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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs.
Revision 1.46 by pcg, Thu Dec 6 00:35:29 2007 UTC

…		…
14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15	GNU General Public License for more details.	15	GNU General Public License for more details.
16		16
17	You should have received a copy of the GNU General Public License	17	You should have received a copy of the GNU General Public License
18	along with gvpe; if not, write to the Free Software	18	along with gvpe; if not, write to the Free Software
19	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA	19	Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20	*/	20	*/
		21
		22	// TODO: EDNS0 option to increase dns mtu?
		23	// TODO: re-write dns packet parsing/creation using a safe mem-buffer
		24	// to ensure no buffer overflows or similar problems.
21		25
22	#include "config.h"	26	#include "config.h"
23		27
24	#if ENABLE_DNS	28	#if ENABLE_DNS
25		29
26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.	30	// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27	// it's a hack, use only in emergency situations please.	31	// it's a hack, use only in emergency situations please.
28		32
29	#include <cstring>	33	#include <cstring>
		34	#include <cassert>
30		35
31	#include <sys/types.h>	36	#include <sys/types.h>
32	#include <sys/socket.h>	37	#include <sys/socket.h>
33	#include <sys/wait.h>	38	#include <sys/wait.h>
34	#include <sys/uio.h>	39	#include <sys/uio.h>
…		…
37	#include <unistd.h>	42	#include <unistd.h>
38	#include <fcntl.h>	43	#include <fcntl.h>
39		44
40	#include <map>	45	#include <map>
41		46
		47	#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */
42	#include <gmp.h>	48	#include <gmp.h>
43		49
44	#include "netcompat.h"	50	#include "netcompat.h"
45		51
46	#include "vpn.h"	52	#include "vpn.h"
47		53
48	#define MIN_RETRY 1.	54	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
49	#define MAX_RETRY 6.	55	#define ACTIVITY_INTERVAL 5.
50		56
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	57	#define INITIAL_TIMEOUT 0.1 // retry timeouts
		58	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
		59
		60	#define MAX_SEND_INTERVAL 2. // optimistic?
		61
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	62	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
53	#define MAX_RATE 100 // requests/s
54	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	63	#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55		64
56	#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
57	// 240 leaves about 4 bytes of server reply data	66	// 240 leaves about 4 bytes of server reply data
58	// every two request byte sless give room for one reply byte	67	// every request byte less give room for two reply bytes
59		68
60	#define SEQNO_MASK 0xffff	69	#define SEQNO_MASK 0x3fff
61	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	70	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
62		71
63	#define MAX_LBL_SIZE 63	72	#define MAX_LBL_SIZE 63
64	#define MAX_PKT_SIZE 512	73	#define MAX_PKT_SIZE 512
65		74
		75	#define RR_TYPE_A 1
		76	#define RR_TYPE_NULL 10
66	#define RR_TYPE_TXT 16	77	#define RR_TYPE_TXT 16
67	#define RR_TYPE_ANY 255	78	#define RR_TYPE_ANY 255
		79
68	#define RR_CLASS_IN 1	80	#define RR_CLASS_IN 1
		81
		82	#define CMD_IP_1 207
		83	#define CMD_IP_2 46
		84	#define CMD_IP_3 236
		85	#define CMD_IP_RST 29
		86	#define CMD_IP_SYN 113
		87	#define CMD_IP_REJ 32
69		88
70	// works for cmaps up to 255 (not 256!)	89	// works for cmaps up to 255 (not 256!)
71	struct charmap	90	struct charmap
72	{	91	{
73	enum { INVALID = (u8)255 };	92	enum { INVALID = (u8)255 };
…		…
153	return dec_len [len];	172	return dec_len [len];
154	}	173	}
155		174
156	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	175	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
157	{	176	{
158	if (!len)	177	if (!len \|\| len > MAX_DEC_LEN)
159	return 0;	178	return 0;
160		179
161	int elen = encode_len (len);	180	int elen = encode_len (len);
162		181
163	mp_limb_t m [MAX_LIMBS];	182	mp_limb_t m [MAX_LIMBS];
…		…
182	return elen;	201	return elen;
183	}	202	}
184		203
185	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	204	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
186	{	205	{
187	if (!len)	206	if (!len \|\| len > MAX_ENC_LEN)
188	return 0;	207	return 0;
189		208
190	u8 src_ [MAX_ENC_LEN];	209	u8 src_ [MAX_ENC_LEN];
191	unsigned int elen = 0;	210	unsigned int elen = 0;
192		211
…		…
239	}	258	}
240	abort ();	259	abort ();
241	}	260	}
242	#endif	261	#endif
243		262
244	// the following sequence has been crafted to	263	//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
245	// a) look somewhat random
246	// b) the even (and odd) indices never share the same character as upper/lowercase
247	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)
248	// the other sequences are obviously derived
249	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	264	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
250	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	265	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	266	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
252	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	267	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
253		268
254	/////////////////////////////////////////////////////////////////////////////	269	/////////////////////////////////////////////////////////////////////////////
255		270
256	#define HDRSIZE 6	271	#define HDRSIZE 6
257		272
258	inline void encode_header (char *data, int clientid, int seqno)	273	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
259	{	274	{
260	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	};
261		282
262	assert (clientid < 256);	283	assert (clientid < 256);
263		284
264	cdc26.encode (data, hdr, 3);	285	cdc26.encode (data, hdr, 3);
265	}	286	}
…		…
269	u8 hdr[3];	290	u8 hdr[3];
270		291
271	cdc26.decode (hdr, data, HDRSIZE);	292	cdc26.decode (hdr, data, HDRSIZE);
272		293
273	clientid = hdr[0];	294	clientid = hdr[0];
274	seqno = (hdr[1] << 8) \| hdr[2];	295	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
275	}	296	}
276		297
277	/////////////////////////////////////////////////////////////////////////////	298	/////////////////////////////////////////////////////////////////////////////
278		299
279	struct byte_stream	300	struct byte_stream
…		…
308	}	329	}
309		330
310	void byte_stream::remove (int count)	331	void byte_stream::remove (int count)
311	{	332	{
312	if (count > fill)	333	if (count > fill)
313	abort ();	334	assert (count <= fill);
314		335
315	memmove (data, data + count, fill -= count);	336	memmove (data, data + count, fill -= count);
316	}	337	}
317		338
318	bool byte_stream::put (u8 *data, unsigned int datalen)	339	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
331	return false;	352	return false;
332		353
333	data [fill++] = pkt->len >> 8;	354	data [fill++] = pkt->len >> 8;
334	data [fill++] = pkt->len;	355	data [fill++] = pkt->len;
335		356
336	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	357	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
337		358
338	return true;	359	return true;
339	}	360	}
340		361
341	vpn_packet *byte_stream::get ()	362	vpn_packet *byte_stream::get ()
342	{	363	{
		364	unsigned int len;
		365
		366	for (;;)
		367	{
343	int len = (data [0] << 8) \| data [1];	368	len = (data [0] << 8) \| data [1];
344		369
345	if (len > MAXSIZE && fill >= 2)	370	if (len <= MAXSIZE \|\| fill < 2)
346	abort (); // TODO handle this gracefully, connection reset	371	break;
347		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
348	if (fill < len + 2)	378	if (fill < len + 2)
349	return 0;	379	return 0;
350		380
351	vpn_packet *pkt = new vpn_packet;	381	vpn_packet *pkt = new vpn_packet;
352		382
353	pkt->len = len;	383	pkt->len = len;
354	memcpy (&((*pkt)[0]), data + 2, len);	384	memcpy (pkt->at (0), data + 2, len);
355	remove (len + 2);	385	remove (len + 2);
356		386
357	return pkt;	387	return pkt;
358	}	388	}
359		389
…		…
376	#define FLAG_RCODE_REFUSED ( 5 << 0)	406	#define FLAG_RCODE_REFUSED ( 5 << 0)
377		407
378	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	408	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
379	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)	409	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
380		410
		411	struct dns_cfg
		412	{
		413	static int next_uid;
		414
		415	u8 id1, id2, id3, id4;
		416
		417	u8 version;
		418	u8 flags;
		419	u8 rrtype;
		420	u8 def_ttl;
		421
		422	u16 client;
		423	u16 uid; // to make request unique
		424
		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;
		434
		435	void reset (int clientid);
		436	bool valid ();
		437	};
		438
		439	int dns_cfg::next_uid;
		440
		441	void dns_cfg::reset (int clientid)
		442	{
		443	id1 = 'G';
		444	id2 = 'V';
		445	id3 = 'P';
		446	id4 = 'E';
		447
		448	version = 1;
		449
		450	rrtype = RR_TYPE_TXT;
		451	flags = 0;
		452	def_ttl = 0;
		453	seq_cdc = 26;
		454	req_cdc = 62;
		455	rep_cdc = 0;
		456	max_size = htons (MAX_PKT_SIZE);
		457	client = htons (clientid);
		458	uid = next_uid++;
		459	delay = 0;
		460
		461	r3 = r4 = 0;
		462	r4 = r5 = r6 = r7 = 0;
		463	}
		464
		465	bool dns_cfg::valid ()
		466	{
		467	// although the protocol itself allows for some configurability,
		468	// only the following encoding/decoding settings are implemented.
		469	return id1 == 'G'
		470	&& id2 == 'V'
		471	&& id3 == 'P'
		472	&& id4 == 'E'
		473	&& seq_cdc == 26
		474	&& req_cdc == 62
		475	&& rep_cdc == 0
		476	&& version == 1;
		477	}
		478
381	struct dns_packet : net_packet	479	struct dns_packet : net_packet
382	{	480	{
383	u16 id;	481	u16 id;
384	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	482	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
385	u16 qdcount, ancount, nscount, arcount;	483	u16 qdcount, ancount, nscount, arcount;
386		484
387	u8 data[MAXSIZE - 6 * 2];	485	u8 data [MAXSIZE - 6 * 2];
388		486
389	int decode_label (char *data, int size, int &offs);	487	int decode_label (char *data, int size, int &offs);
390	};	488	};
391		489
392	int dns_packet::decode_label (char *data, int size, int &offs)	490	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
423	return data - orig;	521	return data - orig;
424	}	522	}
425		523
426	/////////////////////////////////////////////////////////////////////////////	524	/////////////////////////////////////////////////////////////////////////////
427		525
428	struct dns_req
429	{
430	dns_packet *pkt;
431	tstamp next;
432	int retry;
433	struct dns_connection *dns;
434	int seqno;
435
436	dns_req (dns_connection *dns);
437	void gen_stream_req (int seqno, byte_stream &stream);
438	};
439
440	static u16 dns_id = 12098; // TODO: should be per-vpn	526	static u16 dns_id = 0; // TODO: should be per-vpn
441		527
442	static u16 next_id ()	528	static u16 next_id ()
443	{	529	{
		530	if (!dns_id)
		531	dns_id = time (0);
		532
444	// the simplest lsfr with periodicity 65535 i could find	533	// the simplest lsfr with periodicity 65535 i could find
445	dns_id = (dns_id << 1)	534	dns_id = (dns_id << 1)
446	\| (((dns_id >> 1)	535	\| (((dns_id >> 1)
447	^ (dns_id >> 2)	536	^ (dns_id >> 2)
448	^ (dns_id >> 4)	537	^ (dns_id >> 4)
449	^ (dns_id >> 15)) & 1);	538	^ (dns_id >> 15)) & 1);
450		539
451	return dns_id;	540	return dns_id;
452	}	541	}
453		542
		543	struct dns_rcv;
		544	struct dns_snd;
		545
		546	struct dns_connection
		547	{
		548	connection *c;
		549	struct vpn *vpn;
		550
		551	dns_cfg cfg;
		552
		553	bool established;
		554
		555	tstamp last_received;
		556	tstamp last_sent;
		557	double min_latency;
		558	double poll_interval, send_interval;
		559
		560	vector<dns_rcv *> rcvpq;
		561
		562	byte_stream rcvdq; int rcvseq; int repseq;
		563	byte_stream snddq; int sndseq;
		564
		565	inline void time_cb (ev::timer &w, int revents); ev::timer tw;
		566	void receive_rep (dns_rcv *r);
		567
		568	dns_connection (connection *c);
		569	~dns_connection ();
		570	};
		571
		572	struct dns_snd
		573	{
		574	dns_packet *pkt;
		575	tstamp timeout, sent;
		576	int retry;
		577	struct dns_connection *dns;
		578	int seqno;
		579	bool stdhdr;
		580
		581	void gen_stream_req (int seqno, byte_stream &stream);
		582	void gen_syn_req ();
		583
		584	dns_snd (dns_connection *dns);
		585	~dns_snd ();
		586	};
		587
454	dns_req::dns_req (dns_connection *dns)	588	dns_snd::dns_snd (dns_connection *dns)
455	: dns (dns)	589	: dns (dns)
456	{	590	{
457	next = 0;	591	timeout = 0;
458	retry = 0;	592	retry = 0;
		593	seqno = 0;
		594	sent = ev_now ();
		595	stdhdr = false;
459		596
460	pkt = new dns_packet;	597	pkt = new dns_packet;
461		598
462	pkt->id = next_id ();	599	pkt->id = next_id ();
463	}	600	}
464		601
		602	dns_snd::~dns_snd ()
		603	{
		604	delete pkt;
		605	}
		606
		607	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		608	{
		609	// add tunnel domain
		610	for (;;)
		611	{
		612	const char *end = strchr (domain, '.');
		613
		614	if (!end)
		615	end = domain + strlen (domain);
		616
		617	int len = end - domain;
		618
		619	pkt [offs++] = len;
		620	memcpy (pkt.at (offs), domain, len);
		621	offs += len;
		622
		623	if (!*end)
		624	break;
		625
		626	domain = end + 1;
		627	}
		628	}
		629
465	void dns_req::gen_stream_req (int seqno, byte_stream &stream)	630	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
466	{	631	{
		632	stdhdr = true;
467	this->seqno = seqno;	633	this->seqno = seqno;
		634
		635	timeout = ev_now () + INITIAL_TIMEOUT;
468		636
469	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	637	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
470	pkt->qdcount = htons (1);	638	pkt->qdcount = htons (1);
471		639
472	int offs = 6*2;	640	int offs = 6*2;
473	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	641	int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
474	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	642	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
475	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra	643	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
476		644
477	char enc[256], *encp = enc;	645	char enc[256], *encp = enc;
478	encode_header (enc, THISNODE->id, seqno);	646	encode_header (enc, THISNODE->id, seqno);
…		…
496	encp += lbllen;	664	encp += lbllen;
497		665
498	enclen -= lbllen;	666	enclen -= lbllen;
499	}	667	}
500		668
501	const char *suffix = THISNODE->domain;	669	append_domain (*pkt, offs, dns->c->conf->domain);
502
503	// add tunnel domain
504	for (;;)
505	{
506	const char *end = strchr (suffix, '.');
507
508	if (!end)
509	end = suffix + strlen (suffix);
510
511	int len = end - suffix;
512
513	(*pkt)[offs++] = len;
514	memcpy (&((*pkt)[offs]), suffix, len);
515	offs += len;
516
517	if (!*end)
518	break;
519
520	suffix = end + 1;
521	}
522		670
523	(*pkt)[offs++] = 0;	671	(*pkt)[offs++] = 0;
524	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	672	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		673	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		674
		675	pkt->len = offs;
		676	}
		677
		678	void dns_snd::gen_syn_req ()
		679	{
		680	timeout = ev_now () + INITIAL_SYN_TIMEOUT;
		681
		682	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		683	pkt->qdcount = htons (1);
		684
		685	int offs = 6 * 2;
		686
		687	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
		688
		689	assert (elen <= MAX_LBL_SIZE);
		690
		691	(*pkt)[offs] = elen;
		692	offs += elen + 1;
		693	append_domain (*pkt, offs, dns->c->conf->domain);
		694
		695	(*pkt)[offs++] = 0;
		696	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
525	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	697	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
526		698
527	pkt->len = offs;	699	pkt->len = offs;
528	}	700	}
529		701
…		…
549	delete pkt;	721	delete pkt;
550	}	722	}
551		723
552	/////////////////////////////////////////////////////////////////////////////	724	/////////////////////////////////////////////////////////////////////////////
553		725
554	struct dns_connection
555	{
556	connection *c;
557	struct vpn *vpn;
558
559	vector<dns_rcv *> rcvpq;
560
561	int rcvseq;
562	int sndseq;
563
564	byte_stream rcvdq;
565	byte_stream snddq;
566
567	void time_cb (time_watcher &w); time_watcher tw;
568	void receive_rep (dns_rcv *r);
569
570	dns_connection (connection *c);
571	~dns_connection ();
572	};
573
574	dns_connection::dns_connection (connection *c)	726	dns_connection::dns_connection (connection *c)
575	: c (c)	727	: c (c)
576	, rcvdq (MAX_BACKLOG * 2)	728	, rcvdq (MAX_BACKLOG * 2)
577	, snddq (MAX_BACKLOG * 2)	729	, snddq (MAX_BACKLOG)
578	, tw (this, &dns_connection::time_cb)
579	{	730	{
		731	tw.set<dns_connection, &dns_connection::time_cb> (this);
		732
580	vpn = c->vpn;	733	vpn = c->vpn;
581		734
		735	established = false;
		736
582	rcvseq = sndseq = 0;	737	rcvseq = repseq = sndseq = 0;
		738
		739	last_sent = last_received = 0;
		740	poll_interval = 0.5; // starting here
		741	send_interval = 0.5; // starting rate
		742	min_latency = INITIAL_TIMEOUT;
583	}	743	}
584		744
585	dns_connection::~dns_connection ()	745	dns_connection::~dns_connection ()
586	{	746	{
587	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();	747	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
588	i != rcvpq.end ();	748	i != rcvpq.end ();
589	++i)	749	++i)
590	delete *i;	750	delete *i;
591	}	751	}
592		752
593	struct dns_cfg
594	{
595	u8 id1, id2, id3;
596	u8 def_ttl;
597	u8 unused1;
598	u16 max_size;
599	u8 flags1, flags2;
600	};
601
602	void dns_connection::receive_rep (dns_rcv *r)	753	void dns_connection::receive_rep (dns_rcv *r)
603	{	754	{
		755	if (r->datalen)
		756	{
		757	last_received = ev_now ();
		758	tw ();
		759
		760	poll_interval = send_interval;
		761	}
		762	else
		763	{
		764	poll_interval *= 1.5;
		765
		766	if (poll_interval > MAX_POLL_INTERVAL)
		767	poll_interval = MAX_POLL_INTERVAL;
		768	}
		769
604	rcvpq.push_back (r);	770	rcvpq.push_back (r);
605		771
606	redo:	772	redo:
607		773
608	// find next packet	774	// find next packet
609	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )	775	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
610	if (SEQNO_EQ (rcvseq, (*i)->seqno))	776	if (SEQNO_EQ (rcvseq, (*i)->seqno))
611	{	777	{
		778	//printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
612	// enter the packet into our input stream	779	// enter the packet into our input stream
613	r = *i;	780	r = *i;
614		781
615	// remove the oldest packet, look forward, as it's oldest first	782	// remove the oldest packet, look forward, as it's oldest first
616	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)	783	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
617	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))	784	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
618	{	785	{
		786	//printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
619	delete *j;	787	delete *j;
620	rcvpq.erase (j);	788	rcvpq.erase (j);
621	break;	789	break;
622	}	790	}
623		791
624	rcvseq = (rcvseq + 1) & SEQNO_MASK;	792	rcvseq = (rcvseq + 1) & SEQNO_MASK;
625		793
626	if (!rcvdq.put (r->data, r->datalen))	794	if (!rcvdq.put (r->data, r->datalen))
		795	{
		796	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
627	abort (); // MUST never overflow, can be caused by data corruption, TODO	797	abort (); // MUST never overflow, can be caused by data corruption, TODO
		798	}
628		799
629	while (vpn_packet *pkt = rcvdq.get ())	800	while (vpn_packet *pkt = rcvdq.get ())
630	{	801	{
631	sockinfo si;	802	sockinfo si;
632	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	803	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
633		804
634	vpn->recv_vpn_packet (pkt, si);	805	vpn->recv_vpn_packet (pkt, si);
		806
		807	delete pkt;
635	}	808	}
636		809
637	// check for further packets	810	// check for further packets
638	goto redo;	811	goto redo;
639	}	812	}
640	}	813	}
641		814
642	dns_packet *	815	void
643	vpn::dnsv4_server (dns_packet *pkt)	816	vpn::dnsv4_server (dns_packet &pkt)
644	{	817	{
645	u16 flags = ntohs (pkt->flags);	818	u16 flags = ntohs (pkt.flags);
646		819
647	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
648	int offs = 6 * 2; // skip header	820	int offs = 6 * 2; // skip header
649		821
650	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	822	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
651		823
652	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	824	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
653	&& pkt->qdcount == htons (1))	825	&& pkt.qdcount == htons (1))
654	{	826	{
655	char qname[MAXSIZE];	827	char qname [MAXSIZE];
656	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	828	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
657		829
658	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	830	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
659	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	831	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
660		832
661	pkt->qdcount = htons (1);	833	pkt.qdcount = htons (1);
662	pkt->ancount = 0;	834	pkt.ancount = 0;
663	pkt->nscount = 0; // should be self, as other nameservers reply like this	835	pkt.nscount = 0; // should be self, as other nameservers reply like this
664	pkt->arcount = 0; // a record for self, as other nameservers reply like this	836	pkt.arcount = 0; // a record for self, as other nameservers reply like this
665		837
666	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	838	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
667		839
668	int dlen = strlen (THISNODE->domain);	840	int dlen = strlen (THISNODE->domain);
669		841
670	if (qclass == RR_CLASS_IN	842	if (qclass == RR_CLASS_IN
671	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
672	&& qlen > dlen + 1 + HDRSIZE	843	&& qlen > dlen + 1
673	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	844	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
674	{	845	{
675	// correct class, domain: parse	846	// now generate reply
676	int client, seqno;	847	pkt.ancount = htons (1); // one answer RR
677	decode_header (qname, client, seqno);	848	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
678		849
679	u8 data[MAXSIZE];	850	if ((qtype == RR_TYPE_ANY
680	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	851	\|\| qtype == RR_TYPE_TXT
681		852	\|\| qtype == RR_TYPE_NULL)
682	if (0 < client && client <= conns.size ())	853	&& qlen > dlen + 1 + HDRSIZE)
683	{	854	{
		855	// correct class, domain: parse
		856	int client, seqno;
		857	decode_header (qname, client, seqno);
		858
		859	u8 data[MAXSIZE];
		860	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
		861
		862	if (0 < client && client <= conns.size ())
		863	{
684	connection *c = conns [client - 1];	864	connection *c = conns [client - 1];
685
686	if (!c->dns)
687	c->dns = new dns_connection (c);
688
689	dns_connection *dns = c->dns;	865	dns_connection *dns = c->dns;
		866	dns_rcv *rcv;
690		867
		868	if (dns)
		869	{
691	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )	870	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
692	if (SEQNO_EQ ((*i)->seqno, seqno))	871	if (SEQNO_EQ ((*i)->seqno, seqno))
		872	{
		873	// already seen that request: simply reply with the cached reply
		874	dns_rcv r = i;
		875
		876	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		877
		878	// refresh header & id, as the retry count could have changed
		879	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		880	r->pkt->id = pkt.id;
		881
		882	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		883
		884	goto duplicate_request;
		885	}
		886
		887	// new packet, queue
		888	rcv = new dns_rcv (seqno, data, datalen);
		889	dns->receive_rep (rcv);
		890	}
		891
693	{	892	{
694	// already seen that request: simply reply with the cached reply	893	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
695	dns_rcv r = i;
696		894
697	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	895	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		896	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		897	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		898	pkt [offs++] = 0; pkt [offs++] = 0;
		899	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
698		900
699	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);	901	int rdlen_offs = offs += 2;
700	pkt->id = r->pkt->id;	902
701	goto duplicate_request;	903	if (dns)
		904	{
		905	int dlen = ntohs (dns->cfg.max_size) - offs;
		906
		907	// bind doesn't compress well, so reduce further by one label length
		908	dlen -= qlen;
		909
		910	// only put data into in-order sequence packets, if
		911	// we receive out-of-order packets we generate empty
		912	// replies
		913	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		914	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
		915	{
		916	dns->repseq = seqno;
		917
		918	while (dlen > 1 && !dns->snddq.empty ())
		919	{
		920	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		921
		922	if (txtlen > dns->snddq.size ())
		923	txtlen = dns->snddq.size ();
		924
		925	pkt[offs++] = txtlen;
		926	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
		927	offs += txtlen;
		928	dns->snddq.remove (txtlen);
		929
		930	dlen -= txtlen + 1;
		931	}
		932	}
		933
		934	// avoid completely empty TXT rdata
		935	if (offs == rdlen_offs)
		936	pkt[offs++] = 0;
		937
		938	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
		939	}
		940	else
		941	{
		942	// send RST
		943	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		944	pkt [offs++] = CMD_IP_RST;
		945	}
		946
		947	int rdlen = offs - rdlen_offs;
		948
		949	pkt [rdlen_offs - 2] = rdlen >> 8;
		950	pkt [rdlen_offs - 1] = rdlen;
		951
		952	if (dns)
		953	{
		954	// now update dns_rcv copy
		955	rcv->pkt->len = offs;
		956	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		957	}
702	}	958	}
703		959
704	// new packet, queue	960	duplicate_request: ;
705	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);	961	}
706	dns->receive_rep (rcv);	962	else
707
708	// now generate reply
709	pkt->ancount = htons (1); // one answer RR
710	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	963	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		964	}
		965	else if (qtype == RR_TYPE_A
		966	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		967	{
		968	dns_cfg cfg;
		969	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		970	int client = ntohs (cfg.client);
711		971
712	(*pkt) [offs++] = 0xc0;
713	(pkt) [offs++] = 6 2; // same as in query section	972	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
714		973
715	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;	974	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
716	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;	975	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
717
718	(pkt) [offs++] = 0; (pkt) [offs++] = 0;	976	pkt [offs++] = 0; pkt [offs++] = 0;
719	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL	977	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		978	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
720		979
721	int dlen = MAX_PKT_SIZE - offs - 2;	980	slog (L_INFO, _("DNS: client %d connects"), client);
722		981
723	// bind doesn't compress well, so reduce further by one label length	982	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
724	dlen -= qlen;	983	pkt [offs++] = CMD_IP_REJ;
725		984
726	int rdlen_offs = offs += 2;	985	if (0 < client && client <= conns.size ())
727
728	while (dlen > 1 && !dns->snddq.empty ())
729	{	986	{
730	int txtlen = dlen <= 255 ? dlen - 1 : 255;	987	connection *c = conns [client - 1];
731		988
732	if (txtlen > dns->snddq.size ())	989	if (cfg.valid ())
733	txtlen = dns->snddq.size ();	990	{
		991	pkt [offs - 1] = CMD_IP_SYN;
734		992
735	(*pkt)[offs++] = txtlen;	993	delete c->dns;
736	memcpy (pkt->at (offs), dns->snddq.begin (), txtlen);	994	c->dns = new dns_connection (c);
737	offs += txtlen;	995	c->dns->cfg = cfg;
738	dns->snddq.remove (txtlen);	996	}
739
740	dlen -= txtlen + 1;
741	}	997	}
742
743	// avoid empty TXT rdata
744	if (offs == rdlen_offs)
745	(*pkt)[offs++] = 0;
746
747	int rdlen = offs - rdlen_offs;
748
749	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
750	(*pkt) [rdlen_offs - 1] = rdlen;
751
752	// now update dns_rcv copy
753	rcv->pkt->len = offs;
754	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
755
756	duplicate_request: ;
757	}	998	}
758	else
759	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
760	}	999	}
761		1000
762	pkt->len = offs;	1001	pkt.len = offs;
763	}	1002	}
764
765	return pkt;
766	}	1003	}
767		1004
768	void	1005	void
769	vpn::dnsv4_client (dns_packet *pkt)	1006	vpn::dnsv4_client (dns_packet &pkt)
770	{	1007	{
771	u16 flags = ntohs (pkt->flags);	1008	u16 flags = ntohs (pkt.flags);
772	int offs = 6 * 2; // skip header	1009	int offs = 6 * 2; // skip header
773		1010
774	pkt->qdcount = ntohs (pkt->qdcount);	1011	pkt.qdcount = ntohs (pkt.qdcount);
775	pkt->ancount = ntohs (pkt->ancount);	1012	pkt.ancount = ntohs (pkt.ancount);
776		1013
777	// go through our request list and find the corresponding request	1014	// go through our request list and find the corresponding request
778	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	1015	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
779	i != dns_sndpq.end ();	1016	i != dns_sndpq.end ();
780	++i)	1017	++i)
781	if ((*i)->pkt->id == pkt->id)	1018	if ((*i)->pkt->id == pkt.id)
782	{	1019	{
783	dns_connection dns = (i)->dns;	1020	dns_connection dns = (i)->dns;
		1021	connection *c = dns->c;
784	int seqno = (*i)->seqno;	1022	int seqno = (*i)->seqno;
785	u8 data[MAXSIZE], *datap = data;	1023	u8 data[MAXSIZE], *datap = data;
		1024	//printf ("rcv pkt %x\n", seqno);//D
		1025
		1026	if ((*i)->retry)
		1027	{
		1028	dns->send_interval *= 1.01;
		1029	if (dns->send_interval > MAX_SEND_INTERVAL)
		1030	dns->send_interval = MAX_SEND_INTERVAL;
		1031	}
		1032	else
		1033	{
		1034	#if 0
		1035	dns->send_interval *= 0.999;
		1036	#endif
		1037	// the latency surely puts an upper bound on
		1038	// the minimum send interval
		1039	double latency = ev_now () - (*i)->sent;
		1040
		1041	if (latency < dns->min_latency)
		1042	dns->min_latency = latency;
		1043
		1044	if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
		1045	dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
		1046
		1047	if (dns->send_interval < conf.dns_send_interval)
		1048	dns->send_interval = conf.dns_send_interval;
		1049	}
786		1050
787	delete *i;	1051	delete *i;
788	dns_sndpq.erase (i);	1052	dns_sndpq.erase (i);
789		1053
790	if (flags & FLAG_RESPONSE && !(flags & (FLAG_OP_MASK \| FLAG_TC)))	1054	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
791	{	1055	{
792	char qname[MAXSIZE];	1056	char qname[MAXSIZE];
793		1057
794	while (pkt->qdcount-- && offs < MAXSIZE - 4)	1058	while (pkt.qdcount-- && offs < MAXSIZE - 4)
795	{	1059	{
796	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1060	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
797	offs += 4; // skip qtype, qclass	1061	offs += 4; // skip qtype, qclass
798	}	1062	}
799		1063
800	while (pkt->ancount-- && offs < MAXSIZE - 10 && datap)	1064	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
801	{	1065	{
802	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1066	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
803		1067
804	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1068	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
805	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1069	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
806	u32 ttl = (*pkt) [offs++] << 24;	1070	u32 ttl = pkt [offs++] << 24;
807	ttl \|= (*pkt) [offs++] << 16;	1071	ttl \|= pkt [offs++] << 16;
808	ttl \|= (*pkt) [offs++] << 8;	1072	ttl \|= pkt [offs++] << 8;
809	ttl \|= (*pkt) [offs++];	1073	ttl \|= pkt [offs++];
810
811	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1074	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
812		1075
813	if (rdlen <= MAXSIZE - offs)	1076	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
814	{	1077	{
815	// decode bytes, finally	1078	if (rdlen <= MAXSIZE - offs)
816
817	while (rdlen)
818	{	1079	{
		1080	// decode bytes, finally
		1081
		1082	while (rdlen)
		1083	{
819	int txtlen = (*pkt) [offs++];	1084	int txtlen = pkt [offs++];
820		1085
821	assert (txtlen + offs < MAXSIZE - 1);	1086	assert (txtlen + offs < MAXSIZE - 1);
822		1087
823	memcpy (datap, pkt->at (offs), txtlen);	1088	memcpy (datap, pkt.at (offs), txtlen);
824	datap += txtlen; offs += txtlen;	1089	datap += txtlen; offs += txtlen;
825		1090
826	rdlen -= txtlen + 1;	1091	rdlen -= txtlen + 1;
		1092	}
827	}	1093	}
828	}	1094	}
		1095	else if (qtype == RR_TYPE_A)
		1096	{
		1097	u8 ip [4];
		1098
		1099	ip [0] = pkt [offs++];
		1100	ip [1] = pkt [offs++];
		1101	ip [2] = pkt [offs++];
		1102	ip [3] = pkt [offs++];
		1103
		1104	if (ip [0] == CMD_IP_1
		1105	&& ip [1] == CMD_IP_2
		1106	&& ip [2] == CMD_IP_3)
		1107	{
		1108	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
		1109
		1110	if (ip [3] == CMD_IP_RST)
		1111	{
		1112	slog (L_DEBUG, _("DNS: got tunnel RST request"));
		1113
		1114	delete dns; c->dns = 0;
		1115
		1116	return;
		1117	}
		1118	else if (ip [3] == CMD_IP_SYN)
		1119	{
		1120	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
		1121	dns->established = true;
		1122	}
		1123	else if (ip [3] == CMD_IP_REJ)
		1124	{
		1125	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1126	abort ();
		1127	}
		1128	else
		1129	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
		1130	}
		1131	else
		1132	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
		1133	ip [0], ip [1], ip [2], ip [3]);
		1134
		1135	return;
		1136	}
829		1137
830	int client, rseqno;	1138	int client, rseqno;
831	decode_header (qname, client, rseqno);	1139	decode_header (qname, client, rseqno);
832		1140
833	if (client != THISNODE->id)	1141	if (client != THISNODE->id)
834	{	1142	{
835	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));	1143	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
836	datap = 0;	1144	datap = 0;
837	}	1145	}
838	else if (rseqno != seqno)	1146	else if (rseqno != seqno)
839	{	1147	{
840	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));	1148	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
841	datap = 0;	1149	datap = 0;
842	}	1150	}
843	}	1151	}
844	}	1152	}
845		1153
…		…
847	if (datap)	1155	if (datap)
848	dns->receive_rep (new dns_rcv (seqno, data, datap - data));	1156	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
849		1157
850	break;	1158	break;
851	}	1159	}
852
853	delete pkt;
854	}	1160	}
855		1161
856	void	1162	void
857	vpn::dnsv4_ev (io_watcher &w, short revents)	1163	vpn::dnsv4_ev (ev::io &w, int revents)
858	{	1164	{
859	if (revents & EVENT_READ)	1165	if (revents & EV_READ)
860	{	1166	{
861	dns_packet *pkt = new dns_packet;	1167	dns_packet *pkt = new dns_packet;
862	struct sockaddr_in sa;	1168	struct sockaddr_in sa;
863	socklen_t sa_len = sizeof (sa);	1169	socklen_t sa_len = sizeof (sa);
864		1170
865	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1171	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
866		1172
867	if (pkt->len > 0)	1173	if (pkt->len > 0)
868	{	1174	{
869	if (pkt->flags & htons (FLAG_TC))	1175	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1176	dnsv4_client (*pkt);
		1177	else
870	{	1178	{
871	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));	1179	dnsv4_server (*pkt);
872	//TODO connection reset	1180	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
873	}	1181	}
874		1182
875	if (THISNODE->dns_port)	1183	delete pkt;
876	{
877	pkt = dnsv4_server (pkt);
878	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);
879	}
880	else
881	dnsv4_client (pkt);
882	}	1184	}
883	}	1185	}
884	}	1186	}
885		1187
886	bool	1188	bool
887	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1189	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
888	{	1190	{
		1191	int client = ntohl (si.host);
		1192
		1193	assert (0 < client && client <= conns.size ());
		1194
		1195	connection *c = conns [client - 1];
		1196
889	if (!dns)	1197	if (!c->dns)
890	dns = new dns_connection (this);	1198	c->dns = new dns_connection (c);
891		1199
892	if (!dns->snddq.put (pkt))	1200	if (c->dns->snddq.put (pkt))
893	return false;	1201	c->dns->tw ();
894		1202
895	// start timer if neccessary	1203	// always return true even if the buffer overflows
896	if (!THISNODE->dns_port && !dns->tw.active)
897	dns->tw.trigger ();
898
899	return true;	1204	return true;
900	}	1205	}
901		1206
902	void	1207	void
903	dns_connection::time_cb (time_watcher &w)	1208	connection::dnsv4_reset_connection ()
904	{	1209	{
		1210	//delete dns; dns = 0; //TODO
		1211	}
		1212
		1213	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1214
		1215	void
		1216	dns_connection::time_cb (ev::timer &w, int revents)
		1217	{
		1218	// servers have to be polled
		1219	if (THISNODE->dns_port)
		1220	return;
		1221
905	// check for timeouts and (re)transmit	1222	// check for timeouts and (re)transmit
906	tstamp next = NOW + 60;	1223	tstamp next = ev::now () + poll_interval;
907	dns_req *send = 0;	1224	dns_snd *send = 0;
908		1225
909	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1226	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
910	i != vpn->dns_sndpq.end ();	1227	i != vpn->dns_sndpq.end ();
911	++i)	1228	++i)
912	{	1229	{
913	dns_req r = i;	1230	dns_snd r = i;
914		1231
915	if (r->next <= NOW)	1232	if (r->timeout <= ev_now ())
916	{	1233	{
917	if (!send)	1234	if (!send)
918	{	1235	{
919	send = r;	1236	send = r;
920		1237
921	if (r->retry)//D
922	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
923	r->retry++;	1238	r->retry++;
924	r->next = NOW + r->retry;	1239	r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
		1240	//printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D
		1241
		1242	// the following code changes the query section a bit, forcing
		1243	// the forwarder to generate a new request
		1244	if (r->stdhdr)
		1245	encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
925	}	1246	}
926	}	1247	}
927		1248	else
928	if (r->next < next)	1249	NEXT (r->timeout);
929	next = r->next;
930	}	1250	}
931		1251
932	if (!send	1252	if (!send)
933	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)
934	{	1253	{
		1254	// generate a new packet, if wise
		1255
		1256	if (!established)
		1257	{
		1258	if (vpn->dns_sndpq.empty ())
		1259	{
935	send = new dns_req (this);	1260	send = new dns_snd (this);
		1261
		1262	cfg.reset (THISNODE->id);
		1263	send->gen_syn_req ();
		1264	}
		1265	}
		1266	else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
		1267	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1268	{
		1269	if (last_sent + send_interval <= ev_now ())
		1270	{
		1271	//printf ("sending data request etc.\n"); //D
		1272	if (!snddq.empty () \|\| last_received + 1. > ev_now ())
		1273	{
		1274	poll_interval = send_interval;
		1275	NEXT (ev_now () + send_interval);
		1276	}
		1277
		1278	send = new dns_snd (this);
936	send->gen_stream_req (sndseq, snddq);	1279	send->gen_stream_req (sndseq, snddq);
		1280	send->timeout = ev_now () + min_latency * conf.dns_timeout_factor;
		1281	//printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D
		1282
		1283	sndseq = (sndseq + 1) & SEQNO_MASK;
		1284	}
		1285	else
		1286	NEXT (last_sent + send_interval);
		1287	}
		1288
		1289	if (send)
937	vpn->dns_sndpq.push_back (send);	1290	vpn->dns_sndpq.push_back (send);
938
939	sndseq = (sndseq + 1) & SEQNO_MASK;
940	}	1291	}
941
942	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
943		1292
944	if (send)	1293	if (send)
945	{	1294	{
946	dns_packet *pkt = send->pkt;	1295	last_sent = ev_now ();
947		1296	sendto (vpn->dnsv4_fd,
948	next = min_next;	1297	send->pkt->at (0), send->pkt->len, 0,
949
950	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0,
951	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());	1298	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
952	}	1299	}
953	else if (next < min_next)
954	next = min_next;
955		1300
956	w.start (next);	1301	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1302	poll_interval, send_interval, next - ev_now (),
		1303	vpn->dns_sndpq.size (), snddq.size (),
		1304	rcvpq.size ());
		1305
		1306	// TODO: no idea when this happens, but when next < ev_now (), we have a problem
		1307	// doesn't seem to happen anymore
		1308	if (next < ev_now () + 0.001)
		1309	next = ev_now () + 0.1;
		1310
		1311	w.start (next - ev_now ());
957	}	1312	}
958		1313
959	#endif	1314	#endif
960		1315

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs. Revision 1.46 by pcg, Thu Dec 6 00:35:29 2007 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC vs.
Revision 1.46 by pcg, Thu Dec 6 00:35:29 2007 UTC