2 * Network proxy abstraction in PuTTY
4 * A proxy layer, if necessary, wedges itself between the network
5 * code and the higher level backend.
12 #define DEFINE_PLUG_METHOD_MACROS
17 #define do_proxy_dns(cfg) \
18 (cfg->proxy_dns == FORCE_ON || \
19 (cfg->proxy_dns == AUTO && \
20 cfg->proxy_type != PROXY_SOCKS4 && \
21 cfg->proxy_type != PROXY_SOCKS5))
24 * Call this when proxy negotiation is complete, so that this
25 * socket can begin working normally.
27 void proxy_activate (Proxy_Socket p)
31 long output_before, output_after;
33 p->state = PROXY_STATE_ACTIVE;
35 /* we want to ignore new receive events until we have sent
36 * all of our buffered receive data.
38 sk_set_frozen(p->sub_socket, 1);
40 /* how many bytes of output have we buffered? */
41 output_before = bufchain_size(&p->pending_oob_output_data) +
42 bufchain_size(&p->pending_output_data);
43 /* and keep track of how many bytes do not get sent. */
46 /* send buffered OOB writes */
47 while (bufchain_size(&p->pending_oob_output_data) > 0) {
48 bufchain_prefix(&p->pending_oob_output_data, &data, &len);
49 output_after += sk_write_oob(p->sub_socket, data, len);
50 bufchain_consume(&p->pending_oob_output_data, len);
53 /* send buffered normal writes */
54 while (bufchain_size(&p->pending_output_data) > 0) {
55 bufchain_prefix(&p->pending_output_data, &data, &len);
56 output_after += sk_write(p->sub_socket, data, len);
57 bufchain_consume(&p->pending_output_data, len);
60 /* if we managed to send any data, let the higher levels know. */
61 if (output_after < output_before)
62 plug_sent(p->plug, output_after);
64 /* if we were asked to flush the output during
65 * the proxy negotiation process, do so now.
67 if (p->pending_flush) sk_flush(p->sub_socket);
69 /* if the backend wanted the socket unfrozen, try to unfreeze.
70 * our set_frozen handler will flush buffered receive data before
71 * unfreezing the actual underlying socket.
74 sk_set_frozen((Socket)p, 0);
77 /* basic proxy socket functions */
79 static Plug sk_proxy_plug (Socket s, Plug p)
81 Proxy_Socket ps = (Proxy_Socket) s;
88 static void sk_proxy_close (Socket s)
90 Proxy_Socket ps = (Proxy_Socket) s;
92 sk_close(ps->sub_socket);
93 sk_addr_free(ps->remote_addr);
97 static int sk_proxy_write (Socket s, const char *data, int len)
99 Proxy_Socket ps = (Proxy_Socket) s;
101 if (ps->state != PROXY_STATE_ACTIVE) {
102 bufchain_add(&ps->pending_output_data, data, len);
103 return bufchain_size(&ps->pending_output_data);
105 return sk_write(ps->sub_socket, data, len);
108 static int sk_proxy_write_oob (Socket s, const char *data, int len)
110 Proxy_Socket ps = (Proxy_Socket) s;
112 if (ps->state != PROXY_STATE_ACTIVE) {
113 bufchain_clear(&ps->pending_output_data);
114 bufchain_clear(&ps->pending_oob_output_data);
115 bufchain_add(&ps->pending_oob_output_data, data, len);
118 return sk_write_oob(ps->sub_socket, data, len);
121 static void sk_proxy_flush (Socket s)
123 Proxy_Socket ps = (Proxy_Socket) s;
125 if (ps->state != PROXY_STATE_ACTIVE) {
126 ps->pending_flush = 1;
129 sk_flush(ps->sub_socket);
132 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
134 Proxy_Socket ps = (Proxy_Socket) s;
135 sk_set_private_ptr(ps->sub_socket, ptr);
138 static void * sk_proxy_get_private_ptr (Socket s)
140 Proxy_Socket ps = (Proxy_Socket) s;
141 return sk_get_private_ptr(ps->sub_socket);
144 static void sk_proxy_set_frozen (Socket s, int is_frozen)
146 Proxy_Socket ps = (Proxy_Socket) s;
148 if (ps->state != PROXY_STATE_ACTIVE) {
149 ps->freeze = is_frozen;
153 /* handle any remaining buffered recv data first */
154 if (bufchain_size(&ps->pending_input_data) > 0) {
155 ps->freeze = is_frozen;
157 /* loop while we still have buffered data, and while we are
158 * unfrozen. the plug_receive call in the loop could result
159 * in a call back into this function refreezing the socket,
160 * so we have to check each time.
