net.resolvers: Apply IDNA conversion to ascii for DNS lookups (fixes #1426)

net/resolvers/basic.lua

@@ -1,5 +1,6 @@
 local adns = require "net.adns";
 local inet_pton = require "util.net".pton;
+local idna_to_ascii = require "util.encodings".idna.to_ascii;
 
 local methods = {};
 local resolver_mt = { __index = methods };
@@ -59,7 +60,7 @@ end
 
 local function new(hostname, port, conn_type, extra)
 	return setmetatable({
-		hostname = hostname;
+		hostname = idna_to_ascii(hostname);
 		port = port;
 		conn_type = conn_type or "tcp";
 		extra = extra;

net/resolvers/service.lua

@@ -1,5 +1,6 @@
 local adns = require "net.adns";
 local basic = require "net.resolvers.basic";
+local idna_to_ascii = require "util.encodings".idna.to_ascii;
 
 local methods = {};
 local resolver_mt = { __index = methods };
@@ -58,7 +59,7 @@ end
 
 local function new(hostname, service, conn_type, extra)
 	return setmetatable({
-		hostname = hostname;
+		hostname = idna_to_ascii(hostname);
 		service = service;
 		conn_type = conn_type or "tcp";
 		extra = extra;