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 we have a pending EOF to send, send it */
69 if (p->pending_eof) sk_write_eof(p->sub_socket);
71 /* if the backend wanted the socket unfrozen, try to unfreeze.
72 * our set_frozen handler will flush buffered receive data before
73 * unfreezing the actual underlying socket.
76 sk_set_frozen((Socket)p, 0);
79 /* basic proxy socket functions */
81 static Plug sk_proxy_plug (Socket s, Plug p)
83 Proxy_Socket ps = (Proxy_Socket) s;
90 static void sk_proxy_close (Socket s)
92 Proxy_Socket ps = (Proxy_Socket) s;
94 sk_close(ps->sub_socket);
95 sk_addr_free(ps->remote_addr);
99 static int sk_proxy_write (Socket s, const char *data, int len)
101 Proxy_Socket ps = (Proxy_Socket) s;
103 if (ps->state != PROXY_STATE_ACTIVE) {
104 bufchain_add(&ps->pending_output_data, data, len);
105 return bufchain_size(&ps->pending_output_data);
107 return sk_write(ps->sub_socket, data, len);
110 static int sk_proxy_write_oob (Socket s, const char *data, int len)
112 Proxy_Socket ps = (Proxy_Socket) s;
114 if (ps->state != PROXY_STATE_ACTIVE) {
115 bufchain_clear(&ps->pending_output_data);
116 bufchain_clear(&ps->pending_oob_output_data);
117 bufchain_add(&ps->pending_oob_output_data, data, len);
120 return sk_write_oob(ps->sub_socket, data, len);
123 static void sk_proxy_write_eof (Socket s)
125 Proxy_Socket ps = (Proxy_Socket) s;
127 if (ps->state != PROXY_STATE_ACTIVE) {
131 sk_write_eof(ps->sub_socket);
134 static void sk_proxy_flush (Socket s)
136 Proxy_Socket ps = (Proxy_Socket) s;
138 if (ps->state != PROXY_STATE_ACTIVE) {
139 ps->pending_flush = 1;
142 sk_flush(ps->sub_socket);
145 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
147 Proxy_Socket ps = (Proxy_Socket) s;
148 sk_set_private_ptr(ps->sub_socket, ptr);
151 static void * sk_proxy_get_private_ptr (Socket s)
153 Proxy_Socket ps = (Proxy_Socket) s;
154 return sk_get_private_ptr(ps->sub_socket);
157 static void sk_proxy_set_frozen (Socket s, int is_frozen)
159 Proxy_Socket ps = (Proxy_Socket) s;
161 if (ps->state != PROXY_STATE_ACTIVE) {
162 ps->freeze = is_frozen;
166 /* handle any remaining buffered recv data first */
167 if (bufchain_size(&ps->pending_input_data) > 0) {
168 ps->freeze = is_frozen;
170 /* loop while we still have buffered data, and while we are
171 * unfrozen. the plug_receive call in the loop could result
172 * in a call back into this function refreezing the socket,
173 * so we have to check each time.
175 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
179 bufchain_prefix(&ps->pending_input_data, &data, &len);
180 if (len > lenof(databuf))
181 len = lenof(databuf);
182 memcpy(databuf, data, len);
183 bufchain_consume(&ps->pending_input_data, len);
184 plug_receive(ps->plug, 0, databuf, len);
187 /* if we're still frozen, we'll have to wait for another
188 * call from the backend to finish unbuffering the data.
