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 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
137 void (*show)(struct seq_file *m, void *priv);
138 #endif
139 uint8_t priv[0]; /* private data */
140 };
141
142 /* Describes the tunnel. It contains info to track all the associated
143 * sessions so incoming packets can be sorted out
144 */
145 struct l2tp_tunnel_cfg {
146 int debug; /* bitmask of debug message
147 * categories */
148 enum l2tp_encap_type encap;
149
150 /* Used only for kernel-created sockets */
151 struct in_addr local_ip;
152 struct in_addr peer_ip;
153 u16 local_udp_port;
154 u16 peer_udp_port;
155 unsigned int use_udp_checksums:1;
156 };
157
158 struct l2tp_tunnel {
159 int magic; /* Should be L2TP_TUNNEL_MAGIC */
160 struct rcu_head rcu;
161 rwlock_t hlist_lock; /* protect session_hlist */
162 struct hlist_head session_hlist[L2TP_HASH_SIZE];
163 /* hashed list of sessions,
164 * hashed by id */
165 u32 tunnel_id;
166 u32 peer_tunnel_id;
167 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
168
169 char name[20]; /* for logging */
170 int debug; /* bitmask of debug message
171 * categories */
172 enum l2tp_encap_type encap;
173 struct l2tp_stats stats;
174
175 struct list_head list; /* Keep a list of all tunnels */
176 struct net *l2tp_net; /* the net we belong to */
177
178 atomic_t ref_count;
179 #ifdef CONFIG_DEBUG_FS
180 void (*show)(struct seq_file *m, void *arg);
181 #endif
182 int (*recv_payload_hook)(struct sk_buff *skb);
183 void (*old_sk_destruct)(struct sock *);
184 struct sock *sock; /* Parent socket */
185 int fd;
186
187 uint8_t priv[0]; /* private data */
188 };
189
190 struct l2tp_nl_cmd_ops {
191 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
192 int (*session_delete)(struct l2tp_session *session);
193 };
194
l2tp_tunnel_priv(struct l2tp_tunnel * tunnel)195 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
196 {
197 return &tunnel->priv[0];
198 }
199
l2tp_session_priv(struct l2tp_session * session)200 static inline void *l2tp_session_priv(struct l2tp_session *session)
201 {
202 return &session->priv[0];
203 }
204
l2tp_sock_to_tunnel(struct sock * sk)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_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
228 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
229 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
230
231 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);
232 extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
233 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);
234 extern int l2tp_session_delete(struct l2tp_session *session);
235 extern void l2tp_session_free(struct l2tp_session *session);
236 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));
237 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
238
239 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
240
241 extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
242 extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
243
244 /* Session reference counts. Incremented when code obtains a reference
245 * to a session.
246 */
l2tp_session_inc_refcount_1(struct l2tp_session * session)247 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
248 {
249 atomic_inc(&session->ref_count);
250 }
251
l2tp_session_dec_refcount_1(struct l2tp_session * session)252 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
253 {
254 if (atomic_dec_and_test(&session->ref_count))
255 l2tp_session_free(session);
256 }
257
258 #ifdef L2TP_REFCNT_DEBUG
259 #define l2tp_session_inc_refcount(_s) do { \
260 printk(KERN_DEBUG "l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
261 l2tp_session_inc_refcount_1(_s); \
262 } while (0)
263 #define l2tp_session_dec_refcount(_s) do { \
264 printk(KERN_DEBUG "l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
265 l2tp_session_dec_refcount_1(_s); \
266 } while (0)
267 #else
268 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
269 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
270 #endif
271
272 #endif /* _L2TP_CORE_H_ */
273