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
);
93 sk_addr_free(ps
->remote_addr
);
97 static int sk_proxy_write (Socket s
, const char *data
, int len
)
99 Proxy_Socket ps
= (Proxy_Socket
) s
;
101 if (ps
->state
!= PROXY_STATE_ACTIVE
) {
102 bufchain_add(&ps
->pending_output_data
, data
, len
);
103 return bufchain_size(&ps
->pending_output_data
);
105 return sk_write(ps
->sub_socket
, data
, len
);
108 static int sk_proxy_write_oob (Socket s
, const char *data
, int len
)
110 Proxy_Socket ps
= (Proxy_Socket
) s
;
112 if (ps
->state
!= PROXY_STATE_ACTIVE
) {
113 bufchain_clear(&ps
->pending_output_data
);
114 bufchain_clear(&ps
->pending_oob_output_data
);
115 bufchain_add(&ps
->pending_oob_output_data
, data
, len
);
118 return sk_write_oob(ps
->sub_socket
, data
, len
);
121 static void sk_proxy_flush (Socket s
)
123 Proxy_Socket ps
= (Proxy_Socket
) s
;
125 if (ps
->state
!= PROXY_STATE_ACTIVE
) {
126 ps
->pending_flush
= 1;
129 sk_flush(ps
->sub_socket
);
132 static void sk_proxy_set_private_ptr (Socket s
, void *ptr
)
134 Proxy_Socket ps
= (Proxy_Socket
) s
;
135 sk_set_private_ptr(ps
->sub_socket
, ptr
);
138 static void * sk_proxy_get_private_ptr (Socket s
)
140 Proxy_Socket ps
= (Proxy_Socket
) s
;
141 return sk_get_private_ptr(ps
->sub_socket
);
144 static void sk_proxy_set_frozen (Socket s
, int is_frozen
)
146 Proxy_Socket ps
= (Proxy_Socket
) s
;
148 if (ps
->state
!= PROXY_STATE_ACTIVE
) {
149 ps
->freeze
= is_frozen
;
153 /* handle any remaining buffered recv data first */
154 if (bufchain_size(&ps
->pending_input_data
) > 0) {
155 ps
->freeze
= is_frozen
;
157 /* loop while we still have buffered data, and while we are
158 * unfrozen. the plug_receive call in the loop could result
159 * in a call back into this function refreezing the socket,
160 * so we have to check each time.
162 while (!ps
->freeze
&& bufchain_size(&ps
->pending_input_data
) > 0) {
165 bufchain_prefix(&ps
->pending_input_data
, &data
, &len
);
166 plug_receive(ps
->plug
, 0, data
, len
);
167 bufchain_consume(&ps
->pending_input_data
, len
);
170 /* if we're still frozen, we'll have to wait for another
171 * call from the backend to finish unbuffering the data.
173 if (ps
->freeze
) return;
176 sk_set_frozen(ps
->sub_socket
, is_frozen
);
179 static const char * sk_proxy_socket_error (Socket s
)
181 Proxy_Socket ps
= (Proxy_Socket
) s
;
182 if (ps
->error
!= NULL
|| ps
->sub_socket
== NULL
) {
185 return sk_socket_error(ps
->sub_socket
);
188 /* basic proxy plug functions */
190 static int plug_proxy_closing (Plug p
, const char *error_msg
,
191 int error_code
, int calling_back
)
193 Proxy_Plug pp
= (Proxy_Plug
) p
;
194 Proxy_Socket ps
= pp
->proxy_socket
;
196 if (ps
->state
!= PROXY_STATE_ACTIVE
) {
197 ps
->closing_error_msg
= error_msg
;
198 ps
->closing_error_code
= error_code
;
199 ps
->closing_calling_back
= calling_back
;
200 return ps
->negotiate(ps
, PROXY_CHANGE_CLOSING
);
202 return plug_closing(ps
->plug
, error_msg
,
203 error_code
, calling_back
);
206 static int plug_proxy_receive (Plug p
, int urgent
, char *data
, int len
)
208 Proxy_Plug pp
= (Proxy_Plug
) p
;
209 Proxy_Socket ps
= pp
->proxy_socket
;
211 if (ps
->state
!= PROXY_STATE_ACTIVE
) {
212 /* we will lose the urgentness of this data, but since most,
213 * if not all, of this data will be consumed by the negotiation
214 * process, hopefully it won't affect the protocol above us
216 bufchain_add(&ps
->pending_input_data
, data
, len
);
217 ps
->receive_urgent
= urgent
;
218 ps
->receive_data
= data
;
219 ps
->receive_len
= len
;
220 return ps
->negotiate(ps
, PROXY_CHANGE_RECEIVE
);
222 return plug_receive(ps
->plug
, urgent
, data
, len
);
225 static void plug_proxy_sent (Plug p
, int bufsize
)
227 Proxy_Plug pp
= (Proxy_Plug
) p
;
228 Proxy_Socket ps
= pp
->proxy_socket
;
230 if (ps
->state
!= PROXY_STATE_ACTIVE
) {
231 ps
->sent_bufsize
= bufsize
;
232 ps
->negotiate(ps
, PROXY_CHANGE_SENT
);
235 plug_sent(ps
->plug
, bufsize
);
238 static int plug_proxy_accepting (Plug p
, OSSocket sock
)
240 Proxy_Plug pp
= (Proxy_Plug
) p
;
241 Proxy_Socket ps
= pp
->proxy_socket
;
243 if (ps
->state
!= PROXY_STATE_ACTIVE
) {
244 ps
->accepting_sock
= sock
;
245 return ps
->negotiate(ps
, PROXY_CHANGE_ACCEPTING
);
247 return plug_accepting(ps
->plug
, sock
);
251 * This function can accept a NULL pointer as `addr', in which case
252 * it will only check the host name.
