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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/module.h>
24 #include <linux/string.h>
25 #include <linux/list.h>
26 #include <linux/rculist.h>
27 #include <linux/uaccess.h>
29 #include <linux/kernel.h>
30 #include <linux/spinlock.h>
31 #include <linux/kthread.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 #include <linux/errno.h>
35 #include <linux/jiffies.h>
37 #include <linux/netdevice.h>
38 #include <linux/net.h>
39 #include <linux/inetdevice.h>
40 #include <linux/skbuff.h>
41 #include <linux/init.h>
44 #include <linux/udp.h>
45 #include <linux/l2tp.h>
46 #include <linux/hash.h>
47 #include <linux/sort.h>
48 #include <linux/file.h>
49 #include <linux/nsproxy.h>
50 #include <net/net_namespace.h>
51 #include <net/netns/generic.h>
55 #include <net/udp_tunnel.h>
56 #include <net/inet_common.h>
58 #include <net/protocol.h>
59 #include <net/inet6_connection_sock.h>
60 #include <net/inet_ecn.h>
61 #include <net/ip6_route.h>
62 #include <net/ip6_checksum.h>
64 #include <asm/byteorder.h>
65 #include <linux/atomic.h>
67 #include "l2tp_core.h"
69 #define L2TP_DRV_VERSION "V2.0"
71 /* L2TP header constants */
72 #define L2TP_HDRFLAG_T 0x8000
73 #define L2TP_HDRFLAG_L 0x4000
74 #define L2TP_HDRFLAG_S 0x0800
75 #define L2TP_HDRFLAG_O 0x0200
76 #define L2TP_HDRFLAG_P 0x0100
78 #define L2TP_HDR_VER_MASK 0x000F
79 #define L2TP_HDR_VER_2 0x0002
80 #define L2TP_HDR_VER_3 0x0003
82 /* L2TPv3 default L2-specific sublayer */
83 #define L2TP_SLFLAG_S 0x40000000
84 #define L2TP_SL_SEQ_MASK 0x00ffffff
86 #define L2TP_HDR_SIZE_SEQ 10
87 #define L2TP_HDR_SIZE_NOSEQ 6
89 /* Default trace flags */
90 #define L2TP_DEFAULT_DEBUG_FLAGS 0
92 /* Private data stored for received packets in the skb.
98 unsigned long expires;
101 #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
103 static struct workqueue_struct *l2tp_wq;
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 #if IS_ENABLED(CONFIG_IPV6)
115 static bool l2tp_sk_is_v6(struct sock *sk)
117 return sk->sk_family == PF_INET6 &&
118 !ipv6_addr_v4mapped(&sk->sk_v6_daddr);
122 static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk)
124 return sk->sk_user_data;
127 static inline struct l2tp_net *l2tp_pernet(const struct net *net)
131 return net_generic(net, l2tp_net_id);
134 /* Session hash global list for L2TPv3.
135 * The session_id SHOULD be random according to RFC3931, but several
136 * L2TP implementations use incrementing session_ids. So we do a real
137 * hash on the session_id, rather than a simple bitmask.
139 static inline struct hlist_head *
140 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
142 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
146 /* Session hash list.
147 * The session_id SHOULD be random according to RFC2661, but several
148 * L2TP implementations (Cisco and Microsoft) use incrementing
149 * session_ids. So we do a real hash on the session_id, rather than a
152 static inline struct hlist_head *
153 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
155 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
158 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
160 sock_put(tunnel->sock);
161 /* the tunnel is freed in the socket destructor */
163 EXPORT_SYMBOL(l2tp_tunnel_free);
165 /* Lookup a tunnel. A new reference is held on the returned tunnel. */
166 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id)
168 const struct l2tp_net *pn = l2tp_pernet(net);
169 struct l2tp_tunnel *tunnel;
172 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
173 if (tunnel->tunnel_id == tunnel_id) {
174 l2tp_tunnel_inc_refcount(tunnel);
175 rcu_read_unlock_bh();
180 rcu_read_unlock_bh();
184 EXPORT_SYMBOL_GPL(l2tp_tunnel_get);
186 /* Lookup a session. A new reference is held on the returned session. */
187 struct l2tp_session *l2tp_session_get(const struct net *net,
188 struct l2tp_tunnel *tunnel,
191 struct hlist_head *session_list;
192 struct l2tp_session *session;
195 struct l2tp_net *pn = l2tp_pernet(net);
197 session_list = l2tp_session_id_hash_2(pn, session_id);
200 hlist_for_each_entry_rcu(session, session_list, global_hlist) {
201 if (session->session_id == session_id) {
202 l2tp_session_inc_refcount(session);
203 rcu_read_unlock_bh();
208 rcu_read_unlock_bh();
213 session_list = l2tp_session_id_hash(tunnel, session_id);
214 read_lock_bh(&tunnel->hlist_lock);
215 hlist_for_each_entry(session, session_list, hlist) {
216 if (session->session_id == session_id) {
217 l2tp_session_inc_refcount(session);
218 read_unlock_bh(&tunnel->hlist_lock);
223 read_unlock_bh(&tunnel->hlist_lock);
227 EXPORT_SYMBOL_GPL(l2tp_session_get);
229 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth)
232 struct l2tp_session *session;
235 read_lock_bh(&tunnel->hlist_lock);
236 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
237 hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) {
239 l2tp_session_inc_refcount(session);
240 read_unlock_bh(&tunnel->hlist_lock);
246 read_unlock_bh(&tunnel->hlist_lock);
250 EXPORT_SYMBOL_GPL(l2tp_session_get_nth);
252 /* Lookup a session by interface name.
253 * This is very inefficient but is only used by management interfaces.
