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 /* Just some random numbers */ 19 #define L2TP_TUNNEL_MAGIC 0x42114DDA 20 #define L2TP_SESSION_MAGIC 0x0C04EB7D 21 22 /* Per tunnel, session hash table size */ 23 #define L2TP_HASH_BITS 4 24 #define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS) 25 26 /* System-wide, session hash table size */ 27 #define L2TP_HASH_BITS_2 8 28 #define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2) 29 30 struct sk_buff; 31 32 struct l2tp_stats { 33 atomic_long_t tx_packets; 34 atomic_long_t tx_bytes; 35 atomic_long_t tx_errors; 36 atomic_long_t rx_packets; 37 atomic_long_t rx_bytes; 38 atomic_long_t rx_seq_discards; 39 atomic_long_t rx_oos_packets; 40 atomic_long_t rx_errors; 41 atomic_long_t rx_cookie_discards; 42 }; 43 44 struct l2tp_tunnel; 45 46 /* Describes a session. Contains information to determine incoming 47 * packets and transmit outgoing ones. 48 */ 49 struct l2tp_session_cfg { 50 enum l2tp_pwtype pw_type; 51 unsigned int recv_seq:1; /* expect receive packets with 52 * sequence numbers? */ 53 unsigned int send_seq:1; /* send packets with sequence 54 * numbers? */ 55 unsigned int lns_mode:1; /* behave as LNS? LAC enables 56 * sequence numbers under 57 * control of LNS. */ 58 int debug; /* bitmask of debug message 59 * categories */ 60 u16 l2specific_type; /* Layer 2 specific type */ 61 u8 cookie[8]; /* optional cookie */ 62 int cookie_len; /* 0, 4 or 8 bytes */ 63 u8 peer_cookie[8]; /* peer's cookie */ 64 int peer_cookie_len; /* 0, 4 or 8 bytes */ 65 int reorder_timeout; /* configured reorder timeout 66 * (in jiffies) */ 67 char *ifname; 68 }; 69 70 struct l2tp_session { 71 int magic; /* should be 72 * L2TP_SESSION_MAGIC */ 73 long dead; 74 75 struct l2tp_tunnel *tunnel; /* back pointer to tunnel 76 * context */ 77 u32 session_id; 78 u32 peer_session_id; 79 u8 cookie[8]; 80 int cookie_len; 81 u8 peer_cookie[8]; 82 int peer_cookie_len; 83 u16 l2specific_type; 84 u16 hdr_len; 85 u32 nr; /* session NR state (receive) */ 86 u32 ns; /* session NR state (send) */ 87 struct sk_buff_head reorder_q; /* receive reorder queue */ 88 u32 nr_max; /* max NR. Depends on tunnel */ 89 u32 nr_window_size; /* NR window size */ 90 u32 nr_oos; /* NR of last OOS packet */ 91 int nr_oos_count; /* For OOS recovery */ 92 int nr_oos_count_max; 93 struct hlist_node hlist; /* Hash list node */ 94 refcount_t ref_count; 95 96 char name[32]; /* for logging */ 97 char ifname[IFNAMSIZ]; 98 unsigned int recv_seq:1; /* expect receive packets with 99 * sequence numbers? */ 100 unsigned int send_seq:1; /* send packets with sequence 101 * numbers? */ 102 unsigned int lns_mode:1; /* behave as LNS? LAC enables 103 * sequence numbers under 104 * control of LNS. */ 105 int debug; /* bitmask of debug message 106 * categories */ 107 int reorder_timeout; /* configured reorder timeout 108 * (in jiffies) */ 109 int reorder_skip; /* set if skip to next nr */ 110 enum l2tp_pwtype pwtype; 111 struct l2tp_stats stats; 112 struct hlist_node global_hlist; /* Global hash list node */ 113 114 int (*build_header)(struct l2tp_session *session, void *buf); 115 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 116 void (*session_close)(struct l2tp_session *session); 117 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) 118 void (*show)(struct seq_file *m, void *priv); 119 #endif 120 uint8_t priv[0]; /* private data */ 121 }; 122 123 /* Describes the tunnel. It contains info to track all the associated 124 * sessions so incoming packets can be sorted out 125 */ 126 struct l2tp_tunnel_cfg { 127 int debug; /* bitmask of debug message 128 * categories */ 129 enum l2tp_encap_type encap; 130 131 /* Used only for kernel-created sockets */ 132 struct in_addr local_ip; 133 struct in_addr peer_ip; 134 #if IS_ENABLED(CONFIG_IPV6) 135 struct in6_addr *local_ip6; 136 struct in6_addr *peer_ip6; 137 #endif 138 u16 local_udp_port; 139 u16 peer_udp_port; 140 unsigned int use_udp_checksums:1, 141 udp6_zero_tx_checksums:1, 142 udp6_zero_rx_checksums:1; 143 }; 144 145 struct l2tp_tunnel { 146 int magic; /* Should be L2TP_TUNNEL_MAGIC */ 147 148 unsigned long dead; 149 150 struct rcu_head rcu; 151 rwlock_t hlist_lock; /* protect session_hlist */ 152 bool acpt_newsess; /* Indicates whether this 153 * tunnel accepts new sessions. 