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 27 struct sk_buff; 28 29 struct 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 41 struct l2tp_tunnel; 42 43 /* Describes a session. Contains information to determine incoming 44 * packets and transmit outgoing ones. 45 */ 46 struct 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 offset; /* offset to tx payload */ 63 u16 peer_offset; /* offset to rx payload */ 64 u16 l2specific_len; /* Layer 2 specific length */ 65 u16 l2specific_type; /* Layer 2 specific type */ 66 u8 cookie[8]; /* optional cookie */ 67 int cookie_len; /* 0, 4 or 8 bytes */ 68 u8 peer_cookie[8]; /* peer's cookie */ 69 int peer_cookie_len; /* 0, 4 or 8 bytes */ 70 int reorder_timeout; /* configured reorder timeout 71 * (in jiffies) */ 72 int mtu; 73 int mru; 74 char *ifname; 75 }; 76 77 struct l2tp_session { 78 int magic; /* should be 79 * L2TP_SESSION_MAGIC */ 80 long dead; 81 82 struct l2tp_tunnel *tunnel; /* back pointer to tunnel 83 * context */ 84 u32 session_id; 85 u32 peer_session_id; 86 u8 cookie[8]; 87 int cookie_len; 88 u8 peer_cookie[8]; 89 int peer_cookie_len; 90 u16 offset; /* offset from end of L2TP 91 * header to beginning of 92 * tx data 93 */ 94 u16 peer_offset; /* offset from end of L2TP 95 * header to beginning of 96 * rx data 97 */ 98 u16 l2specific_len; 99 u16 l2specific_type; 100 u16 hdr_len; 101 u32 nr; /* session NR state (receive) */ 102 u32 ns; /* session NR state (send) */ 103 struct sk_buff_head reorder_q; /* receive reorder queue */ 104 u32 nr_max; /* max NR. Depends on tunnel */ 105 u32 nr_window_size; /* NR window size */ 106 u32 nr_oos; /* NR of last OOS packet */ 107 int nr_oos_count; /* For OOS recovery */ 108 int nr_oos_count_max; 109 struct hlist_node hlist; /* Hash list node */ 110 refcount_t ref_count; 111 112 char name[32]; /* for logging */ 113 char ifname[IFNAMSIZ]; 114 unsigned int data_seq:2; /* data sequencing level 115 * 0 => none, 1 => IP only, 116 * 2 => all 117 */ 118 unsigned int recv_seq:1; /* expect receive packets with 119 * sequence numbers? */ 120 unsigned int send_seq:1; /* send packets with sequence 121 * numbers? */ 122 unsigned int lns_mode:1; /* behave as LNS? LAC enables 123 * sequence numbers under 124 * control of LNS. */ 125 int debug; /* bitmask of debug message 126 * categories */ 127 int reorder_timeout; /* configured reorder timeout 128 * (in jiffies) */ 129 int reorder_skip; /* set if skip to next nr */ 130 int mtu; 131 int mru; 132 enum l2tp_pwtype pwtype; 133 struct l2tp_stats stats; 134 struct hlist_node global_hlist; /* Global hash list node */ 135 136 int (*build_header)(struct l2tp_session *session, void *buf); 137 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 138 void (*session_close)(struct l2tp_session *session); 139 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) 140 void (*show)(struct seq_file *m, void *priv); 141 #endif 142 uint8_t priv[0]; /* private data */ 143 }; 144 145 /* Describes the tunnel. It contains info to track all the associated 146 * sessions so incoming packets can be sorted out 147 */ 148 struct l2tp_tunnel_cfg { 149 int debug; /* bitmask of debug message 150 * categories */ 151 enum l2tp_encap_type encap; 152 153 /* Used only for kernel-created sockets */ 154 struct in_addr local_ip; 155 struct in_addr peer_ip; 156 #if IS_ENABLED(CONFIG_IPV6) 157 struct in6_addr *local_ip6; 158 struct in6_addr *peer_ip6; 159 #endif 160 u16 local_udp_port; 161 u16 peer_udp_port; 162 unsigned int use_udp_checksums:1, 163 udp6_zero_tx_checksums:1, 164 udp6_zero_rx_checksums:1; 165 }; 166 167 struct l2tp_tunnel { 168 int magic; /* Should be L2TP_TUNNEL_MAGIC */ 169 170 unsigned long dead; 171 172 struct rcu_head rcu; 173 rwlock_t hlist_lock; /* protect session_hlist */ 174 bool acpt_newsess; /* Indicates whether this 175 * tunnel accepts new sessions. 