tipc: add ip/udp media type

The ip/udp bearer can be configured in a point-to-point
mode by specifying both local and remote ip/hostname,
or it can be enabled in multicast mode, where links are
established to all tipc nodes that have joined the same
multicast group. The multicast IP address is generated
based on the TIPC network ID, but can be overridden by
using another multicast address as remote ip.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 470 insertions, 8 deletions

diff --git a/net/tipc/Kconfig b/net/tipc/Kconfig
index 91c8a8e031db..c25a3a149dc4 100644
--- a/net/tipc/Kconfig
+++ b/net/tipc/Kconfig
@@ -26,3 +26,11 @@ config TIPC_MEDIA_IB
 	help
 	  Saying Y here will enable support for running TIPC on
 	  IP-over-InfiniBand devices.
+config TIPC_MEDIA_UDP
+	bool "IP/UDP media type support"
+	depends on TIPC
+	select NET_UDP_TUNNEL
+	help
+	  Saying Y here will enable support for running TIPC over IP/UDP
+	bool
+	default y
diff --git a/net/tipc/Makefile b/net/tipc/Makefile
index 599b1a540d2b..57e460be4692 100644
--- a/net/tipc/Makefile
+++ b/net/tipc/Makefile
@@ -10,5 +10,6 @@ tipc-y	+= addr.o bcast.o bearer.o \
 	   netlink.o netlink_compat.o node.o socket.o eth_media.o \
 	   server.o socket.o
 
+tipc-$(CONFIG_TIPC_MEDIA_UDP)	+= udp_media.o
 tipc-$(CONFIG_TIPC_MEDIA_IB)	+= ib_media.o
 tipc-$(CONFIG_SYSCTL)		+= sysctl.o
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index af6deeb397a8..840db89e4283 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -48,6 +48,9 @@ static struct tipc_media * const media_info_array[] = {
 #ifdef CONFIG_TIPC_MEDIA_IB
 	&ib_media_info,
 #endif
+#ifdef CONFIG_TIPC_MEDIA_UDP
+	&udp_media_info,
+#endif
 	NULL
 };
 
@@ -216,7 +219,8 @@ void tipc_bearer_remove_dest(struct net *net, u32 bearer_id, u32 dest)
  * tipc_enable_bearer - enable bearer with the given name
  */
 static int tipc_enable_bearer(struct net *net, const char *name,
-			      u32 disc_domain, u32 priority)
+			      u32 disc_domain, u32 priority,
+			      struct nlattr *attr[])
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);
 	struct tipc_bearer *b_ptr;
@@ -304,7 +308,7 @@ restart:
 
 	strcpy(b_ptr->name, name);
 	b_ptr->media = m_ptr;
-	res = m_ptr->enable_media(net, b_ptr);
+	res = m_ptr->enable_media(net, b_ptr, attr);
 	if (res) {
 		pr_warn("Bearer <%s> rejected, enable failure (%d)\n",
 			name, -res);
@@ -372,7 +376,8 @@ static void bearer_disable(struct net *net, struct tipc_bearer *b_ptr,
 	kfree_rcu(b_ptr, rcu);
 }
 
-int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b)
+int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
+			 struct nlattr *attr[])
 {
 	struct net_device *dev;
 	char *driver_name = strchr((const char *)b->name, ':') + 1;
@@ -791,7 +796,7 @@ int tipc_nl_bearer_enable(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	rtnl_lock();
-	err = tipc_enable_bearer(net, bearer, domain, prio);
+	err = tipc_enable_bearer(net, bearer, domain, prio, attrs);
 	if (err) {
 		rtnl_unlock();
 		return err;
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 097aff08ad5b..5cad243ee8fc 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -41,7 +41,7 @@
 #include <net/genetlink.h>
 
 #define MAX_BEARERS	2
-#define MAX_MEDIA	2
+#define MAX_MEDIA	3
 #define MAX_NODES	4096
 #define WSIZE		32
 
@@ -59,6 +59,7 @@
  */
 #define TIPC_MEDIA_TYPE_ETH	1
 #define TIPC_MEDIA_TYPE_IB	2
+#define TIPC_MEDIA_TYPE_UDP	3
 
