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
;
104 static struct workqueue_struct
*l2tp_wq
;
106 /* per-net private data for this module */
107 static unsigned int l2tp_net_id
;
109 struct list_head l2tp_tunnel_list
;
110 spinlock_t l2tp_tunnel_list_lock
;
111 struct hlist_head l2tp_session_hlist
[L2TP_HASH_SIZE_2
];
112 spinlock_t l2tp_session_hlist_lock
;
115 static void l2tp_tunnel_free(struct l2tp_tunnel
*tunnel
);
117 static inline struct l2tp_tunnel
*l2tp_tunnel(struct sock
*sk
)
119 return sk
->sk_user_data
;
122 static inline struct l2tp_net
*l2tp_pernet(struct net
*net
)
126 return net_generic(net
, l2tp_net_id
);
129 /* Tunnel reference counts. Incremented per session that is added to
132 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel
*tunnel
)
134 atomic_inc(&tunnel
->ref_count
);
137 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel
*tunnel
)
139 if (atomic_dec_and_test(&tunnel
->ref_count
))
140 l2tp_tunnel_free(tunnel
);
142 #ifdef L2TP_REFCNT_DEBUG
143 #define l2tp_tunnel_inc_refcount(_t) \
145 pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \
146 __func__, __LINE__, (_t)->name, \
147 atomic_read(&_t->ref_count)); \
148 l2tp_tunnel_inc_refcount_1(_t); \
150 #define l2tp_tunnel_dec_refcount(_t)
152 pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \
153 __func__
, __LINE__
, (_t
)->name
, \
154 atomic_read(&_t
->ref_count
)); \
155 l2tp_tunnel_dec_refcount_1(_t
); \
158 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
159 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
162 /* Session hash global list for L2TPv3.
163 * The session_id SHOULD be random according to RFC3931, but several
164 * L2TP implementations use incrementing session_ids. So we do a real
165 * hash on the session_id, rather than a simple bitmask.
167 static inline struct hlist_head
*
168 l2tp_session_id_hash_2(struct l2tp_net
*pn
, u32 session_id
)
170 return &pn
->l2tp_session_hlist
[hash_32(session_id
, L2TP_HASH_BITS_2
)];
174 /* Lookup the tunnel socket, possibly involving the fs code if the socket is
175 * owned by userspace. A struct sock returned from this function must be
176 * released using l2tp_tunnel_sock_put once you're done with it.
178 static struct sock
*l2tp_tunnel_sock_lookup(struct l2tp_tunnel
*tunnel
)
181 struct socket
*sock
= NULL
;
182 struct sock
*sk
= NULL
;
187 if (tunnel
->fd
>= 0) {
188 /* Socket is owned by userspace, who might be in the process
189 * of closing it. Look the socket up using the fd to ensure
192 sock
= sockfd_lookup(tunnel
->fd
, &err
);
196 /* Socket is owned by kernelspace */
205 /* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */
206 static void l2tp_tunnel_sock_put(struct sock
*sk
)
208 struct l2tp_tunnel
*tunnel
= l2tp_sock_to_tunnel(sk
);
210 if (tunnel
->fd
>= 0) {
211 /* Socket is owned by userspace */
212 sockfd_put(sk
->sk_socket
);
219 /* Lookup a session by id in the global session list
221 static struct l2tp_session
*l2tp_session_find_2(struct net
*net
, u32 session_id
)
223 struct l2tp_net
*pn
= l2tp_pernet(net
);
224 struct hlist_head
*session_list
=
225 l2tp_session_id_hash_2(pn
, session_id
);
226 struct l2tp_session
*session
;
229 hlist_for_each_entry_rcu(session
, session_list
, global_hlist
) {
230 if (session
->session_id
== session_id
) {
231 rcu_read_unlock_bh();
235 rcu_read_unlock_bh();
240 /* Session hash list.
241 * The session_id SHOULD be random according to RFC2661, but several
242 * L2TP implementations (Cisco and Microsoft) use incrementing
243 * session_ids. So we do a real hash on the session_id, rather than a
246 static inline struct hlist_head
*
247 l2tp_session_id_hash(struct l2tp_tunnel
*tunnel
, u32 session_id
)
249 return &tunnel
->session_hlist
[hash_32(session_id
, L2TP_HASH_BITS
)];
252 /* Lookup a session by id
254 struct l2tp_session
*l2tp_session_find(struct net
*net
, struct l2tp_tunnel
*tunnel
, u32 session_id
)
256 struct hlist_head
*session_list
;
257 struct l2tp_session
*session
;
259 /* In L2TPv3, session_ids are unique over all tunnels and we
260 * sometimes need to look them up before we know the
264 return l2tp_session_find_2(net
, session_id
);
266 session_list
= l2tp_session_id_hash(tunnel
, session_id
);
267 read_lock_bh(&tunnel
->hlist_lock
);
268 hlist_for_each_entry(session
, session_list
, hlist
) {
269 if (session
->session_id
== session_id
) {
270 read_unlock_bh(&tunnel
->hlist_lock
);
274 read_unlock_bh(&tunnel
->hlist_lock
);
278 EXPORT_SYMBOL_GPL(l2tp_session_find
);
280 struct l2tp_session
*l2tp_session_find_nth(struct l2tp_tunnel
*tunnel
, int nth
)
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
, &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 l2tp_session
*session
;
312 for (hash
= 0; hash
< L2TP_HASH_SIZE_2
; hash
++) {
313 hlist_for_each_entry_rcu(session
, &pn
->l2tp_session_hlist
[hash
], global_hlist
) {
314 if (!strcmp(session
->ifname
, ifname
)) {
315 rcu_read_unlock_bh();
321 rcu_read_unlock_bh();
325 EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname
);
327 /* Lookup a tunnel by id
329 struct l2tp_tunnel
*l2tp_tunnel_find(struct net
*net
, u32 tunnel_id
)
331 struct l2tp_tunnel
*tunnel
;
332 struct l2tp_net
*pn
= l2tp_pernet(net
);
335 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
336 if (tunnel
->tunnel_id
== tunnel_id
) {
337 rcu_read_unlock_bh();
341 rcu_read_unlock_bh();
345 EXPORT_SYMBOL_GPL(l2tp_tunnel_find
);
347 struct l2tp_tunnel
*l2tp_tunnel_find_nth(struct net
*net
, int nth
)
349 struct l2tp_net
*pn
= l2tp_pernet(net
);
350 struct l2tp_tunnel
*tunnel
;
354 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
356 rcu_read_unlock_bh();
361 rcu_read_unlock_bh();
365 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth
);
367 /*****************************************************************************
368 * Receive data handling
369 *****************************************************************************/
371 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
374 static void l2tp_recv_queue_skb(struct l2tp_session
*session
, struct sk_buff
*skb
)
376 struct sk_buff
*skbp
;
378 u32 ns
= L2TP_SKB_CB(skb
)->ns
;
380 spin_lock_bh(&session
->reorder_q
.lock
);
381 skb_queue_walk_safe(&session
->reorder_q
, skbp
, tmp
) {
382 if (L2TP_SKB_CB(skbp
)->ns
> ns
) {
383 __skb_queue_before(&session
->reorder_q
, skbp
, skb
);
384 l2tp_dbg(session
, L2TP_MSG_SEQ
,
385 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
386 session
->name
, ns
, L2TP_SKB_CB(skbp
)->ns
,
387 skb_queue_len(&session
->reorder_q
));
388 atomic_long_inc(&session
->stats
.rx_oos_packets
);
393 __skb_queue_tail(&session
->reorder_q
, skb
);
396 spin_unlock_bh(&session
->reorder_q
.lock
);
399 /* Dequeue a single skb.
401 static void l2tp_recv_dequeue_skb(struct l2tp_session
*session
, struct sk_buff
*skb
)
403 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
404 int length
= L2TP_SKB_CB(skb
)->length
;
406 /* We're about to requeue the skb, so return resources
407 * to its current owner (a socket receive buffer).
411 atomic_long_inc(&tunnel
->stats
.rx_packets
);
412 atomic_long_add(length
, &tunnel
->stats
.rx_bytes
);
413 atomic_long_inc(&session
->stats
.rx_packets
);
414 atomic_long_add(length
, &session
->stats
.rx_bytes
);
416 if (L2TP_SKB_CB(skb
)->has_seq
) {
419 session
->nr
&= session
->nr_max
;
421 l2tp_dbg(session
, L2TP_MSG_SEQ
, "%s: updated nr to %hu\n",
422 session
->name
, session
->nr
);
425 /* call private receive handler */
426 if (session
->recv_skb
!= NULL
)
427 (*session
->recv_skb
)(session
, skb
, L2TP_SKB_CB(skb
)->length
);
432 (*session
->deref
)(session
);
435 /* Dequeue skbs from the session's reorder_q, subject to packet order.
436 * Skbs that have been in the queue for too long are simply discarded.
438 static void l2tp_recv_dequeue(struct l2tp_session
*session
)
443 /* If the pkt at the head of the queue has the nr that we
444 * expect to send up next, dequeue it and any other
445 * in-sequence packets behind it.
448 spin_lock_bh(&session
->reorder_q
.lock
);
449 skb_queue_walk_safe(&session
->reorder_q
, skb
, tmp
) {
450 if (time_after(jiffies
, L2TP_SKB_CB(skb
)->expires
)) {
451 atomic_long_inc(&session
->stats
.rx_seq_discards
);
452 atomic_long_inc(&session
->stats
.rx_errors
);
453 l2tp_dbg(session
, L2TP_MSG_SEQ
,
454 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
455 session
->name
, L2TP_SKB_CB(skb
)->ns
,
456 L2TP_SKB_CB(skb
)->length
, session
->nr
,
457 skb_queue_len(&session
->reorder_q
));
458 session
->reorder_skip
= 1;
459 __skb_unlink(skb
, &session
->reorder_q
);
462 (*session
->deref
)(session
);
466 if (L2TP_SKB_CB(skb
)->has_seq
) {
467 if (session
->reorder_skip
) {
468 l2tp_dbg(session
, L2TP_MSG_SEQ
,
469 "%s: advancing nr to next pkt: %u -> %u",
470 session
->name
, session
->nr
,
471 L2TP_SKB_CB(skb
)->ns
);
472 session
->reorder_skip
= 0;
473 session
->nr
= L2TP_SKB_CB(skb
)->ns
;
475 if (L2TP_SKB_CB(skb
)->ns
!= session
->nr
) {
476 l2tp_dbg(session
, L2TP_MSG_SEQ
,
477 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
478 session
->name
, L2TP_SKB_CB(skb
)->ns
,
479 L2TP_SKB_CB(skb
)->length
, session
->nr
,
480 skb_queue_len(&session
->reorder_q
));
484 __skb_unlink(skb
, &session
->reorder_q
);
486 /* Process the skb. We release the queue lock while we
487 * do so to let other contexts process the queue.
489 spin_unlock_bh(&session
->reorder_q
.lock
);
490 l2tp_recv_dequeue_skb(session
, skb
);
495 spin_unlock_bh(&session
->reorder_q
.lock
);
498 static int l2tp_seq_check_rx_window(struct l2tp_session
*session
, u32 nr
)
502 if (nr
>= session
->nr
)
503 nws
= nr
- session
->nr
;
505 nws
= (session
->nr_max
+ 1) - (session
->nr
- nr
);
507 return nws
< session
->nr_window_size
;
510 /* If packet has sequence numbers, queue it if acceptable. Returns 0 if
511 * acceptable, else non-zero.
513 static int l2tp_recv_data_seq(struct l2tp_session
*session
, struct sk_buff
*skb
)
515 if (!l2tp_seq_check_rx_window(session
, L2TP_SKB_CB(skb
)->ns
)) {
516 /* Packet sequence number is outside allowed window.
519 l2tp_dbg(session
, L2TP_MSG_SEQ
,
520 "%s: pkt %u len %d discarded, outside window, nr=%u\n",
521 session
->name
, L2TP_SKB_CB(skb
)->ns
,
522 L2TP_SKB_CB(skb
)->length
, session
->nr
);
526 if (session
->reorder_timeout
!= 0) {
527 /* Packet reordering enabled. Add skb to session's
528 * reorder queue, in order of ns.
530 l2tp_recv_queue_skb(session
, skb
);
534 /* Packet reordering disabled. Discard out-of-sequence packets, while
535 * tracking the number if in-sequence packets after the first OOS packet
536 * is seen. After nr_oos_count_max in-sequence packets, reset the
537 * sequence number to re-enable packet reception.
539 if (L2TP_SKB_CB(skb
)->ns
== session
->nr
) {
540 skb_queue_tail(&session
->reorder_q
, skb
);
542 u32 nr_oos
= L2TP_SKB_CB(skb
)->ns
;
543 u32 nr_next
= (session
->nr_oos
+ 1) & session
->nr_max
;
545 if (nr_oos
== nr_next
)
546 session
->nr_oos_count
++;
548 session
->nr_oos_count
= 0;
550 session
->nr_oos
= nr_oos
;
551 if (session
->nr_oos_count
> session
->nr_oos_count_max
) {
552 session
->reorder_skip
= 1;
553 l2tp_dbg(session
, L2TP_MSG_SEQ
,
554 "%s: %d oos packets received. Resetting sequence numbers\n",
555 session
->name
, session
->nr_oos_count
);
557 if (!session
->reorder_skip
) {
558 atomic_long_inc(&session
->stats
.rx_seq_discards
);
559 l2tp_dbg(session
, L2TP_MSG_SEQ
,
560 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
561 session
->name
, L2TP_SKB_CB(skb
)->ns
,
562 L2TP_SKB_CB(skb
)->length
, session
->nr
,
563 skb_queue_len(&session
->reorder_q
));
566 skb_queue_tail(&session
->reorder_q
, skb
);
576 /* Do receive processing of L2TP data frames. We handle both L2TPv2
577 * and L2TPv3 data frames here.
579 * L2TPv2 Data Message Header
582 * 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
583 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
584 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
585 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
586 * | Tunnel ID | Session ID |
587 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
588 * | Ns (opt) | Nr (opt) |
589 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
590 * | Offset Size (opt) | Offset pad... (opt)
591 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
593 * Data frames are marked by T=0. All other fields are the same as
594 * those in L2TP control frames.
596 * L2TPv3 Data Message Header
598 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
599 * | L2TP Session Header |
600 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
601 * | L2-Specific Sublayer |
602 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
603 * | Tunnel Payload ...
604 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
606 * L2TPv3 Session Header Over IP
609 * 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
610 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
612 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
613 * | Cookie (optional, maximum 64 bits)...
