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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.21 by pcg, Sun Mar 6 21:33:40 2005 UTC vs.
Revision 1.49 by root, Tue Feb 8 23:11:36 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
… …
155 enc_len [len] = n; 168 enc_len [len] = n;
156 dec_len [n] = len; 169 dec_len [n] = len;
157 } 170 }
158} 171}
159 172
173unsigned int
160unsigned int basecoder::encode_len (unsigned int len) 174basecoder::encode_len (unsigned int len)
161{ 175{
162 return enc_len [len]; 176 return enc_len [len];
163} 177}
164 178
179unsigned int
165unsigned int basecoder::decode_len (unsigned int len) 180basecoder::decode_len (unsigned int len)
166{ 181{
167 while (len && !dec_len [len]) 182 while (len && !dec_len [len])
168 --len; 183 --len;
169 184
170 return dec_len [len]; 185 return dec_len [len];
171} 186}
172 187
188unsigned int
173unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 189basecoder::encode (char *dst, u8 *src, unsigned int len)
174{ 190{
175 if (!len || len > MAX_DEC_LEN) 191 if (!len || len > MAX_DEC_LEN)
176 return 0; 192 return 0;
177 193
178 int elen = encode_len (len); 194 int elen = encode_len (len);
… …
197 *dst++ = cmap.encode [dst_ [i]]; 213 *dst++ = cmap.encode [dst_ [i]];
198 214
199 return elen; 215 return elen;
200} 216}
201 217
218unsigned int
202unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 219basecoder::decode (u8 *dst, char *src, unsigned int len)
203{ 220{
204 if (!len || len > MAX_ENC_LEN) 221 if (!len || len > MAX_ENC_LEN)
205 return 0; 222 return 0;
206 223
207 u8 src_ [MAX_ENC_LEN]; 224 u8 src_ [MAX_ENC_LEN];
… …
265static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 282static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
266 283
267///////////////////////////////////////////////////////////////////////////// 284/////////////////////////////////////////////////////////////////////////////
268 285
269#define HDRSIZE 6 286#define HDRSIZE 6
270 287
288inline void
271inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 289encode_header (char *data, int clientid, int seqno, int retry = 0)
272{ 290{
273 seqno &= SEQNO_MASK; 291 seqno &= SEQNO_MASK;
274 292
275 u8 hdr[3] = { 293 u8 hdr[3] = {
276 clientid, 294 clientid,
… …
281 assert (clientid < 256); 299 assert (clientid < 256);
282 300
283 cdc26.encode (data, hdr, 3); 301 cdc26.encode (data, hdr, 3);
284} 302}
285 303
304inline void
286inline void decode_header (char *data, int &clientid, int &seqno) 305decode_header (char *data, int &clientid, int &seqno)
287{ 306{
288 u8 hdr[3]; 307 u8 hdr[3];
289 308
290 cdc26.decode (hdr, data, HDRSIZE); 309 cdc26.decode (hdr, data, HDRSIZE);
291 310
… …
324byte_stream::~byte_stream () 343byte_stream::~byte_stream ()
325{ 344{
326 delete data; 345 delete data;
327} 346}
328 347
348void
329void byte_stream::remove (int count) 349byte_stream::remove (int count)
330{ 350{
331 if (count > fill) 351 if (count > fill)
332 assert (count <= fill); 352 assert (count <= fill);
333 353
334 memmove (data, data + count, fill -= count); 354 memmove (data, data + count, fill -= count);
335} 355}
336 356
357bool
337bool byte_stream::put (u8 *data, unsigned int datalen) 358byte_stream::put (u8 *data, unsigned int datalen)
338{ 359{
339 if (maxsize - fill < datalen) 360 if (maxsize - fill < datalen)
340 return false; 361 return false;
341 362
342 memcpy (this->data + fill, data, datalen); fill += datalen; 363 memcpy (this->data + fill, data, datalen); fill += datalen;
343 364
344 return true; 365 return true;
345} 366}
346 367
368bool
347bool byte_stream::put (vpn_packet *pkt) 369byte_stream::put (vpn_packet *pkt)
348{ 370{
349 if (maxsize - fill < pkt->len + 2) 371 if (maxsize - fill < pkt->len + 2)
350 return false; 372 return false;
351 373
352 data [fill++] = pkt->len >> 8; 374 data [fill++] = pkt->len >> 8;
… …
409struct dns_cfg 431struct dns_cfg
410{ 432{
411 static int next_uid; 433 static int next_uid;
412 434
413 u8 id1, id2, id3, id4; 435 u8 id1, id2, id3, id4;
436
414 u8 version; 437 u8 version;
438 u8 flags;
415 u8 rrtype; 439 u8 rrtype;
416 u8 flags;
417 u8 def_ttl; 440 u8 def_ttl;
418 u8 rcv_cdc; 441
419 u8 snd_cdc;
420 u16 max_size;
421 u16 client; 442 u16 client;
422 u16 uid; // to make request unique 443 u16 uid; // to make request unique
423 444
424 u8 reserved[8]; 445 u16 max_size;
446 u8 seq_cdc;
447 u8 req_cdc;
448
449 u8 rep_cdc;
450 u8 delay; // time in 0.01s units that the server may delay replying packets
451 u8 r3, r4;
452
453 u8 r5, r6, r7, r8;
425 454
426 void reset (int clientid); 455 void reset (int clientid);
427 bool valid (); 456 bool valid ();
428}; 457};
429 458
430int dns_cfg::next_uid; 459int dns_cfg::next_uid;
431 460
461void
432void dns_cfg::reset (int clientid) 462dns_cfg::reset (int clientid)
433{ 463{
434 id1 = 'G'; 464 id1 = 'G';
435 id2 = 'V'; 465 id2 = 'V';
436 id3 = 'P'; 466 id3 = 'P';
437 id4 = 'E'; 467 id4 = 'E';
438 468
439 version = 1; 469 version = 1;
440 470
441 rrtype = RR_TYPE_TXT; 471 rrtype = RR_TYPE_TXT;
442 flags = 0; 472 flags = 0;
443 def_ttl = 1; 473 def_ttl = 0;
474 seq_cdc = 26;
475 req_cdc = 62;
444 rcv_cdc = 0; 476 rep_cdc = 0;
445 snd_cdc = 62;
446 max_size = ntohs (MAX_PKT_SIZE); 477 max_size = htons (MAX_PKT_SIZE);
447 client = ntohs (clientid); 478 client = htons (clientid);
448 uid = next_uid++; 479 uid = next_uid++;
480 delay = 0;
449 481
450 memset (reserved, 0, 8); 482 r3 = r4 = 0;
483 r4 = r5 = r6 = r7 = 0;
451} 484}
452 485
486bool
453bool dns_cfg::valid () 487dns_cfg::valid ()
454{ 488{
489 // although the protocol itself allows for some configurability,
490 // only the following encoding/decoding settings are implemented.
455 return id1 == 'G' 491 return id1 == 'G'
456 && id2 == 'V' 492 && id2 == 'V'
457 && id3 == 'P' 493 && id3 == 'P'
458 && id4 == 'E' 494 && id4 == 'E'
495 && seq_cdc == 26
496 && req_cdc == 62
497 && rep_cdc == 0
459 && version == 1 498 && version == 1;
460 && flags == 0
461 && rcv_cdc == 0
462 && snd_cdc == 62
463 && max_size == ntohs (MAX_PKT_SIZE);
464} 499}
465 500
466struct dns_packet : net_packet 501struct dns_packet : net_packet
467{ 502{
468 u16 id; 503 u16 id;
469 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 504 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
470 u16 qdcount, ancount, nscount, arcount; 505 u16 qdcount, ancount, nscount, arcount;
471 506
472 u8 data[MAXSIZE - 6 * 2]; 507 u8 data [MAXSIZE - 6 * 2];
473 508
474 int decode_label (char *data, int size, int &offs); 509 int decode_label (char *data, int size, int &offs);
475}; 510};
476 511
512int
477int dns_packet::decode_label (char *data, int size, int &offs) 513dns_packet::decode_label (char *data, int size, int &offs)
478{ 514{
479 char *orig = data; 515 char *orig = data;
480 516
481 memset (data, 0, size); 517 memset (data, 0, size);
482 518
… …
508 return data - orig; 544 return data - orig;
509} 545}
510 546
511///////////////////////////////////////////////////////////////////////////// 547/////////////////////////////////////////////////////////////////////////////
512 548
549static
550u16 next_id ()
551{
513static u16 dns_id = 0; // TODO: should be per-vpn 552 static u16 dns_id = 0; // TODO: should be per-vpn
514 553
515static u16 next_id ()
516{
517 if (!dns_id) 554 if (!dns_id)
518 dns_id = time (0); 555 dns_id = time (0);
519 556
520 // the simplest lsfr with periodicity 65535 i could find 557 // the simplest lsfr with periodicity 65535 i could find
521 dns_id = (dns_id << 1) 558 dns_id = (dns_id << 1)
… …
539 576
540 bool established; 577 bool established;
541 578
542 tstamp last_received; 579 tstamp last_received;
543 tstamp last_sent; 580 tstamp last_sent;
544 double last_latency; 581 double min_latency;
545 double poll_interval, send_interval; 582 double poll_interval, send_interval;
546 583
547 vector<dns_rcv *> rcvpq; 584 vector<dns_rcv *> rcvpq;
548 585
549 byte_stream rcvdq; int rcvseq; 586 byte_stream rcvdq; int rcvseq; int repseq;
550 byte_stream snddq; int sndseq; 587 byte_stream snddq; int sndseq;
551 588
552 void time_cb (time_watcher &w); time_watcher tw; 589 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
553 void receive_rep (dns_rcv *r); 590 void receive_rep (dns_rcv *r);
554 591
555 dns_connection (connection *c); 592 dns_connection (connection *c);
556 ~dns_connection (); 593 ~dns_connection ();
557}; 594};
… …
576: dns (dns) 613: dns (dns)
577{ 614{
578 timeout = 0; 615 timeout = 0;
579 retry = 0; 616 retry = 0;
580 seqno = 0; 617 seqno = 0;
581 sent = NOW; 618 sent = ev_now ();
582 stdhdr = false; 619 stdhdr = false;
583 620
584 pkt = new dns_packet; 621 pkt = new dns_packet;
585 622
586 pkt->id = next_id (); 623 pkt->id = next_id ();
… …
589dns_snd::~dns_snd () 626dns_snd::~dns_snd ()
590{ 627{
591 delete pkt; 628 delete pkt;
592} 629}
593 630
631static void
594static void append_domain (dns_packet &pkt, int &offs, const char *domain) 632append_domain (dns_packet &pkt, int &offs, const char *domain)
595{ 633{
596 // add tunnel domain 634 // add tunnel domain
597 for (;;) 635 for (;;)
598 { 636 {
599 const char *end = strchr (domain, '.'); 637 const char *end = strchr (domain, '.');
… …
612 650
613 domain = end + 1; 651 domain = end + 1;
614 } 652 }
615} 653}
616 654
655void
617void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 656dns_snd::gen_stream_req (int seqno, byte_stream &stream)
618{ 657{
619 stdhdr = true; 658 stdhdr = true;
620 this->seqno = seqno; 659 this->seqno = seqno;
621 660
622 timeout = NOW + INITIAL_TIMEOUT; 661 timeout = ev_now () + INITIAL_TIMEOUT;
623 662
624 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 663 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
625 pkt->qdcount = htons (1); 664 pkt->qdcount = htons (1);
626 665
627 int offs = 6*2; 666 int offs = 6*2;
… …
660 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 699 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
661 700
662 pkt->len = offs; 701 pkt->len = offs;
663} 702}
664 703
704void
665void dns_snd::gen_syn_req () 705dns_snd::gen_syn_req ()
666{ 706{
667 timeout = NOW + INITIAL_SYN_TIMEOUT; 707 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
668
669 printf ("send syn\n");//D
670 708
671 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 709 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
672 pkt->qdcount = htons (1); 710 pkt->qdcount = htons (1);
673 711
674 int offs = 6 * 2; 712 int offs = 6 * 2;
… …
713///////////////////////////////////////////////////////////////////////////// 751/////////////////////////////////////////////////////////////////////////////
714 752
715dns_connection::dns_connection (connection *c) 753dns_connection::dns_connection (connection *c)
716: c (c) 754: c (c)
717, rcvdq (MAX_BACKLOG * 2) 755, rcvdq (MAX_BACKLOG * 2)
718, snddq (MAX_BACKLOG * 2) 756, snddq (MAX_BACKLOG)
719, tw (this, &dns_connection::time_cb)
720{ 757{
758 tw.set<dns_connection, &dns_connection::time_cb> (this);
759
721 vpn = c->vpn; 760 vpn = c->vpn;
722 761
723 established = false; 762 established = false;
724 763
725 rcvseq = sndseq = 0; 764 rcvseq = repseq = sndseq = 0;
726 765
727 last_sent = last_received = 0; 766 last_sent = last_received = 0;
728 poll_interval = MIN_POLL_INTERVAL; 767 poll_interval = 0.5; // starting here
729 send_interval = 0.5; // starting rate 768 send_interval = 0.5; // starting rate
730 last_latency = INITIAL_TIMEOUT; 769 min_latency = INITIAL_TIMEOUT;
731} 770}
732 771
733dns_connection::~dns_connection () 772dns_connection::~dns_connection ()
734{ 773{
735 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 774 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
736 i != rcvpq.end (); 775 i != rcvpq.end ();
737 ++i) 776 ++i)
738 delete *i; 777 delete *i;
739} 778}
740 779
780void
741void dns_connection::receive_rep (dns_rcv *r) 781dns_connection::receive_rep (dns_rcv *r)
742{ 782{
743 if (r->datalen) 783 if (r->datalen)
744 { 784 {
745 last_received = NOW; 785 last_received = ev_now ();
746 tw.trigger (); 786 tw ();
747 787
748 poll_interval = send_interval; 788 poll_interval = send_interval;
749 } 789 }
750 else 790 else
751 { 791 {
752 poll_interval *= 1.5; 792 poll_interval *= 1.5;
793
753 if (poll_interval > MAX_POLL_INTERVAL) 794 if (poll_interval > MAX_POLL_INTERVAL)
754 poll_interval = MAX_POLL_INTERVAL; 795 poll_interval = MAX_POLL_INTERVAL;
755 } 796 }
756 797
757 rcvpq.push_back (r); 798 rcvpq.push_back (r);
… …
760 801
761 // find next packet 802 // find next packet
762 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 803 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
763 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 804 if (SEQNO_EQ (rcvseq, (*i)->seqno))
764 { 805 {
806 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
765 // enter the packet into our input stream 807 // enter the packet into our input stream
766 r = *i; 808 r = *i;
767 809
768 // remove the oldest packet, look forward, as it's oldest first 810 // remove the oldest packet, look forward, as it's oldest first
769 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 811 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
770 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 812 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
771 { 813 {
814 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
772 delete *j; 815 delete *j;
773 rcvpq.erase (j); 816 rcvpq.erase (j);
774 break; 817 break;
775 } 818 }
776 819
… …
783 } 826 }
784 827
785 while (vpn_packet *pkt = rcvdq.get ()) 828 while (vpn_packet *pkt = rcvdq.get ())
786 { 829 {
787 sockinfo si; 830 sockinfo si;
788 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 831 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
789 832
790 vpn->recv_vpn_packet (pkt, si); 833 vpn->recv_vpn_packet (pkt, si);
791 834
792 delete pkt; 835 delete pkt;
793 } 836 }
… …
807 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 850 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
808 851
809 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 852 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
810 && pkt.qdcount == htons (1)) 853 && pkt.qdcount == htons (1))
811 { 854 {
812 char qname[MAXSIZE]; 855 char qname [MAXSIZE];
813 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 856 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
814 857
815 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 858 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
816 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 859 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
817 860
… …
824 867
825 int dlen = strlen (THISNODE->domain); 868 int dlen = strlen (THISNODE->domain);
826 869
827 if (qclass == RR_CLASS_IN 870 if (qclass == RR_CLASS_IN
828 && qlen > dlen + 1 871 && qlen > dlen + 1
829 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 872 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
830 { 873 {
831 // now generate reply 874 // now generate reply
832 pkt.ancount = htons (1); // one answer RR 875 pkt.ancount = htons (1); // one answer RR
833 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 876 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
834 877
… …
847 if (0 < client && client <= conns.size ()) 890 if (0 < client && client <= conns.size ())
848 { 891 {
849 connection *c = conns [client - 1]; 892 connection *c = conns [client - 1];
850 dns_connection *dns = c->dns; 893 dns_connection *dns = c->dns;
851 dns_rcv *rcv; 894 dns_rcv *rcv;
852 bool in_seq;
853 895
854 if (dns) 896 if (dns)
855 { 897 {
856 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 898 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
857 if (SEQNO_EQ ((*i)->seqno, seqno)) 899 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
868 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 910 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
869 911
870 goto duplicate_request; 912 goto duplicate_request;
871 } 913 }
872 914
873 in_seq = dns->rcvseq == seqno;
874
875 // new packet, queue 915 // new packet, queue
876 rcv = new dns_rcv (seqno, data, datalen); 916 rcv = new dns_rcv (seqno, data, datalen);
877 dns->receive_rep (rcv); 917 dns->receive_rep (rcv);
878 } 918 }
879 919
… …
886 pkt [offs++] = 0; pkt [offs++] = 0; 926 pkt [offs++] = 0; pkt [offs++] = 0;
887 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 927 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
888 928
889 int rdlen_offs = offs += 2; 929 int rdlen_offs = offs += 2;
890 930
891 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
892 // bind doesn't compress well, so reduce further by one label length
893 dlen -= qlen;
894
895 if (dns) 931 if (dns)
896 { 932 {
933 int dlen = ntohs (dns->cfg.max_size) - offs;
934
935 // bind doesn't compress well, so reduce further by one label length
936 dlen -= qlen;
937
897 // only put data into in-order sequence packets, if 938 // only put data into in-order sequence packets, if
898 // we receive out-of-order packets we generate empty 939 // we receive out-of-order packets we generate empty
899 // replies 940 // replies
900 while (dlen > 1 && !dns->snddq.empty () && in_seq) 941 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
942 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
901 { 943 {
944 dns->repseq = seqno;
945
946 while (dlen > 1 && !dns->snddq.empty ())
947 {
902 int txtlen = dlen <= 255 ? dlen - 1 : 255; 948 int txtlen = dlen <= 255 ? dlen - 1 : 255;
903 949
904 if (txtlen > dns->snddq.size ()) 950 if (txtlen > dns->snddq.size ())
905 txtlen = dns->snddq.size (); 951 txtlen = dns->snddq.size ();
906 952
907 pkt[offs++] = txtlen; 953 pkt[offs++] = txtlen;
908 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 954 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
909 offs += txtlen; 955 offs += txtlen;
910 dns->snddq.remove (txtlen); 956 dns->snddq.remove (txtlen);
911 957
912 dlen -= txtlen + 1; 958 dlen -= txtlen + 1;
959 }
913 } 960 }
914 961
915 // avoid empty TXT rdata 962 // avoid completely empty TXT rdata
916 if (offs == rdlen_offs) 963 if (offs == rdlen_offs)
917 pkt[offs++] = 0; 964 pkt[offs++] = 0;
918 965
919 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 966 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
920 } 967 }
… …
956 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1003 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
957 pkt [offs++] = 0; pkt [offs++] = 0; 1004 pkt [offs++] = 0; pkt [offs++] = 0;
958 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1005 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
959 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1006 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
960 1007
961 slog (L_INFO, _("DNS: client %d tries to connect"), client); 1008 slog (L_INFO, _("DNS: client %d connects"), client);
962 1009
963 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1010 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
964 pkt [offs++] = CMD_IP_REJ; 1011 pkt [offs++] = CMD_IP_REJ;
965 1012
966 if (0 < client && client <= conns.size ()) 1013 if (0 < client && client <= conns.size ())
… …
1000 { 1047 {
1001 dns_connection *dns = (*i)->dns; 1048 dns_connection *dns = (*i)->dns;
1002 connection *c = dns->c; 1049 connection *c = dns->c;
1003 int seqno = (*i)->seqno; 1050 int seqno = (*i)->seqno;
1004 u8 data[MAXSIZE], *datap = data; 1051 u8 data[MAXSIZE], *datap = data;
1052 //printf ("rcv pkt %x\n", seqno);//D
1005 1053
1006 if ((*i)->retry) 1054 if ((*i)->retry)
1007 { 1055 {
1008 dns->send_interval *= 1.01; 1056 dns->send_interval *= 1.01;
1009 if (dns->send_interval > MAX_SEND_INTERVAL) 1057 if (dns->send_interval > MAX_SEND_INTERVAL)
1010 dns->send_interval = MAX_SEND_INTERVAL; 1058 dns->send_interval = MAX_SEND_INTERVAL;
1011 } 1059 }
1012 else 1060 else
1013 { 1061 {
1014#if 1 1062#if 0
1015 dns->send_interval *= 0.999; 1063 dns->send_interval *= 0.999;
1016#endif 1064#endif
1017 if (dns->send_interval < MIN_SEND_INTERVAL)
1018 dns->send_interval = MIN_SEND_INTERVAL;
1019
1020 // the latency surely puts an upper bound on 1065 // the latency surely puts an upper bound on
1021 // the minimum send interval 1066 // the minimum send interval
1022 double latency = NOW - (*i)->sent; 1067 double latency = ev_now () - (*i)->sent;
1068
1069 if (latency < dns->min_latency)
1023 dns->last_latency = latency; 1070 dns->min_latency = latency;
1024 1071
1025 if (dns->send_interval > latency) 1072 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1073 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1074
1075 if (dns->send_interval < conf.dns_send_interval)
1026 dns->send_interval = latency; 1076 dns->send_interval = conf.dns_send_interval;
1027 } 1077 }
1028 1078
1029 delete *i; 1079 delete *i;
1030 dns_sndpq.erase (i); 1080 dns_sndpq.erase (i);
1031 1081
… …
1136 break; 1186 break;
1137 } 1187 }
1138} 1188}
1139 1189
1140void 1190void
1141vpn::dnsv4_ev (io_watcher &w, short revents) 1191vpn::dnsv4_ev (ev::io &w, int revents)
1142{ 1192{
1143 if (revents & EVENT_READ) 1193 if (revents & EV_READ)
1144 { 1194 {
1145 dns_packet *pkt = new dns_packet; 1195 dns_packet *pkt = new dns_packet;
1146 struct sockaddr_in sa; 1196 struct sockaddr_in sa;
1147 socklen_t sa_len = sizeof (sa); 1197 socklen_t sa_len = sizeof (sa);
1148 1198
1149 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1199 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1150 1200
1151 if (pkt->len > 0) 1201 if (pkt->len > 0)
1152 { 1202 {
1153 if (THISNODE->dns_port) 1203 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1204 dnsv4_client (*pkt);
1205 else
1154 { 1206 {
1155 dnsv4_server (*pkt); 1207 dnsv4_server (*pkt);
1156 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1208 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1157 } 1209 }
1158 else
1159 dnsv4_client (*pkt);
1160 1210
1161 delete pkt; 1211 delete pkt;
1162 } 1212 }
1163 } 1213 }
1164} 1214}
1165 1215
1166bool 1216bool
1167vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1217vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1168{ 1218{
1169 int client = ntohs (si.port); 1219 int client = ntohl (si.host);
1170 1220
1171 assert (0 < client && client <= conns.size ()); 1221 assert (0 < client && client <= conns.size ());
1172 1222
1173 connection *c = conns [client - 1]; 1223 connection *c = conns [client - 1];
1174 1224
1175 if (!c->dns) 1225 if (!c->dns)
1176 c->dns = new dns_connection (c); 1226 c->dns = new dns_connection (c);
1177 1227
1178 if (!c->dns->snddq.put (pkt)) 1228 if (c->dns->snddq.put (pkt))
1179 return false;
1180
1181 c->dns->tw.trigger (); 1229 c->dns->tw ();
1182 1230
1231 // always return true even if the buffer overflows
1183 return true; 1232 return true;
1184} 1233}
1185 1234
1186void 1235void
1187connection::dnsv4_reset_connection () 1236connection::dnsv4_reset_connection ()
… …
1190} 1239}
1191 1240
1192#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1241#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1193 1242
1194void 1243void
1195dns_connection::time_cb (time_watcher &w) 1244dns_connection::time_cb (ev::timer &w, int revents)
1196{ 1245{
1197 // servers have to be polled 1246 // servers have to be polled
1198 if (THISNODE->dns_port) 1247 if (THISNODE->dns_port)
1199 return; 1248 return;
1200 1249
1201 // check for timeouts and (re)transmit 1250 // check for timeouts and (re)transmit
1202 tstamp next = NOW + poll_interval; 1251 tstamp next = ev::now () + poll_interval;
1203 dns_snd *send = 0; 1252 dns_snd *send = 0;
1204 1253
1205 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1254 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1206 i != vpn->dns_sndpq.end (); 1255 i != vpn->dns_sndpq.end ();
1207 ++i) 1256 ++i)
1208 { 1257 {
1209 dns_snd *r = *i; 1258 dns_snd *r = *i;
1210 1259
1211 if (r->timeout <= NOW) 1260 if (r->timeout <= ev_now ())
1212 { 1261 {
1213 if (!send) 1262 if (!send)
1214 { 1263 {
1215 send = r; 1264 send = r;
1216 1265
1217 r->retry++; 1266 r->retry++;
1218 r->timeout = NOW + (r->retry * last_latency * 8.); 1267 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1268 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1219 1269
1220 // the following code changes the query section a bit, forcing 1270 // the following code changes the query section a bit, forcing
1221 // the forwarder to generate a new request 1271 // the forwarder to generate a new request
1222 if (r->stdhdr) 1272 if (r->stdhdr)
1223 {
1224 //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);
1225 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1273 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1226 }
1227 } 1274 }
1228 } 1275 }
1229 else 1276 else
1230 NEXT (r->timeout); 1277 NEXT (r->timeout);
1231 } 1278 }
1232 1279
1233 if (last_sent + send_interval <= NOW)
1234 {
1235 if (!send) 1280 if (!send)
1281 {
1282 // generate a new packet, if wise
1283
1284 if (!established)
1236 { 1285 {
1237 // generate a new packet, if wise 1286 if (vpn->dns_sndpq.empty ())
1238
1239 if (!established)
1240 { 1287 {
1241 if (vpn->dns_sndpq.empty ())
1242 {
1243 send = new dns_snd (this); 1288 send = new dns_snd (this);
1244 1289
1245 printf ("new conn %p %d\n", this, c->conf->id);//D
1246 cfg.reset (THISNODE->id); 1290 cfg.reset (THISNODE->id);
1247 send->gen_syn_req (); 1291 send->gen_syn_req ();
1248 }
1249 } 1292 }
1250 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1293 }
1294 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1251 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1295 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1296 {
1297 if (last_sent + send_interval <= ev_now ())
1252 { 1298 {
1253 //printf ("sending data request etc.\n"); //D 1299 //printf ("sending data request etc.\n"); //D
1254 if (!snddq.empty ()) 1300 if (!snddq.empty () || last_received + 1. > ev_now ())
1255 { 1301 {
1256 poll_interval = send_interval; 1302 poll_interval = send_interval;
1257 NEXT (NOW + send_interval); 1303 NEXT (ev_now () + send_interval);
1258 } 1304 }
1259 1305
1260 send = new dns_snd (this); 1306 send = new dns_snd (this);
1261 send->gen_stream_req (sndseq, snddq); 1307 send->gen_stream_req (sndseq, snddq);
1262 send->timeout = NOW + last_latency * 8.; 1308 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1309 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1263 1310
1264 sndseq = (sndseq + 1) & SEQNO_MASK; 1311 sndseq = (sndseq + 1) & SEQNO_MASK;
1265 } 1312 }
1266 1313 else
1267 if (send) 1314 NEXT (last_sent + send_interval);
1268 vpn->dns_sndpq.push_back (send);
1269 } 1315 }
1270 1316
1271 if (send) 1317 if (send)
1272 { 1318 vpn->dns_sndpq.push_back (send);
1273 last_sent = NOW; 1319 }
1320
1321 if (send)
1322 {
1323 last_sent = ev_now ();
1274 sendto (vpn->dnsv4_fd, 1324 sendto (vpn->dnsv4_fd,
1275 send->pkt->at (0), send->pkt->len, 0, 1325 send->pkt->at (0), send->pkt->len, 0,
1276 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1326 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1277 }
1278 } 1327 }
1279 else
1280 NEXT (last_sent + send_interval);
1281 1328
1282 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1329 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1283 poll_interval, send_interval, next - NOW, 1330 poll_interval, send_interval, next - ev_now (),
1284 vpn->dns_sndpq.size (), snddq.size ()); 1331 vpn->dns_sndpq.size (), snddq.size (),
1332 rcvpq.size ());
1285 1333
1286 // TODO: no idea when this happens, but when next < NOW, we have a problem 1334 // TODO: no idea when this happens, but when next < ev_now (), we have a problem
1335 // doesn't seem to happen anymore
1287 if (next < NOW + 0.0001) 1336 if (next < ev_now () + 0.001)
1288 next = NOW + 0.1; 1337 next = ev_now () + 0.1;
1289 1338
1290 w.start (next); 1339 w.start (next - ev_now ());
1291} 1340}
1292 1341
1293#endif 1342#endif
1294 1343

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