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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC vs.
Revision 1.38 by pcg, Tue Apr 19 04:23:38 2005 UTC

…		…
17	You should have received a copy of the GNU General Public License	17	You should have received a copy of the GNU General Public License
18	along with gvpe; if not, write to the Free Software	18	along with gvpe; if not, write to the Free Software
19	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA	19	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20	*/	20	*/
21		21
		22	// TODO: EDNS0 option to increase dns mtu?
		23	// TODO: re-write dns packet parsing/creation using a safe mem-buffer
		24	// to ensure no buffer overflows or similar problems.
		25
22	#include "config.h"	26	#include "config.h"
23		27
24	#if ENABLE_DNS	28	#if ENABLE_DNS
25		29
26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.	30	// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27	// it's a hack, use only in emergency situations please.	31	// it's a hack, use only in emergency situations please.
28		32
29	#include <cstring>	33	#include <cstring>
		34	#include <cassert>
30		35
31	#include <sys/types.h>	36	#include <sys/types.h>
32	#include <sys/socket.h>	37	#include <sys/socket.h>
33	#include <sys/wait.h>	38	#include <sys/wait.h>
34	#include <sys/uio.h>	39	#include <sys/uio.h>
…		…
43		48
44	#include "netcompat.h"	49	#include "netcompat.h"
45		50
46	#include "vpn.h"	51	#include "vpn.h"
47		52
48	#define MIN_POLL_INTERVAL .2 // how often to poll minimally when the server is having data
49	#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data	53	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
50	#define ACTIVITY_INTERVAL 5.	54	#define ACTIVITY_INTERVAL 5.
51		55
52	#define INITIAL_TIMEOUT 1.	56	#define INITIAL_TIMEOUT 0.1 // retry timeouts
53	#define INITIAL_SYN_TIMEOUT 2.	57	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54		58
55	#define MIN_SEND_INTERVAL (1./1000.)
56	#define MAX_SEND_INTERVAL 0.5 // optimistic?	59	#define MAX_SEND_INTERVAL 2. // optimistic?
57		60
58	#define MAX_OUTSTANDING 400 // max. outstanding requests
59	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	61	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
60	#define MAX_RATE 100 // requests/s
61	#define MAX_BACKLOG (100*1024) // size of protocol backlog, must be > MAXSIZE	62	#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
62		63
63	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	64	#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well
64	// 240 leaves about 4 bytes of server reply data	65	// 240 leaves about 4 bytes of server reply data
65	// every two request byte sless give room for one reply byte	66	// every request byte less give room for two reply bytes
66		67
67	#define SEQNO_MASK 0xffff	68	#define SEQNO_MASK 0x3fff
68	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	69	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
69		70
70	#define MAX_LBL_SIZE 63	71	#define MAX_LBL_SIZE 63
71	#define MAX_PKT_SIZE 512	72	#define MAX_PKT_SIZE 512
72		73
…		…
265	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	266	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
266		267
267	/////////////////////////////////////////////////////////////////////////////	268	/////////////////////////////////////////////////////////////////////////////
268		269
269	#define HDRSIZE 6	270	#define HDRSIZE 6
270		271
271	inline void encode_header (char *data, int clientid, int seqno)	272	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
272	{	273	{
273	u8 hdr[3] = { clientid, seqno >> 8, seqno };	274	seqno &= SEQNO_MASK;
		275
		276	u8 hdr[3] = {
		277	clientid,
		278	(seqno >> 8) \| (retry << 6),
		279	seqno,
		280	};
274		281
275	assert (clientid < 256);	282	assert (clientid < 256);
276		283
277	cdc26.encode (data, hdr, 3);	284	cdc26.encode (data, hdr, 3);
278	}	285	}
…		…
282	u8 hdr[3];	289	u8 hdr[3];
283		290
284	cdc26.decode (hdr, data, HDRSIZE);	291	cdc26.decode (hdr, data, HDRSIZE);
285		292
286	clientid = hdr[0];	293	clientid = hdr[0];
