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 u64 tx_packets; 40 u64 tx_bytes; 41 u64 tx_errors; 42 u64 rx_packets; 43 u64 rx_bytes; 44 u64 rx_seq_discards; 45 u64 rx_oos_packets; 46 u64 rx_errors; 47 u64 rx_cookie_discards; 48 struct u64_stats_sync syncp; 49 }; 50 51 struct l2tp_tunnel; 52 53 /* Describes a session. Contains information to determine incoming 54 * packets and transmit outgoing ones. 55 */ 56 struct l2tp_session_cfg { 57 enum l2tp_pwtype pw_type; 58 unsigned int data_seq:2; /* data sequencing level 59 * 0 => none, 1 => IP only, 60 * 2 => all 61 */ 62 unsigned int recv_seq:1; /* expect receive packets with 63 * sequence numbers? */ 64 unsigned int send_seq:1; /* send packets with sequence 65 * numbers? */ 66 unsigned int lns_mode:1; /* behave as LNS? LAC enables 67 * sequence numbers under 68 * control of LNS. */ 69 int debug; /* bitmask of debug message 70 * categories */ 71 u16 vlan_id; /* VLAN pseudowire only */ 72 u16 offset; /* offset to payload */ 73 u16 l2specific_len; /* Layer 2 specific length */ 74 u16 l2specific_type; /* Layer 2 specific type */ 75 u8 cookie[8]; /* optional cookie */ 76 int cookie_len; /* 0, 4 or 8 bytes */ 77 u8 peer_cookie[8]; /* peer's cookie */ 78 int peer_cookie_len; /* 0, 4 or 8 bytes */ 79 int reorder_timeout; /* configured reorder timeout 80 * (in jiffies) */ 81 int mtu; 82 int mru; 83 char *ifname; 84 }; 85 86 struct l2tp_session { 87 int magic; /* should be 88 * L2TP_SESSION_MAGIC */ 89 90 struct l2tp_tunnel *tunnel; /* back pointer to tunnel 91 * context */ 92 u32 session_id; 93 u32 peer_session_id; 94 u8 cookie[8]; 95 int cookie_len; 96 u8 peer_cookie[8]; 97 int peer_cookie_len; 98 u16 offset; /* offset from end of L2TP header 99 to beginning of data */ 100 u16 l2specific_len; 101 u16 l2specific_type; 102 u16 hdr_len; 103 u32 nr; /* session NR state (receive) */ 104 u32 ns; /* session NR state (send) */ 105 struct sk_buff_head reorder_q; /* receive reorder queue */ 106 struct hlist_node hlist; /* Hash list node */ 107 atomic_t ref_count; 108 109 char name[32]; /* for logging */ 110 char ifname[IFNAMSIZ]; 111 unsigned int data_seq:2; /* data sequencing level 112 * 0 => none, 1 => IP only, 113 * 2 => all 114 */ 115 unsigned int recv_seq:1; /* expect receive packets with 116 * sequence numbers? */ 117 unsigned int send_seq:1; /* send packets with sequence 118 * numbers? */ 119 unsigned int lns_mode:1; /* behave as LNS? LAC enables 120 * sequence numbers under 121 * control of LNS. */ 122 int debug; /* bitmask of debug message 123 * categories */ 124 int reorder_timeout; /* configured reorder timeout 125 * (in jiffies) */ 126 int reorder_skip; /* set if skip to next nr */ 127 int mtu; 128 int mru; 129 enum l2tp_pwtype pwtype; 130 struct l2tp_stats stats; 131 struct hlist_node global_hlist; /* Global hash list node */ 132 133 int (*build_header)(struct l2tp_session *session, void *buf); 134 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 135 void (*session_close)(struct l2tp_session *session); 136 void (*ref)(struct l2tp_session *session); 137 void (*deref)(struct l2tp_session *session); 138 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE) 139 void (*show)(struct seq_file *m, void *priv); 140 #endif 141 uint8_t priv[0]; /* private data */ 142 }; 143 144 /* Describes the tunnel. It contains info to track all the associated 145 * sessions so incoming packets can be sorted out 146 */ 147 struct l2tp_tunnel_cfg { 148 int debug; /* bitmask of debug message 149 * categories */ 150 enum l2tp_encap_type encap; 151 152 /* Used only for kernel-created sockets */ 153 struct in_addr local_ip; 154 struct in_addr peer_ip; 155 #if IS_ENABLED(CONFIG_IPV6) 156 struct in6_addr *local_ip6; 157 struct in6_addr *peer_ip6; 158 #endif 159 u16 local_udp_port; 160 u16 peer_udp_port; 161 unsigned int use_udp_checksums:1; 162 }; 163 164 struct l2tp_tunnel { 165 int magic; /* Should be L2TP_TUNNEL_MAGIC */ 166 struct rcu_head rcu; 167 rwlock_t hlist_lock; /* protect session_hlist */ 168 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 169 /* hashed list of sessions, 170 * hashed by id */ 171 u32 tunnel_id; 172 u32 peer_tunnel_id; 173 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 174 175 char name[20]; /* for logging */ 176 int debug; /* bitmask of debug message 177 * categories */ 178 enum l2tp_encap_type encap; 179 struct l2tp_stats stats; 180 181 struct list_head list; /* Keep a list of all tunnels */ 182 struct net *l2tp_net; /* the net we belong to */ 183 184 atomic_t ref_count; 185 #ifdef CONFIG_DEBUG_FS 186 void (*show)(struct seq_file *m, void *arg); 187 #endif 188 int (*recv_payload_hook)(struct sk_buff *skb); 189 void (*old_sk_destruct)(struct sock *); 190 struct sock *sock; /* Parent socket */ 191 int fd; 192 193 uint8_t priv[0]; /* private data */ 194 }; 195 196 struct l2tp_nl_cmd_ops { 197 int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg); 198 int (*session_delete)(struct l2tp_session *session); 199 }; 200 201 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel) 202 { 203 return &tunnel->priv[0]; 204 } 205 206 static inline void *l2tp_session_priv(struct l2tp_session *session) 207 { 208 return &session->priv[0]; 209 } 210 211 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk) 212 { 213 struct l2tp_tunnel *tunnel; 214 215 if (sk == NULL) 216 return NULL; 217 218 sock_hold(sk); 219 tunnel = (struct l2tp_tunnel *)(sk->sk_user_data); 220 if (tunnel == NULL) { 221 sock_put(sk); 222 goto out; 223 } 224 225 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 226 227 out: 228 return tunnel; 229 } 230 231 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id); 232 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth); 233 extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname); 234 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id); 235 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth); 236 237 extern int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp); 238 extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 239 extern struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg); 240 extern int l2tp_session_delete(struct l2tp_session *session); 241 extern void l2tp_session_free(struct l2tp_session *session); 242 extern void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, unsigned char *ptr, unsigned char *optr, u16 hdrflags, int length, int (*payload_hook)(struct sk_buff *skb)); 243 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 244 245 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len); 246 247 extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops); 248 extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 249 250 /* Session reference counts. Incremented when code obtains a reference 251 * to a session. 252 */ 253 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session) 254 { 255 atomic_inc(&session->ref_count); 256 } 257 258 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session) 259 { 260 if (atomic_dec_and_test(&session->ref_count)) 261 l2tp_session_free(session); 262 } 263 264 #ifdef L2TP_REFCNT_DEBUG 265 #define l2tp_session_inc_refcount(_s) \ 266 do { \ 267 pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \ 268 __func__, __LINE__, (_s)->name, \ 269 atomic_read(&_s->ref_count)); \ 270 l2tp_session_inc_refcount_1(_s); \ 271 } while (0) 272 #define l2tp_session_dec_refcount(_s) \ 273 do { \ 274 pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \ 275 __func__, __LINE__, (_s)->name, \ 276 atomic_read(&_s->ref_count)); \ 277 l2tp_session_dec_refcount_1(_s); \ 278 } while (0) 279 #else 280 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s) 281 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s) 282 #endif 283 284 #define l2tp_printk(ptr, type, func, fmt, ...) \ 285 do { \ 286 if (((ptr)->debug) & (type)) \ 287 func(fmt, ##__VA_ARGS__); \ 288 } while (0) 289 290 #define l2tp_warn(ptr, type, fmt, ...) \ 291 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 292 #define l2tp_info(ptr, type, fmt, ...) \ 293 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 294 #define l2tp_dbg(ptr, type, fmt, ...) \ 295 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 296 297 #endif /* _L2TP_CORE_H_ */ 298