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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.48 by pcg, Tue Jul 28 00:42:14 2009 UTC vs.
Revision 1.51 by root, Sun Mar 6 19:40:28 2011 UTC

1/* 1/*
2 vpn_dns.C -- handle the dns tunnel part of the protocol. 2 vpn_dns.C -- handle the dns tunnel part of the protocol.
3 Copyright (C) 2003-2008 Marc Lehmann <gvpe@schmorp.de> 3 Copyright (C) 2003-2011 Marc Lehmann <gvpe@schmorp.de>
4 4
5 This file is part of GVPE. 5 This file is part of GVPE.
6 6
7 GVPE is free software; you can redistribute it and/or modify it 7 GVPE is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the 8 under the terms of the GNU General Public License as published by the
… …
59 59
60#include "netcompat.h" 60#include "netcompat.h"
61 61
62#include "vpn.h" 62#include "vpn.h"
63 63
64#define MIN_POLL_INTERVAL 0.1 // poll at most this often when no data received
64#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data 65#define MAX_POLL_INTERVAL 1. // how often to poll minimally when the server has no data
65#define ACTIVITY_INTERVAL 5.
66 66
67#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
69 69
70#define MAX_SEND_INTERVAL 2. // optimistic? 70#define MAX_SEND_INTERVAL 2. // optimistic?
… …
91#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
92 92
93#define CMD_IP_1 207 93#define CMD_IP_1 207
94#define CMD_IP_2 46 94#define CMD_IP_2 46
95#define CMD_IP_3 236 95#define CMD_IP_3 236
96#define CMD_IP_RST 29 96
97#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
98#define CMD_IP_REJ 32 98#define CMD_IP_REJ 32 // do not want you
99#define CMD_IP_SYN 113 // connection established
100#define CMD_IP_CSE 213 // connection established, but likely case mismatch
101
102static bool
103is_uc (char c)
104{
105 return 'A' <= c && c <= 'Z';
106}
107
108static bool
109is_lc (char c)
110{
111 return 'a' <= c && c <= 'z';
112}
99 113
100// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
101struct charmap 115struct charmap
102{ 116{
103 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
117 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
118 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
119 133
120 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
121 { 135 {
136 char c = cmap [size];
137
122 enc [size] = cmap [size]; 138 enc [size] = c;
123 dec [(u8)enc [size]] = size; 139 dec [(u8)c] = size;
140
141 // allow lowercase/uppercase aliases if possible
142 if (is_uc (c) && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size;
143 if (is_lc (c) && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size;
124 } 144 }
125 145
126 assert (size < 256); 146 assert (size < 256);
127} 147}
128 148
… …
135{ 155{
136 charmap cmap; 156 charmap cmap;
137 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
138 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
139 159
140 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
141 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
142 162
143 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
144 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
145 165
146 basecoder (const char *cmap); 166 basecoder (const char *cmap);
147}; 167};
148 168
149basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
168 enc_len [len] = n; 188 enc_len [len] = n;
169 dec_len [n] = len; 189 dec_len [n] = len;
170 } 190 }
171} 191}
172 192
193unsigned int
173unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
174{ 195{
175 return enc_len [len]; 196 return enc_len [len];
176} 197}
177 198
199unsigned int
178unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
179{ 201{
180 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
181 --len; 203 --len;
182 204
183 return dec_len [len]; 205 return dec_len [len];
184} 206}
185 207
208unsigned int
186unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
187{ 210{
188 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
189 return 0; 212 return 0;
190 213
191 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
210 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
211 234
212 return elen; 235 return elen;
213} 236}
214 237
238unsigned int
215unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
216{ 240{
217 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
218 return 0; 242 return 0;
219 243
220 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
269 } 293 }
270 abort (); 294 abort ();
271} 295}
272#endif 296#endif
273 297
274//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
275//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
276static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
277//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
