Some really useless script that generates IPv6 hops using netns for your traceroute pleasure.

hops_generate.py

import sys
import itertools

from netaddr import *

PREFIX = IPNetwork('fd00:0:3:1337::/64')
NAME = 'virtual0'
COUNT = 30

UPSTREAM=0
DOWNSTREAM=1

print(f'#!/bin/sh')

subnets = PREFIX.subnet(127)
subnet = next(subnets)
downstreams = [
    subnet[DOWNSTREAM]   
    for subnet in itertools.islice(PREFIX.subnet(127), COUNT)
]

print(f'if [[ "$1" == "setup" ]]; then')
print(f'set -ex')

# Configure a bridge that will connect to everyone
gw_host = subnet[UPSTREAM]
print(f'ip link add {NAME}b0 type bridge')
print(f'ip -6 addr add dev {NAME}b0 {gw_host}/{subnet.prefixlen}')
print(f'ip link set {NAME}b0 up')

for i in range(COUNT):
    # Configure a veth pair for the bridge and the namespace
    print(f'ip link add {NAME}ns{i}br0 type veth peer name {NAME}ns{i}e0')
    print(f'brctl addif {NAME}b0 {NAME}ns{i}br0')
    print(f'ip link set {NAME}ns{i}br0 up')

    # Create a namespace and add one of the veth
    print(f'ip netns add {NAME}ns{i}')
    print(f'ip link set {NAME}ns{i}e0 netns {NAME}ns{i}')
    print(f'ip netns exec {NAME}ns{i} ip link set lo up')

    upstream_host = subnet[UPSTREAM]
    upstream_address = subnet[DOWNSTREAM]
    subnet = next(subnets)
    downstream_address = subnet[UPSTREAM]
    downstream_host = subnet[DOWNSTREAM]

    # Add this namespace addresses
    print(f'ip netns exec {NAME}ns{i} ip -6 addr add dev {NAME}ns{i}e0 {upstream_address}/{subnet.prefixlen}')
    print(f'ip netns exec {NAME}ns{i} ip -6 addr add dev {NAME}ns{i}e0 {downstream_address}/{subnet.prefixlen}')
    print(f'ip netns exec {NAME}ns{i} ip link set {NAME}ns{i}e0 up')

    # Add upstream routes
    print(f'ip netns exec {NAME}ns{i} ip -6 route add ::/0 via {upstream_host}')

    # Add downstream routes
    for j in range(i+1, COUNT):
        downstream_net = downstreams[j]
        print(f'ip netns exec {NAME}ns{i} ip -6 route add {downstream_net}/{subnet.prefixlen} via {downstream_host}')


    # Enable forwarding
    print(f'ip netns exec {NAME}ns{i} sysctl net.ipv6.conf.all.forwarding=1')

# Configure master route
for i in range(1, COUNT):
    downstream_net = downstreams[i]
    print(f'ip -6 route add {downstream_net}/{subnet.prefixlen} via {downstreams[0]}')

print(f'elif [[ "$1" == "teardown" ]]; then')
print(f'set -x')

for i in range(COUNT-1, -1, -1):
    print(f'ip netns delete {NAME}ns{i}')
    print(f'ip link delete {NAME}ns{i}br0')

print(f'ip link delete {NAME}b0 type bridge')

print(f'else')
print('echo "Usage: $0 {setup|teardown}"')

print(f'fi')