4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
6 * This file contains some code of the original L2TPv2 pppol2tp
7 * driver, which has the following copyright:
9 * Authors: Martijn van Oosterhout <kleptog@svana.org>
10 * James Chapman (jchapman@katalix.com)
12 * Michal Ostrowski <mostrows@speakeasy.net>
13 * Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
14 * David S. Miller (davem@redhat.com)
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.
21 #include <linux/module.h>
22 #include <linux/string.h>
23 #include <linux/list.h>
24 #include <linux/rculist.h>
25 #include <linux/uaccess.h>
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>
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>
42 #include <linux/udp.h>
43 #include <linux/l2tp.h>
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>
53 #include <net/inet_common.h>
55 #include <net/protocol.h>
57 #include <asm/byteorder.h>
58 #include <linux/atomic.h>
60 #include "l2tp_core.h"
62 #define L2TP_DRV_VERSION "V2.0"
64 /* L2TP header constants */
65 #define L2TP_HDRFLAG_T 0x8000
66 #define L2TP_HDRFLAG_L 0x4000
67 #define L2TP_HDRFLAG_S 0x0800
68 #define L2TP_HDRFLAG_O 0x0200
69 #define L2TP_HDRFLAG_P 0x0100
71 #define L2TP_HDR_VER_MASK 0x000F
72 #define L2TP_HDR_VER_2 0x0002
73 #define L2TP_HDR_VER_3 0x0003
75 /* L2TPv3 default L2-specific sublayer */
76 #define L2TP_SLFLAG_S 0x40000000
77 #define L2TP_SL_SEQ_MASK 0x00ffffff
79 #define L2TP_HDR_SIZE_SEQ 10
80 #define L2TP_HDR_SIZE_NOSEQ 6
82 /* Default trace flags */
83 #define L2TP_DEFAULT_DEBUG_FLAGS 0
85 #define PRINTK(_mask, _type, _lvl, _fmt, args...) \
87 if ((_mask) & (_type)) \
88 printk(_lvl "L2TP: " _fmt, ##args); \
91 /* Private data stored for received packets in the skb.
97 unsigned long expires;
100 #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
102 static atomic_t l2tp_tunnel_count;
103 static atomic_t l2tp_session_count;
105 /* per-net private data for this module */
106 static unsigned int l2tp_net_id;
108 struct list_head l2tp_tunnel_list;
109 spinlock_t l2tp_tunnel_list_lock;
110 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
111 spinlock_t l2tp_session_hlist_lock;
114 static void l2tp_session_set_header_len(struct l2tp_session *session, int version);
115 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
116 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
118 static inline struct l2tp_net *l2tp_pernet(struct net *net)
122 return net_generic(net, l2tp_net_id);
126 /* Tunnel reference counts. Incremented per session that is added to
129 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
131 atomic_inc(&tunnel->ref_count);
134 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
136 if (atomic_dec_and_test(&tunnel->ref_count))
137 l2tp_tunnel_free(tunnel);
139 #ifdef L2TP_REFCNT_DEBUG
140 #define l2tp_tunnel_inc_refcount(_t) do { \
141 printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
142 l2tp_tunnel_inc_refcount_1(_t); \
144 #define l2tp_tunnel_dec_refcount(_t) do { \
145 printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
146 l2tp_tunnel_dec_refcount_1(_t); \
149 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
150 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
153 /* Session hash global list for L2TPv3.
154 * The session_id SHOULD be random according to RFC3931, but several
155 * L2TP implementations use incrementing session_ids. So we do a real
156 * hash on the session_id, rather than a simple bitmask.
158 static inline struct hlist_head *
159 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
161 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
165 /* Lookup a session by id in the global session list
167 static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
169 struct l2tp_net *pn = l2tp_pernet(net);
170 struct hlist_head *session_list =
171 l2tp_session_id_hash_2(pn, session_id);
172 struct l2tp_session *session;
173 struct hlist_node *walk;
176 hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
177 if (session->session_id == session_id) {
178 rcu_read_unlock_bh();
182 rcu_read_unlock_bh();
187 /* Session hash list.
188 * The session_id SHOULD be random according to RFC2661, but several
189 * L2TP implementations (Cisco and Microsoft) use incrementing
190 * session_ids. So we do a real hash on the session_id, rather than a
193 static inline struct hlist_head *
194 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
196 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
199 /* Lookup a session by id
201 struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
203 struct hlist_head *session_list;
204 struct l2tp_session *session;
205 struct hlist_node *walk;
207 /* In L2TPv3, session_ids are unique over all tunnels and we
208 * sometimes need to look them up before we know the
212 return l2tp_session_find_2(net, session_id);
214 session_list = l2tp_session_id_hash(tunnel, session_id);
215 read_lock_bh(&tunnel->hlist_lock);
216 hlist_for_each_entry(session, walk, session_list, hlist) {
217 if (session->session_id == session_id) {
218 read_unlock_bh(&tunnel->hlist_lock);
222 read_unlock_bh(&tunnel->hlist_lock);
226 EXPORT_SYMBOL_GPL(l2tp_session_find);
228 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth)
231 struct hlist_node *walk;
232 struct l2tp_session *session;
235 read_lock_bh(&tunnel->hlist_lock);
236 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
237 hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) {
239 read_unlock_bh(&tunnel->hlist_lock);
245 read_unlock_bh(&tunnel->hlist_lock);
249 EXPORT_SYMBOL_GPL(l2tp_session_find_nth);
251 /* Lookup a session by interface name.