190 if (ps->freeze) return;
193 sk_set_frozen(ps->sub_socket, is_frozen);
196 static const char * sk_proxy_socket_error (Socket s)
198 Proxy_Socket ps = (Proxy_Socket) s;
199 if (ps->error != NULL || ps->sub_socket == NULL) {
202 return sk_socket_error(ps->sub_socket);
205 /* basic proxy plug functions */
207 static void plug_proxy_log(Plug plug, int type, SockAddr addr, int port,
208 const char *error_msg, int error_code)
210 Proxy_Plug pp = (Proxy_Plug) plug;
211 Proxy_Socket ps = pp->proxy_socket;
213 plug_log(ps->plug, type, addr, port, error_msg, error_code);
216 static int plug_proxy_closing (Plug p, const char *error_msg,
217 int error_code, int calling_back)
219 Proxy_Plug pp = (Proxy_Plug) p;
220 Proxy_Socket ps = pp->proxy_socket;
222 if (ps->state != PROXY_STATE_ACTIVE) {
223 ps->closing_error_msg = error_msg;
224 ps->closing_error_code = error_code;
225 ps->closing_calling_back = calling_back;
226 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
228 return plug_closing(ps->plug, error_msg,
229 error_code, calling_back);
232 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
234 Proxy_Plug pp = (Proxy_Plug) p;
235 Proxy_Socket ps = pp->proxy_socket;
237 if (ps->state != PROXY_STATE_ACTIVE) {
238 /* we will lose the urgentness of this data, but since most,
239 * if not all, of this data will be consumed by the negotiation
240 * process, hopefully it won't affect the protocol above us
242 bufchain_add(&ps->pending_input_data, data, len);
243 ps->receive_urgent = urgent;
244 ps->receive_data = data;
245 ps->receive_len = len;
246 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
248 return plug_receive(ps->plug, urgent, data, len);
251 static void plug_proxy_sent (Plug p, int bufsize)
253 Proxy_Plug pp = (Proxy_Plug) p;
254 Proxy_Socket ps = pp->proxy_socket;
256 if (ps->state != PROXY_STATE_ACTIVE) {
257 ps->sent_bufsize = bufsize;
258 ps->negotiate(ps, PROXY_CHANGE_SENT);
261 plug_sent(ps->plug, bufsize);
264 static int plug_proxy_accepting(Plug p,
265 accept_fn_t constructor, accept_ctx_t ctx)
267 Proxy_Plug pp = (Proxy_Plug) p;
268 Proxy_Socket ps = pp->proxy_socket;
270 if (ps->state != PROXY_STATE_ACTIVE) {
271 ps->accepting_constructor = constructor;
272 ps->accepting_ctx = ctx;
273 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
275 return plug_accepting(ps->plug, constructor, ctx);
279 * This function can accept a NULL pointer as `addr', in which case
280 * it will only check the host name.
282 static int proxy_for_destination (SockAddr addr, const char *hostname,
283 int port, Conf *conf)
287 int hostip_len, hostname_len;
288 const char *exclude_list;
291 * Special local connections such as Unix-domain sockets
292 * unconditionally cannot be proxied, even in proxy-localhost
293 * mode. There just isn't any way to ask any known proxy type for
296 if (addr && sk_address_is_special_local(addr))
297 return 0; /* do not proxy */
300 * Check the host name and IP against the hard-coded
301 * representations of `localhost'.
303 if (!conf_get_int(conf, CONF_even_proxy_localhost) &&
304 (sk_hostname_is_local(hostname) ||
305 (addr && sk_address_is_local(addr))))
306 return 0; /* do not proxy */
308 /* we want a string representation of the IP address for comparisons */
310 sk_getaddr(addr, hostip, 64);
311 hostip_len = strlen(hostip);
313 hostip_len = 0; /* placate gcc; shouldn't be required */
315 hostname_len = strlen(hostname);
317 exclude_list = conf_get_str(conf, CONF_proxy_exclude_list);
319 /* now parse the exclude list, and see if either our IP
320 * or hostname matches anything in it.
323 while (exclude_list[s]) {
324 while (exclude_list[s] &&
325 (isspace((unsigned char)exclude_list[s]) ||
326 exclude_list[s] == ',')) s++;
328 if (!exclude_list[s]) break;
332 while (exclude_list[e] &&
333 (isalnum((unsigned char)exclude_list[e]) ||
334 exclude_list[e] == '-' ||
335 exclude_list[e] == '.' ||
336 exclude_list[e] == '*')) e++;
338 if (exclude_list[s] == '*') {
339 /* wildcard at beginning of entry */
341 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
342 exclude_list + s + 1, e - s - 1) == 0) ||
343 strnicmp(hostname + hostname_len - (e - s - 1),
344 exclude_list + s + 1, e - s - 1) == 0)
345 return 0; /* IP/hostname range excluded. do not use proxy. */
347 } else if (exclude_list[e-1] == '*') {
348 /* wildcard at end of entry */
350 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
351 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
352 return 0; /* IP/hostname range excluded. do not use proxy. */
