blob: 91ebf0a3f49975921b9ac4476a400cb6dc68d53a [file] [log] [blame]
Thomas Gleixnerd2912cb2019-06-04 10:11:33 +02001/* SPDX-License-Identifier: GPL-2.0-only */
Tom Parkin20dcb112020-07-22 17:32:06 +01002/* L2TP internal definitions.
James Chapmanfd558d12010-04-02 06:18:33 +00003 *
4 * Copyright (c) 2008,2009 Katalix Systems Ltd
James Chapmanfd558d12010-04-02 06:18:33 +00005 */
Reshetova, Elenafbea9e02017-07-04 15:52:57 +03006#include <linux/refcount.h>
James Chapmanfd558d12010-04-02 06:18:33 +00007
8#ifndef _L2TP_CORE_H_
9#define _L2TP_CORE_H_
10
Guillaume Nault1f5cd2a2018-08-03 12:38:34 +020011#include <net/dst.h>
12#include <net/sock.h>
13
Guillaume Naultd6a61ec2018-08-10 13:21:55 +020014#ifdef CONFIG_XFRM
15#include <net/xfrm.h>
16#endif
17
Tom Parkin340bb1ac2020-07-28 18:20:33 +010018/* Random numbers used for internal consistency checks of tunnel and session structures */
James Chapmanfd558d12010-04-02 06:18:33 +000019#define L2TP_TUNNEL_MAGIC 0x42114DDA
20#define L2TP_SESSION_MAGIC 0x0C04EB7D
21
Tom Parkin340bb1ac2020-07-28 18:20:33 +010022/* Per tunnel session hash table size */
James Chapmanfd558d12010-04-02 06:18:33 +000023#define L2TP_HASH_BITS 4
Tom Parkindbf82f3f2020-07-22 17:32:11 +010024#define L2TP_HASH_SIZE BIT(L2TP_HASH_BITS)
James Chapmanfd558d12010-04-02 06:18:33 +000025
Tom Parkin340bb1ac2020-07-28 18:20:33 +010026/* System-wide session hash table size */
James Chapmanf7faffa2010-04-02 06:18:49 +000027#define L2TP_HASH_BITS_2 8
Tom Parkindbf82f3f2020-07-22 17:32:11 +010028#define L2TP_HASH_SIZE_2 BIT(L2TP_HASH_BITS_2)
James Chapmanf7faffa2010-04-02 06:18:49 +000029
James Chapmanfd558d12010-04-02 06:18:33 +000030struct sk_buff;
31
32struct l2tp_stats {
Tom Parkin7b7c0712013-03-19 06:11:22 +000033 atomic_long_t tx_packets;
34 atomic_long_t tx_bytes;
35 atomic_long_t tx_errors;
36 atomic_long_t rx_packets;
37 atomic_long_t rx_bytes;
38 atomic_long_t rx_seq_discards;
39 atomic_long_t rx_oos_packets;
40 atomic_long_t rx_errors;
41 atomic_long_t rx_cookie_discards;
Matthias Schiffer3e59e882021-03-03 16:50:49 +010042 atomic_long_t rx_invalid;
James Chapmanfd558d12010-04-02 06:18:33 +000043};
44
45struct l2tp_tunnel;
46
Tom Parkin340bb1ac2020-07-28 18:20:33 +010047/* L2TP session configuration */
James Chapmanfd558d12010-04-02 06:18:33 +000048struct l2tp_session_cfg {
James Chapmanf7faffa2010-04-02 06:18:49 +000049 enum l2tp_pwtype pw_type;
Tom Parkin20dcb112020-07-22 17:32:06 +010050 unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */
51 unsigned int send_seq:1; /* send packets with sequence numbers? */
52 unsigned int lns_mode:1; /* behave as LNS?
53 * LAC enables sequence numbers under LNS control.
