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_session_set_header_len(struct l2tp_session
*session
, int version
);
116 static void l2tp_tunnel_free(struct l2tp_tunnel
*tunnel
);
118 static inline struct l2tp_net
*l2tp_pernet(struct net
*net
)
122 return net_generic(net
, l2tp_net_id
);
125 /* Tunnel reference counts. Incremented per session that is added to
128 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel
*tunnel
)
130 atomic_inc(&tunnel
->ref_count
);
133 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel
*tunnel
)
135 if (atomic_dec_and_test(&tunnel
->ref_count
))
136 l2tp_tunnel_free(tunnel
);
138 #ifdef L2TP_REFCNT_DEBUG
139 #define l2tp_tunnel_inc_refcount(_t) \
141 pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \
142 __func__, __LINE__, (_t)->name, \
143 atomic_read(&_t->ref_count)); \
144 l2tp_tunnel_inc_refcount_1(_t); \
146 #define l2tp_tunnel_dec_refcount(_t)
148 pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \
149 __func__
, __LINE__
, (_t
)->name
, \
150 atomic_read(&_t
->ref_count
)); \
151 l2tp_tunnel_dec_refcount_1(_t
); \
154 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
155 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
158 /* Session hash global list for L2TPv3.
159 * The session_id SHOULD be random according to RFC3931, but several
160 * L2TP implementations use incrementing session_ids. So we do a real
161 * hash on the session_id, rather than a simple bitmask.
163 static inline struct hlist_head
*
164 l2tp_session_id_hash_2(struct l2tp_net
*pn
, u32 session_id
)
166 return &pn
->l2tp_session_hlist
[hash_32(session_id
, L2TP_HASH_BITS_2
)];
170 /* Lookup the tunnel socket, possibly involving the fs code if the socket is
171 * owned by userspace. A struct sock returned from this function must be
172 * released using l2tp_tunnel_sock_put once you're done with it.
174 struct sock
*l2tp_tunnel_sock_lookup(struct l2tp_tunnel
*tunnel
)
177 struct socket
*sock
= NULL
;
178 struct sock
*sk
= NULL
;
183 if (tunnel
->fd
>= 0) {
184 /* Socket is owned by userspace, who might be in the process
185 * of closing it. Look the socket up using the fd to ensure
188 sock
= sockfd_lookup(tunnel
->fd
, &err
);
192 /* Socket is owned by kernelspace */
200 EXPORT_SYMBOL_GPL(l2tp_tunnel_sock_lookup
);
202 /* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */
203 void l2tp_tunnel_sock_put(struct sock
*sk
)
205 struct l2tp_tunnel
*tunnel
= l2tp_sock_to_tunnel(sk
);
207 if (tunnel
->fd
>= 0) {
208 /* Socket is owned by userspace */
209 sockfd_put(sk
->sk_socket
);
215 EXPORT_SYMBOL_GPL(l2tp_tunnel_sock_put
);
217 /* Lookup a session by id in the global session list
219 static struct l2tp_session
*l2tp_session_find_2(struct net
*net
, u32 session_id
)
221 struct l2tp_net
*pn
= l2tp_pernet(net
);
222 struct hlist_head
*session_list
=
223 l2tp_session_id_hash_2(pn
, session_id
);
224 struct l2tp_session
*session
;
227 hlist_for_each_entry_rcu(session
, session_list
, global_hlist
) {
228 if (session
->session_id
== session_id
) {
229 rcu_read_unlock_bh();
233 rcu_read_unlock_bh();
238 /* Session hash list.
239 * The session_id SHOULD be random according to RFC2661, but several
240 * L2TP implementations (Cisco and Microsoft) use incrementing
241 * session_ids. So we do a real hash on the session_id, rather than a
244 static inline struct hlist_head
*
245 l2tp_session_id_hash(struct l2tp_tunnel
*tunnel
, u32 session_id
)
247 return &tunnel
->session_hlist
[hash_32(session_id
, L2TP_HASH_BITS
)];
250 /* Lookup a session by id
252 struct l2tp_session
*l2tp_session_find(struct net
*net
, struct l2tp_tunnel
*tunnel
, u32 session_id
)
254 struct hlist_head
*session_list
;
255 struct l2tp_session
*session
;
257 /* In L2TPv3, session_ids are unique over all tunnels and we
258 * sometimes need to look them up before we know the
262 return l2tp_session_find_2(net
, session_id
);
264 session_list
= l2tp_session_id_hash(tunnel
, session_id
);
265 read_lock_bh(&tunnel
->hlist_lock
);
266 hlist_for_each_entry(session
, session_list
, hlist
) {
267 if (session
->session_id
== session_id
) {
268 read_unlock_bh(&tunnel
->hlist_lock
);
272 read_unlock_bh(&tunnel
->hlist_lock
);
276 EXPORT_SYMBOL_GPL(l2tp_session_find
);
278 struct l2tp_session
*l2tp_session_find_nth(struct l2tp_tunnel
*tunnel
, int nth
)
281 struct l2tp_session
*session
;
284 read_lock_bh(&tunnel
->hlist_lock
);
285 for (hash
= 0; hash
< L2TP_HASH_SIZE
; hash
++) {
286 hlist_for_each_entry(session
, &tunnel
->session_hlist
[hash
], hlist
) {
288 read_unlock_bh(&tunnel
->hlist_lock
);
294 read_unlock_bh(&tunnel
->hlist_lock
);
298 EXPORT_SYMBOL_GPL(l2tp_session_find_nth
);
300 /* Lookup a session by interface name.
301 * This is very inefficient but is only used by management interfaces.
303 struct l2tp_session
*l2tp_session_find_by_ifname(struct net
*net
, char *ifname
)
305 struct l2tp_net
*pn
= l2tp_pernet(net
);
307 struct l2tp_session
*session
;
310 for (hash
= 0; hash
< L2TP_HASH_SIZE_2
; hash
++) {
311 hlist_for_each_entry_rcu(session
, &pn
->l2tp_session_hlist
[hash
], global_hlist
) {
312 if (!strcmp(session
->ifname
, ifname
)) {
313 rcu_read_unlock_bh();
319 rcu_read_unlock_bh();
323 EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname
);
325 /* Lookup a tunnel by id
327 struct l2tp_tunnel
*l2tp_tunnel_find(struct net
*net
, u32 tunnel_id
)
329 struct l2tp_tunnel
*tunnel
;
330 struct l2tp_net
*pn
= l2tp_pernet(net
);
333 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
334 if (tunnel
->tunnel_id
== tunnel_id
) {
335 rcu_read_unlock_bh();
339 rcu_read_unlock_bh();
343 EXPORT_SYMBOL_GPL(l2tp_tunnel_find
);
345 struct l2tp_tunnel
*l2tp_tunnel_find_nth(struct net
*net
, int nth
)
347 struct l2tp_net
*pn
= l2tp_pernet(net
);
348 struct l2tp_tunnel
*tunnel
;
352 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
354 rcu_read_unlock_bh();
359 rcu_read_unlock_bh();
363 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth
);
365 /*****************************************************************************
366 * Receive data handling
367 *****************************************************************************/
369 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
372 static void l2tp_recv_queue_skb(struct l2tp_session
*session
, struct sk_buff
*skb
)
374 struct sk_buff
*skbp
;
376 u32 ns
= L2TP_SKB_CB(skb
)->ns
;
378 spin_lock_bh(&session
->reorder_q
.lock
);
379 skb_queue_walk_safe(&session
->reorder_q
, skbp
, tmp
) {
380 if (L2TP_SKB_CB(skbp
)->ns
> ns
) {
381 __skb_queue_before(&session
->reorder_q
, skbp
, skb
);
382 l2tp_dbg(session
, L2TP_MSG_SEQ
,
383 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
384 session
->name
, ns
, L2TP_SKB_CB(skbp
)->ns
,
385 skb_queue_len(&session
->reorder_q
));
386 atomic_long_inc(&session
->stats
.rx_oos_packets
);
391 __skb_queue_tail(&session
->reorder_q
, skb
);
394 spin_unlock_bh(&session
->reorder_q
.lock
);
397 /* Dequeue a single skb.
