X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvnet%2Ftcp%2Ftcp.c;h=b6c348288ece3811fe644de32759b312c4850b2e;hb=586afd762bfa149f5ca167bd5fd5a0cd59ce94fe;hp=0f9b7097b42d2f37eca7b424f64461186ed90b62;hpb=68b0fb0c620c7451ef1a6380c43c39de6614db51;p=vpp.git

diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index 0f9b7097b42..b6c348288ec 100644
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -21,7 +21,7 @@
 tcp_main_t tcp_main;
 
 static u32
-tcp_connection_bind (vlib_main_t * vm, u32 session_index, ip46_address_t * ip,
+tcp_connection_bind (u32 session_index, ip46_address_t * ip,
 		     u16 port_host_byte_order, u8 is_ip4)
 {
   tcp_main_t *tm = &tcp_main;
@@ -43,42 +43,41 @@ tcp_connection_bind (vlib_main_t * vm, u32 session_index, ip46_address_t * ip,
   listener->state = TCP_STATE_LISTEN;
   listener->c_is_ip4 = 1;
 
+  tcp_connection_timers_init (listener);
+
+  TCP_EVT_DBG (TCP_EVT_BIND, listener);
+
   return listener->c_c_index;
 }
 
 u32
-tcp_session_bind_ip4 (vlib_main_t * vm, u32 session_index,
-		      ip46_address_t * ip, u16 port_host_byte_order)
+tcp_session_bind_ip4 (u32 session_index, ip46_address_t * ip,
+		      u16 port_host_byte_order)
 {
-  return tcp_connection_bind (vm, session_index, ip, port_host_byte_order, 1);
+  return tcp_connection_bind (session_index, ip, port_host_byte_order, 1);
 }
 
 u32
-tcp_session_bind_ip6 (vlib_main_t * vm, u32 session_index,
-		      ip46_address_t * ip, u16 port_host_byte_order)
+tcp_session_bind_ip6 (u32 session_index, ip46_address_t * ip,
+		      u16 port_host_byte_order)
 {
-  return tcp_connection_bind (vm, session_index, ip, port_host_byte_order, 0);
+  return tcp_connection_bind (session_index, ip, port_host_byte_order, 0);
 
 }
 
 static void
-tcp_session_unbind (u32 listener_index)
+tcp_connection_unbind (u32 listener_index)
 {
   tcp_main_t *tm = vnet_get_tcp_main ();
+  TCP_EVT_DBG (TCP_EVT_UNBIND,
+	       pool_elt_at_index (tm->listener_pool, listener_index));
   pool_put_index (tm->listener_pool, listener_index);
 }
 
 u32
-tcp_session_unbind_ip4 (vlib_main_t * vm, u32 listener_index)
-{
-  tcp_session_unbind (listener_index);
-  return 0;
-}
-
-u32
-tcp_session_unbind_ip6 (vlib_main_t * vm, u32 listener_index)
+tcp_session_unbind (u32 listener_index)
 {
-  tcp_session_unbind (listener_index);
+  tcp_connection_unbind (listener_index);
   return 0;
 }
 
@@ -135,10 +134,25 @@ tcp_connection_cleanup (tcp_connection_t * tc)
 void
 tcp_connection_del (tcp_connection_t * tc)
 {
+  TCP_EVT_DBG (TCP_EVT_DELETE, tc);
   stream_session_delete_notify (&tc->connection);
   tcp_connection_cleanup (tc);
 }
 
+/** Notify session that connection has been reset.
+ *
+ * Switch state to closed and wait for session to call cleanup.
+ */
+void
+tcp_connection_reset (tcp_connection_t * tc)
+{
+  if (tc->state == TCP_STATE_CLOSED)
+    return;
+
+  tc->state = TCP_STATE_CLOSED;
+  stream_session_reset_notify (&tc->connection);
+}
+
 /**
  * Begin connection closing procedure.
  *
@@ -149,10 +163,14 @@ tcp_connection_del (tcp_connection_t * tc)
  * calls cleanup.
  * 2) TIME_WAIT (active close) whereby after 2MSL the 2MSL timer triggers
  * and cleanup is called.
+ *
+ * N.B. Half-close connections are not supported
  */
 void
 tcp_connection_close (tcp_connection_t * tc)
 {
+  TCP_EVT_DBG (TCP_EVT_CLOSE, tc);
+
   /* Send FIN if needed */
   if (tc->state == TCP_STATE_ESTABLISHED || tc->state == TCP_STATE_SYN_RCVD
       || tc->state == TCP_STATE_CLOSE_WAIT)
@@ -166,9 +184,9 @@ tcp_connection_close (tcp_connection_t * tc)
   else if (tc->state == TCP_STATE_CLOSE_WAIT)
     tc->state = TCP_STATE_LAST_ACK;
 
-  /* Half-close connections are not supported XXX */
-
-  if (tc->state == TCP_STATE_CLOSED)
+  /* If in CLOSED and WAITCLOSE timer is not set, delete connection now */
+  if (tc->timers[TCP_TIMER_WAITCLOSE] == TCP_TIMER_HANDLE_INVALID
+      && tc->state == TCP_STATE_CLOSED)
     tcp_connection_del (tc);
 }
 
@@ -185,7 +203,10 @@ tcp_session_cleanup (u32 conn_index, u32 thread_index)
 {
   tcp_connection_t *tc;
   tc = tcp_connection_get (conn_index, thread_index);
-  tcp_connection_cleanup (tc);
+
+  /* Wait for the session tx events to clear */
+  tc->state = TCP_STATE_CLOSED;
+  tcp_timer_update (tc, TCP_TIMER_WAITCLOSE, TCP_CLEANUP_TIME);
 }
 
 void *
@@ -217,6 +238,7 @@ ip_interface_get_first_ip (u32 sw_if_index, u8 is_ip4)
   return 0;
 }
 
+#define PORT_MASK ((1 << 16)- 1)
 /**
  * Allocate local port and add if successful add entry to local endpoint
  * table to mark the pair as used.
@@ -224,10 +246,10 @@ ip_interface_get_first_ip (u32 sw_if_index, u8 is_ip4)
 u16
 tcp_allocate_local_port (tcp_main_t * tm, ip46_address_t * ip)
 {
-  u8 unique = 0;
   transport_endpoint_t *tep;
   u32 time_now, tei;
-  u16 min = 1024, max = 65535, tries;	/* XXX configurable ? */
+  u16 min = 1024, max = 65535;	/* XXX configurable ? */
+  int tries;
 
   tries = max - min;
   time_now = tcp_time_now ();
@@ -235,37 +257,34 @@ tcp_allocate_local_port (tcp_main_t * tm, ip46_address_t * ip)
   /* Start at random point or max */
   pool_get (tm->local_endpoints, tep);
   clib_memcpy (&tep->ip, ip, sizeof (*ip));
-  tep->port = random_u32 (&time_now) << 16;
-  tep->port = tep->port < min ? max : tep->port;
 
   /* Search for first free slot */
-  while (tries)
+  for (; tries >= 0; tries--)
     {
+      u16 port = 0;
+
+      /* Find a port in the specified range */
+      while (1)
+	{
+	  port = random_u32 (&time_now) & PORT_MASK;
+	  if (PREDICT_TRUE (port >= min && port < max))
+	    break;
+	}
+
+      tep->port = port;
+
+      /* Look it up */
       tei = transport_endpoint_lookup (&tm->local_endpoints_table, &tep->ip,
 				       tep->port);
+      /* If not found, we're done */
       if (tei == TRANSPORT_ENDPOINT_INVALID_INDEX)
 	{
-	  unique = 1;
-	  break;
+	  transport_endpoint_table_add (&tm->local_endpoints_table, tep,
+					tep - tm->local_endpoints);
+	  return tep->port;
 	}
-
-      tep->port--;
-
-      if (tep->port < min)
-	tep->port = max;
-
-      tries--;
-    }
-
-  if (unique)
-    {
-      transport_endpoint_table_add (&tm->local_endpoints_table, tep,
-				    tep - tm->local_endpoints);
-
-      return tep->port;
     }
-
-  /* Failed */
+  /* No free ports */
   pool_put (tm->local_endpoints, tep);
   return -1;
 }
@@ -309,7 +328,7 @@ tcp_connection_init_vars (tcp_connection_t * tc)
 {
   tcp_connection_timers_init (tc);
   tcp_set_snd_mss (tc);
-  tc->sack_sb.head = TCP_INVALID_SACK_HOLE_INDEX;
+  scoreboard_init (&tc->sack_sb);
   tcp_cc_init (tc);
 }
 
