1 |
pcg |
1.1 |
/* |
2 |
|
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vpn_dns.C -- handle the dns tunnel part of the protocol. |
3 |
root |
1.51 |
Copyright (C) 2003-2011 Marc Lehmann <gvpe@schmorp.de> |
4 |
pcg |
1.1 |
|
5 |
pcg |
1.7 |
This file is part of GVPE. |
6 |
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7 |
pcg |
1.47 |
GVPE is free software; you can redistribute it and/or modify it |
8 |
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under the terms of the GNU General Public License as published by the |
9 |
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Free Software Foundation; either version 3 of the License, or (at your |
10 |
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option) any later version. |
11 |
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This program is distributed in the hope that it will be useful, but |
13 |
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WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General |
15 |
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Public License for more details. |
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You should have received a copy of the GNU General Public License along |
18 |
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with this program; if not, see <http://www.gnu.org/licenses/>. |
19 |
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20 |
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Additional permission under GNU GPL version 3 section 7 |
21 |
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22 |
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If you modify this Program, or any covered work, by linking or |
23 |
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combining it with the OpenSSL project's OpenSSL library (or a modified |
24 |
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version of that library), containing parts covered by the terms of the |
25 |
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OpenSSL or SSLeay licenses, the licensors of this Program grant you |
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additional permission to convey the resulting work. Corresponding |
27 |
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Source for a non-source form of such a combination shall include the |
28 |
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source code for the parts of OpenSSL used as well as that of the |
29 |
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covered work. |
30 |
pcg |
1.1 |
*/ |
31 |
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|
32 |
pcg |
1.38 |
// TODO: EDNS0 option to increase dns mtu? |
33 |
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// TODO: re-write dns packet parsing/creation using a safe mem-buffer |
34 |
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// to ensure no buffer overflows or similar problems. |
35 |
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36 |
pcg |
1.1 |
#include "config.h" |
37 |
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38 |
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#if ENABLE_DNS |
39 |
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40 |
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// dns processing is EXTREMELY ugly. For obvious(?) reasons. |
41 |
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// it's a hack, use only in emergency situations please. |
42 |
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43 |
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#include <cstring> |
44 |
pcg |
1.20 |
#include <cassert> |
45 |
pcg |
1.1 |
|
46 |
|
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#include <sys/types.h> |
47 |
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#include <sys/socket.h> |
48 |
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#include <sys/wait.h> |
49 |
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#include <sys/uio.h> |
50 |
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#include <errno.h> |
51 |
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#include <time.h> |
52 |
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#include <unistd.h> |
53 |
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#include <fcntl.h> |
54 |
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55 |
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#include <map> |
56 |
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57 |
pcg |
1.44 |
#include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */ |
58 |
pcg |
1.8 |
#include <gmp.h> |
59 |
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60 |
pcg |
1.1 |
#include "netcompat.h" |
61 |
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62 |
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#include "vpn.h" |
63 |
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|
64 |
root |
1.52 |
#define MIN_POLL_INTERVAL 0.025 // poll at most this often when no data received |
65 |
root |
1.51 |
#define MAX_POLL_INTERVAL 1. // how often to poll minimally when the server has no data |
66 |
pcg |
1.10 |
|
67 |
pcg |
1.17 |
#define INITIAL_TIMEOUT 0.1 // retry timeouts |
68 |
pcg |
1.36 |
#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn |
69 |
pcg |
1.10 |
|
70 |
root |
1.52 |
#define MAX_SEND_INTERVAL 5. // optimistic? |
71 |
pcg |
1.1 |
|
72 |
pcg |
1.17 |
#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog |
73 |
pcg |
1.35 |
#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE |
74 |
pcg |
1.5 |
|
75 |
pcg |
1.34 |
#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well |
76 |
pcg |
1.5 |
// 240 leaves about 4 bytes of server reply data |
77 |
pcg |
1.33 |
// every request byte less give room for two reply bytes |
78 |
pcg |
1.5 |
|
79 |
pcg |
1.32 |
#define SEQNO_MASK 0x3fff |
80 |
pcg |
1.8 |
#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) |
81 |
pcg |
1.1 |
|
82 |
pcg |
1.8 |
#define MAX_LBL_SIZE 63 |
83 |
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#define MAX_PKT_SIZE 512 |
84 |
pcg |
1.1 |
|
85 |
pcg |
1.10 |
#define RR_TYPE_A 1 |
86 |
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#define RR_TYPE_NULL 10 |
87 |
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#define RR_TYPE_TXT 16 |
88 |
pcg |
1.48 |
#define RR_TYPE_AAAA 28 |
89 |
pcg |
1.8 |
#define RR_TYPE_ANY 255 |
90 |
pcg |
1.10 |
|
91 |
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#define RR_CLASS_IN 1 |
92 |
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93 |
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#define CMD_IP_1 207 |
94 |
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#define CMD_IP_2 46 |
95 |
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#define CMD_IP_3 236 |
96 |
root |
1.51 |
|
97 |
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#define CMD_IP_RST 29 // some error, reset and retry |
98 |
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#define CMD_IP_REJ 32 // do not want you |
99 |
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#define CMD_IP_SYN 113 // connection established |
100 |
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#define CMD_IP_CSE 213 // connection established, but likely case mismatch |
101 |
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102 |
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static bool |
103 |
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is_uc (char c) |
