[io/socket/win] Ensure udp sockets survive sending data to unreachable destination.

TEST=tests\standalone\io\socket_udp_readwrite_test.dart
BUG=flutter/flutter#155823

Change-Id: Ic38bc9c022fe3964bcca003bf498c4a5435d5104
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/390140
Commit-Queue: Alexander Aprelev <[email protected]>
Reviewed-by: Siva Annamalai <[email protected]>

Author: aam

runtime/bin/socket_win.cc

@@ -158,6 +158,12 @@ intptr_t Socket::CreateBindDatagram(const RawAddr& addr,
     return -1;
   }
 
+  // Ensure the socket doesn't get closed if used to send data to unreachable.
+  BOOL value = FALSE;
+  DWORD bytes;
+  WSAIoctl(s, SIO_UDP_CONNRESET, &value, sizeof value, NULL, 0, &bytes, nullptr,
+           nullptr);
+
   int status;
   if (reuseAddress) {
     BOOL optval = true;

tests/standalone/io/socket_udp_readwrite_test.dart

@@ -0,0 +1,36 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test writing to unreachable udp socket doesn't cause problems.
+
+import 'dart:typed_data';
+import 'dart:io';
+
+import "package:expect/expect.dart";
+
+main() async {
+  var _socket = await RawDatagramSocket.bind(InternetAddress.anyIPv4, 9099);
+  _socket.listen((RawSocketEvent event) {
+    print("event: $event");
+    switch (event) {
+      case RawSocketEvent.read:
+        Datagram? d = _socket.receive();
+        if (d != null) {
+          print("recv: $d, all done");
+          _socket.close();
+        }
+        break;
+      case RawSocketEvent.write:
+        print('received write event $event');
+        break;
+    }
+  }, onError: (e) {
+    Expect.fail('Should be no exceptions, but got $e');
+  });
+
+  for (int i = 0; i < 100; i++) {
+    _socket.send(Uint8List(10), InternetAddress("127.0.0.1"), 9100);
+  }
+  _socket.send(Uint8List(10), InternetAddress("127.0.0.1"), 9099);
+}