ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/gvpe/src/vpn_dns.C
(Generate patch)

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.17 by pcg, Sat Mar 5 03:47:05 2005 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. 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 unsigned int len;
403
404 for (;;)
405 {
361 unsigned int len = (data [0] << 8) | data [1]; 406 len = (data [0] << 8) | data [1];
362 407
363 if (len > MAXSIZE && fill >= 2) 408 if (len <= MAXSIZE || fill < 2)
364 assert (len <= MAXSIZE || fill < 2); // TODO handle this gracefully, connection reset 409 break;
365 410
411 // TODO: handle this better than skipping, e.g. by reset
412 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
413 remove (1);
414 }
415
366 if (fill < len + 2) 416 if (fill < len + 2)
367 return 0; 417 return 0;
368 418
369 vpn_packet *pkt = new vpn_packet; 419 vpn_packet *pkt = new vpn_packet;
370 420
… …
398 448
399struct dns_cfg 449struct dns_cfg
400{ 450{
401 static int next_uid; 451 static int next_uid;
402 452
453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
456
457 u8 version;
458 u8 flags;
459 u16 max_size;
460
403 u8 id1, id2, id3, id4; 461 u8 id1, id2, id3, id4;
404 u8 version; 462
405 u8 rrtype; 463 u16 client;
406 u8 flags;
407 u8 def_ttl; 464 u8 def_ttl;
408 u8 rcv_cdc; 465 u8 r0;
409 u8 snd_cdc;
410 u16 max_size;
411 u16 client;
412 u16 uid; // to make request unique
413 466
414 u8 reserved[8]; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
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
471
472 u8 r1, r2, r3, r4;
415 473
416 void reset (int clientid); 474 void reset (int clientid);
417 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
418}; 477};
419 478
420int dns_cfg::next_uid; 479int dns_cfg::next_uid;
421 480
481void
422void dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
423{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
424 id1 = 'G'; 485 id1 = 'G';
425 id2 = 'V'; 486 id2 = 'V';
426 id3 = 'P'; 487 id3 = 'P';
427 id4 = 'E'; 488 id4 = 'E';
428 489
429 version = 1; 490 version = 2;
430 491
431 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
432 flags = 0; 493 flags = 0;
433 def_ttl = 1; 494 def_ttl = 0;
434 rcv_cdc = 0;
435 snd_cdc = 62; 495 syn_cdc = 26;
496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
498 rep_cdc = 0;
436 max_size = ntohs (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
437 client = ntohs (clientid); 500 client = htons (clientid);
438 uid = next_uid++; 501 uid = ++next_uid;
439 502
440 memset (reserved, 0, 8); 503 r0 = r1 = r2 = r3 = r4 = 0;
441}
442 504
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
443bool dns_cfg::valid () 526dns_cfg::valid ()
444{ 527{
528 // although the protocol itself allows for some configurability,
529 // only the following encoding/decoding settings are implemented.
