1 files changed, 147 insertions, 0 deletions
diff --git a/src/lib/dhcpsrv/ncr_generator.cc b/src/lib/dhcpsrv/ncr_generator.cc
new file mode 100644
index 0000000..bcb8011
--- /dev/null
+++ b/src/lib/dhcpsrv/ncr_generator.cc
@@ -0,0 +1,147 @@
+// Copyright (C) 2015-2020 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 <dhcp/option_data_types.h>
+#include <dhcpsrv/cfgmgr.h>
+#include <dhcpsrv/dhcpsrv_log.h>
+#include <dhcpsrv/d2_client_mgr.h>
+#include <dhcpsrv/ncr_generator.h>
+#include <stdint.h>
+#include <vector>
+
+using namespace isc;
+using namespace isc::dhcp;
+using namespace isc::dhcp_ddns;
+
+namespace {
+
+/// @brief Sends name change request to D2 using lease information.
+///
+/// This method is exception safe.
+///
+/// @param lease Pointer to a lease for which NCR should be sent.
+/// @param identifier Identifier to be used to generate DHCID for
+/// the DNS update. For DHCPv4 it will be hardware address or client
+/// identifier. For DHCPv6 it will be a DUID.
+/// @param label Client identification information in the textual format.
+/// This is used for logging purposes.
+/// @param use_conflict_resolution flag that tells D2 whether or not to
+/// use conflict resolution.
+///
+/// @tparam LeasePtrType Pointer to a lease.
+/// @tparam IdentifierType HW Address, Client Identifier or DUID.
+template<typename LeasePtrType, typename IdentifierType>
+void queueNCRCommon(const NameChangeType& chg_type, const LeasePtrType& lease,
+                    const IdentifierType& identifier, const std::string& label,
+                    const bool use_conflict_resolution = true) {
+
+    // Check if there is a need for update.
+    if (lease->hostname_.empty() || (!lease->fqdn_fwd_ && !lease->fqdn_rev_)
+        || !CfgMgr::instance().getD2ClientMgr().ddnsEnabled()) {
+        LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_TRACE_DETAIL,
+                  DHCPSRV_QUEUE_NCR_SKIP)
+            .arg(label)
+            .arg(lease->addr_.toText());
+
+        return;
+    }
+
+    try {
+        // Create DHCID
+        std::vector<uint8_t> hostname_wire;
+        OptionDataTypeUtil::writeFqdn(lease->hostname_, hostname_wire, true);
+        D2Dhcid dhcid = D2Dhcid(identifier, hostname_wire);
+
+        // Calculate the TTL based on lease life time.
+        uint32_t ttl = calculateDdnsTtl(lease->valid_lft_);
+
+        // Create name change request.
+        NameChangeRequestPtr ncr
+            (new NameChangeRequest(chg_type, lease->fqdn_fwd_, lease->fqdn_rev_,
+                                   lease->hostname_, lease->addr_.toText(),
+                                   dhcid, lease->cltt_ + ttl,
+                                   ttl, use_conflict_resolution));
+
+        LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_TRACE_DETAIL_DATA, DHCPSRV_QUEUE_NCR)
+            .arg(label)
+            .arg(chg_type == CHG_ADD ? "add" : "remove")
+            .arg(ncr->toText());
+
+        // Send name change request.
+        CfgMgr::instance().getD2ClientMgr().sendRequest(ncr);
+
+    } catch (const std::exception& ex) {
+        LOG_ERROR(dhcpsrv_logger, DHCPSRV_QUEUE_NCR_FAILED)
+            .arg(label)
+            .arg(chg_type == CHG_ADD ? "add" : "remove")
+            .arg(lease->addr_.toText())
+            .arg(ex.what());
+    }
+}
+
+} // end of anonymous namespace
+
+namespace isc {
+namespace dhcp {
+
+void queueNCR(const NameChangeType& chg_type, const Lease4Ptr& lease) {
+    if (lease) {
+        // Figure out from the lease's subnet if we should use conflict resolution.
+        // If there's no subnet, something hinky is going on so we'll set it true.
+        bool use_cr = true;
+        Subnet4Ptr subnet = CfgMgr::instance().getCurrentCfg()
+                            ->getCfgSubnets4()->getSubnet(lease->subnet_id_);
+        if (subnet) {
+            // We should always have subnet.
+            use_cr = subnet->getDdnsUseConflictResolution();
+        }
+
+        // Client id takes precedence over HW address.
+        if (lease->client_id_) {
+            queueNCRCommon(chg_type, lease, lease->client_id_->getClientId(),
+                           Pkt4::makeLabel(lease->hwaddr_, lease->client_id_), use_cr);
+
+        } else {
+            // Client id is not specified for the lease. Use HW address
+            // instead.
+            queueNCRCommon(chg_type, lease, lease->hwaddr_,
+                           Pkt4::makeLabel(lease->hwaddr_, lease->client_id_), use_cr);
+        }
+    }
+}
+
+void queueNCR(const NameChangeType& chg_type, const Lease6Ptr& lease) {
+    // DUID is required to generate NCR.
+    if (lease && (lease->type_ != Lease::TYPE_PD) && lease->duid_) {
+        // Figure out from the lease's subnet if we should use conflict resolution.
+        // If there's no subnet, something hinky is going on so we'll set it true.
+        bool use_cr = true;
+        Subnet6Ptr subnet = CfgMgr::instance().getCurrentCfg()
+                            ->getCfgSubnets6()->getSubnet(lease->subnet_id_);
+        if (subnet) {
+            // We should always have subnet.
+            use_cr = subnet->getDdnsUseConflictResolution();
+        }
+
+        queueNCRCommon(chg_type, lease, *(lease->duid_),
+                       Pkt6::makeLabel(lease->duid_, lease->hwaddr_), use_cr);
+    }
+}
+
+uint32_t calculateDdnsTtl(uint32_t lease_lft) {
+    // Per RFC 4702 DDNS RR TTL should be given by:
+    // ((lease life time / 3) < 10 minutes) ? 10 minutes : (lease life time / 3)
+    if (lease_lft < 1800) {
+        return (600);
+    }
+
+    return (lease_lft / 3);
+}
+
+}
+}