[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 1.30 by pcg, Mon Mar 14 17:40:01 2005 UTC

…		…
25		25
26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.	26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27	// it's a hack, use only in emergency situations please.	27	// it's a hack, use only in emergency situations please.
28		28
29	#include <cstring>	29	#include <cstring>
		30	#include <cassert>
30		31
31	#include <sys/types.h>	32	#include <sys/types.h>
32	#include <sys/socket.h>	33	#include <sys/socket.h>
33	#include <sys/wait.h>	34	#include <sys/wait.h>
34	#include <sys/uio.h>	35	#include <sys/uio.h>
…		…
43		44
44	#include "netcompat.h"	45	#include "netcompat.h"
45		46
46	#include "vpn.h"	47	#include "vpn.h"
47		48
48	#define MIN_RETRY 1.	49	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
49	#define MAX_RETRY 60.	50	#define ACTIVITY_INTERVAL 5.
50		51
		52	#define INITIAL_TIMEOUT 0.1 // retry timeouts
		53	#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn
		54
		55	#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
		56	#define MAX_SEND_INTERVAL 2. // optimistic?
		57
		58	#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	59	#define MAX_OUTSTANDING 2 // max. outstanding requests
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	60	#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	61	#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55		62
56	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	63	#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	64	// 240 leaves about 4 bytes of server reply data
58	// every two request byte sless give room for one reply byte	65	// every two request bytes less give room for one reply byte
59		66
60	// seqno has 12 bits (3 bytes a 4 bits in the header)
61	#define SEQNO_MASK 0x7fff	67	#define SEQNO_MASK 0x3fff
62	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	68	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
63		69
64	#define MAX_LBL_SIZE 63	70	#define MAX_LBL_SIZE 63
65	#define MAX_PKT_SIZE 512	71	#define MAX_PKT_SIZE 512
66		72
		73	#define RR_TYPE_A 1
		74	#define RR_TYPE_NULL 10
67	#define RR_TYPE_TXT 16	75	#define RR_TYPE_TXT 16
68	#define RR_TYPE_ANY 255	76	#define RR_TYPE_ANY 255
		77
69	#define RR_CLASS_IN 1	78	#define RR_CLASS_IN 1
		79
		80	#define CMD_IP_1 207
		81	#define CMD_IP_2 46
		82	#define CMD_IP_3 236
		83	#define CMD_IP_RST 29
		84	#define CMD_IP_SYN 113
		85	#define CMD_IP_REJ 32
70		86
71	// works for cmaps up to 255 (not 256!)	87	// works for cmaps up to 255 (not 256!)
72	struct charmap	88	struct charmap
73	{	89	{
74	enum { INVALID = (u8)255 };	90	enum { INVALID = (u8)255 };
…		…
154	return dec_len [len];	170	return dec_len [len];
155	}	171	}
156		172
157	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	173	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
158	{	174	{
159	if (!len)	175	if (!len \|\| len > MAX_DEC_LEN)
160	return 0;	176	return 0;
161		177
162	int elen = encode_len (len);	178	int elen = encode_len (len);
163		179
164	mp_limb_t m [MAX_LIMBS];	180	mp_limb_t m [MAX_LIMBS];
…		…
183	return elen;	199	return elen;
184	}	200	}
185		201
186	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	202	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
187	{	203	{
188	if (!len)	204	if (!len \|\| len > MAX_ENC_LEN)
189	return 0;	205	return 0;
190		206
191	u8 src_ [MAX_ENC_LEN];	207	u8 src_ [MAX_ENC_LEN];
192	unsigned int elen = 0;	208	unsigned int elen = 0;
193		209
…		…
240	}	256	}
241	abort ();	257	abort ();
242	}	258	}
243	#endif	259	#endif
244		260
245	// the following sequence has been crafted to	261	//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");	262	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	263	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
252	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	264	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
253	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	265	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
254		266
255	/////////////////////////////////////////////////////////////////////////////	267	/////////////////////////////////////////////////////////////////////////////
256		268
257	#define HDRSIZE 6	269	#define HDRSIZE 6
258		270
259	inline void encode_header (char *data, int clientid, int seqno)	271	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
260	{	272	{
261	u8 hdr[3] = { clientid, seqno >> 8, seqno };	273	seqno &= SEQNO_MASK;
		274
		275	u8 hdr[3] = {
		276	clientid,
		277	(seqno >> 8) \| (retry << 6),
		278	seqno,
		279	};
262		280
263	assert (clientid < 256);	281	assert (clientid < 256);
264		282
265	cdc26.encode (data, hdr, 3);	283	cdc26.encode (data, hdr, 3);
266	}	284	}
…		…
269	{	287	{