355 /* no wildcard at either end, so let's try an absolute
356 * match (ie. a specific IP)
359 if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
360 return 0; /* IP/hostname excluded. do not use proxy. */
361 if (strnicmp(hostname, exclude_list + s, e - s) == 0)
362 return 0; /* IP/hostname excluded. do not use proxy. */
367 /* Make sure we really have reached the next comma or end-of-string */
368 while (exclude_list[s] &&
369 !isspace((unsigned char)exclude_list[s]) &&
370 exclude_list[s] != ',') s++;
373 /* no matches in the exclude list, so use the proxy */
377 SockAddr name_lookup(char *host, int port, char **canonicalname,
378 Conf *conf, int addressfamily)
380 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
381 do_proxy_dns(conf) &&
382 proxy_for_destination(NULL, host, port, conf)) {
383 *canonicalname = dupstr(host);
384 return sk_nonamelookup(host);
387 return sk_namelookup(host, canonicalname, addressfamily);
390 Socket new_connection(SockAddr addr, char *hostname,
391 int port, int privport,
392 int oobinline, int nodelay, int keepalive,
393 Plug plug, Conf *conf)
395 static const struct socket_function_table socket_fn_table = {
402 sk_proxy_set_private_ptr,
403 sk_proxy_get_private_ptr,
405 sk_proxy_socket_error
408 static const struct plug_function_table plug_fn_table = {
416 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
417 proxy_for_destination(addr, hostname, port, conf))
422 char *proxy_canonical_name;
426 if ((sret = platform_new_connection(addr, hostname, port, privport,
427 oobinline, nodelay, keepalive,
432 ret = snew(struct Socket_proxy_tag);
433 ret->fn = &socket_fn_table;
434 ret->conf = conf_copy(conf);
436 ret->remote_addr = addr; /* will need to be freed on close */
437 ret->remote_port = port;
440 ret->pending_flush = 0;
441 ret->pending_eof = 0;
444 bufchain_init(&ret->pending_input_data);
445 bufchain_init(&ret->pending_output_data);
446 bufchain_init(&ret->pending_oob_output_data);
448 ret->sub_socket = NULL;
449 ret->state = PROXY_STATE_NEW;
450 ret->negotiate = NULL;
452 type = conf_get_int(conf, CONF_proxy_type);
453 if (type == PROXY_HTTP) {
454 ret->negotiate = proxy_http_negotiate;
455 } else if (type == PROXY_SOCKS4) {
456 ret->negotiate = proxy_socks4_negotiate;
457 } else if (type == PROXY_SOCKS5) {
458 ret->negotiate = proxy_socks5_negotiate;
459 } else if (type == PROXY_TELNET) {
460 ret->negotiate = proxy_telnet_negotiate;
462 ret->error = "Proxy error: Unknown proxy method";
466 /* create the proxy plug to map calls from the actual
467 * socket into our proxy socket layer */
468 pplug = snew(struct Plug_proxy_tag);
469 pplug->fn = &plug_fn_table;
470 pplug->proxy_socket = ret;
473 proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
474 &proxy_canonical_name,
475 conf_get_int(conf, CONF_addressfamily));
476 if (sk_addr_error(proxy_addr) != NULL) {
477 ret->error = "Proxy error: Unable to resolve proxy host name";
479 sk_addr_free(proxy_addr);
482 sfree(proxy_canonical_name);
484 /* create the actual socket we will be using,
485 * connected to our proxy server and port.
487 ret->sub_socket = sk_new(proxy_addr,
488 conf_get_int(conf, CONF_proxy_port),
490 nodelay, keepalive, (Plug) pplug);
491 if (sk_socket_error(ret->sub_socket) != NULL)
494 /* start the proxy negotiation process... */
495 sk_set_frozen(ret->sub_socket, 0);
496 ret->negotiate(ret, PROXY_CHANGE_NEW);
501 /* no proxy, so just return the direct socket */
502 return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
505 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
506 Conf *conf, int addressfamily)
508 /* TODO: SOCKS (and potentially others) support inbound
509 * TODO: connections via the proxy. support them.
512 return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
515 /* ----------------------------------------------------------------------
516 * HTTP CONNECT proxy type.
519 static int get_line_end (char * data, int len)
525 if (data[off] == '\n') {
526 /* we have a newline */
529 /* is that the only thing on this line? */
530 if (off <= 2) return off;
532 /* if not, then there is the possibility that this header
533 * continues onto the next line, if it starts with a space
538 data[off+1] != ' ' &&
539 data[off+1] != '\t') return off;
541 /* the line does continue, so we have to keep going
542 * until we see an the header's "real" end of line.
553 int proxy_http_negotiate (Proxy_Socket p, int change)
555 if (p->state == PROXY_STATE_NEW) {
556 /* we are just beginning the proxy negotiate process,
557 * so we'll send off the initial bits of the request.
