[ViewVC] Diff of: cvs/gvpe/src/vpn

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs.
Revision 1.46 by pcg, Thu Dec 6 00:35:29 2007 UTC

…		…
14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15	GNU General Public License for more details.	15	GNU General 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
18	along with gvpe; if not, write to the Free Software	18	along with gvpe; if not, write to the Free Software
19	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA	19	Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20	*/	20	*/
		21
		22	// TODO: EDNS0 option to increase dns mtu?
		23	// TODO: re-write dns packet parsing/creation using a safe mem-buffer
		24	// to ensure no buffer overflows or similar problems.
21		25
22	#include "config.h"	26	#include "config.h"
23		27
24	#if ENABLE_DNS	28	#if ENABLE_DNS
25		29
26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.	30	// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27	// it's a hack, use only in emergency situations please.	31	// it's a hack, use only in emergency situations please.
28		32
29	#include <cstring>	33	#include <cstring>
		34	#include <cassert>
30		35
31	#include <sys/types.h>	36	#include <sys/types.h>
32	#include <sys/socket.h>	37	#include <sys/socket.h>
33	#include <sys/wait.h>	38	#include <sys/wait.h>
34	#include <sys/uio.h>	39	#include <sys/uio.h>
…		…
37	#include <unistd.h>	42	#include <unistd.h>
38	#include <fcntl.h>	43	#include <fcntl.h>
39		44
40	#include <map>	45	#include <map>
41		46
		47	#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
42	#include <gmp.h>	48	#include <gmp.h>
43		49
44	#include "netcompat.h"	50	#include "netcompat.h"
45		51
46	#include "vpn.h"	52	#include "vpn.h"
47		53
48	#define MIN_RETRY 1.	54	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
49	#define MAX_RETRY 60.	55	#define ACTIVITY_INTERVAL 5.
50		56
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	57	#define INITIAL_TIMEOUT 0.1 // retry timeouts
		58	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
		59
		60	#define MAX_SEND_INTERVAL 2. // optimistic?
		61
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	62	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
53	#define MAX_RATE 10000 // requests/s
54	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	63	#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55		64
56	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	65	#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well
57	// 240 leaves about 4 bytes of server reply data	66	// 240 leaves about 4 bytes of server reply data
58	// every two request byte sless give room for one reply byte	67	// every request byte less give room for two reply bytes
59		68
60	// seqno has 12 bits (3 bytes a 4 bits in the header)
61	#define SEQNO_MASK 0x7fff	69	#define SEQNO_MASK 0x3fff
62	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	70	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
63		71
64	#define MAX_LBL_SIZE 63	72	#define MAX_LBL_SIZE 63
65	#define MAX_PKT_SIZE 512	73	#define MAX_PKT_SIZE 512
66		74
		75	#define RR_TYPE_A 1
		76	#define RR_TYPE_NULL 10
67	#define RR_TYPE_TXT 16	77	#define RR_TYPE_TXT 16
68	#define RR_TYPE_ANY 255	78	#define RR_TYPE_ANY 255
		79
69	#define RR_CLASS_IN 1	80	#define RR_CLASS_IN 1
		81
		82	#define CMD_IP_1 207
		83	#define CMD_IP_2 46
		84	#define CMD_IP_3 236
		85	#define CMD_IP_RST 29
		86	#define CMD_IP_SYN 113
		87	#define CMD_IP_REJ 32
70		88
71	// works for cmaps up to 255 (not 256!)	89	// works for cmaps up to 255 (not 256!)
72	struct charmap	90	struct charmap
73	{	91	{
74	enum { INVALID = (u8)255 };	92	enum { INVALID = (u8)255 };
…		…
154	return dec_len [len];	172	return dec_len [len];
155	}	173	}
156		174
157	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	175	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
158	{	176	{
159	if (!len)	177	if (!len \|\| len > MAX_DEC_LEN)
160	return 0;	178	return 0;
161		179
162	int elen = encode_len (len);	180	int elen = encode_len (len);
163		181
164	mp_limb_t m [MAX_LIMBS];	182	mp_limb_t m [MAX_LIMBS];
…		…
183	return elen;	201	return elen;
184	}	202	}
185		203
186	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	204	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
187	{	205	{
188	if (!len)	206	if (!len \|\| len > MAX_ENC_LEN)
189	return 0;	207	return 0;
190		208
191	u8 src_ [MAX_ENC_LEN];	209	u8 src_ [MAX_ENC_LEN];
192	unsigned int elen = 0;	210	unsigned int elen = 0;
193		211
…		…
240	}	258	}
241	abort ();	259	abort ();
242	}	260	}
243	#endif	261	#endif
244		262
245	// the following sequence has been crafted to	263	//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
246	// a) look somewhat random
247	// b) the even (and odd) indices never share the same character as upper/lowercase
248	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)
249	// the other sequences are obviously derived
250	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	264	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	265	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
252	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	266	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
253	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	267	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
