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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.50 by root, Sun Mar 6 13:49:50 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 };
… …
123 137
124 enc [size] = c; 138 enc [size] = c;
125 dec [(u8)c] = size; 139 dec [(u8)c] = size;
126 140
127 // allow lowercase/uppercase aliases if possible 141 // allow lowercase/uppercase aliases if possible
128 if (c >= 'A' && c <= 'Z' && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size; 142 if (is_uc (c) && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size;
129 if (c >= 'a' && c <= 'z' && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size; 143 if (is_lc (c) && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size;
130 } 144 }
131 145
132 assert (size < 256); 146 assert (size < 256);
133} 147}
134 148
… …
141{ 155{
142 charmap cmap; 156 charmap cmap;
143 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
144 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
145 159
146 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
147 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
148 162
149 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
150 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
151 165
152 basecoder (const char *cmap); 166 basecoder (const char *cmap);
153}; 167};
154 168
155basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
… …
175 dec_len [n] = len; 189 dec_len [n] = len;
176 } 190 }
177} 191}
178 192
179unsigned int 193unsigned int
180basecoder::encode_len (unsigned int len) 194basecoder::encode_len (unsigned int len) const
181{ 195{
182 return enc_len [len]; 196 return enc_len [len];
183} 197}
184 198
185unsigned int 199unsigned int
186basecoder::decode_len (unsigned int len) 200basecoder::decode_len (unsigned int len) const
187{ 201{
188 while (len && !dec_len [len]) 202 while (len && !dec_len [len])
189 --len; 203 --len;
190 204
191 return dec_len [len]; 205 return dec_len [len];
192} 206}
193 207
194unsigned int 208unsigned int
195basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
196{ 210{
197 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
198 return 0; 212 return 0;
199 213
200 int elen = encode_len (len); 214 int elen = encode_len (len);
… …
220 234
221 return elen; 235 return elen;
222} 236}
223 237
224unsigned int 238unsigned int
225basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
226{ 240{
227 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
228 return 0; 242 return 0;
229 243
230 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
… …
279 } 293 }
280 abort (); 294 abort ();
281} 295}
282#endif 296#endif
283 297
284//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
285//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
286static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
287//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
288static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
289 301
290///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
291 303
292#define HDRSIZE 6 304#define HDRSIZE 5
293 305
294inline void 306inline void
295encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
296{ 308{
309 assert (clientid < 256);
310
297 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
298 312
299 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
300 clientid, 316 clientid,
301 (seqno >> 8) | (retry << 6),
302 seqno,
303 }; 317 };
304 318
305 assert (clientid < 256);
306
307 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
308} 320}
309 321
310inline void 322inline void
311decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
312{ 324{
313 u8 hdr[3]; 325 u8 hdr[3];
314 326
315 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
316 328
317 clientid = hdr[0]; 329 clientid = hdr[2];
318 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
319} 331}
320 332
321///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
322 334
323struct byte_stream 335struct byte_stream
… …
436 448
437struct dns_cfg 449struct dns_cfg
438{ 450{
439 static int next_uid; 451 static int next_uid;
440 452
441 u8 id1, id2, id3, id4; 453 u8 chksum;
454 u8 rrtype;
455 u16 uid; // to make request unique
442 456
443 u8 version; 457 u8 version;
444 u8 flags; 458 u8 flags;
445 u8 rrtype; 459 u16 max_size;
460
461 u8 id1, id2, id3, id4;
462
463 u16 client;
446 u8 def_ttl; 464 u8 def_ttl;
465 u8 r0;
447 466
448 u16 client; 467 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
449 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
450 471
451 u16 max_size;
452 u8 seq_cdc;
453 u8 req_cdc;
454
455 u8 rep_cdc;
456 u8 delay; // time in 0.01s units that the server may delay replying packets
457 u8 r3, r4;
458
459 u8 r5, r6, r7, r8; 472 u8 r1, r2, r3, r4;
460 473
461 void reset (int clientid); 474 void reset (int clientid);
462 bool valid (); 475 bool valid ();
476 u8 get_chksum ();
463}; 477};
464 478
465int dns_cfg::next_uid; 479int dns_cfg::next_uid;
466 480
467void 481void
468dns_cfg::reset (int clientid) 482dns_cfg::reset (int clientid)
469{ 483{
484 // this ID must result in some mixed-case characters in cdc26-encoding
470 id1 = 'G'; 485 id1 = 'G';
471 id2 = 'V'; 486 id2 = 'V';
472 id3 = 'P'; 487 id3 = 'P';
473 id4 = 'E'; 488 id4 = 'E';
474 489
475 version = 1; 490 version = 2;
476 491
477 rrtype = RR_TYPE_TXT; 492 rrtype = RR_TYPE_TXT;
478 flags = 0; 493 flags = 0;
479 def_ttl = 0; 494 def_ttl = 0;
480 seq_cdc = 26; 495 syn_cdc = 26;
481 req_cdc = 62; 496 hdr_cdc = 36;
497 req_cdc = conf.dns_case_preserving ? 62 : 36;
482 rep_cdc = 0; 498 rep_cdc = 0;
483 max_size = htons (MAX_PKT_SIZE); 499 max_size = htons (MAX_PKT_SIZE);
484 client = htons (clientid); 500 client = htons (clientid);
485 uid = next_uid++; 501 uid = ++next_uid;
486 delay = 0;
487 502
488 r3 = r4 = 0; 503 r0 = r1 = r2 = r3 = r4 = 0;
489 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);
490} 523}
491 524
492bool 525bool
493dns_cfg::valid () 526dns_cfg::valid ()
494{ 527{
… …
496 // only the following encoding/decoding settings are implemented. 529 // only the following encoding/decoding settings are implemented.
497 return id1 == 'G' 530 return id1 == 'G'
498 && id2 == 'V' 531 && id2 == 'V'
499 && id3 == 'P' 532 && id3 == 'P'
500 && id4 == 'E' 533 && id4 == 'E'
534 && version == 2
501 && seq_cdc == 26 535 && syn_cdc == 26
502 && req_cdc == 62 536 && hdr_cdc == 36
537 && (req_cdc == 36 || req_cdc == 62)
503 && rep_cdc == 0 538 && rep_cdc == 0
504 && version == 1; 539 && chksum == get_chksum ();
505} 540}
506 541
507struct dns_packet : net_packet 542struct dns_packet : net_packet
508{ 543{
509 u16 id; 544 u16 id;
… …
555static 590static
556u16 next_id () 591u16 next_id ()
557{ 592{
558 static u16 dns_id = 0; // TODO: should be per-vpn 593 static u16 dns_id = 0; // TODO: should be per-vpn
559 594
595#if 1
560 if (!dns_id) 596 if (!dns_id)
561 dns_id = time (0); 597 dns_id = time (0);
562 598
563 // the simplest lsfr with periodicity 65535 i could find 599 // the simplest lsfr with periodicity 65535 i could find
564 dns_id = (dns_id << 1) 600 dns_id = (dns_id << 1)
… …
566 ^ (dns_id >> 2) 602 ^ (dns_id >> 2)
567 ^ (dns_id >> 4) 603 ^ (dns_id >> 4)
568 ^ (dns_id >> 15)) & 1); 604 ^ (dns_id >> 15)) & 1);
569 605
570 return dns_id; 606 return dns_id;
607#else
608 dns_id++;//D
609
610 return htons (dns_id);
611#endif
571} 612}
572 613
573struct dns_rcv; 614struct dns_rcv;
574struct dns_snd; 615struct dns_snd;
575 616
… …
579 struct vpn *vpn; 620 struct vpn *vpn;
580 621
581 dns_cfg cfg; 622 dns_cfg cfg;
582 623
583 bool established; 624 bool established;
625 const basecoder *cdc;
584 626
585 tstamp last_received; 627 tstamp last_received;
586 tstamp last_sent; 628 tstamp last_sent;
587 double min_latency; 629 double min_latency;
588 double poll_interval, send_interval; 630 double poll_interval, send_interval;
… …
592 byte_stream rcvdq; int rcvseq; int repseq; 634 byte_stream rcvdq; int rcvseq; int repseq;
593 byte_stream snddq; int sndseq; 635 byte_stream snddq; int sndseq;
594 636
595 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;
596 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
597 642
598 dns_connection (connection *c); 643 dns_connection (connection *c);
599 ~dns_connection (); 644 ~dns_connection ();
600}; 645};
601 646
… …
675 // 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
676 721
677 char enc[256], *encp = enc; 722 char enc[256], *encp = enc;
678 encode_header (enc, THISNODE->id, seqno); 723 encode_header (enc, THISNODE->id, seqno);
679 724
680 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);
681 726
682 if (datalen > stream.size ()) 727 if (datalen > stream.size ())
683 datalen = stream.size (); 728 datalen = stream.size ();
684 729
685 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 730 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
686 stream.remove (datalen); 731 stream.remove (datalen);
687 732
688 while (enclen) 733 while (enclen)
689 { 734 {
690 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 735 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
… …
763{ 808{
764 tw.set<dns_connection, &dns_connection::time_cb> (this); 809 tw.set<dns_connection, &dns_connection::time_cb> (this);
765 810
766 vpn = c->vpn; 811 vpn = c->vpn;
767 812
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
768 established = false; 837 established = false;
769 838
770 rcvseq = repseq = sndseq = 0; 839 rcvseq = repseq = sndseq = 0;
771 840
772 last_sent = last_received = 0; 841 last_sent = 0;
773 poll_interval = 0.5; // starting here 842 poll_interval = 0.5; // starting here
774 send_interval = 0.5; // starting rate 843 send_interval = 0.5; // starting rate
775 min_latency = INITIAL_TIMEOUT; 844 min_latency = INITIAL_TIMEOUT;
776} 845}
777 846
778dns_connection::~dns_connection () 847void
848dns_connection::set_cfg ()
779{ 849{
780 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 850 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
781 i != rcvpq.end ();
782 ++i)
783 delete *i;
784} 851}
785 852
786void 853void
787dns_connection::receive_rep (dns_rcv *r) 854dns_connection::receive_rep (dns_rcv *r)
788{ 855{
789 if (r->datalen) 856 if (r->datalen)
790 { 857 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
791 last_received = ev_now ();
792 tw ();
793
794 poll_interval = send_interval;
795 }
796 else 858 else
797 { 859 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
798 poll_interval *= 1.5;
799
800 if (poll_interval > MAX_POLL_INTERVAL)
801 poll_interval = MAX_POLL_INTERVAL;
802 }
803 860
804 rcvpq.push_back (r); 861 rcvpq.push_back (r);
805 862
806 redo: 863 redo:
807 864
… …
827 884
828 if (!rcvdq.put (r->data, r->datalen)) 885 if (!rcvdq.put (r->data, r->datalen))
829 { 886 {
830 // MUST never overflow, can be caused by data corruption, TODO 887 // MUST never overflow, can be caused by data corruption, TODO
831 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)"); 888 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
832 c->dnsv4_reset_connection (); 889 reset ();
833 return; 890 return;
834 } 891 }
835 892
836 while (vpn_packet *pkt = rcvdq.get ()) 893 while (vpn_packet *pkt = rcvdq.get ())
837 { 894 {
… …
889 { 946 {
890 // correct class, domain: parse 947 // correct class, domain: parse
891 int client, seqno; 948 int client, seqno;
892 decode_header (qname, client, seqno); 949 decode_header (qname, client, seqno);
893 950
894 u8 data[MAXSIZE];
895 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
896
897 if (0 < client && client <= conns.size ()) 951 if (0 < client && client <= conns.size ())
898 { 952 {
899 connection *c = conns [client - 1]; 953 connection *c = conns [client - 1];
900 dns_connection *dns = c->dns; 954 dns_connection *dns = c->dns;
901 dns_rcv *rcv; 955 dns_rcv *rcv;
902 956
903 if (dns) 957 if (dns)
904 { 958 {
959 u8 data[MAXSIZE];
960 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
961
905 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 (); )
906 if (SEQNO_EQ ((*i)->seqno, seqno)) 963 if (SEQNO_EQ ((*i)->seqno, seqno))
907 { 964 {
908 // already seen that request: simply reply with the cached reply 965 // already seen that request: simply reply with the cached reply
909 dns_rcv *r = *i; 966 dns_rcv *r = *i;
… …
1010 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
1011 pkt [offs++] = 0; pkt [offs++] = 0; 1068 pkt [offs++] = 0; pkt [offs++] = 0;
1012 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1069 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
1013 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1070 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
1014 1071
1015 slog (L_INFO, _("DNS: client %d connects"), client);
1016
1017 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;
1018 pkt [offs++] = CMD_IP_REJ; 1073 pkt [offs++] = CMD_IP_REJ;
1019 1074
1020 if (0 < client && client <= conns.size ()) 1075 if (0 < client && client <= conns.size ())
1021 { 1076 {
1022 connection *c = conns [client - 1]; 1077 connection *c = conns [client - 1];
1023 1078
1024 if (cfg.valid ()) 1079 if (cfg.valid ())
1025 { 1080 {
1026 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));
1027 1086
1028 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
1029 c->dns = new dns_connection (c); 1092 c->dns = new dns_connection (c);
1030 c->dns->cfg = cfg; 1093 c->dns->cfg = cfg;
1094 c->dns->set_cfg ();
1031 } 1095 }
1032 } 1096 }
1033 } 1097 }
1034 } 1098 }
1035 1099
… …
1106 ttl |= pkt [offs++] << 16; 1170 ttl |= pkt [offs++] << 16;
1107 ttl |= pkt [offs++] << 8; 1171 ttl |= pkt [offs++] << 8;
1108 ttl |= pkt [offs++]; 1172 ttl |= pkt [offs++];
1109 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1173 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1110 1174
1111 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1175 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1112 { 1176 {
1113 if (rdlen <= MAXSIZE - offs) 1177 if (rdlen <= MAXSIZE - offs)
1114 { 1178 {
1115 // decode bytes, finally 1179 // decode bytes, finally
1116 1180
… …
1142 { 1206 {
1143 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1207 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1144 1208
1145 if (ip [3] == CMD_IP_RST) 1209 if (ip [3] == CMD_IP_RST)
1146 { 1210 {
1147 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1211 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1148 1212
1149 c->dnsv4_reset_connection (); 1213 dns->reset ();
1214 return;
1150 } 1215 }
1151 else if (ip [3] == CMD_IP_SYN) 1216 else if (ip [3] == CMD_IP_SYN)
1152 { 1217 {
1153 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1218 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1154 dns->established = true; 1219 dns->established = true;
1155 } 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 }
1156 else if (ip [3] == CMD_IP_REJ) 1236 else if (ip [3] == CMD_IP_REJ)
1237 {
1157 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us.")); 1238 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1239 dns->tw.start (60.);
1240 }
1158 else 1241 else
1242 {
1159 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 }
1160 } 1246 }
1161 else 1247 else
1162 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"),
1163 ip [0], ip [1], ip [2], ip [3]); 1249 ip [0], ip [1], ip [2], ip [3]);
1164 1250
… …
1226 1312
1227 if (!c->dns) 1313 if (!c->dns)
1228 c->dns = new dns_connection (c); 1314 c->dns = new dns_connection (c);
1229 1315
1230 if (c->dns->snddq.put (pkt)) 1316 if (c->dns->snddq.put (pkt))
1317 {
1318 min_it (c->dns->poll_interval, 0.25);
1231 c->dns->tw (); 1319 c->dns->tw ();
1320 }
1232 1321
1233 // always return true even if the buffer overflows 1322 // always return true even if the buffer overflows
1234 return true; 1323 return true;
1235} 1324}
1236
1237void
1238connection::dnsv4_reset_connection ()
1239{
1240 //delete dns; dns = 0; //TODO
1241}
1242
1243#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1244 1325
1245void 1326void
1246dns_connection::time_cb (ev::timer &w, int revents) 1327dns_connection::time_cb (ev::timer &w, int revents)
1247{ 1328{
1248 // servers have to be polled 1329 // servers have to be polled
1249 if (THISNODE->dns_port) 1330 if (THISNODE->dns_port)
1250 return; 1331 return;
1251 1332
1252 // check for timeouts and (re)transmit 1333 // check for timeouts and (re)transmit
1253 tstamp next = ev::now () + poll_interval; 1334 tstamp next = 86400 * 365;
1254 dns_snd *send = 0; 1335 dns_snd *send = 0;
1255 1336
1256 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1337 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1257 i != vpn->dns_sndpq.end (); 1338 i != vpn->dns_sndpq.end ();
1258 ++i) 1339 ++i)
… …
1264 if (!send) 1345 if (!send)
1265 { 1346 {
1266 send = r; 1347 send = r;
1267 1348
1268 r->retry++; 1349 r->retry++;
1269 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;
1270 //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
1271 1352
1272 // the following code changes the query section a bit, forcing 1353 // the following code changes the query section a bit, forcing
1273 // the forwarder to generate a new request 1354 // the forwarder to generate a new request
1274 if (r->stdhdr) 1355 if (r->stdhdr)
1275 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);
1276 } 1357 }
1277 } 1358 }
1278 else 1359 else
1279 NEXT (r->timeout); 1360 min_it (next, r->timeout - ev_now ());
1280 } 1361 }
1281 1362
1282 if (!send) 1363 if (!send)
1283 { 1364 {
1284 // generate a new packet, if wise 1365 // generate a new packet, if wise
… …
1288 if (vpn->dns_sndpq.empty ()) 1369 if (vpn->dns_sndpq.empty ())
1289 { 1370 {
1290 send = new dns_snd (this); 1371 send = new dns_snd (this);
1291 1372
1292 cfg.reset (THISNODE->id); 1373 cfg.reset (THISNODE->id);
1374 set_cfg ();
1293 send->gen_syn_req (); 1375 send->gen_syn_req ();
1294 } 1376 }
1295 } 1377 }
1296 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1378 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1297 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1379 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1298 { 1380 {
1299 if (last_sent + send_interval <= ev_now ()) 1381 if (last_sent + send_interval <= ev_now ())
1300 { 1382 {
1301 //printf ("sending data request etc.\n"); //D 1383 //printf ("sending data request etc.\n"); //D
1302 if (!snddq.empty () || last_received + 1. > ev_now ()) 1384 if (!snddq.empty ())
1303 {
1304 poll_interval = send_interval; 1385 min_it (next, send_interval);
1305 NEXT (ev_now () + send_interval);
1306 }
1307 1386
1308 send = new dns_snd (this); 1387 send = new dns_snd (this);
1309 send->gen_stream_req (sndseq, snddq); 1388 send->gen_stream_req (sndseq, snddq);
1310 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; 1389 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1311 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D 1390 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1312 1391
1313 sndseq = (sndseq + 1) & SEQNO_MASK; 1392 sndseq = (sndseq + 1) & SEQNO_MASK;
1314 } 1393 }
1315 else 1394 else
1316 NEXT (last_sent + send_interval); 1395 min_it (next, last_sent + send_interval - ev_now ());
1317 } 1396 }
1318 1397
1319 if (send) 1398 if (send)
1320 vpn->dns_sndpq.push_back (send); 1399 vpn->dns_sndpq.push_back (send);
1321 } 1400 }
… …
1326 sendto (vpn->dnsv4_fd, 1405 sendto (vpn->dnsv4_fd,
1327 send->pkt->at (0), send->pkt->len, 0, 1406 send->pkt->at (0), send->pkt->len, 0,
1328 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1407 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1329 } 1408 }
1330 1409
1410 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1411
1331 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)",
1332 poll_interval, send_interval, next - ev_now (), 1413 poll_interval, send_interval, next - ev_now (),
1333 vpn->dns_sndpq.size (), snddq.size (), 1414 vpn->dns_sndpq.size (), snddq.size (),
1334 rcvpq.size ()); 1415 rcvpq.size ());
1335 1416
1336 // TODO: no idea when this happens, but when next < ev_now (), we have a problem 1417 w.start (next);
1337 // doesn't seem to happen anymore
1338 if (next < ev_now () + 0.001)
1339 next = ev_now () + 0.1;
1340
1341 w.start (next - ev_now ());
1342} 1418}
1343 1419
1344#endif 1420#endif
1345 1421

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