Commit | Line | Data |
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fd558d18 JC |
1 | /* |
2 | * L2TP core. | |
3 | * | |
4 | * Copyright (c) 2008,2009,2010 Katalix Systems Ltd | |
5 | * | |
6 | * This file contains some code of the original L2TPv2 pppol2tp | |
7 | * driver, which has the following copyright: | |
8 | * | |
9 | * Authors: Martijn van Oosterhout <kleptog@svana.org> | |
10 | * James Chapman (jchapman@katalix.com) | |
11 | * Contributors: | |
12 | * Michal Ostrowski <mostrows@speakeasy.net> | |
13 | * Arnaldo Carvalho de Melo <acme@xconectiva.com.br> | |
14 | * David S. Miller (davem@redhat.com) | |
15 | * | |
16 | * This program is free software; you can redistribute it and/or modify | |
17 | * it under the terms of the GNU General Public License version 2 as | |
18 | * published by the Free Software Foundation. | |
19 | */ | |
20 | ||
a4ca44fa JP |
21 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
22 | ||
fd558d18 JC |
23 | #include <linux/module.h> |
24 | #include <linux/string.h> | |
25 | #include <linux/list.h> | |
e02d494d | 26 | #include <linux/rculist.h> |
fd558d18 JC |
27 | #include <linux/uaccess.h> |
28 | ||
29 | #include <linux/kernel.h> | |
30 | #include <linux/spinlock.h> | |
31 | #include <linux/kthread.h> | |
32 | #include <linux/sched.h> | |
33 | #include <linux/slab.h> | |
34 | #include <linux/errno.h> | |
35 | #include <linux/jiffies.h> | |
36 | ||
37 | #include <linux/netdevice.h> | |
38 | #include <linux/net.h> | |
39 | #include <linux/inetdevice.h> | |
40 | #include <linux/skbuff.h> | |
41 | #include <linux/init.h> | |
0d76751f | 42 | #include <linux/in.h> |
fd558d18 JC |
43 | #include <linux/ip.h> |
44 | #include <linux/udp.h> | |
0d76751f | 45 | #include <linux/l2tp.h> |
fd558d18 JC |
46 | #include <linux/hash.h> |
47 | #include <linux/sort.h> | |
48 | #include <linux/file.h> | |
49 | #include <linux/nsproxy.h> | |
50 | #include <net/net_namespace.h> | |
51 | #include <net/netns/generic.h> | |
52 | #include <net/dst.h> | |
53 | #include <net/ip.h> | |
54 | #include <net/udp.h> | |
309795f4 | 55 | #include <net/inet_common.h> |
fd558d18 | 56 | #include <net/xfrm.h> |
0d76751f | 57 | #include <net/protocol.h> |
d2cf3361 BL |
58 | #include <net/inet6_connection_sock.h> |
59 | #include <net/inet_ecn.h> | |
60 | #include <net/ip6_route.h> | |
d499bd2e | 61 | #include <net/ip6_checksum.h> |
fd558d18 JC |
62 | |
63 | #include <asm/byteorder.h> | |
60063497 | 64 | #include <linux/atomic.h> |
fd558d18 JC |
65 | |
66 | #include "l2tp_core.h" | |
67 | ||
68 | #define L2TP_DRV_VERSION "V2.0" | |
69 | ||
70 | /* L2TP header constants */ | |
71 | #define L2TP_HDRFLAG_T 0x8000 | |
72 | #define L2TP_HDRFLAG_L 0x4000 | |
73 | #define L2TP_HDRFLAG_S 0x0800 | |
74 | #define L2TP_HDRFLAG_O 0x0200 | |
75 | #define L2TP_HDRFLAG_P 0x0100 | |
76 | ||
77 | #define L2TP_HDR_VER_MASK 0x000F | |
78 | #define L2TP_HDR_VER_2 0x0002 | |
f7faffa3 | 79 | #define L2TP_HDR_VER_3 0x0003 |
fd558d18 JC |
80 | |
81 | /* L2TPv3 default L2-specific sublayer */ | |
82 | #define L2TP_SLFLAG_S 0x40000000 | |
83 | #define L2TP_SL_SEQ_MASK 0x00ffffff | |
84 | ||
85 | #define L2TP_HDR_SIZE_SEQ 10 | |
86 | #define L2TP_HDR_SIZE_NOSEQ 6 | |
87 | ||
88 | /* Default trace flags */ | |
89 | #define L2TP_DEFAULT_DEBUG_FLAGS 0 | |
90 | ||
fd558d18 JC |
91 | /* Private data stored for received packets in the skb. |
92 | */ | |
93 | struct l2tp_skb_cb { | |
f7faffa3 | 94 | u32 ns; |
fd558d18 JC |
95 | u16 has_seq; |
96 | u16 length; | |
97 | unsigned long expires; | |
98 | }; | |
99 | ||
100 | #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) | |
101 | ||
102 | static atomic_t l2tp_tunnel_count; | |
103 | static atomic_t l2tp_session_count; | |
104 | ||
105 | /* per-net private data for this module */ | |
106 | static unsigned int l2tp_net_id; | |
107 | struct l2tp_net { | |
108 | struct list_head l2tp_tunnel_list; | |
e02d494d | 109 | spinlock_t l2tp_tunnel_list_lock; |
f7faffa3 | 110 | struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2]; |
e02d494d | 111 | spinlock_t l2tp_session_hlist_lock; |
fd558d18 JC |
112 | }; |
113 | ||
fc130840 | 114 | static void l2tp_session_set_header_len(struct l2tp_session *session, int version); |
115 | static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); | |
116 | static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); | |
117 | ||
fd558d18 JC |
118 | static inline struct l2tp_net *l2tp_pernet(struct net *net) |
119 | { | |
120 | BUG_ON(!net); | |
121 | ||
122 | return net_generic(net, l2tp_net_id); | |
123 | } | |
124 | ||
fc130840 | 125 | |
126 | /* Tunnel reference counts. Incremented per session that is added to | |
127 | * the tunnel. | |
128 | */ | |
129 | static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel) | |
130 | { | |
131 | atomic_inc(&tunnel->ref_count); | |
132 | } | |
133 | ||
134 | static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel) | |
135 | { | |
136 | if (atomic_dec_and_test(&tunnel->ref_count)) | |
137 | l2tp_tunnel_free(tunnel); | |
138 | } | |
139 | #ifdef L2TP_REFCNT_DEBUG | |
a4ca44fa JP |
140 | #define l2tp_tunnel_inc_refcount(_t) \ |
141 | do { \ | |
142 | pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \ | |
143 | __func__, __LINE__, (_t)->name, \ | |
144 | atomic_read(&_t->ref_count)); \ | |
145 | l2tp_tunnel_inc_refcount_1(_t); \ | |
146 | } while (0) | |
147 | #define l2tp_tunnel_dec_refcount(_t) | |
148 | do { \ | |
149 | pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \ | |
150 | __func__, __LINE__, (_t)->name, \ | |
151 | atomic_read(&_t->ref_count)); \ | |
152 | l2tp_tunnel_dec_refcount_1(_t); \ | |
153 | } while (0) | |
fc130840 | 154 | #else |
155 | #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t) | |
156 | #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t) | |
157 | #endif | |
158 | ||
f7faffa3 JC |
159 | /* Session hash global list for L2TPv3. |
160 | * The session_id SHOULD be random according to RFC3931, but several | |
161 | * L2TP implementations use incrementing session_ids. So we do a real | |
162 | * hash on the session_id, rather than a simple bitmask. | |
163 | */ | |
164 | static inline struct hlist_head * | |
165 | l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id) | |
166 | { | |
167 | return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)]; | |
168 | ||
169 | } | |
170 | ||
171 | /* Lookup a session by id in the global session list | |
172 | */ | |
173 | static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id) | |
174 | { | |
175 | struct l2tp_net *pn = l2tp_pernet(net); | |
176 | struct hlist_head *session_list = | |
177 | l2tp_session_id_hash_2(pn, session_id); | |
178 | struct l2tp_session *session; | |
179 | struct hlist_node *walk; | |
180 | ||
e02d494d JC |
181 | rcu_read_lock_bh(); |
182 | hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) { | |
f7faffa3 | 183 | if (session->session_id == session_id) { |
e02d494d | 184 | rcu_read_unlock_bh(); |
f7faffa3 JC |
185 | return session; |
186 | } | |
187 | } | |
e02d494d | 188 | rcu_read_unlock_bh(); |
f7faffa3 JC |
189 | |
190 | return NULL; | |
191 | } | |
192 | ||
fd558d18 JC |
193 | /* Session hash list. |
194 | * The session_id SHOULD be random according to RFC2661, but several | |
195 | * L2TP implementations (Cisco and Microsoft) use incrementing | |
196 | * session_ids. So we do a real hash on the session_id, rather than a | |
197 | * simple bitmask. | |
198 | */ | |
199 | static inline struct hlist_head * | |
200 | l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) | |
201 | { | |
202 | return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; | |
203 | } | |
204 | ||
205 | /* Lookup a session by id | |
206 | */ | |
f7faffa3 | 207 | struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id) |
fd558d18 | 208 | { |
f7faffa3 | 209 | struct hlist_head *session_list; |
fd558d18 JC |
210 | struct l2tp_session *session; |
211 | struct hlist_node *walk; | |
212 | ||
f7faffa3 JC |
213 | /* In L2TPv3, session_ids are unique over all tunnels and we |
214 | * sometimes need to look them up before we know the | |
215 | * tunnel. | |
216 | */ | |
217 | if (tunnel == NULL) | |
218 | return l2tp_session_find_2(net, session_id); | |
219 | ||
220 | session_list = l2tp_session_id_hash(tunnel, session_id); | |
fd558d18 JC |
221 | read_lock_bh(&tunnel->hlist_lock); |
222 | hlist_for_each_entry(session, walk, session_list, hlist) { | |
223 | if (session->session_id == session_id) { | |
224 | read_unlock_bh(&tunnel->hlist_lock); | |
225 | return session; | |
226 | } | |
227 | } | |
228 | read_unlock_bh(&tunnel->hlist_lock); | |
229 | ||
230 | return NULL; | |
231 | } | |
232 | EXPORT_SYMBOL_GPL(l2tp_session_find); | |
233 | ||
234 | struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth) | |
235 | { | |
236 | int hash; | |
237 | struct hlist_node *walk; | |
238 | struct l2tp_session *session; | |
239 | int count = 0; | |
240 | ||
241 | read_lock_bh(&tunnel->hlist_lock); | |
242 | for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { | |
243 | hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) { | |
244 | if (++count > nth) { | |
245 | read_unlock_bh(&tunnel->hlist_lock); | |
246 | return session; | |
247 | } | |
248 | } | |
249 | } | |
250 | ||
251 | read_unlock_bh(&tunnel->hlist_lock); | |
252 | ||
253 | return NULL; | |
254 | } | |
255 | EXPORT_SYMBOL_GPL(l2tp_session_find_nth); | |
256 | ||
309795f4 JC |
257 | /* Lookup a session by interface name. |
258 | * This is very inefficient but is only used by management interfaces. | |
259 | */ | |
260 | struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname) | |
261 | { | |
262 | struct l2tp_net *pn = l2tp_pernet(net); | |
263 | int hash; | |
264 | struct hlist_node *walk; | |
265 | struct l2tp_session *session; | |
266 | ||
e02d494d | 267 | rcu_read_lock_bh(); |
309795f4 | 268 | for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) { |
e02d494d | 269 | hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) { |
309795f4 | 270 | if (!strcmp(session->ifname, ifname)) { |
e02d494d | 271 | rcu_read_unlock_bh(); |
309795f4 JC |
272 | return session; |
273 | } | |
274 | } | |
275 | } | |
276 | ||
e02d494d | 277 | rcu_read_unlock_bh(); |
309795f4 JC |
278 | |
279 | return NULL; | |
280 | } | |
281 | EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname); | |
282 | ||
fd558d18 JC |
283 | /* Lookup a tunnel by id |
284 | */ | |
285 | struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id) | |
286 | { | |
287 | struct l2tp_tunnel *tunnel; | |
288 | struct l2tp_net *pn = l2tp_pernet(net); | |
289 | ||
e02d494d JC |
290 | rcu_read_lock_bh(); |
291 | list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { | |
fd558d18 | 292 | if (tunnel->tunnel_id == tunnel_id) { |
e02d494d | 293 | rcu_read_unlock_bh(); |
fd558d18 JC |
294 | return tunnel; |
295 | } | |
296 | } | |
e02d494d | 297 | rcu_read_unlock_bh(); |
fd558d18 JC |
298 | |
299 | return NULL; | |
300 | } | |
301 | EXPORT_SYMBOL_GPL(l2tp_tunnel_find); | |
302 | ||
303 | struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth) | |
304 | { | |
305 | struct l2tp_net *pn = l2tp_pernet(net); | |
306 | struct l2tp_tunnel *tunnel; | |
307 | int count = 0; | |
308 | ||
e02d494d JC |
309 | rcu_read_lock_bh(); |
310 | list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { | |
fd558d18 | 311 | if (++count > nth) { |
e02d494d | 312 | rcu_read_unlock_bh(); |
fd558d18 JC |
313 | return tunnel; |
314 | } | |
315 | } | |
316 | ||
e02d494d | 317 | rcu_read_unlock_bh(); |
fd558d18 JC |
318 | |
319 | return NULL; | |
320 | } | |
321 | EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); | |
322 | ||
323 | /***************************************************************************** | |
324 | * Receive data handling | |
325 | *****************************************************************************/ | |
326 | ||
327 | /* Queue a skb in order. We come here only if the skb has an L2TP sequence | |
328 | * number. | |
329 | */ | |
330 | static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) | |
331 | { | |
332 | struct sk_buff *skbp; | |
333 | struct sk_buff *tmp; | |
f7faffa3 | 334 | u32 ns = L2TP_SKB_CB(skb)->ns; |
5de7aee5 | 335 | struct l2tp_stats *sstats; |
fd558d18 JC |
336 | |
337 | spin_lock_bh(&session->reorder_q.lock); | |
5de7aee5 | 338 | sstats = &session->stats; |
fd558d18 JC |
339 | skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { |
340 | if (L2TP_SKB_CB(skbp)->ns > ns) { | |
341 | __skb_queue_before(&session->reorder_q, skbp, skb); | |
a4ca44fa JP |
342 | l2tp_dbg(session, L2TP_MSG_SEQ, |
343 | "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", | |
344 | session->name, ns, L2TP_SKB_CB(skbp)->ns, | |
345 | skb_queue_len(&session->reorder_q)); | |
5de7aee5 JC |
346 | u64_stats_update_begin(&sstats->syncp); |
347 | sstats->rx_oos_packets++; | |
348 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
349 | goto out; |
350 | } | |
351 | } | |
352 | ||
353 | __skb_queue_tail(&session->reorder_q, skb); | |
354 | ||
355 | out: | |
356 | spin_unlock_bh(&session->reorder_q.lock); | |
357 | } | |
358 | ||
359 | /* Dequeue a single skb. | |
360 | */ | |
361 | static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) | |
362 | { | |
363 | struct l2tp_tunnel *tunnel = session->tunnel; | |
364 | int length = L2TP_SKB_CB(skb)->length; | |
5de7aee5 | 365 | struct l2tp_stats *tstats, *sstats; |
fd558d18 JC |
366 | |
367 | /* We're about to requeue the skb, so return resources | |
368 | * to its current owner (a socket receive buffer). | |
369 | */ | |
370 | skb_orphan(skb); | |
371 | ||
5de7aee5 JC |
372 | tstats = &tunnel->stats; |
373 | u64_stats_update_begin(&tstats->syncp); | |
374 | sstats = &session->stats; | |
375 | u64_stats_update_begin(&sstats->syncp); | |
376 | tstats->rx_packets++; | |
377 | tstats->rx_bytes += length; | |
378 | sstats->rx_packets++; | |
379 | sstats->rx_bytes += length; | |
380 | u64_stats_update_end(&tstats->syncp); | |
381 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
382 | |
383 | if (L2TP_SKB_CB(skb)->has_seq) { | |
384 | /* Bump our Nr */ | |
385 | session->nr++; | |
f7faffa3 JC |
386 | if (tunnel->version == L2TP_HDR_VER_2) |
387 | session->nr &= 0xffff; | |
388 | else | |
389 | session->nr &= 0xffffff; | |
390 | ||
a4ca44fa JP |
391 | l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n", |
392 | session->name, session->nr); | |
fd558d18 JC |
393 | } |
394 | ||
395 | /* call private receive handler */ | |
396 | if (session->recv_skb != NULL) | |
397 | (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); | |
398 | else | |
399 | kfree_skb(skb); | |
400 | ||
401 | if (session->deref) | |
402 | (*session->deref)(session); | |
403 | } | |
404 | ||
405 | /* Dequeue skbs from the session's reorder_q, subject to packet order. | |
406 | * Skbs that have been in the queue for too long are simply discarded. | |
407 | */ | |
408 | static void l2tp_recv_dequeue(struct l2tp_session *session) | |
409 | { | |
410 | struct sk_buff *skb; | |
411 | struct sk_buff *tmp; | |
5de7aee5 | 412 | struct l2tp_stats *sstats; |
fd558d18 JC |
413 | |
414 | /* If the pkt at the head of the queue has the nr that we | |
415 | * expect to send up next, dequeue it and any other | |
416 | * in-sequence packets behind it. | |
417 | */ | |
e2e210c0 | 418 | start: |
fd558d18 | 419 | spin_lock_bh(&session->reorder_q.lock); |
5de7aee5 | 420 | sstats = &session->stats; |
fd558d18 JC |
421 | skb_queue_walk_safe(&session->reorder_q, skb, tmp) { |
422 | if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { | |
5de7aee5 JC |
423 | u64_stats_update_begin(&sstats->syncp); |
424 | sstats->rx_seq_discards++; | |
425 | sstats->rx_errors++; | |
426 | u64_stats_update_end(&sstats->syncp); | |
a4ca44fa JP |
427 | l2tp_dbg(session, L2TP_MSG_SEQ, |
428 | "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n", | |
429 | session->name, L2TP_SKB_CB(skb)->ns, | |
430 | L2TP_SKB_CB(skb)->length, session->nr, | |
431 | skb_queue_len(&session->reorder_q)); | |
38d40b3f | 432 | session->reorder_skip = 1; |
fd558d18 JC |
433 | __skb_unlink(skb, &session->reorder_q); |
434 | kfree_skb(skb); | |
435 | if (session->deref) | |
436 | (*session->deref)(session); | |
437 | continue; | |
438 | } | |
439 | ||
440 | if (L2TP_SKB_CB(skb)->has_seq) { | |
38d40b3f | 441 | if (session->reorder_skip) { |
a4ca44fa JP |
442 | l2tp_dbg(session, L2TP_MSG_SEQ, |
443 | "%s: advancing nr to next pkt: %u -> %u", | |
444 | session->name, session->nr, | |
445 | L2TP_SKB_CB(skb)->ns); | |
38d40b3f JC |
446 | session->reorder_skip = 0; |
447 | session->nr = L2TP_SKB_CB(skb)->ns; | |
448 | } | |
fd558d18 | 449 | if (L2TP_SKB_CB(skb)->ns != session->nr) { |
a4ca44fa JP |
450 | l2tp_dbg(session, L2TP_MSG_SEQ, |
451 | "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n", | |
452 | session->name, L2TP_SKB_CB(skb)->ns, | |
453 | L2TP_SKB_CB(skb)->length, session->nr, | |
454 | skb_queue_len(&session->reorder_q)); | |
fd558d18 JC |
455 | goto out; |
456 | } | |
457 | } | |
458 | __skb_unlink(skb, &session->reorder_q); | |
459 | ||
460 | /* Process the skb. We release the queue lock while we | |
461 | * do so to let other contexts process the queue. | |
462 | */ | |
463 | spin_unlock_bh(&session->reorder_q.lock); | |
464 | l2tp_recv_dequeue_skb(session, skb); | |
e2e210c0 | 465 | goto start; |
fd558d18 JC |
466 | } |
467 | ||
468 | out: | |
469 | spin_unlock_bh(&session->reorder_q.lock); | |
470 | } | |
471 | ||
472 | static inline int l2tp_verify_udp_checksum(struct sock *sk, | |
473 | struct sk_buff *skb) | |
474 | { | |
475 | struct udphdr *uh = udp_hdr(skb); | |
476 | u16 ulen = ntohs(uh->len); | |
fd558d18 JC |
477 | __wsum psum; |
478 | ||
d2cf3361 | 479 | if (sk->sk_no_check || skb_csum_unnecessary(skb)) |
fd558d18 JC |
480 | return 0; |
481 | ||
d2cf3361 BL |
482 | #if IS_ENABLED(CONFIG_IPV6) |
483 | if (sk->sk_family == PF_INET6) { | |
484 | if (!uh->check) { | |
485 | LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n"); | |
486 | return 1; | |
487 | } | |
488 | if ((skb->ip_summed == CHECKSUM_COMPLETE) && | |
489 | !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, | |
490 | &ipv6_hdr(skb)->daddr, ulen, | |
491 | IPPROTO_UDP, skb->csum)) { | |
492 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
493 | return 0; | |
494 | } | |
495 | skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr, | |
496 | &ipv6_hdr(skb)->daddr, | |
497 | skb->len, IPPROTO_UDP, | |
498 | 0)); | |
499 | } else | |
500 | #endif | |
501 | { | |
502 | struct inet_sock *inet; | |
503 | if (!uh->check) | |
504 | return 0; | |
505 | inet = inet_sk(sk); | |
506 | psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, | |
507 | ulen, IPPROTO_UDP, 0); | |
508 | ||
509 | if ((skb->ip_summed == CHECKSUM_COMPLETE) && | |
510 | !csum_fold(csum_add(psum, skb->csum))) | |
511 | return 0; | |
512 | skb->csum = psum; | |
513 | } | |
fd558d18 JC |
514 | |
515 | return __skb_checksum_complete(skb); | |
516 | } | |
517 | ||
f7faffa3 JC |
518 | /* Do receive processing of L2TP data frames. We handle both L2TPv2 |
519 | * and L2TPv3 data frames here. | |
520 | * | |
521 | * L2TPv2 Data Message Header | |
522 | * | |
523 | * 0 1 2 3 | |
524 | * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |
525 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
526 | * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | | |
527 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
528 | * | Tunnel ID | Session ID | | |
529 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
530 | * | Ns (opt) | Nr (opt) | | |
531 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
532 | * | Offset Size (opt) | Offset pad... (opt) | |
533 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
534 | * | |
535 | * Data frames are marked by T=0. All other fields are the same as | |
536 | * those in L2TP control frames. | |
537 | * | |
538 | * L2TPv3 Data Message Header | |
539 | * | |
540 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
541 | * | L2TP Session Header | | |
542 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
543 | * | L2-Specific Sublayer | | |
544 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
545 | * | Tunnel Payload ... | |
546 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
547 | * | |
548 | * L2TPv3 Session Header Over IP | |
549 | * | |
550 | * 0 1 2 3 | |
551 | * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |
552 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
553 | * | Session ID | | |
554 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
555 | * | Cookie (optional, maximum 64 bits)... | |
556 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
557 | * | | |
558 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
559 | * | |
560 | * L2TPv3 L2-Specific Sublayer Format | |
561 | * | |
562 | * 0 1 2 3 | |
563 | * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |
564 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
565 | * |x|S|x|x|x|x|x|x| Sequence Number | | |
566 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
567 | * | |
568 | * Cookie value, sublayer format and offset (pad) are negotiated with | |
569 | * the peer when the session is set up. Unlike L2TPv2, we do not need | |
570 | * to parse the packet header to determine if optional fields are | |
571 | * present. | |
572 | * | |
573 | * Caller must already have parsed the frame and determined that it is | |
574 | * a data (not control) frame before coming here. Fields up to the | |
575 | * session-id have already been parsed and ptr points to the data | |
576 | * after the session-id. | |
fd558d18 | 577 | */ |
f7faffa3 JC |
578 | void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, |
579 | unsigned char *ptr, unsigned char *optr, u16 hdrflags, | |
580 | int length, int (*payload_hook)(struct sk_buff *skb)) | |
fd558d18 | 581 | { |
f7faffa3 | 582 | struct l2tp_tunnel *tunnel = session->tunnel; |
fd558d18 | 583 | int offset; |
f7faffa3 | 584 | u32 ns, nr; |
5de7aee5 | 585 | struct l2tp_stats *sstats = &session->stats; |
fd558d18 JC |
586 | |
587 | /* The ref count is increased since we now hold a pointer to | |
588 | * the session. Take care to decrement the refcnt when exiting | |
589 | * this function from now on... | |
590 | */ | |
591 | l2tp_session_inc_refcount(session); | |
592 | if (session->ref) | |
593 | (*session->ref)(session); | |
594 | ||
f7faffa3 JC |
595 | /* Parse and check optional cookie */ |
596 | if (session->peer_cookie_len > 0) { | |
597 | if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { | |
a4ca44fa JP |
598 | l2tp_info(tunnel, L2TP_MSG_DATA, |
599 | "%s: cookie mismatch (%u/%u). Discarding.\n", | |
600 | tunnel->name, tunnel->tunnel_id, | |
601 | session->session_id); | |
5de7aee5 JC |
602 | u64_stats_update_begin(&sstats->syncp); |
603 | sstats->rx_cookie_discards++; | |
604 | u64_stats_update_end(&sstats->syncp); | |
f7faffa3 JC |
605 | goto discard; |
606 | } | |
607 | ptr += session->peer_cookie_len; | |
608 | } | |
609 | ||
fd558d18 JC |
610 | /* Handle the optional sequence numbers. Sequence numbers are |
611 | * in different places for L2TPv2 and L2TPv3. | |
612 | * | |
613 | * If we are the LAC, enable/disable sequence numbers under | |
614 | * the control of the LNS. If no sequence numbers present but | |
615 | * we were expecting them, discard frame. | |
616 | */ | |
617 | ns = nr = 0; | |
618 | L2TP_SKB_CB(skb)->has_seq = 0; | |
f7faffa3 JC |
619 | if (tunnel->version == L2TP_HDR_VER_2) { |
620 | if (hdrflags & L2TP_HDRFLAG_S) { | |
621 | ns = ntohs(*(__be16 *) ptr); | |
622 | ptr += 2; | |
623 | nr = ntohs(*(__be16 *) ptr); | |
624 | ptr += 2; | |
fd558d18 | 625 | |
f7faffa3 JC |
626 | /* Store L2TP info in the skb */ |
627 | L2TP_SKB_CB(skb)->ns = ns; | |
628 | L2TP_SKB_CB(skb)->has_seq = 1; | |
fd558d18 | 629 | |
a4ca44fa JP |
630 | l2tp_dbg(session, L2TP_MSG_SEQ, |
631 | "%s: recv data ns=%u, nr=%u, session nr=%u\n", | |
632 | session->name, ns, nr, session->nr); | |
f7faffa3 JC |
633 | } |
634 | } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { | |
635 | u32 l2h = ntohl(*(__be32 *) ptr); | |
636 | ||
637 | if (l2h & 0x40000000) { | |
638 | ns = l2h & 0x00ffffff; | |
639 | ||
640 | /* Store L2TP info in the skb */ | |
641 | L2TP_SKB_CB(skb)->ns = ns; | |
642 | L2TP_SKB_CB(skb)->has_seq = 1; | |
643 | ||
a4ca44fa JP |
644 | l2tp_dbg(session, L2TP_MSG_SEQ, |
645 | "%s: recv data ns=%u, session nr=%u\n", | |
646 | session->name, ns, session->nr); | |
f7faffa3 | 647 | } |
fd558d18 JC |
648 | } |
649 | ||
f7faffa3 JC |
650 | /* Advance past L2-specific header, if present */ |
651 | ptr += session->l2specific_len; | |
652 | ||
fd558d18 JC |
653 | if (L2TP_SKB_CB(skb)->has_seq) { |
654 | /* Received a packet with sequence numbers. If we're the LNS, | |
655 | * check if we sre sending sequence numbers and if not, | |
656 | * configure it so. | |
657 | */ | |
658 | if ((!session->lns_mode) && (!session->send_seq)) { | |
a4ca44fa JP |
659 | l2tp_info(session, L2TP_MSG_SEQ, |
660 | "%s: requested to enable seq numbers by LNS\n", | |
661 | session->name); | |
fd558d18 | 662 | session->send_seq = -1; |
f7faffa3 | 663 | l2tp_session_set_header_len(session, tunnel->version); |
fd558d18 JC |
664 | } |
665 | } else { | |
666 | /* No sequence numbers. | |
667 | * If user has configured mandatory sequence numbers, discard. | |
668 | */ | |
669 | if (session->recv_seq) { | |
a4ca44fa JP |
670 | l2tp_warn(session, L2TP_MSG_SEQ, |
671 | "%s: recv data has no seq numbers when required. Discarding.\n", | |
672 | session->name); | |
5de7aee5 JC |
673 | u64_stats_update_begin(&sstats->syncp); |
674 | sstats->rx_seq_discards++; | |
675 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
676 | goto discard; |
677 | } | |
678 | ||
679 | /* If we're the LAC and we're sending sequence numbers, the | |
680 | * LNS has requested that we no longer send sequence numbers. | |
681 | * If we're the LNS and we're sending sequence numbers, the | |
682 | * LAC is broken. Discard the frame. | |
683 | */ | |
684 | if ((!session->lns_mode) && (session->send_seq)) { | |
a4ca44fa JP |
685 | l2tp_info(session, L2TP_MSG_SEQ, |
686 | "%s: requested to disable seq numbers by LNS\n", | |
687 | session->name); | |
fd558d18 | 688 | session->send_seq = 0; |
f7faffa3 | 689 | l2tp_session_set_header_len(session, tunnel->version); |
fd558d18 | 690 | } else if (session->send_seq) { |
a4ca44fa JP |
691 | l2tp_warn(session, L2TP_MSG_SEQ, |
692 | "%s: recv data has no seq numbers when required. Discarding.\n", | |
693 | session->name); | |
5de7aee5 JC |
694 | u64_stats_update_begin(&sstats->syncp); |
695 | sstats->rx_seq_discards++; | |
696 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
697 | goto discard; |
698 | } | |
699 | } | |
700 | ||
f7faffa3 JC |
701 | /* Session data offset is handled differently for L2TPv2 and |
702 | * L2TPv3. For L2TPv2, there is an optional 16-bit value in | |
703 | * the header. For L2TPv3, the offset is negotiated using AVPs | |
704 | * in the session setup control protocol. | |
705 | */ | |
706 | if (tunnel->version == L2TP_HDR_VER_2) { | |
707 | /* If offset bit set, skip it. */ | |
708 | if (hdrflags & L2TP_HDRFLAG_O) { | |
709 | offset = ntohs(*(__be16 *)ptr); | |
710 | ptr += 2 + offset; | |
711 | } | |
712 | } else | |
713 | ptr += session->offset; | |
fd558d18 JC |
714 | |
715 | offset = ptr - optr; | |
716 | if (!pskb_may_pull(skb, offset)) | |
717 | goto discard; | |
718 | ||
719 | __skb_pull(skb, offset); | |
720 | ||
721 | /* If caller wants to process the payload before we queue the | |
722 | * packet, do so now. | |
723 | */ | |
724 | if (payload_hook) | |
725 | if ((*payload_hook)(skb)) | |
726 | goto discard; | |
727 | ||
728 | /* Prepare skb for adding to the session's reorder_q. Hold | |
729 | * packets for max reorder_timeout or 1 second if not | |
730 | * reordering. | |
731 | */ | |
732 | L2TP_SKB_CB(skb)->length = length; | |
733 | L2TP_SKB_CB(skb)->expires = jiffies + | |
734 | (session->reorder_timeout ? session->reorder_timeout : HZ); | |
735 | ||
736 | /* Add packet to the session's receive queue. Reordering is done here, if | |
737 | * enabled. Saved L2TP protocol info is stored in skb->sb[]. | |
738 | */ | |
739 | if (L2TP_SKB_CB(skb)->has_seq) { | |
740 | if (session->reorder_timeout != 0) { | |
741 | /* Packet reordering enabled. Add skb to session's | |
742 | * reorder queue, in order of ns. | |
743 | */ | |
744 | l2tp_recv_queue_skb(session, skb); | |
745 | } else { | |
746 | /* Packet reordering disabled. Discard out-of-sequence | |
747 | * packets | |
748 | */ | |
749 | if (L2TP_SKB_CB(skb)->ns != session->nr) { | |
5de7aee5 JC |
750 | u64_stats_update_begin(&sstats->syncp); |
751 | sstats->rx_seq_discards++; | |
752 | u64_stats_update_end(&sstats->syncp); | |
a4ca44fa JP |
753 | l2tp_dbg(session, L2TP_MSG_SEQ, |
754 | "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n", | |
755 | session->name, L2TP_SKB_CB(skb)->ns, | |
756 | L2TP_SKB_CB(skb)->length, session->nr, | |
757 | skb_queue_len(&session->reorder_q)); | |
fd558d18 JC |
758 | goto discard; |
759 | } | |
760 | skb_queue_tail(&session->reorder_q, skb); | |
761 | } | |
762 | } else { | |
763 | /* No sequence numbers. Add the skb to the tail of the | |
764 | * reorder queue. This ensures that it will be | |
765 | * delivered after all previous sequenced skbs. | |
766 | */ | |
767 | skb_queue_tail(&session->reorder_q, skb); | |
768 | } | |
769 | ||
770 | /* Try to dequeue as many skbs from reorder_q as we can. */ | |
771 | l2tp_recv_dequeue(session); | |
772 | ||
773 | l2tp_session_dec_refcount(session); | |
774 | ||
f7faffa3 | 775 | return; |
fd558d18 JC |
776 | |
777 | discard: | |
5de7aee5 JC |
778 | u64_stats_update_begin(&sstats->syncp); |
779 | sstats->rx_errors++; | |
780 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
781 | kfree_skb(skb); |
782 | ||
783 | if (session->deref) | |
784 | (*session->deref)(session); | |
785 | ||
786 | l2tp_session_dec_refcount(session); | |
f7faffa3 JC |
787 | } |
788 | EXPORT_SYMBOL(l2tp_recv_common); | |
789 | ||
790 | /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame | |
791 | * here. The skb is not on a list when we get here. | |
792 | * Returns 0 if the packet was a data packet and was successfully passed on. | |
793 | * Returns 1 if the packet was not a good data packet and could not be | |
794 | * forwarded. All such packets are passed up to userspace to deal with. | |
795 | */ | |
fc130840 | 796 | static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, |
797 | int (*payload_hook)(struct sk_buff *skb)) | |
f7faffa3 JC |
798 | { |
799 | struct l2tp_session *session = NULL; | |
800 | unsigned char *ptr, *optr; | |
801 | u16 hdrflags; | |
802 | u32 tunnel_id, session_id; | |
f7faffa3 JC |
803 | u16 version; |
804 | int length; | |
5de7aee5 | 805 | struct l2tp_stats *tstats; |
f7faffa3 JC |
806 | |
807 | if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb)) | |
808 | goto discard_bad_csum; | |
809 | ||
810 | /* UDP always verifies the packet length. */ | |
811 | __skb_pull(skb, sizeof(struct udphdr)); | |
812 | ||
813 | /* Short packet? */ | |
814 | if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { | |
a4ca44fa JP |
815 | l2tp_info(tunnel, L2TP_MSG_DATA, |
816 | "%s: recv short packet (len=%d)\n", | |
817 | tunnel->name, skb->len); | |
f7faffa3 JC |
818 | goto error; |
819 | } | |
820 | ||
f7faffa3 JC |
821 | /* Trace packet contents, if enabled */ |
822 | if (tunnel->debug & L2TP_MSG_DATA) { | |
823 | length = min(32u, skb->len); | |
824 | if (!pskb_may_pull(skb, length)) | |
825 | goto error; | |
826 | ||
a4ca44fa JP |
827 | pr_debug("%s: recv\n", tunnel->name); |
828 | print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length); | |
f7faffa3 JC |
829 | } |
830 | ||
e50e705c ED |
831 | /* Point to L2TP header */ |
832 | optr = ptr = skb->data; | |
833 | ||
f7faffa3 JC |
834 | /* Get L2TP header flags */ |
835 | hdrflags = ntohs(*(__be16 *) ptr); | |
836 | ||
837 | /* Check protocol version */ | |
838 | version = hdrflags & L2TP_HDR_VER_MASK; | |
839 | if (version != tunnel->version) { | |
a4ca44fa JP |
840 | l2tp_info(tunnel, L2TP_MSG_DATA, |
841 | "%s: recv protocol version mismatch: got %d expected %d\n", | |
842 | tunnel->name, version, tunnel->version); | |
f7faffa3 JC |
843 | goto error; |
844 | } | |
845 | ||
846 | /* Get length of L2TP packet */ | |
847 | length = skb->len; | |
848 | ||
849 | /* If type is control packet, it is handled by userspace. */ | |
850 | if (hdrflags & L2TP_HDRFLAG_T) { | |
a4ca44fa JP |
851 | l2tp_dbg(tunnel, L2TP_MSG_DATA, |
852 | "%s: recv control packet, len=%d\n", | |
853 | tunnel->name, length); | |
f7faffa3 JC |
854 | goto error; |
855 | } | |
856 | ||
857 | /* Skip flags */ | |
858 | ptr += 2; | |
859 | ||
860 | if (tunnel->version == L2TP_HDR_VER_2) { | |
861 | /* If length is present, skip it */ | |
862 | if (hdrflags & L2TP_HDRFLAG_L) | |
863 | ptr += 2; | |
864 | ||
865 | /* Extract tunnel and session ID */ | |
866 | tunnel_id = ntohs(*(__be16 *) ptr); | |
867 | ptr += 2; | |
868 | session_id = ntohs(*(__be16 *) ptr); | |
869 | ptr += 2; | |
870 | } else { | |
871 | ptr += 2; /* skip reserved bits */ | |
872 | tunnel_id = tunnel->tunnel_id; | |
873 | session_id = ntohl(*(__be32 *) ptr); | |
874 | ptr += 4; | |
875 | } | |
876 | ||
877 | /* Find the session context */ | |
878 | session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id); | |
309795f4 | 879 | if (!session || !session->recv_skb) { |
f7faffa3 | 880 | /* Not found? Pass to userspace to deal with */ |
a4ca44fa JP |
881 | l2tp_info(tunnel, L2TP_MSG_DATA, |
882 | "%s: no session found (%u/%u). Passing up.\n", | |
883 | tunnel->name, tunnel_id, session_id); | |
f7faffa3 JC |
884 | goto error; |
885 | } | |
886 | ||
887 | l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); | |
fd558d18 JC |
888 | |
889 | return 0; | |
890 | ||
891 | discard_bad_csum: | |
892 | LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); | |
893 | UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0); | |
5de7aee5 JC |
894 | tstats = &tunnel->stats; |
895 | u64_stats_update_begin(&tstats->syncp); | |
896 | tstats->rx_errors++; | |
897 | u64_stats_update_end(&tstats->syncp); | |
fd558d18 JC |
898 | kfree_skb(skb); |
899 | ||
900 | return 0; | |
901 | ||
902 | error: | |
903 | /* Put UDP header back */ | |
904 | __skb_push(skb, sizeof(struct udphdr)); | |
905 | ||
906 | return 1; | |
907 | } | |
fd558d18 JC |
908 | |
909 | /* UDP encapsulation receive handler. See net/ipv4/udp.c. | |
910 | * Return codes: | |
911 | * 0 : success. | |
912 | * <0: error | |
913 | * >0: skb should be passed up to userspace as UDP. | |
914 | */ | |
915 | int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) | |
916 | { | |
917 | struct l2tp_tunnel *tunnel; | |
918 | ||
919 | tunnel = l2tp_sock_to_tunnel(sk); | |
920 | if (tunnel == NULL) | |
921 | goto pass_up; | |
922 | ||
a4ca44fa JP |
923 | l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n", |
924 | tunnel->name, skb->len); | |
fd558d18 JC |
925 | |
926 | if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) | |
927 | goto pass_up_put; | |
928 | ||
929 | sock_put(sk); | |
930 | return 0; | |
931 | ||
932 | pass_up_put: | |
933 | sock_put(sk); | |
934 | pass_up: | |
935 | return 1; | |
936 | } | |
937 | EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); | |
938 | ||
939 | /************************************************************************ | |
940 | * Transmit handling | |
941 | ***********************************************************************/ | |
942 | ||
943 | /* Build an L2TP header for the session into the buffer provided. | |
944 | */ | |
f7faffa3 | 945 | static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) |
fd558d18 | 946 | { |
f7faffa3 | 947 | struct l2tp_tunnel *tunnel = session->tunnel; |
fd558d18 | 948 | __be16 *bufp = buf; |
f7faffa3 | 949 | __be16 *optr = buf; |
fd558d18 JC |
950 | u16 flags = L2TP_HDR_VER_2; |
951 | u32 tunnel_id = tunnel->peer_tunnel_id; | |
952 | u32 session_id = session->peer_session_id; | |
953 | ||
954 | if (session->send_seq) | |
955 | flags |= L2TP_HDRFLAG_S; | |
956 | ||
957 | /* Setup L2TP header. */ | |
958 | *bufp++ = htons(flags); | |
959 | *bufp++ = htons(tunnel_id); | |
960 | *bufp++ = htons(session_id); | |
961 | if (session->send_seq) { | |
962 | *bufp++ = htons(session->ns); | |
963 | *bufp++ = 0; | |
964 | session->ns++; | |
f7faffa3 | 965 | session->ns &= 0xffff; |
a4ca44fa JP |
966 | l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n", |
967 | session->name, session->ns); | |
fd558d18 | 968 | } |
f7faffa3 JC |
969 | |
970 | return bufp - optr; | |
fd558d18 JC |
971 | } |
972 | ||
f7faffa3 | 973 | static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) |
fd558d18 | 974 | { |
0d76751f | 975 | struct l2tp_tunnel *tunnel = session->tunnel; |
f7faffa3 JC |
976 | char *bufp = buf; |
977 | char *optr = bufp; | |
f7faffa3 | 978 | |
0d76751f JC |
979 | /* Setup L2TP header. The header differs slightly for UDP and |
980 | * IP encapsulations. For UDP, there is 4 bytes of flags. | |
981 | */ | |
982 | if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { | |
983 | u16 flags = L2TP_HDR_VER_3; | |
984 | *((__be16 *) bufp) = htons(flags); | |
985 | bufp += 2; | |
986 | *((__be16 *) bufp) = 0; | |
987 | bufp += 2; | |
988 | } | |
989 | ||
f7faffa3 JC |
990 | *((__be32 *) bufp) = htonl(session->peer_session_id); |
991 | bufp += 4; | |
992 | if (session->cookie_len) { | |
993 | memcpy(bufp, &session->cookie[0], session->cookie_len); | |
994 | bufp += session->cookie_len; | |
995 | } | |
996 | if (session->l2specific_len) { | |
997 | if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { | |
998 | u32 l2h = 0; | |
999 | if (session->send_seq) { | |
1000 | l2h = 0x40000000 | session->ns; | |
1001 | session->ns++; | |
1002 | session->ns &= 0xffffff; | |
a4ca44fa JP |
1003 | l2tp_dbg(session, L2TP_MSG_SEQ, |
1004 | "%s: updated ns to %u\n", | |
1005 | session->name, session->ns); | |
f7faffa3 JC |
1006 | } |
1007 | ||
1008 | *((__be32 *) bufp) = htonl(l2h); | |
1009 | } | |
1010 | bufp += session->l2specific_len; | |
1011 | } | |
1012 | if (session->offset) | |
1013 | bufp += session->offset; | |
fd558d18 | 1014 | |
f7faffa3 | 1015 | return bufp - optr; |
fd558d18 | 1016 | } |
fd558d18 | 1017 | |
fc130840 | 1018 | static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, |
d9d8da80 | 1019 | struct flowi *fl, size_t data_len) |
fd558d18 JC |
1020 | { |
1021 | struct l2tp_tunnel *tunnel = session->tunnel; | |
1022 | unsigned int len = skb->len; | |
1023 | int error; | |
5de7aee5 | 1024 | struct l2tp_stats *tstats, *sstats; |
fd558d18 JC |
1025 | |
1026 | /* Debug */ | |
1027 | if (session->send_seq) | |
a4ca44fa JP |
1028 | l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes, ns=%u\n", |
1029 | session->name, data_len, session->ns - 1); | |
fd558d18 | 1030 | else |
a4ca44fa JP |
1031 | l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes\n", |
1032 | session->name, data_len); | |
fd558d18 JC |
1033 | |
1034 | if (session->debug & L2TP_MSG_DATA) { | |
0d76751f JC |
1035 | int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; |
1036 | unsigned char *datap = skb->data + uhlen; | |
fd558d18 | 1037 | |
a4ca44fa JP |
1038 | pr_debug("%s: xmit\n", session->name); |
1039 | print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, | |
1040 | datap, min_t(size_t, 32, len - uhlen)); | |
fd558d18 JC |
1041 | } |
1042 | ||
1043 | /* Queue the packet to IP for output */ | |
4e15ed4d | 1044 | skb->local_df = 1; |
d2cf3361 BL |
1045 | #if IS_ENABLED(CONFIG_IPV6) |
1046 | if (skb->sk->sk_family == PF_INET6) | |
1047 | error = inet6_csk_xmit(skb, NULL); | |
1048 | else | |
1049 | #endif | |
1050 | error = ip_queue_xmit(skb, fl); | |
fd558d18 JC |
1051 | |
1052 | /* Update stats */ | |
5de7aee5 JC |
1053 | tstats = &tunnel->stats; |
1054 | u64_stats_update_begin(&tstats->syncp); | |
1055 | sstats = &session->stats; | |
1056 | u64_stats_update_begin(&sstats->syncp); | |
fd558d18 | 1057 | if (error >= 0) { |
5de7aee5 JC |
1058 | tstats->tx_packets++; |
1059 | tstats->tx_bytes += len; | |
1060 | sstats->tx_packets++; | |
1061 | sstats->tx_bytes += len; | |
fd558d18 | 1062 | } else { |
5de7aee5 JC |
1063 | tstats->tx_errors++; |
1064 | sstats->tx_errors++; | |
fd558d18 | 1065 | } |
5de7aee5 JC |
1066 | u64_stats_update_end(&tstats->syncp); |
1067 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
1068 | |
1069 | return 0; | |
1070 | } | |
fd558d18 JC |
1071 | |
1072 | /* Automatically called when the skb is freed. | |
1073 | */ | |
1074 | static void l2tp_sock_wfree(struct sk_buff *skb) | |
1075 | { | |
1076 | sock_put(skb->sk); | |
1077 | } | |
1078 | ||
1079 | /* For data skbs that we transmit, we associate with the tunnel socket | |
1080 | * but don't do accounting. | |
1081 | */ | |
1082 | static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk) | |
1083 | { | |
1084 | sock_hold(sk); | |
1085 | skb->sk = sk; | |
1086 | skb->destructor = l2tp_sock_wfree; | |
1087 | } | |
1088 | ||
d2cf3361 BL |
1089 | #if IS_ENABLED(CONFIG_IPV6) |
1090 | static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb, | |
1091 | int udp_len) | |
1092 | { | |
1093 | struct ipv6_pinfo *np = inet6_sk(sk); | |
1094 | struct udphdr *uh = udp_hdr(skb); | |
1095 | ||
1096 | if (!skb_dst(skb) || !skb_dst(skb)->dev || | |
1097 | !(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) { | |
1098 | __wsum csum = skb_checksum(skb, 0, udp_len, 0); | |
1099 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
1100 | uh->check = csum_ipv6_magic(&np->saddr, &np->daddr, udp_len, | |
1101 | IPPROTO_UDP, csum); | |
1102 | if (uh->check == 0) | |
1103 | uh->check = CSUM_MANGLED_0; | |
1104 | } else { | |
1105 | skb->ip_summed = CHECKSUM_PARTIAL; | |
1106 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
1107 | skb->csum_offset = offsetof(struct udphdr, check); | |
1108 | uh->check = ~csum_ipv6_magic(&np->saddr, &np->daddr, | |
1109 | udp_len, IPPROTO_UDP, 0); | |
1110 | } | |
1111 | } | |
1112 | #endif | |
1113 | ||
fd558d18 JC |
1114 | /* If caller requires the skb to have a ppp header, the header must be |
1115 | * inserted in the skb data before calling this function. | |
1116 | */ | |
1117 | int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) | |
1118 | { | |
1119 | int data_len = skb->len; | |
0d76751f JC |
1120 | struct l2tp_tunnel *tunnel = session->tunnel; |
1121 | struct sock *sk = tunnel->sock; | |
d9d8da80 | 1122 | struct flowi *fl; |
fd558d18 | 1123 | struct udphdr *uh; |
fd558d18 JC |
1124 | struct inet_sock *inet; |
1125 | __wsum csum; | |
1126 | int old_headroom; | |
1127 | int new_headroom; | |
1128 | int headroom; | |
0d76751f JC |
1129 | int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; |
1130 | int udp_len; | |
fd558d18 JC |
1131 | |
1132 | /* Check that there's enough headroom in the skb to insert IP, | |
1133 | * UDP and L2TP headers. If not enough, expand it to | |
1134 | * make room. Adjust truesize. | |
1135 | */ | |
1136 | headroom = NET_SKB_PAD + sizeof(struct iphdr) + | |
0d76751f | 1137 | uhlen + hdr_len; |
fd558d18 | 1138 | old_headroom = skb_headroom(skb); |
835acf5d ED |
1139 | if (skb_cow_head(skb, headroom)) { |
1140 | dev_kfree_skb(skb); | |
fd558d18 | 1141 | goto abort; |
835acf5d | 1142 | } |
fd558d18 JC |
1143 | |
1144 | new_headroom = skb_headroom(skb); | |
1145 | skb_orphan(skb); | |
1146 | skb->truesize += new_headroom - old_headroom; | |
1147 | ||
1148 | /* Setup L2TP header */ | |
f7faffa3 | 1149 | session->build_header(session, __skb_push(skb, hdr_len)); |
fd558d18 | 1150 | |
0d76751f | 1151 | /* Reset skb netfilter state */ |
fd558d18 JC |
1152 | memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); |
1153 | IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | | |
1154 | IPSKB_REROUTED); | |
1155 | nf_reset(skb); | |
1156 | ||
6af88da1 DM |
1157 | bh_lock_sock(sk); |
1158 | if (sock_owned_by_user(sk)) { | |
1159 | dev_kfree_skb(skb); | |
1160 | goto out_unlock; | |
1161 | } | |
1162 | ||
fd558d18 JC |
1163 | /* Get routing info from the tunnel socket */ |
1164 | skb_dst_drop(skb); | |
71b1391a | 1165 | skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0))); |
fd558d18 | 1166 | |
d9d8da80 DM |
1167 | inet = inet_sk(sk); |
1168 | fl = &inet->cork.fl; | |
0d76751f JC |
1169 | switch (tunnel->encap) { |
1170 | case L2TP_ENCAPTYPE_UDP: | |
1171 | /* Setup UDP header */ | |
0d76751f JC |
1172 | __skb_push(skb, sizeof(*uh)); |
1173 | skb_reset_transport_header(skb); | |
1174 | uh = udp_hdr(skb); | |
1175 | uh->source = inet->inet_sport; | |
1176 | uh->dest = inet->inet_dport; | |
1177 | udp_len = uhlen + hdr_len + data_len; | |
1178 | uh->len = htons(udp_len); | |
1179 | uh->check = 0; | |
1180 | ||
1181 | /* Calculate UDP checksum if configured to do so */ | |
d2cf3361 BL |
1182 | #if IS_ENABLED(CONFIG_IPV6) |
1183 | if (sk->sk_family == PF_INET6) | |
1184 | l2tp_xmit_ipv6_csum(sk, skb, udp_len); | |
1185 | else | |
1186 | #endif | |
0d76751f JC |
1187 | if (sk->sk_no_check == UDP_CSUM_NOXMIT) |
1188 | skb->ip_summed = CHECKSUM_NONE; | |
1189 | else if ((skb_dst(skb) && skb_dst(skb)->dev) && | |
1190 | (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) { | |
1191 | skb->ip_summed = CHECKSUM_COMPLETE; | |
1192 | csum = skb_checksum(skb, 0, udp_len, 0); | |
1193 | uh->check = csum_tcpudp_magic(inet->inet_saddr, | |
1194 | inet->inet_daddr, | |
1195 | udp_len, IPPROTO_UDP, csum); | |
1196 | if (uh->check == 0) | |
1197 | uh->check = CSUM_MANGLED_0; | |
1198 | } else { | |
1199 | skb->ip_summed = CHECKSUM_PARTIAL; | |
1200 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
1201 | skb->csum_offset = offsetof(struct udphdr, check); | |
1202 | uh->check = ~csum_tcpudp_magic(inet->inet_saddr, | |
1203 | inet->inet_daddr, | |
1204 | udp_len, IPPROTO_UDP, 0); | |
1205 | } | |
1206 | break; | |
1207 | ||
1208 | case L2TP_ENCAPTYPE_IP: | |
1209 | break; | |
fd558d18 JC |
1210 | } |
1211 | ||
0d76751f JC |
1212 | l2tp_skb_set_owner_w(skb, sk); |
1213 | ||
d9d8da80 | 1214 | l2tp_xmit_core(session, skb, fl, data_len); |
6af88da1 DM |
1215 | out_unlock: |
1216 | bh_unlock_sock(sk); | |
fd558d18 JC |
1217 | |
1218 | abort: | |
1219 | return 0; | |
1220 | } | |
1221 | EXPORT_SYMBOL_GPL(l2tp_xmit_skb); | |
1222 | ||
1223 | /***************************************************************************** | |
1224 | * Tinnel and session create/destroy. | |
1225 | *****************************************************************************/ | |
1226 | ||
1227 | /* Tunnel socket destruct hook. | |
1228 | * The tunnel context is deleted only when all session sockets have been | |
1229 | * closed. | |
1230 | */ | |
fc130840 | 1231 | static void l2tp_tunnel_destruct(struct sock *sk) |
fd558d18 JC |
1232 | { |
1233 | struct l2tp_tunnel *tunnel; | |
1234 | ||
1235 | tunnel = sk->sk_user_data; | |
1236 | if (tunnel == NULL) | |
1237 | goto end; | |
1238 | ||
a4ca44fa | 1239 | l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name); |
fd558d18 JC |
1240 | |
1241 | /* Close all sessions */ | |
1242 | l2tp_tunnel_closeall(tunnel); | |
1243 | ||
0d76751f JC |
1244 | switch (tunnel->encap) { |
1245 | case L2TP_ENCAPTYPE_UDP: | |
1246 | /* No longer an encapsulation socket. See net/ipv4/udp.c */ | |
1247 | (udp_sk(sk))->encap_type = 0; | |
1248 | (udp_sk(sk))->encap_rcv = NULL; | |
1249 | break; | |
1250 | case L2TP_ENCAPTYPE_IP: | |
1251 | break; | |
1252 | } | |
fd558d18 JC |
1253 | |
1254 | /* Remove hooks into tunnel socket */ | |
1255 | tunnel->sock = NULL; | |
1256 | sk->sk_destruct = tunnel->old_sk_destruct; | |
1257 | sk->sk_user_data = NULL; | |
1258 | ||
1259 | /* Call the original destructor */ | |
1260 | if (sk->sk_destruct) | |
1261 | (*sk->sk_destruct)(sk); | |
1262 | ||
1263 | /* We're finished with the socket */ | |
1264 | l2tp_tunnel_dec_refcount(tunnel); | |
1265 | ||
1266 | end: | |
1267 | return; | |
1268 | } | |
fd558d18 JC |
1269 | |
1270 | /* When the tunnel is closed, all the attached sessions need to go too. | |
1271 | */ | |
fc130840 | 1272 | static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) |
fd558d18 JC |
1273 | { |
1274 | int hash; | |
1275 | struct hlist_node *walk; | |
1276 | struct hlist_node *tmp; | |
1277 | struct l2tp_session *session; | |
1278 | ||
1279 | BUG_ON(tunnel == NULL); | |
1280 | ||
a4ca44fa JP |
1281 | l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n", |
1282 | tunnel->name); | |
fd558d18 JC |
1283 | |
1284 | write_lock_bh(&tunnel->hlist_lock); | |
1285 | for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { | |
1286 | again: | |
1287 | hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { | |
1288 | session = hlist_entry(walk, struct l2tp_session, hlist); | |
1289 | ||
a4ca44fa JP |
1290 | l2tp_info(session, L2TP_MSG_CONTROL, |
1291 | "%s: closing session\n", session->name); | |
fd558d18 JC |
1292 | |
1293 | hlist_del_init(&session->hlist); | |
1294 | ||
1295 | /* Since we should hold the sock lock while | |
1296 | * doing any unbinding, we need to release the | |
1297 | * lock we're holding before taking that lock. | |
1298 | * Hold a reference to the sock so it doesn't | |
1299 | * disappear as we're jumping between locks. | |
1300 | */ | |
1301 | if (session->ref != NULL) | |
1302 | (*session->ref)(session); | |
1303 | ||
1304 | write_unlock_bh(&tunnel->hlist_lock); | |
1305 | ||
f7faffa3 JC |
1306 | if (tunnel->version != L2TP_HDR_VER_2) { |
1307 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
1308 | ||
e02d494d JC |
1309 | spin_lock_bh(&pn->l2tp_session_hlist_lock); |
1310 | hlist_del_init_rcu(&session->global_hlist); | |
1311 | spin_unlock_bh(&pn->l2tp_session_hlist_lock); | |
1312 | synchronize_rcu(); | |
f7faffa3 JC |
1313 | } |
1314 | ||
fd558d18 JC |
1315 | if (session->session_close != NULL) |
1316 | (*session->session_close)(session); | |
1317 | ||
1318 | if (session->deref != NULL) | |
1319 | (*session->deref)(session); | |
1320 | ||
1321 | write_lock_bh(&tunnel->hlist_lock); | |
1322 | ||
1323 | /* Now restart from the beginning of this hash | |
1324 | * chain. We always remove a session from the | |
1325 | * list so we are guaranteed to make forward | |
1326 | * progress. | |
1327 | */ | |
1328 | goto again; | |
1329 | } | |
1330 | } | |
1331 | write_unlock_bh(&tunnel->hlist_lock); | |
1332 | } | |
fd558d18 JC |
1333 | |
1334 | /* Really kill the tunnel. | |
1335 | * Come here only when all sessions have been cleared from the tunnel. | |
1336 | */ | |
fc130840 | 1337 | static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) |
fd558d18 JC |
1338 | { |
1339 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
1340 | ||
1341 | BUG_ON(atomic_read(&tunnel->ref_count) != 0); | |
1342 | BUG_ON(tunnel->sock != NULL); | |
1343 | ||
a4ca44fa | 1344 | l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name); |
fd558d18 JC |
1345 | |
1346 | /* Remove from tunnel list */ | |
e02d494d JC |
1347 | spin_lock_bh(&pn->l2tp_tunnel_list_lock); |
1348 | list_del_rcu(&tunnel->list); | |
1349 | spin_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
1350 | synchronize_rcu(); | |
fd558d18 JC |
1351 | |
1352 | atomic_dec(&l2tp_tunnel_count); | |
1353 | kfree(tunnel); | |
1354 | } | |
fd558d18 | 1355 | |
789a4a2c JC |
1356 | /* Create a socket for the tunnel, if one isn't set up by |
1357 | * userspace. This is used for static tunnels where there is no | |
1358 | * managing L2TP daemon. | |
1359 | */ | |
1360 | static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp) | |
1361 | { | |
1362 | int err = -EINVAL; | |
1363 | struct sockaddr_in udp_addr; | |
f9bac8df CE |
1364 | #if IS_ENABLED(CONFIG_IPV6) |
1365 | struct sockaddr_in6 udp6_addr; | |
5dac94e1 | 1366 | struct sockaddr_l2tpip6 ip6_addr; |
f9bac8df | 1367 | #endif |
789a4a2c | 1368 | struct sockaddr_l2tpip ip_addr; |
7bddd0db | 1369 | struct socket *sock = NULL; |
789a4a2c JC |
1370 | |
1371 | switch (cfg->encap) { | |
1372 | case L2TP_ENCAPTYPE_UDP: | |
f9bac8df CE |
1373 | #if IS_ENABLED(CONFIG_IPV6) |
1374 | if (cfg->local_ip6 && cfg->peer_ip6) { | |
1375 | err = sock_create(AF_INET6, SOCK_DGRAM, 0, sockp); | |
1376 | if (err < 0) | |
1377 | goto out; | |
789a4a2c | 1378 | |
f9bac8df | 1379 | sock = *sockp; |
789a4a2c | 1380 | |
f9bac8df CE |
1381 | memset(&udp6_addr, 0, sizeof(udp6_addr)); |
1382 | udp6_addr.sin6_family = AF_INET6; | |
1383 | memcpy(&udp6_addr.sin6_addr, cfg->local_ip6, | |
1384 | sizeof(udp6_addr.sin6_addr)); | |
1385 | udp6_addr.sin6_port = htons(cfg->local_udp_port); | |
1386 | err = kernel_bind(sock, (struct sockaddr *) &udp6_addr, | |
1387 | sizeof(udp6_addr)); | |
1388 | if (err < 0) | |
1389 | goto out; | |
789a4a2c | 1390 | |
f9bac8df CE |
1391 | udp6_addr.sin6_family = AF_INET6; |
1392 | memcpy(&udp6_addr.sin6_addr, cfg->peer_ip6, | |
1393 | sizeof(udp6_addr.sin6_addr)); | |
1394 | udp6_addr.sin6_port = htons(cfg->peer_udp_port); | |
1395 | err = kernel_connect(sock, | |
1396 | (struct sockaddr *) &udp6_addr, | |
1397 | sizeof(udp6_addr), 0); | |
1398 | if (err < 0) | |
1399 | goto out; | |
1400 | } else | |
1401 | #endif | |
1402 | { | |
1403 | err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp); | |
1404 | if (err < 0) | |
1405 | goto out; | |
1406 | ||
1407 | sock = *sockp; | |
1408 | ||
1409 | memset(&udp_addr, 0, sizeof(udp_addr)); | |
1410 | udp_addr.sin_family = AF_INET; | |
1411 | udp_addr.sin_addr = cfg->local_ip; | |
1412 | udp_addr.sin_port = htons(cfg->local_udp_port); | |
1413 | err = kernel_bind(sock, (struct sockaddr *) &udp_addr, | |
1414 | sizeof(udp_addr)); | |
1415 | if (err < 0) | |
1416 | goto out; | |
1417 | ||
1418 | udp_addr.sin_family = AF_INET; | |
1419 | udp_addr.sin_addr = cfg->peer_ip; | |
1420 | udp_addr.sin_port = htons(cfg->peer_udp_port); | |
1421 | err = kernel_connect(sock, | |
1422 | (struct sockaddr *) &udp_addr, | |
1423 | sizeof(udp_addr), 0); | |
1424 | if (err < 0) | |
1425 | goto out; | |
1426 | } | |
789a4a2c JC |
1427 | |
1428 | if (!cfg->use_udp_checksums) | |
1429 | sock->sk->sk_no_check = UDP_CSUM_NOXMIT; | |
1430 | ||
1431 | break; | |
1432 | ||
1433 | case L2TP_ENCAPTYPE_IP: | |
f9bac8df CE |
1434 | #if IS_ENABLED(CONFIG_IPV6) |
1435 | if (cfg->local_ip6 && cfg->peer_ip6) { | |
5dac94e1 JC |
1436 | err = sock_create(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP, |
1437 | sockp); | |
1438 | if (err < 0) | |
1439 | goto out; | |
789a4a2c | 1440 | |
5dac94e1 | 1441 | sock = *sockp; |
789a4a2c | 1442 | |
5dac94e1 JC |
1443 | memset(&ip6_addr, 0, sizeof(ip6_addr)); |
1444 | ip6_addr.l2tp_family = AF_INET6; | |
1445 | memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6, | |
1446 | sizeof(ip6_addr.l2tp_addr)); | |
1447 | ip6_addr.l2tp_conn_id = tunnel_id; | |
1448 | err = kernel_bind(sock, (struct sockaddr *) &ip6_addr, | |
1449 | sizeof(ip6_addr)); | |
1450 | if (err < 0) | |
1451 | goto out; | |
789a4a2c | 1452 | |
5dac94e1 JC |
1453 | ip6_addr.l2tp_family = AF_INET6; |
1454 | memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6, | |
1455 | sizeof(ip6_addr.l2tp_addr)); | |
1456 | ip6_addr.l2tp_conn_id = peer_tunnel_id; | |
1457 | err = kernel_connect(sock, | |
1458 | (struct sockaddr *) &ip6_addr, | |
1459 | sizeof(ip6_addr), 0); | |
1460 | if (err < 0) | |
1461 | goto out; | |
1462 | } else | |
1463 | #endif | |
1464 | { | |
1465 | err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, | |
1466 | sockp); | |
1467 | if (err < 0) | |
1468 | goto out; | |
789a4a2c | 1469 | |
5dac94e1 JC |
1470 | sock = *sockp; |
1471 | ||
1472 | memset(&ip_addr, 0, sizeof(ip_addr)); | |
1473 | ip_addr.l2tp_family = AF_INET; | |
1474 | ip_addr.l2tp_addr = cfg->local_ip; | |
1475 | ip_addr.l2tp_conn_id = tunnel_id; | |
1476 | err = kernel_bind(sock, (struct sockaddr *) &ip_addr, | |
1477 | sizeof(ip_addr)); | |
1478 | if (err < 0) | |
1479 | goto out; | |
1480 | ||
1481 | ip_addr.l2tp_family = AF_INET; | |
1482 | ip_addr.l2tp_addr = cfg->peer_ip; | |
1483 | ip_addr.l2tp_conn_id = peer_tunnel_id; | |
1484 | err = kernel_connect(sock, (struct sockaddr *) &ip_addr, | |
1485 | sizeof(ip_addr), 0); | |
1486 | if (err < 0) | |
1487 | goto out; | |
1488 | } | |
789a4a2c JC |
1489 | break; |
1490 | ||
1491 | default: | |
1492 | goto out; | |
1493 | } | |
1494 | ||
1495 | out: | |
1496 | if ((err < 0) && sock) { | |
1497 | sock_release(sock); | |
1498 | *sockp = NULL; | |
1499 | } | |
1500 | ||
1501 | return err; | |
1502 | } | |
1503 | ||
fd558d18 JC |
1504 | int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp) |
1505 | { | |
1506 | struct l2tp_tunnel *tunnel = NULL; | |
1507 | int err; | |
1508 | struct socket *sock = NULL; | |
1509 | struct sock *sk = NULL; | |
1510 | struct l2tp_net *pn; | |
0d76751f | 1511 | enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; |
fd558d18 JC |
1512 | |
1513 | /* Get the tunnel socket from the fd, which was opened by | |
789a4a2c JC |
1514 | * the userspace L2TP daemon. If not specified, create a |
1515 | * kernel socket. | |
fd558d18 | 1516 | */ |
789a4a2c JC |
1517 | if (fd < 0) { |
1518 | err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock); | |
1519 | if (err < 0) | |
1520 | goto err; | |
1521 | } else { | |
1522 | err = -EBADF; | |
1523 | sock = sockfd_lookup(fd, &err); | |
1524 | if (!sock) { | |
a4ca44fa | 1525 | pr_err("tunl %hu: sockfd_lookup(fd=%d) returned %d\n", |
789a4a2c JC |
1526 | tunnel_id, fd, err); |
1527 | goto err; | |
1528 | } | |
fd558d18 JC |
1529 | } |
1530 | ||
1531 | sk = sock->sk; | |
1532 | ||
0d76751f JC |
1533 | if (cfg != NULL) |
1534 | encap = cfg->encap; | |
1535 | ||
fd558d18 | 1536 | /* Quick sanity checks */ |
0d76751f JC |
1537 | switch (encap) { |
1538 | case L2TP_ENCAPTYPE_UDP: | |
1539 | err = -EPROTONOSUPPORT; | |
1540 | if (sk->sk_protocol != IPPROTO_UDP) { | |
a4ca44fa | 1541 | pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n", |
0d76751f JC |
1542 | tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); |
1543 | goto err; | |
1544 | } | |
1545 | break; | |
1546 | case L2TP_ENCAPTYPE_IP: | |
1547 | err = -EPROTONOSUPPORT; | |
1548 | if (sk->sk_protocol != IPPROTO_L2TP) { | |
a4ca44fa | 1549 | pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n", |
0d76751f JC |
1550 | tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP); |
1551 | goto err; | |
1552 | } | |
1553 | break; | |
fd558d18 JC |
1554 | } |
1555 | ||
1556 | /* Check if this socket has already been prepped */ | |
1557 | tunnel = (struct l2tp_tunnel *)sk->sk_user_data; | |
1558 | if (tunnel != NULL) { | |
1559 | /* This socket has already been prepped */ | |
1560 | err = -EBUSY; | |
1561 | goto err; | |
1562 | } | |
1563 | ||
fd558d18 JC |
1564 | tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); |
1565 | if (tunnel == NULL) { | |
1566 | err = -ENOMEM; | |
1567 | goto err; | |
1568 | } | |
1569 | ||
1570 | tunnel->version = version; | |
1571 | tunnel->tunnel_id = tunnel_id; | |
1572 | tunnel->peer_tunnel_id = peer_tunnel_id; | |
1573 | tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; | |
1574 | ||
1575 | tunnel->magic = L2TP_TUNNEL_MAGIC; | |
1576 | sprintf(&tunnel->name[0], "tunl %u", tunnel_id); | |
1577 | rwlock_init(&tunnel->hlist_lock); | |
1578 | ||
1579 | /* The net we belong to */ | |
1580 | tunnel->l2tp_net = net; | |
1581 | pn = l2tp_pernet(net); | |
1582 | ||
0d76751f | 1583 | if (cfg != NULL) |
fd558d18 JC |
1584 | tunnel->debug = cfg->debug; |
1585 | ||
1586 | /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ | |
0d76751f JC |
1587 | tunnel->encap = encap; |
1588 | if (encap == L2TP_ENCAPTYPE_UDP) { | |
1589 | /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ | |
1590 | udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; | |
1591 | udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv; | |
d2cf3361 BL |
1592 | #if IS_ENABLED(CONFIG_IPV6) |
1593 | if (sk->sk_family == PF_INET6) | |
1594 | udpv6_encap_enable(); | |
1595 | else | |
1596 | #endif | |
447167bf | 1597 | udp_encap_enable(); |
0d76751f | 1598 | } |
fd558d18 JC |
1599 | |
1600 | sk->sk_user_data = tunnel; | |
1601 | ||
1602 | /* Hook on the tunnel socket destructor so that we can cleanup | |
1603 | * if the tunnel socket goes away. | |
1604 | */ | |
1605 | tunnel->old_sk_destruct = sk->sk_destruct; | |
1606 | sk->sk_destruct = &l2tp_tunnel_destruct; | |
1607 | tunnel->sock = sk; | |
1608 | sk->sk_allocation = GFP_ATOMIC; | |
1609 | ||
1610 | /* Add tunnel to our list */ | |
1611 | INIT_LIST_HEAD(&tunnel->list); | |
fd558d18 JC |
1612 | atomic_inc(&l2tp_tunnel_count); |
1613 | ||
1614 | /* Bump the reference count. The tunnel context is deleted | |
1769192a | 1615 | * only when this drops to zero. Must be done before list insertion |
fd558d18 JC |
1616 | */ |
1617 | l2tp_tunnel_inc_refcount(tunnel); | |
1769192a ED |
1618 | spin_lock_bh(&pn->l2tp_tunnel_list_lock); |
1619 | list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); | |
1620 | spin_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
fd558d18 JC |
1621 | |
1622 | err = 0; | |
1623 | err: | |
1624 | if (tunnelp) | |
1625 | *tunnelp = tunnel; | |
1626 | ||
789a4a2c JC |
1627 | /* If tunnel's socket was created by the kernel, it doesn't |
1628 | * have a file. | |
1629 | */ | |
1630 | if (sock && sock->file) | |
fd558d18 JC |
1631 | sockfd_put(sock); |
1632 | ||
1633 | return err; | |
1634 | } | |
1635 | EXPORT_SYMBOL_GPL(l2tp_tunnel_create); | |
1636 | ||
309795f4 JC |
1637 | /* This function is used by the netlink TUNNEL_DELETE command. |
1638 | */ | |
1639 | int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) | |
1640 | { | |
1641 | int err = 0; | |
789a4a2c | 1642 | struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL; |
309795f4 JC |
1643 | |
1644 | /* Force the tunnel socket to close. This will eventually | |
1645 | * cause the tunnel to be deleted via the normal socket close | |
1646 | * mechanisms when userspace closes the tunnel socket. | |
1647 | */ | |
789a4a2c JC |
1648 | if (sock != NULL) { |
1649 | err = inet_shutdown(sock, 2); | |
1650 | ||
1651 | /* If the tunnel's socket was created by the kernel, | |
1652 | * close the socket here since the socket was not | |
1653 | * created by userspace. | |
1654 | */ | |
1655 | if (sock->file == NULL) | |
1656 | err = inet_release(sock); | |
1657 | } | |
309795f4 JC |
1658 | |
1659 | return err; | |
1660 | } | |
1661 | EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); | |
1662 | ||
fd558d18 JC |
1663 | /* Really kill the session. |
1664 | */ | |
1665 | void l2tp_session_free(struct l2tp_session *session) | |
1666 | { | |
1667 | struct l2tp_tunnel *tunnel; | |
1668 | ||
1669 | BUG_ON(atomic_read(&session->ref_count) != 0); | |
1670 | ||
1671 | tunnel = session->tunnel; | |
1672 | if (tunnel != NULL) { | |
1673 | BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); | |
1674 | ||
1675 | /* Delete the session from the hash */ | |
1676 | write_lock_bh(&tunnel->hlist_lock); | |
1677 | hlist_del_init(&session->hlist); | |
1678 | write_unlock_bh(&tunnel->hlist_lock); | |
1679 | ||
f7faffa3 JC |
1680 | /* Unlink from the global hash if not L2TPv2 */ |
1681 | if (tunnel->version != L2TP_HDR_VER_2) { | |
1682 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
1683 | ||
e02d494d JC |
1684 | spin_lock_bh(&pn->l2tp_session_hlist_lock); |
1685 | hlist_del_init_rcu(&session->global_hlist); | |
1686 | spin_unlock_bh(&pn->l2tp_session_hlist_lock); | |
1687 | synchronize_rcu(); | |
f7faffa3 JC |
1688 | } |
1689 | ||
fd558d18 JC |
1690 | if (session->session_id != 0) |
1691 | atomic_dec(&l2tp_session_count); | |
1692 | ||
1693 | sock_put(tunnel->sock); | |
1694 | ||
1695 | /* This will delete the tunnel context if this | |
1696 | * is the last session on the tunnel. | |
1697 | */ | |
1698 | session->tunnel = NULL; | |
1699 | l2tp_tunnel_dec_refcount(tunnel); | |
1700 | } | |
1701 | ||
1702 | kfree(session); | |
1703 | ||
1704 | return; | |
1705 | } | |
1706 | EXPORT_SYMBOL_GPL(l2tp_session_free); | |
1707 | ||
309795f4 JC |
1708 | /* This function is used by the netlink SESSION_DELETE command and by |
1709 | pseudowire modules. | |
1710 | */ | |
1711 | int l2tp_session_delete(struct l2tp_session *session) | |
1712 | { | |
1713 | if (session->session_close != NULL) | |
1714 | (*session->session_close)(session); | |
1715 | ||
1716 | l2tp_session_dec_refcount(session); | |
1717 | ||
1718 | return 0; | |
1719 | } | |
1720 | EXPORT_SYMBOL_GPL(l2tp_session_delete); | |
1721 | ||
1722 | ||
f7faffa3 JC |
1723 | /* We come here whenever a session's send_seq, cookie_len or |
1724 | * l2specific_len parameters are set. | |
1725 | */ | |
fc130840 | 1726 | static void l2tp_session_set_header_len(struct l2tp_session *session, int version) |
f7faffa3 JC |
1727 | { |
1728 | if (version == L2TP_HDR_VER_2) { | |
1729 | session->hdr_len = 6; | |
1730 | if (session->send_seq) | |
1731 | session->hdr_len += 4; | |
1732 | } else { | |
0d76751f JC |
1733 | session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset; |
1734 | if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP) | |
1735 | session->hdr_len += 4; | |
f7faffa3 JC |
1736 | } |
1737 | ||
1738 | } | |
f7faffa3 | 1739 | |
fd558d18 JC |
1740 | struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) |
1741 | { | |
1742 | struct l2tp_session *session; | |
1743 | ||
1744 | session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); | |
1745 | if (session != NULL) { | |
1746 | session->magic = L2TP_SESSION_MAGIC; | |
1747 | session->tunnel = tunnel; | |
1748 | ||
1749 | session->session_id = session_id; | |
1750 | session->peer_session_id = peer_session_id; | |
d301e325 | 1751 | session->nr = 0; |
fd558d18 JC |
1752 | |
1753 | sprintf(&session->name[0], "sess %u/%u", | |
1754 | tunnel->tunnel_id, session->session_id); | |
1755 | ||
1756 | skb_queue_head_init(&session->reorder_q); | |
1757 | ||
1758 | INIT_HLIST_NODE(&session->hlist); | |
f7faffa3 | 1759 | INIT_HLIST_NODE(&session->global_hlist); |
fd558d18 JC |
1760 | |
1761 | /* Inherit debug options from tunnel */ | |
1762 | session->debug = tunnel->debug; | |
1763 | ||
1764 | if (cfg) { | |
f7faffa3 | 1765 | session->pwtype = cfg->pw_type; |
fd558d18 | 1766 | session->debug = cfg->debug; |
fd558d18 JC |
1767 | session->mtu = cfg->mtu; |
1768 | session->mru = cfg->mru; | |
1769 | session->send_seq = cfg->send_seq; | |
1770 | session->recv_seq = cfg->recv_seq; | |
1771 | session->lns_mode = cfg->lns_mode; | |
f7faffa3 JC |
1772 | session->reorder_timeout = cfg->reorder_timeout; |
1773 | session->offset = cfg->offset; | |
1774 | session->l2specific_type = cfg->l2specific_type; | |
1775 | session->l2specific_len = cfg->l2specific_len; | |
1776 | session->cookie_len = cfg->cookie_len; | |
1777 | memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); | |
1778 | session->peer_cookie_len = cfg->peer_cookie_len; | |
1779 | memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); | |
fd558d18 JC |
1780 | } |
1781 | ||
f7faffa3 JC |
1782 | if (tunnel->version == L2TP_HDR_VER_2) |
1783 | session->build_header = l2tp_build_l2tpv2_header; | |
1784 | else | |
1785 | session->build_header = l2tp_build_l2tpv3_header; | |
1786 | ||
1787 | l2tp_session_set_header_len(session, tunnel->version); | |
1788 | ||
fd558d18 JC |
1789 | /* Bump the reference count. The session context is deleted |
1790 | * only when this drops to zero. | |
1791 | */ | |
1792 | l2tp_session_inc_refcount(session); | |
1793 | l2tp_tunnel_inc_refcount(tunnel); | |
1794 | ||
1795 | /* Ensure tunnel socket isn't deleted */ | |
1796 | sock_hold(tunnel->sock); | |
1797 | ||
1798 | /* Add session to the tunnel's hash list */ | |
1799 | write_lock_bh(&tunnel->hlist_lock); | |
1800 | hlist_add_head(&session->hlist, | |
1801 | l2tp_session_id_hash(tunnel, session_id)); | |
1802 | write_unlock_bh(&tunnel->hlist_lock); | |
1803 | ||
f7faffa3 JC |
1804 | /* And to the global session list if L2TPv3 */ |
1805 | if (tunnel->version != L2TP_HDR_VER_2) { | |
1806 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
1807 | ||
e02d494d JC |
1808 | spin_lock_bh(&pn->l2tp_session_hlist_lock); |
1809 | hlist_add_head_rcu(&session->global_hlist, | |
1810 | l2tp_session_id_hash_2(pn, session_id)); | |
1811 | spin_unlock_bh(&pn->l2tp_session_hlist_lock); | |
f7faffa3 JC |
1812 | } |
1813 | ||
fd558d18 JC |
1814 | /* Ignore management session in session count value */ |
1815 | if (session->session_id != 0) | |
1816 | atomic_inc(&l2tp_session_count); | |
1817 | } | |
1818 | ||
1819 | return session; | |
1820 | } | |
1821 | EXPORT_SYMBOL_GPL(l2tp_session_create); | |
1822 | ||
1823 | /***************************************************************************** | |
1824 | * Init and cleanup | |
1825 | *****************************************************************************/ | |
1826 | ||
1827 | static __net_init int l2tp_init_net(struct net *net) | |
1828 | { | |
e773aaff | 1829 | struct l2tp_net *pn = net_generic(net, l2tp_net_id); |
f7faffa3 | 1830 | int hash; |
fd558d18 | 1831 | |
fd558d18 | 1832 | INIT_LIST_HEAD(&pn->l2tp_tunnel_list); |
e02d494d | 1833 | spin_lock_init(&pn->l2tp_tunnel_list_lock); |
fd558d18 | 1834 | |
f7faffa3 JC |
1835 | for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) |
1836 | INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]); | |
1837 | ||
e02d494d | 1838 | spin_lock_init(&pn->l2tp_session_hlist_lock); |
f7faffa3 | 1839 | |
fd558d18 | 1840 | return 0; |
fd558d18 JC |
1841 | } |
1842 | ||
1843 | static struct pernet_operations l2tp_net_ops = { | |
1844 | .init = l2tp_init_net, | |
fd558d18 JC |
1845 | .id = &l2tp_net_id, |
1846 | .size = sizeof(struct l2tp_net), | |
1847 | }; | |
1848 | ||
1849 | static int __init l2tp_init(void) | |
1850 | { | |
1851 | int rc = 0; | |
1852 | ||
1853 | rc = register_pernet_device(&l2tp_net_ops); | |
1854 | if (rc) | |
1855 | goto out; | |
1856 | ||
a4ca44fa | 1857 | pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION); |
fd558d18 JC |
1858 | |
1859 | out: | |
1860 | return rc; | |
1861 | } | |
1862 | ||
1863 | static void __exit l2tp_exit(void) | |
1864 | { | |
1865 | unregister_pernet_device(&l2tp_net_ops); | |
1866 | } | |
1867 | ||
1868 | module_init(l2tp_init); | |
1869 | module_exit(l2tp_exit); | |
1870 | ||
1871 | MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); | |
1872 | MODULE_DESCRIPTION("L2TP core"); | |
1873 | MODULE_LICENSE("GPL"); | |
1874 | MODULE_VERSION(L2TP_DRV_VERSION); | |
1875 |