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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs.
Revision 1.46 by pcg, Thu Dec 6 00:35:29 2007 UTC

14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details. 15 GNU General 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
18 along with gvpe; if not, write to the Free Software 18 along with gvpe; if not, write to the Free Software
19 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20*/ 20*/
21
22// TODO: EDNS0 option to increase dns mtu?
23// TODO: re-write dns packet parsing/creation using a safe mem-buffer
24// to ensure no buffer overflows or similar problems.
21 25
22#include "config.h" 26#include "config.h"
23 27
24#if ENABLE_DNS 28#if ENABLE_DNS
25 29
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 30// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27// it's a hack, use only in emergency situations please. 31// it's a hack, use only in emergency situations please.
28 32
29#include <cstring> 33#include <cstring>
34#include <cassert>
30 35
31#include <sys/types.h> 36#include <sys/types.h>
32#include <sys/socket.h> 37#include <sys/socket.h>
33#include <sys/wait.h> 38#include <sys/wait.h>
34#include <sys/uio.h> 39#include <sys/uio.h>
37#include <unistd.h> 42#include <unistd.h>
38#include <fcntl.h> 43#include <fcntl.h>
39 44
40#include <map> 45#include <map>
41 46
47#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
42#include <gmp.h> 48#include <gmp.h>
43 49
44#include "netcompat.h" 50#include "netcompat.h"
45 51
46#include "vpn.h" 52#include "vpn.h"
47 53
48#define MIN_RETRY 1. 54#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
49#define MAX_RETRY 6. 55#define ACTIVITY_INTERVAL 5.
50 56
51#define MAX_OUTSTANDING 400 // max. outstanding requests 57#define INITIAL_TIMEOUT 0.1 // retry timeouts
58#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
59
60#define MAX_SEND_INTERVAL 2. // optimistic?
61
52#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING 62#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
53#define MAX_RATE 100 // requests/s
54#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE 63#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55 64
56#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well 65#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well
57// 240 leaves about 4 bytes of server reply data 66// 240 leaves about 4 bytes of server reply data
58// every two request byte sless give room for one reply byte 67// every request byte less give room for two reply bytes
59 68
60#define SEQNO_MASK 0xffff 69#define SEQNO_MASK 0x3fff
61#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 70#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
62 71
63#define MAX_LBL_SIZE 63 72#define MAX_LBL_SIZE 63
64#define MAX_PKT_SIZE 512 73#define MAX_PKT_SIZE 512
65 74
75#define RR_TYPE_A 1
76#define RR_TYPE_NULL 10
66#define RR_TYPE_TXT 16 77#define RR_TYPE_TXT 16
67#define RR_TYPE_ANY 255 78#define RR_TYPE_ANY 255
79
68#define RR_CLASS_IN 1 80#define RR_CLASS_IN 1
81
82#define CMD_IP_1 207
83#define CMD_IP_2 46
84#define CMD_IP_3 236
85#define CMD_IP_RST 29
86#define CMD_IP_SYN 113
87#define CMD_IP_REJ 32
69 88
70// works for cmaps up to 255 (not 256!) 89// works for cmaps up to 255 (not 256!)
71struct charmap 90struct charmap
72{ 91{
73 enum { INVALID = (u8)255 }; 92 enum { INVALID = (u8)255 };
153 return dec_len [len]; 172 return dec_len [len];
154} 173}
155 174
156unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 175unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len)
157{ 176{
158 if (!len) 177 if (!len || len > MAX_DEC_LEN)
159 return 0; 178 return 0;
160 179
161 int elen = encode_len (len); 180 int elen = encode_len (len);
162 181
163 mp_limb_t m [MAX_LIMBS]; 182 mp_limb_t m [MAX_LIMBS];
182 return elen; 201 return elen;
183} 202}
184 203
185unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 204unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len)
186{ 205{
187 if (!len) 206 if (!len || len > MAX_ENC_LEN)
188 return 0; 207 return 0;
189 208
190 u8 src_ [MAX_ENC_LEN]; 209 u8 src_ [MAX_ENC_LEN];
191 unsigned int elen = 0; 210 unsigned int elen = 0;
192 211
239 } 258 }
240 abort (); 259 abort ();
241} 260}
242#endif 261#endif
243 262
244// the following sequence has been crafted to 263//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
245// a) look somewhat random
246// b) the even (and odd) indices never share the same character as upper/lowercase
247// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)
248// the other sequences are obviously derived
249//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 264//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
250static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 265static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 266//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
252static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 267static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
253 268
254///////////////////////////////////////////////////////////////////////////// 269/////////////////////////////////////////////////////////////////////////////
255 270
256#define HDRSIZE 6 271#define HDRSIZE 6
257 272
258inline void encode_header (char *data, int clientid, int seqno) 273inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
259{ 274{
260 u8 hdr[3] = { clientid, seqno >> 8, seqno }; 275 seqno &= SEQNO_MASK;
276
277 u8 hdr[3] = {
278 clientid,
279 (seqno >> 8) | (retry << 6),
280 seqno,
281 };
261 282
262 assert (clientid < 256); 283 assert (clientid < 256);
263 284
264 cdc26.encode (data, hdr, 3); 285 cdc26.encode (data, hdr, 3);
265} 286}
269 u8 hdr[3]; 290 u8 hdr[3];
270 291
271 cdc26.decode (hdr, data, HDRSIZE); 292 cdc26.decode (hdr, data, HDRSIZE);
272 293
273 clientid = hdr[0]; 294 clientid = hdr[0];
274 seqno = (hdr[1] << 8) | hdr[2]; 295 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK;
275} 296}
276 297
277///////////////////////////////////////////////////////////////////////////// 298/////////////////////////////////////////////////////////////////////////////
278 299
279struct byte_stream 300struct byte_stream
308} 329}
309 330
310void byte_stream::remove (int count) 331void byte_stream::remove (int count)
311{ 332{
312 if (count > fill) 333 if (count > fill)
313 abort (); 334 assert (count <= fill);
314 335
315 memmove (data, data + count, fill -= count); 336 memmove (data, data + count, fill -= count);
316} 337}
317 338
318bool byte_stream::put (u8 *data, unsigned int datalen) 339bool byte_stream::put (u8 *data, unsigned int datalen)
331 return false; 352 return false;
332 353
333 data [fill++] = pkt->len >> 8; 354 data [fill++] = pkt->len >> 8;
334 data [fill++] = pkt->len; 355 data [fill++] = pkt->len;
335 356
336 memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len; 357 memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
337 358
338 return true; 359 return true;
339} 360}
340 361
341vpn_packet *byte_stream::get () 362vpn_packet *byte_stream::get ()
342{ 363{
364 unsigned int len;
365
366 for (;;)
367 {
343 int len = (data [0] << 8) | data [1]; 368 len = (data [0] << 8) | data [1];
344 369
345 if (len > MAXSIZE && fill >= 2) 370 if (len <= MAXSIZE || fill < 2)
346 abort (); // TODO handle this gracefully, connection reset 371 break;
347 372
373 // TODO: handle this better than skipping, e.g. by reset
374 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
375 remove (1);
376 }
377
348 if (fill < len + 2) 378 if (fill < len + 2)
349 return 0; 379 return 0;
350 380
351 vpn_packet *pkt = new vpn_packet; 381 vpn_packet *pkt = new vpn_packet;
352 382
353 pkt->len = len; 383 pkt->len = len;
354 memcpy (&((*pkt)[0]), data + 2, len); 384 memcpy (pkt->at (0), data + 2, len);
355 remove (len + 2); 385 remove (len + 2);
356 386
357 return pkt; 387 return pkt;
358} 388}
359 389
376#define FLAG_RCODE_REFUSED ( 5 << 0) 406#define FLAG_RCODE_REFUSED ( 5 << 0)
377 407
378#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY | FLAG_OP_QUERY | FLAG_RD) 408#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY | FLAG_OP_QUERY | FLAG_RD)
379#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE | FLAG_OP_QUERY | FLAG_AA | FLAG_RD | FLAG_RA) 409#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE | FLAG_OP_QUERY | FLAG_AA | FLAG_RD | FLAG_RA)
380 410
411struct dns_cfg
412{
413 static int next_uid;
414
415 u8 id1, id2, id3, id4;
416
417 u8 version;
418 u8 flags;
419 u8 rrtype;
420 u8 def_ttl;
421
422 u16 client;
423 u16 uid; // to make request unique
424
425 u16 max_size;
426 u8 seq_cdc;
427 u8 req_cdc;
428
429 u8 rep_cdc;
430 u8 delay; // time in 0.01s units that the server may delay replying packets
431 u8 r3, r4;
432
433 u8 r5, r6, r7, r8;
434
435 void reset (int clientid);
436 bool valid ();
437};
438
439int dns_cfg::next_uid;
440
441void dns_cfg::reset (int clientid)
442{
443 id1 = 'G';
444 id2 = 'V';
445 id3 = 'P';
446 id4 = 'E';
447
448 version = 1;
449
450 rrtype = RR_TYPE_TXT;
451 flags = 0;
452 def_ttl = 0;
453 seq_cdc = 26;
454 req_cdc = 62;
455 rep_cdc = 0;
456 max_size = htons (MAX_PKT_SIZE);
457 client = htons (clientid);
458 uid = next_uid++;
459 delay = 0;
460
461 r3 = r4 = 0;
462 r4 = r5 = r6 = r7 = 0;
463}
464
465bool dns_cfg::valid ()
466{
467 // although the protocol itself allows for some configurability,
468 // only the following encoding/decoding settings are implemented.
