xref: /linux/net/l2tp/l2tp_netlink.c (revision 5f77c18ea55601822f9c495135a5b5d4b499d647)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* L2TP netlink layer, for management
3  *
4  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
5  *
6  * Partly based on the IrDA nelink implementation
7  * (see net/irda/irnetlink.c) which is:
8  * Copyright (c) 2007 Samuel Ortiz <samuel@sortiz.org>
9  * which is in turn partly based on the wireless netlink code:
10  * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
11  */
12 
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 
15 #include <net/sock.h>
16 #include <net/genetlink.h>
17 #include <net/udp.h>
18 #include <linux/in.h>
19 #include <linux/udp.h>
20 #include <linux/socket.h>
21 #include <linux/module.h>
22 #include <linux/list.h>
23 #include <net/net_namespace.h>
24 
25 #include <linux/l2tp.h>
26 
27 #include "l2tp_core.h"
28 
29 static struct genl_family l2tp_nl_family;
30 
31 static const struct genl_multicast_group l2tp_multicast_group[] = {
32 	{
33 		.name = L2TP_GENL_MCGROUP,
34 	},
35 };
36 
37 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq,
38 			       int flags, struct l2tp_tunnel *tunnel, u8 cmd);
39 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq,
40 				int flags, struct l2tp_session *session,
41 				u8 cmd);
42 
43 /* Accessed under genl lock */
44 static const struct l2tp_nl_cmd_ops *l2tp_nl_cmd_ops[__L2TP_PWTYPE_MAX];
45 
46 static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
47 {
48 	u32 tunnel_id;
49 	u32 session_id;
50 	char *ifname;
51 	struct l2tp_tunnel *tunnel;
52 	struct l2tp_session *session = NULL;
53 	struct net *net = genl_info_net(info);
54 
55 	if (info->attrs[L2TP_ATTR_IFNAME]) {
56 		ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
57 		session = l2tp_session_get_by_ifname(net, ifname);
58 	} else if ((info->attrs[L2TP_ATTR_SESSION_ID]) &&
59 		   (info->attrs[L2TP_ATTR_CONN_ID])) {
60 		tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
61 		session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
62 		tunnel = l2tp_tunnel_get(net, tunnel_id);
63 		if (tunnel) {
64 			session = l2tp_session_get(net, tunnel->sock, tunnel->version,
65 						   tunnel_id, session_id);
66 			l2tp_tunnel_dec_refcount(tunnel);
67 		}
68 	}
69 
70 	return session;
71 }
72 
73 static int l2tp_nl_cmd_noop(struct sk_buff *skb, struct genl_info *info)
74 {
75 	struct sk_buff *msg;
76 	void *hdr;
77 	int ret = -ENOBUFS;
78 
79 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
80 	if (!msg) {
81 		ret = -ENOMEM;
82 		goto out;
83 	}
84 
85 	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
86 			  &l2tp_nl_family, 0, L2TP_CMD_NOOP);
87 	if (!hdr) {
88 		ret = -EMSGSIZE;
89 		goto err_out;
90 	}
91 
92 	genlmsg_end(msg, hdr);
93 
94 	return genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
95 
96 err_out:
97 	nlmsg_free(msg);
98 
99 out:
100 	return ret;
101 }
102 
103 static int l2tp_tunnel_notify(struct genl_family *family,
104 			      struct genl_info *info,
105 			      struct l2tp_tunnel *tunnel,
106 			      u8 cmd)
107 {
108 	struct sk_buff *msg;
109 	int ret;
110 
111 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
112 	if (!msg)
113 		return -ENOMEM;
114 
115 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
116 				  NLM_F_ACK, tunnel, cmd);
117 
118 	if (ret >= 0) {
119 		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
120 		/* We don't care if no one is listening */
121 		if (ret == -ESRCH)
122 			ret = 0;
123 		return ret;
124 	}
125 
126 	nlmsg_free(msg);
127 
