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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.35 by pcg, Wed Mar 16 14:56:32 2005 UTC vs.
Revision 1.54 by root, Tue Oct 18 11:07:28 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. 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
38#include <unistd.h> 52#include <unistd.h>
39#include <fcntl.h> 53#include <fcntl.h>
40 54
41#include <map> 55#include <map>
42 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
43#include <gmp.h> 58#include <gmp.h>
44 59
45#include "netcompat.h" 60#include "netcompat.h"
46 61
47#include "vpn.h" 62#include "vpn.h"
48 63
64#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received
49#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
50#define ACTIVITY_INTERVAL 5.
51
52#define TIMEOUT_FACTOR 2.
53 66
54#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
55#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
56 69
57#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
58#define MAX_SEND_INTERVAL 2. // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
59 71
60#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
61#define MAX_OUTSTANDING 100 // max. outstanding requests
62#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
63#define MAX_BACKLOG (64*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
64 74
65#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well 75#define MAX_DOMAIN_SIZE 235 // 255 is legal limit, but bind doesn't compress well
66// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
67// every request byte less give room for two reply bytes 77// every request byte less give room for two reply bytes
68 78
69#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
70#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
73#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
74 84
75#define RR_TYPE_A 1 85#define RR_TYPE_A 1
76#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
77#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
78#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
79 90
80#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
81 92
82#define CMD_IP_1 207 93#define CMD_IP_1 207
83#define CMD_IP_2 46 94#define CMD_IP_2 46
84#define CMD_IP_3 236 95#define CMD_IP_3 236
85#define CMD_IP_RST 29 96
86#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
87#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}
88 113
89// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
90struct charmap 115struct charmap
91{ 116{
92 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
106 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
107 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
108 133
109 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
110 { 135 {
136 char c = cmap [size];
137
111 enc [size] = cmap [size]; 138 enc [size] = c;
112 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;
113 } 144 }
114 145
115 assert (size < 256); 146 assert (size < 256);
116} 147}
117 148
124{ 155{
125 charmap cmap; 156 charmap cmap;
126 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
127 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
128 159
129 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
130 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
131 162
132 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
133 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
134 165
135 basecoder (const char *cmap); 166 basecoder (const char *cmap);
136}; 167};
137 168
138basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
157 enc_len [len] = n; 188 enc_len [len] = n;
158 dec_len [n] = len; 189 dec_len [n] = len;
159 } 190 }
160} 191}
161 192
193unsigned int
162unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
163{ 195{
164 return enc_len [len]; 196 return enc_len [len];
165} 197}
166 198
199unsigned int
167unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
168{ 201{
169 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
170 --len; 203 --len;
171 204
172 return dec_len [len]; 205 return dec_len [len];
173} 206}
174 207
208unsigned int
175unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
176{ 210{
177 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
178 return 0; 212 return 0;
179 213
180 int elen = encode_len (len); 214 int elen = encode_len (len);
199 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
200 234
201 return elen; 235 return elen;
202} 236}
203 237
238unsigned int
204unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
205{ 240{
206 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
207 return 0; 242 return 0;
208 243
209 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
258 } 293 }
259 abort (); 294 abort ();
260} 295}
261#endif 296#endif
262 297
263//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
264//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
265static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
266//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
267static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
268 301
269///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
270 303
271#define HDRSIZE 6 304#define HDRSIZE 5
272 305
306inline void
273inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
274{ 308{
309 assert (clientid < 256);
310
275 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
276 312
277 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
278 clientid, 316 clientid,
279 (seqno >> 8) | (retry << 6),
280 seqno,
281 }; 317 };
282 318
283 assert (clientid < 256);
284
285 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
286} 320}
287 321
322inline void
288inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
289{ 324{
290 u8 hdr[3]; 325 u8 hdr[3];
291 326
292 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
293 328
294 clientid = hdr[0]; 329 clientid = hdr[2];
295 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
296} 331}
297 332
298///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
299 334
300struct byte_stream 335struct byte_stream
326byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
327{ 362{
328 delete data; 363 delete data;
329} 364}
330 365
366void
331void byte_stream::remove (int count) 367byte_stream::remove (int count)
332{ 368{
333 if (count > fill) 369 if (count > fill)
334 assert (count <= fill); 370 assert (count <= fill);
335 371
336 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
337} 373}
338 374
375bool
339bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
340{ 377{
341 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
342 return false; 379 return false;
343 380
344 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
345 382
346 return true; 383 return true;
347} 384}
348 385
386bool
349bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
350{ 388{
351 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
352 return false; 390 return false;
353 391
354 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
359 return true; 397 return true;
360} 398}
361 399
362vpn_packet *byte_stream::get () 400vpn_packet *byte_stream::get ()
363{ 401{
402 if (fill < 2)
403 return 0;
404
364 unsigned int len; 405 unsigned int len;
365 406
366 for (;;) 407 for (;;)
367 { 408 {
368 len = (data [0] << 8) | data [1]; 409 len = (data [0] << 8) | data [1];
369 410
370 if (len <= MAXSIZE || fill < 2) 411 if (len <= MAXSIZE)
371 break; 412 break;
372 413
373 // TODO: handle this better than skipping, e.g. by reset 414 // TODO: handle this better than skipping, e.g. by reset
374 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte...")); 415 slog (L_DEBUG, _("DNS: corrupted packet (%02x %02x) stream skipping a byte..."), data [0], data [1]);
375 remove (1); 416 remove (1);
376 } 417 }
377 418
378 if (fill < len + 2) 419 if (fill < len + 2)
379 return 0; 420 return 0;
410 451
411struct dns_cfg 452struct dns_cfg
412{ 453{
413 static int next_uid; 454 static int next_uid;
414 455
415 u8 id1, id2, id3, id4; 456 u8 chksum;
457 u8 rrtype;
458 u16 uid; // to make request unique
416 459
417 u8 version; 460 u8 version;
418 u8 flags; 461 u8 flags;
419 u8 rrtype; 462 u16 max_size;
463
464 u8 id1, id2, id3, id4;
465
466 u16 client;
420 u8 def_ttl; 467 u8 def_ttl;
468 u8 r0;
421 469
422 u16 client; 470 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
423 u16 uid; // to make request unique 471 u8 hdr_cdc; // cdc en/decoder for regular request headers
472 u8 req_cdc; // cdc en/decoder for regular (ANY?) request data
473 u8 rep_cdc; // cdc en/decoder for regular (TXT) replies, 0 == 8 bit encoding
424 474
425 u16 max_size;
426 u8 seq_cdc;
427 u8 req_cdc;
428
429 u8 rep_cdc;
430 u8 delay; // time in 0.01s units that the server may delay replying packets
431 u8 r3, r4;
432
433 u8 r5, r6, r7, r8; 475 u8 r1, r2, r3, r4;
434 476
435 void reset (int clientid); 477 void reset (int clientid);
436 bool valid (); 478 bool valid ();
479 u8 get_chksum ();
437}; 480};
438 481
439int dns_cfg::next_uid; 482int dns_cfg::next_uid;
440 483
484void
441void dns_cfg::reset (int clientid) 485dns_cfg::reset (int clientid)
442{ 486{
487 // this ID must result in some mixed-case characters in cdc26-encoding
443 id1 = 'G'; 488 id1 = 'G';
444 id2 = 'V'; 489 id2 = 'V';
445 id3 = 'P'; 490 id3 = 'P';
446 id4 = 'E'; 491 id4 = 'E';
447 492
448 version = 1; 493 version = 2;
449 494
450 rrtype = RR_TYPE_TXT; 495 rrtype = RR_TYPE_TXT;
451 flags = 0; 496 flags = 0;
452 def_ttl = 0; 497 def_ttl = 0;
453 seq_cdc = 26; 498 syn_cdc = 26;
454 req_cdc = 62; 499 hdr_cdc = 36;
500 req_cdc = conf.dns_case_preserving ? 62 : 36;
455 rep_cdc = 0; 501 rep_cdc = 0;
456 max_size = htons (MAX_PKT_SIZE); 502 max_size = htons (MAX_PKT_SIZE);
457 client = htons (clientid); 503 client = htons (clientid);
458 uid = next_uid++; 504 uid = ++next_uid;
459 delay = 0;
460 505
461 r3 = r4 = 0; 506 r0 = r1 = r2 = r3 = r4 = 0;
462 r4 = r5 = r6 = r7 = 0;
463}
464 507
508 chksum = get_chksum ();
509}
510
511// simple but not trivial chksum
512u8
513dns_cfg::get_chksum ()
514{
515 unsigned int sum = 0xff00; // only 16 bits required
516
517 u8 old_chksum = chksum;
518 chksum = 0;
519
520 for (unsigned int i = 0; i < sizeof (*this); ++i)
521 sum += ((u8 *)this)[i] * (i + 1);
522
523 chksum = old_chksum;
524
525 return sum + (sum >> 8);
526}
527
528bool
465bool dns_cfg::valid () 529dns_cfg::valid ()
466{ 530{
531 // although the protocol itself allows for some configurability,
532 // only the following encoding/decoding settings are implemented.
467 return id1 == 'G' 533 return id1 == 'G'
468 && id2 == 'V' 534 && id2 == 'V'
469 && id3 == 'P' 535 && id3 == 'P'
470 && id4 == 'E' 536 && id4 == 'E'
537 && version == 2
471 && seq_cdc == 26 538 && syn_cdc == 26
472 && req_cdc == 62 539 && hdr_cdc == 36
540 && (req_cdc == 36 || req_cdc == 62)
473 && rep_cdc == 0 541 && rep_cdc == 0
474 && version == 1; 542 && chksum == get_chksum ();
475} 543}
476 544
477struct dns_packet : net_packet 545struct dns_packet : net_packet
478{ 546{
479 u16 id; 547 u16 id;
483 u8 data [MAXSIZE - 6 * 2]; 551 u8 data [MAXSIZE - 6 * 2];
484 552
485 int decode_label (char *data, int size, int &offs); 553 int decode_label (char *data, int size, int &offs);
486}; 554};
487 555
556int
488int dns_packet::decode_label (char *data, int size, int &offs) 557dns_packet::decode_label (char *data, int size, int &offs)
489{ 558{
490 char *orig = data; 559 char *orig = data;
491 560
492 memset (data, 0, size); 561 memset (data, 0, size);
493 562
519 return data - orig; 588 return data - orig;
520} 589}
521 590
522///////////////////////////////////////////////////////////////////////////// 591/////////////////////////////////////////////////////////////////////////////
523 592
593static
594u16 next_id ()
595{
524static u16 dns_id = 0; // TODO: should be per-vpn 596 static u16 dns_id = 0; // TODO: should be per-vpn
525 597
526static u16 next_id () 598#if 1
527{
528 if (!dns_id) 599 if (!dns_id)
529 dns_id = time (0); 600 dns_id = time (0);
530 601
531 // the simplest lsfr with periodicity 65535 i could find 602 // the simplest lsfr with periodicity 65535 i could find
532 dns_id = (dns_id << 1) 603 dns_id = (dns_id << 1)
534 ^ (dns_id >> 2) 605 ^ (dns_id >> 2)
535 ^ (dns_id >> 4) 606 ^ (dns_id >> 4)
536 ^ (dns_id >> 15)) & 1); 607 ^ (dns_id >> 15)) & 1);
537 608
538 return dns_id; 609 return dns_id;
610#else
611 dns_id++;//D
612
613 return htons (dns_id);
614#endif
539} 615}
540 616
541struct dns_rcv; 617struct dns_rcv;
542struct dns_snd; 618struct dns_snd;
543 619
547 struct vpn *vpn; 623 struct vpn *vpn;
548 624
549 dns_cfg cfg; 625 dns_cfg cfg;
550 626
551 bool established; 627 bool established;
628 const basecoder *cdc;
552 629
553 tstamp last_received; 630 tstamp last_received;
554 tstamp last_sent; 631 tstamp last_sent;
555 double min_latency; 632 double min_latency;
556 double poll_interval, send_interval; 633 double poll_interval, send_interval;
558 vector<dns_rcv *> rcvpq; 635 vector<dns_rcv *> rcvpq;
559 636
560 byte_stream rcvdq; int rcvseq; int repseq; 637 byte_stream rcvdq; int rcvseq; int repseq;
561 byte_stream snddq; int sndseq; 638 byte_stream snddq; int sndseq;
562 639
563 void time_cb (time_watcher &w); time_watcher tw; 640 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
564 void receive_rep (dns_rcv *r); 641 void receive_rep (dns_rcv *r);
642
643 void reset (); // quite like tcp RST
644 void set_cfg (); // to be called after any cfg changes
565 645
566 dns_connection (connection *c); 646 dns_connection (connection *c);
567 ~dns_connection (); 647 ~dns_connection ();
568}; 648};
569 649
587: dns (dns) 667: dns (dns)
588{ 668{
589 timeout = 0; 669 timeout = 0;
590 retry = 0; 670 retry = 0;
591 seqno = 0; 671 seqno = 0;
592 sent = NOW; 672 sent = ev_now ();
593 stdhdr = false; 673 stdhdr = false;
594 674
595 pkt = new dns_packet; 675 pkt = new dns_packet;
596 676
597 pkt->id = next_id (); 677 pkt->id = next_id ();
600dns_snd::~dns_snd () 680dns_snd::~dns_snd ()
601{ 681{
602 delete pkt; 682 delete pkt;
603} 683}
604 684
685static void
605static void append_domain (dns_packet &pkt, int &offs, const char *domain) 686append_domain (dns_packet &pkt, int &offs, const char *domain)
606{ 687{
607 // add tunnel domain 688 // add tunnel domain
608 for (;;) 689 for (;;)
609 { 690 {
610 const char *end = strchr (domain, '.'); 691 const char *end = strchr (domain, '.');
623 704
624 domain = end + 1; 705 domain = end + 1;
625 } 706 }
626} 707}
627 708
709void
628void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 710dns_snd::gen_stream_req (int seqno, byte_stream &stream)
629{ 711{
630 stdhdr = true; 712 stdhdr = true;
631 this->seqno = seqno; 713 this->seqno = seqno;
632 714
633 timeout = NOW + INITIAL_TIMEOUT; 715 timeout = ev_now () + INITIAL_TIMEOUT;
634 716
635 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 717 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
636 pkt->qdcount = htons (1); 718 pkt->qdcount = htons (1);
637 719
638 int offs = 6*2; 720 int offs = 6*2;
641 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 723 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
642 724
643 char enc[256], *encp = enc; 725 char enc[256], *encp = enc;
644 encode_header (enc, THISNODE->id, seqno); 726 encode_header (enc, THISNODE->id, seqno);
645 727
646 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 728 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
647 729
648 if (datalen > stream.size ()) 730 if (datalen > stream.size ())
649 datalen = stream.size (); 731 datalen = stream.size ();
650 732
651 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 733 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
652 stream.remove (datalen); 734 stream.remove (datalen);
653 735
654 while (enclen) 736 while (enclen)
655 { 737 {
656 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 738 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
671 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 753 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
672 754
673 pkt->len = offs; 755 pkt->len = offs;
674} 756}
675 757
758void
676void dns_snd::gen_syn_req () 759dns_snd::gen_syn_req ()
677{ 760{
678 timeout = NOW + INITIAL_SYN_TIMEOUT; 761 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
679 762
680 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 763 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
681 pkt->qdcount = htons (1); 764 pkt->qdcount = htons (1);
682 765
683 int offs = 6 * 2; 766 int offs = 6 * 2;
723 806
724dns_connection::dns_connection (connection *c) 807dns_connection::dns_connection (connection *c)
725: c (c) 808: c (c)
726, rcvdq (MAX_BACKLOG * 2) 809, rcvdq (MAX_BACKLOG * 2)
727, snddq (MAX_BACKLOG) 810, snddq (MAX_BACKLOG)
728, tw (this, &dns_connection::time_cb)
729{ 811{
812 tw.set<dns_connection, &dns_connection::time_cb> (this);
813
730 vpn = c->vpn; 814 vpn = c->vpn;
731 815
816 reset ();
817}
818
819dns_connection::~dns_connection ()
820{
821 reset ();
822}
823
824void
825dns_connection::reset ()
826{
827 while (!rcvpq.empty ())
828 {
829 delete rcvpq.back ();
830 rcvpq.pop_back ();
831 }
832
833 for (int i = vpn->dns_sndpq.size (); i--; )
834 if (vpn->dns_sndpq [i]->dns == this)
835 {
836 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
837 vpn->dns_sndpq.pop_back ();
838 }
839
732 established = false; 840 established = false;
733 841
734 rcvseq = repseq = sndseq = 0; 842 rcvseq = repseq = sndseq = 0;
735 843
736 last_sent = last_received = 0; 844 last_sent = 0;
737 poll_interval = 0.5; // starting here 845 poll_interval = 0.5; // starting here
738 send_interval = 0.5; // starting rate 846 send_interval = 0.5; // starting rate
739 min_latency = INITIAL_TIMEOUT; 847 min_latency = INITIAL_TIMEOUT;
740} 848}
741 849
742dns_connection::~dns_connection () 850void
851dns_connection::set_cfg ()
743{ 852{
744 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 853 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
745 i != rcvpq.end ();
746 ++i)
747 delete *i;
748} 854}
749 855
856void
750void dns_connection::receive_rep (dns_rcv *r) 857dns_connection::receive_rep (dns_rcv *r)
751{ 858{
752 if (r->datalen) 859 if (r->datalen)
753 { 860 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
754 last_received = NOW;
755 tw.trigger ();
756
757 poll_interval = send_interval;
758 }
759 else 861 else
760 { 862 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
761 poll_interval *= 1.5;
762
763 if (poll_interval > MAX_POLL_INTERVAL)
764 poll_interval = MAX_POLL_INTERVAL;
765 }
766 863
767 rcvpq.push_back (r); 864 rcvpq.push_back (r);
768 865
769 redo: 866 redo:
770 867
771 // find next packet 868 // find next packet
772 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 869 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
773 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 870 if (SEQNO_EQ (rcvseq, (*i)->seqno))
774 { 871 {
872 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
775 // enter the packet into our input stream 873 // enter the packet into our input stream
776 r = *i; 874 r = *i;
777 875
778 // remove the oldest packet, look forward, as it's oldest first 876 // remove the oldest packet, look forward, as it's oldest first
779 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 877 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
780 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 878 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
781 { 879 {
880 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
782 delete *j; 881 delete *j;
783 rcvpq.erase (j); 882 rcvpq.erase (j);
784 break; 883 break;
785 } 884 }
786 885
787 rcvseq = (rcvseq + 1) & SEQNO_MASK; 886 rcvseq = (rcvseq + 1) & SEQNO_MASK;
788 887
789 if (!rcvdq.put (r->data, r->datalen)) 888 if (!rcvdq.put (r->data, r->datalen))
790 { 889 {
890 // MUST never overflow, can be caused by data corruption, TODO
791 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 891 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
792 abort (); // MUST never overflow, can be caused by data corruption, TODO 892 reset ();
893 return;
793 } 894 }
794 895
795 while (vpn_packet *pkt = rcvdq.get ()) 896 while (vpn_packet *pkt = rcvdq.get ())
796 { 897 {
797 sockinfo si; 898 sockinfo si;
798 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; 899 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
799 900
800 vpn->recv_vpn_packet (pkt, si); 901 vpn->recv_vpn_packet (pkt, si);
801
802 delete pkt; 902 delete pkt;
803 } 903 }
804 904
805 // check for further packets 905 // check for further packets
806 goto redo; 906 goto redo;
849 { 949 {
850 // correct class, domain: parse 950 // correct class, domain: parse
851 int client, seqno; 951 int client, seqno;
852 decode_header (qname, client, seqno); 952 decode_header (qname, client, seqno);
853 953
854 u8 data[MAXSIZE];
855 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
856
857 if (0 < client && client <= conns.size ()) 954 if (0 < client && client <= conns.size ())
858 { 955 {
859 connection *c = conns [client - 1]; 956 connection *c = conns [client - 1];
860 dns_connection *dns = c->dns; 957 dns_connection *dns = c->dns;
861 dns_rcv *rcv; 958 dns_rcv *rcv;
862 959
863 if (dns) 960 if (dns)
864 { 961 {
962 u8 data[MAXSIZE];
963 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
964
865 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 965 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
866 if (SEQNO_EQ ((*i)->seqno, seqno)) 966 if (SEQNO_EQ ((*i)->seqno, seqno))
867 { 967 {
868 // already seen that request: simply reply with the cached reply 968 // already seen that request: simply reply with the cached reply
869 dns_rcv *r = *i; 969 dns_rcv *r = *i;
970 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1070 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
971 pkt [offs++] = 0; pkt [offs++] = 0; 1071 pkt [offs++] = 0; pkt [offs++] = 0;
972 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1072 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
973 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1073 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
974 1074
975 slog (L_INFO, _("DNS: client %d connects"), client);
976
977 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1075 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
978 pkt [offs++] = CMD_IP_REJ; 1076 pkt [offs++] = CMD_IP_REJ;
979 1077
980 if (0 < client && client <= conns.size ()) 1078 if (0 < client && client <= conns.size ())
981 { 1079 {
982 connection *c = conns [client - 1]; 1080 connection *c = conns [client - 1];
983 1081
984 if (cfg.valid ()) 1082 if (cfg.valid ())
985 { 1083 {
986 pkt [offs - 1] = CMD_IP_SYN; 1084 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1085
1086 // check for any encoding mismatches - hints at a case problem
1087 char qname2 [MAX_ENC_LEN];
1088 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
987 1089
988 delete c->dns; 1090 delete c->dns;
1091
1092 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1093 ? CMD_IP_CSE : CMD_IP_SYN;
1094
989 c->dns = new dns_connection (c); 1095 c->dns = new dns_connection (c);
990 c->dns->cfg = cfg; 1096 c->dns->cfg = cfg;
1097 c->dns->set_cfg ();
991 } 1098 }
992 } 1099 }
993 } 1100 }
994 } 1101 }
995 1102
1014 { 1121 {
1015 dns_connection *dns = (*i)->dns; 1122 dns_connection *dns = (*i)->dns;
1016 connection *c = dns->c; 1123 connection *c = dns->c;
1017 int seqno = (*i)->seqno; 1124 int seqno = (*i)->seqno;
1018 u8 data[MAXSIZE], *datap = data; 1125 u8 data[MAXSIZE], *datap = data;
1126 //printf ("rcv pkt %x\n", seqno);//D
1019 1127
1020 if ((*i)->retry) 1128 if ((*i)->retry)
1021 { 1129 {
1022 dns->send_interval *= 1.01; 1130 dns->send_interval *= 1.01;
1023 if (dns->send_interval > MAX_SEND_INTERVAL) 1131 if (dns->send_interval > MAX_SEND_INTERVAL)
1028#if 0 1136#if 0
1029 dns->send_interval *= 0.999; 1137 dns->send_interval *= 0.999;
1030#endif 1138#endif
1031 // the latency surely puts an upper bound on 1139 // the latency surely puts an upper bound on
1032 // the minimum send interval 1140 // the minimum send interval
1033 double latency = NOW - (*i)->sent; 1141 double latency = ev_now () - (*i)->sent;
1034 1142
1035 if (latency < dns->min_latency) 1143 if (latency < dns->min_latency)
1036 dns->min_latency = latency; 1144 dns->min_latency = latency;
1037 1145
1038 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR) 1146 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1039 dns->send_interval = dns->min_latency * LATENCY_FACTOR; 1147 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1040 1148
1041 if (dns->send_interval < MIN_SEND_INTERVAL) 1149 if (dns->send_interval < conf.dns_send_interval)
1042 dns->send_interval = MIN_SEND_INTERVAL; 1150 dns->send_interval = conf.dns_send_interval;
1043 } 1151 }
1044 1152
1045 delete *i; 1153 delete *i;
1046 dns_sndpq.erase (i); 1154 dns_sndpq.erase (i);
1047 1155
1065 ttl |= pkt [offs++] << 16; 1173 ttl |= pkt [offs++] << 16;
1066 ttl |= pkt [offs++] << 8; 1174 ttl |= pkt [offs++] << 8;
1067 ttl |= pkt [offs++]; 1175 ttl |= pkt [offs++];
1068 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1176 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1069 1177
1070 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1178 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1071 { 1179 {
1072 if (rdlen <= MAXSIZE - offs) 1180 if (rdlen <= MAXSIZE - offs)
1073 { 1181 {
1074 // decode bytes, finally 1182 // decode bytes, finally
1075 1183
1101 { 1209 {
1102 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1210 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1103 1211
1104 if (ip [3] == CMD_IP_RST) 1212 if (ip [3] == CMD_IP_RST)
1105 { 1213 {
1106 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1214 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1107 1215
1108 delete dns; c->dns = 0; 1216 dns->reset ();
1109
1110 return; 1217 return;
1111 } 1218 }
1112 else if (ip [3] == CMD_IP_SYN) 1219 else if (ip [3] == CMD_IP_SYN)
1113 { 1220 {
1114 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1221 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1115 dns->established = true; 1222 dns->established = true;
1116 } 1223 }
1224 else if (ip [3] == CMD_IP_CSE)
1225 {
1226 if (conf.dns_case_preserving)
1227 {
1228 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1229 conf.dns_case_preserving = false;
1230 dns->reset ();
1231 return;
1232 }
1233 else
1234 {
1235 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1236 dns->established = true;
1237 }
1238 }
1117 else if (ip [3] == CMD_IP_REJ) 1239 else if (ip [3] == CMD_IP_REJ)
1118 { 1240 {
1119 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1241 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1120 abort (); 1242 dns->tw.start (60.);
1121 } 1243 }
1122 else 1244 else
1245 {
1123 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1246 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1247 dns->tw.start (60.);
1248 }
1124 } 1249 }
1125 else 1250 else
1126 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1251 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1127 ip [0], ip [1], ip [2], ip [3]); 1252 ip [0], ip [1], ip [2], ip [3]);
1128 1253
1152 break; 1277 break;
1153 } 1278 }
1154} 1279}
1155 1280
1156void 1281void
1157vpn::dnsv4_ev (io_watcher &w, short revents) 1282vpn::dnsv4_ev (ev::io &w, int revents)
1158{ 1283{
1159 if (revents & EVENT_READ) 1284 if (revents & EV_READ)
1160 { 1285 {
1161 dns_packet *pkt = new dns_packet; 1286 dns_packet *pkt = new dns_packet;
1162 struct sockaddr_in sa; 1287 struct sockaddr_in sa;
1163 socklen_t sa_len = sizeof (sa); 1288 socklen_t sa_len = sizeof (sa);
1164 1289
1190 1315
1191 if (!c->dns) 1316 if (!c->dns)
1192 c->dns = new dns_connection (c); 1317 c->dns = new dns_connection (c);
1193 1318
1194 if (c->dns->snddq.put (pkt)) 1319 if (c->dns->snddq.put (pkt))
1320 {
1321 min_it (c->dns->poll_interval, 0.25);
1195 c->dns->tw.trigger (); 1322 c->dns->tw ();
1323 }
1196 1324
1197 // always return true even if the buffer overflows 1325 // always return true even if the buffer overflows
1198 return true; 1326 return true;
1199} 1327}
1200 1328
1201void 1329void
1202connection::dnsv4_reset_connection () 1330dns_connection::time_cb (ev::timer &w, int revents)
1203{
1204 //delete dns; dns = 0; //TODO
1205}
1206
1207#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1208
1209void
1210dns_connection::time_cb (time_watcher &w)
1211{ 1331{
1212 // servers have to be polled 1332 // servers have to be polled
1213 if (THISNODE->dns_port) 1333 if (THISNODE->dns_port)
1214 return; 1334 return;
1215 1335
1216 // check for timeouts and (re)transmit 1336 // check for timeouts and (re)transmit
1217 tstamp next = NOW + poll_interval; 1337 tstamp next = 86400 * 365;
1218 dns_snd *send = 0; 1338 dns_snd *send = 0;
1219 1339
1220 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1340 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1221 i != vpn->dns_sndpq.end (); 1341 i != vpn->dns_sndpq.end ();
1222 ++i) 1342 ++i)
1223 { 1343 {
1224 dns_snd *r = *i; 1344 dns_snd *r = *i;
1225 1345
1226 if (r->timeout <= NOW) 1346 if (r->timeout <= ev_now ())
1227 { 1347 {
1228 if (!send) 1348 if (!send)
1229 { 1349 {
1230 send = r; 1350 send = r;
1231 1351
1232 r->retry++; 1352 r->retry++;
1233 r->timeout = NOW + (r->retry * min_latency * TIMEOUT_FACTOR); 1353 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1354 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1234 1355
1235 // the following code changes the query section a bit, forcing 1356 // the following code changes the query section a bit, forcing
1236 // the forwarder to generate a new request 1357 // the forwarder to generate a new request
1237 if (r->stdhdr) 1358 if (r->stdhdr)
1238 {
1239 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1240 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1359 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1241 }
1242 } 1360 }
1243 } 1361 }
1244 else 1362 else
1245 NEXT (r->timeout); 1363 min_it (next, r->timeout - ev_now ());
1246 } 1364 }
1247 1365
1248 if (!send) 1366 if (!send)
1249 { 1367 {
1250 // generate a new packet, if wise 1368 // generate a new packet, if wise
1254 if (vpn->dns_sndpq.empty ()) 1372 if (vpn->dns_sndpq.empty ())
1255 { 1373 {
1256 send = new dns_snd (this); 1374 send = new dns_snd (this);
1257 1375
1258 cfg.reset (THISNODE->id); 1376 cfg.reset (THISNODE->id);
1377 set_cfg ();
1259 send->gen_syn_req (); 1378 send->gen_syn_req ();
1260 } 1379 }
1261 } 1380 }
1262 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1381 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1263 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1382 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1264 { 1383 {
1265 if (last_sent + send_interval <= NOW) 1384 if (last_sent + send_interval <= ev_now ())
1266 { 1385 {
1267 //printf ("sending data request etc.\n"); //D 1386 //printf ("sending data request etc.\n"); //D
1268 if (!snddq.empty () || last_received + 1. > NOW) 1387 if (!snddq.empty ())
1269 {
1270 poll_interval = send_interval;
1271 NEXT (NOW + send_interval); 1388 min_it (next, send_interval);
1272 }
1273 1389
1274 send = new dns_snd (this); 1390 send = new dns_snd (this);
1275 send->gen_stream_req (sndseq, snddq); 1391 send->gen_stream_req (sndseq, snddq);
1276 send->timeout = NOW + min_latency * TIMEOUT_FACTOR; 1392 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1393 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1277 1394
1278 sndseq = (sndseq + 1) & SEQNO_MASK; 1395 sndseq = (sndseq + 1) & SEQNO_MASK;
1279 } 1396 }
1280 else 1397 else
1281 NEXT (last_sent + send_interval); 1398 min_it (next, last_sent + send_interval - ev_now ());
1282 } 1399 }
1283 1400
1284 if (send) 1401 if (send)
1285 vpn->dns_sndpq.push_back (send); 1402 vpn->dns_sndpq.push_back (send);
1286 } 1403 }
1287 1404
1288 if (send) 1405 if (send)
1289 { 1406 {
1290 last_sent = NOW; 1407 last_sent = ev_now ();
1291 sendto (vpn->dnsv4_fd, 1408 sendto (vpn->dnsv4_fd,
1292 send->pkt->at (0), send->pkt->len, 0, 1409 send->pkt->at (0), send->pkt->len, 0,
1293 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1410 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1294 } 1411 }
1295 1412
1413 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1414
1296 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1415 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1297 poll_interval, send_interval, next - NOW, 1416 poll_interval, send_interval, next - ev_now (),
1298 vpn->dns_sndpq.size (), snddq.size (), 1417 vpn->dns_sndpq.size (), snddq.size (),
1299 rcvpq.size ()); 1418 rcvpq.size ());
1300 1419
1301 // TODO: no idea when this happens, but when next < NOW, we have a problem
1302 if (next < NOW + 0.001)
1303 next = NOW + 0.1;
1304
1305 w.start (next); 1420 w.start (next);
1306} 1421}
1307 1422
1308#endif 1423#endif
1309 1424

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