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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.42 by pcg, Sat Nov 10 05:14:22 2007 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) 2003-2005 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 7 GVPE is free software; you can redistribute it and/or modify it
8 it under the terms of the GNU General Public License as published by 8 under the terms of the GNU General Public License as published by the
9 the Free Software Foundation; either version 2 of the License, or 9 Free Software Foundation; either version 3 of the License, or (at your
10 (at your option) any later version. 10 option) any later version.
11 11
12 This program is distributed in the hope that it will be useful, 12 This program is distributed in the hope that it will be useful, but
13 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15 GNU General Public License for more details. 15 Public License for more details.
16 16
17 You should have received a copy of the GNU General Public License 17 You should have received a copy of the GNU General Public License along
18 along with gvpe; if not, write to the Free Software 18 with this program; if not, see <http://www.gnu.org/licenses/>.
19 Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19
20 Additional permission under GNU GPL version 3 section 7
21
22 If you modify this Program, or any covered work, by linking or
23 combining it with the OpenSSL project's OpenSSL library (or a modified
24 version of that library), containing parts covered by the terms of the
25 OpenSSL or SSLeay licenses, the licensors of this Program grant you
26 additional permission to convey the resulting work. Corresponding
27 Source for a non-source form of such a combination shall include the
28 source code for the parts of OpenSSL used as well as that of the
29 covered work.
20*/ 30*/
21 31
22// TODO: EDNS0 option to increase dns mtu? 32// TODO: EDNS0 option to increase dns mtu?
23// TODO: re-write dns packet parsing/creation using a safe mem-buffer 33// TODO: re-write dns packet parsing/creation using a safe mem-buffer
24// to ensure no buffer overflows or similar problems. 34// to ensure no buffer overflows or similar problems.
… …
42#include <unistd.h> 52#include <unistd.h>
43#include <fcntl.h> 53#include <fcntl.h>
44 54
45#include <map> 55#include <map>
46 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
47#include <gmp.h> 58#include <gmp.h>
48 59
49#include "netcompat.h" 60#include "netcompat.h"
50 61
51#include "vpn.h" 62#include "vpn.h"
52 63
64#define MIN_POLL_INTERVAL 0.1 // poll at most this often when no data received
53#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
54#define ACTIVITY_INTERVAL 5.
55 66
56#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
57#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
58 69
59#define MAX_SEND_INTERVAL 2. // optimistic? 70#define MAX_SEND_INTERVAL 2. // optimistic?
… …
72#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
73 84
74#define RR_TYPE_A 1 85#define RR_TYPE_A 1
75#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
76#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
77#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
78 90
79#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
80 92
81#define CMD_IP_1 207 93#define CMD_IP_1 207
82#define CMD_IP_2 46 94#define CMD_IP_2 46
83#define CMD_IP_3 236 95#define CMD_IP_3 236
84#define CMD_IP_RST 29 96
85#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
86#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}
87 113
88// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
89struct charmap 115struct charmap
90{ 116{
91 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
105 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
106 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
107 133
108 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
109 { 135 {
136 char c = cmap [size];
137
110 enc [size] = cmap [size]; 138 enc [size] = c;
111 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;
112 } 144 }
113 145
114 assert (size < 256); 146 assert (size < 256);
115} 147}
116 148
… …
123{ 155{
124 charmap cmap; 156 charmap cmap;
125 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
126 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
127 159
128 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
129 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
130 162
131 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
132 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
133 165
134 basecoder (const char *cmap); 166 basecoder (const char *cmap);
135}; 167};
136 168
137basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
156 enc_len [len] = n; 188 enc_len [len] = n;
157 dec_len [n] = len; 189 dec_len [n] = len;
158 } 190 }
159} 191}
160 192
193unsigned int
161unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
162{ 195{
163 return enc_len [len]; 196 return enc_len [len];
164} 197}
165 198
199unsigned int
166unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
167{ 201{
168 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
169 --len; 203 --len;
170 204
