networkd: Remove usage of ovs-vlan-bug-workaround (#6684)

networkd had code to call ovs-vlan-bug-workaround, but this has been
made obsolete as the bug in question only applies to kernels before
2.6.37, which is long out of support.

We can safely remove the functionality associated with applying the
workaround.

Author: robhoes

ocaml/networkd/bin/network_server.ml

@@ -933,12 +933,6 @@ module Bridge = struct
                   "standalone"
                 )
             in
-            let vlan_bug_workaround =
-              if List.mem_assoc "vlan-bug-workaround" other_config then
-                Some (List.assoc "vlan-bug-workaround" other_config = "true")
-              else
-                None
-            in
             let external_id =
               if List.mem_assoc "network-uuids" other_config then
                 Some
@@ -966,7 +960,7 @@ module Bridge = struct
             Option.iter (destroy_existing_vlan_ovs_bridge dbg name) vlan ;
             ignore
               (Ovs.create_bridge ?mac ~fail_mode ?external_id ?disable_in_band
-                 ?igmp_snooping vlan vlan_bug_workaround name
+                 ?igmp_snooping vlan name
               ) ;
             if igmp_snooping = Some true && not old_igmp_snooping then
               Ovs.inject_igmp_query ~name

ocaml/networkd/lib/network_utils.ml

@@ -51,8 +51,6 @@ let ovs_ofctl = "/usr/bin/ovs-ofctl"
 
 let ovs_appctl = "/usr/bin/ovs-appctl"
 
-let ovs_vlan_bug_workaround = "/usr/sbin/ovs-vlan-bug-workaround"
-
 let brctl = ref "/sbin/brctl"
 
 let modprobe = "/sbin/modprobe"
@@ -274,25 +272,6 @@ module Sysfs = struct
         Result.Error
           (Fail_to_get_driver_name, "Failed to get driver name for: " ^ dev)
 
-  (** Returns the features bitmap for the driver for [dev]. The features bitmap
-      is a set of NETIF_F_ flags supported by its driver. *)
-  let get_features dev =
-    try Some (int_of_string (read_one_line (getpath dev "features")))
-    with _ -> None
-
-  (** Returns [true] if [dev] supports VLAN acceleration, [false] otherwise. *)
-  let has_vlan_accel dev =
-    let flag_NETIF_F_HW_VLAN_TX = 128 in
-    let flag_NETIF_F_HW_VLAN_RX = 256 in
-    let flag_NETIF_F_VLAN =
-      flag_NETIF_F_HW_VLAN_TX lor flag_NETIF_F_HW_VLAN_RX
-    in
-    match get_features dev with
-    | None ->
-        false
-    | Some features ->
-        features land flag_NETIF_F_VLAN <> 0
-
   let set_multicast_snooping bridge value =
     try
       let path = getpath bridge "bridge/multicast_snooping" in
@@ -1352,44 +1331,6 @@ module Ovs = struct
           )
       with _ -> warn "Failed to set max-idle=%d on OVS" t
 
-    let handle_vlan_bug_workaround override bridge =
-      (* This is a list of drivers that do support VLAN tx or rx acceleration,
-         but to which the VLAN bug workaround should not be applied. This could
-         be because these are known-good drivers (that is, they do not have any
-         of the bugs that the workaround avoids) or because the VLAN bug
-         workaround will not work for them and may cause other problems.
-
-         This is a very short list because few drivers have been tested. *)
-      let no_vlan_workaround_drivers = ["bonding"] in
-      let phy_interfaces =
-        try
-          let interfaces = bridge_to_interfaces bridge in
-          List.filter Sysfs.is_physical interfaces
-        with _ -> []
-      in
-      List.iter
-        (fun interface ->
-          let do_workaround =
-            match override with
-            | Some value ->
-                value
-            | None -> (
-              match Sysfs.get_driver_name interface with
-              | None ->
-                  Sysfs.has_vlan_accel interface
-              | Some driver ->
-                  if List.mem driver no_vlan_workaround_drivers then
-                    false
-                  else
-                    Sysfs.has_vlan_accel interface
-            )
-          in
-          let setting = if do_workaround then "on" else "off" in
-          try ignore (call_script ovs_vlan_bug_workaround [interface; setting])
-          with _ -> ()
-        )
-        phy_interfaces
-
     let get_vlans name =
       try
         let vlans_with_uuid =
@@ -1486,13 +1427,12 @@ module Ovs = struct
       ["--"; "--may-exist"; "add-port"; bridge; name] @ type_args
 
     let create_bridge ?mac ?external_id ?disable_in_band ?igmp_snooping
-        ~fail_mode vlan vlan_bug_workaround name =
+        ~fail_mode vlan name =
       let vlan_arg =
         match vlan with
         | None ->
             []
         | Some (parent, tag) ->
-            handle_vlan_bug_workaround vlan_bug_workaround parent ;
             [parent; string_of_int tag]
       in
       let mac_arg =