1 const char gateway_rcs[] = "$Id: gateway.c,v 1.18 2006/07/18 14:48:46 david__schmidt Exp $";
2 /*********************************************************************
4 * File : $Source: /cvsroot/ijbswa/current/gateway.c,v $
6 * Purpose : Contains functions to connect to a server, possibly
7 * using a "forwarder" (i.e. HTTP proxy and/or a SOCKS4
10 * Copyright : Written by and Copyright (C) 2001-2007 the SourceForge
11 * Privoxy team. http://www.privoxy.org/
13 * Based on the Internet Junkbuster originally written
14 * by and Copyright (C) 1997 Anonymous Coders and
15 * Junkbusters Corporation. http://www.junkbusters.com
17 * This program is free software; you can redistribute it
18 * and/or modify it under the terms of the GNU General
19 * Public License as published by the Free Software
20 * Foundation; either version 2 of the License, or (at
21 * your option) any later version.
23 * This program is distributed in the hope that it will
24 * be useful, but WITHOUT ANY WARRANTY; without even the
25 * implied warranty of MERCHANTABILITY or FITNESS FOR A
26 * PARTICULAR PURPOSE. See the GNU General Public
27 * License for more details.
29 * The GNU General Public License should be included with
30 * this file. If not, you can view it at
31 * http://www.gnu.org/copyleft/gpl.html
32 * or write to the Free Software Foundation, Inc., 59
33 * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
37 * Revision 1.18 2006/07/18 14:48:46 david__schmidt
38 * Reorganizing the repository: swapping out what was HEAD (the old 3.1 branch)
39 * with what was really the latest development (the v_3_0_branch branch)
41 * Revision 1.16 2002/05/12 21:36:29 jongfoster
42 * Correcting function comments
44 * Revision 1.15 2002/03/26 22:29:54 swa
45 * we have a new homepage!
47 * Revision 1.14 2002/03/24 13:25:43 swa
48 * name change related issues
50 * Revision 1.13 2002/03/13 00:29:59 jongfoster
53 * Revision 1.12 2002/03/09 20:03:52 jongfoster
54 * - Making various functions return int rather than size_t.
55 * (Undoing a recent change). Since size_t is unsigned on
56 * Windows, functions like read_socket that return -1 on
57 * error cannot return a size_t.
59 * THIS WAS A MAJOR BUG - it caused frequent, unpredictable
60 * crashes, and also frequently caused JB to jump to 100%
61 * CPU and stay there. (Because it thought it had just
62 * read ((unsigned)-1) == 4Gb of data...)
64 * - The signature of write_socket has changed, it now simply
65 * returns success=0/failure=nonzero.
67 * - Trying to get rid of a few warnings --with-debug on
68 * Windows, I've introduced a new type "jb_socket". This is
69 * used for the socket file descriptors. On Windows, this
70 * is SOCKET (a typedef for unsigned). Everywhere else, it's
71 * an int. The error value can't be -1 any more, so it's
72 * now JB_INVALID_SOCKET (which is -1 on UNIX, and in
73 * Windows it maps to the #define INVALID_SOCKET.)
75 * - The signature of bind_port has changed.
77 * Revision 1.11 2002/03/08 17:46:04 jongfoster
78 * Fixing int/size_t warnings
80 * Revision 1.10 2002/03/07 03:50:19 oes
81 * - Improved handling of failed DNS lookups
82 * - Fixed compiler warnings
84 * Revision 1.9 2001/10/25 03:40:48 david__schmidt
85 * Change in porting tactics: OS/2's EMX porting layer doesn't allow multiple
86 * threads to call select() simultaneously. So, it's time to do a real, live,
87 * native OS/2 port. See defines for __EMX__ (the porting layer) vs. __OS2__
88 * (native). Both versions will work, but using __OS2__ offers multi-threading.
90 * Revision 1.8 2001/09/13 20:10:12 jongfoster
91 * Fixing missing #include under Windows
93 * Revision 1.7 2001/09/12 17:58:26 steudten
95 * add #include <string.h>
97 * Revision 1.6 2001/09/10 10:41:16 oes
100 * Revision 1.5 2001/07/29 18:47:57 jongfoster
101 * Adding missing #include project.h
103 * Revision 1.4 2001/07/24 12:47:06 oes
104 * Applied BeOS support update by Eugenia
106 * Revision 1.3 2001/06/09 10:55:28 jongfoster
107 * Changing BUFSIZ ==> BUFFER_SIZE
109 * Revision 1.2 2001/06/07 23:11:38 jongfoster
110 * Removing gateways[] list - no longer used.
111 * Replacing function pointer in struct gateway with a directly
112 * called function forwarded_connect(), which can do the common
113 * task of deciding whether to connect to the web server or HTTP
115 * Replacing struct gateway with struct forward_spec
116 * Fixing bug with SOCKS4A and HTTP proxy server in combination.
117 * It was a bug which led to the connection being made to the web
118 * server rather than the HTTP proxy, and also a buffer overrun.
120 * Revision 1.1.1.1 2001/05/15 13:58:54 oes
121 * Initial import of version 2.9.3 source tree
124 *********************************************************************/
130 #include <sys/types.h>
133 #include <netinet/in.h>
140 #include <winsock2.h>
141 #endif /* def _WIN32 */
145 #endif /* def __BEOS__ */
149 #endif /* def __OS2__ */
154 #include "jbsockets.h"
157 const char gateway_h_rcs[] = GATEWAY_H_VERSION;
159 static jb_socket socks4_connect(const struct forward_spec * fwd,
160 const char * target_host,
162 struct client_state *csp);
165 #define SOCKS_REQUEST_GRANTED 90
166 #define SOCKS_REQUEST_REJECT 91
167 #define SOCKS_REQUEST_IDENT_FAILED 92
168 #define SOCKS_REQUEST_IDENT_CONFLICT 93
170 /* structure of a socks client operation */
172 unsigned char vn; /* socks version number */
173 unsigned char cd; /* command code */
174 unsigned char dstport[2]; /* destination port */
175 unsigned char dstip[4]; /* destination address */
176 unsigned char userid; /* first byte of userid */
177 /* more bytes of the userid follow, terminated by a NULL */
180 /* structure of a socks server reply */
182 unsigned char vn; /* socks version number */
183 unsigned char cd; /* command code */
184 unsigned char dstport[2]; /* destination port */
185 unsigned char dstip[4]; /* destination address */
188 static const char socks_userid[] = "anonymous";
191 /*********************************************************************
193 * Function : forwarded_connect
195 * Description : Connect to a specified web server, possibly via
196 * a HTTP proxy and/or a SOCKS proxy.
199 * 1 : fwd = the proxies to use when connecting.
200 * 2 : http = the http request and apropos headers
201 * 3 : csp = Current client state (buffers, headers, etc...)
203 * Returns : JB_INVALID_SOCKET => failure, else it is the socket file descriptor.
205 *********************************************************************/
206 jb_socket forwarded_connect(const struct forward_spec * fwd,
207 struct http_request *http,
208 struct client_state *csp)
210 const char * dest_host;
213 /* Figure out if we need to connect to the web server or a HTTP proxy. */
214 if (fwd->forward_host)
217 dest_host = fwd->forward_host;
218 dest_port = fwd->forward_port;
223 dest_host = http->host;
224 dest_port = http->port;
227 /* Connect, maybe using a SOCKS proxy */
231 return (connect_to(dest_host, dest_port, csp));
235 return (socks4_connect(fwd, dest_host, dest_port, csp));
238 /* Should never get here */
239 log_error(LOG_LEVEL_FATAL, "SOCKS4 impossible internal error - bad SOCKS type.");
241 return(JB_INVALID_SOCKET);
246 /*********************************************************************
248 * Function : socks4_connect
250 * Description : Connect to the SOCKS server, and connect through
251 * it to the specified server. This handles
252 * all the SOCKS negotiation, and returns a file
253 * descriptor for a socket which can be treated as a
254 * normal (non-SOCKS) socket.
256 * Logged error messages are saved to csp->error_message
257 * and later reused by error_response() for the CGI
258 * message. strdup allocation failures are handled there.
261 * 1 : fwd = Specifies the SOCKS proxy to use.
262 * 2 : target_host = The final server to connect to.
263 * 3 : target_port = The final port to connect to.
264 * 4 : csp = Current client state (buffers, headers, etc...)
266 * Returns : JB_INVALID_SOCKET => failure, else a socket file descriptor.
268 *********************************************************************/
269 static jb_socket socks4_connect(const struct forward_spec * fwd,
270 const char * target_host,
272 struct client_state *csp)
275 char cbuf[BUFFER_SIZE];
276 char sbuf[BUFFER_SIZE];
277 struct socks_op *c = (struct socks_op *)cbuf;
278 struct socks_reply *s = (struct socks_reply *)sbuf;
285 if ((fwd->gateway_host == NULL) || (*fwd->gateway_host == '\0'))
287 /* XXX: Shouldn't the config file parser prevent this? */
288 errstr = "NULL gateway host specified.";
292 if (fwd->gateway_port <= 0)
294 errstr = "invalid gateway port specified.";
300 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
301 csp->error_message = strdup(errstr);
303 return(JB_INVALID_SOCKET);
306 /* build a socks request for connection to the web server */
308 strcpy((char *)&(c->userid), socks_userid);
310 csiz = sizeof(*c) + sizeof(socks_userid) - 1;
315 web_server_addr = htonl(resolve_hostname_to_ip(target_host));
316 if (web_server_addr == INADDR_NONE)
318 errstr = "could not resolve target host";
319 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s %s", errstr, target_host);
324 web_server_addr = 0x00000001;
325 n = csiz + strlen(target_host) + 1;
326 if (n > sizeof(cbuf))
329 errstr = "buffer cbuf too small.";
330 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
335 strcpy(cbuf + csiz, target_host);
340 /* Should never get here */
341 log_error(LOG_LEVEL_FATAL,
342 "socks4_connect: SOCKS4 impossible internal error - bad SOCKS type.");
348 csp->error_message = strdup(errstr);
349 return(JB_INVALID_SOCKET);
354 /* XXX: these casts surpress gcc43 warnings, but are they correct? */
355 c->dstport[0] = (unsigned char)((target_port >> 8 ) & 0xff);
356 c->dstport[1] = (unsigned char)((target_port ) & 0xff);
357 c->dstip[0] = (unsigned char)((web_server_addr >> 24 ) & 0xff);
358 c->dstip[1] = (unsigned char)((web_server_addr >> 16 ) & 0xff);
359 c->dstip[2] = (unsigned char)((web_server_addr >> 8 ) & 0xff);
360 c->dstip[3] = (unsigned char)((web_server_addr ) & 0xff);
362 /* pass the request to the socks server */
363 sfd = connect_to(fwd->gateway_host, fwd->gateway_port, csp);
365 if (sfd == JB_INVALID_SOCKET)
368 * XXX: connect_to could fill in the exact reason.
369 * Most likely resolving the IP of the forwarder failed.
371 errstr = "connect_to failed: see logfile for details";
374 else if (write_socket(sfd, (char *)c, csiz))
376 errstr = "SOCKS4 negotiation write failed.";
377 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
381 else if (read_socket(sfd, sbuf, sizeof(sbuf)) != sizeof(*s))
383 errstr = "SOCKS4 negotiation read failed.";
384 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
391 csp->error_message = strdup(errstr);
392 return(JB_INVALID_SOCKET);
397 case SOCKS_REQUEST_GRANTED:
400 case SOCKS_REQUEST_REJECT:
401 errstr = "SOCKS request rejected or failed.";
404 case SOCKS_REQUEST_IDENT_FAILED:
405 errstr = "SOCKS request rejected because "
406 "SOCKS server cannot connect to identd on the client.";
409 case SOCKS_REQUEST_IDENT_CONFLICT:
410 errstr = "SOCKS request rejected because "
411 "the client program and identd report "
412 "different user-ids.";
417 snprintf(cbuf, sizeof(cbuf),
418 "SOCKS request rejected for reason code %d.", s->cd);
422 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
423 csp->error_message = strdup(errstr);
426 return(JB_INVALID_SOCKET);