import okhttp3.Dns.Companion.SYSTEM

/**
 * A domain name service that resolves IP addresses for host names. Most applications will use the
 * [system DNS service][SYSTEM], which is the default. Some applications may provide their own
 * implementation to use a different DNS server, to prefer IPv6 addresses, to prefer IPv4 addresses,
 * or to force a specific known IP address.
 *
 * Implementations of this interface must be safe for concurrent use.
 */

 * addresses nor hostnames; they will be verified as IP addresses (which is a more strict
 * verification).
 */
private val VERIFY_AS_IP_ADDRESS = "([0-9a-fA-F]*:[0-9a-fA-F:.]*)|([\\d.]+)".toRegex()

/** Returns true if this string is not a host name and might be an IP address. */
fun String.canParseAsIpAddress(): Boolean = VERIFY_AS_IP_ADDRESS.matches(this)

/**

    rather than the duration specified in the response's cache-control header.
 *  Fix: Verify certificate IP addresses in canonical form. When a server presents a TLS certificate
    containing an IP address we must match that address against the URL's IP address, even when the
    two addresses are encoded differently, such as `192.168.1.1` and `0::0:0:FFFF:C0A8:101`. Note

 * limitations under the License.
 */
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> {

    // https://daniel.haxx.se/blog/2016/08/18/http2-connection-coalescing/

    // 1. This connection must be HTTP/2.
    if (http2Connection == null) return false

    // 2. The routes must share an IP address.
    if (routes == null || !routeMatchesAny(routes)) return false

    // 3. This connection's server certificate's must cover the new host.
    if (address.hostnameVerifier !== OkHostnameVerifier) return false

        derReader.readOctetString()
      }
    }.also { expected ->
      assertThat(expected).hasMessage("constructed octet strings not supported for DER")
    }
  }

  @Test fun `choice IP address`() {
    val bytes = "8704c0a80201".decodeHex()
    val localhost = InetAddress.getByName("192.168.2.1").address.toByteString()
    assertThat(CertificateAdapters.generalName.fromDer(bytes))

      MockResponse(
        body = "bogus proxy connect response content",
        inTunnel = true,
      ),
    )
    server.enqueue(MockResponse(body = "response"))

    // Configure a single IP address for the host and a single configuration, so we only need one
    // failure to fail permanently.
    client =
      client.newBuilder()
        .sslSocketFactory(
          handshakeCertificates.sslSocketFactory(),

import java.net.InetAddress
import okhttp3.internal.interleave

/**
 * Implementation of HappyEyeballs Sorting Addresses.
 *
 * The current implementation does not address any of:
 *  - Async DNS split by IP class
 *  - Stateful handling of connectivity results
 *  - The prioritisation of addresses
 *
 * https://datatracker.ietf.org/doc/html/rfc8305#section-4
 */

/**
 * A denylist of failed routes to avoid when creating a new connection to a target address. This is
 * used so that OkHttp can learn from its mistakes: if there was a failure attempting to connect to
 * a specific IP address or proxy server, that failure is remembered and alternate routes are
 * preferred.
 */
class RouteDatabase {
  private val _failedRoutes = mutableSetOf<Route>()

  val failedRoutes: Set<Route>

 *
 * HTTP requests that share the same [Address] may also share the same [Connection].
 */
class Address(
  uriHost: String,
  uriPort: Int,
  /** Returns the service that will be used to resolve IP addresses for hostnames. */
  @get:JvmName("dns") val dns: Dns,
  /** Returns the socket factory for new connections. */
  @get:JvmName("socketFactory") val socketFactory: SocketFactory,