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// Copyright (C) 2018-2022 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 <dhcpsrv/sanity_checker.h>
#include <dhcpsrv/cfg_consistency.h>
#include <dhcpsrv/cfgmgr.h>
#include <dhcpsrv/subnet_id.h>
#include <dhcpsrv/dhcpsrv_log.h>
#include <sstream>
namespace isc {
namespace dhcp {
bool SanityChecker::leaseCheckingEnabled(bool current) {
SrvConfigPtr cfg;
if (current) {
cfg = CfgMgr::instance().getCurrentCfg();
} else {
cfg = CfgMgr::instance().getStagingCfg();
}
if (cfg) {
CfgConsistencyPtr sanity = cfg->getConsistency();
return (sanity && (sanity->getLeaseSanityCheck() != CfgConsistency::LEASE_CHECK_NONE));
}
return (false);
}
void SanityChecker::checkLease(Lease4Ptr& lease, bool current) {
SrvConfigPtr cfg;
if (current) {
cfg = CfgMgr::instance().getCurrentCfg();
} else {
cfg = CfgMgr::instance().getStagingCfg();
}
CfgConsistencyPtr sanity = cfg->getConsistency();
if (sanity->getLeaseSanityCheck() == CfgConsistency::LEASE_CHECK_NONE) {
// No sense going farther.
return;
}
CfgSubnets4Ptr subnets = cfg->getCfgSubnets4();
checkLeaseInternal(lease, sanity, subnets);
}
void SanityChecker::checkLease(Lease6Ptr& lease, bool current) {
// We only check IA_NAs currently.
if (lease->type_ != Lease::TYPE_NA) {
return;
}
SrvConfigPtr cfg;
if (current) {
cfg = CfgMgr::instance().getCurrentCfg();
} else {
cfg = CfgMgr::instance().getStagingCfg();
}
CfgConsistencyPtr sanity = cfg->getConsistency();
if (sanity->getLeaseSanityCheck() == CfgConsistency::LEASE_CHECK_NONE) {
// No sense going farther.
return;
}
CfgSubnets6Ptr subnets = cfg->getCfgSubnets6();
checkLeaseInternal(lease, sanity, subnets);
}
template<typename LeasePtrType, typename SubnetsType>
void SanityChecker::checkLeaseInternal(LeasePtrType& lease, const CfgConsistencyPtr& checks,
const SubnetsType& subnets) {
auto subnet = subnets->getBySubnetId(lease->subnet_id_);
if (subnet && subnet->inRange(lease->addr_)) {
// If the subnet is defined and the address is in range, we're good.
return;
}
// Ok, if we got here, that means that either we did not find a subnet
// of found it, but it wasn't the right subnet.
SubnetID id = findSubnetId(lease, subnets);
// Prepare a message in the case the check fails.
std::ostringstream msg;
if (id != 0) {
msg << "the lease should have subnet-id " << id;
} else {
msg << "the lease IP address did not belong to a configured subnet";
}
switch (checks->getLeaseSanityCheck()) {
case CfgConsistency::LEASE_CHECK_WARN:
if (lease->subnet_id_ != id) {
// Print a warning, but return the lease as is.
LOG_WARN(dhcpsrv_logger, DHCPSRV_LEASE_SANITY_FAIL)
.arg(lease->addr_.toText())
.arg(lease->subnet_id_)
.arg(msg.str());
}
break;
case CfgConsistency::LEASE_CHECK_FIX:
if (lease->subnet_id_ != id) {
// If there is a better subnet, use it.
if (id != 0) {
LOG_INFO(dhcpsrv_logger, DHCPSRV_LEASE_SANITY_FIXED)
.arg(lease->addr_.toText())
.arg(lease->subnet_id_)
.arg(id);
lease->subnet_id_ = id;
} else {
// If not, return the lease as is.
LOG_WARN(dhcpsrv_logger, DHCPSRV_LEASE_SANITY_FAIL)
.arg(lease->addr_.toText())
.arg(lease->subnet_id_)
.arg(msg.str());
}
}
break;
case CfgConsistency::LEASE_CHECK_FIX_DEL:
if (lease->subnet_id_ != id) {
// If there is a better subnet, use it.
if (id != 0) {
LOG_INFO(dhcpsrv_logger, DHCPSRV_LEASE_SANITY_FIXED)
.arg(lease->addr_.toText())
.arg(lease->subnet_id_)
.arg(id);
lease->subnet_id_ = id;
break;
} else {
// If not, delete the lease.
LOG_INFO(dhcpsrv_logger, DHCPSRV_LEASE_SANITY_FAIL_DISCARD)
.arg(lease->addr_.toText())
.arg(lease->subnet_id_)
.arg(msg.str());
lease.reset();
}
}
break;
case CfgConsistency::LEASE_CHECK_DEL:
if (lease->subnet_id_ != id) {
LOG_INFO(dhcpsrv_logger, DHCPSRV_LEASE_SANITY_FAIL_DISCARD)
.arg(lease->addr_.toText())
.arg(lease->subnet_id_)
.arg(msg.str());
lease.reset();
}
break;
default:
// Shouldn't get here but some compilers and analyzers
// complain. We'll we treat it as NONE and return the
// lease as-is.
break;
}
// Additional checks may be implemented in the future here.
/// @todo: add a check if the address is within specified dynamic pool
/// if not, check if the address is reserved.
}
template<typename LeaseType, typename SubnetsType>
SubnetID SanityChecker::findSubnetId(const LeaseType& lease, const SubnetsType& subnets) {
auto subnet = subnets->selectSubnet(lease->addr_);
if (!subnet) {
return (0);
}
return (subnet->getID());
}
}
}
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