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;
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);
383 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
385 write_unlock_bh(&tunnel->hlist_lock);
390 /* Lookup a tunnel by id
392 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
394 struct l2tp_tunnel *tunnel;
395 struct l2tp_net *pn = l2tp_pernet(net);
398 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
399 if (tunnel->tunnel_id == tunnel_id) {
400 rcu_read_unlock_bh();
404 rcu_read_unlock_bh();
408 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
410 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
412 struct l2tp_net *pn = l2tp_pernet(net);
413 struct l2tp_tunnel *tunnel;
417 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
419 rcu_read_unlock_bh();
424 rcu_read_unlock_bh();
428 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
430 /*****************************************************************************
431 * Receive data handling
432 *****************************************************************************/
434 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
437 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
439 struct sk_buff *skbp;
441 u32 ns = L2TP_SKB_CB(skb)->ns;
443 spin_lock_bh(&session->reorder_q.lock);
444 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
445 if (L2TP_SKB_CB(skbp)->ns > ns) {
446 __skb_queue_before(&session->reorder_q, skbp, skb);
447 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
448 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
449 session->name, ns, L2TP_SKB_CB(skbp)->ns,
450 skb_queue_len(&session->reorder_q));
451 session->stats.rx_oos_packets++;
456 __skb_queue_tail(&session->reorder_q, skb);
459 spin_unlock_bh(&session->reorder_q.lock);
462 /* Dequeue a single skb.
464 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
466 struct l2tp_tunnel *tunnel = session->tunnel;
467 int length = L2TP_SKB_CB(skb)->length;
469 /* We're about to requeue the skb, so return resources
470 * to its current owner (a socket receive buffer).
474 tunnel->stats.rx_packets++;
475 tunnel->stats.rx_bytes += length;
476 session->stats.rx_packets++;
477 session->stats.rx_bytes += length;
479 if (L2TP_SKB_CB(skb)->has_seq) {
482 if (tunnel->version == L2TP_HDR_VER_2)
483 session->nr &= 0xffff;
485 session->nr &= 0xffffff;
487 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
488 "%s: updated nr to %hu\n", session->name, session->nr);
491 /* call private receive handler */
492 if (session->recv_skb != NULL)
493 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
498 (*session->deref)(session);
501 /* Dequeue skbs from the session's reorder_q, subject to packet order.
502 * Skbs that have been in the queue for too long are simply discarded.
504 static void l2tp_recv_dequeue(struct l2tp_session *session)
509 /* If the pkt at the head of the queue has the nr that we
510 * expect to send up next, dequeue it and any other
511 * in-sequence packets behind it.
514 spin_lock_bh(&session->reorder_q.lock);
515 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
516 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
517 session->stats.rx_seq_discards++;
518 session->stats.rx_errors++;
519 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
520 "%s: oos pkt %u len %d discarded (too old), "
521 "waiting for %u, reorder_q_len=%d\n",
522 session->name, L2TP_SKB_CB(skb)->ns,
523 L2TP_SKB_CB(skb)->length, session->nr,
524 skb_queue_len(&session->reorder_q));
525 __skb_unlink(skb, &session->reorder_q);
528 (*session->deref)(session);
532 if (L2TP_SKB_CB(skb)->has_seq) {
533 if (L2TP_SKB_CB(skb)->ns != session->nr) {
534 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
535 "%s: holding oos pkt %u len %d, "
536 "waiting for %u, reorder_q_len=%d\n",
537 session->name, L2TP_SKB_CB(skb)->ns,
538 L2TP_SKB_CB(skb)->length, session->nr,
539 skb_queue_len(&session->reorder_q));
543 __skb_unlink(skb, &session->reorder_q);
545 /* Process the skb. We release the queue lock while we
546 * do so to let other contexts process the queue.
548 spin_unlock_bh(&session->reorder_q.lock);
549 l2tp_recv_dequeue_skb(session, skb);
554 spin_unlock_bh(&session->reorder_q.lock);
557 static inline int l2tp_verify_udp_checksum(struct sock *sk,
560 struct udphdr *uh = udp_hdr(skb);
561 u16 ulen = ntohs(uh->len);
562 struct inet_sock *inet;
565 if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
569 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
572 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
573 !csum_fold(csum_add(psum, skb->csum)))
578 return __skb_checksum_complete(skb);
581 /* Do receive processing of L2TP data frames. We handle both L2TPv2
582 * and L2TPv3 data frames here.
