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 && strnicmp(hostip, exclude_list + s, e - s) == 0)
322 return 0; /* IP/hostname excluded. do not use proxy. */
323 if (strnicmp(hostname, exclude_list + s, e - 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 new_connection(SockAddr addr, char *hostname,
353 int port, int privport,
354 int oobinline, int nodelay, Plug plug,
357 static const struct socket_function_table socket_fn_table = {
363 sk_proxy_set_private_ptr,
364 sk_proxy_get_private_ptr,
366 sk_proxy_socket_error
369 static const struct plug_function_table plug_fn_table = {
376 if (cfg->proxy_type != PROXY_NONE &&
377 proxy_for_destination(addr, hostname, port, cfg))
382 char *proxy_canonical_name;
385 if ((sret = platform_new_connection(addr, hostname, port, privport,
386 oobinline, nodelay, plug, cfg)) !=
390 ret = snew(struct Socket_proxy_tag);
391 ret->fn = &socket_fn_table;
392 ret->cfg = *cfg; /* STRUCTURE COPY */
394 ret->remote_addr = addr;
395 ret->remote_port = port;
398 ret->pending_flush = 0;
401 bufchain_init(&ret->pending_input_data);
402 bufchain_init(&ret->pending_output_data);
403 bufchain_init(&ret->pending_oob_output_data);
405 ret->sub_socket = NULL;
406 ret->state = PROXY_STATE_NEW;
407 ret->negotiate = NULL;
409 if (cfg->proxy_type == PROXY_HTTP) {
410 ret->negotiate = proxy_http_negotiate;
411 } else if (cfg->proxy_type == PROXY_SOCKS4) {
412 ret->negotiate = proxy_socks4_negotiate;
413 } else if (cfg->proxy_type == PROXY_SOCKS5) {
414 ret->negotiate = proxy_socks5_negotiate;
415 } else if (cfg->proxy_type == PROXY_TELNET) {
416 ret->negotiate = proxy_telnet_negotiate;
418 ret->error = "Proxy error: Unknown proxy method";
422 /* create the proxy plug to map calls from the actual
423 * socket into our proxy socket layer */
424 pplug = snew(struct Plug_proxy_tag);
425 pplug->fn = &plug_fn_table;
426 pplug->proxy_socket = ret;
429 proxy_addr = sk_namelookup(cfg->proxy_host,
430 &proxy_canonical_name);
431 if (sk_addr_error(proxy_addr) != NULL) {
432 ret->error = "Proxy error: Unable to resolve proxy host name";
435 sfree(proxy_canonical_name);
437 /* create the actual socket we will be using,
438 * connected to our proxy server and port.
440 ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port,
442 nodelay, (Plug) pplug);
443 if (sk_socket_error(ret->sub_socket) != NULL)
446 sk_addr_free(proxy_addr);
448 /* start the proxy negotiation process... */
449 sk_set_frozen(ret->sub_socket, 0);
450 ret->negotiate(ret, PROXY_CHANGE_NEW);
455 /* no proxy, so just return the direct socket */
456 return sk_new(addr, port, privport, oobinline, nodelay, plug);
459 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
462 /* TODO: SOCKS (and potentially others) support inbound
463 * TODO: connections via the proxy. support them.
466 return sk_newlistener(srcaddr, port, plug, local_host_only);
469 /* ----------------------------------------------------------------------
470 * HTTP CONNECT proxy type.
473 static int get_line_end (char * data, int len)
479 if (data[off] == '\n') {
480 /* we have a newline */
483 /* is that the only thing on this line? */
484 if (off <= 2) return off;
486 /* if not, then there is the possibility that this header
487 * continues onto the next line, if it starts with a space
492 data[off+1] != ' ' &&
493 data[off+1] != '\t') return off;
495 /* the line does continue, so we have to keep going
496 * until we see an the header's "real" end of line.
507 int proxy_http_negotiate (Proxy_Socket p, int change)
509 if (p->state == PROXY_STATE_NEW) {
510 /* we are just beginning the proxy negotiate process,
511 * so we'll send off the initial bits of the request.
512 * for this proxy method, it's just a simple HTTP
515 char *buf, dest[512];
517 sk_getaddr(p->remote_addr, dest, lenof(dest));
519 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
520 dest, p->remote_port, dest, p->remote_port);
521 sk_write(p->sub_socket, buf, strlen(buf));
524 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
525 char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
526 char buf2[sizeof(buf)*4/3 + 100];
528 sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
530 sprintf(buf2, "Proxy-Authorization: Basic ");
531 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
532 base64_encode_atom((unsigned char *)(buf+i),
533 (len-i > 3 ? 3 : len-i), buf2+j);
534 strcpy(buf2+j, "\r\n");
535 sk_write(p->sub_socket, buf2, strlen(buf2));
538 sk_write(p->sub_socket, "\r\n", 2);
544 if (change == PROXY_CHANGE_CLOSING) {
545 /* if our proxy negotiation process involves closing and opening
546 * new sockets, then we would want to intercept this closing
547 * callback when we were expecting it. if we aren't anticipating
548 * a socket close, then some error must have occurred. we'll
549 * just pass those errors up to the backend.
551 return plug_closing(p->plug, p->closing_error_msg,
552 p->closing_error_code,
553 p->closing_calling_back);
556 if (change == PROXY_CHANGE_SENT) {
557 /* some (or all) of what we wrote to the proxy was sent.
558 * we don't do anything new, however, until we receive the
559 * proxy's response. we might want to set a timer so we can
560 * timeout the proxy negotiation after a while...
565 if (change == PROXY_CHANGE_ACCEPTING) {
566 /* we should _never_ see this, as we are using our socket to
567 * connect to a proxy, not accepting inbound connections.
568 * what should we do? close the socket with an appropriate
571 return plug_accepting(p->plug, p->accepting_sock);
574 if (change == PROXY_CHANGE_RECEIVE) {
575 /* we have received data from the underlying socket, which
576 * we'll need to parse, process, and respond to appropriately.
585 int min_ver, maj_ver, status;
587 /* get the status line */
588 len = bufchain_size(&p->pending_input_data);
589 assert(len > 0); /* or we wouldn't be here */
590 data = snewn(len, char);
591 bufchain_fetch(&p->pending_input_data, data, len);
593 eol = get_line_end(data, len);
600 /* We can't rely on whether the %n incremented the sscanf return */
601 if (sscanf((char *)data, "HTTP/%i.%i %n",
602 &maj_ver, &min_ver, &status) < 2 || status == -1) {
603 plug_closing(p->plug, "Proxy error: HTTP response was absent",
604 PROXY_ERROR_GENERAL, 0);
609 /* remove the status line from the input buffer. */
610 bufchain_consume(&p->pending_input_data, eol);
611 if (data[status] != '2') {
615 while (eol > status &&
616 (data[eol-1] == '\r' || data[eol-1] == '\n'))
618 buf = dupprintf("Proxy error: %s", data+status);
619 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
632 /* get headers. we're done when we get a
633 * header of length 2, (ie. just "\r\n")
636 len = bufchain_size(&p->pending_input_data);
637 assert(len > 0); /* or we wouldn't be here */
638 data = snewn(len, char);
640 bufchain_fetch(&p->pending_input_data, data, len);
642 eol = get_line_end(datap, len);
649 bufchain_consume(&p->pending_input_data, eol);
652 eol = get_line_end(datap, len);
657 bufchain_consume(&p->pending_input_data, 2);
659 /* proxy activate will have dealt with
660 * whatever is left of the buffer */
670 plug_closing(p->plug, "Proxy error: unexpected proxy error",
671 PROXY_ERROR_UNEXPECTED, 0);
675 /* ----------------------------------------------------------------------
679 /* SOCKS version 4 */
680 int proxy_socks4_negotiate (Proxy_Socket p, int change)
682 if (p->state == PROXY_CHANGE_NEW) {
685 * version number (1 byte) = 4
686 * command code (1 byte)
689 * dest. port (2 bytes) [network order]
690 * dest. address (4 bytes)
691 * user ID (variable length, null terminated string)
694 int length, type, namelen;
695 char *command, addr[4], hostname[512];
697 type = sk_addrtype(p->remote_addr);
698 if (type == ADDRTYPE_IPV6) {
699 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
700 " not support IPv6", PROXY_ERROR_GENERAL, 0);
702 } else if (type == ADDRTYPE_IPV4) {
704 sk_addrcopy(p->remote_addr, addr);
705 } else { /* type == ADDRTYPE_NAME */
706 assert(type == ADDRTYPE_NAME);
707 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
708 namelen = strlen(hostname) + 1; /* include the NUL */
709 addr[0] = addr[1] = addr[2] = 0;
713 length = strlen(p->cfg.proxy_username) + namelen + 9;
714 command = snewn(length, char);
715 strcpy(command + 8, p->cfg.proxy_username);
717 command[0] = 4; /* version 4 */
718 command[1] = 1; /* CONNECT command */
721 command[2] = (char) (p->remote_port >> 8) & 0xff;
722 command[3] = (char) p->remote_port & 0xff;
725 memcpy(command + 4, addr, 4);
728 memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1,
731 sk_write(p->sub_socket, command, length);
738 if (change == PROXY_CHANGE_CLOSING) {
739 /* if our proxy negotiation process involves closing and opening
740 * new sockets, then we would want to intercept this closing
741 * callback when we were expecting it. if we aren't anticipating
742 * a socket close, then some error must have occurred. we'll
743 * just pass those errors up to the backend.
745 return plug_closing(p->plug, p->closing_error_msg,
746 p->closing_error_code,
747 p->closing_calling_back);
750 if (change == PROXY_CHANGE_SENT) {
751 /* some (or all) of what we wrote to the proxy was sent.
752 * we don't do anything new, however, until we receive the
753 * proxy's response. we might want to set a timer so we can
754 * timeout the proxy negotiation after a while...
759 if (change == PROXY_CHANGE_ACCEPTING) {
760 /* we should _never_ see this, as we are using our socket to
761 * connect to a proxy, not accepting inbound connections.
762 * what should we do? close the socket with an appropriate
765 return plug_accepting(p->plug, p->accepting_sock);
768 if (change == PROXY_CHANGE_RECEIVE) {
769 /* we have received data from the underlying socket, which
770 * we'll need to parse, process, and respond to appropriately.
775 * version number (1 byte) = 4
776 * reply code (1 byte)
777 * 90 = request granted
778 * 91 = request rejected or failed
779 * 92 = request rejected due to lack of IDENTD on client
780 * 93 = request rejected due to difference in user ID
781 * (what we sent vs. what IDENTD said)
782 * dest. port (2 bytes)
783 * dest. address (4 bytes)
788 if (bufchain_size(&p->pending_input_data) < 8)
789 return 1; /* not got anything yet */
791 /* get the response */
792 bufchain_fetch(&p->pending_input_data, data, 8);
795 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
796 "unexpected reply code version",
797 PROXY_ERROR_GENERAL, 0);
805 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
806 PROXY_ERROR_GENERAL, 0);
809 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
810 PROXY_ERROR_GENERAL, 0);
814 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
815 PROXY_ERROR_GENERAL, 0);
821 bufchain_consume(&p->pending_input_data, 8);
825 /* proxy activate will have dealt with
826 * whatever is left of the buffer */
831 plug_closing(p->plug, "Proxy error: unexpected proxy error",
832 PROXY_ERROR_UNEXPECTED, 0);
836 /* SOCKS version 5 */
837 int proxy_socks5_negotiate (Proxy_Socket p, int change)
839 if (p->state == PROXY_CHANGE_NEW) {
842 * version number (1 byte) = 5
843 * number of available authentication methods (1 byte)
844 * available authentication methods (1 byte * previous value)
845 * authentication methods:
846 * 0x00 = no authentication
848 * 0x02 = username/password
855 command[0] = 5; /* version 5 */
856 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
857 command[1] = 2; /* two methods supported: */
858 command[2] = 0x00; /* no authentication */
859 command[3] = 0x02; /* username/password */
862 command[1] = 1; /* one methods supported: */
863 command[2] = 0x00; /* no authentication */
867 sk_write(p->sub_socket, command, len);
873 if (change == PROXY_CHANGE_CLOSING) {
874 /* if our proxy negotiation process involves closing and opening
875 * new sockets, then we would want to intercept this closing
876 * callback when we were expecting it. if we aren't anticipating
877 * a socket close, then some error must have occurred. we'll
878 * just pass those errors up to the backend.
880 return plug_closing(p->plug, p->closing_error_msg,
881 p->closing_error_code,
882 p->closing_calling_back);
885 if (change == PROXY_CHANGE_SENT) {
886 /* some (or all) of what we wrote to the proxy was sent.
887 * we don't do anything new, however, until we receive the
888 * proxy's response. we might want to set a timer so we can
889 * timeout the proxy negotiation after a while...
894 if (change == PROXY_CHANGE_ACCEPTING) {
895 /* we should _never_ see this, as we are using our socket to
896 * connect to a proxy, not accepting inbound connections.
897 * what should we do? close the socket with an appropriate
900 return plug_accepting(p->plug, p->accepting_sock);
903 if (change == PROXY_CHANGE_RECEIVE) {
904 /* we have received data from the underlying socket, which
905 * we'll need to parse, process, and respond to appropriately.
911 * version number (1 byte) = 5
912 * authentication method (1 byte)
913 * authentication methods:
914 * 0x00 = no authentication
916 * 0x02 = username/password
918 * 0xff = no acceptable methods
922 if (bufchain_size(&p->pending_input_data) < 2)
923 return 1; /* not got anything yet */
925 /* get the response */
926 bufchain_fetch(&p->pending_input_data, data, 2);
929 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
930 PROXY_ERROR_GENERAL, 0);
934 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
935 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
936 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
937 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
939 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
940 PROXY_ERROR_GENERAL, 0);
943 bufchain_consume(&p->pending_input_data, 2);
948 /* password authentication reply format:
949 * version number (1 bytes) = 1
950 * reply code (1 byte)
956 if (bufchain_size(&p->pending_input_data) < 2)
957 return 1; /* not got anything yet */
959 /* get the response */
960 bufchain_fetch(&p->pending_input_data, data, 2);
963 plug_closing(p->plug, "Proxy error: SOCKS password "
964 "subnegotiation contained wrong version number",
965 PROXY_ERROR_GENERAL, 0);
971 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
972 " password authentication",
973 PROXY_ERROR_GENERAL, 0);
977 bufchain_consume(&p->pending_input_data, 2);
978 p->state = 2; /* now proceed as authenticated */
984 * version number (1 byte) = 5
985 * command code (1 byte)
989 * reserved (1 byte) = 0x00
990 * address type (1 byte)
992 * 3 = domainname (first byte has length, no terminating null)
994 * dest. address (variable)
995 * dest. port (2 bytes) [network order]
1002 type = sk_addrtype(p->remote_addr);
1003 if (type == ADDRTYPE_IPV4) {
1004 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1005 command[3] = 1; /* IPv4 */
1006 sk_addrcopy(p->remote_addr, command+4);
1007 } else if (type == ADDRTYPE_IPV6) {
1008 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1009 command[3] = 4; /* IPv6 */
1010 sk_addrcopy(p->remote_addr, command+4);
1012 assert(type == ADDRTYPE_NAME);
1014 sk_getaddr(p->remote_addr, command+5, 256);
1015 command[4] = strlen(command+5);
1016 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1019 command[0] = 5; /* version 5 */
1020 command[1] = 1; /* CONNECT command */
1024 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1025 command[len-1] = (char) p->remote_port & 0xff;
1027 sk_write(p->sub_socket, command, len);
1033 if (p->state == 3) {
1036 * version number (1 bytes) = 5
1037 * reply code (1 byte)
1039 * 1 = general SOCKS server failure
1040 * 2 = connection not allowed by ruleset
1041 * 3 = network unreachable
1042 * 4 = host unreachable
1043 * 5 = connection refused
1045 * 7 = command not supported
1046 * 8 = address type not supported
1047 * reserved (1 byte) = x00
1048 * address type (1 byte)
1050 * 3 = domainname (first byte has length, no terminating null)
1052 * server bound address (variable)
1053 * server bound port (2 bytes) [network order]
1058 /* First 5 bytes of packet are enough to tell its length. */
1059 if (bufchain_size(&p->pending_input_data) < 5)
1060 return 1; /* not got anything yet */
1062 /* get the response */
1063 bufchain_fetch(&p->pending_input_data, data, 5);
1066 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1067 PROXY_ERROR_GENERAL, 0);
1074 strcpy(buf, "Proxy error: ");
1077 case 1: strcat(buf, "General SOCKS server failure"); break;
1078 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1079 case 3: strcat(buf, "Network unreachable"); break;
1080 case 4: strcat(buf, "Host unreachable"); break;
1081 case 5: strcat(buf, "Connection refused"); break;
1082 case 6: strcat(buf, "TTL expired"); break;
1083 case 7: strcat(buf, "Command not supported"); break;
1084 case 8: strcat(buf, "Address type not supported"); break;
1085 default: sprintf(buf+strlen(buf),
1086 "Unrecognised SOCKS error code %d",
1090 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1096 * Eat the rest of the reply packet.
1098 len = 6; /* first 4 bytes, last 2 */
1100 case 1: len += 4; break; /* IPv4 address */
1101 case 4: len += 16; break;/* IPv6 address */
1102 case 3: len += (unsigned char)data[4]; break; /* domain name */
1104 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1105 "unrecognised address format",
1106 PROXY_ERROR_GENERAL, 0);
1109 if (bufchain_size(&p->pending_input_data) < len)
1110 return 1; /* not got whole reply yet */
1111 bufchain_consume(&p->pending_input_data, len);
1118 if (p->state == 4) {
1119 /* TODO: Handle GSSAPI authentication */
1120 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1121 PROXY_ERROR_GENERAL, 0);
1125 if (p->state == 5) {
1126 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
1127 char userpwbuf[514];
1129 ulen = strlen(p->cfg.proxy_username);
1130 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1131 plen = strlen(p->cfg.proxy_password);
1132 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1133 userpwbuf[0] = 1; /* version number of subnegotiation */
1134 userpwbuf[1] = ulen;
1135 memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
1136 userpwbuf[ulen+2] = plen;
1137 memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen);
1138 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1141 plug_closing(p->plug, "Proxy error: Server chose "
1142 "username/password authentication but we "
1144 PROXY_ERROR_GENERAL, 0);
1148 if (p->state == 6) {
1149 /* TODO: Handle CHAP authentication */
1150 plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
1151 PROXY_ERROR_GENERAL, 0);
1157 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1158 PROXY_ERROR_UNEXPECTED, 0);
1162 /* ----------------------------------------------------------------------
1163 * `Telnet' proxy type.
1165 * (This is for ad-hoc proxies where you connect to the proxy's
1166 * telnet port and send a command such as `connect host port'. The
1167 * command is configurable, since this proxy type is typically not
1168 * standardised or at all well-defined.)
1171 char *format_telnet_command(SockAddr addr, int port, const Config *cfg)
1174 int retlen = 0, retsize = 0;
1176 #define ENSURE(n) do { \
1177 if (retsize < retlen + n) { \
1178 retsize = retlen + n + 512; \
1179 ret = sresize(ret, retsize, char); \
1183 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1184 * %%, %host, %port, %user, and %pass
1187 while (cfg->proxy_telnet_command[eo] != 0) {
1189 /* scan forward until we hit end-of-line,
1190 * or an escape character (\ or %) */
1191 while (cfg->proxy_telnet_command[eo] != 0 &&
1192 cfg->proxy_telnet_command[eo] != '%' &&
1193 cfg->proxy_telnet_command[eo] != '\\') eo++;
1195 /* if we hit eol, break out of our escaping loop */
1196 if (cfg->proxy_telnet_command[eo] == 0) break;
1198 /* if there was any unescaped text before the escape
1199 * character, send that now */
1202 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1208 /* if the escape character was the last character of
1209 * the line, we'll just stop and send it. */
1210 if (cfg->proxy_telnet_command[eo] == 0) break;
1212 if (cfg->proxy_telnet_command[so] == '\\') {
1214 /* we recognize \\, \%, \r, \n, \t, \x??.
1215 * anything else, we just send unescaped (including the \).
1218 switch (cfg->proxy_telnet_command[eo]) {
1222 ret[retlen++] = '\\';
1228 ret[retlen++] = '%';
1234 ret[retlen++] = '\r';
1240 ret[retlen++] = '\n';
1246 ret[retlen++] = '\t';
1253 /* escaped hexadecimal value (ie. \xff) */
1254 unsigned char v = 0;
1259 if (cfg->proxy_telnet_command[eo] >= '0' &&
1260 cfg->proxy_telnet_command[eo] <= '9')
1261 v += cfg->proxy_telnet_command[eo] - '0';
1262 else if (cfg->proxy_telnet_command[eo] >= 'a' &&
1263 cfg->proxy_telnet_command[eo] <= 'f')
1264 v += cfg->proxy_telnet_command[eo] - 'a' + 10;
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;
1269 /* non hex character, so we abort and just
1270 * send the whole thing unescaped (including \x)
1273 ret[retlen++] = '\\';
1278 /* we only extract two hex characters */
1294 memcpy(ret+retlen, cfg->proxy_telnet_command + so, 2);
1301 /* % escape. we recognize %%, %host, %port, %user, %pass.
1302 * anything else, we just send unescaped (including the %).
1305 if (cfg->proxy_telnet_command[eo] == '%') {
1307 ret[retlen++] = '%';
1310 else if (strnicmp(cfg->proxy_telnet_command + eo,
1314 sk_getaddr(addr, dest, lenof(dest));
1315 destlen = strlen(dest);
1317 memcpy(ret+retlen, dest, destlen);
1321 else if (strnicmp(cfg->proxy_telnet_command + eo,
1323 char portstr[8], portlen;
1324 portlen = sprintf(portstr, "%i", port);
1326 memcpy(ret + retlen, portstr, portlen);
1330 else if (strnicmp(cfg->proxy_telnet_command + eo,
1332 int userlen = strlen(cfg->proxy_username);
1334 memcpy(ret+retlen, cfg->proxy_username, userlen);
1338 else if (strnicmp(cfg->proxy_telnet_command + eo,
1340 int passlen = strlen(cfg->proxy_password);
1342 memcpy(ret+retlen, cfg->proxy_password, passlen);
1347 /* we don't escape this, so send the % now, and
1348 * don't advance eo, so that we'll consider the
1349 * text immediately following the % as unescaped.
1352 ret[retlen++] = '%';
1356 /* resume scanning for additional escapes after this one. */
1360 /* if there is any unescaped text at the end of the line, send it */
1363 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1374 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1376 if (p->state == PROXY_CHANGE_NEW) {
1377 char *formatted_cmd;
1379 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1382 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1383 sfree(formatted_cmd);
1389 if (change == PROXY_CHANGE_CLOSING) {
1390 /* if our proxy negotiation process involves closing and opening
1391 * new sockets, then we would want to intercept this closing
1392 * callback when we were expecting it. if we aren't anticipating
1393 * a socket close, then some error must have occurred. we'll
1394 * just pass those errors up to the backend.
1396 return plug_closing(p->plug, p->closing_error_msg,
1397 p->closing_error_code,
1398 p->closing_calling_back);
1401 if (change == PROXY_CHANGE_SENT) {
1402 /* some (or all) of what we wrote to the proxy was sent.
1403 * we don't do anything new, however, until we receive the
1404 * proxy's response. we might want to set a timer so we can
1405 * timeout the proxy negotiation after a while...
1410 if (change == PROXY_CHANGE_ACCEPTING) {
1411 /* we should _never_ see this, as we are using our socket to
1412 * connect to a proxy, not accepting inbound connections.
1413 * what should we do? close the socket with an appropriate
1416 return plug_accepting(p->plug, p->accepting_sock);
1419 if (change == PROXY_CHANGE_RECEIVE) {
1420 /* we have received data from the underlying socket, which
1421 * we'll need to parse, process, and respond to appropriately.
1426 /* proxy activate will have dealt with
1427 * whatever is left of the buffer */
1431 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1432 PROXY_ERROR_UNEXPECTED, 0);