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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#include <linux/refcount.h>
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
19/* Per tunnel, session hash table size */
20#define L2TP_HASH_BITS 4
21#define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS)
22
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
27struct sk_buff;
28
29struct l2tp_stats {
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;
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 {
47 enum l2tp_pwtype pw_type;
48 unsigned int data_seq:2; /* data sequencing level
49 * 0 => none, 1 => IP only,
50 * 2 => all
51 */
52 unsigned int recv_seq:1; /* expect receive packets with
53 * sequence numbers? */
54 unsigned int send_seq:1; /* send packets with sequence
55 * numbers? */
56 unsigned int lns_mode:1; /* behave as LNS? LAC enables
57 * sequence numbers under
58 * control of LNS. */
59 int debug; /* bitmask of debug message
60 * categories */
61 u16 vlan_id; /* VLAN pseudowire only */
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 */
67 int reorder_timeout; /* configured reorder timeout
68 * (in jiffies) */
69 int mtu;
70 int mru;
71 char *ifname;
72};
73
74struct l2tp_session {
75 int magic; /* should be
76 * L2TP_SESSION_MAGIC */
77 long dead;
78
79 struct l2tp_tunnel *tunnel; /* back pointer to tunnel
80 * context */
81 u32 session_id;
82 u32 peer_session_id;
83 u8 cookie[8];
84 int cookie_len;
85 u8 peer_cookie[8];
86 int peer_cookie_len;
87 u16 l2specific_type;
88 u16 hdr_len;
89 u32 nr; /* session NR state (receive) */
90 u32 ns; /* session NR state (send) */
91 struct sk_buff_head reorder_q; /* receive reorder queue */
92 u32 nr_max; /* max NR. Depends on tunnel */
93 u32 nr_window_size; /* NR window size */
94 u32 nr_oos; /* NR of last OOS packet */
95 int nr_oos_count; /* For OOS recovery */
96 int nr_oos_count_max;
97 struct hlist_node hlist; /* Hash list node */
98 refcount_t ref_count;
99
100 char name[32]; /* for logging */
101 char ifname[IFNAMSIZ];
102 unsigned int data_seq:2; /* data sequencing level
103 * 0 => none, 1 => IP only,
104 * 2 => all
105 */
106 unsigned int recv_seq:1; /* expect receive packets with
107 * sequence numbers? */
108 unsigned int send_seq:1; /* send packets with sequence
109 * numbers? */
110 unsigned int lns_mode:1; /* behave as LNS? LAC enables
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) */
117 int reorder_skip; /* set if skip to next nr */
118 int mtu;
119 int mru;
120 enum l2tp_pwtype pwtype;
121 struct l2tp_stats stats;
122 struct hlist_node global_hlist; /* Global hash list node */
123
124 int (*build_header)(struct l2tp_session *session, void *buf);
125 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
126 void (*session_close)(struct l2tp_session *session);
127#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
128 void (*show)(struct seq_file *m, void *priv);
129#endif
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 */
139 enum l2tp_encap_type encap;
140
141 /* Used only for kernel-created sockets */
142 struct in_addr local_ip;
143 struct in_addr peer_ip;
144#if IS_ENABLED(CONFIG_IPV6)
145 struct in6_addr *local_ip6;
146 struct in6_addr *peer_ip6;
147#endif
148 u16 local_udp_port;
149 u16 peer_udp_port;
150 unsigned int use_udp_checksums:1,
151 udp6_zero_tx_checksums:1,
152 udp6_zero_rx_checksums:1;
153};
154
155struct l2tp_tunnel {
156 int magic; /* Should be L2TP_TUNNEL_MAGIC */
157
158 unsigned long dead;
159
160 struct rcu_head rcu;
161 rwlock_t hlist_lock; /* protect session_hlist */
162 bool acpt_newsess; /* Indicates whether this
163 * tunnel accepts new sessions.
164 * Protected by hlist_lock.
165 */
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 */
176 enum l2tp_encap_type encap;
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
182 refcount_t ref_count;
183#ifdef CONFIG_DEBUG_FS
184 void (*show)(struct seq_file *m, void *arg);
185#endif
186 int (*recv_payload_hook)(struct sk_buff *skb);
187 void (*old_sk_destruct)(struct sock *);
188 struct sock *sock; /* Parent socket */
189 int fd; /* Parent fd, if tunnel socket
190 * was created by userspace */
191#if IS_ENABLED(CONFIG_IPV6)
192 bool v4mapped;
193#endif
194
195 struct work_struct del_work;
196
197 uint8_t priv[0]; /* private data */
198};
199
200struct l2tp_nl_cmd_ops {
201 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
202 u32 session_id, u32 peer_session_id,
203 struct l2tp_session_cfg *cfg);
204 int (*session_delete)(struct l2tp_session *session);
205};
206
207static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
208{
209 return &tunnel->priv[0];
210}
211
212static inline void *l2tp_session_priv(struct l2tp_session *session)
213{
214 return &session->priv[0];
215}
216
217static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
218{
219 struct l2tp_tunnel *tunnel;
220
221 if (sk == NULL)
222 return NULL;
223
224 sock_hold(sk);
225 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
226 if (tunnel == NULL) {
227 sock_put(sk);
228 goto out;
229 }
230
231 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
232
233out:
234 return tunnel;
235}
236
237struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
238
239struct l2tp_session *l2tp_session_get(const struct net *net,
240 struct l2tp_tunnel *tunnel,
241 u32 session_id);
242struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
243struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
244 const char *ifname);
245struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id);
246struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
247
248int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
249 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
250 struct l2tp_tunnel **tunnelp);
251void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
252void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
253struct l2tp_session *l2tp_session_create(int priv_size,
254 struct l2tp_tunnel *tunnel,
255 u32 session_id, u32 peer_session_id,
256 struct l2tp_session_cfg *cfg);
257int l2tp_session_register(struct l2tp_session *session,
258 struct l2tp_tunnel *tunnel);
259
260void __l2tp_session_unhash(struct l2tp_session *session);
261int l2tp_session_delete(struct l2tp_session *session);
262void l2tp_session_free(struct l2tp_session *session);
263void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
264 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
265 int length, int (*payload_hook)(struct sk_buff *skb));
266int l2tp_session_queue_purge(struct l2tp_session *session);
267int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
268void l2tp_session_set_header_len(struct l2tp_session *session, int version);
269
270int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
271 int hdr_len);
272
273int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
274 const struct l2tp_nl_cmd_ops *ops);
275void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
276int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
277
278static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
279{
280 refcount_inc(&tunnel->ref_count);
281}
282
283static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
284{
285 if (refcount_dec_and_test(&tunnel->ref_count))
286 kfree_rcu(tunnel, rcu);
287}
288
289/* Session reference counts. Incremented when code obtains a reference
290 * to a session.
291 */
292static inline void l2tp_session_inc_refcount(struct l2tp_session *session)
293{
294 refcount_inc(&session->ref_count);
295}
296
297static inline void l2tp_session_dec_refcount(struct l2tp_session *session)
298{
299 if (refcount_dec_and_test(&session->ref_count))
300 l2tp_session_free(session);
301}
302
303static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
304{
305 switch (session->l2specific_type) {
306 case L2TP_L2SPECTYPE_DEFAULT:
307 return 4;
308 case L2TP_L2SPECTYPE_NONE:
309 default:
310 return 0;
311 }
312}
313
314#define l2tp_printk(ptr, type, func, fmt, ...) \
315do { \
316 if (((ptr)->debug) & (type)) \
317 func(fmt, ##__VA_ARGS__); \
318} while (0)
319
320#define l2tp_warn(ptr, type, fmt, ...) \
321 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
322#define l2tp_info(ptr, type, fmt, ...) \
323 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
324#define l2tp_dbg(ptr, type, fmt, ...) \
325 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
326
327#define MODULE_ALIAS_L2TP_PWTYPE(type) \
328 MODULE_ALIAS("net-l2tp-type-" __stringify(type))
329
330#endif /* _L2TP_CORE_H_ */