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, OSSocket sock)
266 Proxy_Plug pp = (Proxy_Plug) p;
267 Proxy_Socket ps = pp->proxy_socket;
269 if (ps->state != PROXY_STATE_ACTIVE) {
270 ps->accepting_sock = sock;
271 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
273 return plug_accepting(ps->plug, sock);
277 * This function can accept a NULL pointer as `addr', in which case
278 * it will only check the host name.
280 static int proxy_for_destination (SockAddr addr, const char *hostname,
281 int port, Conf *conf)
285 int hostip_len, hostname_len;
286 const char *exclude_list;
289 * Special local connections such as Unix-domain sockets
290 * unconditionally cannot be proxied, even in proxy-localhost
291 * mode. There just isn't any way to ask any known proxy type for
294 if (addr && sk_address_is_special_local(addr))
295 return 0; /* do not proxy */
298 * Check the host name and IP against the hard-coded
299 * representations of `localhost'.
301 if (!conf_get_int(conf, CONF_even_proxy_localhost) &&
302 (sk_hostname_is_local(hostname) ||
303 (addr && sk_address_is_local(addr))))
304 return 0; /* do not proxy */
306 /* we want a string representation of the IP address for comparisons */
308 sk_getaddr(addr, hostip, 64);
309 hostip_len = strlen(hostip);
311 hostip_len = 0; /* placate gcc; shouldn't be required */
313 hostname_len = strlen(hostname);
315 exclude_list = conf_get_str(conf, CONF_proxy_exclude_list);
317 /* now parse the exclude list, and see if either our IP
318 * or hostname matches anything in it.
321 while (exclude_list[s]) {
322 while (exclude_list[s] &&
323 (isspace((unsigned char)exclude_list[s]) ||
324 exclude_list[s] == ',')) s++;
326 if (!exclude_list[s]) break;
330 while (exclude_list[e] &&
331 (isalnum((unsigned char)exclude_list[e]) ||
332 exclude_list[e] == '-' ||
333 exclude_list[e] == '.' ||
334 exclude_list[e] == '*')) e++;
336 if (exclude_list[s] == '*') {
337 /* wildcard at beginning of entry */
339 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
340 exclude_list + s + 1, e - s - 1) == 0) ||
341 strnicmp(hostname + hostname_len - (e - s - 1),
342 exclude_list + s + 1, e - s - 1) == 0)
343 return 0; /* IP/hostname range excluded. do not use proxy. */
345 } else if (exclude_list[e-1] == '*') {
346 /* wildcard at end of entry */
348 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
349 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
350 return 0; /* IP/hostname range excluded. do not use proxy. */
353 /* no wildcard at either end, so let's try an absolute
354 * match (ie. a specific IP)
357 if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
358 return 0; /* IP/hostname excluded. do not use proxy. */
359 if (strnicmp(hostname, exclude_list + s, e - s) == 0)
360 return 0; /* IP/hostname excluded. do not use proxy. */
365 /* Make sure we really have reached the next comma or end-of-string */
366 while (exclude_list[s] &&
367 !isspace((unsigned char)exclude_list[s]) &&
368 exclude_list[s] != ',') s++;
371 /* no matches in the exclude list, so use the proxy */
375 SockAddr name_lookup(char *host, int port, char **canonicalname,
376 Conf *conf, int addressfamily)
378 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
379 do_proxy_dns(conf) &&
380 proxy_for_destination(NULL, host, port, conf)) {
381 *canonicalname = dupstr(host);
382 return sk_nonamelookup(host);
385 return sk_namelookup(host, canonicalname, addressfamily);
388 Socket new_connection(SockAddr addr, char *hostname,
389 int port, int privport,
390 int oobinline, int nodelay, int keepalive,
391 Plug plug, Conf *conf)
393 static const struct socket_function_table socket_fn_table = {
400 sk_proxy_set_private_ptr,
401 sk_proxy_get_private_ptr,
403 sk_proxy_socket_error
406 static const struct plug_function_table plug_fn_table = {
414 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
415 proxy_for_destination(addr, hostname, port, conf))
420 char *proxy_canonical_name;
424 if ((sret = platform_new_connection(addr, hostname, port, privport,
425 oobinline, nodelay, keepalive,
430 ret = snew(struct Socket_proxy_tag);
431 ret->fn = &socket_fn_table;
432 ret->conf = conf_copy(conf);
