net/tipc/udp_media.c - linux - Git at Google

 /* 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"

 /* 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;
 		if (tipc_mtu_bad(dev, sizeof(struct iphdr) +
 				      sizeof(struct udphdr))) {
 			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->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);
 	}

 	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 */
 	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"
 };
	/* 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"

	/* 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;
	if (tipc_mtu_bad(dev, sizeof(struct iphdr) +
	sizeof(struct udphdr))) {
	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->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);
	}

	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 */
	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"
	};