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 atomic_t l2tp_tunnel_count;
104 static atomic_t l2tp_session_count;
105 static struct workqueue_struct *l2tp_wq;
107 /* per-net private data for this module */
108 static unsigned int l2tp_net_id;
110 struct list_head l2tp_tunnel_list;
111 spinlock_t l2tp_tunnel_list_lock;
112 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
113 spinlock_t l2tp_session_hlist_lock;
116 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
118 static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk)
120 return sk->sk_user_data;
123 static inline struct l2tp_net *l2tp_pernet(const struct net *net)
127 return net_generic(net, l2tp_net_id);
130 /* Tunnel reference counts. Incremented per session that is added to
133 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
135 atomic_inc(&tunnel->ref_count);
138 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
140 if (atomic_dec_and_test(&tunnel->ref_count))
141 l2tp_tunnel_free(tunnel);
143 #ifdef L2TP_REFCNT_DEBUG
144 #define l2tp_tunnel_inc_refcount(_t) \
146 pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \
147 __func__, __LINE__, (_t)->name, \
148 atomic_read(&_t->ref_count)); \
149 l2tp_tunnel_inc_refcount_1(_t); \
151 #define l2tp_tunnel_dec_refcount(_t) \
153 pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \
154 __func__, __LINE__, (_t)->name, \
155 atomic_read(&_t->ref_count)); \
156 l2tp_tunnel_dec_refcount_1(_t); \
159 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
160 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
163 /* Session hash global list for L2TPv3.
164 * The session_id SHOULD be random according to RFC3931, but several
165 * L2TP implementations use incrementing session_ids. So we do a real
166 * hash on the session_id, rather than a simple bitmask.
168 static inline struct hlist_head *
169 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
171 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
175 /* Lookup the tunnel socket, possibly involving the fs code if the socket is
176 * owned by userspace. A struct sock returned from this function must be
177 * released using l2tp_tunnel_sock_put once you're done with it.
179 static struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel)
182 struct socket *sock = NULL;
183 struct sock *sk = NULL;
188 if (tunnel->fd >= 0) {
189 /* Socket is owned by userspace, who might be in the process
190 * of closing it. Look the socket up using the fd to ensure
193 sock = sockfd_lookup(tunnel->fd, &err);
197 /* Socket is owned by kernelspace */
206 /* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */
207 static void l2tp_tunnel_sock_put(struct sock *sk)
209 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
211 if (tunnel->fd >= 0) {
212 /* Socket is owned by userspace */
213 sockfd_put(sk->sk_socket);
220 /* Session hash list.
221 * The session_id SHOULD be random according to RFC2661, but several
222 * L2TP implementations (Cisco and Microsoft) use incrementing
223 * session_ids. So we do a real hash on the session_id, rather than a
226 static inline struct hlist_head *
227 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
229 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
232 /* Lookup a session. A new reference is held on the returned session.
233 * Optionally calls session->ref() too if do_ref is true.
235 struct l2tp_session *l2tp_session_get(const struct net *net,
236 struct l2tp_tunnel *tunnel,
237 u32 session_id, bool do_ref)
239 struct hlist_head *session_list;
240 struct l2tp_session *session;
243 struct l2tp_net *pn = l2tp_pernet(net);
245 session_list = l2tp_session_id_hash_2(pn, session_id);
248 hlist_for_each_entry_rcu(session, session_list, global_hlist) {
249 if (session->session_id == session_id) {
250 l2tp_session_inc_refcount(session);
251 if (do_ref && session->ref)
252 session->ref(session);
253 rcu_read_unlock_bh();
258 rcu_read_unlock_bh();
263 session_list = l2tp_session_id_hash(tunnel, session_id);
264 read_lock_bh(&tunnel->hlist_lock);
265 hlist_for_each_entry(session, session_list, hlist) {
266 if (session->session_id == session_id) {
267 l2tp_session_inc_refcount(session);
268 if (do_ref && session->ref)
269 session->ref(session);
270 read_unlock_bh(&tunnel->hlist_lock);
275 read_unlock_bh(&tunnel->hlist_lock);
279 EXPORT_SYMBOL_GPL(l2tp_session_get);
281 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
285 struct l2tp_session *session;
288 read_lock_bh(&tunnel->hlist_lock);
289 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
290 hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) {
292 l2tp_session_inc_refcount(session);
293 if (do_ref && session->ref)
294 session->ref(session);
295 read_unlock_bh(&tunnel->hlist_lock);
301 read_unlock_bh(&tunnel->hlist_lock);
305 EXPORT_SYMBOL_GPL(l2tp_session_get_nth);
307 /* Lookup a session by interface name.
308 * This is very inefficient but is only used by management interfaces.
