2 * Network proxy abstraction in PuTTY
4 * A proxy layer, if necessary, wedges itself between the network
5 * code and the higher level backend.
12 #define DEFINE_PLUG_METHOD_MACROS
18 * Call this when proxy negotiation is complete, so that this
19 * socket can begin working normally.
21 void proxy_activate (Proxy_Socket p)
25 long output_before, output_after;
27 p->state = PROXY_STATE_ACTIVE;
29 /* we want to ignore new receive events until we have sent
30 * all of our buffered receive data.
32 sk_set_frozen(p->sub_socket, 1);
34 /* how many bytes of output have we buffered? */
35 output_before = bufchain_size(&p->pending_oob_output_data) +
36 bufchain_size(&p->pending_output_data);
37 /* and keep track of how many bytes do not get sent. */
40 /* send buffered OOB writes */
41 while (bufchain_size(&p->pending_oob_output_data) > 0) {
42 bufchain_prefix(&p->pending_oob_output_data, &data, &len);
43 output_after += sk_write_oob(p->sub_socket, data, len);
44 bufchain_consume(&p->pending_oob_output_data, len);
47 /* send buffered normal writes */
48 while (bufchain_size(&p->pending_output_data) > 0) {
49 bufchain_prefix(&p->pending_output_data, &data, &len);
50 output_after += sk_write(p->sub_socket, data, len);
51 bufchain_consume(&p->pending_output_data, len);
54 /* if we managed to send any data, let the higher levels know. */
55 if (output_after < output_before)
56 plug_sent(p->plug, output_after);
58 /* if we were asked to flush the output during
59 * the proxy negotiation process, do so now.
61 if (p->pending_flush) sk_flush(p->sub_socket);
63 /* if the backend wanted the socket unfrozen, try to unfreeze.
64 * our set_frozen handler will flush buffered receive data before
65 * unfreezing the actual underlying socket.
68 sk_set_frozen((Socket)p, 0);
71 /* basic proxy socket functions */
73 static Plug sk_proxy_plug (Socket s, Plug p)
75 Proxy_Socket ps = (Proxy_Socket) s;
82 static void sk_proxy_close (Socket s)
84 Proxy_Socket ps = (Proxy_Socket) s;
86 sk_close(ps->sub_socket);
90 static int sk_proxy_write (Socket s, char *data, int len)
92 Proxy_Socket ps = (Proxy_Socket) s;
94 if (ps->state != PROXY_STATE_ACTIVE) {
95 bufchain_add(&ps->pending_output_data, data, len);
96 return bufchain_size(&ps->pending_output_data);
98 return sk_write(ps->sub_socket, data, len);
101 static int sk_proxy_write_oob (Socket s, char *data, int len)
103 Proxy_Socket ps = (Proxy_Socket) s;
105 if (ps->state != PROXY_STATE_ACTIVE) {
106 bufchain_clear(&ps->pending_output_data);
107 bufchain_clear(&ps->pending_oob_output_data);
108 bufchain_add(&ps->pending_oob_output_data, data, len);
111 return sk_write_oob(ps->sub_socket, data, len);
114 static void sk_proxy_flush (Socket s)
116 Proxy_Socket ps = (Proxy_Socket) s;
118 if (ps->state != PROXY_STATE_ACTIVE) {
119 ps->pending_flush = 1;
122 sk_flush(ps->sub_socket);
125 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
127 Proxy_Socket ps = (Proxy_Socket) s;
128 sk_set_private_ptr(ps->sub_socket, ptr);
131 static void * sk_proxy_get_private_ptr (Socket s)
133 Proxy_Socket ps = (Proxy_Socket) s;
134 return sk_get_private_ptr(ps->sub_socket);
137 static void sk_proxy_set_frozen (Socket s, int is_frozen)
139 Proxy_Socket ps = (Proxy_Socket) s;
141 if (ps->state != PROXY_STATE_ACTIVE) {
142 ps->freeze = is_frozen;
146 /* handle any remaining buffered recv data first */
147 if (bufchain_size(&ps->pending_input_data) > 0) {
148 ps->freeze = is_frozen;
150 /* loop while we still have buffered data, and while we are
151 * unfrozen. the plug_receive call in the loop could result
152 * in a call back into this function refreezing the socket,
153 * so we have to check each time.
