1 |
adx |
30 |
/* |
2 |
michael |
2916 |
* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd) |
3 |
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* |
4 |
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* Copyright (c) 1997-2014 ircd-hybrid development team |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
8 |
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* the Free Software Foundation; either version 2 of the License, or |
9 |
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* (at your option) any later version. |
10 |
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* |
11 |
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* This program is distributed in the hope that it will be useful, |
12 |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
18 |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
19 |
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* USA |
20 |
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*/ |
21 |
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|
22 |
michael |
3322 |
/*! \file res.c |
23 |
michael |
2916 |
* \brief ircd resolver functions |
24 |
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* \version $Id$ |
25 |
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*/ |
26 |
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27 |
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/* |
28 |
michael |
4312 |
* A rewrite of Darren Reed's original res.c As there is nothing |
29 |
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* left of Darren's original code, this is now licensed by the hybrid group. |
30 |
adx |
30 |
* (Well, some of the function names are the same, and bits of the structs..) |
31 |
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* You can use it where it is useful, free even. Buy us a beer and stuff. |
32 |
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* |
33 |
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* The authors takes no responsibility for any damage or loss |
34 |
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* of property which results from the use of this software. |
35 |
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* |
36 |
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* July 1999 - Rewrote a bunch of stuff here. Change hostent builder code, |
37 |
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* added callbacks and reference counting of returned hostents. |
38 |
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* --Bleep (Thomas Helvey <tomh@inxpress.net>) |
39 |
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* |
40 |
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* This was all needlessly complicated for irc. Simplified. No more hostent |
41 |
michael |
4312 |
* All we really care about is the IP -> hostname mappings. That's all. |
42 |
adx |
30 |
* |
43 |
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* Apr 28, 2003 --cryogen and Dianora |
44 |
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*/ |
45 |
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46 |
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#include "stdinc.h" |
47 |
michael |
1011 |
#include "list.h" |
48 |
adx |
30 |
#include "client.h" |
49 |
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#include "event.h" |
50 |
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#include "irc_string.h" |
51 |
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#include "ircd.h" |
52 |
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#include "numeric.h" |
53 |
michael |
982 |
#include "rng_mt.h" |
54 |
adx |
30 |
#include "fdlist.h" |
55 |
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#include "s_bsd.h" |
56 |
michael |
1309 |
#include "log.h" |
57 |
michael |
3347 |
#include "misc.h" |
58 |
adx |
30 |
#include "send.h" |
59 |
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#include "memory.h" |
60 |
michael |
1654 |
#include "mempool.h" |
61 |
michael |
3322 |
#include "res.h" |
62 |
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#include "reslib.h" |
63 |
adx |
30 |
|
64 |
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#if (CHAR_BIT != 8) |
65 |
michael |
2916 |
#error this code needs to be able to address individual octets |
66 |
adx |
30 |
#endif |
67 |
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|
68 |
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static PF res_readreply; |
69 |
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|
70 |
michael |
4312 |
#define MAXPACKET 1024 /**< rfc says 512 but we expand names so ... */ |
71 |
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#define AR_TTL 600 /**< TTL in seconds for dns cache entries */ |
72 |
adx |
30 |
|
73 |
michael |
4312 |
/* |
74 |
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* RFC 1104/1105 wasn't very helpful about what these fields |
75 |
adx |
30 |
* should be named, so for now, we'll just name them this way. |
76 |
michael |
4312 |
* We probably should look at what named calls them or something. |
77 |
adx |
30 |
*/ |
78 |
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#define TYPE_SIZE (size_t)2 |
79 |
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#define CLASS_SIZE (size_t)2 |
80 |
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#define TTL_SIZE (size_t)4 |
81 |
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#define RDLENGTH_SIZE (size_t)2 |
82 |
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#define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE) |
83 |
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|
84 |
michael |
2916 |
typedef enum |
85 |
adx |
30 |
{ |
86 |
michael |
4312 |
REQ_IDLE, /**< We're doing not much at all */ |
87 |
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REQ_PTR, /**< Looking up a PTR */ |
88 |
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REQ_A, /**< Looking up an A, possibly because AAAA failed */ |
89 |
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REQ_AAAA, /**< Looking up an AAAA */ |
90 |
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REQ_CNAME /**< We got a CNAME in response, we better get a real answer next */ |
91 |
adx |
30 |
} request_state; |
92 |
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|
93 |
michael |
2916 |
struct reslist |
94 |
adx |
30 |
{ |
95 |
michael |
4422 |
dlink_node node; /**< Doubly linked list node. */ |
96 |
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int id; /**< Request ID (from request header). */ |
97 |
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int sent; /**< Number of requests sent */ |
98 |
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request_state state; /**< State the resolver machine is in */ |
99 |
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char type; /**< Current request type. */ |
100 |
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char retries; /**< Retry counter */ |
101 |
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unsigned int sends; /**< Number of sends (>1 means resent). */ |
102 |
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char resend; /**< Send flag; 0 == don't resend. */ |
103 |
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time_t sentat; /**< Timestamp we last sent this request. */ |
104 |
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time_t timeout; /**< When this request times out. */ |
105 |
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struct irc_ssaddr addr; /**< Address for this request. */ |
106 |
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char name[RFC1035_MAX_DOMAIN_LENGTH + 1]; /**< Hostname for this request. */ |
107 |
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size_t namelength; /**< Actual hostname length. */ |
108 |
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dns_callback_fnc callback; /**< Callback function on completion. */ |
109 |
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void *callback_ctx; /**< Context pointer for callback. */ |
110 |
adx |
30 |
}; |
111 |
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112 |
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static fde_t ResolverFileDescriptor; |
113 |
michael |
3235 |
static dlink_list request_list; |
114 |
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static mp_pool_t *dns_pool; |
115 |
adx |
30 |
|
116 |
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117 |
michael |
4312 |
/* |
118 |
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* rem_request - remove a request from the list. |
119 |
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* This must also free any memory that has been allocated for |
120 |
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* temporary storage of DNS results. |
121 |
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*/ |
122 |
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static void |
123 |
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rem_request(struct reslist *request) |
124 |
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{ |
125 |
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dlinkDelete(&request->node, &request_list); |
126 |
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mp_pool_release(request); |
127 |
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} |
128 |
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|
129 |
adx |
30 |
/* |
130 |
michael |
4312 |
* make_request - Create a DNS request record for the server. |
131 |
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*/ |
132 |
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static struct reslist * |
133 |
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make_request(dns_callback_fnc callback, void *ctx) |
134 |
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{ |
135 |
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struct reslist *request = mp_pool_get(dns_pool); |
136 |
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137 |
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request->sentat = CurrentTime; |
138 |
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request->retries = 2; |
139 |
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request->resend = 1; |
140 |
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request->timeout = 4; /* Start at 4 and exponential inc. */ |
141 |
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request->state = REQ_IDLE; |
142 |
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request->callback = callback; |
143 |
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request->callback_ctx = ctx; |
144 |
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145 |
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dlinkAdd(request, &request->node, &request_list); |
146 |
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return request; |
147 |
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} |
148 |
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149 |
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/* |
150 |
adx |
30 |
* int |
151 |
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* res_ourserver(inp) |
152 |
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* looks up "inp" in irc_nsaddr_list[] |
153 |
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* returns: |
154 |
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* 0 : not found |
155 |
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* >0 : found |
156 |
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* author: |
157 |
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* paul vixie, 29may94 |
158 |
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* revised for ircd, cryogen(stu) may03 |
159 |
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*/ |
160 |
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static int |
161 |
michael |
2916 |
res_ourserver(const struct irc_ssaddr *inp) |
162 |
adx |
30 |
{ |
163 |
michael |
992 |
const struct sockaddr_in6 *v6; |
164 |
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const struct sockaddr_in6 *v6in = (const struct sockaddr_in6 *)inp; |
165 |
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const struct sockaddr_in *v4; |
166 |
michael |
2916 |
const struct sockaddr_in *v4in = (const struct sockaddr_in *)inp; |
167 |
adx |
30 |
|
168 |
michael |
3297 |
for (unsigned int i = 0; i < irc_nscount; ++i) |
169 |
adx |
30 |
{ |
170 |
michael |
3235 |
const struct irc_ssaddr *srv = &irc_nsaddr_list[i]; |
171 |
michael |
992 |
v6 = (const struct sockaddr_in6 *)srv; |
172 |
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v4 = (const struct sockaddr_in *)srv; |
173 |
adx |
30 |
|
174 |
michael |
4312 |
/* |
175 |
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* Could probably just memcmp(srv, inp, srv.ss_len) here |
176 |
adx |
30 |
* but we'll air on the side of caution - stu |
177 |
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*/ |
178 |
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switch (srv->ss.ss_family) |
179 |
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{ |
180 |
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case AF_INET6: |
181 |
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if (srv->ss.ss_family == inp->ss.ss_family) |
182 |
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if (v6->sin6_port == v6in->sin6_port) |
183 |
michael |
1346 |
if (!memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr, |
184 |
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sizeof(struct in6_addr))) |
185 |
michael |
1124 |
return 1; |
186 |
adx |
30 |
break; |
187 |
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case AF_INET: |
188 |
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if (srv->ss.ss_family == inp->ss.ss_family) |
189 |
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if (v4->sin_port == v4in->sin_port) |
190 |
michael |
1346 |
if (v4->sin_addr.s_addr == v4in->sin_addr.s_addr) |
191 |
michael |
1124 |
return 1; |
192 |
adx |
30 |
break; |
193 |
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default: |
194 |
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break; |
195 |
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} |
196 |
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} |
197 |
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198 |
michael |
1124 |
return 0; |
199 |
adx |
30 |
} |
200 |
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|
201 |
|
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/* |
202 |
|
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* start_resolver - do everything we need to read the resolv.conf file |
203 |
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* and initialize the resolver file descriptor if needed |
204 |
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*/ |
205 |
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static void |
206 |
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start_resolver(void) |
207 |
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{ |
208 |
|
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irc_res_init(); |
209 |
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|
210 |
|
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if (!ResolverFileDescriptor.flags.open) |
211 |
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{ |
212 |
|
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if (comm_open(&ResolverFileDescriptor, irc_nsaddr_list[0].ss.ss_family, |
213 |
michael |
4447 |
SOCK_DGRAM, 0, "UDP resolver socket") == -1) |
214 |
adx |
30 |
return; |
215 |
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|
216 |
|
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/* At the moment, the resolver FD data is global .. */ |
217 |
michael |
3298 |
comm_setselect(&ResolverFileDescriptor, COMM_SELECT_READ, res_readreply, NULL, 0); |
218 |
adx |
30 |
} |
219 |
|
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} |
220 |
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221 |
|
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/* |
222 |
|
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* restart_resolver - reread resolv.conf, reopen socket |
223 |
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*/ |
224 |
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void |
225 |
|
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restart_resolver(void) |
226 |
|
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{ |
227 |
|
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fd_close(&ResolverFileDescriptor); |
228 |
|
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start_resolver(); |
229 |
|
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} |
230 |
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|
231 |
|
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/* |
232 |
michael |
2916 |
* delete_resolver_queries - cleanup outstanding queries |
233 |
adx |
30 |
* for which there no longer exist clients or conf lines. |
234 |
|
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*/ |
235 |
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void |
236 |
michael |
992 |
delete_resolver_queries(const void *vptr) |
237 |
adx |
30 |
{ |
238 |
michael |
3235 |
dlink_node *ptr = NULL, *ptr_next = NULL; |
239 |
adx |
30 |
|
240 |
michael |
3235 |
DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head) |
241 |
adx |
30 |
{ |
242 |
michael |
997 |
struct reslist *request = ptr->data; |
243 |
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|
244 |
|
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if (request->callback_ctx == vptr) |
245 |
|
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rem_request(request); |
246 |
adx |
30 |
} |
247 |
|
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} |
248 |
|
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|
249 |
|
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/* |
250 |
|
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* send_res_msg - sends msg to all nameservers found in the "_res" structure. |
251 |
|
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* This should reflect /etc/resolv.conf. We will get responses |
252 |
|
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* which arent needed but is easier than checking to see if nameserver |
253 |
michael |
4299 |
* isn't present. Returns number of messages successfully sent to |
254 |
adx |
30 |
* nameservers or -1 if no successful sends. |
255 |
|
|
*/ |
256 |
|
|
static int |
257 |
michael |
3297 |
send_res_msg(const char *msg, int len, unsigned int rcount) |
258 |
adx |
30 |
{ |
259 |
|
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int sent = 0; |
260 |
michael |
3297 |
unsigned int max_queries = IRCD_MIN(irc_nscount, rcount); |
261 |
adx |
30 |
|
262 |
|
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/* RES_PRIMARY option is not implemented |
263 |
|
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* if (res.options & RES_PRIMARY || 0 == max_queries) |
264 |
|
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*/ |
265 |
|
|
if (max_queries == 0) |
266 |
|
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max_queries = 1; |
267 |
|
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|
268 |
michael |
3297 |
for (unsigned int i = 0; i < max_queries; ++i) |
269 |
adx |
30 |
{ |
270 |
michael |
2916 |
if (sendto(ResolverFileDescriptor.fd, msg, len, 0, |
271 |
|
|
(struct sockaddr*)&(irc_nsaddr_list[i]), |
272 |
|
|
irc_nsaddr_list[i].ss_len) == len) |
273 |
adx |
30 |
++sent; |
274 |
|
|
} |
275 |
|
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|
276 |
michael |
1124 |
return sent; |
277 |
adx |
30 |
} |
278 |
|
|
|
279 |
|
|
/* |
280 |
|
|
* find_id - find a dns request id (id is determined by dn_mkquery) |
281 |
|
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*/ |
282 |
|
|
static struct reslist * |
283 |
|
|
find_id(int id) |
284 |
|
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{ |
285 |
michael |
1124 |
dlink_node *ptr = NULL; |
286 |
adx |
30 |
|
287 |
|
|
DLINK_FOREACH(ptr, request_list.head) |
288 |
|
|
{ |
289 |
michael |
1124 |
struct reslist *request = ptr->data; |
290 |
adx |
30 |
|
291 |
|
|
if (request->id == id) |
292 |
michael |
1124 |
return request; |
293 |
adx |
30 |
} |
294 |
|
|
|
295 |
michael |
1124 |
return NULL; |
296 |
adx |
30 |
} |
297 |
|
|
|
298 |
michael |
2916 |
/* |
299 |
michael |
4312 |
* query_name - generate a query based on class, type and name. |
300 |
adx |
30 |
*/ |
301 |
michael |
4312 |
static void |
302 |
|
|
query_name(const char *name, int query_class, int type, |
303 |
|
|
struct reslist *request) |
304 |
adx |
30 |
{ |
305 |
michael |
4312 |
char buf[MAXPACKET]; |
306 |
|
|
int request_len = 0; |
307 |
adx |
30 |
|
308 |
michael |
4312 |
memset(buf, 0, sizeof(buf)); |
309 |
adx |
30 |
|
310 |
michael |
4312 |
if ((request_len = irc_res_mkquery(name, query_class, type, |
311 |
|
|
(unsigned char *)buf, sizeof(buf))) > 0) |
312 |
|
|
{ |
313 |
|
|
HEADER *header = (HEADER *)buf; |
314 |
|
|
|
315 |
|
|
/* |
316 |
|
|
* Generate an unique id. |
317 |
|
|
* NOTE: we don't have to worry about converting this to and from |
318 |
|
|
* network byte order, the nameserver does not interpret this value |
319 |
|
|
* and returns it unchanged. |
320 |
|
|
*/ |
321 |
|
|
do |
322 |
|
|
header->id = (header->id + genrand_int32()) & 0xFFFF; |
323 |
|
|
while (find_id(header->id)); |
324 |
|
|
|
325 |
|
|
request->id = header->id; |
326 |
|
|
++request->sends; |
327 |
|
|
|
328 |
|
|
request->sent += send_res_msg(buf, request_len, request->sends); |
329 |
|
|
} |
330 |
adx |
30 |
} |
331 |
|
|
|
332 |
|
|
/* |
333 |
|
|
* do_query_name - nameserver lookup name |
334 |
|
|
*/ |
335 |
|
|
static void |
336 |
michael |
992 |
do_query_name(dns_callback_fnc callback, void *ctx, const char *name, |
337 |
adx |
30 |
struct reslist *request, int type) |
338 |
|
|
{ |
339 |
michael |
4409 |
char host_name[RFC1035_MAX_DOMAIN_LENGTH + 1]; |
340 |
adx |
30 |
|
341 |
michael |
998 |
strlcpy(host_name, name, sizeof(host_name)); |
342 |
adx |
30 |
|
343 |
|
|
if (request == NULL) |
344 |
|
|
{ |
345 |
michael |
4409 |
request = make_request(callback, ctx); |
346 |
|
|
request->type = type; |
347 |
|
|
request->namelength = strlcpy(request->name, host_name, sizeof(request->name)); |
348 |
michael |
4414 |
|
349 |
michael |
984 |
if (type != T_A) |
350 |
|
|
request->state = REQ_AAAA; |
351 |
adx |
30 |
else |
352 |
michael |
4414 |
request->state = REQ_A; |
353 |
adx |
30 |
} |
354 |
|
|
|
355 |
|
|
request->type = type; |
356 |
|
|
query_name(host_name, C_IN, type, request); |
357 |
|
|
} |
358 |
|
|
|
359 |
|
|
/* |
360 |
|
|
* do_query_number - Use this to do reverse IP# lookups. |
361 |
|
|
*/ |
362 |
|
|
static void |
363 |
michael |
992 |
do_query_number(dns_callback_fnc callback, void *ctx, |
364 |
|
|
const struct irc_ssaddr *addr, |
365 |
adx |
30 |
struct reslist *request) |
366 |
|
|
{ |
367 |
michael |
3298 |
char ipbuf[128] = ""; |
368 |
michael |
985 |
|
369 |
adx |
30 |
if (addr->ss.ss_family == AF_INET) |
370 |
|
|
{ |
371 |
michael |
992 |
const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr; |
372 |
michael |
3298 |
const unsigned char *cp = (const unsigned char *)&v4->sin_addr.s_addr; |
373 |
adx |
30 |
|
374 |
michael |
1124 |
snprintf(ipbuf, sizeof(ipbuf), "%u.%u.%u.%u.in-addr.arpa.", |
375 |
|
|
(unsigned int)(cp[3]), (unsigned int)(cp[2]), |
376 |
|
|
(unsigned int)(cp[1]), (unsigned int)(cp[0])); |
377 |
adx |
30 |
} |
378 |
|
|
else if (addr->ss.ss_family == AF_INET6) |
379 |
|
|
{ |
380 |
michael |
992 |
const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr; |
381 |
michael |
3298 |
const unsigned char *cp = (const unsigned char *)&v6->sin6_addr.s6_addr; |
382 |
adx |
30 |
|
383 |
michael |
1124 |
snprintf(ipbuf, sizeof(ipbuf), |
384 |
|
|
"%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x." |
385 |
|
|
"%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa.", |
386 |
|
|
(unsigned int)(cp[15] & 0xf), (unsigned int)(cp[15] >> 4), |
387 |
|
|
(unsigned int)(cp[14] & 0xf), (unsigned int)(cp[14] >> 4), |
388 |
|
|
(unsigned int)(cp[13] & 0xf), (unsigned int)(cp[13] >> 4), |
389 |
|
|
(unsigned int)(cp[12] & 0xf), (unsigned int)(cp[12] >> 4), |
390 |
|
|
(unsigned int)(cp[11] & 0xf), (unsigned int)(cp[11] >> 4), |
391 |
|
|
(unsigned int)(cp[10] & 0xf), (unsigned int)(cp[10] >> 4), |
392 |
|
|
(unsigned int)(cp[9] & 0xf), (unsigned int)(cp[9] >> 4), |
393 |
|
|
(unsigned int)(cp[8] & 0xf), (unsigned int)(cp[8] >> 4), |
394 |
|
|
(unsigned int)(cp[7] & 0xf), (unsigned int)(cp[7] >> 4), |
395 |
|
|
(unsigned int)(cp[6] & 0xf), (unsigned int)(cp[6] >> 4), |
396 |
|
|
(unsigned int)(cp[5] & 0xf), (unsigned int)(cp[5] >> 4), |
397 |
|
|
(unsigned int)(cp[4] & 0xf), (unsigned int)(cp[4] >> 4), |
398 |
|
|
(unsigned int)(cp[3] & 0xf), (unsigned int)(cp[3] >> 4), |
399 |
|
|
(unsigned int)(cp[2] & 0xf), (unsigned int)(cp[2] >> 4), |
400 |
|
|
(unsigned int)(cp[1] & 0xf), (unsigned int)(cp[1] >> 4), |
401 |
|
|
(unsigned int)(cp[0] & 0xf), (unsigned int)(cp[0] >> 4)); |
402 |
adx |
30 |
} |
403 |
michael |
4414 |
|
404 |
adx |
30 |
if (request == NULL) |
405 |
|
|
{ |
406 |
michael |
992 |
request = make_request(callback, ctx); |
407 |
adx |
30 |
request->type = T_PTR; |
408 |
|
|
memcpy(&request->addr, addr, sizeof(struct irc_ssaddr)); |
409 |
|
|
} |
410 |
|
|
|
411 |
|
|
query_name(ipbuf, C_IN, T_PTR, request); |
412 |
|
|
} |
413 |
|
|
|
414 |
|
|
/* |
415 |
michael |
4312 |
* gethost_byname_type - get host address from name |
416 |
|
|
* |
417 |
adx |
30 |
*/ |
418 |
michael |
4312 |
void |
419 |
|
|
gethost_byname_type(dns_callback_fnc callback, void *ctx, const char *name, int type) |
420 |
adx |
30 |
{ |
421 |
michael |
4312 |
assert(name); |
422 |
|
|
do_query_name(callback, ctx, name, NULL, type); |
423 |
|
|
} |
424 |
adx |
30 |
|
425 |
michael |
4312 |
/* |
426 |
|
|
* gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported |
427 |
|
|
*/ |
428 |
|
|
void |
429 |
|
|
gethost_byname(dns_callback_fnc callback, void *ctx, const char *name) |
430 |
|
|
{ |
431 |
|
|
gethost_byname_type(callback, ctx, name, T_AAAA); |
432 |
|
|
} |
433 |
adx |
30 |
|
434 |
michael |
4312 |
/* |
435 |
|
|
* gethost_byaddr - get host name from address |
436 |
|
|
*/ |
437 |
|
|
void |
438 |
|
|
gethost_byaddr(dns_callback_fnc callback, void *ctx, const struct irc_ssaddr *addr) |
439 |
|
|
{ |
440 |
|
|
do_query_number(callback, ctx, addr, NULL); |
441 |
adx |
30 |
} |
442 |
|
|
|
443 |
|
|
static void |
444 |
|
|
resend_query(struct reslist *request) |
445 |
|
|
{ |
446 |
|
|
if (request->resend == 0) |
447 |
|
|
return; |
448 |
|
|
|
449 |
michael |
982 |
switch (request->type) |
450 |
adx |
30 |
{ |
451 |
|
|
case T_PTR: |
452 |
michael |
992 |
do_query_number(NULL, NULL, &request->addr, request); |
453 |
adx |
30 |
break; |
454 |
|
|
case T_A: |
455 |
michael |
992 |
do_query_name(NULL, NULL, request->name, request, request->type); |
456 |
adx |
30 |
break; |
457 |
michael |
4299 |
case T_AAAA: /* Didn't work, try A */ |
458 |
adx |
30 |
if (request->state == REQ_AAAA) |
459 |
michael |
992 |
do_query_name(NULL, NULL, request->name, request, T_A); |
460 |
adx |
30 |
default: |
461 |
|
|
break; |
462 |
|
|
} |
463 |
|
|
} |
464 |
|
|
|
465 |
|
|
/* |
466 |
|
|
* proc_answer - process name server reply |
467 |
|
|
*/ |
468 |
|
|
static int |
469 |
michael |
1124 |
proc_answer(struct reslist *request, HEADER *header, char *buf, char *eob) |
470 |
adx |
30 |
{ |
471 |
michael |
4409 |
char hostbuf[RFC1035_MAX_DOMAIN_LENGTH + 100]; /* working buffer */ |
472 |
adx |
30 |
unsigned char *current; /* current position in buf */ |
473 |
|
|
int type; /* answer type */ |
474 |
|
|
int n; /* temp count */ |
475 |
|
|
int rd_length; |
476 |
|
|
struct sockaddr_in *v4; /* conversion */ |
477 |
|
|
struct sockaddr_in6 *v6; |
478 |
michael |
4414 |
|
479 |
adx |
30 |
current = (unsigned char *)buf + sizeof(HEADER); |
480 |
|
|
|
481 |
|
|
for (; header->qdcount > 0; --header->qdcount) |
482 |
|
|
{ |
483 |
|
|
if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0) |
484 |
|
|
break; |
485 |
|
|
|
486 |
michael |
1124 |
current += (size_t)n + QFIXEDSZ; |
487 |
adx |
30 |
} |
488 |
|
|
|
489 |
|
|
/* |
490 |
michael |
4299 |
* Process each answer sent to us blech. |
491 |
adx |
30 |
*/ |
492 |
|
|
while (header->ancount > 0 && (char *)current < eob) |
493 |
|
|
{ |
494 |
|
|
header->ancount--; |
495 |
|
|
|
496 |
|
|
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, |
497 |
|
|
hostbuf, sizeof(hostbuf)); |
498 |
|
|
|
499 |
michael |
4299 |
if (n < 0 /* Broken message */ || n == 0 /* No more answers left */) |
500 |
michael |
1124 |
return 0; |
501 |
adx |
30 |
|
502 |
michael |
4409 |
hostbuf[RFC1035_MAX_DOMAIN_LENGTH] = '\0'; |
503 |
adx |
30 |
|
504 |
michael |
4299 |
/* |
505 |
|
|
* With Address arithmetic you have to be very anal |
506 |
adx |
30 |
* this code was not working on alpha due to that |
507 |
|
|
* (spotted by rodder/jailbird/dianora) |
508 |
|
|
*/ |
509 |
michael |
3298 |
current += (size_t)n; |
510 |
adx |
30 |
|
511 |
|
|
if (!(((char *)current + ANSWER_FIXED_SIZE) < eob)) |
512 |
|
|
break; |
513 |
|
|
|
514 |
|
|
type = irc_ns_get16(current); |
515 |
|
|
current += TYPE_SIZE; |
516 |
|
|
current += CLASS_SIZE; |
517 |
|
|
current += TTL_SIZE; |
518 |
|
|
rd_length = irc_ns_get16(current); |
519 |
|
|
current += RDLENGTH_SIZE; |
520 |
|
|
|
521 |
michael |
2916 |
/* |
522 |
|
|
* Wait to set request->type until we verify this structure |
523 |
adx |
30 |
*/ |
524 |
|
|
switch (type) |
525 |
|
|
{ |
526 |
|
|
case T_A: |
527 |
|
|
if (request->type != T_A) |
528 |
michael |
1124 |
return 0; |
529 |
adx |
30 |
|
530 |
|
|
/* |
531 |
michael |
3298 |
* Check for invalid rd_length or too many addresses |
532 |
adx |
30 |
*/ |
533 |
|
|
if (rd_length != sizeof(struct in_addr)) |
534 |
michael |
1124 |
return 0; |
535 |
|
|
|
536 |
adx |
30 |
v4 = (struct sockaddr_in *)&request->addr; |
537 |
|
|
request->addr.ss_len = sizeof(struct sockaddr_in); |
538 |
|
|
v4->sin_family = AF_INET; |
539 |
|
|
memcpy(&v4->sin_addr, current, sizeof(struct in_addr)); |
540 |
michael |
1124 |
return 1; |
541 |
adx |
30 |
break; |
542 |
|
|
case T_AAAA: |
543 |
|
|
if (request->type != T_AAAA) |
544 |
michael |
1124 |
return 0; |
545 |
|
|
|
546 |
adx |
30 |
if (rd_length != sizeof(struct in6_addr)) |
547 |
michael |
1124 |
return 0; |
548 |
|
|
|
549 |
adx |
30 |
request->addr.ss_len = sizeof(struct sockaddr_in6); |
550 |
|
|
v6 = (struct sockaddr_in6 *)&request->addr; |
551 |
|
|
v6->sin6_family = AF_INET6; |
552 |
|
|
memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr)); |
553 |
michael |
1124 |
return 1; |
554 |
adx |
30 |
break; |
555 |
|
|
case T_PTR: |
556 |
|
|
if (request->type != T_PTR) |
557 |
michael |
1124 |
return 0; |
558 |
|
|
|
559 |
adx |
30 |
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, |
560 |
michael |
3298 |
current, hostbuf, sizeof(hostbuf)); |
561 |
michael |
4299 |
if (n < 0 /* Broken message */ || n == 0 /* No more answers left */) |
562 |
michael |
1124 |
return 0; |
563 |
adx |
30 |
|
564 |
michael |
4409 |
request->namelength = strlcpy(request->name, hostbuf, sizeof(request->name)); |
565 |
michael |
1124 |
return 1; |
566 |
adx |
30 |
break; |
567 |
michael |
4299 |
case T_CNAME: /* First check we already haven't started looking into a cname */ |
568 |
michael |
2916 |
if (request->type != T_PTR) |
569 |
michael |
1124 |
return 0; |
570 |
adx |
30 |
|
571 |
|
|
if (request->state == REQ_CNAME) |
572 |
|
|
{ |
573 |
|
|
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, |
574 |
|
|
current, hostbuf, sizeof(hostbuf)); |
575 |
|
|
|
576 |
|
|
if (n < 0) |
577 |
michael |
1124 |
return 0; |
578 |
|
|
return 1; |
579 |
adx |
30 |
} |
580 |
|
|
|
581 |
|
|
request->state = REQ_CNAME; |
582 |
|
|
current += rd_length; |
583 |
|
|
break; |
584 |
michael |
2916 |
|
585 |
adx |
30 |
default: |
586 |
|
|
/* XXX I'd rather just throw away the entire bogus thing |
587 |
|
|
* but its possible its just a broken nameserver with still |
588 |
|
|
* valid answers. But lets do some rudimentary logging for now... |
589 |
|
|
*/ |
590 |
michael |
1247 |
ilog(LOG_TYPE_IRCD, "irc_res.c bogus type %d", type); |
591 |
adx |
30 |
break; |
592 |
|
|
} |
593 |
|
|
} |
594 |
|
|
|
595 |
michael |
1124 |
return 1; |
596 |
adx |
30 |
} |
597 |
|
|
|
598 |
|
|
/* |
599 |
|
|
* res_readreply - read a dns reply from the nameserver and process it. |
600 |
|
|
*/ |
601 |
|
|
static void |
602 |
|
|
res_readreply(fde_t *fd, void *data) |
603 |
|
|
{ |
604 |
michael |
4239 |
char buf[sizeof(HEADER) + MAXPACKET]; |
605 |
adx |
30 |
HEADER *header; |
606 |
|
|
struct reslist *request = NULL; |
607 |
michael |
4302 |
ssize_t rc = 0; |
608 |
adx |
30 |
socklen_t len = sizeof(struct irc_ssaddr); |
609 |
|
|
struct irc_ssaddr lsin; |
610 |
|
|
|
611 |
michael |
4318 |
while ((rc = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len)) != -1) |
612 |
|
|
{ |
613 |
|
|
if (rc <= (ssize_t)sizeof(HEADER)) |
614 |
|
|
continue; |
615 |
adx |
30 |
|
616 |
michael |
4318 |
/* |
617 |
|
|
* Check against possibly fake replies |
618 |
|
|
*/ |
619 |
|
|
if (!res_ourserver(&lsin)) |
620 |
|
|
continue; |
621 |
michael |
984 |
|
622 |
michael |
4318 |
/* |
623 |
|
|
* Convert DNS reply reader from Network byte order to CPU byte order. |
624 |
|
|
*/ |
625 |
|
|
header = (HEADER *)buf; |
626 |
|
|
header->ancount = ntohs(header->ancount); |
627 |
|
|
header->qdcount = ntohs(header->qdcount); |
628 |
|
|
header->nscount = ntohs(header->nscount); |
629 |
|
|
header->arcount = ntohs(header->arcount); |
630 |
adx |
30 |
|
631 |
michael |
4318 |
/* |
632 |
|
|
* Response for an id which we have already received an answer for |
633 |
|
|
* just ignore this response. |
634 |
|
|
*/ |
635 |
|
|
if ((request = find_id(header->id)) == NULL) |
636 |
|
|
continue; |
637 |
michael |
4238 |
|
638 |
michael |
4318 |
if ((header->rcode != NO_ERRORS) || (header->ancount == 0)) |
639 |
|
|
{ |
640 |
|
|
if (header->rcode == SERVFAIL || header->rcode == NXDOMAIN) |
641 |
|
|
{ |
642 |
|
|
/* |
643 |
|
|
* If a bad error was returned, stop here and don't |
644 |
|
|
* send any more (no retries granted). |
645 |
|
|
*/ |
646 |
michael |
4409 |
(*request->callback)(request->callback_ctx, NULL, NULL, 0); |
647 |
michael |
4318 |
rem_request(request); |
648 |
|
|
} |
649 |
|
|
else |
650 |
|
|
{ |
651 |
|
|
/* |
652 |
|
|
* If we havent already tried this, and we're looking up AAAA, try A now. |
653 |
|
|
*/ |
654 |
|
|
if (request->state == REQ_AAAA && request->type == T_AAAA) |
655 |
|
|
{ |
656 |
|
|
request->timeout += 4; |
657 |
|
|
resend_query(request); |
658 |
|
|
} |
659 |
|
|
} |
660 |
michael |
4414 |
|
661 |
michael |
4318 |
continue; |
662 |
|
|
} |
663 |
adx |
30 |
|
664 |
michael |
4318 |
/* |
665 |
|
|
* If this fails there was an error decoding the received packet. |
666 |
|
|
* We only give it one shot. If it fails, just leave the client |
667 |
|
|
* unresolved. |
668 |
|
|
*/ |
669 |
|
|
if (!proc_answer(request, header, buf, buf + rc)) |
670 |
db |
155 |
{ |
671 |
michael |
4409 |
(*request->callback)(request->callback_ctx, NULL, NULL, 0); |
672 |
michael |
984 |
rem_request(request); |
673 |
michael |
4318 |
continue; |
674 |
michael |
984 |
} |
675 |
michael |
4318 |
|
676 |
|
|
if (request->type == T_PTR) |
677 |
michael |
984 |
{ |
678 |
michael |
4409 |
if (request->namelength == 0) |
679 |
michael |
4318 |
{ |
680 |
|
|
/* |
681 |
|
|
* Got a PTR response with no name, something bogus is happening |
682 |
|
|
* don't bother trying again, the client address doesn't resolve |
683 |
|
|
*/ |
684 |
michael |
4409 |
(*request->callback)(request->callback_ctx, NULL, NULL, 0); |
685 |
michael |
4318 |
rem_request(request); |
686 |
|
|
continue; |
687 |
|
|
} |
688 |
|
|
|
689 |
michael |
2916 |
/* |
690 |
michael |
4318 |
* Lookup the 'authoritative' name that we were given for the ip#. |
691 |
adx |
30 |
*/ |
692 |
michael |
4318 |
if (request->addr.ss.ss_family == AF_INET6) |
693 |
|
|
gethost_byname_type(request->callback, request->callback_ctx, request->name, T_AAAA); |
694 |
|
|
else |
695 |
michael |
4414 |
gethost_byname_type(request->callback, request->callback_ctx, request->name, T_A); |
696 |
michael |
4318 |
rem_request(request); |
697 |
michael |
984 |
} |
698 |
michael |
4318 |
else |
699 |
adx |
30 |
{ |
700 |
|
|
/* |
701 |
michael |
4318 |
* Got a name and address response, client resolved |
702 |
adx |
30 |
*/ |
703 |
michael |
4409 |
(*request->callback)(request->callback_ctx, &request->addr, request->name, request->namelength); |
704 |
adx |
30 |
rem_request(request); |
705 |
|
|
} |
706 |
michael |
4315 |
|
707 |
michael |
4318 |
continue; |
708 |
adx |
30 |
} |
709 |
michael |
4318 |
|
710 |
|
|
comm_setselect(fd, COMM_SELECT_READ, res_readreply, NULL, 0); |
711 |
adx |
30 |
} |
712 |
|
|
|
713 |
|
|
void |
714 |
|
|
report_dns_servers(struct Client *source_p) |
715 |
|
|
{ |
716 |
michael |
3235 |
char ipaddr[HOSTIPLEN + 1] = ""; |
717 |
adx |
30 |
|
718 |
michael |
3297 |
for (unsigned int i = 0; i < irc_nscount; ++i) |
719 |
adx |
30 |
{ |
720 |
michael |
1123 |
getnameinfo((struct sockaddr *)&(irc_nsaddr_list[i]), |
721 |
|
|
irc_nsaddr_list[i].ss_len, ipaddr, |
722 |
|
|
sizeof(ipaddr), NULL, 0, NI_NUMERICHOST); |
723 |
michael |
3109 |
sendto_one_numeric(source_p, &me, RPL_STATSALINE, ipaddr); |
724 |
adx |
30 |
} |
725 |
|
|
} |
726 |
michael |
4312 |
|
727 |
|
|
/* |
728 |
|
|
* timeout_query_list - Remove queries from the list which have been |
729 |
|
|
* there too long without being resolved. |
730 |
|
|
*/ |
731 |
|
|
static time_t |
732 |
|
|
timeout_query_list(void) |
733 |
|
|
{ |
734 |
|
|
dlink_node *ptr = NULL, *ptr_next = NULL; |
735 |
|
|
struct reslist *request = NULL; |
736 |
|
|
time_t next_time = 0; |
737 |
|
|
time_t timeout = 0; |
738 |
|
|
|
739 |
|
|
DLINK_FOREACH_SAFE(ptr, ptr_next, request_list.head) |
740 |
|
|
{ |
741 |
|
|
request = ptr->data; |
742 |
|
|
timeout = request->sentat + request->timeout; |
743 |
|
|
|
744 |
|
|
if (CurrentTime >= timeout) |
745 |
|
|
{ |
746 |
|
|
if (--request->retries <= 0) |
747 |
|
|
{ |
748 |
michael |
4409 |
(*request->callback)(request->callback_ctx, NULL, NULL, 0); |
749 |
michael |
4312 |
rem_request(request); |
750 |
|
|
continue; |
751 |
|
|
} |
752 |
|
|
else |
753 |
|
|
{ |
754 |
|
|
request->sentat = CurrentTime; |
755 |
|
|
request->timeout += request->timeout; |
756 |
|
|
resend_query(request); |
757 |
|
|
} |
758 |
|
|
} |
759 |
|
|
|
760 |
|
|
if (next_time == 0 || timeout < next_time) |
761 |
|
|
next_time = timeout; |
762 |
|
|
} |
763 |
|
|
|
764 |
|
|
return (next_time > CurrentTime) ? next_time : (CurrentTime + AR_TTL); |
765 |
|
|
} |
766 |
|
|
|
767 |
|
|
/* |
768 |
|
|
* timeout_resolver - check request list |
769 |
|
|
*/ |
770 |
|
|
static void |
771 |
michael |
4438 |
timeout_resolver(void *unused) |
772 |
michael |
4312 |
{ |
773 |
|
|
timeout_query_list(); |
774 |
|
|
} |
775 |
|
|
|
776 |
|
|
/* |
777 |
|
|
* init_resolver - initialize resolver and resolver library |
778 |
|
|
*/ |
779 |
|
|
void |
780 |
|
|
init_resolver(void) |
781 |
|
|
{ |
782 |
|
|
static struct event event_timeout_resolver = |
783 |
|
|
{ |
784 |
|
|
.name = "timeout_resolver", |
785 |
|
|
.handler = timeout_resolver, |
786 |
|
|
.when = 1 |
787 |
|
|
}; |
788 |
|
|
|
789 |
|
|
dns_pool = mp_pool_new(sizeof(struct reslist), MP_CHUNK_SIZE_DNS); |
790 |
michael |
4421 |
|
791 |
michael |
4312 |
start_resolver(); |
792 |
|
|
event_add(&event_timeout_resolver, NULL); |
793 |
|
|
} |