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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.17 by pcg, Sat Mar 5 03:47:05 2005 UTC vs.
Revision 1.40 by pcg, Sat Jul 9 20:29:29 2005 UTC

… …
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details. 15 GNU General 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
18 along with gvpe; if not, write to the Free Software 18 along with gvpe; if not, write to the Free Software
19 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20*/ 20*/
21
22// TODO: EDNS0 option to increase dns mtu?
23// TODO: re-write dns packet parsing/creation using a safe mem-buffer
24// to ensure no buffer overflows or similar problems.
21 25
22#include "config.h" 26#include "config.h"
23 27
24#if ENABLE_DNS 28#if ENABLE_DNS
25 29
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 30// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27// it's a hack, use only in emergency situations please. 31// it's a hack, use only in emergency situations please.
28 32
29#include <cstring> 33#include <cstring>
34#include <cassert>
30 35
31#include <sys/types.h> 36#include <sys/types.h>
32#include <sys/socket.h> 37#include <sys/socket.h>
33#include <sys/wait.h> 38#include <sys/wait.h>
34#include <sys/uio.h> 39#include <sys/uio.h>
… …
43 48
44#include "netcompat.h" 49#include "netcompat.h"
45 50
46#include "vpn.h" 51#include "vpn.h"
47 52
48#define MIN_POLL_INTERVAL .02 // how often to poll minimally when the server has data
49#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data 53#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
50#define ACTIVITY_INTERVAL 5. 54#define ACTIVITY_INTERVAL 5.
51 55
52#define INITIAL_TIMEOUT 0.1 // retry timeouts 56#define INITIAL_TIMEOUT 0.1 // retry timeouts
53#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 57#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54 58
55#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
56#define MAX_SEND_INTERVAL 0.5 // optimistic? 59#define MAX_SEND_INTERVAL 2. // optimistic?
57 60
58#define MAX_OUTSTANDING 10 // max. outstanding requests
59#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 61#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 62#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
61 63
62#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well 64#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 65// 240 leaves about 4 bytes of server reply data
64// every two request bytes less give room for one reply byte 66// every request byte less give room for two reply bytes
65 67
66#define SEQNO_MASK 0x3fff 68#define SEQNO_MASK 0x3fff
67#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 69#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
68 70
69#define MAX_LBL_SIZE 63 71#define MAX_LBL_SIZE 63
… …
264static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 266static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
265 267
266///////////////////////////////////////////////////////////////////////////// 268/////////////////////////////////////////////////////////////////////////////
267 269
268#define HDRSIZE 6 270#define HDRSIZE 6
269 271
270inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 272inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
271{ 273{
272 seqno &= SEQNO_MASK; 274 seqno &= SEQNO_MASK;
273 275
274 u8 hdr[3] = { 276 u8 hdr[3] = {
… …
356 return true; 358 return true;
357} 359}
358 360
359vpn_packet *byte_stream::get () 361vpn_packet *byte_stream::get ()
360{ 362{
363 unsigned int len;
364
365 for (;;)
366 {
361 unsigned int len = (data [0] << 8) | data [1]; 367 len = (data [0] << 8) | data [1];
362 368
363 if (len > MAXSIZE && fill >= 2) 369 if (len <= MAXSIZE || fill < 2)
364 assert (len <= MAXSIZE || fill < 2); // TODO handle this gracefully, connection reset 370 break;
365 371
372 // TODO: handle this better than skipping, e.g. by reset
