[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 1.15 by pcg, Fri Mar 4 10:15:45 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 .02 // how often to poll minimally when the server has 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.
50		51
		52	#define INITIAL_TIMEOUT 1. // retry timeouts
		53	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
		54
		55	#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
		56	#define MAX_SEND_INTERVAL 0.5 // optimistic?
		57
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	58	#define MAX_OUTSTANDING 40 // max. outstanding requests
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	59	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING
53	#define MAX_RATE 100 // requests/s
54	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	60	#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55		61
56	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	62	#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	63	// 240 leaves about 4 bytes of server reply data
58	// every two request byte sless give room for one reply byte	64	// every two request bytes less give room for one reply byte
59		65
60	#define SEQNO_MASK 0xffff	66	#define SEQNO_MASK 0xffff
61	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	67	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
62		68
63	#define MAX_LBL_SIZE 63	69	#define MAX_LBL_SIZE 63
64	#define MAX_PKT_SIZE 512	70	#define MAX_PKT_SIZE 512
65		71
		72	#define RR_TYPE_A 1
		73	#define RR_TYPE_NULL 10
66	#define RR_TYPE_TXT 16	74	#define RR_TYPE_TXT 16
67	#define RR_TYPE_ANY 255	75	#define RR_TYPE_ANY 255
		76
68	#define RR_CLASS_IN 1	77	#define RR_CLASS_IN 1
		78
		79	#define CMD_IP_1 207
		80	#define CMD_IP_2 46
		81	#define CMD_IP_3 236
		82	#define CMD_IP_RST 29
		83	#define CMD_IP_SYN 113
		84	#define CMD_IP_REJ 32
69		85
70	// works for cmaps up to 255 (not 256!)	86	// works for cmaps up to 255 (not 256!)
71	struct charmap	87	struct charmap
72	{	88	{
73	enum { INVALID = (u8)255 };	89	enum { INVALID = (u8)255 };
…		…
153	return dec_len [len];	169	return dec_len [len];
154	}	170	}
155		171
156	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	172	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
157	{	173	{
158	if (!len)	174	if (!len \|\| len > MAX_DEC_LEN)
159	return 0;	175	return 0;
160		176
161	int elen = encode_len (len);	177	int elen = encode_len (len);
162		178
163	mp_limb_t m [MAX_LIMBS];	179	mp_limb_t m [MAX_LIMBS];
…		…
182	return elen;	198	return elen;
183	}	199	}
184		200
185	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	201	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
186	{	202	{
187	if (!len)	203	if (!len \|\| len > MAX_ENC_LEN)
188	return 0;	204	return 0;
189		205
190	u8 src_ [MAX_ENC_LEN];	206	u8 src_ [MAX_ENC_LEN];
191	unsigned int elen = 0;	207	unsigned int elen = 0;
192		208
…		…
239	}	255	}
240	abort ();	256	abort ();
241	}	257	}
242	#endif	258	#endif
243		259
244	// the following sequence has been crafted to	260	//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");	261	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
250	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	262	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	263	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
252	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	264	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
253		265
…		…
331	return false;	343	return false;
332		344
333	data [fill++] = pkt->len >> 8;	345	data [fill++] = pkt->len >> 8;
334	data [fill++] = pkt->len;	346	data [fill++] = pkt->len;
335		347
