1 /* net/tipc/udp_media.c: IP bearer support for TIPC
3 * Copyright (c) 2015, Ericsson AB
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the names of the copyright holders nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
18 * Alternatively, this software may be distributed under the terms of the
19 * GNU General Public License ("GPL") version 2 as published by the Free
20 * Software Foundation.
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
23 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
26 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
35 #include <linux/socket.h>
37 #include <linux/udp.h>
38 #include <linux/inet.h>
39 #include <linux/inetdevice.h>
40 #include <linux/igmp.h>
41 #include <linux/kernel.h>
42 #include <linux/workqueue.h>
43 #include <linux/list.h>
46 #include <net/udp_tunnel.h>
47 #include <net/ipv6_stubs.h>
48 #include <linux/tipc_netlink.h>
56 /* IANA assigned UDP port */
57 #define UDP_PORT_DEFAULT 6118
59 #define UDP_MIN_HEADROOM 48
62 * struct udp_media_addr - IP/UDP addressing information
64 * This is the bearer level originating address used in neighbor discovery
65 * messages, and all fields should be in network byte order
67 struct udp_media_addr {
76 /* struct udp_replicast - container for UDP remote addresses */
77 struct udp_replicast {
78 struct udp_media_addr addr;
79 struct dst_cache dst_cache;
81 struct list_head list;
85 * struct udp_bearer - ip/udp bearer data structure
86 * @bearer: associated generic tipc bearer
87 * @ubsock: bearer associated socket
88 * @ifindex: local address scope
89 * @work: used to schedule deferred work on a bearer
92 struct tipc_bearer __rcu *bearer;
93 struct socket *ubsock;
95 struct work_struct work;
96 struct udp_replicast rcast;
99 static int tipc_udp_is_mcast_addr(struct udp_media_addr *addr)
101 if (ntohs(addr->proto) == ETH_P_IP)
102 return ipv4_is_multicast(addr->ipv4.s_addr);
103 #if IS_ENABLED(CONFIG_IPV6)
105 return ipv6_addr_is_multicast(&addr->ipv6);
110 /* udp_media_addr_set - convert a ip/udp address to a TIPC media address */
111 static void tipc_udp_media_addr_set(struct tipc_media_addr *addr,
112 struct udp_media_addr *ua)
114 memset(addr, 0, sizeof(struct tipc_media_addr));
115 addr->media_id = TIPC_MEDIA_TYPE_UDP;
116 memcpy(addr->value, ua, sizeof(struct udp_media_addr));
118 if (tipc_udp_is_mcast_addr(ua))
119 addr->broadcast = TIPC_BROADCAST_SUPPORT;
122 /* tipc_udp_addr2str - convert ip/udp address to string */
123 static int tipc_udp_addr2str(struct tipc_media_addr *a, char *buf, int size)
125 struct udp_media_addr *ua = (struct udp_media_addr *)&a->value;
127 if (ntohs(ua->proto) == ETH_P_IP)
128 snprintf(buf, size, "%pI4:%u", &ua->ipv4, ntohs(ua->port));
129 else if (ntohs(ua->proto) == ETH_P_IPV6)
130 snprintf(buf, size, "%pI6:%u", &ua->ipv6, ntohs(ua->port));
132 pr_err("Invalid UDP media address\n");
136 /* tipc_udp_msg2addr - extract an ip/udp address from a TIPC ndisc message */
137 static int tipc_udp_msg2addr(struct tipc_bearer *b, struct tipc_media_addr *a,
140 struct udp_media_addr *ua;
142 ua = (struct udp_media_addr *) (msg + TIPC_MEDIA_ADDR_OFFSET);
143 if (msg[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_UDP)
145 tipc_udp_media_addr_set(a, ua);
149 /* tipc_udp_addr2msg - write an ip/udp address to a TIPC ndisc message */
150 static int tipc_udp_addr2msg(char *msg, struct tipc_media_addr *a)
152 memset(msg, 0, TIPC_MEDIA_INFO_SIZE);
153 msg[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_UDP;