469 return id1 == 'G'
470 && id2 == 'V'
471 && id3 == 'P'
472 && id4 == 'E'
473 && seq_cdc == 26
474 && req_cdc == 62
475 && rep_cdc == 0
476 && version == 1;
477}
478
381struct dns_packet : net_packet 479struct dns_packet : net_packet
382{ 480{
383 u16 id; 481 u16 id;
384 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 482 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
385 u16 qdcount, ancount, nscount, arcount; 483 u16 qdcount, ancount, nscount, arcount;
386 484
387 u8 data[MAXSIZE - 6 * 2]; 485 u8 data [MAXSIZE - 6 * 2];
388 486
389 int decode_label (char *data, int size, int &offs); 487 int decode_label (char *data, int size, int &offs);
390}; 488};
391 489
392int dns_packet::decode_label (char *data, int size, int &offs) 490int dns_packet::decode_label (char *data, int size, int &offs)
423 return data - orig; 521 return data - orig;
424} 522}
425 523
426///////////////////////////////////////////////////////////////////////////// 524/////////////////////////////////////////////////////////////////////////////
427 525
428struct dns_req
429{
430 dns_packet *pkt;
431 tstamp next;
432 int retry;
433 struct dns_connection *dns;
434 int seqno;
435
436 dns_req (dns_connection *dns);
437 void gen_stream_req (int seqno, byte_stream &stream);
438};
439
440static u16 dns_id = 12098; // TODO: should be per-vpn 526static u16 dns_id = 0; // TODO: should be per-vpn
441 527
442static u16 next_id () 528static u16 next_id ()
443{ 529{
530 if (!dns_id)
531 dns_id = time (0);
532
444 // the simplest lsfr with periodicity 65535 i could find 533 // the simplest lsfr with periodicity 65535 i could find
445 dns_id = (dns_id << 1) 534 dns_id = (dns_id << 1)
446 | (((dns_id >> 1) 535 | (((dns_id >> 1)
447 ^ (dns_id >> 2) 536 ^ (dns_id >> 2)
448 ^ (dns_id >> 4) 537 ^ (dns_id >> 4)
449 ^ (dns_id >> 15)) & 1); 538 ^ (dns_id >> 15)) & 1);
450 539
451 return dns_id; 540 return dns_id;
452} 541}
453 542
543struct dns_rcv;
544struct dns_snd;
545
546struct dns_connection
547{
548 connection *c;
549 struct vpn *vpn;
550
551 dns_cfg cfg;
552
553 bool established;
554
555 tstamp last_received;
556 tstamp last_sent;
557 double min_latency;
558 double poll_interval, send_interval;
559
560 vector<dns_rcv *> rcvpq;
561
562 byte_stream rcvdq; int rcvseq; int repseq;
563 byte_stream snddq; int sndseq;
564
565 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
566 void receive_rep (dns_rcv *r);
567
568 dns_connection (connection *c);
569 ~dns_connection ();
570};
571
572struct dns_snd
573{
574 dns_packet *pkt;
575 tstamp timeout, sent;
576 int retry;
577 struct dns_connection *dns;
578 int seqno;
579 bool stdhdr;
580
581 void gen_stream_req (int seqno, byte_stream &stream);
582 void gen_syn_req ();
583
584 dns_snd (dns_connection *dns);
585 ~dns_snd ();
586};
587
454dns_req::dns_req (dns_connection *dns) 588dns_snd::dns_snd (dns_connection *dns)
455: dns (dns) 589: dns (dns)
456{ 590{
457 next = 0; 591 timeout = 0;
458 retry = 0; 592 retry = 0;
593 seqno = 0;
594 sent = ev_now ();
595 stdhdr = false;
459 596
460 pkt = new dns_packet; 597 pkt = new dns_packet;
461 598
462 pkt->id = next_id (); 599 pkt->id = next_id ();
463} 600}
464 601
602dns_snd::~dns_snd ()
603{
604 delete pkt;
605}
606
607static void append_domain (dns_packet &pkt, int &offs, const char *domain)
608{
609 // add tunnel domain
610 for (;;)
611 {
612 const char *end = strchr (domain, '.');
613
614 if (!end)
615 end = domain + strlen (domain);
616
617 int len = end - domain;
618
619 pkt [offs++] = len;
620 memcpy (pkt.at (offs), domain, len);
621 offs += len;
622
623 if (!*end)
624 break;
625
626 domain = end + 1;
627 }
628}
629
465void dns_req::gen_stream_req (int seqno, byte_stream &stream) 630void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
466{ 631{
632 stdhdr = true;
467 this->seqno = seqno; 633 this->seqno = seqno;
634
635 timeout = ev_now () + INITIAL_TIMEOUT;
468 636
469 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 637 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
470 pkt->qdcount = htons (1); 638 pkt->qdcount = htons (1);
471 639
472 int offs = 6*2; 640 int offs = 6*2;
473 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 641 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
474 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 642 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
475 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 643 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
476 644
477 char enc[256], *encp = enc; 645 char enc[256], *encp = enc;
478 encode_header (enc, THISNODE->id, seqno); 646 encode_header (enc, THISNODE->id, seqno);
496 encp += lbllen; 664 encp += lbllen;
497 665
498 enclen -= lbllen; 666 enclen -= lbllen;
499 } 667 }
500 668
501 const char *suffix = THISNODE->domain; 669 append_domain (*pkt, offs, dns->c->conf->domain);
502
503 // add tunnel domain
504 for (;;)
505 {
506 const char *end = strchr (suffix, '.');
507
508 if (!end)
509 end = suffix + strlen (suffix);
510
511 int len = end - suffix;
512
513 (*pkt)[offs++] = len;
514 memcpy (&((*pkt)[offs]), suffix, len);
