[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 1.38 by pcg, Tue Apr 19 04:23:38 2005 UTC

…		…
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. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20	*/	20	*/
21		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.
		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>
…		…
43		48
44	#include "netcompat.h"	49	#include "netcompat.h"
45		50
46	#include "vpn.h"	51	#include "vpn.h"
47		52
48	#define MIN_RETRY 1.	53	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
49	#define MAX_RETRY 60.	54	#define ACTIVITY_INTERVAL 5.
50		55
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	56	#define INITIAL_TIMEOUT 0.1 // retry timeouts
		57	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
		58
		59	#define MAX_SEND_INTERVAL 2. // optimistic?
		60
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	61	#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	62	#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55		63
56	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	64	#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	65	// 240 leaves about 4 bytes of server reply data
58	// every two request byte sless give room for one reply byte	66	// every request byte less give room for two reply bytes
59		67
60	// seqno has 12 bits (3 bytes a 4 bits in the header)
61	#define SEQNO_MASK 0x7fff	68	#define SEQNO_MASK 0x3fff
62	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	69	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
63		70
64	#define MAX_LBL_SIZE 63	71	#define MAX_LBL_SIZE 63
65	#define MAX_PKT_SIZE 512	72	#define MAX_PKT_SIZE 512
66		73
		74	#define RR_TYPE_A 1
		75	#define RR_TYPE_NULL 10
67	#define RR_TYPE_TXT 16	76	#define RR_TYPE_TXT 16
68	#define RR_TYPE_ANY 255	77	#define RR_TYPE_ANY 255
		78
69	#define RR_CLASS_IN 1	79	#define RR_CLASS_IN 1
		80
		81	#define CMD_IP_1 207
		82	#define CMD_IP_2 46
		83	#define CMD_IP_3 236
		84	#define CMD_IP_RST 29
		85	#define CMD_IP_SYN 113
		86	#define CMD_IP_REJ 32
70		87
71	// works for cmaps up to 255 (not 256!)	88	// works for cmaps up to 255 (not 256!)
72	struct charmap	89	struct charmap
73	{	90	{
74	enum { INVALID = (u8)255 };	91	enum { INVALID = (u8)255 };
…		…
154	return dec_len [len];	171	return dec_len [len];
155	}	172	}
156		173
157	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	174	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
158	{	175	{
159	if (!len)	176	if (!len \|\| len > MAX_DEC_LEN)
160	return 0;	177	return 0;
161		178
162	int elen = encode_len (len);	179	int elen = encode_len (len);
163		180
164	mp_limb_t m [MAX_LIMBS];	181	mp_limb_t m [MAX_LIMBS];
…		…
183	return elen;	200	return elen;
184	}	201	}
185		202
186	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	203	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
187	{	204	{
188	if (!len)	205	if (!len \|\| len > MAX_ENC_LEN)
189	return 0;	206	return 0;
190		207
191	u8 src_ [MAX_ENC_LEN];	208	u8 src_ [MAX_ENC_LEN];
192	unsigned int elen = 0;	209	unsigned int elen = 0;
193		210
…		…
240	}	257	}
241	abort ();	258	abort ();
242	}	259	}
243	#endif	260	#endif
244		261
245	// the following sequence has been crafted to	262	//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");	263	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	264	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
252	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	265	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
253	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	266	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
254		267
255	/////////////////////////////////////////////////////////////////////////////	268	/////////////////////////////////////////////////////////////////////////////
256		269
257	#define HDRSIZE 6	270	#define HDRSIZE 6
258		271
259	inline void encode_header (char *data, int clientid, int seqno)	272	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
260	{	273	{
261	u8 hdr[3] = { clientid, seqno >> 8, seqno };	274	seqno &= SEQNO_MASK;
		275
		276	u8 hdr[3] = {
		277	clientid,
		278	(seqno >> 8) \| (retry << 6),
		279	seqno,
		280	};
262		281
263	assert (clientid < 256);	282	assert (clientid < 256);
264		283
265	cdc26.encode (data, hdr, 3);	284	cdc26.encode (data, hdr, 3);
266	}	285	}
…		…
269	{	288	{
270	u8 hdr[3];	289	u8 hdr[3];
271		290
272	cdc26.decode (hdr, data, HDRSIZE);	291	cdc26.decode (hdr, data, HDRSIZE);
273		292
274	printf ("DEC %02x %02x %02x %02x\n", hdr[0], hdr[1], hdr[2], hdr[3]);
275
276	clientid = hdr[0];	293	clientid = hdr[0];
277	seqno = (hdr[1] << 8) \| hdr[2];	294	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
278	}	295	}
279		296
280	/////////////////////////////////////////////////////////////////////////////	297	/////////////////////////////////////////////////////////////////////////////
281		298
282	struct byte_stream	299	struct byte_stream
…		…
311	}	328	}
312		329
313	void byte_stream::remove (int count)	330	void byte_stream::remove (int count)
314	{	331	{
315	if (count > fill)	332	if (count > fill)
316	abort ();	333	assert (count <= fill);
317		334
318	memmove (data, data + count, fill -= count);	335	memmove (data, data + count, fill -= count);
319	}	336	}
320		337
321	bool byte_stream::put (u8 *data, unsigned int datalen)	338	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
334	return false;	351	return false;
335		352
336	data [fill++] = pkt->len >> 8;	353	data [fill++] = pkt->len >> 8;
337	data [fill++] = pkt->len;	354	data [fill++] = pkt->len;
338		355
339	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	356	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
340		357
341	return true;	358	return true;
342	}	359	}
343		360
344	vpn_packet *byte_stream::get ()	361	vpn_packet *byte_stream::get ()
345	{	362	{
		363	unsigned int len;
		364
		365	for (;;)
		366	{
346	int len = (data [0] << 8) \| data [1];	367	len = (data [0] << 8) \| data [1];
347		368
348	if (len > MAXSIZE && fill >= 2)	369	if (len <= MAXSIZE \|\| fill < 2)
349	abort (); // TODO handle this gracefully, connection reset	370	break;
350		371
		372	// TODO: handle this better than skipping, e.g. by reset
		373	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		374	remove (1);
		375	}
		376
351	if (fill < len + 2)	377	if (fill < len + 2)
352	return 0;	378	return 0;
353		379
354	vpn_packet *pkt = new vpn_packet;	380	vpn_packet *pkt = new vpn_packet;
355		381
356	pkt->len = len;	382	pkt->len = len;
357	memcpy (&((*pkt)[0]), data + 2, len);	383	memcpy (pkt->at (0), data + 2, len);
358	remove (len + 2);	384	remove (len + 2);
359		385
360	return pkt;	386	return pkt;
361	}	387	}
362		388
363	/////////////////////////////////////////////////////////////////////////////	389	/////////////////////////////////////////////////////////////////////////////
364		390
365	#define FLAG_QUERY ( 0 << 15)	391	#define FLAG_QUERY ( 0 << 15)
366	#define FLAG_RESPONSE ( 1 << 15)	392	#define FLAG_RESPONSE ( 1 << 15)
367	#define FLAG_OP_MASK (15 << 14)	393	#define FLAG_OP_MASK (15 << 11)
368	#define FLAG_OP_QUERY ( 0 << 11)	394	#define FLAG_OP_QUERY ( 0 << 11)
369	#define FLAG_AA ( 1 << 10)	395	#define FLAG_AA ( 1 << 10)
370	#define FLAG_TC ( 1 << 9)	396	#define FLAG_TC ( 1 << 9)
371	#define FLAG_RD ( 1 << 8)	397	#define FLAG_RD ( 1 << 8)
372	#define FLAG_RA ( 1 << 7)	398	#define FLAG_RA ( 1 << 7)
…		…
379	#define FLAG_RCODE_REFUSED ( 5 << 0)	405	#define FLAG_RCODE_REFUSED ( 5 << 0)
380		406
381	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	407	#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)	408	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
383		409
		410	struct dns_cfg
		411	{
		412	static int next_uid;
		413
		414	u8 id1, id2, id3, id4;
		415
		416	u8 version;
		417	u8 flags;
		418	u8 rrtype;
		419	u8 def_ttl;
		420
		421	u16 client;
		422	u16 uid; // to make request unique
		423
		424	u16 max_size;
		425	u8 seq_cdc;
		426	u8 req_cdc;
		427
		428	u8 rep_cdc;
		429	u8 delay; // time in 0.01s units that the server may delay replying packets
		430	u8 r3, r4;
		431
		432	u8 r5, r6, r7, r8;
		433
		434	void reset (int clientid);
		435	bool valid ();
		436	};
		437
		438	int dns_cfg::next_uid;
		439
		440	void dns_cfg::reset (int clientid)
		441	{
		442	id1 = 'G';
		443	id2 = 'V';
		444	id3 = 'P';
		445	id4 = 'E';
		446
		447	version = 1;
		448
		449	rrtype = RR_TYPE_TXT;
		450	flags = 0;
		451	def_ttl = 0;
		452	seq_cdc = 26;
		453	req_cdc = 62;
		454	rep_cdc = 0;
		455	max_size = htons (MAX_PKT_SIZE);
		456	client = htons (clientid);
		457	uid = next_uid++;
		458	delay = 0;
		459
		460	r3 = r4 = 0;
		461	r4 = r5 = r6 = r7 = 0;
		462	}
		463
		464	bool dns_cfg::valid ()
		465	{
		466	return id1 == 'G'
		467	&& id2 == 'V'
		468	&& id3 == 'P'
		469	&& id4 == 'E'
		470	&& seq_cdc == 26
		471	&& req_cdc == 62
		472	&& rep_cdc == 0
		473	&& version == 1;
		474	}
		475
384	struct dns_packet : net_packet	476	struct dns_packet : net_packet
385	{	477	{
386	u16 id;	478	u16 id;
387	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	479	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
388	u16 qdcount, ancount, nscount, arcount;	480	u16 qdcount, ancount, nscount, arcount;
389		481
390	u8 data[MAXSIZE - 6 * 2];	482	u8 data [MAXSIZE - 6 * 2];
391		483
392	int decode_label (char *data, int size, int &offs);	484	int decode_label (char *data, int size, int &offs);
393	};	485	};
394		486
395	int dns_packet::decode_label (char *data, int size, int &offs)	487	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
426	return data - orig;	518	return data - orig;
427	}	519	}
428		520
429	/////////////////////////////////////////////////////////////////////////////	521	/////////////////////////////////////////////////////////////////////////////
430		522
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	523	static u16 dns_id = 0; // TODO: should be per-vpn
444		524
445	static u16 next_id ()	525	static u16 next_id ()
446	{	526	{
		527	if (!dns_id)
		528	dns_id = time (0);
		529
447	// the simplest lsfr with periodicity 65535 i could find	530	// the simplest lsfr with periodicity 65535 i could find
448	dns_id = (dns_id << 1)	531	dns_id = (dns_id << 1)
449	\| (((dns_id >> 1)	532	\| (((dns_id >> 1)
450	^ (dns_id >> 2)	533	^ (dns_id >> 2)
451	^ (dns_id >> 4)	534	^ (dns_id >> 4)
452	^ (dns_id >> 15)) & 1);	535	^ (dns_id >> 15)) & 1);
453		536
454	return dns_id;	537	return dns_id;
455	}	538	}
456		539
457	dns_req::dns_req (connection *c)	540	struct dns_rcv;
458	: conn (c)	541	struct dns_snd;
		542
		543	struct dns_connection
459	{	544	{
460	next = 0;	545	connection *c;
		546	struct vpn *vpn;
		547
		548	dns_cfg cfg;
		549
		550	bool established;
		551
		552	tstamp last_received;
		553	tstamp last_sent;
		554	double min_latency;
		555	double poll_interval, send_interval;
		556
		557	vector<dns_rcv *> rcvpq;
		558
		559	byte_stream rcvdq; int rcvseq; int repseq;
		560	byte_stream snddq; int sndseq;
		561
		562	void time_cb (time_watcher &w); time_watcher tw;
		563	void receive_rep (dns_rcv *r);
		564
		565	dns_connection (connection *c);
		566	~dns_connection ();
		567	};
		568
		569	struct dns_snd
		570	{
		571	dns_packet *pkt;
		572	tstamp timeout, sent;
		573	int retry;
		574	struct dns_connection *dns;
		575	int seqno;
		576	bool stdhdr;
		577
		578	void gen_stream_req (int seqno, byte_stream &stream);
		579	void gen_syn_req ();
		580
		581	dns_snd (dns_connection *dns);
		582	~dns_snd ();
		583	};
		584
		585	dns_snd::dns_snd (dns_connection *dns)
		586	: dns (dns)
		587	{
		588	timeout = 0;
461	retry = 0;	589	retry = 0;
		590	seqno = 0;
		591	sent = NOW;
		592	stdhdr = false;
462		593
463	pkt = new dns_packet;	594	pkt = new dns_packet;
464		595
465	pkt->id = next_id ();	596	pkt->id = next_id ();
466	}	597	}
467		598
		599	dns_snd::~dns_snd ()
		600	{
		601	delete pkt;
		602	}
		603
		604	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		605	{
		606	// add tunnel domain
		607	for (;;)
		608	{
		609	const char *end = strchr (domain, '.');
		610
		611	if (!end)
		612	end = domain + strlen (domain);
		613
		614	int len = end - domain;
		615
		616	pkt [offs++] = len;
		617	memcpy (pkt.at (offs), domain, len);
		618	offs += len;
		619
		620	if (!*end)
		621	break;
		622
		623	domain = end + 1;
		624	}
		625	}
		626
468	void dns_req::gen_stream_req (int seqno, byte_stream *stream)	627	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
469	{	628	{
		629	stdhdr = true;
470	this->seqno = seqno;	630	this->seqno = seqno;
		631
		632	timeout = NOW + INITIAL_TIMEOUT;
471		633
472	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	634	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
473	pkt->qdcount = htons (1);	635	pkt->qdcount = htons (1);
474		636
475	int offs = 6*2;	637	int offs = 6*2;
476	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	638	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,	639	// 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	640	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
479		641
480	char enc[256], *encp = enc;	642	char enc[256], *encp = enc;
481	encode_header (enc, THISNODE->id, seqno);	643	encode_header (enc, THISNODE->id, seqno);
482		644
483	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);	645	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
484		646
485	if (datalen > stream->size ())	647	if (datalen > stream.size ())
486	datalen = stream->size ();	648	datalen = stream.size ();
487		649
488	int enclen = cdc62.encode (enc + HDRSIZE, stream->begin (), datalen) + HDRSIZE;	650	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);	651	stream.remove (datalen);
497		652
498	while (enclen)	653	while (enclen)
499	{	654	{
500	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;	655	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
501		656
…		…
506	encp += lbllen;	661	encp += lbllen;
507		662
508	enclen -= lbllen;	663	enclen -= lbllen;
509	}	664	}
510		665
511	const char *suffix = THISNODE->domain;	666	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		667
533	(*pkt)[offs++] = 0;	668	(*pkt)[offs++] = 0;
534	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	669	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		670	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		671
		672	pkt->len = offs;
		673	}
		674
		675	void dns_snd::gen_syn_req ()
		676	{
		677	timeout = NOW + INITIAL_SYN_TIMEOUT;
		678
		679	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		680	pkt->qdcount = htons (1);
		681
		682	int offs = 6 * 2;
		683
		684	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
		685
		686	assert (elen <= MAX_LBL_SIZE);
		687
		688	(*pkt)[offs] = elen;
		689	offs += elen + 1;
		690	append_domain (*pkt, offs, dns->c->conf->domain);
		691
		692	(*pkt)[offs++] = 0;
		693	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
535	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	694	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
536		695
537	pkt->len = offs;	696	pkt->len = offs;
538	}	697	}
539		698
…		…
558	{	717	{
559	delete pkt;	718	delete pkt;
560	}	719	}
561		720
562	/////////////////////////////////////////////////////////////////////////////	721	/////////////////////////////////////////////////////////////////////////////
563		722
564	struct dns_cfg	723	dns_connection::dns_connection (connection *c)
		724	: c (c)
		725	, rcvdq (MAX_BACKLOG * 2)
		726	, snddq (MAX_BACKLOG)
		727	, tw (this, &dns_connection::time_cb)
565	{	728	{
566	u8 id1, id2, id3;	729	vpn = c->vpn;
567	u8 def_ttl;
568	u8 unused1;
569	u16 max_size;
570	u8 flags1, flags2;
571	};
572		730
		731	established = false;
		732
		733	rcvseq = repseq = sndseq = 0;
		734
		735	last_sent = last_received = 0;
		736	poll_interval = 0.5; // starting here
		737	send_interval = 0.5; // starting rate
		738	min_latency = INITIAL_TIMEOUT;
		739	}
		740
		741	dns_connection::~dns_connection ()
		742	{
		743	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		744	i != rcvpq.end ();
		745	++i)
		746	delete *i;
		747	}
		748
573	void connection::dnsv4_receive_rep (struct dns_rcv *r)	749	void dns_connection::receive_rep (dns_rcv *r)
574	{	750	{
		751	if (r->datalen)
		752	{
		753	last_received = NOW;
		754	tw.trigger ();
		755
		756	poll_interval = send_interval;
		757	}
		758	else
		759	{
		760	poll_interval *= 1.5;
		761
		762	if (poll_interval > MAX_POLL_INTERVAL)
		763	poll_interval = MAX_POLL_INTERVAL;
		764	}
		765
575	dns_rcvpq.push_back (r);	766	rcvpq.push_back (r);
576		767
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:	768	redo:
584		769
585	// find next packet	770	// find next packet
586	for (vector<dns_rcv *>::iterator i = dns_rcvpq.end (); i-- != dns_rcvpq.begin (); )	771	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
587	if (SEQNO_EQ (dns_rcvseq, (*i)->seqno))	772	if (SEQNO_EQ (rcvseq, (*i)->seqno))
588	{	773	{
589	// enter the packet into our input stream	774	// enter the packet into our input stream
590	r = *i;	775	r = *i;
591		776
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	777	// 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)	778	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
595	if (SEQNO_EQ ((*j)->seqno, dns_rcvseq - MAX_WINDOW))	779	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
596	{	780	{
597	printf ("%d removing %d\n", THISNODE->id, (*j)->seqno);
598	delete *j;	781	delete *j;
599	dns_rcvpq.erase (j);	782	rcvpq.erase (j);
600	break;	783	break;
601	}	784	}
602		785
603	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;	786	rcvseq = (rcvseq + 1) & SEQNO_MASK;
604		787
605	if (!dns_snddq && !dns_rcvdq)	788	if (!rcvdq.put (r->data, r->datalen))
606	{	789	{
607	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);	790	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
608	dns_snddq = new byte_stream (MAX_BACKLOG);	791	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	}	792	}
612		793
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 ())	794	while (vpn_packet *pkt = rcvdq.get ())
617	{	795	{
618	sockinfo si;	796	sockinfo si;
619	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	797	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
620		798
621	vpn->recv_vpn_packet (pkt, si);	799	vpn->recv_vpn_packet (pkt, si);
		800
		801	delete pkt;
622	}	802	}
623		803
624	// check for further packets	804	// check for further packets
625	goto redo;	805	goto redo;
626	}	806	}
627	}	807	}
628		808
629	dns_packet *	809	void
630	vpn::dnsv4_server (dns_packet *pkt)	810	vpn::dnsv4_server (dns_packet &pkt)
631	{	811	{
632	u16 flags = ntohs (pkt->flags);	812	u16 flags = ntohs (pkt.flags);
633		813
634	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
635	int offs = 6 * 2; // skip header	814	int offs = 6 * 2; // skip header
636		815
637	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	816	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
638		817
639	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	818	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
640	&& pkt->qdcount == htons (1))	819	&& pkt.qdcount == htons (1))
641	{	820	{
642	char qname[MAXSIZE];	821	char qname [MAXSIZE];
643	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	822	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
