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) 2003-2008 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. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
19 | |
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20 | Additional permission under GNU GPL version 3 section 7 |
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21 | |
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22 | If you modify this Program, or any covered work, by linking or |
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23 | combining it with the OpenSSL project's OpenSSL library (or a modified |
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24 | version of that library), containing parts covered by the terms of the |
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25 | OpenSSL or SSLeay licenses, the licensors of this Program grant you |
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26 | additional permission to convey the resulting work. Corresponding |
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27 | Source for a non-source form of such a combination shall include the |
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28 | source code for the parts of OpenSSL used as well as that of the |
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29 | covered work. |
20 | */ |
30 | */ |
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31 | |
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32 | // TODO: EDNS0 option to increase dns mtu? |
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33 | // TODO: re-write dns packet parsing/creation using a safe mem-buffer |
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34 | // to ensure no buffer overflows or similar problems. |
21 | |
35 | |
22 | #include "config.h" |
36 | #include "config.h" |
23 | |
37 | |
24 | #if ENABLE_DNS |
38 | #if ENABLE_DNS |
25 | |
39 | |
26 | // dns processing is EXTREMELY ugly. For obvious(?) reasons. |
40 | // dns processing is EXTREMELY ugly. For obvious(?) reasons. |
27 | // it's a hack, use only in emergency situations please. |
41 | // it's a hack, use only in emergency situations please. |
28 | |
42 | |
29 | #include <cstring> |
43 | #include <cstring> |
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44 | #include <cassert> |
30 | |
45 | |
31 | #include <sys/types.h> |
46 | #include <sys/types.h> |
32 | #include <sys/socket.h> |
47 | #include <sys/socket.h> |
33 | #include <sys/wait.h> |
48 | #include <sys/wait.h> |
34 | #include <sys/uio.h> |
49 | #include <sys/uio.h> |
… | |
… | |
37 | #include <unistd.h> |
52 | #include <unistd.h> |
38 | #include <fcntl.h> |
53 | #include <fcntl.h> |
39 | |
54 | |
40 | #include <map> |
55 | #include <map> |
41 | |
56 | |
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57 | #include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */ |
42 | #include <gmp.h> |
58 | #include <gmp.h> |
43 | |
59 | |
44 | #include "netcompat.h" |
60 | #include "netcompat.h" |
45 | |
61 | |
46 | #include "vpn.h" |
62 | #include "vpn.h" |
47 | |
63 | |
48 | #define MIN_POLL_INTERVAL .02 // how often to poll minimally when the server is having data |
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49 | #define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data |
64 | #define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data |
50 | #define ACTIVITY_INTERVAL 5. |
65 | #define ACTIVITY_INTERVAL 5. |
51 | |
66 | |
52 | #define INITIAL_TIMEOUT 1. |
67 | #define INITIAL_TIMEOUT 0.1 // retry timeouts |
53 | #define INITIAL_SYN_TIMEOUT 2. |
68 | #define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn |
54 | |
69 | |
55 | #define MIN_SEND_INTERVAL 0.01 |
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56 | #define MAX_SEND_INTERVAL 0.5 // optimistic? |
70 | #define MAX_SEND_INTERVAL 2. // optimistic? |
57 | |
71 | |
58 | #define MAX_OUTSTANDING 40 // max. outstanding requests |
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59 | #define MAX_WINDOW 100 // max. for MAX_OUTSTANDING |
72 | #define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog |
60 | #define MAX_BACKLOG (100*1024) // size of protocol backlog, must be > MAXSIZE |
73 | #define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE |
61 | |
74 | |
62 | #define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well |
75 | #define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well |
63 | // 240 leaves about 4 bytes of server reply data |
76 | // 240 leaves about 4 bytes of server reply data |
64 | // every two request byte sless give room for one reply byte |
77 | // every request byte less give room for two reply bytes |
65 | |
78 | |
66 | #define SEQNO_MASK 0xffff |
79 | #define SEQNO_MASK 0x3fff |
67 | #define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) |
80 | #define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) |
68 | |
81 | |
69 | #define MAX_LBL_SIZE 63 |
82 | #define MAX_LBL_SIZE 63 |
70 | #define MAX_PKT_SIZE 512 |
83 | #define MAX_PKT_SIZE 512 |
71 | |
84 | |
… | |
… | |
264 | static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); |
277 | static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); |
265 | |
278 | |
266 | ///////////////////////////////////////////////////////////////////////////// |
279 | ///////////////////////////////////////////////////////////////////////////// |
267 | |
280 | |
268 | #define HDRSIZE 6 |
281 | #define HDRSIZE 6 |
269 | |
282 | |
270 | inline void encode_header (char *data, int clientid, int seqno) |
283 | inline void encode_header (char *data, int clientid, int seqno, int retry = 0) |
271 | { |
284 | { |
272 | u8 hdr[3] = { clientid, seqno >> 8, seqno }; |
285 | seqno &= SEQNO_MASK; |
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286 | |
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287 | u8 hdr[3] = { |
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288 | clientid, |
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289 | (seqno >> 8) | (retry << 6), |
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290 | seqno, |
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291 | }; |
