xref: /linux/net/tipc/udp_media.c (revision 109d59b900e78834c66657dd4748fcedb9a1fe8d)
1 /* net/tipc/udp_media.c: IP bearer support for TIPC
2  *
3  * Copyright (c) 2015, Ericsson AB
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions are met:
8  *
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.
17  *
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.
21  *
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.
33  */
34 
35 #include <linux/socket.h>
36 #include <linux/ip.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>
44 #include <net/sock.h>
45 #include <net/ip.h>
46 #include <net/udp_tunnel.h>
47 #include <net/addrconf.h>
48 #include <linux/tipc_netlink.h>
49 #include "core.h"
50 #include "bearer.h"
51 #include "netlink.h"
52 #include "msg.h"
53 
54 /* IANA assigned UDP port */
55 #define UDP_PORT_DEFAULT	6118
56 
57 #define UDP_MIN_HEADROOM        48
58 
59 /**
60  * struct udp_media_addr - IP/UDP addressing information
61  *
62  * This is the bearer level originating address used in neighbor discovery
63  * messages, and all fields should be in network byte order
64  */
65 struct udp_media_addr {
66 	__be16	proto;
67 	__be16	port;
68 	union {
69 		struct in_addr ipv4;
70 		struct in6_addr ipv6;
71 	};
72 };
73 
74 /* struct udp_replicast - container for UDP remote addresses */
75 struct udp_replicast {
76 	struct udp_media_addr addr;
77 	struct rcu_head rcu;
78 	struct list_head list;
79 };
80 
81 /**
82  * struct udp_bearer - ip/udp bearer data structure
83  * @bearer:	associated generic tipc bearer
84  * @ubsock:	bearer associated socket
85  * @ifindex:	local address scope
86  * @work:	used to schedule deferred work on a bearer
87  */
88 struct udp_bearer {
89 	struct tipc_bearer __rcu *bearer;
90 	struct socket *ubsock;
91 	u32 ifindex;
92 	struct work_struct work;
93 	struct udp_replicast rcast;
94 };
95 
96 static int tipc_udp_is_mcast_addr(struct udp_media_addr *addr)
97 {
98 	if (ntohs(addr->proto) == ETH_P_IP)
99 		return ipv4_is_multicast(addr->ipv4.s_addr);
100 #if IS_ENABLED(CONFIG_IPV6)
101 	else
102 		return ipv6_addr_is_multicast(&addr->ipv6);
103 #endif
104 	return 0;
105 }
106 
107 /* udp_media_addr_set - convert a ip/udp address to a TIPC media address */
108 static void tipc_udp_media_addr_set(struct tipc_media_addr *addr,
109 				    struct udp_media_addr *ua)
110 {
111 	memset(addr, 0, sizeof(struct tipc_media_addr));
112 	addr->media_id = TIPC_MEDIA_TYPE_UDP;
113 	memcpy(addr->value, ua, sizeof(struct udp_media_addr));
114 
115 	if (tipc_udp_is_mcast_addr(ua))
116 		addr->broadcast = TIPC_BROADCAST_SUPPORT;
117 }
118 
119 /* tipc_udp_addr2str - convert ip/udp address to string */
120 static int tipc_udp_addr2str(struct tipc_media_addr *a, char *buf, int size)
121 {
122 	struct udp_media_addr *ua = (struct udp_media_addr *)&a->value;
123 
124 	if (ntohs(ua->proto) == ETH_P_IP)
125 		snprintf(buf, size, "%pI4:%u", &ua->ipv4, ntohs(ua->port));
126 	else if (ntohs(ua->proto) == ETH_P_IPV6)
127 		snprintf(buf, size, "%pI6:%u", &ua->ipv6, ntohs(ua->port));
128 	else
129 		pr_err("Invalid UDP media address\n");
130 	return 0;
131 }
132 
133 /* tipc_udp_msg2addr - extract an ip/udp address from a TIPC ndisc message */
134 static int tipc_udp_msg2addr(struct tipc_bearer *b, struct tipc_media_addr *a,
135 			     char *msg)
136 {
137 	struct udp_media_addr *ua;
138 
139 	ua = (struct udp_media_addr *) (msg + TIPC_MEDIA_ADDR_OFFSET);
140 	if (msg[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_UDP)
141 		return -EINVAL;
142 	tipc_udp_media_addr_set(a, ua);
143 	return 0;
144 }
145 
146 /* tipc_udp_addr2msg - write an ip/udp address to a TIPC ndisc message */
147 static int tipc_udp_addr2msg(char *msg, struct tipc_media_addr *a)
148 {
149 	memset(msg, 0, TIPC_MEDIA_INFO_SIZE);
150 	msg[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_UDP;
151 	memcpy(msg + TIPC_MEDIA_ADDR_OFFSET, a->value,
152 	       sizeof(struct udp_media_addr));
153 	return 0;
154 }
155 
156 /* tipc_send_msg - enqueue a send request */
157 static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
158 			 struct udp_bearer *ub, struct udp_media_addr *src,
159 			 struct udp_media_addr *dst)
160 {
161 	int ttl, err = 0;
162 	struct rtable *rt;
163 
164 	if (dst->proto == htons(ETH_P_IP)) {
165 		struct flowi4 fl = {
166 			.daddr = dst->ipv4.s_addr,
167 			.saddr = src->ipv4.s_addr,
168 			.flowi4_mark = skb->mark,
169 			.flowi4_proto = IPPROTO_UDP
170 		};
171 		rt = ip_route_output_key(net, &fl);
172 		if (IS_ERR(rt)) {
173 			err = PTR_ERR(rt);
174 			goto tx_error;
175 		}
176 
177 		skb->dev = rt->dst.dev;
178 		ttl = ip4_dst_hoplimit(&rt->dst);
179 		udp_tunnel_xmit_skb(rt, ub->ubsock->sk, skb, src->ipv4.s_addr,
180 				    dst->ipv4.s_addr, 0, ttl, 0, src->port,
181 				    dst->port, false, true);
182 #if IS_ENABLED(CONFIG_IPV6)
183 	} else {
184 		struct dst_entry *ndst;
185 		struct flowi6 fl6 = {
186 			.flowi6_oif = ub->ifindex,
187 			.daddr = dst->ipv6,
188 			.saddr = src->ipv6,
189 			.flowi6_proto = IPPROTO_UDP
190 		};
191 		err = ipv6_stub->ipv6_dst_lookup(net, ub->ubsock->sk, &ndst,
192 						 &fl6);
193 		if (err)
194 			goto tx_error;
195 		ttl = ip6_dst_hoplimit(ndst);
196 		err = udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, skb,
197 					   ndst->dev, &src->ipv6,
198 					   &dst->ipv6, 0, ttl, 0, src->port,
199 					   dst->port, false);
200 #endif
201 	}
202 	return err;
203 
204 tx_error:
205 	kfree_skb(skb);
206 	return err;
207 }
208 
209 static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
210 			     struct tipc_bearer *b,
211 			     struct tipc_media_addr *addr)
212 {
213 	struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
214 	struct udp_media_addr *dst = (struct udp_media_addr *)&addr->value;
215 	struct udp_replicast *rcast;
216 	struct udp_bearer *ub;
217 	int err = 0;
218 
219 	if (skb_headroom(skb) < UDP_MIN_HEADROOM) {
220 		err = pskb_expand_head(skb, UDP_MIN_HEADROOM, 0, GFP_ATOMIC);
221 		if (err)
222 			goto out;
223 	}
224 
225 	skb_set_inner_protocol(skb, htons(ETH_P_TIPC));
226 	ub = rcu_dereference_rtnl(b->media_ptr);
227 	if (!ub) {
228 		err = -ENODEV;
229 		goto out;
230 	}
231 
