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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.2 by pcg, Tue Mar 1 04:38:21 2005 UTC vs.
Revision 1.6 by pcg, Thu Mar 3 08:38:32 2005 UTC

…		…
39		39
40	#include "netcompat.h"	40	#include "netcompat.h"
41		41
42	#include "vpn.h"	42	#include "vpn.h"
43		43
44	#if ENABLE_HTTP_PROXY
45	# include "conf.h"
46	#endif
47
48	#define MIN_RETRY 1.	44	#define MIN_RETRY 1.
49	#define MAX_RETRY 60.	45	#define MAX_RETRY 60.
50		46
51	#define SERVER conf.dns_port	47	#define MAX_OUTSTANDING 40 // max. outstanding requests
		48	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING
		49	#define MAX_RATE 1000 // requests/s
		50	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE
		51
		52	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well
		53	// 240 leaves about 4 bytes of server reply data
		54	// every two request byte sless give room for one reply byte
		55
		56	// seqno has 12 bits, but the lower bit is always left as zero
		57	// as bind caches ttl=0 records and we have to generate
		58	// sequence numbers that always differ case-insensitively
		59	#define SEQNO_MASK 0x07ff
52		60
53	/*	61	/*
54		62
55	protocol, in shorthand :)	63	protocol, in shorthand :)
56		64
…		…
79	static const char encode_chars[64 + 1];	87	static const char encode_chars[64 + 1];
80	static s8 decode_chars[256];	88	static s8 decode_chars[256];
81		89
82	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }	90	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }
83	static int decode_len (int bytes) { return (bytes * 6) / 8; }	91	static int decode_len (int bytes) { return (bytes * 6) / 8; }
84	static void encode (char dst, u8 src, int len);	92	static int encode (char dst, u8 src, int len);
85	static void decode (u8 dst, char src, int len);	93	static int decode (u8 dst, char src, int len);
86		94
87	dns64 ();	95	dns64 ();
88	} dns64;	96	} dns64;
89		97
90	const char dns64::encode_chars[64 + 1] = "0123456789-abcdefghijklmnopqrstuvwxyz_ABCDEFGHIJKLMNOPQRSTUVWXYZ";	98	// the following sequence has been crafted to
		99	// a) look somewhat random
		100	// b) the even (and odd) indices never share the same character as upper/lowercase
		101	const char dns64::encode_chars[64 + 1] = "_-dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI";
91	s8 dns64::decode_chars[256];	102	s8 dns64::decode_chars[256];
92		103
93	dns64::dns64 ()	104	dns64::dns64 ()
94	{	105	{
95	for (int i = 0; i < 64; i++)	106	for (int i = 0; i < 64; i++)
96	decode_chars [encode_chars [i]] = i + 1;	107	decode_chars [encode_chars [i]] = i + 1;
97	}	108	}
98		109
99	void dns64::encode (char dst, u8 src, int len)	110	int dns64::encode (char dst, u8 src, int len)
100	{	111	{
101	// slow, but easy to debug	112	// slow, but easy to debug
		113	char *beg = dst;
102	unsigned int accum, bits = 0;	114	unsigned int accum, bits = 0;
103		115
104	while (len--)	116	while (len--)
105	{	117	{
106	accum <<= 8;	118	accum <<= 8;
…		…
114	}	126	}
115	}	127	}
116		128
117	if (bits)	129	if (bits)
118	*dst++ = encode_chars [(accum << (6 - bits)) & 63];	130	*dst++ = encode_chars [(accum << (6 - bits)) & 63];
119	}
120		131
		132	return dst - beg;
		133	}
		134
121	void dns64::decode (u8 dst, char src, int len)	135	int dns64::decode (u8 dst, char src, int len)
122	{	136	{
123	// slow, but easy to debug	137	// slow, but easy to debug
		138	u8 *beg = dst;
124	unsigned int accum, bits = 0;	139	unsigned int accum, bits = 0;
125		140
126	while (len--)	141	while (len--)
127	{	142	{
128	s8 chr = decode_chars [(u8)*src++];	143	s8 chr = decode_chars [(u8)*src++];
129		144
130
131	if (!chr)	145	if (!chr)
132	break;	146	continue;
133		147
134	accum <<= 6;	148	accum <<= 6;
135	accum \|= chr - 1;	149	accum \|= chr - 1;
136	bits += 6;	150	bits += 6;
137		151
…		…
139	{	153	{
140	*dst++ = accum >> (bits - 8);	154	*dst++ = accum >> (bits - 8);
141	bits -= 8;	155	bits -= 8;
142	}	156	}
143	}	157	}
		158
		159	return dst - beg;
144	}	160	}
		161
		162	/////////////////////////////////////////////////////////////////////////////
		163
		164	struct byte_stream
		165	{
		166	u8 *data;
		167	int maxsize;
		168	int fill;
		169
		170	byte_stream (int maxsize);
		171	~byte_stream ();
		172
		173	bool empty () { return !fill; }
		174	int size () { return fill; }
		175
		176	bool put (u8 *data, unsigned int datalen);
		177	bool put (vpn_packet *pkt);
		178	vpn_packet *get ();
		179
		180	u8 *begin () { return data; }
		181	void remove (int count);
		182	};
		183
		184	byte_stream::byte_stream (int maxsize)
		185	: maxsize (maxsize), fill (0)
		186	{
		187	data = new u8 [maxsize];
		188	}
		189
		190	byte_stream::~byte_stream ()
		191	{
		192	delete data;
		193	}
		194
		195	void byte_stream::remove (int count)
		196	{
		197	if (count > fill)
		198	abort ();
		199
		200	memmove (data, data + count, fill -= count);
		201	}
		202
		203	bool byte_stream::put (u8 *data, unsigned int datalen)
		204	{
		205	if (maxsize - fill < datalen)
		206	return false;
		207
		208	memcpy (this->data + fill, data, datalen); fill += datalen;
		209
		210	return true;
		211	}
		212
		213	bool byte_stream::put (vpn_packet *pkt)
		214	{
		215	if (maxsize - fill < pkt->len + 2)
		216	return false;
		217
		218	data [fill++] = pkt->len >> 8;
		219	data [fill++] = pkt->len;
		220
		221	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;
		222
		223	return true;
		224	}
		225
		226	vpn_packet *byte_stream::get ()
		227	{
		228	int len = (data [0] << 8) \| data [1];
		229
		230	if (len > MAXSIZE && fill >= 2)
		231	abort (); // TODO handle this gracefully, connection reset
		232
		233	if (fill < len + 2)
		234	return 0;
		235
		236	vpn_packet *pkt = new vpn_packet;
		237
		238	pkt->len = len;
		239	memcpy (&((*pkt)[0]), data + 2, len);
		240	remove (len + 2);
		241
		242	return pkt;
		243	}
		244
		245	/////////////////////////////////////////////////////////////////////////////
145		246
146	#define FLAG_QUERY ( 0 << 15)	247	#define FLAG_QUERY ( 0 << 15)
147	#define FLAG_RESPONSE ( 1 << 15)	248	#define FLAG_RESPONSE ( 1 << 15)
148	#define FLAG_OP_MASK (15 << 14)	249	#define FLAG_OP_MASK (15 << 14)
149	#define FLAG_OP_QUERY ( 0 << 11)	250	#define FLAG_OP_QUERY ( 0 << 11)
150	#define FLAG_AA ( 1 << 10)	251	#define FLAG_AA ( 1 << 10)
151	#define FLAG_TC ( 1 << 9)	252	#define FLAG_TC ( 1 << 9)
152	#define FLAG_RD ( 1 << 8)	253	#define FLAG_RD ( 1 << 8)
153	#define FLAG_RA ( 1 << 7)	254	#define FLAG_RA ( 1 << 7)
		255	#define FLAG_AUTH ( 1 << 5)
154	#define FLAG_RCODE_MASK (15 << 0)	256	#define FLAG_RCODE_MASK (15 << 0)
155	#define FLAG_RCODE_OK ( 0 << 0)	257	#define FLAG_RCODE_OK ( 0 << 0)
156	#define FLAG_RCODE_FORMERR ( 1 << 0)	258	#define FLAG_RCODE_FORMERR ( 1 << 0)
157	#define FLAG_RCODE_SERVFAIL ( 2 << 0)	259	#define FLAG_RCODE_SERVFAIL ( 2 << 0)
158	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)	260	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)
159	#define FLAG_RCODE_REFUSED ( 5 << 0)	261	#define FLAG_RCODE_REFUSED ( 5 << 0)
160		262
161	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	263	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
162	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD)	264	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
163		265
164	struct dns_packet : net_packet	266	struct dns_packet : net_packet
165	{	267	{
166	u16 id;	268	u16 id;
167	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	269	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
…		…
204	}	306	}
205		307
206	return data - orig;	308	return data - orig;
207	}	309	}
208		310
		311	/////////////////////////////////////////////////////////////////////////////
		312
		313	struct dns_req
		314	{
		315	dns_packet *pkt;
		316	tstamp next;
		317	int retry;
		318	connection *conn;
		319	int seqno;
		320
		321	dns_req (connection *c);
		322	void gen_stream_req (int seqno, byte_stream *stream);
		323	};
		324
		325	static u16 dns_id = 12098; // TODO: should be per-vpn
		326
		327	static u16 next_id ()
		328	{
		329	// the simplest lsfr with periodicity 65535 i could find
		330	dns_id = (dns_id << 1)
		331	\| (((dns_id >> 1)
		332	^ (dns_id >> 2)
		333	^ (dns_id >> 4)
		334	^ (dns_id >> 15)) & 1);
		335
		336	return dns_id;
		337	}
		338
		339	dns_req::dns_req (connection *c)
		340	: conn (c)
		341	{
		342	next = 0;
		343	retry = 0;
		344
		345	pkt = new dns_packet;
		346
		347	pkt->id = next_id ();
		348	}
		349
		350	void dns_req::gen_stream_req (int seqno, byte_stream *stream)
		351	{
		352	this->seqno = seqno;
		353
		354	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		355	pkt->qdcount = htons (1);
		356
		357	int offs = 6*2;
		358	int dlen = MAX_DOMAIN_SIZE - strlen (THISNODE->domain) - 2;
		359	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
		360	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
		361
		362	u8 data[256]; //TODO
		363
		364	data[0] = THISNODE->id; //TODO
		365	data[1] = seqno >> 7; //TODO
		366	data[2] = seqno << 1; //TODO
		367
		368	int datalen = dns64::decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE) - 3;
		369
		370	if (datalen > stream->size ())
		371	datalen = stream->size ();
		372
		373	char enc[256], *encp = enc;
		374
		375	memcpy (data + 3, stream->begin (), datalen);
		376	int enclen = dns64::encode (enc, data, datalen + 3);
		377	stream->remove (datalen);
		378
		379	while (enclen)
		380	{
		381	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
		382
		383	(*pkt)[offs++] = lbllen;
		384	memcpy (pkt->at (offs), encp, lbllen);
		385
		386	offs += lbllen;
		387	encp += lbllen;
		388
		389	enclen -= lbllen;
		390	}
		391
		392	const char *suffix = THISNODE->domain;
		393
		394	// add tunnel domain
		395	for (;;)
		396	{
		397	const char *end = strchr (suffix, '.');
		398
		399	if (!end)
		400	end = suffix + strlen (suffix);
		401
		402	int len = end - suffix;
		403
		404	(*pkt)[offs++] = len;
		405	memcpy (&((*pkt)[offs]), suffix, len);
		406	offs += len;
		407
		408	if (!*end)
		409	break;
		410
		411	suffix = end + 1;
		412	}
		413
		414	(*pkt)[offs++] = 0;
		415	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		416	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		417
		418	pkt->len = offs;
		419	}
		420
		421	struct dns_rcv
		422	{
		423	int seqno;
		424	dns_packet *pkt; // reply packet
		425	u8 data [MAXSIZE]; // actually part of the reply packet...
		426	int datalen;
		427
		428	dns_rcv (int seqno, u8 *data, int datalen);
		429	~dns_rcv ();
		430	};
		431
		432	dns_rcv::dns_rcv (int seqno, u8 *data, int datalen)
		433	: seqno (seqno), pkt (new dns_packet), datalen (datalen)
		434	{
		435	memcpy (this->data, data, datalen);
		436	}
		437
		438	dns_rcv::~dns_rcv ()
		439	{
		440	delete pkt;
		441	}
		442
		443	/////////////////////////////////////////////////////////////////////////////
		444
209	struct dns_cfg	445	struct dns_cfg
210	{	446	{
211	u8 id1, id2, id3;	447	u8 id1, id2, id3;
212	u8 def_ttl;	448	u8 def_ttl;
213	u8 unused1;	449	u8 unused1;
214	u16 max_size;	450	u16 max_size;
215	u8 flags1, flags2;	451	u8 flags1, flags2;
216	};	452	};
217		453
218	// reply to client-poll	454	void connection::dnsv4_receive_rep (struct dns_rcv *r)
219	void dnsv4_poll (dns_packet *pkt, int &offs)
220	{	455	{
221	int dlen = MAX_PKT_SIZE - offs - 2;	456	dns_rcvpq.push_back (r);
222		457
223	(*pkt) [offs++] = 0;	458	redo:
224	(*pkt) [offs++] = 5;
225	memcpy (&((*pkt)[offs]), "\01H\02\xff\x00", 5);
226	offs += 5;
227		459
228	pkt->ancount = htons (1);	460	for (vector<dns_rcv *>::iterator i = dns_rcvpq.begin ();
		461	i != dns_rcvpq.end ();
		462	++i)
		463	if (dns_rcvseq == (*i)->seqno)
		464	{
		465	dns_rcv r = i;
		466
		467	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;
		468
		469	if (!dns_snddq && !dns_rcvdq)
		470	{
		471	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
		472	dns_snddq = new byte_stream (MAX_BACKLOG);
		473
		474	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
		475	}
		476
		477	if (!dns_rcvdq->put (r->data, r->datalen))
		478	abort (); // MUST never overflow, can be caused by data corruption, TODO
		479
		480	while (vpn_packet *pkt = dns_rcvdq->get ())
		481	{
		482	sockinfo si;
		483	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;
		484
		485	vpn->recv_vpn_packet (pkt, si);
		486	}
		487	}
		488	else if ((u32)(i)->seqno - (u32)dns_rcvseq + MAX_WINDOW > MAX_WINDOW 2)
		489	{
		490	//D
		491	//abort();
		492	printf ("%d erasing %d (%d)\n", THISNODE->id, (u32)(*i)->seqno, dns_rcvseq);
		493	dns_rcvpq.erase (i);
		494	goto redo;
		495	}
		496	}
		497
		498	dns_packet *
		499	vpn::dnsv4_server (dns_packet *pkt)
		500	{
		501	u16 flags = ntohs (pkt->flags);
		502
		503	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
		504	int offs = 6 * 2; // skip header
		505
229	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	506	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
230		507
231	printf ("we have room for %d bytes\n", dlen);	508	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))
		509	&& pkt->qdcount == htons (1))
		510	{
		511	char qname[MAXSIZE];
		512	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
		513
		514	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];
		515	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];
		516
		517	pkt->qdcount = htons (1);
		518	pkt->ancount = 0;
		519	pkt->nscount = 0; // should be self, as other nameservers reply like this
		520	pkt->arcount = 0; // a record for self, as other nameservers reply like this
		521
		522	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);
		523
		524	int dlen = strlen (THISNODE->domain);
		525
		526	if (qclass == RR_CLASS_IN
		527	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
		528	&& qlen > dlen + 1
		529	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
		530	{
		531	// correct class, domain: parse
		532	u8 data[MAXSIZE];
		533	int datalen = dns64::decode (data, qname, qlen - dlen - 1);
		534
		535	int client = data[0];
		536	int seqno = ((data[1] << 7) \| (data[2] >> 1)) & SEQNO_MASK;
		537
		538	if (0 < client && client <= conns.size ())
		539	{
		540	connection *c = conns [client - 1];
		541
		542	redo:
		543
		544	for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.begin ();
		545	i != c->dns_rcvpq.end ();
		546	++i)
		547	if ((*i)->seqno == seqno)
		548	{
		549	// already seen that request: simply reply with the cached reply
		550	dns_rcv r = i;
		551
		552	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D
		553
		554	offs = r->pkt->len;
		555	memcpy (pkt->at (0), r->pkt->at (0), offs);
		556	goto duplicate_request;
		557	}
		558
		559	// new packet, queue
		560	dns_rcv *rcv = new dns_rcv (seqno, data + 3, datalen - 3);
		561	c->dnsv4_receive_rep (rcv);
		562
		563	// now generate reply
		564	pkt->ancount = htons (1); // one answer RR
		565	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
		566
		567	(*pkt) [offs++] = 0xc0;
		568	(pkt) [offs++] = 6 2; // same as in query section
		569
		570	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;
		571	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;
		572
		573	(pkt) [offs++] = 0; (pkt) [offs++] = 0;
		574	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL
		575
		576	int dlen = MAX_PKT_SIZE - offs - 2;
		577
		578	// bind doesn't compress well, so reduce further by one label length
		579	dlen -= qlen;
		580
		581	int rdlen_offs = offs += 2;
		582
		583	while (c->dns_snddq
		584	&& !c->dns_snddq->empty ()
		585	&& dlen > 1)
		586	{
		587	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		588
		589	if (txtlen > c->dns_snddq->size ())
		590	txtlen = c->dns_snddq->size ();
		591
		592	(*pkt)[offs++] = txtlen;
		593	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);
		594	offs += txtlen;
		595	c->dns_snddq->remove (txtlen);
		596
		597	dlen -= txtlen + 1;
		598	}
		599
		600	// avoid empty TXT rdata
		601	if (offs == rdlen_offs)
		602	(*pkt)[offs++] = 0;
		603
		604	int rdlen = offs - rdlen_offs;
		605
		606	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
		607	(*pkt) [rdlen_offs - 1] = rdlen;
		608
		609	// now update dns_rcv copy
		610	rcv->pkt->len = offs;
		611	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
		612
		613	duplicate_request: ;
		614	}
		615	else
		616	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		617	}
		618
		619	pkt->len = offs;
		620	}
		621
		622	return pkt;
		623	}
		624
		625	void
		626	vpn::dnsv4_client (dns_packet *pkt)
		627	{
		628	u16 flags = ntohs (pkt->flags);
		629	int offs = 6 * 2; // skip header
		630
		631	pkt->qdcount = ntohs (pkt->qdcount);
		632	pkt->ancount = ntohs (pkt->ancount);
		633
		634	// go through our request list and find the corresponding request
		635	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();
		636	i != dns_sndpq.end ();
		637	++i)
		638	if ((*i)->pkt->id == pkt->id)
		639	{
		640	connection c = (i)->conn;
		641	int seqno = (*i)->seqno;
		642	u8 data[MAXSIZE], *datap = data;
		643
		644	delete *i;
		645	dns_sndpq.erase (i);
		646
		647	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))
		648	{
		649	char qname[MAXSIZE];
		650
		651	while (pkt->qdcount-- && offs < MAXSIZE - 4)
		652	{
		653	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
		654	offs += 4; // skip qtype, qclass
		655	}
		656
		657	while (pkt->ancount-- && offs < MAXSIZE - 10)
		658	{
		659	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
		660
		661	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];
		662	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];
		663	u32 ttl = (*pkt) [offs++] << 24;
		664	ttl \|= (*pkt) [offs++] << 16;
		665	ttl \|= (*pkt) [offs++] << 8;
		666	ttl \|= (*pkt) [offs++];
		667
		668	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];
		669
		670	if (rdlen <= MAXSIZE - offs)
		671	{
		672	// decode bytes, finally
		673
		674	while (rdlen)
		675	{
		676	int txtlen = (*pkt) [offs++];
		677
		678	assert (txtlen + offs < MAXSIZE - 1);
		679
		680	memcpy (datap, pkt->at (offs), txtlen);
		681	datap += txtlen; offs += txtlen;
		682
		683	rdlen -= txtlen + 1;
		684	}
		685
		686	}
		687
		688	}
		689	}
		690
		691	// todo: pkt now used
		692	c->dnsv4_receive_rep (new dns_rcv (seqno, data, datap - data));
		693
		694	break;
		695	}
		696
		697	delete pkt;
232	}	698	}
233		699
234	void	700	void
235	vpn::dnsv4_ev (io_watcher &w, short revents)	701	vpn::dnsv4_ev (io_watcher &w, short revents)
236	{	702	{
…		…
238	{	704	{
239	dns_packet *pkt = new dns_packet;	705	dns_packet *pkt = new dns_packet;
240	struct sockaddr_in sa;	706	struct sockaddr_in sa;
241	socklen_t sa_len = sizeof (sa);	707	socklen_t sa_len = sizeof (sa);
242		708
243	int len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	709	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);
244	pkt->len = len;
245		710
246	u16 flags = ntohs (pkt->flags);	711	if (pkt->len > 0)
247
248	if (THISNODE->dns_port)
249	{	712	{
250	// server	713	if (pkt->flags & htons (FLAG_TC))
251	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
252
253	int offs = 6 * 2; // skip header
254
255	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))
256	&& pkt->qdcount == htons (1))
257	{	714	{
258	char qname[MAXSIZE];	715	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));
259	int qlen = pkt->decode_label ((char *)qname, MAXSIZE, offs);	716	//TODO connection reset
260
261	printf ("rcvd packet len %d, id%04x flags%04x q%04x a%04x n%04x a%04x <%s>\n", len,
262	pkt->id, flags, pkt->qdcount, pkt->ancount, pkt->nscount, pkt->arcount, qname);//D
263
264	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];
265	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];
266
267	pkt->qdcount = htons (1);
268	pkt->ancount = 0;
269	pkt->nscount = 0; // should be self, as other nameservers reply like this
270	pkt->arcount = 0; // a record for self, as other nameservers reply like this
271
272	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);
273
274	int dlen = strlen (THISNODE->domain);
275
276	if (qclass == RR_CLASS_IN
277	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
278	&& qlen > dlen + 1
279	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
280	{
281	// correct class, now generate reply
282	pkt->ancount = htons (1); // one answer RR
283
284	(*pkt) [offs++] = 0xc0;
285	(pkt) [offs++] = 6 2; // same as in query section
286
287	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;
288	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;
289
290	(pkt) [offs++] = 0; (pkt) [offs++] = 0;
291	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL
292
293	dnsv4_poll (pkt, offs);
294	printf ("correct class\n");
295	}
296	}	717	}
297		718
		719	if (THISNODE->dns_port)
		720	{
		721	pkt = dnsv4_server (pkt);
298	sendto (w.fd, &((pkt)[0]), offs, 0, (sockaddr )&sa, sa_len);	722	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);
		723	}
		724	else
		725	dnsv4_client (pkt);
299	}	726	}
300	else	727	}
		728	}
		729
		730	bool
		731	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
		732	{
		733	// never initialized
		734	if (!dns_snddq && !dns_rcvdq)
		735	{
		736	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
		737	dns_snddq = new byte_stream (MAX_BACKLOG);
		738
		739	//dns_rcvseq = dns_sndseq = 0;
		740
		741	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
		742	}
		743
		744	if (!dns_snddq->put (pkt))
		745	return false;
		746
		747	// start timer if neccessary
		748	if (!THISNODE->dns_port && !dnsv4_tw.active)
		749	dnsv4_cb (dnsv4_tw);
		750
		751	return true;
		752	}
		753
		754	void
		755	connection::dnsv4_cb (time_watcher &w)
		756	{
		757	// check for timeouts and (re)transmit
		758	tstamp next = NOW + 60;
		759	dns_req *send = 0;
		760
		761	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();
		762	i != vpn->dns_sndpq.end ();
		763	++i)
		764	{
		765	dns_req r = i;
		766
		767	if (r->next <= NOW)
301	{	768	{
302	// client	769	if (!send)
		770	{
		771	send = r;
		772
		773	if (r->retry)//D
		774	printf ("req %d, retry %d\n", r->pkt->id, r->retry);
		775	r->retry++;
		776	r->next = NOW + r->retry;
		777	}
303	}	778	}
		779
		780	if (r->next < next)
		781	next = r->next;
		782	}
		783
		784	if (!send
		785	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)
304	}	786	{
305	}	787	send = new dns_req (this);
		788	send->gen_stream_req (dns_sndseq, dns_snddq);
		789	vpn->dns_sndpq.push_back (send);
306		790
307	bool	791	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
308	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	792	}
309	{	793
310	//return i->send_packet (pkt, tos);	794	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
		795
		796	if (send)
		797	{
		798	dns_packet *pkt = send->pkt;
		799
		800	next = min_next;
		801
		802	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0, dns_si.sav4 (), dns_si.salenv4 ());
		803	}
		804	else if (next < min_next)
		805	next = min_next;
		806
		807	w.start (next);
311	}	808	}
312		809
313	#endif	810	#endif
314		811

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.2 by pcg, Tue Mar 1 04:38:21 2005 UTC vs. Revision 1.6 by pcg, Thu Mar 3 08:38:32 2005 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.2 by pcg, Tue Mar 1 04:38:21 2005 UTC vs.
Revision 1.6 by pcg, Thu Mar 3 08:38:32 2005 UTC