584 * L2TPv2 Data Message Header
587 * 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
588 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
589 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
590 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
591 * | Tunnel ID | Session ID |
592 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
593 * | Ns (opt) | Nr (opt) |
594 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
595 * | Offset Size (opt) | Offset pad... (opt)
596 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
598 * Data frames are marked by T=0. All other fields are the same as
599 * those in L2TP control frames.
601 * L2TPv3 Data Message Header
603 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
604 * | L2TP Session Header |
605 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
606 * | L2-Specific Sublayer |
607 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
608 * | Tunnel Payload ...
609 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
611 * L2TPv3 Session Header Over IP
614 * 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
615 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
617 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
618 * | Cookie (optional, maximum 64 bits)...
619 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
621 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
623 * L2TPv3 L2-Specific Sublayer Format
626 * 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
627 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
628 * |x|S|x|x|x|x|x|x| Sequence Number |
629 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
631 * Cookie value, sublayer format and offset (pad) are negotiated with
632 * the peer when the session is set up. Unlike L2TPv2, we do not need
633 * to parse the packet header to determine if optional fields are
636 * Caller must already have parsed the frame and determined that it is
637 * a data (not control) frame before coming here. Fields up to the
638 * session-id have already been parsed and ptr points to the data
639 * after the session-id.
641 * session->ref() must have been called prior to l2tp_recv_common().
642 * session->deref() will be called automatically after skb is processed.
644 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
645 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
646 int length, int (*payload_hook)(struct sk_buff *skb))
648 struct l2tp_tunnel *tunnel = session->tunnel;
652 /* Parse and check optional cookie */
653 if (session->peer_cookie_len > 0) {
654 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
655 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
656 "%s: cookie mismatch (%u/%u). Discarding.\n",
657 tunnel->name, tunnel->tunnel_id, session->session_id);
658 session->stats.rx_cookie_discards++;
661 ptr += session->peer_cookie_len;
664 /* Handle the optional sequence numbers. Sequence numbers are
665 * in different places for L2TPv2 and L2TPv3.
667 * If we are the LAC, enable/disable sequence numbers under
668 * the control of the LNS. If no sequence numbers present but
669 * we were expecting them, discard frame.
672 L2TP_SKB_CB(skb)->has_seq = 0;
673 if (tunnel->version == L2TP_HDR_VER_2) {
674 if (hdrflags & L2TP_HDRFLAG_S) {
675 ns = ntohs(*(__be16 *) ptr);
677 nr = ntohs(*(__be16 *) ptr);
680 /* Store L2TP info in the skb */
681 L2TP_SKB_CB(skb)->ns = ns;
682 L2TP_SKB_CB(skb)->has_seq = 1;
684 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
685 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
686 session->name, ns, nr, session->nr);
688 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
689 u32 l2h = ntohl(*(__be32 *) ptr);
691 if (l2h & 0x40000000) {
692 ns = l2h & 0x00ffffff;
694 /* Store L2TP info in the skb */
695 L2TP_SKB_CB(skb)->ns = ns;
696 L2TP_SKB_CB(skb)->has_seq = 1;
698 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
699 "%s: recv data ns=%u, session nr=%u\n",
700 session->name, ns, session->nr);
704 /* Advance past L2-specific header, if present */
705 ptr += session->l2specific_len;
707 if (L2TP_SKB_CB(skb)->has_seq) {
708 /* Received a packet with sequence numbers. If we're the LNS,
709 * check if we sre sending sequence numbers and if not,
712 if ((!session->lns_mode) && (!session->send_seq)) {
713 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
714 "%s: requested to enable seq numbers by LNS\n",
716 session->send_seq = -1;
717 l2tp_session_set_header_len(session, tunnel->version);
720 /* No sequence numbers.
721 * If user has configured mandatory sequence numbers, discard.
