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 1.55 by root, Tue Oct 18 11:11:32 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 {
406 if (fill < 2)
407 return 0;
408
361 unsigned int len = (data [0] << 8) | data [1]; 409 len = (data [0] << 8) | data [1];
362 410
363 if (len > MAXSIZE && fill >= 2) 411 if (len <= MAXSIZE)
364 assert (len <= MAXSIZE || fill < 2); // TODO handle this gracefully, connection reset 412 break;
365 413
414 // TODO: handle this better than skipping, e.g. by reset
415 slog (L_DEBUG, _("DNS: corrupted packet (%02x %02x) stream skipping a byte..."), data [0], data [1]);
416 remove (1);
417 }
418
366 if (fill < len + 2) 419 if (fill < len + 2)
367 return 0; 420 return 0;
368 421
369 vpn_packet *pkt = new vpn_packet; 422 vpn_packet *pkt = new vpn_packet;
370 423
… …
398 451
399struct dns_cfg 452struct dns_cfg
400{ 453{
401 static int next_uid; 454 static int next_uid;
402 455
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
403 u8 id1, id2, id3, id4; 464 u8 id1, id2, id3, id4;
404 u8 version; 465
405 u8 rrtype; 466 u16 client;
406 u8 flags;
407 u8 def_ttl; 467 u8 def_ttl;
408 u8 rcv_cdc; 468 u8 r0;
409 u8 snd_cdc;
410 u16 max_size;
411 u16 client;
412 u16 uid; // to make request unique
413 469
414 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;
415 476
416 void reset (int clientid); 477 void reset (int clientid);
417 bool valid (); 478 bool valid ();
479 u8 get_chksum ();
418}; 480};
419 481
420int dns_cfg::next_uid; 482int dns_cfg::next_uid;
421 483
484void
422void dns_cfg::reset (int clientid) 485dns_cfg::reset (int clientid)
423{ 486{
487 // this ID must result in some mixed-case characters in cdc26-encoding
424 id1 = 'G'; 488 id1 = 'G';
425 id2 = 'V'; 489 id2 = 'V';
426 id3 = 'P'; 490 id3 = 'P';
427 id4 = 'E'; 491 id4 = 'E';
428 492
429 version = 1; 493 version = 2;
430 494
431 rrtype = RR_TYPE_TXT; 495 rrtype = RR_TYPE_TXT;
432 flags = 0; 496 flags = 0;
433 def_ttl = 1; 497 def_ttl = 0;
434 rcv_cdc = 0;
435 snd_cdc = 62; 498 syn_cdc = 26;
499 hdr_cdc = 36;
500 req_cdc = conf.dns_case_preserving ? 62 : 36;
501 rep_cdc = 0;
436 max_size = ntohs (MAX_PKT_SIZE); 502 max_size = htons (MAX_PKT_SIZE);
437 client = ntohs (clientid); 503 client = htons (clientid);
438 uid = next_uid++; 504 uid = ++next_uid;
439 505
440 memset (reserved, 0, 8); 506 r0 = r1 = r2 = r3 = r4 = 0;
441}
442 507
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
443bool dns_cfg::valid () 529dns_cfg::valid ()
444{ 530{
531 // although the protocol itself allows for some configurability,
532 // only the following encoding/decoding settings are implemented.
