# This test verifies that we can ping an IPv4-only server from an IPv6-only # client via a NAT64 router using CLAT on the client. The hosts and networks # are configured as follows: # # +------ # Client | clat Address: 192.0.0.1/32 (configured via clatd) # | Route: default # | # | eth1 Address: Assigned via SLAAC within 2001:db8::/64 # | | Route: default via IPv6LL address # +--|--- # | VLAN 3 # +--|--- # | eth2 Address: 2001:db8::1/64 # Router | # | nat64 Address: 64:ff9b::1/128 # | Route: 64:ff9b::/96 # | Address: 192.0.2.0/32 # | Route: 192.0.2.0/24 # | # | eth1 Address: 100.64.0.1/24 # +--|--- # | VLAN 2 # +--|--- # Server | eth1 Address: 100.64.0.2/24 # | Route: 192.0.2.0/24 via 100.64.0.1 # +------ import ./make-test-python.nix ( { pkgs, lib, ... }: { name = "clatd"; meta = with pkgs.lib.maintainers; { maintainers = [ hax404 jmbaur ]; }; nodes = { # The server is configured with static IPv4 addresses. RFC 6052 Section 3.1 # disallows the mapping of non-global IPv4 addresses like RFC 1918 into the # Well-Known Prefix 64:ff9b::/96. TAYGA also does not allow the mapping of # documentation space (RFC 5737). To circumvent this, 100.64.0.2/24 from # RFC 6589 (Carrier Grade NAT) is used here. # To reach the IPv4 address pool of the NAT64 gateway, there is a static # route configured. In normal cases, where the router would also source NAT # the pool addresses to one IPv4 addresses, this would not be needed. server = { virtualisation.vlans = [ 2 # towards router ]; networking = { useDHCP = false; interfaces.eth1 = lib.mkForce { }; }; systemd.network = { enable = true; networks."vlan1" = { matchConfig.Name = "eth1"; address = [ "100.64.0.2/24" ]; routes = [ { Destination = "192.0.2.0/24"; Gateway = "100.64.0.1"; } ]; }; }; }; # The router is configured with static IPv4 addresses towards the server # and IPv6 addresses towards the client. DNS64 is exposed towards the # client so clatd is able to auto-discover the PLAT prefix. For NAT64, the # Well-Known prefix 64:ff9b::/96 is used. NAT64 is done with TAYGA which # provides the tun-interface nat64 and does the translation over it. The # IPv6 packets are sent to this interfaces and received as IPv4 packets and # vice versa. As TAYGA only translates IPv6 addresses to dedicated IPv4 # addresses, it needs a pool of IPv4 addresses which must be at least as # big as the expected amount of clients. In this test, the packets from the # pool are directly routed towards the client. In normal cases, there would # be a second source NAT44 to map all clients behind one IPv4 address. router = { boot.kernel.sysctl = { "net.ipv4.conf.all.forwarding" = 1; "net.ipv6.conf.all.forwarding" = 1; }; virtualisation.vlans = [ 2 # towards server 3 # towards client ]; networking = { useDHCP = false; useNetworkd = true; firewall.enable = false; interfaces.eth1 = lib.mkForce { ipv4 = { addresses = [ { address = "100.64.0.1"; prefixLength = 24; } ]; }; }; interfaces.eth2 = lib.mkForce { ipv6 = { addresses = [ { address = "2001:db8::1"; prefixLength = 64; } ]; }; }; }; systemd.network.networks."40-eth2" = { networkConfig.IPv6SendRA = true; ipv6Prefixes = [ { Prefix = "2001:db8::/64"; } ]; ipv6PREF64Prefixes = [ { Prefix = "64:ff9b::/96"; } ]; ipv6SendRAConfig = { EmitDNS = true; DNS = "_link_local"; }; }; services.resolved.extraConfig = '' DNSStubListener=no ''; networking.extraHosts = '' 192.0.0.171 ipv4only.arpa 192.0.0.170 ipv4only.arpa ''; services.coredns = { enable = true; config = '' .:53 { bind :: hosts /etc/hosts dns64 64:ff9b::/96 } ''; }; services.tayga = { enable = true; ipv4 = { address = "192.0.2.0"; router = { address = "192.0.2.1"; }; pool = { address = "192.0.2.0"; prefixLength = 24; }; }; ipv6 = { address = "2001:db8::1"; router = { address = "64:ff9b::1"; }; pool = { address = "64:ff9b::"; prefixLength = 96; }; }; }; }; # The client uses SLAAC to assign IPv6 addresses. To reach the IPv4-only # server, the client starts the clat daemon which starts and configures the # local IPv4 -> IPv6 translation via Tayga after discovering the PLAT # prefix via DNS64. client = { virtualisation.vlans = [ 3 # towards router ]; networking = { useDHCP = false; interfaces.eth1 = lib.mkForce { }; }; systemd.network = { enable = true; networks."vlan1" = { matchConfig.Name = "eth1"; # NOTE: clatd does not actually use the PREF64 prefix discovered by # systemd-networkd (nor does systemd-networkd do anything with it, # yet), but we set this to confirm it works. See the test script # below. ipv6AcceptRAConfig.UsePREF64 = true; }; }; services.clatd = { enable = true; # NOTE: Perl's Net::DNS resolver does not seem to work well querying # for AAAA records to systemd-resolved's default IPv4 bind address # (127.0.0.53), so we add an IPv6 listener address to systemd-resolved # and tell clatd to use that instead. settings.dns64-servers = "::1"; }; # Allow clatd to find dns server. See comment above. services.resolved.extraConfig = '' DNSStubListenerExtra=::1 ''; environment.systemPackages = [ pkgs.mtr ]; }; }; testScript = '' import json start_all() # wait for all machines to start up for machine in client, router, server: machine.wait_for_unit("network-online.target") with subtest("Wait for tayga and clatd"): router.wait_for_unit("tayga.service") client.wait_for_unit("clatd.service") # clatd checks if this system has IPv4 connectivity for 10 seconds client.wait_until_succeeds( 'journalctl -u clatd -e | grep -q "Starting up TAYGA, using config file"' ) with subtest("networkd exports PREF64 prefix"): assert json.loads(client.succeed("networkctl status eth1 --json=short"))[ "NDisc" ]["PREF64"][0]["Prefix"] == [0x0, 0x64, 0xFF, 0x9B] + ([0] * 12) with subtest("Test ICMP"): client.wait_until_succeeds("ping -c 3 100.64.0.2 >&2") with subtest("Test ICMP and show a traceroute"): client.wait_until_succeeds("mtr --show-ips --report-wide 100.64.0.2 >&2") client.log(client.execute("systemd-analyze security clatd.service")[1]) ''; } )