xref: /openbmc/linux/net/l2tp/l2tp_netlink.c (revision eb7ebfa3) 
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_tunnel_get_session(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_L2SPEC_TYPE]) {
564 			cfg.l2specific_type = nla_get_u8(info->attrs[L2TP_ATTR_L2SPEC_TYPE]);
565 			if (cfg.l2specific_type != L2TP_L2SPECTYPE_DEFAULT &&
566 			    cfg.l2specific_type != L2TP_L2SPECTYPE_NONE) {
567 				ret = -EINVAL;
568 				goto out_tunnel;
569 			}
570 		} else {
571 			cfg.l2specific_type = L2TP_L2SPECTYPE_DEFAULT;
572 		}
573 
574 		if (info->attrs[L2TP_ATTR_COOKIE]) {
575 			u16 len = nla_len(info->attrs[L2TP_ATTR_COOKIE]);
576 			if (len > 8) {
577 				ret = -EINVAL;
578 				goto out_tunnel;
579 			}
580 			cfg.cookie_len = len;
581 			memcpy(&cfg.cookie[0], nla_data(info->attrs[L2TP_ATTR_COOKIE]), len);
582 		}
583 		if (info->attrs[L2TP_ATTR_PEER_COOKIE]) {
584 			u16 len = nla_len(info->attrs[L2TP_ATTR_PEER_COOKIE]);
585 			if (len > 8) {
586 				ret = -EINVAL;
587 				goto out_tunnel;
588 			}
589 			cfg.peer_cookie_len = len;
590 			memcpy(&cfg.peer_cookie[0], nla_data(info->attrs[L2TP_ATTR_PEER_COOKIE]), len);
591 		}
592 		if (info->attrs[L2TP_ATTR_IFNAME])
593 			cfg.ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
594 	}
595 
596 	if (info->attrs[L2TP_ATTR_DEBUG])
597 		cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
598 
599 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
600 		cfg.recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
601 
602 	if (info->attrs[L2TP_ATTR_SEND_SEQ])
603 		cfg.send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
604 
605 	if (info->attrs[L2TP_ATTR_LNS_MODE])
606 		cfg.lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
607 
608 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
609 		cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
610 
611 #ifdef CONFIG_MODULES
612 	if (l2tp_nl_cmd_ops[cfg.pw_type] == NULL) {
613 		genl_unlock();
614 		request_module("net-l2tp-type-%u", cfg.pw_type);
615 		genl_lock();
616 	}
617 #endif
618 	if ((l2tp_nl_cmd_ops[cfg.pw_type] == NULL) ||
619 	    (l2tp_nl_cmd_ops[cfg.pw_type]->session_create == NULL)) {
620 		ret = -EPROTONOSUPPORT;
621 		goto out_tunnel;
622 	}
623 
624 	ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
625 							   session_id,
626 							   peer_session_id,
627 							   &cfg);
628 
629 	if (ret >= 0) {
630 		session = l2tp_tunnel_get_session(tunnel, session_id);
631 		if (session) {
632 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
633 						  L2TP_CMD_SESSION_CREATE);
634 			l2tp_session_dec_refcount(session);
635 		}
636 	}
637 
638 out_tunnel:
639 	l2tp_tunnel_dec_refcount(tunnel);
640 out:
641 	return ret;
642 }
643 
644 static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *info)
645 {
646 	int ret = 0;
647 	struct l2tp_session *session;
648 	u16 pw_type;
649 
650 	session = l2tp_nl_session_get(info);
651 	if (session == NULL) {
652 		ret = -ENODEV;
653 		goto out;
654 	}
655 
656 	l2tp_session_notify(&l2tp_nl_family, info,
657 			    session, L2TP_CMD_SESSION_DELETE);
658 
659 	pw_type = session->pwtype;
660 	if (pw_type < __L2TP_PWTYPE_MAX)
661 		if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
662 			ret = (*l2tp_nl_cmd_ops[pw_type]->session_delete)(session);
663 
664 	l2tp_session_dec_refcount(session);
665 
666 out:
667 	return ret;
668 }
669 
670 static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *info)
671 {
672 	int ret = 0;
673 	struct l2tp_session *session;
674 
675 	session = l2tp_nl_session_get(info);
676 	if (session == NULL) {
677 		ret = -ENODEV;
678 		goto out;
679 	}
680 
681 	if (info->attrs[L2TP_ATTR_DEBUG])
682 		session->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
683 
684 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
685 		session->recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
686 
687 	if (info->attrs[L2TP_ATTR_SEND_SEQ]) {
688 		session->send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
689 		l2tp_session_set_header_len(session, session->tunnel->version);
690 	}
691 
692 	if (info->attrs[L2TP_ATTR_LNS_MODE])
693 		session->lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
694 
695 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
696 		session->reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
697 
698 	ret = l2tp_session_notify(&l2tp_nl_family, info,
699 				  session, L2TP_CMD_SESSION_MODIFY);
700 
701 	l2tp_session_dec_refcount(session);
702 
703 out:
704 	return ret;
705 }
706 
707 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
708 				struct l2tp_session *session, u8 cmd)
709 {
710 	void *hdr;
711 	struct nlattr *nest;
712 	struct l2tp_tunnel *tunnel = session->tunnel;
713 
714 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
715 	if (!hdr)
716 		return -EMSGSIZE;
717 
718 	if (nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
719 	    nla_put_u32(skb, L2TP_ATTR_SESSION_ID, session->session_id) ||
720 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
721 	    nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID,
722 			session->peer_session_id) ||
723 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, session->debug) ||
724 	    nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype))
725 		goto nla_put_failure;
726 
727 	if ((session->ifname[0] &&
728 	     nla_put_string(skb, L2TP_ATTR_IFNAME, session->ifname)) ||
729 	    (session->cookie_len &&
730 	     nla_put(skb, L2TP_ATTR_COOKIE, session->cookie_len,
731 		     &session->cookie[0])) ||
732 	    (session->peer_cookie_len &&
733 	     nla_put(skb, L2TP_ATTR_PEER_COOKIE, session->peer_cookie_len,
734 		     &session->peer_cookie[0])) ||
735 	    nla_put_u8(skb, L2TP_ATTR_RECV_SEQ, session->recv_seq) ||
736 	    nla_put_u8(skb, L2TP_ATTR_SEND_SEQ, session->send_seq) ||
737 	    nla_put_u8(skb, L2TP_ATTR_LNS_MODE, session->lns_mode) ||
738 	    (l2tp_tunnel_uses_xfrm(tunnel) &&
739 	     nla_put_u8(skb, L2TP_ATTR_USING_IPSEC, 1)) ||
740 	    (session->reorder_timeout &&
741 	     nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT,
742 			   session->reorder_timeout, L2TP_ATTR_PAD)))
743 		goto nla_put_failure;
744 
745 	nest = nla_nest_start(skb, L2TP_ATTR_STATS);
746 	if (nest == NULL)
747 		goto nla_put_failure;
748 
749 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
750 			      atomic_long_read(&session->stats.tx_packets),
751 			      L2TP_ATTR_STATS_PAD) ||
752 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
753 			      atomic_long_read(&session->stats.tx_bytes),
754 			      L2TP_ATTR_STATS_PAD) ||
755 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
756 			      atomic_long_read(&session->stats.tx_errors),
757 			      L2TP_ATTR_STATS_PAD) ||
758 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
759 			      atomic_long_read(&session->stats.rx_packets),
760 			      L2TP_ATTR_STATS_PAD) ||
761 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
762 			      atomic_long_read(&session->stats.rx_bytes),
763 			      L2TP_ATTR_STATS_PAD) ||
764 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
765 			      atomic_long_read(&session->stats.rx_seq_discards),
766 			      L2TP_ATTR_STATS_PAD) ||
767 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
768 			      atomic_long_read(&session->stats.rx_oos_packets),
769 			      L2TP_ATTR_STATS_PAD) ||
770 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
771 			      atomic_long_read(&session->stats.rx_errors),
772 			      L2TP_ATTR_STATS_PAD))
773 		goto nla_put_failure;
774 	nla_nest_end(skb, nest);
775 
776 	genlmsg_end(skb, hdr);
777 	return 0;
778 
779  nla_put_failure:
780 	genlmsg_cancel(skb, hdr);
781 	return -1;
782 }
783 
784 static int l2tp_nl_cmd_session_get(struct sk_buff *skb, struct genl_info *info)
785 {
786 	struct l2tp_session *session;
787 	struct sk_buff *msg;
788 	int ret;
789 
790 	session = l2tp_nl_session_get(info);
791 	if (session == NULL) {
792 		ret = -ENODEV;
793 		goto err;
794 	}
795 
796 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
797 	if (!msg) {
798 		ret = -ENOMEM;
799 		goto err_ref;
800 	}
801 
802 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
803 				   0, session, L2TP_CMD_SESSION_GET);
804 	if (ret < 0)
805 		goto err_ref_msg;
806 
807 	ret = genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
808 
809 	l2tp_session_dec_refcount(session);
810 
811 	return ret;
812 
813 err_ref_msg:
814 	nlmsg_free(msg);
815 err_ref:
816 	l2tp_session_dec_refcount(session);
817 err:
818 	return ret;
819 }
820 
821 static int l2tp_nl_cmd_session_dump(struct sk_buff *skb, struct netlink_callback *cb)
822 {
823 	struct net *net = sock_net(skb->sk);
824 	struct l2tp_session *session;
825 	struct l2tp_tunnel *tunnel = NULL;
826 	int ti = cb->args[0];
827 	int si = cb->args[1];
828 
829 	for (;;) {
830 		if (tunnel == NULL) {
831 			tunnel = l2tp_tunnel_get_nth(net, ti);
832 			if (tunnel == NULL)
833 				goto out;
834 		}
835 
836 		session = l2tp_session_get_nth(tunnel, si);
837 		if (session == NULL) {
838 			ti++;
839 			l2tp_tunnel_dec_refcount(tunnel);
840 			tunnel = NULL;
841 			si = 0;
842 			continue;
843 		}
844 
845 		if (l2tp_nl_session_send(skb, NETLINK_CB(cb->skb).portid,
846 					 cb->nlh->nlmsg_seq, NLM_F_MULTI,
847 					 session, L2TP_CMD_SESSION_GET) < 0) {
848 			l2tp_session_dec_refcount(session);
849 			l2tp_tunnel_dec_refcount(tunnel);
850 			break;
851 		}
852 		l2tp_session_dec_refcount(session);
853 
854 		si++;
855 	}
856 
857 out:
858 	cb->args[0] = ti;
859 	cb->args[1] = si;
860 
861 	return skb->len;
862 }
863 
864 static const struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
865 	[L2TP_ATTR_NONE]		= { .type = NLA_UNSPEC, },
866 	[L2TP_ATTR_PW_TYPE]		= { .type = NLA_U16, },
867 	[L2TP_ATTR_ENCAP_TYPE]		= { .type = NLA_U16, },
868 	[L2TP_ATTR_OFFSET]		= { .type = NLA_U16, },
869 	[L2TP_ATTR_DATA_SEQ]		= { .type = NLA_U8, },
870 	[L2TP_ATTR_L2SPEC_TYPE]		= { .type = NLA_U8, },
871 	[L2TP_ATTR_L2SPEC_LEN]		= { .type = NLA_U8, },
872 	[L2TP_ATTR_PROTO_VERSION]	= { .type = NLA_U8, },
873 	[L2TP_ATTR_CONN_ID]		= { .type = NLA_U32, },
874 	[L2TP_ATTR_PEER_CONN_ID]	= { .type = NLA_U32, },
875 	[L2TP_ATTR_SESSION_ID]		= { .type = NLA_U32, },
876 	[L2TP_ATTR_PEER_SESSION_ID]	= { .type = NLA_U32, },
877 	[L2TP_ATTR_UDP_CSUM]		= { .type = NLA_U8, },
878 	[L2TP_ATTR_VLAN_ID]		= { .type = NLA_U16, },
879 	[L2TP_ATTR_DEBUG]		= { .type = NLA_U32, },
880 	[L2TP_ATTR_RECV_SEQ]		= { .type = NLA_U8, },
881 	[L2TP_ATTR_SEND_SEQ]		= { .type = NLA_U8, },
882 	[L2TP_ATTR_LNS_MODE]		= { .type = NLA_U8, },
883 	[L2TP_ATTR_USING_IPSEC]		= { .type = NLA_U8, },
884 	[L2TP_ATTR_RECV_TIMEOUT]	= { .type = NLA_MSECS, },
885 	[L2TP_ATTR_FD]			= { .type = NLA_U32, },
886 	[L2TP_ATTR_IP_SADDR]		= { .type = NLA_U32, },
887 	[L2TP_ATTR_IP_DADDR]		= { .type = NLA_U32, },
888 	[L2TP_ATTR_UDP_SPORT]		= { .type = NLA_U16, },
889 	[L2TP_ATTR_UDP_DPORT]		= { .type = NLA_U16, },
890 	[L2TP_ATTR_MTU]			= { .type = NLA_U16, },
891 	[L2TP_ATTR_MRU]			= { .type = NLA_U16, },
892 	[L2TP_ATTR_STATS]		= { .type = NLA_NESTED, },
893 	[L2TP_ATTR_IP6_SADDR] = {
894 		.type = NLA_BINARY,
895 		.len = sizeof(struct in6_addr),
896 	},
897 	[L2TP_ATTR_IP6_DADDR] = {
898 		.type = NLA_BINARY,
899 		.len = sizeof(struct in6_addr),
900 	},
901 	[L2TP_ATTR_IFNAME] = {
902 		.type = NLA_NUL_STRING,
903 		.len = IFNAMSIZ - 1,
904 	},
905 	[L2TP_ATTR_COOKIE] = {
906 		.type = NLA_BINARY,
907 		.len = 8,
908 	},
909 	[L2TP_ATTR_PEER_COOKIE] = {
910 		.type = NLA_BINARY,
911 		.len = 8,
912 	},
913 };
914 
915 static const struct genl_ops l2tp_nl_ops[] = {
916 	{
917 		.cmd = L2TP_CMD_NOOP,
918 		.doit = l2tp_nl_cmd_noop,
919 		.policy = l2tp_nl_policy,
920 		/* can be retrieved by unprivileged users */
921 	},
922 	{
923 		.cmd = L2TP_CMD_TUNNEL_CREATE,
924 		.doit = l2tp_nl_cmd_tunnel_create,
925 		.policy = l2tp_nl_policy,
926 		.flags = GENL_ADMIN_PERM,
927 	},
928 	{
929 		.cmd = L2TP_CMD_TUNNEL_DELETE,
930 		.doit = l2tp_nl_cmd_tunnel_delete,
931 		.policy = l2tp_nl_policy,
932 		.flags = GENL_ADMIN_PERM,
933 	},
934 	{
935 		.cmd = L2TP_CMD_TUNNEL_MODIFY,
936 		.doit = l2tp_nl_cmd_tunnel_modify,
937 		.policy = l2tp_nl_policy,
938 		.flags = GENL_ADMIN_PERM,
939 	},
940 	{
941 		.cmd = L2TP_CMD_TUNNEL_GET,
942 		.doit = l2tp_nl_cmd_tunnel_get,
943 		.dumpit = l2tp_nl_cmd_tunnel_dump,
944 		.policy = l2tp_nl_policy,
945 		.flags = GENL_ADMIN_PERM,
946 	},
947 	{
948 		.cmd = L2TP_CMD_SESSION_CREATE,
949 		.doit = l2tp_nl_cmd_session_create,
950 		.policy = l2tp_nl_policy,
951 		.flags = GENL_ADMIN_PERM,
952 	},
953 	{
954 		.cmd = L2TP_CMD_SESSION_DELETE,
955 		.doit = l2tp_nl_cmd_session_delete,
956 		.policy = l2tp_nl_policy,
957 		.flags = GENL_ADMIN_PERM,
958 	},
959 	{
960 		.cmd = L2TP_CMD_SESSION_MODIFY,
961 		.doit = l2tp_nl_cmd_session_modify,
962 		.policy = l2tp_nl_policy,
963 		.flags = GENL_ADMIN_PERM,
964 	},
965 	{
966 		.cmd = L2TP_CMD_SESSION_GET,
967 		.doit = l2tp_nl_cmd_session_get,
968 		.dumpit = l2tp_nl_cmd_session_dump,
969 		.policy = l2tp_nl_policy,
970 		.flags = GENL_ADMIN_PERM,
971 	},
972 };
973 
974 static struct genl_family l2tp_nl_family __ro_after_init = {
975 	.name		= L2TP_GENL_NAME,
976 	.version	= L2TP_GENL_VERSION,
977 	.hdrsize	= 0,
978 	.maxattr	= L2TP_ATTR_MAX,
979 	.netnsok	= true,
980 	.module		= THIS_MODULE,
981 	.ops		= l2tp_nl_ops,
982 	.n_ops		= ARRAY_SIZE(l2tp_nl_ops),
983 	.mcgrps		= l2tp_multicast_group,
984 	.n_mcgrps	= ARRAY_SIZE(l2tp_multicast_group),
985 };
986 
987 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops)
988 {
989 	int ret;
990 
991 	ret = -EINVAL;
992 	if (pw_type >= __L2TP_PWTYPE_MAX)
993 		goto err;
994 
995 	genl_lock();
996 	ret = -EBUSY;
997 	if (l2tp_nl_cmd_ops[pw_type])
998 		goto out;
999 
1000 	l2tp_nl_cmd_ops[pw_type] = ops;
1001 	ret = 0;
1002 
1003 out:
1004 	genl_unlock();
1005 err:
1006 	return ret;
1007 }
1008 EXPORT_SYMBOL_GPL(l2tp_nl_register_ops);
1009 
1010 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type)
1011 {
1012 	if (pw_type < __L2TP_PWTYPE_MAX) {
1013 		genl_lock();
1014 		l2tp_nl_cmd_ops[pw_type] = NULL;
1015 		genl_unlock();
1016 	}
1017 }
1018 EXPORT_SYMBOL_GPL(l2tp_nl_unregister_ops);
1019 
1020 static int __init l2tp_nl_init(void)
1021 {
1022 	pr_info("L2TP netlink interface\n");
1023 	return genl_register_family(&l2tp_nl_family);
1024 }
1025 
1026 static void l2tp_nl_cleanup(void)
1027 {
1028 	genl_unregister_family(&l2tp_nl_family);
1029 }
1030 
1031 module_init(l2tp_nl_init);
1032 module_exit(l2tp_nl_cleanup);
1033 
1034 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1035 MODULE_DESCRIPTION("L2TP netlink");
1036 MODULE_LICENSE("GPL");
1037 MODULE_VERSION("1.0");
1038 MODULE_ALIAS_GENL_FAMILY("l2tp");
1039