614 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
616 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
618 * L2TPv3 L2-Specific Sublayer Format
621 * 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
622 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
623 * |x|S|x|x|x|x|x|x| Sequence Number |
624 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
626 * Cookie value, sublayer format and offset (pad) are negotiated with
627 * the peer when the session is set up. Unlike L2TPv2, we do not need
628 * to parse the packet header to determine if optional fields are
631 * Caller must already have parsed the frame and determined that it is
632 * a data (not control) frame before coming here. Fields up to the
633 * session-id have already been parsed and ptr points to the data
634 * after the session-id.
636 void l2tp_recv_common(struct l2tp_session
*session
, struct sk_buff
*skb
,
637 unsigned char *ptr
, unsigned char *optr
, u16 hdrflags
,
638 int length
, int (*payload_hook
)(struct sk_buff
*skb
))
640 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
644 /* The ref count is increased since we now hold a pointer to
645 * the session. Take care to decrement the refcnt when exiting
646 * this function from now on...
648 l2tp_session_inc_refcount(session
);
650 (*session
->ref
)(session
);
652 /* Parse and check optional cookie */
653 if (session
->peer_cookie_len
> 0) {
654 if (memcmp(ptr
, &session
->peer_cookie
[0], session
->peer_cookie_len
)) {
655 l2tp_info(tunnel
, L2TP_MSG_DATA
,
656 "%s: cookie mismatch (%u/%u). Discarding.\n",
657 tunnel
->name
, tunnel
->tunnel_id
,
658 session
->session_id
);
659 atomic_long_inc(&session
->stats
.rx_cookie_discards
);
662 ptr
+= session
->peer_cookie_len
;
665 /* Handle the optional sequence numbers. Sequence numbers are
666 * in different places for L2TPv2 and L2TPv3.
668 * If we are the LAC, enable/disable sequence numbers under
669 * the control of the LNS. If no sequence numbers present but
670 * we were expecting them, discard frame.
673 L2TP_SKB_CB(skb
)->has_seq
= 0;
674 if (tunnel
->version
== L2TP_HDR_VER_2
) {
675 if (hdrflags
& L2TP_HDRFLAG_S
) {
676 ns
= ntohs(*(__be16
*) ptr
);
678 nr
= ntohs(*(__be16
*) ptr
);
681 /* Store L2TP info in the skb */
682 L2TP_SKB_CB(skb
)->ns
= ns
;
683 L2TP_SKB_CB(skb
)->has_seq
= 1;
685 l2tp_dbg(session
, L2TP_MSG_SEQ
,
686 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
687 session
->name
, ns
, nr
, session
->nr
);
689 } else if (session
->l2specific_type
== L2TP_L2SPECTYPE_DEFAULT
) {
690 u32 l2h
= ntohl(*(__be32
*) ptr
);
692 if (l2h
& 0x40000000) {
693 ns
= l2h
& 0x00ffffff;
695 /* Store L2TP info in the skb */
696 L2TP_SKB_CB(skb
)->ns
= ns
;
697 L2TP_SKB_CB(skb
)->has_seq
= 1;
699 l2tp_dbg(session
, L2TP_MSG_SEQ
,
700 "%s: recv data ns=%u, session nr=%u\n",
701 session
->name
, ns
, session
->nr
);
705 /* Advance past L2-specific header, if present */
706 ptr
+= session
->l2specific_len
;
708 if (L2TP_SKB_CB(skb
)->has_seq
) {
709 /* Received a packet with sequence numbers. If we're the LNS,
710 * check if we sre sending sequence numbers and if not,
713 if ((!session
->lns_mode
) && (!session
->send_seq
)) {
714 l2tp_info(session
, L2TP_MSG_SEQ
,
715 "%s: requested to enable seq numbers by LNS\n",
717 session
->send_seq
= -1;
718 l2tp_session_set_header_len(session
, tunnel
->version
);
721 /* No sequence numbers.
722 * If user has configured mandatory sequence numbers, discard.
724 if (session
->recv_seq
) {
725 l2tp_warn(session
, L2TP_MSG_SEQ
,
726 "%s: recv data has no seq numbers when required. Discarding.\n",
728 atomic_long_inc(&session
->stats
.rx_seq_discards
);
732 /* If we're the LAC and we're sending sequence numbers, the
733 * LNS has requested that we no longer send sequence numbers.
734 * If we're the LNS and we're sending sequence numbers, the
735 * LAC is broken. Discard the frame.
737 if ((!session
->lns_mode
) && (session
->send_seq
)) {
738 l2tp_info(session
, L2TP_MSG_SEQ
,
739 "%s: requested to disable seq numbers by LNS\n",
741 session
->send_seq
= 0;
742 l2tp_session_set_header_len(session
, tunnel
->version
);
743 } else if (session
->send_seq
) {
744 l2tp_warn(session
, L2TP_MSG_SEQ
,
745 "%s: recv data has no seq numbers when required. Discarding.\n",
747 atomic_long_inc(&session
->stats
.rx_seq_discards
);
752 /* Session data offset is handled differently for L2TPv2 and
753 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
754 * the header. For L2TPv3, the offset is negotiated using AVPs
755 * in the session setup control protocol.
757 if (tunnel
->version
== L2TP_HDR_VER_2
) {
758 /* If offset bit set, skip it. */
759 if (hdrflags
& L2TP_HDRFLAG_O
) {
760 offset
= ntohs(*(__be16
*)ptr
);
764 ptr
+= session
->offset
;
767 if (!pskb_may_pull(skb
, offset
))
770 __skb_pull(skb
, offset
);
772 /* If caller wants to process the payload before we queue the
776 if ((*payload_hook
)(skb
))
779 /* Prepare skb for adding to the session's reorder_q. Hold
780 * packets for max reorder_timeout or 1 second if not
783 L2TP_SKB_CB(skb
)->length
= length
;
784 L2TP_SKB_CB(skb
)->expires
= jiffies
+
785 (session
->reorder_timeout
? session
->reorder_timeout
: HZ
);
787 /* Add packet to the session's receive queue. Reordering is done here, if
788 * enabled. Saved L2TP protocol info is stored in skb->sb[].
790 if (L2TP_SKB_CB(skb
)->has_seq
) {
791 if (l2tp_recv_data_seq(session
, skb
))
794 /* No sequence numbers. Add the skb to the tail of the
795 * reorder queue. This ensures that it will be
796 * delivered after all previous sequenced skbs.
798 skb_queue_tail(&session
->reorder_q
, skb
);
801 /* Try to dequeue as many skbs from reorder_q as we can. */
802 l2tp_recv_dequeue(session
);
804 l2tp_session_dec_refcount(session
);
809 atomic_long_inc(&session
->stats
.rx_errors
);
813 (*session
->deref
)(session
);
815 l2tp_session_dec_refcount(session
);
817 EXPORT_SYMBOL(l2tp_recv_common
);
819 /* Drop skbs from the session's reorder_q
821 int l2tp_session_queue_purge(struct l2tp_session
*session
)
823 struct sk_buff
*skb
= NULL
;
825 BUG_ON(session
->magic
!= L2TP_SESSION_MAGIC
);
826 while ((skb
= skb_dequeue(&session
->reorder_q
))) {
827 atomic_long_inc(&session
->stats
.rx_errors
);
830 (*session
->deref
)(session
);
834 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge
);
836 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
837 * here. The skb is not on a list when we get here.
838 * Returns 0 if the packet was a data packet and was successfully passed on.
839 * Returns 1 if the packet was not a good data packet and could not be
840 * forwarded. All such packets are passed up to userspace to deal with.
