[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 1.27 by pcg, Sat Mar 12 18:10:40 2005 UTC

…		…
25		25
26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.	26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27	// it's a hack, use only in emergency situations please.	27	// it's a hack, use only in emergency situations please.
28		28
29	#include <cstring>	29	#include <cstring>
		30	#include <cassert>
30		31
31	#include <sys/types.h>	32	#include <sys/types.h>
32	#include <sys/socket.h>	33	#include <sys/socket.h>
33	#include <sys/wait.h>	34	#include <sys/wait.h>
34	#include <sys/uio.h>	35	#include <sys/uio.h>
…		…
43		44
44	#include "netcompat.h"	45	#include "netcompat.h"
45		46
46	#include "vpn.h"	47	#include "vpn.h"
47		48
48	#define MIN_POLL_INTERVAL .2 // how often to poll minimally when the server is having data	49	#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	50	#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data
50	#define ACTIVITY_INTERVAL 5.	51	#define ACTIVITY_INTERVAL 5.
51		52
52	#define INITIAL_TIMEOUT 1.	53	#define INITIAL_TIMEOUT 0.1 // retry timeouts
53	#define INITIAL_SYN_TIMEOUT 2.	54	#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn
54		55
55	#define MIN_SEND_INTERVAL 0.001	56	#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
56	#define MAX_SEND_INTERVAL 0.5 // optimistic?	57	#define MAX_SEND_INTERVAL 2. // optimistic?
57		58
		59	#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
58	#define MAX_OUTSTANDING 400 // max. outstanding requests	60	#define MAX_OUTSTANDING 40 // 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 (100*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 200 // 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 two request bytes less give room for one reply byte
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 r2, r3, r4;
		430
		431	u8 r5, r6, r7, r8;
409		432
410	void reset (int clientid);	433	void reset (int clientid);
411	bool valid ();	434	bool valid ();
412	};	435	};
413		436
…		…
423	version = 1;	446	version = 1;
424		447
425	rrtype = RR_TYPE_TXT;	448	rrtype = RR_TYPE_TXT;
426	flags = 0;	449	flags = 0;
427	def_ttl = 0;	450	def_ttl = 0;
		451	seq_cdc = 26;
		452	req_cdc = 62;
428	rcv_cdc = 0;	453	rep_cdc = 0;
429	snd_cdc = 62;
430	max_size = ntohs (MAX_PKT_SIZE);	454	max_size = htons (MAX_PKT_SIZE);
431	client = ntohs (clientid);	455	client = htons (clientid);
432	uid = next_uid++;	456	uid = next_uid++;
433		457
434	memset (reserved, 0, 8);	458	r2 = r3 = r4 = 0;
		459	r4 = r5 = r6 = r7 = 0;
435	}	460	}
436		461
437	bool dns_cfg::valid ()	462	bool dns_cfg::valid ()
438	{	463	{
439	return id1 == 'G'	464	return id1 == 'G'
440	&& id2 == 'V'	465	&& id2 == 'V'
441	&& id3 == 'P'	466	&& id3 == 'P'
442	&& id4 == 'E'	467	&& id4 == 'E'
		468	&& seq_cdc == 26
		469	&& req_cdc == 62
		470	&& rep_cdc == 0
443	&& version == 1	471	&& version == 1;
444	&& flags == 0
445	&& rcv_cdc == 0
446	&& snd_cdc == 62
447	&& max_size == ntohs (MAX_PKT_SIZE);
448	}	472	}
449		473
450	struct dns_packet : net_packet	474	struct dns_packet : net_packet
451	{	475	{
452	u16 id;	476	u16 id;
453	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	477	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
454	u16 qdcount, ancount, nscount, arcount;	478	u16 qdcount, ancount, nscount, arcount;
455		479
456	u8 data[MAXSIZE - 6 * 2];	480	u8 data [MAXSIZE - 6 * 2];
457		481
458	int decode_label (char *data, int size, int &offs);	482	int decode_label (char *data, int size, int &offs);
459	};	483	};
460		484
461	int dns_packet::decode_label (char *data, int size, int &offs)	485	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
492	return data - orig;	516	return data - orig;
493	}	517	}
494		518
495	/////////////////////////////////////////////////////////////////////////////	519	/////////////////////////////////////////////////////////////////////////////
496		520