723 if (session->recv_seq) {
724 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
725 "%s: recv data has no seq numbers when required. "
726 "Discarding\n", session->name);
727 session->stats.rx_seq_discards++;
731 /* If we're the LAC and we're sending sequence numbers, the
732 * LNS has requested that we no longer send sequence numbers.
733 * If we're the LNS and we're sending sequence numbers, the
734 * LAC is broken. Discard the frame.
736 if ((!session->lns_mode) && (session->send_seq)) {
737 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
738 "%s: requested to disable seq numbers by LNS\n",
740 session->send_seq = 0;
741 l2tp_session_set_header_len(session, tunnel->version);
742 } else if (session->send_seq) {
743 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
744 "%s: recv data has no seq numbers when required. "
745 "Discarding\n", session->name);
746 session->stats.rx_seq_discards++;
751 /* Session data offset is handled differently for L2TPv2 and
752 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
753 * the header. For L2TPv3, the offset is negotiated using AVPs
754 * in the session setup control protocol.
756 if (tunnel->version == L2TP_HDR_VER_2) {
757 /* If offset bit set, skip it. */
758 if (hdrflags & L2TP_HDRFLAG_O) {
759 offset = ntohs(*(__be16 *)ptr);
763 ptr += session->offset;
766 if (!pskb_may_pull(skb, offset))
769 __skb_pull(skb, offset);
771 /* If caller wants to process the payload before we queue the
775 if ((*payload_hook)(skb))
778 /* Prepare skb for adding to the session's reorder_q. Hold
779 * packets for max reorder_timeout or 1 second if not
782 L2TP_SKB_CB(skb)->length = length;
783 L2TP_SKB_CB(skb)->expires = jiffies +
784 (session->reorder_timeout ? session->reorder_timeout : HZ);
786 /* Add packet to the session's receive queue. Reordering is done here, if
787 * enabled. Saved L2TP protocol info is stored in skb->sb[].
789 if (L2TP_SKB_CB(skb)->has_seq) {
790 if (session->reorder_timeout != 0) {
791 /* Packet reordering enabled. Add skb to session's
792 * reorder queue, in order of ns.
794 l2tp_recv_queue_skb(session, skb);
796 /* Packet reordering disabled. Discard out-of-sequence
799 if (L2TP_SKB_CB(skb)->ns != session->nr) {
800 session->stats.rx_seq_discards++;
801 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
802 "%s: oos pkt %u len %d discarded, "
803 "waiting for %u, reorder_q_len=%d\n",
804 session->name, L2TP_SKB_CB(skb)->ns,
805 L2TP_SKB_CB(skb)->length, session->nr,
806 skb_queue_len(&session->reorder_q));
809 skb_queue_tail(&session->reorder_q, skb);
812 /* No sequence numbers. Add the skb to the tail of the
813 * reorder queue. This ensures that it will be
814 * delivered after all previous sequenced skbs.
816 skb_queue_tail(&session->reorder_q, skb);
819 /* Try to dequeue as many skbs from reorder_q as we can. */
820 l2tp_recv_dequeue(session);
825 session->stats.rx_errors++;
829 (*session->deref)(session);
831 EXPORT_SYMBOL(l2tp_recv_common);
833 /* Drop skbs from the session's reorder_q
835 int l2tp_session_queue_purge(struct l2tp_session *session)
837 struct sk_buff *skb = NULL;
839 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
840 while ((skb = skb_dequeue(&session->reorder_q))) {
841 session->stats.rx_errors++;
844 (*session->deref)(session);
848 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge);
850 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
851 * here. The skb is not on a list when we get here.
852 * Returns 0 if the packet was a data packet and was successfully passed on.
853 * Returns 1 if the packet was not a good data packet and could not be
854 * forwarded. All such packets are passed up to userspace to deal with.
