4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
6 * This file contains some code of the original L2TPv2 pppol2tp
7 * driver, which has the following copyright:
9 * Authors: Martijn van Oosterhout <kleptog@svana.org>
10 * James Chapman (jchapman@katalix.com)
12 * Michal Ostrowski <mostrows@speakeasy.net>
13 * Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
14 * David S. Miller (davem@redhat.com)
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License version 2 as
18 * published by the Free Software Foundation.
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/module.h>
24 #include <linux/string.h>
25 #include <linux/list.h>
26 #include <linux/rculist.h>
27 #include <linux/uaccess.h>
29 #include <linux/kernel.h>
30 #include <linux/spinlock.h>
31 #include <linux/kthread.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 #include <linux/errno.h>
35 #include <linux/jiffies.h>
37 #include <linux/netdevice.h>
38 #include <linux/net.h>
39 #include <linux/inetdevice.h>
40 #include <linux/skbuff.h>
41 #include <linux/init.h>
44 #include <linux/udp.h>
45 #include <linux/l2tp.h>
46 #include <linux/hash.h>
47 #include <linux/sort.h>
48 #include <linux/file.h>
49 #include <linux/nsproxy.h>
50 #include <net/net_namespace.h>
51 #include <net/netns/generic.h>
55 #include <net/udp_tunnel.h>
56 #include <net/inet_common.h>
58 #include <net/protocol.h>
59 #include <net/inet6_connection_sock.h>
60 #include <net/inet_ecn.h>
61 #include <net/ip6_route.h>
62 #include <net/ip6_checksum.h>
64 #include <asm/byteorder.h>
65 #include <linux/atomic.h>
67 #include "l2tp_core.h"
69 #define L2TP_DRV_VERSION "V2.0"
71 /* L2TP header constants */
72 #define L2TP_HDRFLAG_T 0x8000
73 #define L2TP_HDRFLAG_L 0x4000
74 #define L2TP_HDRFLAG_S 0x0800
75 #define L2TP_HDRFLAG_O 0x0200
76 #define L2TP_HDRFLAG_P 0x0100
78 #define L2TP_HDR_VER_MASK 0x000F
79 #define L2TP_HDR_VER_2 0x0002
80 #define L2TP_HDR_VER_3 0x0003
82 /* L2TPv3 default L2-specific sublayer */
83 #define L2TP_SLFLAG_S 0x40000000
84 #define L2TP_SL_SEQ_MASK 0x00ffffff
86 #define L2TP_HDR_SIZE_SEQ 10
87 #define L2TP_HDR_SIZE_NOSEQ 6
89 /* Default trace flags */
90 #define L2TP_DEFAULT_DEBUG_FLAGS 0
92 /* Private data stored for received packets in the skb.
98 unsigned long expires
;
101 #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
103 static struct workqueue_struct
*l2tp_wq
;
105 /* per-net private data for this module */
106 static unsigned int l2tp_net_id
;
108 struct list_head l2tp_tunnel_list
;
109 spinlock_t l2tp_tunnel_list_lock
;
110 struct hlist_head l2tp_session_hlist
[L2TP_HASH_SIZE_2
];
111 spinlock_t l2tp_session_hlist_lock
;
115 static inline struct l2tp_tunnel
*l2tp_tunnel(struct sock
*sk
)
117 return sk
->sk_user_data
;
120 static inline struct l2tp_net
*l2tp_pernet(const struct net
*net
)
124 return net_generic(net
, l2tp_net_id
);
127 /* Session hash global list for L2TPv3.
128 * The session_id SHOULD be random according to RFC3931, but several
129 * L2TP implementations use incrementing session_ids. So we do a real
130 * hash on the session_id, rather than a simple bitmask.
132 static inline struct hlist_head
*
133 l2tp_session_id_hash_2(struct l2tp_net
*pn
, u32 session_id
)
135 return &pn
->l2tp_session_hlist
[hash_32(session_id
, L2TP_HASH_BITS_2
)];
139 /* Session hash list.
140 * The session_id SHOULD be random according to RFC2661, but several
141 * L2TP implementations (Cisco and Microsoft) use incrementing
142 * session_ids. So we do a real hash on the session_id, rather than a
145 static inline struct hlist_head
*
146 l2tp_session_id_hash(struct l2tp_tunnel
*tunnel
, u32 session_id
)
148 return &tunnel
->session_hlist
[hash_32(session_id
, L2TP_HASH_BITS
)];
151 void l2tp_tunnel_free(struct l2tp_tunnel
*tunnel
)
153 sock_put(tunnel
->sock
);
154 /* the tunnel is freed in the socket destructor */
156 EXPORT_SYMBOL(l2tp_tunnel_free
);
158 /* Lookup a tunnel. A new reference is held on the returned tunnel. */
159 struct l2tp_tunnel
*l2tp_tunnel_get(const struct net
*net
, u32 tunnel_id
)
161 const struct l2tp_net
*pn
= l2tp_pernet(net
);
162 struct l2tp_tunnel
*tunnel
;
165 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
166 if (tunnel
->tunnel_id
== tunnel_id
) {
167 l2tp_tunnel_inc_refcount(tunnel
);
168 rcu_read_unlock_bh();
173 rcu_read_unlock_bh();
177 EXPORT_SYMBOL_GPL(l2tp_tunnel_get
);
179 /* Lookup a session. A new reference is held on the returned session. */
180 struct l2tp_session
*l2tp_session_get(const struct net
*net
,
181 struct l2tp_tunnel
*tunnel
,
184 struct hlist_head
*session_list
;
185 struct l2tp_session
*session
;
188 struct l2tp_net
*pn
= l2tp_pernet(net
);
190 session_list
= l2tp_session_id_hash_2(pn
, session_id
);
193 hlist_for_each_entry_rcu(session
, session_list
, global_hlist
) {
194 if (session
->session_id
== session_id
) {
195 l2tp_session_inc_refcount(session
);
196 rcu_read_unlock_bh();
201 rcu_read_unlock_bh();
206 session_list
= l2tp_session_id_hash(tunnel
, session_id
);
207 read_lock_bh(&tunnel
->hlist_lock
);
208 hlist_for_each_entry(session
, session_list
, hlist
) {
209 if (session
->session_id
== session_id
) {
210 l2tp_session_inc_refcount(session
);
211 read_unlock_bh(&tunnel
->hlist_lock
);
216 read_unlock_bh(&tunnel
->hlist_lock
);
220 EXPORT_SYMBOL_GPL(l2tp_session_get
);
222 struct l2tp_session
*l2tp_session_get_nth(struct l2tp_tunnel
*tunnel
, int nth
)
225 struct l2tp_session
*session
;
228 read_lock_bh(&tunnel
->hlist_lock
);
229 for (hash
= 0; hash
< L2TP_HASH_SIZE
; hash
++) {
230 hlist_for_each_entry(session
, &tunnel
->session_hlist
[hash
], hlist
) {
232 l2tp_session_inc_refcount(session
);
233 read_unlock_bh(&tunnel
->hlist_lock
);
239 read_unlock_bh(&tunnel
->hlist_lock
);
243 EXPORT_SYMBOL_GPL(l2tp_session_get_nth
);
245 /* Lookup a session by interface name.
246 * This is very inefficient but is only used by management interfaces.
