[3677] HR implemented for lease6 renewals

src/lib/dhcpsrv/alloc_engine.cc

@@ -672,15 +672,22 @@ AllocEngine::allocateReservedLeases6(ClientContext6& ctx, Lease6Collection& exis
 
         // If there's a lease for this address, let's not create it.
         // It doesn't matter whether it is for this client or for someone else.
-        if (LeaseMgrFactory::instance().getLease6(ctx.type_, addr)) {
-            continue;
-        }
+        if (!LeaseMgrFactory::instance().getLease6(ctx.type_, addr)) {
+            // Ok, let's create a new lease...
+            Lease6Ptr lease = createLease6(ctx, addr, prefix_len);
 
-        // Ok, let's create a new lease...
-        Lease6Ptr lease = createLease6(ctx, addr, prefix_len);
+            // ... and add it to the existing leases list.
+            existing_leases.push_back(lease);
 
-        // ... and add it to the existing leases list.
-        existing_leases.push_back(lease);
+            if (ctx.type_ == Lease::TYPE_NA) {
+                LOG_INFO(dhcpsrv_logger, DHCPSRV_HR_RESERVED_ADDR_GRANTED)
+                    .arg(addr.toText()).arg(ctx.duid_->toText());
+            } else {
+                LOG_INFO(dhcpsrv_logger, DHCPSRV_HR_RESERVED_PREFIX_GRANTED)
+                    .arg(addr.toText()).arg(static_cast<int>(prefix_len))
+                    .arg(ctx.duid_->toText());
+            }
+        }
     }
 }
 
@@ -1639,38 +1646,33 @@ AllocEngine::renewLeases6(ClientContext6& ctx) {
 
             ctx.host_ = HostMgr::instance().get6(ctx.subnet_->getID(), ctx.duid_,
                                                  ctx.hwaddr_);
+        } else {
+            // Host reservations disabled? Then explicitly set host to NULL
+            ctx.host_.reset();
         }
 
         // Check if there are any leases for this client.
         Lease6Collection leases = LeaseMgrFactory::instance()
             .getLeases6(ctx.type_, *ctx.duid_, ctx.iaid_, ctx.subnet_->getID());
 
-        // Now we have 3 lists:
-        // 1. what client requested (ctx.hints_)
-        // 2. what leases we currently have (leases)
-        // 3. reservation list: ctx.hosts_->getIPv6Reservations(TYPE_NA)
+        if (!leases.empty()) {
+            // Check if the existing leases are reserved for someone else.
+            // If they're not, we're ok to keep using them.
+            removeNonmatchingReservedLeases6(ctx, leases);
+        }
 
-        // The behavior here is similar to how we process requests, but
-        // there are noticable differences.
+        if (ctx.host_) {
+            // If we have host reservation, allocate those leases.
+            allocateReservedLeases6(ctx, leases);
 
-        // Now do the checks:
-        // Case 1. if there are no leases, and there are reservations...
-        //   1.1. are the reserved addresses are used by someone else?
-        //       yes: we have a problem
-        //       no: assign them => done
-        // Case 2. if there are leases and there are no reservations...
-        //   2.1 are the leases reserved for someone else?
-        //       yes: release them, assign something else
-        //       no: renew them => done
-        // Case 3. if there are leases and there are reservations...
-        //   3.1 are the leases matching reservations?
-        //       yes: renew them => done
-        //       no: release existing leases, assign new ones based on reservations
-        // Case 4/catch-all. if there are no leases and no reservations...
-        //       assign new leases
-        //
+            // There's one more check to do. Let's remove leases that are not
+            // matching reservations, i.e. if client X has address A, but there's
+            // a reservation for address B, we should release A and reassign B.
+            // Caveat: do this only if we have at least one reserved address.
+            removeNonreservedLeases6(ctx, leases);
+        }
 
-        // Extend all existing leases.
+        // Extend all existing leases that passed all checks.
         for (Lease6Collection::iterator l = leases.begin(); l != leases.end(); ++l) {
             extendLease6(ctx, *l);
         }

src/lib/dhcpsrv/dhcpsrv_messages.mes

@@ -215,6 +215,16 @@ hook point sets the skip flag. It means that the server was told that
 no lease6 should be assigned. The server will not put that lease in its
 database and the client will get a NoAddrsAvail for that IA_NA option.
 
+% DHCPSRV_HR_RESERVED_ADDR_GRANTED Reserved address %1 was was assigned to client (duid=%2)
+This informational message singals that there is a reservation for this client
+and this client got this specific address. This is normal operation for
+host reservation.
+
+% DHCPSRV_HR_RESERVED_PREFIX_GRANTED Reserved prefix %1/%2 was was assigned to client (duid=%3)
+This informational message singals that there is a reservation for this client
+and this client got this specific prefix. This is normal operation for
+host reservation.
+
 % DHCPSRV_INVALID_ACCESS invalid database access string: %1
 This is logged when an attempt has been made to parse a database access string
 and the attempt ended in error.  The access string in question - which