171 return dec_len [len]; 205 return dec_len [len];
172} 206}
173 207
208unsigned int
174unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
175{ 210{
176 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
177 return 0; 212 return 0;
178 213
179 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
198 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
199 234
200 return elen; 235 return elen;
201} 236}
202 237
238unsigned int
203unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
204{ 240{
205 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
206 return 0; 242 return 0;
207 243
208 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
257 } 293 }
258 abort (); 294 abort ();
259} 295}
260#endif 296#endif
261 297
262//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
263//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
264static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
265//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
266static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
267 301
268///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
269 303
270#define HDRSIZE 6 304#define HDRSIZE 5
271 305
306inline void
272inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
273{ 308{
309 assert (clientid < 256);
310
274 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
275 312
276 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
277 clientid, 316 clientid,
278 (seqno >> 8) | (retry << 6),
279 seqno,
280 }; 317 };
281 318
282 assert (clientid < 256);
283
284 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
285} 320}
286 321
322inline void
287inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
288{ 324{
289 u8 hdr[3]; 325 u8 hdr[3];
290 326
291 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
292 328
293 clientid = hdr[0]; 329 clientid = hdr[2];
294 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
295} 331}
296 332
297///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
298 334
299struct byte_stream 335struct byte_stream
… …
325byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
326{ 362{
327 delete data; 363 delete data;
328} 364}
329 365
366void
330void byte_stream::remove (int count) 367byte_stream::remove (int count)
331{ 368{
332 if (count > fill) 369 if (count > fill)
333 assert (count <= fill); 370 assert (count <= fill);
334 371
335 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
336} 373}
337 374
375bool
338bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
339{ 377{
340 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
341 return false; 379 return false;
342 380
343 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
344 382
345 return true; 383 return true;
346} 384}
347 385
386bool
348bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
349{ 388{
350 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
351 return false; 390 return false;
352 391
353 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
… …
409 448
410struct dns_cfg 449struct dns_cfg
411{ 450{
412 static int next_uid; 451 static int next_uid;
413 452
414 u8 id1, id2, id3, id4; 453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
415 456
416 u8 version; 457 u8 version;
417 u8 flags; 458 u8 flags;
418 u8 rrtype; 459 u16 max_size;
460
461 u8 id1, id2, id3, id4;
462
463 u16 client;
419 u8 def_ttl; 464 u8 def_ttl;
465 u8 r0;
420 466
421 u16 client; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
422 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
423 471
424 u16 max_size;
425 u8 seq_cdc;
426 u8 req_cdc;
427
428 u8 rep_cdc;
429 u8 delay; // time in 0.01s units that the server may delay replying packets
430 u8 r3, r4;
431
432 u8 r5, r6, r7, r8; 472 u8 r1, r2, r3, r4;
433 473
434 void reset (int clientid); 474 void reset (int clientid);
435 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
436}; 477};
437 478
438int dns_cfg::next_uid; 479int dns_cfg::next_uid;
439 480
481void
440void dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
441{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
442 id1 = 'G'; 485 id1 = 'G';
443 id2 = 'V'; 486 id2 = 'V';
444 id3 = 'P'; 487 id3 = 'P';
445 id4 = 'E'; 488 id4 = 'E';
446 489
447 version = 1; 490 version = 2;
448 491
449 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
450 flags = 0; 493 flags = 0;
451 def_ttl = 0; 494 def_ttl = 0;
452 seq_cdc = 26; 495 syn_cdc = 26;
453 req_cdc = 62; 496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
454 rep_cdc = 0; 498 rep_cdc = 0;
455 max_size = htons (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
456 client = htons (clientid); 500 client = htons (clientid);
457 uid = next_uid++; 501 uid = ++next_uid;
458 delay = 0;
459 502
460 r3 = r4 = 0; 503 r0 = r1 = r2 = r3 = r4 = 0;
461 r4 = r5 = r6 = r7 = 0;
462}
463 504
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
464bool dns_cfg::valid () 526dns_cfg::valid ()
465{ 527{
466 // although the protocol itself allows for some configurability, 528 // although the protocol itself allows for some configurability,
467 // only the following encoding/decoding settings are implemented. 529 // only the following encoding/decoding settings are implemented.
