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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.20 by pcg, Sun Mar 6 21:32:15 2005 UTC vs.
Revision 1.48 by pcg, Tue Jul 28 00:42:14 2009 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
… …
265static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 278static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
266 279
267///////////////////////////////////////////////////////////////////////////// 280/////////////////////////////////////////////////////////////////////////////
268 281
269#define HDRSIZE 6 282#define HDRSIZE 6
270 283
271inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 284inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
272{ 285{
273 seqno &= SEQNO_MASK; 286 seqno &= SEQNO_MASK;
274 287
275 u8 hdr[3] = { 288 u8 hdr[3] = {
… …
409struct dns_cfg 422struct dns_cfg
410{ 423{
411 static int next_uid; 424 static int next_uid;
412 425
413 u8 id1, id2, id3, id4; 426 u8 id1, id2, id3, id4;
427
414 u8 version; 428 u8 version;
429 u8 flags;
415 u8 rrtype; 430 u8 rrtype;
416 u8 flags;
417 u8 def_ttl; 431 u8 def_ttl;
418 u8 rcv_cdc; 432
419 u8 snd_cdc;
420 u16 max_size;
421 u16 client; 433 u16 client;
422 u16 uid; // to make request unique 434 u16 uid; // to make request unique
423 435
424 u8 reserved[8]; 436 u16 max_size;
437 u8 seq_cdc;
438 u8 req_cdc;
439
440 u8 rep_cdc;
441 u8 delay; // time in 0.01s units that the server may delay replying packets
442 u8 r3, r4;
443
444 u8 r5, r6, r7, r8;
425 445
426 void reset (int clientid); 446 void reset (int clientid);
427 bool valid (); 447 bool valid ();
428}; 448};
429 449
… …
438 458
439 version = 1; 459 version = 1;
440 460
441 rrtype = RR_TYPE_TXT; 461 rrtype = RR_TYPE_TXT;
442 flags = 0; 462 flags = 0;
443 def_ttl = 1; 463 def_ttl = 0;
464 seq_cdc = 26;
465 req_cdc = 62;
444 rcv_cdc = 0; 466 rep_cdc = 0;
445 snd_cdc = 62;
446 max_size = ntohs (MAX_PKT_SIZE); 467 max_size = htons (MAX_PKT_SIZE);
447 client = ntohs (clientid); 468 client = htons (clientid);
448 uid = next_uid++; 469 uid = next_uid++;
470 delay = 0;
449 471
450 memset (reserved, 0, 8); 472 r3 = r4 = 0;
473 r4 = r5 = r6 = r7 = 0;
451} 474}
452 475
453bool dns_cfg::valid () 476bool dns_cfg::valid ()
454{ 477{
478 // although the protocol itself allows for some configurability,
479 // only the following encoding/decoding settings are implemented.
455 return id1 == 'G' 480 return id1 == 'G'
456 && id2 == 'V' 481 && id2 == 'V'
457 && id3 == 'P' 482 && id3 == 'P'
458 && id4 == 'E' 483 && id4 == 'E'
484 && seq_cdc == 26
485 && req_cdc == 62
486 && rep_cdc == 0
459 && version == 1 487 && version == 1;
460 && flags == 0
461 && rcv_cdc == 0
462 && snd_cdc == 62
463 && max_size == ntohs (MAX_PKT_SIZE);
464} 488}
465 489
466struct dns_packet : net_packet 490struct dns_packet : net_packet
467{ 491{
468 u16 id; 492 u16 id;
469 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 493 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
470 u16 qdcount, ancount, nscount, arcount; 494 u16 qdcount, ancount, nscount, arcount;
471 495
472 u8 data[MAXSIZE - 6 * 2]; 496 u8 data [MAXSIZE - 6 * 2];
473 497
474 int decode_label (char *data, int size, int &offs); 498 int decode_label (char *data, int size, int &offs);
475}; 499};
476 500
477int dns_packet::decode_label (char *data, int size, int &offs) 501int dns_packet::decode_label (char *data, int size, int &offs)
… …
539 563
540 bool established; 564 bool established;
541 565
542 tstamp last_received; 566 tstamp last_received;
543 tstamp last_sent; 567 tstamp last_sent;
544 double last_latency; 568 double min_latency;
545 double poll_interval, send_interval; 569 double poll_interval, send_interval;
546 570
547 vector<dns_rcv *> rcvpq; 571 vector<dns_rcv *> rcvpq;
548 572
549 byte_stream rcvdq; int rcvseq; 573 byte_stream rcvdq; int rcvseq; int repseq;
550 byte_stream snddq; int sndseq; 574 byte_stream snddq; int sndseq;
551 575
552 void time_cb (time_watcher &w); time_watcher tw; 576 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
553 void receive_rep (dns_rcv *r); 577 void receive_rep (dns_rcv *r);
554 578
555 dns_connection (connection *c); 579 dns_connection (connection *c);
556 ~dns_connection (); 580 ~dns_connection ();
557}; 581};
… …
576: dns (dns) 600: dns (dns)
577{ 601{
578 timeout = 0; 602 timeout = 0;
579 retry = 0; 603 retry = 0;
580 seqno = 0; 604 seqno = 0;
581 sent = NOW; 605 sent = ev_now ();
582 stdhdr = false; 606 stdhdr = false;
583 607
584 pkt = new dns_packet; 608 pkt = new dns_packet;
585 609
586 pkt->id = next_id (); 610 pkt->id = next_id ();
… …
617void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 641void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
618{ 642{
619 stdhdr = true; 643 stdhdr = true;
620 this->seqno = seqno; 644 this->seqno = seqno;
621 645
622 timeout = NOW + INITIAL_TIMEOUT; 646 timeout = ev_now () + INITIAL_TIMEOUT;
623 647
624 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 648 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
625 pkt->qdcount = htons (1); 649 pkt->qdcount = htons (1);
626 650
627 int offs = 6*2; 651 int offs = 6*2;
… …
662 pkt->len = offs; 686 pkt->len = offs;
663} 687}
664 688
665void dns_snd::gen_syn_req () 689void dns_snd::gen_syn_req ()
666{ 690{
667 timeout = NOW + INITIAL_SYN_TIMEOUT; 691 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
668
669 printf ("send syn\n");//D
670 692
671 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 693 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
672 pkt->qdcount = htons (1); 694 pkt->qdcount = htons (1);
673 695
674 int offs = 6 * 2; 696 int offs = 6 * 2;
… …
713///////////////////////////////////////////////////////////////////////////// 735/////////////////////////////////////////////////////////////////////////////
714 736
715dns_connection::dns_connection (connection *c) 737dns_connection::dns_connection (connection *c)
716: c (c) 738: c (c)
717, rcvdq (MAX_BACKLOG * 2) 739, rcvdq (MAX_BACKLOG * 2)
718, snddq (MAX_BACKLOG * 2) 740, snddq (MAX_BACKLOG)
719, tw (this, &dns_connection::time_cb)
720{ 741{
742 tw.set<dns_connection, &dns_connection::time_cb> (this);
743
721 vpn = c->vpn; 744 vpn = c->vpn;
722 745
723 established = false; 746 established = false;
724 747
725 rcvseq = sndseq = 0; 748 rcvseq = repseq = sndseq = 0;
726 749
727 last_sent = last_received = 0; 750 last_sent = last_received = 0;
728 poll_interval = MIN_POLL_INTERVAL; 751 poll_interval = 0.5; // starting here
729 send_interval = 0.5; // starting rate 752 send_interval = 0.5; // starting rate
730 last_latency = INITIAL_TIMEOUT; 753 min_latency = INITIAL_TIMEOUT;
731} 754}
732 755
733dns_connection::~dns_connection () 756dns_connection::~dns_connection ()
734{ 757{
735 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 758 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
… …
740 763
741void dns_connection::receive_rep (dns_rcv *r) 764void dns_connection::receive_rep (dns_rcv *r)
742{ 765{
743 if (r->datalen) 766 if (r->datalen)
744 { 767 {
745 last_received = NOW; 768 last_received = ev_now ();
746 tw.trigger (); 769 tw ();
747 770
748 poll_interval = send_interval; 771 poll_interval = send_interval;
749 } 772 }
750 else 773 else
751 { 774 {
752 poll_interval *= 1.5; 775 poll_interval *= 1.5;
776
753 if (poll_interval > MAX_POLL_INTERVAL) 777 if (poll_interval > MAX_POLL_INTERVAL)
754 poll_interval = MAX_POLL_INTERVAL; 778 poll_interval = MAX_POLL_INTERVAL;
755 } 779 }
756 780
757 rcvpq.push_back (r); 781 rcvpq.push_back (r);
… …
760 784
761 // find next packet 785 // find next packet
762 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 786 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
763 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 787 if (SEQNO_EQ (rcvseq, (*i)->seqno))
764 { 788 {
789 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
765 // enter the packet into our input stream 790 // enter the packet into our input stream
766 r = *i; 791 r = *i;
767 792
768 // remove the oldest packet, look forward, as it's oldest first 793 // remove the oldest packet, look forward, as it's oldest first
769 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 794 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
770 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 795 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
771 { 796 {
797 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
772 delete *j; 798 delete *j;
773 rcvpq.erase (j); 799 rcvpq.erase (j);
774 break; 800 break;
775 } 801 }
776 802
… …
783 } 809 }
784 810
785 while (vpn_packet *pkt = rcvdq.get ()) 811 while (vpn_packet *pkt = rcvdq.get ())
786 { 812 {
787 sockinfo si; 813 sockinfo si;
788 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 814 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
789 815
790 vpn->recv_vpn_packet (pkt, si); 816 vpn->recv_vpn_packet (pkt, si);
791 817
792 delete pkt; 818 delete pkt;
793 } 819 }
… …
807 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 833 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
808 834
809 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 835 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
810 && pkt.qdcount == htons (1)) 836 && pkt.qdcount == htons (1))
811 { 837 {
812 char qname[MAXSIZE]; 838 char qname [MAXSIZE];
813 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 839 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
814 840
815 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 841 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
816 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 842 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
817 843
… …
824 850
825 int dlen = strlen (THISNODE->domain); 851 int dlen = strlen (THISNODE->domain);
826 852
827 if (qclass == RR_CLASS_IN 853 if (qclass == RR_CLASS_IN
828 && qlen > dlen + 1 854 && qlen > dlen + 1
829 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 855 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
830 { 856 {
831 // now generate reply 857 // now generate reply
832 pkt.ancount = htons (1); // one answer RR 858 pkt.ancount = htons (1); // one answer RR
833 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 859 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
834 860
… …
847 if (0 < client && client <= conns.size ()) 873 if (0 < client && client <= conns.size ())
848 { 874 {
849 connection *c = conns [client - 1]; 875 connection *c = conns [client - 1];
850 dns_connection *dns = c->dns; 876 dns_connection *dns = c->dns;
851 dns_rcv *rcv; 877 dns_rcv *rcv;
852 bool in_seq;
853 878
854 if (dns) 879 if (dns)
855 { 880 {
856 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 881 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
857 if (SEQNO_EQ ((*i)->seqno, seqno)) 882 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
868 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 893 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
869 894
870 goto duplicate_request; 895 goto duplicate_request;
871 } 896 }
872 897
873 in_seq = dns->rcvseq == seqno;
874
875 // new packet, queue 898 // new packet, queue
876 rcv = new dns_rcv (seqno, data, datalen); 899 rcv = new dns_rcv (seqno, data, datalen);
877 dns->receive_rep (rcv); 900 dns->receive_rep (rcv);
878 } 901 }
879 902
903 {
880 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 904 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
881 905
882 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 906 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
883 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 907 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
884 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 908 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
885 pkt [offs++] = 0; pkt [offs++] = 0; 909 pkt [offs++] = 0; pkt [offs++] = 0;
886 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 910 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
887 911
888 int rdlen_offs = offs += 2; 912 int rdlen_offs = offs += 2;
889 913
914 if (dns)
915 {
890 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 916 int dlen = ntohs (dns->cfg.max_size) - offs;
917
891 // bind doesn't compress well, so reduce further by one label length 918 // bind doesn't compress well, so reduce further by one label length
892 dlen -= qlen; 919 dlen -= qlen;
893 920
894 if (dns)
895 {
896 // only put data into in-order sequence packets, if 921 // only put data into in-order sequence packets, if
897 // we receive out-of-order packets we generate empty 922 // we receive out-of-order packets we generate empty
898 // replies 923 // replies
899 while (dlen > 1 && !dns->snddq.empty () && in_seq) 924 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
925 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
900 { 926 {
927 dns->repseq = seqno;
928
929 while (dlen > 1 && !dns->snddq.empty ())
930 {
901 int txtlen = dlen <= 255 ? dlen - 1 : 255; 931 int txtlen = dlen <= 255 ? dlen - 1 : 255;
902 932
903 if (txtlen > dns->snddq.size ()) 933 if (txtlen > dns->snddq.size ())
904 txtlen = dns->snddq.size (); 934 txtlen = dns->snddq.size ();
905 935
906 pkt[offs++] = txtlen; 936 pkt[offs++] = txtlen;
907 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 937 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
908 offs += txtlen; 938 offs += txtlen;
909 dns->snddq.remove (txtlen); 939 dns->snddq.remove (txtlen);
910 940
911 dlen -= txtlen + 1; 941 dlen -= txtlen + 1;
942 }
912 } 943 }
913 944
914 // avoid empty TXT rdata 945 // avoid completely empty TXT rdata
915 if (offs == rdlen_offs) 946 if (offs == rdlen_offs)
916 pkt[offs++] = 0; 947 pkt[offs++] = 0;
917 948
918 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 949 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
919 } 950 }
920 else 951 else
921 { 952 {
922 // send RST 953 // send RST
923 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 954 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
924 pkt [offs++] = CMD_IP_RST; 955 pkt [offs++] = CMD_IP_RST;
925 } 956 }
926 957
927 int rdlen = offs - rdlen_offs; 958 int rdlen = offs - rdlen_offs;
928 959
929 pkt [rdlen_offs - 2] = rdlen >> 8; 960 pkt [rdlen_offs - 2] = rdlen >> 8;
930 pkt [rdlen_offs - 1] = rdlen; 961 pkt [rdlen_offs - 1] = rdlen;
931 962
932 if (dns) 963 if (dns)
933 { 964 {
934 // now update dns_rcv copy 965 // now update dns_rcv copy
935 rcv->pkt->len = offs; 966 rcv->pkt->len = offs;
936 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 967 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
937 } 968 }
969 }
938 970
939 duplicate_request: ; 971 duplicate_request: ;
940 } 972 }
941 else 973 else
942 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 974 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
954 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 986 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
955 pkt [offs++] = 0; pkt [offs++] = 0; 987 pkt [offs++] = 0; pkt [offs++] = 0;
956 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 988 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
957 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 989 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
958 990
959 slog (L_INFO, _("DNS: client %d tries to connect"), client); 991 slog (L_INFO, _("DNS: client %d connects"), client);
960 992
961 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 993 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
962 pkt [offs++] = CMD_IP_REJ; 994 pkt [offs++] = CMD_IP_REJ;
963 995
964 if (0 < client && client <= conns.size ()) 996 if (0 < client && client <= conns.size ())
… …
998 { 1030 {
999 dns_connection *dns = (*i)->dns; 1031 dns_connection *dns = (*i)->dns;
1000 connection *c = dns->c; 1032 connection *c = dns->c;
1001 int seqno = (*i)->seqno; 1033 int seqno = (*i)->seqno;
1002 u8 data[MAXSIZE], *datap = data; 1034 u8 data[MAXSIZE], *datap = data;
1035 //printf ("rcv pkt %x\n", seqno);//D
1003 1036
1004 if ((*i)->retry) 1037 if ((*i)->retry)
1005 { 1038 {
1006 dns->send_interval *= 1.01; 1039 dns->send_interval *= 1.01;
1007 if (dns->send_interval > MAX_SEND_INTERVAL) 1040 if (dns->send_interval > MAX_SEND_INTERVAL)
1008 dns->send_interval = MAX_SEND_INTERVAL; 1041 dns->send_interval = MAX_SEND_INTERVAL;
1009 } 1042 }
1010 else 1043 else
1011 { 1044 {
1012#if 1 1045#if 0
1013 dns->send_interval *= 0.999; 1046 dns->send_interval *= 0.999;
1014#endif 1047#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 1048 // the latency surely puts an upper bound on
1019 // the minimum send interval 1049 // the minimum send interval
1020 double latency = NOW - (*i)->sent; 1050 double latency = ev_now () - (*i)->sent;
1051
1052 if (latency < dns->min_latency)
1021 dns->last_latency = latency; 1053 dns->min_latency = latency;
1022 1054
1023 if (dns->send_interval > latency) 1055 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1056 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1057
1058 if (dns->send_interval < conf.dns_send_interval)
1024 dns->send_interval = latency; 1059 dns->send_interval = conf.dns_send_interval;
1025 } 1060 }
1026 1061
1027 delete *i; 1062 delete *i;
1028 dns_sndpq.erase (i); 1063 dns_sndpq.erase (i);
1029 1064
… …
1134 break; 1169 break;
1135 } 1170 }
1136} 1171}
1137 1172
1138void 1173void
1139vpn::dnsv4_ev (io_watcher &w, short revents) 1174vpn::dnsv4_ev (ev::io &w, int revents)
1140{ 1175{
1141 if (revents & EVENT_READ) 1176 if (revents & EV_READ)
1142 { 1177 {
1143 dns_packet *pkt = new dns_packet; 1178 dns_packet *pkt = new dns_packet;
1144 struct sockaddr_in sa; 1179 struct sockaddr_in sa;
1145 socklen_t sa_len = sizeof (sa); 1180 socklen_t sa_len = sizeof (sa);
1146 1181
1147 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1182 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1148 1183
1149 if (pkt->len > 0) 1184 if (pkt->len > 0)
1150 { 1185 {
1151 if (THISNODE->dns_port) 1186 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1187 dnsv4_client (*pkt);
1188 else
1152 { 1189 {
1153 dnsv4_server (*pkt); 1190 dnsv4_server (*pkt);
1154 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1191 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1155 } 1192 }
1156 else
1157 dnsv4_client (*pkt);
1158 1193
1159 delete pkt; 1194 delete pkt;
1160 } 1195 }
1161 } 1196 }
1162} 1197}
1163 1198
1164bool 1199bool
1165vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1200vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1166{ 1201{
1167 int client = ntohs (si.port); 1202 int client = ntohl (si.host);
1168 1203
1169 assert (0 < client && client <= conns.size ()); 1204 assert (0 < client && client <= conns.size ());
1170 1205
1171 connection *c = conns [client - 1]; 1206 connection *c = conns [client - 1];
1172 1207
1173 if (!c->dns) 1208 if (!c->dns)
1174 c->dns = new dns_connection (c); 1209 c->dns = new dns_connection (c);
1175 1210
1176 if (!c->dns->snddq.put (pkt)) 1211 if (c->dns->snddq.put (pkt))
1177 return false;
1178
1179 c->dns->tw.trigger (); 1212 c->dns->tw ();
1180 1213
1214 // always return true even if the buffer overflows
1181 return true; 1215 return true;
1182} 1216}
1183 1217
1184void 1218void
1185connection::dnsv4_reset_connection () 1219connection::dnsv4_reset_connection ()
… …
1188} 1222}
1189 1223
1190#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1224#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1191 1225
1192void 1226void
1193dns_connection::time_cb (time_watcher &w) 1227dns_connection::time_cb (ev::timer &w, int revents)
1194{ 1228{
1195 // servers have to be polled 1229 // servers have to be polled
1196 if (THISNODE->dns_port) 1230 if (THISNODE->dns_port)
1197 return; 1231 return;
1198 1232
1199 // check for timeouts and (re)transmit 1233 // check for timeouts and (re)transmit
1200 tstamp next = NOW + poll_interval; 1234 tstamp next = ev::now () + poll_interval;
1201 dns_snd *send = 0; 1235 dns_snd *send = 0;
1202 1236
1203 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1237 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1204 i != vpn->dns_sndpq.end (); 1238 i != vpn->dns_sndpq.end ();
1205 ++i) 1239 ++i)
1206 { 1240 {
1207 dns_snd *r = *i; 1241 dns_snd *r = *i;
1208 1242
1209 if (r->timeout <= NOW) 1243 if (r->timeout <= ev_now ())
1210 { 1244 {
1211 if (!send) 1245 if (!send)
1212 { 1246 {
1213 send = r; 1247 send = r;
1214 1248
1215 r->retry++; 1249 r->retry++;
1216 r->timeout = NOW + (r->retry * last_latency * 8.); 1250 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1251 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1217 1252
1218 // the following code changes the query section a bit, forcing 1253 // the following code changes the query section a bit, forcing
1219 // the forwarder to generate a new request 1254 // the forwarder to generate a new request
1220 if (r->stdhdr) 1255 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); 1256 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1224 }
1225 } 1257 }
1226 } 1258 }
1227 else 1259 else
1228 NEXT (r->timeout); 1260 NEXT (r->timeout);
1229 } 1261 }
1230 1262
1231 if (last_sent + send_interval <= NOW)
1232 {
1233 if (!send) 1263 if (!send)
1264 {
1265 // generate a new packet, if wise
1266
1267 if (!established)
1234 { 1268 {
1235 // generate a new packet, if wise 1269 if (vpn->dns_sndpq.empty ())
1236
1237 if (!established)
1238 { 1270 {
1239 if (vpn->dns_sndpq.empty ())
1240 {
1241 send = new dns_snd (this); 1271 send = new dns_snd (this);
1242 1272
1243 printf ("new conn %p %d\n", this, c->conf->id);//D
1244 cfg.reset (THISNODE->id); 1273 cfg.reset (THISNODE->id);
1245 send->gen_syn_req (); 1274 send->gen_syn_req ();
1246 }
1247 } 1275 }
1248 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1276 }
1277 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1249 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1278 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1279 {
1280 if (last_sent + send_interval <= ev_now ())
1250 { 1281 {
1251 //printf ("sending data request etc.\n"); //D 1282 //printf ("sending data request etc.\n"); //D
1252 if (!snddq.empty ()) 1283 if (!snddq.empty () || last_received + 1. > ev_now ())
1253 { 1284 {
1254 poll_interval = send_interval; 1285 poll_interval = send_interval;
1255 NEXT (NOW + send_interval); 1286 NEXT (ev_now () + send_interval);
1256 } 1287 }
1257 1288
1258 send = new dns_snd (this); 1289 send = new dns_snd (this);
1259 send->gen_stream_req (sndseq, snddq); 1290 send->gen_stream_req (sndseq, snddq);
1260 send->timeout = NOW + last_latency * 8.; 1291 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1292 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1261 1293
1262 sndseq = (sndseq + 1) & SEQNO_MASK; 1294 sndseq = (sndseq + 1) & SEQNO_MASK;
1263 } 1295 }
1264 1296 else
1265 if (send) 1297 NEXT (last_sent + send_interval);
1266 vpn->dns_sndpq.push_back (send);
1267 } 1298 }
1268 1299
1269 if (send) 1300 if (send)
1270 { 1301 vpn->dns_sndpq.push_back (send);
1271 last_sent = NOW; 1302 }
1303
1304 if (send)
1305 {
1306 last_sent = ev_now ();
1272 sendto (vpn->dnsv4_fd, 1307 sendto (vpn->dnsv4_fd,
1273 send->pkt->at (0), send->pkt->len, 0, 1308 send->pkt->at (0), send->pkt->len, 0,
1274 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1309 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1275 }
1276 } 1310 }
1277 else
1278 NEXT (last_sent + send_interval);
1279 1311
1280 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1312 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1281 poll_interval, send_interval, next - NOW, 1313 poll_interval, send_interval, next - ev_now (),
1282 vpn->dns_sndpq.size (), snddq.size ()); 1314 vpn->dns_sndpq.size (), snddq.size (),
1315 rcvpq.size ());
1283 1316
1284 // TODO: no idea when this happens, but when next < NOW, we have a problem 1317 // TODO: no idea when this happens, but when next < ev_now (), we have a problem
1318 // doesn't seem to happen anymore
1285 if (next < NOW + 0.0001) 1319 if (next < ev_now () + 0.001)
1286 next = NOW + 0.1; 1320 next = ev_now () + 0.1;
1287 1321
1288 w.start (next); 1322 w.start (next - ev_now ());
1289} 1323}
1290 1324
1291#endif 1325#endif
1292 1326

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