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

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.3 by pcg, Tue Mar 1 06:27:20 2005 UTC vs.
Revision 1.18 by pcg, Sat Mar 5 19:13:16 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 0.1 // retry timeouts
		53	#define INITIAL_SYN_TIMEOUT 10. // 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 10 // max. outstanding requests	58	#define MAX_OUTSTANDING 10 // max. outstanding requests
		59	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
		60	#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
48		61
49	/*	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
50		65
51	protocol, in shorthand :)	66	#define SEQNO_MASK 0x3fff
52		67	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
53	client -> server <req> ANY?
54	server -> client <req> TXT <rep>
55
56	<req> is dns64-encoded <client-id:12><recv-seqno:10>[<send-seqno:10><data>]
57	<rep> is dns64-encoded <0:12><recv-seqno:10>[<send-seqno:10><data>]
58
59	if <client-id> is zero, the connection will be configured:
60
61	<0:12><0:4>client-id:12><default-ttl:8><max-size:16><flags:16>
62
63	*/
64		68
65	#define MAX_LBL_SIZE 63	69	#define MAX_LBL_SIZE 63
66	#define MAX_PKT_SIZE 512	70	#define MAX_PKT_SIZE 512
67		71
		72	#define RR_TYPE_A 1
		73	#define RR_TYPE_NULL 10
68	#define RR_TYPE_TXT 16	74	#define RR_TYPE_TXT 16
69	#define RR_TYPE_ANY 255	75	#define RR_TYPE_ANY 255
		76
70	#define RR_CLASS_IN 1	77	#define RR_CLASS_IN 1
71		78
72	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)	79	#define CMD_IP_1 207
73	struct dns64	80	#define CMD_IP_2 46
74	{	81	#define CMD_IP_3 236
75	static const char encode_chars[64 + 1];	82	#define CMD_IP_RST 29
76	static s8 decode_chars[256];	83	#define CMD_IP_SYN 113
		84	#define CMD_IP_REJ 32
77		85
78	static int encode_len (int bytes) { return (bytes * 8 + 5) / 6; }	86	// works for cmaps up to 255 (not 256!)
79	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
80	static void encode (char dst, u8 src, int len);	129	unsigned int encode (char dst, u8 src, unsigned int len);
81	static void decode (u8 dst, char src, int len);	130	unsigned int decode (u8 dst, char src, unsigned int len);
82		131
83	dns64 ();	132	basecoder (const char *cmap);
84	} dns64;	133	};
85		134
86	const char dns64::encode_chars[64 + 1] = "0123456789-abcdefghijklmnopqrstuvwxyz_ABCDEFGHIJKLMNOPQRSTUVWXYZ";	135	basecoder::basecoder (const char *cmap)
87	s8 dns64::decode_chars[256];	136	: cmap (cmap)
88
89	dns64::dns64 ()
90	{	137	{
91	for (int i = 0; i < 64; i++)	138	for (unsigned int len = 0; len < MAX_DEC_LEN; ++len)
92	decode_chars [encode_chars [i]] = i + 1;	139	{
93	}	140	u8 src [MAX_DEC_LEN];
		141	u8 dst [MAX_ENC_LEN];
94		142
95	void 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)
96	{	160	{
97	// slow, but easy to debug	161	return enc_len [len];
98	unsigned int accum, bits = 0;	162	}
		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;
99		208
100	while (len--)	209	while (len--)
101	{	210	{
102	accum <<= 8;	211	u8 val = cmap.decode [(u8)*src++];
103	accum \|= *src++;
104	bits += 8;
105		212
106	while (bits >= 6)	213	if (val != charmap::INVALID)
107	{	214	src_ [elen++] = val;
108	*dst++ = encode_chars [(accum >> (bits - 6)) & 63];	215	}
109	bits -= 6;	216
110	}	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)
111	}	228	{
		229	memset (dst, 0, dlen - n);
		230	memcpy (dst + dlen - n, dst_, n);
		231	}
		232	else
		233	memcpy (dst, dst_ + n - dlen, dlen);
112		234
113	if (bits)	235	return dlen;
114	*dst++ = encode_chars [(accum << (6 - bits)) & 63];
115	}	236	}
116		237
117	void dns64::decode (u8 dst, char src, int len)	238	#if 0
118	{	239	struct test { test (); } test;
119	// slow, but easy to debug
120	unsigned int accum, bits = 0;
121		240
122	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++)
123	{	250	{
124	s8 chr = decode_chars [(u8)*src++];	251	int elen = cdc.encode (enc, in, i);
		252	int dlen = cdc.decode (dec, enc, elen);
125		253
		254	printf ("%d>%d>%d (%s>%s)\n", i, elen, dlen, enc, dec);
		255	}
		256	abort ();
		257	}
		258	#endif
126		259
127	if (!chr)	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, int retry = 0)
		271	{
		272	seqno &= SEQNO_MASK;
		273
		274	u8 hdr[3] = {
		275	clientid,
		276	(seqno >> 8) \| (retry << 6),
		277	seqno,
		278	};
		279
		280	assert (clientid < 256);
		281
		282	cdc26.encode (data, hdr, 3);
		283	}
		284
		285	inline void decode_header (char *data, int &clientid, int &seqno)
		286	{
		287	u8 hdr[3];
		288
		289	cdc26.decode (hdr, data, HDRSIZE);
		290
		291	clientid = hdr[0];
		292	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
		293	}
		294
		295	/////////////////////////////////////////////////////////////////////////////
		296
		297	struct byte_stream
		298	{
		299	u8 *data;
		300	int maxsize;
		301	int fill;
		302
		303	byte_stream (int maxsize);
		304	~byte_stream ();
		305
		306	bool empty () { return !fill; }
		307	int size () { return fill; }
		308
		309	bool put (u8 *data, unsigned int datalen);
		310	bool put (vpn_packet *pkt);
		311	vpn_packet *get ();
		312
		313	u8 *begin () { return data; }
		314	void remove (int count);
		315	};
		316
		317	byte_stream::byte_stream (int maxsize)
		318	: maxsize (maxsize), fill (0)
		319	{
		320	data = new u8 [maxsize];
		321	}
		322
		323	byte_stream::~byte_stream ()
		324	{
		325	delete data;
		326	}
		327
		328	void byte_stream::remove (int count)
		329	{
		330	if (count > fill)
		331	assert (count <= fill);
		332
		333	memmove (data, data + count, fill -= count);
		334	}
		335
		336	bool byte_stream::put (u8 *data, unsigned int datalen)
		337	{
		338	if (maxsize - fill < datalen)
		339	return false;
		340
		341	memcpy (this->data + fill, data, datalen); fill += datalen;
		342
		343	return true;
		344	}
		345
		346	bool byte_stream::put (vpn_packet *pkt)
		347	{
		348	if (maxsize - fill < pkt->len + 2)
		349	return false;
		350
		351	data [fill++] = pkt->len >> 8;
		352	data [fill++] = pkt->len;
		353
		354	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
		355
		356	return true;
		357	}
		358
		359	vpn_packet *byte_stream::get ()
		360	{
		361	unsigned int len;
		362
		363	for (;;)
		364	{
		365	len = (data [0] << 8) \| data [1];
		366
		367	if (len <= MAXSIZE \|\| fill < 2)
128	break;	368	break;
129		369
130	accum <<= 6;	370	// TODO: handle this better than skipping, e.g. by reset
131	accum \|= chr - 1;	371	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
132	bits += 6;	372	remove (1);
133		373	}
134	while (bits >= 8)
135	{	374
136	*dst++ = accum >> (bits - 8);	375	if (fill < len + 2)
137	bits -= 8;	376	return 0;
138	}	377
139	}	378	vpn_packet *pkt = new vpn_packet;
		379
		380	pkt->len = len;
		381	memcpy (pkt->at (0), data + 2, len);
		382	remove (len + 2);
		383
		384	return pkt;
140	}	385	}
141		386
142	/////////////////////////////////////////////////////////////////////////////	387	/////////////////////////////////////////////////////////////////////////////
143		388
144	#define FLAG_QUERY ( 0 << 15)	389	#define FLAG_QUERY ( 0 << 15)
145	#define FLAG_RESPONSE ( 1 << 15)	390	#define FLAG_RESPONSE ( 1 << 15)
146	#define FLAG_OP_MASK (15 << 14)	391	#define FLAG_OP_MASK (15 << 11)
147	#define FLAG_OP_QUERY ( 0 << 11)	392	#define FLAG_OP_QUERY ( 0 << 11)
148	#define FLAG_AA ( 1 << 10)	393	#define FLAG_AA ( 1 << 10)
149	#define FLAG_TC ( 1 << 9)	394	#define FLAG_TC ( 1 << 9)
150	#define FLAG_RD ( 1 << 8)	395	#define FLAG_RD ( 1 << 8)
151	#define FLAG_RA ( 1 << 7)	396	#define FLAG_RA ( 1 << 7)
		397	#define FLAG_AUTH ( 1 << 5)
152	#define FLAG_RCODE_MASK (15 << 0)	398	#define FLAG_RCODE_MASK (15 << 0)
153	#define FLAG_RCODE_OK ( 0 << 0)	399	#define FLAG_RCODE_OK ( 0 << 0)
154	#define FLAG_RCODE_FORMERR ( 1 << 0)	400	#define FLAG_RCODE_FORMERR ( 1 << 0)
155	#define FLAG_RCODE_SERVFAIL ( 2 << 0)	401	#define FLAG_RCODE_SERVFAIL ( 2 << 0)
156	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)	402	#define FLAG_RCODE_NXDOMAIN ( 3 << 0)
157	#define FLAG_RCODE_REFUSED ( 5 << 0)	403	#define FLAG_RCODE_REFUSED ( 5 << 0)
158		404
159	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	405	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
160	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD)	406	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
		407
		408	struct dns_cfg
		409	{
		410	static int next_uid;
		411
		412	u8 id1, id2, id3, id4;
		413	u8 version;
		414	u8 rrtype;
		415	u8 flags;
		416	u8 def_ttl;
		417	u8 rcv_cdc;
		418	u8 snd_cdc;
		419	u16 max_size;