254 static int proxy_for_destination (SockAddr addr
, char *hostname
, int port
,
259 int hostip_len
, hostname_len
;
260 const char *exclude_list
;
263 * Check the host name and IP against the hard-coded
264 * representations of `localhost'.
266 if (!cfg
->even_proxy_localhost
&&
267 (sk_hostname_is_local(hostname
) ||
268 (addr
&& sk_address_is_local(addr
))))
269 return 0; /* do not proxy */
271 /* we want a string representation of the IP address for comparisons */
273 sk_getaddr(addr
, hostip
, 64);
274 hostip_len
= strlen(hostip
);
276 hostip_len
= 0; /* placate gcc; shouldn't be required */
278 hostname_len
= strlen(hostname
);
280 exclude_list
= cfg
->proxy_exclude_list
;
282 /* now parse the exclude list, and see if either our IP
283 * or hostname matches anything in it.
286 while (exclude_list
[s
]) {
287 while (exclude_list
[s
] &&
288 (isspace((unsigned char)exclude_list
[s
]) ||
289 exclude_list
[s
] == ',')) s
++;
291 if (!exclude_list
[s
]) break;
295 while (exclude_list
[e
] &&
296 (isalnum((unsigned char)exclude_list
[e
]) ||
297 exclude_list
[e
] == '-' ||
298 exclude_list
[e
] == '.' ||
299 exclude_list
[e
] == '*')) e
++;
301 if (exclude_list
[s
] == '*') {
302 /* wildcard at beginning of entry */
304 if ((addr
&& strnicmp(hostip
+ hostip_len
- (e
- s
- 1),
305 exclude_list
+ s
+ 1, e
- s
- 1) == 0) ||
306 strnicmp(hostname
+ hostname_len
- (e
- s
- 1),
307 exclude_list
+ s
+ 1, e
- s
- 1) == 0)
308 return 0; /* IP/hostname range excluded. do not use proxy. */
310 } else if (exclude_list
[e
-1] == '*') {
311 /* wildcard at end of entry */
313 if ((addr
&& strnicmp(hostip
, exclude_list
+ s
, e
- s
- 1) == 0) ||
314 strnicmp(hostname
, exclude_list
+ s
, e
- s
- 1) == 0)
315 return 0; /* IP/hostname range excluded. do not use proxy. */
318 /* no wildcard at either end, so let's try an absolute
319 * match (ie. a specific IP)
322 if (addr
&& strnicmp(hostip
, exclude_list
+ s
, e
- s
) == 0)
323 return 0; /* IP/hostname excluded. do not use proxy. */
324 if (strnicmp(hostname
, exclude_list
+ s
, e
- s
) == 0)
325 return 0; /* IP/hostname excluded. do not use proxy. */
330 /* Make sure we really have reached the next comma or end-of-string */
331 while (exclude_list
[s
] &&
332 !isspace((unsigned char)exclude_list
[s
]) &&
333 exclude_list
[s
] != ',') s
++;
336 /* no matches in the exclude list, so use the proxy */
340 SockAddr
name_lookup(char *host
, int port
, char **canonicalname
,
343 if (cfg
->proxy_type
!= PROXY_NONE
&&
345 proxy_for_destination(NULL
, host
, port
, cfg
)) {
346 *canonicalname
= dupstr(host
);
347 return sk_nonamelookup(host
);
350 return sk_namelookup(host
, canonicalname
);
353 Socket
new_connection(SockAddr addr
, char *hostname
,
354 int port
, int privport
,
355 int oobinline
, int nodelay
, Plug plug
,
358 static const struct socket_function_table socket_fn_table
= {
364 sk_proxy_set_private_ptr
,
365 sk_proxy_get_private_ptr
,
367 sk_proxy_socket_error
370 static const struct plug_function_table plug_fn_table
= {
377 if (cfg
->proxy_type
!= PROXY_NONE
&&
378 proxy_for_destination(addr
, hostname
, port
, cfg
))
383 char *proxy_canonical_name
;
386 if ((sret
= platform_new_connection(addr
, hostname
, port
, privport
,
387 oobinline
, nodelay
, plug
, cfg
)) !=
391 ret
= snew(struct Socket_proxy_tag
);
392 ret
->fn
= &socket_fn_table
;
393 ret
->cfg
= *cfg
; /* STRUCTURE COPY */
395 ret
->remote_addr
= addr
; /* will need to be freed on close */
396 ret
->remote_port
= port
;
399 ret
