*/
package okhttp3.internal

import java.net.InetAddress
import okhttp3.Dns

/**
 * A network that always resolves two IP addresses per host. Use this when testing route selection
 * fallbacks to guarantee that a fallback address is available.
 */
class DoubleInetAddressDns : Dns {
  override fun lookup(hostname: String): List<InetAddress> {
    val addresses = Dns.SYSTEM.lookup(hostname)

import javax.net.ssl.SSLSocket
import javax.net.ssl.SSLSocketFactory
import okhttp3.FallbackTestClientSocketFactory.Companion.TLS_FALLBACK_SCSV

/**
 * An SSLSocketFactory that delegates calls. Sockets created by the delegate are wrapped with ones
 * that will not accept the [TLS_FALLBACK_SCSV] cipher, thus bypassing server-side fallback
 * checks on platforms that support it. Unfortunately this wrapping will disable any

    // cipher is added to signal that a protocol fallback has taken place.
    val supportedCipherSuites = sslSocket.supportedCipherSuites
    val indexOfFallbackScsv =
      supportedCipherSuites.indexOf(
        "TLS_FALLBACK_SCSV",
        CipherSuite.ORDER_BY_NAME,
      )
    if (isFallback && indexOfFallbackScsv != -1) {
      cipherSuitesIntersection =

    )
  }
}

graal {
  mainClass("okhttp3.RunTestsKt")
  outputName("ConsoleLauncher")
  graalVersion(libs.versions.graalvm.get())
  javaVersion("11")

  option("--no-fallback")
  option("--report-unsupported-elements-at-runtime")
  option("-H:+ReportExceptionStackTraces")

 * [declaration provider][org.jetbrains.kotlin.analysis.providers.KotlinDeclarationProvider].
 *
 * Since this fallback is not suitable for symbols from binary libraries in Standalone mode, the symbol names provider absolutely needs to
 * work there. This functionality is covered by package scope tests.
 */

### [Fast Fallback](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-ok-http-client/-builder/fast-fallback/)

Since version 5.0, `OkHttpClient` supports fast fallback, which is our implementation of Happy Eyeballs [RFC 6555](https://datatracker.ietf.org/doc/html/rfc6555).

    socket.supportedCipherSuites = arrayOf("SSL_A", "SSL_FALLBACK_SCSV")
    socket.enabledCipherSuites = arrayOf("SSL_A")
    val connectionSpec =
      ConnectionSpec.Builder(true)
        .tlsVersions(TlsVersion.TLS_1_0)
        .cipherSuites("SSL_A")
        .build()
    applyConnectionSpec(connectionSpec, socket, true)
    assertArrayEquals(
      arrayOf("SSL_A", "SSL_FALLBACK_SCSV"),
      socket.enabledCipherSuites,
    )

    expectedCipherSuites.add(CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA.javaName)
    if (listOf<String>(*socket.supportedCipherSuites).contains("TLS_FALLBACK_SCSV")) {
      expectedCipherSuites.add("TLS_FALLBACK_SCSV")
    }
    assertThat(socket.enabledCipherSuites)
      .containsExactly(*expectedCipherSuites.toTypedArray())
  }

  @Test
  fun tls_explicitCiphers() {

                                } catch (Throwable e) {
                                  echo "Failure checkout ITs branch: ${ITS_BRANCH} - fallback master branch"
                                  checkout([$class: 'GitSCM',
                                          branches: [[name: "*/master"]],

## Version 5.0.0-alpha.4

_2022-02-01_

**This release introduces fast fallback to better support mixed IPv4+IPv6 networks.** Fast fallback
is what we're calling our implementation of Happy Eyeballs, [RFC 8305][rfc_8305]. With this
feature OkHttp will attempt both IPv6 and IPv4 connections concurrently, keeping whichever connects
first. Fast fallback gives IPv6 connections a 250 ms head start so IPv6 is preferred on networks