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 static int l2tp_session_add_to_tunnel(struct l2tp_tunnel *tunnel,
331 struct l2tp_session *session)
333 struct l2tp_session *session_walk;
334 struct hlist_head *g_head;
335 struct hlist_head *head;
337 struct hlist_node *walk;
339 head = l2tp_session_id_hash(tunnel, session->session_id);
341 write_lock_bh(&tunnel->hlist_lock);
342 hlist_for_each_entry(session_walk, walk, head, hlist)
343 if (session_walk->session_id == session->session_id)
346 if (tunnel->version == L2TP_HDR_VER_3) {
347 pn = l2tp_pernet(tunnel->l2tp_net);
348 g_head = l2tp_session_id_hash_2(l2tp_pernet(tunnel->l2tp_net),
349 session->session_id);
351 spin_lock_bh(&pn->l2tp_session_hlist_lock);
352 hlist_for_each_entry(session_walk, walk, g_head, global_hlist)
353 if (session_walk->session_id == session->session_id)
356 hlist_add_head_rcu(&session->global_hlist, g_head);
357 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
360 hlist_add_head(&session->hlist, head);
361 write_unlock_bh(&tunnel->hlist_lock);
366 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
368 write_unlock_bh(&tunnel->hlist_lock);
373 /* Lookup a tunnel by id
375 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
377 struct l2tp_tunnel *tunnel;
378 struct l2tp_net *pn = l2tp_pernet(net);
381 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
382 if (tunnel->tunnel_id == tunnel_id) {
383 rcu_read_unlock_bh();
387 rcu_read_unlock_bh();
391 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
393 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
395 struct l2tp_net *pn = l2tp_pernet(net);
396 struct l2tp_tunnel *tunnel;
400 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
402 rcu_read_unlock_bh();
407 rcu_read_unlock_bh();
411 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
413 /*****************************************************************************
414 * Receive data handling
415 *****************************************************************************/
417 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
420 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
422 struct sk_buff *skbp;
424 u32 ns = L2TP_SKB_CB(skb)->ns;
426 spin_lock_bh(&session->reorder_q.lock);
427 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
428 if (L2TP_SKB_CB(skbp)->ns > ns) {
429 __skb_queue_before(&session->reorder_q, skbp, skb);
430 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
431 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
432 session->name, ns, L2TP_SKB_CB(skbp)->ns,
433 skb_queue_len(&session->reorder_q));
434 session->stats.rx_oos_packets++;
439 __skb_queue_tail(&session->reorder_q, skb);
442 spin_unlock_bh(&session->reorder_q.lock);
445 /* Dequeue a single skb.
447 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
449 struct l2tp_tunnel *tunnel = session->tunnel;
450 int length = L2TP_SKB_CB(skb)->length;
452 /* We're about to requeue the skb, so return resources
453 * to its current owner (a socket receive buffer).
457 tunnel->stats.rx_packets++;
458 tunnel->stats.rx_bytes += length;
459 session->stats.rx_packets++;
460 session->stats.rx_bytes += length;
462 if (L2TP_SKB_CB(skb)->has_seq) {
465 if (tunnel->version == L2TP_HDR_VER_2)
466 session->nr &= 0xffff;
468 session->nr &= 0xffffff;
470 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
471 "%s: updated nr to %hu\n", session->name, session->nr);
474 /* call private receive handler */
475 if (session->recv_skb != NULL)
476 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
481 (*session->deref)(session);
484 /* Dequeue skbs from the session's reorder_q, subject to packet order.
485 * Skbs that have been in the queue for too long are simply discarded.
487 static void l2tp_recv_dequeue(struct l2tp_session *session)
492 /* If the pkt at the head of the queue has the nr that we
493 * expect to send up next, dequeue it and any other
494 * in-sequence packets behind it.
