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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.25 by pcg, Mon Mar 7 22:24:24 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 LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
60#define MAX_OUTSTANDING 20 // max. outstanding requests
61#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
62#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
63 74
64#define MAX_DOMAIN_SIZE 200 // 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
65// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
66// every two request bytes less give room for one reply byte 77// every request byte less give room for two reply bytes
67 78
68#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
69#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
70 81
71#define MAX_LBL_SIZE 63 82#define MAX_LBL_SIZE 63
72#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
73 84
74#define RR_TYPE_A 1 85#define RR_TYPE_A 1
75#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
76#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
77#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
78 90
79#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
80 92
81#define CMD_IP_1 207 93#define CMD_IP_1 207
… …
105 memset (enc, (char) 0, 256); 117 memset (enc, (char) 0, 256);
106 memset (dec, (char)INVALID, 256); 118 memset (dec, (char)INVALID, 256);
107 119
108 for (size = 0; cmap [size]; size++) 120 for (size = 0; cmap [size]; size++)
109 { 121 {
122 char c = cmap [size];
123
110 enc [size] = cmap [size]; 124 enc [size] = c;
111 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;
112 } 130 }
113 131
114 assert (size < 256); 132 assert (size < 256);
115} 133}
116 134
… …
156 enc_len [len] = n; 174 enc_len [len] = n;
157 dec_len [n] = len; 175 dec_len [n] = len;
158 } 176 }
159} 177}
160 178
179unsigned int
161unsigned int basecoder::encode_len (unsigned int len) 180basecoder::encode_len (unsigned int len)
162{ 181{
163 return enc_len [len]; 182 return enc_len [len];
164} 183}
165 184
185unsigned int
166unsigned int basecoder::decode_len (unsigned int len) 186basecoder::decode_len (unsigned int len)
167{ 187{
168 while (len && !dec_len [len]) 188 while (len && !dec_len [len])
169 --len; 189 --len;
170 190
171 return dec_len [len]; 191 return dec_len [len];
172} 192}
173 193
194unsigned int
174unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 195basecoder::encode (char *dst, u8 *src, unsigned int len)
175{ 196{
176 if (!len || len > MAX_DEC_LEN) 197 if (!len || len > MAX_DEC_LEN)
177 return 0; 198 return 0;
178 199
179 int elen = encode_len (len); 200 int elen = encode_len (len);
… …
198 *dst++ = cmap.encode [dst_ [i]]; 219 *dst++ = cmap.encode [dst_ [i]];
199 220
200 return elen; 221 return elen;
201} 222}
202 223
224unsigned int
203unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 225basecoder::decode (u8 *dst, char *src, unsigned int len)
204{ 226{
205 if (!len || len > MAX_ENC_LEN) 227 if (!len || len > MAX_ENC_LEN)
206 return 0; 228 return 0;
207 229
208 u8 src_ [MAX_ENC_LEN]; 230 u8 src_ [MAX_ENC_LEN];
… …
267 289
268///////////////////////////////////////////////////////////////////////////// 290/////////////////////////////////////////////////////////////////////////////
269 291
