make a module for vlan

Acked-by: Daniel Barlow <<dan@telent.net>>

devices/gl-mt300a/default.nix

@@ -115,6 +115,7 @@
           NET_RALINK_MDIO = "y";
           NET_RALINK_MDIO_MT7620 = "y";
           NET_RALINK_MT7620 = "y";
+          SWPHY = "y";
 
           SPI = "y";
           MTD_SPI_NOR = "y";
@@ -123,14 +124,6 @@
           SPI_MASTER= "y";
           SPI_MEM= "y";
 
-          # both the ethernet ports on this device (lan and wan)
-          # are behind a switch, so we need VLANs to do anything
-          # useful with them
-
-          VLAN_8021Q = "y";
-          SWCONFIG = "y";
-          SWPHY = "y";
-
           MTD = "y";
           MTD_CMDLINE_PARTS = "y";
           MTD_BLOCK = "y";         # fix undefined ref to register_mtd_blktrans_devs

devices/gl-mt300n-v2/default.nix

@@ -52,10 +52,11 @@
             "${openwrt.src}/target/linux/ramips/dts"
           ];
         };
-        networkInterfaces = rec {
-          # lan and wan ports are both behind a switch on eth0
-          eth =
-            let swconfig = oneshot {
+        networkInterfaces =
+          let
+            inherit (config.system.service.network) link;
+            inherit (config.system.service) vlan;
+            swconfig = oneshot {
               name = "swconfig";
               up = ''
                 PATH=${pkgs.swconfig}/bin:$PATH
@@ -67,26 +68,21 @@
               '';
               down = "swconfig dev switch0 set reset";
             };
-            in interface {
-              device = "eth0";
-              dependencies =  [swconfig];
+          in rec {
+            eth = link.build { ifname = "eth0"; dependencies =  [swconfig]; };
+            # lan and wan ports are both behind a switch on eth0
+            lan = vlan.build {
+              ifname = "eth0.1";
+              primary = eth;
+              vid = "1";
             };
-          lan = interface {
-            type = "vlan";
-            device = "eth0.1";
-            link = "eth0";
-            id = "1";
-            dependencies = [eth];
+            wan = vlan.build {
+              ifname = "eth0.2";
+              primary = eth;
+              vid = "2";
             };
-          wan = interface {
-            type = "vlan";
-            device = "eth0.2";
-            id = "2";
-            link = "eth0";
-            dependencies = [eth];
-          };
-          wlan = interface {
-            device = "wlan0";
+            wlan = link.build {
+              ifname = "wlan0";
               dependencies = [ mac80211 ];
             };
           };
@@ -148,13 +144,6 @@
           NET_VENDOR_RALINK = "y";
           NET_RALINK_RT3050 = "y";
           NET_RALINK_SOC="y";
-
-          # both the ethernet ports on this device (lan and wan)
-          # are behind a switch, so we need VLANs to do anything
-          # useful with them
-
-          VLAN_8021Q = "y";
-          SWCONFIG = "y";
           SWPHY = "y";
 
           WATCHDOG = "y";

examples/arhcive.nix

@@ -31,6 +31,7 @@ in rec {
     ../modules/standard.nix
     ../modules/wlan.nix
     ../modules/network
+    ../modules/vlan
   ];
 
   hostname = "arhcive";

modules/vlan/default.nix

@@ -0,0 +1,41 @@
+## VLAN
+## ====
+##
+## Virtual LANs give you the ability to sub-divide a LAN. Linux can
+## accept VLAN tagged traffic and presents each VLAN ID as a
+## different network interface (eg: eth0.100 for VLAN ID 100)
+##
+## Some Liminix devices with multiple ethernet ports are implemented
+## using a network switch connecting the physical ports to the CPU,
+## and require using VLAN in order to send different traffic to
+## different ports (e.g. LAN vs WAN)
+
+{ lib, pkgs, config, ...}:
+let
+  inherit (lib) mkOption types;
+  inherit (pkgs.liminix.services) oneshot;
+  inherit (pkgs) liminix;
+in
+{
+  options = {
+    system.service.vlan = mkOption { type = liminix.lib.types.serviceDefn; };
+  };
+  config.system.service.vlan = liminix.callService ./service.nix {
+    ifname = mkOption {
+      type = types.str;
+      description = "interface name to create";
+    };
+    primary = mkOption {
+      description = "existing physical interface";
+      type = liminix.lib.types.interface;
+    };
+    vid = mkOption {
+      description = "VLAN identifier (VID) in range 1-4094";
+      type = types.str;
+    };
+  };
+  config.kernel.config = {
+    VLAN_8021Q = "y";
+    SWCONFIG = "y"; # not always appropriate, some devices will use DSA
+  };
+}

modules/vlan/service.nix

@@ -0,0 +1,15 @@
+{
+  liminix
+, lib
+}:
+{ ifname, primary, vid } :
+let
+  inherit (liminix.services) oneshot;
+in oneshot rec {
+  name = "${ifname}.link";
+  up = ''
+    ip link add link $(output ${primary} ifname) name ${ifname} type vlan id ${vid}
+    ${liminix.networking.ifup name ifname}
+  '';
+  down = "ip link set down dev ${ifname}";
+}