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/inet_common.h>
57 #include <net/protocol.h>
58 #include <net/inet6_connection_sock.h>
59 #include <net/inet_ecn.h>
60 #include <net/ip6_route.h>
61 #include <net/ip6_checksum.h>
63 #include <asm/byteorder.h>
64 #include <linux/atomic.h>
66 #include "l2tp_core.h"
68 #define L2TP_DRV_VERSION "V2.0"
70 /* L2TP header constants */
71 #define L2TP_HDRFLAG_T 0x8000
72 #define L2TP_HDRFLAG_L 0x4000
73 #define L2TP_HDRFLAG_S 0x0800
74 #define L2TP_HDRFLAG_O 0x0200
75 #define L2TP_HDRFLAG_P 0x0100
77 #define L2TP_HDR_VER_MASK 0x000F
78 #define L2TP_HDR_VER_2 0x0002
79 #define L2TP_HDR_VER_3 0x0003
81 /* L2TPv3 default L2-specific sublayer */
82 #define L2TP_SLFLAG_S 0x40000000
83 #define L2TP_SL_SEQ_MASK 0x00ffffff
85 #define L2TP_HDR_SIZE_SEQ 10
86 #define L2TP_HDR_SIZE_NOSEQ 6
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 atomic_t l2tp_tunnel_count;
103 static atomic_t l2tp_session_count;
105 /* per-net private data for this module */
106 static unsigned int l2tp_net_id;
108 struct list_head l2tp_tunnel_list;
109 spinlock_t l2tp_tunnel_list_lock;
110 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
111 spinlock_t l2tp_session_hlist_lock;
114 static void l2tp_session_set_header_len(struct l2tp_session *session, int version);
115 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
116 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
118 static inline struct l2tp_net *l2tp_pernet(struct net *net)
122 return net_generic(net, l2tp_net_id);
126 /* Tunnel reference counts. Incremented per session that is added to
129 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
131 atomic_inc(&tunnel->ref_count);
134 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
136 if (atomic_dec_and_test(&tunnel->ref_count))
137 l2tp_tunnel_free(tunnel);
139 #ifdef L2TP_REFCNT_DEBUG
140 #define l2tp_tunnel_inc_refcount(_t) \
142 pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \
143 __func__, __LINE__, (_t)->name, \
144 atomic_read(&_t->ref_count)); \
145 l2tp_tunnel_inc_refcount_1(_t); \
147 #define l2tp_tunnel_dec_refcount(_t)
149 pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \
150 __func__, __LINE__, (_t)->name, \
151 atomic_read(&_t->ref_count)); \
152 l2tp_tunnel_dec_refcount_1(_t); \
155 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
156 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
159 /* Session hash global list for L2TPv3.
160 * The session_id SHOULD be random according to RFC3931, but several
161 * L2TP implementations use incrementing session_ids. So we do a real
162 * hash on the session_id, rather than a simple bitmask.
164 static inline struct hlist_head *
165 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
167 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
171 /* Lookup the tunnel socket, possibly involving the fs code if the socket is
172 * owned by userspace. A struct sock returned from this function must be
173 * released using l2tp_tunnel_sock_put once you're done with it.
175 struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel)
178 struct socket *sock = NULL;
179 struct sock *sk = NULL;
184 if (tunnel->fd >= 0) {
185 /* Socket is owned by userspace, who might be in the process
186 * of closing it. Look the socket up using the fd to ensure
189 sock = sockfd_lookup(tunnel->fd, &err);
193 /* Socket is owned by kernelspace */
200 EXPORT_SYMBOL_GPL(l2tp_tunnel_sock_lookup);
202 /* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */
203 void l2tp_tunnel_sock_put(struct sock *sk)
205 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
207 if (tunnel->fd >= 0) {
208 /* Socket is owned by userspace */
209 sockfd_put(sk->sk_socket);
214 EXPORT_SYMBOL_GPL(l2tp_tunnel_sock_put);
216 /* Lookup a session by id in the global session list
218 static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
220 struct l2tp_net *pn = l2tp_pernet(net);
221 struct hlist_head *session_list =
222 l2tp_session_id_hash_2(pn, session_id);
223 struct l2tp_session *session;
224 struct hlist_node *walk;
227 hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
228 if (session->session_id == session_id) {
229 rcu_read_unlock_bh();
233 rcu_read_unlock_bh();
238 /* Session hash list.
239 * The session_id SHOULD be random according to RFC2661, but several
240 * L2TP implementations (Cisco and Microsoft) use incrementing
241 * session_ids. So we do a real hash on the session_id, rather than a
244 static inline struct hlist_head *
245 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
247 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
250 /* Lookup a session by id
252 struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
254 struct hlist_head *session_list;
255 struct l2tp_session *session;
256 struct hlist_node *walk;
258 /* In L2TPv3, session_ids are unique over all tunnels and we
259 * sometimes need to look them up before we know the
263 return l2tp_session_find_2(net, session_id);
265 session_list = l2tp_session_id_hash(tunnel, session_id);
266 read_lock_bh(&tunnel->hlist_lock);
267 hlist_for_each_entry(session, walk, session_list, hlist) {
268 if (session->session_id == session_id) {
269 read_unlock_bh(&tunnel->hlist_lock);
273 read_unlock_bh(&tunnel->hlist_lock);
277 EXPORT_SYMBOL_GPL(l2tp_session_find);
279 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth)
282 struct hlist_node *walk;
283 struct l2tp_session *session;
286 read_lock_bh(&tunnel->hlist_lock);
287 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
288 hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) {
290 read_unlock_bh(&tunnel->hlist_lock);
296 read_unlock_bh(&tunnel->hlist_lock);
300 EXPORT_SYMBOL_GPL(l2tp_session_find_nth);
302 /* Lookup a session by interface name.
303 * This is very inefficient but is only used by management interfaces.
305 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname)
307 struct l2tp_net *pn = l2tp_pernet(net);
309 struct hlist_node *walk;
310 struct l2tp_session *session;
313 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
314 hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
315 if (!strcmp(session->ifname, ifname)) {
316 rcu_read_unlock_bh();
322 rcu_read_unlock_bh();
326 EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname);
328 /* Lookup a tunnel by id
330 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
332 struct l2tp_tunnel *tunnel;
333 struct l2tp_net *pn = l2tp_pernet(net);
336 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
337 if (tunnel->tunnel_id == tunnel_id) {
338 rcu_read_unlock_bh();
342 rcu_read_unlock_bh();
346 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
348 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
350 struct l2tp_net *pn = l2tp_pernet(net);
351 struct l2tp_tunnel *tunnel;
355 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
357 rcu_read_unlock_bh();
362 rcu_read_unlock_bh();
366 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
368 /*****************************************************************************
369 * Receive data handling
370 *****************************************************************************/
372 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
375 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
377 struct sk_buff *skbp;
379 u32 ns = L2TP_SKB_CB(skb)->ns;
380 struct l2tp_stats *sstats;
382 spin_lock_bh(&session->reorder_q.lock);
383 sstats = &session->stats;
384 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
385 if (L2TP_SKB_CB(skbp)->ns > ns) {
386 __skb_queue_before(&session->reorder_q, skbp, skb);
387 l2tp_dbg(session, L2TP_MSG_SEQ,
388 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
389 session->name, ns, L2TP_SKB_CB(skbp)->ns,
390 skb_queue_len(&session->reorder_q));
391 u64_stats_update_begin(&sstats->syncp);
392 sstats->rx_oos_packets++;
393 u64_stats_update_end(&sstats->syncp);
398 __skb_queue_tail(&session->reorder_q, skb);
401 spin_unlock_bh(&session->reorder_q.lock);
404 /* Dequeue a single skb.
406 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
408 struct l2tp_tunnel *tunnel = session->tunnel;
409 int length = L2TP_SKB_CB(skb)->length;
410 struct l2tp_stats *tstats, *sstats;
412 /* We're about to requeue the skb, so return resources
413 * to its current owner (a socket receive buffer).
417 tstats = &tunnel->stats;
418 u64_stats_update_begin(&tstats->syncp);
419 sstats = &session->stats;
420 u64_stats_update_begin(&sstats->syncp);
421 tstats->rx_packets++;
422 tstats->rx_bytes += length;
423 sstats->rx_packets++;
424 sstats->rx_bytes += length;
425 u64_stats_update_end(&tstats->syncp);
426 u64_stats_update_end(&sstats->syncp);
428 if (L2TP_SKB_CB(skb)->has_seq) {
431 if (tunnel->version == L2TP_HDR_VER_2)
432 session->nr &= 0xffff;
434 session->nr &= 0xffffff;
436 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
437 session->name, session->nr);
440 /* call private receive handler */
441 if (session->recv_skb != NULL)
442 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
447 (*session->deref)(session);
450 /* Dequeue skbs from the session's reorder_q, subject to packet order.
451 * Skbs that have been in the queue for too long are simply discarded.
453 static void l2tp_recv_dequeue(struct l2tp_session *session)
457 struct l2tp_stats *sstats;
459 /* If the pkt at the head of the queue has the nr that we
460 * expect to send up next, dequeue it and any other
461 * in-sequence packets behind it.
464 spin_lock_bh(&session->reorder_q.lock);
465 sstats = &session->stats;
466 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
467 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
468 u64_stats_update_begin(&sstats->syncp);
469 sstats->rx_seq_discards++;
471 u64_stats_update_end(&sstats->syncp);
472 l2tp_dbg(session, L2TP_MSG_SEQ,
473 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
474 session->name, L2TP_SKB_CB(skb)->ns,
475 L2TP_SKB_CB(skb)->length, session->nr,
476 skb_queue_len(&session->reorder_q));
477 session->reorder_skip = 1;
478 __skb_unlink(skb, &session->reorder_q);
481 (*session->deref)(session);
485 if (L2TP_SKB_CB(skb)->has_seq) {
486 if (session->reorder_skip) {
487 l2tp_dbg(session, L2TP_MSG_SEQ,
488 "%s: advancing nr to next pkt: %u -> %u",
489 session->name, session->nr,
490 L2TP_SKB_CB(skb)->ns);
491 session->reorder_skip = 0;
492 session->nr = L2TP_SKB_CB(skb)->ns;
494 if (L2TP_SKB_CB(skb)->ns != session->nr) {
495 l2tp_dbg(session, L2TP_MSG_SEQ,
496 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
497 session->name, L2TP_SKB_CB(skb)->ns,
498 L2TP_SKB_CB(skb)->length, session->nr,
499 skb_queue_len(&session->reorder_q));
503 __skb_unlink(skb, &session->reorder_q);
505 /* Process the skb. We release the queue lock while we
506 * do so to let other contexts process the queue.
508 spin_unlock_bh(&session->reorder_q.lock);
509 l2tp_recv_dequeue_skb(session, skb);
514 spin_unlock_bh(&session->reorder_q.lock);
517 static inline int l2tp_verify_udp_checksum(struct sock *sk,
520 struct udphdr *uh = udp_hdr(skb);
521 u16 ulen = ntohs(uh->len);
524 if (sk->sk_no_check || skb_csum_unnecessary(skb))
527 #if IS_ENABLED(CONFIG_IPV6)
528 if (sk->sk_family == PF_INET6) {
530 LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
533 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
534 !csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
535 &ipv6_hdr(skb)->daddr, ulen,
536 IPPROTO_UDP, skb->csum)) {
537 skb->ip_summed = CHECKSUM_UNNECESSARY;
540 skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
541 &ipv6_hdr(skb)->daddr,
542 skb->len, IPPROTO_UDP,
547 struct inet_sock *inet;
551 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr,
552 ulen, IPPROTO_UDP, 0);
554 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
555 !csum_fold(csum_add(psum, skb->csum)))
560 return __skb_checksum_complete(skb);
563 /* Do receive processing of L2TP data frames. We handle both L2TPv2
564 * and L2TPv3 data frames here.
566 * L2TPv2 Data Message Header
569 * 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
570 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
571 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
572 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
573 * | Tunnel ID | Session ID |
574 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
575 * | Ns (opt) | Nr (opt) |
576 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
577 * | Offset Size (opt) | Offset pad... (opt)
578 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
580 * Data frames are marked by T=0. All other fields are the same as
581 * those in L2TP control frames.
583 * L2TPv3 Data Message Header
585 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
586 * | L2TP Session Header |
587 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
588 * | L2-Specific Sublayer |
589 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
590 * | Tunnel Payload ...
591 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
593 * L2TPv3 Session Header Over IP
596 * 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
597 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
599 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
600 * | Cookie (optional, maximum 64 bits)...
601 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
603 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
605 * L2TPv3 L2-Specific Sublayer Format
608 * 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
609 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
610 * |x|S|x|x|x|x|x|x| Sequence Number |
611 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
613 * Cookie value, sublayer format and offset (pad) are negotiated with
614 * the peer when the session is set up. Unlike L2TPv2, we do not need
615 * to parse the packet header to determine if optional fields are
618 * Caller must already have parsed the frame and determined that it is
619 * a data (not control) frame before coming here. Fields up to the
620 * session-id have already been parsed and ptr points to the data
621 * after the session-id.
623 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
624 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
625 int length, int (*payload_hook)(struct sk_buff *skb))
627 struct l2tp_tunnel *tunnel = session->tunnel;
630 struct l2tp_stats *sstats = &session->stats;
632 /* The ref count is increased since we now hold a pointer to
633 * the session. Take care to decrement the refcnt when exiting
634 * this function from now on...
636 l2tp_session_inc_refcount(session);
638 (*session->ref)(session);
640 /* Parse and check optional cookie */
641 if (session->peer_cookie_len > 0) {
642 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
643 l2tp_info(tunnel, L2TP_MSG_DATA,
644 "%s: cookie mismatch (%u/%u). Discarding.\n",
645 tunnel->name, tunnel->tunnel_id,
646 session->session_id);
647 u64_stats_update_begin(&sstats->syncp);
648 sstats->rx_cookie_discards++;
649 u64_stats_update_end(&sstats->syncp);
652 ptr += session->peer_cookie_len;
655 /* Handle the optional sequence numbers. Sequence numbers are
656 * in different places for L2TPv2 and L2TPv3.
658 * If we are the LAC, enable/disable sequence numbers under
659 * the control of the LNS. If no sequence numbers present but
660 * we were expecting them, discard frame.
663 L2TP_SKB_CB(skb)->has_seq = 0;
664 if (tunnel->version == L2TP_HDR_VER_2) {
665 if (hdrflags & L2TP_HDRFLAG_S) {
666 ns = ntohs(*(__be16 *) ptr);
668 nr = ntohs(*(__be16 *) ptr);
671 /* Store L2TP info in the skb */
672 L2TP_SKB_CB(skb)->ns = ns;
673 L2TP_SKB_CB(skb)->has_seq = 1;
675 l2tp_dbg(session, L2TP_MSG_SEQ,
676 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
677 session->name, ns, nr, session->nr);
679 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
680 u32 l2h = ntohl(*(__be32 *) ptr);
682 if (l2h & 0x40000000) {
683 ns = l2h & 0x00ffffff;
685 /* Store L2TP info in the skb */
686 L2TP_SKB_CB(skb)->ns = ns;
687 L2TP_SKB_CB(skb)->has_seq = 1;
689 l2tp_dbg(session, L2TP_MSG_SEQ,
690 "%s: recv data ns=%u, session nr=%u\n",
691 session->name, ns, session->nr);
695 /* Advance past L2-specific header, if present */
696 ptr += session->l2specific_len;
698 if (L2TP_SKB_CB(skb)->has_seq) {
699 /* Received a packet with sequence numbers. If we're the LNS,
700 * check if we sre sending sequence numbers and if not,
703 if ((!session->lns_mode) && (!session->send_seq)) {
704 l2tp_info(session, L2TP_MSG_SEQ,
705 "%s: requested to enable seq numbers by LNS\n",
707 session->send_seq = -1;
708 l2tp_session_set_header_len(session, tunnel->version);
711 /* No sequence numbers.
712 * If user has configured mandatory sequence numbers, discard.
714 if (session->recv_seq) {
715 l2tp_warn(session, L2TP_MSG_SEQ,
716 "%s: recv data has no seq numbers when required. Discarding.\n",
718 u64_stats_update_begin(&sstats->syncp);
719 sstats->rx_seq_discards++;
720 u64_stats_update_end(&sstats->syncp);
724 /* If we're the LAC and we're sending sequence numbers, the
725 * LNS has requested that we no longer send sequence numbers.
726 * If we're the LNS and we're sending sequence numbers, the
727 * LAC is broken. Discard the frame.
729 if ((!session->lns_mode) && (session->send_seq)) {
730 l2tp_info(session, L2TP_MSG_SEQ,
731 "%s: requested to disable seq numbers by LNS\n",
733 session->send_seq = 0;
734 l2tp_session_set_header_len(session, tunnel->version);
735 } else if (session->send_seq) {
736 l2tp_warn(session, L2TP_MSG_SEQ,
737 "%s: recv data has no seq numbers when required. Discarding.\n",
739 u64_stats_update_begin(&sstats->syncp);
740 sstats->rx_seq_discards++;
741 u64_stats_update_end(&sstats->syncp);
746 /* Session data offset is handled differently for L2TPv2 and
747 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
748 * the header. For L2TPv3, the offset is negotiated using AVPs
749 * in the session setup control protocol.
751 if (tunnel->version == L2TP_HDR_VER_2) {
752 /* If offset bit set, skip it. */
753 if (hdrflags & L2TP_HDRFLAG_O) {
754 offset = ntohs(*(__be16 *)ptr);
758 ptr += session->offset;
761 if (!pskb_may_pull(skb, offset))
764 __skb_pull(skb, offset);
766 /* If caller wants to process the payload before we queue the
770 if ((*payload_hook)(skb))
773 /* Prepare skb for adding to the session's reorder_q. Hold
774 * packets for max reorder_timeout or 1 second if not
777 L2TP_SKB_CB(skb)->length = length;
778 L2TP_SKB_CB(skb)->expires = jiffies +
779 (session->reorder_timeout ? session->reorder_timeout : HZ);
781 /* Add packet to the session's receive queue. Reordering is done here, if
782 * enabled. Saved L2TP protocol info is stored in skb->sb[].
784 if (L2TP_SKB_CB(skb)->has_seq) {
785 if (session->reorder_timeout != 0) {
786 /* Packet reordering enabled. Add skb to session's
787 * reorder queue, in order of ns.
789 l2tp_recv_queue_skb(session, skb);
791 /* Packet reordering disabled. Discard out-of-sequence
794 if (L2TP_SKB_CB(skb)->ns != session->nr) {
795 u64_stats_update_begin(&sstats->syncp);
796 sstats->rx_seq_discards++;
797 u64_stats_update_end(&sstats->syncp);
798 l2tp_dbg(session, L2TP_MSG_SEQ,
799 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
800 session->name, L2TP_SKB_CB(skb)->ns,
801 L2TP_SKB_CB(skb)->length, session->nr,
802 skb_queue_len(&session->reorder_q));
805 skb_queue_tail(&session->reorder_q, skb);
808 /* No sequence numbers. Add the skb to the tail of the
809 * reorder queue. This ensures that it will be
810 * delivered after all previous sequenced skbs.
812 skb_queue_tail(&session->reorder_q, skb);
815 /* Try to dequeue as many skbs from reorder_q as we can. */
816 l2tp_recv_dequeue(session);
818 l2tp_session_dec_refcount(session);
823 u64_stats_update_begin(&sstats->syncp);
825 u64_stats_update_end(&sstats->syncp);
829 (*session->deref)(session);
831 l2tp_session_dec_refcount(session);
833 EXPORT_SYMBOL(l2tp_recv_common);
835 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
836 * here. The skb is not on a list when we get here.
837 * Returns 0 if the packet was a data packet and was successfully passed on.
838 * Returns 1 if the packet was not a good data packet and could not be
839 * forwarded. All such packets are passed up to userspace to deal with.
841 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
842 int (*payload_hook)(struct sk_buff *skb))
844 struct l2tp_session *session = NULL;
845 unsigned char *ptr, *optr;
847 u32 tunnel_id, session_id;
850 struct l2tp_stats *tstats;
852 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
853 goto discard_bad_csum;
855 /* UDP always verifies the packet length. */
856 __skb_pull(skb, sizeof(struct udphdr));
859 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
860 l2tp_info(tunnel, L2TP_MSG_DATA,
861 "%s: recv short packet (len=%d)\n",
862 tunnel->name, skb->len);
866 /* Trace packet contents, if enabled */
867 if (tunnel->debug & L2TP_MSG_DATA) {
868 length = min(32u, skb->len);
869 if (!pskb_may_pull(skb, length))
872 pr_debug("%s: recv\n", tunnel->name);
873 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
876 /* Point to L2TP header */
877 optr = ptr = skb->data;
879 /* Get L2TP header flags */
880 hdrflags = ntohs(*(__be16 *) ptr);
882 /* Check protocol version */
883 version = hdrflags & L2TP_HDR_VER_MASK;
884 if (version != tunnel->version) {
885 l2tp_info(tunnel, L2TP_MSG_DATA,
886 "%s: recv protocol version mismatch: got %d expected %d\n",
887 tunnel->name, version, tunnel->version);
891 /* Get length of L2TP packet */
894 /* If type is control packet, it is handled by userspace. */
895 if (hdrflags & L2TP_HDRFLAG_T) {
896 l2tp_dbg(tunnel, L2TP_MSG_DATA,
897 "%s: recv control packet, len=%d\n",
898 tunnel->name, length);
905 if (tunnel->version == L2TP_HDR_VER_2) {
906 /* If length is present, skip it */
907 if (hdrflags & L2TP_HDRFLAG_L)
910 /* Extract tunnel and session ID */
911 tunnel_id = ntohs(*(__be16 *) ptr);
913 session_id = ntohs(*(__be16 *) ptr);
916 ptr += 2; /* skip reserved bits */
917 tunnel_id = tunnel->tunnel_id;
918 session_id = ntohl(*(__be32 *) ptr);
922 /* Find the session context */
923 session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id);
924 if (!session || !session->recv_skb) {
925 /* Not found? Pass to userspace to deal with */
926 l2tp_info(tunnel, L2TP_MSG_DATA,
927 "%s: no session found (%u/%u). Passing up.\n",
928 tunnel->name, tunnel_id, session_id);
932 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
937 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
938 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
939 tstats = &tunnel->stats;
940 u64_stats_update_begin(&tstats->syncp);
942 u64_stats_update_end(&tstats->syncp);
948 /* Put UDP header back */
949 __skb_push(skb, sizeof(struct udphdr));
954 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
958 * >0: skb should be passed up to userspace as UDP.
