[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 1.7 by pcg, Thu Mar 3 16:54:34 2005 UTC

…		…
1	/*	1	/*
2	vpn_dns.C -- handle the dns tunnel part of the protocol.	2	vpn_dns.C -- handle the dns tunnel part of the protocol.
3	Copyright (C) 2003-2004 Marc Lehmann <pcg@goof.com>	3	Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de>
4		4
		5	This file is part of GVPE.
		6
5	This program is free software; you can redistribute it and/or modify	7	GVPE is free software; you can redistribute it and/or modify
6	it under the terms of the GNU General Public License as published by	8	it under the terms of the GNU General Public License as published by
7	the Free Software Foundation; either version 2 of the License, or	9	the Free Software Foundation; either version 2 of the License, or
8	(at your option) any later version.	10	(at your option) any later version.
9		11
10	This program is distributed in the hope that it will be useful,	12	This program is distributed in the hope that it will be useful,
11	but WITHOUT ANY WARRANTY; without even the implied warranty of	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13	GNU General Public License for more details.	15	GNU General Public License for more details.
14		16
15	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
16	along with this program; if not, write to the Free Software	18	along with gvpe; if not, write to the Free Software
17	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA	19	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18	*/	20	*/
19		21
20	#include "config.h"	22	#include "config.h"
21		23
39		41
40	#include "netcompat.h"	42	#include "netcompat.h"
41		43
42	#include "vpn.h"	44	#include "vpn.h"
43		45
44	#if ENABLE_HTTP_PROXY
45	# include "conf.h"
46	#endif
47
48	#define MIN_RETRY 1.	46	#define MIN_RETRY 1.
49	#define MAX_RETRY 60.	47	#define MAX_RETRY 60.
50		48
51	#define SERVER conf.dns_port	49	#define MAX_OUTSTANDING 40 // max. outstanding requests
		50	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING
		51	#define MAX_RATE 1000 // requests/s
		52	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE
		53
		54	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well
		55	// 240 leaves about 4 bytes of server reply data
		56	// every two request byte sless give room for one reply byte
		57
		58	// seqno has 12 bits, but the lower bit is always left as zero
		59	// as bind caches ttl=0 records and we have to generate
		60	// sequence numbers that always differ case-insensitively
		61	#define SEQNO_MASK 0x07ff
52		62
53	/*	63	/*
54		64
55	protocol, in shorthand :)	65	protocol, in shorthand :)
56		66
…		…
79	static const char encode_chars[64 + 1];	89	static const char encode_chars[64 + 1];
80	static s8 decode_chars[256];	90	static s8 decode_chars[256];
81		91
82	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }	92	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }
83	static int decode_len (int bytes) { return (bytes * 6) / 8; }	93	static int decode_len (int bytes) { return (bytes * 6) / 8; }
84	static void encode (char dst, u8 src, int len);	94	static int encode (char dst, u8 src, int len);
85	static void decode (u8 dst, char src, int len);	95	static int decode (u8 dst, char src, int len);
86		96
87	dns64 ();	97	dns64 ();
88	} dns64;	98	} dns64;
89		99
90	const char dns64::encode_chars[64 + 1] = "0123456789-abcdefghijklmnopqrstuvwxyz_ABCDEFGHIJKLMNOPQRSTUVWXYZ";	100	// the following sequence has been crafted to
		101	// a) look somewhat random
		102	// b) the even (and odd) indices never share the same character as upper/lowercase
		103	const char dns64::encode_chars[64 + 1] = "_-dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI";
91	s8 dns64::decode_chars[256];	104	s8 dns64::decode_chars[256];
92		105
93	dns64::dns64 ()	106	dns64::dns64 ()
94	{	107	{
95	for (int i = 0; i < 64; i++)	108	for (int i = 0; i < 64; i++)
96	decode_chars [encode_chars [i]] = i + 1;	109	decode_chars [encode_chars [i]] = i + 1;
97	}	110	}
98		111
99	void dns64::encode (char dst, u8 src, int len)	112	int dns64::encode (char dst, u8 src, int len)
100	{	113	{
101	// slow, but easy to debug	114	// slow, but easy to debug
		115	char *beg = dst;
102	unsigned int accum, bits = 0;	116	unsigned int accum, bits = 0;
103		117
104	while (len--)	118	while (len--)
105	{	119	{
106	accum <<= 8;	120	accum <<= 8;
…		…
114	}	128	}
115	}	129	}
116		130
117	if (bits)	131	if (bits)
118	*dst++ = encode_chars [(accum << (6 - bits)) & 63];	132	*dst++ = encode_chars [(accum << (6 - bits)) & 63];
119	}
120		133
		134	return dst - beg;
		135	}
		136
121	void dns64::decode (u8 dst, char src, int len)	137	int dns64::decode (u8 dst, char src, int len)
122	{	138	{
123	// slow, but easy to debug	139	// slow, but easy to debug
		140	u8 *beg = dst;
124	unsigned int accum, bits = 0;	141	unsigned int accum, bits = 0;
125		142
126	while (len--)	143	while (len--)
127	{	144	{
128	s8 chr = decode_chars [(u8)*src++];	145	s8 chr = decode_chars [(u8)*src++];
129		146
130
131	if (!chr)	147	if (!chr)
132	break;	148	continue;
133		149
134	accum <<= 6;	150	accum <<= 6;
135	accum \|= chr - 1;	151	accum \|= chr - 1;
136	bits += 6;	152	bits += 6;
137		153
…		…
139	{	155	{
140	*dst++ = accum >> (bits - 8);	156	*dst++ = accum >> (bits - 8);
141	bits -= 8;	157	bits -= 8;
142	}	158	}
143	}	159	}
		160
		161	return dst - beg;
144	}	162	}
		163
		164	/////////////////////////////////////////////////////////////////////////////
		165
		166	struct byte_stream
		167	{
		168	u8 *data;
		169	int maxsize;
		170	int fill;
		171
		172	byte_stream (int maxsize);
		173	~byte_stream ();
		174
		175	bool empty () { return !fill; }
		176	int size () { return fill; }
		177
		178	bool put (u8 *data, unsigned int datalen);
		179	bool put (vpn_packet *pkt);
		180	vpn_packet *get ();
		181
		182	u8 *begin () { return data; }
		183	void remove (int count);
		184	};
		185
		186	byte_stream::byte_stream (int maxsize)
		187	: maxsize (maxsize), fill (0)
		188	{
		189	data = new u8 [maxsize];
		190	}
		191
		192	byte_stream::~byte_stream ()
		193	{
		194	delete data;
		195	}
		196
		197	void byte_stream::remove (int count)
		198	{
		199	if (count > fill)
		200	abort ();
		201
		202	memmove (data, data + count, fill -= count);
		203	}
		204
		205	bool byte_stream::put (u8 *data, unsigned int datalen)
		206	{
		207	if (maxsize - fill < datalen)
		208	return false;
		209
		210	memcpy (this->data + fill, data, datalen); fill += datalen;
		211
		212	return true;
		213	}
		214
		215	bool byte_stream::put (vpn_packet *pkt)
		216	{
		217	if (maxsize - fill < pkt->len + 2)
		218	return false;
		219
		220	data [fill++] = pkt->len >> 8;
		221	data [fill++] = pkt->len;
		222
		223	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;
		224
		225	return true;
		226	}
		227
		228	vpn_packet *byte_stream::get ()
		229	{
		230	int len = (data [0] << 8) \| data [1];
		231
		232	if (len > MAXSIZE && fill >= 2)
		233	abort (); // TODO handle this gracefully, connection reset
		234
		235	if (fill < len + 2)
		236	return 0;
		237
		238	vpn_packet *pkt = new vpn_packet;
		239
		240	pkt->len = len;
		241	memcpy (&((*pkt)[0]), data + 2, len);
		242	remove (len + 2);
		243
		244	return pkt;
		245	}
		246
		247	/////////////////////////////////////////////////////////////////////////////
145		248
146	#define FLAG_QUERY ( 0 << 15)	249	#define FLAG_QUERY ( 0 << 15)
147	#define FLAG_RESPONSE ( 1 << 15)	250	#define FLAG_RESPONSE ( 1 << 15)
148	#define FLAG_OP_MASK (15 << 14)	251	#define FLAG_OP_MASK (15 << 14)
149	#define FLAG_OP_QUERY ( 0 << 11)	252	#define FLAG_OP_QUERY ( 0 << 11)
150	#define FLAG_AA ( 1 << 10)	253	#define FLAG_AA ( 1 << 10)
151	#define FLAG_TC ( 1 << 9)	254	#define FLAG_TC ( 1 << 9)
152	#define FLAG_RD ( 1 << 8)	255	#define FLAG_RD ( 1 << 8)
153	#define FLAG_RA ( 1 << 7)	256	#define FLAG_RA ( 1 << 7)
		257	#define FLAG_AUTH ( 1 << 5)
154	#define FLAG_RCODE_MASK (15 << 0)	258	#define FLAG_RCODE_MASK (15 << 0)
155	#define FLAG_RCODE_OK ( 0 << 0)	259	#define FLAG_RCODE_OK ( 0 << 0)
156	#define FLAG_RCODE_FORMERR ( 1 << 0)	260	#define FLAG_RCODE_FORMERR ( 1 << 0)
157	#define FLAG_RCODE_SERVFAIL ( 2 << 0)	261	#define FLAG_RCODE_SERVFAIL ( 2 << 0)
158	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)	262	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)
159	#define FLAG_RCODE_REFUSED ( 5 << 0)	263	#define FLAG_RCODE_REFUSED ( 5 << 0)
160		264
161	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	265	#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)	266	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
163		267
164	struct dns_packet : net_packet	268	struct dns_packet : net_packet
165	{	269	{
166	u16 id;	270	u16 id;
167	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	271	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
…		…
204	}	308	}
205		309
206	return data - orig;	310	return data - orig;
207	}	311	}
208		312
		313	/////////////////////////////////////////////////////////////////////////////
		314
		315	struct dns_req
		316	{
		317	dns_packet *pkt;
		318	tstamp next;
		319	int retry;
		320	connection *conn;
		321	int seqno;
		322
		323	dns_req (connection *c);
		324	void gen_stream_req (int seqno, byte_stream *stream);
		325	};
		326
		327	static u16 dns_id = 12098; // TODO: should be per-vpn
		328
		329	static u16 next_id ()
		330	{
		331	// the simplest lsfr with periodicity 65535 i could find
		332	dns_id = (dns_id << 1)
		333	\| (((dns_id >> 1)
		334	^ (dns_id >> 2)
		335	^ (dns_id >> 4)
		336	^ (dns_id >> 15)) & 1);
		337
		338	return dns_id;
		339	}
		340
		341	dns_req::dns_req (connection *c)
		342	: conn (c)
		343	{
		344	next = 0;
		345	retry = 0;
		346
		347	pkt = new dns_packet;
		348
		349	pkt->id = next_id ();
		350	}
		351
		352	void dns_req::gen_stream_req (int seqno, byte_stream *stream)
		353	{
		354	this->seqno = seqno;
		355
		356	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		357	pkt->qdcount = htons (1);
		358
		359	int offs = 6*2;
		360	int dlen = MAX_DOMAIN_SIZE - strlen (THISNODE->domain) - 2;
		361	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
		362	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
		363
		364	u8 data[256]; //TODO
		365
		366	data[0] = THISNODE->id; //TODO
		367	data[1] = seqno >> 7; //TODO
		368	data[2] = seqno << 1; //TODO
		369
		370	int datalen = dns64::decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE) - 3;
		371
		372	if (datalen > stream->size ())
		373	datalen = stream->size ();
		374
		375	char enc[256], *encp = enc;
		376
		377	memcpy (data + 3, stream->begin (), datalen);
		378	int enclen = dns64::encode (enc, data, datalen + 3);
		379	stream->remove (datalen);
		380
		381	while (enclen)
		382	{
		383	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
		384
		385	(*pkt)[offs++] = lbllen;
		386	memcpy (pkt->at (offs), encp, lbllen);
		387
		388	offs += lbllen;
		389	encp += lbllen;
		390
		391	enclen -= lbllen;
		392	}
		393
		394	const char *suffix = THISNODE->domain;
		395
		396	// add tunnel domain
		397	for (;;)
		398	{
		399	const char *end = strchr (suffix, '.');
		400
		401	if (!end)
		402	end = suffix + strlen (suffix);
		403
		404	int len = end - suffix;
		405
		406	(*pkt)[offs++] = len;
		407	memcpy (&((*pkt)[offs]), suffix, len);
		408	offs += len;
		409
		410	if (!*end)
		411	break;
		412
		413	suffix = end + 1;
		414	}
		415
		416	(*pkt)[offs++] = 0;
		417	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		418	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		419
		420	pkt->len = offs;
		421	}
		422
		423	struct dns_rcv
		424	{
		425	int seqno;
		426	dns_packet *pkt; // reply packet
		427	u8 data [MAXSIZE]; // actually part of the reply packet...
		428	int datalen;
		429
		430	dns_rcv (int seqno, u8 *data, int datalen);
		431	~dns_rcv ();
		432	};
		433
		434	dns_rcv::dns_rcv (int seqno, u8 *data, int datalen)
		435	: seqno (seqno), pkt (new dns_packet), datalen (datalen)
		436	{
		437	memcpy (this->data, data, datalen);
		438	}
		439
		440	dns_rcv::~dns_rcv ()
		441	{
		442	delete pkt;
		443	}
		444
		445	/////////////////////////////////////////////////////////////////////////////
		446
209	struct dns_cfg	447	struct dns_cfg
210	{	448	{
211	u8 id1, id2, id3;	449	u8 id1, id2, id3;
212	u8 def_ttl;	450	u8 def_ttl;
213	u8 unused1;	451	u8 unused1;
214	u16 max_size;	452	u16 max_size;
215	u8 flags1, flags2;	453	u8 flags1, flags2;
216	};	454	};
217		455
218	// reply to client-poll	456	void connection::dnsv4_receive_rep (struct dns_rcv *r)
219	void dnsv4_poll (dns_packet *pkt, int &offs)
220	{	457	{
221	int dlen = MAX_PKT_SIZE - offs - 2;	458	dns_rcvpq.push_back (r);
222		459
223	(*pkt) [offs++] = 0;	460	redo:
224	(*pkt) [offs++] = 5;
225	memcpy (&((*pkt)[offs]), "\01H\02\xff\x00", 5);
226	offs += 5;
227		461
228	pkt->ancount = htons (1);	462	for (vector<dns_rcv *>::iterator i = dns_rcvpq.begin ();
		463	i != dns_rcvpq.end ();
		464	++i)
		465	if (dns_rcvseq == (*i)->seqno)
		466	{
		467	dns_rcv r = i;
		468
		469	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;
		470
		471	if (!dns_snddq && !dns_rcvdq)
		472	{
		473	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
		474	dns_snddq = new byte_stream (MAX_BACKLOG);
		475
		476	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
		477	}
		478
		479	if (!dns_rcvdq->put (r->data, r->datalen))
		480	abort (); // MUST never overflow, can be caused by data corruption, TODO
		481
		482	while (vpn_packet *pkt = dns_rcvdq->get ())
		483	{
		484	sockinfo si;
		485	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;
		486
		487	vpn->recv_vpn_packet (pkt, si);
		488	}
		489	}
		490	else if ((u32)(i)->seqno - (u32)dns_rcvseq + MAX_WINDOW > MAX_WINDOW 2)
		491	{
		492	//D
		493	//abort();
		494	printf ("%d erasing %d (%d)\n", THISNODE->id, (u32)(*i)->seqno, dns_rcvseq);
		495	dns_rcvpq.erase (i);
		496	goto redo;
		497	}
		498	}
		499
		500	dns_packet *
		501	vpn::dnsv4_server (dns_packet *pkt)
		502	{
		503	u16 flags = ntohs (pkt->flags);
		504
		505	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
		506	int offs = 6 * 2; // skip header
		507
229	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	508	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
230		509
231	printf ("we have room for %d bytes\n", dlen);	510	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))
		511	&& pkt->qdcount == htons (1))
		512	{
		513	char qname[MAXSIZE];
		514	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
		515
		516	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];
		517	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];
		518
		519	pkt->qdcount = htons (1);
		520	pkt->ancount = 0;
		521	pkt->nscount = 0; // should be self, as other nameservers reply like this
		522	pkt->arcount = 0; // a record for self, as other nameservers reply like this
		523
		524	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);
		525
		526	int dlen = strlen (THISNODE->domain);
		527
		528	if (qclass == RR_CLASS_IN
		529	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
		530	&& qlen > dlen + 1
		531	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
		532	{
		533	// correct class, domain: parse
		534	u8 data[MAXSIZE];
		535	int datalen = dns64::decode (data, qname, qlen - dlen - 1);
		536
		537	int client = data[0];
		538	int seqno = ((data[1] << 7) \| (data[2] >> 1)) & SEQNO_MASK;
		539
		540	if (0 < client && client <= conns.size ())
		541	{
		542	connection *c = conns [client - 1];
		543
		544	redo:
		545
		546	for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.begin ();
		547	i != c->dns_rcvpq.end ();
		548	++i)
		549	if ((*i)->seqno == seqno)
		550	{
		551	// already seen that request: simply reply with the cached reply
		552	dns_rcv r = i;
		553
		554	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D
		555
		556	offs = r->pkt->len;
		557	memcpy (pkt->at (0), r->pkt->at (0), offs);
		558	goto duplicate_request;
		559	}
		560
		561	// new packet, queue
		562	dns_rcv *rcv = new dns_rcv (seqno, data + 3, datalen - 3);
		563	c->dnsv4_receive_rep (rcv);
		564
		565	// now generate reply
		566	pkt->ancount = htons (1); // one answer RR
		567	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
		568
		569	(*pkt) [offs++] = 0xc0;
		570	(pkt) [offs++] = 6 2; // same as in query section
		571
		572	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;
		573	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;
		574
		575	(pkt) [offs++] = 0; (pkt) [offs++] = 0;
		576	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL
		577
		578	int dlen = MAX_PKT_SIZE - offs - 2;
		579
		580	// bind doesn't compress well, so reduce further by one label length
		581	dlen -= qlen;
		582
		583	int rdlen_offs = offs += 2;
		584
		585	while (c->dns_snddq
		586	&& !c->dns_snddq->empty ()
		587	&& dlen > 1)
		588	{
		589	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		590
		591	if (txtlen > c->dns_snddq->size ())
		592	txtlen = c->dns_snddq->size ();
		593
		594	(*pkt)[offs++] = txtlen;
		595	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);
		596	offs += txtlen;
		597	c->dns_snddq->remove (txtlen);
		598
		599	dlen -= txtlen + 1;
		600	}
		601
		602	// avoid empty TXT rdata
		603	if (offs == rdlen_offs)
		604	(*pkt)[offs++] = 0;
		605
		606	int rdlen = offs - rdlen_offs;
		607
		608	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
		609	(*pkt) [rdlen_offs - 1] = rdlen;
		610
		611	// now update dns_rcv copy
		612	rcv->pkt->len = offs;
		613	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
		614
		615	duplicate_request: ;
		616	}
		617	else
		618	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		619	}
		620
		621	pkt->len = offs;
		622	}
		623
		624	return pkt;
		625	}
		626
		627	void
		628	vpn::dnsv4_client (dns_packet *pkt)
		629	{
		630	u16 flags = ntohs (pkt->flags);
		631	int offs = 6 * 2; // skip header
		632
		633	pkt->qdcount = ntohs (pkt->qdcount);
		634	pkt->ancount = ntohs (pkt->ancount);
		635
		636	// go through our request list and find the corresponding request
		637	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();
		638	i != dns_sndpq.end ();
		639	++i)
		640	if ((*i)->pkt->id == pkt->id)
		641	{
		642	connection c = (i)->conn;
		643	int seqno = (*i)->seqno;
		644	u8 data[MAXSIZE], *datap = data;
		645
		646	delete *i;
		647	dns_sndpq.erase (i);
		648
		649	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))
		650	{
		651	char qname[MAXSIZE];
		652
		653	while (pkt->qdcount-- && offs < MAXSIZE - 4)
		654	{
		655	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
		656	offs += 4; // skip qtype, qclass
		657	}
		658
		659	while (pkt->ancount-- && offs < MAXSIZE - 10)
		660	{
		661	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
		662
		663	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];
		664	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];
		665	u32 ttl = (*pkt) [offs++] << 24;
		666	ttl \|= (*pkt) [offs++] << 16;
		667	ttl \|= (*pkt) [offs++] << 8;
		668	ttl \|= (*pkt) [offs++];
		669
		670	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];
		671
		672	if (rdlen <= MAXSIZE - offs)
		673	{
		674	// decode bytes, finally
		675
		676	while (rdlen)
		677	{
		678	int txtlen = (*pkt) [offs++];
		679
		680	assert (txtlen + offs < MAXSIZE - 1);
		681
		682	memcpy (datap, pkt->at (offs), txtlen);
		683	datap += txtlen; offs += txtlen;
		684
		685	rdlen -= txtlen + 1;
		686	}
		687
		688	}
		689
		690	}
		691	}
		692
		693	// todo: pkt now used
		694	c->dnsv4_receive_rep (new dns_rcv (seqno, data, datap - data));
		695
		696	break;
		697	}
		698
		699	delete pkt;
232	}	700	}
233		701
234	void	702	void
235	vpn::dnsv4_ev (io_watcher &w, short revents)	703	vpn::dnsv4_ev (io_watcher &w, short revents)
236	{	704	{
…		…
238	{	706	{
239	dns_packet *pkt = new dns_packet;	707	dns_packet *pkt = new dns_packet;
240	struct sockaddr_in sa;	708	struct sockaddr_in sa;
241	socklen_t sa_len = sizeof (sa);	709	socklen_t sa_len = sizeof (sa);
242		710
243	int len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	711	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);
244	pkt->len = len;
245		712
246	u16 flags = ntohs (pkt->flags);	713	if (pkt->len > 0)
247
248	if (THISNODE->dns_port)
249	{	714	{
250	// server	715	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	{	716	{
258	char qname[MAXSIZE];	717	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));
259	int qlen = pkt->decode_label ((char *)qname, MAXSIZE, offs);	718	//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	}	719	}
297		720
		721	if (THISNODE->dns_port)
		722	{
		723	pkt = dnsv4_server (pkt);
298	sendto (w.fd, &((pkt)[0]), offs, 0, (sockaddr )&sa, sa_len);	724	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);
		725	}
		726	else
		727	dnsv4_client (pkt);
299	}	728	}
300	else	729	}
		730	}
		731
		732	bool
		733	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
		734	{
		735	// never initialized
		736	if (!dns_snddq && !dns_rcvdq)
		737	{
		738	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
		739	dns_snddq = new byte_stream (MAX_BACKLOG);
		740
		741	//dns_rcvseq = dns_sndseq = 0;
		742
		743	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
		744	}
		745
		746	if (!dns_snddq->put (pkt))
		747	return false;
		748
		749	// start timer if neccessary
		750	if (!THISNODE->dns_port && !dnsv4_tw.active)
		751	dnsv4_cb (dnsv4_tw);
		752
		753	return true;
		754	}
		755
		756	void
		757	connection::dnsv4_cb (time_watcher &w)
		758	{
		759	// check for timeouts and (re)transmit
		760	tstamp next = NOW + 60;
		761	dns_req *send = 0;
		762
		763	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();
		764	i != vpn->dns_sndpq.end ();
		765	++i)
		766	{
		767	dns_req r = i;
		768
		769	if (r->next <= NOW)
301	{	770	{
302	// client	771	if (!send)
		772	{
		773	send = r;
		774
		775	if (r->retry)//D
		776	printf ("req %d, retry %d\n", r->pkt->id, r->retry);
		777	r->retry++;
		778	r->next = NOW + r->retry;
		779	}
303	}	780	}
		781
		782	if (r->next < next)
		783	next = r->next;
		784	}
		785
		786	if (!send
		787	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)
304	}	788	{
305	}	789	send = new dns_req (this);
		790	send->gen_stream_req (dns_sndseq, dns_snddq);
		791	vpn->dns_sndpq.push_back (send);
306		792
307	bool	793	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
308	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	794	}
309	{	795
310	//return i->send_packet (pkt, tos);	796	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
		797
		798	if (send)
		799	{
		800	dns_packet *pkt = send->pkt;
		801
		802	next = min_next;
		803
		804	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0, dns_si.sav4 (), dns_si.salenv4 ());
		805	}
		806	else if (next < min_next)
		807	next = min_next;
		808
		809	w.start (next);
311	}	810	}
312		811
313	#endif	812	#endif
314		813

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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 1.7 by pcg, Thu Mar 3 16:54:34 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 1.7 by pcg, Thu Mar 3 16:54:34 2005 UTC