This is the start of the BETA21 branch.

It includes the --topology feature, and
TAP-Win32 driver changes to allow
non-admin access.



git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@580 e7ae566f-a301-0410-adde-c780ea21d3b5

1 files changed, 1776 insertions, 0 deletions

diff --git a/route.c b/route.c
new file mode 100644
index 0000000..2c27eaf
--- /dev/null
+++ b/route.c
@@ -0,0 +1,1776 @@
+/*
+ *  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) 2002-2005 OpenVPN Solutions LLC <info@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
+ */
+
+/*
+ * Support routines for adding/deleting network routes.
+ */
+
+#ifdef WIN32
+#include "config-win32.h"
+#else
+#include "config.h"
+#endif
+
+#include "syshead.h"
+
+#include "common.h"
+#include "error.h"
+#include "route.h"
+#include "misc.h"
+#include "socket.h"
+#include "manage.h"
+
+#include "memdbg.h"
+
+static void add_route (struct route *r, const struct tuntap *tt, unsigned int flags, const struct env_set *es);
+static void delete_route (const struct route *r, const struct tuntap *tt, unsigned int flags, const struct env_set *es);
+static bool get_default_gateway (in_addr_t *ret);
+
+struct route_option_list *
+new_route_option_list (struct gc_arena *a)
+{
+  struct route_option_list *ret;
+  ALLOC_OBJ_CLEAR_GC (ret, struct route_option_list, a);
+  return ret;
+}
+
+struct route_list *
+new_route_list (struct gc_arena *a)
+{
+  struct route_list *ret;
+  ALLOC_OBJ_CLEAR_GC (ret, struct route_list, a);
+  return ret;
+}
+
+static const char *
+route_string (const struct route *r, struct gc_arena *gc)
+{
+  struct buffer out = alloc_buf_gc (256, gc);
+  buf_printf (&out, "ROUTE network %s netmask %s gateway %s",
+	      print_in_addr_t (r->network, 0, gc),
+	      print_in_addr_t (r->netmask, 0, gc),
+	      print_in_addr_t (r->gateway, 0, gc)
+	      );
+  if (r->metric_defined)
+    buf_printf (&out, " metric %d", r->metric);
+  return BSTR (&out);
+}
+
+static bool
+is_route_parm_defined (const char *parm)
+{
+  if (!parm)
+    return false;
+  if (!strcmp (parm, "default"))
+    return false;
+  return true;
+}
+
+static void
+setenv_route_addr (struct env_set *es, const char *key, const in_addr_t addr, int i)
+{
+  struct gc_arena gc = gc_new ();
+  struct buffer name = alloc_buf_gc (256, &gc);
+  if (i >= 0)
+    buf_printf (&name, "route_%s_%d", key, i);
+  else
+    buf_printf (&name, "route_%s", key);
+  setenv_str (es, BSTR (&name), print_in_addr_t (addr, 0, &gc));
+  gc_free (&gc);
+}
+
+static bool
+get_special_addr (const struct route_special_addr *spec,
+		  const char *string,
+		  in_addr_t *out,
+		  bool *status)
+{
+  *status = true;
+  if (!strcmp (string, "vpn_gateway"))
+    {
+      if (spec->remote_endpoint_defined)
+	*out = spec->remote_endpoint;
+      else
+	{
+	  msg (M_INFO, PACKAGE_NAME " ROUTE: vpn_gateway undefined");
+	  *status = false;
+	}
+      return true;
+    }
+  else if (!strcmp (string, "net_gateway"))
+    {
+      if (spec->net_gateway_defined)
+	*out = spec->net_gateway;
+      else
+	{
+	  msg (M_INFO, PACKAGE_NAME " ROUTE: net_gateway undefined -- unable to get default gateway from system");
+	  *status = false;
+	}
+      return true;
+    }
+  else if (!strcmp (string, "remote_host"))
+    {
+      if (spec->remote_host_defined)
+	*out = spec->remote_host;
+      else
+	{
+	  msg (M_INFO, PACKAGE_NAME " ROUTE: remote_host undefined");
+	  *status = false;
+	}
+      return true;
+    }
+  return false;
+}
+
+static bool
+init_route (struct route *r,
+	    const struct route_option *ro,
+	    const struct route_special_addr *spec)
+{
+  const in_addr_t default_netmask = ~0;
+  bool status;
+
+  r->option = ro;
+  r->defined = false;
+
+  /* network */
+
+  if (!is_route_parm_defined (ro->network))
+    {
+      goto fail;
+    }
+  
+  if (!get_special_addr (spec, ro->network, &r->network, &status))
+    {
+      r->network = getaddr (
+			    GETADDR_RESOLVE
+			    | GETADDR_HOST_ORDER
+			    | GETADDR_WARN_ON_SIGNAL,
+			    ro->network,
+			    0,
+			    &status,
+			    NULL);
+    }
+
+  if (!status)
+    goto fail;
+
+  /* netmask */
+
+  if (is_route_parm_defined (ro->netmask))
+    {
+      r->netmask = getaddr (
+			    GETADDR_HOST_ORDER
+			    | GETADDR_WARN_ON_SIGNAL,
+			    ro->netmask,
+			    0,
+			    &status,
+			    NULL);
+      if (!status)
+	goto fail;
+    }
+  else
+    r->netmask = default_netmask;
+
+  /* gateway */
+
+  if (is_route_parm_defined (ro->gateway))
+    {
+      if (!get_special_addr (spec, ro->gateway, &r->gateway, &status))
+	{
+	  r->gateway = getaddr (
+				GETADDR_RESOLVE
+				| GETADDR_HOST_ORDER
+				| GETADDR_WARN_ON_SIGNAL,
+				ro->gateway,
+				0,
+				&status,
+				NULL);
+	}
+      if (!status)
+	goto fail;
+    }
+  else
+    {
+      if (spec->remote_endpoint_defined)
+	r->gateway = spec->remote_endpoint;
+      else
+	{
+	  msg (M_WARN, PACKAGE_NAME " ROUTE: " PACKAGE_NAME " needs a gateway parameter for a --route option and no default was specified by either --route-gateway or --ifconfig options");
+	  goto fail;
+	}
+    }
+
+  /* metric */
+
+  r->metric_defined = false;
+  r->metric = 0;
+  if (is_route_parm_defined (ro->metric))
+    {
+      r->metric = atoi (ro->metric);
+      if (r->metric < 0)
+	{
+	  msg (M_WARN, PACKAGE_NAME " ROUTE: route metric for network %s (%s) must be >= 0",
+	       ro->network,
+	       ro->metric);
+	  goto fail;
+	}
+      r->metric_defined = true;
+    }
+  else
+    {
+      r->metric = 0;
+      r->metric_defined = false;
+    }
+
+  r->defined = true;
+
+  return true;
+
+ fail:
+  msg (M_WARN, PACKAGE_NAME " ROUTE: failed to parse/resolve route for host/network: %s",