856 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
857 int (*payload_hook)(struct sk_buff *skb))
859 struct l2tp_session *session = NULL;
860 unsigned char *ptr, *optr;
862 u32 tunnel_id, session_id;
867 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
868 goto discard_bad_csum;
870 /* UDP always verifies the packet length. */
871 __skb_pull(skb, sizeof(struct udphdr));
874 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
875 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
876 "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
880 /* Trace packet contents, if enabled */
881 if (tunnel->debug & L2TP_MSG_DATA) {
882 length = min(32u, skb->len);
883 if (!pskb_may_pull(skb, length))
886 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
890 printk(" %02X", skb->data[offset]);
891 } while (++offset < length);
896 /* Point to L2TP header */
897 optr = ptr = skb->data;
899 /* Get L2TP header flags */
900 hdrflags = ntohs(*(__be16 *) ptr);
902 /* Check protocol version */
903 version = hdrflags & L2TP_HDR_VER_MASK;
904 if (version != tunnel->version) {
905 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
906 "%s: recv protocol version mismatch: got %d expected %d\n",
907 tunnel->name, version, tunnel->version);
911 /* Get length of L2TP packet */
914 /* If type is control packet, it is handled by userspace. */
915 if (hdrflags & L2TP_HDRFLAG_T) {
916 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
917 "%s: recv control packet, len=%d\n", tunnel->name, length);
924 if (tunnel->version == L2TP_HDR_VER_2) {
925 /* If length is present, skip it */
926 if (hdrflags & L2TP_HDRFLAG_L)
929 /* Extract tunnel and session ID */
930 tunnel_id = ntohs(*(__be16 *) ptr);
932 session_id = ntohs(*(__be16 *) ptr);
935 ptr += 2; /* skip reserved bits */
936 tunnel_id = tunnel->tunnel_id;
937 session_id = ntohl(*(__be32 *) ptr);
941 /* Find the session context */
942 session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id, true);
943 if (!session || !session->recv_skb) {
946 session->deref(session);
947 l2tp_session_dec_refcount(session);
950 /* Not found? Pass to userspace to deal with */
951 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
952 "%s: no session found (%u/%u). Passing up.\n",
953 tunnel->name, tunnel_id, session_id);
957 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
958 l2tp_session_dec_refcount(session);
963 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
964 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
965 tunnel->stats.rx_errors++;
971 /* Put UDP header back */
972 __skb_push(skb, sizeof(struct udphdr));
977 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
981 * >0: skb should be passed up to userspace as UDP.
983 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
985 struct l2tp_tunnel *tunnel;
987 tunnel = l2tp_sock_to_tunnel(sk);
991 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
992 "%s: received %d bytes\n", tunnel->name, skb->len);
994 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
1005 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
1007 /************************************************************************
1009 ***********************************************************************/
1011 /* Build an L2TP header for the session into the buffer provided.
1013 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
1015 struct l2tp_tunnel *tunnel = session->tunnel;
1018 u16 flags = L2TP_HDR_VER_2;
1019 u32 tunnel_id = tunnel->peer_tunnel_id;
1020 u32 session_id = session->peer_session_id;
1022 if (session->send_seq)
1023 flags |= L2TP_HDRFLAG_S;
1025 /* Setup L2TP header. */
1026 *bufp++ = htons(flags);
1027 *bufp++ = htons(tunnel_id);
1028 *bufp++ = htons(session_id);
1029 if (session->send_seq) {
1030 *bufp++ = htons(session->ns);
1033 session->ns &= 0xffff;
1034 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
1035 "%s: updated ns to %u\n", session->name, session->ns);
1041 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
1043 struct l2tp_tunnel *tunnel = session->tunnel;
1047 /* Setup L2TP header. The header differs slightly for UDP and
1048 * IP encapsulations. For UDP, there is 4 bytes of flags.
1050 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1051 u16 flags = L2TP_HDR_VER_3;
1052 *((__be16 *) bufp) = htons(flags);
1054 *((__be16 *) bufp) = 0;
1058 *((__be32 *) bufp) = htonl(session->peer_session_id);
1060 if (session->cookie_len) {
1061 memcpy(bufp, &session->cookie[0], session->cookie_len);
1062 bufp += session->cookie_len;
1064 if (session->l2specific_len) {
1065 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
1067 if (session->send_seq) {
1068 l2h = 0x40000000 | session->ns;
1070 session->ns &= 0xffffff;
1071 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
1072 "%s: updated ns to %u\n", session->name, session->ns);
1075 *((__be32 *) bufp) = htonl(l2h);
1077 bufp += session->l2specific_len;
1079 if (session->offset)
1080 bufp += session->offset;
1085 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1086 struct flowi *fl, size_t data_len)
1088 struct l2tp_tunnel *tunnel = session->tunnel;
1089 unsigned int len = skb->len;
1093 if (session->send_seq)
1094 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
1095 "%s: send %Zd bytes, ns=%u\n", session->name,
1096 data_len, session->ns - 1);
1098 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
1099 "%s: send %Zd bytes\n", session->name, data_len);
1101 if (session->debug & L2TP_MSG_DATA) {
1103 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1104 unsigned char *datap = skb->data + uhlen;
1106 printk(KERN_DEBUG "%s: xmit:", session->name);
1107 for (i = 0; i < (len - uhlen); i++) {
1108 printk(" %02X", *datap++);
1117 /* Queue the packet to IP for output */
1119 error = ip_queue_xmit(skb, fl);
1123 tunnel->stats.tx_packets++;
1124 tunnel->stats.tx_bytes += len;
1125 session->stats.tx_packets++;
1126 session->stats.tx_bytes += len;
1128 tunnel->stats.tx_errors++;
1129 session->stats.tx_errors++;
1135 /* Automatically called when the skb is freed.
1137 static void l2tp_sock_wfree(struct sk_buff *skb)
1142 /* For data skbs that we transmit, we associate with the tunnel socket
1143 * but don't do accounting.
1145 static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1149 skb->destructor = l2tp_sock_wfree;
1152 /* If caller requires the skb to have a ppp header, the header must be
1153 * inserted in the skb data before calling this function.
1155 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1157 int data_len = skb->len;
1158 struct l2tp_tunnel *tunnel = session->tunnel;
1159 struct sock *sk = tunnel->sock;
1162 struct inet_sock *inet;
1167 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1170 /* Check that there's enough headroom in the skb to insert IP,
1171 * UDP and L2TP headers. If not enough, expand it to
1172 * make room. Adjust truesize.
1174 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1176 old_headroom = skb_headroom(skb);
1177 if (skb_cow_head(skb, headroom)) {
1182 new_headroom = skb_headroom(skb);
1184 skb->truesize += new_headroom - old_headroom;
1186 /* Setup L2TP header */
1187 session->build_header(session, __skb_push(skb, hdr_len));
1189 /* Reset skb netfilter state */
1190 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1191 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1196 if (sock_owned_by_user(sk)) {
1201 /* Get routing info from the tunnel socket */
1203 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
1206 fl = &inet->cork.fl;
1207 switch (tunnel->encap) {
1208 case L2TP_ENCAPTYPE_UDP:
1209 /* Setup UDP header */
1210 __skb_push(skb, sizeof(*uh));
1211 skb_reset_transport_header(skb);
1213 uh->source = inet->inet_sport;
1214 uh->dest = inet->inet_dport;
1215 udp_len = uhlen + hdr_len + data_len;
1216 uh->len = htons(udp_len);
1219 /* Calculate UDP checksum if configured to do so */
1220 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1221 skb->ip_summed = CHECKSUM_NONE;
1222 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1223 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1224 skb->ip_summed = CHECKSUM_COMPLETE;
1225 csum = skb_checksum(skb, 0, udp_len, 0);
1226 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1228 udp_len, IPPROTO_UDP, csum);
1230 uh->check = CSUM_MANGLED_0;
1232 skb->ip_summed = CHECKSUM_PARTIAL;
1233 skb->csum_start = skb_transport_header(skb) - skb->head;
1234 skb->csum_offset = offsetof(struct udphdr, check);
1235 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1237 udp_len, IPPROTO_UDP, 0);
1241 case L2TP_ENCAPTYPE_IP:
1245 l2tp_skb_set_owner_w(skb, sk);
1247 l2tp_xmit_core(session, skb, fl, data_len);
1254 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1256 /*****************************************************************************
1257 * Tinnel and session create/destroy.
1258 *****************************************************************************/
1260 /* Tunnel socket destruct hook.
1261 * The tunnel context is deleted only when all session sockets have been
1264 static void l2tp_tunnel_destruct(struct sock *sk)
1266 struct l2tp_tunnel *tunnel;
1268 tunnel = sk->sk_user_data;
1272 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1273 "%s: closing...\n", tunnel->name);
1275 /* Close all sessions */
1276 l2tp_tunnel_closeall(tunnel);
1278 switch (tunnel->encap) {
1279 case L2TP_ENCAPTYPE_UDP:
1280 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1281 (udp_sk(sk))->encap_type = 0;
1282 (udp_sk(sk))->encap_rcv = NULL;
1284 case L2TP_ENCAPTYPE_IP:
1288 /* Remove hooks into tunnel socket */
1289 tunnel->sock = NULL;
1290 sk->sk_destruct = tunnel->old_sk_destruct;
1291 sk->sk_user_data = NULL;
1293 /* Call the original destructor */
1294 if (sk->sk_destruct)
1295 (*sk->sk_destruct)(sk);
1297 /* We're finished with the socket */
1298 l2tp_tunnel_dec_refcount(tunnel);
1304 /* When the tunnel is closed, all the attached sessions need to go too.
1306 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1309 struct hlist_node *walk;
1310 struct hlist_node *tmp;
1311 struct l2tp_session *session;
1313 BUG_ON(tunnel == NULL);
1315 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1316 "%s: closing all sessions...\n", tunnel->name);
1318 write_lock_bh(&tunnel->hlist_lock);
1319 tunnel->acpt_newsess = false;
1320 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1322 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1323 session = hlist_entry(walk, struct l2tp_session, hlist);
1325 PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO,
1326 "%s: closing session\n", session->name);
1328 hlist_del_init(&session->hlist);
1330 /* Since we should hold the sock lock while
1331 * doing any unbinding, we need to release the
1332 * lock we're holding before taking that lock.
1333 * Hold a reference to the sock so it doesn't
1334 * disappear as we're jumping between locks.
1336 if (session->ref != NULL)
1337 (*session->ref)(session);
1339 write_unlock_bh(&tunnel->hlist_lock);
1341 if (tunnel->version != L2TP_HDR_VER_2) {
1342 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1344 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1345 hlist_del_init_rcu(&session->global_hlist);
1346 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1350 l2tp_session_queue_purge(session);
1352 if (session->session_close != NULL)
1353 (*session->session_close)(session);
1355 if (session->deref != NULL)
1356 (*session->deref)(session);
1358 write_lock_bh(&tunnel->hlist_lock);
1360 /* Now restart from the beginning of this hash
1361 * chain. We always remove a session from the
1362 * list so we are guaranteed to make forward
1368 write_unlock_bh(&tunnel->hlist_lock);
1371 /* Really kill the tunnel.
1372 * Come here only when all sessions have been cleared from the tunnel.
1374 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
1376 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1378 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1379 BUG_ON(tunnel->sock != NULL);
1381 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1382 "%s: free...\n", tunnel->name);
1384 /* Remove from tunnel list */
1385 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1386 list_del_rcu(&tunnel->list);
1387 kfree_rcu(tunnel, rcu);
1388 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1390 atomic_dec(&l2tp_tunnel_count);
1392 EXPORT_SYMBOL_GPL(l2tp_tunnel_free);
1394 /* Create a socket for the tunnel, if one isn't set up by
1395 * userspace. This is used for static tunnels where there is no
1396 * managing L2TP daemon.
1398 static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1401 struct sockaddr_in udp_addr;
1402 struct sockaddr_l2tpip ip_addr;
1403 struct socket *sock = NULL;
1405 switch (cfg->encap) {
1406 case L2TP_ENCAPTYPE_UDP:
1407 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1413 memset(&udp_addr, 0, sizeof(udp_addr));
1414 udp_addr.sin_family = AF_INET;
1415 udp_addr.sin_addr = cfg->local_ip;
1416 udp_addr.sin_port = htons(cfg->local_udp_port);
1417 err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr));
1421 udp_addr.sin_family = AF_INET;
1422 udp_addr.sin_addr = cfg->peer_ip;
1423 udp_addr.sin_port = htons(cfg->peer_udp_port);
1424 err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0);
1428 if (!cfg->use_udp_checksums)
1429 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1433 case L2TP_ENCAPTYPE_IP:
1434 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
1440 memset(&ip_addr, 0, sizeof(ip_addr));
1441 ip_addr.l2tp_family = AF_INET;
1442 ip_addr.l2tp_addr = cfg->local_ip;
1443 ip_addr.l2tp_conn_id = tunnel_id;
1444 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr));
1448 ip_addr.l2tp_family = AF_INET;
1449 ip_addr.l2tp_addr = cfg->peer_ip;
1450 ip_addr.l2tp_conn_id = peer_tunnel_id;
1451 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0);
1462 if ((err < 0) && sock) {
1470 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)
1472 struct l2tp_tunnel *tunnel = NULL;
1474 struct socket *sock = NULL;
1475 struct sock *sk = NULL;
1476 struct l2tp_net *pn;
1477 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1479 /* Get the tunnel socket from the fd, which was opened by
1480 * the userspace L2TP daemon. If not specified, create a
1484 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1489 sock = sockfd_lookup(fd, &err);
1491 printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1492 tunnel_id, fd, err);
1502 /* Quick sanity checks */
1504 case L2TP_ENCAPTYPE_UDP:
1505 err = -EPROTONOSUPPORT;
1506 if (sk->sk_protocol != IPPROTO_UDP) {
1507 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1508 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1512 case L2TP_ENCAPTYPE_IP:
1513 err = -EPROTONOSUPPORT;
1514 if (sk->sk_protocol != IPPROTO_L2TP) {
1515 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1516 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1522 /* Check if this socket has already been prepped */
1523 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1524 if (tunnel != NULL) {
1525 /* This socket has already been prepped */
1530 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1531 if (tunnel == NULL) {
1536 tunnel->version = version;
1537 tunnel->tunnel_id = tunnel_id;
1538 tunnel->peer_tunnel_id = peer_tunnel_id;
1539 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1541 tunnel->magic = L2TP_TUNNEL_MAGIC;
1542 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1543 rwlock_init(&tunnel->hlist_lock);
1544 tunnel->acpt_newsess = true;
1546 /* The net we belong to */
1547 tunnel->l2tp_net = net;
1548 pn = l2tp_pernet(net);
1551 tunnel->debug = cfg->debug;
1553 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1554 tunnel->encap = encap;
1555 if (encap == L2TP_ENCAPTYPE_UDP) {
1556 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1557 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1558 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1561 sk->sk_user_data = tunnel;
1563 /* Hook on the tunnel socket destructor so that we can cleanup
1564 * if the tunnel socket goes away.
1566 tunnel->old_sk_destruct = sk->sk_destruct;
1567 sk->sk_destruct = &l2tp_tunnel_destruct;
1569 sk->sk_allocation = GFP_ATOMIC;
1571 /* Add tunnel to our list */
1572 INIT_LIST_HEAD(&tunnel->list);
1573 atomic_inc(&l2tp_tunnel_count);
1575 /* Bump the reference count. The tunnel context is deleted
1576 * only when this drops to zero. Must be done before list insertion
1578 l2tp_tunnel_inc_refcount(tunnel);
1579 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1580 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1581 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1588 /* If tunnel's socket was created by the kernel, it doesn't
1591 if (sock && sock->file)
1596 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1598 /* This function is used by the netlink TUNNEL_DELETE command.
1600 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1603 struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL;
1605 /* Force the tunnel socket to close. This will eventually
1606 * cause the tunnel to be deleted via the normal socket close
1607 * mechanisms when userspace closes the tunnel socket.
1610 err = inet_shutdown(sock, 2);
1612 /* If the tunnel's socket was created by the kernel,
1613 * close the socket here since the socket was not
1614 * created by userspace.
1616 if (sock->file == NULL)
1617 err = inet_release(sock);
1622 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1624 /* Really kill the session.
1626 void l2tp_session_free(struct l2tp_session *session)
1628 struct l2tp_tunnel *tunnel;
1630 BUG_ON(atomic_read(&session->ref_count) != 0);
1632 tunnel = session->tunnel;
1633 if (tunnel != NULL) {
1634 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1636 /* Delete the session from the hash */
1637 write_lock_bh(&tunnel->hlist_lock);
1638 hlist_del_init(&session->hlist);
1639 write_unlock_bh(&tunnel->hlist_lock);
1641 /* Unlink from the global hash if not L2TPv2 */
1642 if (tunnel->version != L2TP_HDR_VER_2) {
1643 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1645 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1646 hlist_del_init_rcu(&session->global_hlist);
1647 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1651 if (session->session_id != 0)
1652 atomic_dec(&l2tp_session_count);
1654 sock_put(tunnel->sock);
1656 /* This will delete the tunnel context if this
1657 * is the last session on the tunnel.
1659 session->tunnel = NULL;
1660 l2tp_tunnel_dec_refcount(tunnel);
1667 EXPORT_SYMBOL_GPL(l2tp_session_free);
1669 /* This function is used by the netlink SESSION_DELETE command and by
1672 int l2tp_session_delete(struct l2tp_session *session)
1674 l2tp_session_queue_purge(session);
1676 if (session->session_close != NULL)
1677 (*session->session_close)(session);
1679 l2tp_session_dec_refcount(session);
1683 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1686 /* We come here whenever a session's send_seq, cookie_len or
1687 * l2specific_len parameters are set.
1689 static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1691 if (version == L2TP_HDR_VER_2) {
1692 session->hdr_len = 6;
1693 if (session->send_seq)
1694 session->hdr_len += 4;
1696 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1697 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1698 session->hdr_len += 4;
1703 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)
1705 struct l2tp_session *session;
1708 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1709 if (session != NULL) {
1710 session->magic = L2TP_SESSION_MAGIC;
1711 session->tunnel = tunnel;
1713 session->session_id = session_id;
1714 session->peer_session_id = peer_session_id;
1717 sprintf(&session->name[0], "sess %u/%u",
1718 tunnel->tunnel_id, session->session_id);
1720 skb_queue_head_init(&session->reorder_q);
1722 INIT_HLIST_NODE(&session->hlist);
1723 INIT_HLIST_NODE(&session->global_hlist);
1725 /* Inherit debug options from tunnel */
1726 session->debug = tunnel->debug;
1729 session->pwtype = cfg->pw_type;
1730 session->debug = cfg->debug;
1731 session->mtu = cfg->mtu;
1732 session->mru = cfg->mru;
1733 session->send_seq = cfg->send_seq;
1734 session->recv_seq = cfg->recv_seq;
1735 session->lns_mode = cfg->lns_mode;
1736 session->reorder_timeout = cfg->reorder_timeout;
1737 session->offset = cfg->offset;
1738 session->l2specific_type = cfg->l2specific_type;
1739 session->l2specific_len = cfg->l2specific_len;
1740 session->cookie_len = cfg->cookie_len;
1741 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1742 session->peer_cookie_len = cfg->peer_cookie_len;
1743 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1746 if (tunnel->version == L2TP_HDR_VER_2)
1747 session->build_header = l2tp_build_l2tpv2_header;
1749 session->build_header = l2tp_build_l2tpv3_header;
1751 l2tp_session_set_header_len(session, tunnel->version);
1753 l2tp_session_inc_refcount(session);
1755 err = l2tp_session_add_to_tunnel(tunnel, session);
1759 return ERR_PTR(err);
1762 /* Ignore management session in session count value */
1763 if (session->session_id != 0)
1764 atomic_inc(&l2tp_session_count);
1769 return ERR_PTR(-ENOMEM);
1771 EXPORT_SYMBOL_GPL(l2tp_session_create);
1773 /*****************************************************************************
1775 *****************************************************************************/
1777 static __net_init int l2tp_init_net(struct net *net)
1779 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1782 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1783 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1785 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1786 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1788 spin_lock_init(&pn->l2tp_session_hlist_lock);
1793 static struct pernet_operations l2tp_net_ops = {
1794 .init = l2tp_init_net,
1796 .size = sizeof(struct l2tp_net),
1799 static int __init l2tp_init(void)
1803 rc = register_pernet_device(&l2tp_net_ops);
1807 printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION);
1813 static void __exit l2tp_exit(void)
1815 unregister_pernet_device(&l2tp_net_ops);
1818 module_init(l2tp_init);
1819 module_exit(l2tp_exit);
1821 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1822 MODULE_DESCRIPTION("L2TP core");
1823 MODULE_LICENSE("GPL");
1824 MODULE_VERSION(L2TP_DRV_VERSION);