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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 1.53 by root, Tue Oct 18 10:54:17 2011 UTC

1/* 1/*
2 vpn_dns.C -- handle the dns tunnel part of the protocol. 2 vpn_dns.C -- handle the dns tunnel part of the protocol.
3 Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de> 3 Copyright (C) 2003-2011 Marc Lehmann <gvpe@schmorp.de>
4 4
5 This file is part of GVPE. 5 This file is part of GVPE.
6 6
7 GVPE is free software; you can redistribute it and/or modify 7 GVPE is free software; you can redistribute it and/or modify it
8 it under the terms of the GNU General Public License as published by 8 under the terms of the GNU General Public License as published by the
9 the Free Software Foundation; either version 2 of the License, or 9 Free Software Foundation; either version 3 of the License, or (at your
10 (at your option) any later version. 10 option) any later version.
11 11
12 This program is distributed in the hope that it will be useful, 12 This program is distributed in the hope that it will be useful, but
13 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15 GNU General Public License for more details. 15 Public License for more details.
16 16
17 You should have received a copy of the GNU General Public License 17 You should have received a copy of the GNU General Public License along
18 along with gvpe; if not, write to the Free Software 18 with this program; if not, see <http://www.gnu.org/licenses/>.
19 Foundation, Inc. 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;
… …
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{
467 // although the protocol itself allows for some configurability, 528 // although the protocol itself allows for some configurability,
468 // only the following encoding/decoding settings are implemented. 529 // only the following encoding/decoding settings are implemented.
469 return id1 == 'G' 530 return id1 == 'G'
470 && id2 == 'V' 531 && id2 == 'V'
471 && id3 == 'P' 532 && id3 == 'P'
472 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
473 && seq_cdc == 26 535 && syn_cdc == 26
474 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
475 && rep_cdc == 0 538 && rep_cdc == 0
476 && version == 1; 539 && chksum == get_chksum ();
477} 540}
478 541
479struct dns_packet : net_packet 542struct dns_packet : net_packet
480{ 543{
481 u16 id; 544 u16 id;
… …
485 u8 data [MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
486 549
487 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
488}; 551};
489 552
553int
490int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
491{ 555{
492 char *orig = data; 556 char *orig = data;
493 557
494 memset (data, 0, size); 558 memset (data, 0, size);
495 559
… …
521 return data - orig; 585 return data - orig;
522} 586}
523 587
524///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
525 589
590static
591u16 next_id ()
592{
526static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
527 594
528static u16 next_id () 595#if 1
529{
530 if (!dns_id) 596 if (!dns_id)
531 dns_id = time (0); 597 dns_id = time (0);
532 598
533 // the simplest lsfr with periodicity 65535 i could find 599 // the simplest lsfr with periodicity 65535 i could find
534 dns_id = (dns_id << 1) 600 dns_id = (dns_id << 1)
… …
536 ^ (dns_id >> 2) 602 ^ (dns_id >> 2)
537 ^ (dns_id >> 4) 603 ^ (dns_id >> 4)
538 ^ (dns_id >> 15)) & 1); 604 ^ (dns_id >> 15)) & 1);
539 605
540 return dns_id; 606 return dns_id;
607#else
608 dns_id++;//D
609
610 return htons (dns_id);
611#endif
541} 612}
542 613
543struct dns_rcv; 614struct dns_rcv;
544struct dns_snd; 615struct dns_snd;
545 616
… …
549 struct vpn *vpn; 620 struct vpn *vpn;
550 621
551 dns_cfg cfg; 622 dns_cfg cfg;
552 623
553 bool established; 624 bool established;
625 const basecoder *cdc;
554 626
555 tstamp last_received; 627 tstamp last_received;
556 tstamp last_sent; 628 tstamp last_sent;