255 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
258 struct l2tp_net *pn = l2tp_pernet(net);
260 struct l2tp_session *session;
263 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
264 hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) {
265 if (!strcmp(session->ifname, ifname)) {
266 l2tp_session_inc_refcount(session);
267 rcu_read_unlock_bh();
274 rcu_read_unlock_bh();
278 EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname);
280 int l2tp_session_register(struct l2tp_session *session,
281 struct l2tp_tunnel *tunnel)
283 struct l2tp_session *session_walk;
284 struct hlist_head *g_head;
285 struct hlist_head *head;
289 head = l2tp_session_id_hash(tunnel, session->session_id);
291 write_lock_bh(&tunnel->hlist_lock);
292 if (!tunnel->acpt_newsess) {
297 hlist_for_each_entry(session_walk, head, hlist)
298 if (session_walk->session_id == session->session_id) {
303 if (tunnel->version == L2TP_HDR_VER_3) {
304 pn = l2tp_pernet(tunnel->l2tp_net);
305 g_head = l2tp_session_id_hash_2(l2tp_pernet(tunnel->l2tp_net),
306 session->session_id);
308 spin_lock_bh(&pn->l2tp_session_hlist_lock);
310 hlist_for_each_entry(session_walk, g_head, global_hlist)
311 if (session_walk->session_id == session->session_id) {
313 goto err_tlock_pnlock;
316 l2tp_tunnel_inc_refcount(tunnel);
317 hlist_add_head_rcu(&session->global_hlist, g_head);
319 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
321 l2tp_tunnel_inc_refcount(tunnel);
324 hlist_add_head(&session->hlist, head);
325 write_unlock_bh(&tunnel->hlist_lock);
330 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
332 write_unlock_bh(&tunnel->hlist_lock);
336 EXPORT_SYMBOL_GPL(l2tp_session_register);
338 /* Lookup a tunnel by id
340 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id)
342 struct l2tp_tunnel *tunnel;
343 struct l2tp_net *pn = l2tp_pernet(net);
346 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
347 if (tunnel->tunnel_id == tunnel_id) {
348 rcu_read_unlock_bh();
352 rcu_read_unlock_bh();
356 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
358 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth)
360 struct l2tp_net *pn = l2tp_pernet(net);
361 struct l2tp_tunnel *tunnel;
365 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
367 rcu_read_unlock_bh();
372 rcu_read_unlock_bh();
376 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
378 /*****************************************************************************
379 * Receive data handling
380 *****************************************************************************/
382 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
385 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
387 struct sk_buff *skbp;
389 u32 ns = L2TP_SKB_CB(skb)->ns;
391 spin_lock_bh(&session->reorder_q.lock);
392 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
393 if (L2TP_SKB_CB(skbp)->ns > ns) {
394 __skb_queue_before(&session->reorder_q, skbp, skb);
395 l2tp_dbg(session, L2TP_MSG_SEQ,
396 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
397 session->name, ns, L2TP_SKB_CB(skbp)->ns,
398 skb_queue_len(&session->reorder_q));
399 atomic_long_inc(&session->stats.rx_oos_packets);
404 __skb_queue_tail(&session->reorder_q, skb);
407 spin_unlock_bh(&session->reorder_q.lock);
410 /* Dequeue a single skb.
412 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
414 struct l2tp_tunnel *tunnel = session->tunnel;
415 int length = L2TP_SKB_CB(skb)->length;
417 /* We're about to requeue the skb, so return resources
418 * to its current owner (a socket receive buffer).
422 atomic_long_inc(&tunnel->stats.rx_packets);
423 atomic_long_add(length, &tunnel->stats.rx_bytes);
424 atomic_long_inc(&session->stats.rx_packets);
425 atomic_long_add(length, &session->stats.rx_bytes);
427 if (L2TP_SKB_CB(skb)->has_seq) {
430 session->nr &= session->nr_max;
432 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
433 session->name, session->nr);
436 /* call private receive handler */
437 if (session->recv_skb != NULL)
438 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
443 /* Dequeue skbs from the session's reorder_q, subject to packet order.
444 * Skbs that have been in the queue for too long are simply discarded.
446 static void l2tp_recv_dequeue(struct l2tp_session *session)
451 /* If the pkt at the head of the queue has the nr that we
452 * expect to send up next, dequeue it and any other
453 * in-sequence packets behind it.
456 spin_lock_bh(&session->reorder_q.lock);
457 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
458 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
459 atomic_long_inc(&session->stats.rx_seq_discards);
460 atomic_long_inc(&session->stats.rx_errors);
461 l2tp_dbg(session, L2TP_MSG_SEQ,
462 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
463 session->name, L2TP_SKB_CB(skb)->ns,
464 L2TP_SKB_CB(skb)->length, session->nr,
465 skb_queue_len(&session->reorder_q));
466 session->reorder_skip = 1;
467 __skb_unlink(skb, &session->reorder_q);
472 if (L2TP_SKB_CB(skb)->has_seq) {
473 if (session->reorder_skip) {
474 l2tp_dbg(session, L2TP_MSG_SEQ,
475 "%s: advancing nr to next pkt: %u -> %u",
476 session->name, session->nr,
477 L2TP_SKB_CB(skb)->ns);
478 session->reorder_skip = 0;
479 session->nr = L2TP_SKB_CB(skb)->ns;
481 if (L2TP_SKB_CB(skb)->ns != session->nr) {
482 l2tp_dbg(session, L2TP_MSG_SEQ,
483 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
484 session->name, L2TP_SKB_CB(skb)->ns,
485 L2TP_SKB_CB(skb)->length, session->nr,
486 skb_queue_len(&session->reorder_q));
490 __skb_unlink(skb, &session->reorder_q);
492 /* Process the skb. We release the queue lock while we
493 * do so to let other contexts process the queue.
495 spin_unlock_bh(&session->reorder_q.lock);
496 l2tp_recv_dequeue_skb(session, skb);
501 spin_unlock_bh(&session->reorder_q.lock);
504 static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
508 if (nr >= session->nr)
509 nws = nr - session->nr;
511 nws = (session->nr_max + 1) - (session->nr - nr);
513 return nws < session->nr_window_size;
516 /* If packet has sequence numbers, queue it if acceptable. Returns 0 if
517 * acceptable, else non-zero.
519 static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb)
521 if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) {
522 /* Packet sequence number is outside allowed window.
525 l2tp_dbg(session, L2TP_MSG_SEQ,
526 "%s: pkt %u len %d discarded, outside window, nr=%u\n",
527 session->name, L2TP_SKB_CB(skb)->ns,
528 L2TP_SKB_CB(skb)->length, session->nr);
532 if (session->reorder_timeout != 0) {
533 /* Packet reordering enabled. Add skb to session's
534 * reorder queue, in order of ns.
536 l2tp_recv_queue_skb(session, skb);
540 /* Packet reordering disabled. Discard out-of-sequence packets, while
541 * tracking the number if in-sequence packets after the first OOS packet
542 * is seen. After nr_oos_count_max in-sequence packets, reset the
543 * sequence number to re-enable packet reception.
545 if (L2TP_SKB_CB(skb)->ns == session->nr) {
546 skb_queue_tail(&session->reorder_q, skb);
548 u32 nr_oos = L2TP_SKB_CB(skb)->ns;
549 u32 nr_next = (session->nr_oos + 1) & session->nr_max;
551 if (nr_oos == nr_next)
552 session->nr_oos_count++;
554 session->nr_oos_count = 0;
556 session->nr_oos = nr_oos;
557 if (session->nr_oos_count > session->nr_oos_count_max) {
558 session->reorder_skip = 1;
559 l2tp_dbg(session, L2TP_MSG_SEQ,
560 "%s: %d oos packets received. Resetting sequence numbers\n",
561 session->name, session->nr_oos_count);
563 if (!session->reorder_skip) {
564 atomic_long_inc(&session->stats.rx_seq_discards);
565 l2tp_dbg(session, L2TP_MSG_SEQ,
566 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
567 session->name, L2TP_SKB_CB(skb)->ns,
568 L2TP_SKB_CB(skb)->length, session->nr,
569 skb_queue_len(&session->reorder_q));
572 skb_queue_tail(&session->reorder_q, skb);
582 /* Do receive processing of L2TP data frames. We handle both L2TPv2
583 * and L2TPv3 data frames here.
585 * L2TPv2 Data Message Header
588 * 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
589 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
590 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
591 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
592 * | Tunnel ID | Session ID |
593 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
594 * | Ns (opt) | Nr (opt) |
595 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
596 * | Offset Size (opt) | Offset pad... (opt)
597 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
599 * Data frames are marked by T=0. All other fields are the same as
600 * those in L2TP control frames.
602 * L2TPv3 Data Message Header
604 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
605 * | L2TP Session Header |
606 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
607 * | L2-Specific Sublayer |
608 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
609 * | Tunnel Payload ...
610 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
612 * L2TPv3 Session Header Over IP
615 * 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
616 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
618 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
619 * | Cookie (optional, maximum 64 bits)...
620 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
622 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
624 * L2TPv3 L2-Specific Sublayer Format
627 * 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
628 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
629 * |x|S|x|x|x|x|x|x| Sequence Number |
630 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
632 * Cookie value and sublayer format are negotiated with the peer when
633 * the session is set up. Unlike L2TPv2, we do not need to parse the
634 * packet header to determine if optional fields are present.
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 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
642 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
643 int length, int (*payload_hook)(struct sk_buff *skb))
645 struct l2tp_tunnel *tunnel = session->tunnel;
649 /* Parse and check optional cookie */
650 if (session->peer_cookie_len > 0) {
651 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
652 l2tp_info(tunnel, L2TP_MSG_DATA,
653 "%s: cookie mismatch (%u/%u). Discarding.\n",
654 tunnel->name, tunnel->tunnel_id,
655 session->session_id);
656 atomic_long_inc(&session->stats.rx_cookie_discards);
659 ptr += session->peer_cookie_len;
662 /* Handle the optional sequence numbers. Sequence numbers are
663 * in different places for L2TPv2 and L2TPv3.
665 * If we are the LAC, enable/disable sequence numbers under
666 * the control of the LNS. If no sequence numbers present but
667 * we were expecting them, discard frame.
670 L2TP_SKB_CB(skb)->has_seq = 0;
671 if (tunnel->version == L2TP_HDR_VER_2) {
672 if (hdrflags & L2TP_HDRFLAG_S) {
673 ns = ntohs(*(__be16 *) ptr);
675 nr = ntohs(*(__be16 *) ptr);
678 /* Store L2TP info in the skb */
679 L2TP_SKB_CB(skb)->ns = ns;
680 L2TP_SKB_CB(skb)->has_seq = 1;
682 l2tp_dbg(session, L2TP_MSG_SEQ,
683 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
684 session->name, ns, nr, session->nr);
686 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
687 u32 l2h = ntohl(*(__be32 *) ptr);
689 if (l2h & 0x40000000) {
690 ns = l2h & 0x00ffffff;
692 /* Store L2TP info in the skb */
693 L2TP_SKB_CB(skb)->ns = ns;
694 L2TP_SKB_CB(skb)->has_seq = 1;
696 l2tp_dbg(session, L2TP_MSG_SEQ,
697 "%s: recv data ns=%u, session nr=%u\n",
698 session->name, ns, session->nr);
703 if (L2TP_SKB_CB(skb)->has_seq) {
704 /* Received a packet with sequence numbers. If we're the LNS,
705 * check if we sre sending sequence numbers and if not,
708 if ((!session->lns_mode) && (!session->send_seq)) {
709 l2tp_info(session, L2TP_MSG_SEQ,
710 "%s: requested to enable seq numbers by LNS\n",
712 session->send_seq = 1;
713 l2tp_session_set_header_len(session, tunnel->version);
716 /* No sequence numbers.
717 * If user has configured mandatory sequence numbers, discard.
719 if (session->recv_seq) {
720 l2tp_warn(session, L2TP_MSG_SEQ,
721 "%s: recv data has no seq numbers when required. Discarding.\n",
723 atomic_long_inc(&session->stats.rx_seq_discards);
727 /* If we're the LAC and we're sending sequence numbers, the
728 * LNS has requested that we no longer send sequence numbers.
729 * If we're the LNS and we're sending sequence numbers, the
730 * LAC is broken. Discard the frame.
732 if ((!session->lns_mode) && (session->send_seq)) {
733 l2tp_info(session, L2TP_MSG_SEQ,
734 "%s: requested to disable seq numbers by LNS\n",
736 session->send_seq = 0;
737 l2tp_session_set_header_len(session, tunnel->version);
738 } else if (session->send_seq) {
739 l2tp_warn(session, L2TP_MSG_SEQ,
740 "%s: recv data has no seq numbers when required. Discarding.\n",
742 atomic_long_inc(&session->stats.rx_seq_discards);
747 /* Session data offset is defined only for L2TPv2 and is
748 * indicated by an optional 16-bit value in the header.
750 if (tunnel->version == L2TP_HDR_VER_2) {
751 /* If offset bit set, skip it. */
752 if (hdrflags & L2TP_HDRFLAG_O) {
753 offset = ntohs(*(__be16 *)ptr);
759 if (!pskb_may_pull(skb, offset))
762 __skb_pull(skb, offset);
764 /* If caller wants to process the payload before we queue the
768 if ((*payload_hook)(skb))
771 /* Prepare skb for adding to the session's reorder_q. Hold
772 * packets for max reorder_timeout or 1 second if not
775 L2TP_SKB_CB(skb)->length = length;
776 L2TP_SKB_CB(skb)->expires = jiffies +
777 (session->reorder_timeout ? session->reorder_timeout : HZ);
779 /* Add packet to the session's receive queue. Reordering is done here, if
780 * enabled. Saved L2TP protocol info is stored in skb->sb[].
782 if (L2TP_SKB_CB(skb)->has_seq) {
783 if (l2tp_recv_data_seq(session, skb))
786 /* No sequence numbers. Add the skb to the tail of the
787 * reorder queue. This ensures that it will be
788 * delivered after all previous sequenced skbs.
790 skb_queue_tail(&session->reorder_q, skb);
793 /* Try to dequeue as many skbs from reorder_q as we can. */
794 l2tp_recv_dequeue(session);
799 atomic_long_inc(&session->stats.rx_errors);
802 EXPORT_SYMBOL(l2tp_recv_common);
804 /* Drop skbs from the session's reorder_q
806 int l2tp_session_queue_purge(struct l2tp_session *session)
808 struct sk_buff *skb = NULL;
810 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
811 while ((skb = skb_dequeue(&session->reorder_q))) {
812 atomic_long_inc(&session->stats.rx_errors);
817 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge);
819 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
820 * here. The skb is not on a list when we get here.
821 * Returns 0 if the packet was a data packet and was successfully passed on.
822 * Returns 1 if the packet was not a good data packet and could not be
823 * forwarded. All such packets are passed up to userspace to deal with.
825 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
826 int (*payload_hook)(struct sk_buff *skb))
828 struct l2tp_session *session = NULL;
829 unsigned char *ptr, *optr;
831 u32 tunnel_id, session_id;
835 /* UDP has verifed checksum */
837 /* UDP always verifies the packet length. */
838 __skb_pull(skb, sizeof(struct udphdr));
841 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
842 l2tp_info(tunnel, L2TP_MSG_DATA,
843 "%s: recv short packet (len=%d)\n",
844 tunnel->name, skb->len);
848 /* Trace packet contents, if enabled */
849 if (tunnel->debug & L2TP_MSG_DATA) {
850 length = min(32u, skb->len);
851 if (!pskb_may_pull(skb, length))
854 pr_debug("%s: recv\n", tunnel->name);
855 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
858 /* Point to L2TP header */
859 optr = ptr = skb->data;
861 /* Get L2TP header flags */
862 hdrflags = ntohs(*(__be16 *) ptr);
864 /* Check protocol version */
865 version = hdrflags & L2TP_HDR_VER_MASK;
866 if (version != tunnel->version) {
867 l2tp_info(tunnel, L2TP_MSG_DATA,
868 "%s: recv protocol version mismatch: got %d expected %d\n",
869 tunnel->name, version, tunnel->version);
873 /* Get length of L2TP packet */
876 /* If type is control packet, it is handled by userspace. */
877 if (hdrflags & L2TP_HDRFLAG_T) {
878 l2tp_dbg(tunnel, L2TP_MSG_DATA,
879 "%s: recv control packet, len=%d\n",
880 tunnel->name, length);
887 if (tunnel->version == L2TP_HDR_VER_2) {
888 /* If length is present, skip it */
889 if (hdrflags & L2TP_HDRFLAG_L)
892 /* Extract tunnel and session ID */
893 tunnel_id = ntohs(*(__be16 *) ptr);
895 session_id = ntohs(*(__be16 *) ptr);
898 ptr += 2; /* skip reserved bits */
899 tunnel_id = tunnel->tunnel_id;
900 session_id = ntohl(*(__be32 *) ptr);
904 /* Find the session context */
905 session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id);
906 if (!session || !session->recv_skb) {
908 l2tp_session_dec_refcount(session);
910 /* Not found? Pass to userspace to deal with */
911 l2tp_info(tunnel, L2TP_MSG_DATA,
912 "%s: no session found (%u/%u). Passing up.\n",
913 tunnel->name, tunnel_id, session_id);
917 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
918 l2tp_session_dec_refcount(session);
923 /* Put UDP header back */
924 __skb_push(skb, sizeof(struct udphdr));
929 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
933 * >0: skb should be passed up to userspace as UDP.
