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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.22 by pcg, Sun Mar 6 21:47:35 2005 UTC vs.
Revision 1.50 by root, Sun Mar 6 13:49:50 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) 2003-2008 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
… …
38#include <unistd.h> 52#include <unistd.h>
39#include <fcntl.h> 53#include <fcntl.h>
40 54
41#include <map> 55#include <map>
42 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
43#include <gmp.h> 58#include <gmp.h>
44 59
45#include "netcompat.h" 60#include "netcompat.h"
46 61
47#include "vpn.h" 62#include "vpn.h"
48 63
49#define MIN_POLL_INTERVAL .02 // how often to poll minimally when the server has data
50#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data 64#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
51#define ACTIVITY_INTERVAL 5. 65#define ACTIVITY_INTERVAL 5.
52 66
53#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
54#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
55 69
56#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
57#define MAX_SEND_INTERVAL 0.5 // optimistic? 70#define MAX_SEND_INTERVAL 2. // optimistic?
58 71
59#define MAX_OUTSTANDING 10 // max. outstanding requests
60#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
61#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
62 74
63#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
64// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
65// every two request bytes less give room for one reply byte 77// every request byte less give room for two reply bytes
66 78
67#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
68#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
69 81
70#define MAX_LBL_SIZE 63 82#define MAX_LBL_SIZE 63
71#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
72 84
73#define RR_TYPE_A 1 85#define RR_TYPE_A 1
74#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
75#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
76#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
77 90
78#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
79 92
80#define CMD_IP_1 207 93#define CMD_IP_1 207
… …
104 memset (enc, (char) 0, 256); 117 memset (enc, (char) 0, 256);
105 memset (dec, (char)INVALID, 256); 118 memset (dec, (char)INVALID, 256);
106 119
107 for (size = 0; cmap [size]; size++) 120 for (size = 0; cmap [size]; size++)
108 { 121 {
122 char c = cmap [size];
123
109 enc [size] = cmap [size]; 124 enc [size] = c;
110 dec [(u8)enc [size]] = size; 125 dec [(u8)c] = size;
126
127 // allow lowercase/uppercase aliases if possible
128 if (c >= 'A' && c <= 'Z' && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size;
129 if (c >= 'a' && c <= 'z' && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size;
111 } 130 }
112 131
113 assert (size < 256); 132 assert (size < 256);
114} 133}
115 134
… …
155 enc_len [len] = n; 174 enc_len [len] = n;
156 dec_len [n] = len; 175 dec_len [n] = len;
157 } 176 }
158} 177}
159 178
179unsigned int
160unsigned int basecoder::encode_len (unsigned int len) 180basecoder::encode_len (unsigned int len)
161{ 181{
162 return enc_len [len]; 182 return enc_len [len];
163} 183}
164 184
185unsigned int
165unsigned int basecoder::decode_len (unsigned int len) 186basecoder::decode_len (unsigned int len)
166{ 187{
167 while (len && !dec_len [len]) 188 while (len && !dec_len [len])
168 --len; 189 --len;
169 190
170 return dec_len [len]; 191 return dec_len [len];
171} 192}
172 193
194unsigned int
173unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 195basecoder::encode (char *dst, u8 *src, unsigned int len)
174{ 196{
175 if (!len || len > MAX_DEC_LEN) 197 if (!len || len > MAX_DEC_LEN)
176 return 0; 198 return 0;
177 199
178 int elen = encode_len (len); 200 int elen = encode_len (len);
… …
197 *dst++ = cmap.encode [dst_ [i]]; 219 *dst++ = cmap.encode [dst_ [i]];
198 220
199 return elen; 221 return elen;
200} 222}
201 223
224unsigned int
202unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 225basecoder::decode (u8 *dst, char *src, unsigned int len)
203{ 226{
204 if (!len || len > MAX_ENC_LEN) 227 if (!len || len > MAX_ENC_LEN)
205 return 0; 228 return 0;
206 229
207 u8 src_ [MAX_ENC_LEN]; 230 u8 src_ [MAX_ENC_LEN];
… …
265static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 288static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
266 289
267///////////////////////////////////////////////////////////////////////////// 290/////////////////////////////////////////////////////////////////////////////
268 291
269#define HDRSIZE 6 292#define HDRSIZE 6
270 293
294inline void
271inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 295encode_header (char *data, int clientid, int seqno, int retry = 0)
272{ 296{
273 seqno &= SEQNO_MASK; 297 seqno &= SEQNO_MASK;
274 298
275 u8 hdr[3] = { 299 u8 hdr[3] = {
276 clientid, 300 clientid,
… …
281 assert (clientid < 256); 305 assert (clientid < 256);
282 306
283 cdc26.encode (data, hdr, 3); 307 cdc26.encode (data, hdr, 3);
284} 308}
285 309
310inline void
286inline void decode_header (char *data, int &clientid, int &seqno) 311decode_header (char *data, int &clientid, int &seqno)
287{ 312{
288 u8 hdr[3]; 313 u8 hdr[3];
289 314
290 cdc26.decode (hdr, data, HDRSIZE); 315 cdc26.decode (hdr, data, HDRSIZE);
291 316
… …
324byte_stream::~byte_stream () 349byte_stream::~byte_stream ()
325{ 350{
326 delete data; 351 delete data;
327} 352}
328 353
354void
329void byte_stream::remove (int count) 355byte_stream::remove (int count)
330{ 356{
331 if (count > fill) 357 if (count > fill)
332 assert (count <= fill); 358 assert (count <= fill);
333 359
334 memmove (data, data + count, fill -= count); 360 memmove (data, data + count, fill -= count);
335} 361}
336 362
363bool
337bool byte_stream::put (u8 *data, unsigned int datalen) 364byte_stream::put (u8 *data, unsigned int datalen)
338{ 365{
339 if (maxsize - fill < datalen) 366 if (maxsize - fill < datalen)
340 return false; 367 return false;
341 368
342 memcpy (this->data + fill, data, datalen); fill += datalen; 369 memcpy (this->data + fill, data, datalen); fill += datalen;
343 370
344 return true; 371 return true;
345} 372}
346 373
374bool
347bool byte_stream::put (vpn_packet *pkt) 375byte_stream::put (vpn_packet *pkt)
348{ 376{
349 if (maxsize - fill < pkt->len + 2) 377 if (maxsize - fill < pkt->len + 2)
350 return false; 378 return false;
351 379
352 data [fill++] = pkt->len >> 8; 380 data [fill++] = pkt->len >> 8;
… …
409struct dns_cfg 437struct dns_cfg
410{ 438{
411 static int next_uid; 439 static int next_uid;
412 440
413 u8 id1, id2, id3, id4; 441 u8 id1, id2, id3, id4;
442
414 u8 version; 443 u8 version;
444 u8 flags;
415 u8 rrtype; 445 u8 rrtype;
416 u8 flags;
417 u8 def_ttl; 446 u8 def_ttl;
418 u8 rcv_cdc; 447
419 u8 snd_cdc;
420 u16 max_size;
421 u16 client; 448 u16 client;
422 u16 uid; // to make request unique 449 u16 uid; // to make request unique
423 450
424 u8 reserved[8]; 451 u16 max_size;
452 u8 seq_cdc;
453 u8 req_cdc;
454
455 u8 rep_cdc;
456 u8 delay; // time in 0.01s units that the server may delay replying packets
457 u8 r3, r4;
458
459 u8 r5, r6, r7, r8;
425 460
426 void reset (int clientid); 461 void reset (int clientid);
427 bool valid (); 462 bool valid ();
428}; 463};
429 464
430int dns_cfg::next_uid; 465int dns_cfg::next_uid;
431 466
467void
432void dns_cfg::reset (int clientid) 468dns_cfg::reset (int clientid)
433{ 469{
434 id1 = 'G'; 470 id1 = 'G';
435 id2 = 'V'; 471 id2 = 'V';
436 id3 = 'P'; 472 id3 = 'P';
437 id4 = 'E'; 473 id4 = 'E';
438 474
439 version = 1; 475 version = 1;
440 476
441 rrtype = RR_TYPE_TXT; 477 rrtype = RR_TYPE_TXT;
442 flags = 0; 478 flags = 0;
443 def_ttl = 1; 479 def_ttl = 0;
480 seq_cdc = 26;
481 req_cdc = 62;
444 rcv_cdc = 0; 482 rep_cdc = 0;
445 snd_cdc = 62;
446 max_size = ntohs (MAX_PKT_SIZE); 483 max_size = htons (MAX_PKT_SIZE);
447 client = ntohs (clientid); 484 client = htons (clientid);
448 uid = next_uid++; 485 uid = next_uid++;
486 delay = 0;
449 487
450 memset (reserved, 0, 8); 488 r3 = r4 = 0;
489 r4 = r5 = r6 = r7 = 0;
451} 490}
452 491
492bool
453bool dns_cfg::valid () 493dns_cfg::valid ()
454{ 494{
495 // although the protocol itself allows for some configurability,
496 // only the following encoding/decoding settings are implemented.
455 return id1 == 'G' 497 return id1 == 'G'
456 && id2 == 'V' 498 && id2 == 'V'
457 && id3 == 'P' 499 && id3 == 'P'
458 && id4 == 'E' 500 && id4 == 'E'
501 && seq_cdc == 26
502 && req_cdc == 62
503 && rep_cdc == 0
459 && version == 1 504 && version == 1;
460 && flags == 0
461 && rcv_cdc == 0
462 && snd_cdc == 62
463 && max_size == ntohs (MAX_PKT_SIZE);
464} 505}
465 506
466struct dns_packet : net_packet 507struct dns_packet : net_packet
467{ 508{
468 u16 id; 509 u16 id;
469 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 510 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
470 u16 qdcount, ancount, nscount, arcount; 511 u16 qdcount, ancount, nscount, arcount;
471 512
472 u8 data[MAXSIZE - 6 * 2]; 513 u8 data [MAXSIZE - 6 * 2];
473 514
474 int decode_label (char *data, int size, int &offs); 515 int decode_label (char *data, int size, int &offs);
475}; 516};
476 517
518int
477int dns_packet::decode_label (char *data, int size, int &offs) 519dns_packet::decode_label (char *data, int size, int &offs)
478{ 520{
479 char *orig = data; 521 char *orig = data;
480 522
481 memset (data, 0, size); 523 memset (data, 0, size);
482 524
… …
508 return data - orig; 550 return data - orig;
509} 551}
510 552
511///////////////////////////////////////////////////////////////////////////// 553/////////////////////////////////////////////////////////////////////////////
512 554
555static
556u16 next_id ()
557{
513static u16 dns_id = 0; // TODO: should be per-vpn 558 static u16 dns_id = 0; // TODO: should be per-vpn
514 559
515static u16 next_id ()
516{
517 if (!dns_id) 560 if (!dns_id)
518 dns_id = time (0); 561 dns_id = time (0);
519 562
520 // the simplest lsfr with periodicity 65535 i could find 563 // the simplest lsfr with periodicity 65535 i could find
521 dns_id = (dns_id << 1) 564 dns_id = (dns_id << 1)
… …
539 582
540 bool established; 583 bool established;
541 584
542 tstamp last_received; 585 tstamp last_received;
543 tstamp last_sent; 586 tstamp last_sent;
544 double last_latency; 587 double min_latency;
545 double poll_interval, send_interval; 588 double poll_interval, send_interval;
546 589
547 vector<dns_rcv *> rcvpq; 590 vector<dns_rcv *> rcvpq;
548 591
549 byte_stream rcvdq; int rcvseq; 592 byte_stream rcvdq; int rcvseq; int repseq;
550 byte_stream snddq; int sndseq; 593 byte_stream snddq; int sndseq;
551 594
552 void time_cb (time_watcher &w); time_watcher tw; 595 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
553 void receive_rep (dns_rcv *r); 596 void receive_rep (dns_rcv *r);
554 597
555 dns_connection (connection *c); 598 dns_connection (connection *c);
556 ~dns_connection (); 599 ~dns_connection ();
557}; 600};
… …
576: dns (dns) 619: dns (dns)
577{ 620{
578 timeout = 0; 621 timeout = 0;
579 retry = 0; 622 retry = 0;
580 seqno = 0; 623 seqno = 0;
581 sent = NOW; 624 sent = ev_now ();
582 stdhdr = false; 625 stdhdr = false;
583 626
584 pkt = new dns_packet; 627 pkt = new dns_packet;
585 628
586 pkt->id = next_id (); 629 pkt->id = next_id ();
… …
589dns_snd::~dns_snd () 632dns_snd::~dns_snd ()
590{ 633{
591 delete pkt; 634 delete pkt;
592} 635}
593 636
637static void
594static void append_domain (dns_packet &pkt, int &offs, const char *domain) 638append_domain (dns_packet &pkt, int &offs, const char *domain)
595{ 639{
596 // add tunnel domain 640 // add tunnel domain
597 for (;;) 641 for (;;)
598 { 642 {
599 const char *end = strchr (domain, '.'); 643 const char *end = strchr (domain, '.');
… …
612 656
613 domain = end + 1; 657 domain = end + 1;
614 } 658 }
615} 659}
616 660
661void
617void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 662dns_snd::gen_stream_req (int seqno, byte_stream &stream)
618{ 663{
619 stdhdr = true; 664 stdhdr = true;
620 this->seqno = seqno; 665 this->seqno = seqno;
621 666
622 timeout = NOW + INITIAL_TIMEOUT; 667 timeout = ev_now () + INITIAL_TIMEOUT;
623 668
624 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 669 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
625 pkt->qdcount = htons (1); 670 pkt->qdcount = htons (1);
626 671
627 int offs = 6*2; 672 int offs = 6*2;
… …
660 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 705 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
661 706
662 pkt->len = offs; 707 pkt->len = offs;
663} 708}
664 709
710void
665void dns_snd::gen_syn_req () 711dns_snd::gen_syn_req ()
666{ 712{
667 timeout = NOW + INITIAL_SYN_TIMEOUT; 713 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
668 714
669 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 715 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
670 pkt->qdcount = htons (1); 716 pkt->qdcount = htons (1);
671 717
672 int offs = 6 * 2; 718 int offs = 6 * 2;
… …
711///////////////////////////////////////////////////////////////////////////// 757/////////////////////////////////////////////////////////////////////////////
712 758
713dns_connection::dns_connection (connection *c) 759dns_connection::dns_connection (connection *c)
714: c (c) 760: c (c)
715, rcvdq (MAX_BACKLOG * 2) 761, rcvdq (MAX_BACKLOG * 2)
716, snddq (MAX_BACKLOG * 2) 762, snddq (MAX_BACKLOG)
717, tw (this, &dns_connection::time_cb)
718{ 763{
764 tw.set<dns_connection, &dns_connection::time_cb> (this);
765
719 vpn = c->vpn; 766 vpn = c->vpn;
720 767
721 established = false; 768 established = false;
722 769
723 rcvseq = sndseq = 0; 770 rcvseq = repseq = sndseq = 0;
724 771
725 last_sent = last_received = 0; 772 last_sent = last_received = 0;
726 poll_interval = MIN_POLL_INTERVAL; 773 poll_interval = 0.5; // starting here
727 send_interval = 0.5; // starting rate 774 send_interval = 0.5; // starting rate
728 last_latency = INITIAL_TIMEOUT; 775 min_latency = INITIAL_TIMEOUT;
729} 776}
730 777
731dns_connection::~dns_connection () 778dns_connection::~dns_connection ()
732{ 779{
733 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 780 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
734 i != rcvpq.end (); 781 i != rcvpq.end ();
735 ++i) 782 ++i)
736 delete *i; 783 delete *i;
737} 784}
738 785
786void
739void dns_connection::receive_rep (dns_rcv *r) 787dns_connection::receive_rep (dns_rcv *r)
740{ 788{
741 if (r->datalen) 789 if (r->datalen)
742 { 790 {
743 last_received = NOW; 791 last_received = ev_now ();
744 tw.trigger (); 792 tw ();
745 793
746 poll_interval = send_interval; 794 poll_interval = send_interval;
747 } 795 }
748 else 796 else
749 { 797 {
750 poll_interval *= 1.5; 798 poll_interval *= 1.5;
799
751 if (poll_interval > MAX_POLL_INTERVAL) 800 if (poll_interval > MAX_POLL_INTERVAL)
752 poll_interval = MAX_POLL_INTERVAL; 801 poll_interval = MAX_POLL_INTERVAL;
753 } 802 }
754 803
755 rcvpq.push_back (r); 804 rcvpq.push_back (r);
… …
758 807
759 // find next packet 808 // find next packet
760 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 809 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
761 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 810 if (SEQNO_EQ (rcvseq, (*i)->seqno))
762 { 811 {
812 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
763 // enter the packet into our input stream 813 // enter the packet into our input stream
764 r = *i; 814 r = *i;
765 815
766 // remove the oldest packet, look forward, as it's oldest first 816 // remove the oldest packet, look forward, as it's oldest first
767 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 817 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
768 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 818 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
769 { 819 {
820 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
770 delete *j; 821 delete *j;
771 rcvpq.erase (j); 822 rcvpq.erase (j);
772 break; 823 break;
773 } 824 }
774 825
775 rcvseq = (rcvseq + 1) & SEQNO_MASK; 826 rcvseq = (rcvseq + 1) & SEQNO_MASK;
776 827
777 if (!rcvdq.put (r->data, r->datalen)) 828 if (!rcvdq.put (r->data, r->datalen))
778 { 829 {
830 // MUST never overflow, can be caused by data corruption, TODO
779 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 831 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
780 abort (); // MUST never overflow, can be caused by data corruption, TODO 832 c->dnsv4_reset_connection ();
833 return;
781 } 834 }
782 835
783 while (vpn_packet *pkt = rcvdq.get ()) 836 while (vpn_packet *pkt = rcvdq.get ())
784 { 837 {
785 sockinfo si; 838 sockinfo si;
786 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 839 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
787 840
788 vpn->recv_vpn_packet (pkt, si); 841 vpn->recv_vpn_packet (pkt, si);
789
790 delete pkt; 842 delete pkt;
791 } 843 }
792 844
793 // check for further packets 845 // check for further packets
794 goto redo; 846 goto redo;
… …
805 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 857 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
806 858
807 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 859 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
808 && pkt.qdcount == htons (1)) 860 && pkt.qdcount == htons (1))
809 { 861 {
810 char qname[MAXSIZE]; 862 char qname [MAXSIZE];
811 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 863 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
812 864
813 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 865 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
814 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 866 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
815 867
… …
822 874
823 int dlen = strlen (THISNODE->domain); 875 int dlen = strlen (THISNODE->domain);
824 876
825 if (qclass == RR_CLASS_IN 877 if (qclass == RR_CLASS_IN
826 && qlen > dlen + 1 878 && qlen > dlen + 1
827 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 879 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
828 { 880 {
829 // now generate reply 881 // now generate reply
830 pkt.ancount = htons (1); // one answer RR 882 pkt.ancount = htons (1); // one answer RR
831 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 883 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
832 884
… …
845 if (0 < client && client <= conns.size ()) 897 if (0 < client && client <= conns.size ())
846 { 898 {
847 connection *c = conns [client - 1]; 899 connection *c = conns [client - 1];
848 dns_connection *dns = c->dns; 900 dns_connection *dns = c->dns;
849 dns_rcv *rcv; 901 dns_rcv *rcv;
850 bool in_seq;
851 902
852 if (dns) 903 if (dns)
853 { 904 {
854 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 905 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
855 if (SEQNO_EQ ((*i)->seqno, seqno)) 906 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
866 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 917 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
867 918
868 goto duplicate_request; 919 goto duplicate_request;
869 } 920 }
870 921
871 in_seq = dns->rcvseq == seqno;
872
873 // new packet, queue 922 // new packet, queue
874 rcv = new dns_rcv (seqno, data, datalen); 923 rcv = new dns_rcv (seqno, data, datalen);
875 dns->receive_rep (rcv); 924 dns->receive_rep (rcv);
876 } 925 }
877 926
… …
884 pkt [offs++] = 0; pkt [offs++] = 0; 933 pkt [offs++] = 0; pkt [offs++] = 0;
885 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 934 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
886 935
887 int rdlen_offs = offs += 2; 936 int rdlen_offs = offs += 2;
888 937
889 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
890 // bind doesn't compress well, so reduce further by one label length
891 dlen -= qlen;
892
893 if (dns) 938 if (dns)
894 { 939 {
940 int dlen = ntohs (dns->cfg.max_size) - offs;
941
942 // bind doesn't compress well, so reduce further by one label length
943 dlen -= qlen;
944
895 // only put data into in-order sequence packets, if 945 // only put data into in-order sequence packets, if
896 // we receive out-of-order packets we generate empty 946 // we receive out-of-order packets we generate empty
897 // replies 947 // replies
898 while (dlen > 1 && !dns->snddq.empty () && in_seq) 948 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
949 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
899 { 950 {
951 dns->repseq = seqno;
952
953 while (dlen > 1 && !dns->snddq.empty ())
954 {
900 int txtlen = dlen <= 255 ? dlen - 1 : 255; 955 int txtlen = dlen <= 255 ? dlen - 1 : 255;
901 956
902 if (txtlen > dns->snddq.size ()) 957 if (txtlen > dns->snddq.size ())
903 txtlen = dns->snddq.size (); 958 txtlen = dns->snddq.size ();
904 959
905 pkt[offs++] = txtlen; 960 pkt[offs++] = txtlen;
906 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 961 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
907 offs += txtlen; 962 offs += txtlen;
908 dns->snddq.remove (txtlen); 963 dns->snddq.remove (txtlen);
909 964
910 dlen -= txtlen + 1; 965 dlen -= txtlen + 1;
966 }
911 } 967 }
912 968
913 // avoid empty TXT rdata 969 // avoid completely empty TXT rdata
914 if (offs == rdlen_offs) 970 if (offs == rdlen_offs)
915 pkt[offs++] = 0; 971 pkt[offs++] = 0;
916 972
917 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 973 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
918 } 974 }
… …
954 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1010 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
955 pkt [offs++] = 0; pkt [offs++] = 0; 1011 pkt [offs++] = 0; pkt [offs++] = 0;
956 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1012 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
957 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1013 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
958 1014
959 slog (L_INFO, _("DNS: client %d tries to connect"), client); 1015 slog (L_INFO, _("DNS: client %d connects"), client);
960 1016
961 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1017 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
962 pkt [offs++] = CMD_IP_REJ; 1018 pkt [offs++] = CMD_IP_REJ;
963 1019
964 if (0 < client && client <= conns.size ()) 1020 if (0 < client && client <= conns.size ())
… …
998 { 1054 {
999 dns_connection *dns = (*i)->dns; 1055 dns_connection *dns = (*i)->dns;
1000 connection *c = dns->c; 1056 connection *c = dns->c;
1001 int seqno = (*i)->seqno; 1057 int seqno = (*i)->seqno;
1002 u8 data[MAXSIZE], *datap = data; 1058 u8 data[MAXSIZE], *datap = data;
1059 //printf ("rcv pkt %x\n", seqno);//D
1003 1060
1004 if ((*i)->retry) 1061 if ((*i)->retry)
1005 { 1062 {
1006 dns->send_interval *= 1.01; 1063 dns->send_interval *= 1.01;
1007 if (dns->send_interval > MAX_SEND_INTERVAL) 1064 if (dns->send_interval > MAX_SEND_INTERVAL)
1008 dns->send_interval = MAX_SEND_INTERVAL; 1065 dns->send_interval = MAX_SEND_INTERVAL;
1009 } 1066 }
1010 else 1067 else
1011 { 1068 {
1012#if 1 1069#if 0
1013 dns->send_interval *= 0.999; 1070 dns->send_interval *= 0.999;
1014#endif 1071#endif
1015 if (dns->send_interval < MIN_SEND_INTERVAL)
1016 dns->send_interval = MIN_SEND_INTERVAL;
1017
1018 // the latency surely puts an upper bound on 1072 // the latency surely puts an upper bound on
1019 // the minimum send interval 1073 // the minimum send interval
1020 double latency = NOW - (*i)->sent; 1074 double latency = ev_now () - (*i)->sent;
1075
1076 if (latency < dns->min_latency)
1021 dns->last_latency = latency; 1077 dns->min_latency = latency;
1022 1078
1023 if (dns->send_interval > latency) 1079 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1080 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1081
1082 if (dns->send_interval < conf.dns_send_interval)
1024 dns->send_interval = latency; 1083 dns->send_interval = conf.dns_send_interval;
1025 } 1084 }
1026 1085
1027 delete *i; 1086 delete *i;
1028 dns_sndpq.erase (i); 1087 dns_sndpq.erase (i);
1029 1088
… …
1085 1144
1086 if (ip [3] == CMD_IP_RST) 1145 if (ip [3] == CMD_IP_RST)
1087 { 1146 {
1088 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1147 slog (L_DEBUG, _("DNS: got tunnel RST request"));
1089 1148
1090 delete dns; c->dns = 0; 1149 c->dnsv4_reset_connection ();
1091
1092 return;
1093 } 1150 }
1094 else if (ip [3] == CMD_IP_SYN) 1151 else if (ip [3] == CMD_IP_SYN)
1095 { 1152 {
1096 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1153 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1097 dns->established = true; 1154 dns->established = true;
1098 } 1155 }
1099 else if (ip [3] == CMD_IP_REJ) 1156 else if (ip [3] == CMD_IP_REJ)
1100 {
1101 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1157 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1102 abort ();
1103 }
1104 else 1158 else
1105 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1159 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1106 } 1160 }
1107 else 1161 else
1108 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1162 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
… …
1134 break; 1188 break;
1135 } 1189 }
1136} 1190}
1137 1191
1138void 1192void
1139vpn::dnsv4_ev (io_watcher &w, short revents) 1193vpn::dnsv4_ev (ev::io &w, int revents)
1140{ 1194{
1141 if (revents & EVENT_READ) 1195 if (revents & EV_READ)
1142 { 1196 {
1143 dns_packet *pkt = new dns_packet; 1197 dns_packet *pkt = new dns_packet;
1144 struct sockaddr_in sa; 1198 struct sockaddr_in sa;
1145 socklen_t sa_len = sizeof (sa); 1199 socklen_t sa_len = sizeof (sa);
1146 1200
1147 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1201 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1148 1202
1149 if (pkt->len > 0) 1203 if (pkt->len > 0)
1150 { 1204 {
1151 if (THISNODE->dns_port) 1205 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1206 dnsv4_client (*pkt);
1207 else
1152 { 1208 {
1153 dnsv4_server (*pkt); 1209 dnsv4_server (*pkt);
1154 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1210 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1155 } 1211 }
1156 else
1157 dnsv4_client (*pkt);
1158 1212
1159 delete pkt; 1213 delete pkt;
1160 } 1214 }
1161 } 1215 }
1162} 1216}
1163 1217
1164bool 1218bool
1165vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1219vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1166{ 1220{
1167 int client = ntohs (si.port); 1221 int client = ntohl (si.host);
1168 1222
1169 assert (0 < client && client <= conns.size ()); 1223 assert (0 < client && client <= conns.size ());
1170 1224
1171 connection *c = conns [client - 1]; 1225 connection *c = conns [client - 1];
1172 1226
1173 if (!c->dns) 1227 if (!c->dns)
1174 c->dns = new dns_connection (c); 1228 c->dns = new dns_connection (c);
1175 1229
1176 if (!c->dns->snddq.put (pkt)) 1230 if (c->dns->snddq.put (pkt))
1177 return false;
1178
1179 c->dns->tw.trigger (); 1231 c->dns->tw ();
1180 1232
1233 // always return true even if the buffer overflows
1181 return true; 1234 return true;
1182} 1235}
1183 1236
1184void 1237void
1185connection::dnsv4_reset_connection () 1238connection::dnsv4_reset_connection ()
… …
1188} 1241}
1189 1242
1190#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1243#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1191 1244
1192void 1245void
1193dns_connection::time_cb (time_watcher &w) 1246dns_connection::time_cb (ev::timer &w, int revents)
1194{ 1247{
1195 // servers have to be polled 1248 // servers have to be polled
1196 if (THISNODE->dns_port) 1249 if (THISNODE->dns_port)
1197 return; 1250 return;
1198 1251
1199 // check for timeouts and (re)transmit 1252 // check for timeouts and (re)transmit
1200 tstamp next = NOW + poll_interval; 1253 tstamp next = ev::now () + poll_interval;
1201 dns_snd *send = 0; 1254 dns_snd *send = 0;
1202 1255
1203 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1256 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1204 i != vpn->dns_sndpq.end (); 1257 i != vpn->dns_sndpq.end ();
1205 ++i) 1258 ++i)
1206 { 1259 {
1207 dns_snd *r = *i; 1260 dns_snd *r = *i;
1208 1261
1209 if (r->timeout <= NOW) 1262 if (r->timeout <= ev_now ())
1210 { 1263 {
1211 if (!send) 1264 if (!send)
1212 { 1265 {
1213 send = r; 1266 send = r;
1214 1267
1215 r->retry++; 1268 r->retry++;
1216 r->timeout = NOW + (r->retry * last_latency * 8.); 1269 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1270 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1217 1271
1218 // the following code changes the query section a bit, forcing 1272 // the following code changes the query section a bit, forcing
1219 // the forwarder to generate a new request 1273 // the forwarder to generate a new request
1220 if (r->stdhdr) 1274 if (r->stdhdr)
1221 {
1222 //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);
1223 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1275 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1224 }
1225 } 1276 }
1226 } 1277 }
1227 else 1278 else
1228 NEXT (r->timeout); 1279 NEXT (r->timeout);
1229 } 1280 }
1230 1281
1231 if (last_sent + send_interval <= NOW)
1232 {
1233 if (!send) 1282 if (!send)
1283 {
1284 // generate a new packet, if wise
1285
1286 if (!established)
1234 { 1287 {
1235 // generate a new packet, if wise 1288 if (vpn->dns_sndpq.empty ())
1236
1237 if (!established)
1238 { 1289 {
1239 if (vpn->dns_sndpq.empty ())
1240 {
1241 send = new dns_snd (this); 1290 send = new dns_snd (this);
1242 1291
1243 printf ("new conn %p %d\n", this, c->conf->id);//D
1244 cfg.reset (THISNODE->id); 1292 cfg.reset (THISNODE->id);
1245 send->gen_syn_req (); 1293 send->gen_syn_req ();
1246 }
1247 } 1294 }
1248 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1295 }
1296 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1249 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1297 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1298 {
1299 if (last_sent + send_interval <= ev_now ())
1250 { 1300 {
1251 //printf ("sending data request etc.\n"); //D 1301 //printf ("sending data request etc.\n"); //D
1252 if (!snddq.empty ()) 1302 if (!snddq.empty () || last_received + 1. > ev_now ())
1253 { 1303 {
1254 poll_interval = send_interval; 1304 poll_interval = send_interval;
1255 NEXT (NOW + send_interval); 1305 NEXT (ev_now () + send_interval);
1256 } 1306 }
1257 1307
1258 send = new dns_snd (this); 1308 send = new dns_snd (this);
1259 send->gen_stream_req (sndseq, snddq); 1309 send->gen_stream_req (sndseq, snddq);
1260 send->timeout = NOW + last_latency * 8.; 1310 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1311 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1261 1312
1262 sndseq = (sndseq + 1) & SEQNO_MASK; 1313 sndseq = (sndseq + 1) & SEQNO_MASK;
1263 } 1314 }
1264 1315 else
1265 if (send) 1316 NEXT (last_sent + send_interval);
1266 vpn->dns_sndpq.push_back (send);
1267 } 1317 }
1268 1318
1269 if (send) 1319 if (send)
1270 { 1320 vpn->dns_sndpq.push_back (send);
1271 last_sent = NOW; 1321 }
1322
1323 if (send)
1324 {
1325 last_sent = ev_now ();
1272 sendto (vpn->dnsv4_fd, 1326 sendto (vpn->dnsv4_fd,
1273 send->pkt->at (0), send->pkt->len, 0, 1327 send->pkt->at (0), send->pkt->len, 0,
1274 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1328 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1275 }
1276 } 1329 }
1277 else
1278 NEXT (last_sent + send_interval);
1279 1330
1280 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1331 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1281 poll_interval, send_interval, next - NOW, 1332 poll_interval, send_interval, next - ev_now (),
1282 vpn->dns_sndpq.size (), snddq.size ()); 1333 vpn->dns_sndpq.size (), snddq.size (),
1334 rcvpq.size ());
1283 1335
1284 // TODO: no idea when this happens, but when next < NOW, we have a problem 1336 // TODO: no idea when this happens, but when next < ev_now (), we have a problem
1337 // doesn't seem to happen anymore
1285 if (next < NOW + 0.0001) 1338 if (next < ev_now () + 0.001)
1286 next = NOW + 0.1; 1339 next = ev_now () + 0.1;
1287 1340
1288 w.start (next); 1341 w.start (next - ev_now ());
1289} 1342}
1290 1343
1291#endif 1344#endif
1292 1345

Diff Legend

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