557 double min_latency; 629 double min_latency;
558 double poll_interval, send_interval; 630 double poll_interval, send_interval;
… …
560 vector<dns_rcv *> rcvpq; 632 vector<dns_rcv *> rcvpq;
561 633
562 byte_stream rcvdq; int rcvseq; int repseq; 634 byte_stream rcvdq; int rcvseq; int repseq;
563 byte_stream snddq; int sndseq; 635 byte_stream snddq; int sndseq;
564 636
565 void time_cb (ev::timer &w, int revents); ev::timer tw; 637 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
566 void receive_rep (dns_rcv *r); 638 void receive_rep (dns_rcv *r);
639
640 void reset (); // quite like tcp RST
641 void set_cfg (); // to be called after any cfg changes
567 642
568 dns_connection (connection *c); 643 dns_connection (connection *c);
569 ~dns_connection (); 644 ~dns_connection ();
570}; 645};
571 646
… …
602dns_snd::~dns_snd () 677dns_snd::~dns_snd ()
603{ 678{
604 delete pkt; 679 delete pkt;
605} 680}
606 681
682static void
607static void append_domain (dns_packet &pkt, int &offs, const char *domain) 683append_domain (dns_packet &pkt, int &offs, const char *domain)
608{ 684{
609 // add tunnel domain 685 // add tunnel domain
610 for (;;) 686 for (;;)
611 { 687 {
612 const char *end = strchr (domain, '.'); 688 const char *end = strchr (domain, '.');
… …
625 701
626 domain = end + 1; 702 domain = end + 1;
627 } 703 }
628} 704}
629 705
706void
630void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 707dns_snd::gen_stream_req (int seqno, byte_stream &stream)
631{ 708{
632 stdhdr = true; 709 stdhdr = true;
633 this->seqno = seqno; 710 this->seqno = seqno;
634 711
635 timeout = ev_now () + INITIAL_TIMEOUT; 712 timeout = ev_now () + INITIAL_TIMEOUT;
… …
643 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 720 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
644 721
645 char enc[256], *encp = enc; 722 char enc[256], *encp = enc;
646 encode_header (enc, THISNODE->id, seqno); 723 encode_header (enc, THISNODE->id, seqno);
647 724
648 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 725 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
649 726
650 if (datalen > stream.size ()) 727 if (datalen > stream.size ())
651 datalen = stream.size (); 728 datalen = stream.size ();
652 729
653 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 730 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
654 stream.remove (datalen); 731 stream.remove (datalen);
655 732
656 while (enclen) 733 while (enclen)
657 { 734 {
658 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 735 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
673 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 750 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
674 751
675 pkt->len = offs; 752 pkt->len = offs;
676} 753}
677 754
755void
678void dns_snd::gen_syn_req () 756dns_snd::gen_syn_req ()
679{ 757{
680 timeout = ev_now () + INITIAL_SYN_TIMEOUT; 758 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
681 759
682 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 760 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
683 pkt->qdcount = htons (1); 761 pkt->qdcount = htons (1);
… …
730{ 808{
731 tw.set<dns_connection, &dns_connection::time_cb> (this); 809 tw.set<dns_connection, &dns_connection::time_cb> (this);
732 810
733 vpn = c->vpn; 811 vpn = c->vpn;
734 812
813 reset ();
814}
815
816dns_connection::~dns_connection ()
817{
818 reset ();
819}
820
821void
822dns_connection::reset ()
823{
824 while (!rcvpq.empty ())
825 {
826 delete rcvpq.back ();
827 rcvpq.pop_back ();
828 }
829
830 for (int i = vpn->dns_sndpq.size (); i--; )
831 if (vpn->dns_sndpq [i]->dns == this)
832 {
833 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
834 vpn->dns_sndpq.pop_back ();
835 }
836
735 established = false; 837 established = false;
736 838
737 rcvseq = repseq = sndseq = 0; 839 rcvseq = repseq = sndseq = 0;
738 840
739 last_sent = last_received = 0; 841 last_sent = 0;
