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 && \
20 cfg->proxy_type != PROXY_SOCKS4 && \
21 cfg->proxy_type != PROXY_SOCKS5))
24 * Call this when proxy negotiation is complete, so that this
25 * socket can begin working normally.
27 void proxy_activate (Proxy_Socket p)
31 long output_before, output_after;
33 p->state = PROXY_STATE_ACTIVE;
35 /* we want to ignore new receive events until we have sent
36 * all of our buffered receive data.
38 sk_set_frozen(p->sub_socket, 1);
40 /* how many bytes of output have we buffered? */
41 output_before = bufchain_size(&p->pending_oob_output_data) +
42 bufchain_size(&p->pending_output_data);
43 /* and keep track of how many bytes do not get sent. */
46 /* send buffered OOB writes */
47 while (bufchain_size(&p->pending_oob_output_data) > 0) {
48 bufchain_prefix(&p->pending_oob_output_data, &data, &len);
49 output_after += sk_write_oob(p->sub_socket, data, len);
50 bufchain_consume(&p->pending_oob_output_data, len);
53 /* send buffered normal writes */
54 while (bufchain_size(&p->pending_output_data) > 0) {
55 bufchain_prefix(&p->pending_output_data, &data, &len);
56 output_after += sk_write(p->sub_socket, data, len);
57 bufchain_consume(&p->pending_output_data, len);
60 /* if we managed to send any data, let the higher levels know. */
61 if (output_after < output_before)
62 plug_sent(p->plug, output_after);
64 /* if we were asked to flush the output during
65 * the proxy negotiation process, do so now.
67 if (p->pending_flush) sk_flush(p->sub_socket);
69 /* if the backend wanted the socket unfrozen, try to unfreeze.
70 * our set_frozen handler will flush buffered receive data before
71 * unfreezing the actual underlying socket.
74 sk_set_frozen((Socket)p, 0);
77 /* basic proxy socket functions */
79 static Plug sk_proxy_plug (Socket s, Plug p)
81 Proxy_Socket ps = (Proxy_Socket) s;
88 static void sk_proxy_close (Socket s)
90 Proxy_Socket ps = (Proxy_Socket) s;
92 sk_close(ps->sub_socket);
96 static int sk_proxy_write (Socket s, const char *data, int len)
98 Proxy_Socket ps = (Proxy_Socket) s;
100 if (ps->state != PROXY_STATE_ACTIVE) {
101 bufchain_add(&ps->pending_output_data, data, len);
102 return bufchain_size(&ps->pending_output_data);
104 return sk_write(ps->sub_socket, data, len);
107 static int sk_proxy_write_oob (Socket s, const char *data, int len)
109 Proxy_Socket ps = (Proxy_Socket) s;
111 if (ps->state != PROXY_STATE_ACTIVE) {
112 bufchain_clear(&ps->pending_output_data);
113 bufchain_clear(&ps->pending_oob_output_data);
114 bufchain_add(&ps->pending_oob_output_data, data, len);
117 return sk_write_oob(ps->sub_socket, data, len);
120 static void sk_proxy_flush (Socket s)
122 Proxy_Socket ps = (Proxy_Socket) s;
124 if (ps->state != PROXY_STATE_ACTIVE) {
125 ps->pending_flush = 1;
128 sk_flush(ps->sub_socket);
131 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
133 Proxy_Socket ps = (Proxy_Socket) s;
134 sk_set_private_ptr(ps->sub_socket, ptr);
137 static void * sk_proxy_get_private_ptr (Socket s)
139 Proxy_Socket ps = (Proxy_Socket) s;
140 return sk_get_private_ptr(ps->sub_socket);
143 static void sk_proxy_set_frozen (Socket s, int is_frozen)
145 Proxy_Socket ps = (Proxy_Socket) s;
147 if (ps->state != PROXY_STATE_ACTIVE) {
148 ps->freeze = is_frozen;
152 /* handle any remaining buffered recv data first */
153 if (bufchain_size(&ps->pending_input_data) > 0) {
154 ps->freeze = is_frozen;
156 /* loop while we still have buffered data, and while we are
157 * unfrozen. the plug_receive call in the loop could result
158 * in a call back into this function refreezing the socket,
159 * so we have to check each time.
161 while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
164 bufchain_prefix(&ps->pending_input_data, &data, &len);
165 plug_receive(ps->plug, 0, data, len);
166 bufchain_consume(&ps->pending_input_data, len);
169 /* if we're still frozen, we'll have to wait for another
170 * call from the backend to finish unbuffering the data.
