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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC vs.
Revision 1.50 by root, Sun Mar 6 13:49:50 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) 2003-2008 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. 59 Temple Place, Suite 330, Boston, MA 02111-1307 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*/
31
32// TODO: EDNS0 option to increase dns mtu?
33// TODO: re-write dns packet parsing/creation using a safe mem-buffer
34// to ensure no buffer overflows or similar problems.
21 35
22#include "config.h" 36#include "config.h"
23 37
24#if ENABLE_DNS 38#if ENABLE_DNS
25 39
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 40// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27// it's a hack, use only in emergency situations please. 41// it's a hack, use only in emergency situations please.
28 42
29#include <cstring> 43#include <cstring>
44#include <cassert>
30 45
31#include <sys/types.h> 46#include <sys/types.h>
32#include <sys/socket.h> 47#include <sys/socket.h>
33#include <sys/wait.h> 48#include <sys/wait.h>
34#include <sys/uio.h> 49#include <sys/uio.h>
… …
37#include <unistd.h> 52#include <unistd.h>
38#include <fcntl.h> 53#include <fcntl.h>
39 54
40#include <map> 55#include <map>
41 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
42#include <gmp.h> 58#include <gmp.h>
43 59
44#include "netcompat.h" 60#include "netcompat.h"
45 61
46#include "vpn.h" 62#include "vpn.h"
47 63
48#define MIN_POLL_INTERVAL .02 // how often to poll minimally when the server has data
49#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data 64#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
50#define ACTIVITY_INTERVAL 5. 65#define ACTIVITY_INTERVAL 5.
51 66
52#define INITIAL_TIMEOUT 1. // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
53#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54 69
55#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
56#define MAX_SEND_INTERVAL 0.5 // optimistic? 70#define MAX_SEND_INTERVAL 2. // optimistic?
57 71
58#define MAX_OUTSTANDING 40 // max. outstanding requests
59#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
60#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE 73#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
61 74
62#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well 75#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well
63// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
64// every two request bytes less give room for one reply byte 77// every request byte less give room for two reply bytes
65 78
66#define SEQNO_MASK 0xffff 79#define SEQNO_MASK 0x3fff
67#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
68 81
69#define MAX_LBL_SIZE 63 82#define MAX_LBL_SIZE 63
70#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
71 84
72#define RR_TYPE_A 1 85#define RR_TYPE_A 1
73#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
74#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
75#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
76 90
77#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
78 92
79#define CMD_IP_1 207 93#define CMD_IP_1 207
… …
103 memset (enc, (char) 0, 256); 117 memset (enc, (char) 0, 256);
104 memset (dec, (char)INVALID, 256); 118 memset (dec, (char)INVALID, 256);
105 119
106 for (size = 0; cmap [size]; size++) 120 for (size = 0; cmap [size]; size++)
107 { 121 {
122 char c = cmap [size];
123
108 enc [size] = cmap [size]; 124 enc [size] = c;
109 dec [(u8)enc [size]] = size; 125 dec [(u8)c] = size;
126
127 // allow lowercase/uppercase aliases if possible
128 if (c >= 'A' && c <= 'Z' && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size;
129 if (c >= 'a' && c <= 'z' && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size;
110 } 130 }
111 131
112 assert (size < 256); 132 assert (size < 256);
113} 133}
114 134
… …
154 enc_len [len] = n; 174 enc_len [len] = n;
155 dec_len [n] = len; 175 dec_len [n] = len;
156 } 176 }
157} 177}
158 178
179unsigned int
159unsigned int basecoder::encode_len (unsigned int len) 180basecoder::encode_len (unsigned int len)
160{ 181{
161 return enc_len [len]; 182 return enc_len [len];
162} 183}
163 184
185unsigned int
164unsigned int basecoder::decode_len (unsigned int len) 186basecoder::decode_len (unsigned int len)
165{ 187{
166 while (len && !dec_len [len]) 188 while (len && !dec_len [len])
167 --len; 189 --len;
168 190
169 return dec_len [len]; 191 return dec_len [len];
170} 192}
171 193
194unsigned int
172unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 195basecoder::encode (char *dst, u8 *src, unsigned int len)
173{ 196{
174 if (!len || len > MAX_DEC_LEN) 197 if (!len || len > MAX_DEC_LEN)
175 return 0; 198 return 0;
176 199
177 int elen = encode_len (len); 200 int elen = encode_len (len);
… …
196 *dst++ = cmap.encode [dst_ [i]]; 219 *dst++ = cmap.encode [dst_ [i]];
197 220
198 return elen; 221 return elen;
199} 222}
200 223
224unsigned int
201unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 225basecoder::decode (u8 *dst, char *src, unsigned int len)
202{ 226{
203 if (!len || len > MAX_ENC_LEN) 227 if (!len || len > MAX_ENC_LEN)
204 return 0; 228 return 0;
205 229
206 u8 src_ [MAX_ENC_LEN]; 230 u8 src_ [MAX_ENC_LEN];
