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}