1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2013 Adam <Adam@anope.org>
*
* This file is part of InspIRCd. InspIRCd is free software: you can
* redistribute it and/or modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "inspircd.h"
#include "modules/dns.h"
namespace
{
LocalIntExt* dl;
LocalStringExt* ph;
}
/** Derived from Resolver, and performs user forward/reverse lookups.
*/
class UserResolver : public DNS::Request
{
/** UUID we are looking up */
const std::string uuid;
/** True if the lookup is forward, false if is a reverse lookup
*/
const bool fwd;
public:
/** Create a resolver.
* @param mgr DNS Manager
* @param me this module
* @param user The user to begin lookup on
* @param to_resolve The IP or host to resolve
* @param qt The query type
*/
UserResolver(DNS::Manager* mgr, Module* me, LocalUser* user, const std::string& to_resolve, DNS::QueryType qt)
: DNS::Request(mgr, me, to_resolve, qt)
, uuid(user->uuid)
, fwd(qt == DNS::QUERY_A || qt == DNS::QUERY_AAAA)
{
}
/** Called on successful lookup
* if a previous result has already come back.
* @param r The finished query
*/
void OnLookupComplete(const DNS::Query* r)
{
LocalUser* bound_user = (LocalUser*)ServerInstance->FindUUID(uuid);
if (!bound_user)
{
ServerInstance->Logs->Log("RESOLVER", LOG_DEBUG, "Resolution finished for user '%s' who is gone", uuid.c_str());
return;
}
const DNS::ResourceRecord& ans_record = r->answers[0];
ServerInstance->Logs->Log("RESOLVER", LOG_DEBUG, "DNS result for %s: '%s' -> '%s'", uuid.c_str(), ans_record.name.c_str(), ans_record.rdata.c_str());
if (!fwd)
{
// first half of resolution is done. We now need to verify that the host matches.
ph->set(bound_user, ans_record.rdata);
UserResolver* res_forward;
if (bound_user->client_sa.sa.sa_family == AF_INET6)
{
/* IPV6 forward lookup */
res_forward = new UserResolver(this->manager, this->creator, bound_user, ans_record.rdata, DNS::QUERY_AAAA);
}
else
{
/* IPV4 lookup */
res_forward = new UserResolver(this->manager, this->creator, bound_user, ans_record.rdata, DNS::QUERY_A);
}
try
{
this->manager->Process(res_forward);
}
catch (DNS::Exception& e)
{
delete res_forward;
ServerInstance->Logs->Log("RESOLVER", LOG_DEBUG, "Error in resolver: %s",e.GetReason());
bound_user->WriteNotice("*** There was an internal error resolving your host, using your IP address (" + bound_user->GetIPString() + ") instead.");
dl->set(bound_user, 0);
}
}
else
{
/* Both lookups completed */
irc::sockets::sockaddrs* user_ip = &bound_user->client_sa;
bool rev_match = false;
if (user_ip->sa.sa_family == AF_INET6)
{
struct in6_addr res_bin;
if (inet_pton(AF_INET6, ans_record.rdata.c_str(), &res_bin))
{
rev_match = !memcmp(&user_ip->in6.sin6_addr, &res_bin, sizeof(res_bin));
}
}
else
{
struct in_addr res_bin;
if (inet_pton(AF_INET, ans_record.rdata.c_str(), &res_bin))
{
rev_match = !memcmp(&user_ip->in4.sin_addr, &res_bin, sizeof(res_bin));
}
}
dl->set(bound_user, 0);
if (rev_match)
{
std::string* hostname = ph->get(bound_user);
if (hostname == NULL)
{
ServerInstance->Logs->Log("RESOLVER", LOG_DEFAULT, "ERROR: User has no hostname attached when doing a forward lookup");
bound_user->WriteNotice("*** There was an internal error resolving your host, using your IP address (" + bound_user->GetIPString() + ") instead.");
return;
}
else if (hostname->length() < 65)
{
/* Hostnames starting with : are not a good thing (tm) */
if ((*hostname)[0] == ':')
hostname->insert(0, "0");
bound_user->WriteNotice("*** Found your hostname (" + *hostname + (r->cached ? ") -- cached" : ")"));
bound_user->host.assign(*hostname, 0, 64);
bound_user->dhost = bound_user->host;
/* Invalidate cache */
bound_user->InvalidateCache();
}
else
{
bound_user->WriteNotice("*** Your hostname is longer than the maximum of 64 characters, using your IP address (" + bound_user->GetIPString() + ") instead.");
}
ph->unset(bound_user);
}
else
{
bound_user->WriteNotice("*** Your hostname does not match up with your IP address. Sorry, using your IP address (" + bound_user->GetIPString() + ") instead.");
}
}
}
/** Called on failed lookup
* @param query The errored query
*/
void OnError(const DNS::Query* query)
{
LocalUser* bound_user = (LocalUser*)ServerInstance->FindUUID(uuid);
if (bound_user)
{
bound_user->WriteNotice("*** Could not resolve your hostname: " + this->manager->GetErrorStr(query->error) + "; using your IP address (" + bound_user->GetIPString() + ") instead.");
dl->set(bound_user, 0);
ServerInstance->stats->statsDnsBad++;
}
}
};
class ModuleHostnameLookup : public Module
{
LocalIntExt dnsLookup;
LocalStringExt ptrHosts;
dynamic_reference<DNS::Manager> DNS;
public:
ModuleHostnameLookup()
: dnsLookup("dnsLookup", this)
, ptrHosts("ptrHosts", this)
, DNS(this, "DNS")
{
dl = &dnsLookup;
ph = &ptrHosts;
}
void init()
{
ServerInstance->Modules->AddService(this->dnsLookup);
ServerInstance->Modules->AddService(this->ptrHosts);
}
void OnUserInit(LocalUser *user)
{
if (!DNS || !user->MyClass->resolvehostnames)
{
user->WriteNotice("*** Skipping host resolution (disabled by server administrator)");
return;
}
user->WriteNotice("*** Looking up your hostname...");
UserResolver* res_reverse = new UserResolver(*this->DNS, this, user, user->GetIPString(), DNS::QUERY_PTR);
try
{
/* If both the reverse and forward queries are cached, the user will be able to pass DNS completely
* before Process() completes, which is why dnsLookup.set() is here, before Process()
*/
this->dnsLookup.set(user, 1);
this->DNS->Process(res_reverse);
}
catch (DNS::Exception& e)
{
this->dnsLookup.set(user, 0);
delete res_reverse;
ServerInstance->Logs->Log("USERS", LOG_DEBUG, "Error in resolver: %s", e.GetReason());
ServerInstance->stats->statsDnsBad++;
}
}
ModResult OnCheckReady(LocalUser* user)
{
return this->dnsLookup.get(user) ? MOD_RES_DENY : MOD_RES_PASSTHRU;
}
Version GetVersion()
{
return Version("Provides support for DNS lookups on connecting clients", VF_CORE|VF_VENDOR);
}
};
MODULE_INIT(ModuleHostnameLookup)
|
