[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 1.30 by pcg, Mon Mar 14 17:40:01 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 INITIAL_TIMEOUT 1. // retry timeouts	52	#define INITIAL_TIMEOUT 0.1 // retry timeouts
53	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn	53	#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn
54		54
55	#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests	55	#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
56	#define MAX_SEND_INTERVAL 0.5 // optimistic?	56	#define MAX_SEND_INTERVAL 2. // optimistic?
57		57
		58	#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
58	#define MAX_OUTSTANDING 40 // max. outstanding requests	59	#define MAX_OUTSTANDING 2 // max. outstanding requests
59	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING	60	#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	61	#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
61		62
62	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	63	#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	64	// 240 leaves about 4 bytes of server reply data
64	// every two request bytes less give room for one reply byte	65	// every two request bytes less give room for one reply byte
65		66
66	#define SEQNO_MASK 0xffff	67	#define SEQNO_MASK 0x3fff
67	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	68	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
68		69
69	#define MAX_LBL_SIZE 63	70	#define MAX_LBL_SIZE 63
70	#define MAX_PKT_SIZE 512	71	#define MAX_PKT_SIZE 512
71		72
…		…
264	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	265	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
265		266
266	/////////////////////////////////////////////////////////////////////////////	267	/////////////////////////////////////////////////////////////////////////////
267		268
268	#define HDRSIZE 6	269	#define HDRSIZE 6
269		270
270	inline void encode_header (char *data, int clientid, int seqno)	271	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
271	{	272	{
272	u8 hdr[3] = { clientid, seqno >> 8, seqno };	273	seqno &= SEQNO_MASK;
		274
		275	u8 hdr[3] = {
		276	clientid,
		277	(seqno >> 8) \| (retry << 6),
		278	seqno,
		279	};
273		280
274	assert (clientid < 256);	281	assert (clientid < 256);
275		282
276	cdc26.encode (data, hdr, 3);	283	cdc26.encode (data, hdr, 3);
277	}	284	}
…		…
281	u8 hdr[3];	288	u8 hdr[3];
282		289
283	cdc26.decode (hdr, data, HDRSIZE);	290	cdc26.decode (hdr, data, HDRSIZE);
284		291
285	clientid = hdr[0];	292	clientid = hdr[0];
286	seqno = (hdr[1] << 8) \| hdr[2];	293	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
287	}	294	}
288		295
289	/////////////////////////////////////////////////////////////////////////////	296	/////////////////////////////////////////////////////////////////////////////
290		297
291	struct byte_stream	298	struct byte_stream
…		…
320	}	327	}
321		328
322	void byte_stream::remove (int count)	329	void byte_stream::remove (int count)
323	{	330	{
324	if (count > fill)	331	if (count > fill)
325	abort ();	332	assert (count <= fill);
326		333
327	memmove (data, data + count, fill -= count);	334	memmove (data, data + count, fill -= count);
328	}	335	}
329		336
330	bool byte_stream::put (u8 *data, unsigned int datalen)	337	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
350	return true;	357	return true;
351	}	358	}
352		359
353	vpn_packet *byte_stream::get ()	360	vpn_packet *byte_stream::get ()
354	{	361	{
		362	unsigned int len;
		363
		364	for (;;)
		365	{
355	unsigned int len = (data [0] << 8) \| data [1];	366	len = (data [0] << 8) \| data [1];
356		367
357	if (len > MAXSIZE && fill >= 2)	368	if (len <= MAXSIZE \|\| fill < 2)
358	abort (); // TODO handle this gracefully, connection reset	369	break;
359		370
		371	// TODO: handle this better than skipping, e.g. by reset
		372	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		373	remove (1);
		374	}
		375
360	if (fill < len + 2)	376	if (fill < len + 2)
361	return 0;	377	return 0;
362		378
363	vpn_packet *pkt = new vpn_packet;	379	vpn_packet *pkt = new vpn_packet;
364		380
…		…
393	struct dns_cfg	409	struct dns_cfg
394	{	410	{
395	static int next_uid;	411	static int next_uid;
396		412
397	u8 id1, id2, id3, id4;	413	u8 id1, id2, id3, id4;
		414
398	u8 version;	415	u8 version;
		416	u8 flags;
399	u8 rrtype;	417	u8 rrtype;
400	u8 flags;
401	u8 def_ttl;	418	u8 def_ttl;
402	u8 rcv_cdc;	419
403	u8 snd_cdc;
404	u16 max_size;
405	u16 client;	420	u16 client;
406	u16 uid; // to make request unique	421	u16 uid; // to make request unique
407		422
408	u8 reserved[8];	423	u16 max_size;
		424	u8 seq_cdc;
		425	u8 req_cdc;
		426
		427	u8 rep_cdc;
		428	u8 delay; // time in 0.01s units that the server may delay replying packets
		429	u8 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++;
		457	delay = 0;
433		458
434	memset (reserved, 0, 8);	459	r3 = r4 = 0;
		460	r4 = r5 = r6 = r7 = 0;
435	}	461	}
436		462
437	bool dns_cfg::valid ()	463	bool dns_cfg::valid ()
438	{	464	{
439	return id1 == 'G'	465	return id1 == 'G'
440	&& id2 == 'V'	466	&& id2 == 'V'
441	&& id3 == 'P'	467	&& id3 == 'P'
442	&& id4 == 'E'	468	&& id4 == 'E'
		469	&& seq_cdc == 26
		470	&& req_cdc == 62
		471	&& rep_cdc == 0
443	&& version == 1	472	&& version == 1;
444	&& flags == 0
445	&& rcv_cdc == 0
446	&& snd_cdc == 62
447	&& max_size == ntohs (MAX_PKT_SIZE);
448	}	473	}
449		474
450	struct dns_packet : net_packet	475	struct dns_packet : net_packet
451	{	476	{
452	u16 id;	477	u16 id;
453	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	478	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
454	u16 qdcount, ancount, nscount, arcount;	479	u16 qdcount, ancount, nscount, arcount;
455		480
456	u8 data[MAXSIZE - 6 * 2];	481	u8 data [MAXSIZE - 6 * 2];
457		482
458	int decode_label (char *data, int size, int &offs);	483	int decode_label (char *data, int size, int &offs);
459	};	484	};
460		485
461	int dns_packet::decode_label (char *data, int size, int &offs)	486	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
492	return data - orig;	517	return data - orig;
493	}	518	}
494		519
495	/////////////////////////////////////////////////////////////////////////////	520	/////////////////////////////////////////////////////////////////////////////
496		521
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	522	static u16 dns_id = 0; // TODO: should be per-vpn
513		523
514	static u16 next_id ()	524	static u16 next_id ()
515	{	525	{
		526	if (!dns_id)
		527	dns_id = time (0);
		528
516	// the simplest lsfr with periodicity 65535 i could find	529	// the simplest lsfr with periodicity 65535 i could find
517	dns_id = (dns_id << 1)	530	dns_id = (dns_id << 1)
518	\| (((dns_id >> 1)	531	\| (((dns_id >> 1)
519	^ (dns_id >> 2)	532	^ (dns_id >> 2)
520	^ (dns_id >> 4)	533	^ (dns_id >> 4)
521	^ (dns_id >> 15)) & 1);	534	^ (dns_id >> 15)) & 1);
522		535
523	return dns_id;	536	return dns_id;
524	}	537	}
525		538
		539	struct dns_rcv;
		540	struct dns_snd;
		541
		542	struct dns_connection
		543	{
		544	connection *c;
		545	struct vpn *vpn;
		546
		547	dns_cfg cfg;
		548
		549	bool established;
		550
		551	tstamp last_received;
		552	tstamp last_sent;
		553	double min_latency;
		554	double poll_interval, send_interval;
		555
		556	vector<dns_rcv *> rcvpq;
		557
		558	byte_stream rcvdq; int rcvseq;
		559	byte_stream snddq; int sndseq;
		560
		561	void time_cb (time_watcher &w); time_watcher tw;
		562	void receive_rep (dns_rcv *r);
		563
		564	dns_connection (connection *c);
		565	~dns_connection ();
		566	};
		567
		568	struct dns_snd
		569	{
		570	dns_packet *pkt;
		571	tstamp timeout, sent;
		572	int retry;
		573	struct dns_connection *dns;
		574	int seqno;
		575	bool stdhdr;
		576
		577	void gen_stream_req (int seqno, byte_stream &stream);
		578	void gen_syn_req ();
		579
		580	dns_snd (dns_connection *dns);
		581	~dns_snd ();
		582	};
		583
526	dns_snd::dns_snd (dns_connection *dns)	584	dns_snd::dns_snd (dns_connection *dns)
527	: dns (dns)	585	: dns (dns)
528	{	586	{
529	timeout = 0;	587	timeout = 0;
530	retry = 0;	588	retry = 0;
531	seqno = 0;	589	seqno = 0;
532	sent = NOW;	590	sent = NOW;
		591	stdhdr = false;
533		592
534	pkt = new dns_packet;	593	pkt = new dns_packet;
535		594
536	pkt->id = next_id ();	595	pkt->id = next_id ();
537	}	596	}
…		…
564	}	623	}
565	}	624	}
566		625
567	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)	626	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
568	{	627	{
		628	stdhdr = true;
569	this->seqno = seqno;	629	this->seqno = seqno;
570		630
571	timeout = NOW + INITIAL_TIMEOUT;	631	timeout = NOW + INITIAL_TIMEOUT;
572		632
573	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	633	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
574	pkt->qdcount = htons (1);	634	pkt->qdcount = htons (1);
575		635
576	int offs = 6*2;	636	int offs = 6*2;
577	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	637	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,	638	// 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	639	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
580		640
581	char enc[256], *encp = enc;	641	char enc[256], *encp = enc;
582	encode_header (enc, THISNODE->id, seqno);	642	encode_header (enc, THISNODE->id, seqno);
…		…
600	encp += lbllen;	660	encp += lbllen;
601		661
602	enclen -= lbllen;	662	enclen -= lbllen;
603	}	663	}
604		664
605	append_domain (*pkt, offs, THISNODE->domain);	665	append_domain (*pkt, offs, dns->c->conf->domain);
606		666
607	(*pkt)[offs++] = 0;	667	(*pkt)[offs++] = 0;
608	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	668	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
609	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	669	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
610		670
611	pkt->len = offs;	671	pkt->len = offs;
612	}	672	}
613		673
614	void dns_snd::gen_syn_req (const dns_cfg &cfg)	674	void dns_snd::gen_syn_req ()
615	{	675	{
616	timeout = NOW + INITIAL_SYN_TIMEOUT;	676	timeout = NOW + INITIAL_SYN_TIMEOUT;
617		677
618	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	678	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
619	pkt->qdcount = htons (1);	679	pkt->qdcount = htons (1);
620		680
621	int offs = 6*2;	681	int offs = 6 * 2;
622		682
623	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));	683	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
624		684
625	assert (elen <= MAX_LBL_SIZE);	685	assert (elen <= MAX_LBL_SIZE);
626		686
627	(*pkt)[offs] = elen;	687	(*pkt)[offs] = elen;
628	offs += elen + 1;	688	offs += elen + 1;
629	append_domain (*pkt, offs, THISNODE->domain);	689	append_domain (*pkt, offs, dns->c->conf->domain);
630		690
631	(*pkt)[offs++] = 0;	691	(*pkt)[offs++] = 0;
632	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;	692	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
633	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	693	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
634		694
…		…
657	delete pkt;	717	delete pkt;
658	}	718	}
659		719
660	/////////////////////////////////////////////////////////////////////////////	720	/////////////////////////////////////////////////////////////////////////////
661		721
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)	722	dns_connection::dns_connection (connection *c)
688	: c (c)	723	: c (c)
689	, rcvdq (MAX_BACKLOG * 2)	724	, rcvdq (MAX_BACKLOG * 2)
690	, snddq (MAX_BACKLOG * 2)	725	, snddq (MAX_BACKLOG * 2)
691	, tw (this, &dns_connection::time_cb)	726	, tw (this, &dns_connection::time_cb)
…		…
695	established = false;	730	established = false;
696		731
697	rcvseq = sndseq = 0;	732	rcvseq = sndseq = 0;
698		733
699	last_sent = last_received = 0;	734	last_sent = last_received = 0;
700	poll_interval = MIN_POLL_INTERVAL;	735	poll_interval = 0.5; // starting here
701	send_interval = 0.2; // starting rate	736	send_interval = 0.5; // starting rate
		737	min_latency = INITIAL_TIMEOUT;
702	}	738	}
703		739
704	dns_connection::~dns_connection ()	740	dns_connection::~dns_connection ()
705	{	741	{
706	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	742	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
…		…
718		754
719	poll_interval = send_interval;	755	poll_interval = send_interval;
720	}	756	}
721	else	757	else
722	{	758	{
723	poll_interval *= 1.1;	759	poll_interval *= 1.5;
		760
724	if (poll_interval > MAX_POLL_INTERVAL)	761	if (poll_interval > MAX_POLL_INTERVAL)
725	poll_interval = MAX_POLL_INTERVAL;	762	poll_interval = MAX_POLL_INTERVAL;
726	}	763	}
727		764
728	rcvpq.push_back (r);	765	rcvpq.push_back (r);
…		…
746	}	783	}
747		784
748	rcvseq = (rcvseq + 1) & SEQNO_MASK;	785	rcvseq = (rcvseq + 1) & SEQNO_MASK;
749		786
750	if (!rcvdq.put (r->data, r->datalen))	787	if (!rcvdq.put (r->data, r->datalen))
		788	{
		789	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
751	abort (); // MUST never overflow, can be caused by data corruption, TODO	790	abort (); // MUST never overflow, can be caused by data corruption, TODO
		791	}
752		792
753	while (vpn_packet *pkt = rcvdq.get ())	793	while (vpn_packet *pkt = rcvdq.get ())
754	{	794	{
755	sockinfo si;	795	sockinfo si;
756	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	796	si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4;
757		797
758	vpn->recv_vpn_packet (pkt, si);	798	vpn->recv_vpn_packet (pkt, si);
759		799
760	delete pkt;	800	delete pkt;
761	}	801	}
…		…
775	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	815	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
776		816
777	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))	817	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
778	&& pkt.qdcount == htons (1))	818	&& pkt.qdcount == htons (1))
779	{	819	{
780	char qname[MAXSIZE];	820	char qname [MAXSIZE];
781	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);	821	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
782		822
783	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];	823	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
784	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];	824	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
785		825
786	pkt.qdcount = htons (1);	826	pkt.qdcount = htons (1);
787	pkt.ancount = 0;	827	pkt.ancount = 0;
788	pkt.nscount = 0; // should be self, as other nameservers reply like this	828	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	829	pkt.arcount = 0; // a record for self, as other nameservers reply like this
790		830
791	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	831	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
792		832
793	int dlen = strlen (THISNODE->domain);	833	int dlen = strlen (THISNODE->domain);
794		834
795	if (qclass == RR_CLASS_IN	835	if (qclass == RR_CLASS_IN
796	&& qlen > dlen + 1	836	&& qlen > dlen + 1
797	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	837	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
798	{	838	{
799	// now generate reply	839	// now generate reply
800	pkt.ancount = htons (1); // one answer RR	840	pkt.ancount = htons (1); // one answer RR
801	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	841	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
802		842
…		…
815	if (0 < client && client <= conns.size ())	855	if (0 < client && client <= conns.size ())
816	{	856	{
817	connection *c = conns [client - 1];	857	connection *c = conns [client - 1];
818	dns_connection *dns = c->dns;	858	dns_connection *dns = c->dns;
819	dns_rcv *rcv;	859	dns_rcv *rcv;
		860	bool in_seq;
820		861
821	if (dns)	862	if (dns)
822	{	863	{
823	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )	864	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
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	}
		880
		881	in_seq = dns->rcvseq == seqno;
835		882
836	// new packet, queue	883	// new packet, queue
837	rcv = new dns_rcv (seqno, data, datalen);	884	rcv = new dns_rcv (seqno, data, datalen);
838	dns->receive_rep (rcv);	885	dns->receive_rep (rcv);
839	}	886	}
840		887
		888	{
841	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section	889	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
842		890
843	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;	891	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
844	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type	892	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
845	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	893	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
846	pkt [offs++] = 0; pkt [offs++] = 0;	894	pkt [offs++] = 0; pkt [offs++] = 0;
847	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL	895	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
848		896
849	int rdlen_offs = offs += 2;	897	int rdlen_offs = offs += 2;
850		898
		899	if (dns)
		900	{
851	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;	901	int dlen = ntohs (dns->cfg.max_size) - offs;
		902
852	// bind doesn't compress well, so reduce further by one label length	903	// bind doesn't compress well, so reduce further by one label length
853	dlen -= qlen;	904	dlen -= qlen;
854		905
855	if (dns)	906	// only put data into in-order sequence packets, if
856	{	907	// we receive out-of-order packets we generate empty
		908	// replies
857	while (dlen > 1 && !dns->snddq.empty ())	909	while (dlen > 1 && !dns->snddq.empty () && in_seq)
858	{	910	{
859	int txtlen = dlen <= 255 ? dlen - 1 : 255;	911	int txtlen = dlen <= 255 ? dlen - 1 : 255;
860		912
861	if (txtlen > dns->snddq.size ())	913	if (txtlen > dns->snddq.size ())
862	txtlen = dns->snddq.size ();	914	txtlen = dns->snddq.size ();
863		915
864	pkt[offs++] = txtlen;	916	pkt[offs++] = txtlen;
865	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);	917	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
866	offs += txtlen;	918	offs += txtlen;
867	dns->snddq.remove (txtlen);	919	dns->snddq.remove (txtlen);
868		920
869	dlen -= txtlen + 1;	921	dlen -= txtlen + 1;
870	}	922	}
871		923
872	// avoid empty TXT rdata	924	// avoid empty TXT rdata
873	if (offs == rdlen_offs)	925	if (offs == rdlen_offs)
874	pkt[offs++] = 0;	926	pkt[offs++] = 0;
875		927
876	slog (L_NOISE, "snddq %d", dns->snddq.size ());	928	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
877	}	929	}
878	else	930	else
879	{	931	{
880	// send RST	932	// send RST
881	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	933	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
882	pkt [offs++] = CMD_IP_RST;	934	pkt [offs++] = CMD_IP_RST;
883	}	935	}
884		936
885	int rdlen = offs - rdlen_offs;	937	int rdlen = offs - rdlen_offs;
886		938
887	pkt [rdlen_offs - 2] = rdlen >> 8;	939	pkt [rdlen_offs - 2] = rdlen >> 8;
888	pkt [rdlen_offs - 1] = rdlen;	940	pkt [rdlen_offs - 1] = rdlen;
889		941
890	if (dns)	942	if (dns)
891	{	943	{
892	// now update dns_rcv copy	944	// now update dns_rcv copy
893	rcv->pkt->len = offs;	945	rcv->pkt->len = offs;
894	memcpy (rcv->pkt->at (0), pkt.at (0), offs);	946	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
895	}	947	}
		948	}
896		949
897	duplicate_request: ;	950	duplicate_request: ;
898	}	951	}
899	else	952	else
900	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	953	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
…		…
912	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class	965	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
913	pkt [offs++] = 0; pkt [offs++] = 0;	966	pkt [offs++] = 0; pkt [offs++] = 0;
914	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL	967	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
915	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength	968	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
916		969
917	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);	970	slog (L_INFO, _("DNS: client %d connects"), client);
918		971
919	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;	972	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
920	pkt [offs++] = CMD_IP_REJ;	973	pkt [offs++] = CMD_IP_REJ;
921		974
922	if (0 < client && client <= conns.size ())	975	if (0 < client && client <= conns.size ())
…		…
959	int seqno = (*i)->seqno;	1012	int seqno = (*i)->seqno;
960	u8 data[MAXSIZE], *datap = data;	1013	u8 data[MAXSIZE], *datap = data;
961		1014
962	if ((*i)->retry)	1015	if ((*i)->retry)
963	{	1016	{
964	dns->send_interval *= 1.001;	1017	dns->send_interval *= 1.01;
965	if (dns->send_interval > MAX_SEND_INTERVAL)	1018	if (dns->send_interval > MAX_SEND_INTERVAL)
966	dns->send_interval = MAX_SEND_INTERVAL;	1019	dns->send_interval = MAX_SEND_INTERVAL;
967	}	1020	}
968	else	1021	else
969	{	1022	{
970	#if 1	1023	#if 0
971	dns->send_interval *= 0.9999;	1024	dns->send_interval *= 0.999;
972	#endif	1025	#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	1026	// the latency surely puts an upper bound on
977	// the minimum send interval	1027	// the minimum send interval
978	double latency = NOW - (*i)->sent;	1028	double latency = NOW - (*i)->sent;
979		1029
		1030	if (latency < dns->min_latency)
		1031	dns->min_latency = latency;
		1032
980	if (dns->send_interval > latency)	1033	if (dns->send_interval > dns->min_latency * LATENCY_FACTOR)
981	dns->send_interval = latency;	1034	dns->send_interval = dns->min_latency * LATENCY_FACTOR;
		1035
		1036	if (dns->send_interval < MIN_SEND_INTERVAL)
		1037	dns->send_interval = MIN_SEND_INTERVAL;
982	}	1038	}
983		1039
984	delete *i;	1040	delete *i;
985	dns_sndpq.erase (i);	1041	dns_sndpq.erase (i);
986		1042
…		…
1036		1092
1037	if (ip [0] == CMD_IP_1	1093	if (ip [0] == CMD_IP_1
1038	&& ip [1] == CMD_IP_2	1094	&& ip [1] == CMD_IP_2
1039	&& ip [2] == CMD_IP_3)	1095	&& ip [2] == CMD_IP_3)
1040	{	1096	{
1041	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);	1097	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
1042		1098
1043	if (ip [3] == CMD_IP_RST)	1099	if (ip [3] == CMD_IP_RST)
1044	{	1100	{
1045	slog (L_DEBUG, _("got tunnel RST request"));	1101	slog (L_DEBUG, _("DNS: got tunnel RST request"));
1046		1102
1047	delete dns; c->dns = 0;	1103	delete dns; c->dns = 0;
1048		1104
1049	return;	1105	return;
1050	}	1106	}
1051	else if (ip [3] == CMD_IP_SYN)	1107	else if (ip [3] == CMD_IP_SYN)
1052	{	1108	{
1053	slog (L_DEBUG, _("got tunnel SYN reply, server likes us."));	1109	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
1054	dns->established = true;	1110	dns->established = true;
1055	}	1111	}
1056	else if (ip [3] == CMD_IP_REJ)	1112	else if (ip [3] == CMD_IP_REJ)
1057	{	1113	{
1058	slog (L_DEBUG, _("got tunnel REJ reply, server does not like us, aborting."));	1114	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
1059	abort ();	1115	abort ();
1060	}	1116	}
1061	else	1117	else
1062	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);	1118	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
1063	}	1119	}
1064	else	1120	else
1065	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),	1121	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
1066	ip [0], ip [1], ip [2], ip [3]);	1122	ip [0], ip [1], ip [2], ip [3]);
1067		1123
1068	return;	1124	return;
1069	}	1125	}
1070		1126
1071	int client, rseqno;	1127	int client, rseqno;
1072	decode_header (qname, client, rseqno);	1128	decode_header (qname, client, rseqno);
1073		1129
1074	if (client != THISNODE->id)	1130	if (client != THISNODE->id)
1075	{	1131	{
1076	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));	1132	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
1077	datap = 0;	1133	datap = 0;
1078	}	1134	}
1079	else if (rseqno != seqno)	1135	else if (rseqno != seqno)
1080	{	1136	{
1081	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));	1137	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
1082	datap = 0;	1138	datap = 0;
1083	}	1139	}
1084	}	1140	}
1085	}	1141	}
1086		1142
…		…
1103		1159
1104	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);	1160	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1105		1161
1106	if (pkt->len > 0)	1162	if (pkt->len > 0)
1107	{	1163	{
1108	if (THISNODE->dns_port)	1164	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1165	dnsv4_client (*pkt);
		1166	else
1109	{	1167	{
1110	dnsv4_server (*pkt);	1168	dnsv4_server (*pkt);
1111	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);	1169	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1112	}	1170	}
1113	else
1114	dnsv4_client (*pkt);
1115		1171
1116	delete pkt;	1172	delete pkt;
1117	}	1173	}
1118	}	1174	}
1119	}	1175	}
1120		1176
1121	bool	1177	bool
1122	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1178	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1123	{	1179	{
		1180	int client = ntohs (si.port);
		1181
		1182	assert (0 < client && client <= conns.size ());
		1183
		1184	connection *c = conns [client - 1];
		1185
1124	if (!dns)	1186	if (!c->dns)
1125	dns = new dns_connection (this);	1187	c->dns = new dns_connection (c);
1126		1188
1127	if (!dns->snddq.put (pkt))	1189	if (!c->dns->snddq.put (pkt))
1128	return false;	1190	return false;
1129		1191
1130	dns->tw.trigger ();	1192	c->dns->tw.trigger ();
1131		1193
1132	return true;	1194	return true;
1133	}	1195	}
1134		1196
1135	void	1197	void
…		…
1162	if (!send)	1224	if (!send)
1163	{	1225	{
1164	send = r;	1226	send = r;
1165		1227
1166	r->retry++;	1228	r->retry++;
1167	r->timeout = NOW + r->retry;	1229	r->timeout = NOW + (r->retry * min_latency * 8.);
		1230
		1231	// the following code changes the query section a bit, forcing
		1232	// the forwarder to generate a new request
		1233	if (r->stdhdr)
		1234	{
		1235	//printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
		1236	//encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
		1237	}
1168	}	1238	}
1169	}	1239	}
1170	else	1240	else
1171	NEXT (r->timeout);	1241	NEXT (r->timeout);
1172	}	1242	}
1173		1243
1174	if (last_sent + send_interval <= NOW)
1175	{
1176	if (!send)	1244	if (!send)
		1245	{
		1246	// generate a new packet, if wise
		1247
		1248	if (!established)
1177	{	1249	{
1178	// generate a new packet, if wise
1179
1180	if (!established)
1181	{
1182	if (vpn->dns_sndpq.empty ())	1250	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	{	1251	{
1192	send = new dns_snd (this);	1252	send = new dns_snd (this);
		1253
		1254	cfg.reset (THISNODE->id);
		1255	send->gen_syn_req ();
		1256	}
		1257	}
		1258	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
		1259	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1260	{
		1261	if (last_sent + send_interval <= NOW)
		1262	{
		1263	//printf ("sending data request etc.\n"); //D
		1264	if (!snddq.empty () \|\| last_received + 1. > NOW)
		1265	{
		1266	poll_interval = send_interval;
		1267	NEXT (NOW + send_interval);
		1268	}
		1269
		1270	send = new dns_snd (this);
1193	send->gen_stream_req (sndseq, snddq);	1271	send->gen_stream_req (sndseq, snddq);
		1272	send->timeout = NOW + min_latency * 8.;
1194		1273
1195	sndseq = (sndseq + 1) & SEQNO_MASK;	1274	sndseq = (sndseq + 1) & SEQNO_MASK;
1196	}	1275	}
1197		1276	else
1198	if (send)	1277	NEXT (last_sent + send_interval);
1199	vpn->dns_sndpq.push_back (send);
1200	}	1278	}
1201		1279
1202	if (send)	1280	if (send)
1203	{	1281	vpn->dns_sndpq.push_back (send);
		1282	}
		1283
		1284	if (send)
		1285	{
1204	last_sent = NOW;	1286	last_sent = NOW;
1205	sendto (vpn->dnsv4_fd,	1287	sendto (vpn->dnsv4_fd,
1206	send->pkt->at (0), send->pkt->len, 0,	1288	send->pkt->at (0), send->pkt->len, 0,
1207	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1289	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1208	}
1209	}	1290	}
1210	else
1211	NEXT (last_sent + send_interval);
1212		1291
1213	slog (L_NOISE, "pi %f si %f N %f (%d:%d)",	1292	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1214	poll_interval, send_interval, next - NOW,	1293	poll_interval, send_interval, next - NOW,
1215	vpn->dns_sndpq.size (), snddq.size ());	1294	vpn->dns_sndpq.size (), snddq.size (),
		1295	rcvpq.size ());
1216		1296
1217	// TODO: no idea when this happens, but when next < NOW, we have a problem	1297	// TODO: no idea when this happens, but when next < NOW, we have a problem
1218	if (next < NOW + 0.0001)	1298	if (next < NOW + 0.001)
1219	next = NOW + 0.1;	1299	next = NOW + 0.1;
1220		1300
1221	w.start (next);	1301	w.start (next);
1222	}	1302	}
1223		1303

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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 1.30 by pcg, Mon Mar 14 17:40:01 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 1.30 by pcg, Mon Mar 14 17:40:01 2005 UTC