ssh: Document and clean up SSH behaviours

16 files changed, 275 insertions, 110 deletions

diff --git a/lib/ssh/src/Makefile b/lib/ssh/src/Makefile
index b8eecd3fa2..323f0af191 100644
--- a/lib/ssh/src/Makefile
+++ b/lib/ssh/src/Makefile
@@ -41,7 +41,9 @@ RELSYSDIR = $(RELEASE_PATH)/lib/ssh-$(VSN)
 BEHAVIOUR_MODULES= \
 	ssh_sftpd_file_api \
         ssh_channel \
-	ssh_key_api
+	ssh_subsystem \
+	ssh_client_key_api \
+	ssh_server_key_api
 
 MODULES= \
 	ssh \
diff --git a/lib/ssh/src/ssh.app.src b/lib/ssh/src/ssh.app.src
index a96c1a510c..a0ba7cf7d9 100644
--- a/lib/ssh/src/ssh.app.src
+++ b/lib/ssh/src/ssh.app.src
@@ -10,6 +10,7 @@
 	     ssh_auth,
 	     ssh_bits,
 	     ssh_cli,
+             ssh_client_key_api,
 	     ssh_channel,
 	     ssh_channel_sup,
 	     ssh_connection,
@@ -21,13 +22,14 @@
 	     sshd_sup,
 	     ssh_file,
 	     ssh_io,
-             ssh_key_api,
 	     ssh_math,
 	     ssh_no_io,
+             ssh_server_key_api,
 	     ssh_sftp,
 	     ssh_sftpd,
 	     ssh_sftpd_file,
 	     ssh_sftpd_file_api,
+	     ssh_subsystem,
 	     ssh_subsystem_sup,
 	     ssh_sup,
 	     ssh_system_sup,
diff --git a/lib/ssh/src/ssh.erl b/lib/ssh/src/ssh.erl
index f163539e75..a3ba8148eb 100644
--- a/lib/ssh/src/ssh.erl
+++ b/lib/ssh/src/ssh.erl
@@ -80,7 +80,7 @@ connect(Host, Port, Options, Timeout) ->
 	{error, _Reason} = Error ->
 	    Error;
 	{SocketOptions, SshOptions} ->
-	    DisableIpv6 =  proplists:get_value(ip_v6_disabled, SshOptions, false),
+	    DisableIpv6 =  proplists:get_value(ipv6_disabled, SshOptions, false),
 	    Inet = inetopt(DisableIpv6),
 	    do_connect(Host, Port, [Inet | SocketOptions], 
 		       [{user_pid, self()}, {host, Host} | fix_idle_time(SshOptions)], Timeout, DisableIpv6)
@@ -173,7 +173,7 @@ daemon(HostAddr, Port, Options0) ->
 		   _ ->
 		       Options0
 	       end,
-    DisableIpv6 =  proplists:get_value(ip_v6_disabled, Options0, false),
+    DisableIpv6 =  proplists:get_value(ipv6_disabled, Options0, false),
     {Host, Inet, Options} = case HostAddr of
 				any ->
 				    {ok, Host0} = inet:gethostname(), 
@@ -346,7 +346,10 @@ handle_option([{disconnectfun, _} = 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([{ip_v6_disabled, _} = Opt | Rest], SocketOptions, SshOptions) ->
+%%Backwards compatibility should not be underscore between ip and v6 in API
+handle_option([{ip_v6_disabled, Value} | Rest], SocketOptions, SshOptions) ->
+    handle_option(Rest, SocketOptions, [handle_ssh_option({ipv6_disabled, Value}) | SshOptions]);
+handle_option([{ipv6_disabled, _} = Opt | Rest], SocketOptions, SshOptions) ->
     handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
 handle_option([{transport, _} = Opt | Rest], SocketOptions, SshOptions) ->
     handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
@@ -379,10 +382,14 @@ handle_ssh_option({silently_accept_hosts, Value} = Opt) when Value == true; Valu
     Opt;
 handle_ssh_option({user_interaction, Value} = Opt) when Value == true; Value == false ->
     Opt;
-handle_ssh_option({public_key_alg, Value} = Opt) when Value == ssh_rsa; Value == ssh_dsa ->
+handle_ssh_option({public_key_alg, ssh_dsa}) ->
+    {public_key_alg, 'ssh-dss'};
+handle_ssh_option({public_key_alg, ssh_rsa})  ->
+    {public_key_alg, 'ssh-rsa'};
+handle_ssh_option({public_key_alg, Value} = Opt) when Value == 'ssh-rsa'; Value == 'ssh-dss' ->
     Opt;
 handle_ssh_option({pref_public_key_algs, Value} = Opt) when is_list(Value), length(Value) >= 1 ->
-    case check_pref_algs(Value) of
+    case handle_pref_algs(Value, []) of
 	true ->
 	    Opt;
 	_ ->
@@ -420,7 +427,9 @@ handle_ssh_option({disconnectfun , Value} = Opt) when is_function(Value) ->
     Opt;
 handle_ssh_option({failfun, Value} = Opt) when is_function(Value) ->
     Opt;
-handle_ssh_option({ip_v6_disabled, Value} = Opt) when is_boolean(Value) ->
+
+handle_ssh_option({ipv6_disabled, Value} = Opt) when Value == true;
+						      Value == false ->
     Opt;
 handle_ssh_option({transport, {Protocol, Cb, ClosTag}} = Opt) when is_atom(Protocol),
 								   is_atom(Cb),
@@ -448,7 +457,7 @@ handle_inet_option({active, _} = Opt) ->
 		   "and activ is handled internaly user is not allowd"
 		   "to specify this option"}});
 handle_inet_option({inet, _} = Opt) ->
-    throw({error, {{eoptions, Opt},"Is set internaly use ip_v6_disabled to"
+    throw({error, {{eoptions, Opt},"Is set internaly use ipv6_disabled to"
 		   " enforce iv4 in the server, client will fallback to ipv4 if"
 		   " it can not use ipv6"}});
 handle_inet_option({reuseaddr, _} = Opt) ->
@@ -458,14 +467,18 @@ handle_inet_option({reuseaddr, _} = Opt) ->
 handle_inet_option(Opt) ->
     Opt.
 %% Check preferred algs
-check_pref_algs([]) ->
-    true;
-check_pref_algs([H|T]) ->
+handle_pref_algs([], Acc) ->
+    {true, lists:reverse(Acc)};
+handle_pref_algs([H|T], Acc) ->
     case H of
 	ssh_dsa ->
-	    check_pref_algs(T);
+	    handle_pref_algs(T, ['ssh-dss'| Acc]);
 	ssh_rsa ->
-	    check_pref_algs(T);
+	    handle_pref_algs(T, ['ssh-rsa'| Acc]);
+	'ssh-dss' ->
+	    handle_pref_algs(T, ['ssh-dss'| Acc]);
+	'ssh-rsa' ->
+	    handle_pref_algs(T, ['ssh-rsa'| Acc]);
 	_ ->
 	    false
     end.
diff --git a/lib/ssh/src/ssh_auth.erl b/lib/ssh/src/ssh_auth.erl
index c436793dc4..cb0c7751f0 100644
--- a/lib/ssh/src/ssh_auth.erl
+++ b/lib/ssh/src/ssh_auth.erl
@@ -48,17 +48,18 @@ publickey_msg([Alg, #ssh{user = User,
 
