1 files changed, 851 insertions, 0 deletions

diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
new file mode 100644
index 000000000..3e47501f0
--- /dev/null
+++ b/net/tipc/udp_media.c
@@ -0,0 +1,851 @@
+/* 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 <net/ipv6_stubs.h>
+#include <linux/tipc_netlink.h>
+#include "core.h"
+#include "addr.h"
+#include "net.h"
+#include "bearer.h"
+#include "netlink.h"
+#include "msg.h"
+#include "udp_media.h"
+
+/* IANA assigned UDP port */
+#define UDP_PORT_DEFAULT	6118
+
+#define UDP_MIN_HEADROOM        48
+
+/**
+ * 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	port;
+	union {
+		struct in_addr ipv4;
+		struct in6_addr ipv6;
+	};
+};
+
+/* struct udp_replicast - container for UDP remote addresses */
+struct udp_replicast {
+	struct udp_media_addr addr;
+	struct dst_cache dst_cache;
+	struct rcu_head rcu;
+	struct list_head list;
+};
+
+/**
+ * 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;
+	struct udp_replicast rcast;
+};
+
+static int tipc_udp_is_mcast_addr(struct udp_media_addr *addr)
+{
+	if (ntohs(addr->proto) == ETH_P_IP)
+		return ipv4_is_multicast(addr->ipv4.s_addr);
+#if IS_ENABLED(CONFIG_IPV6)
+	else
+		return ipv6_addr_is_multicast(&addr->ipv6);
+#endif
+	return 0;
+}
+
+/* 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 (tipc_udp_is_mcast_addr(ua))
+		addr->broadcast = TIPC_BROADCAST_SUPPORT;
+}
+
+/* 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->port));
+	else if (ntohs(ua->proto) == ETH_P_IPV6)
+		snprintf(buf, size, "%pI6:%u", &ua->ipv6, ntohs(ua->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_xmit(struct net *net, struct sk_buff *skb,
+			 struct udp_bearer *ub, struct udp_media_addr *src,
+			 struct udp_media_addr *dst, struct dst_cache *cache)
+{
+	struct dst_entry *ndst;
+	int ttl, err = 0;
+
+	local_bh_disable();
+	ndst = dst_cache_get(cache);
+	if (dst->proto == htons(ETH_P_IP)) {
+		struct rtable *rt = (struct rtable *)ndst;
+
+		if (!rt) {
+			struct flowi4 fl = {
+				.daddr = dst->ipv4.s_addr,
+				.saddr = src->ipv4.s_addr,
+				.flowi4_mark = skb->mark,
+				.flowi4_proto = IPPROTO_UDP
+			};
+			rt = ip_route_output_key(net, &fl);
+			if (IS_ERR(rt)) {
+				err = PTR_ERR(rt);
+				goto tx_error;
+			}
+			dst_cache_set_ip4(cache, &rt->dst, fl.saddr);
+		}
+
+		ttl = ip4_dst_hoplimit(&rt->dst);
+		udp_tunnel_xmit_skb(rt, ub->ubsock->sk, skb, src->ipv4.s_addr,
+				    dst->ipv4.s_addr, 0, ttl, 0, src->port,
+				    dst->port, false, true);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else {
+		if (!ndst) {
+			struct flowi6 fl6 = {
+				.flowi6_oif = ub->ifindex,
+				.daddr = dst->ipv6,
+				.saddr = src->ipv6,
+				.flowi6_proto = IPPROTO_UDP
+			};
+			ndst = ipv6_stub->ipv6_dst_lookup_flow(net,
+							       ub->ubsock->sk,
+							       &fl6, NULL);
+			if (IS_ERR(ndst)) {
+				err = PTR_ERR(ndst);
+				goto tx_error;
+			}
+			dst_cache_set_ip6(cache, ndst, &fl6.saddr);
+		}
+		ttl = ip6_dst_hoplimit(ndst);
+		err = udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, skb, NULL,
+					   &src->ipv6, &dst->ipv6, 0, ttl, 0,
+					   src->port, dst->port, false);
+#endif
+	}
+	local_bh_enable();
+	return err;
+
+tx_error:
+	local_bh_enable();
+	kfree_skb(skb);
+	return err;
+}
+
+static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
+			     struct tipc_bearer *b,
+			     struct tipc_media_addr *addr)
+{
+	struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
+	struct udp_media_addr *dst = (struct udp_media_addr *)&addr->value;
+	struct udp_replicast *rcast;
+	struct udp_bearer *ub;
+	int err = 0;
+
+	if (skb_headroom(skb) < UDP_MIN_HEADROOM) {
+		err = pskb_expand_head(skb, UDP_MIN_HEADROOM, 0, GFP_ATOMIC);
+		if (err)
+			goto out;
+	}
+
+	skb_set_inner_protocol(skb, htons(ETH_P_TIPC));
+	ub = rcu_dereference(b->media_ptr);
+	if (!ub) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	if (addr->broadcast != TIPC_REPLICAST_SUPPORT)
+		return tipc_udp_xmit(net, skb, ub, src, dst,
+				     &ub->rcast.dst_cache);
+
+	/* Replicast, send an skb to each configured IP address */
+	list_for_each_entry_rcu(rcast, &ub->rcast.list, list) {
+		struct sk_buff *_skb;
+
+		_skb = pskb_copy(skb, GFP_ATOMIC);
+		if (!_skb) {
+			err = -ENOMEM;
+			goto out;
+		}
+
+		err = tipc_udp_xmit(net, _skb, ub, src, &rcast->addr,
+				    &rcast->dst_cache);
+		if (err)
+			goto out;
+	}
+	err = 0;
+out:
+	kfree_skb(skb);
+	return err;
+}
+
+static bool tipc_udp_is_known_peer(struct tipc_bearer *b,
+				   struct udp_media_addr *addr)
+{
+	struct udp_replicast *rcast, *tmp;
+	struct udp_bearer *ub;
+
+	ub = rcu_dereference_rtnl(b->media_ptr);
+	if (!ub) {
+		pr_err_ratelimited("UDP bearer instance not found\n");
+		return false;
+	}
+
+	list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
+		if (!memcmp(&rcast->addr, addr, sizeof(struct udp_media_addr)))
+			return true;
+	}
+
+	return false;
+}
+
+static int tipc_udp_rcast_add(struct tipc_bearer *b,
+			      struct udp_media_addr *addr)
+{
+	struct udp_replicast *rcast;
+	struct udp_bearer *ub;
+
+	ub = rcu_dereference_rtnl(b->media_ptr);
+	if (!ub)
+		return -ENODEV;
+
+	rcast = kmalloc(sizeof(*rcast), GFP_ATOMIC);
+	if (!rcast)
+		return -ENOMEM;
+
+	if (dst_cache_init(&rcast->dst_cache, GFP_ATOMIC)) {
+		kfree(rcast);
+		return -ENOMEM;
+	}
+
+	memcpy(&rcast->addr, addr, sizeof(struct udp_media_addr));
+
+	if (ntohs(addr->proto) == ETH_P_IP)
+		pr_info("New replicast peer: %pI4\n", &rcast->addr.ipv4);
+#if IS_ENABLED(CONFIG_IPV6)
+	else if (ntohs(addr->proto) == ETH_P_IPV6)
+		pr_info("New replicast peer: %pI6\n", &rcast->addr.ipv6);
+#endif
+	b->bcast_addr.broadcast = TIPC_REPLICAST_SUPPORT;
+	list_add_rcu(&rcast->list, &ub->rcast.list);
+	return 0;
+}
+
+static int tipc_udp_rcast_disc(struct tipc_bearer *b, struct sk_buff *skb)
+{
+	struct udp_media_addr src = {0};
+	struct udp_media_addr *dst;
+
+	dst = (struct udp_media_addr *)&b->bcast_addr.value;
+	if (tipc_udp_is_mcast_addr(dst))
+		return 0;
+
+	src.port = udp_hdr(skb)->source;
+
+	if (ip_hdr(skb)->version == 4) {
+		struct iphdr *iphdr = ip_hdr(skb);
+
+		src.proto = htons(ETH_P_IP);
+		src.ipv4.s_addr = iphdr->saddr;
+		if (ipv4_is_multicast(iphdr->daddr))
+			return 0;
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (ip_hdr(skb)->version == 6) {
+		struct ipv6hdr *iphdr = ipv6_hdr(skb);
+
+		src.proto = htons(ETH_P_IPV6);
+		src.ipv6 = iphdr->saddr;
+		if (ipv6_addr_is_multicast(&iphdr->daddr))
+			return 0;
+#endif
+	} else {
+		return 0;
+	}
+
+	if (likely(tipc_udp_is_known_peer(b, &src)))
+		return 0;
+
+	return tipc_udp_rcast_add(b, &src);
+}
+
+/* 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;
+	struct tipc_msg *hdr;
+	int err;
+
+	ub = rcu_dereference_sk_user_data(sk);
+	if (!ub) {
+		pr_err_ratelimited("Failed to get UDP bearer reference");
+		goto out;
+	}
+	skb_pull(skb, sizeof(struct udphdr));
+	hdr = buf_msg(skb);
+
+	b = rcu_dereference(ub->bearer);
+	if (!b)
+		goto out;
+
+	if (b && test_bit(0, &b->up)) {
+		TIPC_SKB_CB(skb)->flags = 0;
+		tipc_rcv(sock_net(sk), skb, b);
+		return 0;
+	}
+
+	if (unlikely(msg_user(hdr) == LINK_CONFIG)) {
+		err = tipc_udp_rcast_disc(b, skb);
+		if (err)
+			goto out;
+	}
+
+out:
+	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) {
+		mreqn.imr_multiaddr = remote->ipv4;
+		mreqn.imr_ifindex = ub->ifindex;
+		err = ip_mc_join_group(sk, &mreqn);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else {
+		err = ipv6_stub->ipv6_sock_mc_join(sk, ub->ifindex,
+						   &remote->ipv6);
+#endif
+	}
+	return err;
+}
+
+static int __tipc_nl_add_udp_addr(struct sk_buff *skb,
+				  struct udp_media_addr *addr, int nla_t)
+{
+	if (ntohs(addr->proto) == ETH_P_IP) {
+		struct sockaddr_in ip4;
+
+		memset(&ip4, 0, sizeof(ip4));
+		ip4.sin_family = AF_INET;
+		ip4.sin_port = addr->port;
+		ip4.sin_addr.s_addr = addr->ipv4.s_addr;
+		if (nla_put(skb, nla_t, sizeof(ip4), &ip4))
+			return -EMSGSIZE;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (ntohs(addr->proto) == ETH_P_IPV6) {
+		struct sockaddr_in6 ip6;
+
+		memset(&ip6, 0, sizeof(ip6));
+		ip6.sin6_family = AF_INET6;
+		ip6.sin6_port  = addr->port;
+		memcpy(&ip6.sin6_addr, &addr->ipv6, sizeof(struct in6_addr));
+		if (nla_put(skb, nla_t, sizeof(ip6), &ip6))
+			return -EMSGSIZE;
+#endif
+	}
+
+	return 0;
+}
+
+int tipc_udp_nl_dump_remoteip(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	u32 bid = cb->args[0];
+	u32 skip_cnt = cb->args[1];
+	u32 portid = NETLINK_CB(cb->skb).portid;
+	struct udp_replicast *rcast, *tmp;
+	struct tipc_bearer *b;
+	struct udp_bearer *ub;
+	void *hdr;
+	int err;
+	int i;
+
+	if (!bid && !skip_cnt) {
+		struct nlattr **attrs = genl_dumpit_info(cb)->attrs;
+		struct net *net = sock_net(skb->sk);
+		struct nlattr *battrs[TIPC_NLA_BEARER_MAX + 1];