468 return id1 == 'G' 530 return id1 == 'G'
469 && id2 == 'V' 531 && id2 == 'V'
470 && id3 == 'P' 532 && id3 == 'P'
471 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
472 && seq_cdc == 26 535 && syn_cdc == 26
473 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
474 && rep_cdc == 0 538 && rep_cdc == 0
475 && version == 1; 539 && chksum == get_chksum ();
476} 540}
477 541
478struct dns_packet : net_packet 542struct dns_packet : net_packet
479{ 543{
480 u16 id; 544 u16 id;
… …
484 u8 data [MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
485 549
486 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
487}; 551};
488 552
553int
489int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
490{ 555{
491 char *orig = data; 556 char *orig = data;
492 557
493 memset (data, 0, size); 558 memset (data, 0, size);
494 559
… …
520 return data - orig; 585 return data - orig;
521} 586}
522 587
523///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
524 589
590static
591u16 next_id ()
592{
525static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
526 594
527static u16 next_id ()
528{
529 if (!dns_id) 595 if (!dns_id)
530 dns_id = time (0); 596 dns_id = time (0);
531 597
532 // the simplest lsfr with periodicity 65535 i could find 598 // the simplest lsfr with periodicity 65535 i could find
533 dns_id = (dns_id << 1) 599 dns_id = (dns_id << 1)
… …
548 struct vpn *vpn; 614 struct vpn *vpn;
549 615
550 dns_cfg cfg; 616 dns_cfg cfg;
551 617
552 bool established; 618 bool established;
619 const basecoder *cdc;
553 620
554 tstamp last_received; 621 tstamp last_received;
555 tstamp last_sent; 622 tstamp last_sent;
556 double min_latency; 623 double min_latency;
557 double poll_interval, send_interval; 624 double poll_interval, send_interval;
… …
559 vector<dns_rcv *> rcvpq; 626 vector<dns_rcv *> rcvpq;
560 627
561 byte_stream rcvdq; int rcvseq; int repseq; 628 byte_stream rcvdq; int rcvseq; int repseq;
562 byte_stream snddq; int sndseq; 629 byte_stream snddq; int sndseq;
563 630
564 void time_cb (ev::timer &w, int revents); ev::timer tw; 631 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
565 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
566 636
567 dns_connection (connection *c); 637 dns_connection (connection *c);
568 ~dns_connection (); 638 ~dns_connection ();
569}; 639};
570 640
… …
588: dns (dns) 658: dns (dns)
589{ 659{
590 timeout = 0; 660 timeout = 0;
591 retry = 0; 661 retry = 0;
592 seqno = 0; 662 seqno = 0;
593 sent = ev::ev_now (); 663 sent = ev_now ();
594 stdhdr = false; 664 stdhdr = false;
595 665
596 pkt = new dns_packet; 666 pkt = new dns_packet;
597 667
598 pkt->id = next_id (); 668 pkt->id = next_id ();
… …
601dns_snd::~dns_snd () 671dns_snd::~dns_snd ()
602{ 672{
603 delete pkt; 673 delete pkt;
604} 674}
605 675
676static void
606static void append_domain (dns_packet &pkt, int &offs, const char *domain) 677append_domain (dns_packet &pkt, int &offs, const char *domain)
607{ 678{
608 // add tunnel domain 679 // add tunnel domain
609 for (;;) 680 for (;;)
610 { 681 {
611 const char *end = strchr (domain, '.'); 682 const char *end = strchr (domain, '.');
… …
624 695
625 domain = end + 1; 696 domain = end + 1;
626 } 697 }
627} 698}
628 699
700void
629void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 701dns_snd::gen_stream_req (int seqno, byte_stream &stream)
630{ 702{
631 stdhdr = true; 703 stdhdr = true;
632 this->seqno = seqno; 704 this->seqno = seqno;
633 705
634 timeout = ev::ev_now () + INITIAL_TIMEOUT; 706 timeout = ev_now () + INITIAL_TIMEOUT;
635 707