310 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
314 struct l2tp_net *pn = l2tp_pernet(net);
316 struct l2tp_session *session;
319 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
320 hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) {
321 if (!strcmp(session->ifname, ifname)) {
322 l2tp_session_inc_refcount(session);
323 if (do_ref && session->ref)
324 session->ref(session);
325 rcu_read_unlock_bh();
332 rcu_read_unlock_bh();
336 EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname);
338 static int l2tp_session_add_to_tunnel(struct l2tp_tunnel *tunnel,
339 struct l2tp_session *session)
341 struct l2tp_session *session_walk;
342 struct hlist_head *g_head;
343 struct hlist_head *head;
346 head = l2tp_session_id_hash(tunnel, session->session_id);
348 write_lock_bh(&tunnel->hlist_lock);
349 hlist_for_each_entry(session_walk, head, hlist)
350 if (session_walk->session_id == session->session_id)
353 if (tunnel->version == L2TP_HDR_VER_3) {
354 pn = l2tp_pernet(tunnel->l2tp_net);
355 g_head = l2tp_session_id_hash_2(l2tp_pernet(tunnel->l2tp_net),
356 session->session_id);
358 spin_lock_bh(&pn->l2tp_session_hlist_lock);
359 hlist_for_each_entry(session_walk, g_head, global_hlist)
360 if (session_walk->session_id == session->session_id)
363 hlist_add_head_rcu(&session->global_hlist, g_head);
364 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
367 hlist_add_head(&session->hlist, head);
368 write_unlock_bh(&tunnel->hlist_lock);
373 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
375 write_unlock_bh(&tunnel->hlist_lock);
380 /* Lookup a tunnel by id
382 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id)
384 struct l2tp_tunnel *tunnel;
385 struct l2tp_net *pn = l2tp_pernet(net);
388 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
389 if (tunnel->tunnel_id == tunnel_id) {
390 rcu_read_unlock_bh();
394 rcu_read_unlock_bh();
398 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
400 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth)
402 struct l2tp_net *pn = l2tp_pernet(net);
403 struct l2tp_tunnel *tunnel;
407 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
409 rcu_read_unlock_bh();
414 rcu_read_unlock_bh();
418 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
420 /*****************************************************************************
421 * Receive data handling
422 *****************************************************************************/
424 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
427 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
429 struct sk_buff *skbp;
431 u32 ns = L2TP_SKB_CB(skb)->ns;
433 spin_lock_bh(&session->reorder_q.lock);
434 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
435 if (L2TP_SKB_CB(skbp)->ns > ns) {
436 __skb_queue_before(&session->reorder_q, skbp, skb);
437 l2tp_dbg(session, L2TP_MSG_SEQ,
438 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
439 session->name, ns, L2TP_SKB_CB(skbp)->ns,
440 skb_queue_len(&session->reorder_q));
441 atomic_long_inc(&session->stats.rx_oos_packets);
446 __skb_queue_tail(&session->reorder_q, skb);
449 spin_unlock_bh(&session->reorder_q.lock);
452 /* Dequeue a single skb.
454 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
456 struct l2tp_tunnel *tunnel = session->tunnel;
457 int length = L2TP_SKB_CB(skb)->length;
459 /* We're about to requeue the skb, so return resources
460 * to its current owner (a socket receive buffer).
464 atomic_long_inc(&tunnel->stats.rx_packets);
465 atomic_long_add(length, &tunnel->stats.rx_bytes);
466 atomic_long_inc(&session->stats.rx_packets);
467 atomic_long_add(length, &session->stats.rx_bytes);
469 if (L2TP_SKB_CB(skb)->has_seq) {
472 session->nr &= session->nr_max;
474 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
475 session->name, session->nr);
478 /* call private receive handler */
479 if (session->recv_skb != NULL)
480 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
485 (*session->deref)(session);
488 /* Dequeue skbs from the session's reorder_q, subject to packet order.
489 * Skbs that have been in the queue for too long are simply discarded.
491 static void l2tp_recv_dequeue(struct l2tp_session *session)
496 /* If the pkt at the head of the queue has the nr that we
497 * expect to send up next, dequeue it and any other
498 * in-sequence packets behind it.
501 spin_lock_bh(&session->reorder_q.lock);
502 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
503 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
504 atomic_long_inc(&session->stats.rx_seq_discards);
505 atomic_long_inc(&session->stats.rx_errors);
506 l2tp_dbg(session, L2TP_MSG_SEQ,
507 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
508 session->name, L2TP_SKB_CB(skb)->ns,
509 L2TP_SKB_CB(skb)->length, session->nr,
510 skb_queue_len(&session->reorder_q));
511 session->reorder_skip = 1;
512 __skb_unlink(skb, &session->reorder_q);
515 (*session->deref)(session);
519 if (L2TP_SKB_CB(skb)->has_seq) {
520 if (session->reorder_skip) {
521 l2tp_dbg(session, L2TP_MSG_SEQ,
522 "%s: advancing nr to next pkt: %u -> %u",
523 session->name, session->nr,
524 L2TP_SKB_CB(skb)->ns);
525 session->reorder_skip = 0;
526 session->nr = L2TP_SKB_CB(skb)->ns;
528 if (L2TP_SKB_CB(skb)->ns != session->nr) {
529 l2tp_dbg(session, L2TP_MSG_SEQ,
530 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
531 session->name, L2TP_SKB_CB(skb)->ns,
532 L2TP_SKB_CB(skb)->length, session->nr,
533 skb_queue_len(&session->reorder_q));
537 __skb_unlink(skb, &session->reorder_q);
539 /* Process the skb. We release the queue lock while we
540 * do so to let other contexts process the queue.
542 spin_unlock_bh(&session->reorder_q.lock);
543 l2tp_recv_dequeue_skb(session, skb);
548 spin_unlock_bh(&session->reorder_q.lock);
551 static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
555 if (nr >= session->nr)
556 nws = nr - session->nr;
558 nws = (session->nr_max + 1) - (session->nr - nr);
560 return nws < session->nr_window_size;
563 /* If packet has sequence numbers, queue it if acceptable. Returns 0 if
564 * acceptable, else non-zero.
566 static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb)
568 if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) {
569 /* Packet sequence number is outside allowed window.
572 l2tp_dbg(session, L2TP_MSG_SEQ,
573 "%s: pkt %u len %d discarded, outside window, nr=%u\n",
574 session->name, L2TP_SKB_CB(skb)->ns,
575 L2TP_SKB_CB(skb)->length, session->nr);
579 if (session->reorder_timeout != 0) {
580 /* Packet reordering enabled. Add skb to session's
581 * reorder queue, in order of ns.
583 l2tp_recv_queue_skb(session, skb);
587 /* Packet reordering disabled. Discard out-of-sequence packets, while
588 * tracking the number if in-sequence packets after the first OOS packet
589 * is seen. After nr_oos_count_max in-sequence packets, reset the
590 * sequence number to re-enable packet reception.