… …
264static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 288static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
265 289
266///////////////////////////////////////////////////////////////////////////// 290/////////////////////////////////////////////////////////////////////////////
267 291
268#define HDRSIZE 6 292#define HDRSIZE 6
269 293
294inline void
270inline void encode_header (char *data, int clientid, int seqno) 295encode_header (char *data, int clientid, int seqno, int retry = 0)
271{ 296{
272 u8 hdr[3] = { clientid, seqno >> 8, seqno }; 297 seqno &= SEQNO_MASK;
298
299 u8 hdr[3] = {
300 clientid,
301 (seqno >> 8) | (retry << 6),
302 seqno,
303 };
273 304
274 assert (clientid < 256); 305 assert (clientid < 256);
275 306
276 cdc26.encode (data, hdr, 3); 307 cdc26.encode (data, hdr, 3);
277} 308}
278 309
310inline void
279inline void decode_header (char *data, int &clientid, int &seqno) 311decode_header (char *data, int &clientid, int &seqno)
280{ 312{
281 u8 hdr[3]; 313 u8 hdr[3];
282 314
283 cdc26.decode (hdr, data, HDRSIZE); 315 cdc26.decode (hdr, data, HDRSIZE);
284 316
285 clientid = hdr[0]; 317 clientid = hdr[0];
286 seqno = (hdr[1] << 8) | hdr[2]; 318 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK;
287} 319}
288 320
289///////////////////////////////////////////////////////////////////////////// 321/////////////////////////////////////////////////////////////////////////////
290 322
291struct byte_stream 323struct byte_stream
… …
317byte_stream::~byte_stream () 349byte_stream::~byte_stream ()
318{ 350{
319 delete data; 351 delete data;
320} 352}
321 353
354void
322void byte_stream::remove (int count) 355byte_stream::remove (int count)
323{ 356{
324 if (count > fill) 357 if (count > fill)
325 abort (); 358 assert (count <= fill);
326 359
327 memmove (data, data + count, fill -= count); 360 memmove (data, data + count, fill -= count);
328} 361}
329 362
363bool
330bool byte_stream::put (u8 *data, unsigned int datalen) 364byte_stream::put (u8 *data, unsigned int datalen)
331{ 365{
332 if (maxsize - fill < datalen) 366 if (maxsize - fill < datalen)
333 return false; 367 return false;
334 368
335 memcpy (this->data + fill, data, datalen); fill += datalen; 369 memcpy (this->data + fill, data, datalen); fill += datalen;
336 370
337 return true; 371 return true;
338} 372}
339 373
374bool
340bool byte_stream::put (vpn_packet *pkt) 375byte_stream::put (vpn_packet *pkt)
341{ 376{
342 if (maxsize - fill < pkt->len + 2) 377 if (maxsize - fill < pkt->len + 2)
343 return false; 378 return false;
344 379
345 data [fill++] = pkt->len >> 8; 380 data [fill++] = pkt->len >> 8;
… …
350 return true; 385 return true;
351} 386}
352 387
353vpn_packet *byte_stream::get () 388vpn_packet *byte_stream::get ()
354{ 389{
390 unsigned int len;
391
392 for (;;)
393 {
355 unsigned int len = (data [0] << 8) | data [1]; 394 len = (data [0] << 8) | data [1];
356 395
357 if (len > MAXSIZE && fill >= 2) 396 if (len <= MAXSIZE || fill < 2)
358 abort (); // TODO handle this gracefully, connection reset 397 break;
359 398
399 // TODO: handle this better than skipping, e.g. by reset
400 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
401 remove (1);
402 }
403
360 if (fill < len + 2) 404 if (fill < len + 2)
361 return 0; 405 return 0;
362 406
363 vpn_packet *pkt = new vpn_packet; 407 vpn_packet *pkt = new vpn_packet;
364 408
… …
393struct dns_cfg 437struct dns_cfg
394{ 438{
395 static int next_uid; 439 static int next_uid;
396 440
397 u8 id1, id2, id3, id4; 441 u8 id1, id2, id3, id4;
442
398 u8 version; 443 u8 version;
444 u8 flags;
399 u8 rrtype; 445 u8 rrtype;
400 u8 flags;
401 u8 def_ttl; 446 u8 def_ttl;
402 u8 rcv_cdc; 447
403 u8 snd_cdc;
404 u16 max_size;
405 u16 client; 448 u16 client;
406 u16 uid; // to make request unique 449 u16 uid; // to make request unique
407 450
408 u8 reserved[8]; 451 u16 max_size;
452 u8 seq_cdc;
453 u8 req_cdc;
454
455 u8 rep_cdc;
456 u8 delay; // time in 0.01s units that the server may delay replying packets
457 u8 r3, r4;
458
459 u8 r5, r6, r7, r8;
409 460
410 void reset (int clientid); 461 void reset (int clientid);
411 bool valid (); 462 bool valid ();
412}; 463};
413 464
414int dns_cfg::next_uid; 465int dns_cfg::next_uid;
415 466
467void
416void dns_cfg::reset (int clientid) 468dns_cfg::reset (int clientid)
417{ 469{
418 id1 = 'G'; 470 id1 = 'G';
419 id2 = 'V'; 471 id2 = 'V';
420 id3 = 'P'; 472 id3 = 'P';
421 id4 = 'E'; 473 id4 = 'E';
… …
423 version = 1; 475 version = 1;
424 476
425 rrtype = RR_TYPE_TXT; 477 rrtype = RR_TYPE_TXT;
426 flags = 0; 478 flags = 0;
427 def_ttl = 0; 479 def_ttl = 0;
480 seq_cdc = 26;
481 req_cdc = 62;
428 rcv_cdc = 0; 482 rep_cdc = 0;
429 snd_cdc = 62;
430 max_size = ntohs (MAX_PKT_SIZE); 483 max_size = htons (MAX_PKT_SIZE);
431 client = ntohs (clientid); 484 client = htons (clientid);
432 uid = next_uid++; 485 uid = next_uid++;
486 delay = 0;
433 487
434 memset (reserved, 0, 8); 488 r3 = r4 = 0;
489 r4 = r5 = r6 = r7 = 0;
435} 490}
436 491
492bool
437bool dns_cfg::valid () 493dns_cfg::valid ()
438{ 494{
495 // although the protocol itself allows for some configurability,
496 // only the following encoding/decoding settings are implemented.
