d4d5fd718d
We can expose the PLAT prefix to the client via DNS64 so clatd is able to determine the prefix dynamically. We can also test that some systemd-networkd PREF64 settings work as expected when exposed on the router.
237 lines
7.3 KiB
Nix
237 lines
7.3 KiB
Nix
# This test verifies that we can ping an IPv4-only server from an IPv6-only
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# client via a NAT64 router using CLAT on the client. The hosts and networks
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# are configured as follows:
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#
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# +------
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# Client | clat Address: 192.0.0.1/32 (configured via clatd)
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# | Route: default
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# |
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# | eth1 Address: Assigned via SLAAC within 2001:db8::/64
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# | | Route: default via IPv6LL address
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# +--|---
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# | VLAN 3
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# +--|---
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# | eth2 Address: 2001:db8::1/64
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# Router |
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# | nat64 Address: 64:ff9b::1/128
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# | Route: 64:ff9b::/96
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# | Address: 192.0.2.0/32
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# | Route: 192.0.2.0/24
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# |
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# | eth1 Address: 100.64.0.1/24
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# +--|---
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# | VLAN 2
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# +--|---
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# Server | eth1 Address: 100.64.0.2/24
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# | Route: 192.0.2.0/24 via 100.64.0.1
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# +------
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import ./make-test-python.nix ({ pkgs, lib, ... }:
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{
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name = "clatd";
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meta = with pkgs.lib.maintainers; {
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maintainers = [ hax404 jmbaur ];
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};
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nodes = {
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# The server is configured with static IPv4 addresses. RFC 6052 Section 3.1
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# disallows the mapping of non-global IPv4 addresses like RFC 1918 into the
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# Well-Known Prefix 64:ff9b::/96. TAYGA also does not allow the mapping of
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# documentation space (RFC 5737). To circumvent this, 100.64.0.2/24 from
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# RFC 6589 (Carrier Grade NAT) is used here.
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# To reach the IPv4 address pool of the NAT64 gateway, there is a static
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# route configured. In normal cases, where the router would also source NAT
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# the pool addresses to one IPv4 addresses, this would not be needed.
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server = {
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virtualisation.vlans = [
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2 # towards router
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];
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networking = {
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useDHCP = false;
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interfaces.eth1 = lib.mkForce {};
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};
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systemd.network = {
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enable = true;
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networks."vlan1" = {
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matchConfig.Name = "eth1";
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address = [
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"100.64.0.2/24"
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];
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routes = [
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{ Destination = "192.0.2.0/24"; Gateway = "100.64.0.1"; }
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];
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};
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};
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};
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# The router is configured with static IPv4 addresses towards the server
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# and IPv6 addresses towards the client. DNS64 is exposed towards the
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# client so clatd is able to auto-discover the PLAT prefix. For NAT64, the
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# Well-Known prefix 64:ff9b::/96 is used. NAT64 is done with TAYGA which
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# provides the tun-interface nat64 and does the translation over it. The
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# IPv6 packets are sent to this interfaces and received as IPv4 packets and
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# vice versa. As TAYGA only translates IPv6 addresses to dedicated IPv4
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# addresses, it needs a pool of IPv4 addresses which must be at least as
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# big as the expected amount of clients. In this test, the packets from the
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# pool are directly routed towards the client. In normal cases, there would
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# be a second source NAT44 to map all clients behind one IPv4 address.
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router = {
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boot.kernel.sysctl = {
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"net.ipv4.conf.all.forwarding" = 1;
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"net.ipv6.conf.all.forwarding" = 1;
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};
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virtualisation.vlans = [
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2 # towards server
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3 # towards client
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];
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networking = {
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useDHCP = false;
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useNetworkd = true;
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firewall.enable = false;
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interfaces.eth1 = lib.mkForce {
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ipv4 = {
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addresses = [ { address = "100.64.0.1"; prefixLength = 24; } ];
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};
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};
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interfaces.eth2 = lib.mkForce {
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ipv6 = {
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addresses = [ { address = "2001:db8::1"; prefixLength = 64; } ];
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};
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};
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};
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systemd.network.networks."40-eth2" = {
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networkConfig.IPv6SendRA = true;
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ipv6Prefixes = [ { Prefix = "2001:db8::/64"; } ];
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ipv6PREF64Prefixes = [ { Prefix = "64:ff9b::/96"; } ];
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ipv6SendRAConfig = {
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EmitDNS = true;
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DNS = "_link_local";
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};
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};
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services.resolved.extraConfig = ''
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DNSStubListener=no
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'';
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networking.extraHosts = ''
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192.0.0.171 ipv4only.arpa
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192.0.0.170 ipv4only.arpa
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'';
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services.coredns = {
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enable = true;
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config = ''
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.:53 {
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bind ::
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hosts /etc/hosts
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dns64 64:ff9b::/96
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}
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'';
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};
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services.tayga = {
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enable = true;
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ipv4 = {
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address = "192.0.2.0";
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router = {
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address = "192.0.2.1";
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};
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pool = {
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address = "192.0.2.0";
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prefixLength = 24;
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};
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};
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ipv6 = {
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address = "2001:db8::1";
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router = {
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address = "64:ff9b::1";
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};
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pool = {
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address = "64:ff9b::";
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prefixLength = 96;
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};
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};
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};
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};
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# The client uses SLAAC to assign IPv6 addresses. To reach the IPv4-only
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# server, the client starts the clat daemon which starts and configures the
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# local IPv4 -> IPv6 translation via Tayga after discovering the PLAT
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# prefix via DNS64.
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client = {
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virtualisation.vlans = [
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3 # towards router
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];
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networking = {
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useDHCP = false;
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interfaces.eth1 = lib.mkForce {};
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};
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systemd.network = {
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enable = true;
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networks."vlan1" = {
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matchConfig.Name = "eth1";
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# NOTE: clatd does not actually use the PREF64 prefix discovered by
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# systemd-networkd (nor does systemd-networkd do anything with it,
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# yet), but we set this to confirm it works. See the test script
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# below.
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ipv6AcceptRAConfig.UsePREF64 = true;
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};
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};
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services.clatd = {
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enable = true;
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# NOTE: Perl's Net::DNS resolver does not seem to work well querying
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# for AAAA records to systemd-resolved's default IPv4 bind address
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# (127.0.0.53), so we add an IPv6 listener address to systemd-resolved
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# and tell clatd to use that instead.
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settings.dns64-servers = "::1";
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};
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# Allow clatd to find dns server. See comment above.
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services.resolved.extraConfig = ''
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DNSStubListenerExtra=::1
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'';
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environment.systemPackages = [ pkgs.mtr ];
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};
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};
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testScript = ''
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import json
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start_all()
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# wait for all machines to start up
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for machine in client, router, server:
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machine.wait_for_unit("network-online.target")
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with subtest("Wait for tayga and clatd"):
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router.wait_for_unit("tayga.service")
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client.wait_for_unit("clatd.service")
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# clatd checks if this system has IPv4 connectivity for 10 seconds
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client.wait_until_succeeds(
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'journalctl -u clatd -e | grep -q "Starting up TAYGA, using config file"'
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)
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with subtest("networkd exports PREF64 prefix"):
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assert json.loads(client.succeed("networkctl status eth1 --json=short"))[
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"NDisc"
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]["PREF64"][0]["Prefix"] == [0x0, 0x64, 0xFF, 0x9B] + ([0] * 12)
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with subtest("Test ICMP"):
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client.wait_until_succeeds("ping -c 3 100.64.0.2 >&2")
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with subtest("Test ICMP and show a traceroute"):
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client.wait_until_succeeds("mtr --show-ips --report-wide 100.64.0.2 >&2")
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client.log(client.execute("systemd-analyze security clatd.service")[1])
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'';
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})
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