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_frozen (Socket s, int is_frozen)
147 Proxy_Socket ps = (Proxy_Socket) s;
149 if (ps->state != PROXY_STATE_ACTIVE) {
150 ps->freeze = is_frozen;
154 /* handle any remaining buffered recv data first */
155 if (bufchain_size(&ps->pending_input_data) > 0) {
156 ps->freeze = is_frozen;
158 /* loop while we still have buffered data, and while we are
159 * unfrozen. the plug_receive call in the loop could result
160 * in a call back into this function refreezing the socket,
161 * so we have to check each time.
163 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
167 bufchain_prefix(&ps->pending_input_data, &data, &len);
168 if (len > lenof(databuf))
169 len = lenof(databuf);
170 memcpy(databuf, data, len);
171 bufchain_consume(&ps->pending_input_data, len);
172 plug_receive(ps->plug, 0, databuf, len);
175 /* if we're still frozen, we'll have to wait for another
176 * call from the backend to finish unbuffering the data.
178 if (ps->freeze) return;
181 sk_set_frozen(ps->sub_socket, is_frozen);
184 static const char * sk_proxy_socket_error (Socket s)
186 Proxy_Socket ps = (Proxy_Socket) s;
187 if (ps->error != NULL || ps->sub_socket == NULL) {
190 return sk_socket_error(ps->sub_socket);
193 /* basic proxy plug functions */
195 static void plug_proxy_log(Plug plug, int type, SockAddr addr, int port,
196 const char *error_msg, int error_code)
198 Proxy_Plug pp = (Proxy_Plug) plug;
199 Proxy_Socket ps = pp->proxy_socket;
201 plug_log(ps->plug, type, addr, port, error_msg, error_code);
204 static int plug_proxy_closing (Plug p, const char *error_msg,
205 int error_code, int calling_back)
207 Proxy_Plug pp = (Proxy_Plug) p;
208 Proxy_Socket ps = pp->proxy_socket;
210 if (ps->state != PROXY_STATE_ACTIVE) {
211 ps->closing_error_msg = error_msg;
212 ps->closing_error_code = error_code;
213 ps->closing_calling_back = calling_back;
214 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
216 return plug_closing(ps->plug, error_msg,
217 error_code, calling_back);
220 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
222 Proxy_Plug pp = (Proxy_Plug) p;
223 Proxy_Socket ps = pp->proxy_socket;
225 if (ps->state != PROXY_STATE_ACTIVE) {
226 /* we will lose the urgentness of this data, but since most,
227 * if not all, of this data will be consumed by the negotiation
228 * process, hopefully it won't affect the protocol above us
230 bufchain_add(&ps->pending_input_data, data, len);
231 ps->receive_urgent = urgent;
232 ps->receive_data = data;
233 ps->receive_len = len;
234 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
236 return plug_receive(ps->plug, urgent, data, len);
239 static void plug_proxy_sent (Plug p, int bufsize)
241 Proxy_Plug pp = (Proxy_Plug) p;
242 Proxy_Socket ps = pp->proxy_socket;
244 if (ps->state != PROXY_STATE_ACTIVE) {
245 ps->sent_bufsize = bufsize;
246 ps->negotiate(ps, PROXY_CHANGE_SENT);
249 plug_sent(ps->plug, bufsize);
252 static int plug_proxy_accepting(Plug p,
253 accept_fn_t constructor, accept_ctx_t ctx)
255 Proxy_Plug pp = (Proxy_Plug) p;
256 Proxy_Socket ps = pp->proxy_socket;
258 if (ps->state != PROXY_STATE_ACTIVE) {
259 ps->accepting_constructor = constructor;
260 ps->accepting_ctx = ctx;
261 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
263 return plug_accepting(ps->plug, constructor, ctx);
267 * This function can accept a NULL pointer as `addr', in which case
268 * it will only check the host name.
270 int proxy_for_destination (SockAddr addr, const char *hostname,
271 int port, Conf *conf)
275 int hostip_len, hostname_len;
276 const char *exclude_list;
279 * Special local connections such as Unix-domain sockets
280 * unconditionally cannot be proxied, even in proxy-localhost
281 * mode. There just isn't any way to ask any known proxy type for
284 if (addr && sk_address_is_special_local(addr))
285 return 0; /* do not proxy */
288 * Check the host name and IP against the hard-coded
289 * representations of `localhost'.
