[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 1.35 by pcg, Wed Mar 16 14:56:32 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 .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	49	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
50	#define ACTIVITY_INTERVAL 5.	50	#define ACTIVITY_INTERVAL 5.
51		51
		52	#define TIMEOUT_FACTOR 2.
		53
52	#define INITIAL_TIMEOUT 1. // retry timeouts	54	#define INITIAL_TIMEOUT 0.1 // retry timeouts
53	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn	55	#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn
54		56
55	#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests	57	#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
56	#define MAX_SEND_INTERVAL 0.5 // optimistic?	58	#define MAX_SEND_INTERVAL 2. // optimistic?
57		59
		60	#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
58	#define MAX_OUTSTANDING 40 // max. outstanding requests	61	#define MAX_OUTSTANDING 100 // max. outstanding requests
59	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING	62	#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	63	#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
61		64
62	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	65	#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	66	// 240 leaves about 4 bytes of server reply data
64	// every two request bytes less give room for one reply byte	67	// every request byte less give room for two reply bytes
65		68
66	#define SEQNO_MASK 0xffff	69	#define SEQNO_MASK 0x3fff
67	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	70	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
68		71
69	#define MAX_LBL_SIZE 63	72	#define MAX_LBL_SIZE 63
70	#define MAX_PKT_SIZE 512	73	#define MAX_PKT_SIZE 512
71		74
…		…
264	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	267	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
265		268
266	/////////////////////////////////////////////////////////////////////////////	269	/////////////////////////////////////////////////////////////////////////////
267		270
268	#define HDRSIZE 6	271	#define HDRSIZE 6
269		272
270	inline void encode_header (char *data, int clientid, int seqno)	273	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
271	{	274	{
272	u8 hdr[3] = { clientid, seqno >> 8, seqno };	275	seqno &= SEQNO_MASK;
		276
		277	u8 hdr[3] = {
		278	clientid,
		279	(seqno >> 8) \| (retry << 6),
		280	seqno,
		281	};
273		282
274	assert (clientid < 256);	283	assert (clientid < 256);
275		284
276	cdc26.encode (data, hdr, 3);	285	cdc26.encode (data, hdr, 3);
277	}	286	}
…		…
281	u8 hdr[3];	290	u8 hdr[3];
282		291
283	cdc26.decode (hdr, data, HDRSIZE);	292	cdc26.decode (hdr, data, HDRSIZE);
284		293
285	clientid = hdr[0];	294	clientid = hdr[0];
286	seqno = (hdr[1] << 8) \| hdr[2];	295	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
287	}	296	}
288		297
289	/////////////////////////////////////////////////////////////////////////////	298	/////////////////////////////////////////////////////////////////////////////
290		299
291	struct byte_stream	300	struct byte_stream
…		…
320	}	329	}
321		330
322	void byte_stream::remove (int count)	331	void byte_stream::remove (int count)
323	{	332	{
324	if (count > fill)	333	if (count > fill)
325	abort ();	334	assert (count <= fill);
326		335
327	memmove (data, data + count, fill -= count);	336	memmove (data, data + count, fill -= count);
328	}	337	}
329		338
330	bool byte_stream::put (u8 *data, unsigned int datalen)	339	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
350	return true;	359	return true;
351	}	360	}
352		361
353	vpn_packet *byte_stream::get ()	362	vpn_packet *byte_stream::get ()
