aboutsummaryrefslogtreecommitdiff
path: root/net/l2tp/l2tp_core.h
blob: 3f93ccd6ba9768fe171f4e35e79d613226c1dbc7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
/*
 * L2TP internal definitions.
 *
 * Copyright (c) 2008,2009 Katalix Systems Ltd
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#ifndef _L2TP_CORE_H_
#define _L2TP_CORE_H_

/* Just some random numbers */
#define L2TP_TUNNEL_MAGIC	0x42114DDA
#define L2TP_SESSION_MAGIC	0x0C04EB7D

/* Per tunnel, session hash table size */
#define L2TP_HASH_BITS	4
#define L2TP_HASH_SIZE	(1 << L2TP_HASH_BITS)

/* System-wide, session hash table size */
#define L2TP_HASH_BITS_2	8
#define L2TP_HASH_SIZE_2	(1 << L2TP_HASH_BITS_2)

/* Debug message categories for the DEBUG socket option */
enum {
	L2TP_MSG_DEBUG		= (1 << 0),	/* verbose debug (if
						 * compiled in) */
	L2TP_MSG_CONTROL	= (1 << 1),	/* userspace - kernel
						 * interface */
	L2TP_MSG_SEQ		= (1 << 2),	/* sequence numbers */
	L2TP_MSG_DATA		= (1 << 3),	/* data packets */
};

struct sk_buff;

struct l2tp_stats {
	atomic_long_t		tx_packets;
	atomic_long_t		tx_bytes;
	atomic_long_t		tx_errors;
	atomic_long_t		rx_packets;
	atomic_long_t		rx_bytes;
	atomic_long_t		rx_seq_discards;
	atomic_long_t		rx_oos_packets;
	atomic_long_t		rx_errors;
	atomic_long_t		rx_cookie_discards;
};

struct l2tp_tunnel;

/* Describes a session. Contains information to determine incoming
 * packets and transmit outgoing ones.
 */
struct l2tp_session_cfg {
	enum l2tp_pwtype	pw_type;
	unsigned int		data_seq:2;	/* data sequencing level
						 * 0 => none, 1 => IP only,
						 * 2 => all
						 */
	unsigned int		recv_seq:1;	/* expect receive packets with
						 * sequence numbers? */
	unsigned int		send_seq:1;	/* send packets with sequence
						 * numbers? */
	unsigned int		lns_mode:1;	/* behave as LNS? LAC enables
						 * sequence numbers under
						 * control of LNS. */
	int			debug;		/* bitmask of debug message
						 * categories */
	u16			vlan_id;	/* VLAN pseudowire only */
	u16			offset;		/* offset to payload */
	u16			l2specific_len;	/* Layer 2 specific length */
	u16			l2specific_type; /* Layer 2 specific type */
	u8			cookie[8];	/* optional cookie */
	int			cookie_len;	/* 0, 4 or 8 bytes */
	u8			peer_cookie[8];	/* peer's cookie */
	int			peer_cookie_len; /* 0, 4 or 8 bytes */
	int			reorder_timeout; /* configured reorder timeout
						  * (in jiffies) */
	int			mtu;
	int			mru;
	char			*ifname;
};

struct l2tp_session {
	int			magic;		/* should be
						 * L2TP_SESSION_MAGIC */

	struct l2tp_tunnel	*tunnel;	/* back pointer to tunnel
						 * context */
	u32			session_id;
	u32			peer_session_id;
	u8			cookie[8];
	int			cookie_len;
	u8			peer_cookie[8];
	int			peer_cookie_len;
	u16			offset;		/* offset from end of L2TP header
						   to beginning of data */
	u16			l2specific_len;
	u16			l2specific_type;
	u16			hdr_len;
	u32			nr;		/* session NR state (receive) */
	u32			ns;		/* session NR state (send) */
	struct sk_buff_head	reorder_q;	/* receive reorder queue */
	u32			nr_max;		/* max NR. Depends on tunnel */
	u32			nr_window_size;	/* NR window size */
	u32			nr_oos;		/* NR of last OOS packet */
	int			nr_oos_count;	/* For OOS recovery */
	int			nr_oos_count_max;
	struct hlist_node	hlist;		/* Hash list node */
	atomic_t		ref_count;

	char			name[32];	/* for logging */
	char			ifname[IFNAMSIZ];
	unsigned int		data_seq:2;	/* data sequencing level
						 * 0 => none, 1 => IP only,
						 * 2 => all
						 */
	unsigned int		recv_seq:1;	/* expect receive packets with
						 * sequence numbers? */
	unsigned int		send_seq:1;	/* send packets with sequence
						 * numbers? */
	unsigned int		lns_mode:1;	/* behave as LNS? LAC enables
						 * sequence numbers under
						 * control of LNS. */
	int			debug;		/* bitmask of debug message
						 * categories */
	int			reorder_timeout; /* configured reorder timeout
						  * (in jiffies) */
	int			reorder_skip;	/* set if skip to next nr */
	int			mtu;
	int			mru;
	enum l2tp_pwtype	pwtype;
	struct l2tp_stats	stats;
	struct hlist_node	global_hlist;	/* Global hash list node */

	int (*build_header)(struct l2tp_session *session, void *buf);
	void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
	void (*session_close)(struct l2tp_session *session);
	void (*ref)(struct l2tp_session *session);
	void (*deref)(struct l2tp_session *session);
#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
	void (*show)(struct seq_file *m, void *priv);
#endif
	uint8_t			priv[0];	/* private data */
};

/* Describes the tunnel. It contains info to track all the associated
 * sessions so incoming packets can be sorted out
 */
struct l2tp_tunnel_cfg {
	int			debug;		/* bitmask of debug message
						 * categories */
	enum l2tp_encap_type	encap;

	/* Used only for kernel-created sockets */
	struct in_addr		local_ip;
	struct in_addr		peer_ip;
#if IS_ENABLED(CONFIG_IPV6)
	struct in6_addr		*local_ip6;
	struct in6_addr		*peer_ip6;
#endif
	u16			local_udp_port;
	u16			peer_udp_port;
	unsigned int		use_udp_checksums:1;
};

struct l2tp_tunnel {
	int			magic;		/* Should be L2TP_TUNNEL_MAGIC */
	struct rcu_head rcu;
	rwlock_t		hlist_lock;	/* protect session_hlist */
	struct hlist_head	session_hlist[L2TP_HASH_SIZE];
						/* hashed list of sessions,
						 * hashed by id */
	u32			tunnel_id;
	u32			peer_tunnel_id;
	int			version;	/* 2=>L2TPv2, 3=>L2TPv3 */

	char			name[20];	/* for logging */
	int			debug;		/* bitmask of debug message
						 * categories */
	enum l2tp_encap_type	encap;
	struct l2tp_stats	stats;

	struct list_head	list;		/* Keep a list of all tunnels */
	struct net		*l2tp_net;	/* the net we belong to */

	atomic_t		ref_count;
#ifdef CONFIG_DEBUG_FS
	void (*show)(struct seq_file *m, void *arg);
#endif
	int (*recv_payload_hook)(struct sk_buff *skb);
	void (*old_sk_destruct)(struct sock *);
	struct sock		*sock;		/* Parent socket */
	int			fd;		/* Parent fd, if tunnel socket
						 * was created by userspace */
#if IS_ENABLED(CONFIG_IPV6)
	bool			v4mapped;
#endif

	struct work_struct	del_work;

	uint8_t			priv[0];	/* private data */
};

struct l2tp_nl_cmd_ops {
	int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
	int (*session_delete)(struct l2tp_session *session);
};

static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
{
	return &tunnel->priv[0];
}

static inline void *l2tp_session_priv(struct l2tp_session *session)
{
	return &session->priv[0];
}

static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
{
	struct l2tp_tunnel *tunnel;

	if (sk == NULL)
		return NULL;

	sock_hold(sk);
	tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
	if (tunnel == NULL) {
		sock_put(sk);
		goto out;
	}

	BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);

out:
	return tunnel;
}

struct l2tp_session *l2tp_session_find(struct net *net,
				       struct l2tp_tunnel *tunnel,
				       u32 session_id);
struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);

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);
void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
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);
void __l2tp_session_unhash(struct l2tp_session *session);
int l2tp_session_delete(struct l2tp_session *session);
void l2tp_session_free(struct l2tp_session *session);
void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
		      unsigned char *ptr, unsigned char *optr, u16 hdrflags,
		      int length, int (*payload_hook)(struct sk_buff *skb));
int l2tp_session_queue_purge(struct l2tp_session *session);
int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
void l2tp_session_set_header_len(struct l2tp_session *session, int version);

int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
		  int hdr_len);

int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
			 const struct l2tp_nl_cmd_ops *ops);
void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);

/* Session reference counts. Incremented when code obtains a reference
 * to a session.
 */
static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
{
	atomic_inc(&session->ref_count);
}

static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
{
	if (atomic_dec_and_test(&session->ref_count))
		l2tp_session_free(session);
}

#ifdef L2TP_REFCNT_DEBUG
#define l2tp_session_inc_refcount(_s)					\
do {									\
	pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",	\
		 __func__, __LINE__, (_s)->name,			\
		 atomic_read(&_s->ref_count));				\
	l2tp_session_inc_refcount_1(_s);				\
} while (0)
#define l2tp_session_dec_refcount(_s)					\
do {									\
	pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",	\
		 __func__, __LINE__, (_s)->name,			\
		 atomic_read(&_s->ref_count));				\
	l2tp_session_dec_refcount_1(_s);				\
} while (0)
#else
#define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
#define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
#endif

#define l2tp_printk(ptr, type, func, fmt, ...)				\
do {									\
	if (((ptr)->debug) & (type))					\
		func(fmt, ##__VA_ARGS__);				\
} while (0)

#define l2tp_warn(ptr, type, fmt, ...)					\
	l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
#define l2tp_info(ptr, type, fmt, ...)					\
	l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
#define l2tp_dbg(ptr, type, fmt, ...)					\
	l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)

#endif /* _L2TP_CORE_H_ */