172 if (ps->freeze) return;
175 sk_set_frozen(ps->sub_socket, is_frozen);
178 static const char * sk_proxy_socket_error (Socket s)
180 Proxy_Socket ps = (Proxy_Socket) s;
181 if (ps->error != NULL || ps->sub_socket == NULL) {
184 return sk_socket_error(ps->sub_socket);
187 /* basic proxy plug functions */
189 static int plug_proxy_closing (Plug p, const char *error_msg,
190 int error_code, int calling_back)
192 Proxy_Plug pp = (Proxy_Plug) p;
193 Proxy_Socket ps = pp->proxy_socket;
195 if (ps->state != PROXY_STATE_ACTIVE) {
196 ps->closing_error_msg = error_msg;
197 ps->closing_error_code = error_code;
198 ps->closing_calling_back = calling_back;
199 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
201 return plug_closing(ps->plug, error_msg,
202 error_code, calling_back);
205 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
207 Proxy_Plug pp = (Proxy_Plug) p;
208 Proxy_Socket ps = pp->proxy_socket;
210 if (ps->state != PROXY_STATE_ACTIVE) {
211 /* we will lose the urgentness of this data, but since most,
212 * if not all, of this data will be consumed by the negotiation
213 * process, hopefully it won't affect the protocol above us
215 bufchain_add(&ps->pending_input_data, data, len);
216 ps->receive_urgent = urgent;
217 ps->receive_data = data;
218 ps->receive_len = len;
219 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
221 return plug_receive(ps->plug, urgent, data, len);
224 static void plug_proxy_sent (Plug p, int bufsize)
226 Proxy_Plug pp = (Proxy_Plug) p;
227 Proxy_Socket ps = pp->proxy_socket;
229 if (ps->state != PROXY_STATE_ACTIVE) {
230 ps->sent_bufsize = bufsize;
231 ps->negotiate(ps, PROXY_CHANGE_SENT);
234 plug_sent(ps->plug, bufsize);
237 static int plug_proxy_accepting (Plug p, void *sock)
239 Proxy_Plug pp = (Proxy_Plug) p;
240 Proxy_Socket ps = pp->proxy_socket;
242 if (ps->state != PROXY_STATE_ACTIVE) {
243 ps->accepting_sock = sock;
244 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
246 return plug_accepting(ps->plug, sock);
250 * This function can accept a NULL pointer as `addr', in which case
251 * it will only check the host name.
253 static int proxy_for_destination (SockAddr addr, char *hostname, int port,
258 int hostip_len, hostname_len;
259 const char *exclude_list;
262 * Check the host name and IP against the hard-coded
263 * representations of `localhost'.
265 if (!cfg->even_proxy_localhost &&
266 (sk_hostname_is_local(hostname) ||
267 (addr && sk_address_is_local(addr))))
268 return 0; /* do not proxy */
270 /* we want a string representation of the IP address for comparisons */
272 sk_getaddr(addr, hostip, 64);
273 hostip_len = strlen(hostip);
275 hostip_len = 0; /* placate gcc; shouldn't be required */
277 hostname_len = strlen(hostname);
279 exclude_list = cfg->proxy_exclude_list;
281 /* now parse the exclude list, and see if either our IP
282 * or hostname matches anything in it.
285 while (exclude_list[s]) {
286 while (exclude_list[s] &&
287 (isspace((unsigned char)exclude_list[s]) ||
288 exclude_list[s] == ',')) s++;
290 if (!exclude_list[s]) break;
294 while (exclude_list[e] &&
295 (isalnum((unsigned char)exclude_list[e]) ||
296 exclude_list[e] == '-' ||
297 exclude_list[e] == '.' ||
298 exclude_list[e] == '*')) e++;
300 if (exclude_list[s] == '*') {
301 /* wildcard at beginning of entry */
303 if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
304 exclude_list + s + 1, e - s - 1) == 0) ||
305 strnicmp(hostname + hostname_len - (e - s - 1),
306 exclude_list + s + 1, e - s - 1) == 0)
307 return 0; /* IP/hostname range excluded. do not use proxy. */
309 } else if (exclude_list[e-1] == '*') {
310 /* wildcard at end of entry */
312 if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
313 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
314 return 0; /* IP/hostname range excluded. do not use proxy. */
317 /* no wildcard at either end, so let's try an absolute
318 * match (ie. a specific IP)
321 if (addr && stricmp(hostip, exclude_list + s) == 0)
322 return 0; /* IP/hostname excluded. do not use proxy. */
323 if (stricmp(hostname, exclude_list + s) == 0)
324 return 0; /* IP/hostname excluded. do not use proxy. */
329 /* Make sure we really have reached the next comma or end-of-string */
330 while (exclude_list[s] &&
331 !isspace((unsigned char)exclude_list[s]) &&
332 exclude_list[s] != ',') s++;
335 /* no matches in the exclude list, so use the proxy */
339 SockAddr name_lookup(char *host, int port, char **canonicalname,
342 if (cfg->proxy_type != PROXY_NONE &&
344 proxy_for_destination(NULL, host, port, cfg)) {
345 *canonicalname = dupstr(host);
346 return sk_nonamelookup(host);
349 return sk_namelookup(host, canonicalname);
352 Socket platform_new_connection(SockAddr addr, char *hostname,
353 int port, int privport,
354 int oobinline, int nodelay, Plug plug,
357 Socket new_connection(SockAddr addr, char *hostname,
358 int port, int privport,
359 int oobinline, int nodelay, Plug plug,
362 static const struct socket_function_table socket_fn_table = {
368 sk_proxy_set_private_ptr,
369 sk_proxy_get_private_ptr,
371 sk_proxy_socket_error
374 static const struct plug_function_table plug_fn_table = {
381 if (cfg->proxy_type != PROXY_NONE &&
382 proxy_for_destination(addr, hostname, port, cfg))
387 char *proxy_canonical_name;
390 if ( (sret = platform_new_connection(addr, hostname, port, privport,
391 oobinline, nodelay, plug, cfg)) )
394 ret = snew(struct Socket_proxy_tag);
395 ret->fn = &socket_fn_table;
396 ret->cfg = *cfg; /* STRUCTURE COPY */
398 ret->remote_addr = addr;
399 ret->remote_port = port;
402 ret->pending_flush = 0;
405 bufchain_init(&ret->pending_input_data);
406 bufchain_init(&ret->pending_output_data);
407 bufchain_init(&ret->pending_oob_output_data);
409 ret->sub_socket = NULL;
410 ret->state = PROXY_STATE_NEW;
411 ret->negotiate = NULL;
413 if (cfg->proxy_type == PROXY_HTTP) {
414 ret->negotiate = proxy_http_negotiate;
415 } else if (cfg->proxy_type == PROXY_SOCKS4) {
416 ret->negotiate = proxy_socks4_negotiate;
417 } else if (cfg->proxy_type == PROXY_SOCKS5) {
418 ret->negotiate = proxy_socks5_negotiate;
419 } else if (cfg->proxy_type == PROXY_TELNET) {
420 ret->negotiate = proxy_telnet_negotiate;
422 ret->error = "Proxy error: Unknown proxy method";
426 /* create the proxy plug to map calls from the actual
427 * socket into our proxy socket layer */
428 pplug = snew(struct Plug_proxy_tag);
429 pplug->fn = &plug_fn_table;
430 pplug->proxy_socket = ret;
433 proxy_addr = sk_namelookup(cfg->proxy_host,
434 &proxy_canonical_name);
435 if (sk_addr_error(proxy_addr) != NULL) {
436 ret->error = "Proxy error: Unable to resolve proxy host name";
439 sfree(proxy_canonical_name);
441 /* create the actual socket we will be using,
442 * connected to our proxy server and port.
444 ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port,
446 nodelay, (Plug) pplug);
447 if (sk_socket_error(ret->sub_socket) != NULL)
450 sk_addr_free(proxy_addr);
452 /* start the proxy negotiation process... */
453 sk_set_frozen(ret->sub_socket, 0);
454 ret->negotiate(ret, PROXY_CHANGE_NEW);
459 /* no proxy, so just return the direct socket */
460 return sk_new(addr, port, privport, oobinline, nodelay, plug);
463 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
466 /* TODO: SOCKS (and potentially others) support inbound
467 * TODO: connections via the proxy. support them.
470 return sk_newlistener(srcaddr, port, plug, local_host_only);
473 /* ----------------------------------------------------------------------
474 * HTTP CONNECT proxy type.
