create-namespaces.sh

# Thanks to https://github.com/skjune12/srv6-playground
#!/bin/bash

if [[ $(id -u) -ne 0 ]] ; then
    echo "Please run with sudo"
    exit 1
fi

run () {
    echo "$@"
    "$@" || exit 1
}

create_router1 () {
    # setup namespaces
    run ip netns add host1
    run ip netns add router1

    # setup veth peer
    run ip link add veth-h1-rt1 type veth peer name veth-rt1-h1
    run ip link set veth-h1-rt1 netns host1
    run ip link set veth-rt1-h1 netns router1

    # host1 configuraiton
    run ip netns exec host1 ip link set lo up
    run ip netns exec host1 ip addr add fc00:a::2/64 dev veth-h1-rt1
    run ip netns exec host1 ip addr add 2001:db8:1::2/64 dev veth-h1-rt1
    run ip netns exec host1 ip link set veth-h1-rt1 up
    run ip netns exec host1 ip -6 route add fc00::1/128 via fc00:a::1
    run ip netns exec host1 ip -6 route add fc00::2/128 via fc00:a::1
    run ip netns exec host1 ip -6 route add fc00::3/128 via fc00:a::1
    run ip netns exec host1 ip -6 route add 2001:db8:2::/64 via fc00:a::1

    # router1 configuration
    run ip netns exec router1 ip link set lo up
    run ip netns exec router1 ip -6 a add fc00::1/128 dev lo
    run ip netns exec router1 ip link set veth-rt1-h1 up
    run ip netns exec router1 ip addr add fc00:a::1/64 dev veth-rt1-h1
    run ip netns exec router1 ip addr add 2001:db8:1::1/64 dev veth-rt1-h1

    # sysctl for router1
    ip netns exec router1 sysctl net.ipv6.conf.all.forwarding=1
    ip netns exec router1 sysctl net.ipv6.conf.all.seg6_enabled=1
    ip netns exec router1 sysctl net.ipv6.conf.veth-rt1-h1.seg6_enabled=1
}

create_router2 () {
    # setup namespaces
    run ip netns add router2

    # router2 configuration
    run ip netns exec router2 ip link set lo up
    run ip netns exec router2 ip -6 a add fc00::2/128 dev lo

    # sysctl for router2
    ip netns exec router2 sysctl net.ipv6.conf.all.forwarding=1
    ip netns exec router2 sysctl net.ipv6.conf.all.seg6_enabled=1
}

create_router3 () {
    # setup namespaces
    run ip netns add host2
    run ip netns add router3

    # setup veth peer
    run ip link add veth-h2-rt3 type veth peer name veth-rt3-h2
    run ip link set veth-h2-rt3 netns host2
    run ip link set veth-rt3-h2 netns router3

    # host2 configuraiton
    run ip netns exec host2 ip link set lo up
    run ip netns exec host2 ip addr add fc00:c::2/64 dev veth-h2-rt3
    run ip netns exec host2 ip addr add 2001:db8:2::2/64 dev veth-h2-rt3
    run ip netns exec host2 ip link set veth-h2-rt3 up
    run ip netns exec host2 ip -6 route add fc00::1/128 via fc00:c::1
    run ip netns exec host2 ip -6 route add fc00::2/128 via fc00:c::1
    run ip netns exec host2 ip -6 route add fc00::3/128 via fc00:c::1
    run ip netns exec host2 ip -6 route add 2001:db8:1::/64 via fc00:c::1

    # router3 configuration
    run ip netns exec router3 ip link set lo up
    run ip netns exec router3 ip -6 a add fc00::3/128 dev lo
    run ip netns exec router3 ip link set veth-rt3-h2 up
    run ip netns exec router3 ip addr add fc00:c::1/64 dev veth-rt3-h2
    run ip netns exec router3 ip addr add 2001:db8:2::1/64 dev veth-rt3-h2

    # sysctl for router3
    ip netns exec router3 sysctl net.ipv6.conf.all.forwarding=1
    ip netns exec router3 sysctl net.ipv6.conf.all.seg6_enabled=1
    ip netns exec router3 sysctl net.ipv6.conf.veth-rt3-h2.seg6_enabled=1
}

connect_rt1_rt2 () {
    # create veth peer
    run ip link add veth-rt1-rt2 type veth peer name veth-rt2-rt1
    run ip link set veth-rt1-rt2 netns router1
    run ip link set veth-rt2-rt1 netns router2

    # configure router1
    ip netns exec router1 sysctl net.ipv6.conf.veth-rt1-rt2.seg6_enabled=1
    run ip netns exec router1 ip link set veth-rt1-rt2 up
    run ip netns exec router1 ip addr add fc00:12::1/64 dev veth-rt1-rt2
    run ip netns exec router1 ip -6 route add fc00::2/128 via fc00:12::2
    run ip netns exec router1 ip -6 route add fc00::3/128 via fc00:12::2

    run ip netns exec router1 ip -6 route add 2001:db8:2::/64 encap seg6 mode encap segs fc00::3 dev veth-rt1-h1

    # configure router2
    ip netns exec router2 sysctl net.ipv6.conf.veth-rt2-rt1.seg6_enabled=1
    run ip netns exec router2 ip link set veth-rt2-rt1 up
    run ip netns exec router2 ip addr add fc00:12::2/64 dev veth-rt2-rt1
    run ip netns exec router2 ip -6 route add fc00::1/128 via fc00:12::1
}

connect_rt2_rt3 () {
    # create veth peer
    run ip link add veth-rt2-rt3 type veth peer name veth-rt3-rt2
    run ip link set veth-rt2-rt3 netns router2
    run ip link set veth-rt3-rt2 netns router3

    # configure router2
    run ip netns exec router2 ip link set veth-rt2-rt3 up
    ip netns exec router2 sysctl net.ipv6.conf.veth-rt2-rt3.seg6_enabled=1
    run ip netns exec router2 ip addr add fc00:23::1/64 dev veth-rt2-rt3
    run ip netns exec router2 ip -6 route add fc00::3/128 via fc00:23::2

    # configure router3
    run ip netns exec router3 ip link set veth-rt3-rt2 up
    ip netns exec router3 sysctl net.ipv6.conf.veth-rt3-rt2.seg6_enabled=1
    run ip netns exec router3 ip addr add fc00:23::2/64 dev veth-rt3-rt2
    run ip netns exec router3 ip -6 route add fc00::1/128 via fc00:23::1
    run ip netns exec router3 ip -6 route add fc00::2/128 via fc00:23::1

    run ip netns exec router3 ip -6 route add 2001:db8:1::/64 encap seg6 mode encap segs fc00::1 dev veth-rt3-h2
}

destroy_network () {
    run ip netns del router1
    run ip netns del host1

    run ip netns del router2

    run ip netns del router3
    run ip netns del host2
}

stop () {
    destroy_network
}

trap stop 0 1 2 3 13 14 15

# exec functions
create_router1
create_router2
create_router3

connect_rt1_rt2
connect_rt2_rt3

status=0; $SHELL || status=$?
exit $status