DNS (Windows): add support

Currently reports IPv4 addrs only

CMakeLists.txt

@@ -689,7 +689,7 @@ elseif(WIN32)
         src/detection/physicaldisk/physicaldisk_windows.c
         src/detection/diskio/diskio_windows.c
         src/detection/displayserver/displayserver_windows.c
-        src/detection/dns/dns_linux.c
+        src/detection/dns/dns_windows.c
         src/detection/font/font_windows.c
         src/detection/gpu/gpu_windows.c
         src/detection/host/host_windows.c

src/detection/dns/dns_nosupport.c

@@ -1,6 +0,0 @@
-#include "detection/dns/dns.h"
-
-const char* ffDetectDNS(FF_MAYBE_UNUSED FFlist* results)
-{
-    return "Not supported on this platform";
-}

src/detection/dns/dns_windows.c

@@ -0,0 +1,30 @@
+#include "detection/dns/dns.h"
+#include "util/mallocHelper.h"
+
+#include <iphlpapi.h>
+
+const char* ffDetectDNS(FFlist* results)
+{
+    FF_AUTO_FREE FIXED_INFO* fixedInfo = malloc(sizeof(FIXED_INFO));
+    ULONG size = sizeof(fixedInfo);
+    while (true)
+    {
+        DWORD res = GetNetworkParams(fixedInfo, &size);
+        if (res == ERROR_BUFFER_OVERFLOW)
+        {
+            fixedInfo = realloc(fixedInfo, size);
+            continue;
+        }
+        else if (res != ERROR_SUCCESS)
+            return "GetNetworkParams() failed";
+        break;
+    }
+
+    for (IP_ADDR_STRING* dns = &fixedInfo->DnsServerList; dns; dns = dns->Next)
+    {
+        FFstrbuf* item = (FFstrbuf*) ffListAdd(results);
+        ffStrbufInitS(item, dns->IpAddress.String);
+        ffStrbufTrimRightSpace(item);
+    }
+    return NULL;
+}

src/modules/dns/dns.c

@@ -20,7 +20,7 @@ void ffPrintDNS(FFDNSOptions* options)
 
     if (result.length == 0)
     {
-        ffPrintError(FF_DNS_MODULE_NAME, 0, &options->moduleArgs, FF_PRINT_TYPE_DEFAULT, "NO DNS detected");
+        ffPrintError(FF_DNS_MODULE_NAME, 0, &options->moduleArgs, FF_PRINT_TYPE_DEFAULT, "NO DNS servers detected");
         return;
     }