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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.40 by pcg, Sat Jul 9 20:29:29 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{
466 // although the protocol itself allows for some configurability, 528 // although the protocol itself allows for some configurability,
467 // only the following encoding/decoding settings are implemented. 529 // only the following encoding/decoding settings are implemented.
468 return id1 == 'G' 530 return id1 == 'G'
469 && id2 == 'V' 531 && id2 == 'V'
470 && id3 == 'P' 532 && id3 == 'P'
471 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
472 && seq_cdc == 26 535 && syn_cdc == 26
473 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
474 && rep_cdc == 0 538 && rep_cdc == 0
475 && version == 1; 539 && chksum == get_chksum ();
476} 540}
477 541
478struct dns_packet : net_packet 542struct dns_packet : net_packet
479{ 543{
480 u16 id; 544 u16 id;
… …
484 u8 data [MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
485 549
486 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
487}; 551};
488 552
553int
489int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
490{ 555{
491 char *orig = data; 556 char *orig = data;
492 557
493 memset (data, 0, size); 558 memset (data, 0, size);
494 559
… …
520 return data - orig; 585 return data - orig;
521} 586}
522 587
523///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
524 589
590static
591u16 next_id ()
592{
525static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
526 594
527static u16 next_id ()
528{
529 if (!dns_id) 595 if (!dns_id)
530 dns_id = time (0); 596 dns_id = time (0);
531 597
532 // the simplest lsfr with periodicity 65535 i could find 598 // the simplest lsfr with periodicity 65535 i could find
533 dns_id = (dns_id << 1) 599 dns_id = (dns_id << 1)
… …
548 struct vpn *vpn; 614 struct vpn *vpn;
549 615
550 dns_cfg cfg; 616 dns_cfg cfg;
551 617
552 bool established; 618 bool established;
619 const basecoder *cdc;
553 620
554 tstamp last_received; 621 tstamp last_received;
555 tstamp last_sent; 622 tstamp last_sent;
556 double min_latency; 623 double min_latency;
557 double poll_interval, send_interval; 624 double poll_interval, send_interval;
… …
559 vector<dns_rcv *> rcvpq; 626 vector<dns_rcv *> rcvpq;
560 627
561 byte_stream rcvdq; int rcvseq; int repseq; 628 byte_stream rcvdq; int rcvseq; int repseq;
562 byte_stream snddq; int sndseq; 629 byte_stream snddq; int sndseq;
563 630
564 void time_cb (time_watcher &w); time_watcher tw; 631 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
565 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
566 636
567 dns_connection (connection *c); 637 dns_connection (connection *c);
568 ~dns_connection (); 638 ~dns_connection ();
569}; 639};
570 640
… …
588: dns (dns) 658: dns (dns)
589{ 659{
590 timeout = 0; 660 timeout = 0;
591 retry = 0; 661 retry = 0;
592 seqno = 0; 662 seqno = 0;
593 sent = NOW; 663 sent = ev_now ();
594 stdhdr = false; 664 stdhdr = false;
595 665
596 pkt = new dns_packet; 666 pkt = new dns_packet;
597 667
598 pkt->id = next_id (); 668 pkt->id = next_id ();
… …
601dns_snd::~dns_snd () 671dns_snd::~dns_snd ()
602{ 672{
603 delete pkt; 673 delete pkt;
604} 674}
605 675
676static void
606static void append_domain (dns_packet &pkt, int &offs, const char *domain) 677append_domain (dns_packet &pkt, int &offs, const char *domain)
607{ 678{
608 // add tunnel domain 679 // add tunnel domain
609 for (;;) 680 for (;;)
610 { 681 {
611 const char *end = strchr (domain, '.'); 682 const char *end = strchr (domain, '.');
… …
624 695
625 domain = end + 1; 696 domain = end + 1;
626 } 697 }
627} 698}
628 699
700void
629void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 701dns_snd::gen_stream_req (int seqno, byte_stream &stream)
630{ 702{
631 stdhdr = true; 703 stdhdr = true;
632 this->seqno = seqno; 704 this->seqno = seqno;
633 705
634 timeout = NOW + INITIAL_TIMEOUT; 706 timeout = ev_now () + INITIAL_TIMEOUT;
