1 files changed, 233 insertions, 0 deletions
diff --git a/src/lib/dhcpsrv/cfgmgr.cc b/src/lib/dhcpsrv/cfgmgr.cc
new file mode 100644
index 0000000..c532404
--- /dev/null
+++ b/src/lib/dhcpsrv/cfgmgr.cc
@@ -0,0 +1,233 @@
+// Copyright (C) 2012-2021 Internet Systems Consortium, Inc. ("ISC")
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#include <config.h>
+#include <asiolink/io_address.h>
+#include <dhcp/iface_mgr.h>
+#include <dhcp/libdhcp++.h>
+#include <dhcpsrv/cfgmgr.h>
+#include <dhcpsrv/dhcpsrv_log.h>
+#include <sstream>
+#include <string>
+
+using namespace isc::asiolink;
+using namespace isc::util;
+
+namespace isc {
+namespace dhcp {
+
+const size_t CfgMgr::CONFIG_LIST_SIZE = 10;
+
+CfgMgr&
+CfgMgr::instance() {
+    static CfgMgr cfg_mgr;
+    return (cfg_mgr);
+}
+
+Optional<std::string>
+CfgMgr::getDataDir() const {
+    return (datadir_);
+}
+
+void
+CfgMgr::setDataDir(const std::string& datadir, bool unspecified) {
+    datadir_ = Optional<std::string>(datadir, unspecified);
+}
+
+void
+CfgMgr::setD2ClientConfig(D2ClientConfigPtr& new_config) {
+    ensureCurrentAllocated();
+    // Note that D2ClientMgr::setD2Config() actually attempts to apply the
+    // configuration by stopping its sender and opening a new one and so
+    // forth per the new configuration.
+    d2_client_mgr_.setD2ClientConfig(new_config);
+
+    // Manager will throw if the set fails, if it succeeds
+    // we'll update our SrvConfig, configuration_, with the D2ClientConfig
+    // used. This is largely bookkeeping in case we ever want to compare
+    // configuration_ to another SrvConfig.
+    configuration_->setD2ClientConfig(new_config);
+}
+
+bool
+CfgMgr::ddnsEnabled() {
+    return (d2_client_mgr_.ddnsEnabled());
+}
+
+const D2ClientConfigPtr&
+CfgMgr::getD2ClientConfig() const {
+    return (d2_client_mgr_.getD2ClientConfig());
+}
+
+D2ClientMgr&
+CfgMgr::getD2ClientMgr() {
+    return (d2_client_mgr_);
+}
+
+void
+CfgMgr::ensureCurrentAllocated() {
+    if (!configuration_ || configs_.empty()) {
+        configuration_.reset(new SrvConfig());
+        configs_.push_back(configuration_);
+    }
+}
+
+void
+CfgMgr::clear() {
+    if (configuration_) {
+        configuration_->removeStatistics();
+    }
+    configs_.clear();
+    external_configs_.clear();
+    D2ClientConfigPtr d2_default_conf(new D2ClientConfig());
+    setD2ClientConfig(d2_default_conf);
+}
+
+void
+CfgMgr::commit() {
+    ensureCurrentAllocated();
+
+    // First we need to remove statistics. The new configuration can have fewer
+    // subnets. Also, it may change subnet-ids. So we need to remove them all
+    // and add it back.
+    configuration_->removeStatistics();
+
+    if (!configs_.back()->sequenceEquals(*configuration_)) {
+        configuration_ = configs_.back();
+        // Keep track of the maximum size of the configs history. Before adding
+        // new element, we have to remove the oldest one.
+        if (configs_.size() > CONFIG_LIST_SIZE) {
+            SrvConfigList::iterator it = configs_.begin();
+            std::advance(it, configs_.size() - CONFIG_LIST_SIZE);
+            configs_.erase(configs_.begin(), it);
+        }
+    }
+
+    // Set the last commit timestamp.
+    auto now = boost::posix_time::second_clock::universal_time();
+    configuration_->setLastCommitTime(now);
+
+    // Now we need to set the statistics back.
+    configuration_->updateStatistics();
+
+    configuration_->configureLowerLevelLibraries();
+}
+
+void
+CfgMgr::rollback() {
+    ensureCurrentAllocated();
+    if (!configuration_->sequenceEquals(*configs_.back())) {
+        configs_.pop_back();
+    }
+}
+
+void
+CfgMgr::revert(const size_t index) {
+    ensureCurrentAllocated();
+    if (index == 0) {
+        isc_throw(isc::OutOfRange, "invalid commit index 0 when reverting"
+                  " to an old configuration");
+    } else if (index > configs_.size() - 1) {
+        isc_throw(isc::OutOfRange, "unable to revert to commit index '"
+                  << index << "', only '" << configs_.size() - 1
+                  << "' previous commits available");
+    }
+
+    // Let's rollback an existing configuration to make sure that the last
+    // configuration on the list is the current one. Note that all remaining
+    // operations in this function should be exception free so there shouldn't
+    // be a problem that the revert operation fails and the staging
+    // configuration is destroyed by this rollback.
+    rollback();
+
+    // Get the iterator to the current configuration and then advance to the
+    // desired one.
+    SrvConfigList::const_reverse_iterator it = configs_.rbegin();
+    std::advance(it, index);
+
+    // Copy the desired configuration to the new staging configuration. The
+    // staging configuration is re-created here because we rolled back earlier
+    // in this function.
+    (*it)->copy(*getStagingCfg());
+
+    // Make the staging configuration a current one.
+    commit();
+}
+
+SrvConfigPtr
+CfgMgr::getCurrentCfg() {
+    ensureCurrentAllocated();
+    return (configuration_);
+}
+
+SrvConfigPtr
+CfgMgr::getStagingCfg() {
+    ensureCurrentAllocated();
+    if (configuration_->sequenceEquals(*configs_.back())) {
+        uint32_t sequence = configuration_->getSequence();
+        configs_.push_back(SrvConfigPtr(new SrvConfig(++sequence)));
+    }
+    return (configs_.back());
+}
+
+SrvConfigPtr
+CfgMgr::createExternalCfg() {
+    uint32_t seq = 0;
+
+    if (!external_configs_.empty()) {
+        seq = external_configs_.rbegin()->second->getSequence() + 1;
+    }
+
+    SrvConfigPtr srv_config(new SrvConfig(seq));
+    external_configs_[seq] = srv_config;
+    return (srv_config);
+}
+
+void
+CfgMgr::mergeIntoStagingCfg(const uint32_t seq) {
+    mergeIntoCfg(getStagingCfg(), seq);
+}
+
+void
+CfgMgr::mergeIntoCurrentCfg(const uint32_t seq) {
+    try {
+        // First we need to remove statistics.
+        getCurrentCfg()->removeStatistics();
+        mergeIntoCfg(getCurrentCfg(), seq);
+
+    } catch (...) {
+        // Make sure the statistics is updated even if the merge failed.
+        getCurrentCfg()->updateStatistics();
+        throw;
+    }
+    getCurrentCfg()->updateStatistics();
+}
+
+void
+CfgMgr::mergeIntoCfg(const SrvConfigPtr& target_config, const uint32_t seq) {
+    auto source_config = external_configs_.find(seq);
+    if (source_config != external_configs_.end()) {
+        target_config->merge(*source_config->second);
+        external_configs_.erase(source_config);
+
+    } else {
+        isc_throw(BadValue, "the external configuration with the sequence number "
+                  "of " << seq << " was not found");
+    }
+}
+
+CfgMgr::CfgMgr()
+    : datadir_(DHCP_DATA_DIR, true), d2_client_mgr_(), family_(AF_INET) {
+    // DHCP_DATA_DIR must be set set with -DDHCP_DATA_DIR="..." in Makefile.am
+    // Note: the definition of DHCP_DATA_DIR needs to include quotation marks
+    // See AM_CPPFLAGS definition in Makefile.am
+}
+
+CfgMgr::~CfgMgr() {
+}
+
+} // end of isc::dhcp namespace
+} // end of isc namespace