[snmp|agent] Add the default get-mechanism module snmpa_get

Added the snmpa_get module as the default get-mechanism
for the agent.
This has been done by simply moving the do_get, do_get_next
and do_get_bulk functions from the snmpa_agent module.
Some functions where also moved into the lib module (with
the idea of beeing more generally useful).

OTP-15691

1 files changed, 859 insertions, 0 deletions

diff --git a/lib/snmp/src/agent/tmp/snmpa_get.erl b/lib/snmp/src/agent/tmp/snmpa_get.erl
new file mode 100644
index 0000000000..d1710f673c
--- /dev/null
+++ b/lib/snmp/src/agent/tmp/snmpa_get.erl
@@ -0,0 +1,859 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2019-2019. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(snmpa_get).
+
+-behaviour(snmpa_get_mechanism).
+
+%%%-----------------------------------------------------------------
+%%% snmpa_get_mechanism exports
+%%%-----------------------------------------------------------------
+
+-export([
+         do_get/2, do_get/3,
+         do_get_next/2,
+         do_get_bulk/6
+        ]).
+
+%% Internal exports
+-export([do_get_next/3]).
+
+-include("snmpa_internal.hrl").
+-include("snmp_types.hrl").
+-include("snmp_debug.hrl").
+-include("snmp_verbosity.hrl").
+
+-ifndef(default_verbosity).
+-define(default_verbosity,silence).
+-endif.
+
+-define(empty_pdu_size, 21).
+
+-ifdef(snmp_extended_verbosity).
+-define(vt(F,A), ?vtrace(F, A)).
+-else.
+-define(vt(_F, _A), ok).
+-endif.
+
+
+-define(AGENT, snmpa_agent).
+-define(LIB,   snmpa_get_lib).
+
+
+
+%%% ================ GET ==========================================
+
+%%-----------------------------------------------------------------
+%% Func: do_get/2
+%% Purpose: Handles all VBs in a request that is inside the 
+%%          mibview (local).
+%% Returns: {noError, 0, ListOfNewVarbinds} |
+%%          {ErrorStatus, ErrorIndex, []}
+%%-----------------------------------------------------------------
+
+do_get(UnsortedVBs, IsNotification) ->
+    {MyIVBs, SubagentVBs} = ?LIB:sort_vbs(UnsortedVBs),
+    case do_get_local(MyIVBs, IsNotification) of
+	{noError, 0, NewMyVBs} ->
+	    case do_get_subagents(SubagentVBs, IsNotification) of
+		{noError, 0, NewSubagentVBs} ->
+		    {noError, 0, NewMyVBs ++ NewSubagentVBs};
+		{ErrorStatus, ErrorIndex, _} ->
+		    {ErrorStatus, ErrorIndex, []}
+	    end;
+	{ErrorStatus, ErrorIndex, _} -> 
+	    {ErrorStatus, ErrorIndex, []}
+    end.
+
+
+%%-----------------------------------------------------------------
+%% Func: do_get/3
+%% Purpose: do_get handles "getRequests".
+%% Pre: incoming varbinds have type == 'NULL', value == unSpecified
+%% Returns: {noError, 0, ListOfNewVarbinds} |
+%%          {ErrorStatus, ErrorIndex, []}
+%%-----------------------------------------------------------------
+
+do_get(MibView, UnsortedVBs, IsNotification) ->
+    {OutSideView, InSideView} = ?LIB:split_vbs_view(UnsortedVBs, MibView),
+    {Error, Index, NewVbs}    = do_get(InSideView, IsNotification),
+    {Error, Index, NewVbs ++ OutSideView}.
+        
+
+
+
+%%% ================ GET-NEXT =====================================
+
+%%-----------------------------------------------------------------
+%% Func: do_get_next/2
+%% Purpose: do_get_next handles "getNextRequests".
+%% Note: Even if it is SNMPv1, a varbind's value can be
+%%       endOfMibView. This is later converted to noSuchName.