287	seqno = (hdr[1] << 8) \| hdr[2];	294	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
288	}	295	}
289		296
290	/////////////////////////////////////////////////////////////////////////////	297	/////////////////////////////////////////////////////////////////////////////
291		298
292	struct byte_stream	299	struct byte_stream
…		…
321	}	328	}
322		329
323	void byte_stream::remove (int count)	330	void byte_stream::remove (int count)
324	{	331	{
325	if (count > fill)	332	if (count > fill)
326	abort ();	333	assert (count <= fill);
327		334
328	memmove (data, data + count, fill -= count);	335	memmove (data, data + count, fill -= count);
329	}	336	}
330		337
331	bool byte_stream::put (u8 *data, unsigned int datalen)	338	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
351	return true;	358	return true;
352	}	359	}
353		360
354	vpn_packet *byte_stream::get ()	361	vpn_packet *byte_stream::get ()
355	{	362	{
		363	unsigned int len;
		364
		365	for (;;)
		366	{
356	int len = (data [0] << 8) \| data [1];	367	len = (data [0] << 8) \| data [1];
357		368
358	if (len > MAXSIZE && fill >= 2)	369	if (len <= MAXSIZE \|\| fill < 2)
359	abort (); // TODO handle this gracefully, connection reset	370	break;
360		371
		372	// TODO: handle this better than skipping, e.g. by reset
		373	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		374	remove (1);
		375	}
		376
361	if (fill < len + 2)	377	if (fill < len + 2)
362	return 0;	378	return 0;
363		379
364	vpn_packet *pkt = new vpn_packet;	380	vpn_packet *pkt = new vpn_packet;
365		381
…		…
394	struct dns_cfg	410	struct dns_cfg
395	{	411	{
396	static int next_uid;	412	static int next_uid;
397		413
398	u8 id1, id2, id3, id4;	414	u8 id1, id2, id3, id4;
		415
399	u8 version;	416	u8 version;
		417	u8 flags;
400	u8 rrtype;	418	u8 rrtype;
401	u8 flags;
402	u8 def_ttl;	419	u8 def_ttl;
403	u8 rcv_cdc;	420
404	u8 snd_cdc;
405	u16 max_size;
406	u16 client;	421	u16 client;
407	u16 uid; // to make request unique	422	u16 uid; // to make request unique
408		423
409	u8 reserved[8];	424	u16 max_size;
		425	u8 seq_cdc;
		426	u8 req_cdc;
		427
		428	u8 rep_cdc;
		429	u8 delay; // time in 0.01s units that the server may delay replying packets
		430	u8 r3, r4;
		431
		432	u8 r5, r6, r7, r8;
410		433
411	void reset (int clientid);	434	void reset (int clientid);
412	bool valid ();	435	bool valid ();
413	};	436	};
414		437
…		…
424	version = 1;	447	version = 1;
425		448
426	rrtype = RR_TYPE_TXT;	449	rrtype = RR_TYPE_TXT;
427	flags = 0;	450	flags = 0;
428	def_ttl = 0;	451	def_ttl = 0;
		452	seq_cdc = 26;
		453	req_cdc = 62;
429	rcv_cdc = 0;	454	rep_cdc = 0;
430	snd_cdc = 62;
431	max_size = ntohs (MAX_PKT_SIZE);	455	max_size = htons (MAX_PKT_SIZE);
432	client = ntohs (clientid);	456	client = htons (clientid);
433	uid = next_uid++;	457	uid = next_uid++;
		458	delay = 0;
434		459
435	memset (reserved, 0, 8);	460	r3 = r4 = 0;
		461	r4 = r5 = r6 = r7 = 0;
436	}	462	}
437		463
438	bool dns_cfg::valid ()	464	bool dns_cfg::valid ()
439	{	465	{
440	return id1 == 'G'	466	return id1 == 'G'
441	&& id2 == 'V'	467	&& id2 == 'V'
442	&& id3 == 'P'	468	&& id3 == 'P'
443	&& id4 == 'E'	469	&& id4 == 'E'
		470	&& seq_cdc == 26
		471	&& req_cdc == 62
		472	&& rep_cdc == 0
444	&& version == 1	473	&& version == 1;
445	&& flags == 0
446	&& rcv_cdc == 0
447	&& snd_cdc == 62
448	&& max_size == ntohs (MAX_PKT_SIZE);
449	}	474	}
450		475
451	struct dns_packet : net_packet	476	struct dns_packet : net_packet
452	{	477	{
453	u16 id;	478	u16 id;
454	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	479	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
455	u16 qdcount, ancount, nscount, arcount;	480	u16 qdcount, ancount, nscount, arcount;
456		481
457	u8 data[MAXSIZE - 6 * 2];	482	u8 data [MAXSIZE - 6 * 2];
458		483
459	int decode_label (char *data, int size, int &offs);	484	int decode_label (char *data, int size, int &offs);
460	};	485	};
461		486
462	int dns_packet::decode_label (char *data, int size, int &offs)	487	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
493	return data - orig;	518	return data - orig;
494	}	519	}
495		520
