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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.39 by pcg, Tue Apr 26 00:55:56 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. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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*/
21 31
22// TODO: EDNS0 option to increase dns mtu? 32// TODO: EDNS0 option to increase dns mtu?
23// TODO: re-write dns packet parsing/creation using a safe mem-buffer 33// TODO: re-write dns packet parsing/creation using a safe mem-buffer
24// to ensure no buffer overflows or similar problems. 34// to ensure no buffer overflows or similar problems.
… …
42#include <unistd.h> 52#include <unistd.h>
43#include <fcntl.h> 53#include <fcntl.h>
44 54
45#include <map> 55#include <map>
46 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
47#include <gmp.h> 58#include <gmp.h>
48 59
49#include "netcompat.h" 60#include "netcompat.h"
50 61
51#include "vpn.h" 62#include "vpn.h"
52 63
64#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received
53#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
54#define ACTIVITY_INTERVAL 5.
55 66
56#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
57#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
58 69
59#define MAX_SEND_INTERVAL 2. // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
60 71
61#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
62#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
63 74
64#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
… …
72#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
73 84
74#define RR_TYPE_A 1 85#define RR_TYPE_A 1
75#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
76#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
77#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
78 90
79#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
80 92
81#define CMD_IP_1 207 93#define CMD_IP_1 207
82#define CMD_IP_2 46 94#define CMD_IP_2 46
83#define CMD_IP_3 236 95#define CMD_IP_3 236
84#define CMD_IP_RST 29 96
85#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
86#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}
87 113
88// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
89struct charmap 115struct charmap
90{ 116{
91 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
105 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
106 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
107 133
108 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
109 { 135 {
136 char c = cmap [size];
137
110 enc [size] = cmap [size]; 138 enc [size] = c;
111 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;
112 } 144 }
113 145
114 assert (size < 256); 146 assert (size < 256);
115} 147}
116 148
… …
123{ 155{
124 charmap cmap; 156 charmap cmap;
125 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
126 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
127 159
128 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
129 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
130 162
131 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
132 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
133 165
134 basecoder (const char *cmap); 166 basecoder (const char *cmap);
135}; 167};
136 168
137basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
156 enc_len [len] = n; 188 enc_len [len] = n;
157 dec_len [n] = len; 189 dec_len [n] = len;
158 } 190 }
159} 191}
160 192
193unsigned int
161unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
162{ 195{
163 return enc_len [len]; 196 return enc_len [len];
164} 197}
165 198
199unsigned int
166unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
167{ 201{
168 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
169 --len; 203 --len;
170 204
171 return dec_len [len]; 205 return dec_len [len];
172} 206}
173 207
208unsigned int
174unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
175{ 210{
176 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
177 return 0; 212 return 0;
178 213
179 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
198 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
199 234
200 return elen; 235 return elen;
201} 236}
202 237
238unsigned int
203unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
204{ 240{
205 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
206 return 0; 242 return 0;
207 243
208 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