592 if (L2TP_SKB_CB(skb)->ns == session->nr) {
593 skb_queue_tail(&session->reorder_q, skb);
595 u32 nr_oos = L2TP_SKB_CB(skb)->ns;
596 u32 nr_next = (session->nr_oos + 1) & session->nr_max;
598 if (nr_oos == nr_next)
599 session->nr_oos_count++;
601 session->nr_oos_count = 0;
603 session->nr_oos = nr_oos;
604 if (session->nr_oos_count > session->nr_oos_count_max) {
605 session->reorder_skip = 1;
606 l2tp_dbg(session, L2TP_MSG_SEQ,
607 "%s: %d oos packets received. Resetting sequence numbers\n",
608 session->name, session->nr_oos_count);
610 if (!session->reorder_skip) {
611 atomic_long_inc(&session->stats.rx_seq_discards);
612 l2tp_dbg(session, L2TP_MSG_SEQ,
613 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
614 session->name, L2TP_SKB_CB(skb)->ns,
615 L2TP_SKB_CB(skb)->length, session->nr,
616 skb_queue_len(&session->reorder_q));
619 skb_queue_tail(&session->reorder_q, skb);
629 /* Do receive processing of L2TP data frames. We handle both L2TPv2
630 * and L2TPv3 data frames here.
632 * L2TPv2 Data Message Header
635 * 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
636 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
637 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
638 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
639 * | Tunnel ID | Session ID |
640 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
641 * | Ns (opt) | Nr (opt) |
642 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
643 * | Offset Size (opt) | Offset pad... (opt)
644 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
646 * Data frames are marked by T=0. All other fields are the same as
647 * those in L2TP control frames.
649 * L2TPv3 Data Message Header
651 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
652 * | L2TP Session Header |
653 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
654 * | L2-Specific Sublayer |
655 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
656 * | Tunnel Payload ...
657 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
659 * L2TPv3 Session Header Over IP
662 * 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
663 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
665 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
666 * | Cookie (optional, maximum 64 bits)...
667 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
669 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
671 * L2TPv3 L2-Specific Sublayer Format
674 * 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
675 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
676 * |x|S|x|x|x|x|x|x| Sequence Number |
677 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
679 * Cookie value, sublayer format and offset (pad) are negotiated with
680 * the peer when the session is set up. Unlike L2TPv2, we do not need
681 * to parse the packet header to determine if optional fields are
684 * Caller must already have parsed the frame and determined that it is
685 * a data (not control) frame before coming here. Fields up to the
686 * session-id have already been parsed and ptr points to the data
687 * after the session-id.
689 * session->ref() must have been called prior to l2tp_recv_common().
690 * session->deref() will be called automatically after skb is processed.
692 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
693 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
694 int length, int (*payload_hook)(struct sk_buff *skb))
696 struct l2tp_tunnel *tunnel = session->tunnel;
700 /* Parse and check optional cookie */
701 if (session->peer_cookie_len > 0) {
702 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
703 l2tp_info(tunnel, L2TP_MSG_DATA,
704 "%s: cookie mismatch (%u/%u). Discarding.\n",
705 tunnel->name, tunnel->tunnel_id,
706 session->session_id);
707 atomic_long_inc(&session->stats.rx_cookie_discards);
710 ptr += session->peer_cookie_len;
713 /* Handle the optional sequence numbers. Sequence numbers are
714 * in different places for L2TPv2 and L2TPv3.
716 * If we are the LAC, enable/disable sequence numbers under
717 * the control of the LNS. If no sequence numbers present but
718 * we were expecting them, discard frame.
721 L2TP_SKB_CB(skb)->has_seq = 0;
722 if (tunnel->version == L2TP_HDR_VER_2) {
723 if (hdrflags & L2TP_HDRFLAG_S) {
724 ns = ntohs(*(__be16 *) ptr);
726 nr = ntohs(*(__be16 *) ptr);
729 /* Store L2TP info in the skb */
730 L2TP_SKB_CB(skb)->ns = ns;
731 L2TP_SKB_CB(skb)->has_seq = 1;
733 l2tp_dbg(session, L2TP_MSG_SEQ,
734 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
735 session->name, ns, nr, session->nr);
737 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
738 u32 l2h = ntohl(*(__be32 *) ptr);
740 if (l2h & 0x40000000) {
741 ns = l2h & 0x00ffffff;
743 /* Store L2TP info in the skb */
744 L2TP_SKB_CB(skb)->ns = ns;
745 L2TP_SKB_CB(skb)->has_seq = 1;
747 l2tp_dbg(session, L2TP_MSG_SEQ,
748 "%s: recv data ns=%u, session nr=%u\n",
749 session->name, ns, session->nr);
753 /* Advance past L2-specific header, if present */
754 ptr += session->l2specific_len;
756 if (L2TP_SKB_CB(skb)->has_seq) {
757 /* Received a packet with sequence numbers. If we're the LNS,
758 * check if we sre sending sequence numbers and if not,
761 if ((!session->lns_mode) && (!session->send_seq)) {
762 l2tp_info(session, L2TP_MSG_SEQ,
763 "%s: requested to enable seq numbers by LNS\n",
765 session->send_seq = 1;
766 l2tp_session_set_header_len(session, tunnel->version);
769 /* No sequence numbers.
770 * If user has configured mandatory sequence numbers, discard.
772 if (session->recv_seq) {
773 l2tp_warn(session, L2TP_MSG_SEQ,
774 "%s: recv data has no seq numbers when required. Discarding.\n",
776 atomic_long_inc(&session->stats.rx_seq_discards);
780 /* If we're the LAC and we're sending sequence numbers, the
781 * LNS has requested that we no longer send sequence numbers.
782 * If we're the LNS and we're sending sequence numbers, the
783 * LAC is broken. Discard the frame.
785 if ((!session->lns_mode) && (session->send_seq)) {
786 l2tp_info(session, L2TP_MSG_SEQ,
787 "%s: requested to disable seq numbers by LNS\n",
789 session->send_seq = 0;
790 l2tp_session_set_header_len(session, tunnel->version);
791 } else if (session->send_seq) {
792 l2tp_warn(session, L2TP_MSG_SEQ,
793 "%s: recv data has no seq numbers when required. Discarding.\n",
795 atomic_long_inc(&session->stats.rx_seq_discards);
800 /* Session data offset is handled differently for L2TPv2 and
801 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
802 * the header. For L2TPv3, the offset is negotiated using AVPs
803 * in the session setup control protocol.
805 if (tunnel->version == L2TP_HDR_VER_2) {
806 /* If offset bit set, skip it. */
807 if (hdrflags & L2TP_HDRFLAG_O) {
808 offset = ntohs(*(__be16 *)ptr);
812 ptr += session->offset;
815 if (!pskb_may_pull(skb, offset))
818 __skb_pull(skb, offset);
820 /* If caller wants to process the payload before we queue the
824 if ((*payload_hook)(skb))
827 /* Prepare skb for adding to the session's reorder_q. Hold
828 * packets for max reorder_timeout or 1 second if not
831 L2TP_SKB_CB(skb)->length = length;
832 L2TP_SKB_CB(skb)->expires = jiffies +
833 (session->reorder_timeout ? session->reorder_timeout : HZ);
835 /* Add packet to the session's receive queue. Reordering is done here, if
836 * enabled. Saved L2TP protocol info is stored in skb->sb[].
838 if (L2TP_SKB_CB(skb)->has_seq) {
839 if (l2tp_recv_data_seq(session, skb))
842 /* No sequence numbers. Add the skb to the tail of the
843 * reorder queue. This ensures that it will be
844 * delivered after all previous sequenced skbs.
846 skb_queue_tail(&session->reorder_q, skb);
849 /* Try to dequeue as many skbs from reorder_q as we can. */
850 l2tp_recv_dequeue(session);
855 atomic_long_inc(&session->stats.rx_errors);
859 (*session->deref)(session);
861 EXPORT_SYMBOL(l2tp_recv_common);
863 /* Drop skbs from the session's reorder_q
865 int l2tp_session_queue_purge(struct l2tp_session *session)
867 struct sk_buff *skb = NULL;
869 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
870 while ((skb = skb_dequeue(&session->reorder_q))) {
871 atomic_long_inc(&session->stats.rx_errors);
874 (*session->deref)(session);
878 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge);
880 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
881 * here. The skb is not on a list when we get here.
882 * Returns 0 if the packet was a data packet and was successfully passed on.
883 * Returns 1 if the packet was not a good data packet and could not be
884 * forwarded. All such packets are passed up to userspace to deal with.
886 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
887 int (*payload_hook)(struct sk_buff *skb))
889 struct l2tp_session *session = NULL;
890 unsigned char *ptr, *optr;
892 u32 tunnel_id, session_id;
896 /* UDP has verifed checksum */
898 /* UDP always verifies the packet length. */
899 __skb_pull(skb, sizeof(struct udphdr));
902 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
903 l2tp_info(tunnel, L2TP_MSG_DATA,
904 "%s: recv short packet (len=%d)\n",
905 tunnel->name, skb->len);
909 /* Trace packet contents, if enabled */
910 if (tunnel->debug & L2TP_MSG_DATA) {
911 length = min(32u, skb->len);
912 if (!pskb_may_pull(skb, length))
915 pr_debug("%s: recv\n", tunnel->name);
916 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
919 /* Point to L2TP header */
920 optr = ptr = skb->data;
922 /* Get L2TP header flags */
923 hdrflags = ntohs(*(__be16 *) ptr);
925 /* Check protocol version */
926 version = hdrflags & L2TP_HDR_VER_MASK;
927 if (version != tunnel->version) {
928 l2tp_info(tunnel, L2TP_MSG_DATA,
929 "%s: recv protocol version mismatch: got %d expected %d\n",
930 tunnel->name, version, tunnel->version);
934 /* Get length of L2TP packet */
937 /* If type is control packet, it is handled by userspace. */
938 if (hdrflags & L2TP_HDRFLAG_T) {
939 l2tp_dbg(tunnel, L2TP_MSG_DATA,
940 "%s: recv control packet, len=%d\n",
941 tunnel->name, length);
948 if (tunnel->version == L2TP_HDR_VER_2) {
949 /* If length is present, skip it */
950 if (hdrflags & L2TP_HDRFLAG_L)
953 /* Extract tunnel and session ID */
954 tunnel_id = ntohs(*(__be16 *) ptr);
956 session_id = ntohs(*(__be16 *) ptr);
959 ptr += 2; /* skip reserved bits */
960 tunnel_id = tunnel->tunnel_id;
961 session_id = ntohl(*(__be32 *) ptr);
965 /* Find the session context */
966 session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id, true);
967 if (!session || !session->recv_skb) {
970 session->deref(session);
971 l2tp_session_dec_refcount(session);
974 /* Not found? Pass to userspace to deal with */
975 l2tp_info(tunnel, L2TP_MSG_DATA,
976 "%s: no session found (%u/%u). Passing up.\n",
977 tunnel->name, tunnel_id, session_id);
981 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
982 l2tp_session_dec_refcount(session);
987 /* Put UDP header back */
988 __skb_push(skb, sizeof(struct udphdr));
993 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
997 * >0: skb should be passed up to userspace as UDP.
999 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
1001 struct l2tp_tunnel *tunnel;
1003 tunnel = l2tp_sock_to_tunnel(sk);
1007 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
1008 tunnel->name, skb->len);
1010 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
1021 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
1023 /************************************************************************
1025 ***********************************************************************/
1027 /* Build an L2TP header for the session into the buffer provided.