445 return id1 == 'G' 533 return id1 == 'G'
446 && id2 == 'V' 534 && id2 == 'V'
447 && id3 == 'P' 535 && id3 == 'P'
448 && id4 == 'E' 536 && id4 == 'E'
449 && version == 1 537 && version == 2
450 && flags == 0
451 && rcv_cdc == 0
452 && snd_cdc == 62 538 && syn_cdc == 26
453 && 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 ();
454} 543}
455 544
456struct dns_packet : net_packet 545struct dns_packet : net_packet
457{ 546{
458 u16 id; 547 u16 id;
459 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
460 u16 qdcount, ancount, nscount, arcount; 549 u16 qdcount, ancount, nscount, arcount;
461 550
462 u8 data[MAXSIZE - 6 * 2]; 551 u8 data [MAXSIZE - 6 * 2];
463 552
464 int decode_label (char *data, int size, int &offs); 553 int decode_label (char *data, int size, int &offs);
465}; 554};
466 555
556int
467int dns_packet::decode_label (char *data, int size, int &offs) 557dns_packet::decode_label (char *data, int size, int &offs)
468{ 558{
469 char *orig = data; 559 char *orig = data;
470 560
471 memset (data, 0, size); 561 memset (data, 0, size);
472 562
… …
498 return data - orig; 588 return data - orig;
499} 589}
500 590
501///////////////////////////////////////////////////////////////////////////// 591/////////////////////////////////////////////////////////////////////////////
502 592
593static
594u16 next_id ()
595{
596 static u16 dns_id = 0; // TODO: should be per-vpn
597
598#if 1
599 if (!dns_id)
600 dns_id = time (0);
601
602 // the simplest lsfr with periodicity 65535 i could find
603 dns_id = (dns_id << 1)
604 | (((dns_id >> 1)
605 ^ (dns_id >> 2)
606 ^ (dns_id >> 4)
607 ^ (dns_id >> 15)) & 1);
608
609 return dns_id;
610#else
611 dns_id++;//D
612
613 return htons (dns_id);
614#endif
615}
616
617struct dns_rcv;
618struct dns_snd;
619
620struct dns_connection
621{
622 connection *c;
623 struct vpn *vpn;
624
625 dns_cfg cfg;
626
627 bool established;
628 const basecoder *cdc;
629
630 tstamp last_received;
631 tstamp last_sent;
632 double min_latency;
633 double poll_interval, send_interval;
634
635 vector<dns_rcv *> rcvpq;
636
637 byte_stream rcvdq; int rcvseq; int repseq;
638 byte_stream snddq; int sndseq;
639
640 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
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
645
646 dns_connection (connection *c);
647 ~dns_connection ();
648};
649
503struct dns_snd 650struct dns_snd
504{ 651{
505 dns_packet *pkt; 652 dns_packet *pkt;
506 tstamp timeout, sent; 653 tstamp timeout, sent;
507 int retry; 654 int retry;
508 struct dns_connection *dns; 655 struct dns_connection *dns;
509 int seqno; 656 int seqno;
510 bool stdhdr; 657 bool stdhdr;
511 658
512 void gen_stream_req (int seqno, byte_stream &stream); 659 void gen_stream_req (int seqno, byte_stream &stream);
513 void gen_syn_req (const dns_cfg &cfg); 660 void gen_syn_req ();
514 661
515 dns_snd (dns_connection *dns); 662 dns_snd (dns_connection *dns);
516 ~dns_snd (); 663 ~dns_snd ();
517}; 664};
518 665
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) 666dns_snd::dns_snd (dns_connection *dns)
534: dns (dns) 667: dns (dns)
535{ 668{
536 timeout = 0; 669 timeout = 0;
537 retry = 0; 670 retry = 0;
538 seqno = 0; 671 seqno = 0;
539 sent = NOW; 672 sent = ev_now ();
540 stdhdr = false; 673 stdhdr = false;
541 674
542 pkt = new dns_packet; 675 pkt = new dns_packet;
543 676
544 pkt->id = next_id (); 677 pkt->id = next_id ();
… …
547dns_snd::~dns_snd () 680dns_snd::~dns_snd ()
548{ 681{
549 delete pkt; 682 delete pkt;
550} 683}
551 684
685static void
552static void append_domain (dns_packet &pkt, int &offs, const char *domain) 686append_domain (dns_packet &pkt, int &offs, const char *domain)
553{ 687{
554 // add tunnel domain 688 // add tunnel domain
555 for (;;) 689 for (;;)
556 { 690 {
557 const char *end = strchr (domain, '.'); 691 const char *end = strchr (domain, '.');
… …
570 704