155 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
158 bufchain_prefix(&ps->pending_input_data, &data, &len);
159 plug_receive(ps->plug, 0, data, len);
160 bufchain_consume(&ps->pending_input_data, len);
163 /* if we're still frozen, we'll have to wait for another
164 * call from the backend to finish unbuffering the data.
166 if (ps->freeze) return;
169 sk_set_frozen(ps->sub_socket, is_frozen);
172 static char * sk_proxy_socket_error (Socket s)
174 Proxy_Socket ps = (Proxy_Socket) s;
175 if (ps->error != NULL || ps->sub_socket == NULL) {
178 return sk_socket_error(ps->sub_socket);
181 /* basic proxy plug functions */
183 static int plug_proxy_closing (Plug p, char *error_msg,
184 int error_code, int calling_back)
186 Proxy_Plug pp = (Proxy_Plug) p;
187 Proxy_Socket ps = pp->proxy_socket;
189 if (ps->state != PROXY_STATE_ACTIVE) {
190 ps->closing_error_msg = error_msg;
191 ps->closing_error_code = error_code;
192 ps->closing_calling_back = calling_back;
193 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
195 return plug_closing(ps->plug, error_msg,
196 error_code, calling_back);
199 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
201 Proxy_Plug pp = (Proxy_Plug) p;
202 Proxy_Socket ps = pp->proxy_socket;
204 if (ps->state != PROXY_STATE_ACTIVE) {
205 /* we will lose the urgentness of this data, but since most,
206 * if not all, of this data will be consumed by the negotiation
207 * process, hopefully it won't affect the protocol above us
209 bufchain_add(&ps->pending_input_data, data, len);
210 ps->receive_urgent = urgent;
211 ps->receive_data = data;
212 ps->receive_len = len;
213 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
215 return plug_receive(ps->plug, urgent, data, len);
218 static void plug_proxy_sent (Plug p, int bufsize)
220 Proxy_Plug pp = (Proxy_Plug) p;
221 Proxy_Socket ps = pp->proxy_socket;
223 if (ps->state != PROXY_STATE_ACTIVE) {
224 ps->sent_bufsize = bufsize;
225 ps->negotiate(ps, PROXY_CHANGE_SENT);
228 plug_sent(ps->plug, bufsize);
231 static int plug_proxy_accepting (Plug p, void *sock)
233 Proxy_Plug pp = (Proxy_Plug) p;
234 Proxy_Socket ps = pp->proxy_socket;
236 if (ps->state != PROXY_STATE_ACTIVE) {
237 ps->accepting_sock = sock;
238 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
240 return plug_accepting(ps->plug, sock);
243 static int proxy_for_destination (SockAddr addr, char * hostname, int port)
247 int hostip_len, hostname_len;
251 * Check the host name and IP against the hard-coded
252 * representations of `localhost'.
254 if (!cfg.even_proxy_localhost &&
255 (sk_hostname_is_local(hostname) || sk_address_is_local(addr)))
256 return 0; /* do not proxy */
258 /* we want a string representation of the IP address for comparisons */
259 sk_getaddr(addr, hostip, 64);
261 hostip_len = strlen(hostip);
262 hostname_len = strlen(hostname);
264 exclude_list = cfg.proxy_exclude_list;
266 /* now parse the exclude list, and see if either our IP
267 * or hostname matches anything in it.
