-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathproxy.c
1535 lines (1300 loc) · 43.8 KB
/
proxy.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Network proxy abstraction in PuTTY
*
* A proxy layer, if necessary, wedges itself between the network
* code and the higher level backend.
*/
#include <assert.h>
#include <ctype.h>
#include <string.h>
#include "putty.h"
#include "network.h"
#include "proxy.h"
#define do_proxy_dns(conf) \
(conf_get_int(conf, CONF_proxy_dns) == FORCE_ON || \
(conf_get_int(conf, CONF_proxy_dns) == AUTO && \
conf_get_int(conf, CONF_proxy_type) != PROXY_SOCKS4))
/*
* Call this when proxy negotiation is complete, so that this
* socket can begin working normally.
*/
void proxy_activate (ProxySocket *p)
{
size_t output_before, output_after;
p->state = PROXY_STATE_ACTIVE;
/* we want to ignore new receive events until we have sent
* all of our buffered receive data.
*/
sk_set_frozen(p->sub_socket, true);
/* how many bytes of output have we buffered? */
output_before = bufchain_size(&p->pending_oob_output_data) +
bufchain_size(&p->pending_output_data);
/* and keep track of how many bytes do not get sent. */
output_after = 0;
/* send buffered OOB writes */
while (bufchain_size(&p->pending_oob_output_data) > 0) {
ptrlen data = bufchain_prefix(&p->pending_oob_output_data);
output_after += sk_write_oob(p->sub_socket, data.ptr, data.len);
bufchain_consume(&p->pending_oob_output_data, data.len);
}
/* send buffered normal writes */
while (bufchain_size(&p->pending_output_data) > 0) {
ptrlen data = bufchain_prefix(&p->pending_output_data);
output_after += sk_write(p->sub_socket, data.ptr, data.len);
bufchain_consume(&p->pending_output_data, data.len);
}
/* if we managed to send any data, let the higher levels know. */
if (output_after < output_before)
plug_sent(p->plug, output_after);
/* if we were asked to flush the output during
* the proxy negotiation process, do so now.
*/
if (p->pending_flush) sk_flush(p->sub_socket);
/* if we have a pending EOF to send, send it */
if (p->pending_eof) sk_write_eof(p->sub_socket);
/* if the backend wanted the socket unfrozen, try to unfreeze.
* our set_frozen handler will flush buffered receive data before
* unfreezing the actual underlying socket.
*/
if (!p->freeze)
sk_set_frozen(&p->sock, 0);
}
/* basic proxy socket functions */
static Plug *sk_proxy_plug (Socket *s, Plug *p)
{
ProxySocket *ps = container_of(s, ProxySocket, sock);
Plug *ret = ps->plug;
if (p)
ps->plug = p;
return ret;
}
static void sk_proxy_close (Socket *s)
{
ProxySocket *ps = container_of(s, ProxySocket, sock);
sk_close(ps->sub_socket);
sk_addr_free(ps->remote_addr);
sfree(ps);
}
static size_t sk_proxy_write (Socket *s, const void *data, size_t len)
{
ProxySocket *ps = container_of(s, ProxySocket, sock);
if (ps->state != PROXY_STATE_ACTIVE) {
bufchain_add(&ps->pending_output_data, data, len);
return bufchain_size(&ps->pending_output_data);
}
return sk_write(ps->sub_socket, data, len);
}
static size_t sk_proxy_write_oob (Socket *s, const void *data, size_t len)
{
ProxySocket *ps = container_of(s, ProxySocket, sock);
if (ps->state != PROXY_STATE_ACTIVE) {
bufchain_clear(&ps->pending_output_data);
bufchain_clear(&ps->pending_oob_output_data);
bufchain_add(&ps->pending_oob_output_data, data, len);
return len;
}
return sk_write_oob(ps->sub_socket, data, len);
}
static void sk_proxy_write_eof (Socket *s)
{
ProxySocket *ps = container_of(s, ProxySocket, sock);
if (ps->state != PROXY_STATE_ACTIVE) {
ps->pending_eof = true;
return;
}
sk_write_eof(ps->sub_socket);
}
static void sk_proxy_flush (Socket *s)
{
ProxySocket *ps = container_of(s, ProxySocket, sock);
if (ps->state != PROXY_STATE_ACTIVE) {
ps->pending_flush = true;
return;
}
sk_flush(ps->sub_socket);
}
static void sk_proxy_set_frozen (Socket *s, bool is_frozen)
{
ProxySocket *ps = container_of(s, ProxySocket, sock);
if (ps->state != PROXY_STATE_ACTIVE) {
ps->freeze = is_frozen;
return;
}
/* handle any remaining buffered recv data first */
if (bufchain_size(&ps->pending_input_data) > 0) {
ps->freeze = is_frozen;
/* loop while we still have buffered data, and while we are
* unfrozen. the plug_receive call in the loop could result
* in a call back into this function refreezing the socket,
* so we have to check each time.
*/
while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
char databuf[512];
ptrlen data = bufchain_prefix(&ps->pending_input_data);
if (data.len > lenof(databuf))
data.len = lenof(databuf);
memcpy(databuf, data.ptr, data.len);
bufchain_consume(&ps->pending_input_data, data.len);
plug_receive(ps->plug, 0, databuf, data.len);
}
/* if we're still frozen, we'll have to wait for another
* call from the backend to finish unbuffering the data.
*/
if (ps->freeze) return;
}
sk_set_frozen(ps->sub_socket, is_frozen);
}
static const char * sk_proxy_socket_error (Socket *s)
{
ProxySocket *ps = container_of(s, ProxySocket, sock);
if (ps->error != NULL || ps->sub_socket == NULL) {
return ps->error;
}
return sk_socket_error(ps->sub_socket);
}
/* basic proxy plug functions */
static void plug_proxy_log(Plug *plug, int type, SockAddr *addr, int port,
const char *error_msg, int error_code)
{
ProxySocket *ps = container_of(plug, ProxySocket, plugimpl);
plug_log(ps->plug, type, addr, port, error_msg, error_code);
}
static void plug_proxy_closing (Plug *p, const char *error_msg,
int error_code, bool calling_back)
{
ProxySocket *ps = container_of(p, ProxySocket, plugimpl);
if (ps->state != PROXY_STATE_ACTIVE) {
ps->closing_error_msg = error_msg;
ps->closing_error_code = error_code;
ps->closing_calling_back = calling_back;
ps->negotiate(ps, PROXY_CHANGE_CLOSING);
} else {
plug_closing(ps->plug, error_msg, error_code, calling_back);
}
}
static void plug_proxy_receive(
Plug *p, int urgent, const char *data, size_t len)
{
ProxySocket *ps = container_of(p, ProxySocket, plugimpl);
if (ps->state != PROXY_STATE_ACTIVE) {
/* we will lose the urgentness of this data, but since most,
* if not all, of this data will be consumed by the negotiation
* process, hopefully it won't affect the protocol above us
*/
bufchain_add(&ps->pending_input_data, data, len);
ps->receive_urgent = (urgent != 0);
ps->receive_data = data;
ps->receive_len = len;
ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
} else {
plug_receive(ps->plug, urgent, data, len);
}
}
static void plug_proxy_sent (Plug *p, size_t bufsize)
{
ProxySocket *ps = container_of(p, ProxySocket, plugimpl);
if (ps->state != PROXY_STATE_ACTIVE) {
ps->negotiate(ps, PROXY_CHANGE_SENT);
return;
}
plug_sent(ps->plug, bufsize);
}
static int plug_proxy_accepting(Plug *p,
accept_fn_t constructor, accept_ctx_t ctx)
{
ProxySocket *ps = container_of(p, ProxySocket, plugimpl);
if (ps->state != PROXY_STATE_ACTIVE) {
ps->accepting_constructor = constructor;
ps->accepting_ctx = ctx;
return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
}
return plug_accepting(ps->plug, constructor, ctx);
}
/*
* This function can accept a NULL pointer as `addr', in which case
* it will only check the host name.
