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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.11 by pcg, Fri Mar 4 08:45:24 2005 UTC vs.
Revision 1.43 by pcg, Sat Dec 1 23:35:31 2007 UTC

…		…
14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15	GNU General Public License for more details.	15	GNU General Public License for more details.
16		16
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. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20	*/	20	*/
		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.
21		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 0.001
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_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
61		63
62	#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
63	// 240 leaves about 4 bytes of server reply data	65	// 240 leaves about 4 bytes of server reply data
64	// every two request byte sless give room for one reply byte	66	// every request byte less give room for two reply bytes
65		67
66	#define SEQNO_MASK 0xffff	68	#define SEQNO_MASK 0x3fff
67	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	69	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
68		70
69	#define MAX_LBL_SIZE 63	71	#define MAX_LBL_SIZE 63
70	#define MAX_PKT_SIZE 512	72	#define MAX_PKT_SIZE 512
71		73
…		…
264	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	266	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
265		267
266	/////////////////////////////////////////////////////////////////////////////	268	/////////////////////////////////////////////////////////////////////////////
267		269
268	#define HDRSIZE 6	270	#define HDRSIZE 6
269		271
270	inline void encode_header (char *data, int clientid, int seqno)	272	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
271	{	273	{
272	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	};
273		281
274	assert (clientid < 256);	282	assert (clientid < 256);
275		283
276	cdc26.encode (data, hdr, 3);	284	cdc26.encode (data, hdr, 3);
277	}	285	}
…		…
281	u8 hdr[3];	289	u8 hdr[3];
282		290
283	cdc26.decode (hdr, data, HDRSIZE);	291	cdc26.decode (hdr, data, HDRSIZE);
284		292
285	clientid = hdr[0];	293	clientid = hdr[0];
286	seqno = (hdr[1] << 8) \| hdr[2];	294	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
287	}	295	}
288		296
289	/////////////////////////////////////////////////////////////////////////////	297	/////////////////////////////////////////////////////////////////////////////
290		298
291	struct byte_stream	299	struct byte_stream
…		…
320	}	328	}
321		329
322	void byte_stream::remove (int count)	330	void byte_stream::remove (int count)
323	{	331	{
324	if (count > fill)	332	if (count > fill)
325	abort ();	333	assert (count <= fill);
326		334
327	memmove (data, data + count, fill -= count);	335	memmove (data, data + count, fill -= count);
328	}	336	}
329		337
330	bool byte_stream::put (u8 *data, unsigned int datalen)	338	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
350	return true;	358	return true;
351	}	359	}
352		360
353	vpn_packet *byte_stream::get ()	361	vpn_packet *byte_stream::get ()
354	{	362	{
		363	unsigned int len;
		364
		365	for (;;)
		366	{
355	int len = (data [0] << 8) \| data [1];	367	len = (data [0] << 8) \| data [1];
356		368
357	if (len > MAXSIZE && fill >= 2)	369	if (len <= MAXSIZE \|\| fill < 2)
358	abort (); // TODO handle this gracefully, connection reset	370	break;
359		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
360	if (fill < len + 2)	377	if (fill < len + 2)
361	return 0;	378	return 0;
362		379
363	vpn_packet *pkt = new vpn_packet;	380	vpn_packet *pkt = new vpn_packet;
364		381
…		…
393	struct dns_cfg	410	struct dns_cfg
394	{	411	{
395	static int next_uid;	412	static int next_uid;
396		413
397	u8 id1, id2, id3, id4;	414	u8 id1, id2, id3, id4;
		415
398	u8 version;	416	u8 version;
		417	u8 flags;
399	u8 rrtype;	418	u8 rrtype;
400	u8 flags;
401	u8 def_ttl;	419	u8 def_ttl;
402	u8 rcv_cdc;	420
403	u8 snd_cdc;
404	u16 max_size;
405	u16 client;	421	u16 client;
406	u16 uid; // to make request unique	422	u16 uid; // to make request unique
407		423
408	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;
409		433
410	void reset (int clientid);	434	void reset (int clientid);
411	bool valid ();	435	bool valid ();
412	};	436	};
413		437
…		…
423	version = 1;	447	version = 1;
424		448
425	rrtype = RR_TYPE_TXT;	449	rrtype = RR_TYPE_TXT;
426	flags = 0;	450	flags = 0;
427	def_ttl = 0;	451	def_ttl = 0;
		452	seq_cdc = 26;
		453	req_cdc = 62;
428	rcv_cdc = 0;	454	rep_cdc = 0;
429	snd_cdc = 62;
430	max_size = ntohs (MAX_PKT_SIZE);	455	max_size = htons (MAX_PKT_SIZE);
431	client = ntohs (clientid);	456	client = htons (clientid);
432	uid = next_uid++;	457	uid = next_uid++;
		458	delay = 0;
433		459
434	memset (reserved, 0, 8);	460	r3 = r4 = 0;
		461	r4 = r5 = r6 = r7 = 0;
435	}	462	}
436		463
437	bool dns_cfg::valid ()	464	bool dns_cfg::valid ()
438	{	465	{
		466	// although the protocol itself allows for some configurability,
		467	// only the following encoding/decoding settings are implemented.
