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