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l2tp: take reference on sessions being dumped
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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 */
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
f7faffa3 18/* Per tunnel, session hash table size */
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19#define L2TP_HASH_BITS 4
20#define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS)
21
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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
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26struct sk_buff;
27
28struct l2tp_stats {
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29 atomic_long_t tx_packets;
30 atomic_long_t tx_bytes;
31 atomic_long_t tx_errors;
32 atomic_long_t rx_packets;
33 atomic_long_t rx_bytes;
34 atomic_long_t rx_seq_discards;
35 atomic_long_t rx_oos_packets;
36 atomic_long_t rx_errors;
37 atomic_long_t rx_cookie_discards;
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38};
39
40struct l2tp_tunnel;
41
42/* Describes a session. Contains information to determine incoming
43 * packets and transmit outgoing ones.
44 */
45struct l2tp_session_cfg {
f7faffa3 46 enum l2tp_pwtype pw_type;
95c96174 47 unsigned int data_seq:2; /* data sequencing level
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48 * 0 => none, 1 => IP only,
49 * 2 => all
50 */
95c96174 51 unsigned int recv_seq:1; /* expect receive packets with
fd558d18 52 * sequence numbers? */
95c96174 53 unsigned int send_seq:1; /* send packets with sequence
fd558d18 54 * numbers? */
95c96174 55 unsigned int lns_mode:1; /* behave as LNS? LAC enables
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56 * sequence numbers under
57 * control of LNS. */
58 int debug; /* bitmask of debug message
59 * categories */
309795f4 60 u16 vlan_id; /* VLAN pseudowire only */
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61 u16 offset; /* offset to payload */
62 u16 l2specific_len; /* Layer 2 specific length */
63 u16 l2specific_type; /* Layer 2 specific type */
64 u8 cookie[8]; /* optional cookie */
65 int cookie_len; /* 0, 4 or 8 bytes */
66 u8 peer_cookie[8]; /* peer's cookie */
67 int peer_cookie_len; /* 0, 4 or 8 bytes */
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68 int reorder_timeout; /* configured reorder timeout
69 * (in jiffies) */
70 int mtu;
71 int mru;
309795f4 72 char *ifname;
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73};
74
75struct l2tp_session {
76 int magic; /* should be
77 * L2TP_SESSION_MAGIC */
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;
87 u16 offset; /* offset from end of L2TP header
88 to beginning of data */
89 u16 l2specific_len;
90 u16 l2specific_type;
91 u16 hdr_len;
92 u32 nr; /* session NR state (receive) */
93 u32 ns; /* session NR state (send) */
fd558d18 94 struct sk_buff_head reorder_q; /* receive reorder queue */
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95 u32 nr_max; /* max NR. Depends on tunnel */
96 u32 nr_window_size; /* NR window size */
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97 u32 nr_oos; /* NR of last OOS packet */
98 int nr_oos_count; /* For OOS recovery */
99 int nr_oos_count_max;
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100 struct hlist_node hlist; /* Hash list node */
101 atomic_t ref_count;
102
103 char name[32]; /* for logging */
309795f4 104 char ifname[IFNAMSIZ];
95c96174 105 unsigned int data_seq:2; /* data sequencing level
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106 * 0 => none, 1 => IP only,
107 * 2 => all
108 */
95c96174 109 unsigned int recv_seq:1; /* expect receive packets with
fd558d18 110 * sequence numbers? */
95c96174 111 unsigned int send_seq:1; /* send packets with sequence
fd558d18 112 * numbers? */
95c96174 113 unsigned int lns_mode:1; /* behave as LNS? LAC enables
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114 * sequence numbers under
115 * control of LNS. */
116 int debug; /* bitmask of debug message
117 * categories */
118 int reorder_timeout; /* configured reorder timeout
119 * (in jiffies) */
38d40b3f 120 int reorder_skip; /* set if skip to next nr */
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121 int mtu;
122 int mru;
f7faffa3 123 enum l2tp_pwtype pwtype;
fd558d18 124 struct l2tp_stats stats;
f7faffa3 125 struct hlist_node global_hlist; /* Global hash list node */
fd558d18 126
f7faffa3 127 int (*build_header)(struct l2tp_session *session, void *buf);
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128 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
129 void (*session_close)(struct l2tp_session *session);
130 void (*ref)(struct l2tp_session *session);
131 void (*deref)(struct l2tp_session *session);
9dd79945 132#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
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133 void (*show)(struct seq_file *m, void *priv);
134#endif
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135 uint8_t priv[0]; /* private data */
136};
137
138/* Describes the tunnel. It contains info to track all the associated
139 * sessions so incoming packets can be sorted out
140 */
141struct l2tp_tunnel_cfg {
142 int debug; /* bitmask of debug message
143 * categories */
0d76751f 144 enum l2tp_encap_type encap;
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145
146 /* Used only for kernel-created sockets */
147 struct in_addr local_ip;
148 struct in_addr peer_ip;
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149#if IS_ENABLED(CONFIG_IPV6)
150 struct in6_addr *local_ip6;
151 struct in6_addr *peer_ip6;
152#endif
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153 u16 local_udp_port;
154 u16 peer_udp_port;
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155 unsigned int use_udp_checksums:1,
156 udp6_zero_tx_checksums:1,
157 udp6_zero_rx_checksums:1;
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158};
159
160struct l2tp_tunnel {
161 int magic; /* Should be L2TP_TUNNEL_MAGIC */
99469c32 162 struct rcu_head rcu;
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163 rwlock_t hlist_lock; /* protect session_hlist */
164 struct hlist_head session_hlist[L2TP_HASH_SIZE];
165 /* hashed list of sessions,
166 * hashed by id */
167 u32 tunnel_id;
168 u32 peer_tunnel_id;
169 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
170
171 char name[20]; /* for logging */
172 int debug; /* bitmask of debug message
173 * categories */
0d76751f 174 enum l2tp_encap_type encap;
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175 struct l2tp_stats stats;
176
177 struct list_head list; /* Keep a list of all tunnels */
178 struct net *l2tp_net; /* the net we belong to */
179
180 atomic_t ref_count;
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181#ifdef CONFIG_DEBUG_FS
182 void (*show)(struct seq_file *m, void *arg);
183#endif
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184 int (*recv_payload_hook)(struct sk_buff *skb);
185 void (*old_sk_destruct)(struct sock *);
186 struct sock *sock; /* Parent socket */
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187 int fd; /* Parent fd, if tunnel socket
188 * was created by userspace */
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189#if IS_ENABLED(CONFIG_IPV6)
190 bool v4mapped;
191#endif
fd558d18 192
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193 struct work_struct del_work;
194
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195 uint8_t priv[0]; /* private data */
196};
197
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198struct l2tp_nl_cmd_ops {
199 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
200 int (*session_delete)(struct l2tp_session *session);
201};
202
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203static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
204{
205 return &tunnel->priv[0];
206}
207
208static inline void *l2tp_session_priv(struct l2tp_session *session)
209{
210 return &session->priv[0];
211}
212
213static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
214{
215 struct l2tp_tunnel *tunnel;
216
217 if (sk == NULL)
218 return NULL;
219
220 sock_hold(sk);
221 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
222 if (tunnel == NULL) {
223 sock_put(sk);
224 goto out;
225 }
226
227 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
228
229out:
230 return tunnel;
231}
232
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233struct l2tp_session *l2tp_session_get(struct net *net,
234 struct l2tp_tunnel *tunnel,
235 u32 session_id, bool do_ref);
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236struct l2tp_session *l2tp_session_find(struct net *net,
237 struct l2tp_tunnel *tunnel,
238 u32 session_id);
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239struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
240 bool do_ref);
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241struct l2tp_session *l2tp_session_get_by_ifname(struct net *net, char *ifname,
242 bool do_ref);
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243struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
244struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
245
246int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
247 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
248 struct l2tp_tunnel **tunnelp);
249void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
250int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
251struct l2tp_session *l2tp_session_create(int priv_size,
252 struct l2tp_tunnel *tunnel,
253 u32 session_id, u32 peer_session_id,
254 struct l2tp_session_cfg *cfg);
255void __l2tp_session_unhash(struct l2tp_session *session);
256int l2tp_session_delete(struct l2tp_session *session);
257void l2tp_session_free(struct l2tp_session *session);
258void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
259 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
260 int length, int (*payload_hook)(struct sk_buff *skb));
261int l2tp_session_queue_purge(struct l2tp_session *session);
262int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
bb5016ea 263void l2tp_session_set_header_len(struct l2tp_session *session, int version);
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264
265int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
266 int hdr_len);
267
268int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
269 const struct l2tp_nl_cmd_ops *ops);
270void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
72fb96e7 271int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
309795f4 272
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273/* Session reference counts. Incremented when code obtains a reference
274 * to a session.
275 */
276static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
277{
278 atomic_inc(&session->ref_count);
279}
280
281static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
282{
283 if (atomic_dec_and_test(&session->ref_count))
284 l2tp_session_free(session);
285}
286
287#ifdef L2TP_REFCNT_DEBUG
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288#define l2tp_session_inc_refcount(_s) \
289do { \
290 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \
291 __func__, __LINE__, (_s)->name, \
292 atomic_read(&_s->ref_count)); \
293 l2tp_session_inc_refcount_1(_s); \
294} while (0)
295#define l2tp_session_dec_refcount(_s) \
296do { \
297 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \
298 __func__, __LINE__, (_s)->name, \
299 atomic_read(&_s->ref_count)); \
300 l2tp_session_dec_refcount_1(_s); \
301} while (0)
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302#else
303#define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
304#define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
305#endif
306
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307#define l2tp_printk(ptr, type, func, fmt, ...) \
308do { \
309 if (((ptr)->debug) & (type)) \
310 func(fmt, ##__VA_ARGS__); \
311} while (0)
312
313#define l2tp_warn(ptr, type, fmt, ...) \
314 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
315#define l2tp_info(ptr, type, fmt, ...) \
316 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
317#define l2tp_dbg(ptr, type, fmt, ...) \
318 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
319
f1f39f91 320#define MODULE_ALIAS_L2TP_PWTYPE(type) \
321 MODULE_ALIAS("net-l2tp-type-" __stringify(type))
322
fd558d18 323#endif /* _L2TP_CORE_H_ */