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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 1.52 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;
… …
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 ()
515{
516 if (!dns_id) 595 if (!dns_id)
517 dns_id = time (0); 596 dns_id = time (0);
518 597
519 // the simplest lsfr with periodicity 65535 i could find 598 // the simplest lsfr with periodicity 65535 i could find
520 dns_id = (dns_id << 1) 599 dns_id = (dns_id << 1)
… …
535 struct vpn *vpn; 614 struct vpn *vpn;
536 615
537 dns_cfg cfg; 616 dns_cfg cfg;
538 617
539 bool established; 618 bool established;
619 const basecoder *cdc;
540 620
541 tstamp last_received; 621 tstamp last_received;
542 tstamp last_sent; 622 tstamp last_sent;
543 double last_latency; 623 double min_latency;
544 double poll_interval, send_interval; 624 double poll_interval, send_interval;
545 625
546 vector<dns_rcv *> rcvpq; 626 vector<dns_rcv *> rcvpq;
547 627
548 byte_stream rcvdq; int rcvseq; 628 byte_stream rcvdq; int rcvseq; int repseq;
549 byte_stream snddq; int sndseq; 629 byte_stream snddq; int sndseq;
550 630
551 void time_cb (time_watcher &w); time_watcher tw; 631 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
552 void receive_rep (dns_rcv *r); 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
553 636
554 dns_connection (connection *c); 637 dns_connection (connection *c);
555 ~dns_connection (); 638 ~dns_connection ();
556}; 639};
557 640
… …
575: dns (dns) 658: dns (dns)
576{ 659{
577 timeout = 0; 660 timeout = 0;
578 retry = 0; 661 retry = 0;
579 seqno = 0; 662 seqno = 0;
580 sent = NOW; 663 sent = ev_now ();
581 stdhdr = false; 664 stdhdr = false;
582 665
583 pkt = new dns_packet; 666 pkt = new dns_packet;
584 667
585 pkt->id = next_id (); 668 pkt->id = next_id ();
… …
588dns_snd::~dns_snd () 671dns_snd::~dns_snd ()
589{ 672{
590 delete pkt; 673 delete pkt;
591} 674}
592 675
676static void
593static void append_domain (dns_packet &pkt, int &offs, const char *domain) 677append_domain (dns_packet &pkt, int &offs, const char *domain)
594{ 678{
595 // add tunnel domain 679 // add tunnel domain
596 for (;;) 680 for (;;)
597 { 681 {
598 const char *end = strchr (domain, '.'); 682 const char *end = strchr (domain, '.');
… …
611 695
612 domain = end + 1; 696 domain = end + 1;
613 } 697 }
614} 698}
615 699
700void
616void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 701dns_snd::gen_stream_req (int seqno, byte_stream &stream)
617{ 702{
618 stdhdr = true; 703 stdhdr = true;
619 this->seqno = seqno; 704 this->seqno = seqno;
620 705
621 timeout = NOW + INITIAL_TIMEOUT; 706 timeout = ev_now () + INITIAL_TIMEOUT;
622 707
623 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 708 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
624 pkt->qdcount = htons (1); 709 pkt->qdcount = htons (1);
625 710
626 int offs = 6*2; 711 int offs = 6*2;
627 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 712 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, 713 // 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 714 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
630 715
631 char enc[256], *encp = enc; 716 char enc[256], *encp = enc;
632 encode_header (enc, THISNODE->id, seqno); 717 encode_header (enc, THISNODE->id, seqno);
633 718
634 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);
635 720
636 if (datalen > stream.size ()) 721 if (datalen > stream.size ())
637 datalen = stream.size (); 722 datalen = stream.size ();
638 723
639 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 724 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
640 stream.remove (datalen); 725 stream.remove (datalen);
641 726
642 while (enclen) 727 while (enclen)
643 { 728 {
644 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 729 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
650 encp += lbllen; 735 encp += lbllen;
651 736
652 enclen -= lbllen; 737 enclen -= lbllen;
653 } 738 }
654 739
655 append_domain (*pkt, offs, THISNODE->domain); 740 append_domain (*pkt, offs, dns->c->conf->domain);
656 741
657 (*pkt)[offs++] = 0; 742 (*pkt)[offs++] = 0;
658 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 743 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