*/
bool proxy_for_destination (SockAddr *addr, const char *hostname,
int port, Conf *conf)
{
int s = 0, e = 0;
char hostip[64];
int hostip_len, hostname_len;
const char *exclude_list;
/*
* Special local connections such as Unix-domain sockets
* unconditionally cannot be proxied, even in proxy-localhost
* mode. There just isn't any way to ask any known proxy type for
* them.
*/
if (addr && sk_address_is_special_local(addr))
return false; /* do not proxy */
/*
* Check the host name and IP against the hard-coded
* representations of `localhost'.
*/
if (!conf_get_bool(conf, CONF_even_proxy_localhost) &&
(sk_hostname_is_local(hostname) ||
(addr && sk_address_is_local(addr))))
return false; /* do not proxy */
/* we want a string representation of the IP address for comparisons */
if (addr) {
sk_getaddr(addr, hostip, 64);
hostip_len = strlen(hostip);
} else
hostip_len = 0; /* placate gcc; shouldn't be required */
hostname_len = strlen(hostname);
exclude_list = conf_get_str(conf, CONF_proxy_exclude_list);
/* now parse the exclude list, and see if either our IP
* or hostname matches anything in it.
*/
while (exclude_list[s]) {
while (exclude_list[s] &&
(isspace((unsigned char)exclude_list[s]) ||
exclude_list[s] == ',')) s++;
if (!exclude_list[s]) break;
e = s;
while (exclude_list[e] &&
(isalnum((unsigned char)exclude_list[e]) ||
exclude_list[e] == '-' ||
exclude_list[e] == '.' ||
exclude_list[e] == '*')) e++;
if (exclude_list[s] == '*') {
/* wildcard at beginning of entry */
if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
exclude_list + s + 1, e - s - 1) == 0) ||
strnicmp(hostname + hostname_len - (e - s - 1),
exclude_list + s + 1, e - s - 1) == 0) {
/* IP/hostname range excluded. do not use proxy. */
return false;
}
} else if (exclude_list[e-1] == '*') {
/* wildcard at end of entry */
if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
strnicmp(hostname, exclude_list + s, e - s - 1) == 0) {
/* IP/hostname range excluded. do not use proxy. */
return false;
}
} else {
/* no wildcard at either end, so let's try an absolute
* match (ie. a specific IP)
*/
if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
return false; /* IP/hostname excluded. do not use proxy. */
if (strnicmp(hostname, exclude_list + s, e - s) == 0)
return false; /* IP/hostname excluded. do not use proxy. */
}
s = e;
/* Make sure we really have reached the next comma or end-of-string */
while (exclude_list[s] &&
!isspace((unsigned char)exclude_list[s]) &&
exclude_list[s] != ',') s++;
}
/* no matches in the exclude list, so use the proxy */
return true;
}
static char *dns_log_msg(const char *host, int addressfamily,
const char *reason)
{
return dupprintf("Looking up host \"%s\"%s for %s", host,
(addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
""), reason);
}
SockAddr *name_lookup(const char *host, int port, char **canonicalname,
Conf *conf, int addressfamily, LogContext *logctx,
const char *reason)
{
if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
do_proxy_dns(conf) &&
proxy_for_destination(NULL, host, port, conf)) {
if (logctx)
logeventf(logctx, "Leaving host lookup to proxy of \"%s\""
" (for %s)", host, reason);
*canonicalname = dupstr(host);
return sk_nonamelookup(host);
} else {
if (logctx)
logevent_and_free(
logctx, dns_log_msg(host, addressfamily, reason));
return sk_namelookup(host, canonicalname, addressfamily);
}
}
static const struct SocketVtable ProxySocket_sockvt = {
sk_proxy_plug,
sk_proxy_close,
sk_proxy_write,
sk_proxy_write_oob,
sk_proxy_write_eof,
sk_proxy_flush,
sk_proxy_set_frozen,
sk_proxy_socket_error,
NULL, /* peer_info */
};
static const struct PlugVtable ProxySocket_plugvt = {
plug_proxy_log,
plug_proxy_closing,
plug_proxy_receive,
plug_proxy_sent,
plug_proxy_accepting
};
Socket *new_connection(SockAddr *addr, const char *hostname,
int port, bool privport,
bool oobinline, bool nodelay, bool keepalive,
Plug *plug, Conf *conf)
{
if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
proxy_for_destination(addr, hostname, port, conf))
{
ProxySocket *ret;
SockAddr *proxy_addr;
char *proxy_canonical_name;
const char *proxy_type;
Socket *sret;
int type;
if ((sret = platform_new_connection(addr, hostname, port, privport,
oobinline, nodelay, keepalive,
plug, conf)) !=
NULL)
return sret;
ret = snew(ProxySocket);
ret->sock.vt = &ProxySocket_sockvt;
ret->plugimpl.vt = &ProxySocket_plugvt;
ret->conf = conf_copy(conf);
ret->plug = plug;
ret->remote_addr = addr; /* will need to be freed on close */
ret->remote_port = port;
ret->error = NULL;
ret->pending_flush = false;
ret->pending_eof = false;
ret->freeze = false;
bufchain_init(&ret->pending_input_data);
bufchain_init(&ret->pending_output_data);
bufchain_init(&ret->pending_oob_output_data);
ret->sub_socket = NULL;
ret->state = PROXY_STATE_NEW;
ret->negotiate = NULL;
type = conf_get_int(conf, CONF_proxy_type);
if (type == PROXY_HTTP) {
ret->negotiate = proxy_http_negotiate;
proxy_type = "HTTP";
} else if (type == PROXY_SOCKS4) {
ret->negotiate = proxy_socks4_negotiate;
proxy_type = "SOCKS 4";
} else if (type == PROXY_SOCKS5) {
ret->negotiate = proxy_socks5_negotiate;
proxy_type = "SOCKS 5";
} else if (type == PROXY_TELNET) {
ret->negotiate = proxy_telnet_negotiate;
proxy_type = "Telnet";
} else {
ret->error = "Proxy error: Unknown proxy method";
return &ret->sock;
}
{
char *logmsg = dupprintf("Will use %s proxy at %s:%d to connect"
" to %s:%d", proxy_type,
conf_get_str(conf, CONF_proxy_host),
conf_get_int(conf, CONF_proxy_port),
hostname, port);
plug_log(plug, 2, NULL, 0, logmsg, 0);
sfree(logmsg);
}
{
char *logmsg = dns_log_msg(conf_get_str(conf, CONF_proxy_host),
conf_get_int(conf, CONF_addressfamily),
"proxy");
plug_log(plug, 2, NULL, 0, logmsg, 0);
sfree(logmsg);
}
/* look-up proxy */
proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
&proxy_canonical_name,
conf_get_int(conf, CONF_addressfamily));
if (sk_addr_error(proxy_addr) != NULL) {
ret->error = "Proxy error: Unable to resolve proxy host name";
sk_addr_free(proxy_addr);
return &ret->sock;
}
sfree(proxy_canonical_name);
{
char addrbuf[256], *logmsg;
sk_getaddr(proxy_addr, addrbuf, lenof(addrbuf));
logmsg = dupprintf("Connecting to %s proxy at %s port %d",
proxy_type, addrbuf,
conf_get_int(conf, CONF_proxy_port));
plug_log(plug, 2, NULL, 0, logmsg, 0);
sfree(logmsg);
}
/* create the actual socket we will be using,
* connected to our proxy server and port.
*/
ret->sub_socket = sk_new(proxy_addr,
conf_get_int(conf, CONF_proxy_port),
privport, oobinline,
nodelay, keepalive, &ret->plugimpl);
if (sk_socket_error(ret->sub_socket) != NULL)
return &ret->sock;
/* start the proxy negotiation process... */
sk_set_frozen(ret->sub_socket, 0);
ret->negotiate(ret, PROXY_CHANGE_NEW);
return &ret->sock;
}
/* no proxy, so just return the direct socket */
return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
}
Socket *new_listener(const char *srcaddr, int port, Plug *plug,
bool local_host_only, Conf *conf, int addressfamily)
{
/* TODO: SOCKS (and potentially others) support inbound
* TODO: connections via the proxy. support them.
*/
return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
}
/* ----------------------------------------------------------------------
* HTTP CONNECT proxy type.
*/
static bool get_line_end(char *data, size_t len, size_t *out)
{
size_t off = 0;
while (off < len)
{
if (data[off] == '\n') {
/* we have a newline */
off++;
/* is that the only thing on this line? */
if (off <= 2) {
*out = off;
return true;
}
/* if not, then there is the possibility that this header
* continues onto the next line, if it starts with a space
* or a tab.
*/
if (off + 1 < len && data[off+1] != ' ' && data[off+1] != '\t') {
*out = off;
return true;
}
/* the line does continue, so we have to keep going
* until we see an the header's "real" end of line.
*/
off++;
}
off++;
}
return false;
}
int proxy_http_negotiate (ProxySocket *p, int change)
{
if (p->state == PROXY_STATE_NEW) {
/* we are just beginning the proxy negotiate process,
* so we'll send off the initial bits of the request.
* for this proxy method, it's just a simple HTTP
* request
*/
char *buf, dest[512];
char *username, *password;
sk_getaddr(p->remote_addr, dest, lenof(dest));
buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
dest, p->remote_port, dest, p->remote_port);
sk_write(p->sub_socket, buf, strlen(buf));
sfree(buf);
username = conf_get_str(p->conf, CONF_proxy_username);
password = conf_get_str(p->conf, CONF_proxy_password);
if (username[0] || password[0]) {
char *buf, *buf2;
int i, j, len;
buf = dupprintf("%s:%s", username, password);
len = strlen(buf);
buf2 = snewn(len * 4 / 3 + 100, char);
sprintf(buf2, "Proxy-Authorization: Basic ");
for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
base64_encode_atom((unsigned char *)(buf+i),
(len-i > 3 ? 3 : len-i), buf2+j);
strcpy(buf2+j, "\r\n");
sk_write(p->sub_socket, buf2, strlen(buf2));
sfree(buf);
sfree(buf2);
}
sk_write(p->sub_socket, "\r\n", 2);
p->state = 1;
return 0;
}
if (change == PROXY_CHANGE_CLOSING) {
/* if our proxy negotiation process involves closing and opening
* new sockets, then we would want to intercept this closing
* callback when we were expecting it. if we aren't anticipating
* a socket close, then some error must have occurred. we'll
* just pass those errors up to the backend.
*/
plug_closing(p->plug, p->closing_error_msg, p->closing_error_code,
p->closing_calling_back);
return 0; /* ignored */
}
if (change == PROXY_CHANGE_SENT) {
/* some (or all) of what we wrote to the proxy was sent.
* we don't do anything new, however, until we receive the
* proxy's response. we might want to set a timer so we can
* timeout the proxy negotiation after a while...
*/
return 0;
}
if (change == PROXY_CHANGE_ACCEPTING) {
/* we should _never_ see this, as we are using our socket to
* connect to a proxy, not accepting inbound connections.
* what should we do? close the socket with an appropriate
* error message?
*/
return plug_accepting(p->plug,
p->accepting_constructor, p->accepting_ctx);
}
if (change == PROXY_CHANGE_RECEIVE) {
/* we have received data from the underlying socket, which
* we'll need to parse, process, and respond to appropriately.
*/
char *data, *datap;
size_t len, eol;
if (p->state == 1) {
int min_ver, maj_ver, status;
/* get the status line */
len = bufchain_size(&p->pending_input_data);
assert(len > 0); /* or we wouldn't be here */
data = snewn(len+1, char);
bufchain_fetch(&p->pending_input_data, data, len);
/*
* We must NUL-terminate this data, because Windows
* sscanf appears to require a NUL at the end of the
* string because it strlens it _first_. Sigh.
*/
data[len] = '\0';
if (!get_line_end(data, len, &eol)) {
sfree(data);
return 1;
}
status = -1;
/* We can't rely on whether the %n incremented the sscanf return */
if (sscanf((char *)data, "HTTP/%i.%i %n",
&maj_ver, &min_ver, &status) < 2 || status == -1) {
plug_closing(p->plug, "Proxy error: HTTP response was absent",
PROXY_ERROR_GENERAL, 0);
sfree(data);
return 1;
}
/* remove the status line from the input buffer. */
bufchain_consume(&p->pending_input_data, eol);
if (data[status] != '2') {
/* error */
char *buf;
data[eol] = '\0';
while (eol > status &&
(data[eol-1] == '\r' || data[eol-1] == '\n'))
data[--eol] = '\0';
buf = dupprintf("Proxy error: %s", data+status);
plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
sfree(buf);
sfree(data);
return 1;
}
sfree(data);
p->state = 2;
}
if (p->state == 2) {
/* get headers. we're done when we get a
* header of length 2, (ie. just "\r\n")
*/
len = bufchain_size(&p->pending_input_data);
assert(len > 0); /* or we wouldn't be here */
data = snewn(len, char);
datap = data;
bufchain_fetch(&p->pending_input_data, data, len);
if (!get_line_end(datap, len, &eol)) {
sfree(data);
return 1;
}
while (eol > 2) {
bufchain_consume(&p->pending_input_data, eol);
datap += eol;
len -= eol;
if (!get_line_end(datap, len, &eol))
eol = 0; /* terminate the loop */
}
if (eol == 2) {
/* we're done */
bufchain_consume(&p->pending_input_data, 2);
proxy_activate(p);
/* proxy activate will have dealt with
* whatever is left of the buffer */
sfree(data);
return 1;
}
sfree(data);
return 1;
}
}
plug_closing(p->plug, "Proxy error: unexpected proxy error",
PROXY_ERROR_UNEXPECTED, 0);
return 1;
}
/* ----------------------------------------------------------------------
* SOCKS proxy type.
*/
/* SOCKS version 4 */
int proxy_socks4_negotiate (ProxySocket *p, int change)
{
if (p->state == PROXY_CHANGE_NEW) {
/* request format:
* version number (1 byte) = 4
* command code (1 byte)
* 1 = CONNECT
* 2 = BIND
* dest. port (2 bytes) [network order]
* dest. address (4 bytes)
* user ID (variable length, null terminated string)
*/
strbuf *command = strbuf_new();
char hostname[512];
bool write_hostname = false;
put_byte(command, 4); /* SOCKS version 4 */
put_byte(command, 1); /* CONNECT command */
put_uint16(command, p->remote_port);
switch (sk_addrtype(p->remote_addr)) {
case ADDRTYPE_IPV4:
{
char addr[4];
sk_addrcopy(p->remote_addr, addr);
put_data(command, addr, 4);
break;
}
case ADDRTYPE_NAME:
sk_getaddr(p->remote_addr, hostname, lenof(hostname));
put_uint32(command, 1);
write_hostname = true;
break;
case ADDRTYPE_IPV6:
p->error = "Proxy error: SOCKS version 4 does not support IPv6";
strbuf_free(command);
return 1;
}
put_asciz(command, conf_get_str(p->conf, CONF_proxy_username));
if (write_hostname)
put_asciz(command, hostname);
sk_write(p->sub_socket, command->s, command->len);
strbuf_free(command);
p->state = 1;
return 0;
}
if (change == PROXY_CHANGE_CLOSING) {
/* if our proxy negotiation process involves closing and opening
* new sockets, then we would want to intercept this closing
* callback when we were expecting it. if we aren't anticipating
* a socket close, then some error must have occurred. we'll
* just pass those errors up to the backend.
*/
plug_closing(p->plug, p->closing_error_msg, p->closing_error_code,
p->closing_calling_back);
return 0; /* ignored */
}
if (change == PROXY_CHANGE_SENT) {
/* some (or all) of what we wrote to the proxy was sent.
* we don't do anything new, however, until we receive the
* proxy's response. we might want to set a timer so we can
* timeout the proxy negotiation after a while...
*/
return 0;
}
if (change == PROXY_CHANGE_ACCEPTING) {
/* we should _never_ see this, as we are using our socket to
* connect to a proxy, not accepting inbound connections.
* what should we do? close the socket with an appropriate
* error message?
*/
return plug_accepting(p->plug,
p->accepting_constructor, p->accepting_ctx);
}
if (change == PROXY_CHANGE_RECEIVE) {
/* we have received data from the underlying socket, which
* we'll need to parse, process, and respond to appropriately.
*/
if (p->state == 1) {
/* response format:
* version number (1 byte) = 4
* reply code (1 byte)
* 90 = request granted
* 91 = request rejected or failed
* 92 = request rejected due to lack of IDENTD on client
* 93 = request rejected due to difference in user ID
* (what we sent vs. what IDENTD said)
* dest. port (2 bytes)
* dest. address (4 bytes)
*/
char data[8];
if (bufchain_size(&p->pending_input_data) < 8)
return 1; /* not got anything yet */
/* get the response */
bufchain_fetch(&p->pending_input_data, data, 8);
if (data[0] != 0) {
plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
"unexpected reply code version",
PROXY_ERROR_GENERAL, 0);
return 1;
}
if (data[1] != 90) {
switch (data[1]) {
case 92:
plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
PROXY_ERROR_GENERAL, 0);
break;
case 93:
plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
PROXY_ERROR_GENERAL, 0);
break;
case 91:
default:
plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
PROXY_ERROR_GENERAL, 0);
break;
}
return 1;
}
bufchain_consume(&p->pending_input_data, 8);
/* we're done */
proxy_activate(p);
/* proxy activate will have dealt with
* whatever is left of the buffer */
return 1;
}
}
plug_closing(p->plug, "Proxy error: unexpected proxy error",
PROXY_ERROR_UNEXPECTED, 0);
return 1;
}
/* SOCKS version 5 */
int proxy_socks5_negotiate (ProxySocket *p, int change)
{
if (p->state == PROXY_CHANGE_NEW) {
/* initial command:
* version number (1 byte) = 5
* number of available authentication methods (1 byte)
* available authentication methods (1 byte * previous value)
* authentication methods:
* 0x00 = no authentication
* 0x01 = GSSAPI
* 0x02 = username/password
* 0x03 = CHAP
*/
strbuf *command;
char *username, *password;
int method_count_offset, methods_start;
command = strbuf_new();
put_byte(command, 5); /* SOCKS version 5 */
username = conf_get_str(p->conf, CONF_proxy_username);
password = conf_get_str(p->conf, CONF_proxy_password);
method_count_offset = command->len;
put_byte(command, 0);
methods_start = command->len;
put_byte(command, 0x00); /* no authentication */
if (username[0] || password[0]) {
proxy_socks5_offerencryptedauth(BinarySink_UPCAST(command));
put_byte(command, 0x02); /* username/password */
}
command->u[method_count_offset] = command->len - methods_start;
sk_write(p->sub_socket, command->s, command->len);
strbuf_free(command);
p->state = 1;
return 0;
}
if (change == PROXY_CHANGE_CLOSING) {
/* if our proxy negotiation process involves closing and opening
* new sockets, then we would want to intercept this closing
* callback when we were expecting it. if we aren't anticipating
* a socket close, then some error must have occurred. we'll
* just pass those errors up to the backend.
*/
plug_closing(p->plug, p->closing_error_msg, p->closing_error_code,
p->closing_calling_back);
return 0; /* ignored */
}
if (change == PROXY_CHANGE_SENT) {
/* some (or all) of what we wrote to the proxy was sent.
* we don't do anything new, however, until we receive the
* proxy's response. we might want to set a timer so we can
* timeout the proxy negotiation after a while...
*/
return 0;
}
if (change == PROXY_CHANGE_ACCEPTING) {
/* we should _never_ see this, as we are using our socket to
* connect to a proxy, not accepting inbound connections.
* what should we do? close the socket with an appropriate
* error message?
*/
return plug_accepting(p->plug,
p->accepting_constructor, p->accepting_ctx);
}
if (change == PROXY_CHANGE_RECEIVE) {
/* we have received data from the underlying socket, which
* we'll need to parse, process, and respond to appropriately.
*/
if (p->state == 1) {
/* initial response:
* version number (1 byte) = 5
* authentication method (1 byte)
* authentication methods: