xref: /openbmc/linux/net/l2tp/l2tp_netlink.c (revision 3ac14b39) 
1 /*
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  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License version 2 as
14  * published by the Free Software Foundation.
15  */
16 
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 
19 #include <net/sock.h>
20 #include <net/genetlink.h>
21 #include <net/udp.h>
22 #include <linux/in.h>
23 #include <linux/udp.h>
24 #include <linux/socket.h>
25 #include <linux/module.h>
26 #include <linux/list.h>
27 #include <net/net_namespace.h>
28 
29 #include <linux/l2tp.h>
30 
31 #include "l2tp_core.h"
32 
33 
34 static struct genl_family l2tp_nl_family;
35 
36 static const struct genl_multicast_group l2tp_multicast_group[] = {
37 	{
38 		.name = L2TP_GENL_MCGROUP,
39 	},
40 };
41 
42 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq,
43 			       int flags, struct l2tp_tunnel *tunnel, u8 cmd);
44 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq,
45 				int flags, struct l2tp_session *session,
46 				u8 cmd);
47 
48 /* Accessed under genl lock */
49 static const struct l2tp_nl_cmd_ops *l2tp_nl_cmd_ops[__L2TP_PWTYPE_MAX];
50 
51 static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
52 {
53 	u32 tunnel_id;
54 	u32 session_id;
55 	char *ifname;
56 	struct l2tp_tunnel *tunnel;
57 	struct l2tp_session *session = NULL;
58 	struct net *net = genl_info_net(info);
59 
60 	if (info->attrs[L2TP_ATTR_IFNAME]) {
61 		ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
62 		session = l2tp_session_get_by_ifname(net, ifname);
63 	} else if ((info->attrs[L2TP_ATTR_SESSION_ID]) &&
64 		   (info->attrs[L2TP_ATTR_CONN_ID])) {
65 		tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
66 		session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
67 		tunnel = l2tp_tunnel_get(net, tunnel_id);
68 		if (tunnel) {
69 			session = l2tp_session_get(net, tunnel, session_id);
70 			l2tp_tunnel_dec_refcount(tunnel);
71 		}
72 	}
73 
74 	return session;
75 }
76 
77 static int l2tp_nl_cmd_noop(struct sk_buff *skb, struct genl_info *info)
78 {
79 	struct sk_buff *msg;
80 	void *hdr;
81 	int ret = -ENOBUFS;
82 
83 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
84 	if (!msg) {
85 		ret = -ENOMEM;
86 		goto out;
87 	}
88 
89 	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
90 			  &l2tp_nl_family, 0, L2TP_CMD_NOOP);
91 	if (!hdr) {
92 		ret = -EMSGSIZE;
93 		goto err_out;
94 	}
95 
96 	genlmsg_end(msg, hdr);
97 
98 	return genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
99 
100 err_out:
101 	nlmsg_free(msg);
102 
103 out:
104 	return ret;
105 }
106 
107 static int l2tp_tunnel_notify(struct genl_family *family,
108 			      struct genl_info *info,
109 			      struct l2tp_tunnel *tunnel,
110 			      u8 cmd)
111 {
112 	struct sk_buff *msg;
113 	int ret;
114 
115 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
116 	if (!msg)
117 		return -ENOMEM;
118 
119 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
120 				  NLM_F_ACK, tunnel, cmd);
121 
122 	if (ret >= 0) {
123 		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
124 		/* We don't care if no one is listening */
125 		if (ret == -ESRCH)
126 			ret = 0;
127 		return ret;
128 	}
129 
130 	nlmsg_free(msg);
131 
132 	return ret;
133 }
134 
135 static int l2tp_session_notify(struct genl_family *family,
136 			       struct genl_info *info,
137 			       struct l2tp_session *session,
138 			       u8 cmd)
139 {
140 	struct sk_buff *msg;
141 	int ret;
142 
143 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
144 	if (!msg)
145 		return -ENOMEM;
146 
147 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
148 				   NLM_F_ACK, session, cmd);
149 
150 	if (ret >= 0) {
151 		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
152 		/* We don't care if no one is listening */
153 		if (ret == -ESRCH)
154 			ret = 0;
155 		return ret;
