1 const char gateway_rcs[] = "$Id: gateway.c,v 1.20 2007/05/14 10:23:48 fabiankeil 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 1.20 2007/05/14 10:23:48 fabiankeil
38 * - Use strlcpy() instead of strcpy().
39 * - Use the same buffer for socks requests and socks responses.
40 * - Fix bogus warning about web_server_addr being used uninitialized.
42 * Revision 1.19 2007/01/25 14:09:45 fabiankeil
43 * - Save errors in socks4_connect() to csp->error_message.
44 * - Silence some gcc43 warnings, hopefully the right way.
46 * Revision 1.18 2006/07/18 14:48:46 david__schmidt
47 * Reorganizing the repository: swapping out what was HEAD (the old 3.1 branch)
48 * with what was really the latest development (the v_3_0_branch branch)
50 * Revision 1.16 2002/05/12 21:36:29 jongfoster
51 * Correcting function comments
53 * Revision 1.15 2002/03/26 22:29:54 swa
54 * we have a new homepage!
56 * Revision 1.14 2002/03/24 13:25:43 swa
57 * name change related issues
59 * Revision 1.13 2002/03/13 00:29:59 jongfoster
62 * Revision 1.12 2002/03/09 20:03:52 jongfoster
63 * - Making various functions return int rather than size_t.
64 * (Undoing a recent change). Since size_t is unsigned on
65 * Windows, functions like read_socket that return -1 on
66 * error cannot return a size_t.
68 * THIS WAS A MAJOR BUG - it caused frequent, unpredictable
69 * crashes, and also frequently caused JB to jump to 100%
70 * CPU and stay there. (Because it thought it had just
71 * read ((unsigned)-1) == 4Gb of data...)
73 * - The signature of write_socket has changed, it now simply
74 * returns success=0/failure=nonzero.
76 * - Trying to get rid of a few warnings --with-debug on
77 * Windows, I've introduced a new type "jb_socket". This is
78 * used for the socket file descriptors. On Windows, this
79 * is SOCKET (a typedef for unsigned). Everywhere else, it's
80 * an int. The error value can't be -1 any more, so it's
81 * now JB_INVALID_SOCKET (which is -1 on UNIX, and in
82 * Windows it maps to the #define INVALID_SOCKET.)
84 * - The signature of bind_port has changed.
86 * Revision 1.11 2002/03/08 17:46:04 jongfoster
87 * Fixing int/size_t warnings
89 * Revision 1.10 2002/03/07 03:50:19 oes
90 * - Improved handling of failed DNS lookups
91 * - Fixed compiler warnings
93 * Revision 1.9 2001/10/25 03:40:48 david__schmidt
94 * Change in porting tactics: OS/2's EMX porting layer doesn't allow multiple
95 * threads to call select() simultaneously. So, it's time to do a real, live,
96 * native OS/2 port. See defines for __EMX__ (the porting layer) vs. __OS2__
97 * (native). Both versions will work, but using __OS2__ offers multi-threading.
99 * Revision 1.8 2001/09/13 20:10:12 jongfoster
100 * Fixing missing #include under Windows
102 * Revision 1.7 2001/09/12 17:58:26 steudten
104 * add #include <string.h>
106 * Revision 1.6 2001/09/10 10:41:16 oes
107 * Added #include in.h
109 * Revision 1.5 2001/07/29 18:47:57 jongfoster
110 * Adding missing #include project.h
112 * Revision 1.4 2001/07/24 12:47:06 oes
113 * Applied BeOS support update by Eugenia
115 * Revision 1.3 2001/06/09 10:55:28 jongfoster
116 * Changing BUFSIZ ==> BUFFER_SIZE
118 * Revision 1.2 2001/06/07 23:11:38 jongfoster
119 * Removing gateways[] list - no longer used.
120 * Replacing function pointer in struct gateway with a directly
121 * called function forwarded_connect(), which can do the common
122 * task of deciding whether to connect to the web server or HTTP
124 * Replacing struct gateway with struct forward_spec
125 * Fixing bug with SOCKS4A and HTTP proxy server in combination.
126 * It was a bug which led to the connection being made to the web
127 * server rather than the HTTP proxy, and also a buffer overrun.
129 * Revision 1.1.1.1 2001/05/15 13:58:54 oes
130 * Initial import of version 2.9.3 source tree
133 *********************************************************************/
139 #include <sys/types.h>
142 #include <netinet/in.h>
150 #include <winsock2.h>
151 #endif /* def _WIN32 */
155 #endif /* def __BEOS__ */
159 #endif /* def __OS2__ */
164 #include "jbsockets.h"
166 #include "miscutil.h"
168 const char gateway_h_rcs[] = GATEWAY_H_VERSION;
170 static jb_socket socks4_connect(const struct forward_spec * fwd,
171 const char * target_host,
173 struct client_state *csp);
176 #define SOCKS_REQUEST_GRANTED 90
177 #define SOCKS_REQUEST_REJECT 91
178 #define SOCKS_REQUEST_IDENT_FAILED 92
179 #define SOCKS_REQUEST_IDENT_CONFLICT 93
181 /* structure of a socks client operation */
183 unsigned char vn; /* socks version number */
184 unsigned char cd; /* command code */
185 unsigned char dstport[2]; /* destination port */
186 unsigned char dstip[4]; /* destination address */
187 char userid; /* first byte of userid */
188 char padding[3]; /* make sure sizeof(struct socks_op) is endian-independent. */
189 /* more bytes of the userid follow, terminated by a NULL */
192 /* structure of a socks server reply */
194 unsigned char vn; /* socks version number */
195 unsigned char cd; /* command code */
196 unsigned char dstport[2]; /* destination port */
197 unsigned char dstip[4]; /* destination address */
200 static const char socks_userid[] = "anonymous";
203 /*********************************************************************
205 * Function : forwarded_connect
207 * Description : Connect to a specified web server, possibly via
208 * a HTTP proxy and/or a SOCKS proxy.
211 * 1 : fwd = the proxies to use when connecting.
212 * 2 : http = the http request and apropos headers
213 * 3 : csp = Current client state (buffers, headers, etc...)
215 * Returns : JB_INVALID_SOCKET => failure, else it is the socket file descriptor.
217 *********************************************************************/
218 jb_socket forwarded_connect(const struct forward_spec * fwd,
219 struct http_request *http,
220 struct client_state *csp)
222 const char * dest_host;
225 /* Figure out if we need to connect to the web server or a HTTP proxy. */
226 if (fwd->forward_host)
229 dest_host = fwd->forward_host;
230 dest_port = fwd->forward_port;
235 dest_host = http->host;
236 dest_port = http->port;
239 /* Connect, maybe using a SOCKS proxy */
243 return (connect_to(dest_host, dest_port, csp));
247 return (socks4_connect(fwd, dest_host, dest_port, csp));
250 /* Should never get here */
251 log_error(LOG_LEVEL_FATAL, "SOCKS4 impossible internal error - bad SOCKS type.");
253 return(JB_INVALID_SOCKET);
258 /*********************************************************************
260 * Function : socks4_connect
262 * Description : Connect to the SOCKS server, and connect through
263 * it to the specified server. This handles
264 * all the SOCKS negotiation, and returns a file
265 * descriptor for a socket which can be treated as a
266 * normal (non-SOCKS) socket.
268 * Logged error messages are saved to csp->error_message
269 * and later reused by error_response() for the CGI
270 * message. strdup allocation failures are handled there.
273 * 1 : fwd = Specifies the SOCKS proxy to use.
274 * 2 : target_host = The final server to connect to.
275 * 3 : target_port = The final port to connect to.
276 * 4 : csp = Current client state (buffers, headers, etc...)
278 * Returns : JB_INVALID_SOCKET => failure, else a socket file descriptor.
280 *********************************************************************/
281 static jb_socket socks4_connect(const struct forward_spec * fwd,
282 const char * target_host,
284 struct client_state *csp)
287 char buf[BUFFER_SIZE];
288 struct socks_op *c = (struct socks_op *)buf;
289 struct socks_reply *s = (struct socks_reply *)buf;
296 if ((fwd->gateway_host == NULL) || (*fwd->gateway_host == '\0'))
298 /* XXX: Shouldn't the config file parser prevent this? */
299 errstr = "NULL gateway host specified.";
303 if (fwd->gateway_port <= 0)
305 errstr = "invalid gateway port specified.";
311 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
312 csp->error_message = strdup(errstr);
314 return(JB_INVALID_SOCKET);
317 /* build a socks request for connection to the web server */
319 strlcpy(&(c->userid), socks_userid, sizeof(buf) - sizeof(struct socks_op));
321 csiz = sizeof(*c) + sizeof(socks_userid) - sizeof(c->userid) - sizeof(c->padding);
326 web_server_addr = htonl(resolve_hostname_to_ip(target_host));
327 if (web_server_addr == INADDR_NONE)
329 errstr = "could not resolve target host";
330 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s %s", errstr, target_host);
335 web_server_addr = 0x00000001;
336 n = csiz + strlen(target_host) + 1;
340 errstr = "buffer cbuf too small.";
341 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
346 strlcpy(buf + csiz, target_host, sizeof(buf) - sizeof(struct socks_op) - csiz);
348 * What we forward to the socks4a server should have the
349 * size of socks_op, plus the length of the userid plus
350 * its \0 byte (which we don't have to add because the
351 * first byte of the userid is counted twice as it's also
352 * part of sock_op) minus the padding bytes (which are part
353 * of the userid as well), plus the length of the target_host
354 * (which is stored csiz bytes after the beginning of the buffer),
355 * plus another \0 byte.
357 assert(n == sizeof(struct socks_op) + strlen(&(c->userid)) - sizeof(c->padding) + strlen(buf + csiz) + 1);
362 /* Should never get here */
363 log_error(LOG_LEVEL_FATAL,
364 "socks4_connect: SOCKS4 impossible internal error - bad SOCKS type.");
366 return(JB_INVALID_SOCKET);
371 csp->error_message = strdup(errstr);
372 return(JB_INVALID_SOCKET);
377 c->dstport[0] = (unsigned char)((target_port >> 8 ) & 0xff);
378 c->dstport[1] = (unsigned char)((target_port ) & 0xff);
379 c->dstip[0] = (unsigned char)((web_server_addr >> 24 ) & 0xff);
380 c->dstip[1] = (unsigned char)((web_server_addr >> 16 ) & 0xff);
381 c->dstip[2] = (unsigned char)((web_server_addr >> 8 ) & 0xff);
382 c->dstip[3] = (unsigned char)((web_server_addr ) & 0xff);
384 /* pass the request to the socks server */
385 sfd = connect_to(fwd->gateway_host, fwd->gateway_port, csp);
387 if (sfd == JB_INVALID_SOCKET)
390 * XXX: connect_to should fill in the exact reason.
391 * Most likely resolving the IP of the forwarder failed.
393 errstr = "connect_to failed: see logfile for details";
396 else if (write_socket(sfd, (char *)c, csiz))
398 errstr = "SOCKS4 negotiation write failed.";
399 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
403 else if (read_socket(sfd, buf, sizeof(buf)) != sizeof(*s))
405 errstr = "SOCKS4 negotiation read failed.";
406 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
413 csp->error_message = strdup(errstr);
414 return(JB_INVALID_SOCKET);
419 case SOCKS_REQUEST_GRANTED:
422 case SOCKS_REQUEST_REJECT:
423 errstr = "SOCKS request rejected or failed.";
426 case SOCKS_REQUEST_IDENT_FAILED:
427 errstr = "SOCKS request rejected because "
428 "SOCKS server cannot connect to identd on the client.";
431 case SOCKS_REQUEST_IDENT_CONFLICT:
432 errstr = "SOCKS request rejected because "
433 "the client program and identd report "
434 "different user-ids.";
439 snprintf(buf, sizeof(buf),
440 "SOCKS request rejected for reason code %d.", s->cd);
444 log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
445 csp->error_message = strdup(errstr);
448 return(JB_INVALID_SOCKET);