+       ro->network);
+  r->defined = false;
+  return false;
+}
+
+void
+add_route_to_option_list (struct route_option_list *l,
+			  const char *network,
+			  const char *netmask,
+			  const char *gateway,
+			  const char *metric)
+{
+  struct route_option *ro;
+  if (l->n >= MAX_ROUTES)
+    msg (M_FATAL, PACKAGE_NAME " ROUTE: cannot add more than %d routes",
+	 MAX_ROUTES);
+  ro = &l->routes[l->n];
+  ro->network = network;
+  ro->netmask = netmask;
+  ro->gateway = gateway;
+  ro->metric = metric;
+  ++l->n;
+}
+
+void
+clear_route_list (struct route_list *rl)
+{
+  CLEAR (*rl);
+}
+
+bool
+init_route_list (struct route_list *rl,
+		 const struct route_option_list *opt,
+		 const char *remote_endpoint,
+		 in_addr_t remote_host,
+		 struct env_set *es)
+{
+  bool ret = true;
+
+  clear_route_list (rl);
+
+  if (remote_host)
+    {
+      rl->spec.remote_host = remote_host;
+      rl->spec.remote_host_defined = true;
+    }
+
+  rl->spec.net_gateway_defined = get_default_gateway (&rl->spec.net_gateway);
+  if (rl->spec.net_gateway_defined)
+    {
+      setenv_route_addr (es, "net_gateway", rl->spec.net_gateway, -1);
+    }
+  rl->redirect_default_gateway = opt->redirect_default_gateway;
+  rl->redirect_local = opt->redirect_local;
+  rl->redirect_def1 = opt->redirect_def1;
+
+  if (is_route_parm_defined (remote_endpoint))
+    {
+      rl->spec.remote_endpoint = getaddr (
+				     GETADDR_RESOLVE
+				     | GETADDR_HOST_ORDER
+				     | GETADDR_WARN_ON_SIGNAL,
+				     remote_endpoint,
+				     0,
+				     &rl->spec.remote_endpoint_defined,
+				     NULL);
+
+      if (rl->spec.remote_endpoint_defined)
+	{
+	  setenv_route_addr (es, "vpn_gateway", rl->spec.remote_endpoint, -1);
+	}
+      else
+	{
+	  msg (M_WARN, PACKAGE_NAME " ROUTE: failed to parse/resolve default gateway: %s",
+	       remote_endpoint);
+	  ret = false;
+	}
+    }
+  else
+    rl->spec.remote_endpoint_defined = false;
+
+  ASSERT (opt->n >= 0 && opt->n < MAX_ROUTES);
+
+  /* parse the routes from opt to rl */
+  {
+    int i, j = 0;
+    for (i = 0; i < opt->n; ++i)
+      {
+	if (!init_route (&rl->routes[j],
+			 &opt->routes[i],
+			 &rl->spec))
+	  ret = false;
+	else
+	  ++j;
+      }
+    rl->n = j;
+  }
+
+  return ret;
+}
+
+static void
+add_route3 (in_addr_t network,
+	    in_addr_t netmask,
+	    in_addr_t gateway,
+	    const struct tuntap *tt,
+	    unsigned int flags,
+	    const struct env_set *es)
+{
+  struct route r;
+  CLEAR (r);
+  r.defined = true;
+  r.network = network;
+  r.netmask = netmask;
+  r.gateway = gateway;
+  add_route (&r, tt, flags, es);
+}
+
+static void
+del_route3 (in_addr_t network,
+	    in_addr_t netmask,
+	    in_addr_t gateway,
+	    const struct tuntap *tt,
+	    unsigned int flags,
+	    const struct env_set *es)
+{
+  struct route r;
+  CLEAR (r);
+  r.defined = true;
+  r.network = network;
+  r.netmask = netmask;
+  r.gateway = gateway;
+  delete_route (&r, tt, flags, es);
+}
+
+static void
+redirect_default_route_to_vpn (struct route_list *rl, const struct tuntap *tt, unsigned int flags, const struct env_set *es)
+{
+  const char err[] = "NOTE: unable to redirect default gateway --";
+
+  if (rl->redirect_default_gateway)
+    {
+      if (!rl->spec.remote_endpoint_defined)
+	{
+	  msg (M_WARN, "%s VPN gateway parameter (--route-gateway or --ifconfig) is missing", err);
+	}
+      else if (!rl->spec.net_gateway_defined)
+	{
+	  msg (M_WARN, "%s Cannot read current default gateway from system", err);
+	}
+      else if (!rl->spec.remote_host_defined)
+	{
+	  msg (M_WARN, "%s Cannot obtain current remote host address", err);
+	}
+      else
+	{
+	  /* route remote host to original default gateway */
+	  if (!rl->redirect_local)
+	    add_route3 (rl->spec.remote_host,
+			~0,
+			rl->spec.net_gateway,
+			tt,
+			flags,
+			es);
+
+	  if (rl->redirect_def1)
+	    {
+	      /* add new default route (1st component) */
+	      add_route3 (0x00000000,
+			  0x80000000,
+			  rl->spec.remote_endpoint,
+			  tt,
+			  flags,
+			  es);
+
+	      /* add new default route (2nd component) */
+	      add_route3 (0x80000000,
+			  0x80000000,
+			  rl->spec.remote_endpoint,
+			  tt,
+			  flags,
+			  es);
+	    }
+	  else
+	    {
+	      /* delete default route */
+	      del_route3 (0,
+			  0,
+			  rl->spec.net_gateway,
+			  tt,
+			  flags,
+			  es);
+
+	      /* add new default route */
+	      add_route3 (0,
+			  0,
+			  rl->spec.remote_endpoint,
+			  tt,
+			  flags,
+			  es);
+	    }
+
+	  /* set a flag so we can undo later */
+	  rl->did_redirect_default_gateway = true;
+	}
+    }
+}
+
+static void
+undo_redirect_default_route_to_vpn (struct route_list *rl, const struct tuntap *tt, unsigned int flags, const struct env_set *es)
+{
+  if (rl->did_redirect_default_gateway)
+    {
+      /* delete remote host route */
+      if (!rl->redirect_local)
+	del_route3 (rl->spec.remote_host,
+		    ~0,
+		    rl->spec.net_gateway,
+		    tt,
+		    flags,
+		    es);
+
+      if (rl->redirect_def1)
+	{
+	  /* delete default route (1st component) */
+	  del_route3 (0x00000000,
+		      0x80000000,
+		      rl->spec.remote_endpoint,
+		      tt,
+		      flags,
+		      es);
+
+	  /* delete default route (2nd component) */
+	  del_route3 (0x80000000,
+		      0x80000000,
+		      rl->spec.remote_endpoint,
+		      tt,
+		      flags,
+		      es);
+	}
+      else
+	{
+	  /* delete default route */
+	  del_route3 (0,
+		      0,
+		      rl->spec.remote_endpoint,
+		      tt,
+		      flags,
+		      es);
+
+	  /* restore original default route */
+	  add_route3 (0,
+		      0,
+		      rl->spec.net_gateway,
