%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2010. 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(snmpa_trap).

%%%-----------------------------------------------------------------
%%% This module takes care of all trap(notification handling.
%%%-----------------------------------------------------------------
%% External exports
-export([construct_trap/2, 
	 try_initialise_vars/2, 
	 send_trap/6, send_trap/7]).
-export([send_discovery/5]).

%% Internal exports
-export([init_v2_inform/9, 
	 init_v3_inform/9, init_v3_inform/10, 
	 send_inform/6]).
-export([init_discovery_inform/12, send_discovery_inform/5]).

-include("snmp_types.hrl").
-include("snmpa_internal.hrl").
-include("SNMPv2-MIB.hrl").
-include("SNMPv2-TM.hrl").
-include("SNMPv2-TC.hrl").
-include("SNMP-FRAMEWORK-MIB.hrl").
-include("SNMP-TARGET-MIB.hrl").
-define(enterpriseSpecific, 6).


-define(VMODULE,"TRAP").
-include("snmp_verbosity.hrl").


%%-----------------------------------------------------------------
%% Trap mechanism
%% ==============
%% Distributed subagent (dSA) case
%%   The MIB with the TRAP-TYPE macro is loaded in dSA.  This means
%%   that dSA has info on all variables defined in the TRAP-TYPE,
%%   even though some variables may be located in other SA:s (or
%%   in the MA). Other variables that may be sent in the trap, 
%%   must be known by either the dSA, or some of its parent agents
%%   (e.g. the master agent), if the variable should be referred
%%   to by symbolic name. It is however possible to send other
%%   variables as well, but then the entire OID must be provided.
%%   The dSA locates the asn1 type, oid and value for as many
%%   variables as possible. This information, together with the
%%   variables for which the type, value or oid isn't known, is
%%   sent to the dSA's parent. This agent performs the same
%%   operation, and so on, until eventually the MA will receive the
%%   info. The MA then fills in the gaps, and at this point all
%%   oids and types must be known, otherwise an error is signalled,
%%   and the opertaion is aborted. For the unknown values for some 
%%   oids, a get-operation is performed by the MA. This will
%%   retreive the missing values.
%%   At this point, all oid, types and values are known, so the MA
%%   can distribute the traps according to the information in the
%%   internal tables.
%% 
%% Local subagent (lSA) case
%%   This case is similar to the case above.
%%
%% Master agent (MA) case
%%   This case is similar to the case above.
%%
%% NOTE: All trap forwarding between agents is made asynchronously.
%%
%% dSA: Distributed SA  (the #trap is loaded here)
%% nSA: [many] SAs between dSA and MA
%% MA:  Master Agent. (all trap info (destiniations is here))
%% 1) application decides to send a trap.
%% 2) dSA calls send_trap which initialises vars
%% 3) dSA sends all to nSA
%% 4) nSA tries to map symbolic names to oids and find the types
%%    of all variableoids with a value (and no type).
%% 5) nSA sends all to (n-1)SA
%% 6) MA tries to initialise vars
%% 7) MA makes a trappdu, and sends it to all destination.
%%
%% Problems with this implementation
%% =================================
%% It's ok to send {Oid, Value} but not just Oid. (it should be for
%%   any Oid)
%% It's ok to send {Name, Value} but not just Name. (it should be
%%   for Names in the hierarchy)
%% This approach might be too flexible; will people use it?
%% *NOTE*
%% Therefore, in this version we *do not* allow extra variables
%% in traps.
%% *YES* In _this_ version we do.
%%-----------------------------------------------------------------

%%-----------------------------------------------------------------
%% Func: construct_trap/2
%% Args: Trap is an atom
%%       Varbinds is a list of 
%%               {Variable, Value} | {SymbolicTableCol, RowIndex, Value} 
%%         where Variable is an atom or an OID, 
%%         where RowIndex is the indexes for the row.
%%         We don't check the RowIndex.
%% Purpose: This is the initially-called function. It is called
%%          by the agent that found out that a trap should be
%%          sent.
%%          Initialize as many variables as possible.
%% Returns: {ok, TrapRecord, <list of Var>} | error
%%          where Var is returned from initiate_vars.
%% NOTE: Executed at the inital SA
%%-----------------------------------------------------------------
construct_trap(Trap, Varbinds) ->
    ?vdebug("construct_trap -> entry with"
	"~n   Trap: ~p", [Trap]),
    case snmpa_symbolic_store:get_notification(Trap) of
	undefined -> 
	    user_err("construct_trap got undef Trap: ~w" , [Trap]),
	    error;

	{value, #trap{oidobjects = ListOfVars} = TRec} ->
	    ?vdebug("construct_trap -> trap"
		    "~n   ~p", [TRec]),
	    OidVbs        = [alias_to_oid(Vb) || Vb <- Varbinds],
	    LV            = initiate_vars(ListOfVars, OidVbs),
	    InitiatedVars = try_initialise_vars(get(mibserver), LV),
	    {ok, TRec, InitiatedVars};

	{value, #notification{oidobjects = ListOfVars} = NRec} ->
	    ?vdebug("construct_trap -> notification"
		    "~n   ~p", [NRec]),
	    OidVbs        = [alias_to_oid(Vb) || Vb <- Varbinds],
	    LV            = initiate_vars(ListOfVars, OidVbs),
	    InitiatedVars = try_initialise_vars(get(mibserver), LV), 
	    {ok, NRec, InitiatedVars}
    end.

alias_to_oid({Alias, Val}) when is_atom(Alias) ->
    case snmpa_symbolic_store:aliasname_to_oid(Alias) of
	{value, Oid} -> {lists:append(Oid, [0]), {value, Val}};
	_ ->   	     {Alias, {value, Val}}
    end;
alias_to_oid({Alias, RowIndex, Val}) when is_atom(Alias) ->
    case snmpa_symbolic_store:aliasname_to_oid(Alias) of
	{value, Oid} -> {lists:append(Oid, RowIndex), {value, Val}};
	_ ->   	     {Alias, RowIndex, {value, Val}}
    end;
alias_to_oid({Oid, Val}) -> {Oid, {value, Val}}.


