[#2631] Global reserved addresses must be feasible

kea-dhcp<4/6> both now enforce globally reserved addresses
to be within the selected subnet/shared-network

Added a ChangeLog entry

doc/sphinx/arm/dhcp4-srv.rst
doc/sphinx/arm/dhcp6-srv.rst
    Updated global reservation commmentary

src/lib/dhcpsrv/alloc_engine.cc
    AllocEngine::allocateGlobalReservedLeases6() - modified to enforce
    address feasibility/subnet reselect

    AllocEngine::labelNetworkOrSubnet() - new convenience method for logging

    hasAddressReservation() - modified to enforce
    address feasibility/subnet reselect

src/lib/dhcpsrv/alloc_engine_messages.mes
    New log messages:
    ALLOC_ENGINE_IGNORING_UNSUITABLE_GLOBAL_ADDRESS
    ALLOC_ENGINE_IGNORING_UNSUITABLE_GLOBAL_ADDRESS6

src/lib/dhcpsrv/tests/alloc_engine4_unittest.cc
src/lib/dhcpsrv/tests/alloc_engine6_unittest.cc
src/lib/dhcpsrv/tests/alloc_engine_utils.*
src/bin/dhcp4/tests/host_unittest.cc
src/bin/dhcp6/tests/host_unittest.cc
    New and updated tests

1 files changed, 2 insertions, 0 deletions

diff --git a/src/lib/dhcpsrv/alloc_engine_messages.h b/src/lib/dhcpsrv/alloc_engine_messages.h
index d4ce8882ea..866ce92b33 100644
--- a/src/lib/dhcpsrv/alloc_engine_messages.h
+++ b/src/lib/dhcpsrv/alloc_engine_messages.h
@@ -8,6 +8,8 @@
 namespace isc {
 namespace dhcp {
 
+extern const isc::log::MessageID ALLOC_ENGINE_IGNORING_UNSUITABLE_GLOBAL_ADDRESS;
+extern const isc::log::MessageID ALLOC_ENGINE_IGNORING_UNSUITABLE_GLOBAL_ADDRESS6;
 extern const isc::log::MessageID ALLOC_ENGINE_LEASE_RECLAIMED;
 extern const isc::log::MessageID ALLOC_ENGINE_REMOVAL_NCR_FAILED;
 extern const isc::log::MessageID ALLOC_ENGINE_V4_ALLOC_ERROR;