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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC vs.
Revision 1.53 by root, Tue Oct 18 10:54:17 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
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 .2 // how often to poll minimally when the server is having data 64#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received
49#define MAX_POLL_INTERVAL 6. // 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 66
52#define INITIAL_TIMEOUT 1. 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
53#define INITIAL_SYN_TIMEOUT 2. 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54 69
55#define MIN_SEND_INTERVAL (1./1000.)
56#define MAX_SEND_INTERVAL 0.5 // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
57 71
58#define MAX_OUTSTANDING 400 // max. outstanding requests
59#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
60#define MAX_RATE 100 // requests/s
61#define MAX_BACKLOG (100*1024) // size of protocol backlog, must be > MAXSIZE 73#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
62 74
63#define MAX_DOMAIN_SIZE 220 // 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
64// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
65// every two request byte sless give room for one reply byte 77// every request byte less give room for two reply bytes
66 78
67#define SEQNO_MASK 0xffff 79#define SEQNO_MASK 0x3fff
68#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
69 81
70#define MAX_LBL_SIZE 63 82#define MAX_LBL_SIZE 63
71#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
72 84
73#define RR_TYPE_A 1 85#define RR_TYPE_A 1
74#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
75#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
76#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
77 90
78#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
79 92
80#define CMD_IP_1 207 93#define CMD_IP_1 207
81#define CMD_IP_2 46 94#define CMD_IP_2 46
82#define CMD_IP_3 236 95#define CMD_IP_3 236
83#define CMD_IP_RST 29 96
84#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
85#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}
86 113
87// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
88struct charmap 115struct charmap
89{ 116{
90 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
104 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
105 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
106 133
107 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
108 { 135 {
136 char c = cmap [size];
137
109 enc [size] = cmap [size]; 138 enc [size] = c;
110 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;
111 } 144 }
112 145
113 assert (size < 256); 146 assert (size < 256);
114} 147}
115 148
… …
122{ 155{
123 charmap cmap; 156 charmap cmap;
124 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
125 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
126 159
127 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
128 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
129 162
130 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
131 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
132 165
133 basecoder (const char *cmap); 166 basecoder (const char *cmap);
134}; 167};
135 168
136basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
155 enc_len [len] = n; 188 enc_len [len] = n;
156 dec_len [n] = len; 189 dec_len [n] = len;
157 } 190 }
158} 191}
159 192
193unsigned int
160unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
161{ 195{
162 return enc_len [len]; 196 return enc_len [len];
163} 197}
164 198
199unsigned int
165unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
166{ 201{
167 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
168 --len; 203 --len;
169 204
170 return dec_len [len]; 205 return dec_len [len];
171} 206}
172 207
208unsigned int
173unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
174{ 210{
175 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
176 return 0; 212 return 0;
177 213
178 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
197 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
198 234
199 return elen; 235 return elen;
200} 236}
201 237
238unsigned int
202unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
203{ 240{
204 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
205 return 0; 242 return 0;
206 243
207 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
256 } 293 }
257 abort (); 294 abort ();
258} 295}
259#endif 296#endif
260 297
261//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
262//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
263static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
264//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
265static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
266 301
267///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
268 303
269#define HDRSIZE 6 304#define HDRSIZE 5
270 305
306inline void
271inline void encode_header (char *data, int clientid, int seqno) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
272{ 308{
273 u8 hdr[3] = { clientid, seqno >> 8, seqno };
274