497 spin_lock_bh(&session->reorder_q.lock);
498 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
499 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
500 session->stats.rx_seq_discards++;
501 session->stats.rx_errors++;
502 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
503 "%s: oos pkt %u len %d discarded (too old), "
504 "waiting for %u, reorder_q_len=%d\n",
505 session->name, L2TP_SKB_CB(skb)->ns,
506 L2TP_SKB_CB(skb)->length, session->nr,
507 skb_queue_len(&session->reorder_q));
508 __skb_unlink(skb, &session->reorder_q);
511 (*session->deref)(session);
515 if (L2TP_SKB_CB(skb)->has_seq) {
516 if (L2TP_SKB_CB(skb)->ns != session->nr) {
517 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
518 "%s: holding oos pkt %u len %d, "
519 "waiting for %u, reorder_q_len=%d\n",
520 session->name, L2TP_SKB_CB(skb)->ns,
521 L2TP_SKB_CB(skb)->length, session->nr,
522 skb_queue_len(&session->reorder_q));
526 __skb_unlink(skb, &session->reorder_q);
528 /* Process the skb. We release the queue lock while we
529 * do so to let other contexts process the queue.
531 spin_unlock_bh(&session->reorder_q.lock);
532 l2tp_recv_dequeue_skb(session, skb);
537 spin_unlock_bh(&session->reorder_q.lock);
540 static inline int l2tp_verify_udp_checksum(struct sock *sk,
543 struct udphdr *uh = udp_hdr(skb);
544 u16 ulen = ntohs(uh->len);
545 struct inet_sock *inet;
548 if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
552 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
555 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
556 !csum_fold(csum_add(psum, skb->csum)))
561 return __skb_checksum_complete(skb);
564 /* Do receive processing of L2TP data frames. We handle both L2TPv2
565 * and L2TPv3 data frames here.
567 * L2TPv2 Data Message Header
570 * 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
571 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
572 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
573 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
574 * | Tunnel ID | Session ID |
575 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
576 * | Ns (opt) | Nr (opt) |
577 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
578 * | Offset Size (opt) | Offset pad... (opt)
579 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
581 * Data frames are marked by T=0. All other fields are the same as
582 * those in L2TP control frames.
584 * L2TPv3 Data Message Header
586 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
587 * | L2TP Session Header |
588 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
589 * | L2-Specific Sublayer |
590 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
591 * | Tunnel Payload ...
592 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
594 * L2TPv3 Session Header Over IP
597 * 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
598 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
600 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
601 * | Cookie (optional, maximum 64 bits)...
602 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
604 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
606 * L2TPv3 L2-Specific Sublayer Format
609 * 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
610 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
611 * |x|S|x|x|x|x|x|x| Sequence Number |
612 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
614 * Cookie value, sublayer format and offset (pad) are negotiated with
615 * the peer when the session is set up. Unlike L2TPv2, we do not need
616 * to parse the packet header to determine if optional fields are
619 * Caller must already have parsed the frame and determined that it is
620 * a data (not control) frame before coming here. Fields up to the
621 * session-id have already been parsed and ptr points to the data
622 * after the session-id.
624 * session->ref() must have been called prior to l2tp_recv_common().
625 * session->deref() will be called automatically after skb is processed.
627 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
628 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
629 int length, int (*payload_hook)(struct sk_buff *skb))
631 struct l2tp_tunnel *tunnel = session->tunnel;
635 /* Parse and check optional cookie */
636 if (session->peer_cookie_len > 0) {
637 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
638 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
639 "%s: cookie mismatch (%u/%u). Discarding.\n",
640 tunnel->name, tunnel->tunnel_id, session->session_id);
641 session->stats.rx_cookie_discards++;
644 ptr += session->peer_cookie_len;
647 /* Handle the optional sequence numbers. Sequence numbers are
648 * in different places for L2TPv2 and L2TPv3.
650 * If we are the LAC, enable/disable sequence numbers under
651 * the control of the LNS. If no sequence numbers present but
652 * we were expecting them, discard frame.
