/usr/lib/ipsec/look is in libreswan 3.23-4.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112  | #! /bin/sh
# quick look at current connections and related information
# Copyright (C) 1998, 1999  Henry Spencer.
# Copyright (C) 2012  Paul Wouters
# Copyright (C) 2015 Tuomo Soini <tis@foobar.fi>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# for more details.
#
LC_ALL=C
export LC_ALL
me="ipsec look"
case "$1" in
    --help)
	echo "Usage: ipsec look"
	exit 0
	;;
    --version)
	echo "$me $IPSEC_VERSION"
	exit 0
	;;
esac
# label it just to be sure
echo "$(hostname) $(date)"
# combine spigrp and eroute
for file in /proc/net/ipsec_spigrp /proc/net/ipsec_eroute ; do
    [ -f ${file} ] && cat ${file}
done | awk '
		function pad(subnet) {
			sub("/:", "..", subnet)
			split(subnet, d, ".")
			return sprintf("%03s%03s%03s%03s%03s%04s", d[1], d[2],
							d[3], d[4], d[5], d[6])
		}
		$2 == "->" {
			printf "%s~%-18s -> %-18s => %s\n",
				(pad($1) pad($3)),
				$1, $3, (($5 in tun) ? tun[$5] : $5)
			next
		}
		$3 == "->" {
			printf "%s~%-18s -> %-18s => %s (%s)\n",
				(pad($2) pad($4)),
				$2, $4, (($6 in tun) ? tun[$6] : $6), $1
			next
		}
		{ tun[$1] = $0 }
	' | sort | sed 's/^[^~]*~//'
# tncfg (mostly as a divider line)
if [ -f /proc/net/ipsec_tncfg ]; then
    egrep -v 'NULL[ \t]+mtu=0\(0\)[ \t]+->[ \t]+0' /proc/net/ipsec_tncfg | \
	paste -d % | sed 's/%/   /g' | sed 's/ -> /->/g'
fi
# SAs
if [ -f /proc/net/ipsec_spi ]; then
    sort /proc/net/ipsec_spi
fi
# xfrm for netkey
if [ -f /proc/net/pfkey ]; then
    echo "XFRM state:"
    ip xfrm state
    echo "XFRM policy:"
    ip -o xfrm policy |grep -v "socket" | sort | tr '\\' '\012' | sed '/^\s*$/d'
    echo "XFRM done"
fi
echo IPSEC mangle TABLES
if grep -q ^mangle /proc/net/ip_tables_names 2>/dev/null; then
    iptables -n -t mangle -L IPSEC
fi
if grep -q ^mangle /proc/net/ip6_tables_names 2>/dev/null; then
    ip6tables -n -t mangle -L IPSEC
fi
echo NEW_IPSEC_CONN mangle TABLES
if grep -q ^mangle /proc/net/ip_tables_names 2>/dev/null; then
	iptables -n -t mangle -L NEW_IPSEC_CONN
fi
if grep -q ^mangle /proc/net/ip6_tables_names 2>/dev/null; then
	ip6tables -n -t mangle -L NEW_IPSEC_CONN
fi
echo ROUTING TABLES
ip -4 route
ip -6 route
if [ -f /var/lib/ipsec/nss/cert9.db ]; then
    echo NSS_CERTIFICATES
    certutil -L -d sql:/var/lib/ipsec/nss | head -4
    certutil -L -d sql:/var/lib/ipsec/nss | \
	egrep -v '^NSS_CERTIFICATES|^$|Trust Attributes|MIME,' | LC_ALL=C sort
elif [ -f /var/lib/ipsec/nss/cert8.db ]; then
    echo NSS_CERTIFICATES
    certutil -L -d /var/lib/ipsec/nss | head -4
    certutil -L -d /var/lib/ipsec/nss | \
	egrep -v '^NSS_CERTIFICATES|^$|Trust Attributes|MIME,' | LC_ALL=C sort
fi
 |