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 1.19 by pcg, Sun Mar 6 18:34:46 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
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 40// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27// it's a hack, use only in emergency situations please. 41// it's a hack, use only in emergency situations please.
28 42
29#include <cstring> 43#include <cstring>
44#include <cassert>
30 45
31#include <sys/types.h> 46#include <sys/types.h>
32#include <sys/socket.h> 47#include <sys/socket.h>
33#include <sys/wait.h> 48#include <sys/wait.h>
34#include <sys/uio.h> 49#include <sys/uio.h>
… …
37#include <unistd.h> 52#include <unistd.h>
38#include <fcntl.h> 53#include <fcntl.h>
39 54
40#include <map> 55#include <map>
41 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
42#include <gmp.h> 58#include <gmp.h>
43 59
44#include "netcompat.h" 60#include "netcompat.h"
45 61
46#include "vpn.h" 62#include "vpn.h"
47 63
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 64#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
50#define ACTIVITY_INTERVAL 5. 65#define ACTIVITY_INTERVAL 5.
51 66
52#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
53#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54 69
55#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
56#define MAX_SEND_INTERVAL 0.5 // optimistic? 70#define MAX_SEND_INTERVAL 2. // optimistic?
57 71
58#define MAX_OUTSTANDING 10 // max. outstanding requests
59#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#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 73#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
61 74
62#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
63// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
64// every two request bytes less give room for one reply byte 77// every request byte less give room for two reply bytes
65 78
66#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
67#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
68 81
69#define MAX_LBL_SIZE 63 82#define MAX_LBL_SIZE 63
… …
264static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 277static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
265 278
266///////////////////////////////////////////////////////////////////////////// 279/////////////////////////////////////////////////////////////////////////////
267 280
268#define HDRSIZE 6 281#define HDRSIZE 6
269 282
270inline 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)
271{ 284{
272 seqno &= SEQNO_MASK; 285 seqno &= SEQNO_MASK;
273 286
274 u8 hdr[3] = { 287 u8 hdr[3] = {
… …
408struct dns_cfg 421struct dns_cfg
409{ 422{
410 static int next_uid; 423 static int next_uid;
411 424
412 u8 id1, id2, id3, id4; 425 u8 id1, id2, id3, id4;
426
413 u8 version; 427 u8 version;
428 u8 flags;
414 u8 rrtype; 429 u8 rrtype;
415 u8 flags;
416 u8 def_ttl; 430 u8 def_ttl;
417 u8 rcv_cdc; 431
418 u8 snd_cdc;
419 u16 max_size;
420 u16 client; 432 u16 client;
421 u16 uid; // to make request unique 433 u16 uid; // to make request unique
422 434
423 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;
424 444
425 void reset (int clientid); 445 void reset (int clientid);
426 bool valid (); 446 bool valid ();
427}; 447};
428 448
… …
437 457
438 version = 1; 458 version = 1;
439 459
440 rrtype = RR_TYPE_TXT; 460 rrtype = RR_TYPE_TXT;
441 flags = 0; 461 flags = 0;
442 def_ttl = 1; 462 def_ttl = 0;
463 seq_cdc = 26;
464 req_cdc = 62;
443 rcv_cdc = 0; 465 rep_cdc = 0;
444 snd_cdc = 62;
445 max_size = ntohs (MAX_PKT_SIZE); 466 max_size = htons (MAX_PKT_SIZE);
446 client = ntohs (clientid); 467 client = htons (clientid);
447 uid = next_uid++; 468 uid = next_uid++;
469 delay = 0;
448 470
449 memset (reserved, 0, 8); 471 r3 = r4 = 0;
472 r4 = r5 = r6 = r7 = 0;
450} 473}
451 474
452bool dns_cfg::valid () 475bool dns_cfg::valid ()
453{ 476{
477 // although the protocol itself allows for some configurability,
478 // only the following encoding/decoding settings are implemented.
454 return id1 == 'G' 479 return id1 == 'G'
455 && id2 == 'V' 480 && id2 == 'V'
456 && id3 == 'P' 481 && id3 == 'P'
457 && id4 == 'E' 482 && id4 == 'E'
483 && seq_cdc == 26
484 && req_cdc == 62
485 && rep_cdc == 0
458 && version == 1 486 && version == 1;
459 && flags == 0
460 && rcv_cdc == 0
461 && snd_cdc == 62
462 && max_size == ntohs (MAX_PKT_SIZE);
463} 487}
464 488
465struct dns_packet : net_packet 489struct dns_packet : net_packet
466{ 490{
467 u16 id; 491 u16 id;
468 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
469 u16 qdcount, ancount, nscount, arcount; 493 u16 qdcount, ancount, nscount, arcount;
470 494
471 u8 data[MAXSIZE - 6 * 2]; 495 u8 data [MAXSIZE - 6 * 2];
472 496
473 int decode_label (char *data, int size, int &offs); 497 int decode_label (char *data, int size, int &offs);
474}; 498};
475 499
476int dns_packet::decode_label (char *data, int size, int &offs) 500int dns_packet::decode_label (char *data, int size, int &offs)
… …
538 562
539 bool established; 563 bool established;
540 564
541 tstamp last_received; 565 tstamp last_received;
542 tstamp last_sent; 566 tstamp last_sent;
543 double last_latency; 567 double min_latency;
544 double poll_interval, send_interval; 568 double poll_interval, send_interval;
545 569
546 vector<dns_rcv *> rcvpq; 570 vector<dns_rcv *> rcvpq;
547 571
548 byte_stream rcvdq; int rcvseq; 572 byte_stream rcvdq; int rcvseq; int repseq;
549 byte_stream snddq; int sndseq; 573 byte_stream snddq; int sndseq;
550 574
551 void time_cb (time_watcher &w); time_watcher tw; 575 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
552 void receive_rep (dns_rcv *r); 576 void receive_rep (dns_rcv *r);
553 577
554 dns_connection (connection *c); 578 dns_connection (connection *c);
555 ~dns_connection (); 579 ~dns_connection ();
556}; 580};
… …
575: dns (dns) 599: dns (dns)
576{ 600{
577 timeout = 0; 601 timeout = 0;
578 retry = 0; 602 retry = 0;
579 seqno = 0; 603 seqno = 0;
580 sent = NOW; 604 sent = ev_now ();
581 stdhdr = false; 605 stdhdr = false;
582 606
583 pkt = new dns_packet; 607 pkt = new dns_packet;
584 608
585 pkt->id = next_id (); 609 pkt->id = next_id ();
… …
616void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 640void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
617{ 641{
618 stdhdr = true; 642 stdhdr = true;
619 this->seqno = seqno; 643 this->seqno = seqno;
620 644
621 timeout = NOW + INITIAL_TIMEOUT; 645 timeout = ev_now () + INITIAL_TIMEOUT;
622 646
623 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 647 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
624 pkt->qdcount = htons (1); 648 pkt->qdcount = htons (1);
625 649
626 int offs = 6*2; 650 int offs = 6*2;
… …
661 pkt->len = offs; 685 pkt->len = offs;
662} 686}
663 687
664void dns_snd::gen_syn_req () 688void dns_snd::gen_syn_req ()
665{ 689{
666 timeout = NOW + INITIAL_SYN_TIMEOUT; 690 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
667
668 printf ("send syn\n");//D
669 691
670 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 692 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
671 pkt->qdcount = htons (1); 693 pkt->qdcount = htons (1);
672 694
673 int offs = 6 * 2; 695 int offs = 6 * 2;
… …
712///////////////////////////////////////////////////////////////////////////// 734/////////////////////////////////////////////////////////////////////////////
713 735
714dns_connection::dns_connection (connection *c) 736dns_connection::dns_connection (connection *c)
715: c (c) 737: c (c)
716, rcvdq (MAX_BACKLOG * 2) 738, rcvdq (MAX_BACKLOG * 2)
717, snddq (MAX_BACKLOG * 2) 739, snddq (MAX_BACKLOG)
718, tw (this, &dns_connection::time_cb)
719{ 740{
741 tw.set<dns_connection, &dns_connection::time_cb> (this);
742
720 vpn = c->vpn; 743 vpn = c->vpn;
721 744
722 established = false; 745 established = false;
723 746
724 rcvseq = sndseq = 0; 747 rcvseq = repseq = sndseq = 0;
725 748
726 last_sent = last_received = 0; 749 last_sent = last_received = 0;
727 poll_interval = MIN_POLL_INTERVAL; 750 poll_interval = 0.5; // starting here
728 send_interval = 0.5; // starting rate 751 send_interval = 0.5; // starting rate
729 last_latency = INITIAL_TIMEOUT; 752 min_latency = INITIAL_TIMEOUT;
730} 753}
731 754
732dns_connection::~dns_connection () 755dns_connection::~dns_connection ()
733{ 756{
734 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 757 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
… …
739 762
740void dns_connection::receive_rep (dns_rcv *r) 763void dns_connection::receive_rep (dns_rcv *r)
741{ 764{
742 if (r->datalen) 765 if (r->datalen)
743 { 766 {
744 last_received = NOW; 767 last_received = ev_now ();
745 tw.trigger (); 768 tw ();
746 769
747 poll_interval = send_interval; 770 poll_interval = send_interval;
748 } 771 }
749 else 772 else
750 { 773 {
751 poll_interval *= 1.5; 774 poll_interval *= 1.5;
775
752 if (poll_interval > MAX_POLL_INTERVAL) 776 if (poll_interval > MAX_POLL_INTERVAL)
753 poll_interval = MAX_POLL_INTERVAL; 777 poll_interval = MAX_POLL_INTERVAL;
754 } 778 }
755 779
756 rcvpq.push_back (r); 780 rcvpq.push_back (r);
… …
759 783
760 // find next packet 784 // find next packet
761 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 785 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
762 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 786 if (SEQNO_EQ (rcvseq, (*i)->seqno))
763 { 787 {
788 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
764 // enter the packet into our input stream 789 // enter the packet into our input stream
765 r = *i; 790 r = *i;
766 791
767 // remove the oldest packet, look forward, as it's oldest first 792 // remove the oldest packet, look forward, as it's oldest first
768 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)
769 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 794 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
770 { 795 {
796 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
771 delete *j; 797 delete *j;
772 rcvpq.erase (j); 798 rcvpq.erase (j);
773 break; 799 break;
774 } 800 }
775 801
… …
782 } 808 }
783 809
784 while (vpn_packet *pkt = rcvdq.get ()) 810 while (vpn_packet *pkt = rcvdq.get ())
785 { 811 {
786 sockinfo si; 812 sockinfo si;
787 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;
788 814
789 vpn->recv_vpn_packet (pkt, si); 815 vpn->recv_vpn_packet (pkt, si);
790 816
791 delete pkt; 817 delete pkt;
792 } 818 }
… …
806 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 832 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
807 833
808 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 834 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
809 && pkt.qdcount == htons (1)) 835 && pkt.qdcount == htons (1))
810 { 836 {
811 char qname[MAXSIZE]; 837 char qname [MAXSIZE];
812 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 838 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
813 839
814 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 840 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
815 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 841 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
816 842
… …
823 849
824 int dlen = strlen (THISNODE->domain); 850 int dlen = strlen (THISNODE->domain);
825 851
826 if (qclass == RR_CLASS_IN 852 if (qclass == RR_CLASS_IN
827 && qlen > dlen + 1 853 && qlen > dlen + 1
828 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 854 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
829 { 855 {
830 // now generate reply 856 // now generate reply
831 pkt.ancount = htons (1); // one answer RR 857 pkt.ancount = htons (1); // one answer RR
832 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 858 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
833 859
… …
846 if (0 < client && client <= conns.size ()) 872 if (0 < client && client <= conns.size ())
847 { 873 {
848 connection *c = conns [client - 1]; 874 connection *c = conns [client - 1];
849 dns_connection *dns = c->dns; 875 dns_connection *dns = c->dns;
850 dns_rcv *rcv; 876 dns_rcv *rcv;
851 bool in_seq;
852 877
853 if (dns) 878 if (dns)
854 { 879 {
855 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 (); )
856 if (SEQNO_EQ ((*i)->seqno, seqno)) 881 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
867 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);
868 893
869 goto duplicate_request; 894 goto duplicate_request;
870 } 895 }
871 896
872 in_seq = dns->rcvseq == seqno;
873
874 // new packet, queue 897 // new packet, queue
875 rcv = new dns_rcv (seqno, data, datalen); 898 rcv = new dns_rcv (seqno, data, datalen);
876 dns->receive_rep (rcv); 899 dns->receive_rep (rcv);
877 } 900 }
878 901
902 {
879 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
880 904
881 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 905 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
882 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 906 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
883 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
884 pkt [offs++] = 0; pkt [offs++] = 0; 908 pkt [offs++] = 0; pkt [offs++] = 0;
885 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
886 910
887 int rdlen_offs = offs += 2; 911 int rdlen_offs = offs += 2;
888 912
913 if (dns)
914 {
889 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 915 int dlen = ntohs (dns->cfg.max_size) - offs;
916
890 // 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
891 dlen -= qlen; 918 dlen -= qlen;
892 919
893 if (dns)
894 {
895 // only put data into in-order sequence packets, if 920 // only put data into in-order sequence packets, if
896 // we receive out-of-order packets we generate empty 921 // we receive out-of-order packets we generate empty
897 // replies 922 // replies
898 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)
899 { 925 {
926 dns->repseq = seqno;
927
928 while (dlen > 1 && !dns->snddq.empty ())
929 {
900 int txtlen = dlen <= 255 ? dlen - 1 : 255; 930 int txtlen = dlen <= 255 ? dlen - 1 : 255;
901 931
902 if (txtlen > dns->snddq.size ()) 932 if (txtlen > dns->snddq.size ())
903 txtlen = dns->snddq.size (); 933 txtlen = dns->snddq.size ();
904 934
905 pkt[offs++] = txtlen; 935 pkt[offs++] = txtlen;
906 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 936 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
907 offs += txtlen; 937 offs += txtlen;
908 dns->snddq.remove (txtlen); 938 dns->snddq.remove (txtlen);
909 939
910 dlen -= txtlen + 1; 940 dlen -= txtlen + 1;
941 }
911 } 942 }
912 943
913 // avoid empty TXT rdata 944 // avoid completely empty TXT rdata
914 if (offs == rdlen_offs) 945 if (offs == rdlen_offs)
915 pkt[offs++] = 0; 946 pkt[offs++] = 0;
916 947
917 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 948 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
918 } 949 }
919 else 950 else
920 { 951 {
921 // send RST 952 // send RST
922 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;
923 pkt [offs++] = CMD_IP_RST; 954 pkt [offs++] = CMD_IP_RST;
924 } 955 }
925 956
926 int rdlen = offs - rdlen_offs; 957 int rdlen = offs - rdlen_offs;
927 958
928 pkt [rdlen_offs - 2] = rdlen >> 8; 959 pkt [rdlen_offs - 2] = rdlen >> 8;
929 pkt [rdlen_offs - 1] = rdlen; 960 pkt [rdlen_offs - 1] = rdlen;
930 961
931 if (dns) 962 if (dns)
932 { 963 {
933 // now update dns_rcv copy 964 // now update dns_rcv copy
934 rcv->pkt->len = offs; 965 rcv->pkt->len = offs;
935 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 966 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
936 } 967 }
968 }
937 969
938 duplicate_request: ; 970 duplicate_request: ;
939 } 971 }
940 else 972 else
941 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 973 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
953 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
954 pkt [offs++] = 0; pkt [offs++] = 0; 986 pkt [offs++] = 0; pkt [offs++] = 0;
955 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 987 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
956 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 988 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
957 989
958 slog (L_INFO, _("DNS: client %d tries to connect"), client); 990 slog (L_INFO, _("DNS: client %d connects"), client);
959 991
960 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;
961 pkt [offs++] = CMD_IP_REJ; 993 pkt [offs++] = CMD_IP_REJ;
962 994
963 if (0 < client && client <= conns.size ()) 995 if (0 < client && client <= conns.size ())
… …
997 { 1029 {
998 dns_connection *dns = (*i)->dns; 1030 dns_connection *dns = (*i)->dns;
999 connection *c = dns->c; 1031 connection *c = dns->c;
1000 int seqno = (*i)->seqno; 1032 int seqno = (*i)->seqno;
1001 u8 data[MAXSIZE], *datap = data; 1033 u8 data[MAXSIZE], *datap = data;
1034 //printf ("rcv pkt %x\n", seqno);//D
1002 1035
1003 if ((*i)->retry) 1036 if ((*i)->retry)
1004 { 1037 {
1005 dns->send_interval *= 1.01; 1038 dns->send_interval *= 1.01;
1006 if (dns->send_interval > MAX_SEND_INTERVAL) 1039 if (dns->send_interval > MAX_SEND_INTERVAL)
1007 dns->send_interval = MAX_SEND_INTERVAL; 1040 dns->send_interval = MAX_SEND_INTERVAL;
1008 } 1041 }
1009 else 1042 else
1010 { 1043 {
1011#if 1 1044#if 0
1012 dns->send_interval *= 0.999; 1045 dns->send_interval *= 0.999;
1013#endif 1046#endif
1014 if (dns->send_interval < MIN_SEND_INTERVAL)
1015 dns->send_interval = MIN_SEND_INTERVAL;
1016
1017 // the latency surely puts an upper bound on 1047 // the latency surely puts an upper bound on
1018 // the minimum send interval 1048 // the minimum send interval
1019 double latency = NOW - (*i)->sent; 1049 double latency = ev_now () - (*i)->sent;
1050
1051 if (latency < dns->min_latency)
1020 dns->last_latency = latency; 1052 dns->min_latency = latency;
1021 1053
1022 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)
1023 dns->send_interval = latency; 1058 dns->send_interval = conf.dns_send_interval;
1024 } 1059 }
1025 1060
1026 delete *i; 1061 delete *i;
1027 dns_sndpq.erase (i); 1062 dns_sndpq.erase (i);
1028 1063
… …
1133 break; 1168 break;
1134 } 1169 }
1135} 1170}
1136 1171
1137void 1172void
1138vpn::dnsv4_ev (io_watcher &w, short revents) 1173vpn::dnsv4_ev (ev::io &w, int revents)
1139{ 1174{
1140 if (revents & EVENT_READ) 1175 if (revents & EV_READ)
1141 { 1176 {
1142 dns_packet *pkt = new dns_packet; 1177 dns_packet *pkt = new dns_packet;
1143 struct sockaddr_in sa; 1178 struct sockaddr_in sa;
1144 socklen_t sa_len = sizeof (sa); 1179 socklen_t sa_len = sizeof (sa);
1145 1180
1146 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);
1147 1182
1148 if (pkt->len > 0) 1183 if (pkt->len > 0)
1149 { 1184 {
1150 if (THISNODE->dns_port) 1185 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1186 dnsv4_client (*pkt);
1187 else
1151 { 1188 {
1152 dnsv4_server (*pkt); 1189 dnsv4_server (*pkt);
1153 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);
1154 } 1191 }
1155 else
1156 dnsv4_client (*pkt);
1157 1192
1158 delete pkt; 1193 delete pkt;
1159 } 1194 }
1160 } 1195 }
1161} 1196}
1162 1197
1163bool 1198bool
1164vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1199vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1165{ 1200{
1166 int client = ntohs (si.port); 1201 int client = ntohl (si.host);
1167 1202
1168 assert (0 < client && client <= conns.size ()); 1203 assert (0 < client && client <= conns.size ());
1169 1204
1170 connection *c = conns [client - 1]; 1205 connection *c = conns [client - 1];
1171 1206
1172 if (!c->dns) 1207 if (!c->dns)
1173 c->dns = new dns_connection (c); 1208 c->dns = new dns_connection (c);
1174 1209
1175 if (!c->dns->snddq.put (pkt)) 1210 if (c->dns->snddq.put (pkt))
1176 return false;
1177
1178 c->dns->tw.trigger (); 1211 c->dns->tw ();
1179 1212
1213 // always return true even if the buffer overflows
1180 return true; 1214 return true;
1181} 1215}
1182 1216
1183void 1217void
1184connection::dnsv4_reset_connection () 1218connection::dnsv4_reset_connection ()
… …
1187} 1221}
1188 1222
1189#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1223#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1190 1224
1191void 1225void
1192dns_connection::time_cb (time_watcher &w) 1226dns_connection::time_cb (ev::timer &w, int revents)
1193{ 1227{
1194 // servers have to be polled 1228 // servers have to be polled
1195 if (THISNODE->dns_port) 1229 if (THISNODE->dns_port)
1196 return; 1230 return;
1197 1231
1198 // check for timeouts and (re)transmit 1232 // check for timeouts and (re)transmit
1199 tstamp next = NOW + poll_interval; 1233 tstamp next = ev::now () + poll_interval;
1200 dns_snd *send = 0; 1234 dns_snd *send = 0;
1201 1235
1202 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1236 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1203 i != vpn->dns_sndpq.end (); 1237 i != vpn->dns_sndpq.end ();
1204 ++i) 1238 ++i)
1205 { 1239 {
1206 dns_snd *r = *i; 1240 dns_snd *r = *i;
1207 1241
1208 if (r->timeout <= NOW) 1242 if (r->timeout <= ev_now ())
1209 { 1243 {
1210 if (!send) 1244 if (!send)
1211 { 1245 {
1212 send = r; 1246 send = r;
1213 1247
1214 r->retry++; 1248 r->retry++;
1215 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
1216 1251
1217 // the following code changes the query section a bit, forcing 1252 // the following code changes the query section a bit, forcing
1218 // the forwarder to generate a new request 1253 // the forwarder to generate a new request
1219 if (r->stdhdr) 1254 if (r->stdhdr)
1220 {
1221 //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);
1222 //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);
1223 }
1224 } 1256 }
1225 } 1257 }
1226 else 1258 else
1227 NEXT (r->timeout); 1259 NEXT (r->timeout);
1228 } 1260 }
1229 1261
1230 if (last_sent + send_interval <= NOW)
1231 {
1232 if (!send) 1262 if (!send)
1263 {
1264 // generate a new packet, if wise
1265
1266 if (!established)
1233 { 1267 {
1234 // generate a new packet, if wise 1268 if (vpn->dns_sndpq.empty ())
1235
1236 if (!established)
1237 { 1269 {
1238 if (vpn->dns_sndpq.empty ())
1239 {
1240 send = new dns_snd (this); 1270 send = new dns_snd (this);
1241 1271
1242 printf ("new conn %p %d\n", this, c->conf->id);//D
1243 cfg.reset (THISNODE->id); 1272 cfg.reset (THISNODE->id);
1244 send->gen_syn_req (); 1273 send->gen_syn_req ();
1245 }
1246 } 1274 }
1247 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1275 }
1276 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1248 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1277 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1278 {
1279 if (last_sent + send_interval <= ev_now ())
1249 { 1280 {
1250 //printf ("sending data request etc.\n"); //D 1281 //printf ("sending data request etc.\n"); //D
1251 if (!snddq.empty ()) 1282 if (!snddq.empty () || last_received + 1. > ev_now ())
1252 { 1283 {
1253 poll_interval = send_interval; 1284 poll_interval = send_interval;
1254 NEXT (NOW + send_interval); 1285 NEXT (ev_now () + send_interval);
1255 } 1286 }
1256 1287
1257 send = new dns_snd (this); 1288 send = new dns_snd (this);
1258 send->gen_stream_req (sndseq, snddq); 1289 send->gen_stream_req (sndseq, snddq);
1259 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
1260 1292
1261 sndseq = (sndseq + 1) & SEQNO_MASK; 1293 sndseq = (sndseq + 1) & SEQNO_MASK;
1262 } 1294 }
1263 1295 else
1264 if (send) 1296 NEXT (last_sent + send_interval);
1265 vpn->dns_sndpq.push_back (send);
1266 } 1297 }
1267 1298
1268 if (send) 1299 if (send)
1269 { 1300 vpn->dns_sndpq.push_back (send);
1270 last_sent = NOW; 1301 }
1302
1303 if (send)
1304 {
1305 last_sent = ev_now ();
1271 sendto (vpn->dnsv4_fd, 1306 sendto (vpn->dnsv4_fd,
1272 send->pkt->at (0), send->pkt->len, 0, 1307 send->pkt->at (0), send->pkt->len, 0,
1273 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1308 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1274 }
1275 } 1309 }
1276 else
1277 NEXT (last_sent + send_interval);
1278 1310
1279 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)",
1280 poll_interval, send_interval, next - NOW, 1312 poll_interval, send_interval, next - ev_now (),
1281 vpn->dns_sndpq.size (), snddq.size ()); 1313 vpn->dns_sndpq.size (), snddq.size (),
1314 rcvpq.size ());
1282 1315
1283 // 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
1284 if (next < NOW + 0.0001) 1318 if (next < ev_now () + 0.001)
1285 next = NOW + 0.1; 1319 next = ev_now () + 0.1;
1286 1320
1287 w.start (next); 1321 w.start (next - ev_now ());
1288} 1322}
1289 1323
1290#endif 1324#endif
1291 1325

Diff Legend

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