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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.37 by pcg, Wed Mar 23 17:03:58 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
… …
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 66
52#define INITIAL_TIMEOUT 0.1 // 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 MAX_SEND_INTERVAL 2. // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
56 71
57#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
58#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
59 74
60#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
61// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
62// every request byte less give room for two reply bytes 77// every request byte less give room for two reply bytes
63 78
64#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
65#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
… …
68#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
69 84
70#define RR_TYPE_A 1 85#define RR_TYPE_A 1
71#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
72#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
73#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
74 90
75#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
76 92
77#define CMD_IP_1 207 93#define CMD_IP_1 207
78#define CMD_IP_2 46 94#define CMD_IP_2 46
79#define CMD_IP_3 236 95#define CMD_IP_3 236
80#define CMD_IP_RST 29 96
81#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
82#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}
83 113
84// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
85struct charmap 115struct charmap
86{ 116{
87 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
101 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
102 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
103 133
104 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
105 { 135 {
136 char c = cmap [size];
137
106 enc [size] = cmap [size]; 138 enc [size] = c;
107 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;
108 } 144 }
109 145
110 assert (size < 256); 146 assert (size < 256);
111} 147}
112 148
… …
119{ 155{
120 charmap cmap; 156 charmap cmap;
121 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
122 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
123 159
124 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
125 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
126 162
127 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
128 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
129 165
130 basecoder (const char *cmap); 166 basecoder (const char *cmap);
131}; 167};
132 168
133basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
152 enc_len [len] = n; 188 enc_len [len] = n;
153 dec_len [n] = len; 189 dec_len [n] = len;
154 } 190 }
155} 191}
156 192
193unsigned int
157unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
158{ 195{
159 return enc_len [len]; 196 return enc_len [len];
160} 197}
161 198
199unsigned int
162unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
163{ 201{
164 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
165 --len; 203 --len;
166 204
167 return dec_len [len]; 205 return dec_len [len];
168} 206}
169 207
208unsigned int
170unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
171{ 210{
172 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
173 return 0; 212 return 0;
174 213
175 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
194 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
195 234
196 return elen; 235 return elen;
197} 236}
198 237
238unsigned int
199unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
200{ 240{
201 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
202 return 0; 242 return 0;
203 243
204 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
253 } 293 }
254 abort (); 294 abort ();
255} 295}
256#endif 296#endif
257 297
258//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
259//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
260static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
261//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
