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_MAX 14
88 /* Default trace flags */
89 #define L2TP_DEFAULT_DEBUG_FLAGS 0
91 /* Private data stored for received packets in the skb.
97 unsigned long expires;
100 #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
102 static struct workqueue_struct *l2tp_wq;
104 /* per-net private data for this module */
105 static unsigned int l2tp_net_id;
107 struct list_head l2tp_tunnel_list;
108 spinlock_t l2tp_tunnel_list_lock;
109 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
110 spinlock_t l2tp_session_hlist_lock;
113 #if IS_ENABLED(CONFIG_IPV6)
114 static bool l2tp_sk_is_v6(struct sock *sk)
116 return sk->sk_family == PF_INET6 &&
117 !ipv6_addr_v4mapped(&sk->sk_v6_daddr);
121 static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk)
123 return sk->sk_user_data;
126 static inline struct l2tp_net *l2tp_pernet(const struct net *net)
130 return net_generic(net, l2tp_net_id);
133 /* Session hash global list for L2TPv3.
134 * The session_id SHOULD be random according to RFC3931, but several
135 * L2TP implementations use incrementing session_ids. So we do a real
136 * hash on the session_id, rather than a simple bitmask.
138 static inline struct hlist_head *
139 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
141 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
145 /* Session hash list.
146 * The session_id SHOULD be random according to RFC2661, but several
147 * L2TP implementations (Cisco and Microsoft) use incrementing
148 * session_ids. So we do a real hash on the session_id, rather than a
151 static inline struct hlist_head *
152 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
154 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
157 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
159 sock_put(tunnel->sock);
160 /* the tunnel is freed in the socket destructor */
162 EXPORT_SYMBOL(l2tp_tunnel_free);
164 /* Lookup a tunnel. A new reference is held on the returned tunnel. */
165 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id)
167 const struct l2tp_net *pn = l2tp_pernet(net);
168 struct l2tp_tunnel *tunnel;
171 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
172 if (tunnel->tunnel_id == tunnel_id &&
173 refcount_inc_not_zero(&tunnel->ref_count)) {
174 rcu_read_unlock_bh();
179 rcu_read_unlock_bh();
183 EXPORT_SYMBOL_GPL(l2tp_tunnel_get);
185 struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth)
187 const struct l2tp_net *pn = l2tp_pernet(net);
188 struct l2tp_tunnel *tunnel;
192 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
194 refcount_inc_not_zero(&tunnel->ref_count)) {
195 rcu_read_unlock_bh();
199 rcu_read_unlock_bh();
203 EXPORT_SYMBOL_GPL(l2tp_tunnel_get_nth);
205 struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel,
208 struct hlist_head *session_list;
209 struct l2tp_session *session;
211 session_list = l2tp_session_id_hash(tunnel, session_id);
213 read_lock_bh(&tunnel->hlist_lock);
214 hlist_for_each_entry(session, session_list, hlist)
215 if (session->session_id == session_id) {
216 l2tp_session_inc_refcount(session);
217 read_unlock_bh(&tunnel->hlist_lock);
221 read_unlock_bh(&tunnel->hlist_lock);
225 EXPORT_SYMBOL_GPL(l2tp_tunnel_get_session);
227 struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id)
229 struct hlist_head *session_list;
230 struct l2tp_session *session;
232 session_list = l2tp_session_id_hash_2(l2tp_pernet(net), session_id);
235 hlist_for_each_entry_rcu(session, session_list, global_hlist)
236 if (session->session_id == session_id) {
237 l2tp_session_inc_refcount(session);
238 rcu_read_unlock_bh();
242 rcu_read_unlock_bh();
246 EXPORT_SYMBOL_GPL(l2tp_session_get);
248 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth)
251 struct l2tp_session *session;
254 read_lock_bh(&tunnel->hlist_lock);
255 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
256 hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) {
258 l2tp_session_inc_refcount(session);
259 read_unlock_bh(&tunnel->hlist_lock);
265 read_unlock_bh(&tunnel->hlist_lock);
269 EXPORT_SYMBOL_GPL(l2tp_session_get_nth);
271 /* Lookup a session by interface name.
272 * This is very inefficient but is only used by management interfaces.
