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(cfg) \
18 (cfg->proxy_dns == FORCE_ON || \
19 (cfg->proxy_dns == AUTO && cfg->proxy_type != PROXY_SOCKS))
22 * Call this when proxy negotiation is complete, so that this
23 * socket can begin working normally.
25 void proxy_activate (Proxy_Socket p)
29 long output_before, output_after;
31 p->state = PROXY_STATE_ACTIVE;
33 /* we want to ignore new receive events until we have sent
34 * all of our buffered receive data.
36 sk_set_frozen(p->sub_socket, 1);
38 /* how many bytes of output have we buffered? */
39 output_before = bufchain_size(&p->pending_oob_output_data) +
40 bufchain_size(&p->pending_output_data);
41 /* and keep track of how many bytes do not get sent. */
44 /* send buffered OOB writes */
45 while (bufchain_size(&p->pending_oob_output_data) > 0) {
46 bufchain_prefix(&p->pending_oob_output_data, &data, &len);
47 output_after += sk_write_oob(p->sub_socket, data, len);
48 bufchain_consume(&p->pending_oob_output_data, len);
51 /* send buffered normal writes */
52 while (bufchain_size(&p->pending_output_data) > 0) {
53 bufchain_prefix(&p->pending_output_data, &data, &len);
54 output_after += sk_write(p->sub_socket, data, len);
55 bufchain_consume(&p->pending_output_data, len);
58 /* if we managed to send any data, let the higher levels know. */
59 if (output_after < output_before)
60 plug_sent(p->plug, output_after);
62 /* if we were asked to flush the output during
63 * the proxy negotiation process, do so now.
65 if (p->pending_flush) sk_flush(p->sub_socket);
67 /* if the backend wanted the socket unfrozen, try to unfreeze.
68 * our set_frozen handler will flush buffered receive data before
69 * unfreezing the actual underlying socket.
72 sk_set_frozen((Socket)p, 0);
75 /* basic proxy socket functions */
77 static Plug sk_proxy_plug (Socket s, Plug p)
79 Proxy_Socket ps = (Proxy_Socket) s;
86 static void sk_proxy_close (Socket s)
88 Proxy_Socket ps = (Proxy_Socket) s;
90 sk_close(ps->sub_socket);
94 static int sk_proxy_write (Socket s, const char *data, int len)
96 Proxy_Socket ps = (Proxy_Socket) s;
98 if (ps->state != PROXY_STATE_ACTIVE) {
99 bufchain_add(&ps->pending_output_data, data, len);
100 return bufchain_size(&ps->pending_output_data);
102 return sk_write(ps->sub_socket, data, len);
105 static int sk_proxy_write_oob (Socket s, const char *data, int len)
107 Proxy_Socket ps = (Proxy_Socket) s;
109 if (ps->state != PROXY_STATE_ACTIVE) {
110 bufchain_clear(&ps->pending_output_data);
111 bufchain_clear(&ps->pending_oob_output_data);
112 bufchain_add(&ps->pending_oob_output_data, data, len);
115 return sk_write_oob(ps->sub_socket, data, len);
118 static void sk_proxy_flush (Socket s)
120 Proxy_Socket ps = (Proxy_Socket) s;
122 if (ps->state != PROXY_STATE_ACTIVE) {
123 ps->pending_flush = 1;
126 sk_flush(ps->sub_socket);
129 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
131 Proxy_Socket ps = (Proxy_Socket) s;
132 sk_set_private_ptr(ps->sub_socket, ptr);
135 static void * sk_proxy_get_private_ptr (Socket s)
137 Proxy_Socket ps = (Proxy_Socket) s;
138 return sk_get_private_ptr(ps->sub_socket);
141 static void sk_proxy_set_frozen (Socket s, int is_frozen)
143 Proxy_Socket ps = (Proxy_Socket) s;
145 if (ps->state != PROXY_STATE_ACTIVE) {
146 ps->freeze = is_frozen;
150 /* handle any remaining buffered recv data first */
151 if (bufchain_size(&ps->pending_input_data) > 0) {
152 ps->freeze = is_frozen;
154 /* loop while we still have buffered data, and while we are
155 * unfrozen. the plug_receive call in the loop could result
156 * in a call back into this function refreezing the socket,
157 * so we have to check each time.
