Kea  2.1.7-git
query_filter.cc
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1 // Copyright (C) 2018-2020 Internet Systems Consortium, Inc. ("ISC")
2 //
3 // This Source Code Form is subject to the terms of the Mozilla Public
4 // License, v. 2.0. If a copy of the MPL was not distributed with this
5 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
6 
7 #include <config.h>
8 
9 #include <ha_log.h>
10 #include <query_filter.h>
11 #include <dhcp/dhcp4.h>
12 #include <dhcp/dhcp6.h>
13 #include <dhcp/option.h>
14 #include <exceptions/exceptions.h>
16 
17 #include <array>
18 #include <iostream>
19 #include <sstream>
20 
21 using namespace isc::dhcp;
22 using namespace isc::log;
23 using namespace isc::util;
24 
25 namespace {
26 
30 std::array<uint8_t, 256> loadb_mx_tbl = { {
31  251, 175, 119, 215, 81, 14, 79, 191, 103, 49, 181, 143, 186, 157, 0,
32  232, 31, 32, 55, 60, 152, 58, 17, 237, 174, 70, 160, 144, 220, 90, 57,
33  223, 59, 3, 18, 140, 111, 166, 203, 196, 134, 243, 124, 95, 222, 179,
34  197, 65, 180, 48, 36, 15, 107, 46, 233, 130, 165, 30, 123, 161, 209, 23,
35  97, 16, 40, 91, 219, 61, 100, 10, 210, 109, 250, 127, 22, 138, 29, 108,
36  244, 67, 207, 9, 178, 204, 74, 98, 126, 249, 167, 116, 34, 77, 193,
37  200, 121, 5, 20, 113, 71, 35, 128, 13, 182, 94, 25, 226, 227, 199, 75,
38  27, 41, 245, 230, 224, 43, 225, 177, 26, 155, 150, 212, 142, 218, 115,
39  241, 73, 88, 105, 39, 114, 62, 255, 192, 201, 145, 214, 168, 158, 221,
40  148, 154, 122, 12, 84, 82, 163, 44, 139, 228, 236, 205, 242, 217, 11,
41  187, 146, 159, 64, 86, 239, 195, 42, 106, 198, 118, 112, 184, 172, 87,
42  2, 173, 117, 176, 229, 247, 253, 137, 185, 99, 164, 102, 147, 45, 66,
43  231, 52, 141, 211, 194, 206, 246, 238, 56, 110, 78, 248, 63, 240, 189,
44  93, 92, 51, 53, 183, 19, 171, 72, 50, 33, 104, 101, 69, 8, 252, 83, 120,
45  76, 135, 85, 54, 202, 125, 188, 213, 96, 235, 136, 208, 162, 129, 190,
46  132, 156, 38, 47, 1, 7, 254, 24, 4, 216, 131, 89, 21, 28, 133, 37, 153,
47  149, 80, 170, 68, 6, 169, 234, 151 }
48 };
49 
50 } // end of anonymous namespace
51 
52 namespace isc {
53 namespace ha {
54 
55 QueryFilter::QueryFilter(const HAConfigPtr& config)
56  : config_(config), peers_(), scopes_(), active_servers_(0),
57  mutex_(new std::mutex) {
58 
59  // Make sure that the configuration is valid. We make certain
60  // assumptions about the availability of the servers' configurations
61  // in the config_ structure.
62  config_->validate();
63 
64  HAConfig::PeerConfigMap peers_map = config->getAllServersConfig();
65  std::vector<HAConfig::PeerConfigPtr> backup_peers;
66 
67  // The returned configurations are not ordered. Let's iterate over them
68  // and put them in the desired order.
69  for (auto peer_pair = peers_map.begin(); peer_pair != peers_map.end(); ++peer_pair) {
70  auto peer = peer_pair->second;
71  // The primary server is always first on the list.
72  if (peer->getRole() == HAConfig::PeerConfig::PRIMARY) {
73  peers_.insert(peers_.begin(), peer);
75 
76  // The secondary server is always behind the primary server.
77  } else if ((peer->getRole() == HAConfig::PeerConfig::SECONDARY) ||
78  (peer->getRole() == HAConfig::PeerConfig::STANDBY)) {
79  peers_.push_back(peer);
80 
81  // If this is a secondary server, we're in the load balancing
82  // mode, in which case we have two active servers.
83  if (peer->getRole() == HAConfig::PeerConfig::SECONDARY) {
85  }
86 
87  // If this is neither primary nor secondary/standby, it is a backup.
88  } else {
89  backup_peers.push_back(peer);
90  }
91  }
92 
93  // Append backup servers to the list.
94  if (!backup_peers.empty()) {
95  peers_.insert(peers_.end(), backup_peers.begin(), backup_peers.end());
96  }
97 
98  // The query filter is initially setup to serve default scopes, i.e. for the
99  // load balancing case the primary and secondary are responsible for their
100  // own scopes. The backup servers are not responding to any queries. In the
101  // hot standby mode, the primary server is responsible for the entire traffic.
102  // The standby server is not responding.
104 }
105 
106 void
107 QueryFilter::serveScope(const std::string& scope_name) {
108  if (MultiThreadingMgr::instance().getMode()) {
109  std::lock_guard<std::mutex> lock(*mutex_);
110  serveScopeInternal(scope_name);
111  } else {
112  serveScopeInternal(scope_name);
113  }
114 }
115 
116 void
117 QueryFilter::serveScopeInternal(const std::string& scope_name) {
118  validateScopeName(scope_name);
119  scopes_[scope_name] = true;
120 }
121 
122 void
123 QueryFilter::serveScopeOnly(const std::string& scope_name) {
124  if (MultiThreadingMgr::instance().getMode()) {
125  std::lock_guard<std::mutex> lock(*mutex_);
126  serveScopeOnlyInternal(scope_name);
127  } else {
128  serveScopeOnlyInternal(scope_name);
129  }
130 }
131 
132 void
133 QueryFilter::serveScopeOnlyInternal(const std::string& scope_name) {
134  validateScopeName(scope_name);
135  serveNoScopesInternal();
136  serveScopeInternal(scope_name);
137 }
138 
139 void
140 QueryFilter::serveScopes(const std::vector<std::string>& scopes) {
141  if (MultiThreadingMgr::instance().getMode()) {
142  std::lock_guard<std::mutex> lock(*mutex_);
143  serveScopesInternal(scopes);
144  } else {
145  serveScopesInternal(scopes);
146  }
147 }
148 
149 void
150 QueryFilter::serveScopesInternal(const std::vector<std::string>& scopes) {
151  // Remember currently enabled scopes in case we fail to process
152  // the provided list of scopes.
153  auto current_scopes = scopes_;
154  try {
155  serveNoScopesInternal();
156  for (size_t i = 0; i < scopes.size(); ++i) {
157  serveScopeInternal(scopes[i]);
158  }
159 
160  } catch (...) {
161  // There was an error processing scopes list. Need to revert
162  // to the previous configuration.
163  scopes_ = current_scopes;
164  throw;
165  }
166 }
167 
168 void
170  if (MultiThreadingMgr::instance().getMode()) {
171  std::lock_guard<std::mutex> lock(*mutex_);
172  serveDefaultScopesInternal();
173  } else {
174  serveDefaultScopesInternal();
175  }
176 }
177 
178 void
179 QueryFilter::serveDefaultScopesInternal() {
180  // Get this server instance configuration.
181  HAConfig::PeerConfigPtr my_config = config_->getThisServerConfig();
182  HAConfig::PeerConfig::Role my_role = my_config->getRole();
183 
184  // Clear scopes.
185  serveNoScopesInternal();
186 
187  // If I am primary or secondary, then I am only responsible for my own
188  // scope. If I am standby, I am not responsible for any scope.
189  if ((my_role == HAConfig::PeerConfig::PRIMARY) ||
190  (my_role == HAConfig::PeerConfig::SECONDARY)) {
191  serveScopeInternal(my_config->getName());
192  }
193 }
194 
195 void
197  if (MultiThreadingMgr::instance().getMode()) {
198  std::lock_guard<std::mutex> lock(*mutex_);
199  serveFailoverScopesInternal();
200  } else {
201  serveFailoverScopesInternal();
202  }
203 }
204 
205 void
206 QueryFilter::serveFailoverScopesInternal() {
207  // Clear scopes.
208  serveNoScopesInternal();
209 
210  // Iterate over the roles of all servers to see which scope should
211  // be enabled.
212  for (auto peer = peers_.begin(); peer != peers_.end(); ++peer) {
213  // The scope of the primary server must always be served. If we're
214  // doing load balancing, the scope of the secondary server also
215  // has to be served. Regardless if I am primary or secondary,
216  // I will start serving queries from both scopes. If I am a
217  // standby server, I will start serving the scope of the primary
218  // server.
219  if (((*peer)->getRole() == HAConfig::PeerConfig::PRIMARY) ||
220  ((*peer)->getRole() == HAConfig::PeerConfig::SECONDARY)) {
221  serveScopeInternal((*peer)->getName());
222  }
223  }
224 }
225 
226 void
228  if (MultiThreadingMgr::instance().getMode()) {
229  std::lock_guard<std::mutex> lock(*mutex_);
230  serveNoScopesInternal();
231  } else {
232  serveNoScopesInternal();
233  }
234 }
235 
236 void
237 QueryFilter::serveNoScopesInternal() {
238  scopes_.clear();
239 
240  // Disable scope for each peer in the configuration.
241  for (auto peer = peers_.begin(); peer != peers_.end(); ++peer) {
242  scopes_[(*peer)->getName()] = false;
243  }
244 }
245 
246 bool
247 QueryFilter::amServingScope(const std::string& scope_name) const {
248  if (MultiThreadingMgr::instance().getMode()) {
249  std::lock_guard<std::mutex> lock(*mutex_);
250  return (amServingScopeInternal(scope_name));
251  } else {
252  return (amServingScopeInternal(scope_name));
253  }
254 }
255 
256 bool
257 QueryFilter::amServingScopeInternal(const std::string& scope_name) const {
258  auto scope = scopes_.find(scope_name);
259  return ((scope == scopes_.end()) || (scope->second));
260 }
261 
262 std::set<std::string>
264  if (MultiThreadingMgr::instance().getMode()) {
265  std::lock_guard<std::mutex> lock(*mutex_);
266  return (getServedScopesInternal());
267  } else {
268  return (getServedScopesInternal());
269  }
270 }
271 
272 std::set<std::string>
273 QueryFilter::getServedScopesInternal() const {
274  std::set<std::string> scope_set;
275  for (auto scope : scopes_) {
276  if (scope.second) {
277  scope_set.insert(scope.first);
278  }
279  }
280  return (scope_set);
281 }
282 
283 bool
284 QueryFilter::inScope(const dhcp::Pkt4Ptr& query4, std::string& scope_class) const {
285  if (MultiThreadingMgr::instance().getMode()) {
286  std::lock_guard<std::mutex> lock(*mutex_);
287  return (inScopeInternal(query4, scope_class));
288  } else {
289  return (inScopeInternal(query4, scope_class));
290  }
291 }
292 
293 bool
294 QueryFilter::inScope(const dhcp::Pkt6Ptr& query6, std::string& scope_class) const {
295  if (MultiThreadingMgr::instance().getMode()) {
296  std::lock_guard<std::mutex> lock(*mutex_);
297  return (inScopeInternal(query6, scope_class));
298  } else {
299  return (inScopeInternal(query6, scope_class));
300  }
301 }
302 
303 template<typename QueryPtrType>
304 bool
305 QueryFilter::inScopeInternal(const QueryPtrType& query,
306  std::string& scope_class) const {
307  if (!query) {
308  isc_throw(BadValue, "query must not be null");
309  }
310 
311  int candidate_server = 0;
312 
313  // If we're doing load balancing we have to check if this query
314  // belongs to us or the partner. If it belongs to a partner but
315  // we're configured to serve this scope, we should accept it.
316  if (config_->getHAMode() == HAConfig::LOAD_BALANCING) {
317  candidate_server = loadBalance(query);
318  // Malformed query received.
319  if (candidate_server < 0) {
320  return (false);
321  }
322  }
323 
324  auto scope = peers_[candidate_server]->getName();
325  scope_class = makeScopeClass(scope);
326  return ((candidate_server >= 0) && amServingScopeInternal(scope));
327 }
328 
329 int
331  uint8_t lb_hash = 0;
332  // Try to compute the hash by client identifier if the client
333  // identifier has been specified.
334  OptionPtr opt_client_id = query4->getOption(DHO_DHCP_CLIENT_IDENTIFIER);
335  if (opt_client_id && !opt_client_id->getData().empty()) {
336  const auto& client_id_key = opt_client_id->getData();
337  lb_hash = loadBalanceHash(&client_id_key[0], client_id_key.size());
338 
339  } else {
340  // No client identifier available. Use the HW address instead.
341  HWAddrPtr hwaddr = query4->getHWAddr();
342  if (hwaddr && !hwaddr->hwaddr_.empty()) {
343  lb_hash = loadBalanceHash(&hwaddr->hwaddr_[0], hwaddr->hwaddr_.size());
344 
345  } else {
346  // No client identifier and no HW address. Indicate an
347  // error.
348  std::stringstream xid;
349  xid << "0x" << std::hex << query4->getTransid() << std::dec;
351  .arg(xid.str());
352  return (-1);
353  }
354  }
355 
356  // The hash value modulo number of active servers gives an index
357  // of the server to process the packet.
358  return (active_servers_ > 0 ? static_cast<int>(lb_hash % active_servers_) : -1);
359 }
360 
361 int
363  uint8_t lb_hash = 0;
364  // Compute the hash by DUID if the DUID.
365  OptionPtr opt_duid = query6->getOption(D6O_CLIENTID);
366  if (opt_duid && !opt_duid->getData().empty()) {
367  const auto& duid_key = opt_duid->getData();
368  lb_hash = loadBalanceHash(&duid_key[0], duid_key.size());
369 
370  } else {
371  // No DUID. Indicate an error.
372  std::stringstream xid;
373  xid << "0x" << std::hex << query6->getTransid() << std::dec;
375  .arg(xid.str());
376  return (-1);
377  }
378 
379  // The hash value modulo number of active servers gives an index
380  // of the server to process the packet.
381  return (active_servers_ > 0 ? static_cast<int>(lb_hash % active_servers_) : -1);
382 }
383 
384 uint8_t
385 QueryFilter::loadBalanceHash(const uint8_t* key, const size_t key_len) const {
386  uint8_t hash = static_cast<uint8_t>(key_len);
387 
388  for (auto i = key_len; i > 0;) {
389  hash = loadb_mx_tbl[hash ^ key[--i]];
390  }
391 
392  return (hash);
393 }
394 
395 void
396 QueryFilter::validateScopeName(const std::string& scope_name) const {
397  try {
398  // If there is no such server, the scope name is invalid.
399  static_cast<void>(config_->getPeerConfig(scope_name));
400 
401  } catch (...) {
402  isc_throw(BadValue, "invalid server name specified '" << scope_name
403  << "' while enabling/disabling HA scopes");
404  }
405 }
406 
407 std::string
408 QueryFilter::makeScopeClass(const std::string& scope_name) const {
409  return (std::string("HA_") + scope_name);
410 }
411 
412 } // end of namespace isc::ha
413 } // end of namespace isc
void serveScope(const std::string &scope_name)
Enable scope.
void validateScopeName(const std::string &scope_name) const
Checks if the scope name matches a name of any of the configured servers.
const int DBGLVL_TRACE_BASIC
Trace basic operations.
Definition: log_dbglevels.h:69
void serveNoScopes()
Disables all scopes.
std::map< std::string, PeerConfigPtr > PeerConfigMap
Map of the servers&#39; configurations.
Definition: ha_config.h:232
boost::shared_ptr< HWAddr > HWAddrPtr
Shared pointer to a hardware address structure.
Definition: hwaddr.h:154
boost::shared_ptr< Option > OptionPtr
Definition: option.h:36
STL namespace.
bool amServingScope(const std::string &scope_name) const
Checks if this server instance is configured to process traffic belonging to a particular scope...
std::vector< HAConfig::PeerConfigPtr > peers_
Vector of HA peers configurations.
Definition: query_filter.h:329
void serveDefaultScopes()
Serve default scopes for the given HA mode.
#define isc_throw(type, stream)
A shortcut macro to insert known values into exception arguments.
A generic exception that is thrown if a parameter given to a method is considered invalid in that con...
boost::shared_ptr< Pkt6 > Pkt6Ptr
A pointer to Pkt6 packet.
Definition: pkt6.h:28
std::map< std::string, bool > scopes_
Holds mapping of the scope names to the flag which indicates if the scopes are enabled or disabled...
Definition: query_filter.h:333
Definition: edns.h:19
std::set< std::string > getServedScopes() const
Returns served scopes.
void serveScopes(const std::vector< std::string > &scopes)
Enables selected scopes.
boost::scoped_ptr< std::mutex > mutex_
Mutex to protect the internal state.
Definition: query_filter.h:339
std::string makeScopeClass(const std::string &scope_name) const
Returns scope class name for the specified scope name.
boost::shared_ptr< Pkt4 > Pkt4Ptr
A pointer to Pkt4 object.
Definition: pkt4.h:544
int loadBalance(const dhcp::Pkt4Ptr &query4) const
Performs load balancing of the DHCPv4 queries.
void serveFailoverScopes()
Enable scopes required in failover case.
const isc::log::MessageID HA_LOAD_BALANCING_DUID_MISSING
Definition: ha_messages.h:73
Defines the logger used by the top-level component of kea-lfc.
HAConfigPtr config_
Pointer to the HA configuration.
Definition: query_filter.h:326
#define LOG_DEBUG(LOGGER, LEVEL, MESSAGE)
Macro to conveniently test debug output and log it.
Definition: macros.h:14
void serveScopeOnly(const std::string &scope_name)
Enable scope and disable all other scopes.
isc::log::Logger ha_logger("ha-hooks")
Definition: ha_log.h:17
bool inScope(const dhcp::Pkt4Ptr &query4, std::string &scope_class) const
Checks if this server should process the DHCPv4 query.
Role
Server&#39;s role in the High Availability setup.
Definition: ha_config.h:70
uint8_t loadBalanceHash(const uint8_t *key, const size_t key_len) const
Compute load balancing hash.
const isc::log::MessageID HA_LOAD_BALANCING_IDENTIFIER_MISSING
Definition: ha_messages.h:74
int active_servers_
Number of the active servers in the given HA mode.
Definition: query_filter.h:336
boost::shared_ptr< HAConfig > HAConfigPtr
Pointer to the High Availability configuration structure.
Definition: ha_config.h:786
boost::shared_ptr< PeerConfig > PeerConfigPtr
Pointer to the server&#39;s configuration.
Definition: ha_config.h:229