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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.5 by pcg, Thu Mar 3 07:24:57 2005 UTC vs.
Revision 1.10 by pcg, Fri Mar 4 08:15:04 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_POLL_INTERVAL .2 // how often to poll minimally when the server is having data
45	#define MAX_RETRY 60.	49	#define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data
		50	#define ACTIVITY_INTERVAL 5.
46		51
		52	#define INITIAL_TIMEOUT 1.
		53	#define INITIAL_SYN_TIMEOUT 2.
		54
		55	#define MIN_SEND_INTERVAL (1./1000.)
		56	#define MAX_SEND_INTERVAL 0.5 // optimistic?
		57
47	#define MAX_OUTSTANDING 40 // max. outstanding requests	58	#define MAX_OUTSTANDING 400 // max. outstanding requests
48	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING	59	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING
49	#define MAX_RATE 1000 // requests/s	60	#define MAX_RATE 100 // requests/s
50	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	61	#define MAX_BACKLOG (100*1024) // size of protocol backlog, must be > MAXSIZE
51		62
52	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	63	#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	64	// 240 leaves about 4 bytes of server reply data
54	// every two request byte sless give room for one reply byte	65	// every two request byte sless give room for one reply byte
55		66
56	#define SEQNO_MASK 0xffff	67	#define SEQNO_MASK 0xffff
57		68	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
58	/*
59
60	protocol, in shorthand :)
61
62	client -> server <req> ANY?
63	server -> client <req> TXT <rep>
64
65	<req> is dns64-encoded <client-id:12><recv-seqno:10>[<send-seqno:10><data>]
66	<rep> is dns64-encoded <0:12><recv-seqno:10>[<send-seqno:10><data>]
67
68	if <client-id> is zero, the connection will be configured:
69
70	<0:12><0:4>client-id:12><default-ttl:8><max-size:16><flags:16>
71
72	*/
73		69
74	#define MAX_LBL_SIZE 63	70	#define MAX_LBL_SIZE 63
75	#define MAX_PKT_SIZE 512	71	#define MAX_PKT_SIZE 512
76		72
		73	#define RR_TYPE_A 1
		74	#define RR_TYPE_NULL 10
77	#define RR_TYPE_TXT 16	75	#define RR_TYPE_TXT 16
78	#define RR_TYPE_ANY 255	76	#define RR_TYPE_ANY 255
		77
79	#define RR_CLASS_IN 1	78	#define RR_CLASS_IN 1
80		79
81	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)	80	#define CMD_IP_1 207
82	struct dns64	81	#define CMD_IP_2 46
83	{	82	#define CMD_IP_3 236
84	static const char encode_chars[64 + 1];	83	#define CMD_IP_RST 29
85	static s8 decode_chars[256];	84	#define CMD_IP_SYN 113
		85	#define CMD_IP_REJ 32
86		86
87	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }	87	// works for cmaps up to 255 (not 256!)
88	static int decode_len (int bytes) { return (bytes * 6) / 8; }	88	struct charmap
		89	{
		90	enum { INVALID = (u8)255 };
		91
		92	char encode [256]; // index => char
		93	u8 decode [256]; // char => index
		94	unsigned int size;
		95
		96	charmap (const char *cmap);
		97	};
		98
		99	charmap::charmap (const char *cmap)
		100	{
		101	char *enc = encode;
		102	u8 *dec = decode;
		103
		104	memset (enc, (char) 0, 256);
		105	memset (dec, (char)INVALID, 256);
		106
		107	for (size = 0; cmap [size]; size++)
		108	{
		109	enc [size] = cmap [size];
		110	dec [(u8)enc [size]] = size;
		111	}
		112
		113	assert (size < 256);
		114	}
		115
		116	#define MAX_DEC_LEN 500
		117	#define MAX_ENC_LEN (MAX_DEC_LEN * 2)
		118	#define MAX_LIMBS ((MAX_DEC_LEN * 8 + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS)
		119
		120	// ugly. minimum base is 16(!)
		121	struct basecoder
		122	{
		123	charmap cmap;
		124	unsigned int enc_len [MAX_DEC_LEN];
		125	unsigned int dec_len [MAX_ENC_LEN];
		126
		127	unsigned int encode_len (unsigned int len);
		128	unsigned int decode_len (unsigned int len);
		129
89	static int encode (char dst, u8 src, int len);	130	unsigned int encode (char dst, u8 src, unsigned int len);
90	static int decode (u8 dst, char src, int len);	131	unsigned int decode (u8 dst, char src, unsigned int len);
91		132
92	dns64 ();	133	basecoder (const char *cmap);
93	} dns64;	134	};
94		135
95	const char dns64::encode_chars[64 + 1] = "_4B9dLphHzrqQmGjkTbJt5svlZX8xSaReEYfwKgF1DP2W6NyVOU70IouACcMn3i-";	136	basecoder::basecoder (const char *cmap)
96	s8 dns64::decode_chars[256];	137	: cmap (cmap)
97
98	dns64::dns64 ()
99	{	138	{
100	for (int i = 0; i < 64; i++)	139	for (unsigned int len = 0; len < MAX_DEC_LEN; ++len)
101	decode_chars [encode_chars [i]] = i + 1;	140	{
102	}	141	u8 src [MAX_DEC_LEN];
		142	u8 dst [MAX_ENC_LEN];
103		143
104	int dns64::encode (char dst, u8 src, int len)	144	memset (src, 255, len);
		145
		146	mp_limb_t m [MAX_LIMBS];
		147	mp_size_t n;
		148
		149	n = mpn_set_str (m, src, len, 256);
		150	n = mpn_get_str (dst, this->cmap.size, m, n);
		151
		152	for (int i = 0; !dst [i]; ++i)
		153	n--;
		154
		155	enc_len [len] = n;
		156	dec_len [n] = len;
		157	}
		158	}
		159
		160	unsigned int basecoder::encode_len (unsigned int len)
105	{	161	{
106	// slow, but easy to debug	162	return enc_len [len];
107	char *beg = dst;	163	}
108	unsigned int accum, bits = 0;	164
		165	unsigned int basecoder::decode_len (unsigned int len)