162 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
166 bufchain_prefix(&ps->pending_input_data, &data, &len);
167 if (len > lenof(databuf))
168 len = lenof(databuf);
169 memcpy(databuf, data, len);
170 bufchain_consume(&ps->pending_input_data, len);
171 plug_receive(ps->plug, 0, databuf, len);
174 /* if we're still frozen, we'll have to wait for another
175 * call from the backend to finish unbuffering the data.
177 if (ps->freeze) return;
180 sk_set_frozen(ps->sub_socket, is_frozen);
183 static const char * sk_proxy_socket_error (Socket s)
185 Proxy_Socket ps = (Proxy_Socket) s;
186 if (ps->error != NULL || ps->sub_socket == NULL) {
189 return sk_socket_error(ps->sub_socket);
192 /* basic proxy plug functions */
194 static void plug_proxy_log(Plug plug, int type, SockAddr addr, int port,
195 const char *error_msg, int error_code)
197 Proxy_Plug pp = (Proxy_Plug) plug;
198 Proxy_Socket ps = pp->proxy_socket;
200 plug_log(ps->plug, type, addr, port, error_msg, error_code);
203 static int plug_proxy_closing (Plug p, const char *error_msg,
204 int error_code, int calling_back)
206 Proxy_Plug pp = (Proxy_Plug) p;
207 Proxy_Socket ps = pp->proxy_socket;
209 if (ps->state != PROXY_STATE_ACTIVE) {
210 ps->closing_error_msg = error_msg;
211 ps->closing_error_code = error_code;
212 ps->closing_calling_back = calling_back;
213 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
215 return plug_closing(ps->plug, error_msg,
216 error_code, calling_back);
219 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
221 Proxy_Plug pp = (Proxy_Plug) p;
222 Proxy_Socket ps = pp->proxy_socket;
224 if (ps->state != PROXY_STATE_ACTIVE) {
225 /* we will lose the urgentness of this data, but since most,
226 * if not all, of this data will be consumed by the negotiation
227 * process, hopefully it won't affect the protocol above us
229 bufchain_add(&ps->pending_input_data, data, len);
230 ps->receive_urgent = urgent;
231 ps->receive_data = data;
232 ps->receive_len = len;
233 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
235 return plug_receive(ps->plug, urgent, data, len);
238 static void plug_proxy_sent (Plug p, int bufsize)
240 Proxy_Plug pp = (Proxy_Plug) p;
241 Proxy_Socket ps = pp->proxy_socket;
243 if (ps->state != PROXY_STATE_ACTIVE) {
244 ps->sent_bufsize = bufsize;
245 ps->negotiate(ps, PROXY_CHANGE_SENT);
248 plug_sent(ps->plug, bufsize);
251 static int plug_proxy_accepting (Plug p, OSSocket sock)
253 Proxy_Plug pp = (Proxy_Plug) p;
254 Proxy_Socket ps = pp->proxy_socket;
256 if (ps->state != PROXY_STATE_ACTIVE) {
257 ps->accepting_sock = sock;
258 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
260 return plug_accepting(ps->plug, sock);
264 * This function can accept a NULL pointer as `addr', in which case
265 * it will only check the host name.
267 static int proxy_for_destination (SockAddr addr, char *hostname, int port,
272 int hostip_len, hostname_len;
273 const char *exclude_list;
276 * Check the host name and IP against the hard-coded
277 * representations of `localhost'.
279 if (!cfg->even_proxy_localhost &&
280 (sk_hostname_is_local(hostname) ||
281 (addr && sk_address_is_local(addr))))
282 return 0; /* do not proxy */
284 /* we want a string representation of the IP address for comparisons */
286 sk_getaddr(addr, hostip, 64);
287 hostip_len = strlen(hostip);
289 hostip_len = 0; /* placate gcc; shouldn't be required */
291 hostname_len = strlen(hostname);
293 exclude_list = cfg->proxy_exclude_list;
295 /* now parse the exclude list, and see if either our IP
296 * or hostname matches anything in it.