232 	if (addr->broadcast != TIPC_REPLICAST_SUPPORT)
233 		return tipc_udp_xmit(net, skb, ub, src, dst);
234 
235 	/* Replicast, send an skb to each configured IP address */
236 	list_for_each_entry_rcu(rcast, &ub->rcast.list, list) {
237 		struct sk_buff *_skb;
238 
239 		_skb = pskb_copy(skb, GFP_ATOMIC);
240 		if (!_skb) {
241 			err = -ENOMEM;
242 			goto out;
243 		}
244 
245 		err = tipc_udp_xmit(net, _skb, ub, src, &rcast->addr);
246 		if (err) {
247 			kfree_skb(_skb);
248 			goto out;
249 		}
250 	}
251 	err = 0;
252 out:
253 	kfree_skb(skb);
254 	return err;
255 }
256 
257 static bool tipc_udp_is_known_peer(struct tipc_bearer *b,
258 				   struct udp_media_addr *addr)
259 {
260 	struct udp_replicast *rcast, *tmp;
261 	struct udp_bearer *ub;
262 
263 	ub = rcu_dereference_rtnl(b->media_ptr);
264 	if (!ub) {
265 		pr_err_ratelimited("UDP bearer instance not found\n");
266 		return false;
267 	}
268 
269 	list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
270 		if (!memcmp(&rcast->addr, addr, sizeof(struct udp_media_addr)))
271 			return true;
272 	}
273 
274 	return false;
275 }
276 
277 static int tipc_udp_rcast_add(struct tipc_bearer *b,
278 			      struct udp_media_addr *addr)
279 {
280 	struct udp_replicast *rcast;
281 	struct udp_bearer *ub;
282 
283 	ub = rcu_dereference_rtnl(b->media_ptr);
284 	if (!ub)
285 		return -ENODEV;
286 
287 	rcast = kmalloc(sizeof(*rcast), GFP_ATOMIC);
288 	if (!rcast)
289 		return -ENOMEM;
290 
291 	memcpy(&rcast->addr, addr, sizeof(struct udp_media_addr));
292 
293 	if (ntohs(addr->proto) == ETH_P_IP)
294 		pr_info("New replicast peer: %pI4\n", &rcast->addr.ipv4);
295 #if IS_ENABLED(CONFIG_IPV6)
296 	else if (ntohs(addr->proto) == ETH_P_IPV6)
297 		pr_info("New replicast peer: %pI6\n", &rcast->addr.ipv6);
298 #endif
299 	b->bcast_addr.broadcast = TIPC_REPLICAST_SUPPORT;
300 	list_add_rcu(&rcast->list, &ub->rcast.list);
301 	return 0;
302 }
303 
304 static int tipc_udp_rcast_disc(struct tipc_bearer *b, struct sk_buff *skb)
305 {
306 	struct udp_media_addr src = {0};
307 	struct udp_media_addr *dst;
308 
309 	dst = (struct udp_media_addr *)&b->bcast_addr.value;
310 	if (tipc_udp_is_mcast_addr(dst))
311 		return 0;
312 
313 	src.port = udp_hdr(skb)->source;
314 
315 	if (ip_hdr(skb)->version == 4) {
316 		struct iphdr *iphdr = ip_hdr(skb);
317 
318 		src.proto = htons(ETH_P_IP);
319 		src.ipv4.s_addr = iphdr->saddr;
320 		if (ipv4_is_multicast(iphdr->daddr))
321 			return 0;
322 #if IS_ENABLED(CONFIG_IPV6)
323 	} else if (ip_hdr(skb)->version == 6) {
324 		struct ipv6hdr *iphdr = ipv6_hdr(skb);
325 
326 		src.proto = htons(ETH_P_IPV6);
327 		src.ipv6 = iphdr->saddr;
328 		if (ipv6_addr_is_multicast(&iphdr->daddr))
329 			return 0;
330 #endif
331 	} else {
332 		return 0;
333 	}
334 
335 	if (likely(tipc_udp_is_known_peer(b, &src)))
336 		return 0;
337 
338 	return tipc_udp_rcast_add(b, &src);
339 }
340 
341 /* tipc_udp_recv - read data from bearer socket */
342 static int tipc_udp_recv(struct sock *sk, struct sk_buff *skb)
343 {
344 	struct udp_bearer *ub;
345 	struct tipc_bearer *b;
346 	struct tipc_msg *hdr;
347 	int err;