270 while (exclude_list[s]) {
271 while (exclude_list[s] &&
272 (isspace(exclude_list[s]) ||
273 exclude_list[s] == ',')) s++;
275 if (!exclude_list[s]) break;
279 while (exclude_list[e] &&
280 (isalnum(exclude_list[e]) ||
281 exclude_list[e] == '-' ||
282 exclude_list[e] == '.' ||
283 exclude_list[e] == '*')) e++;
285 if (exclude_list[s] == '*') {
286 /* wildcard at beginning of entry */
288 if (strnicmp(hostip + hostip_len - (e - s - 1),
289 exclude_list + s + 1, e - s - 1) == 0 ||
290 strnicmp(hostname + hostname_len - (e - s - 1),
291 exclude_list + s + 1, e - s - 1) == 0)
292 return 0; /* IP/hostname range excluded. do not use proxy. */
294 } else if (exclude_list[e-1] == '*') {
295 /* wildcard at end of entry */
297 if (strnicmp(hostip, exclude_list + s, e - s - 1) == 0 ||
298 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
299 return 0; /* IP/hostname range excluded. do not use proxy. */
302 /* no wildcard at either end, so let's try an absolute
303 * match (ie. a specific IP)
306 if (stricmp(hostip, exclude_list + s) == 0)
307 return 0; /* IP/hostname excluded. do not use proxy. */
308 if (stricmp(hostname, exclude_list + s) == 0)
309 return 0; /* IP/hostname excluded. do not use proxy. */
315 /* no matches in the exclude list, so use the proxy */
319 Socket new_connection(SockAddr addr, char *hostname,
320 int port, int privport,
321 int oobinline, int nodelay, Plug plug)
323 static const struct socket_function_table socket_fn_table = {
329 sk_proxy_set_private_ptr,
330 sk_proxy_get_private_ptr,
332 sk_proxy_socket_error
335 static const struct plug_function_table plug_fn_table = {
342 if (cfg.proxy_type != PROXY_NONE &&
343 proxy_for_destination(addr, hostname, port))
348 char *proxy_canonical_name, *err;
350 ret = smalloc(sizeof(struct Socket_proxy_tag));
351 ret->fn = &socket_fn_table;
353 ret->remote_addr = addr;
354 ret->remote_port = port;
357 ret->pending_flush = 0;
360 bufchain_init(&ret->pending_input_data);
361 bufchain_init(&ret->pending_output_data);
362 bufchain_init(&ret->pending_oob_output_data);
364 ret->sub_socket = NULL;
365 ret->state = PROXY_STATE_NEW;
366 ret->negotiate = NULL;
368 if (cfg.proxy_type == PROXY_HTTP) {
369 ret->negotiate = proxy_http_negotiate;
370 } else if (cfg.proxy_type == PROXY_SOCKS) {
371 if (cfg.proxy_socks_version == 4)
372 ret->negotiate = proxy_socks4_negotiate;
374 ret->negotiate = proxy_socks5_negotiate;
375 } else if (cfg.proxy_type == PROXY_TELNET) {
376 ret->negotiate = proxy_telnet_negotiate;
378 ret->error = "Proxy error: Unknown proxy method";
382 /* create the proxy plug to map calls from the actual
383 * socket into our proxy socket layer */
384 pplug = smalloc(sizeof(struct Plug_proxy_tag));
385 pplug->fn = &plug_fn_table;
386 pplug->proxy_socket = ret;
389 proxy_addr = sk_namelookup(cfg.proxy_host,
390 &proxy_canonical_name);
391 if ((err = sk_addr_error(proxy_addr))) {
392 ret->error = "Proxy error: Unable to resolve proxy host name";
395 sfree(proxy_canonical_name);
397 /* create the actual socket we will be using,
398 * connected to our proxy server and port.
400 ret->sub_socket = sk_new(proxy_addr, cfg.proxy_port,
402 nodelay, (Plug) pplug);
403 if (sk_socket_error(ret->sub_socket) != NULL)
406 sk_addr_free(proxy_addr);
408 /* start the proxy negotiation process... */
409 sk_set_frozen(ret->sub_socket, 0);
410 ret->negotiate(ret, PROXY_CHANGE_NEW);
415 /* no proxy, so just return the direct socket */
416 return sk_new(addr, port, privport, oobinline, nodelay, plug);
419 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only)
421 /* TODO: SOCKS (and potentially others) support inbound
422 * TODO: connections via the proxy. support them.
425 return sk_newlistener(srcaddr, port, plug, local_host_only);
428 /* ----------------------------------------------------------------------
429 * HTTP CONNECT proxy type.
432 static int get_line_end (char * data, int len)
438 if (data[off] == '\n') {
439 /* we have a newline */
442 /* is that the only thing on this line? */
443 if (off <= 2) return off;
445 /* if not, then there is the possibility that this header
446 * continues onto the next line, if it starts with a space
451 data[off+1] != ' ' &&
452 data[off+1] != '\t') return off;
454 /* the line does continue, so we have to keep going
455 * until we see an the header's "real" end of line.