%%-----------------------------------------------------------------
%% Func: initiate_vars/2
%% Args: ListOfVars is a list of {Oid, #asn1_type}
%%       Varbinds is a list of 
%%          {VariableOid, Value} | 
%%          {VariableAtom, Value} |
%%          {TableColAtom, RowIndex, Value}
%% Purpose: For each variable specified in the TRAP-TYPE macro
%%          (each in ListOfVars), check if it's got a value given
%%          in the Varbinds list.
%%          For each Oid:
%%            1) It has corresponding VariableOid. Use Value.
%%            2) No corresponding VariableOid. No value.
%% Returns: A list of
%%            {VariableOid, #asn1_type, Value} |
%%            {VariableOid, #asn1_type} |
%%            {VariableOid, Value} |
%%            {VariableAtom, Value} |
%%            {TableColAtom, RowIndex, Value}
%% NOTE: Executed at the inital SA
%%-----------------------------------------------------------------
initiate_vars([{Oid, Asn1Type} | T], Varbinds) ->
    case delete_oid_from_varbinds(Oid, Varbinds) of
	{undefined, _, _} ->
	    [{Oid, Asn1Type} | initiate_vars(T, Varbinds)];
	{Value, VarOid, RestOfVarbinds} ->
	    [{VarOid, Asn1Type, Value} | initiate_vars(T, RestOfVarbinds)]
    end;
initiate_vars([], Varbinds) ->
    Varbinds.
    
delete_oid_from_varbinds(Oid, [{VarOid, Value} | T]) ->
    case lists:prefix(Oid, VarOid) of
	true -> 
	    {Value, VarOid, T};
	_ -> 
	    {Value2, VarOid2, T2} = delete_oid_from_varbinds(Oid, T),
	    {Value2, VarOid2, [{VarOid, Value} | T2]}
    end;
delete_oid_from_varbinds(Oid, [H | T]) ->
    {Value, VarOid, T2} = delete_oid_from_varbinds(Oid, T),
    {Value, VarOid, [H | T2]};
delete_oid_from_varbinds(_Oid, []) -> {undefined, undefined, []}.

%%-----------------------------------------------------------------
%% Func: try_initialise_vars(Mib, Varbinds)
%% Args: Mib is the local mib process
%%       Varbinds is a list returned from initiate_vars.
%% Purpose: Try to initialise uninitialised vars.
%% Returns: see initiate_vars
%% NOTE: Executed at the intermediate SAs
%%-----------------------------------------------------------------
try_initialise_vars(Mib, Varbinds) ->
    V = try_map_symbolic(Varbinds),
    try_find_type(V, Mib).

%%-----------------------------------------------------------------
%% Func: try_map_symbolic/1
%% Args: Varbinds is a list returned from initiate_vars.
%% Purpose: Try to map symbolic name to oid for the 
%%          symbolic names left in the Varbinds list.
%% Returns: see initiate_vars.
%% NOTE: Executed at the intermediate SAs
%%-----------------------------------------------------------------
try_map_symbolic([Varbind | Varbinds]) ->
    [localise_oid(Varbind) | try_map_symbolic(Varbinds)];
try_map_symbolic([]) -> [].

localise_oid({VariableName, Value}) when is_atom(VariableName) ->
    alias_to_oid({VariableName, Value});
localise_oid({VariableName, RowIndex, Value}) when is_atom(VariableName) ->
    alias_to_oid({VariableName, RowIndex, Value});
localise_oid(X) -> X.

%%-----------------------------------------------------------------
%% Func: try_find_type/2
%% Args: Varbinds is a list returned from initiate_vars.
%%       Mib is a ref to the Mib process corresponding to
%%         this agent.
%% Purpose: Try to find the type for each variableoid with a value
%%          but no type.
%% Returns: see initiate_vars.
%% NOTE: Executed at the intermediate SAs
%%-----------------------------------------------------------------
try_find_type([Varbind | Varbinds], Mib) ->
    [localise_type(Varbind, Mib) | try_find_type(Varbinds, Mib)];
try_find_type([], _) -> [].

localise_type({VariableOid, Type}, _Mib) 
  when is_list(VariableOid) andalso is_record(Type, asn1_type) ->
    {VariableOid, Type};
localise_type({VariableOid, Value}, Mib) when is_list(VariableOid) ->
    case snmpa_mib:lookup(Mib, VariableOid) of
	{variable, ME} ->
	    {VariableOid, ME#me.asn1_type, Value};
	{table_column, ME, _} ->
	    {VariableOid, ME#me.asn1_type, Value};
	_ ->
	    {VariableOid, Value}
    end;
localise_type(X, _) -> X.

%%-----------------------------------------------------------------
%% Func: make_v1_trap_pdu/4
%% Args: Enterprise = oid()
%%       Specific = integer()
%%       Varbinds is as returned from initiate_vars
%%         (but only {Oid, Type[, Value} permitted)
%%       SysUpTime = integer()
%% Purpose: Make a #trappdu
%%          Checks the Varbinds to see that no symbolic names are
%%          present, and that each var has a type. Performs a get
%%          to find any missing value.
%% Returns: {#trappdu, [byte()] | error
%% Fails: yes
%% NOTE: Executed at the MA
%%-----------------------------------------------------------------
make_v1_trap_pdu(Enterprise, Specific, VarbindList, SysUpTime) ->
    {Enterp,Generic,Spec} = 
	case Enterprise of
	    ?snmp ->
		{sys_object_id(),Specific,0};
	    _ ->
		{Enterprise,?enterpriseSpecific,Specific}
    end,
    {value, AgentIp} = snmp_framework_mib:intAgentIpAddress(get),
    #trappdu{enterprise    = Enterp,
	     agent_addr    = AgentIp,
	     generic_trap  = Generic,
	     specific_trap = Spec,
	     time_stamp    = SysUpTime,
	     varbinds      = VarbindList}.

make_discovery_pdu(Vbs) ->
    #pdu{type         = 'inform-request',
	 request_id   = snmpa_mpd:generate_req_id(),
	 error_status = noError,
	 error_index  = 0,
	 varbinds     = Vbs}.

make_v2_notif_pdu(Vbs, Type) ->
    #pdu{type         = Type,
	 request_id   = snmpa_mpd:generate_req_id(),
	 error_status = noError,
	 error_index  = 0,
	 varbinds     = Vbs}.

make_varbind_list(Varbinds) ->
    {VariablesWithValueAndType, VariablesWithType} =
	split_variables( order(Varbinds) ),
    V    = get_values(VariablesWithType),
    Vars = lists:append([V, VariablesWithValueAndType]),
    [make_varbind(Var) || Var <- unorder(lists:keysort(1, Vars))].


