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
17 #define do_proxy_dns(cfg) \
18 (cfg->proxy_dns == FORCE_ON || \
19 (cfg->proxy_dns == AUTO && \
20 cfg->proxy_type != PROXY_SOCKS4 && \
21 cfg->proxy_type != PROXY_SOCKS5))
24 * Call this when proxy negotiation is complete, so that this
25 * socket can begin working normally.
27 void proxy_activate (Proxy_Socket p)
31 long output_before, output_after;
33 p->state = PROXY_STATE_ACTIVE;
35 /* we want to ignore new receive events until we have sent
36 * all of our buffered receive data.
38 sk_set_frozen(p->sub_socket, 1);
40 /* how many bytes of output have we buffered? */
41 output_before = bufchain_size(&p->pending_oob_output_data) +
42 bufchain_size(&p->pending_output_data);
43 /* and keep track of how many bytes do not get sent. */
46 /* send buffered OOB writes */
47 while (bufchain_size(&p->pending_oob_output_data) > 0) {
48 bufchain_prefix(&p->pending_oob_output_data, &data, &len);
49 output_after += sk_write_oob(p->sub_socket, data, len);
50 bufchain_consume(&p->pending_oob_output_data, len);
53 /* send buffered normal writes */
54 while (bufchain_size(&p->pending_output_data) > 0) {
55 bufchain_prefix(&p->pending_output_data, &data, &len);
56 output_after += sk_write(p->sub_socket, data, len);
57 bufchain_consume(&p->pending_output_data, len);
60 /* if we managed to send any data, let the higher levels know. */
61 if (output_after < output_before)
62 plug_sent(p->plug, output_after);
64 /* if we were asked to flush the output during
65 * the proxy negotiation process, do so now.
67 if (p->pending_flush) sk_flush(p->sub_socket);
69 /* if the backend wanted the socket unfrozen, try to unfreeze.
70 * our set_frozen handler will flush buffered receive data before
71 * unfreezing the actual underlying socket.
74 sk_set_frozen((Socket)p, 0);
77 /* basic proxy socket functions */
79 static Plug sk_proxy_plug (Socket s, Plug p)
81 Proxy_Socket ps = (Proxy_Socket) s;
88 static void sk_proxy_close (Socket s)
90 Proxy_Socket ps = (Proxy_Socket) s;
92 sk_close(ps->sub_socket);
93 sk_addr_free(ps->remote_addr);
97 static int sk_proxy_write (Socket s, const char *data, int len)
99 Proxy_Socket ps = (Proxy_Socket) s;
101 if (ps->state != PROXY_STATE_ACTIVE) {
102 bufchain_add(&ps->pending_output_data, data, len);
103 return bufchain_size(&ps->pending_output_data);
105 return sk_write(ps->sub_socket, data, len);
108 static int sk_proxy_write_oob (Socket s, const char *data, int len)
110 Proxy_Socket ps = (Proxy_Socket) s;
112 if (ps->state != PROXY_STATE_ACTIVE) {
113 bufchain_clear(&ps->pending_output_data);
114 bufchain_clear(&ps->pending_oob_output_data);
115 bufchain_add(&ps->pending_oob_output_data, data, len);
118 return sk_write_oob(ps->sub_socket, data, len);
121 static void sk_proxy_flush (Socket s)
123 Proxy_Socket ps = (Proxy_Socket) s;
125 if (ps->state != PROXY_STATE_ACTIVE) {
126 ps->pending_flush = 1;
129 sk_flush(ps->sub_socket);
132 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
134 Proxy_Socket ps = (Proxy_Socket) s;
135 sk_set_private_ptr(ps->sub_socket, ptr);
138 static void * sk_proxy_get_private_ptr (Socket s)
140 Proxy_Socket ps = (Proxy_Socket) s;
141 return sk_get_private_ptr(ps->sub_socket);
144 static void sk_proxy_set_frozen (Socket s, int is_frozen)
146 Proxy_Socket ps = (Proxy_Socket) s;
148 if (ps->state != PROXY_STATE_ACTIVE) {
149 ps->freeze = is_frozen;
153 /* handle any remaining buffered recv data first */
154 if (bufchain_size(&ps->pending_input_data) > 0) {
155 ps->freeze = is_frozen;
157 /* loop while we still have buffered data, and while we are
158 * unfrozen. the plug_receive call in the loop could result
159 * in a call back into this function refreezing the socket,
160 * so we have to check each time.