154 * Protected by hlist_lock. 155 */ 156 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 157 /* hashed list of sessions, 158 * hashed by id */ 159 u32 tunnel_id; 160 u32 peer_tunnel_id; 161 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 162 163 char name[20]; /* for logging */ 164 int debug; /* bitmask of debug message 165 * categories */ 166 enum l2tp_encap_type encap; 167 struct l2tp_stats stats; 168 169 struct list_head list; /* Keep a list of all tunnels */ 170 struct net *l2tp_net; /* the net we belong to */ 171 172 refcount_t ref_count; 173 void (*old_sk_destruct)(struct sock *); 174 struct sock *sock; /* Parent socket */ 175 int fd; /* Parent fd, if tunnel socket 176 * was created by userspace */ 177 178 struct work_struct del_work; 179 }; 180 181 struct l2tp_nl_cmd_ops { 182 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel, 183 u32 session_id, u32 peer_session_id, 184 struct l2tp_session_cfg *cfg); 185 int (*session_delete)(struct l2tp_session *session); 186 }; 187 188 static inline void *l2tp_session_priv(struct l2tp_session *session) 189 { 190 return &session->priv[0]; 191 } 192 193 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id); 194 struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth); 195 196 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); 197 198 struct l2tp_session *l2tp_session_get(const struct net *net, 199 struct l2tp_tunnel *tunnel, 200 u32 session_id); 201 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth); 202 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, 203 const char *ifname); 204 205 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, 206 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, 207 struct l2tp_tunnel **tunnelp); 208 int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, 209 struct l2tp_tunnel_cfg *cfg); 210 211 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 212 struct l2tp_session *l2tp_session_create(int priv_size, 213 struct l2tp_tunnel *tunnel, 214 u32 session_id, u32 peer_session_id, 215 struct l2tp_session_cfg *cfg); 216 int l2tp_session_register(struct l2tp_session *session, 217 struct l2tp_tunnel *tunnel); 218 219 void __l2tp_session_unhash(struct l2tp_session *session); 220 int l2tp_session_delete(struct l2tp_session *session); 221 void l2tp_session_free(struct l2tp_session *session); 222 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 223 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 224 int length); 225 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 226 void l2tp_session_set_header_len(struct l2tp_session *session, int version); 227 228 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, 229 int hdr_len); 230 231 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, 232 const struct l2tp_nl_cmd_ops *ops); 233 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 234 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); 235 236 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel) 237 { 238 refcount_inc(&tunnel->ref_count); 239 } 240 241 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) 242 { 243 if (refcount_dec_and_test(&tunnel->ref_count)) 244 l2tp_tunnel_free(tunnel); 245 } 246 247 /* Session reference counts. Incremented when code obtains a reference 248 * to a session. 249 */ 250 static inline void l2tp_session_inc_refcount(struct l2tp_session *session) 251 { 252 refcount_inc(&session->ref_count); 253 } 254 255 static inline void l2tp_session_dec_refcount(struct l2tp_session *session) 256 { 257 if (refcount_dec_and_test(&session->ref_count)) 258 l2tp_session_free(session); 259 } 260 261 static inline int l2tp_get_l2specific_len(struct l2tp_session *session) 262 { 263 switch (session->l2specific_type) { 264 case L2TP_L2SPECTYPE_DEFAULT: 265 return 4; 266 case L2TP_L2SPECTYPE_NONE: 267 default: 268 return 0; 269 } 270 } 271 272 static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel) 273 { 274 struct dst_entry *dst; 275 u32 mtu; 276 277 dst = sk_dst_get(tunnel->sock); 278 if (!dst) 279 return 0; 280 281 mtu = dst_mtu(dst); 282 dst_release(dst); 283 284 return mtu; 285 } 286 287 #define l2tp_printk(ptr, type, func, fmt, ...) \ 288 do { \ 289 if (((ptr)->debug) & (type)) \ 290 func(fmt, ##__VA_ARGS__); \ 291 } while (0) 292 293 #define l2tp_warn(ptr, type, fmt, ...) \ 294 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 295 #define l2tp_info(ptr, type, fmt, ...) \ 296 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 297 #define l2tp_dbg(ptr, type, fmt, ...) \ 298 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 299 300 #define MODULE_ALIAS_L2TP_PWTYPE(type) \ 301 MODULE_ALIAS("net-l2tp-type-" __stringify(type)) 302 303 #endif /* _L2TP_CORE_H_ */ 304