842 static int l2tp_udp_recv_core(struct l2tp_tunnel
*tunnel
, struct sk_buff
*skb
,
843 int (*payload_hook
)(struct sk_buff
*skb
))
845 struct l2tp_session
*session
= NULL
;
846 unsigned char *ptr
, *optr
;
848 u32 tunnel_id
, session_id
;
852 /* UDP has verifed checksum */
854 /* UDP always verifies the packet length. */
855 __skb_pull(skb
, sizeof(struct udphdr
));
858 if (!pskb_may_pull(skb
, L2TP_HDR_SIZE_SEQ
)) {
859 l2tp_info(tunnel
, L2TP_MSG_DATA
,
860 "%s: recv short packet (len=%d)\n",
861 tunnel
->name
, skb
->len
);
865 /* Trace packet contents, if enabled */
866 if (tunnel
->debug
& L2TP_MSG_DATA
) {
867 length
= min(32u, skb
->len
);
868 if (!pskb_may_pull(skb
, length
))
871 pr_debug("%s: recv\n", tunnel
->name
);
872 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET
, skb
->data
, length
);
875 /* Point to L2TP header */
876 optr
= ptr
= skb
->data
;
878 /* Get L2TP header flags */
879 hdrflags
= ntohs(*(__be16
*) ptr
);
881 /* Check protocol version */
882 version
= hdrflags
& L2TP_HDR_VER_MASK
;
883 if (version
!= tunnel
->version
) {
884 l2tp_info(tunnel
, L2TP_MSG_DATA
,
885 "%s: recv protocol version mismatch: got %d expected %d\n",
886 tunnel
->name
, version
, tunnel
->version
);
890 /* Get length of L2TP packet */
893 /* If type is control packet, it is handled by userspace. */
894 if (hdrflags
& L2TP_HDRFLAG_T
) {
895 l2tp_dbg(tunnel
, L2TP_MSG_DATA
,
896 "%s: recv control packet, len=%d\n",
897 tunnel
->name
, length
);
904 if (tunnel
->version
== L2TP_HDR_VER_2
) {
905 /* If length is present, skip it */
906 if (hdrflags
& L2TP_HDRFLAG_L
)
909 /* Extract tunnel and session ID */
910 tunnel_id
= ntohs(*(__be16
*) ptr
);
912 session_id
= ntohs(*(__be16
*) ptr
);
915 ptr
+= 2; /* skip reserved bits */
916 tunnel_id
= tunnel
->tunnel_id
;
917 session_id
= ntohl(*(__be32
*) ptr
);
921 /* Find the session context */
922 session
= l2tp_session_find(tunnel
->l2tp_net
, tunnel
, session_id
);
923 if (!session
|| !session
->recv_skb
) {
924 /* Not found? Pass to userspace to deal with */
925 l2tp_info(tunnel
, L2TP_MSG_DATA
,
926 "%s: no session found (%u/%u). Passing up.\n",
927 tunnel
->name
, tunnel_id
, session_id
);
931 l2tp_recv_common(session
, skb
, ptr
, optr
, hdrflags
, length
, payload_hook
);
936 /* Put UDP header back */
937 __skb_push(skb
, sizeof(struct udphdr
));
942 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
946 * >0: skb should be passed up to userspace as UDP.
948 int l2tp_udp_encap_recv(struct sock
*sk
, struct sk_buff
*skb
)
950 struct l2tp_tunnel
*tunnel
;
952 tunnel
= l2tp_sock_to_tunnel(sk
);
956 l2tp_dbg(tunnel
, L2TP_MSG_DATA
, "%s: received %d bytes\n",
957 tunnel
->name
, skb
->len
);
959 if (l2tp_udp_recv_core(tunnel
, skb
, tunnel
->recv_payload_hook
))
970 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv
);
972 /************************************************************************
974 ***********************************************************************/
976 /* Build an L2TP header for the session into the buffer provided.
978 static int l2tp_build_l2tpv2_header(struct l2tp_session
*session
, void *buf
)
980 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
983 u16 flags
= L2TP_HDR_VER_2
;
984 u32 tunnel_id
= tunnel
->peer_tunnel_id
;
985 u32 session_id
= session
->peer_session_id
;
987 if (session
->send_seq
)
988 flags
|= L2TP_HDRFLAG_S
;
990 /* Setup L2TP header. */
991 *bufp
++ = htons(flags
);
992 *bufp
++ = htons(tunnel_id
);
993 *bufp
++ = htons(session_id
);
994 if (session
->send_seq
) {
995 *bufp
++ = htons(session
->ns
);
998 session
->ns
&= 0xffff;
999 l2tp_dbg(session
, L2TP_MSG_SEQ
, "%s: updated ns to %u\n",
1000 session
->name
, session
->ns
);
1006 static int l2tp_build_l2tpv3_header(struct l2tp_session
*session
, void *buf
)
1008 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1012 /* Setup L2TP header. The header differs slightly for UDP and
1013 * IP encapsulations. For UDP, there is 4 bytes of flags.
1015 if (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) {
1016 u16 flags
= L2TP_HDR_VER_3
;
1017 *((__be16
*) bufp
) = htons(flags
);
1019 *((__be16
*) bufp
) = 0;
1023 *((__be32
*) bufp
) = htonl(session
->peer_session_id
);
1025 if (session
->cookie_len
) {
1026 memcpy(bufp
, &session
->cookie
[0], session
->cookie_len
);
1027 bufp
+= session
->cookie_len
;
1029 if (session
->l2specific_len
) {
1030 if (session
->l2specific_type
== L2TP_L2SPECTYPE_DEFAULT
) {
1032 if (session
->send_seq
) {
1033 l2h
= 0x40000000 | session
->ns
;
1035 session
->ns
&= 0xffffff;
1036 l2tp_dbg(session
, L2TP_MSG_SEQ
,
1037 "%s: updated ns to %u\n",
1038 session
->name
, session
->ns
);
1041 *((__be32
*) bufp
) = htonl(l2h
);
1043 bufp
+= session
->l2specific_len
;
1045 if (session
->offset
)
1046 bufp
+= session
->offset
;
1051 static int l2tp_xmit_core(struct l2tp_session
*session
, struct sk_buff
*skb
,
1052 struct flowi
*fl
, size_t data_len
)
1054 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1055 unsigned int len
= skb
->len
;
1059 if (session
->send_seq
)
1060 l2tp_dbg(session
, L2TP_MSG_DATA
, "%s: send %Zd bytes, ns=%u\n",
1061 session
->name
, data_len
, session
->ns
- 1);
1063 l2tp_dbg(session
, L2TP_MSG_DATA
, "%s: send %Zd bytes\n",
1064 session
->name
, data_len
);
1066 if (session
->debug
& L2TP_MSG_DATA
) {
1067 int uhlen
= (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) ? sizeof(struct udphdr
) : 0;
1068 unsigned char *datap
= skb
->data
+ uhlen
;
1070 pr_debug("%s: xmit\n", session
->name
);
1071 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET
,
1072 datap
, min_t(size_t, 32, len
- uhlen
));
1075 /* Queue the packet to IP for output */
1077 #if IS_ENABLED(CONFIG_IPV6)
1078 if (tunnel
->sock
->sk_family
== PF_INET6
&& !tunnel
->v4mapped
)
1079 error
= inet6_csk_xmit(tunnel
->sock
, skb
, NULL
);
1082 error
= ip_queue_xmit(tunnel
->sock
, skb
, fl
);
1086 atomic_long_inc(&tunnel
->stats
.tx_packets
);
1087 atomic_long_add(len
, &tunnel
->stats
.tx_bytes
);
1088 atomic_long_inc(&session
->stats
.tx_packets
);
1089 atomic_long_add(len
, &session
->stats
.tx_bytes
);
1091 atomic_long_inc(&tunnel
->stats
.tx_errors
);
1092 atomic_long_inc(&session
->stats
.tx_errors
);
1098 #if IS_ENABLED(CONFIG_IPV6)
1099 static void l2tp_xmit_ipv6_csum(struct sock
*sk
, struct sk_buff
*skb
,
1102 struct ipv6_pinfo
*np
= inet6_sk(sk
);
1103 struct udphdr
*uh
= udp_hdr(skb
);
1105 if (!skb_dst(skb
) || !skb_dst(skb
)->dev
||
1106 !(skb_dst(skb
)->dev
->features
& NETIF_F_IPV6_CSUM
)) {
1107 __wsum csum
= skb_checksum(skb
, 0, udp_len
, 0);
1108 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
1109 uh
->check
= csum_ipv6_magic(&np
->saddr
, &sk
->sk_v6_daddr
, udp_len
,
1112 uh
->check
= CSUM_MANGLED_0
;
1114 skb
->ip_summed
= CHECKSUM_PARTIAL
;
1115 skb
->csum_start
= skb_transport_header(skb
) - skb
->head
;
1116 skb
->csum_offset
= offsetof(struct udphdr
, check
);
1117 uh
->check
= ~csum_ipv6_magic(&np
->saddr
, &sk
->sk_v6_daddr
,
1118 udp_len
, IPPROTO_UDP
, 0);
1123 /* If caller requires the skb to have a ppp header, the header must be
1124 * inserted in the skb data before calling this function.
1126 int l2tp_xmit_skb(struct l2tp_session
*session
, struct sk_buff
*skb
, int hdr_len
)
1128 int data_len
= skb
->len
;
1129 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1130 struct sock
*sk
= tunnel
->sock
;
1133 struct inet_sock
*inet
;
1136 int uhlen
= (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) ? sizeof(struct udphdr
) : 0;
1138 int ret
= NET_XMIT_SUCCESS
;
1140 /* Check that there's enough headroom in the skb to insert IP,
1141 * UDP and L2TP headers. If not enough, expand it to
1142 * make room. Adjust truesize.
1144 headroom
= NET_SKB_PAD
+ sizeof(struct iphdr
) +
1146 if (skb_cow_head(skb
, headroom
)) {
1148 return NET_XMIT_DROP
;
1151 /* Setup L2TP header */
1152 session
->build_header(session
, __skb_push(skb
, hdr_len
));
1154 /* Reset skb netfilter state */
1155 memset(&(IPCB(skb
)->opt
), 0, sizeof(IPCB(skb
)->opt
));
1156 IPCB(skb
)->flags
&= ~(IPSKB_XFRM_TUNNEL_SIZE
| IPSKB_XFRM_TRANSFORMED
|
1161 if (sock_owned_by_user(sk
)) {
1163 ret
= NET_XMIT_DROP
;
1167 /* Get routing info from the tunnel socket */
1169 skb_dst_set(skb
, dst_clone(__sk_dst_check(sk
, 0)));
1172 fl
= &inet
->cork
.fl
;
1173 switch (tunnel
->encap
) {
1174 case L2TP_ENCAPTYPE_UDP
:
1175 /* Setup UDP header */
1176 __skb_push(skb
, sizeof(*uh
));
1177 skb_reset_transport_header(skb
);
1179 uh
->source
= inet
->inet_sport
;
1180 uh
->dest
= inet
->inet_dport
;
1181 udp_len
= uhlen
+ hdr_len
+ data_len
;
1182 uh
->len
= htons(udp_len
);
1185 /* Calculate UDP checksum if configured to do so */
1186 #if IS_ENABLED(CONFIG_IPV6)
1187 if (sk
->sk_family
== PF_INET6
&& !tunnel
->v4mapped
)
1188 l2tp_xmit_ipv6_csum(sk
, skb
, udp_len
);
1191 if (sk
->sk_no_check
== UDP_CSUM_NOXMIT
)
1192 skb
->ip_summed
= CHECKSUM_NONE
;
1193 else if ((skb_dst(skb
) && skb_dst(skb
)->dev
) &&
1194 (!(skb_dst(skb
)->dev
->features
& NETIF_F_V4_CSUM
))) {
1195 skb
->ip_summed
= CHECKSUM_COMPLETE
;
1196 csum
= skb_checksum(skb
, 0, udp_len
, 0);
1197 uh
->check
= csum_tcpudp_magic(inet
->inet_saddr
,
1199 udp_len
, IPPROTO_UDP
, csum
);
1201 uh
->check
= CSUM_MANGLED_0
;
1203 skb
->ip_summed
= CHECKSUM_PARTIAL
;
1204 skb
->csum_start
= skb_transport_header(skb
) - skb
->head
;
1205 skb
->csum_offset
= offsetof(struct udphdr
, check
);
1206 uh
->check
= ~csum_tcpudp_magic(inet
->inet_saddr
,
1208 udp_len
, IPPROTO_UDP
, 0);
1212 case L2TP_ENCAPTYPE_IP
:
1216 l2tp_xmit_core(session
, skb
, fl
, data_len
);
1222 EXPORT_SYMBOL_GPL(l2tp_xmit_skb
);
1224 /*****************************************************************************
1225 * Tinnel and session create/destroy.
1226 *****************************************************************************/
1228 /* Tunnel socket destruct hook.
1229 * The tunnel context is deleted only when all session sockets have been
1232 static void l2tp_tunnel_destruct(struct sock
*sk
)
1234 struct l2tp_tunnel
*tunnel
= l2tp_tunnel(sk
);
1235 struct l2tp_net
*pn
;
1240 l2tp_info(tunnel
, L2TP_MSG_CONTROL
, "%s: closing...\n", tunnel
->name
);
1243 /* Disable udp encapsulation */
1244 switch (tunnel
->encap
) {
1245 case L2TP_ENCAPTYPE_UDP
:
1246 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1247 (udp_sk(sk
))->encap_type
= 0;
1248 (udp_sk(sk
))->encap_rcv
= NULL
;
1249 (udp_sk(sk
))->encap_destroy
= NULL
;
1251 case L2TP_ENCAPTYPE_IP
:
1255 /* Remove hooks into tunnel socket */
1256 sk
->sk_destruct
= tunnel
->old_sk_destruct
;
1257 sk
->sk_user_data
= NULL
;
1258 tunnel
->sock
= NULL
;
1260 /* Remove the tunnel struct from the tunnel list */
1261 pn
= l2tp_pernet(tunnel
->l2tp_net
);
1262 spin_lock_bh(&pn
->l2tp_tunnel_list_lock
);
1263 list_del_rcu(&tunnel
->list
);
1264 spin_unlock_bh(&pn
->l2tp_tunnel_list_lock
);
1265 atomic_dec(&l2tp_tunnel_count
);
1267 l2tp_tunnel_closeall(tunnel
);
1268 l2tp_tunnel_dec_refcount(tunnel
);
1270 /* Call the original destructor */
1271 if (sk
->sk_destruct
)
1272 (*sk
->sk_destruct
)(sk
);
1277 /* When the tunnel is closed, all the attached sessions need to go too.
1279 void l2tp_tunnel_closeall(struct l2tp_tunnel
*tunnel
)
1282 struct hlist_node
*walk
;
1283 struct hlist_node
*tmp
;
1284 struct l2tp_session
*session
;
1286 BUG_ON(tunnel
== NULL
);
1288 l2tp_info(tunnel
, L2TP_MSG_CONTROL
, "%s: closing all sessions...\n",
1291 write_lock_bh(&tunnel
->hlist_lock
);
1292 for (hash
= 0; hash
< L2TP_HASH_SIZE
; hash
++) {
1294 hlist_for_each_safe(walk
, tmp
, &tunnel
->session_hlist
[hash
]) {
1295 session
= hlist_entry(walk
, struct l2tp_session
, hlist
);
1297 l2tp_info(session
, L2TP_MSG_CONTROL
,
1298 "%s: closing session\n", session
->name
);
1300 hlist_del_init(&session
->hlist
);
1302 if (session
->ref
!= NULL
)
1303 (*session
->ref
)(session
);
1305 write_unlock_bh(&tunnel
->hlist_lock
);
1307 __l2tp_session_unhash(session
);
1308 l2tp_session_queue_purge(session
);
1310 if (session
->session_close
!= NULL
)
1311 (*session
->session_close
)(session
);
1313 if (session
->deref
!= NULL
)
1314 (*session
->deref
)(session
);
1316 l2tp_session_dec_refcount(session
);
1318 write_lock_bh(&tunnel
->hlist_lock
);
1320 /* Now restart from the beginning of this hash
1321 * chain. We always remove a session from the
1322 * list so we are guaranteed to make forward
1328 write_unlock_bh(&tunnel
->hlist_lock
);
1330 EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall
);
1332 /* Tunnel socket destroy hook for UDP encapsulation */
1333 static void l2tp_udp_encap_destroy(struct sock
*sk
)
1335 struct l2tp_tunnel
*tunnel
= l2tp_sock_to_tunnel(sk
);
1337 l2tp_tunnel_closeall(tunnel
);
1342 /* Really kill the tunnel.
1343 * Come here only when all sessions have been cleared from the tunnel.
1345 static void l2tp_tunnel_free(struct l2tp_tunnel
*tunnel
)
1347 BUG_ON(atomic_read(&tunnel
->ref_count
) != 0);
1348 BUG_ON(tunnel
->sock
!= NULL
);
1349 l2tp_info(tunnel
, L2TP_MSG_CONTROL
, "%s: free...\n", tunnel
->name
);
1350 kfree_rcu(tunnel
, rcu
);
1353 /* Workqueue tunnel deletion function */
1354 static void l2tp_tunnel_del_work(struct work_struct
*work
)
1356 struct l2tp_tunnel
*tunnel
= NULL
;
1357 struct socket
*sock
= NULL
;
1358 struct sock
*sk
= NULL
;
1360 tunnel
= container_of(work
, struct l2tp_tunnel
, del_work
);
1361 sk
= l2tp_tunnel_sock_lookup(tunnel
);
1365 sock
= sk
->sk_socket
;
1367 /* If the tunnel socket was created by userspace, then go through the
1368 * inet layer to shut the socket down, and let userspace close it.
1369 * Otherwise, if we created the socket directly within the kernel, use
1370 * the sk API to release it here.
1371 * In either case the tunnel resources are freed in the socket
1372 * destructor when the tunnel socket goes away.
1374 if (tunnel
->fd
>= 0) {
1376 inet_shutdown(sock
, 2);
1379 kernel_sock_shutdown(sock
, SHUT_RDWR
);
1380 sk_release_kernel(sk
);
1383 l2tp_tunnel_sock_put(sk
);
1386 /* Create a socket for the tunnel, if one isn't set up by
1387 * userspace. This is used for static tunnels where there is no
1388 * managing L2TP daemon.
1390 * Since we don't want these sockets to keep a namespace alive by
1391 * themselves, we drop the socket's namespace refcount after creation.
1392 * These sockets are freed when the namespace exits using the pernet
1395 static int l2tp_tunnel_sock_create(struct net
*net
,
1398 struct l2tp_tunnel_cfg
*cfg
,
1399 struct socket
**sockp
)
1402 struct socket
*sock
= NULL
;
1403 struct sockaddr_in udp_addr
= {0};
1404 struct sockaddr_l2tpip ip_addr
= {0};
1405 #if IS_ENABLED(CONFIG_IPV6)
1406 struct sockaddr_in6 udp6_addr
= {0};
1407 struct sockaddr_l2tpip6 ip6_addr
= {0};
1410 switch (cfg
->encap
) {
1411 case L2TP_ENCAPTYPE_UDP
:
1412 #if IS_ENABLED(CONFIG_IPV6)
1413 if (cfg
->local_ip6
&& cfg
->peer_ip6
) {
1414 err
= sock_create_kern(AF_INET6
, SOCK_DGRAM
, 0, &sock
);
1418 sk_change_net(sock
->sk
, net
);
1420 udp6_addr
.sin6_family
= AF_INET6
;
1421 memcpy(&udp6_addr
.sin6_addr
, cfg
->local_ip6
,
1422 sizeof(udp6_addr
.sin6_addr
));
1423 udp6_addr
.sin6_port
= htons(cfg
->local_udp_port
);
1424 err
= kernel_bind(sock
, (struct sockaddr
*) &udp6_addr
,
1429 udp6_addr
.sin6_family
= AF_INET6
;
1430 memcpy(&udp6_addr
.sin6_addr
, cfg
->peer_ip6
,
1431 sizeof(udp6_addr
.sin6_addr
));
1432 udp6_addr
.sin6_port
= htons(cfg
->peer_udp_port
);
1433 err
= kernel_connect(sock
,
1434 (struct sockaddr
*) &udp6_addr
,
1435 sizeof(udp6_addr
), 0);
1441 err
= sock_create_kern(AF_INET
, SOCK_DGRAM
, 0, &sock
);
1445 sk_change_net(sock
->sk
, net
);
1447 udp_addr
.sin_family
= AF_INET
;
1448 udp_addr
.sin_addr
= cfg
->local_ip
;
1449 udp_addr
.sin_port
= htons(cfg
->local_udp_port
);
1450 err
= kernel_bind(sock
, (struct sockaddr
*) &udp_addr
,
1455 udp_addr
.sin_family
= AF_INET
;
1456 udp_addr
.sin_addr
= cfg
->peer_ip
;
1457 udp_addr
.sin_port
= htons(cfg
->peer_udp_port
);
1458 err
= kernel_connect(sock
,
1459 (struct sockaddr
*) &udp_addr
,
1460 sizeof(udp_addr
), 0);
1465 if (!cfg
->use_udp_checksums
)
1466 sock
->sk
->sk_no_check
= UDP_CSUM_NOXMIT
;
1470 case L2TP_ENCAPTYPE_IP
:
1471 #if IS_ENABLED(CONFIG_IPV6)
1472 if (cfg
->local_ip6
&& cfg
->peer_ip6
) {
1473 err
= sock_create_kern(AF_INET6
, SOCK_DGRAM
,
1474 IPPROTO_L2TP
, &sock
);
1478 sk_change_net(sock
->sk
, net
);
1480 ip6_addr
.l2tp_family
= AF_INET6
;
1481 memcpy(&ip6_addr
.l2tp_addr
, cfg
->local_ip6
,
1482 sizeof(ip6_addr
.l2tp_addr
));
1483 ip6_addr
.l2tp_conn_id
= tunnel_id
;
1484 err
= kernel_bind(sock
, (struct sockaddr
*) &ip6_addr
,
1489 ip6_addr
.l2tp_family
= AF_INET6
;
1490 memcpy(&ip6_addr
.l2tp_addr
, cfg
->peer_ip6
,
1491 sizeof(ip6_addr
.l2tp_addr
));
1492 ip6_addr
.l2tp_conn_id
= peer_tunnel_id
;
1493 err
= kernel_connect(sock
,
1494 (struct sockaddr
*) &ip6_addr
,
1495 sizeof(ip6_addr
), 0);
1501 err
= sock_create_kern(AF_INET
, SOCK_DGRAM
,
1502 IPPROTO_L2TP
, &sock
);
1506 sk_change_net(sock
->sk
, net
);
1508 ip_addr
.l2tp_family
= AF_INET
;
1509 ip_addr
.l2tp_addr
= cfg
->local_ip
;
1510 ip_addr
.l2tp_conn_id
= tunnel_id
;
1511 err
= kernel_bind(sock
, (struct sockaddr
*) &ip_addr
,
1516 ip_addr
.l2tp_family
= AF_INET
;
1517 ip_addr
.l2tp_addr
= cfg
->peer_ip
;
1518 ip_addr
.l2tp_conn_id
= peer_tunnel_id
;
1519 err
= kernel_connect(sock
, (struct sockaddr
*) &ip_addr
,
1520 sizeof(ip_addr
), 0);
1532 if ((err
< 0) && sock
) {
1533 kernel_sock_shutdown(sock
, SHUT_RDWR
);
1534 sk_release_kernel(sock
->sk
);
1541 static struct lock_class_key l2tp_socket_class
;
1543 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
)
1545 struct l2tp_tunnel
*tunnel
= NULL
;
1547 struct socket
*sock
= NULL
;
1548 struct sock
*sk
= NULL
;
1549 struct l2tp_net
*pn
;
1550 enum l2tp_encap_type encap
= L2TP_ENCAPTYPE_UDP
;
1552 /* Get the tunnel socket from the fd, which was opened by
1553 * the userspace L2TP daemon. If not specified, create a
1557 err
= l2tp_tunnel_sock_create(net
, tunnel_id
, peer_tunnel_id
,
1562 sock
= sockfd_lookup(fd
, &err
);
1564 pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n",
1565 tunnel_id
, fd
, err
);
1570 /* Reject namespace mismatches */
1571 if (!net_eq(sock_net(sock
->sk
), net
)) {
1572 pr_err("tunl %u: netns mismatch\n", tunnel_id
);
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
= l2tp_tunnel(sk
);
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 #if IS_ENABLED(CONFIG_IPV6)
1634 if (sk
->sk_family
== PF_INET6
) {
1635 struct ipv6_pinfo
*np
= inet6_sk(sk
);
1637 if (ipv6_addr_v4mapped(&np
->saddr
) &&
1638 ipv6_addr_v4mapped(&sk
->sk_v6_daddr
)) {
1639 struct inet_sock
*inet
= inet_sk(sk
);
1641 tunnel
->v4mapped
= true;
1642 inet
->inet_saddr
= np
->saddr
.s6_addr32
[3];
1643 inet
->inet_rcv_saddr
= sk
->sk_v6_rcv_saddr
.s6_addr32
[3];
1644 inet
->inet_daddr
= sk
->sk_v6_daddr
.s6_addr32
[3];
1646 tunnel
->v4mapped
= false;
1651 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1652 tunnel
->encap
= encap
;
1653 if (encap
== L2TP_ENCAPTYPE_UDP
) {
1654 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1655 udp_sk(sk
)->encap_type
= UDP_ENCAP_L2TPINUDP
;
1656 udp_sk(sk
)->encap_rcv
= l2tp_udp_encap_recv
;
1657 udp_sk(sk
)->encap_destroy
= l2tp_udp_encap_destroy
;
1658 #if IS_ENABLED(CONFIG_IPV6)
1659 if (sk
->sk_family
== PF_INET6
&& !tunnel
->v4mapped
)
1660 udpv6_encap_enable();
1666 sk
->sk_user_data
= tunnel
;
1668 /* Hook on the tunnel socket destructor so that we can cleanup
1669 * if the tunnel socket goes away.
1671 tunnel
->old_sk_destruct
= sk
->sk_destruct
;
1672 sk
->sk_destruct
= &l2tp_tunnel_destruct
;
1675 lockdep_set_class_and_name(&sk
->sk_lock
.slock
, &l2tp_socket_class
, "l2tp_sock");
1677 sk
->sk_allocation
= GFP_ATOMIC
;
1679 /* Init delete workqueue struct */
1680 INIT_WORK(&tunnel
->del_work
, l2tp_tunnel_del_work
);
1682 /* Add tunnel to our list */
1683 INIT_LIST_HEAD(&tunnel
->list
);
1684 atomic_inc(&l2tp_tunnel_count
);
1686 /* Bump the reference count. The tunnel context is deleted
1687 * only when this drops to zero. Must be done before list insertion
1689 l2tp_tunnel_inc_refcount(tunnel
);
1690 spin_lock_bh(&pn
->l2tp_tunnel_list_lock
);
1691 list_add_rcu(&tunnel
->list
, &pn
->l2tp_tunnel_list
);
1692 spin_unlock_bh(&pn
->l2tp_tunnel_list_lock
);
1699 /* If tunnel's socket was created by the kernel, it doesn't
1702 if (sock
&& sock
->file
)
1707 EXPORT_SYMBOL_GPL(l2tp_tunnel_create
);
1709 /* This function is used by the netlink TUNNEL_DELETE command.
1711 int l2tp_tunnel_delete(struct l2tp_tunnel
*tunnel
)
1713 l2tp_tunnel_closeall(tunnel
);
1714 return (false == queue_work(l2tp_wq
, &tunnel
->del_work
));
1716 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete
);
1718 /* Really kill the session.
1720 void l2tp_session_free(struct l2tp_session
*session
)
1722 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1724 BUG_ON(atomic_read(&session
->ref_count
) != 0);
1727 BUG_ON(tunnel
->magic
!= L2TP_TUNNEL_MAGIC
);
1728 if (session
->session_id
!= 0)
1729 atomic_dec(&l2tp_session_count
);
1730 sock_put(tunnel
->sock
);
1731 session
->tunnel
= NULL
;
1732 l2tp_tunnel_dec_refcount(tunnel
);
1737 EXPORT_SYMBOL_GPL(l2tp_session_free
);
1739 /* Remove an l2tp session from l2tp_core's hash lists.
1740 * Provides a tidyup interface for pseudowire code which can't just route all
1741 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close
1744 void __l2tp_session_unhash(struct l2tp_session
*session
)
1746 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1748 /* Remove the session from core hashes */
1750 /* Remove from the per-tunnel hash */
1751 write_lock_bh(&tunnel
->hlist_lock
);
1752 hlist_del_init(&session
->hlist
);
1753 write_unlock_bh(&tunnel
->hlist_lock
);
1755 /* For L2TPv3 we have a per-net hash: remove from there, too */
1756 if (tunnel
->version
!= L2TP_HDR_VER_2
) {
1757 struct l2tp_net
*pn
= l2tp_pernet(tunnel
->l2tp_net
);
1758 spin_lock_bh(&pn
->l2tp_session_hlist_lock
);
1759 hlist_del_init_rcu(&session
->global_hlist
);
1760 spin_unlock_bh(&pn
->l2tp_session_hlist_lock
);
1765 EXPORT_SYMBOL_GPL(__l2tp_session_unhash
);
1767 /* This function is used by the netlink SESSION_DELETE command and by
1770 int l2tp_session_delete(struct l2tp_session
*session
)
1773 (*session
->ref
)(session
);
1774 __l2tp_session_unhash(session
);
1775 l2tp_session_queue_purge(session
);
1776 if (session
->session_close
!= NULL
)
1777 (*session
->session_close
)(session
);
1779 (*session
->deref
)(session
);
1780 l2tp_session_dec_refcount(session
);
1783 EXPORT_SYMBOL_GPL(l2tp_session_delete
);
1785 /* We come here whenever a session's send_seq, cookie_len or
1786 * l2specific_len parameters are set.
1788 void l2tp_session_set_header_len(struct l2tp_session
*session
, int version
)
1790 if (version
== L2TP_HDR_VER_2
) {
1791 session
->hdr_len
= 6;
1792 if (session
->send_seq
)
1793 session
->hdr_len
+= 4;
1795 session
->hdr_len
= 4 + session
->cookie_len
+ session
->l2specific_len
+ session
->offset
;
1796 if (session
->tunnel
->encap
== L2TP_ENCAPTYPE_UDP
)
1797 session
->hdr_len
+= 4;
1801 EXPORT_SYMBOL_GPL(l2tp_session_set_header_len
);
1803 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
)
1805 struct l2tp_session
*session
;
1807 session
= kzalloc(sizeof(struct l2tp_session
) + priv_size
, GFP_KERNEL
);
1808 if (session
!= NULL
) {
1809 session
->magic
= L2TP_SESSION_MAGIC
;
1810 session
->tunnel
= tunnel
;
1812 session
->session_id
= session_id
;
1813 session
->peer_session_id
= peer_session_id
;
1815 if (tunnel
->version
== L2TP_HDR_VER_2
)
1816 session
->nr_max
= 0xffff;
1818 session
->nr_max
= 0xffffff;
1819 session
->nr_window_size
= session
->nr_max
/ 2;
1820 session
->nr_oos_count_max
= 4;
1822 /* Use NR of first received packet */
1823 session
->reorder_skip
= 1;
1825 sprintf(&session
->name
[0], "sess %u/%u",
1826 tunnel
->tunnel_id
, session
->session_id
);
1828 skb_queue_head_init(&session
->reorder_q
);
1830 INIT_HLIST_NODE(&session
->hlist
);
1831 INIT_HLIST_NODE(&session
->global_hlist
);
1833 /* Inherit debug options from tunnel */
1834 session
->debug
= tunnel
->debug
;
1837 session
->pwtype
= cfg
->pw_type
;
1838 session
->debug
= cfg
->debug
;
1839 session
->mtu
= cfg
->mtu
;
1840 session
->mru
= cfg
->mru
;
1841 session
->send_seq
= cfg
->send_seq
;
1842 session
->recv_seq
= cfg
->recv_seq
;
1843 session
->lns_mode
= cfg
->lns_mode
;
1844 session
->reorder_timeout
= cfg
->reorder_timeout
;
1845 session
->offset
= cfg
->offset
;
1846 session
->l2specific_type
= cfg
->l2specific_type
;
1847 session
->l2specific_len
= cfg
->l2specific_len
;
1848 session
->cookie_len
= cfg
->cookie_len
;
1849 memcpy(&session
->cookie
[0], &cfg
->cookie
[0], cfg
->cookie_len
);
1850 session
->peer_cookie_len
= cfg
->peer_cookie_len
;
1851 memcpy(&session
->peer_cookie
[0], &cfg
->peer_cookie
[0], cfg
->peer_cookie_len
);
1854 if (tunnel
->version
== L2TP_HDR_VER_2
)
1855 session
->build_header
= l2tp_build_l2tpv2_header
;
1857 session
->build_header
= l2tp_build_l2tpv3_header
;
1859 l2tp_session_set_header_len(session
, tunnel
->version
);
1861 /* Bump the reference count. The session context is deleted
1862 * only when this drops to zero.
1864 l2tp_session_inc_refcount(session
);
1865 l2tp_tunnel_inc_refcount(tunnel
);
1867 /* Ensure tunnel socket isn't deleted */
1868 sock_hold(tunnel
->sock
);
1870 /* Add session to the tunnel's hash list */
1871 write_lock_bh(&tunnel
->hlist_lock
);
1872 hlist_add_head(&session
->hlist
,
1873 l2tp_session_id_hash(tunnel
, session_id
));
1874 write_unlock_bh(&tunnel
->hlist_lock
);
1876 /* And to the global session list if L2TPv3 */
1877 if (tunnel
->version
!= L2TP_HDR_VER_2
) {
1878 struct l2tp_net
*pn
= l2tp_pernet(tunnel
->l2tp_net
);
1880 spin_lock_bh(&pn
->l2tp_session_hlist_lock
);
1881 hlist_add_head_rcu(&session
->global_hlist
,
1882 l2tp_session_id_hash_2(pn
, session_id
));
1883 spin_unlock_bh(&pn
->l2tp_session_hlist_lock
);
1886 /* Ignore management session in session count value */
1887 if (session
->session_id
!= 0)
1888 atomic_inc(&l2tp_session_count
);
1893 EXPORT_SYMBOL_GPL(l2tp_session_create
);
1895 /*****************************************************************************
1897 *****************************************************************************/
1899 static __net_init
int l2tp_init_net(struct net
*net
)
1901 struct l2tp_net
*pn
= net_generic(net
, l2tp_net_id
);
1904 INIT_LIST_HEAD(&pn
->l2tp_tunnel_list
);
1905 spin_lock_init(&pn
->l2tp_tunnel_list_lock
);
1907 for (hash
= 0; hash
< L2TP_HASH_SIZE_2
; hash
++)
1908 INIT_HLIST_HEAD(&pn
->l2tp_session_hlist
[hash
]);
1910 spin_lock_init(&pn
->l2tp_session_hlist_lock
);
1915 static __net_exit
void l2tp_exit_net(struct net
*net
)
1917 struct l2tp_net
*pn
= l2tp_pernet(net
);
1918 struct l2tp_tunnel
*tunnel
= NULL
;
1921 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
1922 (void)l2tp_tunnel_delete(tunnel
);
1924 rcu_read_unlock_bh();
1927 static struct pernet_operations l2tp_net_ops
= {
1928 .init
= l2tp_init_net
,
1929 .exit
= l2tp_exit_net
,
1931 .size
= sizeof(struct l2tp_net
),
1934 static int __init
l2tp_init(void)
1938 rc
= register_pernet_device(&l2tp_net_ops
);
1942 l2tp_wq
= alloc_workqueue("l2tp", WQ_UNBOUND
, 0);
1944 pr_err("alloc_workqueue failed\n");
1949 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION
);
1955 static void __exit
l2tp_exit(void)
1957 unregister_pernet_device(&l2tp_net_ops
);
1959 destroy_workqueue(l2tp_wq
);
1964 module_init(l2tp_init
);
1965 module_exit(l2tp_exit
);
1967 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1968 MODULE_DESCRIPTION("L2TP core");
1969 MODULE_LICENSE("GPL");
1970 MODULE_VERSION(L2TP_DRV_VERSION
);