162 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
166 bufchain_prefix(&ps->pending_input_data, &data, &len);
167 if (len > lenof(databuf))
168 len = lenof(databuf);
169 memcpy(databuf, data, len);
170 bufchain_consume(&ps->pending_input_data, len);
171 plug_receive(ps->plug, 0, databuf, len);
174 /* if we're still frozen, we'll have to wait for another
175 * call from the backend to finish unbuffering the data.
177 if (ps->freeze) return;
180 sk_set_frozen(ps->sub_socket, is_frozen);
183 static const char * sk_proxy_socket_error (Socket s)
185 Proxy_Socket ps = (Proxy_Socket) s;
186 if (ps->error != NULL || ps->sub_socket == NULL) {
189 return sk_socket_error(ps->sub_socket);
192 /* basic proxy plug functions */
194 static int plug_proxy_closing (Plug p, const char *error_msg,
195 int error_code, int calling_back)
197 Proxy_Plug pp = (Proxy_Plug) p;
198 Proxy_Socket ps = pp->proxy_socket;
200 if (ps->state != PROXY_STATE_ACTIVE) {
201 ps->closing_error_msg = error_msg;
202 ps->closing_error_code = error_code;
203 ps->closing_calling_back = calling_back;
204 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
206 return plug_closing(ps->plug, error_msg,
207 error_code, calling_back);
210 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
212 Proxy_Plug pp = (Proxy_Plug) p;
213 Proxy_Socket ps = pp->proxy_socket;
215 if (ps->state != PROXY_STATE_ACTIVE) {
216 /* we will lose the urgentness of this data, but since most,
217 * if not all, of this data will be consumed by the negotiation
218 * process, hopefully it won't affect the protocol above us
220 bufchain_add(&ps->pending_input_data, data, len);
221 ps->receive_urgent = urgent;
222 ps->receive_data = data;
223 ps->receive_len = len;
224 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
226 return plug_receive(ps->plug, urgent, data, len);
229 static void plug_proxy_sent (Plug p, int bufsize)
231 Proxy_Plug pp = (Proxy_Plug) p;
232 Proxy_Socket ps = pp->proxy_socket;
234 if (ps->state != PROXY_STATE_ACTIVE) {
235 ps->sent_bufsize = bufsize;
236 ps->negotiate(ps, PROXY_CHANGE_SENT);
239 plug_sent(ps->plug, bufsize);
242 static int plug_proxy_accepting (Plug p, OSSocket sock)
244 Proxy_Plug pp = (Proxy_Plug) p;
245 Proxy_Socket ps = pp->proxy_socket;
247 if (ps->state != PROXY_STATE_ACTIVE) {
248 ps->accepting_sock = sock;
249 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
251 return plug_accepting(ps->plug, sock);
255 * This function can accept a NULL pointer as `addr', in which case
256 * it will only check the host name.
258 static int proxy_for_destination (SockAddr addr, char *hostname, int port,
263 int hostip_len, hostname_len;
264 const char *exclude_list;
267 * Check the host name and IP against the hard-coded
268 * representations of `localhost'.
270 if (!cfg->even_proxy_localhost &&
271 (sk_hostname_is_local(hostname) ||
272 (addr && sk_address_is_local(addr))))
273 return 0; /* do not proxy */
275 /* we want a string representation of the IP address for comparisons */
277 sk_getaddr(addr, hostip, 64);
278 hostip_len = strlen(hostip);
280 hostip_len = 0; /* placate gcc; shouldn't be required */
282 hostname_len = strlen(hostname);
284 exclude_list = cfg->proxy_exclude_list;
286 /* now parse the exclude list, and see if either our IP
287 * or hostname matches anything in it.
