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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs.
Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC

…		…
43		43
44	#include "netcompat.h"	44	#include "netcompat.h"
45		45
46	#include "vpn.h"	46	#include "vpn.h"
47		47
48	#define MIN_RETRY 1.	48	#define MIN_POLL_INTERVAL .2 // how often to poll minimally when the server is having data
49	#define MAX_RETRY 6.	49	#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data
		50	#define ACTIVITY_INTERVAL 5.
		51
		52	#define INITIAL_TIMEOUT 1.
		53	#define INITIAL_SYN_TIMEOUT 2.
		54
		55	#define MIN_SEND_INTERVAL (1./1000.)
		56	#define MAX_SEND_INTERVAL 0.5 // optimistic?
50		57
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	58	#define MAX_OUTSTANDING 400 // max. outstanding requests
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	59	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING
53	#define MAX_RATE 100 // requests/s	60	#define MAX_RATE 100 // requests/s
54	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	61	#define MAX_BACKLOG (100*1024) // size of protocol backlog, 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 220 // 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 byte sless give room for one reply byte
59		66
…		…
61	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	68	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
62		69
63	#define MAX_LBL_SIZE 63	70	#define MAX_LBL_SIZE 63
64	#define MAX_PKT_SIZE 512	71	#define MAX_PKT_SIZE 512
65		72
		73	#define RR_TYPE_A 1
		74	#define RR_TYPE_NULL 10
66	#define RR_TYPE_TXT 16	75	#define RR_TYPE_TXT 16
67	#define RR_TYPE_ANY 255	76	#define RR_TYPE_ANY 255
		77
68	#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
69		86
70	// works for cmaps up to 255 (not 256!)	87	// works for cmaps up to 255 (not 256!)
71	struct charmap	88	struct charmap
72	{	89	{
73	enum { INVALID = (u8)255 };	90	enum { INVALID = (u8)255 };
…		…
153	return dec_len [len];	170	return dec_len [len];
154	}	171	}
155		172
156	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	173	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
157	{	174	{
158	if (!len)	175	if (!len \|\| len > MAX_DEC_LEN)
159	return 0;	176	return 0;
160		177
161	int elen = encode_len (len);	178	int elen = encode_len (len);
162		179
163	mp_limb_t m [MAX_LIMBS];	180	mp_limb_t m [MAX_LIMBS];
…		…
182	return elen;	199	return elen;
183	}	200	}
184		201
185	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	202	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
186	{	203	{
187	if (!len)	204	if (!len \|\| len > MAX_ENC_LEN)
188	return 0;	205	return 0;
189		206
190	u8 src_ [MAX_ENC_LEN];	207	u8 src_ [MAX_ENC_LEN];
191	unsigned int elen = 0;	208	unsigned int elen = 0;
192		209
…		…
239	}	256	}
240	abort ();	257	abort ();
241	}	258	}
242	#endif	259	#endif
243		260
244	// the following sequence has been crafted to	261	//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
245	// a) look somewhat random
246	// b) the even (and odd) indices never share the same character as upper/lowercase
247	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)
248	// the other sequences are obviously derived
249	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	262	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
250	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	263	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	264	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
252	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	265	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
253		266
…		…
331	return false;	344	return false;
332		345
333	data [fill++] = pkt->len >> 8;	346	data [fill++] = pkt->len >> 8;
334	data [fill++] = pkt->len;	347	data [fill++] = pkt->len;
335		348
336	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	349	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
337		350
338	return true;	351	return true;
339	}	352	}
340		353
341	vpn_packet *byte_stream::get ()	354	vpn_packet *byte_stream::get ()
…		…
349	return 0;	362	return 0;
350		363
351	vpn_packet *pkt = new vpn_packet;	364	vpn_packet *pkt = new vpn_packet;
352		365
353	pkt->len = len;	366	pkt->len = len;
354	memcpy (&((*pkt)[0]), data + 2, len);	367	memcpy (pkt->at (0), data + 2, len);
355	remove (len + 2);	368	remove (len + 2);
356		369
357	return pkt;	370	return pkt;
358	}	371	}
359		372
…		…
376	#define FLAG_RCODE_REFUSED ( 5 << 0)	389	#define FLAG_RCODE_REFUSED ( 5 << 0)
377		390
378	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	391	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
379	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)	392	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
380		393
		394	struct dns_cfg
		395	{
		396	static int next_uid;
		397
		398	u8 id1, id2, id3, id4;
		399	u8 version;
		400	u8 rrtype;
		401	u8 flags;
		402	u8 def_ttl;
		403	u8 rcv_cdc;
		404	u8 snd_cdc;
		405	u16 max_size;
		406	u16 client;
		407	u16 uid; // to make request unique
		408
		409	u8 reserved[8];
		410
		411	void reset (int clientid);
		412	bool valid ();
		413	};
		414
		415	int dns_cfg::next_uid;
		416
		417	void dns_cfg::reset (int clientid)
		418	{
		419	id1 = 'G';
		420	id2 = 'V';
		421	id3 = 'P';
		422	id4 = 'E';
		423
		424	version = 1;
		425
		426	rrtype = RR_TYPE_TXT;
		427	flags = 0;
		428	def_ttl = 0;
		429	rcv_cdc = 0;
		430	snd_cdc = 62;
		431	max_size = ntohs (MAX_PKT_SIZE);
		432	client = ntohs (clientid);
		433	uid = next_uid++;
		434
		435	memset (reserved, 0, 8);
		436	}
		437
		438	bool dns_cfg::valid ()
		439	{
		440	return id1 == 'G'
		441	&& id2 == 'V'
		442	&& id3 == 'P'
		443	&& id4 == 'E'
		444	&& version == 1
		445	&& flags == 0
		446	&& rcv_cdc == 0
		447	&& snd_cdc == 62
		448	&& max_size == ntohs (MAX_PKT_SIZE);
		449	}
		450
381	struct dns_packet : net_packet	451	struct dns_packet : net_packet
382	{	452	{
383	u16 id;	453	u16 id;
384	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	454	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
385	u16 qdcount, ancount, nscount, arcount;	455	u16 qdcount, ancount, nscount, arcount;
…		…
423	return data - orig;	493	return data - orig;
424	}	494	}
425		495
426	/////////////////////////////////////////////////////////////////////////////	496	/////////////////////////////////////////////////////////////////////////////
427		497
428	struct dns_req	498	struct dns_snd
429	{	499	{
430	dns_packet *pkt;	500	dns_packet *pkt;
431	tstamp next;	501	tstamp timeout, sent;
432	int retry;	502	int retry;
433	struct dns_connection *dns;	503	struct dns_connection *dns;
434	int seqno;	504	int seqno;
435		505
436	dns_req (dns_connection *dns);	506	dns_snd (dns_connection *dns);
437	void gen_stream_req (int seqno, byte_stream &stream);	507	void gen_stream_req (int seqno, byte_stream &stream);
		508	void gen_syn_req (const dns_cfg &cfg);
438	};	509	};
439		510
440	static u16 dns_id = 12098; // TODO: should be per-vpn	511	static u16 dns_id = 12098; // TODO: should be per-vpn
441		512
442	static u16 next_id ()	513	static u16 next_id ()
…		…
449	^ (dns_id >> 15)) & 1);	520	^ (dns_id >> 15)) & 1);
450		521
451	return dns_id;	522	return dns_id;
452	}	523	}
453		524
454	dns_req::dns_req (dns_connection *dns)	525	dns_snd::dns_snd (dns_connection *dns)
455	: dns (dns)	526	: dns (dns)
456	{	527	{
457	next = 0;	528	timeout = 0;
458	retry = 0;	529	retry = 0;
		530	seqno = 0;
459		531
460	pkt = new dns_packet;	532	pkt = new dns_packet;
461		533
462	pkt->id = next_id ();	534	pkt->id = next_id ();
463	}	535	}
464		536
