1c1ade5062
Since dhcpd has been hardened (DynamicUser → NoNewPrivileges) it can't use a setcap wrapper. Instead, we add the net_admin capability to it's ambient set and run `ip route` directly. This is also safer that giving everyone permisison to change the routing table.
285 lines
11 KiB
Nix
285 lines
11 KiB
Nix
# This test verifies that we can request and assign IPv6 prefixes from upstream
|
|
# (e.g. ISP) routers.
|
|
# The setup consits of three VMs. One for the ISP, as your residential router
|
|
# and the third as a client machine in the residential network.
|
|
#
|
|
# There are two VLANs in this test:
|
|
# - VLAN 1 is the connection between the ISP and the router
|
|
# - VLAN 2 is the connection between the router and the client
|
|
|
|
import ./make-test-python.nix ({pkgs, ...}: {
|
|
name = "systemd-networkd-ipv6-prefix-delegation";
|
|
meta = with pkgs.lib.maintainers; {
|
|
maintainers = [ andir ];
|
|
};
|
|
nodes = {
|
|
|
|
# The ISP's routers job is to delegate IPv6 prefixes via DHCPv6. Like with
|
|
# regular IPv6 auto-configuration it will also emit IPv6 router
|
|
# advertisements (RAs). Those RA's will not carry a prefix but in contrast
|
|
# just set the "Other" flag to indicate to the receiving nodes that they
|
|
# should attempt DHCPv6.
|
|
#
|
|
# Note: On the ISPs device we don't really care if we are using networkd in
|
|
# this example. That being said we can't use it (yet) as networkd doesn't
|
|
# implement the serving side of DHCPv6. We will use ISC's well aged dhcpd6
|
|
# for that task.
|
|
isp = { lib, pkgs, ... }: {
|
|
virtualisation.vlans = [ 1 ];
|
|
networking = {
|
|
useDHCP = false;
|
|
firewall.enable = false;
|
|
interfaces.eth1.ipv4.addresses = lib.mkForce []; # no need for legacy IP
|
|
interfaces.eth1.ipv6.addresses = lib.mkForce [
|
|
{ address = "2001:DB8::1"; prefixLength = 64; }
|
|
];
|
|
};
|
|
|
|
# Since we want to program the routes that we delegate to the "customer"
|
|
# into our routing table we must give dhcpd the required privs.
|
|
systemd.services.dhcpd6.serviceConfig.AmbientCapabilities =
|
|
[ "CAP_NET_ADMIN" ];
|
|
|
|
services = {
|
|
# Configure the DHCPv6 server
|
|
#
|
|
# We will hand out /48 prefixes from the subnet 2001:DB8:F000::/36.
|
|
# That gives us ~8k prefixes. That should be enough for this test.
|
|
#
|
|
# Since (usually) you will not receive a prefix with the router
|
|
# advertisements we also hand out /128 leases from the range
|
|
# 2001:DB8:0000:0000:FFFF::/112.
|
|
dhcpd6 = {
|
|
enable = true;
|
|
interfaces = [ "eth1" ];
|
|
extraConfig = ''
|
|
subnet6 2001:DB8::/36 {
|
|
range6 2001:DB8:0000:0000:FFFF:: 2001:DB8:0000:0000:FFFF::FFFF;
|
|
prefix6 2001:DB8:F000:: 2001:DB8:FFFF:: /48;
|
|
}
|
|
|
|
# This is the secret sauce. We have to extract the prefix and the
|
|
# next hop when commiting the lease to the database. dhcpd6
|
|
# (rightfully) has not concept of adding routes to the systems
|
|
# routing table. It really depends on the setup.
|
|
#
|
|
# In a production environment your DHCPv6 server is likely not the
|
|
# router. You might want to consider BGP, custom NetConf calls, …
|
|
# in those cases.
|
|
on commit {
|
|
set IP = pick-first-value(binary-to-ascii(16, 16, ":", substring(option dhcp6.ia-na, 16, 16)), "n/a");
|
|
set Prefix = pick-first-value(binary-to-ascii(16, 16, ":", suffix(option dhcp6.ia-pd, 16)), "n/a");
|
|
set PrefixLength = pick-first-value(binary-to-ascii(10, 8, ":", substring(suffix(option dhcp6.ia-pd, 17), 0, 1)), "n/a");
|
|
log(concat(IP, " ", Prefix, " ", PrefixLength));
|
|
execute("${pkgs.iproute2}/bin/ip", "-6", "route", "replace", concat(Prefix,"/",PrefixLength), "via", IP);
|
|
}
|
|
'';
|
|
};
|
|
|
|
# Finally we have to set up the router advertisements. While we could be
|
|
# using networkd or bird for this task `radvd` is probably the most
|
|
# venerable of them all. It was made explicitly for this purpose and
|
|
# the configuration is much more straightforward than what networkd
|
|
# requires.
|
|
# As outlined above we will have to set the `Managed` flag as otherwise
|
|
# the clients will not know if they should do DHCPv6. (Some do
|
|
# anyway/always)
|
|
radvd = {
|
|
enable = true;
|
|
config = ''
|
|
interface eth1 {
|
|
AdvSendAdvert on;
|
|
AdvManagedFlag on;
|
|
AdvOtherConfigFlag off; # we don't really have DNS or NTP or anything like that to distribute
|
|
prefix ::/64 {
|
|
AdvOnLink on;
|
|
AdvAutonomous on;
|
|
};
|
|
};
|
|
'';
|
|
};
|
|
|
|
};
|
|
};
|
|
|
|
# This will be our (residential) router that receives the IPv6 prefix (IA_PD)
|
|
# and /128 (IA_NA) allocation.
|
|
#
|
|
# Here we will actually start using networkd.
|
|
router = {
|
|
virtualisation.vlans = [ 1 2 ];
|
|
systemd.services.systemd-networkd.environment.SYSTEMD_LOG_LEVEL = "debug";
|
|
|
|
boot.kernel.sysctl = {
|
|
# we want to forward packets from the ISP to the client and back.
|
|
"net.ipv6.conf.all.forwarding" = 1;
|
|
};
|
|
|
|
networking = {
|
|
useNetworkd = true;
|
|
useDHCP = false;
|
|
# Consider enabling this in production and generating firewall rules
|
|
# for fowarding/input from the configured interfaces so you do not have
|
|
# to manage multiple places
|
|
firewall.enable = false;
|
|
};
|
|
|
|
systemd.network = {
|
|
networks = {
|
|
# systemd-networkd will load the first network unit file
|
|
# that matches, ordered lexiographically by filename.
|
|
# /etc/systemd/network/{40-eth1,99-main}.network already
|
|
# exists. This network unit must be loaded for the test,
|
|
# however, hence why this network is named such.
|
|
|
|
# Configuration of the interface to the ISP.
|
|
# We must request accept RAs and request the PD prefix.
|
|
"01-eth1" = {
|
|
name = "eth1";
|
|
networkConfig = {
|
|
Description = "ISP interface";
|
|
IPv6AcceptRA = true;
|
|
#DHCP = false; # no need for legacy IP
|
|
};
|
|
linkConfig = {
|
|
# We care about this interface when talking about being "online".
|
|
# If this interface is in the `routable` state we can reach
|
|
# others and they should be able to reach us.
|
|
RequiredForOnline = "routable";
|
|
};
|
|
# This configures the DHCPv6 client part towards the ISPs DHCPv6 server.
|
|
dhcpV6Config = {
|
|
# We have to include a request for a prefix in our DHCPv6 client
|
|
# request packets.
|
|
# Otherwise the upstream DHCPv6 server wouldn't know if we want a
|
|
# prefix or not. Note: On some installation it makes sense to
|
|
# always force that option on the DHPCv6 server since there are
|
|
# certain CPEs that are just not setting this field but happily
|
|
# accept the delegated prefix.
|
|
PrefixDelegationHint = "::/48";
|
|
};
|
|
ipv6SendRAConfig = {
|
|
# Let networkd know that we would very much like to use DHCPv6
|
|
# to obtain the "managed" information. Not sure why they can't
|
|
# just take that from the upstream RAs.
|
|
Managed = true;
|
|
};
|
|
};
|
|
|
|
# Interface to the client. Here we should redistribute a /64 from
|
|
# the prefix we received from the ISP.
|
|
"01-eth2" = {
|
|
name = "eth2";
|
|
networkConfig = {
|
|
Description = "Client interface";
|
|
# The client shouldn't be allowed to send us RAs, that would be weird.
|
|
IPv6AcceptRA = false;
|
|
|
|
# Delegate prefixes from the DHCPv6 PD pool.
|
|
DHCPv6PrefixDelegation = true;
|
|
IPv6SendRA = true;
|
|
};
|
|
|
|
# In a production environment you should consider setting these as well:
|
|
# ipv6SendRAConfig = {
|
|
#EmitDNS = true;
|
|
#EmitDomains = true;
|
|
#DNS= = "fe80::1"; # or whatever "well known" IP your router will have on the inside.