262static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
263 301
264///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
265 303
266#define HDRSIZE 6 304#define HDRSIZE 5
267 305
306inline void
268inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
269{ 308{
309 assert (clientid < 256);
310
270 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
271 312
272 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
273 clientid, 316 clientid,
274 (seqno >> 8) | (retry << 6),
275 seqno,
276 }; 317 };
277 318
278 assert (clientid < 256);
279
280 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
281} 320}
282 321
322inline void
283inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
284{ 324{
285 u8 hdr[3]; 325 u8 hdr[3];
286 326
287 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
288 328
289 clientid = hdr[0]; 329 clientid = hdr[2];
290 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
291} 331}
292 332
293///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
294 334
295struct byte_stream 335struct byte_stream
… …
321byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
322{ 362{
323 delete data; 363 delete data;
324} 364}
325 365
366void
326void byte_stream::remove (int count) 367byte_stream::remove (int count)
327{ 368{
328 if (count > fill) 369 if (count > fill)
329 assert (count <= fill); 370 assert (count <= fill);
330 371
331 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
332} 373}
333 374
375bool
334bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
335{ 377{
336 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
337 return false; 379 return false;
338 380
339 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
340 382
341 return true; 383 return true;
342} 384}
343 385
386bool
344bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
345{ 388{
346 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
347 return false; 390 return false;
348 391
349 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
… …
405 448
406struct dns_cfg 449struct dns_cfg
407{ 450{
408 static int next_uid; 451 static int next_uid;
409 452
410 u8 id1, id2, id3, id4; 453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
411 456
412 u8 version; 457 u8 version;
413 u8 flags; 458 u8 flags;
414 u8 rrtype; 459 u16 max_size;
460
461 u8 id1, id2, id3, id4;
462
463 u16 client;
415 u8 def_ttl; 464 u8 def_ttl;
465 u8 r0;
416 466
417 u16 client; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
418 u16 uid; // to make request unique 468 u8 hdr_cdc; // cdc en/decoder for regular request headers
469 u8 req_cdc; // cdc en/decoder for regular (ANY?) request data
470 u8 rep_cdc; // cdc en/decoder for regular (TXT) replies, 0 == 8 bit encoding
419 471
420 u16 max_size;
421 u8 seq_cdc;
422 u8 req_cdc;
423
424 u8 rep_cdc;
425 u8 delay; // time in 0.01s units that the server may delay replying packets
426 u8 r3, r4;
427
428 u8 r5, r6, r7, r8; 472 u8 r1, r2, r3, r4;
429 473
430 void reset (int clientid); 474 void reset (int clientid);
431 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
432}; 477};
433 478
434int dns_cfg::next_uid; 479int dns_cfg::next_uid;
435 480
481void
436void dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
437{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
438 id1 = 'G'; 485 id1 = 'G';
439 id2 = 'V'; 486 id2 = 'V';
440 id3 = 'P'; 487 id3 = 'P';
441 id4 = 'E'; 488 id4 = 'E';
442 489
443 version = 1; 490 version = 2;
444 491
445 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
446 flags = 0; 493 flags = 0;
447 def_ttl = 0; 494 def_ttl = 0;
448 seq_cdc = 26; 495 syn_cdc = 26;
449 req_cdc = 62; 496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
450 rep_cdc = 0; 498 rep_cdc = 0;
451 max_size = htons (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
452 client = htons (clientid); 500 client = htons (clientid);
453 uid = next_uid++; 501 uid = ++next_uid;
454 delay = 0;
455 502
456 r3 = r4 = 0; 503 r0 = r1 = r2 = r3 = r4 = 0;
457 r4 = r5 = r6 = r7 = 0;
458}
459 504
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
460bool dns_cfg::valid () 526dns_cfg::valid ()
