[snmp|test] Improved IPv6 test checks

Improve the checks for if/when we shall run the IPv6
test cases.

OTP-15764

4 files changed, 78 insertions, 41 deletions

diff --git a/lib/snmp/test/snmp_agent_test.erl b/lib/snmp/test/snmp_agent_test.erl
index fa7db87c38..860ca17cdb 100644
--- a/lib/snmp/test/snmp_agent_test.erl
+++ b/lib/snmp/test/snmp_agent_test.erl
@@ -687,24 +687,18 @@ init_per_group_ipv6(GroupName, Config, Init) ->
         true ->
             {skip, "Host *may* not *properly* support IPV6"};
         false ->
-            %% And now for the "proper" test...
-            case ct:require(ipv6_hosts) of
-                ok ->
-                    {ok, Hostname0} = inet:gethostname(),
-                    case lists:member(list_to_atom(Hostname0),
-                                      ct:get_config(ipv6_hosts)) of
-                        true ->
-                            Init(
-                              snmp_test_lib:init_group_top_dir(
-                                GroupName,
-                                [{ipfamily, inet6},
-                                 {ip, ?LOCALHOST(inet6)}
-                                 | lists:keydelete(ip, 1, Config)]));
-                        false ->
-                            {skip, "Host does not support IPV6"}
-                    end;
-                _ ->
-                    {skip, "Test config ipv6_hosts is missing"}
+            %% Even if this host supports IPv6 we don't use it unless its
+            %% one of the configured/supported IPv6 hosts...
+            case (?HAS_SUPPORT_IPV6() andalso ?IS_IPV6_HOST()) of
+                true ->
+                    Init(
+                      snmp_test_lib:init_group_top_dir(
+                        GroupName,
+                        [{ipfamily, inet6},
+                         {ip, ?LOCALHOST(inet6)}
+                         | lists:keydelete(ip, 1, Config)]));
+                false ->
+                    {skip, "Host does not support IPv6"}
             end
     end.
 
diff --git a/lib/snmp/test/snmp_manager_test.erl b/lib/snmp/test/snmp_manager_test.erl
index 8fd325192b..d959d9e09b 100644
--- a/lib/snmp/test/snmp_manager_test.erl
+++ b/lib/snmp/test/snmp_manager_test.erl
@@ -649,22 +649,17 @@ init_per_group_ipv6(GroupName, Config) ->
         true ->
             {skip, "Host *may* not *properly* support IPV6"};
         false ->
-            {ok, Hostname} = inet:gethostname(),
-            case ct:require(ipv6_hosts) of
-                ok ->
-                    case lists:member(list_to_atom(Hostname),
-                                      ct:get_config(ipv6_hosts)) of
-                        true ->
-                            ipv6_init(snmp_test_lib:init_group_top_dir(GroupName, 
-                                                                       Config));
-                        false ->
-                            {skip, "Host does not support IPv6"}
-                    end;
-                _ ->
-                    {skip, "Test config ipv6_hosts is missing"}
+            %% Even if this host supports IPv6 we don't use it unless its
+            %% one of the configures/supported IPv6 hosts...
+            case (?HAS_SUPPORT_IPV6() andalso ?IS_IPV6_HOST()) of
+                true ->
+                    ipv6_init(snmp_test_lib:init_group_top_dir(GroupName, Config));
+                false ->
+                    {skip, "Host does not support IPv6"}
             end
     end.
-    
+
+
 end_per_group(_GroupName, Config) ->
     %% Do we really need to do this?
     lists:keydelete(snmp_group_top_dir, 1, Config).
diff --git a/lib/snmp/test/snmp_test_lib.erl b/lib/snmp/test/snmp_test_lib.erl
index 9fab1a5c56..42f710e4cd 100644
--- a/lib/snmp/test/snmp_test_lib.erl
+++ b/lib/snmp/test/snmp_test_lib.erl
@@ -25,7 +25,9 @@
 