156 	}
157 
158 	nlmsg_free(msg);
159 
160 	return ret;
161 }
162 
163 static int l2tp_nl_cmd_tunnel_create(struct sk_buff *skb, struct genl_info *info)
164 {
165 	u32 tunnel_id;
166 	u32 peer_tunnel_id;
167 	int proto_version;
168 	int fd;
169 	int ret = 0;
170 	struct l2tp_tunnel_cfg cfg = { 0, };
171 	struct l2tp_tunnel *tunnel;
172 	struct net *net = genl_info_net(info);
173 
174 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
175 		ret = -EINVAL;
176 		goto out;
177 	}
178 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
179 
180 	if (!info->attrs[L2TP_ATTR_PEER_CONN_ID]) {
181 		ret = -EINVAL;
182 		goto out;
183 	}
184 	peer_tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_CONN_ID]);
185 
186 	if (!info->attrs[L2TP_ATTR_PROTO_VERSION]) {
187 		ret = -EINVAL;
188 		goto out;
189 	}
190 	proto_version = nla_get_u8(info->attrs[L2TP_ATTR_PROTO_VERSION]);
191 
192 	if (!info->attrs[L2TP_ATTR_ENCAP_TYPE]) {
193 		ret = -EINVAL;
194 		goto out;
195 	}
196 	cfg.encap = nla_get_u16(info->attrs[L2TP_ATTR_ENCAP_TYPE]);
197 
198 	fd = -1;
199 	if (info->attrs[L2TP_ATTR_FD]) {
200 		fd = nla_get_u32(info->attrs[L2TP_ATTR_FD]);
201 	} else {
202 #if IS_ENABLED(CONFIG_IPV6)
203 		if (info->attrs[L2TP_ATTR_IP6_SADDR] &&
204 		    info->attrs[L2TP_ATTR_IP6_DADDR]) {
205 			cfg.local_ip6 = nla_data(
206 				info->attrs[L2TP_ATTR_IP6_SADDR]);
207 			cfg.peer_ip6 = nla_data(
208 				info->attrs[L2TP_ATTR_IP6_DADDR]);
209 		} else
210 #endif
211 		if (info->attrs[L2TP_ATTR_IP_SADDR] &&
212 		    info->attrs[L2TP_ATTR_IP_DADDR]) {
213 			cfg.local_ip.s_addr = nla_get_in_addr(
214 				info->attrs[L2TP_ATTR_IP_SADDR]);
215 			cfg.peer_ip.s_addr = nla_get_in_addr(
216 				info->attrs[L2TP_ATTR_IP_DADDR]);
217 		} else {
218 			ret = -EINVAL;
219 			goto out;
220 		}
221 		if (info->attrs[L2TP_ATTR_UDP_SPORT])
222 			cfg.local_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_SPORT]);
223 		if (info->attrs[L2TP_ATTR_UDP_DPORT])
224 			cfg.peer_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_DPORT]);
225 		cfg.use_udp_checksums = nla_get_flag(
226 			info->attrs[L2TP_ATTR_UDP_CSUM]);
227 
228 #if IS_ENABLED(CONFIG_IPV6)
229 		cfg.udp6_zero_tx_checksums = nla_get_flag(
230 			info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_TX]);
231 		cfg.udp6_zero_rx_checksums = nla_get_flag(
232 			info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_RX]);
233 #endif
234 	}
235 
236 	if (info->attrs[L2TP_ATTR_DEBUG])
237 		cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
238 
239 	ret = -EINVAL;
240 	switch (cfg.encap) {
241 	case L2TP_ENCAPTYPE_UDP:
242 	case L2TP_ENCAPTYPE_IP:
243 		ret = l2tp_tunnel_create(net, fd, proto_version, tunnel_id,
244 					 peer_tunnel_id, &cfg, &tunnel);
245 		break;
246 	}
247 
248 	if (ret < 0)
249 		goto out;
250 
251 	l2tp_tunnel_inc_refcount(tunnel);
252 	ret = l2tp_tunnel_register(tunnel, net, &cfg);
253 	if (ret < 0) {
254 		kfree(tunnel);
255 		goto out;
256 	}
257 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info, tunnel,
258 				 L2TP_CMD_TUNNEL_CREATE);
259 	l2tp_tunnel_dec_refcount(tunnel);
260 
261 out:
262 	return ret;
263 }
264 
265 static int l2tp_nl_cmd_tunnel_delete(struct sk_buff *skb, struct genl_info *info)
266 {
267 	struct l2tp_tunnel *tunnel;
268 	u32 tunnel_id;
269 	int ret = 0;
270 	struct net *net = genl_info_net(info);
271 
272 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
273 		ret = -EINVAL;
274 		goto out;
275 	}
276 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
277 
278 	tunnel = l2tp_tunnel_get(net, tunnel_id);
279 	if (!tunnel) {
280 		ret = -ENODEV;
281 		goto out;
282 	}
283 
284 	l2tp_tunnel_notify(&l2tp_nl_family, info,
285 			   tunnel, L2TP_CMD_TUNNEL_DELETE);
286 
287 	l2tp_tunnel_delete(tunnel);
288 
289 	l2tp_tunnel_dec_refcount(tunnel);
290 
291 out:
292 	return ret;
293 }
294 
295 static int l2tp_nl_cmd_tunnel_modify(struct sk_buff *skb, struct genl_info *info)
296 {
297 	struct l2tp_tunnel *tunnel;
298 	u32 tunnel_id;
299 	int ret = 0;
300 	struct net *net = genl_info_net(info);
301 
302 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
303 		ret = -EINVAL;
304 		goto out;
305 	}
306 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
307 
308 	tunnel = l2tp_tunnel_get(net, tunnel_id);
309 	if (!tunnel) {
310 		ret = -ENODEV;
311 		goto out;
312 	}
313 
314 	if (info->attrs[L2TP_ATTR_DEBUG])
315 		tunnel->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
316 
317 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info,
318 				 tunnel, L2TP_CMD_TUNNEL_MODIFY);
319 
320 	l2tp_tunnel_dec_refcount(tunnel);
321 
322 out:
323 	return ret;
324 }
325 
326 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
327 			       struct l2tp_tunnel *tunnel, u8 cmd)
328 {
329 	void *hdr;
330 	struct nlattr *nest;
331 	struct sock *sk = NULL;
332 	struct inet_sock *inet;
333 #if IS_ENABLED(CONFIG_IPV6)
334 	struct ipv6_pinfo *np = NULL;
335 #endif
336 
337 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
338 	if (!hdr)
339 		return -EMSGSIZE;
340 
341 	if (nla_put_u8(skb, L2TP_ATTR_PROTO_VERSION, tunnel->version) ||
342 	    nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
343 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
344 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, tunnel->debug) ||
345 	    nla_put_u16(skb, L2TP_ATTR_ENCAP_TYPE, tunnel->encap))
346 		goto nla_put_failure;
347 
348 	nest = nla_nest_start(skb, L2TP_ATTR_STATS);
349 	if (nest == NULL)
350 		goto nla_put_failure;
351 
352 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
353 			      atomic_long_read(&tunnel->stats.tx_packets),
354 			      L2TP_ATTR_STATS_PAD) ||
355 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
356 			      atomic_long_read(&tunnel->stats.tx_bytes),
357 			      L2TP_ATTR_STATS_PAD) ||
358 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
359 			      atomic_long_read(&tunnel->stats.tx_errors),
360 			      L2TP_ATTR_STATS_PAD) ||
361 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
362 			      atomic_long_read(&tunnel->stats.rx_packets),
363 			      L2TP_ATTR_STATS_PAD) ||
364 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
365 			      atomic_long_read(&tunnel->stats.rx_bytes),
366 			      L2TP_ATTR_STATS_PAD) ||
367 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
368 			      atomic_long_read(&tunnel->stats.rx_seq_discards),
369 			      L2TP_ATTR_STATS_PAD) ||
370 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
371 			      atomic_long_read(&tunnel->stats.rx_oos_packets),
372 			      L2TP_ATTR_STATS_PAD) ||
373 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
374 			      atomic_long_read(&tunnel->stats.rx_errors),
375 			      L2TP_ATTR_STATS_PAD))
376 		goto nla_put_failure;
377 	nla_nest_end(skb, nest);
378 
379 	sk = tunnel->sock;
380 	if (!sk)
381 		goto out;
382 
383 #if IS_ENABLED(CONFIG_IPV6)
384 	if (sk->sk_family == AF_INET6)
385 		np = inet6_sk(sk);
386 #endif
387 
388 	inet = inet_sk(sk);
389 
390 	switch (tunnel->encap) {
391 	case L2TP_ENCAPTYPE_UDP:
392 		switch (sk->sk_family) {
393 		case AF_INET:
394 			if (nla_put_u8(skb, L2TP_ATTR_UDP_CSUM, !sk->sk_no_check_tx))
395 				goto nla_put_failure;
396 			break;
397 #if IS_ENABLED(CONFIG_IPV6)
398 		case AF_INET6:
399 			if (udp_get_no_check6_tx(sk) &&
400 			    nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_TX))
401 				goto nla_put_failure;
402 			if (udp_get_no_check6_rx(sk) &&
403 			    nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_RX))
404 				goto nla_put_failure;
405 			break;
406 #endif
407 		}
408 		if (nla_put_u16(skb, L2TP_ATTR_UDP_SPORT, ntohs(inet->inet_sport)) ||
409 		    nla_put_u16(skb, L2TP_ATTR_UDP_DPORT, ntohs(inet->inet_dport)))
410 			goto nla_put_failure;
411 		/* fall through  */
412 	case L2TP_ENCAPTYPE_IP:
413 #if IS_ENABLED(CONFIG_IPV6)
414 		if (np) {
415 			if (nla_put_in6_addr(skb, L2TP_ATTR_IP6_SADDR,
416 					     &np->saddr) ||
417 			    nla_put_in6_addr(skb, L2TP_ATTR_IP6_DADDR,
418 					     &sk->sk_v6_daddr))
419 				goto nla_put_failure;
420 		} else
421 #endif
422 		if (nla_put_in_addr(skb, L2TP_ATTR_IP_SADDR,
423 				    inet->inet_saddr) ||
424 		    nla_put_in_addr(skb, L2TP_ATTR_IP_DADDR,
425 				    inet->inet_daddr))
426 			goto nla_put_failure;
427 		break;
428 	}
429 
430 out:
431 	genlmsg_end(skb, hdr);
432 	return 0;
433 
434 nla_put_failure:
435 	genlmsg_cancel(skb, hdr);
436 	return -1;
437 }
438 
439 static int l2tp_nl_cmd_tunnel_get(struct sk_buff *skb, struct genl_info *info)
440 {
441 	struct l2tp_tunnel *tunnel;
442 	struct sk_buff *msg;
443 	u32 tunnel_id;
444 	int ret = -ENOBUFS;
445 	struct net *net = genl_info_net(info);
446 
447 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
448 		ret = -EINVAL;
449 		goto err;
450 	}
451 
452 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
453 
454 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
455 	if (!msg) {
456 		ret = -ENOMEM;
457 		goto err;
458 	}
459 
460 	tunnel = l2tp_tunnel_get(net, tunnel_id);
461 	if (!tunnel) {
462 		ret = -ENODEV;
463 		goto err_nlmsg;
464 	}
465 
466 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
467 				  NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);
468 	if (ret < 0)
469 		goto err_nlmsg_tunnel;
470 
471 	l2tp_tunnel_dec_refcount(tunnel);
472 
473 	return genlmsg_unicast(net, msg, info->snd_portid);
474 
475 err_nlmsg_tunnel:
476 	l2tp_tunnel_dec_refcount(tunnel);
477 err_nlmsg:
478 	nlmsg_free(msg);
479 err:
480 	return ret;
481 }
482 
483 static int l2tp_nl_cmd_tunnel_dump(struct sk_buff *skb, struct netlink_callback *cb)
484 {
485 	int ti = cb->args[0];
486 	struct l2tp_tunnel *tunnel;
487 	struct net *net = sock_net(skb->sk);
488 
489 	for (;;) {
490 		tunnel = l2tp_tunnel_get_nth(net, ti);
491 		if (tunnel == NULL)
492 			goto out;
493 
494 		if (l2tp_nl_tunnel_send(skb, NETLINK_CB(cb->skb).portid,
495 					cb->nlh->nlmsg_seq, NLM_F_MULTI,
496 					tunnel, L2TP_CMD_TUNNEL_GET) < 0) {
497 			l2tp_tunnel_dec_refcount(tunnel);
498 			goto out;
499 		}
500 		l2tp_tunnel_dec_refcount(tunnel);
501 
502 		ti++;
503 	}
504 
505 out:
506 	cb->args[0] = ti;
507 
508 	return skb->len;
509 }
510 
511 static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *info)
512 {
513 	u32 tunnel_id = 0;
514 	u32 session_id;
515 	u32 peer_session_id;
516 	int ret = 0;
517 	struct l2tp_tunnel *tunnel;
518 	struct l2tp_session *session;
519 	struct l2tp_session_cfg cfg = { 0, };
520 	struct net *net = genl_info_net(info);
521 
522 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
523 		ret = -EINVAL;
524 		goto out;
525 	}
526 
527 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
528 	tunnel = l2tp_tunnel_get(net, tunnel_id);
529 	if (!tunnel) {
530 		ret = -ENODEV;
531 		goto out;
532 	}
533 
534 	if (!info->attrs[L2TP_ATTR_SESSION_ID]) {
535 		ret = -EINVAL;
536 		goto out_tunnel;
537 	}
538 	session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
539 
540 	if (!info->attrs[L2TP_ATTR_PEER_SESSION_ID]) {
541 		ret = -EINVAL;
542 		goto out_tunnel;
543 	}
544 	peer_session_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_SESSION_ID]);
545 
546 	if (!info->attrs[L2TP_ATTR_PW_TYPE]) {
547 		ret = -EINVAL;
548 		goto out_tunnel;
549 	}
550 	cfg.pw_type = nla_get_u16(info->attrs[L2TP_ATTR_PW_TYPE]);
551 	if (cfg.pw_type >= __L2TP_PWTYPE_MAX) {
552 		ret = -EINVAL;
553 		goto out_tunnel;
554 	}
555 
556 	/* L2TPv2 only accepts PPP pseudo-wires */
557 	if (tunnel->version == 2 && cfg.pw_type != L2TP_PWTYPE_PPP) {
558 		ret = -EPROTONOSUPPORT;
559 		goto out_tunnel;
560 	}
561 
562 	if (tunnel->version > 2) {
563 		if (info->attrs[L2TP_ATTR_DATA_SEQ])
564 			cfg.data_seq = nla_get_u8(info->attrs[L2TP_ATTR_DATA_SEQ]);
565 
566 		if (info->attrs[L2TP_ATTR_L2SPEC_TYPE]) {
567 			cfg.l2specific_type = nla_get_u8(info->attrs[L2TP_ATTR_L2SPEC_TYPE]);
568 			if (cfg.l2specific_type != L2TP_L2SPECTYPE_DEFAULT &&
569 			    cfg.l2specific_type != L2TP_L2SPECTYPE_NONE) {
570 				ret = -EINVAL;
571 				goto out_tunnel;
572 			}
573 		} else {
574 			cfg.l2specific_type = L2TP_L2SPECTYPE_DEFAULT;
575 		}
576 
577 		if (info->attrs[L2TP_ATTR_COOKIE]) {
578 			u16 len = nla_len(info->attrs[L2TP_ATTR_COOKIE]);
579 			if (len > 8) {
580 				ret = -EINVAL;
581 				goto out_tunnel;
582 			}
583 			cfg.cookie_len = len;
584 			memcpy(&cfg.cookie[0], nla_data(info->attrs[L2TP_ATTR_COOKIE]), len);
585 		}
586 		if (info->attrs[L2TP_ATTR_PEER_COOKIE]) {
587 			u16 len = nla_len(info->attrs[L2TP_ATTR_PEER_COOKIE]);
588 			if (len > 8) {
589 				ret = -EINVAL;
590 				goto out_tunnel;
591 			}
592 			cfg.peer_cookie_len = len;
593 			memcpy(&cfg.peer_cookie[0], nla_data(info->attrs[L2TP_ATTR_PEER_COOKIE]), len);
594 		}
595 		if (info->attrs[L2TP_ATTR_IFNAME])
596 			cfg.ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
597 
598 		if (info->attrs[L2TP_ATTR_VLAN_ID])
599 			cfg.vlan_id = nla_get_u16(info->attrs[L2TP_ATTR_VLAN_ID]);
600 	}
601 
602 	if (info->attrs[L2TP_ATTR_DEBUG])
603 		cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
604 
605 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
606 		cfg.recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
607 
608 	if (info->attrs[L2TP_ATTR_SEND_SEQ])
609 		cfg.send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
610 
611 	if (info->attrs[L2TP_ATTR_LNS_MODE])
612 		cfg.lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
613 
614 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
615 		cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
616 
617 	if (info->attrs[L2TP_ATTR_MTU])
618 		cfg.mtu = nla_get_u16(info->attrs[L2TP_ATTR_MTU]);
619 
620 	if (info->attrs[L2TP_ATTR_MRU])
621 		cfg.mru = nla_get_u16(info->attrs[L2TP_ATTR_MRU]);
622 
623 #ifdef CONFIG_MODULES
624 	if (l2tp_nl_cmd_ops[cfg.pw_type] == NULL) {
625 		genl_unlock();
626 		request_module("net-l2tp-type-%u", cfg.pw_type);
627 		genl_lock();
628 	}
629 #endif
630 	if ((l2tp_nl_cmd_ops[cfg.pw_type] == NULL) ||
631 	    (l2tp_nl_cmd_ops[cfg.pw_type]->session_create == NULL)) {
632 		ret = -EPROTONOSUPPORT;
633 		goto out_tunnel;
634 	}
635 
636 	ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
637 							   session_id,
638 							   peer_session_id,
639 							   &cfg);
640 
641 	if (ret >= 0) {
642 		session = l2tp_session_get(net, tunnel, session_id);
643 		if (session) {
644 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
645 						  L2TP_CMD_SESSION_CREATE);
646 			l2tp_session_dec_refcount(session);
647 		}
648 	}
649 
650 out_tunnel:
651 	l2tp_tunnel_dec_refcount(tunnel);
652 out:
653 	return ret;
654 }
655 
656 static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *info)
657 {
658 	int ret = 0;
659 	struct l2tp_session *session;
660 	u16 pw_type;
661 
662 	session = l2tp_nl_session_get(info);
663 	if (session == NULL) {
664 		ret = -ENODEV;
665 		goto out;
666 	}
667 
668 	l2tp_session_notify(&l2tp_nl_family, info,
669 			    session, L2TP_CMD_SESSION_DELETE);
670 
671 	pw_type = session->pwtype;
672 	if (pw_type < __L2TP_PWTYPE_MAX)
673 		if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
674 			ret = (*l2tp_nl_cmd_ops[pw_type]->session_delete)(session);
675 
676 	l2tp_session_dec_refcount(session);
677 
678 out:
679 	return ret;
680 }
681 
682 static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *info)
683 {
684 	int ret = 0;
685 	struct l2tp_session *session;
686 
687 	session = l2tp_nl_session_get(info);
688 	if (session == NULL) {
689 		ret = -ENODEV;
690 		goto out;
691 	}
692 
693 	if (info->attrs[L2TP_ATTR_DEBUG])
694 		session->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
695 
696 	if (info->attrs[L2TP_ATTR_DATA_SEQ])
697 		session->data_seq = nla_get_u8(info->attrs[L2TP_ATTR_DATA_SEQ]);
698 
699 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
700 		session->recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
701 
702 	if (info->attrs[L2TP_ATTR_SEND_SEQ]) {
703 		session->send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
704 		l2tp_session_set_header_len(session, session->tunnel->version);
705 	}
706 
707 	if (info->attrs[L2TP_ATTR_LNS_MODE])
708 		session->lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
709 
710 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
711 		session->reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
712 
713 	if (info->attrs[L2TP_ATTR_MTU])
714 		session->mtu = nla_get_u16(info->attrs[L2TP_ATTR_MTU]);
715 
716 	if (info->attrs[L2TP_ATTR_MRU])
717 		session->mru = nla_get_u16(info->attrs[L2TP_ATTR_MRU]);
718 
719 	ret = l2tp_session_notify(&l2tp_nl_family, info,
720 				  session, L2TP_CMD_SESSION_MODIFY);
721 
722 	l2tp_session_dec_refcount(session);
723 
724 out:
725 	return ret;
726 }
727 
728 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
729 				struct l2tp_session *session, u8 cmd)
730 {
731 	void *hdr;
732 	struct nlattr *nest;
733 	struct l2tp_tunnel *tunnel = session->tunnel;
734 	struct sock *sk = NULL;
735 
736 	sk = tunnel->sock;
737 
738 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
739 	if (!hdr)
740 		return -EMSGSIZE;
741 
742 	if (nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
743 	    nla_put_u32(skb, L2TP_ATTR_SESSION_ID, session->session_id) ||
744 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
745 	    nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID,
746 			session->peer_session_id) ||
747 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, session->debug) ||
748 	    nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype) ||
749 	    nla_put_u16(skb, L2TP_ATTR_MTU, session->mtu) ||
750 	    (session->mru &&
751 	     nla_put_u16(skb, L2TP_ATTR_MRU, session->mru)))
752 		goto nla_put_failure;
753 
754 	if ((session->ifname[0] &&
755 	     nla_put_string(skb, L2TP_ATTR_IFNAME, session->ifname)) ||
756 	    (session->cookie_len &&
757 	     nla_put(skb, L2TP_ATTR_COOKIE, session->cookie_len,
758 		     &session->cookie[0])) ||
759 	    (session->peer_cookie_len &&
760 	     nla_put(skb, L2TP_ATTR_PEER_COOKIE, session->peer_cookie_len,
761 		     &session->peer_cookie[0])) ||
762 	    nla_put_u8(skb, L2TP_ATTR_RECV_SEQ, session->recv_seq) ||
763 	    nla_put_u8(skb, L2TP_ATTR_SEND_SEQ, session->send_seq) ||
764 	    nla_put_u8(skb, L2TP_ATTR_LNS_MODE, session->lns_mode) ||
765 #ifdef CONFIG_XFRM
766 	    (((sk) && (sk->sk_policy[0] || sk->sk_policy[1])) &&
767 	     nla_put_u8(skb, L2TP_ATTR_USING_IPSEC, 1)) ||
768 #endif
769 	    (session->reorder_timeout &&
770 	     nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT,
771 			   session->reorder_timeout, L2TP_ATTR_PAD)))
772 		goto nla_put_failure;
773 
774 	nest = nla_nest_start(skb, L2TP_ATTR_STATS);
775 	if (nest == NULL)
776 		goto nla_put_failure;
777 
778 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
779 			      atomic_long_read(&session->stats.tx_packets),
780 			      L2TP_ATTR_STATS_PAD) ||
781 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
782 			      atomic_long_read(&session->stats.tx_bytes),
783 			      L2TP_ATTR_STATS_PAD) ||
784 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
785 			      atomic_long_read(&session->stats.tx_errors),
786 			      L2TP_ATTR_STATS_PAD) ||
787 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
788 			      atomic_long_read(&session->stats.rx_packets),
789 			      L2TP_ATTR_STATS_PAD) ||
790 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
791 			      atomic_long_read(&session->stats.rx_bytes),
792 			      L2TP_ATTR_STATS_PAD) ||
793 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
794 			      atomic_long_read(&session->stats.rx_seq_discards),
795 			      L2TP_ATTR_STATS_PAD) ||
796 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
797 			      atomic_long_read(&session->stats.rx_oos_packets),
798 			      L2TP_ATTR_STATS_PAD) ||
799 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
800 			      atomic_long_read(&session->stats.rx_errors),
801 			      L2TP_ATTR_STATS_PAD))
802 		goto nla_put_failure;
803 	nla_nest_end(skb, nest);
804 
805 	genlmsg_end(skb, hdr);
806 	return 0;
807 
808  nla_put_failure:
809 	genlmsg_cancel(skb, hdr);
810 	return -1;
811 }
812 
813 static int l2tp_nl_cmd_session_get(struct sk_buff *skb, struct genl_info *info)
814 {
815 	struct l2tp_session *session;
816 	struct sk_buff *msg;
817 	int ret;
818 
819 	session = l2tp_nl_session_get(info);
820 	if (session == NULL) {
821 		ret = -ENODEV;
822 		goto err;
823 	}
824 
825 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
826 	if (!msg) {
827 		ret = -ENOMEM;
828 		goto err_ref;
829 	}
830 
831 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
832 				   0, session, L2TP_CMD_SESSION_GET);
833 	if (ret < 0)
834 		goto err_ref_msg;
835 
836 	ret = genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
837 
838 	l2tp_session_dec_refcount(session);
839 
840 	return ret;
841 
842 err_ref_msg:
843 	nlmsg_free(msg);
844 err_ref:
845 	l2tp_session_dec_refcount(session);
846 err:
847 	return ret;
848 }
849 
850 static int l2tp_nl_cmd_session_dump(struct sk_buff *skb, struct netlink_callback *cb)
851 {
852 	struct net *net = sock_net(skb->sk);
853 	struct l2tp_session *session;
854 	struct l2tp_tunnel *tunnel = NULL;
855 	int ti = cb->args[0];
856 	int si = cb->args[1];
857 
858 	for (;;) {
859 		if (tunnel == NULL) {
860 			tunnel = l2tp_tunnel_get_nth(net, ti);
861 			if (tunnel == NULL)
862 				goto out;
863 		}
864 
865 		session = l2tp_session_get_nth(tunnel, si);
866 		if (session == NULL) {
867 			ti++;
868 			l2tp_tunnel_dec_refcount(tunnel);
869 			tunnel = NULL;
870 			si = 0;
871 			continue;
872 		}
873 
874 		if (l2tp_nl_session_send(skb, NETLINK_CB(cb->skb).portid,
875 					 cb->nlh->nlmsg_seq, NLM_F_MULTI,
876 					 session, L2TP_CMD_SESSION_GET) < 0) {
877 			l2tp_session_dec_refcount(session);
878 			l2tp_tunnel_dec_refcount(tunnel);
879 			break;
880 		}
881 		l2tp_session_dec_refcount(session);
882 
883 		si++;
884 	}
885 
886 out:
887 	cb->args[0] = ti;
888 	cb->args[1] = si;
889 
890 	return skb->len;
891 }
892 
893 static const struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
894 	[L2TP_ATTR_NONE]		= { .type = NLA_UNSPEC, },
895 	[L2TP_ATTR_PW_TYPE]		= { .type = NLA_U16, },
896 	[L2TP_ATTR_ENCAP_TYPE]		= { .type = NLA_U16, },
897 	[L2TP_ATTR_OFFSET]		= { .type = NLA_U16, },
898 	[L2TP_ATTR_DATA_SEQ]		= { .type = NLA_U8, },
899 	[L2TP_ATTR_L2SPEC_TYPE]		= { .type = NLA_U8, },
900 	[L2TP_ATTR_L2SPEC_LEN]		= { .type = NLA_U8, },
901 	[L2TP_ATTR_PROTO_VERSION]	= { .type = NLA_U8, },
902 	[L2TP_ATTR_CONN_ID]		= { .type = NLA_U32, },
903 	[L2TP_ATTR_PEER_CONN_ID]	= { .type = NLA_U32, },
904 	[L2TP_ATTR_SESSION_ID]		= { .type = NLA_U32, },
905 	[L2TP_ATTR_PEER_SESSION_ID]	= { .type = NLA_U32, },
906 	[L2TP_ATTR_UDP_CSUM]		= { .type = NLA_U8, },
907 	[L2TP_ATTR_VLAN_ID]		= { .type = NLA_U16, },
908 	[L2TP_ATTR_DEBUG]		= { .type = NLA_U32, },
909 	[L2TP_ATTR_RECV_SEQ]		= { .type = NLA_U8, },
910 	[L2TP_ATTR_SEND_SEQ]		= { .type = NLA_U8, },
911 	[L2TP_ATTR_LNS_MODE]		= { .type = NLA_U8, },
912 	[L2TP_ATTR_USING_IPSEC]		= { .type = NLA_U8, },
913 	[L2TP_ATTR_RECV_TIMEOUT]	= { .type = NLA_MSECS, },
914 	[L2TP_ATTR_FD]			= { .type = NLA_U32, },
915 	[L2TP_ATTR_IP_SADDR]		= { .type = NLA_U32, },
916 	[L2TP_ATTR_IP_DADDR]		= { .type = NLA_U32, },
917 	[L2TP_ATTR_UDP_SPORT]		= { .type = NLA_U16, },
918 	[L2TP_ATTR_UDP_DPORT]		= { .type = NLA_U16, },
919 	[L2TP_ATTR_MTU]			= { .type = NLA_U16, },
920 	[L2TP_ATTR_MRU]			= { .type = NLA_U16, },
921 	[L2TP_ATTR_STATS]		= { .type = NLA_NESTED, },
922 	[L2TP_ATTR_IP6_SADDR] = {
923 		.type = NLA_BINARY,
924 		.len = sizeof(struct in6_addr),
925 	},
926 	[L2TP_ATTR_IP6_DADDR] = {
927 		.type = NLA_BINARY,
928 		.len = sizeof(struct in6_addr),
929 	},
930 	[L2TP_ATTR_IFNAME] = {
931 		.type = NLA_NUL_STRING,
932 		.len = IFNAMSIZ - 1,
933 	},
934 	[L2TP_ATTR_COOKIE] = {
935 		.type = NLA_BINARY,
936 		.len = 8,
937 	},
938 	[L2TP_ATTR_PEER_COOKIE] = {
939 		.type = NLA_BINARY,
940 		.len = 8,
941 	},
942 };
943 
944 static const struct genl_ops l2tp_nl_ops[] = {
945 	{
946 		.cmd = L2TP_CMD_NOOP,
947 		.doit = l2tp_nl_cmd_noop,
948 		.policy = l2tp_nl_policy,
949 		/* can be retrieved by unprivileged users */
950 	},
951 	{
952 		.cmd = L2TP_CMD_TUNNEL_CREATE,
953 		.doit = l2tp_nl_cmd_tunnel_create,
954 		.policy = l2tp_nl_policy,
955 		.flags = GENL_ADMIN_PERM,
956 	},
957 	{
958 		.cmd = L2TP_CMD_TUNNEL_DELETE,
959 		.doit = l2tp_nl_cmd_tunnel_delete,
960 		.policy = l2tp_nl_policy,
961 		.flags = GENL_ADMIN_PERM,
962 	},
963 	{
964 		.cmd = L2TP_CMD_TUNNEL_MODIFY,
965 		.doit = l2tp_nl_cmd_tunnel_modify,
966 		.policy = l2tp_nl_policy,
967 		.flags = GENL_ADMIN_PERM,
968 	},
969 	{
970 		.cmd = L2TP_CMD_TUNNEL_GET,
971 		.doit = l2tp_nl_cmd_tunnel_get,
972 		.dumpit = l2tp_nl_cmd_tunnel_dump,
973 		.policy = l2tp_nl_policy,
974 		.flags = GENL_ADMIN_PERM,
975 	},
976 	{
977 		.cmd = L2TP_CMD_SESSION_CREATE,
978 		.doit = l2tp_nl_cmd_session_create,
979 		.policy = l2tp_nl_policy,
980 		.flags = GENL_ADMIN_PERM,
981 	},
982 	{
983 		.cmd = L2TP_CMD_SESSION_DELETE,
984 		.doit = l2tp_nl_cmd_session_delete,
985 		.policy = l2tp_nl_policy,
986 		.flags = GENL_ADMIN_PERM,
987 	},
988 	{
989 		.cmd = L2TP_CMD_SESSION_MODIFY,
990 		.doit = l2tp_nl_cmd_session_modify,
991 		.policy = l2tp_nl_policy,
992 		.flags = GENL_ADMIN_PERM,
993 	},
994 	{
995 		.cmd = L2TP_CMD_SESSION_GET,
996 		.doit = l2tp_nl_cmd_session_get,
997 		.dumpit = l2tp_nl_cmd_session_dump,
998 		.policy = l2tp_nl_policy,
999 		.flags = GENL_ADMIN_PERM,
1000 	},
1001 };
1002 
1003 static struct genl_family l2tp_nl_family __ro_after_init = {
1004 	.name		= L2TP_GENL_NAME,
1005 	.version	= L2TP_GENL_VERSION,
1006 	.hdrsize	= 0,
1007 	.maxattr	= L2TP_ATTR_MAX,
1008 	.netnsok	= true,
1009 	.module		= THIS_MODULE,
1010 	.ops		= l2tp_nl_ops,
1011 	.n_ops		= ARRAY_SIZE(l2tp_nl_ops),
1012 	.mcgrps		= l2tp_multicast_group,
1013 	.n_mcgrps	= ARRAY_SIZE(l2tp_multicast_group),
1014 };
1015 
1016 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops)
1017 {
1018 	int ret;
1019 
1020 	ret = -EINVAL;
1021 	if (pw_type >= __L2TP_PWTYPE_MAX)
1022 		goto err;
1023 
1024 	genl_lock();
1025 	ret = -EBUSY;
1026 	if (l2tp_nl_cmd_ops[pw_type])
1027 		goto out;
1028 
1029 	l2tp_nl_cmd_ops[pw_type] = ops;
1030 	ret = 0;
1031 
1032 out:
1033 	genl_unlock();
1034 err:
1035 	return ret;
1036 }
1037 EXPORT_SYMBOL_GPL(l2tp_nl_register_ops);
1038 
1039 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type)
1040 {
1041 	if (pw_type < __L2TP_PWTYPE_MAX) {
1042 		genl_lock();
1043 		l2tp_nl_cmd_ops[pw_type] = NULL;
1044 		genl_unlock();
1045 	}
1046 }
1047 EXPORT_SYMBOL_GPL(l2tp_nl_unregister_ops);
1048 
1049 static int __init l2tp_nl_init(void)
1050 {
1051 	pr_info("L2TP netlink interface\n");
1052 	return genl_register_family(&l2tp_nl_family);
1053 }
1054 
1055 static void l2tp_nl_cleanup(void)
1056 {
1057 	genl_unregister_family(&l2tp_nl_family);
1058 }
1059 
1060 module_init(l2tp_nl_init);
1061 module_exit(l2tp_nl_cleanup);
1062 
1063 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1064 MODULE_DESCRIPTION("L2TP netlink");
1065 MODULE_LICENSE("GPL");
1066 MODULE_VERSION("1.0");
1067 MODULE_ALIAS_GENL_FAMILY("l2tp");
1068