l2tp: fix race in duplicate tunnel detection
[linux-2.6-block.git] / net / l2tp / l2tp_core.h
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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 */
fbea9e07 10#include <linux/refcount.h>
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11
12#ifndef _L2TP_CORE_H_
13#define _L2TP_CORE_H_
14
15/* Just some random numbers */
16#define L2TP_TUNNEL_MAGIC 0x42114DDA
17#define L2TP_SESSION_MAGIC 0x0C04EB7D
18
f7faffa3 19/* Per tunnel, session hash table size */
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20#define L2TP_HASH_BITS 4
21#define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS)
22
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23/* System-wide, session hash table size */
24#define L2TP_HASH_BITS_2 8
25#define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2)
26
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27struct sk_buff;
28
29struct l2tp_stats {
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30 atomic_long_t tx_packets;
31 atomic_long_t tx_bytes;
32 atomic_long_t tx_errors;
33 atomic_long_t rx_packets;
34 atomic_long_t rx_bytes;
35 atomic_long_t rx_seq_discards;
36 atomic_long_t rx_oos_packets;
37 atomic_long_t rx_errors;
38 atomic_long_t rx_cookie_discards;
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39};
40
41struct l2tp_tunnel;
42
43/* Describes a session. Contains information to determine incoming
44 * packets and transmit outgoing ones.
45 */
46struct l2tp_session_cfg {
f7faffa3 47 enum l2tp_pwtype pw_type;
95c96174 48 unsigned int data_seq:2; /* data sequencing level
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49 * 0 => none, 1 => IP only,
50 * 2 => all
51 */
95c96174 52 unsigned int recv_seq:1; /* expect receive packets with
fd558d18 53 * sequence numbers? */
95c96174 54 unsigned int send_seq:1; /* send packets with sequence
fd558d18 55 * numbers? */
95c96174 56 unsigned int lns_mode:1; /* behave as LNS? LAC enables
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57 * sequence numbers under
58 * control of LNS. */
59 int debug; /* bitmask of debug message
60 * categories */
309795f4 61 u16 vlan_id; /* VLAN pseudowire only */
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62 u16 l2specific_type; /* Layer 2 specific type */
63 u8 cookie[8]; /* optional cookie */
64 int cookie_len; /* 0, 4 or 8 bytes */
65 u8 peer_cookie[8]; /* peer's cookie */
66 int peer_cookie_len; /* 0, 4 or 8 bytes */
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67 int reorder_timeout; /* configured reorder timeout
68 * (in jiffies) */
69 int mtu;
70 int mru;
309795f4 71 char *ifname;
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72};
73
74struct l2tp_session {
75 int magic; /* should be
76 * L2TP_SESSION_MAGIC */
b228a940 77 long dead;
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78
79 struct l2tp_tunnel *tunnel; /* back pointer to tunnel
80 * context */
81 u32 session_id;
82 u32 peer_session_id;
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83 u8 cookie[8];
84 int cookie_len;
85 u8 peer_cookie[8];
86 int peer_cookie_len;
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87 u16 l2specific_type;
88 u16 hdr_len;
89 u32 nr; /* session NR state (receive) */
90 u32 ns; /* session NR state (send) */
fd558d18 91 struct sk_buff_head reorder_q; /* receive reorder queue */
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92 u32 nr_max; /* max NR. Depends on tunnel */
93 u32 nr_window_size; /* NR window size */
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94 u32 nr_oos; /* NR of last OOS packet */
95 int nr_oos_count; /* For OOS recovery */
96 int nr_oos_count_max;
fd558d18 97 struct hlist_node hlist; /* Hash list node */
f00c854c 98 refcount_t ref_count;
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99
100 char name[32]; /* for logging */
309795f4 101 char ifname[IFNAMSIZ];
95c96174 102 unsigned int data_seq:2; /* data sequencing level
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103 * 0 => none, 1 => IP only,
104 * 2 => all
105 */
95c96174 106 unsigned int recv_seq:1; /* expect receive packets with
fd558d18 107 * sequence numbers? */
95c96174 108 unsigned int send_seq:1; /* send packets with sequence
fd558d18 109 * numbers? */
95c96174 110 unsigned int lns_mode:1; /* behave as LNS? LAC enables
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111 * sequence numbers under
112 * control of LNS. */
113 int debug; /* bitmask of debug message
114 * categories */
115 int reorder_timeout; /* configured reorder timeout
116 * (in jiffies) */
38d40b3f 117 int reorder_skip; /* set if skip to next nr */
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118 int mtu;
119 int mru;
f7faffa3 120 enum l2tp_pwtype pwtype;
fd558d18 121 struct l2tp_stats stats;
f7faffa3 122 struct hlist_node global_hlist; /* Global hash list node */
fd558d18 123
f7faffa3 124 int (*build_header)(struct l2tp_session *session, void *buf);
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125 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
126 void (*session_close)(struct l2tp_session *session);
9dd79945 127#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
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128 void (*show)(struct seq_file *m, void *priv);
129#endif
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130 uint8_t priv[0]; /* private data */
131};
132
133/* Describes the tunnel. It contains info to track all the associated
134 * sessions so incoming packets can be sorted out
135 */
136struct l2tp_tunnel_cfg {
137 int debug; /* bitmask of debug message
138 * categories */
0d76751f 139 enum l2tp_encap_type encap;
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140
141 /* Used only for kernel-created sockets */
142 struct in_addr local_ip;
143 struct in_addr peer_ip;
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144#if IS_ENABLED(CONFIG_IPV6)
145 struct in6_addr *local_ip6;
146 struct in6_addr *peer_ip6;
147#endif
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148 u16 local_udp_port;
149 u16 peer_udp_port;
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150 unsigned int use_udp_checksums:1,
151 udp6_zero_tx_checksums:1,
152 udp6_zero_rx_checksums:1;
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153};
154
155struct l2tp_tunnel {
156 int magic; /* Should be L2TP_TUNNEL_MAGIC */
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157
158 unsigned long dead;
159
99469c32 160 struct rcu_head rcu;
fd558d18 161 rwlock_t hlist_lock; /* protect session_hlist */
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162 bool acpt_newsess; /* Indicates whether this
163 * tunnel accepts new sessions.
164 * Protected by hlist_lock.
165 */
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166 struct hlist_head session_hlist[L2TP_HASH_SIZE];
167 /* hashed list of sessions,
168 * hashed by id */
169 u32 tunnel_id;
170 u32 peer_tunnel_id;
171 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
172
173 char name[20]; /* for logging */
174 int debug; /* bitmask of debug message
175 * categories */
0d76751f 176 enum l2tp_encap_type encap;
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177 struct l2tp_stats stats;
178
179 struct list_head list; /* Keep a list of all tunnels */
180 struct net *l2tp_net; /* the net we belong to */
181
fbea9e07 182 refcount_t ref_count;
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183#ifdef CONFIG_DEBUG_FS
184 void (*show)(struct seq_file *m, void *arg);
185#endif
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186 int (*recv_payload_hook)(struct sk_buff *skb);
187 void (*old_sk_destruct)(struct sock *);
188 struct sock *sock; /* Parent socket */
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189 int fd; /* Parent fd, if tunnel socket
190 * was created by userspace */
fd558d18 191
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192 struct work_struct del_work;
193
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194 uint8_t priv[0]; /* private data */
195};
196
309795f4 197struct l2tp_nl_cmd_ops {
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198 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
199 u32 session_id, u32 peer_session_id,
200 struct l2tp_session_cfg *cfg);
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201 int (*session_delete)(struct l2tp_session *session);
202};
203
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204static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
205{
206 return &tunnel->priv[0];
207}
208
209static inline void *l2tp_session_priv(struct l2tp_session *session)
210{
211 return &session->priv[0];
212}
213
54652eb1 214struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
d00fa9ad 215void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
54652eb1 216
9aaef50c 217struct l2tp_session *l2tp_session_get(const struct net *net,
61b9a047 218 struct l2tp_tunnel *tunnel,
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219 u32 session_id);
220struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
9aaef50c 221struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
a4346210 222 const char *ifname);
2f858b92 223struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
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224
225int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
226 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
227 struct l2tp_tunnel **tunnelp);
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228int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
229 struct l2tp_tunnel_cfg *cfg);
230
c1b1203d 231void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
62b982ee 232void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
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233struct l2tp_session *l2tp_session_create(int priv_size,
234 struct l2tp_tunnel *tunnel,
235 u32 session_id, u32 peer_session_id,
236 struct l2tp_session_cfg *cfg);
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237int l2tp_session_register(struct l2tp_session *session,
238 struct l2tp_tunnel *tunnel);
239
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240void __l2tp_session_unhash(struct l2tp_session *session);
241int l2tp_session_delete(struct l2tp_session *session);
242void l2tp_session_free(struct l2tp_session *session);
243void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
244 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
245 int length, int (*payload_hook)(struct sk_buff *skb));
246int l2tp_session_queue_purge(struct l2tp_session *session);
247int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
bb5016ea 248void l2tp_session_set_header_len(struct l2tp_session *session, int version);
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249
250int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
251 int hdr_len);
252
253int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
254 const struct l2tp_nl_cmd_ops *ops);
255void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
72fb96e7 256int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
309795f4 257
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258static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
259{
260 refcount_inc(&tunnel->ref_count);
261}
262
263static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
264{
265 if (refcount_dec_and_test(&tunnel->ref_count))
d00fa9ad 266 l2tp_tunnel_free(tunnel);
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267}
268
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269/* Session reference counts. Incremented when code obtains a reference
270 * to a session.
271 */
9ff672ba 272static inline void l2tp_session_inc_refcount(struct l2tp_session *session)
fd558d18 273{
f00c854c 274 refcount_inc(&session->ref_count);
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275}
276
9ff672ba 277static inline void l2tp_session_dec_refcount(struct l2tp_session *session)
fd558d18 278{
f00c854c 279 if (refcount_dec_and_test(&session->ref_count))
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280 l2tp_session_free(session);
281}
282
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283static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
284{
285 switch (session->l2specific_type) {
286 case L2TP_L2SPECTYPE_DEFAULT:
287 return 4;
288 case L2TP_L2SPECTYPE_NONE:
289 default:
290 return 0;
291 }
292}
293
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294#define l2tp_printk(ptr, type, func, fmt, ...) \
295do { \
296 if (((ptr)->debug) & (type)) \
297 func(fmt, ##__VA_ARGS__); \
298} while (0)
299
300#define l2tp_warn(ptr, type, fmt, ...) \
301 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
302#define l2tp_info(ptr, type, fmt, ...) \
303 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
304#define l2tp_dbg(ptr, type, fmt, ...) \
305 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
306
f1f39f91 307#define MODULE_ALIAS_L2TP_PWTYPE(type) \
308 MODULE_ALIAS("net-l2tp-type-" __stringify(type))
309
fd558d18 310#endif /* _L2TP_CORE_H_ */