     case KeyCb:user_key(Alg, Opts) of
 	{ok, Key} ->
+	    StrAlgo = algorithm_string(Alg),
 	    PubKeyBlob = encode_public_key(Key),
 	    SigData = build_sig_data(SessionId, 
-				     User, Service, PubKeyBlob, Alg),
+				     User, Service, PubKeyBlob, StrAlgo),
 	    Sig = ssh_transport:sign(SigData, Hash, Key),
-	    SigBlob = list_to_binary([?string(Alg), ?binary(Sig)]),
+	    SigBlob = list_to_binary([?string(StrAlgo), ?binary(Sig)]),
 	    ssh_transport:ssh_packet(
 	      #ssh_msg_userauth_request{user = User,
 					service = Service,
 					method = "publickey",
 					data = [?TRUE,
-						?string(Alg),
+						?string(StrAlgo),
 						?binary(PubKeyBlob),
 						?binary(SigBlob)]},
 	      Ssh);
@@ -120,8 +121,7 @@ init_userauth_request_msg(#ssh{opts = Opts} = Ssh) ->
 					    data = <<>>},
 	    case proplists:get_value(pref_public_key_algs, Opts, false) of
 		false ->
-		    FirstAlg = algorithm(proplists:get_value(public_key_alg, Opts,
-							     ?PREFERRED_PK_ALG)),
+		    FirstAlg = proplists:get_value(public_key_alg, Opts, ?PREFERRED_PK_ALG),
 		    SecondAlg = other_alg(FirstAlg),
 		    AllowUserInt =  proplists:get_value(user_interaction, Opts, true),
 		    Prefs = method_preference(FirstAlg, SecondAlg, AllowUserInt),
@@ -130,7 +130,7 @@ init_userauth_request_msg(#ssh{opts = Opts} = Ssh) ->
 							  userauth_methods = none,
 							  service = "ssh-connection"});
 		Algs ->
-		    FirstAlg = algorithm(lists:nth(1, Algs)),
+		    FirstAlg = lists:nth(1, Algs),
 		    case length(Algs) =:= 2 of
 			true ->
 			    SecondAlg = other_alg(FirstAlg),
@@ -358,7 +358,7 @@ verify_sig(SessionId, User, Service, Alg, KeyBlob, SigWLen, Opts) ->
     {ok, Key} = decode_public_key_v2(KeyBlob, Alg),
     KeyCb =  proplists:get_value(key_cb, Opts, ssh_file),
 
-    case KeyCb:is_auth_key(Key, User, Alg, Opts) of
+    case KeyCb:is_auth_key(Key, User, Opts) of
 	true ->
 	    PlainText = build_sig_data(SessionId, User,
 				       Service, KeyBlob, Alg),
@@ -381,9 +381,9 @@ build_sig_data(SessionId, User, Service, KeyBlob, Alg) ->
 	   ?binary(KeyBlob)],
     list_to_binary(Sig).
 
-algorithm(ssh_rsa) ->
+algorithm_string('ssh-rsa') ->
     "ssh-rsa";
-algorithm(ssh_dsa) ->
+algorithm_string('ssh-dss') ->
      "ssh-dss".
 
 decode_keyboard_interactive_prompts(NumPrompts, Data) ->
@@ -457,10 +457,10 @@ userauth_pk_messages() ->
 	binary]} % key blob
      ].
 
-other_alg("ssh-rsa") ->
-    "ssh-dss";
-other_alg("ssh-dss") ->
-    "ssh-rsa".
+other_alg('ssh-rsa') ->
+    'ssh-dss';
+other_alg('ssh-dss') ->
+    'ssh-rsa'.
 decode_public_key_v2(K_S, "ssh-rsa") ->
     case ssh_bits:decode(K_S,[string,mpint,mpint]) of
 	["ssh-rsa", E, N] ->
diff --git a/lib/ssh/src/ssh_auth.hrl b/lib/ssh/src/ssh_auth.hrl
index e74ee10041..6cd8e6bf14 100644
--- a/lib/ssh/src/ssh_auth.hrl
+++ b/lib/ssh/src/ssh_auth.hrl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2008-2010. All Rights Reserved.
+%% Copyright Ericsson AB 2008-2012. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -23,7 +23,7 @@
 
 -define(SUPPORTED_AUTH_METHODS, "publickey,keyboard-interactive,password").
 
--define(PREFERRED_PK_ALG, ssh_rsa).
+-define(PREFERRED_PK_ALG, 'ssh-rsa').
 
 -define(SSH_MSG_USERAUTH_REQUEST,  50).
 -define(SSH_MSG_USERAUTH_FAILURE,  51).
diff --git a/lib/ssh/src/ssh_channel.erl b/lib/ssh/src/ssh_channel.erl
index 1938858420..4e8f8538c2 100644
--- a/lib/ssh/src/ssh_channel.erl
+++ b/lib/ssh/src/ssh_channel.erl
@@ -23,14 +23,35 @@
 
 -include("ssh_connect.hrl").
 