278static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
279 301
280///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
281 303
282#define HDRSIZE 6 304#define HDRSIZE 5
283 305
306inline void
284inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
285{ 308{
309 assert (clientid < 256);
310
286 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
287 312
288 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
289 clientid, 316 clientid,
290 (seqno >> 8) | (retry << 6),
291 seqno,
292 }; 317 };
293 318
294 assert (clientid < 256);
295
296 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
297} 320}
298 321
322inline void
299inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
300{ 324{
301 u8 hdr[3]; 325 u8 hdr[3];
302 326
303 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
304 328
305 clientid = hdr[0]; 329 clientid = hdr[2];
306 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
307} 331}
308 332
309///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
310 334
311struct byte_stream 335struct byte_stream
… …
337byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
338{ 362{
339 delete data; 363 delete data;
340} 364}
341 365
366void
342void byte_stream::remove (int count) 367byte_stream::remove (int count)
343{ 368{
344 if (count > fill) 369 if (count > fill)
345 assert (count <= fill); 370 assert (count <= fill);
346 371
347 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
348} 373}
349 374
375bool
350bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
351{ 377{
352 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
353 return false; 379 return false;
354 380
355 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
356 382
357 return true; 383 return true;
358} 384}
359 385
386bool
360bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
361{ 388{
362 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
363 return false; 390 return false;
364 391
365 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
… …
421 448
422struct dns_cfg 449struct dns_cfg
423{ 450{
424 static int next_uid; 451 static int next_uid;
425 452
426 u8 id1, id2, id3, id4; 453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
427 456
428 u8 version; 457 u8 version;
429 u8 flags; 458 u8 flags;
430 u8 rrtype; 459 u16 max_size;
460
461 u8 id1, id2, id3, id4;
462
463 u16 client;
431 u8 def_ttl; 464 u8 def_ttl;
465 u8 r0;
432 466
433 u16 client; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
434 u16 uid; // to make request unique 468 u8 hdr_cdc; // cdc en/decoder for regular request headers
469 u8 req_cdc; // cdc en/decoder for regular (ANY?) request data
470 u8 rep_cdc; // cdc en/decoder for regular (TXT) replies, 0 == 8 bit encoding
435 471
436 u16 max_size;
437 u8 seq_cdc;
438 u8 req_cdc;
439
440 u8 rep_cdc;
441 u8 delay; // time in 0.01s units that the server may delay replying packets
442 u8 r3, r4;
443
444 u8 r5, r6, r7, r8; 472 u8 r1, r2, r3, r4;
445 473
446 void reset (int clientid); 474 void reset (int clientid);
447 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
448}; 477};
449 478
450int dns_cfg::next_uid; 479int dns_cfg::next_uid;
451 480
481void
452void dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
453{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
454 id1 = 'G'; 485 id1 = 'G';
455 id2 = 'V'; 486 id2 = 'V';
456 id3 = 'P'; 487 id3 = 'P';
457 id4 = 'E'; 488 id4 = 'E';
458 489
459 version = 1; 490 version = 2;
460 491
461 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
462 flags = 0; 493 flags = 0;
463 def_ttl = 0; 494 def_ttl = 0;
464 seq_cdc = 26; 495 syn_cdc = 26;
465 req_cdc = 62; 496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
466 rep_cdc = 0; 498 rep_cdc = 0;
467 max_size = htons (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
468 client = htons (clientid); 500 client = htons (clientid);
469 uid = next_uid++; 501 uid = ++next_uid;
470 delay = 0;
471 502
472 r3 = r4 = 0; 503 r0 = r1 = r2 = r3 = r4 = 0;
473 r4 = r5 = r6 = r7 = 0;
474}
475 504
505 chksum = get_chksum ();
506}
507
508// simple but not trivial chksum
509u8
510dns_cfg::get_chksum ()
511{
512 unsigned int sum = 0xff00; // only 16 bits required
513
514 u8 old_chksum = chksum;
515 chksum = 0;
516
517 for (unsigned int i = 0; i < sizeof (*this); ++i)
518 sum += ((u8 *)this)[i] * (i + 1);
519
520 chksum = old_chksum;
521
522 return sum + (sum >> 8);
523}
524
525bool
476bool dns_cfg::valid () 526dns_cfg::valid ()
477{ 527{
478 // although the protocol itself allows for some configurability, 528 // although the protocol itself allows for some configurability,
479 // only the following encoding/decoding settings are implemented. 529 // only the following encoding/decoding settings are implemented.