270	u8 hdr[3];	288	u8 hdr[3];
271		289
272	cdc26.decode (hdr, data, HDRSIZE);	290	cdc26.decode (hdr, data, HDRSIZE);
273		291
274	printf ("DEC %02x %02x %02x %02x\n", hdr[0], hdr[1], hdr[2], hdr[3]);
275
276	clientid = hdr[0];	292	clientid = hdr[0];
277	seqno = (hdr[1] << 8) \| hdr[2];	293	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
278	}	294	}
279		295
280	/////////////////////////////////////////////////////////////////////////////	296	/////////////////////////////////////////////////////////////////////////////
281		297
282	struct byte_stream	298	struct byte_stream
…		…
311	}	327	}
312		328
313	void byte_stream::remove (int count)	329	void byte_stream::remove (int count)
314	{	330	{
315	if (count > fill)	331	if (count > fill)
316	abort ();	332	assert (count <= fill);
317		333
318	memmove (data, data + count, fill -= count);	334	memmove (data, data + count, fill -= count);
319	}	335	}
320		336
321	bool byte_stream::put (u8 *data, unsigned int datalen)	337	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
334	return false;	350	return false;
335		351
336	data [fill++] = pkt->len >> 8;	352	data [fill++] = pkt->len >> 8;
337	data [fill++] = pkt->len;	353	data [fill++] = pkt->len;
338		354
339	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	355	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
340		356
341	return true;	357	return true;
342	}	358	}
343		359
344	vpn_packet *byte_stream::get ()	360	vpn_packet *byte_stream::get ()
345	{	361	{
		362	unsigned int len;
		363
		364	for (;;)
		365	{
346	int len = (data [0] << 8) \| data [1];	366	len = (data [0] << 8) \| data [1];
347		367
348	if (len > MAXSIZE && fill >= 2)	368	if (len <= MAXSIZE \|\| fill < 2)
349	abort (); // TODO handle this gracefully, connection reset	369	break;
350		370
		371	// TODO: handle this better than skipping, e.g. by reset
		372	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		373	remove (1);
		374	}
		375
351	if (fill < len + 2)	376	if (fill < len + 2)
352	return 0;	377	return 0;
353		378
354	vpn_packet *pkt = new vpn_packet;	379	vpn_packet *pkt = new vpn_packet;
355		380
356	pkt->len = len;	381	pkt->len = len;
357	memcpy (&((*pkt)[0]), data + 2, len);	382	memcpy (pkt->at (0), data + 2, len);
358	remove (len + 2);	383	remove (len + 2);
359		384
360	return pkt;	385	return pkt;
361	}	386	}
362		387
363	/////////////////////////////////////////////////////////////////////////////	388	/////////////////////////////////////////////////////////////////////////////
364		389
365	#define FLAG_QUERY ( 0 << 15)	390	#define FLAG_QUERY ( 0 << 15)
366	#define FLAG_RESPONSE ( 1 << 15)	391	#define FLAG_RESPONSE ( 1 << 15)
367	#define FLAG_OP_MASK (15 << 14)	392	#define FLAG_OP_MASK (15 << 11)
368	#define FLAG_OP_QUERY ( 0 << 11)	393	#define FLAG_OP_QUERY ( 0 << 11)
369	#define FLAG_AA ( 1 << 10)	394	#define FLAG_AA ( 1 << 10)
370	#define FLAG_TC ( 1 << 9)	395	#define FLAG_TC ( 1 << 9)
371	#define FLAG_RD ( 1 << 8)	396	#define FLAG_RD ( 1 << 8)
372	#define FLAG_RA ( 1 << 7)	397	#define FLAG_RA ( 1 << 7)
…		…
379	#define FLAG_RCODE_REFUSED ( 5 << 0)	404	#define FLAG_RCODE_REFUSED ( 5 << 0)
380		405
381	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	406	#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)	407	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
383		408
		409	struct dns_cfg
		410	{
		411	static int next_uid;
		412
		413	u8 id1, id2, id3, id4;
		414
		415	u8 version;
		416	u8 flags;
		417	u8 rrtype;
		418	u8 def_ttl;
		419
		420	u16 client;
		421	u16 uid; // to make request unique
		422
		423	u16 max_size;
		424	u8 seq_cdc;
		425	u8 req_cdc;
		426
		427	u8 rep_cdc;
		428	u8 delay; // time in 0.01s units that the server may delay replying packets
		429	u8 r3, r4;
		430
		431	u8 r5, r6, r7, r8;
		432
		433	void reset (int clientid);
		434	bool valid ();
		435	};
		436
		437	int dns_cfg::next_uid;
		438
		439	void dns_cfg::reset (int clientid)
		440	{
		441	id1 = 'G';
		442	id2 = 'V';
		443	id3 = 'P';
		444	id4 = 'E';
		445
		446	version = 1;
		447
		448	rrtype = RR_TYPE_TXT;
		449	flags = 0;
		450	def_ttl = 0;
		451	seq_cdc = 26;
		452	req_cdc = 62;
		453	rep_cdc = 0;
		454	max_size = htons (MAX_PKT_SIZE);
		455	client = htons (clientid);
		456	uid = next_uid++;
		457	delay = 0;
		458
		459	r3 = r4 = 0;
		460	r4 = r5 = r6 = r7 = 0;
		461	}
		462
		463	bool dns_cfg::valid ()
		464	{
		465	return id1 == 'G'
		466	&& id2 == 'V'
		467	&& id3 == 'P'
		468	&& id4 == 'E'
		469	&& seq_cdc == 26
		470	&& req_cdc == 62
		471	&& rep_cdc == 0
		472	&& version == 1;
		473	}
		474
384	struct dns_packet : net_packet	475	struct dns_packet : net_packet
385	{	476	{
386	u16 id;	477	u16 id;
387	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	478	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