104 |
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{ |
105 |
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return 'A' <= c && c <= 'Z'; |
106 |
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} |
107 |
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108 |
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static bool |
109 |
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is_lc (char c) |
110 |
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{ |
111 |
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return 'a' <= c && c <= 'z'; |
112 |
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} |
113 |
pcg |
1.1 |
|
114 |
pcg |
1.8 |
// works for cmaps up to 255 (not 256!) |
115 |
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struct charmap |
116 |
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{ |
117 |
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enum { INVALID = (u8)255 }; |
118 |
pcg |
1.1 |
|
119 |
pcg |
1.8 |
char encode [256]; // index => char |
120 |
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u8 decode [256]; // char => index |
121 |
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unsigned int size; |
122 |
pcg |
1.2 |
|
123 |
pcg |
1.8 |
charmap (const char *cmap); |
124 |
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}; |
125 |
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126 |
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charmap::charmap (const char *cmap) |
127 |
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{ |
128 |
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char *enc = encode; |
129 |
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u8 *dec = decode; |
130 |
pcg |
1.2 |
|
131 |
pcg |
1.8 |
memset (enc, (char) 0, 256); |
132 |
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memset (dec, (char)INVALID, 256); |
133 |
pcg |
1.1 |
|
134 |
pcg |
1.8 |
for (size = 0; cmap [size]; size++) |
135 |
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{ |
136 |
root |
1.50 |
char c = cmap [size]; |
137 |
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138 |
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enc [size] = c; |
139 |
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dec [(u8)c] = size; |
140 |
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141 |
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// allow lowercase/uppercase aliases if possible |
142 |
root |
1.51 |
if (is_uc (c) && dec [c + ('a' - 'A')] == INVALID) dec [c + ('a' - 'A')] = size; |
143 |
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if (is_lc (c) && dec [c - ('a' - 'A')] == INVALID) dec [c - ('a' - 'A')] = size; |
144 |
pcg |
1.8 |
} |
145 |
pcg |
1.1 |
|
146 |
pcg |
1.8 |
assert (size < 256); |
147 |
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} |
148 |
pcg |
1.2 |
|
149 |
pcg |
1.8 |
#define MAX_DEC_LEN 500 |
150 |
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#define MAX_ENC_LEN (MAX_DEC_LEN * 2) |
151 |
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#define MAX_LIMBS ((MAX_DEC_LEN * 8 + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS) |
152 |
pcg |
1.2 |
|
153 |
pcg |
1.8 |
// ugly. minimum base is 16(!) |
154 |
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struct basecoder |
155 |
pcg |
1.2 |
{ |
156 |
pcg |
1.8 |
charmap cmap; |
157 |
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unsigned int enc_len [MAX_DEC_LEN]; |
158 |
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unsigned int dec_len [MAX_ENC_LEN]; |
159 |
pcg |
1.2 |
|
160 |
root |
1.51 |
unsigned int encode_len (unsigned int len) const; |
161 |
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unsigned int decode_len (unsigned int len) const; |
162 |
pcg |
1.8 |
|
163 |
root |
1.51 |
unsigned int encode (char *dst, u8 *src, unsigned int len) const; |
164 |
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unsigned int decode (u8 *dst, char *src, unsigned int len) const; |
165 |
pcg |
1.8 |
|
166 |
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basecoder (const char *cmap); |
167 |
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}; |
168 |
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169 |
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basecoder::basecoder (const char *cmap) |
170 |
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: cmap (cmap) |
171 |
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{ |
172 |
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for (unsigned int len = 0; len < MAX_DEC_LEN; ++len) |
173 |
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{ |
174 |
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u8 src [MAX_DEC_LEN]; |
175 |
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u8 dst [MAX_ENC_LEN]; |
176 |
pcg |
1.2 |
|
177 |
pcg |
1.8 |
memset (src, 255, len); |
178 |
pcg |
1.2 |
|
179 |
pcg |
1.8 |
mp_limb_t m [MAX_LIMBS]; |
180 |
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mp_size_t n; |
181 |
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182 |
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n = mpn_set_str (m, src, len, 256); |
183 |
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n = mpn_get_str (dst, this->cmap.size, m, n); |
184 |
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185 |
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for (int i = 0; !dst [i]; ++i) |
186 |
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n--; |
187 |
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188 |
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enc_len [len] = n; |
189 |
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dec_len [n] = len; |
190 |
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} |
191 |
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} |
192 |
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193 |
root |
1.49 |
unsigned int |
194 |
root |
1.51 |
basecoder::encode_len (unsigned int len) const |
195 |
pcg |
1.8 |
{ |
196 |
|
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return enc_len [len]; |
197 |
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} |
198 |
pcg |
1.2 |
|
199 |
root |
1.49 |
unsigned int |
200 |
root |
1.51 |
basecoder::decode_len (unsigned int len) const |
201 |
pcg |
1.2 |
{ |
202 |
pcg |
1.8 |
while (len && !dec_len [len]) |
203 |
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--len; |
204 |
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205 |
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return dec_len [len]; |
206 |
pcg |
1.2 |
} |
207 |
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208 |
root |
1.49 |
unsigned int |
209 |
root |
1.51 |
basecoder::encode (char *dst, u8 *src, unsigned int len) const |
210 |
pcg |
1.2 |
{ |
211 |
pcg |
1.10 |
if (!len || len > MAX_DEC_LEN) |
212 |
pcg |
1.8 |
return 0; |
213 |
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214 |
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int elen = encode_len (len); |
215 |
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216 |
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mp_limb_t m [MAX_LIMBS]; |
217 |
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mp_size_t n; |
218 |
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219 |
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u8 dst_ [MAX_ENC_LEN]; |
220 |
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221 |