154 memcpy(msg + TIPC_MEDIA_ADDR_OFFSET, a->value,
155 sizeof(struct udp_media_addr));
159 /* tipc_send_msg - enqueue a send request */
160 static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
161 struct udp_bearer *ub, struct udp_media_addr *src,
162 struct udp_media_addr *dst, struct dst_cache *cache)
164 struct dst_entry *ndst = dst_cache_get(cache);
167 if (dst->proto == htons(ETH_P_IP)) {
168 struct rtable *rt = (struct rtable *)ndst;
172 .daddr = dst->ipv4.s_addr,
173 .saddr = src->ipv4.s_addr,
174 .flowi4_mark = skb->mark,
175 .flowi4_proto = IPPROTO_UDP
177 rt = ip_route_output_key(net, &fl);
182 dst_cache_set_ip4(cache, &rt->dst, fl.saddr);
185 ttl = ip4_dst_hoplimit(&rt->dst);
186 udp_tunnel_xmit_skb(rt, ub->ubsock->sk, skb, src->ipv4.s_addr,
187 dst->ipv4.s_addr, 0, ttl, 0, src->port,
188 dst->port, false, true);
189 #if IS_ENABLED(CONFIG_IPV6)
192 struct flowi6 fl6 = {
193 .flowi6_oif = ub->ifindex,
196 .flowi6_proto = IPPROTO_UDP
198 err = ipv6_stub->ipv6_dst_lookup(net, ub->ubsock->sk,
202 dst_cache_set_ip6(cache, ndst, &fl6.saddr);
204 ttl = ip6_dst_hoplimit(ndst);
205 err = udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, skb, NULL,
206 &src->ipv6, &dst->ipv6, 0, ttl, 0,
207 src->port, dst->port, false);
217 static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
218 struct tipc_bearer *b,
219 struct tipc_media_addr *addr)
221 struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
222 struct udp_media_addr *dst = (struct udp_media_addr *)&addr->value;
223 struct udp_replicast *rcast;
224 struct udp_bearer *ub;
227 if (skb_headroom(skb) < UDP_MIN_HEADROOM) {
228 err = pskb_expand_head(skb, UDP_MIN_HEADROOM, 0, GFP_ATOMIC);
233 skb_set_inner_protocol(skb, htons(ETH_P_TIPC));
234 ub = rcu_dereference(b->media_ptr);
240 if (addr->broadcast != TIPC_REPLICAST_SUPPORT)
241 return tipc_udp_xmit(net, skb, ub, src, dst,
242 &ub->rcast.dst_cache);
244 /* Replicast, send an skb to each configured IP address */
245 list_for_each_entry_rcu(rcast, &ub->rcast.list, list) {
246 struct sk_buff *_skb;
248 _skb = pskb_copy(skb, GFP_ATOMIC);
254 err = tipc_udp_xmit(net, _skb, ub, src, &rcast->addr,
265 static bool tipc_udp_is_known_peer(struct tipc_bearer *b,
266 struct udp_media_addr *addr)
268 struct udp_replicast *rcast, *tmp;
269 struct udp_bearer *ub;
271 ub = rcu_dereference_rtnl(b->media_ptr);
273 pr_err_ratelimited("UDP bearer instance not found\n");
277 list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
278 if (!memcmp(&rcast->addr, addr, sizeof(struct udp_media_addr)))
285 static int tipc_udp_rcast_add(struct tipc_bearer *b,
286 struct udp_media_addr *addr)
288 struct udp_replicast *rcast;
289 struct udp_bearer *ub;
291 ub = rcu_dereference_rtnl(b->media_ptr);
295 rcast = kmalloc(sizeof(*rcast), GFP_ATOMIC);
299 if (dst_cache_init(&rcast->dst_cache, GFP_ATOMIC)) {
304 memcpy(&rcast->addr, addr, sizeof(struct udp_media_addr));
306 if (ntohs(addr->proto) == ETH_P_IP)
307 pr_info("New replicast peer: %pI4\n", &rcast->addr.ipv4);
308 #if IS_ENABLED(CONFIG_IPV6)
309 else if (ntohs(addr->proto) == ETH_P_IPV6)
310 pr_info("New replicast peer: %pI6\n", &rcast->addr.ipv6);
312 b->bcast_addr.broadcast = TIPC_REPLICAST_SUPPORT;
313 list_add_rcu(&rcast->list, &ub->rcast.list);
317 static int tipc_udp_rcast_disc(struct tipc_bearer *b, struct sk_buff *skb)
319 struct udp_media_addr src = {0};
320 struct udp_media_addr *dst;
322 dst = (struct udp_media_addr *)&b->bcast_addr.value;
323 if (tipc_udp_is_mcast_addr(dst))