558 * for this proxy method, it's just a simple HTTP
561 char *buf, dest[512];
562 char *username, *password;
564 sk_getaddr(p->remote_addr, dest, lenof(dest));
566 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
567 dest, p->remote_port, dest, p->remote_port);
568 sk_write(p->sub_socket, buf, strlen(buf));
571 username = conf_get_str(p->conf, CONF_proxy_username);
572 password = conf_get_str(p->conf, CONF_proxy_password);
573 if (username[0] || password[0]) {
576 buf = dupprintf("%s:%s", username, password);
578 buf2 = snewn(len * 4 / 3 + 100, char);
579 sprintf(buf2, "Proxy-Authorization: Basic ");
580 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
581 base64_encode_atom((unsigned char *)(buf+i),
582 (len-i > 3 ? 3 : len-i), buf2+j);
583 strcpy(buf2+j, "\r\n");
584 sk_write(p->sub_socket, buf2, strlen(buf2));
589 sk_write(p->sub_socket, "\r\n", 2);
595 if (change == PROXY_CHANGE_CLOSING) {
596 /* if our proxy negotiation process involves closing and opening
597 * new sockets, then we would want to intercept this closing
598 * callback when we were expecting it. if we aren't anticipating
599 * a socket close, then some error must have occurred. we'll
600 * just pass those errors up to the backend.
602 return plug_closing(p->plug, p->closing_error_msg,
603 p->closing_error_code,
604 p->closing_calling_back);
607 if (change == PROXY_CHANGE_SENT) {
608 /* some (or all) of what we wrote to the proxy was sent.
609 * we don't do anything new, however, until we receive the
610 * proxy's response. we might want to set a timer so we can
611 * timeout the proxy negotiation after a while...
616 if (change == PROXY_CHANGE_ACCEPTING) {
617 /* we should _never_ see this, as we are using our socket to
618 * connect to a proxy, not accepting inbound connections.
619 * what should we do? close the socket with an appropriate
622 return plug_accepting(p->plug,
623 p->accepting_constructor, p->accepting_ctx);
626 if (change == PROXY_CHANGE_RECEIVE) {
627 /* we have received data from the underlying socket, which
628 * we'll need to parse, process, and respond to appropriately.
637 int min_ver, maj_ver, status;
639 /* get the status line */
640 len = bufchain_size(&p->pending_input_data);
641 assert(len > 0); /* or we wouldn't be here */
642 data = snewn(len+1, char);
643 bufchain_fetch(&p->pending_input_data, data, len);
645 * We must NUL-terminate this data, because Windows
646 * sscanf appears to require a NUL at the end of the
647 * string because it strlens it _first_. Sigh.
651 eol = get_line_end(data, len);
658 /* We can't rely on whether the %n incremented the sscanf return */
659 if (sscanf((char *)data, "HTTP/%i.%i %n",
660 &maj_ver, &min_ver, &status) < 2 || status == -1) {
661 plug_closing(p->plug, "Proxy error: HTTP response was absent",
662 PROXY_ERROR_GENERAL, 0);
667 /* remove the status line from the input buffer. */
668 bufchain_consume(&p->pending_input_data, eol);
669 if (data[status] != '2') {
673 while (eol > status &&
674 (data[eol-1] == '\r' || data[eol-1] == '\n'))
676 buf = dupprintf("Proxy error: %s", data+status);
677 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
690 /* get headers. we're done when we get a
691 * header of length 2, (ie. just "\r\n")
694 len = bufchain_size(&p->pending_input_data);
695 assert(len > 0); /* or we wouldn't be here */
696 data = snewn(len, char);
698 bufchain_fetch(&p->pending_input_data, data, len);
700 eol = get_line_end(datap, len);
707 bufchain_consume(&p->pending_input_data, eol);
710 eol = get_line_end(datap, len);
715 bufchain_consume(&p->pending_input_data, 2);
717 /* proxy activate will have dealt with
718 * whatever is left of the buffer */
728 plug_closing(p->plug, "Proxy error: unexpected proxy error",
729 PROXY_ERROR_UNEXPECTED, 0);
733 /* ----------------------------------------------------------------------
737 /* SOCKS version 4 */
738 int proxy_socks4_negotiate (Proxy_Socket p, int change)
740 if (p->state == PROXY_CHANGE_NEW) {
743 * version number (1 byte) = 4
744 * command code (1 byte)
747 * dest. port (2 bytes) [network order]
748 * dest. address (4 bytes)
749 * user ID (variable length, null terminated string)
752 int length, type, namelen;
753 char *command, addr[4], hostname[512];
756 type = sk_addrtype(p->remote_addr);
757 if (type == ADDRTYPE_IPV6) {
758 p->error = "Proxy error: SOCKS version 4 does not support IPv6";
760 } else if (type == ADDRTYPE_IPV4) {
762 sk_addrcopy(p->remote_addr, addr);
763 } else { /* type == ADDRTYPE_NAME */
764 assert(type == ADDRTYPE_NAME);
765 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
766 namelen = strlen(hostname) + 1; /* include the NUL */
767 addr[0] = addr[1] = addr[2] = 0;
771 username = conf_get_str(p->conf, CONF_proxy_username);
772 length = strlen(username) + namelen + 9;
773 command = snewn(length, char);
774 strcpy(command + 8, username);
776 command[0] = 4; /* version 4 */
777 command[1] = 1; /* CONNECT command */
780 command[2] = (char) (p->remote_port >> 8) & 0xff;
781 command[3] = (char) p->remote_port & 0xff;
784 memcpy(command + 4, addr, 4);
787 memcpy(command + 8 + strlen(username) + 1,
790 sk_write(p->sub_socket, command, length);
798 if (change == PROXY_CHANGE_CLOSING) {
799 /* if our proxy negotiation process involves closing and opening
800 * new sockets, then we would want to intercept this closing
801 * callback when we were expecting it. if we aren't anticipating
802 * a socket close, then some error must have occurred. we'll
803 * just pass those errors up to the backend.
805 return plug_closing(p->plug, p->closing_error_msg,
806 p->closing_error_code,
807 p->closing_calling_back);
810 if (change == PROXY_CHANGE_SENT) {
811 /* some (or all) of what we wrote to the proxy was sent.
812 * we don't do anything new, however, until we receive the
813 * proxy's response. we might want to set a timer so we can
814 * timeout the proxy negotiation after a while...
819 if (change == PROXY_CHANGE_ACCEPTING) {
820 /* we should _never_ see this, as we are using our socket to
821 * connect to a proxy, not accepting inbound connections.
822 * what should we do? close the socket with an appropriate
825 return plug_accepting(p->plug,
826 p->accepting_constructor, p->accepting_ctx);
829 if (change == PROXY_CHANGE_RECEIVE) {
830 /* we have received data from the underlying socket, which
831 * we'll need to parse, process, and respond to appropriately.
836 * version number (1 byte) = 4
837 * reply code (1 byte)
838 * 90 = request granted
839 * 91 = request rejected or failed
840 * 92 = request rejected due to lack of IDENTD on client
841 * 93 = request rejected due to difference in user ID
842 * (what we sent vs. what IDENTD said)
843 * dest. port (2 bytes)
844 * dest. address (4 bytes)
849 if (bufchain_size(&p->pending_input_data) < 8)
850 return 1; /* not got anything yet */
852 /* get the response */
853 bufchain_fetch(&p->pending_input_data, data, 8);
856 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
857 "unexpected reply code version",
858 PROXY_ERROR_GENERAL, 0);
866 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
867 PROXY_ERROR_GENERAL, 0);
870 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
871 PROXY_ERROR_GENERAL, 0);
875 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
876 PROXY_ERROR_GENERAL, 0);
882 bufchain_consume(&p->pending_input_data, 8);
886 /* proxy activate will have dealt with
887 * whatever is left of the buffer */
892 plug_closing(p->plug, "Proxy error: unexpected proxy error",
893 PROXY_ERROR_UNEXPECTED, 0);
897 /* SOCKS version 5 */
898 int proxy_socks5_negotiate (Proxy_Socket p, int change)
900 if (p->state == PROXY_CHANGE_NEW) {
903 * version number (1 byte) = 5
904 * number of available authentication methods (1 byte)
905 * available authentication methods (1 byte * previous value)
906 * authentication methods:
907 * 0x00 = no authentication
909 * 0x02 = username/password
914 char *username, *password;
917 command[0] = 5; /* version 5 */
918 username = conf_get_str(p->conf, CONF_proxy_username);
919 password = conf_get_str(p->conf, CONF_proxy_password);
920 if (username[0] || password[0]) {
921 command[2] = 0x00; /* no authentication */
923 proxy_socks5_offerencryptedauth (command, &len);
924 command[len++] = 0x02; /* username/password */
925 command[1] = len - 2; /* Number of methods supported */
927 command[1] = 1; /* one methods supported: */
928 command[2] = 0x00; /* no authentication */
932 sk_write(p->sub_socket, command, len);
938 if (change == PROXY_CHANGE_CLOSING) {
939 /* if our proxy negotiation process involves closing and opening
940 * new sockets, then we would want to intercept this closing
941 * callback when we were expecting it. if we aren't anticipating
942 * a socket close, then some error must have occurred. we'll
943 * just pass those errors up to the backend.