659 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 744 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
660 745
661 pkt->len = offs; 746 pkt->len = offs;
662} 747}
663 748
749void
664void dns_snd::gen_syn_req () 750dns_snd::gen_syn_req ()
665{ 751{
666 timeout = NOW + INITIAL_SYN_TIMEOUT; 752 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
667
668 printf ("send syn\n");//D
669 753
670 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 754 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
671 pkt->qdcount = htons (1); 755 pkt->qdcount = htons (1);
672 756
673 int offs = 6 * 2; 757 int offs = 6 * 2;
… …
676 760
677 assert (elen <= MAX_LBL_SIZE); 761 assert (elen <= MAX_LBL_SIZE);
678 762
679 (*pkt)[offs] = elen; 763 (*pkt)[offs] = elen;
680 offs += elen + 1; 764 offs += elen + 1;
681 append_domain (*pkt, offs, THISNODE->domain); 765 append_domain (*pkt, offs, dns->c->conf->domain);
682 766
683 (*pkt)[offs++] = 0; 767 (*pkt)[offs++] = 0;
684 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 768 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
685 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 769 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
686 770
… …
712///////////////////////////////////////////////////////////////////////////// 796/////////////////////////////////////////////////////////////////////////////
713 797
714dns_connection::dns_connection (connection *c) 798dns_connection::dns_connection (connection *c)
715: c (c) 799: c (c)
716, rcvdq (MAX_BACKLOG * 2) 800, rcvdq (MAX_BACKLOG * 2)
717, snddq (MAX_BACKLOG * 2) 801, snddq (MAX_BACKLOG)
718, tw (this, &dns_connection::time_cb)
719{ 802{
803 tw.set<dns_connection, &dns_connection::time_cb> (this);
804
720 vpn = c->vpn; 805 vpn = c->vpn;
721 806
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
722 established = false; 831 established = false;
723 832
724 rcvseq = sndseq = 0; 833 rcvseq = repseq = sndseq = 0;
725 834
726 last_sent = last_received = 0; 835 last_sent = 0;
727 poll_interval = MIN_POLL_INTERVAL; 836 poll_interval = 0.5; // starting here
728 send_interval = 0.5; // starting rate 837 send_interval = 0.5; // starting rate
729 last_latency = INITIAL_TIMEOUT; 838 min_latency = INITIAL_TIMEOUT;
730} 839}
731 840
732dns_connection::~dns_connection () 841void
842dns_connection::set_cfg ()
733{ 843{
734 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 844 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
735 i != rcvpq.end ();
736 ++i)
737 delete *i;
738} 845}
739 846
847void
740void dns_connection::receive_rep (dns_rcv *r) 848dns_connection::receive_rep (dns_rcv *r)
741{ 849{
742 if (r->datalen) 850 if (r->datalen)
743 { 851 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 852 else
750 { 853 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 }
755 854
756 rcvpq.push_back (r); 855 rcvpq.push_back (r);
757 856
758 redo: 857 redo:
759 858
760 // find next packet 859 // find next packet
761 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 860 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
762 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 861 if (SEQNO_EQ (rcvseq, (*i)->seqno))
763 { 862 {
863 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
764 // enter the packet into our input stream 864 // enter the packet into our input stream
765 r = *i; 865 r = *i;
766 866
767 // remove the oldest packet, look forward, as it's oldest first 867 // remove the oldest packet, look forward, as it's oldest first
768 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)
769 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 869 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
770 { 870 {
871 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
771 delete *j; 872 delete *j;
772 rcvpq.erase (j); 873 rcvpq.erase (j);
773 break; 874 break;
774 } 875 }
775 876
776 rcvseq = (rcvseq + 1) & SEQNO_MASK; 877 rcvseq = (rcvseq + 1) & SEQNO_MASK;
777 878
778 if (!rcvdq.put (r->data, r->datalen)) 879 if (!rcvdq.put (r->data, r->datalen))
779 { 880 {
881 // MUST never overflow, can be caused by data corruption, TODO
780 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 882 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
781 abort (); // MUST never overflow, can be caused by data corruption, TODO 883 reset ();
884 return;
782 } 885 }
783 886
784 while (vpn_packet *pkt = rcvdq.get ()) 887 while (vpn_packet *pkt = rcvdq.get ())
785 { 888 {
786 sockinfo si; 889 sockinfo si;
787 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 890 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
788 891
789 vpn->recv_vpn_packet (pkt, si); 892 vpn->recv_vpn_packet (pkt, si);
790
791 delete pkt; 893 delete pkt;
792 } 894 }
793 895
794 // check for further packets 896 // check for further packets
795 goto redo; 897 goto redo;
… …
806 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 908 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
807 909
808 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 910 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
809 && pkt.qdcount == htons (1)) 911 && pkt.qdcount == htons (1))
810 { 912 {
811 char qname[MAXSIZE]; 913 char qname [MAXSIZE];
812 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 914 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
813 915
814 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 916 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
815 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 917 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
816 918
… …
823 925
824 int dlen = strlen (THISNODE->domain); 926 int dlen = strlen (THISNODE->domain);
825 927
826 if (qclass == RR_CLASS_IN 928 if (qclass == RR_CLASS_IN
827 && qlen > dlen + 1 929 && qlen > dlen + 1
828 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 930 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
829 { 931 {
830 // now generate reply 932 // now generate reply
831 pkt.ancount = htons (1); // one answer RR 933 pkt.ancount = htons (1); // one answer RR
832 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 934 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
833 935
… …
838 { 940 {
839 // correct class, domain: parse 941 // correct class, domain: parse
840 int client, seqno; 942 int client, seqno;
841 decode_header (qname, client, seqno); 943 decode_header (qname, client, seqno);
842 944
843 u8 data[MAXSIZE];
844 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
845
846 if (0 < client && client <= conns.size ()) 945 if (0 < client && client <= conns.size ())
847 { 946 {
848 connection *c = conns [client - 1]; 947 connection *c = conns [client - 1];
849 dns_connection *dns = c->dns; 948 dns_connection *dns = c->dns;
850 dns_rcv *rcv; 949 dns_rcv *rcv;
851 bool in_seq;
852 950
853 if (dns) 951 if (dns)
854 { 952 {
953 u8 data[MAXSIZE];
954 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
955
855 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 (); )
856 if (SEQNO_EQ ((*i)->seqno, seqno)) 957 if (SEQNO_EQ ((*i)->seqno, seqno))
857 { 958 {
858 // already seen that request: simply reply with the cached reply 959 // already seen that request: simply reply with the cached reply
859 dns_rcv *r = *i; 960 dns_rcv *r = *i;
… …
867 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);
868 969
869 goto duplicate_request; 970 goto duplicate_request;
870 } 971 }
871 972
872 in_seq = dns->rcvseq == seqno;
873
874 // new packet, queue 973 // new packet, queue
875 rcv = new dns_rcv (seqno, data, datalen); 974 rcv = new dns_rcv (seqno, data, datalen);
876 dns->receive_rep (rcv); 975 dns->receive_rep (rcv);
877 } 976 }
878 977
978 {
879 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
880 980
881 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 981 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
882 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 982 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
883 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
884 pkt [offs++] = 0; pkt [offs++] = 0; 984 pkt [offs++] = 0; pkt [offs++] = 0;
885 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
886 986
887 int rdlen_offs = offs += 2; 987 int rdlen_offs = offs += 2;
888 988
989 if (dns)
990 {
889 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 991 int dlen = ntohs (dns->cfg.max_size) - offs;
992
890 // 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
891 dlen -= qlen; 994 dlen -= qlen;
892 995
893 if (dns)
894 {
895 // only put data into in-order sequence packets, if 996 // only put data into in-order sequence packets, if
896 // we receive out-of-order packets we generate empty 997 // we receive out-of-order packets we generate empty
897 // replies 998 // replies
898 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)
899 { 1001 {
1002 dns->repseq = seqno;
1003
1004 while (dlen > 1 && !dns->snddq.empty ())
1005 {
900 int txtlen = dlen <= 255 ? dlen - 1 : 255; 1006 int txtlen = dlen <= 255 ? dlen - 1 : 255;
901 1007
902 if (txtlen > dns->snddq.size ()) 1008 if (txtlen > dns->snddq.size ())
903 txtlen = dns->snddq.size (); 1009 txtlen = dns->snddq.size ();
904 1010
905 pkt[offs++] = txtlen; 1011 pkt[offs++] = txtlen;
906 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 1012 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
907 offs += txtlen; 1013 offs += txtlen;
908 dns->snddq.remove (txtlen); 1014 dns->snddq.remove (txtlen);
909 1015
910 dlen -= txtlen + 1; 1016 dlen -= txtlen + 1;
1017 }
911 } 1018 }
912 1019
913 // avoid empty TXT rdata 1020 // avoid completely empty TXT rdata
914 if (offs == rdlen_offs) 1021 if (offs == rdlen_offs)
915 pkt[offs++] = 0; 1022 pkt[offs++] = 0;
916 1023
917 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 1024 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
918 } 1025 }
919 else 1026 else
920 { 1027 {
921 // send RST 1028 // send RST
922 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;
923 pkt [offs++] = CMD_IP_RST; 1030 pkt [offs++] = CMD_IP_RST;
924 } 1031 }
925 1032
926 int rdlen = offs - rdlen_offs; 1033 int rdlen = offs - rdlen_offs;
927 1034
928 pkt [rdlen_offs - 2] = rdlen >> 8; 1035 pkt [rdlen_offs - 2] = rdlen >> 8;
929 pkt [rdlen_offs - 1] = rdlen; 1036 pkt [rdlen_offs - 1] = rdlen;
930 1037
931 if (dns) 1038 if (dns)
932 { 1039 {
933 // now update dns_rcv copy 1040 // now update dns_rcv copy
934 rcv->pkt->len = offs; 1041 rcv->pkt->len = offs;
935 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 1042 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
936 } 1043 }
1044 }
937 1045
938 duplicate_request: ; 1046 duplicate_request: ;
939 } 1047 }
940 else 1048 else
941 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 1049 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
953 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
954 pkt [offs++] = 0; pkt [offs++] = 0; 1062 pkt [offs++] = 0; pkt [offs++] = 0;
955 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1063 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
956 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1064 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
957 1065
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; 1066 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
961 pkt [offs++] = CMD_IP_REJ; 1067 pkt [offs++] = CMD_IP_REJ;
962 1068
963 if (0 < client && client <= conns.size ()) 1069 if (0 < client && client <= conns.size ())
964 { 1070 {
965 connection *c = conns [client - 1]; 1071 connection *c = conns [client - 1];
966 1072
967 if (cfg.valid ()) 1073 if (cfg.valid ())
968 { 1074 {
969 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));
970 1080
971 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
972 c->dns = new dns_connection (c); 1086 c->dns = new dns_connection (c);
973 c->dns->cfg = cfg; 1087 c->dns->cfg = cfg;
1088 c->dns->set_cfg ();
974 } 1089 }
975 } 1090 }
976 } 1091 }
977 } 1092 }
978 1093
… …
997 { 1112 {
998 dns_connection *dns = (*i)->dns; 1113 dns_connection *dns = (*i)->dns;
999 connection *c = dns->c; 1114 connection *c = dns->c;
1000 int seqno = (*i)->seqno; 1115 int seqno = (*i)->seqno;
1001 u8 data[MAXSIZE], *datap = data; 1116 u8 data[MAXSIZE], *datap = data;
1117 //printf ("rcv pkt %x\n", seqno);//D
1002 1118
1003 if ((*i)->retry) 1119 if ((*i)->retry)
1004 { 1120 {
1005 dns->send_interval *= 1.01; 1121 dns->send_interval *= 1.01;
1006 if (dns->send_interval > MAX_SEND_INTERVAL) 1122 if (dns->send_interval > MAX_SEND_INTERVAL)
1007 dns->send_interval = MAX_SEND_INTERVAL; 1123 dns->send_interval = MAX_SEND_INTERVAL;
1008 } 1124 }
1009 else 1125 else
1010 { 1126 {
1011#if 1 1127#if 0
1012 dns->send_interval *= 0.999; 1128 dns->send_interval *= 0.999;
1013#endif 1129#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 1130 // the latency surely puts an upper bound on
1018 // the minimum send interval 1131 // the minimum send interval
1019 double latency = NOW - (*i)->sent; 1132 double latency = ev_now () - (*i)->sent;
1133
1134 if (latency < dns->min_latency)
1020 dns->last_latency = latency; 1135 dns->min_latency = latency;
1021 1136
1022 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)
1023 dns->send_interval = latency; 1141 dns->send_interval = conf.dns_send_interval;
1024 } 1142 }
1025 1143
1026 delete *i; 1144 delete *i;
1027 dns_sndpq.erase (i); 1145 dns_sndpq.erase (i);
1028 1146
… …
1046 ttl |= pkt [offs++] << 16; 1164 ttl |= pkt [offs++] << 16;
1047 ttl |= pkt [offs++] << 8; 1165 ttl |= pkt [offs++] << 8;
1048 ttl |= pkt [offs++]; 1166 ttl |= pkt [offs++];
1049 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1167 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1050 1168
1051 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1169 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1052 { 1170 {
1053 if (rdlen <= MAXSIZE - offs) 1171 if (rdlen <= MAXSIZE - offs)
1054 { 1172 {
1055 // decode bytes, finally 1173 // decode bytes, finally
1056 1174
… …
1082 { 1200 {
1083 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1201 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1084 1202
1085 if (ip [3] == CMD_IP_RST) 1203 if (ip [3] == CMD_IP_RST)
1086 { 1204 {
1087 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1205 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1088 1206
1089 delete dns; c->dns = 0; 1207 dns->reset ();
1090
1091 return; 1208 return;
1092 } 1209 }
1093 else if (ip [3] == CMD_IP_SYN) 1210 else if (ip [3] == CMD_IP_SYN)
1094 { 1211 {
1095 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1212 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1096 dns->established = true; 1213 dns->established = true;
1097 } 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 }
1098 else if (ip [3] == CMD_IP_REJ) 1230 else if (ip [3] == CMD_IP_REJ)
1099 { 1231 {
1100 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."));
1101 abort (); 1233 dns->tw.start (60.);
1102 } 1234 }
1103 else 1235 else
1236 {
1104 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 }
1105 } 1240 }
1106 else 1241 else
1107 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"),
1108 ip [0], ip [1], ip [2], ip [3]); 1243 ip [0], ip [1], ip [2], ip [3]);
1109 1244
… …
1133 break; 1268 break;
1134 } 1269 }
1135} 1270}
1136 1271
1137void 1272void
1138vpn::dnsv4_ev (io_watcher &w, short revents) 1273vpn::dnsv4_ev (ev::io &w, int revents)
1139{ 1274{
1140 if (revents & EVENT_READ) 1275 if (revents & EV_READ)
1141 { 1276 {
1142 dns_packet *pkt = new dns_packet; 1277 dns_packet *pkt = new dns_packet;
1143 struct sockaddr_in sa; 1278 struct sockaddr_in sa;
1144 socklen_t sa_len = sizeof (sa); 1279 socklen_t sa_len = sizeof (sa);
1145 1280
1146 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);
1147 1282
1148 if (pkt->len > 0) 1283 if (pkt->len > 0)
1149 { 1284 {
1150 if (THISNODE->dns_port) 1285 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1286 dnsv4_client (*pkt);
1287 else
1151 { 1288 {
1152 dnsv4_server (*pkt); 1289 dnsv4_server (*pkt);
1153 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);
1154 } 1291 }
1155 else
1156 dnsv4_client (*pkt);
1157 1292
1158 delete pkt; 1293 delete pkt;
1159 } 1294 }
1160 } 1295 }
1161} 1296}
1162 1297
1163bool 1298bool
1164vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1299vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1165{ 1300{
1166 int client = ntohs (si.port); 1301 int client = ntohl (si.host);
1167 1302
1168 assert (0 < client && client <= conns.size ()); 1303 assert (0 < client && client <= conns.size ());
1169 1304
1170 connection *c = conns [client - 1]; 1305 connection *c = conns [client - 1];
1171 1306
1172 if (!c->dns) 1307 if (!c->dns)
1173 c->dns = new dns_connection (c); 1308 c->dns = new dns_connection (c);
1174 1309
1175 if (!c->dns->snddq.put (pkt)) 1310 if (c->dns->snddq.put (pkt))
1176 return false; 1311 {
1312 min_it (c->dns->poll_interval, 0.25);
1313 c->dns->tw ();
1314 }
1177 1315
1178 c->dns->tw.trigger (); 1316 // always return true even if the buffer overflows
1179
1180 return true; 1317 return true;
1181} 1318}
1182 1319
1183void 1320void
1184connection::dnsv4_reset_connection () 1321dns_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{ 1322{
1194 // servers have to be polled 1323 // servers have to be polled
1195 if (THISNODE->dns_port) 1324 if (THISNODE->dns_port)
1196 return; 1325 return;
1197 1326
1198 // check for timeouts and (re)transmit 1327 // check for timeouts and (re)transmit
1199 tstamp next = NOW + poll_interval; 1328 tstamp next = 86400 * 365;
1200 dns_snd *send = 0; 1329 dns_snd *send = 0;
1201 1330
1202 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1331 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1203 i != vpn->dns_sndpq.end (); 1332 i != vpn->dns_sndpq.end ();
1204 ++i) 1333 ++i)
1205 { 1334 {
1206 dns_snd *r = *i; 1335 dns_snd *r = *i;
1207 1336
1208 if (r->timeout <= NOW) 1337 if (r->timeout <= ev_now ())
1209 { 1338 {
1210 if (!send) 1339 if (!send)
1211 { 1340 {
1212 send = r; 1341 send = r;
1213 1342
1214 r->retry++; 1343 r->retry++;
1215 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
1216 1346
1217 // the following code changes the query section a bit, forcing 1347 // the following code changes the query section a bit, forcing
1218 // the forwarder to generate a new request 1348 // the forwarder to generate a new request
1219 if (r->stdhdr) 1349 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); 1350 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1223 }
1224 } 1351 }
1225 } 1352 }
1226 else 1353 else
1227 NEXT (r->timeout); 1354 min_it (next, r->timeout - ev_now ());
1228 }
1229
1230 if (last_sent + send_interval <= NOW)
1231 { 1355 }
1356
1232 if (!send) 1357 if (!send)
1358 {
1359 // generate a new packet, if wise
1360
1361 if (!established)
1233 { 1362 {
1234 // generate a new packet, if wise 1363 if (vpn->dns_sndpq.empty ())
1235
1236 if (!established)
1237 { 1364 {
1238 if (vpn->dns_sndpq.empty ())
1239 {
1240 send = new dns_snd (this); 1365 send = new dns_snd (this);
1241 1366
1242 printf ("new conn %p %d\n", this, c->conf->id);//D
1243 cfg.reset (THISNODE->id); 1367 cfg.reset (THISNODE->id);
1368 set_cfg ();
1244 send->gen_syn_req (); 1369 send->gen_syn_req ();
1245 }
1246 } 1370 }
1247 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1371 }
1372 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1248 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1373 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1374 {
1375 if (last_sent + send_interval <= ev_now ())
1249 { 1376 {
1250 //printf ("sending data request etc.\n"); //D 1377 //printf ("sending data request etc.\n"); //D
1251 if (!snddq.empty ()) 1378 if (!snddq.empty ())
1252 {
1253 poll_interval = send_interval;
1254 NEXT (NOW + send_interval); 1379 min_it (next, send_interval);
1255 }
1256 1380
1257 send = new dns_snd (this); 1381 send = new dns_snd (this);
1258 send->gen_stream_req (sndseq, snddq); 1382 send->gen_stream_req (sndseq, snddq);
1259 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
1260 1385
1261 sndseq = (sndseq + 1) & SEQNO_MASK; 1386 sndseq = (sndseq + 1) & SEQNO_MASK;
1262 } 1387 }
1263 1388 else
1264 if (send) 1389 min_it (next, last_sent + send_interval - ev_now ());
1265 vpn->dns_sndpq.push_back (send);
1266 } 1390 }
1267 1391
1268 if (send) 1392 if (send)
1269 { 1393 vpn->dns_sndpq.push_back (send);
1270 last_sent = NOW; 1394 }
1395
1396 if (send)
1397 {
1398 last_sent = ev_now ();
1271 sendto (vpn->dnsv4_fd, 1399 sendto (vpn->dnsv4_fd,
1272 send->pkt->at (0), send->pkt->len, 0, 1400 send->pkt->at (0), send->pkt->len, 0,
1273 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1401 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1274 }
1275 } 1402 }
1276 else
1277 NEXT (last_sent + send_interval);
1278 1403
1404 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1405
1279 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)",
1280 poll_interval, send_interval, next - NOW, 1407 poll_interval, send_interval, next - ev_now (),
1281 vpn->dns_sndpq.size (), snddq.size ()); 1408 vpn->dns_sndpq.size (), snddq.size (),
1282 1409 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 1410
1287 w.start (next); 1411 w.start (next);
1288} 1412}
1289 1413
1290#endif 1414#endif

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