439	return id1 == 'G'	468	return id1 == 'G'
440	&& id2 == 'V'	469	&& id2 == 'V'
441	&& id3 == 'P'	470	&& id3 == 'P'
442	&& id4 == 'E'	471	&& id4 == 'E'
		472	&& seq_cdc == 26
		473	&& req_cdc == 62
		474	&& rep_cdc == 0
443	&& version == 1	475	&& version == 1;
444	&& flags == 0
445	&& rcv_cdc == 0
446	&& snd_cdc == 62
447	&& max_size == ntohs (MAX_PKT_SIZE);
448	}	476	}
449		477
450	struct dns_packet : net_packet	478	struct dns_packet : net_packet
451	{	479	{
452	u16 id;	480	u16 id;
453	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	481	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
454	u16 qdcount, ancount, nscount, arcount;	482	u16 qdcount, ancount, nscount, arcount;
455		483
456	u8 data[MAXSIZE - 6 * 2];	484	u8 data [MAXSIZE - 6 * 2];
457		485
458	int decode_label (char *data, int size, int &offs);	486	int decode_label (char *data, int size, int &offs);
459	};	487	};
460		488
461	int dns_packet::decode_label (char *data, int size, int &offs)	489	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
492	return data - orig;	520	return data - orig;
493	}	521	}
494		522
495	/////////////////////////////////////////////////////////////////////////////	523	/////////////////////////////////////////////////////////////////////////////
496		524
497	struct dns_snd
498	{
499	dns_packet *pkt;
500	tstamp timeout, sent;
501	int retry;
502	struct dns_connection *dns;
503	int seqno;
504
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 ();
510	};
511
512	static u16 dns_id = 12098; // TODO: should be per-vpn	525	static u16 dns_id = 0; // TODO: should be per-vpn
513		526
514	static u16 next_id ()	527	static u16 next_id ()
515	{	528	{
		529	if (!dns_id)
		530	dns_id = time (0);
		531
516	// the simplest lsfr with periodicity 65535 i could find	532	// the simplest lsfr with periodicity 65535 i could find
517	dns_id = (dns_id << 1)	533	dns_id = (dns_id << 1)
518	\| (((dns_id >> 1)	534	\| (((dns_id >> 1)
519	^ (dns_id >> 2)	535	^ (dns_id >> 2)
520	^ (dns_id >> 4)	536	^ (dns_id >> 4)
521	^ (dns_id >> 15)) & 1);	537	^ (dns_id >> 15)) & 1);
522		538
523	return dns_id;	539	return dns_id;
524	}	540	}
525		541
		542	struct dns_rcv;
		543	struct dns_snd;
		544
		545	struct dns_connection
		546	{
		547	connection *c;
		548	struct vpn *vpn;
		549
		550	dns_cfg cfg;
		551
		552	bool established;
		553
		554	tstamp last_received;
		555	tstamp last_sent;
		556	double min_latency;
		557	double poll_interval, send_interval;
		558
		559	vector<dns_rcv *> rcvpq;
		560
		561	byte_stream rcvdq; int rcvseq; int repseq;
		562	byte_stream snddq; int sndseq;
		563
		564	void time_cb (ev::timer &w, int revents); ev::timer tw;
		565	void receive_rep (dns_rcv *r);
		566
		567	dns_connection (connection *c);
		568	~dns_connection ();
		569	};
		570
		571	struct dns_snd
		572	{
		573	dns_packet *pkt;
		574	tstamp timeout, sent;
		575	int retry;
		576	struct dns_connection *dns;
		577	int seqno;
		578	bool stdhdr;
		579
		580	void gen_stream_req (int seqno, byte_stream &stream);
		581	void gen_syn_req ();
		582
		583	dns_snd (dns_connection *dns);
		584	~dns_snd ();
		585	};
		586
526	dns_snd::dns_snd (dns_connection *dns)	587	dns_snd::dns_snd (dns_connection *dns)
527	: dns (dns)	588	: dns (dns)
528	{	589	{
529	timeout = 0;	590	timeout = 0;
530	retry = 0;	591	retry = 0;
531	seqno = 0;	592	seqno = 0;
532	sent = NOW;	593	sent = ev_now ();
		594	stdhdr = false;
533		595
534	pkt = new dns_packet;	596	pkt = new dns_packet;
535		597
536	pkt->id = next_id ();	598	pkt->id = next_id ();
537	}	599	}
…		…
564	}	626	}
565	}	627	}
566		628
567	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)	629	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
568	{	630	{
		631	stdhdr = true;
569	this->seqno = seqno;	632	this->seqno = seqno;
570		633
571	timeout = NOW + INITIAL_TIMEOUT;	634	timeout = ev_now () + INITIAL_TIMEOUT;
572		635
573	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	636	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
574	pkt->qdcount = htons (1);	637	pkt->qdcount = htons (1);
