LXR linux/net/l2tp/l2tp

   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 */
  27enum {
  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
  36struct sk_buff;
  37
  38struct 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
  50struct l2tp_tunnel;
  51
  52/* Describes a session. Contains information to determine incoming
  53 * packets and transmit outgoing ones.
  54 */
  55struct 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
  85struct 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#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 137        void (*show)(struct seq_file *m, void *priv);
 138#endif
 139        uint8_t                 priv[0];        /* private data */
 140};
 141
 142/* Describes the tunnel. It contains info to track all the associated
 143 * sessions so incoming packets can be sorted out
 144 */
 145struct l2tp_tunnel_cfg {
 146        int                     debug;          /* bitmask of debug message
 147                                                 * categories */
 148        enum l2tp_encap_type    encap;
 149
 150        /* Used only for kernel-created sockets */
 151        struct in_addr          local_ip;
 152        struct in_addr          peer_ip;
 153        u16                     local_udp_port;
 154        u16                     peer_udp_port;
 155        unsigned int            use_udp_checksums:1;
 156};
 157
 158struct l2tp_tunnel {
 159        int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 160        rwlock_t                hlist_lock;     /* protect session_hlist */
 161        struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 162                                                /* hashed list of sessions,
 163                                                 * hashed by id */
 164        u32                     tunnel_id;
 165        u32                     peer_tunnel_id;
 166        int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 167
 168        char                    name[20];       /* for logging */
 169        int                     debug;          /* bitmask of debug message
 170                                                 * categories */
 171        enum l2tp_encap_type    encap;
 172        struct l2tp_stats       stats;
 173
 174        struct list_head        list;           /* Keep a list of all tunnels */
 175        struct net              *l2tp_net;      /* the net we belong to */
 176
 177        atomic_t                ref_count;
 178#ifdef CONFIG_DEBUG_FS
 179        void (*show)(struct seq_file *m, void *arg);
 180#endif
 181        int (*recv_payload_hook)(struct sk_buff *skb);
 182        void (*old_sk_destruct)(struct sock *);
 183        struct sock             *sock;          /* Parent socket */
 184        int                     fd;
 185
 186        uint8_t                 priv[0];        /* private data */
 187};
 188
 189struct l2tp_nl_cmd_ops {
 190        int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
 191        int (*session_delete)(struct l2tp_session *session);
 192};
 193
 194static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 195{
 196        return &tunnel->priv[0];
 197}
 198
 199static inline void *l2tp_session_priv(struct l2tp_session *session)
 200{
 201        return &session->priv[0];
 202}
 203
 204static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 205{
 206        struct l2tp_tunnel *tunnel;
 207
 208        if (sk == NULL)
 209                return NULL;
 210
 211        sock_hold(sk);
 212        tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 213        if (tunnel == NULL) {
 214                sock_put(sk);
 215                goto out;
 216        }
 217
 218        BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 219
 220out:
 221        return tunnel;
 222}
 223
 224extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
 225extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
 226extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
 227extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 228extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 229
 230extern 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);
 231extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 232extern 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);
 233extern int l2tp_session_delete(struct l2tp_session *session);
 234extern void l2tp_session_free(struct l2tp_session *session);
 235extern 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));
 236extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 237
 238extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
 239
 240extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
 241extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 242
 243/* Session reference counts. Incremented when code obtains a reference
 244 * to a session.
 245 */
 246static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 247{
 248        atomic_inc(&session->ref_count);
 249}
 250
 251static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
 252{
 253        if (atomic_dec_and_test(&session->ref_count))
 254                l2tp_session_free(session);
 255}
 256
 257#ifdef L2TP_REFCNT_DEBUG
 258#define l2tp_session_inc_refcount(_s) do { \
 259                printk(KERN_DEBUG "l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
 260                l2tp_session_inc_refcount_1(_s);                                \
 261        } while (0)
 262#define l2tp_session_dec_refcount(_s) do { \
 263                printk(KERN_DEBUG "l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_s)->name, atomic_read(&_s->ref_count)); \
 264                l2tp_session_dec_refcount_1(_s);                                \
 265        } while (0)
 266#else
 267#define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
 268#define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
 269#endif
 270
 271#endif /* _L2TP_CORE_H_ */
 272