 /**
  * struct tipc_node_map - set of node identifiers
@@ -104,7 +105,8 @@ struct tipc_media {
 	int (*send_msg)(struct net *net, struct sk_buff *buf,
 			struct tipc_bearer *b_ptr,
 			struct tipc_media_addr *dest);
-	int (*enable_media)(struct net *net, struct tipc_bearer *b_ptr);
+	int (*enable_media)(struct net *net, struct tipc_bearer *b_ptr,
+			    struct nlattr *attr[]);
 	void (*disable_media)(struct tipc_bearer *b_ptr);
 	int (*addr2str)(struct tipc_media_addr *addr,
 			char *strbuf,
@@ -183,6 +185,9 @@ extern struct tipc_media eth_media_info;
 #ifdef CONFIG_TIPC_MEDIA_IB
 extern struct tipc_media ib_media_info;
 #endif
+#ifdef CONFIG_TIPC_MEDIA_UDP
+extern struct tipc_media udp_media_info;
+#endif
 
 int tipc_nl_bearer_disable(struct sk_buff *skb, struct genl_info *info);
 int tipc_nl_bearer_enable(struct sk_buff *skb, struct genl_info *info);
@@ -197,7 +202,8 @@ int tipc_nl_media_set(struct sk_buff *skb, struct genl_info *info);
 int tipc_media_set_priority(const char *name, u32 new_value);
 int tipc_media_set_window(const char *name, u32 new_value);
 void tipc_media_addr_printf(char *buf, int len, struct tipc_media_addr *a);
-int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b);
+int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
+			 struct nlattr *attrs[]);
 void tipc_disable_l2_media(struct tipc_bearer *b);
 int tipc_l2_send_msg(struct net *net, struct sk_buff *buf,
 		     struct tipc_bearer *b, struct tipc_media_addr *dest);
diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index c1cc8d7a5d52..fa167846d1ab 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -87,7 +87,7 @@ struct plist;
  * Note: Headroom should be a multiple of 4 to ensure the TIPC header fields
  *       are word aligned for quicker access
  */
-#define BUF_HEADROOM LL_MAX_HEADER
+#define BUF_HEADROOM (LL_MAX_HEADER + 48)
 
 struct tipc_skb_cb {
 	void *handle;
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
new file mode 100644
index 000000000000..0d10001db40d
--- /dev/null
+++ b/net/tipc/udp_media.c
@@ -0,0 +1,442 @@
+/* net/tipc/udp_media.c: IP bearer support for TIPC
+ *
+ * Copyright (c) 2015, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/socket.h>
+#include <linux/ip.h>
+#include <linux/udp.h>
+#include <linux/inet.h>
+#include <linux/inetdevice.h>
+#include <linux/igmp.h>
+#include <linux/kernel.h>
+#include <linux/workqueue.h>
+#include <linux/list.h>
+#include <net/sock.h>
+#include <net/ip.h>
+#include <net/udp_tunnel.h>
+#include <linux/tipc_netlink.h>
+#include "core.h"
+#include "bearer.h"
+
+/* IANA assigned UDP port */
+#define UDP_PORT_DEFAULT	6118
+
+static const struct nla_policy tipc_nl_udp_policy[TIPC_NLA_UDP_MAX + 1] = {
+	[TIPC_NLA_UDP_UNSPEC]	= {.type = NLA_UNSPEC},
+	[TIPC_NLA_UDP_LOCAL]	= {.type = NLA_BINARY,
+				   .len = sizeof(struct sockaddr_storage)},
+	[TIPC_NLA_UDP_REMOTE]	= {.type = NLA_BINARY,
+				   .len = sizeof(struct sockaddr_storage)},
+};
+
+/**
+ * struct udp_media_addr - IP/UDP addressing information
+ *
+ * This is the bearer level originating address used in neighbor discovery
+ * messages, and all fields should be in network byte order
+ */
+struct udp_media_addr {
+	__be16	proto;
+	__be16	udp_port;
+	union {
+		struct in_addr ipv4;
+		struct in6_addr ipv6;
+	};
+};
+
+/**
+ * struct udp_bearer - ip/udp bearer data structure
+ * @bearer:	associated generic tipc bearer
+ * @ubsock:	bearer associated socket
+ * @ifindex:	local address scope
+ * @work:	used to schedule deferred work on a bearer
+ */
+struct udp_bearer {
+	struct tipc_bearer __rcu *bearer;
+	struct socket *ubsock;
+	u32 ifindex;
+	struct work_struct work;
+};
+
+/* udp_media_addr_set - convert a ip/udp address to a TIPC media address */
+static void tipc_udp_media_addr_set(struct tipc_media_addr *addr,
+				    struct udp_media_addr *ua)
+{
+	memset(addr, 0, sizeof(struct tipc_media_addr));
+	addr->media_id = TIPC_MEDIA_TYPE_UDP;
+	memcpy(addr->value, ua, sizeof(struct udp_media_addr));
+	if (ntohs(ua->proto) == ETH_P_IP) {
+		if (ipv4_is_multicast(ua->ipv4.s_addr))
+			addr->broadcast = 1;
+	} else if (ntohs(ua->proto) == ETH_P_IPV6) {
+		if (ipv6_addr_type(&ua->ipv6) & IPV6_ADDR_MULTICAST)
+			addr->broadcast = 1;
+	} else {
+		pr_err("Invalid UDP media address\n");
+	}
+}
+
+/* tipc_udp_addr2str - convert ip/udp address to string */
+static int tipc_udp_addr2str(struct tipc_media_addr *a, char *buf, int size)
+{
+	struct udp_media_addr *ua = (struct udp_media_addr *)&a->value;
+
+	if (ntohs(ua->proto) == ETH_P_IP)
+		snprintf(buf, size, "%pI4:%u", &ua->ipv4, ntohs(ua->udp_port));
+	else if (ntohs(ua->proto) == ETH_P_IPV6)
+		snprintf(buf, size, "%pI6:%u", &ua->ipv6, ntohs(ua->udp_port));
+	else
+		pr_err("Invalid UDP media address\n");
+	return 0;
+}
+
+/* tipc_udp_msg2addr - extract an ip/udp address from a TIPC ndisc message */
+static int tipc_udp_msg2addr(struct tipc_bearer *b, struct tipc_media_addr *a,
+			     char *msg)
+{
+	struct udp_media_addr *ua;
+
+	ua = (struct udp_media_addr *) (msg + TIPC_MEDIA_ADDR_OFFSET);
+	if (msg[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_UDP)
+		return -EINVAL;
+	tipc_udp_media_addr_set(a, ua);
+	return 0;
+}
+
+/* tipc_udp_addr2msg - write an ip/udp address to a TIPC ndisc message */
+static int tipc_udp_addr2msg(char *msg, struct tipc_media_addr *a)
+{
+	memset(msg, 0, TIPC_MEDIA_INFO_SIZE);
+	msg[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_UDP;
+	memcpy(msg + TIPC_MEDIA_ADDR_OFFSET, a->value,
+	       sizeof(struct udp_media_addr));
+	return 0;
+}
+
+/* tipc_send_msg - enqueue a send request */
+static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
+			     struct tipc_bearer *b,
+			     struct tipc_media_addr *dest)
+{
+	int ttl, err = 0;
+	struct udp_bearer *ub;
+	struct udp_media_addr *dst = (struct udp_media_addr *)&dest->value;
+	struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
+	struct sk_buff *clone;
+	struct rtable *rt;
+
+	clone = skb_clone(skb, GFP_ATOMIC);
+	skb_set_inner_protocol(clone, htons(ETH_P_TIPC));
+	ub = rcu_dereference_rtnl(b->media_ptr);
+	if (!ub) {
+		err = -ENODEV;
+		goto tx_error;
+	}
+	if (htons(dst->proto) == ETH_P_IP) {
+		struct flowi4 fl = {
+			.daddr = dst->ipv4.s_addr,
+			.saddr = src->ipv4.s_addr,
+			.flowi4_mark = clone->mark,
+			.flowi4_proto = IPPROTO_UDP
+		};
+		rt = ip_route_output_key(net, &fl);
+		if (IS_ERR(rt)) {
+			err = PTR_ERR(rt);
+			goto tx_error;
+		}
+		ttl = ip4_dst_hoplimit(&rt->dst);
+		err = udp_tunnel_xmit_skb(rt, clone, src->ipv4.s_addr,
+					  dst->ipv4.s_addr, 0, ttl, 0,
+					  src->udp_port, dst->udp_port,
+					  false, true);
+		if (err < 0) {
+			ip_rt_put(rt);
+			goto tx_error;
+		}
+#if IS_ENABLED(CONFIG_IPV6)
+	} else {
+		struct dst_entry *ndst;
+		struct flowi6 fl6 = {
+			.flowi6_oif = ub->ifindex,
+			.daddr = dst->ipv6,
+			.saddr = src->ipv6,
+			.flowi6_proto = IPPROTO_UDP
+		};
+		err = ip6_dst_lookup(ub->ubsock->sk, &ndst, &fl6);
+		if (err)
+			goto tx_error;
+		ttl = ip6_dst_hoplimit(ndst);
+		err = udp_tunnel6_xmit_skb(ndst, clone, ndst->dev, &src->ipv6,
+					   &dst->ipv6, 0, ttl, src->udp_port,
+					   dst->udp_port, false);
+#endif
+	}
+	return err;
+
+tx_error:
+	kfree_skb(clone);
+	return err;
+}
+
+/* tipc_udp_recv - read data from bearer socket */
+static int tipc_udp_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct udp_bearer *ub;
+	struct tipc_bearer *b;
+
+	ub = rcu_dereference_sk_user_data(sk);
+	if (!ub) {
+		pr_err_ratelimited("Failed to get UDP bearer reference");
+		kfree_skb(skb);
+		return 0;
+	}
+
+	skb_pull(skb, sizeof(struct udphdr));
+	rcu_read_lock();
+	b = rcu_dereference_rtnl(ub->bearer);
+
+	if (b) {
+		tipc_rcv(sock_net(sk), skb, b);
+		rcu_read_unlock();
+		return 0;
+	}
+	rcu_read_unlock();
+	kfree_skb(skb);
+	return 0;
+}
+
+static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
+{
+	int err = 0;
+	struct ip_mreqn mreqn;
+	struct sock *sk = ub->ubsock->sk;
+
+	if (ntohs(remote->proto) == ETH_P_IP) {
+		if (!ipv4_is_multicast(remote->ipv4.s_addr))
+			return 0;
+		mreqn.imr_multiaddr = remote->ipv4;
+		mreqn.imr_ifindex = ub->ifindex;
+		err = __ip_mc_join_group(sk, &mreqn);
+	} else {
+		if (!ipv6_addr_is_multicast(&remote->ipv6))
+			return 0;
+		err = __ipv6_sock_mc_join(sk, ub->ifindex, &remote->ipv6);
+	}
+	return err;
+}
+
+/**
+ * parse_options - build local/remote addresses from configuration
+ * @attrs:	netlink config data
+ * @ub:		UDP bearer instance
+ * @local:	local bearer IP address/port
+ * @remote:	peer or multicast IP/port
+ */
+static int parse_options(struct nlattr *attrs[], struct udp_bearer *ub,
+			 struct udp_media_addr *local,
+			 struct udp_media_addr *remote)
+{
+	struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
+	struct sockaddr_storage *sa_local, *sa_remote;
+
+	if (!attrs[TIPC_NLA_BEARER_UDP_OPTS])
+		goto err;
+	if (nla_parse_nested(opts, TIPC_NLA_UDP_MAX,
+			     attrs[TIPC_NLA_BEARER_UDP_OPTS],
+			     tipc_nl_udp_policy))
+		goto err;
+	if (opts[TIPC_NLA_UDP_LOCAL] && opts[TIPC_NLA_UDP_REMOTE]) {
+		sa_local = nla_data(opts[TIPC_NLA_UDP_LOCAL]);
+		sa_remote = nla_data(opts[TIPC_NLA_UDP_REMOTE]);
+	} else {
+err:
+		pr_err("Invalid UDP bearer configuration");
+		return -EINVAL;
+	}
+	if ((sa_local->ss_family & sa_remote->ss_family) == AF_INET) {
+		struct sockaddr_in *ip4;
+
+		ip4 = (struct sockaddr_in *)sa_local;
+		local->proto = htons(ETH_P_IP);
+		local->udp_port = ip4->sin_port;
+		local->ipv4.s_addr = ip4->sin_addr.s_addr;
+
+		ip4 = (struct sockaddr_in *)sa_remote;
+		remote->proto = htons(ETH_P_IP);
+		remote->udp_port = ip4->sin_port;
+		remote->ipv4.s_addr = ip4->sin_addr.s_addr;