515 offs += len;
516
517 if (!*end)
518 break;
519
520 suffix = end + 1;
521 }
522 670
523 (*pkt)[offs++] = 0; 671 (*pkt)[offs++] = 0;
524 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 672 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
673 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
674
675 pkt->len = offs;
676}
677
678void dns_snd::gen_syn_req ()
679{
680 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
681
682 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
683 pkt->qdcount = htons (1);
684
685 int offs = 6 * 2;
686
687 int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg));
688
689 assert (elen <= MAX_LBL_SIZE);
690
691 (*pkt)[offs] = elen;
692 offs += elen + 1;
693 append_domain (*pkt, offs, dns->c->conf->domain);
694
695 (*pkt)[offs++] = 0;
696 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
525 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 697 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
526 698
527 pkt->len = offs; 699 pkt->len = offs;
528} 700}
529 701
549 delete pkt; 721 delete pkt;
550} 722}
551 723
552///////////////////////////////////////////////////////////////////////////// 724/////////////////////////////////////////////////////////////////////////////
553 725
554struct dns_connection
555{
556 connection *c;
557 struct vpn *vpn;
558
559 vector<dns_rcv *> rcvpq;
560
561 int rcvseq;
562 int sndseq;
563
564 byte_stream rcvdq;
565 byte_stream snddq;
566
567 void time_cb (time_watcher &w); time_watcher tw;
568 void receive_rep (dns_rcv *r);
569
570 dns_connection (connection *c);
571 ~dns_connection ();
572};
573
574dns_connection::dns_connection (connection *c) 726dns_connection::dns_connection (connection *c)
575: c (c) 727: c (c)
576, rcvdq (MAX_BACKLOG * 2) 728, rcvdq (MAX_BACKLOG * 2)
577, snddq (MAX_BACKLOG * 2) 729, snddq (MAX_BACKLOG)
578, tw (this, &dns_connection::time_cb)
579{ 730{
731 tw.set<dns_connection, &dns_connection::time_cb> (this);
732
580 vpn = c->vpn; 733 vpn = c->vpn;
581 734
735 established = false;
736
582 rcvseq = sndseq = 0; 737 rcvseq = repseq = sndseq = 0;
738
739 last_sent = last_received = 0;
740 poll_interval = 0.5; // starting here
741 send_interval = 0.5; // starting rate
742 min_latency = INITIAL_TIMEOUT;
583} 743}
584 744
585dns_connection::~dns_connection () 745dns_connection::~dns_connection ()
586{ 746{
587 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 747 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
588 i != rcvpq.end (); 748 i != rcvpq.end ();
589 ++i) 749 ++i)
590 delete *i; 750 delete *i;
591} 751}
592 752
593struct dns_cfg
594{
595 u8 id1, id2, id3;
596 u8 def_ttl;
597 u8 unused1;
598 u16 max_size;
599 u8 flags1, flags2;
600};
601
602void dns_connection::receive_rep (dns_rcv *r) 753void dns_connection::receive_rep (dns_rcv *r)
603{ 754{
755 if (r->datalen)
756 {
757 last_received = ev_now ();
758 tw ();
759
760 poll_interval = send_interval;
761 }
762 else
763 {
764 poll_interval *= 1.5;
765
766 if (poll_interval > MAX_POLL_INTERVAL)
767 poll_interval = MAX_POLL_INTERVAL;
768 }
769
604 rcvpq.push_back (r); 770 rcvpq.push_back (r);
605 771
606 redo: 772 redo:
607 773
608 // find next packet 774 // find next packet
609 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 775 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
610 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 776 if (SEQNO_EQ (rcvseq, (*i)->seqno))
611 { 777 {
778 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
612 // enter the packet into our input stream 779 // enter the packet into our input stream
613 r = *i; 780 r = *i;
614 781
615 // remove the oldest packet, look forward, as it's oldest first 782 // remove the oldest packet, look forward, as it's oldest first
616 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 783 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
617 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 784 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
618 { 785 {
786 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
619 delete *j; 787 delete *j;
620 rcvpq.erase (j); 788 rcvpq.erase (j);
621 break; 789 break;
622 } 790 }
623 791
624 rcvseq = (rcvseq + 1) & SEQNO_MASK; 792 rcvseq = (rcvseq + 1) & SEQNO_MASK;
625 793
626 if (!rcvdq.put (r->data, r->datalen)) 794 if (!rcvdq.put (r->data, r->datalen))
795 {
796 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
627 abort (); // MUST never overflow, can be caused by data corruption, TODO 797 abort (); // MUST never overflow, can be caused by data corruption, TODO
798 }
628 799
629 while (vpn_packet *pkt = rcvdq.get ()) 800 while (vpn_packet *pkt = rcvdq.get ())
630 { 801 {
631 sockinfo si; 802 sockinfo si;
632 si.host = 0; si.port = 0; si.prot = PROT_DNSv4; 803 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
633 804
634 vpn->recv_vpn_packet (pkt, si); 805 vpn->recv_vpn_packet (pkt, si);
806
807 delete pkt;
635 } 808 }
636 809
637 // check for further packets 810 // check for further packets
638 goto redo; 811 goto redo;
639 } 812 }
640} 813}
641 814
642dns_packet * 815void
643vpn::dnsv4_server (dns_packet *pkt) 816vpn::dnsv4_server (dns_packet &pkt)
644{ 817{
645 u16 flags = ntohs (pkt->flags); 818 u16 flags = ntohs (pkt.flags);
646 819
647 //memcpy (&((*rep)[0]), &((*pkt)[0]), pkt->len);
648 int offs = 6 * 2; // skip header 820 int offs = 6 * 2; // skip header
649 821
650 pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 822 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
651 823
652 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK | FLAG_TC)) 824 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
653 && pkt->qdcount == htons (1)) 825 && pkt.qdcount == htons (1))
654 { 826 {
655 char qname[MAXSIZE]; 827 char qname [MAXSIZE];
656 int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs); 828 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
657 829
658 u16 qtype = (*pkt) [offs++] << 8; qtype |= (*pkt) [offs++]; 830 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
659 u16 qclass = (*pkt) [offs++] << 8; qclass |= (*pkt) [offs++]; 831 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
660 832
661 pkt->qdcount = htons (1); 833 pkt.qdcount = htons (1);
662 pkt->ancount = 0; 834 pkt.ancount = 0;
663 pkt->nscount = 0; // should be self, as other nameservers reply like this 835 pkt.nscount = 0; // should be self, as other nameservers reply like this
664 pkt->arcount = 0; // a record for self, as other nameservers reply like this 836 pkt.arcount = 0; // a record for self, as other nameservers reply like this
665 837
666 pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_NXDOMAIN); 838 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_SERVFAIL);
667 839
668 int dlen = strlen (THISNODE->domain); 840 int dlen = strlen (THISNODE->domain);
669 841
670 if (qclass == RR_CLASS_IN 842 if (qclass == RR_CLASS_IN
671 && (qtype == RR_TYPE_ANY || qtype == RR_TYPE_TXT)
672 && qlen > dlen + 1 + HDRSIZE 843 && qlen > dlen + 1
673 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 844 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
674 { 845 {
675 // correct class, domain: parse 846 // now generate reply
676 int client, seqno; 847 pkt.ancount = htons (1); // one answer RR
677 decode_header (qname, client, seqno); 848 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
678 849
679 u8 data[MAXSIZE]; 850 if ((qtype == RR_TYPE_ANY
680 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE)); 851 || qtype == RR_TYPE_TXT
681 852 || qtype == RR_TYPE_NULL)
682 if (0 < client && client <= conns.size ()) 853 && qlen > dlen + 1 + HDRSIZE)
683 { 854 {
855 // correct class, domain: parse
856 int client, seqno;
857 decode_header (qname, client, seqno);
858
859 u8 data[MAXSIZE];
860 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
861
862 if (0 < client && client <= conns.size ())
863 {
684 connection *c = conns [client - 1]; 864 connection *c = conns [client - 1];
685
686 if (!c->dns)
687 c->dns = new dns_connection (c);
688
689 dns_connection *dns = c->dns; 865 dns_connection *dns = c->dns;
866 dns_rcv *rcv;
690 867
868 if (dns)
869 {
691 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 870 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
692 if (SEQNO_EQ ((*i)->seqno, seqno)) 871 if (SEQNO_EQ ((*i)->seqno, seqno))
872 {
873 // already seen that request: simply reply with the cached reply
874 dns_rcv *r = *i;
875
876 slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
877
878 // refresh header & id, as the retry count could have changed
879 memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
880 r->pkt->id = pkt.id;
881
882 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
883
884 goto duplicate_request;
885 }
886
887 // new packet, queue
888 rcv = new dns_rcv (seqno, data, datalen);
889 dns->receive_rep (rcv);
890 }
891
693 { 892 {
694 // already seen that request: simply reply with the cached reply 893 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
695 dns_rcv *r = *i;
696 894
697 printf ("DUPLICATE %d\n", htons (r->pkt->id));//D 895 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
896 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
897 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
898 pkt [offs++] = 0; pkt [offs++] = 0;
899 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
698 900
699 memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len); 901 int rdlen_offs = offs += 2;
700 pkt->id = r->pkt->id; 902
701 goto duplicate_request; 903 if (dns)
904 {
905 int dlen = ntohs (dns->cfg.max_size) - offs;
906
907 // bind doesn't compress well, so reduce further by one label length
908 dlen -= qlen;
909
910 // only put data into in-order sequence packets, if
911 // we receive out-of-order packets we generate empty
912 // replies
913 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
914 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
915 {
916 dns->repseq = seqno;
917
918 while (dlen > 1 && !dns->snddq.empty ())
919 {
920 int txtlen = dlen <= 255 ? dlen - 1 : 255;
921
922 if (txtlen > dns->snddq.size ())
923 txtlen = dns->snddq.size ();
924