388	u16 qdcount, ancount, nscount, arcount;	479	u16 qdcount, ancount, nscount, arcount;
389		480
390	u8 data[MAXSIZE - 6 * 2];	481	u8 data [MAXSIZE - 6 * 2];
391		482
392	int decode_label (char *data, int size, int &offs);	483	int decode_label (char *data, int size, int &offs);
393	};	484	};
394		485
395	int dns_packet::decode_label (char *data, int size, int &offs)	486	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
426	return data - orig;	517	return data - orig;
427	}	518	}
428		519
429	/////////////////////////////////////////////////////////////////////////////	520	/////////////////////////////////////////////////////////////////////////////
430		521
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	522	static u16 dns_id = 0; // TODO: should be per-vpn
444		523
445	static u16 next_id ()	524	static u16 next_id ()
446	{	525	{
		526	if (!dns_id)
		527	dns_id = time (0);
		528
447	// the simplest lsfr with periodicity 65535 i could find	529	// the simplest lsfr with periodicity 65535 i could find
448	dns_id = (dns_id << 1)	530	dns_id = (dns_id << 1)
449	\| (((dns_id >> 1)	531	\| (((dns_id >> 1)
450	^ (dns_id >> 2)	532	^ (dns_id >> 2)
451	^ (dns_id >> 4)	533	^ (dns_id >> 4)
452	^ (dns_id >> 15)) & 1);	534	^ (dns_id >> 15)) & 1);
453		535
454	return dns_id;	536	return dns_id;
455	}	537	}
456		538
457	dns_req::dns_req (connection *c)	539	struct dns_rcv;
458	: conn (c)	540	struct dns_snd;
		541
		542	struct dns_connection
459	{	543	{
460	next = 0;	544	connection *c;
		545	struct vpn *vpn;
		546
		547	dns_cfg cfg;
		548
		549	bool established;
		550
		551	tstamp last_received;
		552	tstamp last_sent;
		553	double min_latency;
		554	double poll_interval, send_interval;
		555
		556	vector<dns_rcv *> rcvpq;
		557
		558	byte_stream rcvdq; int rcvseq;
		559	byte_stream snddq; int sndseq;
		560
		561	void time_cb (time_watcher &w); time_watcher tw;
		562	void receive_rep (dns_rcv *r);
		563
		564	dns_connection (connection *c);
		565	~dns_connection ();
		566	};
		567
		568	struct dns_snd
		569	{
		570	dns_packet *pkt;
		571	tstamp timeout, sent;
		572	int retry;
		573	struct dns_connection *dns;
		574	int seqno;
		575	bool stdhdr;
		576
		577	void gen_stream_req (int seqno, byte_stream &stream);
		578	void gen_syn_req ();
		579
		580	dns_snd (dns_connection *dns);
		581	~dns_snd ();
		582	};
		583
		584	dns_snd::dns_snd (dns_connection *dns)
		585	: dns (dns)
		586	{
		587	timeout = 0;
461	retry = 0;	588	retry = 0;
		589	seqno = 0;
		590	sent = NOW;
		591	stdhdr = false;
462		592
463	pkt = new dns_packet;	593	pkt = new dns_packet;
464		594
465	pkt->id = next_id ();	595	pkt->id = next_id ();
466	}	596	}
467		597
		598	dns_snd::~dns_snd ()
		599	{
		600	delete pkt;
		601	}
		602
		603	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		604	{
		605	// add tunnel domain
		606	for (;;)
		607	{
		608	const char *end = strchr (domain, '.');
		609
		610	if (!end)
		611	end = domain + strlen (domain);
		612
		613	int len = end - domain;
		614
		615	pkt [offs++] = len;
		616	memcpy (pkt.at (offs), domain, len);
		617	offs += len;
		618
		619	if (!*end)
		620	break;
		621
		622	domain = end + 1;
		623	}
		624	}
		625
468	void dns_req::gen_stream_req (int seqno, byte_stream *stream)	626	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
469	{	627	{
		628	stdhdr = true;
470	this->seqno = seqno;	629	this->seqno = seqno;
		630
		631	timeout = NOW + INITIAL_TIMEOUT;
471		632
472	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	633	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
473	pkt->qdcount = htons (1);	634	pkt->qdcount = htons (1);
474		635
475	int offs = 6*2;	636	int offs = 6*2;
476	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	637	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,	638	// 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	639	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
479		640
480	char enc[256], *encp = enc;	641	char enc[256], *encp = enc;
481	encode_header (enc, THISNODE->id, seqno);	642	encode_header (enc, THISNODE->id, seqno);
482		643
483	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);	644	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
484		645
485	if (datalen > stream->size ())	646	if (datalen > stream.size ())
486	datalen = stream->size ();	647	datalen = stream.size ();
487		648
488	int enclen = cdc62.encode (enc + HDRSIZE, stream->begin (), datalen) + HDRSIZE;	649	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);	650	stream.remove (datalen);
497		651
498	while (enclen)	652	while (enclen)
499	{	653	{
500	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;	654	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
501		655
…		…
