Do not apply IPv6 config if IPv6 is disabled

Any exceptions from this were ignored anyway, but this again avoids scary
messages in the logs.

Signed-off-by: Rob Hoes <[email protected]>

Author: robhoes

lib/network_utils.ml

@@ -901,6 +901,13 @@ module Proc = struct
   let get_bond_links_up name =
     let statusses = get_bond_slave_info name "MII Status" in
     List.fold_left (fun x (_, y) -> x + (if y = "up" then 1 else 0)) 0 statusses
+
+  let get_ipv6_disabled () =
+    try
+      Unixext.string_of_file "/proc/sys/net/ipv6/conf/all/disable_ipv6"
+      |> String.trim
+      |> (=) "1"
+    with _ -> false
 end
 
 module Ovs = struct

networkd/network_server.ml

@@ -323,6 +323,9 @@ module Interface = struct
 
   let set_ipv6_conf _ dbg ~name ~conf =
     Debug.with_thread_associated dbg (fun () ->
+      if Proc.get_ipv6_disabled () then
+        warn "Not configuring IPv6 address for %s (IPv6 is disabled)" name
+      else begin
         debug "Configuring IPv6 address for %s: %s" name (conf |> Rpcmarshal.marshal typ_of_ipv6 |> Jsonrpc.to_string);
         update_config name {(get_config name) with ipv6_conf = conf};
         match conf with
@@ -371,6 +374,7 @@ module Interface = struct
           let add_addrs = Xapi_stdext_std.Listext.List.set_difference addrs cur_addrs in
           List.iter (Ip.del_ip_addr name) rm_addrs;
           List.iter (Ip.set_ip_addr name) add_addrs
+      end
       ) ()
 
   let get_ipv6_gateway _ dbg ~name =
@@ -385,13 +389,17 @@ module Interface = struct
 
   let set_ipv6_gateway _ dbg ~name ~address =
     Debug.with_thread_associated dbg (fun () ->
+      if Proc.get_ipv6_disabled () then
+        warn "Not configuring IPv6 gateway for %s (IPv6 is disabled)" name
+      else begin
         debug "Configuring IPv6 gateway for %s: %s" name (Unix.string_of_inet_addr address);
         update_config name {(get_config name) with ipv6_gateway = Some address};
         if !config.gateway_interface = None || !config.gateway_interface = Some name then begin
           debug "%s is the default gateway interface" name;
           Ip.set_gateway name address
         end else
           debug "%s is NOT the default gateway interface" name
+      end
       ) ()
 
   let set_ipv4_routes _ dbg ~name ~routes =