net/l2tp/l2tp_core.h

   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                     l2specific_type; /* Layer 2 specific type */
  63         u8                      cookie[8];      /* optional cookie */
  64         int                     cookie_len;     /* 0, 4 or 8 bytes */
  65         u8                      peer_cookie[8]; /* peer's cookie */
  66         int                     peer_cookie_len; /* 0, 4 or 8 bytes */
  67         int                     reorder_timeout; /* configured reorder timeout
  68                                                   * (in jiffies) */
  69         int                     mtu;
  70         int                     mru;
  71         char                    *ifname;
  72 };
  73
  74 struct l2tp_session {
  75         int                     magic;          /* should be
  76                                                  * L2TP_SESSION_MAGIC */
  77         long                    dead;
  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                     l2specific_type;
  88         u16                     hdr_len;
  89         u32                     nr;             /* session NR state (receive) */
  90         u32                     ns;             /* session NR state (send) */
  91         struct sk_buff_head     reorder_q;      /* receive reorder queue */
  92         u32                     nr_max;         /* max NR. Depends on tunnel */
  93         u32                     nr_window_size; /* NR window size */
  94         u32                     nr_oos;         /* NR of last OOS packet */
  95         int                     nr_oos_count;   /* For OOS recovery */
  96         int                     nr_oos_count_max;
  97         struct hlist_node       hlist;          /* Hash list node */
  98         refcount_t              ref_count;
  99
 100         char                    name[32];       /* for logging */
 101         char                    ifname[IFNAMSIZ];
 102         unsigned int            data_seq:2;     /* data sequencing level
 103                                                  * 0 => none, 1 => IP only,
 104                                                  * 2 => all
 105                                                  */
 106         unsigned int            recv_seq:1;     /* expect receive packets with
 107                                                  * sequence numbers? */
 108         unsigned int            send_seq:1;     /* send packets with sequence
 109                                                  * numbers? */
 110         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
 111                                                  * sequence numbers under
 112                                                  * control of LNS. */
 113         int                     debug;          /* bitmask of debug message
 114                                                  * categories */
 115         int                     reorder_timeout; /* configured reorder timeout
 116                                                   * (in jiffies) */
 117         int                     reorder_skip;   /* set if skip to next nr */
 118         int                     mtu;
 119         int                     mru;
 120         enum l2tp_pwtype        pwtype;
 121         struct l2tp_stats       stats;
 122         struct hlist_node       global_hlist;   /* Global hash list node */
 123
 124         int (*build_header)(struct l2tp_session *session, void *buf);
 125         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 126         void (*session_close)(struct l2tp_session *session);
 127 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 128         void (*show)(struct seq_file *m, void *priv);
 129 #endif
 130         uint8_t                 priv[0];        /* private data */
 131 };
 132
 133 /* Describes the tunnel. It contains info to track all the associated
 134  * sessions so incoming packets can be sorted out
 135  */
 136 struct l2tp_tunnel_cfg {
 137         int                     debug;          /* bitmask of debug message
 138                                                  * categories */
 139         enum l2tp_encap_type    encap;
 140
 141         /* Used only for kernel-created sockets */
 142         struct in_addr          local_ip;
 143         struct in_addr          peer_ip;
 144 #if IS_ENABLED(CONFIG_IPV6)
 145         struct in6_addr         *local_ip6;
 146         struct in6_addr         *peer_ip6;
 147 #endif
 148         u16                     local_udp_port;
 149         u16                     peer_udp_port;
 150         unsigned int            use_udp_checksums:1,
 151                                 udp6_zero_tx_checksums:1,
 152                                 udp6_zero_rx_checksums:1;
 153 };
 154
 155 struct l2tp_tunnel {
 156         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 157
 158         unsigned long           dead;
 159
 160         struct rcu_head rcu;
 161         rwlock_t                hlist_lock;     /* protect session_hlist */
 162         bool                    acpt_newsess;   /* Indicates whether this
 163                                                  * tunnel accepts new sessions.
 164                                                  * Protected by hlist_lock.
 165                                                  */
 166         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 167                                                 /* hashed list of sessions,
 168                                                  * hashed by id */
 169         u32                     tunnel_id;
 170         u32                     peer_tunnel_id;
 171         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 172
 173         char                    name[20];       /* for logging */
 174         int                     debug;          /* bitmask of debug message
 175                                                  * categories */
 176         enum l2tp_encap_type    encap;
 177         struct l2tp_stats       stats;
 178
 179         struct list_head        list;           /* Keep a list of all tunnels */
 180         struct net              *l2tp_net;      /* the net we belong to */
 181
 182         refcount_t              ref_count;
 183 #ifdef CONFIG_DEBUG_FS
 184         void (*show)(struct seq_file *m, void *arg);
 185 #endif
 186         int (*recv_payload_hook)(struct sk_buff *skb);
 187         void (*old_sk_destruct)(struct sock *);
 188         struct sock             *sock;          /* Parent socket */
 189         int                     fd;             /* Parent fd, if tunnel socket
 190                                                  * was created by userspace */
 191 #if IS_ENABLED(CONFIG_IPV6)
 192         bool                    v4mapped;
 193 #endif
 194
 195         struct work_struct      del_work;
 196
 197         uint8_t                 priv[0];        /* private data */
 198 };
 199
 200 struct l2tp_nl_cmd_ops {
 201         int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
 202                               u32 session_id, u32 peer_session_id,
 203                               struct l2tp_session_cfg *cfg);
 204         int (*session_delete)(struct l2tp_session *session);
 205 };
 206
 207 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 208 {
 209         return &tunnel->priv[0];
 210 }
 211
 212 static inline void *l2tp_session_priv(struct l2tp_session *session)
 213 {
 214         return &session->priv[0];
 215 }
 216
 217 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
 218 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
 219
 220 struct l2tp_session *l2tp_session_get(const struct net *net,
 221                                       struct l2tp_tunnel *tunnel,
 222                                       u32 session_id);
 223 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
 224 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
 225                                                 const char *ifname);
 226 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id);
 227 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
 228
 229 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
 230                        u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
 231                        struct l2tp_tunnel **tunnelp);
 232 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 233 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 234 struct l2tp_session *l2tp_session_create(int priv_size,
 235                                          struct l2tp_tunnel *tunnel,
 236                                          u32 session_id, u32 peer_session_id,
 237                                          struct l2tp_session_cfg *cfg);
 238 int l2tp_session_register(struct l2tp_session *session,
 239                           struct l2tp_tunnel *tunnel);
 240
 241 void __l2tp_session_unhash(struct l2tp_session *session);
 242 int l2tp_session_delete(struct l2tp_session *session);
 243 void l2tp_session_free(struct l2tp_session *session);
 244 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 245                       unsigned char *ptr, unsigned char *optr, u16 hdrflags,
 246                       int length, int (*payload_hook)(struct sk_buff *skb));
 247 int l2tp_session_queue_purge(struct l2tp_session *session);
 248 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 249 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 250
 251 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
 252                   int hdr_len);
 253
 254 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
 255                          const struct l2tp_nl_cmd_ops *ops);
 256 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 257 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 258
 259 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
 260 {
 261         refcount_inc(&tunnel->ref_count);
 262 }
 263
 264 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
 265 {
 266         if (refcount_dec_and_test(&tunnel->ref_count))
 267                 l2tp_tunnel_free(tunnel);
 268 }
 269
 270 /* Session reference counts. Incremented when code obtains a reference
 271  * to a session.
 272  */
 273 static inline void l2tp_session_inc_refcount(struct l2tp_session *session)
 274 {
 275         refcount_inc(&session->ref_count);
 276 }
 277
 278 static inline void l2tp_session_dec_refcount(struct l2tp_session *session)
 279 {
 280         if (refcount_dec_and_test(&session->ref_count))
 281                 l2tp_session_free(session);
 282 }
 283
 284 static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
 285 {
 286         switch (session->l2specific_type) {
 287         case L2TP_L2SPECTYPE_DEFAULT:
 288                 return 4;
 289         case L2TP_L2SPECTYPE_NONE:
 290         default:
 291                 return 0;
 292         }
 293 }
 294
 295 #define l2tp_printk(ptr, type, func, fmt, ...)                          \
 296 do {                                                                    \
 297         if (((ptr)->debug) & (type))                                    \
 298                 func(fmt, ##__VA_ARGS__);                               \
 299 } while (0)
 300
 301 #define l2tp_warn(ptr, type, fmt, ...)                                  \
 302         l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
 303 #define l2tp_info(ptr, type, fmt, ...)                                  \
 304         l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
 305 #define l2tp_dbg(ptr, type, fmt, ...)                                   \
 306         l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
 307
 308 #define MODULE_ALIAS_L2TP_PWTYPE(type) \
 309         MODULE_ALIAS("net-l2tp-type-" __stringify(type))
 310
 311 #endif /* _L2TP_CORE_H_ */