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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> | |
24 | #include <linux/uaccess.h> | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/spinlock.h> | |
28 | #include <linux/kthread.h> | |
29 | #include <linux/sched.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/errno.h> | |
32 | #include <linux/jiffies.h> | |
33 | ||
34 | #include <linux/netdevice.h> | |
35 | #include <linux/net.h> | |
36 | #include <linux/inetdevice.h> | |
37 | #include <linux/skbuff.h> | |
38 | #include <linux/init.h> | |
39 | #include <linux/ip.h> | |
40 | #include <linux/udp.h> | |
41 | #include <linux/hash.h> | |
42 | #include <linux/sort.h> | |
43 | #include <linux/file.h> | |
44 | #include <linux/nsproxy.h> | |
45 | #include <net/net_namespace.h> | |
46 | #include <net/netns/generic.h> | |
47 | #include <net/dst.h> | |
48 | #include <net/ip.h> | |
49 | #include <net/udp.h> | |
50 | #include <net/xfrm.h> | |
51 | ||
52 | #include <asm/byteorder.h> | |
53 | #include <asm/atomic.h> | |
54 | ||
55 | #include "l2tp_core.h" | |
56 | ||
57 | #define L2TP_DRV_VERSION "V2.0" | |
58 | ||
59 | /* L2TP header constants */ | |
60 | #define L2TP_HDRFLAG_T 0x8000 | |
61 | #define L2TP_HDRFLAG_L 0x4000 | |
62 | #define L2TP_HDRFLAG_S 0x0800 | |
63 | #define L2TP_HDRFLAG_O 0x0200 | |
64 | #define L2TP_HDRFLAG_P 0x0100 | |
65 | ||
66 | #define L2TP_HDR_VER_MASK 0x000F | |
67 | #define L2TP_HDR_VER_2 0x0002 | |
68 | ||
69 | /* L2TPv3 default L2-specific sublayer */ | |
70 | #define L2TP_SLFLAG_S 0x40000000 | |
71 | #define L2TP_SL_SEQ_MASK 0x00ffffff | |
72 | ||
73 | #define L2TP_HDR_SIZE_SEQ 10 | |
74 | #define L2TP_HDR_SIZE_NOSEQ 6 | |
75 | ||
76 | /* Default trace flags */ | |
77 | #define L2TP_DEFAULT_DEBUG_FLAGS 0 | |
78 | ||
79 | #define PRINTK(_mask, _type, _lvl, _fmt, args...) \ | |
80 | do { \ | |
81 | if ((_mask) & (_type)) \ | |
82 | printk(_lvl "L2TP: " _fmt, ##args); \ | |
83 | } while (0) | |
84 | ||
85 | /* Private data stored for received packets in the skb. | |
86 | */ | |
87 | struct l2tp_skb_cb { | |
88 | u16 ns; | |
89 | u16 has_seq; | |
90 | u16 length; | |
91 | unsigned long expires; | |
92 | }; | |
93 | ||
94 | #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) | |
95 | ||
96 | static atomic_t l2tp_tunnel_count; | |
97 | static atomic_t l2tp_session_count; | |
98 | ||
99 | /* per-net private data for this module */ | |
100 | static unsigned int l2tp_net_id; | |
101 | struct l2tp_net { | |
102 | struct list_head l2tp_tunnel_list; | |
103 | rwlock_t l2tp_tunnel_list_lock; | |
104 | }; | |
105 | ||
106 | static inline struct l2tp_net *l2tp_pernet(struct net *net) | |
107 | { | |
108 | BUG_ON(!net); | |
109 | ||
110 | return net_generic(net, l2tp_net_id); | |
111 | } | |
112 | ||
113 | /* Session hash list. | |
114 | * The session_id SHOULD be random according to RFC2661, but several | |
115 | * L2TP implementations (Cisco and Microsoft) use incrementing | |
116 | * session_ids. So we do a real hash on the session_id, rather than a | |
117 | * simple bitmask. | |
118 | */ | |
119 | static inline struct hlist_head * | |
120 | l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) | |
121 | { | |
122 | return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; | |
123 | } | |
124 | ||
125 | /* Lookup a session by id | |
126 | */ | |
127 | struct l2tp_session *l2tp_session_find(struct l2tp_tunnel *tunnel, u32 session_id) | |
128 | { | |
129 | struct hlist_head *session_list = | |
130 | l2tp_session_id_hash(tunnel, session_id); | |
131 | struct l2tp_session *session; | |
132 | struct hlist_node *walk; | |
133 | ||
134 | read_lock_bh(&tunnel->hlist_lock); | |
135 | hlist_for_each_entry(session, walk, session_list, hlist) { | |
136 | if (session->session_id == session_id) { | |
137 | read_unlock_bh(&tunnel->hlist_lock); | |
138 | return session; | |
139 | } | |
140 | } | |
141 | read_unlock_bh(&tunnel->hlist_lock); | |
142 | ||
143 | return NULL; | |
144 | } | |
145 | EXPORT_SYMBOL_GPL(l2tp_session_find); | |
146 | ||
147 | struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth) | |
148 | { | |
149 | int hash; | |
150 | struct hlist_node *walk; | |
151 | struct l2tp_session *session; | |
152 | int count = 0; | |
153 | ||
154 | read_lock_bh(&tunnel->hlist_lock); | |
155 | for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { | |
156 | hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) { | |
157 | if (++count > nth) { | |
158 | read_unlock_bh(&tunnel->hlist_lock); | |
159 | return session; | |
160 | } | |
161 | } | |
162 | } | |
163 | ||
164 | read_unlock_bh(&tunnel->hlist_lock); | |
165 | ||
166 | return NULL; | |
167 | } | |
168 | EXPORT_SYMBOL_GPL(l2tp_session_find_nth); | |
169 | ||
170 | /* Lookup a tunnel by id | |
171 | */ | |
172 | struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id) | |
173 | { | |
174 | struct l2tp_tunnel *tunnel; | |
175 | struct l2tp_net *pn = l2tp_pernet(net); | |
176 | ||
177 | read_lock_bh(&pn->l2tp_tunnel_list_lock); | |
178 | list_for_each_entry(tunnel, &pn->l2tp_tunnel_list, list) { | |
179 | if (tunnel->tunnel_id == tunnel_id) { | |
180 | read_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