+%% Returns: {noError, 0, ListOfNewVarbinds} |
+%%          {ErrorStatus, ErrorIndex, []}
+%% Note2: ListOfNewVarbinds is not sorted in any order!!!
+%% Alg: First, the variables are sorted in OID order.
+%%
+%%      Second, next in the MIB is performed for each OID, and
+%%      the result is collected as: if next oid is a variable,
+%%      perform a get to retrieve its value; if next oid is in a
+%%      table, save this value and continue until we get an oid
+%%      outside this table. Then perform get_next on the table,
+%%      and continue with all endOfTables and the oid outside the
+%%      table; if next oid is an subagent, save this value and
+%%      continue as in the table case.
+%%
+%%      Third, each response is checked for endOfMibView, or (for
+%%      subagents) that the Oid returned has the correct prefix.
+%%      (This is necessary since an SA can be registered under many
+%%      separated subtrees, and if the last variable in the first
+%%      subtree is requested in a next, the SA will return the first
+%%      variable in the second subtree. This might be working, since
+%%      there may be a variable in between these subtrees.) For each
+%%      of these, a new get-next is performed, one at a time.
+%%      This alg. might be optimised in several ways. The most 
+%%      striking one is that the same SA might be called several
+%%      times, when one time should be enough. But it isn't clear
+%%      that this really matters, since many nexts across the same
+%%      subagent must be considered to be very rare.
+%%-----------------------------------------------------------------
+
+do_get_next(MibView, UnsortedVBs) ->
+    do_get_next(MibView, UnsortedVBs, infinity).
+
+%% The third argument is only used if we are called as result
+%% of a get-buld request.
+do_get_next(_MibView, UnsortedVBs, MaxVBs)
+  when (is_list(UnsortedVBs) andalso 
+        is_integer(MaxVBs) andalso
+        (length(UnsortedVBs) > MaxVBs)) ->
+    {tooBig, 0, []};
+do_get_next(MibView, UnsortedVBs, MaxVBs) ->
+    ?vt("do_get_next -> entry when"
+ 	"~n   MibView:          ~p"
+ 	"~n   UnsortedVBs: ~p", [MibView, UnsortedVBs]),
+    SortedVBs = ?LIB:oid_sort_vbs(UnsortedVBs),
+    ?vt("do_get_next -> "
+ 	"~n   SortedVBs: ~p", [SortedVBs]),
+    next_varbinds_loop([], SortedVBs, MibView, MaxVBs, [], []).
+
+
+
+next_varbinds_loop(_, Vbs, _MibView, MaxVBs, Res, _LAVb) 
+  when (is_integer(MaxVBs) andalso 
+	((length(Vbs) + length(Res)) > MaxVBs)) ->
+    {tooBig, 0, []};
+
+%% LAVb is Last Accessible Vb
+next_varbinds_loop([], [Vb | Vbs], MibView, MaxVBs, Res, LAVb) ->
+    ?vt("next_loop_varbinds -> entry when"
+ 	"~n   Vb:      ~p"
+ 	"~n   MibView: ~p", [Vb, MibView]),
+    case varbind_next(Vb, MibView) of
+	endOfMibView ->
+	    ?vt("next_varbinds_loop -> endOfMibView", []),
+	    RVb = if LAVb =:= [] -> Vb;
+		     true -> LAVb
+		  end,
+	    NewVb = RVb#varbind{variabletype = 'NULL', value = endOfMibView},
+	    next_varbinds_loop([], Vbs, MibView, MaxVBs, [NewVb | Res], []);
+
