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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.49 by root, Tue Feb 8 23:11:36 2011 UTC vs.
Revision 1.53 by root, Tue Oct 18 10:54:17 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) 2003-2008 Marc Lehmann <gvpe@schmorp.de> 3 Copyright (C) 2003-2011 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 it 7 GVPE is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the 8 under the terms of the GNU General Public License as published by the
… …
59 59
60#include "netcompat.h" 60#include "netcompat.h"
61 61
62#include "vpn.h" 62#include "vpn.h"
63 63
64#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received
64#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data 65#define MAX_POLL_INTERVAL 1. // how often to poll minimally when the server has no data
65#define ACTIVITY_INTERVAL 5.
66 66
67#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
69 69
70#define MAX_SEND_INTERVAL 2. // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
71 71
72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
73#define MAX_BACKLOG (64*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
74 74
75#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well 75#define MAX_DOMAIN_SIZE 235 // 255 is legal limit, but bind doesn't compress well
76// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
77// every request byte less give room for two reply bytes 77// every request byte less give room for two reply bytes
78 78
79#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
… …
91#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
92 92
93#define CMD_IP_1 207 93#define CMD_IP_1 207
94#define CMD_IP_2 46 94#define CMD_IP_2 46
95#define CMD_IP_3 236 95#define CMD_IP_3 236
96#define CMD_IP_RST 29 96
97#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
98#define CMD_IP_REJ 32 98#define CMD_IP_REJ 32 // do not want you
99#define CMD_IP_SYN 113 // connection established
100#define CMD_IP_CSE 213 // connection established, but likely case mismatch
101
102static bool
103is_uc (char c)
104{
105 return 'A' <= c && c <= 'Z';
106}
107
108static bool
109is_lc (char c)
110{
111 return 'a' <= c && c <= 'z';
112}
99 113
100// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
101struct charmap 115struct charmap
102{ 116{
103 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
… …
117 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
118 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
119 133
120 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
121 { 135 {
136 char c = cmap [size];
137
122 enc [size] = cmap [size]; 138 enc [size] = c;
123 dec [(u8)enc [size]] = size; 139 dec [(u8)c] = size;
140
141 // allow lowercase/uppercase aliases if possible
142 if (is_uc (c) && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size;
143 if (is_lc (c) && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size;
124 } 144 }
125 145
126 assert (size < 256); 146 assert (size < 256);
127} 147}
128 148
… …
135{ 155{
136 charmap cmap; 156 charmap cmap;
137 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
138 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
139 159
140 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
141 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
142 162
143 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
144 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
145 165
146 basecoder (const char *cmap); 166 basecoder (const char *cmap);
147}; 167};
148 168
149basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
169 dec_len [n] = len; 189 dec_len [n] = len;
170 } 190 }
171} 191}
172 192
173unsigned int 193unsigned int
174basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
175{ 195{
176 return enc_len [len]; 196 return enc_len [len];
177} 197}
178 198
179unsigned int 199unsigned int
180basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
181{ 201{
182 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
183 --len; 203 --len;
184 204
185 return dec_len [len]; 205 return dec_len [len];
186} 206}
187 207
188unsigned int 208unsigned int
189basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
190{ 210{
191 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
192 return 0; 212 return 0;
193 213
194 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
214 234
215 return elen; 235 return elen;
216} 236}
217 237
218unsigned int 238unsigned int
219basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
220{ 240{
221 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
222 return 0; 242 return 0;
223 243
224 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
273 } 293 }
274 abort (); 294 abort ();
275} 295}
276#endif 296#endif
277 297
278//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
279//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
280static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
281//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
282static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
283 301
284///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
285 303
286#define HDRSIZE 6 304#define HDRSIZE 5
287 305
288inline void 306inline void
289encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
290{ 308{
309 assert (clientid < 256);
310
291 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
292 312
293 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
294 clientid, 316 clientid,
295 (seqno >> 8) | (retry << 6),
296 seqno,
297 }; 317 };
298 318
299 assert (clientid < 256);
300
301 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
302} 320}
303 321
304inline void 322inline void
305decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
306{ 324{
307 u8 hdr[3]; 325 u8 hdr[3];
308 326
309 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
310 328
311 clientid = hdr[0]; 329 clientid = hdr[2];
312 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
313} 331}
314 332
315///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
316 334
317struct byte_stream 335struct byte_stream
… …
430 448
431struct dns_cfg 449struct dns_cfg
432{ 450{
433 static int next_uid; 451 static int next_uid;
434 452
435 u8 id1, id2, id3, id4; 453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
436 456
437 u8 version; 457 u8 version;
438 u8 flags; 458 u8 flags;
439 u8 rrtype; 459 u16 max_size;
460
461 u8 id1, id2, id3, id4;
462
463 u16 client;
440 u8 def_ttl; 464 u8 def_ttl;
465 u8 r0;
441 466
442 u16 client; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
443 u16 uid; // to make request unique 468 u8 hdr_cdc; // cdc en/decoder for regular request headers
469 u8 req_cdc; // cdc en/decoder for regular (ANY?) request data
470 u8 rep_cdc; // cdc en/decoder for regular (TXT) replies, 0 == 8 bit encoding
444 471
445 u16 max_size;
446 u8 seq_cdc;
447 u8 req_cdc;
448
449 u8 rep_cdc;
450 u8 delay; // time in 0.01s units that the server may delay replying packets
451 u8 r3, r4;
452
453 u8 r5, r6, r7, r8; 472 u8 r1, r2, r3, r4;
454 473
455 void reset (int clientid); 474 void reset (int clientid);
456 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
457}; 477};
458 478
459int dns_cfg::next_uid; 479int dns_cfg::next_uid;
460 480
461void 481void
462dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
463{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
464 id1 = 'G'; 485 id1 = 'G';
465 id2 = 'V'; 486 id2 = 'V';
466 id3 = 'P'; 487 id3 = 'P';
467 id4 = 'E'; 488 id4 = 'E';
468 489
469 version = 1; 490 version = 2;
470 491
471 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
472 flags = 0; 493 flags = 0;
473 def_ttl = 0; 494 def_ttl = 0;
474 seq_cdc = 26; 495 syn_cdc = 26;
475 req_cdc = 62; 496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
476 rep_cdc = 0; 498 rep_cdc = 0;
477 max_size = htons (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
478 client = htons (clientid); 500 client = htons (clientid);
479 uid = next_uid++; 501 uid = ++next_uid;
480 delay = 0;
481 502
482 r3 = r4 = 0; 503 r0 = r1 = r2 = r3 = r4 = 0;
483 r4 = r5 = r6 = r7 = 0; 504
505 chksum = get_chksum ();
506}
507
508// simple but not trivial chksum
509u8
510dns_cfg::get_chksum ()
511{
512 unsigned int sum = 0xff00; // only 16 bits required
513
514 u8 old_chksum = chksum;
515 chksum = 0;
516
517 for (unsigned int i = 0; i < sizeof (*this); ++i)
518 sum += ((u8 *)this)[i] * (i + 1);
519
520 chksum = old_chksum;
521
522 return sum + (sum >> 8);
484} 523}
485 524
486bool 525bool
487dns_cfg::valid () 526dns_cfg::valid ()
488{ 527{
… …
490 // only the following encoding/decoding settings are implemented. 529 // only the following encoding/decoding settings are implemented.
491 return id1 == 'G' 530 return id1 == 'G'
492 && id2 == 'V' 531 && id2 == 'V'
493 && id3 == 'P' 532 && id3 == 'P'
494 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
495 && seq_cdc == 26 535 && syn_cdc == 26
496 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
497 && rep_cdc == 0 538 && rep_cdc == 0
498 && version == 1; 539 && chksum == get_chksum ();
499} 540}
500 541
501struct dns_packet : net_packet 542struct dns_packet : net_packet
502{ 543{
503 u16 id; 544 u16 id;
… …
549static 590static
550u16 next_id () 591u16 next_id ()
551{ 592{
552 static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
553 594
595#if 1
554 if (!dns_id) 596 if (!dns_id)
555 dns_id = time (0); 597 dns_id = time (0);
556 598
557 // the simplest lsfr with periodicity 65535 i could find 599 // the simplest lsfr with periodicity 65535 i could find
558 dns_id = (dns_id << 1) 600 dns_id = (dns_id << 1)
… …
560 ^ (dns_id >> 2) 602 ^ (dns_id >> 2)
561 ^ (dns_id >> 4) 603 ^ (dns_id >> 4)
562 ^ (dns_id >> 15)) & 1); 604 ^ (dns_id >> 15)) & 1);
563 605
564 return dns_id; 606 return dns_id;
607#else
608 dns_id++;//D
609
610 return htons (dns_id);
611#endif
565} 612}
566 613
567struct dns_rcv; 614struct dns_rcv;
568struct dns_snd; 615struct dns_snd;
569 616
… …
573 struct vpn *vpn; 620 struct vpn *vpn;
574 621
575 dns_cfg cfg; 622 dns_cfg cfg;
576 623
577 bool established; 624 bool established;
625 const basecoder *cdc;
578 626
579 tstamp last_received; 627 tstamp last_received;
580 tstamp last_sent; 628 tstamp last_sent;
581 double min_latency; 629 double min_latency;
582 double poll_interval, send_interval; 630 double poll_interval, send_interval;
… …
586 byte_stream rcvdq; int rcvseq; int repseq; 634 byte_stream rcvdq; int rcvseq; int repseq;
587 byte_stream snddq; int sndseq; 635 byte_stream snddq; int sndseq;
588 636
589 inline void time_cb (ev::timer &w, int revents); ev::timer tw; 637 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
590 void receive_rep (dns_rcv *r); 638 void receive_rep (dns_rcv *r);
639
640 void reset (); // quite like tcp RST
641 void set_cfg (); // to be called after any cfg changes
591 642
592 dns_connection (connection *c); 643 dns_connection (connection *c);
593 ~dns_connection (); 644 ~dns_connection ();
594}; 645};
595 646
… …
669 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 720 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
670 721
671 char enc[256], *encp = enc; 722 char enc[256], *encp = enc;
672 encode_header (enc, THISNODE->id, seqno); 723 encode_header (enc, THISNODE->id, seqno);
673 724
674 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 725 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
675 726
676 if (datalen > stream.size ()) 727 if (datalen > stream.size ())
677 datalen = stream.size (); 728 datalen = stream.size ();
678 729
679 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 730 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
680 stream.remove (datalen); 731 stream.remove (datalen);
681 732
682 while (enclen) 733 while (enclen)
683 { 734 {
684 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 735 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
757{ 808{
758 tw.set<dns_connection, &dns_connection::time_cb> (this); 809 tw.set<dns_connection, &dns_connection::time_cb> (this);
759 810
760 vpn = c->vpn; 811 vpn = c->vpn;
761 812
813 reset ();
814}
815
816dns_connection::~dns_connection ()
817{
818 reset ();
819}
820
821void
822dns_connection::reset ()
823{
824 while (!rcvpq.empty ())
825 {
826 delete rcvpq.back ();
827 rcvpq.pop_back ();
828 }
829
830 for (int i = vpn->dns_sndpq.size (); i--; )
831 if (vpn->dns_sndpq [i]->dns == this)
832 {
833 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
834 vpn->dns_sndpq.pop_back ();
835 }
836
762 established = false; 837 established = false;
763 838
764 rcvseq = repseq = sndseq = 0; 839 rcvseq = repseq = sndseq = 0;
765 840
766 last_sent = last_received = 0; 841 last_sent = 0;
767 poll_interval = 0.5; // starting here 842 poll_interval = 0.5; // starting here
768 send_interval = 0.5; // starting rate 843 send_interval = 0.5; // starting rate
769 min_latency = INITIAL_TIMEOUT; 844 min_latency = INITIAL_TIMEOUT;
770} 845}
771 846
772dns_connection::~dns_connection () 847void
848dns_connection::set_cfg ()
773{ 849{
774 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 850 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
775 i != rcvpq.end ();
776 ++i)
777 delete *i;
778} 851}
779 852
780void 853void
781dns_connection::receive_rep (dns_rcv *r) 854dns_connection::receive_rep (dns_rcv *r)
782{ 855{
783 if (r->datalen) 856 if (r->datalen)
784 { 857 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
785 last_received = ev_now ();
786 tw ();
787
788 poll_interval = send_interval;
789 }
790 else 858 else
791 { 859 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
792 poll_interval *= 1.5;
793
794 if (poll_interval > MAX_POLL_INTERVAL)
795 poll_interval = MAX_POLL_INTERVAL;
796 }
797 860
798 rcvpq.push_back (r); 861 rcvpq.push_back (r);
799 862
800 redo: 863 redo:
801 864
… …
819 882
820 rcvseq = (rcvseq + 1) & SEQNO_MASK; 883 rcvseq = (rcvseq + 1) & SEQNO_MASK;
821 884
822 if (!rcvdq.put (r->data, r->datalen)) 885 if (!rcvdq.put (r->data, r->datalen))
823 { 886 {
887 // MUST never overflow, can be caused by data corruption, TODO
824 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 888 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
825 abort (); // MUST never overflow, can be caused by data corruption, TODO 889 reset ();
890 return;
826 } 891 }
827 892
828 while (vpn_packet *pkt = rcvdq.get ()) 893 while (vpn_packet *pkt = rcvdq.get ())
829 { 894 {
830 sockinfo si; 895 sockinfo si;
831 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; 896 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
832 897
833 vpn->recv_vpn_packet (pkt, si); 898 vpn->recv_vpn_packet (pkt, si);
834
835 delete pkt; 899 delete pkt;
836 } 900 }
837 901
838 // check for further packets 902 // check for further packets
839 goto redo; 903 goto redo;
… …
882 { 946 {
883 // correct class, domain: parse 947 // correct class, domain: parse
884 int client, seqno; 948 int client, seqno;
885 decode_header (qname, client, seqno); 949 decode_header (qname, client, seqno);
886 950
887 u8 data[MAXSIZE];
888 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
889
890 if (0 < client && client <= conns.size ()) 951 if (0 < client && client <= conns.size ())
891 { 952 {
892 connection *c = conns [client - 1]; 953 connection *c = conns [client - 1];
893 dns_connection *dns = c->dns; 954 dns_connection *dns = c->dns;
894 dns_rcv *rcv; 955 dns_rcv *rcv;
895 956
896 if (dns) 957 if (dns)
897 { 958 {
959 u8 data[MAXSIZE];
960 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
961
898 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 962 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
899 if (SEQNO_EQ ((*i)->seqno, seqno)) 963 if (SEQNO_EQ ((*i)->seqno, seqno))
900 { 964 {
901 // already seen that request: simply reply with the cached reply 965 // already seen that request: simply reply with the cached reply
902 dns_rcv *r = *i; 966 dns_rcv *r = *i;
… …
1003 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1067 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
1004 pkt [offs++] = 0; pkt [offs++] = 0; 1068 pkt [offs++] = 0; pkt [offs++] = 0;
1005 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1069 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
1006 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1070 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
1007 1071
1008 slog (L_INFO, _("DNS: client %d connects"), client);
1009
1010 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1072 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
1011 pkt [offs++] = CMD_IP_REJ; 1073 pkt [offs++] = CMD_IP_REJ;
1012 1074
1013 if (0 < client && client <= conns.size ()) 1075 if (0 < client && client <= conns.size ())
1014 { 1076 {
1015 connection *c = conns [client - 1]; 1077 connection *c = conns [client - 1];
1016 1078
1017 if (cfg.valid ()) 1079 if (cfg.valid ())
1018 { 1080 {
1019 pkt [offs - 1] = CMD_IP_SYN; 1081 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1082
1083 // check for any encoding mismatches - hints at a case problem
1084 char qname2 [MAX_ENC_LEN];
1085 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
1020 1086
1021 delete c->dns; 1087 delete c->dns;
1088
1089 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1090 ? CMD_IP_CSE : CMD_IP_SYN;
1091
1022 c->dns = new dns_connection (c); 1092 c->dns = new dns_connection (c);
1023 c->dns->cfg = cfg; 1093 c->dns->cfg = cfg;
1094 c->dns->set_cfg ();
1024 } 1095 }
1025 } 1096 }
1026 } 1097 }
1027 } 1098 }
1028 1099
… …
1099 ttl |= pkt [offs++] << 16; 1170 ttl |= pkt [offs++] << 16;
1100 ttl |= pkt [offs++] << 8; 1171 ttl |= pkt [offs++] << 8;
1101 ttl |= pkt [offs++]; 1172 ttl |= pkt [offs++];
1102 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1173 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1103 1174
1104 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1175 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1105 { 1176 {
1106 if (rdlen <= MAXSIZE - offs) 1177 if (rdlen <= MAXSIZE - offs)
1107 { 1178 {
1108 // decode bytes, finally 1179 // decode bytes, finally
1109 1180
… …
1135 { 1206 {
1136 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1207 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1137 1208
1138 if (ip [3] == CMD_IP_RST) 1209 if (ip [3] == CMD_IP_RST)
1139 { 1210 {
1140 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1211 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1141 1212
1142 delete dns; c->dns = 0; 1213 dns->reset ();
1143
1144 return; 1214 return;
1145 } 1215 }
1146 else if (ip [3] == CMD_IP_SYN) 1216 else if (ip [3] == CMD_IP_SYN)
1147 { 1217 {
1148 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1218 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1149 dns->established = true; 1219 dns->established = true;
1150 } 1220 }
1221 else if (ip [3] == CMD_IP_CSE)
1222 {
1223 if (conf.dns_case_preserving)
1224 {
1225 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1226 conf.dns_case_preserving = false;
1227 dns->reset ();
1228 return;
1229 }
1230 else
1231 {
1232 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1233 dns->established = true;
1234 }
1235 }
1151 else if (ip [3] == CMD_IP_REJ) 1236 else if (ip [3] == CMD_IP_REJ)
1152 { 1237 {
1153 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1238 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1154 abort (); 1239 dns->tw.start (60.);
1155 } 1240 }
1156 else 1241 else
1242 {
1157 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1243 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1244 dns->tw.start (60.);
1245 }
1158 } 1246 }
1159 else 1247 else
1160 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1248 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1161 ip [0], ip [1], ip [2], ip [3]); 1249 ip [0], ip [1], ip [2], ip [3]);
1162 1250
… …
1224 1312
1225 if (!c->dns) 1313 if (!c->dns)
1226 c->dns = new dns_connection (c); 1314 c->dns = new dns_connection (c);
1227 1315
1228 if (c->dns->snddq.put (pkt)) 1316 if (c->dns->snddq.put (pkt))
1317 {
1318 min_it (c->dns->poll_interval, 0.25);
1229 c->dns->tw (); 1319 c->dns->tw ();
1320 }
1230 1321
1231 // always return true even if the buffer overflows 1322 // always return true even if the buffer overflows
1232 return true; 1323 return true;
1233} 1324}
1234
1235void
1236connection::dnsv4_reset_connection ()
1237{
1238 //delete dns; dns = 0; //TODO
1239}
1240
1241#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1242 1325
1243void 1326void
1244dns_connection::time_cb (ev::timer &w, int revents) 1327dns_connection::time_cb (ev::timer &w, int revents)
1245{ 1328{
1246 // servers have to be polled 1329 // servers have to be polled
1247 if (THISNODE->dns_port) 1330 if (THISNODE->dns_port)
1248 return; 1331 return;
1249 1332
1250 // check for timeouts and (re)transmit 1333 // check for timeouts and (re)transmit
1251 tstamp next = ev::now () + poll_interval; 1334 tstamp next = 86400 * 365;
1252 dns_snd *send = 0; 1335 dns_snd *send = 0;
1253 1336
1254 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1337 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1255 i != vpn->dns_sndpq.end (); 1338 i != vpn->dns_sndpq.end ();
1256 ++i) 1339 ++i)
… …
1262 if (!send) 1345 if (!send)
1263 { 1346 {
1264 send = r; 1347 send = r;
1265 1348
1266 r->retry++; 1349 r->retry++;
1267 r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); 1350 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1268 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D 1351 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1269 1352
1270 // the following code changes the query section a bit, forcing 1353 // the following code changes the query section a bit, forcing
1271 // the forwarder to generate a new request 1354 // the forwarder to generate a new request
1272 if (r->stdhdr) 1355 if (r->stdhdr)
1273 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1356 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1274 } 1357 }
1275 } 1358 }
1276 else 1359 else
1277 NEXT (r->timeout); 1360 min_it (next, r->timeout - ev_now ());
1278 } 1361 }
1279 1362
1280 if (!send) 1363 if (!send)
1281 { 1364 {
1282 // generate a new packet, if wise 1365 // generate a new packet, if wise
… …
1286 if (vpn->dns_sndpq.empty ()) 1369 if (vpn->dns_sndpq.empty ())
1287 { 1370 {
1288 send = new dns_snd (this); 1371 send = new dns_snd (this);
1289 1372
1290 cfg.reset (THISNODE->id); 1373 cfg.reset (THISNODE->id);
1374 set_cfg ();
1291 send->gen_syn_req (); 1375 send->gen_syn_req ();
1292 } 1376 }
1293 } 1377 }
1294 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1378 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1295 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1379 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1296 { 1380 {
1297 if (last_sent + send_interval <= ev_now ()) 1381 if (last_sent + send_interval <= ev_now ())
1298 { 1382 {
1299 //printf ("sending data request etc.\n"); //D 1383 //printf ("sending data request etc.\n"); //D
1300 if (!snddq.empty () || last_received + 1. > ev_now ()) 1384 if (!snddq.empty ())
1301 {
1302 poll_interval = send_interval; 1385 min_it (next, send_interval);
1303 NEXT (ev_now () + send_interval);
1304 }
1305 1386
1306 send = new dns_snd (this); 1387 send = new dns_snd (this);
1307 send->gen_stream_req (sndseq, snddq); 1388 send->gen_stream_req (sndseq, snddq);
1308 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; 1389 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1309 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D 1390 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1310 1391
1311 sndseq = (sndseq + 1) & SEQNO_MASK; 1392 sndseq = (sndseq + 1) & SEQNO_MASK;
1312 } 1393 }
1313 else 1394 else
1314 NEXT (last_sent + send_interval); 1395 min_it (next, last_sent + send_interval - ev_now ());
1315 } 1396 }
1316 1397
1317 if (send) 1398 if (send)
1318 vpn->dns_sndpq.push_back (send); 1399 vpn->dns_sndpq.push_back (send);
1319 } 1400 }
… …
1324 sendto (vpn->dnsv4_fd, 1405 sendto (vpn->dnsv4_fd,
1325 send->pkt->at (0), send->pkt->len, 0, 1406 send->pkt->at (0), send->pkt->len, 0,
1326 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1407 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1327 } 1408 }
1328 1409
1410 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1411
1329 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1412 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1330 poll_interval, send_interval, next - ev_now (), 1413 poll_interval, send_interval, next - ev_now (),
1331 vpn->dns_sndpq.size (), snddq.size (), 1414 vpn->dns_sndpq.size (), snddq.size (),
1332 rcvpq.size ()); 1415 rcvpq.size ());
1333 1416
1334 // TODO: no idea when this happens, but when next < ev_now (), we have a problem 1417 w.start (next);
1335 // doesn't seem to happen anymore
1336 if (next < ev_now () + 0.001)
1337 next = ev_now () + 0.1;
1338
1339 w.start (next - ev_now ());
1340} 1418}
1341 1419
1342#endif 1420#endif
1343 1421

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