+		char *bname;
+
+		if (!attrs[TIPC_NLA_BEARER])
+			return -EINVAL;
+
+		err = nla_parse_nested_deprecated(battrs, TIPC_NLA_BEARER_MAX,
+						  attrs[TIPC_NLA_BEARER],
+						  tipc_nl_bearer_policy, NULL);
+		if (err)
+			return err;
+
+		if (!battrs[TIPC_NLA_BEARER_NAME])
+			return -EINVAL;
+
+		bname = nla_data(battrs[TIPC_NLA_BEARER_NAME]);
+
+		rtnl_lock();
+		b = tipc_bearer_find(net, bname);
+		if (!b) {
+			rtnl_unlock();
+			return -EINVAL;
+		}
+		bid = b->identity;
+	} else {
+		struct net *net = sock_net(skb->sk);
+		struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+		rtnl_lock();
+		b = rtnl_dereference(tn->bearer_list[bid]);
+		if (!b) {
+			rtnl_unlock();
+			return -EINVAL;
+		}
+	}
+
+	ub = rtnl_dereference(b->media_ptr);
+	if (!ub) {
+		rtnl_unlock();
+		return -EINVAL;
+	}
+
+	i = 0;
+	list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
+		if (i < skip_cnt)
+			goto count;
+
+		hdr = genlmsg_put(skb, portid, cb->nlh->nlmsg_seq,
+				  &tipc_genl_family, NLM_F_MULTI,
+				  TIPC_NL_BEARER_GET);
+		if (!hdr)
+			goto done;
+
+		err = __tipc_nl_add_udp_addr(skb, &rcast->addr,
+					     TIPC_NLA_UDP_REMOTE);
+		if (err) {
+			genlmsg_cancel(skb, hdr);
+			goto done;
+		}
+		genlmsg_end(skb, hdr);
+count:
+		i++;
+	}
+done:
+	rtnl_unlock();
+	cb->args[0] = bid;
+	cb->args[1] = i;
+
+	return skb->len;
+}
+
+int tipc_udp_nl_add_bearer_data(struct tipc_nl_msg *msg, struct tipc_bearer *b)
+{
+	struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
+	struct udp_media_addr *dst;
+	struct udp_bearer *ub;
+	struct nlattr *nest;
+
+	ub = rtnl_dereference(b->media_ptr);
+	if (!ub)
+		return -ENODEV;
+
+	nest = nla_nest_start_noflag(msg->skb, TIPC_NLA_BEARER_UDP_OPTS);
+	if (!nest)
+		goto msg_full;
+
+	if (__tipc_nl_add_udp_addr(msg->skb, src, TIPC_NLA_UDP_LOCAL))
+		goto msg_full;
+
+	dst = (struct udp_media_addr *)&b->bcast_addr.value;
+	if (__tipc_nl_add_udp_addr(msg->skb, dst, TIPC_NLA_UDP_REMOTE))
+		goto msg_full;
+
+	if (!list_empty(&ub->rcast.list)) {
+		if (nla_put_flag(msg->skb, TIPC_NLA_UDP_MULTI_REMOTEIP))
+			goto msg_full;
+	}
+
+	nla_nest_end(msg->skb, nest);
+	return 0;
+msg_full:
+	nla_nest_cancel(msg->skb, nest);
+	return -EMSGSIZE;
+}
+
+/**
+ * tipc_parse_udp_addr - build udp media address from netlink data
+ * @nla:	netlink attribute containing sockaddr storage aligned address
+ * @addr:	tipc media address to fill with address, port and protocol type
+ * @scope_id:	IPv6 scope id pointer, not NULL indicates it's required
+ */
+
+static int tipc_parse_udp_addr(struct nlattr *nla, struct udp_media_addr *addr,
+			       u32 *scope_id)
+{
+	struct sockaddr_storage sa;
+
+	nla_memcpy(&sa, nla, sizeof(sa));
+	if (sa.ss_family == AF_INET) {
+		struct sockaddr_in *ip4 = (struct sockaddr_in *)&sa;
+
+		addr->proto = htons(ETH_P_IP);
+		addr->port = ip4->sin_port;
+		addr->ipv4.s_addr = ip4->sin_addr.s_addr;