257 } 293 }
258 abort (); 294 abort ();
259} 295}
260#endif 296#endif
261 297
262//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
263//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
264static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
265//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
266static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
267 301
268///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
269 303
270#define HDRSIZE 6 304#define HDRSIZE 5
271 305
306inline void
272inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
273{ 308{
309 assert (clientid < 256);
310
274 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
275 312
276 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
277 clientid, 316 clientid,
278 (seqno >> 8) | (retry << 6),
279 seqno,
280 }; 317 };
281 318
282 assert (clientid < 256);
283
284 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
285} 320}
286 321
322inline void
287inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
288{ 324{
289 u8 hdr[3]; 325 u8 hdr[3];
290 326
291 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
292 328
293 clientid = hdr[0]; 329 clientid = hdr[2];
294 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
295} 331}
296 332
297///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
298 334
299struct byte_stream 335struct byte_stream
… …
325byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
326{ 362{
327 delete data; 363 delete data;
328} 364}
329 365
366void
330void byte_stream::remove (int count) 367byte_stream::remove (int count)
331{ 368{
332 if (count > fill) 369 if (count > fill)
333 assert (count <= fill); 370 assert (count <= fill);
334 371
335 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
336} 373}
337 374
375bool
338bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
339{ 377{
340 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
341 return false; 379 return false;
342 380
343 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
344 382
345 return true; 383 return true;
346} 384}
347 385
386bool
348bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
349{ 388{
350 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
351 return false; 390 return false;
352 391
353 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
… …
409 448
410struct dns_cfg 449struct dns_cfg
411{ 450{
412 static int next_uid; 451 static int next_uid;
413 452
414 u8 id1, id2, id3, id4; 453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
415 456
416 u8 version; 457 u8 version;
417 u8 flags; 458 u8 flags;
418 u8 rrtype; 459 u16 max_size;
460
461 u8 id1, id2, id3, id4;
462
463 u16 client;
419 u8 def_ttl; 464 u8 def_ttl;
465 u8 r0;
420 466
421 u16 client; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
422 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
423 471
424 u16 max_size;
425 u8 seq_cdc;
426 u8 req_cdc;
427
428 u8 rep_cdc;
429 u8 delay; // time in 0.01s units that the server may delay replying packets
430 u8 r3, r4;
431
432 u8 r5, r6, r7, r8; 472 u8 r1, r2, r3, r4;
433 473
434 void reset (int clientid); 474 void reset (int clientid);
435 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
436}; 477};
437 478
438int dns_cfg::next_uid; 479int dns_cfg::next_uid;
439 480
481void
440void dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
441{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
442 id1 = 'G'; 485 id1 = 'G';
443 id2 = 'V'; 486 id2 = 'V';
444 id3 = 'P'; 487 id3 = 'P';
445 id4 = 'E'; 488 id4 = 'E';
446 489
447 version = 1; 490 version = 2;
448 491
449 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
450 flags = 0; 493 flags = 0;
451 def_ttl = 0; 494 def_ttl = 0;
452 seq_cdc = 26; 495 syn_cdc = 26;
453 req_cdc = 62; 496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
454 rep_cdc = 0; 498 rep_cdc = 0;
455 max_size = htons (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
456 client = htons (clientid); 500 client = htons (clientid);
457 uid = next_uid++; 501 uid = ++next_uid;
458 delay = 0;
459 502
460 r3 = r4 = 0; 503 r0 = r1 = r2 = r3 = r4 = 0;
461 r4 = r5 = r6 = r7 = 0;
462}
463 504
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
464bool dns_cfg::valid () 526dns_cfg::valid ()
465{ 527{
528 // although the protocol itself allows for some configurability,
529 // only the following encoding/decoding settings are implemented.