935 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
937 struct l2tp_tunnel *tunnel;
939 tunnel = l2tp_tunnel(sk);
943 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
944 tunnel->name, skb->len);
946 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
954 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
956 /************************************************************************
958 ***********************************************************************/
960 /* Build an L2TP header for the session into the buffer provided.
962 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
964 struct l2tp_tunnel *tunnel = session->tunnel;
967 u16 flags = L2TP_HDR_VER_2;
968 u32 tunnel_id = tunnel->peer_tunnel_id;
969 u32 session_id = session->peer_session_id;
971 if (session->send_seq)
972 flags |= L2TP_HDRFLAG_S;
974 /* Setup L2TP header. */
975 *bufp++ = htons(flags);
976 *bufp++ = htons(tunnel_id);
977 *bufp++ = htons(session_id);
978 if (session->send_seq) {
979 *bufp++ = htons(session->ns);
982 session->ns &= 0xffff;
983 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
984 session->name, session->ns);
990 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
992 struct l2tp_tunnel *tunnel = session->tunnel;
996 /* Setup L2TP header. The header differs slightly for UDP and
997 * IP encapsulations. For UDP, there is 4 bytes of flags.
999 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1000 u16 flags = L2TP_HDR_VER_3;
1001 *((__be16 *) bufp) = htons(flags);
1003 *((__be16 *) bufp) = 0;
1007 *((__be32 *) bufp) = htonl(session->peer_session_id);
1009 if (session->cookie_len) {
1010 memcpy(bufp, &session->cookie[0], session->cookie_len);
1011 bufp += session->cookie_len;
1013 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
1016 if (session->send_seq) {
1017 l2h = 0x40000000 | session->ns;
1019 session->ns &= 0xffffff;
1020 l2tp_dbg(session, L2TP_MSG_SEQ,
1021 "%s: updated ns to %u\n",
1022 session->name, session->ns);
1025 *((__be32 *)bufp) = htonl(l2h);
1032 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1033 struct flowi *fl, size_t data_len)
1035 struct l2tp_tunnel *tunnel = session->tunnel;
1036 unsigned int len = skb->len;
1040 if (session->send_seq)
1041 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes, ns=%u\n",
1042 session->name, data_len, session->ns - 1);
1044 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes\n",
1045 session->name, data_len);
1047 if (session->debug & L2TP_MSG_DATA) {
1048 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1049 unsigned char *datap = skb->data + uhlen;
1051 pr_debug("%s: xmit\n", session->name);
1052 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
1053 datap, min_t(size_t, 32, len - uhlen));
1056 /* Queue the packet to IP for output */
1058 #if IS_ENABLED(CONFIG_IPV6)
1059 if (l2tp_sk_is_v6(tunnel->sock))
1060 error = inet6_csk_xmit(tunnel->sock, skb, NULL);
1063 error = ip_queue_xmit(tunnel->sock, skb, fl);
1067 atomic_long_inc(&tunnel->stats.tx_packets);
1068 atomic_long_add(len, &tunnel->stats.tx_bytes);
1069 atomic_long_inc(&session->stats.tx_packets);
1070 atomic_long_add(len, &session->stats.tx_bytes);
1072 atomic_long_inc(&tunnel->stats.tx_errors);
1073 atomic_long_inc(&session->stats.tx_errors);
1079 /* If caller requires the skb to have a ppp header, the header must be
1080 * inserted in the skb data before calling this function.
1082 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1084 int data_len = skb->len;
1085 struct l2tp_tunnel *tunnel = session->tunnel;
1086 struct sock *sk = tunnel->sock;
1089 struct inet_sock *inet;
1091 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1093 int ret = NET_XMIT_SUCCESS;
1095 /* Check that there's enough headroom in the skb to insert IP,
1096 * UDP and L2TP headers. If not enough, expand it to
1097 * make room. Adjust truesize.
1099 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1101 if (skb_cow_head(skb, headroom)) {
1103 return NET_XMIT_DROP;
1106 /* Setup L2TP header */
1107 session->build_header(session, __skb_push(skb, hdr_len));
1109 /* Reset skb netfilter state */
1110 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1111 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1116 if (sock_owned_by_user(sk)) {
1118 ret = NET_XMIT_DROP;
1122 /* The user-space may change the connection status for the user-space
1123 * provided socket at run time: we must check it under the socket lock
1125 if (tunnel->fd >= 0 && sk->sk_state != TCP_ESTABLISHED) {
1127 ret = NET_XMIT_DROP;
1131 /* Get routing info from the tunnel socket */
1133 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
1136 fl = &inet->cork.fl;
1137 switch (tunnel->encap) {
1138 case L2TP_ENCAPTYPE_UDP:
1139 /* Setup UDP header */
1140 __skb_push(skb, sizeof(*uh));
1141 skb_reset_transport_header(skb);
1143 uh->source = inet->inet_sport;
1144 uh->dest = inet->inet_dport;
1145 udp_len = uhlen + hdr_len + data_len;
1146 uh->len = htons(udp_len);
1148 /* Calculate UDP checksum if configured to do so */
1149 #if IS_ENABLED(CONFIG_IPV6)
1150 if (l2tp_sk_is_v6(sk))
1151 udp6_set_csum(udp_get_no_check6_tx(sk),
1152 skb, &inet6_sk(sk)->saddr,
1153 &sk->sk_v6_daddr, udp_len);
1156 udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr,
1157 inet->inet_daddr, udp_len);
1160 case L2TP_ENCAPTYPE_IP:
1164 l2tp_xmit_core(session, skb, fl, data_len);
1170 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1172 /*****************************************************************************
1173 * Tinnel and session create/destroy.
1174 *****************************************************************************/
1176 /* Tunnel socket destruct hook.
1177 * The tunnel context is deleted only when all session sockets have been
1180 static void l2tp_tunnel_destruct(struct sock *sk)
1182 struct l2tp_tunnel *tunnel = l2tp_tunnel(sk);
1187 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
1189 /* Disable udp encapsulation */
1190 switch (tunnel->encap) {
1191 case L2TP_ENCAPTYPE_UDP:
1192 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1193 (udp_sk(sk))->encap_type = 0;
1194 (udp_sk(sk))->encap_rcv = NULL;
1195 (udp_sk(sk))->encap_destroy = NULL;
1197 case L2TP_ENCAPTYPE_IP:
1201 /* Remove hooks into tunnel socket */
1202 sk->sk_destruct = tunnel->old_sk_destruct;
1203 sk->sk_user_data = NULL;
1205 /* Call the original destructor */
1206 if (sk->sk_destruct)
1207 (*sk->sk_destruct)(sk);
1209 kfree_rcu(tunnel, rcu);
1214 /* When the tunnel is closed, all the attached sessions need to go too.
1216 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1219 struct hlist_node *walk;
1220 struct hlist_node *tmp;
1221 struct l2tp_session *session;
1223 BUG_ON(tunnel == NULL);
1225 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
1228 write_lock_bh(&tunnel->hlist_lock);
1229 tunnel->acpt_newsess = false;
1230 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1232 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1233 session = hlist_entry(walk, struct l2tp_session, hlist);
1235 l2tp_info(session, L2TP_MSG_CONTROL,
1236 "%s: closing session\n", session->name);
1238 hlist_del_init(&session->hlist);
1240 if (test_and_set_bit(0, &session->dead))
1243 write_unlock_bh(&tunnel->hlist_lock);
1245 __l2tp_session_unhash(session);
1246 l2tp_session_queue_purge(session);
1248 if (session->session_close != NULL)
1249 (*session->session_close)(session);
1251 l2tp_session_dec_refcount(session);
1253 write_lock_bh(&tunnel->hlist_lock);
1255 /* Now restart from the beginning of this hash
1256 * chain. We always remove a session from the
1257 * list so we are guaranteed to make forward
1263 write_unlock_bh(&tunnel->hlist_lock);
1265 EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall);
1267 /* Tunnel socket destroy hook for UDP encapsulation */
1268 static void l2tp_udp_encap_destroy(struct sock *sk)
1270 struct l2tp_tunnel *tunnel = l2tp_tunnel(sk);
1273 l2tp_tunnel_delete(tunnel);
1276 /* Workqueue tunnel deletion function */
1277 static void l2tp_tunnel_del_work(struct work_struct *work)
1279 struct l2tp_tunnel *tunnel = container_of(work, struct l2tp_tunnel,
1281 struct sock *sk = tunnel->sock;
1282 struct socket *sock = sk->sk_socket;
1283 struct l2tp_net *pn;
1285 l2tp_tunnel_closeall(tunnel);
1287 /* If the tunnel socket was created within the kernel, use
1288 * the sk API to release it here.
1290 if (tunnel->fd < 0) {
1292 kernel_sock_shutdown(sock, SHUT_RDWR);
1297 /* Remove the tunnel struct from the tunnel list */
1298 pn = l2tp_pernet(tunnel->l2tp_net);
1299 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1300 list_del_rcu(&tunnel->list);
1301 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1303 /* drop initial ref */
1304 l2tp_tunnel_dec_refcount(tunnel);
1306 /* drop workqueue ref */
1307 l2tp_tunnel_dec_refcount(tunnel);
1310 /* Create a socket for the tunnel, if one isn't set up by
1311 * userspace. This is used for static tunnels where there is no
1312 * managing L2TP daemon.
1314 * Since we don't want these sockets to keep a namespace alive by
1315 * themselves, we drop the socket's namespace refcount after creation.