+	{variable, ME, VarOid} when ((ME#me.access =/= 'not-accessible') andalso 
+				     (ME#me.access =/= 'write-only') andalso 
+				     (ME#me.access =/= 'accessible-for-notify')) -> 
+	    ?vt("next_varbinds_loop -> variable: "
+		"~n   ME:     ~p"
+		"~n   VarOid: ~p", [ME, VarOid]),
+	    case ?LIB:try_get_instance(Vb, ME) of
+		{value, noValue, _NoSuchSomething} ->
+		    ?vt("next_varbinds_loop -> noValue", []),
+		    %% Try next one
+		    NewVb = Vb#varbind{oid   = VarOid, 
+				       value = 'NULL'},
+		    next_varbinds_loop([], [NewVb | Vbs], MibView, MaxVBs, Res, []);
+		{value, Type, Value} ->
+		    ?vt("next_varbinds_loop -> value"
+			"~n   Type:  ~p"
+			"~n   Value: ~p", [Type, Value]),
+		    NewVb = Vb#varbind{oid          = VarOid, 
+				       variabletype = Type,
+				       value        = Value},
+		    next_varbinds_loop([], Vbs, MibView, MaxVBs,
+                                       [NewVb | Res], []);
+		{error, ErrorStatus} ->
+		    ?vdebug("next varbinds loop:"
+			    "~n   ErrorStatus: ~p",[ErrorStatus]),
+		    {ErrorStatus, Vb#varbind.org_index, []}
+	    end;
+	{variable, _ME, VarOid} -> 
+	    ?vt("next_varbinds_loop -> variable: "
+		"~n   VarOid: ~p", [VarOid]),
+	    RVb = if LAVb =:= [] -> Vb;
+		     true -> LAVb
+		  end,
+	    NewVb = Vb#varbind{oid = VarOid, value = 'NULL'},
+	    next_varbinds_loop([], [NewVb | Vbs], MibView, MaxVBs, Res, RVb);
+	{table, TableOid, TableRestOid, ME} ->
+	    ?vt("next_varbinds_loop -> table: "
+		"~n   TableOid:     ~p"
+		"~n   TableRestOid: ~p"
+		"~n   ME:           ~p", [TableOid, TableRestOid, ME]),
+	    next_varbinds_loop({table, TableOid, ME,
+				[{?LIB:tab_oid(TableRestOid), Vb}]},
+			       Vbs, MibView, MaxVBs, Res, []);
+	{subagent, SubAgentPid, SAOid} ->
+	    ?vt("next_varbinds_loop -> subagent: "
+		"~n   SubAgentPid: ~p"
+		"~n   SAOid:       ~p", [SubAgentPid, SAOid]),
+	    NewVb = Vb#varbind{variabletype = 'NULL', value = 'NULL'},
+	    next_varbinds_loop({subagent, SubAgentPid, SAOid, [NewVb]},
+			       Vbs, MibView, MaxVBs, Res, [])
+    end;
+
+next_varbinds_loop({table, TableOid, ME, TabOids},
+		   [Vb | Vbs], MibView, MaxVBs, Res, _LAVb) ->
+    ?vt("next_varbinds_loop(table) -> entry with"
+ 	"~n   TableOid: ~p"
+ 	"~n   Vb:       ~p", [TableOid, Vb]),
+    case varbind_next(Vb, MibView) of
+	{table, TableOid, TableRestOid, _ME} ->
+	    next_varbinds_loop({table, TableOid, ME,
+				[{?LIB:tab_oid(TableRestOid), Vb} | TabOids]},
+			       Vbs, MibView, MaxVBs, Res, []);
+	_ ->
+	    case get_next_table(ME, TableOid, TabOids, MibView) of
+		{ok, TabRes, TabEndOfTabVbs} ->
+		    NewVbs = lists:append(TabEndOfTabVbs, [Vb | Vbs]),
+		    NewRes = lists:append(TabRes, Res),
+		    next_varbinds_loop([], NewVbs, MibView, MaxVBs, NewRes, []);
+		{ErrorStatus, OrgIndex} ->
+		    ?vdebug("next varbinds loop: next varbind"
+			    "~n   ErrorStatus: ~p"
+			    "~n   OrgIndex:    ~p",
+			    [ErrorStatus,OrgIndex]),
+		    {ErrorStatus, OrgIndex, []}
+	    end
+    end;
+next_varbinds_loop({table, TableOid, ME, TabOids},
+                   [], MibView, MaxVBs, Res, _LAVb) ->
+    ?vt("next_varbinds_loop(table) -> entry with"
+	"~n   TableOid: ~p", [TableOid]),
+    case get_next_table(ME, TableOid, TabOids, MibView) of
+	{ok, TabRes, TabEndOfTabVbs} ->
+ 	    ?vt("next_varbinds_loop(table) -> get_next_table result:"
+		"~n   TabRes:         ~p"
+		"~n   TabEndOfTabVbs: ~p", [TabRes, TabEndOfTabVbs]),
+	    NewRes = lists:append(TabRes, Res),
+	    next_varbinds_loop([], TabEndOfTabVbs, MibView, MaxVBs, NewRes, []);
+	{ErrorStatus, OrgIndex} ->
+	    ?vdebug("next varbinds loop: next table"
+		    "~n   ErrorStatus: ~p"
+		    "~n   OrgIndex:    ~p",
+		    [ErrorStatus,OrgIndex]),
+	    {ErrorStatus, OrgIndex, []}
+    end;
+
+next_varbinds_loop({subagent, SAPid, SAOid, SAVbs},
+		   [Vb | Vbs], MibView, MaxVBs, Res, _LAVb) ->
+    ?vt("next_varbinds_loop(subagent) -> entry with"
+	"~n   SAPid: ~p"
+	"~n   SAOid: ~p"
+ 	"~n   Vb:    ~p", [SAPid, SAOid, Vb]),
+    case varbind_next(Vb, MibView) of
+	{subagent, _SubAgentPid, SAOid} ->
+	    next_varbinds_loop({subagent, SAPid, SAOid,
+				[Vb | SAVbs]},
+			       Vbs, MibView, MaxVBs, Res, []);
+	_ ->
+	    case get_next_sa(SAPid, SAOid, SAVbs, MibView) of
+		{ok, SARes, SAEndOfMibViewVbs} ->
+		    NewVbs = lists:append(SAEndOfMibViewVbs, [Vb | Vbs]),
+		    NewRes = lists:append(SARes, Res),
+		    next_varbinds_loop([], NewVbs, MibView, MaxVBs, NewRes, []);
+		{noSuchName, OrgIndex} ->
+		    %% v1 reply, treat this Vb as endOfMibView, and try again
+		    %% for the others.
+		    case lists:keysearch(OrgIndex, #varbind.org_index, SAVbs) of
+			{value, EVb} ->
+			    NextOid = ?LIB:next_oid(SAOid),
+			    EndOfVb = 
+				EVb#varbind{oid = NextOid,
+					    value = {endOfMibView, NextOid}},
+			    case lists:delete(EVb, SAVbs) of
+				[] ->
+				    next_varbinds_loop([], [EndOfVb, Vb | Vbs],
+						       MibView, Res, [],
+						       MaxVBs);
+				TryAgainVbs ->
+				    next_varbinds_loop({subagent, SAPid, SAOid,
+							TryAgainVbs},
+						       [EndOfVb, Vb | Vbs],
+						       MibView, Res, [],
+                                                       MaxVBs)
+			    end;
+			false ->
+			    %% bad index from subagent
+			    {genErr, (hd(SAVbs))#varbind.org_index, []}
+		    end;
+		{ErrorStatus, OrgIndex} ->
+ 		    ?vdebug("next varbinds loop: next subagent"
+ 			    "~n   Vb:          ~p"
+ 			    "~n   ErrorStatus: ~p"
+ 			    "~n   OrgIndex:    ~p",
+ 			    [Vb,ErrorStatus,OrgIndex]),
+		    {ErrorStatus, OrgIndex, []}
+	    end
+    end;
+next_varbinds_loop({subagent, SAPid, SAOid, SAVbs},
+		   [], MibView, GbMaxVBs, Res, _LAVb) ->
+    ?vt("next_varbinds_loop(subagent) -> entry with"
+	 "~n   SAPid: ~p"
+	 "~n   SAOid: ~p", [SAPid, SAOid]),
+    case get_next_sa(SAPid, SAOid, SAVbs, MibView) of
+	{ok, SARes, SAEndOfMibViewVbs} ->
+	    NewRes = lists:append(SARes, Res),
+	    next_varbinds_loop([], SAEndOfMibViewVbs, MibView, GbMaxVBs,
+                               NewRes, []);
+	{noSuchName, OrgIndex} ->
+	    %% v1 reply, treat this Vb as endOfMibView, and try again for
+	    %% the others.