273 | |
292 | |
274 | assert (clientid < 256); |
293 | assert (clientid < 256); |
275 | |
294 | |
276 | cdc26.encode (data, hdr, 3); |
295 | cdc26.encode (data, hdr, 3); |
277 | } |
296 | } |
… | |
… | |
281 | u8 hdr[3]; |
300 | u8 hdr[3]; |
282 | |
301 | |
283 | cdc26.decode (hdr, data, HDRSIZE); |
302 | cdc26.decode (hdr, data, HDRSIZE); |
284 | |
303 | |
285 | clientid = hdr[0]; |
304 | clientid = hdr[0]; |
286 | seqno = (hdr[1] << 8) | hdr[2]; |
305 | seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; |
287 | } |
306 | } |
288 | |
307 | |
289 | ///////////////////////////////////////////////////////////////////////////// |
308 | ///////////////////////////////////////////////////////////////////////////// |
290 | |
309 | |
291 | struct byte_stream |
310 | struct byte_stream |
… | |
… | |
320 | } |
339 | } |
321 | |
340 | |
322 | void byte_stream::remove (int count) |
341 | void byte_stream::remove (int count) |
323 | { |
342 | { |
324 | if (count > fill) |
343 | if (count > fill) |
325 | abort (); |
344 | assert (count <= fill); |
326 | |
345 | |
327 | memmove (data, data + count, fill -= count); |
346 | memmove (data, data + count, fill -= count); |
328 | } |
347 | } |
329 | |
348 | |
330 | bool byte_stream::put (u8 *data, unsigned int datalen) |
349 | bool byte_stream::put (u8 *data, unsigned int datalen) |
… | |
… | |
350 | return true; |
369 | return true; |
351 | } |
370 | } |
352 | |
371 | |
353 | vpn_packet *byte_stream::get () |
372 | vpn_packet *byte_stream::get () |
354 | { |
373 | { |
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374 | unsigned int len; |
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375 | |
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376 | for (;;) |
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377 | { |
355 | unsigned int len = (data [0] << 8) | data [1]; |
378 | len = (data [0] << 8) | data [1]; |
356 | |
379 | |
357 | if (len > MAXSIZE && fill >= 2) |
380 | if (len <= MAXSIZE || fill < 2) |
358 | abort (); // TODO handle this gracefully, connection reset |
381 | break; |
359 | |
382 | |
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383 | // TODO: handle this better than skipping, e.g. by reset |
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384 | slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte...")); |
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385 | remove (1); |
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386 | } |
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387 | |
360 | if (fill < len + 2) |
388 | if (fill < len + 2) |
361 | return 0; |
389 | return 0; |
362 | |
390 | |
363 | vpn_packet *pkt = new vpn_packet; |
391 | vpn_packet *pkt = new vpn_packet; |
364 | |
392 | |
… | |
… | |
393 | struct dns_cfg |
421 | struct dns_cfg |
394 | { |
422 | { |
395 | static int next_uid; |
423 | static int next_uid; |
396 | |
424 | |
397 | u8 id1, id2, id3, id4; |
425 | u8 id1, id2, id3, id4; |
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426 | |
398 | u8 version; |
427 | u8 version; |
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428 | u8 flags; |
399 | u8 rrtype; |
429 | u8 rrtype; |
400 | u8 flags; |
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401 | u8 def_ttl; |
430 | u8 def_ttl; |
402 | u8 rcv_cdc; |
431 | |
403 | u8 snd_cdc; |
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404 | u16 max_size; |
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405 | u16 client; |
432 | u16 client; |
406 | u16 uid; // to make request unique |
433 | u16 uid; // to make request unique |
407 | |
434 | |
408 | u8 reserved[8]; |
435 | u16 max_size; |
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436 | u8 seq_cdc; |
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437 | u8 req_cdc; |
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438 | |
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439 | u8 rep_cdc; |
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440 | u8 delay; // time in 0.01s units that the server may delay replying packets |
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441 | u8 r3, r4; |
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442 | |
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443 | u8 r5, r6, r7, r8; |
409 | |
444 | |
410 | void reset (int clientid); |
445 | void reset (int clientid); |
411 | bool valid (); |
446 | bool valid (); |
412 | }; |
447 | }; |
413 | |
448 | |
… | |
… | |
423 | version = 1; |
458 | version = 1; |
424 | |
459 | |
425 | rrtype = RR_TYPE_TXT; |
460 | rrtype = RR_TYPE_TXT; |
426 | flags = 0; |
461 | flags = 0; |
427 | def_ttl = 0; |
462 | def_ttl = 0; |
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463 | seq_cdc = 26; |
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464 | req_cdc = 62; |
428 | rcv_cdc = 0; |
465 | rep_cdc = 0; |
429 | snd_cdc = 62; |
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430 | max_size = ntohs (MAX_PKT_SIZE); |
466 | max_size = htons (MAX_PKT_SIZE); |
431 | client = ntohs (clientid); |
467 | client = htons (clientid); |
432 | uid = next_uid++; |
468 | uid = next_uid++; |
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469 | delay = 0; |
433 | |
470 | |
434 | memset (reserved, 0, 8); |
471 | r3 = r4 = 0; |
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472 | r4 = r5 = r6 = r7 = 0; |
435 | } |
473 | } |
436 | |
474 | |
437 | bool dns_cfg::valid () |
475 | bool dns_cfg::valid () |
438 | { |
476 | { |
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477 | // although the protocol itself allows for some configurability, |
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478 | // only the following encoding/decoding settings are implemented. |
439 | return id1 == 'G' |
479 | return id1 == 'G' |
440 | && id2 == 'V' |
480 | && id2 == 'V' |
441 | && id3 == 'P' |
481 | && id3 == 'P' |
442 | && id4 == 'E' |
482 | && id4 == 'E' |
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483 | && seq_cdc == 26 |
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484 | && req_cdc == 62 |
