    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.net.ftp;
    019
    020import java.io.BufferedReader;
    021import java.io.IOException;
    022import java.io.InputStream;
    023import java.io.InputStreamReader;
    024import java.io.OutputStream;
    025import java.io.Reader;
    026import java.io.UnsupportedEncodingException;
    027import java.net.Inet6Address;
    028import java.net.Socket;
    029import java.net.SocketException;
    030import java.nio.charset.Charset;
    031import java.nio.charset.StandardCharsets;
    032import java.util.ArrayList;
    033import java.util.Base64;
    034import java.util.List;
    035
    036/**
    037 * Experimental attempt at FTP client that tunnels over an HTTP proxy connection.
    038 *
    039 * @since 2.2
    040 */
    041public class FTPHTTPClient extends FTPClient {
    042
    043    private static final byte[] CRLF = { '\r', '\n' };
    044    private final String proxyHost;
    045    private final int proxyPort;
    046    private final String proxyUsername;
    047    private final String proxyPassword;
    048    private final Charset charset;
    049    private String tunnelHost; // Save the host when setting up a tunnel (needed for EPSV)
    050
    051    /**
    052     * Create an instance using the UTF-8 encoding, with no proxy credentials.
    053     *
    054     * @param proxyHost the hostname to use
    055     * @param proxyPort the port to use
    056     */
    057    public FTPHTTPClient(final String proxyHost, final int proxyPort) {
    058        this(proxyHost, proxyPort, null, null);
    059    }
    060
    061    /**
    062     * Create an instance using the specified encoding, with no proxy credentials.
    063     *
    064     * @param proxyHost the hostname to use
    065     * @param proxyPort the port to use
    066     * @param encoding  the encoding to use
    067     */
    068    public FTPHTTPClient(final String proxyHost, final int proxyPort, final Charset encoding) {
    069        this(proxyHost, proxyPort, null, null, encoding);
    070    }
    071
    072    /**
    073     * Create an instance using the UTF-8 encoding
    074     *
    075     * @param proxyHost the hostname to use
    076     * @param proxyPort the port to use
    077     * @param proxyUser the user name for the proxy
    078     * @param proxyPass the password for the proxy
    079     */
    080    public FTPHTTPClient(final String proxyHost, final int proxyPort, final String proxyUser, final String proxyPass) {
    081        this(proxyHost, proxyPort, proxyUser, proxyPass, StandardCharsets.UTF_8);
    082    }
    083
    084    /**
    085     * Create an instance with the specified encoding
    086     *
    087     * @param proxyHost the hostname to use
    088     * @param proxyPort the port to use
    089     * @param proxyUser the user name for the proxy
    090     * @param proxyPass the password for the proxy
    091     * @param encoding  the encoding to use
    092     */
    093    public FTPHTTPClient(final String proxyHost, final int proxyPort, final String proxyUser, final String proxyPass, final Charset encoding) {
    094        this.proxyHost = proxyHost;
    095        this.proxyPort = proxyPort;
    096        this.proxyUsername = proxyUser;
    097        this.proxyPassword = proxyPass;
    098        this.tunnelHost = null;
    099        this.charset = encoding;
    100    }
    101
    102    /**
    103     * {@inheritDoc}
    104     *
    105     * @throws IllegalStateException if connection mode is not passive
    106     * @deprecated (3.3) Use {@link FTPClient#_openDataConnection_(FTPCmd, String)} instead
    107     */
    108    // Kept to maintain binary compatibility
    109    // Not strictly necessary, but Clirr complains even though there is a super-impl
    110    @Override
    111    @Deprecated
    112    protected Socket _openDataConnection_(final int command, final String arg) throws IOException {
    113        return super._openDataConnection_(command, arg);
    114    }
    115
    116    /**
    117     * {@inheritDoc}
    118     *
    119     * @throws IllegalStateException if connection mode is not passive
    120     * @since 3.1
    121     */
    122    @Override
    123    protected Socket _openDataConnection_(final String command, final String arg) throws IOException {
    124        // Force local passive mode, active mode not supported by through proxy
    125        if (getDataConnectionMode() != PASSIVE_LOCAL_DATA_CONNECTION_MODE) {
    126            throw new IllegalStateException("Only passive connection mode supported");
    127        }
    128