326 src.port = udp_hdr(skb)->source;
328 if (ip_hdr(skb)->version == 4) {
329 struct iphdr *iphdr = ip_hdr(skb);
331 src.proto = htons(ETH_P_IP);
332 src.ipv4.s_addr = iphdr->saddr;
333 if (ipv4_is_multicast(iphdr->daddr))
335 #if IS_ENABLED(CONFIG_IPV6)
336 } else if (ip_hdr(skb)->version == 6) {
337 struct ipv6hdr *iphdr = ipv6_hdr(skb);
339 src.proto = htons(ETH_P_IPV6);
340 src.ipv6 = iphdr->saddr;
341 if (ipv6_addr_is_multicast(&iphdr->daddr))
348 if (likely(tipc_udp_is_known_peer(b, &src)))
351 return tipc_udp_rcast_add(b, &src);
354 /* tipc_udp_recv - read data from bearer socket */
355 static int tipc_udp_recv(struct sock *sk, struct sk_buff *skb)
357 struct udp_bearer *ub;
358 struct tipc_bearer *b;
359 struct tipc_msg *hdr;
362 ub = rcu_dereference_sk_user_data(sk);
364 pr_err_ratelimited("Failed to get UDP bearer reference");
367 skb_pull(skb, sizeof(struct udphdr));
370 b = rcu_dereference(ub->bearer);
374 if (b && test_bit(0, &b->up)) {
375 tipc_rcv(sock_net(sk), skb, b);
379 if (unlikely(msg_user(hdr) == LINK_CONFIG)) {
380 err = tipc_udp_rcast_disc(b, skb);
390 static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
393 struct ip_mreqn mreqn;
394 struct sock *sk = ub->ubsock->sk;
396 if (ntohs(remote->proto) == ETH_P_IP) {
397 mreqn.imr_multiaddr = remote->ipv4;
398 mreqn.imr_ifindex = ub->ifindex;
399 err = ip_mc_join_group(sk, &mreqn);
400 #if IS_ENABLED(CONFIG_IPV6)
402 err = ipv6_stub->ipv6_sock_mc_join(sk, ub->ifindex,
409 static int __tipc_nl_add_udp_addr(struct sk_buff *skb,
410 struct udp_media_addr *addr, int nla_t)
412 if (ntohs(addr->proto) == ETH_P_IP) {
413 struct sockaddr_in ip4;
415 memset(&ip4, 0, sizeof(ip4));
416 ip4.sin_family = AF_INET;
417 ip4.sin_port = addr->port;
418 ip4.sin_addr.s_addr = addr->ipv4.s_addr;
419 if (nla_put(skb, nla_t, sizeof(ip4), &ip4))
422 #if IS_ENABLED(CONFIG_IPV6)
423 } else if (ntohs(addr->proto) == ETH_P_IPV6) {
424 struct sockaddr_in6 ip6;
426 memset(&ip6, 0, sizeof(ip6));
427 ip6.sin6_family = AF_INET6;
428 ip6.sin6_port = addr->port;
429 memcpy(&ip6.sin6_addr, &addr->ipv6, sizeof(struct in6_addr));
430 if (nla_put(skb, nla_t, sizeof(ip6), &ip6))
438 int tipc_udp_nl_dump_remoteip(struct sk_buff *skb, struct netlink_callback *cb)
440 u32 bid = cb->args[0];
441 u32 skip_cnt = cb->args[1];
442 u32 portid = NETLINK_CB(cb->skb).portid;
443 struct udp_replicast *rcast, *tmp;
444 struct tipc_bearer *b;
445 struct udp_bearer *ub;
450 if (!bid && !skip_cnt) {
451 struct net *net = sock_net(skb->sk);
452 struct nlattr *battrs[TIPC_NLA_BEARER_MAX + 1];
453 struct nlattr **attrs;
456 err = tipc_nlmsg_parse(cb->nlh, &attrs);
460 if (!attrs[TIPC_NLA_BEARER])
463 err = nla_parse_nested_deprecated(battrs, TIPC_NLA_BEARER_MAX,
464 attrs[TIPC_NLA_BEARER],
465 tipc_nl_bearer_policy, NULL);
469 if (!battrs[TIPC_NLA_BEARER_NAME])
472 bname = nla_data(battrs[TIPC_NLA_BEARER_NAME]);
475 b = tipc_bearer_find(net, bname);
482 struct net *net = sock_net(skb->sk);
483 struct tipc_net *tn = net_generic(net, tipc_net_id);
486 b = rtnl_dereference(tn->bearer_list[bid]);
493 ub = rtnl_dereference(b->media_ptr);
500 list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
504 hdr = genlmsg_put(skb, portid, cb->nlh->nlmsg_seq,
505 &tipc_genl_family, NLM_F_MULTI,
510 err = __tipc_nl_add_udp_addr(skb, &rcast->addr,
511 TIPC_NLA_UDP_REMOTE);
513 genlmsg_cancel(skb, hdr);
516 genlmsg_end(skb, hdr);
528 int tipc_udp_nl_add_bearer_data(struct tipc_nl_msg *msg, struct tipc_bearer *b)
530 struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
