CA-219257: Make enic driver workaround configurable.

lib/network_utils.ml

@@ -74,6 +74,13 @@ module Sysfs = struct
 			warn "Failed to obtain list of drivers from sysfs";
 			[]
 
+	let get_driver_version driver () =
+		try
+			Some (String.strip String.isspace (Unixext.string_of_file ("/sys/bus/pci/drivers/" ^ driver ^ "/module/version")))
+		with _ ->
+			warn "Failed to obtain driver version from sysfs";
+			None
+
 	let getpath dev attr =
 		Printf.sprintf "/sys/class/net/%s/%s" dev attr
 

networkd/network_server.ml

@@ -27,6 +27,7 @@ type context = unit
 let network_conf = ref "/etc/xcp/network.conf"
 let config : config_t ref = ref empty_config
 let backend_kind = ref Openvswitch
+let enic_workaround_until_version = ref "2.3.0.30"
 
 let legacy_management_interface_start () =
 	try
@@ -85,12 +86,30 @@ let set_dns_interface _ dbg ~name =
 	debug "Setting DNS interface to %s" name;
 	config := {!config with dns_interface = Some name}
 
+(* Returns `true` if vs1 is older than vs2 *)
+let is_older_version vs1 vs2 () =
+	try
+		let list_of_version vs = List.map int_of_string (String.split '.' vs) in
+		let rec loop vs1' vs2' =
+			match vs1', vs2' with
+			| [], _ | _, [] -> false
+			| a :: _, b :: _ when a < b -> true
+			| _ :: tl1, _ :: tl2 -> loop tl1 tl2
+		in
+		loop (list_of_version vs1) (list_of_version vs2)
+	with _ ->
+		warn "Failed to compare driver version.";
+		false
+
 (* The enic driver is for Cisco UCS devices. The current driver adds VLAN0 headers
  * to all incoming packets, which confuses certain guests OSes. The workaround
  * constitutes adding a VLAN0 Linux device to strip those headers again.
  *)
 let need_enic_workaround () =
-	!backend_kind = Bridge && List.mem "enic" (Sysfs.list_drivers ())
+	!backend_kind = Bridge && List.mem "enic" (Sysfs.list_drivers ()) && (!enic_workaround_until_version <> "") && (
+		match Sysfs.get_driver_version "enic" () with
+		| Some vs -> (is_older_version vs !enic_workaround_until_version ())
+		| None -> false )
 
 module Interface = struct
 	let get_config name =

networkd/networkd.ml

@@ -53,9 +53,9 @@ let resources = [
 let options = [
 	"monitor_blacklist", Arg.String (fun x -> Network_monitor_thread.monitor_blacklist := String.split ',' x), (fun () -> String.concat "," !Network_monitor_thread.monitor_blacklist), "List of prefixes of interface names that are not to be monitored";
 	"mac-table-size", Arg.Set_int Network_utils.mac_table_size, (fun () -> string_of_int !Network_utils.mac_table_size), "Default value for the mac-table-size openvswitch parameter (see ovs-vswitchd.conf.db.5)";
+	"enic-workaround-until-version", Arg.Set_string Network_server.enic_workaround_until_version, (fun () -> !Network_server.enic_workaround_until_version), "The version till enic driver workaround will be applied or the version set to an empty string for not applying the workaround.";
 ]
 
-
 let start server =
 	Network_monitor_thread.start ();
 	Network_server.on_startup ();

xcp-networkd.conf

@@ -18,3 +18,6 @@
 
 #The list of prefix interfaces that are not to be monitored
 #monitor-blacklist=dummy,xenbr,xapi,ovs-system,xenapi
+
+# The version till enic driver workaround will be applied or set the version to an empty string for not applying the workaround.
+# enic-workaround-until-version = "2.3.0.30"