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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 1.52 by root, Sun Mar 6 21:01:37 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 240 // 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
… …
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;
… …
410 448
411struct dns_cfg 449struct dns_cfg
412{ 450{
413 static int next_uid; 451 static int next_uid;
414 452
415 u8 id1, id2, id3, id4; 453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
416 456
417 u8 version; 457 u8 version;
418 u8 flags; 458 u8 flags;
419 u8 rrtype; 459 u16 max_size;
460
461 u8 id1, id2, id3, id4;
462
463 u16 client;
420 u8 def_ttl; 464 u8 def_ttl;
465 u8 r0;
421 466
422 u16 client; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
423 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
424 471
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; 472 u8 r1, r2, r3, r4;
434 473
435 void reset (int clientid); 474 void reset (int clientid);
436 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
437}; 477};
438 478
439int dns_cfg::next_uid; 479int dns_cfg::next_uid;
440 480
481void
441void dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
442{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
443 id1 = 'G'; 485 id1 = 'G';
444 id2 = 'V'; 486 id2 = 'V';
445 id3 = 'P'; 487 id3 = 'P';
446 id4 = 'E'; 488 id4 = 'E';
447 489
448 version = 1; 490 version = 2;
449 491
450 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
451 flags = 0; 493 flags = 0;
452 def_ttl = 0; 494 def_ttl = 0;
453 seq_cdc = 26; 495 syn_cdc = 26;
454 req_cdc = 62; 496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
455 rep_cdc = 0; 498 rep_cdc = 0;
456 max_size = htons (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
457 client = htons (clientid); 500 client = htons (clientid);
458 uid = next_uid++; 501 uid = ++next_uid;
459 delay = 0;
460 502
461 r3 = r4 = 0; 503 r0 = r1 = r2 = r3 = r4 = 0;
462 r4 = r5 = r6 = r7 = 0;
463}
464 504
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
465bool dns_cfg::valid () 526dns_cfg::valid ()
466{ 527{
528 // although the protocol itself allows for some configurability,
529 // only the following encoding/decoding settings are implemented.
467 return id1 == 'G' 530 return id1 == 'G'
468 && id2 == 'V' 531 && id2 == 'V'
469 && id3 == 'P' 532 && id3 == 'P'
470 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
471 && seq_cdc == 26 535 && syn_cdc == 26
472 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
473 && rep_cdc == 0 538 && rep_cdc == 0
474 && version == 1; 539 && chksum == get_chksum ();
475} 540}
476 541
477struct dns_packet : net_packet 542struct dns_packet : net_packet
478{ 543{
479 u16 id; 544 u16 id;
… …
483 u8 data [MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
484 549
485 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
486}; 551};
487 552
553int
488int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
489{ 555{
490 char *orig = data; 556 char *orig = data;
491 557
492 memset (data, 0, size); 558 memset (data, 0, size);
493 559
… …
519 return data - orig; 585 return data - orig;
520} 586}
521 587
522///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
523 589
590static
591u16 next_id ()
592{
524static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
525 594
526static u16 next_id ()
527{
528 if (!dns_id) 595 if (!dns_id)
529 dns_id = time (0); 596 dns_id = time (0);
530 597
531 // the simplest lsfr with periodicity 65535 i could find 598 // the simplest lsfr with periodicity 65535 i could find
532 dns_id = (dns_id << 1) 599 dns_id = (dns_id << 1)
… …
547 struct vpn *vpn; 614 struct vpn *vpn;
548 615
549 dns_cfg cfg; 616 dns_cfg cfg;
550 617
551 bool established; 618 bool established;
619 const basecoder *cdc;
552 620
553 tstamp last_received; 621 tstamp last_received;
554 tstamp last_sent; 622 tstamp last_sent;
555 double min_latency; 623 double min_latency;
556 double poll_interval, send_interval; 624 double poll_interval, send_interval;
… …
558 vector<dns_rcv *> rcvpq; 626 vector<dns_rcv *> rcvpq;
559 627
560 byte_stream rcvdq; int rcvseq; int repseq; 628 byte_stream rcvdq; int rcvseq; int repseq;
561 byte_stream snddq; int sndseq; 629 byte_stream snddq; int sndseq;
562 630
563 void time_cb (time_watcher &w); time_watcher tw; 631 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
564 void receive_rep (dns_rcv *r); 632 void receive_rep (dns_rcv *r);
633
634 void reset (); // quite like tcp RST
635 void set_cfg (); // to be called after any cfg changes
565 636
566 dns_connection (connection *c); 637 dns_connection (connection *c);
567 ~dns_connection (); 638 ~dns_connection ();
568}; 639};
569 640
… …
587: dns (dns) 658: dns (dns)
588{ 659{
589 timeout = 0; 660 timeout = 0;
590 retry = 0; 661 retry = 0;
591 seqno = 0; 662 seqno = 0;
592 sent = NOW; 663 sent = ev_now ();
593 stdhdr = false; 664 stdhdr = false;
594 665
595 pkt = new dns_packet; 666 pkt = new dns_packet;
596 667
597 pkt->id = next_id (); 668 pkt->id = next_id ();
… …
600dns_snd::~dns_snd () 671dns_snd::~dns_snd ()
601{ 672{
602 delete pkt; 673 delete pkt;
603} 674}
604 675
676static void
605static void append_domain (dns_packet &pkt, int &offs, const char *domain) 677append_domain (dns_packet &pkt, int &offs, const char *domain)
606{ 678{
607 // add tunnel domain 679 // add tunnel domain
608 for (;;) 680 for (;;)
609 { 681 {
610 const char *end = strchr (domain, '.'); 682 const char *end = strchr (domain, '.');
… …
623 695
624 domain = end + 1; 696 domain = end + 1;
625 } 697 }
626} 698}
627 699
700void
628void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 701dns_snd::gen_stream_req (int seqno, byte_stream &stream)
629{ 702{
630 stdhdr = true; 703 stdhdr = true;
631 this->seqno = seqno; 704 this->seqno = seqno;
632 705
633 timeout = NOW + INITIAL_TIMEOUT; 706 timeout = ev_now () + INITIAL_TIMEOUT;
634 707
635 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 708 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
636 pkt->qdcount = htons (1); 709 pkt->qdcount = htons (1);
637 710
638 int offs = 6*2; 711 int offs = 6*2;
… …
641 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 714 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
642 715
643 char enc[256], *encp = enc; 716 char enc[256], *encp = enc;
644 encode_header (enc, THISNODE->id, seqno); 717 encode_header (enc, THISNODE->id, seqno);
645 718
646 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 719 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
647 720
648 if (datalen > stream.size ()) 721 if (datalen > stream.size ())
649 datalen = stream.size (); 722 datalen = stream.size ();
650 723
651 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 724 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
652 stream.remove (datalen); 725 stream.remove (datalen);
653 726
654 while (enclen) 727 while (enclen)
655 { 728 {
656 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 729 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
671 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 744 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
672 745
673 pkt->len = offs; 746 pkt->len = offs;
674} 747}
675 748
749void
676void dns_snd::gen_syn_req () 750dns_snd::gen_syn_req ()
677{ 751{
678 timeout = NOW + INITIAL_SYN_TIMEOUT; 752 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
679 753
680 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 754 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
681 pkt->qdcount = htons (1); 755 pkt->qdcount = htons (1);
682 756
683 int offs = 6 * 2; 757 int offs = 6 * 2;
… …
723 797
724dns_connection::dns_connection (connection *c) 798dns_connection::dns_connection (connection *c)
725: c (c) 799: c (c)
726, rcvdq (MAX_BACKLOG * 2) 800, rcvdq (MAX_BACKLOG * 2)
727, snddq (MAX_BACKLOG) 801, snddq (MAX_BACKLOG)
728, tw (this, &dns_connection::time_cb)
729{ 802{
803 tw.set<dns_connection, &dns_connection::time_cb> (this);
804
730 vpn = c->vpn; 805 vpn = c->vpn;
731 806
807 reset ();
808}
809
810dns_connection::~dns_connection ()
811{
812 reset ();
813}
814
815void
816dns_connection::reset ()
817{
818 while (!rcvpq.empty ())
819 {
820 delete rcvpq.back ();
821 rcvpq.pop_back ();
822 }
823
824 for (int i = vpn->dns_sndpq.size (); i--; )
825 if (vpn->dns_sndpq [i]->dns == this)
826 {
827 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
828 vpn->dns_sndpq.pop_back ();
829 }
830
732 established = false; 831 established = false;
733 832
734 rcvseq = repseq = sndseq = 0; 833 rcvseq = repseq = sndseq = 0;
735 834
736 last_sent = last_received = 0; 835 last_sent = 0;
737 poll_interval = 0.5; // starting here 836 poll_interval = 0.5; // starting here
738 send_interval = 0.5; // starting rate 837 send_interval = 0.5; // starting rate
739 min_latency = INITIAL_TIMEOUT; 838 min_latency = INITIAL_TIMEOUT;
740} 839}
741 840
742dns_connection::~dns_connection () 841void
842dns_connection::set_cfg ()
743{ 843{
744 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 844 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
745 i != rcvpq.end ();
746 ++i)
747 delete *i;
748} 845}
749 846
847void
750void dns_connection::receive_rep (dns_rcv *r) 848dns_connection::receive_rep (dns_rcv *r)
751{ 849{
752 if (r->datalen) 850 if (r->datalen)
753 { 851 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 852 else
760 { 853 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 }
766 854
767 rcvpq.push_back (r); 855 rcvpq.push_back (r);
768 856
769 redo: 857 redo:
770 858
771 // find next packet 859 // find next packet
772 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 860 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
773 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 861 if (SEQNO_EQ (rcvseq, (*i)->seqno))
774 { 862 {
863 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
775 // enter the packet into our input stream 864 // enter the packet into our input stream
776 r = *i; 865 r = *i;
777 866
778 // remove the oldest packet, look forward, as it's oldest first 867 // remove the oldest packet, look forward, as it's oldest first
779 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 868 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
780 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 869 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
781 { 870 {
871 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
782 delete *j; 872 delete *j;
783 rcvpq.erase (j); 873 rcvpq.erase (j);
784 break; 874 break;
785 } 875 }
786 876
787 rcvseq = (rcvseq + 1) & SEQNO_MASK; 877 rcvseq = (rcvseq + 1) & SEQNO_MASK;
788 878
789 if (!rcvdq.put (r->data, r->datalen)) 879 if (!rcvdq.put (r->data, r->datalen))
790 { 880 {
881 // MUST never overflow, can be caused by data corruption, TODO
791 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 882 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
792 abort (); // MUST never overflow, can be caused by data corruption, TODO 883 reset ();
884 return;
793 } 885 }
794 886
795 while (vpn_packet *pkt = rcvdq.get ()) 887 while (vpn_packet *pkt = rcvdq.get ())
796 { 888 {
797 sockinfo si; 889 sockinfo si;
798 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; 890 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
799 891
800 vpn->recv_vpn_packet (pkt, si); 892 vpn->recv_vpn_packet (pkt, si);
801
802 delete pkt; 893 delete pkt;
803 } 894 }
804 895
805 // check for further packets 896 // check for further packets
806 goto redo; 897 goto redo;
… …
849 { 940 {
850 // correct class, domain: parse 941 // correct class, domain: parse
851 int client, seqno; 942 int client, seqno;
852 decode_header (qname, client, seqno); 943 decode_header (qname, client, seqno);
853 944
854 u8 data[MAXSIZE];
855 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
856
857 if (0 < client && client <= conns.size ()) 945 if (0 < client && client <= conns.size ())
858 { 946 {
859 connection *c = conns [client - 1]; 947 connection *c = conns [client - 1];
860 dns_connection *dns = c->dns; 948 dns_connection *dns = c->dns;
861 dns_rcv *rcv; 949 dns_rcv *rcv;
862 950
863 if (dns) 951 if (dns)
864 { 952 {
953 u8 data[MAXSIZE];
954 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
955
865 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 956 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
866 if (SEQNO_EQ ((*i)->seqno, seqno)) 957 if (SEQNO_EQ ((*i)->seqno, seqno))
867 { 958 {
868 // already seen that request: simply reply with the cached reply 959 // already seen that request: simply reply with the cached reply
869 dns_rcv *r = *i; 960 dns_rcv *r = *i;
… …
970 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1061 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
971 pkt [offs++] = 0; pkt [offs++] = 0; 1062 pkt [offs++] = 0; pkt [offs++] = 0;
972 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1063 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
973 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1064 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
974 1065
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; 1066 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
978 pkt [offs++] = CMD_IP_REJ; 1067 pkt [offs++] = CMD_IP_REJ;
979 1068
980 if (0 < client && client <= conns.size ()) 1069 if (0 < client && client <= conns.size ())
981 { 1070 {
982 connection *c = conns [client - 1]; 1071 connection *c = conns [client - 1];
983 1072
984 if (cfg.valid ()) 1073 if (cfg.valid ())
985 { 1074 {
986 pkt [offs - 1] = CMD_IP_SYN; 1075 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1076
1077 // check for any encoding mismatches - hints at a case problem
1078 char qname2 [MAX_ENC_LEN];
1079 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
987 1080
988 delete c->dns; 1081 delete c->dns;
1082
1083 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1084 ? CMD_IP_CSE : CMD_IP_SYN;
1085
989 c->dns = new dns_connection (c); 1086 c->dns = new dns_connection (c);
990 c->dns->cfg = cfg; 1087 c->dns->cfg = cfg;
1088 c->dns->set_cfg ();
991 } 1089 }
992 } 1090 }
993 } 1091 }
994 } 1092 }
995 1093
… …
1014 { 1112 {
1015 dns_connection *dns = (*i)->dns; 1113 dns_connection *dns = (*i)->dns;
1016 connection *c = dns->c; 1114 connection *c = dns->c;
1017 int seqno = (*i)->seqno; 1115 int seqno = (*i)->seqno;
1018 u8 data[MAXSIZE], *datap = data; 1116 u8 data[MAXSIZE], *datap = data;
1117 //printf ("rcv pkt %x\n", seqno);//D
1019 1118
1020 if ((*i)->retry) 1119 if ((*i)->retry)
1021 { 1120 {
1022 dns->send_interval *= 1.01; 1121 dns->send_interval *= 1.01;
1023 if (dns->send_interval > MAX_SEND_INTERVAL) 1122 if (dns->send_interval > MAX_SEND_INTERVAL)
… …
1028#if 0 1127#if 0
1029 dns->send_interval *= 0.999; 1128 dns->send_interval *= 0.999;
1030#endif 1129#endif
1031 // the latency surely puts an upper bound on 1130 // the latency surely puts an upper bound on
1032 // the minimum send interval 1131 // the minimum send interval
1033 double latency = NOW - (*i)->sent; 1132 double latency = ev_now () - (*i)->sent;
1034 1133
1035 if (latency < dns->min_latency) 1134 if (latency < dns->min_latency)
1036 dns->min_latency = latency; 1135 dns->min_latency = latency;
1037 1136
1038 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR) 1137 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1039 dns->send_interval = dns->min_latency * LATENCY_FACTOR; 1138 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1040 1139
1041 if (dns->send_interval < MIN_SEND_INTERVAL) 1140 if (dns->send_interval < conf.dns_send_interval)
1042 dns->send_interval = MIN_SEND_INTERVAL; 1141 dns->send_interval = conf.dns_send_interval;
1043 } 1142 }
1044 1143
1045 delete *i; 1144 delete *i;
1046 dns_sndpq.erase (i); 1145 dns_sndpq.erase (i);
1047 1146
… …
1065 ttl |= pkt [offs++] << 16; 1164 ttl |= pkt [offs++] << 16;
1066 ttl |= pkt [offs++] << 8; 1165 ttl |= pkt [offs++] << 8;
1067 ttl |= pkt [offs++]; 1166 ttl |= pkt [offs++];
1068 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1167 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1069 1168
1070 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1169 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1071 { 1170 {
1072 if (rdlen <= MAXSIZE - offs) 1171 if (rdlen <= MAXSIZE - offs)
1073 { 1172 {
1074 // decode bytes, finally 1173 // decode bytes, finally
1075 1174
… …
1101 { 1200 {
1102 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1201 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1103 1202
1104 if (ip [3] == CMD_IP_RST) 1203 if (ip [3] == CMD_IP_RST)
1105 { 1204 {
1106 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1205 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1107 1206
1108 delete dns; c->dns = 0; 1207 dns->reset ();
1109
1110 return; 1208 return;
1111 } 1209 }
1112 else if (ip [3] == CMD_IP_SYN) 1210 else if (ip [3] == CMD_IP_SYN)
1113 { 1211 {
1114 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1212 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1115 dns->established = true; 1213 dns->established = true;
1116 } 1214 }
1215 else if (ip [3] == CMD_IP_CSE)
1216 {
1217 if (conf.dns_case_preserving)
1218 {
1219 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1220 conf.dns_case_preserving = false;
1221 dns->reset ();
1222 return;
1223 }
1224 else
1225 {
1226 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1227 dns->established = true;
1228 }
1229 }
1117 else if (ip [3] == CMD_IP_REJ) 1230 else if (ip [3] == CMD_IP_REJ)
1118 { 1231 {
1119 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1232 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1120 abort (); 1233 dns->tw.start (60.);
1121 } 1234 }
1122 else 1235 else
1236 {
1123 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1237 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1238 dns->tw.start (60.);
1239 }
1124 } 1240 }
1125 else 1241 else
1126 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1242 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1127 ip [0], ip [1], ip [2], ip [3]); 1243 ip [0], ip [1], ip [2], ip [3]);
1128 1244
… …
1152 break; 1268 break;
1153 } 1269 }
1154} 1270}
1155 1271
1156void 1272void
1157vpn::dnsv4_ev (io_watcher &w, short revents) 1273vpn::dnsv4_ev (ev::io &w, int revents)
1158{ 1274{
1159 if (revents & EVENT_READ) 1275 if (revents & EV_READ)
1160 { 1276 {
1161 dns_packet *pkt = new dns_packet; 1277 dns_packet *pkt = new dns_packet;
1162 struct sockaddr_in sa; 1278 struct sockaddr_in sa;
1163 socklen_t sa_len = sizeof (sa); 1279 socklen_t sa_len = sizeof (sa);
1164 1280
… …
1190 1306
1191 if (!c->dns) 1307 if (!c->dns)
1192 c->dns = new dns_connection (c); 1308 c->dns = new dns_connection (c);
1193 1309
1194 if (c->dns->snddq.put (pkt)) 1310 if (c->dns->snddq.put (pkt))
1311 {
1312 min_it (c->dns->poll_interval, 0.25);
1195 c->dns->tw.trigger (); 1313 c->dns->tw ();
1314 }
1196 1315
1197 // always return true even if the buffer overflows 1316 // always return true even if the buffer overflows
1198 return true; 1317 return true;
1199} 1318}
1200 1319
1201void 1320void
1202connection::dnsv4_reset_connection () 1321dns_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{ 1322{
1212 // servers have to be polled 1323 // servers have to be polled
1213 if (THISNODE->dns_port) 1324 if (THISNODE->dns_port)
1214 return; 1325 return;
1215 1326
1216 // check for timeouts and (re)transmit 1327 // check for timeouts and (re)transmit
1217 tstamp next = NOW + poll_interval; 1328 tstamp next = 86400 * 365;
1218 dns_snd *send = 0; 1329 dns_snd *send = 0;
1219 1330
1220 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1331 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1221 i != vpn->dns_sndpq.end (); 1332 i != vpn->dns_sndpq.end ();
1222 ++i) 1333 ++i)
1223 { 1334 {
1224 dns_snd *r = *i; 1335 dns_snd *r = *i;
1225 1336
1226 if (r->timeout <= NOW) 1337 if (r->timeout <= ev_now ())
1227 { 1338 {
1228 if (!send) 1339 if (!send)
1229 { 1340 {
1230 send = r; 1341 send = r;
1231 1342
1232 r->retry++; 1343 r->retry++;
1233 r->timeout = NOW + (r->retry * min_latency * TIMEOUT_FACTOR); 1344 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1345 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1234 1346
1235 // the following code changes the query section a bit, forcing 1347 // the following code changes the query section a bit, forcing
1236 // the forwarder to generate a new request 1348 // the forwarder to generate a new request
1237 if (r->stdhdr) 1349 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); 1350 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1241 }
1242 } 1351 }
1243 } 1352 }
1244 else 1353 else
1245 NEXT (r->timeout); 1354 min_it (next, r->timeout - ev_now ());
1246 } 1355 }
1247 1356
1248 if (!send) 1357 if (!send)
1249 { 1358 {
1250 // generate a new packet, if wise 1359 // generate a new packet, if wise
… …
1254 if (vpn->dns_sndpq.empty ()) 1363 if (vpn->dns_sndpq.empty ())
1255 { 1364 {
1256 send = new dns_snd (this); 1365 send = new dns_snd (this);
1257 1366
1258 cfg.reset (THISNODE->id); 1367 cfg.reset (THISNODE->id);
1368 set_cfg ();
1259 send->gen_syn_req (); 1369 send->gen_syn_req ();
1260 } 1370 }
1261 } 1371 }
1262 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1372 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1263 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1373 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1264 { 1374 {
1265 if (last_sent + send_interval <= NOW) 1375 if (last_sent + send_interval <= ev_now ())
1266 { 1376 {
1267 //printf ("sending data request etc.\n"); //D 1377 //printf ("sending data request etc.\n"); //D
1268 if (!snddq.empty () || last_received + 1. > NOW) 1378 if (!snddq.empty ())
1269 {
1270 poll_interval = send_interval;
1271 NEXT (NOW + send_interval); 1379 min_it (next, send_interval);
1272 }
1273 1380
1274 send = new dns_snd (this); 1381 send = new dns_snd (this);
1275 send->gen_stream_req (sndseq, snddq); 1382 send->gen_stream_req (sndseq, snddq);
1276 send->timeout = NOW + min_latency * TIMEOUT_FACTOR; 1383 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1384 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1277 1385
1278 sndseq = (sndseq + 1) & SEQNO_MASK; 1386 sndseq = (sndseq + 1) & SEQNO_MASK;
1279 } 1387 }
1280 else 1388 else
1281 NEXT (last_sent + send_interval); 1389 min_it (next, last_sent + send_interval - ev_now ());
1282 } 1390 }
1283 1391
1284 if (send) 1392 if (send)
1285 vpn->dns_sndpq.push_back (send); 1393 vpn->dns_sndpq.push_back (send);
1286 } 1394 }
1287 1395
1288 if (send) 1396 if (send)
1289 { 1397 {
1290 last_sent = NOW; 1398 last_sent = ev_now ();
1291 sendto (vpn->dnsv4_fd, 1399 sendto (vpn->dnsv4_fd,
1292 send->pkt->at (0), send->pkt->len, 0, 1400 send->pkt->at (0), send->pkt->len, 0,
1293 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1401 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1294 } 1402 }
1295 1403
1404 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1405
1296 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1406 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1297 poll_interval, send_interval, next - NOW, 1407 poll_interval, send_interval, next - ev_now (),
1298 vpn->dns_sndpq.size (), snddq.size (), 1408 vpn->dns_sndpq.size (), snddq.size (),
1299 rcvpq.size ()); 1409 rcvpq.size ());
1300 1410
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); 1411 w.start (next);
1306} 1412}
1307 1413
1308#endif 1414#endif
1309 1415

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