434 ret->remote_addr = addr; /* will need to be freed on close */
435 ret->remote_port = port;
438 ret->pending_flush = 0;
439 ret->pending_eof = 0;
442 bufchain_init(&ret->pending_input_data);
443 bufchain_init(&ret->pending_output_data);
444 bufchain_init(&ret->pending_oob_output_data);
446 ret->sub_socket = NULL;
447 ret->state = PROXY_STATE_NEW;
448 ret->negotiate = NULL;
450 type = conf_get_int(conf, CONF_proxy_type);
451 if (type == PROXY_HTTP) {
452 ret->negotiate = proxy_http_negotiate;
453 } else if (type == PROXY_SOCKS4) {
454 ret->negotiate = proxy_socks4_negotiate;
455 } else if (type == PROXY_SOCKS5) {
456 ret->negotiate = proxy_socks5_negotiate;
457 } else if (type == PROXY_TELNET) {
458 ret->negotiate = proxy_telnet_negotiate;
460 ret->error = "Proxy error: Unknown proxy method";
464 /* create the proxy plug to map calls from the actual
465 * socket into our proxy socket layer */
466 pplug = snew(struct Plug_proxy_tag);
467 pplug->fn = &plug_fn_table;
468 pplug->proxy_socket = ret;
471 proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
472 &proxy_canonical_name,
473 conf_get_int(conf, CONF_addressfamily));
474 if (sk_addr_error(proxy_addr) != NULL) {
475 ret->error = "Proxy error: Unable to resolve proxy host name";
477 sk_addr_free(proxy_addr);
480 sfree(proxy_canonical_name);
482 /* create the actual socket we will be using,
483 * connected to our proxy server and port.
485 ret->sub_socket = sk_new(proxy_addr,
486 conf_get_int(conf, CONF_proxy_port),
488 nodelay, keepalive, (Plug) pplug);
489 if (sk_socket_error(ret->sub_socket) != NULL)
492 /* start the proxy negotiation process... */
493 sk_set_frozen(ret->sub_socket, 0);
494 ret->negotiate(ret, PROXY_CHANGE_NEW);
499 /* no proxy, so just return the direct socket */
500 return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
503 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
504 Conf *conf, int addressfamily)
506 /* TODO: SOCKS (and potentially others) support inbound
507 * TODO: connections via the proxy. support them.
510 return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
513 /* ----------------------------------------------------------------------
514 * HTTP CONNECT proxy type.
517 static int get_line_end (char * data, int len)
523 if (data[off] == '\n') {
524 /* we have a newline */
527 /* is that the only thing on this line? */
528 if (off <= 2) return off;
530 /* if not, then there is the possibility that this header
531 * continues onto the next line, if it starts with a space
536 data[off+1] != ' ' &&
537 data[off+1] != '\t') return off;
539 /* the line does continue, so we have to keep going
540 * until we see an the header's "real" end of line.
551 int proxy_http_negotiate (Proxy_Socket p, int change)
553 if (p->state == PROXY_STATE_NEW) {
554 /* we are just beginning the proxy negotiate process,
555 * so we'll send off the initial bits of the request.
556 * for this proxy method, it's just a simple HTTP
559 char *buf, dest[512];
560 char *username, *password;
562 sk_getaddr(p->remote_addr, dest, lenof(dest));
564 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
565 dest, p->remote_port, dest, p->remote_port);
566 sk_write(p->sub_socket, buf, strlen(buf));
569 username = conf_get_str(p->conf, CONF_proxy_username);
570 password = conf_get_str(p->conf, CONF_proxy_password);
571 if (username[0] || password[0]) {
574 buf = dupprintf("%s:%s", username, password);
576 buf2 = snewn(len * 4 / 3 + 100, char);
577 sprintf(buf2, "Proxy-Authorization: Basic ");
578 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
579 base64_encode_atom((unsigned char *)(buf+i),
580 (len-i > 3 ? 3 : len-i), buf2+j);
581 strcpy(buf2+j, "\r\n");
582 sk_write(p->sub_socket, buf2, strlen(buf2));
587 sk_write(p->sub_socket, "\r\n", 2);
593 if (change == PROXY_CHANGE_CLOSING) {
594 /* if our proxy negotiation process involves closing and opening
595 * new sockets, then we would want to intercept this closing
596 * callback when we were expecting it. if we aren't anticipating
597 * a socket close, then some error must have occurred. we'll
598 * just pass those errors up to the backend.
600 return plug_closing(p->plug, p->closing_error_msg,
601 p->closing_error_code,
602 p->closing_calling_back);
605 if (change == PROXY_CHANGE_SENT) {
606 /* some (or all) of what we wrote to the proxy was sent.
607 * we don't do anything new, however, until we receive the
608 * proxy's response. we might want to set a timer so we can
609 * timeout the proxy negotiation after a while...
614 if (change == PROXY_CHANGE_ACCEPTING) {
615 /* we should _never_ see this, as we are using our socket to
616 * connect to a proxy, not accepting inbound connections.
617 * what should we do? close the socket with an appropriate
620 return plug_accepting(p->plug, p->accepting_sock);
623 if (change == PROXY_CHANGE_RECEIVE) {
624 /* we have received data from the underlying socket, which
625 * we'll need to parse, process, and respond to appropriately.
634 int min_ver, maj_ver, status;
636 /* get the status line */
637 len = bufchain_size(&p->pending_input_data);
638 assert(len > 0); /* or we wouldn't be here */
639 data = snewn(len+1, char);
640 bufchain_fetch(&p->pending_input_data, data, len);
642 * We must NUL-terminate this data, because Windows
643 * sscanf appears to require a NUL at the end of the
644 * string because it strlens it _first_. Sigh.
648 eol = get_line_end(data, len);
655 /* We can't rely on whether the %n incremented the sscanf return */
656 if (sscanf((char *)data, "HTTP/%i.%i %n",
657 &maj_ver, &min_ver, &status) < 2 || status == -1) {
658 plug_closing(p->plug, "Proxy error: HTTP response was absent",
659 PROXY_ERROR_GENERAL, 0);
664 /* remove the status line from the input buffer. */
665 bufchain_consume(&p->pending_input_data, eol);
666 if (data[status] != '2') {
670 while (eol > status &&
671 (data[eol-1] == '\r' || data[eol-1] == '\n'))
673 buf = dupprintf("Proxy error: %s", data+status);
674 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
687 /* get headers. we're done when we get a
688 * header of length 2, (ie. just "\r\n")
691 len = bufchain_size(&p->pending_input_data);
692 assert(len > 0); /* or we wouldn't be here */
693 data = snewn(len, char);
695 bufchain_fetch(&p->pending_input_data, data, len);
697 eol = get_line_end(datap, len);
704 bufchain_consume(&p->pending_input_data, eol);
707 eol = get_line_end(datap, len);
712 bufchain_consume(&p->pending_input_data, 2);
714 /* proxy activate will have dealt with
715 * whatever is left of the buffer */
725 plug_closing(p->plug, "Proxy error: unexpected proxy error",
726 PROXY_ERROR_UNEXPECTED, 0);
730 /* ----------------------------------------------------------------------
734 /* SOCKS version 4 */
735 int proxy_socks4_negotiate (Proxy_Socket p, int change)
737 if (p->state == PROXY_CHANGE_NEW) {
740 * version number (1 byte) = 4
741 * command code (1 byte)
744 * dest. port (2 bytes) [network order]
745 * dest. address (4 bytes)
746 * user ID (variable length, null terminated string)
749 int length, type, namelen;
750 char *command, addr[4], hostname[512];
753 type = sk_addrtype(p->remote_addr);
754 if (type == ADDRTYPE_IPV6) {
755 p->error = "Proxy error: SOCKS version 4 does not support IPv6";
757 } else if (type == ADDRTYPE_IPV4) {
759 sk_addrcopy(p->remote_addr, addr);
760 } else { /* type == ADDRTYPE_NAME */
761 assert(type == ADDRTYPE_NAME);
762 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
763 namelen = strlen(hostname) + 1; /* include the NUL */
764 addr[0] = addr[1] = addr[2] = 0;
768 username = conf_get_str(p->conf, CONF_proxy_username);
769 length = strlen(username) + namelen + 9;
770 command = snewn(length, char);
771 strcpy(command + 8, username);
773 command[0] = 4; /* version 4 */
774 command[1] = 1; /* CONNECT command */
777 command[2] = (char) (p->remote_port >> 8) & 0xff;
778 command[3] = (char) p->remote_port & 0xff;
781 memcpy(command + 4, addr, 4);
784 memcpy(command + 8 + strlen(username) + 1,
787 sk_write(p->sub_socket, command, length);
795 if (change == PROXY_CHANGE_CLOSING) {
796 /* if our proxy negotiation process involves closing and opening
797 * new sockets, then we would want to intercept this closing
798 * callback when we were expecting it. if we aren't anticipating
799 * a socket close, then some error must have occurred. we'll
800 * just pass those errors up to the backend.
