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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.42 by pcg, Sat Nov 10 05:14:22 2007 UTC vs.
Revision 1.56 by root, Tue Oct 18 13:24:01 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) 2003-2005 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 7 GVPE is free software; you can redistribute it and/or modify it
8 it under the terms of the GNU General Public License as published by 8 under the terms of the GNU General Public License as published by the
9 the Free Software Foundation; either version 2 of the License, or 9 Free Software Foundation; either version 3 of the License, or (at your
10 (at your option) any later version. 10 option) any later version.
11 11
12 This program is distributed in the hope that it will be useful, 12 This program is distributed in the hope that it will be useful, but
13 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15 GNU General Public License for more details. 15 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 along
18 along with gvpe; if not, write to the Free Software 18 with this program; if not, see <http://www.gnu.org/licenses/>.
19 Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19
20 Additional permission under GNU GPL version 3 section 7
21
22 If you modify this Program, or any covered work, by linking or
23 combining it with the OpenSSL project's OpenSSL library (or a modified
24 version of that library), containing parts covered by the terms of the
25 OpenSSL or SSLeay licenses, the licensors of this Program grant you
26 additional permission to convey the resulting work. Corresponding
27 Source for a non-source form of such a combination shall include the
28 source code for the parts of OpenSSL used as well as that of the
29 covered work.
20*/ 30*/
21 31
22// TODO: EDNS0 option to increase dns mtu? 32// TODO: EDNS0 option to increase dns mtu?
23// TODO: re-write dns packet parsing/creation using a safe mem-buffer 33// TODO: re-write dns packet parsing/creation using a safe mem-buffer
24// to ensure no buffer overflows or similar problems. 34// to ensure no buffer overflows or similar problems.
42#include <unistd.h> 52#include <unistd.h>
43#include <fcntl.h> 53#include <fcntl.h>
44 54
45#include <map> 55#include <map>
46 56
57#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
47#include <gmp.h> 58#include <gmp.h>
48 59
49#include "netcompat.h" 60#include "netcompat.h"
50 61
51#include "vpn.h" 62#include "vpn.h"
52 63
64#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received
53#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
54#define ACTIVITY_INTERVAL 5.
55 66
56#define INITIAL_TIMEOUT 0.1 // retry timeouts 67#define INITIAL_TIMEOUT 0.1 // retry timeouts
57#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn 68#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
58 69
59#define MAX_SEND_INTERVAL 2. // optimistic? 70#define MAX_SEND_INTERVAL 5. // optimistic?
60 71
61#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 72#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
62#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
63 74
64#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
65// 240 leaves about 4 bytes of server reply data 76// 240 leaves about 4 bytes of server reply data
66// every request byte less give room for two reply bytes 77// every request byte less give room for two reply bytes
67 78
68#define SEQNO_MASK 0x3fff 79#define SEQNO_MASK 0x3fff
69#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 80#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
72#define MAX_PKT_SIZE 512 83#define MAX_PKT_SIZE 512
73 84
74#define RR_TYPE_A 1 85#define RR_TYPE_A 1
75#define RR_TYPE_NULL 10 86#define RR_TYPE_NULL 10
76#define RR_TYPE_TXT 16 87#define RR_TYPE_TXT 16
88#define RR_TYPE_AAAA 28
77#define RR_TYPE_ANY 255 89#define RR_TYPE_ANY 255
78 90
79#define RR_CLASS_IN 1 91#define RR_CLASS_IN 1
80 92
81#define CMD_IP_1 207 93#define CMD_IP_1 207
82#define CMD_IP_2 46 94#define CMD_IP_2 46
83#define CMD_IP_3 236 95#define CMD_IP_3 236
84#define CMD_IP_RST 29 96
85#define CMD_IP_SYN 113 97#define CMD_IP_RST 29 // some error, reset and retry
86#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}
87 113
88// works for cmaps up to 255 (not 256!) 114// works for cmaps up to 255 (not 256!)
89struct charmap 115struct charmap
90{ 116{
91 enum { INVALID = (u8)255 }; 117 enum { INVALID = (u8)255 };
105 memset (enc, (char) 0, 256); 131 memset (enc, (char) 0, 256);
106 memset (dec, (char)INVALID, 256); 132 memset (dec, (char)INVALID, 256);
107 133
108 for (size = 0; cmap [size]; size++) 134 for (size = 0; cmap [size]; size++)
109 { 135 {
136 char c = cmap [size];
137
110 enc [size] = cmap [size]; 138 enc [size] = c;
111 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;
112 } 144 }
113 145
114 assert (size < 256); 146 assert (size < 256);
115} 147}
116 148
117#define MAX_DEC_LEN 500 149#define MAX_DEC_LEN 500
118#define MAX_ENC_LEN (MAX_DEC_LEN * 2) 150#define MAX_ENC_LEN (MAX_DEC_LEN * 2)
119#define MAX_LIMBS ((MAX_DEC_LEN * 8 + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS) 151#define MAX_LIMBS ((MAX_DEC_LEN * 8 + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS + 1)
120 152
121// ugly. minimum base is 16(!) 153// ugly. minimum base is 16(!)