466 return id1 == 'G' 530 return id1 == 'G'
467 && id2 == 'V' 531 && id2 == 'V'
468 && id3 == 'P' 532 && id3 == 'P'
469 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
470 && seq_cdc == 26 535 && syn_cdc == 26
471 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
472 && rep_cdc == 0 538 && rep_cdc == 0
473 && version == 1; 539 && chksum == get_chksum ();
474} 540}
475 541
476struct dns_packet : net_packet 542struct dns_packet : net_packet
477{ 543{
478 u16 id; 544 u16 id;
… …
482 u8 data [MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
483 549
484 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
485}; 551};
486 552
553int
487int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
488{ 555{
489 char *orig = data; 556 char *orig = data;
490 557
491 memset (data, 0, size); 558 memset (data, 0, size);
492 559
… …
518 return data - orig; 585 return data - orig;
519} 586}
520 587
521///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
522 589
590static
591u16 next_id ()
592{
523static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
524 594
525static u16 next_id ()
526{
527 if (!dns_id) 595 if (!dns_id)
528 dns_id = time (0); 596 dns_id = time (0);
529 597
530 // the simplest lsfr with periodicity 65535 i could find 598 // the simplest lsfr with periodicity 65535 i could find
531 dns_id = (dns_id << 1) 599 dns_id = (dns_id << 1)
… …
546 struct vpn *vpn; 614 struct vpn *vpn;
547 615
548 dns_cfg cfg; 616 dns_cfg cfg;
549 617
550 bool established; 618 bool established;
619 const basecoder *cdc;
551 620
552 tstamp last_received; 621 tstamp last_received;
553 tstamp last_sent; 622 tstamp last_sent;
554 double min_latency; 623 double min_latency;
555 double poll_interval, send_interval; 624 double poll_interval, send_interval;
… …
557 vector<dns_rcv *> rcvpq; 626 vector<dns_rcv *> rcvpq;
558 627
559 byte_stream rcvdq; int rcvseq; int repseq; 628 byte_stream rcvdq; int rcvseq; int repseq;
560 byte_stream snddq; int sndseq; 629 byte_stream snddq; int sndseq;
561 630
562 void time_cb (time_watcher &w); time_watcher tw; 631 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
563 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
564 636
565 dns_connection (connection *c); 637 dns_connection (connection *c);
566 ~dns_connection (); 638 ~dns_connection ();
567}; 639};
568 640
… …
586: dns (dns) 658: dns (dns)
587{ 659{
588 timeout = 0; 660 timeout = 0;
589 retry = 0; 661 retry = 0;
590 seqno = 0; 662 seqno = 0;
591 sent = NOW; 663 sent = ev_now ();
592 stdhdr = false; 664 stdhdr = false;
593 665
594 pkt = new dns_packet; 666 pkt = new dns_packet;
595 667
596 pkt->id = next_id (); 668 pkt->id = next_id ();
… …
599dns_snd::~dns_snd () 671dns_snd::~dns_snd ()
600{ 672{
601 delete pkt; 673 delete pkt;
602} 674}
603 675
676static void
604static void append_domain (dns_packet &pkt, int &offs, const char *domain) 677append_domain (dns_packet &pkt, int &offs, const char *domain)
605{ 678{
606 // add tunnel domain 679 // add tunnel domain
607 for (;;) 680 for (;;)
608 { 681 {
609 const char *end = strchr (domain, '.'); 682 const char *end = strchr (domain, '.');
… …
622 695
623 domain = end + 1; 696 domain = end + 1;
624 } 697 }
625} 698}
626 699
700void
627void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 701dns_snd::gen_stream_req (int seqno, byte_stream &stream)
628{ 702{
629 stdhdr = true; 703 stdhdr = true;
630 this->seqno = seqno; 704 this->seqno = seqno;
631 705
632 timeout = NOW + INITIAL_TIMEOUT; 706 timeout = ev_now () + INITIAL_TIMEOUT;
633 707
634 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 708 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
635 pkt->qdcount = htons (1); 709 pkt->qdcount = htons (1);
636 710
637 int offs = 6*2; 711 int offs = 6*2;
… …
640 // 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
641 715
642 char enc[256], *encp = enc; 716 char enc[256], *encp = enc;
643 encode_header (enc, THISNODE->id, seqno); 717 encode_header (enc, THISNODE->id, seqno);
644 718
645 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);
646 720
647 if (datalen > stream.size ()) 721 if (datalen > stream.size ())
648 datalen = stream.size (); 722 datalen = stream.size ();
649 723
650 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 724 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
651 stream.remove (datalen); 725 stream.remove (datalen);
652 726
653 while (enclen) 727 while (enclen)
654 { 728 {
655 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 729 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
670 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 744 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
671 745
672 pkt->len = offs; 746 pkt->len = offs;
673} 747}
674 748
749void
675void dns_snd::gen_syn_req () 750dns_snd::gen_syn_req ()
676{ 751{
677 timeout = NOW + INITIAL_SYN_TIMEOUT; 752 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
678 753
679 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 754 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
680 pkt->qdcount = htons (1); 755 pkt->qdcount = htons (1);
681 756
682 int offs = 6 * 2; 757 int offs = 6 * 2;
… …
722 797
723dns_connection::dns_connection (connection *c) 798dns_connection::dns_connection (connection *c)
724: c (c) 799: c (c)
725, rcvdq (MAX_BACKLOG * 2) 800, rcvdq (MAX_BACKLOG * 2)
726, snddq (MAX_BACKLOG) 801, snddq (MAX_BACKLOG)
727, tw (this, &dns_connection::time_cb)
728{ 802{
803 tw.set<dns_connection, &dns_connection::time_cb> (this);
804
729 vpn = c->vpn; 805 vpn = c->vpn;
730 806
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
731 established = false; 831 established = false;
732 832
733 rcvseq = repseq = sndseq = 0; 833 rcvseq = repseq = sndseq = 0;
734 834
735 last_sent = last_received = 0; 835 last_sent = 0;
736 poll_interval = 0.5; // starting here 836 poll_interval = 0.5; // starting here
737 send_interval = 0.5; // starting rate 837 send_interval = 0.5; // starting rate
738 min_latency = INITIAL_TIMEOUT; 838 min_latency = INITIAL_TIMEOUT;
739} 839}
740 840
741dns_connection::~dns_connection () 841void
842dns_connection::set_cfg ()
742{ 843{
743 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 844 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
744 i != rcvpq.end ();
745 ++i)
746 delete *i;
747} 845}
748 846
847void
749void dns_connection::receive_rep (dns_rcv *r) 848dns_connection::receive_rep (dns_rcv *r)
750{ 849{
751 if (r->datalen) 850 if (r->datalen)
752 { 851 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
753 last_received = NOW;
754 tw.trigger ();
755
756 poll_interval = send_interval;
757 }
758 else 852 else
759 { 853 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
760 poll_interval *= 1.5;
761
762 if (poll_interval > MAX_POLL_INTERVAL)
763 poll_interval = MAX_POLL_INTERVAL;
764 }
765 854
766 rcvpq.push_back (r); 855 rcvpq.push_back (r);
767 856
768 redo: 857 redo:
769 858
770 // find next packet 859 // find next packet
771 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 860 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
772 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 861 if (SEQNO_EQ (rcvseq, (*i)->seqno))
773 { 862 {
863 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
774 // enter the packet into our input stream 864 // enter the packet into our input stream
775 r = *i; 865 r = *i;
776 866
777 // remove the oldest packet, look forward, as it's oldest first 867 // remove the oldest packet, look forward, as it's oldest first
778 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)
779 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 869 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
780 { 870 {
871 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
781 delete *j; 872 delete *j;
782 rcvpq.erase (j); 873 rcvpq.erase (j);
783 break; 874 break;
784 } 875 }
785 876
786 rcvseq = (rcvseq + 1) & SEQNO_MASK; 877 rcvseq = (rcvseq + 1) & SEQNO_MASK;
787 878
788 if (!rcvdq.put (r->data, r->datalen)) 879 if (!rcvdq.put (r->data, r->datalen))
789 { 880 {
881 // MUST never overflow, can be caused by data corruption, TODO
790 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 882 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
791 abort (); // MUST never overflow, can be caused by data corruption, TODO 883 reset ();
884 return;
792 } 885 }
793 886
794 while (vpn_packet *pkt = rcvdq.get ()) 887 while (vpn_packet *pkt = rcvdq.get ())
795 { 888 {
796 sockinfo si; 889 sockinfo si;
797 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;
798 891
799 vpn->recv_vpn_packet (pkt, si); 892 vpn->recv_vpn_packet (pkt, si);
800
801 delete pkt; 893 delete pkt;
802 } 894 }
803 895
804 // check for further packets 896 // check for further packets
805 goto redo; 897 goto redo;
… …
848 { 940 {
849 // correct class, domain: parse 941 // correct class, domain: parse
850 int client, seqno; 942 int client, seqno;
851 decode_header (qname, client, seqno); 943 decode_header (qname, client, seqno);
852 944
853 u8 data[MAXSIZE];
854 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
855
856 if (0 < client && client <= conns.size ()) 945 if (0 < client && client <= conns.size ())
857 { 946 {
858 connection *c = conns [client - 1]; 947 connection *c = conns [client - 1];
859 dns_connection *dns = c->dns; 948 dns_connection *dns = c->dns;
860 dns_rcv *rcv; 949 dns_rcv *rcv;
861 950
862 if (dns) 951 if (dns)
863 { 952 {
953 u8 data[MAXSIZE];
954 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
955
864 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 (); )
865 if (SEQNO_EQ ((*i)->seqno, seqno)) 957 if (SEQNO_EQ ((*i)->seqno, seqno))
866 { 958 {
867 // already seen that request: simply reply with the cached reply 959 // already seen that request: simply reply with the cached reply
868 dns_rcv *r = *i; 960 dns_rcv *r = *i;
… …
969 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
970 pkt [offs++] = 0; pkt [offs++] = 0; 1062 pkt [offs++] = 0; pkt [offs++] = 0;
971 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1063 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
972 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1064 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
973 1065
974 slog (L_INFO, _("DNS: client %d connects"), client);
975
976 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;
977 pkt [offs++] = CMD_IP_REJ; 1067 pkt [offs++] = CMD_IP_REJ;
978 1068
979 if (0 < client && client <= conns.size ()) 1069 if (0 < client && client <= conns.size ())
980 { 1070 {
981 connection *c = conns [client - 1]; 1071 connection *c = conns [client - 1];
982 1072
983 if (cfg.valid ()) 1073 if (cfg.valid ())
984 { 1074 {
985 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));
986 1080
987 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
988 c->dns = new dns_connection (c); 1086 c->dns = new dns_connection (c);
989 c->dns->cfg = cfg; 1087 c->dns->cfg = cfg;
1088 c->dns->set_cfg ();
990 } 1089 }
991 } 1090 }
992 } 1091 }
993 } 1092 }
994 1093
… …
1013 { 1112 {
1014 dns_connection *dns = (*i)->dns; 1113 dns_connection *dns = (*i)->dns;
1015 connection *c = dns->c; 1114 connection *c = dns->c;
1016 int seqno = (*i)->seqno; 1115 int seqno = (*i)->seqno;
1017 u8 data[MAXSIZE], *datap = data; 1116 u8 data[MAXSIZE], *datap = data;
1117 //printf ("rcv pkt %x\n", seqno);//D
1018 1118
1019 if ((*i)->retry) 1119 if ((*i)->retry)
1020 { 1120 {
1021 dns->send_interval *= 1.01; 1121 dns->send_interval *= 1.01;
1022 if (dns->send_interval > MAX_SEND_INTERVAL) 1122 if (dns->send_interval > MAX_SEND_INTERVAL)
… …
1027#if 0 1127#if 0
1028 dns->send_interval *= 0.999; 1128 dns->send_interval *= 0.999;
1029#endif 1129#endif
1030 // the latency surely puts an upper bound on 1130 // the latency surely puts an upper bound on
1031 // the minimum send interval 1131 // the minimum send interval
1032 double latency = NOW - (*i)->sent; 1132 double latency = ev_now () - (*i)->sent;
1033 1133
1034 if (latency < dns->min_latency) 1134 if (latency < dns->min_latency)
1035 dns->min_latency = latency; 1135 dns->min_latency = latency;
1036 1136
1037 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) 1137 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
… …
1064 ttl |= pkt [offs++] << 16; 1164 ttl |= pkt [offs++] << 16;
1065 ttl |= pkt [offs++] << 8; 1165 ttl |= pkt [offs++] << 8;
1066 ttl |= pkt [offs++]; 1166 ttl |= pkt [offs++];
1067 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1167 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1068 1168
1069 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1169 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1070 { 1170 {
1071 if (rdlen <= MAXSIZE - offs) 1171 if (rdlen <= MAXSIZE - offs)
1072 { 1172 {
1073 // decode bytes, finally 1173 // decode bytes, finally
1074 1174
… …
1100 { 1200 {
1101 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1201 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1102 1202
1103 if (ip [3] == CMD_IP_RST) 1203 if (ip [3] == CMD_IP_RST)
1104 { 1204 {
1105 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1205 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1106 1206
1107 delete dns; c->dns = 0; 1207 dns->reset ();
1108
1109 return; 1208 return;
1110 } 1209 }
1111 else if (ip [3] == CMD_IP_SYN) 1210 else if (ip [3] == CMD_IP_SYN)
1112 { 1211 {
1113 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1212 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1114 dns->established = true; 1213 dns->established = true;
1115 } 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 }
1116 else if (ip [3] == CMD_IP_REJ) 1230 else if (ip [3] == CMD_IP_REJ)
1117 { 1231 {
1118 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."));
1119 abort (); 1233 dns->tw.start (60.);
1120 } 1234 }
1121 else 1235 else
1236 {
1122 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 }
1123 } 1240 }
1124 else 1241 else
1125 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"),
1126 ip [0], ip [1], ip [2], ip [3]); 1243 ip [0], ip [1], ip [2], ip [3]);
1127 1244
… …
1151 break; 1268 break;
1152 } 1269 }
1153} 1270}
1154 1271
1155void 1272void
1156vpn::dnsv4_ev (io_watcher &w, short revents) 1273vpn::dnsv4_ev (ev::io &w, int revents)
1157{ 1274{
1158 if (revents & EVENT_READ) 1275 if (revents & EV_READ)
1159 { 1276 {
1160 dns_packet *pkt = new dns_packet; 1277 dns_packet *pkt = new dns_packet;
1161 struct sockaddr_in sa; 1278 struct sockaddr_in sa;
1162 socklen_t sa_len = sizeof (sa); 1279 socklen_t sa_len = sizeof (sa);
1163 1280
… …
1189 1306
1190 if (!c->dns) 1307 if (!c->dns)
1191 c->dns = new dns_connection (c); 1308 c->dns = new dns_connection (c);
1192 1309
1193 if (c->dns->snddq.put (pkt)) 1310 if (c->dns->snddq.put (pkt))
1311 {
1312 min_it (c->dns->poll_interval, 0.25);
1194 c->dns->tw.trigger (); 1313 c->dns->tw ();
1314 }
1195 1315
1196 // always return true even if the buffer overflows 1316 // always return true even if the buffer overflows
1197 return true; 1317 return true;
1198} 1318}
1199 1319
1200void 1320void
1201connection::dnsv4_reset_connection () 1321dns_connection::time_cb (ev::timer &w, int revents)
1202{
1203 //delete dns; dns = 0; //TODO
1204}
1205
1206#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1207
1208void
1209dns_connection::time_cb (time_watcher &w)
1210{ 1322{
1211 // servers have to be polled 1323 // servers have to be polled
1212 if (THISNODE->dns_port) 1324 if (THISNODE->dns_port)
1213 return; 1325 return;
1214 1326
1215 // check for timeouts and (re)transmit 1327 // check for timeouts and (re)transmit
1216 tstamp next = NOW + poll_interval; 1328 tstamp next = 86400 * 365;
1217 dns_snd *send = 0; 1329 dns_snd *send = 0;
1218 1330
1219 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1331 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1220 i != vpn->dns_sndpq.end (); 1332 i != vpn->dns_sndpq.end ();
1221 ++i) 1333 ++i)
1222 { 1334 {
1223 dns_snd *r = *i; 1335 dns_snd *r = *i;
1224 1336
1225 if (r->timeout <= NOW) 1337 if (r->timeout <= ev_now ())
1226 { 1338 {
1227 if (!send) 1339 if (!send)
1228 { 1340 {
1229 send = r; 1341 send = r;
1230 1342
1231 r->retry++; 1343 r->retry++;
1232 r->timeout = NOW + (r->retry * min_latency * conf.dns_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
1233 1346
1234 // the following code changes the query section a bit, forcing 1347 // the following code changes the query section a bit, forcing
1235 // the forwarder to generate a new request 1348 // the forwarder to generate a new request
1236 if (r->stdhdr) 1349 if (r->stdhdr)
1237 {
1238 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1239 //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);
1240 }
1241 } 1351 }
1242 } 1352 }
1243 else 1353 else
1244 NEXT (r->timeout); 1354 min_it (next, r->timeout - ev_now ());
1245 } 1355 }
1246 1356
1247 if (!send) 1357 if (!send)
1248 { 1358 {
1249 // generate a new packet, if wise 1359 // generate a new packet, if wise
… …
1253 if (vpn->dns_sndpq.empty ()) 1363 if (vpn->dns_sndpq.empty ())
1254 { 1364 {
1255 send = new dns_snd (this); 1365 send = new dns_snd (this);
1256 1366
1257 cfg.reset (THISNODE->id); 1367 cfg.reset (THISNODE->id);
1368 set_cfg ();
1258 send->gen_syn_req (); 1369 send->gen_syn_req ();
1259 } 1370 }
1260 } 1371 }
1261 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1372 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1262 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1373 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1263 { 1374 {
1264 if (last_sent + send_interval <= NOW) 1375 if (last_sent + send_interval <= ev_now ())
1265 { 1376 {
1266 //printf ("sending data request etc.\n"); //D 1377 //printf ("sending data request etc.\n"); //D
1267 if (!snddq.empty () || last_received + 1. > NOW) 1378 if (!snddq.empty ())
1268 {
1269 poll_interval = send_interval;
1270 NEXT (NOW + send_interval); 1379 min_it (next, send_interval);
1271 }
1272 1380
1273 send = new dns_snd (this); 1381 send = new dns_snd (this);
1274 send->gen_stream_req (sndseq, snddq); 1382 send->gen_stream_req (sndseq, snddq);
1275 send->timeout = NOW + min_latency * conf.dns_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
1276 1385
1277 sndseq = (sndseq + 1) & SEQNO_MASK; 1386 sndseq = (sndseq + 1) & SEQNO_MASK;
1278 } 1387 }
1279 else 1388 else
1280 NEXT (last_sent + send_interval); 1389 min_it (next, last_sent + send_interval - ev_now ());
1281 } 1390 }
1282 1391
1283 if (send) 1392 if (send)
1284 vpn->dns_sndpq.push_back (send); 1393 vpn->dns_sndpq.push_back (send);
1285 } 1394 }
1286 1395
1287 if (send) 1396 if (send)
1288 { 1397 {
1289 last_sent = NOW; 1398 last_sent = ev_now ();
1290 sendto (vpn->dnsv4_fd, 1399 sendto (vpn->dnsv4_fd,
1291 send->pkt->at (0), send->pkt->len, 0, 1400 send->pkt->at (0), send->pkt->len, 0,
1292 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1401 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1293 } 1402 }
1294 1403
1404 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1405
1295 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)",
1296 poll_interval, send_interval, next - NOW, 1407 poll_interval, send_interval, next - ev_now (),
1297 vpn->dns_sndpq.size (), snddq.size (), 1408 vpn->dns_sndpq.size (), snddq.size (),
1298 rcvpq.size ()); 1409 rcvpq.size ());
1299 1410
1300 // TODO: no idea when this happens, but when next < NOW, we have a problem
1301 // doesn't seem to happen anymore
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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