496	/////////////////////////////////////////////////////////////////////////////	521	/////////////////////////////////////////////////////////////////////////////
497		522
498	struct dns_snd
499	{
500	dns_packet *pkt;
501	tstamp timeout, sent;
502	int retry;
503	struct dns_connection *dns;
504	int seqno;
505
506	dns_snd (dns_connection *dns);
507	void gen_stream_req (int seqno, byte_stream &stream);
508	void gen_syn_req (const dns_cfg &cfg);
509	};
510
511	static u16 dns_id = 12098; // TODO: should be per-vpn	523	static u16 dns_id = 0; // TODO: should be per-vpn
512		524
513	static u16 next_id ()	525	static u16 next_id ()
514	{	526	{
		527	if (!dns_id)
		528	dns_id = time (0);
		529
515	// the simplest lsfr with periodicity 65535 i could find	530	// the simplest lsfr with periodicity 65535 i could find
516	dns_id = (dns_id << 1)	531	dns_id = (dns_id << 1)
517	\| (((dns_id >> 1)	532	\| (((dns_id >> 1)
518	^ (dns_id >> 2)	533	^ (dns_id >> 2)
519	^ (dns_id >> 4)	534	^ (dns_id >> 4)
520	^ (dns_id >> 15)) & 1);	535	^ (dns_id >> 15)) & 1);
521		536
522	return dns_id;	537	return dns_id;
523	}	538	}
524		539
		540	struct dns_rcv;
		541	struct dns_snd;
		542
		543	struct dns_connection
		544	{
		545	connection *c;
		546	struct vpn *vpn;
		547
		548	dns_cfg cfg;
		549
		550	bool established;
		551
		552	tstamp last_received;
		553	tstamp last_sent;
		554	double min_latency;
		555	double poll_interval, send_interval;
		556
		557	vector<dns_rcv *> rcvpq;
		558
		559	byte_stream rcvdq; int rcvseq; int repseq;
		560	byte_stream snddq; int sndseq;
		561
		562	void time_cb (time_watcher &w); time_watcher tw;
		563	void receive_rep (dns_rcv *r);
		564
		565	dns_connection (connection *c);
		566	~dns_connection ();
		567	};
		568
		569	struct dns_snd
		570	{
		571	dns_packet *pkt;
		572	tstamp timeout, sent;
		573	int retry;
		574	struct dns_connection *dns;
		575	int seqno;
		576	bool stdhdr;
		577
		578	void gen_stream_req (int seqno, byte_stream &stream);
		579	void gen_syn_req ();
		580
		581	dns_snd (dns_connection *dns);
		582	~dns_snd ();
		583	};
		584
525	dns_snd::dns_snd (dns_connection *dns)	585	dns_snd::dns_snd (dns_connection *dns)
526	: dns (dns)	586	: dns (dns)
527	{	587	{
528	timeout = 0;	588	timeout = 0;
529	retry = 0;	589	retry = 0;
530	seqno = 0;	590	seqno = 0;
		591	sent = NOW;
		592	stdhdr = false;
531		593
532	pkt = new dns_packet;	594	pkt = new dns_packet;
533		595
534	pkt->id = next_id ();	596	pkt->id = next_id ();
		597	}
		598
		599	dns_snd::~dns_snd ()
		600	{
		601	delete pkt;
535	}	602	}
536		603
537	static void append_domain (dns_packet &pkt, int &offs, const char *domain)	604	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
538	{	605	{
539	// add tunnel domain	606	// add tunnel domain
…		…
557	}	624	}
558	}	625	}
559		626
560	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)	627	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
561	{	628	{
		629	stdhdr = true;
562	this->seqno = seqno;	630	this->seqno = seqno;
563		631
564	timeout = NOW + INITIAL_TIMEOUT;	632	timeout = NOW + INITIAL_TIMEOUT;
565		633
566	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	634	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
567	pkt->qdcount = htons (1);	635	pkt->qdcount = htons (1);
568		636
569	int offs = 6*2;	637	int offs = 6*2;
570	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	638	int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
571	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	639	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
572	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra	640	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
573		641
574	char enc[256], *encp = enc;	642	char enc[256], *encp = enc;
575	encode_header (enc, THISNODE->id, seqno);	643	encode_header (enc, THISNODE->id, seqno);
…		…
593	encp += lbllen;	661	encp += lbllen;
594		662
595	enclen -= lbllen;	663	enclen -= lbllen;
596	}	664	}
597		665
598	append_domain (*pkt, offs, THISNODE->domain);	666	append_domain (*pkt, offs, dns->c->conf->domain);
599		667
600	(*pkt)[offs++] = 0;	668	(*pkt)[offs++] = 0;
601	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	669	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
602	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	670	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
603		671
604	pkt->len = offs;	672	pkt->len = offs;
605	}	673	}
606		674
607	void dns_snd::gen_syn_req (const dns_cfg &cfg)	675	void dns_snd::gen_syn_req ()
608	{	676	{
609	timeout = NOW + INITIAL_SYN_TIMEOUT;	677	timeout = NOW + INITIAL_SYN_TIMEOUT;
610		678
611	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	679	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
612	pkt->qdcount = htons (1);	680	pkt->qdcount = htons (1);
613		681
614	int offs = 6*2;	682	int offs = 6 * 2;
615		683
616	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));	684	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
617		685
618	assert (elen <= MAX_LBL_SIZE);	686	assert (elen <= MAX_LBL_SIZE);
619		687
620	(*pkt)[offs] = elen;	688	(*pkt)[offs] = elen;
621	offs += elen + 1;	689	offs += elen + 1;
622	append_domain (*pkt, offs, THISNODE->domain);	690	append_domain (*pkt, offs, dns->c->conf->domain);
623		691
624	(*pkt)[offs++] = 0;	692	(*pkt)[offs++] = 0;
625	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;	693	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
626	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	694	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
627		695
…		…
650	delete pkt;	718	delete pkt;
651	}	719	}
652		720
653	/////////////////////////////////////////////////////////////////////////////	721	/////////////////////////////////////////////////////////////////////////////
654		722
655	struct dns_connection
656	{
657	connection *c;
658	struct vpn *vpn;
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
668	vector<dns_rcv *> rcvpq;
669
670	byte_stream rcvdq; int rcvseq;
671	byte_stream snddq; int sndseq;
672
673	void time_cb (time_watcher &w); time_watcher tw;
674	void receive_rep (dns_rcv *r);
675
676	dns_connection (connection *c);
677	~dns_connection ();
678	};
679
680	dns_connection::dns_connection (connection *c)	723	dns_connection::dns_connection (connection *c)
681	: c (c)	724	: c (c)
682	, rcvdq (MAX_BACKLOG * 2)	725	, rcvdq (MAX_BACKLOG * 2)
683	, snddq (MAX_BACKLOG * 2)	726	, snddq (MAX_BACKLOG)
684	, tw (this, &dns_connection::time_cb)	727	, tw (this, &dns_connection::time_cb)
685	{	728	{
686	vpn = c->vpn;	729	vpn = c->vpn;
687		730
688	established = false;	731	established = false;
689		732
690	rcvseq = sndseq = 0;	733	rcvseq = repseq = sndseq = 0;
691		734
692	last_sent = last_received = 0;	735	last_sent = last_received = 0;
693	poll_interval = MIN_POLL_INTERVAL;	736	poll_interval = 0.5; // starting here
694	send_interval = 0.2; // starting rate	737	send_interval = 0.5; // starting rate
		738	min_latency = INITIAL_TIMEOUT;
695	}	739	}
696		740
697	dns_connection::~dns_connection ()	741	dns_connection::~dns_connection ()
698	{	742	{
699	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	743	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
…		…
707	if (r->datalen)	751	if (r->datalen)
708	{	752	{
709	last_received = NOW;	753	last_received = NOW;
710	tw.trigger ();	754	tw.trigger ();
711		755
712	poll_interval *= 0.99;	756	poll_interval = send_interval;
713	if (poll_interval > MIN_POLL_INTERVAL)
714	poll_interval = MIN_POLL_INTERVAL;
715	}	757	}
716	else	758	else
717	{	759	{
718	poll_interval *= 1.1;	760	poll_interval *= 1.5;
		761
719	if (poll_interval > MAX_POLL_INTERVAL)	762	if (poll_interval > MAX_POLL_INTERVAL)
720	poll_interval = MAX_POLL_INTERVAL;	763	poll_interval = MAX_POLL_INTERVAL;
721	}	764	}
722		765
723	rcvpq.push_back (r);	766	rcvpq.push_back (r);
…		…
741	}	784	}
742		785
743	rcvseq = (rcvseq + 1) & SEQNO_MASK;	786	rcvseq = (rcvseq + 1) & SEQNO_MASK;
744		787
745	if (!rcvdq.put (r->data, r->datalen))	788	if (!rcvdq.put (r->data, r->datalen))
		789	{
		790	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
746	abort (); // MUST never overflow, can be caused by data corruption, TODO	791	abort (); // MUST never overflow, can be caused by data corruption, TODO
		792	}
747		793
748	while (vpn_packet *pkt = rcvdq.get ())	794	while (vpn_packet *pkt = rcvdq.get ())
749	{	795	{
750	sockinfo si;	796	sockinfo si;
751	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	797	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
752		798
753	vpn->recv_vpn_packet (pkt, si);	799	vpn->recv_vpn_packet (pkt, si);
		800
		801	delete pkt;
754	}	802	}
755		803
756	// check for further packets	804	// check for further packets
757	goto redo;	805	goto redo;
758	}	806	}
…		…
768	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	816	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
769		817
770	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))	818	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
771	&& pkt.qdcount == htons (1))	819	&& pkt.qdcount == htons (1))
772	{	820	{
773	char qname[MAXSIZE];	821	char qname [MAXSIZE];
774	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);	822	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
775		823
776	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];	824	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
777	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];	825	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
778		826
779	pkt.qdcount = htons (1);	827	pkt.qdcount = htons (1);
780	pkt.ancount = 0;	828	pkt.ancount = 0;
781	pkt.nscount = 0; // should be self, as other nameservers reply like this	829	pkt.nscount = 0; // should be self, as other nameservers reply like this
782	pkt.arcount = 0; // a record for self, as other nameservers reply like this	830	pkt.arcount = 0; // a record for self, as other nameservers reply like this
783		831
784	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	832	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
785		833
786	int dlen = strlen (THISNODE->domain);	834	int dlen = strlen (THISNODE->domain);
787		835
788	if (qclass == RR_CLASS_IN	836	if (qclass == RR_CLASS_IN
789	&& qlen > dlen + 1	837	&& qlen > dlen + 1
790	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	838	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
791	{	839	{
792	// now generate reply	840	// now generate reply
793	pkt.ancount = htons (1); // one answer RR	841	pkt.ancount = htons (1); // one answer RR
794	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	842	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
795		843
…		…
817	if (SEQNO_EQ ((*i)->seqno, seqno))	865	if (SEQNO_EQ ((*i)->seqno, seqno))
818	{	866	{
819	// already seen that request: simply reply with the cached reply	867	// already seen that request: simply reply with the cached reply
820	dns_rcv r = i;	868	dns_rcv r = i;
821		869
822	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	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;
823		875
824	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);	876	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
825	pkt.id = r->pkt->id;	877
826	goto duplicate_request;	878	goto duplicate_request;
827	}	879	}
828		880
829	// new packet, queue	881	// new packet, queue
830	rcv = new dns_rcv (seqno, data, datalen);	882	rcv = new dns_rcv (seqno, data, datalen);
831	dns->receive_rep (rcv);	883	dns->receive_rep (rcv);
832	}	884	}
833		885
		886	{
834	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section	887	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
835		888
836	// type
837	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;	889	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
838	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype;	890	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
839
840	// class
841	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN;	891	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
842
843	// TTL
844	pkt [offs++] = 0; pkt [offs++] = 0;	892	pkt [offs++] = 0; pkt [offs++] = 0;
845	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0;	893	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
846		894
847	int rdlen_offs = offs += 2;	895	int rdlen_offs = offs += 2;
848		896
		897	if (dns)
		898	{
849	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;	899	int dlen = ntohs (dns->cfg.max_size) - offs;
		900
850	// bind doesn't compress well, so reduce further by one label length	901	// bind doesn't compress well, so reduce further by one label length
851	dlen -= qlen;	902	dlen -= qlen;
852		903
853	if (dns)	904	// only put data into in-order sequence packets, if
854	{	905	// we receive out-of-order packets we generate empty
855	while (dlen > 1 && !dns->snddq.empty ())	906	// replies
		907	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		908	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
856	{	909	{
		910	dns->repseq = seqno;
		911
		912	while (dlen > 1 && !dns->snddq.empty ())
		913	{
857	int txtlen = dlen <= 255 ? dlen - 1 : 255;	914	int txtlen = dlen <= 255 ? dlen - 1 : 255;
858		915
859	if (txtlen > dns->snddq.size ())	916	if (txtlen > dns->snddq.size ())
860	txtlen = dns->snddq.size ();	917	txtlen = dns->snddq.size ();
861		918
862	pkt[offs++] = txtlen;	919	pkt[offs++] = txtlen;
863	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);	920	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
864	offs += txtlen;	921	offs += txtlen;
865	dns->snddq.remove (txtlen);	922	dns->snddq.remove (txtlen);
866		923
867	dlen -= txtlen + 1;	924	dlen -= txtlen + 1;
		925	}
868	}	926	}
869		927
870	// avoid empty TXT rdata	928	// avoid completely empty TXT rdata
871	if (offs == rdlen_offs)	929	if (offs == rdlen_offs)
872	pkt[offs++] = 0;	930	pkt[offs++] = 0;
		931
		932	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
873	}	933	}
874	else	934	else
875	{	935	{
876	// send RST	936	// send RST
877	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	937	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
878	pkt [offs++] = CMD_IP_RST;	938	pkt [offs++] = CMD_IP_RST;
879	}	939	}
880		940
881	int rdlen = offs - rdlen_offs;	941	int rdlen = offs - rdlen_offs;
882		942
883	pkt [rdlen_offs - 2] = rdlen >> 8;	943	pkt [rdlen_offs - 2] = rdlen >> 8;
884	pkt [rdlen_offs - 1] = rdlen;	944	pkt [rdlen_offs - 1] = rdlen;
885		945
886	if (dns)	946	if (dns)
887	{	947	{
888	// now update dns_rcv copy	948	// now update dns_rcv copy
889	rcv->pkt->len = offs;	949	rcv->pkt->len = offs;
890	memcpy (rcv->pkt->at (0), pkt.at (0), offs);	950	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
891	}	951	}
		952	}
892		953
893	duplicate_request: ;	954	duplicate_request: ;
894	}	955	}
895	else	956	else
896	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	957	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
…		…
908	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	969	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
909	pkt [offs++] = 0; pkt [offs++] = 0;	970	pkt [offs++] = 0; pkt [offs++] = 0;
910	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL	971	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
911	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength	972	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
912		973
913	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);	974	slog (L_INFO, _("DNS: client %d connects"), client);
914		975
915	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	976	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
916	pkt [offs++] = CMD_IP_REJ;	977	pkt [offs++] = CMD_IP_REJ;
917		978
918	if (0 < client && client <= conns.size ())	979	if (0 < client && client <= conns.size ())
…		…
949	i != dns_sndpq.end ();	1010	i != dns_sndpq.end ();
950	++i)	1011	++i)
951	if ((*i)->pkt->id == pkt.id)	1012	if ((*i)->pkt->id == pkt.id)
952	{	1013	{
953	dns_connection dns = (i)->dns;	1014	dns_connection dns = (i)->dns;
		1015	connection *c = dns->c;
954	int seqno = (*i)->seqno;	1016	int seqno = (*i)->seqno;
955	u8 data[MAXSIZE], *datap = data;	1017	u8 data[MAXSIZE], *datap = data;
956		1018
957	if ((*i)->retry)	1019	if ((*i)->retry)
958	{	1020	{
959	dns->send_interval *= 1.01;	1021	dns->send_interval *= 1.01;
960	if (dns->send_interval < MAX_SEND_INTERVAL)	1022	if (dns->send_interval > MAX_SEND_INTERVAL)
961	dns->send_interval = MAX_SEND_INTERVAL;	1023	dns->send_interval = MAX_SEND_INTERVAL;
962	}	1024	}
963	else	1025	else
964	{	1026	{
		1027	#if 0
965	dns->send_interval *= 0.99;	1028	dns->send_interval *= 0.999;
966	if (dns->send_interval < MIN_SEND_INTERVAL)	1029	#endif
967	dns->send_interval = MIN_SEND_INTERVAL;
968
969	// the latency surely puts an upper bound on	1030	// the latency surely puts an upper bound on
970	// the minimum send interval	1031	// the minimum send interval
971	if (dns->send_interval > NOW - (*i)->sent)	1032	double latency = NOW - (*i)->sent;
972	dns->send_interval = NOW - (*i)->sent;	1033
		1034	if (latency < dns->min_latency)
		1035	dns->min_latency = latency;
		1036
		1037	if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
		1038	dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
		1039
		1040	if (dns->send_interval < conf.dns_send_interval)
		1041	dns->send_interval = conf.dns_send_interval;
973	}	1042	}
974		1043
975	delete *i;	1044	delete *i;
976	dns_sndpq.erase (i);	1045	dns_sndpq.erase (i);
977		1046
…		…
1027		1096
1028	if (ip [0] == CMD_IP_1	1097	if (ip [0] == CMD_IP_1
1029	&& ip [1] == CMD_IP_2	1098	&& ip [1] == CMD_IP_2
1030	&& ip [2] == CMD_IP_3)	1099	&& ip [2] == CMD_IP_3)
1031	{	1100	{
1032	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);	1101	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1033		1102
1034	if (ip [3] == CMD_IP_RST)	1103	if (ip [3] == CMD_IP_RST)
1035	{	1104	{
1036	slog (L_DEBUG, _("got tunnel RST request"));	1105	slog (L_DEBUG, _("DNS: got tunnel RST request"));
1037		1106
1038	connection *c = dns->c;
1039	delete c->dns; c->dns = 0;	1107	delete dns; c->dns = 0;
1040		1108
1041	return;	1109	return;
1042	}	1110	}
1043	else if (ip [3] == CMD_IP_SYN)	1111	else if (ip [3] == CMD_IP_SYN)
		1112	{
		1113	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1044	dns->established = true;	1114	dns->established = true;
		1115	}
		1116	else if (ip [3] == CMD_IP_REJ)
		1117	{
		1118	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1119	abort ();
		1120	}
1045	else	1121	else
1046	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);	1122	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1047	}	1123	}
1048	else	1124	else
1049	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),	1125	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1050	ip [0], ip [1], ip [2], ip [3]);	1126	ip [0], ip [1], ip [2], ip [3]);
1051		1127
1052	return;	1128	return;
1053	}	1129	}
1054		1130
1055	int client, rseqno;	1131	int client, rseqno;
1056	decode_header (qname, client, rseqno);	1132	decode_header (qname, client, rseqno);
1057		1133
1058	if (client != THISNODE->id)	1134	if (client != THISNODE->id)
1059	{	1135	{
1060	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));	1136	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1061	datap = 0;	1137	datap = 0;
1062	}	1138	}
1063	else if (rseqno != seqno)	1139	else if (rseqno != seqno)
1064	{	1140	{
1065	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));	1141	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
1066	datap = 0;	1142	datap = 0;
1067	}	1143	}
1068	}	1144	}
1069	}	1145	}
1070		1146
…		…
1087		1163
1088	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);	1164	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1089		1165
1090	if (pkt->len > 0)	1166	if (pkt->len > 0)
1091	{	1167	{
1092	if (THISNODE->dns_port)	1168	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1169	dnsv4_client (*pkt);
		1170	else
1093	{	1171	{
1094	dnsv4_server (*pkt);	1172	dnsv4_server (*pkt);
1095	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);	1173	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1096	}	1174	}
1097	else
1098	dnsv4_client (*pkt);
1099		1175
1100	delete pkt;	1176	delete pkt;
1101	}	1177	}
1102	}	1178	}
1103	}	1179	}
1104		1180
1105	bool	1181	bool
1106	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1182	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1107	{	1183	{
		1184	int client = ntohl (si.host);
		1185
		1186	assert (0 < client && client <= conns.size ());
		1187
		1188	connection *c = conns [client - 1];
		1189
1108	if (!dns)	1190	if (!c->dns)
1109	dns = new dns_connection (this);	1191	c->dns = new dns_connection (c);
1110		1192
1111	if (!dns->snddq.put (pkt))	1193	if (c->dns->snddq.put (pkt))
1112	return false;
1113
1114	dns->tw.trigger ();	1194	c->dns->tw.trigger ();
1115		1195
		1196	// always return true even if the buffer overflows
1116	return true;	1197	return true;
		1198	}
		1199
		1200	void
		1201	connection::dnsv4_reset_connection ()
		1202	{
		1203	//delete dns; dns = 0; //TODO
1117	}	1204	}
1118		1205
1119	#define NEXT(w) do { if (next > (w)) next = w; } while (0)	1206	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1120		1207
1121	void	1208	void
…		…
1140	if (!send)	1227	if (!send)
1141	{	1228	{
1142	send = r;	1229	send = r;
1143		1230
1144	r->retry++;	1231	r->retry++;
1145	r->timeout = NOW + r->retry;	1232	r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor);
		1233
		1234	// the following code changes the query section a bit, forcing
		1235	// the forwarder to generate a new request
		1236	if (r->stdhdr)
		1237	{
		1238	//printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
		1239	//encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
		1240	}
1146	}	1241	}
1147	}	1242	}
1148	else if (r->timeout < next)	1243	else
1149	NEXT (r->timeout);	1244	NEXT (r->timeout);
1150	}	1245	}
1151		1246
1152	if (last_sent + send_interval <= NOW)
1153	{
1154	if (!send)	1247	if (!send)
		1248	{
		1249	// generate a new packet, if wise
		1250
		1251	if (!established)
1155	{	1252	{
1156	// generate a new packet, if wise
1157
1158	if (!established)
1159	{
1160	if (vpn->dns_sndpq.empty ())	1253	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	}
1168	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
1169	{	1254	{
1170	send = new dns_snd (this);	1255	send = new dns_snd (this);
		1256
		1257	cfg.reset (THISNODE->id);
		1258	send->gen_syn_req ();
		1259	}
		1260	}
		1261	else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
		1262	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1263	{
		1264	if (last_sent + send_interval <= NOW)
		1265	{
		1266	//printf ("sending data request etc.\n"); //D
		1267	if (!snddq.empty () \|\| last_received + 1. > NOW)
		1268	{
		1269	poll_interval = send_interval;
		1270	NEXT (NOW + send_interval);
		1271	}
		1272
		1273	send = new dns_snd (this);
1171	send->gen_stream_req (sndseq, snddq);	1274	send->gen_stream_req (sndseq, snddq);
		1275	send->timeout = NOW + min_latency * conf.dns_timeout_factor;
1172		1276
1173	sndseq = (sndseq + 1) & SEQNO_MASK;	1277	sndseq = (sndseq + 1) & SEQNO_MASK;
1174	}	1278	}
1175		1279	else
1176	if (send)	1280	NEXT (last_sent + send_interval);
1177	vpn->dns_sndpq.push_back (send);
1178	}	1281	}
1179		1282
1180	if (send)	1283	if (send)
1181	{	1284	vpn->dns_sndpq.push_back (send);
1182	printf ("send pkt\n");	1285	}
		1286
		1287	if (send)
		1288	{
1183	last_sent = NOW;	1289	last_sent = NOW;
1184
1185	if (!send->retry)
1186	send->sent = NOW;
1187
1188	sendto (vpn->dnsv4_fd,	1290	sendto (vpn->dnsv4_fd,
1189	send->pkt->at (0), send->pkt->len, 0,	1291	send->pkt->at (0), send->pkt->len, 0,
1190	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1292	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1191	}
1192	}	1293	}
1193	else
1194	NEXT (last_sent + send_interval);
1195		1294
1196	printf ("pi %f si %f N %f (%d:%d)\n", poll_interval, send_interval, next - NOW, vpn->dns_sndpq.size (), snddq.size ());	1295	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1296	poll_interval, send_interval, next - NOW,
		1297	vpn->dns_sndpq.size (), snddq.size (),
		1298	rcvpq.size ());
		1299
		1300	// TODO: no idea when this happens, but when next < NOW, we have a problem
		1301	// doesn't seem to happen anymore
		1302	if (next < NOW + 0.001)
		1303	next = NOW + 0.1;
1197		1304
1198	w.start (next);	1305	w.start (next);
1199	}	1306	}
1200		1307
1201	#endif	1308	#endif

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC vs. Revision 1.38 by pcg, Tue Apr 19 04:23:38 2005 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC vs.
Revision 1.38 by pcg, Tue Apr 19 04:23:38 2005 UTC