466 int proxy_http_negotiate (Proxy_Socket p, int change)
468 if (p->state == PROXY_STATE_NEW) {
469 /* we are just beginning the proxy negotiate process,
470 * so we'll send off the initial bits of the request.
471 * for this proxy method, it's just a simple HTTP
476 sk_getaddr(p->remote_addr, dest, 64);
478 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
479 dest, p->remote_port, dest, p->remote_port);
480 sk_write(p->sub_socket, buf, strlen(buf));
483 if (cfg.proxy_username[0] || cfg.proxy_password[0]) {
484 char buf[sizeof(cfg.proxy_username)+sizeof(cfg.proxy_password)];
485 char buf2[sizeof(buf)*4/3 + 100];
487 sprintf(buf, "%s:%s", cfg.proxy_username, cfg.proxy_password);
489 sprintf(buf2, "Proxy-Authorization: basic ");
490 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
491 base64_encode_atom(buf+i, (len-i > 3 ? 3 : len-i), buf2+j);
492 strcpy(buf2+j, "\r\n");
493 sk_write(p->sub_socket, buf2, strlen(buf2));
496 sk_write(p->sub_socket, "\r\n", 2);
502 if (change == PROXY_CHANGE_CLOSING) {
503 /* if our proxy negotiation process involves closing and opening
504 * new sockets, then we would want to intercept this closing
505 * callback when we were expecting it. if we aren't anticipating
506 * a socket close, then some error must have occurred. we'll
507 * just pass those errors up to the backend.
509 return plug_closing(p->plug, p->closing_error_msg,
510 p->closing_error_code,
511 p->closing_calling_back);
514 if (change == PROXY_CHANGE_SENT) {
515 /* some (or all) of what we wrote to the proxy was sent.
516 * we don't do anything new, however, until we receive the
517 * proxy's response. we might want to set a timer so we can
518 * timeout the proxy negotiation after a while...
523 if (change == PROXY_CHANGE_ACCEPTING) {
524 /* we should _never_ see this, as we are using our socket to
525 * connect to a proxy, not accepting inbound connections.
526 * what should we do? close the socket with an appropriate
529 return plug_accepting(p->plug, p->accepting_sock);
532 if (change == PROXY_CHANGE_RECEIVE) {
533 /* we have received data from the underlying socket, which
534 * we'll need to parse, process, and respond to appropriately.
543 int min_ver, maj_ver, status;
545 /* get the status line */
546 len = bufchain_size(&p->pending_input_data);
547 assert(len > 0); /* or we wouldn't be here */
549 bufchain_fetch(&p->pending_input_data, data, len);
551 eol = get_line_end(data, len);
558 /* We can't rely on whether the %n incremented the sscanf return */
559 if (sscanf((char *)data, "HTTP/%i.%i %n",
560 &maj_ver, &min_ver, &status) < 2 || status == -1) {
561 plug_closing(p->plug, "Proxy error: HTTP response was absent",
562 PROXY_ERROR_GENERAL, 0);
567 /* remove the status line from the input buffer. */
568 bufchain_consume(&p->pending_input_data, eol);
569 if (data[status] != '2') {
573 while (eol > status &&
574 (data[eol-1] == '\r' || data[eol-1] == '\n'))
576 buf = dupprintf("Proxy error: %s", data+status);
577 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
590 /* get headers. we're done when we get a
591 * header of length 2, (ie. just "\r\n")
594 len = bufchain_size(&p->pending_input_data);
595 assert(len > 0); /* or we wouldn't be here */
598 bufchain_fetch(&p->pending_input_data, data, len);
600 eol = get_line_end(datap, len);
607 bufchain_consume(&p->pending_input_data, eol);
610 eol = get_line_end(datap, len);
615 bufchain_consume(&p->pending_input_data, 2);
617 /* proxy activate will have dealt with
618 * whatever is left of the buffer */
628 plug_closing(p->plug, "Proxy error: unexpected proxy error",
629 PROXY_ERROR_UNEXPECTED, 0);
633 /* ----------------------------------------------------------------------
637 /* SOCKS version 4 */
638 int proxy_socks4_negotiate (Proxy_Socket p, int change)
640 if (p->state == PROXY_CHANGE_NEW) {
643 * version number (1 byte) = 4
644 * command code (1 byte)
647 * dest. port (2 bytes) [network order]
648 * dest. address (4 bytes)
649 * user ID (variable length, null terminated string)