+		return 0;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (sa.ss_family == AF_INET6) {
+		struct sockaddr_in6 *ip6 = (struct sockaddr_in6 *)&sa;
+
+		addr->proto = htons(ETH_P_IPV6);
+		addr->port = ip6->sin6_port;
+		memcpy(&addr->ipv6, &ip6->sin6_addr, sizeof(struct in6_addr));
+
+		/* Scope ID is only interesting for local addresses */
+		if (scope_id) {
+			int atype;
+
+			atype = ipv6_addr_type(&ip6->sin6_addr);
+			if (__ipv6_addr_needs_scope_id(atype) &&
+			    !ip6->sin6_scope_id) {
+				return -EINVAL;
+			}
+
+			*scope_id = ip6->sin6_scope_id ? : 0;
+		}
+
+		return 0;
+#endif
+	}
+	return -EADDRNOTAVAIL;
+}
+
+int tipc_udp_nl_bearer_add(struct tipc_bearer *b, struct nlattr *attr)
+{
+	int err;
+	struct udp_media_addr addr = {0};
+	struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
+	struct udp_media_addr *dst;
+
+	if (nla_parse_nested_deprecated(opts, TIPC_NLA_UDP_MAX, attr, tipc_nl_udp_policy, NULL))
+		return -EINVAL;
+
+	if (!opts[TIPC_NLA_UDP_REMOTE])
+		return -EINVAL;
+
+	err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_REMOTE], &addr, NULL);
+	if (err)
+		return err;
+
+	dst = (struct udp_media_addr *)&b->bcast_addr.value;
+	if (tipc_udp_is_mcast_addr(dst)) {
+		pr_err("Can't add remote ip to TIPC UDP multicast bearer\n");
+		return -EINVAL;
+	}
+
+	if (tipc_udp_is_known_peer(b, &addr))
+		return 0;
+
+	return tipc_udp_rcast_add(b, &addr);
+}
+
+/**
+ * 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 = {0};
+	struct udp_media_addr local = {0};
+	struct udp_port_cfg udp_conf = {0};
+	struct udp_tunnel_sock_cfg tuncfg = {NULL};
+	struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
+	u8 node_id[NODE_ID_LEN] = {0,};
+	struct net_device *dev;
+	int rmcast = 0;
+
+	ub = kzalloc(sizeof(*ub), GFP_ATOMIC);
+	if (!ub)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&ub->rcast.list);
+
+	if (!attrs[TIPC_NLA_BEARER_UDP_OPTS])
+		goto err;
+
+	if (nla_parse_nested_deprecated(opts, TIPC_NLA_UDP_MAX, attrs[TIPC_NLA_BEARER_UDP_OPTS], tipc_nl_udp_policy, NULL))
+		goto err;
+
+	if (!opts[TIPC_NLA_UDP_LOCAL] || !opts[TIPC_NLA_UDP_REMOTE]) {
+		pr_err("Invalid UDP bearer configuration");
+		err = -EINVAL;
+		goto err;
+	}
+
+	err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_LOCAL], &local,
+				  &ub->ifindex);
+	if (err)
+		goto err;
+
+	err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_REMOTE], &remote, NULL);
+	if (err)
+		goto err;
+
+	if (remote.proto != local.proto) {
+		err = -EINVAL;
+		goto err;
+	}
+
+	/* Checking remote ip address */
+	rmcast = tipc_udp_is_mcast_addr(&remote);
+
+	/* Autoconfigure own node identity if needed */
+	if (!tipc_own_id(net)) {
+		memcpy(node_id, local.ipv6.in6_u.u6_addr8, 16);
+		tipc_net_init(net, node_id, 0);
+	}
+	if (!tipc_own_id(net)) {
+		pr_warn("Failed to set node id, please configure manually\n");
+		err = -EINVAL;
+		goto err;
+	}
+
+	b->bcast_addr.media_id = TIPC_MEDIA_TYPE_UDP;
+	b->bcast_addr.broadcast = TIPC_BROADCAST_SUPPORT;