128 	return ret;
129 }
130 
131 static int l2tp_session_notify(struct genl_family *family,
132 			       struct genl_info *info,
133 			       struct l2tp_session *session,
134 			       u8 cmd)
135 {
136 	struct sk_buff *msg;
137 	int ret;
138 
139 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
140 	if (!msg)
141 		return -ENOMEM;
142 
143 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
144 				   NLM_F_ACK, session, cmd);
145 
146 	if (ret >= 0) {
147 		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
148 		/* We don't care if no one is listening */
149 		if (ret == -ESRCH)
150 			ret = 0;
151 		return ret;
152 	}
153 
154 	nlmsg_free(msg);
155 
156 	return ret;
157 }
158 
159 static int l2tp_nl_cmd_tunnel_create_get_addr(struct nlattr **attrs, struct l2tp_tunnel_cfg *cfg)
160 {
161 	if (attrs[L2TP_ATTR_UDP_SPORT])
162 		cfg->local_udp_port = nla_get_u16(attrs[L2TP_ATTR_UDP_SPORT]);
163 	if (attrs[L2TP_ATTR_UDP_DPORT])
164 		cfg->peer_udp_port = nla_get_u16(attrs[L2TP_ATTR_UDP_DPORT]);
165 	cfg->use_udp_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_CSUM]);
166 
167 	/* Must have either AF_INET or AF_INET6 address for source and destination */
168 #if IS_ENABLED(CONFIG_IPV6)
169 	if (attrs[L2TP_ATTR_IP6_SADDR] && attrs[L2TP_ATTR_IP6_DADDR]) {
170 		cfg->local_ip6 = nla_data(attrs[L2TP_ATTR_IP6_SADDR]);
171 		cfg->peer_ip6 = nla_data(attrs[L2TP_ATTR_IP6_DADDR]);
172 		cfg->udp6_zero_tx_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_ZERO_CSUM6_TX]);
173 		cfg->udp6_zero_rx_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_ZERO_CSUM6_RX]);
174 		return 0;
175 	}
176 #endif
177 	if (attrs[L2TP_ATTR_IP_SADDR] && attrs[L2TP_ATTR_IP_DADDR]) {
178 		cfg->local_ip.s_addr = nla_get_in_addr(attrs[L2TP_ATTR_IP_SADDR]);
179 		cfg->peer_ip.s_addr = nla_get_in_addr(attrs[L2TP_ATTR_IP_DADDR]);
180 		return 0;
181 	}
182 	return -EINVAL;
183 }
184 
185 static int l2tp_nl_cmd_tunnel_create(struct sk_buff *skb, struct genl_info *info)
186 {
187 	u32 tunnel_id;
188 	u32 peer_tunnel_id;
189 	int proto_version;
190 	int fd = -1;
191 	int ret = 0;
192 	struct l2tp_tunnel_cfg cfg = { 0, };
193 	struct l2tp_tunnel *tunnel;
194 	struct net *net = genl_info_net(info);
195 	struct nlattr **attrs = info->attrs;
196 
197 	if (!attrs[L2TP_ATTR_CONN_ID]) {
198 		ret = -EINVAL;
199 		goto out;
200 	}
201 	tunnel_id = nla_get_u32(attrs[L2TP_ATTR_CONN_ID]);
202 
203 	if (!attrs[L2TP_ATTR_PEER_CONN_ID]) {
204 		ret = -EINVAL;
205 		goto out;
206 	}
207 	peer_tunnel_id = nla_get_u32(attrs[L2TP_ATTR_PEER_CONN_ID]);
208 
209 	if (!attrs[L2TP_ATTR_PROTO_VERSION]) {
210 		ret = -EINVAL;
211 		goto out;
212 	}
213 	proto_version = nla_get_u8(attrs[L2TP_ATTR_PROTO_VERSION]);
214 
215 	if (!attrs[L2TP_ATTR_ENCAP_TYPE]) {
216 		ret = -EINVAL;
217 		goto out;
218 	}
219 	cfg.encap = nla_get_u16(attrs[L2TP_ATTR_ENCAP_TYPE]);
220 
221 	/* Managed tunnels take the tunnel socket from userspace.
222 	 * Unmanaged tunnels must call out the source and destination addresses
223 	 * for the kernel to create the tunnel socket itself.
224 	 */
225 	if (attrs[L2TP_ATTR_FD]) {
226 		fd = nla_get_u32(attrs[L2TP_ATTR_FD]);
227 	} else {
228 		ret = l2tp_nl_cmd_tunnel_create_get_addr(attrs, &cfg);
229 		if (ret < 0)
230 			goto out;
231 	}
232 
233 	ret = -EINVAL;
234 	switch (cfg.encap) {
235 	case L2TP_ENCAPTYPE_UDP:
236 	case L2TP_ENCAPTYPE_IP:
237 		ret = l2tp_tunnel_create(fd, proto_version, tunnel_id,
238 					 peer_tunnel_id, &cfg, &tunnel);
239 		break;
240 	}
241 
242 	if (ret < 0)
243 		goto out;
244 
245 	l2tp_tunnel_inc_refcount(tunnel);
246 	ret = l2tp_tunnel_register(tunnel, net, &cfg);
247 	if (ret < 0) {
248 		kfree(tunnel);
249 		goto out;
250 	}
251 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info, tunnel,
252 				 L2TP_CMD_TUNNEL_CREATE);
253 	l2tp_tunnel_dec_refcount(tunnel);
254 
255 out:
256 	return ret;
257 }
258 
259 static int l2tp_nl_cmd_tunnel_delete(struct sk_buff *skb, struct genl_info *info)
260 {
261 	struct l2tp_tunnel *tunnel;
262 	u32 tunnel_id;
263 	int ret = 0;
264 	struct net *net = genl_info_net(info);
265 
266 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
267 		ret = -EINVAL;
268 		goto out;
269 	}
270 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
271 
272 	tunnel = l2tp_tunnel_get(net, tunnel_id);
273 	if (!tunnel) {
274 		ret = -ENODEV;
275 		goto out;
276 	}
277 
278 	l2tp_tunnel_notify(&l2tp_nl_family, info,
279 			   tunnel, L2TP_CMD_TUNNEL_DELETE);
280 
281 	l2tp_tunnel_delete(tunnel);
282 
283 	l2tp_tunnel_dec_refcount(tunnel);
284 
285 out:
286 	return ret;
287 }
288 
289 static int l2tp_nl_cmd_tunnel_modify(struct sk_buff *skb, struct genl_info *info)
290 {
291 	struct l2tp_tunnel *tunnel;
292 	u32 tunnel_id;
293 	int ret = 0;
294 	struct net *net = genl_info_net(info);
295 
296 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
297 		ret = -EINVAL;
298 		goto out;
299 	}
300 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
301 
302 	tunnel = l2tp_tunnel_get(net, tunnel_id);
303 	if (!tunnel) {
304 		ret = -ENODEV;
305 		goto out;
306 	}
307 
308 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info,
309 				 tunnel, L2TP_CMD_TUNNEL_MODIFY);
310 
311 	l2tp_tunnel_dec_refcount(tunnel);
312 
313 out:
314 	return ret;
315 }
316 
317 #if IS_ENABLED(CONFIG_IPV6)
318 static int l2tp_nl_tunnel_send_addr6(struct sk_buff *skb, struct sock *sk,
319 				     enum l2tp_encap_type encap)
320 {
321 	struct inet_sock *inet = inet_sk(sk);
322 	struct ipv6_pinfo *np = inet6_sk(sk);
323 
324 	switch (encap) {
325 	case L2TP_ENCAPTYPE_UDP:
326 		if (udp_get_no_check6_tx(sk) &&
327 		    nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_TX))
328 			return -1;
329 		if (udp_get_no_check6_rx(sk) &&
330 		    nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_RX))
331 			return -1;
332 		if (nla_put_u16(skb, L2TP_ATTR_UDP_SPORT, ntohs(inet->inet_sport)) ||
333 		    nla_put_u16(skb, L2TP_ATTR_UDP_DPORT, ntohs(inet->inet_dport)))
334 			return -1;
335 		fallthrough;
336 	case L2TP_ENCAPTYPE_IP:
337 		if (nla_put_in6_addr(skb, L2TP_ATTR_IP6_SADDR, &np->saddr) ||
338 		    nla_put_in6_addr(skb, L2TP_ATTR_IP6_DADDR, &sk->sk_v6_daddr))
339 			return -1;
340 		break;
341 	}
342 	return 0;
343 }
344 #endif
345 
346 static int l2tp_nl_tunnel_send_addr4(struct sk_buff *skb, struct sock *sk,
347 				     enum l2tp_encap_type encap)
348 {
349 	struct inet_sock *inet = inet_sk(sk);
350 
351 	switch (encap) {
352 	case L2TP_ENCAPTYPE_UDP:
353 		if (nla_put_u8(skb, L2TP_ATTR_UDP_CSUM, !sk->sk_no_check_tx) ||
354 		    nla_put_u16(skb, L2TP_ATTR_UDP_SPORT, ntohs(inet->inet_sport)) ||
355 		    nla_put_u16(skb, L2TP_ATTR_UDP_DPORT, ntohs(inet->inet_dport)))
356 			return -1;
357 		fallthrough;
358 	case L2TP_ENCAPTYPE_IP:
359 		if (nla_put_in_addr(skb, L2TP_ATTR_IP_SADDR, inet->inet_saddr) ||
360 		    nla_put_in_addr(skb, L2TP_ATTR_IP_DADDR, inet->inet_daddr))
361 			return -1;
362 		break;
363 	}
364 
365 	return 0;
366 }
367 
368 /* Append attributes for the tunnel address, handling the different attribute types
369  * used for different tunnel encapsulation and AF_INET v.s. AF_INET6.
370  */
371 static int l2tp_nl_tunnel_send_addr(struct sk_buff *skb, struct l2tp_tunnel *tunnel)
372 {
373 	struct sock *sk = tunnel->sock;
374 
375 	if (!sk)
376 		return 0;
377 
378 #if IS_ENABLED(CONFIG_IPV6)
379 	if (sk->sk_family == AF_INET6)
380 		return l2tp_nl_tunnel_send_addr6(skb, sk, tunnel->encap);
381 #endif
382 	return l2tp_nl_tunnel_send_addr4(skb, sk, tunnel->encap);
383 }
384 
385 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
386 			       struct l2tp_tunnel *tunnel, u8 cmd)
387 {
388 	void *hdr;
389 	struct nlattr *nest;
390 
391 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
392 	if (!hdr)
393 		return -EMSGSIZE;
394 
395 	if (nla_put_u8(skb, L2TP_ATTR_PROTO_VERSION, tunnel->version) ||
396 	    nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
397 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
398 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, 0) ||
399 	    nla_put_u16(skb, L2TP_ATTR_ENCAP_TYPE, tunnel->encap))
400 		goto nla_put_failure;
401 
402 	nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
403 	if (!nest)
404 		goto nla_put_failure;
405 
406 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
407 			      atomic_long_read(&tunnel->stats.tx_packets),
408 			      L2TP_ATTR_STATS_PAD) ||
409 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
410 			      atomic_long_read(&tunnel->stats.tx_bytes),
411 			      L2TP_ATTR_STATS_PAD) ||
412 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
413 			      atomic_long_read(&tunnel->stats.tx_errors),
414 			      L2TP_ATTR_STATS_PAD) ||
415 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
416 			      atomic_long_read(&tunnel->stats.rx_packets),
417 			      L2TP_ATTR_STATS_PAD) ||
418 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
419 			      atomic_long_read(&tunnel->stats.rx_bytes),
420 			      L2TP_ATTR_STATS_PAD) ||
421 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
422 			      atomic_long_read(&tunnel->stats.rx_seq_discards),
423 			      L2TP_ATTR_STATS_PAD) ||
424 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_COOKIE_DISCARDS,
425 			      atomic_long_read(&tunnel->stats.rx_cookie_discards),
426 			      L2TP_ATTR_STATS_PAD) ||
427 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
428 			      atomic_long_read(&tunnel->stats.rx_oos_packets),
429 			      L2TP_ATTR_STATS_PAD) ||
430 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
431 			      atomic_long_read(&tunnel->stats.rx_errors),
432 			      L2TP_ATTR_STATS_PAD) ||
433 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_INVALID,
434 			      atomic_long_read(&tunnel->stats.rx_invalid),
435 			      L2TP_ATTR_STATS_PAD))
436 		goto nla_put_failure;
437 	nla_nest_end(skb, nest);
438 
439 	if (l2tp_nl_tunnel_send_addr(skb, tunnel))
440 		goto nla_put_failure;
441 
442 	genlmsg_end(skb, hdr);
443 	return 0;
444 
445 nla_put_failure:
446 	genlmsg_cancel(skb, hdr);
447 	return -1;
448 }
449 
450 static int l2tp_nl_cmd_tunnel_get(struct sk_buff *skb, struct genl_info *info)
451 {
452 	struct l2tp_tunnel *tunnel;
453 	struct sk_buff *msg;
454 	u32 tunnel_id;
455 	int ret = -ENOBUFS;
456 	struct net *net = genl_info_net(info);
457 
458 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
459 		ret = -EINVAL;
460 		goto err;
461 	}
462 
463 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
464 
465 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
466 	if (!msg) {
467 		ret = -ENOMEM;
468 		goto err;
469 	}
470 
471 	tunnel = l2tp_tunnel_get(net, tunnel_id);
472 	if (!tunnel) {
473 		ret = -ENODEV;
474 		goto err_nlmsg;
475 	}
476 
477 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
478 				  NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);
479 	if (ret < 0)
480 		goto err_nlmsg_tunnel;
481 
482 	l2tp_tunnel_dec_refcount(tunnel);
483 
484 	return genlmsg_unicast(net, msg, info->snd_portid);
485 
486 err_nlmsg_tunnel:
487 	l2tp_tunnel_dec_refcount(tunnel);
488 err_nlmsg:
489 	nlmsg_free(msg);
490 err:
491 	return ret;
492 }
493 
494 static int l2tp_nl_cmd_tunnel_dump(struct sk_buff *skb, struct netlink_callback *cb)
495 {
496 	int ti = cb->args[0];
497 	struct l2tp_tunnel *tunnel;
498 	struct net *net = sock_net(skb->sk);
499 
500 	for (;;) {
501 		tunnel = l2tp_tunnel_get_nth(net, ti);
502 		if (!tunnel)
503 			goto out;
504 
505 		if (l2tp_nl_tunnel_send(skb, NETLINK_CB(cb->skb).portid,
506 					cb->nlh->nlmsg_seq, NLM_F_MULTI,
507 					tunnel, L2TP_CMD_TUNNEL_GET) < 0) {
508 			l2tp_tunnel_dec_refcount(tunnel);
509 			goto out;
510 		}
511 		l2tp_tunnel_dec_refcount(tunnel);
512 
513 		ti++;
514 	}
515 
516 out:
517 	cb->args[0] = ti;
518 
519 	return skb->len;
520 }
521 
522 static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *info)
523 {
524 	u32 tunnel_id = 0;
525 	u32 session_id;
526 	u32 peer_session_id;
527 	int ret = 0;
528 	struct l2tp_tunnel *tunnel;
529 	struct l2tp_session *session;
530 	struct l2tp_session_cfg cfg = { 0, };
531 	struct net *net = genl_info_net(info);
532 
533 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
534 		ret = -EINVAL;
535 		goto out;
536 	}
537 
538 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
539 	tunnel = l2tp_tunnel_get(net, tunnel_id);
540 	if (!tunnel) {
541 		ret = -ENODEV;
542 		goto out;
543 	}
544 
545 	if (!info->attrs[L2TP_ATTR_SESSION_ID]) {
546 		ret = -EINVAL;
547 		goto out_tunnel;
548 	}
549 	session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
550 
551 	if (!info->attrs[L2TP_ATTR_PEER_SESSION_ID]) {
552 		ret = -EINVAL;
553 		goto out_tunnel;
554 	}
555 	peer_session_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_SESSION_ID]);
556 
557 	if (!info->attrs[L2TP_ATTR_PW_TYPE]) {
558 		ret = -EINVAL;
559 		goto out_tunnel;
560 	}
561 	cfg.pw_type = nla_get_u16(info->attrs[L2TP_ATTR_PW_TYPE]);
562 	if (cfg.pw_type >= __L2TP_PWTYPE_MAX) {
563 		ret = -EINVAL;
564 		goto out_tunnel;
565 	}
566 
567 	/* L2TPv2 only accepts PPP pseudo-wires */
568 	if (tunnel->version == 2 && cfg.pw_type != L2TP_PWTYPE_PPP) {
569 		ret = -EPROTONOSUPPORT;
570 		goto out_tunnel;
571 	}
572 
573 	if (tunnel->version > 2) {
574 		if (info->attrs[L2TP_ATTR_L2SPEC_TYPE]) {
575 			cfg.l2specific_type = nla_get_u8(info->attrs[L2TP_ATTR_L2SPEC_TYPE]);
576 			if (cfg.l2specific_type != L2TP_L2SPECTYPE_DEFAULT &&
577 			    cfg.l2specific_type != L2TP_L2SPECTYPE_NONE) {
578 				ret = -EINVAL;
579 				goto out_tunnel;
580 			}
581 		} else {
582 			cfg.l2specific_type = L2TP_L2SPECTYPE_DEFAULT;
583 		}
584 
585 		if (info->attrs[L2TP_ATTR_COOKIE]) {
586 			u16 len = nla_len(info->attrs[L2TP_ATTR_COOKIE]);
587 
588 			if (len > 8) {
589 				ret = -EINVAL;
590 				goto out_tunnel;
591 			}
592 			cfg.cookie_len = len;
593 			memcpy(&cfg.cookie[0], nla_data(info->attrs[L2TP_ATTR_COOKIE]), len);
594 		}
595 		if (info->attrs[L2TP_ATTR_PEER_COOKIE]) {
596 			u16 len = nla_len(info->attrs[L2TP_ATTR_PEER_COOKIE]);
597 
598 			if (len > 8) {
599 				ret = -EINVAL;
600 				goto out_tunnel;
601 			}
602 			cfg.peer_cookie_len = len;
603 			memcpy(&cfg.peer_cookie[0], nla_data(info->attrs[L2TP_ATTR_PEER_COOKIE]), len);
604 		}
605 		if (info->attrs[L2TP_ATTR_IFNAME])
606 			cfg.ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
607 	}
608 
609 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
610 		cfg.recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
611 
612 	if (info->attrs[L2TP_ATTR_SEND_SEQ])
613 		cfg.send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
614 
615 	if (info->attrs[L2TP_ATTR_LNS_MODE])
616 		cfg.lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
617 
618 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
619 		cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
620 
621 #ifdef CONFIG_MODULES
622 	if (!l2tp_nl_cmd_ops[cfg.pw_type]) {
623 		genl_unlock();
624 		request_module("net-l2tp-type-%u", cfg.pw_type);
625 		genl_lock();
626 	}
627 #endif
628 	if (!l2tp_nl_cmd_ops[cfg.pw_type] || !l2tp_nl_cmd_ops[cfg.pw_type]->session_create) {
629 		ret = -EPROTONOSUPPORT;
630 		goto out_tunnel;
631 	}
632 
633 	ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
634 							   session_id,
635 							   peer_session_id,
636 							   &cfg);
637 
638 	if (ret >= 0) {
639 		session = l2tp_session_get(net, tunnel->sock, tunnel->version,
640 					   tunnel_id, session_id);
641 		if (session) {
642 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
643 						  L2TP_CMD_SESSION_CREATE);
644 			l2tp_session_dec_refcount(session);
645 		}
646 	}
647 
648 out_tunnel:
649 	l2tp_tunnel_dec_refcount(tunnel);
650 out:
651 	return ret;
652 }
653 
654 static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *info)
655 {
656 	int ret = 0;
657 	struct l2tp_session *session;
658 	u16 pw_type;
659 
660 	session = l2tp_nl_session_get(info);
661 	if (!session) {
662 		ret = -ENODEV;
663 		goto out;
664 	}
665 
666 	l2tp_session_notify(&l2tp_nl_family, info,
667 			    session, L2TP_CMD_SESSION_DELETE);
668 
669 	pw_type = session->pwtype;
670 	if (pw_type < __L2TP_PWTYPE_MAX)
671 		if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
672 			l2tp_nl_cmd_ops[pw_type]->session_delete(session);
673 
674 	l2tp_session_dec_refcount(session);
675 
676 out:
677 	return ret;
678 }
679 
680 static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *info)
681 {
682 	int ret = 0;
683 	struct l2tp_session *session;
684 
685 	session = l2tp_nl_session_get(info);
686 	if (!session) {
687 		ret = -ENODEV;
688 		goto out;
689 	}
690 
691 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
692 		session->recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
693 
694 	if (info->attrs[L2TP_ATTR_SEND_SEQ]) {
695 		session->send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
696 		l2tp_session_set_header_len(session, session->tunnel->version);
697 	}
698 
699 	if (info->attrs[L2TP_ATTR_LNS_MODE])
700 		session->lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
701 
702 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
703 		session->reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
704 
705 	ret = l2tp_session_notify(&l2tp_nl_family, info,
706 				  session, L2TP_CMD_SESSION_MODIFY);
707 
708 	l2tp_session_dec_refcount(session);
709 
710 out:
711 	return ret;
712 }
713 
714 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
715 				struct l2tp_session *session, u8 cmd)
716 {
717 	void *hdr;
718 	struct nlattr *nest;
719 	struct l2tp_tunnel *tunnel = session->tunnel;
720 
721 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
722 	if (!hdr)
723 		return -EMSGSIZE;
724 
725 	if (nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
726 	    nla_put_u32(skb, L2TP_ATTR_SESSION_ID, session->session_id) ||
727 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
728 	    nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID, session->peer_session_id) ||
729 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, 0) ||
730 	    nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype))
731 		goto nla_put_failure;
732 
733 	if ((session->ifname[0] &&
734 	     nla_put_string(skb, L2TP_ATTR_IFNAME, session->ifname)) ||
735 	    (session->cookie_len &&
736 	     nla_put(skb, L2TP_ATTR_COOKIE, session->cookie_len, session->cookie)) ||
737 	    (session->peer_cookie_len &&
738 	     nla_put(skb, L2TP_ATTR_PEER_COOKIE, session->peer_cookie_len, session->peer_cookie)) ||
739 	    nla_put_u8(skb, L2TP_ATTR_RECV_SEQ, session->recv_seq) ||
740 	    nla_put_u8(skb, L2TP_ATTR_SEND_SEQ, session->send_seq) ||
741 	    nla_put_u8(skb, L2TP_ATTR_LNS_MODE, session->lns_mode) ||
742 	    (l2tp_tunnel_uses_xfrm(tunnel) &&
743 	     nla_put_u8(skb, L2TP_ATTR_USING_IPSEC, 1)) ||
744 	    (session->reorder_timeout &&
745 	     nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT,
746 			   session->reorder_timeout, L2TP_ATTR_PAD)))
747 		goto nla_put_failure;
748 
749 	nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
750 	if (!nest)
751 		goto nla_put_failure;
752 
753 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
754 			      atomic_long_read(&session->stats.tx_packets),
755 			      L2TP_ATTR_STATS_PAD) ||
756 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
757 			      atomic_long_read(&session->stats.tx_bytes),
758 			      L2TP_ATTR_STATS_PAD) ||
759 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
760 			      atomic_long_read(&session->stats.tx_errors),
761 			      L2TP_ATTR_STATS_PAD) ||
762 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
763 			      atomic_long_read(&session->stats.rx_packets),
764 			      L2TP_ATTR_STATS_PAD) ||
765 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
766 			      atomic_long_read(&session->stats.rx_bytes),
767 			      L2TP_ATTR_STATS_PAD) ||
768 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
769 			      atomic_long_read(&session->stats.rx_seq_discards),
770 			      L2TP_ATTR_STATS_PAD) ||
771 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_COOKIE_DISCARDS,
772 			      atomic_long_read(&session->stats.rx_cookie_discards),
773 			      L2TP_ATTR_STATS_PAD) ||
774 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
775 			      atomic_long_read(&session->stats.rx_oos_packets),
776 			      L2TP_ATTR_STATS_PAD) ||
777 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
778 			      atomic_long_read(&session->stats.rx_errors),
779 			      L2TP_ATTR_STATS_PAD) ||
780 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_INVALID,
781 			      atomic_long_read(&session->stats.rx_invalid),
782 			      L2TP_ATTR_STATS_PAD))
783 		goto nla_put_failure;
784 	nla_nest_end(skb, nest);
785 
786 	genlmsg_end(skb, hdr);
787 	return 0;
788 
789  nla_put_failure:
790 	genlmsg_cancel(skb, hdr);
791 	return -1;
792 }
793 
794 static int l2tp_nl_cmd_session_get(struct sk_buff *skb, struct genl_info *info)
795 {
796 	struct l2tp_session *session;
797 	struct sk_buff *msg;
798 	int ret;
799 
800 	session = l2tp_nl_session_get(info);
801 	if (!session) {
802 		ret = -ENODEV;
803 		goto err;
804 	}
805 
806 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
807 	if (!msg) {
808 		ret = -ENOMEM;
809 		goto err_ref;
810 	}
811 
812 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
813 				   0, session, L2TP_CMD_SESSION_GET);
814 	if (ret < 0)
815 		goto err_ref_msg;
816 
817 	ret = genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
818 
819 	l2tp_session_dec_refcount(session);
820 
821 	return ret;
822 
823 err_ref_msg:
824 	nlmsg_free(msg);
825 err_ref:
826 	l2tp_session_dec_refcount(session);
827 err:
828 	return ret;
829 }
830 
831 static int l2tp_nl_cmd_session_dump(struct sk_buff *skb, struct netlink_callback *cb)
832 {
833 	struct net *net = sock_net(skb->sk);
834 	struct l2tp_session *session;
835 	struct l2tp_tunnel *tunnel = NULL;
836 	int ti = cb->args[0];
837 	int si = cb->args[1];
838 
839 	for (;;) {
840 		if (!tunnel) {
841 			tunnel = l2tp_tunnel_get_nth(net, ti);
842 			if (!tunnel)
843 				goto out;
844 		}
845 
846 		session = l2tp_session_get_nth(tunnel, si);
847 		if (!session) {
848 			ti++;
849 			l2tp_tunnel_dec_refcount(tunnel);
850 			tunnel = NULL;
851 			si = 0;
852 			continue;
853 		}
854 
855 		if (l2tp_nl_session_send(skb, NETLINK_CB(cb->skb).portid,
856 					 cb->nlh->nlmsg_seq, NLM_F_MULTI,
857 					 session, L2TP_CMD_SESSION_GET) < 0) {
858 			l2tp_session_dec_refcount(session);
859 			l2tp_tunnel_dec_refcount(tunnel);
860 			break;
861 		}
862 		l2tp_session_dec_refcount(session);
863 
864 		si++;
865 	}
866 
867 out:
868 	cb->args[0] = ti;
869 	cb->args[1] = si;
870 
871 	return skb->len;
872 }
873 
874 static const struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
875 	[L2TP_ATTR_NONE]		= { .type = NLA_UNSPEC, },
876 	[L2TP_ATTR_PW_TYPE]		= { .type = NLA_U16, },
877 	[L2TP_ATTR_ENCAP_TYPE]		= { .type = NLA_U16, },
878 	[L2TP_ATTR_OFFSET]		= { .type = NLA_U16, },
879 	[L2TP_ATTR_DATA_SEQ]		= { .type = NLA_U8, },
880 	[L2TP_ATTR_L2SPEC_TYPE]		= { .type = NLA_U8, },
881 	[L2TP_ATTR_L2SPEC_LEN]		= { .type = NLA_U8, },
882 	[L2TP_ATTR_PROTO_VERSION]	= { .type = NLA_U8, },
883 	[L2TP_ATTR_CONN_ID]		= { .type = NLA_U32, },
884 	[L2TP_ATTR_PEER_CONN_ID]	= { .type = NLA_U32, },
885 	[L2TP_ATTR_SESSION_ID]		= { .type = NLA_U32, },
886 	[L2TP_ATTR_PEER_SESSION_ID]	= { .type = NLA_U32, },
887 	[L2TP_ATTR_UDP_CSUM]		= { .type = NLA_U8, },
888 	[L2TP_ATTR_VLAN_ID]		= { .type = NLA_U16, },
889 	[L2TP_ATTR_DEBUG]		= { .type = NLA_U32, },
890 	[L2TP_ATTR_RECV_SEQ]		= { .type = NLA_U8, },
891 	[L2TP_ATTR_SEND_SEQ]		= { .type = NLA_U8, },
892 	[L2TP_ATTR_LNS_MODE]		= { .type = NLA_U8, },
893 	[L2TP_ATTR_USING_IPSEC]		= { .type = NLA_U8, },
894 	[L2TP_ATTR_RECV_TIMEOUT]	= { .type = NLA_MSECS, },
895 	[L2TP_ATTR_FD]			= { .type = NLA_U32, },
896 	[L2TP_ATTR_IP_SADDR]		= { .type = NLA_U32, },
897 	[L2TP_ATTR_IP_DADDR]		= { .type = NLA_U32, },
898 	[L2TP_ATTR_UDP_SPORT]		= { .type = NLA_U16, },
899 	[L2TP_ATTR_UDP_DPORT]		= { .type = NLA_U16, },
900 	[L2TP_ATTR_MTU]			= { .type = NLA_U16, },
901 	[L2TP_ATTR_MRU]			= { .type = NLA_U16, },
902 	[L2TP_ATTR_STATS]		= { .type = NLA_NESTED, },
903 	[L2TP_ATTR_IP6_SADDR] = {
904 		.type = NLA_BINARY,
905 		.len = sizeof(struct in6_addr),
906 	},
907 	[L2TP_ATTR_IP6_DADDR] = {
908 		.type = NLA_BINARY,
909 		.len = sizeof(struct in6_addr),
910 	},
911 	[L2TP_ATTR_IFNAME] = {
912 		.type = NLA_NUL_STRING,
913 		.len = IFNAMSIZ - 1,
914 	},
915 	[L2TP_ATTR_COOKIE] = {
916 		.type = NLA_BINARY,
917 		.len = 8,
918 	},
919 	[L2TP_ATTR_PEER_COOKIE] = {
920 		.type = NLA_BINARY,
921 		.len = 8,
922 	},
923 };
924 
925 static const struct genl_small_ops l2tp_nl_ops[] = {
926 	{
927 		.cmd = L2TP_CMD_NOOP,
928 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
929 		.doit = l2tp_nl_cmd_noop,
930 		/* can be retrieved by unprivileged users */
931 	},
932 	{
933 		.cmd = L2TP_CMD_TUNNEL_CREATE,
934 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
935 		.doit = l2tp_nl_cmd_tunnel_create,
936 		.flags = GENL_UNS_ADMIN_PERM,
937 	},
938 	{
939 		.cmd = L2TP_CMD_TUNNEL_DELETE,
940 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
941 		.doit = l2tp_nl_cmd_tunnel_delete,
942 		.flags = GENL_UNS_ADMIN_PERM,
943 	},
944 	{
945 		.cmd = L2TP_CMD_TUNNEL_MODIFY,
946 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
947 		.doit = l2tp_nl_cmd_tunnel_modify,
948 		.flags = GENL_UNS_ADMIN_PERM,
949 	},
950 	{
951 		.cmd = L2TP_CMD_TUNNEL_GET,
952 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
953 		.doit = l2tp_nl_cmd_tunnel_get,
954 		.dumpit = l2tp_nl_cmd_tunnel_dump,
955 		.flags = GENL_UNS_ADMIN_PERM,
956 	},
957 	{
958 		.cmd = L2TP_CMD_SESSION_CREATE,
959 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
960 		.doit = l2tp_nl_cmd_session_create,
961 		.flags = GENL_UNS_ADMIN_PERM,
962 	},
963 	{
964 		.cmd = L2TP_CMD_SESSION_DELETE,
965 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
966 		.doit = l2tp_nl_cmd_session_delete,
967 		.flags = GENL_UNS_ADMIN_PERM,
968 	},
969 	{
970 		.cmd = L2TP_CMD_SESSION_MODIFY,
971 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
972 		.doit = l2tp_nl_cmd_session_modify,
973 		.flags = GENL_UNS_ADMIN_PERM,
974 	},
975 	{
976 		.cmd = L2TP_CMD_SESSION_GET,
977 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
978 		.doit = l2tp_nl_cmd_session_get,
979 		.dumpit = l2tp_nl_cmd_session_dump,
980 		.flags = GENL_UNS_ADMIN_PERM,
981 	},
982 };
983 
984 static struct genl_family l2tp_nl_family __ro_after_init = {
985 	.name		= L2TP_GENL_NAME,
986 	.version	= L2TP_GENL_VERSION,
987 	.hdrsize	= 0,
988 	.maxattr	= L2TP_ATTR_MAX,
989 	.policy = l2tp_nl_policy,
990 	.netnsok	= true,
991 	.module		= THIS_MODULE,
992 	.small_ops	= l2tp_nl_ops,
993 	.n_small_ops	= ARRAY_SIZE(l2tp_nl_ops),
994 	.resv_start_op	= L2TP_CMD_SESSION_GET + 1,
995 	.mcgrps		= l2tp_multicast_group,
996 	.n_mcgrps	= ARRAY_SIZE(l2tp_multicast_group),
997 };
998 
999 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops)
1000 {
1001 	int ret;
1002 
1003 	ret = -EINVAL;
1004 	if (pw_type >= __L2TP_PWTYPE_MAX)
1005 		goto err;
1006 
1007 	genl_lock();
1008 	ret = -EBUSY;
1009 	if (l2tp_nl_cmd_ops[pw_type])
1010 		goto out;
1011 
1012 	l2tp_nl_cmd_ops[pw_type] = ops;
1013 	ret = 0;
1014 
1015 out:
1016 	genl_unlock();
1017 err:
1018 	return ret;
1019 }
1020 EXPORT_SYMBOL_GPL(l2tp_nl_register_ops);
1021 
1022 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type)
1023 {
1024 	if (pw_type < __L2TP_PWTYPE_MAX) {
1025 		genl_lock();
1026 		l2tp_nl_cmd_ops[pw_type] = NULL;
1027 		genl_unlock();
1028 	}
1029 }
1030 EXPORT_SYMBOL_GPL(l2tp_nl_unregister_ops);
1031 
1032 static int __init l2tp_nl_init(void)
1033 {
1034 	pr_info("L2TP netlink interface\n");
1035 	return genl_register_family(&l2tp_nl_family);
1036 }
1037 
1038 static void l2tp_nl_cleanup(void)
1039 {
1040 	genl_unregister_family(&l2tp_nl_family);
1041 }
1042 
1043 module_init(l2tp_nl_init);
1044 module_exit(l2tp_nl_cleanup);
1045 
1046 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1047 MODULE_DESCRIPTION("L2TP netlink");
1048 MODULE_LICENSE("GPL");
1049 MODULE_VERSION("1.0");
1050 MODULE_ALIAS_GENL_FAMILY("l2tp");
1051