925 pkt[offs++] = txtlen;
926 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
927 offs += txtlen;
928 dns->snddq.remove (txtlen);
929
930 dlen -= txtlen + 1;
931 }
932 }
933
934 // avoid completely empty TXT rdata
935 if (offs == rdlen_offs)
936 pkt[offs++] = 0;
937
938 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
939 }
940 else
941 {
942 // send RST
943 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
944 pkt [offs++] = CMD_IP_RST;
945 }
946
947 int rdlen = offs - rdlen_offs;
948
949 pkt [rdlen_offs - 2] = rdlen >> 8;
950 pkt [rdlen_offs - 1] = rdlen;
951
952 if (dns)
953 {
954 // now update dns_rcv copy
955 rcv->pkt->len = offs;
956 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
957 }
702 } 958 }
703 959
704 // new packet, queue 960 duplicate_request: ;
705 dns_rcv *rcv = new dns_rcv (seqno, data, datalen); 961 }
706 dns->receive_rep (rcv); 962 else
707
708 // now generate reply
709 pkt->ancount = htons (1); // one answer RR
710 pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 963 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
964 }
965 else if (qtype == RR_TYPE_A
966 && qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
967 {
968 dns_cfg cfg;
969 cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
970 int client = ntohs (cfg.client);
711 971
712 (*pkt) [offs++] = 0xc0;
713 (*pkt) [offs++] = 6 * 2; // same as in query section 972 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
714 973
715 (*pkt) [offs++] = RR_TYPE_TXT >> 8; (*pkt) [offs++] = RR_TYPE_TXT; 974 pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
716 (*pkt) [offs++] = RR_CLASS_IN >> 8; (*pkt) [offs++] = RR_CLASS_IN; 975 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
717
718 (*pkt) [offs++] = 0; (*pkt) [offs++] = 0; 976 pkt [offs++] = 0; pkt [offs++] = 0;
719 (*pkt) [offs++] = 0; (*pkt) [offs++] = 0; // TTL 977 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
978 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
720 979
721 int dlen = MAX_PKT_SIZE - offs - 2; 980 slog (L_INFO, _("DNS: client %d connects"), client);
722 981
723 // bind doesn't compress well, so reduce further by one label length 982 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
724 dlen -= qlen; 983 pkt [offs++] = CMD_IP_REJ;
725 984
726 int rdlen_offs = offs += 2; 985 if (0 < client && client <= conns.size ())
727
728 while (dlen > 1 && !dns->snddq.empty ())
729 { 986 {
730 int txtlen = dlen <= 255 ? dlen - 1 : 255; 987 connection *c = conns [client - 1];
731 988
732 if (txtlen > dns->snddq.size ()) 989 if (cfg.valid ())
733 txtlen = dns->snddq.size (); 990 {
991 pkt [offs - 1] = CMD_IP_SYN;
734 992
735 (*pkt)[offs++] = txtlen; 993 delete c->dns;
736 memcpy (pkt->at (offs), dns->snddq.begin (), txtlen); 994 c->dns = new dns_connection (c);
737 offs += txtlen; 995 c->dns->cfg = cfg;
738 dns->snddq.remove (txtlen); 996 }
739
740 dlen -= txtlen + 1;
741 } 997 }
742
743 // avoid empty TXT rdata
744 if (offs == rdlen_offs)
745 (*pkt)[offs++] = 0;
746
747 int rdlen = offs - rdlen_offs;
748
749 (*pkt) [rdlen_offs - 2] = rdlen >> 8;
750 (*pkt) [rdlen_offs - 1] = rdlen;
751
752 // now update dns_rcv copy
753 rcv->pkt->len = offs;
754 memcpy (rcv->pkt->at (0), pkt->at (0), offs);
755
756 duplicate_request: ;
757 } 998 }
758 else
759 pkt->flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
760 } 999 }
761 1000
762 pkt->len = offs; 1001 pkt.len = offs;
763 } 1002 }
764
765 return pkt;
766} 1003}
767 1004
768void 1005void
769vpn::dnsv4_client (dns_packet *pkt) 1006vpn::dnsv4_client (dns_packet &pkt)
770{ 1007{
771 u16 flags = ntohs (pkt->flags); 1008 u16 flags = ntohs (pkt.flags);
772 int offs = 6 * 2; // skip header 1009 int offs = 6 * 2; // skip header
773 1010
774 pkt->qdcount = ntohs (pkt->qdcount); 1011 pkt.qdcount = ntohs (pkt.qdcount);
775 pkt->ancount = ntohs (pkt->ancount); 1012 pkt.ancount = ntohs (pkt.ancount);
776 1013
777 // go through our request list and find the corresponding request 1014 // go through our request list and find the corresponding request
778 for (vector<dns_req *>::iterator i = dns_sndpq.begin (); 1015 for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
779 i != dns_sndpq.end (); 1016 i != dns_sndpq.end ();
780 ++i) 1017 ++i)
781 if ((*i)->pkt->id == pkt->id) 1018 if ((*i)->pkt->id == pkt.id)
782 { 1019 {
783 dns_connection *dns = (*i)->dns; 1020 dns_connection *dns = (*i)->dns;
1021 connection *c = dns->c;
784 int seqno = (*i)->seqno; 1022 int seqno = (*i)->seqno;
785 u8 data[MAXSIZE], *datap = data; 1023 u8 data[MAXSIZE], *datap = data;
1024 //printf ("rcv pkt %x\n", seqno);//D
1025
1026 if ((*i)->retry)
1027 {
1028 dns->send_interval *= 1.01;
1029 if (dns->send_interval > MAX_SEND_INTERVAL)
1030 dns->send_interval = MAX_SEND_INTERVAL;
1031 }
1032 else
1033 {
1034#if 0
1035 dns->send_interval *= 0.999;
1036#endif
1037 // the latency surely puts an upper bound on
1038 // the minimum send interval
1039 double latency = ev_now () - (*i)->sent;
1040
1041 if (latency < dns->min_latency)
1042 dns->min_latency = latency;
1043