@@ -360,7 +379,10 @@ tcp_connection_open (ip46_address_t * rmt_addr, u16 rmt_port, u8 is_ip4)
   /* Allocate source port */
   lcl_port = tcp_allocate_local_port (tm, &lcl_addr);
   if (lcl_port < 1)
-    return -1;
+    {
+      clib_warning ("Failed to allocate src port");
+      return -1;
+    }
 
   /*
    * Create connection and send SYN
@@ -383,6 +405,8 @@ tcp_connection_open (ip46_address_t * rmt_addr, u16 rmt_port, u8 is_ip4)
 
   tc->state = TCP_STATE_SYN_SENT;
 
+  TCP_EVT_DBG (TCP_EVT_OPEN, tc);
+
   return tc->c_c_index;
 }
 
@@ -398,82 +422,119 @@ tcp_session_open_ip6 (ip46_address_t * addr, u16 port)
   return tcp_connection_open (addr, port, 0);
 }
 
+const char *tcp_dbg_evt_str[] = {
+#define _(sym, str) str,
+  foreach_tcp_dbg_evt
+#undef _
+};
+
+const char *tcp_fsm_states[] = {
+#define _(sym, str) str,
+  foreach_tcp_fsm_state
+#undef _
+};
+
 u8 *
-format_tcp_session_ip4 (u8 * s, va_list * args)
+format_tcp_state (u8 * s, va_list * args)
 {
-  u32 tci = va_arg (*args, u32);
-  u32 thread_index = va_arg (*args, u32);
-  tcp_connection_t *tc;
+  tcp_state_t *state = va_arg (*args, tcp_state_t *);
 
-  tc = tcp_connection_get (tci, thread_index);
+  if (*state < TCP_N_STATES)
+    s = format (s, "%s", tcp_fsm_states[*state]);
+  else
+    s = format (s, "UNKNOWN");
 
-  s = format (s, "[%s] %U:%d->%U:%d", "tcp", format_ip4_address,
-	      &tc->c_lcl_ip4, clib_net_to_host_u16 (tc->c_lcl_port),
-	      format_ip4_address, &tc->c_rmt_ip4,
-	      clib_net_to_host_u16 (tc->c_rmt_port));
+  return s;
+}
+
+const char *tcp_conn_timers[] = {
+#define _(sym, str) str,
+  foreach_tcp_timer
+#undef _
+};
+
+u8 *
+format_tcp_timers (u8 * s, va_list * args)
+{
+  tcp_connection_t *tc = va_arg (*args, tcp_connection_t *);
+  int i, last = 0;
+
+  for (i = 0; i < TCP_N_TIMERS; i++)
+    if (tc->timers[i] != TCP_TIMER_HANDLE_INVALID)
+      last = i;
+
+  s = format (s, "[");
+  for (i = 0; i < last; i++)
+    {
+      if (tc->timers[i] != TCP_TIMER_HANDLE_INVALID)
+	s = format (s, "%s,", tcp_conn_timers[i]);
+    }
+
+  if (last > 0)
+    s = format (s, "%s]", tcp_conn_timers[i]);
+  else
+    s = format (s, "]");
 
   return s;
 }
 
 u8 *
-format_tcp_session_ip6 (u8 * s, va_list * args)
+format_tcp_connection (u8 * s, va_list * args)
 {
-  u32 tci = va_arg (*args, u32);
-  u32 thread_index = va_arg (*args, u32);
-  tcp_connection_t *tc = tcp_connection_get (tci, thread_index);
-  s = format (s, "[%s] %U:%d->%U:%d", "tcp", format_ip6_address,
-	      &tc->c_lcl_ip6, clib_net_to_host_u16 (tc->c_lcl_port),
-	      format_ip6_address, &tc->c_rmt_ip6,
-	      clib_net_to_host_u16 (tc->c_rmt_port));
+  tcp_connection_t *tc = va_arg (*args, tcp_connection_t *);
+
+  if (tc->c_is_ip4)
+    {
+      s = format (s, "[#%d][%s] %U:%d->%U:%d", tc->c_thread_index, "T",
+		  format_ip4_address, &tc->c_lcl_ip4,
+		  clib_net_to_host_u16 (tc->c_lcl_port), format_ip4_address,
+		  &tc->c_rmt_ip4, clib_net_to_host_u16 (tc->c_rmt_port));
+    }
+  else
+    {
+      s = format (s, "[#%d][%s] %U:%d->%U:%d", tc->c_thread_index, "T",
+		  format_ip6_address, &tc->c_lcl_ip6,
+		  clib_net_to_host_u16 (tc->c_lcl_port), format_ip6_address,
+		  &tc->c_rmt_ip6, clib_net_to_host_u16 (tc->c_rmt_port));
+    }
+
   return s;
 }
 
 u8 *
-format_tcp_listener_session_ip4 (u8 * s, va_list * args)
+format_tcp_connection_verbose (u8 * s, va_list * args)
 {
-  u32 tci = va_arg (*args, u32);
-  tcp_connection_t *tc = tcp_listener_get (tci);
-  s = format (s, "[%s] %U:%d->%U:%d", "tcp", format_ip4_address,
-	      &tc->c_lcl_ip4, clib_net_to_host_u16 (tc->c_lcl_port),
-	      format_ip4_address, &tc->c_rmt_ip4,
-	      clib_net_to_host_u16 (tc->c_rmt_port));
+  tcp_connection_t *tc = va_arg (*args, tcp_connection_t *);
+  s = format (s, "%U %U %U", format_tcp_connection, tc, format_tcp_state,
+	      &tc->state, format_tcp_timers, tc);
   return s;
 }
 
 u8 *
-format_tcp_listener_session_ip6 (u8 * s, va_list * args)
+format_tcp_session (u8 * s, va_list * args)
 {
   u32 tci = va_arg (*args, u32);
-  tcp_connection_t *tc = tcp_listener_get (tci);
-  s = format (s, "[%s] %U:%d->%U:%d", "tcp", format_ip6_address,
-	      &tc->c_lcl_ip6, clib_net_to_host_u16 (tc->c_lcl_port),
-	      format_ip6_address, &tc->c_rmt_ip6,
-	      clib_net_to_host_u16 (tc->c_rmt_port));
-  return s;
+  u32 thread_index = va_arg (*args, u32);
+  tcp_connection_t *tc;
+
+  tc = tcp_connection_get (tci, thread_index);
+  return format (s, "%U", format_tcp_connection, tc);
 }
 
 u8 *
-format_tcp_half_open_session_ip4 (u8 * s, va_list * args)
+format_tcp_listener_session (u8 * s, va_list * args)
 {
   u32 tci = va_arg (*args, u32);
-  tcp_connection_t *tc = tcp_half_open_connection_get (tci);
-  s = format (s, "[%s] %U:%d->%U:%d", "tcp", format_ip4_address,
-	      &tc->c_lcl_ip4, clib_net_to_host_u16 (tc->c_lcl_port),
-	      format_ip4_address, &tc->c_rmt_ip4,
-	      clib_net_to_host_u16 (tc->c_rmt_port));
-  return s;
+  tcp_connection_t *tc = tcp_listener_get (tci);
+  return format (s, "%U", format_tcp_connection, tc);
 }
 
 u8 *
-format_tcp_half_open_session_ip6 (u8 * s, va_list * args)
+format_tcp_half_open_session (u8 * s, va_list * args)
 {
   u32 tci = va_arg (*args, u32);
   tcp_connection_t *tc = tcp_half_open_connection_get (tci);
-  s = format (s, "[%s] %U:%d->%U:%d", "tcp", format_ip6_address,
-	      &tc->c_lcl_ip6, clib_net_to_host_u16 (tc->c_lcl_port),
-	      format_ip6_address, &tc->c_rmt_ip6,
-	      clib_net_to_host_u16 (tc->c_rmt_port));
-  return s;
+  return format (s, "%U", format_tcp_connection, tc);
 }
 
 transport_connection_t *
@@ -497,24 +558,57 @@ tcp_session_send_mss (transport_connection_t * trans_conn)
   return tc->snd_mss;
 }
 
+/**
+ * Compute tx window session is allowed to fill.
+ */
 u32
 tcp_session_send_space (transport_connection_t * trans_conn)
 {
+  u32 snd_space;
   tcp_connection_t *tc = (tcp_connection_t *) trans_conn;
-  return tcp_available_snd_space (tc);
+
+  /* If we haven't gotten dupacks or if we did and have gotten sacked bytes
+   * then we can still send */
+  if (PREDICT_TRUE (tcp_in_fastrecovery (tc) == 0
+		    && (tc->rcv_dupacks == 0
+			|| tc->sack_sb.last_sacked_bytes)))
+    {
+      snd_space = tcp_available_snd_space (tc);
+
+      /* If we can't write at least a segment, don't try at all */
+      if (snd_space < tc->snd_mss)
+	return 0;
+
+      /* round down to mss multiple */
+      return snd_space - (snd_space % tc->snd_mss);
+    }
+
+  /* If in fast recovery, send 1 SMSS if wnd allows */
+  if (tcp_in_fastrecovery (tc) && tcp_available_snd_space (tc)
+      && tcp_fastrecovery_sent_1_smss (tc))
+    {
+      tcp_fastrecovery_1_smss_on (tc);
+      return tc->snd_mss;
+    }
+
+  return 0;
 }
 
 u32
-tcp_session_rx_fifo_offset (transport_connection_t * trans_conn)
+tcp_session_tx_fifo_offset (transport_connection_t * trans_conn)
 {
   tcp_connection_t *tc = (tcp_connection_t *) trans_conn;
-  return (tc->snd_una_max - tc->snd_una);
+
+  ASSERT (seq_geq (tc->snd_nxt, tc->snd_una));
+
+  /* This still works if fast retransmit is on */
+  return (tc->snd_nxt - tc->snd_una);
 }
 
 /* *INDENT-OFF* */
 const static transport_proto_vft_t tcp4_proto = {
   .bind = tcp_session_bind_ip4,
-  .unbind = tcp_session_unbind_ip4,
+  .unbind = tcp_session_unbind,
   .push_header = tcp_push_header,
   .get_connection = tcp_session_get_transport,
   .get_listener = tcp_session_get_listener,
@@ -524,15 +618,15 @@ const static transport_proto_vft_t tcp4_proto = {
   .cleanup = tcp_session_cleanup,
   .send_mss = tcp_session_send_mss,
   .send_space = tcp_session_send_space,
-  .rx_fifo_offset = tcp_session_rx_fifo_offset,
-  .format_connection = format_tcp_session_ip4,
-  .format_listener = format_tcp_listener_session_ip4,
-  .format_half_open = format_tcp_half_open_session_ip4
+  .tx_fifo_offset = tcp_session_tx_fifo_offset,
+  .format_connection = format_tcp_session,
+  .format_listener = format_tcp_listener_session,
+  .format_half_open = format_tcp_half_open_session,
 };
 
 const static transport_proto_vft_t tcp6_proto = {
   .bind = tcp_session_bind_ip6,
-  .unbind = tcp_session_unbind_ip6,
+  .unbind = tcp_session_unbind,
   .push_header = tcp_push_header,
   .get_connection = tcp_session_get_transport,
   .get_listener = tcp_session_get_listener,
@@ -542,20 +636,20 @@ const static transport_proto_vft_t tcp6_proto = {
   .cleanup = tcp_session_cleanup,
   .send_mss = tcp_session_send_mss,
   .send_space = tcp_session_send_space,
-  .rx_fifo_offset = tcp_session_rx_fifo_offset,
-  .format_connection = format_tcp_session_ip6,
-  .format_listener = format_tcp_listener_session_ip6,
-  .format_half_open = format_tcp_half_open_session_ip6
+  .tx_fifo_offset = tcp_session_tx_fifo_offset,
+  .format_connection = format_tcp_session,
+  .format_listener = format_tcp_listener_session,
+  .format_half_open = format_tcp_half_open_session,
 };
 /* *INDENT-ON* */
 
 void
 tcp_timer_keep_handler (u32 conn_index)
 {
-  u32 cpu_index = os_get_cpu_number ();
+  u32 thread_index = vlib_get_thread_index ();
   tcp_connection_t *tc;
 
-  tc = tcp_connection_get (conn_index, cpu_index);
+  tc = tcp_connection_get (conn_index, thread_index);
   tc->timers[TCP_TIMER_KEEP] = TCP_TIMER_HANDLE_INVALID;
 
   tcp_connection_close (tc);
@@ -579,13 +673,32 @@ tcp_timer_establish_handler (u32 conn_index)
 }
 
 void
-tcp_timer_2msl_handler (u32 conn_index)
+tcp_timer_waitclose_handler (u32 conn_index)
 {
-  u32 cpu_index = os_get_cpu_number ();
+  u32 thread_index = vlib_get_thread_index ();
   tcp_connection_t *tc;
 