    129        final boolean isInet6Address = getRemoteAddress() instanceof Inet6Address;
    130        String passiveHost;
    131
    132        final boolean attemptEPSV = isUseEPSVwithIPv4() || isInet6Address;
    133        if (attemptEPSV && epsv() == FTPReply.ENTERING_EPSV_MODE) {
    134            _parseExtendedPassiveModeReply(_replyLines.get(0));
    135            passiveHost = this.tunnelHost;
    136        } else {
    137            if (isInet6Address) {
    138                return null; // Must use EPSV for IPV6
    139            }
    140            // If EPSV failed on IPV4, revert to PASV
    141            if (pasv() != FTPReply.ENTERING_PASSIVE_MODE) {
    142                return null;
    143            }
    144            _parsePassiveModeReply(_replyLines.get(0));
    145            passiveHost = this.getPassiveHost();
    146        }
    147
    148        final Socket socket = _socketFactory_.createSocket(proxyHost, proxyPort);
    149        final InputStream is = socket.getInputStream();
    150        final OutputStream os = socket.getOutputStream();
    151        tunnelHandshake(passiveHost, this.getPassivePort(), is, os);
    152        if (getRestartOffset() > 0 && !restart(getRestartOffset())) {
    153            socket.close();
    154            return null;
    155        }
    156
    157        if (!FTPReply.isPositivePreliminary(sendCommand(command, arg))) {
    158            socket.close();
    159            return null;
    160        }
    161
    162        return socket;
    163    }
    164
    165    @Override
    166    public void connect(final String host, final int port) throws SocketException, IOException {
    167
    168        _socket_ = _socketFactory_.createSocket(proxyHost, proxyPort);
    169        _input_ = _socket_.getInputStream();
    170        _output_ = _socket_.getOutputStream();
    171        final Reader socketIsReader;
    172        try {
    173            socketIsReader = tunnelHandshake(host, port, _input_, _output_);
    174        } catch (final Exception e) {
    175            final IOException ioe = new IOException("Could not connect to " + host + " using port " + port);
    176            ioe.initCause(e);
    177            throw ioe;
    178        }
    179        super._connectAction_(socketIsReader);
    180    }
    181
    182    private BufferedReader tunnelHandshake(final String host, final int port, final InputStream input, final OutputStream output)
    183            throws IOException, UnsupportedEncodingException {
    184        final String connectString = "CONNECT " + host + ":" + port + " HTTP/1.1";
    185        final String hostString = "Host: " + host + ":" + port;
    186
    187        this.tunnelHost = host;
    188        output.write(connectString.getBytes(charset));
    189        output.write(CRLF);
    190        output.write(hostString.getBytes(charset));
    191        output.write(CRLF);
    192
    193        if (proxyUsername != null && proxyPassword != null) {
    194            final String auth = proxyUsername + ":" + proxyPassword;
    195            final String header = "Proxy-Authorization: Basic " + Base64.getEncoder().encodeToString(auth.getBytes(charset));
    196            output.write(header.getBytes(charset));
    197        }
    198        output.write(CRLF);
    199
    200        final List<String> response = new ArrayList<>();
    201        final BufferedReader reader = new BufferedReader(new InputStreamReader(input, getCharset()));
    202
    203        for (String line = reader.readLine(); line != null && !line.isEmpty(); line = reader.readLine()) {
    204            response.add(line);
    205        }
    206
    207        final int size = response.size();
    208        if (size == 0) {
    209            throw new IOException("No response from proxy");
    210        }
    211
    212        String code;
    213        final String resp = response.get(0);
    214        if (!resp.startsWith("HTTP/") || resp.length() < 12) {
    215            throw new IOException("Invalid response from proxy: " + resp);
    216        }
    217        code = resp.substring(9, 12);
    218
    219        if (!"200".equals(code)) {
    220            final StringBuilder msg = new StringBuilder();
    221            msg.append("HTTPTunnelConnector: connection failed\r\n");
    222            msg.append("Response received from the proxy:\r\n");
    223            for (final String line : response) {
    224                msg.append(line);
    225                msg.append("\r\n");
    226            }
    227            throw new IOException(msg.toString());
    228        }
    229        return reader;
    230    }
    231}