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_closeall(struct l2tp_tunnel *tunnel);
117 static inline struct l2tp_net *l2tp_pernet(const struct net *net)
121 return net_generic(net, l2tp_net_id);
125 /* Session hash global list for L2TPv3.
126 * The session_id SHOULD be random according to RFC3931, but several
127 * L2TP implementations use incrementing session_ids. So we do a real
128 * hash on the session_id, rather than a simple bitmask.
130 static inline struct hlist_head *
131 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
133 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
137 /* Lookup a session by id in the global session list
139 static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
141 struct l2tp_net *pn = l2tp_pernet(net);
142 struct hlist_head *session_list =
143 l2tp_session_id_hash_2(pn, session_id);
144 struct l2tp_session *session;
145 struct hlist_node *walk;
148 hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
149 if (session->session_id == session_id) {
150 rcu_read_unlock_bh();
154 rcu_read_unlock_bh();
159 /* Session hash list.
160 * The session_id SHOULD be random according to RFC2661, but several
161 * L2TP implementations (Cisco and Microsoft) use incrementing
162 * session_ids. So we do a real hash on the session_id, rather than a
165 static inline struct hlist_head *
166 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
168 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
171 /* Lookup a session by id
173 struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
175 struct hlist_head *session_list;
176 struct l2tp_session *session;
177 struct hlist_node *walk;
179 /* In L2TPv3, session_ids are unique over all tunnels and we
180 * sometimes need to look them up before we know the
184 return l2tp_session_find_2(net, session_id);
186 session_list = l2tp_session_id_hash(tunnel, session_id);
187 read_lock_bh(&tunnel->hlist_lock);
188 hlist_for_each_entry(session, walk, session_list, hlist) {
189 if (session->session_id == session_id) {
190 read_unlock_bh(&tunnel->hlist_lock);
194 read_unlock_bh(&tunnel->hlist_lock);
198 EXPORT_SYMBOL_GPL(l2tp_session_find);
200 /* Lookup a tunnel. A new reference is held on the returned tunnel. */
201 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id)
203 const struct l2tp_net *pn = l2tp_pernet(net);
204 struct l2tp_tunnel *tunnel;
207 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
208 if (tunnel->tunnel_id == tunnel_id) {
209 l2tp_tunnel_inc_refcount(tunnel);
210 rcu_read_unlock_bh();
215 rcu_read_unlock_bh();
219 EXPORT_SYMBOL_GPL(l2tp_tunnel_get);
221 /* Like l2tp_session_find() but takes a reference on the returned session.
222 * Optionally calls session->ref() too if do_ref is true.
224 struct l2tp_session *l2tp_session_get(const struct net *net,
225 struct l2tp_tunnel *tunnel,
226 u32 session_id, bool do_ref)
228 struct hlist_head *session_list;
229 struct l2tp_session *session;
230 struct hlist_node *walk;
233 struct l2tp_net *pn = l2tp_pernet(net);
235 session_list = l2tp_session_id_hash_2(pn, session_id);
238 hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
239 if (session->session_id == session_id) {
240 l2tp_session_inc_refcount(session);
241 if (do_ref && session->ref)
242 session->ref(session);
243 rcu_read_unlock_bh();
248 rcu_read_unlock_bh();
253 session_list = l2tp_session_id_hash(tunnel, session_id);
254 read_lock_bh(&tunnel->hlist_lock);
255 hlist_for_each_entry(session, walk, session_list, hlist) {
256 if (session->session_id == session_id) {
257 l2tp_session_inc_refcount(session);
258 if (do_ref && session->ref)
259 session->ref(session);
260 read_unlock_bh(&tunnel->hlist_lock);
265 read_unlock_bh(&tunnel->hlist_lock);
269 EXPORT_SYMBOL_GPL(l2tp_session_get);
271 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
275 struct hlist_node *walk;
276 struct l2tp_session *session;
279 read_lock_bh(&tunnel->hlist_lock);
280 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
281 hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) {
283 l2tp_session_inc_refcount(session);
284 if (do_ref && session->ref)
285 session->ref(session);
286 read_unlock_bh(&tunnel->hlist_lock);
292 read_unlock_bh(&tunnel->hlist_lock);
296 EXPORT_SYMBOL_GPL(l2tp_session_get_nth);
298 /* Lookup a session by interface name.
299 * This is very inefficient but is only used by management interfaces.
