/*
  *  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) 2002-2009 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
  */
 
 #include "syshead.h"
 
 #include "socket.h"
 #include "fdmisc.h"
 #include "thread.h"
 #include "misc.h"
 #include "gremlin.h"
 #include "plugin.h"

 #include "ps.h"

 #include "manage.h"

 
 #include "memdbg.h"
 

 const int proto_overhead[] = { /* indexed by PROTO_x */
   IPv4_UDP_HEADER_SIZE,
   IPv4_TCP_HEADER_SIZE,
   IPv4_TCP_HEADER_SIZE,
   IPv4_TCP_HEADER_SIZE
 };
 

 /*
  * Functions related to the translation of DNS names to IP addresses.
  */
 
 static const char*
 h_errno_msg(int h_errno_err)
 {
   switch (h_errno_err)
     {
     case HOST_NOT_FOUND:
       return "[HOST_NOT_FOUND] The specified host is unknown.";
     case NO_DATA:
       return "[NO_DATA] The requested name is valid but does not have an IP address.";
     case NO_RECOVERY:
       return "[NO_RECOVERY] A non-recoverable name server error occurred.";
     case TRY_AGAIN:
       return "[TRY_AGAIN] A temporary error occurred on an authoritative name server.";
     }
   return "[unknown h_errno value]";
 }
 
 /*
  * Translate IP addr or hostname to in_addr_t.
  * If resolve error, try again for
  * resolve_retry_seconds seconds.
  */
 in_addr_t
 getaddr (unsigned int flags,
 	 const char *hostname,
 	 int resolve_retry_seconds,
 	 bool *succeeded,
 	 volatile int *signal_received)
 {
   struct in_addr ia;
   int status;
   int sigrec = 0;
   int msglevel = (flags & GETADDR_FATAL) ? M_FATAL : D_RESOLVE_ERRORS;
 
   if (flags & GETADDR_MSG_VIRT_OUT)
     msglevel |= M_MSG_VIRT_OUT;
 
   CLEAR (ia);
   if (succeeded)
     *succeeded = false;
 
   if ((flags & (GETADDR_FATAL_ON_SIGNAL|GETADDR_WARN_ON_SIGNAL))
       && !signal_received)
     signal_received = &sigrec;
 
   status = openvpn_inet_aton (hostname, &ia); /* parse ascii IP address */
 
   if (status != OIA_IP) /* parse as IP address failed? */
     {
       const int fail_wait_interval = 5; /* seconds */
       int resolve_retries = (flags & GETADDR_TRY_ONCE) ? 1 : (resolve_retry_seconds / fail_wait_interval);
       struct hostent *h;
       const char *fmt;
       int level = 0;
 
       CLEAR (ia);
 
       fmt = "RESOLVE: Cannot resolve host address: %s: %s";
       if ((flags & GETADDR_MENTION_RESOLVE_RETRY)
 	  && !resolve_retry_seconds)
 	fmt = "RESOLVE: Cannot resolve host address: %s: %s (I would have retried this name query if you had specified the --resolv-retry option.)";
 
       if (!(flags & GETADDR_RESOLVE) || status == OIA_ERROR)
 	{
 	  msg (msglevel, "RESOLVE: Cannot parse IP address: %s", hostname);
 	  goto done;
 	}
 

 #ifdef ENABLE_MANAGEMENT
       if (flags & GETADDR_UPDATE_MANAGEMENT_STATE)
 	{
 	  if (management)
 	    management_set_state (management,
 				  OPENVPN_STATE_RESOLVE,
 				  NULL,
 				  (in_addr_t)0,
 				  (in_addr_t)0);
 	}
 #endif
 

       /*
        * Resolve hostname
        */
       while (true)
 	{
 	  /* try hostname lookup */

 #if defined(HAVE_RES_INIT)
 	  res_init ();
 #endif

 	  h = gethostbyname (hostname);
 
 	  if (signal_received)
 	    {
 	      get_signal (signal_received);
 	      if (*signal_received) /* were we interrupted by a signal? */
 		{
 		  h = NULL;
 		  if (*signal_received == SIGUSR1) /* ignore SIGUSR1 */
 		    {
 		      msg (level, "RESOLVE: Ignored SIGUSR1 signal received during DNS resolution attempt");
 		      *signal_received = 0;
 		    }
 		  else
 		    goto done;
 		}
 	    }
 
 	  /* success? */
 	  if (h)
 	    break;
 
 	  /* resolve lookup failed, should we
 	     continue or fail? */
 
 	  level = msglevel;
 	  if (resolve_retries > 0)
 	    level = D_RESOLVE_ERRORS;
 
 	  msg (level,
 	       fmt,
 	       hostname,
 	       h_errno_msg (h_errno));
 
 	  if (--resolve_retries <= 0)
 	    goto done;
 
 	  openvpn_sleep (fail_wait_interval);
 	}
 
       if (h->h_addrtype != AF_INET || h->h_length != 4)
 	{
 	    msg (msglevel, "RESOLVE: Sorry, but we only accept IPv4 DNS names: %s", hostname);
 	    goto done;
 	}
 
       ia.s_addr = *(in_addr_t *) (h->h_addr_list[0]);
 
       if (ia.s_addr)
 	{
 	  if (h->h_addr_list[1]) /* more than one address returned */
 	    {
 	      int n = 0;
 
 	      /* count address list */
 	      while (h->h_addr_list[n])
 		++n;
 	      ASSERT (n >= 2);
 
 	      msg (D_RESOLVE_ERRORS, "RESOLVE: NOTE: %s resolves to %d addresses, choosing one by random",
 		   hostname,
 		   n);
 
 	      /* choose address randomly, for basic load-balancing capability */
 	      ia.s_addr = *(in_addr_t *) (h->h_addr_list[get_random () % n]);
 	    }
 	}
 
       /* hostname resolve succeeded */
       if (succeeded)
 	*succeeded = true;
     }
   else
     {
       /* IP address parse succeeded */
       if (succeeded)
 	*succeeded = true;
     }
 
  done:
   if (signal_received && *signal_received)
     {
       int level = 0;
       if (flags & GETADDR_FATAL_ON_SIGNAL)
 	level = M_FATAL;
       else if (flags & GETADDR_WARN_ON_SIGNAL)
 	level = M_WARN;
       msg (level, "RESOLVE: signal received during DNS resolution attempt");
     }
 
   return (flags & GETADDR_HOST_ORDER) ? ntohl (ia.s_addr) : ia.s_addr;
 }
 
 /*
  * We do our own inet_aton because the glibc function
  * isn't very good about error checking.
  */
 int
 openvpn_inet_aton (const char *dotted_quad, struct in_addr *addr)
 {
   unsigned int a, b, c, d;
 
   CLEAR (*addr);
   if (sscanf (dotted_quad, "%u.%u.%u.%u", &a, &b, &c, &d) == 4)
     {
       if (a < 256 && b < 256 && c < 256 && d < 256)
 	{
 	  addr->s_addr = htonl (a<<24 | b<<16 | c<<8 | d);
 	  return OIA_IP; /* good dotted quad */
 	}
     }
   if (string_class (dotted_quad, CC_DIGIT|CC_DOT, 0))
     return OIA_ERROR;    /* probably a badly formatted dotted quad */
   else
     return OIA_HOSTNAME; /* probably a hostname */
 }
 

 bool
 ip_addr_dotted_quad_safe (const char *dotted_quad)
 {
   /* verify non-NULL */
   if (!dotted_quad)
     return false;
 
   /* verify length is within limits */
   if (strlen (dotted_quad) > 15)
     return false;
 
   /* verify that all chars are either numeric or '.' and that no numeric
      substring is greater than 3 chars */
   {
     int nnum = 0;
     const char *p = dotted_quad;
     int c;
 
     while ((c = *p++))
       {
 	if (c >= '0' && c <= '9')
 	  {
 	    ++nnum;
 	    if (nnum > 3)
 	      return false;
 	  }
 	else if (c == '.')
 	  {
 	    nnum = 0;
 	  }
 	else
 	  return false;
       }
   }
 
   /* verify that string will convert to IP address */
   {
     struct in_addr a;
     return openvpn_inet_aton (dotted_quad, &a) == OIA_IP;
   }
 }
 

 static bool
 dns_addr_safe (const char *addr)
 {
   if (addr)
     {
       const size_t len = strlen (addr);
       return len > 0 && len <= 255 && string_class (addr, CC_ALNUM|CC_DASH|CC_DOT, 0);
     }
   else
     return false;
 }
 

 bool

 ip_or_dns_addr_safe (const char *addr, const bool allow_fqdn)

 {

   if (ip_addr_dotted_quad_safe (addr))

     return true;
   else if (allow_fqdn)

     return dns_addr_safe (addr);

   else
     return false;
 }
 

 bool
 mac_addr_safe (const char *mac_addr)
 {
   /* verify non-NULL */
   if (!mac_addr)
     return false;
 
   /* verify length is within limits */
   if (strlen (mac_addr) > 17)
     return false;
 
   /* verify that all chars are either alphanumeric or ':' and that no
      alphanumeric substring is greater than 2 chars */
   {
     int nnum = 0;
     const char *p = mac_addr;
     int c;
 
     while ((c = *p++))
       {
 	if ( (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F') )
 	  {
 	    ++nnum;
 	    if (nnum > 2)
 	      return false;
 	  }
 	else if (c == ':')
 	  {
 	    nnum = 0;
 	  }
 	else
 	  return false;
       }
   }
 
   /* error-checking is left to script invoked in lladdr.c */
   return true;
 }
 

 static void
 update_remote (const char* host,

 	       struct openvpn_sockaddr *addr,

 	       bool *changed)
 {
   if (host && addr)
     {
       const in_addr_t new_addr = getaddr (

 					  GETADDR_RESOLVE|GETADDR_UPDATE_MANAGEMENT_STATE,

 					  host,
 					  1,
 					  NULL,
 					  NULL);

       if (new_addr && addr->sa.sin_addr.s_addr != new_addr)

 	{

 	  addr->sa.sin_addr.s_addr = new_addr;

 	  *changed = true;
 	}
     }
 }
 
 static int
 socket_get_sndbuf (int sd)
 {
 #if defined(HAVE_GETSOCKOPT) && defined(SOL_SOCKET) && defined(SO_SNDBUF)
   int val;
   socklen_t len;
 
   len = sizeof (val);
   if (getsockopt (sd, SOL_SOCKET, SO_SNDBUF, (void *) &val, &len) == 0
       && len == sizeof (val))
     return val;
 #endif
   return 0;
 }
 
 static void
 socket_set_sndbuf (int sd, int size)
 {
 #if defined(HAVE_SETSOCKOPT) && defined(SOL_SOCKET) && defined(SO_SNDBUF)

   if (size > 0 && size < SOCKET_SND_RCV_BUF_MAX)

