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(conf) \
18 (conf_get_int(conf, CONF_proxy_dns) == FORCE_ON || \
19 (conf_get_int(conf, CONF_proxy_dns) == AUTO && \
20 conf_get_int(conf, CONF_proxy_type) != PROXY_SOCKS4))
23 * Call this when proxy negotiation is complete, so that this
24 * socket can begin working normally.
26 void proxy_activate (Proxy_Socket p)
30 long output_before, output_after;
32 p->state = PROXY_STATE_ACTIVE;
34 /* we want to ignore new receive events until we have sent
35 * all of our buffered receive data.
37 sk_set_frozen(p->sub_socket, 1);
39 /* how many bytes of output have we buffered? */
40 output_before = bufchain_size(&p->pending_oob_output_data) +
41 bufchain_size(&p->pending_output_data);
42 /* and keep track of how many bytes do not get sent. */
45 /* send buffered OOB writes */
46 while (bufchain_size(&p->pending_oob_output_data) > 0) {
47 bufchain_prefix(&p->pending_oob_output_data, &data, &len);
48 output_after += sk_write_oob(p->sub_socket, data, len);
49 bufchain_consume(&p->pending_oob_output_data, len);
52 /* send buffered normal writes */
53 while (bufchain_size(&p->pending_output_data) > 0) {
54 bufchain_prefix(&p->pending_output_data, &data, &len);
55 output_after += sk_write(p->sub_socket, data, len);
56 bufchain_consume(&p->pending_output_data, len);
59 /* if we managed to send any data, let the higher levels know. */
60 if (output_after < output_before)
61 plug_sent(p->plug, output_after);
63 /* if we were asked to flush the output during
64 * the proxy negotiation process, do so now.
66 if (p->pending_flush) sk_flush(p->sub_socket);
68 /* if the backend wanted the socket unfrozen, try to unfreeze.
69 * our set_frozen handler will flush buffered receive data before
70 * unfreezing the actual underlying socket.
73 sk_set_frozen((Socket)p, 0);
76 /* basic proxy socket functions */
78 static Plug sk_proxy_plug (Socket s, Plug p)
80 Proxy_Socket ps = (Proxy_Socket) s;
87 static void sk_proxy_close (Socket s)
89 Proxy_Socket ps = (Proxy_Socket) s;
91 sk_close(ps->sub_socket);
92 sk_addr_free(ps->remote_addr);
96 static int sk_proxy_write (Socket s, const char *data, int len)
98 Proxy_Socket ps = (Proxy_Socket) s;
100 if (ps->state != PROXY_STATE_ACTIVE) {
101 bufchain_add(&ps->pending_output_data, data, len);
102 return bufchain_size(&ps->pending_output_data);
104 return sk_write(ps->sub_socket, data, len);
107 static int sk_proxy_write_oob (Socket s, const char *data, int len)
109 Proxy_Socket ps = (Proxy_Socket) s;
111 if (ps->state != PROXY_STATE_ACTIVE) {
112 bufchain_clear(&ps->pending_output_data);
113 bufchain_clear(&ps->pending_oob_output_data);
114 bufchain_add(&ps->pending_oob_output_data, data, len);
117 return sk_write_oob(ps->sub_socket, data, len);
120 static void sk_proxy_flush (Socket s)
122 Proxy_Socket ps = (Proxy_Socket) s;
124 if (ps->state != PROXY_STATE_ACTIVE) {
125 ps->pending_flush = 1;
128 sk_flush(ps->sub_socket);
131 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
133 Proxy_Socket ps = (Proxy_Socket) s;
134 sk_set_private_ptr(ps->sub_socket, ptr);
137 static void * sk_proxy_get_private_ptr (Socket s)
139 Proxy_Socket ps = (Proxy_Socket) s;
140 return sk_get_private_ptr(ps->sub_socket);
143 static void sk_proxy_set_frozen (Socket s, int is_frozen)
145 Proxy_Socket ps = (Proxy_Socket) s;
147 if (ps->state != PROXY_STATE_ACTIVE) {
148 ps->freeze = is_frozen;
152 /* handle any remaining buffered recv data first */
153 if (bufchain_size(&ps->pending_input_data) > 0) {
154 ps->freeze = is_frozen;
156 /* loop while we still have buffered data, and while we are
157 * unfrozen. the plug_receive call in the loop could result
158 * in a call back into this function refreezing the socket,
159 * so we have to check each time.
161 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
165 bufchain_prefix(&ps->pending_input_data, &data, &len);
166 if (len > lenof(databuf))
167 len = lenof(databuf);
168 memcpy(databuf, data, len);
169 bufchain_consume(&ps->pending_input_data, len);
170 plug_receive(ps->plug, 0, databuf, len);
173 /* if we're still frozen, we'll have to wait for another
174 * call from the backend to finish unbuffering the data.
176 if (ps->freeze) return;
179 sk_set_frozen(ps->sub_socket, is_frozen);
182 static const char * sk_proxy_socket_error (Socket s)
184 Proxy_Socket ps = (Proxy_Socket) s;
185 if (ps->error != NULL || ps->sub_socket == NULL) {
188 return sk_socket_error(ps->sub_socket);
191 /* basic proxy plug functions */
193 static void plug_proxy_log(Plug plug, int type, SockAddr addr, int port,
194 const char *error_msg, int error_code)
196 Proxy_Plug pp = (Proxy_Plug) plug;
197 Proxy_Socket ps = pp->proxy_socket;
199 plug_log(ps->plug, type, addr, port, error_msg, error_code);
202 static int plug_proxy_closing (Plug p, const char *error_msg,
203 int error_code, int calling_back)
205 Proxy_Plug pp = (Proxy_Plug) p;
206 Proxy_Socket ps = pp->proxy_socket;
208 if (ps->state != PROXY_STATE_ACTIVE) {
209 ps->closing_error_msg = error_msg;
210 ps->closing_error_code = error_code;
211 ps->closing_calling_back = calling_back;
212 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
214 return plug_closing(ps->plug, error_msg,
215 error_code, calling_back);
218 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
220 Proxy_Plug pp = (Proxy_Plug) p;
221 Proxy_Socket ps = pp->proxy_socket;
223 if (ps->state != PROXY_STATE_ACTIVE) {
224 /* we will lose the urgentness of this data, but since most,
225 * if not all, of this data will be consumed by the negotiation
226 * process, hopefully it won't affect the protocol above us
228 bufchain_add(&ps->pending_input_data, data, len);
229 ps->receive_urgent = urgent;
230 ps->receive_data = data;
231 ps->receive_len = len;
232 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
234 return plug_receive(ps->plug, urgent, data, len);
237 static void plug_proxy_sent (Plug p, int bufsize)
239 Proxy_Plug pp = (Proxy_Plug) p;
240 Proxy_Socket ps = pp->proxy_socket;
242 if (ps->state != PROXY_STATE_ACTIVE) {
243 ps->sent_bufsize = bufsize;
244 ps->negotiate(ps, PROXY_CHANGE_SENT);
247 plug_sent(ps->plug, bufsize);
250 static int plug_proxy_accepting (Plug p, OSSocket sock)
252 Proxy_Plug pp = (Proxy_Plug) p;
253 Proxy_Socket ps = pp->proxy_socket;
255 if (ps->state != PROXY_STATE_ACTIVE) {
256 ps->accepting_sock = sock;
257 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
259 return plug_accepting(ps->plug, sock);
263 * This function can accept a NULL pointer as `addr', in which case
264 * it will only check the host name.
266 static int proxy_for_destination (SockAddr addr, char *hostname, int port,
271 int hostip_len, hostname_len;
272 const char *exclude_list;
275 * Check the host name and IP against the hard-coded
276 * representations of `localhost'.
278 if (!conf_get_int(conf, CONF_even_proxy_localhost) &&
279 (sk_hostname_is_local(hostname) ||
280 (addr && sk_address_is_local(addr))))
281 return 0; /* do not proxy */
283 /* we want a string representation of the IP address for comparisons */
285 sk_getaddr(addr, hostip, 64);
286 hostip_len = strlen(hostip);
288 hostip_len = 0; /* placate gcc; shouldn't be required */
290 hostname_len = strlen(hostname);
292 exclude_list = conf_get_str(conf, CONF_proxy_exclude_list);
294 /* now parse the exclude list, and see if either our IP
295 * or hostname matches anything in it.
298 while (exclude_list[s]) {
299 while (exclude_list[s] &&
300 (isspace((unsigned char)exclude_list[s]) ||
301 exclude_list[s] == ',')) s++;
303 if (!exclude_list[s]) break;
307 while (exclude_list[e] &&
308 (isalnum((unsigned char)exclude_list[e]) ||
309 exclude_list[e] == '-' ||
310 exclude_list[e] == '.' ||
311 exclude_list[e] == '*')) e++;
313 if (exclude_list[s] == '*') {
314 /* wildcard at beginning of entry */
316 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
317 exclude_list + s + 1, e - s - 1) == 0) ||
318 strnicmp(hostname + hostname_len - (e - s - 1),
319 exclude_list + s + 1, e - s - 1) == 0)
320 return 0; /* IP/hostname range excluded. do not use proxy. */
322 } else if (exclude_list[e-1] == '*') {
323 /* wildcard at end of entry */
325 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
326 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
327 return 0; /* IP/hostname range excluded. do not use proxy. */
330 /* no wildcard at either end, so let's try an absolute
331 * match (ie. a specific IP)
334 if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
335 return 0; /* IP/hostname excluded. do not use proxy. */
336 if (strnicmp(hostname, exclude_list + s, e - s) == 0)
337 return 0; /* IP/hostname excluded. do not use proxy. */
342 /* Make sure we really have reached the next comma or end-of-string */
343 while (exclude_list[s] &&
344 !isspace((unsigned char)exclude_list[s]) &&
345 exclude_list[s] != ',') s++;
348 /* no matches in the exclude list, so use the proxy */
352 SockAddr name_lookup(char *host, int port, char **canonicalname,
353 Conf *conf, int addressfamily)
355 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
356 do_proxy_dns(conf) &&
357 proxy_for_destination(NULL, host, port, conf)) {
358 *canonicalname = dupstr(host);
359 return sk_nonamelookup(host);
362 return sk_namelookup(host, canonicalname, addressfamily);
365 Socket new_connection(SockAddr addr, char *hostname,
366 int port, int privport,
367 int oobinline, int nodelay, int keepalive,
368 Plug plug, Conf *conf)
370 static const struct socket_function_table socket_fn_table = {
376 sk_proxy_set_private_ptr,
377 sk_proxy_get_private_ptr,
379 sk_proxy_socket_error
382 static const struct plug_function_table plug_fn_table = {
390 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
391 proxy_for_destination(addr, hostname, port, conf))
396 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->conf = conf_copy(conf);
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 type = conf_get_int(conf, CONF_proxy_type);
426 if (type == PROXY_HTTP) {
427 ret->negotiate = proxy_http_negotiate;
428 } else if (type == PROXY_SOCKS4) {
429 ret->negotiate = proxy_socks4_negotiate;
430 } else if (type == PROXY_SOCKS5) {
431 ret->negotiate = proxy_socks5_negotiate;
432 } else if (type == PROXY_TELNET) {
433 ret->negotiate = proxy_telnet_negotiate;
435 ret->error = "Proxy error: Unknown proxy method";
439 /* create the proxy plug to map calls from the actual
440 * socket into our proxy socket layer */
441 pplug = snew(struct Plug_proxy_tag);
442 pplug->fn = &plug_fn_table;
443 pplug->proxy_socket = ret;
446 proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
447 &proxy_canonical_name,
448 conf_get_int(conf, CONF_addressfamily));
449 if (sk_addr_error(proxy_addr) != NULL) {
450 ret->error = "Proxy error: Unable to resolve proxy host name";
453 sfree(proxy_canonical_name);
455 /* create the actual socket we will be using,
456 * connected to our proxy server and port.
458 ret->sub_socket = sk_new(proxy_addr,
459 conf_get_int(conf, CONF_proxy_port),
461 nodelay, keepalive, (Plug) pplug);
462 if (sk_socket_error(ret->sub_socket) != NULL)
465 /* start the proxy negotiation process... */
466 sk_set_frozen(ret->sub_socket, 0);
467 ret->negotiate(ret, PROXY_CHANGE_NEW);
472 /* no proxy, so just return the direct socket */
473 return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
476 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
477 Conf *conf, int addressfamily)
479 /* TODO: SOCKS (and potentially others) support inbound
480 * TODO: connections via the proxy. support them.
483 return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
486 /* ----------------------------------------------------------------------
487 * HTTP CONNECT proxy type.
490 static int get_line_end (char * data, int len)
496 if (data[off] == '\n') {
497 /* we have a newline */
500 /* is that the only thing on this line? */
501 if (off <= 2) return off;
503 /* if not, then there is the possibility that this header
504 * continues onto the next line, if it starts with a space
509 data[off+1] != ' ' &&
510 data[off+1] != '\t') return off;
512 /* the line does continue, so we have to keep going
513 * until we see an the header's "real" end of line.
524 int proxy_http_negotiate (Proxy_Socket p, int change)
526 if (p->state == PROXY_STATE_NEW) {
527 /* we are just beginning the proxy negotiate process,
528 * so we'll send off the initial bits of the request.
529 * for this proxy method, it's just a simple HTTP
532 char *buf, dest[512];
533 char *username, *password;
535 sk_getaddr(p->remote_addr, dest, lenof(dest));
537 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
538 dest, p->remote_port, dest, p->remote_port);
539 sk_write(p->sub_socket, buf, strlen(buf));
542 username = conf_get_str(p->conf, CONF_proxy_username);
543 password = conf_get_str(p->conf, CONF_proxy_password);
544 if (username[0] || password[0]) {
547 buf = dupprintf("%s:%s", username, password);
549 buf2 = snewn(len * 4 / 3 + 100, char);
550 sprintf(buf2, "Proxy-Authorization: Basic ");
551 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
552 base64_encode_atom((unsigned char *)(buf+i),
553 (len-i > 3 ? 3 : len-i), buf2+j);
554 strcpy(buf2+j, "\r\n");
555 sk_write(p->sub_socket, buf2, strlen(buf2));
560 sk_write(p->sub_socket, "\r\n", 2);
566 if (change == PROXY_CHANGE_CLOSING) {
567 /* if our proxy negotiation process involves closing and opening
568 * new sockets, then we would want to intercept this closing
569 * callback when we were expecting it. if we aren't anticipating
570 * a socket close, then some error must have occurred. we'll
571 * just pass those errors up to the backend.
573 return plug_closing(p->plug, p->closing_error_msg,
574 p->closing_error_code,
575 p->closing_calling_back);
578 if (change == PROXY_CHANGE_SENT) {
579 /* some (or all) of what we wrote to the proxy was sent.
580 * we don't do anything new, however, until we receive the
581 * proxy's response. we might want to set a timer so we can
582 * timeout the proxy negotiation after a while...
587 if (change == PROXY_CHANGE_ACCEPTING) {
588 /* we should _never_ see this, as we are using our socket to
589 * connect to a proxy, not accepting inbound connections.
590 * what should we do? close the socket with an appropriate
593 return plug_accepting(p->plug, p->accepting_sock);
596 if (change == PROXY_CHANGE_RECEIVE) {
597 /* we have received data from the underlying socket, which
598 * we'll need to parse, process, and respond to appropriately.
607 int min_ver, maj_ver, status;
609 /* get the status line */
610 len = bufchain_size(&p->pending_input_data);
611 assert(len > 0); /* or we wouldn't be here */
612 data = snewn(len+1, char);
613 bufchain_fetch(&p->pending_input_data, data, len);
615 * We must NUL-terminate this data, because Windows
616 * sscanf appears to require a NUL at the end of the
617 * string because it strlens it _first_. Sigh.
621 eol = get_line_end(data, len);
628 /* We can't rely on whether the %n incremented the sscanf return */
629 if (sscanf((char *)data, "HTTP/%i.%i %n",
630 &maj_ver, &min_ver, &status) < 2 || status == -1) {
631 plug_closing(p->plug, "Proxy error: HTTP response was absent",
632 PROXY_ERROR_GENERAL, 0);
637 /* remove the status line from the input buffer. */
638 bufchain_consume(&p->pending_input_data, eol);
639 if (data[status] != '2') {
643 while (eol > status &&
644 (data[eol-1] == '\r' || data[eol-1] == '\n'))
646 buf = dupprintf("Proxy error: %s", data+status);
647 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
660 /* get headers. we're done when we get a
661 * header of length 2, (ie. just "\r\n")
664 len = bufchain_size(&p->pending_input_data);
665 assert(len > 0); /* or we wouldn't be here */
666 data = snewn(len, char);
668 bufchain_fetch(&p->pending_input_data, data, len);
670 eol = get_line_end(datap, len);
677 bufchain_consume(&p->pending_input_data, eol);
680 eol = get_line_end(datap, len);
685 bufchain_consume(&p->pending_input_data, 2);
687 /* proxy activate will have dealt with
688 * whatever is left of the buffer */
698 plug_closing(p->plug, "Proxy error: unexpected proxy error",
699 PROXY_ERROR_UNEXPECTED, 0);
703 /* ----------------------------------------------------------------------
707 /* SOCKS version 4 */
708 int proxy_socks4_negotiate (Proxy_Socket p, int change)
710 if (p->state == PROXY_CHANGE_NEW) {
713 * version number (1 byte) = 4
714 * command code (1 byte)
717 * dest. port (2 bytes) [network order]
718 * dest. address (4 bytes)
719 * user ID (variable length, null terminated string)
722 int length, type, namelen;
723 char *command, addr[4], hostname[512];
726 type = sk_addrtype(p->remote_addr);
727 if (type == ADDRTYPE_IPV6) {
728 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
729 " not support IPv6", PROXY_ERROR_GENERAL, 0);
731 } else if (type == ADDRTYPE_IPV4) {
733 sk_addrcopy(p->remote_addr, addr);
734 } else { /* type == ADDRTYPE_NAME */
735 assert(type == ADDRTYPE_NAME);
736 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
737 namelen = strlen(hostname) + 1; /* include the NUL */
738 addr[0] = addr[1] = addr[2] = 0;
742 username = conf_get_str(p->conf, CONF_proxy_username);
743 length = strlen(username) + namelen + 9;
744 command = snewn(length, char);
745 strcpy(command + 8, username);
747 command[0] = 4; /* version 4 */
748 command[1] = 1; /* CONNECT command */
751 command[2] = (char) (p->remote_port >> 8) & 0xff;
752 command[3] = (char) p->remote_port & 0xff;
755 memcpy(command + 4, addr, 4);
758 memcpy(command + 8 + strlen(username) + 1,
761 sk_write(p->sub_socket, command, length);
769 if (change == PROXY_CHANGE_CLOSING) {
770 /* if our proxy negotiation process involves closing and opening
771 * new sockets, then we would want to intercept this closing
772 * callback when we were expecting it. if we aren't anticipating
773 * a socket close, then some error must have occurred. we'll
774 * just pass those errors up to the backend.
776 return plug_closing(p->plug, p->closing_error_msg,
777 p->closing_error_code,
778 p->closing_calling_back);
781 if (change == PROXY_CHANGE_SENT) {
782 /* some (or all) of what we wrote to the proxy was sent.
783 * we don't do anything new, however, until we receive the
784 * proxy's response. we might want to set a timer so we can
785 * timeout the proxy negotiation after a while...
790 if (change == PROXY_CHANGE_ACCEPTING) {
791 /* we should _never_ see this, as we are using our socket to
792 * connect to a proxy, not accepting inbound connections.
793 * what should we do? close the socket with an appropriate
796 return plug_accepting(p->plug, p->accepting_sock);
799 if (change == PROXY_CHANGE_RECEIVE) {
800 /* we have received data from the underlying socket, which
801 * we'll need to parse, process, and respond to appropriately.
806 * version number (1 byte) = 4
807 * reply code (1 byte)
808 * 90 = request granted
809 * 91 = request rejected or failed
810 * 92 = request rejected due to lack of IDENTD on client
811 * 93 = request rejected due to difference in user ID
812 * (what we sent vs. what IDENTD said)
813 * dest. port (2 bytes)
814 * dest. address (4 bytes)
819 if (bufchain_size(&p->pending_input_data) < 8)
820 return 1; /* not got anything yet */
822 /* get the response */
823 bufchain_fetch(&p->pending_input_data, data, 8);
826 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
827 "unexpected reply code version",
828 PROXY_ERROR_GENERAL, 0);
836 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
837 PROXY_ERROR_GENERAL, 0);
840 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
841 PROXY_ERROR_GENERAL, 0);
845 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
846 PROXY_ERROR_GENERAL, 0);
852 bufchain_consume(&p->pending_input_data, 8);
856 /* proxy activate will have dealt with
857 * whatever is left of the buffer */
862 plug_closing(p->plug, "Proxy error: unexpected proxy error",
863 PROXY_ERROR_UNEXPECTED, 0);
867 /* SOCKS version 5 */
868 int proxy_socks5_negotiate (Proxy_Socket p, int change)
870 if (p->state == PROXY_CHANGE_NEW) {
873 * version number (1 byte) = 5
874 * number of available authentication methods (1 byte)
875 * available authentication methods (1 byte * previous value)
876 * authentication methods:
877 * 0x00 = no authentication
879 * 0x02 = username/password
884 char *username, *password;
887 command[0] = 5; /* version 5 */
888 username = conf_get_str(p->conf, CONF_proxy_username);
889 password = conf_get_str(p->conf, CONF_proxy_password);
890 if (username[0] || password[0]) {
891 command[2] = 0x00; /* no authentication */
893 proxy_socks5_offerencryptedauth (command, &len);
894 command[len++] = 0x02; /* username/password */
895 command[1] = len - 2; /* Number of methods supported */
897 command[1] = 1; /* one methods supported: */
898 command[2] = 0x00; /* no authentication */
902 sk_write(p->sub_socket, command, len);
908 if (change == PROXY_CHANGE_CLOSING) {
909 /* if our proxy negotiation process involves closing and opening
910 * new sockets, then we would want to intercept this closing
911 * callback when we were expecting it. if we aren't anticipating
912 * a socket close, then some error must have occurred. we'll
913 * just pass those errors up to the backend.
915 return plug_closing(p->plug, p->closing_error_msg,
916 p->closing_error_code,
917 p->closing_calling_back);
920 if (change == PROXY_CHANGE_SENT) {
921 /* some (or all) of what we wrote to the proxy was sent.
922 * we don't do anything new, however, until we receive the
923 * proxy's response. we might want to set a timer so we can
924 * timeout the proxy negotiation after a while...
929 if (change == PROXY_CHANGE_ACCEPTING) {
930 /* we should _never_ see this, as we are using our socket to
931 * connect to a proxy, not accepting inbound connections.
932 * what should we do? close the socket with an appropriate
935 return plug_accepting(p->plug, p->accepting_sock);
938 if (change == PROXY_CHANGE_RECEIVE) {
939 /* we have received data from the underlying socket, which
940 * we'll need to parse, process, and respond to appropriately.
946 * version number (1 byte) = 5
947 * authentication method (1 byte)
948 * authentication methods:
949 * 0x00 = no authentication
951 * 0x02 = username/password
953 * 0xff = no acceptable methods
957 if (bufchain_size(&p->pending_input_data) < 2)
958 return 1; /* not got anything yet */
960 /* get the response */
961 bufchain_fetch(&p->pending_input_data, data, 2);
964 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
965 PROXY_ERROR_GENERAL, 0);
969 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
970 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
971 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
972 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
974 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
975 PROXY_ERROR_GENERAL, 0);
978 bufchain_consume(&p->pending_input_data, 2);
983 /* password authentication reply format:
984 * version number (1 bytes) = 1
985 * reply code (1 byte)
991 if (bufchain_size(&p->pending_input_data) < 2)
992 return 1; /* not got anything yet */
994 /* get the response */
995 bufchain_fetch(&p->pending_input_data, data, 2);
998 plug_closing(p->plug, "Proxy error: SOCKS password "
999 "subnegotiation contained wrong version number",
1000 PROXY_ERROR_GENERAL, 0);
1006 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
1007 " password authentication",
1008 PROXY_ERROR_GENERAL, 0);
1012 bufchain_consume(&p->pending_input_data, 2);
1013 p->state = 2; /* now proceed as authenticated */
1016 if (p->state == 8) {
1018 ret = proxy_socks5_handlechap(p);
1019 if (ret) return ret;
1022 if (p->state == 2) {
1025 * version number (1 byte) = 5
1026 * command code (1 byte)
1030 * reserved (1 byte) = 0x00
1031 * address type (1 byte)
1033 * 3 = domainname (first byte has length, no terminating null)
1035 * dest. address (variable)
1036 * dest. port (2 bytes) [network order]
1043 type = sk_addrtype(p->remote_addr);
1044 if (type == ADDRTYPE_IPV4) {
1045 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1046 command[3] = 1; /* IPv4 */
1047 sk_addrcopy(p->remote_addr, command+4);
1048 } else if (type == ADDRTYPE_IPV6) {
1049 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1050 command[3] = 4; /* IPv6 */
1051 sk_addrcopy(p->remote_addr, command+4);
1053 assert(type == ADDRTYPE_NAME);
1055 sk_getaddr(p->remote_addr, command+5, 256);
1056 command[4] = strlen(command+5);
1057 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1060 command[0] = 5; /* version 5 */
1061 command[1] = 1; /* CONNECT command */
1065 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1066 command[len-1] = (char) p->remote_port & 0xff;
1068 sk_write(p->sub_socket, command, len);
1074 if (p->state == 3) {
1077 * version number (1 bytes) = 5
1078 * reply code (1 byte)
1080 * 1 = general SOCKS server failure
1081 * 2 = connection not allowed by ruleset
1082 * 3 = network unreachable
1083 * 4 = host unreachable
1084 * 5 = connection refused
1086 * 7 = command not supported
1087 * 8 = address type not supported
1088 * reserved (1 byte) = x00
1089 * address type (1 byte)
1091 * 3 = domainname (first byte has length, no terminating null)
1093 * server bound address (variable)
1094 * server bound port (2 bytes) [network order]
1099 /* First 5 bytes of packet are enough to tell its length. */
1100 if (bufchain_size(&p->pending_input_data) < 5)
1101 return 1; /* not got anything yet */
1103 /* get the response */
1104 bufchain_fetch(&p->pending_input_data, data, 5);
1107 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1108 PROXY_ERROR_GENERAL, 0);
1115 strcpy(buf, "Proxy error: ");
1118 case 1: strcat(buf, "General SOCKS server failure"); break;
1119 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1120 case 3: strcat(buf, "Network unreachable"); break;
1121 case 4: strcat(buf, "Host unreachable"); break;
1122 case 5: strcat(buf, "Connection refused"); break;
1123 case 6: strcat(buf, "TTL expired"); break;
1124 case 7: strcat(buf, "Command not supported"); break;
1125 case 8: strcat(buf, "Address type not supported"); break;
1126 default: sprintf(buf+strlen(buf),
1127 "Unrecognised SOCKS error code %d",
1131 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1137 * Eat the rest of the reply packet.
1139 len = 6; /* first 4 bytes, last 2 */
1141 case 1: len += 4; break; /* IPv4 address */
1142 case 4: len += 16; break;/* IPv6 address */
1143 case 3: len += (unsigned char)data[4]; break; /* domain name */
1145 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1146 "unrecognised address format",
1147 PROXY_ERROR_GENERAL, 0);
1150 if (bufchain_size(&p->pending_input_data) < len)
1151 return 1; /* not got whole reply yet */
1152 bufchain_consume(&p->pending_input_data, len);
1159 if (p->state == 4) {
1160 /* TODO: Handle GSSAPI authentication */
1161 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1162 PROXY_ERROR_GENERAL, 0);
1166 if (p->state == 5) {
1167 char *username = conf_get_str(p->conf, CONF_proxy_username);
1168 char *password = conf_get_str(p->conf, CONF_proxy_password);
1169 if (username[0] || password[0]) {
1170 char userpwbuf[255 + 255 + 3];
1172 ulen = strlen(username);
1173 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1174 plen = strlen(password);
1175 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1176 userpwbuf[0] = 1; /* version number of subnegotiation */
1177 userpwbuf[1] = ulen;
1178 memcpy(userpwbuf+2, username, ulen);
1179 userpwbuf[ulen+2] = plen;
1180 memcpy(userpwbuf+ulen+3, password, plen);
1181 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1184 plug_closing(p->plug, "Proxy error: Server chose "
1185 "username/password authentication but we "
1187 PROXY_ERROR_GENERAL, 0);
1191 if (p->state == 6) {
1193 ret = proxy_socks5_selectchap(p);
1194 if (ret) return ret;
1199 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1200 PROXY_ERROR_UNEXPECTED, 0);
1204 /* ----------------------------------------------------------------------
1205 * `Telnet' proxy type.
1207 * (This is for ad-hoc proxies where you connect to the proxy's
1208 * telnet port and send a command such as `connect host port'. The
1209 * command is configurable, since this proxy type is typically not
1210 * standardised or at all well-defined.)
1213 char *format_telnet_command(SockAddr addr, int port, Conf *conf)
1215 char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
1217 int retlen = 0, retsize = 0;
1219 #define ENSURE(n) do { \
1220 if (retsize < retlen + n) { \
1221 retsize = retlen + n + 512; \
1222 ret = sresize(ret, retsize, char); \
1226 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1227 * %%, %host, %port, %user, and %pass
1230 while (fmt[eo] != 0) {
1232 /* scan forward until we hit end-of-line,
1233 * or an escape character (\ or %) */
1234 while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
1237 /* if we hit eol, break out of our escaping loop */
1238 if (fmt[eo] == 0) break;
1240 /* if there was any unescaped text before the escape
1241 * character, send that now */
1244 memcpy(ret + retlen, fmt + so, eo - so);
1250 /* if the escape character was the last character of
1251 * the line, we'll just stop and send it. */
1252 if (fmt[eo] == 0) break;
1254 if (fmt[so] == '\\') {
1256 /* we recognize \\, \%, \r, \n, \t, \x??.
1257 * anything else, we just send unescaped (including the \).
1264 ret[retlen++] = '\\';
1270 ret[retlen++] = '%';
1276 ret[retlen++] = '\r';
1282 ret[retlen++] = '\n';
1288 ret[retlen++] = '\t';
1295 /* escaped hexadecimal value (ie. \xff) */
1296 unsigned char v = 0;
1301 if (fmt[eo] >= '0' && fmt[eo] <= '9')
1303 else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
1304 v += fmt[eo] - 'a' + 10;
1305 else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
1306 v += fmt[eo] - 'A' + 10;
1308 /* non hex character, so we abort and just
1309 * send the whole thing unescaped (including \x)
1312 ret[retlen++] = '\\';
1317 /* we only extract two hex characters */
1333 memcpy(ret+retlen, fmt + so, 2);
1340 /* % escape. we recognize %%, %host, %port, %user, %pass.
1341 * %proxyhost, %proxyport. Anything else we just send
1342 * unescaped (including the %).
1345 if (fmt[eo] == '%') {
1347 ret[retlen++] = '%';
1350 else if (strnicmp(fmt + eo, "host", 4) == 0) {
1353 sk_getaddr(addr, dest, lenof(dest));
1354 destlen = strlen(dest);
1356 memcpy(ret+retlen, dest, destlen);
1360 else if (strnicmp(fmt + eo, "port", 4) == 0) {
1361 char portstr[8], portlen;
1362 portlen = sprintf(portstr, "%i", port);
1364 memcpy(ret + retlen, portstr, portlen);
1368 else if (strnicmp(fmt + eo, "user", 4) == 0) {
1369 char *username = conf_get_str(conf, CONF_proxy_username);
1370 int userlen = strlen(username);
1372 memcpy(ret+retlen, username, userlen);
1376 else if (strnicmp(fmt + eo, "pass", 4) == 0) {
1377 char *password = conf_get_str(conf, CONF_proxy_password);
1378 int passlen = strlen(password);
1380 memcpy(ret+retlen, password, passlen);
1384 else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
1385 char *host = conf_get_str(conf, CONF_proxy_host);
1386 int phlen = strlen(host);
1388 memcpy(ret+retlen, host, phlen);
1392 else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
1393 int port = conf_get_int(conf, CONF_proxy_port);
1396 sprintf(pport, "%d", port);
1397 pplen = strlen(pport);
1399 memcpy(ret+retlen, pport, pplen);
1404 /* we don't escape this, so send the % now, and
1405 * don't advance eo, so that we'll consider the
1406 * text immediately following the % as unescaped.
1409 ret[retlen++] = '%';
1413 /* resume scanning for additional escapes after this one. */
1417 /* if there is any unescaped text at the end of the line, send it */
1420 memcpy(ret + retlen, fmt + so, eo - so);
1431 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1433 if (p->state == PROXY_CHANGE_NEW) {
1434 char *formatted_cmd;
1436 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1439 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1440 sfree(formatted_cmd);
1446 if (change == PROXY_CHANGE_CLOSING) {
1447 /* if our proxy negotiation process involves closing and opening
1448 * new sockets, then we would want to intercept this closing
1449 * callback when we were expecting it. if we aren't anticipating
1450 * a socket close, then some error must have occurred. we'll
1451 * just pass those errors up to the backend.
1453 return plug_closing(p->plug, p->closing_error_msg,
1454 p->closing_error_code,
1455 p->closing_calling_back);
1458 if (change == PROXY_CHANGE_SENT) {
1459 /* some (or all) of what we wrote to the proxy was sent.
1460 * we don't do anything new, however, until we receive the
1461 * proxy's response. we might want to set a timer so we can
1462 * timeout the proxy negotiation after a while...
1467 if (change == PROXY_CHANGE_ACCEPTING) {
1468 /* we should _never_ see this, as we are using our socket to
1469 * connect to a proxy, not accepting inbound connections.
1470 * what should we do? close the socket with an appropriate
1473 return plug_accepting(p->plug, p->accepting_sock);
1476 if (change == PROXY_CHANGE_RECEIVE) {
1477 /* we have received data from the underlying socket, which
1478 * we'll need to parse, process, and respond to appropriately.
1483 /* proxy activate will have dealt with
1484 * whatever is left of the buffer */
1488 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1489 PROXY_ERROR_UNEXPECTED, 0);