299 while (exclude_list[s]) {
300 while (exclude_list[s] &&
301 (isspace((unsigned char)exclude_list[s]) ||
302 exclude_list[s] == ',')) s++;
304 if (!exclude_list[s]) break;
308 while (exclude_list[e] &&
309 (isalnum((unsigned char)exclude_list[e]) ||
310 exclude_list[e] == '-' ||
311 exclude_list[e] == '.' ||
312 exclude_list[e] == '*')) e++;
314 if (exclude_list[s] == '*') {
315 /* wildcard at beginning of entry */
317 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
318 exclude_list + s + 1, e - s - 1) == 0) ||
319 strnicmp(hostname + hostname_len - (e - s - 1),
320 exclude_list + s + 1, e - s - 1) == 0)
321 return 0; /* IP/hostname range excluded. do not use proxy. */
323 } else if (exclude_list[e-1] == '*') {
324 /* wildcard at end of entry */
326 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
327 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
328 return 0; /* IP/hostname range excluded. do not use proxy. */
331 /* no wildcard at either end, so let's try an absolute
332 * match (ie. a specific IP)
335 if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
336 return 0; /* IP/hostname excluded. do not use proxy. */
337 if (strnicmp(hostname, exclude_list + s, e - s) == 0)
338 return 0; /* IP/hostname excluded. do not use proxy. */
343 /* Make sure we really have reached the next comma or end-of-string */
344 while (exclude_list[s] &&
345 !isspace((unsigned char)exclude_list[s]) &&
346 exclude_list[s] != ',') s++;
349 /* no matches in the exclude list, so use the proxy */
353 SockAddr name_lookup(char *host, int port, char **canonicalname,
354 const Config *cfg, int addressfamily)
356 if (cfg->proxy_type != PROXY_NONE &&
358 proxy_for_destination(NULL, host, port, cfg)) {
359 *canonicalname = dupstr(host);
360 return sk_nonamelookup(host);
363 return sk_namelookup(host, canonicalname, addressfamily);
366 Socket new_connection(SockAddr addr, char *hostname,
367 int port, int privport,
368 int oobinline, int nodelay, int keepalive,
369 Plug plug, const Config *cfg)
371 static const struct socket_function_table socket_fn_table = {
377 sk_proxy_set_private_ptr,
378 sk_proxy_get_private_ptr,
380 sk_proxy_socket_error
383 static const struct plug_function_table plug_fn_table = {
391 if (cfg->proxy_type != PROXY_NONE &&
392 proxy_for_destination(addr, hostname, port, cfg))
397 char *proxy_canonical_name;
400 if ((sret = platform_new_connection(addr, hostname, port, privport,
401 oobinline, nodelay, keepalive,
406 ret = snew(struct Socket_proxy_tag);
407 ret->fn = &socket_fn_table;
408 ret->cfg = *cfg; /* STRUCTURE COPY */
410 ret->remote_addr = addr; /* will need to be freed on close */
411 ret->remote_port = port;
414 ret->pending_flush = 0;
417 bufchain_init(&ret->pending_input_data);
418 bufchain_init(&ret->pending_output_data);
419 bufchain_init(&ret->pending_oob_output_data);
421 ret->sub_socket = NULL;
422 ret->state = PROXY_STATE_NEW;
423 ret->negotiate = NULL;
425 if (cfg->proxy_type == PROXY_HTTP) {
426 ret->negotiate = proxy_http_negotiate;
427 } else if (cfg->proxy_type == PROXY_SOCKS4) {
428 ret->negotiate = proxy_socks4_negotiate;
429 } else if (cfg->proxy_type == PROXY_SOCKS5) {
430 ret->negotiate = proxy_socks5_negotiate;
431 } else if (cfg->proxy_type == PROXY_TELNET) {
432 ret->negotiate = proxy_telnet_negotiate;
434 ret->error = "Proxy error: Unknown proxy method";
438 /* create the proxy plug to map calls from the actual
439 * socket into our proxy socket layer */
440 pplug = snew(struct Plug_proxy_tag);
441 pplug->fn = &plug_fn_table;
442 pplug->proxy_socket = ret;
445 proxy_addr = sk_namelookup(cfg->proxy_host,
446 &proxy_canonical_name, cfg->addressfamily);
447 if (sk_addr_error(proxy_addr) != NULL) {
448 ret->error = "Proxy error: Unable to resolve proxy host name";
451 sfree(proxy_canonical_name);
453 /* create the actual socket we will be using,
454 * connected to our proxy server and port.
456 ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port,
458 nodelay, keepalive, (Plug) pplug);
459 if (sk_socket_error(ret->sub_socket) != NULL)
462 /* start the proxy negotiation process... */
463 sk_set_frozen(ret->sub_socket, 0);
464 ret->negotiate(ret, PROXY_CHANGE_NEW);
469 /* no proxy, so just return the direct socket */
470 return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
473 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
474 const Config *cfg, int addressfamily)
476 /* TODO: SOCKS (and potentially others) support inbound
477 * TODO: connections via the proxy. support them.
480 return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
483 /* ----------------------------------------------------------------------
484 * HTTP CONNECT proxy type.
487 static int get_line_end (char * data, int len)
493 if (data[off] == '\n') {
494 /* we have a newline */
497 /* is that the only thing on this line? */
498 if (off <= 2) return off;
500 /* if not, then there is the possibility that this header
501 * continues onto the next line, if it starts with a space
506 data[off+1] != ' ' &&
507 data[off+1] != '\t') return off;
509 /* the line does continue, so we have to keep going
510 * until we see an the header's "real" end of line.
521 int proxy_http_negotiate (Proxy_Socket p, int change)
523 if (p->state == PROXY_STATE_NEW) {
524 /* we are just beginning the proxy negotiate process,
525 * so we'll send off the initial bits of the request.
526 * for this proxy method, it's just a simple HTTP
529 char *buf, dest[512];
531 sk_getaddr(p->remote_addr, dest, lenof(dest));
533 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
534 dest, p->remote_port, dest, p->remote_port);
535 sk_write(p->sub_socket, buf, strlen(buf));
538 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
539 char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
540 char buf2[sizeof(buf)*4/3 + 100];
542 sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
544 sprintf(buf2, "Proxy-Authorization: Basic ");
545 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
546 base64_encode_atom((unsigned char *)(buf+i),
547 (len-i > 3 ? 3 : len-i), buf2+j);
548 strcpy(buf2+j, "\r\n");
549 sk_write(p->sub_socket, buf2, strlen(buf2));
552 sk_write(p->sub_socket, "\r\n", 2);
558 if (change == PROXY_CHANGE_CLOSING) {
559 /* if our proxy negotiation process involves closing and opening
560 * new sockets, then we would want to intercept this closing
561 * callback when we were expecting it. if we aren't anticipating
562 * a socket close, then some error must have occurred. we'll
563 * just pass those errors up to the backend.
565 return plug_closing(p->plug, p->closing_error_msg,
566 p->closing_error_code,
567 p->closing_calling_back);
570 if (change == PROXY_CHANGE_SENT) {
571 /* some (or all) of what we wrote to the proxy was sent.
572 * we don't do anything new, however, until we receive the
573 * proxy's response. we might want to set a timer so we can
574 * timeout the proxy negotiation after a while...
579 if (change == PROXY_CHANGE_ACCEPTING) {
580 /* we should _never_ see this, as we are using our socket to
581 * connect to a proxy, not accepting inbound connections.
582 * what should we do? close the socket with an appropriate
585 return plug_accepting(p->plug, p->accepting_sock);
588 if (change == PROXY_CHANGE_RECEIVE) {
589 /* we have received data from the underlying socket, which
590 * we'll need to parse, process, and respond to appropriately.
599 int min_ver, maj_ver, status;
601 /* get the status line */
602 len = bufchain_size(&p->pending_input_data);
603 assert(len > 0); /* or we wouldn't be here */
604 data = snewn(len+1, char);
605 bufchain_fetch(&p->pending_input_data, data, len);
607 * We must NUL-terminate this data, because Windows
608 * sscanf appears to require a NUL at the end of the
609 * string because it strlens it _first_. Sigh.
613 eol = get_line_end(data, len);
620 /* We can't rely on whether the %n incremented the sscanf return */
621 if (sscanf((char *)data, "HTTP/%i.%i %n",
622 &maj_ver, &min_ver, &status) < 2 || status == -1) {
623 plug_closing(p->plug, "Proxy error: HTTP response was absent",
624 PROXY_ERROR_GENERAL, 0);
629 /* remove the status line from the input buffer. */
630 bufchain_consume(&p->pending_input_data, eol);
631 if (data[status] != '2') {
635 while (eol > status &&
636 (data[eol-1] == '\r' || data[eol-1] == '\n'))
638 buf = dupprintf("Proxy error: %s", data+status);
639 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
652 /* get headers. we're done when we get a
653 * header of length 2, (ie. just "\r\n")
656 len = bufchain_size(&p->pending_input_data);
657 assert(len > 0); /* or we wouldn't be here */
658 data = snewn(len, char);
660 bufchain_fetch(&p->pending_input_data, data, len);
662 eol = get_line_end(datap, len);
669 bufchain_consume(&p->pending_input_data, eol);
672 eol = get_line_end(datap, len);
677 bufchain_consume(&p->pending_input_data, 2);
679 /* proxy activate will have dealt with
680 * whatever is left of the buffer */
690 plug_closing(p->plug, "Proxy error: unexpected proxy error",
691 PROXY_ERROR_UNEXPECTED, 0);
695 /* ----------------------------------------------------------------------
699 /* SOCKS version 4 */
700 int proxy_socks4_negotiate (Proxy_Socket p, int change)
702 if (p->state == PROXY_CHANGE_NEW) {
705 * version number (1 byte) = 4
706 * command code (1 byte)
709 * dest. port (2 bytes) [network order]
710 * dest. address (4 bytes)
711 * user ID (variable length, null terminated string)
714 int length, type, namelen;
715 char *command, addr[4], hostname[512];
717 type = sk_addrtype(p->remote_addr);
718 if (type == ADDRTYPE_IPV6) {
719 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
720 " not support IPv6", PROXY_ERROR_GENERAL, 0);
722 } else if (type == ADDRTYPE_IPV4) {
724 sk_addrcopy(p->remote_addr, addr);
725 } else { /* type == ADDRTYPE_NAME */
726 assert(type == ADDRTYPE_NAME);
727 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
728 namelen = strlen(hostname) + 1; /* include the NUL */
729 addr[0] = addr[1] = addr[2] = 0;
733 length = strlen(p->cfg.proxy_username) + namelen + 9;
734 command = snewn(length, char);
735 strcpy(command + 8, p->cfg.proxy_username);
737 command[0] = 4; /* version 4 */
738 command[1] = 1; /* CONNECT command */
741 command[2] = (char) (p->remote_port >> 8) & 0xff;
742 command[3] = (char) p->remote_port & 0xff;
745 memcpy(command + 4, addr, 4);
748 memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1,
751 sk_write(p->sub_socket, command, length);
758 if (change == PROXY_CHANGE_CLOSING) {
759 /* if our proxy negotiation process involves closing and opening
760 * new sockets, then we would want to intercept this closing
761 * callback when we were expecting it. if we aren't anticipating
762 * a socket close, then some error must have occurred. we'll
763 * just pass those errors up to the backend.
765 return plug_closing(p->plug, p->closing_error_msg,
766 p->closing_error_code,
767 p->closing_calling_back);
770 if (change == PROXY_CHANGE_SENT) {
771 /* some (or all) of what we wrote to the proxy was sent.
772 * we don't do anything new, however, until we receive the
773 * proxy's response. we might want to set a timer so we can
774 * timeout the proxy negotiation after a while...
779 if (change == PROXY_CHANGE_ACCEPTING) {
780 /* we should _never_ see this, as we are using our socket to
781 * connect to a proxy, not accepting inbound connections.
782 * what should we do? close the socket with an appropriate
785 return plug_accepting(p->plug, p->accepting_sock);
788 if (change == PROXY_CHANGE_RECEIVE) {
789 /* we have received data from the underlying socket, which
790 * we'll need to parse, process, and respond to appropriately.
795 * version number (1 byte) = 4
796 * reply code (1 byte)
797 * 90 = request granted
798 * 91 = request rejected or failed
799 * 92 = request rejected due to lack of IDENTD on client
800 * 93 = request rejected due to difference in user ID
801 * (what we sent vs. what IDENTD said)
802 * dest. port (2 bytes)
803 * dest. address (4 bytes)
808 if (bufchain_size(&p->pending_input_data) < 8)
809 return 1; /* not got anything yet */
811 /* get the response */
812 bufchain_fetch(&p->pending_input_data, data, 8);
815 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
816 "unexpected reply code version",
817 PROXY_ERROR_GENERAL, 0);
825 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
826 PROXY_ERROR_GENERAL, 0);
829 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
830 PROXY_ERROR_GENERAL, 0);
834 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
835 PROXY_ERROR_GENERAL, 0);
841 bufchain_consume(&p->pending_input_data, 8);
845 /* proxy activate will have dealt with
846 * whatever is left of the buffer */
851 plug_closing(p->plug, "Proxy error: unexpected proxy error",
852 PROXY_ERROR_UNEXPECTED, 0);
856 /* SOCKS version 5 */
857 int proxy_socks5_negotiate (Proxy_Socket p, int change)
859 if (p->state == PROXY_CHANGE_NEW) {
862 * version number (1 byte) = 5
863 * number of available authentication methods (1 byte)
864 * available authentication methods (1 byte * previous value)
865 * authentication methods:
866 * 0x00 = no authentication
868 * 0x02 = username/password
875 command[0] = 5; /* version 5 */
876 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
877 command[2] = 0x00; /* no authentication */
879 proxy_socks5_offerencryptedauth (command, &len);
880 command[len++] = 0x02; /* username/password */
881 command[1] = len - 2; /* Number of methods supported */
883 command[1] = 1; /* one methods supported: */
884 command[2] = 0x00; /* no authentication */
888 sk_write(p->sub_socket, command, len);
894 if (change == PROXY_CHANGE_CLOSING) {
895 /* if our proxy negotiation process involves closing and opening
896 * new sockets, then we would want to intercept this closing
897 * callback when we were expecting it. if we aren't anticipating
898 * a socket close, then some error must have occurred. we'll
899 * just pass those errors up to the backend.
901 return plug_closing(p->plug, p->closing_error_msg,
902 p->closing_error_code,
903 p->closing_calling_back);
906 if (change == PROXY_CHANGE_SENT) {
907 /* some (or all) of what we wrote to the proxy was sent.
908 * we don't do anything new, however, until we receive the
909 * proxy's response. we might want to set a timer so we can
910 * timeout the proxy negotiation after a while...
915 if (change == PROXY_CHANGE_ACCEPTING) {
916 /* we should _never_ see this, as we are using our socket to
917 * connect to a proxy, not accepting inbound connections.
918 * what should we do? close the socket with an appropriate
921 return plug_accepting(p->plug, p->accepting_sock);
924 if (change == PROXY_CHANGE_RECEIVE) {
925 /* we have received data from the underlying socket, which
926 * we'll need to parse, process, and respond to appropriately.
932 * version number (1 byte) = 5
933 * authentication method (1 byte)
934 * authentication methods:
935 * 0x00 = no authentication
937 * 0x02 = username/password
939 * 0xff = no acceptable methods
943 if (bufchain_size(&p->pending_input_data) < 2)
944 return 1; /* not got anything yet */
946 /* get the response */
947 bufchain_fetch(&p->pending_input_data, data, 2);
950 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
951 PROXY_ERROR_GENERAL, 0);
955 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
956 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
957 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
958 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
960 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
961 PROXY_ERROR_GENERAL, 0);
964 bufchain_consume(&p->pending_input_data, 2);
969 /* password authentication reply format:
970 * version number (1 bytes) = 1
971 * reply code (1 byte)
977 if (bufchain_size(&p->pending_input_data) < 2)
978 return 1; /* not got anything yet */
980 /* get the response */
981 bufchain_fetch(&p->pending_input_data, data, 2);
984 plug_closing(p->plug, "Proxy error: SOCKS password "
985 "subnegotiation contained wrong version number",
986 PROXY_ERROR_GENERAL, 0);
992 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
993 " password authentication",
994 PROXY_ERROR_GENERAL, 0);
998 bufchain_consume(&p->pending_input_data, 2);
999 p->state = 2; /* now proceed as authenticated */
1002 if (p->state == 8) {
1004 ret = proxy_socks5_handlechap(p);
1005 if (ret) return ret;
1008 if (p->state == 2) {
1011 * version number (1 byte) = 5
1012 * command code (1 byte)
1016 * reserved (1 byte) = 0x00
1017 * address type (1 byte)
1019 * 3 = domainname (first byte has length, no terminating null)
1021 * dest. address (variable)
1022 * dest. port (2 bytes) [network order]
1029 type = sk_addrtype(p->remote_addr);
1030 if (type == ADDRTYPE_IPV4) {
1031 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1032 command[3] = 1; /* IPv4 */
1033 sk_addrcopy(p->remote_addr, command+4);
1034 } else if (type == ADDRTYPE_IPV6) {
1035 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1036 command[3] = 4; /* IPv6 */
1037 sk_addrcopy(p->remote_addr, command+4);
1039 assert(type == ADDRTYPE_NAME);
1041 sk_getaddr(p->remote_addr, command+5, 256);
1042 command[4] = strlen(command+5);
1043 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1046 command[0] = 5; /* version 5 */
1047 command[1] = 1; /* CONNECT command */
1051 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1052 command[len-1] = (char) p->remote_port & 0xff;
1054 sk_write(p->sub_socket, command, len);
1060 if (p->state == 3) {
1063 * version number (1 bytes) = 5
1064 * reply code (1 byte)
1066 * 1 = general SOCKS server failure
1067 * 2 = connection not allowed by ruleset
1068 * 3 = network unreachable
1069 * 4 = host unreachable
1070 * 5 = connection refused
1072 * 7 = command not supported
1073 * 8 = address type not supported
1074 * reserved (1 byte) = x00
1075 * address type (1 byte)
1077 * 3 = domainname (first byte has length, no terminating null)
1079 * server bound address (variable)
1080 * server bound port (2 bytes) [network order]
1085 /* First 5 bytes of packet are enough to tell its length. */
1086 if (bufchain_size(&p->pending_input_data) < 5)
1087 return 1; /* not got anything yet */
1089 /* get the response */
1090 bufchain_fetch(&p->pending_input_data, data, 5);
1093 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1094 PROXY_ERROR_GENERAL, 0);
1101 strcpy(buf, "Proxy error: ");
1104 case 1: strcat(buf, "General SOCKS server failure"); break;
1105 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1106 case 3: strcat(buf, "Network unreachable"); break;
1107 case 4: strcat(buf, "Host unreachable"); break;
1108 case 5: strcat(buf, "Connection refused"); break;
1109 case 6: strcat(buf, "TTL expired"); break;
1110 case 7: strcat(buf, "Command not supported"); break;
1111 case 8: strcat(buf, "Address type not supported"); break;
1112 default: sprintf(buf+strlen(buf),
1113 "Unrecognised SOCKS error code %d",
1117 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1123 * Eat the rest of the reply packet.
1125 len = 6; /* first 4 bytes, last 2 */
1127 case 1: len += 4; break; /* IPv4 address */
1128 case 4: len += 16; break;/* IPv6 address */
1129 case 3: len += (unsigned char)data[4]; break; /* domain name */
1131 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1132 "unrecognised address format",
1133 PROXY_ERROR_GENERAL, 0);
1136 if (bufchain_size(&p->pending_input_data) < len)
1137 return 1; /* not got whole reply yet */
1138 bufchain_consume(&p->pending_input_data, len);
1145 if (p->state == 4) {
1146 /* TODO: Handle GSSAPI authentication */
1147 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1148 PROXY_ERROR_GENERAL, 0);
1152 if (p->state == 5) {
1153 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
1154 char userpwbuf[514];
1156 ulen = strlen(p->cfg.proxy_username);
1157 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1158 plen = strlen(p->cfg.proxy_password);
1159 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1160 userpwbuf[0] = 1; /* version number of subnegotiation */
1161 userpwbuf[1] = ulen;
1162 memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
1163 userpwbuf[ulen+2] = plen;
1164 memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen);
1165 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1168 plug_closing(p->plug, "Proxy error: Server chose "
1169 "username/password authentication but we "
1171 PROXY_ERROR_GENERAL, 0);
1175 if (p->state == 6) {
1177 ret = proxy_socks5_selectchap(p);
1178 if (ret) return ret;
1183 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1184 PROXY_ERROR_UNEXPECTED, 0);
1188 /* ----------------------------------------------------------------------
1189 * `Telnet' proxy type.
1191 * (This is for ad-hoc proxies where you connect to the proxy's
1192 * telnet port and send a command such as `connect host port'. The
1193 * command is configurable, since this proxy type is typically not
1194 * standardised or at all well-defined.)
1197 char *format_telnet_command(SockAddr addr, int port, const Config *cfg)
1200 int retlen = 0, retsize = 0;
1202 #define ENSURE(n) do { \
1203 if (retsize < retlen + n) { \
1204 retsize = retlen + n + 512; \
1205 ret = sresize(ret, retsize, char); \
1209 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1210 * %%, %host, %port, %user, and %pass
1213 while (cfg->proxy_telnet_command[eo] != 0) {
1215 /* scan forward until we hit end-of-line,
1216 * or an escape character (\ or %) */
1217 while (cfg->proxy_telnet_command[eo] != 0 &&
1218 cfg->proxy_telnet_command[eo] != '%' &&
1219 cfg->proxy_telnet_command[eo] != '\\') eo++;
1221 /* if we hit eol, break out of our escaping loop */
1222 if (cfg->proxy_telnet_command[eo] == 0) break;
1224 /* if there was any unescaped text before the escape
1225 * character, send that now */
1228 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1234 /* if the escape character was the last character of
1235 * the line, we'll just stop and send it. */
1236 if (cfg->proxy_telnet_command[eo] == 0) break;
1238 if (cfg->proxy_telnet_command[so] == '\\') {
1240 /* we recognize \\, \%, \r, \n, \t, \x??.
1241 * anything else, we just send unescaped (including the \).