575		638
576	int offs = 6*2;	639	int offs = 6*2;
577	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	640	int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
578	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	641	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
579	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra	642	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
580		643
581	char enc[256], *encp = enc;	644	char enc[256], *encp = enc;
582	encode_header (enc, THISNODE->id, seqno);	645	encode_header (enc, THISNODE->id, seqno);
…		…
600	encp += lbllen;	663	encp += lbllen;
601		664
602	enclen -= lbllen;	665	enclen -= lbllen;
603	}	666	}
604		667
605	append_domain (*pkt, offs, THISNODE->domain);	668	append_domain (*pkt, offs, dns->c->conf->domain);
606		669
607	(*pkt)[offs++] = 0;	670	(*pkt)[offs++] = 0;
608	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	671	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
609	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	672	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
610		673
611	pkt->len = offs;	674	pkt->len = offs;
612	}	675	}
613		676
614	void dns_snd::gen_syn_req (const dns_cfg &cfg)	677	void dns_snd::gen_syn_req ()
615	{	678	{
616	timeout = NOW + INITIAL_SYN_TIMEOUT;	679	timeout = ev_now () + INITIAL_SYN_TIMEOUT;
617		680
618	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	681	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
619	pkt->qdcount = htons (1);	682	pkt->qdcount = htons (1);
620		683
621	int offs = 6*2;	684	int offs = 6 * 2;
622		685
623	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));	686	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
624		687
625	assert (elen <= MAX_LBL_SIZE);	688	assert (elen <= MAX_LBL_SIZE);
626		689
627	(*pkt)[offs] = elen;	690	(*pkt)[offs] = elen;
628	offs += elen + 1;	691	offs += elen + 1;
629	append_domain (*pkt, offs, THISNODE->domain);	692	append_domain (*pkt, offs, dns->c->conf->domain);
630		693
631	(*pkt)[offs++] = 0;	694	(*pkt)[offs++] = 0;
632	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;	695	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
633	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	696	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
634		697
…		…
657	delete pkt;	720	delete pkt;
658	}	721	}
659		722
660	/////////////////////////////////////////////////////////////////////////////	723	/////////////////////////////////////////////////////////////////////////////
661		724
662	struct dns_connection
663	{
664	connection *c;
665	struct vpn *vpn;
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
675	vector<dns_rcv *> rcvpq;
676
677	byte_stream rcvdq; int rcvseq;
678	byte_stream snddq; int sndseq;
679
680	void time_cb (time_watcher &w); time_watcher tw;
681	void receive_rep (dns_rcv *r);
682
683	dns_connection (connection *c);
684	~dns_connection ();
685	};
686
687	dns_connection::dns_connection (connection *c)	725	dns_connection::dns_connection (connection *c)
688	: c (c)	726	: c (c)
689	, rcvdq (MAX_BACKLOG * 2)	727	, rcvdq (MAX_BACKLOG * 2)
690	, snddq (MAX_BACKLOG * 2)	728	, snddq (MAX_BACKLOG)
691	, tw (this, &dns_connection::time_cb)	729	, tw (this, &dns_connection::time_cb)
692	{	730	{
693	vpn = c->vpn;	731	vpn = c->vpn;
694		732
695	established = false;	733	established = false;
696		734
697	rcvseq = sndseq = 0;	735	rcvseq = repseq = sndseq = 0;
698		736
699	last_sent = last_received = 0;	737	last_sent = last_received = 0;
700	poll_interval = MIN_POLL_INTERVAL;	738	poll_interval = 0.5; // starting here
701	send_interval = 0.2; // starting rate	739	send_interval = 0.5; // starting rate
		740	min_latency = INITIAL_TIMEOUT;
702	}	741	}
703		742
704	dns_connection::~dns_connection ()	743	dns_connection::~dns_connection ()
705	{	744	{
706	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	745	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
…		…
711		750
712	void dns_connection::receive_rep (dns_rcv *r)	751	void dns_connection::receive_rep (dns_rcv *r)
