meta-google: Netboot: Provide command to trigger dhcp

Installer needs to trigger dhcp process when
netboot starts. Currently it just powercycles
the machine, which is not efficient.
This provides a script that installer can
invoke without powercycle machine.

Tested: tested manually on the machine and
verified that dhcp has started.

Change-Id: I6e596e3695f88543ad864eb431587a5f974f81b4
Signed-off-by: Yuxiao Zhang <yuxiaozhang@google.com>
diff --git a/meta-google/recipes-google/networking/gbmc-bridge/gbmc-start-dhcp.sh b/meta-google/recipes-google/networking/gbmc-bridge/gbmc-start-dhcp.sh
new file mode 100644
index 0000000..d90b724
--- /dev/null
+++ b/meta-google/recipes-google/networking/gbmc-bridge/gbmc-start-dhcp.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# stop dhcp term service to prevent race condition
+systemctl is-active --quiet gbmc-br-dhcp-term && systemctl stop gbmc-br-dhcp-term
+
+# start the dhcp service
+systemctl start gbmc-br-dhcp