ssh: Option unexpectedfun for ssh:daemon and ssh:connect

This option has a fun as value.  The fun will be called when an
unexpected message arrives.  The fun returns either 'skip' or 'report'
to guide the connection_handler what to do.

One usage is to filter out messages that are not wanted in the error
logger as info reports. An example of such a message is the 'etimedout'
tcp error message that will be received if a connection has keep_alive
and the peer is restarted.

1 files changed, 41 insertions, 9 deletions

diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index ab1fc93a1b..e303f02922 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -984,15 +984,38 @@ handle_info({check_cache, _ , _},
 		       #connection{channel_cache = Cache}} = State) ->
     {next_state, StateName, check_cache(State, Cache)};
 
-handle_info(UnexpectedMessage, StateName, #state{ssh_params = SshParams} = State) ->
-    Msg = lists:flatten(io_lib:format(
-           "Unexpected message '~p' received in state '~p'\n"
-           "Role: ~p\n"
-           "Peer: ~p\n"
-           "Local Address: ~p\n", [UnexpectedMessage, StateName,
-               SshParams#ssh.role, SshParams#ssh.peer,
-               proplists:get_value(address, SshParams#ssh.opts)])),
-    error_logger:info_report(Msg),
+handle_info(UnexpectedMessage, StateName, #state{opts = Opts,
+						 ssh_params = SshParams} = State) ->
+    case unexpected_fun(UnexpectedMessage, Opts, SshParams) of
+	report ->
+	    Msg = lists:flatten(
+		    io_lib:format(
+		      "Unexpected message '~p' received in state '~p'\n"
+		      "Role: ~p\n"
+		      "Peer: ~p\n"
+		      "Local Address: ~p\n", [UnexpectedMessage, StateName,
+					      SshParams#ssh.role, SshParams#ssh.peer,
+					      proplists:get_value(address, SshParams#ssh.opts)])),
+	    error_logger:info_report(Msg);
+
+	skip ->
+	    ok;
+
+	Other ->
+	    Msg = lists:flatten(
+		    io_lib:format("Call to fun in 'unexpectedfun' failed:~n"
+				  "Return: ~p\n"
+				  "Message: ~p\n"
+				  "Role: ~p\n"
+				  "Peer: ~p\n"
+				  "Local Address: ~p\n", [Other, UnexpectedMessage, 
+							  SshParams#ssh.role, 
+							  element(2,SshParams#ssh.peer),
+							  proplists:get_value(address, SshParams#ssh.opts)]
+				 )),
+
+	    error_logger:error_report(Msg)
+    end,
     {next_state, StateName, State}.
 
 %%--------------------------------------------------------------------
@@ -1706,6 +1729,15 @@ disconnect_fun(Reason, Opts) ->
 	    catch Fun(Reason)
      end.
 
+unexpected_fun(UnexpectedMessage, Opts, #ssh{peer={_,Peer}}) ->
+    case proplists:get_value(unexpectedfun, Opts) of
+	undefined ->
+	    report;
+	Fun ->
+	    catch Fun(UnexpectedMessage, Peer) 
+    end.
+
+
 check_cache(#state{opts = Opts} = State, Cache) ->
     %% Check the number of entries in Cache
     case proplists:get_value(size, ets:info(Cache)) of