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 static char *dns_log_msg(const char *host, int addressfamily,
368 return dupprintf("Looking up host \"%s\"%s for %s", host,
369 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
370 addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
374 SockAddr name_lookup(const char *host, int port, char **canonicalname,
375 Conf *conf, int addressfamily, void *frontend,
379 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
380 do_proxy_dns(conf) &&
381 proxy_for_destination(NULL, host, port, conf)) {
384 logmsg = dupprintf("Leaving host lookup to proxy of \"%s\""
385 " (for %s)", host, reason);
386 logevent(frontend, logmsg);
390 *canonicalname = dupstr(host);
391 return sk_nonamelookup(host);
394 logmsg = dns_log_msg(host, addressfamily, reason);
395 logevent(frontend, logmsg);
399 return sk_namelookup(host, canonicalname, addressfamily);
403 Socket new_connection(SockAddr addr, const char *hostname,
404 int port, int privport,
405 int oobinline, int nodelay, int keepalive,
406 Plug plug, Conf *conf)
408 static const struct socket_function_table socket_fn_table = {
416 sk_proxy_socket_error,
417 NULL, /* peer_info */
420 static const struct plug_function_table plug_fn_table = {
428 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
429 proxy_for_destination(addr, hostname, port, conf))
434 char *proxy_canonical_name;
435 const char *proxy_type;
439 if ((sret = platform_new_connection(addr, hostname, port, privport,
440 oobinline, nodelay, keepalive,
445 ret = snew(struct Socket_proxy_tag);
446 ret->fn = &socket_fn_table;
447 ret->conf = conf_copy(conf);
449 ret->remote_addr = addr; /* will need to be freed on close */
450 ret->remote_port = port;
453 ret->pending_flush = 0;
454 ret->pending_eof = 0;
457 bufchain_init(&ret->pending_input_data);
458 bufchain_init(&ret->pending_output_data);
459 bufchain_init(&ret->pending_oob_output_data);
461 ret->sub_socket = NULL;
462 ret->state = PROXY_STATE_NEW;
463 ret->negotiate = NULL;
465 type = conf_get_int(conf, CONF_proxy_type);
466 if (type == PROXY_HTTP) {
467 ret->negotiate = proxy_http_negotiate;
469 } else if (type == PROXY_SOCKS4) {
470 ret->negotiate = proxy_socks4_negotiate;
471 proxy_type = "SOCKS 4";
472 } else if (type == PROXY_SOCKS5) {
473 ret->negotiate = proxy_socks5_negotiate;
474 proxy_type = "SOCKS 5";
475 } else if (type == PROXY_TELNET) {
476 ret->negotiate = proxy_telnet_negotiate;
477 proxy_type = "Telnet";
479 ret->error = "Proxy error: Unknown proxy method";
484 char *logmsg = dupprintf("Will use %s proxy at %s:%d to connect"
485 " to %s:%d", proxy_type,
486 conf_get_str(conf, CONF_proxy_host),
487 conf_get_int(conf, CONF_proxy_port),
489 plug_log(plug, 2, NULL, 0, logmsg, 0);
493 /* create the proxy plug to map calls from the actual
494 * socket into our proxy socket layer */
495 pplug = snew(struct Plug_proxy_tag);
496 pplug->fn = &plug_fn_table;
497 pplug->proxy_socket = ret;
500 char *logmsg = dns_log_msg(conf_get_str(conf, CONF_proxy_host),
501 conf_get_int(conf, CONF_addressfamily),
503 plug_log(plug, 2, NULL, 0, logmsg, 0);
508 proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
509 &proxy_canonical_name,
510 conf_get_int(conf, CONF_addressfamily));
511 if (sk_addr_error(proxy_addr) != NULL) {
512 ret->error = "Proxy error: Unable to resolve proxy host name";
514 sk_addr_free(proxy_addr);
517 sfree(proxy_canonical_name);
520 char addrbuf[256], *logmsg;
521 sk_getaddr(addr, addrbuf, lenof(addrbuf));
522 logmsg = dupprintf("Connecting to %s proxy at %s port %d",
524 conf_get_int(conf, CONF_proxy_port));
525 plug_log(plug, 2, NULL, 0, logmsg, 0);
529 /* create the actual socket we will be using,
530 * connected to our proxy server and port.
532 ret->sub_socket = sk_new(proxy_addr,
533 conf_get_int(conf, CONF_proxy_port),
535 nodelay, keepalive, (Plug) pplug);
536 if (sk_socket_error(ret->sub_socket) != NULL)
539 /* start the proxy negotiation process... */
540 sk_set_frozen(ret->sub_socket, 0);
541 ret->negotiate(ret, PROXY_CHANGE_NEW);
546 /* no proxy, so just return the direct socket */
547 return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
550 Socket new_listener(const char *srcaddr, int port, Plug plug,
551 int local_host_only, Conf *conf, int addressfamily)
553 /* TODO: SOCKS (and potentially others) support inbound
554 * TODO: connections via the proxy. support them.
557 return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
560 /* ----------------------------------------------------------------------
561 * HTTP CONNECT proxy type.
564 static int get_line_end (char * data, int len)
570 if (data[off] == '\n') {
571 /* we have a newline */
574 /* is that the only thing on this line? */
575 if (off <= 2) return off;
577 /* if not, then there is the possibility that this header
578 * continues onto the next line, if it starts with a space
583 data[off+1] != ' ' &&
584 data[off+1] != '\t') return off;
586 /* the line does continue, so we have to keep going
587 * until we see an the header's "real" end of line.
598 int proxy_http_negotiate (Proxy_Socket p, int change)
600 if (p->state == PROXY_STATE_NEW) {
601 /* we are just beginning the proxy negotiate process,
602 * so we'll send off the initial bits of the request.
603 * for this proxy method, it's just a simple HTTP
606 char *buf, dest[512];
607 char *username, *password;
609 sk_getaddr(p->remote_addr, dest, lenof(dest));
611 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
612 dest, p->remote_port, dest, p->remote_port);
613 sk_write(p->sub_socket, buf, strlen(buf));
616 username = conf_get_str(p->conf, CONF_proxy_username);
617 password = conf_get_str(p->conf, CONF_proxy_password);
618 if (username[0] || password[0]) {
621 buf = dupprintf("%s:%s", username, password);
623 buf2 = snewn(len * 4 / 3 + 100, char);
624 sprintf(buf2, "Proxy-Authorization: Basic ");
625 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
626 base64_encode_atom((unsigned char *)(buf+i),
627 (len-i > 3 ? 3 : len-i), buf2+j);
628 strcpy(buf2+j, "\r\n");
629 sk_write(p->sub_socket, buf2, strlen(buf2));
634 sk_write(p->sub_socket, "\r\n", 2);
640 if (change == PROXY_CHANGE_CLOSING) {
641 /* if our proxy negotiation process involves closing and opening
642 * new sockets, then we would want to intercept this closing
643 * callback when we were expecting it. if we aren't anticipating
644 * a socket close, then some error must have occurred. we'll
645 * just pass those errors up to the backend.
647 return plug_closing(p->plug, p->closing_error_msg,
648 p->closing_error_code,
649 p->closing_calling_back);
652 if (change == PROXY_CHANGE_SENT) {
653 /* some (or all) of what we wrote to the proxy was sent.
654 * we don't do anything new, however, until we receive the
655 * proxy's response. we might want to set a timer so we can
656 * timeout the proxy negotiation after a while...
661 if (change == PROXY_CHANGE_ACCEPTING) {
662 /* we should _never_ see this, as we are using our socket to
663 * connect to a proxy, not accepting inbound connections.
664 * what should we do? close the socket with an appropriate
667 return plug_accepting(p->plug,
668 p->accepting_constructor, p->accepting_ctx);
671 if (change == PROXY_CHANGE_RECEIVE) {
672 /* we have received data from the underlying socket, which
673 * we'll need to parse, process, and respond to appropriately.
682 int min_ver, maj_ver, status;
684 /* get the status line */
685 len = bufchain_size(&p->pending_input_data);
686 assert(len > 0); /* or we wouldn't be here */
687 data = snewn(len+1, char);
688 bufchain_fetch(&p->pending_input_data, data, len);
690 * We must NUL-terminate this data, because Windows
691 * sscanf appears to require a NUL at the end of the
692 * string because it strlens it _first_. Sigh.
696 eol = get_line_end(data, len);
703 /* We can't rely on whether the %n incremented the sscanf return */
704 if (sscanf((char *)data, "HTTP/%i.%i %n",
705 &maj_ver, &min_ver, &status) < 2 || status == -1) {
706 plug_closing(p->plug, "Proxy error: HTTP response was absent",
707 PROXY_ERROR_GENERAL, 0);
712 /* remove the status line from the input buffer. */
713 bufchain_consume(&p->pending_input_data, eol);
714 if (data[status] != '2') {
718 while (eol > status &&
719 (data[eol-1] == '\r' || data[eol-1] == '\n'))
721 buf = dupprintf("Proxy error: %s", data+status);
722 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
735 /* get headers. we're done when we get a
736 * header of length 2, (ie. just "\r\n")
739 len = bufchain_size(&p->pending_input_data);
740 assert(len > 0); /* or we wouldn't be here */
741 data = snewn(len, char);
743 bufchain_fetch(&p->pending_input_data, data, len);
745 eol = get_line_end(datap, len);
752 bufchain_consume(&p->pending_input_data, eol);
755 eol = get_line_end(datap, len);
760 bufchain_consume(&p->pending_input_data, 2);
762 /* proxy activate will have dealt with
763 * whatever is left of the buffer */
773 plug_closing(p->plug, "Proxy error: unexpected proxy error",
774 PROXY_ERROR_UNEXPECTED, 0);
778 /* ----------------------------------------------------------------------
782 /* SOCKS version 4 */
783 int proxy_socks4_negotiate (Proxy_Socket p, int change)
785 if (p->state == PROXY_CHANGE_NEW) {
788 * version number (1 byte) = 4
789 * command code (1 byte)
792 * dest. port (2 bytes) [network order]
793 * dest. address (4 bytes)
794 * user ID (variable length, null terminated string)
797 int length, type, namelen;
798 char *command, addr[4], hostname[512];
801 type = sk_addrtype(p->remote_addr);
802 if (type == ADDRTYPE_IPV6) {
803 p->error = "Proxy error: SOCKS version 4 does not support IPv6";
805 } else if (type == ADDRTYPE_IPV4) {
807 sk_addrcopy(p->remote_addr, addr);
808 } else { /* type == ADDRTYPE_NAME */
809 assert(type == ADDRTYPE_NAME);
810 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
811 namelen = strlen(hostname) + 1; /* include the NUL */
812 addr[0] = addr[1] = addr[2] = 0;
816 username = conf_get_str(p->conf, CONF_proxy_username);
817 length = strlen(username) + namelen + 9;
818 command = snewn(length, char);
819 strcpy(command + 8, username);
821 command[0] = 4; /* version 4 */
822 command[1] = 1; /* CONNECT command */
825 command[2] = (char) (p->remote_port >> 8) & 0xff;
826 command[3] = (char) p->remote_port & 0xff;
829 memcpy(command + 4, addr, 4);
832 memcpy(command + 8 + strlen(username) + 1,
835 sk_write(p->sub_socket, command, length);
843 if (change == PROXY_CHANGE_CLOSING) {
844 /* if our proxy negotiation process involves closing and opening
845 * new sockets, then we would want to intercept this closing
846 * callback when we were expecting it. if we aren't anticipating
847 * a socket close, then some error must have occurred. we'll
848 * just pass those errors up to the backend.
850 return plug_closing(p->plug, p->closing_error_msg,
851 p->closing_error_code,
852 p->closing_calling_back);
855 if (change == PROXY_CHANGE_SENT) {
856 /* some (or all) of what we wrote to the proxy was sent.
857 * we don't do anything new, however, until we receive the
858 * proxy's response. we might want to set a timer so we can
859 * timeout the proxy negotiation after a while...
864 if (change == PROXY_CHANGE_ACCEPTING) {
865 /* we should _never_ see this, as we are using our socket to
866 * connect to a proxy, not accepting inbound connections.
867 * what should we do? close the socket with an appropriate
870 return plug_accepting(p->plug,
871 p->accepting_constructor, p->accepting_ctx);
874 if (change == PROXY_CHANGE_RECEIVE) {
875 /* we have received data from the underlying socket, which
876 * we'll need to parse, process, and respond to appropriately.
881 * version number (1 byte) = 4
882 * reply code (1 byte)
883 * 90 = request granted
884 * 91 = request rejected or failed
885 * 92 = request rejected due to lack of IDENTD on client
886 * 93 = request rejected due to difference in user ID
887 * (what we sent vs. what IDENTD said)
888 * dest. port (2 bytes)
889 * dest. address (4 bytes)
894 if (bufchain_size(&p->pending_input_data) < 8)
895 return 1; /* not got anything yet */
897 /* get the response */
898 bufchain_fetch(&p->pending_input_data, data, 8);
901 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
902 "unexpected reply code version",
903 PROXY_ERROR_GENERAL, 0);
911 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
912 PROXY_ERROR_GENERAL, 0);
915 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
916 PROXY_ERROR_GENERAL, 0);
920 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
921 PROXY_ERROR_GENERAL, 0);
927 bufchain_consume(&p->pending_input_data, 8);
931 /* proxy activate will have dealt with
932 * whatever is left of the buffer */
937 plug_closing(p->plug, "Proxy error: unexpected proxy error",
938 PROXY_ERROR_UNEXPECTED, 0);
942 /* SOCKS version 5 */
943 int proxy_socks5_negotiate (Proxy_Socket p, int change)
945 if (p->state == PROXY_CHANGE_NEW) {
948 * version number (1 byte) = 5
949 * number of available authentication methods (1 byte)
950 * available authentication methods (1 byte * previous value)
951 * authentication methods:
952 * 0x00 = no authentication
954 * 0x02 = username/password
959 char *username, *password;
962 command[0] = 5; /* version 5 */
963 username = conf_get_str(p->conf, CONF_proxy_username);
964 password = conf_get_str(p->conf, CONF_proxy_password);
965 if (username[0] || password[0]) {
966 command[2] = 0x00; /* no authentication */
968 proxy_socks5_offerencryptedauth (command, &len);
969 command[len++] = 0x02; /* username/password */
970 command[1] = len - 2; /* Number of methods supported */
972 command[1] = 1; /* one methods supported: */
973 command[2] = 0x00; /* no authentication */
977 sk_write(p->sub_socket, command, len);
983 if (change == PROXY_CHANGE_CLOSING) {
984 /* if our proxy negotiation process involves closing and opening
985 * new sockets, then we would want to intercept this closing
986 * callback when we were expecting it. if we aren't anticipating
987 * a socket close, then some error must have occurred. we'll
988 * just pass those errors up to the backend.
990 return plug_closing(p->plug, p->closing_error_msg,
991 p->closing_error_code,
992 p->closing_calling_back);
995 if (change == PROXY_CHANGE_SENT) {
996 /* some (or all) of what we wrote to the proxy was sent.
997 * we don't do anything new, however, until we receive the
998 * proxy's response. we might want to set a timer so we can
999 * timeout the proxy negotiation after a while...
1004 if (change == PROXY_CHANGE_ACCEPTING) {
1005 /* we should _never_ see this, as we are using our socket to
1006 * connect to a proxy, not accepting inbound connections.
1007 * what should we do? close the socket with an appropriate
1010 return plug_accepting(p->plug,
1011 p->accepting_constructor, p->accepting_ctx);
1014 if (change == PROXY_CHANGE_RECEIVE) {
1015 /* we have received data from the underlying socket, which
1016 * we'll need to parse, process, and respond to appropriately.
1019 if (p->state == 1) {
1021 /* initial response:
1022 * version number (1 byte) = 5
1023 * authentication method (1 byte)
1024 * authentication methods:
1025 * 0x00 = no authentication
1027 * 0x02 = username/password
1029 * 0xff = no acceptable methods
1033 if (bufchain_size(&p->pending_input_data) < 2)
1034 return 1; /* not got anything yet */
1036 /* get the response */
1037 bufchain_fetch(&p->pending_input_data, data, 2);
1040 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
1041 PROXY_ERROR_GENERAL, 0);
1045 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
1046 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
1047 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
1048 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
1050 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
1051 PROXY_ERROR_GENERAL, 0);
1054 bufchain_consume(&p->pending_input_data, 2);
1057 if (p->state == 7) {
1059 /* password authentication reply format:
1060 * version number (1 bytes) = 1
1061 * reply code (1 byte)
1067 if (bufchain_size(&p->pending_input_data) < 2)
1068 return 1; /* not got anything yet */
1070 /* get the response */
1071 bufchain_fetch(&p->pending_input_data, data, 2);
1074 plug_closing(p->plug, "Proxy error: SOCKS password "
1075 "subnegotiation contained wrong version number",
1076 PROXY_ERROR_GENERAL, 0);
1082 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
1083 " password authentication",
1084 PROXY_ERROR_GENERAL, 0);
1088 bufchain_consume(&p->pending_input_data, 2);
1089 p->state = 2; /* now proceed as authenticated */
1092 if (p->state == 8) {
1094 ret = proxy_socks5_handlechap(p);
1095 if (ret) return ret;
1098 if (p->state == 2) {
1101 * version number (1 byte) = 5
1102 * command code (1 byte)
1106 * reserved (1 byte) = 0x00
1107 * address type (1 byte)
1109 * 3 = domainname (first byte has length, no terminating null)
1111 * dest. address (variable)
1112 * dest. port (2 bytes) [network order]
1119 type = sk_addrtype(p->remote_addr);
1120 if (type == ADDRTYPE_IPV4) {
1121 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1122 command[3] = 1; /* IPv4 */
1123 sk_addrcopy(p->remote_addr, command+4);
1124 } else if (type == ADDRTYPE_IPV6) {
1125 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1126 command[3] = 4; /* IPv6 */
1127 sk_addrcopy(p->remote_addr, command+4);
1129 assert(type == ADDRTYPE_NAME);
1131 sk_getaddr(p->remote_addr, command+5, 256);
1132 command[4] = strlen(command+5);
1133 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1136 command[0] = 5; /* version 5 */
1137 command[1] = 1; /* CONNECT command */
1141 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1142 command[len-1] = (char) p->remote_port & 0xff;
1144 sk_write(p->sub_socket, command, len);
1150 if (p->state == 3) {
1153 * version number (1 bytes) = 5
1154 * reply code (1 byte)
1156 * 1 = general SOCKS server failure
1157 * 2 = connection not allowed by ruleset
1158 * 3 = network unreachable
1159 * 4 = host unreachable
1160 * 5 = connection refused
1162 * 7 = command not supported
1163 * 8 = address type not supported
1164 * reserved (1 byte) = x00
1165 * address type (1 byte)
1167 * 3 = domainname (first byte has length, no terminating null)
1169 * server bound address (variable)
1170 * server bound port (2 bytes) [network order]
1175 /* First 5 bytes of packet are enough to tell its length. */
1176 if (bufchain_size(&p->pending_input_data) < 5)
1177 return 1; /* not got anything yet */
1179 /* get the response */
1180 bufchain_fetch(&p->pending_input_data, data, 5);
1183 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1184 PROXY_ERROR_GENERAL, 0);
1191 strcpy(buf, "Proxy error: ");
1194 case 1: strcat(buf, "General SOCKS server failure"); break;
1195 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1196 case 3: strcat(buf, "Network unreachable"); break;
1197 case 4: strcat(buf, "Host unreachable"); break;
1198 case 5: strcat(buf, "Connection refused"); break;
1199 case 6: strcat(buf, "TTL expired"); break;
1200 case 7: strcat(buf, "Command not supported"); break;
1201 case 8: strcat(buf, "Address type not supported"); break;
1202 default: sprintf(buf+strlen(buf),
1203 "Unrecognised SOCKS error code %d",
1207 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1213 * Eat the rest of the reply packet.
1215 len = 6; /* first 4 bytes, last 2 */
1217 case 1: len += 4; break; /* IPv4 address */
1218 case 4: len += 16; break;/* IPv6 address */
1219 case 3: len += (unsigned char)data[4]; break; /* domain name */
1221 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1222 "unrecognised address format",
1223 PROXY_ERROR_GENERAL, 0);
1226 if (bufchain_size(&p->pending_input_data) < len)
1227 return 1; /* not got whole reply yet */
1228 bufchain_consume(&p->pending_input_data, len);
1235 if (p->state == 4) {
1236 /* TODO: Handle GSSAPI authentication */
1237 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1238 PROXY_ERROR_GENERAL, 0);
1242 if (p->state == 5) {
1243 char *username = conf_get_str(p->conf, CONF_proxy_username);
1244 char *password = conf_get_str(p->conf, CONF_proxy_password);
1245 if (username[0] || password[0]) {
1246 char userpwbuf[255 + 255 + 3];
1248 ulen = strlen(username);
1249 if (ulen > 255) ulen = 255;
1250 if (ulen < 1) ulen = 1;
1251 plen = strlen(password);
1252 if (plen > 255) plen = 255;
1253 if (plen < 1) plen = 1;
1254 userpwbuf[0] = 1; /* version number of subnegotiation */
1255 userpwbuf[1] = ulen;
1256 memcpy(userpwbuf+2, username, ulen);
1257 userpwbuf[ulen+2] = plen;
1258 memcpy(userpwbuf+ulen+3, password, plen);
1259 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1262 plug_closing(p->plug, "Proxy error: Server chose "
1263 "username/password authentication but we "
1265 PROXY_ERROR_GENERAL, 0);
1269 if (p->state == 6) {
1271 ret = proxy_socks5_selectchap(p);
1272 if (ret) return ret;
1277 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1278 PROXY_ERROR_UNEXPECTED, 0);
1282 /* ----------------------------------------------------------------------
1283 * `Telnet' proxy type.
1285 * (This is for ad-hoc proxies where you connect to the proxy's
1286 * telnet port and send a command such as `connect host port'. The
1287 * command is configurable, since this proxy type is typically not
1288 * standardised or at all well-defined.)
1291 char *format_telnet_command(SockAddr addr, int port, Conf *conf)
1293 char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
1295 int retlen = 0, retsize = 0;
1297 #define ENSURE(n) do { \
1298 if (retsize < retlen + n) { \
1299 retsize = retlen + n + 512; \
1300 ret = sresize(ret, retsize, char); \
1304 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1305 * %%, %host, %port, %user, and %pass
1308 while (fmt[eo] != 0) {
1310 /* scan forward until we hit end-of-line,
1311 * or an escape character (\ or %) */
1312 while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
1315 /* if we hit eol, break out of our escaping loop */
1316 if (fmt[eo] == 0) break;
1318 /* if there was any unescaped text before the escape
1319 * character, send that now */
1322 memcpy(ret + retlen, fmt + so, eo - so);
1328 /* if the escape character was the last character of
1329 * the line, we'll just stop and send it. */
1330 if (fmt[eo] == 0) break;
1332 if (fmt[so] == '\\') {
1334 /* we recognize \\, \%, \r, \n, \t, \x??.
1335 * anything else, we just send unescaped (including the \).
1342 ret[retlen++] = '\\';
1348 ret[retlen++] = '%';
1354 ret[retlen++] = '\r';
1360 ret[retlen++] = '\n';
1366 ret[retlen++] = '\t';
1373 /* escaped hexadecimal value (ie. \xff) */
1374 unsigned char v = 0;
1379 if (fmt[eo] >= '0' && fmt[eo] <= '9')
1381 else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
1382 v += fmt[eo] - 'a' + 10;
1383 else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
1384 v += fmt[eo] - 'A' + 10;
1386 /* non hex character, so we abort and just
1387 * send the whole thing unescaped (including \x)
1390 ret[retlen++] = '\\';
1395 /* we only extract two hex characters */
1411 memcpy(ret+retlen, fmt + so, 2);
1418 /* % escape. we recognize %%, %host, %port, %user, %pass.
1419 * %proxyhost, %proxyport. Anything else we just send
1420 * unescaped (including the %).
1423 if (fmt[eo] == '%') {
1425 ret[retlen++] = '%';
1428 else if (strnicmp(fmt + eo, "host", 4) == 0) {
1431 sk_getaddr(addr, dest, lenof(dest));
1432 destlen = strlen(dest);
1434 memcpy(ret+retlen, dest, destlen);
1438 else if (strnicmp(fmt + eo, "port", 4) == 0) {
1439 char portstr[8], portlen;
1440 portlen = sprintf(portstr, "%i", port);
1442 memcpy(ret + retlen, portstr, portlen);
1446 else if (strnicmp(fmt + eo, "user", 4) == 0) {
1447 char *username = conf_get_str(conf, CONF_proxy_username);
1448 int userlen = strlen(username);
1450 memcpy(ret+retlen, username, userlen);
1454 else if (strnicmp(fmt + eo, "pass", 4) == 0) {
1455 char *password = conf_get_str(conf, CONF_proxy_password);
1456 int passlen = strlen(password);
1458 memcpy(ret+retlen, password, passlen);
1462 else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
1463 char *host = conf_get_str(conf, CONF_proxy_host);
1464 int phlen = strlen(host);
1466 memcpy(ret+retlen, host, phlen);
1470 else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
1471 int port = conf_get_int(conf, CONF_proxy_port);
1474 sprintf(pport, "%d", port);
1475 pplen = strlen(pport);
1477 memcpy(ret+retlen, pport, pplen);
1482 /* we don't escape this, so send the % now, and
1483 * don't advance eo, so that we'll consider the
1484 * text immediately following the % as unescaped.
1487 ret[retlen++] = '%';
1491 /* resume scanning for additional escapes after this one. */
1495 /* if there is any unescaped text at the end of the line, send it */
1498 memcpy(ret + retlen, fmt + so, eo - so);
1509 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1511 if (p->state == PROXY_CHANGE_NEW) {
1512 char *formatted_cmd;
1514 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1519 * Re-escape control chars in the command, for logging.
1521 char *reescaped = snewn(4*strlen(formatted_cmd) + 1, char);
1526 for (in = formatted_cmd, out = reescaped; *in; in++) {
1528 *out++ = '\\'; *out++ = 'n';
1529 } else if (*in == '\r') {
1530 *out++ = '\\'; *out++ = 'r';
1531 } else if (*in == '\t') {
1532 *out++ = '\\'; *out++ = 't';
1533 } else if (*in == '\\') {
1534 *out++ = '\\'; *out++ = '\\';
1535 } else if ((unsigned)(((unsigned char)*in) - 0x20) <
1539 out += sprintf(out, "\\x%02X", (unsigned)*in & 0xFF);
1544 logmsg = dupprintf("Sending Telnet proxy command: %s", reescaped);
1545 plug_log(p->plug, 2, NULL, 0, logmsg, 0);
1550 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1551 sfree(formatted_cmd);
1557 if (change == PROXY_CHANGE_CLOSING) {
1558 /* if our proxy negotiation process involves closing and opening
1559 * new sockets, then we would want to intercept this closing
1560 * callback when we were expecting it. if we aren't anticipating
1561 * a socket close, then some error must have occurred. we'll
1562 * just pass those errors up to the backend.
1564 return plug_closing(p->plug, p->closing_error_msg,
1565 p->closing_error_code,
1566 p->closing_calling_back);
1569 if (change == PROXY_CHANGE_SENT) {
1570 /* some (or all) of what we wrote to the proxy was sent.
1571 * we don't do anything new, however, until we receive the
1572 * proxy's response. we might want to set a timer so we can
1573 * timeout the proxy negotiation after a while...
1578 if (change == PROXY_CHANGE_ACCEPTING) {
1579 /* we should _never_ see this, as we are using our socket to
1580 * connect to a proxy, not accepting inbound connections.
1581 * what should we do? close the socket with an appropriate
1584 return plug_accepting(p->plug,
1585 p->accepting_constructor, p->accepting_ctx);
1588 if (change == PROXY_CHANGE_RECEIVE) {
1589 /* we have received data from the underlying socket, which
1590 * we'll need to parse, process, and respond to appropriately.
1595 /* proxy activate will have dealt with
1596 * whatever is left of the buffer */
1600 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1601 PROXY_ERROR_UNEXPECTED, 0);