290 while (exclude_list[s]) {
291 while (exclude_list[s] &&
292 (isspace((unsigned char)exclude_list[s]) ||
293 exclude_list[s] == ',')) s++;
295 if (!exclude_list[s]) break;
299 while (exclude_list[e] &&
300 (isalnum((unsigned char)exclude_list[e]) ||
301 exclude_list[e] == '-' ||
302 exclude_list[e] == '.' ||
303 exclude_list[e] == '*')) e++;
305 if (exclude_list[s] == '*') {
306 /* wildcard at beginning of entry */
308 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
309 exclude_list + s + 1, e - s - 1) == 0) ||
310 strnicmp(hostname + hostname_len - (e - s - 1),
311 exclude_list + s + 1, e - s - 1) == 0)
312 return 0; /* IP/hostname range excluded. do not use proxy. */
314 } else if (exclude_list[e-1] == '*') {
315 /* wildcard at end of entry */
317 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
318 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
319 return 0; /* IP/hostname range excluded. do not use proxy. */
322 /* no wildcard at either end, so let's try an absolute
323 * match (ie. a specific IP)
326 if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
327 return 0; /* IP/hostname excluded. do not use proxy. */
328 if (strnicmp(hostname, exclude_list + s, e - s) == 0)
329 return 0; /* IP/hostname excluded. do not use proxy. */
334 /* Make sure we really have reached the next comma or end-of-string */
335 while (exclude_list[s] &&
336 !isspace((unsigned char)exclude_list[s]) &&
337 exclude_list[s] != ',') s++;
340 /* no matches in the exclude list, so use the proxy */
344 SockAddr name_lookup(char *host, int port, char **canonicalname,
347 if (cfg->proxy_type != PROXY_NONE &&
349 proxy_for_destination(NULL, host, port, cfg)) {
350 *canonicalname = dupstr(host);
351 return sk_nonamelookup(host);
354 return sk_namelookup(host, canonicalname);
357 Socket new_connection(SockAddr addr, char *hostname,
358 int port, int privport,
359 int oobinline, int nodelay, Plug plug,
362 static const struct socket_function_table socket_fn_table = {
368 sk_proxy_set_private_ptr,
369 sk_proxy_get_private_ptr,
371 sk_proxy_socket_error
374 static const struct plug_function_table plug_fn_table = {
381 if (cfg->proxy_type != PROXY_NONE &&
382 proxy_for_destination(addr, hostname, port, cfg))
387 char *proxy_canonical_name;
390 if ((sret = platform_new_connection(addr, hostname, port, privport,
391 oobinline, nodelay, plug, cfg)) !=
395 ret = snew(struct Socket_proxy_tag);
396 ret->fn = &socket_fn_table;
397 ret->cfg = *cfg; /* STRUCTURE COPY */
399 ret->remote_addr = addr; /* will need to be freed on close */
400 ret->remote_port = port;
403 ret->pending_flush = 0;
406 bufchain_init(&ret->pending_input_data);
407 bufchain_init(&ret->pending_output_data);
408 bufchain_init(&ret->pending_oob_output_data);
410 ret->sub_socket = NULL;
411 ret->state = PROXY_STATE_NEW;
412 ret->negotiate = NULL;
414 if (cfg->proxy_type == PROXY_HTTP) {
415 ret->negotiate = proxy_http_negotiate;
416 } else if (cfg->proxy_type == PROXY_SOCKS4) {
417 ret->negotiate = proxy_socks4_negotiate;
418 } else if (cfg->proxy_type == PROXY_SOCKS5) {
419 ret->negotiate = proxy_socks5_negotiate;
420 } else if (cfg->proxy_type == PROXY_TELNET) {
421 ret->negotiate = proxy_telnet_negotiate;
423 ret->error = "Proxy error: Unknown proxy method";
427 /* create the proxy plug to map calls from the actual
428 * socket into our proxy socket layer */
429 pplug = snew(struct Plug_proxy_tag);
430 pplug->fn = &plug_fn_table;
431 pplug->proxy_socket = ret;
434 proxy_addr = sk_namelookup(cfg->proxy_host,
435 &proxy_canonical_name);
436 if (sk_addr_error(proxy_addr) != NULL) {
437 ret->error = "Proxy error: Unable to resolve proxy host name";
440 sfree(proxy_canonical_name);
442 /* create the actual socket we will be using,
443 * connected to our proxy server and port.
445 ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port,
447 nodelay, (Plug) pplug);
448 if (sk_socket_error(ret->sub_socket) != NULL)
451 /* start the proxy negotiation process... */
452 sk_set_frozen(ret->sub_socket, 0);
453 ret->negotiate(ret, PROXY_CHANGE_NEW);
458 /* no proxy, so just return the direct socket */
459 return sk_new(addr, port, privport, oobinline, nodelay, plug);
462 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
465 /* TODO: SOCKS (and potentially others) support inbound
466 * TODO: connections via the proxy. support them.
