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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.18 by pcg, Sat Mar 5 19:13:16 2005 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. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19
20 Additional permission under GNU GPL version 3 section 7
21
22 If you modify this Program, or any covered work, by linking or
23 combining it with the OpenSSL project's OpenSSL library (or a modified
24 version of that library), containing parts covered by the terms of the
25 OpenSSL or SSLeay licenses, the licensors of this Program grant you
26 additional permission to convey the resulting work. Corresponding
27 Source for a non-source form of such a combination shall include the
28 source code for the parts of OpenSSL used as well as that of the
29 covered work.
20*/ 30*/
31
32// TODO: EDNS0 option to increase dns mtu?
33// TODO: re-write dns packet parsing/creation using a safe mem-buffer
34// to ensure no buffer overflows or similar problems.
21 35
22#include "config.h" 36#include "config.h"
23 37
24#if ENABLE_DNS 38#if ENABLE_DNS
25 39
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 40// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27// it's a hack, use only in emergency situations please. 41// it's a hack, use only in emergency situations please.
28 42
29#include <cstring> 43#include <cstring>
44#include <cassert>
30 45
31#include <sys/types.h> 46#include <sys/types.h>
32#include <sys/socket.h> 47#include <sys/socket.h>
33#include <sys/wait.h> 48#include <sys/wait.h>
34#include <sys/uio.h> 49#include <sys/uio.h>
… …
37#include <unistd.h> 52#include <unistd.h>
38#include <fcntl.h> 53#include <fcntl.h>
39 54
40#include <map> 55#include <map>
41 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
42#include <gmp.h> 58#include <gmp.h>
43 59
44#include "netcompat.h" 60#include "netcompat.h"
45 61
46#include "vpn.h" 62#include "vpn.h"
47 63
48#define MIN_POLL_INTERVAL .02 // how often to poll minimally when the server has data 64#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received
49#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data 65#define MAX_POLL_INTERVAL 1. // how often to poll minimally when the server has no data
50#define ACTIVITY_INTERVAL 5.
51 66
52#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
53#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54 69
55#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
56#define MAX_SEND_INTERVAL 0.5 // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
57 71
58#define MAX_OUTSTANDING 10 // max. outstanding requests
59#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
60#define MAX_BACKLOG (100*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
61 74
62#define MAX_DOMAIN_SIZE 220 // 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
63// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
64// every two request bytes less give room for one reply byte 77// every request byte less give room for two reply bytes
65 78
66#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
67#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
68 81
69#define MAX_LBL_SIZE 63 82#define MAX_LBL_SIZE 63
70#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
71 84
72#define RR_TYPE_A 1 85#define RR_TYPE_A 1
73#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
74#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
75#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
76 90
77#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
78 92
79#define CMD_IP_1 207 93#define CMD_IP_1 207
80#define CMD_IP_2 46 94#define CMD_IP_2 46
81#define CMD_IP_3 236 95#define CMD_IP_3 236
82#define CMD_IP_RST 29 96
83#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
84#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}
85 113
86// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
87struct charmap 115struct charmap
88{ 116{
89 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
103 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
104 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
105 133
106 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
107 { 135 {
136 char c = cmap [size];
137
108 enc [size] = cmap [size]; 138 enc [size] = c;
109 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;
110 } 144 }
111 145
112 assert (size < 256); 146 assert (size < 256);
113} 147}
114 148
… …
121{ 155{
122 charmap cmap; 156 charmap cmap;
123 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
124 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
125 159
126 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
127 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
128 162
129 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
130 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
131 165
132 basecoder (const char *cmap); 166 basecoder (const char *cmap);
133}; 167};
134 168
135basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
154 enc_len [len] = n; 188 enc_len [len] = n;
155 dec_len [n] = len; 189 dec_len [n] = len;
156 } 190 }
157} 191}
158 192
193unsigned int
159unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
160{ 195{
161 return enc_len [len]; 196 return enc_len [len];
162} 197}
163 198
199unsigned int
164unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
165{ 201{
166 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
167 --len; 203 --len;
168 204
169 return dec_len [len]; 205 return dec_len [len];
170} 206}
171 207
208unsigned int
172unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
