1#!/bin/bash
2# Copyright 2021 Google LLC
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#      http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15
16# Every 30 seconds, send out an RA so that the kernel will receive a response.
17# This ensures that all BMCs (even ones that think they are routers) get updated
18# information from the other systems on the network.
19w=30
20while true; do
21  start=$SECONDS
22  rdisc6 -m gbmcbr -r 1 -w $(( w * 1000 )) >/dev/null 2>/dev/null
23  # If rdisc6 exits early we still want to wait the full `w` time before
24  # starting again.
25  (( timeout = start + w - SECONDS ))
26  sleep $(( timeout < 0 ? 0 : timeout ))
27done
28