1244 switch (cfg->proxy_telnet_command[eo]) {
1248 ret[retlen++] = '\\';
1254 ret[retlen++] = '%';
1260 ret[retlen++] = '\r';
1266 ret[retlen++] = '\n';
1272 ret[retlen++] = '\t';
1279 /* escaped hexadecimal value (ie. \xff) */
1280 unsigned char v = 0;
1285 if (cfg->proxy_telnet_command[eo] >= '0' &&
1286 cfg->proxy_telnet_command[eo] <= '9')
1287 v += cfg->proxy_telnet_command[eo] - '0';
1288 else if (cfg->proxy_telnet_command[eo] >= 'a' &&
1289 cfg->proxy_telnet_command[eo] <= 'f')
1290 v += cfg->proxy_telnet_command[eo] - 'a' + 10;
1291 else if (cfg->proxy_telnet_command[eo] >= 'A' &&
1292 cfg->proxy_telnet_command[eo] <= 'F')
1293 v += cfg->proxy_telnet_command[eo] - 'A' + 10;
1295 /* non hex character, so we abort and just
1296 * send the whole thing unescaped (including \x)
1299 ret[retlen++] = '\\';
1304 /* we only extract two hex characters */
1320 memcpy(ret+retlen, cfg->proxy_telnet_command + so, 2);
1327 /* % escape. we recognize %%, %host, %port, %user, %pass.
1328 * %proxyhost, %proxyport. Anything else we just send
1329 * unescaped (including the %).
1332 if (cfg->proxy_telnet_command[eo] == '%') {
1334 ret[retlen++] = '%';
1337 else if (strnicmp(cfg->proxy_telnet_command + eo,
1341 sk_getaddr(addr, dest, lenof(dest));
1342 destlen = strlen(dest);
1344 memcpy(ret+retlen, dest, destlen);
1348 else if (strnicmp(cfg->proxy_telnet_command + eo,
1350 char portstr[8], portlen;
1351 portlen = sprintf(portstr, "%i", port);
1353 memcpy(ret + retlen, portstr, portlen);
1357 else if (strnicmp(cfg->proxy_telnet_command + eo,
1359 int userlen = strlen(cfg->proxy_username);
1361 memcpy(ret+retlen, cfg->proxy_username, userlen);
1365 else if (strnicmp(cfg->proxy_telnet_command + eo,
1367 int passlen = strlen(cfg->proxy_password);
1369 memcpy(ret+retlen, cfg->proxy_password, passlen);
1373 else if (strnicmp(cfg->proxy_telnet_command + eo,
1374 "proxyhost", 4) == 0) {
1375 int phlen = strlen(cfg->proxy_host);
1377 memcpy(ret+retlen, cfg->proxy_host, phlen);
1381 else if (strnicmp(cfg->proxy_telnet_command + eo,
1382 "proxyport", 4) == 0) {
1385 sprintf(pport, "%d", cfg->proxy_port);
1386 pplen = strlen(cfg->proxy_host);
1388 memcpy(ret+retlen, pport, pplen);
1393 /* we don't escape this, so send the % now, and
1394 * don't advance eo, so that we'll consider the
1395 * text immediately following the % as unescaped.
1398 ret[retlen++] = '%';
1402 /* resume scanning for additional escapes after this one. */
1406 /* if there is any unescaped text at the end of the line, send it */
1409 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1420 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1422 if (p->state == PROXY_CHANGE_NEW) {
1423 char *formatted_cmd;
1425 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1428 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1429 sfree(formatted_cmd);
1435 if (change == PROXY_CHANGE_CLOSING) {
1436 /* if our proxy negotiation process involves closing and opening
1437 * new sockets, then we would want to intercept this closing
1438 * callback when we were expecting it. if we aren't anticipating
1439 * a socket close, then some error must have occurred. we'll
1440 * just pass those errors up to the backend.
1442 return plug_closing(p->plug, p->closing_error_msg,
1443 p->closing_error_code,
1444 p->closing_calling_back);
1447 if (change == PROXY_CHANGE_SENT) {
1448 /* some (or all) of what we wrote to the proxy was sent.
1449 * we don't do anything new, however, until we receive the
1450 * proxy's response. we might want to set a timer so we can
1451 * timeout the proxy negotiation after a while...
1456 if (change == PROXY_CHANGE_ACCEPTING) {
1457 /* we should _never_ see this, as we are using our socket to
1458 * connect to a proxy, not accepting inbound connections.
1459 * what should we do? close the socket with an appropriate
1462 return plug_accepting(p->plug, p->accepting_sock);
1465 if (change == PROXY_CHANGE_RECEIVE) {
1466 /* we have received data from the underlying socket, which
1467 * we'll need to parse, process, and respond to appropriately.
1472 /* proxy activate will have dealt with
1473 * whatever is left of the buffer */
1477 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1478 PROXY_ERROR_UNEXPECTED, 0);