From 8299bd4191a67994451476f45e4ccdac06553274 Mon Sep 17 00:00:00 2001
From: Andy Green <andy@warmcat.com>
Date: Thu, 16 Apr 2020 18:49:15 +0100
Subject: [PATCH] windows: async dns find DNS server using modern api

---
 lib/plat/windows/windows-resolv.c | 51 +++++++++----------------------
 1 file changed, 14 insertions(+), 37 deletions(-)

diff --git a/lib/plat/windows/windows-resolv.c b/lib/plat/windows/windows-resolv.c
index 541cc0ae6..146db2c41 100644
--- a/lib/plat/windows/windows-resolv.c
+++ b/lib/plat/windows/windows-resolv.c
@@ -1,16 +1,4 @@
 /*
- * Adapted from tadns 1.1, from http://adns.sourceforge.net/
- * Original license -->
- *
- * Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
- *
- * "THE BEER-WARE LICENSE" (Revision 42):
- * Sergey Lyubka wrote this file.  As long as you retain this notice you
- * can do whatever you want with this stuff. If we meet some day, and you think
- * this stuff is worth it, you can buy me a beer in return.
- *
- * Integrated into lws, largely rewritten and relicensed (as allowed above)
- *
  * libwebsockets - small server side websockets and web server implementation
  *
  * Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
@@ -35,39 +23,28 @@
  */
 
 #include "private-lib-core.h"
+#include <iphlpapi.h>
 
 lws_async_dns_server_check_t
 lws_plat_asyncdns_init(struct lws_context *context, lws_sockaddr46 *sa46)
 {
-	char	subkey[512], value[128], *key =
-	"SYSTEM\\ControlSet001\\Services\\Tcpip\\Parameters\\Interfaces";
-	HKEY	hKey, hSub;
-	LONG	err;
-	int	i, n;
+	unsigned long ul;
+	FIXED_INFO fi;
+	int n;
 
-	if ((err = RegOpenKey(HKEY_LOCAL_MACHINE, key, &hKey)) != ERROR_SUCCESS) {
-		lwsl_err("%s: cannot open reg key %s: %d\n", __func__, key, err);
+	ul = sizeof(fi);
+	if (GetNetworkParams(&fi, &ul) != NO_ERROR) {
+		lwsl_err("%s: can't get dns servers\n", __func__);
 
-		return 1;
+		return LADNS_CONF_SERVER_UNKNOWN;
 	}
 
-	for (i = 0; RegEnumKey(hKey, i, subkey, sizeof(subkey)) == ERROR_SUCCESS; i++) {
-		DWORD type, len = sizeof(value);
+	lwsl_info("%s: trying %s\n", __func__,
+			fi.DnsServerList.IpAddress.String);
+	n = lws_sa46_parse_numeric_address(
+			fi.DnsServerList.IpAddress.String, sa46);
 
-		if (RegOpenKey(hKey, subkey, &hSub) == ERROR_SUCCESS &&
-		    (RegQueryValueEx(hSub, "NameServer", 0,
-		    &type, value, &len) == ERROR_SUCCESS ||
-		    RegQueryValueEx(hSub, "DhcpNameServer", 0,
-		    &type, value, &len) == ERROR_SUCCESS)) {
-			n = lws_sa46_parse_numeric_address(value, sa46);
-			RegCloseKey(hSub);
-			RegCloseKey(hKey);
-			return n == 0 ? LADNS_CONF_SERVER_CHANGED :
-					LADNS_CONF_SERVER_UNKNOWN;
-		}
-	}
-	RegCloseKey(hKey);
-
-	return LADNS_CONF_SERVER_UNKNOWN;
+	return n == 0 ? LADNS_CONF_SERVER_CHANGED :
+			LADNS_CONF_SERVER_UNKNOWN;
 }