->pending_flush
= 0;
402 bufchain_init(&ret
->pending_input_data
);
403 bufchain_init(&ret
->pending_output_data
);
404 bufchain_init(&ret
->pending_oob_output_data
);
406 ret
->sub_socket
= NULL
;
407 ret
->state
= PROXY_STATE_NEW
;
408 ret
->negotiate
= NULL
;
410 if (cfg
->proxy_type
== PROXY_HTTP
) {
411 ret
->negotiate
= proxy_http_negotiate
;
412 } else if (cfg
->proxy_type
== PROXY_SOCKS4
) {
413 ret
->negotiate
= proxy_socks4_negotiate
;
414 } else if (cfg
->proxy_type
== PROXY_SOCKS5
) {
415 ret
->negotiate
= proxy_socks5_negotiate
;
416 } else if (cfg
->proxy_type
== PROXY_TELNET
) {
417 ret
->negotiate
= proxy_telnet_negotiate
;
419 ret
->error
= "Proxy error: Unknown proxy method";
423 /* create the proxy plug to map calls from the actual
424 * socket into our proxy socket layer */
425 pplug
= snew(struct Plug_proxy_tag
);
426 pplug
->fn
= &plug_fn_table
;
427 pplug
->proxy_socket
= ret
;
430 proxy_addr
= sk_namelookup(cfg
->proxy_host
,
431 &proxy_canonical_name
);
432 if (sk_addr_error(proxy_addr
) != NULL
) {
433 ret
->error
= "Proxy error: Unable to resolve proxy host name";
436 sfree(proxy_canonical_name
);
438 /* create the actual socket we will be using,
439 * connected to our proxy server and port.
441 ret
->sub_socket
= sk_new(proxy_addr
, cfg
->proxy_port
,
443 nodelay
, (Plug
) pplug
);
444 if (sk_socket_error(ret
->sub_socket
) != NULL
)
447 /* start the proxy negotiation process... */
448 sk_set_frozen(ret
->sub_socket
, 0);
449 ret
->negotiate(ret
, PROXY_CHANGE_NEW
);
454 /* no proxy, so just return the direct socket */
455 return sk_new(addr
, port
, privport
, oobinline
, nodelay
, plug
);
458 Socket
new_listener(char *srcaddr
, int port
, Plug plug
, int local_host_only
,
461 /* TODO: SOCKS (and potentially others) support inbound
462 * TODO: connections via the proxy. support them.
465 return sk_newlistener(srcaddr
, port
, plug
, local_host_only
);
468 /* ----------------------------------------------------------------------
469 * HTTP CONNECT proxy type.
472 static int get_line_end (char * data
, int len
)
478 if (data
[off
] == '\n') {
479 /* we have a newline */
482 /* is that the only thing on this line? */
483 if (off
<= 2) return off
;
485 /* if not, then there is the possibility that this header
486 * continues onto the next line, if it starts with a space
491 data
[off
+1] != ' ' &&
492 data
[off
+1] != '\t') return off
;
494 /* the line does continue, so we have to keep going
495 * until we see an the header's "real" end of line.
506 int proxy_http_negotiate (Proxy_Socket p
, int change
)
508 if (p
->state
== PROXY_STATE_NEW
) {
509 /* we are just beginning the proxy negotiate process,
510 * so we'll send off the initial bits of the request.
511 * for this proxy method, it's just a simple HTTP
514 char *buf
, dest
[512];
516 sk_getaddr(p
->remote_addr
, dest
, lenof(dest
));
518 buf
= dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
519 dest
, p
->remote_port
, dest
, p
->remote_port
);
520 sk_write(p
->sub_socket
, buf
, strlen(buf
));
523 if (p
->cfg
.proxy_username
[0] || p
->cfg
.proxy_password
[0]) {
524 char buf
[sizeof(p
->cfg
.proxy_username
)+sizeof(p
->cfg
.proxy_password
)];
525 char buf2
[sizeof(buf
)*4/3 + 100];
527 sprintf(buf
, "%s:%s", p
->cfg
.proxy_username
, p
->cfg
.proxy_password
);
529 sprintf(buf2
, "Proxy-Authorization: Basic ");
530 for (i
= 0, j
= strlen(buf2
); i
< len
; i
+= 3, j
+= 4)
531 base64_encode_atom((unsigned char *)(buf
+i
),
532 (len
-i
> 3 ?
3 : len
-i
), buf2
+j
);
533 strcpy(buf2
+j
, "\r\n");
534 sk_write(p
->sub_socket
, buf2
, strlen(buf2
));
537 sk_write(p
->sub_socket
, "\r\n", 2);
543 if (change
== PROXY_CHANGE_CLOSING
) {
544 /* if our proxy negotiation process involves closing and opening
545 * new sockets, then we would want to intercept this closing
546 * callback when we were expecting it. if we aren't anticipating
547 * a socket close, then some error must have occurred. we'll
548 * just pass those errors up to the backend.
550 return plug_closing(p
->plug
, p
->closing_error_msg
,
551 p
->closing_error_code
,
552 p
->closing_calling_back
);
555 if (change
== PROXY_CHANGE_SENT
) {
556 /* some (or all) of what we wrote to the proxy was sent.
557 * we don't do anything new, however, until we receive the
558 * proxy's response. we might want to set a timer so we can
559 * timeout the proxy negotiation after a while...
564 if (change
== PROXY_CHANGE_ACCEPTING
) {
565 /* we should _never_ see this, as we are using our socket to
566 * connect to a proxy, not accepting inbound connections.
567 * what should we do? close the socket with an appropriate
570 return plug_accepting(p
->plug
, p
->accepting_sock
);
573 if (change
== PROXY_CHANGE_RECEIVE
) {
574 /* we have received data from the underlying socket, which
575 * we'll need to parse, process, and respond to appropriately.
584 int min_ver
, maj_ver
, status
;
586 /* get the status line */
587 len
= bufchain_size(&p
->pending_input_data
);
588 assert(len
> 0); /* or we wouldn't be here */
589 data
= snewn(len
, char);
590 bufchain_fetch(&p
->pending_input_data
, data
, len
);
592 eol
= get_line_end(data
, len
);
599 /* We can't rely on whether the %n incremented the sscanf return */
600 if (sscanf((char *)data
, "HTTP/%i.%i %n",
601 &maj_ver
, &min_ver
, &status
) < 2 || status
== -1) {
602 plug_closing(p
->plug
, "Proxy error: HTTP response was absent",
603 PROXY_ERROR_GENERAL
, 0);
608 /* remove the status line from the input buffer. */
609 bufchain_consume(&p
->pending_input_data
, eol
);
610 if (data
[status
] != '2') {
614 while (eol
> status
&&
615 (data
[eol
-1] == '\r' || data
[eol
-1] == '\n'))
617 buf
= dupprintf("Proxy error: %s", data
+status
);
618 plug_closing(p
->plug
, buf
, PROXY_ERROR_GENERAL
, 0);
631 /* get headers. we're done when we get a
632 * header of length 2, (ie. just "\r\n")
635 len
= bufchain_size(&p
->pending_input_data
);
636 assert(len
> 0); /* or we wouldn't be here */
637 data
= snewn(len
, char);
639 bufchain_fetch(&p
->pending_input_data
, data
, len
);
641 eol
= get_line_end(datap
, len
);
648 bufchain_consume(&p
->pending_input_data
, eol
);
651 eol
= get_line_end(datap
, len
);
656 bufchain_consume(&p
->pending_input_data
, 2);
658 /* proxy activate will have dealt with
659 * whatever is left of the buffer */
669 plug_closing(p
->plug
, "Proxy error: unexpected proxy error",
670 PROXY_ERROR_UNEXPECTED
, 0);
674 /* ----------------------------------------------------------------------
678 /* SOCKS version 4 */
679 int proxy_socks4_negotiate (Proxy_Socket p
, int change
)
681 if (p
->state
== PROXY_CHANGE_NEW
) {
684 * version number (1 byte) = 4
685 * command code (1 byte)
688 * dest. port (2 bytes) [network order]
689 * dest. address (4 bytes)
690 * user ID (variable length, null terminated string)
693 int length
, type
, namelen
;
694 char *command
, addr
[4], hostname
[512];
696 type
= sk_addrtype(p
->remote_addr
);
697 if (type
== ADDRTYPE_IPV6
) {
698 plug_closing(p
->plug
, "Proxy error: SOCKS version 4 does"
699 " not support IPv6", PROXY_ERROR_GENERAL
, 0);
701 } else if (type
== ADDRTYPE_IPV4
) {
703 sk_addrcopy(p
->remote_addr
, addr
);
704 } else { /* type == ADDRTYPE_NAME */
705 assert(type
== ADDRTYPE_NAME
);
706 sk_getaddr(p
->remote_addr
, hostname
, lenof(hostname
));
707 namelen
= strlen(hostname
) + 1; /* include the NUL */
708 addr
[0] = addr
[1] = addr
[2] = 0;
712 length
= strlen(p
->cfg
.proxy_username
) + namelen
+ 9;
713 command
= snewn(length
, char);
714 strcpy(command
+ 8, p
->cfg
.proxy_username
);
716 command
[0] = 4; /* version 4 */
717 command
[1] = 1; /* CONNECT command */
720 command
[2] = (char) (p
->remote_port
>> 8) & 0xff;
721 command
[3] = (char) p
->remote_port
& 0xff;
724 memcpy(command
+ 4, addr
, 4);
727 memcpy(command
+ 8 + strlen(p
->cfg
.proxy_username
) + 1,
730 sk_write(p
->sub_socket
, command
, length
);
737 if (change
== PROXY_CHANGE_CLOSING
) {
738 /* if our proxy negotiation process involves closing and opening
739 * new sockets, then we would want to intercept this closing
740 * callback when we were expecting it. if we aren't anticipating
741 * a socket close, then some error must have occurred. we'll
742 * just pass those errors up to the backend.