531 struct udp_media_addr *dst;
532 struct udp_bearer *ub;
535 ub = rtnl_dereference(b->media_ptr);
539 nest = nla_nest_start_noflag(msg->skb, TIPC_NLA_BEARER_UDP_OPTS);
543 if (__tipc_nl_add_udp_addr(msg->skb, src, TIPC_NLA_UDP_LOCAL))
546 dst = (struct udp_media_addr *)&b->bcast_addr.value;
547 if (__tipc_nl_add_udp_addr(msg->skb, dst, TIPC_NLA_UDP_REMOTE))
550 if (!list_empty(&ub->rcast.list)) {
551 if (nla_put_flag(msg->skb, TIPC_NLA_UDP_MULTI_REMOTEIP))
555 nla_nest_end(msg->skb, nest);
558 nla_nest_cancel(msg->skb, nest);
563 * tipc_parse_udp_addr - build udp media address from netlink data
564 * @nlattr: netlink attribute containing sockaddr storage aligned address
565 * @addr: tipc media address to fill with address, port and protocol type
566 * @scope_id: IPv6 scope id pointer, not NULL indicates it's required
569 static int tipc_parse_udp_addr(struct nlattr *nla, struct udp_media_addr *addr,
572 struct sockaddr_storage sa;
574 nla_memcpy(&sa, nla, sizeof(sa));
575 if (sa.ss_family == AF_INET) {
576 struct sockaddr_in *ip4 = (struct sockaddr_in *)&sa;
578 addr->proto = htons(ETH_P_IP);
579 addr->port = ip4->sin_port;
580 addr->ipv4.s_addr = ip4->sin_addr.s_addr;
583 #if IS_ENABLED(CONFIG_IPV6)
584 } else if (sa.ss_family == AF_INET6) {
585 struct sockaddr_in6 *ip6 = (struct sockaddr_in6 *)&sa;
587 addr->proto = htons(ETH_P_IPV6);
588 addr->port = ip6->sin6_port;
589 memcpy(&addr->ipv6, &ip6->sin6_addr, sizeof(struct in6_addr));
591 /* Scope ID is only interesting for local addresses */
595 atype = ipv6_addr_type(&ip6->sin6_addr);
596 if (__ipv6_addr_needs_scope_id(atype) &&
597 !ip6->sin6_scope_id) {
601 *scope_id = ip6->sin6_scope_id ? : 0;
607 return -EADDRNOTAVAIL;
610 int tipc_udp_nl_bearer_add(struct tipc_bearer *b, struct nlattr *attr)
613 struct udp_media_addr addr = {0};
614 struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
615 struct udp_media_addr *dst;
617 if (nla_parse_nested_deprecated(opts, TIPC_NLA_UDP_MAX, attr, tipc_nl_udp_policy, NULL))
620 if (!opts[TIPC_NLA_UDP_REMOTE])
623 err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_REMOTE], &addr, NULL);
627 dst = (struct udp_media_addr *)&b->bcast_addr.value;
628 if (tipc_udp_is_mcast_addr(dst)) {
629 pr_err("Can't add remote ip to TIPC UDP multicast bearer\n");
633 if (tipc_udp_is_known_peer(b, &addr))
636 return tipc_udp_rcast_add(b, &addr);
640 * tipc_udp_enable - callback to create a new udp bearer instance
641 * @net: network namespace
642 * @b: pointer to generic tipc_bearer
643 * @attrs: netlink bearer configuration
645 * validate the bearer parameters and initialize the udp bearer
646 * rtnl_lock should be held
648 static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
649 struct nlattr *attrs[])
652 struct udp_bearer *ub;
653 struct udp_media_addr remote = {0};
654 struct udp_media_addr local = {0};
655 struct udp_port_cfg udp_conf = {0};
656 struct udp_tunnel_sock_cfg tuncfg = {NULL};
657 struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
658 u8 node_id[NODE_ID_LEN] = {0,};
661 ub = kzalloc(sizeof(*ub), GFP_ATOMIC);
665 INIT_LIST_HEAD(&ub->rcast.list);
667 if (!attrs[TIPC_NLA_BEARER_UDP_OPTS])
670 if (nla_parse_nested_deprecated(opts, TIPC_NLA_UDP_MAX, attrs[TIPC_NLA_BEARER_UDP_OPTS], tipc_nl_udp_policy, NULL))
673 if (!opts[TIPC_NLA_UDP_LOCAL] || !opts[TIPC_NLA_UDP_REMOTE]) {
674 pr_err("Invalid UDP bearer configuration");
679 err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_LOCAL], &local,
