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 struct hlist_node hlist; /* Hash list node */
106 atomic_t ref_count;
107
108 char name[32]; /* for logging */
109 char ifname[IFNAMSIZ];
110 unsigned int data_seq:2; /* data sequencing level
111 * 0 => none, 1 => IP only,
112 * 2 => all
113 */
114 unsigned int recv_seq:1; /* expect receive packets with
115 * sequence numbers? */
116 unsigned int send_seq:1; /* send packets with sequence
117 * numbers? */
118 unsigned int lns_mode:1; /* behave as LNS? LAC enables
119 * sequence numbers under
120 * control of LNS. */
121 int debug; /* bitmask of debug message
122 * categories */
123 int reorder_timeout; /* configured reorder timeout
124 * (in jiffies) */
125 int reorder_skip; /* set if skip to next nr */
126 int mtu;
127 int mru;
128 enum l2tp_pwtype pwtype;
129 struct l2tp_stats stats;
130 struct hlist_node global_hlist; /* Global hash list node */
131
132 int (*build_header)(struct l2tp_session *session, void *buf);
133 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
134 void (*session_close)(struct l2tp_session *session);
135 void (*ref)(struct l2tp_session *session);
136 void (*deref)(struct l2tp_session *session);
137 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
138 void (*show)(struct seq_file *m, void *priv);
139 #endif
140 uint8_t priv[0]; /* private data */
141 };
142
143 /* Describes the tunnel. It contains info to track all the associated
144 * sessions so incoming packets can be sorted out
145 */
146 struct l2tp_tunnel_cfg {
147 int debug; /* bitmask of debug message
148 * categories */
149 enum l2tp_encap_type encap;
150
151 /* Used only for kernel-created sockets */
152 struct in_addr local_ip;
153 struct in_addr peer_ip;
154 #if IS_ENABLED(CONFIG_IPV6)
155 struct in6_addr *local_ip6;
156 struct in6_addr *peer_ip6;
157 #endif
158 u16 local_udp_port;
159 u16 peer_udp_port;
160 unsigned int use_udp_checksums:1;
161 };
162
163 struct l2tp_tunnel {
164 int magic; /* Should be L2TP_TUNNEL_MAGIC */
165 struct rcu_head rcu;
166 rwlock_t hlist_lock; /* protect session_hlist */
167 struct hlist_head session_hlist[L2TP_HASH_SIZE];
168 /* hashed list of sessions,
169 * hashed by id */
170 u32 tunnel_id;
171 u32 peer_tunnel_id;
172 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
173
174 char name[20]; /* for logging */
175 int debug; /* bitmask of debug message
176 * categories */
177 enum l2tp_encap_type encap;
178 struct l2tp_stats stats;
179
180 struct list_head list; /* Keep a list of all tunnels */
181 struct net *l2tp_net; /* the net we belong to */
182
183 atomic_t ref_count;
184 #ifdef CONFIG_DEBUG_FS
185 void (*show)(struct seq_file *m, void *arg);
186 #endif
187 int (*recv_payload_hook)(struct sk_buff *skb);
188 void (*old_sk_destruct)(struct sock *);
189 struct sock *sock; /* Parent socket */
190 int fd; /* Parent fd, if tunnel socket
191 * was created by userspace */
192
193 struct work_struct del_work;
194
195 uint8_t priv[0]; /* private data */
196 };
197
198 struct l2tp_nl_cmd_ops {
199 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
200 int (*session_delete)(struct l2tp_session *session);
201 };
202
l2tp_tunnel_priv(struct l2tp_tunnel * tunnel)203 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
204 {
205 return &tunnel->priv[0];
206 }
207
l2tp_session_priv(struct l2tp_session * session)208 static inline void *l2tp_session_priv(struct l2tp_session *session)
209 {
210 return &session->priv[0];
211 }
212
l2tp_sock_to_tunnel(struct sock * sk)213 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
214 {
215 struct l2tp_tunnel *tunnel;
216
217 if (sk == NULL)
218 return NULL;
219
220 sock_hold(sk);
221 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
222 if (tunnel == NULL) {
223 sock_put(sk);
224 goto out;
225 }
226
227 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
228
229 out:
230 return tunnel;
231 }
232
233 extern struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel);
234 extern void l2tp_tunnel_sock_put(struct sock *sk);
235 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
236 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
237 extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
238 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
239 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
240
241 extern 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);
242 extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
243 extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
244 extern 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);
245 extern void __l2tp_session_unhash(struct l2tp_session *session);
246 extern int l2tp_session_delete(struct l2tp_session *session);
247 extern void l2tp_session_free(struct l2tp_session *session);
248 extern 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));
249 extern int l2tp_session_queue_purge(struct l2tp_session *session);
250 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
251
252 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
253
254 extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
255 extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
256
257 /* Session reference counts. Incremented when code obtains a reference
258 * to a session.
259 */
l2tp_session_inc_refcount_1(struct l2tp_session * session)260 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
261 {
262 atomic_inc(&session->ref_count);
263 }
264
l2tp_session_dec_refcount_1(struct l2tp_session * session)265 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
266 {
267 if (atomic_dec_and_test(&session->ref_count))
268 l2tp_session_free(session);
269 }
270
271 #ifdef L2TP_REFCNT_DEBUG
272 #define l2tp_session_inc_refcount(_s) \
273 do { \
274 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \
275 __func__, __LINE__, (_s)->name, \
276 atomic_read(&_s->ref_count)); \
277 l2tp_session_inc_refcount_1(_s); \
278 } while (0)
279 #define l2tp_session_dec_refcount(_s) \
280 do { \
281 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \
282 __func__, __LINE__, (_s)->name, \
283 atomic_read(&_s->ref_count)); \
284 l2tp_session_dec_refcount_1(_s); \
285 } while (0)
286 #else
287 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
288 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
289 #endif
290
291 #define l2tp_printk(ptr, type, func, fmt, ...) \
292 do { \
293 if (((ptr)->debug) & (type)) \
294 func(fmt, ##__VA_ARGS__); \
295 } while (0)
296
297 #define l2tp_warn(ptr, type, fmt, ...) \
298 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
299 #define l2tp_info(ptr, type, fmt, ...) \
300 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
301 #define l2tp_dbg(ptr, type, fmt, ...) \
302 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
303
304 #endif /* _L2TP_CORE_H_ */
305