1316 * These sockets are freed when the namespace exits using the pernet
1319 static int l2tp_tunnel_sock_create(struct net *net,
1322 struct l2tp_tunnel_cfg *cfg,
1323 struct socket **sockp)
1326 struct socket *sock = NULL;
1327 struct udp_port_cfg udp_conf;
1329 switch (cfg->encap) {
1330 case L2TP_ENCAPTYPE_UDP:
1331 memset(&udp_conf, 0, sizeof(udp_conf));
1333 #if IS_ENABLED(CONFIG_IPV6)
1334 if (cfg->local_ip6 && cfg->peer_ip6) {
1335 udp_conf.family = AF_INET6;
1336 memcpy(&udp_conf.local_ip6, cfg->local_ip6,
1337 sizeof(udp_conf.local_ip6));
1338 memcpy(&udp_conf.peer_ip6, cfg->peer_ip6,
1339 sizeof(udp_conf.peer_ip6));
1340 udp_conf.use_udp6_tx_checksums =
1341 ! cfg->udp6_zero_tx_checksums;
1342 udp_conf.use_udp6_rx_checksums =
1343 ! cfg->udp6_zero_rx_checksums;
1347 udp_conf.family = AF_INET;
1348 udp_conf.local_ip = cfg->local_ip;
1349 udp_conf.peer_ip = cfg->peer_ip;
1350 udp_conf.use_udp_checksums = cfg->use_udp_checksums;
1353 udp_conf.local_udp_port = htons(cfg->local_udp_port);
1354 udp_conf.peer_udp_port = htons(cfg->peer_udp_port);
1356 err = udp_sock_create(net, &udp_conf, &sock);
1362 case L2TP_ENCAPTYPE_IP:
1363 #if IS_ENABLED(CONFIG_IPV6)
1364 if (cfg->local_ip6 && cfg->peer_ip6) {
1365 struct sockaddr_l2tpip6 ip6_addr = {0};
1367 err = sock_create_kern(net, AF_INET6, SOCK_DGRAM,
1368 IPPROTO_L2TP, &sock);
1372 ip6_addr.l2tp_family = AF_INET6;
1373 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
1374 sizeof(ip6_addr.l2tp_addr));
1375 ip6_addr.l2tp_conn_id = tunnel_id;
1376 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
1381 ip6_addr.l2tp_family = AF_INET6;
1382 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
1383 sizeof(ip6_addr.l2tp_addr));
1384 ip6_addr.l2tp_conn_id = peer_tunnel_id;
1385 err = kernel_connect(sock,
1386 (struct sockaddr *) &ip6_addr,
1387 sizeof(ip6_addr), 0);
1393 struct sockaddr_l2tpip ip_addr = {0};
1395 err = sock_create_kern(net, AF_INET, SOCK_DGRAM,
1396 IPPROTO_L2TP, &sock);
1400 ip_addr.l2tp_family = AF_INET;
1401 ip_addr.l2tp_addr = cfg->local_ip;
1402 ip_addr.l2tp_conn_id = tunnel_id;
1403 err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
1408 ip_addr.l2tp_family = AF_INET;
1409 ip_addr.l2tp_addr = cfg->peer_ip;
1410 ip_addr.l2tp_conn_id = peer_tunnel_id;
1411 err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
1412 sizeof(ip_addr), 0);
1424 if ((err < 0) && sock) {
1425 kernel_sock_shutdown(sock, SHUT_RDWR);
1433 static struct lock_class_key l2tp_socket_class;
1435 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)
1437 struct l2tp_tunnel *tunnel = NULL;
1439 struct socket *sock = NULL;
1440 struct sock *sk = NULL;
1441 struct l2tp_net *pn;
1442 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1444 /* Get the tunnel socket from the fd, which was opened by
1445 * the userspace L2TP daemon. If not specified, create a
1449 err = l2tp_tunnel_sock_create(net, tunnel_id, peer_tunnel_id,
1454 sock = sockfd_lookup(fd, &err);
1456 pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n",
1457 tunnel_id, fd, err);
1462 /* Reject namespace mismatches */
1463 if (!net_eq(sock_net(sock->sk), net)) {
1464 pr_err("tunl %u: netns mismatch\n", tunnel_id);
1475 /* Quick sanity checks */
1476 err = -EPROTONOSUPPORT;
1477 if (sk->sk_type != SOCK_DGRAM) {
1478 pr_debug("tunl %hu: fd %d wrong socket type\n",
1483 case L2TP_ENCAPTYPE_UDP:
1484 if (sk->sk_protocol != IPPROTO_UDP) {
1485 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1486 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1490 case L2TP_ENCAPTYPE_IP:
1491 if (sk->sk_protocol != IPPROTO_L2TP) {
1492 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1493 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1499 /* Check if this socket has already been prepped */
1500 tunnel = l2tp_tunnel(sk);
1501 if (tunnel != NULL) {
1502 /* This socket has already been prepped */
1507 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1508 if (tunnel == NULL) {
1513 tunnel->version = version;
1514 tunnel->tunnel_id = tunnel_id;
1515 tunnel->peer_tunnel_id = peer_tunnel_id;
1516 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1518 tunnel->magic = L2TP_TUNNEL_MAGIC;
1519 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1520 rwlock_init(&tunnel->hlist_lock);
1521 tunnel->acpt_newsess = true;
1523 /* The net we belong to */
1524 tunnel->l2tp_net = net;
1525 pn = l2tp_pernet(net);
1528 tunnel->debug = cfg->debug;
1530 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1531 tunnel->encap = encap;
1532 if (encap == L2TP_ENCAPTYPE_UDP) {
1533 struct udp_tunnel_sock_cfg udp_cfg = { };
1535 udp_cfg.sk_user_data = tunnel;
1536 udp_cfg.encap_type = UDP_ENCAP_L2TPINUDP;
1537 udp_cfg.encap_rcv = l2tp_udp_encap_recv;
1538 udp_cfg.encap_destroy = l2tp_udp_encap_destroy;
1540 setup_udp_tunnel_sock(net, sock, &udp_cfg);
1542 sk->sk_user_data = tunnel;
1545 /* Bump the reference count. The tunnel context is deleted
1546 * only when this drops to zero. A reference is also held on
1547 * the tunnel socket to ensure that it is not released while
1548 * the tunnel is extant. Must be done before sk_destruct is
1551 refcount_set(&tunnel->ref_count, 1);
1556 /* Hook on the tunnel socket destructor so that we can cleanup
1557 * if the tunnel socket goes away.
1559 tunnel->old_sk_destruct = sk->sk_destruct;
1560 sk->sk_destruct = &l2tp_tunnel_destruct;
1561 lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock");
1563 sk->sk_allocation = GFP_ATOMIC;
1565 /* Init delete workqueue struct */
1566 INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work);
1568 /* Add tunnel to our list */
1569 INIT_LIST_HEAD(&tunnel->list);
1570 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1571 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1572 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1579 /* If tunnel's socket was created by the kernel, it doesn't
1582 if (sock && sock->file)
1587 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1589 /* This function is used by the netlink TUNNEL_DELETE command.
1591 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1593 if (!test_and_set_bit(0, &tunnel->dead)) {
1594 l2tp_tunnel_inc_refcount(tunnel);
1595 queue_work(l2tp_wq, &tunnel->del_work);
1598 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1600 /* Really kill the session.
