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/*
* Copyright © 2017-2021 WireGuard LLC. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package com.wireguard.config;
import com.wireguard.util.NonNullForAll;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.UnknownHostException;
import java.time.Duration;
import java.time.Instant;
import java.util.Optional;
import java.util.regex.Pattern;
import androidx.annotation.Nullable;
/**
* An external endpoint (host and port) used to connect to a WireGuard {@link Peer}.
* <p>
* Instances of this class are externally immutable.
*/
@NonNullForAll
public final class InetEndpoint {
private static final Pattern BARE_IPV6 = Pattern.compile("^[^\\[\\]]*:[^\\[\\]]*");
private static final Pattern FORBIDDEN_CHARACTERS = Pattern.compile("[/?#]");
private final String host;
private final boolean isResolved;
private final Object lock = new Object();
private final int port;
private Instant lastResolution = Instant.EPOCH;
@Nullable private InetEndpoint resolved;
private InetEndpoint(final String host, final boolean isResolved, final int port) {
this.host = host;
this.isResolved = isResolved;
this.port = port;
}
public static InetEndpoint parse(final String endpoint) throws ParseException {
if (FORBIDDEN_CHARACTERS.matcher(endpoint).find())
throw new ParseException(InetEndpoint.class, endpoint, "Forbidden characters");
final URI uri;
try {
uri = new URI("wg://" + endpoint);
} catch (final URISyntaxException e) {
throw new ParseException(InetEndpoint.class, endpoint, e);
}
if (uri.getPort() < 0 || uri.getPort() > 65535)
throw new ParseException(InetEndpoint.class, endpoint, "Missing/invalid port number");
try {
InetAddresses.parse(uri.getHost());
// Parsing ths host as a numeric address worked, so we don't need to do DNS lookups.
return new InetEndpoint(uri.getHost(), true, uri.getPort());
} catch (final ParseException ignored) {
// Failed to parse the host as a numeric address, so it must be a DNS hostname/FQDN.
return new InetEndpoint(uri.getHost(), false, uri.getPort());
}
}
@Override
public boolean equals(final Object obj) {
if (!(obj instanceof InetEndpoint))
return false;
final InetEndpoint other = (InetEndpoint) obj;
return host.equals(other.host) && port == other.port;
}
public String getHost() {
return host;
}
public int getPort() {
return port;
}
/**
* Generate an {@code InetEndpoint} instance with the same port and the host resolved using DNS
* to a numeric address. If the host is already numeric, the existing instance may be returned.
* Because this function may perform network I/O, it must not be called from the main thread.
*
* @return the resolved endpoint, or {@link Optional#empty()}
*/
public Optional<InetEndpoint> getResolved() {
if (isResolved)
return Optional.of(this);
synchronized (lock) {
//TODO(zx2c4): Implement a real timeout mechanism using DNS TTL
if (Duration.between(lastResolution, Instant.now()).toMinutes() > 1) {
try {
// Prefer v4 endpoints over v6 to work around DNS64 and IPv6 NAT issues.
final InetAddress[] candidates = InetAddress.getAllByName(host);
InetAddress address = candidates[0];
for (final InetAddress candidate : candidates) {
if (candidate instanceof Inet4Address) {
address = candidate;
break;
}
}
resolved = new InetEndpoint(address.getHostAddress(), true, port);
lastResolution = Instant.now();
} catch (final UnknownHostException e) {
resolved = null;
}
}
return Optional.ofNullable(resolved);
}
}
@Override
public int hashCode() {
return host.hashCode() ^ port;
}
@Override
public String toString() {
final boolean isBareIpv6 = isResolved && BARE_IPV6.matcher(host).matches();
return (isBareIpv6 ? '[' + host + ']' : host) + ':' + port;
}
}
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