274 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
277 struct l2tp_net *pn = l2tp_pernet(net);
279 struct l2tp_session *session;
282 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
283 hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) {
284 if (!strcmp(session->ifname, ifname)) {
285 l2tp_session_inc_refcount(session);
286 rcu_read_unlock_bh();
293 rcu_read_unlock_bh();
297 EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname);
299 int l2tp_session_register(struct l2tp_session *session,
300 struct l2tp_tunnel *tunnel)
302 struct l2tp_session *session_walk;
303 struct hlist_head *g_head;
304 struct hlist_head *head;
308 head = l2tp_session_id_hash(tunnel, session->session_id);
310 write_lock_bh(&tunnel->hlist_lock);
311 if (!tunnel->acpt_newsess) {
316 hlist_for_each_entry(session_walk, head, hlist)
317 if (session_walk->session_id == session->session_id) {
322 if (tunnel->version == L2TP_HDR_VER_3) {
323 pn = l2tp_pernet(tunnel->l2tp_net);
324 g_head = l2tp_session_id_hash_2(pn, session->session_id);
326 spin_lock_bh(&pn->l2tp_session_hlist_lock);
328 /* IP encap expects session IDs to be globally unique, while
331 hlist_for_each_entry(session_walk, g_head, global_hlist)
332 if (session_walk->session_id == session->session_id &&
333 (session_walk->tunnel->encap == L2TP_ENCAPTYPE_IP ||
334 tunnel->encap == L2TP_ENCAPTYPE_IP)) {
336 goto err_tlock_pnlock;
339 l2tp_tunnel_inc_refcount(tunnel);
340 hlist_add_head_rcu(&session->global_hlist, g_head);
342 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
344 l2tp_tunnel_inc_refcount(tunnel);
347 hlist_add_head(&session->hlist, head);
348 write_unlock_bh(&tunnel->hlist_lock);
353 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
355 write_unlock_bh(&tunnel->hlist_lock);
359 EXPORT_SYMBOL_GPL(l2tp_session_register);
361 /*****************************************************************************
362 * Receive data handling
363 *****************************************************************************/
365 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
368 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
370 struct sk_buff *skbp;
372 u32 ns = L2TP_SKB_CB(skb)->ns;
374 spin_lock_bh(&session->reorder_q.lock);
375 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
376 if (L2TP_SKB_CB(skbp)->ns > ns) {
377 __skb_queue_before(&session->reorder_q, skbp, skb);
378 l2tp_dbg(session, L2TP_MSG_SEQ,
379 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
380 session->name, ns, L2TP_SKB_CB(skbp)->ns,
381 skb_queue_len(&session->reorder_q));
382 atomic_long_inc(&session->stats.rx_oos_packets);
387 __skb_queue_tail(&session->reorder_q, skb);
390 spin_unlock_bh(&session->reorder_q.lock);
393 /* Dequeue a single skb.
395 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
397 struct l2tp_tunnel *tunnel = session->tunnel;
398 int length = L2TP_SKB_CB(skb)->length;
400 /* We're about to requeue the skb, so return resources
401 * to its current owner (a socket receive buffer).
405 atomic_long_inc(&tunnel->stats.rx_packets);
406 atomic_long_add(length, &tunnel->stats.rx_bytes);
407 atomic_long_inc(&session->stats.rx_packets);
408 atomic_long_add(length, &session->stats.rx_bytes);
410 if (L2TP_SKB_CB(skb)->has_seq) {
413 session->nr &= session->nr_max;
415 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
416 session->name, session->nr);
419 /* call private receive handler */
420 if (session->recv_skb != NULL)
421 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
426 /* Dequeue skbs from the session's reorder_q, subject to packet order.
427 * Skbs that have been in the queue for too long are simply discarded.
429 static void l2tp_recv_dequeue(struct l2tp_session *session)
434 /* If the pkt at the head of the queue has the nr that we
435 * expect to send up next, dequeue it and any other
436 * in-sequence packets behind it.
439 spin_lock_bh(&session->reorder_q.lock);
440 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
441 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
442 atomic_long_inc(&session->stats.rx_seq_discards);
443 atomic_long_inc(&session->stats.rx_errors);
444 l2tp_dbg(session, L2TP_MSG_SEQ,
445 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
446 session->name, L2TP_SKB_CB(skb)->ns,
447 L2TP_SKB_CB(skb)->length, session->nr,
448 skb_queue_len(&session->reorder_q));
449 session->reorder_skip = 1;
450 __skb_unlink(skb, &session->reorder_q);
455 if (L2TP_SKB_CB(skb)->has_seq) {
456 if (session->reorder_skip) {
457 l2tp_dbg(session, L2TP_MSG_SEQ,
458 "%s: advancing nr to next pkt: %u -> %u",
459 session->name, session->nr,
460 L2TP_SKB_CB(skb)->ns);
461 session->reorder_skip = 0;
462 session->nr = L2TP_SKB_CB(skb)->ns;
464 if (L2TP_SKB_CB(skb)->ns != session->nr) {
465 l2tp_dbg(session, L2TP_MSG_SEQ,
466 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
467 session->name, L2TP_SKB_CB(skb)->ns,
468 L2TP_SKB_CB(skb)->length, session->nr,
469 skb_queue_len(&session->reorder_q));
473 __skb_unlink(skb, &session->reorder_q);
475 /* Process the skb. We release the queue lock while we
476 * do so to let other contexts process the queue.
478 spin_unlock_bh(&session->reorder_q.lock);
479 l2tp_recv_dequeue_skb(session, skb);
484 spin_unlock_bh(&session->reorder_q.lock);
487 static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
491 if (nr >= session->nr)
492 nws = nr - session->nr;
494 nws = (session->nr_max + 1) - (session->nr - nr);
496 return nws < session->nr_window_size;
499 /* If packet has sequence numbers, queue it if acceptable. Returns 0 if
500 * acceptable, else non-zero.
502 static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb)
504 if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) {
505 /* Packet sequence number is outside allowed window.
508 l2tp_dbg(session, L2TP_MSG_SEQ,
509 "%s: pkt %u len %d discarded, outside window, nr=%u\n",
510 session->name, L2TP_SKB_CB(skb)->ns,
511 L2TP_SKB_CB(skb)->length, session->nr);
515 if (session->reorder_timeout != 0) {
516 /* Packet reordering enabled. Add skb to session's
517 * reorder queue, in order of ns.
519 l2tp_recv_queue_skb(session, skb);
523 /* Packet reordering disabled. Discard out-of-sequence packets, while
524 * tracking the number if in-sequence packets after the first OOS packet
525 * is seen. After nr_oos_count_max in-sequence packets, reset the
526 * sequence number to re-enable packet reception.
528 if (L2TP_SKB_CB(skb)->ns == session->nr) {
529 skb_queue_tail(&session->reorder_q, skb);
531 u32 nr_oos = L2TP_SKB_CB(skb)->ns;
532 u32 nr_next = (session->nr_oos + 1) & session->nr_max;
534 if (nr_oos == nr_next)
535 session->nr_oos_count++;
537 session->nr_oos_count = 0;
539 session->nr_oos = nr_oos;
540 if (session->nr_oos_count > session->nr_oos_count_max) {
541 session->reorder_skip = 1;
542 l2tp_dbg(session, L2TP_MSG_SEQ,
543 "%s: %d oos packets received. Resetting sequence numbers\n",
544 session->name, session->nr_oos_count);
546 if (!session->reorder_skip) {
547 atomic_long_inc(&session->stats.rx_seq_discards);
548 l2tp_dbg(session, L2TP_MSG_SEQ,
549 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
550 session->name, L2TP_SKB_CB(skb)->ns,
551 L2TP_SKB_CB(skb)->length, session->nr,
552 skb_queue_len(&session->reorder_q));
555 skb_queue_tail(&session->reorder_q, skb);
565 /* Do receive processing of L2TP data frames. We handle both L2TPv2
566 * and L2TPv3 data frames here.
568 * L2TPv2 Data Message Header
571 * 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
572 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
573 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
574 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
575 * | Tunnel ID | Session ID |
576 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
577 * | Ns (opt) | Nr (opt) |
578 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
579 * | Offset Size (opt) | Offset pad... (opt)
580 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
582 * Data frames are marked by T=0. All other fields are the same as
583 * those in L2TP control frames.
585 * L2TPv3 Data Message Header
587 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
588 * | L2TP Session Header |
589 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
590 * | L2-Specific Sublayer |
591 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
592 * | Tunnel Payload ...
593 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
595 * L2TPv3 Session Header Over IP
598 * 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
599 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
601 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
602 * | Cookie (optional, maximum 64 bits)...
603 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
605 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
607 * L2TPv3 L2-Specific Sublayer Format
610 * 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
611 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
612 * |x|S|x|x|x|x|x|x| Sequence Number |
613 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
615 * Cookie value and sublayer format are negotiated with the peer when
616 * the session is set up. Unlike L2TPv2, we do not need to parse the
617 * packet header to determine if optional fields are present.
619 * Caller must already have parsed the frame and determined that it is
620 * a data (not control) frame before coming here. Fields up to the
621 * session-id have already been parsed and ptr points to the data
622 * after the session-id.
624 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
625 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
628 struct l2tp_tunnel *tunnel = session->tunnel;
632 /* Parse and check optional cookie */
633 if (session->peer_cookie_len > 0) {
634 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
635 l2tp_info(tunnel, L2TP_MSG_DATA,
636 "%s: cookie mismatch (%u/%u). Discarding.\n",
637 tunnel->name, tunnel->tunnel_id,
638 session->session_id);
639 atomic_long_inc(&session->stats.rx_cookie_discards);
642 ptr += session->peer_cookie_len;
645 /* Handle the optional sequence numbers. Sequence numbers are
646 * in different places for L2TPv2 and L2TPv3.
648 * If we are the LAC, enable/disable sequence numbers under
649 * the control of the LNS. If no sequence numbers present but
650 * we were expecting them, discard frame.
653 L2TP_SKB_CB(skb)->has_seq = 0;
654 if (tunnel->version == L2TP_HDR_VER_2) {
655 if (hdrflags & L2TP_HDRFLAG_S) {
656 ns = ntohs(*(__be16 *) ptr);
658 nr = ntohs(*(__be16 *) ptr);
661 /* Store L2TP info in the skb */
662 L2TP_SKB_CB(skb)->ns = ns;
663 L2TP_SKB_CB(skb)->has_seq = 1;
665 l2tp_dbg(session, L2TP_MSG_SEQ,
666 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
667 session->name, ns, nr, session->nr);
669 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
670 u32 l2h = ntohl(*(__be32 *) ptr);
672 if (l2h & 0x40000000) {
673 ns = l2h & 0x00ffffff;
675 /* Store L2TP info in the skb */
676 L2TP_SKB_CB(skb)->ns = ns;
677 L2TP_SKB_CB(skb)->has_seq = 1;
679 l2tp_dbg(session, L2TP_MSG_SEQ,
680 "%s: recv data ns=%u, session nr=%u\n",
681 session->name, ns, session->nr);
686 if (L2TP_SKB_CB(skb)->has_seq) {
687 /* Received a packet with sequence numbers. If we're the LNS,
688 * check if we sre sending sequence numbers and if not,
691 if ((!session->lns_mode) && (!session->send_seq)) {
692 l2tp_info(session, L2TP_MSG_SEQ,
693 "%s: requested to enable seq numbers by LNS\n",
695 session->send_seq = 1;
696 l2tp_session_set_header_len(session, tunnel->version);
699 /* No sequence numbers.
700 * If user has configured mandatory sequence numbers, discard.
702 if (session->recv_seq) {
703 l2tp_warn(session, L2TP_MSG_SEQ,
704 "%s: recv data has no seq numbers when required. Discarding.\n",
706 atomic_long_inc(&session->stats.rx_seq_discards);
710 /* If we're the LAC and we're sending sequence numbers, the
711 * LNS has requested that we no longer send sequence numbers.
712 * If we're the LNS and we're sending sequence numbers, the
713 * LAC is broken. Discard the frame.
715 if ((!session->lns_mode) && (session->send_seq)) {
716 l2tp_info(session, L2TP_MSG_SEQ,
717 "%s: requested to disable seq numbers by LNS\n",
719 session->send_seq = 0;
720 l2tp_session_set_header_len(session, tunnel->version);
721 } else if (session->send_seq) {
722 l2tp_warn(session, L2TP_MSG_SEQ,
723 "%s: recv data has no seq numbers when required. Discarding.\n",
725 atomic_long_inc(&session->stats.rx_seq_discards);
730 /* Session data offset is defined only for L2TPv2 and is
731 * indicated by an optional 16-bit value in the header.
733 if (tunnel->version == L2TP_HDR_VER_2) {
734 /* If offset bit set, skip it. */
735 if (hdrflags & L2TP_HDRFLAG_O) {
736 offset = ntohs(*(__be16 *)ptr);
742 if (!pskb_may_pull(skb, offset))
745 __skb_pull(skb, offset);
747 /* Prepare skb for adding to the session's reorder_q. Hold
748 * packets for max reorder_timeout or 1 second if not
751 L2TP_SKB_CB(skb)->length = length;
752 L2TP_SKB_CB(skb)->expires = jiffies +
753 (session->reorder_timeout ? session->reorder_timeout : HZ);
755 /* Add packet to the session's receive queue. Reordering is done here, if
756 * enabled. Saved L2TP protocol info is stored in skb->sb[].
758 if (L2TP_SKB_CB(skb)->has_seq) {
759 if (l2tp_recv_data_seq(session, skb))
762 /* No sequence numbers. Add the skb to the tail of the
763 * reorder queue. This ensures that it will be
764 * delivered after all previous sequenced skbs.
766 skb_queue_tail(&session->reorder_q, skb);
769 /* Try to dequeue as many skbs from reorder_q as we can. */
770 l2tp_recv_dequeue(session);
775 atomic_long_inc(&session->stats.rx_errors);
778 EXPORT_SYMBOL(l2tp_recv_common);
780 /* Drop skbs from the session's reorder_q
782 static int l2tp_session_queue_purge(struct l2tp_session *session)
784 struct sk_buff *skb = NULL;
786 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
787 while ((skb = skb_dequeue(&session->reorder_q))) {
788 atomic_long_inc(&session->stats.rx_errors);
794 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
795 * here. The skb is not on a list when we get here.
796 * Returns 0 if the packet was a data packet and was successfully passed on.
797 * Returns 1 if the packet was not a good data packet and could not be
798 * forwarded. All such packets are passed up to userspace to deal with.
800 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb)
802 struct l2tp_session *session = NULL;
803 unsigned char *ptr, *optr;
805 u32 tunnel_id, session_id;
809 /* UDP has verifed checksum */
811 /* UDP always verifies the packet length. */
812 __skb_pull(skb, sizeof(struct udphdr));
815 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_MAX)) {
816 l2tp_info(tunnel, L2TP_MSG_DATA,
817 "%s: recv short packet (len=%d)\n",
818 tunnel->name, skb->len);
822 /* Trace packet contents, if enabled */
823 if (tunnel->debug & L2TP_MSG_DATA) {
824 length = min(32u, skb->len);
825 if (!pskb_may_pull(skb, length))
828 pr_debug("%s: recv\n", tunnel->name);
829 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
832 /* Point to L2TP header */
833 optr = ptr = skb->data;
835 /* Get L2TP header flags */
836 hdrflags = ntohs(*(__be16 *) ptr);
838 /* Check protocol version */
839 version = hdrflags & L2TP_HDR_VER_MASK;
840 if (version != tunnel->version) {
841 l2tp_info(tunnel, L2TP_MSG_DATA,
842 "%s: recv protocol version mismatch: got %d expected %d\n",
843 tunnel->name, version, tunnel->version);
847 /* Get length of L2TP packet */
850 /* If type is control packet, it is handled by userspace. */
851 if (hdrflags & L2TP_HDRFLAG_T) {
852 l2tp_dbg(tunnel, L2TP_MSG_DATA,
853 "%s: recv control packet, len=%d\n",
854 tunnel->name, length);
861 if (tunnel->version == L2TP_HDR_VER_2) {
862 /* If length is present, skip it */
863 if (hdrflags & L2TP_HDRFLAG_L)
866 /* Extract tunnel and session ID */
867 tunnel_id = ntohs(*(__be16 *) ptr);
869 session_id = ntohs(*(__be16 *) ptr);
872 ptr += 2; /* skip reserved bits */
873 tunnel_id = tunnel->tunnel_id;
874 session_id = ntohl(*(__be32 *) ptr);
878 /* Find the session context */
879 session = l2tp_tunnel_get_session(tunnel, session_id);
880 if (!session || !session->recv_skb) {
882 l2tp_session_dec_refcount(session);
884 /* Not found? Pass to userspace to deal with */
885 l2tp_info(tunnel, L2TP_MSG_DATA,
886 "%s: no session found (%u/%u). Passing up.\n",
887 tunnel->name, tunnel_id, session_id);
891 if (tunnel->version == L2TP_HDR_VER_3 &&
892 l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) {
893 l2tp_session_dec_refcount(session);
897 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length);
898 l2tp_session_dec_refcount(session);
903 /* Put UDP header back */
904 __skb_push(skb, sizeof(struct udphdr));
909 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
913 * >0: skb should be passed up to userspace as UDP.
915 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
917 struct l2tp_tunnel *tunnel;
919 tunnel = rcu_dereference_sk_user_data(sk);
923 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
924 tunnel->name, skb->len);
926 if (l2tp_udp_recv_core(tunnel, skb))
934 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
936 /************************************************************************
938 ***********************************************************************/
940 /* Build an L2TP header for the session into the buffer provided.
942 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
944 struct l2tp_tunnel *tunnel = session->tunnel;
947 u16 flags = L2TP_HDR_VER_2;
948 u32 tunnel_id = tunnel->peer_tunnel_id;
949 u32 session_id = session->peer_session_id;
951 if (session->send_seq)
952 flags |= L2TP_HDRFLAG_S;
954 /* Setup L2TP header. */
955 *bufp++ = htons(flags);
956 *bufp++ = htons(tunnel_id);
957 *bufp++ = htons(session_id);
958 if (session->send_seq) {
959 *bufp++ = htons(session->ns);
962 session->ns &= 0xffff;
963 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
964 session->name, session->ns);
970 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
972 struct l2tp_tunnel *tunnel = session->tunnel;
976 /* Setup L2TP header. The header differs slightly for UDP and
977 * IP encapsulations. For UDP, there is 4 bytes of flags.
979 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
980 u16 flags = L2TP_HDR_VER_3;
981 *((__be16 *) bufp) = htons(flags);
983 *((__be16 *) bufp) = 0;
987 *((__be32 *) bufp) = htonl(session->peer_session_id);
989 if (session->cookie_len) {
990 memcpy(bufp, &session->cookie[0], session->cookie_len);
991 bufp += session->cookie_len;
993 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
996 if (session->send_seq) {
997 l2h = 0x40000000 | session->ns;
999 session->ns &= 0xffffff;
1000 l2tp_dbg(session, L2TP_MSG_SEQ,
1001 "%s: updated ns to %u\n",
1002 session->name, session->ns);
1005 *((__be32 *)bufp) = htonl(l2h);
1012 static void l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1013 struct flowi *fl, size_t data_len)
1015 struct l2tp_tunnel *tunnel = session->tunnel;
1016 unsigned int len = skb->len;
1020 if (session->send_seq)
1021 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes, ns=%u\n",
1022 session->name, data_len, session->ns - 1);
1024 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes\n",
1025 session->name, data_len);
1027 if (session->debug & L2TP_MSG_DATA) {
1028 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1029 unsigned char *datap = skb->data + uhlen;
1031 pr_debug("%s: xmit\n", session->name);
1032 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
1033 datap, min_t(size_t, 32, len - uhlen));
1036 /* Queue the packet to IP for output */
1039 #if IS_ENABLED(CONFIG_IPV6)
1040 if (l2tp_sk_is_v6(tunnel->sock))
1041 error = inet6_csk_xmit(tunnel->sock, skb, NULL);
1044 error = ip_queue_xmit(tunnel->sock, skb, fl);
1048 atomic_long_inc(&tunnel->stats.tx_packets);
1049 atomic_long_add(len, &tunnel->stats.tx_bytes);
1050 atomic_long_inc(&session->stats.tx_packets);
1051 atomic_long_add(len, &session->stats.tx_bytes);
1053 atomic_long_inc(&tunnel->stats.tx_errors);
1054 atomic_long_inc(&session->stats.tx_errors);
1058 /* If caller requires the skb to have a ppp header, the header must be
1059 * inserted in the skb data before calling this function.
1061 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1063 int data_len = skb->len;
1064 struct l2tp_tunnel *tunnel = session->tunnel;
1065 struct sock *sk = tunnel->sock;
1068 struct inet_sock *inet;
1070 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1072 int ret = NET_XMIT_SUCCESS;
1074 /* Check that there's enough headroom in the skb to insert IP,
1075 * UDP and L2TP headers. If not enough, expand it to
1076 * make room. Adjust truesize.
1078 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1080 if (skb_cow_head(skb, headroom)) {
1082 return NET_XMIT_DROP;
1085 /* Setup L2TP header */
1086 session->build_header(session, __skb_push(skb, hdr_len));
1088 /* Reset skb netfilter state */
1089 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1090 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1095 if (sock_owned_by_user(sk)) {
1097 ret = NET_XMIT_DROP;
1101 /* The user-space may change the connection status for the user-space
1102 * provided socket at run time: we must check it under the socket lock
1104 if (tunnel->fd >= 0 && sk->sk_state != TCP_ESTABLISHED) {
1106 ret = NET_XMIT_DROP;
1111 fl = &inet->cork.fl;
1112 switch (tunnel->encap) {
1113 case L2TP_ENCAPTYPE_UDP:
1114 /* Setup UDP header */
1115 __skb_push(skb, sizeof(*uh));
1116 skb_reset_transport_header(skb);
1118 uh->source = inet->inet_sport;
1119 uh->dest = inet->inet_dport;
1120 udp_len = uhlen + hdr_len + data_len;
1121 uh->len = htons(udp_len);
1123 /* Calculate UDP checksum if configured to do so */
1124 #if IS_ENABLED(CONFIG_IPV6)
1125 if (l2tp_sk_is_v6(sk))
1126 udp6_set_csum(udp_get_no_check6_tx(sk),
1127 skb, &inet6_sk(sk)->saddr,
1128 &sk->sk_v6_daddr, udp_len);
1131 udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr,
1132 inet->inet_daddr, udp_len);
1135 case L2TP_ENCAPTYPE_IP:
1139 l2tp_xmit_core(session, skb, fl, data_len);
1145 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1147 /*****************************************************************************
1148 * Tinnel and session create/destroy.
1149 *****************************************************************************/
1151 /* Tunnel socket destruct hook.
1152 * The tunnel context is deleted only when all session sockets have been
1155 static void l2tp_tunnel_destruct(struct sock *sk)
1157 struct l2tp_tunnel *tunnel = l2tp_tunnel(sk);
1162 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
1164 /* Disable udp encapsulation */
1165 switch (tunnel->encap) {
1166 case L2TP_ENCAPTYPE_UDP:
1167 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1168 (udp_sk(sk))->encap_type = 0;
1169 (udp_sk(sk))->encap_rcv = NULL;
1170 (udp_sk(sk))->encap_destroy = NULL;
1172 case L2TP_ENCAPTYPE_IP:
1176 /* Remove hooks into tunnel socket */
1177 sk->sk_destruct = tunnel->old_sk_destruct;
1178 sk->sk_user_data = NULL;
1180 /* Call the original destructor */
1181 if (sk->sk_destruct)
1182 (*sk->sk_destruct)(sk);
1184 kfree_rcu(tunnel, rcu);
1189 /* When the tunnel is closed, all the attached sessions need to go too.
1191 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1194 struct hlist_node *walk;
1195 struct hlist_node *tmp;
1196 struct l2tp_session *session;
1198 BUG_ON(tunnel == NULL);
1200 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
1203 write_lock_bh(&tunnel->hlist_lock);
1204 tunnel->acpt_newsess = false;
1205 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1207 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1208 session = hlist_entry(walk, struct l2tp_session, hlist);
1210 l2tp_info(session, L2TP_MSG_CONTROL,
1211 "%s: closing session\n", session->name);
1213 hlist_del_init(&session->hlist);
1215 if (test_and_set_bit(0, &session->dead))
1218 write_unlock_bh(&tunnel->hlist_lock);
1220 __l2tp_session_unhash(session);
1221 l2tp_session_queue_purge(session);
1223 if (session->session_close != NULL)
1224 (*session->session_close)(session);
1226 l2tp_session_dec_refcount(session);
1228 write_lock_bh(&tunnel->hlist_lock);
1230 /* Now restart from the beginning of this hash
1231 * chain. We always remove a session from the
1232 * list so we are guaranteed to make forward
1238 write_unlock_bh(&tunnel->hlist_lock);
1241 /* Tunnel socket destroy hook for UDP encapsulation */
1242 static void l2tp_udp_encap_destroy(struct sock *sk)
1244 struct l2tp_tunnel *tunnel = l2tp_tunnel(sk);
1247 l2tp_tunnel_delete(tunnel);
1250 /* Workqueue tunnel deletion function */
1251 static void l2tp_tunnel_del_work(struct work_struct *work)
1253 struct l2tp_tunnel *tunnel = container_of(work, struct l2tp_tunnel,
1255 struct sock *sk = tunnel->sock;
1256 struct socket *sock = sk->sk_socket;
1257 struct l2tp_net *pn;
1259 l2tp_tunnel_closeall(tunnel);
1261 /* If the tunnel socket was created within the kernel, use
1262 * the sk API to release it here.
1264 if (tunnel->fd < 0) {
1266 kernel_sock_shutdown(sock, SHUT_RDWR);
1271 /* Remove the tunnel struct from the tunnel list */
1272 pn = l2tp_pernet(tunnel->l2tp_net);
1273 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1274 list_del_rcu(&tunnel->list);
1275 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1277 /* drop initial ref */
1278 l2tp_tunnel_dec_refcount(tunnel);
1280 /* drop workqueue ref */
1281 l2tp_tunnel_dec_refcount(tunnel);
1284 /* Create a socket for the tunnel, if one isn't set up by
1285 * userspace. This is used for static tunnels where there is no
1286 * managing L2TP daemon.
1288 * Since we don't want these sockets to keep a namespace alive by
1289 * themselves, we drop the socket's namespace refcount after creation.
1290 * These sockets are freed when the namespace exits using the pernet
1293 static int l2tp_tunnel_sock_create(struct net *net,
1296 struct l2tp_tunnel_cfg *cfg,
1297 struct socket **sockp)
1300 struct socket *sock = NULL;
1301 struct udp_port_cfg udp_conf;
1303 switch (cfg->encap) {
1304 case L2TP_ENCAPTYPE_UDP:
1305 memset(&udp_conf, 0, sizeof(udp_conf));
1307 #if IS_ENABLED(CONFIG_IPV6)
1308 if (cfg->local_ip6 && cfg->peer_ip6) {
1309 udp_conf.family = AF_INET6;
1310 memcpy(&udp_conf.local_ip6, cfg->local_ip6,
1311 sizeof(udp_conf.local_ip6));
1312 memcpy(&udp_conf.peer_ip6, cfg->peer_ip6,
1313 sizeof(udp_conf.peer_ip6));
1314 udp_conf.use_udp6_tx_checksums =
1315 ! cfg->udp6_zero_tx_checksums;
1316 udp_conf.use_udp6_rx_checksums =
1317 ! cfg->udp6_zero_rx_checksums;
1321 udp_conf.family = AF_INET;
1322 udp_conf.local_ip = cfg->local_ip;
1323 udp_conf.peer_ip = cfg->peer_ip;
1324 udp_conf.use_udp_checksums = cfg->use_udp_checksums;
1327 udp_conf.local_udp_port = htons(cfg->local_udp_port);
1328 udp_conf.peer_udp_port = htons(cfg->peer_udp_port);
1330 err = udp_sock_create(net, &udp_conf, &sock);
1336 case L2TP_ENCAPTYPE_IP:
1337 #if IS_ENABLED(CONFIG_IPV6)
1338 if (cfg->local_ip6 && cfg->peer_ip6) {
1339 struct sockaddr_l2tpip6 ip6_addr = {0};
1341 err = sock_create_kern(net, AF_INET6, SOCK_DGRAM,
1342 IPPROTO_L2TP, &sock);
1346 ip6_addr.l2tp_family = AF_INET6;
1347 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
1348 sizeof(ip6_addr.l2tp_addr));
1349 ip6_addr.l2tp_conn_id = tunnel_id;
1350 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
1355 ip6_addr.l2tp_family = AF_INET6;
1356 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
1357 sizeof(ip6_addr.l2tp_addr));
1358 ip6_addr.l2tp_conn_id = peer_tunnel_id;
1359 err = kernel_connect(sock,
1360 (struct sockaddr *) &ip6_addr,
1361 sizeof(ip6_addr), 0);
1367 struct sockaddr_l2tpip ip_addr = {0};
1369 err = sock_create_kern(net, AF_INET, SOCK_DGRAM,
1370 IPPROTO_L2TP, &sock);
1374 ip_addr.l2tp_family = AF_INET;
1375 ip_addr.l2tp_addr = cfg->local_ip;
1376 ip_addr.l2tp_conn_id = tunnel_id;
1377 err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
1382 ip_addr.l2tp_family = AF_INET;
1383 ip_addr.l2tp_addr = cfg->peer_ip;
1384 ip_addr.l2tp_conn_id = peer_tunnel_id;
1385 err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
1386 sizeof(ip_addr), 0);
1398 if ((err < 0) && sock) {
1399 kernel_sock_shutdown(sock, SHUT_RDWR);
1407 static struct lock_class_key l2tp_socket_class;
1409 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)
1411 struct l2tp_tunnel *tunnel = NULL;
1413 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1418 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1419 if (tunnel == NULL) {
1424 tunnel->version = version;
1425 tunnel->tunnel_id = tunnel_id;
1426 tunnel->peer_tunnel_id = peer_tunnel_id;
1427 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1429 tunnel->magic = L2TP_TUNNEL_MAGIC;
1430 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1431 rwlock_init(&tunnel->hlist_lock);
1432 tunnel->acpt_newsess = true;
1435 tunnel->debug = cfg->debug;
1437 tunnel->encap = encap;
1439 refcount_set(&tunnel->ref_count, 1);
1442 /* Init delete workqueue struct */
1443 INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work);
1445 INIT_LIST_HEAD(&tunnel->list);
1454 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1456 static int l2tp_validate_socket(const struct sock *sk, const struct net *net,
1457 enum l2tp_encap_type encap)
1459 if (!net_eq(sock_net(sk), net))
1462 if (sk->sk_type != SOCK_DGRAM)
1463 return -EPROTONOSUPPORT;
1465 if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
1466 return -EPROTONOSUPPORT;
1468 if ((encap == L2TP_ENCAPTYPE_UDP && sk->sk_protocol != IPPROTO_UDP) ||
1469 (encap == L2TP_ENCAPTYPE_IP && sk->sk_protocol != IPPROTO_L2TP))
1470 return -EPROTONOSUPPORT;
1472 if (sk->sk_user_data)
1478 int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
1479 struct l2tp_tunnel_cfg *cfg)
1481 struct l2tp_tunnel *tunnel_walk;
1482 struct l2tp_net *pn;
1483 struct socket *sock;
1487 if (tunnel->fd < 0) {
1488 ret = l2tp_tunnel_sock_create(net, tunnel->tunnel_id,
1489 tunnel->peer_tunnel_id, cfg,
1494 sock = sockfd_lookup(tunnel->fd, &ret);
1498 ret = l2tp_validate_socket(sock->sk, net, tunnel->encap);
1503 tunnel->l2tp_net = net;
1504 pn = l2tp_pernet(net);
1506 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1507 list_for_each_entry(tunnel_walk, &pn->l2tp_tunnel_list, list) {
1508 if (tunnel_walk->tunnel_id == tunnel->tunnel_id) {
1509 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1515 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1516 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1522 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1523 struct udp_tunnel_sock_cfg udp_cfg = {
1524 .sk_user_data = tunnel,
1525 .encap_type = UDP_ENCAP_L2TPINUDP,
1526 .encap_rcv = l2tp_udp_encap_recv,
1527 .encap_destroy = l2tp_udp_encap_destroy,
1530 setup_udp_tunnel_sock(net, sock, &udp_cfg);
1532 sk->sk_user_data = tunnel;
1535 tunnel->old_sk_destruct = sk->sk_destruct;
1536 sk->sk_destruct = &l2tp_tunnel_destruct;
1537 lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class,
1539 sk->sk_allocation = GFP_ATOMIC;
1541 if (tunnel->fd >= 0)
1554 EXPORT_SYMBOL_GPL(l2tp_tunnel_register);
1556 /* This function is used by the netlink TUNNEL_DELETE command.
1558 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1560 if (!test_and_set_bit(0, &tunnel->dead)) {
1561 l2tp_tunnel_inc_refcount(tunnel);
1562 queue_work(l2tp_wq, &tunnel->del_work);
1565 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1567 /* Really kill the session.
1569 void l2tp_session_free(struct l2tp_session *session)
1571 struct l2tp_tunnel *tunnel = session->tunnel;
1573 BUG_ON(refcount_read(&session->ref_count) != 0);
1576 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1577 l2tp_tunnel_dec_refcount(tunnel);
1582 EXPORT_SYMBOL_GPL(l2tp_session_free);
1584 /* Remove an l2tp session from l2tp_core's hash lists.
1585 * Provides a tidyup interface for pseudowire code which can't just route all
1586 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close
1589 void __l2tp_session_unhash(struct l2tp_session *session)
1591 struct l2tp_tunnel *tunnel = session->tunnel;
1593 /* Remove the session from core hashes */
1595 /* Remove from the per-tunnel hash */
1596 write_lock_bh(&tunnel->hlist_lock);
1597 hlist_del_init(&session->hlist);
1598 write_unlock_bh(&tunnel->hlist_lock);
1600 /* For L2TPv3 we have a per-net hash: remove from there, too */
1601 if (tunnel->version != L2TP_HDR_VER_2) {
1602 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1603 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1604 hlist_del_init_rcu(&session->global_hlist);
1605 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1610 EXPORT_SYMBOL_GPL(__l2tp_session_unhash);
1612 /* This function is used by the netlink SESSION_DELETE command and by
1615 int l2tp_session_delete(struct l2tp_session *session)
1617 if (test_and_set_bit(0, &session->dead))
1620 __l2tp_session_unhash(session);
1621 l2tp_session_queue_purge(session);
1622 if (session->session_close != NULL)
1623 (*session->session_close)(session);
1625 l2tp_session_dec_refcount(session);
1629 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1631 /* We come here whenever a session's send_seq, cookie_len or
1632 * l2specific_type parameters are set.
1634 void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1636 if (version == L2TP_HDR_VER_2) {
1637 session->hdr_len = 6;
1638 if (session->send_seq)
1639 session->hdr_len += 4;
1641 session->hdr_len = 4 + session->cookie_len;
1642 session->hdr_len += l2tp_get_l2specific_len(session);
1643 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1644 session->hdr_len += 4;
1648 EXPORT_SYMBOL_GPL(l2tp_session_set_header_len);
1650 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)
1652 struct l2tp_session *session;
1654 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1655 if (session != NULL) {
1656 session->magic = L2TP_SESSION_MAGIC;
1657 session->tunnel = tunnel;
1659 session->session_id = session_id;
1660 session->peer_session_id = peer_session_id;
1662 if (tunnel->version == L2TP_HDR_VER_2)
1663 session->nr_max = 0xffff;
1665 session->nr_max = 0xffffff;
1666 session->nr_window_size = session->nr_max / 2;
1667 session->nr_oos_count_max = 4;
1669 /* Use NR of first received packet */
1670 session->reorder_skip = 1;
1672 sprintf(&session->name[0], "sess %u/%u",
1673 tunnel->tunnel_id, session->session_id);
1675 skb_queue_head_init(&session->reorder_q);
1677 INIT_HLIST_NODE(&session->hlist);
1678 INIT_HLIST_NODE(&session->global_hlist);
1680 /* Inherit debug options from tunnel */
1681 session->debug = tunnel->debug;
1684 session->pwtype = cfg->pw_type;
1685 session->debug = cfg->debug;
1686 session->send_seq = cfg->send_seq;
1687 session->recv_seq = cfg->recv_seq;
1688 session->lns_mode = cfg->lns_mode;
1689 session->reorder_timeout = cfg->reorder_timeout;
1690 session->l2specific_type = cfg->l2specific_type;
1691 session->cookie_len = cfg->cookie_len;
1692 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1693 session->peer_cookie_len = cfg->peer_cookie_len;
1694 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1697 if (tunnel->version == L2TP_HDR_VER_2)
1698 session->build_header = l2tp_build_l2tpv2_header;
1700 session->build_header = l2tp_build_l2tpv3_header;
1702 l2tp_session_set_header_len(session, tunnel->version);
1704 refcount_set(&session->ref_count, 1);
1709 return ERR_PTR(-ENOMEM);
1711 EXPORT_SYMBOL_GPL(l2tp_session_create);
1713 /*****************************************************************************
1715 *****************************************************************************/
1717 static __net_init int l2tp_init_net(struct net *net)
1719 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1722 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1723 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1725 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1726 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1728 spin_lock_init(&pn->l2tp_session_hlist_lock);
1733 static __net_exit void l2tp_exit_net(struct net *net)
1735 struct l2tp_net *pn = l2tp_pernet(net);
1736 struct l2tp_tunnel *tunnel = NULL;
1740 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
1741 l2tp_tunnel_delete(tunnel);
1743 rcu_read_unlock_bh();
1746 flush_workqueue(l2tp_wq);
1749 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1750 WARN_ON_ONCE(!hlist_empty(&pn->l2tp_session_hlist[hash]));
1753 static struct pernet_operations l2tp_net_ops = {
1754 .init = l2tp_init_net,
1755 .exit = l2tp_exit_net,
1757 .size = sizeof(struct l2tp_net),
1760 static int __init l2tp_init(void)
1764 rc = register_pernet_device(&l2tp_net_ops);
1768 l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0);
1770 pr_err("alloc_workqueue failed\n");
1771 unregister_pernet_device(&l2tp_net_ops);
1776 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
1782 static void __exit l2tp_exit(void)
1784 unregister_pernet_device(&l2tp_net_ops);
1786 destroy_workqueue(l2tp_wq);
1791 module_init(l2tp_init);
1792 module_exit(l2tp_exit);
1794 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1795 MODULE_DESCRIPTION("L2TP core");
1796 MODULE_LICENSE("GPL");
1797 MODULE_VERSION(L2TP_DRV_VERSION);