1044 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1045 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1046
1047 if (dns->send_interval < conf.dns_send_interval)
1048 dns->send_interval = conf.dns_send_interval;
1049 }
786 1050
787 delete *i; 1051 delete *i;
788 dns_sndpq.erase (i); 1052 dns_sndpq.erase (i);
789 1053
790 if (flags & FLAG_RESPONSE && !(flags & (FLAG_OP_MASK | FLAG_TC))) 1054 if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
791 { 1055 {
792 char qname[MAXSIZE]; 1056 char qname[MAXSIZE];
793 1057
794 while (pkt->qdcount-- && offs < MAXSIZE - 4) 1058 while (pkt.qdcount-- && offs < MAXSIZE - 4)
795 { 1059 {
796 int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs); 1060 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
797 offs += 4; // skip qtype, qclass 1061 offs += 4; // skip qtype, qclass
798 } 1062 }
799 1063
800 while (pkt->ancount-- && offs < MAXSIZE - 10 && datap) 1064 while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
801 { 1065 {
802 int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs); 1066 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
803 1067
804 u16 qtype = (*pkt) [offs++] << 8; qtype |= (*pkt) [offs++]; 1068 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
805 u16 qclass = (*pkt) [offs++] << 8; qclass |= (*pkt) [offs++]; 1069 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
806 u32 ttl = (*pkt) [offs++] << 24; 1070 u32 ttl = pkt [offs++] << 24;
807 ttl |= (*pkt) [offs++] << 16; 1071 ttl |= pkt [offs++] << 16;
808 ttl |= (*pkt) [offs++] << 8; 1072 ttl |= pkt [offs++] << 8;
809 ttl |= (*pkt) [offs++]; 1073 ttl |= pkt [offs++];
810
811 u16 rdlen = (*pkt) [offs++] << 8; rdlen |= (*pkt) [offs++]; 1074 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
812 1075
813 if (rdlen <= MAXSIZE - offs) 1076 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT)
814 { 1077 {
815 // decode bytes, finally 1078 if (rdlen <= MAXSIZE - offs)
816
817 while (rdlen)
818 { 1079 {
1080 // decode bytes, finally
1081
1082 while (rdlen)
1083 {
819 int txtlen = (*pkt) [offs++]; 1084 int txtlen = pkt [offs++];
820 1085
821 assert (txtlen + offs < MAXSIZE - 1); 1086 assert (txtlen + offs < MAXSIZE - 1);
822 1087
823 memcpy (datap, pkt->at (offs), txtlen); 1088 memcpy (datap, pkt.at (offs), txtlen);
824 datap += txtlen; offs += txtlen; 1089 datap += txtlen; offs += txtlen;
825 1090
826 rdlen -= txtlen + 1; 1091 rdlen -= txtlen + 1;
1092 }
827 } 1093 }
828 } 1094 }
1095 else if (qtype == RR_TYPE_A)
1096 {
1097 u8 ip [4];
1098
1099 ip [0] = pkt [offs++];
1100 ip [1] = pkt [offs++];
1101 ip [2] = pkt [offs++];
1102 ip [3] = pkt [offs++];
1103
1104 if (ip [0] == CMD_IP_1
1105 && ip [1] == CMD_IP_2
1106 && ip [2] == CMD_IP_3)
1107 {
1108 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1109
1110 if (ip [3] == CMD_IP_RST)
1111 {
1112 slog (L_DEBUG, _("DNS: got tunnel RST request"));
1113
1114 delete dns; c->dns = 0;
1115
1116 return;
1117 }
1118 else if (ip [3] == CMD_IP_SYN)
1119 {
1120 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1121 dns->established = true;
1122 }
1123 else if (ip [3] == CMD_IP_REJ)
1124 {
1125 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
1126 abort ();
1127 }
1128 else
1129 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1130 }
1131 else
1132 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1133 ip [0], ip [1], ip [2], ip [3]);
1134
1135 return;
1136 }
829 1137
830 int client, rseqno; 1138 int client, rseqno;
831 decode_header (qname, client, rseqno); 1139 decode_header (qname, client, rseqno);
832 1140
833 if (client != THISNODE->id) 1141 if (client != THISNODE->id)
834 { 1142 {
835 slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring")); 1143 slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
836 datap = 0; 1144 datap = 0;
837 } 1145 }
838 else if (rseqno != seqno) 1146 else if (rseqno != seqno)
839 { 1147 {
840 slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?")); 1148 slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
841 datap = 0; 1149 datap = 0;
842 } 1150 }
843 } 1151 }
844 } 1152 }
845 1153
847 if (datap) 1155 if (datap)
848 dns->receive_rep (new dns_rcv (seqno, data, datap - data)); 1156 dns->receive_rep (new dns_rcv (seqno, data, datap - data));
849 1157
850 break; 1158 break;
851 } 1159 }
852
853 delete pkt;
854} 1160}
855 1161
856void 1162void
857vpn::dnsv4_ev (io_watcher &w, short revents) 1163vpn::dnsv4_ev (ev::io &w, int revents)
858{ 1164{
859 if (revents & EVENT_READ) 1165 if (revents & EV_READ)
860 { 1166 {
861 dns_packet *pkt = new dns_packet; 1167 dns_packet *pkt = new dns_packet;
862 struct sockaddr_in sa; 1168 struct sockaddr_in sa;
863 socklen_t sa_len = sizeof (sa); 1169 socklen_t sa_len = sizeof (sa);
864 1170
865 pkt->len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1171 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
866 1172
867 if (pkt->len > 0) 1173 if (pkt->len > 0)
868 { 1174 {
869 if (pkt->flags & htons (FLAG_TC)) 1175 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1176 dnsv4_client (*pkt);
1177 else
870 { 1178 {
871 slog (L_WARN, _("DNS request/response truncated, check protocol settings.")); 1179 dnsv4_server (*pkt);
872 //TODO connection reset 1180 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
873 } 1181 }
874 1182
875 if (THISNODE->dns_port) 1183 delete pkt;
876 {
877 pkt = dnsv4_server (pkt);
878 sendto (w.fd, &((*pkt)[0]), pkt->len, 0, (sockaddr *)&sa, sa_len);
879 }
880 else
881 dnsv4_client (pkt);
882 } 1184 }
883 } 1185 }
884} 1186}
885 1187
886bool 1188bool
887connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1189vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
888{ 1190{
1191 int client = ntohl (si.host);
1192
1193 assert (0 < client && client <= conns.size ());
1194
1195 connection *c = conns [client - 1];
1196
889 if (!dns) 1197 if (!c->dns)
890 dns = new dns_connection (this); 1198 c->dns = new dns_connection (c);
891 1199
892 if (!dns->snddq.put (pkt)) 1200 if (c->dns->snddq.put (pkt))
893 return false; 1201 c->dns->tw ();
894 1202
895 // start timer if neccessary 1203 // always return true even if the buffer overflows
896 if (!THISNODE->dns_port && !dns->tw.active)
897 dns->tw.trigger ();
898
899 return true; 1204 return true;
900} 1205}
901 1206
902void 1207void
903dns_connection::time_cb (time_watcher &w) 1208connection::dnsv4_reset_connection ()
904{ 1209{
1210 //delete dns; dns = 0; //TODO
1211}
1212
1213#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1214
1215void
1216dns_connection::time_cb (ev::timer &w, int revents)
1217{
1218 // servers have to be polled
1219 if (THISNODE->dns_port)
1220 return;
1221
905 // check for timeouts and (re)transmit 1222 // check for timeouts and (re)transmit
906 tstamp next = NOW + 60; 1223 tstamp next = ev::now () + poll_interval;
907 dns_req *send = 0; 1224 dns_snd *send = 0;
908 1225
909 for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin (); 1226 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
910 i != vpn->dns_sndpq.end (); 1227 i != vpn->dns_sndpq.end ();
911 ++i) 1228 ++i)
912 { 1229 {
913 dns_req *r = *i; 1230 dns_snd *r = *i;
914 1231
915 if (r->next <= NOW) 1232 if (r->timeout <= ev_now ())
916 { 1233 {
917 if (!send) 1234 if (!send)
918 { 1235 {
919 send = r; 1236 send = r;
920 1237
921 if (r->retry)//D
922 printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
923 r->retry++; 1238 r->retry++;
924 r->next = NOW + r->retry; 1239 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1240 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1241
1242 // the following code changes the query section a bit, forcing
1243 // the forwarder to generate a new request
1244 if (r->stdhdr)
1245 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
925 } 1246 }
926 } 1247 }
927 1248 else
928 if (r->next < next) 1249 NEXT (r->timeout);
929 next = r->next;
930 } 1250 }
931 1251
932 if (!send 1252 if (!send)
933 && vpn->dns_sndpq.size () < MAX_OUTSTANDING)
934 { 1253 {
1254 // generate a new packet, if wise
1255
1256 if (!established)
1257 {
1258 if (vpn->dns_sndpq.empty ())
1259 {
935 send = new dns_req (this); 1260 send = new dns_snd (this);
1261
1262 cfg.reset (THISNODE->id);
1263 send->gen_syn_req ();
1264 }
1265 }
1266 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1267 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1268 {
1269 if (last_sent + send_interval <= ev_now ())
1270 {
1271 //printf ("sending data request etc.\n"); //D
1272 if (!snddq.empty () || last_received + 1. > ev_now ())
1273 {
1274 poll_interval = send_interval;
1275 NEXT (ev_now () + send_interval);
1276 }
1277
1278 send = new dns_snd (this);
936 send->gen_stream_req (sndseq, snddq); 1279 send->gen_stream_req (sndseq, snddq);
1280 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1281 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1282
1283 sndseq = (sndseq + 1) & SEQNO_MASK;
1284 }
1285 else
1286 NEXT (last_sent + send_interval);
1287 }
1288
1289 if (send)
937 vpn->dns_sndpq.push_back (send); 1290 vpn->dns_sndpq.push_back (send);
938
939 sndseq = (sndseq + 1) & SEQNO_MASK;
940 } 1291 }
941
942 tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
943 1292
944 if (send) 1293 if (send)
945 { 1294 {
946 dns_packet *pkt = send->pkt; 1295 last_sent = ev_now ();
947 1296 sendto (vpn->dnsv4_fd,
948 next = min_next; 1297 send->pkt->at (0), send->pkt->len, 0,
949
950 sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0,
951 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1298 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
952 } 1299 }
953 else if (next < min_next)
954 next = min_next;
955 1300
956 w.start (next); 1301 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1302 poll_interval, send_interval, next - ev_now (),
1303 vpn->dns_sndpq.size (), snddq.size (),
1304 rcvpq.size ());
1305
1306 // TODO: no idea when this happens, but when next < ev_now (), we have a problem
1307 // doesn't seem to happen anymore
1308 if (next < ev_now () + 0.001)
1309 next = ev_now () + 0.1;
1310
1311 w.start (next - ev_now ());
957} 1312}
958 1313
959#endif 1314#endif
960 1315

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