54 */
James Chapmanf7faffa2010-04-02 06:18:49 +000055 u16 l2specific_type; /* Layer 2 specific type */
56 u8 cookie[8]; /* optional cookie */
57 int cookie_len; /* 0, 4 or 8 bytes */
58 u8 peer_cookie[8]; /* peer's cookie */
59 int peer_cookie_len; /* 0, 4 or 8 bytes */
Tom Parkin20dcb112020-07-22 17:32:06 +010060 int reorder_timeout; /* configured reorder timeout (in jiffies) */
James Chapman309795f2010-04-02 06:19:10 +000061 char *ifname;
James Chapmanfd558d12010-04-02 06:18:33 +000062};
63
Tom Parkin340bb1ac2020-07-28 18:20:33 +010064/* Represents a session (pseudowire) instance.
65 * Tracks runtime state including cookies, dataplane packet sequencing, and IO statistics.
66 * Is linked into a per-tunnel session hashlist; and in the case of an L2TPv3 session into
67 * an additional per-net ("global") hashlist.
68 */
Tom Parkin2a03dd82020-08-22 15:59:05 +010069#define L2TP_SESSION_NAME_MAX 32
James Chapmanfd558d12010-04-02 06:18:33 +000070struct l2tp_session {
Tom Parkin20dcb112020-07-22 17:32:06 +010071 int magic; /* should be L2TP_SESSION_MAGIC */
Guillaume Naultb228a942017-09-22 15:39:24 +020072 long dead;
James Chapmanfd558d12010-04-02 06:18:33 +000073
Tom Parkin20dcb112020-07-22 17:32:06 +010074 struct l2tp_tunnel *tunnel; /* back pointer to tunnel context */
James Chapmanfd558d12010-04-02 06:18:33 +000075 u32 session_id;
76 u32 peer_session_id;
James Chapmanf7faffa2010-04-02 06:18:49 +000077 u8 cookie[8];
78 int cookie_len;
79 u8 peer_cookie[8];
80 int peer_cookie_len;
James Chapmanf7faffa2010-04-02 06:18:49 +000081 u16 l2specific_type;
82 u16 hdr_len;
83 u32 nr; /* session NR state (receive) */
84 u32 ns; /* session NR state (send) */
James Chapmanfd558d12010-04-02 06:18:33 +000085 struct sk_buff_head reorder_q; /* receive reorder queue */
James Chapman8a1631d2013-07-02 20:28:59 +010086 u32 nr_max; /* max NR. Depends on tunnel */
87 u32 nr_window_size; /* NR window size */
James Chapmana0dbd822013-07-02 20:29:00 +010088 u32 nr_oos; /* NR of last OOS packet */
Tom Parkin20dcb112020-07-22 17:32:06 +010089 int nr_oos_count; /* for OOS recovery */
James Chapmana0dbd822013-07-02 20:29:00 +010090 int nr_oos_count_max;
Tom Parkin20dcb112020-07-22 17:32:06 +010091 struct hlist_node hlist; /* hash list node */
Reshetova, Elenaf00c8542017-07-04 15:52:58 +030092 refcount_t ref_count;
James Chapmanfd558d12010-04-02 06:18:33 +000093
Tom Parkin2a03dd82020-08-22 15:59:05 +010094 char name[L2TP_SESSION_NAME_MAX]; /* for logging */
James Chapman309795f2010-04-02 06:19:10 +000095 char ifname[IFNAMSIZ];
Tom Parkin20dcb112020-07-22 17:32:06 +010096 unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */
97 unsigned int send_seq:1; /* send packets with sequence numbers? */
98 unsigned int lns_mode:1; /* behave as LNS?
99 * LAC enables sequence numbers under LNS control.
100 */
Tom Parkin20dcb112020-07-22 17:32:06 +0100101 int reorder_timeout; /* configured reorder timeout (in jiffies) */
James Chapman38d40b32012-05-09 23:43:08 +0000102 int reorder_skip; /* set if skip to next nr */
James Chapmanf7faffa2010-04-02 06:18:49 +0000103 enum l2tp_pwtype pwtype;
James Chapmanfd558d12010-04-02 06:18:33 +0000104 struct l2tp_stats stats;
Tom Parkin20dcb112020-07-22 17:32:06 +0100105 struct hlist_node global_hlist; /* global hash list node */
James Chapmanfd558d12010-04-02 06:18:33 +0000106
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100107 /* Session receive handler for data packets.
108 * Each pseudowire implementation should implement this callback in order to
109 * handle incoming packets. Packets are passed to the pseudowire handler after
110 * reordering, if data sequence numbers are enabled for the session.
