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 \
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, 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, 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)
255 int hostip_len, hostname_len;
259 * Check the host name and IP against the hard-coded
260 * representations of `localhost'.
262 if (!cfg.even_proxy_localhost &&
263 (sk_hostname_is_local(hostname) ||
264 (addr && sk_address_is_local(addr))))
265 return 0; /* do not proxy */
267 /* we want a string representation of the IP address for comparisons */
269 sk_getaddr(addr, hostip, 64);
270 hostip_len = strlen(hostip);
273 hostname_len = strlen(hostname);
275 exclude_list = cfg.proxy_exclude_list;
277 /* now parse the exclude list, and see if either our IP
278 * or hostname matches anything in it.
281 while (exclude_list[s]) {
282 while (exclude_list[s] &&
283 (isspace(exclude_list[s]) ||
284 exclude_list[s] == ',')) s++;
286 if (!exclude_list[s]) break;
290 while (exclude_list[e] &&
291 (isalnum(exclude_list[e]) ||
292 exclude_list[e] == '-' ||
293 exclude_list[e] == '.' ||
294 exclude_list[e] == '*')) e++;
296 if (exclude_list[s] == '*') {
297 /* wildcard at beginning of entry */
299 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
300 exclude_list + s + 1, e - s - 1) == 0) ||
301 strnicmp(hostname + hostname_len - (e - s - 1),
302 exclude_list + s + 1, e - s - 1) == 0)
303 return 0; /* IP/hostname range excluded. do not use proxy. */
305 } else if (exclude_list[e-1] == '*') {
306 /* wildcard at end of entry */
308 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
309 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
310 return 0; /* IP/hostname range excluded. do not use proxy. */
313 /* no wildcard at either end, so let's try an absolute
314 * match (ie. a specific IP)
317 if (addr && stricmp(hostip, exclude_list + s) == 0)
318 return 0; /* IP/hostname excluded. do not use proxy. */
319 if (stricmp(hostname, exclude_list + s) == 0)
320 return 0; /* IP/hostname excluded. do not use proxy. */
326 /* no matches in the exclude list, so use the proxy */
330 SockAddr name_lookup(char *host, int port, char **canonicalname)
332 if (cfg.proxy_type != PROXY_NONE &&
333 do_proxy_dns && proxy_for_destination(NULL, host, port)) {
334 *canonicalname = dupstr(host);
335 return sk_nonamelookup(host);
338 return sk_namelookup(host, canonicalname);
341 Socket new_connection(SockAddr addr, char *hostname,
342 int port, int privport,
343 int oobinline, int nodelay, Plug plug)
345 static const struct socket_function_table socket_fn_table = {
351 sk_proxy_set_private_ptr,
352 sk_proxy_get_private_ptr,
354 sk_proxy_socket_error
357 static const struct plug_function_table plug_fn_table = {
364 if (cfg.proxy_type != PROXY_NONE &&
365 proxy_for_destination(addr, hostname, port))
370 char *proxy_canonical_name, *err;
372 ret = smalloc(sizeof(struct Socket_proxy_tag));
373 ret->fn = &socket_fn_table;
375 ret->remote_addr = addr;
376 ret->remote_port = port;
379 ret->pending_flush = 0;
382 bufchain_init(&ret->pending_input_data);
383 bufchain_init(&ret->pending_output_data);
384 bufchain_init(&ret->pending_oob_output_data);
386 ret->sub_socket = NULL;
387 ret->state = PROXY_STATE_NEW;
388 ret->negotiate = NULL;
390 if (cfg.proxy_type == PROXY_HTTP) {
391 ret->negotiate = proxy_http_negotiate;
392 } else if (cfg.proxy_type == PROXY_SOCKS) {
393 if (cfg.proxy_socks_version == 4)
394 ret->negotiate = proxy_socks4_negotiate;
396 ret->negotiate = proxy_socks5_negotiate;
397 } else if (cfg.proxy_type == PROXY_TELNET) {
398 ret->negotiate = proxy_telnet_negotiate;
400 ret->error = "Proxy error: Unknown proxy method";
404 /* create the proxy plug to map calls from the actual
405 * socket into our proxy socket layer */
406 pplug = smalloc(sizeof(struct Plug_proxy_tag));
407 pplug->fn = &plug_fn_table;
408 pplug->proxy_socket = ret;
411 proxy_addr = sk_namelookup(cfg.proxy_host,
412 &proxy_canonical_name);
413 if ((err = sk_addr_error(proxy_addr))) {
414 ret->error = "Proxy error: Unable to resolve proxy host name";
417 sfree(proxy_canonical_name);
419 /* create the actual socket we will be using,
420 * connected to our proxy server and port.
422 ret->sub_socket = sk_new(proxy_addr, cfg.proxy_port,
424 nodelay, (Plug) pplug);
425 if (sk_socket_error(ret->sub_socket) != NULL)
428 sk_addr_free(proxy_addr);
430 /* start the proxy negotiation process... */
431 sk_set_frozen(ret->sub_socket, 0);
432 ret->negotiate(ret, PROXY_CHANGE_NEW);
437 /* no proxy, so just return the direct socket */
438 return sk_new(addr, port, privport, oobinline, nodelay, plug);
441 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only)
443 /* TODO: SOCKS (and potentially others) support inbound
444 * TODO: connections via the proxy. support them.
447 return sk_newlistener(srcaddr, port, plug, local_host_only);
450 /* ----------------------------------------------------------------------
451 * HTTP CONNECT proxy type.
454 static int get_line_end (char * data, int len)
460 if (data[off] == '\n') {
461 /* we have a newline */
464 /* is that the only thing on this line? */
465 if (off <= 2) return off;
467 /* if not, then there is the possibility that this header
468 * continues onto the next line, if it starts with a space
473 data[off+1] != ' ' &&
474 data[off+1] != '\t') return off;
476 /* the line does continue, so we have to keep going
477 * until we see an the header's "real" end of line.
488 int proxy_http_negotiate (Proxy_Socket p, int change)
490 if (p->state == PROXY_STATE_NEW) {
491 /* we are just beginning the proxy negotiate process,
492 * so we'll send off the initial bits of the request.
493 * for this proxy method, it's just a simple HTTP
496 char *buf, dest[512];
498 sk_getaddr(p->remote_addr, dest, lenof(dest));
500 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
501 dest, p->remote_port, dest, p->remote_port);
502 sk_write(p->sub_socket, buf, strlen(buf));
505 if (cfg.proxy_username[0] || cfg.proxy_password[0]) {
506 char buf[sizeof(cfg.proxy_username)+sizeof(cfg.proxy_password)];
507 char buf2[sizeof(buf)*4/3 + 100];
509 sprintf(buf, "%s:%s", cfg.proxy_username, cfg.proxy_password);
511 sprintf(buf2, "Proxy-Authorization: basic ");
512 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
513 base64_encode_atom(buf+i, (len-i > 3 ? 3 : len-i), buf2+j);
514 strcpy(buf2+j, "\r\n");
515 sk_write(p->sub_socket, buf2, strlen(buf2));
518 sk_write(p->sub_socket, "\r\n", 2);
524 if (change == PROXY_CHANGE_CLOSING) {
525 /* if our proxy negotiation process involves closing and opening
526 * new sockets, then we would want to intercept this closing
527 * callback when we were expecting it. if we aren't anticipating
528 * a socket close, then some error must have occurred. we'll
529 * just pass those errors up to the backend.
531 return plug_closing(p->plug, p->closing_error_msg,
532 p->closing_error_code,
533 p->closing_calling_back);
536 if (change == PROXY_CHANGE_SENT) {
537 /* some (or all) of what we wrote to the proxy was sent.
538 * we don't do anything new, however, until we receive the
539 * proxy's response. we might want to set a timer so we can
540 * timeout the proxy negotiation after a while...
545 if (change == PROXY_CHANGE_ACCEPTING) {
546 /* we should _never_ see this, as we are using our socket to
547 * connect to a proxy, not accepting inbound connections.
548 * what should we do? close the socket with an appropriate
551 return plug_accepting(p->plug, p->accepting_sock);
554 if (change == PROXY_CHANGE_RECEIVE) {
555 /* we have received data from the underlying socket, which
556 * we'll need to parse, process, and respond to appropriately.
565 int min_ver, maj_ver, status;
567 /* get the status line */
568 len = bufchain_size(&p->pending_input_data);
569 assert(len > 0); /* or we wouldn't be here */
571 bufchain_fetch(&p->pending_input_data, data, len);
573 eol = get_line_end(data, len);
580 /* We can't rely on whether the %n incremented the sscanf return */
581 if (sscanf((char *)data, "HTTP/%i.%i %n",
582 &maj_ver, &min_ver, &status) < 2 || status == -1) {
583 plug_closing(p->plug, "Proxy error: HTTP response was absent",
584 PROXY_ERROR_GENERAL, 0);
589 /* remove the status line from the input buffer. */
590 bufchain_consume(&p->pending_input_data, eol);
591 if (data[status] != '2') {
595 while (eol > status &&
596 (data[eol-1] == '\r' || data[eol-1] == '\n'))
598 buf = dupprintf("Proxy error: %s", data+status);
599 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
612 /* get headers. we're done when we get a
613 * header of length 2, (ie. just "\r\n")
616 len = bufchain_size(&p->pending_input_data);
617 assert(len > 0); /* or we wouldn't be here */
620 bufchain_fetch(&p->pending_input_data, data, len);
622 eol = get_line_end(datap, len);
629 bufchain_consume(&p->pending_input_data, eol);
632 eol = get_line_end(datap, len);
637 bufchain_consume(&p->pending_input_data, 2);
639 /* proxy activate will have dealt with
640 * whatever is left of the buffer */
650 plug_closing(p->plug, "Proxy error: unexpected proxy error",
651 PROXY_ERROR_UNEXPECTED, 0);
655 /* ----------------------------------------------------------------------
659 /* SOCKS version 4 */
660 int proxy_socks4_negotiate (Proxy_Socket p, int change)
662 if (p->state == PROXY_CHANGE_NEW) {
665 * version number (1 byte) = 4
666 * command code (1 byte)
669 * dest. port (2 bytes) [network order]
670 * dest. address (4 bytes)
671 * user ID (variable length, null terminated string)
674 int length, type, namelen;
675 char *command, addr[4], hostname[512];
677 type = sk_addrtype(p->remote_addr);
678 if (type == ADDRTYPE_IPV6) {
679 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
680 " not support IPv6", PROXY_ERROR_GENERAL, 0);
682 } else if (type == ADDRTYPE_IPV4) {
684 sk_addrcopy(p->remote_addr, addr);
685 } else { /* type == ADDRTYPE_NAME */
686 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
687 namelen = strlen(hostname) + 1; /* include the NUL */
688 addr[0] = addr[1] = addr[2] = 0;
692 length = strlen(cfg.proxy_username) + namelen + 9;
693 command = (char*) smalloc(length);
694 strcpy(command + 8, cfg.proxy_username);
696 command[0] = 4; /* version 4 */
697 command[1] = 1; /* CONNECT command */
700 command[2] = (char) (p->remote_port >> 8) & 0xff;
701 command[3] = (char) p->remote_port & 0xff;
704 memcpy(command + 4, addr, 4);
707 memcpy(command + 8 + strlen(cfg.proxy_username) + 1,
710 sk_write(p->sub_socket, command, length);
717 if (change == PROXY_CHANGE_CLOSING) {
718 /* if our proxy negotiation process involves closing and opening
719 * new sockets, then we would want to intercept this closing
720 * callback when we were expecting it. if we aren't anticipating
721 * a socket close, then some error must have occurred. we'll
722 * just pass those errors up to the backend.
724 return plug_closing(p->plug, p->closing_error_msg,
725 p->closing_error_code,
726 p->closing_calling_back);
729 if (change == PROXY_CHANGE_SENT) {
730 /* some (or all) of what we wrote to the proxy was sent.
731 * we don't do anything new, however, until we receive the
732 * proxy's response. we might want to set a timer so we can
733 * timeout the proxy negotiation after a while...
738 if (change == PROXY_CHANGE_ACCEPTING) {
739 /* we should _never_ see this, as we are using our socket to
740 * connect to a proxy, not accepting inbound connections.
741 * what should we do? close the socket with an appropriate
744 return plug_accepting(p->plug, p->accepting_sock);
747 if (change == PROXY_CHANGE_RECEIVE) {
748 /* we have received data from the underlying socket, which
749 * we'll need to parse, process, and respond to appropriately.
754 * version number (1 byte) = 4
755 * reply code (1 byte)
756 * 90 = request granted
757 * 91 = request rejected or failed
758 * 92 = request rejected due to lack of IDENTD on client
759 * 93 = request rejected due to difference in user ID
760 * (what we sent vs. what IDENTD said)
761 * dest. port (2 bytes)
762 * dest. address (4 bytes)
767 if (bufchain_size(&p->pending_input_data) < 8)
768 return 1; /* not got anything yet */
770 /* get the response */
771 bufchain_fetch(&p->pending_input_data, data, 8);
774 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
775 "unexpected reply code version",
776 PROXY_ERROR_GENERAL, 0);
784 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
785 PROXY_ERROR_GENERAL, 0);
788 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
789 PROXY_ERROR_GENERAL, 0);
793 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
794 PROXY_ERROR_GENERAL, 0);
800 bufchain_consume(&p->pending_input_data, 8);
804 /* proxy activate will have dealt with
805 * whatever is left of the buffer */
810 plug_closing(p->plug, "Proxy error: unexpected proxy error",
811 PROXY_ERROR_UNEXPECTED, 0);
815 /* SOCKS version 5 */
816 int proxy_socks5_negotiate (Proxy_Socket p, int change)
818 if (p->state == PROXY_CHANGE_NEW) {
821 * version number (1 byte) = 5
822 * number of available authentication methods (1 byte)
823 * available authentication methods (1 byte * previous value)
824 * authentication methods:
825 * 0x00 = no authentication
827 * 0x02 = username/password
834 command[0] = 5; /* version 5 */
835 if (cfg.proxy_username[0] || cfg.proxy_password[0]) {
836 command[1] = 2; /* two methods supported: */
837 command[2] = 0x00; /* no authentication */
838 command[3] = 0x02; /* username/password */
841 command[1] = 1; /* one methods supported: */
842 command[2] = 0x00; /* no authentication */
846 sk_write(p->sub_socket, command, len);
852 if (change == PROXY_CHANGE_CLOSING) {
853 /* if our proxy negotiation process involves closing and opening
854 * new sockets, then we would want to intercept this closing
855 * callback when we were expecting it. if we aren't anticipating
856 * a socket close, then some error must have occurred. we'll
857 * just pass those errors up to the backend.
859 return plug_closing(p->plug, p->closing_error_msg,
860 p->closing_error_code,
861 p->closing_calling_back);
864 if (change == PROXY_CHANGE_SENT) {
865 /* some (or all) of what we wrote to the proxy was sent.
866 * we don't do anything new, however, until we receive the
867 * proxy's response. we might want to set a timer so we can
868 * timeout the proxy negotiation after a while...
873 if (change == PROXY_CHANGE_ACCEPTING) {
874 /* we should _never_ see this, as we are using our socket to
875 * connect to a proxy, not accepting inbound connections.
876 * what should we do? close the socket with an appropriate
879 return plug_accepting(p->plug, p->accepting_sock);
882 if (change == PROXY_CHANGE_RECEIVE) {
883 /* we have received data from the underlying socket, which
884 * we'll need to parse, process, and respond to appropriately.
890 * version number (1 byte) = 5
891 * authentication method (1 byte)
892 * authentication methods:
893 * 0x00 = no authentication
895 * 0x02 = username/password
897 * 0xff = no acceptable methods
901 if (bufchain_size(&p->pending_input_data) < 2)
902 return 1; /* not got anything yet */
904 /* get the response */
905 bufchain_fetch(&p->pending_input_data, data, 2);
908 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
909 PROXY_ERROR_GENERAL, 0);
913 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
914 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
915 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
916 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
918 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
919 PROXY_ERROR_GENERAL, 0);
922 bufchain_consume(&p->pending_input_data, 2);
927 /* password authentication reply format:
928 * version number (1 bytes) = 1
929 * reply code (1 byte)
935 if (bufchain_size(&p->pending_input_data) < 2)
936 return 1; /* not got anything yet */
938 /* get the response */
939 bufchain_fetch(&p->pending_input_data, data, 2);
942 plug_closing(p->plug, "Proxy error: SOCKS password "
943 "subnegotiation contained wrong version number",
944 PROXY_ERROR_GENERAL, 0);
950 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
951 " password authentication",
952 PROXY_ERROR_GENERAL, 0);
956 bufchain_consume(&p->pending_input_data, 2);
957 p->state = 2; /* now proceed as authenticated */
963 * version number (1 byte) = 5
964 * command code (1 byte)
968 * reserved (1 byte) = 0x00
969 * address type (1 byte)
971 * 3 = domainname (first byte has length, no terminating null)
973 * dest. address (variable)
974 * dest. port (2 bytes) [network order]
981 type = sk_addrtype(p->remote_addr);
982 if (type == ADDRTYPE_IPV4) {
983 len = 10; /* 4 hdr + 4 addr + 2 trailer */
984 command[3] = 1; /* IPv4 */
985 sk_addrcopy(p->remote_addr, command+4);
986 } else if (type == ADDRTYPE_IPV6) {
987 len = 22; /* 4 hdr + 16 addr + 2 trailer */
988 command[3] = 4; /* IPv6 */
989 sk_addrcopy(p->remote_addr, command+4);
990 } else if (type == ADDRTYPE_NAME) {
992 sk_getaddr(p->remote_addr, command+5, 256);
993 command[4] = strlen(command+5);
994 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
997 command[0] = 5; /* version 5 */
998 command[1] = 1; /* CONNECT command */
1002 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1003 command[len-1] = (char) p->remote_port & 0xff;
1005 sk_write(p->sub_socket, command, len);
1011 if (p->state == 3) {
1014 * version number (1 bytes) = 5
1015 * reply code (1 byte)
1017 * 1 = general SOCKS server failure
1018 * 2 = connection not allowed by ruleset
1019 * 3 = network unreachable
1020 * 4 = host unreachable
1021 * 5 = connection refused
1023 * 7 = command not supported
1024 * 8 = address type not supported
1025 * reserved (1 byte) = x00
1026 * address type (1 byte)
1028 * 3 = domainname (first byte has length, no terminating null)
1030 * server bound address (variable)
1031 * server bound port (2 bytes) [network order]
1036 /* First 5 bytes of packet are enough to tell its length. */
1037 if (bufchain_size(&p->pending_input_data) < 5)
1038 return 1; /* not got anything yet */
1040 /* get the response */
1041 bufchain_fetch(&p->pending_input_data, data, 5);
1044 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1045 PROXY_ERROR_GENERAL, 0);
1052 strcpy(buf, "Proxy error: ");
1055 case 1: strcat(buf, "General SOCKS server failure"); break;
1056 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1057 case 3: strcat(buf, "Network unreachable"); break;
1058 case 4: strcat(buf, "Host unreachable"); break;
1059 case 5: strcat(buf, "Connection refused"); break;
1060 case 6: strcat(buf, "TTL expired"); break;
1061 case 7: strcat(buf, "Command not supported"); break;
1062 case 8: strcat(buf, "Address type not supported"); break;
1063 default: sprintf(buf+strlen(buf),
1064 "Unrecognised SOCKS error code %d",
1068 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1074 * Eat the rest of the reply packet.
1076 len = 6; /* first 4 bytes, last 2 */
1078 case 1: len += 4; break; /* IPv4 address */
1079 case 4: len += 16; break;/* IPv6 address */
1080 case 3: len += (unsigned char)data[4]; break; /* domain name */
1082 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1083 "unrecognised address format",
1084 PROXY_ERROR_GENERAL, 0);
1087 if (bufchain_size(&p->pending_input_data) < len)
1088 return 1; /* not got whole reply yet */
1089 bufchain_consume(&p->pending_input_data, len);
1096 if (p->state == 4) {
1097 /* TODO: Handle GSSAPI authentication */
1098 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1099 PROXY_ERROR_GENERAL, 0);
1103 if (p->state == 5) {
1104 if (cfg.proxy_username[0] || cfg.proxy_password[0]) {
1105 char userpwbuf[514];
1107 ulen = strlen(cfg.proxy_username);
1108 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1109 plen = strlen(cfg.proxy_password);
1110 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1111 userpwbuf[0] = 1; /* version number of subnegotiation */
1112 userpwbuf[1] = ulen;
1113 memcpy(userpwbuf+2, cfg.proxy_username, ulen);
1114 userpwbuf[ulen+2] = plen;
1115 memcpy(userpwbuf+ulen+3, cfg.proxy_password, plen);
1116 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1119 plug_closing(p->plug, "Proxy error: Server chose "
1120 "username/password authentication but we "
1122 PROXY_ERROR_GENERAL, 0);
1126 if (p->state == 6) {
1127 /* TODO: Handle CHAP authentication */
1128 plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
1129 PROXY_ERROR_GENERAL, 0);
1135 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1136 PROXY_ERROR_UNEXPECTED, 0);
1140 /* ----------------------------------------------------------------------
1141 * `Telnet' proxy type.
1143 * (This is for ad-hoc proxies where you connect to the proxy's
1144 * telnet port and send a command such as `connect host port'. The
1145 * command is configurable, since this proxy type is typically not
1146 * standardised or at all well-defined.)
1149 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1151 if (p->state == PROXY_CHANGE_NEW) {
1155 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1156 * %%, %host, %port, %user, and %pass
1159 while (cfg.proxy_telnet_command[eo] != 0) {
1161 /* scan forward until we hit end-of-line,
1162 * or an escape character (\ or %) */
1163 while (cfg.proxy_telnet_command[eo] != 0 &&
1164 cfg.proxy_telnet_command[eo] != '%' &&
1165 cfg.proxy_telnet_command[eo] != '\\') eo++;
1167 /* if we hit eol, break out of our escaping loop */
1168 if (cfg.proxy_telnet_command[eo] == 0) break;
1170 /* if there was any unescaped text before the escape
1171 * character, send that now */
1173 sk_write(p->sub_socket,
1174 cfg.proxy_telnet_command + so, eo - so);
1179 /* if the escape character was the last character of
1180 * the line, we'll just stop and send it. */
1181 if (cfg.proxy_telnet_command[eo] == 0) break;
1183 if (cfg.proxy_telnet_command[so] == '\\') {
1185 /* we recognize \\, \%, \r, \n, \t, \x??.
1186 * anything else, we just send unescaped (including the \).
1189 switch (cfg.proxy_telnet_command[eo]) {
1192 sk_write(p->sub_socket, "\\", 1);
1197 sk_write(p->sub_socket, "%%", 1);
1202 sk_write(p->sub_socket, "\r", 1);
1207 sk_write(p->sub_socket, "\n", 1);
1212 sk_write(p->sub_socket, "\t", 1);
1219 /* escaped hexadecimal value (ie. \xff) */
1220 unsigned char v = 0;
1225 if (cfg.proxy_telnet_command[eo] >= '0' &&
1226 cfg.proxy_telnet_command[eo] <= '9')
1227 v += cfg.proxy_telnet_command[eo] - '0';
1228 else if (cfg.proxy_telnet_command[eo] >= 'a' &&
1229 cfg.proxy_telnet_command[eo] <= 'f')
1230 v += cfg.proxy_telnet_command[eo] - 'a' + 10;
1231 else if (cfg.proxy_telnet_command[eo] >= 'A' &&
1232 cfg.proxy_telnet_command[eo] <= 'F')
1233 v += cfg.proxy_telnet_command[eo] - 'A' + 10;
1235 /* non hex character, so we abort and just
1236 * send the whole thing unescaped (including \x)
1238 sk_write(p->sub_socket, "\\", 1);
1243 /* we only extract two hex characters */
1245 sk_write(p->sub_socket, &v, 1);
1257 sk_write(p->sub_socket,
1258 cfg.proxy_telnet_command + so, 2);
1264 /* % escape. we recognize %%, %host, %port, %user, %pass.
1265 * anything else, we just send unescaped (including the %).
1268 if (cfg.proxy_telnet_command[eo] == '%') {
1269 sk_write(p->sub_socket, "%", 1);
1272 else if (strnicmp(cfg.proxy_telnet_command + eo,
1275 sk_getaddr(p->remote_addr, dest, lenof(dest));
1276 sk_write(p->sub_socket, dest, strlen(dest));
1279 else if (strnicmp(cfg.proxy_telnet_command + eo,
1282 sprintf(port, "%i", p->remote_port);
1283 sk_write(p->sub_socket, port, strlen(port));
1286 else if (strnicmp(cfg.proxy_telnet_command + eo,
1288 sk_write(p->sub_socket, cfg.proxy_username,
1289 strlen(cfg.proxy_username));
1292 else if (strnicmp(cfg.proxy_telnet_command + eo,
1294 sk_write(p->sub_socket, cfg.proxy_password,
1295 strlen(cfg.proxy_password));
1299 /* we don't escape this, so send the % now, and
1300 * don't advance eo, so that we'll consider the
1301 * text immediately following the % as unescaped.
1303 sk_write(p->sub_socket, "%", 1);
1307 /* resume scanning for additional escapes after this one. */
1311 /* if there is any unescaped text at the end of the line, send it */
1313 sk_write(p->sub_socket, cfg.proxy_telnet_command + so, eo - so);
1320 if (change == PROXY_CHANGE_CLOSING) {
1321 /* if our proxy negotiation process involves closing and opening
1322 * new sockets, then we would want to intercept this closing
1323 * callback when we were expecting it. if we aren't anticipating
1324 * a socket close, then some error must have occurred. we'll
1325 * just pass those errors up to the backend.
1327 return plug_closing(p->plug, p->closing_error_msg,
1328 p->closing_error_code,
1329 p->closing_calling_back);
1332 if (change == PROXY_CHANGE_SENT) {
1333 /* some (or all) of what we wrote to the proxy was sent.
1334 * we don't do anything new, however, until we receive the
1335 * proxy's response. we might want to set a timer so we can
1336 * timeout the proxy negotiation after a while...
1341 if (change == PROXY_CHANGE_ACCEPTING) {
1342 /* we should _never_ see this, as we are using our socket to
1343 * connect to a proxy, not accepting inbound connections.
1344 * what should we do? close the socket with an appropriate
1347 return plug_accepting(p->plug, p->accepting_sock);
1350 if (change == PROXY_CHANGE_RECEIVE) {
1351 /* we have received data from the underlying socket, which
1352 * we'll need to parse, process, and respond to appropriately.
1357 /* proxy activate will have dealt with
1358 * whatever is left of the buffer */
1362 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1363 PROXY_ERROR_UNEXPECTED, 0);