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 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
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package io.undertow.server.handlers;

import io.undertow.UndertowLogger;
import io.undertow.server.HandlerWrapper;
import io.undertow.server.HttpHandler;
import io.undertow.server.HttpServerExchange;
import io.undertow.server.handlers.builder.HandlerBuilder;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedExceptionAction;
import java.util.Collections;
import java.util.Map;
import java.util.Set;

A handler that performs reverse DNS lookup to resolve a peer address
Author:Stuart Douglas
/** * A handler that performs reverse DNS lookup to resolve a peer address * * @author Stuart Douglas */
public class PeerNameResolvingHandler implements HttpHandler { private final HttpHandler next; private final ResolveType resolveType; public PeerNameResolvingHandler(HttpHandler next) { this.next = next; this.resolveType = ResolveType.FORWARD_AND_REVERSE; } public PeerNameResolvingHandler(HttpHandler next, ResolveType resolveType) { this.next = next; this.resolveType = resolveType; } @Override public void handleRequest(final HttpServerExchange exchange) throws Exception { final InetSocketAddress address = exchange.getSourceAddress(); if (address != null) { if ((resolveType == ResolveType.FORWARD || resolveType == ResolveType.FORWARD_AND_REVERSE) && address.isUnresolved()) { try { if (System.getSecurityManager() == null) { final InetSocketAddress resolvedAddress = new InetSocketAddress(InetAddress.getByName(address.getHostName()), address.getPort()); exchange.setSourceAddress(resolvedAddress); } else { AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() { @Override public Object run() throws UnknownHostException { final InetSocketAddress resolvedAddress = new InetSocketAddress(InetAddress.getByName(address.getHostName()), address.getPort()); exchange.setSourceAddress(resolvedAddress); return null; } }); } } catch (UnknownHostException e) { UndertowLogger.REQUEST_LOGGER.debugf(e, "Could not resolve hostname %s", address.getHostString()); } } else if (resolveType == ResolveType.REVERSE || resolveType == ResolveType.FORWARD_AND_REVERSE) { if (System.getSecurityManager() == null) { address.getHostName(); } else { AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { address.getHostName(); return null; } }); } //we call set source address because otherwise the underlying channel could just return a new address exchange.setSourceAddress(address); } } next.handleRequest(exchange); } public enum ResolveType { FORWARD, REVERSE, FORWARD_AND_REVERSE } public static class Builder implements HandlerBuilder { @Override public String name() { return "resolve-peer-name"; } @Override public Map<String, Class<?>> parameters() { return Collections.emptyMap(); } @Override public Set<String> requiredParameters() { return Collections.emptySet(); } @Override public String defaultParameter() { return null; } @Override public HandlerWrapper build(Map<String, Object> config) { return new Wrapper(); } } private static class Wrapper implements HandlerWrapper { @Override public HttpHandler wrap(HttpHandler handler) { return new PeerNameResolvingHandler(handler); } } }