275 assert (clientid < 256); 309 assert (clientid < 256);
276 310
311 seqno &= SEQNO_MASK;
312
313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
316 clientid,
317 };
318
277 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
278} 320}
279 321
322inline void
280inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
281{ 324{
282 u8 hdr[3]; 325 u8 hdr[3];
283 326
284 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
285 328
286 clientid = hdr[0]; 329 clientid = hdr[2];
287 seqno = (hdr[1] << 8) | hdr[2]; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
288} 331}
289 332
290///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
291 334
292struct byte_stream 335struct byte_stream
… …
318byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
319{ 362{
320 delete data; 363 delete data;
321} 364}
322 365
366void
323void byte_stream::remove (int count) 367byte_stream::remove (int count)
324{ 368{
325 if (count > fill) 369 if (count > fill)
326 abort (); 370 assert (count <= fill);
327 371
328 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
329} 373}
330 374
375bool
331bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
332{ 377{
333 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
334 return false; 379 return false;
335 380
336 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
337 382
338 return true; 383 return true;
339} 384}
340 385
386bool
341bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
342{ 388{
343 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
344 return false; 390 return false;
345 391
346 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
… …
351 return true; 397 return true;
352} 398}
353 399
354vpn_packet *byte_stream::get () 400vpn_packet *byte_stream::get ()
355{ 401{
402 unsigned int len;
403
404 for (;;)
405 {
356 int len = (data [0] << 8) | data [1]; 406 len = (data [0] << 8) | data [1];
357 407
358 if (len > MAXSIZE && fill >= 2) 408 if (len <= MAXSIZE || fill < 2)
359 abort (); // TODO handle this gracefully, connection reset 409 break;
360 410
411 // TODO: handle this better than skipping, e.g. by reset
412 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
413 remove (1);
414 }
415
361 if (fill < len + 2) 416 if (fill < len + 2)
362 return 0; 417 return 0;
363 418
364 vpn_packet *pkt = new vpn_packet; 419 vpn_packet *pkt = new vpn_packet;
365 420
… …
393 448
394struct dns_cfg 449struct dns_cfg
395{ 450{
396 static int next_uid; 451 static int next_uid;
397 452
453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
456
457 u8 version;
458 u8 flags;
459 u16 max_size;
460
398 u8 id1, id2, id3, id4; 461 u8 id1, id2, id3, id4;
399 u8 version; 462
400 u8 rrtype; 463 u16 client;
401 u8 flags;
402 u8 def_ttl; 464 u8 def_ttl;
403 u8 rcv_cdc; 465 u8 r0;
404 u8 snd_cdc;
405 u16 max_size;
406 u16 client;
407 u16 uid; // to make request unique
408 466
409 u8 reserved[8]; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
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
471
472 u8 r1, r2, r3, r4;
410 473
411 void reset (int clientid); 474 void reset (int clientid);
412 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
413}; 477};
414 478
415int dns_cfg::next_uid; 479int dns_cfg::next_uid;
416 480
481void
417void dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
418{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
419 id1 = 'G'; 485 id1 = 'G';
420 id2 = 'V'; 486 id2 = 'V';
421 id3 = 'P'; 487 id3 = 'P';
422 id4 = 'E'; 488 id4 = 'E';
423 489
424 version = 1; 490 version = 2;
425 491
426 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
427 flags = 0; 493 flags = 0;
428 def_ttl = 0; 494 def_ttl = 0;
429 rcv_cdc = 0;
430 snd_cdc = 62; 495 syn_cdc = 26;
496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
498 rep_cdc = 0;
431 max_size = ntohs (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
432 client = ntohs (clientid); 500 client = htons (clientid);
433 uid = next_uid++; 501 uid = ++next_uid;
434 502
435 memset (reserved, 0, 8); 503 r0 = r1 = r2 = r3 = r4 = 0;
436}
437 504
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
438bool dns_cfg::valid () 526dns_cfg::valid ()
439{ 527{
528 // although the protocol itself allows for some configurability,
529 // only the following encoding/decoding settings are implemented.
440 return id1 == 'G' 530 return id1 == 'G'
441 && id2 == 'V' 531 && id2 == 'V'
442 && id3 == 'P' 532 && id3 == 'P'
443 && id4 == 'E' 533 && id4 == 'E'
444 && version == 1 534 && version == 2
445 && flags == 0
446 && rcv_cdc == 0
447 && snd_cdc == 62 535 && syn_cdc == 26
448 && max_size == ntohs (MAX_PKT_SIZE); 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
538 && rep_cdc == 0
539 && chksum == get_chksum ();
449} 540}
450 541
451struct dns_packet : net_packet 542struct dns_packet : net_packet
452{ 543{
453 u16 id; 544 u16 id;
454 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 545 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
455 u16 qdcount, ancount, nscount, arcount; 546 u16 qdcount, ancount, nscount, arcount;
456 547
457 u8 data[MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
458 549
459 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
460}; 551};
461 552
553int
462int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
463{ 555{
464 char *orig = data; 556 char *orig = data;
465 557
466 memset (data, 0, size); 558 memset (data, 0, size);
467 559
… …
493 return data - orig; 585 return data - orig;
494} 586}
495 587
496///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
497 589
498struct dns_snd 590static
591u16 next_id ()
499{ 592{
500 dns_packet *pkt;
501 tstamp timeout, sent;
502 int retry;
503 struct dns_connection *dns;
504 int seqno;
505
506 dns_snd (dns_connection *dns);
507 void gen_stream_req (int seqno, byte_stream &stream);
508 void gen_syn_req (const dns_cfg &cfg);
509};
510
511static u16 dns_id = 12098; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
512 594
513static u16 next_id () 595#if 1
514{ 596 if (!dns_id)
597 dns_id = time (0);
598
515 // the simplest lsfr with periodicity 65535 i could find 599 // the simplest lsfr with periodicity 65535 i could find
516 dns_id = (dns_id << 1) 600 dns_id = (dns_id << 1)
517 | (((dns_id >> 1) 601 | (((dns_id >> 1)
518 ^ (dns_id >> 2) 602 ^ (dns_id >> 2)
519 ^ (dns_id >> 4) 603 ^ (dns_id >> 4)
520 ^ (dns_id >> 15)) & 1); 604 ^ (dns_id >> 15)) & 1);
521 605
522 return dns_id; 606 return dns_id;
607#else
608 dns_id++;//D
609
610 return htons (dns_id);
611#endif
523} 612}
613
614struct dns_rcv;
615struct dns_snd;
616
617struct dns_connection
618{
619 connection *c;
620 struct vpn *vpn;
621
622 dns_cfg cfg;
623
624 bool established;
625 const basecoder *cdc;
626
627 tstamp last_received;
628 tstamp last_sent;
629 double min_latency;
630 double poll_interval, send_interval;
631
632 vector<dns_rcv *> rcvpq;
633
634 byte_stream rcvdq; int rcvseq; int repseq;
635 byte_stream snddq; int sndseq;
636
637 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
638 void receive_rep (dns_rcv *r);
639
640 void reset (); // quite like tcp RST
641 void set_cfg (); // to be called after any cfg changes
642
643 dns_connection (connection *c);
644 ~dns_connection ();
645};
646
647struct dns_snd
648{
649 dns_packet *pkt;
650 tstamp timeout, sent;
651 int retry;
652 struct dns_connection *dns;
653 int seqno;
654 bool stdhdr;
655
656 void gen_stream_req (int seqno, byte_stream &stream);
657 void gen_syn_req ();
658
659 dns_snd (dns_connection *dns);
660 ~dns_snd ();
661};
524 662
525dns_snd::dns_snd (dns_connection *dns) 663dns_snd::dns_snd (dns_connection *dns)
526: dns (dns) 664: dns (dns)
527{ 665{
528 timeout = 0; 666 timeout = 0;
529 retry = 0; 667 retry = 0;
530 seqno = 0; 668 seqno = 0;
669 sent = ev_now ();
670 stdhdr = false;
531 671
532 pkt = new dns_packet; 672 pkt = new dns_packet;
533 673
534 pkt->id = next_id (); 674 pkt->id = next_id ();
535} 675}
536 676
677dns_snd::~dns_snd ()
678{
679 delete pkt;
680}
681
682static void
537static void append_domain (dns_packet &pkt, int &offs, const char *domain) 683append_domain (dns_packet &pkt, int &offs, const char *domain)
538{ 684{
539 // add tunnel domain 685 // add tunnel domain
540 for (;;) 686 for (;;)
541 { 687 {
542 const char *end = strchr (domain, '.'); 688 const char *end = strchr (domain, '.');
… …
555 701
556 domain = end + 1; 702 domain = end + 1;
557 } 703 }
558} 704}
559 705
706void
560void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 707dns_snd::gen_stream_req (int seqno, byte_stream &stream)
561{ 708{
709 stdhdr = true;
562 this->seqno = seqno; 710 this->seqno = seqno;
563 711
564 timeout = NOW + INITIAL_TIMEOUT; 712 timeout = ev_now () + INITIAL_TIMEOUT;
565 713
566 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 714 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
567 pkt->qdcount = htons (1); 715 pkt->qdcount = htons (1);
568 716
569 int offs = 6*2; 717 int offs = 6*2;
570 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 718 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
571 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 719 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
572 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 720 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
573 721
574 char enc[256], *encp = enc; 722 char enc[256], *encp = enc;
575 encode_header (enc, THISNODE->id, seqno); 723 encode_header (enc, THISNODE->id, seqno);
576 724
577 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 725 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
578 726
579 if (datalen > stream.size ()) 727 if (datalen > stream.size ())
580 datalen = stream.size (); 728 datalen = stream.size ();
581 729
582 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 730 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
583 stream.remove (datalen); 731 stream.remove (datalen);
584 732
585 while (enclen) 733 while (enclen)
586 { 734 {
587 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 735 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
593 encp += lbllen; 741 encp += lbllen;
594 742
595 enclen -= lbllen; 743 enclen -= lbllen;
596 } 744 }
597 745
598 append_domain (*pkt, offs, THISNODE->domain); 746 append_domain (*pkt, offs, dns->c->conf->domain);
599 747
600 (*pkt)[offs++] = 0; 748 (*pkt)[offs++] = 0;
601 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 749 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
602 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 750 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
603 751
604 pkt->len = offs; 752 pkt->len = offs;
605} 753}
606 754
607void dns_snd::gen_syn_req (const dns_cfg &cfg) 755void
756dns_snd::gen_syn_req ()
608{ 757{
609 timeout = NOW + INITIAL_SYN_TIMEOUT; 758 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
610 759
611 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 760 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
612 pkt->qdcount = htons (1); 761 pkt->qdcount = htons (1);
613 762
614 int offs = 6*2; 763 int offs = 6 * 2;
615 764
616 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); 765 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg));
617 766
618 assert (elen <= MAX_LBL_SIZE); 767 assert (elen <= MAX_LBL_SIZE);
619 768
620 (*pkt)[offs] = elen; 769 (*pkt)[offs] = elen;
621 offs += elen + 1; 770 offs += elen + 1;
622 append_domain (*pkt, offs, THISNODE->domain); 771 append_domain (*pkt, offs, dns->c->conf->domain);
623 772
624 (*pkt)[offs++] = 0; 773 (*pkt)[offs++] = 0;
625 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 774 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
626 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 775 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
627 776
… …
650 delete pkt; 799 delete pkt;
651} 800}
652 801
653///////////////////////////////////////////////////////////////////////////// 802/////////////////////////////////////////////////////////////////////////////
654 803
655struct dns_connection
656{
657 connection *c;
658 struct vpn *vpn;
659
660 dns_cfg cfg;
661
662 bool established;
663
664 tstamp last_received;
665 tstamp last_sent;
666 double poll_interval, send_interval;
667
668 vector<dns_rcv *> rcvpq;
669
670 byte_stream rcvdq; int rcvseq;
671 byte_stream snddq; int sndseq;
672
673 void time_cb (time_watcher &w); time_watcher tw;
674 void receive_rep (dns_rcv *r);
675
676 dns_connection (connection *c);
677 ~dns_connection ();
678};
679
680dns_connection::dns_connection (connection *c) 804dns_connection::dns_connection (connection *c)
681: c (c) 805: c (c)
682, rcvdq (MAX_BACKLOG * 2) 806, rcvdq (MAX_BACKLOG * 2)
683, snddq (MAX_BACKLOG * 2) 807, snddq (MAX_BACKLOG)
684, tw (this, &dns_connection::time_cb)
685{ 808{
809 tw.set<dns_connection, &dns_connection::time_cb> (this);
810
686 vpn = c->vpn; 811 vpn = c->vpn;
687 812
813 reset ();
814}
815
816dns_connection::~dns_connection ()
817{
818 reset ();
819}
820
821void
822dns_connection::reset ()
823{
824 while (!rcvpq.empty ())
825 {
826 delete rcvpq.back ();
827 rcvpq.pop_back ();
828 }
829
830 for (int i = vpn->dns_sndpq.size (); i--; )
831 if (vpn->dns_sndpq [i]->dns == this)
832 {
833 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
834 vpn->dns_sndpq.pop_back ();
835 }
836
688 established = false; 837 established = false;
689 838
690 rcvseq = sndseq = 0; 839 rcvseq = repseq = sndseq = 0;
691 840
692 last_sent = last_received = 0; 841 last_sent = 0;
693 poll_interval = MIN_POLL_INTERVAL; 842 poll_interval = 0.5; // starting here
694 send_interval = 0.2; // starting rate 843 send_interval = 0.5; // starting rate
844 min_latency = INITIAL_TIMEOUT;
695} 845}
696 846
697dns_connection::~dns_connection () 847void
848dns_connection::set_cfg ()
698{ 849{
699 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 850 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
700 i != rcvpq.end ();
701 ++i)
702 delete *i;
703} 851}
704 852
853void
705void dns_connection::receive_rep (dns_rcv *r) 854dns_connection::receive_rep (dns_rcv *r)
706{ 855{
707 if (r->datalen) 856 if (r->datalen)
708 { 857 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
709 last_received = NOW;
710 tw.trigger ();
711
712 poll_interval *= 0.99;
713 if (poll_interval > MIN_POLL_INTERVAL)
714 poll_interval = MIN_POLL_INTERVAL;
715 }
716 else 858 else
717 { 859 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
718 poll_interval *= 1.1;
719 if (poll_interval > MAX_POLL_INTERVAL)
720 poll_interval = MAX_POLL_INTERVAL;
721 }
722 860
723 rcvpq.push_back (r); 861 rcvpq.push_back (r);
724 862
725 redo: 863 redo:
726 864
727 // find next packet 865 // find next packet
728 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 866 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
729 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 867 if (SEQNO_EQ (rcvseq, (*i)->seqno))
730 { 868 {
869 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
731 // enter the packet into our input stream 870 // enter the packet into our input stream
732 r = *i; 871 r = *i;
733 872
734 // remove the oldest packet, look forward, as it's oldest first 873 // remove the oldest packet, look forward, as it's oldest first
735 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 874 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
736 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 875 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
737 { 876 {
877 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
738 delete *j; 878 delete *j;
739 rcvpq.erase (j); 879 rcvpq.erase (j);
740 break; 880 break;
741 } 881 }
742 882
743 rcvseq = (rcvseq + 1) & SEQNO_MASK; 883 rcvseq = (rcvseq + 1) & SEQNO_MASK;
744 884
745 if (!rcvdq.put (r->data, r->datalen)) 885 if (!rcvdq.put (r->data, r->datalen))
886 {
746 abort (); // MUST never overflow, can be caused by data corruption, TODO 887 // MUST never overflow, can be caused by data corruption, TODO
888 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
889 reset ();
890 return;
891 }
747 892
748 while (vpn_packet *pkt = rcvdq.get ()) 893 while (vpn_packet *pkt = rcvdq.get ())
749 { 894 {
750 sockinfo si; 895 sockinfo si;
751 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 896 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
752 897
753 vpn->recv_vpn_packet (pkt, si); 898 vpn->recv_vpn_packet (pkt, si);
899 delete pkt;
754 } 900 }
755 901
756 // check for further packets 902 // check for further packets
757 goto redo; 903 goto redo;
758 } 904 }
… …
768 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 914 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
769 915
770 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 916 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
771 && pkt.qdcount == htons (1)) 917 && pkt.qdcount == htons (1))
772 { 918 {
773 char qname[MAXSIZE]; 919 char qname [MAXSIZE];
774 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 920 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
775 921
776 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 922 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
777 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 923 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
778 924
779 pkt.qdcount = htons (1); 925 pkt.qdcount = htons (1);
780 pkt.ancount = 0; 926 pkt.ancount = 0;
781 pkt.nscount = 0; // should be self, as other nameservers reply like this 927 pkt.nscount = 0; // should be self, as other nameservers reply like this
782 pkt.arcount = 0; // a record for self, as other nameservers reply like this 928 pkt.arcount = 0; // a record for self, as other nameservers reply like this
783 929
784 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_NXDOMAIN); 930 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_SERVFAIL);
785 931
786 int dlen = strlen (THISNODE->domain); 932 int dlen = strlen (THISNODE->domain);
787 933
788 if (qclass == RR_CLASS_IN 934 if (qclass == RR_CLASS_IN
789 && qlen > dlen + 1 935 && qlen > dlen + 1
790 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 936 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
791 { 937 {
792 // now generate reply 938 // now generate reply
793 pkt.ancount = htons (1); // one answer RR 939 pkt.ancount = htons (1); // one answer RR
794 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 940 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
795 941
… …
800 { 946 {
801 // correct class, domain: parse 947 // correct class, domain: parse
802 int client, seqno; 948 int client, seqno;
803 decode_header (qname, client, seqno); 949 decode_header (qname, client, seqno);
804 950
805 u8 data[MAXSIZE];
806 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
807
808 if (0 < client && client <= conns.size ()) 951 if (0 < client && client <= conns.size ())
809 { 952 {
810 connection *c = conns [client - 1]; 953 connection *c = conns [client - 1];
811 dns_connection *dns = c->dns; 954 dns_connection *dns = c->dns;
812 dns_rcv *rcv; 955 dns_rcv *rcv;
813 956
814 if (dns) 957 if (dns)
815 { 958 {
959 u8 data[MAXSIZE];
960 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
961
816 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 962 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
817 if (SEQNO_EQ ((*i)->seqno, seqno)) 963 if (SEQNO_EQ ((*i)->seqno, seqno))
818 { 964 {
819 // already seen that request: simply reply with the cached reply 965 // already seen that request: simply reply with the cached reply
820 dns_rcv *r = *i; 966 dns_rcv *r = *i;
821 967
822 printf ("DUPLICATE %d\n", htons (r->pkt->id));//D 968 slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
969
970 // refresh header & id, as the retry count could have changed
971 memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
972 r->pkt->id = pkt.id;
823 973
824 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 974 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
825 pkt.id = r->pkt->id; 975
826 goto duplicate_request; 976 goto duplicate_request;
827 } 977 }
828 978
829 // new packet, queue 979 // new packet, queue
830 rcv = new dns_rcv (seqno, data, datalen); 980 rcv = new dns_rcv (seqno, data, datalen);
831 dns->receive_rep (rcv); 981 dns->receive_rep (rcv);
832 } 982 }
833 983
984 {
834 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 985 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
835 986
836 // type
837 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 987 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
838 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; 988 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
839
840 // class
841 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; 989 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
842
843 // TTL
844 pkt [offs++] = 0; pkt [offs++] = 0; 990 pkt [offs++] = 0; pkt [offs++] = 0;
845 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; 991 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
846 992
847 int rdlen_offs = offs += 2; 993 int rdlen_offs = offs += 2;
848 994
995 if (dns)
996 {
849 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 997 int dlen = ntohs (dns->cfg.max_size) - offs;
998
850 // bind doesn't compress well, so reduce further by one label length 999 // bind doesn't compress well, so reduce further by one label length
851 dlen -= qlen; 1000 dlen -= qlen;
852 1001
853 if (dns) 1002 // only put data into in-order sequence packets, if
854 { 1003 // we receive out-of-order packets we generate empty
855 while (dlen > 1 && !dns->snddq.empty ()) 1004 // replies
1005 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
1006 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
856 { 1007 {
1008 dns->repseq = seqno;
1009
1010 while (dlen > 1 && !dns->snddq.empty ())
1011 {
857 int txtlen = dlen <= 255 ? dlen - 1 : 255; 1012 int txtlen = dlen <= 255 ? dlen - 1 : 255;
858 1013
859 if (txtlen > dns->snddq.size ()) 1014 if (txtlen > dns->snddq.size ())
860 txtlen = dns->snddq.size (); 1015 txtlen = dns->snddq.size ();
861 1016
862 pkt[offs++] = txtlen; 1017 pkt[offs++] = txtlen;
863 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 1018 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
864 offs += txtlen; 1019 offs += txtlen;
865 dns->snddq.remove (txtlen); 1020 dns->snddq.remove (txtlen);
866 1021
867 dlen -= txtlen + 1; 1022 dlen -= txtlen + 1;
1023 }
868 } 1024 }
869 1025
870 // avoid empty TXT rdata 1026 // avoid completely empty TXT rdata
871 if (offs == rdlen_offs) 1027 if (offs == rdlen_offs)
872 pkt[offs++] = 0; 1028 pkt[offs++] = 0;
1029
1030 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
873 } 1031 }
874 else 1032 else
875 { 1033 {
876 // send RST 1034 // send RST
877 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1035 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
878 pkt [offs++] = CMD_IP_RST; 1036 pkt [offs++] = CMD_IP_RST;
879 } 1037 }
880 1038
881 int rdlen = offs - rdlen_offs; 1039 int rdlen = offs - rdlen_offs;
882 1040
883 pkt [rdlen_offs - 2] = rdlen >> 8; 1041 pkt [rdlen_offs - 2] = rdlen >> 8;
884 pkt [rdlen_offs - 1] = rdlen; 1042 pkt [rdlen_offs - 1] = rdlen;
885 1043
886 if (dns) 1044 if (dns)
887 { 1045 {
888 // now update dns_rcv copy 1046 // now update dns_rcv copy
889 rcv->pkt->len = offs; 1047 rcv->pkt->len = offs;
890 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 1048 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
891 } 1049 }
1050 }
892 1051
893 duplicate_request: ; 1052 duplicate_request: ;
894 } 1053 }
895 else 1054 else
896 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 1055 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
908 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1067 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
909 pkt [offs++] = 0; pkt [offs++] = 0; 1068 pkt [offs++] = 0; pkt [offs++] = 0;
910 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1069 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
911 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1070 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
912 1071
913 slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);
914
915 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1072 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
916 pkt [offs++] = CMD_IP_REJ; 1073 pkt [offs++] = CMD_IP_REJ;
917 1074
918 if (0 < client && client <= conns.size ()) 1075 if (0 < client && client <= conns.size ())
919 { 1076 {
920 connection *c = conns [client - 1]; 1077 connection *c = conns [client - 1];
921 1078
922 if (cfg.valid ()) 1079 if (cfg.valid ())
923 { 1080 {
924 pkt [offs - 1] = CMD_IP_SYN; 1081 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1082
1083 // check for any encoding mismatches - hints at a case problem
1084 char qname2 [MAX_ENC_LEN];
1085 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
925 1086
926 delete c->dns; 1087 delete c->dns;
1088
1089 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1090 ? CMD_IP_CSE : CMD_IP_SYN;
1091
927 c->dns = new dns_connection (c); 1092 c->dns = new dns_connection (c);
928 c->dns->cfg = cfg; 1093 c->dns->cfg = cfg;
1094 c->dns->set_cfg ();
929 } 1095 }
930 } 1096 }
931 } 1097 }
932 } 1098 }
933 1099
… …
949 i != dns_sndpq.end (); 1115 i != dns_sndpq.end ();
950 ++i) 1116 ++i)
951 if ((*i)->pkt->id == pkt.id) 1117 if ((*i)->pkt->id == pkt.id)
952 { 1118 {
953 dns_connection *dns = (*i)->dns; 1119 dns_connection *dns = (*i)->dns;
1120 connection *c = dns->c;
954 int seqno = (*i)->seqno; 1121 int seqno = (*i)->seqno;
955 u8 data[MAXSIZE], *datap = data; 1122 u8 data[MAXSIZE], *datap = data;
1123 //printf ("rcv pkt %x\n", seqno);//D
956 1124
957 if ((*i)->retry) 1125 if ((*i)->retry)
958 { 1126 {
959 dns->send_interval *= 1.01; 1127 dns->send_interval *= 1.01;
960 if (dns->send_interval < MAX_SEND_INTERVAL) 1128 if (dns->send_interval > MAX_SEND_INTERVAL)
961 dns->send_interval = MAX_SEND_INTERVAL; 1129 dns->send_interval = MAX_SEND_INTERVAL;
962 } 1130 }
963 else 1131 else
964 { 1132 {
1133#if 0
965 dns->send_interval *= 0.99; 1134 dns->send_interval *= 0.999;
966 if (dns->send_interval < MIN_SEND_INTERVAL) 1135#endif
967 dns->send_interval = MIN_SEND_INTERVAL;
968
969 // the latency surely puts an upper bound on 1136 // the latency surely puts an upper bound on
970 // the minimum send interval 1137 // the minimum send interval
971 if (dns->send_interval > NOW - (*i)->sent) 1138 double latency = ev_now () - (*i)->sent;
972 dns->send_interval = NOW - (*i)->sent; 1139
1140 if (latency < dns->min_latency)
1141 dns->min_latency = latency;
1142
1143 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1144 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1145
1146 if (dns->send_interval < conf.dns_send_interval)
1147 dns->send_interval = conf.dns_send_interval;
973 } 1148 }
974 1149
975 delete *i; 1150 delete *i;
976 dns_sndpq.erase (i); 1151 dns_sndpq.erase (i);
977 1152
… …
995 ttl |= pkt [offs++] << 16; 1170 ttl |= pkt [offs++] << 16;
996 ttl |= pkt [offs++] << 8; 1171 ttl |= pkt [offs++] << 8;
997 ttl |= pkt [offs++]; 1172 ttl |= pkt [offs++];
998 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1173 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
999 1174
1000 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1175 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1001 { 1176 {
1002 if (rdlen <= MAXSIZE - offs) 1177 if (rdlen <= MAXSIZE - offs)
1003 { 1178 {
1004 // decode bytes, finally 1179 // decode bytes, finally
1005 1180
… …
1027 1202
1028 if (ip [0] == CMD_IP_1 1203 if (ip [0] == CMD_IP_1
1029 && ip [1] == CMD_IP_2 1204 && ip [1] == CMD_IP_2
1030 && ip [2] == CMD_IP_3) 1205 && ip [2] == CMD_IP_3)
1031 { 1206 {
1032 slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]); 1207 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1033 1208
1034 if (ip [3] == CMD_IP_RST) 1209 if (ip [3] == CMD_IP_RST)
1035 { 1210 {
1036 slog (L_DEBUG, _("got tunnel RST request")); 1211 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1037 1212
1038 connection *c = dns->c; 1213 dns->reset ();
1039 delete c->dns; c->dns = 0;
1040
1041 return; 1214 return;
1042 } 1215 }
1043 else if (ip [3] == CMD_IP_SYN) 1216 else if (ip [3] == CMD_IP_SYN)
1217 {
1218 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1044 dns->established = true; 1219 dns->established = true;
1220 }
1221 else if (ip [3] == CMD_IP_CSE)
1222 {
1223 if (conf.dns_case_preserving)
1224 {
1225 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1226 conf.dns_case_preserving = false;
1227 dns->reset ();
1228 return;
1229 }
1230 else
1231 {
1232 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1233 dns->established = true;
1234 }
1235 }
1236 else if (ip [3] == CMD_IP_REJ)
1237 {
1238 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1239 dns->tw.start (60.);
1240 }
1045 else 1241 else
1242 {
1046 slog (L_INFO, _("got unknown meta command %02x"), ip [3]); 1243 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1244 dns->tw.start (60.);
1245 }
1047 } 1246 }
1048 else 1247 else
1049 slog (L_INFO, _("got spurious a record %d.%d.%d.%d"), 1248 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1050 ip [0], ip [1], ip [2], ip [3]); 1249 ip [0], ip [1], ip [2], ip [3]);
1051 1250
1052 return; 1251 return;
1053 } 1252 }
1054 1253
1055 int client, rseqno; 1254 int client, rseqno;
1056 decode_header (qname, client, rseqno); 1255 decode_header (qname, client, rseqno);
1057 1256
1058 if (client != THISNODE->id) 1257 if (client != THISNODE->id)
1059 { 1258 {
1060 slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring")); 1259 slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1061 datap = 0; 1260 datap = 0;
1062 } 1261 }
1063 else if (rseqno != seqno) 1262 else if (rseqno != seqno)
1064 { 1263 {
1065 slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?")); 1264 slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
1066 datap = 0; 1265 datap = 0;
1067 } 1266 }
1068 } 1267 }
1069 } 1268 }
1070 1269
… …
1075 break; 1274 break;
1076 } 1275 }
1077} 1276}
1078 1277
1079void 1278void
1080vpn::dnsv4_ev (io_watcher &w, short revents) 1279vpn::dnsv4_ev (ev::io &w, int revents)
1081{ 1280{
1082 if (revents & EVENT_READ) 1281 if (revents & EV_READ)
1083 { 1282 {
1084 dns_packet *pkt = new dns_packet; 1283 dns_packet *pkt = new dns_packet;
1085 struct sockaddr_in sa; 1284 struct sockaddr_in sa;
1086 socklen_t sa_len = sizeof (sa); 1285 socklen_t sa_len = sizeof (sa);
1087 1286
1088 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1287 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1089 1288
1090 if (pkt->len > 0) 1289 if (pkt->len > 0)
1091 { 1290 {
1092 if (THISNODE->dns_port) 1291 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1292 dnsv4_client (*pkt);
1293 else
1093 { 1294 {
1094 dnsv4_server (*pkt); 1295 dnsv4_server (*pkt);
1095 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1296 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1096 } 1297 }
1097 else
1098 dnsv4_client (*pkt);
1099 1298
1100 delete pkt; 1299 delete pkt;
1101 } 1300 }
1102 } 1301 }
1103} 1302}
1104 1303
1105bool 1304bool
1106connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1305vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1107{ 1306{
1307 int client = ntohl (si.host);
1308
1309 assert (0 < client && client <= conns.size ());
1310
1311 connection *c = conns [client - 1];
1312
1108 if (!dns) 1313 if (!c->dns)
1109 dns = new dns_connection (this); 1314 c->dns = new dns_connection (c);
1110 1315
1111 if (!dns->snddq.put (pkt)) 1316 if (c->dns->snddq.put (pkt))
1112 return false; 1317 {
1318 min_it (c->dns->poll_interval, 0.25);
1319 c->dns->tw ();
1320 }
1113 1321
1114 dns->tw.trigger (); 1322 // always return true even if the buffer overflows
1115
1116 return true; 1323 return true;
1117} 1324}
1118 1325
1119#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1120
1121void 1326void
1122dns_connection::time_cb (time_watcher &w) 1327dns_connection::time_cb (ev::timer &w, int revents)
1123{ 1328{
1124 // servers have to be polled 1329 // servers have to be polled
1125 if (THISNODE->dns_port) 1330 if (THISNODE->dns_port)
1126 return; 1331 return;
1127 1332
1128 // check for timeouts and (re)transmit 1333 // check for timeouts and (re)transmit
1129 tstamp next = NOW + poll_interval; 1334 tstamp next = 86400 * 365;
1130 dns_snd *send = 0; 1335 dns_snd *send = 0;
1131 1336
1132 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1337 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1133 i != vpn->dns_sndpq.end (); 1338 i != vpn->dns_sndpq.end ();
1134 ++i) 1339 ++i)
1135 { 1340 {
1136 dns_snd *r = *i; 1341 dns_snd *r = *i;
1137 1342
1138 if (r->timeout <= NOW) 1343 if (r->timeout <= ev_now ())
1139 { 1344 {
1140 if (!send) 1345 if (!send)
1141 { 1346 {
1142 send = r; 1347 send = r;
1143 1348
1144 r->retry++; 1349 r->retry++;
1145 r->timeout = NOW + r->retry; 1350 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1351 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1352
1353 // the following code changes the query section a bit, forcing
1354 // the forwarder to generate a new request
1355 if (r->stdhdr)
1356 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1146 } 1357 }
1147 } 1358 }
1148 else if (r->timeout < next) 1359 else
1149 NEXT (r->timeout); 1360 min_it (next, r->timeout - ev_now ());
1150 }
1151
1152 if (last_sent + send_interval <= NOW)
1153 { 1361 }
1362
1154 if (!send) 1363 if (!send)
1364 {
1365 // generate a new packet, if wise
1366
1367 if (!established)
1155 { 1368 {
1156 // generate a new packet, if wise
1157
1158 if (!established)
1159 {
1160 if (vpn->dns_sndpq.empty ()) 1369 if (vpn->dns_sndpq.empty ())
1161 {
1162 send = new dns_snd (this);
1163
1164 cfg.reset (THISNODE->id);
1165 send->gen_syn_req (cfg);
1166 }
1167 }
1168 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
1169 { 1370 {
1170 send = new dns_snd (this); 1371 send = new dns_snd (this);
1372
1373 cfg.reset (THISNODE->id);
1374 set_cfg ();
1375 send->gen_syn_req ();
1376 }
1377 }
1378 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1379 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1380 {
1381 if (last_sent + send_interval <= ev_now ())
1382 {
1383 //printf ("sending data request etc.\n"); //D
1384 if (!snddq.empty ())
1385 min_it (next, send_interval);
1386
1387 send = new dns_snd (this);
1171 send->gen_stream_req (sndseq, snddq); 1388 send->gen_stream_req (sndseq, snddq);
1389 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1390 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1172 1391
1173 sndseq = (sndseq + 1) & SEQNO_MASK; 1392 sndseq = (sndseq + 1) & SEQNO_MASK;
1174 } 1393 }
1175 1394 else
1176 if (send) 1395 min_it (next, last_sent + send_interval - ev_now ());
1177 vpn->dns_sndpq.push_back (send);
1178 } 1396 }
1179 1397
1180 if (send) 1398 if (send)
1181 { 1399 vpn->dns_sndpq.push_back (send);
1182 printf ("send pkt\n"); 1400 }
1183 last_sent = NOW;
1184 1401
1185 if (!send->retry) 1402 if (send)
1186 send->sent = NOW; 1403 {
1187 1404 last_sent = ev_now ();
1188 sendto (vpn->dnsv4_fd, 1405 sendto (vpn->dnsv4_fd,
1189 send->pkt->at (0), send->pkt->len, 0, 1406 send->pkt->at (0), send->pkt->len, 0,
1190 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1407 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1191 }
1192 } 1408 }
1193 else
1194 NEXT (last_sent + send_interval);
1195 1409
1196 printf ("pi %f si %f N %f (%d:%d)\n", poll_interval, send_interval, next - NOW, vpn->dns_sndpq.size (), snddq.size ()); 1410 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1411
1412 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1413 poll_interval, send_interval, next - ev_now (),
1414 vpn->dns_sndpq.size (), snddq.size (),
1415 rcvpq.size ());
1197 1416
1198 w.start (next); 1417 w.start (next);
1199} 1418}
1200 1419
1201#endif 1420#endif

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