373 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
374 remove (1);
375 }
376
366 if (fill < len + 2) 377 if (fill < len + 2)
367 return 0; 378 return 0;
368 379
369 vpn_packet *pkt = new vpn_packet; 380 vpn_packet *pkt = new vpn_packet;
370 381
… …
399struct dns_cfg 410struct dns_cfg
400{ 411{
401 static int next_uid; 412 static int next_uid;
402 413
403 u8 id1, id2, id3, id4; 414 u8 id1, id2, id3, id4;
415
404 u8 version; 416 u8 version;
417 u8 flags;
405 u8 rrtype; 418 u8 rrtype;
406 u8 flags;
407 u8 def_ttl; 419 u8 def_ttl;
408 u8 rcv_cdc; 420
409 u8 snd_cdc;
410 u16 max_size;
411 u16 client; 421 u16 client;
412 u16 uid; // to make request unique 422 u16 uid; // to make request unique
413 423
414 u8 reserved[8]; 424 u16 max_size;
425 u8 seq_cdc;
426 u8 req_cdc;
427
428 u8 rep_cdc;
429 u8 delay; // time in 0.01s units that the server may delay replying packets
430 u8 r3, r4;
431
432 u8 r5, r6, r7, r8;
415 433
416 void reset (int clientid); 434 void reset (int clientid);
417 bool valid (); 435 bool valid ();
418}; 436};
419 437
… …
428 446
429 version = 1; 447 version = 1;
430 448
431 rrtype = RR_TYPE_TXT; 449 rrtype = RR_TYPE_TXT;
432 flags = 0; 450 flags = 0;
433 def_ttl = 1; 451 def_ttl = 0;
452 seq_cdc = 26;
453 req_cdc = 62;
434 rcv_cdc = 0; 454 rep_cdc = 0;
435 snd_cdc = 62;
436 max_size = ntohs (MAX_PKT_SIZE); 455 max_size = htons (MAX_PKT_SIZE);
437 client = ntohs (clientid); 456 client = htons (clientid);
438 uid = next_uid++; 457 uid = next_uid++;
458 delay = 0;
439 459
440 memset (reserved, 0, 8); 460 r3 = r4 = 0;
461 r4 = r5 = r6 = r7 = 0;
441} 462}
442 463
443bool dns_cfg::valid () 464bool dns_cfg::valid ()
444{ 465{
466 // although the protocol itself allows for some configurability,
467 // only the following encoding/decoding settings are implemented.
445 return id1 == 'G' 468 return id1 == 'G'
446 && id2 == 'V' 469 && id2 == 'V'
447 && id3 == 'P' 470 && id3 == 'P'
448 && id4 == 'E' 471 && id4 == 'E'
472 && seq_cdc == 26
473 && req_cdc == 62
474 && rep_cdc == 0
449 && version == 1 475 && version == 1;
450 && flags == 0
451 && rcv_cdc == 0
452 && snd_cdc == 62
453 && max_size == ntohs (MAX_PKT_SIZE);
454} 476}
455 477
456struct dns_packet : net_packet 478struct dns_packet : net_packet
457{ 479{
458 u16 id; 480 u16 id;
459 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 481 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
460 u16 qdcount, ancount, nscount, arcount; 482 u16 qdcount, ancount, nscount, arcount;
461 483
462 u8 data[MAXSIZE - 6 * 2]; 484 u8 data [MAXSIZE - 6 * 2];
463 485
464 int decode_label (char *data, int size, int &offs); 486 int decode_label (char *data, int size, int &offs);
465}; 487};
466 488
467int dns_packet::decode_label (char *data, int size, int &offs) 489int dns_packet::decode_label (char *data, int size, int &offs)
… …
498 return data - orig; 520 return data - orig;
499} 521}
500 522
501///////////////////////////////////////////////////////////////////////////// 523/////////////////////////////////////////////////////////////////////////////
502 524
525static u16 dns_id = 0; // TODO: should be per-vpn
526
527static u16 next_id ()
528{
529 if (!dns_id)
530 dns_id = time (0);
531
532 // the simplest lsfr with periodicity 65535 i could find
533 dns_id = (dns_id << 1)
534 | (((dns_id >> 1)
535 ^ (dns_id >> 2)
536 ^ (dns_id >> 4)
537 ^ (dns_id >> 15)) & 1);
538
539 return dns_id;
540}
541
542struct dns_rcv;
543struct dns_snd;
544
545struct dns_connection
546{
547 connection *c;
548 struct vpn *vpn;
549
550 dns_cfg cfg;
551
552 bool established;
553
554 tstamp last_received;
555 tstamp last_sent;
556 double min_latency;
557 double poll_interval, send_interval;
558
559 vector<dns_rcv *> rcvpq;
560
561 byte_stream rcvdq; int rcvseq; int repseq;
562 byte_stream snddq; int sndseq;
563
564 void time_cb (time_watcher &w); time_watcher tw;
565 void receive_rep (dns_rcv *r);
566
567 dns_connection (connection *c);
568 ~dns_connection ();
569};
570
503struct dns_snd 571struct dns_snd
504{ 572{
505 dns_packet *pkt; 573 dns_packet *pkt;
506 tstamp timeout, sent; 574 tstamp timeout, sent;
507 int retry; 575 int retry;
508 struct dns_connection *dns; 576 struct dns_connection *dns;
509 int seqno; 577 int seqno;
510 bool stdhdr; 578 bool stdhdr;
511 579
512 void gen_stream_req (int seqno, byte_stream &stream); 580 void gen_stream_req (int seqno, byte_stream &stream);
513 void gen_syn_req (const dns_cfg &cfg); 581 void gen_syn_req ();
514 582
515 dns_snd (dns_connection *dns); 583 dns_snd (dns_connection *dns);
516 ~dns_snd (); 584 ~dns_snd ();
517}; 585};
518
519static u16 dns_id = 12098; // TODO: should be per-vpn
520
521static u16 next_id ()
522{
523 // the simplest lsfr with periodicity 65535 i could find
524 dns_id = (dns_id << 1)
525 | (((dns_id >> 1)
526 ^ (dns_id >> 2)
527 ^ (dns_id >> 4)
528 ^ (dns_id >> 15)) & 1);
529
530 return dns_id;
531}
532 586
533dns_snd::dns_snd (dns_connection *dns) 587dns_snd::dns_snd (dns_connection *dns)
534: dns (dns) 588: dns (dns)
535{ 589{
536 timeout = 0; 590 timeout = 0;
… …
581 635
582 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 636 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
583 pkt->qdcount = htons (1); 637 pkt->qdcount = htons (1);
584 638
585 int offs = 6*2; 639 int offs = 6*2;
586 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 640 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
587 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 641 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
588 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 642 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
589 643
590 char enc[256], *encp = enc; 644 char enc[256], *encp = enc;
591 encode_header (enc, THISNODE->id, seqno); 645 encode_header (enc, THISNODE->id, seqno);
… …
609 encp += lbllen; 663 encp += lbllen;
610 664
611 enclen -= lbllen; 665 enclen -= lbllen;
612 } 666 }
613 667
614 append_domain (*pkt, offs, THISNODE->domain); 668 append_domain (*pkt, offs, dns->c->conf->domain);
615 669
616 (*pkt)[offs++] = 0; 670 (*pkt)[offs++] = 0;
617 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 671 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
618 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 672 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
619 673
620 pkt->len = offs; 674 pkt->len = offs;
621} 675}
622 676
623void dns_snd::gen_syn_req (const dns_cfg &cfg) 677void dns_snd::gen_syn_req ()
624{ 678{
625 timeout = NOW + INITIAL_SYN_TIMEOUT; 679 timeout = NOW + INITIAL_SYN_TIMEOUT;
626 680
627 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 681 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
628 pkt->qdcount = htons (1); 682 pkt->qdcount = htons (1);
629 683
630 int offs = 6*2; 684 int offs = 6 * 2;
631 685
632 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); 686 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg));
633 687
634 assert (elen <= MAX_LBL_SIZE); 688 assert (elen <= MAX_LBL_SIZE);
635 689
636 (*pkt)[offs] = elen; 690 (*pkt)[offs] = elen;
637 offs += elen + 1; 691 offs += elen + 1;
638 append_domain (*pkt, offs, THISNODE->domain); 692 append_domain (*pkt, offs, dns->c->conf->domain);
639 693
640 (*pkt)[offs++] = 0; 694 (*pkt)[offs++] = 0;
641 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 695 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
642 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 696 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
643 697
… …
666 delete pkt; 720 delete pkt;
667} 721}
668 722
669///////////////////////////////////////////////////////////////////////////// 723/////////////////////////////////////////////////////////////////////////////
670 724
671struct dns_connection
672{
673 connection *c;
674 struct vpn *vpn;
675
676 dns_cfg cfg;
677
678 bool established;
679
680 tstamp last_received;
681 tstamp last_sent;
682 double last_latency;
683 double poll_interval, send_interval;
684
685 vector<dns_rcv *> rcvpq;
686
687 byte_stream rcvdq; int rcvseq;
688 byte_stream snddq; int sndseq;
689
690 void time_cb (time_watcher &w); time_watcher tw;
691 void receive_rep (dns_rcv *r);
692
693 dns_connection (connection *c);
694 ~dns_connection ();
695};
696
697dns_connection::dns_connection (connection *c) 725dns_connection::dns_connection (connection *c)
698: c (c) 726: c (c)
699, rcvdq (MAX_BACKLOG * 2) 727, rcvdq (MAX_BACKLOG * 2)
700, snddq (MAX_BACKLOG * 2) 728, snddq (MAX_BACKLOG)
701, tw (this, &dns_connection::time_cb) 729, tw (this, &dns_connection::time_cb)
702{ 730{
703 vpn = c->vpn; 731 vpn = c->vpn;
704 732
705 established = false; 733 established = false;
706 734
707 rcvseq = sndseq = 0; 735 rcvseq = repseq = sndseq = 0;
708 736
709 last_sent = last_received = 0; 737 last_sent = last_received = 0;
710 poll_interval = MIN_POLL_INTERVAL; 738 poll_interval = 0.5; // starting here
711 send_interval = 0.5; // starting rate 739 send_interval = 0.5; // starting rate
712 last_latency = INITIAL_TIMEOUT; 740 min_latency = INITIAL_TIMEOUT;
713} 741}
714 742
715dns_connection::~dns_connection () 743dns_connection::~dns_connection ()
716{ 744{
717 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 745 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
… …
730 poll_interval = send_interval; 758 poll_interval = send_interval;
731 } 759 }
732 else 760 else
733 { 761 {
734 poll_interval *= 1.5; 762 poll_interval *= 1.5;
763
735 if (poll_interval > MAX_POLL_INTERVAL) 764 if (poll_interval > MAX_POLL_INTERVAL)
736 poll_interval = MAX_POLL_INTERVAL; 765 poll_interval = MAX_POLL_INTERVAL;
737 } 766 }
738 767
739 rcvpq.push_back (r); 768 rcvpq.push_back (r);
… …
765 } 794 }
766 795
767 while (vpn_packet *pkt = rcvdq.get ()) 796 while (vpn_packet *pkt = rcvdq.get ())
768 { 797 {
769 sockinfo si; 798 sockinfo si;
770 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 799 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
771 800
772 vpn->recv_vpn_packet (pkt, si); 801 vpn->recv_vpn_packet (pkt, si);
773 802
774 delete pkt; 803 delete pkt;
775 } 804 }
… …
789 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 818 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
790 819
791 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 820 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
792 && pkt.qdcount == htons (1)) 821 && pkt.qdcount == htons (1))
793 { 822 {
794 char qname[MAXSIZE]; 823 char qname [MAXSIZE];
795 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 824 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
796 825
797 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 826 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
798 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 827 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
799 828
… …
806 835
807 int dlen = strlen (THISNODE->domain); 836 int dlen = strlen (THISNODE->domain);
808 837
809 if (qclass == RR_CLASS_IN 838 if (qclass == RR_CLASS_IN
810 && qlen > dlen + 1 839 && qlen > dlen + 1
811 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 840 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
812 { 841 {
813 // now generate reply 842 // now generate reply
814 pkt.ancount = htons (1); // one answer RR 843 pkt.ancount = htons (1); // one answer RR
815 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 844 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
816 845
… …
829 if (0 < client && client <= conns.size ()) 858 if (0 < client && client <= conns.size ())
830 { 859 {
831 connection *c = conns [client - 1]; 860 connection *c = conns [client - 1];
832 dns_connection *dns = c->dns; 861 dns_connection *dns = c->dns;
833 dns_rcv *rcv; 862 dns_rcv *rcv;
834 bool in_seq;
835 863
836 if (dns) 864 if (dns)
837 { 865 {
838 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 866 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
839 if (SEQNO_EQ ((*i)->seqno, seqno)) 867 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
850 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 878 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
851 879
852 goto duplicate_request; 880 goto duplicate_request;
853 } 881 }
854 882
855 in_seq = dns->rcvseq == seqno;
856
857 // new packet, queue 883 // new packet, queue
858 rcv = new dns_rcv (seqno, data, datalen); 884 rcv = new dns_rcv (seqno, data, datalen);
859 dns->receive_rep (rcv); 885 dns->receive_rep (rcv);
860 } 886 }
861 887
888 {
862 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 889 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
863 890
864 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 891 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
865 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 892 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
866 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 893 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
867 pkt [offs++] = 0; pkt [offs++] = 0; 894 pkt [offs++] = 0; pkt [offs++] = 0;
868 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 895 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
869 896
870 int rdlen_offs = offs += 2; 897 int rdlen_offs = offs += 2;
871 898
899 if (dns)
900 {
872 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 901 int dlen = ntohs (dns->cfg.max_size) - offs;
902
873 // bind doesn't compress well, so reduce further by one label length 903 // bind doesn't compress well, so reduce further by one label length
874 dlen -= qlen; 904 dlen -= qlen;
875 905
876 if (dns)
877 {
878 // only put data into in-order sequence packets, if 906 // only put data into in-order sequence packets, if
879 // we receive out-of-order packets we generate empty 907 // we receive out-of-order packets we generate empty
880 // replies 908 // replies
881 while (dlen > 1 && !dns->snddq.empty () && in_seq) 909 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
910 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
882 { 911 {
912 dns->repseq = seqno;
913
914 while (dlen > 1 && !dns->snddq.empty ())
915 {
883 int txtlen = dlen <= 255 ? dlen - 1 : 255; 916 int txtlen = dlen <= 255 ? dlen - 1 : 255;
884 917
885 if (txtlen > dns->snddq.size ()) 918 if (txtlen > dns->snddq.size ())
886 txtlen = dns->snddq.size (); 919 txtlen = dns->snddq.size ();
887 920
888 pkt[offs++] = txtlen; 921 pkt[offs++] = txtlen;
889 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 922 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
890 offs += txtlen; 923 offs += txtlen;
891 dns->snddq.remove (txtlen); 924 dns->snddq.remove (txtlen);
892 925
893 dlen -= txtlen + 1; 926 dlen -= txtlen + 1;
927 }
894 } 928 }
895 929
896 // avoid empty TXT rdata 930 // avoid completely empty TXT rdata
897 if (offs == rdlen_offs) 931 if (offs == rdlen_offs)
898 pkt[offs++] = 0; 932 pkt[offs++] = 0;
899 933
900 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 934 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
901 } 935 }
902 else 936 else
903 { 937 {
904 // send RST 938 // send RST
905 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 939 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
906 pkt [offs++] = CMD_IP_RST; 940 pkt [offs++] = CMD_IP_RST;
907 } 941 }
908 942
909 int rdlen = offs - rdlen_offs; 943 int rdlen = offs - rdlen_offs;
910 944
911 pkt [rdlen_offs - 2] = rdlen >> 8; 945 pkt [rdlen_offs - 2] = rdlen >> 8;
912 pkt [rdlen_offs - 1] = rdlen; 946 pkt [rdlen_offs - 1] = rdlen;
913 947
914 if (dns) 948 if (dns)
915 { 949 {
916 // now update dns_rcv copy 950 // now update dns_rcv copy
917 rcv->pkt->len = offs; 951 rcv->pkt->len = offs;
918 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 952 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
919 } 953 }
954 }
920 955
921 duplicate_request: ; 956 duplicate_request: ;
922 } 957 }
923 else 958 else
924 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 959 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
936 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 971 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
937 pkt [offs++] = 0; pkt [offs++] = 0; 972 pkt [offs++] = 0; pkt [offs++] = 0;
938 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 973 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
939 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 974 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
940 975
941 slog (L_INFO, _("DNS: client %d tries to connect"), client); 976 slog (L_INFO, _("DNS: client %d connects"), client);
942 977
943 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 978 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
944 pkt [offs++] = CMD_IP_REJ; 979 pkt [offs++] = CMD_IP_REJ;
945 980
946 if (0 < client && client <= conns.size ()) 981 if (0 < client && client <= conns.size ())
… …
989 if (dns->send_interval > MAX_SEND_INTERVAL) 1024 if (dns->send_interval > MAX_SEND_INTERVAL)
990 dns->send_interval = MAX_SEND_INTERVAL; 1025 dns->send_interval = MAX_SEND_INTERVAL;
991 } 1026 }
992 else 1027 else
993 { 1028 {
994#if 1 1029#if 0
995 dns->send_interval *= 0.999; 1030 dns->send_interval *= 0.999;
996#endif 1031#endif
997 if (dns->send_interval < MIN_SEND_INTERVAL)
998 dns->send_interval = MIN_SEND_INTERVAL;
999
1000 // the latency surely puts an upper bound on 1032 // the latency surely puts an upper bound on
1001 // the minimum send interval 1033 // the minimum send interval
1002 double latency = NOW - (*i)->sent; 1034 double latency = NOW - (*i)->sent;
1035
1036 if (latency < dns->min_latency)
1003 dns->last_latency = latency; 1037 dns->min_latency = latency;
1004 1038
1005 if (dns->send_interval > latency) 1039 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1040 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1041
1042 if (dns->send_interval < conf.dns_send_interval)
1006 dns->send_interval = latency; 1043 dns->send_interval = conf.dns_send_interval;
1007 } 1044 }
1008 1045
1009 delete *i; 1046 delete *i;
1010 dns_sndpq.erase (i); 1047 dns_sndpq.erase (i);
1011 1048
… …
1128 1165
1129 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1166 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1130 1167
1131 if (pkt->len > 0) 1168 if (pkt->len > 0)
1132 { 1169 {
1133 if (THISNODE->dns_port) 1170 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1171 dnsv4_client (*pkt);
1172 else
1134 { 1173 {
1135 dnsv4_server (*pkt); 1174 dnsv4_server (*pkt);
1136 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1175 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1137 } 1176 }
1138 else
1139 dnsv4_client (*pkt);
1140 1177
1141 delete pkt; 1178 delete pkt;
1142 } 1179 }
1143 } 1180 }
1144} 1181}
1145 1182
1146bool 1183bool
1147connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1184vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1148{ 1185{
1186 int client = ntohl (si.host);
1187
1188 assert (0 < client && client <= conns.size ());
1189
1190 connection *c = conns [client - 1];
1191
1149 if (!dns) 1192 if (!c->dns)
1150 dns = new dns_connection (this); 1193 c->dns = new dns_connection (c);
1151 1194
1152 if (!dns->snddq.put (pkt)) 1195 if (c->dns->snddq.put (pkt))
1153 return false;
1154
1155 dns->tw.trigger (); 1196 c->dns->tw.trigger ();
1156 1197
1198 // always return true even if the buffer overflows
1157 return true; 1199 return true;
1158} 1200}
1159 1201
1160void 1202void
1161connection::dnsv4_reset_connection () 1203connection::dnsv4_reset_connection ()
… …
1187 if (!send) 1229 if (!send)
1188 { 1230 {
1189 send = r; 1231 send = r;
1190 1232
1191 r->retry++; 1233 r->retry++;
1192 r->timeout = NOW + (r->retry * last_latency * 8.); 1234 r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor);
1193 1235
1194 // the following code changes the query section a bit, forcing 1236 // the following code changes the query section a bit, forcing
1195 // the forwarder to generate a new request 1237 // the forwarder to generate a new request
1196 if (r->stdhdr) 1238 if (r->stdhdr)
1197 { 1239 {
1198 //printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry); 1240 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1199 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1241 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1200 } 1242 }
1201 } 1243 }
1202 } 1244 }
1203 else 1245 else
1204 NEXT (r->timeout); 1246 NEXT (r->timeout);
1205 } 1247 }
1206 1248
1207 if (last_sent + send_interval <= NOW)
1208 {
1209 if (!send) 1249 if (!send)
1250 {
1251 // generate a new packet, if wise
1252
1253 if (!established)
1210 { 1254 {
1211 // generate a new packet, if wise 1255 if (vpn->dns_sndpq.empty ())
1212
1213 if (!established)
1214 { 1256 {
1215 if (vpn->dns_sndpq.empty ())
1216 {
1217 send = new dns_snd (this); 1257 send = new dns_snd (this);
1218 1258
1219 cfg.reset (THISNODE->id); 1259 cfg.reset (THISNODE->id);
1220 send->gen_syn_req (cfg); 1260 send->gen_syn_req ();
1221 }
1222 } 1261 }
1223 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1262 }
1263 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1224 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1264 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1265 {
1266 if (last_sent + send_interval <= NOW)
1225 { 1267 {
1226 if (!snddq.empty ()) 1268 //printf ("sending data request etc.\n"); //D
1269 if (!snddq.empty () || last_received + 1. > NOW)
1227 { 1270 {
1228 poll_interval = send_interval; 1271 poll_interval = send_interval;
1229 NEXT (NOW + send_interval); 1272 NEXT (NOW + send_interval);
1230 } 1273 }
1231 1274
1232 send = new dns_snd (this); 1275 send = new dns_snd (this);
1233 send->gen_stream_req (sndseq, snddq); 1276 send->gen_stream_req (sndseq, snddq);
1234 send->timeout = NOW + last_latency * 8.; 1277 send->timeout = NOW + min_latency * conf.dns_timeout_factor;
1235 1278
1236 sndseq = (sndseq + 1) & SEQNO_MASK; 1279 sndseq = (sndseq + 1) & SEQNO_MASK;
1237 } 1280 }
1238 1281 else
1239 if (send) 1282 NEXT (last_sent + send_interval);
1240 vpn->dns_sndpq.push_back (send);
1241 } 1283 }
1242 1284
1243 if (send) 1285 if (send)
1244 { 1286 vpn->dns_sndpq.push_back (send);
1287 }
1288
1289 if (send)
1290 {
1245 last_sent = NOW; 1291 last_sent = NOW;
1246 sendto (vpn->dnsv4_fd, 1292 sendto (vpn->dnsv4_fd,
1247 send->pkt->at (0), send->pkt->len, 0, 1293 send->pkt->at (0), send->pkt->len, 0,
1248 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1294 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1249 }
1250 } 1295 }
1251 else
1252 NEXT (last_sent + send_interval);
1253 1296
1254 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1297 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1255 poll_interval, send_interval, next - NOW, 1298 poll_interval, send_interval, next - NOW,
1256 vpn->dns_sndpq.size (), snddq.size ()); 1299 vpn->dns_sndpq.size (), snddq.size (),
1300 rcvpq.size ());
1257 1301
1258 // TODO: no idea when this happens, but when next < NOW, we have a problem 1302 // TODO: no idea when this happens, but when next < NOW, we have a problem
1303 // doesn't seem to happen anymore
1259 if (next < NOW + 0.0001) 1304 if (next < NOW + 0.001)
1260 next = NOW + 0.1; 1305 next = NOW + 0.1;
1261 1306
1262 w.start (next); 1307 w.start (next);
1263} 1308}
1264 1309

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