linux/net/l2tp/l2tp_core.h
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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 */
  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        struct u64_stats_sync   syncp;
  49};
  50
  51struct l2tp_tunnel;
  52
  53/* Describes a session. Contains information to determine incoming
  54 * packets and transmit outgoing ones.
  55 */
  56struct l2tp_session_cfg {
  57        enum l2tp_pwtype        pw_type;
  58        unsigned int            data_seq:2;     /* data sequencing level
  59                                                 * 0 => none, 1 => IP only,
  60                                                 * 2 => all
  61                                                 */
  62        unsigned int            recv_seq:1;     /* expect receive packets with
  63                                                 * sequence numbers? */
  64        unsigned int            send_seq:1;     /* send packets with sequence
  65                                                 * numbers? */
  66        unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
  67                                                 * sequence numbers under
  68                                                 * control of LNS. */
  69        int                     debug;          /* bitmask of debug message
  70                                                 * categories */
  71        u16                     vlan_id;        /* VLAN pseudowire only */
  72        u16                     offset;         /* offset to payload */
  73        u16                     l2specific_len; /* Layer 2 specific length */
  74        u16                     l2specific_type; /* Layer 2 specific type */
  75        u8                      cookie[8];      /* optional cookie */
  76        int                     cookie_len;     /* 0, 4 or 8 bytes */
  77        u8                      peer_cookie[8]; /* peer's cookie */
  78        int                     peer_cookie_len; /* 0, 4 or 8 bytes */
  79        int                     reorder_timeout; /* configured reorder timeout
  80                                                  * (in jiffies) */
  81        int                     mtu;
  82        int                     mru;
  83        char                    *ifname;
  84};
  85
  86struct l2tp_session {
  87        int                     magic;          /* should be
  88                                                 * L2TP_SESSION_MAGIC */
  89
  90        struct l2tp_tunnel      *tunnel;        /* back pointer to tunnel
  91                                                 * context */
  92        u32                     session_id;
  93        u32                     peer_session_id;
  94        u8                      cookie[8];
  95        int                     cookie_len;
  96        u8                      peer_cookie[8];
  97        int                     peer_cookie_len;
  98        u16                     offset;         /* offset from end of L2TP header
  99                                                   to beginning of data */
 100        u16                     l2specific_len;
 101        u16                     l2specific_type;
 102        u16                     hdr_len;
 103        u32                     nr;             /* session NR state (receive) */
 104        u32                     ns;             /* session NR state (send) */
 105        struct sk_buff_head     reorder_q;      /* receive reorder queue */
 106        struct hlist_node       hlist;          /* Hash list node */
 107        atomic_t                ref_count;
 108
 109        char                    name[32];       /* for logging */
 110        char                    ifname[IFNAMSIZ];
 111        unsigned int            data_seq:2;     /* data sequencing level
 112                                                 * 0 => none, 1 => IP only,
 113                                                 * 2 => all
 114                                                 */
 115        unsigned int            recv_seq:1;     /* expect receive packets with
 116                                                 * sequence numbers? */
 117        unsigned int            send_seq:1;     /* send packets with sequence
 118                                                 * numbers? */
 119        unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
 120                                                 * sequence numbers under
 121                                                 * control of LNS. */
 122        int                     debug;          /* bitmask of debug message
 123                                                 * categories */
 124        int                     reorder_timeout; /* configured reorder timeout
 125                                                  * (in jiffies) */
 126        int                     reorder_skip;   /* set if skip to next nr */
 127        int                     mtu;
 128        int                     mru;
 129        enum l2tp_pwtype        pwtype;
 130        struct l2tp_stats       stats;
 131        struct hlist_node       global_hlist;   /* Global hash list node */
 132
 133        int (*build_header)(struct l2tp_session *session, void *buf);
 134        void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 135        void (*session_close)(struct l2tp_session *session);
 136        void (*ref)(struct l2tp_session *session);
 137        void (*deref)(struct l2tp_session *session);
 138#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 139        void (*show)(struct seq_file *m, void *priv);
 140#endif
 141        uint8_t                 priv[0];        /* private data */
 142};
 143
 144/* Describes the tunnel. It contains info to track all the associated
 145 * sessions so incoming packets can be sorted out
 146 */
 147struct l2tp_tunnel_cfg {
 148        int                     debug;          /* bitmask of debug message
 149                                                 * categories */
 150        enum l2tp_encap_type    encap;
 151
 152        /* Used only for kernel-created sockets */
 153        struct in_addr          local_ip;
 154        struct in_addr          peer_ip;
 155#if IS_ENABLED(CONFIG_IPV6)
 156        struct in6_addr         *local_ip6;
