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l2tp: initialise session's refcount before making it reachable
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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 offset; /* offset to payload */
63 u16 l2specific_len; /* Layer 2 specific length */
64 u16 l2specific_type; /* Layer 2 specific type */
65 u8 cookie[8]; /* optional cookie */
66 int cookie_len; /* 0, 4 or 8 bytes */
67 u8 peer_cookie[8]; /* peer's cookie */
68 int peer_cookie_len; /* 0, 4 or 8 bytes */
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69 int reorder_timeout; /* configured reorder timeout
70 * (in jiffies) */
71 int mtu;
72 int mru;
309795f4 73 char *ifname;
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74};
75
76struct l2tp_session {
77 int magic; /* should be
78 * L2TP_SESSION_MAGIC */
79
80 struct l2tp_tunnel *tunnel; /* back pointer to tunnel
81 * context */
82 u32 session_id;
83 u32 peer_session_id;
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84 u8 cookie[8];
85 int cookie_len;
86 u8 peer_cookie[8];
87 int peer_cookie_len;
88 u16 offset; /* offset from end of L2TP header
89 to beginning of data */
90 u16 l2specific_len;
91 u16 l2specific_type;
92 u16 hdr_len;
93 u32 nr; /* session NR state (receive) */
94 u32 ns; /* session NR state (send) */
fd558d18 95 struct sk_buff_head reorder_q; /* receive reorder queue */
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96 u32 nr_max; /* max NR. Depends on tunnel */
97 u32 nr_window_size; /* NR window size */
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98 u32 nr_oos; /* NR of last OOS packet */
99 int nr_oos_count; /* For OOS recovery */
100 int nr_oos_count_max;
fd558d18 101 struct hlist_node hlist; /* Hash list node */
f00c854c 102 refcount_t ref_count;
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103
104 char name[32]; /* for logging */
309795f4 105 char ifname[IFNAMSIZ];
95c96174 106 unsigned int data_seq:2; /* data sequencing level
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107 * 0 => none, 1 => IP only,
108 * 2 => all
109 */
95c96174 110 unsigned int recv_seq:1; /* expect receive packets with
fd558d18 111 * sequence numbers? */
95c96174 112 unsigned int send_seq:1; /* send packets with sequence
fd558d18 113 * numbers? */
95c96174 114 unsigned int lns_mode:1; /* behave as LNS? LAC enables
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115 * sequence numbers under
116 * control of LNS. */
117 int debug; /* bitmask of debug message
118 * categories */
119 int reorder_timeout; /* configured reorder timeout
120 * (in jiffies) */
38d40b3f 121 int reorder_skip; /* set if skip to next nr */
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122 int mtu;
123 int mru;
f7faffa3 124 enum l2tp_pwtype pwtype;
fd558d18 125 struct l2tp_stats stats;
f7faffa3 126 struct hlist_node global_hlist; /* Global hash list node */
fd558d18 127
f7faffa3 128 int (*build_header)(struct l2tp_session *session, void *buf);
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129 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
130 void (*session_close)(struct l2tp_session *session);
131 void (*ref)(struct l2tp_session *session);
132 void (*deref)(struct l2tp_session *session);
9dd79945 133#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
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134 void (*show)(struct seq_file *m, void *priv);
135#endif
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136 uint8_t priv[0]; /* private data */
137};
138
139/* Describes the tunnel. It contains info to track all the associated
140 * sessions so incoming packets can be sorted out
141 */
142struct l2tp_tunnel_cfg {
143 int debug; /* bitmask of debug message
144 * categories */
0d76751f 145 enum l2tp_encap_type encap;
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146
147 /* Used only for kernel-created sockets */
148 struct in_addr local_ip;
149 struct in_addr peer_ip;
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150#if IS_ENABLED(CONFIG_IPV6)
151 struct in6_addr *local_ip6;
152 struct in6_addr *peer_ip6;
153#endif
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154 u16 local_udp_port;
155 u16 peer_udp_port;
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156 unsigned int use_udp_checksums:1,
157 udp6_zero_tx_checksums:1,
158 udp6_zero_rx_checksums:1;
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159};
160
161struct l2tp_tunnel {
162 int magic; /* Should be L2TP_TUNNEL_MAGIC */
99469c32 163 struct rcu_head rcu;
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164 rwlock_t hlist_lock; /* protect session_hlist */
165 struct hlist_head session_hlist[L2TP_HASH_SIZE];
166 /* hashed list of sessions,
167 * hashed by id */
168 u32 tunnel_id;
169 u32 peer_tunnel_id;
170 int version; /* 2=>L2TPv2, 3=>L2TPv3 */
171
172 char name[20]; /* for logging */
173 int debug; /* bitmask of debug message
174 * categories */
0d76751f 175 enum l2tp_encap_type encap;
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176 struct l2tp_stats stats;
177
178 struct list_head list; /* Keep a list of all tunnels */
179 struct net *l2tp_net; /* the net we belong to */
180
fbea9e07 181 refcount_t ref_count;
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182#ifdef CONFIG_DEBUG_FS
183 void (*show)(struct seq_file *m, void *arg);
184#endif
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185 int (*recv_payload_hook)(struct sk_buff *skb);
186 void (*old_sk_destruct)(struct sock *);
187 struct sock *sock; /* Parent socket */
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188 int fd; /* Parent fd, if tunnel socket
189 * was created by userspace */
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190#if IS_ENABLED(CONFIG_IPV6)
191 bool v4mapped;
192#endif
fd558d18 193
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194 struct work_struct del_work;
195
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196 uint8_t priv[0]; /* private data */
197};
198
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199struct l2tp_nl_cmd_ops {
200 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
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
214static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
215{
216 struct l2tp_tunnel *tunnel;
217
218 if (sk == NULL)
219 return NULL;
220
221 sock_hold(sk);
222 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
223 if (tunnel == NULL) {
224 sock_put(sk);
225 goto out;
226 }
227
228 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
229
230out:
231 return tunnel;
232}
233
9aaef50c 234struct l2tp_session *l2tp_session_get(const struct net *net,
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235 struct l2tp_tunnel *tunnel,
236 u32 session_id, bool do_ref);
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237struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
238 bool do_ref);
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239struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
240 const char *ifname,
2777e2ab 241 bool do_ref);
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242struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id);
243struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
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244
245int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
246 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
247 struct l2tp_tunnel **tunnelp);
248void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
249int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
250struct l2tp_session *l2tp_session_create(int priv_size,
251 struct l2tp_tunnel *tunnel,
252 u32 session_id, u32 peer_session_id,
253 struct l2tp_session_cfg *cfg);
254void __l2tp_session_unhash(struct l2tp_session *session);
255int l2tp_session_delete(struct l2tp_session *session);
256void l2tp_session_free(struct l2tp_session *session);
257void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
258 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
259 int length, int (*payload_hook)(struct sk_buff *skb));
260int l2tp_session_queue_purge(struct l2tp_session *session);
261int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
bb5016ea 262void l2tp_session_set_header_len(struct l2tp_session *session, int version);
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263
264int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
265 int hdr_len);
266
267int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
268 const struct l2tp_nl_cmd_ops *ops);
269void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
72fb96e7 270int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
309795f4 271
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272/* Session reference counts. Incremented when code obtains a reference
273 * to a session.
274 */
275static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
276{
f00c854c 277 refcount_inc(&session->ref_count);
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278}
279
280static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
281{
f00c854c 282 if (refcount_dec_and_test(&session->ref_count))
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283 l2tp_session_free(session);
284}
285
286#ifdef L2TP_REFCNT_DEBUG
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287#define l2tp_session_inc_refcount(_s) \
288do { \
289 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \
290 __func__, __LINE__, (_s)->name, \
f00c854c 291 refcount_read(&_s->ref_count)); \
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292 l2tp_session_inc_refcount_1(_s); \
293} while (0)
294#define l2tp_session_dec_refcount(_s) \
295do { \
296 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \
297 __func__, __LINE__, (_s)->name, \
f00c854c 298 refcount_read(&_s->ref_count)); \
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299 l2tp_session_dec_refcount_1(_s); \
300} while (0)
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301#else
302#define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
303#define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
304#endif
305
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306#define l2tp_printk(ptr, type, func, fmt, ...) \
307do { \
308 if (((ptr)->debug) & (type)) \
309 func(fmt, ##__VA_ARGS__); \
310} while (0)
311
312#define l2tp_warn(ptr, type, fmt, ...) \
313 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
314#define l2tp_info(ptr, type, fmt, ...) \
315 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
316#define l2tp_dbg(ptr, type, fmt, ...) \
317 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
318
f1f39f91 319#define MODULE_ALIAS_L2TP_PWTYPE(type) \
320 MODULE_ALIAS("net-l2tp-type-" __stringify(type))
321
fd558d18 322#endif /* _L2TP_CORE_H_ */