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485 | && rep_cdc == 0 |
443 | && version == 1 |
486 | && version == 1; |
444 | && flags == 0 |
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445 | && rcv_cdc == 0 |
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446 | && snd_cdc == 62 |
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447 | && max_size == ntohs (MAX_PKT_SIZE); |
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448 | } |
487 | } |
449 | |
488 | |
450 | struct dns_packet : net_packet |
489 | struct dns_packet : net_packet |
451 | { |
490 | { |
452 | u16 id; |
491 | u16 id; |
453 | u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 |
492 | u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 |
454 | u16 qdcount, ancount, nscount, arcount; |
493 | u16 qdcount, ancount, nscount, arcount; |
455 | |
494 | |
456 | u8 data[MAXSIZE - 6 * 2]; |
495 | u8 data [MAXSIZE - 6 * 2]; |
457 | |
496 | |
458 | int decode_label (char *data, int size, int &offs); |
497 | int decode_label (char *data, int size, int &offs); |
459 | }; |
498 | }; |
460 | |
499 | |
461 | int dns_packet::decode_label (char *data, int size, int &offs) |
500 | int dns_packet::decode_label (char *data, int size, int &offs) |
… | |
… | |
492 | return data - orig; |
531 | return data - orig; |
493 | } |
532 | } |
494 | |
533 | |
495 | ///////////////////////////////////////////////////////////////////////////// |
534 | ///////////////////////////////////////////////////////////////////////////// |
496 | |
535 | |
497 | struct dns_snd |
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498 | { |
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499 | dns_packet *pkt; |
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500 | tstamp timeout, sent; |
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501 | int retry; |
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502 | struct dns_connection *dns; |
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503 | int seqno; |
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504 | |
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505 | void gen_stream_req (int seqno, byte_stream &stream); |
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506 | void gen_syn_req (const dns_cfg &cfg); |
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507 | |
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508 | dns_snd (dns_connection *dns); |
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509 | ~dns_snd (); |
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510 | }; |
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511 | |
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512 | static u16 dns_id = 12098; // TODO: should be per-vpn |
536 | static u16 dns_id = 0; // TODO: should be per-vpn |
513 | |
537 | |
514 | static u16 next_id () |
538 | static u16 next_id () |
515 | { |
539 | { |
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540 | if (!dns_id) |
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541 | dns_id = time (0); |
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542 | |
516 | // the simplest lsfr with periodicity 65535 i could find |
543 | // the simplest lsfr with periodicity 65535 i could find |
517 | dns_id = (dns_id << 1) |
544 | dns_id = (dns_id << 1) |
518 | | (((dns_id >> 1) |
545 | | (((dns_id >> 1) |
519 | ^ (dns_id >> 2) |
546 | ^ (dns_id >> 2) |
520 | ^ (dns_id >> 4) |
547 | ^ (dns_id >> 4) |
521 | ^ (dns_id >> 15)) & 1); |
548 | ^ (dns_id >> 15)) & 1); |
522 | |
549 | |
523 | return dns_id; |
550 | return dns_id; |
524 | } |
551 | } |
525 | |
552 | |
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553 | struct dns_rcv; |
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554 | struct dns_snd; |
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555 | |
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556 | struct dns_connection |
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557 | { |
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558 | connection *c; |
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559 | struct vpn *vpn; |
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560 | |
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561 | dns_cfg cfg; |
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562 | |
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563 | bool established; |
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564 | |
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565 | tstamp last_received; |
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566 | tstamp last_sent; |
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567 | double min_latency; |
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568 | double poll_interval, send_interval; |
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569 | |
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570 | vector<dns_rcv *> rcvpq; |
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571 | |
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572 | byte_stream rcvdq; int rcvseq; int repseq; |
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573 | byte_stream snddq; int sndseq; |
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574 | |
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575 | inline void time_cb (ev::timer &w, int revents); ev::timer tw; |
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576 | void receive_rep (dns_rcv *r); |
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577 | |
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578 | dns_connection (connection *c); |
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579 | ~dns_connection (); |
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580 | }; |
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581 | |
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582 | struct dns_snd |
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583 | { |
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584 | dns_packet *pkt; |
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585 | tstamp timeout, sent; |
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586 | int retry; |
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587 | struct dns_connection *dns; |
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588 | int seqno; |
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589 | bool stdhdr; |
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590 | |
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591 | void gen_stream_req (int seqno, byte_stream &stream); |
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592 | void gen_syn_req (); |
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593 | |
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594 | dns_snd (dns_connection *dns); |
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595 | ~dns_snd (); |
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596 | }; |
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597 | |
526 | dns_snd::dns_snd (dns_connection *dns) |
598 | dns_snd::dns_snd (dns_connection *dns) |
527 | : dns (dns) |
599 | : dns (dns) |
528 | { |
600 | { |
529 | timeout = 0; |
601 | timeout = 0; |
530 | retry = 0; |
602 | retry = 0; |
531 | seqno = 0; |
603 | seqno = 0; |
532 | sent = NOW; |
604 | sent = ev_now (); |
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605 | stdhdr = false; |
533 | |
606 | |
534 | pkt = new dns_packet; |
607 | pkt = new dns_packet; |
535 | |
608 | |
536 | pkt->id = next_id (); |
609 | pkt->id = next_id (); |
537 | } |
610 | } |
… | |
… | |
564 | } |
637 | } |
565 | } |
638 | } |
566 | |
639 | |
567 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
640 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
568 | { |
641 | { |
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642 | stdhdr = true; |
569 | this->seqno = seqno; |
643 | this->seqno = seqno; |
570 | |
644 | |
571 | timeout = NOW + INITIAL_TIMEOUT; |
645 | timeout = ev_now () + INITIAL_TIMEOUT; |
572 | |
646 | |
573 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
647 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
574 | pkt->qdcount = htons (1); |
648 | pkt->qdcount = htons (1); |
575 | |
649 | |
576 | int offs = 6*2; |
650 | int offs = 6*2; |
577 | int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); |
651 | int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2); |
578 | // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, |
652 | // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, |
579 | // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra |
653 | // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra |
580 | |
654 | |
581 | char enc[256], *encp = enc; |
655 | char enc[256], *encp = enc; |
582 | encode_header (enc, THISNODE->id, seqno); |
656 | encode_header (enc, THISNODE->id, seqno); |
… | |
… | |
600 | encp += lbllen; |
674 | encp += lbllen; |
601 | |
675 | |
602 | enclen -= lbllen; |
676 | enclen -= lbllen; |
603 | } |
677 | } |
604 | |
678 | |
605 | append_domain (*pkt, offs, THISNODE->domain); |
679 | append_domain (*pkt, offs, dns->c->conf->domain); |
606 | |
680 | |
607 | (*pkt)[offs++] = 0; |
681 | (*pkt)[offs++] = 0; |
608 | (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; |
682 | (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; |
609 | (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
683 | (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
610 | |
684 | |
611 | pkt->len = offs; |
685 | pkt->len = offs; |
612 | } |
686 | } |
613 | |
687 | |
614 | void dns_snd::gen_syn_req (const dns_cfg &cfg) |
688 | void dns_snd::gen_syn_req () |
615 | { |
689 | { |
616 | timeout = NOW + INITIAL_SYN_TIMEOUT; |
690 | timeout = ev_now () + INITIAL_SYN_TIMEOUT; |
617 | |
691 | |
618 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
692 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
619 | pkt->qdcount = htons (1); |
693 | pkt->qdcount = htons (1); |
620 | |
694 | |
621 | int offs = 6*2; |
695 | int offs = 6 * 2; |
622 | |
696 | |
623 | int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); |
697 | int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg)); |
624 | |
698 | |
625 | assert (elen <= MAX_LBL_SIZE); |
699 | assert (elen <= MAX_LBL_SIZE); |
626 | |
700 | |
627 | (*pkt)[offs] = elen; |
701 | (*pkt)[offs] = elen; |
628 | offs += elen + 1; |
702 | offs += elen + 1; |
629 | append_domain (*pkt, offs, THISNODE->domain); |
703 | append_domain (*pkt, offs, dns->c->conf->domain); |
630 | |
704 | |
631 | (*pkt)[offs++] = 0; |
705 | (*pkt)[offs++] = 0; |
632 | (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; |
706 | (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; |
633 | (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
707 | (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
634 | |
708 | |
… | |
… | |
657 | delete pkt; |
731 | delete pkt; |
658 | } |
732 | } |
659 | |
733 | |
660 | ///////////////////////////////////////////////////////////////////////////// |
734 | ///////////////////////////////////////////////////////////////////////////// |
661 | |
735 | |
662 | struct dns_connection |
|
|
663 | { |
|
|
664 | connection *c; |
|
|
665 | struct vpn *vpn; |
|
|
666 | |
|
|
667 | dns_cfg cfg; |
|
|
668 | |
|
|
669 | bool established; |
|
|
670 | |
|
|
671 | tstamp last_received; |
|
|
672 | tstamp last_sent; |
|
|
673 | double poll_interval, send_interval; |
|
|
674 | |
|
|
675 | vector<dns_rcv *> rcvpq; |
|
|
676 | |
|
|
677 | byte_stream rcvdq; int rcvseq; |
|
|
678 | byte_stream snddq; int sndseq; |
|
|
679 | |
|
|
680 | void time_cb (time_watcher &w); time_watcher tw; |
|
|
681 | void receive_rep (dns_rcv *r); |
|
|
682 | |
|
|
683 | dns_connection (connection *c); |
|
|
684 | ~dns_connection (); |
|
|
685 | }; |
|
|
686 | |
|
|
687 | dns_connection::dns_connection (connection *c) |
736 | dns_connection::dns_connection (connection *c) |
688 | : c (c) |
737 | : c (c) |
689 | , rcvdq (MAX_BACKLOG * 2) |
738 | , rcvdq (MAX_BACKLOG * 2) |
690 | , snddq (MAX_BACKLOG * 2) |
739 | , snddq (MAX_BACKLOG) |
691 | , tw (this, &dns_connection::time_cb) |
|
|
692 | { |
740 | { |
|
|
741 | tw.set<dns_connection, &dns_connection::time_cb> (this); |
|
|
742 | |
693 | vpn = c->vpn; |
743 | vpn = c->vpn; |
694 | |
744 | |
695 | established = false; |
745 | established = false; |
696 | |
746 | |
697 | rcvseq = sndseq = 0; |
747 | rcvseq = repseq = sndseq = 0; |
698 | |
748 | |
699 | last_sent = last_received = 0; |
749 | last_sent = last_received = 0; |
700 | poll_interval = MIN_POLL_INTERVAL; |
750 | poll_interval = 0.5; // starting here |
701 | send_interval = 0.2; // starting rate |
751 | send_interval = 0.5; // starting rate |
|
|
752 | min_latency = INITIAL_TIMEOUT; |
702 | } |
753 | } |
703 | |
754 | |
704 | dns_connection::~dns_connection () |
755 | dns_connection::~dns_connection () |
705 | { |
756 | { |
706 | for (vector<dns_rcv *>::iterator i = rcvpq.begin (); |
757 | for (vector<dns_rcv *>::iterator i = rcvpq.begin (); |
… | |
… | |
711 | |
762 | |
712 | void dns_connection::receive_rep (dns_rcv *r) |
763 | void dns_connection::receive_rep (dns_rcv *r) |
713 | { |
764 | { |
714 | if (r->datalen) |
765 | if (r->datalen) |
715 | { |
766 | { |
716 | last_received = NOW; |
767 | last_received = ev_now (); |
717 | tw.trigger (); |
768 | tw (); |
718 | |
769 | |
719 | poll_interval = send_interval; |
770 | poll_interval = send_interval; |
720 | } |
771 | } |
721 | else |
772 | else |
722 | { |
773 | { |
723 | poll_interval *= 1.1; |
774 | poll_interval *= 1.5; |
|
|
775 | |
724 | if (poll_interval > MAX_POLL_INTERVAL) |
776 | if (poll_interval > MAX_POLL_INTERVAL) |
725 | poll_interval = MAX_POLL_INTERVAL; |
777 | poll_interval = MAX_POLL_INTERVAL; |
726 | } |
778 | } |
727 | |
779 | |
728 | rcvpq.push_back (r); |
780 | rcvpq.push_back (r); |
… | |
… | |
731 | |
783 | |
732 | // find next packet |
784 | // find next packet |
733 | for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
785 | for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
734 | if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
786 | if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
735 | { |
787 | { |
|
|
788 | //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D |
736 | // enter the packet into our input stream |
789 | // enter the packet into our input stream |
737 | r = *i; |
790 | r = *i; |
738 | |
791 | |
739 | // remove the oldest packet, look forward, as it's oldest first |
792 | // remove the oldest packet, look forward, as it's oldest first |
740 | for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
793 | for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
741 | if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
794 | if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
742 | { |
795 | { |
|
|
796 | //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D |
743 | delete *j; |
797 | delete *j; |
744 | rcvpq.erase (j); |
798 | rcvpq.erase (j); |
745 | break; |
799 | break; |
746 | } |
800 | } |
747 | |
801 | |
748 | rcvseq = (rcvseq + 1) & SEQNO_MASK; |
802 | rcvseq = (rcvseq + 1) & SEQNO_MASK; |
749 | |
803 | |
750 | if (!rcvdq.put (r->data, r->datalen)) |
804 | if (!rcvdq.put (r->data, r->datalen)) |
|
|
805 | { |
|
|
806 | slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); |
751 | abort (); // MUST never overflow, can be caused by data corruption, TODO |
807 | abort (); // MUST never overflow, can be caused by data corruption, TODO |
|
|
808 | } |
752 | |
809 | |
753 | while (vpn_packet *pkt = rcvdq.get ()) |
810 | while (vpn_packet *pkt = rcvdq.get ()) |
754 | { |
811 | { |
755 | sockinfo si; |
812 | sockinfo si; |
756 | si.host = 0; si.port = 0; si.prot = PROT_DNSv4; |
813 | si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; |
757 | |
814 | |
758 | vpn->recv_vpn_packet (pkt, si); |
815 | vpn->recv_vpn_packet (pkt, si); |
759 | |
816 | |
760 | delete pkt; |
817 | delete pkt; |
761 | } |
818 | } |
… | |
… | |
775 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
832 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
776 | |
833 | |
777 | if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) |
834 | if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) |
778 | && pkt.qdcount == htons (1)) |
835 | && pkt.qdcount == htons (1)) |
779 | { |
836 | { |
780 | char qname[MAXSIZE]; |
837 | char qname [MAXSIZE]; |
781 | int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); |
838 | int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); |
782 | |
839 | |
783 | u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; |
840 | u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; |
784 | u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; |
841 | u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; |
785 | |
842 | |
786 | pkt.qdcount = htons (1); |
843 | pkt.qdcount = htons (1); |
787 | pkt.ancount = 0; |
844 | pkt.ancount = 0; |
788 | pkt.nscount = 0; // should be self, as other nameservers reply like this |
845 | pkt.nscount = 0; // should be self, as other nameservers reply like this |
789 | pkt.arcount = 0; // a record for self, as other nameservers reply like this |
846 | pkt.arcount = 0; // a record for self, as other nameservers reply like this |
790 | |
847 | |
791 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_NXDOMAIN); |
848 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_SERVFAIL); |
792 | |
849 | |
793 | int dlen = strlen (THISNODE->domain); |
850 | int dlen = strlen (THISNODE->domain); |
794 | |
851 | |
795 | if (qclass == RR_CLASS_IN |
852 | if (qclass == RR_CLASS_IN |
796 | && qlen > dlen + 1 |
853 | && qlen > dlen + 1 |
797 | && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) |
854 | && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen)) |
798 | { |
855 | { |
799 | // now generate reply |
856 | // now generate reply |
800 | pkt.ancount = htons (1); // one answer RR |
857 | pkt.ancount = htons (1); // one answer RR |
801 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); |
858 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); |
802 | |
859 | |
… | |
… | |
824 | if (SEQNO_EQ ((*i)->seqno, seqno)) |
881 | if (SEQNO_EQ ((*i)->seqno, seqno)) |
825 | { |
882 | { |
826 | // already seen that request: simply reply with the cached reply |