%%-----------------------------------------------------------------
%% Func: send_trap/6
%% Args: TrapRec = #trap | #notification
%%       NotifyName = string()
%%       ContextName = string()
%%       Recv = no_receiver | {Ref, Receiver}
%%       Receiver = pid() | atom() | {M,F,A}
%%       Vbs = [varbind()]
%%       NetIf = pid()
%% Purpose: Default trap sending function.
%%          Sends the trap to the targets pointed out by NotifyName.
%%          If NotifyName is ""; the normal procedure defined in 
%%          SNMP-NOTIFICATION-MIB is used, i.e. the trap is sent to
%%          all managers.
%%          Otherwise, the NotifyName is used to find an entry in the
%%          SnmpNotifyTable which define how to send the notification
%%          (as an Inform or a Trap), and to select targets from
%%          SnmpTargetAddrTable (using the Tag).
%%-----------------------------------------------------------------
send_trap(TrapRec, NotifyName, ContextName, Recv, Vbs, NetIf) ->
    LocalEngineID = ?DEFAULT_LOCAL_ENGINE_ID, 
    send_trap(TrapRec, NotifyName, ContextName, Recv, Vbs, 
	      LocalEngineID, NetIf).

send_trap(TrapRec, NotifyName, ContextName, Recv, Vbs, LocalEngineID, NetIf) ->
    (catch do_send_trap(TrapRec, NotifyName, ContextName, Recv, Vbs, 
			LocalEngineID, NetIf)).

do_send_trap(TrapRec, NotifyName, ContextName, Recv, Vbs, 
	     LocalEngineID, NetIf) ->
    VarbindList = make_varbind_list(Vbs),
    Dests       = find_dests(NotifyName),
    send_trap_pdus(Dests, ContextName, {TrapRec, VarbindList}, [], [], [],
		   Recv, LocalEngineID, NetIf).

send_discovery(TargetName, Record, ContextName, Vbs, NetIf) ->
    case find_dest(TargetName) of
	{ok, Dest} ->
	    send_discovery_pdu(Dest, Record, ContextName, Vbs, NetIf);
	Error ->
	    Error
    end.


get_values(VariablesWithType) ->
    {Order, Varbinds} = extract_order(VariablesWithType, 1),
    case snmpa_agent:do_get(snmpa_acm:get_root_mib_view(), Varbinds, true) of
	{noError, _, NewVarbinds} ->
	    %% NewVarbinds is the result of:
	    %% first a reverse, then a sort on the oid field and finally 
	    %% a reverse during the get-processing so we need to re-sort 
	    %% on the org_index field again before contract-order
 	    NewVarbinds1 = lists:keysort(#varbind.org_index, NewVarbinds),
 	    contract_order(Order, NewVarbinds1);
	{ErrorStatus, ErrorIndex, _} ->
	    user_err("snmpa_trap: get operation failed: ~w"
		     "~n    at ~w"
		     "~n    in ~w",
		     [ErrorStatus, ErrorIndex, Varbinds]),
	    throw(error)
    end.
    
make_varbind(Varbind) when is_record(Varbind, varbind) ->
    Varbind;
make_varbind({VarOid, ASN1Type, Value}) ->
    case snmpa_agent:make_value_a_correct_value(Value, ASN1Type, undef) of
	{value, Type, Val} ->
	    #varbind{oid = VarOid, variabletype = Type, value = Val};
	{error, Reason} -> 
	    user_err("snmpa_trap: Invalid value: ~w"
		     "~n   Oid:  ~w"
		     "~n   Val:  ~w"
		     "~n   Type: ~w",
		     [Reason, VarOid, Value, ASN1Type]),
	    throw(error)
    end.

order(Varbinds) -> 
    order(Varbinds, 1).

order([H | T], No) -> [{No, H} | order(T, No + 1)];
order([], _) -> [].

unorder([{_No, H} | T]) -> [H | unorder(T)];
unorder([]) -> [].

extract_order([{No, {VarOid, _Type}} | T], Index) ->
    {Order, V} = extract_order(T, Index+1),
    {[No | Order], [#varbind{oid = VarOid, org_index = Index} | V]};
extract_order([], _) -> {[], []}.

contract_order([No | Order], [Varbind | T]) ->
    [{No, Varbind} | contract_order(Order, T)];
contract_order([], []) -> 
    [].

split_variables([{No, {VarOid, Type, Val}} | T]) when is_list(VarOid) ->
    {A, B} = split_variables(T),
    {[{No, {VarOid, Type, Val}} | A], B};
split_variables([{No, {VarOid, Type}} | T]) 
  when is_list(VarOid) andalso is_record(Type, asn1_type) ->
    {A, B} = split_variables(T),
    {A, [{No, {VarOid, Type}} | B]};
split_variables([{_No, {VarName, Value}} | _T]) ->
    user_err("snmpa_trap: Undefined variable ~w (~w)", [VarName, Value]),
    throw(error);
split_variables([{_No, {VarName, RowIndex, Value}} | _T]) ->
    user_err("snmpa_trap: Undefined variable ~w ~w (~w)",
	     [VarName, RowIndex, Value]),
    throw(error);
split_variables([]) -> {[], []}.


%%-----------------------------------------------------------------
%% Func: find_dests(NotifyName) -> 
%%          [{DestAddr, TargetName, TargetParams, NotifyType}]
%% Types: NotifyType = string()
%%        DestAddr = {TDomain, TAddr}
%%        TargetName = string()
%%        TargetParams = {MpModel, SecModel, SecName, SecLevel}
%%        NotifyType = trap | {inform, Timeout, Retry}
%% Returns: A list of all Destination addresses for this community.
%% NOTE: This function is executed in the master agent's context
%%-----------------------------------------------------------------
find_dests("") ->
    snmp_notification_mib:get_targets();
find_dests(NotifyName) ->
    case snmp_notification_mib:get_targets(NotifyName) of
	[] ->
	    ?vlog("No dests found for snmpNotifyName: ~p",[NotifyName]),
	    [];
	Dests ->
	    Dests
    end.

find_dest(TargetName) ->
    AddrCols = [?snmpTargetAddrTDomain,
		?snmpTargetAddrTAddress,
		?snmpTargetAddrTimeout,
		?snmpTargetAddrRetryCount,
		?snmpTargetAddrParams,
		?snmpTargetAddrRowStatus],
    case snmp_target_mib:snmpTargetAddrTable(get, TargetName, AddrCols) of
	[{value, TDomain},
	 {value, TAddress},
	 {value, Timeout},
	 {value, RetryCount},
	 {value, Params},
	 {value, ?'RowStatus_active'}] ->
	    ?vtrace("find_dest -> found snmpTargetAddrTable info:"
		    "~n   TDomain:    ~p"
		    "~n   TAddress:   ~p"
		    "~n   Timeout:    ~p"
		    "~n   RetryCount: ~p"
		    "~n   Params:     ~p", 
		    [TDomain, TAddress, Timeout, RetryCount, Params]),
	    ParmCols = [?snmpTargetParamsMPModel,
			?snmpTargetParamsSecurityModel,
			?snmpTargetParamsSecurityName,
			?snmpTargetParamsSecurityLevel,
			?snmpTargetParamsRowStatus],
	    case snmp_target_mib:snmpTargetParamsTable(get, Params, ParmCols) of
		[{value, ?MP_V3}, 
		 {value, SecModel}, 
		 {value, SecName}, 
		 {value, SecLevel},
		 {value, ?'RowStatus_active'}] ->
		    ?vtrace("find_dest -> found snmpTargetParamsTable info:"
			    "~n   SecModel: ~p"
			    "~n   SecName:  ~p"
			    "~n   SecLevel: ~p", 
			    [SecModel, SecName, SecLevel]),
		    DestAddr     = {TDomain, TAddress},
		    TargetParams = {SecModel, SecName, SecLevel},
		    Val = {DestAddr, TargetName, TargetParams, Timeout, RetryCount},
		    {ok, Val};
		[{value, ?MP_V3}, 
		 {value, _SecModel}, 
		 {value, _SecName}, 
		 {value, _SecLevel},
		 {value, RowStatus}] ->
		    {error, {invalid_RowStatus, RowStatus, snmpTargetParamsTable}};
		[{value, MpModel}, 
		 {value, _SecModel}, 
		 {value, _SecName}, 
		 {value, _SecLevel},
		 {value, ?'RowStatus_active'}] ->
		    {error, {invalid_MpModel, MpModel, snmpTargetParamsTable}};
		[{value, _MpModel}, 
		 {value, _SecModel}, 
		 {value, _SecName}, 
		 {value, _SecLevel},
		 {value, RowStatus}] ->
		    {error, {invalid_RowStatus, RowStatus, snmpTargetParamsTable}};
		Bad ->
		    ?vlog("find_dest -> "
			  "could not find snmpTargetParamsTable info: "
			  "~n   Bad: ~p", [Bad]),
		    {error, {not_found, snmpTargetParamsTable}}
	    end;
	
	[{value, _TDomain},
	 {value, _TAddress},
	 {value, _Timeout},
	 {value, _RetryCount},
	 {value, _Params},
	 {value, RowStatus}] ->
	    {error, {invalid_RowStatus, RowStatus, snmpTargetAddrTable}};
	_ ->
	    {error, {not_found, snmpTargetAddrTable}}
    end.

send_discovery_pdu({Dest, TargetName, {SecModel, SecName, SecLevel}, 
		    Timeout, Retry}, 
		   Record, ContextName, Vbs, NetIf) ->
    ?vdebug("send_discovery_pdu -> entry with "
	    "~n   Destination address: ~p"
	    "~n   Target name:         ~p"
	    "~n   Sec model:           ~p"
	    "~n   Sec name:            ~p"
	    "~n   Sec level:           ~p"
	    "~n   Timeout:             ~p"
	    "~n   Retry:               ~p"
	    "~n   Record:              ~p"
	    "~n   ContextName:         ~p",
	    [Dest, TargetName, SecModel, SecName, SecLevel, 
	     Timeout, Retry, Record, ContextName]),
    case get_mib_view(SecModel, SecName, SecLevel, ContextName) of
	{ok, MibView} ->
	    case check_all_varbinds(Record, Vbs, MibView) of
		true ->
		    SysUpTime = snmp_standard_mib:sys_up_time(), 
		    send_discovery_pdu(Record, Dest, Vbs, 
				       SecModel, SecName, SecLevel, 
				       TargetName, ContextName, 
				       Timeout, Retry, 
				       SysUpTime, NetIf);
		false ->
		    {error, {mibview_validation_failed, Vbs, MibView}}
	    end;
	{discarded, Reason} ->
	    {error, {failed_get_mibview, Reason}}
    end.

send_discovery_pdu(Record, Dest, Vbs, 
		   SecModel, SecName, SecLevel, TargetName, 
		   ContextName, Timeout, Retry, SysUpTime, NetIf) ->
    {_Oid, IVbs} = mk_v2_trap(Record, Vbs, SysUpTime), % v2 refers to SMIv2;
    Sender = proc_lib:spawn_link(?MODULE, init_discovery_inform,
				 [self(), 
				  Dest, 
				  SecModel, SecName, SecLevel, TargetName,
				  ContextName, 
				  Timeout, Retry, 
				  IVbs, NetIf, 
				  get(verbosity)]),
    {ok, Sender, SecLevel}.

init_discovery_inform(Parent, 
		      Dest, 
		      SecModel, SecName, SecLevel, TargetName, 
		      ContextName, Timeout, Retry, Vbs, NetIf, Verbosity) ->
    put(verbosity, Verbosity),
    put(sname, madis),
    Pdu = make_discovery_pdu(Vbs), 
    ContextEngineId = snmp_framework_mib:get_engine_id(),
    SecLevelFlag = mk_flag(SecLevel), 
    SecData      = {SecModel, SecName, SecLevelFlag, TargetName}, 
    MsgData      = {SecData, ContextEngineId, ContextName}, 
    Msg          = {send_discovery, Pdu, MsgData, Dest, self()},
    ?MODULE:send_discovery_inform(Parent, Timeout*10, Retry, Msg, NetIf).

