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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.4 by pcg, Wed Mar 2 05:49:31 2005 UTC vs.
Revision 1.9 by pcg, Fri Mar 4 04:52:38 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
35	#include <unistd.h>	37	#include <unistd.h>
36	#include <fcntl.h>	38	#include <fcntl.h>
37		39
38	#include <map>	40	#include <map>
39		41
		42	#include <gmp.h>
		43
40	#include "netcompat.h"	44	#include "netcompat.h"
41		45
42	#include "vpn.h"	46	#include "vpn.h"
43		47
44	#define MIN_RETRY 1.	48	#define MIN_RETRY 1.
45	#define MAX_RETRY 60.	49	#define MAX_RETRY 6.
46		50
47	#define MAX_OUTSTANDING 10 // max. outstanding requests	51	#define MAX_OUTSTANDING 400 // max. outstanding requests
48	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING	52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING
49	#define MAX_RATE 1 // requests/s	53	#define MAX_RATE 100 // requests/s
50	#define MAX_BACKLOG (10*1024) // size of protocol backlog	54	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE
51		55
52	/*	56	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well
		57	// 240 leaves about 4 bytes of server reply data
		58	// every two request byte sless give room for one reply byte
53		59
54	protocol, in shorthand :)	60	#define SEQNO_MASK 0xffff
55		61	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
56	client -> server <req> ANY?
57	server -> client <req> TXT <rep>
58
59	<req> is dns64-encoded <client-id:12><recv-seqno:10>[<send-seqno:10><data>]
60	<rep> is dns64-encoded <0:12><recv-seqno:10>[<send-seqno:10><data>]
61
62	if <client-id> is zero, the connection will be configured:
63
64	<0:12><0:4>client-id:12><default-ttl:8><max-size:16><flags:16>
65
66	*/
67		62
68	#define MAX_LBL_SIZE 63	63	#define MAX_LBL_SIZE 63
69	#define MAX_PKT_SIZE 512	64	#define MAX_PKT_SIZE 512
70		65
71	#define RR_TYPE_TXT 16	66	#define RR_TYPE_TXT 16
72	#define RR_TYPE_ANY 255	67	#define RR_TYPE_ANY 255
73	#define RR_CLASS_IN 1	68	#define RR_CLASS_IN 1
74		69
		70	// works for cmaps up to 255 (not 256!)
		71	struct charmap
		72	{
		73	enum { INVALID = (u8)255 };
		74
		75	char encode [256]; // index => char
		76	u8 decode [256]; // char => index
		77	unsigned int size;
		78
		79	charmap (const char *cmap);
		80	};
		81
		82	charmap::charmap (const char *cmap)
		83	{
		84	char *enc = encode;
		85	u8 *dec = decode;
		86
		87	memset (enc, (char) 0, 256);
		88	memset (dec, (char)INVALID, 256);
		89
		90	for (size = 0; cmap [size]; size++)
		91	{
		92	enc [size] = cmap [size];
		93	dec [(u8)enc [size]] = size;
		94	}
		95
		96	assert (size < 256);
		97	}
		98
		99	#define MAX_DEC_LEN 500
		100	#define MAX_ENC_LEN (MAX_DEC_LEN * 2)
		101	#define MAX_LIMBS ((MAX_DEC_LEN * 8 + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS)
		102
		103	// ugly. minimum base is 16(!)
		104	struct basecoder
		105	{
		106	charmap cmap;
		107	unsigned int enc_len [MAX_DEC_LEN];
		108	unsigned int dec_len [MAX_ENC_LEN];
		109
		110	unsigned int encode_len (unsigned int len);
		111	unsigned int decode_len (unsigned int len);
		112
		113	unsigned int encode (char dst, u8 src, unsigned int len);
		114	unsigned int decode (u8 dst, char src, unsigned int len);
		115
		116	basecoder (const char *cmap);
		117	};
		118
		119	basecoder::basecoder (const char *cmap)
		120	: cmap (cmap)
		121	{
		122	for (unsigned int len = 0; len < MAX_DEC_LEN; ++len)
		123	{
		124	u8 src [MAX_DEC_LEN];
		125	u8 dst [MAX_ENC_LEN];
		126
		127	memset (src, 255, len);
		128
		129	mp_limb_t m [MAX_LIMBS];
		130	mp_size_t n;
		131
		132	n = mpn_set_str (m, src, len, 256);
		133	n = mpn_get_str (dst, this->cmap.size, m, n);
		134
		135	for (int i = 0; !dst [i]; ++i)
		136	n--;
		137
		138	enc_len [len] = n;
		139	dec_len [n] = len;
		140	}
		141	}
		142
		143	unsigned int basecoder::encode_len (unsigned int len)
		144	{
		145	return enc_len [len];
		146	}
		147
		148	unsigned int basecoder::decode_len (unsigned int len)
		149	{
		150	while (len && !dec_len [len])
		151	--len;
		152
		153	return dec_len [len];
		154	}
		155
		156	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
		157	{
		158	if (!len)
		159	return 0;
		160
		161	int elen = encode_len (len);
		162
		163	mp_limb_t m [MAX_LIMBS];
		164	mp_size_t n;
		165
		166	u8 dst_ [MAX_ENC_LEN];
		167
		168	n = mpn_set_str (m, src, len, 256);
		169	n = mpn_get_str (dst_, cmap.size, m, n);
		170
		171	int plen = elen; // for padding
		172
		173	while (n < plen)
		174	{
		175	*dst++ = cmap.encode [0];
		176	plen--;
		177	}
		178
		179	for (unsigned int i = n - plen; i < n; ++i)
		180	*dst++ = cmap.encode [dst_ [i]];
		181
		182	return elen;
		183	}
		184
		185	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
		186	{
		187	if (!len)
		188	return 0;
		189
		190	u8 src_ [MAX_ENC_LEN];
		191	unsigned int elen = 0;
		192
		193	while (len--)
		194	{
		195	u8 val = cmap.decode [(u8)*src++];
		196
		197	if (val != charmap::INVALID)
		198	src_ [elen++] = val;
		199	}
		200
		201	int dlen = decode_len (elen);
		202
		203	mp_limb_t m [MAX_LIMBS];
		204	mp_size_t n;
		205
		206	u8 dst_ [MAX_DEC_LEN];
		207
		208	n = mpn_set_str (m, src_, elen, cmap.size);
		209	n = mpn_get_str (dst_, 256, m, n);
		210
		211	if (n < dlen)
		212	{
		213	memset (dst, 0, dlen - n);
		214	memcpy (dst + dlen - n, dst_, n);
		215	}
		216	else
		217	memcpy (dst, dst_ + n - dlen, dlen);
		218
		219	return dlen;
		220	}
		221
		222	#if 0
		223	struct test { test (); } test;
		224
		225	test::test ()
		226	{
		227	basecoder cdc ("0123456789abcdefghijklmnopqrstuvwxyz");
		228
		229	u8 in[] = "0123456789abcdefghijklmnopqrstuvwxyz";
		230	static char enc[200];
		231	static u8 dec[200];
		232
		233	for (int i = 1; i < 20; i++)
		234	{
		235	int elen = cdc.encode (enc, in, i);
		236	int dlen = cdc.decode (dec, enc, elen);
		237
		238	printf ("%d>%d>%d (%s>%s)\n", i, elen, dlen, enc, dec);
		239	}
		240	abort ();
		241	}
		242	#endif
		243
		244	// the following sequence has been crafted to
		245	// a) look somewhat random
		246	// b) the even (and odd) indices never share the same character as upper/lowercase
75	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)	247	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)
76	struct dns64	248	// the other sequences are obviously derived
77	{	249	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
78	static const char encode_chars[64 + 1];	250	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
79	static s8 decode_chars[256];	251	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
		252	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
80		253
81	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }	254	/////////////////////////////////////////////////////////////////////////////
82	static int decode_len (int bytes) { return (bytes * 6) / 8; }
83	static int encode (char dst, u8 src, int len);
84	static int decode (u8 dst, char src, int len);
85		255
86	dns64 ();	256	#define HDRSIZE 6
87	} dns64;
88		257
89	const char dns64::encode_chars[64 + 1] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-";	258	inline void encode_header (char *data, int clientid, int seqno)
90	s8 dns64::decode_chars[256];
91
92	dns64::dns64 ()
93	{	259	{
94	for (int i = 0; i < 64; i++)	260	u8 hdr[3] = { clientid, seqno >> 8, seqno };
95	decode_chars [encode_chars [i]] = i + 1;
96	}
97		261
98	int dns64::encode (char dst, u8 src, int len)	262	assert (clientid < 256);
99	{
100	// slow, but easy to debug
101	char *beg = dst;
102	unsigned int accum, bits = 0;
103		263
104	while (len--)	264	cdc26.encode (data, hdr, 3);
105	{
106	accum <<= 8;
107	accum \|= *src++;
108	bits += 8;
109
110	while (bits >= 6)
111	{
112	*dst++ = encode_chars [(accum >> (bits - 6)) & 63];
113	bits -= 6;
114	}
115	}
116
117	if (bits)
118	*dst++ = encode_chars [(accum << (6 - bits)) & 63];
119
120	return dst - beg;
121	}	265	}
122		266
123	int dns64::decode (u8 dst, char src, int len)	267	inline void decode_header (char *data, int &clientid, int &seqno)
124	{	268	{
125	// slow, but easy to debug	269	u8 hdr[3];
126	u8 *beg = dst;
127	unsigned int accum, bits = 0;
128		270
129	while (len--)	271	cdc26.decode (hdr, data, HDRSIZE);
130	{
131	s8 chr = decode_chars [(u8)*src++];
132		272
133	if (!chr)	273	clientid = hdr[0];
134	break;	274	seqno = (hdr[1] << 8) \| hdr[2];
135
136	accum <<= 6;
137	accum \|= chr - 1;
138	bits += 6;
139
140	while (bits >= 8)
141	{
142	*dst++ = accum >> (bits - 8);
143	bits -= 8;
144	}
145	}
146
147	return dst - beg;
148	}	275	}
149		276
150	/////////////////////////////////////////////////////////////////////////////	277	/////////////////////////////////////////////////////////////////////////////
151		278
152	struct byte_stream	279	struct byte_stream
…		…
159	~byte_stream ();	286	~byte_stream ();
160		287
161	bool empty () { return !fill; }	288	bool empty () { return !fill; }
162	int size () { return fill; }	289	int size () { return fill; }
163		290
		291	bool put (u8 *data, unsigned int datalen);
164	bool put (vpn_packet *pkt);	292	bool put (vpn_packet *pkt);
165	vpn_packet *get ();	293	vpn_packet *get ();
166		294
167	u8 *begin () { return data; }	295	u8 *begin () { return data; }
168	void remove (int count);	296	void remove (int count);
…		…
185	abort ();	313	abort ();
186		314
187	memmove (data, data + count, fill -= count);	315	memmove (data, data + count, fill -= count);
188	}	316	}
189		317
		318	bool byte_stream::put (u8 *data, unsigned int datalen)
		319	{
		320	if (maxsize - fill < datalen)
		321	return false;
		322
		323	memcpy (this->data + fill, data, datalen); fill += datalen;
		324
		325	return true;
		326	}
		327
190	bool byte_stream::put (vpn_packet *pkt)	328	bool byte_stream::put (vpn_packet *pkt)
191	{	329	{
192	if (maxsize - fill < pkt->len + 2)	330	if (maxsize - fill < pkt->len + 2)
193	return false;	331	return false;
194		332
…		…
202		340
203	vpn_packet *byte_stream::get ()	341	vpn_packet *byte_stream::get ()
204	{	342	{
205	int len = (data [0] << 8) \| data [1];	343	int len = (data [0] << 8) \| data [1];
206		344
		345	if (len > MAXSIZE && fill >= 2)
		346	abort (); // TODO handle this gracefully, connection reset
		347
207	if (fill < len + 2)	348	if (fill < len + 2)
208	return 0;	349	return 0;
209		350
210	vpn_packet *pkt = new vpn_packet;	351	vpn_packet *pkt = new vpn_packet;
		352
		353	pkt->len = len;
211	memcpy (&((*pkt)[0]), data + 2, len);	354	memcpy (&((*pkt)[0]), data + 2, len);
212	remove (len + 2);	355	remove (len + 2);
213		356
214	return pkt;	357	return pkt;
215	}	358	}
216		359
217	/////////////////////////////////////////////////////////////////////////////	360	/////////////////////////////////////////////////////////////////////////////
218		361
219	#define FLAG_QUERY ( 0 << 15)	362	#define FLAG_QUERY ( 0 << 15)
220	#define FLAG_RESPONSE ( 1 << 15)	363	#define FLAG_RESPONSE ( 1 << 15)
221	#define FLAG_OP_MASK (15 << 14)	364	#define FLAG_OP_MASK (15 << 11)
222	#define FLAG_OP_QUERY ( 0 << 11)	365	#define FLAG_OP_QUERY ( 0 << 11)
223	#define FLAG_AA ( 1 << 10)	366	#define FLAG_AA ( 1 << 10)
224	#define FLAG_TC ( 1 << 9)	367	#define FLAG_TC ( 1 << 9)
225	#define FLAG_RD ( 1 << 8)	368	#define FLAG_RD ( 1 << 8)
226	#define FLAG_RA ( 1 << 7)	369	#define FLAG_RA ( 1 << 7)
		370	#define FLAG_AUTH ( 1 << 5)
227	#define FLAG_RCODE_MASK (15 << 0)	371	#define FLAG_RCODE_MASK (15 << 0)
228	#define FLAG_RCODE_OK ( 0 << 0)	372	#define FLAG_RCODE_OK ( 0 << 0)
229	#define FLAG_RCODE_FORMERR ( 1 << 0)	373	#define FLAG_RCODE_FORMERR ( 1 << 0)
230	#define FLAG_RCODE_SERVFAIL ( 2 << 0)	374	#define FLAG_RCODE_SERVFAIL ( 2 << 0)
231	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)	375	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)
232	#define FLAG_RCODE_REFUSED ( 5 << 0)	376	#define FLAG_RCODE_REFUSED ( 5 << 0)
233		377
234	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	378	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
235	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD)	379	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
236		380
237	struct dns_packet : net_packet	381	struct dns_packet : net_packet
238	{	382	{
239	u16 id;	383	u16 id;
240	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	384	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
…		…
284	struct dns_req	428	struct dns_req
285	{	429	{
286	dns_packet *pkt;	430	dns_packet *pkt;
287	tstamp next;	431	tstamp next;
288	int retry;	432	int retry;
289	connection *conn;	433	struct dns_connection *dns;
		434	int seqno;
290		435
291	dns_req (connection c, int seqno, byte_stream stream);	436	dns_req (dns_connection *dns);
		437	void gen_stream_req (int seqno, byte_stream &stream);
292	};	438	};
293		439
294	struct dns_rep
295	{
296	};
297
298	static u16 dns_id; // TODO: should be per-vpn	440	static u16 dns_id = 12098; // TODO: should be per-vpn
299		441
300	dns_req::dns_req (connection c, int seqno, byte_stream stream)	442	static u16 next_id ()
301	: conn (c)	443	{
		444	// the simplest lsfr with periodicity 65535 i could find
		445	dns_id = (dns_id << 1)
		446	\| (((dns_id >> 1)
		447	^ (dns_id >> 2)
		448	^ (dns_id >> 4)
		449	^ (dns_id >> 15)) & 1);
		450
		451	return dns_id;
		452	}
		453
		454	dns_req::dns_req (dns_connection *dns)
		455	: dns (dns)
302	{	456	{
303	next = 0;	457	next = 0;
304	retry = 0;	458	retry = 0;
305		459
306	pkt = new dns_packet;	460	pkt = new dns_packet;
307		461
308	pkt->id = dns_id++;	462	pkt->id = next_id ();
		463	}
		464
		465	void dns_req::gen_stream_req (int seqno, byte_stream &stream)
		466	{
		467	this->seqno = seqno;
		468
309	pkt->flags = DEFAULT_CLIENT_FLAGS;	469	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
310	pkt->qdcount = htons (1);	470	pkt->qdcount = htons (1);
311	pkt->ancount = 0;
312	pkt->nscount = 0;
313	pkt->arcount = 0;
314		471
315	int offs = 6*2;	472	int offs = 6*2;
316	int dlen = 255 - strlen (THISNODE->domain) - 1; // here we always have room for the max. label length	473	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);
		474	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
		475	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
317		476
318	u8 lbl[64]; //D	477	char enc[256], *encp = enc;
319	char enc[65];	478	encode_header (enc, THISNODE->id, seqno);
320	int lbllen = 3;
321	lbl[0] = c->conf->id; //D
322	lbl[1] = seqno >> 8; //D
323	lbl[2] = seqno; //D
324		479
325	while (dlen > 0)	480	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
326	{
327	int sndlen = dlen;
328		481
329	if (sndlen + lbllen > dns64::decode_len (MAX_LBL_SIZE))
330	sndlen = dns64::decode_len (MAX_LBL_SIZE) - lbllen;
331
332	if (sndlen > stream->size ())	482	if (datalen > stream.size ())
333	sndlen = stream->size ();	483	datalen = stream.size ();
334		484
335	if (sndlen + lbllen == 0)	485	int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
336	break;
337
338	memcpy (lbl + lbllen, stream->begin (), sndlen);
339	stream->remove (sndlen);	486	stream.remove (datalen);
340	lbllen += sndlen;
341		487
342	dns64::encode (enc, lbl, lbllen);	488	while (enclen)
		489	{
		490	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
343		491
344	int elen = dns64::encode_len (lbllen);
345	(*pkt)[offs++] = elen;	492	(*pkt)[offs++] = lbllen;
346	memcpy (&((*pkt)[offs]), enc, elen);	493	memcpy (pkt->at (offs), encp, lbllen);
		494
347	offs += elen;	495	offs += lbllen;
348	dlen -= elen + 1;	496	encp += lbllen;
349		497
350	lbllen = 0;	498	enclen -= lbllen;
351	}	499	}
352		500
353	const char *suffix = THISNODE->domain;	501	const char *suffix = THISNODE->domain;
354		502
355	// add tunnel domain	503	// add tunnel domain
…		…
375	(*pkt)[offs++] = 0;	523	(*pkt)[offs++] = 0;
376	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	524	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
377	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	525	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
378		526
379	pkt->len = offs;	527	pkt->len = offs;
		528	}
380		529
381	c->vpn->dns_sndpq.push_back (this);	530	struct dns_rcv
		531	{
		532	int seqno;
		533	dns_packet *pkt; // reply packet
		534	u8 data [MAXSIZE]; // actually part of the reply packet...
		535	int datalen;
		536
		537	dns_rcv (int seqno, u8 *data, int datalen);
		538	~dns_rcv ();
		539	};
		540
		541	dns_rcv::dns_rcv (int seqno, u8 *data, int datalen)
		542	: seqno (seqno), pkt (new dns_packet), datalen (datalen)
		543	{
		544	memcpy (this->data, data, datalen);
		545	}
		546
		547	dns_rcv::~dns_rcv ()
		548	{
		549	delete pkt;
382	}	550	}
383		551
384	/////////////////////////////////////////////////////////////////////////////	552	/////////////////////////////////////////////////////////////////////////////
		553
		554	struct dns_connection
		555	{
		556	connection *c;
		557	struct vpn *vpn;
		558
		559	vector<dns_rcv *> rcvpq;
		560
		561	int rcvseq;
		562	int sndseq;
		563
		564	byte_stream rcvdq;
		565	byte_stream snddq;
		566
		567	void time_cb (time_watcher &w); time_watcher tw;
		568	void receive_rep (dns_rcv *r);
		569
		570	dns_connection (connection *c);
		571	~dns_connection ();
		572	};
		573
		574	dns_connection::dns_connection (connection *c)
		575	: c (c)
		576	, rcvdq (MAX_BACKLOG * 2)
		577	, snddq (MAX_BACKLOG * 2)
		578	, tw (this, &dns_connection::time_cb)
		579	{
		580	vpn = c->vpn;
		581
		582	rcvseq = sndseq = 0;
		583	}
		584
		585	dns_connection::~dns_connection ()
		586	{
		587	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		588	i != rcvpq.end ();
		589	++i)
		590	delete *i;
		591	}
385		592
386	struct dns_cfg	593	struct dns_cfg
387	{	594	{
388	u8 id1, id2, id3;	595	u8 id1, id2, id3;
389	u8 def_ttl;	596	u8 def_ttl;
390	u8 unused1;	597	u8 unused1;
391	u16 max_size;	598	u16 max_size;
392	u8 flags1, flags2;	599	u8 flags1, flags2;
393	};	600	};
394		601
		602	void dns_connection::receive_rep (dns_rcv *r)
		603	{
		604	rcvpq.push_back (r);
		605
		606	redo:
		607
		608	// find next packet
		609	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
		610	if (SEQNO_EQ (rcvseq, (*i)->seqno))
		611	{
		612	// enter the packet into our input stream
		613	r = *i;
		614
		615	// remove the oldest packet, look forward, as it's oldest first
		616	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
		617	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
		618	{
		619	delete *j;
		620	rcvpq.erase (j);
		621	break;
		622	}
		623
		624	rcvseq = (rcvseq + 1) & SEQNO_MASK;
		625
		626	if (!rcvdq.put (r->data, r->datalen))
		627	abort (); // MUST never overflow, can be caused by data corruption, TODO
		628
		629	while (vpn_packet *pkt = rcvdq.get ())
		630	{
		631	sockinfo si;
		632	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;
		633
		634	vpn->recv_vpn_packet (pkt, si);
		635	}
		636
		637	// check for further packets
		638	goto redo;
		639	}
		640	}
		641
395	dns_packet *	642	dns_packet *
396	vpn::dnsv4_server (dns_packet *pkt)	643	vpn::dnsv4_server (dns_packet *pkt)
397	{	644	{
398	u16 flags = ntohs (pkt->flags);	645	u16 flags = ntohs (pkt->flags);
399		646
400	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);	647	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
401	int offs = 6 * 2; // skip header	648	int offs = 6 * 2; // skip header
402		649
403	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	650	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
404		651
405	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	652	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))
406	&& pkt->qdcount == htons (1))	653	&& pkt->qdcount == htons (1))
407	{	654	{
408	char qname[MAXSIZE];	655	char qname[MAXSIZE];
409	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	656	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
410
411	printf ("rcvd packet len %d, id%04x flags%04x q%04x a%04x n%04x a%04x <%s>\n", pkt->len,
412	pkt->id, flags, pkt->qdcount, pkt->ancount, pkt->nscount, pkt->arcount, qname);//D
413		657
414	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	658	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];
415	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	659	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];
416		660
417	pkt->qdcount = htons (1);	661	pkt->qdcount = htons (1);
…		…
423		667
424	int dlen = strlen (THISNODE->domain);	668	int dlen = strlen (THISNODE->domain);
425		669
426	if (qclass == RR_CLASS_IN	670	if (qclass == RR_CLASS_IN
427	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)	671	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
428	&& qlen > dlen + 1	672	&& qlen > dlen + 1 + HDRSIZE
429	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	673	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
430	{	674	{
431	// correct class, domain, parse	675	// correct class, domain: parse
		676	int client, seqno;
		677	decode_header (qname, client, seqno);
		678
432	u8 data[MAXSIZE];	679	u8 data[MAXSIZE];
433	int datalen = dns64::decode (data, qname, qlen - dlen - 1);	680	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
434		681
435	for (int i = 0; i < datalen; i++)	682	if (0 < client && client <= conns.size ())
436	printf ("%02x ", data[i]);
437	printf ("\n");
438
439
440
441
442	#if 0
443	// now generate reply
444	rep->ancount = htons (1); // one answer RR
445	rep->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
446
447	(*rep) [offs++] = 0xc0;
448	(rep) [offs++] = 6 2; // same as in query section
449
450	(rep) [offs++] = RR_TYPE_TXT >> 8; (rep) [offs++] = RR_TYPE_TXT;
451	(rep) [offs++] = RR_CLASS_IN >> 8; (rep) [offs++] = RR_CLASS_IN;
452
453	(rep) [offs++] = 0; (rep) [offs++] = 0;
454	(rep) [offs++] = 0; (rep) [offs++] = 0; // TTL
455
456	int dlen = MAX_PKT_SIZE - offs - 2;
457
458	printf ("we have room for %d bytes\n", dlen);
459
460	int rdlen_offs = offs += 2;
461
462	u8 txt[255];
463	txt[0] = 0;
464	txt[1] = 0;
465
466	int txtlen = 2;
467
468	while (dlen > 1)
469	{	683	{
470	int sndlen = --dlen;	684	connection *c = conns [client - 1];
471		685
472	if (sndlen + txtlen > 255)	686	if (!c->dns)
473	sndlen = 255 - txtlen;	687	c->dns = new dns_connection (c);
474		688
		689	dns_connection *dns = c->dns;
		690
		691	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
		692	if (SEQNO_EQ ((*i)->seqno, seqno))
		693	{
		694	// already seen that request: simply reply with the cached reply
		695	dns_rcv r = i;
		696
		697	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D
		698
		699	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);
		700	pkt->id = r->pkt->id;
		701	goto duplicate_request;
		702	}
		703
		704	// new packet, queue
		705	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);
		706	dns->receive_rep (rcv);
		707
		708	// now generate reply
		709	pkt->ancount = htons (1); // one answer RR
		710	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
		711
		712	(*pkt) [offs++] = 0xc0;
		713	(pkt) [offs++] = 6 2; // same as in query section
		714
		715	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;
		716	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;
		717
		718	(pkt) [offs++] = 0; (pkt) [offs++] = 0;
		719	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL
		720
		721	int dlen = MAX_PKT_SIZE - offs - 2;
		722
		723	// bind doesn't compress well, so reduce further by one label length
475	sndlen = 0;	724	dlen -= qlen;
476		725
		726	int rdlen_offs = offs += 2;
		727
		728	while (dlen > 1 && !dns->snddq.empty ())
		729	{
		730	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		731
		732	if (txtlen > dns->snddq.size ())
		733	txtlen = dns->snddq.size ();
		734
477	(*rep)[offs++] = sndlen + txtlen;	735	(*pkt)[offs++] = txtlen;
478	memcpy (&((*rep)[offs]), txt, txtlen);	736	memcpy (pkt->at (offs), dns->snddq.begin (), txtlen);
479	offs += txtlen;	737	offs += txtlen;
		738	dns->snddq.remove (txtlen);
480		739
481	//if (sndlen + txtlen > dns_snddq.	740	dlen -= txtlen + 1;
		741	}
		742
		743	// avoid empty TXT rdata
		744	if (offs == rdlen_offs)
		745	(*pkt)[offs++] = 0;
		746
		747	int rdlen = offs - rdlen_offs;
		748
		749	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
		750	(*pkt) [rdlen_offs - 1] = rdlen;
		751
		752	// now update dns_rcv copy
		753	rcv->pkt->len = offs;
		754	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
		755
		756	duplicate_request: ;
482	}	757	}
483		758	else
484	int rdlen = offs - rdlen_offs;	759	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
485
486	(*rep) [rdlen_offs - 2] = rdlen >> 8;
487	(*rep) [rdlen_offs - 1] = rdlen;
488	#endif
489	}	760	}
490	}
491		761
492	pkt->len = offs;	762	pkt->len = offs;
		763	}
		764
493	return pkt;	765	return pkt;
494	}	766	}
495		767
496	void	768	void
497	vpn::dnsv4_client (dns_packet *pkt)	769	vpn::dnsv4_client (dns_packet *pkt)
…		…
500	int offs = 6 * 2; // skip header	772	int offs = 6 * 2; // skip header
501		773
502	pkt->qdcount = ntohs (pkt->qdcount);	774	pkt->qdcount = ntohs (pkt->qdcount);
503	pkt->ancount = ntohs (pkt->ancount);	775	pkt->ancount = ntohs (pkt->ancount);
504		776
		777	// go through our request list and find the corresponding request
505	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	778	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();
506	i != dns_sndpq.end ();	779	i != dns_sndpq.end ();
507	++i)	780	++i)
508	if ((*i)->pkt->id == pkt->id)	781	if ((*i)->pkt->id == pkt->id)
509	{	782	{
510	connection c = (i)->conn;	783	dns_connection dns = (i)->dns;
511	printf ("GOT RESPONSE id %x %p\n", pkt->id, c);//D	784	int seqno = (*i)->seqno;
		785	u8 data[MAXSIZE], *datap = data;
		786
512	delete *i;	787	delete *i;
513	dns_sndpq.erase (i);	788	dns_sndpq.erase (i);
514		789
515	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	790	if (flags & FLAG_RESPONSE && !(flags & (FLAG_OP_MASK \| FLAG_TC)))
516	{	791	{
517	char qname[MAXSIZE];	792	char qname[MAXSIZE];
518		793
519	while (pkt->qdcount-- && offs < MAXSIZE - 4)	794	while (pkt->qdcount-- && offs < MAXSIZE - 4)
520	{	795	{
521	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	796	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
522	offs += 4; // skip qtype, qclass	797	offs += 4; // skip qtype, qclass
523	}	798	}
524		799
525	while (pkt->ancount-- && offs < MAXSIZE - 10)	800	while (pkt->ancount-- && offs < MAXSIZE - 10 && datap)
526	{	801	{
527	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	802	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);
528		803
529	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	804	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];
530	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	805	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];
531	u32 ttl = (*pkt) [offs++] << 24;	806	u32 ttl = (*pkt) [offs++] << 24;
532	ttl \|= (*pkt) [offs++] << 16;	807	ttl \|= (*pkt) [offs++] << 16;
533	ttl \|= (*pkt) [offs++] << 8;	808	ttl \|= (*pkt) [offs++] << 8;
534	ttl \|= (*pkt) [offs++];	809	ttl \|= (*pkt) [offs++];
535		810
536	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	811	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];
537		812
538	printf ("REPLY %d:%d TTL %d RD %d\n", qtype, qclass, ttl, rdlen);
539
540	offs += rdlen;
541
542	if (MAXSIZE - offs < rdlen)	813	if (rdlen <= MAXSIZE - offs)
543	{	814	{
544	// decode bytes, finally	815	// decode bytes, finally
		816
		817	while (rdlen)
		818	{
		819	int txtlen = (*pkt) [offs++];
		820
		821	assert (txtlen + offs < MAXSIZE - 1);
		822
		823	memcpy (datap, pkt->at (offs), txtlen);
		824	datap += txtlen; offs += txtlen;
		825
		826	rdlen -= txtlen + 1;
		827	}
		828	}
		829
		830	int client, rseqno;
		831	decode_header (qname, client, rseqno);
		832
		833	if (client != THISNODE->id)
		834	{
		835	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));
		836	datap = 0;
		837	}
		838	else if (rseqno != seqno)
		839	{
		840	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));
		841	datap = 0;
545	}	842	}
546	}	843	}
547	}	844	}
548		845
		846	// todo: pkt now used
		847	if (datap)
		848	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
		849
549	break;	850	break;
550	}	851	}
		852
		853	delete pkt;
551	}	854	}
552		855
553	void	856	void
554	vpn::dnsv4_ev (io_watcher &w, short revents)	857	vpn::dnsv4_ev (io_watcher &w, short revents)
555	{	858	{
…		…
560	socklen_t sa_len = sizeof (sa);	863	socklen_t sa_len = sizeof (sa);
561		864
562	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	865	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);
563		866
564	if (pkt->len > 0)	867	if (pkt->len > 0)
		868	{
		869	if (pkt->flags & htons (FLAG_TC))
		870	{
		871	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));
		872	//TODO connection reset
		873	}
		874
565	if (THISNODE->dns_port)	875	if (THISNODE->dns_port)
566	{	876	{
567	pkt = dnsv4_server (pkt);	877	pkt = dnsv4_server (pkt);
568	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);	878	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);
569	}	879	}
570	else	880	else
571	dnsv4_client (pkt);	881	dnsv4_client (pkt);
		882	}
572	}	883	}
573	}	884	}
574		885
575	bool	886	bool
576	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	887	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
577	{	888	{
578	// never initialized	889	if (!dns)
579	if (!dns_snddq && !dns_rcvdq)	890	dns = new dns_connection (this);
580	{
581	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
582	dns_snddq = new byte_stream (MAX_BACKLOG);
583
584	dns_rcvseq = dns_sndseq = 0;
585
586	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
587	}
588		891
589	if (!dns_snddq->put (pkt))	892	if (!dns->snddq.put (pkt))
590	return false;	893	return false;
591		894
592	// start timer if neccessary	895	// start timer if neccessary
593	if (!dnsv4_tw.active)	896	if (!THISNODE->dns_port && !dns->tw.active)
594	dnsv4_cb (dnsv4_tw);	897	dns->tw.trigger ();
595		898
596	return true;	899	return true;
597	}	900	}
598		901
599	void	902	void
600	connection::dnsv4_cb (time_watcher &w)	903	dns_connection::time_cb (time_watcher &w)
601	{	904	{
602	// check for timeouts and (re)transmit	905	// check for timeouts and (re)transmit
603	tstamp next = NOW + 60;	906	tstamp next = NOW + 60;
604	dns_req *send = 0;	907	dns_req *send = 0;
605		908
606	slog (L_NOISE, _("dnsv4, %d packets in send queue\n"), vpn->dns_sndpq.size ());
607
608	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	909	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();
609	i != vpn->dns_sndpq.end ();	910	i != vpn->dns_sndpq.end ();
610	++i)	911	++i)
611	{	912	{
612	dns_req r = i;	913	dns_req r = i;
…		…
615	{	916	{
616	if (!send)	917	if (!send)
617	{	918	{
618	send = r;	919	send = r;
619		920
620	slog (L_NOISE, _("dnsv4, send req %d\n"), r->pkt->id);	921	if (r->retry)//D
		922	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
621	r->retry++;	923	r->retry++;
622	r->next = NOW + r->retry;	924	r->next = NOW + r->retry;
623	}	925	}
624	}	926	}
625		927
…		…
627	next = r->next;	929	next = r->next;
628	}	930	}
629		931
630	if (!send	932	if (!send
631	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)	933	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)
632	send = new dns_req (this, dns_sndseq++, dns_snddq);	934	{
		935	send = new dns_req (this);
		936	send->gen_stream_req (sndseq, snddq);
		937	vpn->dns_sndpq.push_back (send);
		938
		939	sndseq = (sndseq + 1) & SEQNO_MASK;
		940	}
633		941
634	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);	942	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
635		943
636	if (send)	944	if (send)
637	{	945	{
638	dns_packet *pkt = send->pkt;	946	dns_packet *pkt = send->pkt;
639		947
640	next = min_next;	948	next = min_next;
641		949
642	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0, dns_si.sav4 (), dns_si.salenv4 ());	950	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0,
		951	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
643	}	952	}
644	else if (next < min_next)	953	else if (next < min_next)
645	next = min_next;	954	next = min_next;
646		955
647	w.start (next);	956	w.start (next);

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.4 by pcg, Wed Mar 2 05:49:31 2005 UTC vs. Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.4 by pcg, Wed Mar 2 05:49:31 2005 UTC vs.
Revision 1.9 by pcg, Fri Mar 4 04:52:38 2005 UTC