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d2912cb1 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
20dcb110 | 2 | /* L2TP internal definitions. |
fd558d18 JC |
3 | * |
4 | * Copyright (c) 2008,2009 Katalix Systems Ltd | |
fd558d18 | 5 | */ |
fbea9e07 | 6 | #include <linux/refcount.h> |
fd558d18 JC |
7 | |
8 | #ifndef _L2TP_CORE_H_ | |
9 | #define _L2TP_CORE_H_ | |
10 | ||
1f5cd2a0 GN |
11 | #include <net/dst.h> |
12 | #include <net/sock.h> | |
13 | ||
d6a61ec9 GN |
14 | #ifdef CONFIG_XFRM |
15 | #include <net/xfrm.h> | |
16 | #endif | |
17 | ||
340bb1ac | 18 | /* Random numbers used for internal consistency checks of tunnel and session structures */ |
fd558d18 JC |
19 | #define L2TP_TUNNEL_MAGIC 0x42114DDA |
20 | #define L2TP_SESSION_MAGIC 0x0C04EB7D | |
21 | ||
340bb1ac | 22 | /* Per tunnel session hash table size */ |
fd558d18 | 23 | #define L2TP_HASH_BITS 4 |
dbf82f3f | 24 | #define L2TP_HASH_SIZE BIT(L2TP_HASH_BITS) |
fd558d18 | 25 | |
340bb1ac | 26 | /* System-wide session hash table size */ |
f7faffa3 | 27 | #define L2TP_HASH_BITS_2 8 |
dbf82f3f | 28 | #define L2TP_HASH_SIZE_2 BIT(L2TP_HASH_BITS_2) |
f7faffa3 | 29 | |
fd558d18 JC |
30 | struct sk_buff; |
31 | ||
32 | struct l2tp_stats { | |
7b7c0719 TP |
33 | atomic_long_t tx_packets; |
34 | atomic_long_t tx_bytes; | |
35 | atomic_long_t tx_errors; | |
36 | atomic_long_t rx_packets; | |
37 | atomic_long_t rx_bytes; | |
38 | atomic_long_t rx_seq_discards; | |
39 | atomic_long_t rx_oos_packets; | |
40 | atomic_long_t rx_errors; | |
41 | atomic_long_t rx_cookie_discards; | |
3e59e885 | 42 | atomic_long_t rx_invalid; |
fd558d18 JC |
43 | }; |
44 | ||
45 | struct l2tp_tunnel; | |
46 | ||
340bb1ac | 47 | /* L2TP session configuration */ |
fd558d18 | 48 | struct l2tp_session_cfg { |
f7faffa3 | 49 | enum l2tp_pwtype pw_type; |
20dcb110 TP |
50 | unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */ |
51 | unsigned int send_seq:1; /* send packets with sequence numbers? */ | |
52 | unsigned int lns_mode:1; /* behave as LNS? | |
53 | * LAC enables sequence numbers under LNS control. | |
54 | */ | |
f7faffa3 JC |
55 | u16 l2specific_type; /* Layer 2 specific type */ |
56 | u8 cookie[8]; /* optional cookie */ | |
57 | int cookie_len; /* 0, 4 or 8 bytes */ | |
58 | u8 peer_cookie[8]; /* peer's cookie */ | |
59 | int peer_cookie_len; /* 0, 4 or 8 bytes */ | |
20dcb110 | 60 | int reorder_timeout; /* configured reorder timeout (in jiffies) */ |
309795f4 | 61 | char *ifname; |
fd558d18 JC |
62 | }; |
63 | ||
340bb1ac TP |
64 | /* Represents a session (pseudowire) instance. |
65 | * Tracks runtime state including cookies, dataplane packet sequencing, and IO statistics. | |
66 | * Is linked into a per-tunnel session hashlist; and in the case of an L2TPv3 session into | |
67 | * an additional per-net ("global") hashlist. | |
68 | */ | |
2a03dd8e | 69 | #define L2TP_SESSION_NAME_MAX 32 |
fd558d18 | 70 | struct l2tp_session { |
20dcb110 | 71 | int magic; /* should be L2TP_SESSION_MAGIC */ |
b228a940 | 72 | long dead; |
fd558d18 | 73 | |
20dcb110 | 74 | struct l2tp_tunnel *tunnel; /* back pointer to tunnel context */ |
fd558d18 JC |
75 | u32 session_id; |
76 | u32 peer_session_id; | |
f7faffa3 JC |
77 | u8 cookie[8]; |
78 | int cookie_len; | |
79 | u8 peer_cookie[8]; | |
80 | int peer_cookie_len; | |
f7faffa3 JC |
81 | u16 l2specific_type; |
82 | u16 hdr_len; | |
83 | u32 nr; /* session NR state (receive) */ | |
84 | u32 ns; /* session NR state (send) */ | |
fd558d18 | 85 | struct sk_buff_head reorder_q; /* receive reorder queue */ |
8a1631d5 JC |
86 | u32 nr_max; /* max NR. Depends on tunnel */ |
87 | u32 nr_window_size; /* NR window size */ | |
a0dbd822 | 88 | u32 nr_oos; /* NR of last OOS packet */ |
20dcb110 | 89 | int nr_oos_count; /* for OOS recovery */ |
a0dbd822 | 90 | int nr_oos_count_max; |
20dcb110 | 91 | struct hlist_node hlist; /* hash list node */ |
f00c854c | 92 | refcount_t ref_count; |
fd558d18 | 93 | |
2a03dd8e | 94 | char name[L2TP_SESSION_NAME_MAX]; /* for logging */ |
309795f4 | 95 | char ifname[IFNAMSIZ]; |
20dcb110 TP |
96 | unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */ |
97 | unsigned int send_seq:1; /* send packets with sequence numbers? */ | |
98 | unsigned int lns_mode:1; /* behave as LNS? | |
99 | * LAC enables sequence numbers under LNS control. | |
100 | */ | |
20dcb110 | 101 | int reorder_timeout; /* configured reorder timeout (in jiffies) */ |
38d40b3f | 102 | int reorder_skip; /* set if skip to next nr */ |
f7faffa3 | 103 | enum l2tp_pwtype pwtype; |
fd558d18 | 104 | struct l2tp_stats stats; |
20dcb110 | 105 | struct hlist_node global_hlist; /* global hash list node */ |
fd558d18 | 106 | |
340bb1ac TP |
107 | /* Session receive handler for data packets. |
108 | * Each pseudowire implementation should implement this callback in order to | |
109 | * handle incoming packets. Packets are passed to the pseudowire handler after | |
110 | * reordering, if data sequence numbers are enabled for the session. | |
111 | */ | |
fd558d18 | 112 | void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); |
340bb1ac TP |
113 | |
114 | /* Session close handler. | |
115 | * Each pseudowire implementation may implement this callback in order to carry | |
116 | * out pseudowire-specific shutdown actions. | |
117 | * The callback is called by core after unhashing the session and purging its | |
118 | * reorder queue. | |
119 | */ | |
fd558d18 | 120 | void (*session_close)(struct l2tp_session *session); |
340bb1ac TP |
121 | |
122 | /* Session show handler. | |
123 | * Pseudowire-specific implementation of debugfs session rendering. | |
124 | * The callback is called by l2tp_debugfs.c after rendering core session | |
125 | * information. | |
126 | */ | |
0ad66140 | 127 | void (*show)(struct seq_file *m, void *priv); |
340bb1ac | 128 | |
20dcb110 | 129 | u8 priv[]; /* private data */ |
fd558d18 JC |
130 | }; |
131 | ||
340bb1ac | 132 | /* L2TP tunnel configuration */ |
fd558d18 | 133 | struct l2tp_tunnel_cfg { |
0d76751f | 134 | enum l2tp_encap_type encap; |
789a4a2c JC |
135 | |
136 | /* Used only for kernel-created sockets */ | |
137 | struct in_addr local_ip; | |
138 | struct in_addr peer_ip; | |
f9bac8df CE |
139 | #if IS_ENABLED(CONFIG_IPV6) |
140 | struct in6_addr *local_ip6; | |
141 | struct in6_addr *peer_ip6; | |
142 | #endif | |
789a4a2c JC |
143 | u16 local_udp_port; |
144 | u16 peer_udp_port; | |
6b649fea TH |
145 | unsigned int use_udp_checksums:1, |
146 | udp6_zero_tx_checksums:1, | |
147 | udp6_zero_rx_checksums:1; | |
fd558d18 JC |
148 | }; |
149 | ||
340bb1ac TP |
150 | /* Represents a tunnel instance. |
151 | * Tracks runtime state including IO statistics. | |
152 | * Holds the tunnel socket (either passed from userspace or directly created by the kernel). | |
153 | * Maintains a hashlist of sessions belonging to the tunnel instance. | |
154 | * Is linked into a per-net list of tunnels. | |
155 | */ | |
2a03dd8e | 156 | #define L2TP_TUNNEL_NAME_MAX 20 |
fd558d18 JC |
157 | struct l2tp_tunnel { |
158 | int magic; /* Should be L2TP_TUNNEL_MAGIC */ | |
62b982ee SD |
159 | |
160 | unsigned long dead; | |
161 | ||
99469c32 | 162 | struct rcu_head rcu; |
07b8ca37 | 163 | spinlock_t hlist_lock; /* write-protection for session_hlist */ |
20dcb110 TP |
164 | bool acpt_newsess; /* indicates whether this tunnel accepts |
165 | * new sessions. Protected by hlist_lock. | |
f3c66d4e | 166 | */ |
fd558d18 | 167 | struct hlist_head session_hlist[L2TP_HASH_SIZE]; |
20dcb110 | 168 | /* hashed list of sessions, hashed by id */ |
fd558d18 JC |
169 | u32 tunnel_id; |
170 | u32 peer_tunnel_id; | |
171 | int version; /* 2=>L2TPv2, 3=>L2TPv3 */ | |
172 | ||
2a03dd8e | 173 | char name[L2TP_TUNNEL_NAME_MAX]; /* for logging */ |
0d76751f | 174 | enum l2tp_encap_type encap; |
fd558d18 JC |
175 | struct l2tp_stats stats; |
176 | ||
20dcb110 | 177 | struct list_head list; /* list node on per-namespace list of tunnels */ |
fd558d18 JC |
178 | struct net *l2tp_net; /* the net we belong to */ |
179 | ||
fbea9e07 | 180 | refcount_t ref_count; |
bef04d16 | 181 | void (*old_sk_destruct)(struct sock *sk); |
20dcb110 TP |
182 | struct sock *sock; /* parent socket */ |
183 | int fd; /* parent fd, if tunnel socket was created | |
184 | * by userspace | |
185 | */ | |
fd558d18 | 186 | |
f8ccac0e | 187 | struct work_struct del_work; |
fd558d18 JC |
188 | }; |
189 | ||
340bb1ac | 190 | /* Pseudowire ops callbacks for use with the l2tp genetlink interface */ |
309795f4 | 191 | struct l2tp_nl_cmd_ops { |
340bb1ac TP |
192 | /* The pseudowire session create callback is responsible for creating a session |
193 | * instance for a specific pseudowire type. | |
194 | * It must call l2tp_session_create and l2tp_session_register to register the | |
195 | * session instance, as well as carry out any pseudowire-specific initialisation. | |
196 | * It must return >= 0 on success, or an appropriate negative errno value on failure. | |
197 | */ | |
f026bc29 GN |
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); | |
340bb1ac TP |
201 | |
202 | /* The pseudowire session delete callback is responsible for initiating the deletion | |
203 | * of a session instance. | |
204 | * It must call l2tp_session_delete, as well as carry out any pseudowire-specific | |
205 | * teardown actions. | |
206 | */ | |
628703f5 | 207 | void (*session_delete)(struct l2tp_session *session); |
309795f4 JC |
208 | }; |
209 | ||
fd558d18 JC |
210 | static inline void *l2tp_session_priv(struct l2tp_session *session) |
211 | { | |
212 | return &session->priv[0]; | |
213 | } | |
214 | ||
340bb1ac | 215 | /* Tunnel and session refcounts */ |
52016e25 TP |
216 | void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel); |
217 | void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel); | |
218 | void l2tp_session_inc_refcount(struct l2tp_session *session); | |
219 | void l2tp_session_dec_refcount(struct l2tp_session *session); | |
220 | ||
340bb1ac TP |
221 | /* Tunnel and session lookup. |
222 | * These functions take a reference on the instances they return, so | |
223 | * the caller must ensure that the reference is dropped appropriately. | |
224 | */ | |
54652eb1 | 225 | struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id); |
5846c131 | 226 | struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth); |
01e28b92 GN |
227 | struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel, |
228 | u32 session_id); | |
5846c131 | 229 | |
01e28b92 | 230 | struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id); |
a4346210 | 231 | struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth); |
9aaef50c | 232 | struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, |
a4346210 | 233 | const char *ifname); |
c1b1203d | 234 | |
340bb1ac TP |
235 | /* Tunnel and session lifetime management. |
236 | * Creation of a new instance is a two-step process: create, then register. | |
237 | * Destruction is triggered using the *_delete functions, and completes asynchronously. | |
238 | */ | |
c9ccd4c6 | 239 | int l2tp_tunnel_create(int fd, int version, u32 tunnel_id, |
c1b1203d JP |
240 | u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, |
241 | struct l2tp_tunnel **tunnelp); | |
6b9f3423 GN |
242 | int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, |
243 | struct l2tp_tunnel_cfg *cfg); | |
62b982ee | 244 | void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); |
340bb1ac | 245 | |
c1b1203d JP |
246 | struct l2tp_session *l2tp_session_create(int priv_size, |
247 | struct l2tp_tunnel *tunnel, | |
248 | u32 session_id, u32 peer_session_id, | |
249 | struct l2tp_session_cfg *cfg); | |
3953ae7b GN |
250 | int l2tp_session_register(struct l2tp_session *session, |
251 | struct l2tp_tunnel *tunnel); | |
628703f5 | 252 | void l2tp_session_delete(struct l2tp_session *session); |
340bb1ac TP |
253 | |
254 | /* Receive path helpers. If data sequencing is enabled for the session these | |
255 | * functions handle queuing and reordering prior to passing packets to the | |
256 | * pseudowire code to be passed to userspace. | |
257 | */ | |
c1b1203d JP |
258 | void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, |
259 | unsigned char *ptr, unsigned char *optr, u16 hdrflags, | |
2b139e6b | 260 | int length); |
c1b1203d JP |
261 | int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); |
262 | ||
340bb1ac TP |
263 | /* Transmit path helpers for sending packets over the tunnel socket. */ |
264 | void l2tp_session_set_header_len(struct l2tp_session *session, int version); | |
efe05278 | 265 | int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb); |
c1b1203d | 266 | |
340bb1ac TP |
267 | /* Pseudowire management. |
268 | * Pseudowires should register with l2tp core on module init, and unregister | |
269 | * on module exit. | |
270 | */ | |
271 | int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops); | |
c1b1203d | 272 | void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); |
340bb1ac TP |
273 | |
274 | /* IOCTL helper for IP encap modules. */ | |
72fb96e7 | 275 | int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); |
309795f4 | 276 | |
45faeff1 TP |
277 | /* Extract the tunnel structure from a socket's sk_user_data pointer, |
278 | * validating the tunnel magic feather. | |
279 | */ | |
280 | struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk); | |
281 | ||
62e7b6a5 LB |
282 | static inline int l2tp_get_l2specific_len(struct l2tp_session *session) |
283 | { | |
284 | switch (session->l2specific_type) { | |
285 | case L2TP_L2SPECTYPE_DEFAULT: | |
286 | return 4; | |
287 | case L2TP_L2SPECTYPE_NONE: | |
288 | default: | |
289 | return 0; | |
290 | } | |
291 | } | |
292 | ||
1f5cd2a0 GN |
293 | static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel) |
294 | { | |
295 | struct dst_entry *dst; | |
296 | u32 mtu; | |
297 | ||
298 | dst = sk_dst_get(tunnel->sock); | |
299 | if (!dst) | |
300 | return 0; | |
301 | ||
302 | mtu = dst_mtu(dst); | |
303 | dst_release(dst); | |
304 | ||
305 | return mtu; | |
306 | } | |
307 | ||
d6a61ec9 GN |
308 | #ifdef CONFIG_XFRM |
309 | static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel) | |
310 | { | |
311 | struct sock *sk = tunnel->sock; | |
312 | ||
313 | return sk && (rcu_access_pointer(sk->sk_policy[0]) || | |
314 | rcu_access_pointer(sk->sk_policy[1])); | |
315 | } | |
316 | #else | |
317 | static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel) | |
318 | { | |
319 | return false; | |
320 | } | |
321 | #endif | |
322 | ||
4522a70d JW |
323 | static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb, |
324 | unsigned char **ptr, unsigned char **optr) | |
325 | { | |
326 | int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session); | |
327 | ||
328 | if (opt_len > 0) { | |
329 | int off = *ptr - *optr; | |
330 | ||
331 | if (!pskb_may_pull(skb, off + opt_len)) | |
332 | return -1; | |
333 | ||
334 | if (skb->data != *optr) { | |
335 | *optr = skb->data; | |
336 | *ptr = skb->data + off; | |
337 | } | |
338 | } | |
339 | ||
340 | return 0; | |
341 | } | |
342 | ||
f1f39f91 | 343 | #define MODULE_ALIAS_L2TP_PWTYPE(type) \ |
344 | MODULE_ALIAS("net-l2tp-type-" __stringify(type)) | |
345 | ||
fd558d18 | 346 | #endif /* _L2TP_CORE_H_ */ |