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, char *hostname, int port,
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";
478 sfree(proxy_canonical_name);
480 /* create the actual socket we will be using,
481 * connected to our proxy server and port.
483 ret->sub_socket = sk_new(proxy_addr,
484 conf_get_int(conf, CONF_proxy_port),
486 nodelay, keepalive, (Plug) pplug);
487 if (sk_socket_error(ret->sub_socket) != NULL)
490 /* start the proxy negotiation process... */
491 sk_set_frozen(ret->sub_socket, 0);
492 ret->negotiate(ret, PROXY_CHANGE_NEW);
497 /* no proxy, so just return the direct socket */
498 return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
501 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
502 Conf *conf, int addressfamily)
504 /* TODO: SOCKS (and potentially others) support inbound
505 * TODO: connections via the proxy. support them.
508 return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
511 /* ----------------------------------------------------------------------
512 * HTTP CONNECT proxy type.
515 static int get_line_end (char * data, int len)
521 if (data[off] == '\n') {
522 /* we have a newline */
525 /* is that the only thing on this line? */
526 if (off <= 2) return off;
528 /* if not, then there is the possibility that this header
529 * continues onto the next line, if it starts with a space
534 data[off+1] != ' ' &&
535 data[off+1] != '\t') return off;
537 /* the line does continue, so we have to keep going
538 * until we see an the header's "real" end of line.
549 int proxy_http_negotiate (Proxy_Socket p, int change)
551 if (p->state == PROXY_STATE_NEW) {
552 /* we are just beginning the proxy negotiate process,
553 * so we'll send off the initial bits of the request.
554 * for this proxy method, it's just a simple HTTP
557 char *buf, dest[512];
558 char *username, *password;
560 sk_getaddr(p->remote_addr, dest, lenof(dest));
562 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
563 dest, p->remote_port, dest, p->remote_port);
564 sk_write(p->sub_socket, buf, strlen(buf));
567 username = conf_get_str(p->conf, CONF_proxy_username);
568 password = conf_get_str(p->conf, CONF_proxy_password);
569 if (username[0] || password[0]) {
572 buf = dupprintf("%s:%s", username, password);
574 buf2 = snewn(len * 4 / 3 + 100, char);
575 sprintf(buf2, "Proxy-Authorization: Basic ");
576 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
577 base64_encode_atom((unsigned char *)(buf+i),
578 (len-i > 3 ? 3 : len-i), buf2+j);
579 strcpy(buf2+j, "\r\n");
580 sk_write(p->sub_socket, buf2, strlen(buf2));
585 sk_write(p->sub_socket, "\r\n", 2);
591 if (change == PROXY_CHANGE_CLOSING) {
592 /* if our proxy negotiation process involves closing and opening
593 * new sockets, then we would want to intercept this closing
594 * callback when we were expecting it. if we aren't anticipating
595 * a socket close, then some error must have occurred. we'll
596 * just pass those errors up to the backend.
598 return plug_closing(p->plug, p->closing_error_msg,
599 p->closing_error_code,
600 p->closing_calling_back);
603 if (change == PROXY_CHANGE_SENT) {
604 /* some (or all) of what we wrote to the proxy was sent.
605 * we don't do anything new, however, until we receive the
606 * proxy's response. we might want to set a timer so we can
607 * timeout the proxy negotiation after a while...
612 if (change == PROXY_CHANGE_ACCEPTING) {
613 /* we should _never_ see this, as we are using our socket to
614 * connect to a proxy, not accepting inbound connections.
615 * what should we do? close the socket with an appropriate
618 return plug_accepting(p->plug, p->accepting_sock);
621 if (change == PROXY_CHANGE_RECEIVE) {
622 /* we have received data from the underlying socket, which
623 * we'll need to parse, process, and respond to appropriately.