248 struct l2tp_session
*l2tp_session_get_by_ifname(const struct net
*net
,
251 struct l2tp_net
*pn
= l2tp_pernet(net
);
253 struct l2tp_session
*session
;
256 for (hash
= 0; hash
< L2TP_HASH_SIZE_2
; hash
++) {
257 hlist_for_each_entry_rcu(session
, &pn
->l2tp_session_hlist
[hash
], global_hlist
) {
258 if (!strcmp(session
->ifname
, ifname
)) {
259 l2tp_session_inc_refcount(session
);
260 rcu_read_unlock_bh();
267 rcu_read_unlock_bh();
271 EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname
);
273 int l2tp_session_register(struct l2tp_session
*session
,
274 struct l2tp_tunnel
*tunnel
)
276 struct l2tp_session
*session_walk
;
277 struct hlist_head
*g_head
;
278 struct hlist_head
*head
;
282 head
= l2tp_session_id_hash(tunnel
, session
->session_id
);
284 write_lock_bh(&tunnel
->hlist_lock
);
285 if (!tunnel
->acpt_newsess
) {
290 hlist_for_each_entry(session_walk
, head
, hlist
)
291 if (session_walk
->session_id
== session
->session_id
) {
296 if (tunnel
->version
== L2TP_HDR_VER_3
) {
297 pn
= l2tp_pernet(tunnel
->l2tp_net
);
298 g_head
= l2tp_session_id_hash_2(l2tp_pernet(tunnel
->l2tp_net
),
299 session
->session_id
);
301 spin_lock_bh(&pn
->l2tp_session_hlist_lock
);
303 hlist_for_each_entry(session_walk
, g_head
, global_hlist
)
304 if (session_walk
->session_id
== session
->session_id
) {
306 goto err_tlock_pnlock
;
309 l2tp_tunnel_inc_refcount(tunnel
);
310 hlist_add_head_rcu(&session
->global_hlist
, g_head
);
312 spin_unlock_bh(&pn
->l2tp_session_hlist_lock
);
314 l2tp_tunnel_inc_refcount(tunnel
);
317 hlist_add_head(&session
->hlist
, head
);
318 write_unlock_bh(&tunnel
->hlist_lock
);
323 spin_unlock_bh(&pn
->l2tp_session_hlist_lock
);
325 write_unlock_bh(&tunnel
->hlist_lock
);
329 EXPORT_SYMBOL_GPL(l2tp_session_register
);
331 /* Lookup a tunnel by id
333 struct l2tp_tunnel
*l2tp_tunnel_find(const struct net
*net
, u32 tunnel_id
)
335 struct l2tp_tunnel
*tunnel
;
336 struct l2tp_net
*pn
= l2tp_pernet(net
);
339 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
340 if (tunnel
->tunnel_id
== tunnel_id
) {
341 rcu_read_unlock_bh();
345 rcu_read_unlock_bh();
349 EXPORT_SYMBOL_GPL(l2tp_tunnel_find
);
351 struct l2tp_tunnel
*l2tp_tunnel_find_nth(const struct net
*net
, int nth
)
353 struct l2tp_net
*pn
= l2tp_pernet(net
);
354 struct l2tp_tunnel
*tunnel
;
358 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
360 rcu_read_unlock_bh();
365 rcu_read_unlock_bh();
369 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth
);
371 /*****************************************************************************
372 * Receive data handling
373 *****************************************************************************/
375 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
378 static void l2tp_recv_queue_skb(struct l2tp_session
*session
, struct sk_buff
*skb
)
380 struct sk_buff
*skbp
;
382 u32 ns
= L2TP_SKB_CB(skb
)->ns
;
384 spin_lock_bh(&session
->reorder_q
.lock
);
385 skb_queue_walk_safe(&session
->reorder_q
, skbp
, tmp
) {
386 if (L2TP_SKB_CB(skbp
)->ns
> ns
) {
387 __skb_queue_before(&session
->reorder_q
, skbp
, skb
);
388 l2tp_dbg(session
, L2TP_MSG_SEQ
,
389 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
390 session
->name
, ns
, L2TP_SKB_CB(skbp
)->ns
,
391 skb_queue_len(&session
->reorder_q
));
392 atomic_long_inc(&session
->stats
.rx_oos_packets
);
397 __skb_queue_tail(&session
->reorder_q
, skb
);
400 spin_unlock_bh(&session
->reorder_q
.lock
);
403 /* Dequeue a single skb.
405 static void l2tp_recv_dequeue_skb(struct l2tp_session
*session
, struct sk_buff
*skb
)
407 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
408 int length
= L2TP_SKB_CB(skb
)->length
;
410 /* We're about to requeue the skb, so return resources
411 * to its current owner (a socket receive buffer).
415 atomic_long_inc(&tunnel
->stats
.rx_packets
);
416 atomic_long_add(length
, &tunnel
->stats
.rx_bytes
);
417 atomic_long_inc(&session
->stats
.rx_packets
);
418 atomic_long_add(length
, &session
->stats
.rx_bytes
);
420 if (L2TP_SKB_CB(skb
)->has_seq
) {
423 session
->nr
&= session
->nr_max
;
425 l2tp_dbg(session
, L2TP_MSG_SEQ
, "%s: updated nr to %hu\n",
426 session
->name
, session
->nr
);
429 /* call private receive handler */
430 if (session
->recv_skb
!= NULL
)
431 (*session
->recv_skb
)(session
, skb
, L2TP_SKB_CB(skb
)->length
);
436 /* Dequeue skbs from the session's reorder_q, subject to packet order.
437 * Skbs that have been in the queue for too long are simply discarded.
439 static void l2tp_recv_dequeue(struct l2tp_session
*session
)
444 /* If the pkt at the head of the queue has the nr that we
445 * expect to send up next, dequeue it and any other
446 * in-sequence packets behind it.
449 spin_lock_bh(&session
->reorder_q
.lock
);
450 skb_queue_walk_safe(&session
->reorder_q
, skb
, tmp
) {
451 if (time_after(jiffies
, L2TP_SKB_CB(skb
)->expires
)) {
452 atomic_long_inc(&session
->stats
.rx_seq_discards
);
453 atomic_long_inc(&session
->stats
.rx_errors
);
454 l2tp_dbg(session
, L2TP_MSG_SEQ
,
455 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
456 session
->name
, L2TP_SKB_CB(skb
)->ns
,
457 L2TP_SKB_CB(skb
)->length
, session
->nr
,
458 skb_queue_len(&session
->reorder_q
));
459 session
->reorder_skip
= 1;
460 __skb_unlink(skb
, &session
->reorder_q
);
465 if (L2TP_SKB_CB(skb
)->has_seq
) {
466 if (session
->reorder_skip
) {
467 l2tp_dbg(session
, L2TP_MSG_SEQ
,
468 "%s: advancing nr to next pkt: %u -> %u",
469 session
->name
, session
->nr
,
470 L2TP_SKB_CB(skb
)->ns
);
471 session
->reorder_skip
= 0;
472 session
->nr
= L2TP_SKB_CB(skb
)->ns
;
474 if (L2TP_SKB_CB(skb
)->ns
!= session
->nr
) {
475 l2tp_dbg(session
, L2TP_MSG_SEQ
,
476 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
477 session
->name
, L2TP_SKB_CB(skb
)->ns
,
478 L2TP_SKB_CB(skb
)->length
, session
->nr
,
479 skb_queue_len(&session
->reorder_q
));
483 __skb_unlink(skb
, &session
->reorder_q
);
485 /* Process the skb. We release the queue lock while we
486 * do so to let other contexts process the queue.
488 spin_unlock_bh(&session
->reorder_q
.lock
);
489 l2tp_recv_dequeue_skb(session
, skb
);
494 spin_unlock_bh(&session
->reorder_q
.lock
);
497 static int l2tp_seq_check_rx_window(struct l2tp_session
*session
, u32 nr
)
501 if (nr
>= session
->nr
)
502 nws
= nr
- session
->nr
;
504 nws
= (session
->nr_max
+ 1) - (session
->nr
- nr
);
506 return nws
< session
->nr_window_size
;
509 /* If packet has sequence numbers, queue it if acceptable. Returns 0 if
510 * acceptable, else non-zero.
512 static int l2tp_recv_data_seq(struct l2tp_session
*session
, struct sk_buff
*skb
)
514 if (!l2tp_seq_check_rx_window(session
, L2TP_SKB_CB(skb
)->ns
)) {
515 /* Packet sequence number is outside allowed window.
518 l2tp_dbg(session
, L2TP_MSG_SEQ
,
519 "%s: pkt %u len %d discarded, outside window, nr=%u\n",
520 session
->name
, L2TP_SKB_CB(skb
)->ns
,
521 L2TP_SKB_CB(skb
)->length
, session
->nr
);
525 if (session
->reorder_timeout
!= 0) {
526 /* Packet reordering enabled. Add skb to session's
527 * reorder queue, in order of ns.
529 l2tp_recv_queue_skb(session
, skb
);
533 /* Packet reordering disabled. Discard out-of-sequence packets, while
534 * tracking the number if in-sequence packets after the first OOS packet
535 * is seen. After nr_oos_count_max in-sequence packets, reset the
536 * sequence number to re-enable packet reception.
538 if (L2TP_SKB_CB(skb
)->ns
== session
->nr
) {
539 skb_queue_tail(&session
->reorder_q
, skb
);
541 u32 nr_oos
= L2TP_SKB_CB(skb
)->ns
;
542 u32 nr_next
= (session
->nr_oos
+ 1) & session
->nr_max
;
544 if (nr_oos
== nr_next
)
545 session
->nr_oos_count
++;
547 session
->nr_oos_count
= 0;
549 session
->nr_oos
= nr_oos
;
550 if (session
->nr_oos_count
> session
->nr_oos_count_max
) {
551 session
->reorder_skip
= 1;
552 l2tp_dbg(session
, L2TP_MSG_SEQ
,
553 "%s: %d oos packets received. Resetting sequence numbers\n",
554 session
->name
, session
->nr_oos_count
);
556 if (!session
->reorder_skip
) {
557 atomic_long_inc(&session
->stats
.rx_seq_discards
);
558 l2tp_dbg(session
, L2TP_MSG_SEQ
,
559 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
560 session
->name
, L2TP_SKB_CB(skb
)->ns
,
561 L2TP_SKB_CB(skb
)->length
, session
->nr
,
562 skb_queue_len(&session
->reorder_q
));
565 skb_queue_tail(&session
->reorder_q
, skb
);
575 /* Do receive processing of L2TP data frames. We handle both L2TPv2
576 * and L2TPv3 data frames here.
578 * L2TPv2 Data Message Header
581 * 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
582 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
583 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
584 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
585 * | Tunnel ID | Session ID |
586 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
587 * | Ns (opt) | Nr (opt) |
588 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
589 * | Offset Size (opt) | Offset pad... (opt)
590 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
592 * Data frames are marked by T=0. All other fields are the same as
593 * those in L2TP control frames.
595 * L2TPv3 Data Message Header
597 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
598 * | L2TP Session Header |
599 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
600 * | L2-Specific Sublayer |
601 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
602 * | Tunnel Payload ...
603 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
605 * L2TPv3 Session Header Over IP
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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
611 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
612 * | Cookie (optional, maximum 64 bits)...
613 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
615 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
617 * L2TPv3 L2-Specific Sublayer Format
620 * 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
621 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
622 * |x|S|x|x|x|x|x|x| Sequence Number |
623 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
625 * Cookie value, sublayer format and offset (pad) are negotiated with
626 * the peer when the session is set up. Unlike L2TPv2, we do not need
627 * to parse the packet header to determine if optional fields are
630 * Caller must already have parsed the frame and determined that it is
631 * a data (not control) frame before coming here. Fields up to the
632 * session-id have already been parsed and ptr points to the data
633 * after the session-id.
635 void l2tp_recv_common(struct l2tp_session
*session
, struct sk_buff
*skb
,
636 unsigned char *ptr
, unsigned char *optr
, u16 hdrflags
,
637 int length
, int (*payload_hook
)(struct sk_buff
*skb
))
639 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
643 /* Parse and check optional cookie */
644 if (session
->peer_cookie_len
> 0) {
645 if (memcmp(ptr
, &session
->peer_cookie
[0], session
->peer_cookie_len
)) {
646 l2tp_info(tunnel
, L2TP_MSG_DATA
,
647 "%s: cookie mismatch (%u/%u). Discarding.\n",
648 tunnel
->name
, tunnel
->tunnel_id
,
649 session
->session_id
);
650 atomic_long_inc(&session
->stats
.rx_cookie_discards
);
653 ptr
+= session
->peer_cookie_len
;
656 /* Handle the optional sequence numbers. Sequence numbers are
657 * in different places for L2TPv2 and L2TPv3.
659 * If we are the LAC, enable/disable sequence numbers under
660 * the control of the LNS. If no sequence numbers present but
661 * we were expecting them, discard frame.
664 L2TP_SKB_CB(skb
)->has_seq
= 0;
665 if (tunnel
->version
== L2TP_HDR_VER_2
) {
666 if (hdrflags
& L2TP_HDRFLAG_S
) {
667 ns
= ntohs(*(__be16
*) ptr
);
669 nr
= ntohs(*(__be16
*) ptr
);
672 /* Store L2TP info in the skb */
673 L2TP_SKB_CB(skb
)->ns
= ns
;
674 L2TP_SKB_CB(skb
)->has_seq
= 1;
676 l2tp_dbg(session
, L2TP_MSG_SEQ
,
677 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
678 session
->name
, ns
, nr
, session
->nr
);
680 } else if (session
->l2specific_type
== L2TP_L2SPECTYPE_DEFAULT
) {
681 u32 l2h
= ntohl(*(__be32
*) ptr
);
683 if (l2h
& 0x40000000) {
684 ns
= l2h
& 0x00ffffff;
686 /* Store L2TP info in the skb */
687 L2TP_SKB_CB(skb
)->ns
= ns
;
688 L2TP_SKB_CB(skb
)->has_seq
= 1;
690 l2tp_dbg(session
, L2TP_MSG_SEQ
,
691 "%s: recv data ns=%u, session nr=%u\n",
692 session
->name
, ns
, session
->nr
);
696 /* Advance past L2-specific header, if present */
697 ptr
+= session
->l2specific_len
;
699 if (L2TP_SKB_CB(skb
)->has_seq
) {
700 /* Received a packet with sequence numbers. If we're the LNS,
701 * check if we sre sending sequence numbers and if not,
704 if ((!session
->lns_mode
) && (!session
->send_seq
)) {
705 l2tp_info(session
, L2TP_MSG_SEQ
,
706 "%s: requested to enable seq numbers by LNS\n",
708 session
->send_seq
= 1;
709 l2tp_session_set_header_len(session
, tunnel
->version
);
712 /* No sequence numbers.
713 * If user has configured mandatory sequence numbers, discard.
715 if (session
->recv_seq
) {
716 l2tp_warn(session
, L2TP_MSG_SEQ
,
717 "%s: recv data has no seq numbers when required. Discarding.\n",
719 atomic_long_inc(&session
->stats
.rx_seq_discards
);
723 /* If we're the LAC and we're sending sequence numbers, the
724 * LNS has requested that we no longer send sequence numbers.
725 * If we're the LNS and we're sending sequence numbers, the
726 * LAC is broken. Discard the frame.
728 if ((!session
->lns_mode
) && (session
->send_seq
)) {
729 l2tp_info(session
, L2TP_MSG_SEQ
,
730 "%s: requested to disable seq numbers by LNS\n",
732 session
->send_seq
= 0;
733 l2tp_session_set_header_len(session
, tunnel
->version
);
734 } else if (session
->send_seq
) {
735 l2tp_warn(session
, L2TP_MSG_SEQ
,
736 "%s: recv data has no seq numbers when required. Discarding.\n",
738 atomic_long_inc(&session
->stats
.rx_seq_discards
);
743 /* Session data offset is handled differently for L2TPv2 and
744 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
745 * the header. For L2TPv3, the offset is negotiated using AVPs
746 * in the session setup control protocol.
748 if (tunnel
->version
== L2TP_HDR_VER_2
) {
749 /* If offset bit set, skip it. */
750 if (hdrflags
& L2TP_HDRFLAG_O
) {
751 offset
= ntohs(*(__be16
*)ptr
);
755 ptr
+= session
->offset
;
758 if (!pskb_may_pull(skb
, offset
))
761 __skb_pull(skb
, offset
);
763 /* If caller wants to process the payload before we queue the
767 if ((*payload_hook
)(skb
))
770 /* Prepare skb for adding to the session's reorder_q. Hold
771 * packets for max reorder_timeout or 1 second if not
774 L2TP_SKB_CB(skb
)->length
= length
;
775 L2TP_SKB_CB(skb
)->expires
= jiffies
+
776 (session
->reorder_timeout
? session
->reorder_timeout
: HZ
);
778 /* Add packet to the session's receive queue. Reordering is done here, if
779 * enabled. Saved L2TP protocol info is stored in skb->sb[].
781 if (L2TP_SKB_CB(skb
)->has_seq
) {
782 if (l2tp_recv_data_seq(session
, skb
))
785 /* No sequence numbers. Add the skb to the tail of the
786 * reorder queue. This ensures that it will be
787 * delivered after all previous sequenced skbs.
789 skb_queue_tail(&session
->reorder_q
, skb
);
792 /* Try to dequeue as many skbs from reorder_q as we can. */
793 l2tp_recv_dequeue(session
);
798 atomic_long_inc(&session
->stats
.rx_errors
);
801 EXPORT_SYMBOL(l2tp_recv_common
);
803 /* Drop skbs from the session's reorder_q
805 int l2tp_session_queue_purge(struct l2tp_session
*session
)
807 struct sk_buff
*skb
= NULL
;
809 BUG_ON(session
->magic
!= L2TP_SESSION_MAGIC
);
810 while ((skb
= skb_dequeue(&session
->reorder_q
))) {
811 atomic_long_inc(&session
->stats
.rx_errors
);
816 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge
);
818 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
819 * here. The skb is not on a list when we get here.
820 * Returns 0 if the packet was a data packet and was successfully passed on.
821 * Returns 1 if the packet was not a good data packet and could not be
822 * forwarded. All such packets are passed up to userspace to deal with.
824 static int l2tp_udp_recv_core(struct l2tp_tunnel
*tunnel
, struct sk_buff
*skb
,
825 int (*payload_hook
)(struct sk_buff
*skb
))
827 struct l2tp_session
*session
= NULL
;
828 unsigned char *ptr
, *optr
;
830 u32 tunnel_id
, session_id
;
834 /* UDP has verifed checksum */
836 /* UDP always verifies the packet length. */
837 __skb_pull(skb
, sizeof(struct udphdr
));
840 if (!pskb_may_pull(skb
, L2TP_HDR_SIZE_SEQ
)) {
841 l2tp_info(tunnel
, L2TP_MSG_DATA
,
842 "%s: recv short packet (len=%d)\n",
843 tunnel
->name
, skb
->len
);
847 /* Trace packet contents, if enabled */
848 if (tunnel
->debug
& L2TP_MSG_DATA
) {
849 length
= min(32u, skb
->len
);
850 if (!pskb_may_pull(skb
, length
))
853 pr_debug("%s: recv\n", tunnel
->name
);
854 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET
, skb
->data
, length
);
857 /* Point to L2TP header */
858 optr
= ptr
= skb
->data
;
860 /* Get L2TP header flags */
861 hdrflags
= ntohs(*(__be16
*) ptr
);
863 /* Check protocol version */
864 version
= hdrflags
& L2TP_HDR_VER_MASK
;
865 if (version
!= tunnel
->version
) {
866 l2tp_info(tunnel
, L2TP_MSG_DATA
,
867 "%s: recv protocol version mismatch: got %d expected %d\n",
868 tunnel
->name
, version
, tunnel
->version
);
872 /* Get length of L2TP packet */
875 /* If type is control packet, it is handled by userspace. */
876 if (hdrflags
& L2TP_HDRFLAG_T
) {
877 l2tp_dbg(tunnel
, L2TP_MSG_DATA
,
878 "%s: recv control packet, len=%d\n",
879 tunnel
->name
, length
);
886 if (tunnel
->version
== L2TP_HDR_VER_2
) {
887 /* If length is present, skip it */
888 if (hdrflags
& L2TP_HDRFLAG_L
)
891 /* Extract tunnel and session ID */
892 tunnel_id
= ntohs(*(__be16
*) ptr
);
894 session_id
= ntohs(*(__be16
*) ptr
);
897 ptr
+= 2; /* skip reserved bits */
898 tunnel_id
= tunnel
->tunnel_id
;
899 session_id
= ntohl(*(__be32
*) ptr
);
903 /* Find the session context */
904 session
= l2tp_session_get(tunnel
->l2tp_net
, tunnel
, session_id
);
905 if (!session
|| !session
->recv_skb
) {
907 l2tp_session_dec_refcount(session
);
909 /* Not found? Pass to userspace to deal with */
910 l2tp_info(tunnel
, L2TP_MSG_DATA
,
911 "%s: no session found (%u/%u). Passing up.\n",
912 tunnel
->name
, tunnel_id
, session_id
);
916 l2tp_recv_common(session
, skb
, ptr
, optr
, hdrflags
, length
, payload_hook
);
917 l2tp_session_dec_refcount(session
);
922 /* Put UDP header back */
923 __skb_push(skb
, sizeof(struct udphdr
));
928 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
932 * >0: skb should be passed up to userspace as UDP.
934 int l2tp_udp_encap_recv(struct sock
*sk
, struct sk_buff
*skb
)
936 struct l2tp_tunnel
*tunnel
;
938 tunnel
= l2tp_tunnel(sk
);
942 l2tp_dbg(tunnel
, L2TP_MSG_DATA
, "%s: received %d bytes\n",
943 tunnel
->name
, skb
->len
);
945 if (l2tp_udp_recv_core(tunnel
, skb
, tunnel
->recv_payload_hook
))
953 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv
);
955 /************************************************************************
957 ***********************************************************************/
959 /* Build an L2TP header for the session into the buffer provided.
961 static int l2tp_build_l2tpv2_header(struct l2tp_session
*session
, void *buf
)
963 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
966 u16 flags
= L2TP_HDR_VER_2
;
967 u32 tunnel_id
= tunnel
->peer_tunnel_id
;
968 u32 session_id
= session
->peer_session_id
;
970 if (session
->send_seq
)
971 flags
|= L2TP_HDRFLAG_S
;
973 /* Setup L2TP header. */
974 *bufp
++ = htons(flags
);
975 *bufp
++ = htons(tunnel_id
);
976 *bufp
++ = htons(session_id
);
977 if (session
->send_seq
) {
978 *bufp
++ = htons(session
->ns
);
981 session
->ns
&= 0xffff;
982 l2tp_dbg(session
, L2TP_MSG_SEQ
, "%s: updated ns to %u\n",
983 session
->name
, session
->ns
);
989 static int l2tp_build_l2tpv3_header(struct l2tp_session
*session
, void *buf
)
991 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
995 /* Setup L2TP header. The header differs slightly for UDP and
996 * IP encapsulations. For UDP, there is 4 bytes of flags.
998 if (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) {
999 u16 flags
= L2TP_HDR_VER_3
;
1000 *((__be16
*) bufp
) = htons(flags
);
1002 *((__be16
*) bufp
) = 0;
1006 *((__be32
*) bufp
) = htonl(session
->peer_session_id
);
1008 if (session
->cookie_len
) {
1009 memcpy(bufp
, &session
->cookie
[0], session
->cookie_len
);
1010 bufp
+= session
->cookie_len
;
1012 if (session
->l2specific_len
) {
1013 if (session
->l2specific_type
== L2TP_L2SPECTYPE_DEFAULT
) {
1015 if (session
->send_seq
) {
1016 l2h
= 0x40000000 | session
->ns
;
1018 session
->ns
&= 0xffffff;
1019 l2tp_dbg(session
, L2TP_MSG_SEQ
,
1020 "%s: updated ns to %u\n",
1021 session
->name
, session
->ns
);
1024 *((__be32
*) bufp
) = htonl(l2h
);
1026 bufp
+= session
->l2specific_len
;
1028 if (session
->offset
)
1029 bufp
+= session
->offset
;
1034 static int l2tp_xmit_core(struct l2tp_session
*session
, struct sk_buff
*skb
,
1035 struct flowi
*fl
, size_t data_len
)
1037 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1038 unsigned int len
= skb
->len
;
1042 if (session
->send_seq
)
1043 l2tp_dbg(session
, L2TP_MSG_DATA
, "%s: send %zd bytes, ns=%u\n",
1044 session
->name
, data_len
, session
->ns
- 1);
1046 l2tp_dbg(session
, L2TP_MSG_DATA
, "%s: send %zd bytes\n",
1047 session
->name
, data_len
);
1049 if (session
->debug
& L2TP_MSG_DATA
) {
1050 int uhlen
= (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) ? sizeof(struct udphdr
) : 0;
1051 unsigned char *datap
= skb
->data
+ uhlen
;
1053 pr_debug("%s: xmit\n", session
->name
);
1054 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET
,
1055 datap
, min_t(size_t, 32, len
- uhlen
));
1058 /* Queue the packet to IP for output */
1060 #if IS_ENABLED(CONFIG_IPV6)
1061 if (tunnel
->sock
->sk_family
== PF_INET6
&& !tunnel
->v4mapped
)
1062 error
= inet6_csk_xmit(tunnel
->sock
, skb
, NULL
);
1065 error
= ip_queue_xmit(tunnel
->sock
, skb
, fl
);
1069 atomic_long_inc(&tunnel
->stats
.tx_packets
);
1070 atomic_long_add(len
, &tunnel
->stats
.tx_bytes
);
1071 atomic_long_inc(&session
->stats
.tx_packets
);
1072 atomic_long_add(len
, &session
->stats
.tx_bytes
);
1074 atomic_long_inc(&tunnel
->stats
.tx_errors
);
1075 atomic_long_inc(&session
->stats
.tx_errors
);
1081 /* If caller requires the skb to have a ppp header, the header must be
1082 * inserted in the skb data before calling this function.
1084 int l2tp_xmit_skb(struct l2tp_session
*session
, struct sk_buff
*skb
, int hdr_len
)
1086 int data_len
= skb
->len
;
1087 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1088 struct sock
*sk
= tunnel
->sock
;
1091 struct inet_sock
*inet
;
1093 int uhlen
= (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) ? sizeof(struct udphdr
) : 0;
1095 int ret
= NET_XMIT_SUCCESS
;
1097 /* Check that there's enough headroom in the skb to insert IP,
1098 * UDP and L2TP headers. If not enough, expand it to
1099 * make room. Adjust truesize.
1101 headroom
= NET_SKB_PAD
+ sizeof(struct iphdr
) +
1103 if (skb_cow_head(skb
, headroom
)) {
1105 return NET_XMIT_DROP
;
1108 /* Setup L2TP header */
1109 session
->build_header(session
, __skb_push(skb
, hdr_len
));
1111 /* Reset skb netfilter state */
1112 memset(&(IPCB(skb
)->opt
), 0, sizeof(IPCB(skb
)->opt
));
1113 IPCB(skb
)->flags
&= ~(IPSKB_XFRM_TUNNEL_SIZE
| IPSKB_XFRM_TRANSFORMED
|
1118 if (sock_owned_by_user(sk
)) {
1120 ret
= NET_XMIT_DROP
;
1124 /* Get routing info from the tunnel socket */
1126 skb_dst_set(skb
, dst_clone(__sk_dst_check(sk
, 0)));
1129 fl
= &inet
->cork
.fl
;
1130 switch (tunnel
->encap
) {
1131 case L2TP_ENCAPTYPE_UDP
:
1132 /* Setup UDP header */
1133 __skb_push(skb
, sizeof(*uh
));
1134 skb_reset_transport_header(skb
);
1136 uh
->source
= inet
->inet_sport
;
1137 uh
->dest
= inet
->inet_dport
;
1138 udp_len
= uhlen
+ hdr_len
+ data_len
;
1139 uh
->len
= htons(udp_len
);
1141 /* Calculate UDP checksum if configured to do so */
1142 #if IS_ENABLED(CONFIG_IPV6)
1143 if (sk
->sk_family
== PF_INET6
&& !tunnel
->v4mapped
)
1144 udp6_set_csum(udp_get_no_check6_tx(sk
),
1145 skb
, &inet6_sk(sk
)->saddr
,
1146 &sk
->sk_v6_daddr
, udp_len
);
1149 udp_set_csum(sk
->sk_no_check_tx
, skb
, inet
->inet_saddr
,
1150 inet
->inet_daddr
, udp_len
);
1153 case L2TP_ENCAPTYPE_IP
:
1157 l2tp_xmit_core(session
, skb
, fl
, data_len
);
1163 EXPORT_SYMBOL_GPL(l2tp_xmit_skb
);
1165 /*****************************************************************************
1166 * Tinnel and session create/destroy.
1167 *****************************************************************************/
1169 /* Tunnel socket destruct hook.
1170 * The tunnel context is deleted only when all session sockets have been
1173 static void l2tp_tunnel_destruct(struct sock
*sk
)
1175 struct l2tp_tunnel
*tunnel
= l2tp_tunnel(sk
);
1180 l2tp_info(tunnel
, L2TP_MSG_CONTROL
, "%s: closing...\n", tunnel
->name
);
1182 /* Disable udp encapsulation */
1183 switch (tunnel
->encap
) {
1184 case L2TP_ENCAPTYPE_UDP
:
1185 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1186 (udp_sk(sk
))->encap_type
= 0;
1187 (udp_sk(sk
))->encap_rcv
= NULL
;
1188 (udp_sk(sk
))->encap_destroy
= NULL
;
1190 case L2TP_ENCAPTYPE_IP
:
1194 /* Remove hooks into tunnel socket */
1195 sk
->sk_destruct
= tunnel
->old_sk_destruct
;
1196 sk
->sk_user_data
= NULL
;
1198 /* Call the original destructor */
1199 if (sk
->sk_destruct
)
1200 (*sk
->sk_destruct
)(sk
);
1202 kfree_rcu(tunnel
, rcu
);
1207 /* When the tunnel is closed, all the attached sessions need to go too.
1209 void l2tp_tunnel_closeall(struct l2tp_tunnel
*tunnel
)
1212 struct hlist_node
*walk
;
1213 struct hlist_node
*tmp
;
1214 struct l2tp_session
*session
;
1216 BUG_ON(tunnel
== NULL
);
1218 l2tp_info(tunnel
, L2TP_MSG_CONTROL
, "%s: closing all sessions...\n",
1221 write_lock_bh(&tunnel
->hlist_lock
);
1222 tunnel
->acpt_newsess
= false;
1223 for (hash
= 0; hash
< L2TP_HASH_SIZE
; hash
++) {
1225 hlist_for_each_safe(walk
, tmp
, &tunnel
->session_hlist
[hash
]) {
1226 session
= hlist_entry(walk
, struct l2tp_session
, hlist
);
1228 l2tp_info(session
, L2TP_MSG_CONTROL
,
1229 "%s: closing session\n", session
->name
);
1231 hlist_del_init(&session
->hlist
);
1233 if (test_and_set_bit(0, &session
->dead
))
1236 write_unlock_bh(&tunnel
->hlist_lock
);
1238 __l2tp_session_unhash(session
);
1239 l2tp_session_queue_purge(session
);
1241 if (session
->session_close
!= NULL
)
1242 (*session
->session_close
)(session
);
1244 l2tp_session_dec_refcount(session
);
1246 write_lock_bh(&tunnel
->hlist_lock
);
1248 /* Now restart from the beginning of this hash
1249 * chain. We always remove a session from the
1250 * list so we are guaranteed to make forward
1256 write_unlock_bh(&tunnel
->hlist_lock
);
1258 EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall
);
1260 /* Tunnel socket destroy hook for UDP encapsulation */
1261 static void l2tp_udp_encap_destroy(struct sock
*sk
)
1263 struct l2tp_tunnel
*tunnel
= l2tp_tunnel(sk
);
1266 l2tp_tunnel_delete(tunnel
);
1269 /* Workqueue tunnel deletion function */
1270 static void l2tp_tunnel_del_work(struct work_struct
*work
)
1272 struct l2tp_tunnel
*tunnel
= container_of(work
, struct l2tp_tunnel
,
1274 struct sock
*sk
= tunnel
->sock
;
1275 struct socket
*sock
= sk
->sk_socket
;
1276 struct l2tp_net
*pn
;
1278 l2tp_tunnel_closeall(tunnel
);
1280 /* If the tunnel socket was created within the kernel, use
1281 * the sk API to release it here.
1283 if (tunnel
->fd
< 0) {
1285 kernel_sock_shutdown(sock
, SHUT_RDWR
);
1290 /* Remove the tunnel struct from the tunnel list */
1291 pn
= l2tp_pernet(tunnel
->l2tp_net
);
1292 spin_lock_bh(&pn
->l2tp_tunnel_list_lock
);
1293 list_del_rcu(&tunnel
->list
);
1294 spin_unlock_bh(&pn
->l2tp_tunnel_list_lock
);
1296 /* drop initial ref */
1297 l2tp_tunnel_dec_refcount(tunnel
);
1299 /* drop workqueue ref */
1300 l2tp_tunnel_dec_refcount(tunnel
);
1303 /* Create a socket for the tunnel, if one isn't set up by
1304 * userspace. This is used for static tunnels where there is no
1305 * managing L2TP daemon.
1307 * Since we don't want these sockets to keep a namespace alive by
1308 * themselves, we drop the socket's namespace refcount after creation.
1309 * These sockets are freed when the namespace exits using the pernet
1312 static int l2tp_tunnel_sock_create(struct net
*net
,
1315 struct l2tp_tunnel_cfg
*cfg
,
1316 struct socket
**sockp
)
1319 struct socket
*sock
= NULL
;
1320 struct udp_port_cfg udp_conf
;
1322 switch (cfg
->encap
) {
1323 case L2TP_ENCAPTYPE_UDP
:
1324 memset(&udp_conf
, 0, sizeof(udp_conf
));
1326 #if IS_ENABLED(CONFIG_IPV6)
1327 if (cfg
->local_ip6
&& cfg
->peer_ip6
) {
1328 udp_conf
.family
= AF_INET6
;
1329 memcpy(&udp_conf
.local_ip6
, cfg
->local_ip6
,
1330 sizeof(udp_conf
.local_ip6
));
1331 memcpy(&udp_conf
.peer_ip6
, cfg
->peer_ip6
,
1332 sizeof(udp_conf
.peer_ip6
));
1333 udp_conf
.use_udp6_tx_checksums
=
1334 ! cfg
->udp6_zero_tx_checksums
;
1335 udp_conf
.use_udp6_rx_checksums
=
1336 ! cfg
->udp6_zero_rx_checksums
;
1340 udp_conf
.family
= AF_INET
;
1341 udp_conf
.local_ip
= cfg
->local_ip
;
1342 udp_conf
.peer_ip
= cfg
->peer_ip
;
1343 udp_conf
.use_udp_checksums
= cfg
->use_udp_checksums
;
1346 udp_conf
.local_udp_port
= htons(cfg
->local_udp_port
);
1347 udp_conf
.peer_udp_port
= htons(cfg
->peer_udp_port
);
1349 err
= udp_sock_create(net
, &udp_conf
, &sock
);
1355 case L2TP_ENCAPTYPE_IP
:
1356 #if IS_ENABLED(CONFIG_IPV6)
1357 if (cfg
->local_ip6
&& cfg
->peer_ip6
) {
1358 struct sockaddr_l2tpip6 ip6_addr
= {0};
1360 err
= sock_create_kern(net
, AF_INET6
, SOCK_DGRAM
,
1361 IPPROTO_L2TP
, &sock
);
1365 ip6_addr
.l2tp_family
= AF_INET6
;
1366 memcpy(&ip6_addr
.l2tp_addr
, cfg
->local_ip6
,
1367 sizeof(ip6_addr
.l2tp_addr
));
1368 ip6_addr
.l2tp_conn_id
= tunnel_id
;
1369 err
= kernel_bind(sock
, (struct sockaddr
*) &ip6_addr
,
1374 ip6_addr
.l2tp_family
= AF_INET6
;
1375 memcpy(&ip6_addr
.l2tp_addr
, cfg
->peer_ip6
,
1376 sizeof(ip6_addr
.l2tp_addr
));
1377 ip6_addr
.l2tp_conn_id
= peer_tunnel_id
;
1378 err
= kernel_connect(sock
,
1379 (struct sockaddr
*) &ip6_addr
