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_type; /* Layer 2 specific type */ 63 u8 cookie[8]; /* optional cookie */ 64 int cookie_len; /* 0, 4 or 8 bytes */ 65 u8 peer_cookie[8]; /* peer's cookie */ 66 int peer_cookie_len; /* 0, 4 or 8 bytes */ 67 int reorder_timeout; /* configured reorder timeout 68 * (in jiffies) */ 69 int mtu; 70 int mru; 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 data_seq:2; /* data sequencing level 103 * 0 => none, 1 => IP only, 104 * 2 => all 105 */ 106 unsigned int recv_seq:1; /* expect receive packets with 107 * sequence numbers? */ 108 unsigned int send_seq:1; /* send packets with sequence 109 * numbers? */ 110 unsigned int lns_mode:1; /* behave as LNS? LAC enables 111 * sequence numbers under 112 * control of LNS. */ 113 int debug; /* bitmask of debug message 114 * categories */ 115 int reorder_timeout; /* configured reorder timeout 116 * (in jiffies) */ 117 int reorder_skip; /* set if skip to next nr */ 118 int mtu; 119 int mru; 120 enum l2tp_pwtype pwtype; 121 struct l2tp_stats stats; 122 struct hlist_node global_hlist; /* Global hash list node */ 123 124 int (*build_header)(struct l2tp_session *session, void *buf); 125 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 126 void (*session_close)(struct l2tp_session *session); 127 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) 128 void (*show)(struct seq_file *m, void *priv); 129 #endif 130 uint8_t priv[0]; /* private data */ 131 }; 132 133 /* Describes the tunnel. It contains info to track all the associated 134 * sessions so incoming packets can be sorted out 135 */ 136 struct l2tp_tunnel_cfg { 137 int debug; /* bitmask of debug message 138 * categories */ 139 enum l2tp_encap_type encap; 140 141 /* Used only for kernel-created sockets */ 142 struct in_addr local_ip; 143 struct in_addr peer_ip; 144 #if IS_ENABLED(CONFIG_IPV6) 145 struct in6_addr *local_ip6; 146 struct in6_addr *peer_ip6; 147 #endif 148 u16 local_udp_port; 149 u16 peer_udp_port; 150 unsigned int use_udp_checksums:1, 151 udp6_zero_tx_checksums:1, 152 udp6_zero_rx_checksums:1; 153 }; 154 155 struct l2tp_tunnel { 156 int magic; /* Should be L2TP_TUNNEL_MAGIC */ 157 158 unsigned long dead; 159 160 struct rcu_head rcu; 161 rwlock_t hlist_lock; /* protect session_hlist */ 162 bool acpt_newsess; /* Indicates whether this 163 * tunnel accepts new sessions. 164 * Protected by hlist_lock. 165 */ 166 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 167 /* hashed list of sessions, 168 * hashed by id */ 169 u32 tunnel_id; 170 u32 peer_tunnel_id; 171 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 172 173 char name[20]; /* for logging */ 174 int debug; /* bitmask of debug message 175 * categories */ 176 enum l2tp_encap_type encap; 177 struct l2tp_stats stats; 178 179 struct list_head list; /* Keep a list of all tunnels */ 180 struct net *l2tp_net; /* the net we belong to */ 181 182 refcount_t ref_count; 183 #ifdef CONFIG_DEBUG_FS 184 void (*show)(struct seq_file *m, void *arg); 185 #endif 186 int (*recv_payload_hook)(struct sk_buff *skb); 187 void (*old_sk_destruct)(struct sock *); 188 struct sock *sock; /* Parent socket */ 189 int fd; /* Parent fd, if tunnel socket 190 * was created by userspace */ 191 192 struct work_struct del_work; 193 194 uint8_t priv[0]; /* private data */ 195 }; 196 197 struct l2tp_nl_cmd_ops { 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); 201 int (*session_delete)(struct l2tp_session *session); 202 }; 203 204 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel) 205 { 206 return &tunnel->priv[0]; 207 } 208 209 static inline void *l2tp_session_priv(struct l2tp_session *session) 210 { 211 return &session->priv[0]; 212 } 213 214 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id); 215 struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth); 216 217 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); 218 219 struct l2tp_session *l2tp_session_get(const struct net *net, 220 struct l2tp_tunnel *tunnel, 221 u32 session_id); 222 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth); 223 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, 224 const char *ifname); 225 226 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, 227 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, 228 struct l2tp_tunnel **tunnelp); 229 int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, 230 struct l2tp_tunnel_cfg *cfg); 231 232 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); 233 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 234 struct l2tp_session *l2tp_session_create(int priv_size, 235 struct l2tp_tunnel *tunnel, 236 u32 session_id, u32 peer_session_id, 237 struct l2tp_session_cfg *cfg); 238 int l2tp_session_register(struct l2tp_session *session, 239 struct l2tp_tunnel *tunnel); 240 241 void __l2tp_session_unhash(struct l2tp_session *session); 242 int l2tp_session_delete(struct l2tp_session *session); 243 void l2tp_session_free(struct l2tp_session *session); 244 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 245 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 246 int length, int (*payload_hook)(struct sk_buff *skb)); 247 int l2tp_session_queue_purge(struct l2tp_session *session); 248 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 249 void l2tp_session_set_header_len(struct l2tp_session *session, int version); 250 251 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, 252 int hdr_len); 253 254 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, 255 const struct l2tp_nl_cmd_ops *ops); 256 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 257 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); 258 259 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel) 260 { 261 refcount_inc(&tunnel->ref_count); 262 } 263 264 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) 265 { 266 if (refcount_dec_and_test(&tunnel->ref_count)) 267 l2tp_tunnel_free(tunnel); 268 } 269 270 /* Session reference counts. Incremented when code obtains a reference 271 * to a session. 272 */ 273 static inline void l2tp_session_inc_refcount(struct l2tp_session *session) 274 { 275 refcount_inc(&session->ref_count); 276 } 277 278 static inline void l2tp_session_dec_refcount(struct l2tp_session *session) 279 { 280 if (refcount_dec_and_test(&session->ref_count)) 281 l2tp_session_free(session); 282 } 283 284 static inline int l2tp_get_l2specific_len(struct l2tp_session *session) 285 { 286 switch (session->l2specific_type) { 287 case L2TP_L2SPECTYPE_DEFAULT: 288 return 4; 289 case L2TP_L2SPECTYPE_NONE: 290 default: 291 return 0; 292 } 293 } 294 295 #define l2tp_printk(ptr, type, func, fmt, ...) \ 296 do { \ 297 if (((ptr)->debug) & (type)) \ 298 func(fmt, ##__VA_ARGS__); \ 299 } while (0) 300 301 #define l2tp_warn(ptr, type, fmt, ...) \ 302 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 303 #define l2tp_info(ptr, type, fmt, ...) \ 304 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 305 #define l2tp_dbg(ptr, type, fmt, ...) \ 306 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 307 308 #define MODULE_ALIAS_L2TP_PWTYPE(type) \ 309 MODULE_ALIAS("net-l2tp-type-" __stringify(type)) 310 311 #endif /* _L2TP_CORE_H_ */ 312