src/vnet/udp/udp.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2016-2020 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <vnet/udp/udp.h>
 #include <vnet/session/session.h>
 #include <vnet/dpo/load_balance.h>
 #include <vnet/ip/ip4_inlines.h>
 #include <vnet/ip/ip6_inlines.h>
 #include <vppinfra/sparse_vec.h>

 udp_main_t udp_main;

 static void
 udp_connection_register_port (vlib_main_t * vm, u16 lcl_port, u8 is_ip4)
 {
   udp_main_t *um = &udp_main;
   udp_dst_port_info_t *pi;
   u16 *n;

   pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
   if (!pi)
     {
       udp_add_dst_port (um, lcl_port, 0, is_ip4);
       pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
       pi->n_connections = 1;
     }
   else
     {
       pi->n_connections += 1;
       /* Do not return. The fact that the pi is valid does not mean
        * it's up to date */
     }

   pi->node_index = is_ip4 ? udp4_input_node.index : udp6_input_node.index;
   pi->next_index = um->local_to_input_edge[is_ip4];

   /* Setup udp protocol -> next index sparse vector mapping. */
   if (is_ip4)
     n = sparse_vec_validate (um->next_by_dst_port4,
 			     clib_host_to_net_u16 (lcl_port));
   else
     n = sparse_vec_validate (um->next_by_dst_port6,
 			     clib_host_to_net_u16 (lcl_port));

   n[0] = pi->next_index;
 }

 static void
 udp_connection_unregister_port (u16 lcl_port, u8 is_ip4)
 {
   udp_main_t *um = &udp_main;
   udp_dst_port_info_t *pi;

   pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
   if (!pi)
     return;

   if (!pi->n_connections)
     {
       clib_warning ("no connections using port %u", lcl_port);
       return;
     }

   if (!clib_atomic_sub_fetch (&pi->n_connections, 1))
     udp_unregister_dst_port (0, lcl_port, is_ip4);
 }

 void
 udp_connection_share_port (u16 lcl_port, u8 is_ip4)
 {
   udp_main_t *um = &udp_main;
   udp_dst_port_info_t *pi;

   /* Done without a lock but the operation is atomic. Writers to pi hash
    * table and vector should be guarded by a barrier sync */
   pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
   clib_atomic_fetch_add_rel (&pi->n_connections, 1);
 }

 udp_connection_t *
 udp_connection_alloc (u32 thread_index)
 {
   udp_main_t *um = &udp_main;
   udp_connection_t *uc;
   u32 will_expand = 0;
   pool_get_aligned_will_expand (um->connections[thread_index], will_expand,
 				CLIB_CACHE_LINE_BYTES);

   if (PREDICT_FALSE (will_expand))
     {
       clib_spinlock_lock_if_init (&udp_main.peekers_write_locks
 				  [thread_index]);
       pool_get_aligned (udp_main.connections[thread_index], uc,
 			CLIB_CACHE_LINE_BYTES);
       clib_spinlock_unlock_if_init (&udp_main.peekers_write_locks
 				    [thread_index]);
     }
   else
     {
       pool_get_aligned (um->connections[thread_index], uc,
 			CLIB_CACHE_LINE_BYTES);
     }
   clib_memset (uc, 0, sizeof (*uc));
   uc->c_c_index = uc - um->connections[thread_index];
   uc->c_thread_index = thread_index;
   uc->c_proto = TRANSPORT_PROTO_UDP;
   return uc;
 }

 void
 udp_connection_free (udp_connection_t * uc)
 {
   u32 thread_index = uc->c_thread_index;
   clib_spinlock_free (&uc->rx_lock);
   if (CLIB_DEBUG)
     clib_memset (uc, 0xFA, sizeof (*uc));
   pool_put (udp_main.connections[thread_index], uc);
 }

 static void
 udp_connection_cleanup (udp_connection_t * uc)
 {
   transport_endpoint_cleanup (TRANSPORT_PROTO_UDP, &uc->c_lcl_ip,
 			      uc->c_lcl_port);
   udp_connection_unregister_port (clib_net_to_host_u16 (uc->c_lcl_port),
 				  uc->c_is_ip4);
   udp_connection_free (uc);
 }

 void
 udp_connection_delete (udp_connection_t * uc)
 {
   session_transport_delete_notify (&uc->connection);
   udp_connection_cleanup (uc);
 }

 static u8
 udp_connection_port_used_extern (u16 lcl_port, u8 is_ip4)
 {
   udp_main_t *um = vnet_get_udp_main ();
   udp_dst_port_info_t *pi;

   pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
   return (pi && !pi->n_connections
 	  && udp_is_valid_dst_port (lcl_port, is_ip4));
 }

 static u16
 udp_default_mtu (udp_main_t * um, u8 is_ip4)
 {
   u16 ip_hlen = is_ip4 ? sizeof (ip4_header_t) : sizeof (ip6_header_t);
   return (um->default_mtu - sizeof (udp_header_t) - ip_hlen);
 }

 static u32
 udp_session_bind (u32 session_index, transport_endpoint_t * lcl)
 {
   udp_main_t *um = vnet_get_udp_main ();
   vlib_main_t *vm = vlib_get_main ();
   transport_endpoint_cfg_t *lcl_ext;
   udp_connection_t *listener;
   u16 lcl_port_ho;
   void *iface_ip;

   lcl_port_ho = clib_net_to_host_u16 (lcl->port);

   if (udp_connection_port_used_extern (lcl_port_ho, lcl->is_ip4))
     {
       clib_warning ("port already used");
       return SESSION_E_PORTINUSE;
     }

   pool_get (um->listener_pool, listener);
   clib_memset (listener, 0, sizeof (udp_connection_t));

   listener->c_lcl_port = lcl->port;
   listener->c_c_index = listener - um->listener_pool;

   /* If we are provided a sw_if_index, bind using one of its ips */
   if (ip_is_zero (&lcl->ip, 1) && lcl->sw_if_index != ENDPOINT_INVALID_INDEX)
     {
       if ((iface_ip = ip_interface_get_first_ip (lcl->sw_if_index,
 						 lcl->is_ip4)))
 	ip_set (&lcl->ip, iface_ip, lcl->is_ip4);
     }
   ip_copy (&listener->c_lcl_ip, &lcl->ip, lcl->is_ip4);
   listener->c_is_ip4 = lcl->is_ip4;
   listener->c_proto = TRANSPORT_PROTO_UDP;
   listener->c_s_index = session_index;
   listener->c_fib_index = lcl->fib_index;
   listener->mss = udp_default_mtu (um, listener->c_is_ip4);
   listener->flags |= UDP_CONN_F_OWNS_PORT | UDP_CONN_F_LISTEN;
   lcl_ext = (transport_endpoint_cfg_t *) lcl;
   if (lcl_ext->transport_flags & TRANSPORT_CFG_F_CONNECTED)
     listener->flags |= UDP_CONN_F_CONNECTED;
   else
     listener->c_flags |= TRANSPORT_CONNECTION_F_CLESS;
   clib_spinlock_init (&listener->rx_lock);

   udp_connection_register_port (vm, lcl_port_ho, lcl->is_ip4);
   return listener->c_c_index;
 }

 static u32
 udp_session_unbind (u32 listener_index)
 {
   udp_main_t *um = &udp_main;
   udp_connection_t *listener;

   listener = udp_listener_get (listener_index);
   udp_connection_unregister_port (clib_net_to_host_u16 (listener->c_lcl_port),
 				  listener->c_is_ip4);
   clib_spinlock_free (&listener->rx_lock);
   pool_put (um->listener_pool, listener);
   return 0;
 }

 static transport_connection_t *
 udp_session_get_listener (u32 listener_index)
 {
   udp_connection_t *us;

   us = udp_listener_get (listener_index);
   return &us->connection;
 }

 static u32
 udp_push_header (transport_connection_t * tc, vlib_buffer_t * b)
 {
   udp_connection_t *uc;
   vlib_main_t *vm = vlib_get_main ();

   uc = udp_connection_from_transport (tc);

   vlib_buffer_push_udp (b, uc->c_lcl_port, uc->c_rmt_port, 1);
   if (tc->is_ip4)
     vlib_buffer_push_ip4_custom (vm, b, &uc->c_lcl_ip4, &uc->c_rmt_ip4,
 				 IP_PROTOCOL_UDP, 1 /* csum offload */,
 				 0 /* is_df */, uc->c_dscp);
   else
     vlib_buffer_push_ip6 (vm, b, &uc->c_lcl_ip6, &uc->c_rmt_ip6,
 			  IP_PROTOCOL_UDP);
   vnet_buffer (b)->sw_if_index[VLIB_RX] = 0;
   vnet_buffer (b)->sw_if_index[VLIB_TX] = uc->c_fib_index;
   b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;

   if (PREDICT_FALSE (uc->flags & UDP_CONN_F_CLOSING))
     {
       if (!transport_max_tx_dequeue (&uc->connection))
 	udp_connection_delete (uc);
     }

