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 #include <net/dst.h>
16 #include <net/sock.h>
17
18 #ifdef CONFIG_XFRM
19 #include <net/xfrm.h>
20 #endif
21
22 /* Just some random numbers */
23 #define L2TP_TUNNEL_MAGIC 0x42114DDA
24 #define L2TP_SESSION_MAGIC 0x0C04EB7D
25
26 /* Per tunnel, session hash table size */
27 #define L2TP_HASH_BITS 4
28 #define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS)
29
30 /* System-wide, session hash table size */
31 #define L2TP_HASH_BITS_2 8
32 #define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2)
33
34 struct sk_buff;
35
36 struct l2tp_stats {
37 atomic_long_t tx_packets;
38 atomic_long_t tx_bytes;
39 atomic_long_t tx_errors;
40 atomic_long_t rx_packets;
41 atomic_long_t rx_bytes;
42 atomic_long_t rx_seq_discards;
43 atomic_long_t rx_oos_packets;
44 atomic_long_t rx_errors;
45 atomic_long_t rx_cookie_discards;
46 };
47
48 struct l2tp_tunnel;
49
50 /* Describes a session. Contains information to determine incoming
51 * packets and transmit outgoing ones.
52 */
53 struct l2tp_session_cfg {
54 enum l2tp_pwtype pw_type;
55 unsigned int recv_seq:1; /* expect receive packets with
56 * sequence numbers? */
57 unsigned int send_seq:1; /* send packets with sequence
58 * numbers? */
59 unsigned int lns_mode:1; /* behave as LNS? LAC enables
60 * sequence numbers under
61 * control of LNS. */
62 int debug; /* bitmask of debug message
63 * categories */
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 char *ifname;
72 };
73
74 struct l2tp_session {
75 int magic; /* should be
76 * L2TP_SESSION_MAGIC */
77 long dead;
78
79 struct l2tp_tunnel *tunnel; /* back pointer to tunnel
80 * context */
81 u32 session_id;
82 u32 peer_session_id;
83 u8 cookie[8];
84 int cookie_len;
85 u8 peer_cookie[8];
86 int peer_cookie_len;
87 u16 l2specific_type;
88 u16 hdr_len;
89 u32 nr; /* session NR state (receive) */
90 u32 ns; /* session NR state (send) */
91 struct sk_buff_head reorder_q; /* receive reorder queue */
92 u32 nr_max; /* max NR. Depends on tunnel */
93 u32 nr_window_size; /* NR window size */
94 u32 nr_oos; /* NR of last OOS packet */
95 int nr_oos_count; /* For OOS recovery */
96 int nr_oos_count_max;
97 struct hlist_node hlist; /* Hash list node */
98 refcount_t ref_count;
99
100 char name[32]; /* for logging */
101 char ifname[IFNAMSIZ];
102 unsigned int recv_seq:1; /* expect receive packets with
103 * sequence numbers? */
104 unsigned int send_seq:1; /* send packets with sequence
105 * numbers? */
106 unsigned int lns_mode:1; /* behave as LNS? LAC enables
107 * sequence numbers under
108 * control of LNS. */
109 int debug; /* bitmask of debug message
110 * categories */
111 int reorder_timeout; /* configured reorder timeout
112 * (in jiffies) */
113 int reorder_skip; /* set if skip to next nr */
114 enum l2tp_pwtype pwtype;
115 struct l2tp_stats stats;
116 struct hlist_node global_hlist; /* Global hash list node */
117
118 int (*build_header)(struct l2tp_session *session, void *buf);
119 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
120 void (*session_close)(struct l2tp_session *session);
121 void (*show)(struct seq_file *m, void *priv);
122 uint8_t priv[0]; /* private data */
123 };
124
125 /* Describes the tunnel. It contains info to track all the associated
126 * sessions so incoming packets can be sorted out
127 */
128 struct l2tp_tunnel_cfg {
129 int debug; /* bitmask of debug message
130 * categories */
131 enum l2tp_encap_type encap;
132
133 /* Used only for kernel-created sockets */
134 struct in_addr local_ip;
135 struct in_addr peer_ip;
136 #if IS_ENABLED(CONFIG_IPV6)
137 struct in6_addr *local_ip6;
138 struct in6_addr *peer_ip6;
139 #endif
140 u16 local_udp_port;
141 u16 peer_udp_port;
142 unsigned int use_udp_checksums:1,
143 udp6_zero_tx_checksums:1,
144 udp6_zero_rx_checksums:1;
145 };
146
147 struct l2tp_tunnel {
148 int magic; /* Should be L2TP_TUNNEL_MAGIC */
149
150 unsigned long dead;
151
152 struct rcu_head rcu;
153 rwlock_t hlist_lock; /* protect session_hlist */
154 bool acpt_newsess; /* Indicates whether this
155 * tunnel accepts new sessions.
156 * Protected by hlist_lock.
157 */
158 struct hlist_head session_hlist[L2TP_HASH_SIZE];
159 /* hashed list of sessions,
160 * hashed by id */
161 u32 tunnel_id;
162 u32 peer_tunnel_id;
163 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
164
165 char name[20]; /* for logging */
166 int debug; /* bitmask of debug message
167 * categories */
168 enum l2tp_encap_type encap;
169 struct l2tp_stats stats;
170
171 struct list_head list; /* Keep a list of all tunnels */
172 struct net *l2tp_net; /* the net we belong to */
173
174 refcount_t ref_count;
175 void (*old_sk_destruct)(struct sock *);
176 struct sock *sock; /* Parent socket */
177 int fd; /* Parent fd, if tunnel socket
178 * was created by userspace */
179
180 struct work_struct del_work;
181 };
182
183 struct l2tp_nl_cmd_ops {
184 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
185 u32 session_id, u32 peer_session_id,
186 struct l2tp_session_cfg *cfg);
187 int (*session_delete)(struct l2tp_session *session);
188 };
189
l2tp_session_priv(struct l2tp_session * session)190 static inline void *l2tp_session_priv(struct l2tp_session *session)
191 {
192 return &session->priv[0];
193 }
194
195 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
196 struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth);
197 struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel,
198 u32 session_id);
199
200 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
201
202 struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id);
203 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
204 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
205 const char *ifname);
206
207 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
208 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
209 struct l2tp_tunnel **tunnelp);
210 int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
211 struct l2tp_tunnel_cfg *cfg);
212
213 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
214 struct l2tp_session *l2tp_session_create(int priv_size,
215 struct l2tp_tunnel *tunnel,
216 u32 session_id, u32 peer_session_id,
217 struct l2tp_session_cfg *cfg);
218 int l2tp_session_register(struct l2tp_session *session,
219 struct l2tp_tunnel *tunnel);
220
221 void __l2tp_session_unhash(struct l2tp_session *session);
222 int l2tp_session_delete(struct l2tp_session *session);
223 void l2tp_session_free(struct l2tp_session *session);
224 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
225 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
226 int length);
227 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
228 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
229
230 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
231 int hdr_len);
232
233 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
234 const struct l2tp_nl_cmd_ops *ops);
235 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
236 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
237
l2tp_tunnel_inc_refcount(struct l2tp_tunnel * tunnel)238 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
239 {
240 refcount_inc(&tunnel->ref_count);
241 }
242
l2tp_tunnel_dec_refcount(struct l2tp_tunnel * tunnel)243 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
244 {
245 if (refcount_dec_and_test(&tunnel->ref_count))
246 l2tp_tunnel_free(tunnel);
247 }
248
249 /* Session reference counts. Incremented when code obtains a reference
250 * to a session.
251 */
l2tp_session_inc_refcount(struct l2tp_session * session)252 static inline void l2tp_session_inc_refcount(struct l2tp_session *session)
253 {
254 refcount_inc(&session->ref_count);
255 }
256
l2tp_session_dec_refcount(struct l2tp_session * session)257 static inline void l2tp_session_dec_refcount(struct l2tp_session *session)
258 {
259 if (refcount_dec_and_test(&session->ref_count))
260 l2tp_session_free(session);
261 }
262
l2tp_get_l2specific_len(struct l2tp_session * session)263 static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
264 {
265 switch (session->l2specific_type) {
266 case L2TP_L2SPECTYPE_DEFAULT:
267 return 4;
268 case L2TP_L2SPECTYPE_NONE:
269 default:
270 return 0;
271 }
272 }
273
l2tp_tunnel_dst_mtu(const struct l2tp_tunnel * tunnel)274 static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel)
275 {
276 struct dst_entry *dst;
277 u32 mtu;
278
279 dst = sk_dst_get(tunnel->sock);
280 if (!dst)
281 return 0;
282
283 mtu = dst_mtu(dst);
284 dst_release(dst);
285
286 return mtu;
287 }
288
289 #ifdef CONFIG_XFRM
l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel * tunnel)290 static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
291 {
292 struct sock *sk = tunnel->sock;
293
294 return sk && (rcu_access_pointer(sk->sk_policy[0]) ||
295 rcu_access_pointer(sk->sk_policy[1]));
296 }
297 #else
l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel * tunnel)298 static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
299 {
300 return false;
301 }
302 #endif
303
304 #define l2tp_printk(ptr, type, func, fmt, ...) \
305 do { \
306 if (((ptr)->debug) & (type)) \
307 func(fmt, ##__VA_ARGS__); \
308 } while (0)
309
310 #define l2tp_warn(ptr, type, fmt, ...) \
311 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
312 #define l2tp_info(ptr, type, fmt, ...) \
313 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
314 #define l2tp_dbg(ptr, type, fmt, ...) \
315 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
316
317 #define MODULE_ALIAS_L2TP_PWTYPE(type) \
318 MODULE_ALIAS("net-l2tp-type-" __stringify(type))
319
320 #endif /* _L2TP_CORE_H_ */
321