		537	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		538	{
		539	// add tunnel domain
		540	for (;;)
		541	{
		542	const char *end = strchr (domain, '.');
		543
		544	if (!end)
		545	end = domain + strlen (domain);
		546
		547	int len = end - domain;
		548
		549	pkt [offs++] = len;
		550	memcpy (pkt.at (offs), domain, len);
		551	offs += len;
		552
		553	if (!*end)
		554	break;
		555
		556	domain = end + 1;
		557	}
		558	}
		559
465	void dns_req::gen_stream_req (int seqno, byte_stream &stream)	560	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
466	{	561	{
467	this->seqno = seqno;	562	this->seqno = seqno;
		563
		564	timeout = NOW + INITIAL_TIMEOUT;
468		565
469	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	566	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
470	pkt->qdcount = htons (1);	567	pkt->qdcount = htons (1);
471		568
472	int offs = 6*2;	569	int offs = 6*2;
…		…
496	encp += lbllen;	593	encp += lbllen;
497		594
498	enclen -= lbllen;	595	enclen -= lbllen;
499	}	596	}
500		597
501	const char *suffix = THISNODE->domain;	598	append_domain (*pkt, offs, THISNODE->domain);
502
503	// add tunnel domain
504	for (;;)
505	{
506	const char *end = strchr (suffix, '.');
507
508	if (!end)
509	end = suffix + strlen (suffix);
510
511	int len = end - suffix;
512
513	(*pkt)[offs++] = len;
514	memcpy (&((*pkt)[offs]), suffix, len);
515	offs += len;
516
517	if (!*end)
518	break;
519
520	suffix = end + 1;
521	}
522		599
523	(*pkt)[offs++] = 0;	600	(*pkt)[offs++] = 0;
524	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	601	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		602	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		603
		604	pkt->len = offs;
		605	}
		606
		607	void dns_snd::gen_syn_req (const dns_cfg &cfg)
		608	{
		609	timeout = NOW + INITIAL_SYN_TIMEOUT;
		610
		611	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		612	pkt->qdcount = htons (1);
		613
		614	int offs = 6*2;
		615
		616	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));
		617
		618	assert (elen <= MAX_LBL_SIZE);
		619
		620	(*pkt)[offs] = elen;
		621	offs += elen + 1;
		622	append_domain (*pkt, offs, THISNODE->domain);
		623
		624	(*pkt)[offs++] = 0;
		625	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
525	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	626	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
526		627
527	pkt->len = offs;	628	pkt->len = offs;
528	}	629	}
529		630
…		…
554	struct dns_connection	655	struct dns_connection
555	{	656	{
556	connection *c;	657	connection *c;
557	struct vpn *vpn;	658	struct vpn *vpn;
558		659
		660	dns_cfg cfg;
		661
		662	bool established;
		663
		664	tstamp last_received;
		665	tstamp last_sent;
		666	double poll_interval, send_interval;
		667
559	vector<dns_rcv *> rcvpq;	668	vector<dns_rcv *> rcvpq;
560		669
561	int rcvseq;
562	int sndseq;
563
564	byte_stream rcvdq;	670	byte_stream rcvdq; int rcvseq;
565	byte_stream snddq;	671	byte_stream snddq; int sndseq;
566		672
567	void time_cb (time_watcher &w); time_watcher tw;	673	void time_cb (time_watcher &w); time_watcher tw;
568	void receive_rep (dns_rcv *r);	674	void receive_rep (dns_rcv *r);
569		675
570	dns_connection (connection *c);	676	dns_connection (connection *c);
…		…
577	, snddq (MAX_BACKLOG * 2)	683	, snddq (MAX_BACKLOG * 2)
578	, tw (this, &dns_connection::time_cb)	684	, tw (this, &dns_connection::time_cb)
579	{	685	{
580	vpn = c->vpn;	686	vpn = c->vpn;
581		687
		688	established = false;
		689
582	rcvseq = sndseq = 0;	690	rcvseq = sndseq = 0;
		691
		692	last_sent = last_received = 0;
		693	poll_interval = MIN_POLL_INTERVAL;
		694	send_interval = 0.2; // starting rate
583	}	695	}
584		696
585	dns_connection::~dns_connection ()	697	dns_connection::~dns_connection ()
586	{	698	{