960 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
962 struct l2tp_tunnel *tunnel;
964 tunnel = l2tp_sock_to_tunnel(sk);
968 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
969 tunnel->name, skb->len);
971 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
982 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
984 /************************************************************************
986 ***********************************************************************/
988 /* Build an L2TP header for the session into the buffer provided.
990 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
992 struct l2tp_tunnel *tunnel = session->tunnel;
995 u16 flags = L2TP_HDR_VER_2;
996 u32 tunnel_id = tunnel->peer_tunnel_id;
997 u32 session_id = session->peer_session_id;
999 if (session->send_seq)
1000 flags |= L2TP_HDRFLAG_S;
1002 /* Setup L2TP header. */
1003 *bufp++ = htons(flags);
1004 *bufp++ = htons(tunnel_id);
1005 *bufp++ = htons(session_id);
1006 if (session->send_seq) {
1007 *bufp++ = htons(session->ns);
1010 session->ns &= 0xffff;
1011 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
1012 session->name, session->ns);
1018 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
1020 struct l2tp_tunnel *tunnel = session->tunnel;
1024 /* Setup L2TP header. The header differs slightly for UDP and
1025 * IP encapsulations. For UDP, there is 4 bytes of flags.
1027 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1028 u16 flags = L2TP_HDR_VER_3;
1029 *((__be16 *) bufp) = htons(flags);
1031 *((__be16 *) bufp) = 0;
1035 *((__be32 *) bufp) = htonl(session->peer_session_id);
1037 if (session->cookie_len) {
1038 memcpy(bufp, &session->cookie[0], session->cookie_len);
1039 bufp += session->cookie_len;
1041 if (session->l2specific_len) {
1042 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
1044 if (session->send_seq) {
1045 l2h = 0x40000000 | session->ns;
1047 session->ns &= 0xffffff;
1048 l2tp_dbg(session, L2TP_MSG_SEQ,
1049 "%s: updated ns to %u\n",
1050 session->name, session->ns);
1053 *((__be32 *) bufp) = htonl(l2h);
1055 bufp += session->l2specific_len;
1057 if (session->offset)
1058 bufp += session->offset;
1063 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1064 struct flowi *fl, size_t data_len)
1066 struct l2tp_tunnel *tunnel = session->tunnel;
1067 unsigned int len = skb->len;
1069 struct l2tp_stats *tstats, *sstats;
1072 if (session->send_seq)
1073 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes, ns=%u\n",
1074 session->name, data_len, session->ns - 1);
1076 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes\n",
1077 session->name, data_len);
1079 if (session->debug & L2TP_MSG_DATA) {
1080 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1081 unsigned char *datap = skb->data + uhlen;
1083 pr_debug("%s: xmit\n", session->name);
1084 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
1085 datap, min_t(size_t, 32, len - uhlen));
1088 /* Queue the packet to IP for output */
1090 #if IS_ENABLED(CONFIG_IPV6)
1091 if (skb->sk->sk_family == PF_INET6)
1092 error = inet6_csk_xmit(skb, NULL);
1095 error = ip_queue_xmit(skb, fl);
1098 tstats = &tunnel->stats;
1099 u64_stats_update_begin(&tstats->syncp);
1100 sstats = &session->stats;
1101 u64_stats_update_begin(&sstats->syncp);
1103 tstats->tx_packets++;
1104 tstats->tx_bytes += len;
1105 sstats->tx_packets++;
1106 sstats->tx_bytes += len;
1108 tstats->tx_errors++;
1109 sstats->tx_errors++;
1111 u64_stats_update_end(&tstats->syncp);
1112 u64_stats_update_end(&sstats->syncp);
1117 /* Automatically called when the skb is freed.
1119 static void l2tp_sock_wfree(struct sk_buff *skb)
1124 /* For data skbs that we transmit, we associate with the tunnel socket
1125 * but don't do accounting.
1127 static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1131 skb->destructor = l2tp_sock_wfree;
1134 #if IS_ENABLED(CONFIG_IPV6)
1135 static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb,
1138 struct ipv6_pinfo *np = inet6_sk(sk);
1139 struct udphdr *uh = udp_hdr(skb);
1141 if (!skb_dst(skb) || !skb_dst(skb)->dev ||
1142 !(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) {
1143 __wsum csum = skb_checksum(skb, 0, udp_len, 0);
1144 skb->ip_summed = CHECKSUM_UNNECESSARY;
1145 uh->check = csum_ipv6_magic(&np->saddr, &np->daddr, udp_len,
1148 uh->check = CSUM_MANGLED_0;
1150 skb->ip_summed = CHECKSUM_PARTIAL;
1151 skb->csum_start = skb_transport_header(skb) - skb->head;
1152 skb->csum_offset = offsetof(struct udphdr, check);
1153 uh->check = ~csum_ipv6_magic(&np->saddr, &np->daddr,
1154 udp_len, IPPROTO_UDP, 0);
1159 /* If caller requires the skb to have a ppp header, the header must be
1160 * inserted in the skb data before calling this function.