635 707
636 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 708 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
637 pkt->qdcount = htons (1); 709 pkt->qdcount = htons (1);
638 710
639 int offs = 6*2; 711 int offs = 6*2;
… …
642 // 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
643 715
644 char enc[256], *encp = enc; 716 char enc[256], *encp = enc;
645 encode_header (enc, THISNODE->id, seqno); 717 encode_header (enc, THISNODE->id, seqno);
646 718
647 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);
648 720
649 if (datalen > stream.size ()) 721 if (datalen > stream.size ())
650 datalen = stream.size (); 722 datalen = stream.size ();
651 723
652 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 724 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
653 stream.remove (datalen); 725 stream.remove (datalen);
654 726
655 while (enclen) 727 while (enclen)
656 { 728 {
657 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 729 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
672 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 744 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
673 745
674 pkt->len = offs; 746 pkt->len = offs;
675} 747}
676 748
749void
677void dns_snd::gen_syn_req () 750dns_snd::gen_syn_req ()
678{ 751{
679 timeout = NOW + INITIAL_SYN_TIMEOUT; 752 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
680 753
681 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 754 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
682 pkt->qdcount = htons (1); 755 pkt->qdcount = htons (1);
683 756
684 int offs = 6 * 2; 757 int offs = 6 * 2;
… …
724 797
725dns_connection::dns_connection (connection *c) 798dns_connection::dns_connection (connection *c)
726: c (c) 799: c (c)
727, rcvdq (MAX_BACKLOG * 2) 800, rcvdq (MAX_BACKLOG * 2)
728, snddq (MAX_BACKLOG) 801, snddq (MAX_BACKLOG)
729, tw (this, &dns_connection::time_cb)
730{ 802{
803 tw.set<dns_connection, &dns_connection::time_cb> (this);
804
731 vpn = c->vpn; 805 vpn = c->vpn;
732 806
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
733 established = false; 831 established = false;
734 832
735 rcvseq = repseq = sndseq = 0; 833 rcvseq = repseq = sndseq = 0;
736 834
737 last_sent = last_received = 0; 835 last_sent = 0;
738 poll_interval = 0.5; // starting here 836 poll_interval = 0.5; // starting here
739 send_interval = 0.5; // starting rate 837 send_interval = 0.5; // starting rate
740 min_latency = INITIAL_TIMEOUT; 838 min_latency = INITIAL_TIMEOUT;
741} 839}
742 840
743dns_connection::~dns_connection () 841void
842dns_connection::set_cfg ()
744{ 843{
745 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 844 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
746 i != rcvpq.end ();
747 ++i)
748 delete *i;
749} 845}
750 846
847void
751void dns_connection::receive_rep (dns_rcv *r) 848dns_connection::receive_rep (dns_rcv *r)
752{ 849{
753 if (r->datalen) 850 if (r->datalen)
754 { 851 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
755 last_received = NOW;
756 tw.trigger ();
757
758 poll_interval = send_interval;
759 }
760 else 852 else
761 { 853 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
762 poll_interval *= 1.5;
763
764 if (poll_interval > MAX_POLL_INTERVAL)
765 poll_interval = MAX_POLL_INTERVAL;
766 }
767 854
768 rcvpq.push_back (r); 855 rcvpq.push_back (r);
769 856
770 redo: 857 redo:
771 858
772 // find next packet 859 // find next packet
773 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 860 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
774 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 861 if (SEQNO_EQ (rcvseq, (*i)->seqno))
775 { 862 {
863 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
776 // enter the packet into our input stream 864 // enter the packet into our input stream
777 r = *i; 865 r = *i;
778 866
779 // remove the oldest packet, look forward, as it's oldest first 867 // remove the oldest packet, look forward, as it's oldest first