439 return id1 == 'G' 497 return id1 == 'G'
440 && id2 == 'V' 498 && id2 == 'V'
441 && id3 == 'P' 499 && id3 == 'P'
442 && id4 == 'E' 500 && id4 == 'E'
501 && seq_cdc == 26
502 && req_cdc == 62
503 && rep_cdc == 0
443 && version == 1 504 && version == 1;
444 && flags == 0
445 && rcv_cdc == 0
446 && snd_cdc == 62
447 && max_size == ntohs (MAX_PKT_SIZE);
448} 505}
449 506
450struct dns_packet : net_packet 507struct dns_packet : net_packet
451{ 508{
452 u16 id; 509 u16 id;
453 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 510 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
454 u16 qdcount, ancount, nscount, arcount; 511 u16 qdcount, ancount, nscount, arcount;
455 512
456 u8 data[MAXSIZE - 6 * 2]; 513 u8 data [MAXSIZE - 6 * 2];
457 514
458 int decode_label (char *data, int size, int &offs); 515 int decode_label (char *data, int size, int &offs);
459}; 516};
460 517
518int
461int dns_packet::decode_label (char *data, int size, int &offs) 519dns_packet::decode_label (char *data, int size, int &offs)
462{ 520{
463 char *orig = data; 521 char *orig = data;
464 522
465 memset (data, 0, size); 523 memset (data, 0, size);
466 524
… …
492 return data - orig; 550 return data - orig;
493} 551}
494 552
495///////////////////////////////////////////////////////////////////////////// 553/////////////////////////////////////////////////////////////////////////////
496 554
497struct dns_snd 555static
556u16 next_id ()
498{ 557{
499 dns_packet *pkt;
500 tstamp timeout, sent;
501 int retry;
502 struct dns_connection *dns;
503 int seqno;
504
505 void gen_stream_req (int seqno, byte_stream &stream);
506 void gen_syn_req (const dns_cfg &cfg);
507
508 dns_snd (dns_connection *dns);
509 ~dns_snd ();
510};
511
512static u16 dns_id = 12098; // TODO: should be per-vpn 558 static u16 dns_id = 0; // TODO: should be per-vpn
513 559
514static u16 next_id () 560 if (!dns_id)
515{ 561 dns_id = time (0);
562
516 // the simplest lsfr with periodicity 65535 i could find 563 // the simplest lsfr with periodicity 65535 i could find
517 dns_id = (dns_id << 1) 564 dns_id = (dns_id << 1)
518 | (((dns_id >> 1) 565 | (((dns_id >> 1)
519 ^ (dns_id >> 2) 566 ^ (dns_id >> 2)
520 ^ (dns_id >> 4) 567 ^ (dns_id >> 4)
521 ^ (dns_id >> 15)) & 1); 568 ^ (dns_id >> 15)) & 1);
522 569
523 return dns_id; 570 return dns_id;
524} 571}
525 572
573struct dns_rcv;
574struct dns_snd;
575
576struct dns_connection
577{
578 connection *c;
579 struct vpn *vpn;
580
581 dns_cfg cfg;
582
583 bool established;
584
585 tstamp last_received;
586 tstamp last_sent;
587 double min_latency;
588 double poll_interval, send_interval;
589
590 vector<dns_rcv *> rcvpq;
591
592 byte_stream rcvdq; int rcvseq; int repseq;
593 byte_stream snddq; int sndseq;
594
595 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
596 void receive_rep (dns_rcv *r);
597
598 dns_connection (connection *c);
599 ~dns_connection ();
600};
601
602struct dns_snd
603{
604 dns_packet *pkt;
605 tstamp timeout, sent;
606 int retry;
607 struct dns_connection *dns;
608 int seqno;
609 bool stdhdr;
610
611 void gen_stream_req (int seqno, byte_stream &stream);
612 void gen_syn_req ();
613
614 dns_snd (dns_connection *dns);
615 ~dns_snd ();
616};
617
526dns_snd::dns_snd (dns_connection *dns) 618dns_snd::dns_snd (dns_connection *dns)
527: dns (dns) 619: dns (dns)
528{ 620{
529 timeout = 0; 621 timeout = 0;
530 retry = 0; 622 retry = 0;
531 seqno = 0; 623 seqno = 0;
532 sent = NOW; 624 sent = ev_now ();
625 stdhdr = false;
533 626
534 pkt = new dns_packet; 627 pkt = new dns_packet;
535 628
536 pkt->id = next_id (); 629 pkt->id = next_id ();
537} 630}
… …
539dns_snd::~dns_snd () 632dns_snd::~dns_snd ()
540{ 633{
541 delete pkt; 634 delete pkt;
542} 635}
543 636
637static void
544static void append_domain (dns_packet &pkt, int &offs, const char *domain) 638append_domain (dns_packet &pkt, int &offs, const char *domain)
545{ 639{
546 // add tunnel domain 640 // add tunnel domain
547 for (;;) 641 for (;;)
548 { 642 {
549 const char *end = strchr (domain, '.'); 643 const char *end = strchr (domain, '.');
… …
562 656
563 domain = end + 1; 657 domain = end + 1;
564 } 658 }
565} 659}
566 660
661void
567void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 662dns_snd::gen_stream_req (int seqno, byte_stream &stream)
568{ 663{
664 stdhdr = true;
569 this->seqno = seqno; 665 this->seqno = seqno;
570 666
571 timeout = NOW + INITIAL_TIMEOUT; 667 timeout = ev_now () + INITIAL_TIMEOUT;
572 668
573 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 669 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
574 pkt->qdcount = htons (1); 670 pkt->qdcount = htons (1);
575 671
576 int offs = 6*2; 672 int offs = 6*2;
577 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 673 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
578 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 674 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
579 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 675 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
580 676
581 char enc[256], *encp = enc; 677 char enc[256], *encp = enc;
582 encode_header (enc, THISNODE->id, seqno); 678 encode_header (enc, THISNODE->id, seqno);
… …
600 encp += lbllen; 696 encp += lbllen;
601 697
602 enclen -= lbllen; 698 enclen -= lbllen;
603 } 699 }
604 700
605 append_domain (*pkt, offs, THISNODE->domain); 701 append_domain (*pkt, offs, dns->c->conf->domain);
606 702
607 (*pkt)[offs++] = 0; 703 (*pkt)[offs++] = 0;
608 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 704 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
609 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 705 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
610 706
611 pkt->len = offs; 707 pkt->len = offs;
612} 708}
613 709
614void dns_snd::gen_syn_req (const dns_cfg &cfg) 710void
711dns_snd::gen_syn_req ()
615{ 712{
616 timeout = NOW + INITIAL_SYN_TIMEOUT; 713 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
617 714
618 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 715 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
619 pkt->qdcount = htons (1); 716 pkt->qdcount = htons (1);
620 717
621 int offs = 6*2; 718 int offs = 6 * 2;
622 719
623 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); 720 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg));
624 721
625 assert (elen <= MAX_LBL_SIZE); 722 assert (elen <= MAX_LBL_SIZE);
626 723
627 (*pkt)[offs] = elen; 724 (*pkt)[offs] = elen;
628 offs += elen + 1; 725 offs += elen + 1;
629 append_domain (*pkt, offs, THISNODE->domain); 726 append_domain (*pkt, offs, dns->c->conf->domain);
630 727
631 (*pkt)[offs++] = 0; 728 (*pkt)[offs++] = 0;
632 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 729 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
633 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 730 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
634 731
… …
657 delete pkt; 754 delete pkt;
658} 755}
659 756
660///////////////////////////////////////////////////////////////////////////// 757/////////////////////////////////////////////////////////////////////////////
661 758
662struct dns_connection
663{
664 connection *c;
665 struct vpn *vpn;
666
667 dns_cfg cfg;
668
669 bool established;
670
671 tstamp last_received;
672 tstamp last_sent;
673 double poll_interval, send_interval;
674
675 vector<dns_rcv *> rcvpq;
676
677 byte_stream rcvdq; int rcvseq;
678 byte_stream snddq; int sndseq;
679
680 void time_cb (time_watcher &w); time_watcher tw;
681 void receive_rep (dns_rcv *r);
682
683 dns_connection (connection *c);
684 ~dns_connection ();
685};
686
687dns_connection::dns_connection (connection *c) 759dns_connection::dns_connection (connection *c)
688: c (c) 760: c (c)
689, rcvdq (MAX_BACKLOG * 2) 761, rcvdq (MAX_BACKLOG * 2)
690, snddq (MAX_BACKLOG * 2) 762, snddq (MAX_BACKLOG)
691, tw (this, &dns_connection::time_cb)
692{ 763{
764 tw.set<dns_connection, &dns_connection::time_cb> (this);
765
693 vpn = c->vpn; 766 vpn = c->vpn;
694 767
695 established = false; 768 established = false;
696 769
697 rcvseq = sndseq = 0; 770 rcvseq = repseq = sndseq = 0;
698 771
699 last_sent = last_received = 0; 772 last_sent = last_received = 0;
700 poll_interval = MIN_POLL_INTERVAL; 773 poll_interval = 0.5; // starting here
701 send_interval = 0.2; // starting rate 774 send_interval = 0.5; // starting rate
775 min_latency = INITIAL_TIMEOUT;
702} 776}
703 777
704dns_connection::~dns_connection () 778dns_connection::~dns_connection ()
705{ 779{
706 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 780 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
707 i != rcvpq.end (); 781 i != rcvpq.end ();
708 ++i) 782 ++i)
709 delete *i; 783 delete *i;
710} 784}
711 785
786void
712void dns_connection::receive_rep (dns_rcv *r) 787dns_connection::receive_rep (dns_rcv *r)
713{ 788{
714 if (r->datalen) 789 if (r->datalen)
715 { 790 {
716 last_received = NOW; 791 last_received = ev_now ();
717 tw.trigger (); 792 tw ();
718 793
719 poll_interval = send_interval; 794 poll_interval = send_interval;
720 } 795 }
721 else 796 else
722 { 797 {
723 poll_interval *= 1.1; 798 poll_interval *= 1.5;
799
724 if (poll_interval > MAX_POLL_INTERVAL) 800 if (poll_interval > MAX_POLL_INTERVAL)
725 poll_interval = MAX_POLL_INTERVAL; 801 poll_interval = MAX_POLL_INTERVAL;
726 } 802 }
727 803
728 rcvpq.push_back (r); 804 rcvpq.push_back (r);
… …
731 807
732 // find next packet 808 // find next packet
733 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 809 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