		420	u16 client;
		421	u16 uid; // to make request unique
		422
		423	u8 reserved[8];
		424
		425	void reset (int clientid);
		426	bool valid ();
		427	};
		428
		429	int dns_cfg::next_uid;
		430
		431	void dns_cfg::reset (int clientid)
		432	{
		433	id1 = 'G';
		434	id2 = 'V';
		435	id3 = 'P';
		436	id4 = 'E';
		437
		438	version = 1;
		439
		440	rrtype = RR_TYPE_TXT;
		441	flags = 0;
		442	def_ttl = 1;
		443	rcv_cdc = 0;
		444	snd_cdc = 62;
		445	max_size = ntohs (MAX_PKT_SIZE);
		446	client = ntohs (clientid);
		447	uid = next_uid++;
		448
		449	memset (reserved, 0, 8);
		450	}
		451
		452	bool dns_cfg::valid ()
		453	{
		454	return id1 == 'G'
		455	&& id2 == 'V'
		456	&& id3 == 'P'
		457	&& id4 == 'E'
		458	&& version == 1
		459	&& flags == 0
		460	&& rcv_cdc == 0
		461	&& snd_cdc == 62
		462	&& max_size == ntohs (MAX_PKT_SIZE);
		463	}
161		464
162	struct dns_packet : net_packet	465	struct dns_packet : net_packet
163	{	466	{
164	u16 id;	467	u16 id;
165	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	468	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
…		…
204	return data - orig;	507	return data - orig;
205	}	508	}
206		509
207	/////////////////////////////////////////////////////////////////////////////	510	/////////////////////////////////////////////////////////////////////////////
208		511
		512	static u16 dns_id = 0; // TODO: should be per-vpn
		513
		514	static u16 next_id ()
		515	{
		516	if (!dns_id)
		517	dns_id = time (0);
		518
		519	// the simplest lsfr with periodicity 65535 i could find
		520	dns_id = (dns_id << 1)
		521	\| (((dns_id >> 1)
		522	^ (dns_id >> 2)
		523	^ (dns_id >> 4)
		524	^ (dns_id >> 15)) & 1);
		525
		526	return dns_id;
		527	}
		528
209	struct dns_req	529	struct dns_rcv;
		530	struct dns_snd;
		531
		532	struct dns_connection
		533	{
		534	connection *c;
		535	struct vpn *vpn;
		536
		537	dns_cfg cfg;
		538
		539	bool established;
		540
		541	tstamp last_received;
		542	tstamp last_sent;
		543	double last_latency;
		544	double poll_interval, send_interval;
		545
		546	vector<dns_rcv *> rcvpq;
		547
		548	byte_stream rcvdq; int rcvseq;
		549	byte_stream snddq; int sndseq;
		550
		551	void time_cb (time_watcher &w); time_watcher tw;
		552	void receive_rep (dns_rcv *r);
		553
		554	dns_connection (connection *c);
		555	~dns_connection ();
		556	};
		557
		558	struct dns_snd
210	{	559	{
211	dns_packet *pkt;	560	dns_packet *pkt;
212	tstamp next;	561	tstamp timeout, sent;
213	int retry;	562	int retry;
		563	struct dns_connection *dns;
		564	int seqno;
		565	bool stdhdr;
214		566
215	dns_req (connection c, vpn_packet p, int &offs);	567	void gen_stream_req (int seqno, byte_stream &stream);
		568	void gen_syn_req ();
		569
		570	dns_snd (dns_connection *dns);
		571	~dns_snd ();
216	};	572	};
217		573
		574	dns_snd::dns_snd (dns_connection *dns)
		575	: dns (dns)
		576	{
		577	timeout = 0;
		578	retry = 0;
		579	seqno = 0;
		580	sent = NOW;
		581	stdhdr = false;
		582
		583	pkt = new dns_packet;
		584
		585	pkt->id = next_id ();
		586	}
		587
		588	dns_snd::~dns_snd ()
		589	{
		590	delete pkt;
		591	}
		592
		593	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		594	{
		595	// add tunnel domain
		596	for (;;)
		597	{
		598	const char *end = strchr (domain, '.');
		599
		600	if (!end)
		601	end = domain + strlen (domain);
		602
		603	int len = end - domain;
		604
		605	pkt [offs++] = len;
		606	memcpy (pkt.at (offs), domain, len);
		607	offs += len;
		608
		609	if (!*end)
		610	break;
		611
		612	domain = end + 1;
		613	}
		614	}
		615
		616	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
		617	{
		618	stdhdr = true;
		619	this->seqno = seqno;
		620
		621	timeout = NOW + INITIAL_TIMEOUT;
		622
		623	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		624	pkt->qdcount = htons (1);
		625
		626	int offs = 6*2;
		627	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);
		628	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
		629	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
		630
		631	char enc[256], *encp = enc;
		632	encode_header (enc, THISNODE->id, seqno);
		633
		634	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
		635
		636	if (datalen > stream.size ())
		637	datalen = stream.size ();
		638
		639	int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
		640	stream.remove (datalen);
		641
		642	while (enclen)
		643	{
		644	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
		645
		646	(*pkt)[offs++] = lbllen;
		647	memcpy (pkt->at (offs), encp, lbllen);
		648
		649	offs += lbllen;
		650	encp += lbllen;
		651
		652	enclen -= lbllen;
		653	}
		654
		655	append_domain (*pkt, offs, THISNODE->domain);
		656
		657	(*pkt)[offs++] = 0;
		658	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		659	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		660
		661	pkt->len = offs;
		662	}
		663
		664	void dns_snd::gen_syn_req ()
		665	{
		666	timeout = NOW + INITIAL_SYN_TIMEOUT;
		667
		668	printf ("send syn\n");//D
		669
		670	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		671	pkt->qdcount = htons (1);
		672
		673	int offs = 6 * 2;
		674
		675	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
		676
		677	assert (elen <= MAX_LBL_SIZE);
		678
		679	(*pkt)[offs] = elen;
		680	offs += elen + 1;
		681	append_domain (*pkt, offs, THISNODE->domain);
		682
		683	(*pkt)[offs++] = 0;
		684	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
		685	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		686
		687	pkt->len = offs;
		688	}
		689
218	struct dns_rep	690	struct dns_rcv
219	{	691	{
		692	int seqno;
		693	dns_packet *pkt; // reply packet
		694	u8 data [MAXSIZE]; // actually part of the reply packet...
		695	int datalen;
		696
		697	dns_rcv (int seqno, u8 *data, int datalen);
		698	~dns_rcv ();
220	};	699	};
221		700
222	static u16 dns_id; // TODO: should be per-vpn	701	dns_rcv::dns_rcv (int seqno, u8 *data, int datalen)
223		702	: seqno (seqno), pkt (new dns_packet), datalen (datalen)
224	dns_req::dns_req (connection c, vpn_packet p, int &offs)
225	{	703	{
226	next = 0;	704	memcpy (this->data, data, datalen);
227	retry = 0;	705	}
228		706
229	pkt = new dns_packet;	707	dns_rcv::~dns_rcv ()
230		708	{
231	pkt->id = dns_id++;	709	delete pkt;
232	pkt->flags = DEFAULT_CLIENT_FLAGS;
233	pkt->qdcount = htons (1 * 0);
234	pkt->ancount = 0;
235	pkt->nscount = 0;
236	pkt->arcount = 0;
237
238	offs += 10000;
239
240	c->dns_sndq.push_back (this);
241	}	710	}
242		711
243	/////////////////////////////////////////////////////////////////////////////	712	/////////////////////////////////////////////////////////////////////////////
244		713
245	struct dns_cfg	714	dns_connection::dns_connection (connection *c)
		715	: c (c)
		716	, rcvdq (MAX_BACKLOG * 2)
		717	, snddq (MAX_BACKLOG * 2)
		718	, tw (this, &dns_connection::time_cb)
246	{	719	{
247	u8 id1, id2, id3;	720	vpn = c->vpn;
248	u8 def_ttl;
249	u8 unused1;
250	u16 max_size;
251	u8 flags1, flags2;
252	};
253		721
254	// reply to client-poll	722	established = false;
255	void dnsv4_poll (dns_packet *pkt, int &offs)
256	{
257	int dlen = MAX_PKT_SIZE - offs - 2;
258		723
259	(*pkt) [offs++] = 0;	724	rcvseq = sndseq = 0;
260	(*pkt) [offs++] = 5;
261	memcpy (&((*pkt)[offs]), "\01H\02\xff\x00", 5);
262	offs += 5;
263		725
264	pkt->ancount = htons (1);	726	last_sent = last_received = 0;
		727	poll_interval = MIN_POLL_INTERVAL;
		728	send_interval = 0.5; // starting rate
		729	last_latency = INITIAL_TIMEOUT;
		730	}
		731
		732	dns_connection::~dns_connection ()
		733	{
		734	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		735	i != rcvpq.end ();
		736	++i)
		737	delete *i;
		738	}
		739
		740	void dns_connection::receive_rep (dns_rcv *r)
		741	{
		742	if (r->datalen)
		743	{
		744	last_received = NOW;
		745	tw.trigger ();
		746
		747	poll_interval = send_interval;
		748	}
		749	else
		750	{
		751	poll_interval *= 1.5;
		752	if (poll_interval > MAX_POLL_INTERVAL)
		753	poll_interval = MAX_POLL_INTERVAL;
		754	}
		755
		756	rcvpq.push_back (r);
		757
		758	redo:
		759
		760	// find next packet
		761	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
		762	if (SEQNO_EQ (rcvseq, (*i)->seqno))
		763	{
		764	// enter the packet into our input stream
		765	r = *i;
		766
		767	// remove the oldest packet, look forward, as it's oldest first
		768	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
		769	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
		770	{
		771	delete *j;
		772	rcvpq.erase (j);
		773	break;