445 return id1 == 'G' 530 return id1 == 'G'
446 && id2 == 'V' 531 && id2 == 'V'
447 && id3 == 'P' 532 && id3 == 'P'
448 && id4 == 'E' 533 && id4 == 'E'
449 && version == 1 534 && version == 2
450 && flags == 0
451 && rcv_cdc == 0
452 && snd_cdc == 62 535 && syn_cdc == 26
453 && max_size == ntohs (MAX_PKT_SIZE); 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
538 && rep_cdc == 0
539 && chksum == get_chksum ();
454} 540}
455 541
456struct dns_packet : net_packet 542struct dns_packet : net_packet
457{ 543{
458 u16 id; 544 u16 id;
459 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 545 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
460 u16 qdcount, ancount, nscount, arcount; 546 u16 qdcount, ancount, nscount, arcount;
461 547
462 u8 data[MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
463 549
464 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
465}; 551};
466 552
553int
467int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
468{ 555{
469 char *orig = data; 556 char *orig = data;
470 557
471 memset (data, 0, size); 558 memset (data, 0, size);
472 559
… …
498 return data - orig; 585 return data - orig;
499} 586}
500 587
501///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
502 589
590static
591u16 next_id ()
592{
593 static u16 dns_id = 0; // TODO: should be per-vpn
594
595#if 1
596 if (!dns_id)
597 dns_id = time (0);
598
599 // the simplest lsfr with periodicity 65535 i could find
600 dns_id = (dns_id << 1)
601 | (((dns_id >> 1)
602 ^ (dns_id >> 2)
603 ^ (dns_id >> 4)
604 ^ (dns_id >> 15)) & 1);
605
606 return dns_id;
607#else
608 dns_id++;//D
609
610 return htons (dns_id);
611#endif
612}
613
614struct dns_rcv;
615struct dns_snd;
616
617struct dns_connection
618{
619 connection *c;
620 struct vpn *vpn;
621
622 dns_cfg cfg;
623
624 bool established;
625 const basecoder *cdc;
626
627 tstamp last_received;
628 tstamp last_sent;
629 double min_latency;
630 double poll_interval, send_interval;
631
632 vector<dns_rcv *> rcvpq;
633
634 byte_stream rcvdq; int rcvseq; int repseq;
635 byte_stream snddq; int sndseq;
636
637 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
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
642
643 dns_connection (connection *c);
644 ~dns_connection ();
645};
646
503struct dns_snd 647struct dns_snd
504{ 648{
505 dns_packet *pkt; 649 dns_packet *pkt;
506 tstamp timeout, sent; 650 tstamp timeout, sent;
507 int retry; 651 int retry;
508 struct dns_connection *dns; 652 struct dns_connection *dns;
509 int seqno; 653 int seqno;
510 bool stdhdr; 654 bool stdhdr;
511 655
512 void gen_stream_req (int seqno, byte_stream &stream); 656 void gen_stream_req (int seqno, byte_stream &stream);
513 void gen_syn_req (const dns_cfg &cfg); 657 void gen_syn_req ();
514 658
515 dns_snd (dns_connection *dns); 659 dns_snd (dns_connection *dns);
516 ~dns_snd (); 660 ~dns_snd ();
517}; 661};
518 662
519static u16 dns_id = 12098; // TODO: should be per-vpn
520
521static u16 next_id ()
522{
523 // the simplest lsfr with periodicity 65535 i could find
524 dns_id = (dns_id << 1)
525 | (((dns_id >> 1)
526 ^ (dns_id >> 2)
527 ^ (dns_id >> 4)
528 ^ (dns_id >> 15)) & 1);
529
530 return dns_id;
531}
532
533dns_snd::dns_snd (dns_connection *dns) 663dns_snd::dns_snd (dns_connection *dns)
534: dns (dns) 664: dns (dns)
535{ 665{
536 timeout = 0; 666 timeout = 0;
537 retry = 0; 667 retry = 0;
538 seqno = 0; 668 seqno = 0;
539 sent = NOW; 669 sent = ev_now ();
540 stdhdr = false; 670 stdhdr = false;
541 671
542 pkt = new dns_packet; 672 pkt = new dns_packet;
543 673
544 pkt->id = next_id (); 674 pkt->id = next_id ();
… …
547dns_snd::~dns_snd () 677dns_snd::~dns_snd ()
548{ 678{
549 delete pkt; 679 delete pkt;
550} 680}
551 681
682static void
552static void append_domain (dns_packet &pkt, int &offs, const char *domain) 683append_domain (dns_packet &pkt, int &offs, const char *domain)
553{ 684{
554 // add tunnel domain 685 // add tunnel domain
555 for (;;) 686 for (;;)
556 { 687 {
557 const char *end = strchr (domain, '.'); 688 const char *end = strchr (domain, '.');
… …
570 701
571 domain = end + 1; 702 domain = end + 1;
572 } 703 }
573} 704}
574 705
706void
575void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 707dns_snd::gen_stream_req (int seqno, byte_stream &stream)