780 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)
781 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 869 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
782 { 870 {
871 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
783 delete *j; 872 delete *j;
784 rcvpq.erase (j); 873 rcvpq.erase (j);
785 break; 874 break;
786 } 875 }
787 876
788 rcvseq = (rcvseq + 1) & SEQNO_MASK; 877 rcvseq = (rcvseq + 1) & SEQNO_MASK;
789 878
790 if (!rcvdq.put (r->data, r->datalen)) 879 if (!rcvdq.put (r->data, r->datalen))
791 { 880 {
881 // MUST never overflow, can be caused by data corruption, TODO
792 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 882 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
793 abort (); // MUST never overflow, can be caused by data corruption, TODO 883 reset ();
884 return;
794 } 885 }
795 886
796 while (vpn_packet *pkt = rcvdq.get ()) 887 while (vpn_packet *pkt = rcvdq.get ())
797 { 888 {
798 sockinfo si; 889 sockinfo si;
799 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;
800 891
801 vpn->recv_vpn_packet (pkt, si); 892 vpn->recv_vpn_packet (pkt, si);
802
803 delete pkt; 893 delete pkt;
804 } 894 }
805 895
806 // check for further packets 896 // check for further packets
807 goto redo; 897 goto redo;
… …
850 { 940 {
851 // correct class, domain: parse 941 // correct class, domain: parse
852 int client, seqno; 942 int client, seqno;
853 decode_header (qname, client, seqno); 943 decode_header (qname, client, seqno);
854 944
855 u8 data[MAXSIZE];
856 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
857
858 if (0 < client && client <= conns.size ()) 945 if (0 < client && client <= conns.size ())
859 { 946 {
860 connection *c = conns [client - 1]; 947 connection *c = conns [client - 1];
861 dns_connection *dns = c->dns; 948 dns_connection *dns = c->dns;
862 dns_rcv *rcv; 949 dns_rcv *rcv;
863 950
864 if (dns) 951 if (dns)
865 { 952 {
953 u8 data[MAXSIZE];
954 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
955
866 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 (); )
867 if (SEQNO_EQ ((*i)->seqno, seqno)) 957 if (SEQNO_EQ ((*i)->seqno, seqno))
868 { 958 {
869 // already seen that request: simply reply with the cached reply 959 // already seen that request: simply reply with the cached reply
870 dns_rcv *r = *i; 960 dns_rcv *r = *i;
… …
971 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
972 pkt [offs++] = 0; pkt [offs++] = 0; 1062 pkt [offs++] = 0; pkt [offs++] = 0;
973 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1063 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
974 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1064 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
975 1065
976 slog (L_INFO, _("DNS: client %d connects"), client);
977
978 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;
979 pkt [offs++] = CMD_IP_REJ; 1067 pkt [offs++] = CMD_IP_REJ;
980 1068
981 if (0 < client && client <= conns.size ()) 1069 if (0 < client && client <= conns.size ())
982 { 1070 {
983 connection *c = conns [client - 1]; 1071 connection *c = conns [client - 1];
984 1072
985 if (cfg.valid ()) 1073 if (cfg.valid ())
986 { 1074 {
987 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));
988 1080
989 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
990 c->dns = new dns_connection (c); 1086 c->dns = new dns_connection (c);
991 c->dns->cfg = cfg; 1087 c->dns->cfg = cfg;
1088 c->dns->set_cfg ();
992 } 1089 }
993 } 1090 }
994 } 1091 }
995 } 1092 }
996 1093
… …
1015 { 1112 {
1016 dns_connection *dns = (*i)->dns; 1113 dns_connection *dns = (*i)->dns;
1017 connection *c = dns->c; 1114 connection *c = dns->c;
1018 int seqno = (*i)->seqno; 1115 int seqno = (*i)->seqno;
1019 u8 data[MAXSIZE], *datap = data; 1116 u8 data[MAXSIZE], *datap = data;
1117 //printf ("rcv pkt %x\n", seqno);//D
1020 1118
1021 if ((*i)->retry) 1119 if ((*i)->retry)
1022 { 1120 {
1023 dns->send_interval *= 1.01; 1121 dns->send_interval *= 1.01;
1024 if (dns->send_interval > MAX_SEND_INTERVAL) 1122 if (dns->send_interval > MAX_SEND_INTERVAL)
… …
1029#if 0 1127#if 0
1030 dns->send_interval *= 0.999; 1128 dns->send_interval *= 0.999;
1031#endif 1129#endif
1032 // the latency surely puts an upper bound on 1130 // the latency surely puts an upper bound on
1033 // the minimum send interval 1131 // the minimum send interval
1034 double latency = NOW - (*i)->sent; 1132 double latency = ev_now () - (*i)->sent;
1035 1133
1036 if (latency < dns->min_latency) 1134 if (latency < dns->min_latency)
1037 dns->min_latency = latency; 1135 dns->min_latency = latency;
1038 1136
1039 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) 1137 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
… …
1066 ttl |= pkt [offs++] << 16; 1164 ttl |= pkt [offs++] << 16;
1067 ttl |= pkt [offs++] << 8; 1165 ttl |= pkt [offs++] << 8;
1068 ttl |= pkt [offs++]; 1166 ttl |= pkt [offs++];
1069 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1167 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1070 1168
1071 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1169 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1072 { 1170 {
1073 if (rdlen <= MAXSIZE - offs) 1171 if (rdlen <= MAXSIZE - offs)
1074 { 1172 {
1075 // decode bytes, finally 1173 // decode bytes, finally
1076 1174
… …
1102 { 1200 {
1103 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1201 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1104 1202
1105 if (ip [3] == CMD_IP_RST) 1203 if (ip [3] == CMD_IP_RST)
1106 { 1204 {
1107 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1205 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1108 1206
1109 delete dns; c->dns = 0; 1207 dns->reset ();
1110
1111 return; 1208 return;
1112 } 1209 }
1113 else if (ip [3] == CMD_IP_SYN) 1210 else if (ip [3] == CMD_IP_SYN)
1114 { 1211 {
1115 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1212 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1116 dns->established = true; 1213 dns->established = true;
1117 } 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 }
1118 else if (ip [3] == CMD_IP_REJ) 1230 else if (ip [3] == CMD_IP_REJ)
1119 { 1231 {
1120 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."));
1121 abort (); 1233 dns->tw.start (60.);
1122 } 1234 }
1123 else 1235 else
1236 {
1124 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 }
1125 } 1240 }
1126 else 1241 else
1127 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"),
1128 ip [0], ip [1], ip [2], ip [3]); 1243 ip [0], ip [1], ip [2], ip [3]);
1129 1244
… …
1153 break; 1268 break;
1154 } 1269 }
1155} 1270}
1156 1271
1157void 1272void
1158vpn::dnsv4_ev (io_watcher &w, short revents) 1273vpn::dnsv4_ev (ev::io &w, int revents)
1159{ 1274{
1160 if (revents & EVENT_READ) 1275 if (revents & EV_READ)
1161 { 1276 {
1162 dns_packet *pkt = new dns_packet; 1277 dns_packet *pkt = new dns_packet;
1163 struct sockaddr_in sa; 1278 struct sockaddr_in sa;
1164 socklen_t sa_len = sizeof (sa); 1279 socklen_t sa_len = sizeof (sa);
1165 1280
… …
1191 1306
1192 if (!c->dns) 1307 if (!c->dns)
1193 c->dns = new dns_connection (c); 1308 c->dns = new dns_connection (c);
1194 1309
1195 if (c->dns->snddq.put (pkt)) 1310 if (c->dns->snddq.put (pkt))
1311 {
1312 min_it (c->dns->poll_interval, 0.25);
1196 c->dns->tw.trigger (); 1313 c->dns->tw ();
1314 }
1197 1315
1198 // always return true even if the buffer overflows 1316 // always return true even if the buffer overflows
1199 return true; 1317 return true;
1200} 1318}
1201 1319
1202void 1320void
1203connection::dnsv4_reset_connection () 1321dns_connection::time_cb (ev::timer &w, int revents)
1204{
1205 //delete dns; dns = 0; //TODO
1206}
1207
1208#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1209
1210void
1211dns_connection::time_cb (time_watcher &w)
1212{ 1322{
1213 // servers have to be polled 1323 // servers have to be polled
1214 if (THISNODE->dns_port) 1324 if (THISNODE->dns_port)
1215 return; 1325 return;
1216 1326
1217 // check for timeouts and (re)transmit 1327 // check for timeouts and (re)transmit