636 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 708 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
637 pkt->qdcount = htons (1); 709 pkt->qdcount = htons (1);
638 710
639 int offs = 6*2; 711 int offs = 6*2;
… …
642 // 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
643 715
644 char enc[256], *encp = enc; 716 char enc[256], *encp = enc;
645 encode_header (enc, THISNODE->id, seqno); 717 encode_header (enc, THISNODE->id, seqno);
646 718
647 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);
648 720
649 if (datalen > stream.size ()) 721 if (datalen > stream.size ())
650 datalen = stream.size (); 722 datalen = stream.size ();
651 723
652 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 724 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
653 stream.remove (datalen); 725 stream.remove (datalen);
654 726
655 while (enclen) 727 while (enclen)
656 { 728 {
657 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 729 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
672 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 744 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
673 745
674 pkt->len = offs; 746 pkt->len = offs;
675} 747}
676 748
749void
677void dns_snd::gen_syn_req () 750dns_snd::gen_syn_req ()
678{ 751{
679 timeout = ev::ev_now () + INITIAL_SYN_TIMEOUT; 752 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
680 753
681 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 754 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
682 pkt->qdcount = htons (1); 755 pkt->qdcount = htons (1);
683 756
684 int offs = 6 * 2; 757 int offs = 6 * 2;
… …
724 797
725dns_connection::dns_connection (connection *c) 798dns_connection::dns_connection (connection *c)
726: c (c) 799: c (c)
727, rcvdq (MAX_BACKLOG * 2) 800, rcvdq (MAX_BACKLOG * 2)
728, snddq (MAX_BACKLOG) 801, snddq (MAX_BACKLOG)
729, tw (this, &dns_connection::time_cb)
730{ 802{
803 tw.set<dns_connection, &dns_connection::time_cb> (this);
804
731 vpn = c->vpn; 805 vpn = c->vpn;
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 }
732 830
733 established = false; 831 established = false;
734 832
735 rcvseq = repseq = sndseq = 0; 833 rcvseq = repseq = sndseq = 0;
736 834
… …
738 poll_interval = 0.5; // starting here 836 poll_interval = 0.5; // starting here
739 send_interval = 0.5; // starting rate 837 send_interval = 0.5; // starting rate
740 min_latency = INITIAL_TIMEOUT; 838 min_latency = INITIAL_TIMEOUT;
741} 839}
742 840
743dns_connection::~dns_connection () 841void
842dns_connection::set_cfg ()
744{ 843{
745 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 844 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
746 i != rcvpq.end ();
747 ++i)
748 delete *i;
749} 845}
750 846
847void
751void dns_connection::receive_rep (dns_rcv *r) 848dns_connection::receive_rep (dns_rcv *r)
752{ 849{
753 if (r->datalen) 850 if (r->datalen)
754 { 851 {
755 last_received = ev::ev_now (); 852 last_received = ev_now ();
756 tw (); 853 tw ();
757 854
758 poll_interval = send_interval; 855 poll_interval = send_interval;
759 } 856 }
760 else 857 else
… …
789 886
790 rcvseq = (rcvseq + 1) & SEQNO_MASK; 887 rcvseq = (rcvseq + 1) & SEQNO_MASK;
791 888
792 if (!rcvdq.put (r->data, r->datalen)) 889 if (!rcvdq.put (r->data, r->datalen))
793 { 890 {
891 // MUST never overflow, can be caused by data corruption, TODO
794 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 892 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
795 abort (); // MUST never overflow, can be caused by data corruption, TODO 893 reset ();
894 return;
796 } 895 }
797 896
798 while (vpn_packet *pkt = rcvdq.get ()) 897 while (vpn_packet *pkt = rcvdq.get ())
