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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.17 by pcg, Sat Mar 5 03:47:05 2005 UTC vs.
Revision 1.52 by root, Sun Mar 6 21:01:37 2011 UTC

1/* 1/*
2 vpn_dns.C -- handle the dns tunnel part of the protocol. 2 vpn_dns.C -- handle the dns tunnel part of the protocol.
3 Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de> 3 Copyright (C) 2003-2011 Marc Lehmann <gvpe@schmorp.de>
4 4
5 This file is part of GVPE. 5 This file is part of GVPE.
6 6
7 GVPE is free software; you can redistribute it and/or modify 7 GVPE is free software; you can redistribute it and/or modify it
8 it under the terms of the GNU General Public License as published by 8 under the terms of the GNU General Public License as published by the
9 the Free Software Foundation; either version 2 of the License, or 9 Free Software Foundation; either version 3 of the License, or (at your
10 (at your option) any later version. 10 option) any later version.
11 11
12 This program is distributed in the hope that it will be useful, 12 This program is distributed in the hope that it will be useful, but
13 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15 GNU General Public License for more details. 15 Public License for more details.
16 16
17 You should have received a copy of the GNU General Public License 17 You should have received a copy of the GNU General Public License along
18 along with gvpe; if not, write to the Free Software 18 with this program; if not, see <http://www.gnu.org/licenses/>.
19 Foundation, Inc. 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 240 // 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 (!dns_id)
596 dns_id = time (0);
597
598 // the simplest lsfr with periodicity 65535 i could find
599 dns_id = (dns_id << 1)
600 | (((dns_id >> 1)
601 ^ (dns_id >> 2)
602 ^ (dns_id >> 4)
603 ^ (dns_id >> 15)) & 1);
604
605 return dns_id;
606}
607
608struct dns_rcv;
609struct dns_snd;
610
611struct dns_connection
612{
613 connection *c;
614 struct vpn *vpn;
615
616 dns_cfg cfg;
617
618 bool established;
619 const basecoder *cdc;
620
621 tstamp last_received;
622 tstamp last_sent;
623 double min_latency;
624 double poll_interval, send_interval;
625
626 vector<dns_rcv *> rcvpq;
627
628 byte_stream rcvdq; int rcvseq; int repseq;
629 byte_stream snddq; int sndseq;
630
631 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
632 void receive_rep (dns_rcv *r);
633
634 void reset (); // quite like tcp RST
635 void set_cfg (); // to be called after any cfg changes
636
637 dns_connection (connection *c);
638 ~dns_connection ();
639};
640
503struct dns_snd 641struct dns_snd
504{ 642{
505 dns_packet *pkt; 643 dns_packet *pkt;
506 tstamp timeout, sent; 644 tstamp timeout, sent;
507 int retry; 645 int retry;
508 struct dns_connection *dns; 646 struct dns_connection *dns;
509 int seqno; 647 int seqno;
510 bool stdhdr; 648 bool stdhdr;
511 649
512 void gen_stream_req (int seqno, byte_stream &stream); 650 void gen_stream_req (int seqno, byte_stream &stream);
513 void gen_syn_req (const dns_cfg &cfg); 651 void gen_syn_req ();
514 652
515 dns_snd (dns_connection *dns); 653 dns_snd (dns_connection *dns);
516 ~dns_snd (); 654 ~dns_snd ();
517}; 655};
518 656
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) 657dns_snd::dns_snd (dns_connection *dns)
534: dns (dns) 658: dns (dns)
535{ 659{
536 timeout = 0; 660 timeout = 0;
537 retry = 0; 661 retry = 0;
538 seqno = 0; 662 seqno = 0;
539 sent = NOW; 663 sent = ev_now ();
540 stdhdr = false; 664 stdhdr = false;
541 665
542 pkt = new dns_packet; 666 pkt = new dns_packet;
543 667
544 pkt->id = next_id (); 668 pkt->id = next_id ();
… …
547dns_snd::~dns_snd () 671dns_snd::~dns_snd ()
548{ 672{
549 delete pkt; 673 delete pkt;
550} 674}
551 675
676static void
552static void append_domain (dns_packet &pkt, int &offs, const char *domain) 677append_domain (dns_packet &pkt, int &offs, const char *domain)
553{ 678{
554 // add tunnel domain 679 // add tunnel domain
555 for (;;) 680 for (;;)
556 { 681 {
557 const char *end = strchr (domain, '.'); 682 const char *end = strchr (domain, '.');
… …
570 695
571 domain = end + 1; 696 domain = end + 1;
572 } 697 }
573} 698}
574 699
700void
575void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 701dns_snd::gen_stream_req (int seqno, byte_stream &stream)
576{ 702{
577 stdhdr = true; 703 stdhdr = true;
578 this->seqno = seqno; 704 this->seqno = seqno;
579 705
580 timeout = NOW + INITIAL_TIMEOUT; 706 timeout = ev_now () + INITIAL_TIMEOUT;
581 707
582 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 708 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
583 pkt->qdcount = htons (1); 709 pkt->qdcount = htons (1);
584 710
585 int offs = 6*2; 711 int offs = 6*2;
586 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 712 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, 713 // 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 714 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
589 715
590 char enc[256], *encp = enc; 716 char enc[256], *encp = enc;
591 encode_header (enc, THISNODE->id, seqno); 717 encode_header (enc, THISNODE->id, seqno);
592 718
593 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 719 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
594 720
595 if (datalen > stream.size ()) 721 if (datalen > stream.size ())
596 datalen = stream.size (); 722 datalen = stream.size ();
597 723
598 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 724 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
599 stream.remove (datalen); 725 stream.remove (datalen);
600 726
601 while (enclen) 727 while (enclen)
602 { 728 {
603 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 729 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
609 encp += lbllen; 735 encp += lbllen;
610 736
611 enclen -= lbllen; 737 enclen -= lbllen;
612 } 738 }
613 739
614 append_domain (*pkt, offs, THISNODE->domain); 740 append_domain (*pkt, offs, dns->c->conf->domain);
615 741
616 (*pkt)[offs++] = 0; 742 (*pkt)[offs++] = 0;
617 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 743 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
618 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 744 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
619 745
620 pkt->len = offs; 746 pkt->len = offs;
621} 747}
622 748
623void dns_snd::gen_syn_req (const dns_cfg &cfg) 749void
750dns_snd::gen_syn_req ()
624{ 751{
625 timeout = NOW + INITIAL_SYN_TIMEOUT; 752 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
626 753
627 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 754 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
628 pkt->qdcount = htons (1); 755 pkt->qdcount = htons (1);
629 756
630 int offs = 6*2; 757 int offs = 6 * 2;
631 758
632 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); 759 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg));
633 760
634 assert (elen <= MAX_LBL_SIZE); 761 assert (elen <= MAX_LBL_SIZE);
635 762
636 (*pkt)[offs] = elen; 763 (*pkt)[offs] = elen;
637 offs += elen + 1; 764 offs += elen + 1;
638 append_domain (*pkt, offs, THISNODE->domain); 765 append_domain (*pkt, offs, dns->c->conf->domain);
639 766
640 (*pkt)[offs++] = 0; 767 (*pkt)[offs++] = 0;
641 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 768 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
642 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 769 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
643 770
… …
666 delete pkt; 793 delete pkt;
667} 794}
668 795
669///////////////////////////////////////////////////////////////////////////// 796/////////////////////////////////////////////////////////////////////////////
670 797
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) 798dns_connection::dns_connection (connection *c)
698: c (c) 799: c (c)
699, rcvdq (MAX_BACKLOG * 2) 800, rcvdq (MAX_BACKLOG * 2)
700, snddq (MAX_BACKLOG * 2) 801, snddq (MAX_BACKLOG)
701, tw (this, &dns_connection::time_cb)
702{ 802{
803 tw.set<dns_connection, &dns_connection::time_cb> (this);
804
703 vpn = c->vpn; 805 vpn = c->vpn;
704 806
807 reset ();
808}
809
810dns_connection::~dns_connection ()
811{
812 reset ();
813}
814
815void
816dns_connection::reset ()
817{
818 while (!rcvpq.empty ())
819 {
820 delete rcvpq.back ();
821 rcvpq.pop_back ();
822 }
823
824 for (int i = vpn->dns_sndpq.size (); i--; )
825 if (vpn->dns_sndpq [i]->dns == this)
826 {
827 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
828 vpn->dns_sndpq.pop_back ();
829 }
830
705 established = false; 831 established = false;
706 832
707 rcvseq = sndseq = 0; 833 rcvseq = repseq = sndseq = 0;
708 834
709 last_sent = last_received = 0; 835 last_sent = 0;
710 poll_interval = MIN_POLL_INTERVAL; 836 poll_interval = 0.5; // starting here
711 send_interval = 0.5; // starting rate 837 send_interval = 0.5; // starting rate
712 last_latency = INITIAL_TIMEOUT; 838 min_latency = INITIAL_TIMEOUT;
713} 839}
714 840
715dns_connection::~dns_connection () 841void
842dns_connection::set_cfg ()
716{ 843{
717 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 844 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
718 i != rcvpq.end ();
719 ++i)
720 delete *i;
721} 845}
722 846
847void
723void dns_connection::receive_rep (dns_rcv *r) 848dns_connection::receive_rep (dns_rcv *r)
724{ 849{
725 if (r->datalen) 850 if (r->datalen)
726 { 851 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 852 else
733 { 853 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 }
738 854
739 rcvpq.push_back (r); 855 rcvpq.push_back (r);
740 856
741 redo: 857 redo:
742 858
743 // find next packet 859 // find next packet
744 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 860 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
745 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 861 if (SEQNO_EQ (rcvseq, (*i)->seqno))
746 { 862 {
863 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
747 // enter the packet into our input stream 864 // enter the packet into our input stream
748 r = *i; 865 r = *i;
749 866
750 // remove the oldest packet, look forward, as it's oldest first 867 // remove the oldest packet, look forward, as it's oldest first
751 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 868 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
752 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 869 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
753 { 870 {
871 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
754 delete *j; 872 delete *j;
755 rcvpq.erase (j); 873 rcvpq.erase (j);
756 break; 874 break;
757 } 875 }
758 876
759 rcvseq = (rcvseq + 1) & SEQNO_MASK; 877 rcvseq = (rcvseq + 1) & SEQNO_MASK;
760 878
761 if (!rcvdq.put (r->data, r->datalen)) 879 if (!rcvdq.put (r->data, r->datalen))
762 { 880 {
881 // MUST never overflow, can be caused by data corruption, TODO
763 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 882 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
764 abort (); // MUST never overflow, can be caused by data corruption, TODO 883 reset ();
884 return;
765 } 885 }
766 886
767 while (vpn_packet *pkt = rcvdq.get ()) 887 while (vpn_packet *pkt = rcvdq.get ())
768 { 888 {
769 sockinfo si; 889 sockinfo si;
770 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 890 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
771 891
772 vpn->recv_vpn_packet (pkt, si); 892 vpn->recv_vpn_packet (pkt, si);
773
774 delete pkt; 893 delete pkt;
775 } 894 }
776 895
777 // check for further packets 896 // check for further packets
778 goto redo; 897 goto redo;
… …
789 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 908 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
790 909
791 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 910 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
792 && pkt.qdcount == htons (1)) 911 && pkt.qdcount == htons (1))
793 { 912 {
794 char qname[MAXSIZE]; 913 char qname [MAXSIZE];
795 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 914 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
796 915
797 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 916 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
798 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 917 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
799 918
… …
806 925
807 int dlen = strlen (THISNODE->domain); 926 int dlen = strlen (THISNODE->domain);
808 927
809 if (qclass == RR_CLASS_IN 928 if (qclass == RR_CLASS_IN
810 && qlen > dlen + 1 929 && qlen > dlen + 1
811 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 930 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
812 { 931 {
813 // now generate reply 932 // now generate reply
814 pkt.ancount = htons (1); // one answer RR 933 pkt.ancount = htons (1); // one answer RR
815 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 934 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
816 935
… …
821 { 940 {
822 // correct class, domain: parse 941 // correct class, domain: parse
823 int client, seqno; 942 int client, seqno;
824 decode_header (qname, client, seqno); 943 decode_header (qname, client, seqno);
825 944
826 u8 data[MAXSIZE];
827 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
828
829 if (0 < client && client <= conns.size ()) 945 if (0 < client && client <= conns.size ())
830 { 946 {
831 connection *c = conns [client - 1]; 947 connection *c = conns [client - 1];
832 dns_connection *dns = c->dns; 948 dns_connection *dns = c->dns;
833 dns_rcv *rcv; 949 dns_rcv *rcv;
834 bool in_seq;
835 950
836 if (dns) 951 if (dns)
837 { 952 {
953 u8 data[MAXSIZE];
954 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
955
838 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 956 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
839 if (SEQNO_EQ ((*i)->seqno, seqno)) 957 if (SEQNO_EQ ((*i)->seqno, seqno))
840 { 958 {
841 // already seen that request: simply reply with the cached reply 959 // already seen that request: simply reply with the cached reply
842 dns_rcv *r = *i; 960 dns_rcv *r = *i;
… …
850 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 968 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
851 969
852 goto duplicate_request; 970 goto duplicate_request;
853 } 971 }
854 972
855 in_seq = dns->rcvseq == seqno;
856
857 // new packet, queue 973 // new packet, queue
858 rcv = new dns_rcv (seqno, data, datalen); 974 rcv = new dns_rcv (seqno, data, datalen);
859 dns->receive_rep (rcv); 975 dns->receive_rep (rcv);
860 } 976 }
861 977
978 {
862 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 979 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
863 980
864 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 981 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
865 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 982 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
866 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 983 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
867 pkt [offs++] = 0; pkt [offs++] = 0; 984 pkt [offs++] = 0; pkt [offs++] = 0;
868 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 985 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
869 986
870 int rdlen_offs = offs += 2; 987 int rdlen_offs = offs += 2;
871 988
989 if (dns)
990 {
872 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 991 int dlen = ntohs (dns->cfg.max_size) - offs;
992
873 // bind doesn't compress well, so reduce further by one label length 993 // bind doesn't compress well, so reduce further by one label length
874 dlen -= qlen; 994 dlen -= qlen;
875 995
876 if (dns)
877 {
878 // only put data into in-order sequence packets, if 996 // only put data into in-order sequence packets, if
879 // we receive out-of-order packets we generate empty 997 // we receive out-of-order packets we generate empty
880 // replies 998 // replies
881 while (dlen > 1 && !dns->snddq.empty () && in_seq) 999 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
1000 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
882 { 1001 {
1002 dns->repseq = seqno;
1003
1004 while (dlen > 1 && !dns->snddq.empty ())
1005 {
883 int txtlen = dlen <= 255 ? dlen - 1 : 255; 1006 int txtlen = dlen <= 255 ? dlen - 1 : 255;
884 1007
885 if (txtlen > dns->snddq.size ()) 1008 if (txtlen > dns->snddq.size ())
886 txtlen = dns->snddq.size (); 1009 txtlen = dns->snddq.size ();
887 1010
888 pkt[offs++] = txtlen; 1011 pkt[offs++] = txtlen;
889 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 1012 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
890 offs += txtlen; 1013 offs += txtlen;
891 dns->snddq.remove (txtlen); 1014 dns->snddq.remove (txtlen);
892 1015
893 dlen -= txtlen + 1; 1016 dlen -= txtlen + 1;
1017 }
894 } 1018 }
895 1019
896 // avoid empty TXT rdata 1020 // avoid completely empty TXT rdata
897 if (offs == rdlen_offs) 1021 if (offs == rdlen_offs)
898 pkt[offs++] = 0; 1022 pkt[offs++] = 0;
899 1023
900 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 1024 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
901 } 1025 }
902 else 1026 else
903 { 1027 {
904 // send RST 1028 // send RST
905 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1029 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
906 pkt [offs++] = CMD_IP_RST; 1030 pkt [offs++] = CMD_IP_RST;
907 } 1031 }
908 1032
909 int rdlen = offs - rdlen_offs; 1033 int rdlen = offs - rdlen_offs;
910 1034
911 pkt [rdlen_offs - 2] = rdlen >> 8; 1035 pkt [rdlen_offs - 2] = rdlen >> 8;
912 pkt [rdlen_offs - 1] = rdlen; 1036 pkt [rdlen_offs - 1] = rdlen;
913 1037
914 if (dns) 1038 if (dns)
915 { 1039 {
916 // now update dns_rcv copy 1040 // now update dns_rcv copy
917 rcv->pkt->len = offs; 1041 rcv->pkt->len = offs;
918 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 1042 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
919 } 1043 }
1044 }
920 1045
921 duplicate_request: ; 1046 duplicate_request: ;
922 } 1047 }
923 else 1048 else
924 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 1049 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
936 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1061 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
937 pkt [offs++] = 0; pkt [offs++] = 0; 1062 pkt [offs++] = 0; pkt [offs++] = 0;
938 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1063 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
939 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1064 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
940 1065
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; 1066 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
944 pkt [offs++] = CMD_IP_REJ; 1067 pkt [offs++] = CMD_IP_REJ;
945 1068
946 if (0 < client && client <= conns.size ()) 1069 if (0 < client && client <= conns.size ())
947 { 1070 {
948 connection *c = conns [client - 1]; 1071 connection *c = conns [client - 1];
949 1072
950 if (cfg.valid ()) 1073 if (cfg.valid ())
951 { 1074 {
952 pkt [offs - 1] = CMD_IP_SYN; 1075 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1076
1077 // check for any encoding mismatches - hints at a case problem
1078 char qname2 [MAX_ENC_LEN];
1079 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
953 1080
954 delete c->dns; 1081 delete c->dns;
1082
1083 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1084 ? CMD_IP_CSE : CMD_IP_SYN;
1085
955 c->dns = new dns_connection (c); 1086 c->dns = new dns_connection (c);
956 c->dns->cfg = cfg; 1087 c->dns->cfg = cfg;
1088 c->dns->set_cfg ();
957 } 1089 }
958 } 1090 }
959 } 1091 }
960 } 1092 }
961 1093
… …
980 { 1112 {
981 dns_connection *dns = (*i)->dns; 1113 dns_connection *dns = (*i)->dns;
982 connection *c = dns->c; 1114 connection *c = dns->c;
983 int seqno = (*i)->seqno; 1115 int seqno = (*i)->seqno;
984 u8 data[MAXSIZE], *datap = data; 1116 u8 data[MAXSIZE], *datap = data;
1117 //printf ("rcv pkt %x\n", seqno);//D
985 1118
986 if ((*i)->retry) 1119 if ((*i)->retry)
987 { 1120 {
988 dns->send_interval *= 1.01; 1121 dns->send_interval *= 1.01;
989 if (dns->send_interval > MAX_SEND_INTERVAL) 1122 if (dns->send_interval > MAX_SEND_INTERVAL)
990 dns->send_interval = MAX_SEND_INTERVAL; 1123 dns->send_interval = MAX_SEND_INTERVAL;
991 } 1124 }
992 else 1125 else
993 { 1126 {
994#if 1 1127#if 0
995 dns->send_interval *= 0.999; 1128 dns->send_interval *= 0.999;
996#endif 1129#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 1130 // the latency surely puts an upper bound on
1001 // the minimum send interval 1131 // the minimum send interval
1002 double latency = NOW - (*i)->sent; 1132 double latency = ev_now () - (*i)->sent;
1133
1134 if (latency < dns->min_latency)
1003 dns->last_latency = latency; 1135 dns->min_latency = latency;
1004 1136
1005 if (dns->send_interval > latency) 1137 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1138 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1139
1140 if (dns->send_interval < conf.dns_send_interval)
1006 dns->send_interval = latency; 1141 dns->send_interval = conf.dns_send_interval;
1007 } 1142 }
1008 1143
1009 delete *i; 1144 delete *i;
1010 dns_sndpq.erase (i); 1145 dns_sndpq.erase (i);
1011 1146
… …
1029 ttl |= pkt [offs++] << 16; 1164 ttl |= pkt [offs++] << 16;
1030 ttl |= pkt [offs++] << 8; 1165 ttl |= pkt [offs++] << 8;
1031 ttl |= pkt [offs++]; 1166 ttl |= pkt [offs++];
1032 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1167 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1033 1168
1034 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1169 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1035 { 1170 {
1036 if (rdlen <= MAXSIZE - offs) 1171 if (rdlen <= MAXSIZE - offs)
1037 { 1172 {
1038 // decode bytes, finally 1173 // decode bytes, finally
1039 1174
… …
1065 { 1200 {
1066 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1201 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1067 1202
1068 if (ip [3] == CMD_IP_RST) 1203 if (ip [3] == CMD_IP_RST)
1069 { 1204 {
1070 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1205 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1071 1206
1072 delete dns; c->dns = 0; 1207 dns->reset ();
1073
1074 return; 1208 return;
1075 } 1209 }
1076 else if (ip [3] == CMD_IP_SYN) 1210 else if (ip [3] == CMD_IP_SYN)
1077 { 1211 {
1078 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1212 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1079 dns->established = true; 1213 dns->established = true;
1080 } 1214 }
1215 else if (ip [3] == CMD_IP_CSE)
1216 {
1217 if (conf.dns_case_preserving)
1218 {
1219 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1220 conf.dns_case_preserving = false;
1221 dns->reset ();
1222 return;
1223 }
1224 else
1225 {
1226 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1227 dns->established = true;
1228 }
1229 }
1081 else if (ip [3] == CMD_IP_REJ) 1230 else if (ip [3] == CMD_IP_REJ)
1082 { 1231 {
1083 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1232 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1084 abort (); 1233 dns->tw.start (60.);
1085 } 1234 }
1086 else 1235 else
1236 {
1087 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1237 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1238 dns->tw.start (60.);
1239 }
1088 } 1240 }
1089 else 1241 else
1090 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1242 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1091 ip [0], ip [1], ip [2], ip [3]); 1243 ip [0], ip [1], ip [2], ip [3]);
1092 1244
… …
1116 break; 1268 break;
1117 } 1269 }
1118} 1270}
1119 1271
1120void 1272void
1121vpn::dnsv4_ev (io_watcher &w, short revents) 1273vpn::dnsv4_ev (ev::io &w, int revents)
1122{ 1274{
1123 if (revents & EVENT_READ) 1275 if (revents & EV_READ)
1124 { 1276 {
1125 dns_packet *pkt = new dns_packet; 1277 dns_packet *pkt = new dns_packet;
1126 struct sockaddr_in sa; 1278 struct sockaddr_in sa;
1127 socklen_t sa_len = sizeof (sa); 1279 socklen_t sa_len = sizeof (sa);
1128 1280
1129 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1281 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1130 1282
1131 if (pkt->len > 0) 1283 if (pkt->len > 0)
1132 { 1284 {
1133 if (THISNODE->dns_port) 1285 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1286 dnsv4_client (*pkt);
1287 else
1134 { 1288 {
1135 dnsv4_server (*pkt); 1289 dnsv4_server (*pkt);
1136 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1290 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1137 } 1291 }
1138 else
1139 dnsv4_client (*pkt);
1140 1292
1141 delete pkt; 1293 delete pkt;
1142 } 1294 }
1143 } 1295 }
1144} 1296}
1145 1297
1146bool 1298bool
1147connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1299vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1148{ 1300{
1301 int client = ntohl (si.host);
1302
1303 assert (0 < client && client <= conns.size ());
1304
1305 connection *c = conns [client - 1];
1306
1149 if (!dns) 1307 if (!c->dns)
1150 dns = new dns_connection (this); 1308 c->dns = new dns_connection (c);
1151 1309
1152 if (!dns->snddq.put (pkt)) 1310 if (c->dns->snddq.put (pkt))
1153 return false; 1311 {
1312 min_it (c->dns->poll_interval, 0.25);
1313 c->dns->tw ();
1314 }
1154 1315
1155 dns->tw.trigger (); 1316 // always return true even if the buffer overflows
1156
1157 return true; 1317 return true;
1158} 1318}
1159 1319
1160void 1320void
1161connection::dnsv4_reset_connection () 1321dns_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{ 1322{
1171 // servers have to be polled 1323 // servers have to be polled
1172 if (THISNODE->dns_port) 1324 if (THISNODE->dns_port)
1173 return; 1325 return;
1174 1326
1175 // check for timeouts and (re)transmit 1327 // check for timeouts and (re)transmit
1176 tstamp next = NOW + poll_interval; 1328 tstamp next = 86400 * 365;
1177 dns_snd *send = 0; 1329 dns_snd *send = 0;
1178 1330
1179 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1331 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1180 i != vpn->dns_sndpq.end (); 1332 i != vpn->dns_sndpq.end ();
1181 ++i) 1333 ++i)
1182 { 1334 {
1183 dns_snd *r = *i; 1335 dns_snd *r = *i;
1184 1336
1185 if (r->timeout <= NOW) 1337 if (r->timeout <= ev_now ())
1186 { 1338 {
1187 if (!send) 1339 if (!send)
1188 { 1340 {
1189 send = r; 1341 send = r;
1190 1342
1191 r->retry++; 1343 r->retry++;
1192 r->timeout = NOW + (r->retry * last_latency * 8.); 1344 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1345 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1193 1346
1194 // the following code changes the query section a bit, forcing 1347 // the following code changes the query section a bit, forcing
1195 // the forwarder to generate a new request 1348 // the forwarder to generate a new request
1196 if (r->stdhdr) 1349 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); 1350 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1200 }
1201 } 1351 }
1202 } 1352 }
1203 else 1353 else
1204 NEXT (r->timeout); 1354 min_it (next, r->timeout - ev_now ());
1205 }
1206
1207 if (last_sent + send_interval <= NOW)
1208 { 1355 }
1356
1209 if (!send) 1357 if (!send)
1358 {
1359 // generate a new packet, if wise
1360
1361 if (!established)
1210 { 1362 {
1211 // generate a new packet, if wise 1363 if (vpn->dns_sndpq.empty ())
1212
1213 if (!established)
1214 { 1364 {
1215 if (vpn->dns_sndpq.empty ())
1216 {
1217 send = new dns_snd (this); 1365 send = new dns_snd (this);
1218 1366
1219 cfg.reset (THISNODE->id); 1367 cfg.reset (THISNODE->id);
1368 set_cfg ();
1220 send->gen_syn_req (cfg); 1369 send->gen_syn_req ();
1221 }
1222 } 1370 }
1223 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1371 }
1372 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1224 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1373 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1374 {
1375 if (last_sent + send_interval <= ev_now ())
1225 { 1376 {
1377 //printf ("sending data request etc.\n"); //D
1226 if (!snddq.empty ()) 1378 if (!snddq.empty ())
1227 {
1228 poll_interval = send_interval;
1229 NEXT (NOW + send_interval); 1379 min_it (next, send_interval);
1230 }
1231 1380
1232 send = new dns_snd (this); 1381 send = new dns_snd (this);
1233 send->gen_stream_req (sndseq, snddq); 1382 send->gen_stream_req (sndseq, snddq);
1234 send->timeout = NOW + last_latency * 8.; 1383 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1384 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1235 1385
1236 sndseq = (sndseq + 1) & SEQNO_MASK; 1386 sndseq = (sndseq + 1) & SEQNO_MASK;
1237 } 1387 }
1238 1388 else
1239 if (send) 1389 min_it (next, last_sent + send_interval - ev_now ());
1240 vpn->dns_sndpq.push_back (send);
1241 } 1390 }
1242 1391
1243 if (send) 1392 if (send)
1244 { 1393 vpn->dns_sndpq.push_back (send);
1245 last_sent = NOW; 1394 }
1395
1396 if (send)
1397 {
1398 last_sent = ev_now ();
1246 sendto (vpn->dnsv4_fd, 1399 sendto (vpn->dnsv4_fd,
1247 send->pkt->at (0), send->pkt->len, 0, 1400 send->pkt->at (0), send->pkt->len, 0,
1248 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1401 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1249 }
1250 } 1402 }
1251 else
1252 NEXT (last_sent + send_interval);
1253 1403
1404 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1405
1254 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1406 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1255 poll_interval, send_interval, next - NOW, 1407 poll_interval, send_interval, next - ev_now (),
1256 vpn->dns_sndpq.size (), snddq.size ()); 1408 vpn->dns_sndpq.size (), snddq.size (),
1257 1409 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 1410
1262 w.start (next); 1411 w.start (next);
1263} 1412}
1264 1413
1265#endif 1414#endif

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