480 return id1 == 'G' 530 return id1 == 'G'
481 && id2 == 'V' 531 && id2 == 'V'
482 && id3 == 'P' 532 && id3 == 'P'
483 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
484 && seq_cdc == 26 535 && syn_cdc == 26
485 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
486 && rep_cdc == 0 538 && rep_cdc == 0
487 && version == 1; 539 && chksum == get_chksum ();
488} 540}
489 541
490struct dns_packet : net_packet 542struct dns_packet : net_packet
491{ 543{
492 u16 id; 544 u16 id;
… …
496 u8 data [MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
497 549
498 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
499}; 551};
500 552
553int
501int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
502{ 555{
503 char *orig = data; 556 char *orig = data;
504 557
505 memset (data, 0, size); 558 memset (data, 0, size);
506 559
… …
532 return data - orig; 585 return data - orig;
533} 586}
534 587
535///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
536 589
590static
591u16 next_id ()
592{
537static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
538 594
539static u16 next_id ()
540{
541 if (!dns_id) 595 if (!dns_id)
542 dns_id = time (0); 596 dns_id = time (0);
543 597
544 // the simplest lsfr with periodicity 65535 i could find 598 // the simplest lsfr with periodicity 65535 i could find
545 dns_id = (dns_id << 1) 599 dns_id = (dns_id << 1)
… …
560 struct vpn *vpn; 614 struct vpn *vpn;
561 615
562 dns_cfg cfg; 616 dns_cfg cfg;
563 617
564 bool established; 618 bool established;
619 const basecoder *cdc;
565 620
566 tstamp last_received; 621 tstamp last_received;
567 tstamp last_sent; 622 tstamp last_sent;
568 double min_latency; 623 double min_latency;
569 double poll_interval, send_interval; 624 double poll_interval, send_interval;
… …
573 byte_stream rcvdq; int rcvseq; int repseq; 628 byte_stream rcvdq; int rcvseq; int repseq;
574 byte_stream snddq; int sndseq; 629 byte_stream snddq; int sndseq;
575 630
576 inline void time_cb (ev::timer &w, int revents); ev::timer tw; 631 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
577 void receive_rep (dns_rcv *r); 632 void receive_rep (dns_rcv *r);
633
634 void reset (); // quite like tcp RST
635 void set_cfg (); // to be called after any cfg changes
578 636
579 dns_connection (connection *c); 637 dns_connection (connection *c);
580 ~dns_connection (); 638 ~dns_connection ();
581}; 639};
582 640
… …
613dns_snd::~dns_snd () 671dns_snd::~dns_snd ()
614{ 672{
615 delete pkt; 673 delete pkt;
616} 674}
617 675
676static void
618static void append_domain (dns_packet &pkt, int &offs, const char *domain) 677append_domain (dns_packet &pkt, int &offs, const char *domain)
619{ 678{
620 // add tunnel domain 679 // add tunnel domain
621 for (;;) 680 for (;;)
622 { 681 {
623 const char *end = strchr (domain, '.'); 682 const char *end = strchr (domain, '.');
… …
636 695
637 domain = end + 1; 696 domain = end + 1;
638 } 697 }
639} 698}
640 699
700void
641void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 701dns_snd::gen_stream_req (int seqno, byte_stream &stream)
642{ 702{
643 stdhdr = true; 703 stdhdr = true;
644 this->seqno = seqno; 704 this->seqno = seqno;
645 705
646 timeout = ev_now () + INITIAL_TIMEOUT; 706 timeout = ev_now () + INITIAL_TIMEOUT;
… …
654 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 714 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
655 715
656 char enc[256], *encp = enc; 716 char enc[256], *encp = enc;
657 encode_header (enc, THISNODE->id, seqno); 717 encode_header (enc, THISNODE->id, seqno);
658 718
659 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 719 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
660 720
661 if (datalen > stream.size ()) 721 if (datalen > stream.size ())
662 datalen = stream.size (); 722 datalen = stream.size ();
663 723
664 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 724 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
665 stream.remove (datalen); 725 stream.remove (datalen);
666 726
667 while (enclen) 727 while (enclen)
668 { 728 {
669 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 729 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
684 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 744 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
685 745
686 pkt->len = offs; 746 pkt->len = offs;
687} 747}
688 748
749void
689void dns_snd::gen_syn_req () 750dns_snd::gen_syn_req ()
690{ 751{
691 timeout = ev_now () + INITIAL_SYN_TIMEOUT; 752 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
692 753
693 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 754 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
694 pkt->qdcount = htons (1); 755 pkt->qdcount = htons (1);
… …
741{ 802{
742 tw.set<dns_connection, &dns_connection::time_cb> (this); 803 tw.set<dns_connection, &dns_connection::time_cb> (this);
743 804
744 vpn = c->vpn; 805 vpn = c->vpn;
745 806
807 reset ();
808}
809
810dns_connection::~dns_connection ()
811{
812 reset ();
813}
814
815void
816dns_connection::reset ()
817{
818 while (!rcvpq.empty ())
819 {
820 delete rcvpq.back ();
821 rcvpq.pop_back ();
822 }
823
824 for (int i = vpn->dns_sndpq.size (); i--; )
825 if (vpn->dns_sndpq [i]->dns == this)
826 {
827 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
828 vpn->dns_sndpq.pop_back ();
829 }
830
746 established = false; 831 established = false;
747 832
748 rcvseq = repseq = sndseq = 0; 833 rcvseq = repseq = sndseq = 0;
749 834
750 last_sent = last_received = 0; 835 last_sent = last_received = 0;
751 poll_interval = 0.5; // starting here 836 poll_interval = 0.5; // starting here
752 send_interval = 0.5; // starting rate 837 send_interval = 0.5; // starting rate
753 min_latency = INITIAL_TIMEOUT; 838 min_latency = INITIAL_TIMEOUT;
754} 839}
755 840
756dns_connection::~dns_connection () 841void
842dns_connection::set_cfg ()
757{ 843{
758 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 844 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
759 i != rcvpq.end ();
760 ++i)
761 delete *i;
762} 845}
763 846
847void
764void dns_connection::receive_rep (dns_rcv *r) 848dns_connection::receive_rep (dns_rcv *r)
765{ 849{
766 if (r->datalen) 850 if (r->datalen)
767 { 851 {
768 last_received = ev_now (); 852 last_received = ev_now ();
769 tw (); 853 tw ();
… …
802 886
803 rcvseq = (rcvseq + 1) & SEQNO_MASK; 887 rcvseq = (rcvseq + 1) & SEQNO_MASK;
804 888
805 if (!rcvdq.put (r->data, r->datalen)) 889 if (!rcvdq.put (r->data, r->datalen))
806 { 890 {
891 // MUST never overflow, can be caused by data corruption, TODO
807 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 892 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
808 abort (); // MUST never overflow, can be caused by data corruption, TODO 893 reset ();
894 return;
809 } 895 }
810 896
811 while (vpn_packet *pkt = rcvdq.get ()) 897 while (vpn_packet *pkt = rcvdq.get ())
812 { 898 {
813 sockinfo si; 899 sockinfo si;
814 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; 900 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
815 901
816 vpn->recv_vpn_packet (pkt, si); 902 vpn->recv_vpn_packet (pkt, si);
817
818 delete pkt; 903 delete pkt;
819 } 904 }
820 905
821 // check for further packets 906 // check for further packets
822 goto redo; 907 goto redo;
… …
865 { 950 {
866 // correct class, domain: parse 951 // correct class, domain: parse
867 int client, seqno; 952 int client, seqno;
868 decode_header (qname, client, seqno); 953 decode_header (qname, client, seqno);
869 954
870 u8 data[MAXSIZE];
871 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
872
873 if (0 < client && client <= conns.size ()) 955 if (0 < client && client <= conns.size ())
874 { 956 {
875 connection *c = conns [client - 1]; 957 connection *c = conns [client - 1];
876 dns_connection *dns = c->dns; 958 dns_connection *dns = c->dns;
877 dns_rcv *rcv; 959 dns_rcv *rcv;
878 960
879 if (dns) 961 if (dns)
880 { 962 {
963 u8 data[MAXSIZE];
964 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
965
881 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 966 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
882 if (SEQNO_EQ ((*i)->seqno, seqno)) 967 if (SEQNO_EQ ((*i)->seqno, seqno))
883 { 968 {
884 // already seen that request: simply reply with the cached reply 969 // already seen that request: simply reply with the cached reply
885 dns_rcv *r = *i; 970 dns_rcv *r = *i;
… …
986 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1071 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
987 pkt [offs++] = 0; pkt [offs++] = 0; 1072 pkt [offs++] = 0; pkt [offs++] = 0;
988 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1073 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
989 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1074 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
990 1075
991 slog (L_INFO, _("DNS: client %d connects"), client);
992
993 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1076 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
994 pkt [offs++] = CMD_IP_REJ; 1077 pkt [offs++] = CMD_IP_REJ;
995 1078
996 if (0 < client && client <= conns.size ()) 1079 if (0 < client && client <= conns.size ())
997 { 1080 {
998 connection *c = conns [client - 1]; 1081 connection *c = conns [client - 1];
999 1082
1000 if (cfg.valid ()) 1083 if (cfg.valid ())
1001 { 1084 {
1002 pkt [offs - 1] = CMD_IP_SYN; 1085 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1086
1087 // check for any encoding mismatches - hints at a case problem
1088 char qname2 [MAX_ENC_LEN];
1089 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
1003 1090
1004 delete c->dns; 1091 delete c->dns;
1092
1093 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1094 ? CMD_IP_CSE : CMD_IP_SYN;
1095
1005 c->dns = new dns_connection (c); 1096 c->dns = new dns_connection (c);
1006 c->dns->cfg = cfg; 1097 c->dns->cfg = cfg;
1098 c->dns->set_cfg ();
1007 } 1099 }
1008 } 1100 }
1009 } 1101 }
1010 } 1102 }
1011 1103
… …
1031 dns_connection *dns = (*i)->dns; 1123 dns_connection *dns = (*i)->dns;
1032 connection *c = dns->c; 1124 connection *c = dns->c;
1033 int seqno = (*i)->seqno; 1125 int seqno = (*i)->seqno;
1034 u8 data[MAXSIZE], *datap = data; 1126 u8 data[MAXSIZE], *datap = data;
1035 //printf ("rcv pkt %x\n", seqno);//D 1127 //printf ("rcv pkt %x\n", seqno);//D
1128 bool back_off = (*i)->retry;
1036 1129
1037 if ((*i)->retry) 1130 if (back_off)
1038 { 1131 {
1039 dns->send_interval *= 1.01; 1132 dns->send_interval *= 1.01;
1040 if (dns->send_interval > MAX_SEND_INTERVAL) 1133 if (dns->send_interval > MAX_SEND_INTERVAL)
1041 dns->send_interval = MAX_SEND_INTERVAL; 1134 dns->send_interval = MAX_SEND_INTERVAL;
1042 } 1135 }
… …
1082 ttl |= pkt [offs++] << 16; 1175 ttl |= pkt [offs++] << 16;
1083 ttl |= pkt [offs++] << 8; 1176 ttl |= pkt [offs++] << 8;
1084 ttl |= pkt [offs++]; 1177 ttl |= pkt [offs++];
1085 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1178 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1086 1179
1087 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1180 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1088 { 1181 {
1089 if (rdlen <= MAXSIZE - offs) 1182 if (rdlen <= MAXSIZE - offs)
1090 { 1183 {
1091 // decode bytes, finally 1184 // decode bytes, finally
1092 1185
… …
1118 { 1211 {
1119 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1212 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1120 1213
1121 if (ip [3] == CMD_IP_RST) 1214 if (ip [3] == CMD_IP_RST)
1122 { 1215 {
1123 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1216 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1124 1217
1125 delete dns; c->dns = 0; 1218 dns->reset ();
1126
1127 return; 1219 return;
1128 } 1220 }
1129 else if (ip [3] == CMD_IP_SYN) 1221 else if (ip [3] == CMD_IP_SYN)
1130 { 1222 {
1131 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1223 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1132 dns->established = true; 1224 dns->established = true;
1133 } 1225 }
1226 else if (ip [3] == CMD_IP_CSE)
1227 {
1228 if (conf.dns_case_preserving)
1229 {
1230 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1231 conf.dns_case_preserving = false;
1232 dns->reset ();
1233 return;
1234 }
1235 else
1236 {
1237 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1238 dns->established = true;
1239 }
1240 }
1134 else if (ip [3] == CMD_IP_REJ) 1241 else if (ip [3] == CMD_IP_REJ)
1135 { 1242 {
1136 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1243 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1137 abort (); 1244 dns->tw.start (60.);
1138 } 1245 }
1139 else 1246 else
1247 {
1140 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1248 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1249 dns->tw.start (60.);
1250 }
1141 } 1251 }
1142 else 1252 else
1143 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1253 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1144 ip [0], ip [1], ip [2], ip [3]); 1254 ip [0], ip [1], ip [2], ip [3]);
1145 1255
… …
1163 } 1273 }
1164 1274
1165 // todo: pkt now used 1275 // todo: pkt now used
1166 if (datap) 1276 if (datap)
1167 dns->receive_rep (new dns_rcv (seqno, data, datap - data)); 1277 dns->receive_rep (new dns_rcv (seqno, data, datap - data));
1278 else if (dns_sndpq.empty ()) // no data received, and nothing to send - idle
1279 {
1280 dns->send_interval *= 1.1;
1281
1282 if (dns->send_interval < MIN_POLL_INTERVAL)
1283 dns->send_interval = MIN_POLL_INTERVAL;
1284
1285 if (dns->send_interval > MAX_POLL_INTERVAL && !back_off)
1286 dns->send_interval = MAX_POLL_INTERVAL;
1287 }
1168 1288
1169 break; 1289 break;
1170 } 1290 }
1171} 1291}
1172 1292
… …
1213 1333
1214 // always return true even if the buffer overflows 1334 // always return true even if the buffer overflows
1215 return true; 1335 return true;
1216} 1336}
1217 1337
1218void
1219connection::dnsv4_reset_connection ()
1220{
1221 //delete dns; dns = 0; //TODO
1222}
1223
1224#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1338#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1225 1339
1226void 1340void
1227dns_connection::time_cb (ev::timer &w, int revents) 1341dns_connection::time_cb (ev::timer &w, int revents)
1228{ 1342{
… …
1269 if (vpn->dns_sndpq.empty ()) 1383 if (vpn->dns_sndpq.empty ())
1270 { 1384 {
1271 send = new dns_snd (this); 1385 send = new dns_snd (this);
1272 1386
1273 cfg.reset (THISNODE->id); 1387 cfg.reset (THISNODE->id);
1388 set_cfg ();
1274 send->gen_syn_req (); 1389 send->gen_syn_req ();
1275 } 1390 }
1276 } 1391 }
1277 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1392 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1278 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1393 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))

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