-  tc = tcp_connection_get (conn_index, cpu_index);
-  tc->timers[TCP_TIMER_2MSL] = TCP_TIMER_HANDLE_INVALID;
+  tc = tcp_connection_get (conn_index, thread_index);
+  tc->timers[TCP_TIMER_WAITCLOSE] = TCP_TIMER_HANDLE_INVALID;
+
+  /* Session didn't come back with a close(). Send FIN either way
+   * and switch to LAST_ACK. */
+  if (tc->state == TCP_STATE_CLOSE_WAIT)
+    {
+      if (tc->flags & TCP_CONN_FINSNT)
+	{
+	  clib_warning ("FIN was sent and still in CLOSE WAIT. Weird!");
+	}
+
+      tcp_send_fin (tc);
+      tc->state = TCP_STATE_LAST_ACK;
+
+      /* Make sure we don't wait in LAST ACK forever */
+      tcp_timer_set (tc, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME);
+
+      /* Don't delete the connection yet */
+      return;
+    }
 
   tcp_connection_del (tc);
 }
@@ -595,9 +708,9 @@ static timer_expiration_handler *timer_expiration_handlers[TCP_N_TIMERS] =
 {
     tcp_timer_retransmit_handler,
     tcp_timer_delack_handler,
-    0,
+    tcp_timer_persist_handler,
     tcp_timer_keep_handler,
-    tcp_timer_2msl_handler,
+    tcp_timer_waitclose_handler,
     tcp_timer_retransmit_syn_handler,
     tcp_timer_establish_handler
 };
@@ -615,6 +728,8 @@ tcp_expired_timers_dispatch (u32 * expired_timers)
       connection_index = expired_timers[i] & 0x0FFFFFFF;
       timer_id = expired_timers[i] >> 28;
 
+      TCP_EVT_DBG (TCP_EVT_TIMER_POP, connection_index, timer_id);
+
       /* Handle expiration */
       (*timer_expiration_handlers[timer_id]) (connection_index);
     }
@@ -633,18 +748,15 @@ tcp_initialize_timer_wheels (tcp_main_t * tm)
 }
 
 clib_error_t *
-tcp_init (vlib_main_t * vm)
+tcp_main_enable (vlib_main_t * vm)
 {
-  ip_main_t *im = &ip_main;
-  ip_protocol_info_t *pi;
   tcp_main_t *tm = vnet_get_tcp_main ();
+  ip_protocol_info_t *pi;
+  ip_main_t *im = &ip_main;
   vlib_thread_main_t *vtm = vlib_get_thread_main ();
   clib_error_t *error = 0;
   u32 num_threads;
 
-  tm->vlib_main = vm;
-  tm->vnet_main = vnet_get_main ();
-
   if ((error = vlib_call_init_function (vm, ip_main_init)))
     return error;
   if ((error = vlib_call_init_function (vm, ip4_lookup_init)))
@@ -683,7 +795,7 @@ tcp_init (vlib_main_t * vm)
   vec_validate (tm->timer_wheels, num_threads - 1);
   tcp_initialize_timer_wheels (tm);
 
-  vec_validate (tm->delack_connections, num_threads - 1);
+//  vec_validate (tm->delack_connections, num_threads - 1);
 
   /* Initialize clocks per tick for TCP timestamp. Used to compute
    * monotonically increasing timestamps. */
@@ -697,6 +809,36 @@ tcp_init (vlib_main_t * vm)
   return error;
 }
 
+clib_error_t *
+vnet_tcp_enable_disable (vlib_main_t * vm, u8 is_en)
+{
+  if (is_en)
+    {
+      if (tcp_main.is_enabled)
+	return 0;
+
+      return tcp_main_enable (vm);
+    }
+  else
+    {
+      tcp_main.is_enabled = 0;
+    }
+
+  return 0;
+}
+
+clib_error_t *
+tcp_init (vlib_main_t * vm)
+{
+  tcp_main_t *tm = vnet_get_tcp_main ();
+
+  tm->vlib_main = vm;
+  tm->vnet_main = vnet_get_main ();
+  tm->is_enabled = 0;
+
+  return 0;
+}
+
 VLIB_INIT_FUNCTION (tcp_init);
 
 /*