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 #include <net/dst.h> 16 #include <net/sock.h> 17 18 #ifdef CONFIG_XFRM 19 #include <net/xfrm.h> 20 #endif 21 22 /* Just some random numbers */ 23 #define L2TP_TUNNEL_MAGIC 0x42114DDA 24 #define L2TP_SESSION_MAGIC 0x0C04EB7D 25 26 /* Per tunnel, session hash table size */ 27 #define L2TP_HASH_BITS 4 28 #define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS) 29 30 /* System-wide, session hash table size */ 31 #define L2TP_HASH_BITS_2 8 32 #define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2) 33 34 struct sk_buff; 35 36 struct l2tp_stats { 37 atomic_long_t tx_packets; 38 atomic_long_t tx_bytes; 39 atomic_long_t tx_errors; 40 atomic_long_t rx_packets; 41 atomic_long_t rx_bytes; 42 atomic_long_t rx_seq_discards; 43 atomic_long_t rx_oos_packets; 44 atomic_long_t rx_errors; 45 atomic_long_t rx_cookie_discards; 46 }; 47 48 struct l2tp_tunnel; 49 50 /* Describes a session. Contains information to determine incoming 51 * packets and transmit outgoing ones. 52 */ 53 struct l2tp_session_cfg { 54 enum l2tp_pwtype pw_type; 55 unsigned int recv_seq:1; /* expect receive packets with 56 * sequence numbers? */ 57 unsigned int send_seq:1; /* send packets with sequence 58 * numbers? */ 59 unsigned int lns_mode:1; /* behave as LNS? LAC enables 60 * sequence numbers under 61 * control of LNS. */ 62 int debug; /* bitmask of debug message 63 * categories */ 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 */ 69 int reorder_timeout; /* configured reorder timeout 70 * (in jiffies) */ 71 char *ifname; 72 }; 73 74 struct 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 recv_seq:1; /* expect receive packets with 103 * sequence numbers? */ 104 unsigned int send_seq:1; /* send packets with sequence 105 * numbers? */ 106 unsigned int lns_mode:1; /* behave as LNS? LAC enables 107 * sequence numbers under 108 * control of LNS. */ 109 int debug; /* bitmask of debug message 110 * categories */ 111 int reorder_timeout; /* configured reorder timeout 112 * (in jiffies) */ 113 int reorder_skip; /* set if skip to next nr */ 114 enum l2tp_pwtype pwtype; 115 struct l2tp_stats stats; 116 struct hlist_node global_hlist; /* Global hash list node */ 117 118 int (*build_header)(struct l2tp_session *session, void *buf); 119 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 120 void (*session_close)(struct l2tp_session *session); 121 void (*show)(struct seq_file *m, void *priv); 122 uint8_t priv[0]; /* private data */ 123 }; 124 125 /* Describes the tunnel. It contains info to track all the associated 126 * sessions so incoming packets can be sorted out 127 */ 128 struct l2tp_tunnel_cfg { 129 int debug; /* bitmask of debug message 130 * categories */ 131 enum l2tp_encap_type encap; 132 133 /* Used only for kernel-created sockets */ 134 struct in_addr local_ip; 135 struct in_addr peer_ip; 136 #if IS_ENABLED(CONFIG_IPV6) 137 struct in6_addr *local_ip6; 138 struct in6_addr *peer_ip6; 139 #endif 140 u16 local_udp_port; 141 u16 peer_udp_port; 142 unsigned int use_udp_checksums:1, 143 udp6_zero_tx_checksums:1, 144 udp6_zero_rx_checksums:1; 145 }; 146 147 struct l2tp_tunnel { 148 int magic; /* Should be L2TP_TUNNEL_MAGIC */ 149 150 unsigned long dead; 151 152 struct rcu_head rcu; 153 rwlock_t hlist_lock; /* protect session_hlist */ 154 bool acpt_newsess; /* Indicates whether this 155 * tunnel accepts new sessions. 156 * Protected by hlist_lock. 157 */ 158 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 159 /* hashed list of sessions, 160 * hashed by id */ 161 u32 tunnel_id; 162 u32 peer_tunnel_id; 163 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 164 165 char name[20]; /* for logging */ 166 int debug; /* bitmask of debug message 167 * categories */ 168 enum l2tp_encap_type encap; 169 struct l2tp_stats stats; 170 171 struct list_head list; /* Keep a list of all tunnels */ 172 struct net *l2tp_net; /* the net we belong to */ 173 174 refcount_t ref_count; 175 void (*old_sk_destruct)(struct sock *); 176 struct sock *sock; /* Parent socket */ 177 int fd; /* Parent fd, if tunnel socket 178 * was created by userspace */ 179 180 struct work_struct del_work; 181 }; 182 183 struct l2tp_nl_cmd_ops { 184 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel, 185 u32 session_id, u32 peer_session_id, 186 struct l2tp_session_cfg *cfg); 187 int (*session_delete)(struct l2tp_session *session); 188 }; 189 190 static inline void *l2tp_session_priv(struct l2tp_session *session) 191 { 192 return &session->priv[0]; 193 } 194 195 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id); 196 struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth); 197 struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel, 198 u32 session_id); 199 200 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); 201 202 struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id); 203 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth); 204 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, 205 const char *ifname); 206 207 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, 208 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, 209 struct l2tp_tunnel **tunnelp); 210 int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, 211 struct l2tp_tunnel_cfg *cfg); 212 213 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 214 struct l2tp_session *l2tp_session_create(int priv_size, 215 struct l2tp_tunnel *tunnel, 216 u32 session_id, u32 peer_session_id, 217 struct l2tp_session_cfg *cfg); 218 int l2tp_session_register(struct l2tp_session *session, 219 struct l2tp_tunnel *tunnel); 220 221 void __l2tp_session_unhash(struct l2tp_session *session); 222 int l2tp_session_delete(struct l2tp_session *session); 223 void l2tp_session_free(struct l2tp_session *session); 224 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 225 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 226 int length); 227 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 228 void l2tp_session_set_header_len(struct l2tp_session *session, int version); 229 230 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, 231 int hdr_len); 232 233 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, 234 const struct l2tp_nl_cmd_ops *ops); 235 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 236 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); 237 238 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel) 239 { 240 refcount_inc(&tunnel->ref_count); 241 } 242 243 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) 244 { 245 if (refcount_dec_and_test(&tunnel->ref_count)) 246 l2tp_tunnel_free(tunnel); 247 } 248 249 /* Session reference counts. Incremented when code obtains a reference 250 * to a session. 251 */ 252 static inline void l2tp_session_inc_refcount(struct l2tp_session *session) 253 { 254 refcount_inc(&session->ref_count); 255 } 256 257 static inline void l2tp_session_dec_refcount(struct l2tp_session *session) 258 { 259 if (refcount_dec_and_test(&session->ref_count)) 260 l2tp_session_free(session); 261 } 262 263 static inline int l2tp_get_l2specific_len(struct l2tp_session *session) 264 { 265 switch (session->l2specific_type) { 266 case L2TP_L2SPECTYPE_DEFAULT: 267 return 4; 268 case L2TP_L2SPECTYPE_NONE: 269 default: 270 return 0; 271 } 272 } 273 274 static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel) 275 { 276 struct dst_entry *dst; 277 u32 mtu; 278 279 dst = sk_dst_get(tunnel->sock); 280 if (!dst) 281 return 0; 282 283 mtu = dst_mtu(dst); 284 dst_release(dst); 285 286 return mtu; 287 } 288 289 #ifdef CONFIG_XFRM 290 static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel) 291 { 292 struct sock *sk = tunnel->sock; 293 294 return sk && (rcu_access_pointer(sk->sk_policy[0]) || 295 rcu_access_pointer(sk->sk_policy[1])); 296 } 297 #else 298 static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel) 299 { 300 return false; 301 } 302 #endif 303 304 static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb, 305 unsigned char **ptr, unsigned char **optr) 306 { 307 int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session); 308 309 if (opt_len > 0) { 310 int off = *ptr - *optr; 311 312 if (!pskb_may_pull(skb, off + opt_len)) 313 return -1; 314 315 if (skb->data != *optr) { 316 *optr = skb->data; 317 *ptr = skb->data + off; 318 } 319 } 320 321 return 0; 322 } 323 324 #define l2tp_printk(ptr, type, func, fmt, ...) \ 325 do { \ 326 if (((ptr)->debug) & (type)) \ 327 func(fmt, ##__VA_ARGS__); \ 328 } while (0) 329 330 #define l2tp_warn(ptr, type, fmt, ...) \ 331 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 332 #define l2tp_info(ptr, type, fmt, ...) \ 333 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 334 #define l2tp_dbg(ptr, type, fmt, ...) \ 335 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 336 337 #define MODULE_ALIAS_L2TP_PWTYPE(type) \ 338 MODULE_ALIAS("net-l2tp-type-" __stringify(type)) 339 340 #endif /* _L2TP_CORE_H_ */ 341