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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs.
Revision 1.42 by pcg, Sat Nov 10 05:14:22 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>
…		…
43		48
44	#include "netcompat.h"	49	#include "netcompat.h"
45		50
46	#include "vpn.h"	51	#include "vpn.h"
47		52
48	#define MIN_RETRY 1.	53	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
49	#define MAX_RETRY 60.	54	#define ACTIVITY_INTERVAL 5.
50		55
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	56	#define INITIAL_TIMEOUT 0.1 // retry timeouts
		57	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
		58
		59	#define MAX_SEND_INTERVAL 2. // optimistic?
		60
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	61	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
53	#define MAX_RATE 10000 // requests/s
54	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	62	#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55		63
56	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	64	#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well
57	// 240 leaves about 4 bytes of server reply data	65	// 240 leaves about 4 bytes of server reply data
58	// every two request byte sless give room for one reply byte	66	// every request byte less give room for two reply bytes
59		67
60	// seqno has 12 bits (3 bytes a 4 bits in the header)
61	#define SEQNO_MASK 0x7fff	68	#define SEQNO_MASK 0x3fff
62	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	69	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
63		70
64	#define MAX_LBL_SIZE 63	71	#define MAX_LBL_SIZE 63
65	#define MAX_PKT_SIZE 512	72	#define MAX_PKT_SIZE 512
66		73
		74	#define RR_TYPE_A 1
		75	#define RR_TYPE_NULL 10
67	#define RR_TYPE_TXT 16	76	#define RR_TYPE_TXT 16
68	#define RR_TYPE_ANY 255	77	#define RR_TYPE_ANY 255
		78
69	#define RR_CLASS_IN 1	79	#define RR_CLASS_IN 1
		80
		81	#define CMD_IP_1 207
		82	#define CMD_IP_2 46
		83	#define CMD_IP_3 236
		84	#define CMD_IP_RST 29
		85	#define CMD_IP_SYN 113
		86	#define CMD_IP_REJ 32
70		87
71	// works for cmaps up to 255 (not 256!)	88	// works for cmaps up to 255 (not 256!)
72	struct charmap	89	struct charmap
73	{	90	{
74	enum { INVALID = (u8)255 };	91	enum { INVALID = (u8)255 };
…		…
154	return dec_len [len];	171	return dec_len [len];
155	}	172	}
156		173
157	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	174	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
158	{	175	{
159	if (!len)	176	if (!len \|\| len > MAX_DEC_LEN)
160	return 0;	177	return 0;
161		178
162	int elen = encode_len (len);	179	int elen = encode_len (len);
163		180
164	mp_limb_t m [MAX_LIMBS];	181	mp_limb_t m [MAX_LIMBS];
…		…
183	return elen;	200	return elen;
184	}	201	}
185		202
186	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	203	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
187	{	204	{
188	if (!len)	205	if (!len \|\| len > MAX_ENC_LEN)
189	return 0;	206	return 0;
190		207
191	u8 src_ [MAX_ENC_LEN];	208	u8 src_ [MAX_ENC_LEN];
192	unsigned int elen = 0;	209	unsigned int elen = 0;
193		210
…		…
240	}	257	}
241	abort ();	258	abort ();
242	}	259	}
243	#endif	260	#endif
244		261
245	// the following sequence has been crafted to	262	//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
246	// a) look somewhat random
247	// b) the even (and odd) indices never share the same character as upper/lowercase
248	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)
249	// the other sequences are obviously derived
250	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	263	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	264	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
252	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	265	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
253	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	266	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
254		267
255	/////////////////////////////////////////////////////////////////////////////	268	/////////////////////////////////////////////////////////////////////////////
256		269
257	#define HDRSIZE 6	270	#define HDRSIZE 6
258		271
259	inline void encode_header (char *data, int clientid, int seqno)	272	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
260	{	273	{
261	u8 hdr[3] = { clientid, seqno >> 8, seqno };	274	seqno &= SEQNO_MASK;
		275
		276	u8 hdr[3] = {
		277	clientid,
		278	(seqno >> 8) \| (retry << 6),
		279	seqno,
		280	};
262		281
263	assert (clientid < 256);	282	assert (clientid < 256);
264		283
265	cdc26.encode (data, hdr, 3);	284	cdc26.encode (data, hdr, 3);