883 | // already seen that request: simply reply with the cached reply |
827 | dns_rcv *r = *i; |
884 | dns_rcv *r = *i; |
828 | |
885 | |
829 | slog (L_DEBUG, "DUPLICATE %d\n", htons (r->pkt->id)); |
886 | slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno); |
|
|
887 | |
|
|
888 | // refresh header & id, as the retry count could have changed |
|
|
889 | memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE); |
|
|
890 | r->pkt->id = pkt.id; |
830 | |
891 | |
831 | memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); |
892 | memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); |
832 | pkt.id = r->pkt->id; |
893 | |
833 | goto duplicate_request; |
894 | goto duplicate_request; |
834 | } |
895 | } |
835 | |
896 | |
836 | // new packet, queue |
897 | // new packet, queue |
837 | rcv = new dns_rcv (seqno, data, datalen); |
898 | rcv = new dns_rcv (seqno, data, datalen); |
838 | dns->receive_rep (rcv); |
899 | dns->receive_rep (rcv); |
839 | } |
900 | } |
840 | |
901 | |
|
|
902 | { |
841 | pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section |
903 | pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section |
842 | |
904 | |
843 | int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; |
905 | int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; |
844 | pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type |
906 | pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type |
845 | pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
907 | pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
846 | pkt [offs++] = 0; pkt [offs++] = 0; |
908 | pkt [offs++] = 0; pkt [offs++] = 0; |
847 | pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL |
909 | pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL |
848 | |
910 | |
849 | int rdlen_offs = offs += 2; |
911 | int rdlen_offs = offs += 2; |
850 | |
912 | |
|
|
913 | if (dns) |
|
|
914 | { |
851 | int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; |
915 | int dlen = ntohs (dns->cfg.max_size) - offs; |
|
|
916 | |
852 | // bind doesn't compress well, so reduce further by one label length |
917 | // bind doesn't compress well, so reduce further by one label length |
853 | dlen -= qlen; |
918 | dlen -= qlen; |
854 | |
919 | |
855 | if (dns) |
920 | // only put data into in-order sequence packets, if |
856 | { |
921 | // we receive out-of-order packets we generate empty |
857 | while (dlen > 1 && !dns->snddq.empty ()) |
922 | // replies |
|
|
923 | //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D |
|
|
924 | if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW) |
858 | { |
925 | { |
|
|
926 | dns->repseq = seqno; |
|
|
927 | |
|
|
928 | while (dlen > 1 && !dns->snddq.empty ()) |
|
|
929 | { |
859 | int txtlen = dlen <= 255 ? dlen - 1 : 255; |
930 | int txtlen = dlen <= 255 ? dlen - 1 : 255; |
860 | |
931 | |
861 | if (txtlen > dns->snddq.size ()) |
932 | if (txtlen > dns->snddq.size ()) |
862 | txtlen = dns->snddq.size (); |
933 | txtlen = dns->snddq.size (); |
863 | |
934 | |
864 | pkt[offs++] = txtlen; |
935 | pkt[offs++] = txtlen; |
865 | memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); |
936 | memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); |
866 | offs += txtlen; |
937 | offs += txtlen; |
867 | dns->snddq.remove (txtlen); |
938 | dns->snddq.remove (txtlen); |
868 | |
939 | |
869 | dlen -= txtlen + 1; |
940 | dlen -= txtlen + 1; |
|
|
941 | } |
870 | } |
942 | } |
871 | |
943 | |
872 | // avoid empty TXT rdata |
944 | // avoid completely empty TXT rdata |
873 | if (offs == rdlen_offs) |
945 | if (offs == rdlen_offs) |
874 | pkt[offs++] = 0; |
946 | pkt[offs++] = 0; |
|
|
947 | |
|
|
948 | slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); |
875 | } |
949 | } |
876 | else |
950 | else |
877 | { |
951 | { |
878 | // send RST |
952 | // send RST |
879 | pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
953 | pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
880 | pkt [offs++] = CMD_IP_RST; |
954 | pkt [offs++] = CMD_IP_RST; |
881 | } |
955 | } |
882 | |
956 | |
883 | int rdlen = offs - rdlen_offs; |
957 | int rdlen = offs - rdlen_offs; |
884 | |
958 | |
885 | pkt [rdlen_offs - 2] = rdlen >> 8; |
959 | pkt [rdlen_offs - 2] = rdlen >> 8; |
886 | pkt [rdlen_offs - 1] = rdlen; |
960 | pkt [rdlen_offs - 1] = rdlen; |
887 | |
961 | |
888 | if (dns) |
962 | if (dns) |
889 | { |
963 | { |
890 | // now update dns_rcv copy |
964 | // now update dns_rcv copy |
891 | rcv->pkt->len = offs; |
965 | rcv->pkt->len = offs; |
892 | memcpy (rcv->pkt->at (0), pkt.at (0), offs); |
966 | memcpy (rcv->pkt->at (0), pkt.at (0), offs); |
893 | } |
967 | } |
|
|
968 | } |
894 | |
969 | |
895 | duplicate_request: ; |
970 | duplicate_request: ; |
896 | } |
971 | } |
897 | else |
972 | else |
898 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
973 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
… | |
… | |
910 | pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
985 | pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
911 | pkt [offs++] = 0; pkt [offs++] = 0; |
986 | pkt [offs++] = 0; pkt [offs++] = 0; |
912 | pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL |
987 | pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL |
913 | pkt [offs++] = 0; pkt [offs++] = 4; // rdlength |
988 | pkt [offs++] = 0; pkt [offs++] = 4; // rdlength |
914 | |
989 | |
915 | slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client); |
990 | slog (L_INFO, _("DNS: client %d connects"), client); |
916 | |
991 | |
917 | pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
992 | pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
918 | pkt [offs++] = CMD_IP_REJ; |
993 | pkt [offs++] = CMD_IP_REJ; |
919 | |
994 | |
920 | if (0 < client && client <= conns.size ()) |
995 | if (0 < client && client <= conns.size ()) |
… | |
… | |
954 | { |
1029 | { |
955 | dns_connection *dns = (*i)->dns; |
1030 | dns_connection *dns = (*i)->dns; |
956 | connection *c = dns->c; |
1031 | connection *c = dns->c; |
957 | int seqno = (*i)->seqno; |
1032 | int seqno = (*i)->seqno; |
958 | u8 data[MAXSIZE], *datap = data; |
1033 | u8 data[MAXSIZE], *datap = data; |
|
|
1034 | //printf ("rcv pkt %x\n", seqno);//D |
959 | |
1035 | |
960 | if ((*i)->retry) |
1036 | if ((*i)->retry) |
961 | { |
1037 | { |
962 | dns->send_interval *= 1.001; |
1038 | dns->send_interval *= 1.01; |
963 | if (dns->send_interval > MAX_SEND_INTERVAL) |
1039 | if (dns->send_interval > MAX_SEND_INTERVAL) |
964 | dns->send_interval = MAX_SEND_INTERVAL; |
1040 | dns->send_interval = MAX_SEND_INTERVAL; |
965 | } |
1041 | } |
966 | else |
1042 | else |
967 | { |
1043 | { |
968 | #if 1 |
1044 | #if 0 |
969 | dns->send_interval *= 0.9999; |
1045 | dns->send_interval *= 0.999; |
970 | #endif |
1046 | #endif |
971 | if (dns->send_interval < MIN_SEND_INTERVAL) |
|
|
972 | dns->send_interval = MIN_SEND_INTERVAL; |
|
|
973 | |
|
|
974 | // the latency surely puts an upper bound on |
1047 | // the latency surely puts an upper bound on |
975 | // the minimum send interval |
1048 | // the minimum send interval |
976 | double latency = NOW - (*i)->sent; |
1049 | double latency = ev_now () - (*i)->sent; |
977 | |
1050 | |
978 | if (dns->send_interval > latency) |
1051 | if (latency < dns->min_latency) |
979 | dns->send_interval = latency; |
1052 | dns->min_latency = latency; |
|
|
1053 | |
|
|
1054 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
|
|
1055 | dns->send_interval = dns->min_latency * conf.dns_overlap_factor; |
|
|
1056 | |
|
|
1057 | if (dns->send_interval < conf.dns_send_interval) |
|
|
1058 | dns->send_interval = conf.dns_send_interval; |
980 | } |
1059 | } |
981 | |
1060 | |
982 | delete *i; |
1061 | delete *i; |
983 | dns_sndpq.erase (i); |
1062 | dns_sndpq.erase (i); |
984 | |
1063 | |
… | |
… | |
1034 | |
1113 | |
1035 | if (ip [0] == CMD_IP_1 |
1114 | if (ip [0] == CMD_IP_1 |
1036 | && ip [1] == CMD_IP_2 |
1115 | && ip [1] == CMD_IP_2 |
1037 | && ip [2] == CMD_IP_3) |
1116 | && ip [2] == CMD_IP_3) |
1038 | { |
1117 | { |
1039 | slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]); |
1118 | slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); |
1040 | |
1119 | |
1041 | if (ip [3] == CMD_IP_RST) |
1120 | if (ip [3] == CMD_IP_RST) |
1042 | { |
1121 | { |
1043 | slog (L_DEBUG, _("got tunnel RST request")); |
1122 | slog (L_DEBUG, _("DNS: got tunnel RST request")); |
1044 | |
1123 | |
1045 | delete dns; c->dns = 0; |
1124 | delete dns; c->dns = 0; |
1046 | |
1125 | |
1047 | return; |
1126 | return; |
1048 | } |
1127 | } |
1049 | else if (ip [3] == CMD_IP_SYN) |
1128 | else if (ip [3] == CMD_IP_SYN) |
1050 | { |
1129 | { |
1051 | slog (L_DEBUG, _("got tunnel SYN reply, server likes us.")); |
1130 | slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); |
1052 | dns->established = true; |
1131 | dns->established = true; |
1053 | } |
1132 | } |
1054 | else if (ip [3] == CMD_IP_REJ) |
1133 | else if (ip [3] == CMD_IP_REJ) |
1055 | { |
1134 | { |
1056 | slog (L_DEBUG, _("got tunnel REJ reply, server does not like us, aborting.")); |
1135 | slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); |
1057 | abort (); |
1136 | abort (); |
1058 | } |
1137 | } |
1059 | else |
1138 | else |
1060 | slog (L_INFO, _("got unknown meta command %02x"), ip [3]); |
1139 | slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); |
1061 | } |
1140 | } |
1062 | else |
1141 | else |
1063 | slog (L_INFO, _("got spurious a record %d.%d.%d.%d"), |
1142 | slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), |
1064 | ip [0], ip [1], ip [2], ip [3]); |
1143 | ip [0], ip [1], ip [2], ip [3]); |
1065 | |
1144 | |
1066 | return; |
1145 | return; |
1067 | } |
1146 | } |
1068 | |
1147 | |
1069 | int client, rseqno; |
1148 | int client, rseqno; |
1070 | decode_header (qname, client, rseqno); |
1149 | decode_header (qname, client, rseqno); |
1071 | |
1150 | |
1072 | if (client != THISNODE->id) |
1151 | if (client != THISNODE->id) |
1073 | { |
1152 | { |
1074 | slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring")); |
1153 | slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring")); |
1075 | datap = 0; |
1154 | datap = 0; |
1076 | } |
1155 | } |
1077 | else if (rseqno != seqno) |
1156 | else if (rseqno != seqno) |
1078 | { |
1157 | { |
1079 | slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?")); |
1158 | slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?")); |
1080 | datap = 0; |
1159 | datap = 0; |
1081 | } |
1160 | } |
1082 | } |
1161 | } |
1083 | } |
1162 | } |
1084 | |
1163 | |
… | |
… | |
1089 | break; |
1168 | break; |
1090 | } |
1169 | } |
1091 | } |
1170 | } |
1092 | |
1171 | |
1093 | void |
1172 | void |
1094 | vpn::dnsv4_ev (io_watcher &w, short revents) |
1173 | vpn::dnsv4_ev (ev::io &w, int revents) |
1095 | { |
1174 | { |
1096 | if (revents & EVENT_READ) |
1175 | if (revents & EV_READ) |
1097 | { |
1176 | { |
1098 | dns_packet *pkt = new dns_packet; |
1177 | dns_packet *pkt = new dns_packet; |
1099 | struct sockaddr_in sa; |
1178 | struct sockaddr_in sa; |
1100 | socklen_t sa_len = sizeof (sa); |
1179 | socklen_t sa_len = sizeof (sa); |
1101 | |
1180 | |
1102 | pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); |
1181 | pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); |
1103 | |
1182 | |
1104 | if (pkt->len > 0) |
1183 | if (pkt->len > 0) |
1105 | { |
1184 | { |
1106 | if (THISNODE->dns_port) |
1185 | if (ntohs (pkt->flags) & FLAG_RESPONSE) |
|
|
1186 | dnsv4_client (*pkt); |
|
|
1187 | else |
1107 | { |
1188 | { |
1108 | dnsv4_server (*pkt); |
1189 | dnsv4_server (*pkt); |
1109 | sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); |
1190 | sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); |
1110 | } |
1191 | } |
1111 | else |
|
|
1112 | dnsv4_client (*pkt); |
|
|
1113 | |
1192 | |
1114 | delete pkt; |
1193 | delete pkt; |
1115 | } |
1194 | } |
1116 | } |
1195 | } |
1117 | } |
1196 | } |
1118 | |
1197 | |
1119 | bool |
1198 | bool |
1120 | connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
1199 | vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
1121 | { |
1200 | { |
|
|
1201 | int client = ntohl (si.host); |
|
|
1202 | |
|
|
1203 | assert (0 < client && client <= conns.size ()); |
|
|
1204 | |
|
|
1205 | connection *c = conns [client - 1]; |
|
|
1206 | |
1122 | if (!dns) |
1207 | if (!c->dns) |
1123 | dns = new dns_connection (this); |
1208 | c->dns = new dns_connection (c); |
1124 | |
1209 | |
1125 | if (!dns->snddq.put (pkt)) |
1210 | if (c->dns->snddq.put (pkt)) |
1126 | return false; |
1211 | c->dns->tw (); |
1127 | |
1212 | |
1128 | dns->tw.trigger (); |
1213 | // always return true even if the buffer overflows |
1129 | |
|
|
1130 | return true; |
1214 | return true; |
1131 | } |
1215 | } |
1132 | |
1216 | |
1133 | void |
1217 | void |
1134 | connection::dnsv4_reset_connection () |
1218 | connection::dnsv4_reset_connection () |
… | |
… | |
1137 | } |
1221 | } |
1138 | |
1222 | |
1139 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
1223 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
1140 | |
1224 | |
1141 | void |
1225 | void |
1142 | dns_connection::time_cb (time_watcher &w) |
1226 | dns_connection::time_cb (ev::timer &w, int revents) |
1143 | { |
1227 | { |
1144 | // servers have to be polled |
1228 | // servers have to be polled |
1145 | if (THISNODE->dns_port) |
1229 | if (THISNODE->dns_port) |
1146 | return; |
1230 | return; |
1147 | |
1231 | |
1148 | // check for timeouts and (re)transmit |
1232 | // check for timeouts and (re)transmit |
1149 | tstamp next = NOW + poll_interval; |
1233 | tstamp next = ev::now () + poll_interval; |
1150 | dns_snd *send = 0; |
1234 | dns_snd *send = 0; |
1151 | |
1235 | |
1152 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1236 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1153 | i != vpn->dns_sndpq.end (); |
1237 | i != vpn->dns_sndpq.end (); |
1154 | ++i) |
1238 | ++i) |
1155 | { |
1239 | { |
1156 | dns_snd *r = *i; |
1240 | dns_snd *r = *i; |
1157 | |
1241 | |
1158 | if (r->timeout <= NOW) |
1242 | if (r->timeout <= ev_now ()) |
1159 | { |
1243 | { |
1160 | if (!send) |
1244 | if (!send) |
1161 | { |
1245 | { |
1162 | send = r; |
1246 | send = r; |
1163 | |
1247 | |
1164 | r->retry++; |
1248 | r->retry++; |
1165 | r->timeout = NOW + r->retry; |
1249 | r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); |
|
|
1250 | //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D |
|
|
1251 | |
|
|
1252 | // the following code changes the query section a bit, forcing |
|
|
1253 | // the forwarder to generate a new request |
|
|
1254 | if (r->stdhdr) |
|
|
1255 | encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); |
1166 | } |
1256 | } |
1167 | } |
1257 | } |
1168 | else |
1258 | else |
1169 | NEXT (r->timeout); |
1259 | NEXT (r->timeout); |
1170 | } |
1260 | } |
1171 | |
1261 | |
1172 | if (last_sent + send_interval <= NOW) |
|
|
1173 | { |
|
|
1174 | if (!send) |
1262 | if (!send) |
|
|
1263 | { |
|
|
1264 | // generate a new packet, if wise |
|
|
1265 | |
|
|
1266 | if (!established) |
1175 | { |
1267 | { |
1176 | // generate a new packet, if wise |
|
|
1177 | |
|
|
1178 | if (!established) |
|
|
1179 | { |
|
|
1180 | if (vpn->dns_sndpq.empty ()) |
1268 | if (vpn->dns_sndpq.empty ()) |
1181 | { |
|
|
1182 | send = new dns_snd (this); |
|
|
1183 | |
|
|
1184 | cfg.reset (THISNODE->id); |
|
|
1185 | send->gen_syn_req (cfg); |
|
|
1186 | } |
|
|
1187 | } |
|
|
1188 | else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING) |
|
|
1189 | { |
1269 | { |
1190 | send = new dns_snd (this); |
1270 | send = new dns_snd (this); |
|
|
1271 | |
|
|
1272 | cfg.reset (THISNODE->id); |
|
|
1273 | send->gen_syn_req (); |
|
|
1274 | } |
|
|
1275 | } |
|
|
1276 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
|
|
1277 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
|
|
1278 | { |
|
|
1279 | if (last_sent + send_interval <= ev_now ()) |
|
|
1280 | { |
|
|
1281 | //printf ("sending data request etc.\n"); //D |
|
|
1282 | if (!snddq.empty () || last_received + 1. > ev_now ()) |
|
|
1283 | { |
|
|
1284 | poll_interval = send_interval; |
|
|
1285 | NEXT (ev_now () + send_interval); |
|
|
1286 | } |
|
|
1287 | |
|
|
1288 | send = new dns_snd (this); |
1191 | send->gen_stream_req (sndseq, snddq); |
1289 | send->gen_stream_req (sndseq, snddq); |
|
|
1290 | send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; |
|
|
1291 | //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D |
1192 | |
1292 | |
1193 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1293 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1194 | } |
1294 | } |
1195 | |
1295 | else |
1196 | if (send) |
1296 | NEXT (last_sent + send_interval); |
1197 | vpn->dns_sndpq.push_back (send); |
|
|
1198 | } |
1297 | } |
1199 | |
1298 | |
1200 | if (send) |
1299 | if (send) |
1201 | { |
1300 | vpn->dns_sndpq.push_back (send); |
1202 | last_sent = NOW; |
1301 | } |
|
|
1302 | |
|
|
1303 | if (send) |
|
|
1304 | { |
|
|
1305 | last_sent = ev_now (); |
1203 | sendto (vpn->dnsv4_fd, |
1306 | sendto (vpn->dnsv4_fd, |
1204 | send->pkt->at (0), send->pkt->len, 0, |
1307 | send->pkt->at (0), send->pkt->len, 0, |
1205 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1308 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1206 | } |
|
|
1207 | } |
1309 | } |
1208 | else |
|
|
1209 | NEXT (last_sent + send_interval); |
|
|
1210 | |
1310 | |
1211 | slog (L_NOISE, "pi %f si %f N %f (%d:%d)", |
1311 | slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", |
1212 | poll_interval, send_interval, next - NOW, |
1312 | poll_interval, send_interval, next - ev_now (), |
1213 | vpn->dns_sndpq.size (), snddq.size ()); |
1313 | vpn->dns_sndpq.size (), snddq.size (), |
|
|
1314 | rcvpq.size ()); |
1214 | |
1315 | |
1215 | // TODO: no idea when this happens, but when next < NOW, we have a problem |
1316 | // TODO: no idea when this happens, but when next < ev_now (), we have a problem |
|
|
1317 | // doesn't seem to happen anymore |
1216 | if (next < NOW + 0.0001) |
1318 | if (next < ev_now () + 0.001) |
1217 | next = NOW + 0.1; |
1319 | next = ev_now () + 0.1; |
1218 | |
1320 | |
1219 | w.start (next); |
1321 | w.start (next - ev_now ()); |
1220 | } |
1322 | } |
1221 | |
1323 | |
1222 | #endif |
1324 | #endif |
1223 | |
1325 | |