159 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
162 bufchain_prefix(&ps->pending_input_data, &data, &len);
163 plug_receive(ps->plug, 0, data, len);
164 bufchain_consume(&ps->pending_input_data, len);
167 /* if we're still frozen, we'll have to wait for another
168 * call from the backend to finish unbuffering the data.
170 if (ps->freeze) return;
173 sk_set_frozen(ps->sub_socket, is_frozen);
176 static char * sk_proxy_socket_error (Socket s)
178 Proxy_Socket ps = (Proxy_Socket) s;
179 if (ps->error != NULL || ps->sub_socket == NULL) {
182 return sk_socket_error(ps->sub_socket);
185 /* basic proxy plug functions */
187 static int plug_proxy_closing (Plug p, char *error_msg,
188 int error_code, int calling_back)
190 Proxy_Plug pp = (Proxy_Plug) p;
191 Proxy_Socket ps = pp->proxy_socket;
193 if (ps->state != PROXY_STATE_ACTIVE) {
194 ps->closing_error_msg = error_msg;
195 ps->closing_error_code = error_code;
196 ps->closing_calling_back = calling_back;
197 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
199 return plug_closing(ps->plug, error_msg,
200 error_code, calling_back);
203 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
205 Proxy_Plug pp = (Proxy_Plug) p;
206 Proxy_Socket ps = pp->proxy_socket;
208 if (ps->state != PROXY_STATE_ACTIVE) {
209 /* we will lose the urgentness of this data, but since most,
210 * if not all, of this data will be consumed by the negotiation
211 * process, hopefully it won't affect the protocol above us
213 bufchain_add(&ps->pending_input_data, data, len);
214 ps->receive_urgent = urgent;
215 ps->receive_data = data;
216 ps->receive_len = len;
217 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
219 return plug_receive(ps->plug, urgent, data, len);
222 static void plug_proxy_sent (Plug p, int bufsize)
224 Proxy_Plug pp = (Proxy_Plug) p;
225 Proxy_Socket ps = pp->proxy_socket;
227 if (ps->state != PROXY_STATE_ACTIVE) {
228 ps->sent_bufsize = bufsize;
229 ps->negotiate(ps, PROXY_CHANGE_SENT);
232 plug_sent(ps->plug, bufsize);
235 static int plug_proxy_accepting (Plug p, void *sock)
237 Proxy_Plug pp = (Proxy_Plug) p;
238 Proxy_Socket ps = pp->proxy_socket;
240 if (ps->state != PROXY_STATE_ACTIVE) {
241 ps->accepting_sock = sock;
242 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
244 return plug_accepting(ps->plug, sock);
248 * This function can accept a NULL pointer as `addr', in which case
249 * it will only check the host name.
251 static int proxy_for_destination (SockAddr addr, char *hostname, int port,
256 int hostip_len, hostname_len;
257 const char *exclude_list;
260 * Check the host name and IP against the hard-coded
261 * representations of `localhost'.
263 if (!cfg->even_proxy_localhost &&
264 (sk_hostname_is_local(hostname) ||
265 (addr && sk_address_is_local(addr))))
266 return 0; /* do not proxy */
268 /* we want a string representation of the IP address for comparisons */
270 sk_getaddr(addr, hostip, 64);
271 hostip_len = strlen(hostip);
273 hostip_len = 0; /* placate gcc; shouldn't be required */
275 hostname_len = strlen(hostname);
277 exclude_list = cfg->proxy_exclude_list;
279 /* now parse the exclude list, and see if either our IP
280 * or hostname matches anything in it.
