CA-408550: XSI-1834: Host netbios name should be added to local hosts file to avoid DNS lookup (xapi-project#6386)

Without adding netbios name into /etc/hosts, a DNS query for localhost
name is performed when talks to Domain Controller.

This waste resources, especially when XenServer is monitorred by
ControllUP, who perform external auth very frequently

Adding netbios name into /etc/hosts to avoid the DNS query and keep
consistent with PBIS

Author: liulinC

ocaml/tests/test_extauth_plugin_ADwinbind.ml

@@ -499,6 +499,106 @@ let test_wbinfo_exception_of_stderr =
   in
   matrix |> List.map @@ fun (inp, exp) -> ("<omit inp>", `Quick, check inp exp)
 
+let test_add_ipv4_localhost_to_hosts =
+  let open Extauth_plugin_ADwinbind in
+  let check inp exp () =
+    let msg =
+      Printf.sprintf "%s -> %s" (String.concat "\n" inp) (String.concat "\n" exp)
+    in
+    let actual =
+      HostsConfIPv4.join ~name:"hostname" ~domain:"domain" ~lines:inp
+    in
+    Alcotest.(check @@ list string) msg exp actual
+  in
+  let matrix =
+    [
+      ( [
+          "127.0.0.1   localhost localhost.localdomain localhost4 \
+           localhost4.localdomain4"
+        ]
+      , [
+          "127.0.0.1   localhost localhost.localdomain localhost4 \
+           localhost4.localdomain4 hostname hostname.domain"
+        ]
+      )
+    ; ( ["127.0.0.1   localhost hostname hostname.domain localhost.localdomain"]
+      , ["127.0.0.1   localhost localhost.localdomain hostname hostname.domain"]
+      )
+    ; ( ["192.168.0.1   some_host"]
+      , ["127.0.0.1 hostname hostname.domain"; "192.168.0.1   some_host"]
+      )
+    ; ([], ["127.0.0.1 hostname hostname.domain"])
+    ]
+  in
+  matrix |> List.map @@ fun (inp, exp) -> ("<omit inp>", `Quick, check inp exp)
+
+let test_add_ipv4_and_ipv6_localhost_to_hosts =
+  let open Extauth_plugin_ADwinbind in
+  let check inp exp () =
+    let msg =
+      Printf.sprintf "%s -> %s" (String.concat "\n" inp) (String.concat "\n" exp)
+    in
+    let actual =
+      HostsConfIPv6.join ~name:"hostname" ~domain:"domain" ~lines:inp
+      |> fun lines ->
+      HostsConfIPv4.join ~name:"hostname" ~domain:"domain" ~lines
+    in
+    Alcotest.(check @@ list string) msg exp actual
+  in
+  let matrix =
+    [
+      ( ["127.0.0.1   localhost"]
+      , [
+          "::1 hostname hostname.domain"
+        ; "127.0.0.1   localhost hostname hostname.domain"
+        ]
+      )
+    ; ( ["127.0.0.1   localhost"; "::1 localhost"]
+      , [
+          "127.0.0.1   localhost hostname hostname.domain"
+        ; "::1 localhost hostname hostname.domain"
+        ]
+      )
+    ; ( []
+      , ["127.0.0.1 hostname hostname.domain"; "::1 hostname hostname.domain"]
+      )
+    ]
+  in
+  matrix |> List.map @@ fun (inp, exp) -> ("<omit inp>", `Quick, check inp exp)
+
+let test_remove_ipv4_localhost_from_hosts =
+  let open Extauth_plugin_ADwinbind in
+  let check inp exp () =
+    let msg =
+      Printf.sprintf "%s -> %s" (String.concat "\n" inp) (String.concat "\n" exp)
+    in
+    let actual =
+      HostsConfIPv4.leave ~name:"hostname" ~domain:"domain" ~lines:inp
+    in
+    Alcotest.(check @@ list string) msg exp actual
+  in
+  let matrix =
+    [
+      ( [
+          "127.0.0.1   localhost localhost.localdomain localhost4 \
+           localhost4.localdomain4"
+        ]
+      , [
+          "127.0.0.1   localhost localhost.localdomain localhost4 \
+           localhost4.localdomain4"
+        ]
+      )
+    ; ( ["127.0.0.1   localhost hostname hostname.domain localhost.localdomain"]
+      , ["127.0.0.1   localhost localhost.localdomain"]
+      )
+    ; (["127.0.0.1   hostname hostname.domain"], [])
+    ; ( ["192.168.0.1   some_host"; "127.0.0.1   localhost hostname"]
+      , ["192.168.0.1   some_host"; "127.0.0.1   localhost"]
+      )
+    ]
+  in
+  matrix |> List.map @@ fun (inp, exp) -> ("<omit inp>", `Quick, check inp exp)
+
 let tests =
   [
     ("ADwinbind:extract_ou_config", ExtractOuConfig.tests)
@@ -512,4 +612,13 @@ let tests =
   ; ( "ADwinbind:test_wbinfo_exception_of_stderr"
     , test_wbinfo_exception_of_stderr
     )
+  ; ( "ADwinbind:test_add_ipv4_localhost_to_hosts"
+    , test_add_ipv4_localhost_to_hosts
+    )
+  ; ( "ADwinbind:test_remove_ipv4_localhost_from_hosts"
+    , test_remove_ipv4_localhost_from_hosts
+    )
+  ; ( "ADwinbind:test_add_ipv4_and_ipv6_localhost_to_hosts"
+    , test_add_ipv4_and_ipv6_localhost_to_hosts
+    )
   ]