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