		774	}
		775
		776	rcvseq = (rcvseq + 1) & SEQNO_MASK;
		777
		778	if (!rcvdq.put (r->data, r->datalen))
		779	{
		780	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
		781	abort (); // MUST never overflow, can be caused by data corruption, TODO
		782	}
		783
		784	while (vpn_packet *pkt = rcvdq.get ())
		785	{
		786	sockinfo si;
		787	si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4;
		788
		789	vpn->recv_vpn_packet (pkt, si);
		790
		791	delete pkt;
		792	}
		793
		794	// check for further packets
		795	goto redo;
		796	}
		797	}
		798
		799	void
		800	vpn::dnsv4_server (dns_packet &pkt)
		801	{
		802	u16 flags = ntohs (pkt.flags);
		803
		804	int offs = 6 * 2; // skip header
		805
265	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	806	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
266		807
267	printf ("we have room for %d bytes\n", dlen);	808	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
		809	&& pkt.qdcount == htons (1))
		810	{
		811	char qname[MAXSIZE];
		812	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
		813
		814	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
		815	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
		816
		817	pkt.qdcount = htons (1);
		818	pkt.ancount = 0;
		819	pkt.nscount = 0; // should be self, as other nameservers reply like this
		820	pkt.arcount = 0; // a record for self, as other nameservers reply like this
		821
		822	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
		823
		824	int dlen = strlen (THISNODE->domain);
		825
		826	if (qclass == RR_CLASS_IN
		827	&& qlen > dlen + 1
		828	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))
		829	{
		830	// now generate reply
		831	pkt.ancount = htons (1); // one answer RR
		832	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
		833
		834	if ((qtype == RR_TYPE_ANY
		835	\|\| qtype == RR_TYPE_TXT
		836	\|\| qtype == RR_TYPE_NULL)
		837	&& qlen > dlen + 1 + HDRSIZE)
		838	{
		839	// correct class, domain: parse
		840	int client, seqno;
		841	decode_header (qname, client, seqno);
		842
		843	u8 data[MAXSIZE];
		844	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
		845
		846	if (0 < client && client <= conns.size ())
		847	{
		848	connection *c = conns [client - 1];
		849	dns_connection *dns = c->dns;
		850	dns_rcv *rcv;
		851	bool in_seq;
		852
		853	if (dns)
		854	{
		855	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
		856	if (SEQNO_EQ ((*i)->seqno, seqno))
		857	{
		858	// already seen that request: simply reply with the cached reply
		859	dns_rcv r = i;
		860
		861	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		862
		863	// refresh header & id, as the retry count could have changed
		864	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		865	r->pkt->id = pkt.id;
		866
		867	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		868
		869	goto duplicate_request;
		870	}
		871
		872	in_seq = dns->rcvseq == seqno;
		873
		874	// new packet, queue
		875	rcv = new dns_rcv (seqno, data, datalen);
		876	dns->receive_rep (rcv);
		877	}
		878
		879	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		880
		881	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		882	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		883	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		884	pkt [offs++] = 0; pkt [offs++] = 0;
		885	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
		886
		887	int rdlen_offs = offs += 2;
		888
		889	int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
		890	// bind doesn't compress well, so reduce further by one label length
		891	dlen -= qlen;
		892
		893	if (dns)
		894	{
		895	// only put data into in-order sequence packets, if
		896	// we receive out-of-order packets we generate empty
		897	// replies
		898	while (dlen > 1 && !dns->snddq.empty () && in_seq)
		899	{
		900	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		901
		902	if (txtlen > dns->snddq.size ())
		903	txtlen = dns->snddq.size ();
		904
		905	pkt[offs++] = txtlen;
		906	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
		907	offs += txtlen;
		908	dns->snddq.remove (txtlen);
		909
		910	dlen -= txtlen + 1;
		911	}
		912
		913	// avoid empty TXT rdata
		914	if (offs == rdlen_offs)
		915	pkt[offs++] = 0;
