xref: /openbmc/linux/net/l2tp/l2tp_core.h (revision 6aa7de05)
1 /*
2  * L2TP internal definitions.
3  *
4  * Copyright (c) 2008,2009 Katalix Systems Ltd
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 #include <linux/refcount.h>
11 
12 #ifndef _L2TP_CORE_H_
13 #define _L2TP_CORE_H_
14 
15 /* Just some random numbers */
16 #define L2TP_TUNNEL_MAGIC	0x42114DDA
17 #define L2TP_SESSION_MAGIC	0x0C04EB7D
18 
19 /* Per tunnel, session hash table size */
20 #define L2TP_HASH_BITS	4
21 #define L2TP_HASH_SIZE	(1 << L2TP_HASH_BITS)
22 
23 /* System-wide, session hash table size */
24 #define L2TP_HASH_BITS_2	8
25 #define L2TP_HASH_SIZE_2	(1 << L2TP_HASH_BITS_2)
26 
27 struct sk_buff;
28 
29 struct l2tp_stats {
30 	atomic_long_t		tx_packets;
31 	atomic_long_t		tx_bytes;
32 	atomic_long_t		tx_errors;
33 	atomic_long_t		rx_packets;
34 	atomic_long_t		rx_bytes;
35 	atomic_long_t		rx_seq_discards;
36 	atomic_long_t		rx_oos_packets;
37 	atomic_long_t		rx_errors;
38 	atomic_long_t		rx_cookie_discards;
39 };
40 
41 struct l2tp_tunnel;
42 
43 /* Describes a session. Contains information to determine incoming
44  * packets and transmit outgoing ones.
45  */
46 struct l2tp_session_cfg {
47 	enum l2tp_pwtype	pw_type;
48 	unsigned int		data_seq:2;	/* data sequencing level
49 						 * 0 => none, 1 => IP only,
50 						 * 2 => all
51 						 */
52 	unsigned int		recv_seq:1;	/* expect receive packets with
53 						 * sequence numbers? */
54 	unsigned int		send_seq:1;	/* send packets with sequence
55 						 * numbers? */
56 	unsigned int		lns_mode:1;	/* behave as LNS? LAC enables
57 						 * sequence numbers under
58 						 * control of LNS. */
59 	int			debug;		/* bitmask of debug message
60 						 * categories */
61 	u16			vlan_id;	/* VLAN pseudowire only */
62 	u16			offset;		/* offset to payload */
63 	u16			l2specific_len;	/* Layer 2 specific length */
64 	u16			l2specific_type; /* Layer 2 specific type */
65 	u8			cookie[8];	/* optional cookie */
66 	int			cookie_len;	/* 0, 4 or 8 bytes */
67 	u8			peer_cookie[8];	/* peer's cookie */
68 	int			peer_cookie_len; /* 0, 4 or 8 bytes */
69 	int			reorder_timeout; /* configured reorder timeout
70 						  * (in jiffies) */
71 	int			mtu;
72 	int			mru;
73 	char			*ifname;
74 };
75 
76 struct l2tp_session {
77 	int			magic;		/* should be
78 						 * L2TP_SESSION_MAGIC */
79 	long			dead;
80 
81 	struct l2tp_tunnel	*tunnel;	/* back pointer to tunnel
82 						 * context */
83 	u32			session_id;
84 	u32			peer_session_id;
85 	u8			cookie[8];
86 	int			cookie_len;
87 	u8			peer_cookie[8];
88 	int			peer_cookie_len;
89 	u16			offset;		/* offset from end of L2TP header
90 						   to beginning of data */
91 	u16			l2specific_len;
92 	u16			l2specific_type;
93 	u16			hdr_len;
94 	u32			nr;		/* session NR state (receive) */
95 	u32			ns;		/* session NR state (send) */
96 	struct sk_buff_head	reorder_q;	/* receive reorder queue */
97 	u32			nr_max;		/* max NR. Depends on tunnel */
98 	u32			nr_window_size;	/* NR window size */
99 	u32			nr_oos;		/* NR of last OOS packet */
100 	int			nr_oos_count;	/* For OOS recovery */
101 	int			nr_oos_count_max;
102 	struct hlist_node	hlist;		/* Hash list node */
103 	refcount_t		ref_count;
104 
105 	char			name[32];	/* for logging */
106 	char			ifname[IFNAMSIZ];
107 	unsigned int		data_seq:2;	/* data sequencing level
108 						 * 0 => none, 1 => IP only,
109 						 * 2 => all
110 						 */
111 	unsigned int		recv_seq:1;	/* expect receive packets with
112 						 * sequence numbers? */
113 	unsigned int		send_seq:1;	/* send packets with sequence
114 						 * numbers? */
115 	unsigned int		lns_mode:1;	/* behave as LNS? LAC enables
116 						 * sequence numbers under
117 						 * control of LNS. */
118 	int			debug;		/* bitmask of debug message
119 						 * categories */
120 	int			reorder_timeout; /* configured reorder timeout
121 						  * (in jiffies) */
122 	int			reorder_skip;	/* set if skip to next nr */
123 	int			mtu;
124 	int			mru;
125 	enum l2tp_pwtype	pwtype;
126 	struct l2tp_stats	stats;
127 	struct hlist_node	global_hlist;	/* Global hash list node */
128 
129 	int (*build_header)(struct l2tp_session *session, void *buf);
130 	void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
131 	void (*session_close)(struct l2tp_session *session);
132 	void (*ref)(struct l2tp_session *session);
133 	void (*deref)(struct l2tp_session *session);
134 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
135 	void (*show)(struct seq_file *m, void *priv);
136 #endif
137 	uint8_t			priv[0];	/* private data */
138 };
139 
140 /* Describes the tunnel. It contains info to track all the associated
141  * sessions so incoming packets can be sorted out
142  */
143 struct l2tp_tunnel_cfg {
144 	int			debug;		/* bitmask of debug message
145 						 * categories */
146 	enum l2tp_encap_type	encap;
147 
148 	/* Used only for kernel-created sockets */
149 	struct in_addr		local_ip;
150 	struct in_addr		peer_ip;
151 #if IS_ENABLED(CONFIG_IPV6)
152 	struct in6_addr		*local_ip6;
153 	struct in6_addr		*peer_ip6;
154 #endif
155 	u16			local_udp_port;
156 	u16			peer_udp_port;
157 	unsigned int		use_udp_checksums:1,
158 				udp6_zero_tx_checksums:1,
159 				udp6_zero_rx_checksums:1;
160 };
161 
162 struct l2tp_tunnel {
163 	int			magic;		/* Should be L2TP_TUNNEL_MAGIC */
164 
165 	unsigned long		dead;
166 
167 	struct rcu_head rcu;
168 	rwlock_t		hlist_lock;	/* protect session_hlist */
169 	bool			acpt_newsess;	/* Indicates whether this
170 						 * tunnel accepts new sessions.
171 						 * Protected by hlist_lock.
172 						 */
173 	struct hlist_head	session_hlist[L2TP_HASH_SIZE];
174 						/* hashed list of sessions,
175 						 * hashed by id */
176 	u32			tunnel_id;
177 	u32			peer_tunnel_id;
178 	int			version;	/* 2=>L2TPv2, 3=>L2TPv3 */
179 
180 	char			name[20];	/* for logging */
181 	int			debug;		/* bitmask of debug message
182 						 * categories */
183 	enum l2tp_encap_type	encap;
184 	struct l2tp_stats	stats;
185 
186 	struct list_head	list;		/* Keep a list of all tunnels */
187 	struct net		*l2tp_net;	/* the net we belong to */
188 
189 	refcount_t		ref_count;
190 #ifdef CONFIG_DEBUG_FS
191 	void (*show)(struct seq_file *m, void *arg);
192 #endif
193 	int (*recv_payload_hook)(struct sk_buff *skb);
194 	void (*old_sk_destruct)(struct sock *);
195 	struct sock		*sock;		/* Parent socket */
196 	int			fd;		/* Parent fd, if tunnel socket
197 						 * was created by userspace */
198 #if IS_ENABLED(CONFIG_IPV6)
199 	bool			v4mapped;
200 #endif
201 
202 	struct work_struct	del_work;
203 
204 	uint8_t			priv[0];	/* private data */
205 };
206 
207 struct l2tp_nl_cmd_ops {
208 	int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
209 			      u32 session_id, u32 peer_session_id,
210 			      struct l2tp_session_cfg *cfg);
211 	int (*session_delete)(struct l2tp_session *session);
212 };
213 
214 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
215 {
216 	return &tunnel->priv[0];
217 }
218 
219 static inline void *l2tp_session_priv(struct l2tp_session *session)
220 {
221 	return &session->priv[0];
222 }
223 
224 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
225 {
226 	struct l2tp_tunnel *tunnel;
227 
228 	if (sk == NULL)
229 		return NULL;
230 
231 	sock_hold(sk);
232 	tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
233 	if (tunnel == NULL) {
234 		sock_put(sk);
235 		goto out;
236 	}
237 
238 	BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
239 
240 out:
241 	return tunnel;
242 }
243 
244 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
245 
246 struct l2tp_session *l2tp_session_get(const struct net *net,
247 				      struct l2tp_tunnel *tunnel,
248 				      u32 session_id, bool do_ref);
249 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
250 					  bool do_ref);
251 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
252 						const char *ifname,
253 						bool do_ref);
254 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id);
255 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
256 
257 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
258 		       u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
259 		       struct l2tp_tunnel **tunnelp);
260 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
261 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
262 struct l2tp_session *l2tp_session_create(int priv_size,
263 					 struct l2tp_tunnel *tunnel,
264 					 u32 session_id, u32 peer_session_id,
265 					 struct l2tp_session_cfg *cfg);
266 void __l2tp_session_unhash(struct l2tp_session *session);
267 int l2tp_session_delete(struct l2tp_session *session);
268 void l2tp_session_free(struct l2tp_session *session);
269 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
270 		      unsigned char *ptr, unsigned char *optr, u16 hdrflags,
271 		      int length, int (*payload_hook)(struct sk_buff *skb));
272 int l2tp_session_queue_purge(struct l2tp_session *session);
273 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
274 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
275 
276 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
277 		  int hdr_len);
278 
279 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
280 			 const struct l2tp_nl_cmd_ops *ops);
281 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
282 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
283 
284 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
285 {
286 	refcount_inc(&tunnel->ref_count);
287 }
288 
289 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
290 {
291 	if (refcount_dec_and_test(&tunnel->ref_count))
292 		kfree_rcu(tunnel, rcu);
293 }
294 
295 /* Session reference counts. Incremented when code obtains a reference
296  * to a session.
297  */
298 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
299 {
300 	refcount_inc(&session->ref_count);
301 }
302 
303 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
304 {
305 	if (refcount_dec_and_test(&session->ref_count))
306 		l2tp_session_free(session);
307 }
308 
309 #ifdef L2TP_REFCNT_DEBUG
310 #define l2tp_session_inc_refcount(_s)					\
311 do {									\
312 	pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",	\
313 		 __func__, __LINE__, (_s)->name,			\
314 		 refcount_read(&_s->ref_count));			\
315 	l2tp_session_inc_refcount_1(_s);				\
316 } while (0)
317 #define l2tp_session_dec_refcount(_s)					\
318 do {									\
319 	pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",	\
320 		 __func__, __LINE__, (_s)->name,			\
321 		 refcount_read(&_s->ref_count));			\
322 	l2tp_session_dec_refcount_1(_s);				\
323 } while (0)
324 #else
325 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
326 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
327 #endif
328 
329 #define l2tp_printk(ptr, type, func, fmt, ...)				\
330 do {									\
331 	if (((ptr)->debug) & (type))					\
332 		func(fmt, ##__VA_ARGS__);				\
333 } while (0)
334 
335 #define l2tp_warn(ptr, type, fmt, ...)					\
336 	l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
337 #define l2tp_info(ptr, type, fmt, ...)					\
338 	l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
339 #define l2tp_dbg(ptr, type, fmt, ...)					\
340 	l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
341 
342 #define MODULE_ALIAS_L2TP_PWTYPE(type) \
343 	MODULE_ALIAS("net-l2tp-type-" __stringify(type))
344 
345 #endif /* _L2TP_CORE_H_ */
346