[#1418] Checkpoint: preparation code done

8 files changed, 112 insertions, 21 deletions

diff --git a/src/bin/dhcp4/dhcp4_messages.cc b/src/bin/dhcp4/dhcp4_messages.cc
index df37920301..8124fb9d18 100644
--- a/src/bin/dhcp4/dhcp4_messages.cc
+++ b/src/bin/dhcp4/dhcp4_messages.cc
@@ -84,6 +84,7 @@ extern const isc::log::MessageID DHCP4_INIT_FAIL = "DHCP4_INIT_FAIL";
 extern const isc::log::MessageID DHCP4_INIT_REBOOT = "DHCP4_INIT_REBOOT";
 extern const isc::log::MessageID DHCP4_LEASE_ADVERT = "DHCP4_LEASE_ADVERT";
 extern const isc::log::MessageID DHCP4_LEASE_ALLOC = "DHCP4_LEASE_ALLOC";
+extern const isc::log::MessageID DHCP4_LEASE_REUSE = "DHCP4_LEASE_REUSE";
 extern const isc::log::MessageID DHCP4_MULTI_THREADING_INFO = "DHCP4_MULTI_THREADING_INFO";
 extern const isc::log::MessageID DHCP4_NCR_CREATE = "DHCP4_NCR_CREATE";
 extern const isc::log::MessageID DHCP4_NCR_CREATION_FAILED = "DHCP4_NCR_CREATION_FAILED";
@@ -236,6 +237,7 @@ const char* values[] = {
     "DHCP4_INIT_REBOOT", "%1: client is in INIT-REBOOT state and requests address %2",
     "DHCP4_LEASE_ADVERT", "%1: lease %2 will be advertised",
     "DHCP4_LEASE_ALLOC", "%1: lease %2 has been allocated for %3 seconds",
+    "DHCP4_LEASE_REUSE", "%1: lease %2 has been reused for %3 seconds",
     "DHCP4_MULTI_THREADING_INFO", "enabled: %1, number of threads: %2, queue size: %3",
     "DHCP4_NCR_CREATE", "%1: DDNS updates enabled, therefore sending name change requests",
     "DHCP4_NCR_CREATION_FAILED", "%1: failed to generate name change requests for DNS: %2",
diff --git a/src/bin/dhcp4/dhcp4_messages.h b/src/bin/dhcp4/dhcp4_messages.h
index 70e914145f..8d561bfbab 100644
--- a/src/bin/dhcp4/dhcp4_messages.h
+++ b/src/bin/dhcp4/dhcp4_messages.h
@@ -85,6 +85,7 @@ extern const isc::log::MessageID DHCP4_INIT_FAIL;
 extern const isc::log::MessageID DHCP4_INIT_REBOOT;
 extern const isc::log::MessageID DHCP4_LEASE_ADVERT;
 extern const isc::log::MessageID DHCP4_LEASE_ALLOC;
+extern const isc::log::MessageID DHCP4_LEASE_REUSE;
 extern const isc::log::MessageID DHCP4_MULTI_THREADING_INFO;
 extern const isc::log::MessageID DHCP4_NCR_CREATE;
 extern const isc::log::MessageID DHCP4_NCR_CREATION_FAILED;
diff --git a/src/bin/dhcp4/dhcp4_messages.mes b/src/bin/dhcp4/dhcp4_messages.mes
index daaa60dfb2..9749a67908 100644
--- a/src/bin/dhcp4/dhcp4_messages.mes
+++ b/src/bin/dhcp4/dhcp4_messages.mes
@@ -456,6 +456,14 @@ client and the transaction identification information. The second argument
 contains the allocated IPv4 address. The third argument is the validity
 lifetime.
 
+% DHCP4_LEASE_REUSE %1: lease %2 has been reused for %3 seconds
+This informational message indicates that the server successfully reused a
+lease in response to client's message. The lease information will
+be sent to the client in the DHCPACK message. The first argument contains the
+client and the transaction identification information. The second argument
+contains the allocated IPv4 address. The third argument is the validity
+lifetime.
+
 % DHCP4_MULTI_THREADING_INFO enabled: %1, number of threads: %2, queue size: %3
 This is a message listing some information about the multi-threading parameters
 with which the server is running.
diff --git a/src/bin/dhcp4/dhcp4_srv.cc b/src/bin/dhcp4/dhcp4_srv.cc
index 8a59716582..4739e88446 100644
--- a/src/bin/dhcp4/dhcp4_srv.cc
+++ b/src/bin/dhcp4/dhcp4_srv.cc
@@ -1354,7 +1354,7 @@ Dhcpv4Srv::processDhcp4Query(Pkt4Ptr& query, Pkt4Ptr& rsp,
         callout_handle->setArgument("query4", query);
 
         Lease4CollectionPtr new_leases(new Lease4Collection());
-        if (ctx->new_lease_) {
+        if (ctx->new_lease_ && (ctx->new_lease_->remaining_valid_lft_ == 0)) {
             new_leases->push_back(ctx->new_lease_);
         }
         callout_handle->setArgument("leases4", new_leases);
@@ -2508,6 +2508,15 @@ Dhcpv4Srv::assignLease(Dhcpv4Exchange& ex) {
         // switched to a different subnet within a shared network.
         postAllocateNameUpdate(ctx, lease, query, resp, client_name_changed);
 
+        // Reuse the lease if possible.
+        if (lease->remaining_valid_lft_ > 0) {
+            lease->valid_lft_ = lease->remaining_valid_lft_;
+            LOG_INFO(lease4_logger, DHCP4_LEASE_REUSE)
+                .arg(query->getLabel())
+                .arg(lease->addr_.toText())
+                .arg(Lease::lifetimeToText(lease->valid_lft_));
+        }
+
         // IP Address Lease time (type 51)
         OptionPtr opt(new OptionUint32(Option::V4, DHO_DHCP_LEASE_TIME,
                                        lease->valid_lft_));
@@ -2592,6 +2601,9 @@ Dhcpv4Srv::postAllocateNameUpdate(const AllocEngine::ClientContext4Ptr& ctx, con
         // implementation) and log an error.
         try {
             if (!ctx->fake_allocation_) {
+                // The lease can't be reused.
+                lease->remaining_valid_lft_ = 0;
+
                 // The lease update should be safe, because the lease should
                 // be already in the database. In most cases the exception
                 // would be thrown if the lease was missing.
diff --git a/src/bin/dhcp6/dhcp6_messages.cc b/src/bin/dhcp6/dhcp6_messages.cc
index 3696558256..db95d640dd 100644
--- a/src/bin/dhcp6/dhcp6_messages.cc
+++ b/src/bin/dhcp6/dhcp6_messages.cc
@@ -86,6 +86,7 @@ extern const isc::log::MessageID DHCP6_LEASE_DATA = "DHCP6_LEASE_DATA";
 extern const isc::log::MessageID DHCP6_LEASE_NA_WITHOUT_DUID = "DHCP6_LEASE_NA_WITHOUT_DUID";
 extern const isc::log::MessageID DHCP6_LEASE_PD_WITHOUT_DUID = "DHCP6_LEASE_PD_WITHOUT_DUID";
 extern const isc::log::MessageID DHCP6_LEASE_RENEW = "DHCP6_LEASE_RENEW";
+extern const isc::log::MessageID DHCP6_LEASE_REUSE = "DHCP6_LEASE_REUSE";
 extern const isc::log::MessageID DHCP6_MULTI_THREADING_INFO = "DHCP6_MULTI_THREADING_INFO";
 extern const isc::log::MessageID DHCP6_NOT_RUNNING = "DHCP6_NOT_RUNNING";
 extern const isc::log::MessageID DHCP6_NO_INTERFACES = "DHCP6_NO_INTERFACES";
@@ -117,6 +118,7 @@ extern const isc::log::MessageID DHCP6_PD_LEASE_ADVERT_FAIL = "DHCP6_PD_LEASE_AD
 extern const isc::log::MessageID DHCP6_PD_LEASE_ALLOC = "DHCP6_PD_LEASE_ALLOC";
 extern const isc::log::MessageID DHCP6_PD_LEASE_ALLOC_FAIL = "DHCP6_PD_LEASE_ALLOC_FAIL";
 extern const isc::log::MessageID DHCP6_PD_LEASE_RENEW = "DHCP6_PD_LEASE_RENEW";
+extern const isc::log::MessageID DHCP6_PD_LEASE_REUSE = "DHCP6_PD_LEASE_REUSE";
 extern const isc::log::MessageID DHCP6_PROCESS_IA_NA_EXTEND = "DHCP6_PROCESS_IA_NA_EXTEND";
 extern const isc::log::MessageID DHCP6_PROCESS_IA_NA_RELEASE = "DHCP6_PROCESS_IA_NA_RELEASE";
 extern const isc::log::MessageID DHCP6_PROCESS_IA_NA_REQUEST = "DHCP6_PROCESS_IA_NA_REQUEST";
@@ -238,6 +240,7 @@ const char* values[] = {
     "DHCP6_LEASE_NA_WITHOUT_DUID", "%1: address lease for address %2 does not have a DUID",
     "DHCP6_LEASE_PD_WITHOUT_DUID", "%1: lease for prefix %2/%3 does not have a DUID",
     "DHCP6_LEASE_RENEW", "%1: lease for address %2 and iaid=%3 has been allocated",
+    "DHCP6_LEASE_REUSE", "%1: lease for address %2 and iaid=%3 has been reused for %4 seconds",
     "DHCP6_MULTI_THREADING_INFO", "enabled: %1, number of threads: %2, queue size: %3",
     "DHCP6_NOT_RUNNING", "IPv6 DHCP server is not running",
     "DHCP6_NO_INTERFACES", "failed to detect any network interfaces",
@@ -269,6 +272,7 @@ const char* values[] = {
     "DHCP6_PD_LEASE_ALLOC", "%1: lease for prefix %2/%3 and iaid=%4 has been allocated for %5 seconds",
     "DHCP6_PD_LEASE_ALLOC_FAIL", "%1: failed to grant a prefix lease for iaid=%2",
     "DHCP6_PD_LEASE_RENEW", "%1: lease for prefix %2/%3 and iaid=%4 has been allocated",
+    "DHCP6_PD_LEASE_REUSE", "%1: lease for prefix %2/%3 and iaid=%4 has been reused for %5 seconds",
     "DHCP6_PROCESS_IA_NA_EXTEND", "%1: extending lease lifetime for IA_NA option with iaid=%2",
     "DHCP6_PROCESS_IA_NA_RELEASE", "%1: releasing lease for IA_NA option with iaid=%2",
     "DHCP6_PROCESS_IA_NA_REQUEST", "%1: server is processing IA_NA option with iaid=%2 and hint=%3",
diff --git a/src/bin/dhcp6/dhcp6_messages.h b/src/bin/dhcp6/dhcp6_messages.h
index e30330bfef..6207fead91 100644
--- a/src/bin/dhcp6/dhcp6_messages.h
+++ b/src/bin/dhcp6/dhcp6_messages.h
@@ -87,6 +87,7 @@ extern const isc::log::MessageID DHCP6_LEASE_DATA;
 extern const isc::log::MessageID DHCP6_LEASE_NA_WITHOUT_DUID;
 extern const isc::log::MessageID DHCP6_LEASE_PD_WITHOUT_DUID;
 extern const isc::log::MessageID DHCP6_LEASE_RENEW;
+extern const isc::log::MessageID DHCP6_LEASE_REUSE;
 extern const isc::log::MessageID DHCP6_MULTI_THREADING_INFO;
 extern const isc::log::MessageID DHCP6_NOT_RUNNING;
 extern const isc::log::MessageID DHCP6_NO_INTERFACES;
@@ -118,6 +119,7 @@ extern const isc::log::MessageID DHCP6_PD_LEASE_ADVERT_FAIL;
 extern const isc::log::MessageID DHCP6_PD_LEASE_ALLOC;
 extern const isc::log::MessageID DHCP6_PD_LEASE_ALLOC_FAIL;
 extern const isc::log::MessageID DHCP6_PD_LEASE_RENEW;
+extern const isc::log::MessageID DHCP6_PD_LEASE_REUSE;
 extern const isc::log::MessageID DHCP6_PROCESS_IA_NA_EXTEND;
 extern const isc::log::MessageID DHCP6_PROCESS_IA_NA_RELEASE;
 extern const isc::log::MessageID DHCP6_PROCESS_IA_NA_REQUEST;
diff --git a/src/bin/dhcp6/dhcp6_messages.mes b/src/bin/dhcp6/dhcp6_messages.mes
index 5ffc80dca2..567ba5dbe2 100644
--- a/src/bin/dhcp6/dhcp6_messages.mes
+++ b/src/bin/dhcp6/dhcp6_messages.mes
@@ -503,6 +503,14 @@ The first argument includes the client and transaction identification
 information. The remaining arguments hold the allocated address and
 IAID.
 
+% DHCP6_LEASE_REUSE %1: lease for address %2 and iaid=%3 has been reused for %4 seconds
+This informational message indicates that in response to a client's
+message, the server successfully reused a non-temporary address
+lease. This is a normal behavior and indicates successful operation.
+The first argument includes the client and transaction identification
+information. The remaining arguments hold the allocated address,
+IAID and validity lifetime.
+
 % DHCP6_MULTI_THREADING_INFO enabled: %1, number of threads: %2, queue size: %3
 This is a message listing some information about the multi-threading parameters
 with which the server is running.
@@ -684,6 +692,14 @@ The first argument includes the client and transaction identification
 information. The remaining arguments hold the allocated prefix,
 prefix length and IAID.
 
+% DHCP6_PD_LEASE_REUSE %1: lease for prefix %2/%3 and iaid=%4 has been reused for %5 seconds
+This informational message indicates that in response to a client's
+message, the server successfully reused a prefix lease.
+This is a normal behavior and indicates successful operation.
+The first argument includes the client and transaction identification
+information. The remaining arguments hold the allocated prefix,
+prefix length, IAID and validity lifetime.
+
 % DHCP6_PROCESS_IA_NA_EXTEND %1: extending lease lifetime for IA_NA option with iaid=%2
 This message is logged when the server is starting to extend the lifetime
 of the address lease associated with the particular IAID. The first argument
diff --git a/src/bin/dhcp6/dhcp6_srv.cc b/src/bin/dhcp6/dhcp6_srv.cc
index 38f4687e16..656d291c04 100644
--- a/src/bin/dhcp6/dhcp6_srv.cc
+++ b/src/bin/dhcp6/dhcp6_srv.cc
@@ -1004,8 +1004,11 @@ Dhcpv6Srv::processDhcp6Query(Pkt6Ptr& query, Pkt6Ptr& rsp) {
 
         Lease6CollectionPtr new_leases(new Lease6Collection());
         if (!ctx.new_leases_.empty()) {
-            new_leases->assign(ctx.new_leases_.cbegin(),
-                               ctx.new_leases_.cend());
+            for (auto new_lease : ctx.new_leases_) {
+                if (new_lease->remaining_valid_lft_ == 0) {
+                    new_leases->push_back(new_lease);
+                }
+            }
         }
         callout_handle->setArgument("leases6", new_leases);
 
@@ -2062,12 +2065,21 @@ Dhcpv6Srv::assignIA_NA(const Pkt6Ptr& query, const Pkt6Ptr& answer,
                 .arg(query->getLabel())
                 .arg(lease->addr_.toText())
                 .arg(ia->getIAID());
-        } else {
+        } else if (lease->remaining_valid_lft_ == 0) {
             LOG_INFO(lease6_logger, DHCP6_LEASE_ALLOC)
                 .arg(query->getLabel())
                 .arg(lease->addr_.toText())
                 .arg(ia->getIAID())
                 .arg(Lease::lifetimeToText(lease->valid_lft_));
+        } else {
+            auto age = lease->valid_lft_ - lease->remaining_valid_lft_;
+            lease->valid_lft_ = lease->remaining_valid_lft_;
+            lease->preferred_lft_ -= age;
+            LOG_INFO(lease6_logger, DHCP6_LEASE_REUSE)
+                .arg(query->getLabel())
+                .arg(lease->addr_.toText())
+                .arg(ia->getIAID())
+                .arg(Lease::lifetimeToText(lease->valid_lft_));
         }
         LOG_DEBUG(lease6_logger, DBG_DHCP6_DETAIL_DATA, DHCP6_LEASE_DATA)
             .arg(query->getLabel())
@@ -2170,11 +2182,6 @@ Dhcpv6Srv::assignIA_PD(const Pkt6Ptr& query, const Pkt6Ptr& /*answer*/,
         for (Lease6Collection::iterator l = leases.begin();
              l != leases.end(); ++l) {
 
-            // Check for new minimum lease time
-            if (((*l)->preferred_lft_ > 0) && (min_preferred_lft > (*l)->preferred_lft_)) {
-                min_preferred_lft = (*l)->preferred_lft_;
-            }
-
             // We have a lease! Let's wrap its content into IA_PD option
             // with IAADDR suboption.
             if (ctx.fake_allocation_) {
@@ -2183,13 +2190,28 @@ Dhcpv6Srv::assignIA_PD(const Pkt6Ptr& query, const Pkt6Ptr& /*answer*/,
                     .arg((*l)->addr_.toText())
                     .arg(static_cast<int>((*l)->prefixlen_))
                     .arg(ia->getIAID());
-            } else {
+            } else if ((*l)->remaining_valid_lft_ == 0) {
                 LOG_INFO(lease6_logger, DHCP6_PD_LEASE_ALLOC)
                     .arg(query->getLabel())
                     .arg((*l)->addr_.toText())
                     .arg(static_cast<int>((*l)->prefixlen_))
                     .arg(ia->getIAID())
                     .arg(Lease::lifetimeToText((*l)->valid_lft_));
+            } else {
+                auto age = (*l)->valid_lft_ - (*l)->remaining_valid_lft_;
+                (*l)->valid_lft_ = (*l)->remaining_valid_lft_;
+                (*l)->preferred_lft_ -= age;
+                LOG_INFO(lease6_logger, DHCP6_PD_LEASE_REUSE)
+                    .arg(query->getLabel())
+                    .arg((*l)->addr_.toText())
+                    .arg(static_cast<int>((*l)->prefixlen_))
+                    .arg(ia->getIAID())
+                    .arg(Lease::lifetimeToText((*l)->valid_lft_));
+            }
+
+            // Check for new minimum lease time
+            if (((*l)->preferred_lft_ > 0) && (min_preferred_lft > (*l)->preferred_lft_)) {
+                min_preferred_lft = (*l)->preferred_lft_;
             }
 
             boost::shared_ptr<Option6IAPrefix>
@@ -2329,16 +2351,27 @@ Dhcpv6Srv::extendIA_NA(const Pkt6Ptr& query, const Pkt6Ptr& answer,
                                 (*l)->addr_, (*l)->preferred_lft_, (*l)->valid_lft_));
         ia_rsp->addOption(iaaddr);
 
+        if ((*l)->remaining_valid_lft_ == 0) {
+            LOG_INFO(lease6_logger, DHCP6_LEASE_RENEW)
+                .arg(query->getLabel())
+                .arg((*l)->addr_.toText())
+                .arg(ia->getIAID());
+        } else {
+            auto age = (*l)->valid_lft_ - (*l)->remaining_valid_lft_;
+            (*l)->valid_lft_ = (*l)->remaining_valid_lft_;
+            (*l)->preferred_lft_ -= age;
+            LOG_INFO(lease6_logger, DHCP6_LEASE_REUSE)
+                .arg(query->getLabel())
+                .arg((*l)->addr_.toText())
+                .arg(ia->getIAID())
+                .arg(Lease::lifetimeToText((*l)->valid_lft_));
+        }
+
         // Check for new minimum lease time
         if (((*l)->preferred_lft_ > 0) && (min_preferred_lft > (*l)->preferred_lft_)) {
             min_preferred_lft = (*l)->preferred_lft_;
         }
 
-        LOG_INFO(lease6_logger, DHCP6_LEASE_RENEW)
-            .arg(query->getLabel())
-            .arg((*l)->addr_.toText())
-            .arg(ia->getIAID());
-
         // Now remove this prefix from the hints list.
         AllocEngine::Resource hint_type((*l)->addr_, (*l)->prefixlen_);
         hints.erase(std::remove(hints.begin(), hints.end(), hint_type),
@@ -2523,17 +2556,29 @@ Dhcpv6Srv::extendIA_PD(const Pkt6Ptr& query,
             }
         }
 
+        if ((*l)->remaining_valid_lft_ == 0) {
+            LOG_INFO(lease6_logger, DHCP6_PD_LEASE_RENEW)
+                .arg(query->getLabel())
+                .arg((*l)->addr_.toText())
+                .arg(static_cast<int>((*l)->prefixlen_))
+                .arg(ia->getIAID());
+        } else {
+            auto age = (*l)->valid_lft_ - (*l)->remaining_valid_lft_;
+            (*l)->valid_lft_ = (*l)->remaining_valid_lft_;
+            (*l)->preferred_lft_ -= age;
+            LOG_INFO(lease6_logger, DHCP6_PD_LEASE_REUSE)
+                .arg(query->getLabel())
+                .arg((*l)->addr_.toText())
+                .arg(static_cast<int>((*l)->prefixlen_))
+                .arg(ia->getIAID())
+                .arg(Lease::lifetimeToText((*l)->valid_lft_));
+        }
+
         // Check for new minimum lease time
         if (((*l)->preferred_lft_ > 0) && ((*l)->preferred_lft_ < min_preferred_lft)) {
             min_preferred_lft = (*l)->preferred_lft_;
         }
 
-        LOG_INFO(lease6_logger, DHCP6_PD_LEASE_RENEW)
-            .arg(query->getLabel())
-            .arg((*l)->addr_.toText())
-            .arg(static_cast<int>((*l)->prefixlen_))
-            .arg(ia->getIAID());
-
         // Now remove this prefix from the hints list.
         AllocEngine::Resource hint_type((*l)->addr_, (*l)->prefixlen_);
         hints.erase(std::remove(hints.begin(), hints.end(), hint_type),
@@ -4290,6 +4335,7 @@ Dhcpv6Srv::checkDynamicSubnetChange(const Pkt6Ptr& question, Pkt6Ptr& answer,
             (*l)->hostname_ = ctx.hostname_;
             (*l)->fqdn_fwd_ = ctx.fwd_dns_update_;
             (*l)->fqdn_rev_ = ctx.rev_dns_update_;
+            (*l)->remaining_valid_lft_ = 0;
             LeaseMgrFactory::instance().updateLease6(*l);
         }
     }