744 return plug_closing(p
->plug
, p
->closing_error_msg
,
745 p
->closing_error_code
,
746 p
->closing_calling_back
);
749 if (change
== PROXY_CHANGE_SENT
) {
750 /* some (or all) of what we wrote to the proxy was sent.
751 * we don't do anything new, however, until we receive the
752 * proxy's response. we might want to set a timer so we can
753 * timeout the proxy negotiation after a while...
758 if (change
== PROXY_CHANGE_ACCEPTING
) {
759 /* we should _never_ see this, as we are using our socket to
760 * connect to a proxy, not accepting inbound connections.
761 * what should we do? close the socket with an appropriate
764 return plug_accepting(p
->plug
, p
->accepting_sock
);
767 if (change
== PROXY_CHANGE_RECEIVE
) {
768 /* we have received data from the underlying socket, which
769 * we'll need to parse, process, and respond to appropriately.
774 * version number (1 byte) = 4
775 * reply code (1 byte)
776 * 90 = request granted
777 * 91 = request rejected or failed
778 * 92 = request rejected due to lack of IDENTD on client
779 * 93 = request rejected due to difference in user ID
780 * (what we sent vs. what IDENTD said)
781 * dest. port (2 bytes)
782 * dest. address (4 bytes)
787 if (bufchain_size(&p
->pending_input_data
) < 8)
788 return 1; /* not got anything yet */
790 /* get the response */
791 bufchain_fetch(&p
->pending_input_data
, data
, 8);
794 plug_closing(p
->plug
, "Proxy error: SOCKS proxy responded with "
795 "unexpected reply code version",
796 PROXY_ERROR_GENERAL
, 0);
804 plug_closing(p
->plug
, "Proxy error: SOCKS server wanted IDENTD on client",
805 PROXY_ERROR_GENERAL
, 0);
808 plug_closing(p
->plug
, "Proxy error: Username and IDENTD on client don't agree",
809 PROXY_ERROR_GENERAL
, 0);
813 plug_closing(p
->plug
, "Proxy error: Error while communicating with proxy",
814 PROXY_ERROR_GENERAL
, 0);
820 bufchain_consume(&p
->pending_input_data
, 8);
824 /* proxy activate will have dealt with
825 * whatever is left of the buffer */
830 plug_closing(p
->plug
, "Proxy error: unexpected proxy error",
831 PROXY_ERROR_UNEXPECTED
, 0);
835 /* SOCKS version 5 */
836 int proxy_socks5_negotiate (Proxy_Socket p
, int change
)
838 if (p
->state
== PROXY_CHANGE_NEW
) {
841 * version number (1 byte) = 5
842 * number of available authentication methods (1 byte)
843 * available authentication methods (1 byte * previous value)
844 * authentication methods:
845 * 0x00 = no authentication
847 * 0x02 = username/password
854 command
[0] = 5; /* version 5 */
855 if (p
->cfg
.proxy_username
[0] || p
->cfg
.proxy_password
[0]) {
856 command
[1] = 2; /* two methods supported: */
857 command
[2] = 0x00; /* no authentication */
858 command
[3] = 0x02; /* username/password */
861 command
[1] = 1; /* one methods supported: */
862 command
[2] = 0x00; /* no authentication */
866 sk_write(p
->sub_socket
, command
, len
);
872 if (change
== PROXY_CHANGE_CLOSING
) {
873 /* if our proxy negotiation process involves closing and opening
874 * new sockets, then we would want to intercept this closing
875 * callback when we were expecting it. if we aren't anticipating
876 * a socket close, then some error must have occurred. we'll
877 * just pass those errors up to the backend.
879 return plug_closing(p
->plug
, p
->closing_error_msg
,
880 p
->closing_error_code
,
881 p
->closing_calling_back
);
884 if (change
== PROXY_CHANGE_SENT
) {
885 /* some (or all) of what we wrote to the proxy was sent.
886 * we don't do anything new, however, until we receive the
887 * proxy's response. we might want to set a timer so we can
888 * timeout the proxy negotiation after a while...
893 if (change
== PROXY_CHANGE_ACCEPTING
) {
894 /* we should _never_ see this, as we are using our socket to
895 * connect to a proxy, not accepting inbound connections.
896 * what should we do? close the socket with an appropriate
899 return plug_accepting(p
->plug
, p
->accepting_sock
);
902 if (change
== PROXY_CHANGE_RECEIVE
) {
903 /* we have received data from the underlying socket, which
904 * we'll need to parse, process, and respond to appropriately.
