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.

4 files changed, 146 insertions, 10 deletions

diff --git a/lib/ssh/doc/src/ssh.xml b/lib/ssh/doc/src/ssh.xml
index 5402d91e03..b39ca0852c 100644
--- a/lib/ssh/doc/src/ssh.xml
+++ b/lib/ssh/doc/src/ssh.xml
@@ -180,6 +180,14 @@
 	    <p>Provides a fun to implement your own logging when a server disconnects the client.</p>
 	  </item>
 
+	  <tag><c><![CDATA[{unexpectedfun, fun(Message:term(), Peer) -> report | skip }]]></c></tag>
+	  <item>
+	    <p>Provides a fun to implement your own logging or other action when an unexpected message arrives.
+	    If the fun returns <c>report</c> the usual info report is issued but if <c>skip</c> is returned no
+	    report is generated.</p>
+	    <p><c>Peer</c> is in the format of <c>{Host,Port}</c>.</p>
+	  </item>
+
 	  <tag><c><![CDATA[{public_key_alg, 'ssh-rsa' | 'ssh-dss'}]]></c></tag>
 	  <item>
 	    <note>
@@ -532,6 +540,14 @@ kex is implicit but public_key is set explicitly.</p>
 	    <p>Provides a fun to implement your own logging when a user disconnects from the server.</p>
 	  </item>
 
+	  <tag><c><![CDATA[{unexpectedfun, fun(Message:term(), Peer) -> report | skip }]]></c></tag>
+	  <item>
+	    <p>Provides a fun to implement your own logging or other action when an unexpected message arrives.
+	    If the fun returns <c>report</c> the usual info report is issued but if <c>skip</c> is returned no
+	    report is generated.</p>
+	    <p><c>Peer</c> is in the format of <c>{Host,Port}</c>.</p>
+	  </item>
+
 	  <tag><c><![CDATA[{ssh_msg_debug_fun, fun(ConnectionRef::ssh_connection_ref(), AlwaysDisplay::boolean(), Msg::binary(), LanguageTag::binary()) -> _}]]></c></tag>
 	  <item>
 	    <p>Provide a fun to implement your own logging of the SSH message SSH_MSG_DEBUG. The last three parameters are from the message, see RFC4253, section 11.3. The <c>ConnectionRef</c> is the reference to the connection on which the message arrived. The return value from the fun is not checked.</p>
diff --git a/lib/ssh/src/ssh.erl b/lib/ssh/src/ssh.erl
index 826c585d65..86c042781c 100644
--- a/lib/ssh/src/ssh.erl
+++ b/lib/ssh/src/ssh.erl
@@ -345,6 +345,8 @@ handle_option([{connectfun, _} = Opt | Rest], SocketOptions, SshOptions) ->
     handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
 handle_option([{disconnectfun, _} = Opt | Rest], SocketOptions, SshOptions) ->
     handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
+handle_option([{unexpectedfun, _} = Opt | Rest], SocketOptions, SshOptions) ->
+    handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
 handle_option([{failfun, _} = Opt | Rest],  SocketOptions, SshOptions) ->
     handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
 handle_option([{ssh_msg_debug_fun, _} = Opt | Rest],  SocketOptions, SshOptions) ->
@@ -450,7 +452,9 @@ handle_ssh_option({infofun, Value} = Opt)  when is_function(Value) ->
     Opt;
 handle_ssh_option({connectfun, Value} = Opt) when is_function(Value) ->
     Opt;
-handle_ssh_option({disconnectfun , Value} = Opt) when is_function(Value) ->
+handle_ssh_option({disconnectfun, Value} = Opt) when is_function(Value) ->
+    Opt;
+handle_ssh_option({unexpectedfun, Value} = Opt) when is_function(Value,2) ->
     Opt;
 handle_ssh_option({failfun, Value} = Opt) when is_function(Value) ->
     Opt;
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
diff --git a/lib/ssh/test/ssh_basic_SUITE.erl b/lib/ssh/test/ssh_basic_SUITE.erl
index f737c436c8..b3a837f40f 100644
--- a/lib/ssh/test/ssh_basic_SUITE.erl
+++ b/lib/ssh/test/ssh_basic_SUITE.erl
@@ -60,6 +60,8 @@ all() ->
      ssh_msg_debug_fun_option_server,
      disconnectfun_option_server,
      disconnectfun_option_client,
+     unexpectedfun_option_server,
+     unexpectedfun_option_client,
      preferred_algorithms,
      id_string_no_opt_client,
      id_string_own_string_client,
@@ -879,6 +881,88 @@ disconnectfun_option_client(Config) ->
     end.
 
 %%--------------------------------------------------------------------
+unexpectedfun_option_server(Config) ->
+    PrivDir = ?config(priv_dir, Config),
+    UserDir = filename:join(PrivDir, nopubkey), % to make sure we don't use public-key-auth
+    file:make_dir(UserDir),
+    SysDir = ?config(data_dir, Config),
+
+    Parent = self(),
+    ConnFun = fun(_,_,_) -> Parent ! {connection_pid,self()} end,
+    UnexpFun = fun(Msg,Peer) ->
+		       Parent ! {unexpected,Msg,Peer,self()},
+		       skip
+	       end,
+
+    {Pid, Host, Port} = ssh_test_lib:daemon([{system_dir, SysDir},
+					     {user_dir, UserDir},
+					     {password, "morot"},
+					     {failfun, fun ssh_test_lib:failfun/2},
+					     {connectfun, ConnFun},
+					     {unexpectedfun, UnexpFun}]),
+    _ConnectionRef =
+	ssh_test_lib:connect(Host, Port, [{silently_accept_hosts, true},
+					  {user, "foo"},
+					  {password, "morot"},
+					  {user_dir, UserDir},
+					  {user_interaction, false}]),
+    receive
+	{connection_pid,Server} ->
+	    %% Beware, implementation knowledge:
+	    Server ! unexpected_message,
+	    receive
+		{unexpected, unexpected_message, {{_,_,_,_},_}, _} -> ok;
+		{unexpected, unexpected_message, Peer, _} -> ct:fail("Bad peer ~p",[Peer]);
+		M = {unexpected, _, _, _} -> ct:fail("Bad msg ~p",[M])
+	    after 3000 ->
+		    ssh:stop_daemon(Pid),
+		    {fail,timeout2}
+	    end
+    after 3000 ->
+	    ssh:stop_daemon(Pid),
+	    {fail,timeout1}
+    end.
+
+%%--------------------------------------------------------------------
+unexpectedfun_option_client(Config) ->
+    PrivDir = ?config(priv_dir, Config),
+    UserDir = filename:join(PrivDir, nopubkey), % to make sure we don't use public-key-auth
+    file:make_dir(UserDir),
+    SysDir = ?config(data_dir, Config),
+
+    Parent = self(),
+    UnexpFun = fun(Msg,Peer) -> 
+		       Parent ! {unexpected,Msg,Peer,self()},
+		       skip
+	       end,
+
+    {Pid, Host, Port} = ssh_test_lib:daemon([{system_dir, SysDir},
+					     {user_dir, UserDir},
+					     {password, "morot"},
+					     {failfun, fun ssh_test_lib:failfun/2}]),
+    ConnectionRef =
+	ssh_test_lib:connect(Host, Port, [{silently_accept_hosts, true},
+					  {user, "foo"},
+					  {password, "morot"},
+					  {user_dir, UserDir},
+					  {user_interaction, false},
+					  {unexpectedfun, UnexpFun}]),
+    %% Beware, implementation knowledge:
+    ConnectionRef ! unexpected_message,
+
+    receive
+	{unexpected, unexpected_message, {{_,_,_,_},_}, ConnectionRef} ->
+	    ok;
+	{unexpected, unexpected_message, Peer, ConnectionRef} ->
+	    ct:fail("Bad peer ~p",[Peer]);
+	M = {unexpected, _, _, _} ->
+	    ct:fail("Bad msg ~p",[M])
+    after 3000 ->
+	    ssh:stop_daemon(Pid),
+	    {fail,timeout}
+    end.
+
+%%--------------------------------------------------------------------
 known_hosts() ->
     [{doc, "check that known_hosts is updated correctly"}].
 known_hosts(Config) when is_list(Config) ->