%% note_timeout(Timeout, Retry) 
%%   when ((is_integer(Timeout) andalso (Timeout > 0)) andalso 
%% 	(is_integer(Retry) andalso (Retry > 0)))
%%     note_timeout(Timeout*10, Retry, 0);
%% note_timeout(Timeout, Retry) 
%%   when (is_integer(Timeout) andalso (Timeout > 0)) ->
%%     Timeout*10.

%% note_timeout(_Timeout, -1, NoteTimeout) ->
%%     NoteTimeout;
%% note_timeout(Timeout, Retry, NoteTimeout) when ->
%%     note_timeout(Timeout*2, Retry-1, NoteTimeout+Timeout).

send_discovery_inform(Parent, _Timeout, -1, _Msg, _NetIf) ->
    Parent ! {discovery_response, {error, timeout}};
send_discovery_inform(Parent, Timeout, Retry, Msg, NetIf) ->
    NetIf ! Msg,
    receive
	{snmp_discovery_response_received, Pdu, undefined} ->
	    ?vtrace("received stage 2 discovery response: "
		    "~n   Pdu: ~p", [Pdu]),
	    Parent ! {discovery_response, {ok, Pdu}};
	{snmp_discovery_response_received, Pdu, ManagerEngineId} ->
	    ?vtrace("received stage 1 discovery response: "
		    "~n   Pdu:             ~p"
		    "~n   ManagerEngineId: ~p", [Pdu, ManagerEngineId]),
	    Parent ! {discovery_response, {ok, Pdu, ManagerEngineId}}
    after
	Timeout ->
	    ?MODULE:send_discovery_inform(Parent, 
					  Timeout*2, Retry-1, Msg, NetIf)
    end.

    
%%-----------------------------------------------------------------
%% NOTE: This function is executed in the master agent's context
%% For each target, check if it has access to the objects in the
%% notification, determine which message version (v1, v2c or v3)
%% should be used for the target, and determine the message
%% specific parameters to be used.
%%-----------------------------------------------------------------
send_trap_pdus([{DestAddr, TargetName, {MpModel, SecModel, SecName, SecLevel},
		 Type} | T],
	       ContextName, 
	       {TrapRec, Vbs}, V1Res, V2Res, V3Res, Recv, 
	       LocalEngineID, NetIf) ->
    ?vdebug("send trap pdus: "
	    "~n   Destination address: ~p"
	    "~n   Target name:         ~p"
	    "~n   MP model:            ~p"
	    "~n   Type:                ~p"
	    "~n   V1Res:               ~p"
	    "~n   V2Res:               ~p"
	    "~n   V3Res:               ~p",
	    [DestAddr, TargetName, MpModel, Type, V1Res, V2Res, V3Res]),
    case get_mib_view(SecModel, SecName, SecLevel, ContextName) of
	{ok, MibView} ->
	    case check_all_varbinds(TrapRec, Vbs, MibView) of
		true when MpModel =:= ?MP_V1 ->
		    ?vtrace("send_trap_pdus -> v1 mp model",[]),
		    ContextEngineId = LocalEngineID, 
		    case snmp_community_mib:vacm2community({SecName,
							    ContextEngineId,
							    ContextName},
							   DestAddr) of
			{ok, Community} ->
			    ?vdebug("community found  for v1 dest: ~p",
				    [element(2, DestAddr)]),
			    send_trap_pdus(T, ContextName, {TrapRec, Vbs},
					   [{DestAddr, Community} | V1Res],
					   V2Res, V3Res, Recv, 
					   LocalEngineID, NetIf);
			undefined ->
			    ?vdebug("No community found for v1 dest: ~p", 
				    [element(2, DestAddr)]),
			    send_trap_pdus(T, ContextName, {TrapRec, Vbs},
					   V1Res, V2Res, V3Res, Recv, 
					   LocalEngineID, NetIf)
		    end;
		true when MpModel =:= ?MP_V2C ->
		    ?vtrace("send_trap_pdus -> v2c mp model",[]),
		    ContextEngineId = LocalEngineID, 
		    case snmp_community_mib:vacm2community({SecName,
							    ContextEngineId,
							    ContextName},
							   DestAddr) of
			{ok, Community} ->
			    ?vdebug("community found for v2c dest: ~p", 
				    [element(2, DestAddr)]),
			    send_trap_pdus(T, ContextName, {TrapRec, Vbs},
					   V1Res,
					   [{DestAddr, Community, Type}|V2Res],
					   V3Res, Recv, LocalEngineID, NetIf);
			undefined ->
			    ?vdebug("No community found for v2c dest: ~p", 
				    [element(2, DestAddr)]),
			    send_trap_pdus(T, ContextName, {TrapRec, Vbs},
					   V1Res, V2Res, V3Res, Recv, 
					   LocalEngineID, NetIf)
		    end;
		true when MpModel =:= ?MP_V3 ->
		    ?vtrace("send_trap_pdus -> v3 mp model",[]),
		    SecLevelF = mk_flag(SecLevel),
		    MsgData = {SecModel, SecName, SecLevelF, TargetName},
		    send_trap_pdus(T, ContextName, {TrapRec, Vbs},
				   V1Res, V2Res,
				   [{DestAddr, MsgData, Type} | V3Res],
				   Recv, LocalEngineID, NetIf);
		true ->
		    ?vlog("bad MpModel ~p for dest ~p",
			  [MpModel, element(2, DestAddr)]),
		    send_trap_pdus(T, ContextName, {TrapRec, Vbs},
				   V1Res, V2Res, V3Res, Recv, 
				   LocalEngineID, NetIf);
		_ ->
		    ?vlog("no access for dest: "
			  "~n   ~p in target ~p",
			  [element(2, DestAddr), TargetName]),
		    send_trap_pdus(T, ContextName, {TrapRec, Vbs},
				   V1Res, V2Res, V3Res, Recv, 
				   LocalEngineID, NetIf)
	    end;
	{discarded, Reason} ->
	    ?vlog("mib view error ~p for"
		  "~n   dest:    ~p"
		  "~n   SecName: ~w", 
		  [Reason, element(2, DestAddr), SecName]),
	    send_trap_pdus(T, ContextName, {TrapRec, Vbs},
			   V1Res, V2Res, V3Res, Recv, LocalEngineID, NetIf)
    end;
send_trap_pdus([], ContextName, {TrapRec, Vbs}, V1Res, V2Res, V3Res,
	       Recv, LocalEngineID, NetIf) ->
    SysUpTime = snmp_standard_mib:sys_up_time(),
    ?vdebug("send trap pdus with sysUpTime ~p", [SysUpTime]),
    InformRecvs   = get_inform_recvs(V2Res ++ V3Res),
    InformTargets = [Addr || {Addr, _, _, _} <- InformRecvs],
    deliver_recv(Recv, snmp_targets, InformTargets),
    send_v1_trap(TrapRec, V1Res, Vbs, NetIf, SysUpTime),
    send_v2_trap(TrapRec, V2Res, Vbs, Recv, NetIf, SysUpTime),
    send_v3_trap(TrapRec, V3Res, Vbs, Recv, LocalEngineID, NetIf, 
		 SysUpTime, ContextName).

send_v1_trap(_TrapRec, [], _Vbs, _NetIf, _SysUpTime) ->
    ok;
send_v1_trap(#trap{enterpriseoid = Enter, specificcode = Spec},
	     V1Res, Vbs, NetIf, SysUpTime) ->
    ?vdebug("prepare to send v1 trap "
	    "~n   '~p'"
	    "~n   with"
	    "~n   ~p"
	    "~n   to"
	    "~n   ~p", [Enter, Spec, V1Res]),
    TrapPdu = make_v1_trap_pdu(Enter, Spec, Vbs, SysUpTime),
    AddrCommunities = mk_addr_communities(V1Res),
    lists:foreach(fun({Community, Addrs}) ->
			  ?vtrace("send v1 trap pdu to ~p",[Addrs]),
			  NetIf ! {send_pdu, 'version-1', TrapPdu,
				   {community, Community}, Addrs}
		  end, AddrCommunities);
send_v1_trap(#notification{oid = Oid}, V1Res, Vbs, NetIf, SysUpTime) ->
    %% Use alg. in rfc2089 to map a v2 trap to a v1 trap
    % delete Counter64 objects from vbs
    ?vdebug("prepare to send v1 trap '~p'",[Oid]),
    NVbs = [Vb || Vb <- Vbs, Vb#varbind.variabletype =/= 'Counter64'],
    {Enter,Spec} = 
	case Oid of
	    [1,3,6,1,6,3,1,1,5,Specific] ->
		{?snmp,Specific - 1};
	    _ ->
		case lists:reverse(Oid) of
		    [Last, 0 | First] ->
			{lists:reverse(First),Last};
		    [Last | First] ->
			{lists:reverse(First),Last}
		end
	end,
    TrapPdu = make_v1_trap_pdu(Enter, Spec, NVbs, SysUpTime),
    AddrCommunities = mk_addr_communities(V1Res),
    lists:foreach(fun({Community, Addrs}) ->
			  ?vtrace("send v1 trap to ~p",[Addrs]),
			  NetIf ! {send_pdu, 'version-1', TrapPdu,
				   {community, Community}, Addrs}
		  end, AddrCommunities).
    
send_v2_trap(_TrapRec, [], _Vbs, _Recv, _NetIf, _SysUpTime) ->
    ok;
send_v2_trap(TrapRec, V2Res, Vbs, Recv, NetIf, SysUpTime) ->
    ?vdebug("prepare to send v2 trap",[]),
    {_Oid, IVbs} = mk_v2_trap(TrapRec, Vbs, SysUpTime),
    TrapRecvs = get_trap_recvs(V2Res),
    InformRecvs = get_inform_recvs(V2Res),
    do_send_v2_trap(TrapRecvs, IVbs, NetIf),
    do_send_v2_inform(InformRecvs, IVbs, Recv, NetIf).
    
send_v3_trap(_TrapRec, [], _Vbs, _Recv, _LocalEngineID, 
	     _NetIf, _SysUpTime, _ContextName) ->
    ok;
send_v3_trap(TrapRec, V3Res, Vbs, Recv, LocalEngineID, 
	     NetIf, SysUpTime, ContextName) ->
    ?vdebug("prepare to send v3 trap",[]),
    {_Oid, IVbs} = mk_v2_trap(TrapRec, Vbs, SysUpTime), % v2 refers to SMIv2;
    TrapRecvs = get_trap_recvs(V3Res),                  % same SMI for v3
    InformRecvs = get_inform_recvs(V3Res),
    do_send_v3_trap(TrapRecvs, ContextName, IVbs, NetIf),
    do_send_v3_inform(InformRecvs, ContextName, IVbs, Recv, 
		      LocalEngineID, NetIf).
    

mk_v2_trap(#notification{oid = Oid}, Vbs, SysUpTime) ->
    ?vtrace("make v2 notification '~p'",[Oid]),
    mk_v2_notif(Oid, Vbs, SysUpTime);
mk_v2_trap(#trap{enterpriseoid = Enter, specificcode = Spec}, 
	   Vbs, SysUpTime) ->
    %% Use alg. in rfc1908 to map a v1 trap to a v2 trap
    ?vtrace("make v2 trap for '~p' with ~p",[Enter,Spec]),
    {Oid,Enterp} = 
	case Enter of
	    ?snmp ->
		{?snmpTraps ++ [Spec + 1],sys_object_id()};
	    _ ->
		{Enter ++ [0, Spec],Enter}
	end,
    ExtraVb = #varbind{oid = ?snmpTrapEnterprise_instance,
		       variabletype = 'OBJECT IDENTIFIER',
		       value = Enterp},
    mk_v2_notif(Oid, Vbs ++ [ExtraVb], SysUpTime).
    