477 static int get_line_end (char * data, int len)
483 if (data[off] == '\n') {
484 /* we have a newline */
487 /* is that the only thing on this line? */
488 if (off <= 2) return off;
490 /* if not, then there is the possibility that this header
491 * continues onto the next line, if it starts with a space
496 data[off+1] != ' ' &&
497 data[off+1] != '\t') return off;
499 /* the line does continue, so we have to keep going
500 * until we see an the header's "real" end of line.
511 int proxy_http_negotiate (Proxy_Socket p, int change)
513 if (p->state == PROXY_STATE_NEW) {
514 /* we are just beginning the proxy negotiate process,
515 * so we'll send off the initial bits of the request.
516 * for this proxy method, it's just a simple HTTP
519 char *buf, dest[512];
521 sk_getaddr(p->remote_addr, dest, lenof(dest));
523 buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
524 dest, p->remote_port, dest, p->remote_port);
525 sk_write(p->sub_socket, buf, strlen(buf));
528 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
529 char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
530 char buf2[sizeof(buf)*4/3 + 100];
532 sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
534 sprintf(buf2, "Proxy-Authorization: Basic ");
535 for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
536 base64_encode_atom((unsigned char *)(buf+i),
537 (len-i > 3 ? 3 : len-i), buf2+j);
538 strcpy(buf2+j, "\r\n");
539 sk_write(p->sub_socket, buf2, strlen(buf2));
542 sk_write(p->sub_socket, "\r\n", 2);
548 if (change == PROXY_CHANGE_CLOSING) {
549 /* if our proxy negotiation process involves closing and opening
550 * new sockets, then we would want to intercept this closing
551 * callback when we were expecting it. if we aren't anticipating
552 * a socket close, then some error must have occurred. we'll
553 * just pass those errors up to the backend.
555 return plug_closing(p->plug, p->closing_error_msg,
556 p->closing_error_code,
557 p->closing_calling_back);
560 if (change == PROXY_CHANGE_SENT) {
561 /* some (or all) of what we wrote to the proxy was sent.
562 * we don't do anything new, however, until we receive the
563 * proxy's response. we might want to set a timer so we can
564 * timeout the proxy negotiation after a while...
569 if (change == PROXY_CHANGE_ACCEPTING) {
570 /* we should _never_ see this, as we are using our socket to
571 * connect to a proxy, not accepting inbound connections.
572 * what should we do? close the socket with an appropriate
575 return plug_accepting(p->plug, p->accepting_sock);
578 if (change == PROXY_CHANGE_RECEIVE) {
579 /* we have received data from the underlying socket, which
580 * we'll need to parse, process, and respond to appropriately.
589 int min_ver, maj_ver, status;
591 /* get the status line */
592 len = bufchain_size(&p->pending_input_data);
593 assert(len > 0); /* or we wouldn't be here */
594 data = snewn(len, char);
595 bufchain_fetch(&p->pending_input_data, data, len);
597 eol = get_line_end(data, len);
604 /* We can't rely on whether the %n incremented the sscanf return */
605 if (sscanf((char *)data, "HTTP/%i.%i %n",
606 &maj_ver, &min_ver, &status) < 2 || status == -1) {
607 plug_closing(p->plug, "Proxy error: HTTP response was absent",
608 PROXY_ERROR_GENERAL, 0);
613 /* remove the status line from the input buffer. */
614 bufchain_consume(&p->pending_input_data, eol);
615 if (data[status] != '2') {
619 while (eol > status &&
620 (data[eol-1] == '\r' || data[eol-1] == '\n'))
622 buf = dupprintf("Proxy error: %s", data+status);
623 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
636 /* get headers. we're done when we get a
637 * header of length 2, (ie. just "\r\n")
640 len = bufchain_size(&p->pending_input_data);
641 assert(len > 0); /* or we wouldn't be here */
642 data = snewn(len, char);
644 bufchain_fetch(&p->pending_input_data, data, len);
646 eol = get_line_end(datap, len);
653 bufchain_consume(&p->pending_input_data, eol);
656 eol = get_line_end(datap, len);
661 bufchain_consume(&p->pending_input_data, 2);
663 /* proxy activate will have dealt with
664 * whatever is left of the buffer */
674 plug_closing(p->plug, "Proxy error: unexpected proxy error",
675 PROXY_ERROR_UNEXPECTED, 0);
679 /* ----------------------------------------------------------------------
683 /* SOCKS version 4 */
684 int proxy_socks4_negotiate (Proxy_Socket p, int change)
686 if (p->state == PROXY_CHANGE_NEW) {
689 * version number (1 byte) = 4
690 * command code (1 byte)
693 * dest. port (2 bytes) [network order]
694 * dest. address (4 bytes)
