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 #include <linux/refcount.h>
  11
  12 #ifndef _L2TP_CORE_H_
  13 #define _L2TP_CORE_H_
  14
  15 /* Just some random numbers */
  16 #define L2TP_TUNNEL_MAGIC       0x42114DDA
  17 #define L2TP_SESSION_MAGIC      0x0C04EB7D
  18
  19 /* Per tunnel, session hash table size */
  20 #define L2TP_HASH_BITS  4
  21 #define L2TP_HASH_SIZE  (1 << L2TP_HASH_BITS)
  22
  23 /* System-wide, session hash table size */
  24 #define L2TP_HASH_BITS_2        8
  25 #define L2TP_HASH_SIZE_2        (1 << L2TP_HASH_BITS_2)
  26
  27 struct sk_buff;
  28
  29 struct l2tp_stats {
  30         atomic_long_t           tx_packets;
  31         atomic_long_t           tx_bytes;
  32         atomic_long_t           tx_errors;
  33         atomic_long_t           rx_packets;
  34         atomic_long_t           rx_bytes;
  35         atomic_long_t           rx_seq_discards;
  36         atomic_long_t           rx_oos_packets;
  37         atomic_long_t           rx_errors;
  38         atomic_long_t           rx_cookie_discards;
  39 };
  40
  41 struct l2tp_tunnel;
  42
  43 /* Describes a session. Contains information to determine incoming
  44  * packets and transmit outgoing ones.
  45  */
  46 struct l2tp_session_cfg {
  47         enum l2tp_pwtype        pw_type;
  48         unsigned int            data_seq:2;     /* data sequencing level
  49                                                  * 0 => none, 1 => IP only,
  50                                                  * 2 => all
  51                                                  */
  52         unsigned int            recv_seq:1;     /* expect receive packets with
  53                                                  * sequence numbers? */
  54         unsigned int            send_seq:1;     /* send packets with sequence
  55                                                  * numbers? */
  56         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
  57                                                  * sequence numbers under
  58                                                  * control of LNS. */
  59         int                     debug;          /* bitmask of debug message
  60                                                  * categories */
  61         u16                     vlan_id;        /* VLAN pseudowire only */
  62         u16                     offset;         /* offset to payload */
  63         u16                     l2specific_len; /* Layer 2 specific length */
  64         u16                     l2specific_type; /* Layer 2 specific type */
  65         u8                      cookie[8];      /* optional cookie */
  66         int                     cookie_len;     /* 0, 4 or 8 bytes */
  67         u8                      peer_cookie[8]; /* peer's cookie */
  68         int                     peer_cookie_len; /* 0, 4 or 8 bytes */
  69         int                     reorder_timeout; /* configured reorder timeout
  70                                                   * (in jiffies) */
  71         int                     mtu;
  72         int                     mru;
  73         char                    *ifname;
  74 };
  75
  76 struct l2tp_session {
  77         int                     magic;          /* should be
  78                                                  * L2TP_SESSION_MAGIC */
  79
  80         struct l2tp_tunnel      *tunnel;        /* back pointer to tunnel
  81                                                  * context */
  82         u32                     session_id;
  83         u32                     peer_session_id;
  84         u8                      cookie[8];
  85         int                     cookie_len;
  86         u8                      peer_cookie[8];
  87         int                     peer_cookie_len;
  88         u16                     offset;         /* offset from end of L2TP header
  89                                                    to beginning of data */
  90         u16                     l2specific_len;
  91         u16                     l2specific_type;
  92         u16                     hdr_len;
  93         u32                     nr;             /* session NR state (receive) */
  94         u32                     ns;             /* session NR state (send) */
  95         struct sk_buff_head     reorder_q;      /* receive reorder queue */
  96         u32                     nr_max;         /* max NR. Depends on tunnel */
  97         u32                     nr_window_size; /* NR window size */
  98         u32                     nr_oos;         /* NR of last OOS packet */
  99         int                     nr_oos_count;   /* For OOS recovery */
 100         int                     nr_oos_count_max;
 101         struct hlist_node       hlist;          /* Hash list node */
 102         refcount_t              ref_count;
 103
 104         char                    name[32];       /* for logging */
 105         char                    ifname[IFNAMSIZ];
 106         unsigned int            data_seq:2;     /* data sequencing level
 107                                                  * 0 => none, 1 => IP only,
 108                                                  * 2 => all
 109                                                  */
 110         unsigned int            recv_seq:1;     /* expect receive packets with
 111                                                  * sequence numbers? */
 112         unsigned int            send_seq:1;     /* send packets with sequence
 113                                                  * numbers? */
 114         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
 115                                                  * sequence numbers under
 116                                                  * control of LNS. */
 117         int                     debug;          /* bitmask of debug message
 118                                                  * categories */
 119         int                     reorder_timeout; /* configured reorder timeout
 120                                                   * (in jiffies) */
 121         int                     reorder_skip;   /* set if skip to next nr */
 122         int                     mtu;
 123         int                     mru;
 124         enum l2tp_pwtype        pwtype;
 125         struct l2tp_stats       stats;
 126         struct hlist_node       global_hlist;   /* Global hash list node */
 127
 128         int (*build_header)(struct l2tp_session *session, void *buf);
 129         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 130         void (*session_close)(struct l2tp_session *session);
 131         void (*ref)(struct l2tp_session *session);
 132         void (*deref)(struct l2tp_session *session);
 133 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 134         void (*show)(struct seq_file *m, void *priv);
 135 #endif
 136         uint8_t                 priv[0];        /* private data */
 137 };
 138
 139 /* Describes the tunnel. It contains info to track all the associated
 140  * sessions so incoming packets can be sorted out
 141  */
 142 struct l2tp_tunnel_cfg {
 143         int                     debug;          /* bitmask of debug message
 144                                                  * categories */
 145         enum l2tp_encap_type    encap;
 146
 147         /* Used only for kernel-created sockets */
 148         struct in_addr          local_ip;
 149         struct in_addr          peer_ip;
 150 #if IS_ENABLED(CONFIG_IPV6)
 151         struct in6_addr         *local_ip6;
 152         struct in6_addr         *peer_ip6;
 153 #endif
 154         u16                     local_udp_port;
 155         u16                     peer_udp_port;
 156         unsigned int            use_udp_checksums:1,
 157                                 udp6_zero_tx_checksums:1,
 158                                 udp6_zero_rx_checksums:1;
 159 };
 160
 161 struct l2tp_tunnel {
 162         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 163         struct rcu_head rcu;
 164         rwlock_t                hlist_lock;     /* protect session_hlist */
 165         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 166                                                 /* hashed list of sessions,
 167                                                  * hashed by id */
 168         u32                     tunnel_id;
 169         u32                     peer_tunnel_id;
 170         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 171
 172         char                    name[20];       /* for logging */
 173         int                     debug;          /* bitmask of debug message
 174                                                  * categories */
 175         enum l2tp_encap_type    encap;
 176         struct l2tp_stats       stats;
 177
 178         struct list_head        list;           /* Keep a list of all tunnels */
 179         struct net              *l2tp_net;      /* the net we belong to */
 180
 181         refcount_t              ref_count;
 182 #ifdef CONFIG_DEBUG_FS
 183         void (*show)(struct seq_file *m, void *arg);
 184 #endif
 185         int (*recv_payload_hook)(struct sk_buff *skb);
 186         void (*old_sk_destruct)(struct sock *);
 187         struct sock             *sock;          /* Parent socket */
 188         int                     fd;             /* Parent fd, if tunnel socket
 189                                                  * was created by userspace */
 190 #if IS_ENABLED(CONFIG_IPV6)
 191         bool                    v4mapped;
 192 #endif
 193
 194         struct work_struct      del_work;
 195
 196         uint8_t                 priv[0];        /* private data */
 197 };
 198
 199 struct l2tp_nl_cmd_ops {
 200         int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
 201         int (*session_delete)(struct l2tp_session *session);
 202 };
 203
 204 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 205 {
 206         return &tunnel->priv[0];
 207 }
 208
 209 static inline void *l2tp_session_priv(struct l2tp_session *session)
 210 {
 211         return &session->priv[0];
 212 }
 213
 214 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 215 {