+		return 0;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if ((sa_local->ss_family & sa_remote->ss_family) == AF_INET6) {
+		struct sockaddr_in6 *ip6;
+
+		ip6 = (struct sockaddr_in6 *)sa_local;
+		local->proto = htons(ETH_P_IPV6);
+		local->udp_port = ip6->sin6_port;
+		local->ipv6 = ip6->sin6_addr;
+		ub->ifindex = ip6->sin6_scope_id;
+
+		ip6 = (struct sockaddr_in6 *)sa_remote;
+		remote->proto = htons(ETH_P_IPV6);
+		remote->udp_port = ip6->sin6_port;
+		remote->ipv6 = ip6->sin6_addr;
+		return 0;
+#endif
+	}
+	return -EADDRNOTAVAIL;
+}
+
+/**
+ * tipc_udp_enable - callback to create a new udp bearer instance
+ * @net:	network namespace
+ * @b:		pointer to generic tipc_bearer
+ * @attrs:	netlink bearer configuration
+ *
+ * validate the bearer parameters and initialize the udp bearer
+ * rtnl_lock should be held
+ */
+static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
+			   struct nlattr *attrs[])
+{
+	int err = -EINVAL;
+	struct udp_bearer *ub;
+	struct udp_media_addr *remote;
+	struct udp_media_addr local = {0};
+	struct udp_port_cfg udp_conf = {0};
+	struct udp_tunnel_sock_cfg tuncfg = {0};
+
+	ub = kzalloc(sizeof(*ub), GFP_ATOMIC);
+	if (!ub)
+		return -ENOMEM;
+
+	remote = (struct udp_media_addr *)&b->bcast_addr.value;
+	memset(remote, 0, sizeof(struct udp_media_addr));
+	err = parse_options(attrs, ub, &local, remote);
+	if (err)
+		goto err;
+
+	b->bcast_addr.media_id = TIPC_MEDIA_TYPE_UDP;
+	b->bcast_addr.broadcast = 1;
+	rcu_assign_pointer(b->media_ptr, ub);
+	rcu_assign_pointer(ub->bearer, b);
+	tipc_udp_media_addr_set(&b->addr, &local);
+	if (htons(local.proto) == ETH_P_IP) {
+		struct net_device *dev;
+
+		dev = __ip_dev_find(net, local.ipv4.s_addr, false);
+		if (!dev) {
+			err = -ENODEV;
+			goto err;
+		}
+		udp_conf.family = AF_INET;
+		udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
+		udp_conf.use_udp_checksums = false;
+		ub->ifindex = dev->ifindex;
+		b->mtu = dev->mtu - sizeof(struct iphdr)
+			- sizeof(struct udphdr);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (htons(local.proto) == ETH_P_IPV6) {
+		udp_conf.family = AF_INET6;
+		udp_conf.use_udp6_tx_checksums = true;
+		udp_conf.use_udp6_rx_checksums = true;
+		udp_conf.local_ip6 = in6addr_any;
+		b->mtu = 1280;
+#endif
+	} else {
+		err = -EAFNOSUPPORT;
+		goto err;
+	}
+	udp_conf.local_udp_port = local.udp_port;
+	err = udp_sock_create(net, &udp_conf, &ub->ubsock);
+	if (err)
+		goto err;
+	tuncfg.sk_user_data = ub;
+	tuncfg.encap_type = 1;
+	tuncfg.encap_rcv = tipc_udp_recv;
+	tuncfg.encap_destroy = NULL;
+	setup_udp_tunnel_sock(net, ub->ubsock, &tuncfg);
+
+	if (enable_mcast(ub, remote))
+		goto err;
+	return 0;
+err:
+	kfree(ub);
+	return err;
+}
+
+/* cleanup_bearer - break the socket/bearer association */
+static void cleanup_bearer(struct work_struct *work)
+{
+	struct udp_bearer *ub = container_of(work, struct udp_bearer, work);
+
+	if (ub->ubsock)
+		udp_tunnel_sock_release(ub->ubsock);
+	synchronize_net();
+	kfree(ub);
+}
+
+/* tipc_udp_disable - detach bearer from socket */
+static void tipc_udp_disable(struct tipc_bearer *b)
+{
+	struct udp_bearer *ub;
+
+	ub = rcu_dereference_rtnl(b->media_ptr);
+	if (!ub) {
+		pr_err("UDP bearer instance not found\n");
+		return;
+	}
+	if (ub->ubsock)
+		sock_set_flag(ub->ubsock->sk, SOCK_DEAD);
+	RCU_INIT_POINTER(b->media_ptr, NULL);
+	RCU_INIT_POINTER(ub->bearer, NULL);
+
+	/* sock_release need to be done outside of rtnl lock */
+	INIT_WORK(&ub->work, cleanup_bearer);
+	schedule_work(&ub->work);
+}
+
+struct tipc_media udp_media_info = {
+	.send_msg	= tipc_udp_send_msg,
+	.enable_media	= tipc_udp_enable,
+	.disable_media	= tipc_udp_disable,
+	.addr2str	= tipc_udp_addr2str,
+	.addr2msg	= tipc_udp_addr2msg,
+	.msg2addr	= tipc_udp_msg2addr,
+	.priority	= TIPC_DEF_LINK_PRI,
+	.tolerance	= TIPC_DEF_LINK_TOL,
+	.window		= TIPC_DEF_LINK_WIN,
+	.type_id	= TIPC_MEDIA_TYPE_UDP,
+	.hwaddr_len	= 0,
+	.name		= "udp"
+};