655 L2TP_SKB_CB(skb)->has_seq = 0;
656 if (tunnel->version == L2TP_HDR_VER_2) {
657 if (hdrflags & L2TP_HDRFLAG_S) {
658 ns = ntohs(*(__be16 *) ptr);
660 nr = ntohs(*(__be16 *) ptr);
663 /* Store L2TP info in the skb */
664 L2TP_SKB_CB(skb)->ns = ns;
665 L2TP_SKB_CB(skb)->has_seq = 1;
667 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
668 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
669 session->name, ns, nr, session->nr);
671 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
672 u32 l2h = ntohl(*(__be32 *) ptr);
674 if (l2h & 0x40000000) {
675 ns = l2h & 0x00ffffff;
677 /* Store L2TP info in the skb */
678 L2TP_SKB_CB(skb)->ns = ns;
679 L2TP_SKB_CB(skb)->has_seq = 1;
681 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
682 "%s: recv data ns=%u, session nr=%u\n",
683 session->name, ns, session->nr);
687 /* Advance past L2-specific header, if present */
688 ptr += session->l2specific_len;
690 if (L2TP_SKB_CB(skb)->has_seq) {
691 /* Received a packet with sequence numbers. If we're the LNS,
692 * check if we sre sending sequence numbers and if not,
695 if ((!session->lns_mode) && (!session->send_seq)) {
696 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
697 "%s: requested to enable seq numbers by LNS\n",
699 session->send_seq = -1;
700 l2tp_session_set_header_len(session, tunnel->version);
703 /* No sequence numbers.
704 * If user has configured mandatory sequence numbers, discard.
706 if (session->recv_seq) {
707 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
708 "%s: recv data has no seq numbers when required. "
709 "Discarding\n", session->name);
710 session->stats.rx_seq_discards++;
714 /* If we're the LAC and we're sending sequence numbers, the
715 * LNS has requested that we no longer send sequence numbers.
716 * If we're the LNS and we're sending sequence numbers, the
717 * LAC is broken. Discard the frame.
719 if ((!session->lns_mode) && (session->send_seq)) {
720 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
721 "%s: requested to disable seq numbers by LNS\n",
723 session->send_seq = 0;
724 l2tp_session_set_header_len(session, tunnel->version);
725 } else if (session->send_seq) {
726 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
727 "%s: recv data has no seq numbers when required. "
728 "Discarding\n", session->name);
729 session->stats.rx_seq_discards++;
734 /* Session data offset is handled differently for L2TPv2 and
735 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
736 * the header. For L2TPv3, the offset is negotiated using AVPs
737 * in the session setup control protocol.
739 if (tunnel->version == L2TP_HDR_VER_2) {
740 /* If offset bit set, skip it. */
741 if (hdrflags & L2TP_HDRFLAG_O) {
742 offset = ntohs(*(__be16 *)ptr);
746 ptr += session->offset;
749 if (!pskb_may_pull(skb, offset))
752 __skb_pull(skb, offset);
754 /* If caller wants to process the payload before we queue the
758 if ((*payload_hook)(skb))
761 /* Prepare skb for adding to the session's reorder_q. Hold
762 * packets for max reorder_timeout or 1 second if not
765 L2TP_SKB_CB(skb)->length = length;
766 L2TP_SKB_CB(skb)->expires = jiffies +
767 (session->reorder_timeout ? session->reorder_timeout : HZ);
769 /* Add packet to the session's receive queue. Reordering is done here, if
770 * enabled. Saved L2TP protocol info is stored in skb->sb[].
772 if (L2TP_SKB_CB(skb)->has_seq) {
773 if (session->reorder_timeout != 0) {
774 /* Packet reordering enabled. Add skb to session's
775 * reorder queue, in order of ns.
777 l2tp_recv_queue_skb(session, skb);
779 /* Packet reordering disabled. Discard out-of-sequence
782 if (L2TP_SKB_CB(skb)->ns != session->nr) {
783 session->stats.rx_seq_discards++;
784 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
785 "%s: oos pkt %u len %d discarded, "
786 "waiting for %u, reorder_q_len=%d\n",
787 session->name, L2TP_SKB_CB(skb)->ns,
788 L2TP_SKB_CB(skb)->length, session->nr,
789 skb_queue_len(&session->reorder_q));
792 skb_queue_tail(&session->reorder_q, skb);
795 /* No sequence numbers. Add the skb to the tail of the
796 * reorder queue. This ensures that it will be
797 * delivered after all previous sequenced skbs.
799 skb_queue_tail(&session->reorder_q, skb);
802 /* Try to dequeue as many skbs from reorder_q as we can. */
803 l2tp_recv_dequeue(session);
808 session->stats.rx_errors++;
812 (*session->deref)(session);
814 EXPORT_SYMBOL(l2tp_recv_common);
816 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
817 * here. The skb is not on a list when we get here.
818 * Returns 0 if the packet was a data packet and was successfully passed on.
819 * Returns 1 if the packet was not a good data packet and could not be
820 * forwarded. All such packets are passed up to userspace to deal with.
822 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
823 int (*payload_hook)(struct sk_buff *skb))
825 struct l2tp_session *session = NULL;
826 unsigned char *ptr, *optr;
828 u32 tunnel_id, session_id;
833 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
834 goto discard_bad_csum;
836 /* UDP always verifies the packet length. */
837 __skb_pull(skb, sizeof(struct udphdr));
840 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
841 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
842 "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
846 /* Trace packet contents, if enabled */
847 if (tunnel->debug & L2TP_MSG_DATA) {
848 length = min(32u, skb->len);
849 if (!pskb_may_pull(skb, length))
852 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
856 printk(" %02X", skb->data[offset]);
857 } while (++offset < length);
862 /* Point to L2TP header */
863 optr = ptr = skb->data;
865 /* Get L2TP header flags */
866 hdrflags = ntohs(*(__be16 *) ptr);
868 /* Check protocol version */
869 version = hdrflags & L2TP_HDR_VER_MASK;
870 if (version != tunnel->version) {
871 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
872 "%s: recv protocol version mismatch: got %d expected %d\n",
873 tunnel->name, version, tunnel->version);
877 /* Get length of L2TP packet */
880 /* If type is control packet, it is handled by userspace. */
881 if (hdrflags & L2TP_HDRFLAG_T) {
882 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
883 "%s: recv control packet, len=%d\n", tunnel->name, length);
890 if (tunnel->version == L2TP_HDR_VER_2) {
891 /* If length is present, skip it */
892 if (hdrflags & L2TP_HDRFLAG_L)
895 /* Extract tunnel and session ID */
896 tunnel_id = ntohs(*(__be16 *) ptr);
898 session_id = ntohs(*(__be16 *) ptr);
901 ptr += 2; /* skip reserved bits */
902 tunnel_id = tunnel->tunnel_id;
903 session_id = ntohl(*(__be32 *) ptr);
907 /* Find the session context */
908 session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id, true);
909 if (!session || !session->recv_skb) {
912 session->deref(session);
913 l2tp_session_dec_refcount(session);
916 /* Not found? Pass to userspace to deal with */
917 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
918 "%s: no session found (%u/%u). Passing up.\n",
919 tunnel->name, tunnel_id, session_id);
923 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
924 l2tp_session_dec_refcount(session);
929 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
930 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
931 tunnel->stats.rx_errors++;
937 /* Put UDP header back */
938 __skb_push(skb, sizeof(struct udphdr));
943 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
947 * >0: skb should be passed up to userspace as UDP.
949 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
951 struct l2tp_tunnel *tunnel;
953 tunnel = l2tp_sock_to_tunnel(sk);
957 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
958 "%s: received %d bytes\n", tunnel->name, skb->len);
960 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
971 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
973 /************************************************************************
975 ***********************************************************************/
977 /* Build an L2TP header for the session into the buffer provided.
979 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
981 struct l2tp_tunnel *tunnel = session->tunnel;
984 u16 flags = L2TP_HDR_VER_2;
985 u32 tunnel_id = tunnel->peer_tunnel_id;
986 u32 session_id = session->peer_session_id;
988 if (session->send_seq)
989 flags |= L2TP_HDRFLAG_S;
991 /* Setup L2TP header. */
992 *bufp++ = htons(flags);
993 *bufp++ = htons(tunnel_id);
994 *bufp++ = htons(session_id);
995 if (session->send_seq) {
996 *bufp++ = htons(session->ns);
999 session->ns &= 0xffff;
1000 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
1001 "%s: updated ns to %u\n", session->name, session->ns);
1007 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
1009 struct l2tp_tunnel *tunnel = session->tunnel;
1013 /* Setup L2TP header. The header differs slightly for UDP and
1014 * IP encapsulations. For UDP, there is 4 bytes of flags.
1016 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1017 u16 flags = L2TP_HDR_VER_3;
1018 *((__be16 *) bufp) = htons(flags);
1020 *((__be16 *) bufp) = 0;
1024 *((__be32 *) bufp) = htonl(session->peer_session_id);
1026 if (session->cookie_len) {
1027 memcpy(bufp, &session->cookie[0], session->cookie_len);
1028 bufp += session->cookie_len;
1030 if (session->l2specific_len) {
1031 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
1033 if (session->send_seq) {
1034 l2h = 0x40000000 | session->ns;
1036 session->ns &= 0xffffff;
1037 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
1038 "%s: updated ns to %u\n", session->name, session->ns);
1041 *((__be32 *) bufp) = htonl(l2h);
1043 bufp += session->l2specific_len;
1045 if (session->offset)
1046 bufp += session->offset;
1051 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1052 struct flowi *fl, size_t data_len)
1054 struct l2tp_tunnel *tunnel = session->tunnel;
1055 unsigned int len = skb->len;
1059 if (session->send_seq)
1060 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
1061 "%s: send %Zd bytes, ns=%u\n", session->name,
1062 data_len, session->ns - 1);
1064 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
1065 "%s: send %Zd bytes\n", session->name, data_len);
1067 if (session->debug & L2TP_MSG_DATA) {
1069 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1070 unsigned char *datap = skb->data + uhlen;
1072 printk(KERN_DEBUG "%s: xmit:", session->name);
1073 for (i = 0; i < (len - uhlen); i++) {
1074 printk(" %02X", *datap++);
1083 /* Queue the packet to IP for output */
1085 error = ip_queue_xmit(skb, fl);
1089 tunnel->stats.tx_packets++;
1090 tunnel->stats.tx_bytes += len;
1091 session->stats.tx_packets++;
1092 session->stats.tx_bytes += len;
1094 tunnel->stats.tx_errors++;
1095 session->stats.tx_errors++;
1101 /* Automatically called when the skb is freed.
1103 static void l2tp_sock_wfree(struct sk_buff *skb)
1108 /* For data skbs that we transmit, we associate with the tunnel socket
1109 * but don't do accounting.
1111 static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1115 skb->destructor = l2tp_sock_wfree;
1118 /* If caller requires the skb to have a ppp header, the header must be
1119 * inserted in the skb data before calling this function.
1121 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1123 int data_len = skb->len;
1124 struct l2tp_tunnel *tunnel = session->tunnel;
1125 struct sock *sk = tunnel->sock;
1128 struct inet_sock *inet;
1133 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1136 /* Check that there's enough headroom in the skb to insert IP,
1137 * UDP and L2TP headers. If not enough, expand it to
1138 * make room. Adjust truesize.
1140 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1142 old_headroom = skb_headroom(skb);
1143 if (skb_cow_head(skb, headroom)) {
1148 new_headroom = skb_headroom(skb);
1150 skb->truesize += new_headroom - old_headroom;
1152 /* Setup L2TP header */
1153 session->build_header(session, __skb_push(skb, hdr_len));
1155 /* Reset skb netfilter state */
1156 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1157 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1162 if (sock_owned_by_user(sk)) {
1167 /* Get routing info from the tunnel socket */
1169 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
1172 fl = &inet->cork.fl;
1173 switch (tunnel->encap) {
1174 case L2TP_ENCAPTYPE_UDP:
1175 /* Setup UDP header */
1176 __skb_push(skb, sizeof(*uh));
1177 skb_reset_transport_header(skb);
1179 uh->source = inet->inet_sport;
1180 uh->dest = inet->inet_dport;
1181 udp_len = uhlen + hdr_len + data_len;
1182 uh->len = htons(udp_len);
1185 /* Calculate UDP checksum if configured to do so */
1186 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1187 skb->ip_summed = CHECKSUM_NONE;
1188 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1189 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1190 skb->ip_summed = CHECKSUM_COMPLETE;
1191 csum = skb_checksum(skb, 0, udp_len, 0);
1192 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1194 udp_len, IPPROTO_UDP, csum);
1196 uh->check = CSUM_MANGLED_0;
1198 skb->ip_summed = CHECKSUM_PARTIAL;
1199 skb->csum_start = skb_transport_header(skb) - skb->head;
1200 skb->csum_offset = offsetof(struct udphdr, check);
1201 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1203 udp_len, IPPROTO_UDP, 0);
1207 case L2TP_ENCAPTYPE_IP:
1211 l2tp_skb_set_owner_w(skb, sk);
1213 l2tp_xmit_core(session, skb, fl, data_len);
1220 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1222 /*****************************************************************************
1223 * Tinnel and session create/destroy.
1224 *****************************************************************************/
1226 /* Tunnel socket destruct hook.
1227 * The tunnel context is deleted only when all session sockets have been
1230 static void l2tp_tunnel_destruct(struct sock *sk)
1232 struct l2tp_tunnel *tunnel;
1234 tunnel = sk->sk_user_data;
1238 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1239 "%s: closing...\n", tunnel->name);
1241 /* Close all sessions */
1242 l2tp_tunnel_closeall(tunnel);
1244 switch (tunnel->encap) {
1245 case L2TP_ENCAPTYPE_UDP:
1246 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1247 (udp_sk(sk))->encap_type = 0;
1248 (udp_sk(sk))->encap_rcv = NULL;
1250 case L2TP_ENCAPTYPE_IP:
1254 /* Remove hooks into tunnel socket */
1255 tunnel->sock = NULL;
1256 sk->sk_destruct = tunnel->old_sk_destruct;
1257 sk->sk_user_data = NULL;
1259 /* Call the original destructor */
1260 if (sk->sk_destruct)
1261 (*sk->sk_destruct)(sk);
1263 /* We're finished with the socket */
1264 l2tp_tunnel_dec_refcount(tunnel);
1270 /* When the tunnel is closed, all the attached sessions need to go too.
1272 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1275 struct hlist_node *walk;
1276 struct hlist_node *tmp;
1277 struct l2tp_session *session;
1279 BUG_ON(tunnel == NULL);
1281 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1282 "%s: closing all sessions...\n", tunnel->name);
1284 write_lock_bh(&tunnel->hlist_lock);
1285 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1287 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1288 session = hlist_entry(walk, struct l2tp_session, hlist);
1290 PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO,
1291 "%s: closing session\n", session->name);
1293 hlist_del_init(&session->hlist);
1295 /* Since we should hold the sock lock while
1296 * doing any unbinding, we need to release the
1297 * lock we're holding before taking that lock.
1298 * Hold a reference to the sock so it doesn't
1299 * disappear as we're jumping between locks.
1301 if (session->ref != NULL)
1302 (*session->ref)(session);
1304 write_unlock_bh(&tunnel->hlist_lock);
1306 if (tunnel->version != L2TP_HDR_VER_2) {
1307 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1309 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1310 hlist_del_init_rcu(&session->global_hlist);
1311 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1315 if (session->session_close != NULL)
1316 (*session->session_close)(session);
1318 if (session->deref != NULL)
1319 (*session->deref)(session);
1321 write_lock_bh(&tunnel->hlist_lock);
1323 /* Now restart from the beginning of this hash
1324 * chain. We always remove a session from the
1325 * list so we are guaranteed to make forward
1331 write_unlock_bh(&tunnel->hlist_lock);
1334 /* Really kill the tunnel.
1335 * Come here only when all sessions have been cleared from the tunnel.
1337 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
1339 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1341 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1342 BUG_ON(tunnel->sock != NULL);
1344 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1345 "%s: free...\n", tunnel->name);
1347 /* Remove from tunnel list */
1348 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1349 list_del_rcu(&tunnel->list);
1350 kfree_rcu(tunnel, rcu);
1351 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1353 atomic_dec(&l2tp_tunnel_count);
1355 EXPORT_SYMBOL_GPL(l2tp_tunnel_free);
1357 /* Create a socket for the tunnel, if one isn't set up by
1358 * userspace. This is used for static tunnels where there is no
1359 * managing L2TP daemon.
1361 static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1364 struct sockaddr_in udp_addr;
1365 struct sockaddr_l2tpip ip_addr;
1366 struct socket *sock = NULL;
1368 switch (cfg->encap) {
1369 case L2TP_ENCAPTYPE_UDP:
1370 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1376 memset(&udp_addr, 0, sizeof(udp_addr));
1377 udp_addr.sin_family = AF_INET;
1378 udp_addr.sin_addr = cfg->local_ip;
1379 udp_addr.sin_port = htons(cfg->local_udp_port);
1380 err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr));
1384 udp_addr.sin_family = AF_INET;
1385 udp_addr.sin_addr = cfg->peer_ip;
1386 udp_addr.sin_port = htons(cfg->peer_udp_port);
1387 err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0);
1391 if (!cfg->use_udp_checksums)
1392 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1396 case L2TP_ENCAPTYPE_IP:
1397 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
1403 memset(&ip_addr, 0, sizeof(ip_addr));
1404 ip_addr.l2tp_family = AF_INET;
1405 ip_addr.l2tp_addr = cfg->local_ip;
1406 ip_addr.l2tp_conn_id = tunnel_id;
1407 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr));
1411 ip_addr.l2tp_family = AF_INET;
1412 ip_addr.l2tp_addr = cfg->peer_ip;
1413 ip_addr.l2tp_conn_id = peer_tunnel_id;
1414 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0);
1425 if ((err < 0) && sock) {
1433 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)
1435 struct l2tp_tunnel *tunnel = NULL;
1437 struct socket *sock = NULL;
1438 struct sock *sk = NULL;
1439 struct l2tp_net *pn;
1440 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1442 /* Get the tunnel socket from the fd, which was opened by
1443 * the userspace L2TP daemon. If not specified, create a
1447 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1452 sock = sockfd_lookup(fd, &err);
1454 printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1455 tunnel_id, fd, err);
1465 /* Quick sanity checks */
1467 case L2TP_ENCAPTYPE_UDP:
1468 err = -EPROTONOSUPPORT;
1469 if (sk->sk_protocol != IPPROTO_UDP) {
1470 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1471 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1475 case L2TP_ENCAPTYPE_IP:
1476 err = -EPROTONOSUPPORT;
1477 if (sk->sk_protocol != IPPROTO_L2TP) {
1478 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1479 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1485 /* Check if this socket has already been prepped */
1486 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1487 if (tunnel != NULL) {
1488 /* This socket has already been prepped */
1493 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1494 if (tunnel == NULL) {
1499 tunnel->version = version;
1500 tunnel->tunnel_id = tunnel_id;
1501 tunnel->peer_tunnel_id = peer_tunnel_id;
1502 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1504 tunnel->magic = L2TP_TUNNEL_MAGIC;
1505 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1506 rwlock_init(&tunnel->hlist_lock);
1508 /* The net we belong to */
1509 tunnel->l2tp_net = net;
1510 pn = l2tp_pernet(net);
1513 tunnel->debug = cfg->debug;
1515 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1516 tunnel->encap = encap;
1517 if (encap == L2TP_ENCAPTYPE_UDP) {
1518 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1519 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1520 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1523 sk->sk_user_data = tunnel;
1525 /* Hook on the tunnel socket destructor so that we can cleanup
1526 * if the tunnel socket goes away.
1528 tunnel->old_sk_destruct = sk->sk_destruct;
1529 sk->sk_destruct = &l2tp_tunnel_destruct;
1531 sk->sk_allocation = GFP_ATOMIC;
1533 /* Add tunnel to our list */
1534 INIT_LIST_HEAD(&tunnel->list);
1535 atomic_inc(&l2tp_tunnel_count);
1537 /* Bump the reference count. The tunnel context is deleted
1538 * only when this drops to zero. Must be done before list insertion
1540 l2tp_tunnel_inc_refcount(tunnel);
1541 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1542 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1543 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1550 /* If tunnel's socket was created by the kernel, it doesn't
1553 if (sock && sock->file)
1558 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1560 /* This function is used by the netlink TUNNEL_DELETE command.
1562 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1565 struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL;
1567 /* Force the tunnel socket to close. This will eventually
1568 * cause the tunnel to be deleted via the normal socket close
1569 * mechanisms when userspace closes the tunnel socket.
1572 err = inet_shutdown(sock, 2);
1574 /* If the tunnel's socket was created by the kernel,
1575 * close the socket here since the socket was not
1576 * created by userspace.
1578 if (sock->file == NULL)
1579 err = inet_release(sock);
1584 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1586 /* Really kill the session.
1588 void l2tp_session_free(struct l2tp_session *session)
1590 struct l2tp_tunnel *tunnel;
1592 BUG_ON(atomic_read(&session->ref_count) != 0);
1594 tunnel = session->tunnel;
1595 if (tunnel != NULL) {
1596 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1598 /* Delete the session from the hash */
1599 write_lock_bh(&tunnel->hlist_lock);
1600 hlist_del_init(&session->hlist);
1601 write_unlock_bh(&tunnel->hlist_lock);
1603 /* Unlink from the global hash if not L2TPv2 */
1604 if (tunnel->version != L2TP_HDR_VER_2) {
1605 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1607 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1608 hlist_del_init_rcu(&session->global_hlist);
1609 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1613 if (session->session_id != 0)
1614 atomic_dec(&l2tp_session_count);
1616 sock_put(tunnel->sock);
1618 /* This will delete the tunnel context if this
1619 * is the last session on the tunnel.
1621 session->tunnel = NULL;
1622 l2tp_tunnel_dec_refcount(tunnel);
1629 EXPORT_SYMBOL_GPL(l2tp_session_free);
1631 /* This function is used by the netlink SESSION_DELETE command and by
1634 int l2tp_session_delete(struct l2tp_session *session)
1636 if (session->session_close != NULL)
1637 (*session->session_close)(session);
1639 l2tp_session_dec_refcount(session);
1643 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1646 /* We come here whenever a session's send_seq, cookie_len or
1647 * l2specific_len parameters are set.
1649 static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1651 if (version == L2TP_HDR_VER_2) {
1652 session->hdr_len = 6;
1653 if (session->send_seq)
1654 session->hdr_len += 4;
1656 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1657 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1658 session->hdr_len += 4;
1663 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)
1665 struct l2tp_session *session;
1668 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1669 if (session != NULL) {
1670 session->magic = L2TP_SESSION_MAGIC;
1671 session->tunnel = tunnel;
1673 session->session_id = session_id;
1674 session->peer_session_id = peer_session_id;
1677 sprintf(&session->name[0], "sess %u/%u",
1678 tunnel->tunnel_id, session->session_id);
1680 skb_queue_head_init(&session->reorder_q);
1682 INIT_HLIST_NODE(&session->hlist);
1683 INIT_HLIST_NODE(&session->global_hlist);
1685 /* Inherit debug options from tunnel */
1686 session->debug = tunnel->debug;
1689 session->pwtype = cfg->pw_type;
1690 session->debug = cfg->debug;
1691 session->mtu = cfg->mtu;
1692 session->mru = cfg->mru;
1693 session->send_seq = cfg->send_seq;
1694 session->recv_seq = cfg->recv_seq;
1695 session->lns_mode = cfg->lns_mode;
1696 session->reorder_timeout = cfg->reorder_timeout;
1697 session->offset = cfg->offset;
1698 session->l2specific_type = cfg->l2specific_type;
1699 session->l2specific_len = cfg->l2specific_len;
1700 session->cookie_len = cfg->cookie_len;
1701 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1702 session->peer_cookie_len = cfg->peer_cookie_len;
1703 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1706 if (tunnel->version == L2TP_HDR_VER_2)
1707 session->build_header = l2tp_build_l2tpv2_header;
1709 session->build_header = l2tp_build_l2tpv3_header;
1711 l2tp_session_set_header_len(session, tunnel->version);
1713 l2tp_session_inc_refcount(session);
1715 err = l2tp_session_add_to_tunnel(tunnel, session);
1719 return ERR_PTR(err);
1722 l2tp_tunnel_inc_refcount(tunnel);
1724 /* Ensure tunnel socket isn't deleted */
1725 sock_hold(tunnel->sock);
1727 /* Ignore management session in session count value */
1728 if (session->session_id != 0)
1729 atomic_inc(&l2tp_session_count);
1734 return ERR_PTR(-ENOMEM);
1736 EXPORT_SYMBOL_GPL(l2tp_session_create);
1738 /*****************************************************************************
1740 *****************************************************************************/
1742 static __net_init int l2tp_init_net(struct net *net)
1744 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1747 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1748 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1750 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1751 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1753 spin_lock_init(&pn->l2tp_session_hlist_lock);
1758 static struct pernet_operations l2tp_net_ops = {
1759 .init = l2tp_init_net,
1761 .size = sizeof(struct l2tp_net),
1764 static int __init l2tp_init(void)
1768 rc = register_pernet_device(&l2tp_net_ops);
1772 printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION);
1778 static void __exit l2tp_exit(void)
1780 unregister_pernet_device(&l2tp_net_ops);
1783 module_init(l2tp_init);
1784 module_exit(l2tp_exit);
1786 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1787 MODULE_DESCRIPTION("L2TP core");
1788 MODULE_LICENSE("GPL");
1789 MODULE_VERSION(L2TP_DRV_VERSION);