1 /*
2 * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 import java.net.*;
25 import java.io.*;
26 import java.util.*;
27 import java.security.*;
28
29 /**
30 * A minimal proxy server that supports CONNECT tunneling. It does not do
31 * any header transformations. In future this could be added.
32 * Two threads are created per client connection. So, it's not
33 * intended for large numbers of parallel connections.
34 */
35 public class ProxyServer extends Thread implements Closeable {
36
37 ServerSocket listener;
38 int port;
39 volatile boolean debug;
40
41 /**
42 * Create proxy on port (zero means don't care). Call getPort()
43 * to get the assigned port.
44 */
45 public ProxyServer(Integer port) throws IOException {
46 this(port, false);
47 }
48
49 public ProxyServer(Integer port, Boolean debug) throws IOException {
50 this.debug = debug;
51 listener = new ServerSocket();
52 listener.setReuseAddress(false);
53 listener.bind(new InetSocketAddress(InetAddress.getLoopbackAddress(), port));
54 this.port = listener.getLocalPort();
55 setName("ProxyListener");
56 setDaemon(true);
57 connections = new LinkedList<>();
58 start();
59 }
60
61 public ProxyServer(String s) { }
62
63 /**
64 * Returns the port number this proxy is listening on
65 */
66 public int getPort() {
67 return port;
68 }
69
70 /**
71 * Shuts down the proxy, probably aborting any connections
72 * currently open
73 */
74 public void close() throws IOException {
75 if (debug) System.out.println("Proxy: closing");
76 done = true;
77 listener.close();
78 for (Connection c : connections) {
79 c.close();
80 }
81 }
82
83 List<Connection> connections;
84
85 volatile boolean done;
86
87 public void run() {
88 if (System.getSecurityManager() == null) {
89 execute();
90 } else {
91 // so calling domain does not need to have socket permission
92 AccessController.doPrivileged(new PrivilegedAction<Void>() {
93 public Void run() {
94 execute();
95 return null;
96 }
97 });
98 }
99 }
100
101 public void execute() {
102 try {
103 while(!done) {
104 Socket s = listener.accept();
105 if (debug)
106 System.out.println("Client: " + s);
107 Connection c = new Connection(s);
108 connections.add(c);
109 }
110 } catch(Throwable e) {
111 if (debug && !done) {
112 System.out.println("Fatal error: Listener: " + e);
113 e.printStackTrace();
114 }
115 }
116 }
117
118 /**
119 * Transparently forward everything, once we know what the destination is
120 */
121 class Connection {
122
123 Socket clientSocket, serverSocket;
124 Thread out, in;
125 volatile InputStream clientIn, serverIn;
126 volatile OutputStream clientOut, serverOut;
127
128 boolean forwarding = false;
129
130 final static int CR = 13;
131 final static int LF = 10;
132
133 Connection(Socket s) throws IOException {
134 this.clientSocket= s;
135 this.clientIn = new BufferedInputStream(s.getInputStream());
136 this.clientOut = s.getOutputStream();
137 init();
138 }
139
140 byte[] readHeaders(InputStream is) throws IOException {
141 byte[] outbuffer = new byte[8000];
142 int crlfcount = 0;
143 int bytecount = 0;
144 int c;
145 while ((c=is.read()) != -1 && bytecount < outbuffer.length) {
146 outbuffer[bytecount++] = (byte)c;
147 if (debug) System.out.write(c);
148 // were looking for CRLFCRLF sequence
149 if (c == CR || c == LF) {
150 switch(crlfcount) {
151 case 0:
152 if (c == CR) crlfcount ++;
153 break;
154 case 1:
155 if (c == LF) crlfcount ++;
156 break;
157 case 2:
158 if (c == CR) crlfcount ++;
159 break;
160 case 3:
161 if (c == LF) crlfcount ++;
162 break;
163 }
164 } else {
165 crlfcount = 0;
166 }
167 if (crlfcount == 4) {
168 break;
169 }
170 }
171 byte[] ret = new byte[bytecount];
172 System.arraycopy(outbuffer, 0, ret, 0, bytecount);
173 return ret;
174 }
175
176 boolean running() {
177 return out.isAlive() || in.isAlive();
178 }
179
180 private volatile boolean closing;
181 public synchronized void close() throws IOException {
182 closing = true;
183 if (debug) System.out.println("Closing connection (proxy)");
184 if (serverSocket != null) serverSocket.close();
185 if (clientSocket != null) clientSocket.close();
186 }
187
188 int findCRLF(byte[] b) {
189 for (int i=0; i<b.length-1; i++) {
190 if (b[i] == CR && b[i+1] == LF) {
191 return i;
192 }
193 }
194 return -1;
195 }
196
197 public void init() {
198 try {
199 byte[] buf = readHeaders(clientIn);
200 int p = findCRLF(buf);
201 if (p == -1) {
202 close();
203 return;
204 }
205 String cmd = new String(buf, 0, p, "US-ASCII");
206 String[] params = cmd.split(" ");
207 if (params[0].equals("CONNECT")) {
208 doTunnel(params[1]);
209 } else {
210 doProxy(params[1], buf, p, cmd);
211 }
212 } catch (Throwable e) {
213 if (debug) {
214 System.out.println (e);
215 }
216 try {close(); } catch (IOException e1) {}
217 }
218 }
219
220 void doProxy(String dest, byte[] buf, int p, String cmdLine)
221 throws IOException
222 {
223 try {
224 URI uri = new URI(dest);
225 if (!uri.isAbsolute()) {
226 throw new IOException("request URI not absolute");
227 }
228 dest = uri.getAuthority();
229 // now extract the path from the URI and recreate the cmd line
230 int sp = cmdLine.indexOf(' ');
231 String method = cmdLine.substring(0, sp);
232 cmdLine = method + " " + uri.getPath() + " HTTP/1.1";
233 int x = cmdLine.length() - 1;
234 int i = p;
235 while (x >=0) {
236 buf[i--] = (byte)cmdLine.charAt(x--);
237 }
238 i++;
239
240 commonInit(dest, 80);
241 OutputStream sout;
242 synchronized (this) {
243 if (closing) return;
244 sout = serverOut;
245 }
246 // might fail if we're closing but we don't care.
247 sout.write(buf, i, buf.length-i);
248 proxyCommon();
249
250 } catch (URISyntaxException e) {
251 throw new IOException(e);
252 }
253 }
254
255 synchronized void commonInit(String dest, int defaultPort) throws IOException {
256 if (closing) return;
257 int port;
258 String[] hostport = dest.split(":");
259 if (hostport.length == 1) {
260 port = defaultPort;
261 } else {
262 port = Integer.parseInt(hostport[1]);
263 }
264 if (debug) System.out.printf("Server: (%s/%d)\n", hostport[0], port);
265 serverSocket = new Socket(hostport[0], port);
266 serverOut = serverSocket.getOutputStream();
267
268 serverIn = new BufferedInputStream(serverSocket.getInputStream());
269 }
270
271 synchronized void proxyCommon() throws IOException {
272 if (closing) return;
273 out = new Thread(() -> {
274 try {
275 byte[] bb = new byte[8000];
276 int n;
277 while ((n = clientIn.read(bb)) != -1) {
278 serverOut.write(bb, 0, n);
279 }
280 closing = true;
281 serverSocket.close();
282 clientSocket.close();
283 } catch (IOException e) {
284 if (debug) {
285 System.out.println (e);
286 }
287 }
288 });
289 in = new Thread(() -> {
290 try {
291 byte[] bb = new byte[8000];
292 int n;
293 while ((n = serverIn.read(bb)) != -1) {
294 clientOut.write(bb, 0, n);
295 }
296 closing = true;
297 serverSocket.close();
298 clientSocket.close();
299 } catch (IOException e) {
300 if (debug) {
301 System.out.println(e);
302 e.printStackTrace();
303 }
304 }
305 });
306 out.setName("Proxy-outbound");
307 out.setDaemon(true);
308 in.setDaemon(true);
309 in.setName("Proxy-inbound");
310 out.start();
311 in.start();
312 }
313
314 void doTunnel(String dest) throws IOException {
315 if (closing) return; // no need to go further.
316 commonInit(dest, 443);
317 // might fail if we're closing, but we don't care.
318 clientOut.write("HTTP/1.1 200 OK\r\n\r\n".getBytes());
319 proxyCommon();
320 }
321 }
322
323 public static void main(String[] args) throws Exception {
324 int port = Integer.parseInt(args[0]);
325 boolean debug = args.length > 1 && args[1].equals("-debug");
326 System.out.println("Debugging : " + debug);
327 ProxyServer ps = new ProxyServer(port, debug);
328 System.out.println("Proxy server listening on port " + ps.getPort());
329 while (true) {
330 Thread.sleep(5000);
331 }
332 }
333 }