802 return plug_closing(p->plug, p->closing_error_msg,
803 p->closing_error_code,
804 p->closing_calling_back);
807 if (change == PROXY_CHANGE_SENT) {
808 /* some (or all) of what we wrote to the proxy was sent.
809 * we don't do anything new, however, until we receive the
810 * proxy's response. we might want to set a timer so we can
811 * timeout the proxy negotiation after a while...
816 if (change == PROXY_CHANGE_ACCEPTING) {
817 /* we should _never_ see this, as we are using our socket to
818 * connect to a proxy, not accepting inbound connections.
819 * what should we do? close the socket with an appropriate
822 return plug_accepting(p->plug, p->accepting_sock);
825 if (change == PROXY_CHANGE_RECEIVE) {
826 /* we have received data from the underlying socket, which
827 * we'll need to parse, process, and respond to appropriately.
832 * version number (1 byte) = 4
833 * reply code (1 byte)
834 * 90 = request granted
835 * 91 = request rejected or failed
836 * 92 = request rejected due to lack of IDENTD on client
837 * 93 = request rejected due to difference in user ID
838 * (what we sent vs. what IDENTD said)
839 * dest. port (2 bytes)
840 * dest. address (4 bytes)
845 if (bufchain_size(&p->pending_input_data) < 8)
846 return 1; /* not got anything yet */
848 /* get the response */
849 bufchain_fetch(&p->pending_input_data, data, 8);
852 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
853 "unexpected reply code version",
854 PROXY_ERROR_GENERAL, 0);
862 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
863 PROXY_ERROR_GENERAL, 0);
866 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
867 PROXY_ERROR_GENERAL, 0);
871 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
872 PROXY_ERROR_GENERAL, 0);
878 bufchain_consume(&p->pending_input_data, 8);
882 /* proxy activate will have dealt with
883 * whatever is left of the buffer */
888 plug_closing(p->plug, "Proxy error: unexpected proxy error",
889 PROXY_ERROR_UNEXPECTED, 0);
893 /* SOCKS version 5 */
894 int proxy_socks5_negotiate (Proxy_Socket p, int change)
896 if (p->state == PROXY_CHANGE_NEW) {
899 * version number (1 byte) = 5
900 * number of available authentication methods (1 byte)
901 * available authentication methods (1 byte * previous value)
902 * authentication methods:
903 * 0x00 = no authentication
905 * 0x02 = username/password
910 char *username, *password;
913 command[0] = 5; /* version 5 */
914 username = conf_get_str(p->conf, CONF_proxy_username);
915 password = conf_get_str(p->conf, CONF_proxy_password);
916 if (username[0] || password[0]) {
917 command[2] = 0x00; /* no authentication */
919 proxy_socks5_offerencryptedauth (command, &len);
920 command[len++] = 0x02; /* username/password */
921 command[1] = len - 2; /* Number of methods supported */
923 command[1] = 1; /* one methods supported: */
924 command[2] = 0x00; /* no authentication */
928 sk_write(p->sub_socket, command, len);
934 if (change == PROXY_CHANGE_CLOSING) {
935 /* if our proxy negotiation process involves closing and opening
936 * new sockets, then we would want to intercept this closing
937 * callback when we were expecting it. if we aren't anticipating
938 * a socket close, then some error must have occurred. we'll
939 * just pass those errors up to the backend.
941 return plug_closing(p->plug, p->closing_error_msg,
942 p->closing_error_code,
943 p->closing_calling_back);
946 if (change == PROXY_CHANGE_SENT) {
947 /* some (or all) of what we wrote to the proxy was sent.
948 * we don't do anything new, however, until we receive the
949 * proxy's response. we might want to set a timer so we can
950 * timeout the proxy negotiation after a while...
955 if (change == PROXY_CHANGE_ACCEPTING) {
956 /* we should _never_ see this, as we are using our socket to
957 * connect to a proxy, not accepting inbound connections.
958 * what should we do? close the socket with an appropriate
961 return plug_accepting(p->plug, p->accepting_sock);
964 if (change == PROXY_CHANGE_RECEIVE) {
965 /* we have received data from the underlying socket, which
966 * we'll need to parse, process, and respond to appropriately.
972 * version number (1 byte) = 5
973 * authentication method (1 byte)
974 * authentication methods:
975 * 0x00 = no authentication
977 * 0x02 = username/password
979 * 0xff = no acceptable methods
983 if (bufchain_size(&p->pending_input_data) < 2)
984 return 1; /* not got anything yet */
986 /* get the response */
987 bufchain_fetch(&p->pending_input_data, data, 2);
990 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
991 PROXY_ERROR_GENERAL, 0);
995 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
996 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
997 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
998 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
1000 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
1001 PROXY_ERROR_GENERAL, 0);
1004 bufchain_consume(&p->pending_input_data, 2);
1007 if (p->state == 7) {
1009 /* password authentication reply format:
1010 * version number (1 bytes) = 1
1011 * reply code (1 byte)
1017 if (bufchain_size(&p->pending_input_data) < 2)
1018 return 1; /* not got anything yet */
1020 /* get the response */
1021 bufchain_fetch(&p->pending_input_data, data, 2);
1024 plug_closing(p->plug, "Proxy error: SOCKS password "
1025 "subnegotiation contained wrong version number",
1026 PROXY_ERROR_GENERAL, 0);
1032 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
1033 " password authentication",
1034 PROXY_ERROR_GENERAL, 0);
1038 bufchain_consume(&p->pending_input_data, 2);
1039 p->state = 2; /* now proceed as authenticated */
1042 if (p->state == 8) {
1044 ret = proxy_socks5_handlechap(p);
1045 if (ret) return ret;
1048 if (p->state == 2) {
1051 * version number (1 byte) = 5
1052 * command code (1 byte)
1056 * reserved (1 byte) = 0x00
1057 * address type (1 byte)
1059 * 3 = domainname (first byte has length, no terminating null)
1061 * dest. address (variable)
1062 * dest. port (2 bytes) [network order]
1069 type = sk_addrtype(p->remote_addr);
1070 if (type == ADDRTYPE_IPV4) {
1071 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1072 command[3] = 1; /* IPv4 */
1073 sk_addrcopy(p->remote_addr, command+4);
1074 } else if (type == ADDRTYPE_IPV6) {
1075 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1076 command[3] = 4; /* IPv6 */
1077 sk_addrcopy(p->remote_addr, command+4);
1079 assert(type == ADDRTYPE_NAME);
1081 sk_getaddr(p->remote_addr, command+5, 256);
1082 command[4] = strlen(command+5);
1083 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1086 command[0] = 5; /* version 5 */
1087 command[1] = 1; /* CONNECT command */
1091 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1092 command[len-1] = (char) p->remote_port & 0xff;
1094 sk_write(p->sub_socket, command, len);
1100 if (p->state == 3) {
1103 * version number (1 bytes) = 5
1104 * reply code (1 byte)
1106 * 1 = general SOCKS server failure
1107 * 2 = connection not allowed by ruleset
1108 * 3 = network unreachable
1109 * 4 = host unreachable
1110 * 5 = connection refused
1112 * 7 = command not supported
1113 * 8 = address type not supported
1114 * reserved (1 byte) = x00
1115 * address type (1 byte)
1117 * 3 = domainname (first byte has length, no terminating null)
1119 * server bound address (variable)
1120 * server bound port (2 bytes) [network order]
1125 /* First 5 bytes of packet are enough to tell its length. */
1126 if (bufchain_size(&p->pending_input_data) < 5)
1127 return 1; /* not got anything yet */
1129 /* get the response */
1130 bufchain_fetch(&p->pending_input_data, data, 5);
1133 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1134 PROXY_ERROR_GENERAL, 0);
1141 strcpy(buf, "Proxy error: ");
1144 case 1: strcat(buf, "General SOCKS server failure"); break;
1145 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1146 case 3: strcat(buf, "Network unreachable"); break;
1147 case 4: strcat(buf, "Host unreachable"); break;
1148 case 5: strcat(buf, "Connection refused"); break;
1149 case 6: strcat(buf, "TTL expired"); break;
1150 case 7: strcat(buf, "Command not supported"); break;
1151 case 8: strcat(buf, "Address type not supported"); break;
1152 default: sprintf(buf+strlen(buf),
1153 "Unrecognised SOCKS error code %d",
1157 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1163 * Eat the rest of the reply packet.