1029 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
1031 struct l2tp_tunnel *tunnel = session->tunnel;
1034 u16 flags = L2TP_HDR_VER_2;
1035 u32 tunnel_id = tunnel->peer_tunnel_id;
1036 u32 session_id = session->peer_session_id;
1038 if (session->send_seq)
1039 flags |= L2TP_HDRFLAG_S;
1041 /* Setup L2TP header. */
1042 *bufp++ = htons(flags);
1043 *bufp++ = htons(tunnel_id);
1044 *bufp++ = htons(session_id);
1045 if (session->send_seq) {
1046 *bufp++ = htons(session->ns);
1049 session->ns &= 0xffff;
1050 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
1051 session->name, session->ns);
1057 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
1059 struct l2tp_tunnel *tunnel = session->tunnel;
1063 /* Setup L2TP header. The header differs slightly for UDP and
1064 * IP encapsulations. For UDP, there is 4 bytes of flags.
1066 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1067 u16 flags = L2TP_HDR_VER_3;
1068 *((__be16 *) bufp) = htons(flags);
1070 *((__be16 *) bufp) = 0;
1074 *((__be32 *) bufp) = htonl(session->peer_session_id);
1076 if (session->cookie_len) {
1077 memcpy(bufp, &session->cookie[0], session->cookie_len);
1078 bufp += session->cookie_len;
1080 if (session->l2specific_len) {
1081 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
1083 if (session->send_seq) {
1084 l2h = 0x40000000 | session->ns;
1086 session->ns &= 0xffffff;
1087 l2tp_dbg(session, L2TP_MSG_SEQ,
1088 "%s: updated ns to %u\n",
1089 session->name, session->ns);
1092 *((__be32 *) bufp) = htonl(l2h);
1094 bufp += session->l2specific_len;
1096 if (session->offset)
1097 bufp += session->offset;
1102 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1103 struct flowi *fl, size_t data_len)
1105 struct l2tp_tunnel *tunnel = session->tunnel;
1106 unsigned int len = skb->len;
1110 if (session->send_seq)
1111 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes, ns=%u\n",
1112 session->name, data_len, session->ns - 1);
1114 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes\n",
1115 session->name, data_len);
1117 if (session->debug & L2TP_MSG_DATA) {
1118 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1119 unsigned char *datap = skb->data + uhlen;
1121 pr_debug("%s: xmit\n", session->name);
1122 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
1123 datap, min_t(size_t, 32, len - uhlen));
1126 /* Queue the packet to IP for output */
1128 #if IS_ENABLED(CONFIG_IPV6)
1129 if (tunnel->sock->sk_family == PF_INET6 && !tunnel->v4mapped)
1130 error = inet6_csk_xmit(tunnel->sock, skb, NULL);
1133 error = ip_queue_xmit(tunnel->sock, skb, fl);
1137 atomic_long_inc(&tunnel->stats.tx_packets);
1138 atomic_long_add(len, &tunnel->stats.tx_bytes);
1139 atomic_long_inc(&session->stats.tx_packets);
1140 atomic_long_add(len, &session->stats.tx_bytes);
1142 atomic_long_inc(&tunnel->stats.tx_errors);
1143 atomic_long_inc(&session->stats.tx_errors);
1149 /* If caller requires the skb to have a ppp header, the header must be
1150 * inserted in the skb data before calling this function.
1152 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1154 int data_len = skb->len;
1155 struct l2tp_tunnel *tunnel = session->tunnel;
1156 struct sock *sk = tunnel->sock;
1159 struct inet_sock *inet;
1161 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1163 int ret = NET_XMIT_SUCCESS;
1165 /* Check that there's enough headroom in the skb to insert IP,
1166 * UDP and L2TP headers. If not enough, expand it to
1167 * make room. Adjust truesize.
1169 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1171 if (skb_cow_head(skb, headroom)) {
1173 return NET_XMIT_DROP;
1176 /* Setup L2TP header */
1177 session->build_header(session, __skb_push(skb, hdr_len));
1179 /* Reset skb netfilter state */
1180 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1181 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1186 if (sock_owned_by_user(sk)) {
1188 ret = NET_XMIT_DROP;
1192 /* Get routing info from the tunnel socket */
1194 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
1197 fl = &inet->cork.fl;
1198 switch (tunnel->encap) {
1199 case L2TP_ENCAPTYPE_UDP:
1200 /* Setup UDP header */
1201 __skb_push(skb, sizeof(*uh));
1202 skb_reset_transport_header(skb);
1204 uh->source = inet->inet_sport;
1205 uh->dest = inet->inet_dport;
1206 udp_len = uhlen + hdr_len + data_len;
1207 uh->len = htons(udp_len);
1209 /* Calculate UDP checksum if configured to do so */
1210 #if IS_ENABLED(CONFIG_IPV6)
1211 if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
1212 udp6_set_csum(udp_get_no_check6_tx(sk),
1213 skb, &inet6_sk(sk)->saddr,
1214 &sk->sk_v6_daddr, udp_len);
1217 udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr,
1218 inet->inet_daddr, udp_len);
1221 case L2TP_ENCAPTYPE_IP:
1225 l2tp_xmit_core(session, skb, fl, data_len);
1231 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1233 /*****************************************************************************
1234 * Tinnel and session create/destroy.
1235 *****************************************************************************/
1237 /* Tunnel socket destruct hook.
1238 * The tunnel context is deleted only when all session sockets have been
1241 static void l2tp_tunnel_destruct(struct sock *sk)
1243 struct l2tp_tunnel *tunnel = l2tp_tunnel(sk);
1244 struct l2tp_net *pn;
1249 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
1252 /* Disable udp encapsulation */
1253 switch (tunnel->encap) {
1254 case L2TP_ENCAPTYPE_UDP:
1255 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1256 (udp_sk(sk))->encap_type = 0;
1257 (udp_sk(sk))->encap_rcv = NULL;
1258 (udp_sk(sk))->encap_destroy = NULL;
1260 case L2TP_ENCAPTYPE_IP:
1264 /* Remove hooks into tunnel socket */
1265 sk->sk_destruct = tunnel->old_sk_destruct;
1266 sk->sk_user_data = NULL;
1267 tunnel->sock = NULL;
1269 /* Remove the tunnel struct from the tunnel list */
1270 pn = l2tp_pernet(tunnel->l2tp_net);
1271 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1272 list_del_rcu(&tunnel->list);
1273 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1274 atomic_dec(&l2tp_tunnel_count);
1276 l2tp_tunnel_closeall(tunnel);
1277 l2tp_tunnel_dec_refcount(tunnel);
1279 /* Call the original destructor */
1280 if (sk->sk_destruct)
1281 (*sk->sk_destruct)(sk);
1286 /* When the tunnel is closed, all the attached sessions need to go too.
1288 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1291 struct hlist_node *walk;
1292 struct hlist_node *tmp;
1293 struct l2tp_session *session;
1295 BUG_ON(tunnel == NULL);
1297 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
1300 write_lock_bh(&tunnel->hlist_lock);
1301 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1303 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1304 session = hlist_entry(walk, struct l2tp_session, hlist);
1306 l2tp_info(session, L2TP_MSG_CONTROL,
1307 "%s: closing session\n", session->name);
1309 hlist_del_init(&session->hlist);
1311 if (session->ref != NULL)
1312 (*session->ref)(session);
1314 write_unlock_bh(&tunnel->hlist_lock);
1316 __l2tp_session_unhash(session);
1317 l2tp_session_queue_purge(session);
1319 if (session->session_close != NULL)
1320 (*session->session_close)(session);
1322 if (session->deref != NULL)
1323 (*session->deref)(session);
1325 l2tp_session_dec_refcount(session);
1327 write_lock_bh(&tunnel->hlist_lock);
1329 /* Now restart from the beginning of this hash
1330 * chain. We always remove a session from the
1331 * list so we are guaranteed to make forward
1337 write_unlock_bh(&tunnel->hlist_lock);
1339 EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall);
1341 /* Tunnel socket destroy hook for UDP encapsulation */
1342 static void l2tp_udp_encap_destroy(struct sock *sk)
1344 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
1346 l2tp_tunnel_closeall(tunnel);
1351 /* Really kill the tunnel.
1352 * Come here only when all sessions have been cleared from the tunnel.
1354 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
1356 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1357 BUG_ON(tunnel->sock != NULL);
1358 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name);
1359 kfree_rcu(tunnel, rcu);
1362 /* Workqueue tunnel deletion function */
1363 static void l2tp_tunnel_del_work(struct work_struct *work)
1365 struct l2tp_tunnel *tunnel = NULL;
1366 struct socket *sock = NULL;
1367 struct sock *sk = NULL;
1369 tunnel = container_of(work, struct l2tp_tunnel, del_work);
1371 l2tp_tunnel_closeall(tunnel);
1373 sk = l2tp_tunnel_sock_lookup(tunnel);
1377 sock = sk->sk_socket;
1379 /* If the tunnel socket was created by userspace, then go through the
1380 * inet layer to shut the socket down, and let userspace close it.
1381 * Otherwise, if we created the socket directly within the kernel, use
1382 * the sk API to release it here.
1383 * In either case the tunnel resources are freed in the socket
1384 * destructor when the tunnel socket goes away.
1386 if (tunnel->fd >= 0) {
1388 inet_shutdown(sock, 2);
1391 kernel_sock_shutdown(sock, SHUT_RDWR);
1396 l2tp_tunnel_sock_put(sk);
1398 l2tp_tunnel_dec_refcount(tunnel);
1401 /* Create a socket for the tunnel, if one isn't set up by
1402 * userspace. This is used for static tunnels where there is no
1403 * managing L2TP daemon.
1405 * Since we don't want these sockets to keep a namespace alive by
1406 * themselves, we drop the socket's namespace refcount after creation.
1407 * These sockets are freed when the namespace exits using the pernet
1410 static int l2tp_tunnel_sock_create(struct net *net,
1413 struct l2tp_tunnel_cfg *cfg,
1414 struct socket **sockp)
1417 struct socket *sock = NULL;
1418 struct udp_port_cfg udp_conf;
1420 switch (cfg->encap) {
1421 case L2TP_ENCAPTYPE_UDP:
1422 memset(&udp_conf, 0, sizeof(udp_conf));
1424 #if IS_ENABLED(CONFIG_IPV6)
1425 if (cfg->local_ip6 && cfg->peer_ip6) {
1426 udp_conf.family = AF_INET6;
1427 memcpy(&udp_conf.local_ip6, cfg->local_ip6,
1428 sizeof(udp_conf.local_ip6));
1429 memcpy(&udp_conf.peer_ip6, cfg->peer_ip6,
1430 sizeof(udp_conf.peer_ip6));
1431 udp_conf.use_udp6_tx_checksums =
1432 ! cfg->udp6_zero_tx_checksums;
1433 udp_conf.use_udp6_rx_checksums =
1434 ! cfg->udp6_zero_rx_checksums;
1438 udp_conf.family = AF_INET;
1439 udp_conf.local_ip = cfg->local_ip;
1440 udp_conf.peer_ip = cfg->peer_ip;
1441 udp_conf.use_udp_checksums = cfg->use_udp_checksums;
1444 udp_conf.local_udp_port = htons(cfg->local_udp_port);
1445 udp_conf.peer_udp_port = htons(cfg->peer_udp_port);
1447 err = udp_sock_create(net, &udp_conf, &sock);
1453 case L2TP_ENCAPTYPE_IP:
1454 #if IS_ENABLED(CONFIG_IPV6)
1455 if (cfg->local_ip6 && cfg->peer_ip6) {
1456 struct sockaddr_l2tpip6 ip6_addr = {0};
1458 err = sock_create_kern(net, AF_INET6, SOCK_DGRAM,
1459 IPPROTO_L2TP, &sock);
1463 ip6_addr.l2tp_family = AF_INET6;
1464 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
1465 sizeof(ip6_addr.l2tp_addr));
1466 ip6_addr.l2tp_conn_id = tunnel_id;
1467 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
1472 ip6_addr.l2tp_family = AF_INET6;
1473 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
1474 sizeof(ip6_addr.l2tp_addr));
1475 ip6_addr.l2tp_conn_id = peer_tunnel_id;
1476 err = kernel_connect(sock,
1477 (struct sockaddr *) &ip6_addr,
1478 sizeof(ip6_addr), 0);
1484 struct sockaddr_l2tpip ip_addr = {0};
1486 err = sock_create_kern(net, AF_INET, SOCK_DGRAM,
1487 IPPROTO_L2TP, &sock);
1491 ip_addr.l2tp_family = AF_INET;
1492 ip_addr.l2tp_addr = cfg->local_ip;
1493 ip_addr.l2tp_conn_id = tunnel_id;
1494 err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
1499 ip_addr.l2tp_family = AF_INET;
1500 ip_addr.l2tp_addr = cfg->peer_ip;
1501 ip_addr.l2tp_conn_id = peer_tunnel_id;
1502 err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
1503 sizeof(ip_addr), 0);
1515 if ((err < 0) && sock) {
1516 kernel_sock_shutdown(sock, SHUT_RDWR);
1524 static struct lock_class_key l2tp_socket_class;
1526 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)
1528 struct l2tp_tunnel *tunnel = NULL;
1530 struct socket *sock = NULL;
1531 struct sock *sk = NULL;
1532 struct l2tp_net *pn;
1533 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1535 /* Get the tunnel socket from the fd, which was opened by
1536 * the userspace L2TP daemon. If not specified, create a
1540 err = l2tp_tunnel_sock_create(net, tunnel_id, peer_tunnel_id,
1545 sock = sockfd_lookup(fd, &err);
1547 pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n",
1548 tunnel_id, fd, err);
1553 /* Reject namespace mismatches */
1554 if (!net_eq(sock_net(sock->sk), net)) {
1555 pr_err("tunl %u: netns mismatch\n", tunnel_id);
1566 /* Quick sanity checks */
1568 case L2TP_ENCAPTYPE_UDP:
1569 err = -EPROTONOSUPPORT;
1570 if (sk->sk_protocol != IPPROTO_UDP) {
1571 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1572 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1576 case L2TP_ENCAPTYPE_IP:
1577 err = -EPROTONOSUPPORT;
1578 if (sk->sk_protocol != IPPROTO_L2TP) {
1579 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1580 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1586 /* Check if this socket has already been prepped */
1587 tunnel = l2tp_tunnel(sk);
1588 if (tunnel != NULL) {
1589 /* This socket has already been prepped */
1594 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1595 if (tunnel == NULL) {
1600 tunnel->version = version;
1601 tunnel->tunnel_id = tunnel_id;
1602 tunnel->peer_tunnel_id = peer_tunnel_id;
1603 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1605 tunnel->magic = L2TP_TUNNEL_MAGIC;
1606 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1607 rwlock_init(&tunnel->hlist_lock);
1609 /* The net we belong to */
1610 tunnel->l2tp_net = net;
1611 pn = l2tp_pernet(net);
1614 tunnel->debug = cfg->debug;
1616 #if IS_ENABLED(CONFIG_IPV6)
1617 if (sk->sk_family == PF_INET6) {
1618 struct ipv6_pinfo *np = inet6_sk(sk);
1620 if (ipv6_addr_v4mapped(&np->saddr) &&
1621 ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
1622 struct inet_sock *inet = inet_sk(sk);
1624 tunnel->v4mapped = true;
1625 inet->inet_saddr = np->saddr.s6_addr32[3];
1626 inet->inet_rcv_saddr = sk->sk_v6_rcv_saddr.s6_addr32[3];
1627 inet->inet_daddr = sk->sk_v6_daddr.s6_addr32[3];
1629 tunnel->v4mapped = false;
1634 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1635 tunnel->encap = encap;
1636 if (encap == L2TP_ENCAPTYPE_UDP) {
1637 struct udp_tunnel_sock_cfg udp_cfg = { };
1639 udp_cfg.sk_user_data = tunnel;
1640 udp_cfg.encap_type = UDP_ENCAP_L2TPINUDP;
1641 udp_cfg.encap_rcv = l2tp_udp_encap_recv;
1642 udp_cfg.encap_destroy = l2tp_udp_encap_destroy;
1644 setup_udp_tunnel_sock(net, sock, &udp_cfg);
1646 sk->sk_user_data = tunnel;
1649 /* Hook on the tunnel socket destructor so that we can cleanup
1650 * if the tunnel socket goes away.
1652 tunnel->old_sk_destruct = sk->sk_destruct;
1653 sk->sk_destruct = &l2tp_tunnel_destruct;
1656 lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock");
1658 sk->sk_allocation = GFP_ATOMIC;
1660 /* Init delete workqueue struct */
1661 INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work);
1663 /* Add tunnel to our list */
1664 INIT_LIST_HEAD(&tunnel->list);
1665 atomic_inc(&l2tp_tunnel_count);
1667 /* Bump the reference count. The tunnel context is deleted
1668 * only when this drops to zero. Must be done before list insertion
1670 l2tp_tunnel_inc_refcount(tunnel);
1671 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1672 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1673 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1680 /* If tunnel's socket was created by the kernel, it doesn't
1683 if (sock && sock->file)
1688 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1690 /* This function is used by the netlink TUNNEL_DELETE command.
1692 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1694 l2tp_tunnel_inc_refcount(tunnel);
1695 if (false == queue_work(l2tp_wq, &tunnel->del_work)) {
1696 l2tp_tunnel_dec_refcount(tunnel);
1701 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1703 /* Really kill the session.
1705 void l2tp_session_free(struct l2tp_session *session)
1707 struct l2tp_tunnel *tunnel = session->tunnel;
1709 BUG_ON(atomic_read(&session->ref_count) != 0);
1712 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1713 if (session->session_id != 0)
1714 atomic_dec(&l2tp_session_count);
1715 sock_put(tunnel->sock);
1716 session->tunnel = NULL;
1717 l2tp_tunnel_dec_refcount(tunnel);
1722 EXPORT_SYMBOL_GPL(l2tp_session_free);
1724 /* Remove an l2tp session from l2tp_core's hash lists.