1218 tstamp next = NOW + poll_interval; 1328 tstamp next = 86400 * 365;
1219 dns_snd *send = 0; 1329 dns_snd *send = 0;
1220 1330
1221 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1331 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1222 i != vpn->dns_sndpq.end (); 1332 i != vpn->dns_sndpq.end ();
1223 ++i) 1333 ++i)
1224 { 1334 {
1225 dns_snd *r = *i; 1335 dns_snd *r = *i;
1226 1336
1227 if (r->timeout <= NOW) 1337 if (r->timeout <= ev_now ())
1228 { 1338 {
1229 if (!send) 1339 if (!send)
1230 { 1340 {
1231 send = r; 1341 send = r;
1232 1342
1233 r->retry++; 1343 r->retry++;
1234 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
1235 1346
1236 // the following code changes the query section a bit, forcing 1347 // the following code changes the query section a bit, forcing
1237 // the forwarder to generate a new request 1348 // the forwarder to generate a new request
1238 if (r->stdhdr) 1349 if (r->stdhdr)
1239 {
1240 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1241 //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);
1242 }
1243 } 1351 }
1244 } 1352 }
1245 else 1353 else
1246 NEXT (r->timeout); 1354 min_it (next, r->timeout - ev_now ());
1247 } 1355 }
1248 1356
1249 if (!send) 1357 if (!send)
1250 { 1358 {
1251 // generate a new packet, if wise 1359 // generate a new packet, if wise
… …
1255 if (vpn->dns_sndpq.empty ()) 1363 if (vpn->dns_sndpq.empty ())
1256 { 1364 {
1257 send = new dns_snd (this); 1365 send = new dns_snd (this);
1258 1366
1259 cfg.reset (THISNODE->id); 1367 cfg.reset (THISNODE->id);
1368 set_cfg ();
1260 send->gen_syn_req (); 1369 send->gen_syn_req ();
1261 } 1370 }
1262 } 1371 }
1263 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1372 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1264 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1373 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1265 { 1374 {
1266 if (last_sent + send_interval <= NOW) 1375 if (last_sent + send_interval <= ev_now ())
1267 { 1376 {
1268 //printf ("sending data request etc.\n"); //D 1377 //printf ("sending data request etc.\n"); //D
1269 if (!snddq.empty () || last_received + 1. > NOW) 1378 if (!snddq.empty ())
1270 {
1271 poll_interval = send_interval;
1272 NEXT (NOW + send_interval); 1379 min_it (next, send_interval);
1273 }
1274 1380
1275 send = new dns_snd (this); 1381 send = new dns_snd (this);
1276 send->gen_stream_req (sndseq, snddq); 1382 send->gen_stream_req (sndseq, snddq);
1277 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
1278 1385
1279 sndseq = (sndseq + 1) & SEQNO_MASK; 1386 sndseq = (sndseq + 1) & SEQNO_MASK;
1280 } 1387 }
1281 else 1388 else
1282 NEXT (last_sent + send_interval); 1389 min_it (next, last_sent + send_interval - ev_now ());
1283 } 1390 }
1284 1391
1285 if (send) 1392 if (send)
1286 vpn->dns_sndpq.push_back (send); 1393 vpn->dns_sndpq.push_back (send);
1287 } 1394 }
1288 1395
1289 if (send) 1396 if (send)
1290 { 1397 {
1291 last_sent = NOW; 1398 last_sent = ev_now ();
1292 sendto (vpn->dnsv4_fd, 1399 sendto (vpn->dnsv4_fd,
1293 send->pkt->at (0), send->pkt->len, 0, 1400 send->pkt->at (0), send->pkt->len, 0,
1294 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1401 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1295 } 1402 }
1296 1403
1404 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1405
1297 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)",
1298 poll_interval, send_interval, next - NOW, 1407 poll_interval, send_interval, next - ev_now (),
1299 vpn->dns_sndpq.size (), snddq.size (), 1408 vpn->dns_sndpq.size (), snddq.size (),
1300 rcvpq.size ()); 1409 rcvpq.size ());
1301 1410
1302 // TODO: no idea when this happens, but when next < NOW, we have a problem
1303 // doesn't seem to happen anymore
1304 if (next < NOW + 0.001)
1305 next = NOW + 0.1;
1306
1307 w.start (next); 1411 w.start (next);
1308} 1412}
1309 1413
1310#endif 1414#endif
1311 1415

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