301 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
305 struct l2tp_net *pn = l2tp_pernet(net);
307 struct hlist_node *walk;
308 struct l2tp_session *session;
311 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
312 hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
313 if (!strcmp(session->ifname, ifname)) {
314 l2tp_session_inc_refcount(session);
315 if (do_ref && session->ref)
316 session->ref(session);
317 rcu_read_unlock_bh();
324 rcu_read_unlock_bh();
328 EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname);
330 int l2tp_session_register(struct l2tp_session *session,
331 struct l2tp_tunnel *tunnel)
333 struct l2tp_session *session_walk;
334 struct hlist_head *g_head;
335 struct hlist_head *head;
337 struct hlist_node *walk;
340 head = l2tp_session_id_hash(tunnel, session->session_id);
342 write_lock_bh(&tunnel->hlist_lock);
343 if (!tunnel->acpt_newsess) {
348 hlist_for_each_entry(session_walk, walk, head, hlist)
349 if (session_walk->session_id == session->session_id) {
354 if (tunnel->version == L2TP_HDR_VER_3) {
355 pn = l2tp_pernet(tunnel->l2tp_net);
356 g_head = l2tp_session_id_hash_2(l2tp_pernet(tunnel->l2tp_net),
357 session->session_id);
359 spin_lock_bh(&pn->l2tp_session_hlist_lock);
361 hlist_for_each_entry(session_walk, walk, g_head, global_hlist)
362 if (session_walk->session_id == session->session_id) {
364 goto err_tlock_pnlock;
367 l2tp_tunnel_inc_refcount(tunnel);
368 sock_hold(tunnel->sock);
369 hlist_add_head_rcu(&session->global_hlist, g_head);
371 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
373 l2tp_tunnel_inc_refcount(tunnel);
374 sock_hold(tunnel->sock);
377 hlist_add_head(&session->hlist, head);
378 write_unlock_bh(&tunnel->hlist_lock);
380 /* Ignore management session in session count value */
381 if (session->session_id != 0)
382 atomic_inc(&l2tp_session_count);
387 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
389 write_unlock_bh(&tunnel->hlist_lock);
393 EXPORT_SYMBOL_GPL(l2tp_session_register);
395 /* Lookup a tunnel by id
397 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
399 struct l2tp_tunnel *tunnel;
400 struct l2tp_net *pn = l2tp_pernet(net);
403 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
404 if (tunnel->tunnel_id == tunnel_id) {
405 rcu_read_unlock_bh();
409 rcu_read_unlock_bh();
413 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
415 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
417 struct l2tp_net *pn = l2tp_pernet(net);
418 struct l2tp_tunnel *tunnel;
422 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
424 rcu_read_unlock_bh();
429 rcu_read_unlock_bh();
433 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
435 /*****************************************************************************
436 * Receive data handling
437 *****************************************************************************/
439 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
442 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
444 struct sk_buff *skbp;
446 u32 ns = L2TP_SKB_CB(skb)->ns;
448 spin_lock_bh(&session->reorder_q.lock);
449 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
450 if (L2TP_SKB_CB(skbp)->ns > ns) {
451 __skb_queue_before(&session->reorder_q, skbp, skb);
452 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
453 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
454 session->name, ns, L2TP_SKB_CB(skbp)->ns,
455 skb_queue_len(&session->reorder_q));
456 session->stats.rx_oos_packets++;
461 __skb_queue_tail(&session->reorder_q, skb);
464 spin_unlock_bh(&session->reorder_q.lock);
467 /* Dequeue a single skb.
469 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
471 struct l2tp_tunnel *tunnel = session->tunnel;
472 int length = L2TP_SKB_CB(skb)->length;
474 /* We're about to requeue the skb, so return resources
475 * to its current owner (a socket receive buffer).
479 tunnel->stats.rx_packets++;
480 tunnel->stats.rx_bytes += length;
481 session->stats.rx_packets++;
482 session->stats.rx_bytes += length;
484 if (L2TP_SKB_CB(skb)->has_seq) {
487 if (tunnel->version == L2TP_HDR_VER_2)
488 session->nr &= 0xffff;
490 session->nr &= 0xffffff;
492 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
493 "%s: updated nr to %hu\n", session->name, session->nr);
496 /* call private receive handler */
497 if (session->recv_skb != NULL)
498 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
503 (*session->deref)(session);
506 /* Dequeue skbs from the session's reorder_q, subject to packet order.
507 * Skbs that have been in the queue for too long are simply discarded.
509 static void l2tp_recv_dequeue(struct l2tp_session *session)
514 /* If the pkt at the head of the queue has the nr that we
515 * expect to send up next, dequeue it and any other
516 * in-sequence packets behind it.
519 spin_lock_bh(&session->reorder_q.lock);
520 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
521 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
522 session->stats.rx_seq_discards++;
523 session->stats.rx_errors++;
524 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
525 "%s: oos pkt %u len %d discarded (too old), "
526 "waiting for %u, reorder_q_len=%d\n",
527 session->name, L2TP_SKB_CB(skb)->ns,
528 L2TP_SKB_CB(skb)->length, session->nr,
529 skb_queue_len(&session->reorder_q));
530 __skb_unlink(skb, &session->reorder_q);
533 (*session->deref)(session);
537 if (L2TP_SKB_CB(skb)->has_seq) {
538 if (L2TP_SKB_CB(skb)->ns != session->nr) {
539 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
540 "%s: holding oos pkt %u len %d, "
541 "waiting for %u, reorder_q_len=%d\n",
542 session->name, L2TP_SKB_CB(skb)->ns,
543 L2TP_SKB_CB(skb)->length, session->nr,
544 skb_queue_len(&session->reorder_q));
548 __skb_unlink(skb, &session->reorder_q);
550 /* Process the skb. We release the queue lock while we
551 * do so to let other contexts process the queue.
