/*
  *  OpenVPN -- An application to securely tunnel IP networks
  *             over a single TCP/UDP port, with support for SSL/TLS-based
  *             session authentication and key exchange,
  *             packet encryption, packet authentication, and
  *             packet compression.
  *

  *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>

  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2
  *  as published by the Free Software Foundation.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program (see the file COPYING included with this
  *  distribution); if not, write to the Free Software Foundation, Inc.,
  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
 #ifndef OPENVPN_H
 #define OPENVPN_H
 
 #include "buffer.h"
 #include "options.h"
 #include "socket.h"
 #include "crypto.h"
 #include "ssl.h"
 #include "packet_id.h"
 #include "lzo.h"
 #include "tun.h"
 #include "interval.h"
 #include "status.h"
 #include "fragment.h"
 #include "shaper.h"
 #include "route.h"
 #include "proxy.h"
 #include "socks.h"
 #include "sig.h"
 #include "misc.h"
 #include "mbuf.h"
 #include "pool.h"
 #include "plugin.h"
 #include "manage.h"

 #include "pf.h"

 
 /*
  * Our global key schedules, packaged thusly
  * to facilitate --persist-key.
  */
 
 struct key_schedule
 {

 #ifdef ENABLE_CRYPTO

   /* which cipher, HMAC digest, and key sizes are we using? */
   struct key_type key_type;
 
   /* pre-shared static key, read from a file */
   struct key_ctx_bi static_key;
 

 #ifdef ENABLE_SSL

   /* our global SSL context */

   struct tls_root_ctx ssl_ctx;

 
   /* optional authentication HMAC key for TLS control channel */
   struct key_ctx_bi tls_auth_key;
 

 #endif				/* ENABLE_SSL */
 #else				/* ENABLE_CRYPTO */

   int dummy;

 #endif				/* ENABLE_CRYPTO */

 };
 
 /*
  * struct packet_id_persist should be empty if we are not
  * building with crypto.
  */
 #ifndef PACKET_ID_H
 struct packet_id_persist
 {
   int dummy;
 };
 static inline void
 packet_id_persist_init (struct packet_id_persist *p)
 {
 }
 #endif
 
 /*
  * Packet processing buffers.
  */
 struct context_buffers
 {
   /* miscellaneous buffer, used by ping, occ, etc. */
   struct buffer aux_buf;
 
   /* workspace buffers used by crypto routines */

 #ifdef ENABLE_CRYPTO

   struct buffer encrypt_buf;
   struct buffer decrypt_buf;
 #endif
 
   /* workspace buffers for LZO compression */

 #ifdef ENABLE_LZO

   struct buffer lzo_compress_buf;
   struct buffer lzo_decompress_buf;
 #endif
 
   /*
    * Buffers used to read from TUN device
    * and TCP/UDP port.
    */
   struct buffer read_link_buf;
   struct buffer read_tun_buf;
 };
 

 /*
  * always-persistent context variables
  */
 struct context_persist
 {
   int restart_sleep_seconds;
 };
 

 
 /**************************************************************************/
 /**
  * Level 0 %context containing information related to the OpenVPN process.
  *
  * Level 0 state is initialized once at program startup, and then remains
  * throughout the lifetime of the OpenVPN process.  This structure
  * contains information related to the process's PID, user, and group.

  */
 struct context_0
 {
   /* workspace for get_pid_file/write_pid */
   struct pid_state pid_state;
 
   /* workspace for --user/--group */
   bool uid_gid_specified;
   bool uid_gid_set;
   struct user_state user_state;
   struct group_state group_state;
 };
 

 
 /**
  * Level 1 %context containing state that persists across \c SIGUSR1
  * restarts.
  *
  * Level 1 state is reset on \c SIGHUP restarts.  This structure is
  * initialized for every iteration of the \c main() function's outer \c
  * SIGHUP loop, but persists over iteration of that function's inner \c
  * SIGUSR1 loop.

