From 5c30df12ae98c0289cdfb2a24aefba2a9d2cc52e Mon Sep 17 00:00:00 2001
From: james <james@e7ae566f-a301-0410-adde-c780ea21d3b5>
Date: Thu, 19 Nov 2009 16:42:51 +0000
Subject: Fixed a client-side bug that occurred when the "dhcp-pre-release" or
 "dhcp-renew" options were combined with "route-gateway dhcp".

The problem is that the IP Helper functions for DHCP release and
renew are blocking, and so calling them from a single-threaded
client stops tunnel traffic forwarding, and hence breaks
"route-gateway dhcp" which requires an active tunnel.  The fix is
to call the IP Helper functions for DHCP release and renew from
another process.

Version 2.1_rc21b.


git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@5164 e7ae566f-a301-0410-adde-c780ea21d3b5
---
 tun.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 67 insertions(+), 29 deletions(-)

(limited to 'tun.c')

diff --git a/tun.c b/tun.c
index 29278b8..d82ac49 100644
--- a/tun.c
+++ b/tun.c
@@ -3292,59 +3292,73 @@ tap_allow_nonadmin_access (const char *dev_node)
 /*
  * DHCP release/renewal
  */
-
 bool
-dhcp_release (const struct tuntap *tt)
+dhcp_release_by_adapter_index(const DWORD adapter_index)
 {
   struct gc_arena gc = gc_new ();
   bool ret = false;
-  if (tt && tt->options.ip_win32_type == IPW32_SET_DHCP_MASQ && tt->adapter_index != ~0)
+  const IP_ADAPTER_INDEX_MAP *inter = get_interface_info (adapter_index, &gc);
+
+  if (inter)
     {
-      const IP_ADAPTER_INDEX_MAP *inter = get_interface_info (tt->adapter_index, &gc);
-      if (inter)
+      DWORD status = IpReleaseAddress ((IP_ADAPTER_INDEX_MAP *)inter);
+      if (status == NO_ERROR)
 	{
-	  DWORD status = IpReleaseAddress ((IP_ADAPTER_INDEX_MAP *)inter);
-	  if (status == NO_ERROR)
-	    {
-	      msg (D_TUNTAP_INFO, "TAP: DHCP address released");
-	      ret = true;
-	    }
-	  else
-	    msg (M_WARN, "NOTE: Release of DHCP-assigned IP address lease on TAP-Win32 adapter failed: %s (code=%u)",
-		 strerror_win32 (status, &gc),
-		 (unsigned int)status);
+	  msg (D_TUNTAP_INFO, "TAP: DHCP address released");
+	  ret = true;
 	}
+      else
+	msg (M_WARN, "NOTE: Release of DHCP-assigned IP address lease on TAP-Win32 adapter failed: %s (code=%u)",
+	     strerror_win32 (status, &gc),
+	     (unsigned int)status);
     }
+
   gc_free (&gc);
   return ret;
 }
 
+static bool
+dhcp_release (const struct tuntap *tt)
+{
+  if (tt && tt->options.ip_win32_type == IPW32_SET_DHCP_MASQ && tt->adapter_index != ~0)
+    return dhcp_release_by_adapter_index (tt->adapter_index);
+  else
+    return false;
+}
+
 bool
-dhcp_renew (const struct tuntap *tt)
+dhcp_renew_by_adapter_index (const DWORD adapter_index)
 {
   struct gc_arena gc = gc_new ();
   bool ret = false;
-  if (tt && tt->options.ip_win32_type == IPW32_SET_DHCP_MASQ && tt->adapter_index != ~0)
+  const IP_ADAPTER_INDEX_MAP *inter = get_interface_info (adapter_index, &gc);
+
+  if (inter)
     {
-      const IP_ADAPTER_INDEX_MAP *inter = get_interface_info (tt->adapter_index, &gc);
-      if (inter)
+      DWORD status = IpRenewAddress ((IP_ADAPTER_INDEX_MAP *)inter);
+      if (status == NO_ERROR)
 	{
-	  DWORD status = IpRenewAddress ((IP_ADAPTER_INDEX_MAP *)inter);
-	  if (status == NO_ERROR)
-	    {
-	      msg (D_TUNTAP_INFO, "TAP: DHCP address renewal succeeded");
-	      ret = true;
-	    }
-	  else
-	    msg (M_WARN, "WARNING: Failed to renew DHCP IP address lease on TAP-Win32 adapter: %s (code=%u)",
-		 strerror_win32 (status, &gc),
-		 (unsigned int)status);
+	  msg (D_TUNTAP_INFO, "TAP: DHCP address renewal succeeded");
+	  ret = true;
 	}
+      else
+	msg (M_WARN, "WARNING: Failed to renew DHCP IP address lease on TAP-Win32 adapter: %s (code=%u)",
+	     strerror_win32 (status, &gc),
+	     (unsigned int)status);
     }
   gc_free (&gc);
   return ret;
 }
 
+static bool
+dhcp_renew (const struct tuntap *tt)
+{
+  if (tt && tt->options.ip_win32_type == IPW32_SET_DHCP_MASQ && tt->adapter_index != ~0)
+    return dhcp_renew_by_adapter_index (tt->adapter_index);
+  else
+    return false;
+}
+
 /*
  * netsh functions
  */
@@ -3788,6 +3802,28 @@ build_dhcp_options_string (struct buffer *buf, const struct tuntap_options *o)
   return !error;
 }
 
+static void
+fork_dhcp_action (struct tuntap *tt)
+{
+  if (tt->options.dhcp_pre_release || tt->options.dhcp_renew)
+    {
+      struct gc_arena gc = gc_new ();
+      struct buffer cmd = alloc_buf_gc (256, &gc);
+      const int verb = 3;
+      const int pre_sleep = 1;
+  
+      buf_printf (&cmd, "openvpn --verb %d --tap-sleep %d", verb, pre_sleep);
+      if (tt->options.dhcp_pre_release)
+	buf_printf (&cmd, " --dhcp-pre-release");
+      if (tt->options.dhcp_renew)
+	buf_printf (&cmd, " --dhcp-renew");
+      buf_printf (&cmd, " --dhcp-rr %u", (unsigned int)tt->adapter_index);
+
+      fork_to_self (BSTR (&cmd));
+      gc_free (&gc);
+    }
+}
+
 void
 open_tun (const char *dev, const char *dev_type, const char *dev_node, bool ipv6, struct tuntap *tt)
 {
@@ -4152,6 +4188,8 @@ open_tun (const char *dev, const char *dev_type, const char *dev_node, bool ipv6
 	if (tt->options.dhcp_renew)
 	  dhcp_renew (tt);
       }
+    else
+      fork_dhcp_action (tt);
 
     if (tt->did_ifconfig_setup && tt->options.ip_win32_type == IPW32_SET_IPAPI)
       {
-- 
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