553 spin_unlock_bh(&session->reorder_q.lock);
554 l2tp_recv_dequeue_skb(session, skb);
559 spin_unlock_bh(&session->reorder_q.lock);
562 static inline int l2tp_verify_udp_checksum(struct sock *sk,
565 struct udphdr *uh = udp_hdr(skb);
566 u16 ulen = ntohs(uh->len);
567 struct inet_sock *inet;
570 if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
574 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
577 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
578 !csum_fold(csum_add(psum, skb->csum)))
583 return __skb_checksum_complete(skb);
586 /* Do receive processing of L2TP data frames. We handle both L2TPv2
587 * and L2TPv3 data frames here.
589 * L2TPv2 Data Message Header
592 * 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
593 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
594 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
595 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
596 * | Tunnel ID | Session ID |
597 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
598 * | Ns (opt) | Nr (opt) |
599 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
600 * | Offset Size (opt) | Offset pad... (opt)
601 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
603 * Data frames are marked by T=0. All other fields are the same as
604 * those in L2TP control frames.
606 * L2TPv3 Data Message Header
608 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
609 * | L2TP Session Header |
610 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
611 * | L2-Specific Sublayer |
612 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
613 * | Tunnel Payload ...
614 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
616 * L2TPv3 Session Header Over IP
619 * 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
620 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
622 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
623 * | Cookie (optional, maximum 64 bits)...
624 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
626 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
628 * L2TPv3 L2-Specific Sublayer Format
631 * 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
632 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
633 * |x|S|x|x|x|x|x|x| Sequence Number |
634 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
636 * Cookie value, sublayer format and offset (pad) are negotiated with
637 * the peer when the session is set up. Unlike L2TPv2, we do not need
638 * to parse the packet header to determine if optional fields are
641 * Caller must already have parsed the frame and determined that it is
642 * a data (not control) frame before coming here. Fields up to the
643 * session-id have already been parsed and ptr points to the data
644 * after the session-id.
646 * session->ref() must have been called prior to l2tp_recv_common().
647 * session->deref() will be called automatically after skb is processed.
649 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
650 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
651 int length, int (*payload_hook)(struct sk_buff *skb))
653 struct l2tp_tunnel *tunnel = session->tunnel;
657 /* Parse and check optional cookie */
658 if (session->peer_cookie_len > 0) {
659 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
660 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
661 "%s: cookie mismatch (%u/%u). Discarding.\n",
662 tunnel->name, tunnel->tunnel_id, session->session_id);
663 session->stats.rx_cookie_discards++;
666 ptr += session->peer_cookie_len;
669 /* Handle the optional sequence numbers. Sequence numbers are
670 * in different places for L2TPv2 and L2TPv3.
672 * If we are the LAC, enable/disable sequence numbers under
673 * the control of the LNS. If no sequence numbers present but
674 * we were expecting them, discard frame.
677 L2TP_SKB_CB(skb)->has_seq = 0;
678 if (tunnel->version == L2TP_HDR_VER_2) {
679 if (hdrflags & L2TP_HDRFLAG_S) {
680 ns = ntohs(*(__be16 *) ptr);
682 nr = ntohs(*(__be16 *) ptr);
685 /* Store L2TP info in the skb */
686 L2TP_SKB_CB(skb)->ns = ns;
687 L2TP_SKB_CB(skb)->has_seq = 1;
689 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
690 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
691 session->name, ns, nr, session->nr);
693 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
694 u32 l2h = ntohl(*(__be32 *) ptr);
696 if (l2h & 0x40000000) {
697 ns = l2h & 0x00ffffff;
699 /* Store L2TP info in the skb */
700 L2TP_SKB_CB(skb)->ns = ns;
701 L2TP_SKB_CB(skb)->has_seq = 1;
703 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
704 "%s: recv data ns=%u, session nr=%u\n",
705 session->name, ns, session->nr);
709 /* Advance past L2-specific header, if present */
710 ptr += session->l2specific_len;
712 if (L2TP_SKB_CB(skb)->has_seq) {
713 /* Received a packet with sequence numbers. If we're the LNS,
714 * check if we sre sending sequence numbers and if not,
717 if ((!session->lns_mode) && (!session->send_seq)) {
718 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
719 "%s: requested to enable seq numbers by LNS\n",
721 session->send_seq = -1;
722 l2tp_session_set_header_len(session, tunnel->version);
725 /* No sequence numbers.
726 * If user has configured mandatory sequence numbers, discard.
728 if (session->recv_seq) {
729 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
730 "%s: recv data has no seq numbers when required. "
731 "Discarding\n", session->name);
732 session->stats.rx_seq_discards++;
736 /* If we're the LAC and we're sending sequence numbers, the
737 * LNS has requested that we no longer send sequence numbers.