576{ 708{
577 stdhdr = true; 709 stdhdr = true;
578 this->seqno = seqno; 710 this->seqno = seqno;
579 711
580 timeout = NOW + INITIAL_TIMEOUT; 712 timeout = ev_now () + INITIAL_TIMEOUT;
581 713
582 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 714 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
583 pkt->qdcount = htons (1); 715 pkt->qdcount = htons (1);
584 716
585 int offs = 6*2; 717 int offs = 6*2;
586 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 718 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
587 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 719 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
588 // 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
589 721
590 char enc[256], *encp = enc; 722 char enc[256], *encp = enc;
591 encode_header (enc, THISNODE->id, seqno); 723 encode_header (enc, THISNODE->id, seqno);
592 724
593 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);
594 726
595 if (datalen > stream.size ()) 727 if (datalen > stream.size ())
596 datalen = stream.size (); 728 datalen = stream.size ();
597 729
598 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 730 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
599 stream.remove (datalen); 731 stream.remove (datalen);
600 732
601 while (enclen) 733 while (enclen)
602 { 734 {
603 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 735 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
609 encp += lbllen; 741 encp += lbllen;
610 742
611 enclen -= lbllen; 743 enclen -= lbllen;
612 } 744 }
613 745
614 append_domain (*pkt, offs, THISNODE->domain); 746 append_domain (*pkt, offs, dns->c->conf->domain);
615 747
616 (*pkt)[offs++] = 0; 748 (*pkt)[offs++] = 0;
617 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 749 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
618 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 750 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
619 751
620 pkt->len = offs; 752 pkt->len = offs;
621} 753}
622 754
623void dns_snd::gen_syn_req (const dns_cfg &cfg) 755void
756dns_snd::gen_syn_req ()
624{ 757{
625 timeout = NOW + INITIAL_SYN_TIMEOUT; 758 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
626 759
627 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 760 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
628 pkt->qdcount = htons (1); 761 pkt->qdcount = htons (1);
629 762
630 int offs = 6*2; 763 int offs = 6 * 2;
631 764
632 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); 765 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg));
633 766
634 assert (elen <= MAX_LBL_SIZE); 767 assert (elen <= MAX_LBL_SIZE);
635 768
636 (*pkt)[offs] = elen; 769 (*pkt)[offs] = elen;
637 offs += elen + 1; 770 offs += elen + 1;
638 append_domain (*pkt, offs, THISNODE->domain); 771 append_domain (*pkt, offs, dns->c->conf->domain);
639 772
640 (*pkt)[offs++] = 0; 773 (*pkt)[offs++] = 0;
641 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 774 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
642 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 775 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
643 776
… …
666 delete pkt; 799 delete pkt;
667} 800}
668 801
669///////////////////////////////////////////////////////////////////////////// 802/////////////////////////////////////////////////////////////////////////////
670 803
671struct dns_connection
672{
673 connection *c;
674 struct vpn *vpn;
675
676 dns_cfg cfg;
677
678 bool established;
679
680 tstamp last_received;
681 tstamp last_sent;
682 double last_latency;
683 double poll_interval, send_interval;
684
685 vector<dns_rcv *> rcvpq;
686
687 byte_stream rcvdq; int rcvseq;
688 byte_stream snddq; int sndseq;
689
690 void time_cb (time_watcher &w); time_watcher tw;
691 void receive_rep (dns_rcv *r);
692
693 dns_connection (connection *c);
694 ~dns_connection ();
695};
696
697dns_connection::dns_connection (connection *c) 804dns_connection::dns_connection (connection *c)
698: c (c) 805: c (c)
699, rcvdq (MAX_BACKLOG * 2) 806, rcvdq (MAX_BACKLOG * 2)
700, snddq (MAX_BACKLOG * 2) 807, snddq (MAX_BACKLOG)
701, tw (this, &dns_connection::time_cb)
702{ 808{