587	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	699	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
588	i != rcvpq.end ();	700	i != rcvpq.end ();
589	++i)	701	++i)
590	delete *i;	702	delete *i;
591	}	703	}
592		704
593	struct dns_cfg
594	{
595	u8 id1, id2, id3;
596	u8 def_ttl;
597	u8 unused1;
598	u16 max_size;
599	u8 flags1, flags2;
600	};
601
602	void dns_connection::receive_rep (dns_rcv *r)	705	void dns_connection::receive_rep (dns_rcv *r)
603	{	706	{
		707	if (r->datalen)
		708	{
		709	last_received = NOW;
		710	tw.trigger ();
		711
		712	poll_interval *= 0.99;
		713	if (poll_interval > MIN_POLL_INTERVAL)
		714	poll_interval = MIN_POLL_INTERVAL;
		715	}
		716	else
		717	{
		718	poll_interval *= 1.1;
		719	if (poll_interval > MAX_POLL_INTERVAL)
		720	poll_interval = MAX_POLL_INTERVAL;
		721	}
		722
604	rcvpq.push_back (r);	723	rcvpq.push_back (r);
605		724
606	redo:	725	redo:
607		726
608	// find next packet	727	// find next packet
…		…
637	// check for further packets	756	// check for further packets
638	goto redo;	757	goto redo;
639	}	758	}
640	}	759	}
641		760
642	dns_packet *	761	void
643	vpn::dnsv4_server (dns_packet *pkt)	762	vpn::dnsv4_server (dns_packet &pkt)
644	{	763	{
645	u16 flags = ntohs (pkt->flags);	764	u16 flags = ntohs (pkt.flags);
646		765
647	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
648	int offs = 6 * 2; // skip header	766	int offs = 6 * 2; // skip header
649		767
650	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	768	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
651		769
652	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	770	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
653	&& pkt->qdcount == htons (1))	771	&& pkt.qdcount == htons (1))
654	{	772	{
655	char qname[MAXSIZE];	773	char qname[MAXSIZE];
656	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	774	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
657		775
658	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	776	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
659	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	777	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
660		778
661	pkt->qdcount = htons (1);	779	pkt.qdcount = htons (1);
662	pkt->ancount = 0;	780	pkt.ancount = 0;
663	pkt->nscount = 0; // should be self, as other nameservers reply like this	781	pkt.nscount = 0; // should be self, as other nameservers reply like this
664	pkt->arcount = 0; // a record for self, as other nameservers reply like this	782	pkt.arcount = 0; // a record for self, as other nameservers reply like this
665		783
666	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	784	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);
667		785
668	int dlen = strlen (THISNODE->domain);	786	int dlen = strlen (THISNODE->domain);
669		787
670	if (qclass == RR_CLASS_IN	788	if (qclass == RR_CLASS_IN
671	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
672	&& qlen > dlen + 1 + HDRSIZE	789	&& qlen > dlen + 1
673	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	790	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
674	{	791	{
675	// correct class, domain: parse	792	// now generate reply
676	int client, seqno;	793	pkt.ancount = htons (1); // one answer RR
677	decode_header (qname, client, seqno);	794	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
678		795
679	u8 data[MAXSIZE];	796	if ((qtype == RR_TYPE_ANY
680	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	797	\|\| qtype == RR_TYPE_TXT
681		798	\|\| qtype == RR_TYPE_NULL)
682	if (0 < client && client <= conns.size ())	799	&& qlen > dlen + 1 + HDRSIZE)
683	{	800	{
684	connection *c = conns [client - 1];	801	// correct class, domain: parse
		802	int client, seqno;
		803	decode_header (qname, client, seqno);
685		804
686	if (!c->dns)	805	u8 data[MAXSIZE];
687	c->dns = new dns_connection (c);	806	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
688		807
689	dns_connection *dns = c->dns;	808	if (0 < client && client <= conns.size ())
690
691	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
692	if (SEQNO_EQ ((*i)->seqno, seqno))
693	{
694	// already seen that request: simply reply with the cached reply
695	dns_rcv r = i;
696
697	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D
698
699	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);
700	pkt->id = r->pkt->id;
701	goto duplicate_request;
702	}
703
704	// new packet, queue
705	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);
706	dns->receive_rep (rcv);
707
708	// now generate reply
709	pkt->ancount = htons (1); // one answer RR
710	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
711
712	(*pkt) [offs++] = 0xc0;
713	(pkt) [offs++] = 6 2; // same as in query section
714
715	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;
716	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;
717
718	(pkt) [offs++] = 0; (pkt) [offs++] = 0;
719	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL
720
721	int dlen = MAX_PKT_SIZE - offs - 2;
722
723	// bind doesn't compress well, so reduce further by one label length
724	dlen -= qlen;
725
726	int rdlen_offs = offs += 2;
727
728	while (dlen > 1 && !dns->snddq.empty ())
729	{	809	{
		810	connection *c = conns [client - 1];
		811	dns_connection *dns = c->dns;
		812	dns_rcv *rcv;
		813
		814	if (dns)
		815	{
		816	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
		817	if (SEQNO_EQ ((*i)->seqno, seqno))
		818	{
		819	// already seen that request: simply reply with the cached reply
		820	dns_rcv r = i;
		821
		822	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D
		823
		824	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		825	pkt.id = r->pkt->id;
		826	goto duplicate_request;
		827	}
		828
		829	// new packet, queue
		830	rcv = new dns_rcv (seqno, data, datalen);
		831	dns->receive_rep (rcv);
		832	}
		833
		834	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		835
		836	// type
		837	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		838	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype;
		839
		840	// class
		841	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN;
		842
		843	// TTL
		844	pkt [offs++] = 0; pkt [offs++] = 0;
		845	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0;
		846
		847	int rdlen_offs = offs += 2;
		848
		849	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
		850	// bind doesn't compress well, so reduce further by one label length
		851	dlen -= qlen;
		852
		853	if (dns)
		854	{
		855	while (dlen > 1 && !dns->snddq.empty ())
		856	{
730	int txtlen = dlen <= 255 ? dlen - 1 : 255;	857	int txtlen = dlen <= 255 ? dlen - 1 : 255;
731		858
732	if (txtlen > dns->snddq.size ())	859	if (txtlen > dns->snddq.size ())
733	txtlen = dns->snddq.size ();	860	txtlen = dns->snddq.size ();
734		861
735	(*pkt)[offs++] = txtlen;	862	pkt[offs++] = txtlen;
736	memcpy (pkt->at (offs), dns->snddq.begin (), txtlen);	863	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
737	offs += txtlen;	864	offs += txtlen;
738	dns->snddq.remove (txtlen);	865	dns->snddq.remove (txtlen);
739		866
740	dlen -= txtlen + 1;	867	dlen -= txtlen + 1;
		868	}
		869
		870	// avoid empty TXT rdata
		871	if (offs == rdlen_offs)
		872	pkt[offs++] = 0;
		873	}
		874	else
		875	{
		876	// send RST
		877	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		878	pkt [offs++] = CMD_IP_RST;
		879	}
		880
		881	int rdlen = offs - rdlen_offs;
		882
		883	pkt [rdlen_offs - 2] = rdlen >> 8;
		884	pkt [rdlen_offs - 1] = rdlen;
		885
		886	if (dns)
		887	{
		888	// now update dns_rcv copy
		889	rcv->pkt->len = offs;
		890	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		891	}
		892
		893	duplicate_request: ;
741	}	894	}
742		895	else
743	// avoid empty TXT rdata	896	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
744	if (offs == rdlen_offs)
745	(*pkt)[offs++] = 0;
746
747	int rdlen = offs - rdlen_offs;
748
749	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
750	(*pkt) [rdlen_offs - 1] = rdlen;
751
752	// now update dns_rcv copy
753	rcv->pkt->len = offs;
754	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
755
756	duplicate_request: ;
757	}	897	}
758	else	898	else if (qtype == RR_TYPE_A
759	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	899	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		900	{
		901	dns_cfg cfg;
		902	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		903	int client = ntohs (cfg.client);
		904
		905	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		906
		907	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
		908	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		909	pkt [offs++] = 0; pkt [offs++] = 0;
		910	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		911	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
		912
		913	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);
		914
		915	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		916	pkt [offs++] = CMD_IP_REJ;
		917
		918	if (0 < client && client <= conns.size ())
		919	{
		920	connection *c = conns [client - 1];
		921
		922	if (cfg.valid ())
		923	{
		924	pkt [offs - 1] = CMD_IP_SYN;
		925
		926	delete c->dns;
		927	c->dns = new dns_connection (c);
		928	c->dns->cfg = cfg;
		929	}
		930	}
		931	}
760	}	932	}
761		933
762	pkt->len = offs;	934	pkt.len = offs;
763	}	935	}
764
765	return pkt;
766	}	936	}
767		937
768	void	938	void
769	vpn::dnsv4_client (dns_packet *pkt)	939	vpn::dnsv4_client (dns_packet &pkt)
770	{	940	{
771	u16 flags = ntohs (pkt->flags);	941	u16 flags = ntohs (pkt.flags);
772	int offs = 6 * 2; // skip header	942	int offs = 6 * 2; // skip header
773		943
774	pkt->qdcount = ntohs (pkt->qdcount);	944	pkt.qdcount = ntohs (pkt.qdcount);
775	pkt->ancount = ntohs (pkt->ancount);	945	pkt.ancount = ntohs (pkt.ancount);
776		946
777	// go through our request list and find the corresponding request	947	// go through our request list and find the corresponding request
778	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	948	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
779	i != dns_sndpq.end ();	949	i != dns_sndpq.end ();
780	++i)	950	++i)
781	if ((*i)->pkt->id == pkt->id)	951	if ((*i)->pkt->id == pkt.id)
782	{	952	{
783	dns_connection dns = (i)->dns;	953	dns_connection dns = (i)->dns;
784	int seqno = (*i)->seqno;	954	int seqno = (*i)->seqno;
785	u8 data[MAXSIZE], *datap = data;	955	u8 data[MAXSIZE], *datap = data;
786		956
		957	if ((*i)->retry)
		958	{
		959	dns->send_interval *= 1.01;
		960	if (dns->send_interval < MAX_SEND_INTERVAL)
		961	dns->send_interval = MAX_SEND_INTERVAL;
		962	}
		963	else
		964	{
		965	dns->send_interval *= 0.99;
		966	if (dns->send_interval < MIN_SEND_INTERVAL)
		967	dns->send_interval = MIN_SEND_INTERVAL;
		968
		969	// the latency surely puts an upper bound on
		970	// the minimum send interval
		971	if (dns->send_interval > NOW - (*i)->sent)
		972	dns->send_interval = NOW - (*i)->sent;
		973	}
		974
787	delete *i;	975	delete *i;
788	dns_sndpq.erase (i);	976	dns_sndpq.erase (i);
789		977
790	if (flags & FLAG_RESPONSE && !(flags & (FLAG_OP_MASK \| FLAG_TC)))	978	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
791	{	979	{
792	char qname[MAXSIZE];	980	char qname[MAXSIZE];
793		981
794	while (pkt->qdcount-- && offs < MAXSIZE - 4)	982	while (pkt.qdcount-- && offs < MAXSIZE - 4)
795	{	983	{
796	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	984	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
797	offs += 4; // skip qtype, qclass	985	offs += 4; // skip qtype, qclass
798	}	986	}
799		987
800	while (pkt->ancount-- && offs < MAXSIZE - 10 && datap)	988	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
801	{	989	{
802	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	990	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
803		991
804	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	992	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
805	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	993	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
806	u32 ttl = (*pkt) [offs++] << 24;	994	u32 ttl = pkt [offs++] << 24;
807	ttl \|= (*pkt) [offs++] << 16;	995	ttl \|= pkt [offs++] << 16;
808	ttl \|= (*pkt) [offs++] << 8;	996	ttl \|= pkt [offs++] << 8;
809	ttl \|= (*pkt) [offs++];	997	ttl \|= pkt [offs++];
810
811	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	998	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
812		999
813	if (rdlen <= MAXSIZE - offs)	1000	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
814	{	1001	{
815	// decode bytes, finally	1002	if (rdlen <= MAXSIZE - offs)
816
817	while (rdlen)
818	{	1003	{
		1004	// decode bytes, finally
		1005
		1006	while (rdlen)
		1007	{
819	int txtlen = (*pkt) [offs++];	1008	int txtlen = pkt [offs++];
820		1009
821	assert (txtlen + offs < MAXSIZE - 1);	1010	assert (txtlen + offs < MAXSIZE - 1);
822		1011
823	memcpy (datap, pkt->at (offs), txtlen);	1012	memcpy (datap, pkt.at (offs), txtlen);
824	datap += txtlen; offs += txtlen;	1013	datap += txtlen; offs += txtlen;
825		1014
826	rdlen -= txtlen + 1;	1015	rdlen -= txtlen + 1;
		1016	}
827	}	1017	}
		1018	}
		1019	else if (qtype == RR_TYPE_A)
		1020	{
		1021	u8 ip [4];
		1022
		1023	ip [0] = pkt [offs++];
		1024	ip [1] = pkt [offs++];
		1025	ip [2] = pkt [offs++];
		1026	ip [3] = pkt [offs++];
		1027
		1028	if (ip [0] == CMD_IP_1
		1029	&& ip [1] == CMD_IP_2
		1030	&& ip [2] == CMD_IP_3)
		1031	{
		1032	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);
		1033
		1034	if (ip [3] == CMD_IP_RST)
		1035	{
		1036	slog (L_DEBUG, _("got tunnel RST request"));
		1037
		1038	connection *c = dns->c;
		1039	delete c->dns; c->dns = 0;
		1040
		1041	return;
		1042	}
		1043	else if (ip [3] == CMD_IP_SYN)
		1044	dns->established = true;
		1045	else
		1046	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);
		1047	}
		1048	else
		1049	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),
		1050	ip [0], ip [1], ip [2], ip [3]);
		1051
		1052	return;
828	}	1053	}
829		1054
830	int client, rseqno;	1055	int client, rseqno;
831	decode_header (qname, client, rseqno);	1056	decode_header (qname, client, rseqno);
832		1057
…		…
847	if (datap)	1072	if (datap)
848	dns->receive_rep (new dns_rcv (seqno, data, datap - data));	1073	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
849		1074
850	break;	1075	break;
851	}	1076	}
852
853	delete pkt;
854	}	1077	}
855		1078
856	void	1079	void
857	vpn::dnsv4_ev (io_watcher &w, short revents)	1080	vpn::dnsv4_ev (io_watcher &w, short revents)
858	{	1081	{
…		…
860	{	1083	{
861	dns_packet *pkt = new dns_packet;	1084	dns_packet *pkt = new dns_packet;
862	struct sockaddr_in sa;	1085	struct sockaddr_in sa;
863	socklen_t sa_len = sizeof (sa);	1086	socklen_t sa_len = sizeof (sa);
864		1087
865	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1088	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
866		1089
867	if (pkt->len > 0)	1090	if (pkt->len > 0)
868	{	1091	{
869	if (pkt->flags & htons (FLAG_TC))
870	{
871	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));
872	//TODO connection reset
873	}
874
875	if (THISNODE->dns_port)	1092	if (THISNODE->dns_port)
876	{	1093	{
877	pkt = dnsv4_server (pkt);	1094	dnsv4_server (*pkt);
