show-01: basic routing setup

[sorah]

https://scrapbox.io/rknet/show-01
#186

Flow: client netns -> main netns -> (backbone: cs -> (nat44> br, nat64 > br, or br) ) -> main netns -> server netns

main netns performs SNAT from client netns (IPv4 and IPv6 source address randomization) and connects to cs-01, and DNAT to server netns (IPv4 public address conversion and IPv6 destination address randomization).

rk@show-01-venue:~$ sudo ip netns exec showc ping 192.50.220.175
PING 192.50.220.175 (192.50.220.175) 56(84) bytes of data.
64 bytes from 192.50.220.175: icmp_seq=1 ttl=60 time=0.337 ms
^C
--- 192.50.220.175 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.337/0.337/0.337/0.000 ms
rk@show-01-venue:~$ sudo ip netns exec showc ping 2001:df0:8500:ca64:a9:8200:c032:dcaf
PING 2001:df0:8500:ca64:a9:8200:c032:dcaf (2001:df0:8500:ca64:a9:8200:c032:dcaf) 56 data bytes
64 bytes from 2001:df0:8500:ca64:a9:8200:c032:dcaf: icmp_seq=1 ttl=56 time=0.746 ms
^C
--- 2001:df0:8500:ca64:a9:8200:c032:dcaf ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.746/0.746/0.746/0.000 ms
rk@show-01-venue:~$ sudo ip netns exec showc ping 2001:df0:8500:ca5b:0::1234:abcd
PING 2001:df0:8500:ca5b:0::1234:abcd (2001:df0:8500:ca5b::1234:abcd) 56 data bytes
64 bytes from 2001:df0:8500:ca5b::1234:abcd: icmp_seq=1 ttl=60 time=0.431 ms
^C
--- 2001:df0:8500:ca5b:0::1234:abcd ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.431/0.431/0.431/0.000 ms
rk@show-01-venue:~$ sudo ip netns exec showc ping 2001:df0:8500:ca5b:0::abcd:1234
PING 2001:df0:8500:ca5b:0::abcd:1234 (2001:df0:8500:ca5b::abcd:1234) 56 data bytes
64 bytes from 2001:df0:8500:ca5b::abcd:1234: icmp_seq=1 ttl=60 time=0.341 ms
^C
--- 2001:df0:8500:ca5b:0::abcd:1234 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.341/0.341/0.341/0.000 ms
rk@show-01-venue:~$