270#define HDRSIZE 6 292#define HDRSIZE 6
271 293
294inline void
272inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 295encode_header (char *data, int clientid, int seqno, int retry = 0)
273{ 296{
274 seqno &= SEQNO_MASK; 297 seqno &= SEQNO_MASK;
275 298
276 u8 hdr[3] = { 299 u8 hdr[3] = {
277 clientid, 300 clientid,
… …
282 assert (clientid < 256); 305 assert (clientid < 256);
283 306
284 cdc26.encode (data, hdr, 3); 307 cdc26.encode (data, hdr, 3);
285} 308}
286 309
310inline void
287inline void decode_header (char *data, int &clientid, int &seqno) 311decode_header (char *data, int &clientid, int &seqno)
288{ 312{
289 u8 hdr[3]; 313 u8 hdr[3];
290 314
291 cdc26.decode (hdr, data, HDRSIZE); 315 cdc26.decode (hdr, data, HDRSIZE);
292 316
… …
325byte_stream::~byte_stream () 349byte_stream::~byte_stream ()
326{ 350{
327 delete data; 351 delete data;
328} 352}
329 353
354void
330void byte_stream::remove (int count) 355byte_stream::remove (int count)
331{ 356{
332 if (count > fill) 357 if (count > fill)
333 assert (count <= fill); 358 assert (count <= fill);
334 359
335 memmove (data, data + count, fill -= count); 360 memmove (data, data + count, fill -= count);
336} 361}
337 362
363bool
338bool byte_stream::put (u8 *data, unsigned int datalen) 364byte_stream::put (u8 *data, unsigned int datalen)
339{ 365{
340 if (maxsize - fill < datalen) 366 if (maxsize - fill < datalen)
341 return false; 367 return false;
342 368
343 memcpy (this->data + fill, data, datalen); fill += datalen; 369 memcpy (this->data + fill, data, datalen); fill += datalen;
344 370
345 return true; 371 return true;
346} 372}
347 373
374bool
348bool byte_stream::put (vpn_packet *pkt) 375byte_stream::put (vpn_packet *pkt)
349{ 376{
350 if (maxsize - fill < pkt->len + 2) 377 if (maxsize - fill < pkt->len + 2)
351 return false; 378 return false;
352 379
353 data [fill++] = pkt->len >> 8; 380 data [fill++] = pkt->len >> 8;
… …
424 u16 max_size; 451 u16 max_size;
425 u8 seq_cdc; 452 u8 seq_cdc;
426 u8 req_cdc; 453 u8 req_cdc;
427 454
428 u8 rep_cdc; 455 u8 rep_cdc;
456 u8 delay; // time in 0.01s units that the server may delay replying packets
429 u8 r2, r3, r4; 457 u8 r3, r4;
430 458
431 u8 r5, r6, r7, r8; 459 u8 r5, r6, r7, r8;
432 460
433 void reset (int clientid); 461 void reset (int clientid);
434 bool valid (); 462 bool valid ();
435}; 463};
436 464
437int dns_cfg::next_uid; 465int dns_cfg::next_uid;
438 466
467void
439void dns_cfg::reset (int clientid) 468dns_cfg::reset (int clientid)
440{ 469{
441 id1 = 'G'; 470 id1 = 'G';
442 id2 = 'V'; 471 id2 = 'V';
443 id3 = 'P'; 472 id3 = 'P';
444 id4 = 'E'; 473 id4 = 'E';
… …
449 flags = 0; 478 flags = 0;
450 def_ttl = 0; 479 def_ttl = 0;
451 seq_cdc = 26; 480 seq_cdc = 26;
452 req_cdc = 62; 481 req_cdc = 62;
453 rep_cdc = 0; 482 rep_cdc = 0;
454 max_size = ntohs (MAX_PKT_SIZE); 483 max_size = htons (MAX_PKT_SIZE);
455 client = ntohs (clientid); 484 client = htons (clientid);
456 uid = next_uid++; 485 uid = next_uid++;
486 delay = 0;
457 487
458 r2 = r3 = r4 = 0; 488 r3 = r4 = 0;
459 r4 = r5 = r6 = r7 = 0; 489 r4 = r5 = r6 = r7 = 0;
460} 490}
461 491
492bool
462bool dns_cfg::valid () 493dns_cfg::valid ()
463{ 494{
495 // although the protocol itself allows for some configurability,
496 // only the following encoding/decoding settings are implemented.
464 return id1 == 'G' 497 return id1 == 'G'
465 && id2 == 'V' 498 && id2 == 'V'
466 && id3 == 'P' 499 && id3 == 'P'
467 && id4 == 'E' 500 && id4 == 'E'
468 && seq_cdc == 26 501 && seq_cdc == 26
469 && req_cdc == 62 502 && req_cdc == 62
470 && rep_cdc == 0 503 && rep_cdc == 0
471 && version == 1 504 && version == 1;
472 && max_size == ntohs (MAX_PKT_SIZE);
473} 505}
474 506
475struct dns_packet : net_packet 507struct dns_packet : net_packet
476{ 508{
477 u16 id; 509 u16 id;
… …
481 u8 data [MAXSIZE - 6 * 2]; 513 u8 data [MAXSIZE - 6 * 2];
482 514
483 int decode_label (char *data, int size, int &offs); 515 int decode_label (char *data, int size, int &offs);
484}; 516};
485 517
518int
486int dns_packet::decode_label (char *data, int size, int &offs) 519dns_packet::decode_label (char *data, int size, int &offs)
487{ 520{
488 char *orig = data; 521 char *orig = data;
489 522
490 memset (data, 0, size); 523 memset (data, 0, size);
491 524
… …
517 return data - orig; 550 return data - orig;
518} 551}
519 552
520///////////////////////////////////////////////////////////////////////////// 553/////////////////////////////////////////////////////////////////////////////
521 554
555static
556u16 next_id ()
557{
522static u16 dns_id = 0; // TODO: should be per-vpn 558 static u16 dns_id = 0; // TODO: should be per-vpn
523 559
524static u16 next_id ()
525{
526 if (!dns_id) 560 if (!dns_id)
527 dns_id = time (0); 561 dns_id = time (0);
528 562
529 // the simplest lsfr with periodicity 65535 i could find 563 // the simplest lsfr with periodicity 65535 i could find
530 dns_id = (dns_id << 1) 564 dns_id = (dns_id << 1)
… …
553 double min_latency; 587 double min_latency;
554 double poll_interval, send_interval; 588 double poll_interval, send_interval;
555 589
556 vector<dns_rcv *> rcvpq; 590 vector<dns_rcv *> rcvpq;
557 591
558 byte_stream rcvdq; int rcvseq; 592 byte_stream rcvdq; int rcvseq; int repseq;
559 byte_stream snddq; int sndseq; 593 byte_stream snddq; int sndseq;
560 594
561 void time_cb (time_watcher &w); time_watcher tw; 595 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
562 void receive_rep (dns_rcv *r); 596 void receive_rep (dns_rcv *r);
563 597
564 dns_connection (connection *c); 598 dns_connection (connection *c);
565 ~dns_connection (); 599 ~dns_connection ();
566}; 600};
… …
585: dns (dns) 619: dns (dns)
586{ 620{
587 timeout = 0; 621 timeout = 0;
588 retry = 0; 622 retry = 0;
589 seqno = 0; 623 seqno = 0;
590 sent = NOW; 624 sent = ev_now ();
591 stdhdr = false; 625 stdhdr = false;
592 626
593 pkt = new dns_packet; 627 pkt = new dns_packet;
594 628
595 pkt->id = next_id (); 629 pkt->id = next_id ();
… …
598dns_snd::~dns_snd () 632dns_snd::~dns_snd ()
599{ 633{
600 delete pkt; 634 delete pkt;
601} 635}
602 636
637static void
603static void append_domain (dns_packet &pkt, int &offs, const char *domain) 638append_domain (dns_packet &pkt, int &offs, const char *domain)
604{ 639{
605 // add tunnel domain 640 // add tunnel domain
606 for (;;) 641 for (;;)
607 { 642 {
608 const char *end = strchr (domain, '.'); 643 const char *end = strchr (domain, '.');
… …
621 656
622 domain = end + 1; 657 domain = end + 1;
623 } 658 }
624} 659}
625 660
661void
626void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 662dns_snd::gen_stream_req (int seqno, byte_stream &stream)
627{ 663{
628 stdhdr = true; 664 stdhdr = true;
629 this->seqno = seqno; 665 this->seqno = seqno;
630 666
631 timeout = NOW + INITIAL_TIMEOUT; 667 timeout = ev_now () + INITIAL_TIMEOUT;
632 668
633 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 669 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
634 pkt->qdcount = htons (1); 670 pkt->qdcount = htons (1);
635 671
636 int offs = 6*2; 672 int offs = 6*2;
… …
669 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 705 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
670 706
671 pkt->len = offs; 707 pkt->len = offs;
672} 708}
673 709
710void
674void dns_snd::gen_syn_req () 711dns_snd::gen_syn_req ()
675{ 712{
676 timeout = NOW + INITIAL_SYN_TIMEOUT; 713 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
677 714
678 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 715 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
679 pkt->qdcount = htons (1); 716 pkt->qdcount = htons (1);
680 717
681 int offs = 6 * 2; 718 int offs = 6 * 2;
… …
720///////////////////////////////////////////////////////////////////////////// 757/////////////////////////////////////////////////////////////////////////////
721 758
722dns_connection::dns_connection (connection *c) 759dns_connection::dns_connection (connection *c)
723: c (c) 760: c (c)
724, rcvdq (MAX_BACKLOG * 2) 761, rcvdq (MAX_BACKLOG * 2)
725, snddq (MAX_BACKLOG * 2) 762, snddq (MAX_BACKLOG)
726, tw (this, &dns_connection::time_cb)
727{ 763{
764 tw.set<dns_connection, &dns_connection::time_cb> (this);
765
728 vpn = c->vpn; 766 vpn = c->vpn;
729 767
730 established = false; 768 established = false;
731 769
732 rcvseq = sndseq = 0; 770 rcvseq = repseq = sndseq = 0;
733 771
734 last_sent = last_received = 0; 772 last_sent = last_received = 0;
735 poll_interval = MIN_POLL_INTERVAL; 773 poll_interval = 0.5; // starting here
736 send_interval = 0.5; // starting rate 774 send_interval = 0.5; // starting rate
737 min_latency = INITIAL_TIMEOUT; 775 min_latency = INITIAL_TIMEOUT;
738} 776}
739 777
740dns_connection::~dns_connection () 778dns_connection::~dns_connection ()
… …
743 i != rcvpq.end (); 781 i != rcvpq.end ();
744 ++i) 782 ++i)
745 delete *i; 783 delete *i;
746} 784}
747 785
786void
748void dns_connection::receive_rep (dns_rcv *r) 787dns_connection::receive_rep (dns_rcv *r)
749{ 788{
750 if (r->datalen) 789 if (r->datalen)
751 { 790 {
752 last_received = NOW; 791 last_received = ev_now ();
753 tw.trigger (); 792 tw ();
754 793
755 poll_interval = send_interval; 794 poll_interval = send_interval;
756 } 795 }
757 else 796 else
758 { 797 {
… …
768 807
769 // find next packet 808 // find next packet
770 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 809 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
771 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 810 if (SEQNO_EQ (rcvseq, (*i)->seqno))
772 { 811 {
812 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
773 // enter the packet into our input stream 813 // enter the packet into our input stream
774 r = *i; 814 r = *i;
775 815
776 // remove the oldest packet, look forward, as it's oldest first 816 // remove the oldest packet, look forward, as it's oldest first
777 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)
778 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 818 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
779 { 819 {
820 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
780 delete *j; 821 delete *j;
781 rcvpq.erase (j); 822 rcvpq.erase (j);
782 break; 823 break;
783 } 824 }
784 825
785 rcvseq = (rcvseq + 1) & SEQNO_MASK; 826 rcvseq = (rcvseq + 1) & SEQNO_MASK;
786 827
787 if (!rcvdq.put (r->data, r->datalen)) 828 if (!rcvdq.put (r->data, r->datalen))
788 { 829 {
830 // MUST never overflow, can be caused by data corruption, TODO
789 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 831 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
790 abort (); // MUST never overflow, can be caused by data corruption, TODO 832 c->dnsv4_reset_connection ();
833 return;
791 } 834 }
792 835
793 while (vpn_packet *pkt = rcvdq.get ()) 836 while (vpn_packet *pkt = rcvdq.get ())
794 { 837 {
795 sockinfo si; 838 sockinfo si;
796 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;
797 840
798 vpn->recv_vpn_packet (pkt, si); 841 vpn->recv_vpn_packet (pkt, si);
799
800 delete pkt; 842 delete pkt;
801 } 843 }
802 844
803 // check for further packets 845 // check for further packets
804 goto redo; 846 goto redo;
… …
855 if (0 < client && client <= conns.size ()) 897 if (0 < client && client <= conns.size ())
856 { 898 {
857 connection *c = conns [client - 1]; 899 connection *c = conns [client - 1];
858 dns_connection *dns = c->dns; 900 dns_connection *dns = c->dns;
859 dns_rcv *rcv; 901 dns_rcv *rcv;
860 bool in_seq;
861 902
862 if (dns) 903 if (dns)
863 { 904 {
864 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 (); )
865 if (SEQNO_EQ ((*i)->seqno, seqno)) 906 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
876 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);
877 918
878 goto duplicate_request; 919 goto duplicate_request;
879 } 920 }
880 921
881 in_seq = dns->rcvseq == seqno;
882
883 // new packet, queue 922 // new packet, queue
884 rcv = new dns_rcv (seqno, data, datalen); 923 rcv = new dns_rcv (seqno, data, datalen);
885 dns->receive_rep (rcv); 924 dns->receive_rep (rcv);
886 } 925 }
887 926
… …
894 pkt [offs++] = 0; pkt [offs++] = 0; 933 pkt [offs++] = 0; pkt [offs++] = 0;
895 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
896 935
897 int rdlen_offs = offs += 2; 936 int rdlen_offs = offs += 2;
898 937
899 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
900 // bind doesn't compress well, so reduce further by one label length
901 dlen -= qlen;
902
903 if (dns) 938 if (dns)
904 { 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
905 // only put data into in-order sequence packets, if 945 // only put data into in-order sequence packets, if
906 // we receive out-of-order packets we generate empty 946 // we receive out-of-order packets we generate empty
907 // replies 947 // replies
908 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)
909 { 950 {
951 dns->repseq = seqno;
952
953 while (dlen > 1 && !dns->snddq.empty ())
954 {
910 int txtlen = dlen <= 255 ? dlen - 1 : 255; 955 int txtlen = dlen <= 255 ? dlen - 1 : 255;
911 956
912 if (txtlen > dns->snddq.size ()) 957 if (txtlen > dns->snddq.size ())
913 txtlen = dns->snddq.size (); 958 txtlen = dns->snddq.size ();
914 959
915 pkt[offs++] = txtlen; 960 pkt[offs++] = txtlen;
916 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 961 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
917 offs += txtlen; 962 offs += txtlen;
918 dns->snddq.remove (txtlen); 963 dns->snddq.remove (txtlen);
919 964
920 dlen -= txtlen + 1; 965 dlen -= txtlen + 1;
966 }
921 } 967 }
922 968
923 // avoid empty TXT rdata 969 // avoid completely empty TXT rdata
924 if (offs == rdlen_offs) 970 if (offs == rdlen_offs)
925 pkt[offs++] = 0; 971 pkt[offs++] = 0;
926 972
927 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 973 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
928 } 974 }
… …
1008 { 1054 {
1009 dns_connection *dns = (*i)->dns; 1055 dns_connection *dns = (*i)->dns;
1010 connection *c = dns->c; 1056 connection *c = dns->c;
1011 int seqno = (*i)->seqno; 1057 int seqno = (*i)->seqno;
1012 u8 data[MAXSIZE], *datap = data; 1058 u8 data[MAXSIZE], *datap = data;
1059 //printf ("rcv pkt %x\n", seqno);//D
1013 1060
1014 if ((*i)->retry) 1061 if ((*i)->retry)
1015 { 1062 {
1016 dns->send_interval *= 1.01; 1063 dns->send_interval *= 1.01;
1017 if (dns->send_interval > MAX_SEND_INTERVAL) 1064 if (dns->send_interval > MAX_SEND_INTERVAL)
1018 dns->send_interval = MAX_SEND_INTERVAL; 1065 dns->send_interval = MAX_SEND_INTERVAL;
1019 } 1066 }
1020 else 1067 else
1021 { 1068 {
1022#if 1 1069#if 0
1023 dns->send_interval *= 0.999; 1070 dns->send_interval *= 0.999;
1024#endif 1071#endif
1025 if (dns->send_interval < MIN_SEND_INTERVAL)
1026 dns->send_interval = MIN_SEND_INTERVAL;
1027
1028 // the latency surely puts an upper bound on 1072 // the latency surely puts an upper bound on
1029 // the minimum send interval 1073 // the minimum send interval
1030 double latency = NOW - (*i)->sent; 1074 double latency = ev_now () - (*i)->sent;
1031 1075
1032 if (latency < dns->min_latency) 1076 if (latency < dns->min_latency)
1033 dns->min_latency = latency; 1077 dns->min_latency = latency;
1034 1078
1035 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR) 1079 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1036 dns->send_interval = dns->min_latency * LATENCY_FACTOR; 1080 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1081
1082 if (dns->send_interval < conf.dns_send_interval)
1083 dns->send_interval = conf.dns_send_interval;
1037 } 1084 }
1038 1085
1039 delete *i; 1086 delete *i;
1040 dns_sndpq.erase (i); 1087 dns_sndpq.erase (i);
1041 1088
… …
1097 1144
1098 if (ip [3] == CMD_IP_RST) 1145 if (ip [3] == CMD_IP_RST)
1099 { 1146 {
1100 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1147 slog (L_DEBUG, _("DNS: got tunnel RST request"));
1101 1148
1102 delete dns; c->dns = 0; 1149 c->dnsv4_reset_connection ();
1103
1104 return;
1105 } 1150 }
1106 else if (ip [3] == CMD_IP_SYN) 1151 else if (ip [3] == CMD_IP_SYN)
1107 { 1152 {
1108 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1153 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1109 dns->established = true; 1154 dns->established = true;
1110 } 1155 }
1111 else if (ip [3] == CMD_IP_REJ) 1156 else if (ip [3] == CMD_IP_REJ)
1112 {
1113 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."));
1114 abort ();
1115 }
1116 else 1158 else
1117 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1159 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1118 } 1160 }
1119 else 1161 else
1120 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"),
… …
1146 break; 1188 break;
1147 } 1189 }
1148} 1190}
1149 1191
1150void 1192void
1151vpn::dnsv4_ev (io_watcher &w, short revents) 1193vpn::dnsv4_ev (ev::io &w, int revents)
1152{ 1194{
1153 if (revents & EVENT_READ) 1195 if (revents & EV_READ)
1154 { 1196 {
1155 dns_packet *pkt = new dns_packet; 1197 dns_packet *pkt = new dns_packet;
1156 struct sockaddr_in sa; 1198 struct sockaddr_in sa;
1157 socklen_t sa_len = sizeof (sa); 1199 socklen_t sa_len = sizeof (sa);
1158 1200
… …
1174} 1216}
1175 1217
1176bool 1218bool
1177vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1219vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1178{ 1220{
1179 int client = ntohs (si.port); 1221 int client = ntohl (si.host);
1180 1222
1181 assert (0 < client && client <= conns.size ()); 1223 assert (0 < client && client <= conns.size ());
1182 1224
1183 connection *c = conns [client - 1]; 1225 connection *c = conns [client - 1];
1184 1226
1185 if (!c->dns) 1227 if (!c->dns)
1186 c->dns = new dns_connection (c); 1228 c->dns = new dns_connection (c);
1187 1229
1188 if (!c->dns->snddq.put (pkt)) 1230 if (c->dns->snddq.put (pkt))
1189 return false;
1190
1191 c->dns->tw.trigger (); 1231 c->dns->tw ();
1192 1232
1233 // always return true even if the buffer overflows
1193 return true; 1234 return true;
1194} 1235}
1195 1236
1196void 1237void
1197connection::dnsv4_reset_connection () 1238connection::dnsv4_reset_connection ()
… …
1200} 1241}
1201 1242
1202#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1243#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1203 1244
1204void 1245void
1205dns_connection::time_cb (time_watcher &w) 1246dns_connection::time_cb (ev::timer &w, int revents)
1206{ 1247{
1207 // servers have to be polled 1248 // servers have to be polled
1208 if (THISNODE->dns_port) 1249 if (THISNODE->dns_port)
1209 return; 1250 return;
1210 1251
1211 // check for timeouts and (re)transmit 1252 // check for timeouts and (re)transmit
1212 tstamp next = NOW + poll_interval; 1253 tstamp next = ev::now () + poll_interval;
1213 dns_snd *send = 0; 1254 dns_snd *send = 0;
1214 1255
1215 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1256 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1216 i != vpn->dns_sndpq.end (); 1257 i != vpn->dns_sndpq.end ();
1217 ++i) 1258 ++i)
1218 { 1259 {
1219 dns_snd *r = *i; 1260 dns_snd *r = *i;
1220 1261
1221 if (r->timeout <= NOW) 1262 if (r->timeout <= ev_now ())
1222 { 1263 {
1223 if (!send) 1264 if (!send)
1224 { 1265 {
1225 send = r; 1266 send = r;
1226 1267
1227 r->retry++; 1268 r->retry++;
1228 r->timeout = NOW + (r->retry * min_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
1229 1271
1230 // the following code changes the query section a bit, forcing 1272 // the following code changes the query section a bit, forcing
1231 // the forwarder to generate a new request 1273 // the forwarder to generate a new request
1232 if (r->stdhdr) 1274 if (r->stdhdr)
1233 {
1234 //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);
1235 //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);
1236 }
1237 } 1276 }
1238 } 1277 }
1239 else 1278 else
1240 NEXT (r->timeout); 1279 NEXT (r->timeout);
1241 } 1280 }
1242 1281
1243 if (last_sent + send_interval <= NOW)
1244 {
1245 if (!send) 1282 if (!send)
1283 {
1284 // generate a new packet, if wise
1285
1286 if (!established)
1246 { 1287 {
1247 // generate a new packet, if wise 1288 if (vpn->dns_sndpq.empty ())
1248
1249 if (!established)
1250 { 1289 {
1251 if (vpn->dns_sndpq.empty ())
1252 {
1253 send = new dns_snd (this); 1290 send = new dns_snd (this);
1254 1291
1255 cfg.reset (THISNODE->id); 1292 cfg.reset (THISNODE->id);
1256 send->gen_syn_req (); 1293 send->gen_syn_req ();
1257 }
1258 } 1294 }
1259 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1295 }
1296 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1260 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1297 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1298 {
1299 if (last_sent + send_interval <= ev_now ())
1261 { 1300 {
1262 //printf ("sending data request etc.\n"); //D 1301 //printf ("sending data request etc.\n"); //D
1263 if (!snddq.empty () || last_received + 1. > NOW) 1302 if (!snddq.empty () || last_received + 1. > ev_now ())
1264 { 1303 {
1265 poll_interval = send_interval; 1304 poll_interval = send_interval;
1266 NEXT (NOW + send_interval); 1305 NEXT (ev_now () + send_interval);
1267 } 1306 }
1268 1307
1269 send = new dns_snd (this); 1308 send = new dns_snd (this);
1270 send->gen_stream_req (sndseq, snddq); 1309 send->gen_stream_req (sndseq, snddq);
1271 send->timeout = NOW + min_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
1272 1312
1273 sndseq = (sndseq + 1) & SEQNO_MASK; 1313 sndseq = (sndseq + 1) & SEQNO_MASK;
1274 } 1314 }
1275 1315 else
1276 if (send) 1316 NEXT (last_sent + send_interval);
1277 vpn->dns_sndpq.push_back (send);
1278 } 1317 }
1279 1318
1280 if (send) 1319 if (send)
1281 { 1320 vpn->dns_sndpq.push_back (send);
1282 last_sent = NOW; 1321 }
1322
1323 if (send)
1324 {
1325 last_sent = ev_now ();
1283 sendto (vpn->dnsv4_fd, 1326 sendto (vpn->dnsv4_fd,
1284 send->pkt->at (0), send->pkt->len, 0, 1327 send->pkt->at (0), send->pkt->len, 0,
1285 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1328 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1286 }
1287 } 1329 }
1288 else
1289 NEXT (last_sent + send_interval);
1290 1330
1291 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)",
1292 poll_interval, send_interval, next - NOW, 1332 poll_interval, send_interval, next - ev_now (),
1293 vpn->dns_sndpq.size (), snddq.size ()); 1333 vpn->dns_sndpq.size (), snddq.size (),
1334 rcvpq.size ());
1294 1335
1295 // 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
1296 if (next < NOW + 0.0001) 1338 if (next < ev_now () + 0.001)
1297 next = NOW + 0.1; 1339 next = ev_now () + 0.1;
1298 1340
1299 w.start (next); 1341 w.start (next - ev_now ());
1300} 1342}
1301 1343
1302#endif 1344#endif
1303 1345

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