+		      tt,
+		      flags,
+		      es);
+	}
+
+      rl->did_redirect_default_gateway = false;
+    }
+}
+
+void
+add_routes (struct route_list *rl, const struct tuntap *tt, unsigned int flags, const struct env_set *es)
+{
+  redirect_default_route_to_vpn (rl, tt, flags, es);
+  if (!rl->routes_added)
+    {
+      int i;
+
+#ifdef ENABLE_MANAGEMENT
+      if (management && rl->n)
+	{
+	  management_set_state (management,
+				OPENVPN_STATE_ADD_ROUTES,
+				NULL,
+				0);
+	}
+#endif
+      
+      for (i = 0; i < rl->n; ++i)
+	{
+	  if (flags & ROUTE_DELETE_FIRST)
+	    delete_route (&rl->routes[i], tt, flags, es);
+	  add_route (&rl->routes[i], tt, flags, es);
+	}
+      rl->routes_added = true;
+    }
+}
+
+void
+delete_routes (struct route_list *rl, const struct tuntap *tt, unsigned int flags, const struct env_set *es)
+{
+  if (rl->routes_added)
+    {
+      int i;
+      for (i = rl->n - 1; i >= 0; --i)
+	{
+	  const struct route *r = &rl->routes[i];
+	  delete_route (r, tt, flags, es);
+	}
+      rl->routes_added = false;
+    }
+  undo_redirect_default_route_to_vpn (rl, tt, flags, es);
+
+  CLEAR (*rl);
+}
+
+#ifdef ENABLE_DEBUG
+
+static const char *
+show_opt (const char *option)
+{
+  if (!option)
+    return "nil";
+  else
+    return option;
+}
+
+static void
+print_route_option (const struct route_option *ro, int level)
+{
+  msg (level, "  route %s/%s/%s/%s",
+       show_opt (ro->network),
+       show_opt (ro->netmask),
+       show_opt (ro->gateway),
+       show_opt (ro->metric));
+}
+
+void
+print_route_options (const struct route_option_list *rol,
+		     int level)
+{
+  int i;
+  if (rol->redirect_default_gateway)
+    msg (level, "  [redirect_default_gateway local=%d]",
+	 rol->redirect_local);
+  for (i = 0; i < rol->n; ++i)
+    print_route_option (&rol->routes[i], level);
+}
+
+#endif
+
+static void
+print_route (const struct route *r, int level)
+{
+  struct gc_arena gc = gc_new ();
+  if (r->defined)
+    msg (level, "%s", route_string (r, &gc));
+  gc_free (&gc);
+}
+
+void
+print_routes (const struct route_list *rl, int level)
+{
+  int i;
+  for (i = 0; i < rl->n; ++i)
+    print_route (&rl->routes[i], level);
+}
+
+static void
+setenv_route (struct env_set *es, const struct route *r, int i)
+{
+  struct gc_arena gc = gc_new ();
+  if (r->defined)
+    {
+      setenv_route_addr (es, "network", r->network, i);
+      setenv_route_addr (es, "netmask", r->netmask, i);
+      setenv_route_addr (es, "gateway", r->gateway, i);
+
+      if (r->metric_defined)
+	{
+	  struct buffer name = alloc_buf_gc (256, &gc);
+	  buf_printf (&name, "route_metric_%d", i);
+	  setenv_int (es, BSTR (&name), r->metric);
+	}
+    }
+  gc_free (&gc);
+}
+
+void
+setenv_routes (struct env_set *es, const struct route_list *rl)
+{
+  int i;
+  for (i = 0; i < rl->n; ++i)
+    setenv_route (es, &rl->routes[i], i + 1);
+}
+
+static void
+add_route (struct route *r, const struct tuntap *tt, unsigned int flags, const struct env_set *es)
+{
+  struct gc_arena gc;
+  struct buffer buf;
+  const char *network;
+  const char *netmask;
+  const char *gateway;
+  bool status = false;
+
+  if (!r->defined)
+    return;
+
+  gc_init (&gc);
+  buf = alloc_buf_gc (256, &gc);
+
+  network = print_in_addr_t (r->network, 0, &gc);
+  netmask = print_in_addr_t (r->netmask, 0, &gc);
+  gateway = print_in_addr_t (r->gateway, 0, &gc);
+
+  /*
+   * Filter out routes which are essentially no-ops
+   */
+  if (r->network == r->gateway && r->netmask == 0xFFFFFFFF)
+    {
+      msg (M_INFO, PACKAGE_NAME " ROUTE: omitted no-op route: %s/%s -> %s",
+	   network, netmask, gateway);
+      goto done;
+    }
+
+#if defined(TARGET_LINUX)
+#ifdef CONFIG_FEATURE_IPROUTE
+  buf_printf (&buf, IPROUTE_PATH " route add %s/%d via %s",
+	      network,
+	      count_netmask_bits(netmask),
+	      gateway);
+  if (r->metric_defined)
+    buf_printf (&buf, " metric %d", r->metric);
+
+#else
+  buf_printf (&buf, ROUTE_PATH " add -net %s netmask %s gw %s",
+	      network,
+	      netmask,
+	      gateway);
+  if (r->metric_defined)
+    buf_printf (&buf, " metric %d", r->metric);
+#endif  /*CONFIG_FEATURE_IPROUTE*/
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  status = system_check (BSTR (&buf), es, 0, "ERROR: Linux route add command failed");
+
+#elif defined (WIN32)
+
+  buf_printf (&buf, ROUTE_PATH " ADD %s MASK %s %s",
+	      network,
+	      netmask,
+	      gateway);
+  if (r->metric_defined)
+    buf_printf (&buf, " METRIC %d", r->metric);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+
+  if ((flags & ROUTE_METHOD_MASK) == ROUTE_METHOD_IPAPI)
+    {
+      status = add_route_ipapi (r, tt);
+      msg (D_ROUTE, "Route addition via IPAPI %s", status ? "succeeded" : "failed");
+    }
+  else if ((flags & ROUTE_METHOD_MASK) == ROUTE_METHOD_EXE)
+    {
+      netcmd_semaphore_lock ();
+      status = system_check (BSTR (&buf), es, 0, "ERROR: Windows route add command failed");
+      netcmd_semaphore_release ();
+    }
+  else
+    {
+      ASSERT (0);
+    }
+
+#elif defined (TARGET_SOLARIS)
+
+  /* example: route add 192.0.2.32 -netmask 255.255.255.224 somegateway */
+
+  buf_printf (&buf, ROUTE_PATH " add");
+
+#if 0
+  if (r->metric_defined)
+    buf_printf (&buf, " -rtt %d", r->metric);
+#endif
+
+  buf_printf (&buf, " %s -netmask %s %s",
+	      network,
+	      netmask,
+	      gateway);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  status = system_check (BSTR (&buf), es, 0, "ERROR: Solaris route add command failed");
+
+#elif defined(TARGET_FREEBSD)
+
+  buf_printf (&buf, ROUTE_PATH " add");
+
+#if 0
+  if (r->metric_defined)
+    buf_printf (&buf, " -rtt %d", r->metric);
+#endif
+
+  buf_printf (&buf, " -net %s %s %s",
+	      network,
+	      gateway,
+	      netmask);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  status = system_check (BSTR (&buf), es, 0, "ERROR: FreeBSD route add command failed");
+
+#elif defined(TARGET_DARWIN)
+
+  buf_printf (&buf, ROUTE_PATH " add");
+
+#if 0
+  if (r->metric_defined)
+    buf_printf (&buf, " -rtt %d", r->metric);
+#endif
+
+  buf_printf (&buf, " -net %s %s %s",
+              network,
+              gateway,
+              netmask);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  status = system_check (BSTR (&buf), es, 0, "ERROR: OS X route add command failed");
+
+#elif defined(TARGET_OPENBSD) || defined(TARGET_NETBSD)
+
+  buf_printf (&buf, ROUTE_PATH " add");
+
+#if 0
+  if (r->metric_defined)
+    buf_printf (&buf, " -rtt %d", r->metric);
+#endif
+
+  buf_printf (&buf, " -net %s %s -netmask %s",
+	      network,
+	      gateway,
+	      netmask);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  status = system_check (BSTR (&buf), es, 0, "ERROR: OpenBSD/NetBSD route add command failed");
+
+#else
+  msg (M_FATAL, "Sorry, but I don't know how to do 'route' commands on this operating system.  Try putting your routes in a --route-up script");
+#endif
+
+ done:
+  r->defined = status;
+  gc_free (&gc);
+}
+
+static void
+delete_route (const struct route *r, const struct tuntap *tt, unsigned int flags, const struct env_set *es)
+{
+  struct gc_arena gc;
+  struct buffer buf;
+  const char *network;
+  const char *netmask;
+  const char *gateway;
+
+  if (!r->defined)
+    return;
+
+  gc_init (&gc);
+
+  buf = alloc_buf_gc (256, &gc);
+  network = print_in_addr_t (r->network, 0, &gc);
+  netmask = print_in_addr_t (r->netmask, 0, &gc);
+  gateway = print_in_addr_t (r->gateway, 0, &gc);
+
+#if defined(TARGET_LINUX)
+#ifdef CONFIG_FEATURE_IPROUTE
+  buf_printf (&buf, IPROUTE_PATH " route del %s/%d",
+	      network,
+	      count_netmask_bits(netmask));
+#else
+
+  buf_printf (&buf, ROUTE_PATH " del -net %s netmask %s",
+	      network,
+	      netmask);
+#endif /*CONFIG_FEATURE_IPROUTE*/
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  system_check (BSTR (&buf), es, 0, "ERROR: Linux route delete command failed");
+
+#elif defined (WIN32)
+  
+  buf_printf (&buf, ROUTE_PATH " DELETE %s MASK %s %s",
+	      network,
+              netmask,
+              gateway);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+
+  if ((flags & ROUTE_METHOD_MASK) == ROUTE_METHOD_IPAPI)
+    {
+      const bool status = del_route_ipapi (r, tt);
+      msg (D_ROUTE, "Route deletion via IPAPI %s", status ? "succeeded" : "failed");
+    }
+  else if ((flags & ROUTE_METHOD_MASK) == ROUTE_METHOD_EXE)
+    {
+      netcmd_semaphore_lock ();
+      system_check (BSTR (&buf), es, 0, "ERROR: Windows route delete command failed");
+      netcmd_semaphore_release ();
+    }
+  else
+    {
+      ASSERT (0);
+    }
+
+#elif defined (TARGET_SOLARIS)
+
+  buf_printf (&buf, ROUTE_PATH " delete %s -netmask %s %s",
+	      network,
+	      netmask,
+	      gateway);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  system_check (BSTR (&buf), es, 0, "ERROR: Solaris route delete command failed");
+
+#elif defined(TARGET_FREEBSD)
+
+  buf_printf (&buf, ROUTE_PATH " delete -net %s %s %s",
+	      network,
+	      gateway,
+	      netmask);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  system_check (BSTR (&buf), es, 0, "ERROR: FreeBSD route delete command failed");
+
+#elif defined(TARGET_DARWIN)
+
+  buf_printf (&buf, ROUTE_PATH " delete -net %s %s %s",
+              network,
+              gateway,
+              netmask);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  system_check (BSTR (&buf), es, 0, "ERROR: OS X route delete command failed");
+
+#elif defined(TARGET_OPENBSD) || defined(TARGET_NETBSD)
+
+  buf_printf (&buf, ROUTE_PATH " delete -net %s %s -netmask %s",
+	      network,
+	      gateway,
+	      netmask);
+
+  msg (D_ROUTE, "%s", BSTR (&buf));
+  system_check (BSTR (&buf), es, 0, "ERROR: OpenBSD/NetBSD route delete command failed");
+
+#else
+  msg (M_FATAL, "Sorry, but I don't know how to do 'route' commands on this operating system.  Try putting your routes in a --route-up script");
+#endif
+
+  gc_free (&gc);
+}
+
+/*
+ * The --redirect-gateway option requires OS-specific code below
+ * to get the current default gateway.
+ */
+
+#if defined(WIN32)
+
+static const MIB_IPFORWARDTABLE *
+get_windows_routing_table (struct gc_arena *gc)
+{
+  ULONG size = 0;
+  PMIB_IPFORWARDTABLE rt = NULL;
+  DWORD status;
+
+  status = GetIpForwardTable (NULL, &size, TRUE);
+  if (status == ERROR_INSUFFICIENT_BUFFER)
+    {
+      rt = (PMIB_IPFORWARDTABLE) gc_malloc (size, false, gc);
+      status = GetIpForwardTable (rt, &size, TRUE);
+      if (status != NO_ERROR)
+	{
+	  msg (D_ROUTE, "NOTE: GetIpForwardTable returned error: %s (code=%u)",
+	       strerror_win32 (status, gc),
+	       (unsigned int)status);
+	  rt = NULL;
+	}
+    }
+  return rt;
+}
+
+static int
+test_route (const IP_ADAPTER_INFO *adapters,
+	    const in_addr_t gateway,
+	    DWORD *index)
+{
+  int count = 0;
+  DWORD i = adapter_index_of_ip (adapters, gateway, &count);
+  if (index)
+    *index = i;
+  return count;
+}
+
+static void
+test_route_helper (bool *ret,
+		   int *count,
+		   int *good,
+		   int *ambig,
+		   const IP_ADAPTER_INFO *adapters,
+		   const in_addr_t gateway)
+{
+  int c;
+
+  ++*count;
+  c = test_route (adapters, gateway, NULL);
+  if (c == 0)
+    *ret = false;
+  else
+    ++*good;
+  if (c > 1)
+    ++*ambig;
+}
+
+/*
+ * If we tried to add routes now, would we succeed?