348 
349 	ub = rcu_dereference_sk_user_data(sk);
350 	if (!ub) {
351 		pr_err_ratelimited("Failed to get UDP bearer reference");
352 		goto out;
353 	}
354 	skb_pull(skb, sizeof(struct udphdr));
355 	hdr = buf_msg(skb);
356 
357 	rcu_read_lock();
358 	b = rcu_dereference_rtnl(ub->bearer);
359 	if (!b)
360 		goto rcu_out;
361 
362 	if (b && test_bit(0, &b->up)) {
363 		tipc_rcv(sock_net(sk), skb, b);
364 		rcu_read_unlock();
365 		return 0;
366 	}
367 
368 	if (unlikely(msg_user(hdr) == LINK_CONFIG)) {
369 		err = tipc_udp_rcast_disc(b, skb);
370 		if (err)
371 			goto rcu_out;
372 	}
373 
374 rcu_out:
375 	rcu_read_unlock();
376 out:
377 	kfree_skb(skb);
378 	return 0;
379 }
380 
381 static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
382 {
383 	int err = 0;
384 	struct ip_mreqn mreqn;
385 	struct sock *sk = ub->ubsock->sk;
386 
387 	if (ntohs(remote->proto) == ETH_P_IP) {
388 		mreqn.imr_multiaddr = remote->ipv4;
389 		mreqn.imr_ifindex = ub->ifindex;
390 		err = ip_mc_join_group(sk, &mreqn);
391 #if IS_ENABLED(CONFIG_IPV6)
392 	} else {
393 		err = ipv6_stub->ipv6_sock_mc_join(sk, ub->ifindex,
394 						   &remote->ipv6);
395 #endif
396 	}
397 	return err;
398 }
399 
400 static int __tipc_nl_add_udp_addr(struct sk_buff *skb,
401 				  struct udp_media_addr *addr, int nla_t)
402 {
403 	if (ntohs(addr->proto) == ETH_P_IP) {
404 		struct sockaddr_in ip4;
405 
406 		memset(&ip4, 0, sizeof(ip4));
407 		ip4.sin_family = AF_INET;
408 		ip4.sin_port = addr->port;
409 		ip4.sin_addr.s_addr = addr->ipv4.s_addr;
410 		if (nla_put(skb, nla_t, sizeof(ip4), &ip4))
411 			return -EMSGSIZE;
412 
413 #if IS_ENABLED(CONFIG_IPV6)
414 	} else if (ntohs(addr->proto) == ETH_P_IPV6) {
415 		struct sockaddr_in6 ip6;
416 
417 		memset(&ip6, 0, sizeof(ip6));
418 		ip6.sin6_family = AF_INET6;
419 		ip6.sin6_port  = addr->port;
420 		memcpy(&ip6.sin6_addr, &addr->ipv6, sizeof(struct in6_addr));
421 		if (nla_put(skb, nla_t, sizeof(ip6), &ip6))
422 			return -EMSGSIZE;
423 #endif
424 	}
425 
426 	return 0;
427 }
428 
429 int tipc_udp_nl_dump_remoteip(struct sk_buff *skb, struct netlink_callback *cb)
430 {
431 	u32 bid = cb->args[0];
432 	u32 skip_cnt = cb->args[1];
433 	u32 portid = NETLINK_CB(cb->skb).portid;
434 	struct udp_replicast *rcast, *tmp;
435 	struct tipc_bearer *b;
436 	struct udp_bearer *ub;
437 	void *hdr;
438 	int err;
439 	int i;
440 
441 	if (!bid && !skip_cnt) {
442 		struct net *net = sock_net(skb->sk);
443 		struct nlattr *battrs[TIPC_NLA_BEARER_MAX + 1];
444 		struct nlattr **attrs;
445 		char *bname;
446 
447 		err = tipc_nlmsg_parse(cb->nlh, &attrs);
448 		if (err)
449 			return err;
450 
451 		if (!attrs[TIPC_NLA_BEARER])
452 			return -EINVAL;
453 
454 		err = nla_parse_nested(battrs, TIPC_NLA_BEARER_MAX,
455 				       attrs[TIPC_NLA_BEARER],
456 				       tipc_nl_bearer_policy, NULL);
457 		if (err)
458 			return err;
459 
460 		if (!battrs[TIPC_NLA_BEARER_NAME])
461 			return -EINVAL;
462 
463 		bname = nla_data(battrs[TIPC_NLA_BEARER_NAME]);
464 
465 		rtnl_lock();
466 		b = tipc_bearer_find(net, bname);
467 		if (!b) {
468 			rtnl_unlock();
