[io/gardening] Fix client address binding & fix standalone/io/socket_local_port_test

Various changes to the stanalone/io/socket_local_port_test:

  * Make server ports ephemeral: The test is testing client-side
    binding of address & port, the server part can use ephemeral ports.
    => This eliminates the issue of another process using the
       hard-coded port
  * Close sockets normally instead of using `Socket.destroy()`
  * Make dead code alive: There were test in the tests that were
    not invoked by `main()`.
  * Align the individual test helper functions.
  * ...

Then we change the dart:io implementation of `Socket::CreateBindConnect`
to set the `SO_REUSEADDR` socket option. We do this already for the
server side in `Socket::CreateBindListen`, now we do it also for the
client side.
=> This will ensure that one can bind the client side socket to
   specific address/source despite there being an old closed
   socket that's now in `TIME_WAIT` state.
=> This is the same reason we also do it in `Socket::CreateBindListen`.

Fuchsia doesn't implement `Socket::CreateBindConnect` and on Windows
the socket option seemingly has different semantics (we also don't use
`SO_REUSEADDR` on windows for the server socket, but another option).

Issue #51477

TEST=standalone/io/socket_local_port_test

Change-Id: I7d07becad0cd98c3a9b973ef2f9037730d3f8b19
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/436902
Commit-Queue: Martin Kustermann <[email protected]>
Reviewed-by: Slava Egorov <[email protected]>

Author: mkustermann

runtime/bin/socket_linux.cc

@@ -81,6 +81,10 @@ intptr_t Socket::CreateBindConnect(const RawAddr& addr,
     return fd;
   }
 
+  int optval = 1;
+  VOID_NO_RETRY_EXPECTED(
+      setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)));
+
   intptr_t result = TEMP_FAILURE_RETRY(
       bind(fd, &source_addr.addr, SocketAddress::GetAddrLength(source_addr)));
   if (result != 0) {

runtime/bin/socket_macos.cc

@@ -86,6 +86,10 @@ intptr_t Socket::CreateBindConnect(const RawAddr& addr,
     return fd;
   }
 
+  int optval = 1;
+  VOID_NO_RETRY_EXPECTED(
+      setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)));
+
   intptr_t result = TEMP_FAILURE_RETRY(
       bind(fd, &source_addr.addr, SocketAddress::GetAddrLength(source_addr)));
   if (result != 0) {

tests/standalone/io/socket_local_port_test.dart

@@ -8,46 +8,40 @@ import "dart:io";
 import "package:expect/expect.dart";
 
 Future testCustomPortIPv4() {
-  String clientAddress = "127.0.0.1";
+  String host = "127.0.0.1";
   int customLocalPort = 50988;
-  String serverAddress = clientAddress;
-  int port = 50989;
+  String customAddress = host;
 
-  return testCustomPort(serverAddress, port, clientAddress, customLocalPort);
+  return testCustomPort(host, customAddress, customLocalPort);
 }
 
 Future testCustomPortIPv6() {
-  String clientAddress = "::1";
-  int customLocalPort = 50988;
-  String serverAddress = clientAddress;
-  int port = 50989;
+  String host = "::1";
+  int customLocalPort = 50989;
+  String customAddress = host;
 
-  return testCustomPort(serverAddress, port, clientAddress, customLocalPort);
+  return testCustomPort(host, customAddress, customLocalPort);
 }
 
 Future testCustomPortIPv4NoSourceAddress() {
-  String expectedClientAddress = "127.0.0.1";
-  int customLocalPort = 50988;
-  String serverAddress = expectedClientAddress;
-  int port = 50989;
+  String host = "127.0.0.1";
+  int customLocalPort = 50990;
+  String expectedClientAddress = host;
 
-  return testCustomPort(
-    serverAddress,
-    port,
+  return testCustomPortNoSourceAddress(
+    host,
     expectedClientAddress,
     customLocalPort,
   );
 }
 
 Future testCustomPortIPv6NoSourceAddress() {
-  String expectedClientAddress = "::1";
-  int customLocalPort = 50988;
-  String serverAddress = expectedClientAddress;
-  int port = 50989;
+  String host = "::1";
+  int customLocalPort = 50991;
+  String expectedClientAddress = host;
 
-  return testCustomPort(
-    serverAddress,
-    port,
+  return testCustomPortNoSourceAddress(
+    host,
     expectedClientAddress,
     customLocalPort,
   );
@@ -56,134 +50,118 @@ Future testCustomPortIPv6NoSourceAddress() {
 Future testNoCustomPortIPv4() {
   String host = "127.0.0.1";
   String clientAddress = host;
-  int serverPort = 39998;
 
-  return testNoCustomPortNoSourceAddress(host, serverPort, clientAddress);
+  return testNoCustomPort(host, clientAddress);
 }
 
 Future testNoCustomPortIPv6() {
   String host = "::1";
   String clientAddress = host;
-  int serverPort = 39998;
 
-  return testNoCustomPortNoSourceAddress(host, serverPort, clientAddress);
+  return testNoCustomPort(host, clientAddress);
 }
 
 Future testNoCustomPortNoSourceAddressIPv4() {
   String host = "127.0.0.1";
   String expectedAddress = host;
-  int serverPort = 39998;
 
-  return testNoCustomPortNoSourceAddress(host, serverPort, expectedAddress);
+  return testNoCustomPortNoSourceAddress(host, expectedAddress);
 }
 
 Future testNoCustomPortNoSourceAddressIPv6() {
   String host = "::1";
   String expectedAddress = host;
-  int serverPort = 39998;
 
-  return testNoCustomPortNoSourceAddress(host, serverPort, expectedAddress);
+  return testNoCustomPortNoSourceAddress(host, expectedAddress);
 }
 
 // Core functionality
-Future testCustomPort(
-  String host,
-  int port,
-  String sourceAddress,
-  int sourcePort,
-) async {
-  var server = await ServerSocket.bind(host, port);
-  server.listen((client) {
-    Expect.equals(server.port, port);
+
+Future testCustomPort(String host, String sourceAddress, int sourcePort) async {
+  final serverTestDone = Completer();
+  final server = await ServerSocket.bind(host, 0);
+  server.listen((Socket client) async {
     Expect.equals(client.remotePort, sourcePort);
     Expect.equals(client.address.address, sourceAddress);
-    client.destroy();
+    await (client.close(), client.drain()).wait;
+    serverTestDone.complete();
   });
-
-  Socket s = await Socket.connect(
+  final client = await Socket.connect(
     host,
-    port,
+    server.port,
     sourceAddress: sourceAddress,
     sourcePort: sourcePort,
   );
-  s.destroy();
+  await (client.close(), client.drain()).wait;
+  await serverTestDone.future;
   await server.close();
 }
 
 Future testCustomPortNoSourceAddress(
   String host,
-  int port,
   String expectedAddress,
   int sourcePort,
 ) async {
-  Completer completer = new Completer();
-  var server = await ServerSocket.bind(host, port);
-
-  server.listen((client) {
-    Expect.equals(server.port, port);
+  final serverTestDone = Completer();
+  final server = await ServerSocket.bind(host, 0);
+  server.listen((Socket client) async {
     Expect.equals(client.remotePort, sourcePort);
     Expect.equals(client.address.address, expectedAddress);
-    client.destroy();
-    completer.complete();
+    await (client.close(), client.drain()).wait;
+    serverTestDone.complete();
   });
-
-  Socket s = await Socket.connect(host, port, sourcePort: sourcePort);
-  s.destroy();
+  final client = await Socket.connect(
+    host,
+    server.port,
+    sourcePort: sourcePort,
+  );
+  await (client.close(), client.drain()).wait;
+  await serverTestDone.future;
   await server.close();
-
-  return completer.future;
 }
 
-Future testNoCustomPort(String host, int port, String sourceAddress) async {
-  Completer serverCompleter = new Completer();
-  Completer clientCompleter = new Completer();
-  var server = await ServerSocket.bind(host, port);
-  Socket.connect(host, port, sourceAddress: sourceAddress).then((
-    clientSocket,
-  ) async {
-    server.listen((client) async {
-      Expect.equals(server.port, port);
-      Expect.equals(client.remotePort, clientSocket.port);
-      Expect.equals(client.address.address, sourceAddress);
-
-      client.destroy();
-      clientCompleter.complete();
-    });
-
-    clientSocket.destroy();
-    await server.close();
-    serverCompleter.complete();
+Future testNoCustomPort(String host, String sourceAddress) async {
+  final serverTestDone = Completer();
+  final server = await ServerSocket.bind(host, 0);
+  server.listen((Socket client) async {
+    Expect.equals(client.address.address, sourceAddress);
+    await (client.close(), client.drain()).wait;
+    serverTestDone.complete();
   });
-
-  await serverCompleter.future;
-  await clientCompleter.future;
+  final client = await Socket.connect(
+    host,
+    server.port,
+    sourceAddress: sourceAddress,
+  );
+  await (client.close(), client.drain()).wait;
+  await serverTestDone.future;
+  await server.close();
 }
 
 Future testNoCustomPortNoSourceAddress(
   String host,
-  int port,
   String expectedAddress,
 ) async {
-  Completer completer = new Completer();
-  var server = await ServerSocket.bind(host, port);
-  Socket.connect(host, port).then((clientSocket) {
-    server.listen((client) async {
-      Expect.equals(server.port, port);
-      Expect.equals(client.remotePort, clientSocket.port);
-      Expect.equals(client.address.address, expectedAddress);
-      clientSocket.destroy();
-      client.destroy();
-      await server.close();
-      completer.complete();
-    });
+  final serverTestDone = Completer();
+  final server = await ServerSocket.bind(host, 0);
+  server.listen((Socket client) async {
+    Expect.equals(client.address.address, expectedAddress);
+    await (client.close(), client.drain()).wait;
+    serverTestDone.complete();
   });
-  return completer.future;
+  final client = await Socket.connect(host, server.port);
+  await (client.close(), client.drain()).wait;
+  await serverTestDone.future;
+  await server.close();
 }
 
 Future main() async {
   await testCustomPortIPv4();
   await testCustomPortIPv6();
 
+  await testCustomPortIPv4NoSourceAddress();
+  await testCustomPortIPv6NoSourceAddress();
+
   await testNoCustomPortIPv4();
   await testNoCustomPortIPv6();