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
  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         struct u64_stats_sync   syncp;
  49 };
  50
  51 struct l2tp_tunnel;
  52
  53 /* Describes a session. Contains information to determine incoming
  54  * packets and transmit outgoing ones.
  55  */
  56 struct 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
  86 struct 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  */
 147 struct 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
 164 struct 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;
 192
 193         uint8_t                 priv[0];        /* private data */
 194 };
 195
 196 struct l2tp_nl_cmd_ops {
 197         int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
 198         int (*session_delete)(struct l2tp_session *session);
 199 };
 200
 201 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 202 {
 203         return &tunnel->priv[0];
 204 }
 205
 206 static inline void *l2tp_session_priv(struct l2tp_session *session)
 207 {
 208         return &session->priv[0];
 209 }
 210
 211 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 212 {
 213         struct l2tp_tunnel *tunnel;
 214
 215         if (sk == NULL)
 216                 return NULL;
 217
 218         sock_hold(sk);
 219         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 220         if (tunnel == NULL) {
 221                 sock_put(sk);
 222                 goto out;
 223         }
 224
 225         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 226
 227 out:
 228         return tunnel;
 229 }
 230
 231 extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
 232 extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
 233 extern struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
 234 extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 235 extern struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 236
 237 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);
 238 extern int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 239 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);
 240 extern int l2tp_session_delete(struct l2tp_session *session);
 241 extern void l2tp_session_free(struct l2tp_session *session);
 242 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));
 243 extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 244
 245 extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
 246
 247 extern int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
 248 extern void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 249
 250 /* Session reference counts. Incremented when code obtains a reference
 251  * to a session.
 252  */
 253 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 254 {
 255         atomic_inc(&session->ref_count);
 256 }
 257
 258 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
 259 {
 260         if (atomic_dec_and_test(&session->ref_count))
 261                 l2tp_session_free(session);
 262 }
 263
 264 #ifdef L2TP_REFCNT_DEBUG
 265 #define l2tp_session_inc_refcount(_s)                                   \
 266 do {                                                                    \
 267         pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",       \
 268                  __func__, __LINE__, (_s)->name,                        \
 269                  atomic_read(&_s->ref_count));                          \
 270         l2tp_session_inc_refcount_1(_s);                                \
 271 } while (0)
 272 #define l2tp_session_dec_refcount(_s)                                   \
 273 do {                                                                    \
 274         pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",       \
 275                  __func__, __LINE__, (_s)->name,                        \
 276                  atomic_read(&_s->ref_count));                          \
 277         l2tp_session_dec_refcount_1(_s);                                \
 278 } while (0)
 279 #else
 280 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
 281 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
 282 #endif
 283
 284 #define l2tp_printk(ptr, type, func, fmt, ...)                          \
 285 do {                                                                    \
 286         if (((ptr)->debug) & (type))                                    \
 287                 func(fmt, ##__VA_ARGS__);                               \
 288 } while (0)
 289
 290 #define l2tp_warn(ptr, type, fmt, ...)                                  \
 291         l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
 292 #define l2tp_info(ptr, type, fmt, ...)                                  \
 293         l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
 294 #define l2tp_dbg(ptr, type, fmt, ...)                                   \
 295         l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
 296
 297 #endif /* _L2TP_CORE_H_ */