695 * user ID (variable length, null terminated string)
698 int length, type, namelen;
699 char *command, addr[4], hostname[512];
701 type = sk_addrtype(p->remote_addr);
702 if (type == ADDRTYPE_IPV6) {
703 plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
704 " not support IPv6", PROXY_ERROR_GENERAL, 0);
706 } else if (type == ADDRTYPE_IPV4) {
708 sk_addrcopy(p->remote_addr, addr);
709 } else { /* type == ADDRTYPE_NAME */
710 assert(type == ADDRTYPE_NAME);
711 sk_getaddr(p->remote_addr, hostname, lenof(hostname));
712 namelen = strlen(hostname) + 1; /* include the NUL */
713 addr[0] = addr[1] = addr[2] = 0;
717 length = strlen(p->cfg.proxy_username) + namelen + 9;
718 command = snewn(length, char);
719 strcpy(command + 8, p->cfg.proxy_username);
721 command[0] = 4; /* version 4 */
722 command[1] = 1; /* CONNECT command */
725 command[2] = (char) (p->remote_port >> 8) & 0xff;
726 command[3] = (char) p->remote_port & 0xff;
729 memcpy(command + 4, addr, 4);
732 memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1,
735 sk_write(p->sub_socket, command, length);
742 if (change == PROXY_CHANGE_CLOSING) {
743 /* if our proxy negotiation process involves closing and opening
744 * new sockets, then we would want to intercept this closing
745 * callback when we were expecting it. if we aren't anticipating
746 * a socket close, then some error must have occurred. we'll
747 * just pass those errors up to the backend.
749 return plug_closing(p->plug, p->closing_error_msg,
750 p->closing_error_code,
751 p->closing_calling_back);
754 if (change == PROXY_CHANGE_SENT) {
755 /* some (or all) of what we wrote to the proxy was sent.
756 * we don't do anything new, however, until we receive the
757 * proxy's response. we might want to set a timer so we can
758 * timeout the proxy negotiation after a while...
763 if (change == PROXY_CHANGE_ACCEPTING) {
764 /* we should _never_ see this, as we are using our socket to
765 * connect to a proxy, not accepting inbound connections.
766 * what should we do? close the socket with an appropriate
769 return plug_accepting(p->plug, p->accepting_sock);
772 if (change == PROXY_CHANGE_RECEIVE) {
773 /* we have received data from the underlying socket, which
774 * we'll need to parse, process, and respond to appropriately.
779 * version number (1 byte) = 4
780 * reply code (1 byte)
781 * 90 = request granted
782 * 91 = request rejected or failed
783 * 92 = request rejected due to lack of IDENTD on client
784 * 93 = request rejected due to difference in user ID
785 * (what we sent vs. what IDENTD said)
786 * dest. port (2 bytes)
787 * dest. address (4 bytes)
792 if (bufchain_size(&p->pending_input_data) < 8)
793 return 1; /* not got anything yet */
795 /* get the response */
796 bufchain_fetch(&p->pending_input_data, data, 8);
799 plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
800 "unexpected reply code version",
801 PROXY_ERROR_GENERAL, 0);
809 plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
810 PROXY_ERROR_GENERAL, 0);
813 plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
814 PROXY_ERROR_GENERAL, 0);
818 plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
819 PROXY_ERROR_GENERAL, 0);
825 bufchain_consume(&p->pending_input_data, 8);
829 /* proxy activate will have dealt with
830 * whatever is left of the buffer */
835 plug_closing(p->plug, "Proxy error: unexpected proxy error",
836 PROXY_ERROR_UNEXPECTED, 0);
840 /* SOCKS version 5 */
841 int proxy_socks5_negotiate (Proxy_Socket p, int change)
843 if (p->state == PROXY_CHANGE_NEW) {
846 * version number (1 byte) = 5
847 * number of available authentication methods (1 byte)
848 * available authentication methods (1 byte * previous value)
849 * authentication methods:
850 * 0x00 = no authentication
852 * 0x02 = username/password
859 command[0] = 5; /* version 5 */
860 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
861 command[1] = 2; /* two methods supported: */
862 command[2] = 0x00; /* no authentication */
863 command[3] = 0x02; /* username/password */
866 command[1] = 1; /* one methods supported: */
867 command[2] = 0x00; /* no authentication */
871 sk_write(p->sub_socket, command, len);
877 if (change == PROXY_CHANGE_CLOSING) {
878 /* if our proxy negotiation process involves closing and opening
879 * new sockets, then we would want to intercept this closing
880 * callback when we were expecting it. if we aren't anticipating
881 * a socket close, then some error must have occurred. we'll
882 * just pass those errors up to the backend.
