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Add retry mechanism to get_ipv4_addr#1621

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Add retry mechanism to get_ipv4_addr #1621

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18 changes: 17 additions & 1 deletion modules/test/base/bin/get_ipv4_addr
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Original file line numberDiff line numberDiff line change
Expand Up@@ -17,6 +17,22 @@
NET=$1
MAC=$2

IP_ADDR=$(nmap -sP $NET | grep -B 2 $MAC | head -n 1 | cut -d " " -f 5)
# Some devices intermittently do not answer a given ARP request, so a single
# nmap sweep can miss a device that is in fact present. Retry the sweep a few
# times (each retry issues fresh ARP requests) before giving up, so one dropped
# reply does not cause resolution to fail.
RETRIES=4
RETRY_DELAY=2

IP_ADDR=""
for attempt in $(seq 1 "$RETRIES"); do
IP_ADDR=$(nmap -sP $NET | grep -B 2 $MAC | head -n 1 | cut -d " " -f 5)
if [ -n "$IP_ADDR" ]; then
break
fi
if [ "$attempt" -lt "$RETRIES" ]; then
sleep "$RETRY_DELAY"
fi
done

echo $IP_ADDR
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