571 domain = end + 1; 705 domain = end + 1;
572 } 706 }
573} 707}
574 708
709void
575void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 710dns_snd::gen_stream_req (int seqno, byte_stream &stream)
576{ 711{
577 stdhdr = true; 712 stdhdr = true;
578 this->seqno = seqno; 713 this->seqno = seqno;
579 714
580 timeout = NOW + INITIAL_TIMEOUT; 715 timeout = ev_now () + INITIAL_TIMEOUT;
581 716
582 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 717 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
583 pkt->qdcount = htons (1); 718 pkt->qdcount = htons (1);
584 719
585 int offs = 6*2; 720 int offs = 6*2;
586 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 721 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, 722 // 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 723 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
589 724
590 char enc[256], *encp = enc; 725 char enc[256], *encp = enc;
591 encode_header (enc, THISNODE->id, seqno); 726 encode_header (enc, THISNODE->id, seqno);
592 727
593 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);
594 729
595 if (datalen > stream.size ()) 730 if (datalen > stream.size ())
596 datalen = stream.size (); 731 datalen = stream.size ();
597 732
598 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 733 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
599 stream.remove (datalen); 734 stream.remove (datalen);
600 735
601 while (enclen) 736 while (enclen)
602 { 737 {
603 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 738 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
609 encp += lbllen; 744 encp += lbllen;
610 745
611 enclen -= lbllen; 746 enclen -= lbllen;
612 } 747 }
613 748
614 append_domain (*pkt, offs, THISNODE->domain); 749 append_domain (*pkt, offs, dns->c->conf->domain);
615 750
616 (*pkt)[offs++] = 0; 751 (*pkt)[offs++] = 0;
617 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 752 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
618 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 753 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
619 754
620 pkt->len = offs; 755 pkt->len = offs;
621} 756}
622 757
623void dns_snd::gen_syn_req (const dns_cfg &cfg) 758void
759dns_snd::gen_syn_req ()
624{ 760{
625 timeout = NOW + INITIAL_SYN_TIMEOUT; 761 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
626 762
627 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 763 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
628 pkt->qdcount = htons (1); 764 pkt->qdcount = htons (1);
629 765
630 int offs = 6*2; 766 int offs = 6 * 2;
631 767
632 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); 768 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg));
633 769
634 assert (elen <= MAX_LBL_SIZE); 770 assert (elen <= MAX_LBL_SIZE);
635 771
636 (*pkt)[offs] = elen; 772 (*pkt)[offs] = elen;
637 offs += elen + 1; 773 offs += elen + 1;
638 append_domain (*pkt, offs, THISNODE->domain); 774 append_domain (*pkt, offs, dns->c->conf->domain);
639 775
640 (*pkt)[offs++] = 0; 776 (*pkt)[offs++] = 0;
641 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 777 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
642 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 778 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
643 779
… …
666 delete pkt; 802 delete pkt;
667} 803}
668 804
669///////////////////////////////////////////////////////////////////////////// 805/////////////////////////////////////////////////////////////////////////////
670 806
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) 807dns_connection::dns_connection (connection *c)
698: c (c) 808: c (c)
699, rcvdq (MAX_BACKLOG * 2) 809, rcvdq (MAX_BACKLOG * 2)
700, snddq (MAX_BACKLOG * 2) 810, snddq (MAX_BACKLOG)
701, tw (this, &dns_connection::time_cb)
702{ 811{
812 tw.set<dns_connection, &dns_connection::time_cb> (this);
813
703 vpn = c->vpn; 814 vpn = c->vpn;
704 815
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
705 established = false; 840 established = false;
706 841
707 rcvseq = sndseq = 0; 842 rcvseq = repseq = sndseq = 0;
708 843
709 last_sent = last_received = 0; 844 last_sent = 0;
710 poll_interval = MIN_POLL_INTERVAL; 845 poll_interval = 0.5; // starting here
711 send_interval = 0.5; // starting rate 846 send_interval = 0.5; // starting rate
712 last_latency = INITIAL_TIMEOUT; 847 min_latency = INITIAL_TIMEOUT;
713} 848}
714 849
715dns_connection::~dns_connection () 850void
851dns_connection::set_cfg ()
716{ 852{
717 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 853 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
718 i != rcvpq.end ();
719 ++i)
720 delete *i;
721} 854}
722 855
856void
723void dns_connection::receive_rep (dns_rcv *r) 857dns_connection::receive_rep (dns_rcv *r)
724{ 858{
725 if (r->datalen) 859 if (r->datalen)
726 { 860 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 861 else
733 { 862 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 }
738 863
739 rcvpq.push_back (r); 864 rcvpq.push_back (r);
740 865
741 redo: 866 redo:
742 867
743 // find next packet 868 // find next packet
744 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 869 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
745 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 870 if (SEQNO_EQ (rcvseq, (*i)->seqno))
746 { 871 {
872 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
747 // enter the packet into our input stream 873 // enter the packet into our input stream
748 r = *i; 874 r = *i;
749 875
750 // remove the oldest packet, look forward, as it's oldest first 876 // remove the oldest packet, look forward, as it's oldest first
751 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)
752 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 878 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
753 { 879 {
880 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
754 delete *j; 881 delete *j;
755 rcvpq.erase (j); 882 rcvpq.erase (j);
756 break; 883 break;
757 } 884 }
758 885
759 rcvseq = (rcvseq + 1) & SEQNO_MASK; 886 rcvseq = (rcvseq + 1) & SEQNO_MASK;
760 887
761 if (!rcvdq.put (r->data, r->datalen)) 888 if (!rcvdq.put (r->data, r->datalen))
762 { 889 {
890 // MUST never overflow, can be caused by data corruption, TODO
763 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 891 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
764 abort (); // MUST never overflow, can be caused by data corruption, TODO 892 reset ();
893 return;
765 } 894 }
766 895
767 while (vpn_packet *pkt = rcvdq.get ()) 896 while (vpn_packet *pkt = rcvdq.get ())
768 { 897 {
769 sockinfo si; 898 sockinfo si;
770 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 899 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
771 900
772 vpn->recv_vpn_packet (pkt, si); 901 vpn->recv_vpn_packet (pkt, si);
773
774 delete pkt; 902 delete pkt;
775 } 903 }
776 904
777 // check for further packets 905 // check for further packets
778 goto redo; 906 goto redo;
… …
789 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 917 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
790 918
791 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 919 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
792 && pkt.qdcount == htons (1)) 920 && pkt.qdcount == htons (1))
793 { 921 {
794 char qname[MAXSIZE]; 922 char qname [MAXSIZE];
795 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 923 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
796 924
797 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 925 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
798 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 926 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
799 927
… …
806 934
807 int dlen = strlen (THISNODE->domain); 935 int dlen = strlen (THISNODE->domain);
808 936
809 if (qclass == RR_CLASS_IN 937 if (qclass == RR_CLASS_IN
810 && qlen > dlen + 1 938 && qlen > dlen + 1
811 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 939 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
812 { 940 {
813 // now generate reply 941 // now generate reply
814 pkt.ancount = htons (1); // one answer RR 942 pkt.ancount = htons (1); // one answer RR
815 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 943 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
816 944
… …
821 { 949 {
822 // correct class, domain: parse 950 // correct class, domain: parse
823 int client, seqno; 951 int client, seqno;
824 decode_header (qname, client, seqno); 952 decode_header (qname, client, seqno);
825 953
826 u8 data[MAXSIZE];
827 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
828
829 if (0 < client && client <= conns.size ()) 954 if (0 < client && client <= conns.size ())
830 { 955 {
831 connection *c = conns [client - 1]; 956 connection *c = conns [client - 1];
832 dns_connection *dns = c->dns; 957 dns_connection *dns = c->dns;
833 dns_rcv *rcv; 958 dns_rcv *rcv;
834 bool in_seq;
835 959
836 if (dns) 960 if (dns)
837 { 961 {
962 u8 data[MAXSIZE];
963 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
964
838 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 (); )
839 if (SEQNO_EQ ((*i)->seqno, seqno)) 966 if (SEQNO_EQ ((*i)->seqno, seqno))
840 { 967 {
841 // already seen that request: simply reply with the cached reply 968 // already seen that request: simply reply with the cached reply
842 dns_rcv *r = *i; 969 dns_rcv *r = *i;
… …
850 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);
851 978
852 goto duplicate_request; 979 goto duplicate_request;
853 } 980 }
854 981
855 in_seq = dns->rcvseq == seqno;
856
857 // new packet, queue 982 // new packet, queue
858 rcv = new dns_rcv (seqno, data, datalen); 983 rcv = new dns_rcv (seqno, data, datalen);
859 dns->receive_rep (rcv); 984 dns->receive_rep (rcv);
860 } 985 }
861 986
987 {
862 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
863 989
864 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 990 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
865 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 991 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
866 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
867 pkt [offs++] = 0; pkt [offs++] = 0; 993 pkt [offs++] = 0; pkt [offs++] = 0;
868 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
869 995
870 int rdlen_offs = offs += 2; 996 int rdlen_offs = offs += 2;
871 997
998 if (dns)
999 {
872 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 1000 int dlen = ntohs (dns->cfg.max_size) - offs;
1001
873 // 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
874 dlen -= qlen; 1003 dlen -= qlen;
875 1004
876 if (dns)
877 {
878 // only put data into in-order sequence packets, if 1005 // only put data into in-order sequence packets, if
879 // we receive out-of-order packets we generate empty 1006 // we receive out-of-order packets we generate empty
880 // replies 1007 // replies
881 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)
882 { 1010 {
1011 dns->repseq = seqno;
1012
1013 while (dlen > 1 && !dns->snddq.empty ())
1014 {
883 int txtlen = dlen <= 255 ? dlen - 1 : 255; 1015 int txtlen = dlen <= 255 ? dlen - 1 : 255;
884 1016
885 if (txtlen > dns->snddq.size ()) 1017 if (txtlen > dns->snddq.size ())
886 txtlen = dns->snddq.size (); 1018 txtlen = dns->snddq.size ();
887 1019
888 pkt[offs++] = txtlen; 1020 pkt[offs++] = txtlen;
889 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 1021 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
890 offs += txtlen; 1022 offs += txtlen;
891 dns->snddq.remove (txtlen); 1023 dns->snddq.remove (txtlen);
892 1024
893 dlen -= txtlen + 1; 1025 dlen -= txtlen + 1;
1026 }
894 } 1027 }
895 1028
896 // avoid empty TXT rdata 1029 // avoid completely empty TXT rdata
897 if (offs == rdlen_offs) 1030 if (offs == rdlen_offs)
898 pkt[offs++] = 0; 1031 pkt[offs++] = 0;
899 1032
900 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 1033 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
901 } 1034 }
902 else 1035 else
903 { 1036 {
904 // send RST 1037 // send RST
905 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;
906 pkt [offs++] = CMD_IP_RST; 1039 pkt [offs++] = CMD_IP_RST;
907 } 1040 }
908 1041
909 int rdlen = offs - rdlen_offs; 1042 int rdlen = offs - rdlen_offs;
910 1043
911 pkt [rdlen_offs - 2] = rdlen >> 8; 1044 pkt [rdlen_offs - 2] = rdlen >> 8;
912 pkt [rdlen_offs - 1] = rdlen; 1045 pkt [rdlen_offs - 1] = rdlen;
913 1046
914 if (dns) 1047 if (dns)
915 { 1048 {
916 // now update dns_rcv copy 1049 // now update dns_rcv copy
917 rcv->pkt->len = offs; 1050 rcv->pkt->len = offs;
918 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 1051 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
919 } 1052 }
1053 }
920 1054
921 duplicate_request: ; 1055 duplicate_request: ;
922 } 1056 }
923 else 1057 else
924 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 1058 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
936 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
937 pkt [offs++] = 0; pkt [offs++] = 0; 1071 pkt [offs++] = 0; pkt [offs++] = 0;
938 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1072 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
939 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1073 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
940 1074
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; 1075 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
944 pkt [offs++] = CMD_IP_REJ; 1076 pkt [offs++] = CMD_IP_REJ;
945 1077
946 if (0 < client && client <= conns.size ()) 1078 if (0 < client && client <= conns.size ())
947 { 1079 {
948 connection *c = conns [client - 1]; 1080 connection *c = conns [client - 1];
949 1081
950 if (cfg.valid ()) 1082 if (cfg.valid ())
951 { 1083 {
952 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));
953 1089
954 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
955 c->dns = new dns_connection (c); 1095 c->dns = new dns_connection (c);
956 c->dns->cfg = cfg; 1096 c->dns->cfg = cfg;
1097 c->dns->set_cfg ();
957 } 1098 }
958 } 1099 }
959 } 1100 }
960 } 1101 }
961 1102
… …
980 { 1121 {
981 dns_connection *dns = (*i)->dns; 1122 dns_connection *dns = (*i)->dns;
982 connection *c = dns->c; 1123 connection *c = dns->c;
983 int seqno = (*i)->seqno; 1124 int seqno = (*i)->seqno;
984 u8 data[MAXSIZE], *datap = data; 1125 u8 data[MAXSIZE], *datap = data;
1126 //printf ("rcv pkt %x\n", seqno);//D
985 1127
986 if ((*i)->retry) 1128 if ((*i)->retry)
987 { 1129 {
988 dns->send_interval *= 1.01; 1130 dns->send_interval *= 1.01;
989 if (dns->send_interval > MAX_SEND_INTERVAL) 1131 if (dns->send_interval > MAX_SEND_INTERVAL)
990 dns->send_interval = MAX_SEND_INTERVAL; 1132 dns->send_interval = MAX_SEND_INTERVAL;
991 } 1133 }
992 else 1134 else
993 { 1135 {
994#if 1 1136#if 0
995 dns->send_interval *= 0.999; 1137 dns->send_interval *= 0.999;
996#endif 1138#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 1139 // the latency surely puts an upper bound on
1001 // the minimum send interval 1140 // the minimum send interval
1002 double latency = NOW - (*i)->sent; 1141 double latency = ev_now () - (*i)->sent;
1142
1143 if (latency < dns->min_latency)
1003 dns->last_latency = latency; 1144 dns->min_latency = latency;
1004 1145
1005 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)
1006 dns->send_interval = latency; 1150 dns->send_interval = conf.dns_send_interval;
1007 } 1151 }
1008 1152
1009 delete *i; 1153 delete *i;
1010 dns_sndpq.erase (i); 1154 dns_sndpq.erase (i);
1011 1155
… …
1029 ttl |= pkt [offs++] << 16; 1173 ttl |= pkt [offs++] << 16;
1030 ttl |= pkt [offs++] << 8; 1174 ttl |= pkt [offs++] << 8;
1031 ttl |= pkt [offs++]; 1175 ttl |= pkt [offs++];
1032 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1176 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1033 1177
1034 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1178 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1035 { 1179 {
1036 if (rdlen <= MAXSIZE - offs) 1180 if (rdlen <= MAXSIZE - offs)
1037 { 1181 {
1038 // decode bytes, finally 1182 // decode bytes, finally
1039 1183
… …
1065 { 1209 {
1066 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1210 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1067 1211
1068 if (ip [3] == CMD_IP_RST) 1212 if (ip [3] == CMD_IP_RST)
1069 { 1213 {
1070 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1214 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1071 1215
1072 delete dns; c->dns = 0; 1216 dns->reset ();
1073
1074 return; 1217 return;
1075 } 1218 }
1076 else if (ip [3] == CMD_IP_SYN) 1219 else if (ip [3] == CMD_IP_SYN)
1077 { 1220 {
1078 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1221 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1079 dns->established = true; 1222 dns->established = true;
1080 } 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 }
1081 else if (ip [3] == CMD_IP_REJ) 1239 else if (ip [3] == CMD_IP_REJ)
1082 { 1240 {
1083 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."));
1084 abort (); 1242 dns->tw.start (60.);
1085 } 1243 }
1086 else 1244 else
1245 {
1087 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 }
1088 } 1249 }
1089 else 1250 else
1090 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"),
1091 ip [0], ip [1], ip [2], ip [3]); 1252 ip [0], ip [1], ip [2], ip [3]);
1092 1253
… …
1116 break; 1277 break;
1117 } 1278 }
1118} 1279}
1119 1280
1120void 1281void
1121vpn::dnsv4_ev (io_watcher &w, short revents) 1282vpn::dnsv4_ev (ev::io &w, int revents)
1122{ 1283{
1123 if (revents & EVENT_READ) 1284 if (revents & EV_READ)
1124 { 1285 {
1125 dns_packet *pkt = new dns_packet; 1286 dns_packet *pkt = new dns_packet;
1126 struct sockaddr_in sa; 1287 struct sockaddr_in sa;
1127 socklen_t sa_len = sizeof (sa); 1288 socklen_t sa_len = sizeof (sa);
1128 1289
1129 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);
1130 1291
1131 if (pkt->len > 0) 1292 if (pkt->len > 0)
1132 { 1293 {
1133 if (THISNODE->dns_port) 1294 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1295 dnsv4_client (*pkt);
1296 else
1134 { 1297 {
1135 dnsv4_server (*pkt); 1298 dnsv4_server (*pkt);
1136 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);
1137 } 1300 }
1138 else
1139 dnsv4_client (*pkt);
1140 1301
1141 delete pkt; 1302 delete pkt;
1142 } 1303 }
1143 } 1304 }
1144} 1305}
1145 1306
1146bool 1307bool
1147connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1308vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1148{ 1309{
1310 int client = ntohl (si.host);
1311
1312 assert (0 < client && client <= conns.size ());
1313
1314 connection *c = conns [client - 1];
1315
1149 if (!dns) 1316 if (!c->dns)
1150 dns = new dns_connection (this); 1317 c->dns = new dns_connection (c);
1151 1318
1152 if (!dns->snddq.put (pkt)) 1319 if (c->dns->snddq.put (pkt))
1153 return false; 1320 {
1321 min_it (c->dns->poll_interval, 0.25);
1322 c->dns->tw ();
1323 }
1154 1324
1155 dns->tw.trigger (); 1325 // always return true even if the buffer overflows
1156
1157 return true; 1326 return true;
1158} 1327}
1159 1328
1160void 1329void
1161connection::dnsv4_reset_connection () 1330dns_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{ 1331{
1171 // servers have to be polled 1332 // servers have to be polled
1172 if (THISNODE->dns_port) 1333 if (THISNODE->dns_port)
1173 return; 1334 return;
1174 1335
1175 // check for timeouts and (re)transmit 1336 // check for timeouts and (re)transmit
1176 tstamp next = NOW + poll_interval; 1337 tstamp next = 86400 * 365;
1177 dns_snd *send = 0; 1338 dns_snd *send = 0;
1178 1339
1179 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1340 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1180 i != vpn->dns_sndpq.end (); 1341 i != vpn->dns_sndpq.end ();
1181 ++i) 1342 ++i)
1182 { 1343 {
1183 dns_snd *r = *i; 1344 dns_snd *r = *i;
1184 1345
1185 if (r->timeout <= NOW) 1346 if (r->timeout <= ev_now ())
1186 { 1347 {
1187 if (!send) 1348 if (!send)
1188 { 1349 {
1189 send = r; 1350 send = r;
1190 1351
1191 r->retry++; 1352 r->retry++;
1192 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
1193 1355
1194 // the following code changes the query section a bit, forcing 1356 // the following code changes the query section a bit, forcing
1195 // the forwarder to generate a new request 1357 // the forwarder to generate a new request
1196 if (r->stdhdr) 1358 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); 1359 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1200 }
1201 } 1360 }
1202 } 1361 }
1203 else 1362 else
1204 NEXT (r->timeout); 1363 min_it (next, r->timeout - ev_now ());
1205 }
1206
1207 if (last_sent + send_interval <= NOW)
1208 { 1364 }
1365
1209 if (!send) 1366 if (!send)
1367 {
1368 // generate a new packet, if wise
1369
1370 if (!established)
1210 { 1371 {
1211 // generate a new packet, if wise 1372 if (vpn->dns_sndpq.empty ())
1212
1213 if (!established)
1214 { 1373 {
1215 if (vpn->dns_sndpq.empty ())
1216 {
1217 send = new dns_snd (this); 1374 send = new dns_snd (this);
1218 1375
1219 cfg.reset (THISNODE->id); 1376 cfg.reset (THISNODE->id);
1377 set_cfg ();
1220 send->gen_syn_req (cfg); 1378 send->gen_syn_req ();
1221 }
1222 } 1379 }
1223 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1380 }
1381 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1224 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1382 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1383 {
1384 if (last_sent + send_interval <= ev_now ())
1225 { 1385 {
1386 //printf ("sending data request etc.\n"); //D
1226 if (!snddq.empty ()) 1387 if (!snddq.empty ())
1227 {
1228 poll_interval = send_interval;
1229 NEXT (NOW + send_interval); 1388 min_it (next, send_interval);
1230 }
1231 1389
1232 send = new dns_snd (this); 1390 send = new dns_snd (this);
1233 send->gen_stream_req (sndseq, snddq); 1391 send->gen_stream_req (sndseq, snddq);
1234 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
1235 1394
1236 sndseq = (sndseq + 1) & SEQNO_MASK; 1395 sndseq = (sndseq + 1) & SEQNO_MASK;
1237 } 1396 }
1238 1397 else
1239 if (send) 1398 min_it (next, last_sent + send_interval - ev_now ());
1240 vpn->dns_sndpq.push_back (send);
1241 } 1399 }
1242 1400
1243 if (send) 1401 if (send)
1244 { 1402 vpn->dns_sndpq.push_back (send);
1245 last_sent = NOW; 1403 }
1404
1405 if (send)
1406 {
1407 last_sent = ev_now ();
1246 sendto (vpn->dnsv4_fd, 1408 sendto (vpn->dnsv4_fd,
1247 send->pkt->at (0), send->pkt->len, 0, 1409 send->pkt->at (0), send->pkt->len, 0,
1248 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1410 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1249 }
1250 } 1411 }
1251 else
1252 NEXT (last_sent + send_interval);
1253 1412
1413 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1414
1254 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)",
1255 poll_interval, send_interval, next - NOW, 1416 poll_interval, send_interval, next - ev_now (),
1256 vpn->dns_sndpq.size (), snddq.size ()); 1417 vpn->dns_sndpq.size (), snddq.size (),
1257 1418 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 1419
1262 w.start (next); 1420 w.start (next);
1263} 1421}
1264 1422
1265#endif 1423#endif

Diff Legend

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