Test IPSec between two containers

test-ipsec.sh

#!/bin/bash -ex
# Test IPSec with a tunnel between two containers.

# Provide /proc/net/pfkey since af_key.ko apparently isn't autoloaded.
sudo modprobe af_key

# Start and prepare the containers.
for host in left right
do
        docker run \
            --detach \
            --env=container=docker \
            --{host,}name=$host \
            --privileged \
            --rm \
            --volume=/lib/modules \
            --volume=/dev/null:/dev/tty{1..6}:ro \
            fedora /usr/lib/systemd/systemd 3

        # Install everything useful
        docker exec $host dnf -y install \
            iptables iputils libreswan procps-ng tcpdump which
        docker exec $host dnf clean all

        # Create keys
        docker exec $host ipsec initnss --nssdir /etc/ipsec.d
        docker exec $host ipsec newhostkey --output /etc/ipsec.d/$host.secrets
done

# Write the shared configuration to both containers.
left_ckaid=$(docker exec left ipsec showhostkey --list | sed -n '1s/.* //p')
left_ip=$(docker inspect --format='{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' left)
right_ckaid=$(docker exec right ipsec showhostkey --list | sed -n '1s/.* //p')
right_ip=$(docker inspect --format='{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' right)
cat << EOF |
conn containertunnel
	authby=rsasig
	auto=start
	left=$left_ip
	right=$right_ip
	leftid=@left.example.com
	rightid=@right.example.com
$(docker exec left ipsec showhostkey --left --ckaid $left_ckaid)
$(docker exec right ipsec showhostkey --right --ckaid $right_ckaid)
EOF
tee >/dev/null \
    >(docker exec -i left tee /etc/ipsec.d/left.conf >/dev/null) \
    >(docker exec -i right tee /etc/ipsec.d/right.conf >/dev/null)

# Start the daemon in both containers.
for host in left right ; do docker exec $host systemctl restart ipsec ; done

# Bring up the tunnel on one of them.
docker exec left ipsec auto --add containertunnel || :
sleep 5  # Avoid:  024 need --listen before --initiate
docker exec left ipsec auto --up containertunnel

# Spawn pings on one and watch ESP traffic on the other.
docker exec --detach right ping -c 100 $left_ip
docker exec left tcpdump -ni any esp or udp port 500 or udp port 4500

# Check for errors.
grep -F XfrmInTmplMismatch /proc/net/xfrm_stat

# Clean up.
docker stop left right

Thanks man. This script is awesome! Nice work! You saved me!