		166	{
		167	while (len && !dec_len [len])
		168	--len;
		169
		170	return dec_len [len];
		171	}
		172
		173	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
		174	{
		175	if (!len \|\| len > MAX_DEC_LEN)
		176	return 0;
		177
		178	int elen = encode_len (len);
		179
		180	mp_limb_t m [MAX_LIMBS];
		181	mp_size_t n;
		182
		183	u8 dst_ [MAX_ENC_LEN];
		184
		185	n = mpn_set_str (m, src, len, 256);
		186	n = mpn_get_str (dst_, cmap.size, m, n);
		187
		188	int plen = elen; // for padding
		189
		190	while (n < plen)
		191	{
		192	*dst++ = cmap.encode [0];
		193	plen--;
		194	}
		195
		196	for (unsigned int i = n - plen; i < n; ++i)
		197	*dst++ = cmap.encode [dst_ [i]];
		198
		199	return elen;
		200	}
		201
		202	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
		203	{
		204	if (!len \|\| len > MAX_ENC_LEN)
		205	return 0;
		206
		207	u8 src_ [MAX_ENC_LEN];
		208	unsigned int elen = 0;
109		209
110	while (len--)	210	while (len--)
111	{	211	{
112	accum <<= 8;	212	u8 val = cmap.decode [(u8)*src++];
113	accum \|= *src++;
114	bits += 8;
115		213
116	while (bits >= 6)	214	if (val != charmap::INVALID)
117	{	215	src_ [elen++] = val;
118	*dst++ = encode_chars [(accum >> (bits - 6)) & 63];	216	}
119	bits -= 6;	217
120	}	218	int dlen = decode_len (elen);
		219
		220	mp_limb_t m [MAX_LIMBS];
		221	mp_size_t n;
		222
		223	u8 dst_ [MAX_DEC_LEN];
		224
		225	n = mpn_set_str (m, src_, elen, cmap.size);
		226	n = mpn_get_str (dst_, 256, m, n);
		227
		228	if (n < dlen)
121	}	229	{
		230	memset (dst, 0, dlen - n);
		231	memcpy (dst + dlen - n, dst_, n);
		232	}
		233	else
		234	memcpy (dst, dst_ + n - dlen, dlen);
122		235
123	if (bits)	236	return dlen;
124	*dst++ = encode_chars [(accum << (6 - bits)) & 63];
125
126	return dst - beg;
127	}	237	}
128		238
129	int dns64::decode (u8 dst, char src, int len)	239	#if 0
130	{	240	struct test { test (); } test;
131	// slow, but easy to debug
132	u8 *beg = dst;
133	unsigned int accum, bits = 0;
134		241
135	while (len--)	242	test::test ()
		243	{
		244	basecoder cdc ("0123456789abcdefghijklmnopqrstuvwxyz");
		245
		246	u8 in[] = "0123456789abcdefghijklmnopqrstuvwxyz";
		247	static char enc[200];
		248	static u8 dec[200];
		249
		250	for (int i = 1; i < 20; i++)
136	{	251	{
137	s8 chr = decode_chars [(u8)*src++];	252	int elen = cdc.encode (enc, in, i);
		253	int dlen = cdc.decode (dec, enc, elen);
138		254
139	if (!chr)	255	printf ("%d>%d>%d (%s>%s)\n", i, elen, dlen, enc, dec);
140	continue;
141
142	accum <<= 6;
143	accum \|= chr - 1;
144	bits += 6;
145
146	while (bits >= 8)
147	{
148	*dst++ = accum >> (bits - 8);
149	bits -= 8;
150	}
151	}	256	}
		257	abort ();
		258	}
		259	#endif
152		260
153	return dst - beg;	261	//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
		262	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
		263	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
		264	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
		265	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
		266
		267	/////////////////////////////////////////////////////////////////////////////
		268
		269	#define HDRSIZE 6
		270
		271	inline void encode_header (char *data, int clientid, int seqno)
		272	{
		273	u8 hdr[3] = { clientid, seqno >> 8, seqno };
		274
		275	assert (clientid < 256);
		276
		277	cdc26.encode (data, hdr, 3);
		278	}
		279
		280	inline void decode_header (char *data, int &clientid, int &seqno)
		281	{
		282	u8 hdr[3];
		283
		284	cdc26.decode (hdr, data, HDRSIZE);
		285
		286	clientid = hdr[0];
		287	seqno = (hdr[1] << 8) \| hdr[2];
154	}	288	}
155		289
156	/////////////////////////////////////////////////////////////////////////////	290	/////////////////////////////////////////////////////////////////////////////
157		291
158	struct byte_stream	292	struct byte_stream
…		…
210	return false;	344	return false;
211		345
212	data [fill++] = pkt->len >> 8;	346	data [fill++] = pkt->len >> 8;
213	data [fill++] = pkt->len;	347	data [fill++] = pkt->len;
214		348
215	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	349	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
216		350
217	return true;	351	return true;
218	}	352	}
219		353
220	vpn_packet *byte_stream::get ()	354	vpn_packet *byte_stream::get ()
221	{	355	{
222	int len = (data [0] << 8) \| data [1];	356	int len = (data [0] << 8) \| data [1];
223
224	printf ("get len %d, fill %d\n", len, fill);//D
225		357
226	if (len > MAXSIZE && fill >= 2)	358	if (len > MAXSIZE && fill >= 2)
227	abort (); // TODO handle this gracefully, connection reset	359	abort (); // TODO handle this gracefully, connection reset
228		360
229	if (fill < len + 2)	361	if (fill < len + 2)
230	return 0;	362	return 0;
231		363
232	vpn_packet *pkt = new vpn_packet;	364	vpn_packet *pkt = new vpn_packet;
233		365
234	pkt->len = len;	366	pkt->len = len;
235	memcpy (&((*pkt)[0]), data + 2, len);	367	memcpy (pkt->at (0), data + 2, len);
236	remove (len + 2);	368	remove (len + 2);
237		369
238	return pkt;	370	return pkt;
239	}	371	}
240		372
241	/////////////////////////////////////////////////////////////////////////////	373	/////////////////////////////////////////////////////////////////////////////
