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
  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         atomic_long_t           tx_packets;
  40         atomic_long_t           tx_bytes;
  41         atomic_long_t           tx_errors;
  42         atomic_long_t           rx_packets;
  43         atomic_long_t           rx_bytes;
  44         atomic_long_t           rx_seq_discards;
  45         atomic_long_t           rx_oos_packets;
  46         atomic_long_t           rx_errors;
  47         atomic_long_t           rx_cookie_discards;
  48 };
  49
  50 struct l2tp_tunnel;
  51
  52 /* Describes a session. Contains information to determine incoming
  53  * packets and transmit outgoing ones.
  54  */
  55 struct l2tp_session_cfg {
  56         enum l2tp_pwtype        pw_type;
  57         unsigned int            data_seq:2;     /* data sequencing level
  58                                                  * 0 => none, 1 => IP only,
  59                                                  * 2 => all
  60                                                  */
  61         unsigned int            recv_seq:1;     /* expect receive packets with
  62                                                  * sequence numbers? */
  63         unsigned int            send_seq:1;     /* send packets with sequence
  64                                                  * numbers? */
  65         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
  66                                                  * sequence numbers under
  67                                                  * control of LNS. */
  68         int                     debug;          /* bitmask of debug message
  69                                                  * categories */
  70         u16                     vlan_id;        /* VLAN pseudowire only */
  71         u16                     offset;         /* offset to payload */
  72         u16                     l2specific_len; /* Layer 2 specific length */
  73         u16                     l2specific_type; /* Layer 2 specific type */
  74         u8                      cookie[8];      /* optional cookie */
  75         int                     cookie_len;     /* 0, 4 or 8 bytes */
  76         u8                      peer_cookie[8]; /* peer's cookie */
  77         int                     peer_cookie_len; /* 0, 4 or 8 bytes */
  78         int                     reorder_timeout; /* configured reorder timeout
  79                                                   * (in jiffies) */
  80         int                     mtu;
  81         int                     mru;
  82         char                    *ifname;
  83 };
  84
  85 struct l2tp_session {
  86         int                     magic;          /* should be
  87                                                  * L2TP_SESSION_MAGIC */
  88
  89         struct l2tp_tunnel      *tunnel;        /* back pointer to tunnel
  90                                                  * context */
  91         u32                     session_id;
  92         u32                     peer_session_id;
  93         u8                      cookie[8];
  94         int                     cookie_len;
  95         u8                      peer_cookie[8];
  96         int                     peer_cookie_len;
  97         u16                     offset;         /* offset from end of L2TP header
  98                                                    to beginning of data */
  99         u16                     l2specific_len;
 100         u16                     l2specific_type;
 101         u16                     hdr_len;
 102         u32                     nr;             /* session NR state (receive) */
 103         u32                     ns;             /* session NR state (send) */
 104         struct sk_buff_head     reorder_q;      /* receive reorder queue */
 105         u32                     nr_max;         /* max NR. Depends on tunnel */
 106         u32                     nr_window_size; /* NR window size */
 107         u32                     nr_oos;         /* NR of last OOS packet */
 108         int                     nr_oos_count;   /* For OOS recovery */
 109         int                     nr_oos_count_max;
 110         struct hlist_node       hlist;          /* Hash list node */
 111         atomic_t                ref_count;
 112
 113         char                    name[32];       /* for logging */
 114         char                    ifname[IFNAMSIZ];
 115         unsigned int            data_seq:2;     /* data sequencing level
 116                                                  * 0 => none, 1 => IP only,
 117                                                  * 2 => all
 118                                                  */
 119         unsigned int            recv_seq:1;     /* expect receive packets with
 120                                                  * sequence numbers? */
 121         unsigned int            send_seq:1;     /* send packets with sequence
 122                                                  * numbers? */
 123         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
 124                                                  * sequence numbers under
 125                                                  * control of LNS. */
 126         int                     debug;          /* bitmask of debug message
 127                                                  * categories */
 128         int                     reorder_timeout; /* configured reorder timeout
 129                                                   * (in jiffies) */
 130         int                     reorder_skip;   /* set if skip to next nr */
 131         int                     mtu;
 132         int                     mru;
 133         enum l2tp_pwtype        pwtype;
 134         struct l2tp_stats       stats;
 135         struct hlist_node       global_hlist;   /* Global hash list node */
 136
 137         int (*build_header)(struct l2tp_session *session, void *buf);
 138         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 139         void (*session_close)(struct l2tp_session *session);
 140         void (*ref)(struct l2tp_session *session);
 141         void (*deref)(struct l2tp_session *session);
 142 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 143         void (*show)(struct seq_file *m, void *priv);
 144 #endif
 145         uint8_t                 priv[0];        /* private data */
 146 };
 147
 148 /* Describes the tunnel. It contains info to track all the associated
 149  * sessions so incoming packets can be sorted out
 150  */
 151 struct l2tp_tunnel_cfg {
 152         int                     debug;          /* bitmask of debug message
 153                                                  * categories */
 154         enum l2tp_encap_type    encap;
 155
 156         /* Used only for kernel-created sockets */
 157         struct in_addr          local_ip;
 158         struct in_addr          peer_ip;
 159 #if IS_ENABLED(CONFIG_IPV6)
 160         struct in6_addr         *local_ip6;
 161         struct in6_addr         *peer_ip6;
 162 #endif
 163         u16                     local_udp_port;
 164         u16                     peer_udp_port;
 165         unsigned int            use_udp_checksums:1,
 166                                 udp6_zero_tx_checksums:1,
 167                                 udp6_zero_rx_checksums:1;
 168 };
 169
 170 struct l2tp_tunnel {
 171         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 172         struct rcu_head rcu;
 173         rwlock_t                hlist_lock;     /* protect session_hlist */
 174         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 175                                                 /* hashed list of sessions,
 176                                                  * hashed by id */
 177         u32                     tunnel_id;
 178         u32                     peer_tunnel_id;
 179         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 180
 181         char                    name[20];       /* for logging */
 182         int                     debug;          /* bitmask of debug message
 183                                                  * categories */
 184         enum l2tp_encap_type    encap;
 185         struct l2tp_stats       stats;
 186
 187         struct list_head        list;           /* Keep a list of all tunnels */
 188         struct net              *l2tp_net;      /* the net we belong to */
 189
 190         atomic_t                ref_count;
 191 #ifdef CONFIG_DEBUG_FS
 192         void (*show)(struct seq_file *m, void *arg);
 193 #endif
 194         int (*recv_payload_hook)(struct sk_buff *skb);
 195         void (*old_sk_destruct)(struct sock *);
 196         struct sock             *sock;          /* Parent socket */
 197         int                     fd;             /* Parent fd, if tunnel socket
 198                                                  * was created by userspace */
 199 #if IS_ENABLED(CONFIG_IPV6)
 200         bool                    v4mapped;
 201 #endif
 202
 203         struct work_struct      del_work;
 204
 205         uint8_t                 priv[0];        /* private data */
 206 };
 207
 208 struct l2tp_nl_cmd_ops {
 209         int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
 210         int (*session_delete)(struct l2tp_session *session);
 211 };
 212
 213 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 214 {
 215         return &tunnel->priv[0];
 216 }
 217
 218 static inline void *l2tp_session_priv(struct l2tp_session *session)
 219 {
 220         return &session->priv[0];
 221 }
 222
 223 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 224 {
 225         struct l2tp_tunnel *tunnel;
 226
 227         if (sk == NULL)
 228                 return NULL;
 229
 230         sock_hold(sk);
 231         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 232         if (tunnel == NULL) {
 233                 sock_put(sk);
 234                 goto out;
 235         }
 236
 237         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 238
 239 out:
 240         return tunnel;
 241 }
 242
 243 struct l2tp_session *l2tp_session_find(struct net *net,
 244                                        struct l2tp_tunnel *tunnel,
 245                                        u32 session_id);
 246 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
 247 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
 248 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 249 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 250
 251 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
 252                        u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
 253                        struct l2tp_tunnel **tunnelp);
 254 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 255 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 256 struct l2tp_session *l2tp_session_create(int priv_size,
 257                                          struct l2tp_tunnel *tunnel,
 258                                          u32 session_id, u32 peer_session_id,
 259                                          struct l2tp_session_cfg *cfg);
 260 void __l2tp_session_unhash(struct l2tp_session *session);
 261 int l2tp_session_delete(struct l2tp_session *session);
 262 void l2tp_session_free(struct l2tp_session *session);
 263 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 264                       unsigned char *ptr, unsigned char *optr, u16 hdrflags,
 265                       int length, int (*payload_hook)(struct sk_buff *skb));
 266 int l2tp_session_queue_purge(struct l2tp_session *session);
 267 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 268 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 269
 270 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
 271                   int hdr_len);
 272
 273 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
 274                          const struct l2tp_nl_cmd_ops *ops);
 275 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 276
 277 /* Session reference counts. Incremented when code obtains a reference
 278  * to a session.
 279  */
 280 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 281 {
 282         atomic_inc(&session->ref_count);
 283 }
 284
 285 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
 286 {
 287         if (atomic_dec_and_test(&session->ref_count))
 288                 l2tp_session_free(session);
 289 }
 290
 291 #ifdef L2TP_REFCNT_DEBUG
 292 #define l2tp_session_inc_refcount(_s)                                   \
 293 do {                                                                    \
 294         pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",       \
 295                  __func__, __LINE__, (_s)->name,                        \
 296                  atomic_read(&_s->ref_count));                          \
 297         l2tp_session_inc_refcount_1(_s);                                \
 298 } while (0)
 299 #define l2tp_session_dec_refcount(_s)                                   \
 300 do {                                                                    \
 301         pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",       \
 302                  __func__, __LINE__, (_s)->name,                        \
 303                  atomic_read(&_s->ref_count));                          \
 304         l2tp_session_dec_refcount_1(_s);                                \
 305 } while (0)
 306 #else
 307 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
 308 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
 309 #endif
 310
 311 #define l2tp_printk(ptr, type, func, fmt, ...)                          \
 312 do {                                                                    \
 313         if (((ptr)->debug) & (type))                                    \
 314                 func(fmt, ##__VA_ARGS__);                               \
 315 } while (0)
 316
 317 #define l2tp_warn(ptr, type, fmt, ...)                                  \
 318         l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
 319 #define l2tp_info(ptr, type, fmt, ...)                                  \
 320         l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
 321 #define l2tp_dbg(ptr, type, fmt, ...)                                   \
 322         l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
 323
 324 #endif /* _L2TP_CORE_H_ */