254		268
255	/////////////////////////////////////////////////////////////////////////////	269	/////////////////////////////////////////////////////////////////////////////
256		270
257	#define HDRSIZE 6	271	#define HDRSIZE 6
258		272
259	inline void encode_header (char *data, int clientid, int seqno)	273	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
260	{	274	{
261	u8 hdr[3] = { clientid, seqno >> 8, seqno };	275	seqno &= SEQNO_MASK;
		276
		277	u8 hdr[3] = {
		278	clientid,
		279	(seqno >> 8) \| (retry << 6),
		280	seqno,
		281	};
262		282
263	assert (clientid < 256);	283	assert (clientid < 256);
264		284
265	cdc26.encode (data, hdr, 3);	285	cdc26.encode (data, hdr, 3);
266	}	286	}
…		…
269	{	289	{
270	u8 hdr[3];	290	u8 hdr[3];
271		291
272	cdc26.decode (hdr, data, HDRSIZE);	292	cdc26.decode (hdr, data, HDRSIZE);
273		293
274	printf ("DEC %02x %02x %02x %02x\n", hdr[0], hdr[1], hdr[2], hdr[3]);
275
276	clientid = hdr[0];	294	clientid = hdr[0];
277	seqno = (hdr[1] << 8) \| hdr[2];	295	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
278	}	296	}
279		297
280	/////////////////////////////////////////////////////////////////////////////	298	/////////////////////////////////////////////////////////////////////////////
281		299
282	struct byte_stream	300	struct byte_stream
…		…
311	}	329	}
312		330
313	void byte_stream::remove (int count)	331	void byte_stream::remove (int count)
314	{	332	{
315	if (count > fill)	333	if (count > fill)
316	abort ();	334	assert (count <= fill);
317		335
318	memmove (data, data + count, fill -= count);	336	memmove (data, data + count, fill -= count);
319	}	337	}
320		338
321	bool byte_stream::put (u8 *data, unsigned int datalen)	339	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
334	return false;	352	return false;
335		353
336	data [fill++] = pkt->len >> 8;	354	data [fill++] = pkt->len >> 8;
337	data [fill++] = pkt->len;	355	data [fill++] = pkt->len;
338		356
339	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	357	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
340		358
341	return true;	359	return true;
342	}	360	}
343		361
344	vpn_packet *byte_stream::get ()	362	vpn_packet *byte_stream::get ()
345	{	363	{
		364	unsigned int len;
		365
		366	for (;;)
		367	{
346	int len = (data [0] << 8) \| data [1];	368	len = (data [0] << 8) \| data [1];
347		369
348	if (len > MAXSIZE && fill >= 2)	370	if (len <= MAXSIZE \|\| fill < 2)
349	abort (); // TODO handle this gracefully, connection reset	371	break;
350		372
		373	// TODO: handle this better than skipping, e.g. by reset
		374	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		375	remove (1);
		376	}
		377
351	if (fill < len + 2)	378	if (fill < len + 2)
352	return 0;	379	return 0;
353		380
354	vpn_packet *pkt = new vpn_packet;	381	vpn_packet *pkt = new vpn_packet;
355		382
356	pkt->len = len;	383	pkt->len = len;
357	memcpy (&((*pkt)[0]), data + 2, len);	384	memcpy (pkt->at (0), data + 2, len);
358	remove (len + 2);	385	remove (len + 2);
359		386
360	return pkt;	387	return pkt;
361	}	388	}
362		389
363	/////////////////////////////////////////////////////////////////////////////	390	/////////////////////////////////////////////////////////////////////////////
364		391
365	#define FLAG_QUERY ( 0 << 15)	392	#define FLAG_QUERY ( 0 << 15)
366	#define FLAG_RESPONSE ( 1 << 15)	393	#define FLAG_RESPONSE ( 1 << 15)
367	#define FLAG_OP_MASK (15 << 14)	394	#define FLAG_OP_MASK (15 << 11)
368	#define FLAG_OP_QUERY ( 0 << 11)	395	#define FLAG_OP_QUERY ( 0 << 11)
369	#define FLAG_AA ( 1 << 10)	396	#define FLAG_AA ( 1 << 10)
370	#define FLAG_TC ( 1 << 9)	397	#define FLAG_TC ( 1 << 9)
371	#define FLAG_RD ( 1 << 8)	398	#define FLAG_RD ( 1 << 8)
372	#define FLAG_RA ( 1 << 7)	399	#define FLAG_RA ( 1 << 7)
…		…
379	#define FLAG_RCODE_REFUSED ( 5 << 0)	406	#define FLAG_RCODE_REFUSED ( 5 << 0)
380		407
381	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	408	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
382	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)	409	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
383		410
		411	struct dns_cfg
		412	{
		413	static int next_uid;
		414
		415	u8 id1, id2, id3, id4;
		416
		417	u8 version;
		418	u8 flags;
		419	u8 rrtype;
		420	u8 def_ttl;
		421
		422	u16 client;
		423	u16 uid; // to make request unique
		424
		425	u16 max_size;
		426	u8 seq_cdc;
		427	u8 req_cdc;
		428
		429	u8 rep_cdc;
		430	u8 delay; // time in 0.01s units that the server may delay replying packets
		431	u8 r3, r4;
		432
		433	u8 r5, r6, r7, r8;
		434
		435	void reset (int clientid);
		436	bool valid ();
		437	};
		438
		439	int dns_cfg::next_uid;
		440
		441	void dns_cfg::reset (int clientid)
		442	{
		443	id1 = 'G';
		444	id2 = 'V';
		445	id3 = 'P';
		446	id4 = 'E';
		447
		448	version = 1;
		449
		450	rrtype = RR_TYPE_TXT;
		451	flags = 0;
		452	def_ttl = 0;
		453	seq_cdc = 26;
		454	req_cdc = 62;
		455	rep_cdc = 0;
		456	max_size = htons (MAX_PKT_SIZE);
		457	client = htons (clientid);
		458	uid = next_uid++;
		459	delay = 0;
		460
		461	r3 = r4 = 0;
		462	r4 = r5 = r6 = r7 = 0;
		463	}
		464
		465	bool dns_cfg::valid ()
		466	{
		467	// although the protocol itself allows for some configurability,
		468	// only the following encoding/decoding settings are implemented.
		469	return id1 == 'G'
		470	&& id2 == 'V'
		471	&& id3 == 'P'
		472	&& id4 == 'E'
		473	&& seq_cdc == 26
		474	&& req_cdc == 62
		475	&& rep_cdc == 0
		476	&& version == 1;
		477	}
		478
384	struct dns_packet : net_packet	479	struct dns_packet : net_packet
385	{	480	{
386	u16 id;	481	u16 id;
387	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	482	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
388	u16 qdcount, ancount, nscount, arcount;	483	u16 qdcount, ancount, nscount, arcount;
389		484
390	u8 data[MAXSIZE - 6 * 2];	485	u8 data [MAXSIZE - 6 * 2];
391		486
392	int decode_label (char *data, int size, int &offs);	487	int decode_label (char *data, int size, int &offs);
393	};	488	};
394		489
395	int dns_packet::decode_label (char *data, int size, int &offs)	490	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
426	return data - orig;	521	return data - orig;
427	}	522	}
428		523
429	/////////////////////////////////////////////////////////////////////////////	524	/////////////////////////////////////////////////////////////////////////////
430		525
431	struct dns_req
432	{
433	dns_packet *pkt;
434	tstamp next;
435	int retry;
436	connection *conn;
437	int seqno;
438
439	dns_req (connection *c);
440	void gen_stream_req (int seqno, byte_stream *stream);
441	};
442
443	static u16 dns_id = 12098; // TODO: should be per-vpn	526	static u16 dns_id = 0; // TODO: should be per-vpn
444		527
445	static u16 next_id ()	528	static u16 next_id ()
446	{	529	{
		530	if (!dns_id)
		531	dns_id = time (0);
		532
447	// the simplest lsfr with periodicity 65535 i could find	533	// the simplest lsfr with periodicity 65535 i could find
448	dns_id = (dns_id << 1)	534	dns_id = (dns_id << 1)
449	\| (((dns_id >> 1)	535	\| (((dns_id >> 1)
450	^ (dns_id >> 2)	536	^ (dns_id >> 2)
451	^ (dns_id >> 4)	537	^ (dns_id >> 4)
452	^ (dns_id >> 15)) & 1);	538	^ (dns_id >> 15)) & 1);
453		539
454	return dns_id;	540	return dns_id;
455	}	541	}
456		542
457	dns_req::dns_req (connection *c)	543	struct dns_rcv;
458	: conn (c)	544	struct dns_snd;
		545
		546	struct dns_connection
459	{	547	{
460	next = 0;	548	connection *c;
		549	struct vpn *vpn;
		550
		551	dns_cfg cfg;
		552
		553	bool established;
		554
		555	tstamp last_received;
		556	tstamp last_sent;
		557	double min_latency;
		558	double poll_interval, send_interval;
		559
		560	vector<dns_rcv *> rcvpq;
		561
		562	byte_stream rcvdq; int rcvseq; int repseq;
		563	byte_stream snddq; int sndseq;
		564
		565	inline void time_cb (ev::timer &w, int revents); ev::timer tw;
		566	void receive_rep (dns_rcv *r);
		567
		568	dns_connection (connection *c);
		569	~dns_connection ();
		570	};
		571
		572	struct dns_snd
		573	{
		574	dns_packet *pkt;
		575	tstamp timeout, sent;
		576	int retry;
		577	struct dns_connection *dns;
		578	int seqno;
		579	bool stdhdr;
		580
		581	void gen_stream_req (int seqno, byte_stream &stream);
		582	void gen_syn_req ();
		583
		584	dns_snd (dns_connection *dns);
		585	~dns_snd ();
		586	};
		587
		588	dns_snd::dns_snd (dns_connection *dns)
		589	: dns (dns)
		590	{
		591	timeout = 0;
461	retry = 0;	592	retry = 0;
		593	seqno = 0;
		594	sent = ev_now ();
		595	stdhdr = false;
462		596
463	pkt = new dns_packet;	597	pkt = new dns_packet;
464		598
465	pkt->id = next_id ();	599	pkt->id = next_id ();
466	}	600	}
467		601
		602	dns_snd::~dns_snd ()
		603	{
		604	delete pkt;
		605	}
		606
		607	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		608	{
		609	// add tunnel domain
		610	for (;;)
		611	{
		612	const char *end = strchr (domain, '.');
		613
		614	if (!end)
		615	end = domain + strlen (domain);
		616
		617	int len = end - domain;
		618
		619	pkt [offs++] = len;
		620	memcpy (pkt.at (offs), domain, len);
		621	offs += len;
		622
		623	if (!*end)
		624	break;
		625
		626	domain = end + 1;
		627	}
		628	}
		629
468	void dns_req::gen_stream_req (int seqno, byte_stream *stream)	630	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
469	{	631	{
		632	stdhdr = true;
470	this->seqno = seqno;	633	this->seqno = seqno;
		634
		635	timeout = ev_now () + INITIAL_TIMEOUT;
471		636
472	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	637	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
473	pkt->qdcount = htons (1);	638	pkt->qdcount = htons (1);
474		639
475	int offs = 6*2;	640	int offs = 6*2;
476	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	641	int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
477	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	642	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
478	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra	643	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
479		644
480	char enc[256], *encp = enc;	645	char enc[256], *encp = enc;
481	encode_header (enc, THISNODE->id, seqno);	646	encode_header (enc, THISNODE->id, seqno);
482		647
483	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);	648	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
484		649
485	if (datalen > stream->size ())	650	if (datalen > stream.size ())
486	datalen = stream->size ();	651	datalen = stream.size ();
487		652
488	int enclen = cdc62.encode (enc + HDRSIZE, stream->begin (), datalen) + HDRSIZE;	653	int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
489
490	printf ("cdc62.encode %d->%d:%02x %02x %02x %02x\n", datalen, enclen,
491	stream->begin ()[0],
492	stream->begin ()[1],
493	stream->begin ()[2],
494	stream->begin ()[3]);
495
496	stream->remove (datalen);	654	stream.remove (datalen);
497		655
498	while (enclen)	656	while (enclen)
499	{	657	{
500	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;	658	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
501		659
…		…
506	encp += lbllen;	664	encp += lbllen;
507		665
508	enclen -= lbllen;	666	enclen -= lbllen;
509	}	667	}
510		668
511	const char *suffix = THISNODE->domain;	669	append_domain (*pkt, offs, dns->c->conf->domain);
512
513	// add tunnel domain
514	for (;;)
515	{
516	const char *end = strchr (suffix, '.');
517
518	if (!end)
519	end = suffix + strlen (suffix);
520
521	int len = end - suffix;
522
523	(*pkt)[offs++] = len;
524	memcpy (&((*pkt)[offs]), suffix, len);
525	offs += len;
526
527	if (!*end)
528	break;
529
530	suffix = end + 1;
531	}
532		670
533	(*pkt)[offs++] = 0;	671	(*pkt)[offs++] = 0;
534	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	672	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		673	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		674
		675	pkt->len = offs;
		676	}
		677
		678	void dns_snd::gen_syn_req ()
		679	{
		680	timeout = ev_now () + INITIAL_SYN_TIMEOUT;
		681
		682	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		683	pkt->qdcount = htons (1);
		684
		685	int offs = 6 * 2;
		686
		687	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
		688
		689	assert (elen <= MAX_LBL_SIZE);
		690
		691	(*pkt)[offs] = elen;
		692	offs += elen + 1;
		693	append_domain (*pkt, offs, dns->c->conf->domain);
		694
		695	(*pkt)[offs++] = 0;
		696	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
535	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	697	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
536		698
537	pkt->len = offs;	699	pkt->len = offs;
538	}	700	}
539		701
…		…
558	{	720	{
559	delete pkt;	721	delete pkt;
560	}	722	}
561		723
562	/////////////////////////////////////////////////////////////////////////////	724	/////////////////////////////////////////////////////////////////////////////
563		725
564	struct dns_cfg	726	dns_connection::dns_connection (connection *c)
		727	: c (c)
		728	, rcvdq (MAX_BACKLOG * 2)
		729	, snddq (MAX_BACKLOG)
565	{	730	{
566	u8 id1, id2, id3;	731	tw.set<dns_connection, &dns_connection::time_cb> (this);
567	u8 def_ttl;
568	u8 unused1;
569	u16 max_size;
570	u8 flags1, flags2;
571	};
572		732
		733	vpn = c->vpn;
		734
		735	established = false;
		736
		737	rcvseq = repseq = sndseq = 0;
		738
		739	last_sent = last_received = 0;
		740	poll_interval = 0.5; // starting here
		741	send_interval = 0.5; // starting rate
		742	min_latency = INITIAL_TIMEOUT;
		743	}
		744
		745	dns_connection::~dns_connection ()
		746	{
		747	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		748	i != rcvpq.end ();
		749	++i)
		750	delete *i;
		751	}
		752
573	void connection::dnsv4_receive_rep (struct dns_rcv *r)	753	void dns_connection::receive_rep (dns_rcv *r)
574	{	754	{
		755	if (r->datalen)
		756	{
		757	last_received = ev_now ();
		758	tw ();
		759
		760	poll_interval = send_interval;
		761	}
		762	else
		763	{
		764	poll_interval *= 1.5;
		765
		766	if (poll_interval > MAX_POLL_INTERVAL)
		767	poll_interval = MAX_POLL_INTERVAL;
		768	}
		769
575	dns_rcvpq.push_back (r);	770	rcvpq.push_back (r);
576		771
577	printf ("%d got inketc %d (%02x %02x %02x %02x)\n", THISNODE->id, r->seqno
578	,r->data[0]
579	,r->data[1]
580	,r->data[2]
581	,r->data[3]
582	);
583	redo:	772	redo:
584		773
585	// find next packet	774	// find next packet
586	for (vector<dns_rcv *>::iterator i = dns_rcvpq.end (); i-- != dns_rcvpq.begin (); )	775	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
587	if (SEQNO_EQ (dns_rcvseq, (*i)->seqno))	776	if (SEQNO_EQ (rcvseq, (*i)->seqno))
588	{	777	{
		778	//printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
589	// enter the packet into our input stream	779	// enter the packet into our input stream
590	r = *i;	780	r = *i;
591		781
592	printf ("%d checking for older packet %d\n", THISNODE->id, dns_rcvseq);
593	// remove the oldest packet, look forward, as it's oldest first	782	// remove the oldest packet, look forward, as it's oldest first
594	for (vector<dns_rcv *>::iterator j = dns_rcvpq.begin (); j != dns_rcvpq.end (); ++j)	783	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
595	if (SEQNO_EQ ((*j)->seqno, dns_rcvseq - MAX_WINDOW))	784	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
596	{	785	{
597	printf ("%d removing %d\n", THISNODE->id, (*j)->seqno);	786	//printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
598	delete *j;	787	delete *j;
599	dns_rcvpq.erase (j);	788	rcvpq.erase (j);
600	break;	789	break;
601	}	790	}
602		791
603	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;	792	rcvseq = (rcvseq + 1) & SEQNO_MASK;
604		793
605	if (!dns_snddq && !dns_rcvdq)	794	if (!rcvdq.put (r->data, r->datalen))
606	{	795	{
607	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);	796	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
608	dns_snddq = new byte_stream (MAX_BACKLOG);	797	abort (); // MUST never overflow, can be caused by data corruption, TODO
609
610	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
611	}	798	}
612		799
613	if (!dns_rcvdq->put (r->data, r->datalen))
614	abort (); // MUST never overflow, can be caused by data corruption, TODO
615
616	while (vpn_packet *pkt = dns_rcvdq->get ())	800	while (vpn_packet *pkt = rcvdq.get ())
617	{	801	{
618	sockinfo si;	802	sockinfo si;
619	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	803	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
620		804
621	vpn->recv_vpn_packet (pkt, si);	805	vpn->recv_vpn_packet (pkt, si);
		806
		807	delete pkt;
622	}	808	}
623		809
624	// check for further packets	810	// check for further packets
625	goto redo;	811	goto redo;
626	}	812	}
627	}	813	}
628		814
629	dns_packet *	815	void
630	vpn::dnsv4_server (dns_packet *pkt)	816	vpn::dnsv4_server (dns_packet &pkt)
631	{	817	{
632	u16 flags = ntohs (pkt->flags);	818	u16 flags = ntohs (pkt.flags);
633		819
634	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
635	int offs = 6 * 2; // skip header	820	int offs = 6 * 2; // skip header
636		821
637	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	822	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
638		823
639	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	824	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
640	&& pkt->qdcount == htons (1))	825	&& pkt.qdcount == htons (1))
641	{	826	{
642	char qname[MAXSIZE];	827	char qname [MAXSIZE];
643	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	828	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
644		829
645	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	830	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
646	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	831	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
647		832
648	pkt->qdcount = htons (1);	833	pkt.qdcount = htons (1);
649	pkt->ancount = 0;	834	pkt.ancount = 0;
650	pkt->nscount = 0; // should be self, as other nameservers reply like this	835	pkt.nscount = 0; // should be self, as other nameservers reply like this
651	pkt->arcount = 0; // a record for self, as other nameservers reply like this	836	pkt.arcount = 0; // a record for self, as other nameservers reply like this
652		837
653	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	838	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
654		839
655	int dlen = strlen (THISNODE->domain);	840	int dlen = strlen (THISNODE->domain);
656		841
657	if (qclass == RR_CLASS_IN	842	if (qclass == RR_CLASS_IN
658	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
659	&& qlen > dlen + 1 + HDRSIZE	843	&& qlen > dlen + 1
660	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	844	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
661	{	845	{
662	// correct class, domain: parse	846	// now generate reply
663	int client, seqno;	847	pkt.ancount = htons (1); // one answer RR
664	decode_header (qname, client, seqno);	848	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
665		849
666	u8 data[MAXSIZE];	850	if ((qtype == RR_TYPE_ANY
667	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	851	\|\| qtype == RR_TYPE_TXT
668		852	\|\| qtype == RR_TYPE_NULL)
669	printf ("cdc62.decode %d(%d): %02x %02x %02x %02x\n",
670	qlen - (dlen + 1 + HDRSIZE), datalen	853	&& qlen > dlen + 1 + HDRSIZE)
671	,data[0]
672	,data[1]
673	,data[2]
674	,data[3]);
675
676	printf ("SRV got %d <%.*s>\n", seqno, qlen, qname + HDRSIZE);//D
677	printf ("SRV got %d <%.*s>\n", seqno, qlen - (dlen + 1 + HDRSIZE), qname + HDRSIZE);//D
678
679	if (0 < client && client <= conns.size ())
680	{	854	{
		855	// correct class, domain: parse
		856	int client, seqno;
		857	decode_header (qname, client, seqno);
		858
		859	u8 data[MAXSIZE];
		860	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
		861
		862	if (0 < client && client <= conns.size ())
		863	{
681	connection *c = conns [client - 1];	864	connection *c = conns [client - 1];
		865	dns_connection *dns = c->dns;
		866	dns_rcv *rcv;
682		867
		868	if (dns)
		869	{
683	for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.end (); i-- != c->dns_rcvpq.begin (); )	870	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
684	if (SEQNO_EQ ((*i)->seqno, seqno))	871	if (SEQNO_EQ ((*i)->seqno, seqno))
		872	{
		873	// already seen that request: simply reply with the cached reply
		874	dns_rcv r = i;
		875
		876	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		877
		878	// refresh header & id, as the retry count could have changed
		879	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		880	r->pkt->id = pkt.id;
		881
		882	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		883
		884	goto duplicate_request;
		885	}
		886
		887	// new packet, queue
		888	rcv = new dns_rcv (seqno, data, datalen);
		889	dns->receive_rep (rcv);
		890	}
		891
685	{	892	{
686	// already seen that request: simply reply with the cached reply	893	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
687	dns_rcv r = i;
688		894
689	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	895	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		896	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		897	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		898	pkt [offs++] = 0; pkt [offs++] = 0;
		899	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
690		900
691	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);	901	int rdlen_offs = offs += 2;
692	pkt->id = r->pkt->id;	902
693	goto duplicate_request;	903	if (dns)
		904	{
		905	int dlen = ntohs (dns->cfg.max_size) - offs;
		906
		907	// bind doesn't compress well, so reduce further by one label length
		908	dlen -= qlen;
		909
		910	// only put data into in-order sequence packets, if
		911	// we receive out-of-order packets we generate empty
		912	// replies
		913	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		914	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
		915	{
		916	dns->repseq = seqno;
		917
		918	while (dlen > 1 && !dns->snddq.empty ())
		919	{
		920	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		921
		922	if (txtlen > dns->snddq.size ())
		923	txtlen = dns->snddq.size ();
		924
		925	pkt[offs++] = txtlen;
		926	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
		927	offs += txtlen;
		928	dns->snddq.remove (txtlen);
		929
		930	dlen -= txtlen + 1;
		931	}
		932	}
		933
		934	// avoid completely empty TXT rdata
		935	if (offs == rdlen_offs)
		936	pkt[offs++] = 0;
		937
		938	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
		939	}
		940	else
		941	{
		942	// send RST
		943	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		944	pkt [offs++] = CMD_IP_RST;
		945	}
		946
		947	int rdlen = offs - rdlen_offs;
		948
		949	pkt [rdlen_offs - 2] = rdlen >> 8;
		950	pkt [rdlen_offs - 1] = rdlen;
		951
		952	if (dns)
		953	{
		954	// now update dns_rcv copy
		955	rcv->pkt->len = offs;
		956	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		957	}
694	}	958	}
695		959
696	// new packet, queue	960	duplicate_request: ;
697	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);	961	}
698	c->dnsv4_receive_rep (rcv);	962	else
699
700	// now generate reply
701	pkt->ancount = htons (1); // one answer RR
702	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	963	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		964	}
		965	else if (qtype == RR_TYPE_A
		966	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		967	{
		968	dns_cfg cfg;
		969	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		970	int client = ntohs (cfg.client);
703		971
704	(*pkt) [offs++] = 0xc0;
705	(pkt) [offs++] = 6 2; // same as in query section	972	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
706		973
707	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;	974	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
708	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;	975	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
709
710	(pkt) [offs++] = 0; (pkt) [offs++] = 0;	976	pkt [offs++] = 0; pkt [offs++] = 0;
711	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL	977	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		978	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
712		979
713	int dlen = MAX_PKT_SIZE - offs - 2;	980	slog (L_INFO, _("DNS: client %d connects"), client);
714		981
715	// bind doesn't compress well, so reduce further by one label length	982	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
716	dlen -= qlen;	983	pkt [offs++] = CMD_IP_REJ;
717		984
718	int rdlen_offs = offs += 2;	985	if (0 < client && client <= conns.size ())
719
720	while (c->dns_snddq
721	&& !c->dns_snddq->empty ()
722	&& dlen > 1)
723	{	986	{
724	int txtlen = dlen <= 255 ? dlen - 1 : 255;	987	connection *c = conns [client - 1];
725		988
726	if (txtlen > c->dns_snddq->size ())	989	if (cfg.valid ())
727	txtlen = c->dns_snddq->size ();	990	{
		991	pkt [offs - 1] = CMD_IP_SYN;
728		992
729	(*pkt)[offs++] = txtlen;	993	delete c->dns;
730	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);	994	c->dns = new dns_connection (c);
731	offs += txtlen;	995	c->dns->cfg = cfg;
732	c->dns_snddq->remove (txtlen);	996	}
733
734	dlen -= txtlen + 1;
735	}	997	}
736
737	// avoid empty TXT rdata
738	if (offs == rdlen_offs)
739	(*pkt)[offs++] = 0;
740
741	int rdlen = offs - rdlen_offs;
742
743	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
744	(*pkt) [rdlen_offs - 1] = rdlen;
745
746	// now update dns_rcv copy
747	rcv->pkt->len = offs;
748	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
749
750	duplicate_request: ;
751	}	998	}
752	else
753	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
754	}	999	}
755		1000
756	pkt->len = offs;	1001	pkt.len = offs;
757	}	1002	}
758
759	return pkt;
760	}	1003	}
761		1004
762	void	1005	void
763	vpn::dnsv4_client (dns_packet *pkt)	1006	vpn::dnsv4_client (dns_packet &pkt)
764	{	1007	{
765	u16 flags = ntohs (pkt->flags);	1008	u16 flags = ntohs (pkt.flags);
766	int offs = 6 * 2; // skip header	1009	int offs = 6 * 2; // skip header
767		1010
768	pkt->qdcount = ntohs (pkt->qdcount);	1011	pkt.qdcount = ntohs (pkt.qdcount);
769	pkt->ancount = ntohs (pkt->ancount);	1012	pkt.ancount = ntohs (pkt.ancount);
770		1013
771	// go through our request list and find the corresponding request	1014	// go through our request list and find the corresponding request
772	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	1015	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
773	i != dns_sndpq.end ();	1016	i != dns_sndpq.end ();
774	++i)	1017	++i)
775	if ((*i)->pkt->id == pkt->id)	1018	if ((*i)->pkt->id == pkt.id)
776	{	1019	{
		1020	dns_connection dns = (i)->dns;
777	connection c = (i)->conn;	1021	connection *c = dns->c;
778	int seqno = (*i)->seqno;	1022	int seqno = (*i)->seqno;
779	u8 data[MAXSIZE], *datap = data;	1023	u8 data[MAXSIZE], *datap = data;
		1024	//printf ("rcv pkt %x\n", seqno);//D
		1025
		1026	if ((*i)->retry)
		1027	{
		1028	dns->send_interval *= 1.01;
		1029	if (dns->send_interval > MAX_SEND_INTERVAL)
		1030	dns->send_interval = MAX_SEND_INTERVAL;
		1031	}
		1032	else
		1033	{
		1034	#if 0
		1035	dns->send_interval *= 0.999;
		1036	#endif
		1037	// the latency surely puts an upper bound on
		1038	// the minimum send interval
		1039	double latency = ev_now () - (*i)->sent;
		1040
		1041	if (latency < dns->min_latency)
		1042	dns->min_latency = latency;
		1043
		1044	if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
		1045	dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
		1046
		1047	if (dns->send_interval < conf.dns_send_interval)
		1048	dns->send_interval = conf.dns_send_interval;
		1049	}
780		1050
781	delete *i;	1051	delete *i;
782	dns_sndpq.erase (i);	1052	dns_sndpq.erase (i);
783		1053
784	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	1054	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
785	{	1055	{
786	char qname[MAXSIZE];	1056	char qname[MAXSIZE];
787		1057
788	while (pkt->qdcount-- && offs < MAXSIZE - 4)	1058	while (pkt.qdcount-- && offs < MAXSIZE - 4)
789	{	1059	{
790	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1060	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
791	offs += 4; // skip qtype, qclass	1061	offs += 4; // skip qtype, qclass
792	}	1062	}
793		1063
794	while (pkt->ancount-- && offs < MAXSIZE - 10)	1064	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
795	{	1065	{
796	int qlen = //D
797	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1066	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
798		1067
799	printf ("got reply to <%.*s>\n", qlen, qname);//D
800
801	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1068	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
802	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1069	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
803	u32 ttl = (*pkt) [offs++] << 24;	1070	u32 ttl = pkt [offs++] << 24;
804	ttl \|= (*pkt) [offs++] << 16;	1071	ttl \|= pkt [offs++] << 16;
805	ttl \|= (*pkt) [offs++] << 8;	1072	ttl \|= pkt [offs++] << 8;
806	ttl \|= (*pkt) [offs++];	1073	ttl \|= pkt [offs++];
807
808	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1074	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
809		1075
810	if (rdlen <= MAXSIZE - offs)	1076	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
811	{	1077	{
812	// decode bytes, finally	1078	if (rdlen <= MAXSIZE - offs)
813
814	while (rdlen)
815	{	1079	{
		1080	// decode bytes, finally
		1081
		1082	while (rdlen)
		1083	{
816	int txtlen = (*pkt) [offs++];	1084	int txtlen = pkt [offs++];
817		1085
818	assert (txtlen + offs < MAXSIZE - 1);	1086	assert (txtlen + offs < MAXSIZE - 1);
819		1087
820	memcpy (datap, pkt->at (offs), txtlen);	1088	memcpy (datap, pkt.at (offs), txtlen);
821	datap += txtlen; offs += txtlen;	1089	datap += txtlen; offs += txtlen;
822		1090
823	rdlen -= txtlen + 1;	1091	rdlen -= txtlen + 1;
		1092	}
824	}	1093	}
825
826	}	1094	}
		1095	else if (qtype == RR_TYPE_A)
		1096	{
		1097	u8 ip [4];
827		1098
		1099	ip [0] = pkt [offs++];
		1100	ip [1] = pkt [offs++];
		1101	ip [2] = pkt [offs++];
		1102	ip [3] = pkt [offs++];
		1103
		1104	if (ip [0] == CMD_IP_1
		1105	&& ip [1] == CMD_IP_2
		1106	&& ip [2] == CMD_IP_3)
		1107	{
		1108	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
		1109
		1110	if (ip [3] == CMD_IP_RST)
		1111	{
		1112	slog (L_DEBUG, _("DNS: got tunnel RST request"));
		1113
		1114	delete dns; c->dns = 0;
		1115
		1116	return;
		1117	}
		1118	else if (ip [3] == CMD_IP_SYN)
		1119	{
		1120	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
		1121	dns->established = true;
		1122	}
		1123	else if (ip [3] == CMD_IP_REJ)
		1124	{
		1125	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1126	abort ();
		1127	}
		1128	else
		1129	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
		1130	}
		1131	else
		1132	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
		1133	ip [0], ip [1], ip [2], ip [3]);
		1134
		1135	return;
		1136	}
		1137
		1138	int client, rseqno;
		1139	decode_header (qname, client, rseqno);
		1140
		1141	if (client != THISNODE->id)
		1142	{
		1143	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
		1144	datap = 0;
		1145	}
		1146	else if (rseqno != seqno)
		1147	{
		1148	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
		1149	datap = 0;
		1150	}
828	}	1151	}
829	}	1152	}
830		1153
831	// todo: pkt now used	1154	// todo: pkt now used
		1155	if (datap)
832	c->dnsv4_receive_rep (new dns_rcv (seqno, data, datap - data));	1156	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
833		1157
834	break;	1158	break;
835	}	1159	}
836
837	delete pkt;
838	}	1160	}
839		1161
840	void	1162	void
841	vpn::dnsv4_ev (io_watcher &w, short revents)	1163	vpn::dnsv4_ev (ev::io &w, int revents)
842	{	1164	{
843	if (revents & EVENT_READ)	1165	if (revents & EV_READ)
844	{	1166	{
845	dns_packet *pkt = new dns_packet;	1167	dns_packet *pkt = new dns_packet;
846	struct sockaddr_in sa;	1168	struct sockaddr_in sa;
847	socklen_t sa_len = sizeof (sa);	1169	socklen_t sa_len = sizeof (sa);
848		1170
849	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1171	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
850		1172
851	if (pkt->len > 0)	1173	if (pkt->len > 0)
852	{	1174	{
853	if (pkt->flags & htons (FLAG_TC))	1175	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1176	dnsv4_client (*pkt);
		1177	else
854	{	1178	{
855	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));	1179	dnsv4_server (*pkt);
856	//TODO connection reset	1180	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
857	}	1181	}
858		1182
859	if (THISNODE->dns_port)	1183	delete pkt;
860	{
861	pkt = dnsv4_server (pkt);
862	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);
863	}
864	else
865	dnsv4_client (pkt);
866	}	1184	}
867	}	1185	}
868	}	1186	}
869		1187
870	bool	1188	bool
871	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1189	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
872	{	1190	{
873	// never initialized	1191	int client = ntohl (si.host);
874	if (!dns_snddq && !dns_rcvdq)
875	{
876	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
877	dns_snddq = new byte_stream (MAX_BACKLOG);
878		1192
879	//dns_rcvseq = dns_sndseq = 0;	1193	assert (0 < client && client <= conns.size ());
880		1194
881	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);	1195	connection *c = conns [client - 1];
882	}	1196
		1197	if (!c->dns)
		1198	c->dns = new dns_connection (c);
883		1199
884	if (!dns_snddq->put (pkt))	1200	if (c->dns->snddq.put (pkt))
885	return false;	1201	c->dns->tw ();
886		1202
887	// start timer if neccessary	1203	// always return true even if the buffer overflows
888	if (!THISNODE->dns_port && !dnsv4_tw.active)
889	dnsv4_cb (dnsv4_tw);
890
891	return true;	1204	return true;
892	}	1205	}
893		1206
894	void	1207	void
895	connection::dnsv4_cb (time_watcher &w)	1208	connection::dnsv4_reset_connection ()
896	{	1209	{
		1210	//delete dns; dns = 0; //TODO
		1211	}
		1212
		1213	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1214
		1215	void
		1216	dns_connection::time_cb (ev::timer &w, int revents)
		1217	{
		1218	// servers have to be polled
		1219	if (THISNODE->dns_port)
		1220	return;
		1221
897	// check for timeouts and (re)transmit	1222	// check for timeouts and (re)transmit
898	tstamp next = NOW + 60;	1223	tstamp next = ev::now () + poll_interval;
899	dns_req *send = 0;	1224	dns_snd *send = 0;
900		1225
901	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1226	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
902	i != vpn->dns_sndpq.end ();	1227	i != vpn->dns_sndpq.end ();
903	++i)	1228	++i)
904	{	1229	{
905	dns_req r = i;	1230	dns_snd r = i;
906		1231
907	if (r->next <= NOW)	1232	if (r->timeout <= ev_now ())
908	{	1233	{
909	if (!send)	1234	if (!send)
910	{	1235	{
911	send = r;	1236	send = r;
912		1237
913	if (r->retry)//D
914	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
915	r->retry++;	1238	r->retry++;
916	r->next = NOW + r->retry;	1239	r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
		1240	//printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
		1241
		1242	// the following code changes the query section a bit, forcing
		1243	// the forwarder to generate a new request
		1244	if (r->stdhdr)
		1245	encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
917	}	1246	}
918	}	1247	}
919		1248	else
920	if (r->next < next)	1249	NEXT (r->timeout);
921	next = r->next;
922	}	1250	}
923		1251
924	if (!send	1252	if (!send)
925	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)
926	{	1253	{
		1254	// generate a new packet, if wise
		1255
		1256	if (!established)
		1257	{
		1258	if (vpn->dns_sndpq.empty ())
		1259	{
927	send = new dns_req (this);	1260	send = new dns_snd (this);
		1261
		1262	cfg.reset (THISNODE->id);
		1263	send->gen_syn_req ();
		1264	}
		1265	}
		1266	else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
		1267	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1268	{
		1269	if (last_sent + send_interval <= ev_now ())
		1270	{
		1271	//printf ("sending data request etc.\n"); //D
		1272	if (!snddq.empty () \|\| last_received + 1. > ev_now ())
		1273	{
		1274	poll_interval = send_interval;
		1275	NEXT (ev_now () + send_interval);
		1276	}
		1277
		1278	send = new dns_snd (this);
928	send->gen_stream_req (dns_sndseq, dns_snddq);	1279	send->gen_stream_req (sndseq, snddq);
		1280	send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
		1281	//printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
		1282
		1283	sndseq = (sndseq + 1) & SEQNO_MASK;
		1284	}
		1285	else
		1286	NEXT (last_sent + send_interval);
		1287	}
		1288
		1289	if (send)
929	vpn->dns_sndpq.push_back (send);	1290	vpn->dns_sndpq.push_back (send);
930
931	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
932	}	1291	}
933
934	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
935		1292
936	if (send)	1293	if (send)
937	{	1294	{
938	dns_packet *pkt = send->pkt;	1295	last_sent = ev_now ();
939		1296	sendto (vpn->dnsv4_fd,
940	next = min_next;	1297	send->pkt->at (0), send->pkt->len, 0,
941		1298	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
942	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0, dns_si.sav4 (), dns_si.salenv4 ());
943	}	1299	}
944	else if (next < min_next)
945	next = min_next;
946		1300
947	w.start (next);	1301	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1302	poll_interval, send_interval, next - ev_now (),
		1303	vpn->dns_sndpq.size (), snddq.size (),
		1304	rcvpq.size ());
		1305
		1306	// TODO: no idea when this happens, but when next < ev_now (), we have a problem
		1307	// doesn't seem to happen anymore
		1308	if (next < ev_now () + 0.001)
		1309	next = ev_now () + 0.1;
		1310
		1311	w.start (next - ev_now ());
948	}	1312	}
949		1313
950	#endif	1314	#endif
951		1315

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs. Revision 1.46 by pcg, Thu Dec 6 00:35:29 2007 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs.
Revision 1.46 by pcg, Thu Dec 6 00:35:29 2007 UTC