799 { 898 {
800 sockinfo si; 899 sockinfo si;
801 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;
802 901
803 vpn->recv_vpn_packet (pkt, si); 902 vpn->recv_vpn_packet (pkt, si);
804
805 delete pkt; 903 delete pkt;
806 } 904 }
807 905
808 // check for further packets 906 // check for further packets
809 goto redo; 907 goto redo;
… …
852 { 950 {
853 // correct class, domain: parse 951 // correct class, domain: parse
854 int client, seqno; 952 int client, seqno;
855 decode_header (qname, client, seqno); 953 decode_header (qname, client, seqno);
856 954
857 u8 data[MAXSIZE];
858 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
859
860 if (0 < client && client <= conns.size ()) 955 if (0 < client && client <= conns.size ())
861 { 956 {
862 connection *c = conns [client - 1]; 957 connection *c = conns [client - 1];
863 dns_connection *dns = c->dns; 958 dns_connection *dns = c->dns;
864 dns_rcv *rcv; 959 dns_rcv *rcv;
865 960
866 if (dns) 961 if (dns)
867 { 962 {
963 u8 data[MAXSIZE];
964 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
965
868 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 (); )
869 if (SEQNO_EQ ((*i)->seqno, seqno)) 967 if (SEQNO_EQ ((*i)->seqno, seqno))
870 { 968 {
871 // already seen that request: simply reply with the cached reply 969 // already seen that request: simply reply with the cached reply
872 dns_rcv *r = *i; 970 dns_rcv *r = *i;
… …
973 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
974 pkt [offs++] = 0; pkt [offs++] = 0; 1072 pkt [offs++] = 0; pkt [offs++] = 0;
975 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1073 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
976 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1074 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
977 1075
978 slog (L_INFO, _("DNS: client %d connects"), client);
979
980 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;
981 pkt [offs++] = CMD_IP_REJ; 1077 pkt [offs++] = CMD_IP_REJ;
982 1078
983 if (0 < client && client <= conns.size ()) 1079 if (0 < client && client <= conns.size ())
984 { 1080 {
985 connection *c = conns [client - 1]; 1081 connection *c = conns [client - 1];
986 1082
987 if (cfg.valid ()) 1083 if (cfg.valid ())
988 { 1084 {
989 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));
990 1090
991 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
992 c->dns = new dns_connection (c); 1096 c->dns = new dns_connection (c);
993 c->dns->cfg = cfg; 1097 c->dns->cfg = cfg;
1098 c->dns->set_cfg ();
994 } 1099 }
995 } 1100 }
996 } 1101 }
997 } 1102 }
998 1103
… …
1018 dns_connection *dns = (*i)->dns; 1123 dns_connection *dns = (*i)->dns;
1019 connection *c = dns->c; 1124 connection *c = dns->c;
1020 int seqno = (*i)->seqno; 1125 int seqno = (*i)->seqno;
1021 u8 data[MAXSIZE], *datap = data; 1126 u8 data[MAXSIZE], *datap = data;
1022 //printf ("rcv pkt %x\n", seqno);//D 1127 //printf ("rcv pkt %x\n", seqno);//D
1128 bool back_off = (*i)->retry;
1023 1129
1024 if ((*i)->retry) 1130 if (back_off)
1025 { 1131 {
1026 dns->send_interval *= 1.01; 1132 dns->send_interval *= 1.01;
1027 if (dns->send_interval > MAX_SEND_INTERVAL) 1133 if (dns->send_interval > MAX_SEND_INTERVAL)
1028 dns->send_interval = MAX_SEND_INTERVAL; 1134 dns->send_interval = MAX_SEND_INTERVAL;
1029 } 1135 }
… …
1032#if 0 1138#if 0
1033 dns->send_interval *= 0.999; 1139 dns->send_interval *= 0.999;
1034#endif 1140#endif
1035 // the latency surely puts an upper bound on 1141 // the latency surely puts an upper bound on
1036 // the minimum send interval 1142 // the minimum send interval
