Add internalapi routes for scenario A adoption

Doing data-plane adoption while testing scenario A (different
subnets between wallaby and next-gen) will result in connectivity
problem since pods will try to reach old CP using default route
(since both CP are on different subnets) and won't be able to reach it.

Adding this route in internalapi to support data-plane
adoption scenario A gates.

Currently only one route can be added, if needed logic can be improved
to include more than one route.

Ref: OSPRH-5602

Author: averdagu

Makefile

@@ -46,6 +46,7 @@ CLEANUP_DIR_CMD					 ?= rm -Rf
 # be also cloned from OPENSTACK_REPO/OPENSTACK_BRANCH.
 CHECKOUT_FROM_OPENSTACK_REF	?= false
 
+NETWORK_INTERNALAPI_ROUTE 	?=
 NETWORK_INTERNALAPI_ADDRESS_PREFIX 	?= 172.17.0
 NETWORK_STORAGE_ADDRESS_PREFIX 	?= 172.18.0
 NETWORK_TENANT_ADDRESS_PREFIX 	?= 172.19.0
@@ -2308,6 +2309,7 @@ nncp_with_retries: ## Deploy NNCP with retries
 nncp: export INTERFACE=${NNCP_INTERFACE}
 nncp: export BRIDGE_NAME=${NNCP_BRIDGE}
 nncp: export INTERNALAPI_PREFIX=${NETWORK_INTERNALAPI_ADDRESS_PREFIX}
+nncp: export INTERNALAPI_ROUTE=${NETWORK_INTERNALAPI_ROUTE}
 nncp: export NNCP_INTERNALAPI_HOST_ROUTES=${INTERNALAPI_HOST_ROUTES}
 nncp: export STORAGE_PREFIX=${NETWORK_STORAGE_ADDRESS_PREFIX}
 nncp: export NNCP_STORAGE_HOST_ROUTES=${STORAGE_HOST_ROUTES}

scripts/gen-netatt.sh

@@ -122,6 +122,18 @@ if [ -n "$IPV4_ENABLED" ]; then
         "range_start": "${INTERNALAPI_PREFIX}.30",
         "range_end": "${INTERNALAPI_PREFIX}.70"
 EOF_CAT
+    # In the data-plane adoption scenario A (where different IP subnet ranges
+    # between next-gen and wallaby are used) the net-attach-def needs additional routes.
+    # The 172.17.1 is a hardcoded IP used on all scenario A gates.
+    if [ -n "$INTERNALAPI_ROUTE" ]; then
+    cat >> ${DEPLOY_DIR}/internalapi.yaml <<EOF_CAT
+        "routes": [
+          {
+             "dst": "${INTERNALAPI_ROUTE}"
+          }
+        ]
+EOF_CAT
+    fi
 elif [ -n "$IPV6_ENABLED" ]; then
     cat >> ${DEPLOY_DIR}/internalapi.yaml <<EOF_CAT
         "range": "fd00:bbbb::/64",