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                     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         long                    dead;
  80
  81         struct l2tp_tunnel      *tunnel;        /* back pointer to tunnel
  82                                                  * context */
  83         u32                     session_id;
  84         u32                     peer_session_id;
  85         u8                      cookie[8];
  86         int                     cookie_len;
  87         u8                      peer_cookie[8];
  88         int                     peer_cookie_len;
  89         u16                     offset;         /* offset from end of L2TP header
  90                                                    to beginning of data */
  91         u16                     l2specific_len;
  92         u16                     l2specific_type;
  93         u16                     hdr_len;
  94         u32                     nr;             /* session NR state (receive) */
  95         u32                     ns;             /* session NR state (send) */
  96         struct sk_buff_head     reorder_q;      /* receive reorder queue */
  97         u32                     nr_max;         /* max NR. Depends on tunnel */
  98         u32                     nr_window_size; /* NR window size */
  99         u32                     nr_oos;         /* NR of last OOS packet */
 100         int                     nr_oos_count;   /* For OOS recovery */
 101         int                     nr_oos_count_max;
 102         struct hlist_node       hlist;          /* Hash list node */
 103         refcount_t              ref_count;
 104
 105         char                    name[32];       /* for logging */
 106         char                    ifname[IFNAMSIZ];
 107         unsigned int            data_seq:2;     /* data sequencing level
 108                                                  * 0 => none, 1 => IP only,
 109                                                  * 2 => all
 110                                                  */
 111         unsigned int            recv_seq:1;     /* expect receive packets with
 112                                                  * sequence numbers? */
 113         unsigned int            send_seq:1;     /* send packets with sequence
 114                                                  * numbers? */
 115         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
 116                                                  * sequence numbers under
 117                                                  * control of LNS. */
 118         int                     debug;          /* bitmask of debug message
 119                                                  * categories */
 120         int                     reorder_timeout; /* configured reorder timeout
 121                                                   * (in jiffies) */
 122         int                     reorder_skip;   /* set if skip to next nr */
 123         int                     mtu;
 124         int                     mru;
 125         enum l2tp_pwtype        pwtype;
 126         struct l2tp_stats       stats;
 127         struct hlist_node       global_hlist;   /* Global hash list node */
 128
 129         int (*build_header)(struct l2tp_session *session, void *buf);
 130         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 131         void (*session_close)(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
 163         unsigned long           dead;
 164
 165         struct rcu_head rcu;
 166         rwlock_t                hlist_lock;     /* protect session_hlist */
 167         bool                    acpt_newsess;   /* Indicates whether this
 168                                                  * tunnel accepts new sessions.
 169                                                  * Protected by hlist_lock.
 170                                                  */
 171         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 172                                                 /* hashed list of sessions,
 173                                                  * hashed by id */
 174         u32                     tunnel_id;
 175         u32                     peer_tunnel_id;
 176         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 177
 178         char                    name[20];       /* for logging */
 179         int                     debug;          /* bitmask of debug message
 180                                                  * categories */
 181         enum l2tp_encap_type    encap;
 182         struct l2tp_stats       stats;
 183
 184         struct list_head        list;           /* Keep a list of all tunnels */
 185         struct net              *l2tp_net;      /* the net we belong to */
 186
 187         refcount_t              ref_count;
 188 #ifdef CONFIG_DEBUG_FS
 189         void (*show)(struct seq_file *m, void *arg);
 190 #endif
 191         int (*recv_payload_hook)(struct sk_buff *skb);
 192         void (*old_sk_destruct)(struct sock *);
 193         struct sock             *sock;          /* Parent socket */
 194         int                     fd;             /* Parent fd, if tunnel socket
 195                                                  * was created by userspace */
 196 #if IS_ENABLED(CONFIG_IPV6)
 197         bool                    v4mapped;
 198 #endif
 199
 200         struct work_struct      del_work;
 201
 202         uint8_t                 priv[0];        /* private data */
 203 };
 204
 205 struct l2tp_nl_cmd_ops {
 206         int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
 207                               u32 session_id, u32 peer_session_id,
 208                               struct l2tp_session_cfg *cfg);
 209         int (*session_delete)(struct l2tp_session *session);
 210 };
 211
 212 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 213 {
 214         return &tunnel->priv[0];
 215 }
 216
 217 static inline void *l2tp_session_priv(struct l2tp_session *session)
 218 {
 219         return &session->priv[0];
 220 }
 221
 222 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 223 {
 224         struct l2tp_tunnel *tunnel;
 225
 226         if (sk == NULL)
 227                 return NULL;
 228
 229         sock_hold(sk);
 230         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 231         if (tunnel == NULL) {
 232                 sock_put(sk);
 233                 goto out;
 234         }
 235
 236         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 237
 238 out:
 239         return tunnel;
 240 }
 241
 242 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
 243
 244 struct l2tp_session *l2tp_session_get(const struct net *net,
 245                                       struct l2tp_tunnel *tunnel,
 246                                       u32 session_id);
 247 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
 248 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
 249                                                 const char *ifname);
 250 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id);
 251 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
 252
 253 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
 254                        u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
 255                        struct l2tp_tunnel **tunnelp);
 256 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 257 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 258 struct l2tp_session *l2tp_session_create(int priv_size,
 259                                          struct l2tp_tunnel *tunnel,
 260                                          u32 session_id, u32 peer_session_id,
 261                                          struct l2tp_session_cfg *cfg);
 262 int l2tp_session_register(struct l2tp_session *session,
 263                           struct l2tp_tunnel *tunnel);
 264
 265 void __l2tp_session_unhash(struct l2tp_session *session);
 266 int l2tp_session_delete(struct l2tp_session *session);
 267 void l2tp_session_free(struct l2tp_session *session);
 268 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 269                       unsigned char *ptr, unsigned char *optr, u16 hdrflags,
 270                       int length, int (*payload_hook)(struct sk_buff *skb));
 271 int l2tp_session_queue_purge(struct l2tp_session *session);
 272 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 273 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 274
 275 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
 276                   int hdr_len);
 277
 278 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
 279                          const struct l2tp_nl_cmd_ops *ops);
 280 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 281 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 282
 283 static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
 284 {
 285         refcount_inc(&tunnel->ref_count);
 286 }
 287
 288 static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
 289 {
 290         if (refcount_dec_and_test(&tunnel->ref_count))
 291                 kfree_rcu(tunnel, rcu);
 292 }
 293
 294 /* Session reference counts. Incremented when code obtains a reference
 295  * to a session.
 296  */
 297 static inline void l2tp_session_inc_refcount(struct l2tp_session *session)
 298 {
 299         refcount_inc(&session->ref_count);
 300 }
 301
 302 static inline void l2tp_session_dec_refcount(struct l2tp_session *session)
 303 {
 304         if (refcount_dec_and_test(&session->ref_count))
 305                 l2tp_session_free(session);
 306 }
 307
 308 #define l2tp_printk(ptr, type, func, fmt, ...)                          \
 309 do {                                                                    \
 310         if (((ptr)->debug) & (type))                                    \
 311                 func(fmt, ##__VA_ARGS__);                               \
 312 } while (0)
 313
 314 #define l2tp_warn(ptr, type, fmt, ...)                                  \
 315         l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
 316 #define l2tp_info(ptr, type, fmt, ...)                                  \
 317         l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
 318 #define l2tp_dbg(ptr, type, fmt, ...)                                   \
 319         l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
 320
 321 #define MODULE_ALIAS_L2TP_PWTYPE(type) \
 322         MODULE_ALIAS("net-l2tp-type-" __stringify(type))
 323
 324 #endif /* _L2TP_CORE_H_ */