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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC vs.
Revision 1.24 by pcg, Mon Mar 7 01:31:26 2005 UTC

… …
25 25
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 26// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27// it's a hack, use only in emergency situations please. 27// it's a hack, use only in emergency situations please.
28 28
29#include <cstring> 29#include <cstring>
30#include <cassert>
30 31
31#include <sys/types.h> 32#include <sys/types.h>
32#include <sys/socket.h> 33#include <sys/socket.h>
33#include <sys/wait.h> 34#include <sys/wait.h>
34#include <sys/uio.h> 35#include <sys/uio.h>
… …
43 44
44#include "netcompat.h" 45#include "netcompat.h"
45 46
46#include "vpn.h" 47#include "vpn.h"
47 48
48#define MIN_POLL_INTERVAL .2 // how often to poll minimally when the server is having data 49#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 50#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data
50#define ACTIVITY_INTERVAL 5. 51#define ACTIVITY_INTERVAL 5.
51 52
52#define INITIAL_TIMEOUT 1. 53#define INITIAL_TIMEOUT 0.1 // retry timeouts
53#define INITIAL_SYN_TIMEOUT 2. 54#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn
54 55
55#define MIN_SEND_INTERVAL (1./1000.) 56#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
56#define MAX_SEND_INTERVAL 0.5 // optimistic? 57#define MAX_SEND_INTERVAL 0.5 // optimistic?
57 58
58#define MAX_OUTSTANDING 400 // max. outstanding requests 59#define MAX_OUTSTANDING 10 // max. outstanding requests
59#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING 60#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
60#define MAX_RATE 100 // requests/s
61#define MAX_BACKLOG (100*1024) // size of protocol backlog, must be > MAXSIZE 61#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
62 62
63#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well 63#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well
64// 240 leaves about 4 bytes of server reply data 64// 240 leaves about 4 bytes of server reply data
65// every two request byte sless give room for one reply byte 65// every two request bytes less give room for one reply byte
66 66
67#define SEQNO_MASK 0xffff 67#define SEQNO_MASK 0x3fff
68#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 68#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
69 69
70#define MAX_LBL_SIZE 63 70#define MAX_LBL_SIZE 63
71#define MAX_PKT_SIZE 512 71#define MAX_PKT_SIZE 512
72 72
… …
265static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 265static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
266 266
267///////////////////////////////////////////////////////////////////////////// 267/////////////////////////////////////////////////////////////////////////////
268 268
269#define HDRSIZE 6 269#define HDRSIZE 6
270 270
271inline void encode_header (char *data, int clientid, int seqno) 271inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
272{ 272{
273 u8 hdr[3] = { clientid, seqno >> 8, seqno }; 273 seqno &= SEQNO_MASK;
274
275 u8 hdr[3] = {
276 clientid,
277 (seqno >> 8) | (retry << 6),
278 seqno,
279 };
274 280
275 assert (clientid < 256); 281 assert (clientid < 256);
276 282
277 cdc26.encode (data, hdr, 3); 283 cdc26.encode (data, hdr, 3);
278} 284}
… …
282 u8 hdr[3]; 288 u8 hdr[3];
283 289
284 cdc26.decode (hdr, data, HDRSIZE); 290 cdc26.decode (hdr, data, HDRSIZE);
285 291
286 clientid = hdr[0]; 292 clientid = hdr[0];
287 seqno = (hdr[1] << 8) | hdr[2]; 293 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK;
288} 294}
289 295
290///////////////////////////////////////////////////////////////////////////// 296/////////////////////////////////////////////////////////////////////////////
291 297
292struct byte_stream 298struct byte_stream
… …
321} 327}
322 328
323void byte_stream::remove (int count) 329void byte_stream::remove (int count)
324{ 330{