884 return plug_closing(p->plug, p->closing_error_msg,
885 p->closing_error_code,
886 p->closing_calling_back);
889 if (change == PROXY_CHANGE_SENT) {
890 /* some (or all) of what we wrote to the proxy was sent.
891 * we don't do anything new, however, until we receive the
892 * proxy's response. we might want to set a timer so we can
893 * timeout the proxy negotiation after a while...
898 if (change == PROXY_CHANGE_ACCEPTING) {
899 /* we should _never_ see this, as we are using our socket to
900 * connect to a proxy, not accepting inbound connections.
901 * what should we do? close the socket with an appropriate
904 return plug_accepting(p->plug, p->accepting_sock);
907 if (change == PROXY_CHANGE_RECEIVE) {
908 /* we have received data from the underlying socket, which
909 * we'll need to parse, process, and respond to appropriately.
915 * version number (1 byte) = 5
916 * authentication method (1 byte)
917 * authentication methods:
918 * 0x00 = no authentication
920 * 0x02 = username/password
922 * 0xff = no acceptable methods
926 if (bufchain_size(&p->pending_input_data) < 2)
927 return 1; /* not got anything yet */
929 /* get the response */
930 bufchain_fetch(&p->pending_input_data, data, 2);
933 plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
934 PROXY_ERROR_GENERAL, 0);
938 if (data[1] == 0x00) p->state = 2; /* no authentication needed */
939 else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
940 else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
941 else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
943 plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
944 PROXY_ERROR_GENERAL, 0);
947 bufchain_consume(&p->pending_input_data, 2);
952 /* password authentication reply format:
953 * version number (1 bytes) = 1
954 * reply code (1 byte)
960 if (bufchain_size(&p->pending_input_data) < 2)
961 return 1; /* not got anything yet */
963 /* get the response */
964 bufchain_fetch(&p->pending_input_data, data, 2);
967 plug_closing(p->plug, "Proxy error: SOCKS password "
968 "subnegotiation contained wrong version number",
969 PROXY_ERROR_GENERAL, 0);
975 plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
976 " password authentication",
977 PROXY_ERROR_GENERAL, 0);
981 bufchain_consume(&p->pending_input_data, 2);
982 p->state = 2; /* now proceed as authenticated */
988 * version number (1 byte) = 5
989 * command code (1 byte)
993 * reserved (1 byte) = 0x00
994 * address type (1 byte)
996 * 3 = domainname (first byte has length, no terminating null)
998 * dest. address (variable)
999 * dest. port (2 bytes) [network order]
1006 type = sk_addrtype(p->remote_addr);
1007 if (type == ADDRTYPE_IPV4) {
1008 len = 10; /* 4 hdr + 4 addr + 2 trailer */
1009 command[3] = 1; /* IPv4 */
1010 sk_addrcopy(p->remote_addr, command+4);
1011 } else if (type == ADDRTYPE_IPV6) {
1012 len = 22; /* 4 hdr + 16 addr + 2 trailer */
1013 command[3] = 4; /* IPv6 */
1014 sk_addrcopy(p->remote_addr, command+4);
1016 assert(type == ADDRTYPE_NAME);
1018 sk_getaddr(p->remote_addr, command+5, 256);
1019 command[4] = strlen(command+5);
1020 len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1023 command[0] = 5; /* version 5 */
1024 command[1] = 1; /* CONNECT command */
1028 command[len-2] = (char) (p->remote_port >> 8) & 0xff;
1029 command[len-1] = (char) p->remote_port & 0xff;
1031 sk_write(p->sub_socket, command, len);
1037 if (p->state == 3) {
1040 * version number (1 bytes) = 5
1041 * reply code (1 byte)
1043 * 1 = general SOCKS server failure
1044 * 2 = connection not allowed by ruleset
1045 * 3 = network unreachable
1046 * 4 = host unreachable
1047 * 5 = connection refused
1049 * 7 = command not supported
1050 * 8 = address type not supported
1051 * reserved (1 byte) = x00
1052 * address type (1 byte)
1054 * 3 = domainname (first byte has length, no terminating null)
1056 * server bound address (variable)
1057 * server bound port (2 bytes) [network order]
1062 /* First 5 bytes of packet are enough to tell its length. */
1063 if (bufchain_size(&p->pending_input_data) < 5)
1064 return 1; /* not got anything yet */
1066 /* get the response */
1067 bufchain_fetch(&p->pending_input_data, data, 5);
1070 plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
1071 PROXY_ERROR_GENERAL, 0);
1078 strcpy(buf, "Proxy error: ");
1081 case 1: strcat(buf, "General SOCKS server failure"); break;
1082 case 2: strcat(buf, "Connection not allowed by ruleset"); break;
1083 case 3: strcat(buf, "Network unreachable"); break;
1084 case 4: strcat(buf, "Host unreachable"); break;
1085 case 5: strcat(buf, "Connection refused"); break;
1086 case 6: strcat(buf, "TTL expired"); break;
1087 case 7: strcat(buf, "Command not supported"); break;
1088 case 8: strcat(buf, "Address type not supported"); break;
1089 default: sprintf(buf+strlen(buf),
1090 "Unrecognised SOCKS error code %d",
1094 plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
1100 * Eat the rest of the reply packet.