1165 len = 6; /* first 4 bytes, last 2 */
1167 case 1: len += 4; break; /* IPv4 address */
1168 case 4: len += 16; break;/* IPv6 address */
1169 case 3: len += (unsigned char)data[4]; break; /* domain name */
1171 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1172 "unrecognised address format",
1173 PROXY_ERROR_GENERAL, 0);
1176 if (bufchain_size(&p->pending_input_data) < len)
1177 return 1; /* not got whole reply yet */
1178 bufchain_consume(&p->pending_input_data, len);
1185 if (p->state == 4) {
1186 /* TODO: Handle GSSAPI authentication */
1187 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1188 PROXY_ERROR_GENERAL, 0);
1192 if (p->state == 5) {
1193 char *username = conf_get_str(p->conf, CONF_proxy_username);
1194 char *password = conf_get_str(p->conf, CONF_proxy_password);
1195 if (username[0] || password[0]) {
1196 char userpwbuf[255 + 255 + 3];
1198 ulen = strlen(username);
1199 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1200 plen = strlen(password);
1201 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1202 userpwbuf[0] = 1; /* version number of subnegotiation */
1203 userpwbuf[1] = ulen;
1204 memcpy(userpwbuf+2, username, ulen);
1205 userpwbuf[ulen+2] = plen;
1206 memcpy(userpwbuf+ulen+3, password, plen);
1207 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1210 plug_closing(p->plug, "Proxy error: Server chose "
1211 "username/password authentication but we "
1213 PROXY_ERROR_GENERAL, 0);
1217 if (p->state == 6) {
1219 ret = proxy_socks5_selectchap(p);
1220 if (ret) return ret;
1225 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1226 PROXY_ERROR_UNEXPECTED, 0);
1230 /* ----------------------------------------------------------------------
1231 * `Telnet' proxy type.
1233 * (This is for ad-hoc proxies where you connect to the proxy's
1234 * telnet port and send a command such as `connect host port'. The
1235 * command is configurable, since this proxy type is typically not
1236 * standardised or at all well-defined.)
1239 char *format_telnet_command(SockAddr addr, int port, Conf *conf)
1241 char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
1243 int retlen = 0, retsize = 0;
1245 #define ENSURE(n) do { \
1246 if (retsize < retlen + n) { \
1247 retsize = retlen + n + 512; \
1248 ret = sresize(ret, retsize, char); \
1252 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1253 * %%, %host, %port, %user, and %pass
1256 while (fmt[eo] != 0) {
1258 /* scan forward until we hit end-of-line,
1259 * or an escape character (\ or %) */
1260 while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
1263 /* if we hit eol, break out of our escaping loop */
1264 if (fmt[eo] == 0) break;
1266 /* if there was any unescaped text before the escape
1267 * character, send that now */
1270 memcpy(ret + retlen, fmt + so, eo - so);
1276 /* if the escape character was the last character of
1277 * the line, we'll just stop and send it. */
1278 if (fmt[eo] == 0) break;
1280 if (fmt[so] == '\\') {
1282 /* we recognize \\, \%, \r, \n, \t, \x??.
1283 * anything else, we just send unescaped (including the \).