878	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);	1095	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
879	}	1096	}
880	else	1097	else
881	dnsv4_client (pkt);	1098	dnsv4_client (*pkt);
		1099
		1100	delete pkt;
882	}	1101	}
883	}	1102	}
884	}	1103	}
885		1104
886	bool	1105	bool
…		…
890	dns = new dns_connection (this);	1109	dns = new dns_connection (this);
891		1110
892	if (!dns->snddq.put (pkt))	1111	if (!dns->snddq.put (pkt))
893	return false;	1112	return false;
894		1113
895	// start timer if neccessary
896	if (!THISNODE->dns_port && !dns->tw.active)
897	dns->tw.trigger ();	1114	dns->tw.trigger ();
898		1115
899	return true;	1116	return true;
900	}	1117	}
		1118
		1119	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
901		1120
902	void	1121	void
903	dns_connection::time_cb (time_watcher &w)	1122	dns_connection::time_cb (time_watcher &w)
904	{	1123	{
		1124	// servers have to be polled
		1125	if (THISNODE->dns_port)
		1126	return;
		1127
905	// check for timeouts and (re)transmit	1128	// check for timeouts and (re)transmit
906	tstamp next = NOW + 60;	1129	tstamp next = NOW + poll_interval;
907	dns_req *send = 0;	1130	dns_snd *send = 0;
908		1131
909	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1132	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
910	i != vpn->dns_sndpq.end ();	1133	i != vpn->dns_sndpq.end ();
911	++i)	1134	++i)
912	{	1135	{
913	dns_req r = i;	1136	dns_snd r = i;
914		1137
915	if (r->next <= NOW)	1138	if (r->timeout <= NOW)
916	{	1139	{
917	if (!send)	1140	if (!send)
918	{	1141	{
919	send = r;	1142	send = r;
920		1143
921	if (r->retry)//D
922	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
923	r->retry++;	1144	r->retry++;
924	r->next = NOW + r->retry;	1145	r->timeout = NOW + r->retry;
925	}	1146	}
926	}	1147	}
927
928	if (r->next < next)	1148	else if (r->timeout < next)
929	next = r->next;	1149	NEXT (r->timeout);
		1150	}
		1151
		1152	if (last_sent + send_interval <= NOW)
930	}	1153	{
931
932	if (!send	1154	if (!send)
		1155	{
		1156	// generate a new packet, if wise
		1157
		1158	if (!established)
		1159	{
		1160	if (vpn->dns_sndpq.empty ())
		1161	{
		1162	send = new dns_snd (this);
		1163
		1164	cfg.reset (THISNODE->id);
		1165	send->gen_syn_req (cfg);
		1166	}
		1167	}
933	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)	1168	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
934	{	1169	{
935	send = new dns_req (this);	1170	send = new dns_snd (this);
936	send->gen_stream_req (sndseq, snddq);	1171	send->gen_stream_req (sndseq, snddq);
		1172
		1173	sndseq = (sndseq + 1) & SEQNO_MASK;
		1174	}
		1175
		1176	if (send)
937	vpn->dns_sndpq.push_back (send);	1177	vpn->dns_sndpq.push_back (send);
		1178	}
938		1179
939	sndseq = (sndseq + 1) & SEQNO_MASK;
940	}
941
942	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
943
944	if (send)	1180	if (send)
945	{	1181	{
946	dns_packet *pkt = send->pkt;	1182	printf ("send pkt\n");
		1183	last_sent = NOW;
947		1184
948	next = min_next;	1185	if (!send->retry)
		1186	send->sent = NOW;
949		1187
950	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0,	1188	sendto (vpn->dnsv4_fd,
		1189	send->pkt->at (0), send->pkt->len, 0,
951	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1190	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
		1191	}
952	}	1192	}
953	else if (next < min_next)	1193	else
954	next = min_next;	1194	NEXT (last_sent + send_interval);
		1195
		1196	printf ("pi %f si %f N %f (%d:%d)\n", poll_interval, send_interval, next - NOW, vpn->dns_sndpq.size (), snddq.size ());
955		1197
956	w.start (next);	1198	w.start (next);
957	}	1199	}
958		1200
959	#endif	1201	#endif

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs. Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs.
Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC