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   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         u64                     tx_packets;
  40         u64                     tx_bytes;
  41         u64                     tx_errors;
  42         u64                     rx_packets;
  43         u64                     rx_bytes;
  44         u64                     rx_seq_discards;
  45         u64                     rx_oos_packets;
  46         u64                     rx_errors;
  47         u64                     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                data_seq:2;     /* data sequencing level
  58                                                  * 0 => none, 1 => IP only,
  59                                                  * 2 => all
  60                                                  */
  61         unsigned                recv_seq:1;     /* expect receive packets with
  62                                                  * sequence numbers? */
  63         unsigned                send_seq:1;     /* send packets with sequence
  64                                                  * numbers? */
  65         unsigned                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         struct hlist_node       hlist;          /* Hash list node */
 106         atomic_t                ref_count;
 107
 108         char                    name[32];       /* for logging */
 109         char                    ifname[IFNAMSIZ];
 110         unsigned                data_seq:2;     /* data sequencing level
 111                                                  * 0 => none, 1 => IP only,
 112                                                  * 2 => all
 113                                                  */
 114         unsigned                recv_seq:1;     /* expect receive packets with
 115                                                  * sequence numbers? */
 116         unsigned                send_seq:1;     /* send packets with sequence
 117                                                  * numbers? */
 118         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
 119                                                  * sequence numbers under
 120                                                  * control of LNS. */
 121         int                     debug;          /* bitmask of debug message
 122                                                  * categories */
 123         int                     reorder_timeout; /* configured reorder timeout
 124                                                   * (in jiffies) */
 125         int                     mtu;
 126         int                     mru;
 127         enum l2tp_pwtype        pwtype;
 128         struct l2tp_stats       stats;
 129         struct hlist_node       global_hlist;   /* Global hash list node */
 130
 131         int (*build_header)(struct l2tp_session *session, void *buf);
 132         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 133         void (*session_close)(struct l2tp_session *session);
 134         void (*ref)(struct l2tp_session *session);
 135         void (*deref)(struct l2tp_session *session);
 136
 137         uint8_t                 priv[0];        /* private data */
 138 };
 139
 140 /* Describes the tunnel. It contains info to track all the associated
 141  * sessions so incoming packets can be sorted out
 142  */
 143 struct l2tp_tunnel_cfg {
 144         int                     debug;          /* bitmask of debug message
 145                                                  * categories */
 146         enum l2tp_encap_type    encap;
 147 };
 148
 149 struct l2tp_tunnel {
 150         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 151         rwlock_t                hlist_lock;     /* protect session_hlist */
 152         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 153                                                 /* hashed list of sessions,
 154                                                  * hashed by id */
 155         u32                     tunnel_id;
 156         u32                     peer_tunnel_id;
 157         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 158
 159         char                    name[20];       /* for logging */
 160         int                     debug;          /* bitmask of debug message
 161                                                  * categories */
 162         enum l2tp_encap_type    encap;
 163         struct l2tp_stats       stats;
 164
 165         struct list_head        list;           /* Keep a list of all tunnels */
 166         struct net              *l2tp_net;      /* the net we belong to */
 167
 168         atomic_t                ref_count;
 169
 170         int (*recv_payload_hook)(struct sk_buff *skb);
 171         void (*old_sk_destruct)(struct sock *);
 172         struct sock             *sock;          /* Parent socket */
 173         int                     fd;
 174
 175         uint8_t                 priv[0];        /* private data */
 176 };
 177
 178 struct l2tp_nl_cmd_ops {
 179         int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
 180         int (*session_delete)(struct l2tp_session *session);
 181 };
 182
 183 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 184 {
 185         return &tunnel->priv[0];
 186 }
 187
 188 static inline void *l2tp_session_priv(struct l2tp_session *session)
 189 {
 190         return &session->priv[0];
 191 }
 192
 193 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 194 {
 195         struct l2tp_tunnel *tunnel;
 196
 197         if (sk == NULL)
 198                 return NULL;
 199
 200         sock_hold(sk);
 201         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 202         if (tunnel == NULL) {
 203                 sock_put(sk);
 204                 goto out;
 205         }
 206
 207         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 208
 209 out:
 210         return tunnel;
 211 }
 212
 213 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
 214 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
 215 extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
 216 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 217 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 218
 219 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);
 220 extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 221 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);
 222 extern int l2tp_session_delete(struct l2tp_session *session);
 223 extern void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
 224 extern void l2tp_session_free(struct l2tp_session *session);
 225 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));
 226 extern int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, int (*payload_hook)(struct sk_buff *skb));
 227 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 228
 229 extern int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len);
 230 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
 231 extern void l2tp_tunnel_destruct(struct sock *sk);
 232 extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 233 extern void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 234
 235 extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
 236 extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 237
 238 /* Tunnel reference counts. Incremented per session that is added to
 239  * the tunnel.
 240  */
 241 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
 242 {
 243         atomic_inc(&tunnel->ref_count);
 244 }
 245
 246 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
 247 {
 248         if (atomic_dec_and_test(&tunnel->ref_count))
 249                 l2tp_tunnel_free(tunnel);
 250 }
 251 #ifdef L2TP_REFCNT_DEBUG
 252 #define l2tp_tunnel_inc_refcount(_t) do { \
 253                 printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
 254                 l2tp_tunnel_inc_refcount_1(_t);                         \
 255         } while (0)
 256 #define l2tp_tunnel_dec_refcount(_t) do { \
 257                 printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
 258                 l2tp_tunnel_dec_refcount_1(_t);                         \
 259         } while (0)
 260 #else
 261 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
 262 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
 263 #endif
 264
 265 /* Session reference counts. Incremented when code obtains a reference
 266  * to a session.
 267  */
 268 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 269 {
 270         atomic_inc(&session->ref_count);
 271 }
 272
 273 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
 274 {
 275         if (atomic_dec_and_test(&session->ref_count))
 276                 l2tp_session_free(session);
 277 }
 278
 279 #ifdef L2TP_REFCNT_DEBUG
 280 #define l2tp_session_inc_refcount(_s) do { \
 281                 printk(KERN_DEBUG "l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
 282                 l2tp_session_inc_refcount_1(_s);                                \
 283         } while (0)
 284 #define l2tp_session_dec_refcount(_s) do { \
 285                 printk(KERN_DEBUG "l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
 286                 l2tp_session_dec_refcount_1(_s);                                \
 287         } while (0)
 288 #else
 289 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
 290 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
 291 #endif
 292
 293 #endif /* _L2TP_CORE_H_ */