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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.24 by pcg, Mon Mar 7 01:31:26 2005 UTC vs.
Revision 1.50 by root, Sun Mar 6 13:49:50 2011 UTC

1/* 1/*
2 vpn_dns.C -- handle the dns tunnel part of the protocol. 2 vpn_dns.C -- handle the dns tunnel part of the protocol.
3 Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de> 3 Copyright (C) 2003-2008 Marc Lehmann <gvpe@schmorp.de>
4 4
5 This file is part of GVPE. 5 This file is part of GVPE.
6 6
7 GVPE is free software; you can redistribute it and/or modify 7 GVPE is free software; you can redistribute it and/or modify it
8 it under the terms of the GNU General Public License as published by 8 under the terms of the GNU General Public License as published by the
9 the Free Software Foundation; either version 2 of the License, or 9 Free Software Foundation; either version 3 of the License, or (at your
10 (at your option) any later version. 10 option) any later version.
11 11
12 This program is distributed in the hope that it will be useful, 12 This program is distributed in the hope that it will be useful, but
13 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15 GNU General Public License for more details. 15 Public License for more details.
16 16
17 You should have received a copy of the GNU General Public License 17 You should have received a copy of the GNU General Public License along
18 along with gvpe; if not, write to the Free Software 18 with this program; if not, see <http://www.gnu.org/licenses/>.
19 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19
20 Additional permission under GNU GPL version 3 section 7
21
22 If you modify this Program, or any covered work, by linking or
23 combining it with the OpenSSL project's OpenSSL library (or a modified
24 version of that library), containing parts covered by the terms of the
25 OpenSSL or SSLeay licenses, the licensors of this Program grant you
26 additional permission to convey the resulting work. Corresponding
27 Source for a non-source form of such a combination shall include the
28 source code for the parts of OpenSSL used as well as that of the
29 covered work.
20*/ 30*/
31
32// TODO: EDNS0 option to increase dns mtu?
33// TODO: re-write dns packet parsing/creation using a safe mem-buffer
34// to ensure no buffer overflows or similar problems.
21 35
22#include "config.h" 36#include "config.h"
23 37
24#if ENABLE_DNS 38#if ENABLE_DNS
25 39
… …
38#include <unistd.h> 52#include <unistd.h>
39#include <fcntl.h> 53#include <fcntl.h>
40 54
41#include <map> 55#include <map>
42 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
43#include <gmp.h> 58#include <gmp.h>
44 59
45#include "netcompat.h" 60#include "netcompat.h"
46 61
47#include "vpn.h" 62#include "vpn.h"
48 63
49#define MIN_POLL_INTERVAL .02 // how often to poll minimally when the server has data
50#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data 64#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
51#define ACTIVITY_INTERVAL 5. 65#define ACTIVITY_INTERVAL 5.
52 66
53#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
54#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
55 69
56#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
57#define MAX_SEND_INTERVAL 0.5 // optimistic? 70#define MAX_SEND_INTERVAL 2. // optimistic?
58 71
59#define MAX_OUTSTANDING 10 // max. outstanding requests
60#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
61#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE 73#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
62 74
63#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well 75#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well
64// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
65// every two request bytes less give room for one reply byte 77// every request byte less give room for two reply bytes
66 78
67#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
68#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
69 81
70#define MAX_LBL_SIZE 63 82#define MAX_LBL_SIZE 63
71#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
72 84
73#define RR_TYPE_A 1 85#define RR_TYPE_A 1
74#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
75#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
76#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
77 90
78#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
79 92
80#define CMD_IP_1 207 93#define CMD_IP_1 207
… …
104 memset (enc, (char) 0, 256); 117 memset (enc, (char) 0, 256);
105 memset (dec, (char)INVALID, 256); 118 memset (dec, (char)INVALID, 256);
106 119
107 for (size = 0; cmap [size]; size++) 120 for (size = 0; cmap [size]; size++)
108 { 121 {
122 char c = cmap [size];
123
109 enc [size] = cmap [size]; 124 enc [size] = c;
110 dec [(u8)enc [size]] = size; 125 dec [(u8)c] = size;
126
127 // allow lowercase/uppercase aliases if possible
128 if (c >= 'A' && c <= 'Z' && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size;
129 if (c >= 'a' && c <= 'z' && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size;
111 } 130 }
112 131
113 assert (size < 256); 132 assert (size < 256);
114} 133}
115 134
… …
155 enc_len [len] = n; 174 enc_len [len] = n;
156 dec_len [n] = len; 175 dec_len [n] = len;
157 } 176 }
158} 177}
159 178
179unsigned int
160unsigned int basecoder::encode_len (unsigned int len) 180basecoder::encode_len (unsigned int len)
161{ 181{
162 return enc_len [len]; 182 return enc_len [len];
163} 183}
164 184
185unsigned int
165unsigned int basecoder::decode_len (unsigned int len) 186basecoder::decode_len (unsigned int len)
166{ 187{
167 while (len && !dec_len [len]) 188 while (len && !dec_len [len])
168 --len; 189 --len;
169 190
170 return dec_len [len]; 191 return dec_len [len];
171} 192}
172 193
194unsigned int
173unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 195basecoder::encode (char *dst, u8 *src, unsigned int len)
174{ 196{
175 if (!len || len > MAX_DEC_LEN) 197 if (!len || len > MAX_DEC_LEN)
176 return 0; 198 return 0;
177 199
178 int elen = encode_len (len); 200 int elen = encode_len (len);
… …
197 *dst++ = cmap.encode [dst_ [i]]; 219 *dst++ = cmap.encode [dst_ [i]];
198 220
199 return elen; 221 return elen;
200} 222}
201 223
224unsigned int
202unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 225basecoder::decode (u8 *dst, char *src, unsigned int len)
203{ 226{
204 if (!len || len > MAX_ENC_LEN) 227 if (!len || len > MAX_ENC_LEN)
205 return 0; 228 return 0;
206 229
207 u8 src_ [MAX_ENC_LEN]; 230 u8 src_ [MAX_ENC_LEN];
… …
266 289
267///////////////////////////////////////////////////////////////////////////// 290/////////////////////////////////////////////////////////////////////////////
268 291
269#define HDRSIZE 6 292#define HDRSIZE 6
270 293
294inline void
271inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 295encode_header (char *data, int clientid, int seqno, int retry = 0)
272{ 296{
273 seqno &= SEQNO_MASK; 297 seqno &= SEQNO_MASK;
274 298
275 u8 hdr[3] = { 299 u8 hdr[3] = {
276 clientid, 300 clientid,
… …
281 assert (clientid < 256); 305 assert (clientid < 256);
282 306
283 cdc26.encode (data, hdr, 3); 307 cdc26.encode (data, hdr, 3);
284} 308}
285 309
310inline void
286inline void decode_header (char *data, int &clientid, int &seqno) 311decode_header (char *data, int &clientid, int &seqno)
287{ 312{
288 u8 hdr[3]; 313 u8 hdr[3];
289 314
290 cdc26.decode (hdr, data, HDRSIZE); 315 cdc26.decode (hdr, data, HDRSIZE);
291 316
… …
324byte_stream::~byte_stream () 349byte_stream::~byte_stream ()
325{ 350{
326 delete data; 351 delete data;
327} 352}
328 353
354void
329void byte_stream::remove (int count) 355byte_stream::remove (int count)
330{ 356{
331 if (count > fill) 357 if (count > fill)
332 assert (count <= fill); 358 assert (count <= fill);
333 359
334 memmove (data, data + count, fill -= count); 360 memmove (data, data + count, fill -= count);
335} 361}
336 362
363bool
337bool byte_stream::put (u8 *data, unsigned int datalen) 364byte_stream::put (u8 *data, unsigned int datalen)
338{ 365{
339 if (maxsize - fill < datalen) 366 if (maxsize - fill < datalen)
340 return false; 367 return false;
341 368
342 memcpy (this->data + fill, data, datalen); fill += datalen; 369 memcpy (this->data + fill, data, datalen); fill += datalen;
343 370
344 return true; 371 return true;
345} 372}
346 373
374bool
347bool byte_stream::put (vpn_packet *pkt) 375byte_stream::put (vpn_packet *pkt)
348{ 376{
349 if (maxsize - fill < pkt->len + 2) 377 if (maxsize - fill < pkt->len + 2)
350 return false; 378 return false;
351 379
352 data [fill++] = pkt->len >> 8; 380 data [fill++] = pkt->len >> 8;
… …
423 u16 max_size; 451 u16 max_size;
424 u8 seq_cdc; 452 u8 seq_cdc;
425 u8 req_cdc; 453 u8 req_cdc;
426 454
427 u8 rep_cdc; 455 u8 rep_cdc;
456 u8 delay; // time in 0.01s units that the server may delay replying packets
428 u8 r2, r3, r4; 457 u8 r3, r4;
429 458
430 u8 r5, r6, r7, r8; 459 u8 r5, r6, r7, r8;
431 460
432 void reset (int clientid); 461 void reset (int clientid);
433 bool valid (); 462 bool valid ();
434}; 463};
435 464
436int dns_cfg::next_uid; 465int dns_cfg::next_uid;
437 466
467void
438void dns_cfg::reset (int clientid) 468dns_cfg::reset (int clientid)
439{ 469{
440 id1 = 'G'; 470 id1 = 'G';
441 id2 = 'V'; 471 id2 = 'V';
442 id3 = 'P'; 472 id3 = 'P';
443 id4 = 'E'; 473 id4 = 'E';
… …
448 flags = 0; 478 flags = 0;
449 def_ttl = 0; 479 def_ttl = 0;
450 seq_cdc = 26; 480 seq_cdc = 26;
451 req_cdc = 62; 481 req_cdc = 62;
452 rep_cdc = 0; 482 rep_cdc = 0;
453 max_size = ntohs (MAX_PKT_SIZE); 483 max_size = htons (MAX_PKT_SIZE);
454 client = ntohs (clientid); 484 client = htons (clientid);
455 uid = next_uid++; 485 uid = next_uid++;
486 delay = 0;
456 487
457 r2 = r3 = r4 = 0; 488 r3 = r4 = 0;
458 r4 = r5 = r6 = r7 = 0; 489 r4 = r5 = r6 = r7 = 0;
459} 490}
460 491
492bool
461bool dns_cfg::valid () 493dns_cfg::valid ()
462{ 494{
495 // although the protocol itself allows for some configurability,
496 // only the following encoding/decoding settings are implemented.
463 return id1 == 'G' 497 return id1 == 'G'
464 && id2 == 'V' 498 && id2 == 'V'
465 && id3 == 'P' 499 && id3 == 'P'
466 && id4 == 'E' 500 && id4 == 'E'
467 && seq_cdc == 26 501 && seq_cdc == 26
468 && req_cdc == 62 502 && req_cdc == 62
469 && rep_cdc == 0 503 && rep_cdc == 0
470 && version == 1 504 && version == 1;
471 && max_size == ntohs (MAX_PKT_SIZE);
472} 505}
473 506
474struct dns_packet : net_packet 507struct dns_packet : net_packet
475{ 508{
476 u16 id; 509 u16 id;
… …
480 u8 data [MAXSIZE - 6 * 2]; 513 u8 data [MAXSIZE - 6 * 2];
481 514
482 int decode_label (char *data, int size, int &offs); 515 int decode_label (char *data, int size, int &offs);
483}; 516};
484 517
518int
485int dns_packet::decode_label (char *data, int size, int &offs) 519dns_packet::decode_label (char *data, int size, int &offs)
486{ 520{
487 char *orig = data; 521 char *orig = data;
488 522
489 memset (data, 0, size); 523 memset (data, 0, size);
490 524
… …
516 return data - orig; 550 return data - orig;
517} 551}
518 552
519///////////////////////////////////////////////////////////////////////////// 553/////////////////////////////////////////////////////////////////////////////
520 554
555static
556u16 next_id ()
557{
521static u16 dns_id = 0; // TODO: should be per-vpn 558 static u16 dns_id = 0; // TODO: should be per-vpn
522 559
523static u16 next_id ()
524{
525 if (!dns_id) 560 if (!dns_id)
526 dns_id = time (0); 561 dns_id = time (0);
527 562
528 // the simplest lsfr with periodicity 65535 i could find 563 // the simplest lsfr with periodicity 65535 i could find
529 dns_id = (dns_id << 1) 564 dns_id = (dns_id << 1)
… …
547 582
548 bool established; 583 bool established;
549 584
550 tstamp last_received; 585 tstamp last_received;
551 tstamp last_sent; 586 tstamp last_sent;
552 double last_latency; 587 double min_latency;
553 double poll_interval, send_interval; 588 double poll_interval, send_interval;
554 589
555 vector<dns_rcv *> rcvpq; 590 vector<dns_rcv *> rcvpq;
556 591
557 byte_stream rcvdq; int rcvseq; 592 byte_stream rcvdq; int rcvseq; int repseq;
558 byte_stream snddq; int sndseq; 593 byte_stream snddq; int sndseq;
559 594
560 void time_cb (time_watcher &w); time_watcher tw; 595 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
561 void receive_rep (dns_rcv *r); 596 void receive_rep (dns_rcv *r);
562 597
563 dns_connection (connection *c); 598 dns_connection (connection *c);
564 ~dns_connection (); 599 ~dns_connection ();
565}; 600};
… …
584: dns (dns) 619: dns (dns)
585{ 620{
586 timeout = 0; 621 timeout = 0;
587 retry = 0; 622 retry = 0;
588 seqno = 0; 623 seqno = 0;
589 sent = NOW; 624 sent = ev_now ();
590 stdhdr = false; 625 stdhdr = false;
591 626
592 pkt = new dns_packet; 627 pkt = new dns_packet;
593 628
594 pkt->id = next_id (); 629 pkt->id = next_id ();
… …
597dns_snd::~dns_snd () 632dns_snd::~dns_snd ()
598{ 633{
599 delete pkt; 634 delete pkt;
600} 635}
601 636
637static void
602static void append_domain (dns_packet &pkt, int &offs, const char *domain) 638append_domain (dns_packet &pkt, int &offs, const char *domain)
603{ 639{
604 // add tunnel domain 640 // add tunnel domain
605 for (;;) 641 for (;;)
606 { 642 {
607 const char *end = strchr (domain, '.'); 643 const char *end = strchr (domain, '.');
… …
620 656
621 domain = end + 1; 657 domain = end + 1;
622 } 658 }
623} 659}
624 660
661void
625void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 662dns_snd::gen_stream_req (int seqno, byte_stream &stream)
626{ 663{
627 stdhdr = true; 664 stdhdr = true;
628 this->seqno = seqno; 665 this->seqno = seqno;
629 666
630 timeout = NOW + INITIAL_TIMEOUT; 667 timeout = ev_now () + INITIAL_TIMEOUT;
631 668
632 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 669 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
633 pkt->qdcount = htons (1); 670 pkt->qdcount = htons (1);
634 671
635 int offs = 6*2; 672 int offs = 6*2;
… …
668 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 705 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
669 706
670 pkt->len = offs; 707 pkt->len = offs;
671} 708}
672 709
710void
673void dns_snd::gen_syn_req () 711dns_snd::gen_syn_req ()
674{ 712{
675 timeout = NOW + INITIAL_SYN_TIMEOUT; 713 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
676 714
677 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 715 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
678 pkt->qdcount = htons (1); 716 pkt->qdcount = htons (1);
679 717
680 int offs = 6 * 2; 718 int offs = 6 * 2;
… …
719///////////////////////////////////////////////////////////////////////////// 757/////////////////////////////////////////////////////////////////////////////
720 758
721dns_connection::dns_connection (connection *c) 759dns_connection::dns_connection (connection *c)
722: c (c) 760: c (c)
723, rcvdq (MAX_BACKLOG * 2) 761, rcvdq (MAX_BACKLOG * 2)
724, snddq (MAX_BACKLOG * 2) 762, snddq (MAX_BACKLOG)
725, tw (this, &dns_connection::time_cb)
726{ 763{
764 tw.set<dns_connection, &dns_connection::time_cb> (this);
765
727 vpn = c->vpn; 766 vpn = c->vpn;
728 767
729 established = false; 768 established = false;
730 769
731 rcvseq = sndseq = 0; 770 rcvseq = repseq = sndseq = 0;
732 771
733 last_sent = last_received = 0; 772 last_sent = last_received = 0;
734 poll_interval = MIN_POLL_INTERVAL; 773 poll_interval = 0.5; // starting here
735 send_interval = 0.5; // starting rate 774 send_interval = 0.5; // starting rate
736 last_latency = INITIAL_TIMEOUT; 775 min_latency = INITIAL_TIMEOUT;
737} 776}
738 777
739dns_connection::~dns_connection () 778dns_connection::~dns_connection ()
740{ 779{
741 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 780 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
742 i != rcvpq.end (); 781 i != rcvpq.end ();
743 ++i) 782 ++i)
744 delete *i; 783 delete *i;
745} 784}
746 785
786void
747void dns_connection::receive_rep (dns_rcv *r) 787dns_connection::receive_rep (dns_rcv *r)
748{ 788{
749 if (r->datalen) 789 if (r->datalen)
750 { 790 {
751 last_received = NOW; 791 last_received = ev_now ();
752 tw.trigger (); 792 tw ();
753 793
754 poll_interval = send_interval; 794 poll_interval = send_interval;
755 } 795 }
756 else 796 else
757 { 797 {
758 poll_interval *= 1.5; 798 poll_interval *= 1.5;
799
759 if (poll_interval > MAX_POLL_INTERVAL) 800 if (poll_interval > MAX_POLL_INTERVAL)
760 poll_interval = MAX_POLL_INTERVAL; 801 poll_interval = MAX_POLL_INTERVAL;
761 } 802 }
762 803
763 rcvpq.push_back (r); 804 rcvpq.push_back (r);
… …
766 807
767 // find next packet 808 // find next packet
768 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 809 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
769 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 810 if (SEQNO_EQ (rcvseq, (*i)->seqno))
770 { 811 {
812 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
771 // enter the packet into our input stream 813 // enter the packet into our input stream
772 r = *i; 814 r = *i;
773 815
774 // remove the oldest packet, look forward, as it's oldest first 816 // remove the oldest packet, look forward, as it's oldest first
775 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 817 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
776 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 818 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
777 { 819 {
820 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
778 delete *j; 821 delete *j;
779 rcvpq.erase (j); 822 rcvpq.erase (j);
780 break; 823 break;
781 } 824 }
782 825
783 rcvseq = (rcvseq + 1) & SEQNO_MASK; 826 rcvseq = (rcvseq + 1) & SEQNO_MASK;
784 827
785 if (!rcvdq.put (r->data, r->datalen)) 828 if (!rcvdq.put (r->data, r->datalen))
786 { 829 {
830 // MUST never overflow, can be caused by data corruption, TODO
787 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 831 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
788 abort (); // MUST never overflow, can be caused by data corruption, TODO 832 c->dnsv4_reset_connection ();
833 return;
789 } 834 }
790 835
791 while (vpn_packet *pkt = rcvdq.get ()) 836 while (vpn_packet *pkt = rcvdq.get ())
792 { 837 {
793 sockinfo si; 838 sockinfo si;
794 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 839 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
795 840
796 vpn->recv_vpn_packet (pkt, si); 841 vpn->recv_vpn_packet (pkt, si);
797
798 delete pkt; 842 delete pkt;
799 } 843 }
800 844
801 // check for further packets 845 // check for further packets
802 goto redo; 846 goto redo;
… …
853 if (0 < client && client <= conns.size ()) 897 if (0 < client && client <= conns.size ())
854 { 898 {
855 connection *c = conns [client - 1]; 899 connection *c = conns [client - 1];
856 dns_connection *dns = c->dns; 900 dns_connection *dns = c->dns;
857 dns_rcv *rcv; 901 dns_rcv *rcv;
858 bool in_seq;
859 902
860 if (dns) 903 if (dns)
861 { 904 {
862 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 905 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
863 if (SEQNO_EQ ((*i)->seqno, seqno)) 906 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
874 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 917 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
875 918
876 goto duplicate_request; 919 goto duplicate_request;
877 } 920 }
878 921
879 in_seq = dns->rcvseq == seqno;
880
881 // new packet, queue 922 // new packet, queue
882 rcv = new dns_rcv (seqno, data, datalen); 923 rcv = new dns_rcv (seqno, data, datalen);
883 dns->receive_rep (rcv); 924 dns->receive_rep (rcv);
884 } 925 }
885 926
… …
892 pkt [offs++] = 0; pkt [offs++] = 0; 933 pkt [offs++] = 0; pkt [offs++] = 0;
893 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 934 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
894 935
895 int rdlen_offs = offs += 2; 936 int rdlen_offs = offs += 2;
896 937
897 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
898 // bind doesn't compress well, so reduce further by one label length
899 dlen -= qlen;
900
901 if (dns) 938 if (dns)
902 { 939 {
940 int dlen = ntohs (dns->cfg.max_size) - offs;
941
942 // bind doesn't compress well, so reduce further by one label length
943 dlen -= qlen;
944
903 // only put data into in-order sequence packets, if 945 // only put data into in-order sequence packets, if
904 // we receive out-of-order packets we generate empty 946 // we receive out-of-order packets we generate empty
905 // replies 947 // replies
906 while (dlen > 1 && !dns->snddq.empty () && in_seq) 948 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
949 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
907 { 950 {
951 dns->repseq = seqno;
952
953 while (dlen > 1 && !dns->snddq.empty ())
954 {
908 int txtlen = dlen <= 255 ? dlen - 1 : 255; 955 int txtlen = dlen <= 255 ? dlen - 1 : 255;
909 956
910 if (txtlen > dns->snddq.size ()) 957 if (txtlen > dns->snddq.size ())
911 txtlen = dns->snddq.size (); 958 txtlen = dns->snddq.size ();
912 959
913 pkt[offs++] = txtlen; 960 pkt[offs++] = txtlen;
914 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 961 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
915 offs += txtlen; 962 offs += txtlen;
916 dns->snddq.remove (txtlen); 963 dns->snddq.remove (txtlen);
917 964
918 dlen -= txtlen + 1; 965 dlen -= txtlen + 1;
966 }
919 } 967 }
920 968
921 // avoid empty TXT rdata 969 // avoid completely empty TXT rdata
922 if (offs == rdlen_offs) 970 if (offs == rdlen_offs)
923 pkt[offs++] = 0; 971 pkt[offs++] = 0;
924 972
925 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 973 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
926 } 974 }
… …
1006 { 1054 {
1007 dns_connection *dns = (*i)->dns; 1055 dns_connection *dns = (*i)->dns;
1008 connection *c = dns->c; 1056 connection *c = dns->c;
1009 int seqno = (*i)->seqno; 1057 int seqno = (*i)->seqno;
1010 u8 data[MAXSIZE], *datap = data; 1058 u8 data[MAXSIZE], *datap = data;
1059 //printf ("rcv pkt %x\n", seqno);//D
1011 1060
1012 if ((*i)->retry) 1061 if ((*i)->retry)
1013 { 1062 {
1014 dns->send_interval *= 1.01; 1063 dns->send_interval *= 1.01;
1015 if (dns->send_interval > MAX_SEND_INTERVAL) 1064 if (dns->send_interval > MAX_SEND_INTERVAL)
1016 dns->send_interval = MAX_SEND_INTERVAL; 1065 dns->send_interval = MAX_SEND_INTERVAL;
1017 } 1066 }
1018 else 1067 else
1019 { 1068 {
1020#if 1 1069#if 0
1021 dns->send_interval *= 0.999; 1070 dns->send_interval *= 0.999;
1022#endif 1071#endif
1023 if (dns->send_interval < MIN_SEND_INTERVAL)
1024 dns->send_interval = MIN_SEND_INTERVAL;
1025
1026 // the latency surely puts an upper bound on 1072 // the latency surely puts an upper bound on
1027 // the minimum send interval 1073 // the minimum send interval
1028 double latency = NOW - (*i)->sent; 1074 double latency = ev_now () - (*i)->sent;
1075
1076 if (latency < dns->min_latency)
1029 dns->last_latency = latency; 1077 dns->min_latency = latency;
1030 1078
1031 if (dns->send_interval > latency) 1079 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1080 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1081
1082 if (dns->send_interval < conf.dns_send_interval)
1032 dns->send_interval = latency; 1083 dns->send_interval = conf.dns_send_interval;
1033 } 1084 }
1034 1085
1035 delete *i; 1086 delete *i;
1036 dns_sndpq.erase (i); 1087 dns_sndpq.erase (i);
1037 1088
… …
1093 1144
1094 if (ip [3] == CMD_IP_RST) 1145 if (ip [3] == CMD_IP_RST)
1095 { 1146 {
1096 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1147 slog (L_DEBUG, _("DNS: got tunnel RST request"));
1097 1148
1098 delete dns; c->dns = 0; 1149 c->dnsv4_reset_connection ();
1099
1100 return;
1101 } 1150 }
1102 else if (ip [3] == CMD_IP_SYN) 1151 else if (ip [3] == CMD_IP_SYN)
1103 { 1152 {
1104 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1153 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1105 dns->established = true; 1154 dns->established = true;
1106 } 1155 }
1107 else if (ip [3] == CMD_IP_REJ) 1156 else if (ip [3] == CMD_IP_REJ)
1108 {
1109 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1157 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1110 abort ();
1111 }
1112 else 1158 else
1113 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1159 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1114 } 1160 }
1115 else 1161 else
1116 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1162 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
… …
1142 break; 1188 break;
1143 } 1189 }
1144} 1190}
1145 1191
1146void 1192void
1147vpn::dnsv4_ev (io_watcher &w, short revents) 1193vpn::dnsv4_ev (ev::io &w, int revents)
1148{ 1194{
1149 if (revents & EVENT_READ) 1195 if (revents & EV_READ)
1150 { 1196 {
1151 dns_packet *pkt = new dns_packet; 1197 dns_packet *pkt = new dns_packet;
1152 struct sockaddr_in sa; 1198 struct sockaddr_in sa;
1153 socklen_t sa_len = sizeof (sa); 1199 socklen_t sa_len = sizeof (sa);
1154 1200
… …
1170} 1216}
1171 1217
1172bool 1218bool
1173vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1219vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1174{ 1220{
1175 int client = ntohs (si.port); 1221 int client = ntohl (si.host);
1176 1222
1177 assert (0 < client && client <= conns.size ()); 1223 assert (0 < client && client <= conns.size ());
1178 1224
1179 connection *c = conns [client - 1]; 1225 connection *c = conns [client - 1];
1180 1226
1181 if (!c->dns) 1227 if (!c->dns)
1182 c->dns = new dns_connection (c); 1228 c->dns = new dns_connection (c);
1183 1229
1184 if (!c->dns->snddq.put (pkt)) 1230 if (c->dns->snddq.put (pkt))
1185 return false;
1186
1187 c->dns->tw.trigger (); 1231 c->dns->tw ();
1188 1232
1233 // always return true even if the buffer overflows
1189 return true; 1234 return true;
1190} 1235}
1191 1236
1192void 1237void
1193connection::dnsv4_reset_connection () 1238connection::dnsv4_reset_connection ()
… …
1196} 1241}
1197 1242
1198#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1243#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1199 1244
1200void 1245void
1201dns_connection::time_cb (time_watcher &w) 1246dns_connection::time_cb (ev::timer &w, int revents)
1202{ 1247{
1203 // servers have to be polled 1248 // servers have to be polled
1204 if (THISNODE->dns_port) 1249 if (THISNODE->dns_port)
1205 return; 1250 return;
1206 1251
1207 // check for timeouts and (re)transmit 1252 // check for timeouts and (re)transmit
1208 tstamp next = NOW + poll_interval; 1253 tstamp next = ev::now () + poll_interval;
1209 dns_snd *send = 0; 1254 dns_snd *send = 0;
1210 1255
1211 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1256 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1212 i != vpn->dns_sndpq.end (); 1257 i != vpn->dns_sndpq.end ();
1213 ++i) 1258 ++i)
1214 { 1259 {
1215 dns_snd *r = *i; 1260 dns_snd *r = *i;
1216 1261
1217 if (r->timeout <= NOW) 1262 if (r->timeout <= ev_now ())
1218 { 1263 {
1219 if (!send) 1264 if (!send)
1220 { 1265 {
1221 send = r; 1266 send = r;
1222 1267
1223 r->retry++; 1268 r->retry++;
1224 r->timeout = NOW + (r->retry * last_latency * 8.); 1269 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1270 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1225 1271
1226 // the following code changes the query section a bit, forcing 1272 // the following code changes the query section a bit, forcing
1227 // the forwarder to generate a new request 1273 // the forwarder to generate a new request
1228 if (r->stdhdr) 1274 if (r->stdhdr)
1229 {
1230 //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);
1231 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1275 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1232 }
1233 } 1276 }
1234 } 1277 }
1235 else 1278 else
1236 NEXT (r->timeout); 1279 NEXT (r->timeout);
1237 } 1280 }
1238 1281
1239 if (last_sent + send_interval <= NOW)
1240 {
1241 if (!send) 1282 if (!send)
1283 {
1284 // generate a new packet, if wise
1285
1286 if (!established)
1242 { 1287 {
1243 // generate a new packet, if wise 1288 if (vpn->dns_sndpq.empty ())
1244
1245 if (!established)
1246 { 1289 {
1247 if (vpn->dns_sndpq.empty ())
1248 {
1249 send = new dns_snd (this); 1290 send = new dns_snd (this);
1250 1291
1251 cfg.reset (THISNODE->id); 1292 cfg.reset (THISNODE->id);
1252 send->gen_syn_req (); 1293 send->gen_syn_req ();
1253 }
1254 } 1294 }
1255 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1295 }
1296 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1256 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1297 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1298 {
1299 if (last_sent + send_interval <= ev_now ())
1257 { 1300 {
1258 //printf ("sending data request etc.\n"); //D 1301 //printf ("sending data request etc.\n"); //D
1259 if (!snddq.empty ()) 1302 if (!snddq.empty () || last_received + 1. > ev_now ())
1260 { 1303 {
1261 poll_interval = send_interval; 1304 poll_interval = send_interval;
1262 NEXT (NOW + send_interval); 1305 NEXT (ev_now () + send_interval);
1263 } 1306 }
1264 1307
1265 send = new dns_snd (this); 1308 send = new dns_snd (this);
1266 send->gen_stream_req (sndseq, snddq); 1309 send->gen_stream_req (sndseq, snddq);
1267 send->timeout = NOW + last_latency * 8.; 1310 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1311 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1268 1312
1269 sndseq = (sndseq + 1) & SEQNO_MASK; 1313 sndseq = (sndseq + 1) & SEQNO_MASK;
1270 } 1314 }
1271 1315 else
1272 if (send) 1316 NEXT (last_sent + send_interval);
1273 vpn->dns_sndpq.push_back (send);
1274 } 1317 }
1275 1318
1276 if (send) 1319 if (send)
1277 { 1320 vpn->dns_sndpq.push_back (send);
1278 last_sent = NOW; 1321 }
1322
1323 if (send)
1324 {
1325 last_sent = ev_now ();
1279 sendto (vpn->dnsv4_fd, 1326 sendto (vpn->dnsv4_fd,
1280 send->pkt->at (0), send->pkt->len, 0, 1327 send->pkt->at (0), send->pkt->len, 0,
1281 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1328 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1282 }
1283 } 1329 }
1284 else
1285 NEXT (last_sent + send_interval);
1286 1330
1287 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1331 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1288 poll_interval, send_interval, next - NOW, 1332 poll_interval, send_interval, next - ev_now (),
1289 vpn->dns_sndpq.size (), snddq.size ()); 1333 vpn->dns_sndpq.size (), snddq.size (),
1334 rcvpq.size ());
1290 1335
1291 // TODO: no idea when this happens, but when next < NOW, we have a problem 1336 // TODO: no idea when this happens, but when next < ev_now (), we have a problem
1337 // doesn't seem to happen anymore
1292 if (next < NOW + 0.0001) 1338 if (next < ev_now () + 0.001)
1293 next = NOW + 0.1; 1339 next = ev_now () + 0.1;
1294 1340
1295 w.start (next); 1341 w.start (next - ev_now ());
1296} 1342}
1297 1343
1298#endif 1344#endif
1299 1345

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