734 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 810 if (SEQNO_EQ (rcvseq, (*i)->seqno))
735 { 811 {
812 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
736 // enter the packet into our input stream 813 // enter the packet into our input stream
737 r = *i; 814 r = *i;
738 815
739 // remove the oldest packet, look forward, as it's oldest first 816 // remove the oldest packet, look forward, as it's oldest first
740 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 817 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
741 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 818 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
742 { 819 {
820 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
743 delete *j; 821 delete *j;
744 rcvpq.erase (j); 822 rcvpq.erase (j);
745 break; 823 break;
746 } 824 }
747 825
748 rcvseq = (rcvseq + 1) & SEQNO_MASK; 826 rcvseq = (rcvseq + 1) & SEQNO_MASK;
749 827
750 if (!rcvdq.put (r->data, r->datalen)) 828 if (!rcvdq.put (r->data, r->datalen))
829 {
751 abort (); // MUST never overflow, can be caused by data corruption, TODO 830 // MUST never overflow, can be caused by data corruption, TODO
831 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
832 c->dnsv4_reset_connection ();
833 return;
834 }
752 835
753 while (vpn_packet *pkt = rcvdq.get ()) 836 while (vpn_packet *pkt = rcvdq.get ())
754 { 837 {
755 sockinfo si; 838 sockinfo si;
756 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 839 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
757 840
758 vpn->recv_vpn_packet (pkt, si); 841 vpn->recv_vpn_packet (pkt, si);
759
760 delete pkt; 842 delete pkt;
761 } 843 }
762 844
763 // check for further packets 845 // check for further packets
764 goto redo; 846 goto redo;
… …
775 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 857 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
776 858
777 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 859 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
778 && pkt.qdcount == htons (1)) 860 && pkt.qdcount == htons (1))
779 { 861 {
780 char qname[MAXSIZE]; 862 char qname [MAXSIZE];
781 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 863 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
782 864
783 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 865 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
784 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 866 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
785 867
786 pkt.qdcount = htons (1); 868 pkt.qdcount = htons (1);
787 pkt.ancount = 0; 869 pkt.ancount = 0;
788 pkt.nscount = 0; // should be self, as other nameservers reply like this 870 pkt.nscount = 0; // should be self, as other nameservers reply like this
789 pkt.arcount = 0; // a record for self, as other nameservers reply like this 871 pkt.arcount = 0; // a record for self, as other nameservers reply like this
790 872
791 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_NXDOMAIN); 873 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_SERVFAIL);
792 874
793 int dlen = strlen (THISNODE->domain); 875 int dlen = strlen (THISNODE->domain);
794 876
795 if (qclass == RR_CLASS_IN 877 if (qclass == RR_CLASS_IN
796 && qlen > dlen + 1 878 && qlen > dlen + 1
797 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 879 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
798 { 880 {
799 // now generate reply 881 // now generate reply
800 pkt.ancount = htons (1); // one answer RR 882 pkt.ancount = htons (1); // one answer RR
801 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 883 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
802 884
… …
824 if (SEQNO_EQ ((*i)->seqno, seqno)) 906 if (SEQNO_EQ ((*i)->seqno, seqno))
825 { 907 {
826 // already seen that request: simply reply with the cached reply 908 // already seen that request: simply reply with the cached reply
827 dns_rcv *r = *i; 909 dns_rcv *r = *i;
828 910
829 slog (L_DEBUG, "DUPLICATE %d\n", htons (r->pkt->id)); 911 slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
912
913 // refresh header & id, as the retry count could have changed
914 memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
915 r->pkt->id = pkt.id;
830 916
831 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 917 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
832 pkt.id = r->pkt->id; 918
833 goto duplicate_request; 919 goto duplicate_request;
834 } 920 }
835 921
836 // new packet, queue 922 // new packet, queue
837 rcv = new dns_rcv (seqno, data, datalen); 923 rcv = new dns_rcv (seqno, data, datalen);
838 dns->receive_rep (rcv); 924 dns->receive_rep (rcv);
839 } 925 }
840 926
927 {
841 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 928 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
842 929
843 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 930 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
844 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 931 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
845 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 932 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
846 pkt [offs++] = 0; pkt [offs++] = 0; 933 pkt [offs++] = 0; pkt [offs++] = 0;
847 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 934 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
848 935
849 int rdlen_offs = offs += 2; 936 int rdlen_offs = offs += 2;
850 937
938 if (dns)
939 {
851 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 940 int dlen = ntohs (dns->cfg.max_size) - offs;
941
852 // bind doesn't compress well, so reduce further by one label length 942 // bind doesn't compress well, so reduce further by one label length
853 dlen -= qlen; 943 dlen -= qlen;
854 944
855 if (dns) 945 // only put data into in-order sequence packets, if
856 { 946 // we receive out-of-order packets we generate empty
857 while (dlen > 1 && !dns->snddq.empty ()) 947 // replies
948 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
949 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
858 { 950 {
951 dns->repseq = seqno;
952
953 while (dlen > 1 && !dns->snddq.empty ())
954 {
859 int txtlen = dlen <= 255 ? dlen - 1 : 255; 955 int txtlen = dlen <= 255 ? dlen - 1 : 255;
860 956
861 if (txtlen > dns->snddq.size ()) 957 if (txtlen > dns->snddq.size ())
862 txtlen = dns->snddq.size (); 958 txtlen = dns->snddq.size ();
863 959
864 pkt[offs++] = txtlen; 960 pkt[offs++] = txtlen;
865 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 961 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
866 offs += txtlen; 962 offs += txtlen;
867 dns->snddq.remove (txtlen); 963 dns->snddq.remove (txtlen);
868 964
869 dlen -= txtlen + 1; 965 dlen -= txtlen + 1;
966 }
870 } 967 }
871 968
872 // avoid empty TXT rdata 969 // avoid completely empty TXT rdata
873 if (offs == rdlen_offs) 970 if (offs == rdlen_offs)
874 pkt[offs++] = 0; 971 pkt[offs++] = 0;
875 972
876 slog (L_NOISE, "snddq %d", dns->snddq.size ()); 973 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
877 } 974 }
878 else 975 else
879 { 976 {
880 // send RST 977 // send RST
881 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 978 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
882 pkt [offs++] = CMD_IP_RST; 979 pkt [offs++] = CMD_IP_RST;
883 } 980 }
884 981
885 int rdlen = offs - rdlen_offs; 982 int rdlen = offs - rdlen_offs;
886 983
887 pkt [rdlen_offs - 2] = rdlen >> 8; 984 pkt [rdlen_offs - 2] = rdlen >> 8;
888 pkt [rdlen_offs - 1] = rdlen; 985 pkt [rdlen_offs - 1] = rdlen;
889 986
890 if (dns) 987 if (dns)
891 { 988 {
892 // now update dns_rcv copy 989 // now update dns_rcv copy
893 rcv->pkt->len = offs; 990 rcv->pkt->len = offs;
894 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 991 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
895 } 992 }
993 }
896 994
897 duplicate_request: ; 995 duplicate_request: ;
898 } 996 }
899 else 997 else
900 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 998 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
912 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1010 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
913 pkt [offs++] = 0; pkt [offs++] = 0; 1011 pkt [offs++] = 0; pkt [offs++] = 0;
914 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1012 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
915 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1013 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
916 1014
917 slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client); 1015 slog (L_INFO, _("DNS: client %d connects"), client);
918 1016
919 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1017 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
920 pkt [offs++] = CMD_IP_REJ; 1018 pkt [offs++] = CMD_IP_REJ;
921 1019
922 if (0 < client && client <= conns.size ()) 1020 if (0 < client && client <= conns.size ())
… …
956 { 1054 {
957 dns_connection *dns = (*i)->dns; 1055 dns_connection *dns = (*i)->dns;
958 connection *c = dns->c; 1056 connection *c = dns->c;
959 int seqno = (*i)->seqno; 1057 int seqno = (*i)->seqno;
960 u8 data[MAXSIZE], *datap = data; 1058 u8 data[MAXSIZE], *datap = data;
1059 //printf ("rcv pkt %x\n", seqno);//D
961 1060
962 if ((*i)->retry) 1061 if ((*i)->retry)
963 { 1062 {
964 dns->send_interval *= 1.001; 1063 dns->send_interval *= 1.01;
965 if (dns->send_interval > MAX_SEND_INTERVAL) 1064 if (dns->send_interval > MAX_SEND_INTERVAL)
966 dns->send_interval = MAX_SEND_INTERVAL; 1065 dns->send_interval = MAX_SEND_INTERVAL;
967 } 1066 }
968 else 1067 else
969 { 1068 {
970#if 1 1069#if 0
971 dns->send_interval *= 0.9999; 1070 dns->send_interval *= 0.999;
972#endif 1071#endif
973 if (dns->send_interval < MIN_SEND_INTERVAL)
974 dns->send_interval = MIN_SEND_INTERVAL;
975
976 // the latency surely puts an upper bound on 1072 // the latency surely puts an upper bound on
977 // the minimum send interval 1073 // the minimum send interval
978 double latency = NOW - (*i)->sent; 1074 double latency = ev_now () - (*i)->sent;
979 1075
980 if (dns->send_interval > latency) 1076 if (latency < dns->min_latency)
981 dns->send_interval = latency; 1077 dns->min_latency = latency;
1078
1079 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1080 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1081
1082 if (dns->send_interval < conf.dns_send_interval)
1083 dns->send_interval = conf.dns_send_interval;
982 } 1084 }
983 1085
984 delete *i; 1086 delete *i;
985 dns_sndpq.erase (i); 1087 dns_sndpq.erase (i);
986 1088
… …
1036 1138
1037 if (ip [0] == CMD_IP_1 1139 if (ip [0] == CMD_IP_1
1038 && ip [1] == CMD_IP_2 1140 && ip [1] == CMD_IP_2
1039 && ip [2] == CMD_IP_3) 1141 && ip [2] == CMD_IP_3)
1040 { 1142 {
1041 slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]); 1143 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1042 1144
1043 if (ip [3] == CMD_IP_RST) 1145 if (ip [3] == CMD_IP_RST)
1044 { 1146 {
1045 slog (L_DEBUG, _("got tunnel RST request")); 1147 slog (L_DEBUG, _("DNS: got tunnel RST request"));
1046 1148
1047 delete dns; c->dns = 0; 1149 c->dnsv4_reset_connection ();
1048
1049 return;
1050 } 1150 }
1051 else if (ip [3] == CMD_IP_SYN) 1151 else if (ip [3] == CMD_IP_SYN)
1052 { 1152 {
1053 slog (L_DEBUG, _("got tunnel SYN reply, server likes us.")); 1153 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1054 dns->established = true; 1154 dns->established = true;
1055 } 1155 }
1056 else if (ip [3] == CMD_IP_REJ) 1156 else if (ip [3] == CMD_IP_REJ)
1057 {
1058 slog (L_DEBUG, _("got tunnel REJ reply, server does not like us, aborting.")); 1157 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1059 abort ();
1060 }
1061 else 1158 else
1062 slog (L_INFO, _("got unknown meta command %02x"), ip [3]); 1159 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1063 } 1160 }
1064 else 1161 else
1065 slog (L_INFO, _("got spurious a record %d.%d.%d.%d"), 1162 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1066 ip [0], ip [1], ip [2], ip [3]); 1163 ip [0], ip [1], ip [2], ip [3]);
1067 1164
1068 return; 1165 return;
1069 } 1166 }
1070 1167
1071 int client, rseqno; 1168 int client, rseqno;
1072 decode_header (qname, client, rseqno); 1169 decode_header (qname, client, rseqno);
1073 1170
1074 if (client != THISNODE->id) 1171 if (client != THISNODE->id)
1075 { 1172 {
1076 slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring")); 1173 slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1077 datap = 0; 1174 datap = 0;
1078 } 1175 }
1079 else if (rseqno != seqno) 1176 else if (rseqno != seqno)
1080 { 1177 {
1081 slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?")); 1178 slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
1082 datap = 0; 1179 datap = 0;
1083 } 1180 }
1084 } 1181 }
1085 } 1182 }
1086 1183
… …
1091 break; 1188 break;
1092 } 1189 }
1093} 1190}
1094 1191
1095void 1192void
1096vpn::dnsv4_ev (io_watcher &w, short revents) 1193vpn::dnsv4_ev (ev::io &w, int revents)
1097{ 1194{
1098 if (revents & EVENT_READ) 1195 if (revents & EV_READ)
1099 { 1196 {
1100 dns_packet *pkt = new dns_packet; 1197 dns_packet *pkt = new dns_packet;
1101 struct sockaddr_in sa; 1198 struct sockaddr_in sa;
1102 socklen_t sa_len = sizeof (sa); 1199 socklen_t sa_len = sizeof (sa);
1103 1200
1104 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1201 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1105 1202
1106 if (pkt->len > 0) 1203 if (pkt->len > 0)
1107 { 1204 {
1108 if (THISNODE->dns_port) 1205 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1206 dnsv4_client (*pkt);
1207 else
1109 { 1208 {
1110 dnsv4_server (*pkt); 1209 dnsv4_server (*pkt);
1111 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1210 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1112 } 1211 }
1113 else
1114 dnsv4_client (*pkt);
1115 1212
1116 delete pkt; 1213 delete pkt;
1117 } 1214 }
1118 } 1215 }
1119} 1216}
1120 1217
1121bool 1218bool
1122connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1219vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1123{ 1220{
1221 int client = ntohl (si.host);
1222
1223 assert (0 < client && client <= conns.size ());
1224
1225 connection *c = conns [client - 1];
1226
1124 if (!dns) 1227 if (!c->dns)
1125 dns = new dns_connection (this); 1228 c->dns = new dns_connection (c);
1126 1229
1127 if (!dns->snddq.put (pkt)) 1230 if (c->dns->snddq.put (pkt))
1128 return false; 1231 c->dns->tw ();
1129 1232
1130 dns->tw.trigger (); 1233 // always return true even if the buffer overflows
1131
1132 return true; 1234 return true;
1133} 1235}
1134 1236
1135void 1237void
1136connection::dnsv4_reset_connection () 1238connection::dnsv4_reset_connection ()
… …
1139} 1241}
1140 1242
1141#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1243#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1142 1244
1143void 1245void
1144dns_connection::time_cb (time_watcher &w) 1246dns_connection::time_cb (ev::timer &w, int revents)
1145{ 1247{
1146 // servers have to be polled 1248 // servers have to be polled
1147 if (THISNODE->dns_port) 1249 if (THISNODE->dns_port)
1148 return; 1250 return;
1149 1251
1150 // check for timeouts and (re)transmit 1252 // check for timeouts and (re)transmit
1151 tstamp next = NOW + poll_interval; 1253 tstamp next = ev::now () + poll_interval;
1152 dns_snd *send = 0; 1254 dns_snd *send = 0;
1153 1255
1154 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1256 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1155 i != vpn->dns_sndpq.end (); 1257 i != vpn->dns_sndpq.end ();
1156 ++i) 1258 ++i)
1157 { 1259 {
1158 dns_snd *r = *i; 1260 dns_snd *r = *i;
1159 1261
1160 if (r->timeout <= NOW) 1262 if (r->timeout <= ev_now ())
1161 { 1263 {
1162 if (!send) 1264 if (!send)
1163 { 1265 {
1164 send = r; 1266 send = r;
1165 1267
1166 r->retry++; 1268 r->retry++;
1167 r->timeout = NOW + r->retry; 1269 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1270 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1271
1272 // the following code changes the query section a bit, forcing
1273 // the forwarder to generate a new request
1274 if (r->stdhdr)
1275 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1168 } 1276 }
1169 } 1277 }
1170 else 1278 else
1171 NEXT (r->timeout); 1279 NEXT (r->timeout);
1172 } 1280 }
1173 1281
1174 if (last_sent + send_interval <= NOW)
1175 {
1176 if (!send) 1282 if (!send)
1283 {
1284 // generate a new packet, if wise
1285
1286 if (!established)
1177 { 1287 {
1178 // generate a new packet, if wise
1179
1180 if (!established)
1181 {
1182 if (vpn->dns_sndpq.empty ()) 1288 if (vpn->dns_sndpq.empty ())
1183 {
1184 send = new dns_snd (this);
1185
1186 cfg.reset (THISNODE->id);
1187 send->gen_syn_req (cfg);
1188 }
1189 }
1190 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
1191 { 1289 {
1192 send = new dns_snd (this); 1290 send = new dns_snd (this);
1291
1292 cfg.reset (THISNODE->id);
1293 send->gen_syn_req ();
1294 }
1295 }
1296 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1297 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1298 {
1299 if (last_sent + send_interval <= ev_now ())
1300 {
1301 //printf ("sending data request etc.\n"); //D
1302 if (!snddq.empty () || last_received + 1. > ev_now ())
1303 {
1304 poll_interval = send_interval;
1305 NEXT (ev_now () + send_interval);
1306 }
1307
1308 send = new dns_snd (this);
1193 send->gen_stream_req (sndseq, snddq); 1309 send->gen_stream_req (sndseq, snddq);
1310 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1311 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1194 1312
1195 sndseq = (sndseq + 1) & SEQNO_MASK; 1313 sndseq = (sndseq + 1) & SEQNO_MASK;
1196 } 1314 }
1197 1315 else
1198 if (send) 1316 NEXT (last_sent + send_interval);
1199 vpn->dns_sndpq.push_back (send);
1200 } 1317 }
1201 1318
1202 if (send) 1319 if (send)
1203 { 1320 vpn->dns_sndpq.push_back (send);
1204 last_sent = NOW; 1321 }
1322
1323 if (send)
1324 {
1325 last_sent = ev_now ();
1205 sendto (vpn->dnsv4_fd, 1326 sendto (vpn->dnsv4_fd,
1206 send->pkt->at (0), send->pkt->len, 0, 1327 send->pkt->at (0), send->pkt->len, 0,
1207 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1328 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1208 }
1209 } 1329 }
1210 else
1211 NEXT (last_sent + send_interval);
1212 1330
1213 slog (L_NOISE, "pi %f si %f N %f (%d:%d)", 1331 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1214 poll_interval, send_interval, next - NOW, 1332 poll_interval, send_interval, next - ev_now (),
1215 vpn->dns_sndpq.size (), snddq.size ()); 1333 vpn->dns_sndpq.size (), snddq.size (),
1334 rcvpq.size ());
1216 1335
1217 // TODO: no idea when this happens, but when next < NOW, we have a problem 1336 // TODO: no idea when this happens, but when next < ev_now (), we have a problem
1337 // doesn't seem to happen anymore
1218 if (next < NOW + 0.0001) 1338 if (next < ev_now () + 0.001)
1219 next = NOW + 0.1; 1339 next = ev_now () + 0.1;
1220 1340
1221 w.start (next); 1341 w.start (next - ev_now ());
1222} 1342}
1223 1343
1224#endif 1344#endif
1225 1345

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