[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 1.15 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.
46		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?
		57
47	#define MAX_OUTSTANDING 10 // 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 1 // requests/s
50	#define MAX_BACKLOG (10*1024) // size of protocol backlog	60	#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
51		61
52	/*	62	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well
		63	// 240 leaves about 4 bytes of server reply data
		64	// every two request bytes less give room for one reply byte
53		65
54	protocol, in shorthand :)	66	#define SEQNO_MASK 0xffff
55		67	#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		68
68	#define MAX_LBL_SIZE 63	69	#define MAX_LBL_SIZE 63
69	#define MAX_PKT_SIZE 512	70	#define MAX_PKT_SIZE 512
70		71
		72	#define RR_TYPE_A 1
		73	#define RR_TYPE_NULL 10
71	#define RR_TYPE_TXT 16	74	#define RR_TYPE_TXT 16
72	#define RR_TYPE_ANY 255	75	#define RR_TYPE_ANY 255
		76
73	#define RR_CLASS_IN 1	77	#define RR_CLASS_IN 1
74		78
75	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)	79	#define CMD_IP_1 207
76	struct dns64	80	#define CMD_IP_2 46
77	{	81	#define CMD_IP_3 236
78	static const char encode_chars[64 + 1];	82	#define CMD_IP_RST 29
79	static s8 decode_chars[256];	83	#define CMD_IP_SYN 113
		84	#define CMD_IP_REJ 32
80		85
81	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }	86	// works for cmaps up to 255 (not 256!)
82	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
83	static int encode (char dst, u8 src, int len);	129	unsigned int encode (char dst, u8 src, unsigned int len);
84	static int decode (u8 dst, char src, int len);	130	unsigned int decode (u8 dst, char src, unsigned int len);
85		131
86	dns64 ();	132	basecoder (const char *cmap);
87	} dns64;	133	};
88		134
89	const char dns64::encode_chars[64 + 1] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-";	135	basecoder::basecoder (const char *cmap)
90	s8 dns64::decode_chars[256];	136	: cmap (cmap)
91
92	dns64::dns64 ()
93	{	137	{
94	for (int i = 0; i < 64; i++)	138	for (unsigned int len = 0; len < MAX_DEC_LEN; ++len)
95	decode_chars [encode_chars [i]] = i + 1;	139	{
96	}	140	u8 src [MAX_DEC_LEN];
		141	u8 dst [MAX_ENC_LEN];
97		142
98	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)
99	{	160	{
100	// slow, but easy to debug	161	return enc_len [len];
101	char *beg = dst;	162	}
102	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;
103		208
104	while (len--)	209	while (len--)
105	{	210	{
106	accum <<= 8;	211	u8 val = cmap.decode [(u8)*src++];
107	accum \|= *src++;
108	bits += 8;
109		212
110	while (bits >= 6)	213	if (val != charmap::INVALID)
111	{	214	src_ [elen++] = val;
112	*dst++ = encode_chars [(accum >> (bits - 6)) & 63];	215	}
113	bits -= 6;	216
114	}	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)
115	}	228	{
		229	memset (dst, 0, dlen - n);
		230	memcpy (dst + dlen - n, dst_, n);
		231	}
		232	else
		233	memcpy (dst, dst_ + n - dlen, dlen);
116		234
117	if (bits)	235	return dlen;
118	*dst++ = encode_chars [(accum << (6 - bits)) & 63];
119
120	return dst - beg;
121	}	236	}
122		237
123	int dns64::decode (u8 dst, char src, int len)	238	#if 0
124	{	239	struct test { test (); } test;
125	// slow, but easy to debug
126	u8 *beg = dst;
127	unsigned int accum, bits = 0;
128		240
129	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++)
130	{	250	{
131	s8 chr = decode_chars [(u8)*src++];	251	int elen = cdc.encode (enc, in, i);
		252	int dlen = cdc.decode (dec, enc, elen);
132		253
133	if (!chr)	254	printf ("%d>%d>%d (%s>%s)\n", i, elen, dlen, enc, dec);
134	break;
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	}	255	}
		256	abort ();
		257	}
		258	#endif
146		259
147	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];
148	}	287	}
149		288
150	/////////////////////////////////////////////////////////////////////////////	289	/////////////////////////////////////////////////////////////////////////////
151		290
152	struct byte_stream	291	struct byte_stream
…		…
159	~byte_stream ();	298	~byte_stream ();
160		299
161	bool empty () { return !fill; }	300	bool empty () { return !fill; }
162	int size () { return fill; }	301	int size () { return fill; }
163		302
		303	bool put (u8 *data, unsigned int datalen);
164	bool put (vpn_packet *pkt);	304	bool put (vpn_packet *pkt);
165	vpn_packet *get ();	305	vpn_packet *get ();
166		306
167	u8 *begin () { return data; }	307	u8 *begin () { return data; }
168	void remove (int count);	308	void remove (int count);
…		…
185	abort ();	325	abort ();
186		326
187	memmove (data, data + count, fill -= count);	327	memmove (data, data + count, fill -= count);
188	}	328	}
189		329
		330	bool byte_stream::put (u8 *data, unsigned int datalen)
		331	{
		332	if (maxsize - fill < datalen)
		333	return false;
		334
		335	memcpy (this->data + fill, data, datalen); fill += datalen;
		336
		337	return true;
		338	}
		339
190	bool byte_stream::put (vpn_packet *pkt)	340	bool byte_stream::put (vpn_packet *pkt)
191	{	341	{
192	if (maxsize - fill < pkt->len + 2)	342	if (maxsize - fill < pkt->len + 2)
193	return false;	343	return false;
194		344
195	data [fill++] = pkt->len >> 8;	345	data [fill++] = pkt->len >> 8;
196	data [fill++] = pkt->len;	346	data [fill++] = pkt->len;
197		347
198	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	348	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
199		349
200	return true;	350	return true;
201	}	351	}
202		352
203	vpn_packet *byte_stream::get ()	353	vpn_packet *byte_stream::get ()
204	{	354	{
205	int len = (data [0] << 8) \| data [1];	355	unsigned int len = (data [0] << 8) \| data [1];
		356
		357	if (len > MAXSIZE && fill >= 2)
		358	abort (); // TODO handle this gracefully, connection reset
206		359
207	if (fill < len + 2)	360	if (fill < len + 2)
208	return 0;	361	return 0;
209		362
210	vpn_packet *pkt = new vpn_packet;	363	vpn_packet *pkt = new vpn_packet;
		364
		365	pkt->len = len;
211	memcpy (&((*pkt)[0]), data + 2, len);	366	memcpy (pkt->at (0), data + 2, len);
212	remove (len + 2);	367	remove (len + 2);
213		368
214	return pkt;	369	return pkt;
215	}	370	}
216		371
217	/////////////////////////////////////////////////////////////////////////////	372	/////////////////////////////////////////////////////////////////////////////
218		373
219	#define FLAG_QUERY ( 0 << 15)	374	#define FLAG_QUERY ( 0 << 15)
220	#define FLAG_RESPONSE ( 1 << 15)	375	#define FLAG_RESPONSE ( 1 << 15)
221	#define FLAG_OP_MASK (15 << 14)	376	#define FLAG_OP_MASK (15 << 11)
222	#define FLAG_OP_QUERY ( 0 << 11)	377	#define FLAG_OP_QUERY ( 0 << 11)
223	#define FLAG_AA ( 1 << 10)	378	#define FLAG_AA ( 1 << 10)
224	#define FLAG_TC ( 1 << 9)	379	#define FLAG_TC ( 1 << 9)
225	#define FLAG_RD ( 1 << 8)	380	#define FLAG_RD ( 1 << 8)
226	#define FLAG_RA ( 1 << 7)	381	#define FLAG_RA ( 1 << 7)
		382	#define FLAG_AUTH ( 1 << 5)
227	#define FLAG_RCODE_MASK (15 << 0)	383	#define FLAG_RCODE_MASK (15 << 0)
228	#define FLAG_RCODE_OK ( 0 << 0)	384	#define FLAG_RCODE_OK ( 0 << 0)
229	#define FLAG_RCODE_FORMERR ( 1 << 0)	385	#define FLAG_RCODE_FORMERR ( 1 << 0)
230	#define FLAG_RCODE_SERVFAIL ( 2 << 0)	386	#define FLAG_RCODE_SERVFAIL ( 2 << 0)
231	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)	387	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)
232	#define FLAG_RCODE_REFUSED ( 5 << 0)	388	#define FLAG_RCODE_REFUSED ( 5 << 0)
233		389
234	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	390	#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)	391	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
		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	}
236		449
237	struct dns_packet : net_packet	450	struct dns_packet : net_packet
238	{	451	{
239	u16 id;	452	u16 id;
240	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
…		…
279	return data - orig;	492	return data - orig;
280	}	493	}
281		494
282	/////////////////////////////////////////////////////////////////////////////	495	/////////////////////////////////////////////////////////////////////////////
283		496
284	struct dns_req	497	struct dns_snd
285	{	498	{
286	dns_packet *pkt;	499	dns_packet *pkt;
287	tstamp next;	500	tstamp timeout, sent;
288	int retry;	501	int retry;
289	connection *conn;	502	struct dns_connection *dns;
		503	int seqno;
290		504
291	dns_req (connection c, 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 ();
292	};	510	};
293		511
294	struct dns_rep
295	{
296	};
297
298	static u16 dns_id; // TODO: should be per-vpn	512	static u16 dns_id = 12098; // TODO: should be per-vpn
299		513
300	dns_req::dns_req (connection c, int seqno, byte_stream stream)	514	static u16 next_id ()
301	: conn (c)
302	{	515	{
303	next = 0;	516	// the simplest lsfr with periodicity 65535 i could find
		517	dns_id = (dns_id << 1)
		518	\| (((dns_id >> 1)
		519	^ (dns_id >> 2)
		520	^ (dns_id >> 4)
		521	^ (dns_id >> 15)) & 1);
		522
		523	return dns_id;
		524	}
		525
		526	dns_snd::dns_snd (dns_connection *dns)
		527	: dns (dns)
		528	{
		529	timeout = 0;
304	retry = 0;	530	retry = 0;
		531	seqno = 0;
		532	sent = NOW;
305		533
306	pkt = new dns_packet;	534	pkt = new dns_packet;
307		535
308	pkt->id = dns_id++;	536	pkt->id = next_id ();
309	pkt->flags = DEFAULT_CLIENT_FLAGS;	537	}
310	pkt->qdcount = htons (1);
311	pkt->ancount = 0;
312	pkt->nscount = 0;
313	pkt->arcount = 0;
314		538
315	int offs = 6*2;	539	dns_snd::~dns_snd ()
316	int dlen = 255 - strlen (THISNODE->domain) - 1; // here we always have room for the max. label length	540	{
		541	delete pkt;
		542	}
317		543
318	u8 lbl[64]; //D	544	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
319	char enc[65];	545	{
320	int lbllen = 3;
321	lbl[0] = c->conf->id; //D
322	lbl[1] = seqno >> 8; //D
323	lbl[2] = seqno; //D
324
325	while (dlen > 0)
326	{
327	int sndlen = dlen;
328
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 ())
333	sndlen = stream->size ();
334
335	if (sndlen + lbllen == 0)
336	break;
337
338	memcpy (lbl + lbllen, stream->begin (), sndlen);
339	stream->remove (sndlen);
340	lbllen += sndlen;
341
342	dns64::encode (enc, lbl, lbllen);
343
344	int elen = dns64::encode_len (lbllen);
345	(*pkt)[offs++] = elen;
346	memcpy (&((*pkt)[offs]), enc, elen);
347	offs += elen;
348	dlen -= elen + 1;
349
350	lbllen = 0;
351	}
352
353	const char *suffix = THISNODE->domain;
354
355	// add tunnel domain	546	// add tunnel domain
356	for (;;)	547	for (;;)
357	{	548	{
358	const char *end = strchr (suffix, '.');	549	const char *end = strchr (domain, '.');
359		550
360	if (!end)	551	if (!end)
361	end = suffix + strlen (suffix);	552	end = domain + strlen (domain);
362		553
363	int len = end - suffix;	554	int len = end - domain;
364		555
365	(*pkt)[offs++] = len;	556	pkt [offs++] = len;
366	memcpy (&((*pkt)[offs]), suffix, len);	557	memcpy (pkt.at (offs), domain, len);
367	offs += len;	558	offs += len;
368		559
369	if (!*end)	560	if (!*end)
370	break;	561	break;
371		562
372	suffix = end + 1;	563	domain = end + 1;
		564	}
		565	}
		566
		567	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
		568	{
		569	this->seqno = seqno;
		570
		571	timeout = NOW + INITIAL_TIMEOUT;
		572
		573	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		574	pkt->qdcount = htons (1);
		575
		576	int offs = 6*2;
		577	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);
		578	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
		579	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
		580
		581	char enc[256], *encp = enc;
		582	encode_header (enc, THISNODE->id, seqno);
		583
		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;
		590	stream.remove (datalen);
		591
		592	while (enclen)
373	}	593	{
		594	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
		595
		596	(*pkt)[offs++] = lbllen;
		597	memcpy (pkt->at (offs), encp, lbllen);
		598
		599	offs += lbllen;
		600	encp += lbllen;
		601
		602	enclen -= lbllen;
		603	}
		604
		605	append_domain (*pkt, offs, THISNODE->domain);
374		606
375	(*pkt)[offs++] = 0;	607	(*pkt)[offs++] = 0;
376	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	608	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
377	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	609	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
378		610
379	pkt->len = offs;	611	pkt->len = offs;
		612	}
380		613
381	c->vpn->dns_sndpq.push_back (this);	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;
		633	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		634
		635	pkt->len = offs;
		636	}
		637
		638	struct dns_rcv
		639	{
		640	int seqno;
		641	dns_packet *pkt; // reply packet
		642	u8 data [MAXSIZE]; // actually part of the reply packet...
		643	int datalen;
		644
		645	dns_rcv (int seqno, u8 *data, int datalen);
		646	~dns_rcv ();
		647	};
		648
		649	dns_rcv::dns_rcv (int seqno, u8 *data, int datalen)
		650	: seqno (seqno), pkt (new dns_packet), datalen (datalen)
		651	{
		652	memcpy (this->data, data, datalen);
		653	}
		654
		655	dns_rcv::~dns_rcv ()
		656	{
		657	delete pkt;
382	}	658	}
383		659
384	/////////////////////////////////////////////////////////////////////////////	660	/////////////////////////////////////////////////////////////////////////////
385		661
386	struct dns_cfg	662	struct dns_connection
387	{	663	{
388	u8 id1, id2, id3;	664	connection *c;
389	u8 def_ttl;	665	struct vpn *vpn;
390	u8 unused1;	666
391	u16 max_size;	667	dns_cfg cfg;
392	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 ();
393	};	685	};
394		686
395	dns_packet *	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
		712	void dns_connection::receive_rep (dns_rcv *r)
		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
		728	rcvpq.push_back (r);
		729
		730	redo:
		731
		732	// find next packet
		733	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
		734	if (SEQNO_EQ (rcvseq, (*i)->seqno))
		735	{
		736	// enter the packet into our input stream
		737	r = *i;
		738
		739	// remove the oldest packet, look forward, as it's oldest first
		740	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
		741	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
		742	{
		743	delete *j;
		744	rcvpq.erase (j);
		745	break;
		746	}
		747
		748	rcvseq = (rcvseq + 1) & SEQNO_MASK;
		749
		750	if (!rcvdq.put (r->data, r->datalen))
		751	abort (); // MUST never overflow, can be caused by data corruption, TODO
		752
		753	while (vpn_packet *pkt = rcvdq.get ())
		754	{
		755	sockinfo si;
		756	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;
		757
		758	vpn->recv_vpn_packet (pkt, si);
		759
		760	delete pkt;
		761	}
		762
		763	// check for further packets
		764	goto redo;
		765	}
		766	}
		767
		768	void
396	vpn::dnsv4_server (dns_packet *pkt)	769	vpn::dnsv4_server (dns_packet &pkt)
397	{	770	{
398	u16 flags = ntohs (pkt->flags);	771	u16 flags = ntohs (pkt.flags);
399		772
400	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
401	int offs = 6 * 2; // skip header	773	int offs = 6 * 2; // skip header
402		774
403	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	775	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
404		776
405	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	777	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
406	&& pkt->qdcount == htons (1))	778	&& pkt.qdcount == htons (1))
407	{	779	{
408	char qname[MAXSIZE];	780	char qname[MAXSIZE];
409	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	781	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
410		782
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
414	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	783	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
415	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	784	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
416		785
417	pkt->qdcount = htons (1);	786	pkt.qdcount = htons (1);
418	pkt->ancount = 0;	787	pkt.ancount = 0;
419	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
420	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
421		790
422	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	791	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);
423		792
424	int dlen = strlen (THISNODE->domain);	793	int dlen = strlen (THISNODE->domain);
425		794
426	if (qclass == RR_CLASS_IN	795	if (qclass == RR_CLASS_IN
427	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
428	&& qlen > dlen + 1	796	&& qlen > dlen + 1
429	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	797	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
430	{	798	{
431	// correct class, domain, parse
432	u8 data[MAXSIZE];
433	int datalen = dns64::decode (data, qname, qlen - dlen - 1);
434
435	for (int i = 0; i < datalen; i++)
436	printf ("%02x ", data[i]);
437	printf ("\n");
438
439
440
441
442	#if 0
443	// now generate reply	799	// now generate reply
444	rep->ancount = htons (1); // one answer RR	800	pkt.ancount = htons (1); // one answer RR
445	rep->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	801	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
446		802
447	(*rep) [offs++] = 0xc0;	803	if ((qtype == RR_TYPE_ANY
448	(rep) [offs++] = 6 2; // same as in query section	804	\|\| qtype == RR_TYPE_TXT
449		805	\|\| qtype == RR_TYPE_NULL)
450	(rep) [offs++] = RR_TYPE_TXT >> 8; (rep) [offs++] = RR_TYPE_TXT;	806	&& qlen > dlen + 1 + HDRSIZE)
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	{	807	{
470	int sndlen = --dlen;	808	// correct class, domain: parse
		809	int client, seqno;
		810	decode_header (qname, client, seqno);
471		811
472	if (sndlen + txtlen > 255)	812	u8 data[MAXSIZE];
473	sndlen = 255 - txtlen;	813	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
474		814
		815	if (0 < client && client <= conns.size ())
		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
475	sndlen = 0;	853	dlen -= qlen;
476		854
477	(*rep)[offs++] = sndlen + txtlen;	855	if (dns)
478	memcpy (&((*rep)[offs]), txt, txtlen);	856	{
		857	while (dlen > 1 && !dns->snddq.empty ())
		858	{
		859	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		860
		861	if (txtlen > dns->snddq.size ())
		862	txtlen = dns->snddq.size ();
		863
		864	pkt[offs++] = txtlen;
		865	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
479	offs += txtlen;	866	offs += txtlen;
		867	dns->snddq.remove (txtlen);
480		868
481	//if (sndlen + txtlen > dns_snddq.	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: ;
		898	}
		899	else
		900	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
482	}	901	}
		902	else if (qtype == RR_TYPE_A
		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);
483		908
484	int rdlen = offs - rdlen_offs;	909	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
485		910
486	(*rep) [rdlen_offs - 2] = rdlen >> 8;	911	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
487	(*rep) [rdlen_offs - 1] = rdlen;	912	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
488	#endif	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	}
489	}	936	}
490	}
491		937
492	pkt->len = offs;	938	pkt.len = offs;
493	return pkt;	939	}
494	}	940	}
495		941
496	void	942	void
497	vpn::dnsv4_client (dns_packet *pkt)	943	vpn::dnsv4_client (dns_packet &pkt)
498	{	944	{
499	u16 flags = ntohs (pkt->flags);	945	u16 flags = ntohs (pkt.flags);
500	int offs = 6 * 2; // skip header	946	int offs = 6 * 2; // skip header
501		947
502	pkt->qdcount = ntohs (pkt->qdcount);	948	pkt.qdcount = ntohs (pkt.qdcount);
503	pkt->ancount = ntohs (pkt->ancount);	949	pkt.ancount = ntohs (pkt.ancount);
504		950
		951	// go through our request list and find the corresponding request
505	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	952	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
506	i != dns_sndpq.end ();	953	i != dns_sndpq.end ();
507	++i)	954	++i)
508	if ((*i)->pkt->id == pkt->id)	955	if ((*i)->pkt->id == pkt.id)
509	{	956	{
		957	dns_connection dns = (i)->dns;
510	connection c = (i)->conn;	958	connection *c = dns->c;
511	printf ("GOT RESPONSE id %x %p\n", pkt->id, c);//D	959	int seqno = (*i)->seqno;
		960	u8 data[MAXSIZE], *datap = data;
		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
512	delete *i;	984	delete *i;
513	dns_sndpq.erase (i);	985	dns_sndpq.erase (i);
514		986
515	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	987	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
516	{	988	{
517	char qname[MAXSIZE];	989	char qname[MAXSIZE];
518		990
519	while (pkt->qdcount-- && offs < MAXSIZE - 4)	991	while (pkt.qdcount-- && offs < MAXSIZE - 4)
520	{	992	{
521	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	993	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
522	offs += 4; // skip qtype, qclass	994	offs += 4; // skip qtype, qclass
523	}	995	}
524		996
525	while (pkt->ancount-- && offs < MAXSIZE - 10)	997	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
526	{	998	{
527	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	999	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
528		1000
529	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1001	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
530	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1002	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
531	u32 ttl = (*pkt) [offs++] << 24;	1003	u32 ttl = pkt [offs++] << 24;
532	ttl \|= (*pkt) [offs++] << 16;	1004	ttl \|= pkt [offs++] << 16;
533	ttl \|= (*pkt) [offs++] << 8;	1005	ttl \|= pkt [offs++] << 8;
534	ttl \|= (*pkt) [offs++];	1006	ttl \|= pkt [offs++];
535
536	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1007	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
537		1008
538	printf ("REPLY %d:%d TTL %d RD %d\n", qtype, qclass, ttl, rdlen);	1009	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
539
540	offs += rdlen;
541
542	if (MAXSIZE - offs < rdlen)
543	{	1010	{
		1011	if (rdlen <= MAXSIZE - offs)
		1012	{
544	// decode bytes, finally	1013	// decode bytes, finally
		1014
		1015	while (rdlen)
		1016	{
		1017	int txtlen = pkt [offs++];
		1018
		1019	assert (txtlen + offs < MAXSIZE - 1);
		1020
		1021	memcpy (datap, pkt.at (offs), txtlen);
		1022	datap += txtlen; offs += txtlen;
		1023
		1024	rdlen -= txtlen + 1;
		1025	}
		1026	}
		1027	}
		1028	else if (qtype == RR_TYPE_A)
		1029	{
		1030	u8 ip [4];
		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;
545	}	1083	}
546	}	1084	}
547	}	1085	}
548		1086
		1087	// todo: pkt now used
		1088	if (datap)
		1089	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
		1090
549	break;	1091	break;
550	}	1092	}
551	}	1093	}
552		1094
553	void	1095	void
…		…
557	{	1099	{
558	dns_packet *pkt = new dns_packet;	1100	dns_packet *pkt = new dns_packet;
559	struct sockaddr_in sa;	1101	struct sockaddr_in sa;
560	socklen_t sa_len = sizeof (sa);	1102	socklen_t sa_len = sizeof (sa);
561		1103
562	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);
563		1105
564	if (pkt->len > 0)	1106	if (pkt->len > 0)
		1107	{
565	if (THISNODE->dns_port)	1108	if (THISNODE->dns_port)
566	{	1109	{
567	pkt = dnsv4_server (pkt);	1110	dnsv4_server (*pkt);
568	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);
569	}	1112	}
570	else	1113	else
571	dnsv4_client (pkt);	1114	dnsv4_client (*pkt);
		1115
		1116	delete pkt;
		1117	}
572	}	1118	}
573	}	1119	}
574		1120
575	bool	1121	bool
576	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)
577	{	1123	{
578	// never initialized	1124	if (!dns)
579	if (!dns_snddq && !dns_rcvdq)	1125	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		1126
589	if (!dns_snddq->put (pkt))	1127	if (!dns->snddq.put (pkt))
590	return false;	1128	return false;
591		1129
592	// start timer if neccessary	1130	dns->tw.trigger ();
593	if (!dnsv4_tw.active)
594	dnsv4_cb (dnsv4_tw);
595		1131
596	return true;	1132	return true;
597	}	1133	}
598		1134
599	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
600	connection::dnsv4_cb (time_watcher &w)	1144	dns_connection::time_cb (time_watcher &w)
601	{	1145	{
		1146	// servers have to be polled
		1147	if (THISNODE->dns_port)
		1148	return;
		1149
602	// check for timeouts and (re)transmit	1150	// check for timeouts and (re)transmit
603	tstamp next = NOW + 60;	1151	tstamp next = NOW + poll_interval;
604	dns_req *send = 0;	1152	dns_snd *send = 0;
605		1153
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 ();	1154	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
609	i != vpn->dns_sndpq.end ();	1155	i != vpn->dns_sndpq.end ();
610	++i)	1156	++i)
611	{	1157	{
612	dns_req r = i;	1158	dns_snd r = i;
613		1159
614	if (r->next <= NOW)	1160	if (r->timeout <= NOW)
615	{	1161	{
616	if (!send)	1162	if (!send)
617	{	1163	{
618	send = r;	1164	send = r;
619		1165
620	slog (L_NOISE, _("dnsv4, send req %d\n"), r->pkt->id);
621	r->retry++;	1166	r->retry++;
622	r->next = NOW + r->retry;	1167	r->timeout = NOW + r->retry;
623	}	1168	}
624	}	1169	}
		1170	else
		1171	NEXT (r->timeout);
		1172	}
625		1173
626	if (r->next < next)	1174	if (last_sent + send_interval <= NOW)
627	next = r->next;
628	}	1175	{
629
630	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	}
631	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)	1190	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING)
632	send = new dns_req (this, dns_sndseq++, dns_snddq);	1191	{
		1192	send = new dns_snd (this);
		1193	send->gen_stream_req (sndseq, snddq);
633		1194
634	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);	1195	sndseq = (sndseq + 1) & SEQNO_MASK;
		1196	}
635		1197
		1198	if (send)
		1199	vpn->dns_sndpq.push_back (send);
		1200	}
		1201
636	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	}
637	{	1209	}
638	dns_packet *pkt = send->pkt;	1210	else
		1211	NEXT (last_sent + send_interval);
639		1212
640	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 ());
641		1216
642	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
643	}	1218	if (next < NOW + 0.0001)
644	else if (next < min_next)	1219	next = NOW + 0.1;
645	next = min_next;
646		1220
647	w.start (next);	1221	w.start (next);
648	}	1222	}
649		1223
650	#endif	1224	#endif

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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 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.4 by pcg, Wed Mar 2 05:49:31 2005 UTC vs.
Revision 1.15 by pcg, Fri Mar 4 10:15:45 2005 UTC