399 static void l2tp_recv_dequeue_skb(struct l2tp_session
*session
, struct sk_buff
*skb
)
401 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
402 int length
= L2TP_SKB_CB(skb
)->length
;
404 /* We're about to requeue the skb, so return resources
405 * to its current owner (a socket receive buffer).
409 atomic_long_inc(&tunnel
->stats
.rx_packets
);
410 atomic_long_add(length
, &tunnel
->stats
.rx_bytes
);
411 atomic_long_inc(&session
->stats
.rx_packets
);
412 atomic_long_add(length
, &session
->stats
.rx_bytes
);
414 if (L2TP_SKB_CB(skb
)->has_seq
) {
417 if (tunnel
->version
== L2TP_HDR_VER_2
)
418 session
->nr
&= 0xffff;
420 session
->nr
&= 0xffffff;
422 l2tp_dbg(session
, L2TP_MSG_SEQ
, "%s: updated nr to %hu\n",
423 session
->name
, session
->nr
);
426 /* call private receive handler */
427 if (session
->recv_skb
!= NULL
)
428 (*session
->recv_skb
)(session
, skb
, L2TP_SKB_CB(skb
)->length
);
433 (*session
->deref
)(session
);
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
);
463 (*session
->deref
)(session
);
467 if (L2TP_SKB_CB(skb
)->has_seq
) {
468 if (session
->reorder_skip
) {
469 l2tp_dbg(session
, L2TP_MSG_SEQ
,
470 "%s: advancing nr to next pkt: %u -> %u",
471 session
->name
, session
->nr
,
472 L2TP_SKB_CB(skb
)->ns
);
473 session
->reorder_skip
= 0;
474 session
->nr
= L2TP_SKB_CB(skb
)->ns
;
476 if (L2TP_SKB_CB(skb
)->ns
!= session
->nr
) {
477 l2tp_dbg(session
, L2TP_MSG_SEQ
,
478 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
479 session
->name
, L2TP_SKB_CB(skb
)->ns
,
480 L2TP_SKB_CB(skb
)->length
, session
->nr
,
481 skb_queue_len(&session
->reorder_q
));
485 __skb_unlink(skb
, &session
->reorder_q
);
487 /* Process the skb. We release the queue lock while we
488 * do so to let other contexts process the queue.
490 spin_unlock_bh(&session
->reorder_q
.lock
);
491 l2tp_recv_dequeue_skb(session
, skb
);
496 spin_unlock_bh(&session
->reorder_q
.lock
);
499 static inline int l2tp_verify_udp_checksum(struct sock
*sk
,
502 struct udphdr
*uh
= udp_hdr(skb
);
503 u16 ulen
= ntohs(uh
->len
);
506 if (sk
->sk_no_check
|| skb_csum_unnecessary(skb
))
509 #if IS_ENABLED(CONFIG_IPV6)
510 if (sk
->sk_family
== PF_INET6
) {
512 LIMIT_NETDEBUG(KERN_INFO
"L2TP: IPv6: checksum is 0\n");
515 if ((skb
->ip_summed
== CHECKSUM_COMPLETE
) &&
516 !csum_ipv6_magic(&ipv6_hdr(skb
)->saddr
,
517 &ipv6_hdr(skb
)->daddr
, ulen
,
518 IPPROTO_UDP
, skb
->csum
)) {
519 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
522 skb
->csum
= ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb
)->saddr
,
523 &ipv6_hdr(skb
)->daddr
,
524 skb
->len
, IPPROTO_UDP
,
529 struct inet_sock
*inet
;
533 psum
= csum_tcpudp_nofold(inet
->inet_saddr
, inet
->inet_daddr
,
534 ulen
, IPPROTO_UDP
, 0);
536 if ((skb
->ip_summed
== CHECKSUM_COMPLETE
) &&
537 !csum_fold(csum_add(psum
, skb
->csum
)))
542 return __skb_checksum_complete(skb
);
545 /* Do receive processing of L2TP data frames. We handle both L2TPv2
546 * and L2TPv3 data frames here.
548 * L2TPv2 Data Message Header
551 * 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
552 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
553 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
554 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
555 * | Tunnel ID | Session ID |
556 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
557 * | Ns (opt) | Nr (opt) |
558 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
559 * | Offset Size (opt) | Offset pad... (opt)
560 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
562 * Data frames are marked by T=0. All other fields are the same as
563 * those in L2TP control frames.
565 * L2TPv3 Data Message Header
567 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
568 * | L2TP Session Header |
569 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
570 * | L2-Specific Sublayer |
571 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
572 * | Tunnel Payload ...
573 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
575 * L2TPv3 Session Header Over IP
578 * 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
579 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
581 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
582 * | Cookie (optional, maximum 64 bits)...
583 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
585 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
587 * L2TPv3 L2-Specific Sublayer Format
590 * 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
591 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
592 * |x|S|x|x|x|x|x|x| Sequence Number |
593 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
595 * Cookie value, sublayer format and offset (pad) are negotiated with
596 * the peer when the session is set up. Unlike L2TPv2, we do not need
597 * to parse the packet header to determine if optional fields are
600 * Caller must already have parsed the frame and determined that it is
601 * a data (not control) frame before coming here. Fields up to the
602 * session-id have already been parsed and ptr points to the data
603 * after the session-id.
605 void l2tp_recv_common(struct l2tp_session
*session
, struct sk_buff
*skb
,
606 unsigned char *ptr
, unsigned char *optr
, u16 hdrflags
,
607 int length
, int (*payload_hook
)(struct sk_buff
*skb
))
609 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
613 /* The ref count is increased since we now hold a pointer to
614 * the session. Take care to decrement the refcnt when exiting
615 * this function from now on...
617 l2tp_session_inc_refcount(session
);
619 (*session
->ref
)(session
);
621 /* Parse and check optional cookie */
622 if (session
->peer_cookie_len
> 0) {
623 if (memcmp(ptr
, &session
->peer_cookie
[0], session
->peer_cookie_len
)) {
624 l2tp_info(tunnel
, L2TP_MSG_DATA
,
625 "%s: cookie mismatch (%u/%u). Discarding.\n",
626 tunnel
->name
, tunnel
->tunnel_id
,
627 session
->session_id
);
628 atomic_long_inc(&session
->stats
.rx_cookie_discards
);
631 ptr
+= session
->peer_cookie_len
;
634 /* Handle the optional sequence numbers. Sequence numbers are
635 * in different places for L2TPv2 and L2TPv3.
637 * If we are the LAC, enable/disable sequence numbers under
638 * the control of the LNS. If no sequence numbers present but
639 * we were expecting them, discard frame.
642 L2TP_SKB_CB(skb
)->has_seq
= 0;
643 if (tunnel
->version
== L2TP_HDR_VER_2
) {
644 if (hdrflags
& L2TP_HDRFLAG_S
) {
645 ns
= ntohs(*(__be16
*) ptr
);
647 nr
= ntohs(*(__be16
*) ptr
);
650 /* Store L2TP info in the skb */
651 L2TP_SKB_CB(skb
)->ns
= ns
;
652 L2TP_SKB_CB(skb
)->has_seq
= 1;
654 l2tp_dbg(session
, L2TP_MSG_SEQ
,
655 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
656 session
->name
, ns
, nr
, session
->nr
);
658 } else if (session
->l2specific_type
== L2TP_L2SPECTYPE_DEFAULT
) {
659 u32 l2h
= ntohl(*(__be32
*) ptr
);
661 if (l2h
& 0x40000000) {
662 ns
= l2h
& 0x00ffffff;
664 /* Store L2TP info in the skb */
665 L2TP_SKB_CB(skb
)->ns
= ns
;
666 L2TP_SKB_CB(skb
)->has_seq
= 1;
668 l2tp_dbg(session
, L2TP_MSG_SEQ
,
669 "%s: recv data ns=%u, session nr=%u\n",
670 session
->name
, ns
, session
->nr
);
674 /* Advance past L2-specific header, if present */
675 ptr
+= session
->l2specific_len
;
677 if (L2TP_SKB_CB(skb
)->has_seq
) {
678 /* Received a packet with sequence numbers. If we're the LNS,
679 * check if we sre sending sequence numbers and if not,
682 if ((!session
->lns_mode
) && (!session
->send_seq
)) {
683 l2tp_info(session
, L2TP_MSG_SEQ
,
684 "%s: requested to enable seq numbers by LNS\n",
686 session
->send_seq
= -1;
687 l2tp_session_set_header_len(session
, tunnel
->version
);
690 /* No sequence numbers.
691 * If user has configured mandatory sequence numbers, discard.
693 if (session
->recv_seq
) {
694 l2tp_warn(session
, L2TP_MSG_SEQ
,
695 "%s: recv data has no seq numbers when required. Discarding.\n",
697 atomic_long_inc(&session
->stats
.rx_seq_discards
);
701 /* If we're the LAC and we're sending sequence numbers, the
702 * LNS has requested that we no longer send sequence numbers.
703 * If we're the LNS and we're sending sequence numbers, the
704 * LAC is broken. Discard the frame.
706 if ((!session
->lns_mode
) && (session
->send_seq
)) {
707 l2tp_info(session
, L2TP_MSG_SEQ
,
708 "%s: requested to disable seq numbers by LNS\n",
710 session
->send_seq
= 0;
711 l2tp_session_set_header_len(session
, tunnel
->version
);
712 } else if (session
->send_seq
) {
713 l2tp_warn(session
, L2TP_MSG_SEQ
,
714 "%s: recv data has no seq numbers when required. Discarding.\n",
716 atomic_long_inc(&session
->stats
.rx_seq_discards
);
721 /* Session data offset is handled differently for L2TPv2 and
722 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
723 * the header. For L2TPv3, the offset is negotiated using AVPs
724 * in the session setup control protocol.
726 if (tunnel
->version
== L2TP_HDR_VER_2
) {
727 /* If offset bit set, skip it. */
728 if (hdrflags
& L2TP_HDRFLAG_O
) {
729 offset
= ntohs(*(__be16
*)ptr
);
733 ptr
+= session
->offset
;
736 if (!pskb_may_pull(skb
, offset
))
739 __skb_pull(skb
, offset
);
741 /* If caller wants to process the payload before we queue the
745 if ((*payload_hook
)(skb
))
748 /* Prepare skb for adding to the session's reorder_q. Hold
749 * packets for max reorder_timeout or 1 second if not
752 L2TP_SKB_CB(skb
)->length
= length
;
753 L2TP_SKB_CB(skb
)->expires
= jiffies
+
754 (session
->reorder_timeout
? session
->reorder_timeout
: HZ
);
756 /* Add packet to the session's receive queue. Reordering is done here, if
757 * enabled. Saved L2TP protocol info is stored in skb->sb[].
759 if (L2TP_SKB_CB(skb
)->has_seq
) {
760 if (session
->reorder_timeout
!= 0) {
761 /* Packet reordering enabled. Add skb to session's
762 * reorder queue, in order of ns.
764 l2tp_recv_queue_skb(session
, skb
);
766 /* Packet reordering disabled. Discard out-of-sequence
769 if (L2TP_SKB_CB(skb
)->ns
!= session
->nr
) {
770 atomic_long_inc(&session
->stats
.rx_seq_discards
);
771 l2tp_dbg(session
, L2TP_MSG_SEQ
,
772 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
773 session
->name
, L2TP_SKB_CB(skb
)->ns
,
774 L2TP_SKB_CB(skb
)->length
, session
->nr
,
775 skb_queue_len(&session
->reorder_q
));
778 skb_queue_tail(&session
->reorder_q
, skb
);
781 /* No sequence numbers. Add the skb to the tail of the
782 * reorder queue. This ensures that it will be
783 * delivered after all previous sequenced skbs.
785 skb_queue_tail(&session
->reorder_q
, skb
);
788 /* Try to dequeue as many skbs from reorder_q as we can. */
789 l2tp_recv_dequeue(session
);
791 l2tp_session_dec_refcount(session
);
796 atomic_long_inc(&session
->stats
.rx_errors
);
800 (*session
->deref
)(session
);
802 l2tp_session_dec_refcount(session
);
804 EXPORT_SYMBOL(l2tp_recv_common
);
806 /* Drop skbs from the session's reorder_q
808 int l2tp_session_queue_purge(struct l2tp_session
*session
)
810 struct sk_buff
*skb
= NULL
;
812 BUG_ON(session
->magic
!= L2TP_SESSION_MAGIC
);
813 while ((skb
= skb_dequeue(&session
->reorder_q
))) {
814 atomic_long_inc(&session
->stats
.rx_errors
);
817 (*session
->deref
)(session
);
821 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge
);
823 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
824 * here. The skb is not on a list when we get here.
825 * Returns 0 if the packet was a data packet and was successfully passed on.
826 * Returns 1 if the packet was not a good data packet and could not be
827 * forwarded. All such packets are passed up to userspace to deal with.
829 static int l2tp_udp_recv_core(struct l2tp_tunnel
*tunnel
, struct sk_buff
*skb
,
830 int (*payload_hook
)(struct sk_buff
*skb
))
832 struct l2tp_session
*session
= NULL
;
833 unsigned char *ptr
, *optr
;
835 u32 tunnel_id
, session_id
;
839 if (tunnel
->sock
&& l2tp_verify_udp_checksum(tunnel
->sock
, skb
))
840 goto discard_bad_csum
;
842 /* UDP always verifies the packet length. */
843 __skb_pull(skb
, sizeof(struct udphdr
));
846 if (!pskb_may_pull(skb
, L2TP_HDR_SIZE_SEQ
)) {
847 l2tp_info(tunnel
, L2TP_MSG_DATA
,
848 "%s: recv short packet (len=%d)\n",
849 tunnel
->name
, skb
->len
);
853 /* Trace packet contents, if enabled */
854 if (tunnel
->debug
& L2TP_MSG_DATA
) {
855 length
= min(32u, skb
->len
);
856 if (!pskb_may_pull(skb
, length
))
859 pr_debug("%s: recv\n", tunnel
->name
);
860 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET
, skb
->data
, length
);
863 /* Point to L2TP header */
864 optr
= ptr
= skb
->data
;
866 /* Get L2TP header flags */
867 hdrflags
= ntohs(*(__be16
*) ptr
);
869 /* Check protocol version */
870 version
= hdrflags
& L2TP_HDR_VER_MASK
;
871 if (version
!= tunnel
->version
) {
872 l2tp_info(tunnel
, L2TP_MSG_DATA
,
873 "%s: recv protocol version mismatch: got %d expected %d\n",
874 tunnel
->name
, version
, tunnel
->version
);
878 /* Get length of L2TP packet */
881 /* If type is control packet, it is handled by userspace. */
882 if (hdrflags
& L2TP_HDRFLAG_T
) {
883 l2tp_dbg(tunnel
, L2TP_MSG_DATA
,
884 "%s: recv control packet, len=%d\n",
885 tunnel
->name
, length
);
892 if (tunnel
->version
== L2TP_HDR_VER_2
) {
893 /* If length is present, skip it */
894 if (hdrflags
& L2TP_HDRFLAG_L
)
897 /* Extract tunnel and session ID */
898 tunnel_id
= ntohs(*(__be16
*) ptr
);
900 session_id
= ntohs(*(__be16
*) ptr
);
903 ptr
+= 2; /* skip reserved bits */
904 tunnel_id
= tunnel
->tunnel_id
;
905 session_id
= ntohl(*(__be32
*) ptr
);
909 /* Find the session context */
910 session
= l2tp_session_find(tunnel
->l2tp_net
, tunnel
, session_id
);
911 if (!session
|| !session
->recv_skb
) {
912 /* Not found? Pass to userspace to deal with */
913 l2tp_info(tunnel
, L2TP_MSG_DATA
,
914 "%s: no session found (%u/%u). Passing up.\n",
915 tunnel
->name
, tunnel_id
, session_id
);
919 l2tp_recv_common(session
, skb
, ptr
, optr
, hdrflags
, length
, payload_hook
);
924 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel
->name
);
925 UDP_INC_STATS_USER(tunnel
->l2tp_net
, UDP_MIB_INERRORS
, 0);
926 atomic_long_inc(&tunnel
->stats
.rx_errors
);
932 /* Put UDP header back */
933 __skb_push(skb
, sizeof(struct udphdr
));
938 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
942 * >0: skb should be passed up to userspace as UDP.
944 int l2tp_udp_encap_recv(struct sock
*sk
, struct sk_buff
*skb
)
946 struct l2tp_tunnel
*tunnel
;
948 tunnel
= l2tp_sock_to_tunnel(sk
);
952 l2tp_dbg(tunnel
, L2TP_MSG_DATA
, "%s: received %d bytes\n",
953 tunnel
->name
, skb
->len
);
955 if (l2tp_udp_recv_core(tunnel
, skb
, tunnel
->recv_payload_hook
))
966 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv
);
968 /************************************************************************
970 ***********************************************************************/
972 /* Build an L2TP header for the session into the buffer provided.
974 static int l2tp_build_l2tpv2_header(struct l2tp_session
*session
, void *buf
)
976 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
979 u16 flags
= L2TP_HDR_VER_2
;
980 u32 tunnel_id
= tunnel
->peer_tunnel_id
;
981 u32 session_id
= session
->peer_session_id
;
983 if (session
->send_seq
)
984 flags
|= L2TP_HDRFLAG_S
;
986 /* Setup L2TP header. */
987 *bufp
++ = htons(flags
);
988 *bufp
++ = htons(tunnel_id
);
989 *bufp
++ = htons(session_id
);
990 if (session
->send_seq
) {
991 *bufp
++ = htons(session
->ns
);
994 session
->ns
&= 0xffff;
995 l2tp_dbg(session
, L2TP_MSG_SEQ
, "%s: updated ns to %u\n",
996 session
->name
, session
->ns
);
1002 static int l2tp_build_l2tpv3_header(struct l2tp_session
*session
, void *buf
)
1004 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1008 /* Setup L2TP header. The header differs slightly for UDP and
1009 * IP encapsulations. For UDP, there is 4 bytes of flags.
1011 if (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) {
1012 u16 flags
= L2TP_HDR_VER_3
;
1013 *((__be16
*) bufp
) = htons(flags
);
1015 *((__be16
*) bufp
) = 0;
1019 *((__be32
*) bufp
) = htonl(session
->peer_session_id
);
1021 if (session
->cookie_len
) {
1022 memcpy(bufp
, &session
->cookie
[0], session
->cookie_len
);
1023 bufp
+= session
->cookie_len
;
1025 if (session
->l2specific_len
) {
1026 if (session
->l2specific_type
== L2TP_L2SPECTYPE_DEFAULT
) {
1028 if (session
->send_seq
) {
1029 l2h
= 0x40000000 | session
->ns
;
1031 session
->ns
&= 0xffffff;
1032 l2tp_dbg(session
, L2TP_MSG_SEQ
,
1033 "%s: updated ns to %u\n",
1034 session
->name
, session
->ns
);
1037 *((__be32
*) bufp
) = htonl(l2h
);
1039 bufp
+= session
->l2specific_len
;
1041 if (session
->offset
)
1042 bufp
+= session
->offset
;
1047 static int l2tp_xmit_core(struct l2tp_session
*session
, struct sk_buff
*skb
,
1048 struct flowi
*fl
, size_t data_len
)
1050 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1051 unsigned int len
= skb
->len
;
1055 if (session
->send_seq
)
1056 l2tp_dbg(session
, L2TP_MSG_DATA
, "%s: send %Zd bytes, ns=%u\n",
1057 session
->name
, data_len
, session
->ns
- 1);
1059 l2tp_dbg(session
, L2TP_MSG_DATA
, "%s: send %Zd bytes\n",
1060 session
->name
, data_len
);
1062 if (session
->debug
& L2TP_MSG_DATA
) {
1063 int uhlen
= (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) ? sizeof(struct udphdr
) : 0;
1064 unsigned char *datap
= skb
->data
+ uhlen
;
1066 pr_debug("%s: xmit\n", session
->name
);
1067 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET
,
1068 datap
, min_t(size_t, 32, len
- uhlen
));
1071 /* Queue the packet to IP for output */
1073 #if IS_ENABLED(CONFIG_IPV6)
1074 if (skb
->sk
->sk_family
== PF_INET6
)
1075 error
= inet6_csk_xmit(skb
, NULL
);
1078 error
= ip_queue_xmit(skb
, fl
);
1082 atomic_long_inc(&tunnel
->stats
.tx_packets
);
1083 atomic_long_add(len
, &tunnel
->stats
.tx_bytes
);
1084 atomic_long_inc(&session
->stats
.tx_packets
);
1085 atomic_long_add(len
, &session
->stats
.tx_bytes
);
1087 atomic_long_inc(&tunnel
->stats
.tx_errors
);
1088 atomic_long_inc(&session
->stats
.tx_errors
);
1094 /* Automatically called when the skb is freed.
1096 static void l2tp_sock_wfree(struct sk_buff
*skb
)
1101 /* For data skbs that we transmit, we associate with the tunnel socket
1102 * but don't do accounting.
1104 static inline void l2tp_skb_set_owner_w(struct sk_buff
*skb
, struct sock
*sk
)
1108 skb
->destructor
= l2tp_sock_wfree
;
1111 #if IS_ENABLED(CONFIG_IPV6)
1112 static void l2tp_xmit_ipv6_csum(struct sock
*sk
, struct sk_buff
*skb
,
1115 struct ipv6_pinfo
*np
= inet6_sk(sk
);
1116 struct udphdr
*uh
= udp_hdr(skb
);
1118 if (!skb_dst(skb
) || !skb_dst(skb
)->dev
||
1119 !(skb_dst(skb
)->dev
->features
& NETIF_F_IPV6_CSUM
)) {
1120 __wsum csum
= skb_checksum(skb
, 0, udp_len
, 0);
1121 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
1122 uh
->check
= csum_ipv6_magic(&np
->saddr
, &np
->daddr
, udp_len
,
1125 uh
->check
= CSUM_MANGLED_0
;
1127 skb
->ip_summed
= CHECKSUM_PARTIAL
;
1128 skb
->csum_start
= skb_transport_header(skb
) - skb
->head
;
1129 skb
->csum_offset
= offsetof(struct udphdr
, check
);
1130 uh
->check
= ~csum_ipv6_magic(&np
->saddr
, &np
->daddr
,
1131 udp_len
, IPPROTO_UDP
, 0);
1136 /* If caller requires the skb to have a ppp header, the header must be
1137 * inserted in the skb data before calling this function.
1139 int l2tp_xmit_skb(struct l2tp_session
*session
, struct sk_buff
*skb
, int hdr_len
)
1141 int data_len
= skb
->len
;
1142 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1143 struct sock
*sk
= tunnel
->sock
;
1146 struct inet_sock
*inet
;
1149 int uhlen
= (tunnel
->encap
== L2TP_ENCAPTYPE_UDP
) ? sizeof(struct udphdr
) : 0;
1151 int ret
= NET_XMIT_SUCCESS
;
1153 /* Check that there's enough headroom in the skb to insert IP,
1154 * UDP and L2TP headers. If not enough, expand it to
1155 * make room. Adjust truesize.
1157 headroom
= NET_SKB_PAD
+ sizeof(struct iphdr
) +
1159 if (skb_cow_head(skb
, headroom
)) {
1161 return NET_XMIT_DROP
;
1165 /* Setup L2TP header */
1166 session
->build_header(session
, __skb_push(skb
, hdr_len
));
1168 /* Reset skb netfilter state */
1169 memset(&(IPCB(skb
)->opt
), 0, sizeof(IPCB(skb
)->opt
));
1170 IPCB(skb
)->flags
&= ~(IPSKB_XFRM_TUNNEL_SIZE
| IPSKB_XFRM_TRANSFORMED
|
1175 if (sock_owned_by_user(sk
)) {
1177 ret
= NET_XMIT_DROP
;
1181 /* Get routing info from the tunnel socket */
1183 skb_dst_set(skb
, dst_clone(__sk_dst_check(sk
, 0)));
1186 fl
= &inet
->cork
.fl
;
1187 switch (tunnel
->encap
) {
1188 case L2TP_ENCAPTYPE_UDP
:
1189 /* Setup UDP header */
1190 __skb_push(skb
, sizeof(*uh
));
1191 skb_reset_transport_header(skb
);
1193 uh
->source
= inet
->inet_sport
;
1194 uh
->dest
= inet
->inet_dport
;
1195 udp_len
= uhlen
+ hdr_len
+ data_len
;
1196 uh
->len
= htons(udp_len
);
1199 /* Calculate UDP checksum if configured to do so */
1200 #if IS_ENABLED(CONFIG_IPV6)
1201 if (sk
->sk_family
== PF_INET6
)
1202 l2tp_xmit_ipv6_csum(sk
, skb
, udp_len
);
1205 if (sk
->sk_no_check
== UDP_CSUM_NOXMIT
)
1206 skb
->ip_summed
= CHECKSUM_NONE
;
1207 else if ((skb_dst(skb
) && skb_dst(skb
)->dev
) &&
1208 (!(skb_dst(skb
)->dev
->features
& NETIF_F_V4_CSUM
))) {
1209 skb
->ip_summed
= CHECKSUM_COMPLETE
;
1210 csum
= skb_checksum(skb
, 0, udp_len
, 0);
1211 uh
->check
= csum_tcpudp_magic(inet
->inet_saddr
,
1213 udp_len
, IPPROTO_UDP
, csum
);
1215 uh
->check
= CSUM_MANGLED_0
;
1217 skb
->ip_summed
= CHECKSUM_PARTIAL
;
1218 skb
->csum_start
= skb_transport_header(skb
) - skb
->head
;
1219 skb
->csum_offset
= offsetof(struct udphdr
, check
);
1220 uh
->check
= ~csum_tcpudp_magic(inet
->inet_saddr
,
1222 udp_len
, IPPROTO_UDP
, 0);
1226 case L2TP_ENCAPTYPE_IP
:
1230 l2tp_skb_set_owner_w(skb
, sk
);
1232 l2tp_xmit_core(session
, skb
, fl
, data_len
);
1238 EXPORT_SYMBOL_GPL(l2tp_xmit_skb
);
1240 /*****************************************************************************
1241 * Tinnel and session create/destroy.
1242 *****************************************************************************/
1244 /* Tunnel socket destruct hook.
1245 * The tunnel context is deleted only when all session sockets have been
1248 static void l2tp_tunnel_destruct(struct sock
*sk
)
1250 struct l2tp_tunnel
*tunnel
;
1251 struct l2tp_net
*pn
;
1253 tunnel
= sk
->sk_user_data
;
1257 l2tp_info(tunnel
, L2TP_MSG_CONTROL
, "%s: closing...\n", tunnel
->name
);
1260 /* Disable udp encapsulation */
1261 switch (tunnel
->encap
) {
1262 case L2TP_ENCAPTYPE_UDP
:
1263 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1264 (udp_sk(sk
))->encap_type
= 0;
1265 (udp_sk(sk
))->encap_rcv
= NULL
;
1266 (udp_sk(sk
))->encap_destroy
= NULL
;
1268 case L2TP_ENCAPTYPE_IP
:
1272 /* Remove hooks into tunnel socket */
1273 sk
->sk_destruct
= tunnel
->old_sk_destruct
;
1274 sk
->sk_user_data
= NULL
;
1275 tunnel
->sock
= NULL
;
1277 /* Remove the tunnel struct from the tunnel list */
1278 pn
= l2tp_pernet(tunnel
->l2tp_net
);
1279 spin_lock_bh(&pn
->l2tp_tunnel_list_lock
);
1280 list_del_rcu(&tunnel
->list
);
1281 spin_unlock_bh(&pn
->l2tp_tunnel_list_lock
);
1282 atomic_dec(&l2tp_tunnel_count
);
1284 l2tp_tunnel_closeall(tunnel
);
1285 l2tp_tunnel_dec_refcount(tunnel
);
1287 /* Call the original destructor */
1288 if (sk
->sk_destruct
)
1289 (*sk
->sk_destruct
)(sk
);
1294 /* When the tunnel is closed, all the attached sessions need to go too.
1296 void l2tp_tunnel_closeall(struct l2tp_tunnel
*tunnel
)
1299 struct hlist_node
*walk
;
1300 struct hlist_node
*tmp
;
1301 struct l2tp_session
*session
;
1303 BUG_ON(tunnel
== NULL
);
1305 l2tp_info(tunnel
, L2TP_MSG_CONTROL
, "%s: closing all sessions...\n",
1308 write_lock_bh(&tunnel
->hlist_lock
);
1309 for (hash
= 0; hash
< L2TP_HASH_SIZE
; hash
++) {
1311 hlist_for_each_safe(walk
, tmp
, &tunnel
->session_hlist
[hash
]) {
1312 session
= hlist_entry(walk
, struct l2tp_session
, hlist
);
1314 l2tp_info(session
, L2TP_MSG_CONTROL
,
1315 "%s: closing session\n", session
->name
);
1317 hlist_del_init(&session
->hlist
);
1319 if (session
->ref
!= NULL
)
1320 (*session
->ref
)(session
);
1322 write_unlock_bh(&tunnel
->hlist_lock
);
1324 __l2tp_session_unhash(session
);
1325 l2tp_session_queue_purge(session
);
1327 if (session
->session_close
!= NULL
)
1328 (*session
->session_close
)(session
);
1330 if (session
->deref
!= NULL
)
1331 (*session
->deref
)(session
);
1333 l2tp_session_dec_refcount(session
);
1335 write_lock_bh(&tunnel
->hlist_lock
);
1337 /* Now restart from the beginning of this hash
1338 * chain. We always remove a session from the
1339 * list so we are guaranteed to make forward
1345 write_unlock_bh(&tunnel
->hlist_lock
);
1347 EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall
);
1349 /* Tunnel socket destroy hook for UDP encapsulation */
1350 static void l2tp_udp_encap_destroy(struct sock
*sk
)
1352 struct l2tp_tunnel
*tunnel
= l2tp_sock_to_tunnel(sk
);
1354 l2tp_tunnel_closeall(tunnel
);
1359 /* Really kill the tunnel.
1360 * Come here only when all sessions have been cleared from the tunnel.
1362 static void l2tp_tunnel_free(struct l2tp_tunnel
*tunnel
)
1364 BUG_ON(atomic_read(&tunnel
->ref_count
) != 0);
1365 BUG_ON(tunnel
->sock
!= NULL
);
1366 l2tp_info(tunnel
, L2TP_MSG_CONTROL
, "%s: free...\n", tunnel
->name
);
1367 kfree_rcu(tunnel
, rcu
);
1370 /* Workqueue tunnel deletion function */
1371 static void l2tp_tunnel_del_work(struct work_struct
*work
)
1373 struct l2tp_tunnel
*tunnel
= NULL
;
1374 struct socket
*sock
= NULL
;
1375 struct sock
*sk
= NULL
;
1377 tunnel
= container_of(work
, struct l2tp_tunnel
, del_work
);
1378 sk
= l2tp_tunnel_sock_lookup(tunnel
);
1382 sock
= sk
->sk_socket
;
1384 /* If the tunnel socket was created by userspace, then go through the
1385 * inet layer to shut the socket down, and let userspace close it.
1386 * Otherwise, if we created the socket directly within the kernel, use
1387 * the sk API to release it here.
1388 * In either case the tunnel resources are freed in the socket
1389 * destructor when the tunnel socket goes away.
1391 if (tunnel
->fd
>= 0) {
1393 inet_shutdown(sock
, 2);
1396 kernel_sock_shutdown(sock
, SHUT_RDWR
);
1397 sk_release_kernel(sk
);
1400 l2tp_tunnel_sock_put(sk
);
1403 /* Create a socket for the tunnel, if one isn't set up by
1404 * userspace. This is used for static tunnels where there is no
1405 * managing L2TP daemon.
1407 * Since we don't want these sockets to keep a namespace alive by
1408 * themselves, we drop the socket's namespace refcount after creation.
1409 * These sockets are freed when the namespace exits using the pernet
1412 static int l2tp_tunnel_sock_create(struct net
*net
,
1415 struct l2tp_tunnel_cfg
*cfg
,
1416 struct socket
**sockp
)
1419 struct socket
*sock
= NULL
;
1420 struct sockaddr_in udp_addr
= {0};
1421 struct sockaddr_l2tpip ip_addr
= {0};
1422 #if IS_ENABLED(CONFIG_IPV6)
1423 struct sockaddr_in6 udp6_addr
= {0};
1424 struct sockaddr_l2tpip6 ip6_addr
= {0};
1427 switch (cfg
->encap
) {
1428 case L2TP_ENCAPTYPE_UDP
:
1429 #if IS_ENABLED(CONFIG_IPV6)
1430 if (cfg
->local_ip6
&& cfg
->peer_ip6
) {
1431 err
= sock_create_kern(AF_INET6
, SOCK_DGRAM
, 0, &sock
);
1435 sk_change_net(sock
->sk
, net
);
1437 udp6_addr
.sin6_family
= AF_INET6
;
1438 memcpy(&udp6_addr
.sin6_addr
, cfg
->local_ip6
,
1439 sizeof(udp6_addr
.sin6_addr
));
1440 udp6_addr
.sin6_port
= htons(cfg
->local_udp_port
);
1441 err
= kernel_bind(sock
, (struct sockaddr
*) &udp6_addr
,
1446 udp6_addr
.sin6_family
= AF_INET6
;
1447 memcpy(&udp6_addr
.sin6_addr
, cfg
->peer_ip6
,
1448 sizeof(udp6_addr
.sin6_addr
));
1449 udp6_addr
.sin6_port
= htons(cfg
->peer_udp_port
);
1450 err
= kernel_connect(sock
,
1451 (struct sockaddr
*) &udp6_addr
,
1452 sizeof(udp6_addr
), 0);
1458 err
= sock_create_kern(AF_INET
, SOCK_DGRAM
, 0, &sock
);
1462 sk_change_net(sock
->sk
, net
);
1464 udp_addr
.sin_family
= AF_INET
;
1465 udp_addr
.sin_addr
= cfg
->local_ip
;
1466 udp_addr
.sin_port
= htons(cfg
->local_udp_port
);
1467 err
= kernel_bind(sock
, (struct sockaddr
*) &udp_addr
,
1472 udp_addr
.sin_family
= AF_INET
;
1473 udp_addr
.sin_addr
= cfg
->peer_ip
;
1474 udp_addr
.sin_port
= htons(cfg
->peer_udp_port
);
1475 err
= kernel_connect(sock
,
1476 (struct sockaddr
*) &udp_addr
,
1477 sizeof(udp_addr
), 0);
1482 if (!cfg
->use_udp_checksums
)
1483 sock
->sk
->sk_no_check
= UDP_CSUM_NOXMIT
;
1487 case L2TP_ENCAPTYPE_IP
:
1488 #if IS_ENABLED(CONFIG_IPV6)
1489 if (cfg
->local_ip6
&& cfg
->peer_ip6
) {
1490 err
= sock_create_kern(AF_INET6
, SOCK_DGRAM
,
1491 IPPROTO_L2TP
, &sock
);
1495 sk_change_net(sock
->sk
, net
);
1497 ip6_addr
.l2tp_family
= AF_INET6
;
1498 memcpy(&ip6_addr
.l2tp_addr
, cfg
->local_ip6
,
1499 sizeof(ip6_addr
.l2tp_addr
));
1500 ip6_addr
.l2tp_conn_id
= tunnel_id
;
1501 err
= kernel_bind(sock
, (struct sockaddr
*) &ip6_addr
,
1506 ip6_addr
.l2tp_family
= AF_INET6
;
1507 memcpy(&ip6_addr
.l2tp_addr
, cfg
->peer_ip6
,
1508 sizeof(ip6_addr
.l2tp_addr
));
1509 ip6_addr
.l2tp_conn_id
= peer_tunnel_id
;
1510 err
= kernel_connect(sock
,
1511 (struct sockaddr
*) &ip6_addr
,
1512 sizeof(ip6_addr
), 0);
1518 err
= sock_create_kern(AF_INET
, SOCK_DGRAM
,
1519 IPPROTO_L2TP
, &sock
);
1523 sk_change_net(sock
->sk
, net
);
1525 ip_addr
.l2tp_family
= AF_INET
;
1526 ip_addr
.l2tp_addr
= cfg
->local_ip
;
1527 ip_addr
.l2tp_conn_id
= tunnel_id
;
1528 err
= kernel_bind(sock
, (struct sockaddr
*) &ip_addr
,
1533 ip_addr
.l2tp_family
= AF_INET
;
1534 ip_addr
.l2tp_addr
= cfg
->peer_ip
;
1535 ip_addr
.l2tp_conn_id
= peer_tunnel_id
;
1536 err
= kernel_connect(sock
, (struct sockaddr
*) &ip_addr
,
1537 sizeof(ip_addr
), 0);
1549 if ((err
< 0) && sock
) {
1550 kernel_sock_shutdown(sock
, SHUT_RDWR
);
1551 sk_release_kernel(sock
->sk
);
1558 static struct lock_class_key l2tp_socket_class
;
1560 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
)
1562 struct l2tp_tunnel
*tunnel
= NULL
;
1564 struct socket
*sock
= NULL
;
1565 struct sock
*sk
= NULL
;
1566 struct l2tp_net
*pn
;
1567 enum l2tp_encap_type encap
= L2TP_ENCAPTYPE_UDP
;
1569 /* Get the tunnel socket from the fd, which was opened by
1570 * the userspace L2TP daemon. If not specified, create a
1574 err
= l2tp_tunnel_sock_create(net
, tunnel_id
, peer_tunnel_id
,
1579 sock
= sockfd_lookup(fd
, &err
);
1581 pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n",
1582 tunnel_id
, fd
, err
);
1587 /* Reject namespace mismatches */
1588 if (!net_eq(sock_net(sock
->sk
), net
)) {
1589 pr_err("tunl %u: netns mismatch\n", tunnel_id
);
1600 /* Quick sanity checks */
1602 case L2TP_ENCAPTYPE_UDP
:
1603 err
= -EPROTONOSUPPORT
;
1604 if (sk
->sk_protocol
!= IPPROTO_UDP
) {
1605 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1606 tunnel_id
, fd
, sk
->sk_protocol
, IPPROTO_UDP
);
1610 case L2TP_ENCAPTYPE_IP
:
1611 err
= -EPROTONOSUPPORT
;
1612 if (sk
->sk_protocol
!= IPPROTO_L2TP
) {
1613 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1614 tunnel_id
, fd
, sk
->sk_protocol
, IPPROTO_L2TP
);
1620 /* Check if this socket has already been prepped */
1621 tunnel
= (struct l2tp_tunnel
*)sk
->sk_user_data
;
1622 if (tunnel
!= NULL
) {
1623 /* This socket has already been prepped */
1628 tunnel
= kzalloc(sizeof(struct l2tp_tunnel
), GFP_KERNEL
);
1629 if (tunnel
== NULL
) {
1634 tunnel
->version
= version
;
1635 tunnel
->tunnel_id
= tunnel_id
;
1636 tunnel
->peer_tunnel_id
= peer_tunnel_id
;
1637 tunnel
->debug
= L2TP_DEFAULT_DEBUG_FLAGS
;
1639 tunnel
->magic
= L2TP_TUNNEL_MAGIC
;
1640 sprintf(&tunnel
->name
[0], "tunl %u", tunnel_id
);
1641 rwlock_init(&tunnel
->hlist_lock
);
1643 /* The net we belong to */
1644 tunnel
->l2tp_net
= net
;
1645 pn
= l2tp_pernet(net
);
1648 tunnel
->debug
= cfg
->debug
;
1650 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1651 tunnel
->encap
= encap
;
1652 if (encap
== L2TP_ENCAPTYPE_UDP
) {
1653 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1654 udp_sk(sk
)->encap_type
= UDP_ENCAP_L2TPINUDP
;
1655 udp_sk(sk
)->encap_rcv
= l2tp_udp_encap_recv
;
1656 udp_sk(sk
)->encap_destroy
= l2tp_udp_encap_destroy
;
1657 #if IS_ENABLED(CONFIG_IPV6)
1658 if (sk
->sk_family
== PF_INET6
)
1659 udpv6_encap_enable();
1665 sk
->sk_user_data
= tunnel
;
1667 /* Hook on the tunnel socket destructor so that we can cleanup
1668 * if the tunnel socket goes away.
1670 tunnel
->old_sk_destruct
= sk
->sk_destruct
;
1671 sk
->sk_destruct
= &l2tp_tunnel_destruct
;
1674 lockdep_set_class_and_name(&sk
->sk_lock
.slock
, &l2tp_socket_class
, "l2tp_sock");
1676 sk
->sk_allocation
= GFP_ATOMIC
;
1678 /* Init delete workqueue struct */
1679 INIT_WORK(&tunnel
->del_work
, l2tp_tunnel_del_work
);
1681 /* Add tunnel to our list */
1682 INIT_LIST_HEAD(&tunnel
->list
);
1683 atomic_inc(&l2tp_tunnel_count
);
1685 /* Bump the reference count. The tunnel context is deleted
1686 * only when this drops to zero. Must be done before list insertion
1688 l2tp_tunnel_inc_refcount(tunnel
);
1689 spin_lock_bh(&pn
->l2tp_tunnel_list_lock
);
1690 list_add_rcu(&tunnel
->list
, &pn
->l2tp_tunnel_list
);
1691 spin_unlock_bh(&pn
->l2tp_tunnel_list_lock
);
1698 /* If tunnel's socket was created by the kernel, it doesn't
1701 if (sock
&& sock
->file
)
1706 EXPORT_SYMBOL_GPL(l2tp_tunnel_create
);
1708 /* This function is used by the netlink TUNNEL_DELETE command.
1710 int l2tp_tunnel_delete(struct l2tp_tunnel
*tunnel
)
1712 l2tp_tunnel_closeall(tunnel
);
1713 return (false == queue_work(l2tp_wq
, &tunnel
->del_work
));
1715 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete
);
1717 /* Really kill the session.
1719 void l2tp_session_free(struct l2tp_session
*session
)
1721 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1723 BUG_ON(atomic_read(&session
->ref_count
) != 0);
1726 BUG_ON(tunnel
->magic
!= L2TP_TUNNEL_MAGIC
);
1727 if (session
->session_id
!= 0)
1728 atomic_dec(&l2tp_session_count
);
1729 sock_put(tunnel
->sock
);
1730 session
->tunnel
= NULL
;
1731 l2tp_tunnel_dec_refcount(tunnel
);
1738 EXPORT_SYMBOL_GPL(l2tp_session_free
);
1740 /* Remove an l2tp session from l2tp_core's hash lists.
1741 * Provides a tidyup interface for pseudowire code which can't just route all
1742 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close
1745 void __l2tp_session_unhash(struct l2tp_session
*session
)
1747 struct l2tp_tunnel
*tunnel
= session
->tunnel
;
1749 /* Remove the session from core hashes */
1751 /* Remove from the per-tunnel hash */
1752 write_lock_bh(&tunnel
->hlist_lock
);
1753 hlist_del_init(&session
->hlist
);
1754 write_unlock_bh(&tunnel
->hlist_lock
);
1756 /* For L2TPv3 we have a per-net hash: remove from there, too */
1757 if (tunnel
->version
!= L2TP_HDR_VER_2
) {
1758 struct l2tp_net
*pn
= l2tp_pernet(tunnel
->l2tp_net
);
1759 spin_lock_bh(&pn
->l2tp_session_hlist_lock
);
1760 hlist_del_init_rcu(&session
->global_hlist
);
1761 spin_unlock_bh(&pn
->l2tp_session_hlist_lock
);
1766 EXPORT_SYMBOL_GPL(__l2tp_session_unhash
);
1768 /* This function is used by the netlink SESSION_DELETE command and by
1771 int l2tp_session_delete(struct l2tp_session
*session
)
1774 (*session
->ref
)(session
);
1775 __l2tp_session_unhash(session
);
1776 l2tp_session_queue_purge(session
);
1777 if (session
->session_close
!= NULL
)
1778 (*session
->session_close
)(session
);
1780 (*session
->ref
)(session
);
1781 l2tp_session_dec_refcount(session
);
1784 EXPORT_SYMBOL_GPL(l2tp_session_delete
);
1786 /* We come here whenever a session's send_seq, cookie_len or
1787 * l2specific_len parameters are set.
1789 static void l2tp_session_set_header_len(struct l2tp_session
*session
, int version
)
1791 if (version
== L2TP_HDR_VER_2
) {
1792 session
->hdr_len
= 6;
1793 if (session
->send_seq
)
1794 session
->hdr_len
+= 4;
1796 session
->hdr_len
= 4 + session
->cookie_len
+ session
->l2specific_len
+ session
->offset
;
1797 if (session
->tunnel
->encap
== L2TP_ENCAPTYPE_UDP
)
1798 session
->hdr_len
+= 4;
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
;
1816 sprintf(&session
->name
[0], "sess %u/%u",
1817 tunnel
->tunnel_id
, session
->session_id
);
1819 skb_queue_head_init(&session
->reorder_q
);
1821 INIT_HLIST_NODE(&session
->hlist
);
1822 INIT_HLIST_NODE(&session
->global_hlist
);
1824 /* Inherit debug options from tunnel */
1825 session
->debug
= tunnel
->debug
;
1828 session
->pwtype
= cfg
->pw_type
;
1829 session
->debug
= cfg
->debug
;
1830 session
->mtu
= cfg
->mtu
;
1831 session
->mru
= cfg
->mru
;
1832 session
->send_seq
= cfg
->send_seq
;
1833 session
->recv_seq
= cfg
->recv_seq
;
1834 session
->lns_mode
= cfg
->lns_mode
;
1835 session
->reorder_timeout
= cfg
->reorder_timeout
;
1836 session
->offset
= cfg
->offset
;
1837 session
->l2specific_type
= cfg
->l2specific_type
;
1838 session
->l2specific_len
= cfg
->l2specific_len
;
1839 session
->cookie_len
= cfg
->cookie_len
;
1840 memcpy(&session
->cookie
[0], &cfg
->cookie
[0], cfg
->cookie_len
);
1841 session
->peer_cookie_len
= cfg
->peer_cookie_len
;
1842 memcpy(&session
->peer_cookie
[0], &cfg
->peer_cookie
[0], cfg
->peer_cookie_len
);
1845 if (tunnel
->version
== L2TP_HDR_VER_2
)
1846 session
->build_header
= l2tp_build_l2tpv2_header
;
1848 session
->build_header
= l2tp_build_l2tpv3_header
;
1850 l2tp_session_set_header_len(session
, tunnel
->version
);
1852 /* Bump the reference count. The session context is deleted
1853 * only when this drops to zero.
1855 l2tp_session_inc_refcount(session
);
1856 l2tp_tunnel_inc_refcount(tunnel
);
1858 /* Ensure tunnel socket isn't deleted */
1859 sock_hold(tunnel
->sock
);
1861 /* Add session to the tunnel's hash list */
1862 write_lock_bh(&tunnel
->hlist_lock
);
1863 hlist_add_head(&session
->hlist
,
1864 l2tp_session_id_hash(tunnel
, session_id
));
1865 write_unlock_bh(&tunnel
->hlist_lock
);
1867 /* And to the global session list if L2TPv3 */
1868 if (tunnel
->version
!= L2TP_HDR_VER_2
) {
1869 struct l2tp_net
*pn
= l2tp_pernet(tunnel
->l2tp_net
);
1871 spin_lock_bh(&pn
->l2tp_session_hlist_lock
);
1872 hlist_add_head_rcu(&session
->global_hlist
,
1873 l2tp_session_id_hash_2(pn
, session_id
));
1874 spin_unlock_bh(&pn
->l2tp_session_hlist_lock
);
1877 /* Ignore management session in session count value */
1878 if (session
->session_id
!= 0)
1879 atomic_inc(&l2tp_session_count
);
1884 EXPORT_SYMBOL_GPL(l2tp_session_create
);
1886 /*****************************************************************************
1888 *****************************************************************************/
1890 static __net_init
int l2tp_init_net(struct net
*net
)
1892 struct l2tp_net
*pn
= net_generic(net
, l2tp_net_id
);
1895 INIT_LIST_HEAD(&pn
->l2tp_tunnel_list
);
1896 spin_lock_init(&pn
->l2tp_tunnel_list_lock
);
1898 for (hash
= 0; hash
< L2TP_HASH_SIZE_2
; hash
++)
1899 INIT_HLIST_HEAD(&pn
->l2tp_session_hlist
[hash
]);
1901 spin_lock_init(&pn
->l2tp_session_hlist_lock
);
1906 static __net_exit
void l2tp_exit_net(struct net
*net
)
1908 struct l2tp_net
*pn
= l2tp_pernet(net
);
1909 struct l2tp_tunnel
*tunnel
= NULL
;
1912 list_for_each_entry_rcu(tunnel
, &pn
->l2tp_tunnel_list
, list
) {
1913 (void)l2tp_tunnel_delete(tunnel
);
1915 rcu_read_unlock_bh();
1918 static struct pernet_operations l2tp_net_ops
= {
1919 .init
= l2tp_init_net
,
1920 .exit
= l2tp_exit_net
,
1922 .size
= sizeof(struct l2tp_net
),
1925 static int __init
l2tp_init(void)
1929 rc
= register_pernet_device(&l2tp_net_ops
);
1933 l2tp_wq
= alloc_workqueue("l2tp", WQ_NON_REENTRANT
| WQ_UNBOUND
, 0);
1935 pr_err("alloc_workqueue failed\n");
1940 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION
);
1946 static void __exit
l2tp_exit(void)
1948 unregister_pernet_device(&l2tp_net_ops
);
1950 destroy_workqueue(l2tp_wq
);
1955 module_init(l2tp_init
);
1956 module_exit(l2tp_exit
);
1958 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1959 MODULE_DESCRIPTION("L2TP core");
1960 MODULE_LICENSE("GPL");
1961 MODULE_VERSION(L2TP_DRV_VERSION
);