   return 0;
 }

 static transport_connection_t *
 udp_session_get (u32 connection_index, u32 thread_index)
 {
   udp_connection_t *uc;
   uc = udp_connection_get (connection_index, thread_index);
   if (uc)
     return &uc->connection;
   return 0;
 }

 static void
 udp_session_close (u32 connection_index, u32 thread_index)
 {
   udp_connection_t *uc;

   uc = udp_connection_get (connection_index, thread_index);
   if (!uc)
     return;

   if (!transport_max_tx_dequeue (&uc->connection))
     udp_connection_delete (uc);
   else
     uc->flags |= UDP_CONN_F_CLOSING;
 }

 static void
 udp_session_cleanup (u32 connection_index, u32 thread_index)
 {
   udp_connection_t *uc;
   uc = udp_connection_get (connection_index, thread_index);
   if (!uc)
     return;
   if (uc->flags & UDP_CONN_F_MIGRATED)
     udp_connection_free (uc);
   else
     udp_connection_cleanup (uc);
 }

 static int
 udp_session_send_params (transport_connection_t * tconn,
 			 transport_send_params_t * sp)
 {
   udp_connection_t *uc;

   uc = udp_connection_from_transport (tconn);

   /* No constraint on TX window */
   sp->snd_space = ~0;
   /* TODO figure out MTU of output interface */
   sp->snd_mss = uc->mss;
   sp->tx_offset = 0;
   sp->flags = 0;
   return 0;
 }

 static int
 udp_open_connection (transport_endpoint_cfg_t * rmt)
 {
   vlib_main_t *vm = vlib_get_main ();
   u32 thread_index = vm->thread_index;
   udp_main_t *um = &udp_main;
   ip46_address_t lcl_addr;
   udp_connection_t *uc;
   u16 lcl_port;
   int rv;

   rv = transport_alloc_local_endpoint (TRANSPORT_PROTO_UDP, rmt, &lcl_addr,
 				       &lcl_port);
   if (rv)
     {
       if (rv != SESSION_E_PORTINUSE)
 	return rv;

       if (udp_connection_port_used_extern (lcl_port, rmt->is_ip4))
 	return SESSION_E_PORTINUSE;

       /* If port in use, check if 5-tuple is also in use */
       if (session_lookup_connection (rmt->fib_index, &lcl_addr, &rmt->ip,
 				     lcl_port, rmt->port, TRANSPORT_PROTO_UDP,
 				     rmt->is_ip4))
 	return SESSION_E_PORTINUSE;

       /* 5-tuple is available so increase lcl endpoint refcount and proceed
        * with connection allocation */
       transport_share_local_endpoint (TRANSPORT_PROTO_UDP, &lcl_addr,
 				      lcl_port);
       goto conn_alloc;
     }

   if (udp_is_valid_dst_port (lcl_port, rmt->is_ip4))
     {
       /* If specific source port was requested abort */
       if (rmt->peer.port)
 	return SESSION_E_PORTINUSE;

       /* Try to find a port that's not used */
       while (udp_is_valid_dst_port (lcl_port, rmt->is_ip4))
 	{
 	  lcl_port = transport_alloc_local_port (TRANSPORT_PROTO_UDP,
 						 &lcl_addr);
 	  if (lcl_port < 1)
 	    return SESSION_E_PORTINUSE;
 	}
     }

 conn_alloc:

   udp_connection_register_port (vm, lcl_port, rmt->is_ip4);

   /* We don't poll main thread if we have workers */
   thread_index = transport_cl_thread ();

   uc = udp_connection_alloc (thread_index);
   ip_copy (&uc->c_rmt_ip, &rmt->ip, rmt->is_ip4);
   ip_copy (&uc->c_lcl_ip, &lcl_addr, rmt->is_ip4);
   uc->c_rmt_port = rmt->port;
   uc->c_lcl_port = clib_host_to_net_u16 (lcl_port);
   uc->c_is_ip4 = rmt->is_ip4;
   uc->c_proto = TRANSPORT_PROTO_UDP;
   uc->c_fib_index = rmt->fib_index;
   uc->c_dscp = rmt->dscp;
   uc->mss = rmt->mss ? rmt->mss : udp_default_mtu (um, uc->c_is_ip4);
   uc->flags |= UDP_CONN_F_OWNS_PORT;
   if (rmt->transport_flags & TRANSPORT_CFG_F_CONNECTED)
     {
       uc->flags |= UDP_CONN_F_CONNECTED;
     }
   else
     {
       clib_spinlock_init (&uc->rx_lock);
       uc->c_flags |= TRANSPORT_CONNECTION_F_CLESS;
     }

   return uc->c_c_index;
 }

 static transport_connection_t *
 udp_session_get_half_open (u32 conn_index)
 {
   udp_connection_t *uc;
   u32 thread_index;

