#45: Use IpHelper to get DNS server on win32

CHANGELOG

@@ -12,6 +12,7 @@ CHANGES:
 	- Added syslog logging for iodined on version and login packets
 	- Fixed segfault when encoding just one block, fixes #51.
 		The normal code was never affected by this.
+	- Added win32 code to read DNS server from system, fixes #45.
 
 2009-01-23: 0.5.0 "iPassed"
 	- Fixed segfault in server when sending version reject.

README-win32.txt

@@ -49,7 +49,6 @@ cross-compile.
 == Results of crappy Win32 API:
 The following fixable limitations apply:
 - The password is shown when entered
-- DNS server IP can not be fetched automatically
 - Exactly one TAP32 interface must be installed
 - The TAP32 interface must be named "dns" and be version 0801
 - Server cannot read packet destination address

src/iodine.c

@@ -890,8 +890,9 @@ static char *
 get_resolvconf_addr()
 {
 	static char addr[16];
-	char buf[80];
 	char *rv;
+#ifndef WINDOWS32
+	char buf[80];
 	FILE *fp;
 	
 	rv = NULL;
@@ -909,7 +910,26 @@ get_resolvconf_addr()
 	}
 	
 	fclose(fp);
+#else /* !WINDOWS32 */
+	FIXED_INFO  *fixed_info;
+	ULONG       buflen;
+	DWORD       ret;
 
+	rv = NULL;
+	fixed_info = malloc(sizeof(FIXED_INFO));
+	buflen = sizeof(FIXED_INFO);
+
+	if (GetNetworkParams(fixed_info, &buflen) == ERROR_BUFFER_OVERFLOW) {
+		/* official ugly api workaround */
+		free(fixed_info);
+		fixed_info = malloc(buflen);
+	}
+
+	ret = GetNetworkParams(fixed_info, &buflen);
+	if (ret == NO_ERROR) {
+		rv = fixed_info->DnsServerList.IpAddress.String;
+	}
+#endif
 	return rv;
 }
 

src/osflags

@@ -14,7 +14,7 @@ link)
 			echo '-lnetwork';
 		;;
 		windows32)
-			echo '-lws2_32';
+			echo '-lws2_32 -liphlpapi';
 		;;
 	esac
 	;;

src/windows.h

@@ -22,6 +22,7 @@ typedef unsigned int in_addr_t;
 #include <windows.h>
 #include <windns.h>
 #include <winsock2.h>
+#include <iphlpapi.h>
 
 #define T_A DNS_TYPE_A
 #define T_NS DNS_TYPE_NS