iphlpapi: Use res_getservers() if available to get the DNS server list.

Signed-off-by: Chip Davis <cdavis@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

configure

@@ -14203,6 +14203,45 @@ $as_echo "#define HAVE_RESOLV 1" >>confdefs.h
         RESOLV_LIBS=$ac_cv_have_resolv
  ;;
     esac
+
+    if test "x$ac_cv_have_resolv" != "xnot found"
+    then
+        { $as_echo "$as_me:${as_lineno-$LINENO}: checking for res_getservers" >&5
+$as_echo_n "checking for res_getservers... " >&6; }
+if ${ac_cv_have_res_getservers+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_save_LIBS="$LIBS"
+                        LIBS="$RESOLV_LIBS $LIBS"
+                        cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <resolv.h>
+int
+main ()
+{
+res_getservers(NULL, NULL, 0);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_have_res_getservers=yes
+else
+  ac_cv_have_res_getservers=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+	                 LIBS="$ac_save_LIBS"
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_have_res_getservers" >&5
+$as_echo "$ac_cv_have_res_getservers" >&6; }
+        if test "$ac_cv_have_res_getservers" = "yes"
+        then
+
+$as_echo "#define HAVE_RES_GETSERVERS 1" >>confdefs.h
+
+        fi
+    fi
 fi
 
 if test "x$with_cms" != "xno"

configure.ac

@@ -1535,6 +1535,20 @@ then
         AC_DEFINE(HAVE_RESOLV, 1)
         AC_SUBST(RESOLV_LIBS,$ac_cv_have_resolv) ;;
     esac
+
+    if test "x$ac_cv_have_resolv" != "xnot found"
+    then
+        AC_CACHE_CHECK([for res_getservers], ac_cv_have_res_getservers,
+                       [ac_save_LIBS="$LIBS"
+                        LIBS="$RESOLV_LIBS $LIBS"
+                        AC_LINK_IFELSE([AC_LANG_PROGRAM(
+        [[#include <resolv.h>]],[[res_getservers(NULL, NULL, 0);]])],[ac_cv_have_res_getservers=yes],[ac_cv_have_res_getservers=no])
+	                 LIBS="$ac_save_LIBS"])
+        if test "$ac_cv_have_res_getservers" = "yes"
+        then
+          AC_DEFINE(HAVE_RES_GETSERVERS, 1, [Define to 1 if you have the `res_getservers' function.])
+        fi
+    fi
 fi
 
 dnl **** Check for LittleCMS ***

dlls/iphlpapi/iphlpapi_main.c

@@ -1249,7 +1249,8 @@ static void sockaddr_in_to_WS_storage( SOCKADDR_STORAGE *dst, const struct socka
 }
 
 #if defined(HAVE_STRUCT___RES_STATE__U__EXT_NSCOUNT6) || \
-    (defined(HAVE___RES_GET_STATE) && defined(HAVE___RES_GETSERVERS))
+    (defined(HAVE___RES_GET_STATE) && defined(HAVE___RES_GETSERVERS)) || \
+    defined(HAVE_RES_GETSERVERS)
 static void sockaddr_in6_to_WS_storage( SOCKADDR_STORAGE *dst, const struct sockaddr_in6 *src )
 {
     SOCKADDR_IN6 *s = (SOCKADDR_IN6 *)dst;
@@ -1284,6 +1285,47 @@ static void initialise_resolver(void)
     LeaveCriticalSection(&res_init_cs);
 }
 
+#ifdef HAVE_RES_GETSERVERS
+static int get_dns_servers( SOCKADDR_STORAGE *servers, int num, BOOL ip4_only )
+{
+    struct __res_state *state = &_res;
+    int i, found = 0, total;
+    SOCKADDR_STORAGE *addr = servers;
+    union res_sockaddr_union *buf;
+
+    initialise_resolver();
+
+    total = res_getservers( state, NULL, 0 );
+
+    if ((!servers || !num) && !ip4_only) return total;
+
+    buf = HeapAlloc( GetProcessHeap(), 0, total * sizeof(union res_sockaddr_union) );
+    total = res_getservers( state, buf, total );
+
+    for (i = 0; i < total; i++)
+    {
+        if (buf[i].sin6.sin6_family == AF_INET6 && ip4_only) continue;
+        if (buf[i].sin.sin_family != AF_INET && buf[i].sin6.sin6_family != AF_INET6) continue;
+
+        found++;
+        if (!servers || !num) continue;
+
+        if (buf[i].sin6.sin6_family == AF_INET6)
+        {
+            sockaddr_in6_to_WS_storage( addr, &buf[i].sin6 );
+        }
+        else
+        {
+            sockaddr_in_to_WS_storage( addr, &buf[i].sin );
+        }
+        if (++addr >= servers + num) break;
+    }
+
+    HeapFree( GetProcessHeap(), 0, buf );
+    return found;
+}
+#else
+
 static int get_dns_servers( SOCKADDR_STORAGE *servers, int num, BOOL ip4_only )
 {
     int i, ip6_count = 0;
@@ -1319,6 +1361,7 @@ static int get_dns_servers( SOCKADDR_STORAGE *servers, int num, BOOL ip4_only )
     }
     return addr - servers;
 }
+#endif
 #elif defined(HAVE___RES_GET_STATE) && defined(HAVE___RES_GETSERVERS)
 
 static int get_dns_servers( SOCKADDR_STORAGE *servers, int num, BOOL ip4_only )

include/config.h.in

@@ -761,6 +761,9 @@
 /* Define to 1 if you have the <resolv.h> header file. */
 #undef HAVE_RESOLV_H
 
+/* Define to 1 if you have the `res_getservers' function. */
+#undef HAVE_RES_GETSERVERS
+
 /* Define to 1 if you have the `rint' function. */
 #undef HAVE_RINT