632 int min_ver, maj_ver, status;
634 /* get the status line */
635 len = bufchain_size(&p->pending_input_data);
636 assert(len > 0); /* or we wouldn't be here */
637 data = snewn(len+1, char);
638 bufchain_fetch(&p->pending_input_data, data, len);
640 * We must NUL-terminate this data, because Windows
641 * sscanf appears to require a NUL at the end of the
642 * string because it strlens it _first_. Sigh.
646 eol = get_line_end(data, len);
653 /* We can't rely on whether the %n incremented the sscanf return */
654 if (sscanf((char *)data, "HTTP/%i.%i %n",
655 &maj_ver, &min_ver, &status) < 2 || status == -1) {
656 plug_closing(p->plug, "Proxy error: HTTP response was absent",
657 PROXY_ERROR_GENERAL, 0);
662 /* remove the status line from the input buffer. */
663 bufchain_consume(&p->pending_input_data, eol);
664 if (data[status] != '2') {
668 while (eol > status &&
669 (data[eol-1] == '\r' || data[eol-1] == '\n'))
671 buf = dupprintf("Proxy error: %s", data+status);
672 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
685 /* get headers. we're done when we get a
686 * header of length 2, (ie. just "\r\n")
689 len = bufchain_size(&p->pending_input_data);
690 assert(len > 0); /* or we wouldn't be here */
691 data = snewn(len, char);
693 bufchain_fetch(&p->pending_input_data, data, len);
695 eol = get_line_end(datap, len);
702 bufchain_consume(&p->pending_input_data, eol);
705 eol = get_line_end(datap, len);
710 bufchain_consume(&p->pending_input_data, 2);
712 /* proxy activate will have dealt with
713 * whatever is left of the buffer */
723 plug_closing(p->plug, "Proxy error: unexpected proxy error",
724 PROXY_ERROR_UNEXPECTED, 0);
728 /* ----------------------------------------------------------------------
732 /* SOCKS version 4 */
733 int proxy_socks4_negotiate (Proxy_Socket p, int change)
735 if (p->state == PROXY_CHANGE_NEW) {
738 * version number (1 byte) = 4
739 * command code (1 byte)
742 * dest. port (2 bytes) [network order]
743 * dest. address (4 bytes)
744 * user ID (variable length, null terminated string)
747 int length, type, namelen;
748 char *command, addr[4], hostname[512];
751 type = sk_addrtype(p->remote_addr);
752 if (type == ADDRTYPE_IPV6) {
753 p->error = "Proxy error: SOCKS version 4 does not support IPv6";
755 } else if (type == ADDRTYPE_IPV4) {
757 sk_addrcopy(p->remote_addr, addr);
758 } else { /* type == ADDRTYPE_NAME */
759 assert(type == ADDRTYPE_NAME);
760 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
761 namelen = strlen(hostname) + 1; /* include the NUL */
762 addr[0] = addr[1] = addr[2] = 0;
766 username = conf_get_str(p->conf, CONF_proxy_username);
767 length = strlen(username) + namelen + 9;
768 command = snewn(length, char);
769 strcpy(command + 8, username);
771 command[0] = 4; /* version 4 */
772 command[1] = 1; /* CONNECT command */
775 command[2] = (char) (p->remote_port >> 8) & 0xff;
776 command[3] = (char) p->remote_port & 0xff;
779 memcpy(command + 4, addr, 4);
782 memcpy(command + 8 + strlen(username) + 1,
785 sk_write(p->sub_socket, command, length);
793 if (change == PROXY_CHANGE_CLOSING) {
794 /* if our proxy negotiation process involves closing and opening
795 * new sockets, then we would want to intercept this closing
796 * callback when we were expecting it. if we aren't anticipating
797 * a socket close, then some error must have occurred. we'll
798 * just pass those errors up to the backend.
800 return plug_closing(p->plug, p->closing_error_msg,
801 p->closing_error_code,
802 p->closing_calling_back);
805 if (change == PROXY_CHANGE_SENT) {
806 /* some (or all) of what we wrote to the proxy was sent.
