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 l2specific_len; /* Layer 2 specific length */
63 u16 l2specific_type; /* Layer 2 specific type */
64 u8 cookie[8]; /* optional cookie */
65 int cookie_len; /* 0, 4 or 8 bytes */
66 u8 peer_cookie[8]; /* peer's cookie */
67 int peer_cookie_len; /* 0, 4 or 8 bytes */
68 int reorder_timeout; /* configured reorder timeout
69 * (in jiffies) */
70 int mtu;
71 int mru;
72 char *ifname;
73 };
74
75 struct l2tp_session {
76 int magic; /* should be
77 * L2TP_SESSION_MAGIC */
78 long dead;
79
80 struct l2tp_tunnel *tunnel; /* back pointer to tunnel
81 * context */
82 u32 session_id;
83 u32 peer_session_id;
84 u8 cookie[8];
85 int cookie_len;
86 u8 peer_cookie[8];
87 int peer_cookie_len;
88 u16 l2specific_len;
89 u16 l2specific_type;
90 u16 hdr_len;
91 u32 nr; /* session NR state (receive) */
92 u32 ns; /* session NR state (send) */
93 struct sk_buff_head reorder_q; /* receive reorder queue */
94 u32 nr_max; /* max NR. Depends on tunnel */
95 u32 nr_window_size; /* NR window size */
96 u32 nr_oos; /* NR of last OOS packet */
97 int nr_oos_count; /* For OOS recovery */
98 int nr_oos_count_max;
99 struct hlist_node hlist; /* Hash list node */
100 refcount_t ref_count;
101
102 char name[32]; /* for logging */
103 char ifname[IFNAMSIZ];
104 unsigned int data_seq:2; /* data sequencing level
105 * 0 => none, 1 => IP only,
106 * 2 => all
107 */
108 unsigned int recv_seq:1; /* expect receive packets with
109 * sequence numbers? */
110 unsigned int send_seq:1; /* send packets with sequence
111 * numbers? */
112 unsigned int lns_mode:1; /* behave as LNS? LAC enables
113 * sequence numbers under
114 * control of LNS. */
115 int debug; /* bitmask of debug message
116 * categories */
117 int reorder_timeout; /* configured reorder timeout
118 * (in jiffies) */
119 int reorder_skip; /* set if skip to next nr */
120 int mtu;
121 int mru;
122 enum l2tp_pwtype pwtype;
123 struct l2tp_stats stats;
124 struct hlist_node global_hlist; /* Global hash list node */
125
126 int (*build_header)(struct l2tp_session *session, void *buf);
127 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
128 void (*session_close)(struct l2tp_session *session);
129 void (*ref)(struct l2tp_session *session);
130 void (*deref)(struct l2tp_session *session);
131 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
132 void (*show)(struct seq_file *m, void *priv);
133 #endif
134 uint8_t priv[0]; /* private data */
135 };
136
137 /* Describes the tunnel. It contains info to track all the associated
138 * sessions so incoming packets can be sorted out
139 */
140 struct l2tp_tunnel_cfg {
141 int debug; /* bitmask of debug message
142 * categories */
143 enum l2tp_encap_type encap;
144
145 /* Used only for kernel-created sockets */
146 struct in_addr local_ip;
147 struct in_addr peer_ip;
148 #if IS_ENABLED(CONFIG_IPV6)
149 struct in6_addr *local_ip6;
150 struct in6_addr *peer_ip6;
151 #endif
152 u16 local_udp_port;
153 u16 peer_udp_port;
154 unsigned int use_udp_checksums:1,
155 udp6_zero_tx_checksums:1,
156 udp6_zero_rx_checksums:1;
157 };
158
159 struct l2tp_tunnel {
160 int magic; /* Should be L2TP_TUNNEL_MAGIC */
161
162 unsigned long dead;
163
164 struct rcu_head rcu;
165 rwlock_t hlist_lock; /* protect session_hlist */
166 bool acpt_newsess; /* Indicates whether this
167 * tunnel accepts new sessions.
168 * Protected by hlist_lock.
169 */
170 struct hlist_head session_hlist[L2TP_HASH_SIZE];
171 /* hashed list of sessions,
172 * hashed by id */
173 u32 tunnel_id;
174 u32 peer_tunnel_id;
175 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
176
177 char name[20]; /* for logging */
178 int debug; /* bitmask of debug message
179 * categories */
180 enum l2tp_encap_type encap;
181 struct l2tp_stats stats;
182
183 struct list_head list; /* Keep a list of all tunnels */
184 struct net *l2tp_net; /* the net we belong to */
185
186 refcount_t ref_count;
187 #ifdef CONFIG_DEBUG_FS
188 void (*show)(struct seq_file *m, void *arg);
189 #endif
190 void (*old_sk_destruct)(struct sock *);
191 struct sock *sock; /* Parent socket */
192 int fd; /* Parent fd, if tunnel socket
193 * was created by userspace */
194
195 struct work_struct del_work;
196
197 uint8_t priv[0]; /* private data */
198 };
199
200 struct l2tp_nl_cmd_ops {
201 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
202 u32 session_id, u32 peer_session_id,
203 struct l2tp_session_cfg *cfg);
204 int (*session_delete)(struct l2tp_session *session);
205 };
206
l2tp_tunnel_priv(struct l2tp_tunnel * tunnel)207 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
208 {
209 return &tunnel->priv[0];
210 }
211
l2tp_session_priv(struct l2tp_session * session)212 static inline void *l2tp_session_priv(struct l2tp_session *session)
213 {
214 return &session->priv[0];
215 }
216
l2tp_sock_to_tunnel(struct sock * sk)217 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
218 {
219 struct l2tp_tunnel *tunnel;
220
221 if (sk == NULL)
222 return NULL;
223
224 sock_hold(sk);
225 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
226 if (tunnel == NULL) {
227 sock_put(sk);
228 goto out;
229 }
230
231 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
232
233 out:
234 return tunnel;
235 }
236
237 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
238
239 struct l2tp_session *l2tp_session_get(const struct net *net,
240 struct l2tp_tunnel *tunnel,
241 u32 session_id, bool do_ref);
242 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
243 bool do_ref);
244 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
245 const char *ifname,
246 bool do_ref);
247 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id);
248 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
249
250 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
251 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
252 struct l2tp_tunnel **tunnelp);
253 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
254 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
255 struct l2tp_session *l2tp_session_create(int priv_size,
256 struct l2tp_tunnel *tunnel,
257 u32 session_id, u32 peer_session_id,
258 struct l2tp_session_cfg *cfg);
259 void __l2tp_session_unhash(struct l2tp_session *session);
260 int l2tp_session_delete(struct l2tp_session *session);
261 void l2tp_session_free(struct l2tp_session *session);
262 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
263 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
264 int length);
265 int l2tp_session_queue_purge(struct l2tp_session *session);
266 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
267 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
268
269 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
270 int hdr_len);
271
272 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
273 const struct l2tp_nl_cmd_ops *ops);
274 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
275 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
276
l2tp_tunnel_inc_refcount(struct l2tp_tunnel * tunnel)277 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
278 {
279 refcount_inc(&tunnel->ref_count);
280 }
281
l2tp_tunnel_dec_refcount(struct l2tp_tunnel * tunnel)282 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
283 {
284 if (refcount_dec_and_test(&tunnel->ref_count))
285 kfree_rcu(tunnel, rcu);
286 }
287
288 /* Session reference counts. Incremented when code obtains a reference
289 * to a session.
290 */
l2tp_session_inc_refcount_1(struct l2tp_session * session)291 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
292 {
293 refcount_inc(&session->ref_count);
294 }
295
l2tp_session_dec_refcount_1(struct l2tp_session * session)296 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
297 {
298 if (refcount_dec_and_test(&session->ref_count))
299 l2tp_session_free(session);
300 }
301
302 #ifdef L2TP_REFCNT_DEBUG
303 #define l2tp_session_inc_refcount(_s) \
304 do { \
305 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \
306 __func__, __LINE__, (_s)->name, \
307 refcount_read(&_s->ref_count)); \
308 l2tp_session_inc_refcount_1(_s); \
309 } while (0)
310 #define l2tp_session_dec_refcount(_s) \
311 do { \
312 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \
313 __func__, __LINE__, (_s)->name, \
314 refcount_read(&_s->ref_count)); \
315 l2tp_session_dec_refcount_1(_s); \
316 } while (0)
317 #else
318 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
319 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
320 #endif
321
l2tp_get_l2specific_len(struct l2tp_session * session)322 static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
323 {
324 switch (session->l2specific_type) {
325 case L2TP_L2SPECTYPE_DEFAULT:
326 return 4;
327 case L2TP_L2SPECTYPE_NONE:
328 default:
329 return 0;
330 }
331 }
332
l2tp_v3_ensure_opt_in_linear(struct l2tp_session * session,struct sk_buff * skb,unsigned char ** ptr,unsigned char ** optr)333 static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb,
334 unsigned char **ptr, unsigned char **optr)
335 {
336 int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session);
337
338 if (opt_len > 0) {
339 int off = *ptr - *optr;
340
341 if (!pskb_may_pull(skb, off + opt_len))
342 return -1;
343
344 if (skb->data != *optr) {
345 *optr = skb->data;
346 *ptr = skb->data + off;
347 }
348 }
349
350 return 0;
351 }
352
353 #define l2tp_printk(ptr, type, func, fmt, ...) \
354 do { \
355 if (((ptr)->debug) & (type)) \
356 func(fmt, ##__VA_ARGS__); \
357 } while (0)
358
359 #define l2tp_warn(ptr, type, fmt, ...) \
360 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
361 #define l2tp_info(ptr, type, fmt, ...) \
362 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
363 #define l2tp_dbg(ptr, type, fmt, ...) \
364 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
365
366 #define MODULE_ALIAS_L2TP_PWTYPE(type) \
367 MODULE_ALIAS("net-l2tp-type-" __stringify(type))
368
369 #endif /* _L2TP_CORE_H_ */
370