469 			return -EINVAL;
470 		}
471 		bid = b->identity;
472 	} else {
473 		struct net *net = sock_net(skb->sk);
474 		struct tipc_net *tn = net_generic(net, tipc_net_id);
475 
476 		rtnl_lock();
477 		b = rtnl_dereference(tn->bearer_list[bid]);
478 		if (!b) {
479 			rtnl_unlock();
480 			return -EINVAL;
481 		}
482 	}
483 
484 	ub = rcu_dereference_rtnl(b->media_ptr);
485 	if (!ub) {
486 		rtnl_unlock();
487 		return -EINVAL;
488 	}
489 
490 	i = 0;
491 	list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
492 		if (i < skip_cnt)
493 			goto count;
494 
495 		hdr = genlmsg_put(skb, portid, cb->nlh->nlmsg_seq,
496 				  &tipc_genl_family, NLM_F_MULTI,
497 				  TIPC_NL_BEARER_GET);
498 		if (!hdr)
499 			goto done;
500 
501 		err = __tipc_nl_add_udp_addr(skb, &rcast->addr,
502 					     TIPC_NLA_UDP_REMOTE);
503 		if (err) {
504 			genlmsg_cancel(skb, hdr);
505 			goto done;
506 		}
507 		genlmsg_end(skb, hdr);
508 count:
509 		i++;
510 	}
511 done:
512 	rtnl_unlock();
513 	cb->args[0] = bid;
514 	cb->args[1] = i;
515 
516 	return skb->len;
517 }
518 
519 int tipc_udp_nl_add_bearer_data(struct tipc_nl_msg *msg, struct tipc_bearer *b)
520 {
521 	struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
522 	struct udp_media_addr *dst;
523 	struct udp_bearer *ub;
524 	struct nlattr *nest;
525 
526 	ub = rcu_dereference_rtnl(b->media_ptr);
527 	if (!ub)
528 		return -ENODEV;
529 
530 	nest = nla_nest_start(msg->skb, TIPC_NLA_BEARER_UDP_OPTS);
531 	if (!nest)
532 		goto msg_full;
533 
534 	if (__tipc_nl_add_udp_addr(msg->skb, src, TIPC_NLA_UDP_LOCAL))
535 		goto msg_full;
536 
537 	dst = (struct udp_media_addr *)&b->bcast_addr.value;
538 	if (__tipc_nl_add_udp_addr(msg->skb, dst, TIPC_NLA_UDP_REMOTE))
539 		goto msg_full;
540 
541 	if (!list_empty(&ub->rcast.list)) {
542 		if (nla_put_flag(msg->skb, TIPC_NLA_UDP_MULTI_REMOTEIP))
543 			goto msg_full;
544 	}
545 
546 	nla_nest_end(msg->skb, nest);
547 	return 0;
548 msg_full:
549 	nla_nest_cancel(msg->skb, nest);
550 	return -EMSGSIZE;
551 }
552 
553 /**
554  * tipc_parse_udp_addr - build udp media address from netlink data
555  * @nlattr:	netlink attribute containing sockaddr storage aligned address
556  * @addr:	tipc media address to fill with address, port and protocol type
557  * @scope_id:	IPv6 scope id pointer, not NULL indicates it's required
558  */
559 
560 static int tipc_parse_udp_addr(struct nlattr *nla, struct udp_media_addr *addr,
561 			       u32 *scope_id)
562 {
563 	struct sockaddr_storage sa;
564 
565 	nla_memcpy(&sa, nla, sizeof(sa));
566 	if (sa.ss_family == AF_INET) {
567 		struct sockaddr_in *ip4 = (struct sockaddr_in *)&sa;
568 
569 		addr->proto = htons(ETH_P_IP);
570 		addr->port = ip4->sin_port;
571 		addr->ipv4.s_addr = ip4->sin_addr.s_addr;
572 		return 0;
573 
574 #if IS_ENABLED(CONFIG_IPV6)
575 	} else if (sa.ss_family == AF_INET6) {
576 		struct sockaddr_in6 *ip6 = (struct sockaddr_in6 *)&sa;
577 
578 		addr->proto = htons(ETH_P_IPV6);
579 		addr->port = ip6->sin6_port;
580 		memcpy(&addr->ipv6, &ip6->sin6_addr, sizeof(struct in6_addr));
581 
582 		/* Scope ID is only interesting for local addresses */
583 		if (scope_id) {
584 			int atype;
585 
586 			atype = ipv6_addr_type(&ip6->sin6_addr);
587 			if (__ipv6_addr_needs_scope_id(atype) &&
588 			    !ip6->sin6_scope_id) {
589 				return -EINVAL;
590 			}
591 
592 			*scope_id = ip6->sin6_scope_id ? : 0;
593 		}
594 
595 		return 0;
596 #endif
597 	}
598 	return -EADDRNOTAVAIL;
599 }
600 
601 int tipc_udp_nl_bearer_add(struct tipc_bearer *b, struct nlattr *attr)
602 {
603 	int err;
604 	struct udp_media_addr addr = {0};
605 	struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
606 	struct udp_media_addr *dst;
607 
608 	if (nla_parse_nested(opts, TIPC_NLA_UDP_MAX, attr,
609 			     tipc_nl_udp_policy, NULL))
610 		return -EINVAL;
611 
612 	if (!opts[TIPC_NLA_UDP_REMOTE])
613 		return -EINVAL;
614 
615 	err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_REMOTE], &addr, NULL);
616 	if (err)
617 		return err;
618 
619 	dst = (struct udp_media_addr *)&b->bcast_addr.value;
620 	if (tipc_udp_is_mcast_addr(dst)) {
621 		pr_err("Can't add remote ip to TIPC UDP multicast bearer\n");
622 		return -EINVAL;
623 	}
624 
625 	if (tipc_udp_is_known_peer(b, &addr))
626 		return 0;
627 
628 	return tipc_udp_rcast_add(b, &addr);
629 }
630 
631 /**
632  * tipc_udp_enable - callback to create a new udp bearer instance
633  * @net:	network namespace
634  * @b:		pointer to generic tipc_bearer
635  * @attrs:	netlink bearer configuration
636  *
637  * validate the bearer parameters and initialize the udp bearer
638  * rtnl_lock should be held
639  */
640 static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
641 			   struct nlattr *attrs[])
642 {
643 	int err = -EINVAL;
644 	struct udp_bearer *ub;
645 	struct udp_media_addr remote = {0};
646 	struct udp_media_addr local = {0};
647 	struct udp_port_cfg udp_conf = {0};
648 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
649 	struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
650 
651 	ub = kzalloc(sizeof(*ub), GFP_ATOMIC);
652 	if (!ub)
653 		return -ENOMEM;
654 
655 	INIT_LIST_HEAD(&ub->rcast.list);
656 
657 	if (!attrs[TIPC_NLA_BEARER_UDP_OPTS])
658 		goto err;
659 
660 	if (nla_parse_nested(opts, TIPC_NLA_UDP_MAX,
661 			     attrs[TIPC_NLA_BEARER_UDP_OPTS],
662 			     tipc_nl_udp_policy, NULL))
663 		goto err;
664 
665 	if (!opts[TIPC_NLA_UDP_LOCAL] || !opts[TIPC_NLA_UDP_REMOTE]) {
666 		pr_err("Invalid UDP bearer configuration");
667 		err = -EINVAL;
668 		goto err;
669 	}
670 
671 	err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_LOCAL], &local,
672 				  &ub->ifindex);
673 	if (err)
674 		goto err;
675 
676 	err = tipc_parse_udp_addr(opts[TIPC_NLA_UDP_REMOTE], &remote, NULL);
677 	if (err)
678 		goto err;
679 
680 	b->bcast_addr.media_id = TIPC_MEDIA_TYPE_UDP;
681 	b->bcast_addr.broadcast = TIPC_BROADCAST_SUPPORT;
682 	rcu_assign_pointer(b->media_ptr, ub);
683 	rcu_assign_pointer(ub->bearer, b);
684 	tipc_udp_media_addr_set(&b->addr, &local);
685 	if (local.proto == htons(ETH_P_IP)) {
686 		struct net_device *dev;
687 
688 		dev = __ip_dev_find(net, local.ipv4.s_addr, false);
689 		if (!dev) {
690 			err = -ENODEV;
691 			goto err;
692 		}
693 		udp_conf.family = AF_INET;
694 		udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
695 		udp_conf.use_udp_checksums = false;
696 		ub->ifindex = dev->ifindex;
697 		if (tipc_mtu_bad(dev, sizeof(struct iphdr) +
698 				      sizeof(struct udphdr))) {
699 			err = -EINVAL;
700 			goto err;
701 		}
702 		b->mtu = dev->mtu - sizeof(struct iphdr)
703 			- sizeof(struct udphdr);
704 #if IS_ENABLED(CONFIG_IPV6)
705 	} else if (local.proto == htons(ETH_P_IPV6)) {
706 		udp_conf.family = AF_INET6;
707 		udp_conf.use_udp6_tx_checksums = true;
708 		udp_conf.use_udp6_rx_checksums = true;
709 		udp_conf.local_ip6 = in6addr_any;
710 		b->mtu = 1280;
711 #endif
712 	} else {
713 		err = -EAFNOSUPPORT;
714 		goto err;
715 	}
716 	udp_conf.local_udp_port = local.port;
717 	err = udp_sock_create(net, &udp_conf, &ub->ubsock);
718 	if (err)
719 		goto err;
720 	tuncfg.sk_user_data = ub;
721 	tuncfg.encap_type = 1;
722 	tuncfg.encap_rcv = tipc_udp_recv;
723 	tuncfg.encap_destroy = NULL;
724 	setup_udp_tunnel_sock(net, ub->ubsock, &tuncfg);
725 
726 	/**
727 	 * The bcast media address port is used for all peers and the ip
728 	 * is used if it's a multicast address.
729 	 */
730 	memcpy(&b->bcast_addr.value, &remote, sizeof(remote));
731 	if (tipc_udp_is_mcast_addr(&remote))
732 		err = enable_mcast(ub, &remote);
733 	else
734 		err = tipc_udp_rcast_add(b, &remote);
735 	if (err)
736 		goto err;
737 
738 	return 0;
739 err:
740 	if (ub->ubsock)
741 		udp_tunnel_sock_release(ub->ubsock);
742 	kfree(ub);
743 	return err;
744 }
745 
746 /* cleanup_bearer - break the socket/bearer association */
747 static void cleanup_bearer(struct work_struct *work)
748 {
749 	struct udp_bearer *ub = container_of(work, struct udp_bearer, work);
750 	struct udp_replicast *rcast, *tmp;
751 
752 	list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
753 		list_del_rcu(&rcast->list);
754 		kfree_rcu(rcast, rcu);
755 	}
756 
757 	if (ub->ubsock)
758 		udp_tunnel_sock_release(ub->ubsock);
759 	synchronize_net();
760 	kfree(ub);
761 }
762 
763 /* tipc_udp_disable - detach bearer from socket */
764 static void tipc_udp_disable(struct tipc_bearer *b)
765 {
766 	struct udp_bearer *ub;
767 
768 	ub = rcu_dereference_rtnl(b->media_ptr);
769 	if (!ub) {
770 		pr_err("UDP bearer instance not found\n");
771 		return;
772 	}
773 	if (ub->ubsock)
774 		sock_set_flag(ub->ubsock->sk, SOCK_DEAD);
775 	RCU_INIT_POINTER(ub->bearer, NULL);
776 
777 	/* sock_release need to be done outside of rtnl lock */
778 	INIT_WORK(&ub->work, cleanup_bearer);
779 	schedule_work(&ub->work);
780 }
781 
782 struct tipc_media udp_media_info = {
783 	.send_msg	= tipc_udp_send_msg,
784 	.enable_media	= tipc_udp_enable,
785 	.disable_media	= tipc_udp_disable,
786 	.addr2str	= tipc_udp_addr2str,
787 	.addr2msg	= tipc_udp_addr2msg,
788 	.msg2addr	= tipc_udp_msg2addr,
789 	.priority	= TIPC_DEF_LINK_PRI,
790 	.tolerance	= TIPC_DEF_LINK_TOL,
791 	.window		= TIPC_DEF_LINK_WIN,
792 	.type_id	= TIPC_MEDIA_TYPE_UDP,
793 	.hwaddr_len	= 0,
794 	.name		= "udp"
795 };
796