807 * we don't do anything new, however, until we receive the
808 * proxy's response. we might want to set a timer so we can
809 * timeout the proxy negotiation after a while...
814 if (change == PROXY_CHANGE_ACCEPTING) {
815 /* we should _never_ see this, as we are using our socket to
816 * connect to a proxy, not accepting inbound connections.
817 * what should we do? close the socket with an appropriate
820 return plug_accepting(p->plug, p->accepting_sock);
823 if (change == PROXY_CHANGE_RECEIVE) {
824 /* we have received data from the underlying socket, which
825 * we'll need to parse, process, and respond to appropriately.
830 * version number (1 byte) = 4
831 * reply code (1 byte)
832 * 90 = request granted
833 * 91 = request rejected or failed
834 * 92 = request rejected due to lack of IDENTD on client
835 * 93 = request rejected due to difference in user ID
836 * (what we sent vs. what IDENTD said)
837 * dest. port (2 bytes)
838 * dest. address (4 bytes)
843 if (bufchain_size(&p->pending_input_data) < 8)
844 return 1; /* not got anything yet */
846 /* get the response */
847 bufchain_fetch(&p->pending_input_data, data, 8);
850 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
851 "unexpected reply code version",
852 PROXY_ERROR_GENERAL, 0);
860 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
861 PROXY_ERROR_GENERAL, 0);
864 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
865 PROXY_ERROR_GENERAL, 0);
869 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
870 PROXY_ERROR_GENERAL, 0);
876 bufchain_consume(&p->pending_input_data, 8);
880 /* proxy activate will have dealt with
881 * whatever is left of the buffer */
886 plug_closing(p->plug, "Proxy error: unexpected proxy error",
887 PROXY_ERROR_UNEXPECTED, 0);
891 /* SOCKS version 5 */
892 int proxy_socks5_negotiate (Proxy_Socket p, int change)
894 if (p->state == PROXY_CHANGE_NEW) {
897 * version number (1 byte) = 5
898 * number of available authentication methods (1 byte)
899 * available authentication methods (1 byte * previous value)
900 * authentication methods:
901 * 0x00 = no authentication
903 * 0x02 = username/password
908 char *username, *password;
911 command[0] = 5; /* version 5 */
912 username = conf_get_str(p->conf, CONF_proxy_username);
913 password = conf_get_str(p->conf, CONF_proxy_password);
914 if (username[0] || password[0]) {
915 command[2] = 0x00; /* no authentication */
917 proxy_socks5_offerencryptedauth (command, &len);
918 command[len++] = 0x02; /* username/password */
919 command[1] = len - 2; /* Number of methods supported */
921 command[1] = 1; /* one methods supported: */
922 command[2] = 0x00; /* no authentication */
926 sk_write(p->sub_socket, command, len);
932 if (change == PROXY_CHANGE_CLOSING) {
933 /* if our proxy negotiation process involves closing and opening
934 * new sockets, then we would want to intercept this closing
935 * callback when we were expecting it. if we aren't anticipating
936 * a socket close, then some error must have occurred. we'll
937 * just pass those errors up to the backend.
939 return plug_closing(p->plug, p->closing_error_msg,
940 p->closing_error_code,
941 p->closing_calling_back);
944 if (change == PROXY_CHANGE_SENT) {
945 /* some (or all) of what we wrote to the proxy was sent.
946 * we don't do anything new, however, until we receive the
947 * proxy's response. we might want to set a timer so we can
948 * timeout the proxy negotiation after a while...
953 if (change == PROXY_CHANGE_ACCEPTING) {
954 /* we should _never_ see this, as we are using our socket to
955 * connect to a proxy, not accepting inbound connections.
956 * what should we do? close the socket with an appropriate
959 return plug_accepting(p->plug, p->accepting_sock);
962 if (change == PROXY_CHANGE_RECEIVE) {
963 /* we have received data from the underlying socket, which
964 * we'll need to parse, process, and respond to appropriately.
970 * version number (1 byte) = 5
971 * authentication method (1 byte)
972 * authentication methods:
973 * 0x00 = no authentication
975 * 0x02 = username/password
977 * 0xff = no acceptable methods
981 if (bufchain_size(&p->pending_input_data) < 2)
982 return 1; /* not got anything yet */
984 /* get the response */
985 bufchain_fetch(&p->pending_input_data, data, 2);
988 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
989 PROXY_ERROR_GENERAL, 0);
993 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
994 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
995 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
996 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
998 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
999 PROXY_ERROR_GENERAL, 0);
1002 bufchain_consume(&p->pending_input_data, 2);
1005 if (p->state == 7) {
1007 /* password authentication reply format:
1008 * version number (1 bytes) = 1
1009 * reply code (1 byte)
1015 if (bufchain_size(&p->pending_input_data) < 2)
1016 return 1; /* not got anything yet */
1018 /* get the response */
1019 bufchain_fetch(&p->pending_input_data, data, 2);
1022 plug_closing(p->plug, "Proxy error: SOCKS password "
1023 "subnegotiation contained wrong version number",
1024 PROXY_ERROR_GENERAL, 0);
1030 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
1031 " password authentication",
1032 PROXY_ERROR_GENERAL, 0);
1036 bufchain_consume(&p->pending_input_data, 2);
1037 p->state = 2; /* now proceed as authenticated */
1040 if (p->state == 8) {
1042 ret = proxy_socks5_handlechap(p);
1043 if (ret) return ret;
1046 if (p->state == 2) {
1049 * version number (1 byte) = 5
1050 * command code (1 byte)
1054 * reserved (1 byte) = 0x00
1055 * address type (1 byte)
1057 * 3 = domainname (first byte has length, no terminating null)
1059 * dest. address (variable)
1060 * dest. port (2 bytes) [network order]
1067 type = sk_addrtype(p->remote_addr);
1068 if (type == ADDRTYPE_IPV4) {
1069 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1070 command[3] = 1; /* IPv4 */
1071 sk_addrcopy(p->remote_addr, command+4);
1072 } else if (type == ADDRTYPE_IPV6) {
1073 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1074 command[3] = 4; /* IPv6 */
1075 sk_addrcopy(p->remote_addr, command+4);
1077 assert(type == ADDRTYPE_NAME);
1079 sk_getaddr(p->remote_addr, command+5, 256);
1080 command[4] = strlen(command+5);
1081 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1084 command[0] = 5; /* version 5 */
1085 command[1] = 1; /* CONNECT command */
1089 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1090 command[len-1] = (char) p->remote_port & 0xff;
1092 sk_write(p->sub_socket, command, len);
1098 if (p->state == 3) {
1101 * version number (1 bytes) = 5
1102 * reply code (1 byte)
1104 * 1 = general SOCKS server failure
1105 * 2 = connection not allowed by ruleset
1106 * 3 = network unreachable
1107 * 4 = host unreachable
1108 * 5 = connection refused
1110 * 7 = command not supported
1111 * 8 = address type not supported
1112 * reserved (1 byte) = x00
1113 * address type (1 byte)
1115 * 3 = domainname (first byte has length, no terminating null)
1117 * server bound address (variable)
1118 * server bound port (2 bytes) [network order]
1123 /* First 5 bytes of packet are enough to tell its length. */
1124 if (bufchain_size(&p->pending_input_data) < 5)
1125 return 1; /* not got anything yet */
1127 /* get the response */
1128 bufchain_fetch(&p->pending_input_data, data, 5);
1131 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1132 PROXY_ERROR_GENERAL, 0);
1139 strcpy(buf, "Proxy error: ");
1142 case 1: strcat(buf, "General SOCKS server failure"); break;
1143 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1144 case 3: strcat(buf, "Network unreachable"); break;
1145 case 4: strcat(buf, "Host unreachable"); break;
1146 case 5: strcat(buf, "Connection refused"); break;
1147 case 6: strcat(buf, "TTL expired"); break;
1148 case 7: strcat(buf, "Command not supported"); break;
1149 case 8: strcat(buf, "Address type not supported"); break;
1150 default: sprintf(buf+strlen(buf),
1151 "Unrecognised SOCKS error code %d",
1155 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1161 * Eat the rest of the reply packet.