+	    case lists:keysearch(OrgIndex, #varbind.org_index, SAVbs) of
+		{value, EVb} ->
+		    NextOid = ?LIB:next_oid(SAOid),
+		    EndOfVb = EVb#varbind{oid = NextOid,
+					  value = {endOfMibView, NextOid}},
+		    case lists:delete(EVb, SAVbs) of
+			[] ->
+			    next_varbinds_loop([], [EndOfVb], MibView, 
+                                               GbMaxVBs, Res, []);
+			TryAgainVbs ->
+			    next_varbinds_loop({subagent, SAPid, SAOid,
+						TryAgainVbs},
+					       [EndOfVb], MibView, GbMaxVBs,
+                                               Res, [])
+		    end;
+		false ->
+		    %% bad index from subagent
+		    {genErr, (hd(SAVbs))#varbind.org_index, []}
+	    end;
+	{ErrorStatus, OrgIndex} ->
+ 	    ?vdebug("next varbinds loop: next subagent"
+ 		    "~n   ErrorStatus: ~p"
+ 		    "~n   OrgIndex:    ~p",
+ 		    [ErrorStatus,OrgIndex]),
+ 	    {ErrorStatus, OrgIndex, []}
+    end;
+
+next_varbinds_loop([], [], _MibView, _GbMaxVBs, Res, _LAVb) ->
+    ?vt("next_varbinds_loop -> entry when done", []),
+    {noError, 0, Res}.
+
+
+%%-----------------------------------------------------------------
+%% Perform a next, using the varbinds Oid if value is simple
+%% value. If value is {endOf<something>, NextOid}, use NextOid.
+%% This case happens when a table has returned endOfTable, or
+%% a subagent has returned endOfMibView.
+%%-----------------------------------------------------------------
+varbind_next(#varbind{value = Value, oid = Oid}, MibView) ->
+    ?vt("varbind_next -> entry with"
+ 	"~n   Value:   ~p"
+ 	"~n   Oid:     ~p"
+ 	"~n   MibView: ~p", [Value, Oid, MibView]),
+    case Value of
+	{endOfTable, NextOid} ->
+	    snmpa_mib:next(get(mibserver), NextOid, MibView);
+	{endOfMibView, NextOid} ->
+	    snmpa_mib:next(get(mibserver), NextOid, MibView);
+	_ ->
+	    snmpa_mib:next(get(mibserver), Oid, MibView)
+    end.
+
+
+get_next_table(#me{mfa = {M, F, A}}, TableOid, TableOids, MibView) ->
+    % We know that all TableOids have at least a column number as oid
+    ?vt("get_next_table -> entry with"
+	"~n   M:         ~p"
+	"~n   F:         ~p"
+	"~n   A:         ~p"
+	"~n   TableOid:  ~p"
+	"~n   TableOids: ~p"
+	"~n   MibView:   ~p", [M, F, A, TableOid, TableOids, MibView]),
+    Sorted = snmpa_svbl:sort_varbinds_rows(TableOids),
+    case get_next_values_all_rows(Sorted, M,F,A, [], TableOid) of
+	NewVbs when is_list(NewVbs) ->
+ 	    ?vt("get_next_table -> "
+		"~n   NewVbs: ~p", [NewVbs]),
+	    % We must now check each Vb for endOfTable and that it is
+	    % in the MibView. If not, it becomes a endOfTable. We 
+	    % collect all of these together.
+	    transform_tab_next_result(NewVbs, {[], []}, MibView);
+	{ErrorStatus, OrgIndex} ->
+	    {ErrorStatus, OrgIndex}
+    end.