336	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	348	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
337		349
338	return true;	350	return true;
339	}	351	}
340		352
341	vpn_packet *byte_stream::get ()	353	vpn_packet *byte_stream::get ()
342	{	354	{
343	int len = (data [0] << 8) \| data [1];	355	unsigned int len = (data [0] << 8) \| data [1];
344		356
345	if (len > MAXSIZE && fill >= 2)	357	if (len > MAXSIZE && fill >= 2)
346	abort (); // TODO handle this gracefully, connection reset	358	abort (); // TODO handle this gracefully, connection reset
347		359
348	if (fill < len + 2)	360	if (fill < len + 2)
349	return 0;	361	return 0;
350		362
351	vpn_packet *pkt = new vpn_packet;	363	vpn_packet *pkt = new vpn_packet;
352		364
353	pkt->len = len;	365	pkt->len = len;
354	memcpy (&((*pkt)[0]), data + 2, len);	366	memcpy (pkt->at (0), data + 2, len);
355	remove (len + 2);	367	remove (len + 2);
356		368
357	return pkt;	369	return pkt;
358	}	370	}
359		371
…		…
376	#define FLAG_RCODE_REFUSED ( 5 << 0)	388	#define FLAG_RCODE_REFUSED ( 5 << 0)
377		389
378	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	390	#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)	391	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
380		392
		393	struct dns_cfg
		394	{
		395	static int next_uid;
		396
		397	u8 id1, id2, id3, id4;
		398	u8 version;
		399	u8 rrtype;
		400	u8 flags;
		401	u8 def_ttl;
		402	u8 rcv_cdc;
		403	u8 snd_cdc;
		404	u16 max_size;
		405	u16 client;
		406	u16 uid; // to make request unique
		407
		408	u8 reserved[8];
		409
		410	void reset (int clientid);
		411	bool valid ();
		412	};
		413
		414	int dns_cfg::next_uid;
		415
		416	void dns_cfg::reset (int clientid)
		417	{
		418	id1 = 'G';
		419	id2 = 'V';
		420	id3 = 'P';
		421	id4 = 'E';
		422
		423	version = 1;
		424
		425	rrtype = RR_TYPE_TXT;
		426	flags = 0;
		427	def_ttl = 0;
		428	rcv_cdc = 0;
		429	snd_cdc = 62;
		430	max_size = ntohs (MAX_PKT_SIZE);
		431	client = ntohs (clientid);
		432	uid = next_uid++;
		433
		434	memset (reserved, 0, 8);
		435	}
		436
		437	bool dns_cfg::valid ()
		438	{
		439	return id1 == 'G'
		440	&& id2 == 'V'
		441	&& id3 == 'P'
		442	&& id4 == 'E'
		443	&& version == 1
		444	&& flags == 0
		445	&& rcv_cdc == 0
		446	&& snd_cdc == 62
		447	&& max_size == ntohs (MAX_PKT_SIZE);
		448	}
		449
381	struct dns_packet : net_packet	450	struct dns_packet : net_packet
382	{	451	{
383	u16 id;	452	u16 id;
384	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	453	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
385	u16 qdcount, ancount, nscount, arcount;	454	u16 qdcount, ancount, nscount, arcount;
…		…
423	return data - orig;	492	return data - orig;
424	}	493	}
425		494
426	/////////////////////////////////////////////////////////////////////////////	495	/////////////////////////////////////////////////////////////////////////////
427		496
428	struct dns_req	497	struct dns_snd
429	{	498	{
430	dns_packet *pkt;	499	dns_packet *pkt;
431	tstamp next;	500	tstamp timeout, sent;
432	int retry;	501	int retry;
433	struct dns_connection *dns;	502	struct dns_connection *dns;
434	int seqno;	503	int seqno;
435		504
436	dns_req (dns_connection *dns);
437	void gen_stream_req (int seqno, byte_stream &stream);	505	void gen_stream_req (int seqno, byte_stream &stream);
		506	void gen_syn_req (const dns_cfg &cfg);
		507
		508	dns_snd (dns_connection *dns);
		509	~dns_snd ();
438	};	510	};
439		511
440	static u16 dns_id = 12098; // TODO: should be per-vpn	512	static u16 dns_id = 12098; // TODO: should be per-vpn
441		513
442	static u16 next_id ()	514	static u16 next_id ()
…		…
449	^ (dns_id >> 15)) & 1);	521	^ (dns_id >> 15)) & 1);