|
|
# };
|
|
|
|
# This adds a "random" ULA prefix to the interface that is being
|
|
# advertised to the clients.
|
|
# Not used in this test.
|
|
# ipv6Prefixes = [
|
|
# {
|
|
# ipv6PrefixConfig = {
|
|
# AddressAutoconfiguration = true;
|
|
# PreferredLifetimeSec = 1800;
|
|
# ValidLifetimeSec = 1800;
|
|
# };
|
|
# }
|
|
# ];
|
|
};
|
|
|
|
# finally we are going to add a static IPv6 unique local address to
|
|
# the "lo" interface. This will serve as ICMPv6 echo target to
|
|
# verify connectivity from the client to the router.
|
|
"01-lo" = {
|
|
name = "lo";
|
|
addresses = [
|
|
{ addressConfig.Address = "FD42::1/128"; }
|
|
];
|
|
};
|
|
};
|
|
};
|
|
|
|
# make the network-online target a requirement, we wait for it in our test script
|
|
systemd.targets.network-online.wantedBy = [ "multi-user.target" ];
|
|
};
|
|
|
|
# This is the client behind the router. We should be receving router
|
|
# advertisements for both the ULA and the delegated prefix.
|
|
# All we have to do is boot with the default (networkd) configuration.
|
|
client = {
|
|
virtualisation.vlans = [ 2 ];
|
|
systemd.services.systemd-networkd.environment.SYSTEMD_LOG_LEVEL = "debug";
|
|
networking = {
|
|
useNetworkd = true;
|
|
useDHCP = false;
|
|
};
|
|
|
|
# make the network-online target a requirement, we wait for it in our test script
|
|
systemd.targets.network-online.wantedBy = [ "multi-user.target" ];
|
|
};
|
|
};
|
|
|
|
testScript = ''
|
|
# First start the router and wait for it it reach a state where we are
|
|
# certain networkd is up and it is able to send out RAs
|
|
router.start()
|
|
router.wait_for_unit("systemd-networkd.service")
|
|
|
|
# After that we can boot the client and wait for the network online target.
|
|
# Since we only care about IPv6 that should not involve waiting for legacy
|
|
# IP leases.
|
|
client.start()
|
|
client.wait_for_unit("network-online.target")
|
|
|
|
# the static address on the router should not be reachable
|
|
client.wait_until_succeeds("ping -6 -c 1 FD42::1")
|
|
|
|
# the global IP of the ISP router should still not be a reachable
|
|
router.fail("ping -6 -c 1 2001:DB8::1")
|
|
|
|
# Once we have internal connectivity boot up the ISP
|
|
isp.start()
|
|
|
|
# Since for the ISP "being online" should have no real meaning we just
|
|
# wait for the target where all the units have been started.
|
|
# It probably still takes a few more seconds for all the RA timers to be
|
|
# fired etc..
|
|
isp.wait_for_unit("multi-user.target")
|
|
|
|
# wait until the uplink interface has a good status
|
|
router.wait_for_unit("network-online.target")
|
|
router.wait_until_succeeds("ping -6 -c1 2001:DB8::1")
|
|
|
|
# shortly after that the client should have received it's global IPv6
|
|
# address and thus be able to ping the ISP
|
|
client.wait_until_succeeds("ping -6 -c1 2001:DB8::1")
|
|
|
|
# verify that we got a globally scoped address in eth1 from the
|
|
# documentation prefix
|
|
ip_output = client.succeed("ip --json -6 address show dev eth1")
|
|
|
|
import json
|
|
|
|
ip_json = json.loads(ip_output)[0]
|
|
assert any(
|
|
addr["local"].upper().startswith("2001:DB8:")
|
|
for addr in ip_json["addr_info"]
|
|
if addr["scope"] == "global"
|
|
)
|
|
'';
|
|
})
|