1602 void l2tp_session_free(struct l2tp_session *session)
1604 struct l2tp_tunnel *tunnel = session->tunnel;
1606 BUG_ON(refcount_read(&session->ref_count) != 0);
1609 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1610 l2tp_tunnel_dec_refcount(tunnel);
1615 EXPORT_SYMBOL_GPL(l2tp_session_free);
1617 /* Remove an l2tp session from l2tp_core's hash lists.
1618 * Provides a tidyup interface for pseudowire code which can't just route all
1619 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close
1622 void __l2tp_session_unhash(struct l2tp_session *session)
1624 struct l2tp_tunnel *tunnel = session->tunnel;
1626 /* Remove the session from core hashes */
1628 /* Remove from the per-tunnel hash */
1629 write_lock_bh(&tunnel->hlist_lock);
1630 hlist_del_init(&session->hlist);
1631 write_unlock_bh(&tunnel->hlist_lock);
1633 /* For L2TPv3 we have a per-net hash: remove from there, too */
1634 if (tunnel->version != L2TP_HDR_VER_2) {
1635 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1636 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1637 hlist_del_init_rcu(&session->global_hlist);
1638 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1643 EXPORT_SYMBOL_GPL(__l2tp_session_unhash);
1645 /* This function is used by the netlink SESSION_DELETE command and by
1648 int l2tp_session_delete(struct l2tp_session *session)
1650 if (test_and_set_bit(0, &session->dead))
1653 __l2tp_session_unhash(session);
1654 l2tp_session_queue_purge(session);
1655 if (session->session_close != NULL)
1656 (*session->session_close)(session);
1658 l2tp_session_dec_refcount(session);
1662 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1664 /* We come here whenever a session's send_seq, cookie_len or
1665 * l2specific_type parameters are set.
1667 void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1669 if (version == L2TP_HDR_VER_2) {
1670 session->hdr_len = 6;
1671 if (session->send_seq)
1672 session->hdr_len += 4;
1674 session->hdr_len = 4 + session->cookie_len;
1675 session->hdr_len += l2tp_get_l2specific_len(session);
1676 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1677 session->hdr_len += 4;
1681 EXPORT_SYMBOL_GPL(l2tp_session_set_header_len);
1683 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)
1685 struct l2tp_session *session;
1687 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1688 if (session != NULL) {
1689 session->magic = L2TP_SESSION_MAGIC;
1690 session->tunnel = tunnel;
1692 session->session_id = session_id;
1693 session->peer_session_id = peer_session_id;
1695 if (tunnel->version == L2TP_HDR_VER_2)
1696 session->nr_max = 0xffff;
1698 session->nr_max = 0xffffff;
1699 session->nr_window_size = session->nr_max / 2;
1700 session->nr_oos_count_max = 4;
1702 /* Use NR of first received packet */
1703 session->reorder_skip = 1;
1705 sprintf(&session->name[0], "sess %u/%u",
1706 tunnel->tunnel_id, session->session_id);
1708 skb_queue_head_init(&session->reorder_q);
1710 INIT_HLIST_NODE(&session->hlist);
1711 INIT_HLIST_NODE(&session->global_hlist);
1713 /* Inherit debug options from tunnel */
1714 session->debug = tunnel->debug;
1717 session->pwtype = cfg->pw_type;
1718 session->debug = cfg->debug;
1719 session->mtu = cfg->mtu;
1720 session->mru = cfg->mru;
1721 session->send_seq = cfg->send_seq;
1722 session->recv_seq = cfg->recv_seq;
1723 session->lns_mode = cfg->lns_mode;
1724 session->reorder_timeout = cfg->reorder_timeout;
1725 session->l2specific_type = cfg->l2specific_type;
1726 session->cookie_len = cfg->cookie_len;
1727 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1728 session->peer_cookie_len = cfg->peer_cookie_len;
1729 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1732 if (tunnel->version == L2TP_HDR_VER_2)
1733 session->build_header = l2tp_build_l2tpv2_header;
1735 session->build_header = l2tp_build_l2tpv3_header;
1737 l2tp_session_set_header_len(session, tunnel->version);
1739 refcount_set(&session->ref_count, 1);
1744 return ERR_PTR(-ENOMEM);
1746 EXPORT_SYMBOL_GPL(l2tp_session_create);
1748 /*****************************************************************************
1750 *****************************************************************************/
1752 static __net_init int l2tp_init_net(struct net *net)
1754 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1757 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1758 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1760 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1761 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1763 spin_lock_init(&pn->l2tp_session_hlist_lock);
1768 static __net_exit void l2tp_exit_net(struct net *net)
1770 struct l2tp_net *pn = l2tp_pernet(net);
1771 struct l2tp_tunnel *tunnel = NULL;
1775 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
1776 l2tp_tunnel_delete(tunnel);
1778 rcu_read_unlock_bh();
1780 flush_workqueue(l2tp_wq);
1783 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1784 WARN_ON_ONCE(!hlist_empty(&pn->l2tp_session_hlist[hash]));
1787 static struct pernet_operations l2tp_net_ops = {
1788 .init = l2tp_init_net,
1789 .exit = l2tp_exit_net,
1791 .size = sizeof(struct l2tp_net),
1794 static int __init l2tp_init(void)
1798 rc = register_pernet_device(&l2tp_net_ops);
1802 l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0);
1804 pr_err("alloc_workqueue failed\n");
1805 unregister_pernet_device(&l2tp_net_ops);
1810 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
1816 static void __exit l2tp_exit(void)
1818 unregister_pernet_device(&l2tp_net_ops);
1820 destroy_workqueue(l2tp_wq);
1825 module_init(l2tp_init);
1826 module_exit(l2tp_exit);
1828 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1829 MODULE_DESCRIPTION("L2TP core");
1830 MODULE_LICENSE("GPL");
1831 MODULE_VERSION(L2TP_DRV_VERSION);