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 11 #ifndef _L2TP_CORE_H_ 12 #define _L2TP_CORE_H_ 13 14 /* Just some random numbers */ 15 #define L2TP_TUNNEL_MAGIC 0x42114DDA 16 #define L2TP_SESSION_MAGIC 0x0C04EB7D 17 18 /* Per tunnel, session hash table size */ 19 #define L2TP_HASH_BITS 4 20 #define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS) 21 22 /* System-wide, session hash table size */ 23 #define L2TP_HASH_BITS_2 8 24 #define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2) 25 26 /* Debug message categories for the DEBUG socket option */ 27 enum { 28 L2TP_MSG_DEBUG = (1 << 0), /* verbose debug (if 29 * compiled in) */ 30 L2TP_MSG_CONTROL = (1 << 1), /* userspace - kernel 31 * interface */ 32 L2TP_MSG_SEQ = (1 << 2), /* sequence numbers */ 33 L2TP_MSG_DATA = (1 << 3), /* data packets */ 34 }; 35 36 struct sk_buff; 37 38 struct l2tp_stats { 39 atomic_long_t tx_packets; 40 atomic_long_t tx_bytes; 41 atomic_long_t tx_errors; 42 atomic_long_t rx_packets; 43 atomic_long_t rx_bytes; 44 atomic_long_t rx_seq_discards; 45 atomic_long_t rx_oos_packets; 46 atomic_long_t rx_errors; 47 atomic_long_t rx_cookie_discards; 48 }; 49 50 struct l2tp_tunnel; 51 52 /* Describes a session. Contains information to determine incoming 53 * packets and transmit outgoing ones. 54 */ 55 struct l2tp_session_cfg { 56 enum l2tp_pwtype pw_type; 57 unsigned int data_seq:2; /* data sequencing level 58 * 0 => none, 1 => IP only, 59 * 2 => all 60 */ 61 unsigned int recv_seq:1; /* expect receive packets with 62 * sequence numbers? */ 63 unsigned int send_seq:1; /* send packets with sequence 64 * numbers? */ 65 unsigned int lns_mode:1; /* behave as LNS? LAC enables 66 * sequence numbers under 67 * control of LNS. */ 68 int debug; /* bitmask of debug message 69 * categories */ 70 u16 vlan_id; /* VLAN pseudowire only */ 71 u16 offset; /* offset to payload */ 72 u16 l2specific_len; /* Layer 2 specific length */ 73 u16 l2specific_type; /* Layer 2 specific type */ 74 u8 cookie[8]; /* optional cookie */ 75 int cookie_len; /* 0, 4 or 8 bytes */ 76 u8 peer_cookie[8]; /* peer's cookie */ 77 int peer_cookie_len; /* 0, 4 or 8 bytes */ 78 int reorder_timeout; /* configured reorder timeout 79 * (in jiffies) */ 80 int mtu; 81 int mru; 82 char *ifname; 83 }; 84 85 struct l2tp_session { 86 int magic; /* should be 87 * L2TP_SESSION_MAGIC */ 88 89 struct l2tp_tunnel *tunnel; /* back pointer to tunnel 90 * context */ 91 u32 session_id; 92 u32 peer_session_id; 93 u8 cookie[8]; 94 int cookie_len; 95 u8 peer_cookie[8]; 96 int peer_cookie_len; 97 u16 offset; /* offset from end of L2TP header 98 to beginning of data */ 99 u16 l2specific_len; 100 u16 l2specific_type; 101 u16 hdr_len; 102 u32 nr; /* session NR state (receive) */ 103 u32 ns; /* session NR state (send) */ 104 struct sk_buff_head reorder_q; /* receive reorder queue */ 105 u32 nr_max; /* max NR. Depends on tunnel */ 106 u32 nr_window_size; /* NR window size */ 107 u32 nr_oos; /* NR of last OOS packet */ 108 int nr_oos_count; /* For OOS recovery */ 109 int nr_oos_count_max; 110 struct hlist_node hlist; /* Hash list node */ 111 atomic_t ref_count; 112 113 char name[32]; /* for logging */ 114 char ifname[IFNAMSIZ]; 115 unsigned int data_seq:2; /* data sequencing level 116 * 0 => none, 1 => IP only, 117 * 2 => all 118 */ 119 unsigned int recv_seq:1; /* expect receive packets with 120 * sequence numbers? */ 121 unsigned int send_seq:1; /* send packets with sequence 122 * numbers? */ 123 unsigned int lns_mode:1; /* behave as LNS? LAC enables 124 * sequence numbers under 125 * control of LNS. */ 126 int debug; /* bitmask of debug message 127 * categories */ 128 int reorder_timeout; /* configured reorder timeout 129 * (in jiffies) */ 130 int reorder_skip; /* set if skip to next nr */ 131 int mtu; 132 int mru; 133 enum l2tp_pwtype pwtype; 134 struct l2tp_stats stats; 135 struct hlist_node global_hlist; /* Global hash list node */ 136 137 int (*build_header)(struct l2tp_session *session, void *buf); 138 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 139 void (*session_close)(struct l2tp_session *session); 140 void (*ref)(struct l2tp_session *session); 141 void (*deref)(struct l2tp_session *session); 142 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE) 143 void (*show)(struct seq_file *m, void *priv); 144 #endif 145 uint8_t priv[0]; /* private data */ 146 }; 147 148 /* Describes the tunnel. It contains info to track all the associated 149 * sessions so incoming packets can be sorted out 150 */ 151 struct l2tp_tunnel_cfg { 152 int debug; /* bitmask of debug message 153 * categories */ 154 enum l2tp_encap_type encap; 155 156 /* Used only for kernel-created sockets */ 157 struct in_addr local_ip; 158 struct in_addr peer_ip; 159 #if IS_ENABLED(CONFIG_IPV6) 160 struct in6_addr *local_ip6; 161 struct in6_addr *peer_ip6; 162 #endif 163 u16 local_udp_port; 164 u16 peer_udp_port; 165 unsigned int use_udp_checksums:1, 166 udp6_zero_tx_checksums:1, 167 udp6_zero_rx_checksums:1; 168 }; 169 170 struct l2tp_tunnel { 171 int magic; /* Should be L2TP_TUNNEL_MAGIC */ 172 