xref: /openbmc/linux/net/l2tp/l2tp_netlink.c (revision b71a61ccfebb4ff733d2d9fc66cd5c75b7ae46a2) 
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 static struct genl_family l2tp_nl_family;
31 
32 static const struct genl_multicast_group l2tp_multicast_group[] = {
33 	{
34 		.name = L2TP_GENL_MCGROUP,
35 	},
36 };
37 
38 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq,
39 			       int flags, struct l2tp_tunnel *tunnel, u8 cmd);
40 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq,
41 				int flags, struct l2tp_session *session,
42 				u8 cmd);
43 
44 /* Accessed under genl lock */
45 static const struct l2tp_nl_cmd_ops *l2tp_nl_cmd_ops[__L2TP_PWTYPE_MAX];
46 
47 static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
48 {
49 	u32 tunnel_id;
50 	u32 session_id;
51 	char *ifname;
52 	struct l2tp_tunnel *tunnel;
53 	struct l2tp_session *session = NULL;
54 	struct net *net = genl_info_net(info);
55 
56 	if (info->attrs[L2TP_ATTR_IFNAME]) {
57 		ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
58 		session = l2tp_session_get_by_ifname(net, ifname);
59 	} else if ((info->attrs[L2TP_ATTR_SESSION_ID]) &&
60 		   (info->attrs[L2TP_ATTR_CONN_ID])) {
61 		tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
62 		session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
63 		tunnel = l2tp_tunnel_get(net, tunnel_id);
64 		if (tunnel) {
65 			session = l2tp_tunnel_get_session(tunnel, session_id);
66 			l2tp_tunnel_dec_refcount(tunnel);
67 		}
68 	}
69 
70 	return session;
71 }
72 
73 static int l2tp_nl_cmd_noop(struct sk_buff *skb, struct genl_info *info)
74 {
75 	struct sk_buff *msg;
76 	void *hdr;
77 	int ret = -ENOBUFS;
78 
79 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
80 	if (!msg) {
81 		ret = -ENOMEM;
82 		goto out;
83 	}
84 
85 	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
86 			  &l2tp_nl_family, 0, L2TP_CMD_NOOP);
87 	if (!hdr) {
88 		ret = -EMSGSIZE;
89 		goto err_out;
90 	}
91 
92 	genlmsg_end(msg, hdr);
93 
94 	return genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
95 
96 err_out:
97 	nlmsg_free(msg);
98 
99 out:
100 	return ret;
101 }
102 
103 static int l2tp_tunnel_notify(struct genl_family *family,
104 			      struct genl_info *info,
105 			      struct l2tp_tunnel *tunnel,
106 			      u8 cmd)
107 {
108 	struct sk_buff *msg;
109 	int ret;
110 
111 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
112 	if (!msg)
113 		return -ENOMEM;
114 
115 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
116 				  NLM_F_ACK, tunnel, cmd);
117 
118 	if (ret >= 0) {
119 		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
120 		/* We don't care if no one is listening */
121 		if (ret == -ESRCH)
122 			ret = 0;
123 		return ret;
124 	}
125 
126 	nlmsg_free(msg);
127 
128 	return ret;
129 }
130 
131 static int l2tp_session_notify(struct genl_family *family,
132 			       struct genl_info *info,
133 			       struct l2tp_session *session,
134 			       u8 cmd)
135 {
136 	struct sk_buff *msg;
137 	int ret;
138 
139 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
140 	if (!msg)
141 		return -ENOMEM;
142 
143 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
144 				   NLM_F_ACK, session, cmd);
145 
146 	if (ret >= 0) {
147 		ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
148 		/* We don't care if no one is listening */
149 		if (ret == -ESRCH)
150 			ret = 0;
151 		return ret;
152 	}
153 
154 	nlmsg_free(msg);
155 
156 	return ret;
157 }
158 
159 static int l2tp_nl_cmd_tunnel_create(struct sk_buff *skb, struct genl_info *info)
160 {
161 	u32 tunnel_id;
162 	u32 peer_tunnel_id;
163 	int proto_version;
164 	int fd;
165 	int ret = 0;
166 	struct l2tp_tunnel_cfg cfg = { 0, };
