2 * Network proxy abstraction in PuTTY
4 * A proxy layer, if necessary, wedges itself between the network
5 * code and the higher level backend.
10 #define DEFINE_PLUG_METHOD_MACROS
16 * Call this when proxy negotiation is complete, so that this
17 * socket can begin working normally.
19 void proxy_activate (Proxy_Socket p)
24 p->state = PROXY_STATE_ACTIVE;
26 /* let's try to keep extra receive events from coming through */
27 sk_set_frozen(p->sub_socket, 1);
29 /* send buffered OOB writes */
30 while (bufchain_size(&p->pending_oob_output_data) > 0) {
31 bufchain_prefix(&p->pending_oob_output_data, &data, &len);
32 sk_write_oob(p->sub_socket, data, len);
33 bufchain_consume(&p->pending_oob_output_data, len);
35 bufchain_clear(&p->pending_oob_output_data);
37 /* send buffered normal writes */
38 while (bufchain_size(&p->pending_output_data) > 0) {
39 bufchain_prefix(&p->pending_output_data, &data, &len);
40 sk_write(p->sub_socket, data, len);
41 bufchain_consume(&p->pending_output_data, len);
43 bufchain_clear(&p->pending_output_data);
45 /* if we were asked to flush the output during
46 * the proxy negotiation process, do so now.
48 if (p->pending_flush) sk_flush(p->sub_socket);
50 /* forward buffered recv data to the backend */
51 while (bufchain_size(&p->pending_input_data) > 0) {
52 bufchain_prefix(&p->pending_input_data, &data, &len);
53 plug_receive(p->plug, 0, data, len);
54 bufchain_consume(&p->pending_input_data, len);
56 bufchain_clear(&p->pending_input_data);
58 /* now set the underlying socket to whatever freeze state they wanted */
59 sk_set_frozen(p->sub_socket, p->freeze);
62 /* basic proxy socket functions */
64 static Plug sk_proxy_plug (Socket s, Plug p)
66 Proxy_Socket ps = (Proxy_Socket) s;
73 static void sk_proxy_close (Socket s)
75 Proxy_Socket ps = (Proxy_Socket) s;
77 sk_close(ps->sub_socket);
81 static int sk_proxy_write (Socket s, char *data, int len)
83 Proxy_Socket ps = (Proxy_Socket) s;
85 if (ps->state != PROXY_STATE_ACTIVE) {
86 bufchain_add(&ps->pending_output_data, data, len);
87 return bufchain_size(&ps->pending_output_data);
89 return sk_write(ps->sub_socket, data, len);
92 static int sk_proxy_write_oob (Socket s, char *data, int len)
94 Proxy_Socket ps = (Proxy_Socket) s;
96 if (ps->state != PROXY_STATE_ACTIVE) {
97 bufchain_clear(&ps->pending_output_data);
98 bufchain_clear(&ps->pending_oob_output_data);
99 bufchain_add(&ps->pending_oob_output_data, data, len);
102 return sk_write_oob(ps->sub_socket, data, len);
105 static void sk_proxy_flush (Socket s)
107 Proxy_Socket ps = (Proxy_Socket) s;
109 if (ps->state != PROXY_STATE_ACTIVE) {
110 ps->pending_flush = 1;
113 sk_flush(ps->sub_socket);
116 static void sk_proxy_set_private_ptr (Socket s, void *ptr)
118 Proxy_Socket ps = (Proxy_Socket) s;
119 sk_set_private_ptr(ps->sub_socket, ptr);
122 static void * sk_proxy_get_private_ptr (Socket s)
124 Proxy_Socket ps = (Proxy_Socket) s;
125 return sk_get_private_ptr(ps->sub_socket);
128 static void sk_proxy_set_frozen (Socket s, int is_frozen)
130 Proxy_Socket ps = (Proxy_Socket) s;
132 if (ps->state != PROXY_STATE_ACTIVE) {
133 ps->freeze = is_frozen;
136 sk_set_frozen(ps->sub_socket, is_frozen);
139 static char * sk_proxy_socket_error (Socket s)
141 Proxy_Socket ps = (Proxy_Socket) s;
142 if (ps->error != NULL || ps->sub_socket == NULL) {
145 return sk_socket_error(ps->sub_socket);
148 /* basic proxy plug functions */
150 static int plug_proxy_closing (Plug p, char *error_msg,
151 int error_code, int calling_back)
153 Proxy_Plug pp = (Proxy_Plug) p;
154 Proxy_Socket ps = pp->proxy_socket;
156 if (ps->state != PROXY_STATE_ACTIVE) {
157 ps->closing_error_msg = error_msg;
158 ps->closing_error_code = error_code;
159 ps->closing_calling_back = calling_back;
160 return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
162 return plug_closing(ps->plug, error_msg,
163 error_code, calling_back);
166 static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
168 Proxy_Plug pp = (Proxy_Plug) p;
169 Proxy_Socket ps = pp->proxy_socket;
171 if (ps->state != PROXY_STATE_ACTIVE) {
172 /* we will lose the urgentness of this data, but since most,
173 * if not all, of this data will be consumed by the negotiation
174 * process, hopefully it won't affect the protocol above us
176 bufchain_add(&ps->pending_input_data, data, len);
177 ps->receive_urgent = urgent;
178 ps->receive_data = data;
179 ps->receive_len = len;
180 return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
182 return plug_receive(ps->plug, urgent, data, len);
185 static void plug_proxy_sent (Plug p, int bufsize)
187 Proxy_Plug pp = (Proxy_Plug) p;
188 Proxy_Socket ps = pp->proxy_socket;
190 if (ps->state != PROXY_STATE_ACTIVE) {
191 ps->sent_bufsize = bufsize;
192 ps->negotiate(ps, PROXY_CHANGE_SENT);
195 plug_sent(ps->plug, bufsize);
198 static int plug_proxy_accepting (Plug p, void *sock)
200 Proxy_Plug pp = (Proxy_Plug) p;
201 Proxy_Socket ps = pp->proxy_socket;
203 if (ps->state != PROXY_STATE_ACTIVE) {
204 ps->accepting_sock = sock;
205 return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
207 return plug_accepting(ps->plug, sock);
210 static int proxy_for_destination (SockAddr addr, char * hostname, int port)
214 int hostip_len, hostname_len;
217 /* we want a string representation of the IP address for comparisons */
218 sk_getaddr(addr, hostip, 64);
220 hostip_len = strlen(hostip);
221 hostname_len = strlen(hostname);
223 exclude_list = cfg.proxy_exclude_list;
225 /* now parse the exclude list, and see if either our IP
226 * or hostname matches anything in it.
229 while (exclude_list[s]) {
230 while (exclude_list[s] &&
231 (isspace(exclude_list[s]) ||
232 exclude_list[s] == ',')) s++;
234 if (!exclude_list[s]) break;
238 while (exclude_list[e] &&
239 (isalnum(exclude_list[e]) ||
240 exclude_list[e] == '-' ||
241 exclude_list[e] == '.' ||
242 exclude_list[e] == '*')) e++;
244 if (exclude_list[s] == '*') {
245 /* wildcard at beginning of entry */
247 if (strnicmp(hostip + hostip_len - (e - s - 1),
248 exclude_list + s + 1, e - s - 1) == 0 ||
249 strnicmp(hostname + hostname_len - (e - s - 1),
250 exclude_list + s + 1, e - s - 1) == 0)
251 return 0; /* IP/hostname range excluded. do not use proxy. */
253 } else if (exclude_list[e-1] == '*') {
254 /* wildcard at end of entry */
256 if (strnicmp(hostip, exclude_list + s, e - s - 1) == 0 ||
257 strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
258 return 0; /* IP/hostname range excluded. do not use proxy. */
261 /* no wildcard at either end, so let's try an absolute
262 * match (ie. a specific IP)
265 if (stricmp(hostip, exclude_list + s) == 0)
266 return 0; /* IP/hostname excluded. do not use proxy. */
267 if (stricmp(hostname, exclude_list + s) == 0)
268 return 0; /* IP/hostname excluded. do not use proxy. */
274 /* no matches in the exclude list, so use the proxy */
278 Socket new_connection(SockAddr addr, char *hostname,
279 int port, int privport,
280 int oobinline, int nodelay, Plug plug)
282 static struct socket_function_table socket_fn_table = {
288 sk_proxy_set_private_ptr,
289 sk_proxy_get_private_ptr,
291 sk_proxy_socket_error
294 static struct plug_function_table plug_fn_table = {
301 if (cfg.proxy_type != PROXY_NONE &&
302 proxy_for_destination(addr, hostname, port))
307 char * proxy_canonical_name;
309 ret = smalloc(sizeof(struct Socket_proxy_tag));
310 ret->fn = &socket_fn_table;
312 ret->remote_addr = addr;
313 ret->remote_port = port;
315 bufchain_init(&ret->pending_input_data);
316 bufchain_init(&ret->pending_output_data);
317 bufchain_init(&ret->pending_oob_output_data);
319 ret->sub_socket = NULL;
320 ret->state = PROXY_STATE_NEW;
322 if (cfg.proxy_type == PROXY_HTTP) {
323 ret->negotiate = proxy_http_negotiate;
324 } else if (cfg.proxy_type == PROXY_SOCKS) {
325 ret->negotiate = proxy_socks_negotiate;
326 } else if (cfg.proxy_type == PROXY_TELNET) {
327 ret->negotiate = proxy_telnet_negotiate;
329 ret->error = "Network error: Unknown proxy method";
333 /* create the proxy plug to map calls from the actual
334 * socket into our proxy socket layer */
335 pplug = smalloc(sizeof(struct Plug_proxy_tag));
336 pplug->fn = &plug_fn_table;
337 pplug->proxy_socket = ret;
340 proxy_addr = sk_namelookup(cfg.proxy_host,
341 &proxy_canonical_name);
342 sfree(proxy_canonical_name);
344 /* create the actual socket we will be using,
345 * connected to our proxy server and port.
347 ret->sub_socket = sk_new(proxy_addr, cfg.proxy_port,
349 nodelay, (Plug) pplug);
350 if (sk_socket_error(ret->sub_socket) != NULL)
353 sk_addr_free(proxy_addr);
355 /* start the proxy negotiation process... */
356 sk_set_frozen(ret->sub_socket, 0);
357 ret->negotiate(ret, PROXY_CHANGE_NEW);
362 /* no proxy, so just return the direct socket */
363 return sk_new(addr, port, privport, oobinline, nodelay, plug);
366 Socket new_listener(int port, Plug plug, int local_host_only)
368 /* TODO: SOCKS (and potentially others) support inbound
369 * TODO: connections via the proxy. support them.
372 return sk_newlistener(port, plug, local_host_only);
375 /* ----------------------------------------------------------------------
376 * HTTP CONNECT proxy type.
379 static int get_line_end (char * data, int len)
385 if (data[off] == '\n') {
386 /* we have a newline */
389 /* is that the only thing on this line? */
390 if (off <= 2) return off;
392 /* if not, then there is the possibility that this header
393 * continues onto the next line, if it starts with a space
398 data[off+1] != ' ' &&
399 data[off+1] != '\t') return off;
401 /* the line does continue, so we have to keep going
402 * until we see an the header's "real" end of line.
413 int proxy_http_negotiate (Proxy_Socket p, int change)
415 if (p->state == PROXY_STATE_NEW) {
416 /* we are just beginning the proxy negotiate process,
417 * so we'll send off the initial bits of the request.
418 * for this proxy method, it's just a simple HTTP
421 char buf[256], dest[64];
423 sk_getaddr(p->remote_addr, dest, 64);
425 sprintf(buf, "CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n\r\n",
426 dest, p->remote_port, dest, p->remote_port);
427 sk_write(p->sub_socket, buf, strlen(buf));
434 if (change == PROXY_CHANGE_CLOSING) {
435 /* if our proxy negotiation process involves closing and opening
436 * new sockets, then we would want to intercept this closing
437 * callback when we were expecting it. if we aren't anticipating
438 * a socket close, then some error must have occurred. we'll
439 * just pass those errors up to the backend.
441 return plug_closing(p->plug, p->closing_error_msg,
442 p->closing_error_code,
443 p->closing_calling_back);
446 if (change == PROXY_CHANGE_SENT) {
447 /* some (or all) of what we wrote to the proxy was sent.
448 * we don't do anything new, however, until we receive the
449 * proxy's response. we might want to set a timer so we can
450 * timeout the proxy negotiation after a while...
455 if (change == PROXY_CHANGE_ACCEPTING) {
456 /* we should _never_ see this, as we are using our socket to
457 * connect to a proxy, not accepting inbound connections.
458 * what should we do? close the socket with an appropriate
461 return plug_accepting(p->plug, p->accepting_sock);
464 if (change == PROXY_CHANGE_RECEIVE) {
465 /* we have received data from the underlying socket, which
466 * we'll need to parse, process, and respond to appropriately.
475 int min_ver, maj_ver, status;
477 /* get the status line */
478 bufchain_prefix(&p->pending_input_data, &data, &len);
479 eol = get_line_end(data, len);
480 if (eol < 0) return 1;
482 sscanf((char *)data, "HTTP/%i.%i %i", &maj_ver, &min_ver, &status);
484 /* remove the status line from the input buffer. */
485 bufchain_consume(&p->pending_input_data, eol);
487 /* TODO: we need to support Proxy-Auth headers */
489 if (status < 200 || status > 299) {
491 /* TODO: return a more specific error message,
492 * TODO: based on the status code.
494 plug_closing(p->plug, "Network error: Error while communicating with proxy",
495 PROXY_ERROR_GENERAL, 0);
504 /* get headers. we're done when we get a
505 * header of length 2, (ie. just "\r\n")
508 bufchain_prefix(&p->pending_input_data, &data, &len);
509 eol = get_line_end(data, len);
512 /* TODO: Proxy-Auth stuff. in some cases, we will
513 * TODO: need to extract information from headers.
515 bufchain_consume(&p->pending_input_data, eol);
516 bufchain_prefix(&p->pending_input_data, &data, &len);
517 eol = get_line_end(data, len);
522 bufchain_consume(&p->pending_input_data, 2);
524 /* proxy activate will have dealt with
525 * whatever is left of the buffer */
533 plug_closing(p->plug, "Network error: Unexpected proxy error",
534 PROXY_ERROR_UNEXPECTED, 0);
538 /* ----------------------------------------------------------------------
539 * SOCKS proxy type (as yet unimplemented).
542 int proxy_socks_negotiate (Proxy_Socket p, int change)
544 p->error = "Network error: SOCKS proxy implementation is incomplete";
548 /* ----------------------------------------------------------------------
549 * `Telnet' proxy type.
551 * (This is for ad-hoc proxies where you connect to the proxy's
552 * telnet port and send a command such as `connect host port'. The
553 * command is configurable, since this proxy type is typically not
554 * standardised or at all well-defined.)
557 int proxy_telnet_negotiate (Proxy_Socket p, int change)
559 if (p->state == PROXY_CHANGE_NEW) {
563 /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
564 * %%, %host, and %port
567 while (cfg.proxy_telnet_command[eo] != 0) {
569 /* scan forward until we hit end-of-line,
570 * or an escape character (\ or %) */
571 while (cfg.proxy_telnet_command[eo] != 0 &&
572 cfg.proxy_telnet_command[eo] != '%' &&
573 cfg.proxy_telnet_command[eo] != '\\') eo++;
575 /* if we hit eol, break out of our escaping loop */
576 if (cfg.proxy_telnet_command[eo] == 0) break;
578 /* if there was any unescaped text before the escape
579 * character, send that now */
581 sk_write(p->sub_socket,
582 cfg.proxy_telnet_command + so, eo - so);
587 /* if the escape character was the last character of
588 * the line, we'll just stop and send it. */
589 if (cfg.proxy_telnet_command[eo] == 0) break;
591 if (cfg.proxy_telnet_command[so] == '\\') {
593 /* we recognize \\, \%, \r, \n, \t, \x??.
594 * anything else, we just send unescaped (including the \).
597 switch (cfg.proxy_telnet_command[eo]) {
600 sk_write(p->sub_socket, "\\", 1);
605 sk_write(p->sub_socket, "%%", 1);
610 sk_write(p->sub_socket, "\r", 1);
615 sk_write(p->sub_socket, "\n", 1);
620 sk_write(p->sub_socket, "\t", 1);
627 /* escaped hexadecimal value (ie. \xff) */
633 if (cfg.proxy_telnet_command[eo] >= '0' &&
634 cfg.proxy_telnet_command[eo] <= '9')
635 v += cfg.proxy_telnet_command[eo] - '0';
636 else if (cfg.proxy_telnet_command[eo] >= 'a' &&
637 cfg.proxy_telnet_command[eo] <= 'f')
638 v += cfg.proxy_telnet_command[eo] - 'a' + 10;
639 else if (cfg.proxy_telnet_command[eo] >= 'A' &&
640 cfg.proxy_telnet_command[eo] <= 'F')
641 v += cfg.proxy_telnet_command[eo] - 'A' + 10;
643 /* non hex character, so we abort and just
644 * send the whole thing unescaped (including \x)
646 sk_write(p->sub_socket, "\\", 1);
651 /* we only extract two hex characters */
653 sk_write(p->sub_socket, &v, 1);
665 sk_write(p->sub_socket,
666 cfg.proxy_telnet_command + so, 2);
672 /* % escape. we recognize %%, %host, %port. anything else,
673 * we just send unescaped (including the %). */
675 if (cfg.proxy_telnet_command[eo] == '%') {
676 sk_write(p->sub_socket, "%", 1);
679 else if (strnicmp(cfg.proxy_telnet_command + eo,
682 sk_getaddr(p->remote_addr, dest, 64);
683 sk_write(p->sub_socket, dest, strlen(dest));
686 else if (strnicmp(cfg.proxy_telnet_command + eo,
689 sprintf(port, "%i", p->remote_port);
690 sk_write(p->sub_socket, port, strlen(port));
694 /* we don't escape this, so send the % now, and
695 * don't advance eo, so that we'll consider the
696 * text immediately following the % as unescaped.
698 sk_write(p->sub_socket, "%", 1);
702 /* resume scanning for additional escapes after this one. */
706 /* if there is any unescaped text at the end of the line, send it */
708 sk_write(p->sub_socket, cfg.proxy_telnet_command + so, eo - so);
716 if (change == PROXY_CHANGE_CLOSING) {
717 /* if our proxy negotiation process involves closing and opening
718 * new sockets, then we would want to intercept this closing
719 * callback when we were expecting it. if we aren't anticipating
720 * a socket close, then some error must have occurred. we'll
721 * just pass those errors up to the backend.
723 return plug_closing(p->plug, p->closing_error_msg,
724 p->closing_error_code,
725 p->closing_calling_back);
728 if (change == PROXY_CHANGE_SENT) {
729 /* some (or all) of what we wrote to the proxy was sent.
730 * we don't do anything new, however, until we receive the
731 * proxy's response. we might want to set a timer so we can
732 * timeout the proxy negotiation after a while...
737 if (change == PROXY_CHANGE_ACCEPTING) {
738 /* we should _never_ see this, as we are using our socket to
739 * connect to a proxy, not accepting inbound connections.
740 * what should we do? close the socket with an appropriate
743 return plug_accepting(p->plug, p->accepting_sock);
746 if (change == PROXY_CHANGE_RECEIVE) {
747 /* we have received data from the underlying socket, which
748 * we'll need to parse, process, and respond to appropriately.
753 /* proxy activate will have dealt with
754 * whatever is left of the buffer */
758 plug_closing(p->plug, "Network error: Unexpected proxy error",
759 PROXY_ERROR_UNEXPECTED, 0);