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(char *host, int port, char **canonicalname,
366 Conf *conf, int addressfamily)
368 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
369 do_proxy_dns(conf) &&
370 proxy_for_destination(NULL, host, port, conf)) {
371 *canonicalname = dupstr(host);
372 return sk_nonamelookup(host);
375 return sk_namelookup(host, canonicalname, addressfamily);
378 Socket new_connection(SockAddr addr, char *hostname,
379 int port, int privport,
380 int oobinline, int nodelay, int keepalive,
381 Plug plug, Conf *conf)
383 static const struct socket_function_table socket_fn_table = {
391 sk_proxy_socket_error
394 static const struct plug_function_table plug_fn_table = {
402 if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
403 proxy_for_destination(addr, hostname, port, conf))
408 char *proxy_canonical_name;
412 if ((sret = platform_new_connection(addr, hostname, port, privport,
413 oobinline, nodelay, keepalive,
418 ret = snew(struct Socket_proxy_tag);
419 ret->fn = &socket_fn_table;
420 ret->conf = conf_copy(conf);
422 ret->remote_addr = addr; /* will need to be freed on close */
423 ret->remote_port = port;
426 ret->pending_flush = 0;
427 ret->pending_eof = 0;
430 bufchain_init(&ret->pending_input_data);
431 bufchain_init(&ret->pending_output_data);
432 bufchain_init(&ret->pending_oob_output_data);
434 ret->sub_socket = NULL;
435 ret->state = PROXY_STATE_NEW;
436 ret->negotiate = NULL;
438 type = conf_get_int(conf, CONF_proxy_type);
439 if (type == PROXY_HTTP) {
440 ret->negotiate = proxy_http_negotiate;
441 } else if (type == PROXY_SOCKS4) {
442 ret->negotiate = proxy_socks4_negotiate;
443 } else if (type == PROXY_SOCKS5) {
444 ret->negotiate = proxy_socks5_negotiate;
445 } else if (type == PROXY_TELNET) {
446 ret->negotiate = proxy_telnet_negotiate;
448 ret->error = "Proxy error: Unknown proxy method";
452 /* create the proxy plug to map calls from the actual
453 * socket into our proxy socket layer */
454 pplug = snew(struct Plug_proxy_tag);
455 pplug->fn = &plug_fn_table;
456 pplug->proxy_socket = ret;
459 proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
460 &proxy_canonical_name,
461 conf_get_int(conf, CONF_addressfamily));
462 if (sk_addr_error(proxy_addr) != NULL) {
463 ret->error = "Proxy error: Unable to resolve proxy host name";
465 sk_addr_free(proxy_addr);
468 sfree(proxy_canonical_name);
470 /* create the actual socket we will be using,
471 * connected to our proxy server and port.
473 ret->sub_socket = sk_new(proxy_addr,
474 conf_get_int(conf, CONF_proxy_port),
476 nodelay, keepalive, (Plug) pplug);
477 if (sk_socket_error(ret->sub_socket) != NULL)
480 /* start the proxy negotiation process... */
481 sk_set_frozen(ret->sub_socket, 0);
482 ret->negotiate(ret, PROXY_CHANGE_NEW);
487 /* no proxy, so just return the direct socket */
488 return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
491 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
492 Conf *conf, int addressfamily)
494 /* TODO: SOCKS (and potentially others) support inbound
495 * TODO: connections via the proxy. support them.
498 return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
501 /* ----------------------------------------------------------------------
502 * HTTP CONNECT proxy type.
505 static int get_line_end (char * data, int len)
511 if (data[off] == '\n') {
512 /* we have a newline */
515 /* is that the only thing on this line? */
516 if (off <= 2) return off;
518 /* if not, then there is the possibility that this header
519 * continues onto the next line, if it starts with a space
524 data[off+1] != ' ' &&
525 data[off+1] != '\t') return off;
527 /* the line does continue, so we have to keep going
528 * until we see an the header's "real" end of line.
539 int proxy_http_negotiate (Proxy_Socket p, int change)
541 if (p->state == PROXY_STATE_NEW) {
542 /* we are just beginning the proxy negotiate process,
543 * so we'll send off the initial bits of the request.
544 * for this proxy method, it's just a simple HTTP
547 char *buf, dest[512];
548 char *username, *password;
550 sk_getaddr(p->remote_addr, dest, lenof(dest));
552 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
553 dest, p->remote_port, dest, p->remote_port);
554 sk_write(p->sub_socket, buf, strlen(buf));
557 username = conf_get_str(p->conf, CONF_proxy_username);
558 password = conf_get_str(p->conf, CONF_proxy_password);
559 if (username[0] || password[0]) {
562 buf = dupprintf("%s:%s", username, password);
564 buf2 = snewn(len * 4 / 3 + 100, char);
565 sprintf(buf2, "Proxy-Authorization: Basic ");
566 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
567 base64_encode_atom((unsigned char *)(buf+i),
568 (len-i > 3 ? 3 : len-i), buf2+j);
569 strcpy(buf2+j, "\r\n");
570 sk_write(p->sub_socket, buf2, strlen(buf2));
575 sk_write(p->sub_socket, "\r\n", 2);
581 if (change == PROXY_CHANGE_CLOSING) {
582 /* if our proxy negotiation process involves closing and opening
583 * new sockets, then we would want to intercept this closing
584 * callback when we were expecting it. if we aren't anticipating
585 * a socket close, then some error must have occurred. we'll
586 * just pass those errors up to the backend.
588 return plug_closing(p->plug, p->closing_error_msg,
589 p->closing_error_code,
590 p->closing_calling_back);
593 if (change == PROXY_CHANGE_SENT) {
594 /* some (or all) of what we wrote to the proxy was sent.
595 * we don't do anything new, however, until we receive the
596 * proxy's response. we might want to set a timer so we can
597 * timeout the proxy negotiation after a while...
602 if (change == PROXY_CHANGE_ACCEPTING) {
603 /* we should _never_ see this, as we are using our socket to
604 * connect to a proxy, not accepting inbound connections.
605 * what should we do? close the socket with an appropriate
608 return plug_accepting(p->plug,
609 p->accepting_constructor, p->accepting_ctx);
612 if (change == PROXY_CHANGE_RECEIVE) {
613 /* we have received data from the underlying socket, which
614 * we'll need to parse, process, and respond to appropriately.
623 int min_ver, maj_ver, status;
625 /* get the status line */
626 len = bufchain_size(&p->pending_input_data);
627 assert(len > 0); /* or we wouldn't be here */
628 data = snewn(len+1, char);
629 bufchain_fetch(&p->pending_input_data, data, len);
631 * We must NUL-terminate this data, because Windows
632 * sscanf appears to require a NUL at the end of the
633 * string because it strlens it _first_. Sigh.
637 eol = get_line_end(data, len);
644 /* We can't rely on whether the %n incremented the sscanf return */
645 if (sscanf((char *)data, "HTTP/%i.%i %n",
646 &maj_ver, &min_ver, &status) < 2 || status == -1) {
647 plug_closing(p->plug, "Proxy error: HTTP response was absent",
648 PROXY_ERROR_GENERAL, 0);
653 /* remove the status line from the input buffer. */
654 bufchain_consume(&p->pending_input_data, eol);
655 if (data[status] != '2') {
659 while (eol > status &&
660 (data[eol-1] == '\r' || data[eol-1] == '\n'))
662 buf = dupprintf("Proxy error: %s", data+status);
663 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
676 /* get headers. we're done when we get a
677 * header of length 2, (ie. just "\r\n")
680 len = bufchain_size(&p->pending_input_data);
681 assert(len > 0); /* or we wouldn't be here */
682 data = snewn(len, char);
684 bufchain_fetch(&p->pending_input_data, data, len);
686 eol = get_line_end(datap, len);
693 bufchain_consume(&p->pending_input_data, eol);
696 eol = get_line_end(datap, len);
701 bufchain_consume(&p->pending_input_data, 2);
703 /* proxy activate will have dealt with
704 * whatever is left of the buffer */
714 plug_closing(p->plug, "Proxy error: unexpected proxy error",
715 PROXY_ERROR_UNEXPECTED, 0);
719 /* ----------------------------------------------------------------------
723 /* SOCKS version 4 */
724 int proxy_socks4_negotiate (Proxy_Socket p, int change)
726 if (p->state == PROXY_CHANGE_NEW) {
729 * version number (1 byte) = 4
730 * command code (1 byte)
733 * dest. port (2 bytes) [network order]
734 * dest. address (4 bytes)
735 * user ID (variable length, null terminated string)
738 int length, type, namelen;
739 char *command, addr[4], hostname[512];
742 type = sk_addrtype(p->remote_addr);
743 if (type == ADDRTYPE_IPV6) {
744 p->error = "Proxy error: SOCKS version 4 does not support IPv6";
746 } else if (type == ADDRTYPE_IPV4) {
748 sk_addrcopy(p->remote_addr, addr);
749 } else { /* type == ADDRTYPE_NAME */
750 assert(type == ADDRTYPE_NAME);
751 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
752 namelen = strlen(hostname) + 1; /* include the NUL */
753 addr[0] = addr[1] = addr[2] = 0;
757 username = conf_get_str(p->conf, CONF_proxy_username);
758 length = strlen(username) + namelen + 9;
759 command = snewn(length, char);
760 strcpy(command + 8, username);
762 command[0] = 4; /* version 4 */
763 command[1] = 1; /* CONNECT command */
766 command[2] = (char) (p->remote_port >> 8) & 0xff;
767 command[3] = (char) p->remote_port & 0xff;
770 memcpy(command + 4, addr, 4);
773 memcpy(command + 8 + strlen(username) + 1,
776 sk_write(p->sub_socket, command, length);
784 if (change == PROXY_CHANGE_CLOSING) {
785 /* if our proxy negotiation process involves closing and opening
786 * new sockets, then we would want to intercept this closing
787 * callback when we were expecting it. if we aren't anticipating
788 * a socket close, then some error must have occurred. we'll
789 * just pass those errors up to the backend.
791 return plug_closing(p->plug, p->closing_error_msg,
792 p->closing_error_code,
793 p->closing_calling_back);
796 if (change == PROXY_CHANGE_SENT) {
797 /* some (or all) of what we wrote to the proxy was sent.
798 * we don't do anything new, however, until we receive the
799 * proxy's response. we might want to set a timer so we can
800 * timeout the proxy negotiation after a while...
805 if (change == PROXY_CHANGE_ACCEPTING) {
806 /* we should _never_ see this, as we are using our socket to
807 * connect to a proxy, not accepting inbound connections.
808 * what should we do? close the socket with an appropriate
811 return plug_accepting(p->plug,
812 p->accepting_constructor, p->accepting_ctx);
815 if (change == PROXY_CHANGE_RECEIVE) {
816 /* we have received data from the underlying socket, which
817 * we'll need to parse, process, and respond to appropriately.
822 * version number (1 byte) = 4
823 * reply code (1 byte)
824 * 90 = request granted
825 * 91 = request rejected or failed
826 * 92 = request rejected due to lack of IDENTD on client
827 * 93 = request rejected due to difference in user ID
828 * (what we sent vs. what IDENTD said)
829 * dest. port (2 bytes)
830 * dest. address (4 bytes)
835 if (bufchain_size(&p->pending_input_data) < 8)
836 return 1; /* not got anything yet */
838 /* get the response */
839 bufchain_fetch(&p->pending_input_data, data, 8);
842 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
843 "unexpected reply code version",
844 PROXY_ERROR_GENERAL, 0);
852 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
853 PROXY_ERROR_GENERAL, 0);
856 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
857 PROXY_ERROR_GENERAL, 0);
861 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
862 PROXY_ERROR_GENERAL, 0);
868 bufchain_consume(&p->pending_input_data, 8);
872 /* proxy activate will have dealt with
873 * whatever is left of the buffer */
878 plug_closing(p->plug, "Proxy error: unexpected proxy error",
879 PROXY_ERROR_UNEXPECTED, 0);
883 /* SOCKS version 5 */
884 int proxy_socks5_negotiate (Proxy_Socket p, int change)
886 if (p->state == PROXY_CHANGE_NEW) {
889 * version number (1 byte) = 5
890 * number of available authentication methods (1 byte)
891 * available authentication methods (1 byte * previous value)
892 * authentication methods:
893 * 0x00 = no authentication
895 * 0x02 = username/password
900 char *username, *password;
903 command[0] = 5; /* version 5 */
904 username = conf_get_str(p->conf, CONF_proxy_username);
905 password = conf_get_str(p->conf, CONF_proxy_password);
906 if (username[0] || password[0]) {
907 command[2] = 0x00; /* no authentication */
909 proxy_socks5_offerencryptedauth (command, &len);
910 command[len++] = 0x02; /* username/password */
911 command[1] = len - 2; /* Number of methods supported */
913 command[1] = 1; /* one methods supported: */
914 command[2] = 0x00; /* no authentication */
918 sk_write(p->sub_socket, command, len);
924 if (change == PROXY_CHANGE_CLOSING) {
925 /* if our proxy negotiation process involves closing and opening
926 * new sockets, then we would want to intercept this closing
927 * callback when we were expecting it. if we aren't anticipating
928 * a socket close, then some error must have occurred. we'll
929 * just pass those errors up to the backend.
931 return plug_closing(p->plug, p->closing_error_msg,
932 p->closing_error_code,
933 p->closing_calling_back);
936 if (change == PROXY_CHANGE_SENT) {
937 /* some (or all) of what we wrote to the proxy was sent.
938 * we don't do anything new, however, until we receive the
939 * proxy's response. we might want to set a timer so we can
940 * timeout the proxy negotiation after a while...
945 if (change == PROXY_CHANGE_ACCEPTING) {
946 /* we should _never_ see this, as we are using our socket to
947 * connect to a proxy, not accepting inbound connections.
948 * what should we do? close the socket with an appropriate
951 return plug_accepting(p->plug,
952 p->accepting_constructor, p->accepting_ctx);
955 if (change == PROXY_CHANGE_RECEIVE) {
956 /* we have received data from the underlying socket, which
957 * we'll need to parse, process, and respond to appropriately.
963 * version number (1 byte) = 5
964 * authentication method (1 byte)
965 * authentication methods:
966 * 0x00 = no authentication
968 * 0x02 = username/password
970 * 0xff = no acceptable methods
974 if (bufchain_size(&p->pending_input_data) < 2)
975 return 1; /* not got anything yet */
977 /* get the response */
978 bufchain_fetch(&p->pending_input_data, data, 2);
981 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
982 PROXY_ERROR_GENERAL, 0);
986 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
987 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
988 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
989 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
991 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
992 PROXY_ERROR_GENERAL, 0);
995 bufchain_consume(&p->pending_input_data, 2);
1000 /* password authentication reply format:
1001 * version number (1 bytes) = 1
1002 * reply code (1 byte)
1008 if (bufchain_size(&p->pending_input_data) < 2)
1009 return 1; /* not got anything yet */
1011 /* get the response */
1012 bufchain_fetch(&p->pending_input_data, data, 2);
1015 plug_closing(p->plug, "Proxy error: SOCKS password "
1016 "subnegotiation contained wrong version number",
1017 PROXY_ERROR_GENERAL, 0);
1023 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
1024 " password authentication",
1025 PROXY_ERROR_GENERAL, 0);
1029 bufchain_consume(&p->pending_input_data, 2);
1030 p->state = 2; /* now proceed as authenticated */
1033 if (p->state == 8) {
1035 ret = proxy_socks5_handlechap(p);
1036 if (ret) return ret;
1039 if (p->state == 2) {
1042 * version number (1 byte) = 5
1043 * command code (1 byte)
1047 * reserved (1 byte) = 0x00
1048 * address type (1 byte)
1050 * 3 = domainname (first byte has length, no terminating null)
1052 * dest. address (variable)
1053 * dest. port (2 bytes) [network order]
1060 type = sk_addrtype(p->remote_addr);
1061 if (type == ADDRTYPE_IPV4) {
1062 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1063 command[3] = 1; /* IPv4 */
1064 sk_addrcopy(p->remote_addr, command+4);
1065 } else if (type == ADDRTYPE_IPV6) {
1066 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1067 command[3] = 4; /* IPv6 */
1068 sk_addrcopy(p->remote_addr, command+4);
1070 assert(type == ADDRTYPE_NAME);
1072 sk_getaddr(p->remote_addr, command+5, 256);
1073 command[4] = strlen(command+5);
1074 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1077 command[0] = 5; /* version 5 */
1078 command[1] = 1; /* CONNECT command */
1082 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1083 command[len-1] = (char) p->remote_port & 0xff;
1085 sk_write(p->sub_socket, command, len);
1091 if (p->state == 3) {
1094 * version number (1 bytes) = 5
1095 * reply code (1 byte)
1097 * 1 = general SOCKS server failure
1098 * 2 = connection not allowed by ruleset
1099 * 3 = network unreachable
1100 * 4 = host unreachable
1101 * 5 = connection refused
1103 * 7 = command not supported
1104 * 8 = address type not supported
1105 * reserved (1 byte) = x00
1106 * address type (1 byte)
1108 * 3 = domainname (first byte has length, no terminating null)
1110 * server bound address (variable)
1111 * server bound port (2 bytes) [network order]
1116 /* First 5 bytes of packet are enough to tell its length. */
1117 if (bufchain_size(&p->pending_input_data) < 5)
1118 return 1; /* not got anything yet */
1120 /* get the response */
1121 bufchain_fetch(&p->pending_input_data, data, 5);
1124 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1125 PROXY_ERROR_GENERAL, 0);
1132 strcpy(buf, "Proxy error: ");
1135 case 1: strcat(buf, "General SOCKS server failure"); break;
1136 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1137 case 3: strcat(buf, "Network unreachable"); break;
1138 case 4: strcat(buf, "Host unreachable"); break;
1139 case 5: strcat(buf, "Connection refused"); break;
1140 case 6: strcat(buf, "TTL expired"); break;
1141 case 7: strcat(buf, "Command not supported"); break;
1142 case 8: strcat(buf, "Address type not supported"); break;
1143 default: sprintf(buf+strlen(buf),
1144 "Unrecognised SOCKS error code %d",
1148 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1154 * Eat the rest of the reply packet.
1156 len = 6; /* first 4 bytes, last 2 */
1158 case 1: len += 4; break; /* IPv4 address */
1159 case 4: len += 16; break;/* IPv6 address */
1160 case 3: len += (unsigned char)data[4]; break; /* domain name */
1162 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1163 "unrecognised address format",
1164 PROXY_ERROR_GENERAL, 0);
1167 if (bufchain_size(&p->pending_input_data) < len)
1168 return 1; /* not got whole reply yet */
1169 bufchain_consume(&p->pending_input_data, len);
1176 if (p->state == 4) {
1177 /* TODO: Handle GSSAPI authentication */
1178 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1179 PROXY_ERROR_GENERAL, 0);
1183 if (p->state == 5) {
1184 char *username = conf_get_str(p->conf, CONF_proxy_username);
1185 char *password = conf_get_str(p->conf, CONF_proxy_password);
1186 if (username[0] || password[0]) {
1187 char userpwbuf[255 + 255 + 3];
1189 ulen = strlen(username);
1190 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1191 plen = strlen(password);
1192 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1193 userpwbuf[0] = 1; /* version number of subnegotiation */
1194 userpwbuf[1] = ulen;
1195 memcpy(userpwbuf+2, username, ulen);
1196 userpwbuf[ulen+2] = plen;
1197 memcpy(userpwbuf+ulen+3, password, plen);
1198 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1201 plug_closing(p->plug, "Proxy error: Server chose "
1202 "username/password authentication but we "
1204 PROXY_ERROR_GENERAL, 0);
1208 if (p->state == 6) {
1210 ret = proxy_socks5_selectchap(p);
1211 if (ret) return ret;
1216 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1217 PROXY_ERROR_UNEXPECTED, 0);
1221 /* ----------------------------------------------------------------------
1222 * `Telnet' proxy type.
1224 * (This is for ad-hoc proxies where you connect to the proxy's
1225 * telnet port and send a command such as `connect host port'. The
1226 * command is configurable, since this proxy type is typically not
1227 * standardised or at all well-defined.)
1230 char *format_telnet_command(SockAddr addr, int port, Conf *conf)
1232 char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
1234 int retlen = 0, retsize = 0;
1236 #define ENSURE(n) do { \
1237 if (retsize < retlen + n) { \
1238 retsize = retlen + n + 512; \
1239 ret = sresize(ret, retsize, char); \
1243 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1244 * %%, %host, %port, %user, and %pass
1247 while (fmt[eo] != 0) {
1249 /* scan forward until we hit end-of-line,
1250 * or an escape character (\ or %) */
1251 while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
1254 /* if we hit eol, break out of our escaping loop */
1255 if (fmt[eo] == 0) break;
1257 /* if there was any unescaped text before the escape
1258 * character, send that now */
1261 memcpy(ret + retlen, fmt + so, eo - so);
1267 /* if the escape character was the last character of
1268 * the line, we'll just stop and send it. */
1269 if (fmt[eo] == 0) break;
1271 if (fmt[so] == '\\') {
1273 /* we recognize \\, \%, \r, \n, \t, \x??.
1274 * anything else, we just send unescaped (including the \).
1281 ret[retlen++] = '\\';
1287 ret[retlen++] = '%';
1293 ret[retlen++] = '\r';
1299 ret[retlen++] = '\n';
1305 ret[retlen++] = '\t';
1312 /* escaped hexadecimal value (ie. \xff) */
1313 unsigned char v = 0;
1318 if (fmt[eo] >= '0' && fmt[eo] <= '9')
1320 else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
1321 v += fmt[eo] - 'a' + 10;
1322 else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
1323 v += fmt[eo] - 'A' + 10;
1325 /* non hex character, so we abort and just
1326 * send the whole thing unescaped (including \x)
1329 ret[retlen++] = '\\';
1334 /* we only extract two hex characters */
1350 memcpy(ret+retlen, fmt + so, 2);
1357 /* % escape. we recognize %%, %host, %port, %user, %pass.
1358 * %proxyhost, %proxyport. Anything else we just send
1359 * unescaped (including the %).
1362 if (fmt[eo] == '%') {
1364 ret[retlen++] = '%';
1367 else if (strnicmp(fmt + eo, "host", 4) == 0) {
1370 sk_getaddr(addr, dest, lenof(dest));
1371 destlen = strlen(dest);
1373 memcpy(ret+retlen, dest, destlen);
1377 else if (strnicmp(fmt + eo, "port", 4) == 0) {
1378 char portstr[8], portlen;
1379 portlen = sprintf(portstr, "%i", port);
1381 memcpy(ret + retlen, portstr, portlen);
1385 else if (strnicmp(fmt + eo, "user", 4) == 0) {
1386 char *username = conf_get_str(conf, CONF_proxy_username);
1387 int userlen = strlen(username);
1389 memcpy(ret+retlen, username, userlen);
1393 else if (strnicmp(fmt + eo, "pass", 4) == 0) {
1394 char *password = conf_get_str(conf, CONF_proxy_password);
1395 int passlen = strlen(password);
1397 memcpy(ret+retlen, password, passlen);
1401 else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
1402 char *host = conf_get_str(conf, CONF_proxy_host);
1403 int phlen = strlen(host);
1405 memcpy(ret+retlen, host, phlen);
1409 else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
1410 int port = conf_get_int(conf, CONF_proxy_port);
1413 sprintf(pport, "%d", port);
1414 pplen = strlen(pport);
1416 memcpy(ret+retlen, pport, pplen);
1421 /* we don't escape this, so send the % now, and
1422 * don't advance eo, so that we'll consider the
1423 * text immediately following the % as unescaped.
1426 ret[retlen++] = '%';
1430 /* resume scanning for additional escapes after this one. */
1434 /* if there is any unescaped text at the end of the line, send it */
1437 memcpy(ret + retlen, fmt + so, eo - so);
1448 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1450 if (p->state == PROXY_CHANGE_NEW) {
1451 char *formatted_cmd;
1453 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1456 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1457 sfree(formatted_cmd);
1463 if (change == PROXY_CHANGE_CLOSING) {
1464 /* if our proxy negotiation process involves closing and opening
1465 * new sockets, then we would want to intercept this closing
1466 * callback when we were expecting it. if we aren't anticipating
1467 * a socket close, then some error must have occurred. we'll
1468 * just pass those errors up to the backend.
1470 return plug_closing(p->plug, p->closing_error_msg,
1471 p->closing_error_code,
1472 p->closing_calling_back);
1475 if (change == PROXY_CHANGE_SENT) {
1476 /* some (or all) of what we wrote to the proxy was sent.
1477 * we don't do anything new, however, until we receive the
1478 * proxy's response. we might want to set a timer so we can
1479 * timeout the proxy negotiation after a while...
1484 if (change == PROXY_CHANGE_ACCEPTING) {
1485 /* we should _never_ see this, as we are using our socket to
1486 * connect to a proxy, not accepting inbound connections.
1487 * what should we do? close the socket with an appropriate
1490 return plug_accepting(p->plug,
1491 p->accepting_constructor, p->accepting_ctx);
1494 if (change == PROXY_CHANGE_RECEIVE) {
1495 /* we have received data from the underlying socket, which
1496 * we'll need to parse, process, and respond to appropriately.
1501 /* proxy activate will have dealt with
1502 * whatever is left of the buffer */
1506 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1507 PROXY_ERROR_UNEXPECTED, 0);