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n = mpn_set_str (m, src, len, 256); |
222 |
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n = mpn_get_str (dst_, cmap.size, m, n); |
223 |
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224 |
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int plen = elen; // for padding |
225 |
pcg |
1.2 |
|
226 |
pcg |
1.8 |
while (n < plen) |
227 |
pcg |
1.2 |
{ |
228 |
pcg |
1.8 |
*dst++ = cmap.encode [0]; |
229 |
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plen--; |
230 |
pcg |
1.2 |
} |
231 |
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|
232 |
pcg |
1.8 |
for (unsigned int i = n - plen; i < n; ++i) |
233 |
|
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*dst++ = cmap.encode [dst_ [i]]; |
234 |
pcg |
1.4 |
|
235 |
pcg |
1.8 |
return elen; |
236 |
pcg |
1.2 |
} |
237 |
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|
238 |
root |
1.49 |
unsigned int |
239 |
root |
1.51 |
basecoder::decode (u8 *dst, char *src, unsigned int len) const |
240 |
pcg |
1.2 |
{ |
241 |
pcg |
1.10 |
if (!len || len > MAX_ENC_LEN) |
242 |
pcg |
1.8 |
return 0; |
243 |
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|
244 |
|
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u8 src_ [MAX_ENC_LEN]; |
245 |
|
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unsigned int elen = 0; |
246 |
pcg |
1.2 |
|
247 |
|
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while (len--) |
248 |
|
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{ |
249 |
pcg |
1.8 |
u8 val = cmap.decode [(u8)*src++]; |
250 |
pcg |
1.2 |
|
251 |
pcg |
1.8 |
if (val != charmap::INVALID) |
252 |
|
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src_ [elen++] = val; |
253 |
|
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} |
254 |
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|
255 |
|
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int dlen = decode_len (elen); |
256 |
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|
257 |
|
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mp_limb_t m [MAX_LIMBS]; |
258 |
|
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mp_size_t n; |
259 |
|
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|
260 |
|
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u8 dst_ [MAX_DEC_LEN]; |
261 |
pcg |
1.2 |
|
262 |
pcg |
1.8 |
n = mpn_set_str (m, src_, elen, cmap.size); |
263 |
|
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n = mpn_get_str (dst_, 256, m, n); |
264 |
pcg |
1.2 |
|
265 |
pcg |
1.8 |
if (n < dlen) |
266 |
|
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{ |
267 |
|
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memset (dst, 0, dlen - n); |
268 |
|
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memcpy (dst + dlen - n, dst_, n); |
269 |
pcg |
1.2 |
} |
270 |
pcg |
1.8 |
else |
271 |
|
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memcpy (dst, dst_ + n - dlen, dlen); |
272 |
pcg |
1.4 |
|
273 |
pcg |
1.8 |
return dlen; |
274 |
|
|
} |
275 |
|
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|
276 |
|
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#if 0 |
277 |
|
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struct test { test (); } test; |
278 |
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|
279 |
|
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test::test () |
280 |
|
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{ |
281 |
|
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basecoder cdc ("0123456789abcdefghijklmnopqrstuvwxyz"); |
282 |
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|
283 |
|
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u8 in[] = "0123456789abcdefghijklmnopqrstuvwxyz"; |
284 |
|
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static char enc[200]; |
285 |
|
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static u8 dec[200]; |
286 |
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|
287 |
|
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for (int i = 1; i < 20; i++) |
288 |
|
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{ |
289 |
|
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int elen = cdc.encode (enc, in, i); |
290 |
|
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int dlen = cdc.decode (dec, enc, elen); |
291 |
|
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|
292 |
|
|
printf ("%d>%d>%d (%s>%s)\n", i, elen, dlen, enc, dec); |
293 |
|
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} |
294 |
|
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abort (); |
295 |
|
|
} |
296 |
|
|
#endif |
297 |
|
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|
298 |
root |
1.51 |
static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI"); // a-zA-Z0-9 |
299 |
|
|
static basecoder cdc36 ("dPhZr06QmJkB34tSvL81xAeF92wGyO57uCnI"); // a-z0-9 for case-changers |
300 |
|
|
static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyOuCnI"); // a-z |
301 |
pcg |
1.8 |
|
302 |
|
|
///////////////////////////////////////////////////////////////////////////// |
303 |
|
|
|
304 |
root |
1.51 |
#define HDRSIZE 5 |
305 |
pcg |
1.24 |
|
306 |
root |
1.49 |
inline void |
307 |
|
|
encode_header (char *data, int clientid, int seqno, int retry = 0) |
308 |
pcg |
1.8 |
{ |
309 |
root |
1.51 |
assert (clientid < 256); |
310 |
|
|
|
311 |
pcg |
1.17 |
seqno &= SEQNO_MASK; |
312 |
|
|
|
313 |
|
|
u8 hdr[3] = { |
314 |
root |
1.51 |
seqno, |
315 |
|
|
(seqno >> 8) | (retry << 6), |
316 |
pcg |
1.17 |
clientid, |
317 |
|
|
}; |
318 |
pcg |
1.8 |
|
319 |
root |
1.51 |
cdc36.encode (data, hdr, 3); |
320 |
pcg |
1.8 |
} |
321 |
|
|
|
322 |
root |
1.49 |
inline void |
323 |
|
|
decode_header (char *data, int &clientid, int &seqno) |
324 |
pcg |
1.8 |
{ |
325 |
|
|
u8 hdr[3]; |
326 |
|
|
|
327 |
root |
1.51 |
cdc36.decode (hdr, data, HDRSIZE); |
328 |
pcg |
1.8 |
|
329 |
root |
1.51 |
clientid = hdr[2]; |
330 |
|
|
seqno = ((hdr[1] << 8) | hdr[0]) & SEQNO_MASK; |
331 |
pcg |
1.4 |
} |
332 |
|
|
|
333 |
|
|
///////////////////////////////////////////////////////////////////////////// |
334 |
|
|
|
335 |
|
|
struct byte_stream |
336 |
|
|
{ |
337 |
|
|
u8 *data; |
338 |
|
|
int maxsize; |
339 |
|
|
int fill; |
340 |
|
|
|
341 |
|
|
byte_stream (int maxsize); |
342 |
|
|
~byte_stream (); |
343 |
|
|
|
344 |
|
|
bool empty () { return !fill; } |
345 |
|
|
int size () { return fill; } |
346 |
|
|
|
347 |
pcg |
1.5 |
bool put (u8 *data, unsigned int datalen); |
348 |
pcg |
1.4 |
bool put (vpn_packet *pkt); |
349 |
|
|
vpn_packet *get (); |
350 |
|
|
|
351 |
|
|
u8 *begin () { return data; } |
352 |
|
|
void remove (int count); |
353 |
|
|
}; |
354 |
|
|
|
355 |
|
|
byte_stream::byte_stream (int maxsize) |
356 |
|
|
: maxsize (maxsize), fill (0) |
357 |
|
|
{ |
358 |
|
|
data = new u8 [maxsize]; |
359 |
|
|
} |
360 |
|
|
|
361 |
|
|
byte_stream::~byte_stream () |
362 |
|
|
{ |
363 |
|
|
delete data; |
364 |
|
|
} |
365 |
|
|
|
366 |
root |
1.49 |
void |
367 |
|
|
byte_stream::remove (int count) |
368 |
pcg |
1.4 |
{ |
369 |
|
|
if (count > fill) |
370 |
pcg |
1.17 |
assert (count <= fill); |
371 |
pcg |
1.4 |
|
372 |
|
|
memmove (data, data + count, fill -= count); |
373 |
|
|
} |
374 |
|
|
|
375 |
root |
1.49 |
bool |
376 |
|
|
byte_stream::put (u8 *data, unsigned int datalen) |
377 |
pcg |
1.5 |
{ |
378 |
|
|
if (maxsize - fill < datalen) |
379 |
|
|
return false; |
380 |
|
|
|
381 |
|
|
memcpy (this->data + fill, data, datalen); fill += datalen; |
382 |
|
|
|
383 |
|
|
return true; |
384 |
|
|
} |
385 |
|
|
|
386 |
root |
1.49 |
bool |
387 |
|
|
byte_stream::put (vpn_packet *pkt) |
388 |
pcg |
1.4 |
{ |
389 |
|
|
if (maxsize - fill < pkt->len + 2) |
390 |
|
|
return false; |
391 |
|
|
|
392 |
|
|
data [fill++] = pkt->len >> 8; |
393 |
|
|
data [fill++] = pkt->len; |
394 |
|
|
|
395 |
pcg |
1.10 |
memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len; |
396 |
pcg |
1.4 |
|
397 |
|
|
return true; |
398 |
|
|
} |
399 |
|
|
|
400 |
|
|
vpn_packet *byte_stream::get () |
401 |
|
|
{ |
402 |
pcg |
1.18 |
unsigned int len; |
403 |
|
|
|
404 |
|
|
for (;;) |
405 |
|
|
{ |
406 |
|
|
len = (data [0] << 8) | data [1]; |
407 |
pcg |
1.4 |
|
408 |
pcg |
1.18 |
if (len <= MAXSIZE || fill < 2) |
409 |
|
|
break; |
410 |
pcg |
1.5 |
|
411 |
pcg |
1.18 |
// TODO: handle this better than skipping, e.g. by reset |
412 |
|
|
slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte...")); |
413 |
|
|
remove (1); |
414 |
|
|
} |
415 |
|
|
|
416 |
pcg |
1.4 |
if (fill < len + 2) |
417 |
|
|
return 0; |
418 |
|
|
|
419 |
|
|
vpn_packet *pkt = new vpn_packet; |
420 |
pcg |
1.5 |
|
421 |
|
|
pkt->len = len; |
422 |
pcg |
1.10 |
memcpy (pkt->at (0), data + 2, len); |
423 |
pcg |
1.4 |
remove (len + 2); |
424 |
|
|
|
425 |
|
|
return pkt; |
426 |
pcg |
1.2 |
} |
427 |
|
|
|
428 |
pcg |
1.3 |
///////////////////////////////////////////////////////////////////////////// |
429 |
|
|
|
430 |
pcg |
1.2 |
#define FLAG_QUERY ( 0 << 15) |
431 |
|
|
#define FLAG_RESPONSE ( 1 << 15) |
432 |
pcg |
1.9 |
#define FLAG_OP_MASK (15 << 11) |
433 |
pcg |
1.2 |
#define FLAG_OP_QUERY ( 0 << 11) |
434 |
|
|
#define FLAG_AA ( 1 << 10) |
435 |
|
|
#define FLAG_TC ( 1 << 9) |
436 |
|
|
#define FLAG_RD ( 1 << 8) |
437 |
|
|
#define FLAG_RA ( 1 << 7) |
438 |
pcg |
1.5 |
#define FLAG_AUTH ( 1 << 5) |
439 |
pcg |
1.2 |
#define FLAG_RCODE_MASK (15 << 0) |
440 |
|
|
#define FLAG_RCODE_OK ( 0 << 0) |
441 |
|
|
#define FLAG_RCODE_FORMERR ( 1 << 0) |
442 |
|
|
#define FLAG_RCODE_SERVFAIL ( 2 << 0) |
443 |
|
|
#define FLAG_RCODE_NXDOMAIN ( 3 << 0) |
444 |
|
|
#define FLAG_RCODE_REFUSED ( 5 << 0) |
445 |
|
|
|
446 |
|
|
#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY | FLAG_OP_QUERY | FLAG_RD) |
447 |
pcg |
1.5 |
#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE | FLAG_OP_QUERY | FLAG_AA | FLAG_RD | FLAG_RA) |
448 |
pcg |
1.2 |
|
449 |
pcg |
1.10 |
struct dns_cfg |
450 |
|
|
{ |
451 |
|
|
static int next_uid; |
452 |
|
|
|
453 |
root |
1.51 |
u8 chksum; |
454 |
|
|
u8 rrtype; |
455 |
|
|
u16 uid; // to make request unique |
456 |
pcg |
1.24 |
|
457 |
pcg |
1.10 |
u8 version; |
458 |
pcg |
1.24 |
u8 flags; |
459 |
root |
1.51 |
u16 max_size; |
460 |
|
|
|
461 |
|
|
u8 id1, id2, id3, id4; |
462 |
pcg |
1.24 |
|
463 |
pcg |
1.10 |
u16 client; |
464 |
root |
1.51 |
u8 def_ttl; |
465 |
|
|
u8 r0; |
466 |
pcg |
1.10 |
|
467 |
root |
1.51 |
u8 syn_cdc; // cdc en/decoder for syn (A?) requests |
468 |
|
|
u8 hdr_cdc; // cdc en/decoder for regular request headers |
469 |
|
|
u8 req_cdc; // cdc en/decoder for regular (ANY?) request data |
470 |
|
|
u8 rep_cdc; // cdc en/decoder for regular (TXT) replies, 0 == 8 bit encoding |
471 |
pcg |
1.24 |
|
472 |
root |
1.51 |
u8 r1, r2, r3, r4; |
473 |
pcg |
1.10 |
|
474 |
|
|
void reset (int clientid); |
475 |
|
|
bool valid (); |
476 |
root |
1.51 |
u8 get_chksum (); |
477 |
pcg |
1.10 |
}; |
478 |
|
|
|
479 |
|
|
int dns_cfg::next_uid; |
480 |
|
|
|
481 |
root |
1.49 |
void |
482 |
|
|
dns_cfg::reset (int clientid) |
483 |
pcg |
1.10 |
{ |
484 |
root |
1.51 |
// this ID must result in some mixed-case characters in cdc26-encoding |
485 |
pcg |
1.10 |
id1 = 'G'; |
486 |
|
|
id2 = 'V'; |
487 |
|
|
id3 = 'P'; |
488 |
|
|
id4 = 'E'; |
489 |
|
|
|
490 |
root |
1.51 |
version = 2; |
491 |
pcg |
1.10 |
|
492 |
|
|
rrtype = RR_TYPE_TXT; |
493 |
|
|
flags = 0; |
494 |
pcg |
1.24 |
def_ttl = 0; |
495 |
root |
1.51 |
syn_cdc = 26; |
496 |
|
|
hdr_cdc = 36; |
497 |
|
|
req_cdc = conf.dns_case_preserving ? 62 : 36; |
498 |
pcg |
1.24 |
rep_cdc = 0; |
499 |
pcg |
1.27 |
max_size = htons (MAX_PKT_SIZE); |
500 |
|
|
client = htons (clientid); |
501 |
root |
1.51 |
uid = ++next_uid; |
502 |
|
|
|
503 |
|
|
r0 = r1 = r2 = r3 = r4 = 0; |
504 |
pcg |
1.10 |
|
505 |
root |
1.51 |
chksum = get_chksum (); |
506 |
|
|
} |
507 |
|
|
|
508 |
|
|
// simple but not trivial chksum |
509 |
|
|
u8 |
510 |
|
|
dns_cfg::get_chksum () |
511 |
|
|
{ |
512 |
|
|
unsigned int sum = 0xff00; // only 16 bits required |
513 |
|
|
|
514 |
|
|
u8 old_chksum = chksum; |
515 |
|
|
chksum = 0; |
516 |
|
|
|
517 |
|
|
for (unsigned int i = 0; i < sizeof (*this); ++i) |
518 |
|
|
sum += ((u8 *)this)[i] * (i + 1); |
519 |
|
|
|
520 |
|
|
chksum = old_chksum; |
521 |
|
|
|
522 |
|
|
return sum + (sum >> 8); |
523 |
pcg |
1.10 |
} |
524 |
|
|
|
525 |
root |
1.49 |
bool |
526 |
|
|
dns_cfg::valid () |
527 |
pcg |
1.10 |
{ |
528 |
pcg |
1.40 |
// although the protocol itself allows for some configurability, |
529 |
|
|
// only the following encoding/decoding settings are implemented. |
530 |
pcg |
1.10 |
return id1 == 'G' |
531 |
|
|
&& id2 == 'V' |
532 |
|
|
&& id3 == 'P' |
533 |
|
|
&& id4 == 'E' |
534 |
root |
1.51 |
&& version == 2 |
535 |
|
|
&& syn_cdc == 26 |
536 |
|
|
&& hdr_cdc == 36 |
537 |
|
|
&& (req_cdc == 36 || req_cdc == 62) |
538 |
pcg |
1.24 |
&& rep_cdc == 0 |
539 |
root |
1.51 |
&& chksum == get_chksum (); |
540 |
pcg |
1.10 |
} |
541 |
|
|
|
542 |
pcg |
1.2 |
struct dns_packet : net_packet |
543 |
|
|
{ |
544 |
|
|
u16 id; |
545 |
|
|
u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 |
546 |
|
|
u16 qdcount, ancount, nscount, arcount; |
547 |
|
|
|
548 |
pcg |
1.24 |
u8 data [MAXSIZE - 6 * 2]; |
549 |
pcg |
1.2 |
|
550 |
|
|
int decode_label (char *data, int size, int &offs); |
551 |
|
|
}; |
552 |
|
|
|
553 |
root |
1.49 |
int |
554 |
|
|
dns_packet::decode_label (char *data, int size, int &offs) |
555 |
pcg |
1.2 |
{ |
556 |
|
|
char *orig = data; |
557 |
|
|
|
558 |
|
|
memset (data, 0, size); |
559 |
|
|
|
560 |
|
|
while (offs < size - 1) |
561 |
|
|
{ |
562 |
|
|
u8 len = (*this)[offs++]; |
563 |
|
|
|
564 |
|
|
if (!len) |
565 |
|
|
break; |
566 |
|
|
else if (len < 64) |
567 |
|
|
{ |
568 |
|
|
if (size < len + 1 || offs + len >= MAXSIZE - 1) |
569 |
|
|
break; |
570 |
|
|
|
571 |
|
|
memcpy (data, &((*this)[offs]), len); |
572 |
|
|
|
573 |
|
|
data += len; size -= len; offs += len; |
574 |
|
|
*data++ = '.'; size--; |
575 |
|
|
} |
576 |
|
|
else |
577 |
|
|
{ |
578 |
|
|
int offs2 = ((len & 63) << 8) + (*this)[offs++]; |
579 |
|
|
|
580 |
|
|
data += decode_label (data, size, offs2); |
581 |
|
|
break; |
582 |
|
|
} |
583 |
|
|
} |
584 |
|
|
|
585 |
|
|
return data - orig; |
586 |
|
|
} |
587 |
|
|
|
588 |
pcg |
1.3 |
///////////////////////////////////////////////////////////////////////////// |
589 |
|
|
|
590 |
root |
1.49 |
static |
591 |
|
|
u16 next_id () |
592 |
|
|
{ |
593 |
|
|
static u16 dns_id = 0; // TODO: should be per-vpn |
594 |
pcg |
1.18 |
|
595 |
|
|
if (!dns_id) |
596 |
|
|
dns_id = time (0); |
597 |
|
|
|
598 |
|
|
// the simplest lsfr with periodicity 65535 i could find |
599 |
|
|
dns_id = (dns_id << 1) |
600 |
|
|
| (((dns_id >> 1) |
601 |
|
|
^ (dns_id >> 2) |
602 |
|
|
^ (dns_id >> 4) |
603 |
|
|
^ (dns_id >> 15)) & 1); |
604 |
|
|
|
605 |
|
|
return dns_id; |
606 |
|
|
} |
607 |
|
|
|
608 |
|
|
struct dns_rcv; |
609 |
|
|
struct dns_snd; |
610 |
|
|
|
611 |
|
|
struct dns_connection |
612 |
|
|
{ |
613 |
|
|
connection *c; |
614 |
|
|
struct vpn *vpn; |
615 |
|
|
|
616 |
|
|
dns_cfg cfg; |
617 |
|
|
|
618 |
|
|
bool established; |
619 |
root |
1.51 |
const basecoder *cdc; |
620 |
pcg |
1.18 |
|
621 |
|
|
tstamp last_received; |
622 |
|
|
tstamp last_sent; |
623 |
pcg |
1.25 |
double min_latency; |
624 |
pcg |
1.18 |
double poll_interval, send_interval; |
625 |
|
|
|
626 |
|
|
vector<dns_rcv *> rcvpq; |
627 |
|
|
|
628 |
pcg |
1.31 |
byte_stream rcvdq; int rcvseq; int repseq; |
629 |
pcg |
1.18 |
byte_stream snddq; int sndseq; |
630 |
|
|
|
631 |
pcg |
1.46 |
inline void time_cb (ev::timer &w, int revents); ev::timer tw; |
632 |
pcg |
1.18 |
void receive_rep (dns_rcv *r); |
633 |
|
|
|
634 |
root |
1.51 |
void reset (); // quite like tcp RST |
635 |
|
|
void set_cfg (); // to be called after any cfg changes |
636 |
|
|
|
637 |
pcg |
1.18 |
dns_connection (connection *c); |
638 |
|
|
~dns_connection (); |
639 |
|
|
}; |
640 |
|
|
|
641 |
pcg |
1.10 |
struct dns_snd |
642 |
pcg |
1.3 |
{ |
643 |
|
|
dns_packet *pkt; |
644 |
pcg |
1.10 |
tstamp timeout, sent; |
645 |
pcg |
1.3 |
int retry; |
646 |
pcg |
1.9 |
struct dns_connection *dns; |
647 |
pcg |
1.5 |
int seqno; |
648 |
pcg |
1.17 |
bool stdhdr; |
649 |
pcg |
1.3 |
|
650 |
pcg |
1.9 |
void gen_stream_req (int seqno, byte_stream &stream); |
651 |
pcg |
1.18 |
void gen_syn_req (); |
652 |
pcg |
1.11 |
|
653 |
|
|
dns_snd (dns_connection *dns); |
654 |
|
|
~dns_snd (); |
655 |
pcg |
1.3 |
}; |
656 |
|
|
|
657 |
pcg |
1.10 |
dns_snd::dns_snd (dns_connection *dns) |
658 |
pcg |
1.9 |
: dns (dns) |
659 |
pcg |
1.3 |
{ |
660 |
pcg |
1.10 |
timeout = 0; |
661 |
pcg |
1.3 |
retry = 0; |
662 |
pcg |
1.10 |
seqno = 0; |
663 |
pcg |
1.43 |
sent = ev_now (); |
664 |
pcg |
1.17 |
stdhdr = false; |
665 |
pcg |
1.3 |
|
666 |
|
|
pkt = new dns_packet; |
667 |
|
|
|
668 |
pcg |
1.5 |
pkt->id = next_id (); |
669 |
|
|
} |
670 |
|
|
|
671 |
pcg |
1.11 |
dns_snd::~dns_snd () |
672 |
|
|
{ |
673 |
|
|
delete pkt; |
674 |
|
|
} |
675 |
|
|
|
676 |
root |
1.49 |
static void |
677 |
|
|
append_domain (dns_packet &pkt, int &offs, const char *domain) |
678 |
pcg |
1.10 |
{ |
679 |
|
|
// add tunnel domain |
680 |
|
|
for (;;) |
681 |
|
|
{ |
682 |
|
|
const char *end = strchr (domain, '.'); |
683 |
|
|
|
684 |
|
|
if (!end) |
685 |
|
|
end = domain + strlen (domain); |
686 |
|
|
|
687 |
|
|
int len = end - domain; |
688 |
|
|
|
689 |
|
|
pkt [offs++] = len; |
690 |
|
|
memcpy (pkt.at (offs), domain, len); |
691 |
|
|
offs += len; |
692 |
|
|
|
693 |
|
|
if (!*end) |
694 |
|
|
break; |
695 |
|
|
|
696 |
|
|
domain = end + 1; |
697 |
|
|
} |
698 |
|
|
} |
699 |
|
|
|
700 |
root |
1.49 |
void |
701 |
|
|
dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
702 |
pcg |
1.5 |
{ |
703 |
pcg |
1.17 |
stdhdr = true; |
704 |
pcg |
1.5 |
this->seqno = seqno; |
705 |
|
|
|
706 |
pcg |
1.43 |
timeout = ev_now () + INITIAL_TIMEOUT; |
707 |
pcg |
1.10 |
|
708 |
pcg |
1.5 |
pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
709 |
pcg |
1.4 |
pkt->qdcount = htons (1); |
710 |
pcg |
1.3 |
|
711 |
pcg |
1.4 |
int offs = 6*2; |
712 |
pcg |
1.19 |
int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2); |
713 |
pcg |
1.5 |
// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, |
714 |
|
|
// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra |
715 |
|
|
|
716 |
pcg |
1.8 |
char enc[256], *encp = enc; |
717 |
|
|
encode_header (enc, THISNODE->id, seqno); |
718 |
pcg |
1.4 |
|
719 |
root |
1.51 |
int datalen = dns->cdc->decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE); |
720 |
pcg |
1.4 |
|
721 |
pcg |
1.9 |
if (datalen > stream.size ()) |
722 |
|
|
datalen = stream.size (); |
723 |
pcg |
1.8 |
|
724 |
root |
1.51 |
int enclen = dns->cdc->encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE; |
725 |
pcg |
1.9 |
stream.remove (datalen); |
726 |
pcg |
1.4 |
|
727 |
pcg |
1.5 |
while (enclen) |
728 |
|
|
{ |
729 |
|
|
int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE; |
730 |
|
|
|
731 |
|
|
(*pkt)[offs++] = lbllen; |
732 |
|
|
memcpy (pkt->at (offs), encp, lbllen); |
733 |
pcg |
1.4 |
|
734 |
pcg |
1.5 |
offs += lbllen; |
735 |
|
|
encp += lbllen; |
736 |
pcg |
1.4 |
|
737 |
pcg |
1.5 |
enclen -= lbllen; |
738 |
pcg |
1.4 |
} |
739 |
|
|
|
740 |
pcg |
1.19 |
append_domain (*pkt, offs, dns->c->conf->domain); |
741 |
pcg |
1.3 |
|
742 |
pcg |
1.10 |
(*pkt)[offs++] = 0; |
743 |
|
|
(*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; |
744 |
|
|
(*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
745 |
|
|
|
746 |
|
|
pkt->len = offs; |
747 |
|
|
} |
748 |
|
|
|
749 |
root |
1.49 |
void |
750 |
|
|
dns_snd::gen_syn_req () |
751 |
pcg |
1.10 |
{ |
752 |
pcg |
1.43 |
timeout = ev_now () + INITIAL_SYN_TIMEOUT; |
753 |
pcg |
1.4 |
|
754 |
pcg |
1.10 |
pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
755 |
|
|
pkt->qdcount = htons (1); |
756 |
pcg |
1.4 |
|
757 |
pcg |
1.18 |
int offs = 6 * 2; |
758 |
pcg |
1.4 |
|
759 |
pcg |
1.18 |
int elen = cdc26.encode ((char *)pkt->at (offs + 1), (u8 *)&dns->cfg, sizeof (dns_cfg)); |
760 |
pcg |
1.4 |
|
761 |
pcg |
1.10 |
assert (elen <= MAX_LBL_SIZE); |
762 |
pcg |
1.4 |
|
763 |
pcg |
1.10 |
(*pkt)[offs] = elen; |
764 |
|
|
offs += elen + 1; |
765 |
pcg |
1.19 |
append_domain (*pkt, offs, dns->c->conf->domain); |
766 |
pcg |
1.4 |
|
767 |
|
|
(*pkt)[offs++] = 0; |
768 |
pcg |
1.10 |
(*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; |
769 |
pcg |
1.4 |
(*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; |
770 |
|
|
|
771 |
|
|
pkt->len = offs; |
772 |
pcg |
1.5 |
} |
773 |
|
|
|
774 |
|
|
struct dns_rcv |
775 |
|
|
{ |
776 |
|
|
int seqno; |
777 |
|
|
dns_packet *pkt; // reply packet |
778 |
|
|
u8 data [MAXSIZE]; // actually part of the reply packet... |
779 |
|
|
int datalen; |
780 |
|
|
|
781 |
pcg |
1.6 |
dns_rcv (int seqno, u8 *data, int datalen); |
782 |
pcg |
1.5 |
~dns_rcv (); |
783 |
|
|
}; |
784 |
|
|
|
785 |
pcg |
1.6 |
dns_rcv::dns_rcv (int seqno, u8 *data, int datalen) |
786 |
pcg |
1.5 |
: seqno (seqno), pkt (new dns_packet), datalen (datalen) |
787 |
|
|
{ |
788 |
|
|
memcpy (this->data, data, datalen); |
789 |
|
|
} |
790 |
pcg |
1.4 |
|
791 |
pcg |
1.5 |
dns_rcv::~dns_rcv () |
792 |
|
|
{ |
793 |
|
|
delete pkt; |
794 |
pcg |
1.3 |
} |
795 |
|
|
|
796 |
|
|
///////////////////////////////////////////////////////////////////////////// |
797 |
pcg |
1.9 |
|
798 |
|
|
dns_connection::dns_connection (connection *c) |
799 |
|
|
: c (c) |
800 |
|
|
, rcvdq (MAX_BACKLOG * 2) |
801 |
pcg |
1.31 |
, snddq (MAX_BACKLOG) |
802 |
pcg |
1.9 |
{ |
803 |
pcg |
1.45 |
tw.set<dns_connection, &dns_connection::time_cb> (this); |
804 |
|
|
|
805 |
pcg |
1.9 |
vpn = c->vpn; |
806 |
|
|
|
807 |
root |
1.51 |
reset (); |
808 |
|
|
} |
809 |
|
|
|
810 |
|
|
dns_connection::~dns_connection () |
811 |
|
|
{ |
812 |
|
|
reset (); |
813 |
|
|
} |
814 |
|
|
|
815 |
|
|
void |
816 |
|
|
dns_connection::reset () |
817 |
|
|
{ |
818 |
|
|
while (!rcvpq.empty ()) |
819 |
|
|
{ |
820 |
|
|
delete rcvpq.back (); |
821 |
|
|
rcvpq.pop_back (); |
822 |
|
|
} |
823 |
|
|
|
824 |
|
|
for (int i = vpn->dns_sndpq.size (); i--; ) |
825 |
|
|
if (vpn->dns_sndpq [i]->dns == this) |
826 |
|
|
{ |
827 |
|
|
vpn->dns_sndpq [i] = vpn->dns_sndpq.back (); |
828 |
|
|
vpn->dns_sndpq.pop_back (); |
829 |
|
|
} |
830 |
|
|
|
831 |
pcg |
1.10 |
established = false; |
832 |
|
|
|
833 |
pcg |
1.31 |
rcvseq = repseq = sndseq = 0; |
