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Linux kernel mirror (for testing)
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linux
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 */
27enum {
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
36struct sk_buff;
37
38struct 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
50struct l2tp_tunnel;
51
52/* Describes a session. Contains information to determine incoming
53 * packets and transmit outgoing ones.
54 */
55struct 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
85struct 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 u32 nr_max; /* max NR. Depends on tunnel */
106 u32 nr_window_size; /* NR window size */
107 u32 nr_oos; /* NR of last OOS packet */
108 int nr_oos_count; /* For OOS recovery */
109 int nr_oos_count_max;
110 struct hlist_node hlist; /* Hash list node */
111 atomic_t ref_count;
112
113 char name[32]; /* for logging */
114 char ifname[IFNAMSIZ];
115 unsigned int data_seq:2; /* data sequencing level
116 * 0 => none, 1 => IP only,
117 * 2 => all
118 */
119 unsigned int recv_seq:1; /* expect receive packets with
120 * sequence numbers? */
121 unsigned int send_seq:1; /* send packets with sequence
122 * numbers? */
123 unsigned int lns_mode:1; /* behave as LNS? LAC enables
124 * sequence numbers under
125 * control of LNS. */
126 int debug; /* bitmask of debug message
127 * categories */
128 int reorder_timeout; /* configured reorder timeout
129 * (in jiffies) */
130 int reorder_skip; /* set if skip to next nr */
131 int mtu;
132 int mru;
133 enum l2tp_pwtype pwtype;
134 struct l2tp_stats stats;
135 struct hlist_node global_hlist; /* Global hash list node */
136
137 int (*build_header)(struct l2tp_session *session, void *buf);
138 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
139 void (*session_close)(struct l2tp_session *session);
140 void (*ref)(struct l2tp_session *session);
141 void (*deref)(struct l2tp_session *session);
142#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
143 void (*show)(struct seq_file *m, void *priv);
144#endif
145 uint8_t priv[0]; /* private data */
146};
147
148/* Describes the tunnel. It contains info to track all the associated
149 * sessions so incoming packets can be sorted out
150 */
151struct l2tp_tunnel_cfg {
152 int debug; /* bitmask of debug message
153 * categories */
154 enum l2tp_encap_type encap;
155
156 /* Used only for kernel-created sockets */
157 struct in_addr local_ip;
158 struct in_addr peer_ip;
159#if IS_ENABLED(CONFIG_IPV6)
160 struct in6_addr *local_ip6;
161 struct in6_addr *peer_ip6;
162#endif
163 u16 local_udp_port;
164 u16 peer_udp_port;
165 unsigned int use_udp_checksums:1;
166};
167
168struct l2tp_tunnel {
169 int magic; /* Should be L2TP_TUNNEL_MAGIC */
170 struct rcu_head rcu;
171 rwlock_t hlist_lock; /* protect session_hlist */
172 struct hlist_head session_hlist[L2TP_HASH_SIZE];
173 /* hashed list of sessions,
174 * hashed by id */
175 u32 tunnel_id;
176 u32 peer_tunnel_id;
177 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
178
179 char name[20]; /* for logging */
180 int debug; /* bitmask of debug message
181 * categories */
182 enum l2tp_encap_type encap;
183 struct l2tp_stats stats;
184
185 struct list_head list; /* Keep a list of all tunnels */
186 struct net *l2tp_net; /* the net we belong to */
187
188 atomic_t ref_count;
189#ifdef CONFIG_DEBUG_FS
190 void (*show)(struct seq_file *m, void *arg);
191#endif
192 int (*recv_payload_hook)(struct sk_buff *skb);
193 void (*old_sk_destruct)(struct sock *);
194 struct sock *sock; /* Parent socket */
195 int fd; /* Parent fd, if tunnel socket
196 * was created by userspace */
197#if IS_ENABLED(CONFIG_IPV6)
198 bool v4mapped;
199#endif
200
201 struct work_struct del_work;
202
203 uint8_t priv[0]; /* private data */
204};
205
206struct l2tp_nl_cmd_ops {
207 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
208 int (*session_delete)(struct l2tp_session *session);
209};
210
211static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
212{
213 return &tunnel->priv[0];
214}
215
216static inline void *l2tp_session_priv(struct l2tp_session *session)
217{
218 return &session->priv[0];
219}
220
221static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
222{
223 struct l2tp_tunnel *tunnel;
224
225 if (sk == NULL)
226 return NULL;
227
228 sock_hold(sk);
229 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
230 if (tunnel == NULL) {
231 sock_put(sk);
232 goto out;
233 }
234
235 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
236
237out:
238 return tunnel;
239}
240
241struct l2tp_session *l2tp_session_find(struct net *net,
242 struct l2tp_tunnel *tunnel,
243 u32 session_id);
244struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
245struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
246struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
247struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
248
249int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
250 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
251 struct l2tp_tunnel **tunnelp);
252void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
253int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
254struct l2tp_session *l2tp_session_create(int priv_size,
255 struct l2tp_tunnel *tunnel,
256 u32 session_id, u32 peer_session_id,
257 struct l2tp_session_cfg *cfg);
258void __l2tp_session_unhash(struct l2tp_session *session);
259int l2tp_session_delete(struct l2tp_session *session);
260void l2tp_session_free(struct l2tp_session *session);
261void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
262 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
263 int length, int (*payload_hook)(struct sk_buff *skb));
264int l2tp_session_queue_purge(struct l2tp_session *session);
265int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
266
267int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
268 int hdr_len);
269
270int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
271 const struct l2tp_nl_cmd_ops *ops);
272void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
273
274/* Session reference counts. Incremented when code obtains a reference
275 * to a session.
276 */
277static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
278{
279 atomic_inc(&session->ref_count);
280}
281
282static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
283{
284 if (atomic_dec_and_test(&session->ref_count))
285 l2tp_session_free(session);
286}
287
288#ifdef L2TP_REFCNT_DEBUG
289#define l2tp_session_inc_refcount(_s) \
290do { \
291 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \
292 __func__, __LINE__, (_s)->name, \
293 atomic_read(&_s->ref_count)); \
294 l2tp_session_inc_refcount_1(_s); \
295} while (0)
296#define l2tp_session_dec_refcount(_s) \
297do { \
298 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \
299 __func__, __LINE__, (_s)->name, \
300 atomic_read(&_s->ref_count)); \
301 l2tp_session_dec_refcount_1(_s); \
302} while (0)
303#else
304#define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
305#define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
306#endif
307
308#define l2tp_printk(ptr, type, func, fmt, ...) \
309do { \
310 if (((ptr)->debug) & (type)) \
311 func(fmt, ##__VA_ARGS__); \
312} while (0)
313
314#define l2tp_warn(ptr, type, fmt, ...) \
315 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
316#define l2tp_info(ptr, type, fmt, ...) \
317 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
318#define l2tp_dbg(ptr, type, fmt, ...) \
319 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
320
321#endif /* _L2TP_CORE_H_ */