450		522
451	return dns_id;	523	return dns_id;
452	}	524	}
453		525
454	dns_req::dns_req (dns_connection *dns)	526	dns_snd::dns_snd (dns_connection *dns)
455	: dns (dns)	527	: dns (dns)
456	{	528	{
457	next = 0;	529	timeout = 0;
458	retry = 0;	530	retry = 0;
		531	seqno = 0;
		532	sent = NOW;
459		533
460	pkt = new dns_packet;	534	pkt = new dns_packet;
461		535
462	pkt->id = next_id ();	536	pkt->id = next_id ();
463	}	537	}
464		538
		539	dns_snd::~dns_snd ()
		540	{
		541	delete pkt;
		542	}
		543
		544	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		545	{
		546	// add tunnel domain
		547	for (;;)
		548	{
		549	const char *end = strchr (domain, '.');
		550
		551	if (!end)
		552	end = domain + strlen (domain);
		553
		554	int len = end - domain;
		555
		556	pkt [offs++] = len;
		557	memcpy (pkt.at (offs), domain, len);
		558	offs += len;
		559
		560	if (!*end)
		561	break;
		562
		563	domain = end + 1;
		564	}
		565	}
		566
465	void dns_req::gen_stream_req (int seqno, byte_stream &stream)	567	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
466	{	568	{
467	this->seqno = seqno;	569	this->seqno = seqno;
		570
		571	timeout = NOW + INITIAL_TIMEOUT;
468		572
469	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	573	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
470	pkt->qdcount = htons (1);	574	pkt->qdcount = htons (1);
471		575
472	int offs = 6*2;	576	int offs = 6*2;
…		…
496	encp += lbllen;	600	encp += lbllen;
497		601
498	enclen -= lbllen;	602	enclen -= lbllen;
499	}	603	}
500		604
501	const char *suffix = THISNODE->domain;	605	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		606
523	(*pkt)[offs++] = 0;	607	(*pkt)[offs++] = 0;
524	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	608	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		609	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		610
		611	pkt->len = offs;
		612	}
		613
		614	void dns_snd::gen_syn_req (const dns_cfg &cfg)
		615	{
		616	timeout = NOW + INITIAL_SYN_TIMEOUT;
		617
		618	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		619	pkt->qdcount = htons (1);
		620
		621	int offs = 6*2;
		622
		623	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));
		624
		625	assert (elen <= MAX_LBL_SIZE);
		626
		627	(*pkt)[offs] = elen;
		628	offs += elen + 1;
		629	append_domain (*pkt, offs, THISNODE->domain);
		630
		631	(*pkt)[offs++] = 0;
		632	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
525	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	633	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
526		634
527	pkt->len = offs;	635	pkt->len = offs;
528	}	636	}
529		637
…		…
554	struct dns_connection	662	struct dns_connection
555	{	663	{
556	connection *c;	664	connection *c;
557	struct vpn *vpn;	665	struct vpn *vpn;
558		666
		667	dns_cfg cfg;
		668
		669	bool established;
		670
		671	tstamp last_received;
		672	tstamp last_sent;
		673	double poll_interval, send_interval;
		674
559	vector<dns_rcv *> rcvpq;	675	vector<dns_rcv *> rcvpq;
560		676
561	int rcvseq;
562	int sndseq;
563
564	byte_stream rcvdq;	677	byte_stream rcvdq; int rcvseq;
565	byte_stream snddq;	678	byte_stream snddq; int sndseq;
566		679
567	void time_cb (time_watcher &w); time_watcher tw;	680	void time_cb (time_watcher &w); time_watcher tw;
568	void receive_rep (dns_rcv *r);	681	void receive_rep (dns_rcv *r);
569		682
570	dns_connection (connection *c);	683	dns_connection (connection *c);
…		…
577	, snddq (MAX_BACKLOG * 2)	690	, snddq (MAX_BACKLOG * 2)
578	, tw (this, &dns_connection::time_cb)	691	, tw (this, &dns_connection::time_cb)
579	{	692	{
580	vpn = c->vpn;	693	vpn = c->vpn;
581		694
		695	established = false;
		696
582	rcvseq = sndseq = 0;	697	rcvseq = sndseq = 0;
		698
		699	last_sent = last_received = 0;
		700	poll_interval = MIN_POLL_INTERVAL;
		701	send_interval = 0.2; // starting rate
583	}	702	}
584		703
585	dns_connection::~dns_connection ()	704	dns_connection::~dns_connection ()
586	{	705	{
587	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	706	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
588	i != rcvpq.end ();	707	i != rcvpq.end ();
589	++i)	708	++i)
590	delete *i;	709	delete *i;
591	}	710	}
592		711
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)	712	void dns_connection::receive_rep (dns_rcv *r)
603	{	713	{
		714	if (r->datalen)
		715	{
		716	last_received = NOW;
		717	tw.trigger ();
		718
		719	poll_interval = send_interval;
		720	}
		721	else
		722	{
		723	poll_interval *= 1.1;
		724	if (poll_interval > MAX_POLL_INTERVAL)
		725	poll_interval = MAX_POLL_INTERVAL;
		726	}
		727
604	rcvpq.push_back (r);	728	rcvpq.push_back (r);
605		729
606	redo:	730	redo:
607		731
608	// find next packet	732	// find next packet
…		…
630	{	754	{
631	sockinfo si;	755	sockinfo si;
632	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	756	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;
633		757
634	vpn->recv_vpn_packet (pkt, si);	758	vpn->recv_vpn_packet (pkt, si);
		759
		760	delete pkt;
635	}	761	}
636		762
637	// check for further packets	763	// check for further packets
638	goto redo;	764	goto redo;
639	}	765	}
640	}	766	}
641		767
642	dns_packet *	768	void
643	vpn::dnsv4_server (dns_packet *pkt)	769	vpn::dnsv4_server (dns_packet &pkt)
644	{	770	{
645	u16 flags = ntohs (pkt->flags);	771	u16 flags = ntohs (pkt.flags);
646		772
647	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
648	int offs = 6 * 2; // skip header	773	int offs = 6 * 2; // skip header
649		774
650	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	775	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
651		776
652	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	777	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
653	&& pkt->qdcount == htons (1))	778	&& pkt.qdcount == htons (1))
654	{	779	{
655	char qname[MAXSIZE];	780	char qname[MAXSIZE];
656	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	781	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
657		782
658	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	783	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
659	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	784	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
660		785
661	pkt->qdcount = htons (1);	786	pkt.qdcount = htons (1);
662	pkt->ancount = 0;	787	pkt.ancount = 0;
663	pkt->nscount = 0; // should be self, as other nameservers reply like this	788	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	789	pkt.arcount = 0; // a record for self, as other nameservers reply like this
665		790
666	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	791	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);
667		792
668	int dlen = strlen (THISNODE->domain);	793	int dlen = strlen (THISNODE->domain);
669		794
670	if (qclass == RR_CLASS_IN	795	if (qclass == RR_CLASS_IN
671	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
672	&& qlen > dlen + 1 + HDRSIZE	796	&& qlen > dlen + 1
673	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	797	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
674	{	798	{
675	// correct class, domain: parse	799	// now generate reply
676	int client, seqno;	800	pkt.ancount = htons (1); // one answer RR
677	decode_header (qname, client, seqno);	801	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
678		802
679	u8 data[MAXSIZE];	803	if ((qtype == RR_TYPE_ANY
680	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	804	\|\| qtype == RR_TYPE_TXT
681		805	\|\| qtype == RR_TYPE_NULL)
682	if (0 < client && client <= conns.size ())	806	&& qlen > dlen + 1 + HDRSIZE)
683	{	807	{
684	connection *c = conns [client - 1];	808	// correct class, domain: parse
		809	int client, seqno;
		810	decode_header (qname, client, seqno);
685		811
686	if (!c->dns)	812	u8 data[MAXSIZE];
687	c->dns = new dns_connection (c);	813	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
688		814
689	dns_connection *dns = c->dns;	815	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	{	816	{
		817	connection *c = conns [client - 1];
		818	dns_connection *dns = c->dns;
		819	dns_rcv *rcv;
		820
		821	if (dns)
		822	{
		823	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
		824	if (SEQNO_EQ ((*i)->seqno, seqno))
		825	{
		826	// already seen that request: simply reply with the cached reply
		827	dns_rcv r = i;
		828
		829	slog (L_DEBUG, "DUPLICATE %d\n", htons (r->pkt->id));
		830
		831	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		832	pkt.id = r->pkt->id;
		833	goto duplicate_request;
		834	}
		835
		836	// new packet, queue
		837	rcv = new dns_rcv (seqno, data, datalen);
		838	dns->receive_rep (rcv);
		839	}
		840
		841	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		842
		843	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		844	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		845	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		846	pkt [offs++] = 0; pkt [offs++] = 0;
		847	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
		848
		849	int rdlen_offs = offs += 2;
		850
		851	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
		852	// bind doesn't compress well, so reduce further by one label length
		853	dlen -= qlen;
		854
		855	if (dns)
		856	{
		857	while (dlen > 1 && !dns->snddq.empty ())
		858	{
730	int txtlen = dlen <= 255 ? dlen - 1 : 255;	859	int txtlen = dlen <= 255 ? dlen - 1 : 255;
731		860
732	if (txtlen > dns->snddq.size ())	861	if (txtlen > dns->snddq.size ())
733	txtlen = dns->snddq.size ();	862	txtlen = dns->snddq.size ();
734		863
735	(*pkt)[offs++] = txtlen;	864	pkt[offs++] = txtlen;
736	memcpy (pkt->at (offs), dns->snddq.begin (), txtlen);	865	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
737	offs += txtlen;	866	offs += txtlen;
738	dns->snddq.remove (txtlen);	867	dns->snddq.remove (txtlen);
739		868
740	dlen -= txtlen + 1;	869	dlen -= txtlen + 1;
		870	}
		871
		872	// avoid empty TXT rdata
		873	if (offs == rdlen_offs)
		874	pkt[offs++] = 0;
		875
		876	slog (L_NOISE, "snddq %d", dns->snddq.size ());
		877	}
		878	else
		879	{
		880	// send RST
		881	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		882	pkt [offs++] = CMD_IP_RST;
		883	}
		884
		885	int rdlen = offs - rdlen_offs;
		886
		887	pkt [rdlen_offs - 2] = rdlen >> 8;
		888	pkt [rdlen_offs - 1] = rdlen;
		889
		890	if (dns)
		891	{
		892	// now update dns_rcv copy
		893	rcv->pkt->len = offs;
		894	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		895	}
		896
		897	duplicate_request: ;
741	}	898	}
742		899	else
743	// avoid empty TXT rdata	900	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	}	901	}
758	else	902	else if (qtype == RR_TYPE_A
759	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	903	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		904	{
		905	dns_cfg cfg;
		906	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		907	int client = ntohs (cfg.client);
		908
		909	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		910
		911	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
		912	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		913	pkt [offs++] = 0; pkt [offs++] = 0;
		914	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		915	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
		916
		917	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);
		918
		919	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		920	pkt [offs++] = CMD_IP_REJ;
		921
		922	if (0 < client && client <= conns.size ())
		923	{
		924	connection *c = conns [client - 1];
		925
		926	if (cfg.valid ())
		927	{
		928	pkt [offs - 1] = CMD_IP_SYN;
		929
		930	delete c->dns;
		931	c->dns = new dns_connection (c);
		932	c->dns->cfg = cfg;
		933	}
		934	}
		935	}
760	}	936	}
761		937
762	pkt->len = offs;	938	pkt.len = offs;
763	}	939	}
764
765	return pkt;
766	}	940	}
767		941
768	void	942	void
769	vpn::dnsv4_client (dns_packet *pkt)	943	vpn::dnsv4_client (dns_packet &pkt)
770	{	944	{
771	u16 flags = ntohs (pkt->flags);	945	u16 flags = ntohs (pkt.flags);
772	int offs = 6 * 2; // skip header	946	int offs = 6 * 2; // skip header
773		947
774	pkt->qdcount = ntohs (pkt->qdcount);	948	pkt.qdcount = ntohs (pkt.qdcount);
775	pkt->ancount = ntohs (pkt->ancount);	949	pkt.ancount = ntohs (pkt.ancount);
776		950
777	// go through our request list and find the corresponding request	951	// go through our request list and find the corresponding request
778	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	952	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
779	i != dns_sndpq.end ();	953	i != dns_sndpq.end ();
780	++i)	954	++i)
781	if ((*i)->pkt->id == pkt->id)	955	if ((*i)->pkt->id == pkt.id)
782	{	956	{
783	dns_connection dns = (i)->dns;	957	dns_connection dns = (i)->dns;
		958	connection *c = dns->c;
784	int seqno = (*i)->seqno;	959	int seqno = (*i)->seqno;
785	u8 data[MAXSIZE], *datap = data;	960	u8 data[MAXSIZE], *datap = data;
786		961
		962	if ((*i)->retry)
		963	{
		964	dns->send_interval *= 1.001;
		965	if (dns->send_interval > MAX_SEND_INTERVAL)
		966	dns->send_interval = MAX_SEND_INTERVAL;
		967	}
		968	else
		969	{
		970	#if 1
		971	dns->send_interval *= 0.9999;
		972	#endif
		973	if (dns->send_interval < MIN_SEND_INTERVAL)
		974	dns->send_interval = MIN_SEND_INTERVAL;
		975
		976	// the latency surely puts an upper bound on
		977	// the minimum send interval
		978	double latency = NOW - (*i)->sent;
		979
		980	if (dns->send_interval > latency)
		981	dns->send_interval = latency;
		982	}
		983
787	delete *i;	984	delete *i;
788	dns_sndpq.erase (i);	985	dns_sndpq.erase (i);
789		986
790	if (flags & FLAG_RESPONSE && !(flags & (FLAG_OP_MASK \| FLAG_TC)))	987	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
791	{	988	{
792	char qname[MAXSIZE];	989	char qname[MAXSIZE];
793		990
794	while (pkt->qdcount-- && offs < MAXSIZE - 4)	991	while (pkt.qdcount-- && offs < MAXSIZE - 4)
795	{	992	{
796	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	993	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
797	offs += 4; // skip qtype, qclass	994	offs += 4; // skip qtype, qclass
798	}	995	}
799		996
800	while (pkt->ancount-- && offs < MAXSIZE - 10 && datap)	997	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
801	{	998	{
802	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	999	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
803		1000
804	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1001	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
805	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1002	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
806	u32 ttl = (*pkt) [offs++] << 24;	1003	u32 ttl = pkt [offs++] << 24;
807	ttl \|= (*pkt) [offs++] << 16;	1004	ttl \|= pkt [offs++] << 16;
808	ttl \|= (*pkt) [offs++] << 8;	1005	ttl \|= pkt [offs++] << 8;
809	ttl \|= (*pkt) [offs++];	1006	ttl \|= pkt [offs++];
810
811	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1007	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
812		1008
813	if (rdlen <= MAXSIZE - offs)	1009	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
814	{	1010	{
815	// decode bytes, finally	1011	if (rdlen <= MAXSIZE - offs)
816
817	while (rdlen)
818	{	1012	{
		1013	// decode bytes, finally
		1014
		1015	while (rdlen)
		1016	{
819	int txtlen = (*pkt) [offs++];	1017	int txtlen = pkt [offs++];
820		1018
821	assert (txtlen + offs < MAXSIZE - 1);	1019	assert (txtlen + offs < MAXSIZE - 1);
822		1020
823	memcpy (datap, pkt->at (offs), txtlen);	1021	memcpy (datap, pkt.at (offs), txtlen);
824	datap += txtlen; offs += txtlen;	1022	datap += txtlen; offs += txtlen;
825		1023
826	rdlen -= txtlen + 1;	1024	rdlen -= txtlen + 1;
		1025	}
827	}	1026	}
		1027	}
		1028	else if (qtype == RR_TYPE_A)
		1029	{
		1030	u8 ip [4];
		1031
		1032	ip [0] = pkt [offs++];
		1033	ip [1] = pkt [offs++];
		1034	ip [2] = pkt [offs++];
		1035	ip [3] = pkt [offs++];
		1036
		1037	if (ip [0] == CMD_IP_1
		1038	&& ip [1] == CMD_IP_2
		1039	&& ip [2] == CMD_IP_3)
		1040	{
		1041	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);
		1042
		1043	if (ip [3] == CMD_IP_RST)
		1044	{
		1045	slog (L_DEBUG, _("got tunnel RST request"));
		1046
		1047	delete dns; c->dns = 0;
		1048
		1049	return;
		1050	}
		1051	else if (ip [3] == CMD_IP_SYN)
		1052	{
		1053	slog (L_DEBUG, _("got tunnel SYN reply, server likes us."));
		1054	dns->established = true;
		1055	}
		1056	else if (ip [3] == CMD_IP_REJ)
		1057	{
		1058	slog (L_DEBUG, _("got tunnel REJ reply, server does not like us, aborting."));
		1059	abort ();
		1060	}
		1061	else
		1062	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);
		1063	}
		1064	else
		1065	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),
		1066	ip [0], ip [1], ip [2], ip [3]);
		1067
		1068	return;
828	}	1069	}
829		1070
830	int client, rseqno;	1071	int client, rseqno;
831	decode_header (qname, client, rseqno);	1072	decode_header (qname, client, rseqno);
832		1073
…		…
847	if (datap)	1088	if (datap)
848	dns->receive_rep (new dns_rcv (seqno, data, datap - data));	1089	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
849		1090
850	break;	1091	break;
851	}	1092	}
852
853	delete pkt;
854	}	1093	}
855		1094
856	void	1095	void
857	vpn::dnsv4_ev (io_watcher &w, short revents)	1096	vpn::dnsv4_ev (io_watcher &w, short revents)
858	{	1097	{
…		…
860	{	1099	{
861	dns_packet *pkt = new dns_packet;	1100	dns_packet *pkt = new dns_packet;
862	struct sockaddr_in sa;	1101	struct sockaddr_in sa;
863	socklen_t sa_len = sizeof (sa);	1102	socklen_t sa_len = sizeof (sa);
864		1103
865	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1104	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
866		1105
867	if (pkt->len > 0)	1106	if (pkt->len > 0)
868	{	1107	{
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)	1108	if (THISNODE->dns_port)
876	{	1109	{
877	pkt = dnsv4_server (pkt);	1110	dnsv4_server (*pkt);
878	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);	1111	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
879	}	1112	}
880	else	1113	else
881	dnsv4_client (pkt);	1114	dnsv4_client (*pkt);
		1115
		1116	delete pkt;
882	}	1117	}
883	}	1118	}
884	}	1119	}
885		1120
886	bool	1121	bool
…		…
890	dns = new dns_connection (this);	1125	dns = new dns_connection (this);
891		1126
892	if (!dns->snddq.put (pkt))	1127	if (!dns->snddq.put (pkt))
893	return false;	1128	return false;
894		1129
895	// start timer if neccessary
896	if (!THISNODE->dns_port && !dns->tw.active)
897	dns->tw.trigger ();	1130	dns->tw.trigger ();
898		1131
899	return true;	1132	return true;
900	}	1133	}
		1134
		1135	void
		1136	connection::dnsv4_reset_connection ()
		1137	{
		1138	//delete dns; dns = 0; //TODO
		1139	}
		1140
		1141	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
901		1142
902	void	1143	void
903	dns_connection::time_cb (time_watcher &w)	1144	dns_connection::time_cb (time_watcher &w)
904	{	1145	{
		1146	// servers have to be polled
		1147	if (THISNODE->dns_port)
		1148	return;
		1149
905	// check for timeouts and (re)transmit	1150	// check for timeouts and (re)transmit
906	tstamp next = NOW + 60;	1151	tstamp next = NOW + poll_interval;
907	dns_req *send = 0;	1152	dns_snd *send = 0;
908		1153
909	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1154	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
910	i != vpn->dns_sndpq.end ();	1155	i != vpn->dns_sndpq.end ();
911	++i)	1156	++i)
912	{	1157	{
913	dns_req r = i;	1158	dns_snd r = i;
914		1159
915	if (r->next <= NOW)	1160	if (r->timeout <= NOW)
916	{	1161	{
917	if (!send)	1162	if (!send)
918	{	1163	{
919	send = r;	1164	send = r;
920		1165
921	if (r->retry)//D
922	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
923	r->retry++;	1166	r->retry++;
924	r->next = NOW + r->retry;	1167	r->timeout = NOW + r->retry;
925	}	1168	}
926	}	1169	}
		1170	else
		1171	NEXT (r->timeout);
		1172	}
927		1173
928	if (r->next < next)	1174	if (last_sent + send_interval <= NOW)
929	next = r->next;
930	}	1175	{
931
932	if (!send	1176	if (!send)
		1177	{
		1178	// generate a new packet, if wise
		1179
		1180	if (!established)
		1181	{
		1182	if (vpn->dns_sndpq.empty ())
		1183	{
		1184	send = new dns_snd (this);
		1185
		1186	cfg.reset (THISNODE->id);
		1187	send->gen_syn_req (cfg);
		1188	}
		1189	}
933	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)	1190	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
934	{	1191	{
935	send = new dns_req (this);	1192	send = new dns_snd (this);
936	send->gen_stream_req (sndseq, snddq);	1193	send->gen_stream_req (sndseq, snddq);
		1194
		1195	sndseq = (sndseq + 1) & SEQNO_MASK;
		1196	}
		1197
		1198	if (send)
937	vpn->dns_sndpq.push_back (send);	1199	vpn->dns_sndpq.push_back (send);
		1200	}
938		1201
939	sndseq = (sndseq + 1) & SEQNO_MASK;
940	}
941
942	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
943
944	if (send)	1202	if (send)
945	{	1203	{
946	dns_packet *pkt = send->pkt;	1204	last_sent = NOW;
947		1205	sendto (vpn->dnsv4_fd,
948	next = min_next;	1206	send->pkt->at (0), send->pkt->len, 0,
949
950	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0,
951	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1207	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
		1208	}
952	}	1209	}
953	else if (next < min_next)	1210	else
954	next = min_next;	1211	NEXT (last_sent + send_interval);
		1212
		1213	slog (L_NOISE, "pi %f si %f N %f (%d:%d)",
		1214	poll_interval, send_interval, next - NOW,
		1215	vpn->dns_sndpq.size (), snddq.size ());
		1216
		1217	// TODO: no idea when this happens, but when next < NOW, we have a problem
		1218	if (next < NOW + 0.0001)
		1219	next = NOW + 0.1;
955		1220
956	w.start (next);	1221	w.start (next);
957	}	1222	}
958		1223
959	#endif	1224	#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 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC

Diff Legend

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs.
Revision 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC