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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.18 by pcg, Sat Mar 5 19:13:16 2005 UTC vs.
Revision 1.53 by root, Tue Oct 18 10:54:17 2011 UTC

1/* 1/*
2 vpn_dns.C -- handle the dns tunnel part of the protocol. 2 vpn_dns.C -- handle the dns tunnel part of the protocol.
3 Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de> 3 Copyright (C) 2003-2011 Marc Lehmann <gvpe@schmorp.de>
4 4
5 This file is part of GVPE. 5 This file is part of GVPE.
6 6
7 GVPE is free software; you can redistribute it and/or modify 7 GVPE is free software; you can redistribute it and/or modify it
8 it under the terms of the GNU General Public License as published by 8 under the terms of the GNU General Public License as published by the
9 the Free Software Foundation; either version 2 of the License, or 9 Free Software Foundation; either version 3 of the License, or (at your
10 (at your option) any later version. 10 option) any later version.
11 11
12 This program is distributed in the hope that it will be useful, 12 This program is distributed in the hope that it will be useful, but
13 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15 GNU General Public License for more details. 15 Public License for more details.
16 16
17 You should have received a copy of the GNU General Public License 17 You should have received a copy of the GNU General Public License along
18 along with gvpe; if not, write to the Free Software 18 with this program; if not, see <http://www.gnu.org/licenses/>.
19 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19
20 Additional permission under GNU GPL version 3 section 7
21
22 If you modify this Program, or any covered work, by linking or
23 combining it with the OpenSSL project's OpenSSL library (or a modified
24 version of that library), containing parts covered by the terms of the
25 OpenSSL or SSLeay licenses, the licensors of this Program grant you
26 additional permission to convey the resulting work. Corresponding
27 Source for a non-source form of such a combination shall include the
28 source code for the parts of OpenSSL used as well as that of the
29 covered work.
20*/ 30*/
31
32// TODO: EDNS0 option to increase dns mtu?
33// TODO: re-write dns packet parsing/creation using a safe mem-buffer
34// to ensure no buffer overflows or similar problems.
21 35
22#include "config.h" 36#include "config.h"
23 37
24#if ENABLE_DNS 38#if ENABLE_DNS
25 39
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 40// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27// it's a hack, use only in emergency situations please. 41// it's a hack, use only in emergency situations please.
28 42
29#include <cstring> 43#include <cstring>
44#include <cassert>
30 45
31#include <sys/types.h> 46#include <sys/types.h>
32#include <sys/socket.h> 47#include <sys/socket.h>
33#include <sys/wait.h> 48#include <sys/wait.h>
34#include <sys/uio.h> 49#include <sys/uio.h>
… …
37#include <unistd.h> 52#include <unistd.h>
38#include <fcntl.h> 53#include <fcntl.h>
39 54
40#include <map> 55#include <map>
41 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
42#include <gmp.h> 58#include <gmp.h>
43 59
44#include "netcompat.h" 60#include "netcompat.h"
45 61
46#include "vpn.h" 62#include "vpn.h"
47 63
48#define MIN_POLL_INTERVAL .02 // how often to poll minimally when the server has data 64#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received
49#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data 65#define MAX_POLL_INTERVAL 1. // how often to poll minimally when the server has no data
50#define ACTIVITY_INTERVAL 5.
51 66
52#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
53#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54 69
55#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
56#define MAX_SEND_INTERVAL 0.5 // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
57 71
58#define MAX_OUTSTANDING 10 // max. outstanding requests
59#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
60#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE 73#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
61 74
62#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well 75#define MAX_DOMAIN_SIZE 235 // 255 is legal limit, but bind doesn't compress well
63// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
64// every two request bytes less give room for one reply byte 77// every request byte less give room for two reply bytes
65 78
66#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
67#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
68 81
69#define MAX_LBL_SIZE 63 82#define MAX_LBL_SIZE 63
70#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
71 84
72#define RR_TYPE_A 1 85#define RR_TYPE_A 1
73#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
74#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
75#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
76 90
77#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
78 92
79#define CMD_IP_1 207 93#define CMD_IP_1 207
80#define CMD_IP_2 46 94#define CMD_IP_2 46
81#define CMD_IP_3 236 95#define CMD_IP_3 236
82#define CMD_IP_RST 29 96
83#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
84#define CMD_IP_REJ 32 98#define CMD_IP_REJ 32 // do not want you
99#define CMD_IP_SYN 113 // connection established
100#define CMD_IP_CSE 213 // connection established, but likely case mismatch
101
102static bool
103is_uc (char c)
104{
105 return 'A' <= c && c <= 'Z';
106}
107
108static bool
109is_lc (char c)
110{
111 return 'a' <= c && c <= 'z';
112}
85 113
86// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
87struct charmap 115struct charmap
88{ 116{
89 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
103 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
104 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
105 133
106 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
107 { 135 {
136 char c = cmap [size];
137
108 enc [size] = cmap [size]; 138 enc [size] = c;
109 dec [(u8)enc [size]] = size; 139 dec [(u8)c] = size;
140
141 // allow lowercase/uppercase aliases if possible
142 if (is_uc (c) && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size;
143 if (is_lc (c) && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size;
110 } 144 }
111 145
112 assert (size < 256); 146 assert (size < 256);
113} 147}
114 148
… …
121{ 155{
122 charmap cmap; 156 charmap cmap;
123 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
124 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
125 159
126 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
127 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
128 162
129 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
130 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
131 165
132 basecoder (const char *cmap); 166 basecoder (const char *cmap);
133}; 167};
134 168
135basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
154 enc_len [len] = n; 188 enc_len [len] = n;
155 dec_len [n] = len; 189 dec_len [n] = len;
156 } 190 }
157} 191}
158 192
193unsigned int
159unsigned int basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
160{ 195{
161 return enc_len [len]; 196 return enc_len [len];
162} 197}
163 198
199unsigned int
164unsigned int basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
165{ 201{
166 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
167 --len; 203 --len;
168 204
169 return dec_len [len]; 205 return dec_len [len];
170} 206}
171 207
208unsigned int
172unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
173{ 210{
174 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
175 return 0; 212 return 0;
176 213
177 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
196 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
197 234
198 return elen; 235 return elen;
199} 236}
200 237
238unsigned int
201unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
202{ 240{
203 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
204 return 0; 242 return 0;
205 243
206 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
255 } 293 }
256 abort (); 294 abort ();
257} 295}
258#endif 296#endif
259 297
260//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
261//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
262static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
263//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
264static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
265 301
266///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
267 303
268#define HDRSIZE 6 304#define HDRSIZE 5
269 305
306inline void
270inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
271{ 308{
309 assert (clientid < 256);
310
272 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
273 312
274 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
275 clientid, 316 clientid,
276 (seqno >> 8) | (retry << 6),
277 seqno,
278 }; 317 };
279 318
280 assert (clientid < 256);
281
282 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
283} 320}
284 321
322inline void
285inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
286{ 324{
287 u8 hdr[3]; 325 u8 hdr[3];
288 326
289 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
290 328
291 clientid = hdr[0]; 329 clientid = hdr[2];
292 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
293} 331}
294 332
295///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
296 334
297struct byte_stream 335struct byte_stream
… …
323byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
324{ 362{
325 delete data; 363 delete data;
326} 364}
327 365
366void
328void byte_stream::remove (int count) 367byte_stream::remove (int count)
329{ 368{
330 if (count > fill) 369 if (count > fill)
331 assert (count <= fill); 370 assert (count <= fill);
332 371
333 memmove (data, data + count, fill -= count); 372 memmove (data, data + count, fill -= count);
334} 373}
335 374
375bool
336bool byte_stream::put (u8 *data, unsigned int datalen) 376byte_stream::put (u8 *data, unsigned int datalen)
337{ 377{
338 if (maxsize - fill < datalen) 378 if (maxsize - fill < datalen)
339 return false; 379 return false;
340 380
341 memcpy (this->data + fill, data, datalen); fill += datalen; 381 memcpy (this->data + fill, data, datalen); fill += datalen;
342 382
343 return true; 383 return true;
344} 384}
345 385
386bool
346bool byte_stream::put (vpn_packet *pkt) 387byte_stream::put (vpn_packet *pkt)
347{ 388{
348 if (maxsize - fill < pkt->len + 2) 389 if (maxsize - fill < pkt->len + 2)
349 return false; 390 return false;
350 391
351 data [fill++] = pkt->len >> 8; 392 data [fill++] = pkt->len >> 8;
… …
407 448
408struct dns_cfg 449struct dns_cfg
409{ 450{
410 static int next_uid; 451 static int next_uid;
411 452
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
412 u8 id1, id2, id3, id4; 461 u8 id1, id2, id3, id4;
413 u8 version; 462
414 u8 rrtype; 463 u16 client;
415 u8 flags;
416 u8 def_ttl; 464 u8 def_ttl;
417 u8 rcv_cdc; 465 u8 r0;
418 u8 snd_cdc;
419 u16 max_size;
420 u16 client;
421 u16 uid; // to make request unique
422 466
423 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;
424 473
425 void reset (int clientid); 474 void reset (int clientid);
426 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
427}; 477};
428 478
429int dns_cfg::next_uid; 479int dns_cfg::next_uid;
430 480
481void
431void dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
432{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
433 id1 = 'G'; 485 id1 = 'G';
434 id2 = 'V'; 486 id2 = 'V';
435 id3 = 'P'; 487 id3 = 'P';
436 id4 = 'E'; 488 id4 = 'E';
437 489
438 version = 1; 490 version = 2;
439 491
440 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
441 flags = 0; 493 flags = 0;
442 def_ttl = 1; 494 def_ttl = 0;
443 rcv_cdc = 0;
444 snd_cdc = 62; 495 syn_cdc = 26;
496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
498 rep_cdc = 0;
445 max_size = ntohs (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
446 client = ntohs (clientid); 500 client = htons (clientid);
447 uid = next_uid++; 501 uid = ++next_uid;
448 502
449 memset (reserved, 0, 8); 503 r0 = r1 = r2 = r3 = r4 = 0;
450}
451 504
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
452bool dns_cfg::valid () 526dns_cfg::valid ()
453{ 527{
528 // although the protocol itself allows for some configurability,
529 // only the following encoding/decoding settings are implemented.
454 return id1 == 'G' 530 return id1 == 'G'
455 && id2 == 'V' 531 && id2 == 'V'
456 && id3 == 'P' 532 && id3 == 'P'
457 && id4 == 'E' 533 && id4 == 'E'
458 && version == 1 534 && version == 2
459 && flags == 0
460 && rcv_cdc == 0
461 && snd_cdc == 62 535 && syn_cdc == 26
462 && 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 ();
463} 540}
464 541
465struct dns_packet : net_packet 542struct dns_packet : net_packet
466{ 543{
467 u16 id; 544 u16 id;
468 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
469 u16 qdcount, ancount, nscount, arcount; 546 u16 qdcount, ancount, nscount, arcount;
470 547
471 u8 data[MAXSIZE - 6 * 2]; 548 u8 data [MAXSIZE - 6 * 2];
472 549
473 int decode_label (char *data, int size, int &offs); 550 int decode_label (char *data, int size, int &offs);
474}; 551};
475 552
553int
476int dns_packet::decode_label (char *data, int size, int &offs) 554dns_packet::decode_label (char *data, int size, int &offs)
477{ 555{
478 char *orig = data; 556 char *orig = data;
479 557
480 memset (data, 0, size); 558 memset (data, 0, size);
481 559
… …
507 return data - orig; 585 return data - orig;
508} 586}
509 587
510///////////////////////////////////////////////////////////////////////////// 588/////////////////////////////////////////////////////////////////////////////
511 589
590static
591u16 next_id ()
592{
512static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
513 594
514static u16 next_id () 595#if 1
515{
516 if (!dns_id) 596 if (!dns_id)
517 dns_id = time (0); 597 dns_id = time (0);
518 598
519 // the simplest lsfr with periodicity 65535 i could find 599 // the simplest lsfr with periodicity 65535 i could find
520 dns_id = (dns_id << 1) 600 dns_id = (dns_id << 1)
… …
522 ^ (dns_id >> 2) 602 ^ (dns_id >> 2)
523 ^ (dns_id >> 4) 603 ^ (dns_id >> 4)
524 ^ (dns_id >> 15)) & 1); 604 ^ (dns_id >> 15)) & 1);
525 605
526 return dns_id; 606 return dns_id;
607#else
608 dns_id++;//D
609
610 return htons (dns_id);
611#endif
527} 612}
528 613
529struct dns_rcv; 614struct dns_rcv;
530struct dns_snd; 615struct dns_snd;
531 616
… …
535 struct vpn *vpn; 620 struct vpn *vpn;
536 621
537 dns_cfg cfg; 622 dns_cfg cfg;
538 623
539 bool established; 624 bool established;
625 const basecoder *cdc;
540 626
541 tstamp last_received; 627 tstamp last_received;
542 tstamp last_sent; 628 tstamp last_sent;
543 double last_latency; 629 double min_latency;
544 double poll_interval, send_interval; 630 double poll_interval, send_interval;
545 631
546 vector<dns_rcv *> rcvpq; 632 vector<dns_rcv *> rcvpq;
547 633
548 byte_stream rcvdq; int rcvseq; 634 byte_stream rcvdq; int rcvseq; int repseq;
549 byte_stream snddq; int sndseq; 635 byte_stream snddq; int sndseq;
550 636
551 void time_cb (time_watcher &w); time_watcher tw; 637 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
552 void receive_rep (dns_rcv *r); 638 void receive_rep (dns_rcv *r);
639
640 void reset (); // quite like tcp RST
641 void set_cfg (); // to be called after any cfg changes
553 642
554 dns_connection (connection *c); 643 dns_connection (connection *c);
555 ~dns_connection (); 644 ~dns_connection ();
556}; 645};
557 646
… …
575: dns (dns) 664: dns (dns)
576{ 665{
577 timeout = 0; 666 timeout = 0;
578 retry = 0; 667 retry = 0;
579 seqno = 0; 668 seqno = 0;
580 sent = NOW; 669 sent = ev_now ();
581 stdhdr = false; 670 stdhdr = false;
582 671
583 pkt = new dns_packet; 672 pkt = new dns_packet;
584 673
585 pkt->id = next_id (); 674 pkt->id = next_id ();
… …
588dns_snd::~dns_snd () 677dns_snd::~dns_snd ()
589{ 678{
590 delete pkt; 679 delete pkt;
591} 680}
592 681
682static void
593static void append_domain (dns_packet &pkt, int &offs, const char *domain) 683append_domain (dns_packet &pkt, int &offs, const char *domain)
594{ 684{
595 // add tunnel domain 685 // add tunnel domain
596 for (;;) 686 for (;;)
597 { 687 {
598 const char *end = strchr (domain, '.'); 688 const char *end = strchr (domain, '.');
… …
611 701
612 domain = end + 1; 702 domain = end + 1;
613 } 703 }
614} 704}
615 705
706void
616void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 707dns_snd::gen_stream_req (int seqno, byte_stream &stream)
617{ 708{
618 stdhdr = true; 709 stdhdr = true;
619 this->seqno = seqno; 710 this->seqno = seqno;
620 711
621 timeout = NOW + INITIAL_TIMEOUT; 712 timeout = ev_now () + INITIAL_TIMEOUT;
622 713
623 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 714 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
624 pkt->qdcount = htons (1); 715 pkt->qdcount = htons (1);
625 716
626 int offs = 6*2; 717 int offs = 6*2;
627 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 718 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
628 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 719 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
629 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 720 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
630 721
631 char enc[256], *encp = enc; 722 char enc[256], *encp = enc;
632 encode_header (enc, THISNODE->id, seqno); 723 encode_header (enc, THISNODE->id, seqno);
633 724
634 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 725 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
635 726
636 if (datalen > stream.size ()) 727 if (datalen > stream.size ())
637 datalen = stream.size (); 728 datalen = stream.size ();
638 729
639 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 730 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
640 stream.remove (datalen); 731 stream.remove (datalen);
641 732
642 while (enclen) 733 while (enclen)
643 { 734 {
644 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 735 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
650 encp += lbllen; 741 encp += lbllen;
651 742
652 enclen -= lbllen; 743 enclen -= lbllen;
653 } 744 }
654 745
655 append_domain (*pkt, offs, THISNODE->domain); 746 append_domain (*pkt, offs, dns->c->conf->domain);
656 747
657 (*pkt)[offs++] = 0; 748 (*pkt)[offs++] = 0;
658 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 749 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
659 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 750 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
660 751
661 pkt->len = offs; 752 pkt->len = offs;
662} 753}
663 754
755void
664void dns_snd::gen_syn_req () 756dns_snd::gen_syn_req ()
665{ 757{
666 timeout = NOW + INITIAL_SYN_TIMEOUT; 758 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
667
668 printf ("send syn\n");//D
669 759
670 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 760 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
671 pkt->qdcount = htons (1); 761 pkt->qdcount = htons (1);
672 762
673 int offs = 6 * 2; 763 int offs = 6 * 2;
… …
676 766
677 assert (elen <= MAX_LBL_SIZE); 767 assert (elen <= MAX_LBL_SIZE);
678 768
679 (*pkt)[offs] = elen; 769 (*pkt)[offs] = elen;
680 offs += elen + 1; 770 offs += elen + 1;
681 append_domain (*pkt, offs, THISNODE->domain); 771 append_domain (*pkt, offs, dns->c->conf->domain);
682 772
683 (*pkt)[offs++] = 0; 773 (*pkt)[offs++] = 0;
684 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 774 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
685 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 775 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
686 776
… …
712///////////////////////////////////////////////////////////////////////////// 802/////////////////////////////////////////////////////////////////////////////
713 803
714dns_connection::dns_connection (connection *c) 804dns_connection::dns_connection (connection *c)
715: c (c) 805: c (c)
716, rcvdq (MAX_BACKLOG * 2) 806, rcvdq (MAX_BACKLOG * 2)
717, snddq (MAX_BACKLOG * 2) 807, snddq (MAX_BACKLOG)
718, tw (this, &dns_connection::time_cb)
719{ 808{
809 tw.set<dns_connection, &dns_connection::time_cb> (this);
810
720 vpn = c->vpn; 811 vpn = c->vpn;
721 812
813 reset ();
814}
815
816dns_connection::~dns_connection ()
817{
818 reset ();
819}
820
821void
822dns_connection::reset ()
823{
824 while (!rcvpq.empty ())
825 {
826 delete rcvpq.back ();
827 rcvpq.pop_back ();
828 }
829
830 for (int i = vpn->dns_sndpq.size (); i--; )
831 if (vpn->dns_sndpq [i]->dns == this)
832 {
833 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
834 vpn->dns_sndpq.pop_back ();
835 }
836
722 established = false; 837 established = false;
723 838
724 rcvseq = sndseq = 0; 839 rcvseq = repseq = sndseq = 0;
725 840
726 last_sent = last_received = 0; 841 last_sent = 0;
727 poll_interval = MIN_POLL_INTERVAL; 842 poll_interval = 0.5; // starting here
728 send_interval = 0.5; // starting rate 843 send_interval = 0.5; // starting rate
729 last_latency = INITIAL_TIMEOUT; 844 min_latency = INITIAL_TIMEOUT;
730} 845}
731 846
732dns_connection::~dns_connection () 847void
848dns_connection::set_cfg ()
733{ 849{
734 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 850 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
735 i != rcvpq.end ();
736 ++i)
737 delete *i;
738} 851}
739 852
853void
740void dns_connection::receive_rep (dns_rcv *r) 854dns_connection::receive_rep (dns_rcv *r)
741{ 855{
742 if (r->datalen) 856 if (r->datalen)
743 { 857 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
744 last_received = NOW;
745 tw.trigger ();
746
747 poll_interval = send_interval;
748 }
749 else 858 else
750 { 859 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
751 poll_interval *= 1.5;
752 if (poll_interval > MAX_POLL_INTERVAL)
753 poll_interval = MAX_POLL_INTERVAL;
754 }
755 860
756 rcvpq.push_back (r); 861 rcvpq.push_back (r);
757 862
758 redo: 863 redo:
759 864
760 // find next packet 865 // find next packet
761 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 866 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
762 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 867 if (SEQNO_EQ (rcvseq, (*i)->seqno))
763 { 868 {
869 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
764 // enter the packet into our input stream 870 // enter the packet into our input stream
765 r = *i; 871 r = *i;
766 872
767 // remove the oldest packet, look forward, as it's oldest first 873 // remove the oldest packet, look forward, as it's oldest first
768 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 874 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
769 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 875 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
770 { 876 {
877 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
771 delete *j; 878 delete *j;
772 rcvpq.erase (j); 879 rcvpq.erase (j);
773 break; 880 break;
774 } 881 }
775 882
776 rcvseq = (rcvseq + 1) & SEQNO_MASK; 883 rcvseq = (rcvseq + 1) & SEQNO_MASK;
777 884
778 if (!rcvdq.put (r->data, r->datalen)) 885 if (!rcvdq.put (r->data, r->datalen))
779 { 886 {
887 // MUST never overflow, can be caused by data corruption, TODO
780 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 888 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
781 abort (); // MUST never overflow, can be caused by data corruption, TODO 889 reset ();
890 return;
782 } 891 }
783 892
784 while (vpn_packet *pkt = rcvdq.get ()) 893 while (vpn_packet *pkt = rcvdq.get ())
785 { 894 {
786 sockinfo si; 895 sockinfo si;
787 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 896 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
788 897
789 vpn->recv_vpn_packet (pkt, si); 898 vpn->recv_vpn_packet (pkt, si);
790
791 delete pkt; 899 delete pkt;
792 } 900 }
793 901
794 // check for further packets 902 // check for further packets
795 goto redo; 903 goto redo;
… …
806 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 914 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
807 915
808 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 916 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
809 && pkt.qdcount == htons (1)) 917 && pkt.qdcount == htons (1))
810 { 918 {
811 char qname[MAXSIZE]; 919 char qname [MAXSIZE];
812 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 920 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
813 921
814 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 922 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
815 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 923 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
816 924
… …
823 931
824 int dlen = strlen (THISNODE->domain); 932 int dlen = strlen (THISNODE->domain);
825 933
826 if (qclass == RR_CLASS_IN 934 if (qclass == RR_CLASS_IN
827 && qlen > dlen + 1 935 && qlen > dlen + 1
828 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 936 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
829 { 937 {
830 // now generate reply 938 // now generate reply
831 pkt.ancount = htons (1); // one answer RR 939 pkt.ancount = htons (1); // one answer RR
832 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 940 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
833 941
… …
838 { 946 {
839 // correct class, domain: parse 947 // correct class, domain: parse
840 int client, seqno; 948 int client, seqno;
841 decode_header (qname, client, seqno); 949 decode_header (qname, client, seqno);
842 950
843 u8 data[MAXSIZE];
844 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
845
846 if (0 < client && client <= conns.size ()) 951 if (0 < client && client <= conns.size ())
847 { 952 {
848 connection *c = conns [client - 1]; 953 connection *c = conns [client - 1];
849 dns_connection *dns = c->dns; 954 dns_connection *dns = c->dns;
850 dns_rcv *rcv; 955 dns_rcv *rcv;
851 bool in_seq;
852 956
853 if (dns) 957 if (dns)
854 { 958 {
959 u8 data[MAXSIZE];
960 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
961
855 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 962 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
856 if (SEQNO_EQ ((*i)->seqno, seqno)) 963 if (SEQNO_EQ ((*i)->seqno, seqno))
857 { 964 {
858 // already seen that request: simply reply with the cached reply 965 // already seen that request: simply reply with the cached reply
859 dns_rcv *r = *i; 966 dns_rcv *r = *i;
… …
867 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 974 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
868 975
869 goto duplicate_request; 976 goto duplicate_request;
870 } 977 }
871 978
872 in_seq = dns->rcvseq == seqno;
873
874 // new packet, queue 979 // new packet, queue
875 rcv = new dns_rcv (seqno, data, datalen); 980 rcv = new dns_rcv (seqno, data, datalen);
876 dns->receive_rep (rcv); 981 dns->receive_rep (rcv);
877 } 982 }
878 983
984 {
879 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 985 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
880 986
881 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 987 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
882 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 988 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
883 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 989 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
884 pkt [offs++] = 0; pkt [offs++] = 0; 990 pkt [offs++] = 0; pkt [offs++] = 0;
885 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 991 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
886 992
887 int rdlen_offs = offs += 2; 993 int rdlen_offs = offs += 2;
888 994
995 if (dns)
996 {
889 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 997 int dlen = ntohs (dns->cfg.max_size) - offs;
998
890 // bind doesn't compress well, so reduce further by one label length 999 // bind doesn't compress well, so reduce further by one label length
891 dlen -= qlen; 1000 dlen -= qlen;
892 1001
893 if (dns)
894 {
895 // only put data into in-order sequence packets, if 1002 // only put data into in-order sequence packets, if
896 // we receive out-of-order packets we generate empty 1003 // we receive out-of-order packets we generate empty
897 // replies 1004 // replies
898 while (dlen > 1 && !dns->snddq.empty () && in_seq) 1005 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
1006 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
899 { 1007 {
1008 dns->repseq = seqno;
1009
1010 while (dlen > 1 && !dns->snddq.empty ())
1011 {
900 int txtlen = dlen <= 255 ? dlen - 1 : 255; 1012 int txtlen = dlen <= 255 ? dlen - 1 : 255;
901 1013
902 if (txtlen > dns->snddq.size ()) 1014 if (txtlen > dns->snddq.size ())
903 txtlen = dns->snddq.size (); 1015 txtlen = dns->snddq.size ();
904 1016
905 pkt[offs++] = txtlen; 1017 pkt[offs++] = txtlen;
906 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 1018 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
907 offs += txtlen; 1019 offs += txtlen;
908 dns->snddq.remove (txtlen); 1020 dns->snddq.remove (txtlen);
909 1021
910 dlen -= txtlen + 1; 1022 dlen -= txtlen + 1;
1023 }
911 } 1024 }
912 1025
913 // avoid empty TXT rdata 1026 // avoid completely empty TXT rdata
914 if (offs == rdlen_offs) 1027 if (offs == rdlen_offs)
915 pkt[offs++] = 0; 1028 pkt[offs++] = 0;
916 1029
917 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 1030 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
918 } 1031 }
919 else 1032 else
920 { 1033 {
921 // send RST 1034 // send RST
922 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1035 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
923 pkt [offs++] = CMD_IP_RST; 1036 pkt [offs++] = CMD_IP_RST;
924 } 1037 }
925 1038
926 int rdlen = offs - rdlen_offs; 1039 int rdlen = offs - rdlen_offs;
927 1040
928 pkt [rdlen_offs - 2] = rdlen >> 8; 1041 pkt [rdlen_offs - 2] = rdlen >> 8;
929 pkt [rdlen_offs - 1] = rdlen; 1042 pkt [rdlen_offs - 1] = rdlen;
930 1043
931 if (dns) 1044 if (dns)
932 { 1045 {
933 // now update dns_rcv copy 1046 // now update dns_rcv copy
934 rcv->pkt->len = offs; 1047 rcv->pkt->len = offs;
935 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 1048 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
936 } 1049 }
1050 }
937 1051
938 duplicate_request: ; 1052 duplicate_request: ;
939 } 1053 }
940 else 1054 else
941 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 1055 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
953 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1067 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
954 pkt [offs++] = 0; pkt [offs++] = 0; 1068 pkt [offs++] = 0; pkt [offs++] = 0;
955 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1069 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
956 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1070 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
957 1071
958 slog (L_INFO, _("DNS: client %d tries to connect"), client);
959
960 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1072 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
961 pkt [offs++] = CMD_IP_REJ; 1073 pkt [offs++] = CMD_IP_REJ;
962 1074
963 if (0 < client && client <= conns.size ()) 1075 if (0 < client && client <= conns.size ())
964 { 1076 {
965 connection *c = conns [client - 1]; 1077 connection *c = conns [client - 1];
966 1078
967 if (cfg.valid ()) 1079 if (cfg.valid ())
968 { 1080 {
969 pkt [offs - 1] = CMD_IP_SYN; 1081 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1082
1083 // check for any encoding mismatches - hints at a case problem
1084 char qname2 [MAX_ENC_LEN];
1085 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
970 1086
971 delete c->dns; 1087 delete c->dns;
1088
1089 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1090 ? CMD_IP_CSE : CMD_IP_SYN;
1091
972 c->dns = new dns_connection (c); 1092 c->dns = new dns_connection (c);
973 c->dns->cfg = cfg; 1093 c->dns->cfg = cfg;
1094 c->dns->set_cfg ();
974 } 1095 }
975 } 1096 }
976 } 1097 }
977 } 1098 }
978 1099
… …
997 { 1118 {
998 dns_connection *dns = (*i)->dns; 1119 dns_connection *dns = (*i)->dns;
999 connection *c = dns->c; 1120 connection *c = dns->c;
1000 int seqno = (*i)->seqno; 1121 int seqno = (*i)->seqno;
1001 u8 data[MAXSIZE], *datap = data; 1122 u8 data[MAXSIZE], *datap = data;
1123 //printf ("rcv pkt %x\n", seqno);//D
1002 1124
1003 if ((*i)->retry) 1125 if ((*i)->retry)
1004 { 1126 {
1005 dns->send_interval *= 1.01; 1127 dns->send_interval *= 1.01;
1006 if (dns->send_interval > MAX_SEND_INTERVAL) 1128 if (dns->send_interval > MAX_SEND_INTERVAL)
1007 dns->send_interval = MAX_SEND_INTERVAL; 1129 dns->send_interval = MAX_SEND_INTERVAL;
1008 } 1130 }
1009 else 1131 else
1010 { 1132 {
1011#if 1 1133#if 0
1012 dns->send_interval *= 0.999; 1134 dns->send_interval *= 0.999;
1013#endif 1135#endif
1014 if (dns->send_interval < MIN_SEND_INTERVAL)
1015 dns->send_interval = MIN_SEND_INTERVAL;
1016
1017 // the latency surely puts an upper bound on 1136 // the latency surely puts an upper bound on
1018 // the minimum send interval 1137 // the minimum send interval
1019 double latency = NOW - (*i)->sent; 1138 double latency = ev_now () - (*i)->sent;
1139
1140 if (latency < dns->min_latency)
1020 dns->last_latency = latency; 1141 dns->min_latency = latency;
1021 1142
1022 if (dns->send_interval > latency) 1143 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1144 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1145
1146 if (dns->send_interval < conf.dns_send_interval)
1023 dns->send_interval = latency; 1147 dns->send_interval = conf.dns_send_interval;
1024 } 1148 }
1025 1149
1026 delete *i; 1150 delete *i;
1027 dns_sndpq.erase (i); 1151 dns_sndpq.erase (i);
1028 1152
… …
1046 ttl |= pkt [offs++] << 16; 1170 ttl |= pkt [offs++] << 16;
1047 ttl |= pkt [offs++] << 8; 1171 ttl |= pkt [offs++] << 8;
1048 ttl |= pkt [offs++]; 1172 ttl |= pkt [offs++];
1049 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1173 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1050 1174
1051 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1175 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1052 { 1176 {
1053 if (rdlen <= MAXSIZE - offs) 1177 if (rdlen <= MAXSIZE - offs)
1054 { 1178 {
1055 // decode bytes, finally 1179 // decode bytes, finally
1056 1180
… …
1082 { 1206 {
1083 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1207 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1084 1208
1085 if (ip [3] == CMD_IP_RST) 1209 if (ip [3] == CMD_IP_RST)
1086 { 1210 {
1087 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1211 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1088 1212
1089 delete dns; c->dns = 0; 1213 dns->reset ();
1090
1091 return; 1214 return;
1092 } 1215 }
1093 else if (ip [3] == CMD_IP_SYN) 1216 else if (ip [3] == CMD_IP_SYN)
1094 { 1217 {
1095 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1218 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1096 dns->established = true; 1219 dns->established = true;
1097 } 1220 }
1221 else if (ip [3] == CMD_IP_CSE)
1222 {
1223 if (conf.dns_case_preserving)
1224 {
1225 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1226 conf.dns_case_preserving = false;
1227 dns->reset ();
1228 return;
1229 }
1230 else
1231 {
1232 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1233 dns->established = true;
1234 }
1235 }
1098 else if (ip [3] == CMD_IP_REJ) 1236 else if (ip [3] == CMD_IP_REJ)
1099 { 1237 {
1100 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1238 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1101 abort (); 1239 dns->tw.start (60.);
1102 } 1240 }
1103 else 1241 else
1242 {
1104 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1243 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1244 dns->tw.start (60.);
1245 }
1105 } 1246 }
1106 else 1247 else
1107 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1248 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1108 ip [0], ip [1], ip [2], ip [3]); 1249 ip [0], ip [1], ip [2], ip [3]);
1109 1250
… …
1133 break; 1274 break;
1134 } 1275 }
1135} 1276}
1136 1277
1137void 1278void
1138vpn::dnsv4_ev (io_watcher &w, short revents) 1279vpn::dnsv4_ev (ev::io &w, int revents)
1139{ 1280{
1140 if (revents & EVENT_READ) 1281 if (revents & EV_READ)
1141 { 1282 {
1142 dns_packet *pkt = new dns_packet; 1283 dns_packet *pkt = new dns_packet;
1143 struct sockaddr_in sa; 1284 struct sockaddr_in sa;
1144 socklen_t sa_len = sizeof (sa); 1285 socklen_t sa_len = sizeof (sa);
1145 1286
1146 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1287 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1147 1288
1148 if (pkt->len > 0) 1289 if (pkt->len > 0)
1149 { 1290 {
1150 if (THISNODE->dns_port) 1291 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1292 dnsv4_client (*pkt);
1293 else
1151 { 1294 {
1152 dnsv4_server (*pkt); 1295 dnsv4_server (*pkt);
1153 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1296 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1154 } 1297 }
1155 else
1156 dnsv4_client (*pkt);
1157 1298
1158 delete pkt; 1299 delete pkt;
1159 } 1300 }
1160 } 1301 }
1161} 1302}
1162 1303
1163bool 1304bool
1164vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1305vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1165{ 1306{
1166 int client = ntohs (si.port); 1307 int client = ntohl (si.host);
1167 1308
1168 assert (0 < client && client <= conns.size ()); 1309 assert (0 < client && client <= conns.size ());
1169 1310
1170 connection *c = conns [client - 1]; 1311 connection *c = conns [client - 1];
1171 1312
1172 if (!c->dns) 1313 if (!c->dns)
1173 c->dns = new dns_connection (c); 1314 c->dns = new dns_connection (c);
1174 1315
1175 if (!c->dns->snddq.put (pkt)) 1316 if (c->dns->snddq.put (pkt))
1176 return false; 1317 {
1318 min_it (c->dns->poll_interval, 0.25);
1319 c->dns->tw ();
1320 }
1177 1321
1178 c->dns->tw.trigger (); 1322 // always return true even if the buffer overflows
1179
1180 return true; 1323 return true;
1181} 1324}
1182 1325
1183void 1326void
1184connection::dnsv4_reset_connection () 1327dns_connection::time_cb (ev::timer &w, int revents)
1185{
1186 //delete dns; dns = 0; //TODO
1187}
1188
1189#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1190
1191void
1192dns_connection::time_cb (time_watcher &w)
1193{ 1328{
1194 // servers have to be polled 1329 // servers have to be polled
1195 if (THISNODE->dns_port) 1330 if (THISNODE->dns_port)
1196 return; 1331 return;
1197 1332
1198 // check for timeouts and (re)transmit 1333 // check for timeouts and (re)transmit
1199 tstamp next = NOW + poll_interval; 1334 tstamp next = 86400 * 365;
1200 dns_snd *send = 0; 1335 dns_snd *send = 0;
1201 1336
1202 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1337 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1203 i != vpn->dns_sndpq.end (); 1338 i != vpn->dns_sndpq.end ();
1204 ++i) 1339 ++i)
1205 { 1340 {
1206 dns_snd *r = *i; 1341 dns_snd *r = *i;
1207 1342
1208 if (r->timeout <= NOW) 1343 if (r->timeout <= ev_now ())
1209 { 1344 {
1210 if (!send) 1345 if (!send)
1211 { 1346 {
1212 send = r; 1347 send = r;
1213 1348
1214 r->retry++; 1349 r->retry++;
1215 r->timeout = NOW + (r->retry * last_latency * 8.); 1350 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1351 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1216 1352
1217 // the following code changes the query section a bit, forcing 1353 // the following code changes the query section a bit, forcing
1218 // the forwarder to generate a new request 1354 // the forwarder to generate a new request
1219 if (r->stdhdr) 1355 if (r->stdhdr)
1220 {
1221 //printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1222 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1356 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1223 }
1224 } 1357 }
1225 } 1358 }
1226 else 1359 else
1227 NEXT (r->timeout); 1360 min_it (next, r->timeout - ev_now ());
1228 }
1229
1230 if (last_sent + send_interval <= NOW)
1231 { 1361 }
1362
1232 if (!send) 1363 if (!send)
1364 {
1365 // generate a new packet, if wise
1366
1367 if (!established)
1233 { 1368 {
1234 // generate a new packet, if wise 1369 if (vpn->dns_sndpq.empty ())
1235
1236 if (!established)
1237 { 1370 {
1238 if (vpn->dns_sndpq.empty ())
1239 {
1240 send = new dns_snd (this); 1371 send = new dns_snd (this);
1241 1372
1242 printf ("new conn %p %d\n", this, c->conf->id);//D
1243 cfg.reset (THISNODE->id); 1373 cfg.reset (THISNODE->id);
1374 set_cfg ();
1244 send->gen_syn_req (); 1375 send->gen_syn_req ();
1245 }
1246 } 1376 }
1247 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1377 }
1378 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1248 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1379 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1380 {
1381 if (last_sent + send_interval <= ev_now ())
1249 { 1382 {
1250 //printf ("sending data request etc.\n"); //D 1383 //printf ("sending data request etc.\n"); //D
1251 if (!snddq.empty ()) 1384 if (!snddq.empty ())
1252 {
1253 poll_interval = send_interval;
1254 NEXT (NOW + send_interval); 1385 min_it (next, send_interval);
1255 }
1256 1386
1257 send = new dns_snd (this); 1387 send = new dns_snd (this);
1258 send->gen_stream_req (sndseq, snddq); 1388 send->gen_stream_req (sndseq, snddq);
1259 send->timeout = NOW + last_latency * 8.; 1389 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1390 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1260 1391
1261 sndseq = (sndseq + 1) & SEQNO_MASK; 1392 sndseq = (sndseq + 1) & SEQNO_MASK;
1262 } 1393 }
1263 1394 else
1264 if (send) 1395 min_it (next, last_sent + send_interval - ev_now ());
1265 vpn->dns_sndpq.push_back (send);
1266 } 1396 }
1267 1397
1268 if (send) 1398 if (send)
1269 { 1399 vpn->dns_sndpq.push_back (send);
1270 last_sent = NOW; 1400 }
1401
1402 if (send)
1403 {
1404 last_sent = ev_now ();
1271 sendto (vpn->dnsv4_fd, 1405 sendto (vpn->dnsv4_fd,
1272 send->pkt->at (0), send->pkt->len, 0, 1406 send->pkt->at (0), send->pkt->len, 0,
1273 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1407 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1274 }
1275 } 1408 }
1276 else
1277 NEXT (last_sent + send_interval);
1278 1409
1410 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1411
1279 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1412 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1280 poll_interval, send_interval, next - NOW, 1413 poll_interval, send_interval, next - ev_now (),
1281 vpn->dns_sndpq.size (), snddq.size ()); 1414 vpn->dns_sndpq.size (), snddq.size (),
1282 1415 rcvpq.size ());
1283 // TODO: no idea when this happens, but when next < NOW, we have a problem
1284 if (next < NOW + 0.0001)
1285 next = NOW + 0.1;
1286 1416
1287 w.start (next); 1417 w.start (next);
1288} 1418}
1289 1419
1290#endif 1420#endif

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