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
11 #ifndef _L2TP_CORE_H_
12 #define _L2TP_CORE_H_
13
14 /* Just some random numbers */
15 #define L2TP_TUNNEL_MAGIC 0x42114DDA
16 #define L2TP_SESSION_MAGIC 0x0C04EB7D
17
18 /* Per tunnel, session hash table size */
19 #define L2TP_HASH_BITS 4
20 #define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS)
21
22 /* System-wide, session hash table size */
23 #define L2TP_HASH_BITS_2 8
24 #define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2)
25
26 /* Debug message categories for the DEBUG socket option */
27 enum {
28 L2TP_MSG_DEBUG = (1 << 0), /* verbose debug (if
29 * compiled in) */
30 L2TP_MSG_CONTROL = (1 << 1), /* userspace - kernel
31 * interface */
32 L2TP_MSG_SEQ = (1 << 2), /* sequence numbers */
33 L2TP_MSG_DATA = (1 << 3), /* data packets */
34 };
35
36 struct sk_buff;
37
38 struct l2tp_stats {
39 atomic_long_t tx_packets;
40 atomic_long_t tx_bytes;
41 atomic_long_t tx_errors;
42 atomic_long_t rx_packets;
43 atomic_long_t rx_bytes;
44 atomic_long_t rx_seq_discards;
45 atomic_long_t rx_oos_packets;
46 atomic_long_t rx_errors;
47 atomic_long_t rx_cookie_discards;
48 };
49
50 struct l2tp_tunnel;
51
52 /* Describes a session. Contains information to determine incoming
53 * packets and transmit outgoing ones.
54 */
55 struct l2tp_session_cfg {
56 enum l2tp_pwtype pw_type;
57 unsigned int data_seq:2; /* data sequencing level
58 * 0 => none, 1 => IP only,
59 * 2 => all
60 */
61 unsigned int recv_seq:1; /* expect receive packets with
62 * sequence numbers? */
63 unsigned int send_seq:1; /* send packets with sequence
64 * numbers? */
65 unsigned int lns_mode:1; /* behave as LNS? LAC enables
66 * sequence numbers under
67 * control of LNS. */
68 int debug; /* bitmask of debug message
69 * categories */
70 u16 vlan_id; /* VLAN pseudowire only */
71 u16 offset; /* offset to payload */
72 u16 l2specific_len; /* Layer 2 specific length */
73 u16 l2specific_type; /* Layer 2 specific type */
74 u8 cookie[8]; /* optional cookie */
75 int cookie_len; /* 0, 4 or 8 bytes */
76 u8 peer_cookie[8]; /* peer's cookie */
77 int peer_cookie_len; /* 0, 4 or 8 bytes */
78 int reorder_timeout; /* configured reorder timeout
79 * (in jiffies) */
80 int mtu;
81 int mru;
82 char *ifname;
83 };
84
85 struct l2tp_session {
86 int magic; /* should be
87 * L2TP_SESSION_MAGIC */
88
89 struct l2tp_tunnel *tunnel; /* back pointer to tunnel
90 * context */
91 u32 session_id;
92 u32 peer_session_id;
93 u8 cookie[8];
94 int cookie_len;
95 u8 peer_cookie[8];
96 int peer_cookie_len;
97 u16 offset; /* offset from end of L2TP header
98 to beginning of data */
99 u16 l2specific_len;
100 u16 l2specific_type;
101 u16 hdr_len;
102 u32 nr; /* session NR state (receive) */
103 u32 ns; /* session NR state (send) */
104 struct sk_buff_head reorder_q; /* receive reorder queue */
105 u32 nr_max; /* max NR. Depends on tunnel */
106 u32 nr_window_size; /* NR window size */
107 u32 nr_oos; /* NR of last OOS packet */
108 int nr_oos_count; /* For OOS recovery */
109 int nr_oos_count_max;
110 struct hlist_node hlist; /* Hash list node */
111 atomic_t ref_count;
112
113 char name[32]; /* for logging */
114 char ifname[IFNAMSIZ];
115 unsigned int data_seq:2; /* data sequencing level
116 * 0 => none, 1 => IP only,
117 * 2 => all
118 */
119 unsigned int recv_seq:1; /* expect receive packets with
120 * sequence numbers? */
121 unsigned int send_seq:1; /* send packets with sequence
122 * numbers? */
123 unsigned int lns_mode:1; /* behave as LNS? LAC enables
124 * sequence numbers under
125 * control of LNS. */
126 int debug; /* bitmask of debug message
127 * categories */
128 int reorder_timeout; /* configured reorder timeout
129 * (in jiffies) */
130 int reorder_skip; /* set if skip to next nr */
131 int mtu;
132 int mru;
133 enum l2tp_pwtype pwtype;
134 struct l2tp_stats stats;
135 struct hlist_node global_hlist; /* Global hash list node */
136
137 int (*build_header)(struct l2tp_session *session, void *buf);
138 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
139 void (*session_close)(struct l2tp_session *session);
140 void (*ref)(struct l2tp_session *session);
141 void (*deref)(struct l2tp_session *session);
142 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
143 void (*show)(struct seq_file *m, void *priv);
144 #endif
145 uint8_t priv[0]; /* private data */
146 };
147
148 /* Describes the tunnel. It contains info to track all the associated
149 * sessions so incoming packets can be sorted out
150 */
151 struct l2tp_tunnel_cfg {
152 int debug; /* bitmask of debug message
153 * categories */
154 enum l2tp_encap_type encap;
155
156 /* Used only for kernel-created sockets */
157 struct in_addr local_ip;
158 struct in_addr peer_ip;
159 #if IS_ENABLED(CONFIG_IPV6)
160 struct in6_addr *local_ip6;
161 struct in6_addr *peer_ip6;
162 #endif
163 u16 local_udp_port;
164 u16 peer_udp_port;
165 unsigned int use_udp_checksums:1,
166 udp6_zero_tx_checksums:1,
167 udp6_zero_rx_checksums:1;
168 };
169
170 struct l2tp_tunnel {
171 int magic; /* Should be L2TP_TUNNEL_MAGIC */
172
173 unsigned long dead;
174
175 struct rcu_head rcu;
176 rwlock_t hlist_lock; /* protect session_hlist */
177 struct hlist_head session_hlist[L2TP_HASH_SIZE];
178 /* hashed list of sessions,
179 * hashed by id */
180 u32 tunnel_id;
181 u32 peer_tunnel_id;
182 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
183
184 char name[20]; /* for logging */
185 int debug; /* bitmask of debug message
186 * categories */
187 enum l2tp_encap_type encap;
188 struct l2tp_stats stats;
189
190 struct list_head list; /* Keep a list of all tunnels */
191 struct net *l2tp_net; /* the net we belong to */
192
193 atomic_t ref_count;
194 #ifdef CONFIG_DEBUG_FS
195 void (*show)(struct seq_file *m, void *arg);
196 #endif
197 int (*recv_payload_hook)(struct sk_buff *skb);
198 void (*old_sk_destruct)(struct sock *);
199 struct sock *sock; /* Parent socket */
200 int fd; /* Parent fd, if tunnel socket
201 * was created by userspace */
202 #if IS_ENABLED(CONFIG_IPV6)
203 bool v4mapped;
204 #endif
205
206 struct work_struct del_work;
207
208 uint8_t priv[0]; /* private data */
209 };
210
211 struct l2tp_nl_cmd_ops {
212 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
213 int (*session_delete)(struct l2tp_session *session);
214 };
215
l2tp_tunnel_priv(struct l2tp_tunnel * tunnel)216 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
217 {
218 return &tunnel->priv[0];
219 }
220
l2tp_session_priv(struct l2tp_session * session)221 static inline void *l2tp_session_priv(struct l2tp_session *session)
222 {
223 return &session->priv[0];
224 }
225
l2tp_sock_to_tunnel(struct sock * sk)226 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
227 {
228 struct l2tp_tunnel *tunnel;
229
230 if (sk == NULL)
231 return NULL;
232
233 sock_hold(sk);
234 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
235 if (tunnel == NULL) {
236 sock_put(sk);
237 goto out;
238 }
239
240 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
241
242 out:
243 return tunnel;
244 }
245
246 struct l2tp_session *l2tp_session_find(struct net *net,
247 struct l2tp_tunnel *tunnel,
248 u32 session_id);
249 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
250 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
251 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
252 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
253
254 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
255 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
256 struct l2tp_tunnel **tunnelp);
257 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
258 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
259 struct l2tp_session *l2tp_session_create(int priv_size,
260 struct l2tp_tunnel *tunnel,
261 u32 session_id, u32 peer_session_id,
262 struct l2tp_session_cfg *cfg);
263 void __l2tp_session_unhash(struct l2tp_session *session);
264 int l2tp_session_delete(struct l2tp_session *session);
265 void l2tp_session_free(struct l2tp_session *session);
266 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
267 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
268 int length, int (*payload_hook)(struct sk_buff *skb));
269 int l2tp_session_queue_purge(struct l2tp_session *session);
270 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
271 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
272
273 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
274 int hdr_len);
275
276 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
277 const struct l2tp_nl_cmd_ops *ops);
278 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
279 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
280
281 /* Session reference counts. Incremented when code obtains a reference
282 * to a session.
283 */
l2tp_session_inc_refcount_1(struct l2tp_session * session)284 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
285 {
286 atomic_inc(&session->ref_count);
287 }
288
l2tp_session_dec_refcount_1(struct l2tp_session * session)289 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
290 {
291 if (atomic_dec_and_test(&session->ref_count))
292 l2tp_session_free(session);
293 }
294
295 #ifdef L2TP_REFCNT_DEBUG
296 #define l2tp_session_inc_refcount(_s) \
297 do { \
298 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \
299 __func__, __LINE__, (_s)->name, \
300 atomic_read(&_s->ref_count)); \
301 l2tp_session_inc_refcount_1(_s); \
302 } while (0)
303 #define l2tp_session_dec_refcount(_s) \
304 do { \
305 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \
306 __func__, __LINE__, (_s)->name, \
307 atomic_read(&_s->ref_count)); \
308 l2tp_session_dec_refcount_1(_s); \
309 } while (0)
310 #else
311 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
312 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
313 #endif
314
315 #define l2tp_printk(ptr, type, func, fmt, ...) \
316 do { \
317 if (((ptr)->debug) & (type)) \
318 func(fmt, ##__VA_ARGS__); \
319 } while (0)
320
321 #define l2tp_warn(ptr, type, fmt, ...) \
322 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
323 #define l2tp_info(ptr, type, fmt, ...) \
324 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
325 #define l2tp_dbg(ptr, type, fmt, ...) \
326 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
327
328 #endif /* _L2TP_CORE_H_ */
329