8eb8f1d47f3ac2d6ce32ae287e120a93aa931b40
[linux-3.10.git] / net / l2tp / l2tp_core.h
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         u64                     tx_packets;
40         u64                     tx_bytes;
41         u64                     tx_errors;
42         u64                     rx_packets;
43         u64                     rx_bytes;
44         u64                     rx_seq_discards;
45         u64                     rx_oos_packets;
46         u64                     rx_errors;
47         u64                     rx_cookie_discards;
48         struct u64_stats_sync   syncp;
49 };
50
51 struct l2tp_tunnel;
52
53 /* Describes a session. Contains information to determine incoming
54  * packets and transmit outgoing ones.
55  */
56 struct l2tp_session_cfg {
57         enum l2tp_pwtype        pw_type;
58         unsigned int            data_seq:2;     /* data sequencing level
59                                                  * 0 => none, 1 => IP only,
60                                                  * 2 => all
61                                                  */
62         unsigned int            recv_seq:1;     /* expect receive packets with
63                                                  * sequence numbers? */
64         unsigned int            send_seq:1;     /* send packets with sequence
65                                                  * numbers? */
66         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
67                                                  * sequence numbers under
68                                                  * control of LNS. */
69         int                     debug;          /* bitmask of debug message
70                                                  * categories */
71         u16                     vlan_id;        /* VLAN pseudowire only */
72         u16                     offset;         /* offset to payload */
73         u16                     l2specific_len; /* Layer 2 specific length */
74         u16                     l2specific_type; /* Layer 2 specific type */
75         u8                      cookie[8];      /* optional cookie */
76         int                     cookie_len;     /* 0, 4 or 8 bytes */
77         u8                      peer_cookie[8]; /* peer's cookie */
78         int                     peer_cookie_len; /* 0, 4 or 8 bytes */
79         int                     reorder_timeout; /* configured reorder timeout
80                                                   * (in jiffies) */
81         int                     mtu;
82         int                     mru;
83         char                    *ifname;
84 };
85
86 struct l2tp_session {
87         int                     magic;          /* should be
88                                                  * L2TP_SESSION_MAGIC */
89
90         struct l2tp_tunnel      *tunnel;        /* back pointer to tunnel
91                                                  * context */
92         u32                     session_id;
93         u32                     peer_session_id;
94         u8                      cookie[8];
95         int                     cookie_len;
96         u8                      peer_cookie[8];
97         int                     peer_cookie_len;
98         u16                     offset;         /* offset from end of L2TP header
99                                                    to beginning of data */
100         u16                     l2specific_len;
101         u16                     l2specific_type;
102         u16                     hdr_len;
103         u32                     nr;             /* session NR state (receive) */
104         u32                     ns;             /* session NR state (send) */
105         struct sk_buff_head     reorder_q;      /* receive reorder queue */
106         struct hlist_node       hlist;          /* Hash list node */
107         atomic_t                ref_count;
108
109         char                    name[32];       /* for logging */
110         char                    ifname[IFNAMSIZ];
111         unsigned int            data_seq:2;     /* data sequencing level
112                                                  * 0 => none, 1 => IP only,
113                                                  * 2 => all
114                                                  */
115         unsigned int            recv_seq:1;     /* expect receive packets with
116                                                  * sequence numbers? */
117         unsigned int            send_seq:1;     /* send packets with sequence
118                                                  * numbers? */
119         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
120                                                  * sequence numbers under
121                                                  * control of LNS. */
122         int                     debug;          /* bitmask of debug message
123                                                  * categories */
124         int                     reorder_timeout; /* configured reorder timeout
125                                                   * (in jiffies) */
126         int                     reorder_skip;   /* set if skip to next nr */
127         int                     mtu;
128         int                     mru;
129         enum l2tp_pwtype        pwtype;
130         struct l2tp_stats       stats;
131         struct hlist_node       global_hlist;   /* Global hash list node */
132
133         int (*build_header)(struct l2tp_session *session, void *buf);
134         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
135         void (*session_close)(struct l2tp_session *session);
136         void (*ref)(struct l2tp_session *session);
137         void (*deref)(struct l2tp_session *session);
138 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
139         void (*show)(struct seq_file *m, void *priv);
140 #endif
141         uint8_t                 priv[0];        /* private data */
142 };
143
144 /* Describes the tunnel. It contains info to track all the associated
145  * sessions so incoming packets can be sorted out
146  */
147 struct l2tp_tunnel_cfg {
148         int                     debug;          /* bitmask of debug message
149                                                  * categories */
150         enum l2tp_encap_type    encap;
151
152         /* Used only for kernel-created sockets */
153         struct in_addr          local_ip;
154         struct in_addr          peer_ip;
155 #if IS_ENABLED(CONFIG_IPV6)
156         struct in6_addr         *local_ip6;
157         struct in6_addr         *peer_ip6;
158 #endif
159         u16                     local_udp_port;
160         u16                     peer_udp_port;
161         unsigned int            use_udp_checksums:1;
162 };
163
164 struct l2tp_tunnel {
165         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
166         struct rcu_head rcu;
167         rwlock_t                hlist_lock;     /* protect session_hlist */
168         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
169                                                 /* hashed list of sessions,
170                                                  * hashed by id */
171         u32                     tunnel_id;
172         u32                     peer_tunnel_id;
173         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
174
175         char                    name[20];       /* for logging */
176         int                     debug;          /* bitmask of debug message
177                                                  * categories */
178         enum l2tp_encap_type    encap;
179         struct l2tp_stats       stats;
180
181         struct list_head        list;           /* Keep a list of all tunnels */
182         struct net              *l2tp_net;      /* the net we belong to */
183
184         atomic_t                ref_count;
185 #ifdef CONFIG_DEBUG_FS
186         void (*show)(struct seq_file *m, void *arg);
187 #endif
188         int (*recv_payload_hook)(struct sk_buff *skb);
189         void (*old_sk_destruct)(struct sock *);
190         struct sock             *sock;          /* Parent socket */
191         int                     fd;             /* Parent fd, if tunnel socket
192                                                  * was created by userspace */
193
194         struct work_struct      del_work;
195
196         uint8_t                 priv[0];        /* private data */
197 };
198
199 struct l2tp_nl_cmd_ops {
200         int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
201         int (*session_delete)(struct l2tp_session *session);
202 };
203
204 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
205 {
206         return &tunnel->priv[0];
207 }
208
209 static inline void *l2tp_session_priv(struct l2tp_session *session)
210 {
211         return &session->priv[0];
212 }
213
214 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
215 {
216         struct l2tp_tunnel *tunnel;
217
218         if (sk == NULL)
219                 return NULL;
220
221         sock_hold(sk);
222         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
223         if (tunnel == NULL) {
224                 sock_put(sk);
225                 goto out;
226         }
227
228         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
229
230 out:
231         return tunnel;
232 }
233
234 extern struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel);
235 extern void l2tp_tunnel_sock_put(struct sock *sk);
236 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
237 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
238 extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
239 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
240 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
241
242 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);
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 int l2tp_session_delete(struct l2tp_session *session);
246 extern void l2tp_session_free(struct l2tp_session *session);
247 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));
248 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
249
250 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
251
252 extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
253 extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
254
255 /* Session reference counts. Incremented when code obtains a reference
256  * to a session.
257  */
258 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
259 {
260         atomic_inc(&session->ref_count);
261 }
262
263 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
264 {
265         if (atomic_dec_and_test(&session->ref_count))
266                 l2tp_session_free(session);
267 }
268
269 #ifdef L2TP_REFCNT_DEBUG
270 #define l2tp_session_inc_refcount(_s)                                   \
271 do {                                                                    \
272         pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",       \
273                  __func__, __LINE__, (_s)->name,                        \
274                  atomic_read(&_s->ref_count));                          \
275         l2tp_session_inc_refcount_1(_s);                                \
276 } while (0)
277 #define l2tp_session_dec_refcount(_s)                                   \
278 do {                                                                    \
279         pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",       \
280                  __func__, __LINE__, (_s)->name,                        \
281                  atomic_read(&_s->ref_count));                          \
282         l2tp_session_dec_refcount_1(_s);                                \
283 } while (0)
284 #else
285 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
286 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
287 #endif
288
289 #define l2tp_printk(ptr, type, func, fmt, ...)                          \
290 do {                                                                    \
291         if (((ptr)->debug) & (type))                                    \
292                 func(fmt, ##__VA_ARGS__);                               \
293 } while (0)
294
295 #define l2tp_warn(ptr, type, fmt, ...)                                  \
296         l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
297 #define l2tp_info(ptr, type, fmt, ...)                                  \
298         l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
299 #define l2tp_dbg(ptr, type, fmt, ...)                                   \
300         l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
301
302 #endif /* _L2TP_CORE_H_ */