     {

       if (setsockopt (sd, SOL_SOCKET, SO_SNDBUF, (void *) &size, sizeof (size)) != 0)
 	{
 	  msg (M_WARN, "NOTE: setsockopt SO_SNDBUF=%d failed", size);
 	}

     }
 #endif
 }
 
 static int
 socket_get_rcvbuf (int sd)
 {
 #if defined(HAVE_GETSOCKOPT) && defined(SOL_SOCKET) && defined(SO_RCVBUF)
   int val;
   socklen_t len;
 
   len = sizeof (val);
   if (getsockopt (sd, SOL_SOCKET, SO_RCVBUF, (void *) &val, &len) == 0
       && len == sizeof (val))
     return val;
 #endif
   return 0;
 }
 
 static bool
 socket_set_rcvbuf (int sd, int size)
 {
 #if defined(HAVE_SETSOCKOPT) && defined(SOL_SOCKET) && defined(SO_RCVBUF)

   if (size > 0 && size < SOCKET_SND_RCV_BUF_MAX)

     {

       if (setsockopt (sd, SOL_SOCKET, SO_RCVBUF, (void *) &size, sizeof (size)) != 0)
 	{
 	  msg (M_WARN, "NOTE: setsockopt SO_RCVBUF=%d failed", size);
 	  return false;
 	}

     }
   return true;
 #endif
 }
 
 static void
 socket_set_buffers (int fd, const struct socket_buffer_size *sbs)
 {
   if (sbs)
     {
       const int sndbuf_old = socket_get_sndbuf (fd);
       const int rcvbuf_old = socket_get_rcvbuf (fd);
 
       if (sbs->sndbuf)
 	socket_set_sndbuf (fd, sbs->sndbuf);
 
       if (sbs->rcvbuf)
 	socket_set_rcvbuf (fd, sbs->rcvbuf);
        
       msg (D_OSBUF, "Socket Buffers: R=[%d->%d] S=[%d->%d]",
 	   rcvbuf_old,
 	   socket_get_rcvbuf (fd),
 	   sndbuf_old,
 	   socket_get_sndbuf (fd));
     }
 }
 
 /*

  * Set other socket options
  */
 
 static bool
 socket_set_tcp_nodelay (int sd, int state)
 {
 #if defined(HAVE_SETSOCKOPT) && defined(IPPROTO_TCP) && defined(TCP_NODELAY)
   if (setsockopt (sd, IPPROTO_TCP, TCP_NODELAY, (void *) &state, sizeof (state)) != 0)
     {
       msg (M_WARN, "NOTE: setsockopt TCP_NODELAY=%d failed", state);
       return false;
     }
   else
     {
       dmsg (D_OSBUF, "Socket flags: TCP_NODELAY=%d succeeded", state);
       return true;
     }
 #else
   msg (M_WARN, "NOTE: setsockopt TCP_NODELAY=%d failed (No kernel support)", state);
   return false;
 #endif
 }
 
 static bool
 socket_set_flags (int sd, unsigned int sockflags)
 {
   if (sockflags & SF_TCP_NODELAY)
     return socket_set_tcp_nodelay (sd, 1);
   else
     return true;
 }
 
 bool
 link_socket_update_flags (struct link_socket *ls, unsigned int sockflags)
 {
   if (ls && socket_defined (ls->sd))
     return socket_set_flags (ls->sd, ls->sockflags = sockflags);
   else
     return false;
 }
 
 void
 link_socket_update_buffer_sizes (struct link_socket *ls, int rcvbuf, int sndbuf)
 {
   if (ls && socket_defined (ls->sd))
     {
       ls->socket_buffer_sizes.sndbuf = sndbuf;
       ls->socket_buffer_sizes.rcvbuf = rcvbuf;
       socket_set_buffers (ls->sd, &ls->socket_buffer_sizes);
     }
 }
 
 /*

  * SOCKET INITALIZATION CODE.
  * Create a TCP/UDP socket
  */
 
 socket_descriptor_t
 create_socket_tcp (void)
 {
   socket_descriptor_t sd;
 
   if ((sd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
     msg (M_SOCKERR, "Cannot create TCP socket");
 

 #ifndef WIN32 /* using SO_REUSEADDR on Windows will cause bind to succeed on port conflicts! */

   /* set SO_REUSEADDR on socket */
   {
     int on = 1;
     if (setsockopt (sd, SOL_SOCKET, SO_REUSEADDR,
 		    (void *) &on, sizeof (on)) < 0)
       msg (M_SOCKERR, "TCP: Cannot setsockopt SO_REUSEADDR on TCP socket");
   }

 #endif

 
 #if 0
   /* set socket linger options */
   {
     struct linger linger;
     linger.l_onoff = 1;
     linger.l_linger = 2;
     if (setsockopt (sd, SOL_SOCKET, SO_LINGER,
 		    (void *) &linger, sizeof (linger)) < 0)
       msg (M_SOCKERR, "TCP: Cannot setsockopt SO_LINGER on TCP socket");
   }
 #endif
 
   return sd;
 }
 
 static socket_descriptor_t

 create_socket_udp (const unsigned int flags)

 {
   socket_descriptor_t sd;
 
   if ((sd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
     msg (M_SOCKERR, "UDP: Cannot create UDP socket");

 #if ENABLE_IP_PKTINFO
   else if (flags & SF_USE_IP_PKTINFO)
     {
       int pad = 1;
       setsockopt (sd, SOL_IP, IP_PKTINFO, (void*)&pad, sizeof(pad));
     }
 #endif

   return sd;
 }
 
 static void
 create_socket (struct link_socket *sock)
 {
   /* create socket */
   if (sock->info.proto == PROTO_UDPv4)
     {

       sock->sd = create_socket_udp (sock->sockflags);

 
 #ifdef ENABLE_SOCKS
       if (sock->socks_proxy)
 	sock->ctrl_sd = create_socket_tcp ();
 #endif
     }
   else if (sock->info.proto == PROTO_TCPv4_SERVER
 	   || sock->info.proto == PROTO_TCPv4_CLIENT)
     {
       sock->sd = create_socket_tcp ();
     }
   else
     {
       ASSERT (0);
     }
 }
 
 /*
  * Functions used for establishing a TCP stream connection.
  */
 
 static void
 socket_do_listen (socket_descriptor_t sd,

 		  const struct openvpn_sockaddr *local,

 		  bool do_listen,
 		  bool do_set_nonblock)
 {
   struct gc_arena gc = gc_new ();
   if (do_listen)
     {
       msg (M_INFO, "Listening for incoming TCP connection on %s", 
 	   print_sockaddr (local, &gc));
       if (listen (sd, 1))
 	msg (M_SOCKERR, "TCP: listen() failed");
     }
 
   /* set socket to non-blocking mode */
   if (do_set_nonblock)
     set_nonblock (sd);
 
   gc_free (&gc);
 }
 
 socket_descriptor_t
 socket_do_accept (socket_descriptor_t sd,

 		  struct link_socket_actual *act,

 		  const bool nowait)
 {

   socklen_t remote_len = sizeof (act->dest.sa);

   socket_descriptor_t new_sd = SOCKET_UNDEFINED;
 

   CLEAR (*act);
 

 #ifdef HAVE_GETPEERNAME
   if (nowait)
     {

       new_sd = getpeername (sd, (struct sockaddr *) &act->dest.sa, &remote_len);

 
       if (!socket_defined (new_sd))
 	msg (D_LINK_ERRORS | M_ERRNO_SOCK, "TCP: getpeername() failed");
       else
 	new_sd = sd;
     }
 #else
   if (nowait)
     msg (M_WARN, "TCP: this OS does not provide the getpeername() function");
 #endif
   else
     {

       new_sd = accept (sd, (struct sockaddr *) &act->dest.sa, &remote_len);

     }
 

 #if 0 /* For debugging only, test the effect of accept() failures */
  {
    static int foo = 0;
    ++foo;
    if (foo & 1)
      new_sd = -1;
  }
 #endif
 

   if (!socket_defined (new_sd))
     {
       msg (D_LINK_ERRORS | M_ERRNO_SOCK, "TCP: accept(%d) failed", sd);
     }

   else if (remote_len != sizeof (act->dest.sa))

     {
       msg (D_LINK_ERRORS, "TCP: Received strange incoming connection with unknown address length=%d", remote_len);
       openvpn_close_socket (new_sd);
       new_sd = SOCKET_UNDEFINED;
     }
   return new_sd;
 }
 
 static void

 tcp_connection_established (const struct link_socket_actual *act)

 {
   struct gc_arena gc = gc_new ();
   msg (M_INFO, "TCP connection established with %s", 

        print_link_socket_actual (act, &gc));

   gc_free (&gc);
 }
 
 static int
 socket_listen_accept (socket_descriptor_t sd,

 		      struct link_socket_actual *act,

 		      const char *remote_dynamic,
 		      bool *remote_changed,

 		      const struct openvpn_sockaddr *local,

 		      bool do_listen,
 		      bool nowait,
 		      volatile int *signal_received)
 {
   struct gc_arena gc = gc_new ();

   /* struct openvpn_sockaddr *remote = &act->dest; */

   struct openvpn_sockaddr remote_verify = act->dest;

   int new_sd = SOCKET_UNDEFINED;
 

   CLEAR (*act);

   socket_do_listen (sd, local, do_listen, true);
 
   while (true)
     {
       int status;
       fd_set reads;
       struct timeval tv;
 
       FD_ZERO (&reads);
       FD_SET (sd, &reads);
       tv.tv_sec = 0;
       tv.tv_usec = 0;
 
       status = select (sd + 1, &reads, NULL, NULL, &tv);
 
       get_signal (signal_received);
       if (*signal_received)
 	{
 	  gc_free (&gc);
 	  return sd;
 	}
 
       if (status < 0)
 	msg (D_LINK_ERRORS | M_ERRNO_SOCK, "TCP: select() failed");
 
       if (status <= 0)
 	{
 	  openvpn_sleep (1);
 	  continue;
 	}
 

       new_sd = socket_do_accept (sd, act, nowait);

 
       if (socket_defined (new_sd))
 	{
 	  update_remote (remote_dynamic, &remote_verify, remote_changed);
 	  if (addr_defined (&remote_verify)

 	      && !addr_match (&remote_verify, &act->dest))

 	    {
 	      msg (M_WARN,
 		   "TCP NOTE: Rejected connection attempt from %s due to --remote setting",

 		   print_link_socket_actual (act, &gc));

 	      if (openvpn_close_socket (new_sd))
 		msg (M_SOCKERR, "TCP: close socket failed (new_sd)");
 	    }
 	  else
 	    break;
 	}
       openvpn_sleep (1);
     }
 
   if (!nowait && openvpn_close_socket (sd))
     msg (M_SOCKERR, "TCP: close socket failed (sd)");
 

   tcp_connection_established (act);

 
   gc_free (&gc);
   return new_sd;
 }
 

 void

 socket_bind (socket_descriptor_t sd,

              struct openvpn_sockaddr *local,
 	     const char *prefix)

 {
   struct gc_arena gc = gc_new ();
 
   if (bind (sd, (struct sockaddr *) &local->sa, sizeof (local->sa)))
     {
       const int errnum = openvpn_errno_socket ();

       msg (M_FATAL, "%s: Socket bind failed on local address %s: %s",
 	   prefix,

            print_sockaddr (local, &gc),
            strerror_ts (errnum, &gc));
     }
   gc_free (&gc);
 }
 

 int

 openvpn_connect (socket_descriptor_t sd,
 		 struct openvpn_sockaddr *remote,
 		 int connect_timeout,
 		 volatile int *signal_received)
 {
   int status = 0;
 
 #ifdef CONNECT_NONBLOCK
   set_nonblock (sd);
   status = connect (sd, (struct sockaddr *) &remote->sa, sizeof (remote->sa));
   if (status)
     status = openvpn_errno_socket ();
   if (status == EINPROGRESS)
     {
       while (true)
 	{
 	  fd_set writes;
 	  struct timeval tv;
 
 	  FD_ZERO (&writes);
 	  FD_SET (sd, &writes);
 	  tv.tv_sec = 0;
 	  tv.tv_usec = 0;
 
 	  status = select (sd + 1, NULL, &writes, NULL, &tv);
 

 	  if (signal_received)

 	    {

 	      get_signal (signal_received);
 	      if (*signal_received)
 		{
 		  status = 0;
 		  break;
 		}

 	    }
 	  if (status < 0)
 	    {
 	      status = openvpn_errno_socket ();
 	      break;
 	    }
 	  if (status <= 0)
 	    {
 	      if (--connect_timeout < 0)
 		{
 		  status = ETIMEDOUT;
 		  break;
 		}
 	      openvpn_sleep (1);
 	      continue;
 	    }
 
 	  /* got it */
 	  {
 	    int val = 0;
 	    socklen_t len;
 
 	    len = sizeof (val);
 	    if (getsockopt (sd, SOL_SOCKET, SO_ERROR, (void *) &val, &len) == 0
 		&& len == sizeof (val))
 	      status = val;
 	    else
 	      status = openvpn_errno_socket ();
 	    break;
 	  }
 	}
     }
 #else
   status = connect (sd, (struct sockaddr *) &remote->sa, sizeof (remote->sa));
   if (status)
     status = openvpn_errno_socket ();
 #endif
 
   return status;
 }
 

 void

 socket_connect (socket_descriptor_t *sd,

                 struct openvpn_sockaddr *local,
                 bool bind_local,

 		struct openvpn_sockaddr *remote,

 		const bool connection_profiles_defined,

 		const char *remote_dynamic,
 		bool *remote_changed,
 		const int connect_retry_seconds,

 		const int connect_timeout,

 		const int connect_retry_max,

 		volatile int *signal_received)
 {
   struct gc_arena gc = gc_new ();

   int retry = 0;

 #ifdef CONNECT_NONBLOCK
   msg (M_INFO, "Attempting to establish TCP connection with %s [nonblock]", 
        print_sockaddr (remote, &gc));
 #else

   msg (M_INFO, "Attempting to establish TCP connection with %s", 
        print_sockaddr (remote, &gc));

 #endif
 

   while (true)
     {

       int status;

 #ifdef ENABLE_MANAGEMENT
       if (management)
 	management_set_state (management,
 			      OPENVPN_STATE_TCP_CONNECT,
 			      NULL,
 			      (in_addr_t)0,
 			      (in_addr_t)0);
 #endif
 

       status = openvpn_connect (*sd, remote, connect_timeout, signal_received);

       get_signal (signal_received);
       if (*signal_received)
 	goto done;
 
       if (!status)
 	break;
 

       msg (D_LINK_ERRORS,
 	   "TCP: connect to %s failed, will try again in %d seconds: %s",

 	   print_sockaddr (remote, &gc),

 	   connect_retry_seconds,
 	   strerror_ts (status, &gc));

       gc_reset (&gc);
 

       openvpn_close_socket (*sd);

       *sd = SOCKET_UNDEFINED;
 

       if ((connect_retry_max > 0 && ++retry >= connect_retry_max) || connection_profiles_defined)

 	{
 	  *signal_received = SIGUSR1;
 	  goto done;
 	}
 

       openvpn_sleep (connect_retry_seconds);
 

       get_signal (signal_received);
       if (*signal_received)
 	goto done;
 

       *sd = create_socket_tcp ();

       if (bind_local)

         socket_bind (*sd, local, "TCP Client");

       update_remote (remote_dynamic, remote, remote_changed);
     }
 
   msg (M_INFO, "TCP connection established with %s", 
        print_sockaddr (remote, &gc));
 
  done:
   gc_free (&gc);
 }
 
 /* For stream protocols, allocate a buffer to build up packet.
    Called after frame has been finalized. */
 
 static void
 socket_frame_init (const struct frame *frame, struct link_socket *sock)
 {
 #ifdef WIN32
   overlapped_io_init (&sock->reads, frame, FALSE, false);
   overlapped_io_init (&sock->writes, frame, TRUE, false);
   sock->rw_handle.read = sock->reads.overlapped.hEvent;
   sock->rw_handle.write = sock->writes.overlapped.hEvent;
 #endif
 
   if (link_socket_connection_oriented (sock))
     {
 #ifdef WIN32

       stream_buf_init (&sock->stream_buf,
 		       &sock->reads.buf_init,
 		       sock->sockflags,
 		       sock->info.proto);

 #else
       alloc_buf_sock_tun (&sock->stream_buf_data,
 			  frame,
 			  false,
 			  FRAME_HEADROOM_MARKER_READ_STREAM);

 
       stream_buf_init (&sock->stream_buf,
 		       &sock->stream_buf_data,
 		       sock->sockflags,
 		       sock->info.proto);

 #endif
     }
 }
 
 /*
  * Adjust frame structure based on a Path MTU value given
  * to us by the OS.
  */
 void
 frame_adjust_path_mtu (struct frame *frame, int pmtu, int proto)
 {
   frame_set_mtu_dynamic (frame, pmtu - datagram_overhead (proto), SET_MTU_UPPER_BOUND);
 }
 
 static void
 resolve_bind_local (struct link_socket *sock)
 {
   struct gc_arena gc = gc_new ();
 
   /* resolve local address if undefined */
   if (!addr_defined (&sock->info.lsa->local))
     {

       sock->info.lsa->local.sa.sin_family = AF_INET;
       sock->info.lsa->local.sa.sin_addr.s_addr =

 	(sock->local_host ? getaddr (GETADDR_RESOLVE | GETADDR_WARN_ON_SIGNAL | GETADDR_FATAL,
 				     sock->local_host,
 				     0,
 				     NULL,
 				     NULL)
 	 : htonl (INADDR_ANY));

       sock->info.lsa->local.sa.sin_port = htons (sock->local_port);

     }
   
   /* bind to local address/port */
   if (sock->bind_local)
     {

 #ifdef ENABLE_SOCKS
       if (sock->socks_proxy && sock->info.proto == PROTO_UDPv4)

           socket_bind (sock->ctrl_sd, &sock->info.lsa->local, "SOCKS");

       else
 #endif

           socket_bind (sock->sd, &sock->info.lsa->local, "TCP/UDP");

     }
   gc_free (&gc);
 }
 
 static void
 resolve_remote (struct link_socket *sock,
 		int phase,
 		const char **remote_dynamic,
 		volatile int *signal_received)
 {
   struct gc_arena gc = gc_new ();
 
   if (!sock->did_resolve_remote)
     {
       /* resolve remote address if undefined */
       if (!addr_defined (&sock->info.lsa->remote))
 	{

 	  sock->info.lsa->remote.sa.sin_family = AF_INET;
 	  sock->info.lsa->remote.sa.sin_addr.s_addr = 0;

 
 	  if (sock->remote_host)
 	    {

 	      unsigned int flags = GETADDR_RESOLVE|GETADDR_UPDATE_MANAGEMENT_STATE;

 	      int retry = 0;
 	      bool status = false;
 

 	      if (sock->connection_profiles_defined && sock->resolve_retry_seconds == RESOLV_RETRY_INFINITE)

 		{
 		  if (phase == 2)
 		    flags |= (GETADDR_TRY_ONCE | GETADDR_FATAL);
 		  retry = 0;
 		}
 	      else if (phase == 1)
 		{
 		  if (sock->resolve_retry_seconds)
 		    {
 		      retry = 0;
 		    }
 		  else
 		    {

 		      flags |= (GETADDR_FATAL | GETADDR_MENTION_RESOLVE_RETRY);

 		      retry = 0;
 		    }
 		}
 	      else if (phase == 2)
 		{
 		  if (sock->resolve_retry_seconds)
 		    {

 		      flags |= GETADDR_FATAL;

 		      retry = sock->resolve_retry_seconds;
 		    }
 		  else
 		    {
 		      ASSERT (0);
 		    }
 		}
 	      else
 		{
 		  ASSERT (0);
 		}
 

 	      sock->info.lsa->remote.sa.sin_addr.s_addr = getaddr (

 		    flags,
 		    sock->remote_host,
 		    retry,
 		    &status,
 		    signal_received);
 	      
 	      dmsg (D_SOCKET_DEBUG, "RESOLVE_REMOTE flags=0x%04x phase=%d rrs=%d sig=%d status=%d",
 		   flags,
 		   phase,
 		   retry,
 		   signal_received ? *signal_received : -1,
 		   status);
 
 	      if (signal_received)
 		{
 		  if (*signal_received)
 		    goto done;
 		}
 	      if (!status)
 		{
 		  if (signal_received)
 		    *signal_received = SIGUSR1;
 		  goto done;
 		}
 	    }
 

 	  sock->info.lsa->remote.sa.sin_port = htons (sock->remote_port);

 	}
   
       /* should we re-use previous active remote address? */

       if (link_socket_actual_defined (&sock->info.lsa->actual))

 	{
 	  msg (M_INFO, "TCP/UDP: Preserving recently used remote address: %s",

 	       print_link_socket_actual (&sock->info.lsa->actual, &gc));

 	  if (remote_dynamic)
 	    *remote_dynamic = NULL;
 	}
       else

 	{
 	  CLEAR (sock->info.lsa->actual);
 	  sock->info.lsa->actual.dest = sock->info.lsa->remote;
 	}

 
       /* remember that we finished */
       sock->did_resolve_remote = true;
     }
 
  done:
   gc_free (&gc);
 }
 
 struct link_socket *
 link_socket_new (void)
 {
   struct link_socket *sock;
 
   ALLOC_OBJ_CLEAR (sock, struct link_socket);
   sock->sd = SOCKET_UNDEFINED;
 #ifdef ENABLE_SOCKS
   sock->ctrl_sd = SOCKET_UNDEFINED;
 #endif
   return sock;
 }
 
 /* bind socket if necessary */
 void
 link_socket_init_phase1 (struct link_socket *sock,

 			 const bool connection_profiles_defined,

 			 const char *local_host,
 			 int local_port,

 			 const char *remote_host,
 			 int remote_port,

 			 int proto,
 			 int mode,
 			 const struct link_socket *accept_from,
 #ifdef ENABLE_HTTP_PROXY
 			 struct http_proxy_info *http_proxy,
 #endif
 #ifdef ENABLE_SOCKS
 			 struct socks_proxy_info *socks_proxy,
 #endif
 #ifdef ENABLE_DEBUG
 			 int gremlin,
 #endif
 			 bool bind_local,
 			 bool remote_float,
 			 int inetd,
 			 struct link_socket_addr *lsa,
 			 const char *ipchange_command,
 			 const struct plugin_list *plugins,
 			 int resolve_retry_seconds,
 			 int connect_retry_seconds,

 			 int connect_timeout,

 			 int connect_retry_max,

 			 int mtu_discover_type,
 			 int rcvbuf,

 			 int sndbuf,
 			 unsigned int sockflags)

 {
   ASSERT (sock);
 

   sock->connection_profiles_defined = connection_profiles_defined;

 
   sock->local_host = local_host;
   sock->local_port = local_port;

   sock->remote_host = remote_host;
   sock->remote_port = remote_port;

 
 #ifdef ENABLE_HTTP_PROXY
   sock->http_proxy = http_proxy;
 #endif
 
 #ifdef ENABLE_SOCKS
   sock->socks_proxy = socks_proxy;
 #endif
 
   sock->bind_local = bind_local;
   sock->inetd = inetd;
   sock->resolve_retry_seconds = resolve_retry_seconds;
   sock->connect_retry_seconds = connect_retry_seconds;

   sock->connect_timeout = connect_timeout;

   sock->connect_retry_max = connect_retry_max;

   sock->mtu_discover_type = mtu_discover_type;
 
 #ifdef ENABLE_DEBUG
   sock->gremlin = gremlin;
 #endif
 
   sock->socket_buffer_sizes.rcvbuf = rcvbuf;
   sock->socket_buffer_sizes.sndbuf = sndbuf;
 

   sock->sockflags = sockflags;
 

   sock->info.proto = proto;
   sock->info.remote_float = remote_float;
   sock->info.lsa = lsa;
   sock->info.ipchange_command = ipchange_command;
   sock->info.plugins = plugins;
 
   sock->mode = mode;
   if (mode == LS_MODE_TCP_ACCEPT_FROM)
     {
       ASSERT (accept_from);
       ASSERT (sock->info.proto == PROTO_TCPv4_SERVER);
       ASSERT (!sock->inetd);
       sock->sd = accept_from->sd;
     }
 
   if (false)
     ;
 #ifdef ENABLE_HTTP_PROXY
   /* are we running in HTTP proxy mode? */
   else if (sock->http_proxy)
     {
       ASSERT (sock->info.proto == PROTO_TCPv4_CLIENT);
       ASSERT (!sock->inetd);
 
       /* the proxy server */
       sock->remote_host = http_proxy->options.server;
       sock->remote_port = http_proxy->options.port;
 
       /* the OpenVPN server we will use the proxy to connect to */
       sock->proxy_dest_host = remote_host;
       sock->proxy_dest_port = remote_port;
     }
 #endif
 #ifdef ENABLE_SOCKS
   /* or in Socks proxy mode? */
   else if (sock->socks_proxy)
     {
       ASSERT (sock->info.proto == PROTO_TCPv4_CLIENT || sock->info.proto == PROTO_UDPv4);
       ASSERT (!sock->inetd);
 
       /* the proxy server */
       sock->remote_host = socks_proxy->server;
       sock->remote_port = socks_proxy->port;
 
       /* the OpenVPN server we will use the proxy to connect to */
       sock->proxy_dest_host = remote_host;
       sock->proxy_dest_port = remote_port;
     }
 #endif
   else
     {
       sock->remote_host = remote_host;
       sock->remote_port = remote_port;
     }
 
   /* bind behavior for TCP server vs. client */
   if (sock->info.proto == PROTO_TCPv4_SERVER)
     {
       if (sock->mode == LS_MODE_TCP_ACCEPT_FROM)
 	sock->bind_local = false;
       else
 	sock->bind_local = true;
     }
 
   /* were we started by inetd or xinetd? */
   if (sock->inetd)
     {
       ASSERT (sock->info.proto != PROTO_TCPv4_CLIENT);
       ASSERT (socket_defined (inetd_socket_descriptor));
       sock->sd = inetd_socket_descriptor;
     }
   else if (mode != LS_MODE_TCP_ACCEPT_FROM)
     {
       create_socket (sock);
       resolve_bind_local (sock);
       resolve_remote (sock, 1, NULL, NULL);
     }
 }
 
 /* finalize socket initialization */
 void
 link_socket_init_phase2 (struct link_socket *sock,
 			 const struct frame *frame,
 			 volatile int *signal_received)
 {
   struct gc_arena gc = gc_new ();
   const char *remote_dynamic = NULL;
   bool remote_changed = false;

   int sig_save = 0;

 
   ASSERT (sock);
 

   if (signal_received && *signal_received)
     {
       sig_save = *signal_received;
       *signal_received = 0;
     }
 

   /* initialize buffers */
   socket_frame_init (frame, sock);
 
   /*
    * Pass a remote name to connect/accept so that
    * they can test for dynamic IP address changes
    * and throw a SIGUSR1 if appropriate.
    */
   if (sock->resolve_retry_seconds)
     remote_dynamic = sock->remote_host;
 
   /* were we started by inetd or xinetd? */
   if (sock->inetd)
     {
       if (sock->info.proto == PROTO_TCPv4_SERVER)
 	sock->sd =
 	  socket_listen_accept (sock->sd,
 				&sock->info.lsa->actual,
 				remote_dynamic,
 				&remote_changed,
 				&sock->info.lsa->local,
 				false,
 				sock->inetd == INETD_NOWAIT,
 				signal_received);
       ASSERT (!remote_changed);
       if (*signal_received)
 	goto done;
     }
   else
     {
       resolve_remote (sock, 2, &remote_dynamic, signal_received);
 
       if (*signal_received)
 	goto done;
 
       /* TCP client/server */
       if (sock->info.proto == PROTO_TCPv4_SERVER)
 	{
 	  switch (sock->mode)
 	    {
 	    case LS_MODE_DEFAULT:
 	      sock->sd = socket_listen_accept (sock->sd,
 					       &sock->info.lsa->actual,
 					       remote_dynamic,
 					       &remote_changed,
 					       &sock->info.lsa->local,
 					       true,
 					       false,
 					       signal_received);
 	      break;
 	    case LS_MODE_TCP_LISTEN:
 	      socket_do_listen (sock->sd,
 				&sock->info.lsa->local,
 				true,
 				false);
 	      break;
 	    case LS_MODE_TCP_ACCEPT_FROM:
 	      sock->sd = socket_do_accept (sock->sd,
 					   &sock->info.lsa->actual,
 					   false);
 	      if (!socket_defined (sock->sd))
 		{
 		  *signal_received = SIGTERM;
 		  goto done;
 		}
 	      tcp_connection_established (&sock->info.lsa->actual);
 	      break;
 	    default:
 	      ASSERT (0);
 	    }
 	}
       else if (sock->info.proto == PROTO_TCPv4_CLIENT)
 	{
 

 #ifdef GENERAL_PROXY_SUPPORT
 	  bool proxy_retry = false;
 #else
 	  const bool proxy_retry = false;
 #endif
 	  do {
 	    socket_connect (&sock->sd,
 			    &sock->info.lsa->local,
 			    sock->bind_local,
 			    &sock->info.lsa->actual.dest,

 			    sock->connection_profiles_defined,

 			    remote_dynamic,
 			    &remote_changed,
 			    sock->connect_retry_seconds,
 			    sock->connect_timeout,
 			    sock->connect_retry_max,
 			    signal_received);
 
 	    if (*signal_received)
 	      goto done;
 
 	    if (false)
 	      ;

 #ifdef ENABLE_HTTP_PROXY

 	    else if (sock->http_proxy)
 	      {
 		proxy_retry = establish_http_proxy_passthru (sock->http_proxy,
 							     sock->sd,
 							     sock->proxy_dest_host,
 							     sock->proxy_dest_port,
 							     &sock->stream_buf.residual,
 							     signal_received);
 	      }

 #endif
 #ifdef ENABLE_SOCKS

 	    else if (sock->socks_proxy)
 	      {
 		establish_socks_proxy_passthru (sock->socks_proxy,
 						sock->sd,
 						sock->proxy_dest_host,
 						sock->proxy_dest_port,
 						signal_received);
 	      }

 #endif

 	    if (proxy_retry)
 	      {
 		openvpn_close_socket (sock->sd);
 		sock->sd = create_socket_tcp ();
 	      }
 	  } while (proxy_retry);

 	}
 #ifdef ENABLE_SOCKS
       else if (sock->info.proto == PROTO_UDPv4 && sock->socks_proxy)
 	{
 	  socket_connect (&sock->ctrl_sd,

                           &sock->info.lsa->local,
                           sock->bind_local,

 			  &sock->info.lsa->actual.dest,

 			  sock->connection_profiles_defined,

 			  remote_dynamic,
 			  &remote_changed,
 			  sock->connect_retry_seconds,

 			  sock->connect_timeout,

 			  sock->connect_retry_max,

 			  signal_received);
 
 	  if (*signal_received)
 	    goto done;
 
 	  establish_socks_proxy_udpassoc (sock->socks_proxy,
 					  sock->ctrl_sd,

 					  sock->sd,
 					  &sock->socks_relay.dest,

 					  signal_received);
 
 	  if (*signal_received)
 	    goto done;
 
 	  sock->remote_host = sock->proxy_dest_host;
 	  sock->remote_port = sock->proxy_dest_port;
 	  sock->did_resolve_remote = false;

 
 	  sock->info.lsa->actual.dest.sa.sin_addr.s_addr = 0;
 	  sock->info.lsa->remote.sa.sin_addr.s_addr = 0;

 
 	  resolve_remote (sock, 1, NULL, signal_received);
 
 	  if (*signal_received)
 	    goto done;
 	}
 #endif

       if (*signal_received)
 	goto done;
 
       if (remote_changed)
 	{
 	  msg (M_INFO, "TCP/UDP: Dynamic remote address changed during TCP connection establishment");

 	  sock->info.lsa->remote.sa.sin_addr.s_addr = sock->info.lsa->actual.dest.sa.sin_addr.s_addr;

 	}
     }
 
   /* set socket buffers based on --sndbuf and --rcvbuf options */
   socket_set_buffers (sock->sd, &sock->socket_buffer_sizes);
 

   /* set misc socket parameters */
   socket_set_flags (sock->sd, sock->sockflags);
 

   /* set socket to non-blocking mode */
   set_nonblock (sock->sd);
 
   /* set socket file descriptor to not pass across execs, so that
      scripts don't have access to it */
   set_cloexec (sock->sd);
 
 #ifdef ENABLE_SOCKS
   if (socket_defined (sock->ctrl_sd))
     set_cloexec (sock->ctrl_sd);
 #endif
 
   /* set Path MTU discovery options on the socket */
   set_mtu_discover_type (sock->sd, sock->mtu_discover_type);
 
 #if EXTENDED_SOCKET_ERROR_CAPABILITY
   /* if the OS supports it, enable extended error passing on the socket */
   set_sock_extended_error_passing (sock->sd);
 #endif
 
   /* print local address */
   if (sock->inetd)
     msg (M_INFO, "%s link local: [inetd]", proto2ascii (sock->info.proto, true));
   else
     msg (M_INFO, "%s link local%s: %s",
 	 proto2ascii (sock->info.proto, true),
 	 (sock->bind_local ? " (bound)" : ""),

 	 print_sockaddr_ex (&sock->info.lsa->local, ":", sock->bind_local ? PS_SHOW_PORT : 0, &gc));

 
   /* print active remote address */
   msg (M_INFO, "%s link remote: %s",
        proto2ascii (sock->info.proto, true),

        print_link_socket_actual_ex (&sock->info.lsa->actual,
 				    ":",
 				    PS_SHOW_PORT_IF_DEFINED,
 				    &gc));

 
  done:

   if (sig_save && signal_received)
     {
       if (!*signal_received)
 	*signal_received = sig_save;
     }

   gc_free (&gc);
 }
 
 void
 link_socket_close (struct link_socket *sock)
 {
   if (sock)
     {
 #ifdef ENABLE_DEBUG
       const int gremlin = GREMLIN_CONNECTION_FLOOD_LEVEL (sock->gremlin);
 #else
       const int gremlin = 0;
 #endif
 
       if (socket_defined (sock->sd))
 	{
 #ifdef WIN32
 	  close_net_event_win32 (&sock->listen_handle, sock->sd, 0);
 #endif
 	  if (!gremlin)
 	    {
 	      msg (D_CLOSE, "TCP/UDP: Closing socket");
 	      if (openvpn_close_socket (sock->sd))
 		msg (M_WARN | M_ERRNO_SOCK, "TCP/UDP: Close Socket failed");
 	    }
 	  sock->sd = SOCKET_UNDEFINED;
 #ifdef WIN32
 	  if (!gremlin)
 	    {
 	      overlapped_io_close (&sock->reads);
 	      overlapped_io_close (&sock->writes);
 	    }
 #endif
 	}
 
 #ifdef ENABLE_SOCKS
       if (socket_defined (sock->ctrl_sd))
 	{
 	  if (openvpn_close_socket (sock->ctrl_sd))
 	    msg (M_WARN | M_ERRNO_SOCK, "TCP/UDP: Close Socket (ctrl_sd) failed");
 	  sock->ctrl_sd = SOCKET_UNDEFINED;
 	}
 #endif
 
       stream_buf_close (&sock->stream_buf);
       free_buf (&sock->stream_buf_data);
       if (!gremlin)
 	free (sock);
     }
 }
 
 /* for stream protocols, allow for packet length prefix */
 void
 socket_adjust_frame_parameters (struct frame *frame, int proto)
 {
   if (link_socket_proto_connection_oriented (proto))
     frame_add_to_extra_frame (frame, sizeof (packet_size_type));
 }
 
 void
 setenv_trusted (struct env_set *es, const struct link_socket_info *info)
 {

   setenv_link_socket_actual (es, "trusted", &info->lsa->actual, SA_IP_PORT);

 }
 

 static void
 ipchange_fmt (const bool include_cmd, struct argv *argv, const struct link_socket_info *info, struct gc_arena *gc)
 {
   const char *ip = print_sockaddr_ex (&info->lsa->actual.dest, NULL, 0, gc);
   const char *port = print_sockaddr_ex (&info->lsa->actual.dest, NULL, PS_DONT_SHOW_ADDR|PS_SHOW_PORT, gc);
   if (include_cmd)

     argv_printf (argv, "%sc %s %s",

 		 info->ipchange_command,
 		 ip,
 		 port);
   else
     argv_printf (argv, "%s %s",
 		 ip,
 		 port);
 }
 

 void
 link_socket_connection_initiated (const struct buffer *buf,
 				  struct link_socket_info *info,

 				  const struct link_socket_actual *act,

 				  const char *common_name,
 				  struct env_set *es)
 {
   struct gc_arena gc = gc_new ();
   

   info->lsa->actual = *act; /* Note: skip this line for --force-dest */

   setenv_trusted (es, info);
   info->connection_established = true;
 
   /* Print connection initiated message, with common name if available */
   {
     struct buffer out = alloc_buf_gc (256, &gc);
     if (common_name)
       buf_printf (&out, "[%s] ", common_name);

     buf_printf (&out, "Peer Connection Initiated with %s", print_link_socket_actual (&info->lsa->actual, &gc));

     msg (M_INFO, "%s", BSTR (&out));
   }
 
   /* set environmental vars */
   setenv_str (es, "common_name", common_name);
 
   /* Process --ipchange plugin */
   if (plugin_defined (info->plugins, OPENVPN_PLUGIN_IPCHANGE))
     {

       struct argv argv = argv_new ();
       ipchange_fmt (false, &argv, info, &gc);
       if (plugin_call (info->plugins, OPENVPN_PLUGIN_IPCHANGE, &argv, NULL, es) != OPENVPN_PLUGIN_FUNC_SUCCESS)

 	msg (M_WARN, "WARNING: ipchange plugin call failed");

       argv_reset (&argv);

     }
 
   /* Process --ipchange option */
   if (info->ipchange_command)
     {

       struct argv argv = argv_new ();

       setenv_str (es, "script_type", "ipchange");

       ipchange_fmt (true, &argv, info, &gc);
       openvpn_execve_check (&argv, es, S_SCRIPT, "ip-change command failed");
       argv_reset (&argv);

     }
 
   gc_free (&gc);
 }
 
 void
 link_socket_bad_incoming_addr (struct buffer *buf,
 			       const struct link_socket_info *info,

 			       const struct link_socket_actual *from_addr)

 {
   struct gc_arena gc = gc_new ();
 
   msg (D_LINK_ERRORS,
        "TCP/UDP: Incoming packet rejected from %s[%d], expected peer address: %s (allow this incoming source address/port by removing --remote or adding --float)",

        print_link_socket_actual (from_addr, &gc),
        (int)from_addr->dest.sa.sin_family,

        print_sockaddr (&info->lsa->remote, &gc));
   buf->len = 0;
 
   gc_free (&gc);
 }
 
 void
 link_socket_bad_outgoing_addr (void)
 {
   dmsg (D_READ_WRITE, "TCP/UDP: No outgoing address to send packet");
 }
 
 in_addr_t
 link_socket_current_remote (const struct link_socket_info *info)
 {
   const struct link_socket_addr *lsa = info->lsa;
 

   if (link_socket_actual_defined (&lsa->actual))
     return ntohl (lsa->actual.dest.sa.sin_addr.s_addr);

   else if (addr_defined (&lsa->remote))

     return ntohl (lsa->remote.sa.sin_addr.s_addr);

   else
     return 0;
 }
 
 /*
  * Return a status string describing socket state.
  */
 const char *
 socket_stat (const struct link_socket *s, unsigned int rwflags, struct gc_arena *gc)
 {
   struct buffer out = alloc_buf_gc (64, gc);
   if (s)
     {
       if (rwflags & EVENT_READ)
 	{
 	  buf_printf (&out, "S%s",
 		      (s->rwflags_debug & EVENT_READ) ? "R" : "r");
 #ifdef WIN32
 	  buf_printf (&out, "%s",
 		      overlapped_io_state_ascii (&s->reads));
 #endif
 	}
       if (rwflags & EVENT_WRITE)
 	{
 	  buf_printf (&out, "S%s",
 		      (s->rwflags_debug & EVENT_WRITE) ? "W" : "w");
 #ifdef WIN32
 	  buf_printf (&out, "%s",
 		      overlapped_io_state_ascii (&s->writes));
 #endif
 	}
     }
   else
     {
       buf_printf (&out, "S?");
     }
   return BSTR (&out);
 }
 
 /*
  * Stream buffer functions, used to packetize a TCP
  * stream connection.
  */
 
 static inline void
 stream_buf_reset (struct stream_buf *sb)
 {
   dmsg (D_STREAM_DEBUG, "STREAM: RESET");
   sb->residual_fully_formed = false;
   sb->buf = sb->buf_init;
   buf_reset (&sb->next);
   sb->len = -1;
 }
 
 void
 stream_buf_init (struct stream_buf *sb,

 		 struct buffer *buf,
 		 const unsigned int sockflags,
 		 const int proto)

 {
   sb->buf_init = *buf;
   sb->maxlen = sb->buf_init.len;
   sb->buf_init.len = 0;
   sb->residual = alloc_buf (sb->maxlen);
   sb->error = false;

 #if PORT_SHARE

   sb->port_share_state = ((sockflags & SF_PORT_SHARE) && (proto == PROTO_TCPv4_SERVER))
     ? PS_ENABLED
     : PS_DISABLED;

 #endif

   stream_buf_reset (sb);
 
   dmsg (D_STREAM_DEBUG, "STREAM: INIT maxlen=%d", sb->maxlen);
 }
 
 static inline void
 stream_buf_set_next (struct stream_buf *sb)
 {
   /* set up 'next' for next i/o read */
   sb->next = sb->buf;
   sb->next.offset = sb->buf.offset + sb->buf.len;
   sb->next.len = (sb->len >= 0 ? sb->len : sb->maxlen) - sb->buf.len;
   dmsg (D_STREAM_DEBUG, "STREAM: SET NEXT, buf=[%d,%d] next=[%d,%d] len=%d maxlen=%d",
        sb->buf.offset, sb->buf.len,
        sb->next.offset, sb->next.len,
        sb->len, sb->maxlen);
   ASSERT (sb->next.len > 0);
   ASSERT (buf_safe (&sb->buf, sb->next.len));
 }
 
 static inline void
 stream_buf_get_final (struct stream_buf *sb, struct buffer *buf)
 {
   dmsg (D_STREAM_DEBUG, "STREAM: GET FINAL len=%d",
        buf_defined (&sb->buf) ? sb->buf.len : -1);
   ASSERT (buf_defined (&sb->buf));
   *buf = sb->buf;
 }
 
 static inline void
 stream_buf_get_next (struct stream_buf *sb, struct buffer *buf)
 {
   dmsg (D_STREAM_DEBUG, "STREAM: GET NEXT len=%d",
        buf_defined (&sb->next) ? sb->next.len : -1);
   ASSERT (buf_defined (&sb->next));
   *buf = sb->next;
 }
 
 bool
 stream_buf_read_setup_dowork (struct link_socket* sock)
 {
   if (sock->stream_buf.residual.len && !sock->stream_buf.residual_fully_formed)
     {
       ASSERT (buf_copy (&sock->stream_buf.buf, &sock->stream_buf.residual));
       ASSERT (buf_init (&sock->stream_buf.residual, 0));
       sock->stream_buf.residual_fully_formed = stream_buf_added (&sock->stream_buf, 0);
       dmsg (D_STREAM_DEBUG, "STREAM: RESIDUAL FULLY FORMED [%s], len=%d",
 	   sock->stream_buf.residual_fully_formed ? "YES" : "NO",
 	   sock->stream_buf.residual.len);
     }
 
   if (!sock->stream_buf.residual_fully_formed)
     stream_buf_set_next (&sock->stream_buf);
   return !sock->stream_buf.residual_fully_formed;
 }
 
 bool
 stream_buf_added (struct stream_buf *sb,
 		  int length_added)
 {
   dmsg (D_STREAM_DEBUG, "STREAM: ADD length_added=%d", length_added);
   if (length_added > 0)
     sb->buf.len += length_added;
 
   /* if length unknown, see if we can get the length prefix from
      the head of the buffer */
   if (sb->len < 0 && sb->buf.len >= (int) sizeof (packet_size_type))
     {
       packet_size_type net_size;

 
 #if PORT_SHARE
       if (sb->port_share_state == PS_ENABLED)
 	{
 	  if (!is_openvpn_protocol (&sb->buf))
 	    {

 	      msg (D_STREAM_ERRORS, "Non-OpenVPN client protocol detected");

 	      sb->port_share_state = PS_FOREIGN;
 	      sb->error = true;
 	      return false;
 	    }
 	  else
 	    sb->port_share_state = PS_DISABLED;
 	}
 #endif
 

       ASSERT (buf_read (&sb->buf, &net_size, sizeof (net_size)));
       sb->len = ntohps (net_size);
 
       if (sb->len < 1 || sb->len > sb->maxlen)
 	{
 	  msg (M_WARN, "WARNING: Bad encapsulated packet length from peer (%d), which must be > 0 and <= %d -- please ensure that --tun-mtu or --link-mtu is equal on both peers -- this condition could also indicate a possible active attack on the TCP link -- [Attemping restart...]", sb->len, sb->maxlen);
 	  stream_buf_reset (sb);
 	  sb->error = true;
 	  return false;
 	}
     }
 
   /* is our incoming packet fully read? */
   if (sb->len > 0 && sb->buf.len >= sb->len)
     {
       /* save any residual data that's part of the next packet */
       ASSERT (buf_init (&sb->residual, 0));
       if (sb->buf.len > sb->len)
 	  ASSERT (buf_copy_excess (&sb->residual, &sb->buf, sb->len));
       dmsg (D_STREAM_DEBUG, "STREAM: ADD returned TRUE, buf_len=%d, residual_len=%d",
 	   BLEN (&sb->buf),
 	   BLEN (&sb->residual));
       return true;
     }
   else
     {
       dmsg (D_STREAM_DEBUG, "STREAM: ADD returned FALSE (have=%d need=%d)", sb->buf.len, sb->len);
       stream_buf_set_next (sb);
       return false;
     }
 }
 
 void
 stream_buf_close (struct stream_buf* sb)
 {
   free_buf (&sb->residual);
 }
 
 /*
  * The listen event is a special event whose sole purpose is
  * to tell us that there's a new incoming connection on a
  * TCP socket, for use in server mode.
  */
 event_t
 socket_listen_event_handle (struct link_socket *s)
 {
 #ifdef WIN32
   if (!defined_net_event_win32 (&s->listen_handle))
     init_net_event_win32 (&s->listen_handle, FD_ACCEPT, s->sd, 0);
   return &s->listen_handle;
 #else
   return s->sd;
 #endif
 }
 
 /*
  * Format IP addresses in ascii
  */
 
 const char *

 print_sockaddr (const struct openvpn_sockaddr *addr, struct gc_arena *gc)

 {

   return print_sockaddr_ex (addr, ":", PS_SHOW_PORT, gc);

 }
 
 const char *

 print_sockaddr_ex (const struct openvpn_sockaddr *addr,
 		   const char* separator,
 		   const unsigned int flags,
 		   struct gc_arena *gc)

 {

   if (addr)
     {
       struct buffer out = alloc_buf_gc (64, gc);
       const int port = ntohs (addr->sa.sin_port);

       mutex_lock_static (L_INET_NTOA);

       if (!(flags & PS_DONT_SHOW_ADDR))
 	buf_printf (&out, "%s", (addr_defined (addr) ? inet_ntoa (addr->sa.sin_addr) : "[undef]"));

       mutex_unlock_static (L_INET_NTOA);

       if (((flags & PS_SHOW_PORT) || (addr_defined (addr) && (flags & PS_SHOW_PORT_IF_DEFINED)))
 	  && port)
 	{
 	  if (separator)
 	    buf_printf (&out, "%s", separator);

 	  buf_printf (&out, "%d", port);
 	}
       return BSTR (&out);

     }

   else
     return "[NULL]";
 }
 
 const char *
 print_link_socket_actual (const struct link_socket_actual *act, struct gc_arena *gc)
 {
   return print_link_socket_actual_ex (act, ":", PS_SHOW_PORT|PS_SHOW_PKTINFO, gc);
 }
 
 const char *
 print_link_socket_actual_ex (const struct link_socket_actual *act,
 			     const char *separator,
 			     const unsigned int flags,
 			     struct gc_arena *gc)
 {
   if (act)
     {
       struct buffer out = alloc_buf_gc (128, gc);
       buf_printf (&out, "%s", print_sockaddr_ex (&act->dest, separator, flags, gc));
 #if ENABLE_IP_PKTINFO
       if ((flags & PS_SHOW_PKTINFO) && act->pi.ipi_spec_dst.s_addr)
 	{
 	  struct openvpn_sockaddr sa;
 	  CLEAR (sa);
 	  sa.sa.sin_addr = act->pi.ipi_spec_dst;
 	  buf_printf (&out, " (via %s)", print_sockaddr_ex (&sa, separator, 0, gc));
 	}
 #endif
       return BSTR (&out);
     }
   else
     return "[NULL]";

 }
 
 /*
  * Convert an in_addr_t in host byte order
  * to an ascii dotted quad.
  */
 const char *
 print_in_addr_t (in_addr_t addr, unsigned int flags, struct gc_arena *gc)
 {
   struct in_addr ia;
   struct buffer out = alloc_buf_gc (64, gc);
 
   if (addr || !(flags & IA_EMPTY_IF_UNDEF))
     {
       CLEAR (ia);
       ia.s_addr = (flags & IA_NET_ORDER) ? addr : htonl (addr);
 
       mutex_lock_static (L_INET_NTOA);
       buf_printf (&out, "%s", inet_ntoa (ia));
       mutex_unlock_static (L_INET_NTOA);
     }
   return BSTR (&out);
 }
 
 /* set environmental variables for ip/port in *addr */
 void

 setenv_sockaddr (struct env_set *es, const char *name_prefix, const struct openvpn_sockaddr *addr, const bool flags)

 {
   char name_buf[256];
 
   if (flags & SA_IP_PORT)
     openvpn_snprintf (name_buf, sizeof (name_buf), "%s_ip", name_prefix);
   else
     openvpn_snprintf (name_buf, sizeof (name_buf), "%s", name_prefix);
 
   mutex_lock_static (L_INET_NTOA);

   setenv_str (es, name_buf, inet_ntoa (addr->sa.sin_addr));

   mutex_unlock_static (L_INET_NTOA);
 

   if ((flags & SA_IP_PORT) && addr->sa.sin_port)

     {
       openvpn_snprintf (name_buf, sizeof (name_buf), "%s_port", name_prefix);

       setenv_int (es, name_buf, ntohs (addr->sa.sin_port));

     }
 }
 
 void
 setenv_in_addr_t (struct env_set *es, const char *name_prefix, in_addr_t addr, const bool flags)
 {
   if (addr || !(flags & SA_SET_IF_NONZERO))
     {

       struct openvpn_sockaddr si;

       CLEAR (si);

       si.sa.sin_addr.s_addr = htonl (addr);

       setenv_sockaddr (es, name_prefix, &si, flags);
     }
 }
 

 void
 setenv_link_socket_actual (struct env_set *es,
 			   const char *name_prefix,
 			   const struct link_socket_actual *act,
 			   const bool flags)
 {
   setenv_sockaddr (es, name_prefix, &act->dest, flags);
 }
 

 /*
  * Convert protocol names between index and ascii form.
  */
 
 struct proto_names {
   const char *short_form;
   const char *display_form;
 };
 
 /* Indexed by PROTO_x */
 static const struct proto_names proto_names[] = {
   {"udp",        "UDPv4"},
   {"tcp-server", "TCPv4_SERVER"},
   {"tcp-client", "TCPv4_CLIENT"},
   {"tcp",        "TCPv4"}
 };
 
 int
 ascii2proto (const char* proto_name)
 {
   int i;
   ASSERT (PROTO_N == SIZE (proto_names));
   for (i = 0; i < PROTO_N; ++i)
     if (!strcmp (proto_name, proto_names[i].short_form))
       return i;
   return -1;
 }
 
 const char *
 proto2ascii (int proto, bool display_form)
 {
   ASSERT (PROTO_N == SIZE (proto_names));
   if (proto < 0 || proto >= PROTO_N)
     return "[unknown protocol]";
   else if (display_form)
     return proto_names[proto].display_form;
   else
     return proto_names[proto].short_form;
 }
 
 const char *
 proto2ascii_all (struct gc_arena *gc)
 {
   struct buffer out = alloc_buf_gc (256, gc);
   int i;
 
   ASSERT (PROTO_N == SIZE (proto_names));
   for (i = 0; i < PROTO_N; ++i)
     {
       if (i)
 	buf_printf(&out, " ");
       buf_printf(&out, "[%s]", proto2ascii(i, false));
     }
   return BSTR (&out);
 }
 
 /*
  * Given a local proto, return local proto
  * if !remote, or compatible remote proto
  * if remote.
  *
  * This is used for options compatibility
  * checking.
  */
 int
 proto_remote (int proto, bool remote)
 {
   ASSERT (proto >= 0 && proto < PROTO_N);
   if (remote)
     {
       if (proto == PROTO_TCPv4_SERVER)
 	return PROTO_TCPv4_CLIENT;
       if (proto == PROTO_TCPv4_CLIENT)
 	return PROTO_TCPv4_SERVER;
     }
   return proto;
 }
 
 /*
  * Bad incoming address lengths that differ from what
  * we expect are considered to be fatal errors.
  */
 void
 bad_address_length (int actual, int expected)
 {
   msg (M_FATAL, "ERROR: received strange incoming packet with an address length of %d -- we only accept address lengths of %d.",
        actual,
        expected);
 }
 
 /*
  * Socket Read Routines
  */
 
 int
 link_socket_read_tcp (struct link_socket *sock,
 		      struct buffer *buf)
 {
   int len = 0;
 
   if (!sock->stream_buf.residual_fully_formed)
     {
 #ifdef WIN32
       len = socket_finalize (sock->sd, &sock->reads, buf, NULL);
 #else
       struct buffer frag;
       stream_buf_get_next (&sock->stream_buf, &frag);
       len = recv (sock->sd, BPTR (&frag), BLEN (&frag), MSG_NOSIGNAL);
 #endif
 
       if (!len)
 	sock->stream_reset = true;
       if (len <= 0)
 	return buf->len = len;
     }
 
   if (sock->stream_buf.residual_fully_formed
       || stream_buf_added (&sock->stream_buf, len)) /* packet complete? */
     {
       stream_buf_get_final (&sock->stream_buf, buf);
       stream_buf_reset (&sock->stream_buf);
       return buf->len;
     }
   else
     return buf->len = 0; /* no error, but packet is still incomplete */
 }
 
 #ifndef WIN32
 

 #if ENABLE_IP_PKTINFO
 

 #pragma pack(1) /* needed to keep structure size consistent for 32 vs. 64-bit architectures */

 struct openvpn_pktinfo
 {
   struct cmsghdr cmsghdr;
   struct in_pktinfo in_pktinfo;
 };

 #pragma pack()

 
 static socklen_t
 link_socket_read_udp_posix_recvmsg (struct link_socket *sock,
 				    struct buffer *buf,
 				    int maxsize,
 				    struct link_socket_actual *from)
 {
   struct iovec iov;
   struct openvpn_pktinfo opi;
   struct msghdr mesg;
   socklen_t fromlen = sizeof (from->dest.sa);
 
   iov.iov_base = BPTR (buf);
   iov.iov_len = maxsize;
   mesg.msg_iov = &iov;
   mesg.msg_iovlen = 1;
   mesg.msg_name = &from->dest.sa;
   mesg.msg_namelen = fromlen;
   mesg.msg_control = &opi;
   mesg.msg_controllen = sizeof (opi);
   buf->len = recvmsg (sock->sd, &mesg, 0);
   if (buf->len >= 0)
     {
       struct cmsghdr *cmsg;
       fromlen = mesg.msg_namelen;
       cmsg = CMSG_FIRSTHDR (&mesg);
       if (cmsg != NULL
 	  && CMSG_NXTHDR (&mesg, cmsg) == NULL
 	  && cmsg->cmsg_level == SOL_IP 
 	  && cmsg->cmsg_type == IP_PKTINFO
 	  && cmsg->cmsg_len >= sizeof (opi))
 	{
 	  struct in_pktinfo *pkti = (struct in_pktinfo *) CMSG_DATA (cmsg);
 	  from->pi.ipi_ifindex = pkti->ipi_ifindex;
 	  from->pi.ipi_spec_dst = pkti->ipi_spec_dst;
 	}
     }
   return fromlen;
 }
 #endif
 

 int
 link_socket_read_udp_posix (struct link_socket *sock,
 			    struct buffer *buf,
 			    int maxsize,

 			    struct link_socket_actual *from)

 {

   socklen_t fromlen = sizeof (from->dest.sa);
   from->dest.sa.sin_addr.s_addr = 0;

   ASSERT (buf_safe (buf, maxsize));

 #if ENABLE_IP_PKTINFO
   if (sock->sockflags & SF_USE_IP_PKTINFO)
     fromlen = link_socket_read_udp_posix_recvmsg (sock, buf, maxsize, from);
   else
 #endif
     buf->len = recvfrom (sock->sd, BPTR (buf), maxsize, 0,
 			 (struct sockaddr *) &from->dest.sa, &fromlen);
   if (fromlen != sizeof (from->dest.sa))
     bad_address_length (fromlen, sizeof (from->dest.sa));

   return buf->len;
 }
 
 #endif
 
 /*
  * Socket Write Routines
  */
 
 int
 link_socket_write_tcp (struct link_socket *sock,
 		       struct buffer *buf,

 		       struct link_socket_actual *to)

 {
   packet_size_type len = BLEN (buf);
   dmsg (D_STREAM_DEBUG, "STREAM: WRITE %d offset=%d", (int)len, buf->offset);
   ASSERT (len <= sock->stream_buf.maxlen);
   len = htonps (len);
   ASSERT (buf_write_prepend (buf, &len, sizeof (len)));
 #ifdef WIN32
   return link_socket_write_win32 (sock, buf, to);
 #else
   return link_socket_write_tcp_posix (sock, buf, to);  
 #endif
 }
 

 #if ENABLE_IP_PKTINFO
 
 int
 link_socket_write_udp_posix_sendmsg (struct link_socket *sock,
 				     struct buffer *buf,
 				     struct link_socket_actual *to)
 {
   struct iovec iov;
   struct msghdr mesg;
   struct cmsghdr *cmsg;
   struct in_pktinfo *pkti;
   struct openvpn_pktinfo opi;
 
   iov.iov_base = BPTR (buf);
   iov.iov_len = BLEN (buf);
   mesg.msg_iov = &iov;
   mesg.msg_iovlen = 1;
   mesg.msg_name = &to->dest.sa;
   mesg.msg_namelen = sizeof (to->dest.sa);
   mesg.msg_control = &opi;
   mesg.msg_controllen = sizeof (opi);
   mesg.msg_flags = 0;
   cmsg = CMSG_FIRSTHDR (&mesg);
   cmsg->cmsg_len = sizeof (opi);
   cmsg->cmsg_level = SOL_IP;
   cmsg->cmsg_type = IP_PKTINFO;
   pkti = (struct in_pktinfo *) CMSG_DATA (cmsg);
   pkti->ipi_ifindex = to->pi.ipi_ifindex;
   pkti->ipi_spec_dst = to->pi.ipi_spec_dst;
   pkti->ipi_addr.s_addr = 0;
   return sendmsg (sock->sd, &mesg, 0);
 }
 
 #endif
 

 /*
  * Win32 overlapped socket I/O functions.
  */
 
 #ifdef WIN32
 
 int
 socket_recv_queue (struct link_socket *sock, int maxsize)
 {
   if (sock->reads.iostate == IOSTATE_INITIAL)
     {
       WSABUF wsabuf[1];
       int status;
 
       /* reset buf to its initial state */
       if (sock->info.proto == PROTO_UDPv4)
 	{
 	  sock->reads.buf = sock->reads.buf_init;
 	}
       else if (sock->info.proto == PROTO_TCPv4_CLIENT || sock->info.proto == PROTO_TCPv4_SERVER)
 	{
 	  stream_buf_get_next (&sock->stream_buf, &sock->reads.buf);
 	}
       else
 	{
 	  ASSERT (0);
 	}
 
       /* Win32 docs say it's okay to allocate the wsabuf on the stack */
       wsabuf[0].buf = BPTR (&sock->reads.buf);
       wsabuf[0].len = maxsize ? maxsize : BLEN (&sock->reads.buf);
 
       /* check for buffer overflow */
       ASSERT (wsabuf[0].len <= BLEN (&sock->reads.buf));
 
       /* the overlapped read will signal this event on I/O completion */
       ASSERT (ResetEvent (sock->reads.overlapped.hEvent));
       sock->reads.flags = 0;
 
       if (sock->info.proto == PROTO_UDPv4)
 	{
 	  sock->reads.addr_defined = true;
 	  sock->reads.addrlen = sizeof (sock->reads.addr);
 	  status = WSARecvFrom(
 			       sock->sd,
 			       wsabuf,
 			       1,
 			       &sock->reads.size,
 			       &sock->reads.flags,
 			       (struct sockaddr *) &sock->reads.addr,
 			       &sock->reads.addrlen,
 			       &sock->reads.overlapped,
 			       NULL);
 	}
       else if (sock->info.proto == PROTO_TCPv4_CLIENT || sock->info.proto == PROTO_TCPv4_SERVER)
 	{
 	  sock->reads.addr_defined = false;
 	  status = WSARecv(
 			   sock->sd,
 			   wsabuf,
 			   1,
 			   &sock->reads.size,
 			   &sock->reads.flags,
 			   &sock->reads.overlapped,
 			   NULL);
 	}
       else
 	{
 	  status = 0;
 	  ASSERT (0);
 	}
 
       if (!status) /* operation completed immediately? */
 	{
 	  if (sock->reads.addr_defined && sock->reads.addrlen != sizeof (sock->reads.addr))
 	    bad_address_length (sock->reads.addrlen, sizeof (sock->reads.addr));
 
 	  sock->reads.iostate = IOSTATE_IMMEDIATE_RETURN;
 
 	  /* since we got an immediate return, we must signal the event object ourselves */
 	  ASSERT (SetEvent (sock->reads.overlapped.hEvent));
 	  sock->reads.status = 0;
 
 	  dmsg (D_WIN32_IO, "WIN32 I/O: Socket Receive immediate return [%d,%d]",
 	       (int) wsabuf[0].len,
 	       (int) sock->reads.size);	       
 	}
       else
 	{
 	  status = WSAGetLastError (); 
 	  if (status == WSA_IO_PENDING) /* operation queued? */
 	    {
 	      sock->reads.iostate = IOSTATE_QUEUED;
 	      sock->reads.status = status;
 	      dmsg (D_WIN32_IO, "WIN32 I/O: Socket Receive queued [%d]",
 		   (int) wsabuf[0].len);
 	    }
 	  else /* error occurred */
 	    {
 	      struct gc_arena gc = gc_new ();
 	      ASSERT (SetEvent (sock->reads.overlapped.hEvent));
 	      sock->reads.iostate = IOSTATE_IMMEDIATE_RETURN;
 	      sock->reads.status = status;
 	      dmsg (D_WIN32_IO, "WIN32 I/O: Socket Receive error [%d]: %s",
 		   (int) wsabuf[0].len,
 		   strerror_win32 (status, &gc));
 	      gc_free (&gc);
 	    }
 	}
     }
   return sock->reads.iostate;
 }
 
 int

 socket_send_queue (struct link_socket *sock, struct buffer *buf, const struct link_socket_actual *to)

 {
   if (sock->writes.iostate == IOSTATE_INITIAL)
     {
       WSABUF wsabuf[1];
       int status;
  
       /* make a private copy of buf */
       sock->writes.buf = sock->writes.buf_init;
       sock->writes.buf.len = 0;
       ASSERT (buf_copy (&sock->writes.buf, buf));
 
       /* Win32 docs say it's okay to allocate the wsabuf on the stack */
       wsabuf[0].buf = BPTR (&sock->writes.buf);
       wsabuf[0].len = BLEN (&sock->writes.buf);
 
       /* the overlapped write will signal this event on I/O completion */
       ASSERT (ResetEvent (sock->writes.overlapped.hEvent));
       sock->writes.flags = 0;
 
       if (sock->info.proto == PROTO_UDPv4)
 	{
 	  /* set destination address for UDP writes */
 	  sock->writes.addr_defined = true;

 	  sock->writes.addr = to->dest.sa;

 	  sock->writes.addrlen = sizeof (sock->writes.addr);
 
 	  status = WSASendTo(
 			       sock->sd,
 			       wsabuf,
 			       1,
 			       &sock->writes.size,
 			       sock->writes.flags,
 			       (struct sockaddr *) &sock->writes.addr,
 			       sock->writes.addrlen,
 			       &sock->writes.overlapped,
 			       NULL);
 	}
       else if (sock->info.proto == PROTO_TCPv4_CLIENT || sock->info.proto == PROTO_TCPv4_SERVER)
 	{
 	  /* destination address for TCP writes was established on connection initiation */
 	  sock->writes.addr_defined = false;
 
 	  status = WSASend(
 			   sock->sd,
 			   wsabuf,
 			   1,
 			   &sock->writes.size,
 			   sock->writes.flags,
 			   &sock->writes.overlapped,
 			   NULL);
 	}
       else 
 	{
 	  status = 0;
 	  ASSERT (0);
 	}
 
       if (!status) /* operation completed immediately? */
 	{
 	  sock->writes.iostate = IOSTATE_IMMEDIATE_RETURN;
 
 	  /* since we got an immediate return, we must signal the event object ourselves */
 	  ASSERT (SetEvent (sock->writes.overlapped.hEvent));
 
 	  sock->writes.status = 0;
 
 	  dmsg (D_WIN32_IO, "WIN32 I/O: Socket Send immediate return [%d,%d]",
 	       (int) wsabuf[0].len,
 	       (int) sock->writes.size);	       
 	}
       else
 	{
 	  status = WSAGetLastError (); 
 	  if (status == WSA_IO_PENDING) /* operation queued? */
 	    {
 	      sock->writes.iostate = IOSTATE_QUEUED;
 	      sock->writes.status = status;
 	      dmsg (D_WIN32_IO, "WIN32 I/O: Socket Send queued [%d]",
 		   (int) wsabuf[0].len);
 	    }
 	  else /* error occurred */
 	    {
 	      struct gc_arena gc = gc_new ();
 	      ASSERT (SetEvent (sock->writes.overlapped.hEvent));
 	      sock->writes.iostate = IOSTATE_IMMEDIATE_RETURN;
 	      sock->writes.status = status;
 
 	      dmsg (D_WIN32_IO, "WIN32 I/O: Socket Send error [%d]: %s",
 		   (int) wsabuf[0].len,
 		   strerror_win32 (status, &gc));
 
 	      gc_free (&gc);
 	    }
 	}
     }
   return sock->writes.iostate;
 }
 
 int

 socket_finalize (SOCKET s,

 		 struct overlapped_io *io,
 		 struct buffer *buf,

 		 struct link_socket_actual *from)

 {
   int ret = -1;
   BOOL status;
 
   switch (io->iostate)
     {
     case IOSTATE_QUEUED:
       status = WSAGetOverlappedResult(
 				      s,
 				      &io->overlapped,
 				      &io->size,
 				      FALSE,
 				      &io->flags
 				      );
       if (status)
 	{
 	  /* successful return for a queued operation */
 	  if (buf)
 	    *buf = io->buf;
 	  ret = io->size;
 	  io->iostate = IOSTATE_INITIAL;
 	  ASSERT (ResetEvent (io->overlapped.hEvent));
 
 	  dmsg (D_WIN32_IO, "WIN32 I/O: Socket Completion success [%d]", ret);
 	}
       else
 	{
 	  /* error during a queued operation */
 	  ret = -1;
 	  if (WSAGetLastError() != WSA_IO_INCOMPLETE)
 	    {
 	      /* if no error (i.e. just not finished yet), then DON'T execute this code */
 	      io->iostate = IOSTATE_INITIAL;
 	      ASSERT (ResetEvent (io->overlapped.hEvent));
 	      msg (D_WIN32_IO | M_ERRNO_SOCK, "WIN32 I/O: Socket Completion error");
 	    }
 	}
       break;
 
     case IOSTATE_IMMEDIATE_RETURN:
       io->iostate = IOSTATE_INITIAL;
       ASSERT (ResetEvent (io->overlapped.hEvent));
       if (io->status)
 	{
 	  /* error return for a non-queued operation */
 	  WSASetLastError (io->status);
 	  ret = -1;
 	  msg (D_WIN32_IO | M_ERRNO_SOCK, "WIN32 I/O: Socket Completion non-queued error");
 	}
       else
 	{
 	  /* successful return for a non-queued operation */
 	  if (buf)
 	    *buf = io->buf;
 	  ret = io->size;
 	  dmsg (D_WIN32_IO, "WIN32 I/O: Socket Completion non-queued success [%d]", ret);
 	}
       break;
 
     case IOSTATE_INITIAL: /* were we called without proper queueing? */
       WSASetLastError (WSAEINVAL);
       ret = -1;
       dmsg (D_WIN32_IO, "WIN32 I/O: Socket Completion BAD STATE");
       break;
 
     default:
       ASSERT (0);
     }
   
   /* return from address if requested */
   if (from)
     {
       if (ret >= 0 && io->addr_defined)
 	{
 	  if (io->addrlen != sizeof (io->addr))
 	    bad_address_length (io->addrlen, sizeof (io->addr));

 	  from->dest.sa = io->addr;

 	}
       else

 	CLEAR (from->dest.sa);

     }
   
   if (buf)
     buf->len = ret;
   return ret;
 }
 
 #endif /* WIN32 */
 
 /*
  * Socket event notification
  */
 
 unsigned int
 socket_set (struct link_socket *s,
 	    struct event_set *es,
 	    unsigned int rwflags,
 	    void *arg,
 	    unsigned int *persistent)
 {
   if (s)
     {
       if ((rwflags & EVENT_READ) && !stream_buf_read_setup (s))
 	{
 	  ASSERT (!persistent);
 	  rwflags &= ~EVENT_READ;
 	}
       
 #ifdef WIN32
       if (rwflags & EVENT_READ)
 	socket_recv_queue (s, 0);
 #endif
 
       /* if persistent is defined, call event_ctl only if rwflags has changed since last call */
       if (!persistent || *persistent != rwflags)
 	{
 	  event_ctl (es, socket_event_handle (s), rwflags, arg);
 	  if (persistent)
 	    *persistent = rwflags;
 	}
 
       s->rwflags_debug = rwflags;
     }
   return rwflags;
 }

 
 void
 sd_close (socket_descriptor_t *sd)
 {
   if (sd && socket_defined (*sd))
     {
       openvpn_close_socket (*sd);
       *sd = SOCKET_UNDEFINED;
     }
 }
 
 #if UNIX_SOCK_SUPPORT
 
 /*
  * code for unix domain sockets
  */
 
 const char *
 sockaddr_unix_name (const struct sockaddr_un *local, const char *null)
 {
   if (local && local->sun_family == PF_UNIX)
     return local->sun_path;
   else
     return null;
 }
 
 socket_descriptor_t
 create_socket_unix (void)
 {
   socket_descriptor_t sd;
 
   if ((sd = socket (PF_UNIX, SOCK_STREAM, 0)) < 0)
     msg (M_SOCKERR, "Cannot create unix domain socket");
   return sd;
 }
 
 void
 socket_bind_unix (socket_descriptor_t sd,
 		  struct sockaddr_un *local,
 		  const char *prefix)
 {
   struct gc_arena gc = gc_new ();
 
 #ifdef HAVE_UMASK
   const mode_t orig_umask = umask (0);
 #endif
 
   if (bind (sd, (struct sockaddr *) local, sizeof (struct sockaddr_un)))
     {
       const int errnum = openvpn_errno_socket ();
       msg (M_FATAL, "%s: Socket bind[%d] failed on unix domain socket %s: %s",
 	   prefix,
 	   (int)sd,
            sockaddr_unix_name (local, "NULL"),
            strerror_ts (errnum, &gc));
     }
 
 #ifdef HAVE_UMASK
   umask (orig_umask);
 #endif
 
   gc_free (&gc);
 }
 
 socket_descriptor_t
 socket_accept_unix (socket_descriptor_t sd,
 		    struct sockaddr_un *remote)
 {
   socklen_t remote_len = sizeof (struct sockaddr_un);
   socket_descriptor_t ret;
 
   CLEAR (*remote);
   ret = accept (sd, (struct sockaddr *) remote, &remote_len);
   return ret;
 }
 

 int
 socket_connect_unix (socket_descriptor_t sd,
 		     struct sockaddr_un *remote)
 {
   int status = connect (sd, (struct sockaddr *) remote, sizeof (struct sockaddr_un));
   if (status)
     status = openvpn_errno_socket ();
   return status;
 }
 

 void
 sockaddr_unix_init (struct sockaddr_un *local, const char *path)
 {
   local->sun_family = PF_UNIX;
   strncpynt (local->sun_path, path, sizeof (local->sun_path));
 }
 
 void
 socket_delete_unix (const struct sockaddr_un *local)
 {
   const char *name = sockaddr_unix_name (local, NULL);
 #ifdef HAVE_UNLINK
   if (name && strlen (name))
     unlink (name);
 #endif
 }
 
 bool
 unix_socket_get_peer_uid_gid (const socket_descriptor_t sd, int *uid, int *gid)
 {
 #ifdef HAVE_GETPEEREID
   uid_t u;
   gid_t g;
   if (getpeereid (sd, &u, &g) == -1) 
     return false;
   if (uid)
     *uid = u;
   if (gid)
     *gid = g;
   return true;
 #elif defined(SO_PEERCRED)
   struct ucred peercred;
   socklen_t so_len = sizeof(peercred);
   if (getsockopt(sd, SOL_SOCKET, SO_PEERCRED, &peercred, &so_len) == -1) 
     return false;
   if (uid)
     *uid = peercred.uid;
   if (gid)
     *gid = peercred.gid;
   return true;
 #else
   return false;
 #endif
 }
 
 #endif