252 * This is very inefficient but is only used by management interfaces.
254 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname)
256 struct l2tp_net *pn = l2tp_pernet(net);
258 struct hlist_node *walk;
259 struct l2tp_session *session;
262 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
263 hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
264 if (!strcmp(session->ifname, ifname)) {
265 rcu_read_unlock_bh();
271 rcu_read_unlock_bh();
275 EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname);
277 /* Lookup a tunnel by id
279 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
281 struct l2tp_tunnel *tunnel;
282 struct l2tp_net *pn = l2tp_pernet(net);
285 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
286 if (tunnel->tunnel_id == tunnel_id) {
287 rcu_read_unlock_bh();
291 rcu_read_unlock_bh();
295 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
297 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
299 struct l2tp_net *pn = l2tp_pernet(net);
300 struct l2tp_tunnel *tunnel;
304 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
306 rcu_read_unlock_bh();
311 rcu_read_unlock_bh();
315 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
317 /*****************************************************************************
318 * Receive data handling
319 *****************************************************************************/
321 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
324 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
326 struct sk_buff *skbp;
328 u32 ns = L2TP_SKB_CB(skb)->ns;
330 spin_lock_bh(&session->reorder_q.lock);
331 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
332 if (L2TP_SKB_CB(skbp)->ns > ns) {
333 __skb_queue_before(&session->reorder_q, skbp, skb);
334 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
335 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
336 session->name, ns, L2TP_SKB_CB(skbp)->ns,
337 skb_queue_len(&session->reorder_q));
338 session->stats.rx_oos_packets++;
343 __skb_queue_tail(&session->reorder_q, skb);
346 spin_unlock_bh(&session->reorder_q.lock);
349 /* Dequeue a single skb.
351 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
353 struct l2tp_tunnel *tunnel = session->tunnel;
354 int length = L2TP_SKB_CB(skb)->length;
356 /* We're about to requeue the skb, so return resources
357 * to its current owner (a socket receive buffer).
361 tunnel->stats.rx_packets++;
362 tunnel->stats.rx_bytes += length;
363 session->stats.rx_packets++;
364 session->stats.rx_bytes += length;
366 if (L2TP_SKB_CB(skb)->has_seq) {
369 if (tunnel->version == L2TP_HDR_VER_2)
370 session->nr &= 0xffff;
372 session->nr &= 0xffffff;
374 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
375 "%s: updated nr to %hu\n", session->name, session->nr);
378 /* call private receive handler */
379 if (session->recv_skb != NULL)
380 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
385 (*session->deref)(session);
388 /* Dequeue skbs from the session's reorder_q, subject to packet order.
389 * Skbs that have been in the queue for too long are simply discarded.
391 static void l2tp_recv_dequeue(struct l2tp_session *session)
396 /* If the pkt at the head of the queue has the nr that we
397 * expect to send up next, dequeue it and any other
398 * in-sequence packets behind it.
400 spin_lock_bh(&session->reorder_q.lock);
401 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
402 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
403 session->stats.rx_seq_discards++;
404 session->stats.rx_errors++;
405 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
406 "%s: oos pkt %u len %d discarded (too old), "
407 "waiting for %u, reorder_q_len=%d\n",
408 session->name, L2TP_SKB_CB(skb)->ns,
409 L2TP_SKB_CB(skb)->length, session->nr,
410 skb_queue_len(&session->reorder_q));
411 __skb_unlink(skb, &session->reorder_q);
414 (*session->deref)(session);
418 if (L2TP_SKB_CB(skb)->has_seq) {
419 if (L2TP_SKB_CB(skb)->ns != session->nr) {
420 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
421 "%s: holding oos pkt %u len %d, "
422 "waiting for %u, reorder_q_len=%d\n",
423 session->name, L2TP_SKB_CB(skb)->ns,
424 L2TP_SKB_CB(skb)->length, session->nr,
425 skb_queue_len(&session->reorder_q));
429 __skb_unlink(skb, &session->reorder_q);
431 /* Process the skb. We release the queue lock while we
432 * do so to let other contexts process the queue.
434 spin_unlock_bh(&session->reorder_q.lock);
435 l2tp_recv_dequeue_skb(session, skb);
436 spin_lock_bh(&session->reorder_q.lock);
440 spin_unlock_bh(&session->reorder_q.lock);
443 static inline int l2tp_verify_udp_checksum(struct sock *sk,
446 struct udphdr *uh = udp_hdr(skb);
447 u16 ulen = ntohs(uh->len);
448 struct inet_sock *inet;
451 if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
455 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
458 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
459 !csum_fold(csum_add(psum, skb->csum)))
464 return __skb_checksum_complete(skb);
467 /* Do receive processing of L2TP data frames. We handle both L2TPv2
468 * and L2TPv3 data frames here.
470 * L2TPv2 Data Message Header
473 * 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
474 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
475 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
476 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
477 * | Tunnel ID | Session ID |
478 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
479 * | Ns (opt) | Nr (opt) |
480 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
481 * | Offset Size (opt) | Offset pad... (opt)
482 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
484 * Data frames are marked by T=0. All other fields are the same as
485 * those in L2TP control frames.
487 * L2TPv3 Data Message Header
489 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
490 * | L2TP Session Header |
491 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
492 * | L2-Specific Sublayer |
493 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
494 * | Tunnel Payload ...
495 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
497 * L2TPv3 Session Header Over IP
500 * 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
501 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
503 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
504 * | Cookie (optional, maximum 64 bits)...
505 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
507 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
509 * L2TPv3 L2-Specific Sublayer Format
512 * 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
513 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
514 * |x|S|x|x|x|x|x|x| Sequence Number |
515 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
517 * Cookie value, sublayer format and offset (pad) are negotiated with
518 * the peer when the session is set up. Unlike L2TPv2, we do not need
519 * to parse the packet header to determine if optional fields are
522 * Caller must already have parsed the frame and determined that it is
523 * a data (not control) frame before coming here. Fields up to the
524 * session-id have already been parsed and ptr points to the data
525 * after the session-id.
527 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
528 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
529 int length, int (*payload_hook)(struct sk_buff *skb))
531 struct l2tp_tunnel *tunnel = session->tunnel;
535 /* The ref count is increased since we now hold a pointer to
536 * the session. Take care to decrement the refcnt when exiting
537 * this function from now on...
539 l2tp_session_inc_refcount(session);
541 (*session->ref)(session);
543 /* Parse and check optional cookie */
544 if (session->peer_cookie_len > 0) {
545 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
546 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
547 "%s: cookie mismatch (%u/%u). Discarding.\n",
548 tunnel->name, tunnel->tunnel_id, session->session_id);
549 session->stats.rx_cookie_discards++;
552 ptr += session->peer_cookie_len;
555 /* Handle the optional sequence numbers. Sequence numbers are
556 * in different places for L2TPv2 and L2TPv3.
558 * If we are the LAC, enable/disable sequence numbers under
559 * the control of the LNS. If no sequence numbers present but
560 * we were expecting them, discard frame.
563 L2TP_SKB_CB(skb)->has_seq = 0;
564 if (tunnel->version == L2TP_HDR_VER_2) {
565 if (hdrflags & L2TP_HDRFLAG_S) {
566 ns = ntohs(*(__be16 *) ptr);
568 nr = ntohs(*(__be16 *) ptr);
571 /* Store L2TP info in the skb */
572 L2TP_SKB_CB(skb)->ns = ns;
573 L2TP_SKB_CB(skb)->has_seq = 1;
575 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
576 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
577 session->name, ns, nr, session->nr);
579 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
580 u32 l2h = ntohl(*(__be32 *) ptr);
582 if (l2h & 0x40000000) {
583 ns = l2h & 0x00ffffff;
585 /* Store L2TP info in the skb */
586 L2TP_SKB_CB(skb)->ns = ns;
587 L2TP_SKB_CB(skb)->has_seq = 1;
589 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
590 "%s: recv data ns=%u, session nr=%u\n",
591 session->name, ns, session->nr);
595 /* Advance past L2-specific header, if present */
596 ptr += session->l2specific_len;
598 if (L2TP_SKB_CB(skb)->has_seq) {
599 /* Received a packet with sequence numbers. If we're the LNS,
600 * check if we sre sending sequence numbers and if not,
603 if ((!session->lns_mode) && (!session->send_seq)) {
604 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
605 "%s: requested to enable seq numbers by LNS\n",
607 session->send_seq = -1;
608 l2tp_session_set_header_len(session, tunnel->version);
611 /* No sequence numbers.
612 * If user has configured mandatory sequence numbers, discard.
614 if (session->recv_seq) {
615 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
616 "%s: recv data has no seq numbers when required. "
617 "Discarding\n", session->name);
618 session->stats.rx_seq_discards++;
622 /* If we're the LAC and we're sending sequence numbers, the
623 * LNS has requested that we no longer send sequence numbers.
624 * If we're the LNS and we're sending sequence numbers, the
625 * LAC is broken. Discard the frame.
627 if ((!session->lns_mode) && (session->send_seq)) {
628 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
629 "%s: requested to disable seq numbers by LNS\n",
631 session->send_seq = 0;
632 l2tp_session_set_header_len(session, tunnel->version);
633 } else if (session->send_seq) {
634 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
635 "%s: recv data has no seq numbers when required. "
636 "Discarding\n", session->name);
637 session->stats.rx_seq_discards++;
642 /* Session data offset is handled differently for L2TPv2 and
643 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
644 * the header. For L2TPv3, the offset is negotiated using AVPs
645 * in the session setup control protocol.
647 if (tunnel->version == L2TP_HDR_VER_2) {
648 /* If offset bit set, skip it. */
649 if (hdrflags & L2TP_HDRFLAG_O) {
650 offset = ntohs(*(__be16 *)ptr);
654 ptr += session->offset;
657 if (!pskb_may_pull(skb, offset))
660 __skb_pull(skb, offset);
662 /* If caller wants to process the payload before we queue the
666 if ((*payload_hook)(skb))
669 /* Prepare skb for adding to the session's reorder_q. Hold
670 * packets for max reorder_timeout or 1 second if not
673 L2TP_SKB_CB(skb)->length = length;
674 L2TP_SKB_CB(skb)->expires = jiffies +
675 (session->reorder_timeout ? session->reorder_timeout : HZ);
677 /* Add packet to the session's receive queue. Reordering is done here, if
678 * enabled. Saved L2TP protocol info is stored in skb->sb[].
680 if (L2TP_SKB_CB(skb)->has_seq) {
681 if (session->reorder_timeout != 0) {
682 /* Packet reordering enabled. Add skb to session's
683 * reorder queue, in order of ns.
685 l2tp_recv_queue_skb(session, skb);
687 /* Packet reordering disabled. Discard out-of-sequence
690 if (L2TP_SKB_CB(skb)->ns != session->nr) {
691 session->stats.rx_seq_discards++;
692 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
693 "%s: oos pkt %u len %d discarded, "
694 "waiting for %u, reorder_q_len=%d\n",
695 session->name, L2TP_SKB_CB(skb)->ns,
696 L2TP_SKB_CB(skb)->length, session->nr,
697 skb_queue_len(&session->reorder_q));
700 skb_queue_tail(&session->reorder_q, skb);
703 /* No sequence numbers. Add the skb to the tail of the
704 * reorder queue. This ensures that it will be
705 * delivered after all previous sequenced skbs.
707 skb_queue_tail(&session->reorder_q, skb);
710 /* Try to dequeue as many skbs from reorder_q as we can. */
711 l2tp_recv_dequeue(session);
713 l2tp_session_dec_refcount(session);
718 session->stats.rx_errors++;
722 (*session->deref)(session);
724 l2tp_session_dec_refcount(session);
726 EXPORT_SYMBOL(l2tp_recv_common);
728 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
729 * here. The skb is not on a list when we get here.
730 * Returns 0 if the packet was a data packet and was successfully passed on.
731 * Returns 1 if the packet was not a good data packet and could not be
732 * forwarded. All such packets are passed up to userspace to deal with.
734 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
735 int (*payload_hook)(struct sk_buff *skb))
737 struct l2tp_session *session = NULL;
738 unsigned char *ptr, *optr;
740 u32 tunnel_id, session_id;
745 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
746 goto discard_bad_csum;
748 /* UDP always verifies the packet length. */
749 __skb_pull(skb, sizeof(struct udphdr));
752 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
753 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
754 "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
758 /* Point to L2TP header */
759 optr = ptr = skb->data;
761 /* Trace packet contents, if enabled */
762 if (tunnel->debug & L2TP_MSG_DATA) {
763 length = min(32u, skb->len);
764 if (!pskb_may_pull(skb, length))
767 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
771 printk(" %02X", ptr[offset]);
772 } while (++offset < length);
777 /* Get L2TP header flags */
778 hdrflags = ntohs(*(__be16 *) ptr);
780 /* Check protocol version */
781 version = hdrflags & L2TP_HDR_VER_MASK;
782 if (version != tunnel->version) {
783 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
784 "%s: recv protocol version mismatch: got %d expected %d\n",
785 tunnel->name, version, tunnel->version);
789 /* Get length of L2TP packet */
792 /* If type is control packet, it is handled by userspace. */
793 if (hdrflags & L2TP_HDRFLAG_T) {
794 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
795 "%s: recv control packet, len=%d\n", tunnel->name, length);
802 if (tunnel->version == L2TP_HDR_VER_2) {
803 /* If length is present, skip it */
804 if (hdrflags & L2TP_HDRFLAG_L)
807 /* Extract tunnel and session ID */
808 tunnel_id = ntohs(*(__be16 *) ptr);
810 session_id = ntohs(*(__be16 *) ptr);
813 ptr += 2; /* skip reserved bits */
814 tunnel_id = tunnel->tunnel_id;
815 session_id = ntohl(*(__be32 *) ptr);
819 /* Find the session context */
820 session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id);
821 if (!session || !session->recv_skb) {
822 /* Not found? Pass to userspace to deal with */
823 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
824 "%s: no session found (%u/%u). Passing up.\n",
825 tunnel->name, tunnel_id, session_id);
829 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
834 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
835 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
836 tunnel->stats.rx_errors++;
842 /* Put UDP header back */
843 __skb_push(skb, sizeof(struct udphdr));
848 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
852 * >0: skb should be passed up to userspace as UDP.
854 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
856 struct l2tp_tunnel *tunnel;
858 tunnel = l2tp_sock_to_tunnel(sk);
862 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
863 "%s: received %d bytes\n", tunnel->name, skb->len);
865 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
876 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
878 /************************************************************************
880 ***********************************************************************/
882 /* Build an L2TP header for the session into the buffer provided.
884 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
886 struct l2tp_tunnel *tunnel = session->tunnel;
889 u16 flags = L2TP_HDR_VER_2;
890 u32 tunnel_id = tunnel->peer_tunnel_id;
891 u32 session_id = session->peer_session_id;
893 if (session->send_seq)
894 flags |= L2TP_HDRFLAG_S;
896 /* Setup L2TP header. */
897 *bufp++ = htons(flags);
898 *bufp++ = htons(tunnel_id);
899 *bufp++ = htons(session_id);
900 if (session->send_seq) {
901 *bufp++ = htons(session->ns);
904 session->ns &= 0xffff;
905 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
906 "%s: updated ns to %u\n", session->name, session->ns);
912 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
914 struct l2tp_tunnel *tunnel = session->tunnel;
918 /* Setup L2TP header. The header differs slightly for UDP and
919 * IP encapsulations. For UDP, there is 4 bytes of flags.
921 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
922 u16 flags = L2TP_HDR_VER_3;
923 *((__be16 *) bufp) = htons(flags);
925 *((__be16 *) bufp) = 0;
929 *((__be32 *) bufp) = htonl(session->peer_session_id);
931 if (session->cookie_len) {
932 memcpy(bufp, &session->cookie[0], session->cookie_len);
933 bufp += session->cookie_len;
935 if (session->l2specific_len) {
936 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
938 if (session->send_seq) {
939 l2h = 0x40000000 | session->ns;
941 session->ns &= 0xffffff;
942 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
943 "%s: updated ns to %u\n", session->name, session->ns);
946 *((__be32 *) bufp) = htonl(l2h);
948 bufp += session->l2specific_len;
951 bufp += session->offset;
956 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
957 struct flowi *fl, size_t data_len)
959 struct l2tp_tunnel *tunnel = session->tunnel;
960 unsigned int len = skb->len;
964 if (session->send_seq)
965 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
966 "%s: send %Zd bytes, ns=%u\n", session->name,
967 data_len, session->ns - 1);
969 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
970 "%s: send %Zd bytes\n", session->name, data_len);
972 if (session->debug & L2TP_MSG_DATA) {
974 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
975 unsigned char *datap = skb->data + uhlen;
977 printk(KERN_DEBUG "%s: xmit:", session->name);
978 for (i = 0; i < (len - uhlen); i++) {
979 printk(" %02X", *datap++);
988 /* Queue the packet to IP for output */
990 error = ip_queue_xmit(skb, fl);
994 tunnel->stats.tx_packets++;
995 tunnel->stats.tx_bytes += len;
996 session->stats.tx_packets++;
997 session->stats.tx_bytes += len;
999 tunnel->stats.tx_errors++;
1000 session->stats.tx_errors++;
1006 /* Automatically called when the skb is freed.
1008 static void l2tp_sock_wfree(struct sk_buff *skb)
1013 /* For data skbs that we transmit, we associate with the tunnel socket
1014 * but don't do accounting.
1016 static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1020 skb->destructor = l2tp_sock_wfree;
1023 /* If caller requires the skb to have a ppp header, the header must be
1024 * inserted in the skb data before calling this function.
1026 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1028 int data_len = skb->len;
1029 struct l2tp_tunnel *tunnel = session->tunnel;
1030 struct sock *sk = tunnel->sock;
1033 struct inet_sock *inet;
1038 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1041 /* Check that there's enough headroom in the skb to insert IP,
1042 * UDP and L2TP headers. If not enough, expand it to
1043 * make room. Adjust truesize.
1045 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1047 old_headroom = skb_headroom(skb);
1048 if (skb_cow_head(skb, headroom))
1051 new_headroom = skb_headroom(skb);
1053 skb->truesize += new_headroom - old_headroom;
1055 /* Setup L2TP header */
1056 session->build_header(session, __skb_push(skb, hdr_len));
1058 /* Reset skb netfilter state */
1059 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1060 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1065 if (sock_owned_by_user(sk)) {
1070 /* Get routing info from the tunnel socket */
1072 skb_dst_set(skb, dst_clone(__sk_dst_get(sk)));
1075 fl = &inet->cork.fl;
1076 switch (tunnel->encap) {
1077 case L2TP_ENCAPTYPE_UDP:
1078 /* Setup UDP header */
1079 __skb_push(skb, sizeof(*uh));
1080 skb_reset_transport_header(skb);
1082 uh->source = inet->inet_sport;
1083 uh->dest = inet->inet_dport;
1084 udp_len = uhlen + hdr_len + data_len;
1085 uh->len = htons(udp_len);
1088 /* Calculate UDP checksum if configured to do so */
1089 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1090 skb->ip_summed = CHECKSUM_NONE;
1091 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1092 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1093 skb->ip_summed = CHECKSUM_COMPLETE;
1094 csum = skb_checksum(skb, 0, udp_len, 0);
1095 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1097 udp_len, IPPROTO_UDP, csum);
1099 uh->check = CSUM_MANGLED_0;
1101 skb->ip_summed = CHECKSUM_PARTIAL;
1102 skb->csum_start = skb_transport_header(skb) - skb->head;
1103 skb->csum_offset = offsetof(struct udphdr, check);
1104 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1106 udp_len, IPPROTO_UDP, 0);
1110 case L2TP_ENCAPTYPE_IP:
1114 l2tp_skb_set_owner_w(skb, sk);
1116 l2tp_xmit_core(session, skb, fl, data_len);
1123 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1125 /*****************************************************************************
1126 * Tinnel and session create/destroy.
1127 *****************************************************************************/
1129 /* Tunnel socket destruct hook.
1130 * The tunnel context is deleted only when all session sockets have been
1133 static void l2tp_tunnel_destruct(struct sock *sk)
1135 struct l2tp_tunnel *tunnel;
1137 tunnel = sk->sk_user_data;
1141 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1142 "%s: closing...\n", tunnel->name);
1144 /* Close all sessions */
1145 l2tp_tunnel_closeall(tunnel);
1147 switch (tunnel->encap) {
1148 case L2TP_ENCAPTYPE_UDP:
1149 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1150 (udp_sk(sk))->encap_type = 0;
1151 (udp_sk(sk))->encap_rcv = NULL;
1153 case L2TP_ENCAPTYPE_IP:
1157 /* Remove hooks into tunnel socket */
1158 tunnel->sock = NULL;
1159 sk->sk_destruct = tunnel->old_sk_destruct;
1160 sk->sk_user_data = NULL;
1162 /* Call the original destructor */
1163 if (sk->sk_destruct)
1164 (*sk->sk_destruct)(sk);
1166 /* We're finished with the socket */
1167 l2tp_tunnel_dec_refcount(tunnel);
1173 /* When the tunnel is closed, all the attached sessions need to go too.
1175 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1178 struct hlist_node *walk;
1179 struct hlist_node *tmp;
1180 struct l2tp_session *session;
1182 BUG_ON(tunnel == NULL);
1184 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1185 "%s: closing all sessions...\n", tunnel->name);
1187 write_lock_bh(&tunnel->hlist_lock);
1188 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1190 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1191 session = hlist_entry(walk, struct l2tp_session, hlist);
1193 PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO,
1194 "%s: closing session\n", session->name);
1196 hlist_del_init(&session->hlist);
1198 /* Since we should hold the sock lock while
1199 * doing any unbinding, we need to release the
1200 * lock we're holding before taking that lock.
1201 * Hold a reference to the sock so it doesn't
1202 * disappear as we're jumping between locks.
1204 if (session->ref != NULL)
1205 (*session->ref)(session);
1207 write_unlock_bh(&tunnel->hlist_lock);
1209 if (tunnel->version != L2TP_HDR_VER_2) {
1210 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1212 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1213 hlist_del_init_rcu(&session->global_hlist);
1214 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1218 if (session->session_close != NULL)
1219 (*session->session_close)(session);
1221 if (session->deref != NULL)
1222 (*session->deref)(session);
1224 write_lock_bh(&tunnel->hlist_lock);
1226 /* Now restart from the beginning of this hash
1227 * chain. We always remove a session from the
1228 * list so we are guaranteed to make forward
1234 write_unlock_bh(&tunnel->hlist_lock);
1237 /* Really kill the tunnel.
1238 * Come here only when all sessions have been cleared from the tunnel.
1240 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
1242 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1244 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1245 BUG_ON(tunnel->sock != NULL);
1247 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1248 "%s: free...\n", tunnel->name);
1250 /* Remove from tunnel list */
1251 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1252 list_del_rcu(&tunnel->list);
1253 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1256 atomic_dec(&l2tp_tunnel_count);
1260 /* Create a socket for the tunnel, if one isn't set up by
1261 * userspace. This is used for static tunnels where there is no
1262 * managing L2TP daemon.
1264 static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1267 struct sockaddr_in udp_addr;
1268 struct sockaddr_l2tpip ip_addr;
1269 struct socket *sock = NULL;
1271 switch (cfg->encap) {
1272 case L2TP_ENCAPTYPE_UDP:
1273 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1279 memset(&udp_addr, 0, sizeof(udp_addr));
1280 udp_addr.sin_family = AF_INET;
1281 udp_addr.sin_addr = cfg->local_ip;
1282 udp_addr.sin_port = htons(cfg->local_udp_port);
1283 err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr));
1287 udp_addr.sin_family = AF_INET;
1288 udp_addr.sin_addr = cfg->peer_ip;
1289 udp_addr.sin_port = htons(cfg->peer_udp_port);
1290 err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0);
1294 if (!cfg->use_udp_checksums)
1295 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1299 case L2TP_ENCAPTYPE_IP:
1300 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
1306 memset(&ip_addr, 0, sizeof(ip_addr));
1307 ip_addr.l2tp_family = AF_INET;
1308 ip_addr.l2tp_addr = cfg->local_ip;
1309 ip_addr.l2tp_conn_id = tunnel_id;
1310 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr));
1314 ip_addr.l2tp_family = AF_INET;
1315 ip_addr.l2tp_addr = cfg->peer_ip;
1316 ip_addr.l2tp_conn_id = peer_tunnel_id;
1317 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0);
1328 if ((err < 0) && sock) {
1336 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)
1338 struct l2tp_tunnel *tunnel = NULL;
1340 struct socket *sock = NULL;
1341 struct sock *sk = NULL;
1342 struct l2tp_net *pn;
1343 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1345 /* Get the tunnel socket from the fd, which was opened by
1346 * the userspace L2TP daemon. If not specified, create a
1350 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1355 sock = sockfd_lookup(fd, &err);
1357 printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1358 tunnel_id, fd, err);
1368 /* Quick sanity checks */
1370 case L2TP_ENCAPTYPE_UDP:
1371 err = -EPROTONOSUPPORT;
1372 if (sk->sk_protocol != IPPROTO_UDP) {
1373 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1374 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1378 case L2TP_ENCAPTYPE_IP:
1379 err = -EPROTONOSUPPORT;
1380 if (sk->sk_protocol != IPPROTO_L2TP) {
1381 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1382 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1388 /* Check if this socket has already been prepped */
1389 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1390 if (tunnel != NULL) {
1391 /* This socket has already been prepped */
1396 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1397 if (tunnel == NULL) {
1402 tunnel->version = version;
1403 tunnel->tunnel_id = tunnel_id;
1404 tunnel->peer_tunnel_id = peer_tunnel_id;
1405 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1407 tunnel->magic = L2TP_TUNNEL_MAGIC;
1408 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1409 rwlock_init(&tunnel->hlist_lock);
1411 /* The net we belong to */
1412 tunnel->l2tp_net = net;
1413 pn = l2tp_pernet(net);
1416 tunnel->debug = cfg->debug;
1418 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1419 tunnel->encap = encap;
1420 if (encap == L2TP_ENCAPTYPE_UDP) {
1421 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1422 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1423 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1426 sk->sk_user_data = tunnel;
1428 /* Hook on the tunnel socket destructor so that we can cleanup
1429 * if the tunnel socket goes away.
1431 tunnel->old_sk_destruct = sk->sk_destruct;
1432 sk->sk_destruct = &l2tp_tunnel_destruct;
1434 sk->sk_allocation = GFP_ATOMIC;
1436 /* Add tunnel to our list */
1437 INIT_LIST_HEAD(&tunnel->list);
1438 atomic_inc(&l2tp_tunnel_count);
1440 /* Bump the reference count. The tunnel context is deleted
1441 * only when this drops to zero. Must be done before list insertion
1443 l2tp_tunnel_inc_refcount(tunnel);
1444 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1445 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1446 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1453 /* If tunnel's socket was created by the kernel, it doesn't
1456 if (sock && sock->file)
1461 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1463 /* This function is used by the netlink TUNNEL_DELETE command.
1465 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1468 struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL;
1470 /* Force the tunnel socket to close. This will eventually
1471 * cause the tunnel to be deleted via the normal socket close
1472 * mechanisms when userspace closes the tunnel socket.
1475 err = inet_shutdown(sock, 2);
1477 /* If the tunnel's socket was created by the kernel,
1478 * close the socket here since the socket was not
1479 * created by userspace.
1481 if (sock->file == NULL)
1482 err = inet_release(sock);
1487 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1489 /* Really kill the session.
1491 void l2tp_session_free(struct l2tp_session *session)
1493 struct l2tp_tunnel *tunnel;
1495 BUG_ON(atomic_read(&session->ref_count) != 0);
1497 tunnel = session->tunnel;
1498 if (tunnel != NULL) {
1499 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1501 /* Delete the session from the hash */
1502 write_lock_bh(&tunnel->hlist_lock);
1503 hlist_del_init(&session->hlist);
1504 write_unlock_bh(&tunnel->hlist_lock);
1506 /* Unlink from the global hash if not L2TPv2 */
1507 if (tunnel->version != L2TP_HDR_VER_2) {
1508 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1510 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1511 hlist_del_init_rcu(&session->global_hlist);
1512 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1516 if (session->session_id != 0)
1517 atomic_dec(&l2tp_session_count);
1519 sock_put(tunnel->sock);
1521 /* This will delete the tunnel context if this
1522 * is the last session on the tunnel.
1524 session->tunnel = NULL;
1525 l2tp_tunnel_dec_refcount(tunnel);
1532 EXPORT_SYMBOL_GPL(l2tp_session_free);
1534 /* This function is used by the netlink SESSION_DELETE command and by
1537 int l2tp_session_delete(struct l2tp_session *session)
1539 if (session->session_close != NULL)
1540 (*session->session_close)(session);
1542 l2tp_session_dec_refcount(session);
1546 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1549 /* We come here whenever a session's send_seq, cookie_len or
1550 * l2specific_len parameters are set.
1552 static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1554 if (version == L2TP_HDR_VER_2) {
1555 session->hdr_len = 6;
1556 if (session->send_seq)
1557 session->hdr_len += 4;
1559 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1560 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1561 session->hdr_len += 4;
1566 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)
1568 struct l2tp_session *session;
1570 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1571 if (session != NULL) {
1572 session->magic = L2TP_SESSION_MAGIC;
1573 session->tunnel = tunnel;
1575 session->session_id = session_id;
1576 session->peer_session_id = peer_session_id;
1579 sprintf(&session->name[0], "sess %u/%u",
1580 tunnel->tunnel_id, session->session_id);
1582 skb_queue_head_init(&session->reorder_q);
1584 INIT_HLIST_NODE(&session->hlist);
1585 INIT_HLIST_NODE(&session->global_hlist);
1587 /* Inherit debug options from tunnel */
1588 session->debug = tunnel->debug;
1591 session->pwtype = cfg->pw_type;
1592 session->debug = cfg->debug;
1593 session->mtu = cfg->mtu;
1594 session->mru = cfg->mru;
1595 session->send_seq = cfg->send_seq;
1596 session->recv_seq = cfg->recv_seq;
1597 session->lns_mode = cfg->lns_mode;
1598 session->reorder_timeout = cfg->reorder_timeout;
1599 session->offset = cfg->offset;
1600 session->l2specific_type = cfg->l2specific_type;
1601 session->l2specific_len = cfg->l2specific_len;
1602 session->cookie_len = cfg->cookie_len;
1603 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1604 session->peer_cookie_len = cfg->peer_cookie_len;
1605 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1608 if (tunnel->version == L2TP_HDR_VER_2)
1609 session->build_header = l2tp_build_l2tpv2_header;
1611 session->build_header = l2tp_build_l2tpv3_header;
1613 l2tp_session_set_header_len(session, tunnel->version);
1615 /* Bump the reference count. The session context is deleted
1616 * only when this drops to zero.
1618 l2tp_session_inc_refcount(session);
1619 l2tp_tunnel_inc_refcount(tunnel);
1621 /* Ensure tunnel socket isn't deleted */
1622 sock_hold(tunnel->sock);
1624 /* Add session to the tunnel's hash list */
1625 write_lock_bh(&tunnel->hlist_lock);
1626 hlist_add_head(&session->hlist,
1627 l2tp_session_id_hash(tunnel, session_id));
1628 write_unlock_bh(&tunnel->hlist_lock);
1630 /* And to the global session list if L2TPv3 */
1631 if (tunnel->version != L2TP_HDR_VER_2) {
1632 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1634 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1635 hlist_add_head_rcu(&session->global_hlist,
1636 l2tp_session_id_hash_2(pn, session_id));
1637 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1640 /* Ignore management session in session count value */
1641 if (session->session_id != 0)
1642 atomic_inc(&l2tp_session_count);
1647 EXPORT_SYMBOL_GPL(l2tp_session_create);
1649 /*****************************************************************************
1651 *****************************************************************************/
1653 static __net_init int l2tp_init_net(struct net *net)
1655 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1658 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1659 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1661 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1662 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1664 spin_lock_init(&pn->l2tp_session_hlist_lock);
1669 static struct pernet_operations l2tp_net_ops = {
1670 .init = l2tp_init_net,
1672 .size = sizeof(struct l2tp_net),
1675 static int __init l2tp_init(void)
1679 rc = register_pernet_device(&l2tp_net_ops);
1683 printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION);
1689 static void __exit l2tp_exit(void)
1691 unregister_pernet_device(&l2tp_net_ops);
1694 module_init(l2tp_init);
1695 module_exit(l2tp_exit);
1697 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1698 MODULE_DESCRIPTION("L2TP core");
1699 MODULE_LICENSE("GPL");
1700 MODULE_VERSION(L2TP_DRV_VERSION);