 -export([hostname/0, hostname/1, localhost/0, localhost/1, os_type/0, sz/1,
 	 display_suite_info/1]).
--export([non_pc_tc_maybe_skip/4, os_based_skip/1]).
+-export([non_pc_tc_maybe_skip/4, os_based_skip/1,
+         has_support_ipv6/0, has_support_ipv6/1,
+         is_ipv6_host/0, is_ipv6_host/1]).
 -export([fix_data_dir/1, 
 	 init_suite_top_dir/2, init_group_top_dir/2, init_testcase_top_dir/2, 
 	 lookup/2, 
@@ -52,11 +54,12 @@ hostname() ->
     hostname(node()).
 
 hostname(Node) ->
-    from($@, atom_to_list(Node)).
-
-from(H, [H | T]) -> T;
-from(H, [_ | T]) -> from(H, T);
-from(_H, []) -> [].
+    case string:tokens(atom_to_list(Node), [$@]) of
+        [_, Host] ->
+            Host;
+        _ ->
+            []
+    end.
 
 %% localhost() ->
 %%     {ok, Ip} = snmp_misc:ip(net_adm:localhost()),
@@ -78,7 +81,9 @@ localhost(Family) ->
                 {error, Reason1} ->
                     fail({getifaddrs, Reason1}, ?MODULE, ?LINE)
             end;
-        {ok, {0, _, _, _, _, _, _, _}} when (Family =:= inet6) ->
+        {ok, {A1, _, _, _, _, _, _, _}} when (Family =:= inet6) andalso
+                                             ((A1 =:= 0) orelse
+                                              (A1 =:= 16#fe80)) ->
             %% Ouch, we need to use something else
             case inet:getifaddrs() of
                 {ok, IfList} ->
@@ -270,8 +275,47 @@ os_based_skip_check(OsName, OsNames) ->
 	_ ->
 	    false
     end.
+
+
+%% A basic test to check if current host supports IPv6
+has_support_ipv6() ->
+    case inet:gethostname() of
+        {ok, Hostname} ->
+            has_support_ipv6(Hostname);
+        _ ->
+            false
+    end.
+
+has_support_ipv6(Hostname) ->
+    case inet:getaddr(Hostname, inet6) of
+        {ok, Addr} when (size(Addr) =:= 8) andalso
+                        (element(1, Addr) =/= 0) andalso
+                        (element(1, Addr) =/= 16#fe80) ->
+            true;
+        {ok, _} ->
+            false;
+        {error, _} ->
+            false
+    end.
 		
 
+is_ipv6_host() ->
+    case inet:gethostname() of
+        {ok, Hostname} ->
+            is_ipv6_host(Hostname);
+        {error, _} ->
+            false
+    end.
+
+is_ipv6_host(Hostname) ->
+    case ct:require(ipv6_hosts) of
+        ok ->
+            lists:member(list_to_atom(Hostname), ct:get_config(ipv6_hosts));
+        _ ->
+            false
+    end.
+
+
 %% ----------------------------------------------------------------
 %% Test suite utility functions
 %% 
diff --git a/lib/snmp/test/snmp_test_lib.hrl b/lib/snmp/test/snmp_test_lib.hrl
index dafa4cbf19..c66602b779 100644
--- a/lib/snmp/test/snmp_test_lib.hrl
+++ b/lib/snmp/test/snmp_test_lib.hrl
@@ -49,8 +49,12 @@
         snmp_test_lib:os_based_skip(Skippable)).
 -define(NON_PC_TC_MAYBE_SKIP(Config, Condition),
         snmp_test_lib:non_pc_tc_maybe_skip(Config, Condition, ?MODULE, ?LINE)).
--define(SKIP(Reason),   snmp_test_lib:skip(Reason, ?MODULE, ?LINE)).
--define(FAIL(Reason),   snmp_test_lib:fail(Reason, ?MODULE, ?LINE)).
+-define(SKIP(Reason),        snmp_test_lib:skip(Reason, ?MODULE, ?LINE)).
+-define(FAIL(Reason),        snmp_test_lib:fail(Reason, ?MODULE, ?LINE)).
+-define(IS_IPV6_HOST(),      snmp_test_lib:is_ipv6_host()).
+-define(IS_IPV6_HOST(H),     snmp_test_lib:is_ipv6_host(H)).
+-define(HAS_SUPPORT_IPV6(),  snmp_test_lib:has_support_ipv6()).
+-define(HAS_SUPPORT_IPV6(H), snmp_test_lib:has_support_ipv6(H)).
 
 
 %% - Time macros -