506	encp += lbllen;	660	encp += lbllen;
507		661
508	enclen -= lbllen;	662	enclen -= lbllen;
509	}	663	}
510		664
511	const char *suffix = THISNODE->domain;	665	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		666
533	(*pkt)[offs++] = 0;	667	(*pkt)[offs++] = 0;
534	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	668	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		669	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		670
		671	pkt->len = offs;
		672	}
		673
		674	void dns_snd::gen_syn_req ()
		675	{
		676	timeout = NOW + INITIAL_SYN_TIMEOUT;
		677
		678	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		679	pkt->qdcount = htons (1);
		680
		681	int offs = 6 * 2;
		682
		683	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
		684
		685	assert (elen <= MAX_LBL_SIZE);
		686
		687	(*pkt)[offs] = elen;
		688	offs += elen + 1;
		689	append_domain (*pkt, offs, dns->c->conf->domain);
		690
		691	(*pkt)[offs++] = 0;
		692	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
535	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	693	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
536		694
537	pkt->len = offs;	695	pkt->len = offs;
538	}	696	}
539		697
…		…
558	{	716	{
559	delete pkt;	717	delete pkt;
560	}	718	}
561		719
562	/////////////////////////////////////////////////////////////////////////////	720	/////////////////////////////////////////////////////////////////////////////
563		721
564	struct dns_cfg	722	dns_connection::dns_connection (connection *c)
		723	: c (c)
		724	, rcvdq (MAX_BACKLOG * 2)
		725	, snddq (MAX_BACKLOG * 2)
		726	, tw (this, &dns_connection::time_cb)
565	{	727	{
566	u8 id1, id2, id3;	728	vpn = c->vpn;
567	u8 def_ttl;
568	u8 unused1;
569	u16 max_size;
570	u8 flags1, flags2;
571	};
572		729
		730	established = false;
		731
		732	rcvseq = sndseq = 0;
		733
		734	last_sent = last_received = 0;
		735	poll_interval = 0.5; // starting here
		736	send_interval = 0.5; // starting rate
		737	min_latency = INITIAL_TIMEOUT;
		738	}
		739
		740	dns_connection::~dns_connection ()
		741	{
		742	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		743	i != rcvpq.end ();
		744	++i)
		745	delete *i;
		746	}
		747
573	void connection::dnsv4_receive_rep (struct dns_rcv *r)	748	void dns_connection::receive_rep (dns_rcv *r)
574	{	749	{
		750	if (r->datalen)
		751	{
		752	last_received = NOW;
		753	tw.trigger ();
		754
		755	poll_interval = send_interval;
		756	}
		757	else
		758	{
		759	poll_interval *= 1.5;
		760
		761	if (poll_interval > MAX_POLL_INTERVAL)
		762	poll_interval = MAX_POLL_INTERVAL;
		763	}
		764
575	dns_rcvpq.push_back (r);	765	rcvpq.push_back (r);
576		766
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:	767	redo:
584		768
585	// find next packet	769	// find next packet
586	for (vector<dns_rcv *>::iterator i = dns_rcvpq.end (); i-- != dns_rcvpq.begin (); )	770	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
587	if (SEQNO_EQ (dns_rcvseq, (*i)->seqno))	771	if (SEQNO_EQ (rcvseq, (*i)->seqno))
588	{	772	{
589	// enter the packet into our input stream	773	// enter the packet into our input stream
590	r = *i;	774	r = *i;
591		775
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	776	// 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)	777	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
595	if (SEQNO_EQ ((*j)->seqno, dns_rcvseq - MAX_WINDOW))	778	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
596	{	779	{
597	printf ("%d removing %d\n", THISNODE->id, (*j)->seqno);
598	delete *j;	780	delete *j;
599	dns_rcvpq.erase (j);	781	rcvpq.erase (j);
600	break;	782	break;
601	}	783	}
602		784
603	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;	785	rcvseq = (rcvseq + 1) & SEQNO_MASK;
604		786
605	if (!dns_snddq && !dns_rcvdq)	787	if (!rcvdq.put (r->data, r->datalen))
606	{	788	{
607	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);	789	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
608	dns_snddq = new byte_stream (MAX_BACKLOG);	790	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	}	791	}
612		792
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 ())	793	while (vpn_packet *pkt = rcvdq.get ())
617	{	794	{
618	sockinfo si;	795	sockinfo si;
619	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	796	si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4;
620		797
621	vpn->recv_vpn_packet (pkt, si);	798	vpn->recv_vpn_packet (pkt, si);
		799
		800	delete pkt;
622	}	801	}
623		802
624	// check for further packets	803	// check for further packets
625	goto redo;	804	goto redo;
626	}	805	}
627	}	806	}
628		807
629	dns_packet *	808	void
630	vpn::dnsv4_server (dns_packet *pkt)	809	vpn::dnsv4_server (dns_packet &pkt)
631	{	810	{
632	u16 flags = ntohs (pkt->flags);	811	u16 flags = ntohs (pkt.flags);
633		812
634	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
635	int offs = 6 * 2; // skip header	813	int offs = 6 * 2; // skip header
636		814
637	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	815	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
638		816
639	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	817	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
640	&& pkt->qdcount == htons (1))	818	&& pkt.qdcount == htons (1))
641	{	819	{
642	char qname[MAXSIZE];	820	char qname [MAXSIZE];
643	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	821	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
644		822
645	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	823	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
646	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	824	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
647		825
648	pkt->qdcount = htons (1);	826	pkt.qdcount = htons (1);
649	pkt->ancount = 0;	827	pkt.ancount = 0;
650	pkt->nscount = 0; // should be self, as other nameservers reply like this	828	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	829	pkt.arcount = 0; // a record for self, as other nameservers reply like this
652		830
653	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	831	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
654		832
655	int dlen = strlen (THISNODE->domain);	833	int dlen = strlen (THISNODE->domain);
656		834
657	if (qclass == RR_CLASS_IN	835	if (qclass == RR_CLASS_IN
658	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
659	&& qlen > dlen + 1 + HDRSIZE	836	&& qlen > dlen + 1
660	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	837	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
661	{	838	{
662	// correct class, domain: parse	839	// now generate reply
663	int client, seqno;	840	pkt.ancount = htons (1); // one answer RR
664	decode_header (qname, client, seqno);	841	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
665		842
666	u8 data[MAXSIZE];	843	if ((qtype == RR_TYPE_ANY
667	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	844	\|\| qtype == RR_TYPE_TXT
668		845	\|\| qtype == RR_TYPE_NULL)
669	printf ("cdc62.decode %d(%d): %02x %02x %02x %02x\n",
670	qlen - (dlen + 1 + HDRSIZE), datalen	846	&& 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	{	847	{
		848	// correct class, domain: parse
		849	int client, seqno;
		850	decode_header (qname, client, seqno);
		851
		852	u8 data[MAXSIZE];
		853	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
		854
		855	if (0 < client && client <= conns.size ())
		856	{
681	connection *c = conns [client - 1];	857	connection *c = conns [client - 1];
		858	dns_connection *dns = c->dns;
		859	dns_rcv *rcv;
		860	bool in_seq;
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	in_seq = dns->rcvseq == seqno;
		882
		883	// new packet, queue
		884	rcv = new dns_rcv (seqno, data, datalen);
		885	dns->receive_rep (rcv);
		886	}
		887
685	{	888	{
686	// already seen that request: simply reply with the cached reply	889	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
687	dns_rcv r = i;
688		890
689	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	891	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		892	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		893	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		894	pkt [offs++] = 0; pkt [offs++] = 0;
		895	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
690		896
691	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);	897	int rdlen_offs = offs += 2;
692	pkt->id = r->pkt->id;	898
693	goto duplicate_request;	899	if (dns)
		900	{
		901	int dlen = ntohs (dns->cfg.max_size) - offs;
		902
		903	// bind doesn't compress well, so reduce further by one label length
		904	dlen -= qlen;
		905
		906	// only put data into in-order sequence packets, if
		907	// we receive out-of-order packets we generate empty
		908	// replies
		909	while (dlen > 1 && !dns->snddq.empty () && in_seq)
		910	{
		911	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		912
		913	if (txtlen > dns->snddq.size ())
		914	txtlen = dns->snddq.size ();
		915
		916	pkt[offs++] = txtlen;
		917	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
		918	offs += txtlen;
		919	dns->snddq.remove (txtlen);
		920
		921	dlen -= txtlen + 1;
		922	}
		923
		924	// avoid empty TXT rdata
		925	if (offs == rdlen_offs)
		926	pkt[offs++] = 0;
		927
		928	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
		929	}
		930	else
		931	{
		932	// send RST
		933	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		934	pkt [offs++] = CMD_IP_RST;
		935	}
		936
		937	int rdlen = offs - rdlen_offs;
		938
		939	pkt [rdlen_offs - 2] = rdlen >> 8;
		940	pkt [rdlen_offs - 1] = rdlen;
		941
		942	if (dns)
		943	{
		944	// now update dns_rcv copy
		945	rcv->pkt->len = offs;
		946	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		947	}
694	}	948	}
695		949
696	// new packet, queue	950	duplicate_request: ;
697	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);	951	}
698	c->dnsv4_receive_rep (rcv);	952	else
699
700	// now generate reply
701	pkt->ancount = htons (1); // one answer RR
702	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	953	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		954	}
		955	else if (qtype == RR_TYPE_A
		956	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		957	{
		958	dns_cfg cfg;
		959	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		960	int client = ntohs (cfg.client);
703		961
704	(*pkt) [offs++] = 0xc0;
705	(pkt) [offs++] = 6 2; // same as in query section	962	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
706		963
707	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;	964	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
708	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;	965	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
709
710	(pkt) [offs++] = 0; (pkt) [offs++] = 0;	966	pkt [offs++] = 0; pkt [offs++] = 0;
711	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL	967	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		968	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
712		969
713	int dlen = MAX_PKT_SIZE - offs - 2;	970	slog (L_INFO, _("DNS: client %d connects"), client);
714		971
715	// bind doesn't compress well, so reduce further by one label length	972	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
716	dlen -= qlen;	973	pkt [offs++] = CMD_IP_REJ;
717		974
718	int rdlen_offs = offs += 2;	975	if (0 < client && client <= conns.size ())
719
720	while (c->dns_snddq
721	&& !c->dns_snddq->empty ()
722	&& dlen > 1)
723	{	976	{
724	int txtlen = dlen <= 255 ? dlen - 1 : 255;	977	connection *c = conns [client - 1];
725		978
726	if (txtlen > c->dns_snddq->size ())	979	if (cfg.valid ())
727	txtlen = c->dns_snddq->size ();	980	{
		981	pkt [offs - 1] = CMD_IP_SYN;
728		982
729	(*pkt)[offs++] = txtlen;	983	delete c->dns;
730	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);	984	c->dns = new dns_connection (c);
731	offs += txtlen;	985	c->dns->cfg = cfg;
732	c->dns_snddq->remove (txtlen);	986	}
733
734	dlen -= txtlen + 1;
735	}	987	}
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	}	988	}
752	else
753	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
754	}	989	}
755		990
756	pkt->len = offs;	991	pkt.len = offs;
757	}	992	}
758
759	return pkt;
760	}	993	}
761		994
762	void	995	void
763	vpn::dnsv4_client (dns_packet *pkt)	996	vpn::dnsv4_client (dns_packet &pkt)
764	{	997	{
765	u16 flags = ntohs (pkt->flags);	998	u16 flags = ntohs (pkt.flags);
766	int offs = 6 * 2; // skip header	999	int offs = 6 * 2; // skip header
767		1000
768	pkt->qdcount = ntohs (pkt->qdcount);	1001	pkt.qdcount = ntohs (pkt.qdcount);
769	pkt->ancount = ntohs (pkt->ancount);	1002	pkt.ancount = ntohs (pkt.ancount);
770		1003
771	// go through our request list and find the corresponding request	1004	// go through our request list and find the corresponding request
772	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	1005	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
773	i != dns_sndpq.end ();	1006	i != dns_sndpq.end ();
774	++i)	1007	++i)
775	if ((*i)->pkt->id == pkt->id)	1008	if ((*i)->pkt->id == pkt.id)
776	{	1009	{
		1010	dns_connection dns = (i)->dns;
777	connection c = (i)->conn;	1011	connection *c = dns->c;
778	int seqno = (*i)->seqno;	1012	int seqno = (*i)->seqno;
779	u8 data[MAXSIZE], *datap = data;	1013	u8 data[MAXSIZE], *datap = data;
780		1014
		1015	if ((*i)->retry)
		1016	{
		1017	dns->send_interval *= 1.01;
		1018	if (dns->send_interval > MAX_SEND_INTERVAL)
		1019	dns->send_interval = MAX_SEND_INTERVAL;
		1020	}
		1021	else
		1022	{
		1023	#if 0
		1024	dns->send_interval *= 0.999;
		1025	#endif
		1026	// the latency surely puts an upper bound on
		1027	// the minimum send interval
		1028	double latency = NOW - (*i)->sent;
		1029
		1030	if (latency < dns->min_latency)
		1031	dns->min_latency = latency;
		1032
		1033	if (dns->send_interval > dns->min_latency * LATENCY_FACTOR)
		1034	dns->send_interval = dns->min_latency * LATENCY_FACTOR;
		1035
		1036	if (dns->send_interval < MIN_SEND_INTERVAL)
		1037	dns->send_interval = MIN_SEND_INTERVAL;
		1038	}
		1039
781	delete *i;	1040	delete *i;
782	dns_sndpq.erase (i);	1041	dns_sndpq.erase (i);
783		1042
784	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	1043	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
785	{	1044	{
786	char qname[MAXSIZE];	1045	char qname[MAXSIZE];
787		1046
788	while (pkt->qdcount-- && offs < MAXSIZE - 4)	1047	while (pkt.qdcount-- && offs < MAXSIZE - 4)
789	{	1048	{
790	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1049	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
791	offs += 4; // skip qtype, qclass	1050	offs += 4; // skip qtype, qclass
792	}	1051	}
793		1052
794	while (pkt->ancount-- && offs < MAXSIZE - 10)	1053	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
795	{	1054	{
796	int qlen = //D
797	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1055	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
798		1056
799	printf ("got reply to <%.*s>\n", qlen, qname);//D
800
801	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1057	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
802	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1058	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
803	u32 ttl = (*pkt) [offs++] << 24;	1059	u32 ttl = pkt [offs++] << 24;
804	ttl \|= (*pkt) [offs++] << 16;	1060	ttl \|= pkt [offs++] << 16;
805	ttl \|= (*pkt) [offs++] << 8;	1061	ttl \|= pkt [offs++] << 8;
806	ttl \|= (*pkt) [offs++];	1062	ttl \|= pkt [offs++];
807
808	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1063	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
809		1064
810	if (rdlen <= MAXSIZE - offs)	1065	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
811	{	1066	{
812	// decode bytes, finally	1067	if (rdlen <= MAXSIZE - offs)
813
814	while (rdlen)
815	{	1068	{
		1069	// decode bytes, finally
		1070
		1071	while (rdlen)
		1072	{
816	int txtlen = (*pkt) [offs++];	1073	int txtlen = pkt [offs++];
817		1074
818	assert (txtlen + offs < MAXSIZE - 1);	1075	assert (txtlen + offs < MAXSIZE - 1);
819		1076
820	memcpy (datap, pkt->at (offs), txtlen);	1077	memcpy (datap, pkt.at (offs), txtlen);
821	datap += txtlen; offs += txtlen;	1078	datap += txtlen; offs += txtlen;
822		1079
823	rdlen -= txtlen + 1;	1080	rdlen -= txtlen + 1;
		1081	}
824	}	1082	}
825
826	}	1083	}
		1084	else if (qtype == RR_TYPE_A)
		1085	{
		1086	u8 ip [4];
827		1087
		1088	ip [0] = pkt [offs++];
		1089	ip [1] = pkt [offs++];
		1090	ip [2] = pkt [offs++];
		1091	ip [3] = pkt [offs++];
		1092
		1093	if (ip [0] == CMD_IP_1
		1094	&& ip [1] == CMD_IP_2
		1095	&& ip [2] == CMD_IP_3)
		1096	{
		1097	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
		1098
		1099	if (ip [3] == CMD_IP_RST)
		1100	{
		1101	slog (L_DEBUG, _("DNS: got tunnel RST request"));
		1102
		1103	delete dns; c->dns = 0;
		1104
		1105	return;
		1106	}
		1107	else if (ip [3] == CMD_IP_SYN)
		1108	{
		1109	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
		1110	dns->established = true;
		1111	}
		1112	else if (ip [3] == CMD_IP_REJ)
		1113	{
		1114	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1115	abort ();
		1116	}
		1117	else
		1118	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
		1119	}
		1120	else
		1121	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
		1122	ip [0], ip [1], ip [2], ip [3]);
		1123
		1124	return;
		1125	}
		1126
		1127	int client, rseqno;
		1128	decode_header (qname, client, rseqno);
		1129
		1130	if (client != THISNODE->id)
		1131	{
		1132	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
		1133	datap = 0;
		1134	}
		1135	else if (rseqno != seqno)
		1136	{
		1137	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
		1138	datap = 0;
		1139	}
828	}	1140	}
829	}	1141	}
830		1142
831	// todo: pkt now used	1143	// todo: pkt now used
		1144	if (datap)
832	c->dnsv4_receive_rep (new dns_rcv (seqno, data, datap - data));	1145	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
833		1146
834	break;	1147	break;
835	}	1148	}
836
837	delete pkt;
838	}	1149	}
839		1150
840	void	1151	void
841	vpn::dnsv4_ev (io_watcher &w, short revents)	1152	vpn::dnsv4_ev (io_watcher &w, short revents)
842	{	1153	{
…		…
844	{	1155	{
845	dns_packet *pkt = new dns_packet;	1156	dns_packet *pkt = new dns_packet;
846	struct sockaddr_in sa;	1157	struct sockaddr_in sa;
847	socklen_t sa_len = sizeof (sa);	1158	socklen_t sa_len = sizeof (sa);
848		1159
849	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1160	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
850		1161
851	if (pkt->len > 0)	1162	if (pkt->len > 0)
852	{	1163	{
853	if (pkt->flags & htons (FLAG_TC))	1164	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1165	dnsv4_client (*pkt);
		1166	else
854	{	1167	{
855	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));	1168	dnsv4_server (*pkt);
856	//TODO connection reset	1169	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
857	}	1170	}
858		1171
859	if (THISNODE->dns_port)	1172	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	}	1173	}
867	}	1174	}
868	}	1175	}
869		1176
870	bool	1177	bool
871	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1178	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
872	{	1179	{
873	// never initialized	1180	int client = ntohs (si.port);
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		1181
879	//dns_rcvseq = dns_sndseq = 0;	1182	assert (0 < client && client <= conns.size ());
880		1183
881	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);	1184	connection *c = conns [client - 1];
882	}	1185
		1186	if (!c->dns)
		1187	c->dns = new dns_connection (c);
883		1188
884	if (!dns_snddq->put (pkt))	1189	if (!c->dns->snddq.put (pkt))
885	return false;	1190	return false;
886		1191
887	// start timer if neccessary	1192	c->dns->tw.trigger ();
888	if (!THISNODE->dns_port && !dnsv4_tw.active)
889	dnsv4_cb (dnsv4_tw);
890		1193
891	return true;	1194	return true;
892	}	1195	}
893		1196
894	void	1197	void
		1198	connection::dnsv4_reset_connection ()
		1199	{
		1200	//delete dns; dns = 0; //TODO
		1201	}
		1202
		1203	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1204
		1205	void
895	connection::dnsv4_cb (time_watcher &w)	1206	dns_connection::time_cb (time_watcher &w)
896	{	1207	{
		1208	// servers have to be polled
		1209	if (THISNODE->dns_port)
		1210	return;
		1211
897	// check for timeouts and (re)transmit	1212	// check for timeouts and (re)transmit
898	tstamp next = NOW + 60;	1213	tstamp next = NOW + poll_interval;
899	dns_req *send = 0;	1214	dns_snd *send = 0;
900		1215
901	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1216	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
902	i != vpn->dns_sndpq.end ();	1217	i != vpn->dns_sndpq.end ();
903	++i)	1218	++i)
904	{	1219	{
905	dns_req r = i;	1220	dns_snd r = i;
906		1221
907	if (r->next <= NOW)	1222	if (r->timeout <= NOW)
908	{	1223	{
909	if (!send)	1224	if (!send)
910	{	1225	{
911	send = r;	1226	send = r;
912		1227
913	if (r->retry)//D
914	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
915	r->retry++;	1228	r->retry++;
916	r->next = NOW + r->retry;	1229	r->timeout = NOW + (r->retry * min_latency * 8.);
		1230
		1231	// the following code changes the query section a bit, forcing
		1232	// the forwarder to generate a new request
		1233	if (r->stdhdr)
		1234	{
		1235	//printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
		1236	//encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
		1237	}
917	}	1238	}
918	}	1239	}
919		1240	else
920	if (r->next < next)	1241	NEXT (r->timeout);
921	next = r->next;
922	}	1242	}
923		1243
924	if (!send	1244	if (!send)
		1245	{
		1246	// generate a new packet, if wise
		1247
		1248	if (!established)
		1249	{
		1250	if (vpn->dns_sndpq.empty ())
		1251	{
		1252	send = new dns_snd (this);
		1253
		1254	cfg.reset (THISNODE->id);
		1255	send->gen_syn_req ();
		1256	}
		1257	}
925	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)	1258	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
926	{	1259	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1260	{
		1261	if (last_sent + send_interval <= NOW)
		1262	{
		1263	//printf ("sending data request etc.\n"); //D
		1264	if (!snddq.empty () \|\| last_received + 1. > NOW)
		1265	{
		1266	poll_interval = send_interval;
		1267	NEXT (NOW + send_interval);
		1268	}
		1269
927	send = new dns_req (this);	1270	send = new dns_snd (this);
928	send->gen_stream_req (dns_sndseq, dns_snddq);	1271	send->gen_stream_req (sndseq, snddq);
		1272	send->timeout = NOW + min_latency * 8.;
		1273
		1274	sndseq = (sndseq + 1) & SEQNO_MASK;
		1275	}
		1276	else
		1277	NEXT (last_sent + send_interval);
		1278	}
		1279
		1280	if (send)
929	vpn->dns_sndpq.push_back (send);	1281	vpn->dns_sndpq.push_back (send);
930
931	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
932	}	1282	}
933
934	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
935		1283
936	if (send)	1284	if (send)
937	{	1285	{
938	dns_packet *pkt = send->pkt;	1286	last_sent = NOW;
939		1287	sendto (vpn->dnsv4_fd,
940	next = min_next;	1288	send->pkt->at (0), send->pkt->len, 0,
941		1289	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	}	1290	}
944	else if (next < min_next)	1291
945	next = min_next;	1292	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1293	poll_interval, send_interval, next - NOW,
		1294	vpn->dns_sndpq.size (), snddq.size (),
		1295	rcvpq.size ());
		1296
		1297	// TODO: no idea when this happens, but when next < NOW, we have a problem
		1298	if (next < NOW + 0.001)
		1299	next = NOW + 0.1;
946		1300
947	w.start (next);	1301	w.start (next);
948	}	1302	}
949		1303
950	#endif	1304	#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 1.30 by pcg, Mon Mar 14 17:40:01 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 1.30 by pcg, Mon Mar 14 17:40:01 2005 UTC