738 * If we're the LNS and we're sending sequence numbers, the
739 * LAC is broken. Discard the frame.
741 if ((!session->lns_mode) && (session->send_seq)) {
742 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
743 "%s: requested to disable seq numbers by LNS\n",
745 session->send_seq = 0;
746 l2tp_session_set_header_len(session, tunnel->version);
747 } else if (session->send_seq) {
748 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
749 "%s: recv data has no seq numbers when required. "
750 "Discarding\n", session->name);
751 session->stats.rx_seq_discards++;
756 /* Session data offset is handled differently for L2TPv2 and
757 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
758 * the header. For L2TPv3, the offset is negotiated using AVPs
759 * in the session setup control protocol.
761 if (tunnel->version == L2TP_HDR_VER_2) {
762 /* If offset bit set, skip it. */
763 if (hdrflags & L2TP_HDRFLAG_O) {
764 offset = ntohs(*(__be16 *)ptr);
768 ptr += session->offset;
771 if (!pskb_may_pull(skb, offset))
774 __skb_pull(skb, offset);
776 /* If caller wants to process the payload before we queue the
780 if ((*payload_hook)(skb))
783 /* Prepare skb for adding to the session's reorder_q. Hold
784 * packets for max reorder_timeout or 1 second if not
787 L2TP_SKB_CB(skb)->length = length;
788 L2TP_SKB_CB(skb)->expires = jiffies +
789 (session->reorder_timeout ? session->reorder_timeout : HZ);
791 /* Add packet to the session's receive queue. Reordering is done here, if
792 * enabled. Saved L2TP protocol info is stored in skb->sb[].
794 if (L2TP_SKB_CB(skb)->has_seq) {
795 if (session->reorder_timeout != 0) {
796 /* Packet reordering enabled. Add skb to session's
797 * reorder queue, in order of ns.
799 l2tp_recv_queue_skb(session, skb);
801 /* Packet reordering disabled. Discard out-of-sequence
804 if (L2TP_SKB_CB(skb)->ns != session->nr) {
805 session->stats.rx_seq_discards++;
806 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
807 "%s: oos pkt %u len %d discarded, "
808 "waiting for %u, reorder_q_len=%d\n",
809 session->name, L2TP_SKB_CB(skb)->ns,
810 L2TP_SKB_CB(skb)->length, session->nr,
811 skb_queue_len(&session->reorder_q));
814 skb_queue_tail(&session->reorder_q, skb);
817 /* No sequence numbers. Add the skb to the tail of the
818 * reorder queue. This ensures that it will be
819 * delivered after all previous sequenced skbs.
821 skb_queue_tail(&session->reorder_q, skb);
824 /* Try to dequeue as many skbs from reorder_q as we can. */
825 l2tp_recv_dequeue(session);
830 session->stats.rx_errors++;
834 (*session->deref)(session);
836 EXPORT_SYMBOL(l2tp_recv_common);
838 /* Drop skbs from the session's reorder_q
840 int l2tp_session_queue_purge(struct l2tp_session *session)
842 struct sk_buff *skb = NULL;
844 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
845 while ((skb = skb_dequeue(&session->reorder_q))) {
846 session->stats.rx_errors++;
849 (*session->deref)(session);
853 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge);
855 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
856 * here. The skb is not on a list when we get here.
857 * Returns 0 if the packet was a data packet and was successfully passed on.
858 * Returns 1 if the packet was not a good data packet and could not be
859 * forwarded. All such packets are passed up to userspace to deal with.
861 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
862 int (*payload_hook)(struct sk_buff *skb))
864 struct l2tp_session *session = NULL;
865 unsigned char *ptr, *optr;
867 u32 tunnel_id, session_id;
872 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
873 goto discard_bad_csum;
875 /* UDP always verifies the packet length. */
876 __skb_pull(skb, sizeof(struct udphdr));
879 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
880 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
881 "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
885 /* Trace packet contents, if enabled */
886 if (tunnel->debug & L2TP_MSG_DATA) {
887 length = min(32u, skb->len);
888 if (!pskb_may_pull(skb, length))
891 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
895 printk(" %02X", skb->data[offset]);
896 } while (++offset < length);
901 /* Point to L2TP header */
902 optr = ptr = skb->data;
904 /* Get L2TP header flags */
905 hdrflags = ntohs(*(__be16 *) ptr);
907 /* Check protocol version */
908 version = hdrflags & L2TP_HDR_VER_MASK;
909 if (version != tunnel->version) {
910 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
911 "%s: recv protocol version mismatch: got %d expected %d\n",
912 tunnel->name, version, tunnel->version);
916 /* Get length of L2TP packet */
919 /* If type is control packet, it is handled by userspace. */
920 if (hdrflags & L2TP_HDRFLAG_T) {
921 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
922 "%s: recv control packet, len=%d\n", tunnel->name, length);
929 if (tunnel->version == L2TP_HDR_VER_2) {
930 /* If length is present, skip it */
931 if (hdrflags & L2TP_HDRFLAG_L)
934 /* Extract tunnel and session ID */
935 tunnel_id = ntohs(*(__be16 *) ptr);
937 session_id = ntohs(*(__be16 *) ptr);
940 ptr += 2; /* skip reserved bits */
941 tunnel_id = tunnel->tunnel_id;
942 session_id = ntohl(*(__be32 *) ptr);
946 /* Find the session context */
947 session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id, true);
948 if (!session || !session->recv_skb) {
951 session->deref(session);
952 l2tp_session_dec_refcount(session);
955 /* Not found? Pass to userspace to deal with */
956 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
957 "%s: no session found (%u/%u). Passing up.\n",
958 tunnel->name, tunnel_id, session_id);
962 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
963 l2tp_session_dec_refcount(session);
968 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
969 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
970 tunnel->stats.rx_errors++;
976 /* Put UDP header back */
977 __skb_push(skb, sizeof(struct udphdr));
982 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
986 * >0: skb should be passed up to userspace as UDP.
988 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
990 struct l2tp_tunnel *tunnel;
992 tunnel = l2tp_sock_to_tunnel(sk);
996 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
997 "%s: received %d bytes\n", tunnel->name, skb->len);
999 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
1010 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
1012 /************************************************************************
1014 ***********************************************************************/
1016 /* Build an L2TP header for the session into the buffer provided.
1018 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
1020 struct l2tp_tunnel *tunnel = session->tunnel;
1023 u16 flags = L2TP_HDR_VER_2;
1024 u32 tunnel_id = tunnel->peer_tunnel_id;
1025 u32 session_id = session->peer_session_id;
1027 if (session->send_seq)
1028 flags |= L2TP_HDRFLAG_S;
1030 /* Setup L2TP header. */
1031 *bufp++ = htons(flags);
1032 *bufp++ = htons(tunnel_id);
1033 *bufp++ = htons(session_id);
1034 if (session->send_seq) {
1035 *bufp++ = htons(session->ns);
1038 session->ns &= 0xffff;
1039 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
1040 "%s: updated ns to %u\n", session->name, session->ns);
1046 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
1048 struct l2tp_tunnel *tunnel = session->tunnel;
1052 /* Setup L2TP header. The header differs slightly for UDP and
1053 * IP encapsulations. For UDP, there is 4 bytes of flags.
1055 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1056 u16 flags = L2TP_HDR_VER_3;
1057 *((__be16 *) bufp) = htons(flags);
1059 *((__be16 *) bufp) = 0;
1063 *((__be32 *) bufp) = htonl(session->peer_session_id);
1065 if (session->cookie_len) {
1066 memcpy(bufp, &session->cookie[0], session->cookie_len);
1067 bufp += session->cookie_len;
1069 if (session->l2specific_len) {
1070 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
1072 if (session->send_seq) {
1073 l2h = 0x40000000 | session->ns;
1075 session->ns &= 0xffffff;
1076 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
1077 "%s: updated ns to %u\n", session->name, session->ns);
1080 *((__be32 *) bufp) = htonl(l2h);
1082 bufp += session->l2specific_len;
1084 if (session->offset)
1085 bufp += session->offset;
1090 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1091 struct flowi *fl, size_t data_len)
1093 struct l2tp_tunnel *tunnel = session->tunnel;
1094 unsigned int len = skb->len;
1098 if (session->send_seq)
1099 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
1100 "%s: send %Zd bytes, ns=%u\n", session->name,
1101 data_len, session->ns - 1);
1103 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
1104 "%s: send %Zd bytes\n", session->name, data_len);
1106 if (session->debug & L2TP_MSG_DATA) {
1108 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1109 unsigned char *datap = skb->data + uhlen;
1111 printk(KERN_DEBUG "%s: xmit:", session->name);
1112 for (i = 0; i < (len - uhlen); i++) {
1113 printk(" %02X", *datap++);
1122 /* Queue the packet to IP for output */
1124 error = ip_queue_xmit(skb, fl);
1128 tunnel->stats.tx_packets++;
1129 tunnel->stats.tx_bytes += len;
1130 session->stats.tx_packets++;
1131 session->stats.tx_bytes += len;
1133 tunnel->stats.tx_errors++;
1134 session->stats.tx_errors++;
1140 /* Automatically called when the skb is freed.
1142 static void l2tp_sock_wfree(struct sk_buff *skb)
1147 /* For data skbs that we transmit, we associate with the tunnel socket
1148 * but don't do accounting.
1150 static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1154 skb->destructor = l2tp_sock_wfree;
1157 /* If caller requires the skb to have a ppp header, the header must be
1158 * inserted in the skb data before calling this function.
1160 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1162 int data_len = skb->len;
1163 struct l2tp_tunnel *tunnel = session->tunnel;
1164 struct sock *sk = tunnel->sock;
1167 struct inet_sock *inet;
1172 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1175 /* Check that there's enough headroom in the skb to insert IP,
1176 * UDP and L2TP headers. If not enough, expand it to
1177 * make room. Adjust truesize.
