xref: /openbmc/linux/net/l2tp/l2tp_netlink.c (revision adb57164) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * L2TP netlink layer, for management
4  *
5  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
6  *
7  * Partly based on the IrDA nelink implementation
8  * (see net/irda/irnetlink.c) which is:
9  * Copyright (c) 2007 Samuel Ortiz <samuel@sortiz.org>
10  * which is in turn partly based on the wireless netlink code:
11  * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
12  */
13 
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 
16 #include <net/sock.h>
17 #include <net/genetlink.h>
18 #include <net/udp.h>
19 #include <linux/in.h>
20 #include <linux/udp.h>
21 #include <linux/socket.h>
22 #include <linux/module.h>
23 #include <linux/list.h>
24 #include <net/net_namespace.h>
25 
26 #include <linux/l2tp.h>
27 
28 #include "l2tp_core.h"
29 
30 
31 static struct genl_family l2tp_nl_family;
32 
33 static const struct genl_multicast_group l2tp_multicast_group[] = {
34 	{
35 		.name = L2TP_GENL_MCGROUP,
36 	},
37 };
38 
39 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq,
40 			       int flags, struct l2tp_tunnel *tunnel, u8 cmd);
41 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq,
42 				int flags, struct l2tp_session *session,
43 				u8 cmd);
44 
45 /* Accessed under genl lock */
46 static const struct l2tp_nl_cmd_ops *l2tp_nl_cmd_ops[__L2TP_PWTYPE_MAX];
47 
48 static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
49 {
50 	u32 tunnel_id;
51 	u32 session_id;
52 	char *ifname;
53 	struct l2tp_tunnel *tunnel;
54 	struct l2tp_session *session = NULL;
55 	struct net *net = genl_info_net(info);
56 
57 	if (info->attrs[L2TP_ATTR_IFNAME]) {
58 		ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
59 		session = l2tp_session_get_by_ifname(net, ifname);
60 	} else if ((info->attrs[L2TP_ATTR_SESSION_ID]) &&
61 		   (info->attrs[L2TP_ATTR_CONN_ID])) {
62 		tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
63 		session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
64 		tunnel = l2tp_tunnel_get(net, tunnel_id);
65 		if (tunnel) {
66 			session = l2tp_tunnel_get_session(tunnel, session_id);
67 			l2tp_tunnel_dec_refcount(tunnel);
68 		}
69 	}
70 
71 	return session;
72 }
73 
74 static int l2tp_nl_cmd_noop(struct sk_buff *skb, struct genl_info *info)
75 {
76 	struct sk_buff *msg;
77 	void *hdr;
78 	int ret = -ENOBUFS;
79 
80 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
81 	if (!msg) {
82 		ret = -ENOMEM;
83 		goto out;
84 	}
85 
86 	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
87 			  &l2tp_nl_family, 0, L2TP_CMD_NOOP);
88 	if (!hdr) {
89 		ret = -EMSGSIZE;
90 		goto err_out;
91 	}
92 
93 	genlmsg_end(msg, hdr);
94 
95 	return genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
96 
97 err_out:
98 	nlmsg_free(msg);
99 
100 out:
101 	return ret;
102 }
103 
104 static int l2tp_tunnel_notify(struct genl_family *family,
105 			      struct genl_info *info,
106 			      struct l2tp_tunnel *tunnel,
107 			      u8 cmd)
108 {
109 	struct sk_buff *msg;
110 	int ret;
111 
112 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
113 	if (!msg)
114 		return -ENOMEM;
115 
116 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
117 				  NLM_F_ACK, tunnel, cmd);
118 
119 	if (ret >= 0) {
120 		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
121 		/* We don't care if no one is listening */
122 		if (ret == -ESRCH)
123 			ret = 0;
124 		return ret;
125 	}
126 
127 	nlmsg_free(msg);
128 
129 	return ret;
130 }
131 
132 static int l2tp_session_notify(struct genl_family *family,
133 			       struct genl_info *info,
134 			       struct l2tp_session *session,
135 			       u8 cmd)
136 {
137 	struct sk_buff *msg;
138 	int ret;
139 
140 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
141 	if (!msg)
142 		return -ENOMEM;
143 
144 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
145 				   NLM_F_ACK, session, cmd);
146 
147 	if (ret >= 0) {
148 		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
149 		/* We don't care if no one is listening */
150 		if (ret == -ESRCH)
151 			ret = 0;
152 		return ret;
153 	}
154 
155 	nlmsg_free(msg);
156 
157 	return ret;
158 }
159 
160 static int l2tp_nl_cmd_tunnel_create(struct sk_buff *skb, struct genl_info *info)
161 {
162 	u32 tunnel_id;
163 	u32 peer_tunnel_id;
164 	int proto_version;
165 	int fd;
166 	int ret = 0;
167 	struct l2tp_tunnel_cfg cfg = { 0, };
168 	struct l2tp_tunnel *tunnel;
169 	struct net *net = genl_info_net(info);
170 
171 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
172 		ret = -EINVAL;
173 		goto out;
174 	}
175 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
176 
177 	if (!info->attrs[L2TP_ATTR_PEER_CONN_ID]) {
178 		ret = -EINVAL;
179 		goto out;
180 	}
181 	peer_tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_CONN_ID]);
182 
183 	if (!info->attrs[L2TP_ATTR_PROTO_VERSION]) {
184 		ret = -EINVAL;
185 		goto out;
186 	}
187 	proto_version = nla_get_u8(info->attrs[L2TP_ATTR_PROTO_VERSION]);
188 
189 	if (!info->attrs[L2TP_ATTR_ENCAP_TYPE]) {
190 		ret = -EINVAL;
191 		goto out;
192 	}
193 	cfg.encap = nla_get_u16(info->attrs[L2TP_ATTR_ENCAP_TYPE]);
194 
195 	fd = -1;
196 	if (info->attrs[L2TP_ATTR_FD]) {
197 		fd = nla_get_u32(info->attrs[L2TP_ATTR_FD]);
198 	} else {
199 #if IS_ENABLED(CONFIG_IPV6)
200 		if (info->attrs[L2TP_ATTR_IP6_SADDR] &&
201 		    info->attrs[L2TP_ATTR_IP6_DADDR]) {
202 			cfg.local_ip6 = nla_data(
203 				info->attrs[L2TP_ATTR_IP6_SADDR]);
204 			cfg.peer_ip6 = nla_data(
205 				info->attrs[L2TP_ATTR_IP6_DADDR]);
206 		} else
207 #endif
208 		if (info->attrs[L2TP_ATTR_IP_SADDR] &&
209 		    info->attrs[L2TP_ATTR_IP_DADDR]) {
210 			cfg.local_ip.s_addr = nla_get_in_addr(
211 				info->attrs[L2TP_ATTR_IP_SADDR]);
212 			cfg.peer_ip.s_addr = nla_get_in_addr(
213 				info->attrs[L2TP_ATTR_IP_DADDR]);
214 		} else {
215 			ret = -EINVAL;
216 			goto out;
217 		}
218 		if (info->attrs[L2TP_ATTR_UDP_SPORT])
219 			cfg.local_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_SPORT]);
220 		if (info->attrs[L2TP_ATTR_UDP_DPORT])
221 			cfg.peer_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_DPORT]);
222 		cfg.use_udp_checksums = nla_get_flag(
223 			info->attrs[L2TP_ATTR_UDP_CSUM]);
224 
225 #if IS_ENABLED(CONFIG_IPV6)
226 		cfg.udp6_zero_tx_checksums = nla_get_flag(
227 			info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_TX]);
228 		cfg.udp6_zero_rx_checksums = nla_get_flag(
229 			info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_RX]);
230 #endif
231 	}
232 
233 	if (info->attrs[L2TP_ATTR_DEBUG])
234 		cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
235 
236 	ret = -EINVAL;
237 	switch (cfg.encap) {
238 	case L2TP_ENCAPTYPE_UDP:
239 	case L2TP_ENCAPTYPE_IP:
240 		ret = l2tp_tunnel_create(net, fd, proto_version, tunnel_id,
241 					 peer_tunnel_id, &cfg, &tunnel);
242 		break;
243 	}
244 
245 	if (ret < 0)
246 		goto out;
247 
248 	l2tp_tunnel_inc_refcount(tunnel);
249 	ret = l2tp_tunnel_register(tunnel, net, &cfg);
250 	if (ret < 0) {
251 		kfree(tunnel);
252 		goto out;
253 	}
254 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info, tunnel,
255 				 L2TP_CMD_TUNNEL_CREATE);
256 	l2tp_tunnel_dec_refcount(tunnel);
257 
258 out:
259 	return ret;
260 }
261 
262 static int l2tp_nl_cmd_tunnel_delete(struct sk_buff *skb, struct genl_info *info)
263 {
264 	struct l2tp_tunnel *tunnel;
265 	u32 tunnel_id;
266 	int ret = 0;
267 	struct net *net = genl_info_net(info);
268 
269 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
270 		ret = -EINVAL;
271 		goto out;
272 	}
273 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
274 
275 	tunnel = l2tp_tunnel_get(net, tunnel_id);
276 	if (!tunnel) {
277 		ret = -ENODEV;
278 		goto out;
279 	}
280 
281 	l2tp_tunnel_notify(&l2tp_nl_family, info,
282 			   tunnel, L2TP_CMD_TUNNEL_DELETE);
283 
284 	l2tp_tunnel_delete(tunnel);
285 
286 	l2tp_tunnel_dec_refcount(tunnel);
287 
288 out:
289 	return ret;
290 }
291 
292 static int l2tp_nl_cmd_tunnel_modify(struct sk_buff *skb, struct genl_info *info)
293 {
294 	struct l2tp_tunnel *tunnel;
295 	u32 tunnel_id;
296 	int ret = 0;
297 	struct net *net = genl_info_net(info);
298 
299 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
300 		ret = -EINVAL;
301 		goto out;
302 	}
303 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
304 
305 	tunnel = l2tp_tunnel_get(net, tunnel_id);
306 	if (!tunnel) {
307 		ret = -ENODEV;
308 		goto out;
309 	}
310 
311 	if (info->attrs[L2TP_ATTR_DEBUG])
312 		tunnel->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
313 
314 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info,
315 				 tunnel, L2TP_CMD_TUNNEL_MODIFY);
316 
317 	l2tp_tunnel_dec_refcount(tunnel);
318 
319 out:
320 	return ret;
321 }
322 
323 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
324 			       struct l2tp_tunnel *tunnel, u8 cmd)
325 {
326 	void *hdr;
327 	struct nlattr *nest;
328 	struct sock *sk = NULL;
329 	struct inet_sock *inet;
330 #if IS_ENABLED(CONFIG_IPV6)
331 	struct ipv6_pinfo *np = NULL;
332 #endif
333 
334 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
335 	if (!hdr)
336 		return -EMSGSIZE;
337 
338 	if (nla_put_u8(skb, L2TP_ATTR_PROTO_VERSION, tunnel->version) ||
339 	    nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
340 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
341 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, tunnel->debug) ||
342 	    nla_put_u16(skb, L2TP_ATTR_ENCAP_TYPE, tunnel->encap))
343 		goto nla_put_failure;
344 
345 	nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
346 	if (nest == NULL)
347 		goto nla_put_failure;
348 
349 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
350 			      atomic_long_read(&tunnel->stats.tx_packets),
351 			      L2TP_ATTR_STATS_PAD) ||
352 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
353 			      atomic_long_read(&tunnel->stats.tx_bytes),
354 			      L2TP_ATTR_STATS_PAD) ||
355 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
356 			      atomic_long_read(&tunnel->stats.tx_errors),
357 			      L2TP_ATTR_STATS_PAD) ||
358 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
359 			      atomic_long_read(&tunnel->stats.rx_packets),
360 			      L2TP_ATTR_STATS_PAD) ||
361 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
362 			      atomic_long_read(&tunnel->stats.rx_bytes),
363 			      L2TP_ATTR_STATS_PAD) ||
364 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
365 			      atomic_long_read(&tunnel->stats.rx_seq_discards),
366 			      L2TP_ATTR_STATS_PAD) ||
367 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
368 			      atomic_long_read(&tunnel->stats.rx_oos_packets),
369 			      L2TP_ATTR_STATS_PAD) ||
370 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
371 			      atomic_long_read(&tunnel->stats.rx_errors),
372 			      L2TP_ATTR_STATS_PAD))
373 		goto nla_put_failure;
374 	nla_nest_end(skb, nest);
375 
376 	sk = tunnel->sock;
377 	if (!sk)
378 		goto out;
379 
380 #if IS_ENABLED(CONFIG_IPV6)
381 	if (sk->sk_family == AF_INET6)
382 		np = inet6_sk(sk);
383 #endif
384 
385 	inet = inet_sk(sk);
386 
387 	switch (tunnel->encap) {
388 	case L2TP_ENCAPTYPE_UDP:
389 		switch (sk->sk_family) {
390 		case AF_INET:
391 			if (nla_put_u8(skb, L2TP_ATTR_UDP_CSUM, !sk->sk_no_check_tx))
392 				goto nla_put_failure;
393 			break;
394 #if IS_ENABLED(CONFIG_IPV6)
395 		case AF_INET6:
396 			if (udp_get_no_check6_tx(sk) &&
397 			    nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_TX))
398 				goto nla_put_failure;
399 			if (udp_get_no_check6_rx(sk) &&
400 			    nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_RX))
401 				goto nla_put_failure;
402 			break;
403 #endif
404 		}
405 		if (nla_put_u16(skb, L2TP_ATTR_UDP_SPORT, ntohs(inet->inet_sport)) ||
406 		    nla_put_u16(skb, L2TP_ATTR_UDP_DPORT, ntohs(inet->inet_dport)))
407 			goto nla_put_failure;
408 		/* fall through  */
409 	case L2TP_ENCAPTYPE_IP:
410 #if IS_ENABLED(CONFIG_IPV6)
411 		if (np) {
412 			if (nla_put_in6_addr(skb, L2TP_ATTR_IP6_SADDR,
413 					     &np->saddr) ||
414 			    nla_put_in6_addr(skb, L2TP_ATTR_IP6_DADDR,
415 					     &sk->sk_v6_daddr))
416 				goto nla_put_failure;
417 		} else
418 #endif
419 		if (nla_put_in_addr(skb, L2TP_ATTR_IP_SADDR,
420 				    inet->inet_saddr) ||
421 		    nla_put_in_addr(skb, L2TP_ATTR_IP_DADDR,
422 				    inet->inet_daddr))
423 			goto nla_put_failure;
424 		break;
425 	}
426 
427 out:
428 	genlmsg_end(skb, hdr);
429 	return 0;
430 
431 nla_put_failure:
432 	genlmsg_cancel(skb, hdr);
433 	return -1;
434 }
435 
436 static int l2tp_nl_cmd_tunnel_get(struct sk_buff *skb, struct genl_info *info)
437 {
438 	struct l2tp_tunnel *tunnel;
439 	struct sk_buff *msg;
440 	u32 tunnel_id;
441 	int ret = -ENOBUFS;
442 	struct net *net = genl_info_net(info);
443 
444 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
445 		ret = -EINVAL;
446 		goto err;
447 	}
448 
449 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
450 
451 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
452 	if (!msg) {
453 		ret = -ENOMEM;
454 		goto err;
455 	}
456 
457 	tunnel = l2tp_tunnel_get(net, tunnel_id);
458 	if (!tunnel) {
459 		ret = -ENODEV;
460 		goto err_nlmsg;
461 	}
462 
463 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
464 				  NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);
465 	if (ret < 0)
466 		goto err_nlmsg_tunnel;
467 
468 	l2tp_tunnel_dec_refcount(tunnel);
469 
470 	return genlmsg_unicast(net, msg, info->snd_portid);
471 
472 err_nlmsg_tunnel:
473 	l2tp_tunnel_dec_refcount(tunnel);
474 err_nlmsg:
475 	nlmsg_free(msg);
476 err:
477 	return ret;
478 }
479 
480 static int l2tp_nl_cmd_tunnel_dump(struct sk_buff *skb, struct netlink_callback *cb)
481 {
482 	int ti = cb->args[0];
483 	struct l2tp_tunnel *tunnel;
484 	struct net *net = sock_net(skb->sk);
485 
486 	for (;;) {
487 		tunnel = l2tp_tunnel_get_nth(net, ti);
488 		if (tunnel == NULL)
489 			goto out;
490 
491 		if (l2tp_nl_tunnel_send(skb, NETLINK_CB(cb->skb).portid,
492 					cb->nlh->nlmsg_seq, NLM_F_MULTI,
493 					tunnel, L2TP_CMD_TUNNEL_GET) < 0) {
494 			l2tp_tunnel_dec_refcount(tunnel);
495 			goto out;
496 		}
497 		l2tp_tunnel_dec_refcount(tunnel);
498 
499 		ti++;
500 	}
501 
502 out:
503 	cb->args[0] = ti;
504 
505 	return skb->len;
506 }
507 
508 static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *info)
509 {
510 	u32 tunnel_id = 0;
511 	u32 session_id;
512 	u32 peer_session_id;
513 	int ret = 0;
514 	struct l2tp_tunnel *tunnel;
515 	struct l2tp_session *session;
516 	struct l2tp_session_cfg cfg = { 0, };
517 	struct net *net = genl_info_net(info);
518 
519 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
520 		ret = -EINVAL;
521 		goto out;
522 	}
523 
524 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
525 	tunnel = l2tp_tunnel_get(net, tunnel_id);
526 	if (!tunnel) {
527 		ret = -ENODEV;
528 		goto out;
529 	}
530 
531 	if (!info->attrs[L2TP_ATTR_SESSION_ID]) {
532 		ret = -EINVAL;
533 		goto out_tunnel;
534 	}
535 	session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
536 
537 	if (!info->attrs[L2TP_ATTR_PEER_SESSION_ID]) {
538 		ret = -EINVAL;
539 		goto out_tunnel;
540 	}
541 	peer_session_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_SESSION_ID]);
542 
543 	if (!info->attrs[L2TP_ATTR_PW_TYPE]) {
544 		ret = -EINVAL;
545 		goto out_tunnel;
546 	}
547 	cfg.pw_type = nla_get_u16(info->attrs[L2TP_ATTR_PW_TYPE]);
548 	if (cfg.pw_type >= __L2TP_PWTYPE_MAX) {
549 		ret = -EINVAL;
550 		goto out_tunnel;
551 	}
552 
553 	/* L2TPv2 only accepts PPP pseudo-wires */
554 	if (tunnel->version == 2 && cfg.pw_type != L2TP_PWTYPE_PPP) {
555 		ret = -EPROTONOSUPPORT;
556 		goto out_tunnel;
557 	}
558 
559 	if (tunnel->version > 2) {
560 		if (info->attrs[L2TP_ATTR_L2SPEC_TYPE]) {
561 			cfg.l2specific_type = nla_get_u8(info->attrs[L2TP_ATTR_L2SPEC_TYPE]);
562 			if (cfg.l2specific_type != L2TP_L2SPECTYPE_DEFAULT &&
563 			    cfg.l2specific_type != L2TP_L2SPECTYPE_NONE) {
564 				ret = -EINVAL;
565 				goto out_tunnel;
566 			}
567 		} else {
568 			cfg.l2specific_type = L2TP_L2SPECTYPE_DEFAULT;
569 		}
570 
571 		if (info->attrs[L2TP_ATTR_COOKIE]) {
572 			u16 len = nla_len(info->attrs[L2TP_ATTR_COOKIE]);
573 			if (len > 8) {
574 				ret = -EINVAL;
575 				goto out_tunnel;
576 			}
577 			cfg.cookie_len = len;
578 			memcpy(&cfg.cookie[0], nla_data(info->attrs[L2TP_ATTR_COOKIE]), len);
579 		}
580 		if (info->attrs[L2TP_ATTR_PEER_COOKIE]) {
581 			u16 len = nla_len(info->attrs[L2TP_ATTR_PEER_COOKIE]);
582 			if (len > 8) {
583 				ret = -EINVAL;
584 				goto out_tunnel;
585 			}
586 			cfg.peer_cookie_len = len;
587 			memcpy(&cfg.peer_cookie[0], nla_data(info->attrs[L2TP_ATTR_PEER_COOKIE]), len);
588 		}
589 		if (info->attrs[L2TP_ATTR_IFNAME])
590 			cfg.ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
591 	}
592 
593 	if (info->attrs[L2TP_ATTR_DEBUG])
594 		cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
595 
596 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
597 		cfg.recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
598 
599 	if (info->attrs[L2TP_ATTR_SEND_SEQ])
600 		cfg.send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
601 
602 	if (info->attrs[L2TP_ATTR_LNS_MODE])
603 		cfg.lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
604 
605 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
606 		cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
607 
608 #ifdef CONFIG_MODULES
609 	if (l2tp_nl_cmd_ops[cfg.pw_type] == NULL) {
610 		genl_unlock();
611 		request_module("net-l2tp-type-%u", cfg.pw_type);
612 		genl_lock();
613 	}
614 #endif
615 	if ((l2tp_nl_cmd_ops[cfg.pw_type] == NULL) ||
616 	    (l2tp_nl_cmd_ops[cfg.pw_type]->session_create == NULL)) {
617 		ret = -EPROTONOSUPPORT;
618 		goto out_tunnel;
619 	}
620 
621 	ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
622 							   session_id,
623 							   peer_session_id,
624 							   &cfg);
625 
626 	if (ret >= 0) {
627 		session = l2tp_tunnel_get_session(tunnel, session_id);
628 		if (session) {
629 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
630 						  L2TP_CMD_SESSION_CREATE);
631 			l2tp_session_dec_refcount(session);
632 		}
633 	}
634 
635 out_tunnel:
636 	l2tp_tunnel_dec_refcount(tunnel);
637 out:
638 	return ret;
639 }
640 
641 static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *info)
642 {
643 	int ret = 0;
644 	struct l2tp_session *session;
645 	u16 pw_type;
646 
647 	session = l2tp_nl_session_get(info);
648 	if (session == NULL) {
649 		ret = -ENODEV;
650 		goto out;
651 	}
652 
653 	l2tp_session_notify(&l2tp_nl_family, info,
654 			    session, L2TP_CMD_SESSION_DELETE);
655 
656 	pw_type = session->pwtype;
657 	if (pw_type < __L2TP_PWTYPE_MAX)
658 		if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
659 			ret = (*l2tp_nl_cmd_ops[pw_type]->session_delete)(session);
660 
661 	l2tp_session_dec_refcount(session);
662 
663 out:
664 	return ret;
665 }
666 
667 static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *info)
668 {
669 	int ret = 0;
670 	struct l2tp_session *session;
671 
672 	session = l2tp_nl_session_get(info);
673 	if (session == NULL) {
674 		ret = -ENODEV;
675 		goto out;
676 	}
677 
678 	if (info->attrs[L2TP_ATTR_DEBUG])
679 		session->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
680 
681 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
682 		session->recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
683 
684 	if (info->attrs[L2TP_ATTR_SEND_SEQ]) {
685 		session->send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
686 		l2tp_session_set_header_len(session, session->tunnel->version);
687 	}
688 
689 	if (info->attrs[L2TP_ATTR_LNS_MODE])
690 		session->lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
691 
692 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
693 		session->reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
694 
695 	ret = l2tp_session_notify(&l2tp_nl_family, info,
696 				  session, L2TP_CMD_SESSION_MODIFY);
697 
698 	l2tp_session_dec_refcount(session);
699 
700 out:
701 	return ret;
702 }
703 
704 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
705 				struct l2tp_session *session, u8 cmd)
706 {
707 	void *hdr;
708 	struct nlattr *nest;
709 	struct l2tp_tunnel *tunnel = session->tunnel;
710 
711 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
712 	if (!hdr)
713 		return -EMSGSIZE;
714 
715 	if (nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
716 	    nla_put_u32(skb, L2TP_ATTR_SESSION_ID, session->session_id) ||
717 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
718 	    nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID,
719 			session->peer_session_id) ||
720 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, session->debug) ||
721 	    nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype))
722 		goto nla_put_failure;
723 
724 	if ((session->ifname[0] &&
725 	     nla_put_string(skb, L2TP_ATTR_IFNAME, session->ifname)) ||
726 	    (session->cookie_len &&
727 	     nla_put(skb, L2TP_ATTR_COOKIE, session->cookie_len,
728 		     &session->cookie[0])) ||
729 	    (session->peer_cookie_len &&
730 	     nla_put(skb, L2TP_ATTR_PEER_COOKIE, session->peer_cookie_len,
731 		     &session->peer_cookie[0])) ||
732 	    nla_put_u8(skb, L2TP_ATTR_RECV_SEQ, session->recv_seq) ||
733 	    nla_put_u8(skb, L2TP_ATTR_SEND_SEQ, session->send_seq) ||
734 	    nla_put_u8(skb, L2TP_ATTR_LNS_MODE, session->lns_mode) ||
735 	    (l2tp_tunnel_uses_xfrm(tunnel) &&
736 	     nla_put_u8(skb, L2TP_ATTR_USING_IPSEC, 1)) ||
737 	    (session->reorder_timeout &&
738 	     nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT,
739 			   session->reorder_timeout, L2TP_ATTR_PAD)))
740 		goto nla_put_failure;
741 
742 	nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
743 	if (nest == NULL)
744 		goto nla_put_failure;
745 
746 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
747 			      atomic_long_read(&session->stats.tx_packets),
748 			      L2TP_ATTR_STATS_PAD) ||
749 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
750 			      atomic_long_read(&session->stats.tx_bytes),
751 			      L2TP_ATTR_STATS_PAD) ||
752 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
753 			      atomic_long_read(&session->stats.tx_errors),
754 			      L2TP_ATTR_STATS_PAD) ||
755 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
756 			      atomic_long_read(&session->stats.rx_packets),
757 			      L2TP_ATTR_STATS_PAD) ||
758 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
759 			      atomic_long_read(&session->stats.rx_bytes),
760 			      L2TP_ATTR_STATS_PAD) ||
761 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
762 			      atomic_long_read(&session->stats.rx_seq_discards),
763 			      L2TP_ATTR_STATS_PAD) ||
764 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
765 			      atomic_long_read(&session->stats.rx_oos_packets),
766 			      L2TP_ATTR_STATS_PAD) ||
767 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
768 			      atomic_long_read(&session->stats.rx_errors),
769 			      L2TP_ATTR_STATS_PAD))
770 		goto nla_put_failure;
771 	nla_nest_end(skb, nest);
772 
773 	genlmsg_end(skb, hdr);
774 	return 0;
775 
776  nla_put_failure:
777 	genlmsg_cancel(skb, hdr);
778 	return -1;
779 }
780 
781 static int l2tp_nl_cmd_session_get(struct sk_buff *skb, struct genl_info *info)
782 {
783 	struct l2tp_session *session;
784 	struct sk_buff *msg;
785 	int ret;
786 
787 	session = l2tp_nl_session_get(info);
788 	if (session == NULL) {
789 		ret = -ENODEV;
790 		goto err;
791 	}
792 
793 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
794 	if (!msg) {
795 		ret = -ENOMEM;
796 		goto err_ref;
797 	}
798 
799 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
800 				   0, session, L2TP_CMD_SESSION_GET);
801 	if (ret < 0)
802 		goto err_ref_msg;
803 
804 	ret = genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
805 
806 	l2tp_session_dec_refcount(session);
807 
808 	return ret;
809 
810 err_ref_msg:
811 	nlmsg_free(msg);
812 err_ref:
813 	l2tp_session_dec_refcount(session);
814 err:
815 	return ret;
816 }
817 
818 static int l2tp_nl_cmd_session_dump(struct sk_buff *skb, struct netlink_callback *cb)
819 {
820 	struct net *net = sock_net(skb->sk);
821 	struct l2tp_session *session;
822 	struct l2tp_tunnel *tunnel = NULL;
823 	int ti = cb->args[0];
824 	int si = cb->args[1];
825 
826 	for (;;) {
827 		if (tunnel == NULL) {
828 			tunnel = l2tp_tunnel_get_nth(net, ti);
829 			if (tunnel == NULL)
830 				goto out;
831 		}
832 
833 		session = l2tp_session_get_nth(tunnel, si);
834 		if (session == NULL) {
835 			ti++;
836 			l2tp_tunnel_dec_refcount(tunnel);
837 			tunnel = NULL;
838 			si = 0;
839 			continue;
840 		}
841 
842 		if (l2tp_nl_session_send(skb, NETLINK_CB(cb->skb).portid,
843 					 cb->nlh->nlmsg_seq, NLM_F_MULTI,
844 					 session, L2TP_CMD_SESSION_GET) < 0) {
845 			l2tp_session_dec_refcount(session);
846 			l2tp_tunnel_dec_refcount(tunnel);
847 			break;
848 		}
849 		l2tp_session_dec_refcount(session);
850 
851 		si++;
852 	}
853 
854 out:
855 	cb->args[0] = ti;
856 	cb->args[1] = si;
857 
858 	return skb->len;
859 }
860 
861 static const struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
862 	[L2TP_ATTR_NONE]		= { .type = NLA_UNSPEC, },
863 	[L2TP_ATTR_PW_TYPE]		= { .type = NLA_U16, },
864 	[L2TP_ATTR_ENCAP_TYPE]		= { .type = NLA_U16, },
865 	[L2TP_ATTR_OFFSET]		= { .type = NLA_U16, },
866 	[L2TP_ATTR_DATA_SEQ]		= { .type = NLA_U8, },
867 	[L2TP_ATTR_L2SPEC_TYPE]		= { .type = NLA_U8, },
868 	[L2TP_ATTR_L2SPEC_LEN]		= { .type = NLA_U8, },
869 	[L2TP_ATTR_PROTO_VERSION]	= { .type = NLA_U8, },
870 	[L2TP_ATTR_CONN_ID]		= { .type = NLA_U32, },
871 	[L2TP_ATTR_PEER_CONN_ID]	= { .type = NLA_U32, },
872 	[L2TP_ATTR_SESSION_ID]		= { .type = NLA_U32, },
873 	[L2TP_ATTR_PEER_SESSION_ID]	= { .type = NLA_U32, },
874 	[L2TP_ATTR_UDP_CSUM]		= { .type = NLA_U8, },
875 	[L2TP_ATTR_VLAN_ID]		= { .type = NLA_U16, },
876 	[L2TP_ATTR_DEBUG]		= { .type = NLA_U32, },
877 	[L2TP_ATTR_RECV_SEQ]		= { .type = NLA_U8, },
878 	[L2TP_ATTR_SEND_SEQ]		= { .type = NLA_U8, },
879 	[L2TP_ATTR_LNS_MODE]		= { .type = NLA_U8, },
880 	[L2TP_ATTR_USING_IPSEC]		= { .type = NLA_U8, },
881 	[L2TP_ATTR_RECV_TIMEOUT]	= { .type = NLA_MSECS, },
882 	[L2TP_ATTR_FD]			= { .type = NLA_U32, },
883 	[L2TP_ATTR_IP_SADDR]		= { .type = NLA_U32, },
884 	[L2TP_ATTR_IP_DADDR]		= { .type = NLA_U32, },
885 	[L2TP_ATTR_UDP_SPORT]		= { .type = NLA_U16, },
886 	[L2TP_ATTR_UDP_DPORT]		= { .type = NLA_U16, },
887 	[L2TP_ATTR_MTU]			= { .type = NLA_U16, },
888 	[L2TP_ATTR_MRU]			= { .type = NLA_U16, },
889 	[L2TP_ATTR_STATS]		= { .type = NLA_NESTED, },
890 	[L2TP_ATTR_IP6_SADDR] = {
891 		.type = NLA_BINARY,
892 		.len = sizeof(struct in6_addr),
893 	},
894 	[L2TP_ATTR_IP6_DADDR] = {
895 		.type = NLA_BINARY,
896 		.len = sizeof(struct in6_addr),
897 	},
898 	[L2TP_ATTR_IFNAME] = {
899 		.type = NLA_NUL_STRING,
900 		.len = IFNAMSIZ - 1,
901 	},
902 	[L2TP_ATTR_COOKIE] = {
903 		.type = NLA_BINARY,
904 		.len = 8,
905 	},
906 	[L2TP_ATTR_PEER_COOKIE] = {
907 		.type = NLA_BINARY,
908 		.len = 8,
909 	},
910 };
911 
912 static const struct genl_ops l2tp_nl_ops[] = {
913 	{
914 		.cmd = L2TP_CMD_NOOP,
915 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
916 		.doit = l2tp_nl_cmd_noop,
917 		/* can be retrieved by unprivileged users */
918 	},
919 	{
920 		.cmd = L2TP_CMD_TUNNEL_CREATE,
921 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
922 		.doit = l2tp_nl_cmd_tunnel_create,
923 		.flags = GENL_UNS_ADMIN_PERM,
924 	},
925 	{
926 		.cmd = L2TP_CMD_TUNNEL_DELETE,
927 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
928 		.doit = l2tp_nl_cmd_tunnel_delete,
929 		.flags = GENL_UNS_ADMIN_PERM,
930 	},
931 	{
932 		.cmd = L2TP_CMD_TUNNEL_MODIFY,
933 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
934 		.doit = l2tp_nl_cmd_tunnel_modify,
935 		.flags = GENL_UNS_ADMIN_PERM,
936 	},
937 	{
938 		.cmd = L2TP_CMD_TUNNEL_GET,
939 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
940 		.doit = l2tp_nl_cmd_tunnel_get,
941 		.dumpit = l2tp_nl_cmd_tunnel_dump,
942 		.flags = GENL_UNS_ADMIN_PERM,
943 	},
944 	{
945 		.cmd = L2TP_CMD_SESSION_CREATE,
946 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
947 		.doit = l2tp_nl_cmd_session_create,
948 		.flags = GENL_UNS_ADMIN_PERM,
949 	},
950 	{
951 		.cmd = L2TP_CMD_SESSION_DELETE,
952 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
953 		.doit = l2tp_nl_cmd_session_delete,
954 		.flags = GENL_UNS_ADMIN_PERM,
955 	},
956 	{
957 		.cmd = L2TP_CMD_SESSION_MODIFY,
958 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
959 		.doit = l2tp_nl_cmd_session_modify,
960 		.flags = GENL_UNS_ADMIN_PERM,
961 	},
962 	{
963 		.cmd = L2TP_CMD_SESSION_GET,
964 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
965 		.doit = l2tp_nl_cmd_session_get,
966 		.dumpit = l2tp_nl_cmd_session_dump,
967 		.flags = GENL_UNS_ADMIN_PERM,
968 	},
969 };
970 
971 static struct genl_family l2tp_nl_family __ro_after_init = {
972 	.name		= L2TP_GENL_NAME,
973 	.version	= L2TP_GENL_VERSION,
974 	.hdrsize	= 0,
975 	.maxattr	= L2TP_ATTR_MAX,
976 	.policy = l2tp_nl_policy,
977 	.netnsok	= true,
978 	.module		= THIS_MODULE,
979 	.ops		= l2tp_nl_ops,
980 	.n_ops		= ARRAY_SIZE(l2tp_nl_ops),
981 	.mcgrps		= l2tp_multicast_group,
982 	.n_mcgrps	= ARRAY_SIZE(l2tp_multicast_group),
983 };
984 
985 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops)
986 {
987 	int ret;
988 
989 	ret = -EINVAL;
990 	if (pw_type >= __L2TP_PWTYPE_MAX)
991 		goto err;
992 
993 	genl_lock();
994 	ret = -EBUSY;
995 	if (l2tp_nl_cmd_ops[pw_type])
996 		goto out;
997 
998 	l2tp_nl_cmd_ops[pw_type] = ops;
999 	ret = 0;
1000 
1001 out:
1002 	genl_unlock();
1003 err:
1004 	return ret;
1005 }
1006 EXPORT_SYMBOL_GPL(l2tp_nl_register_ops);
1007 
1008 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type)
1009 {
1010 	if (pw_type < __L2TP_PWTYPE_MAX) {
1011 		genl_lock();
1012 		l2tp_nl_cmd_ops[pw_type] = NULL;
1013 		genl_unlock();
1014 	}
1015 }
1016 EXPORT_SYMBOL_GPL(l2tp_nl_unregister_ops);
1017 
1018 static int __init l2tp_nl_init(void)
1019 {
1020 	pr_info("L2TP netlink interface\n");
1021 	return genl_register_family(&l2tp_nl_family);
1022 }
1023 
1024 static void l2tp_nl_cleanup(void)
1025 {
1026 	genl_unregister_family(&l2tp_nl_family);
1027 }
1028 
1029 module_init(l2tp_nl_init);
1030 module_exit(l2tp_nl_cleanup);
1031 
1032 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1033 MODULE_DESCRIPTION("L2TP netlink");
1034 MODULE_LICENSE("GPL");
1035 MODULE_VERSION("1.0");
1036 MODULE_ALIAS_GENL_FAMILY("l2tp");
1037