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/cvs/gvpe/src/vpn_dns.C
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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.5 by pcg, Thu Mar 3 07:24:57 2005 UTC vs.
Revision 1.6 by pcg, Thu Mar 3 08:38:32 2005 UTC

… …
51 51
52#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well 52#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well
53// 240 leaves about 4 bytes of server reply data 53// 240 leaves about 4 bytes of server reply data
54// every two request byte sless give room for one reply byte 54// every two request byte sless give room for one reply byte
55 55
56// seqno has 12 bits, but the lower bit is always left as zero
57// as bind caches ttl=0 records and we have to generate
58// sequence numbers that always differ case-insensitively
56#define SEQNO_MASK 0xffff 59#define SEQNO_MASK 0x07ff
57 60
58/* 61/*
59 62
60protocol, in shorthand :) 63protocol, in shorthand :)
61 64
… …
90 static int decode (u8 *dst, char *src, int len); 93 static int decode (u8 *dst, char *src, int len);
91 94
92 dns64 (); 95 dns64 ();
93} dns64; 96} dns64;
94 97
95const char dns64::encode_chars[64 + 1] = "_4B9dLphHzrqQmGjkTbJt5svlZX8xSaReEYfwKgF1DP2W6NyVOU70IouACcMn3i-"; 98// the following sequence has been crafted to
99// a) look somewhat random
100// b) the even (and odd) indices never share the same character as upper/lowercase
101const char dns64::encode_chars[64 + 1] = "_-dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI";
96s8 dns64::decode_chars[256]; 102s8 dns64::decode_chars[256];
97 103
98dns64::dns64 () 104dns64::dns64 ()
99{ 105{
100 for (int i = 0; i < 64; i++) 106 for (int i = 0; i < 64; i++)
… …
218} 224}
219 225
220vpn_packet *byte_stream::get () 226vpn_packet *byte_stream::get ()
221{ 227{
222 int len = (data [0] << 8) | data [1]; 228 int len = (data [0] << 8) | data [1];
223
224 printf ("get len %d, fill %d\n", len, fill);//D
225 229
226 if (len > MAXSIZE && fill >= 2) 230 if (len > MAXSIZE && fill >= 2)
227 abort (); // TODO handle this gracefully, connection reset 231 abort (); // TODO handle this gracefully, connection reset
228 232
229 if (fill < len + 2) 233 if (fill < len + 2)
… …
356 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 360 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
357 361
358 u8 data[256]; //TODO 362 u8 data[256]; //TODO
359 363
360 data[0] = THISNODE->id; //TODO 364 data[0] = THISNODE->id; //TODO
361 data[1] = seqno >> 8; //TODO 365 data[1] = seqno >> 7; //TODO
362 data[2] = seqno; //TODO 366 data[2] = seqno << 1; //TODO
363 367
364 int datalen = dns64::decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE) - 3; 368 int datalen = dns64::decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE) - 3;
365 369
366 if (datalen > stream->size ()) 370 if (datalen > stream->size ())
367 datalen = stream->size (); 371 datalen = stream->size ();
… …
419 int seqno; 423 int seqno;
420 dns_packet *pkt; // reply packet 424 dns_packet *pkt; // reply packet
421 u8 data [MAXSIZE]; // actually part of the reply packet... 425 u8 data [MAXSIZE]; // actually part of the reply packet...
422 int datalen; 426 int datalen;
423 427
424 dns_rcv (int seqno, dns_packet *req, u8 *data, int datalen); 428 dns_rcv (int seqno, u8 *data, int datalen);
425 ~dns_rcv (); 429 ~dns_rcv ();
426}; 430};
427 431
428dns_rcv::dns_rcv (int seqno, dns_packet *req, u8 *data, int datalen) 432dns_rcv::dns_rcv (int seqno, u8 *data, int datalen)
429: seqno (seqno), pkt (new dns_packet), datalen (datalen) 433: seqno (seqno), pkt (new dns_packet), datalen (datalen)
430{ 434{
431 memcpy (this->data, data, datalen); 435 memcpy (this->data, data, datalen);
432 pkt->len = req->len;
433 memcpy (pkt->at (0), req->at (0), req->len);
434} 436}
435 437
436dns_rcv::~dns_rcv () 438dns_rcv::~dns_rcv ()
437{ 439{
438 delete pkt; 440 delete pkt;
… …
481 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 483 si.host = 0; si.port = 0; si.prot = PROT_DNSv4;
482 484
483 vpn->recv_vpn_packet (pkt, si); 485 vpn->recv_vpn_packet (pkt, si);
484 } 486 }
485 } 487 }
486 else if ((u32)dns_rcvseq - MAX_WINDOW - (u32)(*i)->seqno < MAX_WINDOW * 2) 488 else if ((u32)(*i)->seqno - (u32)dns_rcvseq + MAX_WINDOW > MAX_WINDOW * 2)
487 { 489 {
490 //D
491 //abort();
492 printf ("%d erasing %d (%d)\n", THISNODE->id, (u32)(*i)->seqno, dns_rcvseq);
488 dns_rcvpq.erase (i); 493 dns_rcvpq.erase (i);
489 goto redo; 494 goto redo;
490 } 495 }
491} 496}
492 497
… …
526 // correct class, domain: parse 531 // correct class, domain: parse
527 u8 data[MAXSIZE]; 532 u8 data[MAXSIZE];
528 int datalen = dns64::decode (data, qname, qlen - dlen - 1); 533 int datalen = dns64::decode (data, qname, qlen - dlen - 1);
529 534
530 int client = data[0]; 535 int client = data[0];
531 int seqno = ((data[1] << 8) | data[2]) & SEQNO_MASK; 536 int seqno = ((data[1] << 7) | (data[2] >> 1)) & SEQNO_MASK;
532 537
533 if (0 < client && client <= conns.size ()) 538 if (0 < client && client <= conns.size ())
534 { 539 {
535 connection *c = conns [client - 1]; 540 connection *c = conns [client - 1];
541
542 redo:
536 543
537 for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.begin (); 544 for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.begin ();
538 i != c->dns_rcvpq.end (); 545 i != c->dns_rcvpq.end ();
539 ++i) 546 ++i)
540 if ((*i)->seqno == seqno) 547 if ((*i)->seqno == seqno)
541 { 548 {
542 // already seen that request, just reply with the original reply 549 // already seen that request: simply reply with the cached reply
543 dns_rcv *r = *i; 550 dns_rcv *r = *i;
551
552 printf ("DUPLICATE %d\n", htons (r->pkt->id));//D
544 553
545 offs = r->pkt->len; 554 offs = r->pkt->len;
546 memcpy (pkt->at (0), r->pkt->at (0), offs); 555 memcpy (pkt->at (0), r->pkt->at (0), offs);
547 goto duplicate_request; 556 goto duplicate_request;
548 } 557 }
549 558
550 // new packet, queue 559 // new packet, queue
551 c->dnsv4_receive_rep (new dns_rcv (seqno, pkt, data + 3, datalen - 3)); 560 dns_rcv *rcv = new dns_rcv (seqno, data + 3, datalen - 3);
561 c->dnsv4_receive_rep (rcv);
552 562
553 // now generate reply 563 // now generate reply
554 pkt->ancount = htons (1); // one answer RR 564 pkt->ancount = htons (1); // one answer RR
555 pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 565 pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
556 566
… …
594 int rdlen = offs - rdlen_offs; 604 int rdlen = offs - rdlen_offs;
595 605
596 (*pkt) [rdlen_offs - 2] = rdlen >> 8; 606 (*pkt) [rdlen_offs - 2] = rdlen >> 8;
597 (*pkt) [rdlen_offs - 1] = rdlen; 607 (*pkt) [rdlen_offs - 1] = rdlen;
598 608
609 // now update dns_rcv copy
610 rcv->pkt->len = offs;
611 memcpy (rcv->pkt->at (0), pkt->at (0), offs);
612
599 duplicate_request: ; 613 duplicate_request: ;
600 } 614 }
601 else 615 else
602 pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 616 pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
603 } 617 }
604 }
605 else
606 offs = pkt->len;
607 618
608 pkt->len = offs; 619 pkt->len = offs;
620 }
621
609 return pkt; 622 return pkt;
610} 623}
611 624
612void 625void
613vpn::dnsv4_client (dns_packet *pkt) 626vpn::dnsv4_client (dns_packet *pkt)
… …
673 } 686 }
674 687
675 } 688 }
676 } 689 }
677 690
678 if (datap != data) 691 // todo: pkt now used
679 printf ("%02x %02x %02x %02x\n",
680 data[0],
681 data[1],
682 data[2],
683 data[3]);
684
685 printf ("recv %d,%d\n", pkt->id, seqno, datap - data);//D
686 c->dnsv4_receive_rep (new dns_rcv (seqno, pkt, data, datap - data)); 692 c->dnsv4_receive_rep (new dns_rcv (seqno, data, datap - data));
687 693
688 break; 694 break;
689 } 695 }
690 696
691 delete pkt; 697 delete pkt;

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