1037 double latency = ev::ev_now () - (*i)->sent; 1143 double latency = ev_now () - (*i)->sent;
1038 1144
1039 if (latency < dns->min_latency) 1145 if (latency < dns->min_latency)
1040 dns->min_latency = latency; 1146 dns->min_latency = latency;
1041 1147
1042 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) 1148 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
… …
1069 ttl |= pkt [offs++] << 16; 1175 ttl |= pkt [offs++] << 16;
1070 ttl |= pkt [offs++] << 8; 1176 ttl |= pkt [offs++] << 8;
1071 ttl |= pkt [offs++]; 1177 ttl |= pkt [offs++];
1072 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1178 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1073 1179
1074 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1180 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1075 { 1181 {
1076 if (rdlen <= MAXSIZE - offs) 1182 if (rdlen <= MAXSIZE - offs)
1077 { 1183 {
1078 // decode bytes, finally 1184 // decode bytes, finally
1079 1185
… …
1105 { 1211 {
1106 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1212 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1107 1213
1108 if (ip [3] == CMD_IP_RST) 1214 if (ip [3] == CMD_IP_RST)
1109 { 1215 {
1110 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1216 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1111 1217
1112 delete dns; c->dns = 0; 1218 dns->reset ();
1113
1114 return; 1219 return;
1115 } 1220 }
1116 else if (ip [3] == CMD_IP_SYN) 1221 else if (ip [3] == CMD_IP_SYN)
1117 { 1222 {
1118 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1223 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1119 dns->established = true; 1224 dns->established = true;
1120 } 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 }
1121 else if (ip [3] == CMD_IP_REJ) 1241 else if (ip [3] == CMD_IP_REJ)
1122 { 1242 {
1123 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."));
1124 abort (); 1244 dns->tw.start (60.);
1125 } 1245 }
1126 else 1246 else
1247 {
1127 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 }
1128 } 1251 }
1129 else 1252 else
1130 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"),
1131 ip [0], ip [1], ip [2], ip [3]); 1254 ip [0], ip [1], ip [2], ip [3]);
1132 1255
… …
1150 } 1273 }
1151 1274
1152 // todo: pkt now used 1275 // todo: pkt now used
1153 if (datap) 1276 if (datap)
1154 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 }
1155 1288
1156 break; 1289 break;
1157 } 1290 }
1158} 1291}
1159 1292
… …
1200 1333
1201 // always return true even if the buffer overflows 1334 // always return true even if the buffer overflows
1202 return true; 1335 return true;
1203} 1336}
1204 1337
1205void
1206connection::dnsv4_reset_connection ()
1207{
1208 //delete dns; dns = 0; //TODO
1209}
1210
1211#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1338#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1212 1339
1213void 1340void
1214dns_connection::time_cb (ev::timer &w, int revents) 1341dns_connection::time_cb (ev::timer &w, int revents)
1215{ 1342{
… …
1225 i != vpn->dns_sndpq.end (); 1352 i != vpn->dns_sndpq.end ();
1226 ++i) 1353 ++i)
1227 { 1354 {
1228 dns_snd *r = *i; 1355 dns_snd *r = *i;
1229 1356
1230 if (r->timeout <= ev::ev_now ()) 1357 if (r->timeout <= ev_now ())
1231 { 1358 {
1232 if (!send) 1359 if (!send)
1233 { 1360 {
1234 send = r; 1361 send = r;
1235 1362
1236 r->retry++; 1363 r->retry++;
1237 r->timeout = ev::ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); 1364 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1238 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev::ev_now ());//D 1365 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1239 1366
1240 // the following code changes the query section a bit, forcing 1367 // the following code changes the query section a bit, forcing
1241 // the forwarder to generate a new request 1368 // the forwarder to generate a new request
1242 if (r->stdhdr) 1369 if (r->stdhdr)
1243 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1370 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
… …
1256 if (vpn->dns_sndpq.empty ()) 1383 if (vpn->dns_sndpq.empty ())
1257 { 1384 {
1258 send = new dns_snd (this); 1385 send = new dns_snd (this);
1259 1386
1260 cfg.reset (THISNODE->id); 1387 cfg.reset (THISNODE->id);
1388 set_cfg ();
1261 send->gen_syn_req (); 1389 send->gen_syn_req ();
1262 } 1390 }
1263 } 1391 }
1264 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1392 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1265 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1393 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1266 { 1394 {
1267 if (last_sent + send_interval <= ev::ev_now ()) 1395 if (last_sent + send_interval <= ev_now ())
1268 { 1396 {
1269 //printf ("sending data request etc.\n"); //D 1397 //printf ("sending data request etc.\n"); //D
1270 if (!snddq.empty () || last_received + 1. > ev::ev_now ()) 1398 if (!snddq.empty () || last_received + 1. > ev_now ())
1271 { 1399 {
1272 poll_interval = send_interval; 1400 poll_interval = send_interval;
1273 NEXT (ev::ev_now () + send_interval); 1401 NEXT (ev_now () + send_interval);
1274 } 1402 }
1275 1403
1276 send = new dns_snd (this); 1404 send = new dns_snd (this);
1277 send->gen_stream_req (sndseq, snddq); 1405 send->gen_stream_req (sndseq, snddq);
1278 send->timeout = ev::ev_now () + min_latency * conf.dns_timeout_factor; 1406 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1279 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev::ev_now (), min_latency, conf.dns_timeout_factor);//D 1407 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1280 1408
1281 sndseq = (sndseq + 1) & SEQNO_MASK; 1409 sndseq = (sndseq + 1) & SEQNO_MASK;
1282 } 1410 }
1283 else 1411 else
1284 NEXT (last_sent + send_interval); 1412 NEXT (last_sent + send_interval);
… …
1288 vpn->dns_sndpq.push_back (send); 1416 vpn->dns_sndpq.push_back (send);
1289 } 1417 }
1290 1418
1291 if (send) 1419 if (send)
1292 { 1420 {
1293 last_sent = ev::ev_now (); 1421 last_sent = ev_now ();
1294 sendto (vpn->dnsv4_fd, 1422 sendto (vpn->dnsv4_fd,
1295 send->pkt->at (0), send->pkt->len, 0, 1423 send->pkt->at (0), send->pkt->len, 0,
1296 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1424 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1297 } 1425 }
1298 1426
1299 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1427 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1300 poll_interval, send_interval, next - ev::ev_now (), 1428 poll_interval, send_interval, next - ev_now (),
1301 vpn->dns_sndpq.size (), snddq.size (), 1429 vpn->dns_sndpq.size (), snddq.size (),
1302 rcvpq.size ()); 1430 rcvpq.size ());
1303 1431
1304 // TODO: no idea when this happens, but when next < ev::ev_now (), we have a problem 1432 // TODO: no idea when this happens, but when next < ev_now (), we have a problem
1305 // doesn't seem to happen anymore 1433 // doesn't seem to happen anymore
1306 if (next < ev::ev_now () + 0.001) 1434 if (next < ev_now () + 0.001)
1307 next = ev::ev_now () + 0.1; 1435 next = ev_now () + 0.1;
1308 1436
1309 w.start (next - ev::ev_now ()); 1437 w.start (next - ev_now ());
1310} 1438}
1311 1439
1312#endif 1440#endif
1313 1441

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