[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 1.15 by pcg, Fri Mar 4 10:15:45 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 .02 // how often to poll minimally when the server has 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.
		51
		52	#define INITIAL_TIMEOUT 1. // retry timeouts
		53	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
		54
		55	#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests
		56	#define MAX_SEND_INTERVAL 0.5 // optimistic?
46		57
47	#define MAX_OUTSTANDING 40 // max. outstanding requests	58	#define MAX_OUTSTANDING 40 // max. outstanding requests
48	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING	59	#define MAX_WINDOW 100 // max. for MAX_OUTSTANDING
49	#define MAX_RATE 1000 // requests/s
50	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	60	#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
51		61
52	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	62	#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	63	// 240 leaves about 4 bytes of server reply data
54	// every two request byte sless give room for one reply byte	64	// every two request bytes less give room for one reply byte
55		65
56	#define SEQNO_MASK 0xffff	66	#define SEQNO_MASK 0xffff
57		67	#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		68
74	#define MAX_LBL_SIZE 63	69	#define MAX_LBL_SIZE 63
75	#define MAX_PKT_SIZE 512	70	#define MAX_PKT_SIZE 512
76		71
		72	#define RR_TYPE_A 1
		73	#define RR_TYPE_NULL 10
77	#define RR_TYPE_TXT 16	74	#define RR_TYPE_TXT 16
78	#define RR_TYPE_ANY 255	75	#define RR_TYPE_ANY 255
		76
79	#define RR_CLASS_IN 1	77	#define RR_CLASS_IN 1
80		78
81	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)	79	#define CMD_IP_1 207
82	struct dns64	80	#define CMD_IP_2 46
83	{	81	#define CMD_IP_3 236
84	static const char encode_chars[64 + 1];	82	#define CMD_IP_RST 29
85	static s8 decode_chars[256];	83	#define CMD_IP_SYN 113
		84	#define CMD_IP_REJ 32
86		85
87	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }	86	// works for cmaps up to 255 (not 256!)
88	static int decode_len (int bytes) { return (bytes * 6) / 8; }	87	struct charmap
		88	{
		89	enum { INVALID = (u8)255 };
		90
		91	char encode [256]; // index => char
		92	u8 decode [256]; // char => index
		93	unsigned int size;
		94
		95	charmap (const char *cmap);
		96	};
		97
		98	charmap::charmap (const char *cmap)
		99	{
		100	char *enc = encode;
		101	u8 *dec = decode;
		102
		103	memset (enc, (char) 0, 256);
		104	memset (dec, (char)INVALID, 256);
		105
		106	for (size = 0; cmap [size]; size++)
		107	{
		108	enc [size] = cmap [size];
		109	dec [(u8)enc [size]] = size;
		110	}
		111
		112	assert (size < 256);
		113	}
		114
		115	#define MAX_DEC_LEN 500
		116	#define MAX_ENC_LEN (MAX_DEC_LEN * 2)
		117	#define MAX_LIMBS ((MAX_DEC_LEN * 8 + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS)
		118
		119	// ugly. minimum base is 16(!)
		120	struct basecoder
		121	{
		122	charmap cmap;
		123	unsigned int enc_len [MAX_DEC_LEN];
		124	unsigned int dec_len [MAX_ENC_LEN];
		125
		126	unsigned int encode_len (unsigned int len);
		127	unsigned int decode_len (unsigned int len);
		128
89	static int encode (char dst, u8 src, int len);	129	unsigned int encode (char dst, u8 src, unsigned int len);
90	static int decode (u8 dst, char src, int len);	130	unsigned int decode (u8 dst, char src, unsigned int len);
91		131
92	dns64 ();	132	basecoder (const char *cmap);
93	} dns64;	133	};
94		134
95	const char dns64::encode_chars[64 + 1] = "_4B9dLphHzrqQmGjkTbJt5svlZX8xSaReEYfwKgF1DP2W6NyVOU70IouACcMn3i-";	135	basecoder::basecoder (const char *cmap)
96	s8 dns64::decode_chars[256];	136	: cmap (cmap)
97
98	dns64::dns64 ()
99	{	137	{
100	for (int i = 0; i < 64; i++)	138	for (unsigned int len = 0; len < MAX_DEC_LEN; ++len)
101	decode_chars [encode_chars [i]] = i + 1;	139	{
102	}	140	u8 src [MAX_DEC_LEN];
		141	u8 dst [MAX_ENC_LEN];
103		142
104	int dns64::encode (char dst, u8 src, int len)	143	memset (src, 255, len);
		144
		145	mp_limb_t m [MAX_LIMBS];
		146	mp_size_t n;
		147
		148	n = mpn_set_str (m, src, len, 256);
		149	n = mpn_get_str (dst, this->cmap.size, m, n);
		150
		151	for (int i = 0; !dst [i]; ++i)
		152	n--;
		153
		154	enc_len [len] = n;
		155	dec_len [n] = len;
		156	}
		157	}
		158
		159	unsigned int basecoder::encode_len (unsigned int len)
105	{	160	{
106	// slow, but easy to debug	161	return enc_len [len];
107	char *beg = dst;	162	}
108	unsigned int accum, bits = 0;	163
		164	unsigned int basecoder::decode_len (unsigned int len)
		165	{
		166	while (len && !dec_len [len])
		167	--len;
		168
		169	return dec_len [len];
		170	}
		171
		172	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
		173	{
		174	if (!len \|\| len > MAX_DEC_LEN)
		175	return 0;
		176
		177	int elen = encode_len (len);
