is_ip4)
 {
-  u32 thread_index = vm->thread_index, errors = 0, *first_buffer;
+  u32 thread_index = vm->thread_index, errors, n_left_from, *from, max_deq;
   tcp_worker_ctx_t *wrk = tcp_get_worker (thread_index);
-  u32 n_left_from, *from, max_dequeue;
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
 
-  from = first_buffer = vlib_frame_vector_args (from_frame);
-  n_left_from = from_frame->n_vectors;
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+
+  if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
+    tcp46_rcv_process_trace_frame (vm, node, from, n_left_from);
+
+  vlib_get_buffers (vm, from, bufs, n_left_from);
+  b = bufs;
 
   while (n_left_from > 0)
     {
-      u32 bi0, error0 = TCP_ERROR_NONE;
-      tcp_header_t *tcp0 = 0;
-      tcp_connection_t *tc0;
-      vlib_buffer_t *b0;
-      u8 is_fin0;
-
-      bi0 = from[0];
-      from += 1;
-      n_left_from -= 1;
+      u32 error = TCP_ERROR_NONE;
+      tcp_header_t *tcp = 0;
+      tcp_connection_t *tc;
+      u8 is_fin;
 
-      b0 = vlib_get_buffer (vm, bi0);
-      tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index,
-                               thread_index);
-      if (PREDICT_FALSE (tc0 == 0))
+      tc = tcp_connection_get (vnet_buffer (b[0])->tcp.connection_index,
+                              thread_index);
+      if (PREDICT_FALSE (tc == 0))
        {
-         error0 = TCP_ERROR_INVALID_CONNECTION;
+         error = TCP_ERROR_INVALID_CONNECTION;
          goto drop;
        }
 
-      tcp0 = tcp_buffer_hdr (b0);
-      is_fin0 = tcp_is_fin (tcp0);
+      tcp = tcp_buffer_hdr (b[0]);
+      is_fin = tcp_is_fin (tcp);
 
       if (CLIB_DEBUG)
        {
-         if (!(tc0->connection.flags & TRANSPORT_CONNECTION_F_NO_LOOKUP))
+         if (!(tc->connection.flags & TRANSPORT_CONNECTION_F_NO_LOOKUP))
            {
              tcp_connection_t *tmp;
-             tmp = tcp_lookup_connection (tc0->c_fib_index, b0, thread_index,
+             tmp = tcp_lookup_connection (tc->c_fib_index, b[0], thread_index,
                                           is_ip4);
-             if (tmp->state != tc0->state)
+             if (tmp->state != tc->state)
                {
-                 if (tc0->state != TCP_STATE_CLOSED)
+                 if (tc->state != TCP_STATE_CLOSED)
                    clib_warning ("state changed");
                  goto drop;
                }
@@ -2159,9 +2181,9 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
       /*
        * Special treatment for CLOSED
        */
-      if (PREDICT_FALSE (tc0->state == TCP_STATE_CLOSED))
+      if (PREDICT_FALSE (tc->state == TCP_STATE_CLOSED))
        {
-         error0 = TCP_ERROR_CONNECTION_CLOSED;
+         error = TCP_ERROR_CONNECTION_CLOSED;
          goto drop;
        }
 
@@ -2170,19 +2192,19 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
        */
 
       /* 1-4: check SEQ, RST, SYN */
-      if (PREDICT_FALSE (tcp_segment_validate (wrk, tc0, b0, tcp0, &error0)))
+      if (PREDICT_FALSE (tcp_segment_validate (wrk, tc, b[0], tcp, &error)))
        goto drop;
 
       /* 5: check the ACK field  */
-      switch (tc0->state)
+      switch (tc->state)
        {
        case TCP_STATE_SYN_RCVD:
 
          /* Make sure the segment is exactly right */
-         if (tc0->rcv_nxt != vnet_buffer (b0)->tcp.seq_number || is_fin0)
+         if (tc->rcv_nxt != vnet_buffer (b[0])->tcp.seq_number || is_fin)
            {
-             tcp_send_reset_w_pkt (tc0, b0, thread_index, is_ip4);
-             error0 = TCP_ERROR_SEGMENT_INVALID;
+             tcp_send_reset_w_pkt (tc, b[0], thread_index, is_ip4);
+             error = TCP_ERROR_SEGMENT_INVALID;
              goto drop;
            }
 
@@ -2192,47 +2214,47 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
           *  <SEQ=SEG.ACK><CTL=RST>
           * and send it.
           */
-         if (tcp_rcv_ack_no_cc (tc0, b0, &error0))
+         if (tcp_rcv_ack_no_cc (tc, b[0], &error))
            {
-             tcp_send_reset_w_pkt (tc0, b0, thread_index, is_ip4);
-             error0 = TCP_ERROR_SEGMENT_INVALID;
+             tcp_send_reset_w_pkt (tc, b[0], thread_index, is_ip4);
+             error = TCP_ERROR_SEGMENT_INVALID;
              goto drop;
            }
 
          /* Update rtt and rto */
-         tcp_estimate_initial_rtt (tc0);
-         tcp_connection_tx_pacer_update (tc0);
+         tcp_estimate_initial_rtt (tc);
+         tcp_connection_tx_pacer_update (tc);
 
          /* Switch state to ESTABLISHED */
-         tc0->state = TCP_STATE_ESTABLISHED;
-         TCP_EVT (TCP_EVT_STATE_CHANGE, tc0);
+         tc->state = TCP_STATE_ESTABLISHED;
+         TCP_EVT (TCP_EVT_STATE_CHANGE, tc);
 
-         if (!(tc0->cfg_flags & TCP_CFG_F_NO_TSO))
-           tcp_check_tx_offload (tc0, is_ip4);
+         if (!(tc->cfg_flags & TCP_CFG_F_NO_TSO))
+           tcp_check_tx_offload (tc, is_ip4);
 
          /* Initialize session variables */
-         tc0->snd_una = vnet_buffer (b0)->tcp.ack_number;
-         tc0->snd_wnd = clib_net_to_host_u16 (tcp0->window)
-           << tc0->rcv_opts.wscale;
-         tc0->snd_wl1 = vnet_buffer (b0)->tcp.seq_number;
-         tc0->snd_wl2 = vnet_buffer (b0)->tcp.ack_number;
+         tc->snd_una = vnet_buffer (b[0])->tcp.ack_number;
+         tc->snd_wnd = clib_net_to_host_u16 (tcp->window)
+                       << tc->rcv_opts.wscale;
+         tc->snd_wl1 = vnet_buffer (b[0])->tcp.seq_number;
+         tc->snd_wl2 = vnet_buffer (b[0])->tcp.ack_number;
 
          /* Reset SYN-ACK retransmit and SYN_RCV establish timers */
-         tcp_retransmit_timer_reset (&wrk->timer_wheel, tc0);
-         if (session_stream_accept_notify (&tc0->connection))
+         tcp_retransmit_timer_reset (&wrk->timer_wheel, tc);
+         if (session_stream_accept_notify (&tc->connection))
            {
-             error0 = TCP_ERROR_MSG_QUEUE_FULL;
-             tcp_send_reset (tc0);
-             session_transport_delete_notify (&tc0->connection);
-             tcp_connection_cleanup (tc0);
+             error = TCP_ERROR_MSG_QUEUE_FULL;
+             tcp_send_reset (tc);
+             session_transport_delete_notify (&tc->connection);
+             tcp_connection_cleanup (tc);
              goto drop;
            }
-         error0 = TCP_ERROR_ACK_OK;
+         error = TCP_ERROR_ACK_OK;
          break;
        case TCP_STATE_ESTABLISHED:
          /* We can get packets in established state here because they
           * were enqueued before state change */
-         if (tcp_rcv_ack (wrk, tc0, b0, tcp0, &error0))
+         if (tcp_rcv_ack (wrk, tc, b[0], tcp, &error))
            goto drop;
 
          break;
@@ -2240,93 +2262,93 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          /* In addition to the processing for the ESTABLISHED state, if
           * our FIN is now acknowledged then enter FIN-WAIT-2 and
           * continue processing in that state. */
-         if (tcp_rcv_ack (wrk, tc0, b0, tcp0, &error0))
+         if (tcp_rcv_ack (wrk, tc, b[0], tcp, &error))
            goto drop;
 
          /* Still have to send the FIN */
-         if (tc0->flags & TCP_CONN_FINPNDG)
+         if (tc->flags & TCP_CONN_FINPNDG)
            {
              /* TX fifo finally drained */
-             max_dequeue = transport_max_tx_dequeue (&tc0->connection);
-             if (max_dequeue <= tc0->burst_acked)
-               tcp_send_fin (tc0);
+             max_deq = transport_max_tx_dequeue (&tc->connection);
+             if (max_deq <= tc->burst_acked)
+               tcp_send_fin (tc);
              /* If a fin was received and data was acked extend wait */
-             else if ((tc0->flags & TCP_CONN_FINRCVD) && tc0->bytes_acked)
-               tcp_timer_update (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+             else if ((tc->flags & TCP_CONN_FINRCVD) && tc->bytes_acked)
+               tcp_timer_update (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                                  tcp_cfg.closewait_time);
            }
          /* If FIN is ACKed */
-         else if (tc0->snd_una == tc0->snd_nxt)
+         else if (tc->snd_una == tc->snd_nxt)
            {
              /* Stop all retransmit timers because we have nothing more
               * to send. */
-             tcp_connection_timers_reset (tc0);
+             tcp_connection_timers_reset (tc);
 
              /* We already have a FIN but didn't transition to CLOSING
               * because of outstanding tx data. Close the connection. */
-             if (tc0->flags & TCP_CONN_FINRCVD)
+             if (tc->flags & TCP_CONN_FINRCVD)
                {
-                 tcp_connection_set_state (tc0, TCP_STATE_CLOSED);
-                 session_transport_closed_notify (&tc0->connection);
-                 tcp_program_cleanup (wrk, tc0);
+                 tcp_connection_set_state (tc, TCP_STATE_CLOSED);
+                 session_transport_closed_notify (&tc->connection);
+                 tcp_program_cleanup (wrk, tc);
                  goto drop;
                }
 
-             tcp_connection_set_state (tc0, TCP_STATE_FIN_WAIT_2);
+             tcp_connection_set_state (tc, TCP_STATE_FIN_WAIT_2);
              /* Enable waitclose because we're willing to wait for peer's
               * FIN but not indefinitely. */
-             tcp_timer_set (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+             tcp_timer_set (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                             tcp_cfg.finwait2_time);
 
              /* Don't try to deq the FIN acked */
-             if (tc0->burst_acked > 1)
-               session_tx_fifo_dequeue_drop (&tc0->connection,
-                                             tc0->burst_acked - 1);
-             tc0->burst_acked = 0;
+             if (tc->burst_acked > 1)
+               session_tx_fifo_dequeue_drop (&tc->connection,
+                                             tc->burst_acked - 1);
+             tc->burst_acked = 0;
            }
          break;
        case TCP_STATE_FIN_WAIT_2:
          /* In addition to the processing for the ESTABLISHED state, if
           * the retransmission queue is empty, the user's CLOSE can be
           * acknowledged ("ok") but do not delete the TCB. */
-         if (tcp_rcv_ack_no_cc (tc0, b0, &error0))
+         if (tcp_rcv_ack_no_cc (tc, b[0], &error))
            goto drop;
-         tc0->burst_acked = 0;
+         tc->burst_acked = 0;
          break;
        case TCP_STATE_CLOSE_WAIT:
          /* Do the same processing as for the ESTABLISHED state. */
-         if (tcp_rcv_ack (wrk, tc0, b0, tcp0, &error0))
+         if (tcp_rcv_ack (wrk, tc, b[0], tcp, &error))
            goto drop;
 
-         if (!(tc0->flags & TCP_CONN_FINPNDG))
+         if (!(tc->flags & TCP_CONN_FINPNDG))
            break;
 
          /* Still have outstanding tx data */
-         max_dequeue = transport_max_tx_dequeue (&tc0->connection);
-         if (max_dequeue > tc0->burst_acked)
+         max_deq = transport_max_tx_dequeue (&tc->connection);
+         if (max_deq > tc->burst_acked)
            break;
 
-         tcp_send_fin (tc0);
-         tcp_connection_timers_reset (tc0);
-         tcp_connection_set_state (tc0, TCP_STATE_LAST_ACK);
-         tcp_timer_set (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+         tcp_send_fin (tc);
+         tcp_connection_timers_reset (tc);
+         tcp_connection_set_state (tc, TCP_STATE_LAST_ACK);
+         tcp_timer_set (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                         tcp_cfg.lastack_time);
          break;
        case TCP_STATE_CLOSING:
          /* In addition to the processing for the ESTABLISHED state, if
           * the ACK acknowledges our FIN then enter the TIME-WAIT state,
           * otherwise ignore the segment. */
-         if (tcp_rcv_ack_no_cc (tc0, b0, &error0))
+         if (tcp_rcv_ack_no_cc (tc, b[0], &error))
            goto drop;
 
-         if (tc0->snd_una != tc0->snd_nxt)
+         if (tc->snd_una != tc->snd_nxt)
            goto drop;
 
-         tcp_connection_timers_reset (tc0);
-         tcp_connection_set_state (tc0, TCP_STATE_TIME_WAIT);
-         tcp_timer_set (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+         tcp_connection_timers_reset (tc);
+         tcp_connection_set_state (tc, TCP_STATE_TIME_WAIT);
+         tcp_timer_set (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                         tcp_cfg.timewait_time);
-         session_transport_closed_notify (&tc0->connection);
+         session_transport_closed_notify (&tc->connection);
          goto drop;
 
          break;
@@ -2335,24 +2357,24 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
           * acknowledgment of our FIN. If our FIN is now acknowledged,
           * delete the TCB, enter the CLOSED state, and return. */
 
-         if (tcp_rcv_ack_no_cc (tc0, b0, &error0))
+         if (tcp_rcv_ack_no_cc (tc, b[0], &error))
            goto drop;
 
          /* Apparently our ACK for the peer's FIN was lost */
-         if (is_fin0 && tc0->snd_una != tc0->snd_nxt)
+         if (is_fin && tc->snd_una != tc->snd_nxt)
            {
-             tcp_send_fin (tc0);
+             tcp_send_fin (tc);
              goto drop;
            }
 
-         tcp_connection_set_state (tc0, TCP_STATE_CLOSED);
-         session_transport_closed_notify (&tc0->connection);
+         tcp_connection_set_state (tc, TCP_STATE_CLOSED);
+         session_transport_closed_notify (&tc->connection);
 
          /* Don't free the connection from the data path since
           * we can't ensure that we have no packets already enqueued
           * to output. Rely instead on the waitclose timer */
-         tcp_connection_timers_reset (tc0);
-         tcp_program_cleanup (tcp_get_worker (tc0->c_thread_index), tc0);
+         tcp_connection_timers_reset (tc);
+         tcp_program_cleanup (tcp_get_worker (tc->c_thread_index), tc);
 
          goto drop;
 
@@ -2362,14 +2384,14 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
           * retransmission of the remote FIN. Acknowledge it, and restart
           * the 2 MSL timeout. */
 
-         if (tcp_rcv_ack_no_cc (tc0, b0, &error0))
+         if (tcp_rcv_ack_no_cc (tc, b[0], &error))
            goto drop;
 
-         if (!is_fin0)
+         if (!is_fin)
            goto drop;
 
-         tcp_program_ack (tc0);
-         tcp_timer_update (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+         tcp_program_ack (tc);
+         tcp_timer_update (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                            tcp_cfg.timewait_time);
          goto drop;
 
@@ -2381,15 +2403,15 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
       /* 6: check the URG bit TODO */
 
       /* 7: process the segment text */
-      switch (tc0->state)
+      switch (tc->state)
        {
        case TCP_STATE_ESTABLISHED:
        case TCP_STATE_FIN_WAIT_1:
        case TCP_STATE_FIN_WAIT_2:
-         if (vnet_buffer (b0)->tcp.data_len)
-           error0 = tcp_segment_rcv (wrk, tc0, b0);
+         if (vnet_buffer (b[0])->tcp.data_len)
+           error = tcp_segment_rcv (wrk, tc, b[0]);
          /* Don't accept out of order fins lower */
-         if (vnet_buffer (b0)->tcp.seq_end != tc0->rcv_nxt)
+         if (vnet_buffer (b[0])->tcp.seq_end != tc->rcv_nxt)
            goto drop;
          break;
        case TCP_STATE_CLOSE_WAIT:
@@ -2402,31 +2424,31 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
        }
 
       /* 8: check the FIN bit */
-      if (!is_fin0)
+      if (!is_fin)
        goto drop;
 
-      TCP_EVT (TCP_EVT_FIN_RCVD, tc0);
+      TCP_EVT (TCP_EVT_FIN_RCVD, tc);
 
-      switch (tc0->state)
+      switch (tc->state)
        {
        case TCP_STATE_ESTABLISHED:
          /* Account for the FIN and send ack */
-         tc0->rcv_nxt += 1;
-         tcp_program_ack (tc0);
-         tcp_connection_set_state (tc0, TCP_STATE_CLOSE_WAIT);
-         tcp_program_disconnect (wrk, tc0);
-         tcp_timer_update (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+         tc->rcv_nxt += 1;
+         tcp_program_ack (tc);
+         tcp_connection_set_state (tc, TCP_STATE_CLOSE_WAIT);
+         tcp_program_disconnect (wrk, tc);
+         tcp_timer_update (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                            tcp_cfg.closewait_time);
          break;
        case TCP_STATE_SYN_RCVD:
          /* Send FIN-ACK, enter LAST-ACK and because the app was not
           * notified yet, set a cleanup timer instead of relying on
           * disconnect notify and the implicit close call. */
-         tcp_connection_timers_reset (tc0);
-         tc0->rcv_nxt += 1;
-         tcp_send_fin (tc0);
-         tcp_connection_set_state (tc0, TCP_STATE_LAST_ACK);
-         tcp_timer_set (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+         tcp_connection_timers_reset (tc);
+         tc->rcv_nxt += 1;
+         tcp_send_fin (tc);
+         tcp_connection_set_state (tc, TCP_STATE_LAST_ACK);
+         tcp_timer_set (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                         tcp_cfg.lastack_time);
          break;
        case TCP_STATE_CLOSE_WAIT:
@@ -2435,54 +2457,51 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          /* move along .. */
          break;
        case TCP_STATE_FIN_WAIT_1:
-         tc0->rcv_nxt += 1;
+         tc->rcv_nxt += 1;
 
-         if (tc0->flags & TCP_CONN_FINPNDG)
+         if (tc->flags & TCP_CONN_FINPNDG)
            {
              /* If data is outstanding, stay in FIN_WAIT_1 and try to finish
               * sending it. Since we already received a fin, do not wait
               * for too long. */
-             tc0->flags |= TCP_CONN_FINRCVD;
-             tcp_timer_update (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+             tc->flags |= TCP_CONN_FINRCVD;
+             tcp_timer_update (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                                tcp_cfg.closewait_time);
            }
          else
            {
-             tcp_connection_set_state (tc0, TCP_STATE_CLOSING);
-             tcp_program_ack (tc0);
+             tcp_connection_set_state (tc, TCP_STATE_CLOSING);
+             tcp_program_ack (tc);
              /* Wait for ACK for our FIN but not forever */
-             tcp_timer_update (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+             tcp_timer_update (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                                tcp_cfg.closing_time);
            }
          break;
        case TCP_STATE_FIN_WAIT_2:
          /* Got FIN, send ACK! Be more aggressive with resource cleanup */
-         tc0->rcv_nxt += 1;
-         tcp_connection_set_state (tc0, TCP_STATE_TIME_WAIT);
-         tcp_connection_timers_reset (tc0);
-         tcp_timer_set (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+         tc->rcv_nxt += 1;
+         tcp_connection_set_state (tc, TCP_STATE_TIME_WAIT);
+         tcp_connection_timers_reset (tc);
+         tcp_timer_set (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                         tcp_cfg.timewait_time);
-         tcp_program_ack (tc0);
-         session_transport_closed_notify (&tc0->connection);
+         tcp_program_ack (tc);
+         session_transport_closed_notify (&tc->connection);
          break;
        case TCP_STATE_TIME_WAIT:
          /* Remain in the TIME-WAIT state. Restart the time-wait
           * timeout.
           */
-         tcp_timer_update (&wrk->timer_wheel, tc0, TCP_TIMER_WAITCLOSE,
+         tcp_timer_update (&wrk->timer_wheel, tc, TCP_TIMER_WAITCLOSE,
                            tcp_cfg.timewait_time);
          break;
        }
-      error0 = TCP_ERROR_FIN_RCVD;
+      error = TCP_ERROR_FIN_RCVD;
 
     drop:
 
-      tcp_inc_counter (rcv_process, error0, 1);
-      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
-       {
-         tcp_rx_trace_t *t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
-         tcp_set_rx_trace_data (t0, tc0, tcp0, b0, is_ip4);
-       }
+      b += 1;
+      n_left_from -= 1;
+      tcp_inc_counter (rcv_process, error, 1);
     }
 
   errors = session_main_flush_enqueue_events (TRANSPORT_PROTO_TCP,
@@ -2490,9 +2509,9 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
   tcp_inc_counter (rcv_process, TCP_ERROR_MSG_QUEUE_FULL, errors);
   tcp_handle_postponed_dequeues (wrk);
   tcp_handle_disconnects (wrk);
-  vlib_buffer_free (vm, first_buffer, from_frame->n_vectors);
+  vlib_buffer_free (vm, from, frame->n_vectors);
 
-  return from_frame->n_vectors;
+  return frame->n_vectors;
 }
 
 VLIB_NODE_FN (tcp4_rcv_process_node) (vlib_main_t * vm,