266	}	285	}
…		…
269	{	288	{
270	u8 hdr[3];	289	u8 hdr[3];
271		290
272	cdc26.decode (hdr, data, HDRSIZE);	291	cdc26.decode (hdr, data, HDRSIZE);
273		292
274	printf ("DEC %02x %02x %02x %02x\n", hdr[0], hdr[1], hdr[2], hdr[3]);
275
276	clientid = hdr[0];	293	clientid = hdr[0];
277	seqno = (hdr[1] << 8) \| hdr[2];	294	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
278	}	295	}
279		296
280	/////////////////////////////////////////////////////////////////////////////	297	/////////////////////////////////////////////////////////////////////////////
281		298
282	struct byte_stream	299	struct byte_stream
…		…
311	}	328	}
312		329
313	void byte_stream::remove (int count)	330	void byte_stream::remove (int count)
314	{	331	{
315	if (count > fill)	332	if (count > fill)
316	abort ();	333	assert (count <= fill);
317		334
318	memmove (data, data + count, fill -= count);	335	memmove (data, data + count, fill -= count);
319	}	336	}
320		337
321	bool byte_stream::put (u8 *data, unsigned int datalen)	338	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
334	return false;	351	return false;
335		352
336	data [fill++] = pkt->len >> 8;	353	data [fill++] = pkt->len >> 8;
337	data [fill++] = pkt->len;	354	data [fill++] = pkt->len;
338		355
339	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	356	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
340		357
341	return true;	358	return true;
342	}	359	}
343		360
344	vpn_packet *byte_stream::get ()	361	vpn_packet *byte_stream::get ()
345	{	362	{
		363	unsigned int len;
		364
		365	for (;;)
		366	{
346	int len = (data [0] << 8) \| data [1];	367	len = (data [0] << 8) \| data [1];
347		368
348	if (len > MAXSIZE && fill >= 2)	369	if (len <= MAXSIZE \|\| fill < 2)
349	abort (); // TODO handle this gracefully, connection reset	370	break;
350		371
		372	// TODO: handle this better than skipping, e.g. by reset
		373	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		374	remove (1);
		375	}
		376
351	if (fill < len + 2)	377	if (fill < len + 2)
352	return 0;	378	return 0;
353		379
354	vpn_packet *pkt = new vpn_packet;	380	vpn_packet *pkt = new vpn_packet;
355		381
356	pkt->len = len;	382	pkt->len = len;
357	memcpy (&((*pkt)[0]), data + 2, len);	383	memcpy (pkt->at (0), data + 2, len);
358	remove (len + 2);	384	remove (len + 2);
359		385
360	return pkt;	386	return pkt;
361	}	387	}
362		388
363	/////////////////////////////////////////////////////////////////////////////	389	/////////////////////////////////////////////////////////////////////////////
364		390
365	#define FLAG_QUERY ( 0 << 15)	391	#define FLAG_QUERY ( 0 << 15)
366	#define FLAG_RESPONSE ( 1 << 15)	392	#define FLAG_RESPONSE ( 1 << 15)
367	#define FLAG_OP_MASK (15 << 14)	393	#define FLAG_OP_MASK (15 << 11)
368	#define FLAG_OP_QUERY ( 0 << 11)	394	#define FLAG_OP_QUERY ( 0 << 11)
369	#define FLAG_AA ( 1 << 10)	395	#define FLAG_AA ( 1 << 10)
370	#define FLAG_TC ( 1 << 9)	396	#define FLAG_TC ( 1 << 9)
371	#define FLAG_RD ( 1 << 8)	397	#define FLAG_RD ( 1 << 8)
372	#define FLAG_RA ( 1 << 7)	398	#define FLAG_RA ( 1 << 7)
…		…
379	#define FLAG_RCODE_REFUSED ( 5 << 0)	405	#define FLAG_RCODE_REFUSED ( 5 << 0)
380		406
381	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	407	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
382	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)	408	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
383		409
		410	struct dns_cfg
		411	{
		412	static int next_uid;
		413
		414	u8 id1, id2, id3, id4;
		415
		416	u8 version;
		417	u8 flags;
		418	u8 rrtype;
		419	u8 def_ttl;
		420
		421	u16 client;
		422	u16 uid; // to make request unique
		423
		424	u16 max_size;
		425	u8 seq_cdc;
		426	u8 req_cdc;
		427
		428	u8 rep_cdc;
		429	u8 delay; // time in 0.01s units that the server may delay replying packets
		430	u8 r3, r4;
		431
		432	u8 r5, r6, r7, r8;
		433
		434	void reset (int clientid);
		435	bool valid ();
		436	};
		437
		438	int dns_cfg::next_uid;
		439
		440	void dns_cfg::reset (int clientid)
		441	{
		442	id1 = 'G';
		443	id2 = 'V';
		444	id3 = 'P';
		445	id4 = 'E';
		446
		447	version = 1;
		448
		449	rrtype = RR_TYPE_TXT;
		450	flags = 0;
		451	def_ttl = 0;
		452	seq_cdc = 26;
		453	req_cdc = 62;
		454	rep_cdc = 0;
		455	max_size = htons (MAX_PKT_SIZE);
		456	client = htons (clientid);
		457	uid = next_uid++;
		458	delay = 0;
		459
		460	r3 = r4 = 0;
		461	r4 = r5 = r6 = r7 = 0;
		462	}
		463
		464	bool dns_cfg::valid ()
		465	{
		466	// although the protocol itself allows for some configurability,
		467	// only the following encoding/decoding settings are implemented.
		468	return id1 == 'G'
		469	&& id2 == 'V'
		470	&& id3 == 'P'
		471	&& id4 == 'E'
		472	&& seq_cdc == 26
		473	&& req_cdc == 62
		474	&& rep_cdc == 0
		475	&& version == 1;
		476	}
		477
384	struct dns_packet : net_packet	478	struct dns_packet : net_packet
385	{	479	{
386	u16 id;	480	u16 id;
387	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	481	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
388	u16 qdcount, ancount, nscount, arcount;	482	u16 qdcount, ancount, nscount, arcount;
389		483
390	u8 data[MAXSIZE - 6 * 2];	484	u8 data [MAXSIZE - 6 * 2];
391		485
392	int decode_label (char *data, int size, int &offs);	486	int decode_label (char *data, int size, int &offs);
393	};	487	};
394		488
395	int dns_packet::decode_label (char *data, int size, int &offs)	489	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
426	return data - orig;	520	return data - orig;
427	}	521	}
428		522
429	/////////////////////////////////////////////////////////////////////////////	523	/////////////////////////////////////////////////////////////////////////////
430		524
431	struct dns_req
432	{
433	dns_packet *pkt;
434	tstamp next;
435	int retry;
436	connection *conn;
437	int seqno;
438
439	dns_req (connection *c);
440	void gen_stream_req (int seqno, byte_stream *stream);
441	};
442
443	static u16 dns_id = 12098; // TODO: should be per-vpn	525	static u16 dns_id = 0; // TODO: should be per-vpn
444		526
445	static u16 next_id ()	527	static u16 next_id ()
446	{	528	{
		529	if (!dns_id)
		530	dns_id = time (0);
		531
447	// the simplest lsfr with periodicity 65535 i could find	532	// the simplest lsfr with periodicity 65535 i could find
448	dns_id = (dns_id << 1)	533	dns_id = (dns_id << 1)
449	\| (((dns_id >> 1)	534	\| (((dns_id >> 1)
450	^ (dns_id >> 2)	535	^ (dns_id >> 2)
451	^ (dns_id >> 4)	536	^ (dns_id >> 4)
452	^ (dns_id >> 15)) & 1);	537	^ (dns_id >> 15)) & 1);
453		538
454	return dns_id;	539	return dns_id;
455	}	540	}
456		541
457	dns_req::dns_req (connection *c)	542	struct dns_rcv;
458	: conn (c)	543	struct dns_snd;
		544
		545	struct dns_connection
459	{	546	{
460	next = 0;	547	connection *c;
		548	struct vpn *vpn;
		549
		550	dns_cfg cfg;
		551
		552	bool established;
		553
		554	tstamp last_received;
		555	tstamp last_sent;
		556	double min_latency;
		557	double poll_interval, send_interval;
		558
		559	vector<dns_rcv *> rcvpq;
		560
		561	byte_stream rcvdq; int rcvseq; int repseq;
		562	byte_stream snddq; int sndseq;
		563
		564	void time_cb (ev::timer &w, int revents); ev::timer tw;
		565	void receive_rep (dns_rcv *r);
		566
		567	dns_connection (connection *c);
		568	~dns_connection ();
		569	};
		570
		571	struct dns_snd
		572	{
		573	dns_packet *pkt;
		574	tstamp timeout, sent;
		575	int retry;
		576	struct dns_connection *dns;
		577	int seqno;
		578	bool stdhdr;
		579
		580	void gen_stream_req (int seqno, byte_stream &stream);
		581	void gen_syn_req ();
		582
		583	dns_snd (dns_connection *dns);
		584	~dns_snd ();
		585	};
		586
		587	dns_snd::dns_snd (dns_connection *dns)
		588	: dns (dns)
		589	{
		590	timeout = 0;
461	retry = 0;	591	retry = 0;
		592	seqno = 0;
		593	sent = ev::ev_now ();
		594	stdhdr = false;
462		595
463	pkt = new dns_packet;	596	pkt = new dns_packet;
464		597
465	pkt->id = next_id ();	598	pkt->id = next_id ();
466	}	599	}
467		600
		601	dns_snd::~dns_snd ()
		602	{
		603	delete pkt;
		604	}
		605
		606	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		607	{
		608	// add tunnel domain
		609	for (;;)
		610	{
		611	const char *end = strchr (domain, '.');
		612
		613	if (!end)
		614	end = domain + strlen (domain);
		615
		616	int len = end - domain;
		617
		618	pkt [offs++] = len;
		619	memcpy (pkt.at (offs), domain, len);
		620	offs += len;
		621
		622	if (!*end)
		623	break;
		624
		625	domain = end + 1;
		626	}
		627	}
		628
468	void dns_req::gen_stream_req (int seqno, byte_stream *stream)	629	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
469	{	630	{
		631	stdhdr = true;
470	this->seqno = seqno;	632	this->seqno = seqno;
		633
		634	timeout = ev::ev_now () + INITIAL_TIMEOUT;
471		635
472	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	636	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
473	pkt->qdcount = htons (1);	637	pkt->qdcount = htons (1);
474		638
475	int offs = 6*2;	639	int offs = 6*2;
476	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	640	int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
477	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	641	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
478	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra	642	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
479		643
480	char enc[256], *encp = enc;	644	char enc[256], *encp = enc;
481	encode_header (enc, THISNODE->id, seqno);	645	encode_header (enc, THISNODE->id, seqno);
482		646
483	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);	647	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
484		648
485	if (datalen > stream->size ())	649	if (datalen > stream.size ())
486	datalen = stream->size ();	650	datalen = stream.size ();
487		651
488	int enclen = cdc62.encode (enc + HDRSIZE, stream->begin (), datalen) + HDRSIZE;	652	int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
489
490	printf ("cdc62.encode %d->%d:%02x %02x %02x %02x\n", datalen, enclen,
491	stream->begin ()[0],
492	stream->begin ()[1],
493	stream->begin ()[2],
494	stream->begin ()[3]);
495
496	stream->remove (datalen);	653	stream.remove (datalen);
497		654
498	while (enclen)	655	while (enclen)
499	{	656	{
500	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;	657	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
501		658
…		…
506	encp += lbllen;	663	encp += lbllen;
507		664
508	enclen -= lbllen;	665	enclen -= lbllen;
509	}	666	}
510		667
511	const char *suffix = THISNODE->domain;	668	append_domain (*pkt, offs, dns->c->conf->domain);
512
513	// add tunnel domain
514	for (;;)
515	{
516	const char *end = strchr (suffix, '.');
517
518	if (!end)
519	end = suffix + strlen (suffix);
520
521	int len = end - suffix;
522
523	(*pkt)[offs++] = len;
524	memcpy (&((*pkt)[offs]), suffix, len);
525	offs += len;
526
527	if (!*end)
528	break;
529
530	suffix = end + 1;
531	}
532		669
533	(*pkt)[offs++] = 0;	670	(*pkt)[offs++] = 0;
534	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	671	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		672	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		673
		674	pkt->len = offs;
		675	}
		676
		677	void dns_snd::gen_syn_req ()
		678	{
		679	timeout = ev::ev_now () + INITIAL_SYN_TIMEOUT;
		680
		681	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		682	pkt->qdcount = htons (1);
		683
		684	int offs = 6 * 2;
		685
		686	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
		687
		688	assert (elen <= MAX_LBL_SIZE);
		689
		690	(*pkt)[offs] = elen;
		691	offs += elen + 1;
		692	append_domain (*pkt, offs, dns->c->conf->domain);
		693
		694	(*pkt)[offs++] = 0;
		695	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
535	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	696	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
536		697
537	pkt->len = offs;	698	pkt->len = offs;
538	}	699	}
539		700
…		…
558	{	719	{
559	delete pkt;	720	delete pkt;
560	}	721	}
561		722
562	/////////////////////////////////////////////////////////////////////////////	723	/////////////////////////////////////////////////////////////////////////////
563		724
564	struct dns_cfg	725	dns_connection::dns_connection (connection *c)
		726	: c (c)
		727	, rcvdq (MAX_BACKLOG * 2)
		728	, snddq (MAX_BACKLOG)
		729	, tw (this, &dns_connection::time_cb)
565	{	730	{
566	u8 id1, id2, id3;	731	vpn = c->vpn;
567	u8 def_ttl;
568	u8 unused1;
569	u16 max_size;
570	u8 flags1, flags2;
571	};
572		732
		733	established = false;
		734
		735	rcvseq = repseq = sndseq = 0;
		736
		737	last_sent = last_received = 0;
		738	poll_interval = 0.5; // starting here
		739	send_interval = 0.5; // starting rate
		740	min_latency = INITIAL_TIMEOUT;
		741	}
		742
		743	dns_connection::~dns_connection ()
		744	{
		745	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		746	i != rcvpq.end ();
		747	++i)
		748	delete *i;
		749	}
		750
573	void connection::dnsv4_receive_rep (struct dns_rcv *r)	751	void dns_connection::receive_rep (dns_rcv *r)
574	{	752	{
		753	if (r->datalen)
		754	{
		755	last_received = ev::ev_now ();
		756	tw ();
		757
		758	poll_interval = send_interval;
		759	}
		760	else
		761	{
		762	poll_interval *= 1.5;
		763
		764	if (poll_interval > MAX_POLL_INTERVAL)
		765	poll_interval = MAX_POLL_INTERVAL;
		766	}
		767
575	dns_rcvpq.push_back (r);	768	rcvpq.push_back (r);
576		769
577	printf ("%d got inketc %d (%02x %02x %02x %02x)\n", THISNODE->id, r->seqno
578	,r->data[0]
579	,r->data[1]
580	,r->data[2]
581	,r->data[3]
582	);
583	redo:	770	redo:
584		771
585	// find next packet	772	// find next packet
586	for (vector<dns_rcv *>::iterator i = dns_rcvpq.end (); i-- != dns_rcvpq.begin (); )	773	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
587	if (SEQNO_EQ (dns_rcvseq, (*i)->seqno))	774	if (SEQNO_EQ (rcvseq, (*i)->seqno))
588	{	775	{
		776	//printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
589	// enter the packet into our input stream	777	// enter the packet into our input stream
590	r = *i;	778	r = *i;
591		779
592	printf ("%d checking for older packet %d\n", THISNODE->id, dns_rcvseq);
593	// remove the oldest packet, look forward, as it's oldest first	780	// remove the oldest packet, look forward, as it's oldest first
594	for (vector<dns_rcv *>::iterator j = dns_rcvpq.begin (); j != dns_rcvpq.end (); ++j)	781	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
595	if (SEQNO_EQ ((*j)->seqno, dns_rcvseq - MAX_WINDOW))	782	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
596	{	783	{
597	printf ("%d removing %d\n", THISNODE->id, (*j)->seqno);	784	//printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
598	delete *j;	785	delete *j;
599	dns_rcvpq.erase (j);	786	rcvpq.erase (j);
600	break;	787	break;
601	}	788	}
602		789
603	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;	790	rcvseq = (rcvseq + 1) & SEQNO_MASK;
604		791
605	if (!dns_snddq && !dns_rcvdq)	792	if (!rcvdq.put (r->data, r->datalen))
606	{	793	{
607	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);	794	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
608	dns_snddq = new byte_stream (MAX_BACKLOG);	795	abort (); // MUST never overflow, can be caused by data corruption, TODO
609
610	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
611	}	796	}
612		797
613	if (!dns_rcvdq->put (r->data, r->datalen))
614	abort (); // MUST never overflow, can be caused by data corruption, TODO
615
616	while (vpn_packet *pkt = dns_rcvdq->get ())	798	while (vpn_packet *pkt = rcvdq.get ())
617	{	799	{
618	sockinfo si;	800	sockinfo si;
619	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	801	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
620		802
621	vpn->recv_vpn_packet (pkt, si);	803	vpn->recv_vpn_packet (pkt, si);
		804
		805	delete pkt;
622	}	806	}
623		807
624	// check for further packets	808	// check for further packets
625	goto redo;	809	goto redo;
626	}	810	}
627	}	811	}
628		812
629	dns_packet *	813	void
630	vpn::dnsv4_server (dns_packet *pkt)	814	vpn::dnsv4_server (dns_packet &pkt)
631	{	815	{
632	u16 flags = ntohs (pkt->flags);	816	u16 flags = ntohs (pkt.flags);
633		817
634	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
635	int offs = 6 * 2; // skip header	818	int offs = 6 * 2; // skip header
636		819
637	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	820	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
638		821
639	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	822	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
640	&& pkt->qdcount == htons (1))	823	&& pkt.qdcount == htons (1))
641	{	824	{
642	char qname[MAXSIZE];	825	char qname [MAXSIZE];
643	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	826	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
644		827
645	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	828	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
646	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	829	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
647		830
648	pkt->qdcount = htons (1);	831	pkt.qdcount = htons (1);
649	pkt->ancount = 0;	832	pkt.ancount = 0;
650	pkt->nscount = 0; // should be self, as other nameservers reply like this	833	pkt.nscount = 0; // should be self, as other nameservers reply like this
651	pkt->arcount = 0; // a record for self, as other nameservers reply like this	834	pkt.arcount = 0; // a record for self, as other nameservers reply like this
652		835
653	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	836	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
654		837
655	int dlen = strlen (THISNODE->domain);	838	int dlen = strlen (THISNODE->domain);
656		839
657	if (qclass == RR_CLASS_IN	840	if (qclass == RR_CLASS_IN
658	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
659	&& qlen > dlen + 1 + HDRSIZE	841	&& qlen > dlen + 1
660	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	842	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
661	{	843	{
662	// correct class, domain: parse	844	// now generate reply
663	int client, seqno;	845	pkt.ancount = htons (1); // one answer RR
664	decode_header (qname, client, seqno);	846	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
665		847
666	u8 data[MAXSIZE];	848	if ((qtype == RR_TYPE_ANY
667	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	849	\|\| qtype == RR_TYPE_TXT
668		850	\|\| qtype == RR_TYPE_NULL)
669	printf ("cdc62.decode %d(%d): %02x %02x %02x %02x\n",
670	qlen - (dlen + 1 + HDRSIZE), datalen	851	&& qlen > dlen + 1 + HDRSIZE)
671	,data[0]
672	,data[1]
673	,data[2]
674	,data[3]);
675
676	printf ("SRV got %d <%.*s>\n", seqno, qlen, qname + HDRSIZE);//D
677	printf ("SRV got %d <%.*s>\n", seqno, qlen - (dlen + 1 + HDRSIZE), qname + HDRSIZE);//D
678
679	if (0 < client && client <= conns.size ())
680	{	852	{
		853	// correct class, domain: parse
		854	int client, seqno;
		855	decode_header (qname, client, seqno);
		856
		857	u8 data[MAXSIZE];
		858	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
		859
		860	if (0 < client && client <= conns.size ())
		861	{
681	connection *c = conns [client - 1];	862	connection *c = conns [client - 1];
		863	dns_connection *dns = c->dns;
		864	dns_rcv *rcv;
682		865
		866	if (dns)
		867	{
683	for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.end (); i-- != c->dns_rcvpq.begin (); )	868	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
684	if (SEQNO_EQ ((*i)->seqno, seqno))	869	if (SEQNO_EQ ((*i)->seqno, seqno))
		870	{
		871	// already seen that request: simply reply with the cached reply
		872	dns_rcv r = i;
		873
		874	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		875
		876	// refresh header & id, as the retry count could have changed
		877	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		878	r->pkt->id = pkt.id;
		879
		880	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		881
		882	goto duplicate_request;
		883	}
		884
		885	// new packet, queue
		886	rcv = new dns_rcv (seqno, data, datalen);
		887	dns->receive_rep (rcv);
		888	}
		889
685	{	890	{
686	// already seen that request: simply reply with the cached reply	891	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
687	dns_rcv r = i;
688		892
689	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	893	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		894	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		895	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		896	pkt [offs++] = 0; pkt [offs++] = 0;
		897	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
690		898
691	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);	899	int rdlen_offs = offs += 2;
692	pkt->id = r->pkt->id;	900
693	goto duplicate_request;	901	if (dns)
		902	{
		903	int dlen = ntohs (dns->cfg.max_size) - offs;
		904
		905	// bind doesn't compress well, so reduce further by one label length
		906	dlen -= qlen;
		907
		908	// only put data into in-order sequence packets, if
		909	// we receive out-of-order packets we generate empty
		910	// replies
		911	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		912	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
		913	{
		914	dns->repseq = seqno;
		915
		916	while (dlen > 1 && !dns->snddq.empty ())
		917	{
		918	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		919
		920	if (txtlen > dns->snddq.size ())
		921	txtlen = dns->snddq.size ();
		922
		923	pkt[offs++] = txtlen;
		924	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
		925	offs += txtlen;
		926	dns->snddq.remove (txtlen);
		927
		928	dlen -= txtlen + 1;
		929	}
		930	}
		931
		932	// avoid completely empty TXT rdata
		933	if (offs == rdlen_offs)
		934	pkt[offs++] = 0;
		935
		936	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
		937	}
		938	else
		939	{
		940	// send RST
		941	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		942	pkt [offs++] = CMD_IP_RST;
		943	}
		944
		945	int rdlen = offs - rdlen_offs;
		946
		947	pkt [rdlen_offs - 2] = rdlen >> 8;
		948	pkt [rdlen_offs - 1] = rdlen;
		949
		950	if (dns)
		951	{
		952	// now update dns_rcv copy
		953	rcv->pkt->len = offs;
		954	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		955	}
694	}	956	}
695		957
696	// new packet, queue	958	duplicate_request: ;
697	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);	959	}
698	c->dnsv4_receive_rep (rcv);	960	else
699
700	// now generate reply
701	pkt->ancount = htons (1); // one answer RR
702	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	961	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		962	}
		963	else if (qtype == RR_TYPE_A
		964	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		965	{
		966	dns_cfg cfg;
		967	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		968	int client = ntohs (cfg.client);
703		969
704	(*pkt) [offs++] = 0xc0;
705	(pkt) [offs++] = 6 2; // same as in query section	970	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
706		971
707	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;	972	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
708	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;	973	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
709
710	(pkt) [offs++] = 0; (pkt) [offs++] = 0;	974	pkt [offs++] = 0; pkt [offs++] = 0;
711	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL	975	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		976	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
712		977
713	int dlen = MAX_PKT_SIZE - offs - 2;	978	slog (L_INFO, _("DNS: client %d connects"), client);
714		979
715	// bind doesn't compress well, so reduce further by one label length	980	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
716	dlen -= qlen;	981	pkt [offs++] = CMD_IP_REJ;
717		982
718	int rdlen_offs = offs += 2;	983	if (0 < client && client <= conns.size ())
719
720	while (c->dns_snddq
721	&& !c->dns_snddq->empty ()
722	&& dlen > 1)
723	{	984	{
724	int txtlen = dlen <= 255 ? dlen - 1 : 255;	985	connection *c = conns [client - 1];
725		986
726	if (txtlen > c->dns_snddq->size ())	987	if (cfg.valid ())
727	txtlen = c->dns_snddq->size ();	988	{
		989	pkt [offs - 1] = CMD_IP_SYN;
728		990
729	(*pkt)[offs++] = txtlen;	991	delete c->dns;
730	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);	992	c->dns = new dns_connection (c);
731	offs += txtlen;	993	c->dns->cfg = cfg;
732	c->dns_snddq->remove (txtlen);	994	}
733
734	dlen -= txtlen + 1;
735	}	995	}
736
737	// avoid empty TXT rdata
738	if (offs == rdlen_offs)
739	(*pkt)[offs++] = 0;
740
741	int rdlen = offs - rdlen_offs;
742
743	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
744	(*pkt) [rdlen_offs - 1] = rdlen;
745
746	// now update dns_rcv copy
747	rcv->pkt->len = offs;
748	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
749
750	duplicate_request: ;
751	}	996	}
752	else
753	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
754	}	997	}
755		998
756	pkt->len = offs;	999	pkt.len = offs;
757	}	1000	}
758
759	return pkt;
760	}	1001	}
761		1002
762	void	1003	void
763	vpn::dnsv4_client (dns_packet *pkt)	1004	vpn::dnsv4_client (dns_packet &pkt)
764	{	1005	{
765	u16 flags = ntohs (pkt->flags);	1006	u16 flags = ntohs (pkt.flags);
766	int offs = 6 * 2; // skip header	1007	int offs = 6 * 2; // skip header
767		1008
768	pkt->qdcount = ntohs (pkt->qdcount);	1009	pkt.qdcount = ntohs (pkt.qdcount);
769	pkt->ancount = ntohs (pkt->ancount);	1010	pkt.ancount = ntohs (pkt.ancount);
770		1011
771	// go through our request list and find the corresponding request	1012	// go through our request list and find the corresponding request
772	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	1013	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
773	i != dns_sndpq.end ();	1014	i != dns_sndpq.end ();
774	++i)	1015	++i)
775	if ((*i)->pkt->id == pkt->id)	1016	if ((*i)->pkt->id == pkt.id)
776	{	1017	{
		1018	dns_connection dns = (i)->dns;
777	connection c = (i)->conn;	1019	connection *c = dns->c;
778	int seqno = (*i)->seqno;	1020	int seqno = (*i)->seqno;
779	u8 data[MAXSIZE], *datap = data;	1021	u8 data[MAXSIZE], *datap = data;
		1022	//printf ("rcv pkt %x\n", seqno);//D
		1023
		1024	if ((*i)->retry)
		1025	{
		1026	dns->send_interval *= 1.01;
		1027	if (dns->send_interval > MAX_SEND_INTERVAL)
		1028	dns->send_interval = MAX_SEND_INTERVAL;
		1029	}
		1030	else
		1031	{
		1032	#if 0
		1033	dns->send_interval *= 0.999;
		1034	#endif
		1035	// the latency surely puts an upper bound on
		1036	// the minimum send interval
		1037	double latency = ev::ev_now () - (*i)->sent;
		1038
		1039	if (latency < dns->min_latency)
		1040	dns->min_latency = latency;
		1041
		1042	if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
		1043	dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
		1044
		1045	if (dns->send_interval < conf.dns_send_interval)
		1046	dns->send_interval = conf.dns_send_interval;
		1047	}
780		1048
781	delete *i;	1049	delete *i;
782	dns_sndpq.erase (i);	1050	dns_sndpq.erase (i);
783		1051
784	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	1052	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
785	{	1053	{
786	char qname[MAXSIZE];	1054	char qname[MAXSIZE];
787		1055
788	while (pkt->qdcount-- && offs < MAXSIZE - 4)	1056	while (pkt.qdcount-- && offs < MAXSIZE - 4)
789	{	1057	{
790	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1058	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
791	offs += 4; // skip qtype, qclass	1059	offs += 4; // skip qtype, qclass
792	}	1060	}
793		1061
794	while (pkt->ancount-- && offs < MAXSIZE - 10)	1062	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
795	{	1063	{
796	int qlen = //D
797	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1064	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
798		1065
799	printf ("got reply to <%.*s>\n", qlen, qname);//D
800
801	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1066	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
802	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1067	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
803	u32 ttl = (*pkt) [offs++] << 24;	1068	u32 ttl = pkt [offs++] << 24;
804	ttl \|= (*pkt) [offs++] << 16;	1069	ttl \|= pkt [offs++] << 16;
805	ttl \|= (*pkt) [offs++] << 8;	1070	ttl \|= pkt [offs++] << 8;
806	ttl \|= (*pkt) [offs++];	1071	ttl \|= pkt [offs++];
807
808	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1072	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
809		1073
810	if (rdlen <= MAXSIZE - offs)	1074	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
811	{	1075	{
812	// decode bytes, finally	1076	if (rdlen <= MAXSIZE - offs)
813
814	while (rdlen)
815	{	1077	{
		1078	// decode bytes, finally
		1079
		1080	while (rdlen)
		1081	{
816	int txtlen = (*pkt) [offs++];	1082	int txtlen = pkt [offs++];
817		1083
818	assert (txtlen + offs < MAXSIZE - 1);	1084	assert (txtlen + offs < MAXSIZE - 1);
819		1085
820	memcpy (datap, pkt->at (offs), txtlen);	1086	memcpy (datap, pkt.at (offs), txtlen);
821	datap += txtlen; offs += txtlen;	1087	datap += txtlen; offs += txtlen;
822		1088
823	rdlen -= txtlen + 1;	1089	rdlen -= txtlen + 1;
		1090	}
824	}	1091	}
825
826	}	1092	}
		1093	else if (qtype == RR_TYPE_A)
		1094	{
		1095	u8 ip [4];
827		1096
		1097	ip [0] = pkt [offs++];
		1098	ip [1] = pkt [offs++];
		1099	ip [2] = pkt [offs++];
		1100	ip [3] = pkt [offs++];
		1101
		1102	if (ip [0] == CMD_IP_1
		1103	&& ip [1] == CMD_IP_2
		1104	&& ip [2] == CMD_IP_3)
		1105	{
		1106	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
		1107
		1108	if (ip [3] == CMD_IP_RST)
		1109	{
		1110	slog (L_DEBUG, _("DNS: got tunnel RST request"));
		1111
		1112	delete dns; c->dns = 0;
		1113
		1114	return;
		1115	}
		1116	else if (ip [3] == CMD_IP_SYN)
		1117	{
		1118	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
		1119	dns->established = true;
		1120	}
		1121	else if (ip [3] == CMD_IP_REJ)
		1122	{
		1123	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1124	abort ();
		1125	}
		1126	else
		1127	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
		1128	}
		1129	else
		1130	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
		1131	ip [0], ip [1], ip [2], ip [3]);
		1132
		1133	return;
		1134	}
		1135
		1136	int client, rseqno;
		1137	decode_header (qname, client, rseqno);
		1138
		1139	if (client != THISNODE->id)
		1140	{
		1141	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
		1142	datap = 0;
		1143	}
		1144	else if (rseqno != seqno)
		1145	{
		1146	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
		1147	datap = 0;
		1148	}
828	}	1149	}
829	}	1150	}
830		1151
831	// todo: pkt now used	1152	// todo: pkt now used
		1153	if (datap)
832	c->dnsv4_receive_rep (new dns_rcv (seqno, data, datap - data));	1154	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
833		1155
834	break;	1156	break;
835	}	1157	}
836
837	delete pkt;
838	}	1158	}
839		1159
840	void	1160	void
841	vpn::dnsv4_ev (io_watcher &w, short revents)	1161	vpn::dnsv4_ev (ev::io &w, int revents)
842	{	1162	{
843	if (revents & EVENT_READ)	1163	if (revents & EV_READ)
844	{	1164	{
845	dns_packet *pkt = new dns_packet;	1165	dns_packet *pkt = new dns_packet;
846	struct sockaddr_in sa;	1166	struct sockaddr_in sa;
847	socklen_t sa_len = sizeof (sa);	1167	socklen_t sa_len = sizeof (sa);
848		1168
849	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1169	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
850		1170
851	if (pkt->len > 0)	1171	if (pkt->len > 0)
852	{	1172	{
853	if (pkt->flags & htons (FLAG_TC))	1173	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1174	dnsv4_client (*pkt);
		1175	else
854	{	1176	{
855	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));	1177	dnsv4_server (*pkt);
856	//TODO connection reset	1178	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
857	}	1179	}
858		1180
859	if (THISNODE->dns_port)	1181	delete pkt;
860	{
861	pkt = dnsv4_server (pkt);
862	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);
863	}
864	else
865	dnsv4_client (pkt);
866	}	1182	}
867	}	1183	}
868	}	1184	}
869		1185
870	bool	1186	bool
871	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1187	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
872	{	1188	{
873	// never initialized	1189	int client = ntohl (si.host);
874	if (!dns_snddq && !dns_rcvdq)
875	{
876	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
877	dns_snddq = new byte_stream (MAX_BACKLOG);
878		1190
879	//dns_rcvseq = dns_sndseq = 0;	1191	assert (0 < client && client <= conns.size ());
880		1192
881	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);	1193	connection *c = conns [client - 1];
882	}	1194
		1195	if (!c->dns)
		1196	c->dns = new dns_connection (c);
883		1197
884	if (!dns_snddq->put (pkt))	1198	if (c->dns->snddq.put (pkt))
885	return false;	1199	c->dns->tw ();
886		1200
887	// start timer if neccessary	1201	// always return true even if the buffer overflows
888	if (!THISNODE->dns_port && !dnsv4_tw.active)
889	dnsv4_cb (dnsv4_tw);
890
891	return true;	1202	return true;
892	}	1203	}
893		1204
894	void	1205	void
895	connection::dnsv4_cb (time_watcher &w)	1206	connection::dnsv4_reset_connection ()
896	{	1207	{
		1208	//delete dns; dns = 0; //TODO
		1209	}
		1210
		1211	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1212
		1213	void
		1214	dns_connection::time_cb (ev::timer &w, int revents)
		1215	{
		1216	// servers have to be polled
		1217	if (THISNODE->dns_port)
		1218	return;
		1219
897	// check for timeouts and (re)transmit	1220	// check for timeouts and (re)transmit
898	tstamp next = NOW + 60;	1221	tstamp next = ev::now () + poll_interval;
899	dns_req *send = 0;	1222	dns_snd *send = 0;
900		1223
901	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1224	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
902	i != vpn->dns_sndpq.end ();	1225	i != vpn->dns_sndpq.end ();
903	++i)	1226	++i)
904	{	1227	{
905	dns_req r = i;	1228	dns_snd r = i;
906		1229
907	if (r->next <= NOW)	1230	if (r->timeout <= ev::ev_now ())
908	{	1231	{
909	if (!send)	1232	if (!send)
910	{	1233	{
911	send = r;	1234	send = r;
912		1235
913	if (r->retry)//D
914	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
915	r->retry++;	1236	r->retry++;
916	r->next = NOW + r->retry;	1237	r->timeout = ev::ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
		1238	//printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev::ev_now ());//D
		1239
		1240	// the following code changes the query section a bit, forcing
		1241	// the forwarder to generate a new request
		1242	if (r->stdhdr)
		1243	encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
917	}	1244	}
918	}	1245	}
919		1246	else
920	if (r->next < next)	1247	NEXT (r->timeout);
921	next = r->next;
922	}	1248	}
923		1249
924	if (!send	1250	if (!send)
925	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)
926	{	1251	{
		1252	// generate a new packet, if wise
		1253
		1254	if (!established)
		1255	{
		1256	if (vpn->dns_sndpq.empty ())
		1257	{
927	send = new dns_req (this);	1258	send = new dns_snd (this);
		1259
		1260	cfg.reset (THISNODE->id);
		1261	send->gen_syn_req ();
		1262	}
		1263	}
		1264	else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
		1265	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1266	{
		1267	if (last_sent + send_interval <= ev::ev_now ())
		1268	{
		1269	//printf ("sending data request etc.\n"); //D
		1270	if (!snddq.empty () \|\| last_received + 1. > ev::ev_now ())
		1271	{
		1272	poll_interval = send_interval;
		1273	NEXT (ev::ev_now () + send_interval);
		1274	}
		1275
		1276	send = new dns_snd (this);
928	send->gen_stream_req (dns_sndseq, dns_snddq);	1277	send->gen_stream_req (sndseq, snddq);
		1278	send->timeout = ev::ev_now () + min_latency * conf.dns_timeout_factor;
		1279	//printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev::ev_now (), min_latency, conf.dns_timeout_factor);//D
		1280
		1281	sndseq = (sndseq + 1) & SEQNO_MASK;
		1282	}
		1283	else
		1284	NEXT (last_sent + send_interval);
		1285	}
		1286
		1287	if (send)
929	vpn->dns_sndpq.push_back (send);	1288	vpn->dns_sndpq.push_back (send);
930
931	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
932	}	1289	}
933
934	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
935		1290
936	if (send)	1291	if (send)
937	{	1292	{
938	dns_packet *pkt = send->pkt;	1293	last_sent = ev::ev_now ();
939		1294	sendto (vpn->dnsv4_fd,
940	next = min_next;	1295	send->pkt->at (0), send->pkt->len, 0,
941		1296	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
942	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0, dns_si.sav4 (), dns_si.salenv4 ());
943	}	1297	}
944	else if (next < min_next)
945	next = min_next;
946		1298
947	w.start (next);	1299	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1300	poll_interval, send_interval, next - ev::ev_now (),
		1301	vpn->dns_sndpq.size (), snddq.size (),
		1302	rcvpq.size ());
		1303
		1304	// TODO: no idea when this happens, but when next < ev::ev_now (), we have a problem
		1305	// doesn't seem to happen anymore
		1306	if (next < ev::ev_now () + 0.001)
		1307	next = ev::ev_now () + 0.1;
		1308
		1309	w.start (next - ev::ev_now ());
948	}	1310	}
949		1311
950	#endif	1312	#endif
951		1313

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs. Revision 1.42 by pcg, Sat Nov 10 05:14:22 2007 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs.
Revision 1.42 by pcg, Sat Nov 10 05:14:22 2007 UTC