   /* We don't poll main thread if we have workers */
   thread_index = transport_cl_thread ();
   uc = udp_connection_get (conn_index, thread_index);
   if (!uc)
     return 0;
   return &uc->connection;
 }

 static u8 *
 format_udp_session (u8 * s, va_list * args)
 {
   u32 uci = va_arg (*args, u32);
   u32 thread_index = va_arg (*args, u32);
   u32 verbose = va_arg (*args, u32);
   udp_connection_t *uc;

   uc = udp_connection_get (uci, thread_index);
   return format (s, "%U", format_udp_connection, uc, verbose);
 }

 static u8 *
 format_udp_half_open_session (u8 * s, va_list * args)
 {
   u32 __clib_unused tci = va_arg (*args, u32);
   u32 __clib_unused thread_index = va_arg (*args, u32);
   clib_warning ("BUG");
   return 0;
 }

 static u8 *
 format_udp_listener_session (u8 * s, va_list * args)
 {
   u32 tci = va_arg (*args, u32);
   u32 __clib_unused thread_index = va_arg (*args, u32);
   u32 verbose = va_arg (*args, u32);
   udp_connection_t *uc = udp_listener_get (tci);
   return format (s, "%U", format_udp_connection, uc, verbose);
 }

 /* *INDENT-OFF* */
 static const transport_proto_vft_t udp_proto = {
   .start_listen = udp_session_bind,
   .connect = udp_open_connection,
   .stop_listen = udp_session_unbind,
   .push_header = udp_push_header,
   .get_connection = udp_session_get,
   .get_listener = udp_session_get_listener,
   .get_half_open = udp_session_get_half_open,
   .close = udp_session_close,
   .cleanup = udp_session_cleanup,
   .send_params = udp_session_send_params,
   .format_connection = format_udp_session,
   .format_half_open = format_udp_half_open_session,
   .format_listener = format_udp_listener_session,
   .transport_options = {
     .name = "udp",
     .short_name = "U",
     .tx_type = TRANSPORT_TX_DGRAM,
     .service_type = TRANSPORT_SERVICE_CL,
   },
 };
 /* *INDENT-ON* */

 static clib_error_t *
 udp_init (vlib_main_t * vm)
 {
   udp_main_t *um = vnet_get_udp_main ();
   ip_main_t *im = &ip_main;
   vlib_thread_main_t *tm = vlib_get_thread_main ();
   u32 num_threads;
   ip_protocol_info_t *pi;
   int i;

   /*
    * Registrations
    */

   /* IP registration */
   pi = ip_get_protocol_info (im, IP_PROTOCOL_UDP);
   if (pi == 0)
     return clib_error_return (0, "UDP protocol info AWOL");
   pi->format_header = format_udp_header;
   pi->unformat_pg_edit = unformat_pg_udp_header;

   /* Register as transport with URI */
   transport_register_protocol (TRANSPORT_PROTO_UDP, &udp_proto,
 			       FIB_PROTOCOL_IP4, ip4_lookup_node.index);
   transport_register_protocol (TRANSPORT_PROTO_UDP, &udp_proto,
 			       FIB_PROTOCOL_IP6, ip6_lookup_node.index);

   /*
    * Initialize data structures
    */

   num_threads = 1 /* main thread */  + tm->n_threads;
   vec_validate (um->connections, num_threads - 1);
   vec_validate (um->connection_peekers, num_threads - 1);
   vec_validate (um->peekers_readers_locks, num_threads - 1);
   vec_validate (um->peekers_write_locks, num_threads - 1);

   if (num_threads > 1)
     for (i = 0; i < num_threads; i++)
       {
 	clib_spinlock_init (&um->peekers_readers_locks[i]);
 	clib_spinlock_init (&um->peekers_write_locks[i]);
       }

   um->local_to_input_edge[UDP_IP4] =
     vlib_node_add_next (vm, udp4_local_node.index, udp4_input_node.index);
   um->local_to_input_edge[UDP_IP6] =
     vlib_node_add_next (vm, udp6_local_node.index, udp6_input_node.index);

   um->default_mtu = 1500;
   return 0;
 }

 /* *INDENT-OFF* */
 VLIB_INIT_FUNCTION (udp_init) =
 {
   .runs_after = VLIB_INITS("ip_main_init", "ip4_lookup_init",
                            "ip6_lookup_init"),
 };
 /* *INDENT-ON* */