325 if (count > fill) 331 if (count > fill)
326 abort (); 332 assert (count <= fill);
327 333
328 memmove (data, data + count, fill -= count); 334 memmove (data, data + count, fill -= count);
329} 335}
330 336
331bool byte_stream::put (u8 *data, unsigned int datalen) 337bool byte_stream::put (u8 *data, unsigned int datalen)
… …
351 return true; 357 return true;
352} 358}
353 359
354vpn_packet *byte_stream::get () 360vpn_packet *byte_stream::get ()
355{ 361{
362 unsigned int len;
363
364 for (;;)
365 {
356 int len = (data [0] << 8) | data [1]; 366 len = (data [0] << 8) | data [1];
357 367
358 if (len > MAXSIZE && fill >= 2) 368 if (len <= MAXSIZE || fill < 2)
359 abort (); // TODO handle this gracefully, connection reset 369 break;
360 370
371 // TODO: handle this better than skipping, e.g. by reset
372 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
373 remove (1);
374 }
375
361 if (fill < len + 2) 376 if (fill < len + 2)
362 return 0; 377 return 0;
363 378
364 vpn_packet *pkt = new vpn_packet; 379 vpn_packet *pkt = new vpn_packet;
365 380
… …
394struct dns_cfg 409struct dns_cfg
395{ 410{
396 static int next_uid; 411 static int next_uid;
397 412
398 u8 id1, id2, id3, id4; 413 u8 id1, id2, id3, id4;
414
399 u8 version; 415 u8 version;
416 u8 flags;
400 u8 rrtype; 417 u8 rrtype;
401 u8 flags;
402 u8 def_ttl; 418 u8 def_ttl;
403 u8 rcv_cdc; 419
404 u8 snd_cdc;
405 u16 max_size;
406 u16 client; 420 u16 client;
407 u16 uid; // to make request unique 421 u16 uid; // to make request unique
408 422
409 u8 reserved[8]; 423 u16 max_size;
424 u8 seq_cdc;
425 u8 req_cdc;
426
427 u8 rep_cdc;
428 u8 r2, r3, r4;
429
430 u8 r5, r6, r7, r8;
410 431
411 void reset (int clientid); 432 void reset (int clientid);
412 bool valid (); 433 bool valid ();
413}; 434};
414 435
… …
424 version = 1; 445 version = 1;
425 446
426 rrtype = RR_TYPE_TXT; 447 rrtype = RR_TYPE_TXT;
427 flags = 0; 448 flags = 0;
428 def_ttl = 0; 449 def_ttl = 0;
450 seq_cdc = 26;
451 req_cdc = 62;
429 rcv_cdc = 0; 452 rep_cdc = 0;
430 snd_cdc = 62;
431 max_size = ntohs (MAX_PKT_SIZE); 453 max_size = ntohs (MAX_PKT_SIZE);
432 client = ntohs (clientid); 454 client = ntohs (clientid);
433 uid = next_uid++; 455 uid = next_uid++;
434 456
435 memset (reserved, 0, 8); 457 r2 = r3 = r4 = 0;
458 r4 = r5 = r6 = r7 = 0;
436} 459}
437 460
438bool dns_cfg::valid () 461bool dns_cfg::valid ()
439{ 462{
440 return id1 == 'G' 463 return id1 == 'G'
441 && id2 == 'V' 464 && id2 == 'V'
442 && id3 == 'P' 465 && id3 == 'P'
443 && id4 == 'E' 466 && id4 == 'E'
467 && seq_cdc == 26
468 && req_cdc == 62
469 && rep_cdc == 0
444 && version == 1 470 && version == 1
445 && flags == 0
446 && rcv_cdc == 0
447 && snd_cdc == 62
448 && max_size == ntohs (MAX_PKT_SIZE); 471 && max_size == ntohs (MAX_PKT_SIZE);
449} 472}
450 473
451struct dns_packet : net_packet 474struct dns_packet : net_packet
452{ 475{
453 u16 id; 476 u16 id;
454 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 477 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
455 u16 qdcount, ancount, nscount, arcount; 478 u16 qdcount, ancount, nscount, arcount;
456 479
457 u8 data[MAXSIZE - 6 * 2]; 480 u8 data [MAXSIZE - 6 * 2];
458 481
459 int decode_label (char *data, int size, int &offs); 482 int decode_label (char *data, int size, int &offs);
460}; 483};
461 484
462int dns_packet::decode_label (char *data, int size, int &offs) 485int dns_packet::decode_label (char *data, int size, int &offs)
… …
493 return data - orig; 516 return data - orig;
494} 517}
495 518
496///////////////////////////////////////////////////////////////////////////// 519/////////////////////////////////////////////////////////////////////////////
497 520
498struct dns_snd
499{
500 dns_packet *pkt;
501 tstamp timeout, sent;
502 int retry;
503 struct dns_connection *dns;
504 int seqno;
505
506 dns_snd (dns_connection *dns);
507 void gen_stream_req (int seqno, byte_stream &stream);
508 void gen_syn_req (const dns_cfg &cfg);
509};
510
511static u16 dns_id = 12098; // TODO: should be per-vpn 521static u16 dns_id = 0; // TODO: should be per-vpn
512 522
513static u16 next_id () 523static u16 next_id ()
514{ 524{
525 if (!dns_id)
526 dns_id = time (0);
527
515 // the simplest lsfr with periodicity 65535 i could find 528 // the simplest lsfr with periodicity 65535 i could find
516 dns_id = (dns_id << 1) 529 dns_id = (dns_id << 1)
517 | (((dns_id >> 1) 530 | (((dns_id >> 1)
518 ^ (dns_id >> 2) 531 ^ (dns_id >> 2)
519 ^ (dns_id >> 4) 532 ^ (dns_id >> 4)
520 ^ (dns_id >> 15)) & 1); 533 ^ (dns_id >> 15)) & 1);
521 534
522 return dns_id; 535 return dns_id;
523} 536}
524 537
538struct dns_rcv;
539struct dns_snd;
540
541struct dns_connection
542{
543 connection *c;
544 struct vpn *vpn;
545
546 dns_cfg cfg;
547
548 bool established;
549
550 tstamp last_received;
551 tstamp last_sent;
552 double last_latency;
553 double poll_interval, send_interval;
554
555 vector<dns_rcv *> rcvpq;
556
557 byte_stream rcvdq; int rcvseq;
558 byte_stream snddq; int sndseq;
559
560 void time_cb (time_watcher &w); time_watcher tw;
561 void receive_rep (dns_rcv *r);
562
563 dns_connection (connection *c);
564 ~dns_connection ();
565};
566
567struct dns_snd
568{
569 dns_packet *pkt;
570 tstamp timeout, sent;
571 int retry;
572 struct dns_connection *dns;
573 int seqno;
574 bool stdhdr;
575
576 void gen_stream_req (int seqno, byte_stream &stream);
577 void gen_syn_req ();
578
579 dns_snd (dns_connection *dns);
580 ~dns_snd ();
581};
582
525dns_snd::dns_snd (dns_connection *dns) 583dns_snd::dns_snd (dns_connection *dns)
526: dns (dns) 584: dns (dns)
527{ 585{
528 timeout = 0; 586 timeout = 0;
529 retry = 0; 587 retry = 0;
530 seqno = 0; 588 seqno = 0;
589 sent = NOW;
590 stdhdr = false;
531 591
532 pkt = new dns_packet; 592 pkt = new dns_packet;
533 593
534 pkt->id = next_id (); 594 pkt->id = next_id ();
595}
596
597dns_snd::~dns_snd ()
598{
599 delete pkt;
535} 600}
536 601
537static void append_domain (dns_packet &pkt, int &offs, const char *domain) 602static void append_domain (dns_packet &pkt, int &offs, const char *domain)
538{ 603{
539 // add tunnel domain 604 // add tunnel domain
… …
557 } 622 }
558} 623}
559 624
560void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 625void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
561{ 626{
627 stdhdr = true;
562 this->seqno = seqno; 628 this->seqno = seqno;
563 629
564 timeout = NOW + INITIAL_TIMEOUT; 630 timeout = NOW + INITIAL_TIMEOUT;
565 631
566 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 632 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
567 pkt->qdcount = htons (1); 633 pkt->qdcount = htons (1);
568 634
569 int offs = 6*2; 635 int offs = 6*2;
570 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 636 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
571 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 637 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
572 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 638 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
573 639
574 char enc[256], *encp = enc; 640 char enc[256], *encp = enc;
575 encode_header (enc, THISNODE->id, seqno); 641 encode_header (enc, THISNODE->id, seqno);
… …
593 encp += lbllen; 659 encp += lbllen;
594 660
595 enclen -= lbllen; 661 enclen -= lbllen;
596 } 662 }
597 663
598 append_domain (*pkt, offs, THISNODE->domain); 664 append_domain (*pkt, offs, dns->c->conf->domain);
599 665
600 (*pkt)[offs++] = 0; 666 (*pkt)[offs++] = 0;
601 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 667 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
602 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 668 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
603 669
604 pkt->len = offs; 670 pkt->len = offs;
605} 671}
606 672
607void dns_snd::gen_syn_req (const dns_cfg &cfg) 673void dns_snd::gen_syn_req ()
608{ 674{
609 timeout = NOW + INITIAL_SYN_TIMEOUT; 675 timeout = NOW + INITIAL_SYN_TIMEOUT;
610 676
611 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 677 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
612 pkt->qdcount = htons (1); 678 pkt->qdcount = htons (1);
613 679
614 int offs = 6*2; 680 int offs = 6 * 2;
615 681
616 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); 682 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg));
617 683
618 assert (elen <= MAX_LBL_SIZE); 684 assert (elen <= MAX_LBL_SIZE);
619 685
620 (*pkt)[offs] = elen; 686 (*pkt)[offs] = elen;
621 offs += elen + 1; 687 offs += elen + 1;
622 append_domain (*pkt, offs, THISNODE->domain); 688 append_domain (*pkt, offs, dns->c->conf->domain);
623 689
624 (*pkt)[offs++] = 0; 690 (*pkt)[offs++] = 0;
625 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 691 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
626 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 692 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
627 693
… …
650 delete pkt; 716 delete pkt;
651} 717}
652 718
653///////////////////////////////////////////////////////////////////////////// 719/////////////////////////////////////////////////////////////////////////////
654 720
655struct dns_connection
656{
657 connection *c;
658 struct vpn *vpn;
659
660 dns_cfg cfg;
661
662 bool established;
663
664 tstamp last_received;
665 tstamp last_sent;
666 double poll_interval, send_interval;
667
668 vector<dns_rcv *> rcvpq;
669
670 byte_stream rcvdq; int rcvseq;
671 byte_stream snddq; int sndseq;
672
673 void time_cb (time_watcher &w); time_watcher tw;
674 void receive_rep (dns_rcv *r);
675
676 dns_connection (connection *c);
677 ~dns_connection ();
678};
679
680dns_connection::dns_connection (connection *c) 721dns_connection::dns_connection (connection *c)
681: c (c) 722: c (c)
682, rcvdq (MAX_BACKLOG * 2) 723, rcvdq (MAX_BACKLOG * 2)
683, snddq (MAX_BACKLOG * 2) 724, snddq (MAX_BACKLOG * 2)
684, tw (this, &dns_connection::time_cb) 725, tw (this, &dns_connection::time_cb)
… …
689 730
690 rcvseq = sndseq = 0; 731 rcvseq = sndseq = 0;
691 732
692 last_sent = last_received = 0; 733 last_sent = last_received = 0;
693 poll_interval = MIN_POLL_INTERVAL; 734 poll_interval = MIN_POLL_INTERVAL;
694 send_interval = 0.2; // starting rate 735 send_interval = 0.5; // starting rate
736 last_latency = INITIAL_TIMEOUT;
695} 737}
696 738
697dns_connection::~dns_connection () 739dns_connection::~dns_connection ()
698{ 740{
699 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 741 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
… …
707 if (r->datalen) 749 if (r->datalen)
708 { 750 {
709 last_received = NOW; 751 last_received = NOW;
710 tw.trigger (); 752 tw.trigger ();
711 753
712 poll_interval *= 0.99; 754 poll_interval = send_interval;
713 if (poll_interval > MIN_POLL_INTERVAL)
714 poll_interval = MIN_POLL_INTERVAL;
715 } 755 }
716 else 756 else
717 { 757 {
718 poll_interval *= 1.1; 758 poll_interval *= 1.5;
719 if (poll_interval > MAX_POLL_INTERVAL) 759 if (poll_interval > MAX_POLL_INTERVAL)
720 poll_interval = MAX_POLL_INTERVAL; 760 poll_interval = MAX_POLL_INTERVAL;
721 } 761 }
722 762
723 rcvpq.push_back (r); 763 rcvpq.push_back (r);
… …
741 } 781 }
742 782
743 rcvseq = (rcvseq + 1) & SEQNO_MASK; 783 rcvseq = (rcvseq + 1) & SEQNO_MASK;
744 784
745 if (!rcvdq.put (r->data, r->datalen)) 785 if (!rcvdq.put (r->data, r->datalen))
786 {
787 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
746 abort (); // MUST never overflow, can be caused by data corruption, TODO 788 abort (); // MUST never overflow, can be caused by data corruption, TODO
789 }
747 790
748 while (vpn_packet *pkt = rcvdq.get ()) 791 while (vpn_packet *pkt = rcvdq.get ())
749 { 792 {
750 sockinfo si; 793 sockinfo si;
751 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 794 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4;
752 795
753 vpn->recv_vpn_packet (pkt, si); 796 vpn->recv_vpn_packet (pkt, si);
797
798 delete pkt;
754 } 799 }
755 800
756 // check for further packets 801 // check for further packets
757 goto redo; 802 goto redo;
758 } 803 }
… …
768 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 813 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
769 814
770 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 815 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
771 && pkt.qdcount == htons (1)) 816 && pkt.qdcount == htons (1))
772 { 817 {
773 char qname[MAXSIZE]; 818 char qname [MAXSIZE];
774 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 819 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
775 820
776 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 821 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
777 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 822 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
778 823
779 pkt.qdcount = htons (1); 824 pkt.qdcount = htons (1);
780 pkt.ancount = 0; 825 pkt.ancount = 0;
781 pkt.nscount = 0; // should be self, as other nameservers reply like this 826 pkt.nscount = 0; // should be self, as other nameservers reply like this
782 pkt.arcount = 0; // a record for self, as other nameservers reply like this 827 pkt.arcount = 0; // a record for self, as other nameservers reply like this
783 828
784 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_NXDOMAIN); 829 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_SERVFAIL);
785 830
786 int dlen = strlen (THISNODE->domain); 831 int dlen = strlen (THISNODE->domain);
787 832
788 if (qclass == RR_CLASS_IN 833 if (qclass == RR_CLASS_IN
789 && qlen > dlen + 1 834 && qlen > dlen + 1
790 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 835 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
791 { 836 {
792 // now generate reply 837 // now generate reply
793 pkt.ancount = htons (1); // one answer RR 838 pkt.ancount = htons (1); // one answer RR
794 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 839 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
795 840
… …
808 if (0 < client && client <= conns.size ()) 853 if (0 < client && client <= conns.size ())
809 { 854 {
810 connection *c = conns [client - 1]; 855 connection *c = conns [client - 1];
811 dns_connection *dns = c->dns; 856 dns_connection *dns = c->dns;
812 dns_rcv *rcv; 857 dns_rcv *rcv;
858 bool in_seq;
813 859
814 if (dns) 860 if (dns)
815 { 861 {
816 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 862 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
817 if (SEQNO_EQ ((*i)->seqno, seqno)) 863 if (SEQNO_EQ ((*i)->seqno, seqno))
818 { 864 {
819 // already seen that request: simply reply with the cached reply 865 // already seen that request: simply reply with the cached reply
820 dns_rcv *r = *i; 866 dns_rcv *r = *i;
821 867
822 printf ("DUPLICATE %d\n", htons (r->pkt->id));//D 868 slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
869
870 // refresh header & id, as the retry count could have changed
871 memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
872 r->pkt->id = pkt.id;
823 873
824 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 874 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
825 pkt.id = r->pkt->id; 875
826 goto duplicate_request; 876 goto duplicate_request;
827 } 877 }
878
879 in_seq = dns->rcvseq == seqno;
828 880
829 // new packet, queue 881 // new packet, queue
830 rcv = new dns_rcv (seqno, data, datalen); 882 rcv = new dns_rcv (seqno, data, datalen);
831 dns->receive_rep (rcv); 883 dns->receive_rep (rcv);
832 } 884 }
833 885
886 {
834 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 887 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
835 888
836 // type
837 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 889 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
838 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; 890 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
839
840 // class
841 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; 891 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
842
843 // TTL
844 pkt [offs++] = 0; pkt [offs++] = 0; 892 pkt [offs++] = 0; pkt [offs++] = 0;
845 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; 893 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
846 894
847 int rdlen_offs = offs += 2; 895 int rdlen_offs = offs += 2;
848 896
849 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 897 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
850 // bind doesn't compress well, so reduce further by one label length 898 // bind doesn't compress well, so reduce further by one label length
851 dlen -= qlen; 899 dlen -= qlen;
852 900
853 if (dns) 901 if (dns)
854 { 902 {
903 // only put data into in-order sequence packets, if
904 // we receive out-of-order packets we generate empty
905 // replies
855 while (dlen > 1 && !dns->snddq.empty ()) 906 while (dlen > 1 && !dns->snddq.empty () && in_seq)
856 { 907 {
857 int txtlen = dlen <= 255 ? dlen - 1 : 255; 908 int txtlen = dlen <= 255 ? dlen - 1 : 255;
858 909
859 if (txtlen > dns->snddq.size ()) 910 if (txtlen > dns->snddq.size ())
860 txtlen = dns->snddq.size (); 911 txtlen = dns->snddq.size ();
861 912
862 pkt[offs++] = txtlen; 913 pkt[offs++] = txtlen;
863 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 914 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
864 offs += txtlen; 915 offs += txtlen;
865 dns->snddq.remove (txtlen); 916 dns->snddq.remove (txtlen);
866 917
867 dlen -= txtlen + 1; 918 dlen -= txtlen + 1;
868 } 919 }
869 920
870 // avoid empty TXT rdata 921 // avoid empty TXT rdata
871 if (offs == rdlen_offs) 922 if (offs == rdlen_offs)
872 pkt[offs++] = 0; 923 pkt[offs++] = 0;
924
925 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
873 } 926 }
874 else 927 else
875 { 928 {
876 // send RST 929 // send RST
877 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 930 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
878 pkt [offs++] = CMD_IP_RST; 931 pkt [offs++] = CMD_IP_RST;
879 } 932 }
880 933
881 int rdlen = offs - rdlen_offs; 934 int rdlen = offs - rdlen_offs;
882 935
883 pkt [rdlen_offs - 2] = rdlen >> 8; 936 pkt [rdlen_offs - 2] = rdlen >> 8;
884 pkt [rdlen_offs - 1] = rdlen; 937 pkt [rdlen_offs - 1] = rdlen;
885 938
886 if (dns) 939 if (dns)
887 { 940 {
888 // now update dns_rcv copy 941 // now update dns_rcv copy
889 rcv->pkt->len = offs; 942 rcv->pkt->len = offs;
890 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 943 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
891 } 944 }
945 }
892 946
893 duplicate_request: ; 947 duplicate_request: ;
894 } 948 }
895 else 949 else
896 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 950 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
908 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 962 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
909 pkt [offs++] = 0; pkt [offs++] = 0; 963 pkt [offs++] = 0; pkt [offs++] = 0;
910 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 964 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
911 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 965 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
912 966
913 slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client); 967 slog (L_INFO, _("DNS: client %d connects"), client);
914 968
915 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 969 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
916 pkt [offs++] = CMD_IP_REJ; 970 pkt [offs++] = CMD_IP_REJ;
917 971
918 if (0 < client && client <= conns.size ()) 972 if (0 < client && client <= conns.size ())
… …
949 i != dns_sndpq.end (); 1003 i != dns_sndpq.end ();
950 ++i) 1004 ++i)
951 if ((*i)->pkt->id == pkt.id) 1005 if ((*i)->pkt->id == pkt.id)
952 { 1006 {
953 dns_connection *dns = (*i)->dns; 1007 dns_connection *dns = (*i)->dns;
1008 connection *c = dns->c;
954 int seqno = (*i)->seqno; 1009 int seqno = (*i)->seqno;
955 u8 data[MAXSIZE], *datap = data; 1010 u8 data[MAXSIZE], *datap = data;
956 1011
957 if ((*i)->retry) 1012 if ((*i)->retry)
958 { 1013 {
959 dns->send_interval *= 1.01; 1014 dns->send_interval *= 1.01;
960 if (dns->send_interval < MAX_SEND_INTERVAL) 1015 if (dns->send_interval > MAX_SEND_INTERVAL)
961 dns->send_interval = MAX_SEND_INTERVAL; 1016 dns->send_interval = MAX_SEND_INTERVAL;
962 } 1017 }
963 else 1018 else
964 { 1019 {
1020#if 1
965 dns->send_interval *= 0.99; 1021 dns->send_interval *= 0.999;
1022#endif
966 if (dns->send_interval < MIN_SEND_INTERVAL) 1023 if (dns->send_interval < MIN_SEND_INTERVAL)
967 dns->send_interval = MIN_SEND_INTERVAL; 1024 dns->send_interval = MIN_SEND_INTERVAL;
968 1025
969 // the latency surely puts an upper bound on 1026 // the latency surely puts an upper bound on
970 // the minimum send interval 1027 // the minimum send interval
1028 double latency = NOW - (*i)->sent;
1029 dns->last_latency = latency;
1030
971 if (dns->send_interval > NOW - (*i)->sent) 1031 if (dns->send_interval > latency)
972 dns->send_interval = NOW - (*i)->sent; 1032 dns->send_interval = latency;
973 } 1033 }
974 1034
975 delete *i; 1035 delete *i;
976 dns_sndpq.erase (i); 1036 dns_sndpq.erase (i);
977 1037
… …
1027 1087
1028 if (ip [0] == CMD_IP_1 1088 if (ip [0] == CMD_IP_1
1029 && ip [1] == CMD_IP_2 1089 && ip [1] == CMD_IP_2
1030 && ip [2] == CMD_IP_3) 1090 && ip [2] == CMD_IP_3)
1031 { 1091 {
1032 slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]); 1092 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1033 1093
1034 if (ip [3] == CMD_IP_RST) 1094 if (ip [3] == CMD_IP_RST)
1035 { 1095 {
1036 slog (L_DEBUG, _("got tunnel RST request")); 1096 slog (L_DEBUG, _("DNS: got tunnel RST request"));
1037 1097
1038 connection *c = dns->c;
1039 delete c->dns; c->dns = 0; 1098 delete dns; c->dns = 0;
1040 1099
1041 return; 1100 return;
1042 } 1101 }
1043 else if (ip [3] == CMD_IP_SYN) 1102 else if (ip [3] == CMD_IP_SYN)
1103 {
1104 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1044 dns->established = true; 1105 dns->established = true;
1106 }
1107 else if (ip [3] == CMD_IP_REJ)
1108 {
1109 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
1110 abort ();
1111 }
1045 else 1112 else
1046 slog (L_INFO, _("got unknown meta command %02x"), ip [3]); 1113 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1047 } 1114 }
1048 else 1115 else
1049 slog (L_INFO, _("got spurious a record %d.%d.%d.%d"), 1116 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1050 ip [0], ip [1], ip [2], ip [3]); 1117 ip [0], ip [1], ip [2], ip [3]);
1051 1118
1052 return; 1119 return;
1053 } 1120 }
1054 1121
1055 int client, rseqno; 1122 int client, rseqno;
1056 decode_header (qname, client, rseqno); 1123 decode_header (qname, client, rseqno);
1057 1124
1058 if (client != THISNODE->id) 1125 if (client != THISNODE->id)
1059 { 1126 {
1060 slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring")); 1127 slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1061 datap = 0; 1128 datap = 0;
1062 } 1129 }
1063 else if (rseqno != seqno) 1130 else if (rseqno != seqno)
1064 { 1131 {
1065 slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?")); 1132 slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
1066 datap = 0; 1133 datap = 0;
1067 } 1134 }
1068 } 1135 }
1069 } 1136 }
1070 1137
… …
1087 1154
1088 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1155 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1089 1156
1090 if (pkt->len > 0) 1157 if (pkt->len > 0)
1091 { 1158 {
1092 if (THISNODE->dns_port) 1159 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1160 dnsv4_client (*pkt);
1161 else
1093 { 1162 {
1094 dnsv4_server (*pkt); 1163 dnsv4_server (*pkt);
1095 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1164 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1096 } 1165 }
1097 else
1098 dnsv4_client (*pkt);
1099 1166
1100 delete pkt; 1167 delete pkt;
1101 } 1168 }
1102 } 1169 }
1103} 1170}
1104 1171
1105bool 1172bool
1106connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1173vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1107{ 1174{
1175 int client = ntohs (si.port);
1176
1177 assert (0 < client && client <= conns.size ());
1178
1179 connection *c = conns [client - 1];
1180
1108 if (!dns) 1181 if (!c->dns)
1109 dns = new dns_connection (this); 1182 c->dns = new dns_connection (c);
1110 1183
1111 if (!dns->snddq.put (pkt)) 1184 if (!c->dns->snddq.put (pkt))
1112 return false; 1185 return false;
1113 1186
1114 dns->tw.trigger (); 1187 c->dns->tw.trigger ();
1115 1188
1116 return true; 1189 return true;
1190}
1191
1192void
1193connection::dnsv4_reset_connection ()
1194{
1195 //delete dns; dns = 0; //TODO
1117} 1196}
1118 1197
1119#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1198#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1120 1199
1121void 1200void
… …
1140 if (!send) 1219 if (!send)
1141 { 1220 {
1142 send = r; 1221 send = r;
1143 1222
1144 r->retry++; 1223 r->retry++;
1145 r->timeout = NOW + r->retry; 1224 r->timeout = NOW + (r->retry * last_latency * 8.);
1225
1226 // the following code changes the query section a bit, forcing
1227 // the forwarder to generate a new request
1228 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);
1232 }
1146 } 1233 }
1147 } 1234 }
1148 else if (r->timeout < next) 1235 else
1149 NEXT (r->timeout); 1236 NEXT (r->timeout);
1150 } 1237 }
1151 1238
1152 if (last_sent + send_interval <= NOW) 1239 if (last_sent + send_interval <= NOW)
1153 { 1240 {
… …
1160 if (vpn->dns_sndpq.empty ()) 1247 if (vpn->dns_sndpq.empty ())
1161 { 1248 {
1162 send = new dns_snd (this); 1249 send = new dns_snd (this);
1163 1250
1164 cfg.reset (THISNODE->id); 1251 cfg.reset (THISNODE->id);
1165 send->gen_syn_req (cfg); 1252 send->gen_syn_req ();
1166 } 1253 }
1167 } 1254 }
1168 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING) 1255 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
1256 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1169 { 1257 {
1258 //printf ("sending data request etc.\n"); //D
1259 if (!snddq.empty ())
1260 {
1261 poll_interval = send_interval;
1262 NEXT (NOW + send_interval);
1263 }
1264
1170 send = new dns_snd (this); 1265 send = new dns_snd (this);
1171 send->gen_stream_req (sndseq, snddq); 1266 send->gen_stream_req (sndseq, snddq);
1267 send->timeout = NOW + last_latency * 8.;
1172 1268
1173 sndseq = (sndseq + 1) & SEQNO_MASK; 1269 sndseq = (sndseq + 1) & SEQNO_MASK;
1174 } 1270 }
1175 1271
1176 if (send) 1272 if (send)
1177 vpn->dns_sndpq.push_back (send); 1273 vpn->dns_sndpq.push_back (send);
1178 } 1274 }
1179 1275
1180 if (send) 1276 if (send)
1181 { 1277 {
1182 printf ("send pkt\n");
1183 last_sent = NOW; 1278 last_sent = NOW;
1184
1185 if (!send->retry)
1186 send->sent = NOW;
1187
1188 sendto (vpn->dnsv4_fd, 1279 sendto (vpn->dnsv4_fd,
1189 send->pkt->at (0), send->pkt->len, 0, 1280 send->pkt->at (0), send->pkt->len, 0,
1190 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1281 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1191 } 1282 }
1192 } 1283 }
1193 else 1284 else
1194 NEXT (last_sent + send_interval); 1285 NEXT (last_sent + send_interval);
1195 1286
1196 printf ("pi %f si %f N %f (%d:%d)\n", poll_interval, send_interval, next - NOW, vpn->dns_sndpq.size (), snddq.size ()); 1287 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)",
1288 poll_interval, send_interval, next - NOW,
1289 vpn->dns_sndpq.size (), snddq.size ());
1290
1291 // TODO: no idea when this happens, but when next < NOW, we have a problem
1292 if (next < NOW + 0.0001)
1293 next = NOW + 0.1;
1197 1294
1198 w.start (next); 1295 w.start (next);
1199} 1296}
1200 1297
1201#endif 1298#endif

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