		178
		179	mp_limb_t m [MAX_LIMBS];
		180	mp_size_t n;
		181
		182	u8 dst_ [MAX_ENC_LEN];
		183
		184	n = mpn_set_str (m, src, len, 256);
		185	n = mpn_get_str (dst_, cmap.size, m, n);
		186
		187	int plen = elen; // for padding
		188
		189	while (n < plen)
		190	{
		191	*dst++ = cmap.encode [0];
		192	plen--;
		193	}
		194
		195	for (unsigned int i = n - plen; i < n; ++i)
		196	*dst++ = cmap.encode [dst_ [i]];
		197
		198	return elen;
		199	}
		200
		201	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
		202	{
		203	if (!len \|\| len > MAX_ENC_LEN)
		204	return 0;
		205
		206	u8 src_ [MAX_ENC_LEN];
		207	unsigned int elen = 0;
109		208
110	while (len--)	209	while (len--)
111	{	210	{
112	accum <<= 8;	211	u8 val = cmap.decode [(u8)*src++];
113	accum \|= *src++;
114	bits += 8;
115		212
116	while (bits >= 6)	213	if (val != charmap::INVALID)
117	{	214	src_ [elen++] = val;
118	*dst++ = encode_chars [(accum >> (bits - 6)) & 63];	215	}
119	bits -= 6;	216
120	}	217	int dlen = decode_len (elen);
		218
		219	mp_limb_t m [MAX_LIMBS];
		220	mp_size_t n;
		221
		222	u8 dst_ [MAX_DEC_LEN];
		223
		224	n = mpn_set_str (m, src_, elen, cmap.size);
		225	n = mpn_get_str (dst_, 256, m, n);
		226
		227	if (n < dlen)
121	}	228	{
		229	memset (dst, 0, dlen - n);
		230	memcpy (dst + dlen - n, dst_, n);
		231	}
		232	else
		233	memcpy (dst, dst_ + n - dlen, dlen);
122		234
123	if (bits)	235	return dlen;
124	*dst++ = encode_chars [(accum << (6 - bits)) & 63];
125
126	return dst - beg;
127	}	236	}
128		237
129	int dns64::decode (u8 dst, char src, int len)	238	#if 0
130	{	239	struct test { test (); } test;
131	// slow, but easy to debug
132	u8 *beg = dst;
133	unsigned int accum, bits = 0;
134		240
135	while (len--)	241	test::test ()
		242	{
		243	basecoder cdc ("0123456789abcdefghijklmnopqrstuvwxyz");
		244
		245	u8 in[] = "0123456789abcdefghijklmnopqrstuvwxyz";
		246	static char enc[200];
		247	static u8 dec[200];
		248
		249	for (int i = 1; i < 20; i++)
136	{	250	{
137	s8 chr = decode_chars [(u8)*src++];	251	int elen = cdc.encode (enc, in, i);
		252	int dlen = cdc.decode (dec, enc, elen);
138		253
139	if (!chr)	254	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	}	255	}
		256	abort ();
		257	}
		258	#endif
152		259
153	return dst - beg;	260	//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
		261	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
		262	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
		263	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
		264	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
		265
		266	/////////////////////////////////////////////////////////////////////////////
		267
		268	#define HDRSIZE 6
		269
		270	inline void encode_header (char *data, int clientid, int seqno)
		271	{
		272	u8 hdr[3] = { clientid, seqno >> 8, seqno };
		273
		274	assert (clientid < 256);
		275
		276	cdc26.encode (data, hdr, 3);
		277	}
		278
		279	inline void decode_header (char *data, int &clientid, int &seqno)
		280	{
		281	u8 hdr[3];
		282
		283	cdc26.decode (hdr, data, HDRSIZE);
		284
		285	clientid = hdr[0];
		286	seqno = (hdr[1] << 8) \| hdr[2];
154	}	287	}
155		288
156	/////////////////////////////////////////////////////////////////////////////	289	/////////////////////////////////////////////////////////////////////////////
157		290
158	struct byte_stream	291	struct byte_stream
…		…
210	return false;	343	return false;
211		344
212	data [fill++] = pkt->len >> 8;	345	data [fill++] = pkt->len >> 8;
213	data [fill++] = pkt->len;	346	data [fill++] = pkt->len;
214		347
215	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	348	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
216		349
217	return true;	350	return true;
218	}	351	}
219		352
220	vpn_packet *byte_stream::get ()	353	vpn_packet *byte_stream::get ()
221	{	354	{
222	int len = (data [0] << 8) \| data [1];	355	unsigned int len = (data [0] << 8) \| data [1];
223
224	printf ("get len %d, fill %d\n", len, fill);//D
225		356
226	if (len > MAXSIZE && fill >= 2)	357	if (len > MAXSIZE && fill >= 2)
227	abort (); // TODO handle this gracefully, connection reset	358	abort (); // TODO handle this gracefully, connection reset
228		359
229	if (fill < len + 2)	360	if (fill < len + 2)
230	return 0;	361	return 0;
231		362
232	vpn_packet *pkt = new vpn_packet;	363	vpn_packet *pkt = new vpn_packet;
233		364
234	pkt->len = len;	365	pkt->len = len;
235	memcpy (&((*pkt)[0]), data + 2, len);	366	memcpy (pkt->at (0), data + 2, len);
236	remove (len + 2);	367	remove (len + 2);
237		368
238	return pkt;	369	return pkt;
239	}	370	}
240		371
241	/////////////////////////////////////////////////////////////////////////////	372	/////////////////////////////////////////////////////////////////////////////
242		373
243	#define FLAG_QUERY ( 0 << 15)	374	#define FLAG_QUERY ( 0 << 15)
244	#define FLAG_RESPONSE ( 1 << 15)	375	#define FLAG_RESPONSE ( 1 << 15)
245	#define FLAG_OP_MASK (15 << 14)	376	#define FLAG_OP_MASK (15 << 11)
246	#define FLAG_OP_QUERY ( 0 << 11)	377	#define FLAG_OP_QUERY ( 0 << 11)
247	#define FLAG_AA ( 1 << 10)	378	#define FLAG_AA ( 1 << 10)
248	#define FLAG_TC ( 1 << 9)	379	#define FLAG_TC ( 1 << 9)
249	#define FLAG_RD ( 1 << 8)	380	#define FLAG_RD ( 1 << 8)
250	#define FLAG_RA ( 1 << 7)	381	#define FLAG_RA ( 1 << 7)
…		…
257	#define FLAG_RCODE_REFUSED ( 5 << 0)	388	#define FLAG_RCODE_REFUSED ( 5 << 0)
258		389
259	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	390	#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)	391	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
261		392
		393	struct dns_cfg
		394	{
		395	static int next_uid;
		396
		397	u8 id1, id2, id3, id4;
		398	u8 version;
		399	u8 rrtype;
		400	u8 flags;
		401	u8 def_ttl;
		402	u8 rcv_cdc;
		403	u8 snd_cdc;
		404	u16 max_size;
		405	u16 client;
		406	u16 uid; // to make request unique
		407
		408	u8 reserved[8];
		409
		410	void reset (int clientid);
		411	bool valid ();
		412	};
		413
		414	int dns_cfg::next_uid;
		415
		416	void dns_cfg::reset (int clientid)
		417	{
		418	id1 = 'G';
		419	id2 = 'V';
		420	id3 = 'P';
		421	id4 = 'E';
		422
		423	version = 1;
		424
		425	rrtype = RR_TYPE_TXT;
		426	flags = 0;
		427	def_ttl = 0;
		428	rcv_cdc = 0;
		429	snd_cdc = 62;
		430	max_size = ntohs (MAX_PKT_SIZE);
		431	client = ntohs (clientid);
		432	uid = next_uid++;
		433
		434	memset (reserved, 0, 8);
		435	}
		436
		437	bool dns_cfg::valid ()
		438	{
		439	return id1 == 'G'
		440	&& id2 == 'V'
		441	&& id3 == 'P'
		442	&& id4 == 'E'
		443	&& version == 1
		444	&& flags == 0
		445	&& rcv_cdc == 0
		446	&& snd_cdc == 62
		447	&& max_size == ntohs (MAX_PKT_SIZE);
		448	}
		449
262	struct dns_packet : net_packet	450	struct dns_packet : net_packet
263	{	451	{
264	u16 id;	452	u16 id;
265	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	453	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
266	u16 qdcount, ancount, nscount, arcount;	454	u16 qdcount, ancount, nscount, arcount;
…		…
304	return data - orig;	492	return data - orig;
305	}	493	}
306		494
307	/////////////////////////////////////////////////////////////////////////////	495	/////////////////////////////////////////////////////////////////////////////
308		496
309	struct dns_req	497	struct dns_snd
310	{	498	{
311	dns_packet *pkt;	499	dns_packet *pkt;
312	tstamp next;	500	tstamp timeout, sent;
313	int retry;	501	int retry;
314	connection *conn;	502	struct dns_connection *dns;
315	int seqno;	503	int seqno;
316		504
317	dns_req (connection *c);
318	void gen_stream_req (int seqno, byte_stream *stream);	505	void gen_stream_req (int seqno, byte_stream &stream);
		506	void gen_syn_req (const dns_cfg &cfg);
		507
		508	dns_snd (dns_connection *dns);
		509	~dns_snd ();
319	};	510	};
320		511
321	static u16 dns_id = 12098; // TODO: should be per-vpn	512	static u16 dns_id = 12098; // TODO: should be per-vpn
322		513
323	static u16 next_id ()	514	static u16 next_id ()
…		…
330	^ (dns_id >> 15)) & 1);	521	^ (dns_id >> 15)) & 1);
331		522
332	return dns_id;	523	return dns_id;
333	}	524	}
334		525
335	dns_req::dns_req (connection *c)	526	dns_snd::dns_snd (dns_connection *dns)
336	: conn (c)	527	: dns (dns)
337	{	528	{
338	next = 0;	529	timeout = 0;
339	retry = 0;	530	retry = 0;
		531	seqno = 0;
		532	sent = NOW;
340		533
341	pkt = new dns_packet;	534	pkt = new dns_packet;
342		535
343	pkt->id = next_id ();	536	pkt->id = next_id ();
344	}	537	}
345		538
		539	dns_snd::~dns_snd ()
		540	{
		541	delete pkt;
		542	}
		543
		544	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		545	{
		546	// add tunnel domain
		547	for (;;)
		548	{
		549	const char *end = strchr (domain, '.');
		550
		551	if (!end)
		552	end = domain + strlen (domain);
		553
		554	int len = end - domain;
		555
		556	pkt [offs++] = len;
		557	memcpy (pkt.at (offs), domain, len);
		558	offs += len;
		559
		560	if (!*end)
		561	break;
		562
		563	domain = end + 1;
		564	}
		565	}
		566
346	void dns_req::gen_stream_req (int seqno, byte_stream *stream)	567	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
347	{	568	{
348	this->seqno = seqno;	569	this->seqno = seqno;
		570
		571	timeout = NOW + INITIAL_TIMEOUT;
349		572
350	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	573	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
351	pkt->qdcount = htons (1);	574	pkt->qdcount = htons (1);
352		575
353	int offs = 6*2;	576	int offs = 6*2;
354	int dlen = MAX_DOMAIN_SIZE - strlen (THISNODE->domain) - 2;	577	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);
355	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	578	// 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	579	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
357		580
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;	581	char enc[256], *encp = enc;
370		582	encode_header (enc, THISNODE->id, seqno);
371	memcpy (data + 3, stream->begin (), datalen);	583
372	int enclen = dns64::encode (enc, data, datalen + 3);	584	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
		585
		586	if (datalen > stream.size ())
		587	datalen = stream.size ();
		588
		589	int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
373	stream->remove (datalen);	590	stream.remove (datalen);
374		591
375	while (enclen)	592	while (enclen)
376	{	593	{
377	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;	594	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
378		595
…		…
383	encp += lbllen;	600	encp += lbllen;
384		601
385	enclen -= lbllen;	602	enclen -= lbllen;
386	}	603	}
387		604
388	const char *suffix = THISNODE->domain;	605	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		606
410	(*pkt)[offs++] = 0;	607	(*pkt)[offs++] = 0;
411	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	608	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		609	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		610
		611	pkt->len = offs;
		612	}
		613
		614	void dns_snd::gen_syn_req (const dns_cfg &cfg)
		615	{
		616	timeout = NOW + INITIAL_SYN_TIMEOUT;
		617
		618	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		619	pkt->qdcount = htons (1);
		620
		621	int offs = 6*2;
		622
		623	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&cfg, sizeof (dns_cfg));
		624
		625	assert (elen <= MAX_LBL_SIZE);
		626
		627	(*pkt)[offs] = elen;
		628	offs += elen + 1;
		629	append_domain (*pkt, offs, THISNODE->domain);
		630
		631	(*pkt)[offs++] = 0;
		632	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
412	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	633	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
413		634
414	pkt->len = offs;	635	pkt->len = offs;
415	}	636	}
416		637
…		…
419	int seqno;	640	int seqno;
420	dns_packet *pkt; // reply packet	641	dns_packet *pkt; // reply packet
421	u8 data [MAXSIZE]; // actually part of the reply packet...	642	u8 data [MAXSIZE]; // actually part of the reply packet...
422	int datalen;	643	int datalen;
423		644
424	dns_rcv (int seqno, dns_packet req, u8 data, int datalen);	645	dns_rcv (int seqno, u8 *data, int datalen);
425	~dns_rcv ();	646	~dns_rcv ();
426	};	647	};
427		648
428	dns_rcv::dns_rcv (int seqno, dns_packet req, u8 data, int datalen)	649	dns_rcv::dns_rcv (int seqno, u8 *data, int datalen)
429	: seqno (seqno), pkt (new dns_packet), datalen (datalen)	650	: seqno (seqno), pkt (new dns_packet), datalen (datalen)
430	{	651	{
431	memcpy (this->data, data, datalen);	652	memcpy (this->data, data, datalen);
432	pkt->len = req->len;
433	memcpy (pkt->at (0), req->at (0), req->len);
434	}	653	}
435		654
436	dns_rcv::~dns_rcv ()	655	dns_rcv::~dns_rcv ()
437	{	656	{
438	delete pkt;	657	delete pkt;
439	}	658	}
440		659
441	/////////////////////////////////////////////////////////////////////////////	660	/////////////////////////////////////////////////////////////////////////////
442		661
443	struct dns_cfg	662	struct dns_connection
444	{	663	{
445	u8 id1, id2, id3;	664	connection *c;
446	u8 def_ttl;	665	struct vpn *vpn;
447	u8 unused1;	666
448	u16 max_size;	667	dns_cfg cfg;
449	u8 flags1, flags2;	668
		669	bool established;
		670
		671	tstamp last_received;
		672	tstamp last_sent;
		673	double poll_interval, send_interval;
		674
		675	vector<dns_rcv *> rcvpq;
		676
		677	byte_stream rcvdq; int rcvseq;
		678	byte_stream snddq; int sndseq;
		679
		680	void time_cb (time_watcher &w); time_watcher tw;
		681	void receive_rep (dns_rcv *r);
		682
		683	dns_connection (connection *c);
		684	~dns_connection ();
450	};	685	};
451		686
		687	dns_connection::dns_connection (connection *c)
		688	: c (c)
		689	, rcvdq (MAX_BACKLOG * 2)
		690	, snddq (MAX_BACKLOG * 2)
		691	, tw (this, &dns_connection::time_cb)
		692	{
		693	vpn = c->vpn;
		694
		695	established = false;
		696
		697	rcvseq = sndseq = 0;
		698
		699	last_sent = last_received = 0;
		700	poll_interval = MIN_POLL_INTERVAL;
		701	send_interval = 0.2; // starting rate
		702	}
		703
		704	dns_connection::~dns_connection ()
		705	{
		706	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		707	i != rcvpq.end ();
		708	++i)
		709	delete *i;
		710	}
		711
452	void connection::dnsv4_receive_rep (struct dns_rcv *r)	712	void dns_connection::receive_rep (dns_rcv *r)
453	{	713	{
		714	if (r->datalen)
		715	{
		716	last_received = NOW;
		717	tw.trigger ();
		718
		719	poll_interval = send_interval;
		720	}
		721	else
		722	{
		723	poll_interval *= 1.1;
		724	if (poll_interval > MAX_POLL_INTERVAL)
		725	poll_interval = MAX_POLL_INTERVAL;
		726	}
		727
454	dns_rcvpq.push_back (r);	728	rcvpq.push_back (r);
455		729
456	redo:	730	redo:
457		731
		732	// find next packet
458	for (vector<dns_rcv *>::iterator i = dns_rcvpq.begin ();	733	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
459	i != dns_rcvpq.end ();
460	++i)
461	if (dns_rcvseq == (*i)->seqno)	734	if (SEQNO_EQ (rcvseq, (*i)->seqno))
462	{	735	{
		736	// enter the packet into our input stream
463	dns_rcv r = i;	737	r = *i;
464		738
465	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;	739	// remove the oldest packet, look forward, as it's oldest first
466		740	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
467	if (!dns_snddq && !dns_rcvdq)	741	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
468	{	742	{
469	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);	743	delete *j;
470	dns_snddq = new byte_stream (MAX_BACKLOG);	744	rcvpq.erase (j);
471		745	break;
472	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
473	}	746	}
474		747
		748	rcvseq = (rcvseq + 1) & SEQNO_MASK;
		749
475	if (!dns_rcvdq->put (r->data, r->datalen))	750	if (!rcvdq.put (r->data, r->datalen))
476	abort (); // MUST never overflow, can be caused by data corruption, TODO	751	abort (); // MUST never overflow, can be caused by data corruption, TODO
477		752
478	while (vpn_packet *pkt = dns_rcvdq->get ())	753	while (vpn_packet *pkt = rcvdq.get ())
479	{	754	{
480	sockinfo si;	755	sockinfo si;
481	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	756	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;
482		757
483	vpn->recv_vpn_packet (pkt, si);	758	vpn->recv_vpn_packet (pkt, si);
		759
		760	delete pkt;
484	}	761	}
485	}	762
486	else if ((u32)dns_rcvseq - MAX_WINDOW - (u32)(i)->seqno < MAX_WINDOW 2)	763	// check for further packets
487	{
488	dns_rcvpq.erase (i);
489	goto redo;	764	goto redo;
490	}	765	}
491	}	766	}
492		767
493	dns_packet *	768	void
494	vpn::dnsv4_server (dns_packet *pkt)	769	vpn::dnsv4_server (dns_packet &pkt)
495	{	770	{
496	u16 flags = ntohs (pkt->flags);	771	u16 flags = ntohs (pkt.flags);
497		772
498	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
499	int offs = 6 * 2; // skip header	773	int offs = 6 * 2; // skip header
500		774
501	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	775	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
502		776
503	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	777	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
504	&& pkt->qdcount == htons (1))	778	&& pkt.qdcount == htons (1))
505	{	779	{
506	char qname[MAXSIZE];	780	char qname[MAXSIZE];
507	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	781	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
508		782
509	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	783	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
510	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	784	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
511		785
512	pkt->qdcount = htons (1);	786	pkt.qdcount = htons (1);
513	pkt->ancount = 0;	787	pkt.ancount = 0;
514	pkt->nscount = 0; // should be self, as other nameservers reply like this	788	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	789	pkt.arcount = 0; // a record for self, as other nameservers reply like this
516		790
517	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	791	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);
518		792
519	int dlen = strlen (THISNODE->domain);	793	int dlen = strlen (THISNODE->domain);
520		794
521	if (qclass == RR_CLASS_IN	795	if (qclass == RR_CLASS_IN
522	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
523	&& qlen > dlen + 1	796	&& qlen > dlen + 1
524	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	797	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
525	{	798	{
526	// correct class, domain: parse	799	// now generate reply
527	u8 data[MAXSIZE];	800	pkt.ancount = htons (1); // one answer RR
528	int datalen = dns64::decode (data, qname, qlen - dlen - 1);	801	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
529		802
530	int client = data[0];	803	if ((qtype == RR_TYPE_ANY
531	int seqno = ((data[1] << 8) \| data[2]) & SEQNO_MASK;	804	\|\| qtype == RR_TYPE_TXT
532		805	\|\| qtype == RR_TYPE_NULL)
533	if (0 < client && client <= conns.size ())	806	&& qlen > dlen + 1 + HDRSIZE)
534	{	807	{
535	connection *c = conns [client - 1];	808	// correct class, domain: parse
		809	int client, seqno;
		810	decode_header (qname, client, seqno);
536		811
537	for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.begin ();	812	u8 data[MAXSIZE];
538	i != c->dns_rcvpq.end ();	813	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		814
545	offs = r->pkt->len;	815	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	{	816	{
		817	connection *c = conns [client - 1];
		818	dns_connection *dns = c->dns;
		819	dns_rcv *rcv;
		820
		821	if (dns)
		822	{
		823	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
		824	if (SEQNO_EQ ((*i)->seqno, seqno))
		825	{
		826	// already seen that request: simply reply with the cached reply
		827	dns_rcv r = i;
		828
		829	slog (L_DEBUG, "DUPLICATE %d\n", htons (r->pkt->id));
		830
		831	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		832	pkt.id = r->pkt->id;
		833	goto duplicate_request;
		834	}
		835
		836	// new packet, queue
		837	rcv = new dns_rcv (seqno, data, datalen);
		838	dns->receive_rep (rcv);
		839	}
		840
		841	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		842
		843	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		844	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		845	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		846	pkt [offs++] = 0; pkt [offs++] = 0;
		847	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
		848
		849	int rdlen_offs = offs += 2;
		850
		851	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
		852	// bind doesn't compress well, so reduce further by one label length
		853	dlen -= qlen;
		854
		855	if (dns)
		856	{
		857	while (dlen > 1 && !dns->snddq.empty ())
		858	{
577	int txtlen = dlen <= 255 ? dlen - 1 : 255;	859	int txtlen = dlen <= 255 ? dlen - 1 : 255;
578		860
579	if (txtlen > c->dns_snddq->size ())	861	if (txtlen > dns->snddq.size ())
580	txtlen = c->dns_snddq->size ();	862	txtlen = dns->snddq.size ();
581		863
582	(*pkt)[offs++] = txtlen;	864	pkt[offs++] = txtlen;
583	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);	865	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
584	offs += txtlen;	866	offs += txtlen;
585	c->dns_snddq->remove (txtlen);	867	dns->snddq.remove (txtlen);
586		868
587	dlen -= txtlen + 1;	869	dlen -= txtlen + 1;
		870	}
		871
		872	// avoid empty TXT rdata
		873	if (offs == rdlen_offs)
		874	pkt[offs++] = 0;
		875
		876	slog (L_NOISE, "snddq %d", dns->snddq.size ());
		877	}
		878	else
		879	{
		880	// send RST
		881	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		882	pkt [offs++] = CMD_IP_RST;
		883	}
		884
		885	int rdlen = offs - rdlen_offs;
		886
		887	pkt [rdlen_offs - 2] = rdlen >> 8;
		888	pkt [rdlen_offs - 1] = rdlen;
		889
		890	if (dns)
		891	{
		892	// now update dns_rcv copy
		893	rcv->pkt->len = offs;
		894	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		895	}
		896
		897	duplicate_request: ;
588	}	898	}
589		899	else
590	// avoid empty TXT rdata	900	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	}	901	}
601	else	902	else if (qtype == RR_TYPE_A
602	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	903	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		904	{
		905	dns_cfg cfg;
		906	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		907	int client = ntohs (cfg.client);
		908
		909	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		910
		911	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
		912	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		913	pkt [offs++] = 0; pkt [offs++] = 0;
		914	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		915	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
		916
		917	slog (L_INFO, _("DNS tunnel: client %d tries to connect"), client);
		918
		919	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		920	pkt [offs++] = CMD_IP_REJ;
		921
		922	if (0 < client && client <= conns.size ())
		923	{
		924	connection *c = conns [client - 1];
		925
		926	if (cfg.valid ())
		927	{
		928	pkt [offs - 1] = CMD_IP_SYN;
		929
		930	delete c->dns;
		931	c->dns = new dns_connection (c);
		932	c->dns->cfg = cfg;
		933	}
		934	}
		935	}
603	}	936	}
604	}
605	else
606	offs = pkt->len;
607		937
608	pkt->len = offs;	938	pkt.len = offs;
609	return pkt;	939	}
610	}	940	}
611		941
612	void	942	void
613	vpn::dnsv4_client (dns_packet *pkt)	943	vpn::dnsv4_client (dns_packet &pkt)
614	{	944	{
615	u16 flags = ntohs (pkt->flags);	945	u16 flags = ntohs (pkt.flags);
616	int offs = 6 * 2; // skip header	946	int offs = 6 * 2; // skip header
617		947
618	pkt->qdcount = ntohs (pkt->qdcount);	948	pkt.qdcount = ntohs (pkt.qdcount);
619	pkt->ancount = ntohs (pkt->ancount);	949	pkt.ancount = ntohs (pkt.ancount);
620		950
621	// go through our request list and find the corresponding request	951	// go through our request list and find the corresponding request
622	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	952	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
623	i != dns_sndpq.end ();	953	i != dns_sndpq.end ();
624	++i)	954	++i)
625	if ((*i)->pkt->id == pkt->id)	955	if ((*i)->pkt->id == pkt.id)
626	{	956	{
		957	dns_connection dns = (i)->dns;
627	connection c = (i)->conn;	958	connection *c = dns->c;
628	int seqno = (*i)->seqno;	959	int seqno = (*i)->seqno;
629	u8 data[MAXSIZE], *datap = data;	960	u8 data[MAXSIZE], *datap = data;
630		961
		962	if ((*i)->retry)
		963	{
		964	dns->send_interval *= 1.001;
		965	if (dns->send_interval > MAX_SEND_INTERVAL)
		966	dns->send_interval = MAX_SEND_INTERVAL;
		967	}
		968	else
		969	{
		970	#if 1
		971	dns->send_interval *= 0.9999;
		972	#endif
		973	if (dns->send_interval < MIN_SEND_INTERVAL)
		974	dns->send_interval = MIN_SEND_INTERVAL;
		975
		976	// the latency surely puts an upper bound on
		977	// the minimum send interval
		978	double latency = NOW - (*i)->sent;
		979
		980	if (dns->send_interval > latency)
		981	dns->send_interval = latency;
		982	}
		983
631	delete *i;	984	delete *i;
632	dns_sndpq.erase (i);	985	dns_sndpq.erase (i);
633		986
634	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	987	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
635	{	988	{
636	char qname[MAXSIZE];	989	char qname[MAXSIZE];
637		990
638	while (pkt->qdcount-- && offs < MAXSIZE - 4)	991	while (pkt.qdcount-- && offs < MAXSIZE - 4)
639	{	992	{
640	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	993	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
641	offs += 4; // skip qtype, qclass	994	offs += 4; // skip qtype, qclass
642	}	995	}
643		996
644	while (pkt->ancount-- && offs < MAXSIZE - 10)	997	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
645	{	998	{
646	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	999	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
647		1000
648	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1001	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
649	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1002	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
650	u32 ttl = (*pkt) [offs++] << 24;	1003	u32 ttl = pkt [offs++] << 24;
651	ttl \|= (*pkt) [offs++] << 16;	1004	ttl \|= pkt [offs++] << 16;
652	ttl \|= (*pkt) [offs++] << 8;	1005	ttl \|= pkt [offs++] << 8;
653	ttl \|= (*pkt) [offs++];	1006	ttl \|= pkt [offs++];
654
655	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1007	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
656		1008
657	if (rdlen <= MAXSIZE - offs)	1009	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
658	{	1010	{
659	// decode bytes, finally	1011	if (rdlen <= MAXSIZE - offs)
660
661	while (rdlen)
662	{	1012	{
		1013	// decode bytes, finally
		1014
		1015	while (rdlen)
		1016	{
663	int txtlen = (*pkt) [offs++];	1017	int txtlen = pkt [offs++];
664		1018
665	assert (txtlen + offs < MAXSIZE - 1);	1019	assert (txtlen + offs < MAXSIZE - 1);
666		1020
667	memcpy (datap, pkt->at (offs), txtlen);	1021	memcpy (datap, pkt.at (offs), txtlen);
668	datap += txtlen; offs += txtlen;	1022	datap += txtlen; offs += txtlen;
669		1023
670	rdlen -= txtlen + 1;	1024	rdlen -= txtlen + 1;
		1025	}
671	}	1026	}
672
673	}	1027	}
		1028	else if (qtype == RR_TYPE_A)
		1029	{
		1030	u8 ip [4];
674		1031
		1032	ip [0] = pkt [offs++];
		1033	ip [1] = pkt [offs++];
		1034	ip [2] = pkt [offs++];
		1035	ip [3] = pkt [offs++];
		1036
		1037	if (ip [0] == CMD_IP_1
		1038	&& ip [1] == CMD_IP_2
		1039	&& ip [2] == CMD_IP_3)
		1040	{
		1041	slog (L_TRACE, _("got tunnel meta command %02x"), ip [3]);
		1042
		1043	if (ip [3] == CMD_IP_RST)
		1044	{
		1045	slog (L_DEBUG, _("got tunnel RST request"));
		1046
		1047	delete dns; c->dns = 0;
		1048
		1049	return;
		1050	}
		1051	else if (ip [3] == CMD_IP_SYN)
		1052	{
		1053	slog (L_DEBUG, _("got tunnel SYN reply, server likes us."));
		1054	dns->established = true;
		1055	}
		1056	else if (ip [3] == CMD_IP_REJ)
		1057	{
		1058	slog (L_DEBUG, _("got tunnel REJ reply, server does not like us, aborting."));
		1059	abort ();
		1060	}
		1061	else
		1062	slog (L_INFO, _("got unknown meta command %02x"), ip [3]);
		1063	}
		1064	else
		1065	slog (L_INFO, _("got spurious a record %d.%d.%d.%d"),
		1066	ip [0], ip [1], ip [2], ip [3]);
		1067
		1068	return;
		1069	}
		1070
		1071	int client, rseqno;
		1072	decode_header (qname, client, rseqno);
		1073
		1074	if (client != THISNODE->id)
		1075	{
		1076	slog (L_INFO, _("got dns tunnel response with wrong clientid, ignoring"));
		1077	datap = 0;
		1078	}
		1079	else if (rseqno != seqno)
		1080	{
		1081	slog (L_DEBUG, _("got dns tunnel response with wrong seqno, badly caching nameserver?"));
		1082	datap = 0;
		1083	}
675	}	1084	}
676	}	1085	}
677		1086
		1087	// todo: pkt now used
678	if (datap != data)	1088	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));	1089	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
687		1090
688	break;	1091	break;
689	}	1092	}
690
691	delete pkt;
692	}	1093	}
693		1094
694	void	1095	void
695	vpn::dnsv4_ev (io_watcher &w, short revents)	1096	vpn::dnsv4_ev (io_watcher &w, short revents)
696	{	1097	{
…		…
698	{	1099	{
699	dns_packet *pkt = new dns_packet;	1100	dns_packet *pkt = new dns_packet;
700	struct sockaddr_in sa;	1101	struct sockaddr_in sa;
701	socklen_t sa_len = sizeof (sa);	1102	socklen_t sa_len = sizeof (sa);
702		1103
703	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1104	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
704		1105
705	if (pkt->len > 0)	1106	if (pkt->len > 0)
706	{	1107	{
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)	1108	if (THISNODE->dns_port)
714	{	1109	{
715	pkt = dnsv4_server (pkt);	1110	dnsv4_server (*pkt);
716	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);	1111	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
717	}	1112	}
718	else	1113	else
719	dnsv4_client (pkt);	1114	dnsv4_client (*pkt);
		1115
		1116	delete pkt;
720	}	1117	}
721	}	1118	}
722	}	1119	}
723		1120
724	bool	1121	bool
725	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1122	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
726	{	1123	{
727	// never initialized	1124	if (!dns)
728	if (!dns_snddq && !dns_rcvdq)	1125	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		1126
738	if (!dns_snddq->put (pkt))	1127	if (!dns->snddq.put (pkt))
739	return false;	1128	return false;
740		1129
741	// start timer if neccessary	1130	dns->tw.trigger ();
742	if (!THISNODE->dns_port && !dnsv4_tw.active)
743	dnsv4_cb (dnsv4_tw);
744		1131
745	return true;	1132	return true;
746	}	1133	}
747		1134
748	void	1135	void
		1136	connection::dnsv4_reset_connection ()
		1137	{
		1138	//delete dns; dns = 0; //TODO
		1139	}
		1140
		1141	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1142
		1143	void
749	connection::dnsv4_cb (time_watcher &w)	1144	dns_connection::time_cb (time_watcher &w)
750	{	1145	{
		1146	// servers have to be polled
		1147	if (THISNODE->dns_port)
		1148	return;
		1149
751	// check for timeouts and (re)transmit	1150	// check for timeouts and (re)transmit
752	tstamp next = NOW + 60;	1151	tstamp next = NOW + poll_interval;
753	dns_req *send = 0;	1152	dns_snd *send = 0;
754		1153
755	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1154	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
756	i != vpn->dns_sndpq.end ();	1155	i != vpn->dns_sndpq.end ();
757	++i)	1156	++i)
758	{	1157	{
759	dns_req r = i;	1158	dns_snd r = i;
760		1159
761	if (r->next <= NOW)	1160	if (r->timeout <= NOW)
762	{	1161	{
763	if (!send)	1162	if (!send)
764	{	1163	{
765	send = r;	1164	send = r;
766		1165
767	if (r->retry)//D
768	printf ("req %d, retry %d\n", r->pkt->id, r->retry);
769	r->retry++;	1166	r->retry++;
770	r->next = NOW + r->retry;	1167	r->timeout = NOW + r->retry;
771	}	1168	}
772	}	1169	}
		1170	else
		1171	NEXT (r->timeout);
		1172	}
773		1173
774	if (r->next < next)	1174	if (last_sent + send_interval <= NOW)
775	next = r->next;
776	}	1175	{
777
778	if (!send	1176	if (!send)
		1177	{
		1178	// generate a new packet, if wise
		1179
		1180	if (!established)
		1181	{
		1182	if (vpn->dns_sndpq.empty ())
		1183	{
		1184	send = new dns_snd (this);
		1185
		1186	cfg.reset (THISNODE->id);
		1187	send->gen_syn_req (cfg);
		1188	}
		1189	}
779	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)	1190	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
780	{	1191	{
781	send = new dns_req (this);	1192	send = new dns_snd (this);
782	send->gen_stream_req (dns_sndseq, dns_snddq);	1193	send->gen_stream_req (sndseq, snddq);
		1194
		1195	sndseq = (sndseq + 1) & SEQNO_MASK;
		1196	}
		1197
		1198	if (send)
783	vpn->dns_sndpq.push_back (send);	1199	vpn->dns_sndpq.push_back (send);
		1200	}
784		1201
785	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
786	}
787
788	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
789
790	if (send)	1202	if (send)
		1203	{
		1204	last_sent = NOW;
		1205	sendto (vpn->dnsv4_fd,
		1206	send->pkt->at (0), send->pkt->len, 0,
		1207	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
		1208	}
791	{	1209	}
792	dns_packet *pkt = send->pkt;	1210	else
		1211	NEXT (last_sent + send_interval);
793		1212
794	next = min_next;	1213	slog (L_NOISE, "pi %f si %f N %f (%d:%d)",
		1214	poll_interval, send_interval, next - NOW,
		1215	vpn->dns_sndpq.size (), snddq.size ());
795		1216
796	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0, dns_si.sav4 (), dns_si.salenv4 ());	1217	// TODO: no idea when this happens, but when next < NOW, we have a problem
797	}	1218	if (next < NOW + 0.0001)
798	else if (next < min_next)	1219	next = NOW + 0.1;
799	next = min_next;
800		1220
801	w.start (next);	1221	w.start (next);
802	}	1222	}
803		1223
804	#endif	1224	#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 1.15 by pcg, Fri Mar 4 10:15:45 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 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC