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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 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/string.h> | |
23 | #include <linux/list.h> | |
e02d494d | 24 | #include <linux/rculist.h> |
fd558d18 JC |
25 | #include <linux/uaccess.h> |
26 | ||
27 | #include <linux/kernel.h> | |
28 | #include <linux/spinlock.h> | |
29 | #include <linux/kthread.h> | |
30 | #include <linux/sched.h> | |
31 | #include <linux/slab.h> | |
32 | #include <linux/errno.h> | |
33 | #include <linux/jiffies.h> | |
34 | ||
35 | #include <linux/netdevice.h> | |
36 | #include <linux/net.h> | |
37 | #include <linux/inetdevice.h> | |
38 | #include <linux/skbuff.h> | |
39 | #include <linux/init.h> | |
0d76751f | 40 | #include <linux/in.h> |
fd558d18 JC |
41 | #include <linux/ip.h> |
42 | #include <linux/udp.h> | |
0d76751f | 43 | #include <linux/l2tp.h> |
fd558d18 JC |
44 | #include <linux/hash.h> |
45 | #include <linux/sort.h> | |
46 | #include <linux/file.h> | |
47 | #include <linux/nsproxy.h> | |
48 | #include <net/net_namespace.h> | |
49 | #include <net/netns/generic.h> | |
50 | #include <net/dst.h> | |
51 | #include <net/ip.h> | |
52 | #include <net/udp.h> | |
309795f4 | 53 | #include <net/inet_common.h> |
fd558d18 | 54 | #include <net/xfrm.h> |
0d76751f | 55 | #include <net/protocol.h> |
d2cf3361 BL |
56 | #include <net/inet6_connection_sock.h> |
57 | #include <net/inet_ecn.h> | |
58 | #include <net/ip6_route.h> | |
d499bd2e | 59 | #include <net/ip6_checksum.h> |
fd558d18 JC |
60 | |
61 | #include <asm/byteorder.h> | |
60063497 | 62 | #include <linux/atomic.h> |
fd558d18 JC |
63 | |
64 | #include "l2tp_core.h" | |
65 | ||
66 | #define L2TP_DRV_VERSION "V2.0" | |
67 | ||
68 | /* L2TP header constants */ | |
69 | #define L2TP_HDRFLAG_T 0x8000 | |
70 | #define L2TP_HDRFLAG_L 0x4000 | |
71 | #define L2TP_HDRFLAG_S 0x0800 | |
72 | #define L2TP_HDRFLAG_O 0x0200 | |
73 | #define L2TP_HDRFLAG_P 0x0100 | |
74 | ||
75 | #define L2TP_HDR_VER_MASK 0x000F | |
76 | #define L2TP_HDR_VER_2 0x0002 | |
f7faffa3 | 77 | #define L2TP_HDR_VER_3 0x0003 |
fd558d18 JC |
78 | |
79 | /* L2TPv3 default L2-specific sublayer */ | |
80 | #define L2TP_SLFLAG_S 0x40000000 | |
81 | #define L2TP_SL_SEQ_MASK 0x00ffffff | |
82 | ||
83 | #define L2TP_HDR_SIZE_SEQ 10 | |
84 | #define L2TP_HDR_SIZE_NOSEQ 6 | |
85 | ||
86 | /* Default trace flags */ | |
87 | #define L2TP_DEFAULT_DEBUG_FLAGS 0 | |
88 | ||
89 | #define PRINTK(_mask, _type, _lvl, _fmt, args...) \ | |
90 | do { \ | |
91 | if ((_mask) & (_type)) \ | |
92 | printk(_lvl "L2TP: " _fmt, ##args); \ | |
93 | } while (0) | |
94 | ||
95 | /* Private data stored for received packets in the skb. | |
96 | */ | |
97 | struct l2tp_skb_cb { | |
f7faffa3 | 98 | u32 ns; |
fd558d18 JC |
99 | u16 has_seq; |
100 | u16 length; | |
101 | unsigned long expires; | |
102 | }; | |
103 | ||
104 | #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) | |
105 | ||
106 | static atomic_t l2tp_tunnel_count; | |
107 | static atomic_t l2tp_session_count; | |
108 | ||
109 | /* per-net private data for this module */ | |
110 | static unsigned int l2tp_net_id; | |
111 | struct l2tp_net { | |
112 | struct list_head l2tp_tunnel_list; | |
e02d494d | 113 | spinlock_t l2tp_tunnel_list_lock; |
f7faffa3 | 114 | struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2]; |
e02d494d | 115 | spinlock_t l2tp_session_hlist_lock; |
fd558d18 JC |
116 | }; |
117 | ||
fc130840 | 118 | static void l2tp_session_set_header_len(struct l2tp_session *session, int version); |
119 | static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); | |
120 | static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); | |
121 | ||
fd558d18 JC |
122 | static inline struct l2tp_net *l2tp_pernet(struct net *net) |
123 | { | |
124 | BUG_ON(!net); | |
125 | ||
126 | return net_generic(net, l2tp_net_id); | |
127 | } | |
128 | ||
fc130840 | 129 | |
130 | /* Tunnel reference counts. Incremented per session that is added to | |
131 | * the tunnel. | |
132 | */ | |
133 | static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel) | |
134 | { | |
135 | atomic_inc(&tunnel->ref_count); | |
136 | } | |
137 | ||
138 | static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel) | |
139 | { | |
140 | if (atomic_dec_and_test(&tunnel->ref_count)) | |
141 | l2tp_tunnel_free(tunnel); | |
142 | } | |
143 | #ifdef L2TP_REFCNT_DEBUG | |
144 | #define l2tp_tunnel_inc_refcount(_t) do { \ | |
145 | printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \ | |
146 | l2tp_tunnel_inc_refcount_1(_t); \ | |
147 | } while (0) | |
148 | #define l2tp_tunnel_dec_refcount(_t) do { \ | |
149 | printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \ | |
150 | l2tp_tunnel_dec_refcount_1(_t); \ | |
151 | } while (0) | |
152 | #else | |
153 | #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t) | |
154 | #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t) | |
155 | #endif | |
156 | ||
f7faffa3 JC |
157 | /* Session hash global list for L2TPv3. |
158 | * The session_id SHOULD be random according to RFC3931, but several | |
159 | * L2TP implementations use incrementing session_ids. So we do a real | |
160 | * hash on the session_id, rather than a simple bitmask. | |
161 | */ | |
162 | static inline struct hlist_head * | |
163 | l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id) | |
164 | { | |
165 | return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)]; | |
166 | ||
167 | } | |
168 | ||
169 | /* Lookup a session by id in the global session list | |
170 | */ | |
171 | static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id) | |
172 | { | |
173 | struct l2tp_net *pn = l2tp_pernet(net); | |
174 | struct hlist_head *session_list = | |
175 | l2tp_session_id_hash_2(pn, session_id); | |
176 | struct l2tp_session *session; | |
177 | struct hlist_node *walk; | |
178 | ||
e02d494d JC |
179 | rcu_read_lock_bh(); |
180 | hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) { | |
f7faffa3 | 181 | if (session->session_id == session_id) { |
e02d494d | 182 | rcu_read_unlock_bh(); |
f7faffa3 JC |
183 | return session; |
184 | } | |
185 | } | |
e02d494d | 186 | rcu_read_unlock_bh(); |
f7faffa3 JC |
187 | |
188 | return NULL; | |
189 | } | |
190 | ||
fd558d18 JC |
191 | /* Session hash list. |
192 | * The session_id SHOULD be random according to RFC2661, but several | |
193 | * L2TP implementations (Cisco and Microsoft) use incrementing | |
194 | * session_ids. So we do a real hash on the session_id, rather than a | |
195 | * simple bitmask. | |
196 | */ | |
197 | static inline struct hlist_head * | |
198 | l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) | |
199 | { | |
200 | return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; | |
201 | } | |
202 | ||
203 | /* Lookup a session by id | |
204 | */ | |
f7faffa3 | 205 | struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id) |
fd558d18 | 206 | { |
f7faffa3 | 207 | struct hlist_head *session_list; |
fd558d18 JC |
208 | struct l2tp_session *session; |
209 | struct hlist_node *walk; | |
210 | ||
f7faffa3 JC |
211 | /* In L2TPv3, session_ids are unique over all tunnels and we |
212 | * sometimes need to look them up before we know the | |
213 | * tunnel. | |
214 | */ | |
215 | if (tunnel == NULL) | |
216 | return l2tp_session_find_2(net, session_id); | |
217 | ||
218 | session_list = l2tp_session_id_hash(tunnel, session_id); | |
fd558d18 JC |
219 | read_lock_bh(&tunnel->hlist_lock); |
220 | hlist_for_each_entry(session, walk, session_list, hlist) { | |
221 | if (session->session_id == session_id) { | |
222 | read_unlock_bh(&tunnel->hlist_lock); | |
223 | return session; | |
224 | } | |
225 | } | |
226 | read_unlock_bh(&tunnel->hlist_lock); | |
227 | ||
228 | return NULL; | |
229 | } | |
230 | EXPORT_SYMBOL_GPL(l2tp_session_find); | |
231 | ||
232 | struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth) | |
233 | { | |
234 | int hash; | |
235 | struct hlist_node *walk; | |
236 | struct l2tp_session *session; | |
237 | int count = 0; | |
238 | ||
239 | read_lock_bh(&tunnel->hlist_lock); | |
240 | for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { | |
241 | hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) { | |
242 | if (++count > nth) { | |
243 | read_unlock_bh(&tunnel->hlist_lock); | |
244 | return session; | |
245 | } | |
246 | } | |
247 | } | |
248 | ||
249 | read_unlock_bh(&tunnel->hlist_lock); | |
250 | ||
251 | return NULL; | |
252 | } | |
253 | EXPORT_SYMBOL_GPL(l2tp_session_find_nth); | |
254 | ||
309795f4 JC |
255 | /* Lookup a session by interface name. |
256 | * This is very inefficient but is only used by management interfaces. | |
257 | */ | |
258 | struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname) | |
259 | { | |
260 | struct l2tp_net *pn = l2tp_pernet(net); | |
261 | int hash; | |
262 | struct hlist_node *walk; | |
263 | struct l2tp_session *session; | |
264 | ||
e02d494d | 265 | rcu_read_lock_bh(); |
309795f4 | 266 | for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) { |
e02d494d | 267 | hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) { |
309795f4 | 268 | if (!strcmp(session->ifname, ifname)) { |
e02d494d | 269 | rcu_read_unlock_bh(); |
309795f4 JC |
270 | return session; |
271 | } | |
272 | } | |
273 | } | |
274 | ||
e02d494d | 275 | rcu_read_unlock_bh(); |
309795f4 JC |
276 | |
277 | return NULL; | |
278 | } | |
279 | EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname); | |
280 | ||
fd558d18 JC |
281 | /* Lookup a tunnel by id |
282 | */ | |
283 | struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id) | |
284 | { | |
285 | struct l2tp_tunnel *tunnel; | |
286 | struct l2tp_net *pn = l2tp_pernet(net); | |
287 | ||
e02d494d JC |
288 | rcu_read_lock_bh(); |
289 | list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { | |
fd558d18 | 290 | if (tunnel->tunnel_id == tunnel_id) { |
e02d494d | 291 | rcu_read_unlock_bh(); |
fd558d18 JC |
292 | return tunnel; |
293 | } | |
294 | } | |
e02d494d | 295 | rcu_read_unlock_bh(); |
fd558d18 JC |
296 | |
297 | return NULL; | |
298 | } | |
299 | EXPORT_SYMBOL_GPL(l2tp_tunnel_find); | |
300 | ||
301 | struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth) | |
302 | { | |
303 | struct l2tp_net *pn = l2tp_pernet(net); | |
304 | struct l2tp_tunnel *tunnel; | |
305 | int count = 0; | |
306 | ||
e02d494d JC |
307 | rcu_read_lock_bh(); |
308 | list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { | |
fd558d18 | 309 | if (++count > nth) { |
e02d494d | 310 | rcu_read_unlock_bh(); |
fd558d18 JC |
311 | return tunnel; |
312 | } | |
313 | } | |
314 | ||
e02d494d | 315 | rcu_read_unlock_bh(); |
fd558d18 JC |
316 | |
317 | return NULL; | |
318 | } | |
319 | EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); | |
320 | ||
321 | /***************************************************************************** | |
322 | * Receive data handling | |
323 | *****************************************************************************/ | |
324 | ||
325 | /* Queue a skb in order. We come here only if the skb has an L2TP sequence | |
326 | * number. | |
327 | */ | |
328 | static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) | |
329 | { | |
330 | struct sk_buff *skbp; | |
331 | struct sk_buff *tmp; | |
f7faffa3 | 332 | u32 ns = L2TP_SKB_CB(skb)->ns; |
5de7aee5 | 333 | struct l2tp_stats *sstats; |
fd558d18 JC |
334 | |
335 | spin_lock_bh(&session->reorder_q.lock); | |
5de7aee5 | 336 | sstats = &session->stats; |
fd558d18 JC |
337 | skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { |
338 | if (L2TP_SKB_CB(skbp)->ns > ns) { | |
339 | __skb_queue_before(&session->reorder_q, skbp, skb); | |
340 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
341 | "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", | |
342 | session->name, ns, L2TP_SKB_CB(skbp)->ns, | |
343 | skb_queue_len(&session->reorder_q)); | |
5de7aee5 JC |
344 | u64_stats_update_begin(&sstats->syncp); |
345 | sstats->rx_oos_packets++; | |
346 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
347 | goto out; |
348 | } | |
349 | } | |
350 | ||
351 | __skb_queue_tail(&session->reorder_q, skb); | |
352 | ||
353 | out: | |
354 | spin_unlock_bh(&session->reorder_q.lock); | |
355 | } | |
356 | ||
357 | /* Dequeue a single skb. | |
358 | */ | |
359 | static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) | |
360 | { | |
361 | struct l2tp_tunnel *tunnel = session->tunnel; | |
362 | int length = L2TP_SKB_CB(skb)->length; | |
5de7aee5 | 363 | struct l2tp_stats *tstats, *sstats; |
fd558d18 JC |
364 | |
365 | /* We're about to requeue the skb, so return resources | |
366 | * to its current owner (a socket receive buffer). | |
367 | */ | |
368 | skb_orphan(skb); | |
369 | ||
5de7aee5 JC |
370 | tstats = &tunnel->stats; |
371 | u64_stats_update_begin(&tstats->syncp); | |
372 | sstats = &session->stats; | |
373 | u64_stats_update_begin(&sstats->syncp); | |
374 | tstats->rx_packets++; | |
375 | tstats->rx_bytes += length; | |
376 | sstats->rx_packets++; | |
377 | sstats->rx_bytes += length; | |
378 | u64_stats_update_end(&tstats->syncp); | |
379 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
380 | |
381 | if (L2TP_SKB_CB(skb)->has_seq) { | |
382 | /* Bump our Nr */ | |
383 | session->nr++; | |
f7faffa3 JC |
384 | if (tunnel->version == L2TP_HDR_VER_2) |
385 | session->nr &= 0xffff; | |
386 | else | |
387 | session->nr &= 0xffffff; | |
388 | ||
fd558d18 JC |
389 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
390 | "%s: updated nr to %hu\n", session->name, session->nr); | |
391 | } | |
392 | ||
393 | /* call private receive handler */ | |
394 | if (session->recv_skb != NULL) | |
395 | (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); | |
396 | else | |
397 | kfree_skb(skb); | |
398 | ||
399 | if (session->deref) | |
400 | (*session->deref)(session); | |
401 | } | |
402 | ||
403 | /* Dequeue skbs from the session's reorder_q, subject to packet order. | |
404 | * Skbs that have been in the queue for too long are simply discarded. | |
405 | */ | |
406 | static void l2tp_recv_dequeue(struct l2tp_session *session) | |
407 | { | |
408 | struct sk_buff *skb; | |
409 | struct sk_buff *tmp; | |
5de7aee5 | 410 | struct l2tp_stats *sstats; |
fd558d18 JC |
411 | |
412 | /* If the pkt at the head of the queue has the nr that we | |
413 | * expect to send up next, dequeue it and any other | |
414 | * in-sequence packets behind it. | |
415 | */ | |
e2e210c0 | 416 | start: |
fd558d18 | 417 | spin_lock_bh(&session->reorder_q.lock); |
5de7aee5 | 418 | sstats = &session->stats; |
fd558d18 JC |
419 | skb_queue_walk_safe(&session->reorder_q, skb, tmp) { |
420 | if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { | |
5de7aee5 JC |
421 | u64_stats_update_begin(&sstats->syncp); |
422 | sstats->rx_seq_discards++; | |
423 | sstats->rx_errors++; | |
424 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 | 425 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
f7faffa3 JC |
426 | "%s: oos pkt %u len %d discarded (too old), " |
427 | "waiting for %u, reorder_q_len=%d\n", | |
fd558d18 JC |
428 | session->name, L2TP_SKB_CB(skb)->ns, |
429 | L2TP_SKB_CB(skb)->length, session->nr, | |
430 | skb_queue_len(&session->reorder_q)); | |
431 | __skb_unlink(skb, &session->reorder_q); | |
432 | kfree_skb(skb); | |
433 | if (session->deref) | |
434 | (*session->deref)(session); | |
435 | continue; | |
436 | } | |
437 | ||
438 | if (L2TP_SKB_CB(skb)->has_seq) { | |
439 | if (L2TP_SKB_CB(skb)->ns != session->nr) { | |
440 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
f7faffa3 JC |
441 | "%s: holding oos pkt %u len %d, " |
442 | "waiting for %u, reorder_q_len=%d\n", | |
fd558d18 JC |
443 | session->name, L2TP_SKB_CB(skb)->ns, |
444 | L2TP_SKB_CB(skb)->length, session->nr, | |
445 | skb_queue_len(&session->reorder_q)); | |
446 | goto out; | |
447 | } | |
448 | } | |
449 | __skb_unlink(skb, &session->reorder_q); | |
450 | ||
451 | /* Process the skb. We release the queue lock while we | |
452 | * do so to let other contexts process the queue. | |
453 | */ | |
454 | spin_unlock_bh(&session->reorder_q.lock); | |
455 | l2tp_recv_dequeue_skb(session, skb); | |
e2e210c0 | 456 | goto start; |
fd558d18 JC |
457 | } |
458 | ||
459 | out: | |
460 | spin_unlock_bh(&session->reorder_q.lock); | |
461 | } | |
462 | ||
463 | static inline int l2tp_verify_udp_checksum(struct sock *sk, | |
464 | struct sk_buff *skb) | |
465 | { | |
466 | struct udphdr *uh = udp_hdr(skb); | |
467 | u16 ulen = ntohs(uh->len); | |
fd558d18 JC |
468 | __wsum psum; |
469 | ||
d2cf3361 | 470 | if (sk->sk_no_check || skb_csum_unnecessary(skb)) |
fd558d18 JC |
471 | return 0; |
472 | ||
d2cf3361 BL |
473 | #if IS_ENABLED(CONFIG_IPV6) |
474 | if (sk->sk_family == PF_INET6) { | |
475 | if (!uh->check) { | |
476 | LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n"); | |
477 | return 1; | |
478 | } | |
479 | if ((skb->ip_summed == CHECKSUM_COMPLETE) && | |
480 | !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, | |
481 | &ipv6_hdr(skb)->daddr, ulen, | |
482 | IPPROTO_UDP, skb->csum)) { | |
483 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
484 | return 0; | |
485 | } | |
486 | skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr, | |
487 | &ipv6_hdr(skb)->daddr, | |
488 | skb->len, IPPROTO_UDP, | |
489 | 0)); | |
490 | } else | |
491 | #endif | |
492 | { | |
493 | struct inet_sock *inet; | |
494 | if (!uh->check) | |
495 | return 0; | |
496 | inet = inet_sk(sk); | |
497 | psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, | |
498 | ulen, IPPROTO_UDP, 0); | |
499 | ||
500 | if ((skb->ip_summed == CHECKSUM_COMPLETE) && | |
501 | !csum_fold(csum_add(psum, skb->csum))) | |
502 | return 0; | |
503 | skb->csum = psum; | |
504 | } | |
fd558d18 JC |
505 | |
506 | return __skb_checksum_complete(skb); | |
507 | } | |
508 | ||
f7faffa3 JC |
509 | /* Do receive processing of L2TP data frames. We handle both L2TPv2 |
510 | * and L2TPv3 data frames here. | |
511 | * | |
512 | * L2TPv2 Data Message Header | |
513 | * | |
514 | * 0 1 2 3 | |
515 | * 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 | |
516 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
517 | * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | | |
518 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
519 | * | Tunnel ID | Session ID | | |
520 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
521 | * | Ns (opt) | Nr (opt) | | |
522 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
523 | * | Offset Size (opt) | Offset pad... (opt) | |
524 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
525 | * | |
526 | * Data frames are marked by T=0. All other fields are the same as | |
527 | * those in L2TP control frames. | |
528 | * | |
529 | * L2TPv3 Data Message Header | |
530 | * | |
531 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
532 | * | L2TP Session Header | | |
533 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
534 | * | L2-Specific Sublayer | | |
535 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
536 | * | Tunnel Payload ... | |
537 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
538 | * | |
539 | * L2TPv3 Session Header Over IP | |
540 | * | |
541 | * 0 1 2 3 | |
542 | * 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 | |
543 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
544 | * | Session ID | | |
545 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
546 | * | Cookie (optional, maximum 64 bits)... | |
547 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
548 | * | | |
549 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
550 | * | |
551 | * L2TPv3 L2-Specific Sublayer Format | |
552 | * | |
553 | * 0 1 2 3 | |
554 | * 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 | |
555 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
556 | * |x|S|x|x|x|x|x|x| Sequence Number | | |
557 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
558 | * | |
559 | * Cookie value, sublayer format and offset (pad) are negotiated with | |
560 | * the peer when the session is set up. Unlike L2TPv2, we do not need | |
561 | * to parse the packet header to determine if optional fields are | |
562 | * present. | |
563 | * | |
564 | * Caller must already have parsed the frame and determined that it is | |
565 | * a data (not control) frame before coming here. Fields up to the | |
566 | * session-id have already been parsed and ptr points to the data | |
567 | * after the session-id. | |
fd558d18 | 568 | */ |
f7faffa3 JC |
569 | void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, |
570 | unsigned char *ptr, unsigned char *optr, u16 hdrflags, | |
571 | int length, int (*payload_hook)(struct sk_buff *skb)) | |
fd558d18 | 572 | { |
f7faffa3 | 573 | struct l2tp_tunnel *tunnel = session->tunnel; |
fd558d18 | 574 | int offset; |
f7faffa3 | 575 | u32 ns, nr; |
5de7aee5 | 576 | struct l2tp_stats *sstats = &session->stats; |
fd558d18 JC |
577 | |
578 | /* The ref count is increased since we now hold a pointer to | |
579 | * the session. Take care to decrement the refcnt when exiting | |
580 | * this function from now on... | |
581 | */ | |
582 | l2tp_session_inc_refcount(session); | |
583 | if (session->ref) | |
584 | (*session->ref)(session); | |
585 | ||
f7faffa3 JC |
586 | /* Parse and check optional cookie */ |
587 | if (session->peer_cookie_len > 0) { | |
588 | if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { | |
589 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, | |
590 | "%s: cookie mismatch (%u/%u). Discarding.\n", | |
591 | tunnel->name, tunnel->tunnel_id, session->session_id); | |
5de7aee5 JC |
592 | u64_stats_update_begin(&sstats->syncp); |
593 | sstats->rx_cookie_discards++; | |
594 | u64_stats_update_end(&sstats->syncp); | |
f7faffa3 JC |
595 | goto discard; |
596 | } | |
597 | ptr += session->peer_cookie_len; | |
598 | } | |
599 | ||
fd558d18 JC |
600 | /* Handle the optional sequence numbers. Sequence numbers are |
601 | * in different places for L2TPv2 and L2TPv3. | |
602 | * | |
603 | * If we are the LAC, enable/disable sequence numbers under | |
604 | * the control of the LNS. If no sequence numbers present but | |
605 | * we were expecting them, discard frame. | |
606 | */ | |
607 | ns = nr = 0; | |
608 | L2TP_SKB_CB(skb)->has_seq = 0; | |
f7faffa3 JC |
609 | if (tunnel->version == L2TP_HDR_VER_2) { |
610 | if (hdrflags & L2TP_HDRFLAG_S) { | |
611 | ns = ntohs(*(__be16 *) ptr); | |
612 | ptr += 2; | |
613 | nr = ntohs(*(__be16 *) ptr); | |
614 | ptr += 2; | |
fd558d18 | 615 | |
f7faffa3 JC |
616 | /* Store L2TP info in the skb */ |
617 | L2TP_SKB_CB(skb)->ns = ns; | |
618 | L2TP_SKB_CB(skb)->has_seq = 1; | |
fd558d18 | 619 | |
f7faffa3 JC |
620 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
621 | "%s: recv data ns=%u, nr=%u, session nr=%u\n", | |
622 | session->name, ns, nr, session->nr); | |
623 | } | |
624 | } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { | |
625 | u32 l2h = ntohl(*(__be32 *) ptr); | |
626 | ||
627 | if (l2h & 0x40000000) { | |
628 | ns = l2h & 0x00ffffff; | |
629 | ||
630 | /* Store L2TP info in the skb */ | |
631 | L2TP_SKB_CB(skb)->ns = ns; | |
632 | L2TP_SKB_CB(skb)->has_seq = 1; | |
633 | ||
634 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
635 | "%s: recv data ns=%u, session nr=%u\n", | |
636 | session->name, ns, session->nr); | |
637 | } | |
fd558d18 JC |
638 | } |
639 | ||
f7faffa3 JC |
640 | /* Advance past L2-specific header, if present */ |
641 | ptr += session->l2specific_len; | |
642 | ||
fd558d18 JC |
643 | if (L2TP_SKB_CB(skb)->has_seq) { |
644 | /* Received a packet with sequence numbers. If we're the LNS, | |
645 | * check if we sre sending sequence numbers and if not, | |
646 | * configure it so. | |
647 | */ | |
648 | if ((!session->lns_mode) && (!session->send_seq)) { | |
649 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, | |
650 | "%s: requested to enable seq numbers by LNS\n", | |
651 | session->name); | |
652 | session->send_seq = -1; | |
f7faffa3 | 653 | l2tp_session_set_header_len(session, tunnel->version); |
fd558d18 JC |
654 | } |
655 | } else { | |
656 | /* No sequence numbers. | |
657 | * If user has configured mandatory sequence numbers, discard. | |
658 | */ | |
659 | if (session->recv_seq) { | |
660 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, | |
661 | "%s: recv data has no seq numbers when required. " | |
662 | "Discarding\n", session->name); | |
5de7aee5 JC |
663 | u64_stats_update_begin(&sstats->syncp); |
664 | sstats->rx_seq_discards++; | |
665 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
666 | goto discard; |
667 | } | |
668 | ||
669 | /* If we're the LAC and we're sending sequence numbers, the | |
670 | * LNS has requested that we no longer send sequence numbers. | |
671 | * If we're the LNS and we're sending sequence numbers, the | |
672 | * LAC is broken. Discard the frame. | |
673 | */ | |
674 | if ((!session->lns_mode) && (session->send_seq)) { | |
675 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, | |
676 | "%s: requested to disable seq numbers by LNS\n", | |
677 | session->name); | |
678 | session->send_seq = 0; | |
f7faffa3 | 679 | l2tp_session_set_header_len(session, tunnel->version); |
fd558d18 JC |
680 | } else if (session->send_seq) { |
681 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, | |
682 | "%s: recv data has no seq numbers when required. " | |
683 | "Discarding\n", session->name); | |
5de7aee5 JC |
684 | u64_stats_update_begin(&sstats->syncp); |
685 | sstats->rx_seq_discards++; | |
686 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
687 | goto discard; |
688 | } | |
689 | } | |
690 | ||
f7faffa3 JC |
691 | /* Session data offset is handled differently for L2TPv2 and |
692 | * L2TPv3. For L2TPv2, there is an optional 16-bit value in | |
693 | * the header. For L2TPv3, the offset is negotiated using AVPs | |
694 | * in the session setup control protocol. | |
695 | */ | |
696 | if (tunnel->version == L2TP_HDR_VER_2) { | |
697 | /* If offset bit set, skip it. */ | |
698 | if (hdrflags & L2TP_HDRFLAG_O) { | |
699 | offset = ntohs(*(__be16 *)ptr); | |
700 | ptr += 2 + offset; | |
701 | } | |
702 | } else | |
703 | ptr += session->offset; | |
fd558d18 JC |
704 | |
705 | offset = ptr - optr; | |
706 | if (!pskb_may_pull(skb, offset)) | |
707 | goto discard; | |
708 | ||
709 | __skb_pull(skb, offset); | |
710 | ||
711 | /* If caller wants to process the payload before we queue the | |
712 | * packet, do so now. | |
713 | */ | |
714 | if (payload_hook) | |
715 | if ((*payload_hook)(skb)) | |
716 | goto discard; | |
717 | ||
718 | /* Prepare skb for adding to the session's reorder_q. Hold | |
719 | * packets for max reorder_timeout or 1 second if not | |
720 | * reordering. | |
721 | */ | |
722 | L2TP_SKB_CB(skb)->length = length; | |
723 | L2TP_SKB_CB(skb)->expires = jiffies + | |
724 | (session->reorder_timeout ? session->reorder_timeout : HZ); | |
725 | ||
726 | /* Add packet to the session's receive queue. Reordering is done here, if | |
727 | * enabled. Saved L2TP protocol info is stored in skb->sb[]. | |
728 | */ | |
729 | if (L2TP_SKB_CB(skb)->has_seq) { | |
730 | if (session->reorder_timeout != 0) { | |
731 | /* Packet reordering enabled. Add skb to session's | |
732 | * reorder queue, in order of ns. | |
733 | */ | |
734 | l2tp_recv_queue_skb(session, skb); | |
735 | } else { | |
736 | /* Packet reordering disabled. Discard out-of-sequence | |
737 | * packets | |
738 | */ | |
739 | if (L2TP_SKB_CB(skb)->ns != session->nr) { | |
5de7aee5 JC |
740 | u64_stats_update_begin(&sstats->syncp); |
741 | sstats->rx_seq_discards++; | |
742 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 | 743 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
f7faffa3 JC |
744 | "%s: oos pkt %u len %d discarded, " |
745 | "waiting for %u, reorder_q_len=%d\n", | |
fd558d18 JC |
746 | session->name, L2TP_SKB_CB(skb)->ns, |
747 | L2TP_SKB_CB(skb)->length, session->nr, | |
748 | skb_queue_len(&session->reorder_q)); | |
749 | goto discard; | |
750 | } | |
751 | skb_queue_tail(&session->reorder_q, skb); | |
752 | } | |
753 | } else { | |
754 | /* No sequence numbers. Add the skb to the tail of the | |
755 | * reorder queue. This ensures that it will be | |
756 | * delivered after all previous sequenced skbs. | |
757 | */ | |
758 | skb_queue_tail(&session->reorder_q, skb); | |
759 | } | |
760 | ||
761 | /* Try to dequeue as many skbs from reorder_q as we can. */ | |
762 | l2tp_recv_dequeue(session); | |
763 | ||
764 | l2tp_session_dec_refcount(session); | |
765 | ||
f7faffa3 | 766 | return; |
fd558d18 JC |
767 | |
768 | discard: | |
5de7aee5 JC |
769 | u64_stats_update_begin(&sstats->syncp); |
770 | sstats->rx_errors++; | |
771 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
772 | kfree_skb(skb); |
773 | ||
774 | if (session->deref) | |
775 | (*session->deref)(session); | |
776 | ||
777 | l2tp_session_dec_refcount(session); | |
f7faffa3 JC |
778 | } |
779 | EXPORT_SYMBOL(l2tp_recv_common); | |
780 | ||
781 | /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame | |
782 | * here. The skb is not on a list when we get here. | |
783 | * Returns 0 if the packet was a data packet and was successfully passed on. | |
784 | * Returns 1 if the packet was not a good data packet and could not be | |
785 | * forwarded. All such packets are passed up to userspace to deal with. | |
786 | */ | |
fc130840 | 787 | static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, |
788 | int (*payload_hook)(struct sk_buff *skb)) | |
f7faffa3 JC |
789 | { |
790 | struct l2tp_session *session = NULL; | |
791 | unsigned char *ptr, *optr; | |
792 | u16 hdrflags; | |
793 | u32 tunnel_id, session_id; | |
794 | int offset; | |
795 | u16 version; | |
796 | int length; | |
5de7aee5 | 797 | struct l2tp_stats *tstats; |
f7faffa3 JC |
798 | |
799 | if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb)) | |
800 | goto discard_bad_csum; | |
801 | ||
802 | /* UDP always verifies the packet length. */ | |
803 | __skb_pull(skb, sizeof(struct udphdr)); | |
804 | ||
805 | /* Short packet? */ | |
806 | if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { | |
807 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, | |
808 | "%s: recv short packet (len=%d)\n", tunnel->name, skb->len); | |
809 | goto error; | |
810 | } | |
811 | ||
f7faffa3 JC |
812 | /* Trace packet contents, if enabled */ |
813 | if (tunnel->debug & L2TP_MSG_DATA) { | |
814 | length = min(32u, skb->len); | |
815 | if (!pskb_may_pull(skb, length)) | |
816 | goto error; | |
817 | ||
818 | printk(KERN_DEBUG "%s: recv: ", tunnel->name); | |
819 | ||
820 | offset = 0; | |
821 | do { | |
e50e705c | 822 | printk(" %02X", skb->data[offset]); |
f7faffa3 JC |
823 | } while (++offset < length); |
824 | ||
825 | printk("\n"); | |
826 | } | |
827 | ||
e50e705c ED |
828 | /* Point to L2TP header */ |
829 | optr = ptr = skb->data; | |
830 | ||
f7faffa3 JC |
831 | /* Get L2TP header flags */ |
832 | hdrflags = ntohs(*(__be16 *) ptr); | |
833 | ||
834 | /* Check protocol version */ | |
835 | version = hdrflags & L2TP_HDR_VER_MASK; | |
836 | if (version != tunnel->version) { | |
837 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, | |
838 | "%s: recv protocol version mismatch: got %d expected %d\n", | |
839 | tunnel->name, version, tunnel->version); | |
840 | goto error; | |
841 | } | |
842 | ||
843 | /* Get length of L2TP packet */ | |
844 | length = skb->len; | |
845 | ||
846 | /* If type is control packet, it is handled by userspace. */ | |
847 | if (hdrflags & L2TP_HDRFLAG_T) { | |
848 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, | |
849 | "%s: recv control packet, len=%d\n", tunnel->name, length); | |
850 | goto error; | |
851 | } | |
852 | ||
853 | /* Skip flags */ | |
854 | ptr += 2; | |
855 | ||
856 | if (tunnel->version == L2TP_HDR_VER_2) { | |
857 | /* If length is present, skip it */ | |
858 | if (hdrflags & L2TP_HDRFLAG_L) | |
859 | ptr += 2; | |
860 | ||
861 | /* Extract tunnel and session ID */ | |
862 | tunnel_id = ntohs(*(__be16 *) ptr); | |
863 | ptr += 2; | |
864 | session_id = ntohs(*(__be16 *) ptr); | |
865 | ptr += 2; | |
866 | } else { | |
867 | ptr += 2; /* skip reserved bits */ | |
868 | tunnel_id = tunnel->tunnel_id; | |
869 | session_id = ntohl(*(__be32 *) ptr); | |
870 | ptr += 4; | |
871 | } | |
872 | ||
873 | /* Find the session context */ | |
874 | session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id); | |
309795f4 | 875 | if (!session || !session->recv_skb) { |
f7faffa3 JC |
876 | /* Not found? Pass to userspace to deal with */ |
877 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, | |
878 | "%s: no session found (%u/%u). Passing up.\n", | |
879 | tunnel->name, tunnel_id, session_id); | |
880 | goto error; | |
881 | } | |
882 | ||
883 | l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); | |
fd558d18 JC |
884 | |
885 | return 0; | |
886 | ||
887 | discard_bad_csum: | |
888 | LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); | |
889 | UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0); | |
5de7aee5 JC |
890 | tstats = &tunnel->stats; |
891 | u64_stats_update_begin(&tstats->syncp); | |
892 | tstats->rx_errors++; | |
893 | u64_stats_update_end(&tstats->syncp); | |
fd558d18 JC |
894 | kfree_skb(skb); |
895 | ||
896 | return 0; | |
897 | ||
898 | error: | |
899 | /* Put UDP header back */ | |
900 | __skb_push(skb, sizeof(struct udphdr)); | |
901 | ||
902 | return 1; | |
903 | } | |
fd558d18 JC |
904 | |
905 | /* UDP encapsulation receive handler. See net/ipv4/udp.c. | |
906 | * Return codes: | |
907 | * 0 : success. | |
908 | * <0: error | |
909 | * >0: skb should be passed up to userspace as UDP. | |
910 | */ | |
911 | int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) | |
912 | { | |
913 | struct l2tp_tunnel *tunnel; | |
914 | ||
915 | tunnel = l2tp_sock_to_tunnel(sk); | |
916 | if (tunnel == NULL) | |
917 | goto pass_up; | |
918 | ||
919 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, | |
920 | "%s: received %d bytes\n", tunnel->name, skb->len); | |
921 | ||
922 | if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) | |
923 | goto pass_up_put; | |
924 | ||
925 | sock_put(sk); | |
926 | return 0; | |
927 | ||
928 | pass_up_put: | |
929 | sock_put(sk); | |
930 | pass_up: | |
931 | return 1; | |
932 | } | |
933 | EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); | |
934 | ||
935 | /************************************************************************ | |
936 | * Transmit handling | |
937 | ***********************************************************************/ | |
938 | ||
939 | /* Build an L2TP header for the session into the buffer provided. | |
940 | */ | |
f7faffa3 | 941 | static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) |
fd558d18 | 942 | { |
f7faffa3 | 943 | struct l2tp_tunnel *tunnel = session->tunnel; |
fd558d18 | 944 | __be16 *bufp = buf; |
f7faffa3 | 945 | __be16 *optr = buf; |
fd558d18 JC |
946 | u16 flags = L2TP_HDR_VER_2; |
947 | u32 tunnel_id = tunnel->peer_tunnel_id; | |
948 | u32 session_id = session->peer_session_id; | |
949 | ||
950 | if (session->send_seq) | |
951 | flags |= L2TP_HDRFLAG_S; | |
952 | ||
953 | /* Setup L2TP header. */ | |
954 | *bufp++ = htons(flags); | |
955 | *bufp++ = htons(tunnel_id); | |
956 | *bufp++ = htons(session_id); | |
957 | if (session->send_seq) { | |
958 | *bufp++ = htons(session->ns); | |
959 | *bufp++ = 0; | |
960 | session->ns++; | |
f7faffa3 | 961 | session->ns &= 0xffff; |
fd558d18 | 962 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
f7faffa3 | 963 | "%s: updated ns to %u\n", session->name, session->ns); |
fd558d18 | 964 | } |
f7faffa3 JC |
965 | |
966 | return bufp - optr; | |
fd558d18 JC |
967 | } |
968 | ||
f7faffa3 | 969 | static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) |
fd558d18 | 970 | { |
0d76751f | 971 | struct l2tp_tunnel *tunnel = session->tunnel; |
f7faffa3 JC |
972 | char *bufp = buf; |
973 | char *optr = bufp; | |
f7faffa3 | 974 | |
0d76751f JC |
975 | /* Setup L2TP header. The header differs slightly for UDP and |
976 | * IP encapsulations. For UDP, there is 4 bytes of flags. | |
977 | */ | |
978 | if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { | |
979 | u16 flags = L2TP_HDR_VER_3; | |
980 | *((__be16 *) bufp) = htons(flags); | |
981 | bufp += 2; | |
982 | *((__be16 *) bufp) = 0; | |
983 | bufp += 2; | |
984 | } | |
985 | ||
f7faffa3 JC |
986 | *((__be32 *) bufp) = htonl(session->peer_session_id); |
987 | bufp += 4; | |
988 | if (session->cookie_len) { | |
989 | memcpy(bufp, &session->cookie[0], session->cookie_len); | |
990 | bufp += session->cookie_len; | |
991 | } | |
992 | if (session->l2specific_len) { | |
993 | if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { | |
994 | u32 l2h = 0; | |
995 | if (session->send_seq) { | |
996 | l2h = 0x40000000 | session->ns; | |
997 | session->ns++; | |
998 | session->ns &= 0xffffff; | |
999 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
1000 | "%s: updated ns to %u\n", session->name, session->ns); | |
1001 | } | |
1002 | ||
1003 | *((__be32 *) bufp) = htonl(l2h); | |
1004 | } | |
1005 | bufp += session->l2specific_len; | |
1006 | } | |
1007 | if (session->offset) | |
1008 | bufp += session->offset; | |
fd558d18 | 1009 | |
f7faffa3 | 1010 | return bufp - optr; |
fd558d18 | 1011 | } |
fd558d18 | 1012 | |
fc130840 | 1013 | static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, |
d9d8da80 | 1014 | struct flowi *fl, size_t data_len) |
fd558d18 JC |
1015 | { |
1016 | struct l2tp_tunnel *tunnel = session->tunnel; | |
1017 | unsigned int len = skb->len; | |
1018 | int error; | |
5de7aee5 | 1019 | struct l2tp_stats *tstats, *sstats; |
fd558d18 JC |
1020 | |
1021 | /* Debug */ | |
1022 | if (session->send_seq) | |
1023 | PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, | |
f7faffa3 | 1024 | "%s: send %Zd bytes, ns=%u\n", session->name, |
fd558d18 JC |
1025 | data_len, session->ns - 1); |
1026 | else | |
1027 | PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, | |
1028 | "%s: send %Zd bytes\n", session->name, data_len); | |
1029 | ||
1030 | if (session->debug & L2TP_MSG_DATA) { | |
1031 | int i; | |
0d76751f JC |
1032 | int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; |
1033 | unsigned char *datap = skb->data + uhlen; | |
fd558d18 JC |
1034 | |
1035 | printk(KERN_DEBUG "%s: xmit:", session->name); | |
0d76751f | 1036 | for (i = 0; i < (len - uhlen); i++) { |
fd558d18 JC |
1037 | printk(" %02X", *datap++); |
1038 | if (i == 31) { | |
1039 | printk(" ..."); | |
1040 | break; | |
1041 | } | |
1042 | } | |
1043 | printk("\n"); | |
1044 | } | |
1045 | ||
1046 | /* Queue the packet to IP for output */ | |
4e15ed4d | 1047 | skb->local_df = 1; |
d2cf3361 BL |
1048 | #if IS_ENABLED(CONFIG_IPV6) |
1049 | if (skb->sk->sk_family == PF_INET6) | |
1050 | error = inet6_csk_xmit(skb, NULL); | |
1051 | else | |
1052 | #endif | |
1053 | error = ip_queue_xmit(skb, fl); | |
fd558d18 JC |
1054 | |
1055 | /* Update stats */ | |
5de7aee5 JC |
1056 | tstats = &tunnel->stats; |
1057 | u64_stats_update_begin(&tstats->syncp); | |
1058 | sstats = &session->stats; | |
1059 | u64_stats_update_begin(&sstats->syncp); | |
fd558d18 | 1060 | if (error >= 0) { |
5de7aee5 JC |
1061 | tstats->tx_packets++; |
1062 | tstats->tx_bytes += len; | |
1063 | sstats->tx_packets++; | |
1064 | sstats->tx_bytes += len; | |
fd558d18 | 1065 | } else { |
5de7aee5 JC |
1066 | tstats->tx_errors++; |
1067 | sstats->tx_errors++; | |
fd558d18 | 1068 | } |
5de7aee5 JC |
1069 | u64_stats_update_end(&tstats->syncp); |
1070 | u64_stats_update_end(&sstats->syncp); | |
fd558d18 JC |
1071 | |
1072 | return 0; | |
1073 | } | |
fd558d18 JC |
1074 | |
1075 | /* Automatically called when the skb is freed. | |
1076 | */ | |
1077 | static void l2tp_sock_wfree(struct sk_buff *skb) | |
1078 | { | |
1079 | sock_put(skb->sk); | |
1080 | } | |
1081 | ||
1082 | /* For data skbs that we transmit, we associate with the tunnel socket | |
1083 | * but don't do accounting. | |
1084 | */ | |
1085 | static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk) | |
1086 | { | |
1087 | sock_hold(sk); | |
1088 | skb->sk = sk; | |
1089 | skb->destructor = l2tp_sock_wfree; | |
1090 | } | |
1091 | ||
d2cf3361 BL |
1092 | #if IS_ENABLED(CONFIG_IPV6) |
1093 | static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb, | |
1094 | int udp_len) | |
1095 | { | |
1096 | struct ipv6_pinfo *np = inet6_sk(sk); | |
1097 | struct udphdr *uh = udp_hdr(skb); | |
1098 | ||
1099 | if (!skb_dst(skb) || !skb_dst(skb)->dev || | |
1100 | !(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) { | |
1101 | __wsum csum = skb_checksum(skb, 0, udp_len, 0); | |
1102 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
1103 | uh->check = csum_ipv6_magic(&np->saddr, &np->daddr, udp_len, | |
1104 | IPPROTO_UDP, csum); | |
1105 | if (uh->check == 0) | |
1106 | uh->check = CSUM_MANGLED_0; | |
1107 | } else { | |
1108 | skb->ip_summed = CHECKSUM_PARTIAL; | |
1109 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
1110 | skb->csum_offset = offsetof(struct udphdr, check); | |
1111 | uh->check = ~csum_ipv6_magic(&np->saddr, &np->daddr, | |
1112 | udp_len, IPPROTO_UDP, 0); | |
1113 | } | |
1114 | } | |
1115 | #endif | |
1116 | ||
fd558d18 JC |
1117 | /* If caller requires the skb to have a ppp header, the header must be |
1118 | * inserted in the skb data before calling this function. | |
1119 | */ | |
1120 | int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) | |
1121 | { | |
1122 | int data_len = skb->len; | |
0d76751f JC |
1123 | struct l2tp_tunnel *tunnel = session->tunnel; |
1124 | struct sock *sk = tunnel->sock; | |
d9d8da80 | 1125 | struct flowi *fl; |
fd558d18 | 1126 | struct udphdr *uh; |
fd558d18 JC |
1127 | struct inet_sock *inet; |
1128 | __wsum csum; | |
1129 | int old_headroom; | |
1130 | int new_headroom; | |
1131 | int headroom; | |
0d76751f JC |
1132 | int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; |
1133 | int udp_len; | |
fd558d18 JC |
1134 | |
1135 | /* Check that there's enough headroom in the skb to insert IP, | |
1136 | * UDP and L2TP headers. If not enough, expand it to | |
1137 | * make room. Adjust truesize. | |
1138 | */ | |
1139 | headroom = NET_SKB_PAD + sizeof(struct iphdr) + | |
0d76751f | 1140 | uhlen + hdr_len; |
fd558d18 | 1141 | old_headroom = skb_headroom(skb); |
835acf5d ED |
1142 | if (skb_cow_head(skb, headroom)) { |
1143 | dev_kfree_skb(skb); | |
fd558d18 | 1144 | goto abort; |
835acf5d | 1145 | } |
fd558d18 JC |
1146 | |
1147 | new_headroom = skb_headroom(skb); | |
1148 | skb_orphan(skb); | |
1149 | skb->truesize += new_headroom - old_headroom; | |
1150 | ||
1151 | /* Setup L2TP header */ | |
f7faffa3 | 1152 | session->build_header(session, __skb_push(skb, hdr_len)); |
fd558d18 | 1153 | |
0d76751f | 1154 | /* Reset skb netfilter state */ |
fd558d18 JC |
1155 | memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); |
1156 | IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | | |
1157 | IPSKB_REROUTED); | |
1158 | nf_reset(skb); | |
1159 | ||
6af88da1 DM |
1160 | bh_lock_sock(sk); |
1161 | if (sock_owned_by_user(sk)) { | |
1162 | dev_kfree_skb(skb); | |
1163 | goto out_unlock; | |
1164 | } | |
1165 | ||
fd558d18 JC |
1166 | /* Get routing info from the tunnel socket */ |
1167 | skb_dst_drop(skb); | |
71b1391a | 1168 | skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0))); |
fd558d18 | 1169 | |
d9d8da80 DM |
1170 | inet = inet_sk(sk); |
1171 | fl = &inet->cork.fl; | |
0d76751f JC |
1172 | switch (tunnel->encap) { |
1173 | case L2TP_ENCAPTYPE_UDP: | |
1174 | /* Setup UDP header */ | |
0d76751f JC |
1175 | __skb_push(skb, sizeof(*uh)); |
1176 | skb_reset_transport_header(skb); | |
1177 | uh = udp_hdr(skb); | |
1178 | uh->source = inet->inet_sport; | |
1179 | uh->dest = inet->inet_dport; | |
1180 | udp_len = uhlen + hdr_len + data_len; | |
1181 | uh->len = htons(udp_len); | |
1182 | uh->check = 0; | |
1183 | ||
1184 | /* Calculate UDP checksum if configured to do so */ | |
d2cf3361 BL |
1185 | #if IS_ENABLED(CONFIG_IPV6) |
1186 | if (sk->sk_family == PF_INET6) | |
1187 | l2tp_xmit_ipv6_csum(sk, skb, udp_len); | |
1188 | else | |
1189 | #endif | |
0d76751f JC |
1190 | if (sk->sk_no_check == UDP_CSUM_NOXMIT) |
1191 | skb->ip_summed = CHECKSUM_NONE; | |
1192 | else if ((skb_dst(skb) && skb_dst(skb)->dev) && | |
1193 | (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) { | |
1194 | skb->ip_summed = CHECKSUM_COMPLETE; | |
1195 | csum = skb_checksum(skb, 0, udp_len, 0); | |
1196 | uh->check = csum_tcpudp_magic(inet->inet_saddr, | |
1197 | inet->inet_daddr, | |
1198 | udp_len, IPPROTO_UDP, csum); | |
1199 | if (uh->check == 0) | |
1200 | uh->check = CSUM_MANGLED_0; | |
1201 | } else { | |
1202 | skb->ip_summed = CHECKSUM_PARTIAL; | |
1203 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
1204 | skb->csum_offset = offsetof(struct udphdr, check); | |
1205 | uh->check = ~csum_tcpudp_magic(inet->inet_saddr, | |
1206 | inet->inet_daddr, | |
1207 | udp_len, IPPROTO_UDP, 0); | |
1208 | } | |
1209 | break; | |
1210 | ||
1211 | case L2TP_ENCAPTYPE_IP: | |
1212 | break; | |
fd558d18 JC |
1213 | } |
1214 | ||
0d76751f JC |
1215 | l2tp_skb_set_owner_w(skb, sk); |
1216 | ||
d9d8da80 | 1217 | l2tp_xmit_core(session, skb, fl, data_len); |
6af88da1 DM |
1218 | out_unlock: |
1219 | bh_unlock_sock(sk); | |
fd558d18 JC |
1220 | |
1221 | abort: | |
1222 | return 0; | |
1223 | } | |
1224 | EXPORT_SYMBOL_GPL(l2tp_xmit_skb); | |
1225 | ||
1226 | /***************************************************************************** | |
1227 | * Tinnel and session create/destroy. | |
1228 | *****************************************************************************/ | |
1229 | ||
1230 | /* Tunnel socket destruct hook. | |
1231 | * The tunnel context is deleted only when all session sockets have been | |
1232 | * closed. | |
1233 | */ | |
fc130840 | 1234 | static void l2tp_tunnel_destruct(struct sock *sk) |
fd558d18 JC |
1235 | { |
1236 | struct l2tp_tunnel *tunnel; | |
1237 | ||
1238 | tunnel = sk->sk_user_data; | |
1239 | if (tunnel == NULL) | |
1240 | goto end; | |
1241 | ||
1242 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, | |
1243 | "%s: closing...\n", tunnel->name); | |
1244 | ||
1245 | /* Close all sessions */ | |
1246 | l2tp_tunnel_closeall(tunnel); | |
1247 | ||
0d76751f JC |
1248 | switch (tunnel->encap) { |
1249 | case L2TP_ENCAPTYPE_UDP: | |
1250 | /* No longer an encapsulation socket. See net/ipv4/udp.c */ | |
1251 | (udp_sk(sk))->encap_type = 0; | |
1252 | (udp_sk(sk))->encap_rcv = NULL; | |
1253 | break; | |
1254 | case L2TP_ENCAPTYPE_IP: | |
1255 | break; | |
1256 | } | |
fd558d18 JC |
1257 | |
1258 | /* Remove hooks into tunnel socket */ | |
1259 | tunnel->sock = NULL; | |
1260 | sk->sk_destruct = tunnel->old_sk_destruct; | |
1261 | sk->sk_user_data = NULL; | |
1262 | ||
1263 | /* Call the original destructor */ | |
1264 | if (sk->sk_destruct) | |
1265 | (*sk->sk_destruct)(sk); | |
1266 | ||
1267 | /* We're finished with the socket */ | |
1268 | l2tp_tunnel_dec_refcount(tunnel); | |
1269 | ||
1270 | end: | |
1271 | return; | |
1272 | } | |
fd558d18 JC |
1273 | |
1274 | /* When the tunnel is closed, all the attached sessions need to go too. | |
1275 | */ | |
fc130840 | 1276 | static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) |
fd558d18 JC |
1277 | { |
1278 | int hash; | |
1279 | struct hlist_node *walk; | |
1280 | struct hlist_node *tmp; | |
1281 | struct l2tp_session *session; | |
1282 | ||
1283 | BUG_ON(tunnel == NULL); | |
1284 | ||
1285 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, | |
1286 | "%s: closing all sessions...\n", tunnel->name); | |
1287 | ||
1288 | write_lock_bh(&tunnel->hlist_lock); | |
1289 | for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { | |
1290 | again: | |
1291 | hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { | |
1292 | session = hlist_entry(walk, struct l2tp_session, hlist); | |
1293 | ||
1294 | PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO, | |
1295 | "%s: closing session\n", session->name); | |
1296 | ||
1297 | hlist_del_init(&session->hlist); | |
1298 | ||
1299 | /* Since we should hold the sock lock while | |
1300 | * doing any unbinding, we need to release the | |
1301 | * lock we're holding before taking that lock. | |
1302 | * Hold a reference to the sock so it doesn't | |
1303 | * disappear as we're jumping between locks. | |
1304 | */ | |
1305 | if (session->ref != NULL) | |
1306 | (*session->ref)(session); | |
1307 | ||
1308 | write_unlock_bh(&tunnel->hlist_lock); | |
1309 | ||
f7faffa3 JC |
1310 | if (tunnel->version != L2TP_HDR_VER_2) { |
1311 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
1312 | ||
e02d494d JC |
1313 | spin_lock_bh(&pn->l2tp_session_hlist_lock); |
1314 | hlist_del_init_rcu(&session->global_hlist); | |
1315 | spin_unlock_bh(&pn->l2tp_session_hlist_lock); | |
1316 | synchronize_rcu(); | |
f7faffa3 JC |
1317 | } |
1318 | ||
fd558d18 JC |
1319 | if (session->session_close != NULL) |
1320 | (*session->session_close)(session); | |
1321 | ||
1322 | if (session->deref != NULL) | |
1323 | (*session->deref)(session); | |
1324 | ||
1325 | write_lock_bh(&tunnel->hlist_lock); | |
1326 | ||
1327 | /* Now restart from the beginning of this hash | |
1328 | * chain. We always remove a session from the | |
1329 | * list so we are guaranteed to make forward | |
1330 | * progress. | |
1331 | */ | |
1332 | goto again; | |
1333 | } | |
1334 | } | |
1335 | write_unlock_bh(&tunnel->hlist_lock); | |
1336 | } | |
fd558d18 JC |
1337 | |
1338 | /* Really kill the tunnel. | |
1339 | * Come here only when all sessions have been cleared from the tunnel. | |
1340 | */ | |
fc130840 | 1341 | static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) |
fd558d18 JC |
1342 | { |
1343 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
1344 | ||
1345 | BUG_ON(atomic_read(&tunnel->ref_count) != 0); | |
1346 | BUG_ON(tunnel->sock != NULL); | |
1347 | ||
1348 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, | |
1349 | "%s: free...\n", tunnel->name); | |
1350 | ||
1351 | /* Remove from tunnel list */ | |
e02d494d JC |
1352 | spin_lock_bh(&pn->l2tp_tunnel_list_lock); |
1353 | list_del_rcu(&tunnel->list); | |
1354 | spin_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
1355 | synchronize_rcu(); | |
fd558d18 JC |
1356 | |
1357 | atomic_dec(&l2tp_tunnel_count); | |
1358 | kfree(tunnel); | |
1359 | } | |
fd558d18 | 1360 | |
789a4a2c JC |
1361 | /* Create a socket for the tunnel, if one isn't set up by |
1362 | * userspace. This is used for static tunnels where there is no | |
1363 | * managing L2TP daemon. | |
1364 | */ | |
1365 | static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp) | |
1366 | { | |
1367 | int err = -EINVAL; | |
1368 | struct sockaddr_in udp_addr; | |
1369 | struct sockaddr_l2tpip ip_addr; | |
7bddd0db | 1370 | struct socket *sock = NULL; |
789a4a2c JC |
1371 | |
1372 | switch (cfg->encap) { | |
1373 | case L2TP_ENCAPTYPE_UDP: | |
1374 | err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp); | |
1375 | if (err < 0) | |
1376 | goto out; | |
1377 | ||
1378 | sock = *sockp; | |
1379 | ||
1380 | memset(&udp_addr, 0, sizeof(udp_addr)); | |
1381 | udp_addr.sin_family = AF_INET; | |
1382 | udp_addr.sin_addr = cfg->local_ip; | |
1383 | udp_addr.sin_port = htons(cfg->local_udp_port); | |
1384 | err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr)); | |
1385 | if (err < 0) | |
1386 | goto out; | |
1387 | ||
1388 | udp_addr.sin_family = AF_INET; | |
1389 | udp_addr.sin_addr = cfg->peer_ip; | |
1390 | udp_addr.sin_port = htons(cfg->peer_udp_port); | |
1391 | err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0); | |
1392 | if (err < 0) | |
1393 | goto out; | |
1394 | ||
1395 | if (!cfg->use_udp_checksums) | |
1396 | sock->sk->sk_no_check = UDP_CSUM_NOXMIT; | |
1397 | ||
1398 | break; | |
1399 | ||
1400 | case L2TP_ENCAPTYPE_IP: | |
1401 | err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp); | |
1402 | if (err < 0) | |
1403 | goto out; | |
1404 | ||
1405 | sock = *sockp; | |
1406 | ||
1407 | memset(&ip_addr, 0, sizeof(ip_addr)); | |
1408 | ip_addr.l2tp_family = AF_INET; | |
1409 | ip_addr.l2tp_addr = cfg->local_ip; | |
1410 | ip_addr.l2tp_conn_id = tunnel_id; | |
1411 | err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr)); | |
1412 | if (err < 0) | |
1413 | goto out; | |
1414 | ||
1415 | ip_addr.l2tp_family = AF_INET; | |
1416 | ip_addr.l2tp_addr = cfg->peer_ip; | |
1417 | ip_addr.l2tp_conn_id = peer_tunnel_id; | |
1418 | err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0); | |
1419 | if (err < 0) | |
1420 | goto out; | |
1421 | ||
1422 | break; | |
1423 | ||
1424 | default: | |
1425 | goto out; | |
1426 | } | |
1427 | ||
1428 | out: | |
1429 | if ((err < 0) && sock) { | |
1430 | sock_release(sock); | |
1431 | *sockp = NULL; | |
1432 | } | |
1433 | ||
1434 | return err; | |
1435 | } | |
1436 | ||
fd558d18 JC |
1437 | 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) |
1438 | { | |
1439 | struct l2tp_tunnel *tunnel = NULL; | |
1440 | int err; | |
1441 | struct socket *sock = NULL; | |
1442 | struct sock *sk = NULL; | |
1443 | struct l2tp_net *pn; | |
0d76751f | 1444 | enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; |
fd558d18 JC |
1445 | |
1446 | /* Get the tunnel socket from the fd, which was opened by | |
789a4a2c JC |
1447 | * the userspace L2TP daemon. If not specified, create a |
1448 | * kernel socket. | |
fd558d18 | 1449 | */ |
789a4a2c JC |
1450 | if (fd < 0) { |
1451 | err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock); | |
1452 | if (err < 0) | |
1453 | goto err; | |
1454 | } else { | |
1455 | err = -EBADF; | |
1456 | sock = sockfd_lookup(fd, &err); | |
1457 | if (!sock) { | |
1458 | printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n", | |
1459 | tunnel_id, fd, err); | |
1460 | goto err; | |
1461 | } | |
fd558d18 JC |
1462 | } |
1463 | ||
1464 | sk = sock->sk; | |
1465 | ||
0d76751f JC |
1466 | if (cfg != NULL) |
1467 | encap = cfg->encap; | |
1468 | ||
fd558d18 | 1469 | /* Quick sanity checks */ |
0d76751f JC |
1470 | switch (encap) { |
1471 | case L2TP_ENCAPTYPE_UDP: | |
1472 | err = -EPROTONOSUPPORT; | |
1473 | if (sk->sk_protocol != IPPROTO_UDP) { | |
1474 | printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", | |
1475 | tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); | |
1476 | goto err; | |
1477 | } | |
1478 | break; | |
1479 | case L2TP_ENCAPTYPE_IP: | |
1480 | err = -EPROTONOSUPPORT; | |
1481 | if (sk->sk_protocol != IPPROTO_L2TP) { | |
1482 | printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", | |
1483 | tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP); | |
1484 | goto err; | |
1485 | } | |
1486 | break; | |
fd558d18 JC |
1487 | } |
1488 | ||
1489 | /* Check if this socket has already been prepped */ | |
1490 | tunnel = (struct l2tp_tunnel *)sk->sk_user_data; | |
1491 | if (tunnel != NULL) { | |
1492 | /* This socket has already been prepped */ | |
1493 | err = -EBUSY; | |
1494 | goto err; | |
1495 | } | |
1496 | ||
fd558d18 JC |
1497 | tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); |
1498 | if (tunnel == NULL) { | |
1499 | err = -ENOMEM; | |
1500 | goto err; | |
1501 | } | |
1502 | ||
1503 | tunnel->version = version; | |
1504 | tunnel->tunnel_id = tunnel_id; | |
1505 | tunnel->peer_tunnel_id = peer_tunnel_id; | |
1506 | tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; | |
1507 | ||
1508 | tunnel->magic = L2TP_TUNNEL_MAGIC; | |
1509 | sprintf(&tunnel->name[0], "tunl %u", tunnel_id); | |
1510 | rwlock_init(&tunnel->hlist_lock); | |
1511 | ||
1512 | /* The net we belong to */ | |
1513 | tunnel->l2tp_net = net; | |
1514 | pn = l2tp_pernet(net); | |
1515 | ||
0d76751f | 1516 | if (cfg != NULL) |
fd558d18 JC |
1517 | tunnel->debug = cfg->debug; |
1518 | ||
1519 | /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ | |
0d76751f JC |
1520 | tunnel->encap = encap; |
1521 | if (encap == L2TP_ENCAPTYPE_UDP) { | |
1522 | /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ | |
1523 | udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; | |
1524 | udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv; | |
d2cf3361 BL |
1525 | #if IS_ENABLED(CONFIG_IPV6) |
1526 | if (sk->sk_family == PF_INET6) | |
1527 | udpv6_encap_enable(); | |
1528 | else | |
1529 | #endif | |
447167bf | 1530 | udp_encap_enable(); |
0d76751f | 1531 | } |
fd558d18 JC |
1532 | |
1533 | sk->sk_user_data = tunnel; | |
1534 | ||
1535 | /* Hook on the tunnel socket destructor so that we can cleanup | |
1536 | * if the tunnel socket goes away. | |
1537 | */ | |
1538 | tunnel->old_sk_destruct = sk->sk_destruct; | |
1539 | sk->sk_destruct = &l2tp_tunnel_destruct; | |
1540 | tunnel->sock = sk; | |
1541 | sk->sk_allocation = GFP_ATOMIC; | |
1542 | ||
1543 | /* Add tunnel to our list */ | |
1544 | INIT_LIST_HEAD(&tunnel->list); | |
fd558d18 JC |
1545 | atomic_inc(&l2tp_tunnel_count); |
1546 | ||
1547 | /* Bump the reference count. The tunnel context is deleted | |
1769192a | 1548 | * only when this drops to zero. Must be done before list insertion |
fd558d18 JC |
1549 | */ |
1550 | l2tp_tunnel_inc_refcount(tunnel); | |
1769192a ED |
1551 | spin_lock_bh(&pn->l2tp_tunnel_list_lock); |
1552 | list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); | |
1553 | spin_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
fd558d18 JC |
1554 | |
1555 | err = 0; | |
1556 | err: | |
1557 | if (tunnelp) | |
1558 | *tunnelp = tunnel; | |
1559 | ||
789a4a2c JC |
1560 | /* If tunnel's socket was created by the kernel, it doesn't |
1561 | * have a file. | |
1562 | */ | |
1563 | if (sock && sock->file) | |
fd558d18 JC |
1564 | sockfd_put(sock); |
1565 | ||
1566 | return err; | |
1567 | } | |
1568 | EXPORT_SYMBOL_GPL(l2tp_tunnel_create); | |
1569 | ||
309795f4 JC |
1570 | /* This function is used by the netlink TUNNEL_DELETE command. |
1571 | */ | |
1572 | int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) | |
1573 | { | |
1574 | int err = 0; | |
789a4a2c | 1575 | struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL; |
309795f4 JC |
1576 | |
1577 | /* Force the tunnel socket to close. This will eventually | |
1578 | * cause the tunnel to be deleted via the normal socket close | |
1579 | * mechanisms when userspace closes the tunnel socket. | |
1580 | */ | |
789a4a2c JC |
1581 | if (sock != NULL) { |
1582 | err = inet_shutdown(sock, 2); | |
1583 | ||
1584 | /* If the tunnel's socket was created by the kernel, | |
1585 | * close the socket here since the socket was not | |
1586 | * created by userspace. | |
1587 | */ | |
1588 | if (sock->file == NULL) | |
1589 | err = inet_release(sock); | |
1590 | } | |
309795f4 JC |
1591 | |
1592 | return err; | |
1593 | } | |
1594 | EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); | |
1595 | ||
fd558d18 JC |
1596 | /* Really kill the session. |
1597 | */ | |
1598 | void l2tp_session_free(struct l2tp_session *session) | |
1599 | { | |
1600 | struct l2tp_tunnel *tunnel; | |
1601 | ||
1602 | BUG_ON(atomic_read(&session->ref_count) != 0); | |
1603 | ||
1604 | tunnel = session->tunnel; | |
1605 | if (tunnel != NULL) { | |
1606 | BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); | |
1607 | ||
1608 | /* Delete the session from the hash */ | |
1609 | write_lock_bh(&tunnel->hlist_lock); | |
1610 | hlist_del_init(&session->hlist); | |
1611 | write_unlock_bh(&tunnel->hlist_lock); | |
1612 | ||
f7faffa3 JC |
1613 | /* Unlink from the global hash if not L2TPv2 */ |
1614 | if (tunnel->version != L2TP_HDR_VER_2) { | |
1615 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
1616 | ||
e02d494d JC |
1617 | spin_lock_bh(&pn->l2tp_session_hlist_lock); |
1618 | hlist_del_init_rcu(&session->global_hlist); | |
1619 | spin_unlock_bh(&pn->l2tp_session_hlist_lock); | |
1620 | synchronize_rcu(); | |
f7faffa3 JC |
1621 | } |
1622 | ||
fd558d18 JC |
1623 | if (session->session_id != 0) |
1624 | atomic_dec(&l2tp_session_count); | |
1625 | ||
1626 | sock_put(tunnel->sock); | |
1627 | ||
1628 | /* This will delete the tunnel context if this | |
1629 | * is the last session on the tunnel. | |
1630 | */ | |
1631 | session->tunnel = NULL; | |
1632 | l2tp_tunnel_dec_refcount(tunnel); | |
1633 | } | |
1634 | ||
1635 | kfree(session); | |
1636 | ||
1637 | return; | |
1638 | } | |
1639 | EXPORT_SYMBOL_GPL(l2tp_session_free); | |
1640 | ||
309795f4 JC |
1641 | /* This function is used by the netlink SESSION_DELETE command and by |
1642 | pseudowire modules. | |
1643 | */ | |
1644 | int l2tp_session_delete(struct l2tp_session *session) | |
1645 | { | |
1646 | if (session->session_close != NULL) | |
1647 | (*session->session_close)(session); | |
1648 | ||
1649 | l2tp_session_dec_refcount(session); | |
1650 | ||
1651 | return 0; | |
1652 | } | |
1653 | EXPORT_SYMBOL_GPL(l2tp_session_delete); | |
1654 | ||
1655 | ||
f7faffa3 JC |
1656 | /* We come here whenever a session's send_seq, cookie_len or |
1657 | * l2specific_len parameters are set. | |
1658 | */ | |
fc130840 | 1659 | static void l2tp_session_set_header_len(struct l2tp_session *session, int version) |
f7faffa3 JC |
1660 | { |
1661 | if (version == L2TP_HDR_VER_2) { | |
1662 | session->hdr_len = 6; | |
1663 | if (session->send_seq) | |
1664 | session->hdr_len += 4; | |
1665 | } else { | |
0d76751f JC |
1666 | session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset; |
1667 | if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP) | |
1668 | session->hdr_len += 4; | |
f7faffa3 JC |
1669 | } |
1670 | ||
1671 | } | |
f7faffa3 | 1672 | |
fd558d18 JC |
1673 | 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) |
1674 | { | |
1675 | struct l2tp_session *session; | |
1676 | ||
1677 | session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); | |
1678 | if (session != NULL) { | |
1679 | session->magic = L2TP_SESSION_MAGIC; | |
1680 | session->tunnel = tunnel; | |
1681 | ||
1682 | session->session_id = session_id; | |
1683 | session->peer_session_id = peer_session_id; | |
f7faffa3 | 1684 | session->nr = 1; |
fd558d18 JC |
1685 | |
1686 | sprintf(&session->name[0], "sess %u/%u", | |
1687 | tunnel->tunnel_id, session->session_id); | |
1688 | ||
1689 | skb_queue_head_init(&session->reorder_q); | |
1690 | ||
1691 | INIT_HLIST_NODE(&session->hlist); | |
f7faffa3 | 1692 | INIT_HLIST_NODE(&session->global_hlist); |
fd558d18 JC |
1693 | |
1694 | /* Inherit debug options from tunnel */ | |
1695 | session->debug = tunnel->debug; | |
1696 | ||
1697 | if (cfg) { | |
f7faffa3 | 1698 | session->pwtype = cfg->pw_type; |
fd558d18 | 1699 | session->debug = cfg->debug; |
fd558d18 JC |
1700 | session->mtu = cfg->mtu; |
1701 | session->mru = cfg->mru; | |
1702 | session->send_seq = cfg->send_seq; | |
1703 | session->recv_seq = cfg->recv_seq; | |
1704 | session->lns_mode = cfg->lns_mode; | |
f7faffa3 JC |
1705 | session->reorder_timeout = cfg->reorder_timeout; |
1706 | session->offset = cfg->offset; | |
1707 | session->l2specific_type = cfg->l2specific_type; | |
1708 | session->l2specific_len = cfg->l2specific_len; | |
1709 | session->cookie_len = cfg->cookie_len; | |
1710 | memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); | |
1711 | session->peer_cookie_len = cfg->peer_cookie_len; | |
1712 | memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); | |
fd558d18 JC |
1713 | } |
1714 | ||
f7faffa3 JC |
1715 | if (tunnel->version == L2TP_HDR_VER_2) |
1716 | session->build_header = l2tp_build_l2tpv2_header; | |
1717 | else | |
1718 | session->build_header = l2tp_build_l2tpv3_header; | |
1719 | ||
1720 | l2tp_session_set_header_len(session, tunnel->version); | |
1721 | ||
fd558d18 JC |
1722 | /* Bump the reference count. The session context is deleted |
1723 | * only when this drops to zero. | |
1724 | */ | |
1725 | l2tp_session_inc_refcount(session); | |
1726 | l2tp_tunnel_inc_refcount(tunnel); | |
1727 | ||
1728 | /* Ensure tunnel socket isn't deleted */ | |
1729 | sock_hold(tunnel->sock); | |
1730 | ||
1731 | /* Add session to the tunnel's hash list */ | |
1732 | write_lock_bh(&tunnel->hlist_lock); | |
1733 | hlist_add_head(&session->hlist, | |
1734 | l2tp_session_id_hash(tunnel, session_id)); | |
1735 | write_unlock_bh(&tunnel->hlist_lock); | |
1736 | ||
f7faffa3 JC |
1737 | /* And to the global session list if L2TPv3 */ |
1738 | if (tunnel->version != L2TP_HDR_VER_2) { | |
1739 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
1740 | ||
e02d494d JC |
1741 | spin_lock_bh(&pn->l2tp_session_hlist_lock); |
1742 | hlist_add_head_rcu(&session->global_hlist, | |
1743 | l2tp_session_id_hash_2(pn, session_id)); | |
1744 | spin_unlock_bh(&pn->l2tp_session_hlist_lock); | |
f7faffa3 JC |
1745 | } |
1746 | ||
fd558d18 JC |
1747 | /* Ignore management session in session count value */ |
1748 | if (session->session_id != 0) | |
1749 | atomic_inc(&l2tp_session_count); | |
1750 | } | |
1751 | ||
1752 | return session; | |
1753 | } | |
1754 | EXPORT_SYMBOL_GPL(l2tp_session_create); | |
1755 | ||
1756 | /***************************************************************************** | |
1757 | * Init and cleanup | |
1758 | *****************************************************************************/ | |
1759 | ||
1760 | static __net_init int l2tp_init_net(struct net *net) | |
1761 | { | |
e773aaff | 1762 | struct l2tp_net *pn = net_generic(net, l2tp_net_id); |
f7faffa3 | 1763 | int hash; |
fd558d18 | 1764 | |
fd558d18 | 1765 | INIT_LIST_HEAD(&pn->l2tp_tunnel_list); |
e02d494d | 1766 | spin_lock_init(&pn->l2tp_tunnel_list_lock); |
fd558d18 | 1767 | |
f7faffa3 JC |
1768 | for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) |
1769 | INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]); | |
1770 | ||
e02d494d | 1771 | spin_lock_init(&pn->l2tp_session_hlist_lock); |
f7faffa3 | 1772 | |
fd558d18 | 1773 | return 0; |
fd558d18 JC |
1774 | } |
1775 | ||
1776 | static struct pernet_operations l2tp_net_ops = { | |
1777 | .init = l2tp_init_net, | |
fd558d18 JC |
1778 | .id = &l2tp_net_id, |
1779 | .size = sizeof(struct l2tp_net), | |
1780 | }; | |
1781 | ||
1782 | static int __init l2tp_init(void) | |
1783 | { | |
1784 | int rc = 0; | |
1785 | ||
1786 | rc = register_pernet_device(&l2tp_net_ops); | |
1787 | if (rc) | |
1788 | goto out; | |
1789 | ||
1790 | printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION); | |
1791 | ||
1792 | out: | |
1793 | return rc; | |
1794 | } | |
1795 | ||
1796 | static void __exit l2tp_exit(void) | |
1797 | { | |
1798 | unregister_pernet_device(&l2tp_net_ops); | |
1799 | } | |
1800 | ||
1801 | module_init(l2tp_init); | |
1802 | module_exit(l2tp_exit); | |
1803 | ||
1804 | MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); | |
1805 | MODULE_DESCRIPTION("L2TP core"); | |
1806 | MODULE_LICENSE("GPL"); | |
1807 | MODULE_VERSION(L2TP_DRV_VERSION); | |
1808 |