l2tp: Add L2TPv3 IP encapsulation (no UDP) support
[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 enum l2tp_pwtype {
37         L2TP_PWTYPE_NONE = 0x0000,
38         L2TP_PWTYPE_ETH_VLAN = 0x0004,
39         L2TP_PWTYPE_ETH = 0x0005,
40         L2TP_PWTYPE_PPP = 0x0007,
41         L2TP_PWTYPE_PPP_AC = 0x0008,
42         L2TP_PWTYPE_IP = 0x000b,
43         __L2TP_PWTYPE_MAX
44 };
45
46 enum l2tp_l2spec_type {
47         L2TP_L2SPECTYPE_NONE,
48         L2TP_L2SPECTYPE_DEFAULT,
49 };
50
51 enum l2tp_encap_type {
52         L2TP_ENCAPTYPE_UDP,
53         L2TP_ENCAPTYPE_IP,
54 };
55
56 struct sk_buff;
57
58 struct l2tp_stats {
59         u64                     tx_packets;
60         u64                     tx_bytes;
61         u64                     tx_errors;
62         u64                     rx_packets;
63         u64                     rx_bytes;
64         u64                     rx_seq_discards;
65         u64                     rx_oos_packets;
66         u64                     rx_errors;
67         u64                     rx_cookie_discards;
68 };
69
70 struct l2tp_tunnel;
71
72 /* Describes a session. Contains information to determine incoming
73  * packets and transmit outgoing ones.
74  */
75 struct l2tp_session_cfg {
76         enum l2tp_pwtype        pw_type;
77         unsigned                data_seq:2;     /* data sequencing level
78                                                  * 0 => none, 1 => IP only,
79                                                  * 2 => all
80                                                  */
81         unsigned                recv_seq:1;     /* expect receive packets with
82                                                  * sequence numbers? */
83         unsigned                send_seq:1;     /* send packets with sequence
84                                                  * numbers? */
85         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
86                                                  * sequence numbers under
87                                                  * control of LNS. */
88         int                     debug;          /* bitmask of debug message
89                                                  * categories */
90         u16                     offset;         /* offset to payload */
91         u16                     l2specific_len; /* Layer 2 specific length */
92         u16                     l2specific_type; /* Layer 2 specific type */
93         u8                      cookie[8];      /* optional cookie */
94         int                     cookie_len;     /* 0, 4 or 8 bytes */
95         u8                      peer_cookie[8]; /* peer's cookie */
96         int                     peer_cookie_len; /* 0, 4 or 8 bytes */
97         int                     reorder_timeout; /* configured reorder timeout
98                                                   * (in jiffies) */
99         int                     mtu;
100         int                     mru;
101 };
102
103 struct l2tp_session {
104         int                     magic;          /* should be
105                                                  * L2TP_SESSION_MAGIC */
106
107         struct l2tp_tunnel      *tunnel;        /* back pointer to tunnel
108                                                  * context */
109         u32                     session_id;
110         u32                     peer_session_id;
111         u8                      cookie[8];
112         int                     cookie_len;
113         u8                      peer_cookie[8];
114         int                     peer_cookie_len;
115         u16                     offset;         /* offset from end of L2TP header
116                                                    to beginning of data */
117         u16                     l2specific_len;
118         u16                     l2specific_type;
119         u16                     hdr_len;
120         u32                     nr;             /* session NR state (receive) */
121         u32                     ns;             /* session NR state (send) */
122         struct sk_buff_head     reorder_q;      /* receive reorder queue */
123         struct hlist_node       hlist;          /* Hash list node */
124         atomic_t                ref_count;
125
126         char                    name[32];       /* for logging */
127         unsigned                data_seq:2;     /* data sequencing level
128                                                  * 0 => none, 1 => IP only,
129                                                  * 2 => all
130                                                  */
131         unsigned                recv_seq:1;     /* expect receive packets with
132                                                  * sequence numbers? */
133         unsigned                send_seq:1;     /* send packets with sequence
134                                                  * numbers? */
135         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
136                                                  * sequence numbers under
137                                                  * control of LNS. */
138         int                     debug;          /* bitmask of debug message
139                                                  * categories */
140         int                     reorder_timeout; /* configured reorder timeout
141                                                   * (in jiffies) */
142         int                     mtu;
143         int                     mru;
144         enum l2tp_pwtype        pwtype;
145         struct l2tp_stats       stats;
146         struct hlist_node       global_hlist;   /* Global hash list node */
147
148         int (*build_header)(struct l2tp_session *session, void *buf);
149         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
150         void (*session_close)(struct l2tp_session *session);
151         void (*ref)(struct l2tp_session *session);
152         void (*deref)(struct l2tp_session *session);
153
154         uint8_t                 priv[0];        /* private data */
155 };
156
157 /* Describes the tunnel. It contains info to track all the associated
158  * sessions so incoming packets can be sorted out
159  */
160 struct l2tp_tunnel_cfg {
161         int                     debug;          /* bitmask of debug message
162                                                  * categories */
163         enum l2tp_encap_type    encap;
164 };
165
166 struct l2tp_tunnel {
167         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
168         rwlock_t                hlist_lock;     /* protect session_hlist */
169         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
170                                                 /* hashed list of sessions,
171                                                  * hashed by id */
172         u32                     tunnel_id;
173         u32                     peer_tunnel_id;
174         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
175
176         char                    name[20];       /* for logging */
177         int                     debug;          /* bitmask of debug message
178                                                  * categories */
179         enum l2tp_encap_type    encap;
180         struct l2tp_stats       stats;
181
182         struct list_head        list;           /* Keep a list of all tunnels */
183         struct net              *l2tp_net;      /* the net we belong to */
184
185         atomic_t                ref_count;
186
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;
191
192         uint8_t                 priv[0];        /* private data */
193 };
194
195 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
196 {
197         return &tunnel->priv[0];
198 }
199
200 static inline void *l2tp_session_priv(struct l2tp_session *session)
201 {
202         return &session->priv[0];
203 }
204
205 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
206 {
207         struct l2tp_tunnel *tunnel;
208
209         if (sk == NULL)
210                 return NULL;
211
212         sock_hold(sk);
213         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
214         if (tunnel == NULL) {
215                 sock_put(sk);
216                 goto out;
217         }
218
219         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
220
221 out:
222         return tunnel;
223 }
224
225 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
226 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
227 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
228 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
229
230 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);
231 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);
232 extern void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
233 extern void l2tp_session_free(struct l2tp_session *session);
234 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));
235 extern int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, int (*payload_hook)(struct sk_buff *skb));
236 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
237
238 extern int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len);
239 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
240 extern void l2tp_tunnel_destruct(struct sock *sk);
241 extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
242 extern void l2tp_session_set_header_len(struct l2tp_session *session, int version);
243
244 /* Tunnel reference counts. Incremented per session that is added to
245  * the tunnel.
246  */
247 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
248 {
249         atomic_inc(&tunnel->ref_count);
250 }
251
252 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
253 {
254         if (atomic_dec_and_test(&tunnel->ref_count))
255                 l2tp_tunnel_free(tunnel);
256 }
257 #ifdef L2TP_REFCNT_DEBUG
258 #define l2tp_tunnel_inc_refcount(_t) do { \
259                 printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
260                 l2tp_tunnel_inc_refcount_1(_t);                         \
261         } while (0)
262 #define l2tp_tunnel_dec_refcount(_t) do { \
263                 printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
264                 l2tp_tunnel_dec_refcount_1(_t);                         \
265         } while (0)
266 #else
267 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
268 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
269 #endif
270
271 /* Session reference counts. Incremented when code obtains a reference
272  * to a session.
273  */
274 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
275 {
276         atomic_inc(&session->ref_count);
277 }
278
279 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
280 {
281         if (atomic_dec_and_test(&session->ref_count))
282                 l2tp_session_free(session);
283 }
284
285 #ifdef L2TP_REFCNT_DEBUG
286 #define l2tp_session_inc_refcount(_s) do { \
287                 printk(KERN_DEBUG "l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
288                 l2tp_session_inc_refcount_1(_s);                                \
289         } while (0)
290 #define l2tp_session_dec_refcount(_s) do { \
291                 printk(KERN_DEBUG "l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
292                 l2tp_session_dec_refcount_1(_s);                                \
293         } while (0)
294 #else
295 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
296 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
297 #endif
298
299 #endif /* _L2TP_CORE_H_ */