struct rcu_head rcu; 173 rwlock_t hlist_lock; /* protect session_hlist */ 174 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 175 /* hashed list of sessions, 176 * hashed by id */ 177 u32 tunnel_id; 178 u32 peer_tunnel_id; 179 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 180 181 char name[20]; /* for logging */ 182 int debug; /* bitmask of debug message 183 * categories */ 184 enum l2tp_encap_type encap; 185 struct l2tp_stats stats; 186 187 struct list_head list; /* Keep a list of all tunnels */ 188 struct net *l2tp_net; /* the net we belong to */ 189 190 atomic_t ref_count; 191 #ifdef CONFIG_DEBUG_FS 192 void (*show)(struct seq_file *m, void *arg); 193 #endif 194 int (*recv_payload_hook)(struct sk_buff *skb); 195 void (*old_sk_destruct)(struct sock *); 196 struct sock *sock; /* Parent socket */ 197 int fd; /* Parent fd, if tunnel socket 198 * was created by userspace */ 199 #if IS_ENABLED(CONFIG_IPV6) 200 bool v4mapped; 201 #endif 202 203 struct work_struct del_work; 204 205 uint8_t priv[0]; /* private data */ 206 }; 207 208 struct l2tp_nl_cmd_ops { 209 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg); 210 int (*session_delete)(struct l2tp_session *session); 211 }; 212 213 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel) 214 { 215 return &tunnel->priv[0]; 216 } 217 218 static inline void *l2tp_session_priv(struct l2tp_session *session) 219 { 220 return &session->priv[0]; 221 } 222 223 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk) 224 { 225 struct l2tp_tunnel *tunnel; 226 227 if (sk == NULL) 228 return NULL; 229 230 sock_hold(sk); 231 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data); 232 if (tunnel == NULL) { 233 sock_put(sk); 234 goto out; 235 } 236 237 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 238 239 out: 240 return tunnel; 241 } 242 243 struct l2tp_session *l2tp_session_find(struct net *net, 244 struct l2tp_tunnel *tunnel, 245 u32 session_id); 246 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth); 247 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname); 248 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id); 249 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth); 250 251 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, 252 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, 253 struct l2tp_tunnel **tunnelp); 254 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); 255 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 256 struct l2tp_session *l2tp_session_create(int priv_size, 257 struct l2tp_tunnel *tunnel, 258 u32 session_id, u32 peer_session_id, 259 struct l2tp_session_cfg *cfg); 260 void __l2tp_session_unhash(struct l2tp_session *session); 261 int l2tp_session_delete(struct l2tp_session *session); 262 void l2tp_session_free(struct l2tp_session *session); 263 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 264 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 265 int length, int (*payload_hook)(struct sk_buff *skb)); 266 int l2tp_session_queue_purge(struct l2tp_session *session); 267 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 268 void l2tp_session_set_header_len(struct l2tp_session *session, int version); 269 270 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, 271 int hdr_len); 272 273 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, 274 const struct l2tp_nl_cmd_ops *ops); 275 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 276 277 /* Session reference counts. Incremented when code obtains a reference 278 * to a session. 279 */ 280 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session) 281 { 282 atomic_inc(&session->ref_count); 283 } 284 285 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session) 286 { 287 if (atomic_dec_and_test(&session->ref_count)) 288 l2tp_session_free(session); 289 } 290 291 #ifdef L2TP_REFCNT_DEBUG 292 #define l2tp_session_inc_refcount(_s) \ 293 do { \ 294 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \ 295 __func__, __LINE__, (_s)->name, \ 296 atomic_read(&_s->ref_count)); \ 297 l2tp_session_inc_refcount_1(_s); \ 298 } while (0) 299 #define l2tp_session_dec_refcount(_s) \ 300 do { \ 301 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \ 302 __func__, __LINE__, (_s)->name, \ 303 atomic_read(&_s->ref_count)); \ 304 l2tp_session_dec_refcount_1(_s); \ 305 } while (0) 306 #else 307 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s) 308 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s) 309 #endif 310 311 #define l2tp_printk(ptr, type, func, fmt, ...) \ 312 do { \ 313 if (((ptr)->debug) & (type)) \ 314 func(fmt, ##__VA_ARGS__); \ 315 } while (0) 316 317 #define l2tp_warn(ptr, type, fmt, ...) \ 318 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 319 #define l2tp_info(ptr, type, fmt, ...) \ 320 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 321 #define l2tp_dbg(ptr, type, fmt, ...) \ 322 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 323 324 #define MODULE_ALIAS_L2TP_PWTYPE(type) \ 325 MODULE_ALIAS("net-l2tp-type-" __stringify(type)) 326 327 #endif /* _L2TP_CORE_H_ */ 328