291 if (!conf_get_int(conf, CONF_even_proxy_localhost) &&
292 (sk_hostname_is_local(hostname) ||
293 (addr && sk_address_is_local(addr))))
294 return 0; /* do not proxy */
296 /* we want a string representation of the IP address for comparisons */
298 sk_getaddr(addr, hostip, 64);
299 hostip_len = strlen(hostip);
301 hostip_len = 0; /* placate gcc; shouldn't be required */
303 hostname_len = strlen(hostname);
305 exclude_list = conf_get_str(conf, CONF_proxy_exclude_list);
307 /* now parse the exclude list, and see if either our IP
308 * or hostname matches anything in it.
311 while (exclude_list[s]) {
312 while (exclude_list[s] &&
313 (isspace((unsigned char)exclude_list[s]) ||
314 exclude_list[s] == ',')) s++;
316 if (!exclude_list[s]) break;
320 while (exclude_list[e] &&
321 (isalnum((unsigned char)exclude_list[e]) ||
322 exclude_list[e] == '-' ||
323 exclude_list[e] == '.' ||
324 exclude_list[e] == '*')) e++;
326 if (exclude_list[s] == '*') {
327 /* wildcard at beginning of entry */
329 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
330 exclude_list + s + 1, e - s - 1) == 0) ||
331 strnicmp(hostname + hostname_len - (e - s - 1),
332 exclude_list + s + 1, e - s - 1) == 0)
333 return 0; /* IP/hostname range excluded. do not use proxy. */
335 } else if (exclude_list[e-1] == '*') {
336 /* wildcard at end of entry */
338 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
339 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
340 return 0; /* IP/hostname range excluded. do not use proxy. */
343 /* no wildcard at either end, so let's try an absolute
344 * match (ie. a specific IP)
347 if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
348 return 0; /* IP/hostname excluded. do not use proxy. */
349 if (strnicmp(hostname, exclude_list + s, e - s) == 0)
350 return 0; /* IP/hostname excluded. do not use proxy. */
355 /* Make sure we really have reached the next comma or end-of-string */
356 while (exclude_list[s] &&
357 !isspace((unsigned char)exclude_list[s]) &&
358 exclude_list[s] != ',') s++;
361 /* no matches in the exclude list, so use the proxy */
365 SockAddr name_lookup(const char *host, int port, char **canonicalname,
366 Conf *conf, int addressfamily, void *frontend,
370 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
371 do_proxy_dns(conf) &&
372 proxy_for_destination(NULL, host, port, conf)) {
375 logmsg = dupprintf("Leaving host lookup to proxy of \"%s\""
376 " (for %s)", host, reason);
377 logevent(frontend, logmsg);
381 *canonicalname = dupstr(host);
382 return sk_nonamelookup(host);
385 logmsg = dupprintf("Looking up host \"%s\"%s for %s", host,
386 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
387 addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
389 logevent(frontend, logmsg);
393 return sk_namelookup(host, canonicalname, addressfamily);
397 Socket new_connection(SockAddr addr, const char *hostname,
398 int port, int privport,
399 int oobinline, int nodelay, int keepalive,
400 Plug plug, Conf *conf)
402 static const struct socket_function_table socket_fn_table = {
410 sk_proxy_socket_error,
411 NULL, /* peer_info */
414 static const struct plug_function_table plug_fn_table = {
422 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
423 proxy_for_destination(addr, hostname, port, conf))
428 char *proxy_canonical_name;
432 if ((sret = platform_new_connection(addr, hostname, port, privport,
433 oobinline, nodelay, keepalive,
438 ret = snew(struct Socket_proxy_tag);
439 ret->fn = &socket_fn_table;
440 ret->conf = conf_copy(conf);
442 ret->remote_addr = addr; /* will need to be freed on close */
443 ret->remote_port = port;
446 ret->pending_flush = 0;
447 ret->pending_eof = 0;
450 bufchain_init(&ret->pending_input_data);
451 bufchain_init(&ret->pending_output_data);
452 bufchain_init(&ret->pending_oob_output_data);
454 ret->sub_socket = NULL;
455 ret->state = PROXY_STATE_NEW;
456 ret->negotiate = NULL;
458 type = conf_get_int(conf, CONF_proxy_type);
459 if (type == PROXY_HTTP) {
460 ret->negotiate = proxy_http_negotiate;
461 } else if (type == PROXY_SOCKS4) {
462 ret->negotiate = proxy_socks4_negotiate;
463 } else if (type == PROXY_SOCKS5) {
464 ret->negotiate = proxy_socks5_negotiate;
465 } else if (type == PROXY_TELNET) {
466 ret->negotiate = proxy_telnet_negotiate;
468 ret->error = "Proxy error: Unknown proxy method";
472 /* create the proxy plug to map calls from the actual
473 * socket into our proxy socket layer */
474 pplug = snew(struct Plug_proxy_tag);
475 pplug->fn = &plug_fn_table;
476 pplug->proxy_socket = ret;
479 proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
480 &proxy_canonical_name,
481 conf_get_int(conf, CONF_addressfamily));
482 if (sk_addr_error(proxy_addr) != NULL) {
483 ret->error = "Proxy error: Unable to resolve proxy host name";
485 sk_addr_free(proxy_addr);
488 sfree(proxy_canonical_name);
490 /* create the actual socket we will be using,
491 * connected to our proxy server and port.
493 ret->sub_socket = sk_new(proxy_addr,
494 conf_get_int(conf, CONF_proxy_port),
496 nodelay, keepalive, (Plug) pplug);
497 if (sk_socket_error(ret->sub_socket) != NULL)
500 /* start the proxy negotiation process... */
501 sk_set_frozen(ret->sub_socket, 0);
502 ret->negotiate(ret, PROXY_CHANGE_NEW);
507 /* no proxy, so just return the direct socket */
508 return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
511 Socket new_listener(const char *srcaddr, int port, Plug plug,
512 int local_host_only, Conf *conf, int addressfamily)
514 /* TODO: SOCKS (and potentially others) support inbound
515 * TODO: connections via the proxy. support them.
518 return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
521 /* ----------------------------------------------------------------------
522 * HTTP CONNECT proxy type.
525 static int get_line_end (char * data, int len)
531 if (data[off] == '\n') {
532 /* we have a newline */
535 /* is that the only thing on this line? */
536 if (off <= 2) return off;
538 /* if not, then there is the possibility that this header
539 * continues onto the next line, if it starts with a space
544 data[off+1] != ' ' &&
545 data[off+1] != '\t') return off;
547 /* the line does continue, so we have to keep going
548 * until we see an the header's "real" end of line.
559 int proxy_http_negotiate (Proxy_Socket p, int change)
561 if (p->state == PROXY_STATE_NEW) {
562 /* we are just beginning the proxy negotiate process,
563 * so we'll send off the initial bits of the request.
564 * for this proxy method, it's just a simple HTTP
567 char *buf, dest[512];
568 char *username, *password;
570 sk_getaddr(p->remote_addr, dest, lenof(dest));
572 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
573 dest, p->remote_port, dest, p->remote_port);
574 sk_write(p->sub_socket, buf, strlen(buf));
577 username = conf_get_str(p->conf, CONF_proxy_username);
578 password = conf_get_str(p->conf, CONF_proxy_password);
579 if (username[0] || password[0]) {
582 buf = dupprintf("%s:%s", username, password);
584 buf2 = snewn(len * 4 / 3 + 100, char);
585 sprintf(buf2, "Proxy-Authorization: Basic ");
586 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
587 base64_encode_atom((unsigned char *)(buf+i),
588 (len-i > 3 ? 3 : len-i), buf2+j);
589 strcpy(buf2+j, "\r\n");
590 sk_write(p->sub_socket, buf2, strlen(buf2));
595 sk_write(p->sub_socket, "\r\n", 2);
601 if (change == PROXY_CHANGE_CLOSING) {
602 /* if our proxy negotiation process involves closing and opening
603 * new sockets, then we would want to intercept this closing
604 * callback when we were expecting it. if we aren't anticipating
605 * a socket close, then some error must have occurred. we'll
606 * just pass those errors up to the backend.
608 return plug_closing(p->plug, p->closing_error_msg,
609 p->closing_error_code,
610 p->closing_calling_back);
613 if (change == PROXY_CHANGE_SENT) {
614 /* some (or all) of what we wrote to the proxy was sent.
615 * we don't do anything new, however, until we receive the
616 * proxy's response. we might want to set a timer so we can
617 * timeout the proxy negotiation after a while...
622 if (change == PROXY_CHANGE_ACCEPTING) {
623 /* we should _never_ see this, as we are using our socket to
624 * connect to a proxy, not accepting inbound connections.
625 * what should we do? close the socket with an appropriate
628 return plug_accepting(p->plug,
629 p->accepting_constructor, p->accepting_ctx);
632 if (change == PROXY_CHANGE_RECEIVE) {
633 /* we have received data from the underlying socket, which
634 * we'll need to parse, process, and respond to appropriately.
643 int min_ver, maj_ver, status;
645 /* get the status line */
646 len = bufchain_size(&p->pending_input_data);
647 assert(len > 0); /* or we wouldn't be here */
648 data = snewn(len+1, char);
649 bufchain_fetch(&p->pending_input_data, data, len);
651 * We must NUL-terminate this data, because Windows
652 * sscanf appears to require a NUL at the end of the
653 * string because it strlens it _first_. Sigh.
657 eol = get_line_end(data, len);
664 /* We can't rely on whether the %n incremented the sscanf return */
665 if (sscanf((char *)data, "HTTP/%i.%i %n",
666 &maj_ver, &min_ver, &status) < 2 || status == -1) {
667 plug_closing(p->plug, "Proxy error: HTTP response was absent",
668 PROXY_ERROR_GENERAL, 0);
673 /* remove the status line from the input buffer. */
674 bufchain_consume(&p->pending_input_data, eol);
675 if (data[status] != '2') {
679 while (eol > status &&
680 (data[eol-1] == '\r' || data[eol-1] == '\n'))
682 buf = dupprintf("Proxy error: %s", data+status);
683 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
696 /* get headers. we're done when we get a
697 * header of length 2, (ie. just "\r\n")
700 len = bufchain_size(&p->pending_input_data);
701 assert(len > 0); /* or we wouldn't be here */
702 data = snewn(len, char);
704 bufchain_fetch(&p->pending_input_data, data, len);
706 eol = get_line_end(datap, len);
713 bufchain_consume(&p->pending_input_data, eol);
716 eol = get_line_end(datap, len);
721 bufchain_consume(&p->pending_input_data, 2);
723 /* proxy activate will have dealt with
724 * whatever is left of the buffer */
734 plug_closing(p->plug, "Proxy error: unexpected proxy error",
735 PROXY_ERROR_UNEXPECTED, 0);
739 /* ----------------------------------------------------------------------
743 /* SOCKS version 4 */
744 int proxy_socks4_negotiate (Proxy_Socket p, int change)
746 if (p->state == PROXY_CHANGE_NEW) {
749 * version number (1 byte) = 4
750 * command code (1 byte)
753 * dest. port (2 bytes) [network order]
754 * dest. address (4 bytes)
755 * user ID (variable length, null terminated string)
758 int length, type, namelen;
759 char *command, addr[4], hostname[512];
762 type = sk_addrtype(p->remote_addr);
763 if (type == ADDRTYPE_IPV6) {
764 p->error = "Proxy error: SOCKS version 4 does not support IPv6";
766 } else if (type == ADDRTYPE_IPV4) {
768 sk_addrcopy(p->remote_addr, addr);
769 } else { /* type == ADDRTYPE_NAME */
770 assert(type == ADDRTYPE_NAME);
771 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
772 namelen = strlen(hostname) + 1; /* include the NUL */
773 addr[0] = addr[1] = addr[2] = 0;
777 username = conf_get_str(p->conf, CONF_proxy_username);
778 length = strlen(username) + namelen + 9;
779 command = snewn(length, char);
780 strcpy(command + 8, username);
782 command[0] = 4; /* version 4 */
783 command[1] = 1; /* CONNECT command */
786 command[2] = (char) (p->remote_port >> 8) & 0xff;
787 command[3] = (char) p->remote_port & 0xff;
790 memcpy(command + 4, addr, 4);
793 memcpy(command + 8 + strlen(username) + 1,
796 sk_write(p->sub_socket, command, length);
804 if (change == PROXY_CHANGE_CLOSING) {
805 /* if our proxy negotiation process involves closing and opening
806 * new sockets, then we would want to intercept this closing
807 * callback when we were expecting it. if we aren't anticipating
808 * a socket close, then some error must have occurred. we'll
809 * just pass those errors up to the backend.
811 return plug_closing(p->plug, p->closing_error_msg,
812 p->closing_error_code,
813 p->closing_calling_back);
816 if (change == PROXY_CHANGE_SENT) {
817 /* some (or all) of what we wrote to the proxy was sent.
818 * we don't do anything new, however, until we receive the
819 * proxy's response. we might want to set a timer so we can
820 * timeout the proxy negotiation after a while...
825 if (change == PROXY_CHANGE_ACCEPTING) {
826 /* we should _never_ see this, as we are using our socket to
827 * connect to a proxy, not accepting inbound connections.
828 * what should we do? close the socket with an appropriate
831 return plug_accepting(p->plug,
832 p->accepting_constructor, p->accepting_ctx);
835 if (change == PROXY_CHANGE_RECEIVE) {
836 /* we have received data from the underlying socket, which
837 * we'll need to parse, process, and respond to appropriately.
842 * version number (1 byte) = 4
843 * reply code (1 byte)
844 * 90 = request granted
845 * 91 = request rejected or failed
846 * 92 = request rejected due to lack of IDENTD on client
847 * 93 = request rejected due to difference in user ID
848 * (what we sent vs. what IDENTD said)
849 * dest. port (2 bytes)
850 * dest. address (4 bytes)
855 if (bufchain_size(&p->pending_input_data) < 8)
856 return 1; /* not got anything yet */
858 /* get the response */
859 bufchain_fetch(&p->pending_input_data, data, 8);
862 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
863 "unexpected reply code version",
864 PROXY_ERROR_GENERAL, 0);
872 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
873 PROXY_ERROR_GENERAL, 0);
876 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
877 PROXY_ERROR_GENERAL, 0);
881 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
882 PROXY_ERROR_GENERAL, 0);
888 bufchain_consume(&p->pending_input_data, 8);
892 /* proxy activate will have dealt with
893 * whatever is left of the buffer */
898 plug_closing(p->plug, "Proxy error: unexpected proxy error",
899 PROXY_ERROR_UNEXPECTED, 0);
903 /* SOCKS version 5 */
904 int proxy_socks5_negotiate (Proxy_Socket p, int change)
906 if (p->state == PROXY_CHANGE_NEW) {
909 * version number (1 byte) = 5
910 * number of available authentication methods (1 byte)
911 * available authentication methods (1 byte * previous value)
912 * authentication methods:
913 * 0x00 = no authentication
915 * 0x02 = username/password
920 char *username, *password;
923 command[0] = 5; /* version 5 */
924 username = conf_get_str(p->conf, CONF_proxy_username);
925 password = conf_get_str(p->conf, CONF_proxy_password);
926 if (username[0] || password[0]) {
927 command[2] = 0x00; /* no authentication */
929 proxy_socks5_offerencryptedauth (command, &len);
930 command[len++] = 0x02; /* username/password */
931 command[1] = len - 2; /* Number of methods supported */
933 command[1] = 1; /* one methods supported: */
934 command[2] = 0x00; /* no authentication */
938 sk_write(p->sub_socket, command, len);
944 if (change == PROXY_CHANGE_CLOSING) {
945 /* if our proxy negotiation process involves closing and opening
946 * new sockets, then we would want to intercept this closing
947 * callback when we were expecting it. if we aren't anticipating
948 * a socket close, then some error must have occurred. we'll
949 * just pass those errors up to the backend.
951 return plug_closing(p->plug, p->closing_error_msg,
952 p->closing_error_code,
953 p->closing_calling_back);
956 if (change == PROXY_CHANGE_SENT) {
957 /* some (or all) of what we wrote to the proxy was sent.
958 * we don't do anything new, however, until we receive the
959 * proxy's response. we might want to set a timer so we can
960 * timeout the proxy negotiation after a while...
965 if (change == PROXY_CHANGE_ACCEPTING) {
966 /* we should _never_ see this, as we are using our socket to
967 * connect to a proxy, not accepting inbound connections.
968 * what should we do? close the socket with an appropriate
971 return plug_accepting(p->plug,
972 p->accepting_constructor, p->accepting_ctx);
975 if (change == PROXY_CHANGE_RECEIVE) {
976 /* we have received data from the underlying socket, which
977 * we'll need to parse, process, and respond to appropriately.
983 * version number (1 byte) = 5
984 * authentication method (1 byte)
985 * authentication methods:
986 * 0x00 = no authentication
988 * 0x02 = username/password
990 * 0xff = no acceptable methods
994 if (bufchain_size(&p->pending_input_data) < 2)
995 return 1; /* not got anything yet */
997 /* get the response */
998 bufchain_fetch(&p->pending_input_data, data, 2);
1001 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
1002 PROXY_ERROR_GENERAL, 0);
1006 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
1007 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
1008 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
1009 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
1011 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
1012 PROXY_ERROR_GENERAL, 0);
1015 bufchain_consume(&p->pending_input_data, 2);
1018 if (p->state == 7) {
1020 /* password authentication reply format:
1021 * version number (1 bytes) = 1
1022 * reply code (1 byte)
1028 if (bufchain_size(&p->pending_input_data) < 2)
1029 return 1; /* not got anything yet */
1031 /* get the response */
1032 bufchain_fetch(&p->pending_input_data, data, 2);
1035 plug_closing(p->plug, "Proxy error: SOCKS password "
1036 "subnegotiation contained wrong version number",
1037 PROXY_ERROR_GENERAL, 0);
1043 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
1044 " password authentication",
1045 PROXY_ERROR_GENERAL, 0);
1049 bufchain_consume(&p->pending_input_data, 2);
1050 p->state = 2; /* now proceed as authenticated */
1053 if (p->state == 8) {
1055 ret = proxy_socks5_handlechap(p);
1056 if (ret) return ret;
1059 if (p->state == 2) {
1062 * version number (1 byte) = 5
1063 * command code (1 byte)
1067 * reserved (1 byte) = 0x00
1068 * address type (1 byte)
1070 * 3 = domainname (first byte has length, no terminating null)
1072 * dest. address (variable)
1073 * dest. port (2 bytes) [network order]
1080 type = sk_addrtype(p->remote_addr);
1081 if (type == ADDRTYPE_IPV4) {
1082 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1083 command[3] = 1; /* IPv4 */
1084 sk_addrcopy(p->remote_addr, command+4);
1085 } else if (type == ADDRTYPE_IPV6) {
1086 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1087 command[3] = 4; /* IPv6 */
1088 sk_addrcopy(p->remote_addr, command+4);
1090 assert(type == ADDRTYPE_NAME);
1092 sk_getaddr(p->remote_addr, command+5, 256);
1093 command[4] = strlen(command+5);
1094 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1097 command[0] = 5; /* version 5 */
1098 command[1] = 1; /* CONNECT command */
1102 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1103 command[len-1] = (char) p->remote_port & 0xff;
1105 sk_write(p->sub_socket, command, len);
1111 if (p->state == 3) {
1114 * version number (1 bytes) = 5
1115 * reply code (1 byte)
1117 * 1 = general SOCKS server failure
1118 * 2 = connection not allowed by ruleset
1119 * 3 = network unreachable
1120 * 4 = host unreachable
1121 * 5 = connection refused
1123 * 7 = command not supported
1124 * 8 = address type not supported
1125 * reserved (1 byte) = x00
1126 * address type (1 byte)
1128 * 3 = domainname (first byte has length, no terminating null)
1130 * server bound address (variable)
1131 * server bound port (2 bytes) [network order]
1136 /* First 5 bytes of packet are enough to tell its length. */
1137 if (bufchain_size(&p->pending_input_data) < 5)
1138 return 1; /* not got anything yet */
1140 /* get the response */
1141 bufchain_fetch(&p->pending_input_data, data, 5);
1144 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1145 PROXY_ERROR_GENERAL, 0);
1152 strcpy(buf, "Proxy error: ");
1155 case 1: strcat(buf, "General SOCKS server failure"); break;
1156 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1157 case 3: strcat(buf, "Network unreachable"); break;
1158 case 4: strcat(buf, "Host unreachable"); break;
1159 case 5: strcat(buf, "Connection refused"); break;
1160 case 6: strcat(buf, "TTL expired"); break;
1161 case 7: strcat(buf, "Command not supported"); break;
1162 case 8: strcat(buf, "Address type not supported"); break;
1163 default: sprintf(buf+strlen(buf),
1164 "Unrecognised SOCKS error code %d",
1168 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1174 * Eat the rest of the reply packet.
1176 len = 6; /* first 4 bytes, last 2 */
1178 case 1: len += 4; break; /* IPv4 address */
1179 case 4: len += 16; break;/* IPv6 address */
1180 case 3: len += (unsigned char)data[4]; break; /* domain name */
1182 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1183 "unrecognised address format",
1184 PROXY_ERROR_GENERAL, 0);
1187 if (bufchain_size(&p->pending_input_data) < len)
1188 return 1; /* not got whole reply yet */
1189 bufchain_consume(&p->pending_input_data, len);
1196 if (p->state == 4) {
1197 /* TODO: Handle GSSAPI authentication */
1198 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1199 PROXY_ERROR_GENERAL, 0);
1203 if (p->state == 5) {
1204 char *username = conf_get_str(p->conf, CONF_proxy_username);
1205 char *password = conf_get_str(p->conf, CONF_proxy_password);
1206 if (username[0] || password[0]) {
1207 char userpwbuf[255 + 255 + 3];
1209 ulen = strlen(username);
1210 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1211 plen = strlen(password);
1212 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1213 userpwbuf[0] = 1; /* version number of subnegotiation */
1214 userpwbuf[1] = ulen;
1215 memcpy(userpwbuf+2, username, ulen);
1216 userpwbuf[ulen+2] = plen;
1217 memcpy(userpwbuf+ulen+3, password, plen);
1218 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1221 plug_closing(p->plug, "Proxy error: Server chose "
1222 "username/password authentication but we "
1224 PROXY_ERROR_GENERAL, 0);
1228 if (p->state == 6) {
1230 ret = proxy_socks5_selectchap(p);
1231 if (ret) return ret;
1236 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1237 PROXY_ERROR_UNEXPECTED, 0);
1241 /* ----------------------------------------------------------------------
1242 * `Telnet' proxy type.
1244 * (This is for ad-hoc proxies where you connect to the proxy's
1245 * telnet port and send a command such as `connect host port'. The
1246 * command is configurable, since this proxy type is typically not
1247 * standardised or at all well-defined.)
1250 char *format_telnet_command(SockAddr addr, int port, Conf *conf)
1252 char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
1254 int retlen = 0, retsize = 0;
1256 #define ENSURE(n) do { \
1257 if (retsize < retlen + n) { \
1258 retsize = retlen + n + 512; \
1259 ret = sresize(ret, retsize, char); \
1263 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1264 * %%, %host, %port, %user, and %pass
1267 while (fmt[eo] != 0) {
1269 /* scan forward until we hit end-of-line,
1270 * or an escape character (\ or %) */
1271 while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
1274 /* if we hit eol, break out of our escaping loop */
1275 if (fmt[eo] == 0) break;
1277 /* if there was any unescaped text before the escape
1278 * character, send that now */
1281 memcpy(ret + retlen, fmt + so, eo - so);
1287 /* if the escape character was the last character of
1288 * the line, we'll just stop and send it. */
1289 if (fmt[eo] == 0) break;
1291 if (fmt[so] == '\\') {
1293 /* we recognize \\, \%, \r, \n, \t, \x??.
1294 * anything else, we just send unescaped (including the \).
1301 ret[retlen++] = '\\';
1307 ret[retlen++] = '%';
1313 ret[retlen++] = '\r';
1319 ret[retlen++] = '\n';
1325 ret[retlen++] = '\t';
1332 /* escaped hexadecimal value (ie. \xff) */
1333 unsigned char v = 0;
1338 if (fmt[eo] >= '0' && fmt[eo] <= '9')
1340 else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
1341 v += fmt[eo] - 'a' + 10;
1342 else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
1343 v += fmt[eo] - 'A' + 10;
1345 /* non hex character, so we abort and just
1346 * send the whole thing unescaped (including \x)
1349 ret[retlen++] = '\\';
1354 /* we only extract two hex characters */
1370 memcpy(ret+retlen, fmt + so, 2);
1377 /* % escape. we recognize %%, %host, %port, %user, %pass.
1378 * %proxyhost, %proxyport. Anything else we just send
1379 * unescaped (including the %).
1382 if (fmt[eo] == '%') {
1384 ret[retlen++] = '%';
1387 else if (strnicmp(fmt + eo, "host", 4) == 0) {
1390 sk_getaddr(addr, dest, lenof(dest));
1391 destlen = strlen(dest);
1393 memcpy(ret+retlen, dest, destlen);
1397 else if (strnicmp(fmt + eo, "port", 4) == 0) {
1398 char portstr[8], portlen;
1399 portlen = sprintf(portstr, "%i", port);
1401 memcpy(ret + retlen, portstr, portlen);
1405 else if (strnicmp(fmt + eo, "user", 4) == 0) {
1406 char *username = conf_get_str(conf, CONF_proxy_username);
1407 int userlen = strlen(username);
1409 memcpy(ret+retlen, username, userlen);
1413 else if (strnicmp(fmt + eo, "pass", 4) == 0) {
1414 char *password = conf_get_str(conf, CONF_proxy_password);
1415 int passlen = strlen(password);
1417 memcpy(ret+retlen, password, passlen);
1421 else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
1422 char *host = conf_get_str(conf, CONF_proxy_host);
1423 int phlen = strlen(host);
1425 memcpy(ret+retlen, host, phlen);
1429 else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
1430 int port = conf_get_int(conf, CONF_proxy_port);
1433 sprintf(pport, "%d", port);
1434 pplen = strlen(pport);
1436 memcpy(ret+retlen, pport, pplen);
1441 /* we don't escape this, so send the % now, and
1442 * don't advance eo, so that we'll consider the
1443 * text immediately following the % as unescaped.
1446 ret[retlen++] = '%';
1450 /* resume scanning for additional escapes after this one. */
1454 /* if there is any unescaped text at the end of the line, send it */
1457 memcpy(ret + retlen, fmt + so, eo - so);
1468 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1470 if (p->state == PROXY_CHANGE_NEW) {
1471 char *formatted_cmd;
1473 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1476 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1477 sfree(formatted_cmd);
1483 if (change == PROXY_CHANGE_CLOSING) {
1484 /* if our proxy negotiation process involves closing and opening
1485 * new sockets, then we would want to intercept this closing
1486 * callback when we were expecting it. if we aren't anticipating
1487 * a socket close, then some error must have occurred. we'll
1488 * just pass those errors up to the backend.
1490 return plug_closing(p->plug, p->closing_error_msg,
1491 p->closing_error_code,
1492 p->closing_calling_back);
1495 if (change == PROXY_CHANGE_SENT) {
1496 /* some (or all) of what we wrote to the proxy was sent.
1497 * we don't do anything new, however, until we receive the
1498 * proxy's response. we might want to set a timer so we can
1499 * timeout the proxy negotiation after a while...
1504 if (change == PROXY_CHANGE_ACCEPTING) {
1505 /* we should _never_ see this, as we are using our socket to
1506 * connect to a proxy, not accepting inbound connections.
1507 * what should we do? close the socket with an appropriate
1510 return plug_accepting(p->plug,
1511 p->accepting_constructor, p->accepting_ctx);
1514 if (change == PROXY_CHANGE_RECEIVE) {
1515 /* we have received data from the underlying socket, which
1516 * we'll need to parse, process, and respond to appropriately.
1521 /* proxy activate will have dealt with
1522 * whatever is left of the buffer */
1526 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1527 PROXY_ERROR_UNEXPECTED, 0);