Generate BIRD constants with ping statistics in 10s

generate_ptp_cost.sh

#!/bin/sh

# gathering all interfaces with IPv6 link-local address
for with_ll in $(cat /proc/net/if_inet6 | grep "^fe80" | tr -s ' ' | cut -d ' ' -f 6 | sort -u); do
	# POINTOPOINT flag is 1 << 4, filter non-PTP interfaces out
	if [ $(expr \( $(($(cat /sys/class/net/$with_ll/flags))) / 16 \) % 2) -ne 1 ]; then
		continue
	fi
	cost=65535
	ping_rtt=N/A
	ping_result=$(ping -q -L -n -i 1 -c 10 -W 10 ff02::1%$with_ll)
	ping_loss=$(echo "$ping_result" | grep -oP '\d+(?=% packet loss)')
	if [ $ping_loss -ne 100 ]; then
		ping_rtt=$(echo "$ping_result" | tail -1 | cut -d ' ' -f 4 | cut -d '/' -f 2)
		cost=$(echo | awk '{ printf "%0.0f\n", ('$ping_rtt' * 100 / (100 - '$ping_loss') * 10); }')
	fi
	echo 'define PTP_IF_COST__'$(printf $with_ll | tr -c [:alnum:] _ | tr [a-z] [A-Z])' = '$cost'; # loss '$ping_loss'%, rtt '$ping_rtt'ms'
done