1102 len = 6; /* first 4 bytes, last 2 */
1104 case 1: len += 4; break; /* IPv4 address */
1105 case 4: len += 16; break;/* IPv6 address */
1106 case 3: len += (unsigned char)data[4]; break; /* domain name */
1108 plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
1109 "unrecognised address format",
1110 PROXY_ERROR_GENERAL, 0);
1113 if (bufchain_size(&p->pending_input_data) < len)
1114 return 1; /* not got whole reply yet */
1115 bufchain_consume(&p->pending_input_data, len);
1122 if (p->state == 4) {
1123 /* TODO: Handle GSSAPI authentication */
1124 plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
1125 PROXY_ERROR_GENERAL, 0);
1129 if (p->state == 5) {
1130 if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
1131 char userpwbuf[514];
1133 ulen = strlen(p->cfg.proxy_username);
1134 if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
1135 plen = strlen(p->cfg.proxy_password);
1136 if (plen > 255) plen = 255; if (plen < 1) plen = 1;
1137 userpwbuf[0] = 1; /* version number of subnegotiation */
1138 userpwbuf[1] = ulen;
1139 memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
1140 userpwbuf[ulen+2] = plen;
1141 memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen);
1142 sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
1145 plug_closing(p->plug, "Proxy error: Server chose "
1146 "username/password authentication but we "
1148 PROXY_ERROR_GENERAL, 0);
1152 if (p->state == 6) {
1153 /* TODO: Handle CHAP authentication */
1154 plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
1155 PROXY_ERROR_GENERAL, 0);
1161 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1162 PROXY_ERROR_UNEXPECTED, 0);
1166 /* ----------------------------------------------------------------------
1167 * `Telnet' proxy type.
1169 * (This is for ad-hoc proxies where you connect to the proxy's
1170 * telnet port and send a command such as `connect host port'. The
1171 * command is configurable, since this proxy type is typically not
1172 * standardised or at all well-defined.)
1175 char *format_telnet_command(SockAddr addr, int port, const Config *cfg)
1178 int retlen = 0, retsize = 0;
1180 #define ENSURE(n) do { \
1181 if (retsize < retlen + n) { \
1182 retsize = retlen + n + 512; \
1183 ret = sresize(ret, retsize, char); \
1187 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1188 * %%, %host, %port, %user, and %pass
1191 while (cfg->proxy_telnet_command[eo] != 0) {
1193 /* scan forward until we hit end-of-line,
1194 * or an escape character (\ or %) */
1195 while (cfg->proxy_telnet_command[eo] != 0 &&
1196 cfg->proxy_telnet_command[eo] != '%' &&
1197 cfg->proxy_telnet_command[eo] != '\\') eo++;
1199 /* if we hit eol, break out of our escaping loop */
1200 if (cfg->proxy_telnet_command[eo] == 0) break;
1202 /* if there was any unescaped text before the escape
1203 * character, send that now */
1206 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1212 /* if the escape character was the last character of
1213 * the line, we'll just stop and send it. */
1214 if (cfg->proxy_telnet_command[eo] == 0) break;
1216 if (cfg->proxy_telnet_command[so] == '\\') {
1218 /* we recognize \\, \%, \r, \n, \t, \x??.
1219 * anything else, we just send unescaped (including the \).
1222 switch (cfg->proxy_telnet_command[eo]) {
1226 ret[retlen++] = '\\';
1232 ret[retlen++] = '%';
1238 ret[retlen++] = '\r';
1244 ret[retlen++] = '\n';
1250 ret[retlen++] = '\t';
1257 /* escaped hexadecimal value (ie. \xff) */
1258 unsigned char v = 0;
1263 if (cfg->proxy_telnet_command[eo] >= '0' &&
1264 cfg->proxy_telnet_command[eo] <= '9')
1265 v += cfg->proxy_telnet_command[eo] - '0';
1266 else if (cfg->proxy_telnet_command[eo] >= 'a' &&
1267 cfg->proxy_telnet_command[eo] <= 'f')
1268 v += cfg->proxy_telnet_command[eo] - 'a' + 10;
1269 else if (cfg->proxy_telnet_command[eo] >= 'A' &&
1270 cfg->proxy_telnet_command[eo] <= 'F')
1271 v += cfg->proxy_telnet_command[eo] - 'A' + 10;
1273 /* non hex character, so we abort and just
1274 * send the whole thing unescaped (including \x)
1277 ret[retlen++] = '\\';
1282 /* we only extract two hex characters */
1298 memcpy(ret+retlen, cfg->proxy_telnet_command + so, 2);
1305 /* % escape. we recognize %%, %host, %port, %user, %pass.
1306 * anything else, we just send unescaped (including the %).
1309 if (cfg->proxy_telnet_command[eo] == '%') {
1311 ret[retlen++] = '%';
1314 else if (strnicmp(cfg->proxy_telnet_command + eo,
1318 sk_getaddr(addr, dest, lenof(dest));
1319 destlen = strlen(dest);
1321 memcpy(ret+retlen, dest, destlen);
1325 else if (strnicmp(cfg->proxy_telnet_command + eo,
1327 char portstr[8], portlen;
1328 portlen = sprintf(portstr, "%i", port);
1330 memcpy(ret + retlen, portstr, portlen);
1334 else if (strnicmp(cfg->proxy_telnet_command + eo,
1336 int userlen = strlen(cfg->proxy_username);
1338 memcpy(ret+retlen, cfg->proxy_username, userlen);
1342 else if (strnicmp(cfg->proxy_telnet_command + eo,
1344 int passlen = strlen(cfg->proxy_password);
1346 memcpy(ret+retlen, cfg->proxy_password, passlen);
1351 /* we don't escape this, so send the % now, and
1352 * don't advance eo, so that we'll consider the
1353 * text immediately following the % as unescaped.
1356 ret[retlen++] = '%';
1360 /* resume scanning for additional escapes after this one. */
1364 /* if there is any unescaped text at the end of the line, send it */
1367 memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so);
1378 int proxy_telnet_negotiate (Proxy_Socket p, int change)
1380 if (p->state == PROXY_CHANGE_NEW) {
1381 char *formatted_cmd;
1383 formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
1386 sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
1387 sfree(formatted_cmd);
1393 if (change == PROXY_CHANGE_CLOSING) {
1394 /* if our proxy negotiation process involves closing and opening
1395 * new sockets, then we would want to intercept this closing
1396 * callback when we were expecting it. if we aren't anticipating
1397 * a socket close, then some error must have occurred. we'll
1398 * just pass those errors up to the backend.
1400 return plug_closing(p->plug, p->closing_error_msg,
1401 p->closing_error_code,
1402 p->closing_calling_back);
1405 if (change == PROXY_CHANGE_SENT) {
1406 /* some (or all) of what we wrote to the proxy was sent.
1407 * we don't do anything new, however, until we receive the
1408 * proxy's response. we might want to set a timer so we can
1409 * timeout the proxy negotiation after a while...
1414 if (change == PROXY_CHANGE_ACCEPTING) {
1415 /* we should _never_ see this, as we are using our socket to
1416 * connect to a proxy, not accepting inbound connections.
1417 * what should we do? close the socket with an appropriate
1420 return plug_accepting(p->plug, p->accepting_sock);
1423 if (change == PROXY_CHANGE_RECEIVE) {
1424 /* we have received data from the underlying socket, which
1425 * we'll need to parse, process, and respond to appropriately.
1430 /* proxy activate will have dealt with
1431 * whatever is left of the buffer */
1435 plug_closing(p->plug, "Proxy error: Unexpected proxy error",
1436 PROXY_ERROR_UNEXPECTED, 0);