655 if (sk_addrtype(p->remote_addr) != ADDRTYPE_IPV4) {
656 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
657 " not support IPv6", PROXY_ERROR_GENERAL, 0);
661 length = strlen(cfg.proxy_username) + 9;
662 command = (char*) smalloc(length);
663 strcpy(command + 8, cfg.proxy_username);
665 command[0] = 4; /* version 4 */
666 command[1] = 1; /* CONNECT command */
669 command[2] = (char) (p->remote_port >> 8) & 0xff;
670 command[3] = (char) p->remote_port & 0xff;
673 sk_addrcopy(p->remote_addr, command + 4);
675 sk_write(p->sub_socket, command, length);
682 if (change == PROXY_CHANGE_CLOSING) {
683 /* if our proxy negotiation process involves closing and opening
684 * new sockets, then we would want to intercept this closing
685 * callback when we were expecting it. if we aren't anticipating
686 * a socket close, then some error must have occurred. we'll
687 * just pass those errors up to the backend.
689 return plug_closing(p->plug, p->closing_error_msg,
690 p->closing_error_code,
691 p->closing_calling_back);
694 if (change == PROXY_CHANGE_SENT) {
695 /* some (or all) of what we wrote to the proxy was sent.
696 * we don't do anything new, however, until we receive the
697 * proxy's response. we might want to set a timer so we can
698 * timeout the proxy negotiation after a while...
703 if (change == PROXY_CHANGE_ACCEPTING) {
704 /* we should _never_ see this, as we are using our socket to
705 * connect to a proxy, not accepting inbound connections.
706 * what should we do? close the socket with an appropriate
709 return plug_accepting(p->plug, p->accepting_sock);
712 if (change == PROXY_CHANGE_RECEIVE) {
713 /* we have received data from the underlying socket, which
714 * we'll need to parse, process, and respond to appropriately.
719 * version number (1 byte) = 4
720 * reply code (1 byte)
721 * 90 = request granted
722 * 91 = request rejected or failed
723 * 92 = request rejected due to lack of IDENTD on client
724 * 93 = request rejected due to difference in user ID
725 * (what we sent vs. what IDENTD said)
726 * dest. port (2 bytes)
727 * dest. address (4 bytes)
732 if (bufchain_size(&p->pending_input_data) < 8)
733 return 1; /* not got anything yet */
735 /* get the response */
736 bufchain_fetch(&p->pending_input_data, data, 8);
739 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
740 "unexpected reply code version",
741 PROXY_ERROR_GENERAL, 0);
749 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
750 PROXY_ERROR_GENERAL, 0);
753 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
754 PROXY_ERROR_GENERAL, 0);
758 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
759 PROXY_ERROR_GENERAL, 0);
765 bufchain_consume(&p->pending_input_data, 8);
769 /* proxy activate will have dealt with
770 * whatever is left of the buffer */
775 plug_closing(p->plug, "Proxy error: unexpected proxy error",
776 PROXY_ERROR_UNEXPECTED, 0);
780 /* SOCKS version 5 */
781 int proxy_socks5_negotiate (Proxy_Socket p, int change)
783 if (p->state == PROXY_CHANGE_NEW) {
786 * version number (1 byte) = 5
787 * number of available authentication methods (1 byte)
788 * available authentication methods (1 byte * previous value)
789 * authentication methods:
790 * 0x00 = no authentication
792 * 0x02 = username/password
799 command[0] = 5; /* version 5 */
800 if (cfg.proxy_username[0] || cfg.proxy_password[0]) {
801 command[1] = 2; /* two methods supported: */
802 command[2] = 0x00; /* no authentication */
803 command[3] = 0x02; /* username/password */
806 command[1] = 1; /* one methods supported: */
807 command[2] = 0x00; /* no authentication */
811 sk_write(p->sub_socket, command, len);
817 if (change == PROXY_CHANGE_CLOSING) {
818 /* if our proxy negotiation process involves closing and opening
819 * new sockets, then we would want to intercept this closing
820 * callback when we were expecting it. if we aren't anticipating
821 * a socket close, then some error must have occurred. we'll
822 * just pass those errors up to the backend.