684 err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_REMOTE], &remote, NULL);
688 if (remote.proto != local.proto) {
693 /* Checking remote ip address */
694 rmcast = tipc_udp_is_mcast_addr(&remote);
696 /* Autoconfigure own node identity if needed */
697 if (!tipc_own_id(net)) {
698 memcpy(node_id, local.ipv6.in6_u.u6_addr8, 16);
699 tipc_net_init(net, node_id, 0);
701 if (!tipc_own_id(net)) {
702 pr_warn("Failed to set node id, please configure manually\n");
707 b->bcast_addr.media_id = TIPC_MEDIA_TYPE_UDP;
708 b->bcast_addr.broadcast = TIPC_BROADCAST_SUPPORT;
709 rcu_assign_pointer(b->media_ptr, ub);
710 rcu_assign_pointer(ub->bearer, b);
711 tipc_udp_media_addr_set(&b->addr, &local);
712 if (local.proto == htons(ETH_P_IP)) {
713 struct net_device *dev;
715 dev = __ip_dev_find(net, local.ipv4.s_addr, false);
720 udp_conf.family = AF_INET;
722 /* Switch to use ANY to receive packets from group */
724 udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
726 udp_conf.local_ip.s_addr = local.ipv4.s_addr;
727 udp_conf.use_udp_checksums = false;
728 ub->ifindex = dev->ifindex;
729 if (tipc_mtu_bad(dev, sizeof(struct iphdr) +
730 sizeof(struct udphdr))) {
734 b->mtu = b->media->mtu;
735 #if IS_ENABLED(CONFIG_IPV6)
736 } else if (local.proto == htons(ETH_P_IPV6)) {
737 udp_conf.family = AF_INET6;
738 udp_conf.use_udp6_tx_checksums = true;
739 udp_conf.use_udp6_rx_checksums = true;
741 udp_conf.local_ip6 = in6addr_any;
743 udp_conf.local_ip6 = local.ipv6;
750 udp_conf.local_udp_port = local.port;
751 err = udp_sock_create(net, &udp_conf, &ub->ubsock);
754 tuncfg.sk_user_data = ub;
755 tuncfg.encap_type = 1;
756 tuncfg.encap_rcv = tipc_udp_recv;
757 tuncfg.encap_destroy = NULL;
758 setup_udp_tunnel_sock(net, ub->ubsock, &tuncfg);
760 err = dst_cache_init(&ub->rcast.dst_cache, GFP_ATOMIC);
765 * The bcast media address port is used for all peers and the ip
766 * is used if it's a multicast address.
768 memcpy(&b->bcast_addr.value, &remote, sizeof(remote));
770 err = enable_mcast(ub, &remote);
772 err = tipc_udp_rcast_add(b, &remote);
779 dst_cache_destroy(&ub->rcast.dst_cache);
780 udp_tunnel_sock_release(ub->ubsock);
786 /* cleanup_bearer - break the socket/bearer association */
787 static void cleanup_bearer(struct work_struct *work)
789 struct udp_bearer *ub = container_of(work, struct udp_bearer, work);
790 struct udp_replicast *rcast, *tmp;
792 list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
793 dst_cache_destroy(&rcast->dst_cache);
794 list_del_rcu(&rcast->list);
795 kfree_rcu(rcast, rcu);
798 dst_cache_destroy(&ub->rcast.dst_cache);
799 udp_tunnel_sock_release(ub->ubsock);
804 /* tipc_udp_disable - detach bearer from socket */
805 static void tipc_udp_disable(struct tipc_bearer *b)
807 struct udp_bearer *ub;
809 ub = rtnl_dereference(b->media_ptr);
811 pr_err("UDP bearer instance not found\n");
814 sock_set_flag(ub->ubsock->sk, SOCK_DEAD);
815 RCU_INIT_POINTER(ub->bearer, NULL);
817 /* sock_release need to be done outside of rtnl lock */
818 INIT_WORK(&ub->work, cleanup_bearer);
819 schedule_work(&ub->work);
822 struct tipc_media udp_media_info = {
823 .send_msg = tipc_udp_send_msg,
824 .enable_media = tipc_udp_enable,
825 .disable_media = tipc_udp_disable,
826 .addr2str = tipc_udp_addr2str,
827 .addr2msg = tipc_udp_addr2msg,
828 .msg2addr = tipc_udp_msg2addr,
829 .priority = TIPC_DEF_LINK_PRI,
830 .tolerance = TIPC_DEF_LINK_TOL,
831 .window = TIPC_DEF_LINK_WIN,
832 .mtu = TIPC_DEF_LINK_UDP_MTU,
833 .type_id = TIPC_MEDIA_TYPE_UDP,