713	{	752	{
714	if (r->datalen)	753	if (r->datalen)
715	{	754	{
716	last_received = NOW;	755	last_received = ev_now ();
717	tw.trigger ();	756	tw ();
718		757
719	poll_interval *= 0.99;	758	poll_interval = send_interval;
720	if (poll_interval > MIN_POLL_INTERVAL)
721	poll_interval = MIN_POLL_INTERVAL;
722	}	759	}
723	else	760	else
724	{	761	{
725	poll_interval *= 1.1;	762	poll_interval *= 1.5;
		763
726	if (poll_interval > MAX_POLL_INTERVAL)	764	if (poll_interval > MAX_POLL_INTERVAL)
727	poll_interval = MAX_POLL_INTERVAL;	765	poll_interval = MAX_POLL_INTERVAL;
728	}	766	}
729		767
730	rcvpq.push_back (r);	768	rcvpq.push_back (r);
…		…
733		771
734	// find next packet	772	// find next packet
735	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )	773	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
736	if (SEQNO_EQ (rcvseq, (*i)->seqno))	774	if (SEQNO_EQ (rcvseq, (*i)->seqno))
737	{	775	{
		776	//printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
738	// enter the packet into our input stream	777	// enter the packet into our input stream
739	r = *i;	778	r = *i;
740		779
741	// remove the oldest packet, look forward, as it's oldest first	780	// remove the oldest packet, look forward, as it's oldest first
742	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)	781	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
743	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))	782	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
744	{	783	{
		784	//printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
745	delete *j;	785	delete *j;
746	rcvpq.erase (j);	786	rcvpq.erase (j);
747	break;	787	break;
748	}	788	}
749		789
750	rcvseq = (rcvseq + 1) & SEQNO_MASK;	790	rcvseq = (rcvseq + 1) & SEQNO_MASK;
751		791
752	if (!rcvdq.put (r->data, r->datalen))	792	if (!rcvdq.put (r->data, r->datalen))
		793	{
		794	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
753	abort (); // MUST never overflow, can be caused by data corruption, TODO	795	abort (); // MUST never overflow, can be caused by data corruption, TODO
		796	}
754		797
755	while (vpn_packet *pkt = rcvdq.get ())	798	while (vpn_packet *pkt = rcvdq.get ())
756	{	799	{
757	sockinfo si;	800	sockinfo si;
758	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	801	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
759		802
760	vpn->recv_vpn_packet (pkt, si);	803	vpn->recv_vpn_packet (pkt, si);
761		804
762	delete pkt;	805	delete pkt;
763	}	806	}
…		…
777	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	820	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
778		821
779	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))	822	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
780	&& pkt.qdcount == htons (1))	823	&& pkt.qdcount == htons (1))
781	{	824	{
782	char qname[MAXSIZE];	825	char qname [MAXSIZE];
783	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);	826	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
784		827
785	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];	828	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
786	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];	829	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
787		830
788	pkt.qdcount = htons (1);	831	pkt.qdcount = htons (1);
789	pkt.ancount = 0;	832	pkt.ancount = 0;
790	pkt.nscount = 0; // should be self, as other nameservers reply like this	833	pkt.nscount = 0; // should be self, as other nameservers reply like this
791	pkt.arcount = 0; // a record for self, as other nameservers reply like this	834	pkt.arcount = 0; // a record for self, as other nameservers reply like this
792		835
793	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	836	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
794		837
795	int dlen = strlen (THISNODE->domain);	838	int dlen = strlen (THISNODE->domain);
796		839
797	if (qclass == RR_CLASS_IN	840	if (qclass == RR_CLASS_IN
798	&& qlen > dlen + 1	841	&& qlen > dlen + 1
