net: increase network family autoselection timeout to 500ms

The current 250ms timeout is too short for high-latency network
environments, causing connection failures in IPv4-only networks when
connecting to dual-stack hosts. This increases the timeout to 500ms
to better handle satellite, cellular, and geographically distant
connections.

The timeout should be reconsidered when parallel connections are
implemented as per RFC 8305.

Refs: #54359
Refs: #48145
PR-URL: #60334
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Tim Perry <[email protected]>
Reviewed-By: Marco Ippolito <[email protected]>
Reviewed-By: Rafael Gonzaga <[email protected]>
Reviewed-By: Santiago Gimeno <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Juan José Arboleda <[email protected]>
Reviewed-By: Ulises Gascón <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>

Author: rvagg

doc/api/net.md

@@ -1905,7 +1905,7 @@ added:
 -->
 
 Gets the current default value of the `autoSelectFamilyAttemptTimeout` option of [`socket.connect(options)`][].
-The initial default value is `250` or the value specified via the command line
+The initial default value is `500` or the value specified via the command line
 option `--network-family-autoselection-attempt-timeout`.
 
 * Returns: {number} The current default value of the `autoSelectFamilyAttemptTimeout` option.

src/node_options.h

@@ -155,7 +155,7 @@ class EnvironmentOptions : public Options {
   int64_t heap_snapshot_near_heap_limit = 0;
   std::string heap_snapshot_signal;
   bool network_family_autoselection = true;
-  uint64_t network_family_autoselection_attempt_timeout = 250;
+  uint64_t network_family_autoselection_attempt_timeout = 500;
   uint64_t max_http_header_size = 16 * 1024;
   bool deprecation = true;
   bool force_async_hooks_checks = true;

test/common/index.js

@@ -184,8 +184,9 @@ function isPi() {
   }
 }
 
-// When using high concurrency or in the CI we need much more time for each connection attempt
-net.setDefaultAutoSelectFamilyAttemptTimeout(platformTimeout(net.getDefaultAutoSelectFamilyAttemptTimeout() * 10));
+// When using high concurrency or in the CI we need much more time for each connection attempt.
+// Default 500ms becomes 2500ms for tests.
+net.setDefaultAutoSelectFamilyAttemptTimeout(platformTimeout(net.getDefaultAutoSelectFamilyAttemptTimeout() * 5));
 const defaultAutoSelectFamilyAttemptTimeout = net.getDefaultAutoSelectFamilyAttemptTimeout();
 
 const buildType = process.config.target_defaults ?

test/parallel/test-net-autoselectfamily-attempt-timeout-cli-option.js

@@ -7,4 +7,4 @@ const { platformTimeout } = require('../common');
 const assert = require('assert');
 const { getDefaultAutoSelectFamilyAttemptTimeout } = require('net');
 
-assert.strictEqual(getDefaultAutoSelectFamilyAttemptTimeout(), platformTimeout(123 * 10));
+assert.strictEqual(getDefaultAutoSelectFamilyAttemptTimeout(), platformTimeout(123 * 5));