122struct basecoder 154struct basecoder
123{ 155{
124 charmap cmap; 156 charmap cmap;
125 unsigned int enc_len [MAX_DEC_LEN]; 157 unsigned int enc_len [MAX_DEC_LEN];
126 unsigned int dec_len [MAX_ENC_LEN]; 158 unsigned int dec_len [MAX_ENC_LEN];
127 159
128 unsigned int encode_len (unsigned int len); 160 unsigned int encode_len (unsigned int len) const;
129 unsigned int decode_len (unsigned int len); 161 unsigned int decode_len (unsigned int len) const;
130 162
131 unsigned int encode (char *dst, u8 *src, unsigned int len); 163 unsigned int encode (char *dst, u8 *src, unsigned int len) const;
132 unsigned int decode (u8 *dst, char *src, unsigned int len); 164 unsigned int decode (u8 *dst, char *src, unsigned int len) const;
133 165
134 basecoder (const char *cmap); 166 basecoder (const char *cmap);
135}; 167};
136 168
137basecoder::basecoder (const char *cmap) 169basecoder::basecoder (const char *cmap)
138: cmap (cmap) 170: cmap (cmap)
139{ 171{
172 int decn = -1;
173
140 for (unsigned int len = 0; len < MAX_DEC_LEN; ++len) 174 for (unsigned int len = 0; len < MAX_DEC_LEN; ++len)
141 { 175 {
142 u8 src [MAX_DEC_LEN]; 176 u8 src [MAX_DEC_LEN];
143 u8 dst [MAX_ENC_LEN]; 177 u8 dst [MAX_ENC_LEN];
144 178
148 mp_size_t n; 182 mp_size_t n;
149 183
150 n = mpn_set_str (m, src, len, 256); 184 n = mpn_set_str (m, src, len, 256);
151 n = mpn_get_str (dst, this->cmap.size, m, n); 185 n = mpn_get_str (dst, this->cmap.size, m, n);
152 186
153 for (int i = 0; !dst [i]; ++i) 187 for (int i = 0; n && !dst [i]; ++i, --n)
154 n--; 188 ;
155 189
156 enc_len [len] = n; 190 enc_len [len] = n;
191 while (decn < n)
157 dec_len [n] = len; 192 dec_len [++decn] = len;
158 } 193 }
159} 194}
160 195
196unsigned int
161unsigned int basecoder::encode_len (unsigned int len) 197basecoder::encode_len (unsigned int len) const
162{ 198{
163 return enc_len [len]; 199 return enc_len [len];
164} 200}
165 201
202unsigned int
166unsigned int basecoder::decode_len (unsigned int len) 203basecoder::decode_len (unsigned int len) const
167{ 204{
168 while (len && !dec_len [len])
169 --len;
170
171 return dec_len [len]; 205 return dec_len [len];
172} 206}
173 207
208unsigned int
174unsigned int basecoder::encode (char *dst, u8 *src, unsigned int len) 209basecoder::encode (char *dst, u8 *src, unsigned int len) const
175{ 210{
176 if (!len || len > MAX_DEC_LEN) 211 if (!len || len > MAX_DEC_LEN)
177 return 0; 212 return 0;
178 213
179 int elen = encode_len (len); 214 int elen = encode_len (len);
198 *dst++ = cmap.encode [dst_ [i]]; 233 *dst++ = cmap.encode [dst_ [i]];
199 234
200 return elen; 235 return elen;
201} 236}
202 237
238unsigned int
203unsigned int basecoder::decode (u8 *dst, char *src, unsigned int len) 239basecoder::decode (u8 *dst, char *src, unsigned int len) const
204{ 240{
205 if (!len || len > MAX_ENC_LEN) 241 if (!len || len > MAX_ENC_LEN)
206 return 0; 242 return 0;
207 243
208 u8 src_ [MAX_ENC_LEN]; 244 u8 src_ [MAX_ENC_LEN];
257 } 293 }
258 abort (); 294 abort ();
259} 295}
260#endif 296#endif
261 297
262//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
263//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
264static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); 298static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9
265//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet 299static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers
266static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 300static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z
267 301
268///////////////////////////////////////////////////////////////////////////// 302/////////////////////////////////////////////////////////////////////////////
269 303
270#define HDRSIZE 6 304#define HDRSIZE 5
271 305
306inline void
272inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 307encode_header (char *data, int clientid, int seqno, int retry = 0)
273{ 308{
309 assert (clientid < 256);
310
274 seqno &= SEQNO_MASK; 311 seqno &= SEQNO_MASK;
275 312
276 u8 hdr[3] = { 313 u8 hdr[3] = {
314 seqno,
315 (seqno >> 8) | (retry << 6),
277 clientid, 316 clientid,
278 (seqno >> 8) | (retry << 6),
279 seqno,
280 }; 317 };
281 318
282 assert (clientid < 256);
283
284 cdc26.encode (data, hdr, 3); 319 cdc36.encode (data, hdr, 3);
285} 320}
286 321
322inline void
287inline void decode_header (char *data, int &clientid, int &seqno) 323decode_header (char *data, int &clientid, int &seqno)
288{ 324{
289 u8 hdr[3]; 325 u8 hdr[3];
290 326
291 cdc26.decode (hdr, data, HDRSIZE); 327 cdc36.decode (hdr, data, HDRSIZE);
292 328
293 clientid = hdr[0]; 329 clientid = hdr[2];
294 seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; 330 seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK;
295} 331}
296 332
297///////////////////////////////////////////////////////////////////////////// 333/////////////////////////////////////////////////////////////////////////////
298 334
299struct byte_stream 335struct byte_stream
325byte_stream::~byte_stream () 361byte_stream::~byte_stream ()
326{ 362{
327 delete data; 363 delete data;
328} 364}
329 365
366void
330void byte_stream::remove (int count) 367byte_stream::remove (int count)
331{ 368{
332 if (count > fill)
333 assert (count <= fill); 369 assert (count <= fill);
334 370
335 memmove (data, data + count, fill -= count); 371 memmove (data, data + count, fill -= count);
336} 372}
337 373
374bool
338bool byte_stream::put (u8 *data, unsigned int datalen) 375byte_stream::put (u8 *data, unsigned int datalen)
339{ 376{
340 if (maxsize - fill < datalen) 377 if (maxsize - fill < datalen)
341 return false; 378 return false;
342 379
343 memcpy (this->data + fill, data, datalen); fill += datalen; 380 memcpy (this->data + fill, data, datalen); fill += datalen;
344 381
345 return true; 382 return true;
346} 383}
347 384
385bool
348bool byte_stream::put (vpn_packet *pkt) 386byte_stream::put (vpn_packet *pkt)
349{ 387{
350 if (maxsize - fill < pkt->len + 2) 388 if (maxsize - fill < pkt->len + 2)
351 return false; 389 return false;
352 390
353 data [fill++] = pkt->len >> 8; 391 data [fill++] = pkt->len >> 8;
356 memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len; 394 memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
357 395
358 return true; 396 return true;
359} 397}
360 398
399vpn_packet *
361vpn_packet *byte_stream::get () 400byte_stream::get ()
362{ 401{
363 unsigned int len; 402 unsigned int len;
364 403
365 for (;;) 404 for (;;)
366 { 405 {
406 if (fill < 2)
407 return 0;
408
367 len = (data [0] << 8) | data [1]; 409 len = (data [0] << 8) | data [1];
368 410
369 if (len <= MAXSIZE || fill < 2) 411 if (len <= MAXSIZE)
370 break; 412 break;
371 413
372 // TODO: handle this better than skipping, e.g. by reset 414 // TODO: handle this better than skipping, e.g. by reset
373 slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte...")); 415 slog (L_DEBUG, _("DNS: corrupted packet (%02x %02x > %d) stream skipping a byte..."), data [0], data [1], MAXSIZE);
374 remove (1); 416 remove (1);
375 } 417 }
376 418
377 if (fill < len + 2) 419 if (fill < len + 2)
378 return 0; 420 return 0;
409 451
410struct dns_cfg 452struct dns_cfg
411{ 453{
412 static int next_uid; 454 static int next_uid;
413 455
414 u8 id1, id2, id3, id4; 456 u8 chksum;
457 u8 rrtype;
458 u16 uid; // to make request unique
415 459
416 u8 version; 460 u8 version;
417 u8 flags; 461 u8 flags;
418 u8 rrtype; 462 u16 max_size;
463
464 u8 id1, id2, id3, id4;
465
466 u16 client;
419 u8 def_ttl; 467 u8 def_ttl;
468 u8 r0;
420 469
421 u16 client; 470 u8 syn_cdc; // cdc en/decoder for syn (A?) requests
422 u16 uid; // to make request unique 471 u8 hdr_cdc; // cdc en/decoder for regular request headers
472 u8 req_cdc; // cdc en/decoder for regular (ANY?) request data
473 u8 rep_cdc; // cdc en/decoder for regular (TXT) replies, 0 == 8 bit encoding
423 474
424 u16 max_size;
425 u8 seq_cdc;
426 u8 req_cdc;
427
428 u8 rep_cdc;
429 u8 delay; // time in 0.01s units that the server may delay replying packets
430 u8 r3, r4;
431
432 u8 r5, r6, r7, r8; 475 u8 r1, r2, r3, r4;
433 476
434 void reset (int clientid); 477 void reset (int clientid);
435 bool valid (); 478 bool valid ();
479 u8 get_chksum ();
436}; 480};
437 481
438int dns_cfg::next_uid; 482int dns_cfg::next_uid;
439 483
484void
440void dns_cfg::reset (int clientid) 485dns_cfg::reset (int clientid)
441{ 486{
487 // this ID must result in some mixed-case characters in cdc26-encoding
442 id1 = 'G'; 488 id1 = 'G';
443 id2 = 'V'; 489 id2 = 'V';
444 id3 = 'P'; 490 id3 = 'P';
445 id4 = 'E'; 491 id4 = 'E';
446 492
447 version = 1; 493 version = 2;
448 494
449 rrtype = RR_TYPE_TXT; 495 rrtype = RR_TYPE_TXT;
450 flags = 0; 496 flags = 0;
451 def_ttl = 0; 497 def_ttl = 0;
452 seq_cdc = 26; 498 syn_cdc = 26;
453 req_cdc = 62; 499 hdr_cdc = 36;
500 req_cdc = conf.dns_case_preserving ? 62 : 36;
454 rep_cdc = 0; 501 rep_cdc = 0;
455 max_size = htons (MAX_PKT_SIZE); 502 max_size = htons (MAX_PKT_SIZE);
456 client = htons (clientid); 503 client = htons (clientid);
457 uid = next_uid++; 504 uid = ++next_uid;
458 delay = 0;
459 505
460 r3 = r4 = 0; 506 r0 = r1 = r2 = r3 = r4 = 0;
461 r4 = r5 = r6 = r7 = 0;
462}
463 507
508 chksum = get_chksum ();
509}
510
511// simple but not trivial chksum
512u8
513dns_cfg::get_chksum ()
514{
515 unsigned int sum = 0xff00; // only 16 bits required
516
517 u8 old_chksum = chksum;
518 chksum = 0;
519
520 for (unsigned int i = 0; i < sizeof (*this); ++i)
521 sum += ((u8 *)this)[i] * (i + 1);
522
523 chksum = old_chksum;
524
525 return sum + (sum >> 8);
526}
527
528bool
464bool dns_cfg::valid () 529dns_cfg::valid ()
465{ 530{
466 // although the protocol itself allows for some configurability, 531 // although the protocol itself allows for some configurability,
467 // only the following encoding/decoding settings are implemented. 532 // only the following encoding/decoding settings are implemented.
468 return id1 == 'G' 533 return id1 == 'G'
469 && id2 == 'V' 534 && id2 == 'V'
470 && id3 == 'P' 535 && id3 == 'P'
471 && id4 == 'E' 536 && id4 == 'E'
537 && version == 2
472 && seq_cdc == 26 538 && syn_cdc == 26
473 && req_cdc == 62 539 && hdr_cdc == 36
540 && (req_cdc == 36 || req_cdc == 62)
474 && rep_cdc == 0 541 && rep_cdc == 0
475 && version == 1; 542 && chksum == get_chksum ();
476} 543}
477 544
478struct dns_packet : net_packet 545struct dns_packet : net_packet
479{ 546{
480 u16 id; 547 u16 id;
484 u8 data [MAXSIZE - 6 * 2]; 551 u8 data [MAXSIZE - 6 * 2];
485 552
486 int decode_label (char *data, int size, int &offs); 553 int decode_label (char *data, int size, int &offs);
487}; 554};
488 555
556int
489int dns_packet::decode_label (char *data, int size, int &offs) 557dns_packet::decode_label (char *data, int size, int &offs)
490{ 558{
491 char *orig = data; 559 char *orig = data;
492 560
493 memset (data, 0, size); 561 memset (data, 0, size);
494 562
520 return data - orig; 588 return data - orig;
521} 589}
522 590
523///////////////////////////////////////////////////////////////////////////// 591/////////////////////////////////////////////////////////////////////////////
524 592
593static
594u16 next_id ()
595{
525static u16 dns_id = 0; // TODO: should be per-vpn 596 static u16 dns_id = 0; // TODO: should be per-vpn
526 597
527static u16 next_id () 598#if 1
528{
529 if (!dns_id) 599 if (!dns_id)
530 dns_id = time (0); 600 dns_id = time (0);
531 601
532 // the simplest lsfr with periodicity 65535 i could find 602 // the simplest lsfr with periodicity 65535 i could find
533 dns_id = (dns_id << 1) 603 dns_id = (dns_id << 1)
535 ^ (dns_id >> 2) 605 ^ (dns_id >> 2)
536 ^ (dns_id >> 4) 606 ^ (dns_id >> 4)
537 ^ (dns_id >> 15)) & 1); 607 ^ (dns_id >> 15)) & 1);
538 608
539 return dns_id; 609 return dns_id;
610#else
611 dns_id++;//D
612
613 return htons (dns_id);
614#endif
540} 615}
541 616
542struct dns_rcv; 617struct dns_rcv;
543struct dns_snd; 618struct dns_snd;
544 619
548 struct vpn *vpn; 623 struct vpn *vpn;
549 624
550 dns_cfg cfg; 625 dns_cfg cfg;
551 626
552 bool established; 627 bool established;
628 const basecoder *cdc;
553 629
554 tstamp last_received; 630 tstamp last_received;
555 tstamp last_sent; 631 tstamp last_sent;
556 double min_latency; 632 double min_latency;
557 double poll_interval, send_interval; 633 double poll_interval, send_interval;
559 vector<dns_rcv *> rcvpq; 635 vector<dns_rcv *> rcvpq;
560 636
561 byte_stream rcvdq; int rcvseq; int repseq; 637 byte_stream rcvdq; int rcvseq; int repseq;
562 byte_stream snddq; int sndseq; 638 byte_stream snddq; int sndseq;
563 639
564 void time_cb (ev::timer &w, int revents); ev::timer tw; 640 inline void time_cb (ev::timer &w, int revents); ev::timer tw;
565 void receive_rep (dns_rcv *r); 641 void receive_rep (dns_rcv *r);
642
643 void reset (); // quite like tcp RST
644 void set_cfg (); // to be called after any cfg changes
566 645
567 dns_connection (connection *c); 646 dns_connection (connection *c);
568 ~dns_connection (); 647 ~dns_connection ();
569}; 648};
570 649
588: dns (dns) 667: dns (dns)
589{ 668{
590 timeout = 0; 669 timeout = 0;
591 retry = 0; 670 retry = 0;
592 seqno = 0; 671 seqno = 0;
593 sent = ev::ev_now (); 672 sent = ev_now ();
594 stdhdr = false; 673 stdhdr = false;
595 674
596 pkt = new dns_packet; 675 pkt = new dns_packet;
597 676
598 pkt->id = next_id (); 677 pkt->id = next_id ();
601dns_snd::~dns_snd () 680dns_snd::~dns_snd ()
602{ 681{
603 delete pkt; 682 delete pkt;
604} 683}
605 684
685static void
606static void append_domain (dns_packet &pkt, int &offs, const char *domain) 686append_domain (dns_packet &pkt, int &offs, const char *domain)
607{ 687{
608 // add tunnel domain 688 // add tunnel domain
609 for (;;) 689 for (;;)
610 { 690 {
611 const char *end = strchr (domain, '.'); 691 const char *end = strchr (domain, '.');
624 704
625 domain = end + 1; 705 domain = end + 1;
626 } 706 }
627} 707}
628 708
709void
629void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 710dns_snd::gen_stream_req (int seqno, byte_stream &stream)
630{ 711{
631 stdhdr = true; 712 stdhdr = true;
632 this->seqno = seqno; 713 this->seqno = seqno;
633 714
634 timeout = ev::ev_now () + INITIAL_TIMEOUT; 715 timeout = ev_now () + INITIAL_TIMEOUT;
635 716
636 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 717 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
637 pkt->qdcount = htons (1); 718 pkt->qdcount = htons (1);
638 719
639 int offs = 6*2; 720 int offs = 6*2;
642 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 723 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
643 724
644 char enc[256], *encp = enc; 725 char enc[256], *encp = enc;
645 encode_header (enc, THISNODE->id, seqno); 726 encode_header (enc, THISNODE->id, seqno);
646 727
647 int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); 728 int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
648 729
649 if (datalen > stream.size ()) 730 if (datalen > stream.size ())
650 datalen = stream.size (); 731 datalen = stream.size ();
651 732
652 int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; 733 int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
653 stream.remove (datalen); 734 stream.remove (datalen);
654 735
655 while (enclen) 736 while (enclen)
656 { 737 {
657 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; 738 int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
672 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 753 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
673 754
674 pkt->len = offs; 755 pkt->len = offs;
675} 756}
676 757
758void
677void dns_snd::gen_syn_req () 759dns_snd::gen_syn_req ()
678{ 760{
679 timeout = ev::ev_now () + INITIAL_SYN_TIMEOUT; 761 timeout = ev_now () + INITIAL_SYN_TIMEOUT;
680 762
681 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 763 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
682 pkt->qdcount = htons (1); 764 pkt->qdcount = htons (1);
683 765
684 int offs = 6 * 2; 766 int offs = 6 * 2;
724 806
725dns_connection::dns_connection (connection *c) 807dns_connection::dns_connection (connection *c)
726: c (c) 808: c (c)
727, rcvdq (MAX_BACKLOG * 2) 809, rcvdq (MAX_BACKLOG * 2)
728, snddq (MAX_BACKLOG) 810, snddq (MAX_BACKLOG)
729, tw (this, &dns_connection::time_cb)
730{ 811{
812 tw.set<dns_connection, &dns_connection::time_cb> (this);
813
731 vpn = c->vpn; 814 vpn = c->vpn;
732 815
816 reset ();
817}
818
819dns_connection::~dns_connection ()
820{
821 reset ();
822}
823
824void
825dns_connection::reset ()
826{
827 while (!rcvpq.empty ())
828 {
829 delete rcvpq.back ();
830 rcvpq.pop_back ();
831 }
832
833 for (int i = vpn->dns_sndpq.size (); i--; )
834 if (vpn->dns_sndpq [i]->dns == this)
835 {
836 vpn->dns_sndpq [i] = vpn->dns_sndpq.back ();
837 vpn->dns_sndpq.pop_back ();
838 }
839
733 established = false; 840 established = false;
734 841
735 rcvseq = repseq = sndseq = 0; 842 rcvseq = repseq = sndseq = 0;
736 843
737 last_sent = last_received = 0; 844 last_sent = 0;
738 poll_interval = 0.5; // starting here 845 poll_interval = 0.5; // starting here
739 send_interval = 0.5; // starting rate 846 send_interval = 0.5; // starting rate
740 min_latency = INITIAL_TIMEOUT; 847 min_latency = INITIAL_TIMEOUT;
741} 848}
742 849
743dns_connection::~dns_connection () 850void
851dns_connection::set_cfg ()
744{ 852{
745 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 853 cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62;
746 i != rcvpq.end ();
747 ++i)
748 delete *i;
749} 854}
750 855
856void
751void dns_connection::receive_rep (dns_rcv *r) 857dns_connection::receive_rep (dns_rcv *r)
752{ 858{
753 if (r->datalen) 859 if (r->datalen)
754 { 860 poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL);
755 last_received = ev::ev_now ();
756 tw ();
757
758 poll_interval = send_interval;
759 }
760 else 861 else
761 { 862 poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL);
762 poll_interval *= 1.5;
763
764 if (poll_interval > MAX_POLL_INTERVAL)
765 poll_interval = MAX_POLL_INTERVAL;
766 }
767 863
768 rcvpq.push_back (r); 864 rcvpq.push_back (r);
769 865
770 redo: 866 redo:
771 867
789 885
790 rcvseq = (rcvseq + 1) & SEQNO_MASK; 886 rcvseq = (rcvseq + 1) & SEQNO_MASK;
791 887
792 if (!rcvdq.put (r->data, r->datalen)) 888 if (!rcvdq.put (r->data, r->datalen))
793 { 889 {
890 // MUST never overflow, can be caused by data corruption, TODO
794 slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); 891 slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)");
795 abort (); // MUST never overflow, can be caused by data corruption, TODO 892 reset ();
893 return;
796 } 894 }
797 895
798 while (vpn_packet *pkt = rcvdq.get ()) 896 while (vpn_packet *pkt = rcvdq.get ())
799 { 897 {
800 sockinfo si; 898 sockinfo si;
801 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; 899 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
802 900
803 vpn->recv_vpn_packet (pkt, si); 901 vpn->recv_vpn_packet (pkt, si);
804
805 delete pkt; 902 delete pkt;
806 } 903 }
807 904
808 // check for further packets 905 // check for further packets
809 goto redo; 906 goto redo;
852 { 949 {
853 // correct class, domain: parse 950 // correct class, domain: parse
854 int client, seqno; 951 int client, seqno;
855 decode_header (qname, client, seqno); 952 decode_header (qname, client, seqno);
856 953
857 u8 data[MAXSIZE];
858 int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
859
860 if (0 < client && client <= conns.size ()) 954 if (0 < client && client <= conns.size ())
861 { 955 {
862 connection *c = conns [client - 1]; 956 connection *c = conns [client - 1];
863 dns_connection *dns = c->dns; 957 dns_connection *dns = c->dns;
864 dns_rcv *rcv; 958 dns_rcv *rcv;
865 959
866 if (dns) 960 if (dns)
867 { 961 {
962 u8 data[MAXSIZE];
963 int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
964
868 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 965 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
869 if (SEQNO_EQ ((*i)->seqno, seqno)) 966 if (SEQNO_EQ ((*i)->seqno, seqno))
870 { 967 {
871 // already seen that request: simply reply with the cached reply 968 // already seen that request: simply reply with the cached reply
872 dns_rcv *r = *i; 969 dns_rcv *r = *i;
973 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 1070 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
974 pkt [offs++] = 0; pkt [offs++] = 0; 1071 pkt [offs++] = 0; pkt [offs++] = 0;
975 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 1072 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
976 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 1073 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
977 1074
978 slog (L_INFO, _("DNS: client %d connects"), client);
979
980 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 1075 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
981 pkt [offs++] = CMD_IP_REJ; 1076 pkt [offs++] = CMD_IP_REJ;
982 1077
983 if (0 < client && client <= conns.size ()) 1078 if (0 < client && client <= conns.size ())
984 { 1079 {
985 connection *c = conns [client - 1]; 1080 connection *c = conns [client - 1];
986 1081
987 if (cfg.valid ()) 1082 if (cfg.valid ())
988 { 1083 {
989 pkt [offs - 1] = CMD_IP_SYN; 1084 slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc);
1085
1086 // check for any encoding mismatches - hints at a case problem
1087 char qname2 [MAX_ENC_LEN];
1088 cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg));
990 1089
991 delete c->dns; 1090 delete c->dns;
1091
1092 pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg)))
1093 ? CMD_IP_CSE : CMD_IP_SYN;
1094
992 c->dns = new dns_connection (c); 1095 c->dns = new dns_connection (c);
993 c->dns->cfg = cfg; 1096 c->dns->cfg = cfg;
1097 c->dns->set_cfg ();
994 } 1098 }
995 } 1099 }
996 } 1100 }
997 } 1101 }
998 1102
1032#if 0 1136#if 0
1033 dns->send_interval *= 0.999; 1137 dns->send_interval *= 0.999;
1034#endif 1138#endif
1035 // the latency surely puts an upper bound on 1139 // the latency surely puts an upper bound on
1036 // the minimum send interval 1140 // the minimum send interval
1037 double latency = ev::ev_now () - (*i)->sent; 1141 double latency = ev_now () - (*i)->sent;
1038 1142
1039 if (latency < dns->min_latency) 1143 if (latency < dns->min_latency)
1040 dns->min_latency = latency; 1144 dns->min_latency = latency;
1041 1145
1042 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) 1146 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1069 ttl |= pkt [offs++] << 16; 1173 ttl |= pkt [offs++] << 16;
1070 ttl |= pkt [offs++] << 8; 1174 ttl |= pkt [offs++] << 8;
1071 ttl |= pkt [offs++]; 1175 ttl |= pkt [offs++];
1072 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; 1176 u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++];
1073 1177
1074 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT) 1178 if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype)
1075 { 1179 {
1076 if (rdlen <= MAXSIZE - offs) 1180 if (rdlen <= MAXSIZE - offs)
1077 { 1181 {
1078 // decode bytes, finally 1182 // decode bytes, finally
1079 1183
1105 { 1209 {
1106 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); 1210 slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1107 1211
1108 if (ip [3] == CMD_IP_RST) 1212 if (ip [3] == CMD_IP_RST)
1109 { 1213 {
1110 slog (L_DEBUG, _("DNS: got tunnel RST request")); 1214 slog (L_DEBUG, _("DNS: got tunnel RST request."));
1111 1215
1112 delete dns; c->dns = 0; 1216 dns->reset ();
1113
1114 return; 1217 return;
1115 } 1218 }
1116 else if (ip [3] == CMD_IP_SYN) 1219 else if (ip [3] == CMD_IP_SYN)
1117 { 1220 {
1118 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); 1221 slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1119 dns->established = true; 1222 dns->established = true;
1120 } 1223 }
1224 else if (ip [3] == CMD_IP_CSE)
1225 {
1226 if (conf.dns_case_preserving)
1227 {
1228 slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol."));
1229 conf.dns_case_preserving = false;
1230 dns->reset ();
1231 return;
1232 }
1233 else
1234 {
1235 slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us."));
1236 dns->established = true;
1237 }
1238 }
1121 else if (ip [3] == CMD_IP_REJ) 1239 else if (ip [3] == CMD_IP_REJ)
1122 { 1240 {
1123 slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); 1241 slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us."));
1124 abort (); 1242 dns->tw.start (60.);
1125 } 1243 }
1126 else 1244 else
1245 {
1127 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); 1246 slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1247 dns->tw.start (60.);
1248 }
1128 } 1249 }
1129 else 1250 else
1130 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), 1251 slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1131 ip [0], ip [1], ip [2], ip [3]); 1252 ip [0], ip [1], ip [2], ip [3]);
1132 1253
1194 1315
1195 if (!c->dns) 1316 if (!c->dns)
1196 c->dns = new dns_connection (c); 1317 c->dns = new dns_connection (c);
1197 1318
1198 if (c->dns->snddq.put (pkt)) 1319 if (c->dns->snddq.put (pkt))
1320 {
1321 min_it (c->dns->poll_interval, 0.25);
1199 c->dns->tw (); 1322 c->dns->tw ();
1323 }
1200 1324
1201 // always return true even if the buffer overflows 1325 // always return true even if the buffer overflows
1202 return true; 1326 return true;
1203} 1327}
1204
1205void
1206connection::dnsv4_reset_connection ()
1207{
1208 //delete dns; dns = 0; //TODO
1209}
1210
1211#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1212 1328
1213void 1329void
1214dns_connection::time_cb (ev::timer &w, int revents) 1330dns_connection::time_cb (ev::timer &w, int revents)
1215{ 1331{
1216 // servers have to be polled 1332 // servers have to be polled
1217 if (THISNODE->dns_port) 1333 if (THISNODE->dns_port)
1218 return; 1334 return;
1219 1335
1220 // check for timeouts and (re)transmit 1336 // check for timeouts and (re)transmit
1221 tstamp next = ev::now () + poll_interval; 1337 tstamp next = 86400 * 365;
1222 dns_snd *send = 0; 1338 dns_snd *send = 0;
1223 1339
1224 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1340 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1225 i != vpn->dns_sndpq.end (); 1341 i != vpn->dns_sndpq.end ();
1226 ++i) 1342 ++i)
1227 { 1343 {
1228 dns_snd *r = *i; 1344 dns_snd *r = *i;
1229 1345
1230 if (r->timeout <= ev::ev_now ()) 1346 if (r->timeout <= ev_now ())
1231 { 1347 {
1232 if (!send) 1348 if (!send)
1233 { 1349 {
1234 send = r; 1350 send = r;
1235 1351
1236 r->retry++; 1352 r->retry++;
1237 r->timeout = ev::ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); 1353 r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor;
1238 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev::ev_now ());//D 1354 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
1239 1355
1240 // the following code changes the query section a bit, forcing 1356 // the following code changes the query section a bit, forcing
1241 // the forwarder to generate a new request 1357 // the forwarder to generate a new request
1242 if (r->stdhdr) 1358 if (r->stdhdr)
1243 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1359 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1244 } 1360 }
1245 } 1361 }
1246 else 1362 else
1247 NEXT (r->timeout); 1363 min_it (next, r->timeout - ev_now ());
1248 } 1364 }
1249 1365
1250 if (!send) 1366 if (!send)
1251 { 1367 {
1252 // generate a new packet, if wise 1368 // generate a new packet, if wise
1256 if (vpn->dns_sndpq.empty ()) 1372 if (vpn->dns_sndpq.empty ())
1257 { 1373 {
1258 send = new dns_snd (this); 1374 send = new dns_snd (this);
1259 1375
1260 cfg.reset (THISNODE->id); 1376 cfg.reset (THISNODE->id);
1377 set_cfg ();
1261 send->gen_syn_req (); 1378 send->gen_syn_req ();
1262 } 1379 }
1263 } 1380 }
1264 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding 1381 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1265 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1382 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1266 { 1383 {
1267 if (last_sent + send_interval <= ev::ev_now ()) 1384 if (last_sent + send_interval <= ev_now ())
1268 { 1385 {
1269 //printf ("sending data request etc.\n"); //D 1386 //printf ("sending data request etc.\n"); //D
1270 if (!snddq.empty () || last_received + 1. > ev::ev_now ()) 1387 if (!snddq.empty ())
1271 {
1272 poll_interval = send_interval; 1388 min_it (next, send_interval);
1273 NEXT (ev::ev_now () + send_interval);
1274 }
1275 1389
1276 send = new dns_snd (this); 1390 send = new dns_snd (this);
1277 send->gen_stream_req (sndseq, snddq); 1391 send->gen_stream_req (sndseq, snddq);
1278 send->timeout = ev::ev_now () + min_latency * conf.dns_timeout_factor; 1392 send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
1279 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev::ev_now (), min_latency, conf.dns_timeout_factor);//D 1393 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1280 1394
1281 sndseq = (sndseq + 1) & SEQNO_MASK; 1395 sndseq = (sndseq + 1) & SEQNO_MASK;
1282 } 1396 }
1283 else 1397 else
1284 NEXT (last_sent + send_interval); 1398 min_it (next, last_sent + send_interval - ev_now ());
1285 } 1399 }
1286 1400
1287 if (send) 1401 if (send)
1288 vpn->dns_sndpq.push_back (send); 1402 vpn->dns_sndpq.push_back (send);
1289 } 1403 }
1290 1404
1291 if (send) 1405 if (send)
1292 { 1406 {
1293 last_sent = ev::ev_now (); 1407 last_sent = ev_now ();
1294 sendto (vpn->dnsv4_fd, 1408 sendto (vpn->dnsv4_fd,
1295 send->pkt->at (0), send->pkt->len, 0, 1409 send->pkt->at (0), send->pkt->len, 0,
1296 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1410 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1297 } 1411 }
1298 1412
1413 min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ());
1414
1299 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1415 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1300 poll_interval, send_interval, next - ev::ev_now (), 1416 poll_interval, send_interval, next - ev_now (),
1301 vpn->dns_sndpq.size (), snddq.size (), 1417 vpn->dns_sndpq.size (), snddq.size (),
1302 rcvpq.size ()); 1418 rcvpq.size ());
1303 1419
1304 // TODO: no idea when this happens, but when next < ev::ev_now (), we have a problem 1420 w.start (next);
1305 // doesn't seem to happen anymore
1306 if (next < ev::ev_now () + 0.001)
1307 next = ev::ev_now () + 0.1;
1308
1309 w.start (next - ev::ev_now ());
1310} 1421}
1311 1422
1312#endif 1423#endif
1313 1424

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