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);
96 static int sk_proxy_write (Socket s, const char *data, int len)
98 Proxy_Socket ps = (Proxy_Socket) s;
100 if (ps->state != PROXY_STATE_ACTIVE) {
101 bufchain_add(&ps->pending_output_data, data, len);
102 return bufchain_size(&ps->pending_output_data);
104 return sk_write(ps->sub_socket, data, len);
107 static int sk_proxy_write_oob (Socket s, const char *data, int len)
109 Proxy_Socket ps = (Proxy_Socket) s;
111 if (ps->state != PROXY_STATE_ACTIVE) {
112 bufchain_clear(&ps->pending_output_data);
113 bufchain_clear(&ps->pending_oob_output_data);
114 bufchain_add(&ps->pending_oob_output_data, data, len);
117 return sk_write_oob(ps->sub_socket, data, len);
120 static void sk_proxy_flush (Socket s)
122 Proxy_Socket ps = (Proxy_Socket) s;
124 if (ps->state != PROXY_STATE_ACTIVE) {
125 ps->pending_flush = 1;
128 sk_flush(ps->sub_socket);
131 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
133 Proxy_Socket ps = (Proxy_Socket) s;
134 sk_set_private_ptr(ps->sub_socket, ptr);
137 static void * sk_proxy_get_private_ptr (Socket s)
139 Proxy_Socket ps = (Proxy_Socket) s;
140 return sk_get_private_ptr(ps->sub_socket);
143 static void sk_proxy_set_frozen (Socket s, int is_frozen)
145 Proxy_Socket ps = (Proxy_Socket) s;
147 if (ps->state != PROXY_STATE_ACTIVE) {
148 ps->freeze = is_frozen;
152 /* handle any remaining buffered recv data first */
153 if (bufchain_size(&ps->pending_input_data) > 0) {
154 ps->freeze = is_frozen;
156 /* loop while we still have buffered data, and while we are
157 * unfrozen. the plug_receive call in the loop could result
158 * in a call back into this function refreezing the socket,
159 * so we have to check each time.
161 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
164 bufchain_prefix(&ps->pending_input_data, &data, &len);
165 plug_receive(ps->plug, 0, data, len);
166 bufchain_consume(&ps->pending_input_data, len);
169 /* if we're still frozen, we'll have to wait for another
170 * call from the backend to finish unbuffering the data.
172 if (ps->freeze) return;
175 sk_set_frozen(ps->sub_socket, is_frozen);
178 static const char * sk_proxy_socket_error (Socket s)
180 Proxy_Socket ps = (Proxy_Socket) s;
181 if (ps->error != NULL || ps->sub_socket == NULL) {
184 return sk_socket_error(ps->sub_socket);
187 /* basic proxy plug functions */
189 static int plug_proxy_closing (Plug p, const char *error_msg,
190 int error_code, int calling_back)
192 Proxy_Plug pp = (Proxy_Plug) p;
193 Proxy_Socket ps = pp->proxy_socket;
195 if (ps->state != PROXY_STATE_ACTIVE) {
196 ps->closing_error_msg = error_msg;
197 ps->closing_error_code = error_code;
198 ps->closing_calling_back = calling_back;
199 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
201 return plug_closing(ps->plug, error_msg,
202 error_code, calling_back);
205 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
207 Proxy_Plug pp = (Proxy_Plug) p;
208 Proxy_Socket ps = pp->proxy_socket;
210 if (ps->state != PROXY_STATE_ACTIVE) {
211 /* we will lose the urgentness of this data, but since most,
212 * if not all, of this data will be consumed by the negotiation
213 * process, hopefully it won't affect the protocol above us
215 bufchain_add(&ps->pending_input_data, data, len);
216 ps->receive_urgent = urgent;
217 ps->receive_data = data;
218 ps->receive_len = len;
219 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
221 return plug_receive(ps->plug, urgent, data, len);
224 static void plug_proxy_sent (Plug p, int bufsize)
226 Proxy_Plug pp = (Proxy_Plug) p;
227 Proxy_Socket ps = pp->proxy_socket;
229 if (ps->state != PROXY_STATE_ACTIVE) {
230 ps->sent_bufsize = bufsize;
231 ps->negotiate(ps, PROXY_CHANGE_SENT);
234 plug_sent(ps->plug, bufsize);
237 static int plug_proxy_accepting (Plug p, OSSocket sock)
239 Proxy_Plug pp = (Proxy_Plug) p;
240 Proxy_Socket ps = pp->proxy_socket;
242 if (ps->state != PROXY_STATE_ACTIVE) {
243 ps->accepting_sock = sock;
244 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
246 return plug_accepting(ps->plug, sock);
250 * This function can accept a NULL pointer as `addr', in which case
251 * it will only check the host name.
253 static int proxy_for_destination (SockAddr addr, char *hostname, int port,
258 int hostip_len, hostname_len;
259 const char *exclude_list;
262 * Check the host name and IP against the hard-coded
263 * representations of `localhost'.
265 if (!cfg->even_proxy_localhost &&
266 (sk_hostname_is_local(hostname) ||
267 (addr && sk_address_is_local(addr))))
268 return 0; /* do not proxy */
270 /* we want a string representation of the IP address for comparisons */
272 sk_getaddr(addr, hostip, 64);
273 hostip_len = strlen(hostip);
275 hostip_len = 0; /* placate gcc; shouldn't be required */
277 hostname_len = strlen(hostname);
279 exclude_list = cfg->proxy_exclude_list;
281 /* now parse the exclude list, and see if either our IP
282 * or hostname matches anything in it.
285 while (exclude_list[s]) {
286 while (exclude_list[s] &&
287 (isspace((unsigned char)exclude_list[s]) ||
288 exclude_list[s] == ',')) s++;
290 if (!exclude_list[s]) break;
294 while (exclude_list[e] &&
295 (isalnum((unsigned char)exclude_list[e]) ||
296 exclude_list[e] == '-' ||
297 exclude_list[e] == '.' ||
298 exclude_list[e] == '*')) e++;
300 if (exclude_list[s] == '*') {
301 /* wildcard at beginning of entry */
303 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
304 exclude_list + s + 1, e - s - 1) == 0) ||
305 strnicmp(hostname + hostname_len - (e - s - 1),
306 exclude_list + s + 1, e - s - 1) == 0)
307 return 0; /* IP/hostname range excluded. do not use proxy. */
309 } else if (exclude_list[e-1] == '*') {
310 /* wildcard at end of entry */
312 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
313 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
314 return 0; /* IP/hostname range excluded. do not use proxy. */
317 /* no wildcard at either end, so let's try an absolute
318 * match (ie. a specific IP)
321 if (addr && stricmp(hostip, exclude_list + s) == 0)
322 return 0; /* IP/hostname excluded. do not use proxy. */
323 if (stricmp(hostname, exclude_list + s) == 0)
324 return 0; /* IP/hostname excluded. do not use proxy. */
329 /* Make sure we really have reached the next comma or end-of-string */
330 while (exclude_list[s] &&
331 !isspace((unsigned char)exclude_list[s]) &&
332 exclude_list[s] != ',') s++;
335 /* no matches in the exclude list, so use the proxy */
339 SockAddr name_lookup(char *host, int port, char **canonicalname,
342 if (cfg->proxy_type != PROXY_NONE &&
344 proxy_for_destination(NULL, host, port, cfg)) {
345 *canonicalname = dupstr(host);
346 return sk_nonamelookup(host);
349 return sk_namelookup(host, canonicalname);
352 Socket platform_new_connection(SockAddr addr, char *hostname,
353 int port, int privport,
354 int oobinline, int nodelay, Plug plug,
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;
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 sk_addr_free(proxy_addr);
453 /* start the proxy negotiation process... */
454 sk_set_frozen(ret->sub_socket, 0);
455 ret->negotiate(ret, PROXY_CHANGE_NEW);
460 /* no proxy, so just return the direct socket */
461 return sk_new(addr, port, privport, oobinline, nodelay, plug);
464 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
467 /* TODO: SOCKS (and potentially others) support inbound
468 * TODO: connections via the proxy. support them.
471 return sk_newlistener(srcaddr, port, plug, local_host_only);
474 /* ----------------------------------------------------------------------
475 * HTTP CONNECT proxy type.
478 static int get_line_end (char * data, int len)
484 if (data[off] == '\n') {
485 /* we have a newline */
488 /* is that the only thing on this line? */
489 if (off <= 2) return off;
491 /* if not, then there is the possibility that this header
492 * continues onto the next line, if it starts with a space
497 data[off+1] != ' ' &&
498 data[off+1] != '\t') return off;
500 /* the line does continue, so we have to keep going
501 * until we see an the header's "real" end of line.
512 int proxy_http_negotiate (Proxy_Socket p, int change)
514 if (p->state == PROXY_STATE_NEW) {
515 /* we are just beginning the proxy negotiate process,
516 * so we'll send off the initial bits of the request.
517 * for this proxy method, it's just a simple HTTP
520 char *buf, dest[512];
522 sk_getaddr(p->remote_addr, dest, lenof(dest));
524 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
525 dest, p->remote_port, dest, p->remote_port);
526 sk_write(p->sub_socket, buf, strlen(buf));
529 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
530 char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
531 char buf2[sizeof(buf)*4/3 + 100];
533 sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
535 sprintf(buf2, "Proxy-Authorization: Basic ");
536 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
537 base64_encode_atom((unsigned char *)(buf+i),
538 (len-i > 3 ? 3 : len-i), buf2+j);
539 strcpy(buf2+j, "\r\n");
540 sk_write(p->sub_socket, buf2, strlen(buf2));
543 sk_write(p->sub_socket, "\r\n", 2);
549 if (change == PROXY_CHANGE_CLOSING) {
550 /* if our proxy negotiation process involves closing and opening
551 * new sockets, then we would want to intercept this closing
552 * callback when we were expecting it. if we aren't anticipating
553 * a socket close, then some error must have occurred. we'll
554 * just pass those errors up to the backend.
556 return plug_closing(p->plug, p->closing_error_msg,
557 p->closing_error_code,
558 p->closing_calling_back);
561 if (change == PROXY_CHANGE_SENT) {
562 /* some (or all) of what we wrote to the proxy was sent.
563 * we don't do anything new, however, until we receive the
564 * proxy's response. we might want to set a timer so we can
565 * timeout the proxy negotiation after a while...
570 if (change == PROXY_CHANGE_ACCEPTING) {
571 /* we should _never_ see this, as we are using our socket to
572 * connect to a proxy, not accepting inbound connections.
573 * what should we do? close the socket with an appropriate
576 return plug_accepting(p->plug, p->accepting_sock);
579 if (change == PROXY_CHANGE_RECEIVE) {
580 /* we have received data from the underlying socket, which
581 * we'll need to parse, process, and respond to appropriately.
590 int min_ver, maj_ver, status;
592 /* get the status line */
593 len = bufchain_size(&p->pending_input_data);
594 assert(len > 0); /* or we wouldn't be here */
595 data = snewn(len, char);
596 bufchain_fetch(&p->pending_input_data, data, len);
598 eol = get_line_end(data, len);
605 /* We can't rely on whether the %n incremented the sscanf return */
606 if (sscanf((char *)data, "HTTP/%i.%i %n",
607 &maj_ver, &min_ver, &status) < 2 || status == -1) {
608 plug_closing(p->plug, "Proxy error: HTTP response was absent",
609 PROXY_ERROR_GENERAL, 0);
614 /* remove the status line from the input buffer. */
615 bufchain_consume(&p->pending_input_data, eol);
616 if (data[status] != '2') {
620 while (eol > status &&
621 (data[eol-1] == '\r' || data[eol-1] == '\n'))
623 buf = dupprintf("Proxy error: %s", data+status);
624 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
637 /* get headers. we're done when we get a
638 * header of length 2, (ie. just "\r\n")
641 len = bufchain_size(&p->pending_input_data);
642 assert(len > 0); /* or we wouldn't be here */
643 data = snewn(len, char);
645 bufchain_fetch(&p->pending_input_data, data, len);
647 eol = get_line_end(datap, len);
654 bufchain_consume(&p->pending_input_data, eol);
657 eol = get_line_end(datap, len);
662 bufchain_consume(&p->pending_input_data, 2);
664 /* proxy activate will have dealt with
665 * whatever is left of the buffer */
675 plug_closing(p->plug, "Proxy error: unexpected proxy error",
676 PROXY_ERROR_UNEXPECTED, 0);
680 /* ----------------------------------------------------------------------
684 /* SOCKS version 4 */
685 int proxy_socks4_negotiate (Proxy_Socket p, int change)
687 if (p->state == PROXY_CHANGE_NEW) {
690 * version number (1 byte) = 4
691 * command code (1 byte)
694 * dest. port (2 bytes) [network order]
695 * dest. address (4 bytes)
696 * user ID (variable length, null terminated string)
699 int length, type, namelen;
700 char *command, addr[4], hostname[512];
702 type = sk_addrtype(p->remote_addr);
703 if (type == ADDRTYPE_IPV6) {
704 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
705 " not support IPv6", PROXY_ERROR_GENERAL, 0);
707 } else if (type == ADDRTYPE_IPV4) {
709 sk_addrcopy(p->remote_addr, addr);
710 } else { /* type == ADDRTYPE_NAME */
711 assert(type == ADDRTYPE_NAME);
712 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
713 namelen = strlen(hostname) + 1; /* include the NUL */
714 addr[0] = addr[1] = addr[2] = 0;
718 length = strlen(p->cfg.proxy_username) + namelen + 9;
719 command = snewn(length, char);
720 strcpy(command + 8, p->cfg.proxy_username);
722 command[0] = 4; /* version 4 */
723 command[1] = 1; /* CONNECT command */
726 command[2] = (char) (p->remote_port >> 8) & 0xff;
727 command[3] = (char) p->remote_port & 0xff;
730 memcpy(command + 4, addr, 4);
733 memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1,
736 sk_write(p->sub_socket, command, length);
743 if (change == PROXY_CHANGE_CLOSING) {
744 /* if our proxy negotiation process involves closing and opening
745 * new sockets, then we would want to intercept this closing
746 * callback when we were expecting it. if we aren't anticipating
747 * a socket close, then some error must have occurred. we'll
748 * just pass those errors up to the backend.
750 return plug_closing(p->plug, p->closing_error_msg,
751 p->closing_error_code,
752 p->closing_calling_back);
755 if (change == PROXY_CHANGE_SENT) {
756 /* some (or all) of what we wrote to the proxy was sent.
757 * we don't do anything new, however, until we receive the
758 * proxy's response. we might want to set a timer so we can
759 * timeout the proxy negotiation after a while...
764 if (change == PROXY_CHANGE_ACCEPTING) {
765 /* we should _never_ see this, as we are using our socket to
766 * connect to a proxy, not accepting inbound connections.
767 * what should we do? close the socket with an appropriate
770 return plug_accepting(p->plug, p->accepting_sock);
773 if (change == PROXY_CHANGE_RECEIVE) {
774 /* we have received data from the underlying socket, which
775 * we'll need to parse, process, and respond to appropriately.
780 * version number (1 byte) = 4
781 * reply code (1 byte)
782 * 90 = request granted
783 * 91 = request rejected or failed
784 * 92 = request rejected due to lack of IDENTD on client
785 * 93 = request rejected due to difference in user ID
786 * (what we sent vs. what IDENTD said)
787 * dest. port (2 bytes)
788 * dest. address (4 bytes)
793 if (bufchain_size(&p->pending_input_data) < 8)
794 return 1; /* not got anything yet */
796 /* get the response */
797 bufchain_fetch(&p->pending_input_data, data, 8);
800 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
801 "unexpected reply code version",
802 PROXY_ERROR_GENERAL, 0);
810 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
811 PROXY_ERROR_GENERAL, 0);
814 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
815 PROXY_ERROR_GENERAL, 0);
819 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
820 PROXY_ERROR_GENERAL, 0);
826 bufchain_consume(&p->pending_input_data, 8);
830 /* proxy activate will have dealt with
831 * whatever is left of the buffer */
836 plug_closing(p->plug, "Proxy error: unexpected proxy error",
837 PROXY_ERROR_UNEXPECTED, 0);
841 /* SOCKS version 5 */
842 int proxy_socks5_negotiate (Proxy_Socket p, int change)
844 if (p->state == PROXY_CHANGE_NEW) {
847 * version number (1 byte) = 5
848 * number of available authentication methods (1 byte)
849 * available authentication methods (1 byte * previous value)
850 * authentication methods:
851 * 0x00 = no authentication
853 * 0x02 = username/password
860 command[0] = 5; /* version 5 */
861 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
862 command[1] = 2; /* two methods supported: */
863 command[2] = 0x00; /* no authentication */
864 command[3] = 0x02; /* username/password */
867 command[1] = 1; /* one methods supported: */
868 command[2] = 0x00; /* no authentication */
872 sk_write(p->sub_socket, command, len);
878 if (change == PROXY_CHANGE_CLOSING) {
879 /* if our proxy negotiation process involves closing and opening
880 * new sockets, then we would want to intercept this closing
881 * callback when we were expecting it. if we aren't anticipating
882 * a socket close, then some error must have occurred. we'll
883 * just pass those errors up to the backend.
885 return plug_closing(p->plug, p->closing_error_msg,
886 p->closing_error_code,
887 p->closing_calling_back);
890 if (change == PROXY_CHANGE_SENT) {
891 /* some (or all) of what we wrote to the proxy was sent.
892 * we don't do anything new, however, until we receive the
893 * proxy's response. we might want to set a timer so we can
894 * timeout the proxy negotiation after a while...
899 if (change == PROXY_CHANGE_ACCEPTING) {
900 /* we should _never_ see this, as we are using our socket to
901 * connect to a proxy, not accepting inbound connections.
902 * what should we do? close the socket with an appropriate
905 return plug_accepting(p->plug, p->accepting_sock);
908 if (change == PROXY_CHANGE_RECEIVE) {
909 /* we have received data from the underlying socket, which
910 * we'll need to parse, process, and respond to appropriately.
916 * version number (1 byte) = 5
917 * authentication method (1 byte)
918 * authentication methods:
919 * 0x00 = no authentication
921 * 0x02 = username/password
923 * 0xff = no acceptable methods
927 if (bufchain_size(&p->pending_input_data) < 2)
928 return 1; /* not got anything yet */
930 /* get the response */
931 bufchain_fetch(&p->pending_input_data, data, 2);
934 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
935 PROXY_ERROR_GENERAL, 0);
939 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
940 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
941 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
942 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
944 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
945 PROXY_ERROR_GENERAL, 0);
948 bufchain_consume(&p->pending_input_data, 2);
953 /* password authentication reply format:
954 * version number (1 bytes) = 1
955 * reply code (1 byte)
961 if (bufchain_size(&p->pending_input_data) < 2)
962 return 1; /* not got anything yet */
964 /* get the response */
965 bufchain_fetch(&p->pending_input_data, data, 2);
968 plug_closing(p->plug, "Proxy error: SOCKS password "
969 "subnegotiation contained wrong version number",
970 PROXY_ERROR_GENERAL, 0);
976 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
977 " password authentication",
978 PROXY_ERROR_GENERAL, 0);
982 bufchain_consume(&p->pending_input_data, 2);
983 p->state = 2; /* now proceed as authenticated */
989 * version number (1 byte) = 5
990 * command code (1 byte)
994 * reserved (1 byte) = 0x00
995 * address type (1 byte)
997 * 3 = domainname (first byte has length, no terminating null)
999 * dest. address (variable)
1000 * dest. port (2 bytes) [network order]
1007 type = sk_addrtype(p->remote_addr);
1008 if (type == ADDRTYPE_IPV4) {
1009 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1010 command[3] = 1; /* IPv4 */
1011 sk_addrcopy(p->remote_addr, command+4);
1012 } else if (type == ADDRTYPE_IPV6) {
1013 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1014 command[3] = 4; /* IPv6 */
1015 sk_addrcopy(p->remote_addr, command+4);
1017 assert(type == ADDRTYPE_NAME);
1019 sk_getaddr(p->remote_addr, command+5, 256);
1020 command[4] = strlen(command+5);
1021 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1024 command[0] = 5; /* version 5 */
1025 command[1] = 1; /* CONNECT command */
1029 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1030 command[len-1] = (char) p->remote_port & 0xff;
1032 sk_write(p->sub_socket, command, len);
1038 if (p->state == 3) {
1041 * version number (1 bytes) = 5
1042 * reply code (1 byte)
1044 * 1 = general SOCKS server failure
1045 * 2 = connection not allowed by ruleset
1046 * 3 = network unreachable
1047 * 4 = host unreachable
1048 * 5 = connection refused
1050 * 7 = command not supported
1051 * 8 = address type not supported
1052 * reserved (1 byte) = x00
1053 * address type (1 byte)
1055 * 3 = domainname (first byte has length, no terminating null)
1057 * server bound address (variable)
1058 * server bound port (2 bytes) [network order]
1063 /* First 5 bytes of packet are enough to tell its length. */
1064 if (bufchain_size(&p->pending_input_data) < 5)
1065 return 1; /* not got anything yet */
1067 /* get the response */
1068 bufchain_fetch(&p->pending_input_data, data, 5);
1071 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1072 PROXY_ERROR_GENERAL, 0);
1079 strcpy(buf, "Proxy error: ");
1082 case 1: strcat(buf, "General SOCKS server failure"); break;
1083 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1084 case 3: strcat(buf, "Network unreachable"); break;
1085 case 4: strcat(buf, "Host unreachable"); break;
1086 case 5: strcat(buf, "Connection refused"); break;
1087 case 6: strcat(buf, "TTL expired"); break;
1088 case 7: strcat(buf, "Command not supported"); break;
1089 case 8: strcat(buf, "Address type not supported"); break;
1090 default: sprintf(buf+strlen(buf),
1091 "Unrecognised SOCKS error code %d",
1095 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1101 * Eat the rest of the reply packet.
1103 len = 6; /* first 4 bytes, last 2 */
1105 case 1: len += 4; break; /* IPv4 address */
1106 case 4: len += 16; break;/* IPv6 address */
1107 case 3: len += (unsigned char)data[4]; break; /* domain name */
1109 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1110 "unrecognised address format",
1111 PROXY_ERROR_GENERAL, 0);
1114 if (bufchain_size(&p->pending_input_data) < len)
1115 return 1; /* not got whole reply yet */
1116 bufchain_consume(&p->pending_input_data, len);
1123 if (p->state == 4) {
1124 /* TODO: Handle GSSAPI authentication */
1125 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1126 PROXY_ERROR_GENERAL, 0);
1130 if (p->state == 5) {
1131 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
1132 char userpwbuf[514];
1134 ulen = strlen(p->cfg.proxy_username);
1135 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1136 plen = strlen(p->cfg.proxy_password);
1137 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1138 userpwbuf[0] = 1; /* version number of subnegotiation */
1139 userpwbuf[1] = ulen;
1140 memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
1141 userpwbuf[ulen+2] = plen;
1142 memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen);
1143 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1146 plug_closing(p->plug, "Proxy error: Server chose "
1147 "username/password authentication but we "
1149 PROXY_ERROR_GENERAL, 0);
1153 if (p->state == 6) {
1154 /* TODO: Handle CHAP authentication */
1155 plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
1156 PROXY_ERROR_GENERAL, 0);
1162 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1163 PROXY_ERROR_UNEXPECTED, 0);
1167 /* ----------------------------------------------------------------------
1168 * `Telnet' proxy type.
1170 * (This is for ad-hoc proxies where you connect to the proxy's
1171 * telnet port and send a command such as `connect host port'. The
1172 * command is configurable, since this proxy type is typically not
1173 * standardised or at all well-defined.)
1176 char *format_telnet_command(SockAddr addr, int port, const Config *cfg)
1179 int retlen = 0, retsize = 0;
1181 #define ENSURE(n) do { \
1182 if (retsize < retlen + n) { \
1183 retsize = retlen + n + 512; \
1184 ret = sresize(ret, retsize, char); \
1188 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1189 * %%, %host, %port, %user, and %pass
1192 while (cfg->proxy_telnet_command[eo] != 0) {
1194 /* scan forward until we hit end-of-line,
1195 * or an escape character (\ or %) */
1196 while (cfg->proxy_telnet_command[eo] != 0 &&
1197 cfg->proxy_telnet_command[eo] != '%' &&
1198 cfg->proxy_telnet_command[eo] != '\\') eo++;
1200 /* if we hit eol, break out of our escaping loop */
1201 if (cfg->proxy_telnet_command[eo] == 0) break;
1203 /* if there was any unescaped text before the escape
1204 * character, send that now */
1207 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1213 /* if the escape character was the last character of
1214 * the line, we'll just stop and send it. */
1215 if (cfg->proxy_telnet_command[eo] == 0) break;
1217 if (cfg->proxy_telnet_command[so] == '\\') {
1219 /* we recognize \\, \%, \r, \n, \t, \x??.
1220 * anything else, we just send unescaped (including the \).
1223 switch (cfg->proxy_telnet_command[eo]) {
1227 ret[retlen++] = '\\';
1233 ret[retlen++] = '%';
1239 ret[retlen++] = '\r';
1245 ret[retlen++] = '\n';
1251 ret[retlen++] = '\t';
1258 /* escaped hexadecimal value (ie. \xff) */
1259 unsigned char v = 0;
1264 if (cfg->proxy_telnet_command[eo] >= '0' &&
1265 cfg->proxy_telnet_command[eo] <= '9')
1266 v += cfg->proxy_telnet_command[eo] - '0';
1267 else if (cfg->proxy_telnet_command[eo] >= 'a' &&
1268 cfg->proxy_telnet_command[eo] <= 'f')
1269 v += cfg->proxy_telnet_command[eo] - 'a' + 10;
1270 else if (cfg->proxy_telnet_command[eo] >= 'A' &&
1271 cfg->proxy_telnet_command[eo] <= 'F')
1272 v += cfg->proxy_telnet_command[eo] - 'A' + 10;
1274 /* non hex character, so we abort and just
1275 * send the whole thing unescaped (including \x)
1278 ret[retlen++] = '\\';
1283 /* we only extract two hex characters */
1299 memcpy(ret+retlen, cfg->proxy_telnet_command + so, 2);
1306 /* % escape. we recognize %%, %host, %port, %user, %pass.
1307 * anything else, we just send unescaped (including the %).
1310 if (cfg->proxy_telnet_command[eo] == '%') {
1312 ret[retlen++] = '%';
1315 else if (strnicmp(cfg->proxy_telnet_command + eo,
1319 sk_getaddr(addr, dest, lenof(dest));
1320 destlen = strlen(dest);
1322 memcpy(ret+retlen, dest, destlen);
1326 else if (strnicmp(cfg->proxy_telnet_command + eo,
1328 char portstr[8], portlen;
1329 portlen = sprintf(portstr, "%i", port);
1331 memcpy(ret + retlen, portstr, portlen);
1335 else if (strnicmp(cfg->proxy_telnet_command + eo,
1337 int userlen = strlen(cfg->proxy_username);
1339 memcpy(ret+retlen, cfg->proxy_username, userlen);
1343 else if (strnicmp(cfg->proxy_telnet_command + eo,
1345 int passlen = strlen(cfg->proxy_password);
1347 memcpy(ret+retlen, cfg->proxy_password, passlen);
1352 /* we don't escape this, so send the % now, and
1353 * don't advance eo, so that we'll consider the
1354 * text immediately following the % as unescaped.
1357 ret[retlen++] = '%';
1361 /* resume scanning for additional escapes after this one. */
1365 /* if there is any unescaped text at the end of the line, send it */
1368 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1379 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1381 if (p->state == PROXY_CHANGE_NEW) {
1382 char *formatted_cmd;
1384 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1387 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1388 sfree(formatted_cmd);
1394 if (change == PROXY_CHANGE_CLOSING) {
1395 /* if our proxy negotiation process involves closing and opening
1396 * new sockets, then we would want to intercept this closing
1397 * callback when we were expecting it. if we aren't anticipating
1398 * a socket close, then some error must have occurred. we'll
1399 * just pass those errors up to the backend.
1401 return plug_closing(p->plug, p->closing_error_msg,
1402 p->closing_error_code,
1403 p->closing_calling_back);
1406 if (change == PROXY_CHANGE_SENT) {
1407 /* some (or all) of what we wrote to the proxy was sent.
1408 * we don't do anything new, however, until we receive the
1409 * proxy's response. we might want to set a timer so we can
1410 * timeout the proxy negotiation after a while...
1415 if (change == PROXY_CHANGE_ACCEPTING) {
1416 /* we should _never_ see this, as we are using our socket to
1417 * connect to a proxy, not accepting inbound connections.
1418 * what should we do? close the socket with an appropriate
1421 return plug_accepting(p->plug, p->accepting_sock);
1424 if (change == PROXY_CHANGE_RECEIVE) {
1425 /* we have received data from the underlying socket, which
1426 * we'll need to parse, process, and respond to appropriately.
1431 /* proxy activate will have dealt with
1432 * whatever is left of the buffer */
1436 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1437 PROXY_ERROR_UNEXPECTED, 0);