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 struct sk_buff; 27 28 struct l2tp_stats { 29 atomic_long_t tx_packets; 30 atomic_long_t tx_bytes; 31 atomic_long_t tx_errors; 32 atomic_long_t rx_packets; 33 atomic_long_t rx_bytes; 34 atomic_long_t rx_seq_discards; 35 atomic_long_t rx_oos_packets; 36 atomic_long_t rx_errors; 37 atomic_long_t rx_cookie_discards; 38 }; 39 40 struct l2tp_tunnel; 41 42 /* Describes a session. Contains information to determine incoming 43 * packets and transmit outgoing ones. 44 */ 45 struct l2tp_session_cfg { 46 enum l2tp_pwtype pw_type; 47 unsigned int data_seq:2; /* data sequencing level 48 * 0 => none, 1 => IP only, 49 * 2 => all 50 */ 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 vlan_id; /* VLAN pseudowire only */ 61 u16 offset; /* offset to payload */ 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 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 offset; /* offset from end of L2TP header 88 to beginning of data */ 89 u16 l2specific_len; 90 u16 l2specific_type; 91 u16 hdr_len; 92 u32 nr; /* session NR state (receive) */ 93 u32 ns; /* session NR state (send) */ 94 struct sk_buff_head reorder_q; /* receive reorder queue */ 95 u32 nr_max; /* max NR. Depends on tunnel */ 96 u32 nr_window_size; /* NR window size */ 97 u32 nr_oos; /* NR of last OOS packet */ 98 int nr_oos_count; /* For OOS recovery */ 99 int nr_oos_count_max; 100 struct hlist_node hlist; /* Hash list node */ 101 atomic_t ref_count; 102 103 char name[32]; /* for logging */ 104 char ifname[IFNAMSIZ]; 105 unsigned int data_seq:2; /* data sequencing level 106 * 0 => none, 1 => IP only, 107 * 2 => all 108 */ 109 unsigned int recv_seq:1; /* expect receive packets with 110 * sequence numbers? */ 111 unsigned int send_seq:1; /* send packets with sequence 112 * numbers? */ 113 unsigned int lns_mode:1; /* behave as LNS? LAC enables 114 * sequence numbers under 115 * control of LNS. */ 116 int debug; /* bitmask of debug message 117 * categories */ 118 int reorder_timeout; /* configured reorder timeout 119 * (in jiffies) */ 120 int reorder_skip; /* set if skip to next nr */ 121 int mtu; 122 int mru; 123 enum l2tp_pwtype pwtype; 124 struct l2tp_stats stats; 125 struct hlist_node global_hlist; /* Global hash list node */ 126 127 int (*build_header)(struct l2tp_session *session, void *buf); 128 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 129 void (*session_close)(struct l2tp_session *session); 130 void (*ref)(struct l2tp_session *session); 131 void (*deref)(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 struct rcu_head rcu; 163 rwlock_t hlist_lock; /* protect session_hlist */ 164 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 165 /* hashed list of sessions, 166 * hashed by id */ 167 u32 tunnel_id; 168 u32 peer_tunnel_id; 169 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 170 171 char name[20]; /* for logging */ 172 int debug; /* bitmask of debug message 173 * categories */ 174 enum l2tp_encap_type encap; 175 struct l2tp_stats stats; 176 177 struct list_head list; /* Keep a list of all tunnels */ 178 struct net *l2tp_net; /* the net we belong to */ 179 180 atomic_t ref_count; 181 #ifdef CONFIG_DEBUG_FS 182 void (*show)(struct seq_file *m, void *arg); 183 #endif 184 int (*recv_payload_hook)(struct sk_buff *skb); 185 void (*old_sk_destruct)(struct sock *); 186 struct sock *sock; /* Parent socket */ 187 int fd; /* Parent fd, if tunnel socket 188 * was created by userspace */ 189 #if IS_ENABLED(CONFIG_IPV6) 190 bool v4mapped; 191 #endif 192 193 struct work_struct del_work; 194 195 uint8_t priv[0]; /* private data */ 196 }; 197 198 struct l2tp_nl_cmd_ops { 199 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg); 200 int (*session_delete)(struct l2tp_session *session); 201 }; 202 203 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel) 204 { 205 return &tunnel->priv[0]; 206 } 207 208 static inline void *l2tp_session_priv(struct l2tp_session *session) 209 { 210 return &session->priv[0]; 211 } 212 213 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk) 214 { 215 struct l2tp_tunnel *tunnel; 216 217 if (sk == NULL) 218 return NULL; 219 220 sock_hold(sk); 221 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data); 222 if (tunnel == NULL) { 223 sock_put(sk); 224 goto out; 225 } 226 227 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 228 229 out: 230 return tunnel; 231 } 232 233 struct l2tp_session *l2tp_session_find(struct net *net, 234 struct l2tp_tunnel *tunnel, 235 u32 session_id); 236 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth); 237 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname); 238 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id); 239 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth); 240 241 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, 242 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, 243 struct l2tp_tunnel **tunnelp); 244 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); 245 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 246 struct l2tp_session *l2tp_session_create(int priv_size, 247 struct l2tp_tunnel *tunnel, 248 u32 session_id, u32 peer_session_id, 249 struct l2tp_session_cfg *cfg); 250 void __l2tp_session_unhash(struct l2tp_session *session); 251 int l2tp_session_delete(struct l2tp_session *session); 252 void l2tp_session_free(struct l2tp_session *session); 253 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 254 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 255 int length, int (*payload_hook)(struct sk_buff *skb)); 256 int l2tp_session_queue_purge(struct l2tp_session *session); 257 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 258 void l2tp_session_set_header_len(struct l2tp_session *session, int version); 259 260 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, 261 int hdr_len); 262 263 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, 264 const struct l2tp_nl_cmd_ops *ops); 265 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 266 267 /* Session reference counts. Incremented when code obtains a reference 268 * to a session. 269 */ 270 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session) 271 { 272 atomic_inc(&session->ref_count); 273 } 274 275 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session) 276 { 277 if (atomic_dec_and_test(&session->ref_count)) 278 l2tp_session_free(session); 279 } 280 281 #ifdef L2TP_REFCNT_DEBUG 282 #define l2tp_session_inc_refcount(_s) \ 283 do { \ 284 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \ 285 __func__, __LINE__, (_s)->name, \ 286 atomic_read(&_s->ref_count)); \ 287 l2tp_session_inc_refcount_1(_s); \ 288 } while (0) 289 #define l2tp_session_dec_refcount(_s) \ 290 do { \ 291 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \ 292 __func__, __LINE__, (_s)->name, \ 293 atomic_read(&_s->ref_count)); \ 294 l2tp_session_dec_refcount_1(_s); \ 295 } while (0) 296 #else 297 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s) 298 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s) 299 #endif 300 301 #define l2tp_printk(ptr, type, func, fmt, ...) \ 302 do { \ 303 if (((ptr)->debug) & (type)) \ 304 func(fmt, ##__VA_ARGS__); \ 305 } while (0) 306 307 #define l2tp_warn(ptr, type, fmt, ...) \ 308 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 309 #define l2tp_info(ptr, type, fmt, ...) \ 310 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 311 #define l2tp_dbg(ptr, type, fmt, ...) \ 312 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 313 314 #define MODULE_ALIAS_L2TP_PWTYPE(type) \ 315 MODULE_ALIAS("net-l2tp-type-" __stringify(type)) 316 317 #endif /* _L2TP_CORE_H_ */ 318