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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.45 by pcg, Tue Dec 4 17:17:20 2007 UTC vs.
Revision 1.54 by root, Tue Oct 18 11:07:28 2011 UTC

1/* 1/*
2 vpn_dns.C -- handle the dns tunnel part of the protocol. 2 vpn_dns.C -- handle the dns tunnel part of the protocol.
3 Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de> 3 Copyright (C) 2003-2011 Marc Lehmann <gvpe@schmorp.de>
4 4
5 This file is part of GVPE. 5 This file is part of GVPE.
6 6
7 GVPE is free software; you can redistribute it and/or modify 7 GVPE is free software; you can redistribute it and/or modify it
8 it under the terms of the GNU General Public License as published by 8 under the terms of the GNU General Public License as published by the
9 the Free Software Foundation; either version 2 of the License, or 9 Free Software Foundation; either version 3 of the License, or (at your
10 (at your option) any later version. 10 option) any later version.
11 11
12 This program is distributed in the hope that it will be useful, 12 This program is distributed in the hope that it will be useful, but
13 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15 GNU General Public License for more details. 15 Public License for more details.
16 16
17 You should have received a copy of the GNU General Public License 17 You should have received a copy of the GNU General Public License along
18 along with gvpe; if not, write to the Free Software 18 with this program; if not, see <http://www.gnu.org/licenses/>.
19 Foundation, Inc. 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.
… …
49 59
50#include "netcompat.h" 60#include "netcompat.h"
51 61
52#include "vpn.h" 62#include "vpn.h"
53 63
64#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received
54#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
55#define ACTIVITY_INTERVAL 5.
56 66
57#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
58#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
59 69
60#define MAX_SEND_INTERVAL 2. // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
61 71
62#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
63#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE 73#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
64 74
65#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well 75#define MAX_DOMAIN_SIZE 235 // 255 is legal limit, but bind doesn't compress well
66// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
67// every request byte less give room for two reply bytes 77// every request byte less give room for two reply bytes
68 78
69#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
70#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
… …
73#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
74 84
75#define RR_TYPE_A 1 85#define RR_TYPE_A 1
76#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
77#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
78#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
79 90
80#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
81 92
82#define CMD_IP_1 207 93#define CMD_IP_1 207
83#define CMD_IP_2 46 94#define CMD_IP_2 46
84#define CMD_IP_3 236 95#define CMD_IP_3 236
85#define CMD_IP_RST 29 96
86#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
87#define CMD_IP_REJ 32 98#define CMD_IP_REJ 32 // do not want you
99#define CMD_IP_SYN 113 // connection established
100#define CMD_IP_CSE 213 // connection established, but likely case mismatch
101
102static bool
103is_uc (char c)
104{
105 return 'A' <= c && c <= 'Z';
106}
107
108static bool
109is_lc (char c)
110{
111 return 'a' <= c && c <= 'z';
112}
88 113
89// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
90struct charmap 115struct charmap
91{ 116{
92 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
106 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
107 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
108 133
109 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
110 { 135 {
136 char c = cmap [size];
137
111 enc [size] = cmap [size]; 138 enc [size] = c;
112 dec [(u8)enc [size]] = size; 139 dec [(u8)c] = size;
140
141 // allow lowercase/uppercase aliases if possible
142 if (is_uc (c) && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size;
143 if (is_lc (c) && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size;
113 } 144 }
114 145
115 assert (size < 256); 146 assert (size < 256);
116} 147}
117 148
… …
124{ 155{
125 charmap cmap; 156 charmap cmap;
126 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
127 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
128 159
129 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
130 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
131 162
132 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
133 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
134 165
135 basecoder (const char *cmap); 166 basecoder (const char *cmap);
136}; 167};
137 168
138basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
157 enc_len [len] = n; 188 enc_len [len] = n;
158 dec_len [n] = len; 189 dec_len [n] = len;
159 } 190 }
160} 191}
161 192
193unsigned int
162unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
163{ 195{
164 return enc_len [len]; 196 return enc_len [len];
165} 197}
166 198
199unsigned int
167unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
168{ 201{
169 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
170 --len; 203 --len;
171 204
172 return dec_len [len]; 205 return dec_len [len];
173} 206}
174 207
208unsigned int
175unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
176{ 210{
177 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
178 return 0; 212 return 0;
179 213
180 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
199 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
200 234
201 return elen; 235 return elen;
202} 236}
203 237
238unsigned int
204unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
205{ 240{
206 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
207 return 0; 242 return 0;
208 243
209 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
258 } 293 }
259 abort (); 294 abort ();
260} 295}
261#endif 296#endif
262 297
263//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
264//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
265static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
266//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
267static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
268 301
269///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
270 303
271#define HDRSIZE 6 304#define HDRSIZE 5
272 305
306inline void
273inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
274{ 308{
309 assert (clientid < 256);
310
275 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
276 312
277 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
278 clientid, 316 clientid,
279 (seqno >> 8) | (retry << 6),
280 seqno,
281 }; 317 };
282 318
283 assert (clientid < 256);
284
285 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
286} 320}
287 321
322inline void
288inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
289{ 324{
290 u8 hdr[3]; 325 u8 hdr[3];
291 326
292 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
293 328
294 clientid = hdr[0]; 329 clientid = hdr[2];
295 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
296} 331}
297 332
298///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
299 334
300struct byte_stream 335struct byte_stream
… …
326byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
327{ 362{
328 delete data; 363 delete data;
329} 364}
330 365
366void
331void byte_stream::remove (int count) 367byte_stream::remove (int count)
332{ 368{
333 if (count > fill) 369 if (count > fill)
334 assert (count <= fill); 370 assert (count <= fill);
335 371
336 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
337} 373}
338 374
375bool
339bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
340{ 377{
341 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
342 return false; 379 return false;
343 380
344 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
345 382
346 return true; 383 return true;
347} 384}
348 385
386bool
349bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
350{ 388{
351 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
352 return false; 390 return false;
353 391
354 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
… …
359 return true; 397 return true;
360} 398}
361 399
362vpn_packet *byte_stream::get () 400vpn_packet *byte_stream::get ()
363{ 401{
402 if (fill < 2)
403 return 0;
404
364 unsigned int len; 405 unsigned int len;
365 406
366 for (;;) 407 for (;;)
367 { 408 {
368 len = (data [0] << 8) | data [1]; 409 len = (data [0] << 8) | data [1];
369 410
370 if (len <= MAXSIZE || fill < 2) 411 if (len <= MAXSIZE)
371 break; 412 break;
372 413
373 // TODO: handle this better than skipping, e.g. by reset 414 // TODO: handle this better than skipping, e.g. by reset
374 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte...")); 415 slog (L_DEBUG, _("DNS: corrupted packet (%02x %02x) stream skipping a byte..."), data [0], data [1]);
375 remove (1); 416 remove (1);
376 } 417 }
377 418
378 if (fill < len + 2) 419 if (fill < len + 2)
379 return 0; 420 return 0;
… …
410 451
411struct dns_cfg 452struct dns_cfg
412{ 453{
413 static int next_uid; 454 static int next_uid;
414 455
415 u8 id1, id2, id3, id4; 456 u8 chksum;
457 u8 rrtype;
458 u16 uid; // to make request unique
416 459
417 u8 version; 460 u8 version;
418 u8 flags; 461 u8 flags;
419 u8 rrtype; 462 u16 max_size;
463
464 u8 id1, id2, id3, id4;
465
466 u16 client;
420 u8 def_ttl; 467 u8 def_ttl;
468 u8 r0;
421 469
422 u16 client; 470 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
423 u16 uid; // to make request unique 471 u8 hdr_cdc; // cdc en/decoder for regular request headers
472 u8 req_cdc; // cdc en/decoder for regular (ANY?) request data
473 u8 rep_cdc; // cdc en/decoder for regular (TXT) replies, 0 == 8 bit encoding
424 474
425 u16 max_size;
426 u8 seq_cdc;
427 u8 req_cdc;
428
429 u8 rep_cdc;
430 u8 delay; // time in 0.01s units that the server may delay replying packets
431 u8 r3, r4;
432
433 u8 r5, r6, r7, r8; 475 u8 r1, r2, r3, r4;
434 476
435 void reset (int clientid); 477 void reset (int clientid);
436 bool valid (); 478 bool valid ();
479 u8 get_chksum ();
437}; 480};
438 481
439int dns_cfg::next_uid; 482int dns_cfg::next_uid;
440 483
484void
441void dns_cfg::reset (int clientid) 485dns_cfg::reset (int clientid)
442{ 486{
487 // this ID must result in some mixed-case characters in cdc26-encoding
443 id1 = 'G'; 488 id1 = 'G';
444 id2 = 'V'; 489 id2 = 'V';
445 id3 = 'P'; 490 id3 = 'P';
446 id4 = 'E'; 491 id4 = 'E';
447 492
448 version = 1; 493 version = 2;
449 494
450 rrtype = RR_TYPE_TXT; 495 rrtype = RR_TYPE_TXT;
451 flags = 0; 496 flags = 0;
452 def_ttl = 0; 497 def_ttl = 0;
453 seq_cdc = 26; 498 syn_cdc = 26;
454 req_cdc = 62; 499 hdr_cdc = 36;
500 req_cdc = conf.dns_case_preserving ? 62 : 36;
455 rep_cdc = 0; 501 rep_cdc = 0;
456 max_size = htons (MAX_PKT_SIZE); 502 max_size = htons (MAX_PKT_SIZE);
457 client = htons (clientid); 503 client = htons (clientid);
458 uid = next_uid++; 504 uid = ++next_uid;
459 delay = 0;
460 505
461 r3 = r4 = 0; 506 r0 = r1 = r2 = r3 = r4 = 0;
462 r4 = r5 = r6 = r7 = 0;
463}
464 507
508 chksum = get_chksum ();
509}
510
511// simple but not trivial chksum
512u8
513dns_cfg::get_chksum ()
514{
515 unsigned int sum = 0xff00; // only 16 bits required
516
517 u8 old_chksum = chksum;
518 chksum = 0;
519
520 for (unsigned int i = 0; i < sizeof (*this); ++i)
521 sum += ((u8 *)this)[i] * (i + 1);
522
523 chksum = old_chksum;
524
525 return sum + (sum >> 8);
526}
527
528bool
465bool dns_cfg::valid () 529dns_cfg::valid ()
466{ 530{
467 // although the protocol itself allows for some configurability, 531 // although the protocol itself allows for some configurability,
468 // only the following encoding/decoding settings are implemented. 532 // only the following encoding/decoding settings are implemented.
469 return id1 == 'G' 533 return id1 == 'G'
470 && id2 == 'V' 534 && id2 == 'V'
471 && id3 == 'P' 535 && id3 == 'P'
472 && id4 == 'E' 536 && id4 == 'E'
537 && version == 2
473 && seq_cdc == 26 538 && syn_cdc == 26
474 && req_cdc == 62 539 && hdr_cdc == 36
540 && (req_cdc == 36 || req_cdc == 62)
475 && rep_cdc == 0 541 && rep_cdc == 0
476 && version == 1; 542 && chksum == get_chksum ();
477} 543}
478 544
479struct dns_packet : net_packet 545struct dns_packet : net_packet
480{ 546{
481 u16 id; 547 u16 id;
… …
485 u8 data [MAXSIZE - 6 * 2]; 551 u8 data [MAXSIZE - 6 * 2];
486 552
487 int decode_label (char *data, int size, int &offs); 553 int decode_label (char *data, int size, int &offs);
488}; 554};
489 555
556int
490int dns_packet::decode_label (char *data, int size, int &offs) 557dns_packet::decode_label (char *data, int size, int &offs)
491{ 558{
492 char *orig = data; 559 char *orig = data;
493 560
494 memset (data, 0, size); 561 memset (data, 0, size);
495 562
… …
521 return data - orig; 588 return data - orig;
522} 589}
523 590
524///////////////////////////////////////////////////////////////////////////// 591/////////////////////////////////////////////////////////////////////////////
525 592
593static
594u16 next_id ()
595{
526static u16 dns_id = 0; // TODO: should be per-vpn 596 static u16 dns_id = 0; // TODO: should be per-vpn
527 597
528static u16 next_id () 598#if 1
529{
530 if (!dns_id) 599 if (!dns_id)
531 dns_id = time (0); 600 dns_id = time (0);
532 601
533 // the simplest lsfr with periodicity 65535 i could find 602 // the simplest lsfr with periodicity 65535 i could find
534 dns_id = (dns_id << 1) 603 dns_id = (dns_id << 1)
… …
536 ^ (dns_id >> 2) 605 ^ (dns_id >> 2)
537 ^ (dns_id >> 4) 606 ^ (dns_id >> 4)
538 ^ (dns_id >> 15)) & 1); 607 ^ (dns_id >> 15)) & 1);
539 608
540 return dns_id; 609 return dns_id;
610#else
611 dns_id++;//D
612
613 return htons (dns_id);
614#endif
541} 615}
542 616
543struct dns_rcv; 617struct dns_rcv;
544struct dns_snd; 618struct dns_snd;
545 619
… …
549 struct vpn *vpn; 623 struct vpn *vpn;
550 624
551 dns_cfg cfg; 625 dns_cfg cfg;
552 626
553 bool established; 627 bool established;
628 const basecoder *cdc;
554 629
555 tstamp last_received; 630 tstamp last_received;
556 tstamp last_sent; 631 tstamp last_sent;
557 double min_latency; 632 double min_latency;
558 double poll_interval, send_interval; 633 double poll_interval, send_interval;
… …
560 vector<dns_rcv *> rcvpq; 635 vector<dns_rcv *> rcvpq;
561 636
562 byte_stream rcvdq; int rcvseq; int repseq; 637 byte_stream rcvdq; int rcvseq; int repseq;
563 byte_stream snddq; int sndseq; 638 byte_stream snddq; int sndseq;
564 639
565 void time_cb (ev::timer &w, int revents); ev::timer tw; 640 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
566 void receive_rep (dns_rcv *r); 641 void receive_rep (dns_rcv *r);
642
643 void reset (); // quite like tcp RST
644 void set_cfg (); // to be called after any cfg changes
567 645
568 dns_connection (connection *c); 646 dns_connection (connection *c);
569 ~dns_connection (); 647 ~dns_connection ();
570}; 648};
571 649
… …
602dns_snd::~dns_snd () 680dns_snd::~dns_snd ()
603{ 681{
604 delete pkt; 682 delete pkt;
605} 683}
606 684
685static void
607static void append_domain (dns_packet &pkt, int &offs, const char *domain) 686append_domain (dns_packet &pkt, int &offs, const char *domain)
608{ 687{
609 // add tunnel domain 688 // add tunnel domain
610 for (;;) 689 for (;;)
611 { 690 {
612 const char *end = strchr (domain, '.'); 691 const char *end = strchr (domain, '.');
… …
625 704
626 domain = end + 1; 705 domain = end + 1;
627 } 706 }
628} 707}
629 708
709void
630void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 710dns_snd::gen_stream_req (int seqno, byte_stream &stream)
631{ 711{
632 stdhdr = true; 712 stdhdr = true;
633 this->seqno = seqno; 713 this->seqno = seqno;
634 714
635 timeout = ev_now () + INITIAL_TIMEOUT; 715 timeout = ev_now () + INITIAL_TIMEOUT;
… …
643 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 723 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
644 724
645 char enc[256], *encp = enc; 725 char enc[256], *encp = enc;
646 encode_header (enc, THISNODE->id, seqno); 726 encode_header (enc, THISNODE->id, seqno);
647 727
648 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 728 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
649 729
650 if (datalen > stream.size ()) 730 if (datalen > stream.size ())
651 datalen = stream.size (); 731 datalen = stream.size ();
652 732
653 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 733 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
654 stream.remove (datalen); 734 stream.remove (datalen);
655 735
656 while (enclen) 736 while (enclen)
657 { 737 {
658 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 738 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
673 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 753 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
674 754
675 pkt->len = offs; 755 pkt->len = offs;
676} 756}
677 757
758void
678void dns_snd::gen_syn_req () 759dns_snd::gen_syn_req ()
679{ 760{
680 timeout = ev_now () + INITIAL_SYN_TIMEOUT; 761 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
681 762
682 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 763 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
683 pkt->qdcount = htons (1); 764 pkt->qdcount = htons (1);
… …
730{ 811{
731 tw.set<dns_connection, &dns_connection::time_cb> (this); 812 tw.set<dns_connection, &dns_connection::time_cb> (this);
732 813
733 vpn = c->vpn; 814 vpn = c->vpn;
734 815
816 reset ();
817}
818
819dns_connection::~dns_connection ()
820{
821 reset ();
822}
823
824void
825dns_connection::reset ()
826{
827 while (!rcvpq.empty ())
828 {
829 delete rcvpq.back ();
830 rcvpq.pop_back ();
831 }
832
833 for (int i = vpn->dns_sndpq.size (); i--; )
834 if (vpn->dns_sndpq [i]->dns == this)
835 {
836 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
837 vpn->dns_sndpq.pop_back ();
838 }
839
735 established = false; 840 established = false;
736 841
737 rcvseq = repseq = sndseq = 0; 842 rcvseq = repseq = sndseq = 0;
738 843
739 last_sent = last_received = 0; 844 last_sent = 0;
740 poll_interval = 0.5; // starting here 845 poll_interval = 0.5; // starting here
741 send_interval = 0.5; // starting rate 846 send_interval = 0.5; // starting rate
742 min_latency = INITIAL_TIMEOUT; 847 min_latency = INITIAL_TIMEOUT;
743} 848}
744 849
745dns_connection::~dns_connection () 850void
851dns_connection::set_cfg ()
746{ 852{
747 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 853 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
748 i != rcvpq.end ();
749 ++i)
750 delete *i;
751} 854}
752 855
856void
753void dns_connection::receive_rep (dns_rcv *r) 857dns_connection::receive_rep (dns_rcv *r)
754{ 858{
755 if (r->datalen) 859 if (r->datalen)
756 { 860 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
757 last_received = ev_now ();
758 tw ();
759
760 poll_interval = send_interval;
761 }
762 else 861 else
763 { 862 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
764 poll_interval *= 1.5;
765
766 if (poll_interval > MAX_POLL_INTERVAL)
767 poll_interval = MAX_POLL_INTERVAL;
768 }
769 863
770 rcvpq.push_back (r); 864 rcvpq.push_back (r);
771 865
772 redo: 866 redo:
773 867
… …
791 885
792 rcvseq = (rcvseq + 1) & SEQNO_MASK; 886 rcvseq = (rcvseq + 1) & SEQNO_MASK;
793 887
794 if (!rcvdq.put (r->data, r->datalen)) 888 if (!rcvdq.put (r->data, r->datalen))
795 { 889 {
890 // MUST never overflow, can be caused by data corruption, TODO
796 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 891 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
797 abort (); // MUST never overflow, can be caused by data corruption, TODO 892 reset ();
893 return;
798 } 894 }
799 895
800 while (vpn_packet *pkt = rcvdq.get ()) 896 while (vpn_packet *pkt = rcvdq.get ())
801 { 897 {
802 sockinfo si; 898 sockinfo si;
803 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; 899 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
804 900
805 vpn->recv_vpn_packet (pkt, si); 901 vpn->recv_vpn_packet (pkt, si);
806
807 delete pkt; 902 delete pkt;
808 } 903 }
809 904
810 // check for further packets 905 // check for further packets
811 goto redo; 906 goto redo;
… …
854 { 949 {
855 // correct class, domain: parse 950 // correct class, domain: parse
856 int client, seqno; 951 int client, seqno;
857 decode_header (qname, client, seqno); 952 decode_header (qname, client, seqno);
858 953
859 u8 data[MAXSIZE];
860 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
861
862 if (0 < client && client <= conns.size ()) 954 if (0 < client && client <= conns.size ())
863 { 955 {
864 connection *c = conns [client - 1]; 956 connection *c = conns [client - 1];
865 dns_connection *dns = c->dns; 957 dns_connection *dns = c->dns;
866 dns_rcv *rcv; 958 dns_rcv *rcv;
867 959
868 if (dns) 960 if (dns)
869 { 961 {
962 u8 data[MAXSIZE];
963 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
964
870 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 965 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
871 if (SEQNO_EQ ((*i)->seqno, seqno)) 966 if (SEQNO_EQ ((*i)->seqno, seqno))
872 { 967 {
873 // already seen that request: simply reply with the cached reply 968 // already seen that request: simply reply with the cached reply
874 dns_rcv *r = *i; 969 dns_rcv *r = *i;
… …
975 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1070 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
976 pkt [offs++] = 0; pkt [offs++] = 0; 1071 pkt [offs++] = 0; pkt [offs++] = 0;
977 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1072 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
978 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1073 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
979 1074
980 slog (L_INFO, _("DNS: client %d connects"), client);
981
982 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1075 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
983 pkt [offs++] = CMD_IP_REJ; 1076 pkt [offs++] = CMD_IP_REJ;
984 1077
985 if (0 < client && client <= conns.size ()) 1078 if (0 < client && client <= conns.size ())
986 { 1079 {
987 connection *c = conns [client - 1]; 1080 connection *c = conns [client - 1];
988 1081
989 if (cfg.valid ()) 1082 if (cfg.valid ())
990 { 1083 {
991 pkt [offs - 1] = CMD_IP_SYN; 1084 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1085
1086 // check for any encoding mismatches - hints at a case problem
1087 char qname2 [MAX_ENC_LEN];
1088 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
992 1089
993 delete c->dns; 1090 delete c->dns;
1091
1092 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1093 ? CMD_IP_CSE : CMD_IP_SYN;
1094
994 c->dns = new dns_connection (c); 1095 c->dns = new dns_connection (c);
995 c->dns->cfg = cfg; 1096 c->dns->cfg = cfg;
1097 c->dns->set_cfg ();
996 } 1098 }
997 } 1099 }
998 } 1100 }
999 } 1101 }
1000 1102
… …
1071 ttl |= pkt [offs++] << 16; 1173 ttl |= pkt [offs++] << 16;
1072 ttl |= pkt [offs++] << 8; 1174 ttl |= pkt [offs++] << 8;
1073 ttl |= pkt [offs++]; 1175 ttl |= pkt [offs++];
1074 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1176 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1075 1177
1076 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1178 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1077 { 1179 {
1078 if (rdlen <= MAXSIZE - offs) 1180 if (rdlen <= MAXSIZE - offs)
1079 { 1181 {
1080 // decode bytes, finally 1182 // decode bytes, finally
1081 1183
… …
1107 { 1209 {
1108 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1210 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1109 1211
1110 if (ip [3] == CMD_IP_RST) 1212 if (ip [3] == CMD_IP_RST)
1111 { 1213 {
1112 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1214 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1113 1215
1114 delete dns; c->dns = 0; 1216 dns->reset ();
1115
1116 return; 1217 return;
1117 } 1218 }
1118 else if (ip [3] == CMD_IP_SYN) 1219 else if (ip [3] == CMD_IP_SYN)
1119 { 1220 {
1120 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1221 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1121 dns->established = true; 1222 dns->established = true;
1122 } 1223 }
1224 else if (ip [3] == CMD_IP_CSE)
1225 {
1226 if (conf.dns_case_preserving)
1227 {
1228 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1229 conf.dns_case_preserving = false;
1230 dns->reset ();
1231 return;
1232 }
1233 else
1234 {
1235 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1236 dns->established = true;
1237 }
1238 }
1123 else if (ip [3] == CMD_IP_REJ) 1239 else if (ip [3] == CMD_IP_REJ)
1124 { 1240 {
1125 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1241 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1126 abort (); 1242 dns->tw.start (60.);
1127 } 1243 }
1128 else 1244 else
1245 {
1129 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1246 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1247 dns->tw.start (60.);
1248 }
1130 } 1249 }
1131 else 1250 else
1132 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1251 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1133 ip [0], ip [1], ip [2], ip [3]); 1252 ip [0], ip [1], ip [2], ip [3]);
1134 1253
… …
1196 1315
1197 if (!c->dns) 1316 if (!c->dns)
1198 c->dns = new dns_connection (c); 1317 c->dns = new dns_connection (c);
1199 1318
1200 if (c->dns->snddq.put (pkt)) 1319 if (c->dns->snddq.put (pkt))
1320 {
1321 min_it (c->dns->poll_interval, 0.25);
1201 c->dns->tw (); 1322 c->dns->tw ();
1323 }
1202 1324
1203 // always return true even if the buffer overflows 1325 // always return true even if the buffer overflows
1204 return true; 1326 return true;
1205} 1327}
1206
1207void
1208connection::dnsv4_reset_connection ()
1209{
1210 //delete dns; dns = 0; //TODO
1211}
1212
1213#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1214 1328
1215void 1329void
1216dns_connection::time_cb (ev::timer &w, int revents) 1330dns_connection::time_cb (ev::timer &w, int revents)
1217{ 1331{
1218 // servers have to be polled 1332 // servers have to be polled
1219 if (THISNODE->dns_port) 1333 if (THISNODE->dns_port)
1220 return; 1334 return;
1221 1335
1222 // check for timeouts and (re)transmit 1336 // check for timeouts and (re)transmit
1223 tstamp next = ev::now () + poll_interval; 1337 tstamp next = 86400 * 365;
1224 dns_snd *send = 0; 1338 dns_snd *send = 0;
1225 1339
1226 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1340 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1227 i != vpn->dns_sndpq.end (); 1341 i != vpn->dns_sndpq.end ();
1228 ++i) 1342 ++i)
… …
1234 if (!send) 1348 if (!send)
1235 { 1349 {
1236 send = r; 1350 send = r;
1237 1351
1238 r->retry++; 1352 r->retry++;
1239 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); 1353 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1240 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D 1354 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1241 1355
1242 // the following code changes the query section a bit, forcing 1356 // the following code changes the query section a bit, forcing
1243 // the forwarder to generate a new request 1357 // the forwarder to generate a new request
1244 if (r->stdhdr) 1358 if (r->stdhdr)
1245 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1359 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1246 } 1360 }
1247 } 1361 }
1248 else 1362 else
1249 NEXT (r->timeout); 1363 min_it (next, r->timeout - ev_now ());
1250 } 1364 }
1251 1365
1252 if (!send) 1366 if (!send)
1253 { 1367 {
1254 // generate a new packet, if wise 1368 // generate a new packet, if wise
… …
1258 if (vpn->dns_sndpq.empty ()) 1372 if (vpn->dns_sndpq.empty ())
1259 { 1373 {
1260 send = new dns_snd (this); 1374 send = new dns_snd (this);
1261 1375
1262 cfg.reset (THISNODE->id); 1376 cfg.reset (THISNODE->id);
1377 set_cfg ();
1263 send->gen_syn_req (); 1378 send->gen_syn_req ();
1264 } 1379 }
1265 } 1380 }
1266 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1381 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1267 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1382 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1268 { 1383 {
1269 if (last_sent + send_interval <= ev_now ()) 1384 if (last_sent + send_interval <= ev_now ())
1270 { 1385 {
1271 //printf ("sending data request etc.\n"); //D 1386 //printf ("sending data request etc.\n"); //D
1272 if (!snddq.empty () || last_received + 1. > ev_now ()) 1387 if (!snddq.empty ())
1273 {
1274 poll_interval = send_interval; 1388 min_it (next, send_interval);
1275 NEXT (ev_now () + send_interval);
1276 }
1277 1389
1278 send = new dns_snd (this); 1390 send = new dns_snd (this);
1279 send->gen_stream_req (sndseq, snddq); 1391 send->gen_stream_req (sndseq, snddq);
1280 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; 1392 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1281 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D 1393 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1282 1394
1283 sndseq = (sndseq + 1) & SEQNO_MASK; 1395 sndseq = (sndseq + 1) & SEQNO_MASK;
1284 } 1396 }
1285 else 1397 else
1286 NEXT (last_sent + send_interval); 1398 min_it (next, last_sent + send_interval - ev_now ());
1287 } 1399 }
1288 1400
1289 if (send) 1401 if (send)
1290 vpn->dns_sndpq.push_back (send); 1402 vpn->dns_sndpq.push_back (send);
1291 } 1403 }
… …
1296 sendto (vpn->dnsv4_fd, 1408 sendto (vpn->dnsv4_fd,
1297 send->pkt->at (0), send->pkt->len, 0, 1409 send->pkt->at (0), send->pkt->len, 0,
1298 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1410 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1299 } 1411 }
1300 1412
1413 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1414
1301 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1415 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1302 poll_interval, send_interval, next - ev_now (), 1416 poll_interval, send_interval, next - ev_now (),
1303 vpn->dns_sndpq.size (), snddq.size (), 1417 vpn->dns_sndpq.size (), snddq.size (),
1304 rcvpq.size ()); 1418 rcvpq.size ());
1305 1419
1306 // TODO: no idea when this happens, but when next < ev_now (), we have a problem 1420 w.start (next);
1307 // doesn't seem to happen anymore
1308 if (next < ev_now () + 0.001)
1309 next = ev_now () + 0.1;
1310
1311 w.start (next - ev_now ());
1312} 1421}
1313 1422
1314#endif 1423#endif
1315 1424

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