910 * version number (1 byte) = 5
911 * authentication method (1 byte)
912 * authentication methods:
913 * 0x00 = no authentication
915 * 0x02 = username/password
917 * 0xff = no acceptable methods
921 if (bufchain_size(&p
->pending_input_data
) < 2)
922 return 1; /* not got anything yet */
924 /* get the response */
925 bufchain_fetch(&p
->pending_input_data
, data
, 2);
928 plug_closing(p
->plug
, "Proxy error: SOCKS proxy returned unexpected version",
929 PROXY_ERROR_GENERAL
, 0);
933 if (data
[1] == 0x00) p
->state
= 2; /* no authentication needed */
934 else if (data
[1] == 0x01) p
->state
= 4; /* GSSAPI authentication */
935 else if (data
[1] == 0x02) p
->state
= 5; /* username/password authentication */
936 else if (data
[1] == 0x03) p
->state
= 6; /* CHAP authentication */
938 plug_closing(p
->plug
, "Proxy error: SOCKS proxy did not accept our authentication",
939 PROXY_ERROR_GENERAL
, 0);
942 bufchain_consume(&p
->pending_input_data
, 2);
947 /* password authentication reply format:
948 * version number (1 bytes) = 1
949 * reply code (1 byte)
955 if (bufchain_size(&p
->pending_input_data
) < 2)
956 return 1; /* not got anything yet */
958 /* get the response */
959 bufchain_fetch(&p
->pending_input_data
, data
, 2);
962 plug_closing(p
->plug
, "Proxy error: SOCKS password "
963 "subnegotiation contained wrong version number",
964 PROXY_ERROR_GENERAL
, 0);
970 plug_closing(p
->plug
, "Proxy error: SOCKS proxy refused"
971 " password authentication",
972 PROXY_ERROR_GENERAL
, 0);
976 bufchain_consume(&p
->pending_input_data
, 2);
977 p
->state
= 2; /* now proceed as authenticated */
983 * version number (1 byte) = 5
984 * command code (1 byte)
988 * reserved (1 byte) = 0x00
989 * address type (1 byte)
991 * 3 = domainname (first byte has length, no terminating null)
993 * dest. address (variable)
994 * dest. port (2 bytes) [network order]
1001 type
= sk_addrtype(p
->remote_addr
);
1002 if (type
== ADDRTYPE_IPV4
) {
1003 len
= 10; /* 4 hdr + 4 addr + 2 trailer */
1004 command
[3] = 1; /* IPv4 */
1005 sk_addrcopy(p
->remote_addr
, command
+4);
1006 } else if (type
== ADDRTYPE_IPV6
) {
1007 len
= 22; /* 4 hdr + 16 addr + 2 trailer */
1008 command
[3] = 4; /* IPv6 */
1009 sk_addrcopy(p
->remote_addr
, command
+4);
1011 assert(type
== ADDRTYPE_NAME
);
1013 sk_getaddr(p
->remote_addr
, command
+5, 256);
1014 command
[4] = strlen(command
+5);
1015 len
= 7 + command
[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
1018 command
[0] = 5; /* version 5 */
1019 command
[1] = 1; /* CONNECT command */
1023 command
[len
-2] = (char) (p
->remote_port
>> 8) & 0xff;
1024 command
[len
-1] = (char) p
->remote_port
& 0xff;
1026 sk_write(p
->sub_socket
, command
, len
);
1032 if (p
->state
== 3) {
1035 * version number (1 bytes) = 5
1036 * reply code (1 byte)
1038 * 1 = general SOCKS server failure
1039 * 2 = connection not allowed by ruleset
1040 * 3 = network unreachable
1041 * 4 = host unreachable
1042 * 5 = connection refused
1044 * 7 = command not supported
1045 * 8 = address type not supported
1046 * reserved (1 byte) = x00
1047 * address type (1 byte)
1049 * 3 = domainname (first byte has length, no terminating null)
1051 * server bound address (variable)
1052 * server bound port (2 bytes) [network order]
1057 /* First 5 bytes of packet are enough to tell its length. */
1058 if (bufchain_size(&p
->pending_input_data
) < 5)
1059 return 1; /* not got anything yet */
1061 /* get the response */
1062 bufchain_fetch(&p
->pending_input_data
, data
, 5);
1065 plug_closing(p
->plug
, "Proxy error: SOCKS proxy returned wrong version number",
1066 PROXY_ERROR_GENERAL
, 0);
1073 strcpy(buf
, "Proxy error: ");
1076 case 1: strcat(buf
, "General SOCKS server failure"); break;
1077 case 2: strcat(buf
, "Connection not allowed by ruleset"); break;
1078 case 3: strcat(buf
, "Network unreachable"); break;
1079 case 4: strcat(buf
, "Host unreachable"); break;
1080 case 5: strcat(buf
, "Connection refused"); break;
1081 case 6: strcat(buf
, "TTL expired"); break;
1082 case 7: strcat(buf
, "Command not supported"); break;
1083 case 8: strcat(buf
, "Address type not supported"); break;
1084 default: sprintf(buf
+strlen(buf
),
1085 "Unrecognised SOCKS error code %d",
1089 plug_closing(p
->plug
, buf
, PROXY_ERROR_GENERAL
, 0);
1095 * Eat the rest of the reply packet.
1097 len
= 6; /* first 4 bytes, last 2 */
1099 case 1: len
+= 4; break; /* IPv4 address */
1100 case 4: len
+= 16; break;/* IPv6 address */
1101 case 3: len
+= (unsigned char)data
[4]; break; /* domain name */
1103 plug_closing(p
->plug
, "Proxy error: SOCKS proxy returned "
1104 "unrecognised address format",
1105 PROXY_ERROR_GENERAL
, 0);
1108 if (bufchain_size(&p
->pending_input_data
) < len
)
1109 return 1; /* not got whole reply yet */
1110 bufchain_consume(&p
->pending_input_data
, len
);
1117 if (p
->state
== 4) {
1118 /* TODO: Handle GSSAPI authentication */
1119 plug_closing(p
->plug
, "Proxy error: We don't support GSSAPI authentication",
1120 PROXY_ERROR_GENERAL
, 0);
1124 if (p
->state
== 5) {
1125 if (p
->cfg
.proxy_username
[0] || p
->cfg
.proxy_password
[0]) {
1126 char userpwbuf
[514];
1128 ulen
= strlen(p
->cfg
.proxy_username
);
1129 if (ulen
> 255) ulen
= 255; if (ulen
< 1) ulen
= 1;
1130 plen
= strlen(p
->cfg
.proxy_password
);
1131 if (plen
> 255) plen
= 255; if (plen
< 1) plen
= 1;
1132 userpwbuf
[0] = 1; /* version number of subnegotiation */
1133 userpwbuf
[1] = ulen
;
1134 memcpy(userpwbuf
+2, p
->cfg
.proxy_username
, ulen
);
1135 userpwbuf
[ulen
+2] = plen
;
1136 memcpy(userpwbuf
+ulen
+3, p
->cfg
.proxy_password
, plen
);
1137 sk_write(p
->sub_socket
, userpwbuf
, ulen
+ plen
+ 3);
1140 plug_closing(p
->plug
, "Proxy error: Server chose "
1141 "username/password authentication but we "
1143 PROXY_ERROR_GENERAL
, 0);
1147 if (p
->state
== 6) {
1148 /* TODO: Handle CHAP authentication */
1149 plug_closing(p
->plug
, "Proxy error: We don't support CHAP authentication",
1150 PROXY_ERROR_GENERAL
, 0);
1156 plug_closing(p
->plug
, "Proxy error: Unexpected proxy error",
1157 PROXY_ERROR_UNEXPECTED
, 0);
1161 /* ----------------------------------------------------------------------
1162 * `Telnet' proxy type.
1164 * (This is for ad-hoc proxies where you connect to the proxy's
1165 * telnet port and send a command such as `connect host port'. The
1166 * command is configurable, since this proxy type is typically not
1167 * standardised or at all well-defined.)
1170 char *format_telnet_command(SockAddr addr
, int port
, const Config
*cfg
)
1173 int retlen
= 0, retsize
= 0;
1175 #define ENSURE(n) do { \
1176 if (retsize < retlen + n) { \
1177 retsize = retlen + n + 512; \
1178 ret = sresize(ret, retsize, char); \
1182 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
1183 * %%, %host, %port, %user, and %pass
1186 while (cfg
->proxy_telnet_command
[eo
] != 0) {
1188 /* scan forward until we hit end-of-line,
1189 * or an escape character (\ or %) */
1190 while (cfg
->proxy_telnet_command
[eo
] != 0 &&
1191 cfg
->proxy_telnet_command
[eo
] != '%' &&
1192 cfg
->proxy_telnet_command
[eo
] != '\\') eo
++;
1194 /* if we hit eol, break out of our escaping loop */
1195 if (cfg
->proxy_telnet_command
[eo
] == 0) break;
1197 /* if there was any unescaped text before the escape
1198 * character, send that now */
1201 memcpy(ret
+ retlen
, cfg
->proxy_telnet_command
+ so
, eo
- so
);
1207 /* if the escape character was the last character of
1208 * the line, we'll just stop and send it. */
1209 if (cfg
->proxy_telnet_command
[eo
] == 0) break;
1211 if (cfg
->proxy_telnet_command
[so
] == '\\') {
1213 /* we recognize \\, \%, \r, \n, \t, \x??.
1214 * anything else, we just send unescaped (including the \).
1217 switch (cfg
->proxy_telnet_command
[eo
]) {
1221 ret
[retlen
++] = '\\';
1227 ret
[retlen
++] = '%';
1233 ret
[retlen
++] = '\r';
1239 ret
[retlen
++] = '\n';
1245 ret
[retlen
++] = '\t';
1252 /* escaped hexadecimal value (ie. \xff) */
1253 unsigned char v
= 0;
1258 if (cfg
->proxy_telnet_command
[eo
] >= '0' &&
1259 cfg
->proxy_telnet_command
[eo
] <= '9')
1260 v
+= cfg
->proxy_telnet_command
[eo
] - '0';
1261 else if (cfg
->proxy_telnet_command
[eo
] >= 'a' &&
1262 cfg
->proxy_telnet_command
[eo
] <= 'f')
1263 v
+= cfg
->proxy_telnet_command
[eo
] - 'a' + 10;
1264 else if (cfg
->proxy_telnet_command
[eo
] >= 'A' &&
1265 cfg
->proxy_telnet_command
[eo
] <= 'F')
1266 v
+= cfg
->proxy_telnet_command
[eo
] - 'A' + 10;
1268 /* non hex character, so we abort and just
1269 * send the whole thing unescaped (including \x)
1272 ret
[retlen
++] = '\\';
1277 /* we only extract two hex characters */
1293 memcpy(ret
+retlen
, cfg
->proxy_telnet_command
+ so
, 2);
1300 /* % escape. we recognize %%, %host, %port, %user, %pass.
1301 * anything else, we just send unescaped (including the %).
1304 if (cfg
->proxy_telnet_command
[eo
] == '%') {
1306 ret
[retlen
++] = '%';
1309 else if (strnicmp(cfg
->proxy_telnet_command
+ eo
,
1313 sk_getaddr(addr
, dest
, lenof(dest
));
1314 destlen
= strlen(dest
);
1316 memcpy(ret
+retlen
, dest
, destlen
);
1320 else if (strnicmp(cfg
->proxy_telnet_command
+ eo
,
1322 char portstr
[8], portlen
;
1323 portlen
= sprintf(portstr
, "%i", port
);
1325 memcpy(ret
+ retlen
, portstr
, portlen
);
1329 else if (strnicmp(cfg
->proxy_telnet_command
+ eo
,
1331 int userlen
= strlen(cfg
->proxy_username
);
1333 memcpy(ret
+retlen
, cfg
->proxy_username
, userlen
);
1337 else if (strnicmp(cfg
->proxy_telnet_command
+ eo
,
1339 int passlen
= strlen(cfg
->proxy_password
);
1341 memcpy(ret
+retlen
, cfg
->proxy_password
, passlen
);
1346 /* we don't escape this, so send the % now, and
1347 * don't advance eo, so that we'll consider the
1348 * text immediately following the % as unescaped.
1351 ret
[retlen
++] = '%';
1355 /* resume scanning for additional escapes after this one. */
1359 /* if there is any unescaped text at the end of the line, send it */
1362 memcpy(ret
+ retlen
, cfg
->proxy_telnet_command
+ so
, eo
- so
);
1373 int proxy_telnet_negotiate (Proxy_Socket p
, int change
)
1375 if (p
->state
== PROXY_CHANGE_NEW
) {
1376 char *formatted_cmd
;
1378 formatted_cmd
= format_telnet_command(p
->remote_addr
, p
->remote_port
,
1381 sk_write(p
->sub_socket
, formatted_cmd
, strlen(formatted_cmd
));
1382 sfree(formatted_cmd
);
1388 if (change
== PROXY_CHANGE_CLOSING
) {
1389 /* if our proxy negotiation process involves closing and opening
1390 * new sockets, then we would want to intercept this closing
1391 * callback when we were expecting it. if we aren't anticipating
1392 * a socket close, then some error must have occurred. we'll
1393 * just pass those errors up to the backend.
1395 return plug_closing(p
->plug
, p
->closing_error_msg
,
1396 p
->closing_error_code
,
1397 p
->closing_calling_back
);
1400 if (change
== PROXY_CHANGE_SENT
) {
1401 /* some (or all) of what we wrote to the proxy was sent.
1402 * we don't do anything new, however, until we receive the
1403 * proxy's response. we might want to set a timer so we can
1404 * timeout the proxy negotiation after a while...
1409 if (change
== PROXY_CHANGE_ACCEPTING
) {
1410 /* we should _never_ see this, as we are using our socket to
1411 * connect to a proxy, not accepting inbound connections.
1412 * what should we do? close the socket with an appropriate
1415 return plug_accepting(p
->plug
, p
->accepting_sock
);
1418 if (change
== PROXY_CHANGE_RECEIVE
) {
1419 /* we have received data from the underlying socket, which
1420 * we'll need to parse, process, and respond to appropriately.
1425 /* proxy activate will have dealt with
1426 * whatever is left of the buffer */
1430 plug_closing(p
->plug
, "Proxy error: Unexpected proxy error",
1431 PROXY_ERROR_UNEXPECTED
, 0);