461{ 527{
528 // although the protocol itself allows for some configurability,
529 // only the following encoding/decoding settings are implemented.
462 return id1 == 'G' 530 return id1 == 'G'
463 && id2 == 'V' 531 && id2 == 'V'
464 && id3 == 'P' 532 && id3 == 'P'
465 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
466 && seq_cdc == 26 535 && syn_cdc == 26
467 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
468 && rep_cdc == 0 538 && rep_cdc == 0
469 && version == 1; 539 && chksum == get_chksum ();
470} 540}
471 541
472struct dns_packet : net_packet 542struct dns_packet : net_packet
473{ 543{
474 u16 id; 544 u16 id;
… …
478 u8 data [MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
479 549
480 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
481}; 551};
482 552
553int
483int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
484{ 555{
485 char *orig = data; 556 char *orig = data;
486 557
487 memset (data, 0, size); 558 memset (data, 0, size);
488 559
… …
514 return data - orig; 585 return data - orig;
515} 586}
516 587
517///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
518 589
590static
591u16 next_id ()
592{
519static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
520 594
521static u16 next_id () 595#if 1
522{
523 if (!dns_id) 596 if (!dns_id)
524 dns_id = time (0); 597 dns_id = time (0);
525 598
526 // the simplest lsfr with periodicity 65535 i could find 599 // the simplest lsfr with periodicity 65535 i could find
527 dns_id = (dns_id << 1) 600 dns_id = (dns_id << 1)
… …
529 ^ (dns_id >> 2) 602 ^ (dns_id >> 2)
530 ^ (dns_id >> 4) 603 ^ (dns_id >> 4)
531 ^ (dns_id >> 15)) & 1); 604 ^ (dns_id >> 15)) & 1);
532 605
533 return dns_id; 606 return dns_id;
607#else
608 dns_id++;//D
609
610 return htons (dns_id);
611#endif
534} 612}
535 613
536struct dns_rcv; 614struct dns_rcv;
537struct dns_snd; 615struct dns_snd;
538 616
… …
542 struct vpn *vpn; 620 struct vpn *vpn;
543 621
544 dns_cfg cfg; 622 dns_cfg cfg;
545 623
546 bool established; 624 bool established;
625 const basecoder *cdc;
547 626
548 tstamp last_received; 627 tstamp last_received;
549 tstamp last_sent; 628 tstamp last_sent;
550 double min_latency; 629 double min_latency;
551 double poll_interval, send_interval; 630 double poll_interval, send_interval;
… …
553 vector<dns_rcv *> rcvpq; 632 vector<dns_rcv *> rcvpq;
554 633
555 byte_stream rcvdq; int rcvseq; int repseq; 634 byte_stream rcvdq; int rcvseq; int repseq;
556 byte_stream snddq; int sndseq; 635 byte_stream snddq; int sndseq;
557 636
558 void time_cb (time_watcher &w); time_watcher tw; 637 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
559 void receive_rep (dns_rcv *r); 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
560 642
561 dns_connection (connection *c); 643 dns_connection (connection *c);
562 ~dns_connection (); 644 ~dns_connection ();
563}; 645};
564 646
… …
582: dns (dns) 664: dns (dns)
583{ 665{
584 timeout = 0; 666 timeout = 0;
585 retry = 0; 667 retry = 0;
586 seqno = 0; 668 seqno = 0;
587 sent = NOW; 669 sent = ev_now ();
588 stdhdr = false; 670 stdhdr = false;
589 671
590 pkt = new dns_packet; 672 pkt = new dns_packet;
591 673
592 pkt->id = next_id (); 674 pkt->id = next_id ();
… …
595dns_snd::~dns_snd () 677dns_snd::~dns_snd ()
596{ 678{
597 delete pkt; 679 delete pkt;
598} 680}
599 681
682static void
600static void append_domain (dns_packet &pkt, int &offs, const char *domain) 683append_domain (dns_packet &pkt, int &offs, const char *domain)
601{ 684{
602 // add tunnel domain 685 // add tunnel domain
603 for (;;) 686 for (;;)
604 { 687 {
605 const char *end = strchr (domain, '.'); 688 const char *end = strchr (domain, '.');
… …
618 701
619 domain = end + 1; 702 domain = end + 1;
620 } 703 }
621} 704}
622 705
706void
623void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 707dns_snd::gen_stream_req (int seqno, byte_stream &stream)
624{ 708{
625 stdhdr = true; 709 stdhdr = true;
626 this->seqno = seqno; 710 this->seqno = seqno;
627 711
628 timeout = NOW + INITIAL_TIMEOUT; 712 timeout = ev_now () + INITIAL_TIMEOUT;
629 713
630 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 714 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
631 pkt->qdcount = htons (1); 715 pkt->qdcount = htons (1);
632 716
633 int offs = 6*2; 717 int offs = 6*2;
… …
636 // 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
637 721
638 char enc[256], *encp = enc; 722 char enc[256], *encp = enc;
639 encode_header (enc, THISNODE->id, seqno); 723 encode_header (enc, THISNODE->id, seqno);
640 724
641 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);
642 726
643 if (datalen > stream.size ()) 727 if (datalen > stream.size ())
644 datalen = stream.size (); 728 datalen = stream.size ();
645 729
646 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 730 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
647 stream.remove (datalen); 731 stream.remove (datalen);
648 732
649 while (enclen) 733 while (enclen)
650 { 734 {
651 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 735 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
666 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 750 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
667 751
668 pkt->len = offs; 752 pkt->len = offs;
669} 753}
670 754
755void
671void dns_snd::gen_syn_req () 756dns_snd::gen_syn_req ()
672{ 757{
673 timeout = NOW + INITIAL_SYN_TIMEOUT; 758 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
674 759
675 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 760 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
676 pkt->qdcount = htons (1); 761 pkt->qdcount = htons (1);
677 762
678 int offs = 6 * 2; 763 int offs = 6 * 2;
… …
718 803
719dns_connection::dns_connection (connection *c) 804dns_connection::dns_connection (connection *c)
720: c (c) 805: c (c)
721, rcvdq (MAX_BACKLOG * 2) 806, rcvdq (MAX_BACKLOG * 2)
722, snddq (MAX_BACKLOG) 807, snddq (MAX_BACKLOG)
723, tw (this, &dns_connection::time_cb)
724{ 808{
809 tw.set<dns_connection, &dns_connection::time_cb> (this);
810
725 vpn = c->vpn; 811 vpn = c->vpn;
726 812
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
727 established = false; 837 established = false;
728 838
729 rcvseq = repseq = sndseq = 0; 839 rcvseq = repseq = sndseq = 0;
730 840
731 last_sent = last_received = 0; 841 last_sent = 0;
732 poll_interval = 0.5; // starting here 842 poll_interval = 0.5; // starting here
733 send_interval = 0.5; // starting rate 843 send_interval = 0.5; // starting rate
734 min_latency = INITIAL_TIMEOUT; 844 min_latency = INITIAL_TIMEOUT;
735} 845}
736 846
737dns_connection::~dns_connection () 847void
848dns_connection::set_cfg ()
738{ 849{
739 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 850 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
740 i != rcvpq.end ();
741 ++i)
742 delete *i;
743} 851}
744 852
853void
745void dns_connection::receive_rep (dns_rcv *r) 854dns_connection::receive_rep (dns_rcv *r)
746{ 855{
747 if (r->datalen) 856 if (r->datalen)
748 { 857 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
749 last_received = NOW;
750 tw.trigger ();
751
752 poll_interval = send_interval;
753 }
754 else 858 else
755 { 859 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
756 poll_interval *= 1.5;
757
758 if (poll_interval > MAX_POLL_INTERVAL)
759 poll_interval = MAX_POLL_INTERVAL;
760 }
761 860
762 rcvpq.push_back (r); 861 rcvpq.push_back (r);
763 862
764 redo: 863 redo:
765 864
766 // find next packet 865 // find next packet
767 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 866 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
768 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 867 if (SEQNO_EQ (rcvseq, (*i)->seqno))
769 { 868 {
869 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
770 // enter the packet into our input stream 870 // enter the packet into our input stream
771 r = *i; 871 r = *i;
772 872
773 // remove the oldest packet, look forward, as it's oldest first 873 // remove the oldest packet, look forward, as it's oldest first
774 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)
775 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 875 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
776 { 876 {
877 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
777 delete *j; 878 delete *j;
778 rcvpq.erase (j); 879 rcvpq.erase (j);
779 break; 880 break;
780 } 881 }
781 882
782 rcvseq = (rcvseq + 1) & SEQNO_MASK; 883 rcvseq = (rcvseq + 1) & SEQNO_MASK;
783 884
784 if (!rcvdq.put (r->data, r->datalen)) 885 if (!rcvdq.put (r->data, r->datalen))
785 { 886 {
887 // MUST never overflow, can be caused by data corruption, TODO
786 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 888 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
787 abort (); // MUST never overflow, can be caused by data corruption, TODO 889 reset ();
890 return;
788 } 891 }
789 892
790 while (vpn_packet *pkt = rcvdq.get ()) 893 while (vpn_packet *pkt = rcvdq.get ())
791 { 894 {
792 sockinfo si; 895 sockinfo si;
793 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; 896 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
794 897
795 vpn->recv_vpn_packet (pkt, si); 898 vpn->recv_vpn_packet (pkt, si);
796
797 delete pkt; 899 delete pkt;
798 } 900 }
799 901
800 // check for further packets 902 // check for further packets
801 goto redo; 903 goto redo;
… …
844 { 946 {
845 // correct class, domain: parse 947 // correct class, domain: parse
846 int client, seqno; 948 int client, seqno;
847 decode_header (qname, client, seqno); 949 decode_header (qname, client, seqno);
848 950
849 u8 data[MAXSIZE];
850 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
851
852 if (0 < client && client <= conns.size ()) 951 if (0 < client && client <= conns.size ())
853 { 952 {
854 connection *c = conns [client - 1]; 953 connection *c = conns [client - 1];
855 dns_connection *dns = c->dns; 954 dns_connection *dns = c->dns;
856 dns_rcv *rcv; 955 dns_rcv *rcv;
857 956
858 if (dns) 957 if (dns)
859 { 958 {
959 u8 data[MAXSIZE];
960 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
961
860 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 (); )
861 if (SEQNO_EQ ((*i)->seqno, seqno)) 963 if (SEQNO_EQ ((*i)->seqno, seqno))
862 { 964 {
863 // already seen that request: simply reply with the cached reply 965 // already seen that request: simply reply with the cached reply
864 dns_rcv *r = *i; 966 dns_rcv *r = *i;
… …
965 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
966 pkt [offs++] = 0; pkt [offs++] = 0; 1068 pkt [offs++] = 0; pkt [offs++] = 0;
967 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1069 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
968 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1070 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
969 1071
970 slog (L_INFO, _("DNS: client %d connects"), client);
971
972 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;
973 pkt [offs++] = CMD_IP_REJ; 1073 pkt [offs++] = CMD_IP_REJ;
974 1074
975 if (0 < client && client <= conns.size ()) 1075 if (0 < client && client <= conns.size ())
976 { 1076 {
977 connection *c = conns [client - 1]; 1077 connection *c = conns [client - 1];
978 1078
979 if (cfg.valid ()) 1079 if (cfg.valid ())
980 { 1080 {
981 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));
982 1086
983 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
984 c->dns = new dns_connection (c); 1092 c->dns = new dns_connection (c);
985 c->dns->cfg = cfg; 1093 c->dns->cfg = cfg;
1094 c->dns->set_cfg ();
986 } 1095 }
987 } 1096 }
988 } 1097 }
989 } 1098 }
990 1099
… …
1009 { 1118 {
1010 dns_connection *dns = (*i)->dns; 1119 dns_connection *dns = (*i)->dns;
1011 connection *c = dns->c; 1120 connection *c = dns->c;
1012 int seqno = (*i)->seqno; 1121 int seqno = (*i)->seqno;
1013 u8 data[MAXSIZE], *datap = data; 1122 u8 data[MAXSIZE], *datap = data;
1123 //printf ("rcv pkt %x\n", seqno);//D
1014 1124
1015 if ((*i)->retry) 1125 if ((*i)->retry)
1016 { 1126 {
1017 dns->send_interval *= 1.01; 1127 dns->send_interval *= 1.01;
1018 if (dns->send_interval > MAX_SEND_INTERVAL) 1128 if (dns->send_interval > MAX_SEND_INTERVAL)
… …
1023#if 0 1133#if 0
1024 dns->send_interval *= 0.999; 1134 dns->send_interval *= 0.999;
1025#endif 1135#endif
1026 // the latency surely puts an upper bound on 1136 // the latency surely puts an upper bound on
1027 // the minimum send interval 1137 // the minimum send interval
1028 double latency = NOW - (*i)->sent; 1138 double latency = ev_now () - (*i)->sent;
1029 1139
1030 if (latency < dns->min_latency) 1140 if (latency < dns->min_latency)
1031 dns->min_latency = latency; 1141 dns->min_latency = latency;
1032 1142
1033 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) 1143 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
… …
1060 ttl |= pkt [offs++] << 16; 1170 ttl |= pkt [offs++] << 16;
1061 ttl |= pkt [offs++] << 8; 1171 ttl |= pkt [offs++] << 8;
1062 ttl |= pkt [offs++]; 1172 ttl |= pkt [offs++];
1063 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1173 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1064 1174
1065 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1175 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1066 { 1176 {
1067 if (rdlen <= MAXSIZE - offs) 1177 if (rdlen <= MAXSIZE - offs)
1068 { 1178 {
1069 // decode bytes, finally 1179 // decode bytes, finally
1070 1180
… …
1096 { 1206 {
1097 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1207 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1098 1208
1099 if (ip [3] == CMD_IP_RST) 1209 if (ip [3] == CMD_IP_RST)
1100 { 1210 {
1101 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1211 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1102 1212
1103 delete dns; c->dns = 0; 1213 dns->reset ();
1104
1105 return; 1214 return;
1106 } 1215 }
1107 else if (ip [3] == CMD_IP_SYN) 1216 else if (ip [3] == CMD_IP_SYN)
1108 { 1217 {
1109 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1218 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1110 dns->established = true; 1219 dns->established = true;
1111 } 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 }
1112 else if (ip [3] == CMD_IP_REJ) 1236 else if (ip [3] == CMD_IP_REJ)
1113 { 1237 {
1114 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1238 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1115 abort (); 1239 dns->tw.start (60.);
1116 } 1240 }
1117 else 1241 else
1242 {
1118 slog (L_INFO, _("DNS: 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 }
1119 } 1246 }
1120 else 1247 else
1121 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1248 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1122 ip [0], ip [1], ip [2], ip [3]); 1249 ip [0], ip [1], ip [2], ip [3]);
1123 1250
… …
1147 break; 1274 break;
1148 } 1275 }
1149} 1276}
1150 1277
1151void 1278void
1152vpn::dnsv4_ev (io_watcher &w, short revents) 1279vpn::dnsv4_ev (ev::io &w, int revents)
1153{ 1280{
1154 if (revents & EVENT_READ) 1281 if (revents & EV_READ)
1155 { 1282 {
1156 dns_packet *pkt = new dns_packet; 1283 dns_packet *pkt = new dns_packet;
1157 struct sockaddr_in sa; 1284 struct sockaddr_in sa;
1158 socklen_t sa_len = sizeof (sa); 1285 socklen_t sa_len = sizeof (sa);
1159 1286
… …
1185 1312
1186 if (!c->dns) 1313 if (!c->dns)
1187 c->dns = new dns_connection (c); 1314 c->dns = new dns_connection (c);
1188 1315
1189 if (c->dns->snddq.put (pkt)) 1316 if (c->dns->snddq.put (pkt))
1317 {
1318 min_it (c->dns->poll_interval, 0.25);
1190 c->dns->tw.trigger (); 1319 c->dns->tw ();
1320 }
1191 1321
1192 // always return true even if the buffer overflows 1322 // always return true even if the buffer overflows
1193 return true; 1323 return true;
1194} 1324}
1195 1325
1196void 1326void
1197connection::dnsv4_reset_connection () 1327dns_connection::time_cb (ev::timer &w, int revents)
1198{
1199 //delete dns; dns = 0; //TODO
1200}
1201
1202#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1203
1204void
1205dns_connection::time_cb (time_watcher &w)
1206{ 1328{
1207 // servers have to be polled 1329 // servers have to be polled
1208 if (THISNODE->dns_port) 1330 if (THISNODE->dns_port)
1209 return; 1331 return;
1210 1332
1211 // check for timeouts and (re)transmit 1333 // check for timeouts and (re)transmit
1212 tstamp next = NOW + poll_interval; 1334 tstamp next = 86400 * 365;
1213 dns_snd *send = 0; 1335 dns_snd *send = 0;
1214 1336
1215 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1337 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1216 i != vpn->dns_sndpq.end (); 1338 i != vpn->dns_sndpq.end ();
1217 ++i) 1339 ++i)
1218 { 1340 {
1219 dns_snd *r = *i; 1341 dns_snd *r = *i;
1220 1342
1221 if (r->timeout <= NOW) 1343 if (r->timeout <= ev_now ())
1222 { 1344 {
1223 if (!send) 1345 if (!send)
1224 { 1346 {
1225 send = r; 1347 send = r;
1226 1348
1227 r->retry++; 1349 r->retry++;
1228 r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor); 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
1229 1352
1230 // the following code changes the query section a bit, forcing 1353 // the following code changes the query section a bit, forcing
1231 // the forwarder to generate a new request 1354 // the forwarder to generate a new request
1232 if (r->stdhdr) 1355 if (r->stdhdr)
1233 {
1234 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1235 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1356 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1236 }
1237 } 1357 }
1238 } 1358 }
1239 else 1359 else
1240 NEXT (r->timeout); 1360 min_it (next, r->timeout - ev_now ());
1241 } 1361 }
1242 1362
1243 if (!send) 1363 if (!send)
1244 { 1364 {
1245 // generate a new packet, if wise 1365 // generate a new packet, if wise
… …
1249 if (vpn->dns_sndpq.empty ()) 1369 if (vpn->dns_sndpq.empty ())
1250 { 1370 {
1251 send = new dns_snd (this); 1371 send = new dns_snd (this);
1252 1372
1253 cfg.reset (THISNODE->id); 1373 cfg.reset (THISNODE->id);
1374 set_cfg ();
1254 send->gen_syn_req (); 1375 send->gen_syn_req ();
1255 } 1376 }
1256 } 1377 }
1257 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1378 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1258 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1379 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1259 { 1380 {
1260 if (last_sent + send_interval <= NOW) 1381 if (last_sent + send_interval <= ev_now ())
1261 { 1382 {
1262 //printf ("sending data request etc.\n"); //D 1383 //printf ("sending data request etc.\n"); //D
1263 if (!snddq.empty () || last_received + 1. > NOW) 1384 if (!snddq.empty ())
1264 {
1265 poll_interval = send_interval;
1266 NEXT (NOW + send_interval); 1385 min_it (next, send_interval);
1267 }
1268 1386
1269 send = new dns_snd (this); 1387 send = new dns_snd (this);
1270 send->gen_stream_req (sndseq, snddq); 1388 send->gen_stream_req (sndseq, snddq);
1271 send->timeout = NOW + min_latency * conf.dns_timeout_factor; 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
1272 1391
1273 sndseq = (sndseq + 1) & SEQNO_MASK; 1392 sndseq = (sndseq + 1) & SEQNO_MASK;
1274 } 1393 }
1275 else 1394 else
1276 NEXT (last_sent + send_interval); 1395 min_it (next, last_sent + send_interval - ev_now ());
1277 } 1396 }
1278 1397
1279 if (send) 1398 if (send)
1280 vpn->dns_sndpq.push_back (send); 1399 vpn->dns_sndpq.push_back (send);
1281 } 1400 }
1282 1401
1283 if (send) 1402 if (send)
1284 { 1403 {
1285 last_sent = NOW; 1404 last_sent = ev_now ();
1286 sendto (vpn->dnsv4_fd, 1405 sendto (vpn->dnsv4_fd,
1287 send->pkt->at (0), send->pkt->len, 0, 1406 send->pkt->at (0), send->pkt->len, 0,
1288 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1407 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1289 } 1408 }
1290 1409
1410 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1411
1291 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1412 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1292 poll_interval, send_interval, next - NOW, 1413 poll_interval, send_interval, next - ev_now (),
1293 vpn->dns_sndpq.size (), snddq.size (), 1414 vpn->dns_sndpq.size (), snddq.size (),
1294 rcvpq.size ()); 1415 rcvpq.size ());
1295 1416
1296 // TODO: no idea when this happens, but when next < NOW, we have a problem
1297 // doesn't seem to happen anymore
1298 if (next < NOW + 0.001)
1299 next = NOW + 0.1;
1300
1301 w.start (next); 1417 w.start (next);
1302} 1418}
1303 1419
1304#endif 1420#endif
1305 1421

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