173{ 210{
174 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
175 return 0; 212 return 0;
176 213
177 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
196 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
197 234
198 return elen; 235 return elen;
199} 236}
200 237
238unsigned int
201unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
202{ 240{
203 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
204 return 0; 242 return 0;
205 243
206 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
255 } 293 }
256 abort (); 294 abort ();
257} 295}
258#endif 296#endif
259 297
260//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
261//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
262static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
263//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
264static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
265 301
266///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
267 303
268#define HDRSIZE 6 304#define HDRSIZE 5
269 305
306inline void
270inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
271{ 308{
309 assert (clientid < 256);
310
272 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
273 312
274 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
275 clientid, 316 clientid,
276 (seqno >> 8) | (retry << 6),
277 seqno,
278 }; 317 };
279 318
280 assert (clientid < 256);
281
282 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
283} 320}
284 321
322inline void
285inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
286{ 324{
287 u8 hdr[3]; 325 u8 hdr[3];
288 326
289 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
290 328
291 clientid = hdr[0]; 329 clientid = hdr[2];
292 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
293} 331}
294 332
295///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
296 334
297struct byte_stream 335struct byte_stream
… …
323byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
324{ 362{
325 delete data; 363 delete data;
326} 364}
327 365
366void
328void byte_stream::remove (int count) 367byte_stream::remove (int count)
329{ 368{
330 if (count > fill) 369 if (count > fill)
331 assert (count <= fill); 370 assert (count <= fill);
332 371
333 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
334} 373}
335 374
375bool
336bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
337{ 377{
338 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
339 return false; 379 return false;
340 380
341 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
342 382
343 return true; 383 return true;
344} 384}
345 385
386bool
346bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
347{ 388{
348 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
349 return false; 390 return false;
350 391
351 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
… …
356 return true; 397 return true;
357} 398}
358 399
359vpn_packet *byte_stream::get () 400vpn_packet *byte_stream::get ()
360{ 401{
402 if (fill < 2)
403 return 0;
404
361 unsigned int len; 405 unsigned int len;
362 406
363 for (;;) 407 for (;;)
364 { 408 {
365 len = (data [0] << 8) | data [1]; 409 len = (data [0] << 8) | data [1];
366 410
367 if (len <= MAXSIZE || fill < 2) 411 if (len <= MAXSIZE)
368 break; 412 break;
369 413
370 // TODO: handle this better than skipping, e.g. by reset 414 // TODO: handle this better than skipping, e.g. by reset
371 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]);
372 remove (1); 416 remove (1);
373 } 417 }
374 418
375 if (fill < len + 2) 419 if (fill < len + 2)
376 return 0; 420 return 0;
… …
407 451
408struct dns_cfg 452struct dns_cfg
409{ 453{
410 static int next_uid; 454 static int next_uid;
411 455
456 u8 chksum;
457 u8 rrtype;
458 u16 uid; // to make request unique
459
460 u8 version;
461 u8 flags;
462 u16 max_size;
463
412 u8 id1, id2, id3, id4; 464 u8 id1, id2, id3, id4;
413 u8 version; 465
414 u8 rrtype; 466 u16 client;
415 u8 flags;
416 u8 def_ttl; 467 u8 def_ttl;
417 u8 rcv_cdc; 468 u8 r0;
418 u8 snd_cdc;
419 u16 max_size;
420 u16 client;
421 u16 uid; // to make request unique
422 469
423 u8 reserved[8]; 470 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
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
474
475 u8 r1, r2, r3, r4;
424 476
425 void reset (int clientid); 477 void reset (int clientid);
426 bool valid (); 478 bool valid ();
479 u8 get_chksum ();
427}; 480};
428 481
429int dns_cfg::next_uid; 482int dns_cfg::next_uid;
430 483
484void
431void dns_cfg::reset (int clientid) 485dns_cfg::reset (int clientid)
432{ 486{
487 // this ID must result in some mixed-case characters in cdc26-encoding
433 id1 = 'G'; 488 id1 = 'G';
434 id2 = 'V'; 489 id2 = 'V';
435 id3 = 'P'; 490 id3 = 'P';
436 id4 = 'E'; 491 id4 = 'E';
437 492
438 version = 1; 493 version = 2;
439 494
440 rrtype = RR_TYPE_TXT; 495 rrtype = RR_TYPE_TXT;
441 flags = 0; 496 flags = 0;
442 def_ttl = 1; 497 def_ttl = 0;
443 rcv_cdc = 0;
444 snd_cdc = 62; 498 syn_cdc = 26;
499 hdr_cdc = 36;
500 req_cdc = conf.dns_case_preserving ? 62 : 36;
501 rep_cdc = 0;
445 max_size = ntohs (MAX_PKT_SIZE); 502 max_size = htons (MAX_PKT_SIZE);
446 client = ntohs (clientid); 503 client = htons (clientid);
447 uid = next_uid++; 504 uid = ++next_uid;
448 505
449 memset (reserved, 0, 8); 506 r0 = r1 = r2 = r3 = r4 = 0;
450}
451 507
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
452bool dns_cfg::valid () 529dns_cfg::valid ()
453{ 530{
531 // although the protocol itself allows for some configurability,
532 // only the following encoding/decoding settings are implemented.