354	{	363	{
		364	unsigned int len;
		365
		366	for (;;)
		367	{
355	unsigned int len = (data [0] << 8) \| data [1];	368	len = (data [0] << 8) \| data [1];
356		369
357	if (len > MAXSIZE && fill >= 2)	370	if (len <= MAXSIZE \|\| fill < 2)
358	abort (); // TODO handle this gracefully, connection reset	371	break;
359		372
		373	// TODO: handle this better than skipping, e.g. by reset
		374	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		375	remove (1);
		376	}
		377
360	if (fill < len + 2)	378	if (fill < len + 2)
361	return 0;	379	return 0;
362		380
363	vpn_packet *pkt = new vpn_packet;	381	vpn_packet *pkt = new vpn_packet;
364		382
…		…
393	struct dns_cfg	411	struct dns_cfg
394	{	412	{
395	static int next_uid;	413	static int next_uid;
396		414
397	u8 id1, id2, id3, id4;	415	u8 id1, id2, id3, id4;
		416
398	u8 version;	417	u8 version;
		418	u8 flags;
399	u8 rrtype;	419	u8 rrtype;
400	u8 flags;
401	u8 def_ttl;	420	u8 def_ttl;
402	u8 rcv_cdc;	421
403	u8 snd_cdc;
404	u16 max_size;
405	u16 client;	422	u16 client;
406	u16 uid; // to make request unique	423	u16 uid; // to make request unique
407		424
408	u8 reserved[8];	425	u16 max_size;
		426	u8 seq_cdc;
		427	u8 req_cdc;
		428
		429	u8 rep_cdc;
		430	u8 delay; // time in 0.01s units that the server may delay replying packets
		431	u8 r3, r4;
		432
		433	u8 r5, r6, r7, r8;
409		434
410	void reset (int clientid);	435	void reset (int clientid);
411	bool valid ();	436	bool valid ();
412	};	437	};
413		438
…		…
423	version = 1;	448	version = 1;
424		449
425	rrtype = RR_TYPE_TXT;	450	rrtype = RR_TYPE_TXT;
426	flags = 0;	451	flags = 0;
427	def_ttl = 0;	452	def_ttl = 0;
		453	seq_cdc = 26;
		454	req_cdc = 62;
428	rcv_cdc = 0;	455	rep_cdc = 0;
429	snd_cdc = 62;
430	max_size = ntohs (MAX_PKT_SIZE);	456	max_size = htons (MAX_PKT_SIZE);
431	client = ntohs (clientid);	457	client = htons (clientid);
432	uid = next_uid++;	458	uid = next_uid++;
		459	delay = 0;
433		460
434	memset (reserved, 0, 8);	461	r3 = r4 = 0;
		462	r4 = r5 = r6 = r7 = 0;
435	}	463	}
436		464
437	bool dns_cfg::valid ()	465	bool dns_cfg::valid ()
438	{	466	{
439	return id1 == 'G'	467	return id1 == 'G'
440	&& id2 == 'V'	468	&& id2 == 'V'
441	&& id3 == 'P'	469	&& id3 == 'P'
442	&& id4 == 'E'	470	&& id4 == 'E'
		471	&& seq_cdc == 26
		472	&& req_cdc == 62
		473	&& rep_cdc == 0
443	&& version == 1	474	&& version == 1;
444	&& flags == 0
445	&& rcv_cdc == 0
446	&& snd_cdc == 62
447	&& max_size == ntohs (MAX_PKT_SIZE);
448	}	475	}
449		476
450	struct dns_packet : net_packet	477	struct dns_packet : net_packet
451	{	478	{
452	u16 id;	479	u16 id;
453	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	480	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
454	u16 qdcount, ancount, nscount, arcount;	481	u16 qdcount, ancount, nscount, arcount;
455		482
456	u8 data[MAXSIZE - 6 * 2];	483	u8 data [MAXSIZE - 6 * 2];
457		484
458	int decode_label (char *data, int size, int &offs);	485	int decode_label (char *data, int size, int &offs);
459	};	486	};
460		487
461	int dns_packet::decode_label (char *data, int size, int &offs)	488	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
492	return data - orig;	519	return data - orig;
493	}	520	}
494		521
495	/////////////////////////////////////////////////////////////////////////////	522	/////////////////////////////////////////////////////////////////////////////
496		523
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	524	static u16 dns_id = 0; // TODO: should be per-vpn
513		525
514	static u16 next_id ()	526	static u16 next_id ()
515	{	527	{
		528	if (!dns_id)
		529	dns_id = time (0);
		530
516	// the simplest lsfr with periodicity 65535 i could find	531	// the simplest lsfr with periodicity 65535 i could find
517	dns_id = (dns_id << 1)	532	dns_id = (dns_id << 1)
518	\| (((dns_id >> 1)	533	\| (((dns_id >> 1)
519	^ (dns_id >> 2)	534	^ (dns_id >> 2)
520	^ (dns_id >> 4)	535	^ (dns_id >> 4)
521	^ (dns_id >> 15)) & 1);	536	^ (dns_id >> 15)) & 1);
522		537
523	return dns_id;	538	return dns_id;
524	}	539	}
525		540
		541	struct dns_rcv;
		542	struct dns_snd;
		543
		544	struct dns_connection
		545	{
		546	connection *c;
		547	struct vpn *vpn;
		548
		549	dns_cfg cfg;
		550
		551	bool established;
		552
		553	tstamp last_received;
		554	tstamp last_sent;
		555	double min_latency;
		556	double poll_interval, send_interval;
		557
		558	vector<dns_rcv *> rcvpq;
		559
		560	byte_stream rcvdq; int rcvseq; int repseq;
		561	byte_stream snddq; int sndseq;
		562
		563	void time_cb (time_watcher &w); time_watcher tw;
		564	void receive_rep (dns_rcv *r);
		565
		566	dns_connection (connection *c);
		567	~dns_connection ();
		568	};
		569
		570	struct dns_snd
		571	{
		572	dns_packet *pkt;
		573	tstamp timeout, sent;
		574	int retry;
		575	struct dns_connection *dns;
		576	int seqno;
		577	bool stdhdr;
		578
		579	void gen_stream_req (int seqno, byte_stream &stream);
		580	void gen_syn_req ();
		581
		582	dns_snd (dns_connection *dns);
		583	~dns_snd ();
		584	};
		585
526	dns_snd::dns_snd (dns_connection *dns)	586	dns_snd::dns_snd (dns_connection *dns)
527	: dns (dns)	587	: dns (dns)
528	{	588	{
529	timeout = 0;	589	timeout = 0;
530	retry = 0;	590	retry = 0;
531	seqno = 0;	591	seqno = 0;
532	sent = NOW;	592	sent = NOW;
		593	stdhdr = false;
533		594
534	pkt = new dns_packet;	595	pkt = new dns_packet;
535		596
536	pkt->id = next_id ();	597	pkt->id = next_id ();
537	}	598	}
…		…
564	}	625	}
565	}	626	}
566		627
567	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)	628	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
568	{	629	{
		630	stdhdr = true;
569	this->seqno = seqno;	631	this->seqno = seqno;
570		632
571	timeout = NOW + INITIAL_TIMEOUT;	633	timeout = NOW + INITIAL_TIMEOUT;
572		634
573	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	635	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
574	pkt->qdcount = htons (1);	636	pkt->qdcount = htons (1);
575		637
576	int offs = 6*2;	638	int offs = 6*2;
577	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	639	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,	640	// 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	641	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
580		642
581	char enc[256], *encp = enc;	643	char enc[256], *encp = enc;
582	encode_header (enc, THISNODE->id, seqno);	644	encode_header (enc, THISNODE->id, seqno);
…		…
600	encp += lbllen;	662	encp += lbllen;
601		663
602	enclen -= lbllen;	664	enclen -= lbllen;
603	}	665	}
604		666
605	append_domain (*pkt, offs, THISNODE->domain);	667	append_domain (*pkt, offs, dns->c->conf->domain);
606		668
607	(*pkt)[offs++] = 0;	669	(*pkt)[offs++] = 0;
608	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	670	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
609	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	671	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
610		672
611	pkt->len = offs;	673	pkt->len = offs;
612	}	674	}
613		675
614	void dns_snd::gen_syn_req (const dns_cfg &cfg)	676	void dns_snd::gen_syn_req ()
615	{	677	{
616	timeout = NOW + INITIAL_SYN_TIMEOUT;	678	timeout = NOW + INITIAL_SYN_TIMEOUT;
617		679
618	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	680	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
619	pkt->qdcount = htons (1);	681	pkt->qdcount = htons (1);
620		682
621	int offs = 6*2;	683	int offs = 6 * 2;
622		684
623	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));	685	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
624		686
625	assert (elen <= MAX_LBL_SIZE);	687	assert (elen <= MAX_LBL_SIZE);
626		688
627	(*pkt)[offs] = elen;	689	(*pkt)[offs] = elen;
628	offs += elen + 1;	690	offs += elen + 1;
629	append_domain (*pkt, offs, THISNODE->domain);	691	append_domain (*pkt, offs, dns->c->conf->domain);
630		692
631	(*pkt)[offs++] = 0;	693	(*pkt)[offs++] = 0;
632	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;	694	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
633	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	695	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
634		696
…		…
657	delete pkt;	719	delete pkt;
658	}	720	}
659		721
660	/////////////////////////////////////////////////////////////////////////////	722	/////////////////////////////////////////////////////////////////////////////
661		723
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)	724	dns_connection::dns_connection (connection *c)
688	: c (c)	725	: c (c)
689	, rcvdq (MAX_BACKLOG * 2)	726	, rcvdq (MAX_BACKLOG * 2)
690	, snddq (MAX_BACKLOG * 2)	727	, snddq (MAX_BACKLOG)
691	, tw (this, &dns_connection::time_cb)	728	, tw (this, &dns_connection::time_cb)
692	{	729	{
693	vpn = c->vpn;	730	vpn = c->vpn;
694		731
695	established = false;	732	established = false;
696		733
697	rcvseq = sndseq = 0;	734	rcvseq = repseq = sndseq = 0;
698		735
699	last_sent = last_received = 0;	736	last_sent = last_received = 0;
700	poll_interval = MIN_POLL_INTERVAL;	737	poll_interval = 0.5; // starting here
701	send_interval = 0.2; // starting rate	738	send_interval = 0.5; // starting rate
		739	min_latency = INITIAL_TIMEOUT;
702	}	740	}
703		741
704	dns_connection::~dns_connection ()	742	dns_connection::~dns_connection ()
705	{	743	{
706	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	744	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
…		…
718		756
719	poll_interval = send_interval;	757	poll_interval = send_interval;
720	}	758	}
721	else	759	else
722	{	760	{
723	poll_interval *= 1.1;	761	poll_interval *= 1.5;
		762
724	if (poll_interval > MAX_POLL_INTERVAL)	763	if (poll_interval > MAX_POLL_INTERVAL)
725	poll_interval = MAX_POLL_INTERVAL;	764	poll_interval = MAX_POLL_INTERVAL;
726	}	765	}
727		766
728	rcvpq.push_back (r);	767	rcvpq.push_back (r);
…		…
746	}	785	}
747		786
748	rcvseq = (rcvseq + 1) & SEQNO_MASK;	787	rcvseq = (rcvseq + 1) & SEQNO_MASK;
749		788
750	if (!rcvdq.put (r->data, r->datalen))	789	if (!rcvdq.put (r->data, r->datalen))
		790	{
		791	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
751	abort (); // MUST never overflow, can be caused by data corruption, TODO	792	abort (); // MUST never overflow, can be caused by data corruption, TODO
		793	}
752		794
753	while (vpn_packet *pkt = rcvdq.get ())	795	while (vpn_packet *pkt = rcvdq.get ())
754	{	796	{
755	sockinfo si;	797	sockinfo si;
756	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	798	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
757		799
758	vpn->recv_vpn_packet (pkt, si);	800	vpn->recv_vpn_packet (pkt, si);
759		801
760	delete pkt;	802	delete pkt;
761	}	803	}
…		…
775	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	817	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
776		818
777	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))	819	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
778	&& pkt.qdcount == htons (1))	820	&& pkt.qdcount == htons (1))
779	{	821	{
780	char qname[MAXSIZE];	822	char qname [MAXSIZE];
781	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);	823	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
782		824
783	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];	825	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
784	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];	826	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
785		827
786	pkt.qdcount = htons (1);	828	pkt.qdcount = htons (1);
787	pkt.ancount = 0;	829	pkt.ancount = 0;
788	pkt.nscount = 0; // should be self, as other nameservers reply like this	830	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	831	pkt.arcount = 0; // a record for self, as other nameservers reply like this
790		832
791	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	833	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
792		834
793	int dlen = strlen (THISNODE->domain);	835	int dlen = strlen (THISNODE->domain);
794		836
795	if (qclass == RR_CLASS_IN	837	if (qclass == RR_CLASS_IN
796	&& qlen > dlen + 1	838	&& qlen > dlen + 1
797	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	839	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
798	{	840	{
799	// now generate reply	841	// now generate reply
800	pkt.ancount = htons (1); // one answer RR	842	pkt.ancount = htons (1); // one answer RR
801	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	843	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
802		844
…		…
824	if (SEQNO_EQ ((*i)->seqno, seqno))	866	if (SEQNO_EQ ((*i)->seqno, seqno))
825	{	867	{
826	// already seen that request: simply reply with the cached reply	868	// already seen that request: simply reply with the cached reply
827	dns_rcv r = i;	869	dns_rcv r = i;
828		870
829	slog (L_DEBUG, "DUPLICATE %d\n", htons (r->pkt->id));	871	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		872
		873	// refresh header & id, as the retry count could have changed
		874	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		875	r->pkt->id = pkt.id;
830		876
831	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);	877	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
832	pkt.id = r->pkt->id;	878
833	goto duplicate_request;	879	goto duplicate_request;
834	}	880	}
835		881
836	// new packet, queue	882	// new packet, queue
837	rcv = new dns_rcv (seqno, data, datalen);	883	rcv = new dns_rcv (seqno, data, datalen);
838	dns->receive_rep (rcv);	884	dns->receive_rep (rcv);
839	}	885	}
840		886
		887	{
841	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
842		889
843	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;	890	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
844	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type	891	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
845	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
846	pkt [offs++] = 0; pkt [offs++] = 0;	893	pkt [offs++] = 0; pkt [offs++] = 0;
847	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
848		895
849	int rdlen_offs = offs += 2;	896	int rdlen_offs = offs += 2;
850		897
		898	if (dns)
		899	{
851	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;	900	int dlen = ntohs (dns->cfg.max_size) - offs;
		901
852	// 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
853	dlen -= qlen;	903	dlen -= qlen;
854		904
855	if (dns)	905	// only put data into in-order sequence packets, if
856	{	906	// we receive out-of-order packets we generate empty
857	while (dlen > 1 && !dns->snddq.empty ())	907	// replies
		908	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		909	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
858	{	910	{
		911	dns->repseq = seqno;
		912
		913	while (dlen > 1 && !dns->snddq.empty ())
		914	{
859	int txtlen = dlen <= 255 ? dlen - 1 : 255;	915	int txtlen = dlen <= 255 ? dlen - 1 : 255;
860		916
861	if (txtlen > dns->snddq.size ())	917	if (txtlen > dns->snddq.size ())
862	txtlen = dns->snddq.size ();	918	txtlen = dns->snddq.size ();
863		919
864	pkt[offs++] = txtlen;	920	pkt[offs++] = txtlen;
865	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);	921	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
866	offs += txtlen;	922	offs += txtlen;
867	dns->snddq.remove (txtlen);	923	dns->snddq.remove (txtlen);
868		924
869	dlen -= txtlen + 1;	925	dlen -= txtlen + 1;
		926	}
870	}	927	}
871		928
872	// avoid empty TXT rdata	929	// avoid completely empty TXT rdata
873	if (offs == rdlen_offs)	930	if (offs == rdlen_offs)
874	pkt[offs++] = 0;	931	pkt[offs++] = 0;
875		932
876	slog (L_NOISE, "snddq %d", dns->snddq.size ());	933	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
877	}	934	}
878	else	935	else
879	{	936	{
880	// send RST	937	// send RST
881	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	938	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
882	pkt [offs++] = CMD_IP_RST;	939	pkt [offs++] = CMD_IP_RST;
883	}	940	}
884		941
885	int rdlen = offs - rdlen_offs;	942	int rdlen = offs - rdlen_offs;
886		943
887	pkt [rdlen_offs - 2] = rdlen >> 8;	944	pkt [rdlen_offs - 2] = rdlen >> 8;
888	pkt [rdlen_offs - 1] = rdlen;	945	pkt [rdlen_offs - 1] = rdlen;
889		946
890	if (dns)	947	if (dns)
891	{	948	{
892	// now update dns_rcv copy	949	// now update dns_rcv copy
893	rcv->pkt->len = offs;	950	rcv->pkt->len = offs;
894	memcpy (rcv->pkt->at (0), pkt.at (0), offs);	951	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
895	}	952	}
		953	}
896		954
897	duplicate_request: ;	955	duplicate_request: ;
898	}	956	}
899	else	957	else
900	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	958	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
…		…
912	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	970	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
913	pkt [offs++] = 0; pkt [offs++] = 0;	971	pkt [offs++] = 0; pkt [offs++] = 0;
914	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL	972	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
915	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength	973	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
916		974
917	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);	975	slog (L_INFO, _("DNS: client %d connects"), client);
918		976
919	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	977	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
920	pkt [offs++] = CMD_IP_REJ;	978	pkt [offs++] = CMD_IP_REJ;
921		979
922	if (0 < client && client <= conns.size ())	980	if (0 < client && client <= conns.size ())
…		…
959	int seqno = (*i)->seqno;	1017	int seqno = (*i)->seqno;
960	u8 data[MAXSIZE], *datap = data;	1018	u8 data[MAXSIZE], *datap = data;
961		1019
962	if ((*i)->retry)	1020	if ((*i)->retry)
963	{	1021	{
964	dns->send_interval *= 1.001;	1022	dns->send_interval *= 1.01;
965	if (dns->send_interval > MAX_SEND_INTERVAL)	1023	if (dns->send_interval > MAX_SEND_INTERVAL)
966	dns->send_interval = MAX_SEND_INTERVAL;	1024	dns->send_interval = MAX_SEND_INTERVAL;
967	}	1025	}
968	else	1026	else
969	{	1027	{
970	#if 1	1028	#if 0
971	dns->send_interval *= 0.9999;	1029	dns->send_interval *= 0.999;
972	#endif	1030	#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	1031	// the latency surely puts an upper bound on
977	// the minimum send interval	1032	// the minimum send interval
978	double latency = NOW - (*i)->sent;	1033	double latency = NOW - (*i)->sent;
979		1034
		1035	if (latency < dns->min_latency)
		1036	dns->min_latency = latency;
		1037
980	if (dns->send_interval > latency)	1038	if (dns->send_interval > dns->min_latency * LATENCY_FACTOR)
981	dns->send_interval = latency;	1039	dns->send_interval = dns->min_latency * LATENCY_FACTOR;
		1040
		1041	if (dns->send_interval < MIN_SEND_INTERVAL)
		1042	dns->send_interval = MIN_SEND_INTERVAL;
982	}	1043	}
983		1044
984	delete *i;	1045	delete *i;
985	dns_sndpq.erase (i);	1046	dns_sndpq.erase (i);
986		1047
…		…
1036		1097
1037	if (ip [0] == CMD_IP_1	1098	if (ip [0] == CMD_IP_1
1038	&& ip [1] == CMD_IP_2	1099	&& ip [1] == CMD_IP_2
1039	&& ip [2] == CMD_IP_3)	1100	&& ip [2] == CMD_IP_3)
1040	{	1101	{
1041	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);	1102	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1042		1103
1043	if (ip [3] == CMD_IP_RST)	1104	if (ip [3] == CMD_IP_RST)
1044	{	1105	{
1045	slog (L_DEBUG, _("got tunnel RST request"));	1106	slog (L_DEBUG, _("DNS: got tunnel RST request"));
1046		1107
1047	delete dns; c->dns = 0;	1108	delete dns; c->dns = 0;
1048		1109
1049	return;	1110	return;
1050	}	1111	}
1051	else if (ip [3] == CMD_IP_SYN)	1112	else if (ip [3] == CMD_IP_SYN)
1052	{	1113	{
1053	slog (L_DEBUG, _("got tunnel SYN reply, server likes us."));	1114	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1054	dns->established = true;	1115	dns->established = true;
1055	}	1116	}
1056	else if (ip [3] == CMD_IP_REJ)	1117	else if (ip [3] == CMD_IP_REJ)
1057	{	1118	{
1058	slog (L_DEBUG, _("got tunnel REJ reply, server does not like us, aborting."));	1119	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
1059	abort ();	1120	abort ();
1060	}	1121	}
1061	else	1122	else
1062	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);	1123	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1063	}	1124	}
1064	else	1125	else
1065	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),	1126	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1066	ip [0], ip [1], ip [2], ip [3]);	1127	ip [0], ip [1], ip [2], ip [3]);
1067		1128
1068	return;	1129	return;
1069	}	1130	}
1070		1131
1071	int client, rseqno;	1132	int client, rseqno;
1072	decode_header (qname, client, rseqno);	1133	decode_header (qname, client, rseqno);
1073		1134
1074	if (client != THISNODE->id)	1135	if (client != THISNODE->id)
1075	{	1136	{
1076	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));	1137	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1077	datap = 0;	1138	datap = 0;
1078	}	1139	}
1079	else if (rseqno != seqno)	1140	else if (rseqno != seqno)
1080	{	1141	{
1081	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));	1142	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
1082	datap = 0;	1143	datap = 0;
1083	}	1144	}
1084	}	1145	}
1085	}	1146	}
1086		1147
…		…
1103		1164
1104	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);	1165	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1105		1166
1106	if (pkt->len > 0)	1167	if (pkt->len > 0)
1107	{	1168	{
1108	if (THISNODE->dns_port)	1169	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1170	dnsv4_client (*pkt);
		1171	else
1109	{	1172	{
1110	dnsv4_server (*pkt);	1173	dnsv4_server (*pkt);
1111	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);	1174	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1112	}	1175	}
1113	else
1114	dnsv4_client (*pkt);
1115		1176
1116	delete pkt;	1177	delete pkt;
1117	}	1178	}
1118	}	1179	}
1119	}	1180	}
1120		1181
1121	bool	1182	bool
1122	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1183	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1123	{	1184	{
		1185	int client = ntohl (si.host);
		1186
		1187	assert (0 < client && client <= conns.size ());
		1188
		1189	connection *c = conns [client - 1];
		1190
1124	if (!dns)	1191	if (!c->dns)
1125	dns = new dns_connection (this);	1192	c->dns = new dns_connection (c);
1126		1193
1127	if (!dns->snddq.put (pkt))	1194	if (c->dns->snddq.put (pkt))
1128	return false;
1129
1130	dns->tw.trigger ();	1195	c->dns->tw.trigger ();
1131		1196
		1197	// always return true even if the buffer overflows
1132	return true;	1198	return true;
1133	}	1199	}
1134		1200
1135	void	1201	void
1136	connection::dnsv4_reset_connection ()	1202	connection::dnsv4_reset_connection ()
…		…
1162	if (!send)	1228	if (!send)
1163	{	1229	{
1164	send = r;	1230	send = r;
1165		1231
1166	r->retry++;	1232	r->retry++;
1167	r->timeout = NOW + r->retry;	1233	r->timeout = NOW + (r->retry * min_latency * TIMEOUT_FACTOR);
		1234
		1235	// the following code changes the query section a bit, forcing
		1236	// the forwarder to generate a new request
		1237	if (r->stdhdr)
		1238	{
		1239	//printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
		1240	//encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
		1241	}
1168	}	1242	}
1169	}	1243	}
1170	else	1244	else
1171	NEXT (r->timeout);	1245	NEXT (r->timeout);
1172	}	1246	}
1173		1247
1174	if (last_sent + send_interval <= NOW)
1175	{
1176	if (!send)	1248	if (!send)
		1249	{
		1250	// generate a new packet, if wise
		1251
		1252	if (!established)
1177	{	1253	{
1178	// generate a new packet, if wise
1179
1180	if (!established)
1181	{
1182	if (vpn->dns_sndpq.empty ())	1254	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	{	1255	{
1192	send = new dns_snd (this);	1256	send = new dns_snd (this);
		1257
		1258	cfg.reset (THISNODE->id);
		1259	send->gen_syn_req ();
		1260	}
		1261	}
		1262	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
		1263	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1264	{
		1265	if (last_sent + send_interval <= NOW)
		1266	{
		1267	//printf ("sending data request etc.\n"); //D
		1268	if (!snddq.empty () \|\| last_received + 1. > NOW)
		1269	{
		1270	poll_interval = send_interval;
		1271	NEXT (NOW + send_interval);
		1272	}
		1273
		1274	send = new dns_snd (this);
1193	send->gen_stream_req (sndseq, snddq);	1275	send->gen_stream_req (sndseq, snddq);
		1276	send->timeout = NOW + min_latency * TIMEOUT_FACTOR;
1194		1277
1195	sndseq = (sndseq + 1) & SEQNO_MASK;	1278	sndseq = (sndseq + 1) & SEQNO_MASK;
1196	}	1279	}
1197		1280	else
1198	if (send)	1281	NEXT (last_sent + send_interval);
1199	vpn->dns_sndpq.push_back (send);
1200	}	1282	}
1201		1283
1202	if (send)	1284	if (send)
1203	{	1285	vpn->dns_sndpq.push_back (send);
		1286	}
		1287
		1288	if (send)
		1289	{
1204	last_sent = NOW;	1290	last_sent = NOW;
1205	sendto (vpn->dnsv4_fd,	1291	sendto (vpn->dnsv4_fd,
1206	send->pkt->at (0), send->pkt->len, 0,	1292	send->pkt->at (0), send->pkt->len, 0,
1207	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1293	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1208	}
1209	}	1294	}
1210	else
1211	NEXT (last_sent + send_interval);
1212		1295
1213	slog (L_NOISE, "pi %f si %f N %f (%d:%d)",	1296	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1214	poll_interval, send_interval, next - NOW,	1297	poll_interval, send_interval, next - NOW,
1215	vpn->dns_sndpq.size (), snddq.size ());	1298	vpn->dns_sndpq.size (), snddq.size (),
		1299	rcvpq.size ());
1216		1300
1217	// TODO: no idea when this happens, but when next < NOW, we have a problem	1301	// TODO: no idea when this happens, but when next < NOW, we have a problem
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

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC vs. Revision 1.35 by pcg, Wed Mar 16 14:56:32 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 1.35 by pcg, Wed Mar 16 14:56:32 2005 UTC