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        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
  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 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
  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        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 */
 151struct 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
 170struct 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
 208struct 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
 213static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 214{
 215        return &tunnel->priv[0];
 216}
 217
 218static inline void *l2tp_session_priv(struct l2tp_session *session)
 219{
 220        return &session->priv[0];
 221}
 222
 223static 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
 239out:
 240        return tunnel;
 241}
 242
 243struct l2tp_session *l2tp_session_find(struct net *net,
 244                                       struct l2tp_tunnel *tunnel,
 245                                       u32 session_id);
 246struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
 247struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
 248struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 249struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 250
 251int 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);
 254void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 255int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 256struct 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);
 260void __l2tp_session_unhash(struct l2tp_session *session);
 261int l2tp_session_delete(struct l2tp_session *session);
 262void l2tp_session_free(struct l2tp_session *session);
 263void 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));
 266int l2tp_session_queue_purge(struct l2tp_session *session);
 267int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 268void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 269
 270int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
 271                  int hdr_len);
 272
 273int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
 274                         const struct l2tp_nl_cmd_ops *ops);
 275void 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 */
 280static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 281{
 282        atomic_inc(&session->ref_count);
 283}
 284
 285static 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)                                   \
 293do {                                                                    \
 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)                                   \
 300do {                                                                    \
 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, ...)                          \
 312do {                                                                    \
 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_ */
 325