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* Copyright (c) 2016-2020 Cisco and/or its affiliates.
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at:
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <vnet/udp/udp.h>
	#include <vnet/session/session.h>
	#include <vnet/dpo/load_balance.h>
	#include <vnet/ip/ip4_inlines.h>
	#include <vnet/ip/ip6_inlines.h>
	#include <vppinfra/sparse_vec.h>

	udp_main_t udp_main;

	static void
	udp_connection_register_port (vlib_main_t * vm, u16 lcl_port, u8 is_ip4)
	{
	udp_main_t *um = &udp_main;
	udp_dst_port_info_t *pi;
	u16 *n;

	pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
	if (!pi)
	{
	udp_add_dst_port (um, lcl_port, 0, is_ip4);
	pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
	pi->n_connections = 1;
	}
	else
	{
	pi->n_connections += 1;
	/* Do not return. The fact that the pi is valid does not mean
	* it's up to date */
	}

	pi->node_index = is_ip4 ? udp4_input_node.index : udp6_input_node.index;
	pi->next_index = um->local_to_input_edge[is_ip4];

	/* Setup udp protocol -> next index sparse vector mapping. */
	if (is_ip4)
	n = sparse_vec_validate (um->next_by_dst_port4,
	clib_host_to_net_u16 (lcl_port));
	else
	n = sparse_vec_validate (um->next_by_dst_port6,
	clib_host_to_net_u16 (lcl_port));

	n[0] = pi->next_index;
	}

	static void
	udp_connection_unregister_port (u16 lcl_port, u8 is_ip4)
	{
	udp_main_t *um = &udp_main;
	udp_dst_port_info_t *pi;

	pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
	if (!pi)
	return;

	if (!pi->n_connections)
	{
	clib_warning ("no connections using port %u", lcl_port);
	return;
	}

	if (!clib_atomic_sub_fetch (&pi->n_connections, 1))
	udp_unregister_dst_port (0, lcl_port, is_ip4);
	}

	void
	udp_connection_share_port (u16 lcl_port, u8 is_ip4)
	{
	udp_main_t *um = &udp_main;
	udp_dst_port_info_t *pi;

	/* Done without a lock but the operation is atomic. Writers to pi hash
	* table and vector should be guarded by a barrier sync */
	pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
	clib_atomic_fetch_add_rel (&pi->n_connections, 1);
	}

	udp_connection_t *
	udp_connection_alloc (u32 thread_index)
	{
	udp_main_t *um = &udp_main;
	udp_connection_t *uc;
	u32 will_expand = 0;
	pool_get_aligned_will_expand (um->connections[thread_index], will_expand,
	CLIB_CACHE_LINE_BYTES);

	if (PREDICT_FALSE (will_expand))
	{
	clib_spinlock_lock_if_init (&udp_main.peekers_write_locks
	[thread_index]);
	pool_get_aligned (udp_main.connections[thread_index], uc,
	CLIB_CACHE_LINE_BYTES);
	clib_spinlock_unlock_if_init (&udp_main.peekers_write_locks
	[thread_index]);
	}
	else
	{
	pool_get_aligned (um->connections[thread_index], uc,
	CLIB_CACHE_LINE_BYTES);
	}
	clib_memset (uc, 0, sizeof (*uc));
	uc->c_c_index = uc - um->connections[thread_index];
	uc->c_thread_index = thread_index;
	uc->c_proto = TRANSPORT_PROTO_UDP;
	return uc;
	}

	void
	udp_connection_free (udp_connection_t * uc)
	{
	u32 thread_index = uc->c_thread_index;
	clib_spinlock_free (&uc->rx_lock);
	if (CLIB_DEBUG)
	clib_memset (uc, 0xFA, sizeof (*uc));
	pool_put (udp_main.connections[thread_index], uc);
	}

	static void
	udp_connection_cleanup (udp_connection_t * uc)
	{
	transport_endpoint_cleanup (TRANSPORT_PROTO_UDP, &uc->c_lcl_ip,
	uc->c_lcl_port);
	udp_connection_unregister_port (clib_net_to_host_u16 (uc->c_lcl_port),
	uc->c_is_ip4);
	udp_connection_free (uc);
	}

	void
	udp_connection_delete (udp_connection_t * uc)
	{
	session_transport_delete_notify (&uc->connection);
	udp_connection_cleanup (uc);
	}

	static u8
	udp_connection_port_used_extern (u16 lcl_port, u8 is_ip4)
	{
	udp_main_t *um = vnet_get_udp_main ();
	udp_dst_port_info_t *pi;

	pi = udp_get_dst_port_info (um, lcl_port, is_ip4);
	return (pi && !pi->n_connections
	&& udp_is_valid_dst_port (lcl_port, is_ip4));
	}

	static u16
	udp_default_mtu (udp_main_t * um, u8 is_ip4)
	{
	u16 ip_hlen = is_ip4 ? sizeof (ip4_header_t) : sizeof (ip6_header_t);
	return (um->default_mtu - sizeof (udp_header_t) - ip_hlen);
	}

	static u32
	udp_session_bind (u32 session_index, transport_endpoint_t * lcl)
	{
	udp_main_t *um = vnet_get_udp_main ();
	vlib_main_t *vm = vlib_get_main ();
	transport_endpoint_cfg_t *lcl_ext;
	udp_connection_t *listener;
	u16 lcl_port_ho;
	void *iface_ip;

	lcl_port_ho = clib_net_to_host_u16 (lcl->port);

	if (udp_connection_port_used_extern (lcl_port_ho, lcl->is_ip4))
	{
	clib_warning ("port already used");
	return SESSION_E_PORTINUSE;
	}

	pool_get (um->listener_pool, listener);
	clib_memset (listener, 0, sizeof (udp_connection_t));

	listener->c_lcl_port = lcl->port;
	listener->c_c_index = listener - um->listener_pool;

	/* If we are provided a sw_if_index, bind using one of its ips */
	if (ip_is_zero (&lcl->ip, 1) && lcl->sw_if_index != ENDPOINT_INVALID_INDEX)
	{
	if ((iface_ip = ip_interface_get_first_ip (lcl->sw_if_index,
	lcl->is_ip4)))
	ip_set (&lcl->ip, iface_ip, lcl->is_ip4);
	}
	ip_copy (&listener->c_lcl_ip, &lcl->ip, lcl->is_ip4);
	listener->c_is_ip4 = lcl->is_ip4;
	listener->c_proto = TRANSPORT_PROTO_UDP;
	listener->c_s_index = session_index;
	listener->c_fib_index = lcl->fib_index;
	listener->mss = udp_default_mtu (um, listener->c_is_ip4);
	listener->flags \|= UDP_CONN_F_OWNS_PORT \| UDP_CONN_F_LISTEN;
	lcl_ext = (transport_endpoint_cfg_t *) lcl;
	if (lcl_ext->transport_flags & TRANSPORT_CFG_F_CONNECTED)
	listener->flags \|= UDP_CONN_F_CONNECTED;
	else
	listener->c_flags \|= TRANSPORT_CONNECTION_F_CLESS;
	clib_spinlock_init (&listener->rx_lock);

	udp_connection_register_port (vm, lcl_port_ho, lcl->is_ip4);
	return listener->c_c_index;
	}

	static u32
	udp_session_unbind (u32 listener_index)
	{
	udp_main_t *um = &udp_main;
	udp_connection_t *listener;

	listener = udp_listener_get (listener_index);
	udp_connection_unregister_port (clib_net_to_host_u16 (listener->c_lcl_port),
	listener->c_is_ip4);
	clib_spinlock_free (&listener->rx_lock);
	pool_put (um->listener_pool, listener);
	return 0;
	}

	static transport_connection_t *
	udp_session_get_listener (u32 listener_index)
	{
	udp_connection_t *us;

	us = udp_listener_get (listener_index);
	return &us->connection;
	}

	static u32
	udp_push_header (transport_connection_t * tc, vlib_buffer_t * b)
	{
	udp_connection_t *uc;
	vlib_main_t *vm = vlib_get_main ();

	uc = udp_connection_from_transport (tc);

	vlib_buffer_push_udp (b, uc->c_lcl_port, uc->c_rmt_port, 1);
	if (tc->is_ip4)
	vlib_buffer_push_ip4_custom (vm, b, &uc->c_lcl_ip4, &uc->c_rmt_ip4,
	IP_PROTOCOL_UDP, 1 /* csum offload */,
	0 /* is_df */, uc->c_dscp);
	else
	vlib_buffer_push_ip6 (vm, b, &uc->c_lcl_ip6, &uc->c_rmt_ip6,
	IP_PROTOCOL_UDP);
	vnet_buffer (b)->sw_if_index[VLIB_RX] = 0;
	vnet_buffer (b)->sw_if_index[VLIB_TX] = uc->c_fib_index;
	b->flags \|= VNET_BUFFER_F_LOCALLY_ORIGINATED;

	if (PREDICT_FALSE (uc->flags & UDP_CONN_F_CLOSING))
	{
	if (!transport_max_tx_dequeue (&uc->connection))
	udp_connection_delete (uc);
	}

	return 0;
	}

	static transport_connection_t *
	udp_session_get (u32 connection_index, u32 thread_index)
	{
	udp_connection_t *uc;
	uc = udp_connection_get (connection_index, thread_index);
	if (uc)
	return &uc->connection;
	return 0;
	}

	static void
	udp_session_close (u32 connection_index, u32 thread_index)
	{
	udp_connection_t *uc;

	uc = udp_connection_get (connection_index, thread_index);
	if (!uc)
	return;

	if (!transport_max_tx_dequeue (&uc->connection))
	udp_connection_delete (uc);
	else
	uc->flags \|= UDP_CONN_F_CLOSING;
	}

	static void
	udp_session_cleanup (u32 connection_index, u32 thread_index)
	{
	udp_connection_t *uc;
	uc = udp_connection_get (connection_index, thread_index);
	if (!uc)
	return;
	if (uc->flags & UDP_CONN_F_MIGRATED)
	udp_connection_free (uc);
	else
	udp_connection_cleanup (uc);
	}

	static int
	udp_session_send_params (transport_connection_t * tconn,
	transport_send_params_t * sp)
	{
	udp_connection_t *uc;

	uc = udp_connection_from_transport (tconn);

	/* No constraint on TX window */
	sp->snd_space = ~0;
	/* TODO figure out MTU of output interface */
	sp->snd_mss = uc->mss;
	sp->tx_offset = 0;
	sp->flags = 0;
	return 0;
	}

	static int
	udp_open_connection (transport_endpoint_cfg_t * rmt)
	{
	vlib_main_t *vm = vlib_get_main ();
	u32 thread_index = vm->thread_index;
	udp_main_t *um = &udp_main;
	ip46_address_t lcl_addr;
	udp_connection_t *uc;
	u16 lcl_port;
	int rv;

	rv = transport_alloc_local_endpoint (TRANSPORT_PROTO_UDP, rmt, &lcl_addr,
	&lcl_port);
	if (rv)
	{
	if (rv != SESSION_E_PORTINUSE)
	return rv;

	if (udp_connection_port_used_extern (lcl_port, rmt->is_ip4))
	return SESSION_E_PORTINUSE;

	/* If port in use, check if 5-tuple is also in use */
	if (session_lookup_connection (rmt->fib_index, &lcl_addr, &rmt->ip,
	lcl_port, rmt->port, TRANSPORT_PROTO_UDP,
	rmt->is_ip4))
	return SESSION_E_PORTINUSE;

	/* 5-tuple is available so increase lcl endpoint refcount and proceed
	* with connection allocation */
	transport_share_local_endpoint (TRANSPORT_PROTO_UDP, &lcl_addr,
	lcl_port);
	goto conn_alloc;
	}

	if (udp_is_valid_dst_port (lcl_port, rmt->is_ip4))
	{
	/* If specific source port was requested abort */
	if (rmt->peer.port)
	return SESSION_E_PORTINUSE;

	/* Try to find a port that's not used */
	while (udp_is_valid_dst_port (lcl_port, rmt->is_ip4))
	{
	lcl_port = transport_alloc_local_port (TRANSPORT_PROTO_UDP,
	&lcl_addr);
	if (lcl_port < 1)
	return SESSION_E_PORTINUSE;
	}
	}

	conn_alloc:

	udp_connection_register_port (vm, lcl_port, rmt->is_ip4);

	/* We don't poll main thread if we have workers */
	thread_index = transport_cl_thread ();

	uc = udp_connection_alloc (thread_index);
	ip_copy (&uc->c_rmt_ip, &rmt->ip, rmt->is_ip4);
	ip_copy (&uc->c_lcl_ip, &lcl_addr, rmt->is_ip4);
	uc->c_rmt_port = rmt->port;
	uc->c_lcl_port = clib_host_to_net_u16 (lcl_port);
	uc->c_is_ip4 = rmt->is_ip4;
	uc->c_proto = TRANSPORT_PROTO_UDP;
	uc->c_fib_index = rmt->fib_index;
	uc->c_dscp = rmt->dscp;
	uc->mss = rmt->mss ? rmt->mss : udp_default_mtu (um, uc->c_is_ip4);
	uc->flags \|= UDP_CONN_F_OWNS_PORT;
	if (rmt->transport_flags & TRANSPORT_CFG_F_CONNECTED)
	{
	uc->flags \|= UDP_CONN_F_CONNECTED;
	}
	else
	{
	clib_spinlock_init (&uc->rx_lock);
	uc->c_flags \|= TRANSPORT_CONNECTION_F_CLESS;
	}

	return uc->c_c_index;
	}

	static transport_connection_t *
	udp_session_get_half_open (u32 conn_index)
	{
	udp_connection_t *uc;
	u32 thread_index;

	/* We don't poll main thread if we have workers */
	thread_index = transport_cl_thread ();
	uc = udp_connection_get (conn_index, thread_index);
	if (!uc)
	return 0;
	return &uc->connection;
	}

	static u8 *
	format_udp_session (u8 * s, va_list * args)
	{
	u32 uci = va_arg (*args, u32);
	u32 thread_index = va_arg (*args, u32);
	u32 verbose = va_arg (*args, u32);
	udp_connection_t *uc;

	uc = udp_connection_get (uci, thread_index);
	return format (s, "%U", format_udp_connection, uc, verbose);
	}

	static u8 *
	format_udp_half_open_session (u8 * s, va_list * args)
	{
	u32 __clib_unused tci = va_arg (*args, u32);
	u32 __clib_unused thread_index = va_arg (*args, u32);
	clib_warning ("BUG");
	return 0;
	}

	static u8 *
	format_udp_listener_session (u8 * s, va_list * args)
	{
	u32 tci = va_arg (*args, u32);
	u32 __clib_unused thread_index = va_arg (*args, u32);
	u32 verbose = va_arg (*args, u32);
	udp_connection_t *uc = udp_listener_get (tci);
	return format (s, "%U", format_udp_connection, uc, verbose);
	}

	/* INDENT-OFF */
	static const transport_proto_vft_t udp_proto = {
	.start_listen = udp_session_bind,
	.connect = udp_open_connection,
	.stop_listen = udp_session_unbind,
	.push_header = udp_push_header,
	.get_connection = udp_session_get,
	.get_listener = udp_session_get_listener,
	.get_half_open = udp_session_get_half_open,
	.close = udp_session_close,
	.cleanup = udp_session_cleanup,
	.send_params = udp_session_send_params,
	.format_connection = format_udp_session,
	.format_half_open = format_udp_half_open_session,
	.format_listener = format_udp_listener_session,
	.transport_options = {
	.name = "udp",
	.short_name = "U",
	.tx_type = TRANSPORT_TX_DGRAM,
	.service_type = TRANSPORT_SERVICE_CL,
	},
	};
	/* INDENT-ON */

	static clib_error_t *
	udp_init (vlib_main_t * vm)
	{
	udp_main_t *um = vnet_get_udp_main ();
	ip_main_t *im = &ip_main;
	vlib_thread_main_t *tm = vlib_get_thread_main ();
	u32 num_threads;
	ip_protocol_info_t *pi;
	int i;

	/*
	* Registrations
	*/

	/* IP registration */
	pi = ip_get_protocol_info (im, IP_PROTOCOL_UDP);
	if (pi == 0)
	return clib_error_return (0, "UDP protocol info AWOL");
	pi->format_header = format_udp_header;
	pi->unformat_pg_edit = unformat_pg_udp_header;

	/* Register as transport with URI */
	transport_register_protocol (TRANSPORT_PROTO_UDP, &udp_proto,
	FIB_PROTOCOL_IP4, ip4_lookup_node.index);
	transport_register_protocol (TRANSPORT_PROTO_UDP, &udp_proto,
	FIB_PROTOCOL_IP6, ip6_lookup_node.index);

	/*
	* Initialize data structures
	*/

	num_threads = 1 /* main thread */ + tm->n_threads;
	vec_validate (um->connections, num_threads - 1);
	vec_validate (um->connection_peekers, num_threads - 1);
	vec_validate (um->peekers_readers_locks, num_threads - 1);
	vec_validate (um->peekers_write_locks, num_threads - 1);

	if (num_threads > 1)
	for (i = 0; i < num_threads; i++)
	{
	clib_spinlock_init (&um->peekers_readers_locks[i]);
	clib_spinlock_init (&um->peekers_write_locks[i]);
	}

	um->local_to_input_edge[UDP_IP4] =
	vlib_node_add_next (vm, udp4_local_node.index, udp4_input_node.index);
	um->local_to_input_edge[UDP_IP6] =
	vlib_node_add_next (vm, udp6_local_node.index, udp6_input_node.index);

	um->default_mtu = 1500;
	return 0;
	}

	/* INDENT-OFF */
	VLIB_INIT_FUNCTION (udp_init) =
	{
	.runs_after = VLIB_INITS("ip_main_init", "ip4_lookup_init",
	"ip6_lookup_init"),
	};
	/* INDENT-ON */

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/