167 	struct l2tp_tunnel *tunnel;
168 	struct net *net = genl_info_net(info);
169 
170 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
171 		ret = -EINVAL;
172 		goto out;
173 	}
174 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
175 
176 	if (!info->attrs[L2TP_ATTR_PEER_CONN_ID]) {
177 		ret = -EINVAL;
178 		goto out;
179 	}
180 	peer_tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_CONN_ID]);
181 
182 	if (!info->attrs[L2TP_ATTR_PROTO_VERSION]) {
183 		ret = -EINVAL;
184 		goto out;
185 	}
186 	proto_version = nla_get_u8(info->attrs[L2TP_ATTR_PROTO_VERSION]);
187 
188 	if (!info->attrs[L2TP_ATTR_ENCAP_TYPE]) {
189 		ret = -EINVAL;
190 		goto out;
191 	}
192 	cfg.encap = nla_get_u16(info->attrs[L2TP_ATTR_ENCAP_TYPE]);
193 
194 	fd = -1;
195 	if (info->attrs[L2TP_ATTR_FD]) {
196 		fd = nla_get_u32(info->attrs[L2TP_ATTR_FD]);
197 	} else {
198 #if IS_ENABLED(CONFIG_IPV6)
199 		if (info->attrs[L2TP_ATTR_IP6_SADDR] &&
200 		    info->attrs[L2TP_ATTR_IP6_DADDR]) {
201 			cfg.local_ip6 = nla_data(
202 				info->attrs[L2TP_ATTR_IP6_SADDR]);
203 			cfg.peer_ip6 = nla_data(
204 				info->attrs[L2TP_ATTR_IP6_DADDR]);
205 		} else
206 #endif
207 		if (info->attrs[L2TP_ATTR_IP_SADDR] &&
208 		    info->attrs[L2TP_ATTR_IP_DADDR]) {
209 			cfg.local_ip.s_addr = nla_get_in_addr(
210 				info->attrs[L2TP_ATTR_IP_SADDR]);
211 			cfg.peer_ip.s_addr = nla_get_in_addr(
212 				info->attrs[L2TP_ATTR_IP_DADDR]);
213 		} else {
214 			ret = -EINVAL;
215 			goto out;
216 		}
217 		if (info->attrs[L2TP_ATTR_UDP_SPORT])
218 			cfg.local_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_SPORT]);
219 		if (info->attrs[L2TP_ATTR_UDP_DPORT])
220 			cfg.peer_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_DPORT]);
221 		cfg.use_udp_checksums = nla_get_flag(
222 			info->attrs[L2TP_ATTR_UDP_CSUM]);
223 
224 #if IS_ENABLED(CONFIG_IPV6)
225 		cfg.udp6_zero_tx_checksums = nla_get_flag(
226 			info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_TX]);
227 		cfg.udp6_zero_rx_checksums = nla_get_flag(
228 			info->attrs[L2TP_ATTR_UDP_ZERO_CSUM6_RX]);
229 #endif
230 	}
231 
232 	if (info->attrs[L2TP_ATTR_DEBUG])
233 		cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
234 
235 	ret = -EINVAL;
236 	switch (cfg.encap) {
237 	case L2TP_ENCAPTYPE_UDP:
238 	case L2TP_ENCAPTYPE_IP:
239 		ret = l2tp_tunnel_create(net, fd, proto_version, tunnel_id,
240 					 peer_tunnel_id, &cfg, &tunnel);
241 		break;
242 	}
243 
244 	if (ret < 0)
245 		goto out;
246 
247 	l2tp_tunnel_inc_refcount(tunnel);
248 	ret = l2tp_tunnel_register(tunnel, net, &cfg);
249 	if (ret < 0) {
250 		kfree(tunnel);
251 		goto out;
252 	}
253 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info, tunnel,
254 				 L2TP_CMD_TUNNEL_CREATE);
255 	l2tp_tunnel_dec_refcount(tunnel);
256 
257 out:
258 	return ret;
259 }
260 
261 static int l2tp_nl_cmd_tunnel_delete(struct sk_buff *skb, struct genl_info *info)
262 {
263 	struct l2tp_tunnel *tunnel;
264 	u32 tunnel_id;
265 	int ret = 0;
266 	struct net *net = genl_info_net(info);
267 
268 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
269 		ret = -EINVAL;
270 		goto out;
271 	}
272 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
273 
274 	tunnel = l2tp_tunnel_get(net, tunnel_id);
275 	if (!tunnel) {
276 		ret = -ENODEV;
277 		goto out;
278 	}
279 
280 	l2tp_tunnel_notify(&l2tp_nl_family, info,
281 			   tunnel, L2TP_CMD_TUNNEL_DELETE);
282 
283 	l2tp_tunnel_delete(tunnel);
284 
285 	l2tp_tunnel_dec_refcount(tunnel);
286 
287 out:
288 	return ret;
289 }
290 
291 static int l2tp_nl_cmd_tunnel_modify(struct sk_buff *skb, struct genl_info *info)
292 {
293 	struct l2tp_tunnel *tunnel;
294 	u32 tunnel_id;
295 	int ret = 0;
296 	struct net *net = genl_info_net(info);
297 
298 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
299 		ret = -EINVAL;
300 		goto out;
301 	}
302 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
303 
304 	tunnel = l2tp_tunnel_get(net, tunnel_id);
305 	if (!tunnel) {
306 		ret = -ENODEV;
307 		goto out;
308 	}
309 
310 	if (info->attrs[L2TP_ATTR_DEBUG])
311 		tunnel->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
312 
313 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info,
314 				 tunnel, L2TP_CMD_TUNNEL_MODIFY);
315 
316 	l2tp_tunnel_dec_refcount(tunnel);
317 
318 out:
319 	return ret;
320 }
321 
322 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
323 			       struct l2tp_tunnel *tunnel, u8 cmd)
324 {
325 	void *hdr;
326 	struct nlattr *nest;
327 	struct sock *sk = NULL;
328 	struct inet_sock *inet;
329 #if IS_ENABLED(CONFIG_IPV6)
330 	struct ipv6_pinfo *np = NULL;
331 #endif
332 
333 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
334 	if (!hdr)
335 		return -EMSGSIZE;
336 
337 	if (nla_put_u8(skb, L2TP_ATTR_PROTO_VERSION, tunnel->version) ||
338 	    nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
339 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
340 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, tunnel->debug) ||
341 	    nla_put_u16(skb, L2TP_ATTR_ENCAP_TYPE, tunnel->encap))
342 		goto nla_put_failure;
343 
344 	nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
345 	if (nest == NULL)
346 		goto nla_put_failure;
347 
348 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
349 			      atomic_long_read(&tunnel->stats.tx_packets),
350 			      L2TP_ATTR_STATS_PAD) ||
351 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
352 			      atomic_long_read(&tunnel->stats.tx_bytes),
353 			      L2TP_ATTR_STATS_PAD) ||
354 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
355 			      atomic_long_read(&tunnel->stats.tx_errors),
356 			      L2TP_ATTR_STATS_PAD) ||
357 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
358 			      atomic_long_read(&tunnel->stats.rx_packets),
359 			      L2TP_ATTR_STATS_PAD) ||
360 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
361 			      atomic_long_read(&tunnel->stats.rx_bytes),
362 			      L2TP_ATTR_STATS_PAD) ||
363 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
364 			      atomic_long_read(&tunnel->stats.rx_seq_discards),
365 			      L2TP_ATTR_STATS_PAD) ||
366 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
367 			      atomic_long_read(&tunnel->stats.rx_oos_packets),
368 			      L2TP_ATTR_STATS_PAD) ||
369 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
370 			      atomic_long_read(&tunnel->stats.rx_errors),
371 			      L2TP_ATTR_STATS_PAD))
372 		goto nla_put_failure;
373 	nla_nest_end(skb, nest);
374 
375 	sk = tunnel->sock;
376 	if (!sk)
377 		goto out;
378 
379 #if IS_ENABLED(CONFIG_IPV6)
380 	if (sk->sk_family == AF_INET6)
381 		np = inet6_sk(sk);
382 #endif
383 
384 	inet = inet_sk(sk);
385 
386 	switch (tunnel->encap) {
387 	case L2TP_ENCAPTYPE_UDP:
388 		switch (sk->sk_family) {
389 		case AF_INET:
390 			if (nla_put_u8(skb, L2TP_ATTR_UDP_CSUM, !sk->sk_no_check_tx))
391 				goto nla_put_failure;
392 			break;
393 #if IS_ENABLED(CONFIG_IPV6)
394 		case AF_INET6:
395 			if (udp_get_no_check6_tx(sk) &&
396 			    nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_TX))
397 				goto nla_put_failure;
398 			if (udp_get_no_check6_rx(sk) &&
399 			    nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_RX))
400 				goto nla_put_failure;
401 			break;
402 #endif
403 		}
404 		if (nla_put_u16(skb, L2TP_ATTR_UDP_SPORT, ntohs(inet->inet_sport)) ||
405 		    nla_put_u16(skb, L2TP_ATTR_UDP_DPORT, ntohs(inet->inet_dport)))