176 * Protected by hlist_lock. 177 */ 178 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 179 /* hashed list of sessions, 180 * hashed by id */ 181 u32 tunnel_id; 182 u32 peer_tunnel_id; 183 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 184 185 char name[20]; /* for logging */ 186 int debug; /* bitmask of debug message 187 * categories */ 188 enum l2tp_encap_type encap; 189 struct l2tp_stats stats; 190 191 struct list_head list; /* Keep a list of all tunnels */ 192 struct net *l2tp_net; /* the net we belong to */ 193 194 refcount_t ref_count; 195 #ifdef CONFIG_DEBUG_FS 196 void (*show)(struct seq_file *m, void *arg); 197 #endif 198 int (*recv_payload_hook)(struct sk_buff *skb); 199 void (*old_sk_destruct)(struct sock *); 200 struct sock *sock; /* Parent socket */ 201 int fd; /* Parent fd, if tunnel socket 202 * was created by userspace */ 203 #if IS_ENABLED(CONFIG_IPV6) 204 bool v4mapped; 205 #endif 206 207 struct work_struct del_work; 208 209 uint8_t priv[0]; /* private data */ 210 }; 211 212 struct l2tp_nl_cmd_ops { 213 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel, 214 u32 session_id, u32 peer_session_id, 215 struct l2tp_session_cfg *cfg); 216 int (*session_delete)(struct l2tp_session *session); 217 }; 218 219 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel) 220 { 221 return &tunnel->priv[0]; 222 } 223 224 static inline void *l2tp_session_priv(struct l2tp_session *session) 225 { 226 return &session->priv[0]; 227 } 228 229 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk) 230 { 231 struct l2tp_tunnel *tunnel; 232 233 if (sk == NULL) 234 return NULL; 235 236 sock_hold(sk); 237 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data); 238 if (tunnel == NULL) { 239 sock_put(sk); 240 goto out; 241 } 242 243 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 244 245 out: 246 return tunnel; 247 } 248 249 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id); 250 251 struct l2tp_session *l2tp_session_get(const struct net *net, 252 struct l2tp_tunnel *tunnel, 253 u32 session_id); 254 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth); 255 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, 256 const char *ifname); 257 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id); 258 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth); 259 260 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, 261 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, 262 struct l2tp_tunnel **tunnelp); 263 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); 264 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 265 struct l2tp_session *l2tp_session_create(int priv_size, 266 struct l2tp_tunnel *tunnel, 267 u32 session_id, u32 peer_session_id, 268 struct l2tp_session_cfg *cfg); 269 int l2tp_session_register(struct l2tp_session *session, 270 struct l2tp_tunnel *tunnel); 271 272 void __l2tp_session_unhash(struct l2tp_session *session); 273 int l2tp_session_delete(struct l2tp_session *session); 274 void l2tp_session_free(struct l2tp_session *session); 275 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 276 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 277 int length, int (*payload_hook)(struct sk_buff *skb)); 278 int l2tp_session_queue_purge(struct l2tp_session *session); 279 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 280 void l2tp_session_set_header_len(struct l2tp_session *session, int version); 281 282 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, 283 int hdr_len); 284 285 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, 286 const struct l2tp_nl_cmd_ops *ops); 287 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 288 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); 289 290 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel) 291 { 292 refcount_inc(&tunnel->ref_count); 293 } 294 295 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) 296 { 297 if (refcount_dec_and_test(&tunnel->ref_count)) 298 kfree_rcu(tunnel, rcu); 299 } 300 301 /* Session reference counts. Incremented when code obtains a reference 302 * to a session. 303 */ 304 static inline void l2tp_session_inc_refcount(struct l2tp_session *session) 305 { 306 refcount_inc(&session->ref_count); 307 } 308 309 static inline void l2tp_session_dec_refcount(struct l2tp_session *session) 310 { 311 if (refcount_dec_and_test(&session->ref_count)) 312 l2tp_session_free(session); 313 } 314 315 #define l2tp_printk(ptr, type, func, fmt, ...) \ 316 do { \ 317 if (((ptr)->debug) & (type)) \ 318 func(fmt, ##__VA_ARGS__); \ 319 } while (0) 320 321 #define l2tp_warn(ptr, type, fmt, ...) \ 322 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 323 #define l2tp_info(ptr, type, fmt, ...) \ 324 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 325 #define l2tp_dbg(ptr, type, fmt, ...) \ 326 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 327 328 #define MODULE_ALIAS_L2TP_PWTYPE(type) \ 329 MODULE_ALIAS("net-l2tp-type-" __stringify(type)) 330 331 #endif /* _L2TP_CORE_H_ */ 332