824 return plug_closing(p->plug, p->closing_error_msg,
825 p->closing_error_code,
826 p->closing_calling_back);
829 if (change == PROXY_CHANGE_SENT) {
830 /* some (or all) of what we wrote to the proxy was sent.
831 * we don't do anything new, however, until we receive the
832 * proxy's response. we might want to set a timer so we can
833 * timeout the proxy negotiation after a while...
838 if (change == PROXY_CHANGE_ACCEPTING) {
839 /* we should _never_ see this, as we are using our socket to
840 * connect to a proxy, not accepting inbound connections.
841 * what should we do? close the socket with an appropriate
844 return plug_accepting(p->plug, p->accepting_sock);
847 if (change == PROXY_CHANGE_RECEIVE) {
848 /* we have received data from the underlying socket, which
849 * we'll need to parse, process, and respond to appropriately.
855 * version number (1 byte) = 5
856 * authentication method (1 byte)
857 * authentication methods:
858 * 0x00 = no authentication
860 * 0x02 = username/password
862 * 0xff = no acceptable methods
866 if (bufchain_size(&p->pending_input_data) < 2)
867 return 1; /* not got anything yet */
869 /* get the response */
870 bufchain_fetch(&p->pending_input_data, data, 2);
873 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
874 PROXY_ERROR_GENERAL, 0);
878 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
879 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
880 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
881 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
883 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
884 PROXY_ERROR_GENERAL, 0);
887 bufchain_consume(&p->pending_input_data, 2);
892 /* password authentication reply format:
893 * version number (1 bytes) = 1
894 * reply code (1 byte)
900 if (bufchain_size(&p->pending_input_data) < 2)
901 return 1; /* not got anything yet */
903 /* get the response */
904 bufchain_fetch(&p->pending_input_data, data, 2);
907 plug_closing(p->plug, "Proxy error: SOCKS password "
908 "subnegotiation contained wrong version number",
909 PROXY_ERROR_GENERAL, 0);
915 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
916 " password authentication",
917 PROXY_ERROR_GENERAL, 0);
921 bufchain_consume(&p->pending_input_data, 2);
922 p->state = 2; /* now proceed as authenticated */
928 * version number (1 byte) = 5
929 * command code (1 byte)
933 * reserved (1 byte) = 0x00
934 * address type (1 byte)
936 * 3 = domainname (first byte has length, no terminating null)
938 * dest. address (variable)
939 * dest. port (2 bytes) [network order]
945 if (sk_addrtype(p->remote_addr) == ADDRTYPE_IPV4) {
947 command[3] = 1; /* IPv4 */
950 command[3] = 4; /* IPv6 */
953 command[0] = 5; /* version 5 */
954 command[1] = 1; /* CONNECT command */
958 sk_addrcopy(p->remote_addr, command+4);
961 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
962 command[len-1] = (char) p->remote_port & 0xff;
964 sk_write(p->sub_socket, command, len);
973 * version number (1 bytes) = 5
974 * reply code (1 byte)
976 * 1 = general SOCKS server failure
977 * 2 = connection not allowed by ruleset
978 * 3 = network unreachable
979 * 4 = host unreachable
980 * 5 = connection refused
982 * 7 = command not supported
983 * 8 = address type not supported
984 * reserved (1 byte) = x00
985 * address type (1 byte)
987 * 3 = domainname (first byte has length, no terminating null)
989 * server bound address (variable)
990 * server bound port (2 bytes) [network order]
995 /* First 5 bytes of packet are enough to tell its length. */
996 if (bufchain_size(&p->pending_input_data) < 5)
997 return 1; /* not got anything yet */
999 /* get the response */
1000 bufchain_fetch(&p->pending_input_data, data, 5);
1003 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1004 PROXY_ERROR_GENERAL, 0);
1011 strcpy(buf, "Proxy error: ");
1014 case 1: strcat(buf, "General SOCKS server failure"); break;
1015 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1016 case 3: strcat(buf, "Network unreachable"); break;
1017 case 4: strcat(buf, "Host unreachable"); break;
1018 case 5: strcat(buf, "Connection refused"); break;
1019 case 6: strcat(buf, "TTL expired"); break;
1020 case 7: strcat(buf, "Command not supported"); break;
1021 case 8: strcat(buf, "Address type not supported"); break;
1022 default: sprintf(buf+strlen(buf),
1023 "Unrecognised SOCKS error code %d",
1027 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1033 * Eat the rest of the reply packet.
1035 len = 6; /* first 4 bytes, last 2 */
1037 case 1: len += 4; break; /* IPv4 address */
1038 case 4: len += 16; break;/* IPv6 address */
1039 case 3: len += (unsigned char)data[4]; break; /* domain name */
1041 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1042 "unrecognised address format",
1043 PROXY_ERROR_GENERAL, 0);
1046 if (bufchain_size(&p->pending_input_data) < len)
1047 return 1; /* not got whole reply yet */
1048 bufchain_consume(&p->pending_input_data, len);
1055 if (p->state == 4) {
1056 /* TODO: Handle GSSAPI authentication */
1057 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1058 PROXY_ERROR_GENERAL, 0);
1062 if (p->state == 5) {
1063 if (cfg.proxy_username[0] || cfg.proxy_password[0]) {
1064 char userpwbuf[514];
1066 ulen = strlen(cfg.proxy_username);
1067 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1068 plen = strlen(cfg.proxy_password);
1069 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1070 userpwbuf[0] = 1; /* version number of subnegotiation */
1071 userpwbuf[1] = ulen;
1072 memcpy(userpwbuf+2, cfg.proxy_username, ulen);
1073 userpwbuf[ulen+2] = plen;
1074 memcpy(userpwbuf+ulen+3, cfg.proxy_password, plen);
1075 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1078 plug_closing(p->plug, "Proxy error: Server chose "
1079 "username/password authentication but we "
1081 PROXY_ERROR_GENERAL, 0);
1085 if (p->state == 6) {
1086 /* TODO: Handle CHAP authentication */
1087 plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
1088 PROXY_ERROR_GENERAL, 0);
1094 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1095 PROXY_ERROR_UNEXPECTED, 0);
1099 /* ----------------------------------------------------------------------
1100 * `Telnet' proxy type.
1102 * (This is for ad-hoc proxies where you connect to the proxy's
1103 * telnet port and send a command such as `connect host port'. The
1104 * command is configurable, since this proxy type is typically not
1105 * standardised or at all well-defined.)
1108 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1110 if (p->state == PROXY_CHANGE_NEW) {
1114 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1115 * %%, %host, %port, %user, and %pass
1118 while (cfg.proxy_telnet_command[eo] != 0) {
1120 /* scan forward until we hit end-of-line,
1121 * or an escape character (\ or %) */
1122 while (cfg.proxy_telnet_command[eo] != 0 &&
1123 cfg.proxy_telnet_command[eo] != '%' &&
1124 cfg.proxy_telnet_command[eo] != '\\') eo++;
1126 /* if we hit eol, break out of our escaping loop */
1127 if (cfg.proxy_telnet_command[eo] == 0) break;
1129 /* if there was any unescaped text before the escape
1130 * character, send that now */
1132 sk_write(p->sub_socket,
1133 cfg.proxy_telnet_command + so, eo - so);
1138 /* if the escape character was the last character of
1139 * the line, we'll just stop and send it. */
1140 if (cfg.proxy_telnet_command[eo] == 0) break;
1142 if (cfg.proxy_telnet_command[so] == '\\') {
1144 /* we recognize \\, \%, \r, \n, \t, \x??.
1145 * anything else, we just send unescaped (including the \).
1148 switch (cfg.proxy_telnet_command[eo]) {
1151 sk_write(p->sub_socket, "\\", 1);
1156 sk_write(p->sub_socket, "%%", 1);
1161 sk_write(p->sub_socket, "\r", 1);
1166 sk_write(p->sub_socket, "\n", 1);
1171 sk_write(p->sub_socket, "\t", 1);
1178 /* escaped hexadecimal value (ie. \xff) */
1179 unsigned char v = 0;
1184 if (cfg.proxy_telnet_command[eo] >= '0' &&
1185 cfg.proxy_telnet_command[eo] <= '9')
1186 v += cfg.proxy_telnet_command[eo] - '0';
1187 else if (cfg.proxy_telnet_command[eo] >= 'a' &&
1188 cfg.proxy_telnet_command[eo] <= 'f')
1189 v += cfg.proxy_telnet_command[eo] - 'a' + 10;
1190 else if (cfg.proxy_telnet_command[eo] >= 'A' &&
1191 cfg.proxy_telnet_command[eo] <= 'F')
1192 v += cfg.proxy_telnet_command[eo] - 'A' + 10;
1194 /* non hex character, so we abort and just
1195 * send the whole thing unescaped (including \x)
1197 sk_write(p->sub_socket, "\\", 1);
1202 /* we only extract two hex characters */
1204 sk_write(p->sub_socket, &v, 1);
1216 sk_write(p->sub_socket,
1217 cfg.proxy_telnet_command + so, 2);
1223 /* % escape. we recognize %%, %host, %port, %user, %pass.
1224 * anything else, we just send unescaped (including the %).
1227 if (cfg.proxy_telnet_command[eo] == '%') {
1228 sk_write(p->sub_socket, "%", 1);
1231 else if (strnicmp(cfg.proxy_telnet_command + eo,
1234 sk_getaddr(p->remote_addr, dest, 64);
1235 sk_write(p->sub_socket, dest, strlen(dest));
1238 else if (strnicmp(cfg.proxy_telnet_command + eo,
1241 sprintf(port, "%i", p->remote_port);
1242 sk_write(p->sub_socket, port, strlen(port));
1245 else if (strnicmp(cfg.proxy_telnet_command + eo,
1247 sk_write(p->sub_socket, cfg.proxy_username,
1248 strlen(cfg.proxy_username));
1251 else if (strnicmp(cfg.proxy_telnet_command + eo,
1253 sk_write(p->sub_socket, cfg.proxy_password,
1254 strlen(cfg.proxy_password));
1258 /* we don't escape this, so send the % now, and
1259 * don't advance eo, so that we'll consider the
1260 * text immediately following the % as unescaped.
1262 sk_write(p->sub_socket, "%", 1);
1266 /* resume scanning for additional escapes after this one. */
1270 /* if there is any unescaped text at the end of the line, send it */
1272 sk_write(p->sub_socket, cfg.proxy_telnet_command + so, eo - so);
1279 if (change == PROXY_CHANGE_CLOSING) {
1280 /* if our proxy negotiation process involves closing and opening
1281 * new sockets, then we would want to intercept this closing
1282 * callback when we were expecting it. if we aren't anticipating
1283 * a socket close, then some error must have occurred. we'll
1284 * just pass those errors up to the backend.
1286 return plug_closing(p->plug, p->closing_error_msg,
1287 p->closing_error_code,
1288 p->closing_calling_back);
1291 if (change == PROXY_CHANGE_SENT) {
1292 /* some (or all) of what we wrote to the proxy was sent.
1293 * we don't do anything new, however, until we receive the
1294 * proxy's response. we might want to set a timer so we can
1295 * timeout the proxy negotiation after a while...
1300 if (change == PROXY_CHANGE_ACCEPTING) {
1301 /* we should _never_ see this, as we are using our socket to
1302 * connect to a proxy, not accepting inbound connections.
1303 * what should we do? close the socket with an appropriate
1306 return plug_accepting(p->plug, p->accepting_sock);
1309 if (change == PROXY_CHANGE_RECEIVE) {
1310 /* we have received data from the underlying socket, which
1311 * we'll need to parse, process, and respond to appropriately.
1316 /* proxy activate will have dealt with
1317 * whatever is left of the buffer */
1321 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1322 PROXY_ERROR_UNEXPECTED, 0);