111 */
James Chapmanfd558d12010-04-02 06:18:33 +0000112 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100113
114 /* Session close handler.
115 * Each pseudowire implementation may implement this callback in order to carry
116 * out pseudowire-specific shutdown actions.
117 * The callback is called by core after unhashing the session and purging its
118 * reorder queue.
119 */
James Chapmanfd558d12010-04-02 06:18:33 +0000120 void (*session_close)(struct l2tp_session *session);
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100121
122 /* Session show handler.
123 * Pseudowire-specific implementation of debugfs session rendering.
124 * The callback is called by l2tp_debugfs.c after rendering core session
125 * information.
126 */
James Chapman0ad66142010-04-02 06:19:33 +0000127 void (*show)(struct seq_file *m, void *priv);
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100128
Tom Parkin20dcb112020-07-22 17:32:06 +0100129 u8 priv[]; /* private data */
James Chapmanfd558d12010-04-02 06:18:33 +0000130};
131
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100132/* L2TP tunnel configuration */
James Chapmanfd558d12010-04-02 06:18:33 +0000133struct l2tp_tunnel_cfg {
James Chapman0d767512010-04-02 06:19:00 +0000134 enum l2tp_encap_type encap;
James Chapman789a4a22010-04-02 06:19:40 +0000135
136 /* Used only for kernel-created sockets */
137 struct in_addr local_ip;
138 struct in_addr peer_ip;
Chris Elstonf9bac8d2012-04-29 21:48:52 +0000139#if IS_ENABLED(CONFIG_IPV6)
140 struct in6_addr *local_ip6;
141 struct in6_addr *peer_ip6;
142#endif
James Chapman789a4a22010-04-02 06:19:40 +0000143 u16 local_udp_port;
144 u16 peer_udp_port;
Tom Herbert6b649fea2014-05-23 08:47:40 -0700145 unsigned int use_udp_checksums:1,
146 udp6_zero_tx_checksums:1,
147 udp6_zero_rx_checksums:1;
James Chapmanfd558d12010-04-02 06:18:33 +0000148};
149
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100150/* Represents a tunnel instance.
151 * Tracks runtime state including IO statistics.
152 * Holds the tunnel socket (either passed from userspace or directly created by the kernel).
153 * Maintains a hashlist of sessions belonging to the tunnel instance.
154 * Is linked into a per-net list of tunnels.
155 */
Tom Parkin2a03dd82020-08-22 15:59:05 +0100156#define L2TP_TUNNEL_NAME_MAX 20
James Chapmanfd558d12010-04-02 06:18:33 +0000157struct l2tp_tunnel {
158 int magic; /* Should be L2TP_TUNNEL_MAGIC */
Sabrina Dubroca62b982e2017-09-26 16:16:43 +0200159
160 unsigned long dead;
161
xeb@mail.ru99469c32012-08-24 01:07:38 +0000162 struct rcu_head rcu;
Tom Parkin07b8ca32021-11-26 16:09:03 +0000163 spinlock_t hlist_lock; /* write-protection for session_hlist */
Tom Parkin20dcb112020-07-22 17:32:06 +0100164 bool acpt_newsess; /* indicates whether this tunnel accepts
165 * new sessions. Protected by hlist_lock.
Guillaume Naultf3c66d42017-09-01 17:58:48 +0200166 */
James Chapmanfd558d12010-04-02 06:18:33 +0000167 struct hlist_head session_hlist[L2TP_HASH_SIZE];
Tom Parkin20dcb112020-07-22 17:32:06 +0100168 /* hashed list of sessions, hashed by id */
James Chapmanfd558d12010-04-02 06:18:33 +0000169 u32 tunnel_id;
170 u32 peer_tunnel_id;
171 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
172
Tom Parkin2a03dd82020-08-22 15:59:05 +0100173 char name[L2TP_TUNNEL_NAME_MAX]; /* for logging */
James Chapman0d767512010-04-02 06:19:00 +0000174 enum l2tp_encap_type encap;
James Chapmanfd558d12010-04-02 06:18:33 +0000175 struct l2tp_stats stats;
176
Tom Parkin20dcb112020-07-22 17:32:06 +0100177 struct list_head list; /* list node on per-namespace list of tunnels */
James Chapmanfd558d12010-04-02 06:18:33 +0000178 struct net *l2tp_net; /* the net we belong to */
179
Reshetova, Elenafbea9e02017-07-04 15:52:57 +0300180 refcount_t ref_count;
Tom Parkinbef04d12020-07-22 17:32:10 +0100181 void (*old_sk_destruct)(struct sock *sk);
Tom Parkin20dcb112020-07-22 17:32:06 +0100182 struct sock *sock; /* parent socket */
183 int fd; /* parent fd, if tunnel socket was created
184 * by userspace
185 */
James Chapmanfd558d12010-04-02 06:18:33 +0000186
Tom Parkinf8ccac02013-01-31 23:43:00 +0000187 struct work_struct del_work;
James Chapmanfd558d12010-04-02 06:18:33 +0000188};
189
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100190/* Pseudowire ops callbacks for use with the l2tp genetlink interface */
James Chapman309795f2010-04-02 06:19:10 +0000191struct l2tp_nl_cmd_ops {
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100192 /* The pseudowire session create callback is responsible for creating a session
193 * instance for a specific pseudowire type.
194 * It must call l2tp_session_create and l2tp_session_register to register the
195 * session instance, as well as carry out any pseudowire-specific initialisation.
196 * It must return >= 0 on success, or an appropriate negative errno value on failure.
197 */
Guillaume Naultf026bc22017-09-01 17:58:51 +0200198 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
199 u32 session_id, u32 peer_session_id,
200 struct l2tp_session_cfg *cfg);
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100201
202 /* The pseudowire session delete callback is responsible for initiating the deletion
203 * of a session instance.
204 * It must call l2tp_session_delete, as well as carry out any pseudowire-specific
205 * teardown actions.
206 */
Tom Parkin628703f2020-07-28 18:20:30 +0100207 void (*session_delete)(struct l2tp_session *session);
James Chapman309795f2010-04-02 06:19:10 +0000208};
209
James Chapmanfd558d12010-04-02 06:18:33 +0000210static inline void *l2tp_session_priv(struct l2tp_session *session)
211{
212 return &session->priv[0];
213}
214
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100215/* Tunnel and session refcounts */
Tom Parkin52016e22020-07-28 18:20:29 +0100216void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel);
217void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel);
218void l2tp_session_inc_refcount(struct l2tp_session *session);
219void l2tp_session_dec_refcount(struct l2tp_session *session);
220
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100221/* Tunnel and session lookup.
222 * These functions take a reference on the instances they return, so
223 * the caller must ensure that the reference is dropped appropriately.
224 */
Guillaume Nault54652eb2017-08-25 16:51:40 +0200225struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
Guillaume Nault5846c132018-04-12 20:50:33 +0200226struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth);
Guillaume Nault01e28b92018-08-10 13:21:57 +0200227struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel,
228 u32 session_id);
Guillaume Nault5846c132018-04-12 20:50:33 +0200229
Guillaume Nault01e28b92018-08-10 13:21:57 +0200230struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id);
Guillaume Naulta4346212017-10-31 17:36:42 +0100231struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
Guillaume Nault9aaef502017-04-12 10:05:29 +0200232struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
Guillaume Naulta4346212017-10-31 17:36:42 +0100233 const char *ifname);
James Chapmanfd558d12010-04-02 06:18:33 +0000234
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100235/* Tunnel and session lifetime management.
236 * Creation of a new instance is a two-step process: create, then register.
237 * Destruction is triggered using the *_delete functions, and completes asynchronously.
238 */
Tom Parkinc9ccd4c2020-09-03 09:54:49 +0100239int l2tp_tunnel_create(int fd, int version, u32 tunnel_id,
Joe Perchesc1b12032013-10-18 13:48:25 -0700240 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
241 struct l2tp_tunnel **tunnelp);
Guillaume Nault6b9f3422018-04-10 21:01:12 +0200242int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
243 struct l2tp_tunnel_cfg *cfg);
Sabrina Dubroca62b982e2017-09-26 16:16:43 +0200244void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100245
Joe Perchesc1b12032013-10-18 13:48:25 -0700246struct l2tp_session *l2tp_session_create(int priv_size,
247 struct l2tp_tunnel *tunnel,
248 u32 session_id, u32 peer_session_id,
249 struct l2tp_session_cfg *cfg);
Guillaume Nault3953ae72017-10-27 16:51:50 +0200250int l2tp_session_register(struct l2tp_session *session,
251 struct l2tp_tunnel *tunnel);
Tom Parkin628703f2020-07-28 18:20:30 +0100252void l2tp_session_delete(struct l2tp_session *session);
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100253
254/* Receive path helpers. If data sequencing is enabled for the session these
255 * functions handle queuing and reordering prior to passing packets to the
256 * pseudowire code to be passed to userspace.
257 */
Joe Perchesc1b12032013-10-18 13:48:25 -0700258void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
259 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
Guillaume Nault2b139e62018-07-25 14:53:33 +0200260 int length);
Joe Perchesc1b12032013-10-18 13:48:25 -0700261int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
James Chapmanfd558d12010-04-02 06:18:33 +0000262
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100263/* Transmit path helpers for sending packets over the tunnel socket. */
264void l2tp_session_set_header_len(struct l2tp_session *session, int version);
Tom Parkinefe05272020-09-03 09:54:47 +0100265int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb);
James Chapmanfd558d12010-04-02 06:18:33 +0000266
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100267/* Pseudowire management.
268 * Pseudowires should register with l2tp core on module init, and unregister
269 * on module exit.
270 */
271int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
Joe Perchesc1b12032013-10-18 13:48:25 -0700272void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
Tom Parkin340bb1ac2020-07-28 18:20:33 +0100273
274/* IOCTL helper for IP encap modules. */
Breno Leitaoe1d001f2023-06-09 08:27:42 -0700275int l2tp_ioctl(struct sock *sk, int cmd, int *karg);
James Chapman309795f2010-04-02 06:19:10 +0000276
Tom Parkin45faeff2020-09-03 09:54:51 +0100277/* Extract the tunnel structure from a socket's sk_user_data pointer,
278 * validating the tunnel magic feather.
279 */
280struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk);
281
Lorenzo Bianconi62e7b6a2018-01-16 23:01:55 +0100282static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
283{
284 switch (session->l2specific_type) {
285 case L2TP_L2SPECTYPE_DEFAULT:
286 return 4;
287 case L2TP_L2SPECTYPE_NONE:
288 default:
289 return 0;
290 }
291}
292
Guillaume Nault1f5cd2a2018-08-03 12:38:34 +0200293static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel)
294{
295 struct dst_entry *dst;
296 u32 mtu;
297
298 dst = sk_dst_get(tunnel->sock);
299 if (!dst)
300 return 0;
301
302 mtu = dst_mtu(dst);
303 dst_release(dst);
304
305 return mtu;
306}
307
Guillaume Naultd6a61ec2018-08-10 13:21:55 +0200308#ifdef CONFIG_XFRM
309static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
310{
311 struct sock *sk = tunnel->sock;
312
313 return sk && (rcu_access_pointer(sk->sk_policy[0]) ||
314 rcu_access_pointer(sk->sk_policy[1]));
315}
316#else
317static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
318{
319 return false;
320}
321#endif
322
Jacob Wen4522a702019-01-30 14:55:14 +0800323static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb,
324 unsigned char **ptr, unsigned char **optr)
325{
326 int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session);
327
328 if (opt_len > 0) {
329 int off = *ptr - *optr;
330
331 if (!pskb_may_pull(skb, off + opt_len))
332 return -1;
333
334 if (skb->data != *optr) {
335 *optr = skb->data;
336 *ptr = skb->data + off;
337 }
338 }
339
340 return 0;
341}
342
stephen hemmingerf1f39f92015-09-23 21:33:34 -0700343#define MODULE_ALIAS_L2TP_PWTYPE(type) \
344 MODULE_ALIAS("net-l2tp-type-" __stringify(type))
345
James Chapmanfd558d12010-04-02 06:18:33 +0000346#endif /* _L2TP_CORE_H_ */