740 poll_interval = 0.5; // starting here 842 poll_interval = 0.5; // starting here
741 send_interval = 0.5; // starting rate 843 send_interval = 0.5; // starting rate
742 min_latency = INITIAL_TIMEOUT; 844 min_latency = INITIAL_TIMEOUT;
743} 845}
744 846
745dns_connection::~dns_connection () 847void
848dns_connection::set_cfg ()
746{ 849{
747 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 850 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
748 i != rcvpq.end ();
749 ++i)
750 delete *i;
751} 851}
752 852
853void
753void dns_connection::receive_rep (dns_rcv *r) 854dns_connection::receive_rep (dns_rcv *r)
754{ 855{
755 if (r->datalen) 856 if (r->datalen)
756 { 857 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 858 else
763 { 859 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 }
769 860
770 rcvpq.push_back (r); 861 rcvpq.push_back (r);
771 862
772 redo: 863 redo:
773 864
… …
791 882
792 rcvseq = (rcvseq + 1) & SEQNO_MASK; 883 rcvseq = (rcvseq + 1) & SEQNO_MASK;
793 884
794 if (!rcvdq.put (r->data, r->datalen)) 885 if (!rcvdq.put (r->data, r->datalen))
795 { 886 {
887 // MUST never overflow, can be caused by data corruption, TODO
796 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 888 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
797 abort (); // MUST never overflow, can be caused by data corruption, TODO 889 reset ();
890 return;
798 } 891 }
799 892
800 while (vpn_packet *pkt = rcvdq.get ()) 893 while (vpn_packet *pkt = rcvdq.get ())
801 { 894 {
802 sockinfo si; 895 sockinfo si;
803 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; 896 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
804 897
805 vpn->recv_vpn_packet (pkt, si); 898 vpn->recv_vpn_packet (pkt, si);
806
807 delete pkt; 899 delete pkt;
808 } 900 }
809 901
810 // check for further packets 902 // check for further packets
811 goto redo; 903 goto redo;
… …
854 { 946 {
855 // correct class, domain: parse 947 // correct class, domain: parse
856 int client, seqno; 948 int client, seqno;
857 decode_header (qname, client, seqno); 949 decode_header (qname, client, seqno);
858 950
859 u8 data[MAXSIZE];
860 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
861
862 if (0 < client && client <= conns.size ()) 951 if (0 < client && client <= conns.size ())
863 { 952 {
864 connection *c = conns [client - 1]; 953 connection *c = conns [client - 1];
865 dns_connection *dns = c->dns; 954 dns_connection *dns = c->dns;
866 dns_rcv *rcv; 955 dns_rcv *rcv;
867 956
868 if (dns) 957 if (dns)
869 { 958 {
959 u8 data[MAXSIZE];
960 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
961
870 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 962 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
871 if (SEQNO_EQ ((*i)->seqno, seqno)) 963 if (SEQNO_EQ ((*i)->seqno, seqno))
872 { 964 {
873 // already seen that request: simply reply with the cached reply 965 // already seen that request: simply reply with the cached reply
874 dns_rcv *r = *i; 966 dns_rcv *r = *i;
… …
975 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1067 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
976 pkt [offs++] = 0; pkt [offs++] = 0; 1068 pkt [offs++] = 0; pkt [offs++] = 0;
977 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1069 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
978 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1070 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
979 1071
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; 1072 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
983 pkt [offs++] = CMD_IP_REJ; 1073 pkt [offs++] = CMD_IP_REJ;
984 1074
985 if (0 < client && client <= conns.size ()) 1075 if (0 < client && client <= conns.size ())
986 { 1076 {
987 connection *c = conns [client - 1]; 1077 connection *c = conns [client - 1];
988 1078
989 if (cfg.valid ()) 1079 if (cfg.valid ())
990 { 1080 {
991 pkt [offs - 1] = CMD_IP_SYN; 1081 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1082
1083 // check for any encoding mismatches - hints at a case problem
1084 char qname2 [MAX_ENC_LEN];
1085 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
992 1086
993 delete c->dns; 1087 delete c->dns;
1088
1089 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1090 ? CMD_IP_CSE : CMD_IP_SYN;
1091
994 c->dns = new dns_connection (c); 1092 c->dns = new dns_connection (c);
995 c->dns->cfg = cfg; 1093 c->dns->cfg = cfg;
1094 c->dns->set_cfg ();
996 } 1095 }
997 } 1096 }
998 } 1097 }
999 } 1098 }
1000 1099
… …
1071 ttl |= pkt [offs++] << 16; 1170 ttl |= pkt [offs++] << 16;
1072 ttl |= pkt [offs++] << 8; 1171 ttl |= pkt [offs++] << 8;
1073 ttl |= pkt [offs++]; 1172 ttl |= pkt [offs++];
1074 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1173 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1075 1174
1076 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1175 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1077 { 1176 {
1078 if (rdlen <= MAXSIZE - offs) 1177 if (rdlen <= MAXSIZE - offs)
1079 { 1178 {
1080 // decode bytes, finally 1179 // decode bytes, finally
1081 1180
… …
1107 { 1206 {
1108 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1207 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1109 1208
1110 if (ip [3] == CMD_IP_RST) 1209 if (ip [3] == CMD_IP_RST)
1111 { 1210 {
1112 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1211 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1113 1212
1114 delete dns; c->dns = 0; 1213 dns->reset ();
1115
1116 return; 1214 return;
1117 } 1215 }
1118 else if (ip [3] == CMD_IP_SYN) 1216 else if (ip [3] == CMD_IP_SYN)
1119 { 1217 {
1120 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1218 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1121 dns->established = true; 1219 dns->established = true;
1122 } 1220 }
1221 else if (ip [3] == CMD_IP_CSE)
1222 {
1223 if (conf.dns_case_preserving)
1224 {
1225 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1226 conf.dns_case_preserving = false;
1227 dns->reset ();
1228 return;
1229 }
1230 else
1231 {
1232 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1233 dns->established = true;
1234 }
1235 }
1123 else if (ip [3] == CMD_IP_REJ) 1236 else if (ip [3] == CMD_IP_REJ)
1124 { 1237 {
1125 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1238 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1126 abort (); 1239 dns->tw.start (60.);
1127 } 1240 }
1128 else 1241 else
1242 {
1129 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1243 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1244 dns->tw.start (60.);
1245 }
1130 } 1246 }
1131 else 1247 else
1132 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1248 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1133 ip [0], ip [1], ip [2], ip [3]); 1249 ip [0], ip [1], ip [2], ip [3]);
1134 1250
… …
1196 1312
1197 if (!c->dns) 1313 if (!c->dns)
1198 c->dns = new dns_connection (c); 1314 c->dns = new dns_connection (c);
1199 1315
1200 if (c->dns->snddq.put (pkt)) 1316 if (c->dns->snddq.put (pkt))
1317 {
1318 min_it (c->dns->poll_interval, 0.25);
1201 c->dns->tw (); 1319 c->dns->tw ();
1320 }
1202 1321
1203 // always return true even if the buffer overflows 1322 // always return true even if the buffer overflows
1204 return true; 1323 return true;
1205} 1324}
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 1325
1215void 1326void
1216dns_connection::time_cb (ev::timer &w, int revents) 1327dns_connection::time_cb (ev::timer &w, int revents)
1217{ 1328{
1218 // servers have to be polled 1329 // servers have to be polled
1219 if (THISNODE->dns_port) 1330 if (THISNODE->dns_port)
1220 return; 1331 return;
1221 1332
1222 // check for timeouts and (re)transmit 1333 // check for timeouts and (re)transmit
1223 tstamp next = ev::now () + poll_interval; 1334 tstamp next = 86400 * 365;
1224 dns_snd *send = 0; 1335 dns_snd *send = 0;
1225 1336
1226 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1337 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1227 i != vpn->dns_sndpq.end (); 1338 i != vpn->dns_sndpq.end ();
1228 ++i) 1339 ++i)
… …
1234 if (!send) 1345 if (!send)
1235 { 1346 {
1236 send = r; 1347 send = r;
1237 1348
1238 r->retry++; 1349 r->retry++;
1239 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); 1350 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 1351 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1241 1352
1242 // the following code changes the query section a bit, forcing 1353 // the following code changes the query section a bit, forcing
1243 // the forwarder to generate a new request 1354 // the forwarder to generate a new request
1244 if (r->stdhdr) 1355 if (r->stdhdr)
1245 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1356 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1246 } 1357 }
1247 } 1358 }
1248 else 1359 else
1249 NEXT (r->timeout); 1360 min_it (next, r->timeout - ev_now ());
1250 } 1361 }
1251 1362
1252 if (!send) 1363 if (!send)
1253 { 1364 {
1254 // generate a new packet, if wise 1365 // generate a new packet, if wise
… …
1258 if (vpn->dns_sndpq.empty ()) 1369 if (vpn->dns_sndpq.empty ())
1259 { 1370 {
1260 send = new dns_snd (this); 1371 send = new dns_snd (this);
1261 1372
1262 cfg.reset (THISNODE->id); 1373 cfg.reset (THISNODE->id);
1374 set_cfg ();
1263 send->gen_syn_req (); 1375 send->gen_syn_req ();
1264 } 1376 }
1265 } 1377 }
1266 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1378 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1267 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1379 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1268 { 1380 {
1269 if (last_sent + send_interval <= ev_now ()) 1381 if (last_sent + send_interval <= ev_now ())
1270 { 1382 {
1271 //printf ("sending data request etc.\n"); //D 1383 //printf ("sending data request etc.\n"); //D
1272 if (!snddq.empty () || last_received + 1. > ev_now ()) 1384 if (!snddq.empty ())
1273 {
1274 poll_interval = send_interval; 1385 min_it (next, send_interval);
1275 NEXT (ev_now () + send_interval);
1276 }
1277 1386
1278 send = new dns_snd (this); 1387 send = new dns_snd (this);
1279 send->gen_stream_req (sndseq, snddq); 1388 send->gen_stream_req (sndseq, snddq);
1280 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; 1389 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 1390 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1282 1391
1283 sndseq = (sndseq + 1) & SEQNO_MASK; 1392 sndseq = (sndseq + 1) & SEQNO_MASK;
1284 } 1393 }
1285 else 1394 else
1286 NEXT (last_sent + send_interval); 1395 min_it (next, last_sent + send_interval - ev_now ());
1287 } 1396 }
1288 1397
1289 if (send) 1398 if (send)
1290 vpn->dns_sndpq.push_back (send); 1399 vpn->dns_sndpq.push_back (send);
1291 } 1400 }
… …
1296 sendto (vpn->dnsv4_fd, 1405 sendto (vpn->dnsv4_fd,
1297 send->pkt->at (0), send->pkt->len, 0, 1406 send->pkt->at (0), send->pkt->len, 0,
1298 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1407 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1299 } 1408 }
1300 1409
1410 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1411
1301 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1412 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1302 poll_interval, send_interval, next - ev_now (), 1413 poll_interval, send_interval, next - ev_now (),
1303 vpn->dns_sndpq.size (), snddq.size (), 1414 vpn->dns_sndpq.size (), snddq.size (),
1304 rcvpq.size ()); 1415 rcvpq.size ());
1305 1416
1306 // TODO: no idea when this happens, but when next < ev_now (), we have a problem 1417 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} 1418}
1313 1419
1314#endif 1420#endif
1315 1421

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