181 | return tunnel; | |
182 | } | |
183 | } | |
184 | read_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
185 | ||
186 | return NULL; | |
187 | } | |
188 | EXPORT_SYMBOL_GPL(l2tp_tunnel_find); | |
189 | ||
190 | struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth) | |
191 | { | |
192 | struct l2tp_net *pn = l2tp_pernet(net); | |
193 | struct l2tp_tunnel *tunnel; | |
194 | int count = 0; | |
195 | ||
196 | read_lock_bh(&pn->l2tp_tunnel_list_lock); | |
197 | list_for_each_entry(tunnel, &pn->l2tp_tunnel_list, list) { | |
198 | if (++count > nth) { | |
199 | read_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
200 | return tunnel; | |
201 | } | |
202 | } | |
203 | ||
204 | read_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
205 | ||
206 | return NULL; | |
207 | } | |
208 | EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); | |
209 | ||
210 | /***************************************************************************** | |
211 | * Receive data handling | |
212 | *****************************************************************************/ | |
213 | ||
214 | /* Queue a skb in order. We come here only if the skb has an L2TP sequence | |
215 | * number. | |
216 | */ | |
217 | static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) | |
218 | { | |
219 | struct sk_buff *skbp; | |
220 | struct sk_buff *tmp; | |
221 | u16 ns = L2TP_SKB_CB(skb)->ns; | |
222 | ||
223 | spin_lock_bh(&session->reorder_q.lock); | |
224 | skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { | |
225 | if (L2TP_SKB_CB(skbp)->ns > ns) { | |
226 | __skb_queue_before(&session->reorder_q, skbp, skb); | |
227 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
228 | "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", | |
229 | session->name, ns, L2TP_SKB_CB(skbp)->ns, | |
230 | skb_queue_len(&session->reorder_q)); | |
231 | session->stats.rx_oos_packets++; | |
232 | goto out; | |
233 | } | |
234 | } | |
235 | ||
236 | __skb_queue_tail(&session->reorder_q, skb); | |
237 | ||
238 | out: | |
239 | spin_unlock_bh(&session->reorder_q.lock); | |
240 | } | |
241 | ||
242 | /* Dequeue a single skb. | |
243 | */ | |
244 | static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) | |
245 | { | |
246 | struct l2tp_tunnel *tunnel = session->tunnel; | |
247 | int length = L2TP_SKB_CB(skb)->length; | |
248 | ||
249 | /* We're about to requeue the skb, so return resources | |
250 | * to its current owner (a socket receive buffer). | |
251 | */ | |
252 | skb_orphan(skb); | |
253 | ||
254 | tunnel->stats.rx_packets++; | |
255 | tunnel->stats.rx_bytes += length; | |
256 | session->stats.rx_packets++; | |
257 | session->stats.rx_bytes += length; | |
258 | ||
259 | if (L2TP_SKB_CB(skb)->has_seq) { | |
260 | /* Bump our Nr */ | |
261 | session->nr++; | |
262 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
263 | "%s: updated nr to %hu\n", session->name, session->nr); | |
264 | } | |
265 | ||
266 | /* call private receive handler */ | |
267 | if (session->recv_skb != NULL) | |
268 | (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); | |
269 | else | |
270 | kfree_skb(skb); | |
271 | ||
272 | if (session->deref) | |
273 | (*session->deref)(session); | |
274 | } | |
275 | ||
276 | /* Dequeue skbs from the session's reorder_q, subject to packet order. | |
277 | * Skbs that have been in the queue for too long are simply discarded. | |
278 | */ | |
279 | static void l2tp_recv_dequeue(struct l2tp_session *session) | |
280 | { | |
281 | struct sk_buff *skb; | |
282 | struct sk_buff *tmp; | |
283 | ||
284 | /* If the pkt at the head of the queue has the nr that we | |
285 | * expect to send up next, dequeue it and any other | |
286 | * in-sequence packets behind it. | |
287 | */ | |
288 | spin_lock_bh(&session->reorder_q.lock); | |
289 | skb_queue_walk_safe(&session->reorder_q, skb, tmp) { | |
290 | if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { | |
291 | session->stats.rx_seq_discards++; | |
292 | session->stats.rx_errors++; | |
293 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
294 | "%s: oos pkt %hu len %d discarded (too old), " | |
295 | "waiting for %hu, reorder_q_len=%d\n", | |
296 | session->name, L2TP_SKB_CB(skb)->ns, | |
297 | L2TP_SKB_CB(skb)->length, session->nr, | |
298 | skb_queue_len(&session->reorder_q)); | |
299 | __skb_unlink(skb, &session->reorder_q); | |
300 | kfree_skb(skb); | |
301 | if (session->deref) | |
302 | (*session->deref)(session); | |
303 | continue; | |
304 | } | |
305 | ||
306 | if (L2TP_SKB_CB(skb)->has_seq) { | |
307 | if (L2TP_SKB_CB(skb)->ns != session->nr) { | |
308 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
309 | "%s: holding oos pkt %hu len %d, " | |
310 | "waiting for %hu, reorder_q_len=%d\n", | |
311 | session->name, L2TP_SKB_CB(skb)->ns, | |
312 | L2TP_SKB_CB(skb)->length, session->nr, | |
313 | skb_queue_len(&session->reorder_q)); | |
314 | goto out; | |
315 | } | |
316 | } | |
317 | __skb_unlink(skb, &session->reorder_q); | |
318 | ||
319 | /* Process the skb. We release the queue lock while we | |
320 | * do so to let other contexts process the queue. | |
321 | */ | |
322 | spin_unlock_bh(&session->reorder_q.lock); | |
323 | l2tp_recv_dequeue_skb(session, skb); | |
324 | spin_lock_bh(&session->reorder_q.lock); | |
325 | } | |
326 | ||
327 | out: | |
328 | spin_unlock_bh(&session->reorder_q.lock); | |
329 | } | |
330 | ||
331 | static inline int l2tp_verify_udp_checksum(struct sock *sk, | |
332 | struct sk_buff *skb) | |
333 | { | |
334 | struct udphdr *uh = udp_hdr(skb); | |
335 | u16 ulen = ntohs(uh->len); | |
336 | struct inet_sock *inet; | |
337 | __wsum psum; | |
338 | ||
339 | if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check) | |
340 | return 0; | |
341 | ||
342 | inet = inet_sk(sk); | |
343 | psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen, | |
344 | IPPROTO_UDP, 0); | |
345 | ||
346 | if ((skb->ip_summed == CHECKSUM_COMPLETE) && | |
347 | !csum_fold(csum_add(psum, skb->csum))) | |
348 | return 0; | |
349 | ||
350 | skb->csum = psum; | |
351 | ||
352 | return __skb_checksum_complete(skb); | |
353 | } | |
354 | ||
355 | /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame | |
356 | * here. The skb is not on a list when we get here. | |
357 | * Returns 0 if the packet was a data packet and was successfully passed on. | |
358 | * Returns 1 if the packet was not a good data packet and could not be | |
359 | * forwarded. All such packets are passed up to userspace to deal with. | |
360 | */ | |
361 | int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, | |
362 | int (*payload_hook)(struct sk_buff *skb)) | |
363 | { | |
364 | struct l2tp_session *session = NULL; | |
365 | unsigned char *ptr, *optr; | |
366 | u16 hdrflags; | |
367 | u32 tunnel_id, session_id; | |
368 | int length; | |
369 | int offset; | |
370 | u16 version; | |
371 | u16 ns, nr; | |
372 | ||
373 | if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb)) | |
374 | goto discard_bad_csum; | |
375 | ||
376 | /* UDP always verifies the packet length. */ | |
377 | __skb_pull(skb, sizeof(struct udphdr)); | |
378 | ||
379 | /* Short packet? */ | |
380 | if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { | |
381 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, | |
382 | "%s: recv short packet (len=%d)\n", tunnel->name, skb->len); | |
383 | goto error; | |
384 | } | |
385 | ||
386 | /* Point to L2TP header */ | |
387 | optr = ptr = skb->data; | |
388 | ||
389 | /* Trace packet contents, if enabled */ | |
390 | if (tunnel->debug & L2TP_MSG_DATA) { | |
391 | length = min(32u, skb->len); | |
392 | if (!pskb_may_pull(skb, length)) | |
393 | goto error; | |
394 | ||
395 | printk(KERN_DEBUG "%s: recv: ", tunnel->name); | |
396 | ||
397 | offset = 0; | |
398 | do { | |
399 | printk(" %02X", ptr[offset]); | |
400 | } while (++offset < length); | |
401 | ||
402 | printk("\n"); | |
403 | } | |
404 | ||
405 | /* Get L2TP header flags */ | |
406 | hdrflags = ntohs(*(__be16 *)ptr); | |
407 | ||
408 | /* Check protocol version */ | |
409 | version = hdrflags & L2TP_HDR_VER_MASK; | |
410 | if (version != tunnel->version) { | |
411 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, | |
412 | "%s: recv protocol version mismatch: got %d expected %d\n", | |
413 | tunnel->name, version, tunnel->version); | |
414 | goto error; | |
415 | } | |
416 | ||
417 | /* Get length of L2TP packet */ | |
418 | length = skb->len; | |
419 | ||
420 | /* If type is control packet, it is handled by userspace. */ | |
421 | if (hdrflags & L2TP_HDRFLAG_T) { | |
422 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, | |
423 | "%s: recv control packet, len=%d\n", tunnel->name, length); | |
424 | goto error; | |
425 | } | |
426 | ||
427 | /* Skip flags */ | |
428 | ptr += 2; | |
429 | ||
430 | /* If length is present, skip it */ | |
431 | if (hdrflags & L2TP_HDRFLAG_L) | |
432 | ptr += 2; | |
433 | ||
434 | /* Extract tunnel and session ID */ | |
435 | tunnel_id = ntohs(*(__be16 *) ptr); | |
436 | ptr += 2; | |
437 | session_id = ntohs(*(__be16 *) ptr); | |
438 | ptr += 2; | |
439 | ||
440 | /* Find the session context */ | |
441 | session = l2tp_session_find(tunnel, session_id); | |
442 | if (!session) { | |
443 | /* Not found? Pass to userspace to deal with */ | |
444 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, | |
445 | "%s: no session found (%hu/%hu). Passing up.\n", | |
446 | tunnel->name, tunnel_id, session_id); | |
447 | goto error; | |
448 | } | |
449 | ||
450 | /* The ref count is increased since we now hold a pointer to | |
451 | * the session. Take care to decrement the refcnt when exiting | |
452 | * this function from now on... | |
453 | */ | |
454 | l2tp_session_inc_refcount(session); | |
455 | if (session->ref) | |
456 | (*session->ref)(session); | |
457 | ||
458 | /* Handle the optional sequence numbers. Sequence numbers are | |
459 | * in different places for L2TPv2 and L2TPv3. | |
460 | * | |
461 | * If we are the LAC, enable/disable sequence numbers under | |
462 | * the control of the LNS. If no sequence numbers present but | |
463 | * we were expecting them, discard frame. | |
464 | */ | |
465 | ns = nr = 0; | |
466 | L2TP_SKB_CB(skb)->has_seq = 0; | |
467 | if (hdrflags & L2TP_HDRFLAG_S) { | |
468 | ns = (u16) ntohs(*(__be16 *) ptr); | |
469 | ptr += 2; | |
470 | nr = ntohs(*(__be16 *) ptr); | |
471 | ptr += 2; | |
472 | ||
473 | /* Store L2TP info in the skb */ | |
474 | L2TP_SKB_CB(skb)->ns = ns; | |
475 | L2TP_SKB_CB(skb)->has_seq = 1; | |
476 | ||
477 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
478 | "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n", | |
479 | session->name, ns, nr, session->nr); | |
480 | } | |
481 | ||
482 | if (L2TP_SKB_CB(skb)->has_seq) { | |
483 | /* Received a packet with sequence numbers. If we're the LNS, | |
484 | * check if we sre sending sequence numbers and if not, | |
485 | * configure it so. | |
486 | */ | |
487 | if ((!session->lns_mode) && (!session->send_seq)) { | |
488 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, | |
489 | "%s: requested to enable seq numbers by LNS\n", | |
490 | session->name); | |
491 | session->send_seq = -1; | |
492 | } | |
493 | } else { | |
494 | /* No sequence numbers. | |
495 | * If user has configured mandatory sequence numbers, discard. | |
496 | */ | |
497 | if (session->recv_seq) { | |
498 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, | |
499 | "%s: recv data has no seq numbers when required. " | |
500 | "Discarding\n", session->name); | |
501 | session->stats.rx_seq_discards++; | |
502 | goto discard; | |
503 | } | |
504 | ||
505 | /* If we're the LAC and we're sending sequence numbers, the | |
506 | * LNS has requested that we no longer send sequence numbers. | |
507 | * If we're the LNS and we're sending sequence numbers, the | |
508 | * LAC is broken. Discard the frame. | |
509 | */ | |
510 | if ((!session->lns_mode) && (session->send_seq)) { | |
511 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, | |
512 | "%s: requested to disable seq numbers by LNS\n", | |
513 | session->name); | |
514 | session->send_seq = 0; | |
515 | } else if (session->send_seq) { | |
516 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, | |
517 | "%s: recv data has no seq numbers when required. " | |
518 | "Discarding\n", session->name); | |
519 | session->stats.rx_seq_discards++; | |
520 | goto discard; | |
521 | } | |
522 | } | |
523 | ||
524 | /* If offset bit set, skip it. */ | |
525 | if (hdrflags & L2TP_HDRFLAG_O) { | |
526 | offset = ntohs(*(__be16 *)ptr); | |
527 | ptr += 2 + offset; | |
528 | } | |
529 | ||
530 | offset = ptr - optr; | |
531 | if (!pskb_may_pull(skb, offset)) | |
532 | goto discard; | |
533 | ||
534 | __skb_pull(skb, offset); | |
535 | ||
536 | /* If caller wants to process the payload before we queue the | |
537 | * packet, do so now. | |
538 | */ | |
539 | if (payload_hook) | |
540 | if ((*payload_hook)(skb)) | |
541 | goto discard; | |
542 | ||
543 | /* Prepare skb for adding to the session's reorder_q. Hold | |
544 | * packets for max reorder_timeout or 1 second if not | |
545 | * reordering. | |
546 | */ | |
547 | L2TP_SKB_CB(skb)->length = length; | |
548 | L2TP_SKB_CB(skb)->expires = jiffies + | |
549 | (session->reorder_timeout ? session->reorder_timeout : HZ); | |
550 | ||
551 | /* Add packet to the session's receive queue. Reordering is done here, if | |
552 | * enabled. Saved L2TP protocol info is stored in skb->sb[]. | |
553 | */ | |
554 | if (L2TP_SKB_CB(skb)->has_seq) { | |
555 | if (session->reorder_timeout != 0) { | |
556 | /* Packet reordering enabled. Add skb to session's | |
557 | * reorder queue, in order of ns. | |
558 | */ | |
559 | l2tp_recv_queue_skb(session, skb); | |
560 | } else { | |
561 | /* Packet reordering disabled. Discard out-of-sequence | |
562 | * packets | |
563 | */ | |
564 | if (L2TP_SKB_CB(skb)->ns != session->nr) { | |
565 | session->stats.rx_seq_discards++; | |
566 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
567 | "%s: oos pkt %hu len %d discarded, " | |
568 | "waiting for %hu, reorder_q_len=%d\n", | |
569 | session->name, L2TP_SKB_CB(skb)->ns, | |
570 | L2TP_SKB_CB(skb)->length, session->nr, | |
571 | skb_queue_len(&session->reorder_q)); | |
572 | goto discard; | |
573 | } | |
574 | skb_queue_tail(&session->reorder_q, skb); | |
575 | } | |
576 | } else { | |
577 | /* No sequence numbers. Add the skb to the tail of the | |
578 | * reorder queue. This ensures that it will be | |
579 | * delivered after all previous sequenced skbs. | |
580 | */ | |
581 | skb_queue_tail(&session->reorder_q, skb); | |
582 | } | |
583 | ||
584 | /* Try to dequeue as many skbs from reorder_q as we can. */ | |
585 | l2tp_recv_dequeue(session); | |
586 | ||
587 | l2tp_session_dec_refcount(session); | |
588 | ||
589 | return 0; | |
590 | ||
591 | discard: | |
592 | session->stats.rx_errors++; | |
593 | kfree_skb(skb); | |
594 | ||
595 | if (session->deref) | |
596 | (*session->deref)(session); | |
597 | ||
598 | l2tp_session_dec_refcount(session); | |
599 | ||
600 | return 0; | |
601 | ||
602 | discard_bad_csum: | |
603 | LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); | |
604 | UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0); | |
605 | tunnel->stats.rx_errors++; | |
606 | kfree_skb(skb); | |
607 | ||
608 | return 0; | |
609 | ||
610 | error: | |
611 | /* Put UDP header back */ | |
612 | __skb_push(skb, sizeof(struct udphdr)); | |
613 | ||
614 | return 1; | |
615 | } | |
616 | EXPORT_SYMBOL_GPL(l2tp_udp_recv_core); | |
617 | ||
618 | /* UDP encapsulation receive handler. See net/ipv4/udp.c. | |
619 | * Return codes: | |
620 | * 0 : success. | |
621 | * <0: error | |
622 | * >0: skb should be passed up to userspace as UDP. | |
623 | */ | |
624 | int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) | |
625 | { | |
626 | struct l2tp_tunnel *tunnel; | |
627 | ||
628 | tunnel = l2tp_sock_to_tunnel(sk); | |
629 | if (tunnel == NULL) | |
630 | goto pass_up; | |
631 | ||
632 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, | |
633 | "%s: received %d bytes\n", tunnel->name, skb->len); | |
634 | ||
635 | if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) | |
636 | goto pass_up_put; | |
637 | ||
638 | sock_put(sk); | |
639 | return 0; | |
640 | ||
641 | pass_up_put: | |
642 | sock_put(sk); | |
643 | pass_up: | |
644 | return 1; | |
645 | } | |
646 | EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); | |
647 | ||
648 | /************************************************************************ | |
649 | * Transmit handling | |
650 | ***********************************************************************/ | |
651 | ||
652 | /* Build an L2TP header for the session into the buffer provided. | |
653 | */ | |
654 | static void l2tp_build_l2tpv2_header(struct l2tp_tunnel *tunnel, | |
655 | struct l2tp_session *session, | |
656 | void *buf) | |
657 | { | |
658 | __be16 *bufp = buf; | |
659 | u16 flags = L2TP_HDR_VER_2; | |
660 | u32 tunnel_id = tunnel->peer_tunnel_id; | |
661 | u32 session_id = session->peer_session_id; | |
662 | ||
663 | if (session->send_seq) | |
664 | flags |= L2TP_HDRFLAG_S; | |
665 | ||
666 | /* Setup L2TP header. */ | |
667 | *bufp++ = htons(flags); | |
668 | *bufp++ = htons(tunnel_id); | |
669 | *bufp++ = htons(session_id); | |
670 | if (session->send_seq) { | |
671 | *bufp++ = htons(session->ns); | |
672 | *bufp++ = 0; | |
673 | session->ns++; | |
674 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, | |
675 | "%s: updated ns to %hu\n", session->name, session->ns); | |
676 | } | |
677 | } | |
678 | ||
679 | void l2tp_build_l2tp_header(struct l2tp_session *session, void *buf) | |
680 | { | |
681 | struct l2tp_tunnel *tunnel = session->tunnel; | |
682 | ||
683 | BUG_ON(tunnel->version != L2TP_HDR_VER_2); | |
684 | l2tp_build_l2tpv2_header(tunnel, session, buf); | |
685 | } | |
686 | EXPORT_SYMBOL_GPL(l2tp_build_l2tp_header); | |
687 | ||
688 | int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len) | |
689 | { | |
690 | struct l2tp_tunnel *tunnel = session->tunnel; | |
691 | unsigned int len = skb->len; | |
692 | int error; | |
693 | ||
694 | /* Debug */ | |
695 | if (session->send_seq) | |
696 | PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, | |
697 | "%s: send %Zd bytes, ns=%hu\n", session->name, | |
698 | data_len, session->ns - 1); | |
699 | else | |
700 | PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, | |
701 | "%s: send %Zd bytes\n", session->name, data_len); | |
702 | ||
703 | if (session->debug & L2TP_MSG_DATA) { | |
704 | int i; | |
705 | unsigned char *datap = skb->data + sizeof(struct udphdr); | |
706 | ||
707 | printk(KERN_DEBUG "%s: xmit:", session->name); | |
708 | for (i = 0; i < (len - sizeof(struct udphdr)); i++) { | |
709 | printk(" %02X", *datap++); | |
710 | if (i == 31) { | |
711 | printk(" ..."); | |
712 | break; | |
713 | } | |
714 | } | |
715 | printk("\n"); | |
716 | } | |
717 | ||
718 | /* Queue the packet to IP for output */ | |
719 | error = ip_queue_xmit(skb, 1); | |
720 | ||
721 | /* Update stats */ | |
722 | if (error >= 0) { | |
723 | tunnel->stats.tx_packets++; | |
724 | tunnel->stats.tx_bytes += len; | |
725 | session->stats.tx_packets++; | |
726 | session->stats.tx_bytes += len; | |
727 | } else { | |
728 | tunnel->stats.tx_errors++; | |
729 | session->stats.tx_errors++; | |
730 | } | |
731 | ||
732 | return 0; | |
733 | } | |
734 | EXPORT_SYMBOL_GPL(l2tp_xmit_core); | |
735 | ||
736 | /* Automatically called when the skb is freed. | |
737 | */ | |
738 | static void l2tp_sock_wfree(struct sk_buff *skb) | |
739 | { | |
740 | sock_put(skb->sk); | |
741 | } | |
742 | ||
743 | /* For data skbs that we transmit, we associate with the tunnel socket | |
744 | * but don't do accounting. | |
745 | */ | |
746 | static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk) | |
747 | { | |
748 | sock_hold(sk); | |
749 | skb->sk = sk; | |
750 | skb->destructor = l2tp_sock_wfree; | |
751 | } | |
752 | ||
753 | /* If caller requires the skb to have a ppp header, the header must be | |
754 | * inserted in the skb data before calling this function. | |
755 | */ | |
756 | int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) | |
757 | { | |
758 | int data_len = skb->len; | |
759 | struct sock *sk = session->tunnel->sock; | |
760 | struct udphdr *uh; | |
761 | unsigned int udp_len; | |
762 | struct inet_sock *inet; | |
763 | __wsum csum; | |
764 | int old_headroom; | |
765 | int new_headroom; | |
766 | int headroom; | |
767 | ||
768 | /* Check that there's enough headroom in the skb to insert IP, | |
769 | * UDP and L2TP headers. If not enough, expand it to | |
770 | * make room. Adjust truesize. | |
771 | */ | |
772 | headroom = NET_SKB_PAD + sizeof(struct iphdr) + | |
773 | sizeof(struct udphdr) + hdr_len; | |
774 | old_headroom = skb_headroom(skb); | |
775 | if (skb_cow_head(skb, headroom)) | |
776 | goto abort; | |
777 | ||
778 | new_headroom = skb_headroom(skb); | |
779 | skb_orphan(skb); | |
780 | skb->truesize += new_headroom - old_headroom; | |
781 | ||
782 | /* Setup L2TP header */ | |
783 | l2tp_build_l2tp_header(session, __skb_push(skb, hdr_len)); | |
784 | udp_len = sizeof(struct udphdr) + hdr_len + data_len; | |
785 | ||
786 | /* Setup UDP header */ | |
787 | inet = inet_sk(sk); | |
788 | __skb_push(skb, sizeof(*uh)); | |
789 | skb_reset_transport_header(skb); | |
790 | uh = udp_hdr(skb); | |
791 | uh->source = inet->inet_sport; | |
792 | uh->dest = inet->inet_dport; | |
793 | uh->len = htons(udp_len); | |
794 | ||
795 | uh->check = 0; | |
796 | ||
797 | memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); | |
798 | IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | | |
799 | IPSKB_REROUTED); | |
800 | nf_reset(skb); | |
801 | ||
802 | /* Get routing info from the tunnel socket */ | |
803 | skb_dst_drop(skb); | |
804 | skb_dst_set(skb, dst_clone(__sk_dst_get(sk))); | |
805 | l2tp_skb_set_owner_w(skb, sk); | |
806 | ||
807 | /* Calculate UDP checksum if configured to do so */ | |
808 | if (sk->sk_no_check == UDP_CSUM_NOXMIT) | |
809 | skb->ip_summed = CHECKSUM_NONE; | |
810 | else if ((skb_dst(skb) && skb_dst(skb)->dev) && | |
811 | (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) { | |
812 | skb->ip_summed = CHECKSUM_COMPLETE; | |
813 | csum = skb_checksum(skb, 0, udp_len, 0); | |
814 | uh->check = csum_tcpudp_magic(inet->inet_saddr, | |
815 | inet->inet_daddr, | |
816 | udp_len, IPPROTO_UDP, csum); | |
817 | if (uh->check == 0) | |
818 | uh->check = CSUM_MANGLED_0; | |
819 | } else { | |
820 | skb->ip_summed = CHECKSUM_PARTIAL; | |
821 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
822 | skb->csum_offset = offsetof(struct udphdr, check); | |
823 | uh->check = ~csum_tcpudp_magic(inet->inet_saddr, | |
824 | inet->inet_daddr, | |
825 | udp_len, IPPROTO_UDP, 0); | |
826 | } | |
827 | ||
828 | l2tp_xmit_core(session, skb, data_len); | |
829 | ||
830 | abort: | |
831 | return 0; | |
832 | } | |
833 | EXPORT_SYMBOL_GPL(l2tp_xmit_skb); | |
834 | ||
835 | /***************************************************************************** | |
836 | * Tinnel and session create/destroy. | |
837 | *****************************************************************************/ | |
838 | ||
839 | /* Tunnel socket destruct hook. | |
840 | * The tunnel context is deleted only when all session sockets have been | |
841 | * closed. | |
842 | */ | |
843 | void l2tp_tunnel_destruct(struct sock *sk) | |
844 | { | |
845 | struct l2tp_tunnel *tunnel; | |
846 | ||
847 | tunnel = sk->sk_user_data; | |
848 | if (tunnel == NULL) | |
849 | goto end; | |
850 | ||
851 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, | |
852 | "%s: closing...\n", tunnel->name); | |
853 | ||
854 | /* Close all sessions */ | |
855 | l2tp_tunnel_closeall(tunnel); | |
856 | ||
857 | /* No longer an encapsulation socket. See net/ipv4/udp.c */ | |
858 | (udp_sk(sk))->encap_type = 0; | |
859 | (udp_sk(sk))->encap_rcv = NULL; | |
860 | ||
861 | /* Remove hooks into tunnel socket */ | |
862 | tunnel->sock = NULL; | |
863 | sk->sk_destruct = tunnel->old_sk_destruct; | |
864 | sk->sk_user_data = NULL; | |
865 | ||
866 | /* Call the original destructor */ | |
867 | if (sk->sk_destruct) | |
868 | (*sk->sk_destruct)(sk); | |
869 | ||
870 | /* We're finished with the socket */ | |
871 | l2tp_tunnel_dec_refcount(tunnel); | |
872 | ||
873 | end: | |
874 | return; | |
875 | } | |
876 | EXPORT_SYMBOL(l2tp_tunnel_destruct); | |
877 | ||
878 | /* When the tunnel is closed, all the attached sessions need to go too. | |
879 | */ | |
880 | void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) | |
881 | { | |
882 | int hash; | |
883 | struct hlist_node *walk; | |
884 | struct hlist_node *tmp; | |
885 | struct l2tp_session *session; | |
886 | ||
887 | BUG_ON(tunnel == NULL); | |
888 | ||
889 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, | |
890 | "%s: closing all sessions...\n", tunnel->name); | |
891 | ||
892 | write_lock_bh(&tunnel->hlist_lock); | |
893 | for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { | |
894 | again: | |
895 | hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { | |
896 | session = hlist_entry(walk, struct l2tp_session, hlist); | |
897 | ||
898 | PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO, | |
899 | "%s: closing session\n", session->name); | |
900 | ||
901 | hlist_del_init(&session->hlist); | |
902 | ||
903 | /* Since we should hold the sock lock while | |
904 | * doing any unbinding, we need to release the | |
905 | * lock we're holding before taking that lock. | |
906 | * Hold a reference to the sock so it doesn't | |
907 | * disappear as we're jumping between locks. | |
908 | */ | |
909 | if (session->ref != NULL) | |
910 | (*session->ref)(session); | |
911 | ||
912 | write_unlock_bh(&tunnel->hlist_lock); | |
913 | ||
914 | if (session->session_close != NULL) | |
915 | (*session->session_close)(session); | |
916 | ||
917 | if (session->deref != NULL) | |
918 | (*session->deref)(session); | |
919 | ||
920 | write_lock_bh(&tunnel->hlist_lock); | |
921 | ||
922 | /* Now restart from the beginning of this hash | |
923 | * chain. We always remove a session from the | |
924 | * list so we are guaranteed to make forward | |
925 | * progress. | |
926 | */ | |
927 | goto again; | |
928 | } | |
929 | } | |
930 | write_unlock_bh(&tunnel->hlist_lock); | |
931 | } | |
932 | EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall); | |
933 | ||
934 | /* Really kill the tunnel. | |
935 | * Come here only when all sessions have been cleared from the tunnel. | |
936 | */ | |
937 | void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) | |
938 | { | |
939 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); | |
940 | ||
941 | BUG_ON(atomic_read(&tunnel->ref_count) != 0); | |
942 | BUG_ON(tunnel->sock != NULL); | |
943 | ||
944 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, | |
945 | "%s: free...\n", tunnel->name); | |
946 | ||
947 | /* Remove from tunnel list */ | |
948 | write_lock_bh(&pn->l2tp_tunnel_list_lock); | |
949 | list_del_init(&tunnel->list); | |
950 | write_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
951 | ||
952 | atomic_dec(&l2tp_tunnel_count); | |
953 | kfree(tunnel); | |
954 | } | |
955 | EXPORT_SYMBOL_GPL(l2tp_tunnel_free); | |
956 | ||
957 | 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) | |
958 | { | |
959 | struct l2tp_tunnel *tunnel = NULL; | |
960 | int err; | |
961 | struct socket *sock = NULL; | |
962 | struct sock *sk = NULL; | |
963 | struct l2tp_net *pn; | |
964 | ||
965 | /* Get the tunnel socket from the fd, which was opened by | |
966 | * the userspace L2TP daemon. | |
967 | */ | |
968 | err = -EBADF; | |
969 | sock = sockfd_lookup(fd, &err); | |
970 | if (!sock) { | |
971 | printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n", | |
972 | tunnel_id, fd, err); | |
973 | goto err; | |
974 | } | |
975 | ||
976 | sk = sock->sk; | |
977 | ||
978 | /* Quick sanity checks */ | |
979 | err = -EPROTONOSUPPORT; | |
980 | if (sk->sk_protocol != IPPROTO_UDP) { | |
981 | printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", | |
982 | tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); | |
983 | goto err; | |
984 | } | |
985 | err = -EAFNOSUPPORT; | |
986 | if (sock->ops->family != AF_INET) { | |
987 | printk(KERN_ERR "tunl %hu: fd %d wrong family, got %d, expected %d\n", | |
988 | tunnel_id, fd, sock->ops->family, AF_INET); | |
989 | goto err; | |
990 | } | |
991 | ||
992 | /* Check if this socket has already been prepped */ | |
993 | tunnel = (struct l2tp_tunnel *)sk->sk_user_data; | |
994 | if (tunnel != NULL) { | |
995 | /* This socket has already been prepped */ | |
996 | err = -EBUSY; | |
997 | goto err; | |
998 | } | |
999 | ||
1000 | if (version != L2TP_HDR_VER_2) | |
1001 | goto err; | |
1002 | ||
1003 | tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); | |
1004 | if (tunnel == NULL) { | |
1005 | err = -ENOMEM; | |
1006 | goto err; | |
1007 | } | |
1008 | ||
1009 | tunnel->version = version; | |
1010 | tunnel->tunnel_id = tunnel_id; | |
1011 | tunnel->peer_tunnel_id = peer_tunnel_id; | |
1012 | tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; | |
1013 | ||
1014 | tunnel->magic = L2TP_TUNNEL_MAGIC; | |
1015 | sprintf(&tunnel->name[0], "tunl %u", tunnel_id); | |
1016 | rwlock_init(&tunnel->hlist_lock); | |
1017 | ||
1018 | /* The net we belong to */ | |
1019 | tunnel->l2tp_net = net; | |
1020 | pn = l2tp_pernet(net); | |
1021 | ||
1022 | if (cfg) | |
1023 | tunnel->debug = cfg->debug; | |
1024 | ||
1025 | /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ | |
1026 | udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; | |
1027 | udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv; | |
1028 | ||
1029 | sk->sk_user_data = tunnel; | |
1030 | ||
1031 | /* Hook on the tunnel socket destructor so that we can cleanup | |
1032 | * if the tunnel socket goes away. | |
1033 | */ | |
1034 | tunnel->old_sk_destruct = sk->sk_destruct; | |
1035 | sk->sk_destruct = &l2tp_tunnel_destruct; | |
1036 | tunnel->sock = sk; | |
1037 | sk->sk_allocation = GFP_ATOMIC; | |
1038 | ||
1039 | /* Add tunnel to our list */ | |
1040 | INIT_LIST_HEAD(&tunnel->list); | |
1041 | write_lock_bh(&pn->l2tp_tunnel_list_lock); | |
1042 | list_add(&tunnel->list, &pn->l2tp_tunnel_list); | |
1043 | write_unlock_bh(&pn->l2tp_tunnel_list_lock); | |
1044 | atomic_inc(&l2tp_tunnel_count); | |
1045 | ||
1046 | /* Bump the reference count. The tunnel context is deleted | |
1047 | * only when this drops to zero. | |
1048 | */ | |
1049 | l2tp_tunnel_inc_refcount(tunnel); | |
1050 | ||
1051 | err = 0; | |
1052 | err: | |
1053 | if (tunnelp) | |
1054 | *tunnelp = tunnel; | |
1055 | ||
1056 | if (sock) | |
1057 | sockfd_put(sock); | |
1058 | ||
1059 | return err; | |
1060 | } | |
1061 | EXPORT_SYMBOL_GPL(l2tp_tunnel_create); | |
1062 | ||
1063 | /* Really kill the session. | |
1064 | */ | |
1065 | void l2tp_session_free(struct l2tp_session *session) | |
1066 | { | |
1067 | struct l2tp_tunnel *tunnel; | |
1068 | ||
1069 | BUG_ON(atomic_read(&session->ref_count) != 0); | |
1070 | ||
1071 | tunnel = session->tunnel; | |
1072 | if (tunnel != NULL) { | |
1073 | BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); | |
1074 | ||
1075 | /* Delete the session from the hash */ | |
1076 | write_lock_bh(&tunnel->hlist_lock); | |
1077 | hlist_del_init(&session->hlist); | |
1078 | write_unlock_bh(&tunnel->hlist_lock); | |
1079 | ||
1080 | if (session->session_id != 0) | |
1081 | atomic_dec(&l2tp_session_count); | |
1082 | ||
1083 | sock_put(tunnel->sock); | |
1084 | ||
1085 | /* This will delete the tunnel context if this | |
1086 | * is the last session on the tunnel. | |
1087 | */ | |
1088 | session->tunnel = NULL; | |
1089 | l2tp_tunnel_dec_refcount(tunnel); | |
1090 | } | |
1091 | ||
1092 | kfree(session); | |
1093 | ||
1094 | return; | |
1095 | } | |
1096 | EXPORT_SYMBOL_GPL(l2tp_session_free); | |
1097 | ||
1098 | 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) | |
1099 | { | |
1100 | struct l2tp_session *session; | |
1101 | ||
1102 | session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); | |
1103 | if (session != NULL) { | |
1104 | session->magic = L2TP_SESSION_MAGIC; | |
1105 | session->tunnel = tunnel; | |
1106 | ||
1107 | session->session_id = session_id; | |
1108 | session->peer_session_id = peer_session_id; | |
1109 | ||
1110 | sprintf(&session->name[0], "sess %u/%u", | |
1111 | tunnel->tunnel_id, session->session_id); | |
1112 | ||
1113 | skb_queue_head_init(&session->reorder_q); | |
1114 | ||
1115 | INIT_HLIST_NODE(&session->hlist); | |
1116 | ||
1117 | /* Inherit debug options from tunnel */ | |
1118 | session->debug = tunnel->debug; | |
1119 | ||
1120 | if (cfg) { | |
1121 | session->debug = cfg->debug; | |
1122 | session->hdr_len = cfg->hdr_len; | |
1123 | session->mtu = cfg->mtu; | |
1124 | session->mru = cfg->mru; | |
1125 | session->send_seq = cfg->send_seq; | |
1126 | session->recv_seq = cfg->recv_seq; | |
1127 | session->lns_mode = cfg->lns_mode; | |
1128 | } | |
1129 | ||
1130 | /* Bump the reference count. The session context is deleted | |
1131 | * only when this drops to zero. | |
1132 | */ | |
1133 | l2tp_session_inc_refcount(session); | |
1134 | l2tp_tunnel_inc_refcount(tunnel); | |
1135 | ||
1136 | /* Ensure tunnel socket isn't deleted */ | |
1137 | sock_hold(tunnel->sock); | |
1138 | ||
1139 | /* Add session to the tunnel's hash list */ | |
1140 | write_lock_bh(&tunnel->hlist_lock); | |
1141 | hlist_add_head(&session->hlist, | |
1142 | l2tp_session_id_hash(tunnel, session_id)); | |
1143 | write_unlock_bh(&tunnel->hlist_lock); | |
1144 | ||
1145 | /* Ignore management session in session count value */ | |
1146 | if (session->session_id != 0) | |
1147 | atomic_inc(&l2tp_session_count); | |
1148 | } | |
1149 | ||
1150 | return session; | |
1151 | } | |
1152 | EXPORT_SYMBOL_GPL(l2tp_session_create); | |
1153 | ||
1154 | /***************************************************************************** | |
1155 | * Init and cleanup | |
1156 | *****************************************************************************/ | |
1157 | ||
1158 | static __net_init int l2tp_init_net(struct net *net) | |
1159 | { | |
1160 | struct l2tp_net *pn; | |
1161 | int err; | |
1162 | ||
1163 | pn = kzalloc(sizeof(*pn), GFP_KERNEL); | |
1164 | if (!pn) | |
1165 | return -ENOMEM; | |
1166 | ||
1167 | INIT_LIST_HEAD(&pn->l2tp_tunnel_list); | |
1168 | rwlock_init(&pn->l2tp_tunnel_list_lock); | |
1169 | ||
1170 | err = net_assign_generic(net, l2tp_net_id, pn); | |
1171 | if (err) | |
1172 | goto out; | |
1173 | ||
1174 | return 0; | |
1175 | ||
1176 | out: | |
1177 | kfree(pn); | |
1178 | return err; | |
1179 | } | |
1180 | ||
1181 | static __net_exit void l2tp_exit_net(struct net *net) | |
1182 | { | |
1183 | struct l2tp_net *pn; | |
1184 | ||
1185 | pn = net_generic(net, l2tp_net_id); | |
1186 | /* | |
1187 | * if someone has cached our net then | |
1188 | * further net_generic call will return NULL | |
1189 | */ | |
1190 | net_assign_generic(net, l2tp_net_id, NULL); | |
1191 | kfree(pn); | |
1192 | } | |
1193 | ||
1194 | static struct pernet_operations l2tp_net_ops = { | |
1195 | .init = l2tp_init_net, | |
1196 | .exit = l2tp_exit_net, | |
1197 | .id = &l2tp_net_id, | |
1198 | .size = sizeof(struct l2tp_net), | |
1199 | }; | |
1200 | ||
1201 | static int __init l2tp_init(void) | |
1202 | { | |
1203 | int rc = 0; | |
1204 | ||
1205 | rc = register_pernet_device(&l2tp_net_ops); | |
1206 | if (rc) | |
1207 | goto out; | |
1208 | ||
1209 | printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION); | |
1210 | ||
1211 | out: | |
1212 | return rc; | |
1213 | } | |
1214 | ||
1215 | static void __exit l2tp_exit(void) | |
1216 | { | |
1217 | unregister_pernet_device(&l2tp_net_ops); | |
1218 | } | |
1219 | ||
1220 | module_init(l2tp_init); | |
1221 | module_exit(l2tp_exit); | |
1222 | ||
1223 | MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); | |
1224 | MODULE_DESCRIPTION("L2TP core"); | |
1225 | MODULE_LICENSE("GPL"); | |
1226 | MODULE_VERSION(L2TP_DRV_VERSION); | |
1227 |