l2tp: Add netlink control API for L2TP
[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 };
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                data_seq:2;     /* data sequencing level
58                                                  * 0 => none, 1 => IP only,
59                                                  * 2 => all
60                                                  */
61         unsigned                recv_seq:1;     /* expect receive packets with
62                                                  * sequence numbers? */
63         unsigned                send_seq:1;     /* send packets with sequence
64                                                  * numbers? */
65         unsigned                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                data_seq:2;     /* data sequencing level
111                                                  * 0 => none, 1 => IP only,
112                                                  * 2 => all
113                                                  */
114         unsigned                recv_seq:1;     /* expect receive packets with
115                                                  * sequence numbers? */
116         unsigned                send_seq:1;     /* send packets with sequence
117                                                  * numbers? */
118         unsigned                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                     mtu;
126         int                     mru;
127         enum l2tp_pwtype        pwtype;
128         struct l2tp_stats       stats;
129         struct hlist_node       global_hlist;   /* Global hash list node */
130
131         int (*build_header)(struct l2tp_session *session, void *buf);
132         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
133         void (*session_close)(struct l2tp_session *session);
134         void (*ref)(struct l2tp_session *session);
135         void (*deref)(struct l2tp_session *session);
136
137         uint8_t                 priv[0];        /* private data */
138 };
139
140 /* Describes the tunnel. It contains info to track all the associated
141  * sessions so incoming packets can be sorted out
142  */
143 struct l2tp_tunnel_cfg {
144         int                     debug;          /* bitmask of debug message
145                                                  * categories */
146         enum l2tp_encap_type    encap;
147 };
148
149 struct l2tp_tunnel {
150         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
151         rwlock_t                hlist_lock;     /* protect session_hlist */
152         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
153                                                 /* hashed list of sessions,
154                                                  * hashed by id */
155         u32                     tunnel_id;
156         u32                     peer_tunnel_id;
157         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
158
159         char                    name[20];       /* for logging */
160         int                     debug;          /* bitmask of debug message
161                                                  * categories */
162         enum l2tp_encap_type    encap;
163         struct l2tp_stats       stats;
164
165         struct list_head        list;           /* Keep a list of all tunnels */
166         struct net              *l2tp_net;      /* the net we belong to */
167
168         atomic_t                ref_count;
169
170         int (*recv_payload_hook)(struct sk_buff *skb);
171         void (*old_sk_destruct)(struct sock *);
172         struct sock             *sock;          /* Parent socket */
173         int                     fd;
174
175         uint8_t                 priv[0];        /* private data */
176 };
177
178 struct l2tp_nl_cmd_ops {
179         int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
180         int (*session_delete)(struct l2tp_session *session);
181 };
182
183 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
184 {
185         return &tunnel->priv[0];
186 }
187
188 static inline void *l2tp_session_priv(struct l2tp_session *session)
189 {
190         return &session->priv[0];
191 }
192
193 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
194 {
195         struct l2tp_tunnel *tunnel;
196
197         if (sk == NULL)
198                 return NULL;
199
200         sock_hold(sk);
201         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
202         if (tunnel == NULL) {
203                 sock_put(sk);
204                 goto out;
205         }
206
207         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
208
209 out:
210         return tunnel;
211 }
212
213 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
214 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
215 extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
216 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
217 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
218
219 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);
220 extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
221 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);
222 extern int l2tp_session_delete(struct l2tp_session *session);
223 extern void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
224 extern void l2tp_session_free(struct l2tp_session *session);
225 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));
226 extern int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, int (*payload_hook)(struct sk_buff *skb));
227 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
228
229 extern int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len);
230 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
231 extern void l2tp_tunnel_destruct(struct sock *sk);
232 extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
233 extern void l2tp_session_set_header_len(struct l2tp_session *session, int version);
234
235 extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
236 extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
237
238 /* Tunnel reference counts. Incremented per session that is added to
239  * the tunnel.
240  */
241 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
242 {
243         atomic_inc(&tunnel->ref_count);
244 }
245
246 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
247 {
248         if (atomic_dec_and_test(&tunnel->ref_count))
249                 l2tp_tunnel_free(tunnel);
250 }
251 #ifdef L2TP_REFCNT_DEBUG
252 #define l2tp_tunnel_inc_refcount(_t) do { \
253                 printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
254                 l2tp_tunnel_inc_refcount_1(_t);                         \
255         } while (0)
256 #define l2tp_tunnel_dec_refcount(_t) do { \
257                 printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
258                 l2tp_tunnel_dec_refcount_1(_t);                         \
259         } while (0)
260 #else
261 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
262 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
263 #endif
264
265 /* Session reference counts. Incremented when code obtains a reference
266  * to a session.
267  */
268 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
269 {
270         atomic_inc(&session->ref_count);
271 }
272
273 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
274 {
275         if (atomic_dec_and_test(&session->ref_count))
276                 l2tp_session_free(session);
277 }
278
279 #ifdef L2TP_REFCNT_DEBUG
280 #define l2tp_session_inc_refcount(_s) do { \
281                 printk(KERN_DEBUG "l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
282                 l2tp_session_inc_refcount_1(_s);                                \
283         } while (0)
284 #define l2tp_session_dec_refcount(_s) do { \
285                 printk(KERN_DEBUG "l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
286                 l2tp_session_dec_refcount_1(_s);                                \
287         } while (0)
288 #else
289 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
290 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
291 #endif
292
293 #endif /* _L2TP_CORE_H_ */