nixpkgs/modules/tasks/network-interfaces.nix
David Guibert ed6e0262e0 bring bridge interfaces up
The bridge is not becoming operational until it is brought into the UP state.
When the bridge is statically configured, this is mandatory.
2013-03-02 10:24:46 +01:00

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{ config, pkgs, ... }:
with pkgs.lib;
let
cfg = config.networking;
interfaces = attrValues cfg.interfaces;
hasVirtuals = any (i: i.virtual) interfaces;
interfaceOpts = { name, ... }: {
options = {
name = mkOption {
example = "eth0";
type = types.string;
description = "Name of the interface.";
};
ipAddress = mkOption {
default = null;
example = "10.0.0.1";
type = types.nullOr types.string;
description = ''
IP address of the interface. Leave empty to configure the
interface using DHCP.
'';
};
prefixLength = mkOption {
default = null;
example = 24;
type = types.nullOr types.int;
description = ''
Subnet mask of the interface, specified as the number of
bits in the prefix (<literal>24</literal>).
'';
};
subnetMask = mkOption {
default = "";
example = "255.255.255.0";
type = types.string;
description = ''
Subnet mask of the interface, specified as a bitmask.
This is deprecated; use <option>prefixLength</option>
instead.
'';
};
macAddress = mkOption {
default = null;
example = "00:11:22:33:44:55";
type = types.nullOr types.string;
description = ''
MAC address of the interface. Leave empty to use the default.
'';
};
virtual = mkOption {
default = false;
type = types.bool;
description = ''
Whether this interface is virtual and should be created by tunctl.
This is mainly useful for creating bridges between a host a virtual
network such as VPN or a virtual machine.
Defaults to tap device, unless interface contains "tun" in its name.
'';
};
virtualOwner = mkOption {
default = "root";
type = types.uniq types.string;
description = ''
In case of a virtual device, the user who owns it.
'';
};
proxyARP = mkOption {
default = false;
type = types.bool;
description = ''
Turn on proxy_arp for this device (and proxy_ndp for ipv6).
This is mainly useful for creating pseudo-bridges between a real
interface and a virtual network such as VPN or a virtual machine for
interfaces that don't support real bridging (most wlan interfaces).
As ARP proxying acts slightly above the link-layer, below-ip traffic
isn't bridged, so things like DHCP won't work. The advantage above
using NAT lies in the fact that no IP addresses are shared, so all
hosts are reachable/routeable.
WARNING: turns on ip-routing, so if you have multiple interfaces, you
should think of the consequence and setup firewall rules to limit this.
'';
};
};
config = {
name = mkDefault name;
};
};
in
{
###### interface
options = {
networking.hostName = mkOption {
default = "nixos";
description = ''
The name of the machine. Leave it empty if you want to obtain
it from a DHCP server (if using DHCP).
'';
};
networking.enableIPv6 = mkOption {
default = true;
description = ''
Whether to enable support for IPv6.
'';
};
networking.defaultGateway = mkOption {
default = "";
example = "131.211.84.1";
description = ''
The default gateway. It can be left empty if it is auto-detected through DHCP.
'';
};
networking.defaultGatewayWindowSize = mkOption {
default = null;
example = 524288;
type = types.nullOr types.int;
description = ''
The window size of the default gateway. It limits maximal data bursts that TCP peers
are allowed to send to us.
'';
};
networking.nameservers = mkOption {
default = [];
example = ["130.161.158.4" "130.161.33.17"];
description = ''
The list of nameservers. It can be left empty if it is auto-detected through DHCP.
'';
};
networking.domain = mkOption {
default = "";
example = "home";
description = ''
The domain. It can be left empty if it is auto-detected through DHCP.
'';
};
networking.localCommands = mkOption {
default = "";
example = "text=anything; echo You can put $text here.";
description = ''
Shell commands to be executed at the end of the
<literal>network-interfaces</literal> Upstart job. Note that if
you are using DHCP to obtain the network configuration,
interfaces may not be fully configured yet.
'';
};
networking.interfaces = mkOption {
default = {};
example =
{ eth0 = {
ipAddress = "131.211.84.78";
subnetMask = "255.255.255.128";
};
};
description = ''
The configuration for each network interface. If
<option>networking.useDHCP</option> is true, then every
interface not listed here will be configured using DHCP.
'';
type = types.loaOf types.optionSet;
options = [ interfaceOpts ];
};
networking.bridges = mkOption {
default = { };
example =
{ br0.interfaces = [ "eth0" "eth1" ];
br1.interfaces = [ "eth2" "wlan0" ];
};
description =
''
This option allows you to define Ethernet bridge devices
that connect physical networks together. The value of this
option is an attribute set. Each attribute specifies a
bridge, with the attribute name specifying the name of the
bridge's network interface.
'';
type = types.attrsOf types.optionSet;
options = {
interfaces = mkOption {
example = [ "eth0" "eth1" ];
type = types.listOf types.string;
description =
"The physical network interfaces connected by the bridge.";
};
};
};
networking.useDHCP = mkOption {
default = true;
merge = mergeEnableOption;
description = ''
Whether to use DHCP to obtain an IP adress and other
configuration for all network interfaces that are not manually
configured.
'';
};
};
###### implementation
config = {
boot.kernelModules = optional cfg.enableIPv6 "ipv6" ++ optional hasVirtuals "tun";
environment.systemPackages =
[ pkgs.host
pkgs.iproute
pkgs.iputils
pkgs.nettools
pkgs.wirelesstools
pkgs.rfkill
pkgs.openresolv
]
++ optional (cfg.bridges != {}) pkgs.bridge_utils
++ optional hasVirtuals pkgs.tunctl
++ optional cfg.enableIPv6 pkgs.ndisc6;
security.setuidPrograms = [ "ping" "ping6" ];
systemd.targets."network-interfaces" =
{ description = "All Network Interfaces";
wantedBy = [ "network.target" ];
unitConfig.X-StopOnReconfiguration = true;
};
systemd.services =
let
networkSetup =
{ description = "Networking Setup";
after = [ "network-interfaces.target" ];
before = [ "network.target" ];
wantedBy = [ "network.target" ];
path = [ pkgs.iproute ];
serviceConfig.Type = "oneshot";
serviceConfig.RemainAfterExit = true;
script =
''
# Set the static DNS configuration, if given.
cat | ${pkgs.openresolv}/sbin/resolvconf -a static <<EOF
${optionalString (cfg.nameservers != [] && cfg.domain != "") ''
domain ${cfg.domain}
''}
${flip concatMapStrings cfg.nameservers (ns: ''
nameserver ${ns}
'')}
EOF
# Disable or enable IPv6.
if [ -e /proc/sys/net/ipv6/conf/all/disable_ipv6 ]; then
echo ${if cfg.enableIPv6 then "0" else "1"} > /proc/sys/net/ipv6/conf/all/disable_ipv6
fi
# Set the default gateway.
${optionalString (cfg.defaultGateway != "") ''
# FIXME: get rid of "|| true" (necessary to make it idempotent).
ip route add default via "${cfg.defaultGateway}" ${
optionalString (cfg.defaultGatewayWindowSize != null)
"window ${cfg.defaultGatewayWindowSize}"} || true
''}
# Turn on forwarding if any interface has enabled proxy_arp.
${optionalString (any (i: i.proxyARP) interfaces) ''
echo 1 > /proc/sys/net/ipv4/ip_forward
''}
# Run any user-specified commands.
${cfg.localCommands}
'';
};
# For each interface <foo>, create a job <foo>-cfg.service"
# that performs static configuration. It has a "wants"
# dependency on <foo>.service, which is supposed to create
# the interface and need not exist (i.e. for hardware
# interfaces). It has a binds-to dependency on the actual
# network device, so it only gets started after the interface
# has appeared, and it's stopped when the interface
# disappears.
configureInterface = i: nameValuePair "${i.name}-cfg"
(let mask =
if i.prefixLength != null then toString i.prefixLength else
if i.subnetMask != "" then i.subnetMask else "32";
in
{ description = "Configuration of ${i.name}";
wantedBy = [ "network-interfaces.target" ];
bindsTo = [ "sys-subsystem-net-devices-${i.name}.device" ];
after = [ "sys-subsystem-net-devices-${i.name}.device" ];
serviceConfig.Type = "oneshot";
serviceConfig.RemainAfterExit = true;
path = [ pkgs.iproute pkgs.gawk ];
script =
''
echo "bringing up interface..."
ip link set "${i.name}" up
''
+ optionalString (i.macAddress != null)
''
echo "setting MAC address to ${i.macAddress}..."
ip link set "${i.name}" address "${i.macAddress}"
''
+ optionalString (i.ipAddress != null)
''
cur=$(ip -4 -o a show dev "${i.name}" | awk '{print $4}')
# Only do a flush/add if it's necessary. This is
# useful when the Nix store is accessed via this
# interface (e.g. in a QEMU VM test).
if [ "$cur" != "${i.ipAddress}/${mask}" ]; then
echo "configuring interface..."
ip -4 addr flush dev "${i.name}"
ip -4 addr add "${i.ipAddress}/${mask}" dev "${i.name}"
# Ensure that the default gateway remains set.
# (Flushing this interface may have removed it.)
${config.systemd.package}/bin/systemctl try-restart --no-block network-setup.service
else
echo "skipping configuring interface"
fi
${config.systemd.package}/bin/systemctl start ip-up.target
''
+ optionalString i.proxyARP
''
echo 1 > /proc/sys/net/ipv4/conf/${i.name}/proxy_arp
''
+ optionalString (i.proxyARP && cfg.enableIPv6)
''
echo 1 > /proc/sys/net/ipv6/conf/${i.name}/proxy_ndp
'';
});
createTunDevice = i: nameValuePair "${i.name}"
{ description = "Virtual Network Interface ${i.name}";
requires = [ "dev-net-tun.device" ];
after = [ "dev-net-tun.device" ];
wantedBy = [ "network.target" "sys-subsystem-net-devices-${i.name}.device" ];
serviceConfig =
{ Type = "oneshot";
RemainAfterExit = true;
ExecStart = "${pkgs.tunctl}/bin/tunctl -t '${i.name}' -u '${i.virtualOwner}'";
ExecStop = "${pkgs.tunctl}/bin/tunctl -d '${i.name}'";
};
};
createBridgeDevice = n: v:
let
deps = map (i: "sys-subsystem-net-devices-${i}.device") v.interfaces;
in
{ description = "Bridge Interface ${n}";
wantedBy = [ "network.target" "sys-subsystem-net-devices-${n}.device" ];
bindsTo = deps;
after = deps;
serviceConfig.Type = "oneshot";
serviceConfig.RemainAfterExit = true;
path = [ pkgs.bridge_utils pkgs.iproute ];
script =
''
brctl addbr "${n}"
# Set bridge's hello time to 0 to avoid startup delays.
brctl setfd "${n}" 0
${flip concatMapStrings v.interfaces (i: ''
brctl addif "${n}" "${i}"
ip link set "${i}" up
ip addr flush dev "${i}"
echo "bringing up network device ${n}..."
ip link set "${n}" up
'')}
# !!! Should delete (brctl delif) any interfaces that
# no longer belong to the bridge.
'';
postStop =
''
ip link set "${n}" down
brctl delbr "${n}"
'';
};
in listToAttrs (
map configureInterface interfaces ++
map createTunDevice (filter (i: i.virtual) interfaces))
// mapAttrs createBridgeDevice cfg.bridges
// { "network-setup" = networkSetup; };
# Set the host name in the activation script. Don't clear it if
# it's not configured in the NixOS configuration, since it may
# have been set by dhclient in the meantime.
system.activationScripts.hostname =
optionalString (config.networking.hostName != "") ''
hostname "${config.networking.hostName}"
'';
services.udev.extraRules =
''
KERNEL=="tun", TAG+="systemd"
'';
};
}