809 tw.set<dns_connection, &dns_connection::time_cb> (this);
810
703 vpn = c->vpn; 811 vpn = c->vpn;
704 812
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
705 established = false; 837 established = false;
706 838
707 rcvseq = sndseq = 0; 839 rcvseq = repseq = sndseq = 0;
708 840
709 last_sent = last_received = 0; 841 last_sent = 0;
710 poll_interval = MIN_POLL_INTERVAL; 842 poll_interval = 0.5; // starting here
711 send_interval = 0.5; // starting rate 843 send_interval = 0.5; // starting rate
712 last_latency = INITIAL_TIMEOUT; 844 min_latency = INITIAL_TIMEOUT;
713} 845}
714 846
715dns_connection::~dns_connection () 847void
848dns_connection::set_cfg ()
716{ 849{
717 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 850 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
718 i != rcvpq.end ();
719 ++i)
720 delete *i;
721} 851}
722 852
853void
723void dns_connection::receive_rep (dns_rcv *r) 854dns_connection::receive_rep (dns_rcv *r)
724{ 855{
725 if (r->datalen) 856 if (r->datalen)
726 { 857 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
727 last_received = NOW;
728 tw.trigger ();
729
730 poll_interval = send_interval;
731 }
732 else 858 else
733 { 859 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
734 poll_interval *= 1.5;
735 if (poll_interval > MAX_POLL_INTERVAL)
736 poll_interval = MAX_POLL_INTERVAL;
737 }
738 860
739 rcvpq.push_back (r); 861 rcvpq.push_back (r);
740 862
741 redo: 863 redo:
742 864
743 // find next packet 865 // find next packet
744 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 866 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
745 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 867 if (SEQNO_EQ (rcvseq, (*i)->seqno))
746 { 868 {
869 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
747 // enter the packet into our input stream 870 // enter the packet into our input stream
748 r = *i; 871 r = *i;
749 872
750 // remove the oldest packet, look forward, as it's oldest first 873 // remove the oldest packet, look forward, as it's oldest first
751 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 874 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
752 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 875 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
753 { 876 {
877 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
754 delete *j; 878 delete *j;
755 rcvpq.erase (j); 879 rcvpq.erase (j);
756 break; 880 break;
757 } 881 }
758 882
759 rcvseq = (rcvseq + 1) & SEQNO_MASK; 883 rcvseq = (rcvseq + 1) & SEQNO_MASK;
760 884
761 if (!rcvdq.put (r->data, r->datalen)) 885 if (!rcvdq.put (r->data, r->datalen))
762 { 886 {
887 // MUST never overflow, can be caused by data corruption, TODO
763 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 888 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
764 abort (); // MUST never overflow, can be caused by data corruption, TODO 889 reset ();
890 return;
765 } 891 }
766 892
767 while (vpn_packet *pkt = rcvdq.get ()) 893 while (vpn_packet *pkt = rcvdq.get ())
768 { 894 {
769 sockinfo si; 895 sockinfo si;
770 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 896 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
771 897
772 vpn->recv_vpn_packet (pkt, si); 898 vpn->recv_vpn_packet (pkt, si);
773
774 delete pkt; 899 delete pkt;
775 } 900 }
776 901
777 // check for further packets 902 // check for further packets
778 goto redo; 903 goto redo;
… …
789 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 914 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
790 915
791 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 916 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
792 && pkt.qdcount == htons (1)) 917 && pkt.qdcount == htons (1))
793 { 918 {
794 char qname[MAXSIZE]; 919 char qname [MAXSIZE];
795 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 920 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
796 921
797 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 922 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
798 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 923 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
799 924
… …
806 931
807 int dlen = strlen (THISNODE->domain); 932 int dlen = strlen (THISNODE->domain);