1179 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1181 old_headroom = skb_headroom(skb);
1182 if (skb_cow_head(skb, headroom)) {
1187 new_headroom = skb_headroom(skb);
1189 skb->truesize += new_headroom - old_headroom;
1191 /* Setup L2TP header */
1192 session->build_header(session, __skb_push(skb, hdr_len));
1194 /* Reset skb netfilter state */
1195 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1196 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1201 if (sock_owned_by_user(sk)) {
1206 /* Get routing info from the tunnel socket */
1208 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
1211 fl = &inet->cork.fl;
1212 switch (tunnel->encap) {
1213 case L2TP_ENCAPTYPE_UDP:
1214 /* Setup UDP header */
1215 __skb_push(skb, sizeof(*uh));
1216 skb_reset_transport_header(skb);
1218 uh->source = inet->inet_sport;
1219 uh->dest = inet->inet_dport;
1220 udp_len = uhlen + hdr_len + data_len;
1221 uh->len = htons(udp_len);
1224 /* Calculate UDP checksum if configured to do so */
1225 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1226 skb->ip_summed = CHECKSUM_NONE;
1227 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1228 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1229 skb->ip_summed = CHECKSUM_COMPLETE;
1230 csum = skb_checksum(skb, 0, udp_len, 0);
1231 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1233 udp_len, IPPROTO_UDP, csum);
1235 uh->check = CSUM_MANGLED_0;
1237 skb->ip_summed = CHECKSUM_PARTIAL;
1238 skb->csum_start = skb_transport_header(skb) - skb->head;
1239 skb->csum_offset = offsetof(struct udphdr, check);
1240 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1242 udp_len, IPPROTO_UDP, 0);
1246 case L2TP_ENCAPTYPE_IP:
1250 l2tp_skb_set_owner_w(skb, sk);
1252 l2tp_xmit_core(session, skb, fl, data_len);
1259 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1261 /*****************************************************************************
1262 * Tinnel and session create/destroy.
1263 *****************************************************************************/
1265 /* Tunnel socket destruct hook.
1266 * The tunnel context is deleted only when all session sockets have been
1269 static void l2tp_tunnel_destruct(struct sock *sk)
1271 struct l2tp_tunnel *tunnel;
1273 tunnel = sk->sk_user_data;
1277 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1278 "%s: closing...\n", tunnel->name);
1280 /* Close all sessions */
1281 l2tp_tunnel_closeall(tunnel);
1283 switch (tunnel->encap) {
1284 case L2TP_ENCAPTYPE_UDP:
1285 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1286 (udp_sk(sk))->encap_type = 0;
1287 (udp_sk(sk))->encap_rcv = NULL;
1289 case L2TP_ENCAPTYPE_IP:
1293 /* Remove hooks into tunnel socket */
1294 tunnel->sock = NULL;
1295 sk->sk_destruct = tunnel->old_sk_destruct;
1296 sk->sk_user_data = NULL;
1298 /* Call the original destructor */
1299 if (sk->sk_destruct)
1300 (*sk->sk_destruct)(sk);
1302 /* We're finished with the socket */
1303 l2tp_tunnel_dec_refcount(tunnel);
1309 /* When the tunnel is closed, all the attached sessions need to go too.
1311 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1314 struct hlist_node *walk;
1315 struct hlist_node *tmp;
1316 struct l2tp_session *session;
1318 BUG_ON(tunnel == NULL);
1320 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1321 "%s: closing all sessions...\n", tunnel->name);
1323 write_lock_bh(&tunnel->hlist_lock);
1324 tunnel->acpt_newsess = false;
1325 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1327 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1328 session = hlist_entry(walk, struct l2tp_session, hlist);
1330 PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO,
1331 "%s: closing session\n", session->name);
1333 hlist_del_init(&session->hlist);
1335 /* Since we should hold the sock lock while
1336 * doing any unbinding, we need to release the
1337 * lock we're holding before taking that lock.
1338 * Hold a reference to the sock so it doesn't
1339 * disappear as we're jumping between locks.
1341 if (session->ref != NULL)
1342 (*session->ref)(session);
1344 write_unlock_bh(&tunnel->hlist_lock);
1346 if (tunnel->version != L2TP_HDR_VER_2) {
1347 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1349 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1350 hlist_del_init_rcu(&session->global_hlist);
1351 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1355 l2tp_session_queue_purge(session);
1357 if (session->session_close != NULL)
1358 (*session->session_close)(session);
1360 if (session->deref != NULL)
1361 (*session->deref)(session);
1363 write_lock_bh(&tunnel->hlist_lock);
1365 /* Now restart from the beginning of this hash
1366 * chain. We always remove a session from the
1367 * list so we are guaranteed to make forward
1373 write_unlock_bh(&tunnel->hlist_lock);
1376 /* Really kill the tunnel.
1377 * Come here only when all sessions have been cleared from the tunnel.
1379 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
1381 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1383 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1384 BUG_ON(tunnel->sock != NULL);
1386 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1387 "%s: free...\n", tunnel->name);
1389 /* Remove from tunnel list */
1390 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1391 list_del_rcu(&tunnel->list);
1392 kfree_rcu(tunnel, rcu);
1393 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1395 atomic_dec(&l2tp_tunnel_count);
1397 EXPORT_SYMBOL_GPL(l2tp_tunnel_free);
1399 /* Create a socket for the tunnel, if one isn't set up by
1400 * userspace. This is used for static tunnels where there is no
1401 * managing L2TP daemon.
1403 static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1406 struct sockaddr_in udp_addr;
1407 struct sockaddr_l2tpip ip_addr;
1408 struct socket *sock = NULL;
1410 switch (cfg->encap) {
1411 case L2TP_ENCAPTYPE_UDP:
1412 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1418 memset(&udp_addr, 0, sizeof(udp_addr));
1419 udp_addr.sin_family = AF_INET;
1420 udp_addr.sin_addr = cfg->local_ip;
1421 udp_addr.sin_port = htons(cfg->local_udp_port);
1422 err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr));
1426 udp_addr.sin_family = AF_INET;
1427 udp_addr.sin_addr = cfg->peer_ip;
1428 udp_addr.sin_port = htons(cfg->peer_udp_port);
1429 err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0);
1433 if (!cfg->use_udp_checksums)
1434 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1438 case L2TP_ENCAPTYPE_IP:
1439 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
1445 memset(&ip_addr, 0, sizeof(ip_addr));
1446 ip_addr.l2tp_family = AF_INET;
1447 ip_addr.l2tp_addr = cfg->local_ip;
1448 ip_addr.l2tp_conn_id = tunnel_id;
1449 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr));
1453 ip_addr.l2tp_family = AF_INET;
1454 ip_addr.l2tp_addr = cfg->peer_ip;
1455 ip_addr.l2tp_conn_id = peer_tunnel_id;
1456 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0);
1467 if ((err < 0) && sock) {
1475 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)
1477 struct l2tp_tunnel *tunnel = NULL;
1479 struct socket *sock = NULL;
1480 struct sock *sk = NULL;
1481 struct l2tp_net *pn;
1482 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1484 /* Get the tunnel socket from the fd, which was opened by
1485 * the userspace L2TP daemon. If not specified, create a
1489 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1494 sock = sockfd_lookup(fd, &err);
1496 printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1497 tunnel_id, fd, err);
1507 /* Quick sanity checks */
1508 err = -EPROTONOSUPPORT;
1509 if (sk->sk_type != SOCK_DGRAM) {
1510 pr_debug("tunl %hu: fd %d wrong socket type\n",
1515 case L2TP_ENCAPTYPE_UDP:
1516 if (sk->sk_protocol != IPPROTO_UDP) {
1517 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1518 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1522 case L2TP_ENCAPTYPE_IP:
1523 if (sk->sk_protocol != IPPROTO_L2TP) {
1524 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1525 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1531 /* Check if this socket has already been prepped */
1532 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1533 if (tunnel != NULL) {
1534 /* This socket has already been prepped */
1539 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1540 if (tunnel == NULL) {
1545 tunnel->version = version;
1546 tunnel->tunnel_id = tunnel_id;
1547 tunnel->peer_tunnel_id = peer_tunnel_id;
1548 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1550 tunnel->magic = L2TP_TUNNEL_MAGIC;
1551 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1552 rwlock_init(&tunnel->hlist_lock);
1553 tunnel->acpt_newsess = true;
1555 /* The net we belong to */
1556 tunnel->l2tp_net = net;
1557 pn = l2tp_pernet(net);
1560 tunnel->debug = cfg->debug;
1562 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1563 tunnel->encap = encap;
1564 if (encap == L2TP_ENCAPTYPE_UDP) {
1565 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1566 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1567 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1570 sk->sk_user_data = tunnel;
1572 /* Hook on the tunnel socket destructor so that we can cleanup
1573 * if the tunnel socket goes away.
1575 tunnel->old_sk_destruct = sk->sk_destruct;
1576 sk->sk_destruct = &l2tp_tunnel_destruct;
1578 sk->sk_allocation = GFP_ATOMIC;
1580 /* Add tunnel to our list */
1581 INIT_LIST_HEAD(&tunnel->list);
1582 atomic_inc(&l2tp_tunnel_count);
1584 /* Bump the reference count. The tunnel context is deleted
1585 * only when this drops to zero. Must be done before list insertion
1587 l2tp_tunnel_inc_refcount(tunnel);
1588 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1589 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1590 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1597 /* If tunnel's socket was created by the kernel, it doesn't
1600 if (sock && sock->file)
1605 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1607 /* This function is used by the netlink TUNNEL_DELETE command.
1609 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1612 struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL;
1614 /* Force the tunnel socket to close. This will eventually
1615 * cause the tunnel to be deleted via the normal socket close
1616 * mechanisms when userspace closes the tunnel socket.
1619 err = inet_shutdown(sock, 2);
1621 /* If the tunnel's socket was created by the kernel,
1622 * close the socket here since the socket was not
1623 * created by userspace.
1625 if (sock->file == NULL)
1626 err = inet_release(sock);
1631 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1633 /* Really kill the session.
1635 void l2tp_session_free(struct l2tp_session *session)
1637 struct l2tp_tunnel *tunnel;
1639 BUG_ON(atomic_read(&session->ref_count) != 0);
1641 tunnel = session->tunnel;
1642 if (tunnel != NULL) {
1643 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1645 /* Delete the session from the hash */
1646 write_lock_bh(&tunnel->hlist_lock);
1647 hlist_del_init(&session->hlist);
1648 write_unlock_bh(&tunnel->hlist_lock);
1650 /* Unlink from the global hash if not L2TPv2 */
1651 if (tunnel->version != L2TP_HDR_VER_2) {
1652 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1654 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1655 hlist_del_init_rcu(&session->global_hlist);
1656 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1660 if (session->session_id != 0)
1661 atomic_dec(&l2tp_session_count);
1663 sock_put(tunnel->sock);
1665 /* This will delete the tunnel context if this
1666 * is the last session on the tunnel.
1668 session->tunnel = NULL;
1669 l2tp_tunnel_dec_refcount(tunnel);
1676 EXPORT_SYMBOL_GPL(l2tp_session_free);
1678 /* This function is used by the netlink SESSION_DELETE command and by
1681 int l2tp_session_delete(struct l2tp_session *session)
1683 l2tp_session_queue_purge(session);
1685 if (session->session_close != NULL)
1686 (*session->session_close)(session);
1688 l2tp_session_dec_refcount(session);
1692 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1695 /* We come here whenever a session's send_seq, cookie_len or
1696 * l2specific_len parameters are set.
1698 static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1700 if (version == L2TP_HDR_VER_2) {
1701 session->hdr_len = 6;
1702 if (session->send_seq)
1703 session->hdr_len += 4;
1705 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1706 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1707 session->hdr_len += 4;
1712 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)
1714 struct l2tp_session *session;
1716 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1717 if (session != NULL) {
1718 session->magic = L2TP_SESSION_MAGIC;
1719 session->tunnel = tunnel;
1721 session->session_id = session_id;
1722 session->peer_session_id = peer_session_id;
1725 sprintf(&session->name[0], "sess %u/%u",
1726 tunnel->tunnel_id, session->session_id);
1728 skb_queue_head_init(&session->reorder_q);
1730 INIT_HLIST_NODE(&session->hlist);
1731 INIT_HLIST_NODE(&session->global_hlist);
1733 /* Inherit debug options from tunnel */
1734 session->debug = tunnel->debug;
1737 session->pwtype = cfg->pw_type;
1738 session->debug = cfg->debug;
1739 session->mtu = cfg->mtu;
1740 session->mru = cfg->mru;
1741 session->send_seq = cfg->send_seq;
1742 session->recv_seq = cfg->recv_seq;
1743 session->lns_mode = cfg->lns_mode;
1744 session->reorder_timeout = cfg->reorder_timeout;
1745 session->offset = cfg->offset;
1746 session->l2specific_type = cfg->l2specific_type;
1747 session->l2specific_len = cfg->l2specific_len;
1748 session->cookie_len = cfg->cookie_len;
1749 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1750 session->peer_cookie_len = cfg->peer_cookie_len;
1751 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1754 if (tunnel->version == L2TP_HDR_VER_2)
1755 session->build_header = l2tp_build_l2tpv2_header;
1757 session->build_header = l2tp_build_l2tpv3_header;
1759 l2tp_session_set_header_len(session, tunnel->version);
1761 l2tp_session_inc_refcount(session);
1766 return ERR_PTR(-ENOMEM);
1768 EXPORT_SYMBOL_GPL(l2tp_session_create);
1770 /*****************************************************************************
1772 *****************************************************************************/
1774 static __net_init int l2tp_init_net(struct net *net)
1776 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1779 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1780 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1782 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1783 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1785 spin_lock_init(&pn->l2tp_session_hlist_lock);
1790 static struct pernet_operations l2tp_net_ops = {
1791 .init = l2tp_init_net,
1793 .size = sizeof(struct l2tp_net),
1796 static int __init l2tp_init(void)
1800 rc = register_pernet_device(&l2tp_net_ops);
1804 printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION);
1810 static void __exit l2tp_exit(void)
1812 unregister_pernet_device(&l2tp_net_ops);
1815 module_init(l2tp_init);
1816 module_exit(l2tp_exit);
1818 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1819 MODULE_DESCRIPTION("L2TP core");
1820 MODULE_LICENSE("GPL");
1821 MODULE_VERSION(L2TP_DRV_VERSION);