From 5699d84ac019eef6e1ede51cf3435b67951388aa Mon Sep 17 00:00:00 2001
From: Matthew Slowe <foo@mafoo.org.uk>
Date: Sat, 3 May 2025 11:40:49 +0100
Subject: [PATCH] import

---
 network-watchdog.sh | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 network-watchdog.sh

diff --git a/network-watchdog.sh b/network-watchdog.sh
new file mode 100644
index 0000000..a5aa1a6
--- /dev/null
+++ b/network-watchdog.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+
+USAGE="Usage: $0 <check target> [ <grace time seconds> ]"
+
+TAG=network-watchdog
+REMOTE_CHECK=${1:?$USAGE}
+GRACE_TIME=${2:-1800}
+STATE_FILE=${STATE_FILE:-/var/run/$TAG.state}
+
+ping -c 4 -w 5 "${REMOTE_CHECK}" >/dev/null
+if [ $? -ne 0 ]
+then
+	# Failure
+	logger -p local0.alert -t $TAG "Remote host $REMOTE_CHECK is unavailable"
+	if [ ! -r "$STATE_FILE" ]
+	then
+		echo "$REMOTE_CHECK unavailable since $(date -Iseconds)" >"$STATE_FILE"
+		logger -p local0.info -t $TAG "Recorded failure in $STATE_FILE"
+	else
+		STATE_FILE_TS=$(date -r "$STATE_FILE" '+%s')
+		NOW=$(date '+%s')
+		logger -p local0.debug -t $TAG "Checking $STATE_FILE_TS & $NOW = $(( NOW - STATE_FILE_TS )) against gracetime=$GRACE_TIME"
+		if [ "$(( NOW - STATE_FILE_TS ))" -gt "$GRACE_TIME" ]
+		then
+			logger -p local0.crit -t $TAG "Remote host $REMOTE_CHECK has been unavailable for too long -- rebooting"
+			reboot
+		else
+			logger -p local0.notice -t $TAG "Not reached threshold yet"
+		fi
+	fi
+else
+	if [ -r "$STATE_FILE" ]
+	then
+		rm ${STATE_FILE}
+		logger -p local0.notice -t $TAG "Remote host $REMOTE_CHECK back to normal"
+	else
+		logger -p local0.info -t $TAG "Remote host $REMOTE_CHECK all ok"
+	fi
+fi
+