    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.List;
    034
    035import org.apache.commons.net.util.Base64;
    036
    037/**
    038 * Experimental attempt at FTP client that tunnels over an HTTP proxy connection.
    039 *
    040 * @since 2.2
    041 */
    042public class FTPHTTPClient extends FTPClient {
    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
    049    private final Charset charset;
    050    private final Base64 base64 = new Base64();
    051
    052    private String tunnelHost; // Save the host when setting up a tunnel (needed for EPSV)
    053
    054    /**
    055     * Create an instance using the UTF-8 encoding, with no proxy credentials.
    056     *
    057     * @param proxyHost the hostname to use
    058     * @param proxyPort the port to use
    059     */
    060    public FTPHTTPClient(final String proxyHost, final int proxyPort) {
    061        this(proxyHost, proxyPort, null, null);
    062    }
    063
    064    /**
    065     * Create an instance using the specified encoding, with no proxy credentials.
    066     *
    067     * @param proxyHost the hostname to use
    068     * @param proxyPort the port to use
    069     * @param encoding  the encoding to use
    070     */
    071    public FTPHTTPClient(final String proxyHost, final int proxyPort, final Charset encoding) {
    072        this(proxyHost, proxyPort, null, null, encoding);
    073    }
    074
    075    /**
    076     * Create an instance using the UTF-8 encoding
    077     *
    078     * @param proxyHost the hostname to use
    079     * @param proxyPort the port to use
    080     * @param proxyUser the user name for the proxy
    081     * @param proxyPass the password for the proxy
    082     */
    083    public FTPHTTPClient(final String proxyHost, final int proxyPort, final String proxyUser, final String proxyPass) {
    084        this(proxyHost, proxyPort, proxyUser, proxyPass, StandardCharsets.UTF_8);
    085    }
    086
    087    /**
    088     * Create an instance with the specified encoding
    089     *
    090     * @param proxyHost the hostname to use
    091     * @param proxyPort the port to use
    092     * @param proxyUser the user name for the proxy
    093     * @param proxyPass the password for the proxy
    094     * @param encoding  the encoding to use
    095     */
    096    public FTPHTTPClient(final String proxyHost, final int proxyPort, final String proxyUser, final String proxyPass, final Charset encoding) {
    097        this.proxyHost = proxyHost;
    098        this.proxyPort = proxyPort;
    099        this.proxyUsername = proxyUser;
    100        this.proxyPassword = proxyPass;
    101        this.tunnelHost = null;
    102        this.charset = encoding;
    103    }
    104
    105    /**
    106     * {@inheritDoc}
    107     *
    108     * @throws IllegalStateException if connection mode is not passive
    109     * @deprecated (3.3) Use {@link FTPClient#_openDataConnection_(FTPCmd, String)} instead
    110     */
    111    // Kept to maintain binary compatibility
    112    // Not strictly necessary, but Clirr complains even though there is a super-impl
    113    @Override
    114    @Deprecated
    115    protected Socket _openDataConnection_(final int command, final String arg) throws IOException {
    116        return super._openDataConnection_(command, arg);
    117    }
    118
    119    /**
    120     * {@inheritDoc}
    121     *
    122     * @throws IllegalStateException if connection mode is not passive
    123     * @since 3.1
    124     */
    125    @Override
    126    protected Socket _openDataConnection_(final String command, final String arg) throws IOException {
    127        // Force local passive mode, active mode not supported by through proxy
    128        if (getDataConnectionMode() != PASSIVE_LOCAL_DATA_CONNECTION_MODE) {
    129            throw new IllegalStateException("Only passive connection mode supported");
    130        }
    131
    132        final boolean isInet6Address = getRemoteAddress() instanceof Inet6Address;
    133        String passiveHost = null;
    134
    135        final boolean attemptEPSV = isUseEPSVwithIPv4() || isInet6Address;
    136        if (attemptEPSV && epsv() == FTPReply.ENTERING_EPSV_MODE) {
    137            _parseExtendedPassiveModeReply(_replyLines.get(0));
    138            passiveHost = this.tunnelHost;
    139        } else {
    140            if (isInet6Address) {
    141                return null; // Must use EPSV for IPV6
    142            }
    143            // If EPSV failed on IPV4, revert to PASV
    144            if (pasv() != FTPReply.ENTERING_PASSIVE_MODE) {
    145                return null;
    146            }
    147            _parsePassiveModeReply(_replyLines.get(0));
    148            passiveHost = this.getPassiveHost();
    149        }
    150
    151        final Socket socket = _socketFactory_.createSocket(proxyHost, proxyPort);
    152        final InputStream is = socket.getInputStream();
    153        final OutputStream os = socket.getOutputStream();
    154        tunnelHandshake(passiveHost, this.getPassivePort(), is, os);
    155        if (getRestartOffset() > 0 && !restart(getRestartOffset())) {
    156            socket.close();
    157            return null;
    158        }
    159
    160        if (!FTPReply.isPositivePreliminary(sendCommand(command, arg))) {
    161            socket.close();
    162            return null;
    163        }
    164
    165        return socket;
    166    }
    167
    168    @Override
    169    public void connect(final String host, final int port) throws SocketException, IOException {
    170
    171        _socket_ = _socketFactory_.createSocket(proxyHost, proxyPort);
    172        _input_ = _socket_.getInputStream();
    173        _output_ = _socket_.getOutputStream();
    174        final Reader socketIsReader;
    175        try {
    176            socketIsReader = tunnelHandshake(host, port, _input_, _output_);
    177        } catch (final Exception e) {
    178            final IOException ioe = new IOException("Could not connect to " + host + " using port " + port);
    179            ioe.initCause(e);
    180            throw ioe;
    181        }
    182        super._connectAction_(socketIsReader);
    183    }
    184
    185    private BufferedReader tunnelHandshake(final String host, final int port, final InputStream input, final OutputStream output)
    186            throws IOException, UnsupportedEncodingException {
    187        final String connectString = "CONNECT " + host + ":" + port + " HTTP/1.1";
    188        final String hostString = "Host: " + host + ":" + port;
    189
    190        this.tunnelHost = host;
    191        output.write(connectString.getBytes(charset));
    192        output.write(CRLF);
    193        output.write(hostString.getBytes(charset));
    194        output.write(CRLF);
    195
    196        if (proxyUsername != null && proxyPassword != null) {
    197            final String auth = proxyUsername + ":" + proxyPassword;
    198            final String header = "Proxy-Authorization: Basic " + base64.encodeToString(auth.getBytes(charset));
    199            output.write(header.getBytes(charset));
    200        }
    201        output.write(CRLF);
    202
    203        final List<String> response = new ArrayList<>();
    204        final BufferedReader reader = new BufferedReader(new InputStreamReader(input, getCharset()));
    205
    206        for (String line = reader.readLine(); line != null && !line.isEmpty(); line = reader.readLine()) {
    207            response.add(line);
    208        }
    209
    210        final int size = response.size();
    211        if (size == 0) {
    212            throw new IOException("No response from proxy");
    213        }
    214
    215        String code = null;
    216        final String resp = response.get(0);
    217        if (!resp.startsWith("HTTP/") || (resp.length() < 12)) {
    218            throw new IOException("Invalid response from proxy: " + resp);
    219        }
    220        code = resp.substring(9, 12);
    221
    222        if (!"200".equals(code)) {
    223            final StringBuilder msg = new StringBuilder();
    224            msg.append("HTTPTunnelConnector: connection failed\r\n");
    225            msg.append("Response received from the proxy:\r\n");
    226            for (final String line : response) {
    227                msg.append(line);
    228                msg.append("\r\n");
    229            }
    230            throw new IOException(msg.toString());
    231        }
    232        return reader;
    233    }
    234}