283 while (exclude_list[s]) {
284 while (exclude_list[s] &&
285 (isspace((unsigned char)exclude_list[s]) ||
286 exclude_list[s] == ',')) s++;
288 if (!exclude_list[s]) break;
292 while (exclude_list[e] &&
293 (isalnum((unsigned char)exclude_list[e]) ||
294 exclude_list[e] == '-' ||
295 exclude_list[e] == '.' ||
296 exclude_list[e] == '*')) e++;
298 if (exclude_list[s] == '*') {
299 /* wildcard at beginning of entry */
301 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
302 exclude_list + s + 1, e - s - 1) == 0) ||
303 strnicmp(hostname + hostname_len - (e - s - 1),
304 exclude_list + s + 1, e - s - 1) == 0)
305 return 0; /* IP/hostname range excluded. do not use proxy. */
307 } else if (exclude_list[e-1] == '*') {
308 /* wildcard at end of entry */
310 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
311 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
312 return 0; /* IP/hostname range excluded. do not use proxy. */
315 /* no wildcard at either end, so let's try an absolute
316 * match (ie. a specific IP)
319 if (addr && stricmp(hostip, exclude_list + s) == 0)
320 return 0; /* IP/hostname excluded. do not use proxy. */
321 if (stricmp(hostname, exclude_list + s) == 0)
322 return 0; /* IP/hostname excluded. do not use proxy. */
327 /* Make sure we really have reached the next comma or end-of-string */
328 while (exclude_list[s] &&
329 !isspace((unsigned char)exclude_list[s]) &&
330 exclude_list[s] != ',') s++;
333 /* no matches in the exclude list, so use the proxy */
337 SockAddr name_lookup(char *host, int port, char **canonicalname,
340 if (cfg->proxy_type != PROXY_NONE &&
342 proxy_for_destination(NULL, host, port, cfg)) {
343 *canonicalname = dupstr(host);
344 return sk_nonamelookup(host);
347 return sk_namelookup(host, canonicalname);
350 Socket new_connection(SockAddr addr, char *hostname,
351 int port, int privport,
352 int oobinline, int nodelay, Plug plug,
355 static const struct socket_function_table socket_fn_table = {
361 sk_proxy_set_private_ptr,
362 sk_proxy_get_private_ptr,
364 sk_proxy_socket_error
367 static const struct plug_function_table plug_fn_table = {
374 if (cfg->proxy_type != PROXY_NONE &&
375 proxy_for_destination(addr, hostname, port, cfg))
380 char *proxy_canonical_name, *err;
382 ret = snew(struct Socket_proxy_tag);
383 ret->fn = &socket_fn_table;
384 ret->cfg = *cfg; /* STRUCTURE COPY */
386 ret->remote_addr = addr;
387 ret->remote_port = port;
390 ret->pending_flush = 0;
393 bufchain_init(&ret->pending_input_data);
394 bufchain_init(&ret->pending_output_data);
395 bufchain_init(&ret->pending_oob_output_data);
397 ret->sub_socket = NULL;
398 ret->state = PROXY_STATE_NEW;
399 ret->negotiate = NULL;
401 if (cfg->proxy_type == PROXY_HTTP) {
402 ret->negotiate = proxy_http_negotiate;
403 } else if (cfg->proxy_type == PROXY_SOCKS) {
404 if (cfg->proxy_socks_version == 4)
405 ret->negotiate = proxy_socks4_negotiate;
407 ret->negotiate = proxy_socks5_negotiate;
408 } else if (cfg->proxy_type == PROXY_TELNET) {
409 ret->negotiate = proxy_telnet_negotiate;
411 ret->error = "Proxy error: Unknown proxy method";
415 /* create the proxy plug to map calls from the actual
416 * socket into our proxy socket layer */
417 pplug = snew(struct Plug_proxy_tag);
418 pplug->fn = &plug_fn_table;
419 pplug->proxy_socket = ret;
422 proxy_addr = sk_namelookup(cfg->proxy_host,
423 &proxy_canonical_name);
424 if ((err = sk_addr_error(proxy_addr)) != NULL) {
425 ret->error = "Proxy error: Unable to resolve proxy host name";
428 sfree(proxy_canonical_name);
430 /* create the actual socket we will be using,
431 * connected to our proxy server and port.
433 ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port,
435 nodelay, (Plug) pplug);
436 if (sk_socket_error(ret->sub_socket) != NULL)
439 sk_addr_free(proxy_addr);
441 /* start the proxy negotiation process... */
442 sk_set_frozen(ret->sub_socket, 0);
443 ret->negotiate(ret, PROXY_CHANGE_NEW);
448 /* no proxy, so just return the direct socket */
449 return sk_new(addr, port, privport, oobinline, nodelay, plug);
452 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
455 /* TODO: SOCKS (and potentially others) support inbound
456 * TODO: connections via the proxy. support them.
459 return sk_newlistener(srcaddr, port, plug, local_host_only);
462 /* ----------------------------------------------------------------------
463 * HTTP CONNECT proxy type.
466 static int get_line_end (char * data, int len)
472 if (data[off] == '\n') {
473 /* we have a newline */
476 /* is that the only thing on this line? */
477 if (off <= 2) return off;
479 /* if not, then there is the possibility that this header
480 * continues onto the next line, if it starts with a space
485 data[off+1] != ' ' &&
486 data[off+1] != '\t') return off;
488 /* the line does continue, so we have to keep going
489 * until we see an the header's "real" end of line.
500 int proxy_http_negotiate (Proxy_Socket p, int change)
502 if (p->state == PROXY_STATE_NEW) {
503 /* we are just beginning the proxy negotiate process,
504 * so we'll send off the initial bits of the request.
505 * for this proxy method, it's just a simple HTTP
508 char *buf, dest[512];
510 sk_getaddr(p->remote_addr, dest, lenof(dest));
512 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
513 dest, p->remote_port, dest, p->remote_port);
514 sk_write(p->sub_socket, buf, strlen(buf));
517 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
518 char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
519 char buf2[sizeof(buf)*4/3 + 100];
521 sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
523 sprintf(buf2, "Proxy-Authorization: Basic ");
524 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
525 base64_encode_atom((unsigned char *)(buf+i),
526 (len-i > 3 ? 3 : len-i), buf2+j);
527 strcpy(buf2+j, "\r\n");
528 sk_write(p->sub_socket, buf2, strlen(buf2));
531 sk_write(p->sub_socket, "\r\n", 2);
537 if (change == PROXY_CHANGE_CLOSING) {
538 /* if our proxy negotiation process involves closing and opening
539 * new sockets, then we would want to intercept this closing
540 * callback when we were expecting it. if we aren't anticipating
541 * a socket close, then some error must have occurred. we'll
542 * just pass those errors up to the backend.
544 return plug_closing(p->plug, p->closing_error_msg,
545 p->closing_error_code,
546 p->closing_calling_back);
549 if (change == PROXY_CHANGE_SENT) {
550 /* some (or all) of what we wrote to the proxy was sent.
551 * we don't do anything new, however, until we receive the
552 * proxy's response. we might want to set a timer so we can
553 * timeout the proxy negotiation after a while...
558 if (change == PROXY_CHANGE_ACCEPTING) {
559 /* we should _never_ see this, as we are using our socket to
560 * connect to a proxy, not accepting inbound connections.
561 * what should we do? close the socket with an appropriate
564 return plug_accepting(p->plug, p->accepting_sock);
567 if (change == PROXY_CHANGE_RECEIVE) {
568 /* we have received data from the underlying socket, which
569 * we'll need to parse, process, and respond to appropriately.
578 int min_ver, maj_ver, status;
580 /* get the status line */
581 len = bufchain_size(&p->pending_input_data);
582 assert(len > 0); /* or we wouldn't be here */
583 data = snewn(len, char);
584 bufchain_fetch(&p->pending_input_data, data, len);
586 eol = get_line_end(data, len);
593 /* We can't rely on whether the %n incremented the sscanf return */
594 if (sscanf((char *)data, "HTTP/%i.%i %n",
595 &maj_ver, &min_ver, &status) < 2 || status == -1) {
596 plug_closing(p->plug, "Proxy error: HTTP response was absent",
597 PROXY_ERROR_GENERAL, 0);
602 /* remove the status line from the input buffer. */
603 bufchain_consume(&p->pending_input_data, eol);
604 if (data[status] != '2') {
608 while (eol > status &&
609 (data[eol-1] == '\r' || data[eol-1] == '\n'))
611 buf = dupprintf("Proxy error: %s", data+status);
612 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
625 /* get headers. we're done when we get a
626 * header of length 2, (ie. just "\r\n")
629 len = bufchain_size(&p->pending_input_data);
630 assert(len > 0); /* or we wouldn't be here */
631 data = snewn(len, char);
633 bufchain_fetch(&p->pending_input_data, data, len);
635 eol = get_line_end(datap, len);
642 bufchain_consume(&p->pending_input_data, eol);
645 eol = get_line_end(datap, len);
650 bufchain_consume(&p->pending_input_data, 2);
652 /* proxy activate will have dealt with
653 * whatever is left of the buffer */
663 plug_closing(p->plug, "Proxy error: unexpected proxy error",
664 PROXY_ERROR_UNEXPECTED, 0);
668 /* ----------------------------------------------------------------------
672 /* SOCKS version 4 */
673 int proxy_socks4_negotiate (Proxy_Socket p, int change)
675 if (p->state == PROXY_CHANGE_NEW) {
678 * version number (1 byte) = 4
679 * command code (1 byte)
682 * dest. port (2 bytes) [network order]
683 * dest. address (4 bytes)
684 * user ID (variable length, null terminated string)
687 int length, type, namelen;
688 char *command, addr[4], hostname[512];
690 type = sk_addrtype(p->remote_addr);
691 if (type == ADDRTYPE_IPV6) {
692 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
693 " not support IPv6", PROXY_ERROR_GENERAL, 0);
695 } else if (type == ADDRTYPE_IPV4) {
697 sk_addrcopy(p->remote_addr, addr);
698 } else { /* type == ADDRTYPE_NAME */
699 assert(type == ADDRTYPE_NAME);
700 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
701 namelen = strlen(hostname) + 1; /* include the NUL */
702 addr[0] = addr[1] = addr[2] = 0;
706 length = strlen(p->cfg.proxy_username) + namelen + 9;
707 command = snewn(length, char);
708 strcpy(command + 8, p->cfg.proxy_username);
710 command[0] = 4; /* version 4 */
711 command[1] = 1; /* CONNECT command */
714 command[2] = (char) (p->remote_port >> 8) & 0xff;
715 command[3] = (char) p->remote_port & 0xff;
718 memcpy(command + 4, addr, 4);
721 memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1,
724 sk_write(p->sub_socket, command, length);
731 if (change == PROXY_CHANGE_CLOSING) {
732 /* if our proxy negotiation process involves closing and opening
733 * new sockets, then we would want to intercept this closing
734 * callback when we were expecting it. if we aren't anticipating
735 * a socket close, then some error must have occurred. we'll
736 * just pass those errors up to the backend.
738 return plug_closing(p->plug, p->closing_error_msg,
739 p->closing_error_code,
740 p->closing_calling_back);
743 if (change == PROXY_CHANGE_SENT) {
744 /* some (or all) of what we wrote to the proxy was sent.
745 * we don't do anything new, however, until we receive the
746 * proxy's response. we might want to set a timer so we can
747 * timeout the proxy negotiation after a while...
752 if (change == PROXY_CHANGE_ACCEPTING) {
753 /* we should _never_ see this, as we are using our socket to
754 * connect to a proxy, not accepting inbound connections.
755 * what should we do? close the socket with an appropriate
758 return plug_accepting(p->plug, p->accepting_sock);
761 if (change == PROXY_CHANGE_RECEIVE) {
762 /* we have received data from the underlying socket, which
763 * we'll need to parse, process, and respond to appropriately.
768 * version number (1 byte) = 4
769 * reply code (1 byte)
770 * 90 = request granted
771 * 91 = request rejected or failed
772 * 92 = request rejected due to lack of IDENTD on client
773 * 93 = request rejected due to difference in user ID
774 * (what we sent vs. what IDENTD said)
775 * dest. port (2 bytes)
776 * dest. address (4 bytes)
781 if (bufchain_size(&p->pending_input_data) < 8)
782 return 1; /* not got anything yet */
784 /* get the response */
785 bufchain_fetch(&p->pending_input_data, data, 8);
788 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
789 "unexpected reply code version",
790 PROXY_ERROR_GENERAL, 0);
798 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
799 PROXY_ERROR_GENERAL, 0);
802 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
803 PROXY_ERROR_GENERAL, 0);
807 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
808 PROXY_ERROR_GENERAL, 0);
814 bufchain_consume(&p->pending_input_data, 8);
818 /* proxy activate will have dealt with
819 * whatever is left of the buffer */
824 plug_closing(p->plug, "Proxy error: unexpected proxy error",
825 PROXY_ERROR_UNEXPECTED, 0);
829 /* SOCKS version 5 */
830 int proxy_socks5_negotiate (Proxy_Socket p, int change)
832 if (p->state == PROXY_CHANGE_NEW) {
835 * version number (1 byte) = 5
836 * number of available authentication methods (1 byte)
837 * available authentication methods (1 byte * previous value)
838 * authentication methods:
839 * 0x00 = no authentication
841 * 0x02 = username/password
848 command[0] = 5; /* version 5 */
849 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
850 command[1] = 2; /* two methods supported: */
851 command[2] = 0x00; /* no authentication */
852 command[3] = 0x02; /* username/password */
855 command[1] = 1; /* one methods supported: */
856 command[2] = 0x00; /* no authentication */
860 sk_write(p->sub_socket, command, len);
866 if (change == PROXY_CHANGE_CLOSING) {
867 /* if our proxy negotiation process involves closing and opening
868 * new sockets, then we would want to intercept this closing
869 * callback when we were expecting it. if we aren't anticipating
870 * a socket close, then some error must have occurred. we'll
871 * just pass those errors up to the backend.
