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 offset; /* offset to payload */ 63 u16 l2specific_len; /* Layer 2 specific length */ 64 u16 l2specific_type; /* Layer 2 specific type */ 65 u8 cookie[8]; /* optional cookie */ 66 int cookie_len; /* 0, 4 or 8 bytes */ 67 u8 peer_cookie[8]; /* peer's cookie */ 68 int peer_cookie_len; /* 0, 4 or 8 bytes */ 69 int reorder_timeout; /* configured reorder timeout 70 * (in jiffies) */ 71 int mtu; 72 int mru; 73 char *ifname; 74 }; 75 76 struct l2tp_session { 77 int magic; /* should be 78 * L2TP_SESSION_MAGIC */ 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 offset; /* offset from end of L2TP header 89 to beginning of data */ 90 u16 l2specific_len; 91 u16 l2specific_type; 92 u16 hdr_len; 93 u32 nr; /* session NR state (receive) */ 94 u32 ns; /* session NR state (send) */ 95 struct sk_buff_head reorder_q; /* receive reorder queue */ 96 u32 nr_max; /* max NR. Depends on tunnel */ 97 u32 nr_window_size; /* NR window size */ 98 u32 nr_oos; /* NR of last OOS packet */ 99 int nr_oos_count; /* For OOS recovery */ 100 int nr_oos_count_max; 101 struct hlist_node hlist; /* Hash list node */ 102 refcount_t ref_count; 103 104 char name[32]; /* for logging */ 105 char ifname[IFNAMSIZ]; 106 unsigned int data_seq:2; /* data sequencing level 107 * 0 => none, 1 => IP only, 108 * 2 => all 109 */ 110 unsigned int recv_seq:1; /* expect receive packets with 111 * sequence numbers? */ 112 unsigned int send_seq:1; /* send packets with sequence 113 * numbers? */ 114 unsigned int lns_mode:1; /* behave as LNS? LAC enables 115 * sequence numbers under 116 * control of LNS. */ 117 int debug; /* bitmask of debug message 118 * categories */ 119 int reorder_timeout; /* configured reorder timeout 120 * (in jiffies) */ 121 int reorder_skip; /* set if skip to next nr */ 122 int mtu; 123 int mru; 124 enum l2tp_pwtype pwtype; 125 struct l2tp_stats stats; 126 struct hlist_node global_hlist; /* Global hash list node */ 127 128 int (*build_header)(struct l2tp_session *session, void *buf); 129 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 130 void (*session_close)(struct l2tp_session *session); 131 void (*ref)(struct l2tp_session *session); 132 void (*deref)(struct l2tp_session *session); 133 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) 134 void (*show)(struct seq_file *m, void *priv); 135 #endif 136 uint8_t priv[0]; /* private data */ 137 }; 138 139 /* Describes the tunnel. It contains info to track all the associated 140 * sessions so incoming packets can be sorted out 141 */ 142 struct l2tp_tunnel_cfg { 143 int debug; /* bitmask of debug message 144 * categories */ 145 enum l2tp_encap_type encap; 146 147 /* Used only for kernel-created sockets */ 148 struct in_addr local_ip; 149 struct in_addr peer_ip; 150 #if IS_ENABLED(CONFIG_IPV6) 151 struct in6_addr *local_ip6; 152 struct in6_addr *peer_ip6; 153 #endif 154 u16 local_udp_port; 155 u16 peer_udp_port; 156 unsigned int use_udp_checksums:1, 157 udp6_zero_tx_checksums:1, 158 udp6_zero_rx_checksums:1; 159 }; 160 161 struct l2tp_tunnel { 162 int magic; /* Should be L2TP_TUNNEL_MAGIC */ 163 struct rcu_head rcu; 164 rwlock_t hlist_lock; /* protect session_hlist */ 165 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 166 /* hashed list of sessions, 167 * hashed by id */ 168 u32 tunnel_id; 169 u32 peer_tunnel_id; 170 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 171 172 char name[20]; /* for logging */ 173 int debug; /* bitmask of debug message 174 * categories */ 175 enum l2tp_encap_type encap; 176 struct l2tp_stats stats; 177 178 struct list_head list; /* Keep a list of all tunnels */ 179 struct net *l2tp_net; /* the net we belong to */ 180 181 refcount_t ref_count; 182 #ifdef CONFIG_DEBUG_FS 183 void (*show)(struct seq_file *m, void *arg); 184 #endif 185 int (*recv_payload_hook)(struct sk_buff *skb); 186 void (*old_sk_destruct)(struct sock *); 187 struct sock *sock; /* Parent socket */ 188 int fd; /* Parent fd, if tunnel socket 189 * was created by userspace */ 190 #if IS_ENABLED(CONFIG_IPV6) 191 bool v4mapped; 192 #endif 193 194 struct work_struct del_work; 195 196 uint8_t priv[0]; /* private data */ 197 }; 198 199 struct l2tp_nl_cmd_ops { 200 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, 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 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk) 215 { 216 struct l2tp_tunnel *tunnel; 217 218 if (sk == NULL) 219 return NULL; 220 221 sock_hold(sk); 222 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data); 223 if (tunnel == NULL) { 224 sock_put(sk); 225 goto out; 226 } 227 228 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 229 230 out: 231 return tunnel; 232 } 233 234 struct l2tp_session *l2tp_session_get(const struct net *net, 235 struct l2tp_tunnel *tunnel, 236 u32 session_id, bool do_ref); 237 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth, 238 bool do_ref); 239 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, 240 const char *ifname, 241 bool do_ref); 242 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id); 243 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth); 244 245 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, 246 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, 247 struct l2tp_tunnel **tunnelp); 248 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); 249 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 250 struct l2tp_session *l2tp_session_create(int priv_size, 251 struct l2tp_tunnel *tunnel, 252 u32 session_id, u32 peer_session_id, 253 struct l2tp_session_cfg *cfg); 254 void __l2tp_session_unhash(struct l2tp_session *session); 255 int l2tp_session_delete(struct l2tp_session *session); 256 void l2tp_session_free(struct l2tp_session *session); 257 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 258 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 259 int length, int (*payload_hook)(struct sk_buff *skb)); 260 int l2tp_session_queue_purge(struct l2tp_session *session); 261 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 262 void l2tp_session_set_header_len(struct l2tp_session *session, int version); 263 264 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, 265 int hdr_len); 266 267 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, 268 const struct l2tp_nl_cmd_ops *ops); 269 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 270 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); 271 272 /* Session reference counts. Incremented when code obtains a reference 273 * to a session. 274 */ 275 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session) 276 { 277 refcount_inc(&session->ref_count); 278 } 279 280 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session) 281 { 282 if (refcount_dec_and_test(&session->ref_count)) 283 l2tp_session_free(session); 284 } 285 286 #ifdef L2TP_REFCNT_DEBUG 287 #define l2tp_session_inc_refcount(_s) \ 288 do { \ 289 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \ 290 __func__, __LINE__, (_s)->name, \ 291 refcount_read(&_s->ref_count)); \ 292 l2tp_session_inc_refcount_1(_s); \ 293 } while (0) 294 #define l2tp_session_dec_refcount(_s) \ 295 do { \ 296 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \ 297 __func__, __LINE__, (_s)->name, \ 298 refcount_read(&_s->ref_count)); \ 299 l2tp_session_dec_refcount_1(_s); \ 300 } while (0) 301 #else 302 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s) 303 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s) 304 #endif 305 306 #define l2tp_printk(ptr, type, func, fmt, ...) \ 307 do { \ 308 if (((ptr)->debug) & (type)) \ 309 func(fmt, ##__VA_ARGS__); \ 310 } while (0) 311 312 #define l2tp_warn(ptr, type, fmt, ...) \ 313 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 314 #define l2tp_info(ptr, type, fmt, ...) \ 315 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 316 #define l2tp_dbg(ptr, type, fmt, ...) \ 317 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 318 319 #define MODULE_ALIAS_L2TP_PWTYPE(type) \ 320 MODULE_ALIAS("net-l2tp-type-" __stringify(type)) 321 322 #endif /* _L2TP_CORE_H_ */ 323