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 .2 // 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 (1./1000.) |
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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 400 // max. outstanding requests |
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59 | #define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING |
72 | #define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog |
60 | #define MAX_RATE 100 // requests/s |
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61 | #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 |
62 | |
74 | |
63 | #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 |
64 | // 240 leaves about 4 bytes of server reply data |
76 | // 240 leaves about 4 bytes of server reply data |
65 | // every two request byte sless give room for one reply byte |
77 | // every request byte less give room for two reply bytes |
66 | |
78 | |
67 | #define SEQNO_MASK 0xffff |
79 | #define SEQNO_MASK 0x3fff |
68 | #define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) |
80 | #define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) |
69 | |
81 | |
70 | #define MAX_LBL_SIZE 63 |
82 | #define MAX_LBL_SIZE 63 |
71 | #define MAX_PKT_SIZE 512 |
83 | #define MAX_PKT_SIZE 512 |
72 | |
84 | |
73 | #define RR_TYPE_A 1 |
85 | #define RR_TYPE_A 1 |
74 | #define RR_TYPE_NULL 10 |
86 | #define RR_TYPE_NULL 10 |
75 | #define RR_TYPE_TXT 16 |
87 | #define RR_TYPE_TXT 16 |
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88 | #define RR_TYPE_AAAA 28 |
76 | #define RR_TYPE_ANY 255 |
89 | #define RR_TYPE_ANY 255 |
77 | |
90 | |
78 | #define RR_CLASS_IN 1 |
91 | #define RR_CLASS_IN 1 |
79 | |
92 | |
80 | #define CMD_IP_1 207 |
93 | #define CMD_IP_1 207 |
… | |
… | |
265 | static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); |
278 | static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); |
266 | |
279 | |
267 | ///////////////////////////////////////////////////////////////////////////// |
280 | ///////////////////////////////////////////////////////////////////////////// |
268 | |
281 | |
269 | #define HDRSIZE 6 |
282 | #define HDRSIZE 6 |
270 | |
283 | |
271 | inline void encode_header (char *data, int clientid, int seqno) |
284 | inline void encode_header (char *data, int clientid, int seqno, int retry = 0) |
272 | { |
285 | { |
273 | u8 hdr[3] = { clientid, seqno >> 8, seqno }; |
286 | seqno &= SEQNO_MASK; |
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287 | |
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288 | u8 hdr[3] = { |
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289 | clientid, |
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290 | (seqno >> 8) | (retry << 6), |
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291 | seqno, |
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292 | }; |
274 | |
293 | |
275 | assert (clientid < 256); |
294 | assert (clientid < 256); |
276 | |
295 | |
277 | cdc26.encode (data, hdr, 3); |
296 | cdc26.encode (data, hdr, 3); |
278 | } |
297 | } |
… | |
… | |
282 | u8 hdr[3]; |
301 | u8 hdr[3]; |
283 | |
302 | |
284 | cdc26.decode (hdr, data, HDRSIZE); |
303 | cdc26.decode (hdr, data, HDRSIZE); |
285 | |
304 | |
286 | clientid = hdr[0]; |
305 | clientid = hdr[0]; |
287 | seqno = (hdr[1] << 8) | hdr[2]; |
306 | seqno = ((hdr[1] << 8) | hdr[2]) & SEQNO_MASK; |
288 | } |
307 | } |
289 | |
308 | |
290 | ///////////////////////////////////////////////////////////////////////////// |
309 | ///////////////////////////////////////////////////////////////////////////// |
291 | |
310 | |
292 | struct byte_stream |
311 | struct byte_stream |
… | |
… | |
321 | } |
340 | } |
322 | |
341 | |
323 | void byte_stream::remove (int count) |
342 | void byte_stream::remove (int count) |
324 | { |
343 | { |
325 | if (count > fill) |
344 | if (count > fill) |
326 | abort (); |
345 | assert (count <= fill); |
327 | |
346 | |
328 | memmove (data, data + count, fill -= count); |
347 | memmove (data, data + count, fill -= count); |
329 | } |
348 | } |
330 | |
349 | |
331 | bool byte_stream::put (u8 *data, unsigned int datalen) |
350 | bool byte_stream::put (u8 *data, unsigned int datalen) |
… | |
… | |
351 | return true; |
370 | return true; |
352 | } |
371 | } |
353 | |
372 | |
354 | vpn_packet *byte_stream::get () |
373 | vpn_packet *byte_stream::get () |
355 | { |
374 | { |
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375 | unsigned int len; |
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376 | |
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377 | for (;;) |
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378 | { |
356 | int len = (data [0] << 8) | data [1]; |
379 | len = (data [0] << 8) | data [1]; |
357 | |
380 | |
358 | if (len > MAXSIZE && fill >= 2) |
381 | if (len <= MAXSIZE || fill < 2) |
359 | abort (); // TODO handle this gracefully, connection reset |
382 | break; |
360 | |
383 | |
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384 | // TODO: handle this better than skipping, e.g. by reset |
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385 | slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte...")); |
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386 | remove (1); |
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387 | } |
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388 | |
361 | if (fill < len + 2) |
389 | if (fill < len + 2) |
362 | return 0; |
390 | return 0; |
363 | |
391 | |
364 | vpn_packet *pkt = new vpn_packet; |
392 | vpn_packet *pkt = new vpn_packet; |
365 | |
393 | |
… | |
… | |
394 | struct dns_cfg |
422 | struct dns_cfg |
395 | { |
423 | { |
396 | static int next_uid; |
424 | static int next_uid; |
397 | |
425 | |
398 | u8 id1, id2, id3, id4; |
426 | u8 id1, id2, id3, id4; |
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427 | |
399 | u8 version; |
428 | u8 version; |
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429 | u8 flags; |
400 | u8 rrtype; |
430 | u8 rrtype; |
401 | u8 flags; |
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402 | u8 def_ttl; |
431 | u8 def_ttl; |
403 | u8 rcv_cdc; |
432 | |
404 | u8 snd_cdc; |
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405 | u16 max_size; |
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406 | u16 client; |
433 | u16 client; |
407 | u16 uid; // to make request unique |
434 | u16 uid; // to make request unique |
408 | |
435 | |
409 | u8 reserved[8]; |
436 | u16 max_size; |
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437 | u8 seq_cdc; |
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438 | u8 req_cdc; |
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439 | |
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440 | u8 rep_cdc; |
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441 | u8 delay; // time in 0.01s units that the server may delay replying packets |
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442 | u8 r3, r4; |
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443 | |
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444 | u8 r5, r6, r7, r8; |
410 | |
445 | |
411 | void reset (int clientid); |
446 | void reset (int clientid); |
412 | bool valid (); |
447 | bool valid (); |
413 | }; |
448 | }; |
414 | |
449 | |
… | |
… | |
424 | version = 1; |
459 | version = 1; |
425 | |
460 | |
426 | rrtype = RR_TYPE_TXT; |
461 | rrtype = RR_TYPE_TXT; |
427 | flags = 0; |
462 | flags = 0; |
428 | def_ttl = 0; |
463 | def_ttl = 0; |
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464 | seq_cdc = 26; |
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465 | req_cdc = 62; |
429 | rcv_cdc = 0; |
466 | rep_cdc = 0; |
430 | snd_cdc = 62; |
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431 | max_size = ntohs (MAX_PKT_SIZE); |
467 | max_size = htons (MAX_PKT_SIZE); |
432 | client = ntohs (clientid); |
468 | client = htons (clientid); |
433 | uid = next_uid++; |
469 | uid = next_uid++; |
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470 | delay = 0; |
434 | |
471 | |
435 | memset (reserved, 0, 8); |
472 | r3 = r4 = 0; |
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473 | r4 = r5 = r6 = r7 = 0; |
436 | } |
474 | } |
437 | |
475 | |
438 | bool dns_cfg::valid () |
476 | bool dns_cfg::valid () |
439 | { |
477 | { |
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478 | // although the protocol itself allows for some configurability, |
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479 | // only the following encoding/decoding settings are implemented. |
440 | return id1 == 'G' |
480 | return id1 == 'G' |
441 | && id2 == 'V' |
481 | && id2 == 'V' |
442 | && id3 == 'P' |
482 | && id3 == 'P' |
443 | && id4 == 'E' |
483 | && id4 == 'E' |
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484 | && seq_cdc == 26 |
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485 | && req_cdc == 62 |
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486 | && rep_cdc == 0 |
444 | && version == 1 |
487 | && version == 1; |
445 | && flags == 0 |
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446 | && rcv_cdc == 0 |
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447 | && snd_cdc == 62 |
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448 | && max_size == ntohs (MAX_PKT_SIZE); |
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449 | } |
488 | } |
450 | |
489 | |
451 | struct dns_packet : net_packet |
490 | struct dns_packet : net_packet |
452 | { |
491 | { |
453 | u16 id; |
492 | u16 id; |
454 | u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 |
493 | u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 |
455 | u16 qdcount, ancount, nscount, arcount; |
494 | u16 qdcount, ancount, nscount, arcount; |
456 | |
495 | |
457 | u8 data[MAXSIZE - 6 * 2]; |
496 | u8 data [MAXSIZE - 6 * 2]; |
458 | |
497 | |
459 | int decode_label (char *data, int size, int &offs); |
498 | int decode_label (char *data, int size, int &offs); |
460 | }; |
499 | }; |
461 | |
500 | |
462 | int dns_packet::decode_label (char *data, int size, int &offs) |
501 | int dns_packet::decode_label (char *data, int size, int &offs) |
… | |
… | |
493 | return data - orig; |
532 | return data - orig; |
494 | } |
533 | } |
495 | |
534 | |
496 | ///////////////////////////////////////////////////////////////////////////// |
535 | ///////////////////////////////////////////////////////////////////////////// |
497 | |
536 | |
498 | struct dns_snd |
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499 | { |
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500 | dns_packet *pkt; |
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501 | tstamp timeout, sent; |
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502 | int retry; |
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503 | struct dns_connection *dns; |
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504 | int seqno; |
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505 | |
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506 | dns_snd (dns_connection *dns); |
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507 | void gen_stream_req (int seqno, byte_stream &stream); |
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508 | void gen_syn_req (const dns_cfg &cfg); |
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509 | }; |
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510 | |
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511 | static u16 dns_id = 12098; // TODO: should be per-vpn |
