1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* L2TP internal definitions. 3 * 4 * Copyright (c) 2008,2009 Katalix Systems Ltd 5 */ 6 #include <linux/refcount.h> 7 8 #ifndef _L2TP_CORE_H_ 9 #define _L2TP_CORE_H_ 10 11 #include <net/dst.h> 12 #include <net/sock.h> 13 14 #ifdef CONFIG_XFRM 15 #include <net/xfrm.h> 16 #endif 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 BIT(L2TP_HASH_BITS) 25 26 /* System-wide, session hash table size */ 27 #define L2TP_HASH_BITS_2 8 28 #define L2TP_HASH_SIZE_2 BIT(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 sequence numbers? */ 52 unsigned int send_seq:1; /* send packets with sequence numbers? */ 53 unsigned int lns_mode:1; /* behave as LNS? 54 * LAC enables sequence numbers under LNS control. 55 */ 56 int debug; /* bitmask of debug message categories */ 57 u16 l2specific_type; /* Layer 2 specific type */ 58 u8 cookie[8]; /* optional cookie */ 59 int cookie_len; /* 0, 4 or 8 bytes */ 60 u8 peer_cookie[8]; /* peer's cookie */ 61 int peer_cookie_len; /* 0, 4 or 8 bytes */ 62 int reorder_timeout; /* configured reorder timeout (in jiffies) */ 63 char *ifname; 64 }; 65 66 struct l2tp_session { 67 int magic; /* should be L2TP_SESSION_MAGIC */ 68 long dead; 69 70 struct l2tp_tunnel *tunnel; /* back pointer to tunnel context */ 71 u32 session_id; 72 u32 peer_session_id; 73 u8 cookie[8]; 74 int cookie_len; 75 u8 peer_cookie[8]; 76 int peer_cookie_len; 77 u16 l2specific_type; 78 u16 hdr_len; 79 u32 nr; /* session NR state (receive) */ 80 u32 ns; /* session NR state (send) */ 81 struct sk_buff_head reorder_q; /* receive reorder queue */ 82 u32 nr_max; /* max NR. Depends on tunnel */ 83 u32 nr_window_size; /* NR window size */ 84 u32 nr_oos; /* NR of last OOS packet */ 85 int nr_oos_count; /* for OOS recovery */ 86 int nr_oos_count_max; 87 struct hlist_node hlist; /* hash list node */ 88 refcount_t ref_count; 89 90 char name[32]; /* for logging */ 91 char ifname[IFNAMSIZ]; 92 unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */ 93 unsigned int send_seq:1; /* send packets with sequence numbers? */ 94 unsigned int lns_mode:1; /* behave as LNS? 95 * LAC enables sequence numbers under LNS control. 96 */ 97 int debug; /* bitmask of debug message categories */ 98 int reorder_timeout; /* configured reorder timeout (in jiffies) */ 99 int reorder_skip; /* set if skip to next nr */ 100 enum l2tp_pwtype pwtype; 101 struct l2tp_stats stats; 102 struct hlist_node global_hlist; /* global hash list node */ 103 104 int (*build_header)(struct l2tp_session *session, void *buf); 105 void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); 106 void (*session_close)(struct l2tp_session *session); 107 void (*show)(struct seq_file *m, void *priv); 108 u8 priv[]; /* private data */ 109 }; 110 111 /* Describes the tunnel. It contains info to track all the associated 112 * sessions so incoming packets can be sorted out 113 */ 114 struct l2tp_tunnel_cfg { 115 int debug; /* bitmask of debug message categories */ 116 enum l2tp_encap_type encap; 117 118 /* Used only for kernel-created sockets */ 119 struct in_addr local_ip; 120 struct in_addr peer_ip; 121 #if IS_ENABLED(CONFIG_IPV6) 122 struct in6_addr *local_ip6; 123 struct in6_addr *peer_ip6; 124 #endif 125 u16 local_udp_port; 126 u16 peer_udp_port; 127 unsigned int use_udp_checksums:1, 128 udp6_zero_tx_checksums:1, 129 udp6_zero_rx_checksums:1; 130 }; 131 132 struct l2tp_tunnel { 133 int magic; /* Should be L2TP_TUNNEL_MAGIC */ 134 135 unsigned long dead; 136 137 struct rcu_head rcu; 138 rwlock_t hlist_lock; /* protect session_hlist */ 139 bool acpt_newsess; /* indicates whether this tunnel accepts 140 * new sessions. Protected by hlist_lock. 141 */ 142 struct hlist_head session_hlist[L2TP_HASH_SIZE]; 143 /* hashed list of sessions, hashed by id */ 144 u32 tunnel_id; 145 u32 peer_tunnel_id; 146 int version; /* 2=>L2TPv2, 3=>L2TPv3 */ 147 148 char name[20]; /* for logging */ 149 int debug; /* bitmask of debug message categories */ 150 enum l2tp_encap_type encap; 151 struct l2tp_stats stats; 152 153 struct list_head list; /* list node on per-namespace list of tunnels */ 154 struct net *l2tp_net; /* the net we belong to */ 155 156 refcount_t ref_count; 157 void (*old_sk_destruct)(struct sock *sk); 158 struct sock *sock; /* parent socket */ 159 int fd; /* parent fd, if tunnel socket was created 160 * by userspace 161 */ 162 163 struct work_struct del_work; 164 }; 165 166 struct l2tp_nl_cmd_ops { 167 int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel, 168 u32 session_id, u32 peer_session_id, 169 struct l2tp_session_cfg *cfg); 170 int (*session_delete)(struct l2tp_session *session); 171 }; 172 173 static inline void *l2tp_session_priv(struct l2tp_session *session) 174 { 175 return &session->priv[0]; 176 } 177 178 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id); 179 struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth); 180 struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel, 181 u32 session_id); 182 183 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); 184 185 struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id); 186 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth); 187 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, 188 const char *ifname); 189 190 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, 191 u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, 192 struct l2tp_tunnel **tunnelp); 193 int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, 194 struct l2tp_tunnel_cfg *cfg); 195 196 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 197 struct l2tp_session *l2tp_session_create(int priv_size, 198 struct l2tp_tunnel *tunnel, 199 u32 session_id, u32 peer_session_id, 200 struct l2tp_session_cfg *cfg); 201 int l2tp_session_register(struct l2tp_session *session, 202 struct l2tp_tunnel *tunnel); 203 204 void __l2tp_session_unhash(struct l2tp_session *session); 205 int l2tp_session_delete(struct l2tp_session *session); 206 void l2tp_session_free(struct l2tp_session *session); 207 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 208 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 209 int length); 210 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); 211 void l2tp_session_set_header_len(struct l2tp_session *session, int version); 212 213 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, 214 int hdr_len); 215 216 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, 217 const struct l2tp_nl_cmd_ops *ops); 218 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 219 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); 220 221 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel) 222 { 223 refcount_inc(&tunnel->ref_count); 224 } 225 226 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) 227 { 228 if (refcount_dec_and_test(&tunnel->ref_count)) 229 l2tp_tunnel_free(tunnel); 230 } 231 232 /* Session reference counts. Incremented when code obtains a reference 233 * to a session. 234 */ 235 static inline void l2tp_session_inc_refcount(struct l2tp_session *session) 236 { 237 refcount_inc(&session->ref_count); 238 } 239 240 static inline void l2tp_session_dec_refcount(struct l2tp_session *session) 241 { 242 if (refcount_dec_and_test(&session->ref_count)) 243 l2tp_session_free(session); 244 } 245 246 static inline int l2tp_get_l2specific_len(struct l2tp_session *session) 247 { 248 switch (session->l2specific_type) { 249 case L2TP_L2SPECTYPE_DEFAULT: 250 return 4; 251 case L2TP_L2SPECTYPE_NONE: 252 default: 253 return 0; 254 } 255 } 256 257 static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel) 258 { 259 struct dst_entry *dst; 260 u32 mtu; 261 262 dst = sk_dst_get(tunnel->sock); 263 if (!dst) 264 return 0; 265 266 mtu = dst_mtu(dst); 267 dst_release(dst); 268 269 return mtu; 270 } 271 272 #ifdef CONFIG_XFRM 273 static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel) 274 { 275 struct sock *sk = tunnel->sock; 276 277 return sk && (rcu_access_pointer(sk->sk_policy[0]) || 278 rcu_access_pointer(sk->sk_policy[1])); 279 } 280 #else 281 static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel) 282 { 283 return false; 284 } 285 #endif 286 287 static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb, 288 unsigned char **ptr, unsigned char **optr) 289 { 290 int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session); 291 292 if (opt_len > 0) { 293 int off = *ptr - *optr; 294 295 if (!pskb_may_pull(skb, off + opt_len)) 296 return -1; 297 298 if (skb->data != *optr) { 299 *optr = skb->data; 300 *ptr = skb->data + off; 301 } 302 } 303 304 return 0; 305 } 306 307 #define l2tp_printk(ptr, type, func, fmt, ...) \ 308 do { \ 309 if (((ptr)->debug) & (type)) \ 310 func(fmt, ##__VA_ARGS__); \ 311 } while (0) 312 313 #define l2tp_warn(ptr, type, fmt, ...) \ 314 l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) 315 #define l2tp_info(ptr, type, fmt, ...) \ 316 l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) 317 #define l2tp_dbg(ptr, type, fmt, ...) \ 318 l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) 319 320 #define MODULE_ALIAS_L2TP_PWTYPE(type) \ 321 MODULE_ALIAS("net-l2tp-type-" __stringify(type)) 322 323 #endif /* _L2TP_CORE_H_ */ 324