IPv6 Segment Routing (SRv6)

https://skjune12.hatenadiary.com/entry/2017/12/16/223455

#!/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 link set veth-h1-rt1 up
    run ip netns exec host1 ip -6 route add fc00:12::/64 via fc00:a::1
    run ip netns exec host1 ip -6 route add fc00:23::/64 via fc00:a::1
    run ip netns exec host1 ip -6 route add fc00:b::/64 via fc00:a::1
    run ip netns exec host1 ip -6 route add fc00:c::/64 via fc00:a::1

    # router1 configuration
    run ip netns exec router1 ip link set lo up
    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

    # 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
}

create_router2 () {
    # setup namespaces
    run ip netns add node1
    run ip netns add node2
    run ip netns add router2

    # setup veth peer
    run ip link add veth-node1-rt2 type veth peer name veth-rt2-node1
    run ip link set veth-node1-rt2 netns node1
    run ip link set veth-rt2-node1 netns router2

    run ip link add veth-node2-rt2 type veth peer name veth-rt2-node2
    run ip link set veth-node2-rt2 netns node2
    run ip link set veth-rt2-node2 netns router2

    # node1 configuraiton
    run ip netns exec node1 ip link set lo up
    run ip netns exec node1 ip addr add fc00:b::10/64 dev veth-node1-rt2
    run ip netns exec node1 ip link set veth-node1-rt2 up
    run ip netns exec node1 ip -6 route add fc00:12::/64 via fc00:b::1
    run ip netns exec node1 ip -6 route add fc00:23::/64 via fc00:b::1
    run ip netns exec node1 ip -6 route add fc00:a::/64 via fc00:b::1
    run ip netns exec node1 ip -6 route add fc00:c::/64 via fc00:b::1

    # node2 configuraiton
    run ip netns exec node2 ip link set lo up
    run ip netns exec node2 ip addr add fc00:b::20/64 dev veth-node2-rt2
    run ip netns exec node2 ip link set veth-node2-rt2 up
    run ip netns exec node2 ip -6 route add fc00:12::/64 via fc00:b::1
    run ip netns exec node2 ip -6 route add fc00:23::/64 via fc00:b::1
    run ip netns exec node2 ip -6 route add fc00:a::/64 via fc00:b::1
    run ip netns exec node2 ip -6 route add fc00:c::/64 via fc00:b::1

    # router2 configuration
    run ip netns exec router2 ip link set lo up
    run ip netns exec router2 ip link set veth-rt2-node1 up
    run ip netns exec router2 ip link set veth-rt2-node2 up
    run ip netns exec router2 ip link add hostbr0 type bridge
    run ip netns exec router2 ip link set hostbr0 up
    run ip netns exec router2 ip link set dev veth-rt2-node1 master hostbr0
    run ip netns exec router2 ip link set dev veth-rt2-node2 master hostbr0
    run ip netns exec router2 ip addr add fc00:b::1/64 dev hostbr0

    # 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

    # seg6_enable for node1 and node2
    ip netns exec node1 sysctl net.ipv6.conf.all.forwarding=1
    ip netns exec node1 sysctl net.ipv6.conf.all.seg6_enabled=1
    ip netns exec node1 sysctl net.ipv6.conf.veth-node1-rt2.seg6_enabled=1

    ip netns exec node2 sysctl net.ipv6.conf.all.forwarding=1
    ip netns exec node2 sysctl net.ipv6.conf.all.seg6_enabled=1
    ip netns exec node2 sysctl net.ipv6.conf.veth-node2-rt2.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 link set veth-h2-rt3 up
    run ip netns exec host2 ip -6 route add fc00:12::/64 via fc00:c::1
    run ip netns exec host2 ip -6 route add fc00:23::/64 via fc00:c::1
    run ip netns exec host2 ip -6 route add fc00:a::/64 via fc00:c::1
    run ip netns exec host2 ip -6 route add fc00:b::/64 via fc00:c::1

    # router3 configuration
    run ip netns exec router3 ip link set lo up
    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

    # 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
}

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
    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:b::/64 via fc00:12::2
    run ip netns exec router1 ip -6 route add fc00:c::/64 via fc00:12::2
    run ip netns exec router1 ip -6 route add fc00:23::/64 via fc00:12::2

    # configure router2
    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:a::/64 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
    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:c::/64 via fc00:23::2

    # configure router3
    run ip netns exec router3 ip link set veth-rt3-rt2 up
    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:b::/64 via fc00:23::1
    run ip netns exec router3 ip -6 route add fc00:a::/64 via fc00:23::1
    run ip netns exec router3 ip -6 route add fc00:12::/64 via fc00:23::1
}

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

    run ip netns del router2
    run ip netns del node1
    run ip netns del node2

    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