{ 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 (24). ''; }; 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 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 network-setup systemd service. 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 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 address 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.iw 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. ${pkgs.openresolv}/sbin/resolvconf -m 1 -a static < /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. ${cfg.localCommands} ''; }; # For each interface , create a job ‘-cfg.service" # that performs static configuration. It has a "wants" # dependency on ‘.service’, which is supposed to create # the interface and need not exist (i.e. for hardware # interfaces). It has a binds-to dependency on the actual # network device, so it only gets started after the interface # has appeared, and it's stopped when the interface # disappears. configureInterface = i: nameValuePair "${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 ${i.name}"; requires = [ "dev-net-tun.device" ]; after = [ "dev-net-tun.device" ]; wantedBy = [ "network.target" ]; requiredBy = [ "sys-subsystem-net-devices-${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 and domain names 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 "${config.networking.hostName}" ''; system.activationScripts.domain = optionalString (config.networking.domain != "") '' domainname "${config.networking.domain}" ''; services.udev.extraRules = '' KERNEL=="tun", TAG+="systemd" ''; }; }