 157        struct in6_addr         *peer_ip6;
 158#endif
 159        u16                     local_udp_port;
 160        u16                     peer_udp_port;
 161        unsigned int            use_udp_checksums:1;
 162};
 163
 164struct l2tp_tunnel {
 165        int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 166        struct rcu_head rcu;
 167        rwlock_t                hlist_lock;     /* protect session_hlist */
 168        struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 169                                                /* hashed list of sessions,
 170                                                 * hashed by id */
 171        u32                     tunnel_id;
 172        u32                     peer_tunnel_id;
 173        int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 174
 175        char                    name[20];       /* for logging */
 176        int                     debug;          /* bitmask of debug message
 177                                                 * categories */
 178        enum l2tp_encap_type    encap;
 179        struct l2tp_stats       stats;
 180
 181        struct list_head        list;           /* Keep a list of all tunnels */
 182        struct net              *l2tp_net;      /* the net we belong to */
 183
 184        atomic_t                ref_count;
 185#ifdef CONFIG_DEBUG_FS
 186        void (*show)(struct seq_file *m, void *arg);
 187#endif
 188        int (*recv_payload_hook)(struct sk_buff *skb);
 189        void (*old_sk_destruct)(struct sock *);
 190        struct sock             *sock;          /* Parent socket */
 191        int                     fd;             /* Parent fd, if tunnel socket
 192                                                 * was created by userspace */
 193
 194        uint8_t                 priv[0];        /* private data */
 195};
 196
 197struct l2tp_nl_cmd_ops {
 198        int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
 199        int (*session_delete)(struct l2tp_session *session);
 200};
 201
 202static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 203{
 204        return &tunnel->priv[0];
 205}
 206
 207static inline void *l2tp_session_priv(struct l2tp_session *session)
 208{
 209        return &session->priv[0];
 210}
 211
 212static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 213{
 214        struct l2tp_tunnel *tunnel;
 215
 216        if (sk == NULL)
 217                return NULL;
 218
 219        sock_hold(sk);
 220        tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 221        if (tunnel == NULL) {
 222                sock_put(sk);
 223                goto out;
 224        }
 225
 226        BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 227
 228out:
 229        return tunnel;
 230}
 231
 232extern struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel);
 233extern void l2tp_tunnel_sock_put(struct sock *sk);
 234extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
 235extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
 236extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
 237extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 238extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 239
 240extern 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);
 241extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 242extern 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);
 243extern int l2tp_session_delete(struct l2tp_session *session);
 244extern void l2tp_session_free(struct l2tp_session *session);
 245extern 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));
 246extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 247
 248extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
 249
 250extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
 251extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 252
 253/* Session reference counts. Incremented when code obtains a reference
 254 * to a session.
 255 */
 256static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 257{
 258        atomic_inc(&session->ref_count);
 259}
 260
 261static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
 262{
 263        if (atomic_dec_and_test(&session->ref_count))
 264                l2tp_session_free(session);
 265}
 266
 267#ifdef L2TP_REFCNT_DEBUG
 268#define l2tp_session_inc_refcount(_s)                                   \
 269do {                                                                    \
 270        pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",       \
 271                 __func__, __LINE__, (_s)->name,                        \
 272                 atomic_read(&_s->ref_count));                          \
 273        l2tp_session_inc_refcount_1(_s);                                \
 274} while (0)
 275#define l2tp_session_dec_refcount(_s)                                   \
 276do {                                                                    \
 277        pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",       \
 278                 __func__, __LINE__, (_s)->name,                        \
 279                 atomic_read(&_s->ref_count));                          \
 280        l2tp_session_dec_refcount_1(_s);                                \
 281} while (0)
 282#else
 283#define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
 284#define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
 285#endif
 286
 287#define l2tp_printk(ptr, type, func, fmt, ...)                          \
 288do {                                                                    \
 289        if (((ptr)->debug) & (type))                                    \
 290                func(fmt, ##__VA_ARGS__);                               \
 291} while (0)
 292
 293#define l2tp_warn(ptr, type, fmt, ...)                                  \
 294        l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
 295#define l2tp_info(ptr, type, fmt, ...)                                  \
 296        l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
 297#define l2tp_dbg(ptr, type, fmt, ...)                                   \
 298        l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
 299
 300#endif /* _L2TP_CORE_H_ */
 301
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