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 == 2 || \
19 (cfg->proxy_dns == 1 && cfg->proxy_type != PROXY_SOCKS))
22 * Call this when proxy negotiation is complete, so that this
23 * socket can begin working normally.
25 void proxy_activate (Proxy_Socket p)
29 long output_before, output_after;
31 p->state = PROXY_STATE_ACTIVE;
33 /* we want to ignore new receive events until we have sent
34 * all of our buffered receive data.
36 sk_set_frozen(p->sub_socket, 1);
38 /* how many bytes of output have we buffered? */
39 output_before = bufchain_size(&p->pending_oob_output_data) +
40 bufchain_size(&p->pending_output_data);
41 /* and keep track of how many bytes do not get sent. */
44 /* send buffered OOB writes */
45 while (bufchain_size(&p->pending_oob_output_data) > 0) {
46 bufchain_prefix(&p->pending_oob_output_data, &data, &len);
47 output_after += sk_write_oob(p->sub_socket, data, len);
48 bufchain_consume(&p->pending_oob_output_data, len);
51 /* send buffered normal writes */
52 while (bufchain_size(&p->pending_output_data) > 0) {
53 bufchain_prefix(&p->pending_output_data, &data, &len);
54 output_after += sk_write(p->sub_socket, data, len);
55 bufchain_consume(&p->pending_output_data, len);
58 /* if we managed to send any data, let the higher levels know. */
59 if (output_after < output_before)
60 plug_sent(p->plug, output_after);
62 /* if we were asked to flush the output during
63 * the proxy negotiation process, do so now.
65 if (p->pending_flush) sk_flush(p->sub_socket);
67 /* if the backend wanted the socket unfrozen, try to unfreeze.
68 * our set_frozen handler will flush buffered receive data before
69 * unfreezing the actual underlying socket.
72 sk_set_frozen((Socket)p, 0);
75 /* basic proxy socket functions */
77 static Plug sk_proxy_plug (Socket s, Plug p)
79 Proxy_Socket ps = (Proxy_Socket) s;
86 static void sk_proxy_close (Socket s)
88 Proxy_Socket ps = (Proxy_Socket) s;
90 sk_close(ps->sub_socket);
94 static int sk_proxy_write (Socket s, const char *data, int len)
96 Proxy_Socket ps = (Proxy_Socket) s;
98 if (ps->state != PROXY_STATE_ACTIVE) {
99 bufchain_add(&ps->pending_output_data, data, len);
100 return bufchain_size(&ps->pending_output_data);
102 return sk_write(ps->sub_socket, data, len);
105 static int sk_proxy_write_oob (Socket s, const char *data, int len)
107 Proxy_Socket ps = (Proxy_Socket) s;
109 if (ps->state != PROXY_STATE_ACTIVE) {
110 bufchain_clear(&ps->pending_output_data);
111 bufchain_clear(&ps->pending_oob_output_data);
112 bufchain_add(&ps->pending_oob_output_data, data, len);
115 return sk_write_oob(ps->sub_socket, data, len);
118 static void sk_proxy_flush (Socket s)
120 Proxy_Socket ps = (Proxy_Socket) s;
122 if (ps->state != PROXY_STATE_ACTIVE) {
123 ps->pending_flush = 1;
126 sk_flush(ps->sub_socket);
129 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
131 Proxy_Socket ps = (Proxy_Socket) s;
132 sk_set_private_ptr(ps->sub_socket, ptr);
135 static void * sk_proxy_get_private_ptr (Socket s)
137 Proxy_Socket ps = (Proxy_Socket) s;
138 return sk_get_private_ptr(ps->sub_socket);
141 static void sk_proxy_set_frozen (Socket s, int is_frozen)
143 Proxy_Socket ps = (Proxy_Socket) s;
145 if (ps->state != PROXY_STATE_ACTIVE) {
146 ps->freeze = is_frozen;
150 /* handle any remaining buffered recv data first */
151 if (bufchain_size(&ps->pending_input_data) > 0) {
152 ps->freeze = is_frozen;
154 /* loop while we still have buffered data, and while we are
155 * unfrozen. the plug_receive call in the loop could result
156 * in a call back into this function refreezing the socket,
157 * so we have to check each time.
159 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
162 bufchain_prefix(&ps->pending_input_data, &data, &len);
163 plug_receive(ps->plug, 0, data, len);
164 bufchain_consume(&ps->pending_input_data, len);
167 /* if we're still frozen, we'll have to wait for another
168 * call from the backend to finish unbuffering the data.
170 if (ps->freeze) return;
173 sk_set_frozen(ps->sub_socket, is_frozen);
176 static char * sk_proxy_socket_error (Socket s)
178 Proxy_Socket ps = (Proxy_Socket) s;
179 if (ps->error != NULL || ps->sub_socket == NULL) {
182 return sk_socket_error(ps->sub_socket);
185 /* basic proxy plug functions */
187 static int plug_proxy_closing (Plug p, char *error_msg,
188 int error_code, int calling_back)
190 Proxy_Plug pp = (Proxy_Plug) p;
191 Proxy_Socket ps = pp->proxy_socket;
193 if (ps->state != PROXY_STATE_ACTIVE) {
194 ps->closing_error_msg = error_msg;
195 ps->closing_error_code = error_code;
196 ps->closing_calling_back = calling_back;
197 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
199 return plug_closing(ps->plug, error_msg,
200 error_code, calling_back);
203 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
205 Proxy_Plug pp = (Proxy_Plug) p;
206 Proxy_Socket ps = pp->proxy_socket;
208 if (ps->state != PROXY_STATE_ACTIVE) {
209 /* we will lose the urgentness of this data, but since most,
210 * if not all, of this data will be consumed by the negotiation
211 * process, hopefully it won't affect the protocol above us
213 bufchain_add(&ps->pending_input_data, data, len);
214 ps->receive_urgent = urgent;
215 ps->receive_data = data;
216 ps->receive_len = len;
217 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
219 return plug_receive(ps->plug, urgent, data, len);
222 static void plug_proxy_sent (Plug p, int bufsize)
224 Proxy_Plug pp = (Proxy_Plug) p;
225 Proxy_Socket ps = pp->proxy_socket;
227 if (ps->state != PROXY_STATE_ACTIVE) {
228 ps->sent_bufsize = bufsize;
229 ps->negotiate(ps, PROXY_CHANGE_SENT);
232 plug_sent(ps->plug, bufsize);
235 static int plug_proxy_accepting (Plug p, void *sock)
237 Proxy_Plug pp = (Proxy_Plug) p;
238 Proxy_Socket ps = pp->proxy_socket;
240 if (ps->state != PROXY_STATE_ACTIVE) {
241 ps->accepting_sock = sock;
242 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
244 return plug_accepting(ps->plug, sock);
248 * This function can accept a NULL pointer as `addr', in which case
249 * it will only check the host name.
251 static int proxy_for_destination (SockAddr addr, char *hostname, int port,
256 int hostip_len, hostname_len;
257 const char *exclude_list;
260 * Check the host name and IP against the hard-coded
261 * representations of `localhost'.
263 if (!cfg->even_proxy_localhost &&
264 (sk_hostname_is_local(hostname) ||
265 (addr && sk_address_is_local(addr))))
266 return 0; /* do not proxy */
268 /* we want a string representation of the IP address for comparisons */
270 sk_getaddr(addr, hostip, 64);
271 hostip_len = strlen(hostip);
274 hostname_len = strlen(hostname);
276 exclude_list = cfg->proxy_exclude_list;
278 /* now parse the exclude list, and see if either our IP
279 * or hostname matches anything in it.
282 while (exclude_list[s]) {
283 while (exclude_list[s] &&
284 (isspace(exclude_list[s]) ||
285 exclude_list[s] == ',')) s++;
287 if (!exclude_list[s]) break;
291 while (exclude_list[e] &&
292 (isalnum(exclude_list[e]) ||
293 exclude_list[e] == '-' ||
294 exclude_list[e] == '.' ||
295 exclude_list[e] == '*')) e++;
297 if (exclude_list[s] == '*') {
298 /* wildcard at beginning of entry */
300 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
301 exclude_list + s + 1, e - s - 1) == 0) ||
302 strnicmp(hostname + hostname_len - (e - s - 1),
303 exclude_list + s + 1, e - s - 1) == 0)
304 return 0; /* IP/hostname range excluded. do not use proxy. */
306 } else if (exclude_list[e-1] == '*') {
307 /* wildcard at end of entry */
309 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
310 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
311 return 0; /* IP/hostname range excluded. do not use proxy. */
314 /* no wildcard at either end, so let's try an absolute
315 * match (ie. a specific IP)
318 if (addr && stricmp(hostip, exclude_list + s) == 0)
319 return 0; /* IP/hostname excluded. do not use proxy. */
320 if (stricmp(hostname, exclude_list + s) == 0)
321 return 0; /* IP/hostname excluded. do not use proxy. */
326 /* Make sure we really have reached the next comma or end-of-string */
327 while (exclude_list[s] &&
328 !isspace(exclude_list[s]) &&
329 exclude_list[s] != ',') s++;
332 /* no matches in the exclude list, so use the proxy */
336 SockAddr name_lookup(char *host, int port, char **canonicalname,
339 if (cfg->proxy_type != PROXY_NONE &&
341 proxy_for_destination(NULL, host, port, cfg)) {
342 *canonicalname = dupstr(host);
343 return sk_nonamelookup(host);
346 return sk_namelookup(host, canonicalname);
349 Socket new_connection(SockAddr addr, char *hostname,
350 int port, int privport,
351 int oobinline, int nodelay, Plug plug,
354 static const struct socket_function_table socket_fn_table = {
360 sk_proxy_set_private_ptr,
361 sk_proxy_get_private_ptr,
363 sk_proxy_socket_error
366 static const struct plug_function_table plug_fn_table = {
373 if (cfg->proxy_type != PROXY_NONE &&
374 proxy_for_destination(addr, hostname, port, cfg))
379 char *proxy_canonical_name, *err;
381 ret = smalloc(sizeof(struct Socket_proxy_tag));
382 ret->fn = &socket_fn_table;
383 ret->cfg = *cfg; /* STRUCTURE COPY */
385 ret->remote_addr = addr;
386 ret->remote_port = port;
389 ret->pending_flush = 0;
392 bufchain_init(&ret->pending_input_data);
393 bufchain_init(&ret->pending_output_data);
394 bufchain_init(&ret->pending_oob_output_data);
396 ret->sub_socket = NULL;
397 ret->state = PROXY_STATE_NEW;
398 ret->negotiate = NULL;
400 if (cfg->proxy_type == PROXY_HTTP) {
401 ret->negotiate = proxy_http_negotiate;
402 } else if (cfg->proxy_type == PROXY_SOCKS) {
403 if (cfg->proxy_socks_version == 4)
404 ret->negotiate = proxy_socks4_negotiate;
406 ret->negotiate = proxy_socks5_negotiate;
407 } else if (cfg->proxy_type == PROXY_TELNET) {
408 ret->negotiate = proxy_telnet_negotiate;
410 ret->error = "Proxy error: Unknown proxy method";
414 /* create the proxy plug to map calls from the actual
415 * socket into our proxy socket layer */
416 pplug = smalloc(sizeof(struct Plug_proxy_tag));
417 pplug->fn = &plug_fn_table;
418 pplug->proxy_socket = ret;
421 proxy_addr = sk_namelookup(cfg->proxy_host,
422 &proxy_canonical_name);
423 if ((err = sk_addr_error(proxy_addr)) != NULL) {
424 ret->error = "Proxy error: Unable to resolve proxy host name";
427 sfree(proxy_canonical_name);
429 /* create the actual socket we will be using,
430 * connected to our proxy server and port.
432 ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port,
434 nodelay, (Plug) pplug);
435 if (sk_socket_error(ret->sub_socket) != NULL)
438 sk_addr_free(proxy_addr);
440 /* start the proxy negotiation process... */
441 sk_set_frozen(ret->sub_socket, 0);
442 ret->negotiate(ret, PROXY_CHANGE_NEW);
447 /* no proxy, so just return the direct socket */
448 return sk_new(addr, port, privport, oobinline, nodelay, plug);
451 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
454 /* TODO: SOCKS (and potentially others) support inbound
455 * TODO: connections via the proxy. support them.
458 return sk_newlistener(srcaddr, port, plug, local_host_only);
461 /* ----------------------------------------------------------------------
462 * HTTP CONNECT proxy type.
465 static int get_line_end (char * data, int len)
471 if (data[off] == '\n') {
472 /* we have a newline */
475 /* is that the only thing on this line? */
476 if (off <= 2) return off;
478 /* if not, then there is the possibility that this header
479 * continues onto the next line, if it starts with a space
484 data[off+1] != ' ' &&
485 data[off+1] != '\t') return off;
487 /* the line does continue, so we have to keep going
488 * until we see an the header's "real" end of line.
499 int proxy_http_negotiate (Proxy_Socket p, int change)
501 if (p->state == PROXY_STATE_NEW) {
502 /* we are just beginning the proxy negotiate process,
503 * so we'll send off the initial bits of the request.
504 * for this proxy method, it's just a simple HTTP
507 char *buf, dest[512];
509 sk_getaddr(p->remote_addr, dest, lenof(dest));
511 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
512 dest, p->remote_port, dest, p->remote_port);
513 sk_write(p->sub_socket, buf, strlen(buf));
516 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
517 char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
518 char buf2[sizeof(buf)*4/3 + 100];
520 sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
522 sprintf(buf2, "Proxy-Authorization: basic ");
523 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
524 base64_encode_atom((unsigned char *)(buf+i),
525 (len-i > 3 ? 3 : len-i), buf2+j);
526 strcpy(buf2+j, "\r\n");
527 sk_write(p->sub_socket, buf2, strlen(buf2));
530 sk_write(p->sub_socket, "\r\n", 2);
536 if (change == PROXY_CHANGE_CLOSING) {
537 /* if our proxy negotiation process involves closing and opening
538 * new sockets, then we would want to intercept this closing
539 * callback when we were expecting it. if we aren't anticipating
540 * a socket close, then some error must have occurred. we'll
541 * just pass those errors up to the backend.
543 return plug_closing(p->plug, p->closing_error_msg,
544 p->closing_error_code,
545 p->closing_calling_back);
548 if (change == PROXY_CHANGE_SENT) {
549 /* some (or all) of what we wrote to the proxy was sent.
550 * we don't do anything new, however, until we receive the
551 * proxy's response. we might want to set a timer so we can
552 * timeout the proxy negotiation after a while...
557 if (change == PROXY_CHANGE_ACCEPTING) {
558 /* we should _never_ see this, as we are using our socket to
559 * connect to a proxy, not accepting inbound connections.
560 * what should we do? close the socket with an appropriate
563 return plug_accepting(p->plug, p->accepting_sock);
566 if (change == PROXY_CHANGE_RECEIVE) {
567 /* we have received data from the underlying socket, which
568 * we'll need to parse, process, and respond to appropriately.
577 int min_ver, maj_ver, status;
579 /* get the status line */
580 len = bufchain_size(&p->pending_input_data);
581 assert(len > 0); /* or we wouldn't be here */
583 bufchain_fetch(&p->pending_input_data, data, len);
585 eol = get_line_end(data, len);
592 /* We can't rely on whether the %n incremented the sscanf return */
593 if (sscanf((char *)data, "HTTP/%i.%i %n",
594 &maj_ver, &min_ver, &status) < 2 || status == -1) {
595 plug_closing(p->plug, "Proxy error: HTTP response was absent",
596 PROXY_ERROR_GENERAL, 0);
601 /* remove the status line from the input buffer. */
602 bufchain_consume(&p->pending_input_data, eol);
603 if (data[status] != '2') {
607 while (eol > status &&
608 (data[eol-1] == '\r' || data[eol-1] == '\n'))
610 buf = dupprintf("Proxy error: %s", data+status);
611 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
624 /* get headers. we're done when we get a
625 * header of length 2, (ie. just "\r\n")
628 len = bufchain_size(&p->pending_input_data);
629 assert(len > 0); /* or we wouldn't be here */
632 bufchain_fetch(&p->pending_input_data, data, len);
634 eol = get_line_end(datap, len);
641 bufchain_consume(&p->pending_input_data, eol);
644 eol = get_line_end(datap, len);
649 bufchain_consume(&p->pending_input_data, 2);
651 /* proxy activate will have dealt with
652 * whatever is left of the buffer */
662 plug_closing(p->plug, "Proxy error: unexpected proxy error",
663 PROXY_ERROR_UNEXPECTED, 0);
667 /* ----------------------------------------------------------------------
671 /* SOCKS version 4 */
672 int proxy_socks4_negotiate (Proxy_Socket p, int change)
674 if (p->state == PROXY_CHANGE_NEW) {
677 * version number (1 byte) = 4
678 * command code (1 byte)
681 * dest. port (2 bytes) [network order]
682 * dest. address (4 bytes)
683 * user ID (variable length, null terminated string)
686 int length, type, namelen;
687 char *command, addr[4], hostname[512];
689 type = sk_addrtype(p->remote_addr);
690 if (type == ADDRTYPE_IPV6) {
691 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
692 " not support IPv6", PROXY_ERROR_GENERAL, 0);
694 } else if (type == ADDRTYPE_IPV4) {
696 sk_addrcopy(p->remote_addr, addr);
697 } else { /* type == ADDRTYPE_NAME */
698 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
699 namelen = strlen(hostname) + 1; /* include the NUL */
700 addr[0] = addr[1] = addr[2] = 0;
704 length = strlen(p->cfg.proxy_username) + namelen + 9;
705 command = (char*) smalloc(length);
706 strcpy(command + 8, p->cfg.proxy_username);
708 command[0] = 4; /* version 4 */
709 command[1] = 1; /* CONNECT command */
712 command[2] = (char) (p->remote_port >> 8) & 0xff;
713 command[3] = (char) p->remote_port & 0xff;
716 memcpy(command + 4, addr, 4);
719 memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1,
722 sk_write(p->sub_socket, command, length);
729 if (change == PROXY_CHANGE_CLOSING) {
730 /* if our proxy negotiation process involves closing and opening
731 * new sockets, then we would want to intercept this closing
732 * callback when we were expecting it. if we aren't anticipating
733 * a socket close, then some error must have occurred. we'll
734 * just pass those errors up to the backend.
736 return plug_closing(p->plug, p->closing_error_msg,
737 p->closing_error_code,
738 p->closing_calling_back);
741 if (change == PROXY_CHANGE_SENT) {
742 /* some (or all) of what we wrote to the proxy was sent.
743 * we don't do anything new, however, until we receive the
744 * proxy's response. we might want to set a timer so we can
745 * timeout the proxy negotiation after a while...
750 if (change == PROXY_CHANGE_ACCEPTING) {
751 /* we should _never_ see this, as we are using our socket to
752 * connect to a proxy, not accepting inbound connections.
753 * what should we do? close the socket with an appropriate
756 return plug_accepting(p->plug, p->accepting_sock);
759 if (change == PROXY_CHANGE_RECEIVE) {
760 /* we have received data from the underlying socket, which
761 * we'll need to parse, process, and respond to appropriately.
766 * version number (1 byte) = 4
767 * reply code (1 byte)
768 * 90 = request granted
769 * 91 = request rejected or failed
770 * 92 = request rejected due to lack of IDENTD on client
771 * 93 = request rejected due to difference in user ID
772 * (what we sent vs. what IDENTD said)
773 * dest. port (2 bytes)
774 * dest. address (4 bytes)
779 if (bufchain_size(&p->pending_input_data) < 8)
780 return 1; /* not got anything yet */
782 /* get the response */
783 bufchain_fetch(&p->pending_input_data, data, 8);
786 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
787 "unexpected reply code version",
788 PROXY_ERROR_GENERAL, 0);
796 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
797 PROXY_ERROR_GENERAL, 0);
800 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
801 PROXY_ERROR_GENERAL, 0);
805 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
806 PROXY_ERROR_GENERAL, 0);
812 bufchain_consume(&p->pending_input_data, 8);
816 /* proxy activate will have dealt with
817 * whatever is left of the buffer */
822 plug_closing(p->plug, "Proxy error: unexpected proxy error",
823 PROXY_ERROR_UNEXPECTED, 0);
827 /* SOCKS version 5 */
828 int proxy_socks5_negotiate (Proxy_Socket p, int change)
830 if (p->state == PROXY_CHANGE_NEW) {
833 * version number (1 byte) = 5
834 * number of available authentication methods (1 byte)
835 * available authentication methods (1 byte * previous value)
836 * authentication methods:
837 * 0x00 = no authentication
839 * 0x02 = username/password
846 command[0] = 5; /* version 5 */
847 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
848 command[1] = 2; /* two methods supported: */
849 command[2] = 0x00; /* no authentication */
850 command[3] = 0x02; /* username/password */
853 command[1] = 1; /* one methods supported: */
854 command[2] = 0x00; /* no authentication */
858 sk_write(p->sub_socket, command, len);
864 if (change == PROXY_CHANGE_CLOSING) {
865 /* if our proxy negotiation process involves closing and opening
866 * new sockets, then we would want to intercept this closing
867 * callback when we were expecting it. if we aren't anticipating
868 * a socket close, then some error must have occurred. we'll
869 * just pass those errors up to the backend.
871 return plug_closing(p->plug, p->closing_error_msg,
872 p->closing_error_code,
873 p->closing_calling_back);
876 if (change == PROXY_CHANGE_SENT) {
877 /* some (or all) of what we wrote to the proxy was sent.
878 * we don't do anything new, however, until we receive the
879 * proxy's response. we might want to set a timer so we can
880 * timeout the proxy negotiation after a while...
885 if (change == PROXY_CHANGE_ACCEPTING) {
886 /* we should _never_ see this, as we are using our socket to
887 * connect to a proxy, not accepting inbound connections.
888 * what should we do? close the socket with an appropriate
891 return plug_accepting(p->plug, p->accepting_sock);
894 if (change == PROXY_CHANGE_RECEIVE) {
895 /* we have received data from the underlying socket, which
896 * we'll need to parse, process, and respond to appropriately.
902 * version number (1 byte) = 5
903 * authentication method (1 byte)
904 * authentication methods:
905 * 0x00 = no authentication
907 * 0x02 = username/password
909 * 0xff = no acceptable methods
913 if (bufchain_size(&p->pending_input_data) < 2)
914 return 1; /* not got anything yet */
916 /* get the response */
917 bufchain_fetch(&p->pending_input_data, data, 2);
920 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
921 PROXY_ERROR_GENERAL, 0);
925 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
926 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
927 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
928 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
930 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
931 PROXY_ERROR_GENERAL, 0);
934 bufchain_consume(&p->pending_input_data, 2);
939 /* password authentication reply format:
940 * version number (1 bytes) = 1
941 * reply code (1 byte)
947 if (bufchain_size(&p->pending_input_data) < 2)
948 return 1; /* not got anything yet */
950 /* get the response */
951 bufchain_fetch(&p->pending_input_data, data, 2);
954 plug_closing(p->plug, "Proxy error: SOCKS password "
955 "subnegotiation contained wrong version number",
956 PROXY_ERROR_GENERAL, 0);
962 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
963 " password authentication",
964 PROXY_ERROR_GENERAL, 0);
968 bufchain_consume(&p->pending_input_data, 2);
969 p->state = 2; /* now proceed as authenticated */
975 * version number (1 byte) = 5
976 * command code (1 byte)
980 * reserved (1 byte) = 0x00
981 * address type (1 byte)
983 * 3 = domainname (first byte has length, no terminating null)
985 * dest. address (variable)
986 * dest. port (2 bytes) [network order]
993 type = sk_addrtype(p->remote_addr);
994 if (type == ADDRTYPE_IPV4) {
995 len = 10; /* 4 hdr + 4 addr + 2 trailer */
996 command[3] = 1; /* IPv4 */
997 sk_addrcopy(p->remote_addr, command+4);
998 } else if (type == ADDRTYPE_IPV6) {
999 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1000 command[3] = 4; /* IPv6 */
1001 sk_addrcopy(p->remote_addr, command+4);
1002 } else if (type == ADDRTYPE_NAME) {
1004 sk_getaddr(p->remote_addr, command+5, 256);
1005 command[4] = strlen(command+5);
1006 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1009 command[0] = 5; /* version 5 */
1010 command[1] = 1; /* CONNECT command */
1014 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1015 command[len-1] = (char) p->remote_port & 0xff;
1017 sk_write(p->sub_socket, command, len);
1023 if (p->state == 3) {
1026 * version number (1 bytes) = 5
1027 * reply code (1 byte)
1029 * 1 = general SOCKS server failure
1030 * 2 = connection not allowed by ruleset
1031 * 3 = network unreachable
1032 * 4 = host unreachable
1033 * 5 = connection refused
1035 * 7 = command not supported
1036 * 8 = address type not supported
1037 * reserved (1 byte) = x00
1038 * address type (1 byte)
1040 * 3 = domainname (first byte has length, no terminating null)
1042 * server bound address (variable)
1043 * server bound port (2 bytes) [network order]
1048 /* First 5 bytes of packet are enough to tell its length. */
1049 if (bufchain_size(&p->pending_input_data) < 5)
1050 return 1; /* not got anything yet */
1052 /* get the response */
1053 bufchain_fetch(&p->pending_input_data, data, 5);
1056 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1057 PROXY_ERROR_GENERAL, 0);
1064 strcpy(buf, "Proxy error: ");
1067 case 1: strcat(buf, "General SOCKS server failure"); break;
1068 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1069 case 3: strcat(buf, "Network unreachable"); break;
1070 case 4: strcat(buf, "Host unreachable"); break;
1071 case 5: strcat(buf, "Connection refused"); break;
1072 case 6: strcat(buf, "TTL expired"); break;
1073 case 7: strcat(buf, "Command not supported"); break;
1074 case 8: strcat(buf, "Address type not supported"); break;
1075 default: sprintf(buf+strlen(buf),
1076 "Unrecognised SOCKS error code %d",
1080 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1086 * Eat the rest of the reply packet.
1088 len = 6; /* first 4 bytes, last 2 */
1090 case 1: len += 4; break; /* IPv4 address */
1091 case 4: len += 16; break;/* IPv6 address */
1092 case 3: len += (unsigned char)data[4]; break; /* domain name */
1094 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1095 "unrecognised address format",
1096 PROXY_ERROR_GENERAL, 0);
1099 if (bufchain_size(&p->pending_input_data) < len)
1100 return 1; /* not got whole reply yet */
1101 bufchain_consume(&p->pending_input_data, len);
1108 if (p->state == 4) {
1109 /* TODO: Handle GSSAPI authentication */
1110 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1111 PROXY_ERROR_GENERAL, 0);
1115 if (p->state == 5) {
1116 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
1117 char userpwbuf[514];
1119 ulen = strlen(p->cfg.proxy_username);
1120 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1121 plen = strlen(p->cfg.proxy_password);
1122 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1123 userpwbuf[0] = 1; /* version number of subnegotiation */
1124 userpwbuf[1] = ulen;
1125 memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
1126 userpwbuf[ulen+2] = plen;
1127 memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen);
1128 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1131 plug_closing(p->plug, "Proxy error: Server chose "
1132 "username/password authentication but we "
1134 PROXY_ERROR_GENERAL, 0);
1138 if (p->state == 6) {
1139 /* TODO: Handle CHAP authentication */
1140 plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
1141 PROXY_ERROR_GENERAL, 0);
1147 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1148 PROXY_ERROR_UNEXPECTED, 0);
1152 /* ----------------------------------------------------------------------
1153 * `Telnet' proxy type.
1155 * (This is for ad-hoc proxies where you connect to the proxy's
1156 * telnet port and send a command such as `connect host port'. The
1157 * command is configurable, since this proxy type is typically not
1158 * standardised or at all well-defined.)
1161 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1163 if (p->state == PROXY_CHANGE_NEW) {
1167 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1168 * %%, %host, %port, %user, and %pass
1171 while (p->cfg.proxy_telnet_command[eo] != 0) {
1173 /* scan forward until we hit end-of-line,
1174 * or an escape character (\ or %) */
1175 while (p->cfg.proxy_telnet_command[eo] != 0 &&
1176 p->cfg.proxy_telnet_command[eo] != '%' &&
1177 p->cfg.proxy_telnet_command[eo] != '\\') eo++;
1179 /* if we hit eol, break out of our escaping loop */
1180 if (p->cfg.proxy_telnet_command[eo] == 0) break;
1182 /* if there was any unescaped text before the escape
1183 * character, send that now */
1185 sk_write(p->sub_socket,
1186 p->cfg.proxy_telnet_command + so, eo - so);
1191 /* if the escape character was the last character of
1192 * the line, we'll just stop and send it. */
1193 if (p->cfg.proxy_telnet_command[eo] == 0) break;
1195 if (p->cfg.proxy_telnet_command[so] == '\\') {
1197 /* we recognize \\, \%, \r, \n, \t, \x??.
1198 * anything else, we just send unescaped (including the \).
1201 switch (p->cfg.proxy_telnet_command[eo]) {
1204 sk_write(p->sub_socket, "\\", 1);
1209 sk_write(p->sub_socket, "%%", 1);
1214 sk_write(p->sub_socket, "\r", 1);
1219 sk_write(p->sub_socket, "\n", 1);
1224 sk_write(p->sub_socket, "\t", 1);
1231 /* escaped hexadecimal value (ie. \xff) */
1232 unsigned char v = 0;
1237 if (p->cfg.proxy_telnet_command[eo] >= '0' &&
1238 p->cfg.proxy_telnet_command[eo] <= '9')
1239 v += p->cfg.proxy_telnet_command[eo] - '0';
1240 else if (p->cfg.proxy_telnet_command[eo] >= 'a' &&
1241 p->cfg.proxy_telnet_command[eo] <= 'f')
1242 v += p->cfg.proxy_telnet_command[eo] - 'a' + 10;
1243 else if (p->cfg.proxy_telnet_command[eo] >= 'A' &&
1244 p->cfg.proxy_telnet_command[eo] <= 'F')
1245 v += p->cfg.proxy_telnet_command[eo] - 'A' + 10;
1247 /* non hex character, so we abort and just
1248 * send the whole thing unescaped (including \x)
1250 sk_write(p->sub_socket, "\\", 1);
1255 /* we only extract two hex characters */
1257 sk_write(p->sub_socket, (char *)&v, 1);
1269 sk_write(p->sub_socket,
1270 p->cfg.proxy_telnet_command + so, 2);
1276 /* % escape. we recognize %%, %host, %port, %user, %pass.
1277 * anything else, we just send unescaped (including the %).
1280 if (p->cfg.proxy_telnet_command[eo] == '%') {
1281 sk_write(p->sub_socket, "%", 1);
1284 else if (strnicmp(p->cfg.proxy_telnet_command + eo,
1287 sk_getaddr(p->remote_addr, dest, lenof(dest));
1288 sk_write(p->sub_socket, dest, strlen(dest));
1291 else if (strnicmp(p->cfg.proxy_telnet_command + eo,
1294 sprintf(port, "%i", p->remote_port);
1295 sk_write(p->sub_socket, port, strlen(port));
1298 else if (strnicmp(p->cfg.proxy_telnet_command + eo,
1300 sk_write(p->sub_socket, p->cfg.proxy_username,
1301 strlen(p->cfg.proxy_username));
1304 else if (strnicmp(p->cfg.proxy_telnet_command + eo,
1306 sk_write(p->sub_socket, p->cfg.proxy_password,
1307 strlen(p->cfg.proxy_password));
1311 /* we don't escape this, so send the % now, and
1312 * don't advance eo, so that we'll consider the
1313 * text immediately following the % as unescaped.
1315 sk_write(p->sub_socket, "%", 1);
1319 /* resume scanning for additional escapes after this one. */
1323 /* if there is any unescaped text at the end of the line, send it */
1325 sk_write(p->sub_socket, p->cfg.proxy_telnet_command + so, eo - so);
1332 if (change == PROXY_CHANGE_CLOSING) {
1333 /* if our proxy negotiation process involves closing and opening
1334 * new sockets, then we would want to intercept this closing
1335 * callback when we were expecting it. if we aren't anticipating
1336 * a socket close, then some error must have occurred. we'll
1337 * just pass those errors up to the backend.
1339 return plug_closing(p->plug, p->closing_error_msg,
1340 p->closing_error_code,
1341 p->closing_calling_back);
1344 if (change == PROXY_CHANGE_SENT) {
1345 /* some (or all) of what we wrote to the proxy was sent.
1346 * we don't do anything new, however, until we receive the
1347 * proxy's response. we might want to set a timer so we can
1348 * timeout the proxy negotiation after a while...
1353 if (change == PROXY_CHANGE_ACCEPTING) {
1354 /* we should _never_ see this, as we are using our socket to
1355 * connect to a proxy, not accepting inbound connections.
1356 * what should we do? close the socket with an appropriate
1359 return plug_accepting(p->plug, p->accepting_sock);
1362 if (change == PROXY_CHANGE_RECEIVE) {
1363 /* we have received data from the underlying socket, which
1364 * we'll need to parse, process, and respond to appropriately.
1369 /* proxy activate will have dealt with
1370 * whatever is left of the buffer */
1374 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1375 PROXY_ERROR_UNEXPECTED, 0);