,
1380 sizeof(ip6_addr
), 0);
1386 struct sockaddr_l2tpip ip_addr
= {0};
1388 err
= sock_create_kern(net
, AF_INET
, SOCK_DGRAM
,
1389 IPPROTO_L2TP
, &sock
);
1393 ip_addr
.l2tp_family
= AF_INET
;
1394 ip_addr
.l2tp_addr
= cfg
->local_ip
;
1395 ip_addr
.l2tp_conn_id
= tunnel_id
;
1396 err
= kernel_bind(sock
, (struct sockaddr
*) &ip_addr
,
1401 ip_addr
.l2tp_family
= AF_INET
;
1402 ip_addr
.l2tp_addr
= cfg
->peer_ip
;
1403 ip_addr
.l2tp_conn_id
= peer_tunnel_id
;
1404 err
= kernel_connect(sock
, (struct sockaddr
*) &ip_addr
,
1405 sizeof(ip_addr
), 0);
1417 if ((err
< 0) && sock
) {
1418 kernel_sock_shutdown(sock
, SHUT_RDWR
);
1426 static struct lock_class_key l2tp_socket_class
;
1428 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
)
1430 struct l2tp_tunnel
*tunnel
= NULL
;
1432 struct socket
*sock
= NULL
;
1433 struct sock
*sk
= NULL
;
1434 struct l2tp_net
*pn
;
1435 enum l2tp_encap_type encap
= L2TP_ENCAPTYPE_UDP
;
1437 /* Get the tunnel socket from the fd, which was opened by
1438 * the userspace L2TP daemon. If not specified, create a
1442 err
= l2tp_tunnel_sock_create(net
, tunnel_id
, peer_tunnel_id
,
1447 sock
= sockfd_lookup(fd
, &err
);
1449 pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n",
1450 tunnel_id
, fd
, err
);
1455 /* Reject namespace mismatches */
1456 if (!net_eq(sock_net(sock
->sk
), net
)) {
1457 pr_err("tunl %u: netns mismatch\n", tunnel_id
);
1468 /* Quick sanity checks */
1469 err
= -EPROTONOSUPPORT
;
1470 if (sk
->sk_type
!= SOCK_DGRAM
) {
1471 pr_debug("tunl %hu: fd %d wrong socket type\n",
1476 case L2TP_ENCAPTYPE_UDP
:
1477 if (sk
->sk_protocol
!= IPPROTO_UDP
) {
1478 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1479 tunnel_id
, fd
, sk
->sk_protocol
, IPPROTO_UDP
);
1483 case L2TP_ENCAPTYPE_IP
:
1484 if (sk
->sk_protocol
!= IPPROTO_L2TP
) {
1485 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1486 tunnel_id
, fd
, sk
->sk_protocol
, IPPROTO_L2TP
);
1492 /* Check if this socket has already been prepped */
1493 tunnel
= l2tp_tunnel(sk
);
1494 if (tunnel
!= NULL
) {
1495 /* This socket has already been prepped */
1500 tunnel
= kzalloc(sizeof(struct l2tp_tunnel
), GFP_KERNEL
);
1501 if (tunnel
== NULL
) {
1506 tunnel
->version
= version
;
1507 tunnel
->tunnel_id
= tunnel_id
;
1508 tunnel
->peer_tunnel_id
= peer_tunnel_id
;
1509 tunnel
->debug
= L2TP_DEFAULT_DEBUG_FLAGS
;
1511 tunnel
->magic
= L2TP_TUNNEL_MAGIC
;
1512 sprintf(&tunnel
->name
[0], "tunl %u", tunnel_id
);
1513 rwlock_init(&tunnel
->hlist_lock
);
1514 tunnel
->acpt_newsess
= true;
1516 /* The net we belong to */
1517 tunnel
->l2tp_net
= net
;
1518 pn
= l2tp_pernet(net
);
1521 tunnel
->debug
= cfg
->debug
;
1523 #if IS_ENABLED(CONFIG_IPV6)
1524 if (sk
->sk_family
== PF_INET6
) {
1525 struct ipv6_pinfo
*np
= inet6_sk(sk
);
1527 if (ipv6_addr_v4mapped(&np
->saddr
) &&
1528 ipv6_addr_v4mapped(&sk
->sk_v6_daddr
)) {
1529 struct inet_sock
*inet
= inet_sk(sk
);
1531 tunnel
->v4mapped
= true;
1532 inet
->inet_saddr
= np
->saddr
.s6_addr32
[3];
1533 inet
->inet_rcv_saddr
= sk
->sk_v6_rcv_saddr
.s6_addr32
[3];
1534 inet
->inet_daddr
= sk
->sk_v6_daddr
.s6_addr32
[3];
1536 tunnel
->v4mapped
= false;
1541 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1542 tunnel
->encap
= encap
;
1543 if (encap
== L2TP_ENCAPTYPE_UDP
) {
1544 struct udp_tunnel_sock_cfg udp_cfg
= { };
1546 udp_cfg
.sk_user_data
= tunnel
;
1547 udp_cfg
.encap_type
= UDP_ENCAP_L2TPINUDP
;
1548 udp_cfg
.encap_rcv
= l2tp_udp_encap_recv
;
1549 udp_cfg
.encap_destroy
= l2tp_udp_encap_destroy
;
1551 setup_udp_tunnel_sock(net
, sock
, &udp_cfg
);
1553 sk
->sk_user_data
= tunnel
;
1556 /* Bump the reference count. The tunnel context is deleted
1557 * only when this drops to zero. A reference is also held on
1558 * the tunnel socket to ensure that it is not released while
1559 * the tunnel is extant. Must be done before sk_destruct is
1562 refcount_set(&tunnel
->ref_count
, 1);
1567 /* Hook on the tunnel socket destructor so that we can cleanup
1568 * if the tunnel socket goes away.
1570 tunnel
->old_sk_destruct
= sk
->sk_destruct
;
1571 sk
->sk_destruct
= &l2tp_tunnel_destruct
;
1572 lockdep_set_class_and_name(&sk
->sk_lock
.slock
, &l2tp_socket_class
, "l2tp_sock");
1574 sk
->sk_allocation
= GFP_ATOMIC
;
1576 /* Init delete workqueue struct */
1577 INIT_WORK(&tunnel
->del_work
, l2tp_tunnel_del_work
);
1579 /* Add tunnel to our list */
1580 INIT_LIST_HEAD(&tunnel
->list
);
1581 spin_lock_bh(&pn
->l2tp_tunnel_list_lock
);
1582 list_add_rcu(&tunnel
->list
, &pn
->l2tp_tunnel_list
);
1583 spin_unlock_bh(&pn
->l2tp_tunnel_list_lock
);
1590 /* If tunnel's socket was created by the kernel, it doesn't
1593 if (sock
&& sock
->file
)
1598 EXPORT_SYMBOL_GPL(l2tp_tunnel_create
);
1600 /* This function is used by the netlink TUNNEL_DELETE command.
1602 void l2tp_tunnel_delete(struct l2tp_tunnel
*tunnel
)
1604 if (!test_and_set_bit(0, &tunnel
->dead
)) {
1605 l2tp_tunnel_inc_refcount(tunnel
);
1606 queue_work(l2tp_wq
, &tunnel
->del_work
);
1609 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete
);
1611 /* Really kill the session.
1613 void l2tp_session_free(struct l2tp_session
*session
)
1615 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1617 BUG_ON(refcount_read(&session
->ref_count
) != 0);
1620 BUG_ON(tunnel
->magic
!= L2TP_TUNNEL_MAGIC
);
1621 l2tp_tunnel_dec_refcount(tunnel
);
1626 EXPORT_SYMBOL_GPL(l2tp_session_free
);
1628 /* Remove an l2tp session from l2tp_core's hash lists.
1629 * Provides a tidyup interface for pseudowire code which can't just route all
1630 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close
1633 void __l2tp_session_unhash(struct l2tp_session
*session
)
1635 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1637 /* Remove the session from core hashes */
1639 /* Remove from the per-tunnel hash */
1640 write_lock_bh(&tunnel
->hlist_lock
);
1641 hlist_del_init(&session
->hlist
);
1642 write_unlock_bh(&tunnel
->hlist_lock
);
1644 /* For L2TPv3 we have a per-net hash: remove from there, too */
1645 if (tunnel
->version
!= L2TP_HDR_VER_2
) {
1646 struct l2tp_net
*pn
= l2tp_pernet(tunnel
->l2tp_net
);
1647 spin_lock_bh(&pn
->l2tp_session_hlist_lock
);
1648 hlist_del_init_rcu(&session
->global_hlist
);
1649 spin_unlock_bh(&pn
->l2tp_session_hlist_lock
);
1654 EXPORT_SYMBOL_GPL(__l2tp_session_unhash
);
1656 /* This function is used by the netlink SESSION_DELETE command and by
1659 int l2tp_session_delete(struct l2tp_session
*session
)
1661 if (test_and_set_bit(0, &session
->dead
))
1664 __l2tp_session_unhash(session
);
1665 l2tp_session_queue_purge(session
);
1666 if (session
->session_close
!= NULL
)
1667 (*session
->session_close
)(session
);
1669 l2tp_session_dec_refcount(session
);
1673 EXPORT_SYMBOL_GPL(l2tp_session_delete
);
1675 /* We come here whenever a session's send_seq, cookie_len or
1676 * l2specific_len parameters are set.
1678 void l2tp_session_set_header_len(struct l2tp_session
*session
, int version
)
1680 if (version
== L2TP_HDR_VER_2
) {
1681 session
->hdr_len
= 6;
1682 if (session
->send_seq
)
1683 session
->hdr_len
+= 4;
1685 session
->hdr_len
= 4 + session
->cookie_len
+ session
->l2specific_len
+ session
->offset
;
1686 if (session
->tunnel
->encap
== L2TP_ENCAPTYPE_UDP
)
1687 session
->hdr_len
+= 4;
1691 EXPORT_SYMBOL_GPL(l2tp_session_set_header_len
);
1693 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
)
1695 struct l2tp_session
*session
;
1697 session
= kzalloc(sizeof(struct l2tp_session
) + priv_size
, GFP_KERNEL
);
1698 if (session
!= NULL
) {
1699 session
->magic
= L2TP_SESSION_MAGIC
;
1700 session
->tunnel
= tunnel
;
1702 session
->session_id
= session_id
;
1703 session
->peer_session_id
= peer_session_id
;
1705 if (tunnel
->version
== L2TP_HDR_VER_2
)
1706 session
->nr_max
= 0xffff;
1708 session
->nr_max
= 0xffffff;
1709 session
->nr_window_size
= session
->nr_max
/ 2;
1710 session
->nr_oos_count_max
= 4;
1712 /* Use NR of first received packet */
1713 session
->reorder_skip
= 1;
1715 sprintf(&session
->name
[0], "sess %u/%u",
1716 tunnel
->tunnel_id
, session
->session_id
);
1718 skb_queue_head_init(&session
->reorder_q
);
1720 INIT_HLIST_NODE(&session
->hlist
);
1721 INIT_HLIST_NODE(&session
->global_hlist
);
1723 /* Inherit debug options from tunnel */
1724 session
->debug
= tunnel
->debug
;
1727 session
->pwtype
= cfg
->pw_type
;
1728 session
->debug
= cfg
->debug
;
1729 session
->mtu
= cfg
->mtu
;
1730 session
->mru
= cfg
->mru
;
1731 session
->send_seq
= cfg
->send_seq
;
1732 session
->recv_seq
= cfg
->recv_seq
;
1733 session
->lns_mode
= cfg
->lns_mode
;
1734 session
->reorder_timeout
= cfg
->reorder_timeout
;
1735 session
->offset
= cfg
->offset
;
1736 session
->l2specific_type
= cfg
->l2specific_type
;
1737 session
->l2specific_len
= cfg
->l2specific_len
;
1738 session
->cookie_len
= cfg
->cookie_len
;
1739 memcpy(&session
->cookie
[0], &cfg
->cookie
[0], cfg
->cookie_len
);
1740 session
->peer_cookie_len
= cfg
->peer_cookie_len
;
1741 memcpy(&session
->peer_cookie
[0], &cfg
->peer_cookie
[0], cfg
->peer_cookie_len
);
1744 if (tunnel
->version
== L2TP_HDR_VER_2
)
1745 session
->build_header
= l2tp_build_l2tpv2_header
;
1747 session
->build_header
= l2tp_build_l2tpv3_header
;
1749 l2tp_session_set_header_len(session
, tunnel
->version
);
1751 refcount_set(&session
->ref_count
, 1);
1756 return ERR_PTR(-ENOMEM
);
1758 EXPORT_SYMBOL_GPL(l2tp_session_create
);
1760 /*****************************************************************************
1762 *****************************************************************************/
1764 static __net_init
int l2tp_init_net(struct net
*net
)
1766 struct l2tp_net
*pn
= net_generic(net
, l2tp_net_id
);
1769 INIT_LIST_HEAD(&pn
->l2tp_tunnel_list
);
1770 spin_lock_init(&pn
->l2tp_tunnel_list_lock
);
1772 for (hash
= 0; hash
< L2TP_HASH_SIZE_2
; hash
++)
1773 INIT_HLIST_HEAD(&pn
->l2tp_session_hlist
[hash
]);
1775 spin_lock_init(&pn
->l2tp_session_hlist_lock
);
1780 static __net_exit
void l2tp_exit_net(struct net
*net
)
1782 struct l2tp_net
*pn
= l2tp_pernet(net
);
1783 struct l2tp_tunnel
*tunnel
= NULL
;
1787 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
1788 l2tp_tunnel_delete(tunnel
);
1790 rcu_read_unlock_bh();
1792 flush_workqueue(l2tp_wq
);
1795 for (hash
= 0; hash
< L2TP_HASH_SIZE_2
; hash
++)
1796 WARN_ON_ONCE(!hlist_empty(&pn
->l2tp_session_hlist
[hash
]));
1799 static struct pernet_operations l2tp_net_ops
= {
1800 .init
= l2tp_init_net
,
1801 .exit
= l2tp_exit_net
,
1803 .size
= sizeof(struct l2tp_net
),
1806 static int __init
l2tp_init(void)
1810 rc
= register_pernet_device(&l2tp_net_ops
);
1814 l2tp_wq
= alloc_workqueue("l2tp", WQ_UNBOUND
, 0);
1816 pr_err("alloc_workqueue failed\n");
1817 unregister_pernet_device(&l2tp_net_ops
);
1822 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION
);
1828 static void __exit
l2tp_exit(void)
1830 unregister_pernet_device(&l2tp_net_ops
);
1832 destroy_workqueue(l2tp_wq
);
1837 module_init(l2tp_init
);
1838 module_exit(l2tp_exit
);
1840 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1841 MODULE_DESCRIPTION("L2TP core");
1842 MODULE_LICENSE("GPL");
1843 MODULE_VERSION(L2TP_DRV_VERSION
);