 216         struct l2tp_tunnel *tunnel;
 217
 218         if (sk == NULL)
 219                 return NULL;
 220
 221         sock_hold(sk);
 222         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 223         if (tunnel == NULL) {
 224                 sock_put(sk);
 225                 goto out;
 226         }
 227
 228         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 229
 230 out:
 231         return tunnel;
 232 }
 233
 234 struct l2tp_session *l2tp_session_get(const struct net *net,
 235                                       struct l2tp_tunnel *tunnel,
 236                                       u32 session_id, bool do_ref);
 237 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
 238                                           bool do_ref);
 239 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
 240                                                 const char *ifname,
 241                                                 bool do_ref);
 242 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id);
 243 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
 244
 245 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
 246                        u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
 247                        struct l2tp_tunnel **tunnelp);
 248 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 249 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 250 struct l2tp_session *l2tp_session_create(int priv_size,
 251                                          struct l2tp_tunnel *tunnel,
 252                                          u32 session_id, u32 peer_session_id,
 253                                          struct l2tp_session_cfg *cfg);
 254 void __l2tp_session_unhash(struct l2tp_session *session);
 255 int l2tp_session_delete(struct l2tp_session *session);
 256 void l2tp_session_free(struct l2tp_session *session);
 257 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 258                       unsigned char *ptr, unsigned char *optr, u16 hdrflags,
 259                       int length, int (*payload_hook)(struct sk_buff *skb));
 260 int l2tp_session_queue_purge(struct l2tp_session *session);
 261 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 262 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 263
 264 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
 265                   int hdr_len);
 266
 267 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
 268                          const struct l2tp_nl_cmd_ops *ops);
 269 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 270 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 271
 272 /* Session reference counts. Incremented when code obtains a reference
 273  * to a session.
 274  */
 275 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 276 {
 277         refcount_inc(&session->ref_count);
 278 }
 279
 280 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
 281 {
 282         if (refcount_dec_and_test(&session->ref_count))
 283                 l2tp_session_free(session);
 284 }
 285
 286 #ifdef L2TP_REFCNT_DEBUG
 287 #define l2tp_session_inc_refcount(_s)                                   \
 288 do {                                                                    \
 289         pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",       \
 290                  __func__, __LINE__, (_s)->name,                        \
 291                  refcount_read(&_s->ref_count));                        \
 292         l2tp_session_inc_refcount_1(_s);                                \
 293 } while (0)
 294 #define l2tp_session_dec_refcount(_s)                                   \
 295 do {                                                                    \
 296         pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",       \
 297                  __func__, __LINE__, (_s)->name,                        \
 298                  refcount_read(&_s->ref_count));                        \
 299         l2tp_session_dec_refcount_1(_s);                                \
 300 } while (0)
 301 #else
 302 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
 303 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
 304 #endif
 305
 306 #define l2tp_printk(ptr, type, func, fmt, ...)                          \
 307 do {                                                                    \
 308         if (((ptr)->debug) & (type))                                    \
 309                 func(fmt, ##__VA_ARGS__);                               \
 310 } while (0)
 311
 312 #define l2tp_warn(ptr, type, fmt, ...)                                  \
 313         l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
 314 #define l2tp_info(ptr, type, fmt, ...)                                  \
 315         l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
 316 #define l2tp_dbg(ptr, type, fmt, ...)                                   \
 317         l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
 318
 319 #define MODULE_ALIAS_L2TP_PWTYPE(type) \
 320         MODULE_ALIAS("net-l2tp-type-" __stringify(type))
 321
 322 #endif /* _L2TP_CORE_H_ */