mk_v2_notif(Oid, Vbs, SysUpTime) ->
    IVbs = [#varbind{oid = ?sysUpTime_instance,
		     variabletype = 'TimeTicks',
		     value = SysUpTime},
	    #varbind{oid = ?snmpTrapOID_instance,
		     variabletype = 'OBJECT IDENTIFIER',
		     value = Oid} | Vbs],
    {Oid, IVbs}.

get_trap_recvs(TrapRecvs) ->
    [{Addr, MsgData} || {Addr, MsgData, trap} <- TrapRecvs].

get_inform_recvs(InformRecvs) ->
    [{Addr, MsgData, Timeout, Retry} || 
	{Addr, MsgData, {inform, Timeout, Retry}} <- InformRecvs].

do_send_v2_trap([], _Vbs, _NetIf) ->
    ok;
do_send_v2_trap(Recvs, Vbs, NetIf) ->
    TrapPdu = make_v2_notif_pdu(Vbs, 'snmpv2-trap'),
    AddrCommunities = mk_addr_communities(Recvs),
    lists:foreach(fun({Community, Addrs}) ->
			  ?vtrace("~n   send v2 trap to ~p",[Addrs]),
			  NetIf ! {send_pdu, 'version-2', TrapPdu,
				   {community, Community}, Addrs}
		  end, AddrCommunities),
    ok.

do_send_v2_inform([], _Vbs, _Recv, _NetIf) ->
    ok;
do_send_v2_inform(Recvs, Vbs, Recv, NetIf) ->
    lists:foreach(
      fun({Addr, Community, Timeout, Retry}) ->
	      ?vtrace("~n   start inform sender to send v2 inform to ~p",
		      [Addr]),
	      proc_lib:spawn_link(?MODULE, init_v2_inform,
				  [Addr, Timeout, Retry, Vbs,
				   Recv, NetIf, Community,
				   get(verbosity), get(sname)])
      end, 
      Recvs).

do_send_v3_trap([], _ContextName, _Vbs, _NetIf) ->
    ok;
do_send_v3_trap(Recvs, ContextName, Vbs, NetIf) ->
    TrapPdu = make_v2_notif_pdu(Vbs, 'snmpv2-trap'), % Yes, v2
    ContextEngineId = snmp_framework_mib:get_engine_id(),
    lists:foreach(fun(Recv) ->
			  ?vtrace("~n   send v3 notif to ~p",[Recv]),
			  NetIf ! {send_pdu, 'version-3', TrapPdu,
				   {v3, ContextEngineId, ContextName}, [Recv]}
		  end, Recvs),
    ok.

do_send_v3_inform([], _ContextName, _Vbs, _Recv, _LocalEngineID, _NetIf) ->
    ok;
do_send_v3_inform(Recvs, ContextName, Vbs, Recv, LocalEngineID, NetIf) ->
    lists:foreach(
      fun({Addr, MsgData, Timeout, Retry}) ->
	      ?vtrace("~n   start inform sender to send v3 inform to ~p",
		      [Addr]),
	      proc_lib:spawn_link(?MODULE, init_v3_inform,
				  [{Addr, MsgData}, Timeout, Retry, Vbs,
				   Recv, LocalEngineID, NetIf, ContextName,
				   get(verbosity), get(sname)])
      end, 
      Recvs).

%% New process
init_v2_inform(Addr, Timeout, Retry, Vbs, Recv, NetIf, Community,V,S) ->
    %% Make a new Inform for each recipient; they need unique
    %% request-ids!
    put(verbosity,V),
    put(sname,inform_sender_short_name(S)),
    ?vdebug("~n   starting with timeout = ~p and retry = ~p",
	    [Timeout,Retry]),
    InformPdu = make_v2_notif_pdu(Vbs, 'inform-request'),
    Msg = {send_pdu_req, 'version-2', InformPdu, {community, Community},
	   [Addr], self()},
    ?MODULE:send_inform(Addr, Timeout*10, Retry, Msg, Recv, NetIf).
    

%% New process
init_v3_inform(Addr, Timeout, Retry, Vbs, Recv, NetIf, ContextName, V, S) ->
    LocalEngineID = ?DEFAULT_LOCAL_ENGINE_ID, 
    init_v3_inform(Addr, Timeout, Retry, Vbs, Recv, LocalEngineID, 
		   NetIf, ContextName, V, S).

init_v3_inform(Addr, Timeout, Retry, Vbs, Recv, LocalEngineID, 
	       NetIf, ContextName, V, S) ->
    %% Make a new Inform for each recipient; they need unique
    %% request-ids!
    put(verbosity,V),
    put(sname,inform_sender_short_name(S)),
    ?vdebug("~n   starting with timeout = ~p and retry = ~p",
	    [Timeout,Retry]),
    InformPdu = make_v2_notif_pdu(Vbs, 'inform-request'), % Yes, v2
    ContextEngineId = LocalEngineID, 
    Msg = {send_pdu_req, 'version-3', InformPdu,
	   {v3, ContextEngineId, ContextName}, [Addr], self()},
    ?MODULE:send_inform(Addr, Timeout*10, Retry, Msg, Recv, NetIf).

send_inform(Addr, _Timeout, -1, _Msg,  Recv, _NetIf) ->
    ?vinfo("~n   Delivery of send-pdu-request to net-if failed: reply timeout",
	   []),
    deliver_recv(Recv, snmp_notification, {no_response, Addr});
send_inform(Addr, Timeout, Retry, Msg, Recv, NetIf) ->
    ?vtrace("deliver send-pdu-request to net-if when"
	    "~n   Timeout: ~p"
	    "~n   Retry:   ~p",[Timeout, Retry]),
    NetIf ! Msg,
    receive
	{snmp_response_received, _Vsn, _Pdu, _From} ->
	    ?vtrace("received response for ~p (when Retry = ~p)", 
		    [Recv, Retry]),
	    deliver_recv(Recv, snmp_notification, {got_response, Addr})
    after
	Timeout ->
	    ?MODULE:send_inform(Addr, Timeout*2, Retry-1, Msg, Recv, NetIf)
    end.

% A nasty bit of verbosity setup...    
inform_sender_short_name(ma)   -> mais;
inform_sender_short_name(maw)  -> mais;
inform_sender_short_name(mats) -> mais;
inform_sender_short_name(_)    -> sais.

deliver_recv(no_receiver, _MsgId, _Result) ->
    ?vtrace("deliver_recv -> no receiver", []),
    ok;
deliver_recv(#snmpa_notification_delivery_info{tag   = Tag,
					       mod   = Mod,
					       extra = Extra},
	     snmp_targets, TAddrs) when is_list(TAddrs) ->
    ?vtrace("deliver_recv(snmp_targets) -> entry with"
	"~n   Tag:    ~p"
	"~n   Mod:    ~p"
	"~n   Extra:  ~p"
	"~n   TAddrs: ~p"
	"", [Tag, Mod, Extra, TAddrs]),
    Addrs = transform_taddrs(TAddrs),
    (catch Mod:delivery_targets(Tag, Addrs, Extra));
deliver_recv(#snmpa_notification_delivery_info{tag   = Tag,
					       mod   = Mod,
					       extra = Extra},
	     snmp_notification, {DeliveryResult, TAddr}) ->
    ?vtrace("deliver_recv -> entry with"
	"~n   Tag:            ~p"
	"~n   Mod:            ~p"
	"~n   Extra:          ~p"
	"~n   DeliveryResult: ~p"
	"~n   TAddr:          ~p"
	"", [Tag, Mod, Extra, DeliveryResult, TAddr]),
    Addr = transform_taddr(TAddr),
    (catch Mod:delivery_info(Tag, Addr, DeliveryResult, Extra));
deliver_recv({Tag, Receiver}, MsgId, Result) ->
    ?vtrace("deliver_recv -> entry with"
	"~n   Tag:      ~p"
	"~n   Receiver: ~p"
	"~n   MsgId:    ~p"
	"~n   Result:   ~p"
	"", [Tag, Receiver, MsgId, Result]),
    Msg = {MsgId, Tag, Result},
    case Receiver of
	Pid when is_pid(Pid) ->
	    Pid ! Msg;
	Name when is_atom(Name) ->
	    catch Name ! Msg;
	{M, F, A} ->
	    catch M:F([Msg | A]);
	Else ->
	    ?vinfo("~n   Cannot deliver acknowledgment: bad receiver = '~p'",
		   [Else]),
	    user_err("snmpa: bad receiver, ~w\n", [Else])
    end;
deliver_recv(Else, _MsgId, _Result) ->
    ?vinfo("~n   Cannot deliver acknowledgment: bad receiver = '~p'",
	   [Else]),
    user_err("snmpa: bad receiver, ~w\n", [Else]).

transform_taddrs(Addrs) ->
    [transform_taddr(Addr) || Addr <- Addrs].

transform_taddr({?snmpUDPDomain, [A1, A2, A3, A4, P1, P2]}) -> % v2
    Addr = {A1, A2, A3, A4},
    Port = P1 bsl 8 + P2,
    {Addr, Port};
transform_taddr({{?snmpUDPDomain, [A1, A2, A3, A4, P1, P2]}, _MsgData}) -> % v3
    Addr = {A1, A2, A3, A4},
    Port = P1 bsl 8 + P2,
    {Addr, Port}.


check_all_varbinds(#notification{oid = Oid}, Vbs, MibView) ->
    case snmpa_acm:validate_mib_view(Oid, MibView) of
	true  -> check_all_varbinds(Vbs, MibView);
	false -> false
    end;
check_all_varbinds(#trap{enterpriseoid = Enter, specificcode = Spec},
		   Vbs, MibView) ->
    %% Use alg. in rfc1908 to map a v1 trap to a v2 trap
    Oid = case Enter of
	      ?snmp -> ?snmpTraps ++ [Spec + 1];
	      _ -> Enter ++ [0, Spec]
	  end,
    case snmpa_acm:validate_mib_view(Oid, MibView) of
	true  -> check_all_varbinds(Vbs, MibView);
	false -> false
    end.

check_all_varbinds([#varbind{oid = Oid} | Vbs], MibView) ->
    case snmpa_acm:validate_mib_view(Oid, MibView) of
	true -> check_all_varbinds(Vbs, MibView);
	false -> false
    end;
check_all_varbinds([], _MibView) -> 
    true.


%%--------------------------------------------------
%% Functions to access the local mib.
%%--------------------------------------------------
sys_object_id() ->
    case snmpa_agent:do_get(snmpa_acm:get_root_mib_view(),
			    [#varbind{oid = ?sysObjectID_instance}],
			    true) of
	{noError, _, [#varbind{value = Value}]} ->
	    Value;
	X ->
	    user_err("sysObjectID bad return value ~w", [X])
    end.

%% Collect all ADDRs for each community together.
%% In: [{Addr, Community}]
%% Out: [{Community, [Addr]}]
mk_addr_communities(Recvs) ->
    [{Addr, Comm} | T] = lists:keysort(2, Recvs),
    mic(T, Comm, [Addr], []).

mic([{Addr, Comm} | T], CurComm, AddrList, Res) when Comm == CurComm ->
    mic(T, CurComm, [Addr | AddrList], Res);
mic([{Addr, Comm} | T], CurComm, AddrList, Res) ->
    mic(T, Comm, [Addr], [{CurComm, AddrList} | Res]);
mic([], CurComm, AddrList, Res) ->
    [{CurComm, AddrList} | Res].

%%-----------------------------------------------------------------
%% Convert the SecurityLevel into a flag value used by snmpa_mpd
%%-----------------------------------------------------------------
mk_flag(?'SnmpSecurityLevel_noAuthNoPriv') -> 0;
mk_flag(?'SnmpSecurityLevel_authNoPriv') -> 1;
mk_flag(?'SnmpSecurityLevel_authPriv') -> 3.
     

%%--------------------------------------------------
%% Mib view wrapper
%%--------------------------------------------------
get_mib_view(SecModel, SecName, SecLevel, ContextName) ->
    snmpa_vacm:get_mib_view(notify, 
			    SecModel, SecName, SecLevel, ContextName).


user_err(F, A) ->
    snmpa_error:user_err(F, A).