		916
		917	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
		918	}
		919	else
		920	{
		921	// send RST
		922	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		923	pkt [offs++] = CMD_IP_RST;
		924	}
		925
		926	int rdlen = offs - rdlen_offs;
		927
		928	pkt [rdlen_offs - 2] = rdlen >> 8;
		929	pkt [rdlen_offs - 1] = rdlen;
		930
		931	if (dns)
		932	{
		933	// now update dns_rcv copy
		934	rcv->pkt->len = offs;
		935	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		936	}
		937
		938	duplicate_request: ;
		939	}
		940	else
		941	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		942	}
		943	else if (qtype == RR_TYPE_A
		944	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		945	{
		946	dns_cfg cfg;
		947	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		948	int client = ntohs (cfg.client);
		949
		950	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
		951
		952	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
		953	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		954	pkt [offs++] = 0; pkt [offs++] = 0;
		955	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		956	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
		957
		958	slog (L_INFO, _("DNS: client %d tries to connect"), client);
		959
		960	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		961	pkt [offs++] = CMD_IP_REJ;
		962
		963	if (0 < client && client <= conns.size ())
		964	{
		965	connection *c = conns [client - 1];
		966
		967	if (cfg.valid ())
		968	{
		969	pkt [offs - 1] = CMD_IP_SYN;
		970
		971	delete c->dns;
		972	c->dns = new dns_connection (c);
		973	c->dns->cfg = cfg;
		974	}
		975	}
		976	}
		977	}
		978
		979	pkt.len = offs;
		980	}
		981	}
		982
		983	void
		984	vpn::dnsv4_client (dns_packet &pkt)
		985	{
		986	u16 flags = ntohs (pkt.flags);
		987	int offs = 6 * 2; // skip header
		988
		989	pkt.qdcount = ntohs (pkt.qdcount);
		990	pkt.ancount = ntohs (pkt.ancount);
		991
		992	// go through our request list and find the corresponding request
		993	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
		994	i != dns_sndpq.end ();
		995	++i)
		996	if ((*i)->pkt->id == pkt.id)
		997	{
		998	dns_connection dns = (i)->dns;
		999	connection *c = dns->c;
		1000	int seqno = (*i)->seqno;
		1001	u8 data[MAXSIZE], *datap = data;
		1002
		1003	if ((*i)->retry)
		1004	{
		1005	dns->send_interval *= 1.01;
		1006	if (dns->send_interval > MAX_SEND_INTERVAL)
		1007	dns->send_interval = MAX_SEND_INTERVAL;
		1008	}
		1009	else
		1010	{
		1011	#if 1
		1012	dns->send_interval *= 0.999;
		1013	#endif
		1014	if (dns->send_interval < MIN_SEND_INTERVAL)
		1015	dns->send_interval = MIN_SEND_INTERVAL;
		1016
		1017	// the latency surely puts an upper bound on
		1018	// the minimum send interval
		1019	double latency = NOW - (*i)->sent;
		1020	dns->last_latency = latency;
		1021
		1022	if (dns->send_interval > latency)
		1023	dns->send_interval = latency;
		1024	}
		1025
		1026	delete *i;
		1027	dns_sndpq.erase (i);
		1028
		1029	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
		1030	{
		1031	char qname[MAXSIZE];
		1032
		1033	while (pkt.qdcount-- && offs < MAXSIZE - 4)
		1034	{
		1035	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
		1036	offs += 4; // skip qtype, qclass
		1037	}
		1038
		1039	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
		1040	{
		1041	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
		1042
		1043	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
		1044	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
		1045	u32 ttl = pkt [offs++] << 24;
		1046	ttl \|= pkt [offs++] << 16;
		1047	ttl \|= pkt [offs++] << 8;
		1048	ttl \|= pkt [offs++];
		1049	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
		1050
		1051	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
		1052	{
		1053	if (rdlen <= MAXSIZE - offs)
		1054	{
		1055	// decode bytes, finally
		1056
		1057	while (rdlen)
		1058	{
		1059	int txtlen = pkt [offs++];
		1060
		1061	assert (txtlen + offs < MAXSIZE - 1);
		1062
		1063	memcpy (datap, pkt.at (offs), txtlen);
		1064	datap += txtlen; offs += txtlen;
		1065
		1066	rdlen -= txtlen + 1;
		1067	}
		1068	}
		1069	}
		1070	else if (qtype == RR_TYPE_A)
		1071	{
		1072	u8 ip [4];
		1073
		1074	ip [0] = pkt [offs++];
		1075	ip [1] = pkt [offs++];
		1076	ip [2] = pkt [offs++];
		1077	ip [3] = pkt [offs++];
		1078
		1079	if (ip [0] == CMD_IP_1
		1080	&& ip [1] == CMD_IP_2
		1081	&& ip [2] == CMD_IP_3)
		1082	{
		1083	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
		1084
		1085	if (ip [3] == CMD_IP_RST)
		1086	{
		1087	slog (L_DEBUG, _("DNS: got tunnel RST request"));
		1088
		1089	delete dns; c->dns = 0;
		1090
		1091	return;
		1092	}
		1093	else if (ip [3] == CMD_IP_SYN)
		1094	{
		1095	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
		1096	dns->established = true;
		1097	}
		1098	else if (ip [3] == CMD_IP_REJ)
		1099	{
		1100	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1101	abort ();
		1102	}
		1103	else
		1104	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
		1105	}
		1106	else
		1107	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
		1108	ip [0], ip [1], ip [2], ip [3]);
		1109
		1110	return;
		1111	}
		1112
		1113	int client, rseqno;
		1114	decode_header (qname, client, rseqno);
		1115
		1116	if (client != THISNODE->id)
		1117	{
		1118	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
		1119	datap = 0;
		1120	}
		1121	else if (rseqno != seqno)
		1122	{
		1123	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
		1124	datap = 0;
		1125	}
		1126	}
		1127	}
		1128
		1129	// todo: pkt now used
		1130	if (datap)
		1131	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
		1132
		1133	break;
		1134	}
268	}	1135	}
269		1136
270	void	1137	void
271	vpn::dnsv4_ev (io_watcher &w, short revents)	1138	vpn::dnsv4_ev (io_watcher &w, short revents)
272	{	1139	{
…		…
274	{	1141	{
275	dns_packet *pkt = new dns_packet;	1142	dns_packet *pkt = new dns_packet;
276	struct sockaddr_in sa;	1143	struct sockaddr_in sa;
277	socklen_t sa_len = sizeof (sa);	1144	socklen_t sa_len = sizeof (sa);
278		1145
279	int len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1146	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
280	pkt->len = len;
281		1147
282	u16 flags = ntohs (pkt->flags);	1148	if (pkt->len > 0)
283
284	if (THISNODE->dns_port)
285	{	1149	{
286	// server	1150	if (THISNODE->dns_port)
287	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
288
289	int offs = 6 * 2; // skip header
290
291	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))
292	&& pkt->qdcount == htons (1))
293	{	1151	{
294	char qname[MAXSIZE];	1152	dnsv4_server (*pkt);
295	int qlen = pkt->decode_label ((char *)qname, MAXSIZE, offs);	1153	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
		1154	}
		1155	else
		1156	dnsv4_client (*pkt);
296		1157
297	printf ("rcvd packet len %d, id%04x flags%04x q%04x a%04x n%04x a%04x <%s>\n", len,	1158	delete pkt;
298	pkt->id, flags, pkt->qdcount, pkt->ancount, pkt->nscount, pkt->arcount, qname);//D	1159	}
		1160	}
		1161	}
299		1162
300	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1163	bool
301	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1164	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
		1165	{
		1166	int client = ntohs (si.port);
302		1167
303	pkt->qdcount = htons (1);	1168	assert (0 < client && client <= conns.size ());
304	pkt->ancount = 0;
305	pkt->nscount = 0; // should be self, as other nameservers reply like this
306	pkt->arcount = 0; // a record for self, as other nameservers reply like this
307		1169
308	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	1170	connection *c = conns [client - 1];
309		1171
310	int dlen = strlen (THISNODE->domain);	1172	if (!c->dns)
		1173	c->dns = new dns_connection (c);
		1174
		1175	if (!c->dns->snddq.put (pkt))
		1176	return false;
311		1177
312	if (qclass == RR_CLASS_IN	1178	c->dns->tw.trigger ();
313	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)	1179
314	&& qlen > dlen + 1	1180	return true;
315	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	1181	}
		1182
		1183	void
		1184	connection::dnsv4_reset_connection ()
		1185	{
		1186	//delete dns; dns = 0; //TODO
		1187	}
		1188
		1189	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1190
		1191	void
		1192	dns_connection::time_cb (time_watcher &w)
		1193	{
		1194	// servers have to be polled
		1195	if (THISNODE->dns_port)
		1196	return;
		1197
		1198	// check for timeouts and (re)transmit
		1199	tstamp next = NOW + poll_interval;
		1200	dns_snd *send = 0;
		1201
		1202	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
		1203	i != vpn->dns_sndpq.end ();
		1204	++i)
		1205	{
		1206	dns_snd r = i;
		1207
		1208	if (r->timeout <= NOW)
		1209	{
		1210	if (!send)
		1211	{
		1212	send = r;
		1213
		1214	r->retry++;
		1215	r->timeout = NOW + (r->retry * last_latency * 8.);
		1216
		1217	// the following code changes the query section a bit, forcing
		1218	// the forwarder to generate a new request
		1219	if (r->stdhdr)
316	{	1220	{
317	// correct class, now generate reply	1221	//printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
318	pkt->ancount = htons (1); // one answer RR	1222	//encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
319
320	(*pkt) [offs++] = 0xc0;
321	(pkt) [offs++] = 6 2; // same as in query section
322
323	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;
324	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;
325
326	(pkt) [offs++] = 0; (pkt) [offs++] = 0;
327	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL
328
329	dnsv4_poll (pkt, offs);
330	printf ("correct class\n");
331	}	1223	}
332	}	1224	}
333
334	sendto (w.fd, &((pkt)[0]), offs, 0, (sockaddr )&sa, sa_len);
335	}	1225	}
336	else	1226	else
		1227	NEXT (r->timeout);
		1228	}
		1229
		1230	if (last_sent + send_interval <= NOW)
		1231	{
		1232	if (!send)
337	{	1233	{
338	// client	1234	// generate a new packet, if wise
		1235
		1236	if (!established)
		1237	{
		1238	if (vpn->dns_sndpq.empty ())
		1239	{
		1240	send = new dns_snd (this);
		1241
		1242	printf ("new conn %p %d\n", this, c->conf->id);//D
		1243	cfg.reset (THISNODE->id);
		1244	send->gen_syn_req ();
		1245	}
		1246	}
		1247	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
		1248	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1249	{
		1250	//printf ("sending data request etc.\n"); //D
		1251	if (!snddq.empty ())
		1252	{
		1253	poll_interval = send_interval;
		1254	NEXT (NOW + send_interval);
		1255	}
		1256
		1257	send = new dns_snd (this);
		1258	send->gen_stream_req (sndseq, snddq);
		1259	send->timeout = NOW + last_latency * 8.;
		1260
		1261	sndseq = (sndseq + 1) & SEQNO_MASK;
		1262	}
		1263
		1264	if (send)
		1265	vpn->dns_sndpq.push_back (send);
339	}	1266	}
340	}
341	}
342		1267
343	bool	1268	if (send)
344	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
345	{
346	if (dns_sndq.size () >= MAX_OUTSTANDING)
347	return false;
348
349	// split vpn packet into dns packets, add to sndq
350	for (int offs = 0; offs < pkt->len; )
351	new dns_req (this, pkt, offs);
352
353	// force transmit
354	dnsv4_cb (dnsv4_tw);
355
356	return true;
357	}
358
359	void
360	connection::dnsv4_cb (time_watcher &w)
361	{
362	// check for timeouts and (re)transmit
363	tstamp next = NOW + 60;
364
365	slog (L_NOISE, _("dnsv4, %d packets in send queue\n"), dns_sndq.size ());
366
367	if (dns_sndq.empty ())
368	{
369	next = NOW + 1;
370	// push poll packet
371	}
372
373	for (vector<dns_req *>::iterator i = dns_sndq.begin ();
374	i != dns_sndq.end ();
375	++i)
376	{
377	dns_req r = i;
378
379	if (r->next <= NOW)
380	{	1269	{
381	slog (L_NOISE, _("dnsv4, send req %d\n"), r->pkt->id);	1270	last_sent = NOW;
382	r->retry++;	1271	sendto (vpn->dnsv4_fd,
383	r->next = NOW + r->retry;	1272	send->pkt->at (0), send->pkt->len, 0,
		1273	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
384	}	1274	}
385
386	if (r->next < next)
387	next = r->next;
388	}	1275	}
		1276	else
		1277	NEXT (last_sent + send_interval);
389		1278
390	printf ("%f next\n", next);	1279	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)",
		1280	poll_interval, send_interval, next - NOW,
		1281	vpn->dns_sndpq.size (), snddq.size ());
		1282
		1283	// TODO: no idea when this happens, but when next < NOW, we have a problem
		1284	if (next < NOW + 0.0001)
		1285	next = NOW + 0.1;
		1286
391	w.start (next);	1287	w.start (next);
392	}	1288	}
393		1289
394	#endif	1290	#endif
395		1291

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.3 by pcg, Tue Mar 1 06:27:20 2005 UTC vs. Revision 1.18 by pcg, Sat Mar 5 19:13:16 2005 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.3 by pcg, Tue Mar 1 06:27:20 2005 UTC vs.
Revision 1.18 by pcg, Sat Mar 5 19:13:16 2005 UTC