945 return plug_closing(p->plug, p->closing_error_msg,
946 p->closing_error_code,
947 p->closing_calling_back);
950 if (change == PROXY_CHANGE_SENT) {
951 /* some (or all) of what we wrote to the proxy was sent.
952 * we don't do anything new, however, until we receive the
953 * proxy's response. we might want to set a timer so we can
954 * timeout the proxy negotiation after a while...
959 if (change == PROXY_CHANGE_ACCEPTING) {
960 /* we should _never_ see this, as we are using our socket to
961 * connect to a proxy, not accepting inbound connections.
962 * what should we do? close the socket with an appropriate
965 return plug_accepting(p->plug,
966 p->accepting_constructor, p->accepting_ctx);
969 if (change == PROXY_CHANGE_RECEIVE) {
970 /* we have received data from the underlying socket, which
971 * we'll need to parse, process, and respond to appropriately.
977 * version number (1 byte) = 5
978 * authentication method (1 byte)
979 * authentication methods:
980 * 0x00 = no authentication
982 * 0x02 = username/password
984 * 0xff = no acceptable methods
988 if (bufchain_size(&p->pending_input_data) < 2)
989 return 1; /* not got anything yet */
991 /* get the response */
992 bufchain_fetch(&p->pending_input_data, data, 2);
995 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
996 PROXY_ERROR_GENERAL, 0);
1000 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
1001 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
1002 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
1003 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
1005 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
1006 PROXY_ERROR_GENERAL, 0);
1009 bufchain_consume(&p->pending_input_data, 2);
1012 if (p->state == 7) {
1014 /* password authentication reply format:
1015 * version number (1 bytes) = 1
1016 * reply code (1 byte)
1022 if (bufchain_size(&p->pending_input_data) < 2)
1023 return 1; /* not got anything yet */
1025 /* get the response */
1026 bufchain_fetch(&p->pending_input_data, data, 2);
1029 plug_closing(p->plug, "Proxy error: SOCKS password "
1030 "subnegotiation contained wrong version number",
1031 PROXY_ERROR_GENERAL, 0);
1037 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
1038 " password authentication",
1039 PROXY_ERROR_GENERAL, 0);
1043 bufchain_consume(&p->pending_input_data, 2);
1044 p->state = 2; /* now proceed as authenticated */
1047 if (p->state == 8) {
1049 ret = proxy_socks5_handlechap(p);
1050 if (ret) return ret;
1053 if (p->state == 2) {
1056 * version number (1 byte) = 5
1057 * command code (1 byte)
1061 * reserved (1 byte) = 0x00
1062 * address type (1 byte)
1064 * 3 = domainname (first byte has length, no terminating null)
1066 * dest. address (variable)
1067 * dest. port (2 bytes) [network order]
1074 type = sk_addrtype(p->remote_addr);
1075 if (type == ADDRTYPE_IPV4) {
1076 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1077 command[3] = 1; /* IPv4 */
1078 sk_addrcopy(p->remote_addr, command+4);
1079 } else if (type == ADDRTYPE_IPV6) {
1080 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1081 command[3] = 4; /* IPv6 */
1082 sk_addrcopy(p->remote_addr, command+4);
1084 assert(type == ADDRTYPE_NAME);
1086 sk_getaddr(p->remote_addr, command+5, 256);
1087 command[4] = strlen(command+5);
1088 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1091 command[0] = 5; /* version 5 */
1092 command[1] = 1; /* CONNECT command */
1096 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1097 command[len-1] = (char) p->remote_port & 0xff;
1099 sk_write(p->sub_socket, command, len);
1105 if (p->state == 3) {
1108 * version number (1 bytes) = 5
1109 * reply code (1 byte)
1111 * 1 = general SOCKS server failure
1112 * 2 = connection not allowed by ruleset
1113 * 3 = network unreachable
1114 * 4 = host unreachable
1115 * 5 = connection refused
1117 * 7 = command not supported
1118 * 8 = address type not supported
1119 * reserved (1 byte) = x00
1120 * address type (1 byte)
1122 * 3 = domainname (first byte has length, no terminating null)
1124 * server bound address (variable)
1125 * server bound port (2 bytes) [network order]
1130 /* First 5 bytes of packet are enough to tell its length. */
1131 if (bufchain_size(&p->pending_input_data) < 5)
1132 return 1; /* not got anything yet */
1134 /* get the response */
1135 bufchain_fetch(&p->pending_input_data, data, 5);
1138 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1139 PROXY_ERROR_GENERAL, 0);
1146 strcpy(buf, "Proxy error: ");
1149 case 1: strcat(buf, "General SOCKS server failure"); break;
1150 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1151 case 3: strcat(buf, "Network unreachable"); break;
1152 case 4: strcat(buf, "Host unreachable"); break;
1153 case 5: strcat(buf, "Connection refused"); break;
1154 case 6: strcat(buf, "TTL expired"); break;
1155 case 7: strcat(buf, "Command not supported"); break;
1156 case 8: strcat(buf, "Address type not supported"); break;
1157 default: sprintf(buf+strlen(buf),
1158 "Unrecognised SOCKS error code %d",
1162 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1168 * Eat the rest of the reply packet.
1170 len = 6; /* first 4 bytes, last 2 */
1172 case 1: len += 4; break; /* IPv4 address */
1173 case 4: len += 16; break;/* IPv6 address */
1174 case 3: len += (unsigned char)data[4]; break; /* domain name */
1176 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1177 "unrecognised address format",
1178 PROXY_ERROR_GENERAL, 0);
1181 if (bufchain_size(&p->pending_input_data) < len)
1182 return 1; /* not got whole reply yet */
1183 bufchain_consume(&p->pending_input_data, len);
1190 if (p->state == 4) {
1191 /* TODO: Handle GSSAPI authentication */
1192 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1193 PROXY_ERROR_GENERAL, 0);
1197 if (p->state == 5) {
1198 char *username = conf_get_str(p->conf, CONF_proxy_username);
1199 char *password = conf_get_str(p->conf, CONF_proxy_password);
1200 if (username[0] || password[0]) {
1201 char userpwbuf[255 + 255 + 3];
1203 ulen = strlen(username);
1204 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1205 plen = strlen(password);
1206 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1207 userpwbuf[0] = 1; /* version number of subnegotiation */
1208 userpwbuf[1] = ulen;
1209 memcpy(userpwbuf+2, username, ulen);
1210 userpwbuf[ulen+2] = plen;
1211 memcpy(userpwbuf+ulen+3, password, plen);
1212 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1215 plug_closing(p->plug, "Proxy error: Server chose "
1216 "username/password authentication but we "
1218 PROXY_ERROR_GENERAL, 0);
1222 if (p->state == 6) {
1224 ret = proxy_socks5_selectchap(p);
1225 if (ret) return ret;
1230 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1231 PROXY_ERROR_UNEXPECTED, 0);
1235 /* ----------------------------------------------------------------------
1236 * `Telnet' proxy type.
1238 * (This is for ad-hoc proxies where you connect to the proxy's
1239 * telnet port and send a command such as `connect host port'. The
1240 * command is configurable, since this proxy type is typically not
1241 * standardised or at all well-defined.)
1244 char *format_telnet_command(SockAddr addr, int port, Conf *conf)
1246 char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
1248 int retlen = 0, retsize = 0;
1250 #define ENSURE(n) do { \
1251 if (retsize < retlen + n) { \
1252 retsize = retlen + n + 512; \
1253 ret = sresize(ret, retsize, char); \
1257 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1258 * %%, %host, %port, %user, and %pass
1261 while (fmt[eo] != 0) {
1263 /* scan forward until we hit end-of-line,
1264 * or an escape character (\ or %) */
1265 while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
1268 /* if we hit eol, break out of our escaping loop */
1269 if (fmt[eo] == 0) break;
1271 /* if there was any unescaped text before the escape
1272 * character, send that now */
1275 memcpy(ret + retlen, fmt + so, eo - so);
1281 /* if the escape character was the last character of
1282 * the line, we'll just stop and send it. */
1283 if (fmt[eo] == 0) break;
1285 if (fmt[so] == '\\') {
1287 /* we recognize \\, \%, \r, \n, \t, \x??.
1288 * anything else, we just send unescaped (including the \).
1295 ret[retlen++] = '\\';
1301 ret[retlen++] = '%';
1307 ret[retlen++] = '\r';
1313 ret[retlen++] = '\n';
1319 ret[retlen++] = '\t';
1326 /* escaped hexadecimal value (ie. \xff) */
1327 unsigned char v = 0;
1332 if (fmt[eo] >= '0' && fmt[eo] <= '9')
1334 else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
1335 v += fmt[eo] - 'a' + 10;
1336 else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
1337 v += fmt[eo] - 'A' + 10;
1339 /* non hex character, so we abort and just
1340 * send the whole thing unescaped (including \x)
1343 ret[retlen++] = '\\';
1348 /* we only extract two hex characters */
1364 memcpy(ret+retlen, fmt + so, 2);
1371 /* % escape. we recognize %%, %host, %port, %user, %pass.
1372 * %proxyhost, %proxyport. Anything else we just send
1373 * unescaped (including the %).
1376 if (fmt[eo] == '%') {
1378 ret[retlen++] = '%';
1381 else if (strnicmp(fmt + eo, "host", 4) == 0) {
1384 sk_getaddr(addr, dest, lenof(dest));
1385 destlen = strlen(dest);
1387 memcpy(ret+retlen, dest, destlen);
1391 else if (strnicmp(fmt + eo, "port", 4) == 0) {
1392 char portstr[8], portlen;
1393 portlen = sprintf(portstr, "%i", port);
1395 memcpy(ret + retlen, portstr, portlen);
1399 else if (strnicmp(fmt + eo, "user", 4) == 0) {
1400 char *username = conf_get_str(conf, CONF_proxy_username);
1401 int userlen = strlen(username);
1403 memcpy(ret+retlen, username, userlen);
1407 else if (strnicmp(fmt + eo, "pass", 4) == 0) {
1408 char *password = conf_get_str(conf, CONF_proxy_password);
1409 int passlen = strlen(password);
1411 memcpy(ret+retlen, password, passlen);
1415 else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
1416 char *host = conf_get_str(conf, CONF_proxy_host);
1417 int phlen = strlen(host);
1419 memcpy(ret+retlen, host, phlen);
1423 else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
1424 int port = conf_get_int(conf, CONF_proxy_port);
1427 sprintf(pport, "%d", port);
1428 pplen = strlen(pport);
1430 memcpy(ret+retlen, pport, pplen);
1435 /* we don't escape this, so send the % now, and
1436 * don't advance eo, so that we'll consider the
1437 * text immediately following the % as unescaped.
1440 ret[retlen++] = '%';
1444 /* resume scanning for additional escapes after this one. */
1448 /* if there is any unescaped text at the end of the line, send it */
1451 memcpy(ret + retlen, fmt + so, eo - so);
1462 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1464 if (p->state == PROXY_CHANGE_NEW) {
1465 char *formatted_cmd;
1467 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1470 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1471 sfree(formatted_cmd);
1477 if (change == PROXY_CHANGE_CLOSING) {
1478 /* if our proxy negotiation process involves closing and opening
1479 * new sockets, then we would want to intercept this closing
1480 * callback when we were expecting it. if we aren't anticipating
1481 * a socket close, then some error must have occurred. we'll
1482 * just pass those errors up to the backend.
1484 return plug_closing(p->plug, p->closing_error_msg,
1485 p->closing_error_code,
1486 p->closing_calling_back);
1489 if (change == PROXY_CHANGE_SENT) {
1490 /* some (or all) of what we wrote to the proxy was sent.
1491 * we don't do anything new, however, until we receive the
1492 * proxy's response. we might want to set a timer so we can
1493 * timeout the proxy negotiation after a while...
1498 if (change == PROXY_CHANGE_ACCEPTING) {
1499 /* we should _never_ see this, as we are using our socket to
1500 * connect to a proxy, not accepting inbound connections.
1501 * what should we do? close the socket with an appropriate
1504 return plug_accepting(p->plug,
1505 p->accepting_constructor, p->accepting_ctx);
1508 if (change == PROXY_CHANGE_RECEIVE) {
1509 /* we have received data from the underlying socket, which
1510 * we'll need to parse, process, and respond to appropriately.
1515 /* proxy activate will have dealt with
1516 * whatever is left of the buffer */
1520 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1521 PROXY_ERROR_UNEXPECTED, 0);