1162 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1164 int data_len = skb->len;
1165 struct l2tp_tunnel *tunnel = session->tunnel;
1166 struct sock *sk = tunnel->sock;
1169 struct inet_sock *inet;
1174 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1176 int ret = NET_XMIT_SUCCESS;
1178 /* Check that there's enough headroom in the skb to insert IP,
1179 * UDP and L2TP headers. If not enough, expand it to
1180 * make room. Adjust truesize.
1182 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1184 old_headroom = skb_headroom(skb);
1185 if (skb_cow_head(skb, headroom)) {
1187 return NET_XMIT_DROP;
1190 new_headroom = skb_headroom(skb);
1192 skb->truesize += new_headroom - old_headroom;
1194 /* Setup L2TP header */
1195 session->build_header(session, __skb_push(skb, hdr_len));
1197 /* Reset skb netfilter state */
1198 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1199 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1204 if (sock_owned_by_user(sk)) {
1206 ret = NET_XMIT_DROP;
1210 /* Get routing info from the tunnel socket */
1212 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
1215 fl = &inet->cork.fl;
1216 switch (tunnel->encap) {
1217 case L2TP_ENCAPTYPE_UDP:
1218 /* Setup UDP header */
1219 __skb_push(skb, sizeof(*uh));
1220 skb_reset_transport_header(skb);
1222 uh->source = inet->inet_sport;
1223 uh->dest = inet->inet_dport;
1224 udp_len = uhlen + hdr_len + data_len;
1225 uh->len = htons(udp_len);
1228 /* Calculate UDP checksum if configured to do so */
1229 #if IS_ENABLED(CONFIG_IPV6)
1230 if (sk->sk_family == PF_INET6)
1231 l2tp_xmit_ipv6_csum(sk, skb, udp_len);
1234 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1235 skb->ip_summed = CHECKSUM_NONE;
1236 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1237 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1238 skb->ip_summed = CHECKSUM_COMPLETE;
1239 csum = skb_checksum(skb, 0, udp_len, 0);
1240 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1242 udp_len, IPPROTO_UDP, csum);
1244 uh->check = CSUM_MANGLED_0;
1246 skb->ip_summed = CHECKSUM_PARTIAL;
1247 skb->csum_start = skb_transport_header(skb) - skb->head;
1248 skb->csum_offset = offsetof(struct udphdr, check);
1249 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1251 udp_len, IPPROTO_UDP, 0);
1255 case L2TP_ENCAPTYPE_IP:
1259 l2tp_skb_set_owner_w(skb, sk);
1261 l2tp_xmit_core(session, skb, fl, data_len);
1267 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1269 /*****************************************************************************
1270 * Tinnel and session create/destroy.
1271 *****************************************************************************/
1273 /* Tunnel socket destruct hook.
1274 * The tunnel context is deleted only when all session sockets have been
1277 static void l2tp_tunnel_destruct(struct sock *sk)
1279 struct l2tp_tunnel *tunnel;
1281 tunnel = sk->sk_user_data;
1285 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
1287 /* Close all sessions */
1288 l2tp_tunnel_closeall(tunnel);
1290 switch (tunnel->encap) {
1291 case L2TP_ENCAPTYPE_UDP:
1292 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1293 (udp_sk(sk))->encap_type = 0;
1294 (udp_sk(sk))->encap_rcv = NULL;
1296 case L2TP_ENCAPTYPE_IP:
1300 /* Remove hooks into tunnel socket */
1301 tunnel->sock = NULL;
1302 sk->sk_destruct = tunnel->old_sk_destruct;
1303 sk->sk_user_data = NULL;
1305 /* Call the original destructor */
1306 if (sk->sk_destruct)
1307 (*sk->sk_destruct)(sk);
1309 /* We're finished with the socket */
1310 l2tp_tunnel_dec_refcount(tunnel);
1316 /* When the tunnel is closed, all the attached sessions need to go too.
1318 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1321 struct hlist_node *walk;
1322 struct hlist_node *tmp;
1323 struct l2tp_session *session;
1325 BUG_ON(tunnel == NULL);
1327 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
1330 write_lock_bh(&tunnel->hlist_lock);
1331 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1333 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1334 session = hlist_entry(walk, struct l2tp_session, hlist);
1336 l2tp_info(session, L2TP_MSG_CONTROL,
1337 "%s: closing session\n", session->name);
1339 hlist_del_init(&session->hlist);
1341 /* Since we should hold the sock lock while
1342 * doing any unbinding, we need to release the
1343 * lock we're holding before taking that lock.
1344 * Hold a reference to the sock so it doesn't
1345 * disappear as we're jumping between locks.
1347 if (session->ref != NULL)
1348 (*session->ref)(session);
1350 write_unlock_bh(&tunnel->hlist_lock);
1352 if (tunnel->version != L2TP_HDR_VER_2) {
1353 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1355 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1356 hlist_del_init_rcu(&session->global_hlist);
1357 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1361 if (session->session_close != NULL)
1362 (*session->session_close)(session);
1364 if (session->deref != NULL)
1365 (*session->deref)(session);
1367 write_lock_bh(&tunnel->hlist_lock);
1369 /* Now restart from the beginning of this hash
1370 * chain. We always remove a session from the
1371 * list so we are guaranteed to make forward
1377 write_unlock_bh(&tunnel->hlist_lock);
1380 /* Really kill the tunnel.
1381 * Come here only when all sessions have been cleared from the tunnel.
1383 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
1385 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1387 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1388 BUG_ON(tunnel->sock != NULL);
1390 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name);
1392 /* Remove from tunnel list */
1393 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1394 list_del_rcu(&tunnel->list);
1395 kfree_rcu(tunnel, rcu);
1396 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1398 atomic_dec(&l2tp_tunnel_count);
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 static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1408 struct sockaddr_in udp_addr;
1409 #if IS_ENABLED(CONFIG_IPV6)
1410 struct sockaddr_in6 udp6_addr;
1411 struct sockaddr_l2tpip6 ip6_addr;
1413 struct sockaddr_l2tpip ip_addr;
1414 struct socket *sock = NULL;
1416 switch (cfg->encap) {
1417 case L2TP_ENCAPTYPE_UDP:
1418 #if IS_ENABLED(CONFIG_IPV6)
1419 if (cfg->local_ip6 && cfg->peer_ip6) {
1420 err = sock_create(AF_INET6, SOCK_DGRAM, 0, sockp);
1426 memset(&udp6_addr, 0, sizeof(udp6_addr));
1427 udp6_addr.sin6_family = AF_INET6;
1428 memcpy(&udp6_addr.sin6_addr, cfg->local_ip6,
1429 sizeof(udp6_addr.sin6_addr));
1430 udp6_addr.sin6_port = htons(cfg->local_udp_port);
1431 err = kernel_bind(sock, (struct sockaddr *) &udp6_addr,
1436 udp6_addr.sin6_family = AF_INET6;
1437 memcpy(&udp6_addr.sin6_addr, cfg->peer_ip6,
1438 sizeof(udp6_addr.sin6_addr));
1439 udp6_addr.sin6_port = htons(cfg->peer_udp_port);
1440 err = kernel_connect(sock,
1441 (struct sockaddr *) &udp6_addr,
1442 sizeof(udp6_addr), 0);
1448 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1454 memset(&udp_addr, 0, sizeof(udp_addr));
1455 udp_addr.sin_family = AF_INET;
1456 udp_addr.sin_addr = cfg->local_ip;
1457 udp_addr.sin_port = htons(cfg->local_udp_port);
1458 err = kernel_bind(sock, (struct sockaddr *) &udp_addr,
1463 udp_addr.sin_family = AF_INET;
1464 udp_addr.sin_addr = cfg->peer_ip;
1465 udp_addr.sin_port = htons(cfg->peer_udp_port);
1466 err = kernel_connect(sock,
1467 (struct sockaddr *) &udp_addr,
1468 sizeof(udp_addr), 0);
1473 if (!cfg->use_udp_checksums)
1474 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1478 case L2TP_ENCAPTYPE_IP:
1479 #if IS_ENABLED(CONFIG_IPV6)
1480 if (cfg->local_ip6 && cfg->peer_ip6) {
1481 err = sock_create(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP,
1488 memset(&ip6_addr, 0, sizeof(ip6_addr));
1489 ip6_addr.l2tp_family = AF_INET6;
1490 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
1491 sizeof(ip6_addr.l2tp_addr));
1492 ip6_addr.l2tp_conn_id = tunnel_id;
1493 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
1498 ip6_addr.l2tp_family = AF_INET6;
1499 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
1500 sizeof(ip6_addr.l2tp_addr));
1501 ip6_addr.l2tp_conn_id = peer_tunnel_id;
1502 err = kernel_connect(sock,
1503 (struct sockaddr *) &ip6_addr,
1504 sizeof(ip6_addr), 0);
1510 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP,
1517 memset(&ip_addr, 0, sizeof(ip_addr));
1518 ip_addr.l2tp_family = AF_INET;
1519 ip_addr.l2tp_addr = cfg->local_ip;
1520 ip_addr.l2tp_conn_id = tunnel_id;
1521 err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
1526 ip_addr.l2tp_family = AF_INET;
1527 ip_addr.l2tp_addr = cfg->peer_ip;
1528 ip_addr.l2tp_conn_id = peer_tunnel_id;
1529 err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
1530 sizeof(ip_addr), 0);
1541 if ((err < 0) && sock) {
1549 static struct lock_class_key l2tp_socket_class;
1551 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)
1553 struct l2tp_tunnel *tunnel = NULL;
1555 struct socket *sock = NULL;
1556 struct sock *sk = NULL;
1557 struct l2tp_net *pn;
1558 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1560 /* Get the tunnel socket from the fd, which was opened by
1561 * the userspace L2TP daemon. If not specified, create a
1565 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1570 sock = sockfd_lookup(fd, &err);
1572 pr_err("tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1573 tunnel_id, fd, err);
1583 /* Quick sanity checks */
1585 case L2TP_ENCAPTYPE_UDP:
1586 err = -EPROTONOSUPPORT;
1587 if (sk->sk_protocol != IPPROTO_UDP) {
1588 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1589 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1593 case L2TP_ENCAPTYPE_IP:
1594 err = -EPROTONOSUPPORT;
1595 if (sk->sk_protocol != IPPROTO_L2TP) {
1596 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1597 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1603 /* Check if this socket has already been prepped */
1604 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1605 if (tunnel != NULL) {
1606 /* This socket has already been prepped */
1611 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1612 if (tunnel == NULL) {
1617 tunnel->version = version;
1618 tunnel->tunnel_id = tunnel_id;
1619 tunnel->peer_tunnel_id = peer_tunnel_id;
1620 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1622 tunnel->magic = L2TP_TUNNEL_MAGIC;
1623 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1624 rwlock_init(&tunnel->hlist_lock);
1626 /* The net we belong to */
1627 tunnel->l2tp_net = net;
1628 pn = l2tp_pernet(net);
1631 tunnel->debug = cfg->debug;
1633 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1634 tunnel->encap = encap;
1635 if (encap == L2TP_ENCAPTYPE_UDP) {
1636 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1637 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1638 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1639 #if IS_ENABLED(CONFIG_IPV6)
1640 if (sk->sk_family == PF_INET6)
1641 udpv6_encap_enable();
1647 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 /* Add tunnel to our list */
1661 INIT_LIST_HEAD(&tunnel->list);
1662 atomic_inc(&l2tp_tunnel_count);
1664 /* Bump the reference count. The tunnel context is deleted
1665 * only when this drops to zero. Must be done before list insertion
1667 l2tp_tunnel_inc_refcount(tunnel);
1668 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1669 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1670 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1677 /* If tunnel's socket was created by the kernel, it doesn't
1680 if (sock && sock->file)
1685 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1687 /* This function is used by the netlink TUNNEL_DELETE command.
1689 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1692 struct socket *sock = NULL;
1693 struct sock *sk = NULL;
1695 sk = l2tp_tunnel_sock_lookup(tunnel);
1699 sock = sk->sk_socket;
1702 /* Force the tunnel socket to close. This will eventually
1703 * cause the tunnel to be deleted via the normal socket close
1704 * mechanisms when userspace closes the tunnel socket.
1706 err = inet_shutdown(sock, 2);
1708 /* If the tunnel's socket was created by the kernel,
1709 * close the socket here since the socket was not
1710 * created by userspace.
1712 if (sock->file == NULL)
1713 err = inet_release(sock);
1715 l2tp_tunnel_sock_put(sk);
1719 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1721 /* Really kill the session.
1723 void l2tp_session_free(struct l2tp_session *session)
1725 struct l2tp_tunnel *tunnel;
1727 BUG_ON(atomic_read(&session->ref_count) != 0);
1729 tunnel = session->tunnel;
1730 if (tunnel != NULL) {
1731 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1733 /* Delete the session from the hash */
1734 write_lock_bh(&tunnel->hlist_lock);
1735 hlist_del_init(&session->hlist);
1736 write_unlock_bh(&tunnel->hlist_lock);
1738 /* Unlink from the global hash if not L2TPv2 */
1739 if (tunnel->version != L2TP_HDR_VER_2) {
1740 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1742 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1743 hlist_del_init_rcu(&session->global_hlist);
1744 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1748 if (session->session_id != 0)
1749 atomic_dec(&l2tp_session_count);
1751 sock_put(tunnel->sock);
1753 /* This will delete the tunnel context if this
1754 * is the last session on the tunnel.
1756 session->tunnel = NULL;
1757 l2tp_tunnel_dec_refcount(tunnel);
1764 EXPORT_SYMBOL_GPL(l2tp_session_free);
1766 /* This function is used by the netlink SESSION_DELETE command and by
1769 int l2tp_session_delete(struct l2tp_session *session)
1771 if (session->session_close != NULL)
1772 (*session->session_close)(session);
1774 l2tp_session_dec_refcount(session);
1778 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1781 /* We come here whenever a session's send_seq, cookie_len or
1782 * l2specific_len parameters are set.
1784 static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1786 if (version == L2TP_HDR_VER_2) {
1787 session->hdr_len = 6;
1788 if (session->send_seq)
1789 session->hdr_len += 4;
1791 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1792 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1793 session->hdr_len += 4;
1798 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)
1800 struct l2tp_session *session;
1802 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1803 if (session != NULL) {
1804 session->magic = L2TP_SESSION_MAGIC;
1805 session->tunnel = tunnel;
1807 session->session_id = session_id;
1808 session->peer_session_id = peer_session_id;
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 /* Bump the reference count. The session context is deleted
1848 * only when this drops to zero.
1850 l2tp_session_inc_refcount(session);
1851 l2tp_tunnel_inc_refcount(tunnel);
1853 /* Ensure tunnel socket isn't deleted */
1854 sock_hold(tunnel->sock);
1856 /* Add session to the tunnel's hash list */
1857 write_lock_bh(&tunnel->hlist_lock);
1858 hlist_add_head(&session->hlist,
1859 l2tp_session_id_hash(tunnel, session_id));
1860 write_unlock_bh(&tunnel->hlist_lock);
1862 /* And to the global session list if L2TPv3 */
1863 if (tunnel->version != L2TP_HDR_VER_2) {
1864 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1866 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1867 hlist_add_head_rcu(&session->global_hlist,
1868 l2tp_session_id_hash_2(pn, session_id));
1869 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1872 /* Ignore management session in session count value */
1873 if (session->session_id != 0)
1874 atomic_inc(&l2tp_session_count);
1879 EXPORT_SYMBOL_GPL(l2tp_session_create);
1881 /*****************************************************************************
1883 *****************************************************************************/
1885 static __net_init int l2tp_init_net(struct net *net)
1887 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1890 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1891 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1893 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1894 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1896 spin_lock_init(&pn->l2tp_session_hlist_lock);
1901 static struct pernet_operations l2tp_net_ops = {
1902 .init = l2tp_init_net,
1904 .size = sizeof(struct l2tp_net),
1907 static int __init l2tp_init(void)
1911 rc = register_pernet_device(&l2tp_net_ops);
1915 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
1921 static void __exit l2tp_exit(void)
1923 unregister_pernet_device(&l2tp_net_ops);
1926 module_init(l2tp_init);
1927 module_exit(l2tp_exit);
1929 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1930 MODULE_DESCRIPTION("L2TP core");
1931 MODULE_LICENSE("GPL");
1932 MODULE_VERSION(L2TP_DRV_VERSION);