+	rcu_assign_pointer(b->media_ptr, ub);
+	rcu_assign_pointer(ub->bearer, b);
+	tipc_udp_media_addr_set(&b->addr, &local);
+	if (local.proto == htons(ETH_P_IP)) {
+		dev = __ip_dev_find(net, local.ipv4.s_addr, false);
+		if (!dev) {
+			err = -ENODEV;
+			goto err;
+		}
+		udp_conf.family = AF_INET;
+
+		/* Switch to use ANY to receive packets from group */
+		if (rmcast)
+			udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
+		else
+			udp_conf.local_ip.s_addr = local.ipv4.s_addr;
+		udp_conf.use_udp_checksums = false;
+		ub->ifindex = dev->ifindex;
+		b->encap_hlen = sizeof(struct iphdr) + sizeof(struct udphdr);
+		if (tipc_mtu_bad(dev, b->encap_hlen)) {
+			err = -EINVAL;
+			goto err;
+		}
+		b->mtu = b->media->mtu;
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (local.proto == htons(ETH_P_IPV6)) {
+		dev = ub->ifindex ? __dev_get_by_index(net, ub->ifindex) : NULL;
+		dev = ipv6_dev_find(net, &local.ipv6, dev);
+		if (!dev) {
+			err = -ENODEV;
+			goto err;
+		}
+		udp_conf.family = AF_INET6;
+		udp_conf.use_udp6_tx_checksums = true;
+		udp_conf.use_udp6_rx_checksums = true;
+		if (rmcast)
+			udp_conf.local_ip6 = in6addr_any;
+		else
+			udp_conf.local_ip6 = local.ipv6;
+		ub->ifindex = dev->ifindex;
+		b->encap_hlen = sizeof(struct ipv6hdr) + sizeof(struct udphdr);
+		b->mtu = 1280;
+#endif
+	} else {
+		err = -EAFNOSUPPORT;
+		goto err;
+	}
+	udp_conf.local_udp_port = local.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);
+
+	err = dst_cache_init(&ub->rcast.dst_cache, GFP_ATOMIC);
+	if (err)
+		goto free;
+
+	/**
+	 * The bcast media address port is used for all peers and the ip
+	 * is used if it's a multicast address.
+	 */
+	memcpy(&b->bcast_addr.value, &remote, sizeof(remote));
+	if (rmcast)
+		err = enable_mcast(ub, &remote);
+	else
+		err = tipc_udp_rcast_add(b, &remote);
+	if (err)
+		goto free;
+
+	return 0;
+
+free:
+	dst_cache_destroy(&ub->rcast.dst_cache);
+	udp_tunnel_sock_release(ub->ubsock);
+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);
+	struct udp_replicast *rcast, *tmp;
+
+	list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
+		dst_cache_destroy(&rcast->dst_cache);
+		list_del_rcu(&rcast->list);
+		kfree_rcu(rcast, rcu);
+	}
+
+	atomic_dec(&tipc_net(sock_net(ub->ubsock->sk))->wq_count);
+	dst_cache_destroy(&ub->rcast.dst_cache);
+	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 = rtnl_dereference(b->media_ptr);
+	if (!ub) {
+		pr_err("UDP bearer instance not found\n");
+		return;
+	}
+	sock_set_flag(ub->ubsock->sk, SOCK_DEAD);
+	RCU_INIT_POINTER(ub->bearer, NULL);
+
+	/* sock_release need to be done outside of rtnl lock */
+	atomic_inc(&tipc_net(sock_net(ub->ubsock->sk))->wq_count);
+	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,
+	.min_win	= TIPC_DEF_LINK_WIN,
+	.max_win	= TIPC_DEF_LINK_WIN,
+	.mtu		= TIPC_DEF_LINK_UDP_MTU,
+	.type_id	= TIPC_MEDIA_TYPE_UDP,
+	.hwaddr_len	= 0,
+	.name		= "udp"
+};