644		823
645	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	824	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
646	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	825	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
647		826
648	pkt->qdcount = htons (1);	827	pkt.qdcount = htons (1);
649	pkt->ancount = 0;	828	pkt.ancount = 0;
650	pkt->nscount = 0; // should be self, as other nameservers reply like this	829	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	830	pkt.arcount = 0; // a record for self, as other nameservers reply like this
652		831
653	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	832	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
654		833
655	int dlen = strlen (THISNODE->domain);	834	int dlen = strlen (THISNODE->domain);
656		835
657	if (qclass == RR_CLASS_IN	836	if (qclass == RR_CLASS_IN
658	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
659	&& qlen > dlen + 1 + HDRSIZE	837	&& qlen > dlen + 1
660	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	838	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
661	{	839	{
662	// correct class, domain: parse	840	// now generate reply
663	int client, seqno;	841	pkt.ancount = htons (1); // one answer RR
664	decode_header (qname, client, seqno);	842	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
665		843
666	u8 data[MAXSIZE];	844	if ((qtype == RR_TYPE_ANY
667	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	845	\|\| qtype == RR_TYPE_TXT
668		846	\|\| qtype == RR_TYPE_NULL)
669	printf ("cdc62.decode %d(%d): %02x %02x %02x %02x\n",
670	qlen - (dlen + 1 + HDRSIZE), datalen	847	&& 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	{	848	{
		849	// correct class, domain: parse
		850	int client, seqno;
		851	decode_header (qname, client, seqno);
		852
		853	u8 data[MAXSIZE];
		854	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
		855
		856	if (0 < client && client <= conns.size ())
		857	{
681	connection *c = conns [client - 1];	858	connection *c = conns [client - 1];
		859	dns_connection *dns = c->dns;
		860	dns_rcv *rcv;
682		861
		862	if (dns)
		863	{
683	for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.end (); i-- != c->dns_rcvpq.begin (); )	864	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
684	if (SEQNO_EQ ((*i)->seqno, seqno))	865	if (SEQNO_EQ ((*i)->seqno, seqno))
		866	{
		867	// already seen that request: simply reply with the cached reply
		868	dns_rcv r = i;
		869
		870	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		871
		872	// refresh header & id, as the retry count could have changed
		873	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		874	r->pkt->id = pkt.id;
		875
		876	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		877
		878	goto duplicate_request;
		879	}
		880
		881	// new packet, queue
		882	rcv = new dns_rcv (seqno, data, datalen);
		883	dns->receive_rep (rcv);
		884	}
		885
685	{	886	{
686	// already seen that request: simply reply with the cached reply	887	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
687	dns_rcv r = i;
688		888
689	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	889	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		890	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		891	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		892	pkt [offs++] = 0; pkt [offs++] = 0;
		893	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
690		894
691	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);	895	int rdlen_offs = offs += 2;
692	pkt->id = r->pkt->id;	896
693	goto duplicate_request;	897	if (dns)
		898	{
		899	int dlen = ntohs (dns->cfg.max_size) - offs;
		900
		901	// bind doesn't compress well, so reduce further by one label length
		902	dlen -= qlen;
		903
		904	// only put data into in-order sequence packets, if
		905	// we receive out-of-order packets we generate empty
		906	// replies
		907	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		908	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
		909	{
		910	dns->repseq = seqno;
		911
		912	while (dlen > 1 && !dns->snddq.empty ())
		913	{
		914	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		915
		916	if (txtlen > dns->snddq.size ())
		917	txtlen = dns->snddq.size ();
		918
		919	pkt[offs++] = txtlen;
		920	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
		921	offs += txtlen;
		922	dns->snddq.remove (txtlen);
		923
		924	dlen -= txtlen + 1;
		925	}
		926	}
		927
		928	// avoid completely empty TXT rdata
		929	if (offs == rdlen_offs)
		930	pkt[offs++] = 0;
		931
		932	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
		933	}
		934	else
		935	{
		936	// send RST
		937	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		938	pkt [offs++] = CMD_IP_RST;
		939	}
		940
		941	int rdlen = offs - rdlen_offs;
		942
		943	pkt [rdlen_offs - 2] = rdlen >> 8;
		944	pkt [rdlen_offs - 1] = rdlen;
		945
		946	if (dns)
		947	{
		948	// now update dns_rcv copy
		949	rcv->pkt->len = offs;
		950	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		951	}
694	}	952	}
695		953
696	// new packet, queue	954	duplicate_request: ;
697	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);	955	}
698	c->dnsv4_receive_rep (rcv);	956	else
699
700	// now generate reply
701	pkt->ancount = htons (1); // one answer RR
702	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	957	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		958	}
		959	else if (qtype == RR_TYPE_A
		960	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		961	{
		962	dns_cfg cfg;
		963	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		964	int client = ntohs (cfg.client);
703		965
704	(*pkt) [offs++] = 0xc0;
705	(pkt) [offs++] = 6 2; // same as in query section	966	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
706		967
707	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;	968	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
708	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;	969	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
709
710	(pkt) [offs++] = 0; (pkt) [offs++] = 0;	970	pkt [offs++] = 0; pkt [offs++] = 0;
711	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL	971	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		972	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
712		973
713	int dlen = MAX_PKT_SIZE - offs - 2;	974	slog (L_INFO, _("DNS: client %d connects"), client);
714		975
715	// bind doesn't compress well, so reduce further by one label length	976	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
716	dlen -= qlen;	977	pkt [offs++] = CMD_IP_REJ;
717		978
718	int rdlen_offs = offs += 2;	979	if (0 < client && client <= conns.size ())
719
720	while (c->dns_snddq
721	&& !c->dns_snddq->empty ()
722	&& dlen > 1)
723	{	980	{
724	int txtlen = dlen <= 255 ? dlen - 1 : 255;	981	connection *c = conns [client - 1];
725		982
726	if (txtlen > c->dns_snddq->size ())	983	if (cfg.valid ())
727	txtlen = c->dns_snddq->size ();	984	{
		985	pkt [offs - 1] = CMD_IP_SYN;
728		986
729	(*pkt)[offs++] = txtlen;	987	delete c->dns;
730	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);	988	c->dns = new dns_connection (c);
731	offs += txtlen;	989	c->dns->cfg = cfg;
732	c->dns_snddq->remove (txtlen);	990	}
733
734	dlen -= txtlen + 1;
735	}	991	}
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	}	992	}
752	else
753	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
754	}	993	}
755		994
756	pkt->len = offs;	995	pkt.len = offs;
757	}	996	}
758
759	return pkt;
760	}	997	}
761		998
762	void	999	void
763	vpn::dnsv4_client (dns_packet *pkt)	1000	vpn::dnsv4_client (dns_packet &pkt)
764	{	1001	{
765	u16 flags = ntohs (pkt->flags);	1002	u16 flags = ntohs (pkt.flags);
766	int offs = 6 * 2; // skip header	1003	int offs = 6 * 2; // skip header
767		1004
768	pkt->qdcount = ntohs (pkt->qdcount);	1005	pkt.qdcount = ntohs (pkt.qdcount);
769	pkt->ancount = ntohs (pkt->ancount);	1006	pkt.ancount = ntohs (pkt.ancount);
770		1007
771	// go through our request list and find the corresponding request	1008	// go through our request list and find the corresponding request
772	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	1009	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
773	i != dns_sndpq.end ();	1010	i != dns_sndpq.end ();
774	++i)	1011	++i)
775	if ((*i)->pkt->id == pkt->id)	1012	if ((*i)->pkt->id == pkt.id)
776	{	1013	{
		1014	dns_connection dns = (i)->dns;
777	connection c = (i)->conn;	1015	connection *c = dns->c;
778	int seqno = (*i)->seqno;	1016	int seqno = (*i)->seqno;
779	u8 data[MAXSIZE], *datap = data;	1017	u8 data[MAXSIZE], *datap = data;
780		1018
		1019	if ((*i)->retry)
		1020	{
		1021	dns->send_interval *= 1.01;
		1022	if (dns->send_interval > MAX_SEND_INTERVAL)
		1023	dns->send_interval = MAX_SEND_INTERVAL;
		1024	}
		1025	else
		1026	{
		1027	#if 0
		1028	dns->send_interval *= 0.999;
		1029	#endif
		1030	// the latency surely puts an upper bound on
		1031	// the minimum send interval
		1032	double latency = NOW - (*i)->sent;
		1033
		1034	if (latency < dns->min_latency)
		1035	dns->min_latency = latency;
		1036
		1037	if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
		1038	dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
		1039
		1040	if (dns->send_interval < conf.dns_send_interval)
		1041	dns->send_interval = conf.dns_send_interval;
		1042	}
		1043
781	delete *i;	1044	delete *i;
782	dns_sndpq.erase (i);	1045	dns_sndpq.erase (i);
783		1046
784	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	1047	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
785	{	1048	{
786	char qname[MAXSIZE];	1049	char qname[MAXSIZE];
787		1050
788	while (pkt->qdcount-- && offs < MAXSIZE - 4)	1051	while (pkt.qdcount-- && offs < MAXSIZE - 4)
789	{	1052	{
790	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1053	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
791	offs += 4; // skip qtype, qclass	1054	offs += 4; // skip qtype, qclass
792	}	1055	}
793		1056
794	while (pkt->ancount-- && offs < MAXSIZE - 10)	1057	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
795	{	1058	{
796	int qlen = //D
797	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1059	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
798		1060
799	printf ("got reply to <%.*s>\n", qlen, qname);//D
800
801	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1061	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
802	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1062	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
803	u32 ttl = (*pkt) [offs++] << 24;	1063	u32 ttl = pkt [offs++] << 24;
804	ttl \|= (*pkt) [offs++] << 16;	1064	ttl \|= pkt [offs++] << 16;
805	ttl \|= (*pkt) [offs++] << 8;	1065	ttl \|= pkt [offs++] << 8;
806	ttl \|= (*pkt) [offs++];	1066	ttl \|= pkt [offs++];
807
808	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1067	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
809		1068
810	if (rdlen <= MAXSIZE - offs)	1069	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
811	{	1070	{
812	// decode bytes, finally	1071	if (rdlen <= MAXSIZE - offs)
813
814	while (rdlen)
815	{	1072	{
		1073	// decode bytes, finally
		1074
		1075	while (rdlen)
		1076	{
816	int txtlen = (*pkt) [offs++];	1077	int txtlen = pkt [offs++];
817		1078
818	assert (txtlen + offs < MAXSIZE - 1);	1079	assert (txtlen + offs < MAXSIZE - 1);
819		1080
820	memcpy (datap, pkt->at (offs), txtlen);	1081	memcpy (datap, pkt.at (offs), txtlen);
821	datap += txtlen; offs += txtlen;	1082	datap += txtlen; offs += txtlen;
822		1083
823	rdlen -= txtlen + 1;	1084	rdlen -= txtlen + 1;
		1085	}
824	}	1086	}
825
826	}	1087	}
		1088	else if (qtype == RR_TYPE_A)
		1089	{
		1090	u8 ip [4];
827		1091
		1092	ip [0] = pkt [offs++];
		1093	ip [1] = pkt [offs++];
		1094	ip [2] = pkt [offs++];
		1095	ip [3] = pkt [offs++];
		1096
		1097	if (ip [0] == CMD_IP_1
		1098	&& ip [1] == CMD_IP_2
		1099	&& ip [2] == CMD_IP_3)
		1100	{
		1101	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
		1102
		1103	if (ip [3] == CMD_IP_RST)
		1104	{
		1105	slog (L_DEBUG, _("DNS: got tunnel RST request"));
		1106
		1107	delete dns; c->dns = 0;
		1108
		1109	return;
		1110	}
		1111	else if (ip [3] == CMD_IP_SYN)
		1112	{
		1113	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
		1114	dns->established = true;
		1115	}
		1116	else if (ip [3] == CMD_IP_REJ)
		1117	{
		1118	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1119	abort ();
		1120	}
		1121	else
		1122	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
		1123	}
		1124	else
		1125	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
		1126	ip [0], ip [1], ip [2], ip [3]);
		1127
		1128	return;
		1129	}
		1130
		1131	int client, rseqno;
		1132	decode_header (qname, client, rseqno);
		1133
		1134	if (client != THISNODE->id)
		1135	{
		1136	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
		1137	datap = 0;
		1138	}
		1139	else if (rseqno != seqno)
		1140	{
		1141	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
		1142	datap = 0;
		1143	}
828	}	1144	}
829	}	1145	}
830		1146
831	// todo: pkt now used	1147	// todo: pkt now used
		1148	if (datap)
832	c->dnsv4_receive_rep (new dns_rcv (seqno, data, datap - data));	1149	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
833		1150
834	break;	1151	break;
835	}	1152	}
836
837	delete pkt;
838	}	1153	}
839		1154
840	void	1155	void
841	vpn::dnsv4_ev (io_watcher &w, short revents)	1156	vpn::dnsv4_ev (io_watcher &w, short revents)
842	{	1157	{
…		…
844	{	1159	{
845	dns_packet *pkt = new dns_packet;	1160	dns_packet *pkt = new dns_packet;
846	struct sockaddr_in sa;	1161	struct sockaddr_in sa;
847	socklen_t sa_len = sizeof (sa);	1162	socklen_t sa_len = sizeof (sa);
848		1163
849	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1164	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
850		1165
851	if (pkt->len > 0)	1166	if (pkt->len > 0)
852	{	1167	{
853	if (pkt->flags & htons (FLAG_TC))	1168	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1169	dnsv4_client (*pkt);
		1170	else
854	{	1171	{
855	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));	1172	dnsv4_server (*pkt);
856	//TODO connection reset	1173	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
857	}	1174	}
858		1175
859	if (THISNODE->dns_port)	1176	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	}	1177	}
867	}	1178	}
868	}	1179	}
869		1180
870	bool	1181	bool
871	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1182	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
872	{	1183	{
873	// never initialized	1184	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		1185
879	//dns_rcvseq = dns_sndseq = 0;	1186	assert (0 < client && client <= conns.size ());
880		1187
881	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);	1188	connection *c = conns [client - 1];
882	}	1189
		1190	if (!c->dns)
		1191	c->dns = new dns_connection (c);
883		1192
884	if (!dns_snddq->put (pkt))	1193	if (c->dns->snddq.put (pkt))
885	return false;	1194	c->dns->tw.trigger ();
886		1195
887	// start timer if neccessary	1196	// 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;	1197	return true;
892	}	1198	}
893		1199
894	void	1200	void
		1201	connection::dnsv4_reset_connection ()
		1202	{
		1203	//delete dns; dns = 0; //TODO
		1204	}
		1205
		1206	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1207
		1208	void
895	connection::dnsv4_cb (time_watcher &w)	1209	dns_connection::time_cb (time_watcher &w)
896	{	1210	{
		1211	// servers have to be polled
		1212	if (THISNODE->dns_port)
		1213	return;
		1214
897	// check for timeouts and (re)transmit	1215	// check for timeouts and (re)transmit
898	tstamp next = NOW + 60;	1216	tstamp next = NOW + poll_interval;
899	dns_req *send = 0;	1217	dns_snd *send = 0;
900		1218
901	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1219	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
902	i != vpn->dns_sndpq.end ();	1220	i != vpn->dns_sndpq.end ();
903	++i)	1221	++i)
904	{	1222	{
905	dns_req r = i;	1223	dns_snd r = i;
906		1224
907	if (r->next <= NOW)	1225	if (r->timeout <= NOW)
908	{	1226	{
909	if (!send)	1227	if (!send)
910	{	1228	{
911	send = r;	1229	send = r;
912		1230
913	if (r->retry)//D
914	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
915	r->retry++;	1231	r->retry++;
916	r->next = NOW + r->retry;	1232	r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor);
		1233
		1234	// the following code changes the query section a bit, forcing
		1235	// the forwarder to generate a new request
		1236	if (r->stdhdr)
		1237	{
		1238	//printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
		1239	//encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
		1240	}
917	}	1241	}
918	}	1242	}
919		1243	else
920	if (r->next < next)	1244	NEXT (r->timeout);
921	next = r->next;
922	}	1245	}
923		1246
924	if (!send	1247	if (!send)
925	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)
926	{	1248	{
		1249	// generate a new packet, if wise
		1250
		1251	if (!established)
		1252	{
		1253	if (vpn->dns_sndpq.empty ())
		1254	{
927	send = new dns_req (this);	1255	send = new dns_snd (this);
		1256
		1257	cfg.reset (THISNODE->id);
		1258	send->gen_syn_req ();
		1259	}
		1260	}
		1261	else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
		1262	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1263	{
		1264	if (last_sent + send_interval <= NOW)
		1265	{
		1266	//printf ("sending data request etc.\n"); //D
		1267	if (!snddq.empty () \|\| last_received + 1. > NOW)
		1268	{
		1269	poll_interval = send_interval;
		1270	NEXT (NOW + send_interval);
		1271	}
		1272
		1273	send = new dns_snd (this);
928	send->gen_stream_req (dns_sndseq, dns_snddq);	1274	send->gen_stream_req (sndseq, snddq);
		1275	send->timeout = NOW + min_latency * conf.dns_timeout_factor;
		1276
		1277	sndseq = (sndseq + 1) & SEQNO_MASK;
		1278	}
		1279	else
		1280	NEXT (last_sent + send_interval);
		1281	}
		1282
		1283	if (send)
929	vpn->dns_sndpq.push_back (send);	1284	vpn->dns_sndpq.push_back (send);
930
931	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
932	}	1285	}
933
934	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
935		1286
936	if (send)	1287	if (send)
937	{	1288	{
938	dns_packet *pkt = send->pkt;	1289	last_sent = NOW;
939		1290	sendto (vpn->dnsv4_fd,
940	next = min_next;	1291	send->pkt->at (0), send->pkt->len, 0,
941		1292	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	}	1293	}
944	else if (next < min_next)	1294
945	next = min_next;	1295	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1296	poll_interval, send_interval, next - NOW,
		1297	vpn->dns_sndpq.size (), snddq.size (),
		1298	rcvpq.size ());
		1299
		1300	// TODO: no idea when this happens, but when next < NOW, we have a problem
		1301	// doesn't seem to happen anymore
		1302	if (next < NOW + 0.001)
		1303	next = NOW + 0.1;
946		1304
947	w.start (next);	1305	w.start (next);
948	}	1306	}
949		1307
950	#endif	1308	#endif

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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 1.38 by pcg, Tue Apr 19 04:23:38 2005 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 1.38 by pcg, Tue Apr 19 04:23:38 2005 UTC