-%%% Optional callbacks handle_call/3, handle_cast/2, handle_msg/2,
-%%% code_change/3
-%% Should be further specified later
--callback init(Options::list()) ->
-    {ok, State::term()} | {ok, State::term(), Timeout::timeout()} | 
-    {stop, Reason ::term()}. 
-
--callback terminate(term(), term()) -> term().
+-callback init(Args :: term()) ->
+    {ok, State :: term()} | {ok, State :: term(), timeout() | hibernate} |
+    {stop, Reason :: term()} | ignore.
+-callback handle_call(Request :: term(), From :: {pid(), Tag :: term()},
+                      State :: term()) ->
+    {reply, Reply :: term(), NewState :: term()} |
+    {reply, Reply :: term(), NewState :: term(), timeout() | hibernate} |
+    {noreply, NewState :: term()} |
+    {noreply, NewState :: term(), timeout() | hibernate} |
+    {stop, Reason :: term(), Reply :: term(), NewState :: term()} |
+    {stop, Reason :: term(), NewState :: term()}.
+-callback handle_cast(Request :: term(), State :: term()) ->
+    {noreply, NewState :: term()} |
+    {noreply, NewState :: term(), timeout() | hibernate} |
+    {stop, Reason :: term(), NewState :: term()}.
+
+-callback terminate(Reason :: (normal | shutdown | {shutdown, term()} |
+                               term()),
+                    State :: term()) ->
+    term().
+-callback code_change(OldVsn :: (term() | {down, term()}), State :: term(),
+                      Extra :: term()) ->
+    {ok, NewState :: term()} | {error, Reason :: term()}.
+
+-callback handle_msg(Msg ::term(), State :: term()) ->
+    {noreply, NewState :: term()} |
+    {noreply, NewState :: term(), timeout() | hibernate} |
+    {stop, Reason :: term(), NewState :: term()}.
+
 
 -callback handle_ssh_msg({ssh_cm, ConnectionRef::term(), SshMsg::term()}, 
  			 State::term()) -> {ok, State::term()} | 
diff --git a/lib/ssh/src/ssh_client_key.erl b/lib/ssh/src/ssh_client_key.erl
new file mode 100644
index 0000000000..2c48884dc2
--- /dev/null
+++ b/lib/ssh/src/ssh_client_key.erl
@@ -0,0 +1,34 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2011-2012. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(ssh_client_key).
+
+-include_lib("public_key/include/public_key.hrl").
+-include("ssh.hrl").
+
+-callback is_host_key(Key :: public_key(), Host :: string(),
+		      Algorithm :: 'ssh-rsa'| 'ssh-dsa'| atom(), Options :: proplists:proplist()) ->
+    boolean().
+
+-callback user_key(Algorithm ::  'ssh-rsa'| 'ssh-dsa'| atom(), Options :: list()) ->
+    {ok,  PrivateKey :: term()} | {error, string()}.
+
+
+-callback add_host_key(Host :: string(), PublicKey :: term(), Options :: list()) ->
+    ok | {error, Error::term()}.
diff --git a/lib/ssh/src/ssh_client_key_api.erl b/lib/ssh/src/ssh_client_key_api.erl
new file mode 100644
index 0000000000..eed0b85f47
--- /dev/null
+++ b/lib/ssh/src/ssh_client_key_api.erl
@@ -0,0 +1,35 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2011-2012. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(ssh_client_key_api).
+
+-include_lib("public_key/include/public_key.hrl").
+-include("ssh.hrl").
+
+-callback is_host_key(PublicKey :: #'RSAPublicKey'{}| {integer(),  #'Dss-Parms'{}}| term() , Host :: string(),
+		      Algorithm :: 'ssh-rsa'| 'ssh-dss'| atom(), ConnectOptions :: proplists:proplist()) ->
+    boolean().
+
+-callback user_key(Algorithm ::  'ssh-rsa'| 'ssh-dss'| atom(), ConnectOptions :: proplists:proplists()) ->
+    {ok,  PrivateKey :: #'RSAPrivateKey'{}| #'DSAPrivateKey'{} |  term()} | {error, string()}.
+
+
+-callback add_host_key(Host :: string(), PublicKey ::  #'RSAPublicKey'{}| {integer(),  #'Dss-Parms'{}}| term(),
+		       Options :: list()) ->
+    ok | {error, Error::term()}.
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index d8950a7b67..b79e8530b7 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -749,9 +749,9 @@ extract_algs([], NewList) ->
     lists:reverse(NewList);
 extract_algs([H|T], NewList) ->
     case H of
-	ssh_dsa ->
+	'ssh-dss' ->
 	    extract_algs(T, ["ssh-dss"|NewList]);
-	ssh_rsa -> 
+	'ssh-rsa' ->
 	    extract_algs(T, ["ssh-rsa"|NewList])
     end.
 available_host_key(KeyCb, "ssh-dss"= Alg, Opts) ->
diff --git a/lib/ssh/src/ssh_file.erl b/lib/ssh/src/ssh_file.erl
index a6b82a7a13..f115a32710 100644
--- a/lib/ssh/src/ssh_file.erl
+++ b/lib/ssh/src/ssh_file.erl
@@ -23,7 +23,8 @@
 
 -module(ssh_file).
 
--behaviour(ssh_key_api).
+-behaviour(ssh_server_key_api).
+-behaviour(ssh_client_key_api).
 
 -include_lib("public_key/include/public_key.hrl").
 -include_lib("kernel/include/file.hrl").
@@ -34,7 +35,7 @@
 	 user_key/2,
 	 is_host_key/4,
 	 add_host_key/3,
-	 is_auth_key/4]).
+	 is_auth_key/3]).
 
 
 -define(PERM_700, 8#700).
@@ -53,8 +54,8 @@ host_key(Algorithm, Opts) ->
     decode(File, Password).
 
 
-is_auth_key(Key, User, Alg, Opts) ->
-    case lookup_user_key(Key, User, Alg, Opts) of
+is_auth_key(Key, User,Opts) ->
+    case lookup_user_key(Key, User, Opts) of
 	{ok, Key} ->
 	    true;
 	_ ->
@@ -138,13 +139,13 @@ add_host_key(Host, Key, Opts) ->
    	    Error
     end.
 
-lookup_user_key(Key, User, Alg, Opts) ->
+lookup_user_key(Key, User, Opts) ->
     SshDir = ssh_dir({remoteuser,User}, Opts),
-    case lookup_user_key_f(Key, User, SshDir, Alg, "authorized_keys", Opts) of
+    case lookup_user_key_f(Key, User, SshDir, "authorized_keys", Opts) of
 	{ok, Key} ->
 	    {ok, Key};
 	_ ->
-	    lookup_user_key_f(Key, User, SshDir, Alg,  "authorized_keys2", Opts)
+	    lookup_user_key_f(Key, User, SshDir, "authorized_keys2", Opts)
     end.
 
 
@@ -213,9 +214,9 @@ do_lookup_host_key(Host, Alg, Opts) ->
 	Error -> Error
     end.
 
-identity_key_filename("ssh-dss") ->
+identity_key_filename('ssh-dss') ->
     "id_dsa";
-identity_key_filename("ssh-rsa") ->
+identity_key_filename('ssh-rsa') ->
     "id_rsa".
 
 identity_pass_phrase("ssh-dss") ->
@@ -261,9 +262,9 @@ host_name(Atom) when is_atom(Atom) ->
 host_name(List) ->
     List.
 
-key_match(#'RSAPublicKey'{}, "ssh-rsa") ->
+key_match(#'RSAPublicKey'{}, 'ssh-rsa') ->
     true;
-key_match({_, #'Dss-Parms'{}}, "ssh-dss") ->
+key_match({_, #'Dss-Parms'{}}, 'ssh-dss') ->
     true;
 key_match(_, _) ->
     false.
@@ -272,11 +273,11 @@ add_key_fd(Fd, Host,Key) ->
     SshBin = public_key:ssh_encode([{Key, [{hostnames, [Host]}]}], known_hosts),
     file:write(Fd, SshBin).
 
-lookup_user_key_f(_, _User, [], _Alg, _F, _Opts) ->
+lookup_user_key_f(_, _User, [], _F, _Opts) ->
     {error, nouserdir};
-lookup_user_key_f(_, _User, nouserdir, _Alg, _F, _Opts) ->
+lookup_user_key_f(_, _User, nouserdir, _F, _Opts) ->
     {error, nouserdir};
-lookup_user_key_f(Key, _User, Dir, _Alg, F, _Opts) ->
+lookup_user_key_f(Key, _User, Dir, F, _Opts) ->
     FileName = filename:join(Dir, F),
     case file:open(FileName, [read, binary]) of
 	{ok, Fd} ->
diff --git a/lib/ssh/src/ssh_key_api.erl b/lib/ssh/src/ssh_key_api.erl
deleted file mode 100644
index 8085c12e21..0000000000
--- a/lib/ssh/src/ssh_key_api.erl
+++ /dev/null
@@ -1,45 +0,0 @@
-%%
-%% %CopyrightBegin%
-%%
-%% Copyright Ericsson AB 2011-2012. All Rights Reserved.
-%%
-%% The contents of this file are subject to the Erlang Public License,
-%% Version 1.1, (the "License"); you may not use this file except in
-%% compliance with the License. You should have received a copy of the
-%% Erlang Public License along with this software. If not, it can be
-%% retrieved online at http://www.erlang.org/.
-%%
-%% Software distributed under the License is distributed on an "AS IS"
-%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-%% the License for the specific language governing rights and limitations
-%% under the License.
-%%
-%% %CopyrightEnd%
-%%
-
--module(ssh_key_api).
-
--include_lib("public_key/include/public_key.hrl"). 
--include("ssh.hrl").
-
--type ssh_algorithm() :: string().
--type file_error()    :: file:posix() | badarg | system_limit | terminated.
-
--callback host_key(Algorithm :: ssh_algorithm(), Options :: list()) -> 
-                      {ok, [{public_key(), Attributes::list()}]} | public_key()
-                          | {error, string()}.
-
--callback user_key(Algorithm :: ssh_algorithm(), Options :: list()) -> 
-                     {ok, [{public_key(), Attributes::list()}]} | public_key()
-                          | {error, string()}.
-
--callback is_host_key(Key :: public_key(), PeerName :: string(), 
-                  Algorithm :: ssh_algorithm(), Options :: list()) ->
-                         boolean().
-
--callback add_host_key(Host :: string(), Key :: public_key(), Options :: list()) ->
-                          ok | {error, file_error()}.
-
--callback is_auth_key(Key :: public_key(), User :: string(),
-                  Algorithm :: ssh_algorithm(), Options :: list()) ->
-                         boolean().
diff --git a/lib/ssh/src/ssh_server_key.erl b/lib/ssh/src/ssh_server_key.erl
new file mode 100644
index 0000000000..8140114990
--- /dev/null
+++ b/lib/ssh/src/ssh_server_key.erl
@@ -0,0 +1,33 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2011-2012. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(ssh_server_key).
+
+-include_lib("public_key/include/public_key.hrl").
+-include("ssh.hrl").
+
+-type ssh_algorithm() :: string().
+
+-callback host_key(Algorithm :: ssh_algorithm(), Options :: list()) ->
+    {ok, [{public_key(), Attributes::list()}]} | public_key()
+	| {error, string()}.
+
+-callback is_auth_key(Key :: public_key(), User :: string(),
+		      Algorithm :: ssh_algorithm(), Options :: list()) ->
+    boolean().
diff --git a/lib/ssh/src/ssh_server_key_api.erl b/lib/ssh/src/ssh_server_key_api.erl
new file mode 100644
index 0000000000..4fd660ecb5
--- /dev/null
+++ b/lib/ssh/src/ssh_server_key_api.erl
@@ -0,0 +1,30 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2011-2012. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(ssh_server_key_api).
+
+-include_lib("public_key/include/public_key.hrl").
+-include("ssh.hrl").
+
+-callback host_key(Algorithm :: 'ssh-rsa'| 'ssh-dss'| atom(), DaemonOptions :: proplists:proplist()) ->
+    {ok, PrivateKey :: #'RSAPrivateKey'{}| #'DSAPrivateKey'{} |  term()} | {error, string()}.
+
+-callback is_auth_key(PublicKey :: #'RSAPublicKey'{}| {integer(),  #'Dss-Parms'{}}| term(),
+		      User :: string(), DaemonOptions :: proplists:proplist()) ->
+    boolean().
diff --git a/lib/ssh/src/ssh_sftpd.erl b/lib/ssh/src/ssh_sftpd.erl
index ec7b76b0b3..6d6f4a0121 100644
--- a/lib/ssh/src/ssh_sftpd.erl
+++ b/lib/ssh/src/ssh_sftpd.erl
@@ -24,7 +24,7 @@
 -module(ssh_sftpd).
 
 %%-behaviour(gen_server).
--behaviour(ssh_channel).
+-behaviour(ssh_subsystem).
 
 -include_lib("kernel/include/file.hrl").
 
@@ -36,7 +36,7 @@
 -export([subsystem_spec/1,
 	 listen/1, listen/2, listen/3, stop/1]).
 
--export([init/1, handle_ssh_msg/2, handle_msg/2, terminate/2, code_change/3]).
+-export([init/1, handle_ssh_msg/2, handle_msg/2, terminate/2]).
 
 -record(state, {
 	  xf,   			% [{channel,ssh_xfer states}...]
@@ -128,14 +128,6 @@ init(Options) ->
 
 
 %%--------------------------------------------------------------------
-%% Function: code_change(OldVsn, State, Extra) -> {ok, NewState}
-%% Description: 
-%%--------------------------------------------------------------------
-code_change(_OldVsn, State, _Extra) -> 
-    {ok, State}.
-
-
-%%--------------------------------------------------------------------
 %% Function: handle_ssh_msg(Args) -> {ok, State} | {stop, ChannelId, State}
 %%                        
 %% Description: Handles channel messages
diff --git a/lib/ssh/src/ssh_subsystem.erl b/lib/ssh/src/ssh_subsystem.erl
new file mode 100644
index 0000000000..5a9fa32668
--- /dev/null
+++ b/lib/ssh/src/ssh_subsystem.erl
@@ -0,0 +1,47 @@
+-module(ssh_subsystem).
+
+%% API to special server side channel that can be pluged into the erlang ssh daemeon
+-callback init(Args :: term()) ->
+    {ok, State :: term()} | {ok, State :: term(), timeout() | hibernate} |
+    {stop, Reason :: term()} | ignore.
+
+-callback terminate(Reason :: (normal | shutdown | {shutdown, term()} |
+                               term()),
+                    State :: term()) ->
+    term().
+
+-callback handle_msg(Msg ::term(), State :: term()) ->
+    {noreply, NewState :: term()} |
+    {noreply, NewState :: term(), timeout() | hibernate} |
+    {stop, Reason :: term(), NewState :: term()}.
+
+-callback handle_ssh_msg({ssh_cm, ConnectionRef::term(), SshMsg::term()},
+			 State::term()) -> {ok, State::term()} |
+					   {stop, ChannelId::integer(),
+					    State::term()}.
+
+%%% API
+-export([start/4, start/5, start_link/4, start_link/5, enter_loop/1]).
+
+%% gen_server callbacks
+-export([init/1, terminate/2]).
+
+start(ConnectionManager, ChannelId, CallBack, CbInitArgs) ->
+    ssh_channel:start(ConnectionManager, ChannelId, CallBack, CbInitArgs, undefined).
+
+start(ConnectionManager, ChannelId, CallBack, CbInitArgs, Exec) ->
+    ssh_channel:start(ConnectionManager, ChannelId, CallBack, CbInitArgs, Exec).
+
+start_link(ConnectionManager, ChannelId, CallBack, CbInitArgs) ->
+    ssh_channel:start_link(ConnectionManager, ChannelId, CallBack, CbInitArgs, undefined).
+
+start_link(ConnectionManager, ChannelId, CallBack, CbInitArgs, Exec) ->
+    ssh_channel:start_link(ConnectionManager, ChannelId, CallBack, CbInitArgs, Exec).
+
+enter_loop(State) ->
+    ssh_channel:enter_loop(State).
+
+init(Args) ->
+    ssh_channel:init(Args).
+terminate(Reason, State) ->
+    ssh_channel:terminate(Reason, State).
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index 7f6e7d9946..1abb69921d 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -449,7 +449,7 @@ verify_host_key_rsa(SSH, K_S, H, H_SIG) ->
 		false ->
 		    {error, bad_signature};
 		true ->
-		    known_host_key(SSH, Public, "ssh-rsa")
+		    known_host_key(SSH, Public, 'ssh-rsa')
 	    end;
 	_ ->
 	    {error, bad_format}
@@ -464,7 +464,7 @@ verify_host_key_dss(SSH, K_S, H, H_SIG) ->
 		false ->
 		    {error, bad_signature};
 		true ->
-		    known_host_key(SSH, Public, "ssh-dss")
+		    known_host_key(SSH, Public, 'ssh-dss')
 	    end;
 	_ ->
 	    {error, bad_host_key_format}