834 |
pcg |
1.10 |
|
835 |
root |
1.52 |
last_sent = 0; |
836 |
pcg |
1.30 |
poll_interval = 0.5; // starting here |
837 |
pcg |
1.17 |
send_interval = 0.5; // starting rate |
838 |
pcg |
1.25 |
min_latency = INITIAL_TIMEOUT; |
839 |
pcg |
1.9 |
} |
840 |
|
|
|
841 |
root |
1.51 |
void |
842 |
|
|
dns_connection::set_cfg () |
843 |
pcg |
1.9 |
{ |
844 |
root |
1.51 |
cdc = cfg.req_cdc == 36 ? &cdc36 : &cdc62; |
845 |
pcg |
1.9 |
} |
846 |
pcg |
1.3 |
|
847 |
root |
1.49 |
void |
848 |
|
|
dns_connection::receive_rep (dns_rcv *r) |
849 |
pcg |
1.2 |
{ |
850 |
pcg |
1.10 |
if (r->datalen) |
851 |
root |
1.52 |
poll_interval = max (poll_interval * (1. / 1.2), MIN_POLL_INTERVAL); |
852 |
pcg |
1.10 |
else |
853 |
root |
1.52 |
poll_interval = min (poll_interval * 1.1, MAX_POLL_INTERVAL); |
854 |
pcg |
1.2 |
|
855 |
pcg |
1.9 |
rcvpq.push_back (r); |
856 |
pcg |
1.5 |
|
857 |
|
|
redo: |
858 |
|
|
|
859 |
pcg |
1.8 |
// find next packet |
860 |
pcg |
1.9 |
for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
861 |
|
|
if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
862 |
pcg |
1.5 |
{ |
863 |
pcg |
1.41 |
//printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D |
864 |
pcg |
1.8 |
// enter the packet into our input stream |
865 |
|
|
r = *i; |
866 |
|
|
|
867 |
|
|
// remove the oldest packet, look forward, as it's oldest first |
868 |
pcg |
1.9 |
for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
869 |
|
|
if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
870 |
pcg |
1.8 |
{ |
871 |
pcg |
1.41 |
//printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D |
872 |
pcg |
1.8 |
delete *j; |
873 |
pcg |
1.9 |
rcvpq.erase (j); |
874 |
pcg |
1.8 |
break; |
875 |
|
|
} |
876 |
pcg |
1.5 |
|
877 |
pcg |
1.9 |
rcvseq = (rcvseq + 1) & SEQNO_MASK; |
878 |
pcg |
1.5 |
|
879 |
pcg |
1.9 |
if (!rcvdq.put (r->data, r->datalen)) |
880 |
pcg |
1.17 |
{ |
881 |
root |
1.50 |
// MUST never overflow, can be caused by data corruption, TODO |
882 |
|
|
slog (L_CRIT, "DNS: !rcvdq.put (r->data, r->datalen)"); |
883 |
root |
1.51 |
reset (); |
884 |
root |
1.50 |
return; |
885 |
pcg |
1.17 |
} |
886 |
pcg |
1.5 |
|
887 |
pcg |
1.9 |
while (vpn_packet *pkt = rcvdq.get ()) |
888 |
pcg |
1.5 |
{ |
889 |
|
|
sockinfo si; |
890 |
pcg |
1.33 |
si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; |
891 |
pcg |
1.5 |
|
892 |
|
|
vpn->recv_vpn_packet (pkt, si); |
893 |
pcg |
1.11 |
delete pkt; |
894 |
pcg |
1.5 |
} |
895 |
pcg |
1.8 |
|
896 |
|
|
// check for further packets |
897 |
pcg |
1.5 |
goto redo; |
898 |
|
|
} |
899 |
|
|
} |
900 |
|
|
|
901 |
pcg |
1.10 |
void |
902 |
|
|
vpn::dnsv4_server (dns_packet &pkt) |
903 |
pcg |
1.2 |
{ |
904 |
pcg |
1.10 |
u16 flags = ntohs (pkt.flags); |
905 |
pcg |
1.2 |
|
906 |
pcg |
1.4 |
int offs = 6 * 2; // skip header |
907 |
pcg |
1.2 |
|
908 |
pcg |
1.10 |
pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
909 |
pcg |
1.2 |
|
910 |
pcg |
1.10 |
if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) |
911 |
|
|
&& pkt.qdcount == htons (1)) |
912 |
pcg |
1.4 |
{ |
913 |
pcg |
1.24 |
char qname [MAXSIZE]; |
914 |
pcg |
1.10 |
int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); |
915 |
pcg |
1.4 |
|
916 |
pcg |
1.10 |
u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; |
917 |
|
|
u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; |
918 |
pcg |
1.2 |
|
919 |
pcg |
1.10 |
pkt.qdcount = htons (1); |
920 |
|
|
pkt.ancount = 0; |
921 |
|
|
pkt.nscount = 0; // should be self, as other nameservers reply like this |
922 |
|
|
pkt.arcount = 0; // a record for self, as other nameservers reply like this |
923 |
pcg |
1.2 |
|
924 |
pcg |
1.16 |
pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_SERVFAIL); |
925 |
pcg |
1.2 |
|
926 |
pcg |
1.4 |
int dlen = strlen (THISNODE->domain); |
927 |
pcg |
1.2 |
|
928 |
pcg |
1.4 |
if (qclass == RR_CLASS_IN |
929 |
pcg |
1.10 |
&& qlen > dlen + 1 |
930 |
pcg |
1.24 |
&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen)) |
931 |
pcg |
1.2 |
{ |
932 |
pcg |
1.10 |
// now generate reply |
933 |
|
|
pkt.ancount = htons (1); // one answer RR |
934 |
|
|
pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); |
935 |
|
|
|
936 |
|
|
if ((qtype == RR_TYPE_ANY |
937 |
|
|
|| qtype == RR_TYPE_TXT |
938 |
|
|
|| qtype == RR_TYPE_NULL) |
939 |
|
|
&& qlen > dlen + 1 + HDRSIZE) |
940 |
pcg |
1.5 |
{ |
941 |
pcg |
1.10 |
// correct class, domain: parse |
942 |
|
|
int client, seqno; |
943 |
|
|
decode_header (qname, client, seqno); |
944 |
pcg |
1.5 |
|
945 |
pcg |
1.10 |
if (0 < client && client <= conns.size ()) |
946 |
|
|
{ |
947 |
|
|
connection *c = conns [client - 1]; |
948 |
|
|
dns_connection *dns = c->dns; |
949 |
|
|
dns_rcv *rcv; |
950 |
|
|
|
951 |
|
|
if (dns) |
952 |
|
|
{ |
953 |
root |
1.51 |
u8 data[MAXSIZE]; |
954 |
|
|
int datalen = dns->cdc->decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE)); |
955 |
|
|
|
956 |
pcg |
1.10 |
for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) |
957 |
|
|
if (SEQNO_EQ ((*i)->seqno, seqno)) |
958 |
|
|
{ |
959 |
|
|
// already seen that request: simply reply with the cached reply |
960 |
|
|
dns_rcv *r = *i; |
961 |
|
|
|
962 |
pcg |
1.17 |
slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno); |
963 |
|
|
|
964 |
|
|
// refresh header & id, as the retry count could have changed |
965 |
|
|
memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE); |
966 |
|
|
r->pkt->id = pkt.id; |
967 |
pcg |
1.10 |
|
968 |
|
|
memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); |
969 |
pcg |
1.17 |
|
970 |
pcg |
1.10 |
goto duplicate_request; |
971 |
|
|
} |
972 |
|
|
|
973 |
|
|
// new packet, queue |
974 |
|
|
rcv = new dns_rcv (seqno, data, datalen); |
975 |
|
|
dns->receive_rep (rcv); |
976 |
|
|
} |
977 |
|
|
|
978 |
pcg |
1.21 |
{ |
979 |
|
|
pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section |
980 |
|
|
|
981 |
|
|
int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; |
982 |
|
|
pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type |
983 |
|
|
pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
984 |
|
|
pkt [offs++] = 0; pkt [offs++] = 0; |
985 |
|
|
pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL |
986 |
|
|
|
987 |
|
|
int rdlen_offs = offs += 2; |
988 |
pcg |
1.10 |
|
989 |
pcg |
1.21 |
if (dns) |
990 |
|
|
{ |
991 |
pcg |
1.27 |
int dlen = ntohs (dns->cfg.max_size) - offs; |
992 |
|
|
|
993 |
|
|
// bind doesn't compress well, so reduce further by one label length |
994 |
|
|
dlen -= qlen; |
995 |
|
|
|
996 |
pcg |
1.21 |
// only put data into in-order sequence packets, if |
997 |
|
|
// we receive out-of-order packets we generate empty |
998 |
|
|
// replies |
999 |
pcg |
1.31 |
//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D |
1000 |
|
|
if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW) |
1001 |
pcg |
1.21 |
{ |
1002 |
pcg |
1.31 |
dns->repseq = seqno; |
1003 |
pcg |
1.10 |
|
1004 |
pcg |
1.31 |
while (dlen > 1 && !dns->snddq.empty ()) |
1005 |
|
|
{ |
1006 |
|
|
int txtlen = dlen <= 255 ? dlen - 1 : 255; |
1007 |
|
|
|
1008 |
|
|
if (txtlen > dns->snddq.size ()) |
1009 |
|
|
txtlen = dns->snddq.size (); |
1010 |
|
|
|
1011 |
|
|
pkt[offs++] = txtlen; |
1012 |
|
|
memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); |
1013 |
|
|
offs += txtlen; |
1014 |
|
|
dns->snddq.remove (txtlen); |
1015 |
pcg |
1.10 |
|
1016 |
pcg |
1.31 |
dlen -= txtlen + 1; |
1017 |
|
|
} |
1018 |
pcg |
1.21 |
} |
1019 |
|
|
|
1020 |
pcg |
1.31 |
// avoid completely empty TXT rdata |
1021 |
pcg |
1.21 |
if (offs == rdlen_offs) |
1022 |
|
|
pkt[offs++] = 0; |
1023 |
pcg |
1.15 |
|
1024 |
pcg |
1.21 |
slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); |
1025 |
|
|
} |
1026 |
|
|
else |
1027 |
|
|
{ |
1028 |
|
|
// send RST |
1029 |
|
|
pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
1030 |
|
|
pkt [offs++] = CMD_IP_RST; |
1031 |
|
|
} |
1032 |
pcg |
1.10 |
|
1033 |
pcg |
1.21 |
int rdlen = offs - rdlen_offs; |
1034 |
pcg |
1.10 |
|
1035 |
pcg |
1.21 |
pkt [rdlen_offs - 2] = rdlen >> 8; |
1036 |
|
|
pkt [rdlen_offs - 1] = rdlen; |
1037 |
pcg |
1.10 |
|
1038 |
pcg |
1.21 |
if (dns) |
1039 |
|
|
{ |
1040 |
|
|
// now update dns_rcv copy |
1041 |
|
|
rcv->pkt->len = offs; |
1042 |
|
|
memcpy (rcv->pkt->at (0), pkt.at (0), offs); |
1043 |
|
|
} |
1044 |
|
|
} |
1045 |
pcg |
1.9 |
|
1046 |
pcg |
1.10 |
duplicate_request: ; |
1047 |
|
|
} |
1048 |
|
|
else |
1049 |
|
|
pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); |
1050 |
|
|
} |
1051 |
|
|
else if (qtype == RR_TYPE_A |
1052 |
|
|
&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg))) |
1053 |
|
|
{ |
1054 |
|
|
dns_cfg cfg; |
1055 |
|
|
cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg))); |
1056 |
|
|
int client = ntohs (cfg.client); |
1057 |
pcg |
1.4 |
|
1058 |
pcg |
1.10 |
pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section |
1059 |
pcg |
1.2 |
|
1060 |
pcg |
1.10 |
pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type |
1061 |
|
|
pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class |
1062 |
|
|
pkt [offs++] = 0; pkt [offs++] = 0; |
1063 |
|
|
pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL |
1064 |
|
|
pkt [offs++] = 0; pkt [offs++] = 4; // rdlength |
1065 |
pcg |
1.2 |
|
1066 |
pcg |
1.10 |
pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; |
1067 |
|
|
pkt [offs++] = CMD_IP_REJ; |
1068 |
pcg |
1.2 |
|
1069 |
pcg |
1.10 |
if (0 < client && client <= conns.size ()) |
1070 |
pcg |
1.5 |
{ |
1071 |
pcg |
1.10 |
connection *c = conns [client - 1]; |
1072 |
pcg |
1.2 |
|
1073 |
pcg |
1.10 |
if (cfg.valid ()) |
1074 |
|
|
{ |
1075 |
root |
1.51 |
slog (L_INFO, _("DNS: client %d connects (version %d, req_cdc %d)"), client, cfg.version, cfg.req_cdc); |
1076 |
|
|
|
1077 |
|
|
// check for any encoding mismatches - hints at a case problem |
1078 |
|
|
char qname2 [MAX_ENC_LEN]; |
1079 |
|
|
cdc26.encode (qname2, (u8 *)&cfg, sizeof (dns_cfg)); |
1080 |
pcg |
1.10 |
|
1081 |
|
|
delete c->dns; |
1082 |
root |
1.51 |
|
1083 |
|
|
pkt [offs - 1] = memcmp (qname, qname2, cdc26.encode_len (sizeof (dns_cfg))) |
1084 |
|
|
? CMD_IP_CSE : CMD_IP_SYN; |
1085 |
|
|
|
1086 |
pcg |
1.10 |
c->dns = new dns_connection (c); |
1087 |
|
|
c->dns->cfg = cfg; |
1088 |
root |
1.51 |
c->dns->set_cfg (); |
1089 |
pcg |
1.10 |
} |
1090 |
pcg |
1.5 |
} |
1091 |
|
|
} |
1092 |
pcg |
1.2 |
} |
1093 |
pcg |
1.6 |
|
1094 |
pcg |
1.10 |
pkt.len = offs; |
1095 |
pcg |
1.4 |
} |
1096 |
|
|
} |
1097 |
|
|
|
1098 |
|
|
void |
1099 |
pcg |
1.10 |
vpn::dnsv4_client (dns_packet &pkt) |
1100 |
pcg |
1.4 |
{ |
1101 |
pcg |
1.10 |
u16 flags = ntohs (pkt.flags); |
1102 |
pcg |
1.4 |
int offs = 6 * 2; // skip header |
1103 |
|
|
|
1104 |
pcg |
1.10 |
pkt.qdcount = ntohs (pkt.qdcount); |
1105 |
|
|
pkt.ancount = ntohs (pkt.ancount); |
1106 |
pcg |
1.4 |
|
1107 |
pcg |
1.5 |
// go through our request list and find the corresponding request |
1108 |
pcg |
1.10 |
for (vector<dns_snd *>::iterator i = dns_sndpq.begin (); |
1109 |
pcg |
1.4 |
i != dns_sndpq.end (); |
1110 |
|
|
++i) |
1111 |
pcg |
1.10 |
if ((*i)->pkt->id == pkt.id) |
1112 |
pcg |
1.4 |
{ |
1113 |
pcg |
1.9 |
dns_connection *dns = (*i)->dns; |
1114 |
pcg |
1.12 |
connection *c = dns->c; |
1115 |
pcg |
1.5 |
int seqno = (*i)->seqno; |
1116 |
|
|
u8 data[MAXSIZE], *datap = data; |
1117 |
pcg |
1.41 |
//printf ("rcv pkt %x\n", seqno);//D |
1118 |
pcg |
1.5 |
|
1119 |
root |
1.52 |
if ((*i)->retry) |
1120 |
pcg |
1.10 |
{ |
1121 |
pcg |
1.17 |
dns->send_interval *= 1.01; |
1122 |
pcg |
1.12 |
if (dns->send_interval > MAX_SEND_INTERVAL) |
1123 |
pcg |
1.10 |
dns->send_interval = MAX_SEND_INTERVAL; |
1124 |
|
|
} |
1125 |
|
|
else |
1126 |
|
|
{ |
1127 |
pcg |
1.26 |
#if 0 |
1128 |
pcg |
1.17 |
dns->send_interval *= 0.999; |
1129 |
pcg |
1.12 |
#endif |
1130 |
pcg |
1.10 |
// the latency surely puts an upper bound on |
1131 |
|
|
// the minimum send interval |
1132 |
pcg |
1.43 |
double latency = ev_now () - (*i)->sent; |
1133 |
pcg |
1.12 |
|
1134 |
pcg |
1.25 |
if (latency < dns->min_latency) |
1135 |
|
|
dns->min_latency = latency; |
1136 |
|
|
|
1137 |
pcg |
1.37 |
if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
1138 |
|
|
dns->send_interval = dns->min_latency * conf.dns_overlap_factor; |
1139 |
pcg |
1.27 |
|
1140 |
pcg |
1.37 |
if (dns->send_interval < conf.dns_send_interval) |
1141 |
|
|
dns->send_interval = conf.dns_send_interval; |
1142 |
pcg |
1.10 |
} |
1143 |
|
|
|
1144 |
pcg |
1.4 |
delete *i; |
1145 |
|
|
dns_sndpq.erase (i); |
1146 |
|
|
|
1147 |
pcg |
1.10 |
if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK)) |
1148 |
pcg |
1.4 |
{ |
1149 |
|
|
char qname[MAXSIZE]; |
1150 |
|
|
|
1151 |
pcg |
1.10 |
while (pkt.qdcount-- && offs < MAXSIZE - 4) |
1152 |
pcg |
1.4 |
{ |
1153 |
pcg |
1.10 |
int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); |
1154 |
pcg |
1.4 |
offs += 4; // skip qtype, qclass |
1155 |
|
|
} |
1156 |
|
|
|
1157 |
pcg |
1.10 |
while (pkt.ancount-- && offs < MAXSIZE - 10 && datap) |
1158 |
pcg |
1.4 |
{ |
1159 |
pcg |
1.10 |
int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); |
1160 |
|
|
|
1161 |
|
|
u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; |
1162 |
|
|
u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; |
1163 |
|
|
u32 ttl = pkt [offs++] << 24; |
1164 |
|
|
ttl |= pkt [offs++] << 16; |
1165 |
|
|
ttl |= pkt [offs++] << 8; |
1166 |
|
|
ttl |= pkt [offs++]; |
1167 |
|
|
u16 rdlen = pkt [offs++] << 8; rdlen |= pkt [offs++]; |
1168 |
pcg |
1.8 |
|
1169 |
root |
1.51 |
if (qtype == RR_TYPE_NULL || qtype == RR_TYPE_TXT || qtype == dns->cfg.rrtype) |
1170 |
pcg |
1.10 |
{ |
1171 |
|
|
if (rdlen <= MAXSIZE - offs) |
1172 |
|
|
{ |
1173 |
|
|
// decode bytes, finally |
1174 |
|
|
|
1175 |
|
|
while (rdlen) |
1176 |
|
|
{ |
1177 |
|
|
int txtlen = pkt [offs++]; |
1178 |
pcg |
1.4 |
|
1179 |
pcg |
1.10 |
assert (txtlen + offs < MAXSIZE - 1); |
1180 |
pcg |
1.4 |
|
1181 |
pcg |
1.10 |
memcpy (datap, pkt.at (offs), txtlen); |
1182 |
|
|
datap += txtlen; offs += txtlen; |
1183 |
|
|
|
1184 |
|
|
rdlen -= txtlen + 1; |
1185 |
|
|
} |
1186 |
|
|
} |
1187 |
|
|
} |
1188 |
|
|
else if (qtype == RR_TYPE_A) |
1189 |
pcg |
1.5 |
{ |
1190 |
pcg |
1.10 |
u8 ip [4]; |
1191 |
pcg |
1.5 |
|
1192 |
pcg |
1.10 |
ip [0] = pkt [offs++]; |
1193 |
|
|
ip [1] = pkt [offs++]; |
1194 |
|
|
ip [2] = pkt [offs++]; |
1195 |
|
|
ip [3] = pkt [offs++]; |
1196 |
|
|
|
1197 |
|
|
if (ip [0] == CMD_IP_1 |
1198 |
|
|
&& ip [1] == CMD_IP_2 |
1199 |
|
|
&& ip [2] == CMD_IP_3) |
1200 |
pcg |
1.5 |
{ |
1201 |
pcg |
1.17 |
slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]); |
1202 |
pcg |
1.5 |
|
1203 |
pcg |
1.10 |
if (ip [3] == CMD_IP_RST) |
1204 |
|
|
{ |
1205 |
root |
1.51 |
slog (L_DEBUG, _("DNS: got tunnel RST request.")); |
1206 |
pcg |
1.10 |
|
1207 |
root |
1.51 |
dns->reset (); |
1208 |
|
|
return; |
1209 |
pcg |
1.10 |
} |
1210 |
|
|
else if (ip [3] == CMD_IP_SYN) |
1211 |
pcg |
1.12 |
{ |
1212 |
pcg |
1.17 |
slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us.")); |
1213 |
pcg |
1.12 |
dns->established = true; |
1214 |
|
|
} |
1215 |
root |
1.51 |
else if (ip [3] == CMD_IP_CSE) |
1216 |
|
|
{ |
1217 |
|
|
if (conf.dns_case_preserving) |
1218 |
|
|
{ |
1219 |
|
|
slog (L_INFO, _("DNS: got tunnel CSE reply, globally downgrading to case-insensitive protocol.")); |
1220 |
|
|
conf.dns_case_preserving = false; |
1221 |
|
|
dns->reset (); |
1222 |
|
|
return; |
1223 |
|
|
} |
1224 |
|
|
else |
1225 |
|
|
{ |
1226 |
|
|
slog (L_DEBUG, _("DNS: got tunnel CSE reply, server likes us.")); |
1227 |
|
|
dns->established = true; |
1228 |
|
|
} |
1229 |
|
|
} |
1230 |
pcg |
1.12 |
else if (ip [3] == CMD_IP_REJ) |
1231 |
root |
1.51 |
{ |
1232 |
|
|
slog (L_ERR, _("DNS: got tunnel REJ reply, server does not like us.")); |
1233 |
|
|
dns->tw.start (60.); |
1234 |
|
|
} |
1235 |
pcg |
1.10 |
else |
1236 |
root |
1.51 |
{ |
1237 |
|
|
slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]); |
1238 |
|
|
dns->tw.start (60.); |
1239 |
|
|
} |
1240 |
pcg |
1.10 |
} |
1241 |
|
|
else |
1242 |
pcg |
1.17 |
slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"), |
1243 |
pcg |
1.10 |
ip [0], ip [1], ip [2], ip [3]); |
1244 |
pcg |
1.5 |
|
1245 |
pcg |
1.10 |
return; |
1246 |
pcg |
1.9 |
} |
1247 |
pcg |
1.4 |
|
1248 |
pcg |
1.9 |
int client, rseqno; |
1249 |
|
|
decode_header (qname, client, rseqno); |
1250 |
|
|
|
1251 |
|
|
if (client != THISNODE->id) |
1252 |
|
|
{ |
1253 |
pcg |
1.17 |
slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring")); |
1254 |
pcg |
1.9 |
datap = 0; |
1255 |
|
|
} |
1256 |
|
|
else if (rseqno != seqno) |
1257 |
|
|
{ |
1258 |
pcg |
1.17 |
slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?")); |
1259 |
pcg |
1.9 |
datap = 0; |
1260 |
pcg |
1.4 |
} |
1261 |
|
|
} |
1262 |
|
|
} |
1263 |
|
|
|
1264 |
pcg |
1.6 |
// todo: pkt now used |
1265 |
pcg |
1.9 |
if (datap) |
1266 |
|
|
dns->receive_rep (new dns_rcv (seqno, data, datap - data)); |
1267 |
pcg |
1.5 |
|
1268 |
pcg |
1.4 |
break; |
1269 |
|
|
} |
1270 |
|
|
} |
1271 |
|
|
|
1272 |
|
|
void |
1273 |
pcg |
1.42 |
vpn::dnsv4_ev (ev::io &w, int revents) |
1274 |
pcg |
1.4 |
{ |
1275 |
pcg |
1.42 |
if (revents & EV_READ) |
1276 |
pcg |
1.4 |
{ |
1277 |
|
|
dns_packet *pkt = new dns_packet; |
1278 |
|
|
struct sockaddr_in sa; |
1279 |
|
|
socklen_t sa_len = sizeof (sa); |
1280 |
|
|
|
1281 |
pcg |
1.10 |
pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); |
1282 |
pcg |
1.4 |
|
1283 |
|
|
if (pkt->len > 0) |
1284 |
pcg |
1.5 |
{ |
1285 |
pcg |
1.24 |
if (ntohs (pkt->flags) & FLAG_RESPONSE) |
1286 |
|
|
dnsv4_client (*pkt); |
1287 |
|
|
else |
1288 |
pcg |
1.5 |
{ |
1289 |
pcg |
1.10 |
dnsv4_server (*pkt); |
1290 |
|
|
sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); |
1291 |
pcg |
1.5 |
} |
1292 |
pcg |
1.10 |
|
1293 |
|
|
delete pkt; |
1294 |
pcg |
1.5 |
} |
1295 |
pcg |
1.1 |
} |
1296 |
|
|
} |
1297 |
|
|
|
1298 |
|
|
bool |
1299 |
pcg |
1.18 |
vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
1300 |
pcg |
1.3 |
{ |
1301 |
pcg |
1.33 |
int client = ntohl (si.host); |
1302 |
pcg |
1.18 |
|
1303 |
|
|
assert (0 < client && client <= conns.size ()); |
1304 |
|
|
|
1305 |
|
|
connection *c = conns [client - 1]; |
1306 |
|
|
|
1307 |
|
|
if (!c->dns) |
1308 |
|
|
c->dns = new dns_connection (c); |
1309 |
pcg |
1.4 |
|
1310 |
pcg |
1.31 |
if (c->dns->snddq.put (pkt)) |
1311 |
root |
1.52 |
{ |
1312 |
|
|
min_it (c->dns->poll_interval, 0.25); |
1313 |
|
|
c->dns->tw (); |
1314 |
|
|
} |
1315 |
pcg |
1.3 |
|
1316 |
pcg |
1.31 |
// always return true even if the buffer overflows |
1317 |
pcg |
1.3 |
return true; |
1318 |
|
|
} |
1319 |
|
|
|
1320 |
|
|
void |
1321 |
pcg |
1.42 |
dns_connection::time_cb (ev::timer &w, int revents) |
1322 |
pcg |
1.1 |
{ |
1323 |
pcg |
1.10 |
// servers have to be polled |
1324 |
|
|
if (THISNODE->dns_port) |
1325 |
|
|
return; |
1326 |
|
|
|
1327 |
pcg |
1.3 |
// check for timeouts and (re)transmit |
1328 |
root |
1.52 |
tstamp next = 86400 * 365; |
1329 |
pcg |
1.10 |
dns_snd *send = 0; |
1330 |
pcg |
1.3 |
|
1331 |
pcg |
1.10 |
for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1332 |
pcg |
1.4 |
i != vpn->dns_sndpq.end (); |
1333 |
pcg |
1.3 |
++i) |
1334 |
|
|
{ |
1335 |
pcg |
1.10 |
dns_snd *r = *i; |
1336 |
pcg |
1.3 |
|
1337 |
pcg |
1.43 |
if (r->timeout <= ev_now ()) |
1338 |
pcg |
1.3 |
{ |
1339 |
pcg |
1.4 |
if (!send) |
1340 |
|
|
{ |
1341 |
|
|
send = r; |
1342 |
|
|
|
1343 |
|
|
r->retry++; |
1344 |
root |
1.52 |
r->timeout = ev_now () + r->retry * min_latency * conf.dns_timeout_factor; |
1345 |
pcg |
1.43 |
//printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D |
1346 |
pcg |
1.17 |
|
1347 |
|
|
// the following code changes the query section a bit, forcing |
1348 |
|
|
// the forwarder to generate a new request |
1349 |
|
|
if (r->stdhdr) |
1350 |
pcg |
1.41 |
encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); |
1351 |
pcg |
1.4 |
} |
1352 |
pcg |
1.3 |
} |
1353 |
pcg |
1.11 |
else |
1354 |
root |
1.52 |
min_it (next, r->timeout - ev_now ()); |
1355 |
pcg |
1.3 |
} |
1356 |
|
|
|
1357 |
pcg |
1.28 |
if (!send) |
1358 |
pcg |
1.5 |
{ |
1359 |
pcg |
1.29 |
// generate a new packet, if wise |
1360 |
|
|
|
1361 |
|
|
if (!established) |
1362 |
pcg |
1.10 |
{ |
1363 |
pcg |
1.29 |
if (vpn->dns_sndpq.empty ()) |
1364 |
pcg |
1.10 |
{ |
1365 |
pcg |
1.29 |
send = new dns_snd (this); |
1366 |
pcg |
1.10 |
|
1367 |
pcg |
1.29 |
cfg.reset (THISNODE->id); |
1368 |
root |
1.51 |
set_cfg (); |
1369 |
pcg |
1.29 |
send->gen_syn_req (); |
1370 |
pcg |
1.10 |
} |
1371 |
pcg |
1.29 |
} |
1372 |
pcg |
1.37 |
else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
1373 |
pcg |
1.29 |
&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
1374 |
|
|
{ |
1375 |
pcg |
1.43 |
if (last_sent + send_interval <= ev_now ()) |
1376 |
pcg |
1.10 |
{ |
1377 |
pcg |
1.18 |
//printf ("sending data request etc.\n"); //D |
1378 |
root |
1.52 |
if (!snddq.empty ()) |
1379 |
|
|
min_it (next, send_interval); |
1380 |
pcg |
1.17 |
|
1381 |
pcg |
1.10 |
send = new dns_snd (this); |
1382 |
|
|
send->gen_stream_req (sndseq, snddq); |
1383 |
pcg |
1.43 |
send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; |
1384 |
|
|
//printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D |
1385 |
pcg |
1.5 |
|
1386 |
pcg |
1.10 |
sndseq = (sndseq + 1) & SEQNO_MASK; |
1387 |
|
|
} |
1388 |
pcg |
1.29 |
else |
1389 |
root |
1.52 |
min_it (next, last_sent + send_interval - ev_now ()); |
1390 |
pcg |
1.29 |
} |
1391 |
pcg |
1.4 |
|
1392 |
pcg |
1.29 |
if (send) |
1393 |
|
|
vpn->dns_sndpq.push_back (send); |
1394 |
pcg |
1.28 |
} |
1395 |
pcg |
1.4 |
|
1396 |
pcg |
1.28 |
if (send) |
1397 |
|
|
{ |
1398 |
pcg |
1.43 |
last_sent = ev_now (); |
1399 |
pcg |
1.28 |
sendto (vpn->dnsv4_fd, |
1400 |
|
|
send->pkt->at (0), send->pkt->len, 0, |
1401 |
|
|
vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1402 |
pcg |
1.4 |
} |
1403 |
pcg |
1.10 |
|
1404 |
root |
1.52 |
min_it (next, last_sent + max (poll_interval, send_interval) - ev_now ()); |
1405 |
|
|
|
1406 |
pcg |
1.27 |
slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", |
1407 |
pcg |
1.43 |
poll_interval, send_interval, next - ev_now (), |
1408 |
pcg |
1.27 |
vpn->dns_sndpq.size (), snddq.size (), |
1409 |
|
|
rcvpq.size ()); |
1410 |
pcg |
1.11 |
|
1411 |
root |
1.52 |
w.start (next); |
1412 |
pcg |
1.1 |
} |
1413 |
|
|
|
1414 |
|
|
#endif |
1415 |
|
|
|