808 933
809 if (qclass == RR_CLASS_IN 934 if (qclass == RR_CLASS_IN
810 && qlen > dlen + 1 935 && qlen > dlen + 1
811 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 936 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
812 { 937 {
813 // now generate reply 938 // now generate reply
814 pkt.ancount = htons (1); // one answer RR 939 pkt.ancount = htons (1); // one answer RR
815 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 940 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
816 941
… …
821 { 946 {
822 // correct class, domain: parse 947 // correct class, domain: parse
823 int client, seqno; 948 int client, seqno;
824 decode_header (qname, client, seqno); 949 decode_header (qname, client, seqno);
825 950
826 u8 data[MAXSIZE];
827 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
828
829 if (0 < client && client <= conns.size ()) 951 if (0 < client && client <= conns.size ())
830 { 952 {
831 connection *c = conns [client - 1]; 953 connection *c = conns [client - 1];
832 dns_connection *dns = c->dns; 954 dns_connection *dns = c->dns;
833 dns_rcv *rcv; 955 dns_rcv *rcv;
834 bool in_seq;
835 956
836 if (dns) 957 if (dns)
837 { 958 {
959 u8 data[MAXSIZE];
960 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
961
838 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 (); )
839 if (SEQNO_EQ ((*i)->seqno, seqno)) 963 if (SEQNO_EQ ((*i)->seqno, seqno))
840 { 964 {
841 // already seen that request: simply reply with the cached reply 965 // already seen that request: simply reply with the cached reply
842 dns_rcv *r = *i; 966 dns_rcv *r = *i;
… …
850 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 974 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
851 975
852 goto duplicate_request; 976 goto duplicate_request;
853 } 977 }
854 978
855 in_seq = dns->rcvseq == seqno;
856
857 // new packet, queue 979 // new packet, queue
858 rcv = new dns_rcv (seqno, data, datalen); 980 rcv = new dns_rcv (seqno, data, datalen);
859 dns->receive_rep (rcv); 981 dns->receive_rep (rcv);
860 } 982 }
861 983
984 {
862 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 985 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
863 986
864 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 987 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
865 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 988 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
866 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 989 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
867 pkt [offs++] = 0; pkt [offs++] = 0; 990 pkt [offs++] = 0; pkt [offs++] = 0;
868 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 991 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
869 992
870 int rdlen_offs = offs += 2; 993 int rdlen_offs = offs += 2;
871 994
995 if (dns)
996 {
872 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 997 int dlen = ntohs (dns->cfg.max_size) - offs;
998
873 // bind doesn't compress well, so reduce further by one label length 999 // bind doesn't compress well, so reduce further by one label length
874 dlen -= qlen; 1000 dlen -= qlen;
875 1001
876 if (dns)
877 {
878 // only put data into in-order sequence packets, if 1002 // only put data into in-order sequence packets, if
879 // we receive out-of-order packets we generate empty 1003 // we receive out-of-order packets we generate empty
880 // replies 1004 // replies
881 while (dlen > 1 && !dns->snddq.empty () && in_seq) 1005 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
1006 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
882 { 1007 {
1008 dns->repseq = seqno;
1009
1010 while (dlen > 1 && !dns->snddq.empty ())
1011 {
883 int txtlen = dlen <= 255 ? dlen - 1 : 255; 1012 int txtlen = dlen <= 255 ? dlen - 1 : 255;
884 1013
885 if (txtlen > dns->snddq.size ()) 1014 if (txtlen > dns->snddq.size ())
886 txtlen = dns->snddq.size (); 1015 txtlen = dns->snddq.size ();
887 1016
888 pkt[offs++] = txtlen; 1017 pkt[offs++] = txtlen;
889 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 1018 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
890 offs += txtlen; 1019 offs += txtlen;
891 dns->snddq.remove (txtlen); 1020 dns->snddq.remove (txtlen);
892 1021
893 dlen -= txtlen + 1; 1022 dlen -= txtlen + 1;
1023 }
894 } 1024 }
895 1025
896 // avoid empty TXT rdata 1026 // avoid completely empty TXT rdata
897 if (offs == rdlen_offs) 1027 if (offs == rdlen_offs)
898 pkt[offs++] = 0; 1028 pkt[offs++] = 0;
899 1029
900 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 1030 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
901 } 1031 }
902 else 1032 else
903 { 1033 {
904 // send RST 1034 // send RST
905 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1035 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
906 pkt [offs++] = CMD_IP_RST; 1036 pkt [offs++] = CMD_IP_RST;
907 } 1037 }
908 1038
909 int rdlen = offs - rdlen_offs; 1039 int rdlen = offs - rdlen_offs;
910 1040
911 pkt [rdlen_offs - 2] = rdlen >> 8; 1041 pkt [rdlen_offs - 2] = rdlen >> 8;
912 pkt [rdlen_offs - 1] = rdlen; 1042 pkt [rdlen_offs - 1] = rdlen;
913 1043
914 if (dns) 1044 if (dns)
915 { 1045 {
916 // now update dns_rcv copy 1046 // now update dns_rcv copy
917 rcv->pkt->len = offs; 1047 rcv->pkt->len = offs;
918 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 1048 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
919 } 1049 }
1050 }
920 1051
921 duplicate_request: ; 1052 duplicate_request: ;
922 } 1053 }
923 else 1054 else
924 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 1055 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
936 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
937 pkt [offs++] = 0; pkt [offs++] = 0; 1068 pkt [offs++] = 0; pkt [offs++] = 0;
938 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1069 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
939 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1070 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
940 1071
941 slog (L_INFO, _("DNS: client %d tries to connect"), client);
942
943 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;
944 pkt [offs++] = CMD_IP_REJ; 1073 pkt [offs++] = CMD_IP_REJ;
945 1074
946 if (0 < client && client <= conns.size ()) 1075 if (0 < client && client <= conns.size ())
947 { 1076 {
948 connection *c = conns [client - 1]; 1077 connection *c = conns [client - 1];
949 1078
950 if (cfg.valid ()) 1079 if (cfg.valid ())
951 { 1080 {
952 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));
953 1086
954 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
955 c->dns = new dns_connection (c); 1092 c->dns = new dns_connection (c);
956 c->dns->cfg = cfg; 1093 c->dns->cfg = cfg;
1094 c->dns->set_cfg ();
957 } 1095 }
958 } 1096 }
959 } 1097 }
960 } 1098 }
961 1099
… …
980 { 1118 {
981 dns_connection *dns = (*i)->dns; 1119 dns_connection *dns = (*i)->dns;
982 connection *c = dns->c; 1120 connection *c = dns->c;
983 int seqno = (*i)->seqno; 1121 int seqno = (*i)->seqno;
984 u8 data[MAXSIZE], *datap = data; 1122 u8 data[MAXSIZE], *datap = data;
1123 //printf ("rcv pkt %x\n", seqno);//D
985 1124
986 if ((*i)->retry) 1125 if ((*i)->retry)
987 { 1126 {
988 dns->send_interval *= 1.01; 1127 dns->send_interval *= 1.01;
989 if (dns->send_interval > MAX_SEND_INTERVAL) 1128 if (dns->send_interval > MAX_SEND_INTERVAL)
990 dns->send_interval = MAX_SEND_INTERVAL; 1129 dns->send_interval = MAX_SEND_INTERVAL;
991 } 1130 }
992 else 1131 else
993 { 1132 {
994#if 1 1133#if 0
995 dns->send_interval *= 0.999; 1134 dns->send_interval *= 0.999;
996#endif 1135#endif
997 if (dns->send_interval < MIN_SEND_INTERVAL)
998 dns->send_interval = MIN_SEND_INTERVAL;
999
1000 // the latency surely puts an upper bound on 1136 // the latency surely puts an upper bound on
1001 // the minimum send interval 1137 // the minimum send interval
1002 double latency = NOW - (*i)->sent; 1138 double latency = ev_now () - (*i)->sent;
1139
1140 if (latency < dns->min_latency)
1003 dns->last_latency = latency; 1141 dns->min_latency = latency;
1004 1142
1005 if (dns->send_interval > latency) 1143 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1144 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1145
1146 if (dns->send_interval < conf.dns_send_interval)
1006 dns->send_interval = latency; 1147 dns->send_interval = conf.dns_send_interval;
1007 } 1148 }
1008 1149
1009 delete *i; 1150 delete *i;
1010 dns_sndpq.erase (i); 1151 dns_sndpq.erase (i);
1011 1152
… …
1029 ttl |= pkt [offs++] << 16; 1170 ttl |= pkt [offs++] << 16;
1030 ttl |= pkt [offs++] << 8; 1171 ttl |= pkt [offs++] << 8;
1031 ttl |= pkt [offs++]; 1172 ttl |= pkt [offs++];
1032 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1173 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1033 1174
1034 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1175 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1035 { 1176 {
1036 if (rdlen <= MAXSIZE - offs) 1177 if (rdlen <= MAXSIZE - offs)
1037 { 1178 {
1038 // decode bytes, finally 1179 // decode bytes, finally
1039 1180
… …
1065 { 1206 {
1066 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1207 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1067 1208
1068 if (ip [3] == CMD_IP_RST) 1209 if (ip [3] == CMD_IP_RST)
1069 { 1210 {
1070 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1211 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1071 1212
1072 delete dns; c->dns = 0; 1213 dns->reset ();
1073
1074 return; 1214 return;
1075 } 1215 }
1076 else if (ip [3] == CMD_IP_SYN) 1216 else if (ip [3] == CMD_IP_SYN)
1077 { 1217 {
1078 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1218 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1079 dns->established = true; 1219 dns->established = true;
1080 } 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 }
1081 else if (ip [3] == CMD_IP_REJ) 1236 else if (ip [3] == CMD_IP_REJ)
1082 { 1237 {
1083 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."));
1084 abort (); 1239 dns->tw.start (60.);
1085 } 1240 }
1086 else 1241 else
1242 {
1087 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 }
1088 } 1246 }
1089 else 1247 else
1090 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"),
1091 ip [0], ip [1], ip [2], ip [3]); 1249 ip [0], ip [1], ip [2], ip [3]);
1092 1250
… …
1116 break; 1274 break;
1117 } 1275 }
1118} 1276}
1119 1277
1120void 1278void
1121vpn::dnsv4_ev (io_watcher &w, short revents) 1279vpn::dnsv4_ev (ev::io &w, int revents)
1122{ 1280{
1123 if (revents & EVENT_READ) 1281 if (revents & EV_READ)
1124 { 1282 {
1125 dns_packet *pkt = new dns_packet; 1283 dns_packet *pkt = new dns_packet;
1126 struct sockaddr_in sa; 1284 struct sockaddr_in sa;
1127 socklen_t sa_len = sizeof (sa); 1285 socklen_t sa_len = sizeof (sa);
1128 1286
1129 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1287 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1130 1288
1131 if (pkt->len > 0) 1289 if (pkt->len > 0)
1132 { 1290 {
1133 if (THISNODE->dns_port) 1291 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1292 dnsv4_client (*pkt);
1293 else
1134 { 1294 {
1135 dnsv4_server (*pkt); 1295 dnsv4_server (*pkt);
1136 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1296 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1137 } 1297 }
1138 else
1139 dnsv4_client (*pkt);
1140 1298
1141 delete pkt; 1299 delete pkt;
1142 } 1300 }
1143 } 1301 }
1144} 1302}
1145 1303
1146bool 1304bool
1147connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1305vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1148{ 1306{
1307 int client = ntohl (si.host);
1308
1309 assert (0 < client && client <= conns.size ());
1310
1311 connection *c = conns [client - 1];
1312
1149 if (!dns) 1313 if (!c->dns)
1150 dns = new dns_connection (this); 1314 c->dns = new dns_connection (c);
1151 1315
1152 if (!dns->snddq.put (pkt)) 1316 if (c->dns->snddq.put (pkt))
1153 return false; 1317 {
1318 min_it (c->dns->poll_interval, 0.25);
1319 c->dns->tw ();
1320 }
1154 1321
1155 dns->tw.trigger (); 1322 // always return true even if the buffer overflows
1156
1157 return true; 1323 return true;
1158} 1324}
1159 1325
1160void 1326void
1161connection::dnsv4_reset_connection () 1327dns_connection::time_cb (ev::timer &w, int revents)
1162{
1163 //delete dns; dns = 0; //TODO
1164}
1165
1166#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1167
1168void
1169dns_connection::time_cb (time_watcher &w)
1170{ 1328{
1171 // servers have to be polled 1329 // servers have to be polled
1172 if (THISNODE->dns_port) 1330 if (THISNODE->dns_port)
1173 return; 1331 return;
1174 1332
1175 // check for timeouts and (re)transmit 1333 // check for timeouts and (re)transmit
1176 tstamp next = NOW + poll_interval; 1334 tstamp next = 86400 * 365;
1177 dns_snd *send = 0; 1335 dns_snd *send = 0;
1178 1336
1179 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1337 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1180 i != vpn->dns_sndpq.end (); 1338 i != vpn->dns_sndpq.end ();
1181 ++i) 1339 ++i)
1182 { 1340 {
1183 dns_snd *r = *i; 1341 dns_snd *r = *i;
1184 1342
1185 if (r->timeout <= NOW) 1343 if (r->timeout <= ev_now ())
1186 { 1344 {
1187 if (!send) 1345 if (!send)
1188 { 1346 {
1189 send = r; 1347 send = r;
1190 1348
1191 r->retry++; 1349 r->retry++;
1192 r->timeout = NOW + (r->retry * last_latency * 8.); 1350 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1351 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1193 1352
1194 // the following code changes the query section a bit, forcing 1353 // the following code changes the query section a bit, forcing
1195 // the forwarder to generate a new request 1354 // the forwarder to generate a new request
1196 if (r->stdhdr) 1355 if (r->stdhdr)
1197 {
1198 //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);
1199 //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);
1200 }
1201 } 1357 }
1202 } 1358 }
1203 else 1359 else
1204 NEXT (r->timeout); 1360 min_it (next, r->timeout - ev_now ());
1205 }
1206
1207 if (last_sent + send_interval <= NOW)
1208 { 1361 }
1362
1209 if (!send) 1363 if (!send)
1364 {
1365 // generate a new packet, if wise
1366
1367 if (!established)
1210 { 1368 {
1211 // generate a new packet, if wise 1369 if (vpn->dns_sndpq.empty ())
1212
1213 if (!established)
1214 { 1370 {
1215 if (vpn->dns_sndpq.empty ())
1216 {
1217 send = new dns_snd (this); 1371 send = new dns_snd (this);
1218 1372
1219 cfg.reset (THISNODE->id); 1373 cfg.reset (THISNODE->id);
1374 set_cfg ();
1220 send->gen_syn_req (cfg); 1375 send->gen_syn_req ();
1221 }
1222 } 1376 }
1223 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1377 }
1378 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1224 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1379 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1380 {
1381 if (last_sent + send_interval <= ev_now ())
1225 { 1382 {
1383 //printf ("sending data request etc.\n"); //D
1226 if (!snddq.empty ()) 1384 if (!snddq.empty ())
1227 {
1228 poll_interval = send_interval;
1229 NEXT (NOW + send_interval); 1385 min_it (next, send_interval);
1230 }
1231 1386
1232 send = new dns_snd (this); 1387 send = new dns_snd (this);
1233 send->gen_stream_req (sndseq, snddq); 1388 send->gen_stream_req (sndseq, snddq);
1234 send->timeout = NOW + last_latency * 8.; 1389 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1390 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1235 1391
1236 sndseq = (sndseq + 1) & SEQNO_MASK; 1392 sndseq = (sndseq + 1) & SEQNO_MASK;
1237 } 1393 }
1238 1394 else
1239 if (send) 1395 min_it (next, last_sent + send_interval - ev_now ());
1240 vpn->dns_sndpq.push_back (send);
1241 } 1396 }
1242 1397
1243 if (send) 1398 if (send)
1244 { 1399 vpn->dns_sndpq.push_back (send);
1245 last_sent = NOW; 1400 }
1401
1402 if (send)
1403 {
1404 last_sent = ev_now ();
1246 sendto (vpn->dnsv4_fd, 1405 sendto (vpn->dnsv4_fd,
1247 send->pkt->at (0), send->pkt->len, 0, 1406 send->pkt->at (0), send->pkt->len, 0,
1248 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1407 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1249 }
1250 } 1408 }
1251 else
1252 NEXT (last_sent + send_interval);
1253 1409
1410 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1411
1254 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1412 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1255 poll_interval, send_interval, next - NOW, 1413 poll_interval, send_interval, next - ev_now (),
1256 vpn->dns_sndpq.size (), snddq.size ()); 1414 vpn->dns_sndpq.size (), snddq.size (),
1257 1415 rcvpq.size ());
1258 // TODO: no idea when this happens, but when next < NOW, we have a problem
1259 if (next < NOW + 0.0001)
1260 next = NOW + 0.1;
1261 1416
1262 w.start (next); 1417 w.start (next);
1263} 1418}
1264 1419
1265#endif 1420#endif

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines