Commit | Line | Data |
---|---|---|
96779587 CH |
1 | /* |
2 | The software in this package is distributed under the GNU General | |
3 | Public License version 2 (with a special exception described below). | |
4 | ||
5 | A copy of GNU General Public License (GPL) is included in this distribution, | |
6 | in the file COPYING.GPL. | |
7 | ||
8 | As a special exception, if other files instantiate templates or use macros | |
9 | or inline functions from this file, or you compile this file and link it | |
10 | with other works to produce a work based on this file, this file | |
11 | does not by itself cause the resulting work to be covered | |
12 | by the GNU General Public License. | |
13 | ||
14 | However the source code for this file must still be made available | |
15 | in accordance with section (3) of the GNU General Public License. | |
16 | ||
17 | This exception does not invalidate any other reasons why a work based | |
18 | on this file might be covered by the GNU General Public License. | |
19 | ||
20 | Christian Herdtweck, Intra2net AG 2015 | |
21 | */ | |
22 | ||
c5b4902d | 23 | #include "dns/dnscache.h" |
96779587 | 24 | |
f636ba88 | 25 | #include <sstream> |
946356e1 | 26 | #include <fstream> |
96779587 | 27 | #include <logfunc.hpp> |
946356e1 | 28 | #include <filefunc.hxx> // I2n::file_exists |
e18c1337 | 29 | #include <boost/foreach.hpp> |
96779587 | 30 | #include <boost/bind.hpp> |
96779587 | 31 | #include <boost/asio/placeholders.hpp> |
946356e1 CH |
32 | #include <boost/serialization/serialization.hpp> |
33 | #include <boost/serialization/map.hpp> | |
34 | #include <boost/serialization/string.hpp> | |
35 | #include <boost/serialization/vector.hpp> | |
36 | #include <boost/archive/xml_oarchive.hpp> | |
37 | #include <boost/archive/xml_iarchive.hpp> | |
c98b5fcb | 38 | #include <boost/date_time/gregorian/gregorian_types.hpp> |
96779587 | 39 | |
dbe986b9 CH |
40 | #include "dns/dnsmaster.h" |
41 | ||
96779587 CH |
42 | using boost::bind; |
43 | using boost::posix_time::seconds; | |
44 | using I2n::Logger::GlobalLogger; | |
45 | ||
8d26221d | 46 | |
96779587 CH |
47 | namespace Config |
48 | { | |
77319ba8 | 49 | const int SAVE_TIMER_SECONDS = 60; |
81cf5681 | 50 | const int CACHE_TIME_WARP_THRESH_MINS = 10; |
4e691eb0 | 51 | const int CACHE_REMOVE_OUTDATED_DAYS = 60; |
96779587 CH |
52 | } |
53 | ||
8d26221d | 54 | |
f833126b CH |
55 | // ----------------------------------------------------------------------------- |
56 | // DNS Cache constructor / destructor | |
57 | // ----------------------------------------------------------------------------- | |
58 | ||
8d26221d CH |
59 | const string DnsCache::DoNotUseCacheFile = "do not use cache file!"; |
60 | ||
96779587 | 61 | DnsCache::DnsCache(const IoServiceItem &io_serv, |
f833126b CH |
62 | const std::string &cache_file, |
63 | const uint32_t min_time_between_resolves) | |
ad83004d CH |
64 | : IpCache() |
65 | , CnameCache() | |
96779587 CH |
66 | , SaveTimer( *io_serv ) |
67 | , CacheFile( cache_file ) | |
68 | , HasChanged( false ) | |
f833126b | 69 | , MinTimeBetweenResolves( min_time_between_resolves ) |
96779587 CH |
70 | { |
71 | // load cache from file | |
72 | load_from_cachefile(); | |
73 | ||
74 | // schedule next save | |
77319ba8 | 75 | (void) SaveTimer.expires_from_now( seconds( Config::SAVE_TIMER_SECONDS ) ); |
96779587 CH |
76 | SaveTimer.async_wait( bind( &DnsCache::schedule_save, this, |
77 | boost::asio::placeholders::error ) ); | |
78 | } | |
79 | ||
80 | ||
81 | DnsCache::~DnsCache() | |
82 | { | |
26b0f687 | 83 | GlobalLogger.info() << "DnsCache: being destructed"; |
e91538f0 | 84 | |
96779587 CH |
85 | // save one last time without re-scheduling the next save |
86 | save_to_cachefile(); | |
87 | ||
88 | // cancel save timer | |
89 | SaveTimer.cancel(); | |
90 | } | |
91 | ||
92 | ||
f833126b CH |
93 | // ----------------------------------------------------------------------------- |
94 | // LOAD / SAVE | |
95 | // ----------------------------------------------------------------------------- | |
96 | ||
96779587 CH |
97 | void DnsCache::schedule_save(const boost::system::error_code &error) |
98 | { | |
96779587 CH |
99 | if ( error == boost::asio::error::operation_aborted ) // cancelled |
100 | { | |
49b82a1d CH |
101 | GlobalLogger.info() << "DnsCache: SaveTimer was cancelled " |
102 | << "--> no save and no re-schedule of saving!"; | |
96779587 CH |
103 | return; |
104 | } | |
105 | else if (error) | |
106 | { | |
49b82a1d CH |
107 | GlobalLogger.info() << "DnsCache: Received error " << error |
108 | << " in schedule_save " | |
109 | << "--> no save now but re-schedule saving"; | |
96779587 CH |
110 | } |
111 | else | |
112 | save_to_cachefile(); | |
113 | ||
114 | // schedule next save | |
77319ba8 | 115 | (void) SaveTimer.expires_from_now( seconds( Config::SAVE_TIMER_SECONDS ) ); |
96779587 CH |
116 | SaveTimer.async_wait( bind( &DnsCache::schedule_save, this, |
117 | boost::asio::placeholders::error ) ); | |
118 | } | |
119 | ||
120 | void DnsCache::save_to_cachefile() | |
121 | { | |
122 | if (!HasChanged) | |
ad83004d | 123 | GlobalLogger.info() << "DnsCache: skip saving because has not changed"; |
946356e1 | 124 | else if (CacheFile.empty()) |
49b82a1d | 125 | GlobalLogger.info() |
ad83004d | 126 | << "DnsCache: skip saving because file name empty!"; |
8d26221d | 127 | else if (CacheFile == DoNotUseCacheFile) |
26b0f687 CH |
128 | GlobalLogger.info() << "DnsCache: configured not to use cache file"; |
129 | else | |
946356e1 | 130 | { |
26b0f687 CH |
131 | try |
132 | { | |
c98b5fcb CH |
133 | // clean up: remove very old entries |
134 | remove_old_entries(); | |
135 | ||
77319ba8 CH |
136 | // remember time of save |
137 | std::string cache_save_time_str = boost::posix_time::to_iso_string( | |
138 | boost::posix_time::second_clock::universal_time() ); | |
139 | ||
26b0f687 CH |
140 | std::ofstream ofs( CacheFile.c_str() ); |
141 | boost::archive::xml_oarchive oa(ofs); | |
26b0f687 CH |
142 | oa & BOOST_SERIALIZATION_NVP(IpCache); |
143 | oa & BOOST_SERIALIZATION_NVP(CnameCache); | |
77319ba8 | 144 | oa & BOOST_SERIALIZATION_NVP(cache_save_time_str); |
8d26221d CH |
145 | GlobalLogger.info() << "DnsCache: saved to cache file " |
146 | << CacheFile; | |
26b0f687 CH |
147 | |
148 | HasChanged = false; | |
149 | } | |
150 | catch (std::exception &exc) | |
151 | { | |
c1abff61 | 152 | GlobalLogger.warning() << "DnsCache: Saving failed: " << exc.what(); |
26b0f687 | 153 | } |
946356e1 | 154 | } |
96779587 CH |
155 | } |
156 | ||
96779587 CH |
157 | void DnsCache::load_from_cachefile() |
158 | { | |
946356e1 | 159 | if (CacheFile.empty()) |
49b82a1d | 160 | GlobalLogger.info() |
8d26221d CH |
161 | << "DnsCache: cannot load because cache file name is empty!"; |
162 | else if (CacheFile == DoNotUseCacheFile) | |
26b0f687 | 163 | GlobalLogger.info() << "DnsCache: configured not to use cache file"; |
946356e1 | 164 | else if ( !I2n::file_exists(CacheFile) ) |
ad83004d | 165 | GlobalLogger.warning() << "DnsCache: cannot load because cache file " |
946356e1 | 166 | << CacheFile << " does not exist!"; |
26b0f687 | 167 | else |
946356e1 | 168 | { |
26b0f687 CH |
169 | try |
170 | { | |
171 | std::ifstream ifs( CacheFile.c_str() ); | |
172 | boost::archive::xml_iarchive ia(ifs); | |
946356e1 | 173 | |
d92e7d02 TJ |
174 | ip_map_type new_IpCache; |
175 | cname_map_type new_CnameCache; | |
77319ba8 CH |
176 | std::string cache_save_time_str; |
177 | ||
d92e7d02 TJ |
178 | ia & BOOST_SERIALIZATION_NVP(new_IpCache); |
179 | ia & BOOST_SERIALIZATION_NVP(new_CnameCache); | |
77319ba8 CH |
180 | ia & BOOST_SERIALIZATION_NVP(cache_save_time_str); |
181 | ||
d92e7d02 | 182 | const boost::posix_time::ptime cache_save_time |
77319ba8 | 183 | = boost::posix_time::from_iso_string(cache_save_time_str); |
26b0f687 | 184 | GlobalLogger.info() << "DnsCache: loaded from file " << CacheFile; |
77319ba8 | 185 | |
d92e7d02 TJ |
186 | // atomic switch over |
187 | IpCache.swap(new_IpCache); | |
188 | CnameCache.swap(new_CnameCache); | |
189 | ||
77319ba8 | 190 | check_timestamps(cache_save_time); |
26b0f687 CH |
191 | } |
192 | catch (boost::archive::archive_exception &exc) | |
193 | { | |
8d26221d CH |
194 | GlobalLogger.warning() |
195 | << "DnsCache: archive exception loading from " << CacheFile | |
196 | << ": " << exc.what(); | |
26b0f687 CH |
197 | } |
198 | catch (std::exception &exc) | |
199 | { | |
200 | GlobalLogger.warning() << "DnsCache: exception while loading from " | |
201 | << CacheFile << ": " << exc.what(); | |
202 | } | |
946356e1 | 203 | } |
96779587 CH |
204 | } |
205 | ||
26b0f687 | 206 | |
77319ba8 CH |
207 | /** |
208 | * @brief check that loaded cache really is from the past | |
209 | * | |
210 | * Added this to avoid trouble in case the system time is changed into the past. | |
64a85329 | 211 | * In that case would have TTLs here in cache that are valid much too long. |
77319ba8 CH |
212 | * |
213 | * Therefore check SaveCacheTime and if that is in the future, set all TTLs to 0 | |
214 | * | |
215 | * @returns true if had to re-set timestamps | |
216 | */ | |
217 | bool DnsCache::check_timestamps(const boost::posix_time::ptime &cache_save_time) | |
218 | { | |
219 | // check if CacheSaveTime is in the future | |
220 | boost::posix_time::ptime now | |
221 | = boost::posix_time::second_clock::universal_time() | |
81cf5681 | 222 | + boost::posix_time::minutes(Config::CACHE_TIME_WARP_THRESH_MINS); |
77319ba8 CH |
223 | if (now > cache_save_time) |
224 | { // Cache was saved in the past -- everything alright | |
225 | return false; | |
226 | } | |
227 | ||
228 | GlobalLogger.warning() << "DnsCache: loaded cache from the future (saved " | |
229 | << cache_save_time << ")! Resetting all TTLs to 0."; | |
230 | ||
231 | // reset TTLs in IP cache | |
81cf5681 | 232 | BOOST_FOREACH( ip_map_type::value_type &key_and_ip, IpCache ) |
77319ba8 | 233 | { |
81cf5681 CH |
234 | BOOST_FOREACH( HostAddress &address, key_and_ip.second ) |
235 | address.get_ttl().set_value(0); | |
77319ba8 CH |
236 | } |
237 | ||
238 | // reset TTLs in CNAME cache | |
81cf5681 CH |
239 | BOOST_FOREACH( cname_map_type::value_type &key_and_cname, CnameCache ) |
240 | key_and_cname.second.Ttl.set_value(0); | |
241 | ||
242 | HasChanged = true; | |
243 | ||
244 | //debug_print(); | |
77319ba8 CH |
245 | |
246 | return true; | |
247 | } | |
248 | ||
249 | ||
c98b5fcb CH |
250 | /** |
251 | * @brief remove entries from cache that are older than a certain threshold | |
252 | * | |
253 | * this also removes entres from IpCache with no IPs | |
254 | */ | |
255 | void DnsCache::remove_old_entries() | |
256 | { | |
257 | boost::posix_time::ptime thresh | |
258 | = boost::posix_time::second_clock::universal_time() | |
259 | - boost::gregorian::days( Config::CACHE_REMOVE_OUTDATED_DAYS ); | |
260 | ||
261 | // IP cache | |
c98b5fcb | 262 | { |
81cf5681 CH |
263 | ip_map_type::iterator it = IpCache.begin(); |
264 | ip_map_type::iterator it_end = IpCache.end(); | |
265 | bool some_ip_up_to_date; | |
266 | while (it != it_end) | |
c98b5fcb | 267 | { |
81cf5681 CH |
268 | some_ip_up_to_date = false; |
269 | BOOST_FOREACH( const HostAddress &address, (*it).second ) | |
c98b5fcb | 270 | { |
81cf5681 CH |
271 | if ( ! address.get_ttl().was_set_before(thresh) ) |
272 | { | |
273 | some_ip_up_to_date = true; | |
274 | break; | |
275 | } | |
c98b5fcb | 276 | } |
c98b5fcb | 277 | |
81cf5681 CH |
278 | if ( ! some_ip_up_to_date ) |
279 | { | |
280 | GlobalLogger.debug() << "DnsCache: Removing empty/outdated IP " | |
281 | << "list for " << (*it).first.first; | |
282 | IpCache.erase( (*it++).first ); | |
283 | } | |
284 | else | |
285 | ++it; | |
c98b5fcb CH |
286 | } |
287 | } | |
288 | ||
289 | // CNAME cache | |
c98b5fcb | 290 | { |
81cf5681 CH |
291 | cname_map_type::iterator it = CnameCache.begin(); |
292 | cname_map_type::iterator it_end = CnameCache.end(); | |
293 | while (it != it_end) | |
c98b5fcb | 294 | { |
81cf5681 CH |
295 | if ( (*it).second.Ttl.was_set_before( thresh ) ) |
296 | { | |
297 | GlobalLogger.debug() << "DnsCache: Removing outdated CNAME for " | |
298 | << (*it).first; | |
299 | CnameCache.erase( (*it++).first ); | |
300 | } | |
301 | else | |
302 | ++it; | |
c98b5fcb CH |
303 | } |
304 | } | |
305 | } | |
306 | ||
f833126b CH |
307 | // ----------------------------------------------------------------------------- |
308 | // UPDATE | |
309 | // ----------------------------------------------------------------------------- | |
310 | ||
8f00b3df CH |
311 | /* |
312 | * warn if hostname is empty and remove trailing dot | |
313 | * also warn if protocol is neither IPv4 nor IPv6 | |
314 | */ | |
315 | ip_map_key_type DnsCache::key_for_ips(const std::string &hostname, | |
316 | const DnsIpProtocol &protocol) const | |
96779587 | 317 | { |
26b0f687 CH |
318 | if (hostname.empty()) |
319 | { | |
49b82a1d | 320 | GlobalLogger.info() << "DnsCache: empty host!"; |
8f00b3df CH |
321 | return ip_map_key_type("", DNS_IPALL); |
322 | } | |
323 | if (protocol == DNS_IPALL) | |
324 | { | |
325 | GlobalLogger.info() << "DnsCache: neither IPv4 nor v6!"; | |
326 | return ip_map_key_type("", DNS_IPALL); | |
26b0f687 CH |
327 | } |
328 | ||
329 | // check whether last character is a dot | |
330 | if (hostname.rfind('.') == hostname.length()-1) | |
8f00b3df CH |
331 | return ip_map_key_type( hostname.substr(0, hostname.length()-1), |
332 | protocol ); | |
26b0f687 | 333 | else |
8f00b3df CH |
334 | return ip_map_key_type( hostname, |
335 | protocol ); | |
96779587 CH |
336 | } |
337 | ||
338 | ||
ad83004d | 339 | void DnsCache::update(const std::string &hostname, |
8f00b3df | 340 | const DnsIpProtocol &protocol, |
26b0f687 | 341 | const HostAddressVec &new_ips) |
ad83004d | 342 | { |
8f00b3df CH |
343 | // check for valid input arguments |
344 | ip_map_key_type key = key_for_ips(hostname, protocol); | |
345 | if ( key.first.empty() ) | |
346 | return; | |
347 | ||
348 | // ensure that there is never IP and CNAME for the same host | |
26b0f687 | 349 | if ( !get_cname(hostname).Host.empty() ) |
8f00b3df CH |
350 | { |
351 | GlobalLogger.info() << "DnsCache: Saving IPs for " << key.first | |
26b0f687 CH |
352 | << " removes CNAME to " << get_cname(hostname).Host << "!"; |
353 | update(hostname, Cname()); // overwrite with "empty" cname | |
354 | } | |
8f00b3df | 355 | |
f833126b CH |
356 | // ensure min ttl of MinTimeBetweenResolves |
357 | HostAddressVec ips_checked; | |
358 | BOOST_FOREACH( const HostAddress &addr, new_ips ) | |
359 | { | |
360 | if ( addr.get_ttl().get_value() < MinTimeBetweenResolves ) | |
361 | { | |
362 | GlobalLogger.info() << "DnsCache: Correcting TTL of IP for " | |
8f00b3df | 363 | << key.first << " from " << addr.get_ttl().get_value() << "s to " |
f833126b CH |
364 | << MinTimeBetweenResolves << "s because was too short"; |
365 | ips_checked.push_back( HostAddress( addr.get_ip(), | |
366 | MinTimeBetweenResolves) ); | |
367 | } | |
368 | else | |
369 | ips_checked.push_back(addr); | |
370 | } | |
371 | ||
8f00b3df | 372 | // write IPs into one log line |
f636ba88 | 373 | stringstream log_temp; |
8f00b3df | 374 | log_temp << "DnsCache: update IPs for " << key.first << " to " |
f636ba88 CH |
375 | << ips_checked.size() << "-list: "; |
376 | BOOST_FOREACH( const HostAddress &ip, ips_checked ) | |
377 | log_temp << ip.get_ip() << ", "; | |
378 | GlobalLogger.notice() << log_temp.str(); | |
f833126b CH |
379 | |
380 | IpCache[key] = ips_checked; | |
ad83004d CH |
381 | HasChanged = true; |
382 | } | |
383 | ||
384 | ||
8f00b3df CH |
385 | /* |
386 | * warn if hostname is empty and remove trailing dot | |
387 | */ | |
388 | cname_map_key_type DnsCache::key_for_cname(const std::string &hostname) const | |
389 | { | |
390 | if (hostname.empty()) | |
391 | { | |
392 | GlobalLogger.info() << "DnsCache: empty host!"; | |
393 | return ""; | |
394 | } | |
395 | ||
396 | // check whether last character is a dot | |
397 | if (hostname.rfind('.') == hostname.length()-1) | |
398 | return hostname.substr(0, hostname.length()-1); | |
399 | else | |
400 | return hostname; | |
401 | } | |
402 | ||
403 | ||
dbe986b9 | 404 | void DnsCache::update(const std::string &hostname, |
26b0f687 | 405 | const Cname &cname) |
ad83004d | 406 | { |
8f00b3df CH |
407 | // check for valid input arguments |
408 | cname_map_key_type key = key_for_cname(hostname); | |
409 | if ( key.empty() ) | |
410 | return; | |
411 | ||
412 | // ensure that there is never IP and CNAME for the same host | |
413 | int n_ips = get_ips(hostname, DNS_IPv4).size() | |
414 | + get_ips(hostname, DNS_IPv6).size(); | |
415 | if ( n_ips > 0 ) | |
416 | { | |
417 | GlobalLogger.info() << "DnsCache: Saving IPs for " << key | |
418 | << " removes CNAME to " << get_cname(hostname).Host << "!"; | |
49b82a1d | 419 | GlobalLogger.info() << "DnsCache: Saving CNAME for " << key |
8f00b3df CH |
420 | << " removes " << n_ips << " IPs for same host!"; |
421 | update(hostname, DNS_IPv4, HostAddressVec()); | |
422 | update(hostname, DNS_IPv6, HostAddressVec()); | |
ad83004d | 423 | } |
26b0f687 | 424 | |
8f00b3df CH |
425 | // remove possible trailing dot from cname's target host |
426 | Cname to_save = Cname(key_for_cname(cname.Host), // implicit cast to string | |
26b0f687 CH |
427 | cname.Ttl); |
428 | ||
f833126b CH |
429 | // ensure min ttl of MinTimeBetweenResolves |
430 | if ( to_save.Ttl.get_value() < MinTimeBetweenResolves ) | |
431 | { | |
432 | GlobalLogger.info() << "DnsCache: Correcting TTL of CNAME of " | |
8f00b3df | 433 | << key << " from " << to_save.Ttl.get_value() << "s to " |
f833126b CH |
434 | << MinTimeBetweenResolves << "s because was too short"; |
435 | to_save.Ttl = TimeToLive(MinTimeBetweenResolves); | |
436 | } | |
437 | ||
f636ba88 | 438 | GlobalLogger.notice() << "DnsCache: update CNAME for " << key |
8f00b3df | 439 | << " to " << to_save.Host; |
26b0f687 CH |
440 | CnameCache[key] = to_save; |
441 | HasChanged = true; | |
ad83004d CH |
442 | } |
443 | ||
444 | ||
f833126b CH |
445 | // ----------------------------------------------------------------------------- |
446 | // RETRIEVAL | |
447 | // ----------------------------------------------------------------------------- | |
448 | ||
23f51766 CH |
449 | /** |
450 | * @returns empty list if no (up to date) ips for hostname in cache | |
451 | */ | |
dbe986b9 | 452 | HostAddressVec DnsCache::get_ips(const std::string &hostname, |
8f00b3df | 453 | const DnsIpProtocol &protocol, |
dbe986b9 | 454 | const bool check_up_to_date) |
96779587 | 455 | { |
8f00b3df | 456 | ip_map_key_type key = key_for_ips(hostname, protocol); |
26b0f687 | 457 | HostAddressVec result = IpCache[key]; |
dbe986b9 CH |
458 | if (check_up_to_date) |
459 | { | |
460 | HostAddressVec result_up_to_date; | |
23f51766 CH |
461 | uint32_t threshold = static_cast<uint32_t>( |
462 | DnsMaster::get_instance()->get_resolved_ip_ttl_threshold() ); | |
26b0f687 | 463 | uint32_t updated_ttl; |
dbe986b9 CH |
464 | BOOST_FOREACH( const HostAddress &addr, result ) |
465 | { | |
26b0f687 CH |
466 | updated_ttl = addr.get_ttl().get_updated_value(); |
467 | if (updated_ttl > threshold) | |
dbe986b9 | 468 | result_up_to_date.push_back(addr); |
26b0f687 CH |
469 | else |
470 | GlobalLogger.debug() << "DnsCache: do not return " | |
471 | << addr.get_ip().to_string() << " since TTL " | |
472 | << updated_ttl << "s is out of date (thresh=" | |
473 | << threshold << "s)"; | |
dbe986b9 | 474 | } |
dbe986b9 CH |
475 | result = result_up_to_date; |
476 | } | |
8f00b3df | 477 | /*GlobalLogger.debug() << "DnsCache: request IPs for " << key.first |
26b0f687 CH |
478 | << " --> " << result.size() << "-list"; |
479 | BOOST_FOREACH( const HostAddress &addr, result ) | |
480 | GlobalLogger.debug() << "DnsCache: " << addr.get_ip().to_string() | |
fd62d09f | 481 | << " (TTL " << addr.get_ttl().get_updated_value() |
2a4dde8b | 482 | << "s)"; */ |
dbe986b9 | 483 | return result; |
96779587 CH |
484 | } |
485 | ||
23f51766 CH |
486 | /** |
487 | * @returns empty cname if no (up to date cname) for hostname in cache | |
488 | */ | |
489 | Cname DnsCache::get_cname(const std::string &hostname, | |
490 | const bool check_up_to_date) | |
ad83004d | 491 | { |
8f00b3df | 492 | cname_map_key_type key = key_for_cname(hostname); |
26b0f687 | 493 | Cname result_obj = CnameCache[key]; |
2a4dde8b | 494 | /*GlobalLogger.debug() << "DnsCache: request CNAME for " << key |
fd62d09f | 495 | << " --> \"" << result_obj.Host << "\" (TTL " |
2a4dde8b | 496 | << result_obj.Ttl.get_updated_value() << "s)";*/ |
23f51766 CH |
497 | if (result_obj.Host.empty()) |
498 | return result_obj; | |
499 | ||
500 | else if (check_up_to_date) | |
dbe986b9 | 501 | { |
26b0f687 CH |
502 | if ( result_obj.Ttl.get_updated_value() > static_cast<uint32_t>( |
503 | DnsMaster::get_instance()->get_resolved_ip_ttl_threshold()) ) | |
23f51766 | 504 | return result_obj; |
dbe986b9 CH |
505 | else |
506 | { | |
23f51766 CH |
507 | GlobalLogger.debug() << "DnsCache: CNAME is out of date"; |
508 | return Cname(); // same as if there was no cname for hostname | |
dbe986b9 CH |
509 | } |
510 | } | |
511 | else | |
23f51766 | 512 | return result_obj; |
ad83004d CH |
513 | } |
514 | ||
dbe986b9 CH |
515 | // underlying assumption in this function: for a hostname, the cache has either |
516 | // a list of IPs saved or a cname saved, but never both | |
517 | HostAddressVec DnsCache::get_ips_recursive(const std::string &hostname, | |
8f00b3df | 518 | const DnsIpProtocol &protocol, |
dbe986b9 | 519 | const bool check_up_to_date) |
e18c1337 CH |
520 | { |
521 | std::string current_host = hostname; | |
23f51766 | 522 | Cname current_cname; |
8f00b3df | 523 | HostAddressVec result = get_ips(current_host, protocol, check_up_to_date); |
dbe986b9 | 524 | int n_recursions = 0; |
23f51766 | 525 | uint32_t min_cname_ttl = 0xffff; // largest possible unsigned 4-byte value |
cd71d095 CH |
526 | int max_recursion_count = DnsMaster::get_instance() |
527 | ->get_max_recursion_count(); | |
e18c1337 CH |
528 | while ( result.empty() ) |
529 | { | |
23f51766 | 530 | current_cname = get_cname(current_host, check_up_to_date); |
8d26221d | 531 | if (current_cname.Host.empty()) |
8f00b3df CH |
532 | break; // no ips (since result.empty()) and no cname |
533 | // --> will return empty result | |
8d26221d | 534 | |
8f00b3df | 535 | current_host = current_cname.Host; |
cd71d095 | 536 | if (++n_recursions >= max_recursion_count) |
dbe986b9 | 537 | { |
49b82a1d CH |
538 | GlobalLogger.info() << "DnsCache: reached recursion limit of " |
539 | << n_recursions << " in recursive IP retrieval of " | |
540 | << hostname << "!"; | |
dbe986b9 CH |
541 | break; |
542 | } | |
e18c1337 | 543 | else |
23f51766 | 544 | { |
fd62d09f CH |
545 | min_cname_ttl = min(min_cname_ttl, |
546 | current_cname.Ttl.get_updated_value()); | |
8f00b3df | 547 | result = get_ips(current_host, protocol, check_up_to_date); |
23f51766 CH |
548 | } |
549 | } | |
550 | ||
551 | GlobalLogger.debug() << "DnsCache: recursive IP retrieval resulted in " | |
552 | << result.size() << "-list after " << n_recursions | |
553 | << " recursions"; | |
554 | ||
555 | // adjust ttl to min of ttl and min_cname_ttl | |
556 | if (n_recursions > 0) | |
557 | { | |
558 | TimeToLive cname_ttl(min_cname_ttl); | |
559 | ||
560 | BOOST_FOREACH( HostAddress &addr, result ) | |
561 | { | |
fd62d09f | 562 | if (addr.get_ttl().get_updated_value() > min_cname_ttl) |
8d26221d | 563 | { |
2a4dde8b | 564 | //GlobalLogger.debug() << "DnsCache: using shorter CNAME TTL"; |
23f51766 | 565 | addr.set_ttl(cname_ttl); |
8d26221d | 566 | } |
23f51766 | 567 | } |
e18c1337 | 568 | } |
23f51766 | 569 | |
e18c1337 CH |
570 | return result; |
571 | } | |
ad83004d | 572 | |
23f51766 | 573 | /** |
9d1b2726 CH |
574 | * from a list of CNAMEs find the first one that is out of date or empty |
575 | * | |
576 | * returns the hostname that is out of date or empty if all CNAMEs are | |
577 | * up-to-date | |
23f51766 CH |
578 | * |
579 | * required in ResolverBase::get_skipper | |
23f51766 CH |
580 | */ |
581 | std::string DnsCache::get_first_outdated_cname(const std::string &hostname, | |
582 | const uint32_t ttl_thresh) | |
583 | { | |
8d26221d | 584 | std::string first_outdated = hostname; |
23f51766 CH |
585 | Cname cname; |
586 | int n_recursions = 0; | |
cd71d095 CH |
587 | int max_recursion_count = DnsMaster::get_instance() |
588 | ->get_max_recursion_count(); | |
23f51766 CH |
589 | while (true) |
590 | { | |
cd71d095 | 591 | if (++n_recursions >= max_recursion_count) |
23f51766 | 592 | { |
49b82a1d CH |
593 | GlobalLogger.info() << "DnsCache: reached recursion limit of " |
594 | << n_recursions << " in search of outdated CNAMEs for " | |
595 | << hostname << "!"; | |
9d1b2726 CH |
596 | return first_outdated; // not really out of date but currently |
597 | } // our best guess | |
23f51766 | 598 | |
8d26221d CH |
599 | cname = get_cname(first_outdated); |
600 | if (cname.Host.empty()) | |
9d1b2726 CH |
601 | // reached end of cname list --> everything was up-to-date |
602 | return ""; | |
23f51766 CH |
603 | else if (cname.Ttl.get_updated_value() > ttl_thresh) |
604 | // cname is up to date --> continue looking | |
8d26221d | 605 | first_outdated = cname.Host; |
23f51766 | 606 | else |
9d1b2726 CH |
607 | // cname is out of date --> return its target |
608 | return cname.Host; | |
23f51766 | 609 | } |
9d1b2726 CH |
610 | // reach this point only if cname chain does not end with an IP |
611 | // --> all are up-to-date | |
612 | return ""; | |
23f51766 | 613 | } |
e638894d CH |
614 | |
615 | std::string DnsCache::get_cname_chain_str(const std::string &hostname) | |
616 | { | |
617 | std::stringstream temp; | |
618 | temp << hostname; | |
619 | std::string current_host = hostname; | |
620 | Cname current_cname; | |
621 | int n_recursions = 0; | |
622 | int max_recursion_count = DnsMaster::get_instance() | |
623 | ->get_max_recursion_count(); | |
624 | while (true) | |
625 | { | |
626 | if (n_recursions >= max_recursion_count) | |
627 | { | |
628 | temp << "..."; | |
629 | break; | |
630 | } | |
631 | ||
632 | current_cname = get_cname(current_host, false); | |
633 | if (current_cname.Host.empty()) | |
634 | break; | |
635 | else | |
636 | { | |
637 | current_host = current_cname.Host; | |
638 | temp << "-->" << current_host; | |
a176d17a | 639 | ++n_recursions; |
e638894d CH |
640 | } |
641 | } | |
642 | return temp.str(); | |
643 | } | |
81cf5681 CH |
644 | |
645 | ||
646 | // ----------------------------------------------------------------------------- | |
647 | // OTHER | |
648 | // ----------------------------------------------------------------------------- | |
649 | void DnsCache::debug_print() const | |
650 | { | |
651 | GlobalLogger.debug() << "DnsCache: IP Cache contents:"; | |
652 | stringstream log_temp; | |
653 | BOOST_FOREACH( const ip_map_type::value_type &key_and_ip, IpCache ) | |
654 | { | |
655 | // write IPs into one log line | |
656 | log_temp.str(""); | |
657 | log_temp << "DnsCache: " << key_and_ip.first.first << ": \t " | |
658 | << key_and_ip.second.size() << "-list "; | |
659 | BOOST_FOREACH( const HostAddress &ip, key_and_ip.second ) | |
660 | log_temp << ip.get_ip() << "+" << ip.get_ttl().get_updated_value() | |
661 | << "s, "; | |
662 | GlobalLogger.debug() << log_temp.str(); | |
663 | } | |
664 | ||
665 | GlobalLogger.debug() << "DnsCache: CNAME Cache contents:"; | |
666 | BOOST_FOREACH( const cname_map_type::value_type &key_and_cname, CnameCache ) | |
667 | GlobalLogger.debug() << "DnsCache: " << key_and_cname.first << ": \t " | |
668 | << key_and_cname.second.Host << "+" | |
669 | << key_and_cname.second.Ttl.get_updated_value() | |
670 | << "s"; | |
671 | } |