ss.sh

#!/bin/sh

. ~/.bin/mylib.sh

require_commands netstat

IPV4ADDR_REGEX='((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)'

IPV6ADDR_REGEX='((([0-9a-f]{1,4}:){7}([0-9a-f]{1,4}|:))|(([0-9a-f]{1,4}:){6}(:[0-9a-f]{1,4}|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9a-f]{1,4}:){5}(((:[0-9a-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9a-f]{1,4}:){4}(((:[0-9a-f]{1,4}){1,3})|((:[0-9a-f]{1,4})?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9a-f]{1,4}:){3}(((:[0-9a-f]{1,4}){1,4})|((:[0-9a-f]{1,4}){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9a-f]{1,4}:){2}(((:[0-9a-f]{1,4}){1,5})|((:[0-9a-f]{1,4}){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9a-f]{1,4}:){1}(((:[0-9a-f]{1,4}){1,6})|((:[0-9a-f]{1,4}){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:[0-9a-f]{1,4}){1,7})|((:[0-9a-f]{1,4}){0,5}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))(%.+)?\s*'

print_line_help() {
	cat <<-EOF
		Usage: `basename "$0"` [OPTIONS]

		Linux's ss like command implemeted with BSD netstat.
	EOF
}

print_long_help() {
	print_line_help
	cat <<-EOF
	EOF
}


with_lsof() {
	echo "Proto Recv-Q Send-Q  Local Address          Foreign Address        (state))"
	if [ "$lsof" == "true" ]; then
		# remove header lines
		awk 'NR>2 { print }' |
		while read line; do
			proto="`
				echo "$line" |
					awk '{ print $1 }' |
					sed -E 's/(tcp|udp)4?6?/\1/'
			`"
			version="`
				echo "$line" |
					awk '{ print $1 }' |
					sed -E 's/(tcp|udp)(4?6?)/\2/' |
					head -c1
			`"
			addr="`
				echo "$line" |
					awk '{ print $4 }' |
					# surround with []. eg. ::1 -> [::1]
					sed -E 's/('"${IPV6ADDR_REGEX}"')\./@[\1]:/; s/('"${IPV4ADDR_REGEX}"')\./@\1:/; s/^\*\./:/; s/(.*)\.([0-9]+)$/@\1:\2/;'
			`"

			if echo "$proto" | grep -s "tcp|udp"; then
				echo "$line"
				continue;
			fi

			result="`lsof -i "$version$proto$addr" +c0 | awk 'NR>1{ print $1"("$2")" }'`"

			echo "$line\t$result"
		done
	else
		cat
	fi
}

lsof="false"
options=""
sed="p;"

while getopts "46alnptu" opt; do
	case "$opt" in
		"4")
			options="${options} -f inet"
			;;
		"6")
			options="${options} -f inet6"
			;;
		"a")
			options="${options} -a"
			;;
		"l")
			options="${options} -a"
			sed="${sed#"p;"} 1,2p; /LISTEN/p;"
			;;
		"n")
			options="${options} -n"
			;;
		"p")
			lsof="true"
			;;
		"t")
			options="${options} -p tcp"
			;;
		"u")
			options="${options} -p udp"
			;;
		*)
			eecho "not supported; $opt"
			print_line_help
			exit 2
			;;
	esac
done

netstat ${options} | sed -n "${sed}" |
	with_lsof