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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC vs.
Revision 1.39 by pcg, Tue Apr 26 00:55:56 2005 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 .02 // how often to poll minimally when the server has 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. // retry timeouts	56	#define INITIAL_TIMEOUT 0.1 // retry timeouts
53	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn	57	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54		58
55	#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
56	#define MAX_SEND_INTERVAL 0.5 // optimistic?	59	#define MAX_SEND_INTERVAL 2. // optimistic?
57		60
58	#define MAX_OUTSTANDING 40 // max. outstanding requests
59	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING	61	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
60	#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), 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 bytes less 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	unsigned 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	{
439	return id1 == 'G'	466	return id1 == 'G'
440	&& id2 == 'V'	467	&& id2 == 'V'
441	&& id3 == 'P'	468	&& id3 == 'P'
442	&& id4 == 'E'	469	&& id4 == 'E'
		470	&& seq_cdc == 26
		471	&& req_cdc == 62
		472	&& rep_cdc == 0
443	&& version == 1	473	&& version == 1;
444	&& flags == 0
445	&& rcv_cdc == 0
446	&& snd_cdc == 62
447	&& max_size == ntohs (MAX_PKT_SIZE);
448	}	474	}
449		475
450	struct dns_packet : net_packet	476	struct dns_packet : net_packet
451	{	477	{
452	u16 id;	478	u16 id;
453	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
454	u16 qdcount, ancount, nscount, arcount;	480	u16 qdcount, ancount, nscount, arcount;
455		481
456	u8 data[MAXSIZE - 6 * 2];	482	u8 data [MAXSIZE - 6 * 2];
457		483
458	int decode_label (char *data, int size, int &offs);	484	int decode_label (char *data, int size, int &offs);
459	};	485	};
460		486
461	int dns_packet::decode_label (char *data, int size, int &offs)	487	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
492	return data - orig;	518	return data - orig;
493	}	519	}
494		520
495	/////////////////////////////////////////////////////////////////////////////	521	/////////////////////////////////////////////////////////////////////////////
496		522
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	523	static u16 dns_id = 0; // TODO: should be per-vpn
513		524
514	static u16 next_id ()	525	static u16 next_id ()
515	{	526	{
		527	if (!dns_id)
		528	dns_id = time (0);
		529
516	// the simplest lsfr with periodicity 65535 i could find	530	// the simplest lsfr with periodicity 65535 i could find
517	dns_id = (dns_id << 1)	531	dns_id = (dns_id << 1)
518	\| (((dns_id >> 1)	532	\| (((dns_id >> 1)
519	^ (dns_id >> 2)	533	^ (dns_id >> 2)
520	^ (dns_id >> 4)	534	^ (dns_id >> 4)
521	^ (dns_id >> 15)) & 1);	535	^ (dns_id >> 15)) & 1);
522		536
523	return dns_id;	537	return dns_id;
524	}	538	}
525		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
526	dns_snd::dns_snd (dns_connection *dns)	585	dns_snd::dns_snd (dns_connection *dns)
527	: dns (dns)	586	: dns (dns)
528	{	587	{
529	timeout = 0;	588	timeout = 0;
530	retry = 0;	589	retry = 0;
531	seqno = 0;	590	seqno = 0;
532	sent = NOW;	591	sent = NOW;
		592	stdhdr = false;
533		593
534	pkt = new dns_packet;	594	pkt = new dns_packet;
535		595
536	pkt->id = next_id ();	596	pkt->id = next_id ();
537	}	597	}
…		…
564	}	624	}
565	}	625	}
566		626
567	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)	627	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
568	{	628	{
		629	stdhdr = true;
569	this->seqno = seqno;	630	this->seqno = seqno;
570		631
571	timeout = NOW + INITIAL_TIMEOUT;	632	timeout = NOW + INITIAL_TIMEOUT;
572		633
573	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	634	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
574	pkt->qdcount = htons (1);	635	pkt->qdcount = htons (1);
575		636
576	int offs = 6*2;	637	int offs = 6*2;
577	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	638	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,	639	// 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	640	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
580		641
581	char enc[256], *encp = enc;	642	char enc[256], *encp = enc;
582	encode_header (enc, THISNODE->id, seqno);	643	encode_header (enc, THISNODE->id, seqno);
…		…
600	encp += lbllen;	661	encp += lbllen;
601		662
602	enclen -= lbllen;	663	enclen -= lbllen;
603	}	664	}
604		665
605	append_domain (*pkt, offs, THISNODE->domain);	666	append_domain (*pkt, offs, dns->c->conf->domain);
606		667
607	(*pkt)[offs++] = 0;	668	(*pkt)[offs++] = 0;
608	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	669	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
609	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	670	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
610		671
611	pkt->len = offs;	672	pkt->len = offs;
612	}	673	}
613		674
614	void dns_snd::gen_syn_req (const dns_cfg &cfg)	675	void dns_snd::gen_syn_req ()
615	{	676	{
616	timeout = NOW + INITIAL_SYN_TIMEOUT;	677	timeout = NOW + INITIAL_SYN_TIMEOUT;
617		678
618	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	679	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
619	pkt->qdcount = htons (1);	680	pkt->qdcount = htons (1);
620		681
621	int offs = 6*2;	682	int offs = 6 * 2;
622		683
623	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));
624		685
625	assert (elen <= MAX_LBL_SIZE);	686	assert (elen <= MAX_LBL_SIZE);
626		687
627	(*pkt)[offs] = elen;	688	(*pkt)[offs] = elen;
628	offs += elen + 1;	689	offs += elen + 1;
629	append_domain (*pkt, offs, THISNODE->domain);	690	append_domain (*pkt, offs, dns->c->conf->domain);
630		691
631	(*pkt)[offs++] = 0;	692	(*pkt)[offs++] = 0;
632	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;	693	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
633	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	694	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
634		695
…		…
657	delete pkt;	718	delete pkt;
658	}	719	}
659		720
660	/////////////////////////////////////////////////////////////////////////////	721	/////////////////////////////////////////////////////////////////////////////
661		722
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)	723	dns_connection::dns_connection (connection *c)
688	: c (c)	724	: c (c)
689	, rcvdq (MAX_BACKLOG * 2)	725	, rcvdq (MAX_BACKLOG * 2)
690	, snddq (MAX_BACKLOG * 2)	726	, snddq (MAX_BACKLOG)
691	, tw (this, &dns_connection::time_cb)	727	, tw (this, &dns_connection::time_cb)
692	{	728	{
693	vpn = c->vpn;	729	vpn = c->vpn;
694		730
695	established = false;	731	established = false;
696		732
697	rcvseq = sndseq = 0;	733	rcvseq = repseq = sndseq = 0;
698		734
699	last_sent = last_received = 0;	735	last_sent = last_received = 0;
700	poll_interval = MIN_POLL_INTERVAL;	736	poll_interval = 0.5; // starting here
701	send_interval = 0.2; // starting rate	737	send_interval = 0.5; // starting rate
		738	min_latency = INITIAL_TIMEOUT;
702	}	739	}
703		740
704	dns_connection::~dns_connection ()	741	dns_connection::~dns_connection ()
705	{	742	{
706	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	743	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
…		…
718		755
719	poll_interval = send_interval;	756	poll_interval = send_interval;
720	}	757	}
721	else	758	else
722	{	759	{
723	poll_interval *= 1.1;	760	poll_interval *= 1.5;
		761
724	if (poll_interval > MAX_POLL_INTERVAL)	762	if (poll_interval > MAX_POLL_INTERVAL)
725	poll_interval = MAX_POLL_INTERVAL;	763	poll_interval = MAX_POLL_INTERVAL;
726	}	764	}
727		765
728	rcvpq.push_back (r);	766	rcvpq.push_back (r);
…		…
746	}	784	}
747		785
748	rcvseq = (rcvseq + 1) & SEQNO_MASK;	786	rcvseq = (rcvseq + 1) & SEQNO_MASK;
749		787
750	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)");
751	abort (); // MUST never overflow, can be caused by data corruption, TODO	791	abort (); // MUST never overflow, can be caused by data corruption, TODO
		792	}
752		793
753	while (vpn_packet *pkt = rcvdq.get ())	794	while (vpn_packet *pkt = rcvdq.get ())
754	{	795	{
755	sockinfo si;	796	sockinfo si;
756	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	797	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
757		798
758	vpn->recv_vpn_packet (pkt, si);	799	vpn->recv_vpn_packet (pkt, si);
759		800
760	delete pkt;	801	delete pkt;
761	}	802	}
…		…
775	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	816	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
776		817
777	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))	818	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
778	&& pkt.qdcount == htons (1))	819	&& pkt.qdcount == htons (1))
779	{	820	{
780	char qname[MAXSIZE];	821	char qname [MAXSIZE];
781	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);	822	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
782		823
783	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];	824	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
784	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];	825	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
785		826
786	pkt.qdcount = htons (1);	827	pkt.qdcount = htons (1);
787	pkt.ancount = 0;	828	pkt.ancount = 0;
788	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
789	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
790		831
791	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	832	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
792		833
793	int dlen = strlen (THISNODE->domain);	834	int dlen = strlen (THISNODE->domain);
794		835
795	if (qclass == RR_CLASS_IN	836	if (qclass == RR_CLASS_IN
796	&& qlen > dlen + 1	837	&& qlen > dlen + 1
797	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	838	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
798	{	839	{
799	// now generate reply	840	// now generate reply
800	pkt.ancount = htons (1); // one answer RR	841	pkt.ancount = htons (1); // one answer RR
801	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	842	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
802		843
…		…
824	if (SEQNO_EQ ((*i)->seqno, seqno))	865	if (SEQNO_EQ ((*i)->seqno, seqno))
825	{	866	{
826	// already seen that request: simply reply with the cached reply	867	// already seen that request: simply reply with the cached reply
827	dns_rcv r = i;	868	dns_rcv r = i;
828		869
829	slog (L_DEBUG, "DUPLICATE %d\n", htons (r->pkt->id));	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;
830		875
831	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);
832	pkt.id = r->pkt->id;	877
833	goto duplicate_request;	878	goto duplicate_request;
834	}	879	}
835		880
836	// new packet, queue	881	// new packet, queue
837	rcv = new dns_rcv (seqno, data, datalen);	882	rcv = new dns_rcv (seqno, data, datalen);
838	dns->receive_rep (rcv);	883	dns->receive_rep (rcv);
839	}	884	}
840		885
		886	{
841	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
842		888
843	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;	889	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
844	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type	890	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
845	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	891	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
846	pkt [offs++] = 0; pkt [offs++] = 0;	892	pkt [offs++] = 0; pkt [offs++] = 0;
847	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL	893	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
848		894
849	int rdlen_offs = offs += 2;	895	int rdlen_offs = offs += 2;
850		896
		897	if (dns)
		898	{
851	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;	899	int dlen = ntohs (dns->cfg.max_size) - offs;
		900
852	// 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
853	dlen -= qlen;	902	dlen -= qlen;
854		903
855	if (dns)	904	// only put data into in-order sequence packets, if
856	{	905	// we receive out-of-order packets we generate empty
857	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)
858	{	909	{
		910	dns->repseq = seqno;
		911
		912	while (dlen > 1 && !dns->snddq.empty ())
		913	{
859	int txtlen = dlen <= 255 ? dlen - 1 : 255;	914	int txtlen = dlen <= 255 ? dlen - 1 : 255;
860		915
861	if (txtlen > dns->snddq.size ())	916	if (txtlen > dns->snddq.size ())
862	txtlen = dns->snddq.size ();	917	txtlen = dns->snddq.size ();
863		918
864	pkt[offs++] = txtlen;	919	pkt[offs++] = txtlen;
865	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);	920	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
866	offs += txtlen;	921	offs += txtlen;
867	dns->snddq.remove (txtlen);	922	dns->snddq.remove (txtlen);
868		923
869	dlen -= txtlen + 1;	924	dlen -= txtlen + 1;
		925	}
870	}	926	}
871		927
872	// avoid empty TXT rdata	928	// avoid completely empty TXT rdata
873	if (offs == rdlen_offs)	929	if (offs == rdlen_offs)
874	pkt[offs++] = 0;	930	pkt[offs++] = 0;
875		931
876	slog (L_NOISE, "snddq %d", dns->snddq.size ());	932	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
877	}	933	}
878	else	934	else
879	{	935	{
880	// send RST	936	// send RST
881	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;
882	pkt [offs++] = CMD_IP_RST;	938	pkt [offs++] = CMD_IP_RST;
883	}	939	}
884		940
885	int rdlen = offs - rdlen_offs;	941	int rdlen = offs - rdlen_offs;
886		942
887	pkt [rdlen_offs - 2] = rdlen >> 8;	943	pkt [rdlen_offs - 2] = rdlen >> 8;
888	pkt [rdlen_offs - 1] = rdlen;	944	pkt [rdlen_offs - 1] = rdlen;
889		945
890	if (dns)	946	if (dns)
891	{	947	{
892	// now update dns_rcv copy	948	// now update dns_rcv copy
893	rcv->pkt->len = offs;	949	rcv->pkt->len = offs;
894	memcpy (rcv->pkt->at (0), pkt.at (0), offs);	950	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
895	}	951	}
		952	}
896		953
897	duplicate_request: ;	954	duplicate_request: ;
898	}	955	}
899	else	956	else
900	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	957	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
…		…
912	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
913	pkt [offs++] = 0; pkt [offs++] = 0;	970	pkt [offs++] = 0; pkt [offs++] = 0;
914	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL	971	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
915	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength	972	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
916		973
917	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);	974	slog (L_INFO, _("DNS: client %d connects"), client);
918		975
919	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;
920	pkt [offs++] = CMD_IP_REJ;	977	pkt [offs++] = CMD_IP_REJ;
921		978
922	if (0 < client && client <= conns.size ())	979	if (0 < client && client <= conns.size ())
…		…
959	int seqno = (*i)->seqno;	1016	int seqno = (*i)->seqno;
960	u8 data[MAXSIZE], *datap = data;	1017	u8 data[MAXSIZE], *datap = data;
961		1018
962	if ((*i)->retry)	1019	if ((*i)->retry)
963	{	1020	{
964	dns->send_interval *= 1.001;	1021	dns->send_interval *= 1.01;
965	if (dns->send_interval > MAX_SEND_INTERVAL)	1022	if (dns->send_interval > MAX_SEND_INTERVAL)
966	dns->send_interval = MAX_SEND_INTERVAL;	1023	dns->send_interval = MAX_SEND_INTERVAL;
967	}	1024	}
968	else	1025	else
969	{	1026	{
970	#if 1	1027	#if 0
971	dns->send_interval *= 0.9999;	1028	dns->send_interval *= 0.999;
972	#endif	1029	#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	1030	// the latency surely puts an upper bound on
977	// the minimum send interval	1031	// the minimum send interval
978	double latency = NOW - (*i)->sent;	1032	double latency = NOW - (*i)->sent;
979		1033
980	if (dns->send_interval > latency)	1034	if (latency < dns->min_latency)
981	dns->send_interval = 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;
982	}	1042	}
983		1043
984	delete *i;	1044	delete *i;
985	dns_sndpq.erase (i);	1045	dns_sndpq.erase (i);
986		1046
…		…
1036		1096
1037	if (ip [0] == CMD_IP_1	1097	if (ip [0] == CMD_IP_1
1038	&& ip [1] == CMD_IP_2	1098	&& ip [1] == CMD_IP_2
1039	&& ip [2] == CMD_IP_3)	1099	&& ip [2] == CMD_IP_3)
1040	{	1100	{
1041	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);	1101	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1042		1102
1043	if (ip [3] == CMD_IP_RST)	1103	if (ip [3] == CMD_IP_RST)
1044	{	1104	{
1045	slog (L_DEBUG, _("got tunnel RST request"));	1105	slog (L_DEBUG, _("DNS: got tunnel RST request"));
1046		1106
1047	delete dns; c->dns = 0;	1107	delete dns; c->dns = 0;
1048		1108
1049	return;	1109	return;
1050	}	1110	}
1051	else if (ip [3] == CMD_IP_SYN)	1111	else if (ip [3] == CMD_IP_SYN)
1052	{	1112	{
1053	slog (L_DEBUG, _("got tunnel SYN reply, server likes us."));	1113	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1054	dns->established = true;	1114	dns->established = true;
1055	}	1115	}
1056	else if (ip [3] == CMD_IP_REJ)	1116	else if (ip [3] == CMD_IP_REJ)
1057	{	1117	{
1058	slog (L_DEBUG, _("got tunnel REJ reply, server does not like us, aborting."));	1118	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
1059	abort ();	1119	abort ();
1060	}	1120	}
1061	else	1121	else
1062	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);	1122	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1063	}	1123	}
1064	else	1124	else
1065	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),	1125	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1066	ip [0], ip [1], ip [2], ip [3]);	1126	ip [0], ip [1], ip [2], ip [3]);
1067		1127
1068	return;	1128	return;
1069	}	1129	}
1070		1130
1071	int client, rseqno;	1131	int client, rseqno;
1072	decode_header (qname, client, rseqno);	1132	decode_header (qname, client, rseqno);
1073		1133
1074	if (client != THISNODE->id)	1134	if (client != THISNODE->id)
1075	{	1135	{
1076	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));	1136	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1077	datap = 0;	1137	datap = 0;
1078	}	1138	}
1079	else if (rseqno != seqno)	1139	else if (rseqno != seqno)
1080	{	1140	{
1081	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?"));
1082	datap = 0;	1142	datap = 0;
1083	}	1143	}
1084	}	1144	}
1085	}	1145	}
1086		1146
…		…
1103		1163
1104	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);
1105		1165
1106	if (pkt->len > 0)	1166	if (pkt->len > 0)
1107	{	1167	{
1108	if (THISNODE->dns_port)	1168	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1169	dnsv4_client (*pkt);
		1170	else
1109	{	1171	{
1110	dnsv4_server (*pkt);	1172	dnsv4_server (*pkt);
1111	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);
1112	}	1174	}
1113	else
1114	dnsv4_client (*pkt);
1115		1175
1116	delete pkt;	1176	delete pkt;
1117	}	1177	}
1118	}	1178	}
1119	}	1179	}
1120		1180
1121	bool	1181	bool
1122	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)
1123	{	1183	{
		1184	int client = ntohl (si.host);
		1185
		1186	assert (0 < client && client <= conns.size ());
		1187
		1188	connection *c = conns [client - 1];
		1189
1124	if (!dns)	1190	if (!c->dns)
1125	dns = new dns_connection (this);	1191	c->dns = new dns_connection (c);
1126		1192
1127	if (!dns->snddq.put (pkt))	1193	if (c->dns->snddq.put (pkt))
1128	return false;
1129
1130	dns->tw.trigger ();	1194	c->dns->tw.trigger ();
1131		1195
		1196	// always return true even if the buffer overflows
1132	return true;	1197	return true;
1133	}	1198	}
1134		1199
1135	void	1200	void
1136	connection::dnsv4_reset_connection ()	1201	connection::dnsv4_reset_connection ()
…		…
1162	if (!send)	1227	if (!send)
1163	{	1228	{
1164	send = r;	1229	send = r;
1165		1230
1166	r->retry++;	1231	r->retry++;
1167	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	}
1168	}	1241	}
1169	}	1242	}
1170	else	1243	else
1171	NEXT (r->timeout);	1244	NEXT (r->timeout);
1172	}	1245	}
1173		1246
1174	if (last_sent + send_interval <= NOW)
1175	{
1176	if (!send)	1247	if (!send)
		1248	{
		1249	// generate a new packet, if wise
		1250
		1251	if (!established)
1177	{	1252	{
1178	// generate a new packet, if wise
1179
1180	if (!established)
1181	{
1182	if (vpn->dns_sndpq.empty ())	1253	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	}
1190	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
1191	{	1254	{
1192	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);
1193	send->gen_stream_req (sndseq, snddq);	1274	send->gen_stream_req (sndseq, snddq);
		1275	send->timeout = NOW + min_latency * conf.dns_timeout_factor;
1194		1276
1195	sndseq = (sndseq + 1) & SEQNO_MASK;	1277	sndseq = (sndseq + 1) & SEQNO_MASK;
1196	}	1278	}
1197		1279	else
1198	if (send)	1280	NEXT (last_sent + send_interval);
1199	vpn->dns_sndpq.push_back (send);
1200	}	1281	}
1201		1282
1202	if (send)	1283	if (send)
1203	{	1284	vpn->dns_sndpq.push_back (send);
		1285	}
		1286
		1287	if (send)
		1288	{
1204	last_sent = NOW;	1289	last_sent = NOW;
1205	sendto (vpn->dnsv4_fd,	1290	sendto (vpn->dnsv4_fd,
1206	send->pkt->at (0), send->pkt->len, 0,	1291	send->pkt->at (0), send->pkt->len, 0,
1207	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1292	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1208	}
1209	}	1293	}
1210	else
1211	NEXT (last_sent + send_interval);
1212		1294
1213	slog (L_NOISE, "pi %f si %f N %f (%d:%d)",	1295	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1214	poll_interval, send_interval, next - NOW,	1296	poll_interval, send_interval, next - NOW,
1215	vpn->dns_sndpq.size (), snddq.size ());	1297	vpn->dns_sndpq.size (), snddq.size (),
		1298	rcvpq.size ());
1216		1299
1217	// TODO: no idea when this happens, but when next < NOW, we have a problem	1300	// TODO: no idea when this happens, but when next < NOW, we have a problem
		1301	// doesn't seem to happen anymore
1218	if (next < NOW + 0.0001)	1302	if (next < NOW + 0.001)
1219	next = NOW + 0.1;	1303	next = NOW + 0.1;
1220		1304
1221	w.start (next);	1305	w.start (next);
1222	}	1306	}
1223		1307

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC vs. Revision 1.39 by pcg, Tue Apr 26 00:55:56 2005 UTC

Diff Legend

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC vs.
Revision 1.39 by pcg, Tue Apr 26 00:55:56 2005 UTC