454 return id1 == 'G' 533 return id1 == 'G'
455 && id2 == 'V' 534 && id2 == 'V'
456 && id3 == 'P' 535 && id3 == 'P'
457 && id4 == 'E' 536 && id4 == 'E'
458 && version == 1 537 && version == 2
459 && flags == 0
460 && rcv_cdc == 0
461 && snd_cdc == 62 538 && syn_cdc == 26
462 && max_size == ntohs (MAX_PKT_SIZE); 539 && hdr_cdc == 36
540 && (req_cdc == 36 || req_cdc == 62)
541 && rep_cdc == 0
542 && chksum == get_chksum ();
463} 543}
464 544
465struct dns_packet : net_packet 545struct dns_packet : net_packet
466{ 546{
467 u16 id; 547 u16 id;
468 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 548 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
469 u16 qdcount, ancount, nscount, arcount; 549 u16 qdcount, ancount, nscount, arcount;
470 550
471 u8 data[MAXSIZE - 6 * 2]; 551 u8 data [MAXSIZE - 6 * 2];
472 552
473 int decode_label (char *data, int size, int &offs); 553 int decode_label (char *data, int size, int &offs);
474}; 554};
475 555
556int
476int dns_packet::decode_label (char *data, int size, int &offs) 557dns_packet::decode_label (char *data, int size, int &offs)
477{ 558{
478 char *orig = data; 559 char *orig = data;
479 560
480 memset (data, 0, size); 561 memset (data, 0, size);
481 562
… …
507 return data - orig; 588 return data - orig;
508} 589}
509 590
510///////////////////////////////////////////////////////////////////////////// 591/////////////////////////////////////////////////////////////////////////////
511 592
593static
594u16 next_id ()
595{
512static u16 dns_id = 0; // TODO: should be per-vpn 596 static u16 dns_id = 0; // TODO: should be per-vpn
513 597
514static u16 next_id () 598#if 1
515{
516 if (!dns_id) 599 if (!dns_id)
517 dns_id = time (0); 600 dns_id = time (0);
518 601
519 // the simplest lsfr with periodicity 65535 i could find 602 // the simplest lsfr with periodicity 65535 i could find
520 dns_id = (dns_id << 1) 603 dns_id = (dns_id << 1)
… …
522 ^ (dns_id >> 2) 605 ^ (dns_id >> 2)
523 ^ (dns_id >> 4) 606 ^ (dns_id >> 4)
524 ^ (dns_id >> 15)) & 1); 607 ^ (dns_id >> 15)) & 1);
525 608
526 return dns_id; 609 return dns_id;
610#else
611 dns_id++;//D
612
613 return htons (dns_id);
614#endif
527} 615}
528 616
529struct dns_rcv; 617struct dns_rcv;
530struct dns_snd; 618struct dns_snd;
531 619
… …
535 struct vpn *vpn; 623 struct vpn *vpn;
536 624
537 dns_cfg cfg; 625 dns_cfg cfg;
538 626
539 bool established; 627 bool established;
628 const basecoder *cdc;
540 629
541 tstamp last_received; 630 tstamp last_received;
542 tstamp last_sent; 631 tstamp last_sent;
543 double last_latency; 632 double min_latency;
544 double poll_interval, send_interval; 633 double poll_interval, send_interval;
545 634
546 vector<dns_rcv *> rcvpq; 635 vector<dns_rcv *> rcvpq;
547 636
548 byte_stream rcvdq; int rcvseq; 637 byte_stream rcvdq; int rcvseq; int repseq;
549 byte_stream snddq; int sndseq; 638 byte_stream snddq; int sndseq;
550 639
551 void time_cb (time_watcher &w); time_watcher tw; 640 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
552 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
553 645
554 dns_connection (connection *c); 646 dns_connection (connection *c);
555 ~dns_connection (); 647 ~dns_connection ();
556}; 648};
557 649
… …
575: dns (dns) 667: dns (dns)
576{ 668{
577 timeout = 0; 669 timeout = 0;
578 retry = 0; 670 retry = 0;
579 seqno = 0; 671 seqno = 0;
580 sent = NOW; 672 sent = ev_now ();
581 stdhdr = false; 673 stdhdr = false;
582 674
583 pkt = new dns_packet; 675 pkt = new dns_packet;
584 676
585 pkt->id = next_id (); 677 pkt->id = next_id ();
… …
588dns_snd::~dns_snd () 680dns_snd::~dns_snd ()
589{ 681{
590 delete pkt; 682 delete pkt;
591} 683}
592 684
685static void
593static void append_domain (dns_packet &pkt, int &offs, const char *domain) 686append_domain (dns_packet &pkt, int &offs, const char *domain)
594{ 687{
595 // add tunnel domain 688 // add tunnel domain
596 for (;;) 689 for (;;)
597 { 690 {
598 const char *end = strchr (domain, '.'); 691 const char *end = strchr (domain, '.');
… …
611 704
612 domain = end + 1; 705 domain = end + 1;
613 } 706 }
614} 707}
615 708
709void
616void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 710dns_snd::gen_stream_req (int seqno, byte_stream &stream)
617{ 711{
618 stdhdr = true; 712 stdhdr = true;
619 this->seqno = seqno; 713 this->seqno = seqno;
620 714
621 timeout = NOW + INITIAL_TIMEOUT; 715 timeout = ev_now () + INITIAL_TIMEOUT;
622 716
623 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 717 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
624 pkt->qdcount = htons (1); 718 pkt->qdcount = htons (1);
625 719
626 int offs = 6*2; 720 int offs = 6*2;
627 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 721 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
628 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 722 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
629 // 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
630 724
631 char enc[256], *encp = enc; 725 char enc[256], *encp = enc;
632 encode_header (enc, THISNODE->id, seqno); 726 encode_header (enc, THISNODE->id, seqno);
633 727
634 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);
635 729
636 if (datalen > stream.size ()) 730 if (datalen > stream.size ())
637 datalen = stream.size (); 731 datalen = stream.size ();
638 732
639 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 733 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
640 stream.remove (datalen); 734 stream.remove (datalen);
641 735
642 while (enclen) 736 while (enclen)
643 { 737 {
644 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 738 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
650 encp += lbllen; 744 encp += lbllen;
651 745
652 enclen -= lbllen; 746 enclen -= lbllen;
653 } 747 }
654 748
655 append_domain (*pkt, offs, THISNODE->domain); 749 append_domain (*pkt, offs, dns->c->conf->domain);
656 750
657 (*pkt)[offs++] = 0; 751 (*pkt)[offs++] = 0;
658 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 752 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
659 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 753 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
660 754
661 pkt->len = offs; 755 pkt->len = offs;
662} 756}
663 757
758void
664void dns_snd::gen_syn_req () 759dns_snd::gen_syn_req ()
665{ 760{
666 timeout = NOW + INITIAL_SYN_TIMEOUT; 761 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
667
668 printf ("send syn\n");//D
669 762
670 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 763 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
671 pkt->qdcount = htons (1); 764 pkt->qdcount = htons (1);
672 765
673 int offs = 6 * 2; 766 int offs = 6 * 2;
… …
676 769
677 assert (elen <= MAX_LBL_SIZE); 770 assert (elen <= MAX_LBL_SIZE);
678 771
679 (*pkt)[offs] = elen; 772 (*pkt)[offs] = elen;
680 offs += elen + 1; 773 offs += elen + 1;
681 append_domain (*pkt, offs, THISNODE->domain); 774 append_domain (*pkt, offs, dns->c->conf->domain);
682 775
683 (*pkt)[offs++] = 0; 776 (*pkt)[offs++] = 0;
684 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 777 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
685 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 778 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
686 779
… …
712///////////////////////////////////////////////////////////////////////////// 805/////////////////////////////////////////////////////////////////////////////
713 806
714dns_connection::dns_connection (connection *c) 807dns_connection::dns_connection (connection *c)
715: c (c) 808: c (c)
716, rcvdq (MAX_BACKLOG * 2) 809, rcvdq (MAX_BACKLOG * 2)
717, snddq (MAX_BACKLOG * 2) 810, snddq (MAX_BACKLOG)
718, tw (this, &dns_connection::time_cb)
719{ 811{
812 tw.set<dns_connection, &dns_connection::time_cb> (this);
813
720 vpn = c->vpn; 814 vpn = c->vpn;
721 815
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
722 established = false; 840 established = false;
723 841
724 rcvseq = sndseq = 0; 842 rcvseq = repseq = sndseq = 0;
725 843
726 last_sent = last_received = 0; 844 last_sent = 0;
727 poll_interval = MIN_POLL_INTERVAL; 845 poll_interval = 0.5; // starting here
728 send_interval = 0.5; // starting rate 846 send_interval = 0.5; // starting rate
729 last_latency = INITIAL_TIMEOUT; 847 min_latency = INITIAL_TIMEOUT;
730} 848}
731 849
732dns_connection::~dns_connection () 850void
851dns_connection::set_cfg ()
733{ 852{
734 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 853 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
735 i != rcvpq.end ();
736 ++i)
737 delete *i;
738} 854}
739 855
856void
740void dns_connection::receive_rep (dns_rcv *r) 857dns_connection::receive_rep (dns_rcv *r)
741{ 858{
742 if (r->datalen) 859 if (r->datalen)
743 { 860 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
744 last_received = NOW;
745 tw.trigger ();
746
747 poll_interval = send_interval;
748 }
749 else 861 else
750 { 862 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
751 poll_interval *= 1.5;
752 if (poll_interval > MAX_POLL_INTERVAL)
753 poll_interval = MAX_POLL_INTERVAL;
754 }
755 863
756 rcvpq.push_back (r); 864 rcvpq.push_back (r);
757 865
758 redo: 866 redo:
759 867
760 // find next packet 868 // find next packet
761 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 869 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
762 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 870 if (SEQNO_EQ (rcvseq, (*i)->seqno))
763 { 871 {
872 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
764 // enter the packet into our input stream 873 // enter the packet into our input stream
765 r = *i; 874 r = *i;
766 875
767 // remove the oldest packet, look forward, as it's oldest first 876 // remove the oldest packet, look forward, as it's oldest first
768 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 877 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
769 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 878 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
770 { 879 {
880 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
771 delete *j; 881 delete *j;
772 rcvpq.erase (j); 882 rcvpq.erase (j);
773 break; 883 break;
774 } 884 }
775 885
776 rcvseq = (rcvseq + 1) & SEQNO_MASK; 886 rcvseq = (rcvseq + 1) & SEQNO_MASK;
777 887
778 if (!rcvdq.put (r->data, r->datalen)) 888 if (!rcvdq.put (r->data, r->datalen))
779 { 889 {
890 // MUST never overflow, can be caused by data corruption, TODO
780 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 891 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
781 abort (); // MUST never overflow, can be caused by data corruption, TODO 892 reset ();
893 return;
782 } 894 }
783 895
784 while (vpn_packet *pkt = rcvdq.get ()) 896 while (vpn_packet *pkt = rcvdq.get ())
785 { 897 {
786 sockinfo si; 898 sockinfo si;
787 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 899 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
788 900
789 vpn->recv_vpn_packet (pkt, si); 901 vpn->recv_vpn_packet (pkt, si);
790
791 delete pkt; 902 delete pkt;
792 } 903 }
793 904
794 // check for further packets 905 // check for further packets
795 goto redo; 906 goto redo;
… …
806 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 917 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
807 918
808 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 919 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
809 && pkt.qdcount == htons (1)) 920 && pkt.qdcount == htons (1))
810 { 921 {
811 char qname[MAXSIZE]; 922 char qname [MAXSIZE];
812 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 923 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
813 924
814 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 925 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
815 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 926 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
816 927
… …
823 934
824 int dlen = strlen (THISNODE->domain); 935 int dlen = strlen (THISNODE->domain);
825 936
826 if (qclass == RR_CLASS_IN 937 if (qclass == RR_CLASS_IN
827 && qlen > dlen + 1 938 && qlen > dlen + 1
828 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 939 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
829 { 940 {
830 // now generate reply 941 // now generate reply
831 pkt.ancount = htons (1); // one answer RR 942 pkt.ancount = htons (1); // one answer RR
832 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 943 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
833 944
… …
838 { 949 {
839 // correct class, domain: parse 950 // correct class, domain: parse
840 int client, seqno; 951 int client, seqno;
841 decode_header (qname, client, seqno); 952 decode_header (qname, client, seqno);
842 953
843 u8 data[MAXSIZE];
844 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
845
846 if (0 < client && client <= conns.size ()) 954 if (0 < client && client <= conns.size ())
847 { 955 {
848 connection *c = conns [client - 1]; 956 connection *c = conns [client - 1];
849 dns_connection *dns = c->dns; 957 dns_connection *dns = c->dns;
850 dns_rcv *rcv; 958 dns_rcv *rcv;
851 bool in_seq;
852 959
853 if (dns) 960 if (dns)
854 { 961 {
962 u8 data[MAXSIZE];
963 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
964
855 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 (); )
856 if (SEQNO_EQ ((*i)->seqno, seqno)) 966 if (SEQNO_EQ ((*i)->seqno, seqno))
857 { 967 {
858 // already seen that request: simply reply with the cached reply 968 // already seen that request: simply reply with the cached reply
859 dns_rcv *r = *i; 969 dns_rcv *r = *i;
… …
867 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 977 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
868 978
869 goto duplicate_request; 979 goto duplicate_request;
870 } 980 }
871 981
872 in_seq = dns->rcvseq == seqno;
873
874 // new packet, queue 982 // new packet, queue
875 rcv = new dns_rcv (seqno, data, datalen); 983 rcv = new dns_rcv (seqno, data, datalen);
876 dns->receive_rep (rcv); 984 dns->receive_rep (rcv);
877 } 985 }
878 986
987 {
879 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 988 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
880 989
881 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 990 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
882 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 991 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
883 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 992 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
884 pkt [offs++] = 0; pkt [offs++] = 0; 993 pkt [offs++] = 0; pkt [offs++] = 0;
885 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 994 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
886 995
887 int rdlen_offs = offs += 2; 996 int rdlen_offs = offs += 2;
888 997
998 if (dns)
999 {
889 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 1000 int dlen = ntohs (dns->cfg.max_size) - offs;
1001
890 // bind doesn't compress well, so reduce further by one label length 1002 // bind doesn't compress well, so reduce further by one label length
891 dlen -= qlen; 1003 dlen -= qlen;
892 1004
893 if (dns)
894 {
895 // only put data into in-order sequence packets, if 1005 // only put data into in-order sequence packets, if
896 // we receive out-of-order packets we generate empty 1006 // we receive out-of-order packets we generate empty
897 // replies 1007 // replies
898 while (dlen > 1 && !dns->snddq.empty () && in_seq) 1008 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
1009 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
899 { 1010 {
1011 dns->repseq = seqno;
1012
1013 while (dlen > 1 && !dns->snddq.empty ())
1014 {
900 int txtlen = dlen <= 255 ? dlen - 1 : 255; 1015 int txtlen = dlen <= 255 ? dlen - 1 : 255;
901 1016
902 if (txtlen > dns->snddq.size ()) 1017 if (txtlen > dns->snddq.size ())
903 txtlen = dns->snddq.size (); 1018 txtlen = dns->snddq.size ();
904 1019
905 pkt[offs++] = txtlen; 1020 pkt[offs++] = txtlen;
906 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 1021 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
907 offs += txtlen; 1022 offs += txtlen;
908 dns->snddq.remove (txtlen); 1023 dns->snddq.remove (txtlen);
909 1024
910 dlen -= txtlen + 1; 1025 dlen -= txtlen + 1;
1026 }
911 } 1027 }
912 1028
913 // avoid empty TXT rdata 1029 // avoid completely empty TXT rdata
914 if (offs == rdlen_offs) 1030 if (offs == rdlen_offs)
915 pkt[offs++] = 0; 1031 pkt[offs++] = 0;
916 1032
917 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 1033 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
918 } 1034 }
919 else 1035 else
920 { 1036 {
921 // send RST 1037 // send RST
922 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1038 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
923 pkt [offs++] = CMD_IP_RST; 1039 pkt [offs++] = CMD_IP_RST;
924 } 1040 }
925 1041
926 int rdlen = offs - rdlen_offs; 1042 int rdlen = offs - rdlen_offs;
927 1043
928 pkt [rdlen_offs - 2] = rdlen >> 8; 1044 pkt [rdlen_offs - 2] = rdlen >> 8;
929 pkt [rdlen_offs - 1] = rdlen; 1045 pkt [rdlen_offs - 1] = rdlen;
930 1046
931 if (dns) 1047 if (dns)
932 { 1048 {
933 // now update dns_rcv copy 1049 // now update dns_rcv copy
934 rcv->pkt->len = offs; 1050 rcv->pkt->len = offs;
935 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 1051 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
936 } 1052 }
1053 }
937 1054
938 duplicate_request: ; 1055 duplicate_request: ;
939 } 1056 }
940 else 1057 else
941 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 1058 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
953 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
954 pkt [offs++] = 0; pkt [offs++] = 0; 1071 pkt [offs++] = 0; pkt [offs++] = 0;
955 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1072 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
956 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1073 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
957 1074
958 slog (L_INFO, _("DNS: client %d tries to connect"), client);
959
960 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;
961 pkt [offs++] = CMD_IP_REJ; 1076 pkt [offs++] = CMD_IP_REJ;
962 1077
963 if (0 < client && client <= conns.size ()) 1078 if (0 < client && client <= conns.size ())
964 { 1079 {
965 connection *c = conns [client - 1]; 1080 connection *c = conns [client - 1];
966 1081
967 if (cfg.valid ()) 1082 if (cfg.valid ())
968 { 1083 {
969 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));
970 1089
971 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
972 c->dns = new dns_connection (c); 1095 c->dns = new dns_connection (c);
973 c->dns->cfg = cfg; 1096 c->dns->cfg = cfg;
1097 c->dns->set_cfg ();
974 } 1098 }
975 } 1099 }
976 } 1100 }
977 } 1101 }
978 1102
… …
997 { 1121 {
998 dns_connection *dns = (*i)->dns; 1122 dns_connection *dns = (*i)->dns;
999 connection *c = dns->c; 1123 connection *c = dns->c;
1000 int seqno = (*i)->seqno; 1124 int seqno = (*i)->seqno;
1001 u8 data[MAXSIZE], *datap = data; 1125 u8 data[MAXSIZE], *datap = data;
1126 //printf ("rcv pkt %x\n", seqno);//D
1002 1127
1003 if ((*i)->retry) 1128 if ((*i)->retry)
1004 { 1129 {
1005 dns->send_interval *= 1.01; 1130 dns->send_interval *= 1.01;
1006 if (dns->send_interval > MAX_SEND_INTERVAL) 1131 if (dns->send_interval > MAX_SEND_INTERVAL)
1007 dns->send_interval = MAX_SEND_INTERVAL; 1132 dns->send_interval = MAX_SEND_INTERVAL;
1008 } 1133 }
1009 else 1134 else
1010 { 1135 {
1011#if 1 1136#if 0
1012 dns->send_interval *= 0.999; 1137 dns->send_interval *= 0.999;
1013#endif 1138#endif
1014 if (dns->send_interval < MIN_SEND_INTERVAL)
1015 dns->send_interval = MIN_SEND_INTERVAL;
1016
1017 // the latency surely puts an upper bound on 1139 // the latency surely puts an upper bound on
1018 // the minimum send interval 1140 // the minimum send interval
1019 double latency = NOW - (*i)->sent; 1141 double latency = ev_now () - (*i)->sent;
1142
1143 if (latency < dns->min_latency)
1020 dns->last_latency = latency; 1144 dns->min_latency = latency;
1021 1145
1022 if (dns->send_interval > latency) 1146 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1147 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1148
1149 if (dns->send_interval < conf.dns_send_interval)
1023 dns->send_interval = latency; 1150 dns->send_interval = conf.dns_send_interval;
1024 } 1151 }
1025 1152
1026 delete *i; 1153 delete *i;
1027 dns_sndpq.erase (i); 1154 dns_sndpq.erase (i);
1028 1155
… …
1046 ttl |= pkt [offs++] << 16; 1173 ttl |= pkt [offs++] << 16;
1047 ttl |= pkt [offs++] << 8; 1174 ttl |= pkt [offs++] << 8;
1048 ttl |= pkt [offs++]; 1175 ttl |= pkt [offs++];
1049 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1176 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1050 1177
1051 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1178 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1052 { 1179 {
1053 if (rdlen <= MAXSIZE - offs) 1180 if (rdlen <= MAXSIZE - offs)
1054 { 1181 {
1055 // decode bytes, finally 1182 // decode bytes, finally
1056 1183
… …
1082 { 1209 {
1083 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1210 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1084 1211
1085 if (ip [3] == CMD_IP_RST) 1212 if (ip [3] == CMD_IP_RST)
1086 { 1213 {
1087 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1214 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1088 1215
1089 delete dns; c->dns = 0; 1216 dns->reset ();
1090
1091 return; 1217 return;
1092 } 1218 }
1093 else if (ip [3] == CMD_IP_SYN) 1219 else if (ip [3] == CMD_IP_SYN)
1094 { 1220 {
1095 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1221 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1096 dns->established = true; 1222 dns->established = true;
1097 } 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 }
1098 else if (ip [3] == CMD_IP_REJ) 1239 else if (ip [3] == CMD_IP_REJ)
1099 { 1240 {
1100 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."));
1101 abort (); 1242 dns->tw.start (60.);
1102 } 1243 }
1103 else 1244 else
1245 {
1104 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 }
1105 } 1249 }
1106 else 1250 else
1107 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"),
1108 ip [0], ip [1], ip [2], ip [3]); 1252 ip [0], ip [1], ip [2], ip [3]);
1109 1253
… …
1133 break; 1277 break;
1134 } 1278 }
1135} 1279}
1136 1280
1137void 1281void
1138vpn::dnsv4_ev (io_watcher &w, short revents) 1282vpn::dnsv4_ev (ev::io &w, int revents)
1139{ 1283{
1140 if (revents & EVENT_READ) 1284 if (revents & EV_READ)
1141 { 1285 {
1142 dns_packet *pkt = new dns_packet; 1286 dns_packet *pkt = new dns_packet;
1143 struct sockaddr_in sa; 1287 struct sockaddr_in sa;
1144 socklen_t sa_len = sizeof (sa); 1288 socklen_t sa_len = sizeof (sa);
1145 1289
1146 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1290 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1147 1291
1148 if (pkt->len > 0) 1292 if (pkt->len > 0)
1149 { 1293 {
1150 if (THISNODE->dns_port) 1294 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1295 dnsv4_client (*pkt);
1296 else
1151 { 1297 {
1152 dnsv4_server (*pkt); 1298 dnsv4_server (*pkt);
1153 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1299 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1154 } 1300 }
1155 else
1156 dnsv4_client (*pkt);
1157 1301
1158 delete pkt; 1302 delete pkt;
1159 } 1303 }
1160 } 1304 }
1161} 1305}
1162 1306
1163bool 1307bool
1164vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1308vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1165{ 1309{
1166 int client = ntohs (si.port); 1310 int client = ntohl (si.host);
1167 1311
1168 assert (0 < client && client <= conns.size ()); 1312 assert (0 < client && client <= conns.size ());
1169 1313
1170 connection *c = conns [client - 1]; 1314 connection *c = conns [client - 1];
1171 1315
1172 if (!c->dns) 1316 if (!c->dns)
1173 c->dns = new dns_connection (c); 1317 c->dns = new dns_connection (c);
1174 1318
1175 if (!c->dns->snddq.put (pkt)) 1319 if (c->dns->snddq.put (pkt))
1176 return false; 1320 {
1321 min_it (c->dns->poll_interval, 0.25);
1322 c->dns->tw ();
1323 }
1177 1324
1178 c->dns->tw.trigger (); 1325 // always return true even if the buffer overflows
1179
1180 return true; 1326 return true;
1181} 1327}
1182 1328
1183void 1329void
1184connection::dnsv4_reset_connection () 1330dns_connection::time_cb (ev::timer &w, int revents)
1185{
1186 //delete dns; dns = 0; //TODO
1187}
1188
1189#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1190
1191void
1192dns_connection::time_cb (time_watcher &w)
1193{ 1331{
1194 // servers have to be polled 1332 // servers have to be polled
1195 if (THISNODE->dns_port) 1333 if (THISNODE->dns_port)
1196 return; 1334 return;
1197 1335
1198 // check for timeouts and (re)transmit 1336 // check for timeouts and (re)transmit
1199 tstamp next = NOW + poll_interval; 1337 tstamp next = 86400 * 365;
1200 dns_snd *send = 0; 1338 dns_snd *send = 0;
1201 1339
1202 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1340 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1203 i != vpn->dns_sndpq.end (); 1341 i != vpn->dns_sndpq.end ();
1204 ++i) 1342 ++i)
1205 { 1343 {
1206 dns_snd *r = *i; 1344 dns_snd *r = *i;
1207 1345
1208 if (r->timeout <= NOW) 1346 if (r->timeout <= ev_now ())
1209 { 1347 {
1210 if (!send) 1348 if (!send)
1211 { 1349 {
1212 send = r; 1350 send = r;
1213 1351
1214 r->retry++; 1352 r->retry++;
1215 r->timeout = NOW + (r->retry * last_latency * 8.); 1353 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1354 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1216 1355
1217 // the following code changes the query section a bit, forcing 1356 // the following code changes the query section a bit, forcing
1218 // the forwarder to generate a new request 1357 // the forwarder to generate a new request
1219 if (r->stdhdr) 1358 if (r->stdhdr)
1220 {
1221 //printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1222 //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);
1223 }
1224 } 1360 }
1225 } 1361 }
1226 else 1362 else
1227 NEXT (r->timeout); 1363 min_it (next, r->timeout - ev_now ());
1228 }
1229
1230 if (last_sent + send_interval <= NOW)
1231 { 1364 }
1365
1232 if (!send) 1366 if (!send)
1367 {
1368 // generate a new packet, if wise
1369
1370 if (!established)
1233 { 1371 {
1234 // generate a new packet, if wise 1372 if (vpn->dns_sndpq.empty ())
1235
1236 if (!established)
1237 { 1373 {
1238 if (vpn->dns_sndpq.empty ())
1239 {
1240 send = new dns_snd (this); 1374 send = new dns_snd (this);
1241 1375
1242 printf ("new conn %p %d\n", this, c->conf->id);//D
1243 cfg.reset (THISNODE->id); 1376 cfg.reset (THISNODE->id);
1377 set_cfg ();
1244 send->gen_syn_req (); 1378 send->gen_syn_req ();
1245 }
1246 } 1379 }
1247 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1380 }
1381 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1248 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1382 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1383 {
1384 if (last_sent + send_interval <= ev_now ())
1249 { 1385 {
1250 //printf ("sending data request etc.\n"); //D 1386 //printf ("sending data request etc.\n"); //D
1251 if (!snddq.empty ()) 1387 if (!snddq.empty ())
1252 {
1253 poll_interval = send_interval;
1254 NEXT (NOW + send_interval); 1388 min_it (next, send_interval);
1255 }
1256 1389
1257 send = new dns_snd (this); 1390 send = new dns_snd (this);
1258 send->gen_stream_req (sndseq, snddq); 1391 send->gen_stream_req (sndseq, snddq);
1259 send->timeout = NOW + last_latency * 8.; 1392 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1393 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1260 1394
1261 sndseq = (sndseq + 1) & SEQNO_MASK; 1395 sndseq = (sndseq + 1) & SEQNO_MASK;
1262 } 1396 }
1263 1397 else
1264 if (send) 1398 min_it (next, last_sent + send_interval - ev_now ());
1265 vpn->dns_sndpq.push_back (send);
1266 } 1399 }
1267 1400
1268 if (send) 1401 if (send)
1269 { 1402 vpn->dns_sndpq.push_back (send);
1270 last_sent = NOW; 1403 }
1404
1405 if (send)
1406 {
1407 last_sent = ev_now ();
1271 sendto (vpn->dnsv4_fd, 1408 sendto (vpn->dnsv4_fd,
1272 send->pkt->at (0), send->pkt->len, 0, 1409 send->pkt->at (0), send->pkt->len, 0,
1273 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1410 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1274 }
1275 } 1411 }
1276 else
1277 NEXT (last_sent + send_interval);
1278 1412
1413 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1414
1279 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1415 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1280 poll_interval, send_interval, next - NOW, 1416 poll_interval, send_interval, next - ev_now (),
1281 vpn->dns_sndpq.size (), snddq.size ()); 1417 vpn->dns_sndpq.size (), snddq.size (),
1282 1418 rcvpq.size ());
1283 // TODO: no idea when this happens, but when next < NOW, we have a problem
1284 if (next < NOW + 0.0001)
1285 next = NOW + 0.1;
1286 1419
1287 w.start (next); 1420 w.start (next);
1288} 1421}
1289 1422
1290#endif 1423#endif

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