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
|
/*
Copyright (C) 2021 The Falco Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#include "dns_manager.h"
void sinsp_dns_resolver::refresh(uint64_t erase_timeout, uint64_t base_refresh_timeout, uint64_t max_refresh_timeout, std::future<void> f_exit)
{
#if defined(HAS_CAPTURE) && !defined(CYGWING_AGENT) && !defined(_WIN32)
sinsp_dns_manager &manager = sinsp_dns_manager::get();
while(true)
{
if(!manager.m_cache.empty())
{
std::list<std::string> to_delete;
uint64_t ts = sinsp_utils::get_current_time_ns();
for(auto &it: manager.m_cache)
{
const std::string &name = it.first;
sinsp_dns_manager::dns_info &info = it.second;
if((ts > info.m_last_used_ts) &&
(ts - info.m_last_used_ts) > erase_timeout)
{
// remove the entry if it's hasn't been used for a whole hour
to_delete.push_back(name);
}
else if(ts > (info.m_last_resolve_ts + info.m_timeout))
{
sinsp_dns_manager::dns_info refreshed_info = manager.resolve(name, ts);
refreshed_info.m_timeout = base_refresh_timeout;
refreshed_info.m_last_resolve_ts = info.m_last_resolve_ts = ts;
// dns_info::operator!= will check if some
// v4 or v6 addresses are changed from the
// last resolution
if(refreshed_info != info)
{
info = refreshed_info;
}
else if(info.m_timeout < max_refresh_timeout)
{
// double the timeout until 320 secs
info.m_timeout <<= 1;
}
}
}
if(!to_delete.empty())
{
manager.m_erase_mutex.lock();
for(const auto &name : to_delete)
{
manager.m_cache.unsafe_erase(name);
}
manager.m_erase_mutex.unlock();
}
}
if(f_exit.wait_for(std::chrono::nanoseconds(base_refresh_timeout)) == std::future_status::ready)
{
break;
}
}
#endif
}
#if defined(HAS_CAPTURE) && !defined(CYGWING_AGENT) && !defined(_WIN32)
inline sinsp_dns_manager::dns_info sinsp_dns_manager::resolve(const std::string &name, uint64_t ts)
{
dns_info dinfo;
struct addrinfo hints, *result, *rp;
memset(&hints, 0, sizeof(struct addrinfo));
// Allow IPv4 or IPv6, all socket types, all protocols
hints.ai_family = AF_UNSPEC;
int s = getaddrinfo(name.c_str(), NULL, &hints, &result);
if (!s && result)
{
for (rp = result; rp != NULL; rp = rp->ai_next)
{
if(rp->ai_family == AF_INET)
{
dinfo.m_v4_addrs.insert(((struct sockaddr_in*)rp->ai_addr)->sin_addr.s_addr);
}
else // AF_INET6
{
ipv6addr v6;
memcpy(v6.m_b, ((struct sockaddr_in6*)rp->ai_addr)->sin6_addr.s6_addr, sizeof(ipv6addr));
dinfo.m_v6_addrs.insert(v6);
}
}
freeaddrinfo(result);
}
return dinfo;
}
#endif
bool sinsp_dns_manager::match(const char *name, int af, void *addr, uint64_t ts)
{
#if defined(HAS_CAPTURE) && !defined(CYGWING_AGENT) && !defined(_WIN32)
if(!m_resolver)
{
m_resolver = new thread(sinsp_dns_resolver::refresh, m_erase_timeout, m_base_refresh_timeout, m_max_refresh_timeout, m_exit_signal.get_future());
}
string sname = string(name);
m_erase_mutex.lock();
if(m_cache.find(sname) == m_cache.end())
{
dns_info dinfo = resolve(sname, ts);
dinfo.m_timeout = m_base_refresh_timeout;
dinfo.m_last_resolve_ts = ts;
m_cache[sname] = dinfo;
}
m_cache[sname].m_last_used_ts = ts;
dns_info &dinfo = m_cache[sname];
m_erase_mutex.unlock();
if(af == AF_INET6)
{
ipv6addr v6;
memcpy(v6.m_b, addr, sizeof(ipv6addr));
return dinfo.m_v6_addrs.find(v6) != dinfo.m_v6_addrs.end();
}
else if(af == AF_INET)
{
return dinfo.m_v4_addrs.find(*(uint32_t *)addr) != dinfo.m_v4_addrs.end();
}
#endif
return false;
}
string sinsp_dns_manager::name_of(int af, void *addr, uint64_t ts)
{
string ret;
#if defined(HAS_CAPTURE) && !defined(CYGWING_AGENT) && !defined(_WIN32)
if(!m_cache.empty())
{
m_erase_mutex.lock();
for(auto &it: m_cache)
{
const std::string &name = it.first;
sinsp_dns_manager::dns_info &info = it.second;
if(af == AF_INET6)
{
ipv6addr v6;
memcpy(v6.m_b, addr, sizeof(ipv6addr));
if (info.m_v6_addrs.find(v6) != info.m_v6_addrs.end())
{
info.m_last_used_ts = ts;
ret = name;
break;
}
}
else if(af == AF_INET && info.m_v4_addrs.find(*(uint32_t *)addr) != info.m_v4_addrs.end())
{
info.m_last_used_ts = ts;
ret = name;
break;
}
}
m_erase_mutex.unlock();
}
#endif
return ret;
}
void sinsp_dns_manager::cleanup()
{
if(m_resolver)
{
m_exit_signal.set_value();
m_resolver->join();
m_resolver = NULL;
m_exit_signal = std::promise<void>();
}
}
|