242		374
243	#define FLAG_QUERY ( 0 << 15)	375	#define FLAG_QUERY ( 0 << 15)
244	#define FLAG_RESPONSE ( 1 << 15)	376	#define FLAG_RESPONSE ( 1 << 15)
245	#define FLAG_OP_MASK (15 << 14)	377	#define FLAG_OP_MASK (15 << 11)
246	#define FLAG_OP_QUERY ( 0 << 11)	378	#define FLAG_OP_QUERY ( 0 << 11)
247	#define FLAG_AA ( 1 << 10)	379	#define FLAG_AA ( 1 << 10)
248	#define FLAG_TC ( 1 << 9)	380	#define FLAG_TC ( 1 << 9)
249	#define FLAG_RD ( 1 << 8)	381	#define FLAG_RD ( 1 << 8)
250	#define FLAG_RA ( 1 << 7)	382	#define FLAG_RA ( 1 << 7)
…		…
257	#define FLAG_RCODE_REFUSED ( 5 << 0)	389	#define FLAG_RCODE_REFUSED ( 5 << 0)
258		390
259	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	391	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
260	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)	392	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
261		393
		394	struct dns_cfg
		395	{
		396	static int next_uid;
		397
		398	u8 id1, id2, id3, id4;
		399	u8 version;
		400	u8 rrtype;
		401	u8 flags;
		402	u8 def_ttl;
		403	u8 rcv_cdc;
		404	u8 snd_cdc;
		405	u16 max_size;
		406	u16 client;
		407	u16 uid; // to make request unique
		408
		409	u8 reserved[8];
		410
		411	void reset (int clientid);
		412	bool valid ();
		413	};
		414
		415	int dns_cfg::next_uid;
		416
		417	void dns_cfg::reset (int clientid)
		418	{
		419	id1 = 'G';
		420	id2 = 'V';
		421	id3 = 'P';
		422	id4 = 'E';
		423
		424	version = 1;
		425
		426	rrtype = RR_TYPE_TXT;
		427	flags = 0;
		428	def_ttl = 0;
		429	rcv_cdc = 0;
		430	snd_cdc = 62;
		431	max_size = ntohs (MAX_PKT_SIZE);
		432	client = ntohs (clientid);
		433	uid = next_uid++;
		434
		435	memset (reserved, 0, 8);
		436	}
		437
		438	bool dns_cfg::valid ()
		439	{
		440	return id1 == 'G'
		441	&& id2 == 'V'
		442	&& id3 == 'P'
		443	&& id4 == 'E'
		444	&& version == 1
		445	&& flags == 0
		446	&& rcv_cdc == 0
		447	&& snd_cdc == 62
		448	&& max_size == ntohs (MAX_PKT_SIZE);
		449	}
		450
262	struct dns_packet : net_packet	451	struct dns_packet : net_packet
263	{	452	{
264	u16 id;	453	u16 id;
265	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	454	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
266	u16 qdcount, ancount, nscount, arcount;	455	u16 qdcount, ancount, nscount, arcount;
…		…
304	return data - orig;	493	return data - orig;
305	}	494	}
306		495
307	/////////////////////////////////////////////////////////////////////////////	496	/////////////////////////////////////////////////////////////////////////////
308		497
309	struct dns_req	498	struct dns_snd
310	{	499	{
311	dns_packet *pkt;	500	dns_packet *pkt;
312	tstamp next;	501	tstamp timeout, sent;
313	int retry;	502	int retry;
314	connection *conn;	503	struct dns_connection *dns;
315	int seqno;	504	int seqno;
316		505
317	dns_req (connection *c);	506	dns_snd (dns_connection *dns);
318	void gen_stream_req (int seqno, byte_stream *stream);	507	void gen_stream_req (int seqno, byte_stream &stream);
		508	void gen_syn_req (const dns_cfg &cfg);
319	};	509	};
320		510
321	static u16 dns_id = 12098; // TODO: should be per-vpn	511	static u16 dns_id = 12098; // TODO: should be per-vpn
322		512
323	static u16 next_id ()	513	static u16 next_id ()
…		…
330	^ (dns_id >> 15)) & 1);	520	^ (dns_id >> 15)) & 1);
331		521
332	return dns_id;	522	return dns_id;
333	}	523	}
334		524
335	dns_req::dns_req (connection *c)	525	dns_snd::dns_snd (dns_connection *dns)
336	: conn (c)	526	: dns (dns)
337	{	527	{
338	next = 0;	528	timeout = 0;
339	retry = 0;	529	retry = 0;
		530	seqno = 0;
340		531
341	pkt = new dns_packet;	532	pkt = new dns_packet;
342		533
343	pkt->id = next_id ();	534	pkt->id = next_id ();
344	}	535	}
345		536
		537	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		538	{
		539	// add tunnel domain
		540	for (;;)
		541	{
		542	const char *end = strchr (domain, '.');
		543
		544	if (!end)
		545	end = domain + strlen (domain);
		546
		547	int len = end - domain;
		548
		549	pkt [offs++] = len;
		550	memcpy (pkt.at (offs), domain, len);
		551	offs += len;
		552
		553	if (!*end)
		554	break;
		555
		556	domain = end + 1;
		557	}
		558	}
		559
346	void dns_req::gen_stream_req (int seqno, byte_stream *stream)	560	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
347	{	561	{
348	this->seqno = seqno;	562	this->seqno = seqno;
		563
		564	timeout = NOW + INITIAL_TIMEOUT;
349		565
350	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	566	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
351	pkt->qdcount = htons (1);	567	pkt->qdcount = htons (1);
352		568
353	int offs = 6*2;	569	int offs = 6*2;
354	int dlen = MAX_DOMAIN_SIZE - strlen (THISNODE->domain) - 2;	570	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);
355	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	571	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
356	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra	572	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
357		573
358	u8 data[256]; //TODO
359
360	data[0] = THISNODE->id; //TODO
361	data[1] = seqno >> 8; //TODO
362	data[2] = seqno; //TODO
363
364	int datalen = dns64::decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE) - 3;
365
366	if (datalen > stream->size ())
367	datalen = stream->size ();
368
369	char enc[256], *encp = enc;	574	char enc[256], *encp = enc;
370		575	encode_header (enc, THISNODE->id, seqno);
371	memcpy (data + 3, stream->begin (), datalen);	576
372	int enclen = dns64::encode (enc, data, datalen + 3);	577	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
		578
		579	if (datalen > stream.size ())
		580	datalen = stream.size ();
		581
		582	int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
373	stream->remove (datalen);	583	stream.remove (datalen);
374		584
375	while (enclen)	585	while (enclen)
376	{	586	{
377	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;	587	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
378		588
…		…
383	encp += lbllen;	593	encp += lbllen;
384		594
385	enclen -= lbllen;	595	enclen -= lbllen;
386	}	596	}
387		597
388	const char *suffix = THISNODE->domain;	598	append_domain (*pkt, offs, THISNODE->domain);
389
390	// add tunnel domain
391	for (;;)
392	{
393	const char *end = strchr (suffix, '.');
394
395	if (!end)
396	end = suffix + strlen (suffix);
397
398	int len = end - suffix;
399
400	(*pkt)[offs++] = len;
401	memcpy (&((*pkt)[offs]), suffix, len);
402	offs += len;
403
404	if (!*end)
405	break;
406
407	suffix = end + 1;
408	}
409		599
410	(*pkt)[offs++] = 0;	600	(*pkt)[offs++] = 0;
411	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	601	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		602	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		603
		604	pkt->len = offs;
		605	}
		606
		607	void dns_snd::gen_syn_req (const dns_cfg &cfg)
		608	{
		609	timeout = NOW + INITIAL_SYN_TIMEOUT;
		610
		611	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		612	pkt->qdcount = htons (1);
		613
		614	int offs = 6*2;
		615
		616	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));
		617
		618	assert (elen <= MAX_LBL_SIZE);
		619
		620	(*pkt)[offs] = elen;
		621	offs += elen + 1;
		622	append_domain (*pkt, offs, THISNODE->domain);
		623
		624	(*pkt)[offs++] = 0;
		625	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
412	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	626	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
413		627
414	pkt->len = offs;	628	pkt->len = offs;
415	}	629	}
416		630
…		…
419	int seqno;	633	int seqno;
420	dns_packet *pkt; // reply packet	634	dns_packet *pkt; // reply packet
421	u8 data [MAXSIZE]; // actually part of the reply packet...	635	u8 data [MAXSIZE]; // actually part of the reply packet...
422	int datalen;	636	int datalen;
423		637
424	dns_rcv (int seqno, dns_packet req, u8 data, int datalen);	638	dns_rcv (int seqno, u8 *data, int datalen);
425	~dns_rcv ();	639	~dns_rcv ();
426	};	640	};
427		641
428	dns_rcv::dns_rcv (int seqno, dns_packet req, u8 data, int datalen)	642	dns_rcv::dns_rcv (int seqno, u8 *data, int datalen)
429	: seqno (seqno), pkt (new dns_packet), datalen (datalen)	643	: seqno (seqno), pkt (new dns_packet), datalen (datalen)
430	{	644	{
431	memcpy (this->data, data, datalen);	645	memcpy (this->data, data, datalen);
432	pkt->len = req->len;
433	memcpy (pkt->at (0), req->at (0), req->len);
434	}	646	}
435		647
436	dns_rcv::~dns_rcv ()	648	dns_rcv::~dns_rcv ()
437	{	649	{
438	delete pkt;	650	delete pkt;
439	}	651	}
440		652
441	/////////////////////////////////////////////////////////////////////////////	653	/////////////////////////////////////////////////////////////////////////////
442		654
443	struct dns_cfg	655	struct dns_connection
444	{	656	{
445	u8 id1, id2, id3;	657	connection *c;
446	u8 def_ttl;	658	struct vpn *vpn;
447	u8 unused1;	659
448	u16 max_size;	660	dns_cfg cfg;
449	u8 flags1, flags2;	661
		662	bool established;
		663
		664	tstamp last_received;
		665	tstamp last_sent;
		666	double poll_interval, send_interval;
		667
		668	vector<dns_rcv *> rcvpq;
		669
		670	byte_stream rcvdq; int rcvseq;
		671	byte_stream snddq; int sndseq;
		672
		673	void time_cb (time_watcher &w); time_watcher tw;
		674	void receive_rep (dns_rcv *r);
		675
		676	dns_connection (connection *c);
		677	~dns_connection ();
450	};	678	};
451		679
		680	dns_connection::dns_connection (connection *c)
		681	: c (c)
		682	, rcvdq (MAX_BACKLOG * 2)
		683	, snddq (MAX_BACKLOG * 2)
		684	, tw (this, &dns_connection::time_cb)
		685	{
		686	vpn = c->vpn;
		687
		688	established = false;
		689
		690	rcvseq = sndseq = 0;
		691
		692	last_sent = last_received = 0;
		693	poll_interval = MIN_POLL_INTERVAL;
		694	send_interval = 0.2; // starting rate
		695	}
		696
		697	dns_connection::~dns_connection ()
		698	{
		699	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		700	i != rcvpq.end ();
		701	++i)
		702	delete *i;
		703	}
		704
452	void connection::dnsv4_receive_rep (struct dns_rcv *r)	705	void dns_connection::receive_rep (dns_rcv *r)
453	{	706	{
		707	if (r->datalen)
		708	{
		709	last_received = NOW;
		710	tw.trigger ();
		711
		712	poll_interval *= 0.99;
		713	if (poll_interval > MIN_POLL_INTERVAL)
		714	poll_interval = MIN_POLL_INTERVAL;
		715	}
		716	else
		717	{
		718	poll_interval *= 1.1;
		719	if (poll_interval > MAX_POLL_INTERVAL)
		720	poll_interval = MAX_POLL_INTERVAL;
		721	}
		722
454	dns_rcvpq.push_back (r);	723	rcvpq.push_back (r);
455		724
456	redo:	725	redo:
457		726
		727	// find next packet
458	for (vector<dns_rcv *>::iterator i = dns_rcvpq.begin ();	728	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
459	i != dns_rcvpq.end ();
460	++i)
461	if (dns_rcvseq == (*i)->seqno)	729	if (SEQNO_EQ (rcvseq, (*i)->seqno))
462	{	730	{
		731	// enter the packet into our input stream
463	dns_rcv r = i;	732	r = *i;
464		733
465	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;	734	// remove the oldest packet, look forward, as it's oldest first
466		735	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
467	if (!dns_snddq && !dns_rcvdq)	736	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
468	{	737	{
469	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);	738	delete *j;
470	dns_snddq = new byte_stream (MAX_BACKLOG);	739	rcvpq.erase (j);
471		740	break;
472	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
473	}	741	}
474		742
		743	rcvseq = (rcvseq + 1) & SEQNO_MASK;
		744
475	if (!dns_rcvdq->put (r->data, r->datalen))	745	if (!rcvdq.put (r->data, r->datalen))
476	abort (); // MUST never overflow, can be caused by data corruption, TODO	746	abort (); // MUST never overflow, can be caused by data corruption, TODO
477		747
478	while (vpn_packet *pkt = dns_rcvdq->get ())	748	while (vpn_packet *pkt = rcvdq.get ())
479	{	749	{
480	sockinfo si;	750	sockinfo si;
481	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	751	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;
482		752
483	vpn->recv_vpn_packet (pkt, si);	753	vpn->recv_vpn_packet (pkt, si);
484	}	754	}
485	}	755
486	else if ((u32)dns_rcvseq - MAX_WINDOW - (u32)(i)->seqno < MAX_WINDOW 2)	756	// check for further packets
487	{
488	dns_rcvpq.erase (i);
489	goto redo;	757	goto redo;
490	}	758	}
491	}	759	}
492		760
493	dns_packet *	761	void
494	vpn::dnsv4_server (dns_packet *pkt)	762	vpn::dnsv4_server (dns_packet &pkt)
495	{	763	{
496	u16 flags = ntohs (pkt->flags);	764	u16 flags = ntohs (pkt.flags);
497		765
498	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
499	int offs = 6 * 2; // skip header	766	int offs = 6 * 2; // skip header
500		767
501	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	768	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
502		769
503	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	770	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
504	&& pkt->qdcount == htons (1))	771	&& pkt.qdcount == htons (1))
505	{	772	{
506	char qname[MAXSIZE];	773	char qname[MAXSIZE];
507	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	774	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
508		775
509	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	776	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
510	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	777	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
511		778
512	pkt->qdcount = htons (1);	779	pkt.qdcount = htons (1);
513	pkt->ancount = 0;	780	pkt.ancount = 0;
514	pkt->nscount = 0; // should be self, as other nameservers reply like this	781	pkt.nscount = 0; // should be self, as other nameservers reply like this
515	pkt->arcount = 0; // a record for self, as other nameservers reply like this	782	pkt.arcount = 0; // a record for self, as other nameservers reply like this
516		783
517	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	784	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);
518		785
519	int dlen = strlen (THISNODE->domain);	786	int dlen = strlen (THISNODE->domain);
520		787
521	if (qclass == RR_CLASS_IN	788	if (qclass == RR_CLASS_IN
522	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
523	&& qlen > dlen + 1	789	&& qlen > dlen + 1
524	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	790	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
525	{	791	{
526	// correct class, domain: parse	792	// now generate reply
527	u8 data[MAXSIZE];	793	pkt.ancount = htons (1); // one answer RR
528	int datalen = dns64::decode (data, qname, qlen - dlen - 1);	794	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
529		795
530	int client = data[0];	796	if ((qtype == RR_TYPE_ANY
531	int seqno = ((data[1] << 8) \| data[2]) & SEQNO_MASK;	797	\|\| qtype == RR_TYPE_TXT
532		798	\|\| qtype == RR_TYPE_NULL)
533	if (0 < client && client <= conns.size ())	799	&& qlen > dlen + 1 + HDRSIZE)
534	{	800	{
535	connection *c = conns [client - 1];	801	// correct class, domain: parse
		802	int client, seqno;
		803	decode_header (qname, client, seqno);
536		804
537	for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.begin ();	805	u8 data[MAXSIZE];
538	i != c->dns_rcvpq.end ();	806	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
539	++i)
540	if ((*i)->seqno == seqno)
541	{
542	// already seen that request, just reply with the original reply
543	dns_rcv r = i;
544		807
545	offs = r->pkt->len;	808	if (0 < client && client <= conns.size ())
546	memcpy (pkt->at (0), r->pkt->at (0), offs);
547	goto duplicate_request;
548	}
549
550	// new packet, queue
551	c->dnsv4_receive_rep (new dns_rcv (seqno, pkt, data + 3, datalen - 3));
552
553	// now generate reply
554	pkt->ancount = htons (1); // one answer RR
555	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
556
557	(*pkt) [offs++] = 0xc0;
558	(pkt) [offs++] = 6 2; // same as in query section
559
560	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;
561	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;
562
563	(pkt) [offs++] = 0; (pkt) [offs++] = 0;
564	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL
565
566	int dlen = MAX_PKT_SIZE - offs - 2;
567
568	// bind doesn't compress well, so reduce further by one label length
569	dlen -= qlen;
570
571	int rdlen_offs = offs += 2;
572
573	while (c->dns_snddq
574	&& !c->dns_snddq->empty ()
575	&& dlen > 1)
576	{	809	{
		810	connection *c = conns [client - 1];
		811	dns_connection *dns = c->dns;
		812	dns_rcv *rcv;
		813
		814	if (dns)
		815	{
		816	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
		817	if (SEQNO_EQ ((*i)->seqno, seqno))
		818	{
		819	// already seen that request: simply reply with the cached reply
		820	dns_rcv r = i;
		821
		822	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D
		823
		824	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		825	pkt.id = r->pkt->id;
		826	goto duplicate_request;
		827	}
		828
		829	// new packet, queue
		830	rcv = new dns_rcv (seqno, data, datalen);
		831	dns->receive_rep (rcv);
		832	}
		833
		834	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		835
		836	// type
		837	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		838	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype;
		839
		840	// class
		841	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN;
		842
		843	// TTL
		844	pkt [offs++] = 0; pkt [offs++] = 0;
		845	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0;
		846
		847	int rdlen_offs = offs += 2;
		848
		849	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
		850	// bind doesn't compress well, so reduce further by one label length
		851	dlen -= qlen;
		852
		853	if (dns)
		854	{
		855	while (dlen > 1 && !dns->snddq.empty ())
		856	{
577	int txtlen = dlen <= 255 ? dlen - 1 : 255;	857	int txtlen = dlen <= 255 ? dlen - 1 : 255;
578		858
579	if (txtlen > c->dns_snddq->size ())	859	if (txtlen > dns->snddq.size ())
580	txtlen = c->dns_snddq->size ();	860	txtlen = dns->snddq.size ();
581		861
582	(*pkt)[offs++] = txtlen;	862	pkt[offs++] = txtlen;
583	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);	863	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
584	offs += txtlen;	864	offs += txtlen;
585	c->dns_snddq->remove (txtlen);	865	dns->snddq.remove (txtlen);
586		866
587	dlen -= txtlen + 1;	867	dlen -= txtlen + 1;
		868	}
		869
		870	// avoid empty TXT rdata
		871	if (offs == rdlen_offs)
		872	pkt[offs++] = 0;
		873	}
		874	else
		875	{
		876	// send RST
		877	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		878	pkt [offs++] = CMD_IP_RST;
		879	}
		880
		881	int rdlen = offs - rdlen_offs;
		882
		883	pkt [rdlen_offs - 2] = rdlen >> 8;
		884	pkt [rdlen_offs - 1] = rdlen;
		885
		886	if (dns)
		887	{
		888	// now update dns_rcv copy
		889	rcv->pkt->len = offs;
		890	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		891	}
		892
		893	duplicate_request: ;
588	}	894	}
589		895	else
590	// avoid empty TXT rdata	896	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
591	if (offs == rdlen_offs)
592	(*pkt)[offs++] = 0;
593
594	int rdlen = offs - rdlen_offs;
595
596	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
597	(*pkt) [rdlen_offs - 1] = rdlen;
598
599	duplicate_request: ;
600	}	897	}
601	else	898	else if (qtype == RR_TYPE_A
602	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	899	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		900	{
		901	dns_cfg cfg;
		902	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		903	int client = ntohs (cfg.client);
		904
		905	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		906
		907	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
		908	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		909	pkt [offs++] = 0; pkt [offs++] = 0;
		910	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		911	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
		912
		913	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);
		914
		915	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		916	pkt [offs++] = CMD_IP_REJ;
		917
		918	if (0 < client && client <= conns.size ())
		919	{
		920	connection *c = conns [client - 1];
		921
		922	if (cfg.valid ())
		923	{
		924	pkt [offs - 1] = CMD_IP_SYN;
		925
		926	delete c->dns;
		927	c->dns = new dns_connection (c);
		928	c->dns->cfg = cfg;
		929	}
		930	}
		931	}
603	}	932	}
604	}
605	else
606	offs = pkt->len;
607		933
608	pkt->len = offs;	934	pkt.len = offs;
609	return pkt;	935	}
610	}	936	}
611		937
612	void	938	void
613	vpn::dnsv4_client (dns_packet *pkt)	939	vpn::dnsv4_client (dns_packet &pkt)
614	{	940	{
615	u16 flags = ntohs (pkt->flags);	941	u16 flags = ntohs (pkt.flags);
616	int offs = 6 * 2; // skip header	942	int offs = 6 * 2; // skip header
617		943
618	pkt->qdcount = ntohs (pkt->qdcount);	944	pkt.qdcount = ntohs (pkt.qdcount);
619	pkt->ancount = ntohs (pkt->ancount);	945	pkt.ancount = ntohs (pkt.ancount);
620		946
621	// go through our request list and find the corresponding request	947	// go through our request list and find the corresponding request
622	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	948	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
623	i != dns_sndpq.end ();	949	i != dns_sndpq.end ();
624	++i)	950	++i)
625	if ((*i)->pkt->id == pkt->id)	951	if ((*i)->pkt->id == pkt.id)
626	{	952	{
627	connection c = (i)->conn;	953	dns_connection dns = (i)->dns;
628	int seqno = (*i)->seqno;	954	int seqno = (*i)->seqno;
629	u8 data[MAXSIZE], *datap = data;	955	u8 data[MAXSIZE], *datap = data;
630		956
		957	if ((*i)->retry)
		958	{
		959	dns->send_interval *= 1.01;
		960	if (dns->send_interval < MAX_SEND_INTERVAL)
		961	dns->send_interval = MAX_SEND_INTERVAL;
		962	}
		963	else
		964	{
		965	dns->send_interval *= 0.99;
		966	if (dns->send_interval < MIN_SEND_INTERVAL)
		967	dns->send_interval = MIN_SEND_INTERVAL;
		968
		969	// the latency surely puts an upper bound on
		970	// the minimum send interval
		971	if (dns->send_interval > NOW - (*i)->sent)
		972	dns->send_interval = NOW - (*i)->sent;
		973	}
		974
631	delete *i;	975	delete *i;
632	dns_sndpq.erase (i);	976	dns_sndpq.erase (i);
633		977
634	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	978	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
635	{	979	{
636	char qname[MAXSIZE];	980	char qname[MAXSIZE];
637		981
638	while (pkt->qdcount-- && offs < MAXSIZE - 4)	982	while (pkt.qdcount-- && offs < MAXSIZE - 4)
639	{	983	{
640	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	984	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
641	offs += 4; // skip qtype, qclass	985	offs += 4; // skip qtype, qclass
642	}	986	}
643		987
644	while (pkt->ancount-- && offs < MAXSIZE - 10)	988	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
645	{	989	{
646	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	990	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
647		991
648	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	992	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
649	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	993	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
650	u32 ttl = (*pkt) [offs++] << 24;	994	u32 ttl = pkt [offs++] << 24;
651	ttl \|= (*pkt) [offs++] << 16;	995	ttl \|= pkt [offs++] << 16;
652	ttl \|= (*pkt) [offs++] << 8;	996	ttl \|= pkt [offs++] << 8;
653	ttl \|= (*pkt) [offs++];	997	ttl \|= pkt [offs++];
654
655	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	998	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
656		999
657	if (rdlen <= MAXSIZE - offs)	1000	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
658	{	1001	{
659	// decode bytes, finally	1002	if (rdlen <= MAXSIZE - offs)
660
661	while (rdlen)
662	{	1003	{
		1004	// decode bytes, finally
		1005
		1006	while (rdlen)
		1007	{
663	int txtlen = (*pkt) [offs++];	1008	int txtlen = pkt [offs++];
664		1009
665	assert (txtlen + offs < MAXSIZE - 1);	1010	assert (txtlen + offs < MAXSIZE - 1);
666		1011
667	memcpy (datap, pkt->at (offs), txtlen);	1012	memcpy (datap, pkt.at (offs), txtlen);
668	datap += txtlen; offs += txtlen;	1013	datap += txtlen; offs += txtlen;
669		1014
670	rdlen -= txtlen + 1;	1015	rdlen -= txtlen + 1;
		1016	}
671	}	1017	}
672
673	}	1018	}
		1019	else if (qtype == RR_TYPE_A)
		1020	{
		1021	u8 ip [4];
674		1022
		1023	ip [0] = pkt [offs++];
		1024	ip [1] = pkt [offs++];
		1025	ip [2] = pkt [offs++];
		1026	ip [3] = pkt [offs++];
		1027
		1028	if (ip [0] == CMD_IP_1
		1029	&& ip [1] == CMD_IP_2
		1030	&& ip [2] == CMD_IP_3)
		1031	{
		1032	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);
		1033
		1034	if (ip [3] == CMD_IP_RST)
		1035	{
		1036	slog (L_DEBUG, _("got tunnel RST request"));
		1037
		1038	connection *c = dns->c;
		1039	delete c->dns; c->dns = 0;
		1040
		1041	return;
		1042	}
		1043	else if (ip [3] == CMD_IP_SYN)
		1044	dns->established = true;
		1045	else
		1046	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);
		1047	}
		1048	else
		1049	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),
		1050	ip [0], ip [1], ip [2], ip [3]);
		1051
		1052	return;
		1053	}
		1054
		1055	int client, rseqno;
		1056	decode_header (qname, client, rseqno);
		1057
		1058	if (client != THISNODE->id)
		1059	{
		1060	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));
		1061	datap = 0;
		1062	}
		1063	else if (rseqno != seqno)
		1064	{
		1065	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));
		1066	datap = 0;
		1067	}
675	}	1068	}
676	}	1069	}
677		1070
		1071	// todo: pkt now used
678	if (datap != data)	1072	if (datap)
679	printf ("%02x %02x %02x %02x\n",
680	data[0],
681	data[1],
682	data[2],
683	data[3]);
684
685	printf ("recv %d,%d\n", pkt->id, seqno, datap - data);//D
686	c->dnsv4_receive_rep (new dns_rcv (seqno, pkt, data, datap - data));	1073	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
687		1074
688	break;	1075	break;
689	}	1076	}
690
691	delete pkt;
692	}	1077	}
693		1078
694	void	1079	void
695	vpn::dnsv4_ev (io_watcher &w, short revents)	1080	vpn::dnsv4_ev (io_watcher &w, short revents)
696	{	1081	{
…		…
698	{	1083	{
699	dns_packet *pkt = new dns_packet;	1084	dns_packet *pkt = new dns_packet;
700	struct sockaddr_in sa;	1085	struct sockaddr_in sa;
701	socklen_t sa_len = sizeof (sa);	1086	socklen_t sa_len = sizeof (sa);
702		1087
703	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1088	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
704		1089
705	if (pkt->len > 0)	1090	if (pkt->len > 0)
706	{	1091	{
707	if (pkt->flags & htons (FLAG_TC))
708	{
709	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));
710	//TODO connection reset
711	}
712
713	if (THISNODE->dns_port)	1092	if (THISNODE->dns_port)
714	{	1093	{
715	pkt = dnsv4_server (pkt);	1094	dnsv4_server (*pkt);
716	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);	1095	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
717	}	1096	}
718	else	1097	else
719	dnsv4_client (pkt);	1098	dnsv4_client (*pkt);
		1099
		1100	delete pkt;
720	}	1101	}
721	}	1102	}
722	}	1103	}
723		1104
724	bool	1105	bool
725	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1106	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
726	{	1107	{
727	// never initialized	1108	if (!dns)
728	if (!dns_snddq && !dns_rcvdq)	1109	dns = new dns_connection (this);
729	{
730	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
731	dns_snddq = new byte_stream (MAX_BACKLOG);
732
733	//dns_rcvseq = dns_sndseq = 0;
734
735	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
736	}
737		1110
738	if (!dns_snddq->put (pkt))	1111	if (!dns->snddq.put (pkt))
739	return false;	1112	return false;
740		1113
741	// start timer if neccessary	1114	dns->tw.trigger ();
742	if (!THISNODE->dns_port && !dnsv4_tw.active)
743	dnsv4_cb (dnsv4_tw);
744		1115
745	return true;	1116	return true;
746	}	1117	}
747		1118
		1119	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1120
748	void	1121	void
749	connection::dnsv4_cb (time_watcher &w)	1122	dns_connection::time_cb (time_watcher &w)
750	{	1123	{
		1124	// servers have to be polled
		1125	if (THISNODE->dns_port)
		1126	return;
		1127
751	// check for timeouts and (re)transmit	1128	// check for timeouts and (re)transmit
752	tstamp next = NOW + 60;	1129	tstamp next = NOW + poll_interval;
753	dns_req *send = 0;	1130	dns_snd *send = 0;
754		1131
755	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1132	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
756	i != vpn->dns_sndpq.end ();	1133	i != vpn->dns_sndpq.end ();
757	++i)	1134	++i)
758	{	1135	{
759	dns_req r = i;	1136	dns_snd r = i;
760		1137
761	if (r->next <= NOW)	1138	if (r->timeout <= NOW)
762	{	1139	{
763	if (!send)	1140	if (!send)
764	{	1141	{
765	send = r;	1142	send = r;
766		1143
767	if (r->retry)//D
768	printf ("req %d, retry %d\n", r->pkt->id, r->retry);
769	r->retry++;	1144	r->retry++;
770	r->next = NOW + r->retry;	1145	r->timeout = NOW + r->retry;
771	}	1146	}
772	}	1147	}
773
774	if (r->next < next)	1148	else if (r->timeout < next)
775	next = r->next;	1149	NEXT (r->timeout);
		1150	}
		1151
		1152	if (last_sent + send_interval <= NOW)
776	}	1153	{
777
778	if (!send	1154	if (!send)
		1155	{
		1156	// generate a new packet, if wise
		1157
		1158	if (!established)
		1159	{
		1160	if (vpn->dns_sndpq.empty ())
		1161	{
		1162	send = new dns_snd (this);
		1163
		1164	cfg.reset (THISNODE->id);
		1165	send->gen_syn_req (cfg);
		1166	}
		1167	}
779	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)	1168	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
780	{	1169	{
781	send = new dns_req (this);	1170	send = new dns_snd (this);
782	send->gen_stream_req (dns_sndseq, dns_snddq);	1171	send->gen_stream_req (sndseq, snddq);
		1172
		1173	sndseq = (sndseq + 1) & SEQNO_MASK;
		1174	}
		1175
		1176	if (send)
783	vpn->dns_sndpq.push_back (send);	1177	vpn->dns_sndpq.push_back (send);
		1178	}
784		1179
785	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
786	}
787
788	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
789
790	if (send)	1180	if (send)
		1181	{
		1182	printf ("send pkt\n");
		1183	last_sent = NOW;
		1184
		1185	if (!send->retry)
		1186	send->sent = NOW;
		1187
		1188	sendto (vpn->dnsv4_fd,
		1189	send->pkt->at (0), send->pkt->len, 0,
		1190	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
		1191	}
791	{	1192	}
792	dns_packet *pkt = send->pkt;	1193	else
		1194	NEXT (last_sent + send_interval);
793		1195
794	next = min_next;	1196	printf ("pi %f si %f N %f (%d:%d)\n", poll_interval, send_interval, next - NOW, vpn->dns_sndpq.size (), snddq.size ());
795
796	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0, dns_si.sav4 (), dns_si.salenv4 ());
797	}
798	else if (next < min_next)
799	next = min_next;
800		1197
801	w.start (next);	1198	w.start (next);
802	}	1199	}
803		1200
804	#endif	1201	#endif

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.5 by pcg, Thu Mar 3 07:24:57 2005 UTC vs. Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.5 by pcg, Thu Mar 3 07:24:57 2005 UTC vs.
Revision 1.10 by pcg, Fri Mar 4 08:15:04 2005 UTC