1725 * Provides a tidyup interface for pseudowire code which can't just route all
1726 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close
1729 void __l2tp_session_unhash(struct l2tp_session *session)
1731 struct l2tp_tunnel *tunnel = session->tunnel;
1733 /* Remove the session from core hashes */
1735 /* Remove from the per-tunnel hash */
1736 write_lock_bh(&tunnel->hlist_lock);
1737 hlist_del_init(&session->hlist);
1738 write_unlock_bh(&tunnel->hlist_lock);
1740 /* For L2TPv3 we have a per-net hash: remove from there, too */
1741 if (tunnel->version != L2TP_HDR_VER_2) {
1742 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1743 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1744 hlist_del_init_rcu(&session->global_hlist);
1745 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1750 EXPORT_SYMBOL_GPL(__l2tp_session_unhash);
1752 /* This function is used by the netlink SESSION_DELETE command and by
1755 int l2tp_session_delete(struct l2tp_session *session)
1758 (*session->ref)(session);
1759 __l2tp_session_unhash(session);
1760 l2tp_session_queue_purge(session);
1761 if (session->session_close != NULL)
1762 (*session->session_close)(session);
1764 (*session->deref)(session);
1765 l2tp_session_dec_refcount(session);
1768 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1770 /* We come here whenever a session's send_seq, cookie_len or
1771 * l2specific_len parameters are set.
1773 void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1775 if (version == L2TP_HDR_VER_2) {
1776 session->hdr_len = 6;
1777 if (session->send_seq)
1778 session->hdr_len += 4;
1780 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1781 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1782 session->hdr_len += 4;
1786 EXPORT_SYMBOL_GPL(l2tp_session_set_header_len);
1788 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)
1790 struct l2tp_session *session;
1793 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1794 if (session != NULL) {
1795 session->magic = L2TP_SESSION_MAGIC;
1796 session->tunnel = tunnel;
1798 session->session_id = session_id;
1799 session->peer_session_id = peer_session_id;
1801 if (tunnel->version == L2TP_HDR_VER_2)
1802 session->nr_max = 0xffff;
1804 session->nr_max = 0xffffff;
1805 session->nr_window_size = session->nr_max / 2;
1806 session->nr_oos_count_max = 4;
1808 /* Use NR of first received packet */
1809 session->reorder_skip = 1;
1811 sprintf(&session->name[0], "sess %u/%u",
1812 tunnel->tunnel_id, session->session_id);
1814 skb_queue_head_init(&session->reorder_q);
1816 INIT_HLIST_NODE(&session->hlist);
1817 INIT_HLIST_NODE(&session->global_hlist);
1819 /* Inherit debug options from tunnel */
1820 session->debug = tunnel->debug;
1823 session->pwtype = cfg->pw_type;
1824 session->debug = cfg->debug;
1825 session->mtu = cfg->mtu;
1826 session->mru = cfg->mru;
1827 session->send_seq = cfg->send_seq;
1828 session->recv_seq = cfg->recv_seq;
1829 session->lns_mode = cfg->lns_mode;
1830 session->reorder_timeout = cfg->reorder_timeout;
1831 session->offset = cfg->offset;
1832 session->l2specific_type = cfg->l2specific_type;
1833 session->l2specific_len = cfg->l2specific_len;
1834 session->cookie_len = cfg->cookie_len;
1835 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1836 session->peer_cookie_len = cfg->peer_cookie_len;
1837 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1840 if (tunnel->version == L2TP_HDR_VER_2)
1841 session->build_header = l2tp_build_l2tpv2_header;
1843 session->build_header = l2tp_build_l2tpv3_header;
1845 l2tp_session_set_header_len(session, tunnel->version);
1847 err = l2tp_session_add_to_tunnel(tunnel, session);
1851 return ERR_PTR(err);
1854 /* Bump the reference count. The session context is deleted
1855 * only when this drops to zero.
1857 l2tp_session_inc_refcount(session);
1858 l2tp_tunnel_inc_refcount(tunnel);
1860 /* Ensure tunnel socket isn't deleted */
1861 sock_hold(tunnel->sock);
1863 /* Ignore management session in session count value */
1864 if (session->session_id != 0)
1865 atomic_inc(&l2tp_session_count);
1870 return ERR_PTR(-ENOMEM);
1872 EXPORT_SYMBOL_GPL(l2tp_session_create);
1874 /*****************************************************************************
1876 *****************************************************************************/
1878 static __net_init int l2tp_init_net(struct net *net)
1880 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1883 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1884 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1886 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1887 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1889 spin_lock_init(&pn->l2tp_session_hlist_lock);
1894 static __net_exit void l2tp_exit_net(struct net *net)
1896 struct l2tp_net *pn = l2tp_pernet(net);
1897 struct l2tp_tunnel *tunnel = NULL;
1900 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
1901 (void)l2tp_tunnel_delete(tunnel);
1903 rcu_read_unlock_bh();
1905 flush_workqueue(l2tp_wq);
1909 static struct pernet_operations l2tp_net_ops = {
1910 .init = l2tp_init_net,
1911 .exit = l2tp_exit_net,
1913 .size = sizeof(struct l2tp_net),
1916 static int __init l2tp_init(void)
1920 rc = register_pernet_device(&l2tp_net_ops);
1924 l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0);
1926 pr_err("alloc_workqueue failed\n");
1927 unregister_pernet_device(&l2tp_net_ops);
1932 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
1938 static void __exit l2tp_exit(void)
1940 unregister_pernet_device(&l2tp_net_ops);
1942 destroy_workqueue(l2tp_wq);
1947 module_init(l2tp_init);
1948 module_exit(l2tp_exit);
1950 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1951 MODULE_DESCRIPTION("L2TP core");
1952 MODULE_LICENSE("GPL");
1953 MODULE_VERSION(L2TP_DRV_VERSION);