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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.20 by pcg, Sun Mar 6 21:32:15 2005 UTC vs.
Revision 1.47 by pcg, Thu Aug 7 17:54:27 2008 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
… …
265static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 277static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
266 278
267///////////////////////////////////////////////////////////////////////////// 279/////////////////////////////////////////////////////////////////////////////
268 280
269#define HDRSIZE 6 281#define HDRSIZE 6
270 282
271inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 283inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
272{ 284{
273 seqno &= SEQNO_MASK; 285 seqno &= SEQNO_MASK;
274 286
275 u8 hdr[3] = { 287 u8 hdr[3] = {
… …
409struct dns_cfg 421struct dns_cfg
410{ 422{
411 static int next_uid; 423 static int next_uid;
412 424
413 u8 id1, id2, id3, id4; 425 u8 id1, id2, id3, id4;
426
414 u8 version; 427 u8 version;
428 u8 flags;
415 u8 rrtype; 429 u8 rrtype;
416 u8 flags;
417 u8 def_ttl; 430 u8 def_ttl;
418 u8 rcv_cdc; 431
419 u8 snd_cdc;
420 u16 max_size;
421 u16 client; 432 u16 client;
422 u16 uid; // to make request unique 433 u16 uid; // to make request unique
423 434
424 u8 reserved[8]; 435 u16 max_size;
436 u8 seq_cdc;
437 u8 req_cdc;
438
439 u8 rep_cdc;
440 u8 delay; // time in 0.01s units that the server may delay replying packets
441 u8 r3, r4;
442
443 u8 r5, r6, r7, r8;
425 444
426 void reset (int clientid); 445 void reset (int clientid);
427 bool valid (); 446 bool valid ();
428}; 447};
429 448
… …
438 457
439 version = 1; 458 version = 1;
440 459
441 rrtype = RR_TYPE_TXT; 460 rrtype = RR_TYPE_TXT;
442 flags = 0; 461 flags = 0;
443 def_ttl = 1; 462 def_ttl = 0;
463 seq_cdc = 26;
464 req_cdc = 62;
444 rcv_cdc = 0; 465 rep_cdc = 0;
445 snd_cdc = 62;
446 max_size = ntohs (MAX_PKT_SIZE); 466 max_size = htons (MAX_PKT_SIZE);
447 client = ntohs (clientid); 467 client = htons (clientid);
448 uid = next_uid++; 468 uid = next_uid++;
469 delay = 0;
449 470
450 memset (reserved, 0, 8); 471 r3 = r4 = 0;
472 r4 = r5 = r6 = r7 = 0;
451} 473}
452 474
453bool dns_cfg::valid () 475bool dns_cfg::valid ()
454{ 476{
477 // although the protocol itself allows for some configurability,
478 // only the following encoding/decoding settings are implemented.
455 return id1 == 'G' 479 return id1 == 'G'
456 && id2 == 'V' 480 && id2 == 'V'
457 && id3 == 'P' 481 && id3 == 'P'
458 && id4 == 'E' 482 && id4 == 'E'
483 && seq_cdc == 26
484 && req_cdc == 62
485 && rep_cdc == 0
459 && version == 1 486 && version == 1;
460 && flags == 0
461 && rcv_cdc == 0
462 && snd_cdc == 62
463 && max_size == ntohs (MAX_PKT_SIZE);
464} 487}
465 488
466struct dns_packet : net_packet 489struct dns_packet : net_packet
467{ 490{
468 u16 id; 491 u16 id;
469 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 492 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
470 u16 qdcount, ancount, nscount, arcount; 493 u16 qdcount, ancount, nscount, arcount;
471 494
472 u8 data[MAXSIZE - 6 * 2]; 495 u8 data [MAXSIZE - 6 * 2];
473 496
474 int decode_label (char *data, int size, int &offs); 497 int decode_label (char *data, int size, int &offs);
475}; 498};
476 499
477int dns_packet::decode_label (char *data, int size, int &offs) 500int dns_packet::decode_label (char *data, int size, int &offs)
… …
539 562
540 bool established; 563 bool established;
541 564
542 tstamp last_received; 565 tstamp last_received;
543 tstamp last_sent; 566 tstamp last_sent;
544 double last_latency; 567 double min_latency;
545 double poll_interval, send_interval; 568 double poll_interval, send_interval;
546 569
547 vector<dns_rcv *> rcvpq; 570 vector<dns_rcv *> rcvpq;
548 571
549 byte_stream rcvdq; int rcvseq; 572 byte_stream rcvdq; int rcvseq; int repseq;
550 byte_stream snddq; int sndseq; 573 byte_stream snddq; int sndseq;
551 574
552 void time_cb (time_watcher &w); time_watcher tw; 575 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
553 void receive_rep (dns_rcv *r); 576 void receive_rep (dns_rcv *r);
554 577
555 dns_connection (connection *c); 578 dns_connection (connection *c);
556 ~dns_connection (); 579 ~dns_connection ();
557}; 580};
… …
576: dns (dns) 599: dns (dns)
577{ 600{
578 timeout = 0; 601 timeout = 0;
579 retry = 0; 602 retry = 0;
580 seqno = 0; 603 seqno = 0;
581 sent = NOW; 604 sent = ev_now ();
582 stdhdr = false; 605 stdhdr = false;
583 606
584 pkt = new dns_packet; 607 pkt = new dns_packet;
585 608
586 pkt->id = next_id (); 609 pkt->id = next_id ();
… …
617void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 640void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
618{ 641{
619 stdhdr = true; 642 stdhdr = true;
620 this->seqno = seqno; 643 this->seqno = seqno;
621 644
622 timeout = NOW + INITIAL_TIMEOUT; 645 timeout = ev_now () + INITIAL_TIMEOUT;
623 646
624 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 647 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
625 pkt->qdcount = htons (1); 648 pkt->qdcount = htons (1);
626 649
627 int offs = 6*2; 650 int offs = 6*2;
… …
662 pkt->len = offs; 685 pkt->len = offs;
663} 686}
664 687
665void dns_snd::gen_syn_req () 688void dns_snd::gen_syn_req ()
666{ 689{
667 timeout = NOW + INITIAL_SYN_TIMEOUT; 690 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
668
669 printf ("send syn\n");//D
670 691
671 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 692 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
672 pkt->qdcount = htons (1); 693 pkt->qdcount = htons (1);
673 694
674 int offs = 6 * 2; 695 int offs = 6 * 2;
… …
713///////////////////////////////////////////////////////////////////////////// 734/////////////////////////////////////////////////////////////////////////////
714 735
715dns_connection::dns_connection (connection *c) 736dns_connection::dns_connection (connection *c)
716: c (c) 737: c (c)
717, rcvdq (MAX_BACKLOG * 2) 738, rcvdq (MAX_BACKLOG * 2)
718, snddq (MAX_BACKLOG * 2) 739, snddq (MAX_BACKLOG)
719, tw (this, &dns_connection::time_cb)
720{ 740{
741 tw.set<dns_connection, &dns_connection::time_cb> (this);
742
721 vpn = c->vpn; 743 vpn = c->vpn;
722 744
723 established = false; 745 established = false;
724 746
725 rcvseq = sndseq = 0; 747 rcvseq = repseq = sndseq = 0;
726 748
727 last_sent = last_received = 0; 749 last_sent = last_received = 0;
728 poll_interval = MIN_POLL_INTERVAL; 750 poll_interval = 0.5; // starting here
729 send_interval = 0.5; // starting rate 751 send_interval = 0.5; // starting rate
730 last_latency = INITIAL_TIMEOUT; 752 min_latency = INITIAL_TIMEOUT;
731} 753}
732 754
733dns_connection::~dns_connection () 755dns_connection::~dns_connection ()
734{ 756{
735 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 757 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
… …
740 762
741void dns_connection::receive_rep (dns_rcv *r) 763void dns_connection::receive_rep (dns_rcv *r)
742{ 764{
743 if (r->datalen) 765 if (r->datalen)
744 { 766 {
745 last_received = NOW; 767 last_received = ev_now ();
746 tw.trigger (); 768 tw ();
747 769
748 poll_interval = send_interval; 770 poll_interval = send_interval;
749 } 771 }
750 else 772 else
751 { 773 {
752 poll_interval *= 1.5; 774 poll_interval *= 1.5;
775
753 if (poll_interval > MAX_POLL_INTERVAL) 776 if (poll_interval > MAX_POLL_INTERVAL)
754 poll_interval = MAX_POLL_INTERVAL; 777 poll_interval = MAX_POLL_INTERVAL;
755 } 778 }
756 779
757 rcvpq.push_back (r); 780 rcvpq.push_back (r);
… …
760 783
761 // find next packet 784 // find next packet
762 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 785 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
763 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 786 if (SEQNO_EQ (rcvseq, (*i)->seqno))
764 { 787 {
788 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
765 // enter the packet into our input stream 789 // enter the packet into our input stream
766 r = *i; 790 r = *i;
767 791
768 // remove the oldest packet, look forward, as it's oldest first 792 // remove the oldest packet, look forward, as it's oldest first
769 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 793 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
770 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 794 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
771 { 795 {
796 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
772 delete *j; 797 delete *j;
773 rcvpq.erase (j); 798 rcvpq.erase (j);
774 break; 799 break;
775 } 800 }
776 801
… …
783 } 808 }
784 809
785 while (vpn_packet *pkt = rcvdq.get ()) 810 while (vpn_packet *pkt = rcvdq.get ())
786 { 811 {
787 sockinfo si; 812 sockinfo si;
788 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 813 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
789 814
790 vpn->recv_vpn_packet (pkt, si); 815 vpn->recv_vpn_packet (pkt, si);
791 816
792 delete pkt; 817 delete pkt;
793 } 818 }
… …
807 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 832 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
808 833
809 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 834 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
810 && pkt.qdcount == htons (1)) 835 && pkt.qdcount == htons (1))
811 { 836 {
812 char qname[MAXSIZE]; 837 char qname [MAXSIZE];
813 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 838 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
814 839
815 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 840 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
816 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 841 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
817 842
… …
824 849
825 int dlen = strlen (THISNODE->domain); 850 int dlen = strlen (THISNODE->domain);
826 851
827 if (qclass == RR_CLASS_IN 852 if (qclass == RR_CLASS_IN
828 && qlen > dlen + 1 853 && qlen > dlen + 1
829 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 854 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
830 { 855 {
831 // now generate reply 856 // now generate reply
832 pkt.ancount = htons (1); // one answer RR 857 pkt.ancount = htons (1); // one answer RR
833 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 858 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
834 859
… …
847 if (0 < client && client <= conns.size ()) 872 if (0 < client && client <= conns.size ())
848 { 873 {
849 connection *c = conns [client - 1]; 874 connection *c = conns [client - 1];
850 dns_connection *dns = c->dns; 875 dns_connection *dns = c->dns;
851 dns_rcv *rcv; 876 dns_rcv *rcv;
852 bool in_seq;
853 877
854 if (dns) 878 if (dns)
855 { 879 {
856 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 880 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
857 if (SEQNO_EQ ((*i)->seqno, seqno)) 881 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
868 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 892 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
869 893
870 goto duplicate_request; 894 goto duplicate_request;
871 } 895 }
872 896
873 in_seq = dns->rcvseq == seqno;
874
875 // new packet, queue 897 // new packet, queue
876 rcv = new dns_rcv (seqno, data, datalen); 898 rcv = new dns_rcv (seqno, data, datalen);
877 dns->receive_rep (rcv); 899 dns->receive_rep (rcv);
878 } 900 }
879 901
902 {
880 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 903 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
881 904
882 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 905 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
883 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 906 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
884 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 907 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
885 pkt [offs++] = 0; pkt [offs++] = 0; 908 pkt [offs++] = 0; pkt [offs++] = 0;
886 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 909 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
887 910
888 int rdlen_offs = offs += 2; 911 int rdlen_offs = offs += 2;
889 912
913 if (dns)
914 {
890 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 915 int dlen = ntohs (dns->cfg.max_size) - offs;
916
891 // bind doesn't compress well, so reduce further by one label length 917 // bind doesn't compress well, so reduce further by one label length
892 dlen -= qlen; 918 dlen -= qlen;
893 919
894 if (dns)
895 {
896 // only put data into in-order sequence packets, if 920 // only put data into in-order sequence packets, if
897 // we receive out-of-order packets we generate empty 921 // we receive out-of-order packets we generate empty
898 // replies 922 // replies
899 while (dlen > 1 && !dns->snddq.empty () && in_seq) 923 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
924 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
900 { 925 {
926 dns->repseq = seqno;
927
928 while (dlen > 1 && !dns->snddq.empty ())
929 {
901 int txtlen = dlen <= 255 ? dlen - 1 : 255; 930 int txtlen = dlen <= 255 ? dlen - 1 : 255;
902 931
903 if (txtlen > dns->snddq.size ()) 932 if (txtlen > dns->snddq.size ())
904 txtlen = dns->snddq.size (); 933 txtlen = dns->snddq.size ();
905 934
906 pkt[offs++] = txtlen; 935 pkt[offs++] = txtlen;
907 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 936 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
908 offs += txtlen; 937 offs += txtlen;
909 dns->snddq.remove (txtlen); 938 dns->snddq.remove (txtlen);
910 939
911 dlen -= txtlen + 1; 940 dlen -= txtlen + 1;
941 }
912 } 942 }
913 943
914 // avoid empty TXT rdata 944 // avoid completely empty TXT rdata
915 if (offs == rdlen_offs) 945 if (offs == rdlen_offs)
916 pkt[offs++] = 0; 946 pkt[offs++] = 0;
917 947
918 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 948 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
919 } 949 }
920 else 950 else
921 { 951 {
922 // send RST 952 // send RST
923 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 953 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
924 pkt [offs++] = CMD_IP_RST; 954 pkt [offs++] = CMD_IP_RST;
925 } 955 }
926 956
927 int rdlen = offs - rdlen_offs; 957 int rdlen = offs - rdlen_offs;
928 958
929 pkt [rdlen_offs - 2] = rdlen >> 8; 959 pkt [rdlen_offs - 2] = rdlen >> 8;
930 pkt [rdlen_offs - 1] = rdlen; 960 pkt [rdlen_offs - 1] = rdlen;
931 961
932 if (dns) 962 if (dns)
933 { 963 {
934 // now update dns_rcv copy 964 // now update dns_rcv copy
935 rcv->pkt->len = offs; 965 rcv->pkt->len = offs;
936 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 966 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
937 } 967 }
968 }
938 969
939 duplicate_request: ; 970 duplicate_request: ;
940 } 971 }
941 else 972 else
942 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 973 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
954 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 985 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
955 pkt [offs++] = 0; pkt [offs++] = 0; 986 pkt [offs++] = 0; pkt [offs++] = 0;
956 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 987 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
957 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 988 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
958 989
959 slog (L_INFO, _("DNS: client %d tries to connect"), client); 990 slog (L_INFO, _("DNS: client %d connects"), client);
960 991
961 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 992 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
962 pkt [offs++] = CMD_IP_REJ; 993 pkt [offs++] = CMD_IP_REJ;
963 994
964 if (0 < client && client <= conns.size ()) 995 if (0 < client && client <= conns.size ())
… …
998 { 1029 {
999 dns_connection *dns = (*i)->dns; 1030 dns_connection *dns = (*i)->dns;
1000 connection *c = dns->c; 1031 connection *c = dns->c;
1001 int seqno = (*i)->seqno; 1032 int seqno = (*i)->seqno;
1002 u8 data[MAXSIZE], *datap = data; 1033 u8 data[MAXSIZE], *datap = data;
1034 //printf ("rcv pkt %x\n", seqno);//D
1003 1035
1004 if ((*i)->retry) 1036 if ((*i)->retry)
1005 { 1037 {
1006 dns->send_interval *= 1.01; 1038 dns->send_interval *= 1.01;
1007 if (dns->send_interval > MAX_SEND_INTERVAL) 1039 if (dns->send_interval > MAX_SEND_INTERVAL)
1008 dns->send_interval = MAX_SEND_INTERVAL; 1040 dns->send_interval = MAX_SEND_INTERVAL;
1009 } 1041 }
1010 else 1042 else
1011 { 1043 {
1012#if 1 1044#if 0
1013 dns->send_interval *= 0.999; 1045 dns->send_interval *= 0.999;
1014#endif 1046#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 1047 // the latency surely puts an upper bound on
1019 // the minimum send interval 1048 // the minimum send interval
1020 double latency = NOW - (*i)->sent; 1049 double latency = ev_now () - (*i)->sent;
1050
1051 if (latency < dns->min_latency)
1021 dns->last_latency = latency; 1052 dns->min_latency = latency;
1022 1053
1023 if (dns->send_interval > latency) 1054 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1055 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1056
1057 if (dns->send_interval < conf.dns_send_interval)
1024 dns->send_interval = latency; 1058 dns->send_interval = conf.dns_send_interval;
1025 } 1059 }
1026 1060
1027 delete *i; 1061 delete *i;
1028 dns_sndpq.erase (i); 1062 dns_sndpq.erase (i);
1029 1063
… …
1134 break; 1168 break;
1135 } 1169 }
1136} 1170}
1137 1171
1138void 1172void
1139vpn::dnsv4_ev (io_watcher &w, short revents) 1173vpn::dnsv4_ev (ev::io &w, int revents)
1140{ 1174{
1141 if (revents & EVENT_READ) 1175 if (revents & EV_READ)
1142 { 1176 {
1143 dns_packet *pkt = new dns_packet; 1177 dns_packet *pkt = new dns_packet;
1144 struct sockaddr_in sa; 1178 struct sockaddr_in sa;
1145 socklen_t sa_len = sizeof (sa); 1179 socklen_t sa_len = sizeof (sa);
1146 1180
1147 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1181 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1148 1182
1149 if (pkt->len > 0) 1183 if (pkt->len > 0)
1150 { 1184 {
1151 if (THISNODE->dns_port) 1185 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1186 dnsv4_client (*pkt);
1187 else
1152 { 1188 {
1153 dnsv4_server (*pkt); 1189 dnsv4_server (*pkt);
1154 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1190 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1155 } 1191 }
1156 else
1157 dnsv4_client (*pkt);
1158 1192
1159 delete pkt; 1193 delete pkt;
1160 } 1194 }
1161 } 1195 }
1162} 1196}
1163 1197
1164bool 1198bool
1165vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1199vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1166{ 1200{
1167 int client = ntohs (si.port); 1201 int client = ntohl (si.host);
1168 1202
1169 assert (0 < client && client <= conns.size ()); 1203 assert (0 < client && client <= conns.size ());
1170 1204
1171 connection *c = conns [client - 1]; 1205 connection *c = conns [client - 1];
1172 1206
1173 if (!c->dns) 1207 if (!c->dns)
1174 c->dns = new dns_connection (c); 1208 c->dns = new dns_connection (c);
1175 1209
1176 if (!c->dns->snddq.put (pkt)) 1210 if (c->dns->snddq.put (pkt))
1177 return false;
1178
1179 c->dns->tw.trigger (); 1211 c->dns->tw ();
1180 1212
1213 // always return true even if the buffer overflows
1181 return true; 1214 return true;
1182} 1215}
1183 1216
1184void 1217void
1185connection::dnsv4_reset_connection () 1218connection::dnsv4_reset_connection ()
… …
1188} 1221}
1189 1222
1190#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1223#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1191 1224
1192void 1225void
1193dns_connection::time_cb (time_watcher &w) 1226dns_connection::time_cb (ev::timer &w, int revents)
1194{ 1227{
1195 // servers have to be polled 1228 // servers have to be polled
1196 if (THISNODE->dns_port) 1229 if (THISNODE->dns_port)
1197 return; 1230 return;
1198 1231
1199 // check for timeouts and (re)transmit 1232 // check for timeouts and (re)transmit
1200 tstamp next = NOW + poll_interval; 1233 tstamp next = ev::now () + poll_interval;
1201 dns_snd *send = 0; 1234 dns_snd *send = 0;
1202 1235
1203 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1236 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1204 i != vpn->dns_sndpq.end (); 1237 i != vpn->dns_sndpq.end ();
1205 ++i) 1238 ++i)
1206 { 1239 {
1207 dns_snd *r = *i; 1240 dns_snd *r = *i;
1208 1241
1209 if (r->timeout <= NOW) 1242 if (r->timeout <= ev_now ())
1210 { 1243 {
1211 if (!send) 1244 if (!send)
1212 { 1245 {
1213 send = r; 1246 send = r;
1214 1247
1215 r->retry++; 1248 r->retry++;
1216 r->timeout = NOW + (r->retry * last_latency * 8.); 1249 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1250 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1217 1251
1218 // the following code changes the query section a bit, forcing 1252 // the following code changes the query section a bit, forcing
1219 // the forwarder to generate a new request 1253 // the forwarder to generate a new request
1220 if (r->stdhdr) 1254 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); 1255 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1224 }
1225 } 1256 }
1226 } 1257 }
1227 else 1258 else
1228 NEXT (r->timeout); 1259 NEXT (r->timeout);
1229 } 1260 }
1230 1261
1231 if (last_sent + send_interval <= NOW)
1232 {
1233 if (!send) 1262 if (!send)
1263 {
1264 // generate a new packet, if wise
1265
1266 if (!established)
1234 { 1267 {
1235 // generate a new packet, if wise 1268 if (vpn->dns_sndpq.empty ())
1236
1237 if (!established)
1238 { 1269 {
1239 if (vpn->dns_sndpq.empty ())
1240 {
1241 send = new dns_snd (this); 1270 send = new dns_snd (this);
1242 1271
1243 printf ("new conn %p %d\n", this, c->conf->id);//D
1244 cfg.reset (THISNODE->id); 1272 cfg.reset (THISNODE->id);
1245 send->gen_syn_req (); 1273 send->gen_syn_req ();
1246 }
1247 } 1274 }
1248 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1275 }
1276 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1249 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1277 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1278 {
1279 if (last_sent + send_interval <= ev_now ())
1250 { 1280 {
1251 //printf ("sending data request etc.\n"); //D 1281 //printf ("sending data request etc.\n"); //D
1252 if (!snddq.empty ()) 1282 if (!snddq.empty () || last_received + 1. > ev_now ())
1253 { 1283 {
1254 poll_interval = send_interval; 1284 poll_interval = send_interval;
1255 NEXT (NOW + send_interval); 1285 NEXT (ev_now () + send_interval);
1256 } 1286 }
1257 1287
1258 send = new dns_snd (this); 1288 send = new dns_snd (this);
1259 send->gen_stream_req (sndseq, snddq); 1289 send->gen_stream_req (sndseq, snddq);
1260 send->timeout = NOW + last_latency * 8.; 1290 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1291 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1261 1292
1262 sndseq = (sndseq + 1) & SEQNO_MASK; 1293 sndseq = (sndseq + 1) & SEQNO_MASK;
1263 } 1294 }
1264 1295 else
1265 if (send) 1296 NEXT (last_sent + send_interval);
1266 vpn->dns_sndpq.push_back (send);
1267 } 1297 }
1268 1298
1269 if (send) 1299 if (send)
1270 { 1300 vpn->dns_sndpq.push_back (send);
1271 last_sent = NOW; 1301 }
1302
1303 if (send)
1304 {
1305 last_sent = ev_now ();
1272 sendto (vpn->dnsv4_fd, 1306 sendto (vpn->dnsv4_fd,
1273 send->pkt->at (0), send->pkt->len, 0, 1307 send->pkt->at (0), send->pkt->len, 0,
1274 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1308 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1275 }
1276 } 1309 }
1277 else
1278 NEXT (last_sent + send_interval);
1279 1310
1280 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1311 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1281 poll_interval, send_interval, next - NOW, 1312 poll_interval, send_interval, next - ev_now (),
1282 vpn->dns_sndpq.size (), snddq.size ()); 1313 vpn->dns_sndpq.size (), snddq.size (),
1314 rcvpq.size ());
1283 1315
1284 // TODO: no idea when this happens, but when next < NOW, we have a problem 1316 // TODO: no idea when this happens, but when next < ev_now (), we have a problem
1317 // doesn't seem to happen anymore
1285 if (next < NOW + 0.0001) 1318 if (next < ev_now () + 0.001)
1286 next = NOW + 0.1; 1319 next = ev_now () + 0.1;
1287 1320
1288 w.start (next); 1321 w.start (next - ev_now ());
1289} 1322}
1290 1323
1291#endif 1324#endif
1292 1325

Diff Legend

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