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	521	static u16 dns_id = 0; // TODO: should be per-vpn
513		522
514	static u16 next_id ()	523	static u16 next_id ()
515	{	524	{
		525	if (!dns_id)
		526	dns_id = time (0);
		527
516	// the simplest lsfr with periodicity 65535 i could find	528	// the simplest lsfr with periodicity 65535 i could find
517	dns_id = (dns_id << 1)	529	dns_id = (dns_id << 1)
518	\| (((dns_id >> 1)	530	\| (((dns_id >> 1)
519	^ (dns_id >> 2)	531	^ (dns_id >> 2)
520	^ (dns_id >> 4)	532	^ (dns_id >> 4)
521	^ (dns_id >> 15)) & 1);	533	^ (dns_id >> 15)) & 1);
522		534
523	return dns_id;	535	return dns_id;
524	}	536	}
525		537
		538	struct dns_rcv;
		539	struct dns_snd;
		540
		541	struct dns_connection
		542	{
		543	connection *c;
		544	struct vpn *vpn;
		545
		546	dns_cfg cfg;
		547
		548	bool established;
		549
		550	tstamp last_received;
		551	tstamp last_sent;
		552	double min_latency;
		553	double poll_interval, send_interval;
		554
		555	vector<dns_rcv *> rcvpq;
		556
		557	byte_stream rcvdq; int rcvseq;
		558	byte_stream snddq; int sndseq;
		559
		560	void time_cb (time_watcher &w); time_watcher tw;
		561	void receive_rep (dns_rcv *r);
		562
		563	dns_connection (connection *c);
		564	~dns_connection ();
		565	};
		566
		567	struct dns_snd
		568	{
		569	dns_packet *pkt;
		570	tstamp timeout, sent;
		571	int retry;
		572	struct dns_connection *dns;
		573	int seqno;
		574	bool stdhdr;
		575
		576	void gen_stream_req (int seqno, byte_stream &stream);
		577	void gen_syn_req ();
		578
		579	dns_snd (dns_connection *dns);
		580	~dns_snd ();
		581	};
		582
526	dns_snd::dns_snd (dns_connection *dns)	583	dns_snd::dns_snd (dns_connection *dns)
527	: dns (dns)	584	: dns (dns)
528	{	585	{
529	timeout = 0;	586	timeout = 0;
530	retry = 0;	587	retry = 0;
531	seqno = 0;	588	seqno = 0;
532	sent = NOW;	589	sent = NOW;
		590	stdhdr = false;
533		591
534	pkt = new dns_packet;	592	pkt = new dns_packet;
535		593
536	pkt->id = next_id ();	594	pkt->id = next_id ();
537	}	595	}
…		…
564	}	622	}
565	}	623	}
566		624
567	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)	625	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
568	{	626	{
		627	stdhdr = true;
569	this->seqno = seqno;	628	this->seqno = seqno;
570		629
571	timeout = NOW + INITIAL_TIMEOUT;	630	timeout = NOW + INITIAL_TIMEOUT;
572		631
573	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	632	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
574	pkt->qdcount = htons (1);	633	pkt->qdcount = htons (1);
575		634
576	int offs = 6*2;	635	int offs = 6*2;
577	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	636	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,	637	// 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	638	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
580		639
581	char enc[256], *encp = enc;	640	char enc[256], *encp = enc;
582	encode_header (enc, THISNODE->id, seqno);	641	encode_header (enc, THISNODE->id, seqno);
…		…
600	encp += lbllen;	659	encp += lbllen;
601		660
602	enclen -= lbllen;	661	enclen -= lbllen;
603	}	662	}
604		663
605	append_domain (*pkt, offs, THISNODE->domain);	664	append_domain (*pkt, offs, dns->c->conf->domain);
606		665
607	(*pkt)[offs++] = 0;	666	(*pkt)[offs++] = 0;
608	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	667	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
609	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	668	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
610		669
611	pkt->len = offs;	670	pkt->len = offs;
612	}	671	}
613		672
614	void dns_snd::gen_syn_req (const dns_cfg &cfg)	673	void dns_snd::gen_syn_req ()
615	{	674	{
616	timeout = NOW + INITIAL_SYN_TIMEOUT;	675	timeout = NOW + INITIAL_SYN_TIMEOUT;
617		676
618	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	677	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
619	pkt->qdcount = htons (1);	678	pkt->qdcount = htons (1);
620		679
621	int offs = 6*2;	680	int offs = 6 * 2;
622		681
623	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));	682	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
624		683
625	assert (elen <= MAX_LBL_SIZE);	684	assert (elen <= MAX_LBL_SIZE);
626		685
627	(*pkt)[offs] = elen;	686	(*pkt)[offs] = elen;
628	offs += elen + 1;	687	offs += elen + 1;
629	append_domain (*pkt, offs, THISNODE->domain);	688	append_domain (*pkt, offs, dns->c->conf->domain);
630		689
631	(*pkt)[offs++] = 0;	690	(*pkt)[offs++] = 0;
632	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;	691	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
633	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	692	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
634		693
…		…
657	delete pkt;	716	delete pkt;
658	}	717	}
659		718
660	/////////////////////////////////////////////////////////////////////////////	719	/////////////////////////////////////////////////////////////////////////////
661		720
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)	721	dns_connection::dns_connection (connection *c)
688	: c (c)	722	: c (c)
689	, rcvdq (MAX_BACKLOG * 2)	723	, rcvdq (MAX_BACKLOG * 2)
690	, snddq (MAX_BACKLOG * 2)	724	, snddq (MAX_BACKLOG * 2)
691	, tw (this, &dns_connection::time_cb)	725	, tw (this, &dns_connection::time_cb)
…		…
696		730
697	rcvseq = sndseq = 0;	731	rcvseq = sndseq = 0;
698		732
699	last_sent = last_received = 0;	733	last_sent = last_received = 0;
700	poll_interval = MIN_POLL_INTERVAL;	734	poll_interval = MIN_POLL_INTERVAL;
701	send_interval = 0.2; // starting rate	735	send_interval = 0.5; // starting rate
		736	min_latency = INITIAL_TIMEOUT;
702	}	737	}
703		738
704	dns_connection::~dns_connection ()	739	dns_connection::~dns_connection ()
705	{	740	{
706	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	741	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
…		…
714	if (r->datalen)	749	if (r->datalen)
715	{	750	{
716	last_received = NOW;	751	last_received = NOW;
717	tw.trigger ();	752	tw.trigger ();
718		753
719	poll_interval *= 0.99;	754	poll_interval = send_interval;
720	if (poll_interval > MIN_POLL_INTERVAL)
721	poll_interval = MIN_POLL_INTERVAL;
722	}	755	}
723	else	756	else
724	{	757	{
725	poll_interval *= 1.1;	758	poll_interval *= 1.5;
		759
726	if (poll_interval > MAX_POLL_INTERVAL)	760	if (poll_interval > MAX_POLL_INTERVAL)
727	poll_interval = MAX_POLL_INTERVAL;	761	poll_interval = MAX_POLL_INTERVAL;
728	}	762	}
729		763
730	rcvpq.push_back (r);	764	rcvpq.push_back (r);
…		…
748	}	782	}
749		783
750	rcvseq = (rcvseq + 1) & SEQNO_MASK;	784	rcvseq = (rcvseq + 1) & SEQNO_MASK;
751		785
752	if (!rcvdq.put (r->data, r->datalen))	786	if (!rcvdq.put (r->data, r->datalen))
		787	{
		788	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
753	abort (); // MUST never overflow, can be caused by data corruption, TODO	789	abort (); // MUST never overflow, can be caused by data corruption, TODO
		790	}
754		791
755	while (vpn_packet *pkt = rcvdq.get ())	792	while (vpn_packet *pkt = rcvdq.get ())
756	{	793	{
757	sockinfo si;	794	sockinfo si;
758	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	795	si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4;
759		796
760	vpn->recv_vpn_packet (pkt, si);	797	vpn->recv_vpn_packet (pkt, si);
761		798
762	delete pkt;	799	delete pkt;
763	}	800	}
…		…
777	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	814	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
778		815
779	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))	816	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
780	&& pkt.qdcount == htons (1))	817	&& pkt.qdcount == htons (1))
781	{	818	{
782	char qname[MAXSIZE];	819	char qname [MAXSIZE];
783	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);	820	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
784		821
785	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];	822	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
786	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];	823	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
787		824
788	pkt.qdcount = htons (1);	825	pkt.qdcount = htons (1);
789	pkt.ancount = 0;	826	pkt.ancount = 0;
790	pkt.nscount = 0; // should be self, as other nameservers reply like this	827	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	828	pkt.arcount = 0; // a record for self, as other nameservers reply like this
792		829
793	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	830	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
794		831
795	int dlen = strlen (THISNODE->domain);	832	int dlen = strlen (THISNODE->domain);
796		833
797	if (qclass == RR_CLASS_IN	834	if (qclass == RR_CLASS_IN
798	&& qlen > dlen + 1	835	&& qlen > dlen + 1
799	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	836	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
800	{	837	{
801	// now generate reply	838	// now generate reply
802	pkt.ancount = htons (1); // one answer RR	839	pkt.ancount = htons (1); // one answer RR
803	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	840	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
804		841
…		…
817	if (0 < client && client <= conns.size ())	854	if (0 < client && client <= conns.size ())
818	{	855	{
819	connection *c = conns [client - 1];	856	connection *c = conns [client - 1];
820	dns_connection *dns = c->dns;	857	dns_connection *dns = c->dns;
821	dns_rcv *rcv;	858	dns_rcv *rcv;
		859	bool in_seq;
822		860
823	if (dns)	861	if (dns)
824	{	862	{
825	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )	863	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
826	if (SEQNO_EQ ((*i)->seqno, seqno))	864	if (SEQNO_EQ ((*i)->seqno, seqno))
827	{	865	{
828	// already seen that request: simply reply with the cached reply	866	// already seen that request: simply reply with the cached reply
829	dns_rcv r = i;	867	dns_rcv r = i;
830		868
831	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	869	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		870
		871	// refresh header & id, as the retry count could have changed
		872	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		873	r->pkt->id = pkt.id;
832		874
833	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);	875	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
834	pkt.id = r->pkt->id;	876
835	goto duplicate_request;	877	goto duplicate_request;
836	}	878	}
		879
		880	in_seq = dns->rcvseq == seqno;
837		881
838	// new packet, queue	882	// new packet, queue
839	rcv = new dns_rcv (seqno, data, datalen);	883	rcv = new dns_rcv (seqno, data, datalen);
840	dns->receive_rep (rcv);	884	dns->receive_rep (rcv);
841	}	885	}
842		886
		887	{
843	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section	888	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
844		889
845	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;	890	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
846	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type	891	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
847	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	892	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
848	pkt [offs++] = 0; pkt [offs++] = 0;	893	pkt [offs++] = 0; pkt [offs++] = 0;
849	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL	894	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
850		895
851	int rdlen_offs = offs += 2;	896	int rdlen_offs = offs += 2;
852		897
		898	if (dns)
		899	{
853	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;	900	int dlen = ntohs (dns->cfg.max_size) - offs;
		901
854	// bind doesn't compress well, so reduce further by one label length	902	// bind doesn't compress well, so reduce further by one label length
855	dlen -= qlen;	903	dlen -= qlen;
856		904
857	if (dns)	905	// only put data into in-order sequence packets, if
858	{	906	// we receive out-of-order packets we generate empty
		907	// replies
859	while (dlen > 1 && !dns->snddq.empty ())	908	while (dlen > 1 && !dns->snddq.empty () && in_seq)
860	{	909	{
861	int txtlen = dlen <= 255 ? dlen - 1 : 255;	910	int txtlen = dlen <= 255 ? dlen - 1 : 255;
862		911
863	if (txtlen > dns->snddq.size ())	912	if (txtlen > dns->snddq.size ())
864	txtlen = dns->snddq.size ();	913	txtlen = dns->snddq.size ();
865		914
866	pkt[offs++] = txtlen;	915	pkt[offs++] = txtlen;
867	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);	916	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
868	offs += txtlen;	917	offs += txtlen;
869	dns->snddq.remove (txtlen);	918	dns->snddq.remove (txtlen);
870		919
871	dlen -= txtlen + 1;	920	dlen -= txtlen + 1;
872	}	921	}
873		922
874	// avoid empty TXT rdata	923	// avoid empty TXT rdata
875	if (offs == rdlen_offs)	924	if (offs == rdlen_offs)
876	pkt[offs++] = 0;	925	pkt[offs++] = 0;
		926
		927	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
877	}	928	}
878	else	929	else
879	{	930	{
880	// send RST	931	// send RST
881	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	932	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
882	pkt [offs++] = CMD_IP_RST;	933	pkt [offs++] = CMD_IP_RST;
883	}	934	}
884		935
885	int rdlen = offs - rdlen_offs;	936	int rdlen = offs - rdlen_offs;
886		937
887	pkt [rdlen_offs - 2] = rdlen >> 8;	938	pkt [rdlen_offs - 2] = rdlen >> 8;
888	pkt [rdlen_offs - 1] = rdlen;	939	pkt [rdlen_offs - 1] = rdlen;
889		940
890	if (dns)	941	if (dns)
891	{	942	{
892	// now update dns_rcv copy	943	// now update dns_rcv copy
893	rcv->pkt->len = offs;	944	rcv->pkt->len = offs;
894	memcpy (rcv->pkt->at (0), pkt.at (0), offs);	945	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
895	}	946	}
		947	}
896		948
897	duplicate_request: ;	949	duplicate_request: ;
898	}	950	}
899	else	951	else
900	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	952	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
…		…
912	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	964	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
913	pkt [offs++] = 0; pkt [offs++] = 0;	965	pkt [offs++] = 0; pkt [offs++] = 0;
914	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL	966	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
915	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength	967	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
916		968
917	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);	969	slog (L_INFO, _("DNS: client %d connects"), client);
918		970
919	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	971	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
920	pkt [offs++] = CMD_IP_REJ;	972	pkt [offs++] = CMD_IP_REJ;
921		973
922	if (0 < client && client <= conns.size ())	974	if (0 < client && client <= conns.size ())
…		…
953	i != dns_sndpq.end ();	1005	i != dns_sndpq.end ();
954	++i)	1006	++i)
955	if ((*i)->pkt->id == pkt.id)	1007	if ((*i)->pkt->id == pkt.id)
956	{	1008	{
957	dns_connection dns = (i)->dns;	1009	dns_connection dns = (i)->dns;
		1010	connection *c = dns->c;
958	int seqno = (*i)->seqno;	1011	int seqno = (*i)->seqno;
959	u8 data[MAXSIZE], *datap = data;	1012	u8 data[MAXSIZE], *datap = data;
960		1013
961	if ((*i)->retry)	1014	if ((*i)->retry)
962	{	1015	{
963	dns->send_interval *= 1.01;	1016	dns->send_interval *= 1.01;
964	if (dns->send_interval < MAX_SEND_INTERVAL)	1017	if (dns->send_interval > MAX_SEND_INTERVAL)
965	dns->send_interval = MAX_SEND_INTERVAL;	1018	dns->send_interval = MAX_SEND_INTERVAL;
966	}	1019	}
967	else	1020	else
968	{	1021	{
		1022	#if 0
969	dns->send_interval *= 0.99;	1023	dns->send_interval *= 0.999;
		1024	#endif
		1025	// the latency surely puts an upper bound on
		1026	// the minimum send interval
		1027	double latency = NOW - (*i)->sent;
		1028
		1029	if (latency < dns->min_latency)
		1030	dns->min_latency = latency;
		1031
		1032	if (dns->send_interval > dns->min_latency * LATENCY_FACTOR)
		1033	dns->send_interval = dns->min_latency * LATENCY_FACTOR;
		1034
970	if (dns->send_interval < MIN_SEND_INTERVAL)	1035	if (dns->send_interval < MIN_SEND_INTERVAL)
971	dns->send_interval = MIN_SEND_INTERVAL;	1036	dns->send_interval = MIN_SEND_INTERVAL;
972
973	// the latency surely puts an upper bound on
974	// the minimum send interval
975	if (dns->send_interval > NOW - (*i)->sent)
976	dns->send_interval = NOW - (*i)->sent;
977	}	1037	}
978		1038
979	delete *i;	1039	delete *i;
980	dns_sndpq.erase (i);	1040	dns_sndpq.erase (i);
981		1041
…		…
1031		1091
1032	if (ip [0] == CMD_IP_1	1092	if (ip [0] == CMD_IP_1
1033	&& ip [1] == CMD_IP_2	1093	&& ip [1] == CMD_IP_2
1034	&& ip [2] == CMD_IP_3)	1094	&& ip [2] == CMD_IP_3)
1035	{	1095	{
1036	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);	1096	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1037		1097
1038	if (ip [3] == CMD_IP_RST)	1098	if (ip [3] == CMD_IP_RST)
1039	{	1099	{
1040	slog (L_DEBUG, _("got tunnel RST request"));	1100	slog (L_DEBUG, _("DNS: got tunnel RST request"));
1041		1101
1042	connection *c = dns->c;
1043	delete c->dns; c->dns = 0;	1102	delete dns; c->dns = 0;
1044		1103
1045	return;	1104	return;
1046	}	1105	}
1047	else if (ip [3] == CMD_IP_SYN)	1106	else if (ip [3] == CMD_IP_SYN)
		1107	{
		1108	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1048	dns->established = true;	1109	dns->established = true;
		1110	}
		1111	else if (ip [3] == CMD_IP_REJ)
		1112	{
		1113	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1114	abort ();
		1115	}
1049	else	1116	else
1050	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);	1117	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1051	}	1118	}
1052	else	1119	else
1053	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),	1120	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1054	ip [0], ip [1], ip [2], ip [3]);	1121	ip [0], ip [1], ip [2], ip [3]);
1055		1122
1056	return;	1123	return;
1057	}	1124	}
1058		1125
1059	int client, rseqno;	1126	int client, rseqno;
1060	decode_header (qname, client, rseqno);	1127	decode_header (qname, client, rseqno);
1061		1128
1062	if (client != THISNODE->id)	1129	if (client != THISNODE->id)
1063	{	1130	{
1064	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));	1131	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1065	datap = 0;	1132	datap = 0;
1066	}	1133	}
1067	else if (rseqno != seqno)	1134	else if (rseqno != seqno)
1068	{	1135	{
1069	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));	1136	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
1070	datap = 0;	1137	datap = 0;
1071	}	1138	}
1072	}	1139	}
1073	}	1140	}
1074		1141
…		…
1091		1158
1092	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);	1159	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1093		1160
1094	if (pkt->len > 0)	1161	if (pkt->len > 0)
1095	{	1162	{
1096	if (THISNODE->dns_port)	1163	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1164	dnsv4_client (*pkt);
		1165	else
1097	{	1166	{
1098	dnsv4_server (*pkt);	1167	dnsv4_server (*pkt);
1099	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);	1168	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1100	}	1169	}
1101	else
1102	dnsv4_client (*pkt);
1103		1170
1104	delete pkt;	1171	delete pkt;
1105	}	1172	}
1106	}	1173	}
1107	}	1174	}
1108		1175
1109	bool	1176	bool
1110	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1177	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1111	{	1178	{
		1179	int client = ntohs (si.port);
		1180
		1181	assert (0 < client && client <= conns.size ());
		1182
		1183	connection *c = conns [client - 1];
		1184
1112	if (!dns)	1185	if (!c->dns)
1113	dns = new dns_connection (this);	1186	c->dns = new dns_connection (c);
1114		1187
1115	if (!dns->snddq.put (pkt))	1188	if (!c->dns->snddq.put (pkt))
1116	return false;	1189	return false;
1117		1190
1118	dns->tw.trigger ();	1191	c->dns->tw.trigger ();
1119		1192
1120	return true;	1193	return true;
		1194	}
		1195
		1196	void
		1197	connection::dnsv4_reset_connection ()
		1198	{
		1199	//delete dns; dns = 0; //TODO
1121	}	1200	}
1122		1201
1123	#define NEXT(w) do { if (next > (w)) next = w; } while (0)	1202	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1124		1203
1125	void	1204	void
…		…
1144	if (!send)	1223	if (!send)
1145	{	1224	{
1146	send = r;	1225	send = r;
1147		1226
1148	r->retry++;	1227	r->retry++;
1149	r->timeout = NOW + r->retry;	1228	r->timeout = NOW + (r->retry * min_latency * 8.);
		1229
		1230	// the following code changes the query section a bit, forcing
		1231	// the forwarder to generate a new request
		1232	if (r->stdhdr)
		1233	{
		1234	//printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
		1235	//encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
		1236	}
1150	}	1237	}
1151	}	1238	}
1152	else	1239	else
1153	NEXT (r->timeout);	1240	NEXT (r->timeout);
1154	}	1241	}
1155		1242
1156	if (last_sent + send_interval <= NOW)	1243	if (send \|\| (last_sent + send_interval <= NOW))
1157	{	1244	{
1158	if (!send)	1245	if (!send)
1159	{	1246	{
1160	// generate a new packet, if wise	1247	// generate a new packet, if wise
1161		1248
…		…
1164	if (vpn->dns_sndpq.empty ())	1251	if (vpn->dns_sndpq.empty ())
1165	{	1252	{
1166	send = new dns_snd (this);	1253	send = new dns_snd (this);
1167		1254
1168	cfg.reset (THISNODE->id);	1255	cfg.reset (THISNODE->id);
1169	send->gen_syn_req (cfg);	1256	send->gen_syn_req ();
1170	}	1257	}
1171	}	1258	}
1172	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)	1259	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
		1260	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1173	{	1261	{
		1262	//printf ("sending data request etc.\n"); //D
		1263	if (!snddq.empty () \|\| last_received + 1. > NOW)
		1264	{
		1265	poll_interval = send_interval;
		1266	NEXT (NOW + send_interval);
		1267	}
		1268
1174	send = new dns_snd (this);	1269	send = new dns_snd (this);
1175	send->gen_stream_req (sndseq, snddq);	1270	send->gen_stream_req (sndseq, snddq);
		1271	send->timeout = NOW + min_latency * 8.;
1176		1272
1177	sndseq = (sndseq + 1) & SEQNO_MASK;	1273	sndseq = (sndseq + 1) & SEQNO_MASK;
1178	}	1274	}
1179		1275
1180	if (send)	1276	if (send && !send->retry)
1181	vpn->dns_sndpq.push_back (send);	1277	vpn->dns_sndpq.push_back (send);
1182	}	1278	}
1183		1279
1184	if (send)	1280	if (send)
1185	{	1281	{
1186	last_sent = NOW;	1282	last_sent = NOW;
1187
1188	sendto (vpn->dnsv4_fd,	1283	sendto (vpn->dnsv4_fd,
1189	send->pkt->at (0), send->pkt->len, 0,	1284	send->pkt->at (0), send->pkt->len, 0,
1190	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1285	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1191	}	1286	}
1192	}	1287	}
1193	else	1288	else
1194	NEXT (last_sent + send_interval);	1289	NEXT (last_sent + send_interval);
1195		1290
1196	//printf ("pi %f si %f N %f (%d:%d)\n", poll_interval, send_interval, next - NOW, vpn->dns_sndpq.size (), snddq.size ());	1291	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1292	poll_interval, send_interval, next - NOW,
		1293	vpn->dns_sndpq.size (), snddq.size (),
		1294	rcvpq.size ());
1197		1295
1198	// TODO: no idea when this happens, but when next < NOW, we have a problem	1296	// TODO: no idea when this happens, but when next < NOW, we have a problem
1199	if (next < NOW + 0.0001)	1297	if (next < NOW + 0.0001)
1200	next = NOW + 0.1;	1298	next = NOW + 0.1;
1201		1299

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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 1.27 by pcg, Sat Mar 12 18:10:40 2005 UTC

Diff Legend

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.11 by pcg, Fri Mar 4 08:45:24 2005 UTC vs.
Revision 1.27 by pcg, Sat Mar 12 18:10:40 2005 UTC