406 			goto nla_put_failure;
407 		/* fall through  */
408 	case L2TP_ENCAPTYPE_IP:
409 #if IS_ENABLED(CONFIG_IPV6)
410 		if (np) {
411 			if (nla_put_in6_addr(skb, L2TP_ATTR_IP6_SADDR,
412 					     &np->saddr) ||
413 			    nla_put_in6_addr(skb, L2TP_ATTR_IP6_DADDR,
414 					     &sk->sk_v6_daddr))
415 				goto nla_put_failure;
416 		} else
417 #endif
418 		if (nla_put_in_addr(skb, L2TP_ATTR_IP_SADDR,
419 				    inet->inet_saddr) ||
420 		    nla_put_in_addr(skb, L2TP_ATTR_IP_DADDR,
421 				    inet->inet_daddr))
422 			goto nla_put_failure;
423 		break;
424 	}
425 
426 out:
427 	genlmsg_end(skb, hdr);
428 	return 0;
429 
430 nla_put_failure:
431 	genlmsg_cancel(skb, hdr);
432 	return -1;
433 }
434 
435 static int l2tp_nl_cmd_tunnel_get(struct sk_buff *skb, struct genl_info *info)
436 {
437 	struct l2tp_tunnel *tunnel;
438 	struct sk_buff *msg;
439 	u32 tunnel_id;
440 	int ret = -ENOBUFS;
441 	struct net *net = genl_info_net(info);
442 
443 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
444 		ret = -EINVAL;
445 		goto err;
446 	}
447 
448 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
449 
450 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
451 	if (!msg) {
452 		ret = -ENOMEM;
453 		goto err;
454 	}
455 
456 	tunnel = l2tp_tunnel_get(net, tunnel_id);
457 	if (!tunnel) {
458 		ret = -ENODEV;
459 		goto err_nlmsg;
460 	}
461 
462 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
463 				  NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);
464 	if (ret < 0)
465 		goto err_nlmsg_tunnel;
466 
467 	l2tp_tunnel_dec_refcount(tunnel);
468 
469 	return genlmsg_unicast(net, msg, info->snd_portid);
470 
471 err_nlmsg_tunnel:
472 	l2tp_tunnel_dec_refcount(tunnel);
473 err_nlmsg:
474 	nlmsg_free(msg);
475 err:
476 	return ret;
477 }
478 
479 static int l2tp_nl_cmd_tunnel_dump(struct sk_buff *skb, struct netlink_callback *cb)
480 {
481 	int ti = cb->args[0];
482 	struct l2tp_tunnel *tunnel;
483 	struct net *net = sock_net(skb->sk);
484 
485 	for (;;) {
486 		tunnel = l2tp_tunnel_get_nth(net, ti);
487 		if (tunnel == NULL)
488 			goto out;
489 
490 		if (l2tp_nl_tunnel_send(skb, NETLINK_CB(cb->skb).portid,
491 					cb->nlh->nlmsg_seq, NLM_F_MULTI,
492 					tunnel, L2TP_CMD_TUNNEL_GET) < 0) {
493 			l2tp_tunnel_dec_refcount(tunnel);
494 			goto out;
495 		}
496 		l2tp_tunnel_dec_refcount(tunnel);
497 
498 		ti++;
499 	}
500 
501 out:
502 	cb->args[0] = ti;
503 
504 	return skb->len;
505 }
506 
507 static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *info)
508 {
509 	u32 tunnel_id = 0;
510 	u32 session_id;
511 	u32 peer_session_id;
512 	int ret = 0;
513 	struct l2tp_tunnel *tunnel;
514 	struct l2tp_session *session;
515 	struct l2tp_session_cfg cfg = { 0, };
516 	struct net *net = genl_info_net(info);
517 
518 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
519 		ret = -EINVAL;
520 		goto out;
521 	}
522 
523 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
524 	tunnel = l2tp_tunnel_get(net, tunnel_id);
525 	if (!tunnel) {
526 		ret = -ENODEV;
527 		goto out;
528 	}
529 
530 	if (!info->attrs[L2TP_ATTR_SESSION_ID]) {
531 		ret = -EINVAL;
532 		goto out_tunnel;
533 	}
534 	session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
535 
536 	if (!info->attrs[L2TP_ATTR_PEER_SESSION_ID]) {
537 		ret = -EINVAL;
538 		goto out_tunnel;
539 	}
540 	peer_session_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_SESSION_ID]);
541 
542 	if (!info->attrs[L2TP_ATTR_PW_TYPE]) {
543 		ret = -EINVAL;
544 		goto out_tunnel;
545 	}
546 	cfg.pw_type = nla_get_u16(info->attrs[L2TP_ATTR_PW_TYPE]);
547 	if (cfg.pw_type >= __L2TP_PWTYPE_MAX) {
548 		ret = -EINVAL;
549 		goto out_tunnel;
550 	}
551 
552 	/* L2TPv2 only accepts PPP pseudo-wires */
553 	if (tunnel->version == 2 && cfg.pw_type != L2TP_PWTYPE_PPP) {
554 		ret = -EPROTONOSUPPORT;
555 		goto out_tunnel;
556 	}
557 
558 	if (tunnel->version > 2) {
559 		if (info->attrs[L2TP_ATTR_L2SPEC_TYPE]) {
560 			cfg.l2specific_type = nla_get_u8(info->attrs[L2TP_ATTR_L2SPEC_TYPE]);
561 			if (cfg.l2specific_type != L2TP_L2SPECTYPE_DEFAULT &&
562 			    cfg.l2specific_type != L2TP_L2SPECTYPE_NONE) {
563 				ret = -EINVAL;
564 				goto out_tunnel;
565 			}
566 		} else {
567 			cfg.l2specific_type = L2TP_L2SPECTYPE_DEFAULT;
568 		}
569 
570 		if (info->attrs[L2TP_ATTR_COOKIE]) {
571 			u16 len = nla_len(info->attrs[L2TP_ATTR_COOKIE]);
572 
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 
583 			if (len > 8) {
584 				ret = -EINVAL;
585 				goto out_tunnel;
586 			}
587 			cfg.peer_cookie_len = len;
588 			memcpy(&cfg.peer_cookie[0], nla_data(info->attrs[L2TP_ATTR_PEER_COOKIE]), len);
589 		}
590 		if (info->attrs[L2TP_ATTR_IFNAME])
591 			cfg.ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
592 	}
593 
594 	if (info->attrs[L2TP_ATTR_DEBUG])
595 		cfg.debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
596 
597 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
598 		cfg.recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
599 
600 	if (info->attrs[L2TP_ATTR_SEND_SEQ])
601 		cfg.send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
602 
603 	if (info->attrs[L2TP_ATTR_LNS_MODE])
604 		cfg.lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
605 
606 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
607 		cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
608 
609 #ifdef CONFIG_MODULES
610 	if (l2tp_nl_cmd_ops[cfg.pw_type] == NULL) {
611 		genl_unlock();
612 		request_module("net-l2tp-type-%u", cfg.pw_type);
613 		genl_lock();
614 	}
615 #endif
616 	if ((l2tp_nl_cmd_ops[cfg.pw_type] == NULL) ||
617 	    (l2tp_nl_cmd_ops[cfg.pw_type]->session_create == NULL)) {
618 		ret = -EPROTONOSUPPORT;
619 		goto out_tunnel;
620 	}
621 
622 	ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
623 							   session_id,
624 							   peer_session_id,
625 							   &cfg);
626 
627 	if (ret >= 0) {
628 		session = l2tp_tunnel_get_session(tunnel, session_id);
629 		if (session) {
630 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
631 						  L2TP_CMD_SESSION_CREATE);
632 			l2tp_session_dec_refcount(session);
633 		}
634 	}
635 
636 out_tunnel:
637 	l2tp_tunnel_dec_refcount(tunnel);
638 out:
639 	return ret;
640 }
641 
642 static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *info)
643 {
644 	int ret = 0;
645 	struct l2tp_session *session;
646 	u16 pw_type;
647 
648 	session = l2tp_nl_session_get(info);
649 	if (session == NULL) {
650 		ret = -ENODEV;
651 		goto out;
652 	}
653 
654 	l2tp_session_notify(&l2tp_nl_family, info,
655 			    session, L2TP_CMD_SESSION_DELETE);
656 
657 	pw_type = session->pwtype;
658 	if (pw_type < __L2TP_PWTYPE_MAX)
659 		if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
660 			ret = (*l2tp_nl_cmd_ops[pw_type]->session_delete)(session);
661 
662 	l2tp_session_dec_refcount(session);
663 
664 out:
665 	return ret;
666 }
667 
668 static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *info)
669 {
670 	int ret = 0;
671 	struct l2tp_session *session;
672 
673 	session = l2tp_nl_session_get(info);
674 	if (session == NULL) {
675 		ret = -ENODEV;
676 		goto out;
677 	}
678 
679 	if (info->attrs[L2TP_ATTR_DEBUG])
680 		session->debug = nla_get_u32(info->attrs[L2TP_ATTR_DEBUG]);
681 
682 	if (info->attrs[L2TP_ATTR_RECV_SEQ])
683 		session->recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
684 
685 	if (info->attrs[L2TP_ATTR_SEND_SEQ]) {
686 		session->send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
687 		l2tp_session_set_header_len(session, session->tunnel->version);
688 	}
689 
690 	if (info->attrs[L2TP_ATTR_LNS_MODE])
691 		session->lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
692 
693 	if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
694 		session->reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
695 
696 	ret = l2tp_session_notify(&l2tp_nl_family, info,
697 				  session, L2TP_CMD_SESSION_MODIFY);
698 
699 	l2tp_session_dec_refcount(session);
700 
701 out:
702 	return ret;
703 }
704 
705 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
706 				struct l2tp_session *session, u8 cmd)
707 {
708 	void *hdr;
709 	struct nlattr *nest;
710 	struct l2tp_tunnel *tunnel = session->tunnel;
711 
712 	hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
713 	if (!hdr)
714 		return -EMSGSIZE;
715 
716 	if (nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
717 	    nla_put_u32(skb, L2TP_ATTR_SESSION_ID, session->session_id) ||
718 	    nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
719 	    nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID,
720 			session->peer_session_id) ||
721 	    nla_put_u32(skb, L2TP_ATTR_DEBUG, session->debug) ||
722 	    nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype))
723 		goto nla_put_failure;
724 
725 	if ((session->ifname[0] &&
726 	     nla_put_string(skb, L2TP_ATTR_IFNAME, session->ifname)) ||
727 	    (session->cookie_len &&
728 	     nla_put(skb, L2TP_ATTR_COOKIE, session->cookie_len,
729 		     &session->cookie[0])) ||
730 	    (session->peer_cookie_len &&
731 	     nla_put(skb, L2TP_ATTR_PEER_COOKIE, session->peer_cookie_len,
732 		     &session->peer_cookie[0])) ||
733 	    nla_put_u8(skb, L2TP_ATTR_RECV_SEQ, session->recv_seq) ||
734 	    nla_put_u8(skb, L2TP_ATTR_SEND_SEQ, session->send_seq) ||
735 	    nla_put_u8(skb, L2TP_ATTR_LNS_MODE, session->lns_mode) ||
736 	    (l2tp_tunnel_uses_xfrm(tunnel) &&
737 	     nla_put_u8(skb, L2TP_ATTR_USING_IPSEC, 1)) ||
738 	    (session->reorder_timeout &&
739 	     nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT,
740 			   session->reorder_timeout, L2TP_ATTR_PAD)))
741 		goto nla_put_failure;
742 
743 	nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
744 	if (nest == NULL)
745 		goto nla_put_failure;
746 
747 	if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
748 			      atomic_long_read(&session->stats.tx_packets),
749 			      L2TP_ATTR_STATS_PAD) ||
750 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
751 			      atomic_long_read(&session->stats.tx_bytes),
752 			      L2TP_ATTR_STATS_PAD) ||
753 	    nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
754 			      atomic_long_read(&session->stats.tx_errors),
755 			      L2TP_ATTR_STATS_PAD) ||
756 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
757 			      atomic_long_read(&session->stats.rx_packets),
758 			      L2TP_ATTR_STATS_PAD) ||
759 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
760 			      atomic_long_read(&session->stats.rx_bytes),
761 			      L2TP_ATTR_STATS_PAD) ||
762 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
763 			      atomic_long_read(&session->stats.rx_seq_discards),
764 			      L2TP_ATTR_STATS_PAD) ||
765 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
766 			      atomic_long_read(&session->stats.rx_oos_packets),
767 			      L2TP_ATTR_STATS_PAD) ||
768 	    nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
769 			      atomic_long_read(&session->stats.rx_errors),
770 			      L2TP_ATTR_STATS_PAD))
771 		goto nla_put_failure;
772 	nla_nest_end(skb, nest);
773 
774 	genlmsg_end(skb, hdr);
775 	return 0;
776 
777  nla_put_failure:
778 	genlmsg_cancel(skb, hdr);
779 	return -1;
780 }
781 
782 static int l2tp_nl_cmd_session_get(struct sk_buff *skb, struct genl_info *info)
783 {
784 	struct l2tp_session *session;
785 	struct sk_buff *msg;
786 	int ret;
787 
788 	session = l2tp_nl_session_get(info);
789 	if (session == NULL) {
790 		ret = -ENODEV;
791 		goto err;
792 	}
793 
794 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
795 	if (!msg) {
796 		ret = -ENOMEM;
797 		goto err_ref;
798 	}
799 
800 	ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
801 				   0, session, L2TP_CMD_SESSION_GET);
802 	if (ret < 0)
803 		goto err_ref_msg;
804 
805 	ret = genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
806 
807 	l2tp_session_dec_refcount(session);
808 
809 	return ret;
810 
811 err_ref_msg:
812 	nlmsg_free(msg);
813 err_ref:
814 	l2tp_session_dec_refcount(session);
815 err:
816 	return ret;
817 }
818 
819 static int l2tp_nl_cmd_session_dump(struct sk_buff *skb, struct netlink_callback *cb)
820 {
821 	struct net *net = sock_net(skb->sk);
822 	struct l2tp_session *session;
823 	struct l2tp_tunnel *tunnel = NULL;
824 	int ti = cb->args[0];
825 	int si = cb->args[1];
826 
827 	for (;;) {
828 		if (tunnel == NULL) {
829 			tunnel = l2tp_tunnel_get_nth(net, ti);
830 			if (tunnel == NULL)
831 				goto out;
832 		}
833 
834 		session = l2tp_session_get_nth(tunnel, si);
835 		if (session == NULL) {
836 			ti++;
837 			l2tp_tunnel_dec_refcount(tunnel);
838 			tunnel = NULL;
839 			si = 0;
840 			continue;
841 		}
842 
843 		if (l2tp_nl_session_send(skb, NETLINK_CB(cb->skb).portid,
844 					 cb->nlh->nlmsg_seq, NLM_F_MULTI,
845 					 session, L2TP_CMD_SESSION_GET) < 0) {
846 			l2tp_session_dec_refcount(session);
847 			l2tp_tunnel_dec_refcount(tunnel);
848 			break;
849 		}
850 		l2tp_session_dec_refcount(session);
851 
852 		si++;
853 	}
854 
855 out:
856 	cb->args[0] = ti;
857 	cb->args[1] = si;
858 
859 	return skb->len;
860 }
861 
862 static const struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
863 	[L2TP_ATTR_NONE]		= { .type = NLA_UNSPEC, },
864 	[L2TP_ATTR_PW_TYPE]		= { .type = NLA_U16, },
865 	[L2TP_ATTR_ENCAP_TYPE]		= { .type = NLA_U16, },
866 	[L2TP_ATTR_OFFSET]		= { .type = NLA_U16, },
867 	[L2TP_ATTR_DATA_SEQ]		= { .type = NLA_U8, },
868 	[L2TP_ATTR_L2SPEC_TYPE]		= { .type = NLA_U8, },
869 	[L2TP_ATTR_L2SPEC_LEN]		= { .type = NLA_U8, },
870 	[L2TP_ATTR_PROTO_VERSION]	= { .type = NLA_U8, },
871 	[L2TP_ATTR_CONN_ID]		= { .type = NLA_U32, },
872 	[L2TP_ATTR_PEER_CONN_ID]	= { .type = NLA_U32, },
873 	[L2TP_ATTR_SESSION_ID]		= { .type = NLA_U32, },
874 	[L2TP_ATTR_PEER_SESSION_ID]	= { .type = NLA_U32, },
875 	[L2TP_ATTR_UDP_CSUM]		= { .type = NLA_U8, },
876 	[L2TP_ATTR_VLAN_ID]		= { .type = NLA_U16, },
877 	[L2TP_ATTR_DEBUG]		= { .type = NLA_U32, },
878 	[L2TP_ATTR_RECV_SEQ]		= { .type = NLA_U8, },
879 	[L2TP_ATTR_SEND_SEQ]		= { .type = NLA_U8, },
880 	[L2TP_ATTR_LNS_MODE]		= { .type = NLA_U8, },
881 	[L2TP_ATTR_USING_IPSEC]		= { .type = NLA_U8, },
882 	[L2TP_ATTR_RECV_TIMEOUT]	= { .type = NLA_MSECS, },
883 	[L2TP_ATTR_FD]			= { .type = NLA_U32, },
884 	[L2TP_ATTR_IP_SADDR]		= { .type = NLA_U32, },
885 	[L2TP_ATTR_IP_DADDR]		= { .type = NLA_U32, },
886 	[L2TP_ATTR_UDP_SPORT]		= { .type = NLA_U16, },
887 	[L2TP_ATTR_UDP_DPORT]		= { .type = NLA_U16, },
888 	[L2TP_ATTR_MTU]			= { .type = NLA_U16, },
889 	[L2TP_ATTR_MRU]			= { .type = NLA_U16, },
890 	[L2TP_ATTR_STATS]		= { .type = NLA_NESTED, },
891 	[L2TP_ATTR_IP6_SADDR] = {
892 		.type = NLA_BINARY,
893 		.len = sizeof(struct in6_addr),
894 	},
895 	[L2TP_ATTR_IP6_DADDR] = {
896 		.type = NLA_BINARY,
897 		.len = sizeof(struct in6_addr),
898 	},
899 	[L2TP_ATTR_IFNAME] = {
900 		.type = NLA_NUL_STRING,
901 		.len = IFNAMSIZ - 1,
902 	},
903 	[L2TP_ATTR_COOKIE] = {
904 		.type = NLA_BINARY,
905 		.len = 8,
906 	},
907 	[L2TP_ATTR_PEER_COOKIE] = {
908 		.type = NLA_BINARY,
909 		.len = 8,
910 	},
911 };
912 
913 static const struct genl_ops l2tp_nl_ops[] = {
914 	{
915 		.cmd = L2TP_CMD_NOOP,
916 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
917 		.doit = l2tp_nl_cmd_noop,
918 		/* can be retrieved by unprivileged users */
919 	},
920 	{
921 		.cmd = L2TP_CMD_TUNNEL_CREATE,
922 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
923 		.doit = l2tp_nl_cmd_tunnel_create,
924 		.flags = GENL_UNS_ADMIN_PERM,
925 	},
926 	{
927 		.cmd = L2TP_CMD_TUNNEL_DELETE,
928 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
929 		.doit = l2tp_nl_cmd_tunnel_delete,
930 		.flags = GENL_UNS_ADMIN_PERM,
931 	},
932 	{
933 		.cmd = L2TP_CMD_TUNNEL_MODIFY,
934 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
935 		.doit = l2tp_nl_cmd_tunnel_modify,
936 		.flags = GENL_UNS_ADMIN_PERM,
937 	},
938 	{
939 		.cmd = L2TP_CMD_TUNNEL_GET,
940 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
941 		.doit = l2tp_nl_cmd_tunnel_get,
942 		.dumpit = l2tp_nl_cmd_tunnel_dump,
943 		.flags = GENL_UNS_ADMIN_PERM,
944 	},
945 	{
946 		.cmd = L2TP_CMD_SESSION_CREATE,
947 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
948 		.doit = l2tp_nl_cmd_session_create,
949 		.flags = GENL_UNS_ADMIN_PERM,
950 	},
951 	{
952 		.cmd = L2TP_CMD_SESSION_DELETE,
953 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
954 		.doit = l2tp_nl_cmd_session_delete,
955 		.flags = GENL_UNS_ADMIN_PERM,
956 	},
957 	{
958 		.cmd = L2TP_CMD_SESSION_MODIFY,
959 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
960 		.doit = l2tp_nl_cmd_session_modify,
961 		.flags = GENL_UNS_ADMIN_PERM,
962 	},
963 	{
964 		.cmd = L2TP_CMD_SESSION_GET,
965 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
966 		.doit = l2tp_nl_cmd_session_get,
967 		.dumpit = l2tp_nl_cmd_session_dump,
968 		.flags = GENL_UNS_ADMIN_PERM,
969 	},
970 };
971 
972 static struct genl_family l2tp_nl_family __ro_after_init = {
973 	.name		= L2TP_GENL_NAME,
974 	.version	= L2TP_GENL_VERSION,
975 	.hdrsize	= 0,
976 	.maxattr	= L2TP_ATTR_MAX,
977 	.policy = l2tp_nl_policy,
978 	.netnsok	= true,
979 	.module		= THIS_MODULE,
980 	.ops		= l2tp_nl_ops,
981 	.n_ops		= ARRAY_SIZE(l2tp_nl_ops),
982 	.mcgrps		= l2tp_multicast_group,
983 	.n_mcgrps	= ARRAY_SIZE(l2tp_multicast_group),
984 };
985 
986 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops)
987 {
988 	int ret;
989 
990 	ret = -EINVAL;
991 	if (pw_type >= __L2TP_PWTYPE_MAX)
992 		goto err;
993 
994 	genl_lock();
995 	ret = -EBUSY;
996 	if (l2tp_nl_cmd_ops[pw_type])
997 		goto out;
998 
999 	l2tp_nl_cmd_ops[pw_type] = ops;
1000 	ret = 0;
1001 
1002 out:
1003 	genl_unlock();
1004 err:
1005 	return ret;
1006 }
1007 EXPORT_SYMBOL_GPL(l2tp_nl_register_ops);
1008 
1009 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type)
1010 {
1011 	if (pw_type < __L2TP_PWTYPE_MAX) {
1012 		genl_lock();
1013 		l2tp_nl_cmd_ops[pw_type] = NULL;
1014 		genl_unlock();
1015 	}
1016 }
1017 EXPORT_SYMBOL_GPL(l2tp_nl_unregister_ops);
1018 
1019 static int __init l2tp_nl_init(void)
1020 {
1021 	pr_info("L2TP netlink interface\n");
1022 	return genl_register_family(&l2tp_nl_family);
1023 }
1024 
1025 static void l2tp_nl_cleanup(void)
1026 {
1027 	genl_unregister_family(&l2tp_nl_family);
1028 }
1029 
1030 module_init(l2tp_nl_init);
1031 module_exit(l2tp_nl_cleanup);
1032 
1033 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1034 MODULE_DESCRIPTION("L2TP netlink");
1035 MODULE_LICENSE("GPL");
1036 MODULE_VERSION("1.0");
1037 MODULE_ALIAS_GENL_FAMILY("l2tp");
1038