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 "msg.h"
52
53/* IANA assigned UDP port */
54#define UDP_PORT_DEFAULT	6118
55
56static const struct nla_policy tipc_nl_udp_policy[TIPC_NLA_UDP_MAX + 1] = {
57	[TIPC_NLA_UDP_UNSPEC]	= {.type = NLA_UNSPEC},
58	[TIPC_NLA_UDP_LOCAL]	= {.type = NLA_BINARY,
59				   .len = sizeof(struct sockaddr_storage)},
60	[TIPC_NLA_UDP_REMOTE]	= {.type = NLA_BINARY,
61				   .len = sizeof(struct sockaddr_storage)},
62};
63
64/**
65 * struct udp_media_addr - IP/UDP addressing information
66 *
67 * This is the bearer level originating address used in neighbor discovery
68 * messages, and all fields should be in network byte order
69 */
70struct udp_media_addr {
71	__be16	proto;
72	__be16	udp_port;
73	union {
74		struct in_addr ipv4;
75		struct in6_addr ipv6;
76	};
77};
78
79/**
80 * struct udp_bearer - ip/udp bearer data structure
81 * @bearer:	associated generic tipc bearer
82 * @ubsock:	bearer associated socket
83 * @ifindex:	local address scope
84 * @work:	used to schedule deferred work on a bearer
85 */
86struct udp_bearer {
87	struct tipc_bearer __rcu *bearer;
88	struct socket *ubsock;
89	u32 ifindex;
90	struct work_struct work;
91};
92
93/* udp_media_addr_set - convert a ip/udp address to a TIPC media address */
94static void tipc_udp_media_addr_set(struct tipc_media_addr *addr,
95				    struct udp_media_addr *ua)
96{
97	memset(addr, 0, sizeof(struct tipc_media_addr));
98	addr->media_id = TIPC_MEDIA_TYPE_UDP;
99	memcpy(addr->value, ua, sizeof(struct udp_media_addr));
100	if (ntohs(ua->proto) == ETH_P_IP) {
101		if (ipv4_is_multicast(ua->ipv4.s_addr))
102			addr->broadcast = 1;
103	} else if (ntohs(ua->proto) == ETH_P_IPV6) {
104		if (ipv6_addr_type(&ua->ipv6) & IPV6_ADDR_MULTICAST)
105			addr->broadcast = 1;
106	} else {
107		pr_err("Invalid UDP media address\n");
108	}
109}
110
111/* tipc_udp_addr2str - convert ip/udp address to string */
112static int tipc_udp_addr2str(struct tipc_media_addr *a, char *buf, int size)
113{
114	struct udp_media_addr *ua = (struct udp_media_addr *)&a->value;
115
116	if (ntohs(ua->proto) == ETH_P_IP)
117		snprintf(buf, size, "%pI4:%u", &ua->ipv4, ntohs(ua->udp_port));
118	else if (ntohs(ua->proto) == ETH_P_IPV6)
119		snprintf(buf, size, "%pI6:%u", &ua->ipv6, ntohs(ua->udp_port));
120	else
121		pr_err("Invalid UDP media address\n");
122	return 0;
123}
124
125/* tipc_udp_msg2addr - extract an ip/udp address from a TIPC ndisc message */
126static int tipc_udp_msg2addr(struct tipc_bearer *b, struct tipc_media_addr *a,
127			     char *msg)
128{
129	struct udp_media_addr *ua;
130
131	ua = (struct udp_media_addr *) (msg + TIPC_MEDIA_ADDR_OFFSET);
132	if (msg[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_UDP)
133		return -EINVAL;
134	tipc_udp_media_addr_set(a, ua);
135	return 0;
136}
137
138/* tipc_udp_addr2msg - write an ip/udp address to a TIPC ndisc message */
139static int tipc_udp_addr2msg(char *msg, struct tipc_media_addr *a)
140{
141	memset(msg, 0, TIPC_MEDIA_INFO_SIZE);
142	msg[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_UDP;
143	memcpy(msg + TIPC_MEDIA_ADDR_OFFSET, a->value,
144	       sizeof(struct udp_media_addr));
145	return 0;
146}
147
148/* tipc_send_msg - enqueue a send request */
149static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
150			     struct tipc_bearer *b,
151			     struct tipc_media_addr *dest)
152{
153	int ttl, err = 0;
154	struct udp_bearer *ub;
155	struct udp_media_addr *dst = (struct udp_media_addr *)&dest->value;
156	struct udp_media_addr *src = (struct udp_media_addr *)&b->addr.value;
157	struct sk_buff *clone;
158	struct rtable *rt;
159
160	clone = skb_clone(skb, GFP_ATOMIC);
161	skb_set_inner_protocol(clone, htons(ETH_P_TIPC));
162	ub = rcu_dereference_rtnl(b->media_ptr);
163	if (!ub) {
164		err = -ENODEV;
165		goto tx_error;
166	}
167	if (dst->proto == htons(ETH_P_IP)) {
168		struct flowi4 fl = {
169			.daddr = dst->ipv4.s_addr,
170			.saddr = src->ipv4.s_addr,
171			.flowi4_mark = clone->mark,
172			.flowi4_proto = IPPROTO_UDP
173		};
174		rt = ip_route_output_key(net, &fl);
175		if (IS_ERR(rt)) {
176			err = PTR_ERR(rt);
177			goto tx_error;
178		}
179		ttl = ip4_dst_hoplimit(&rt->dst);
180		err = udp_tunnel_xmit_skb(rt, ub->ubsock->sk, clone,
181					  src->ipv4.s_addr,
182					  dst->ipv4.s_addr, 0, ttl, 0,
183					  src->udp_port, dst->udp_port,
184					  false, true);
185		if (err < 0) {
186			ip_rt_put(rt);
187			goto tx_error;
188		}
189#if IS_ENABLED(CONFIG_IPV6)
190	} else {
191		struct dst_entry *ndst;
192		struct flowi6 fl6 = {
193			.flowi6_oif = ub->ifindex,
194			.daddr = dst->ipv6,
195			.saddr = src->ipv6,
196			.flowi6_proto = IPPROTO_UDP
197		};
198		err = ipv6_stub->ipv6_dst_lookup(ub->ubsock->sk, &ndst, &fl6);
199		if (err)
200			goto tx_error;
201		ttl = ip6_dst_hoplimit(ndst);
202		err = udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, clone,
203					   ndst->dev, &src->ipv6,
204					   &dst->ipv6, 0, ttl, src->udp_port,
205					   dst->udp_port, false);
206#endif
207	}
208	return err;
209
210tx_error:
211	kfree_skb(clone);
212	return err;
213}
214
215/* tipc_udp_recv - read data from bearer socket */
216static int tipc_udp_recv(struct sock *sk, struct sk_buff *skb)
217{
218	struct udp_bearer *ub;
219	struct tipc_bearer *b;
220	int usr = msg_user(buf_msg(skb));
221
222	if ((usr == LINK_PROTOCOL) || (usr == NAME_DISTRIBUTOR))
223		skb_linearize(skb);
224
225	ub = rcu_dereference_sk_user_data(sk);
226	if (!ub) {
227		pr_err_ratelimited("Failed to get UDP bearer reference");
228		kfree_skb(skb);
229		return 0;
230	}
231
232	skb_pull(skb, sizeof(struct udphdr));
233	rcu_read_lock();
234	b = rcu_dereference_rtnl(ub->bearer);
235
236	if (b) {
237		tipc_rcv(sock_net(sk), skb, b);
238		rcu_read_unlock();
239		return 0;
240	}
241	rcu_read_unlock();
242	kfree_skb(skb);
243	return 0;
244}
245
246static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
247{
248	int err = 0;
249	struct ip_mreqn mreqn;
250	struct sock *sk = ub->ubsock->sk;
251
252	if (ntohs(remote->proto) == ETH_P_IP) {
253		if (!ipv4_is_multicast(remote->ipv4.s_addr))
254			return 0;
255		mreqn.imr_multiaddr = remote->ipv4;
256		mreqn.imr_ifindex = ub->ifindex;
257		err = ip_mc_join_group(sk, &mreqn);
258#if IS_ENABLED(CONFIG_IPV6)
259	} else {
260		if (!ipv6_addr_is_multicast(&remote->ipv6))
261			return 0;
262		err = ipv6_stub->ipv6_sock_mc_join(sk, ub->ifindex,
263						   &remote->ipv6);
264#endif
265	}
266	return err;
267}
268
269/**
270 * parse_options - build local/remote addresses from configuration
271 * @attrs:	netlink config data
272 * @ub:		UDP bearer instance
273 * @local:	local bearer IP address/port
274 * @remote:	peer or multicast IP/port
275 */
276static int parse_options(struct nlattr *attrs[], struct udp_bearer *ub,
277			 struct udp_media_addr *local,
278			 struct udp_media_addr *remote)
279{
280	struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
281	struct sockaddr_storage *sa_local, *sa_remote;
282
283	if (!attrs[TIPC_NLA_BEARER_UDP_OPTS])
284		goto err;
285	if (nla_parse_nested(opts, TIPC_NLA_UDP_MAX,
286			     attrs[TIPC_NLA_BEARER_UDP_OPTS],
287			     tipc_nl_udp_policy))
288		goto err;
289	if (opts[TIPC_NLA_UDP_LOCAL] && opts[TIPC_NLA_UDP_REMOTE]) {
290		sa_local = nla_data(opts[TIPC_NLA_UDP_LOCAL]);
291		sa_remote = nla_data(opts[TIPC_NLA_UDP_REMOTE]);
292	} else {
293err:
294		pr_err("Invalid UDP bearer configuration");
295		return -EINVAL;
296	}
297	if ((sa_local->ss_family & sa_remote->ss_family) == AF_INET) {
298		struct sockaddr_in *ip4;
299
300		ip4 = (struct sockaddr_in *)sa_local;
301		local->proto = htons(ETH_P_IP);
302		local->udp_port = ip4->sin_port;
303		local->ipv4.s_addr = ip4->sin_addr.s_addr;
304
305		ip4 = (struct sockaddr_in *)sa_remote;
306		remote->proto = htons(ETH_P_IP);
307		remote->udp_port = ip4->sin_port;
308		remote->ipv4.s_addr = ip4->sin_addr.s_addr;
309		return 0;
310
311#if IS_ENABLED(CONFIG_IPV6)
312	} else if ((sa_local->ss_family & sa_remote->ss_family) == AF_INET6) {
313		struct sockaddr_in6 *ip6;
314
315		ip6 = (struct sockaddr_in6 *)sa_local;
316		local->proto = htons(ETH_P_IPV6);
317		local->udp_port = ip6->sin6_port;
318		local->ipv6 = ip6->sin6_addr;
319		ub->ifindex = ip6->sin6_scope_id;
320
321		ip6 = (struct sockaddr_in6 *)sa_remote;
322		remote->proto = htons(ETH_P_IPV6);
323		remote->udp_port = ip6->sin6_port;
324		remote->ipv6 = ip6->sin6_addr;
325		return 0;
326#endif
327	}
328	return -EADDRNOTAVAIL;
329}
330
331/**
332 * tipc_udp_enable - callback to create a new udp bearer instance
333 * @net:	network namespace
334 * @b:		pointer to generic tipc_bearer
335 * @attrs:	netlink bearer configuration
336 *
337 * validate the bearer parameters and initialize the udp bearer
338 * rtnl_lock should be held
339 */
340static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
341			   struct nlattr *attrs[])
342{
343	int err = -EINVAL;
344	struct udp_bearer *ub;
345	struct udp_media_addr *remote;
346	struct udp_media_addr local = {0};
347	struct udp_port_cfg udp_conf = {0};
348	struct udp_tunnel_sock_cfg tuncfg = {NULL};
349
350	ub = kzalloc(sizeof(*ub), GFP_ATOMIC);
351	if (!ub)
352		return -ENOMEM;
353
354	remote = (struct udp_media_addr *)&b->bcast_addr.value;
355	memset(remote, 0, sizeof(struct udp_media_addr));
356	err = parse_options(attrs, ub, &local, remote);
357	if (err)
358		goto err;
359
360	b->bcast_addr.media_id = TIPC_MEDIA_TYPE_UDP;
361	b->bcast_addr.broadcast = 1;
362	rcu_assign_pointer(b->media_ptr, ub);
363	rcu_assign_pointer(ub->bearer, b);
364	tipc_udp_media_addr_set(&b->addr, &local);
365	if (local.proto == htons(ETH_P_IP)) {
366		struct net_device *dev;
367
368		dev = __ip_dev_find(net, local.ipv4.s_addr, false);
369		if (!dev) {
370			err = -ENODEV;
371			goto err;
372		}
373		udp_conf.family = AF_INET;
374		udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
375		udp_conf.use_udp_checksums = false;
376		ub->ifindex = dev->ifindex;
377		b->mtu = dev->mtu - sizeof(struct iphdr)
378			- sizeof(struct udphdr);
379#if IS_ENABLED(CONFIG_IPV6)
380	} else if (local.proto == htons(ETH_P_IPV6)) {
381		udp_conf.family = AF_INET6;
382		udp_conf.use_udp6_tx_checksums = true;
383		udp_conf.use_udp6_rx_checksums = true;
384		udp_conf.local_ip6 = in6addr_any;
385		b->mtu = 1280;
386#endif
387	} else {
388		err = -EAFNOSUPPORT;
389		goto err;
390	}
391	udp_conf.local_udp_port = local.udp_port;
392	err = udp_sock_create(net, &udp_conf, &ub->ubsock);
393	if (err)
394		goto err;
395	tuncfg.sk_user_data = ub;
396	tuncfg.encap_type = 1;
397	tuncfg.encap_rcv = tipc_udp_recv;
398	tuncfg.encap_destroy = NULL;
399	setup_udp_tunnel_sock(net, ub->ubsock, &tuncfg);
400
401	if (enable_mcast(ub, remote))
402		goto err;
403	return 0;
404err:
405	kfree(ub);
406	return err;
407}
408
409/* cleanup_bearer - break the socket/bearer association */
410static void cleanup_bearer(struct work_struct *work)
411{
412	struct udp_bearer *ub = container_of(work, struct udp_bearer, work);
413
414	if (ub->ubsock)
415		udp_tunnel_sock_release(ub->ubsock);
416	synchronize_net();
417	kfree(ub);
418}
419
420/* tipc_udp_disable - detach bearer from socket */
421static void tipc_udp_disable(struct tipc_bearer *b)
422{
423	struct udp_bearer *ub;
424
425	ub = rcu_dereference_rtnl(b->media_ptr);
426	if (!ub) {
427		pr_err("UDP bearer instance not found\n");
428		return;
429	}
430	if (ub->ubsock)
431		sock_set_flag(ub->ubsock->sk, SOCK_DEAD);
432	RCU_INIT_POINTER(b->media_ptr, NULL);
433	RCU_INIT_POINTER(ub->bearer, NULL);
434
435	/* sock_release need to be done outside of rtnl lock */
436	INIT_WORK(&ub->work, cleanup_bearer);
437	schedule_work(&ub->work);
438}
439
440struct tipc_media udp_media_info = {
441	.send_msg	= tipc_udp_send_msg,
442	.enable_media	= tipc_udp_enable,
443	.disable_media	= tipc_udp_disable,
444	.addr2str	= tipc_udp_addr2str,
445	.addr2msg	= tipc_udp_addr2msg,
446	.msg2addr	= tipc_udp_msg2addr,
447	.priority	= TIPC_DEF_LINK_PRI,
448	.tolerance	= TIPC_DEF_LINK_TOL,
449	.window		= TIPC_DEF_LINK_WIN,
450	.type_id	= TIPC_MEDIA_TYPE_UDP,
451	.hwaddr_len	= 0,
452	.name		= "udp"
453};
454