+ */
+bool
+test_routes (const struct route_list *rl, const struct tuntap *tt)
+{
+  struct gc_arena gc = gc_new ();
+  const IP_ADAPTER_INFO *adapters = get_adapter_info_list (&gc);
+  bool ret = false;
+  int count = 0;
+  int good = 0;
+  int ambig = 0;
+  bool adapter_up = false;
+
+  if (is_adapter_up (tt, adapters))
+    {
+      ret = true;
+      adapter_up = true;
+
+      if (rl)
+	{
+	  int i;
+	  for (i = 0; i < rl->n; ++i)
+	    test_route_helper (&ret, &count, &good, &ambig, adapters, rl->routes[i].gateway);
+
+	  if (rl->redirect_default_gateway && rl->spec.remote_endpoint_defined)
+	    test_route_helper (&ret, &count, &good, &ambig, adapters, rl->spec.remote_endpoint);
+	}
+    }
+
+  msg (D_ROUTE, "TEST ROUTES: %d/%d succeeded len=%d ret=%d a=%d u/d=%s",
+       good,
+       count,
+       rl ? rl->n : -1,
+       (int)ret,
+       ambig,
+       adapter_up ? "up" : "down");
+
+  gc_free (&gc);
+  return ret;
+}
+
+static bool
+get_default_gateway (in_addr_t *ret)
+{
+  struct gc_arena gc = gc_new ();
+  bool ret_bool = false;
+  int i;
+  const MIB_IPFORWARDTABLE *routes = get_windows_routing_table (&gc);
+
+  if (!routes)
+    goto done;
+
+  for (i = 0; i < routes->dwNumEntries; ++i)
+    {
+      const MIB_IPFORWARDROW *row = &routes->table[i];
+      const in_addr_t net = ntohl (row->dwForwardDest);
+      const in_addr_t mask = ntohl (row->dwForwardMask);
+      const in_addr_t gw = ntohl (row->dwForwardNextHop);
+
+#if 0
+      msg (M_INFO, "route[%d] %s %s %s",
+	   i,
+	   print_in_addr_t ((in_addr_t) net, 0, &gc),
+	   print_in_addr_t ((in_addr_t) mask, 0, &gc),
+	   print_in_addr_t ((in_addr_t) gw, 0, &gc));
+#endif
+      if (!net && !mask)
+	{
+	  *ret = gw;
+	  ret_bool = true;
+	  break;
+	}
+    }
+  
+ done:
+  gc_free (&gc);
+  return ret_bool;
+}
+
+static DWORD
+windows_route_find_if_index (const struct route *r, const struct tuntap *tt)
+{
+  struct gc_arena gc = gc_new ();
+  DWORD ret = ~0;
+  int count = 0;
+  const IP_ADAPTER_INFO *adapters = get_adapter_info_list (&gc);
+  const IP_ADAPTER_INFO *tun_adapter = get_tun_adapter (tt, adapters);
+  bool on_tun = false;
+
+  /* first test on tun interface */
+  if (is_ip_in_adapter_subnet (tun_adapter, r->gateway, NULL))
+    {
+      ret = tun_adapter->Index;
+      count = 1;
+      on_tun = true;
+    }
+  else /* test on other interfaces */
+    {
+      count = test_route (adapters, r->gateway, &ret);
+    }
+
+  if (count == 0)
+    {
+      msg (M_WARN, "Warning: route gateway is not reachable on any active network adapters: %s",
+	   print_in_addr_t (r->gateway, 0, &gc));
+      ret = ~0;
+    }
+  else if (count > 1)
+    {
+      msg (M_WARN, "Warning: route gateway is ambiguous: %s (%d matches)",
+	   print_in_addr_t (r->gateway, 0, &gc),
+	   count);
+      ret = ~0;
+    }
+
+  dmsg (D_ROUTE_DEBUG, "DEBUG: route find if: on_tun=%d count=%d index=%d",
+       on_tun,
+       count,
+       (int)ret);
+
+  gc_free (&gc);
+  return ret;
+}
+
+bool
+add_route_ipapi (const struct route *r, const struct tuntap *tt)
+{
+  struct gc_arena gc = gc_new ();
+  bool ret = false;
+  DWORD status;
+  const DWORD if_index = windows_route_find_if_index (r, tt);  
+
+  if (if_index != ~0)
+    {
+      MIB_IPFORWARDROW fr;
+      CLEAR (fr);
+      fr.dwForwardDest = htonl (r->network);
+      fr.dwForwardMask = htonl (r->netmask);
+      fr.dwForwardPolicy = 0;
+      fr.dwForwardNextHop = htonl (r->gateway);
+      fr.dwForwardIfIndex = if_index;
+      fr.dwForwardType = 4;  /* the next hop is not the final dest */
+      fr.dwForwardProto = 3; /* PROTO_IP_NETMGMT */
+      fr.dwForwardAge = 0;
+      fr.dwForwardNextHopAS = 0;
+      fr.dwForwardMetric1 = r->metric_defined ? r->metric : 1;
+      fr.dwForwardMetric2 = ~0;
+      fr.dwForwardMetric3 = ~0;
+      fr.dwForwardMetric4 = ~0;
+      fr.dwForwardMetric5 = ~0;
+
+      if ((r->network & r->netmask) != r->network)
+	msg (M_WARN, "Warning: address %s is not a network address in relation to netmask %s",
+	     print_in_addr_t (r->network, 0, &gc),
+	     print_in_addr_t (r->netmask, 0, &gc));
+
+      status = CreateIpForwardEntry (&fr);
+
+      if (status == NO_ERROR)
+	ret = true;
+      else
+	{
+	  /* failed, try a different forward type (--redirect-gateway over RRAS seems to need this) */
+	  fr.dwForwardType = 3;  /* the next hop is the final dest */
+
+	  status = CreateIpForwardEntry (&fr);
+
+	  if (status == NO_ERROR)
+	    ret = true;
+	  else
+	    msg (M_WARN, "ROUTE: route addition failed using CreateIpForwardEntry: %s [if_index=%u]",
+		 strerror_win32 (status, &gc),
+		 (unsigned int)if_index);
+	}
+    }
+
+  gc_free (&gc);
+  return ret;
+}
+
+bool
+del_route_ipapi (const struct route *r, const struct tuntap *tt)
+{
+  struct gc_arena gc = gc_new ();
+  bool ret = false;
+  DWORD status;
+  const DWORD if_index = windows_route_find_if_index (r, tt);
+
+  if (if_index != ~0)
+    {
+      MIB_IPFORWARDROW fr;
+      CLEAR (fr);
+
+      fr.dwForwardDest = htonl (r->network);
+      fr.dwForwardMask = htonl (r->netmask);
+      fr.dwForwardPolicy = 0;
+      fr.dwForwardNextHop = htonl (r->gateway);
+      fr.dwForwardIfIndex = if_index;
+
+      status = DeleteIpForwardEntry (&fr);
+
+      if (status == NO_ERROR)
+	ret = true;
+      else
+	msg (M_WARN, "ROUTE: route deletion failed using DeleteIpForwardEntry: %s",
+	     strerror_win32 (status, &gc));
+    }
+
+  gc_free (&gc);
+  return ret;
+}
+
+static const char *
+format_route_entry (const MIB_IPFORWARDROW *r, struct gc_arena *gc)
+{
+  struct buffer out = alloc_buf_gc (256, gc);
+  buf_printf (&out, "%s %s %s p=%d i=%d t=%d pr=%d a=%d h=%d m=%d/%d/%d/%d/%d", 
+	      print_in_addr_t (r->dwForwardDest, IA_NET_ORDER, gc),
+	      print_in_addr_t (r->dwForwardMask, IA_NET_ORDER, gc),
+	      print_in_addr_t (r->dwForwardNextHop, IA_NET_ORDER, gc),
+	      (int)r->dwForwardPolicy,
+	      (int)r->dwForwardIfIndex,
+	      (int)r->dwForwardType,
+	      (int)r->dwForwardProto,
+	      (int)r->dwForwardAge,
+	      (int)r->dwForwardNextHopAS,
+	      (int)r->dwForwardMetric1,
+	      (int)r->dwForwardMetric2,
+	      (int)r->dwForwardMetric3,
+	      (int)r->dwForwardMetric4,
+	      (int)r->dwForwardMetric5);
+  return BSTR (&out);
+}
+
+/*
+ * Show current routing table
+ */
+void
+show_routes (int msglev)
+{
+  struct gc_arena gc = gc_new ();
+  int i;
+
+  const MIB_IPFORWARDTABLE *rt = get_windows_routing_table (&gc);
+
+  msg (msglev, "SYSTEM ROUTING TABLE");
+  if (rt)
+    {
+      for (i = 0; i < rt->dwNumEntries; ++i)
+	{
+	  msg (msglev, "%s", format_route_entry (&rt->table[i], &gc));
+	}
+    }
+  gc_free (&gc);
+}
+
+#elif defined(TARGET_LINUX)
+
+static bool
+get_default_gateway (in_addr_t *ret)
+{
+  struct gc_arena gc = gc_new ();
+  FILE *fp = fopen ("/proc/net/route", "r");
+  if (fp)
+    {
+      char line[256];
+      int count = 0;
+      while (fgets (line, sizeof (line), fp) != NULL)
+	{
+	  if (count)
+	    {
+	      unsigned int net_x = 0;
+	      unsigned int mask_x = 0;
+	      unsigned int gw_x = 0;
+	      const int np = sscanf (line, "%*s\t%x\t%x\t%*s\t%*s\t%*s\t%*s\t%x",
+				     &net_x,
+				     &gw_x,
+				     &mask_x);
+	      if (np == 3)
+		{
+		  const in_addr_t net = ntohl (net_x);
+		  const in_addr_t mask = ntohl (mask_x);
+		  const in_addr_t gw = ntohl (gw_x);
+#if 0
+		  msg (M_INFO, "route %s %s %s",
+		       print_in_addr_t ((in_addr_t) net, 0, &gc),
+		       print_in_addr_t ((in_addr_t) mask, 0, &gc),
+		       print_in_addr_t ((in_addr_t) gw, 0, &gc));
+#endif
+		  if (!net && !mask)
+		    {
+		      fclose (fp);
+		      *ret = gw;
+		      gc_free (&gc);
+		      return true;
+		    }
+		}
+	    }
+	  ++count;
+	}
+      fclose (fp);
+    }
+
+  gc_free (&gc);
+  return false;
+}
+
+#elif defined(TARGET_FREEBSD)
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+/* all of this is taken from <net/route.h> in FreeBSD */
+#define RTA_DST     0x1
+#define RTA_GATEWAY 0x2
+#define RTA_NETMASK 0x4
+
+#define RTM_GET     0x4
+#define RTM_VERSION 5
+
+#define RTF_UP      0x1
+#define RTF_GATEWAY 0x2
+
+/*
+ * These numbers are used by reliable protocols for determining
+ * retransmission behavior and are included in the routing structure.
+ */
+struct rt_metrics {
+        u_long  rmx_locks;      /* Kernel must leave these values alone */
+        u_long  rmx_mtu;        /* MTU for this path */
+        u_long  rmx_hopcount;   /* max hops expected */
+        u_long  rmx_expire;     /* lifetime for route, e.g. redirect */
+        u_long  rmx_recvpipe;   /* inbound delay-bandwidth product */
+        u_long  rmx_sendpipe;   /* outbound delay-bandwidth product */
+        u_long  rmx_ssthresh;   /* outbound gateway buffer limit */
+        u_long  rmx_rtt;        /* estimated round trip time */
+        u_long  rmx_rttvar;     /* estimated rtt variance */
+        u_long  rmx_pksent;     /* packets sent using this route */
+        u_long  rmx_filler[4];  /* will be used for T/TCP later */
+};
+
+/*
+ * Structures for routing messages.
+ */
+struct rt_msghdr {
+        u_short rtm_msglen;     /* to skip over non-understood messages */
+        u_char  rtm_version;    /* future binary compatibility */
+        u_char  rtm_type;       /* message type */
+        u_short rtm_index;      /* index for associated ifp */
+        int     rtm_flags;      /* flags, incl. kern & message, e.g. DONE */
+        int     rtm_addrs;      /* bitmask identifying sockaddrs in msg */
+        pid_t   rtm_pid;        /* identify sender */
+        int     rtm_seq;        /* for sender to identify action */
+        int     rtm_errno;      /* why failed */
+        int     rtm_use;        /* from rtentry */
+        u_long  rtm_inits;      /* which metrics we are initializing */
+        struct  rt_metrics rtm_rmx; /* metrics themselves */
+};
+
+struct {
+  struct rt_msghdr m_rtm;
+  char       m_space[512];
+} m_rtmsg;
+
+#define ROUNDUP(a) \
+        ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
+
+static bool
+get_default_gateway (in_addr_t *ret)
+{
+  struct gc_arena gc = gc_new ();
+  int s, seq, l, pid, rtm_addrs, i;
+  struct sockaddr so_dst, so_mask;
+  char *cp = m_rtmsg.m_space; 
+  struct sockaddr *gate = NULL, *sa;
+  struct  rt_msghdr *rtm_aux;
+
+#define NEXTADDR(w, u) \
+        if (rtm_addrs & (w)) {\
+            l = ROUNDUP(u.sa_len); memmove(cp, &(u), l); cp += l;\
+        }
+
+#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
+
+#define rtm m_rtmsg.m_rtm
+
+  pid = getpid();
+  seq = 0;
+  rtm_addrs = RTA_DST | RTA_NETMASK;
+
+  bzero(&so_dst, sizeof(so_dst));
+  bzero(&so_mask, sizeof(so_mask));
+  bzero(&rtm, sizeof(struct rt_msghdr));
+
+  rtm.rtm_type = RTM_GET;
+  rtm.rtm_flags = RTF_UP | RTF_GATEWAY;
+  rtm.rtm_version = RTM_VERSION;
+  rtm.rtm_seq = ++seq;
+  rtm.rtm_addrs = rtm_addrs; 
+
+  so_dst.sa_family = AF_INET;
+  so_dst.sa_len = sizeof(struct sockaddr_in);
+  so_mask.sa_family = AF_INET;
+  so_mask.sa_len = sizeof(struct sockaddr_in);
+
+  NEXTADDR(RTA_DST, so_dst);
+  NEXTADDR(RTA_NETMASK, so_mask);
+
+  rtm.rtm_msglen = l = cp - (char *)&m_rtmsg;
+
+  s = socket(PF_ROUTE, SOCK_RAW, 0);
+
+  if (write(s, (char *)&m_rtmsg, l) < 0)
+    {
+      warn("writing to routing socket");
+      gc_free (&gc);
+      close(s);
+      return false;
+    }
+
+  do {
+    l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
+  } while (l > 0 && (rtm.rtm_seq != seq || rtm.rtm_pid != pid));
+                        
+  close(s);
+
+  rtm_aux = &rtm;
+
+  cp = ((char *)(rtm_aux + 1));
+  if (rtm_aux->rtm_addrs) {
+    for (i = 1; i; i <<= 1)
+      if (i & rtm_aux->rtm_addrs) {
+	sa = (struct sockaddr *)cp;
+	if (i == RTA_GATEWAY )
+	  gate = sa;
+	ADVANCE(cp, sa);
+      }
+  }
+  else
+    {
+      gc_free (&gc);
+      return false;
+    }
+
+
+  if (gate != NULL )
+    {
+      *ret = ntohl(((struct sockaddr_in *)gate)->sin_addr.s_addr);
+#if 1
+      msg (M_INFO, "gw %s",
+	   print_in_addr_t ((in_addr_t) *ret, 0, &gc));
+#endif
+
+      gc_free (&gc);
+      return true;
+    }
+  else
+    {
+      gc_free (&gc);
+      return false;
+    }
+}
+
+#elif defined(TARGET_DARWIN)
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+/* all of this is taken from <net/route.h> in Darwin */
+#define RTA_DST     0x1
+#define RTA_GATEWAY 0x2
+#define RTA_NETMASK 0x4
+
+#define RTM_GET     0x4
+#define RTM_VERSION 5
+
+#define RTF_UP      0x1
+#define RTF_GATEWAY 0x2
+
+/*
+ * These numbers are used by reliable protocols for determining
+ * retransmission behavior and are included in the routing structure.
+ */
+struct rt_metrics {
+        u_long  rmx_locks;      /* Kernel must leave these values alone */
+        u_long  rmx_mtu;        /* MTU for this path */
+        u_long  rmx_hopcount;   /* max hops expected */
+        u_long  rmx_expire;     /* lifetime for route, e.g. redirect */
+        u_long  rmx_recvpipe;   /* inbound delay-bandwidth product */
+        u_long  rmx_sendpipe;   /* outbound delay-bandwidth product */
+        u_long  rmx_ssthresh;   /* outbound gateway buffer limit */
+        u_long  rmx_rtt;        /* estimated round trip time */
+        u_long  rmx_rttvar;     /* estimated rtt variance */
+        u_long  rmx_pksent;     /* packets sent using this route */
+        u_long  rmx_filler[4];  /* will be used for T/TCP later */
+};
+
+/*
+ * Structures for routing messages.
+ */
+struct rt_msghdr {
+        u_short rtm_msglen;     /* to skip over non-understood messages */
+        u_char  rtm_version;    /* future binary compatibility */
+        u_char  rtm_type;       /* message type */
+        u_short rtm_index;      /* index for associated ifp */
+        int     rtm_flags;      /* flags, incl. kern & message, e.g. DONE */
+        int     rtm_addrs;      /* bitmask identifying sockaddrs in msg */
+        pid_t   rtm_pid;        /* identify sender */
+        int     rtm_seq;        /* for sender to identify action */
+        int     rtm_errno;      /* why failed */
+        int     rtm_use;        /* from rtentry */
+        u_long  rtm_inits;      /* which metrics we are initializing */
+        struct  rt_metrics rtm_rmx; /* metrics themselves */
+};
+
+struct {
+  struct rt_msghdr m_rtm;
+  char       m_space[512];
+} m_rtmsg;
+
+#define ROUNDUP(a) \
+        ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
+
+static bool
+get_default_gateway (in_addr_t *ret)
+{
+  struct gc_arena gc = gc_new ();
+  int s, seq, l, pid, rtm_addrs, i;
+  struct sockaddr so_dst, so_mask;
+  char *cp = m_rtmsg.m_space; 
+  struct sockaddr *gate = NULL, *sa;
+  struct  rt_msghdr *rtm_aux;
+
+#define NEXTADDR(w, u) \
+        if (rtm_addrs & (w)) {\
+            l = ROUNDUP(u.sa_len); memmove(cp, &(u), l); cp += l;\
+        }
+
+#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
+
+#define rtm m_rtmsg.m_rtm
+
+  pid = getpid();
+  seq = 0;
+  rtm_addrs = RTA_DST | RTA_NETMASK;
+
+  bzero(&so_dst, sizeof(so_dst));
+  bzero(&so_mask, sizeof(so_mask));
+  bzero(&rtm, sizeof(struct rt_msghdr));
+
+  rtm.rtm_type = RTM_GET;
+  rtm.rtm_flags = RTF_UP | RTF_GATEWAY;
+  rtm.rtm_version = RTM_VERSION;
+  rtm.rtm_seq = ++seq;
+  rtm.rtm_addrs = rtm_addrs; 
+
+  so_dst.sa_family = AF_INET;
+  so_dst.sa_len = sizeof(struct sockaddr_in);
+  so_mask.sa_family = AF_INET;
+  so_mask.sa_len = sizeof(struct sockaddr_in);
+
+  NEXTADDR(RTA_DST, so_dst);
+  NEXTADDR(RTA_NETMASK, so_mask);
+
+  rtm.rtm_msglen = l = cp - (char *)&m_rtmsg;
+
+  s = socket(PF_ROUTE, SOCK_RAW, 0);
+
+  if (write(s, (char *)&m_rtmsg, l) < 0)
+    {
+      msg (M_WARN, "ROUTE: problem writing to routing socket");
+      gc_free (&gc);
+      close(s);
+      return false;
+    }
+
+  do {
+    l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
+  } while (l > 0 && (rtm.rtm_seq != seq || rtm.rtm_pid != pid));
+                        
+  close(s);
+
+  rtm_aux = &rtm;
+
+  cp = ((char *)(rtm_aux + 1));
+  if (rtm_aux->rtm_addrs) {
+    for (i = 1; i; i <<= 1)
+      if (i & rtm_aux->rtm_addrs) {
+	sa = (struct sockaddr *)cp;
+	if (i == RTA_GATEWAY )
+	  gate = sa;
+	ADVANCE(cp, sa);
+      }
+  }
+  else
+    {
+      gc_free (&gc);
+      return false;
+    }
+
+
+  if (gate != NULL )
+    {
+      *ret = ntohl(((struct sockaddr_in *)gate)->sin_addr.s_addr);
+#if 1
+      msg (M_INFO, "gw %s",
+	   print_in_addr_t ((in_addr_t) *ret, 0, &gc));
+#endif
+
+      gc_free (&gc);
+      return true;
+    }
+  else
+    {
+      gc_free (&gc);
+      return false;
+    }
+}
+
+#elif defined(TARGET_OPENBSD) || defined(TARGET_NETBSD)
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+/* all of this is taken from <net/route.h> in OpenBSD 3.6 */
+#define RTA_DST		0x1	/* destination sockaddr present */
+#define RTA_GATEWAY	0x2	/* gateway sockaddr present */
+#define RTA_NETMASK	0x4	/* netmask sockaddr present */
+
+#define RTM_GET		0x4	/* Report Metrics */
+
+#define RTM_VERSION	3	/* Up the ante and ignore older versions */
+
+#define	RTF_UP		0x1		/* route usable */
+#define	RTF_GATEWAY	0x2		/* destination is a gateway */
+
+/*
+ * Huge version for userland compatibility.
+ */
+struct rt_metrics {
+	u_long	rmx_locks;	/* Kernel must leave these values alone */
+	u_long	rmx_mtu;	/* MTU for this path */
+	u_long	rmx_hopcount;	/* max hops expected */
+	u_long	rmx_expire;	/* lifetime for route, e.g. redirect */
+	u_long	rmx_recvpipe;	/* inbound delay-bandwidth product */
+	u_long	rmx_sendpipe;	/* outbound delay-bandwidth product */
+	u_long	rmx_ssthresh;	/* outbound gateway buffer limit */
+	u_long	rmx_rtt;	/* estimated round trip time */
+	u_long	rmx_rttvar;	/* estimated rtt variance */
+	u_long	rmx_pksent;	/* packets sent using this route */
+};
+
+/*
+ * Structures for routing messages.
+ */
+struct rt_msghdr {
+	u_short	rtm_msglen;	/* to skip over non-understood messages */
+	u_char	rtm_version;	/* future binary compatibility */
+	u_char	rtm_type;	/* message type */
+	u_short	rtm_index;	/* index for associated ifp */
+	int	rtm_flags;	/* flags, incl. kern & message, e.g. DONE */
+	int	rtm_addrs;	/* bitmask identifying sockaddrs in msg */
+	pid_t	rtm_pid;	/* identify sender */
+	int	rtm_seq;	/* for sender to identify action */
+	int	rtm_errno;	/* why failed */
+	int	rtm_use;	/* from rtentry */
+	u_long	rtm_inits;	/* which metrics we are initializing */
+	struct	rt_metrics rtm_rmx; /* metrics themselves */
+};
+
+struct {
+  struct rt_msghdr m_rtm;
+  char       m_space[512];
+} m_rtmsg;
+
+#define ROUNDUP(a) \
+        ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
+
+static bool
+get_default_gateway (in_addr_t *ret)
+{
+  struct gc_arena gc = gc_new ();
+  int s, seq, l, rtm_addrs, i;
+  pid_t pid;
+  struct sockaddr so_dst, so_mask;
+  char *cp = m_rtmsg.m_space; 
+  struct sockaddr *gate = NULL, *sa;
+  struct  rt_msghdr *rtm_aux;
+
+#define NEXTADDR(w, u) \
+        if (rtm_addrs & (w)) {\
+            l = ROUNDUP(u.sa_len); memmove(cp, &(u), l); cp += l;\
+        }
+
+#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
+
+#define rtm m_rtmsg.m_rtm
+
+  pid = getpid();
+  seq = 0;
+  rtm_addrs = RTA_DST | RTA_NETMASK;
+
+  bzero(&so_dst, sizeof(so_dst));
+  bzero(&so_mask, sizeof(so_mask));
+  bzero(&rtm, sizeof(struct rt_msghdr));
+
+  rtm.rtm_type = RTM_GET;
+  rtm.rtm_flags = RTF_UP | RTF_GATEWAY;
+  rtm.rtm_version = RTM_VERSION;
+  rtm.rtm_seq = ++seq;
+  rtm.rtm_addrs = rtm_addrs; 
+
+  so_dst.sa_family = AF_INET;
+  so_dst.sa_len = sizeof(struct sockaddr_in);
+  so_mask.sa_family = AF_INET;
+  so_mask.sa_len = sizeof(struct sockaddr_in);
+
+  NEXTADDR(RTA_DST, so_dst);
+  NEXTADDR(RTA_NETMASK, so_mask);
+
+  rtm.rtm_msglen = l = cp - (char *)&m_rtmsg;
+
+  s = socket(PF_ROUTE, SOCK_RAW, 0);
+
+  if (write(s, (char *)&m_rtmsg, l) < 0)
+    {
+      warn("writing to routing socket");
+      gc_free (&gc);
+      close(s);
+      return false;
+    }
+
+  do {
+    l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
+  } while (l > 0 && (rtm.rtm_seq != seq || rtm.rtm_pid != pid));
+                        
+  close(s);
+
+  rtm_aux = &rtm;
+
+  cp = ((char *)(rtm_aux + 1));
+  if (rtm_aux->rtm_addrs) {
+    for (i = 1; i; i <<= 1)
+      if (i & rtm_aux->rtm_addrs) {
+	sa = (struct sockaddr *)cp;
+	if (i == RTA_GATEWAY )
+	  gate = sa;
+	ADVANCE(cp, sa);
+      }
+  }
+  else
+    {
+      gc_free (&gc);
+      return false;
+    }
+
+
+  if (gate != NULL )
+    {
+      *ret = ntohl(((struct sockaddr_in *)gate)->sin_addr.s_addr);
+#if 1
+      msg (M_INFO, "gw %s",
+	   print_in_addr_t ((in_addr_t) *ret, 0, &gc));
+#endif
+
+      gc_free (&gc);
+      return true;
+    }
+  else
+    {
+      gc_free (&gc);
+      return false;
+    }
+}
+
+#else
+
+static bool
+get_default_gateway (in_addr_t *ret)
+{
+  return false;
+}
+
+#endif
+
+bool
+netmask_to_netbits (const in_addr_t network, const in_addr_t netmask, int *netbits)
+{
+  int i;
+  const int addrlen = sizeof (in_addr_t) * 8;
+
+  if ((network & netmask) == network)
+    {
+      for (i = 0; i <= addrlen; ++i)
+	{
+	  in_addr_t mask = netbits_to_netmask (i);
+	  if (mask == netmask)
+	    {
+	      if (i == addrlen)
+		*netbits = -1;
+	      else
+		*netbits = i;
+	      return true;
+	    }
+	}
+    }
+  return false;
+}