Added additional warnings to flag common gotchas:

* Warn when ethernet bridging that the IP address of the
  bridge adapter is probably not the same address that
  the LAN adapter was set to previously.

* When running as a server, warn if the LAN network address is
  the all-popular 192.168.[0|1].x, since this condition commonly
  leads to subnet conflicts down the road.

* Primarily on the client, check for subnet conflicts between
  the local LAN and the VPN subnet.

Added a 'netmask' parameter to get_default_gateway, to return
the netmask of the adapter containing the default gateway.
Only implemented on Windows so far.  Other platforms will
return 255.255.255.0.  Currently the netmask information is
only used to warn about subnet conflicts.


git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@3179 e7ae566f-a301-0410-adde-c780ea21d3b5

1 files changed, 51 insertions, 25 deletions

diff --git a/route.c b/route.c
index b968442..d3d4385 100644
--- a/route.c
+++ b/route.c
@@ -39,7 +39,6 @@
 #include "memdbg.h"
 
 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);
 static void get_bypass_addresses (struct route_bypass *rb, const unsigned int flags);
 
 #ifdef ENABLE_DEBUG
@@ -372,11 +371,11 @@ init_route_list (struct route_list *rl,
       rl->spec.default_metric_defined = true;
     }
 
-  rl->spec.net_gateway_defined = get_default_gateway (&rl->spec.net_gateway);
+  rl->spec.net_gateway_defined = get_default_gateway (&rl->spec.net_gateway, NULL);
   if (rl->spec.net_gateway_defined)
     {
       setenv_route_addr (es, "net_gateway", rl->spec.net_gateway, -1);
-      dmsg (D_ROUTE_DEBUG, "ROUTE DEBUG: default_gateway=%s", print_in_addr_t (rl->spec.net_gateway, 0, &gc));
+      dmsg (D_ROUTE, "ROUTE default_gateway=%s", print_in_addr_t (rl->spec.net_gateway, 0, &gc));
     }
   else
     {
@@ -666,9 +665,11 @@ add_routes (struct route_list *rl, const struct tuntap *tt, unsigned int flags,
       
       for (i = 0; i < rl->n; ++i)
 	{
+	  struct route *r = &rl->routes[i];
+	  check_subnet_conflict (r->network, r->netmask, "route");
 	  if (flags & ROUTE_DELETE_FIRST)
-	    delete_route (&rl->routes[i], tt, flags, es);
-	  add_route (&rl->routes[i], tt, flags, es);
+	    delete_route (r, tt, flags, es);
+	  add_route (r, tt, flags, es);
 	}
       rl->routes_added = true;
     }
@@ -1142,7 +1143,7 @@ test_route (const IP_ADAPTER_INFO *adapters,
 	    DWORD *index)
 {
   int count = 0;
-  DWORD i = adapter_index_of_ip (adapters, gateway, &count);
+  DWORD i = adapter_index_of_ip (adapters, gateway, &count, NULL);
   if (index)
     *index = i;
   return count;
@@ -1251,18 +1252,24 @@ get_default_gateway_row (const MIB_IPFORWARDTABLE *routes)
   return ret;
 }
 
-static bool
-get_default_gateway (in_addr_t *ret)
+bool
+get_default_gateway (in_addr_t *gw, in_addr_t *netmask)
 {
   struct gc_arena gc = gc_new ();
   bool ret_bool = false;
 
+  const IP_ADAPTER_INFO *adapters = get_adapter_info_list (&gc);
   const MIB_IPFORWARDTABLE *routes = get_windows_routing_table (&gc);
   const MIB_IPFORWARDROW *row = get_default_gateway_row (routes);
 
   if (row)
     {
-      *ret = ntohl (row->dwForwardNextHop);
+      *gw = ntohl (row->dwForwardNextHop);
+      if (netmask)
+	{
+	  if (adapter_index_of_ip (adapters, *gw, NULL, netmask) == ~0)
+	    *netmask = ~0;
+	}
       ret_bool = true;
     }
 
@@ -1467,8 +1474,8 @@ show_routes (int msglev)
 
 #elif defined(TARGET_LINUX)
 
-static bool
-get_default_gateway (in_addr_t *gateway)
+bool
+get_default_gateway (in_addr_t *gateway, in_addr_t *netmask)
 {
   struct gc_arena gc = gc_new ();
   bool ret = false;
@@ -1521,6 +1528,10 @@ get_default_gateway (in_addr_t *gateway)
       if (best_gw)
 	{
 	  *gateway = best_gw;
+	  if (netmask)
+	    {
+	      *netmask = 0xFFFFFF00; // FIXME -- get the real netmask of the adapter containing the default gateway
+	    }
 	  ret = true;
 	}
 
@@ -1595,8 +1606,8 @@ struct {
 #define ROUNDUP(a) \
         ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
 
-static bool
-get_default_gateway (in_addr_t *ret)
+bool
+get_default_gateway (in_addr_t *ret, in_addr_t *netmask)
 {
   struct gc_arena gc = gc_new ();
   int s, seq, l, pid, rtm_addrs, i;
@@ -1676,11 +1687,16 @@ get_default_gateway (in_addr_t *ret)
   if (gate != NULL )
     {
       *ret = ntohl(((struct sockaddr_in *)gate)->sin_addr.s_addr);
-#if 1
+#if 0
       msg (M_INFO, "gw %s",
 	   print_in_addr_t ((in_addr_t) *ret, 0, &gc));
 #endif
 
+      if (netmask)
+	{
+	  *netmask = 0xFFFFFF00; // FIXME -- get the real netmask of the adapter containing the default gateway
+	}
+
       gc_free (&gc);
       return true;
     }
@@ -1752,8 +1768,8 @@ struct {
 #define ROUNDUP(a) \
         ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
 
-static bool
-get_default_gateway (in_addr_t *ret)
+bool
+get_default_gateway (in_addr_t *ret, in_addr_t *netmask)
 {
   struct gc_arena gc = gc_new ();
   int s, seq, l, pid, rtm_addrs, i;
@@ -1833,11 +1849,16 @@ get_default_gateway (in_addr_t *ret)
   if (gate != NULL )
     {
       *ret = ntohl(((struct sockaddr_in *)gate)->sin_addr.s_addr);
-#if 1
+#if 0
       msg (M_INFO, "gw %s",
 	   print_in_addr_t ((in_addr_t) *ret, 0, &gc));
 #endif
 
+      if (netmask)
+	{
+	  *netmask = 0xFFFFFF00; // FIXME -- get the real netmask of the adapter containing the default gateway
+	}
+
       gc_free (&gc);
       return true;
     }
@@ -1908,8 +1929,8 @@ struct {
 #define ROUNDUP(a) \
         ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
 
-static bool
-get_default_gateway (in_addr_t *ret)
+bool
+get_default_gateway (in_addr_t *ret, in_addr_t *netmask)
 {
   struct gc_arena gc = gc_new ();
   int s, seq, l, rtm_addrs, i;
@@ -1990,11 +2011,16 @@ get_default_gateway (in_addr_t *ret)
   if (gate != NULL )
     {
       *ret = ntohl(((struct sockaddr_in *)gate)->sin_addr.s_addr);
-#if 1
+#if 0
       msg (M_INFO, "gw %s",
 	   print_in_addr_t ((in_addr_t) *ret, 0, &gc));
 #endif
 
+      if (netmask)
+	{
+	  *netmask = 0xFFFFFF00; // FIXME -- get the real netmask of the adapter containing the default gateway
+	}
+
       gc_free (&gc);
       return true;
     }
@@ -2007,8 +2033,8 @@ get_default_gateway (in_addr_t *ret)
 
 #else
 
-static bool
-get_default_gateway (in_addr_t *ret)
+bool
+get_default_gateway (in_addr_t *ret, in_addr_t *netmask)
 {
   return false;
 }
@@ -2126,7 +2152,7 @@ get_default_gateway_mac_addr (unsigned char *macaddr)
   in_addr_t gwip = 0;
   bool ret = false;
 
-  if (!get_default_gateway (&gwip))
+  if (!get_default_gateway (&gwip, NULL))
     {
       msg (M_WARN, "GDGMA: get_default_gateway failed");
       goto err;
@@ -2223,13 +2249,13 @@ get_default_gateway_mac_addr (unsigned char *macaddr)
   DWORD a_index;
   const IP_ADAPTER_INFO *ai;
 
-  if (!get_default_gateway (&gwip))
+  if (!get_default_gateway (&gwip, NULL))
     {
       msg (M_WARN, "GDGMA: get_default_gateway failed");
       goto err;
     }
 
-  a_index = adapter_index_of_ip (adapters, gwip, NULL);
+  a_index = adapter_index_of_ip (adapters, gwip, NULL, NULL);
   ai = get_adapter (adapters, a_index);
 
   if (!ai)