799	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	842	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
800	{	843	{
801	// now generate reply	844	// now generate reply
802	pkt.ancount = htons (1); // one answer RR	845	pkt.ancount = htons (1); // one answer RR
803	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	846	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
804		847
…		…
826	if (SEQNO_EQ ((*i)->seqno, seqno))	869	if (SEQNO_EQ ((*i)->seqno, seqno))
827	{	870	{
828	// already seen that request: simply reply with the cached reply	871	// already seen that request: simply reply with the cached reply
829	dns_rcv r = i;	872	dns_rcv r = i;
830		873
831	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	874	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		875
		876	// refresh header & id, as the retry count could have changed
		877	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		878	r->pkt->id = pkt.id;
832		879
833	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);	880	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
834	pkt.id = r->pkt->id;	881
835	goto duplicate_request;	882	goto duplicate_request;
836	}	883	}
837		884
838	// new packet, queue	885	// new packet, queue
839	rcv = new dns_rcv (seqno, data, datalen);	886	rcv = new dns_rcv (seqno, data, datalen);
840	dns->receive_rep (rcv);	887	dns->receive_rep (rcv);
841	}	888	}
842		889
		890	{
843	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section	891	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
844		892
845	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;	893	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
846	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type	894	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
847	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	895	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
848	pkt [offs++] = 0; pkt [offs++] = 0;	896	pkt [offs++] = 0; pkt [offs++] = 0;
849	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL	897	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
850		898
851	int rdlen_offs = offs += 2;	899	int rdlen_offs = offs += 2;
852		900
		901	if (dns)
		902	{
853	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;	903	int dlen = ntohs (dns->cfg.max_size) - offs;
		904
854	// bind doesn't compress well, so reduce further by one label length	905	// bind doesn't compress well, so reduce further by one label length
855	dlen -= qlen;	906	dlen -= qlen;
856		907
857	if (dns)	908	// only put data into in-order sequence packets, if
858	{	909	// we receive out-of-order packets we generate empty
859	while (dlen > 1 && !dns->snddq.empty ())	910	// replies
		911	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		912	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
860	{	913	{
		914	dns->repseq = seqno;
		915
		916	while (dlen > 1 && !dns->snddq.empty ())
		917	{
861	int txtlen = dlen <= 255 ? dlen - 1 : 255;	918	int txtlen = dlen <= 255 ? dlen - 1 : 255;
862		919
863	if (txtlen > dns->snddq.size ())	920	if (txtlen > dns->snddq.size ())
864	txtlen = dns->snddq.size ();	921	txtlen = dns->snddq.size ();
865		922
866	pkt[offs++] = txtlen;	923	pkt[offs++] = txtlen;
867	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);	924	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
868	offs += txtlen;	925	offs += txtlen;
869	dns->snddq.remove (txtlen);	926	dns->snddq.remove (txtlen);
870		927
871	dlen -= txtlen + 1;	928	dlen -= txtlen + 1;
		929	}
872	}	930	}
873		931
874	// avoid empty TXT rdata	932	// avoid completely empty TXT rdata
875	if (offs == rdlen_offs)	933	if (offs == rdlen_offs)
876	pkt[offs++] = 0;	934	pkt[offs++] = 0;
		935
		936	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
877	}	937	}
878	else	938	else
879	{	939	{
880	// send RST	940	// send RST
881	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	941	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
882	pkt [offs++] = CMD_IP_RST;	942	pkt [offs++] = CMD_IP_RST;
883	}	943	}
884		944
885	int rdlen = offs - rdlen_offs;	945	int rdlen = offs - rdlen_offs;
886		946
887	pkt [rdlen_offs - 2] = rdlen >> 8;	947	pkt [rdlen_offs - 2] = rdlen >> 8;
888	pkt [rdlen_offs - 1] = rdlen;	948	pkt [rdlen_offs - 1] = rdlen;
889		949
890	if (dns)	950	if (dns)
891	{	951	{
892	// now update dns_rcv copy	952	// now update dns_rcv copy
893	rcv->pkt->len = offs;	953	rcv->pkt->len = offs;
894	memcpy (rcv->pkt->at (0), pkt.at (0), offs);	954	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
895	}	955	}
		956	}
896		957
897	duplicate_request: ;	958	duplicate_request: ;
898	}	959	}
899	else	960	else
900	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	961	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
…		…
912	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	973	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
913	pkt [offs++] = 0; pkt [offs++] = 0;	974	pkt [offs++] = 0; pkt [offs++] = 0;
914	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL	975	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
915	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength	976	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
916		977
917	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);	978	slog (L_INFO, _("DNS: client %d connects"), client);
918		979
919	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	980	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
920	pkt [offs++] = CMD_IP_REJ;	981	pkt [offs++] = CMD_IP_REJ;
921		982
922	if (0 < client && client <= conns.size ())	983	if (0 < client && client <= conns.size ())
…		…
953	i != dns_sndpq.end ();	1014	i != dns_sndpq.end ();
954	++i)	1015	++i)
955	if ((*i)->pkt->id == pkt.id)	1016	if ((*i)->pkt->id == pkt.id)
956	{	1017	{
957	dns_connection dns = (i)->dns;	1018	dns_connection dns = (i)->dns;
		1019	connection *c = dns->c;
958	int seqno = (*i)->seqno;	1020	int seqno = (*i)->seqno;
959	u8 data[MAXSIZE], *datap = data;	1021	u8 data[MAXSIZE], *datap = data;
		1022	//printf ("rcv pkt %x\n", seqno);//D
960		1023
961	if ((*i)->retry)	1024	if ((*i)->retry)
962	{	1025	{
963	dns->send_interval *= 1.01;	1026	dns->send_interval *= 1.01;
964	if (dns->send_interval < MAX_SEND_INTERVAL)	1027	if (dns->send_interval > MAX_SEND_INTERVAL)
965	dns->send_interval = MAX_SEND_INTERVAL;	1028	dns->send_interval = MAX_SEND_INTERVAL;
966	}	1029	}
967	else	1030	else
968	{	1031	{
		1032	#if 0
969	dns->send_interval *= 0.99;	1033	dns->send_interval *= 0.999;
970	if (dns->send_interval < MIN_SEND_INTERVAL)	1034	#endif
971	dns->send_interval = MIN_SEND_INTERVAL;
972
973	// the latency surely puts an upper bound on	1035	// the latency surely puts an upper bound on
974	// the minimum send interval	1036	// the minimum send interval
975	if (dns->send_interval > NOW - (*i)->sent)	1037	double latency = ev_now () - (*i)->sent;
976	dns->send_interval = NOW - (*i)->sent;	1038
		1039	if (latency < dns->min_latency)
		1040	dns->min_latency = latency;
		1041
		1042	if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
		1043	dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
		1044
		1045	if (dns->send_interval < conf.dns_send_interval)
		1046	dns->send_interval = conf.dns_send_interval;
977	}	1047	}
978		1048
979	delete *i;	1049	delete *i;
980	dns_sndpq.erase (i);	1050	dns_sndpq.erase (i);
981		1051
…		…
1031		1101
1032	if (ip [0] == CMD_IP_1	1102	if (ip [0] == CMD_IP_1
1033	&& ip [1] == CMD_IP_2	1103	&& ip [1] == CMD_IP_2
1034	&& ip [2] == CMD_IP_3)	1104	&& ip [2] == CMD_IP_3)
1035	{	1105	{
1036	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);	1106	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1037		1107
1038	if (ip [3] == CMD_IP_RST)	1108	if (ip [3] == CMD_IP_RST)
1039	{	1109	{
1040	slog (L_DEBUG, _("got tunnel RST request"));	1110	slog (L_DEBUG, _("DNS: got tunnel RST request"));
1041		1111
1042	connection *c = dns->c;
1043	delete c->dns; c->dns = 0;	1112	delete dns; c->dns = 0;
1044		1113
1045	return;	1114	return;
1046	}	1115	}
1047	else if (ip [3] == CMD_IP_SYN)	1116	else if (ip [3] == CMD_IP_SYN)
		1117	{
		1118	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1048	dns->established = true;	1119	dns->established = true;
		1120	}
		1121	else if (ip [3] == CMD_IP_REJ)
		1122	{
		1123	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1124	abort ();
		1125	}
1049	else	1126	else
1050	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);	1127	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1051	}	1128	}
1052	else	1129	else
1053	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),	1130	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1054	ip [0], ip [1], ip [2], ip [3]);	1131	ip [0], ip [1], ip [2], ip [3]);
1055		1132
1056	return;	1133	return;
1057	}	1134	}
1058		1135
1059	int client, rseqno;	1136	int client, rseqno;
1060	decode_header (qname, client, rseqno);	1137	decode_header (qname, client, rseqno);
1061		1138
1062	if (client != THISNODE->id)	1139	if (client != THISNODE->id)
1063	{	1140	{
1064	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));	1141	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1065	datap = 0;	1142	datap = 0;
1066	}	1143	}
1067	else if (rseqno != seqno)	1144	else if (rseqno != seqno)
1068	{	1145	{
1069	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));	1146	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
1070	datap = 0;	1147	datap = 0;
1071	}	1148	}
1072	}	1149	}
1073	}	1150	}
1074		1151
…		…
1079	break;	1156	break;
1080	}	1157	}
1081	}	1158	}
1082		1159
1083	void	1160	void
1084	vpn::dnsv4_ev (io_watcher &w, short revents)	1161	vpn::dnsv4_ev (ev::io &w, int revents)
1085	{	1162	{
1086	if (revents & EVENT_READ)	1163	if (revents & EV_READ)
1087	{	1164	{
1088	dns_packet *pkt = new dns_packet;	1165	dns_packet *pkt = new dns_packet;
1089	struct sockaddr_in sa;	1166	struct sockaddr_in sa;
1090	socklen_t sa_len = sizeof (sa);	1167	socklen_t sa_len = sizeof (sa);
1091		1168
1092	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);	1169	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1093		1170
1094	if (pkt->len > 0)	1171	if (pkt->len > 0)
1095	{	1172	{
1096	if (THISNODE->dns_port)	1173	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1174	dnsv4_client (*pkt);
		1175	else
1097	{	1176	{
1098	dnsv4_server (*pkt);	1177	dnsv4_server (*pkt);
1099	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);	1178	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1100	}	1179	}
1101	else
1102	dnsv4_client (*pkt);
1103		1180
1104	delete pkt;	1181	delete pkt;
1105	}	1182	}
1106	}	1183	}
1107	}	1184	}
1108		1185
1109	bool	1186	bool
1110	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1187	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1111	{	1188	{
		1189	int client = ntohl (si.host);
		1190
		1191	assert (0 < client && client <= conns.size ());
		1192
		1193	connection *c = conns [client - 1];
		1194
1112	if (!dns)	1195	if (!c->dns)
1113	dns = new dns_connection (this);	1196	c->dns = new dns_connection (c);
1114		1197
1115	if (!dns->snddq.put (pkt))	1198	if (c->dns->snddq.put (pkt))
1116	return false;	1199	c->dns->tw ();
1117		1200
1118	dns->tw.trigger ();	1201	// always return true even if the buffer overflows
1119
1120	return true;	1202	return true;
1121	}	1203	}
1122		1204
		1205	void
		1206	connection::dnsv4_reset_connection ()
		1207	{
		1208	//delete dns; dns = 0; //TODO
		1209	}
		1210
1123	#define NEXT(w) do { if (next > (w)) next = w; } while (0)	1211	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1124		1212
1125	void	1213	void
1126	dns_connection::time_cb (time_watcher &w)	1214	dns_connection::time_cb (ev::timer &w, int revents)
1127	{	1215	{
1128	// servers have to be polled	1216	// servers have to be polled
1129	if (THISNODE->dns_port)	1217	if (THISNODE->dns_port)
1130	return;	1218	return;
1131		1219
1132	// check for timeouts and (re)transmit	1220	// check for timeouts and (re)transmit
1133	tstamp next = NOW + poll_interval;	1221	tstamp next = ev::now () + poll_interval;
1134	dns_snd *send = 0;	1222	dns_snd *send = 0;
1135		1223
1136	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();	1224	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1137	i != vpn->dns_sndpq.end ();	1225	i != vpn->dns_sndpq.end ();
1138	++i)	1226	++i)
1139	{	1227	{
1140	dns_snd r = i;	1228	dns_snd r = i;
1141		1229
1142	if (r->timeout <= NOW)	1230	if (r->timeout <= ev_now ())
1143	{	1231	{
1144	if (!send)	1232	if (!send)
1145	{	1233	{
1146	send = r;	1234	send = r;
1147		1235
1148	r->retry++;	1236	r->retry++;
1149	r->timeout = NOW + r->retry;	1237	r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
		1238	//printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
		1239
		1240	// the following code changes the query section a bit, forcing
		1241	// the forwarder to generate a new request
		1242	if (r->stdhdr)
		1243	encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
1150	}	1244	}
1151	}	1245	}
1152	else	1246	else
1153	NEXT (r->timeout);	1247	NEXT (r->timeout);
1154	}	1248	}
1155		1249
1156	if (last_sent + send_interval <= NOW)
1157	{
1158	if (!send)	1250	if (!send)
		1251	{
		1252	// generate a new packet, if wise
		1253
		1254	if (!established)
1159	{	1255	{
1160	// generate a new packet, if wise
1161
1162	if (!established)
1163	{
1164	if (vpn->dns_sndpq.empty ())	1256	if (vpn->dns_sndpq.empty ())
1165	{
1166	send = new dns_snd (this);
1167
1168	cfg.reset (THISNODE->id);
1169	send->gen_syn_req (cfg);
1170	}
1171	}
1172	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
1173	{	1257	{
1174	send = new dns_snd (this);	1258	send = new dns_snd (this);
		1259
		1260	cfg.reset (THISNODE->id);
		1261	send->gen_syn_req ();
		1262	}
		1263	}
		1264	else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
		1265	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1266	{
		1267	if (last_sent + send_interval <= ev_now ())
		1268	{
		1269	//printf ("sending data request etc.\n"); //D
		1270	if (!snddq.empty () \|\| last_received + 1. > ev_now ())
		1271	{
		1272	poll_interval = send_interval;
		1273	NEXT (ev_now () + send_interval);
		1274	}
		1275
		1276	send = new dns_snd (this);
1175	send->gen_stream_req (sndseq, snddq);	1277	send->gen_stream_req (sndseq, snddq);
		1278	send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
		1279	//printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
1176		1280
1177	sndseq = (sndseq + 1) & SEQNO_MASK;	1281	sndseq = (sndseq + 1) & SEQNO_MASK;
1178	}	1282	}
1179		1283	else
1180	if (send)	1284	NEXT (last_sent + send_interval);
1181	vpn->dns_sndpq.push_back (send);
1182	}	1285	}
1183		1286
1184	if (send)	1287	if (send)
1185	{	1288	vpn->dns_sndpq.push_back (send);
1186	last_sent = NOW;	1289	}
1187		1290
		1291	if (send)
		1292	{
		1293	last_sent = ev_now ();
1188	sendto (vpn->dnsv4_fd,	1294	sendto (vpn->dnsv4_fd,
1189	send->pkt->at (0), send->pkt->len, 0,	1295	send->pkt->at (0), send->pkt->len, 0,
1190	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1296	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1191	}
1192	}	1297	}
1193	else
1194	NEXT (last_sent + send_interval);
1195		1298
1196	//printf ("pi %f si %f N %f (%d:%d)\n", poll_interval, send_interval, next - NOW, vpn->dns_sndpq.size (), snddq.size ());	1299	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1300	poll_interval, send_interval, next - ev_now (),
		1301	vpn->dns_sndpq.size (), snddq.size (),
		1302	rcvpq.size ());
1197		1303
1198	// TODO: no idea when this happens, but when next < NOW, we have a problem	1304	// TODO: no idea when this happens, but when next < ev_now (), we have a problem
		1305	// doesn't seem to happen anymore
1199	if (next < NOW + 0.0001)	1306	if (next < ev_now () + 0.001)
1200	next = NOW + 0.1;	1307	next = ev_now () + 0.1;
1201		1308
1202	w.start (next);	1309	w.start (next - ev_now ());
1203	}	1310	}
1204		1311
1205	#endif	1312	#endif
1206		1313

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.11 by pcg, Fri Mar 4 08:45:24 2005 UTC vs. Revision 1.43 by pcg, Sat Dec 1 23:35:31 2007 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.11 by pcg, Fri Mar 4 08:45:24 2005 UTC vs.
Revision 1.43 by pcg, Sat Dec 1 23:35:31 2007 UTC