873 return plug_closing(p->plug, p->closing_error_msg,
874 p->closing_error_code,
875 p->closing_calling_back);
878 if (change == PROXY_CHANGE_SENT) {
879 /* some (or all) of what we wrote to the proxy was sent.
880 * we don't do anything new, however, until we receive the
881 * proxy's response. we might want to set a timer so we can
882 * timeout the proxy negotiation after a while...
887 if (change == PROXY_CHANGE_ACCEPTING) {
888 /* we should _never_ see this, as we are using our socket to
889 * connect to a proxy, not accepting inbound connections.
890 * what should we do? close the socket with an appropriate
893 return plug_accepting(p->plug, p->accepting_sock);
896 if (change == PROXY_CHANGE_RECEIVE) {
897 /* we have received data from the underlying socket, which
898 * we'll need to parse, process, and respond to appropriately.
904 * version number (1 byte) = 5
905 * authentication method (1 byte)
906 * authentication methods:
907 * 0x00 = no authentication
909 * 0x02 = username/password
911 * 0xff = no acceptable methods
915 if (bufchain_size(&p->pending_input_data) < 2)
916 return 1; /* not got anything yet */
918 /* get the response */
919 bufchain_fetch(&p->pending_input_data, data, 2);
922 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
923 PROXY_ERROR_GENERAL, 0);
927 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
928 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
929 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
930 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
932 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
933 PROXY_ERROR_GENERAL, 0);
936 bufchain_consume(&p->pending_input_data, 2);
941 /* password authentication reply format:
942 * version number (1 bytes) = 1
943 * reply code (1 byte)
949 if (bufchain_size(&p->pending_input_data) < 2)
950 return 1; /* not got anything yet */
952 /* get the response */
953 bufchain_fetch(&p->pending_input_data, data, 2);
956 plug_closing(p->plug, "Proxy error: SOCKS password "
957 "subnegotiation contained wrong version number",
958 PROXY_ERROR_GENERAL, 0);
964 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
965 " password authentication",
966 PROXY_ERROR_GENERAL, 0);
970 bufchain_consume(&p->pending_input_data, 2);
971 p->state = 2; /* now proceed as authenticated */
977 * version number (1 byte) = 5
978 * command code (1 byte)
982 * reserved (1 byte) = 0x00
983 * address type (1 byte)
985 * 3 = domainname (first byte has length, no terminating null)
987 * dest. address (variable)
988 * dest. port (2 bytes) [network order]
995 type = sk_addrtype(p->remote_addr);
996 if (type == ADDRTYPE_IPV4) {
997 len = 10; /* 4 hdr + 4 addr + 2 trailer */
998 command[3] = 1; /* IPv4 */
999 sk_addrcopy(p->remote_addr, command+4);
1000 } else if (type == ADDRTYPE_IPV6) {
1001 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1002 command[3] = 4; /* IPv6 */
1003 sk_addrcopy(p->remote_addr, command+4);
1005 assert(type == ADDRTYPE_NAME);
1007 sk_getaddr(p->remote_addr, command+5, 256);
1008 command[4] = strlen(command+5);
1009 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1012 command[0] = 5; /* version 5 */
1013 command[1] = 1; /* CONNECT command */
1017 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1018 command[len-1] = (char) p->remote_port & 0xff;
1020 sk_write(p->sub_socket, command, len);
1026 if (p->state == 3) {
1029 * version number (1 bytes) = 5
1030 * reply code (1 byte)
1032 * 1 = general SOCKS server failure
1033 * 2 = connection not allowed by ruleset
1034 * 3 = network unreachable
1035 * 4 = host unreachable
1036 * 5 = connection refused
1038 * 7 = command not supported
1039 * 8 = address type not supported
1040 * reserved (1 byte) = x00
1041 * address type (1 byte)
1043 * 3 = domainname (first byte has length, no terminating null)
1045 * server bound address (variable)
1046 * server bound port (2 bytes) [network order]
1051 /* First 5 bytes of packet are enough to tell its length. */
1052 if (bufchain_size(&p->pending_input_data) < 5)
1053 return 1; /* not got anything yet */
1055 /* get the response */
1056 bufchain_fetch(&p->pending_input_data, data, 5);
1059 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1060 PROXY_ERROR_GENERAL, 0);
1067 strcpy(buf, "Proxy error: ");
1070 case 1: strcat(buf, "General SOCKS server failure"); break;
1071 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1072 case 3: strcat(buf, "Network unreachable"); break;
1073 case 4: strcat(buf, "Host unreachable"); break;
1074 case 5: strcat(buf, "Connection refused"); break;
1075 case 6: strcat(buf, "TTL expired"); break;
1076 case 7: strcat(buf, "Command not supported"); break;
1077 case 8: strcat(buf, "Address type not supported"); break;
1078 default: sprintf(buf+strlen(buf),
1079 "Unrecognised SOCKS error code %d",
1083 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1089 * Eat the rest of the reply packet.
1091 len = 6; /* first 4 bytes, last 2 */
1093 case 1: len += 4; break; /* IPv4 address */
1094 case 4: len += 16; break;/* IPv6 address */
1095 case 3: len += (unsigned char)data[4]; break; /* domain name */
1097 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1098 "unrecognised address format",
1099 PROXY_ERROR_GENERAL, 0);
1102 if (bufchain_size(&p->pending_input_data) < len)
1103 return 1; /* not got whole reply yet */
1104 bufchain_consume(&p->pending_input_data, len);
1111 if (p->state == 4) {
1112 /* TODO: Handle GSSAPI authentication */
1113 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1114 PROXY_ERROR_GENERAL, 0);
1118 if (p->state == 5) {
1119 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
1120 char userpwbuf[514];
1122 ulen = strlen(p->cfg.proxy_username);
1123 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1124 plen = strlen(p->cfg.proxy_password);
1125 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1126 userpwbuf[0] = 1; /* version number of subnegotiation */
1127 userpwbuf[1] = ulen;
1128 memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
1129 userpwbuf[ulen+2] = plen;
1130 memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen);
1131 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1134 plug_closing(p->plug, "Proxy error: Server chose "
1135 "username/password authentication but we "
1137 PROXY_ERROR_GENERAL, 0);
1141 if (p->state == 6) {
1142 /* TODO: Handle CHAP authentication */
1143 plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
1144 PROXY_ERROR_GENERAL, 0);
1150 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1151 PROXY_ERROR_UNEXPECTED, 0);
1155 /* ----------------------------------------------------------------------
1156 * `Telnet' proxy type.
1158 * (This is for ad-hoc proxies where you connect to the proxy's
1159 * telnet port and send a command such as `connect host port'. The
1160 * command is configurable, since this proxy type is typically not
1161 * standardised or at all well-defined.)
1164 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1166 if (p->state == PROXY_CHANGE_NEW) {
1170 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1171 * %%, %host, %port, %user, and %pass
1174 while (p->cfg.proxy_telnet_command[eo] != 0) {
1176 /* scan forward until we hit end-of-line,
1177 * or an escape character (\ or %) */
1178 while (p->cfg.proxy_telnet_command[eo] != 0 &&
1179 p->cfg.proxy_telnet_command[eo] != '%' &&
1180 p->cfg.proxy_telnet_command[eo] != '\\') eo++;
1182 /* if we hit eol, break out of our escaping loop */
1183 if (p->cfg.proxy_telnet_command[eo] == 0) break;
1185 /* if there was any unescaped text before the escape
1186 * character, send that now */
1188 sk_write(p->sub_socket,
1189 p->cfg.proxy_telnet_command + so, eo - so);
1194 /* if the escape character was the last character of
1195 * the line, we'll just stop and send it. */
1196 if (p->cfg.proxy_telnet_command[eo] == 0) break;
1198 if (p->cfg.proxy_telnet_command[so] == '\\') {
1200 /* we recognize \\, \%, \r, \n, \t, \x??.
1201 * anything else, we just send unescaped (including the \).
1204 switch (p->cfg.proxy_telnet_command[eo]) {
1207 sk_write(p->sub_socket, "\\", 1);
1212 sk_write(p->sub_socket, "%%", 1);
1217 sk_write(p->sub_socket, "\r", 1);
1222 sk_write(p->sub_socket, "\n", 1);
1227 sk_write(p->sub_socket, "\t", 1);
1234 /* escaped hexadecimal value (ie. \xff) */
1235 unsigned char v = 0;
1240 if (p->cfg.proxy_telnet_command[eo] >= '0' &&
1241 p->cfg.proxy_telnet_command[eo] <= '9')
1242 v += p->cfg.proxy_telnet_command[eo] - '0';
1243 else if (p->cfg.proxy_telnet_command[eo] >= 'a' &&
1244 p->cfg.proxy_telnet_command[eo] <= 'f')
1245 v += p->cfg.proxy_telnet_command[eo] - 'a' + 10;
1246 else if (p->cfg.proxy_telnet_command[eo] >= 'A' &&
1247 p->cfg.proxy_telnet_command[eo] <= 'F')
1248 v += p->cfg.proxy_telnet_command[eo] - 'A' + 10;
1250 /* non hex character, so we abort and just
1251 * send the whole thing unescaped (including \x)
1253 sk_write(p->sub_socket, "\\", 1);
1258 /* we only extract two hex characters */
1260 sk_write(p->sub_socket, (char *)&v, 1);
1272 sk_write(p->sub_socket,
1273 p->cfg.proxy_telnet_command + so, 2);
1279 /* % escape. we recognize %%, %host, %port, %user, %pass.
1280 * anything else, we just send unescaped (including the %).
1283 if (p->cfg.proxy_telnet_command[eo] == '%') {
1284 sk_write(p->sub_socket, "%", 1);
1287 else if (strnicmp(p->cfg.proxy_telnet_command + eo,
1290 sk_getaddr(p->remote_addr, dest, lenof(dest));
1291 sk_write(p->sub_socket, dest, strlen(dest));
1294 else if (strnicmp(p->cfg.proxy_telnet_command + eo,
1297 sprintf(port, "%i", p->remote_port);
1298 sk_write(p->sub_socket, port, strlen(port));
1301 else if (strnicmp(p->cfg.proxy_telnet_command + eo,
1303 sk_write(p->sub_socket, p->cfg.proxy_username,
1304 strlen(p->cfg.proxy_username));
1307 else if (strnicmp(p->cfg.proxy_telnet_command + eo,
1309 sk_write(p->sub_socket, p->cfg.proxy_password,
1310 strlen(p->cfg.proxy_password));
1314 /* we don't escape this, so send the % now, and
1315 * don't advance eo, so that we'll consider the
1316 * text immediately following the % as unescaped.
1318 sk_write(p->sub_socket, "%", 1);
1322 /* resume scanning for additional escapes after this one. */
1326 /* if there is any unescaped text at the end of the line, send it */
1328 sk_write(p->sub_socket, p->cfg.proxy_telnet_command + so, eo - so);
1335 if (change == PROXY_CHANGE_CLOSING) {
1336 /* if our proxy negotiation process involves closing and opening
1337 * new sockets, then we would want to intercept this closing
1338 * callback when we were expecting it. if we aren't anticipating
1339 * a socket close, then some error must have occurred. we'll
1340 * just pass those errors up to the backend.
1342 return plug_closing(p->plug, p->closing_error_msg,
1343 p->closing_error_code,
1344 p->closing_calling_back);
1347 if (change == PROXY_CHANGE_SENT) {
1348 /* some (or all) of what we wrote to the proxy was sent.
1349 * we don't do anything new, however, until we receive the
1350 * proxy's response. we might want to set a timer so we can
1351 * timeout the proxy negotiation after a while...
1356 if (change == PROXY_CHANGE_ACCEPTING) {
1357 /* we should _never_ see this, as we are using our socket to
1358 * connect to a proxy, not accepting inbound connections.
1359 * what should we do? close the socket with an appropriate
1362 return plug_accepting(p->plug, p->accepting_sock);
1365 if (change == PROXY_CHANGE_RECEIVE) {
1366 /* we have received data from the underlying socket, which
1367 * we'll need to parse, process, and respond to appropriately.
1372 /* proxy activate will have dealt with
1373 * whatever is left of the buffer */
1377 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1378 PROXY_ERROR_UNEXPECTED, 0);