469 return sk_newlistener(srcaddr, port, plug, local_host_only);
472 /* ----------------------------------------------------------------------
473 * HTTP CONNECT proxy type.
476 static int get_line_end (char * data, int len)
482 if (data[off] == '\n') {
483 /* we have a newline */
486 /* is that the only thing on this line? */
487 if (off <= 2) return off;
489 /* if not, then there is the possibility that this header
490 * continues onto the next line, if it starts with a space
495 data[off+1] != ' ' &&
496 data[off+1] != '\t') return off;
498 /* the line does continue, so we have to keep going
499 * until we see an the header's "real" end of line.
510 int proxy_http_negotiate (Proxy_Socket p, int change)
512 if (p->state == PROXY_STATE_NEW) {
513 /* we are just beginning the proxy negotiate process,
514 * so we'll send off the initial bits of the request.
515 * for this proxy method, it's just a simple HTTP
518 char *buf, dest[512];
520 sk_getaddr(p->remote_addr, dest, lenof(dest));
522 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
523 dest, p->remote_port, dest, p->remote_port);
524 sk_write(p->sub_socket, buf, strlen(buf));
527 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
528 char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
529 char buf2[sizeof(buf)*4/3 + 100];
531 sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
533 sprintf(buf2, "Proxy-Authorization: Basic ");
534 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
535 base64_encode_atom((unsigned char *)(buf+i),
536 (len-i > 3 ? 3 : len-i), buf2+j);
537 strcpy(buf2+j, "\r\n");
538 sk_write(p->sub_socket, buf2, strlen(buf2));
541 sk_write(p->sub_socket, "\r\n", 2);
547 if (change == PROXY_CHANGE_CLOSING) {
548 /* if our proxy negotiation process involves closing and opening
549 * new sockets, then we would want to intercept this closing
550 * callback when we were expecting it. if we aren't anticipating
551 * a socket close, then some error must have occurred. we'll
552 * just pass those errors up to the backend.
554 return plug_closing(p->plug, p->closing_error_msg,
555 p->closing_error_code,
556 p->closing_calling_back);
559 if (change == PROXY_CHANGE_SENT) {
560 /* some (or all) of what we wrote to the proxy was sent.
561 * we don't do anything new, however, until we receive the
562 * proxy's response. we might want to set a timer so we can
563 * timeout the proxy negotiation after a while...
568 if (change == PROXY_CHANGE_ACCEPTING) {
569 /* we should _never_ see this, as we are using our socket to
570 * connect to a proxy, not accepting inbound connections.
571 * what should we do? close the socket with an appropriate
574 return plug_accepting(p->plug, p->accepting_sock);
577 if (change == PROXY_CHANGE_RECEIVE) {
578 /* we have received data from the underlying socket, which
579 * we'll need to parse, process, and respond to appropriately.
588 int min_ver, maj_ver, status;
590 /* get the status line */
591 len = bufchain_size(&p->pending_input_data);
592 assert(len > 0); /* or we wouldn't be here */
593 data = snewn(len, char);
594 bufchain_fetch(&p->pending_input_data, data, len);
596 eol = get_line_end(data, len);
603 /* We can't rely on whether the %n incremented the sscanf return */
604 if (sscanf((char *)data, "HTTP/%i.%i %n",
605 &maj_ver, &min_ver, &status) < 2 || status == -1) {
606 plug_closing(p->plug, "Proxy error: HTTP response was absent",
607 PROXY_ERROR_GENERAL, 0);
612 /* remove the status line from the input buffer. */
613 bufchain_consume(&p->pending_input_data, eol);
614 if (data[status] != '2') {
618 while (eol > status &&
619 (data[eol-1] == '\r' || data[eol-1] == '\n'))
621 buf = dupprintf("Proxy error: %s", data+status);
622 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
635 /* get headers. we're done when we get a
636 * header of length 2, (ie. just "\r\n")
639 len = bufchain_size(&p->pending_input_data);
640 assert(len > 0); /* or we wouldn't be here */
641 data = snewn(len, char);
643 bufchain_fetch(&p->pending_input_data, data, len);
645 eol = get_line_end(datap, len);
652 bufchain_consume(&p->pending_input_data, eol);
655 eol = get_line_end(datap, len);
660 bufchain_consume(&p->pending_input_data, 2);
662 /* proxy activate will have dealt with
663 * whatever is left of the buffer */
673 plug_closing(p->plug, "Proxy error: unexpected proxy error",
674 PROXY_ERROR_UNEXPECTED, 0);
678 /* ----------------------------------------------------------------------
682 /* SOCKS version 4 */
683 int proxy_socks4_negotiate (Proxy_Socket p, int change)
685 if (p->state == PROXY_CHANGE_NEW) {
688 * version number (1 byte) = 4
689 * command code (1 byte)
692 * dest. port (2 bytes) [network order]
693 * dest. address (4 bytes)
694 * user ID (variable length, null terminated string)
697 int length, type, namelen;
698 char *command, addr[4], hostname[512];
700 type = sk_addrtype(p->remote_addr);
701 if (type == ADDRTYPE_IPV6) {
702 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
703 " not support IPv6", PROXY_ERROR_GENERAL, 0);
705 } else if (type == ADDRTYPE_IPV4) {
707 sk_addrcopy(p->remote_addr, addr);
708 } else { /* type == ADDRTYPE_NAME */
709 assert(type == ADDRTYPE_NAME);
710 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
711 namelen = strlen(hostname) + 1; /* include the NUL */
712 addr[0] = addr[1] = addr[2] = 0;
716 length = strlen(p->cfg.proxy_username) + namelen + 9;
717 command = snewn(length, char);
718 strcpy(command + 8, p->cfg.proxy_username);
720 command[0] = 4; /* version 4 */
721 command[1] = 1; /* CONNECT command */
724 command[2] = (char) (p->remote_port >> 8) & 0xff;
725 command[3] = (char) p->remote_port & 0xff;
728 memcpy(command + 4, addr, 4);
731 memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1,
734 sk_write(p->sub_socket, command, length);
741 if (change == PROXY_CHANGE_CLOSING) {
742 /* if our proxy negotiation process involves closing and opening
743 * new sockets, then we would want to intercept this closing
744 * callback when we were expecting it. if we aren't anticipating
745 * a socket close, then some error must have occurred. we'll
746 * just pass those errors up to the backend.
748 return plug_closing(p->plug, p->closing_error_msg,
749 p->closing_error_code,
750 p->closing_calling_back);
753 if (change == PROXY_CHANGE_SENT) {
754 /* some (or all) of what we wrote to the proxy was sent.
755 * we don't do anything new, however, until we receive the
756 * proxy's response. we might want to set a timer so we can
757 * timeout the proxy negotiation after a while...
762 if (change == PROXY_CHANGE_ACCEPTING) {
763 /* we should _never_ see this, as we are using our socket to
764 * connect to a proxy, not accepting inbound connections.
765 * what should we do? close the socket with an appropriate
768 return plug_accepting(p->plug, p->accepting_sock);
771 if (change == PROXY_CHANGE_RECEIVE) {
772 /* we have received data from the underlying socket, which
773 * we'll need to parse, process, and respond to appropriately.
778 * version number (1 byte) = 4
779 * reply code (1 byte)
780 * 90 = request granted
781 * 91 = request rejected or failed
782 * 92 = request rejected due to lack of IDENTD on client
783 * 93 = request rejected due to difference in user ID
784 * (what we sent vs. what IDENTD said)
785 * dest. port (2 bytes)
786 * dest. address (4 bytes)
791 if (bufchain_size(&p->pending_input_data) < 8)
792 return 1; /* not got anything yet */
794 /* get the response */
795 bufchain_fetch(&p->pending_input_data, data, 8);
798 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
799 "unexpected reply code version",
800 PROXY_ERROR_GENERAL, 0);
808 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
809 PROXY_ERROR_GENERAL, 0);
812 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
813 PROXY_ERROR_GENERAL, 0);
817 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
818 PROXY_ERROR_GENERAL, 0);
824 bufchain_consume(&p->pending_input_data, 8);
828 /* proxy activate will have dealt with
829 * whatever is left of the buffer */
834 plug_closing(p->plug, "Proxy error: unexpected proxy error",
835 PROXY_ERROR_UNEXPECTED, 0);
839 /* SOCKS version 5 */
840 int proxy_socks5_negotiate (Proxy_Socket p, int change)
842 if (p->state == PROXY_CHANGE_NEW) {
845 * version number (1 byte) = 5
846 * number of available authentication methods (1 byte)
847 * available authentication methods (1 byte * previous value)
848 * authentication methods:
849 * 0x00 = no authentication
851 * 0x02 = username/password
858 command[0] = 5; /* version 5 */
859 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
860 command[1] = 2; /* two methods supported: */
861 command[2] = 0x00; /* no authentication */
862 command[3] = 0x02; /* username/password */
865 command[1] = 1; /* one methods supported: */
866 command[2] = 0x00; /* no authentication */
870 sk_write(p->sub_socket, command, len);
876 if (change == PROXY_CHANGE_CLOSING) {
877 /* if our proxy negotiation process involves closing and opening
878 * new sockets, then we would want to intercept this closing
879 * callback when we were expecting it. if we aren't anticipating
880 * a socket close, then some error must have occurred. we'll
881 * just pass those errors up to the backend.
883 return plug_closing(p->plug, p->closing_error_msg,
884 p->closing_error_code,
885 p->closing_calling_back);
888 if (change == PROXY_CHANGE_SENT) {
889 /* some (or all) of what we wrote to the proxy was sent.
890 * we don't do anything new, however, until we receive the
891 * proxy's response. we might want to set a timer so we can
892 * timeout the proxy negotiation after a while...
897 if (change == PROXY_CHANGE_ACCEPTING) {
898 /* we should _never_ see this, as we are using our socket to
899 * connect to a proxy, not accepting inbound connections.
900 * what should we do? close the socket with an appropriate
903 return plug_accepting(p->plug, p->accepting_sock);
906 if (change == PROXY_CHANGE_RECEIVE) {
907 /* we have received data from the underlying socket, which
908 * we'll need to parse, process, and respond to appropriately.
914 * version number (1 byte) = 5
915 * authentication method (1 byte)
916 * authentication methods:
917 * 0x00 = no authentication
919 * 0x02 = username/password
921 * 0xff = no acceptable methods
925 if (bufchain_size(&p->pending_input_data) < 2)
926 return 1; /* not got anything yet */
928 /* get the response */
929 bufchain_fetch(&p->pending_input_data, data, 2);
932 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
933 PROXY_ERROR_GENERAL, 0);
937 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
938 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
939 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
940 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
942 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
943 PROXY_ERROR_GENERAL, 0);
946 bufchain_consume(&p->pending_input_data, 2);
951 /* password authentication reply format:
952 * version number (1 bytes) = 1
953 * reply code (1 byte)
959 if (bufchain_size(&p->pending_input_data) < 2)
960 return 1; /* not got anything yet */
962 /* get the response */
963 bufchain_fetch(&p->pending_input_data, data, 2);
966 plug_closing(p->plug, "Proxy error: SOCKS password "
967 "subnegotiation contained wrong version number",
968 PROXY_ERROR_GENERAL, 0);
974 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
975 " password authentication",
976 PROXY_ERROR_GENERAL, 0);
980 bufchain_consume(&p->pending_input_data, 2);
981 p->state = 2; /* now proceed as authenticated */
987 * version number (1 byte) = 5
988 * command code (1 byte)
992 * reserved (1 byte) = 0x00
993 * address type (1 byte)
995 * 3 = domainname (first byte has length, no terminating null)
997 * dest. address (variable)
998 * dest. port (2 bytes) [network order]
1005 type = sk_addrtype(p->remote_addr);
1006 if (type == ADDRTYPE_IPV4) {
1007 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1008 command[3] = 1; /* IPv4 */
1009 sk_addrcopy(p->remote_addr, command+4);
1010 } else if (type == ADDRTYPE_IPV6) {
1011 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1012 command[3] = 4; /* IPv6 */
1013 sk_addrcopy(p->remote_addr, command+4);
1015 assert(type == ADDRTYPE_NAME);
1017 sk_getaddr(p->remote_addr, command+5, 256);
1018 command[4] = strlen(command+5);
1019 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1022 command[0] = 5; /* version 5 */
1023 command[1] = 1; /* CONNECT command */
1027 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1028 command[len-1] = (char) p->remote_port & 0xff;
1030 sk_write(p->sub_socket, command, len);
1036 if (p->state == 3) {
1039 * version number (1 bytes) = 5
1040 * reply code (1 byte)
1042 * 1 = general SOCKS server failure
1043 * 2 = connection not allowed by ruleset
1044 * 3 = network unreachable
1045 * 4 = host unreachable
1046 * 5 = connection refused
1048 * 7 = command not supported
1049 * 8 = address type not supported
1050 * reserved (1 byte) = x00
1051 * address type (1 byte)
1053 * 3 = domainname (first byte has length, no terminating null)
1055 * server bound address (variable)
1056 * server bound port (2 bytes) [network order]
1061 /* First 5 bytes of packet are enough to tell its length. */
1062 if (bufchain_size(&p->pending_input_data) < 5)
1063 return 1; /* not got anything yet */
1065 /* get the response */
1066 bufchain_fetch(&p->pending_input_data, data, 5);
1069 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1070 PROXY_ERROR_GENERAL, 0);
1077 strcpy(buf, "Proxy error: ");
1080 case 1: strcat(buf, "General SOCKS server failure"); break;
1081 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1082 case 3: strcat(buf, "Network unreachable"); break;
1083 case 4: strcat(buf, "Host unreachable"); break;
1084 case 5: strcat(buf, "Connection refused"); break;
1085 case 6: strcat(buf, "TTL expired"); break;
1086 case 7: strcat(buf, "Command not supported"); break;
1087 case 8: strcat(buf, "Address type not supported"); break;
1088 default: sprintf(buf+strlen(buf),
1089 "Unrecognised SOCKS error code %d",
1093 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1099 * Eat the rest of the reply packet.
1101 len = 6; /* first 4 bytes, last 2 */
1103 case 1: len += 4; break; /* IPv4 address */
1104 case 4: len += 16; break;/* IPv6 address */
1105 case 3: len += (unsigned char)data[4]; break; /* domain name */
1107 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1108 "unrecognised address format",
1109 PROXY_ERROR_GENERAL, 0);
1112 if (bufchain_size(&p->pending_input_data) < len)
1113 return 1; /* not got whole reply yet */
1114 bufchain_consume(&p->pending_input_data, len);
1121 if (p->state == 4) {
1122 /* TODO: Handle GSSAPI authentication */
1123 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1124 PROXY_ERROR_GENERAL, 0);
1128 if (p->state == 5) {
1129 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
1130 char userpwbuf[514];
1132 ulen = strlen(p->cfg.proxy_username);
1133 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1134 plen = strlen(p->cfg.proxy_password);
1135 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1136 userpwbuf[0] = 1; /* version number of subnegotiation */
1137 userpwbuf[1] = ulen;
1138 memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
1139 userpwbuf[ulen+2] = plen;
1140 memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen);
1141 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1144 plug_closing(p->plug, "Proxy error: Server chose "
1145 "username/password authentication but we "
1147 PROXY_ERROR_GENERAL, 0);
1151 if (p->state == 6) {
1152 /* TODO: Handle CHAP authentication */
1153 plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
1154 PROXY_ERROR_GENERAL, 0);
1160 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1161 PROXY_ERROR_UNEXPECTED, 0);
1165 /* ----------------------------------------------------------------------
1166 * `Telnet' proxy type.
1168 * (This is for ad-hoc proxies where you connect to the proxy's
1169 * telnet port and send a command such as `connect host port'. The
1170 * command is configurable, since this proxy type is typically not
1171 * standardised or at all well-defined.)
1174 char *format_telnet_command(SockAddr addr, int port, const Config *cfg)
1177 int retlen = 0, retsize = 0;
1179 #define ENSURE(n) do { \
1180 if (retsize < retlen + n) { \
1181 retsize = retlen + n + 512; \
1182 ret = sresize(ret, retsize, char); \
1186 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1187 * %%, %host, %port, %user, and %pass
1190 while (cfg->proxy_telnet_command[eo] != 0) {
1192 /* scan forward until we hit end-of-line,
1193 * or an escape character (\ or %) */
1194 while (cfg->proxy_telnet_command[eo] != 0 &&
1195 cfg->proxy_telnet_command[eo] != '%' &&
1196 cfg->proxy_telnet_command[eo] != '\\') eo++;
1198 /* if we hit eol, break out of our escaping loop */
1199 if (cfg->proxy_telnet_command[eo] == 0) break;
1201 /* if there was any unescaped text before the escape
1202 * character, send that now */
1205 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1211 /* if the escape character was the last character of
1212 * the line, we'll just stop and send it. */
1213 if (cfg->proxy_telnet_command[eo] == 0) break;
1215 if (cfg->proxy_telnet_command[so] == '\\') {
1217 /* we recognize \\, \%, \r, \n, \t, \x??.
1218 * anything else, we just send unescaped (including the \).
1221 switch (cfg->proxy_telnet_command[eo]) {
1225 ret[retlen++] = '\\';
1231 ret[retlen++] = '%';
1237 ret[retlen++] = '\r';
1243 ret[retlen++] = '\n';
1249 ret[retlen++] = '\t';
1256 /* escaped hexadecimal value (ie. \xff) */
1257 unsigned char v = 0;
1262 if (cfg->proxy_telnet_command[eo] >= '0' &&
1263 cfg->proxy_telnet_command[eo] <= '9')
1264 v += cfg->proxy_telnet_command[eo] - '0';
1265 else if (cfg->proxy_telnet_command[eo] >= 'a' &&
1266 cfg->proxy_telnet_command[eo] <= 'f')
1267 v += cfg->proxy_telnet_command[eo] - 'a' + 10;
1268 else if (cfg->proxy_telnet_command[eo] >= 'A' &&
1269 cfg->proxy_telnet_command[eo] <= 'F')
1270 v += cfg->proxy_telnet_command[eo] - 'A' + 10;
1272 /* non hex character, so we abort and just
1273 * send the whole thing unescaped (including \x)
1276 ret[retlen++] = '\\';
1281 /* we only extract two hex characters */
1297 memcpy(ret+retlen, cfg->proxy_telnet_command + so, 2);
1304 /* % escape. we recognize %%, %host, %port, %user, %pass.
1305 * anything else, we just send unescaped (including the %).
1308 if (cfg->proxy_telnet_command[eo] == '%') {
1310 ret[retlen++] = '%';
1313 else if (strnicmp(cfg->proxy_telnet_command + eo,
1317 sk_getaddr(addr, dest, lenof(dest));
1318 destlen = strlen(dest);
1320 memcpy(ret+retlen, dest, destlen);
1324 else if (strnicmp(cfg->proxy_telnet_command + eo,
1326 char portstr[8], portlen;
1327 portlen = sprintf(portstr, "%i", port);
1329 memcpy(ret + retlen, portstr, portlen);
1333 else if (strnicmp(cfg->proxy_telnet_command + eo,
1335 int userlen = strlen(cfg->proxy_username);
1337 memcpy(ret+retlen, cfg->proxy_username, userlen);
1341 else if (strnicmp(cfg->proxy_telnet_command + eo,
1343 int passlen = strlen(cfg->proxy_password);
1345 memcpy(ret+retlen, cfg->proxy_password, passlen);
1350 /* we don't escape this, so send the % now, and
1351 * don't advance eo, so that we'll consider the
1352 * text immediately following the % as unescaped.
1355 ret[retlen++] = '%';
1359 /* resume scanning for additional escapes after this one. */
1363 /* if there is any unescaped text at the end of the line, send it */
1366 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1377 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1379 if (p->state == PROXY_CHANGE_NEW) {
1380 char *formatted_cmd;
1382 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1385 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1386 sfree(formatted_cmd);
1392 if (change == PROXY_CHANGE_CLOSING) {
1393 /* if our proxy negotiation process involves closing and opening
1394 * new sockets, then we would want to intercept this closing
1395 * callback when we were expecting it. if we aren't anticipating
1396 * a socket close, then some error must have occurred. we'll
1397 * just pass those errors up to the backend.
1399 return plug_closing(p->plug, p->closing_error_msg,
1400 p->closing_error_code,
1401 p->closing_calling_back);
1404 if (change == PROXY_CHANGE_SENT) {
1405 /* some (or all) of what we wrote to the proxy was sent.
1406 * we don't do anything new, however, until we receive the
1407 * proxy's response. we might want to set a timer so we can
1408 * timeout the proxy negotiation after a while...
1413 if (change == PROXY_CHANGE_ACCEPTING) {
1414 /* we should _never_ see this, as we are using our socket to
1415 * connect to a proxy, not accepting inbound connections.
1416 * what should we do? close the socket with an appropriate
1419 return plug_accepting(p->plug, p->accepting_sock);
1422 if (change == PROXY_CHANGE_RECEIVE) {
1423 /* we have received data from the underlying socket, which
1424 * we'll need to parse, process, and respond to appropriately.
1429 /* proxy activate will have dealt with
1430 * whatever is left of the buffer */
1434 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1435 PROXY_ERROR_UNEXPECTED, 0);