1163 len = 6; /* first 4 bytes, last 2 */
1165 case 1: len += 4; break; /* IPv4 address */
1166 case 4: len += 16; break;/* IPv6 address */
1167 case 3: len += (unsigned char)data[4]; break; /* domain name */
1169 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1170 "unrecognised address format",
1171 PROXY_ERROR_GENERAL, 0);
1174 if (bufchain_size(&p->pending_input_data) < len)
1175 return 1; /* not got whole reply yet */
1176 bufchain_consume(&p->pending_input_data, len);
1183 if (p->state == 4) {
1184 /* TODO: Handle GSSAPI authentication */
1185 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1186 PROXY_ERROR_GENERAL, 0);
1190 if (p->state == 5) {
1191 char *username = conf_get_str(p->conf, CONF_proxy_username);
1192 char *password = conf_get_str(p->conf, CONF_proxy_password);
1193 if (username[0] || password[0]) {
1194 char userpwbuf[255 + 255 + 3];
1196 ulen = strlen(username);
1197 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1198 plen = strlen(password);
1199 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1200 userpwbuf[0] = 1; /* version number of subnegotiation */
1201 userpwbuf[1] = ulen;
1202 memcpy(userpwbuf+2, username, ulen);
1203 userpwbuf[ulen+2] = plen;
1204 memcpy(userpwbuf+ulen+3, password, plen);
1205 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1208 plug_closing(p->plug, "Proxy error: Server chose "
1209 "username/password authentication but we "
1211 PROXY_ERROR_GENERAL, 0);
1215 if (p->state == 6) {
1217 ret = proxy_socks5_selectchap(p);
1218 if (ret) return ret;
1223 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1224 PROXY_ERROR_UNEXPECTED, 0);
1228 /* ----------------------------------------------------------------------
1229 * `Telnet' proxy type.
1231 * (This is for ad-hoc proxies where you connect to the proxy's
1232 * telnet port and send a command such as `connect host port'. The
1233 * command is configurable, since this proxy type is typically not
1234 * standardised or at all well-defined.)
1237 char *format_telnet_command(SockAddr addr, int port, Conf *conf)
1239 char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
1241 int retlen = 0, retsize = 0;
1243 #define ENSURE(n) do { \
1244 if (retsize < retlen + n) { \
1245 retsize = retlen + n + 512; \
1246 ret = sresize(ret, retsize, char); \
1250 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1251 * %%, %host, %port, %user, and %pass
1254 while (fmt[eo] != 0) {
1256 /* scan forward until we hit end-of-line,
1257 * or an escape character (\ or %) */
1258 while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
1261 /* if we hit eol, break out of our escaping loop */
1262 if (fmt[eo] == 0) break;
1264 /* if there was any unescaped text before the escape
1265 * character, send that now */
1268 memcpy(ret + retlen, fmt + so, eo - so);
1274 /* if the escape character was the last character of
1275 * the line, we'll just stop and send it. */
1276 if (fmt[eo] == 0) break;
1278 if (fmt[so] == '\\') {
1280 /* we recognize \\, \%, \r, \n, \t, \x??.
1281 * anything else, we just send unescaped (including the \).
1288 ret[retlen++] = '\\';
1294 ret[retlen++] = '%';
1300 ret[retlen++] = '\r';
1306 ret[retlen++] = '\n';
1312 ret[retlen++] = '\t';
1319 /* escaped hexadecimal value (ie. \xff) */
1320 unsigned char v = 0;
1325 if (fmt[eo] >= '0' && fmt[eo] <= '9')
1327 else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
1328 v += fmt[eo] - 'a' + 10;
1329 else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
1330 v += fmt[eo] - 'A' + 10;
1332 /* non hex character, so we abort and just
1333 * send the whole thing unescaped (including \x)
1336 ret[retlen++] = '\\';
1341 /* we only extract two hex characters */
1357 memcpy(ret+retlen, fmt + so, 2);
1364 /* % escape. we recognize %%, %host, %port, %user, %pass.
1365 * %proxyhost, %proxyport. Anything else we just send
1366 * unescaped (including the %).
1369 if (fmt[eo] == '%') {
1371 ret[retlen++] = '%';
1374 else if (strnicmp(fmt + eo, "host", 4) == 0) {
1377 sk_getaddr(addr, dest, lenof(dest));
1378 destlen = strlen(dest);
1380 memcpy(ret+retlen, dest, destlen);
1384 else if (strnicmp(fmt + eo, "port", 4) == 0) {
1385 char portstr[8], portlen;
1386 portlen = sprintf(portstr, "%i", port);
1388 memcpy(ret + retlen, portstr, portlen);
1392 else if (strnicmp(fmt + eo, "user", 4) == 0) {
1393 char *username = conf_get_str(conf, CONF_proxy_username);
1394 int userlen = strlen(username);
1396 memcpy(ret+retlen, username, userlen);
1400 else if (strnicmp(fmt + eo, "pass", 4) == 0) {
1401 char *password = conf_get_str(conf, CONF_proxy_password);
1402 int passlen = strlen(password);
1404 memcpy(ret+retlen, password, passlen);
1408 else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
1409 char *host = conf_get_str(conf, CONF_proxy_host);
1410 int phlen = strlen(host);
1412 memcpy(ret+retlen, host, phlen);
1416 else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
1417 int port = conf_get_int(conf, CONF_proxy_port);
1420 sprintf(pport, "%d", port);
1421 pplen = strlen(pport);
1423 memcpy(ret+retlen, pport, pplen);
1428 /* we don't escape this, so send the % now, and
1429 * don't advance eo, so that we'll consider the
1430 * text immediately following the % as unescaped.
1433 ret[retlen++] = '%';
1437 /* resume scanning for additional escapes after this one. */
1441 /* if there is any unescaped text at the end of the line, send it */
1444 memcpy(ret + retlen, fmt + so, eo - so);
1455 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1457 if (p->state == PROXY_CHANGE_NEW) {
1458 char *formatted_cmd;
1460 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1463 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1464 sfree(formatted_cmd);
1470 if (change == PROXY_CHANGE_CLOSING) {
1471 /* if our proxy negotiation process involves closing and opening
1472 * new sockets, then we would want to intercept this closing
1473 * callback when we were expecting it. if we aren't anticipating
1474 * a socket close, then some error must have occurred. we'll
1475 * just pass those errors up to the backend.
1477 return plug_closing(p->plug, p->closing_error_msg,
1478 p->closing_error_code,
1479 p->closing_calling_back);
1482 if (change == PROXY_CHANGE_SENT) {
1483 /* some (or all) of what we wrote to the proxy was sent.
1484 * we don't do anything new, however, until we receive the
1485 * proxy's response. we might want to set a timer so we can
1486 * timeout the proxy negotiation after a while...
1491 if (change == PROXY_CHANGE_ACCEPTING) {
1492 /* we should _never_ see this, as we are using our socket to
1493 * connect to a proxy, not accepting inbound connections.
1494 * what should we do? close the socket with an appropriate
1497 return plug_accepting(p->plug, p->accepting_sock);
1500 if (change == PROXY_CHANGE_RECEIVE) {
1501 /* we have received data from the underlying socket, which
1502 * we'll need to parse, process, and respond to appropriately.
1507 /* proxy activate will have dealt with
1508 * whatever is left of the buffer */
1512 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1513 PROXY_ERROR_UNEXPECTED, 0);