537 | static u16 dns_id = 0; // TODO: should be per-vpn |
512 | |
538 | |
513 | static u16 next_id () |
539 | static u16 next_id () |
514 | { |
540 | { |
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541 | if (!dns_id) |
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542 | dns_id = time (0); |
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543 | |
515 | // the simplest lsfr with periodicity 65535 i could find |
544 | // the simplest lsfr with periodicity 65535 i could find |
516 | dns_id = (dns_id << 1) |
545 | dns_id = (dns_id << 1) |
517 | | (((dns_id >> 1) |
546 | | (((dns_id >> 1) |
518 | ^ (dns_id >> 2) |
547 | ^ (dns_id >> 2) |
519 | ^ (dns_id >> 4) |
548 | ^ (dns_id >> 4) |
520 | ^ (dns_id >> 15)) & 1); |
549 | ^ (dns_id >> 15)) & 1); |
521 | |
550 | |
522 | return dns_id; |
551 | return dns_id; |
523 | } |
552 | } |
524 | |
553 | |
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554 | struct dns_rcv; |
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555 | struct dns_snd; |
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556 | |
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557 | struct dns_connection |
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558 | { |
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559 | connection *c; |
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560 | struct vpn *vpn; |
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561 | |
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562 | dns_cfg cfg; |
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563 | |
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564 | bool established; |
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565 | |
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566 | tstamp last_received; |
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567 | tstamp last_sent; |
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568 | double min_latency; |
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569 | double poll_interval, send_interval; |
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570 | |
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571 | vector<dns_rcv *> rcvpq; |
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572 | |
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573 | byte_stream rcvdq; int rcvseq; int repseq; |
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574 | byte_stream snddq; int sndseq; |
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575 | |
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576 | inline void time_cb (ev::timer &w, int revents); ev::timer tw; |
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577 | void receive_rep (dns_rcv *r); |
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578 | |
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579 | dns_connection (connection *c); |
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580 | ~dns_connection (); |
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581 | }; |
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582 | |
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583 | struct dns_snd |
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584 | { |
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585 | dns_packet *pkt; |
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586 | tstamp timeout, sent; |
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587 | int retry; |
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588 | struct dns_connection *dns; |
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589 | int seqno; |
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590 | bool stdhdr; |
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591 | |
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592 | void gen_stream_req (int seqno, byte_stream &stream); |
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593 | void gen_syn_req (); |
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594 | |
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595 | dns_snd (dns_connection *dns); |
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596 | ~dns_snd (); |
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597 | }; |
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598 | |
525 | dns_snd::dns_snd (dns_connection *dns) |
599 | dns_snd::dns_snd (dns_connection *dns) |
526 | : dns (dns) |
600 | : dns (dns) |
527 | { |
601 | { |
528 | timeout = 0; |
602 | timeout = 0; |
529 | retry = 0; |
603 | retry = 0; |
530 | seqno = 0; |
604 | seqno = 0; |
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605 | sent = ev_now (); |
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606 | stdhdr = false; |
531 | |
607 | |
532 | pkt = new dns_packet; |
608 | pkt = new dns_packet; |
533 | |
609 | |
534 | pkt->id = next_id (); |
610 | pkt->id = next_id (); |
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611 | } |
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612 | |
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613 | dns_snd::~dns_snd () |
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614 | { |
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615 | delete pkt; |
535 | } |
616 | } |
536 | |
617 | |
537 | static void append_domain (dns_packet &pkt, int &offs, const char *domain) |
618 | static void append_domain (dns_packet &pkt, int &offs, const char *domain) |
538 | { |
619 | { |
539 | // add tunnel domain |
620 | // add tunnel domain |
… | |
… | |
557 | } |
638 | } |
558 | } |
639 | } |
559 | |
640 | |
560 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
641 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
561 | { |
642 | { |
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643 | stdhdr = true; |
562 | this->seqno = seqno; |
644 | this->seqno = seqno; |
563 | |
645 | |
564 | timeout = NOW + INITIAL_TIMEOUT; |
646 | timeout = ev_now () + INITIAL_TIMEOUT; |
565 | |
647 | |
566 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
648 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
567 | pkt->qdcount = htons (1); |
649 | pkt->qdcount = htons (1); |
568 | |
650 | |
569 | int offs = 6*2; |
651 | int offs = 6*2; |
570 | int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); |
652 | int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2); |
571 | // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, |
653 | // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, |
572 | // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra |
654 | // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra |
573 | |
655 | |
574 | char enc[256], *encp = enc; |
656 | char enc[256], *encp = enc; |
575 | encode_header (enc, THISNODE->id, seqno); |
657 | encode_header (enc, THISNODE->id, seqno); |
… | |
… | |
593 | encp += lbllen; |
675 | encp += lbllen; |
594 | |
676 | |
595 | enclen -= lbllen; |
677 | enclen -= lbllen; |
596 | } |
678 | } |
597 | |
679 | |
598 | append_domain (*pkt, offs, THISNODE->domain); |
680 | append_domain (*pkt, offs, dns->c->conf->domain); |
599 | |
681 | |
600 | (*pkt)[offs++] = 0; |
682 | (*pkt)[offs++] = 0; |
601 | (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; |
683 | (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; |
602 | (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
684 | (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
603 | |
685 | |
604 | pkt->len = offs; |
686 | pkt->len = offs; |
605 | } |
687 | } |
606 | |
688 | |
607 | void dns_snd::gen_syn_req (const dns_cfg &cfg) |
689 | void dns_snd::gen_syn_req () |
608 | { |
690 | { |
609 | timeout = NOW + INITIAL_SYN_TIMEOUT; |
691 | timeout = ev_now () + INITIAL_SYN_TIMEOUT; |
610 | |
692 | |
611 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
693 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
612 | pkt->qdcount = htons (1); |
694 | pkt->qdcount = htons (1); |
613 | |
695 | |
614 | int offs = 6*2; |
696 | int offs = 6 * 2; |
615 | |
697 | |
616 | int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&cfg, sizeof (dns_cfg)); |
698 | int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg)); |
617 | |
699 | |
618 | assert (elen <= MAX_LBL_SIZE); |
700 | assert (elen <= MAX_LBL_SIZE); |
619 | |
701 | |
620 | (*pkt)[offs] = elen; |
702 | (*pkt)[offs] = elen; |
621 | offs += elen + 1; |
703 | offs += elen + 1; |
622 | append_domain (*pkt, offs, THISNODE->domain); |
704 | append_domain (*pkt, offs, dns->c->conf->domain); |
623 | |
705 | |
624 | (*pkt)[offs++] = 0; |
706 | (*pkt)[offs++] = 0; |
625 | (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; |
707 | (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; |
626 | (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
708 | (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
627 | |
709 | |
… | |
… | |
650 | delete pkt; |
732 | delete pkt; |
651 | } |
733 | } |
652 | |
734 | |
653 | ///////////////////////////////////////////////////////////////////////////// |
735 | ///////////////////////////////////////////////////////////////////////////// |
654 | |
736 | |
655 | struct dns_connection |
|
|
656 | { |
|
|
657 | connection *c; |
|
|
658 | struct vpn *vpn; |
|
|
659 | |
|
|
660 | dns_cfg cfg; |
|
|
661 | |
|
|
662 | bool established; |
|
|
663 | |
|
|
664 | tstamp last_received; |
|
|
665 | tstamp last_sent; |
|
|
666 | double poll_interval, send_interval; |
|
|
667 | |
|
|
668 | vector<dns_rcv *> rcvpq; |
|
|
669 | |
|
|
670 | byte_stream rcvdq; int rcvseq; |
|
|
671 | byte_stream snddq; int sndseq; |
|
|
672 | |
|
|
673 | void time_cb (time_watcher &w); time_watcher tw; |
|
|
674 | void receive_rep (dns_rcv *r); |
|
|
675 | |
|
|
676 | dns_connection (connection *c); |
|
|
677 | ~dns_connection (); |
|
|
678 | }; |
|
|
679 | |
|
|
680 | dns_connection::dns_connection (connection *c) |
737 | dns_connection::dns_connection (connection *c) |
681 | : c (c) |
738 | : c (c) |
682 | , rcvdq (MAX_BACKLOG * 2) |
739 | , rcvdq (MAX_BACKLOG * 2) |
683 | , snddq (MAX_BACKLOG * 2) |
740 | , snddq (MAX_BACKLOG) |
684 | , tw (this, &dns_connection::time_cb) |
|
|
685 | { |
741 | { |
|
|
742 | tw.set<dns_connection, &dns_connection::time_cb> (this); |
|
|
743 | |
686 | vpn = c->vpn; |
744 | vpn = c->vpn; |
687 | |
745 | |
688 | established = false; |
746 | established = false; |
689 | |
747 | |
690 | rcvseq = sndseq = 0; |
748 | rcvseq = repseq = sndseq = 0; |
691 | |
749 | |
692 | last_sent = last_received = 0; |
750 | last_sent = last_received = 0; |
693 | poll_interval = MIN_POLL_INTERVAL; |
751 | poll_interval = 0.5; // starting here |
694 | send_interval = 0.2; // starting rate |
752 | send_interval = 0.5; // starting rate |
|
|
753 | min_latency = INITIAL_TIMEOUT; |
695 | } |
754 | } |
696 | |
755 | |
697 | dns_connection::~dns_connection () |
756 | dns_connection::~dns_connection () |
698 | { |
757 | { |
699 | for (vector<dns_rcv *>::iterator i = rcvpq.begin (); |
758 | for (vector<dns_rcv *>::iterator i = rcvpq.begin (); |
… | |
… | |
704 | |
763 | |
705 | void dns_connection::receive_rep (dns_rcv *r) |
764 | void dns_connection::receive_rep (dns_rcv *r) |
706 | { |
765 | { |
707 | if (r->datalen) |
766 | if (r->datalen) |
708 | { |
767 | { |
709 | last_received = NOW; |
768 | last_received = ev_now (); |
710 | tw.trigger (); |
769 | tw (); |
711 | |
770 | |
712 | poll_interval *= 0.99; |
771 | poll_interval = send_interval; |
713 | if (poll_interval > MIN_POLL_INTERVAL) |
|
|
714 | poll_interval = MIN_POLL_INTERVAL; |
|
|
715 | } |
772 | } |
716 | else |
773 | else |
717 | { |
774 | { |
718 | poll_interval *= 1.1; |
775 | poll_interval *= 1.5; |
|
|
776 | |
719 | if (poll_interval > MAX_POLL_INTERVAL) |
777 | if (poll_interval > MAX_POLL_INTERVAL) |
720 | poll_interval = MAX_POLL_INTERVAL; |
778 | poll_interval = MAX_POLL_INTERVAL; |
721 | } |
779 | } |
722 | |
780 | |
723 | rcvpq.push_back (r); |
781 | rcvpq.push_back (r); |
… | |
… | |
726 | |
784 | |
727 | // find next packet |
785 | // find next packet |
728 | for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
786 | for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
729 | if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
787 | if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
730 | { |
788 | { |
|
|
789 | //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D |
731 | // enter the packet into our input stream |
790 | // enter the packet into our input stream |
732 | r = *i; |
791 | r = *i; |
733 | |
792 | |
734 | // remove the oldest packet, look forward, as it's oldest first |
793 | // remove the oldest packet, look forward, as it's oldest first |
735 | for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
794 | for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
736 | if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
795 | if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
737 | { |
796 | { |
|
|
797 | //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D |
738 | delete *j; |
798 | delete *j; |
739 | rcvpq.erase (j); |
799 | rcvpq.erase (j); |
740 | break; |
800 | break; |
741 | } |
801 | } |
742 | |
802 | |
743 | rcvseq = (rcvseq + 1) & SEQNO_MASK; |
803 | rcvseq = (rcvseq + 1) & SEQNO_MASK; |
744 | |
804 | |
745 | if (!rcvdq.put (r->data, r->datalen)) |
805 | if (!rcvdq.put (r->data, r->datalen)) |
|
|
806 | { |
|
|
807 | slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)"); |
746 | abort (); // MUST never overflow, can be caused by data corruption, TODO |
808 | abort (); // MUST never overflow, can be caused by data corruption, TODO |
|
|
809 | } |
747 | |
810 | |
748 | while (vpn_packet *pkt = rcvdq.get ()) |
811 | while (vpn_packet *pkt = rcvdq.get ()) |
749 | { |
812 | { |
750 | sockinfo si; |
813 | sockinfo si; |
751 | si.host = 0; si.port = 0; si.prot = PROT_DNSv4; |
814 | si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; |
752 | |
815 | |
753 | vpn->recv_vpn_packet (pkt, si); |
816 | vpn->recv_vpn_packet (pkt, si); |
|
|
817 | |
|
|
818 | delete pkt; |
754 | } |
819 | } |
755 | |
820 | |
756 | // check for further packets |
821 | // check for further packets |
757 | goto redo; |
822 | goto redo; |
758 | } |
823 | } |
… | |
… | |
768 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
833 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
769 | |
834 | |
770 | if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) |
835 | if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) |
771 | && pkt.qdcount == htons (1)) |
836 | && pkt.qdcount == htons (1)) |
772 | { |
837 | { |
773 | char qname[MAXSIZE]; |
838 | char qname [MAXSIZE]; |
774 | int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); |
839 | int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); |
775 | |
840 | |
776 | u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; |
841 | u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; |
777 | u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; |
842 | u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; |
778 | |
843 | |
779 | pkt.qdcount = htons (1); |
844 | pkt.qdcount = htons (1); |
780 | pkt.ancount = 0; |
845 | pkt.ancount = 0; |
781 | pkt.nscount = 0; // should be self, as other nameservers reply like this |
846 | pkt.nscount = 0; // should be self, as other nameservers reply like this |
782 | pkt.arcount = 0; // a record for self, as other nameservers reply like this |
847 | pkt.arcount = 0; // a record for self, as other nameservers reply like this |
783 | |
848 | |
784 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_NXDOMAIN); |
849 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_SERVFAIL); |
785 | |
850 | |
786 | int dlen = strlen (THISNODE->domain); |
851 | int dlen = strlen (THISNODE->domain); |
787 | |
852 | |
788 | if (qclass == RR_CLASS_IN |
853 | if (qclass == RR_CLASS_IN |
789 | && qlen > dlen + 1 |
854 | && qlen > dlen + 1 |
790 | && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) |
855 | && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen)) |
791 | { |
856 | { |
792 | // now generate reply |
857 | // now generate reply |
793 | pkt.ancount = htons (1); // one answer RR |
858 | pkt.ancount = htons (1); // one answer RR |
794 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); |
859 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); |
795 | |
860 | |
… | |
… | |
817 | if (SEQNO_EQ ((*i)->seqno, seqno)) |
882 | if (SEQNO_EQ ((*i)->seqno, seqno)) |
818 | { |
883 | { |
819 | // already seen that request: simply reply with the cached reply |
884 | // already seen that request: simply reply with the cached reply |
820 | dns_rcv *r = *i; |
885 | dns_rcv *r = *i; |
821 | |
886 | |
822 | printf ("DUPLICATE %d\n", htons (r->pkt->id));//D |
887 | slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno); |
|
|
888 | |
|
|
889 | // refresh header & id, as the retry count could have changed |
|
|
890 | memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE); |
|
|
891 | r->pkt->id = pkt.id; |
823 | |
892 | |
824 | memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); |
893 | memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); |
825 | pkt.id = r->pkt->id; |
894 | |
826 | goto duplicate_request; |
895 | goto duplicate_request; |
827 | } |
896 | } |
828 | |
897 | |
829 | // new packet, queue |
898 | // new packet, queue |
830 | rcv = new dns_rcv (seqno, data, datalen); |
899 | rcv = new dns_rcv (seqno, data, datalen); |
831 | dns->receive_rep (rcv); |
900 | dns->receive_rep (rcv); |
832 | } |
901 | } |
833 | |
902 | |
|
|
903 | { |
834 | pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section |
904 | pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section |
835 | |
905 | |
836 | // type |
|
|
837 | int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; |
906 | int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; |
838 | pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; |
907 | pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type |
839 | |
|
|
840 | // class |
|
|
841 | pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; |
908 | pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
842 | |
|
|
843 | // TTL |
|
|
844 | pkt [offs++] = 0; pkt [offs++] = 0; |
909 | pkt [offs++] = 0; pkt [offs++] = 0; |
845 | pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; |
910 | pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL |
846 | |
911 | |
847 | int rdlen_offs = offs += 2; |
912 | int rdlen_offs = offs += 2; |
848 | |
913 | |
|
|
914 | if (dns) |
|
|
915 | { |
849 | int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; |
916 | int dlen = ntohs (dns->cfg.max_size) - offs; |
|
|
917 | |
850 | // bind doesn't compress well, so reduce further by one label length |
918 | // bind doesn't compress well, so reduce further by one label length |
851 | dlen -= qlen; |
919 | dlen -= qlen; |
852 | |
920 | |
853 | if (dns) |
921 | // only put data into in-order sequence packets, if |
854 | { |
922 | // we receive out-of-order packets we generate empty |
855 | while (dlen > 1 && !dns->snddq.empty ()) |
923 | // replies |
|
|
924 | //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D |
|
|
925 | if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW) |
856 | { |
926 | { |
|
|
927 | dns->repseq = seqno; |
|
|
928 | |
|
|
929 | while (dlen > 1 && !dns->snddq.empty ()) |
|
|
930 | { |
857 | int txtlen = dlen <= 255 ? dlen - 1 : 255; |
931 | int txtlen = dlen <= 255 ? dlen - 1 : 255; |
858 | |
932 | |
859 | if (txtlen > dns->snddq.size ()) |
933 | if (txtlen > dns->snddq.size ()) |
860 | txtlen = dns->snddq.size (); |
934 | txtlen = dns->snddq.size (); |
861 | |
935 | |
862 | pkt[offs++] = txtlen; |
936 | pkt[offs++] = txtlen; |
863 | memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); |
937 | memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); |
864 | offs += txtlen; |
938 | offs += txtlen; |
865 | dns->snddq.remove (txtlen); |
939 | dns->snddq.remove (txtlen); |
866 | |
940 | |
867 | dlen -= txtlen + 1; |
941 | dlen -= txtlen + 1; |
|
|
942 | } |
868 | } |
943 | } |
869 | |
944 | |
870 | // avoid empty TXT rdata |
945 | // avoid completely empty TXT rdata |
871 | if (offs == rdlen_offs) |
946 | if (offs == rdlen_offs) |
872 | pkt[offs++] = 0; |
947 | pkt[offs++] = 0; |
|
|
948 | |
|
|
949 | slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); |
873 | } |
950 | } |
874 | else |
951 | else |
875 | { |
952 | { |
876 | // send RST |
953 | // send RST |
877 | pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
954 | pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
878 | pkt [offs++] = CMD_IP_RST; |
955 | pkt [offs++] = CMD_IP_RST; |
879 | } |
956 | } |
880 | |
957 | |
881 | int rdlen = offs - rdlen_offs; |
958 | int rdlen = offs - rdlen_offs; |
882 | |
959 | |
883 | pkt [rdlen_offs - 2] = rdlen >> 8; |
960 | pkt [rdlen_offs - 2] = rdlen >> 8; |
884 | pkt [rdlen_offs - 1] = rdlen; |
961 | pkt [rdlen_offs - 1] = rdlen; |
885 | |
962 | |
886 | if (dns) |
963 | if (dns) |
887 | { |
964 | { |
888 | // now update dns_rcv copy |
965 | // now update dns_rcv copy |
889 | rcv->pkt->len = offs; |
966 | rcv->pkt->len = offs; |
890 | memcpy (rcv->pkt->at (0), pkt.at (0), offs); |
967 | memcpy (rcv->pkt->at (0), pkt.at (0), offs); |
891 | } |
968 | } |
|
|
969 | } |
892 | |
970 | |
893 | duplicate_request: ; |
971 | duplicate_request: ; |
894 | } |
972 | } |
895 | else |
973 | else |
896 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
974 | pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
… | |
… | |
908 | pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
986 | pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
909 | pkt [offs++] = 0; pkt [offs++] = 0; |
987 | pkt [offs++] = 0; pkt [offs++] = 0; |
910 | pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL |
988 | pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL |
911 | pkt [offs++] = 0; pkt [offs++] = 4; // rdlength |
989 | pkt [offs++] = 0; pkt [offs++] = 4; // rdlength |
912 | |
990 | |
913 | slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client); |
991 | slog (L_INFO, _("DNS: client %d connects"), client); |
914 | |
992 | |
915 | pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
993 | pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
916 | pkt [offs++] = CMD_IP_REJ; |
994 | pkt [offs++] = CMD_IP_REJ; |
917 | |
995 | |
918 | if (0 < client && client <= conns.size ()) |
996 | if (0 < client && client <= conns.size ()) |
… | |
… | |
949 | i != dns_sndpq.end (); |
1027 | i != dns_sndpq.end (); |
950 | ++i) |
1028 | ++i) |
951 | if ((*i)->pkt->id == pkt.id) |
1029 | if ((*i)->pkt->id == pkt.id) |
952 | { |
1030 | { |
953 | dns_connection *dns = (*i)->dns; |
1031 | dns_connection *dns = (*i)->dns; |
|
|
1032 | connection *c = dns->c; |
954 | int seqno = (*i)->seqno; |
1033 | int seqno = (*i)->seqno; |
955 | u8 data[MAXSIZE], *datap = data; |
1034 | u8 data[MAXSIZE], *datap = data; |
|
|
1035 | //printf ("rcv pkt %x\n", seqno);//D |
956 | |
1036 | |
957 | if ((*i)->retry) |
1037 | if ((*i)->retry) |
958 | { |
1038 | { |
959 | dns->send_interval *= 1.01; |
1039 | dns->send_interval *= 1.01; |
960 | if (dns->send_interval < MAX_SEND_INTERVAL) |
1040 | if (dns->send_interval > MAX_SEND_INTERVAL) |
961 | dns->send_interval = MAX_SEND_INTERVAL; |
1041 | dns->send_interval = MAX_SEND_INTERVAL; |
962 | } |
1042 | } |
963 | else |
1043 | else |
964 | { |
1044 | { |
|
|
1045 | #if 0 |
965 | dns->send_interval *= 0.99; |
1046 | dns->send_interval *= 0.999; |
966 | if (dns->send_interval < MIN_SEND_INTERVAL) |
1047 | #endif |
967 | dns->send_interval = MIN_SEND_INTERVAL; |
|
|
968 | |
|
|
969 | // the latency surely puts an upper bound on |
1048 | // the latency surely puts an upper bound on |
970 | // the minimum send interval |
1049 | // the minimum send interval |
971 | if (dns->send_interval > NOW - (*i)->sent) |
1050 | double latency = ev_now () - (*i)->sent; |
972 | dns->send_interval = NOW - (*i)->sent; |
1051 | |
|
|
1052 | if (latency < dns->min_latency) |
|
|
1053 | dns->min_latency = latency; |
|
|
1054 | |
|
|
1055 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
|
|
1056 | dns->send_interval = dns->min_latency * conf.dns_overlap_factor; |
|
|
1057 | |
|
|
1058 | if (dns->send_interval < conf.dns_send_interval) |
|
|
1059 | dns->send_interval = conf.dns_send_interval; |
973 | } |
1060 | } |
974 | |
1061 | |
975 | delete *i; |
1062 | delete *i; |
976 | dns_sndpq.erase (i); |
1063 | dns_sndpq.erase (i); |
977 | |
1064 | |
… | |
… | |
1027 | |
1114 | |
1028 | if (ip [0] == CMD_IP_1 |
1115 | if (ip [0] == CMD_IP_1 |
1029 | && ip [1] == CMD_IP_2 |
1116 | && ip [1] == CMD_IP_2 |
1030 | && ip [2] == CMD_IP_3) |
1117 | && ip [2] == CMD_IP_3) |
1031 | { |
1118 | { |
1032 | slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]); |
1119 | slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); |
1033 | |
1120 | |
1034 | if (ip [3] == CMD_IP_RST) |
1121 | if (ip [3] == CMD_IP_RST) |
1035 | { |
1122 | { |
1036 | slog (L_DEBUG, _("got tunnel RST request")); |
1123 | slog (L_DEBUG, _("DNS: got tunnel RST request")); |
1037 | |
1124 | |
1038 | connection *c = dns->c; |
|
|
1039 | delete c->dns; c->dns = 0; |
1125 | delete dns; c->dns = 0; |
1040 | |
1126 | |
1041 | return; |
1127 | return; |
1042 | } |
1128 | } |
1043 | else if (ip [3] == CMD_IP_SYN) |
1129 | else if (ip [3] == CMD_IP_SYN) |
|
|
1130 | { |
|
|
1131 | slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); |
1044 | dns->established = true; |
1132 | dns->established = true; |
|
|
1133 | } |
|
|
1134 | else if (ip [3] == CMD_IP_REJ) |
|
|
1135 | { |
|
|
1136 | slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting.")); |
|
|
1137 | abort (); |
|
|
1138 | } |
1045 | else |
1139 | else |
1046 | slog (L_INFO, _("got unknown meta command %02x"), ip [3]); |
1140 | slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); |
1047 | } |
1141 | } |
1048 | else |
1142 | else |
1049 | slog (L_INFO, _("got spurious a record %d.%d.%d.%d"), |
1143 | slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), |
1050 | ip [0], ip [1], ip [2], ip [3]); |
1144 | ip [0], ip [1], ip [2], ip [3]); |
1051 | |
1145 | |
1052 | return; |
1146 | return; |
1053 | } |
1147 | } |
1054 | |
1148 | |
1055 | int client, rseqno; |
1149 | int client, rseqno; |
1056 | decode_header (qname, client, rseqno); |
1150 | decode_header (qname, client, rseqno); |
1057 | |
1151 | |
1058 | if (client != THISNODE->id) |
1152 | if (client != THISNODE->id) |
1059 | { |
1153 | { |
1060 | slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring")); |
1154 | slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring")); |
1061 | datap = 0; |
1155 | datap = 0; |
1062 | } |
1156 | } |
1063 | else if (rseqno != seqno) |
1157 | else if (rseqno != seqno) |
1064 | { |
1158 | { |
1065 | slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?")); |
1159 | slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?")); |
1066 | datap = 0; |
1160 | datap = 0; |
1067 | } |
1161 | } |
1068 | } |
1162 | } |
1069 | } |
1163 | } |
1070 | |
1164 | |
… | |
… | |
1075 | break; |
1169 | break; |
1076 | } |
1170 | } |
1077 | } |
1171 | } |
1078 | |
1172 | |
1079 | void |
1173 | void |
1080 | vpn::dnsv4_ev (io_watcher &w, short revents) |
1174 | vpn::dnsv4_ev (ev::io &w, int revents) |
1081 | { |
1175 | { |
1082 | if (revents & EVENT_READ) |
1176 | if (revents & EV_READ) |
1083 | { |
1177 | { |
1084 | dns_packet *pkt = new dns_packet; |
1178 | dns_packet *pkt = new dns_packet; |
1085 | struct sockaddr_in sa; |
1179 | struct sockaddr_in sa; |
1086 | socklen_t sa_len = sizeof (sa); |
1180 | socklen_t sa_len = sizeof (sa); |
1087 | |
1181 | |
1088 | pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); |
1182 | pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); |
1089 | |
1183 | |
1090 | if (pkt->len > 0) |
1184 | if (pkt->len > 0) |
1091 | { |
1185 | { |
1092 | if (THISNODE->dns_port) |
1186 | if (ntohs (pkt->flags) & FLAG_RESPONSE) |
|
|
1187 | dnsv4_client (*pkt); |
|
|
1188 | else |
1093 | { |
1189 | { |
1094 | dnsv4_server (*pkt); |
1190 | dnsv4_server (*pkt); |
1095 | sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); |
1191 | sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); |
1096 | } |
1192 | } |
1097 | else |
|
|
1098 | dnsv4_client (*pkt); |
|
|
1099 | |
1193 | |
1100 | delete pkt; |
1194 | delete pkt; |
1101 | } |
1195 | } |
1102 | } |
1196 | } |
1103 | } |
1197 | } |
1104 | |
1198 | |
1105 | bool |
1199 | bool |
1106 | connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
1200 | vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
1107 | { |
1201 | { |
|
|
1202 | int client = ntohl (si.host); |
|
|
1203 | |
|
|
1204 | assert (0 < client && client <= conns.size ()); |
|
|
1205 | |
|
|
1206 | connection *c = conns [client - 1]; |
|
|
1207 | |
1108 | if (!dns) |
1208 | if (!c->dns) |
1109 | dns = new dns_connection (this); |
1209 | c->dns = new dns_connection (c); |
1110 | |
1210 | |
1111 | if (!dns->snddq.put (pkt)) |
1211 | if (c->dns->snddq.put (pkt)) |
1112 | return false; |
1212 | c->dns->tw (); |
1113 | |
1213 | |
1114 | dns->tw.trigger (); |
1214 | // always return true even if the buffer overflows |
1115 | |
|
|
1116 | return true; |
1215 | return true; |
1117 | } |
1216 | } |
1118 | |
1217 | |
|
|
1218 | void |
|
|
1219 | connection::dnsv4_reset_connection () |
|
|
1220 | { |
|
|
1221 | //delete dns; dns = 0; //TODO |
|
|
1222 | } |
|
|
1223 | |
1119 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
1224 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
1120 | |
1225 | |
1121 | void |
1226 | void |
1122 | dns_connection::time_cb (time_watcher &w) |
1227 | dns_connection::time_cb (ev::timer &w, int revents) |
1123 | { |
1228 | { |
1124 | // servers have to be polled |
1229 | // servers have to be polled |
1125 | if (THISNODE->dns_port) |
1230 | if (THISNODE->dns_port) |
1126 | return; |
1231 | return; |
1127 | |
1232 | |
1128 | // check for timeouts and (re)transmit |
1233 | // check for timeouts and (re)transmit |
1129 | tstamp next = NOW + poll_interval; |
1234 | tstamp next = ev::now () + poll_interval; |
1130 | dns_snd *send = 0; |
1235 | dns_snd *send = 0; |
1131 | |
1236 | |
1132 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1237 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1133 | i != vpn->dns_sndpq.end (); |
1238 | i != vpn->dns_sndpq.end (); |
1134 | ++i) |
1239 | ++i) |
1135 | { |
1240 | { |
1136 | dns_snd *r = *i; |
1241 | dns_snd *r = *i; |
1137 | |
1242 | |
1138 | if (r->timeout <= NOW) |
1243 | if (r->timeout <= ev_now ()) |
1139 | { |
1244 | { |
1140 | if (!send) |
1245 | if (!send) |
1141 | { |
1246 | { |
1142 | send = r; |
1247 | send = r; |
1143 | |
1248 | |
1144 | r->retry++; |
1249 | r->retry++; |
1145 | r->timeout = NOW + r->retry; |
1250 | r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); |
|
|
1251 | //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D |
|
|
1252 | |
|
|
1253 | // the following code changes the query section a bit, forcing |
|
|
1254 | // the forwarder to generate a new request |
|
|
1255 | if (r->stdhdr) |
|
|
1256 | encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); |
1146 | } |
1257 | } |
1147 | } |
1258 | } |
1148 | else if (r->timeout < next) |
1259 | else |
1149 | NEXT (r->timeout); |
1260 | NEXT (r->timeout); |
1150 | } |
1261 | } |
1151 | |
1262 | |
1152 | if (last_sent + send_interval <= NOW) |
|
|
1153 | { |
|
|
1154 | if (!send) |
1263 | if (!send) |
|
|
1264 | { |
|
|
1265 | // generate a new packet, if wise |
|
|
1266 | |
|
|
1267 | if (!established) |
1155 | { |
1268 | { |
1156 | // generate a new packet, if wise |
|
|
1157 | |
|
|
1158 | if (!established) |
|
|
1159 | { |
|
|
1160 | if (vpn->dns_sndpq.empty ()) |
1269 | if (vpn->dns_sndpq.empty ()) |
1161 | { |
|
|
1162 | send = new dns_snd (this); |
|
|
1163 | |
|
|
1164 | cfg.reset (THISNODE->id); |
|
|
1165 | send->gen_syn_req (cfg); |
|
|
1166 | } |
|
|
1167 | } |
|
|
1168 | else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING) |
|
|
1169 | { |
1270 | { |
1170 | send = new dns_snd (this); |
1271 | send = new dns_snd (this); |
|
|
1272 | |
|
|
1273 | cfg.reset (THISNODE->id); |
|
|
1274 | send->gen_syn_req (); |
|
|
1275 | } |
|
|
1276 | } |
|
|
1277 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
|
|
1278 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
|
|
1279 | { |
|
|
1280 | if (last_sent + send_interval <= ev_now ()) |
|
|
1281 | { |
|
|
1282 | //printf ("sending data request etc.\n"); //D |
|
|
1283 | if (!snddq.empty () || last_received + 1. > ev_now ()) |
|
|
1284 | { |
|
|
1285 | poll_interval = send_interval; |
|
|
1286 | NEXT (ev_now () + send_interval); |
|
|
1287 | } |
|
|
1288 | |
|
|
1289 | send = new dns_snd (this); |
1171 | send->gen_stream_req (sndseq, snddq); |
1290 | send->gen_stream_req (sndseq, snddq); |
|
|
1291 | send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; |
|
|
1292 | //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D |
1172 | |
1293 | |
1173 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1294 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1174 | } |
1295 | } |
1175 | |
1296 | else |
1176 | if (send) |
1297 | NEXT (last_sent + send_interval); |
1177 | vpn->dns_sndpq.push_back (send); |
|
|
1178 | } |
1298 | } |
1179 | |
1299 | |
1180 | if (send) |
1300 | if (send) |
1181 | { |
1301 | vpn->dns_sndpq.push_back (send); |
1182 | printf ("send pkt\n"); |
1302 | } |
1183 | last_sent = NOW; |
|
|
1184 | |
1303 | |
1185 | if (!send->retry) |
1304 | if (send) |
1186 | send->sent = NOW; |
1305 | { |
1187 | |
1306 | last_sent = ev_now (); |
1188 | sendto (vpn->dnsv4_fd, |
1307 | sendto (vpn->dnsv4_fd, |
1189 | send->pkt->at (0), send->pkt->len, 0, |
1308 | send->pkt->at (0), send->pkt->len, 0, |
1190 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1309 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1191 | } |
|
|
1192 | } |
1310 | } |
1193 | else |
|
|
1194 | NEXT (last_sent + send_interval); |
|
|
1195 | |
1311 | |
1196 | printf ("pi %f si %f N %f (%d:%d)\n", poll_interval, send_interval, next - NOW, vpn->dns_sndpq.size (), snddq.size ()); |
1312 | slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", |
|
|
1313 | poll_interval, send_interval, next - ev_now (), |
|
|
1314 | vpn->dns_sndpq.size (), snddq.size (), |
|
|
1315 | rcvpq.size ()); |
1197 | |
1316 | |
1198 | w.start (next); |
1317 | // TODO: no idea when this happens, but when next < ev_now (), we have a problem |
|
|
1318 | // doesn't seem to happen anymore |
|
|
1319 | if (next < ev_now () + 0.001) |
|
|
1320 | next = ev_now () + 0.1; |
|
|
1321 | |
|
|
1322 | w.start (next - ev_now ()); |
1199 | } |
1323 | } |
1200 | |
1324 | |
1201 | #endif |
1325 | #endif |
1202 | |
1326 | |