Pileus Git - ~andy/linux/blob - 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 enum l2tp_pwtype {
  37         L2TP_PWTYPE_NONE = 0x0000,
  38         L2TP_PWTYPE_ETH_VLAN = 0x0004,
  39         L2TP_PWTYPE_ETH = 0x0005,
  40         L2TP_PWTYPE_PPP = 0x0007,
  41         L2TP_PWTYPE_PPP_AC = 0x0008,
  42         L2TP_PWTYPE_IP = 0x000b,
  43         __L2TP_PWTYPE_MAX
  44 };
  45
  46 enum l2tp_l2spec_type {
  47         L2TP_L2SPECTYPE_NONE,
  48         L2TP_L2SPECTYPE_DEFAULT,
  49 };
  50
  51 struct sk_buff;
  52
  53 struct l2tp_stats {
  54         u64                     tx_packets;
  55         u64                     tx_bytes;
  56         u64                     tx_errors;
  57         u64                     rx_packets;
  58         u64                     rx_bytes;
  59         u64                     rx_seq_discards;
  60         u64                     rx_oos_packets;
  61         u64                     rx_errors;
  62         u64                     rx_cookie_discards;
  63 };
  64
  65 struct l2tp_tunnel;
  66
  67 /* Describes a session. Contains information to determine incoming
  68  * packets and transmit outgoing ones.
  69  */
  70 struct l2tp_session_cfg {
  71         enum l2tp_pwtype        pw_type;
  72         unsigned                data_seq:2;     /* data sequencing level
  73                                                  * 0 => none, 1 => IP only,
  74                                                  * 2 => all
  75                                                  */
  76         unsigned                recv_seq:1;     /* expect receive packets with
  77                                                  * sequence numbers? */
  78         unsigned                send_seq:1;     /* send packets with sequence
  79                                                  * numbers? */
  80         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
  81                                                  * sequence numbers under
  82                                                  * control of LNS. */
  83         int                     debug;          /* bitmask of debug message
  84                                                  * categories */
  85         u16                     offset;         /* offset to payload */
  86         u16                     l2specific_len; /* Layer 2 specific length */
  87         u16                     l2specific_type; /* Layer 2 specific type */
  88         u8                      cookie[8];      /* optional cookie */
  89         int                     cookie_len;     /* 0, 4 or 8 bytes */
  90         u8                      peer_cookie[8]; /* peer's cookie */
  91         int                     peer_cookie_len; /* 0, 4 or 8 bytes */
  92         int                     reorder_timeout; /* configured reorder timeout
  93                                                   * (in jiffies) */
  94         int                     mtu;
  95         int                     mru;
  96 };
  97
  98 struct l2tp_session {
  99         int                     magic;          /* should be
 100                                                  * L2TP_SESSION_MAGIC */
 101
 102         struct l2tp_tunnel      *tunnel;        /* back pointer to tunnel
 103                                                  * context */
 104         u32                     session_id;
 105         u32                     peer_session_id;
 106         u8                      cookie[8];
 107         int                     cookie_len;
 108         u8                      peer_cookie[8];
 109         int                     peer_cookie_len;
 110         u16                     offset;         /* offset from end of L2TP header
 111                                                    to beginning of data */
 112         u16                     l2specific_len;
 113         u16                     l2specific_type;
 114         u16                     hdr_len;
 115         u32                     nr;             /* session NR state (receive) */
 116         u32                     ns;             /* session NR state (send) */
 117         struct sk_buff_head     reorder_q;      /* receive reorder queue */
 118         struct hlist_node       hlist;          /* Hash list node */
 119         atomic_t                ref_count;
 120
 121         char                    name[32];       /* for logging */
 122         unsigned                data_seq:2;     /* data sequencing level
 123                                                  * 0 => none, 1 => IP only,
 124                                                  * 2 => all
 125                                                  */
 126         unsigned                recv_seq:1;     /* expect receive packets with
 127                                                  * sequence numbers? */
 128         unsigned                send_seq:1;     /* send packets with sequence
 129                                                  * numbers? */
 130         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
 131                                                  * sequence numbers under
 132                                                  * control of LNS. */
 133         int                     debug;          /* bitmask of debug message
 134                                                  * categories */
 135         int                     reorder_timeout; /* configured reorder timeout
 136                                                   * (in jiffies) */
 137         int                     mtu;
 138         int                     mru;
 139         enum l2tp_pwtype        pwtype;
 140         struct l2tp_stats       stats;
 141         struct hlist_node       global_hlist;   /* Global hash list node */
 142
 143         int (*build_header)(struct l2tp_session *session, void *buf);
 144         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 145         void (*session_close)(struct l2tp_session *session);
 146         void (*ref)(struct l2tp_session *session);
 147         void (*deref)(struct l2tp_session *session);
 148
 149         uint8_t                 priv[0];        /* private data */
 150 };
 151
 152 /* Describes the tunnel. It contains info to track all the associated
 153  * sessions so incoming packets can be sorted out
 154  */
 155 struct l2tp_tunnel_cfg {
 156         int                     debug;          /* bitmask of debug message
 157                                                  * categories */
 158 };
 159
 160 struct l2tp_tunnel {
 161         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 162         rwlock_t                hlist_lock;     /* protect session_hlist */
 163         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 164                                                 /* hashed list of sessions,
 165                                                  * hashed by id */
 166         u32                     tunnel_id;
 167         u32                     peer_tunnel_id;
 168         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 169
 170         char                    name[20];       /* for logging */
 171         int                     debug;          /* bitmask of debug message
 172                                                  * categories */
 173         struct l2tp_stats       stats;
 174
 175         struct list_head        list;           /* Keep a list of all tunnels */
 176         struct net              *l2tp_net;      /* the net we belong to */
 177
 178         atomic_t                ref_count;
 179
 180         int (*recv_payload_hook)(struct sk_buff *skb);
 181         void (*old_sk_destruct)(struct sock *);
 182         struct sock             *sock;          /* Parent socket */
 183         int                     fd;
 184
 185         uint8_t                 priv[0];        /* private data */
 186 };
 187
 188 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 189 {
 190         return &tunnel->priv[0];
 191 }
 192
 193 static inline void *l2tp_session_priv(struct l2tp_session *session)
 194 {
 195         return &session->priv[0];
 196 }
 197
 198 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 199 {
 200         struct l2tp_tunnel *tunnel;
 201
 202         if (sk == NULL)
 203                 return NULL;
 204
 205         sock_hold(sk);
 206         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 207         if (tunnel == NULL) {
 208                 sock_put(sk);
 209                 goto out;
 210         }
 211
 212         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 213
 214 out:
 215         return tunnel;
 216 }
 217
 218 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
 219 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
 220 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 221 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 222
 223 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);
 224 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);
 225 extern void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
 226 extern void l2tp_session_free(struct l2tp_session *session);
 227 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));
 228 extern int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, int (*payload_hook)(struct sk_buff *skb));
 229 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 230
 231 extern int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len);
 232 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
 233 extern void l2tp_tunnel_destruct(struct sock *sk);
 234 extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 235 extern void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 236
 237 /* Tunnel reference counts. Incremented per session that is added to
 238  * the tunnel.
 239  */
 240 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
 241 {
 242         atomic_inc(&tunnel->ref_count);
 243 }
 244
 245 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
 246 {
 247         if (atomic_dec_and_test(&tunnel->ref_count))
 248                 l2tp_tunnel_free(tunnel);
 249 }
 250 #ifdef L2TP_REFCNT_DEBUG
 251 #define l2tp_tunnel_inc_refcount(_t) do { \
 252                 printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
 253                 l2tp_tunnel_inc_refcount_1(_t);                         \
 254         } while (0)
 255 #define l2tp_tunnel_dec_refcount(_t) do { \
 256                 printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
 257                 l2tp_tunnel_dec_refcount_1(_t);                         \
 258         } while (0)
 259 #else
 260 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
 261 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
 262 #endif
 263
 264 /* Session reference counts. Incremented when code obtains a reference
 265  * to a session.
 266  */
 267 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 268 {
 269         atomic_inc(&session->ref_count);
 270 }
 271
 272 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
 273 {
 274         if (atomic_dec_and_test(&session->ref_count))
 275                 l2tp_session_free(session);
 276 }
 277
 278 #ifdef L2TP_REFCNT_DEBUG
 279 #define l2tp_session_inc_refcount(_s) do { \
 280                 printk(KERN_DEBUG "l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
 281                 l2tp_session_inc_refcount_1(_s);                                \
 282         } while (0)
 283 #define l2tp_session_dec_refcount(_s) do { \
 284                 printk(KERN_DEBUG "l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
 285                 l2tp_session_dec_refcount_1(_s);                                \
 286         } while (0)
 287 #else
 288 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
 289 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
 290 #endif
 291
 292 #endif /* _L2TP_CORE_H_ */