1290 ret[retlen++] = '\\';
1296 ret[retlen++] = '%';
1302 ret[retlen++] = '\r';
1308 ret[retlen++] = '\n';
1314 ret[retlen++] = '\t';
1321 /* escaped hexadecimal value (ie. \xff) */
1322 unsigned char v = 0;
1327 if (fmt[eo] >= '0' && fmt[eo] <= '9')
1329 else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
1330 v += fmt[eo] - 'a' + 10;
1331 else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
1332 v += fmt[eo] - 'A' + 10;
1334 /* non hex character, so we abort and just
1335 * send the whole thing unescaped (including \x)
1338 ret[retlen++] = '\\';
1343 /* we only extract two hex characters */
1359 memcpy(ret+retlen, fmt + so, 2);
1366 /* % escape. we recognize %%, %host, %port, %user, %pass.
1367 * %proxyhost, %proxyport. Anything else we just send
1368 * unescaped (including the %).
1371 if (fmt[eo] == '%') {
1373 ret[retlen++] = '%';
1376 else if (strnicmp(fmt + eo, "host", 4) == 0) {
1379 sk_getaddr(addr, dest, lenof(dest));
1380 destlen = strlen(dest);
1382 memcpy(ret+retlen, dest, destlen);
1386 else if (strnicmp(fmt + eo, "port", 4) == 0) {
1387 char portstr[8], portlen;
1388 portlen = sprintf(portstr, "%i", port);
1390 memcpy(ret + retlen, portstr, portlen);
1394 else if (strnicmp(fmt + eo, "user", 4) == 0) {
1395 char *username = conf_get_str(conf, CONF_proxy_username);
1396 int userlen = strlen(username);
1398 memcpy(ret+retlen, username, userlen);
1402 else if (strnicmp(fmt + eo, "pass", 4) == 0) {
1403 char *password = conf_get_str(conf, CONF_proxy_password);
1404 int passlen = strlen(password);
1406 memcpy(ret+retlen, password, passlen);
1410 else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
1411 char *host = conf_get_str(conf, CONF_proxy_host);
1412 int phlen = strlen(host);
1414 memcpy(ret+retlen, host, phlen);
1418 else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
1419 int port = conf_get_int(conf, CONF_proxy_port);
1422 sprintf(pport, "%d", port);
1423 pplen = strlen(pport);
1425 memcpy(ret+retlen, pport, pplen);
1430 /* we don't escape this, so send the % now, and
1431 * don't advance eo, so that we'll consider the
1432 * text immediately following the % as unescaped.
1435 ret[retlen++] = '%';
1439 /* resume scanning for additional escapes after this one. */
1443 /* if there is any unescaped text at the end of the line, send it */
1446 memcpy(ret + retlen, fmt + so, eo - so);
1457 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1459 if (p->state == PROXY_CHANGE_NEW) {
1460 char *formatted_cmd;
1462 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1465 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1466 sfree(formatted_cmd);
1472 if (change == PROXY_CHANGE_CLOSING) {
1473 /* if our proxy negotiation process involves closing and opening
1474 * new sockets, then we would want to intercept this closing
1475 * callback when we were expecting it. if we aren't anticipating
1476 * a socket close, then some error must have occurred. we'll
1477 * just pass those errors up to the backend.
1479 return plug_closing(p->plug, p->closing_error_msg,
1480 p->closing_error_code,
1481 p->closing_calling_back);
1484 if (change == PROXY_CHANGE_SENT) {
1485 /* some (or all) of what we wrote to the proxy was sent.
1486 * we don't do anything new, however, until we receive the
1487 * proxy's response. we might want to set a timer so we can
1488 * timeout the proxy negotiation after a while...
1493 if (change == PROXY_CHANGE_ACCEPTING) {
1494 /* we should _never_ see this, as we are using our socket to
1495 * connect to a proxy, not accepting inbound connections.
1496 * what should we do? close the socket with an appropriate
1499 return plug_accepting(p->plug, p->accepting_sock);
1502 if (change == PROXY_CHANGE_RECEIVE) {
1503 /* we have received data from the underlying socket, which
1504 * we'll need to parse, process, and respond to appropriately.
1509 /* proxy activate will have dealt with
1510 * whatever is left of the buffer */
1514 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1515 PROXY_ERROR_UNEXPECTED, 0);