  */
 struct context_1
 {
   struct link_socket_addr link_socket_addr;

                                 /**< Local and remote addresses on the
                                  *   external network. */

 
   /* tunnel session keys */
   struct key_schedule ks;
 
   /* persist crypto sequence number to/from file */
   struct packet_id_persist pid_persist;
 

   struct tuntap *tuntap;        /**< Tun/tap virtual network interface. */
   bool tuntap_owned;            /**< Whether the tun/tap interface should
                                  *   be cleaned up when this %context is
                                  *   cleaned up. */

 
   struct route_list *route_list;

                                 /**< List of routing information. See the
                                  *   \c --route command line option. */

   /* list of --route-ipv6 directives */
   struct route_ipv6_list *route_ipv6_list;
 

   /* --status file */
   struct status_output *status_output;
   bool status_output_owned;
 
 #ifdef ENABLE_HTTP_PROXY
   /* HTTP proxy object */
   struct http_proxy_info *http_proxy;

   bool http_proxy_owned;

 #endif
 
 #ifdef ENABLE_SOCKS
   /* SOCKS proxy object */
   struct socks_proxy_info *socks_proxy;

   bool socks_proxy_owned;

 #endif
 
 #if P2MP
 
 #if P2MP_SERVER
   /* persist --ifconfig-pool db to file */
   struct ifconfig_pool_persist *ifconfig_pool_persist;
   bool ifconfig_pool_persist_owned;
 #endif
 

   /* if client mode, hash of option strings we pulled from server */
   struct md5_digest pulled_options_digest_save;

                                 /**< Hash of option strings received from the
                                  *   remote OpenVPN server.  Only used in
                                  *   client-mode. */

 
   struct user_pass *auth_user_pass;

                                 /**< Username and password for
                                  *   authentication. */

 #endif
 };
 

 /**
  * Level 2 %context containing state that is reset on both \c SIGHUP and
  * \c SIGUSR1 restarts.
  *
  * This structure is initialized at the top of the \c
  * tunnel_point_to_point(), \c tunnel_server_udp_single_threaded(), and \c
  * tunnel_server_tcp() functions.  In other words, it is reset for every
  * iteration of the \c main() function's inner \c SIGUSR1 loop.

  */
 struct context_2
 {

   struct gc_arena gc;           /**< Garbage collection arena for
                                  *   allocations done in the level 2 scope
                                  *   of this context_2 structure. */

 
   /* our global wait events */
   struct event_set *event_set;
   int event_set_max;
   bool event_set_owned;
 
   /* event flags returned by io_wait */
 # define SOCKET_READ       (1<<0)
 # define SOCKET_WRITE      (1<<1)
 # define TUN_READ          (1<<2)
 # define TUN_WRITE         (1<<3)
 # define ES_ERROR          (1<<4)
 # define ES_TIMEOUT        (1<<5)
 # ifdef ENABLE_MANAGEMENT
 #  define MANAGEMENT_READ  (1<<6)
 #  define MANAGEMENT_WRITE (1<<7)
 # endif
 
   unsigned int event_set_status;
 
   struct link_socket *link_socket;	 /* socket used for TCP/UDP connection to remote */
   bool link_socket_owned;
   struct link_socket_info *link_socket_info;
   const struct link_socket *accept_from; /* possibly do accept() on a parent link_socket */
 

   struct link_socket_actual *to_link_addr;	/* IP address of remote */
   struct link_socket_actual from;               /* address of incoming datagram */

 
   /* MTU frame parameters */
   struct frame frame;
 
 #ifdef ENABLE_FRAGMENT
   /* Object to handle advanced MTU negotiation and datagram fragmentation */
   struct fragment_master *fragment;
   struct frame frame_fragment;
   struct frame frame_fragment_omit;
 #endif
 
 #ifdef HAVE_GETTIMEOFDAY
   /*
    * Traffic shaper object.
    */
   struct shaper shaper;
 #endif
 
   /*
    * Statistics
    */
   counter_type tun_read_bytes;
   counter_type tun_write_bytes;
   counter_type link_read_bytes;
   counter_type link_read_bytes_auth;
   counter_type link_write_bytes;

 #ifdef PACKET_TRUNCATION_CHECK
   counter_type n_trunc_tun_read;
   counter_type n_trunc_tun_write;
   counter_type n_trunc_pre_encrypt;
   counter_type n_trunc_post_decrypt;
 #endif

 
   /*
    * Timer objects for ping and inactivity
    * timeout features.
    */
   struct event_timeout wait_for_connect;
   struct event_timeout ping_send_interval;
   struct event_timeout ping_rec_interval;
 

   /* --inactive */
   struct event_timeout inactivity_interval;
   int inactivity_bytes;
 

 #ifdef ENABLE_OCC
   /* the option strings must match across peers */
   char *options_string_local;
   char *options_string_remote;
 
   int occ_op;			/* INIT to -1 */
   int occ_n_tries;
   struct event_timeout occ_interval;
 #endif
 
   /*
    * Keep track of maximum packet size received so far
    * (of authenticated packets).
    */
   int original_recv_size;	/* temporary */
   int max_recv_size_local;	/* max packet size received */
   int max_recv_size_remote;	/* max packet size received by remote */
   int max_send_size_local;	/* max packet size sent */
   int max_send_size_remote;	/* max packet size sent by remote */
 
 #ifdef ENABLE_OCC
   /* remote wants us to send back a load test packet of this size */
   int occ_mtu_load_size;
 
   struct event_timeout occ_mtu_load_test_interval;
   int occ_mtu_load_n_tries;
 #endif
 

 #ifdef ENABLE_CRYPTO

 
   /*
    * TLS-mode crypto objects.
    */

 #ifdef ENABLE_SSL

   struct tls_multi *tls_multi;  /**< TLS state structure for this VPN
                                  *   tunnel. */

 
   struct tls_auth_standalone *tls_auth_standalone;

                                 /**< TLS state structure required for the
                                  *   initial authentication of a client's
                                  *   connection attempt.  This structure
                                  *   is used by the \c
                                  *   tls_pre_decrypt_lite() function when
                                  *   it performs the HMAC firewall check
                                  *   on the first connection packet
                                  *   received from a new client.  See the
                                  *   \c --tls-auth commandline option. */

 
   /* used to optimize calls to tls_multi_process */
   struct interval tmp_int;
 
   /* throw this signal on TLS errors */
   int tls_exit_signal;
 

 #endif /* ENABLE_SSL */

 
   struct crypto_options crypto_options;

                                 /**< Security parameters and crypto state
                                  *   used by the \link data_crypto Data
                                  *   Channel Crypto module\endlink to
                                  *   process data channel packet. */

 
   /* used to keep track of data channel packet sequence numbers */
   struct packet_id packet_id;
   struct event_timeout packet_id_persist_interval;
 

 #endif /* ENABLE_CRYPTO */

 #ifdef ENABLE_LZO

   struct lzo_compress_workspace lzo_compwork;

                                 /**< Compression workspace used by the
                                  *   \link compression Data Channel
                                  *   Compression module\endlink. */

 #endif
 
   /*
    * Buffers used for packet processing.
    */
   struct context_buffers *buffers;
   bool buffers_owned; /* if true, we should free all buffers on close */
 
   /*
    * These buffers don't actually allocate storage, they are used
    * as pointers to the allocated buffers in
    * struct context_buffers.
    */
   struct buffer buf;
   struct buffer to_tun;
   struct buffer to_link;
 
   /*
    * IPv4 TUN device?
    */
   bool ipv4_tun;
 
   /* should we print R|W|r|w to console on packet transfers? */
   bool log_rw;
 
   /* route stuff */
   struct event_timeout route_wakeup;
   struct event_timeout route_wakeup_expire;
 
   /* did we open tun/tap dev during this cycle? */
   bool did_open_tun;
 
   /*
    * Event loop info
    */
 
   /* how long to wait on link/tun read before we will need to be serviced */
   struct timeval timeval;
 
   /* next wakeup for processing coarse timers (>1 sec resolution) */
   time_t coarse_timer_wakeup;
 
   /* maintain a random delta to add to timeouts to avoid contexts
      waking up simultaneously */
   time_t update_timeout_random_component;
   struct timeval timeout_random_component;
 
   /* indicates that the do_up_delay function has run */
   bool do_up_ran;
 
 #ifdef ENABLE_OCC
   /* indicates that we have received a SIGTERM when
      options->explicit_exit_notification is enabled,
      but we have not exited yet */
   time_t explicit_exit_notification_time_wait;
   struct event_timeout explicit_exit_notification_interval;
 #endif
 
   /* environmental variables to pass to scripts */
   struct env_set *es;

   bool es_owned;

 
   /* don't wait for TUN/TAP/UDP to be ready to accept write */
   bool fast_io;
 
 #if P2MP
 
 #if P2MP_SERVER
   /* --ifconfig endpoints to be pushed to client */
   bool push_reply_deferred;
   bool push_ifconfig_defined;

   bool sent_push_reply;

   in_addr_t push_ifconfig_local;
   in_addr_t push_ifconfig_remote_netmask;

 #ifdef ENABLE_CLIENT_NAT
   in_addr_t push_ifconfig_local_alias;
 #endif

   bool            push_ifconfig_ipv6_defined;
   struct in6_addr push_ifconfig_ipv6_local;
   int             push_ifconfig_ipv6_netbits;
   struct in6_addr push_ifconfig_ipv6_remote;
 

   /* client authentication state, CAS_SUCCEEDED must be 0 */
 # define CAS_SUCCEEDED 0
 # define CAS_PENDING   1
 # define CAS_FAILED    2
 # define CAS_PARTIAL   3 /* at least one client-connect script/plugin

 			    succeeded while a later one in the chain failed */
   int context_auth;
 #endif
 
   struct event_timeout push_request_interval;

   int n_sent_push_requests;

   bool did_pre_pull_restore;
 
   /* hash of pulled options, so we can compare when options change */
   struct md5_state pulled_options_state;
   struct md5_digest pulled_options_digest;

   struct event_timeout server_poll_interval;
 

   struct event_timeout scheduled_exit;

   int scheduled_exit_signal;

 #endif

   /* packet filter */
 #ifdef ENABLE_PF
   struct pf_context pf;

 #endif

 
 #ifdef MANAGEMENT_DEF_AUTH
   struct man_def_auth_context mda_context;
 #endif

 };
 

 
 /**

  * Contains all state information for one tunnel.

  *
  * This structure represents one VPN tunnel.  It is used to store state
  * information related to a VPN tunnel, but also includes process-wide
  * data, such as configuration options.
  *
  * The @ref tunnel_state "Structure of VPN tunnel state storage" related
  * page describes how this structure is used in client-mode and
  * server-mode.

  */
 struct context
 {

   struct options options;       /**< Options loaded from command line or
                                  *   configuration file. */

   bool first_time;              /**< True on the first iteration of
                                  *   OpenVPN's main loop. */

 
   /* context modes */
 # define CM_P2P            0 /* standalone point-to-point session or client */
 # define CM_TOP            1 /* top level of a multi-client or point-to-multipoint server */
 # define CM_TOP_CLONE      2 /* clone of a CM_TOP context for one thread */
 # define CM_CHILD_UDP      3 /* child context of a CM_TOP or CM_THREAD */
 # define CM_CHILD_TCP      4 /* child context of a CM_TOP or CM_THREAD */

   int mode;                     /**< Role of this context within the
                                  *   OpenVPN process.  Valid values are \c
                                  *   CM_P2P, \c CM_TOP, \c CM_TOP_CLONE,
                                  *   \c CM_CHILD_UDP, and \c CM_CHILD_TCP. */

   struct gc_arena gc;           /**< Garbage collection arena for
                                  *   allocations done in the scope of this
                                  *   context structure. */

   struct env_set *es;           /**< Set of environment variables. */

   struct signal_info *sig;      /**< Internal error signaling object. */

   struct plugin_list *plugins;  /**< List of plug-ins. */
   bool plugins_owned;           /**< Whether the plug-ins should be
                                  *   cleaned up when this %context is
                                  *   cleaned up. */

   bool did_we_daemonize;        /**< Whether demonization has already
                                  *   taken place. */

   struct context_persist persist;

                                 /**< Persistent %context. */
   struct context_0 *c0;         /**< Level 0 %context. */
   struct context_1 c1;          /**< Level 1 %context. */
   struct context_2 c2;          /**< Level 2 %context. */

 };
 
 /*
  * Check for a signal when inside an event loop
  */
 #define EVENT_LOOP_CHECK_SIGNAL(c, func, arg)   \
       if (IS_SIG (c))                           \
 	{                                       \
 	  const int brk = func (arg);           \
 	  perf_pop ();                          \
 	  if (brk)                              \
 	    break;                              \
 	  else                                  \
 	    continue;                           \
 	}
 
 /*
  * Macros for referencing objects which may not
  * have been compiled in.
  */
 

 #if defined(ENABLE_CRYPTO) && defined(ENABLE_SSL)

 #define TLS_MODE(c) ((c)->c2.tls_multi != NULL)
 #define PROTO_DUMP_FLAGS (check_debug_level (D_LINK_RW_VERBOSE) ? (PD_SHOW_DATA|PD_VERBOSE) : 0)
 #define PROTO_DUMP(buf, gc) protocol_dump((buf), \
 				      PROTO_DUMP_FLAGS | \
 				      (c->c2.tls_multi ? PD_TLS : 0) | \
 				      (c->options.tls_auth_file ? c->c1.ks.key_type.hmac_length : 0), \
 				      gc)
 #else
 #define TLS_MODE(c) (false)
 #define PROTO_DUMP(buf, gc) format_hex (BPTR (buf), BLEN (buf), 80, gc)
 #endif
 

 #ifdef ENABLE_CRYPTO

 #define MD5SUM(buf, len, gc) md5sum((buf), (len), 0, (gc))
 #else
 #define MD5SUM(buf, len, gc) "[unavailable]"
 #endif
 

 #ifdef ENABLE_CRYPTO

 #define CIPHER_ENABLED(c) (c->c1.ks.key_type.cipher != NULL)
 #else
 #define CIPHER_ENABLED(c) (false)
 #endif
 
 #endif