+
+
+get_next_values_all_rows([], _M, _F, _A, Res, _TabOid) ->
+    Res;
+get_next_values_all_rows([Row | Rows], M, F, A, Res, TabOid) ->
+    {RowIndex, TableOids} = Row,
+    Cols = ?LIB:delete_index(TableOids),
+    ?vt("get_next_values_all_rows -> "
+	"~n   Cols: ~p", [Cols]),
+    Result = (catch ?LIB:dbg_apply(M, F, [get_next, RowIndex, Cols | A])),
+    ?vt("get_next_values_all_rows -> "
+ 	"~n   Result: ~p", [Result]),
+    case validate_tab_next_res(Result, TableOids, {M, F, A}, TabOid) of
+	Values when is_list(Values) -> 
+ 	    ?vt("get_next_values_all_rows -> "
+ 		"~n   Values: ~p", [Values]),
+	    NewRes = lists:append(Values, Res),
+	    get_next_values_all_rows(Rows, M, F, A, NewRes, TabOid);
+	{ErrorStatus, OrgIndex} ->
+	    {ErrorStatus, OrgIndex}
+    end.
+
+transform_tab_next_result([Vb | Vbs], {Res, EndOfs}, MibView) ->
+    case Vb#varbind.value of
+	{endOfTable, _} ->
+	    ?LIB:split_vbs(Vbs, Res, [Vb | EndOfs]);
+	_ ->
+	    case snmpa_acm:validate_mib_view(Vb#varbind.oid, MibView) of
+		true ->
+		    transform_tab_next_result(Vbs, {[Vb|Res], EndOfs},MibView);
+		_ ->
+		    Oid = Vb#varbind.oid,
+		    NewEndOf = Vb#varbind{value = {endOfTable, Oid}},
+		    transform_tab_next_result(Vbs, {Res, [NewEndOf | EndOfs]},
+					      MibView)
+	    end
+    end;
+transform_tab_next_result([], {Res, EndOfs}, _MibView) ->
+    ?vt("transform_tab_next_result -> entry with: "
+ 	"~n   Res:    ~p"
+ 	"~n   EndIfs: ~p",[Res, EndOfs]),
+    {ok, Res, EndOfs}.
+
+
+%%-----------------------------------------------------------------
+%% Three cases:
+%%   1) All values ok
+%%   2) table_func returned {Error, ...}
+%%   3) Some value in Values list is erroneous.
+%% Args: Value is a list of values from table_func(get_next, ...)
+%%       TableOids is a list of {TabRestOid, OrgVb} 
+%%         each element in Values and TableOids correspond to each
+%%         other.
+%% Returns: List of NewVarbinds |
+%%          {ErrorStatus, OrgIndex}
+%%          (In the NewVarbinds list, the value may be endOfTable)
+%%-----------------------------------------------------------------
+validate_tab_next_res(Values, TableOids, Mfa, TabOid) ->
+     ?vt("validate_tab_next_res -> entry with: "
+	 "~n   Values:     ~p"
+	 "~n   TableOids:  ~p"
+	 "~n   Mfa:        ~p"
+	 "~n   TabOid:     ~p", [Values, TableOids, Mfa, TabOid]),
+    {_Col, _ASN1Type, OneIdx} = hd(TableOids),
+    validate_tab_next_res(Values, TableOids, Mfa, [], TabOid,
+			  ?LIB:next_oid(TabOid), OneIdx).
+validate_tab_next_res([{NextOid, Value} | Values],
+		      [{_ColNo, OrgVb, _Index} | TableOids],
+		      Mfa, Res, TabOid, TabNextOid, I) ->
+    ?vt("validate_tab_next_res -> entry with: "
+ 	"~n   NextOid:    ~p"
+ 	"~n   Value:      ~p"
+ 	"~n   Values:     ~p"
+ 	"~n   TableOids:  ~p"
+ 	"~n   Mfa:        ~p"
+ 	"~n   TabOid:     ~p", 
+ 	[NextOid, Value, Values, TableOids, Mfa, TabOid]),
+    #varbind{org_index = OrgIndex} = OrgVb,
+    ?vt("validate_tab_next_res -> OrgIndex: ~p", [OrgIndex]),
+    NextCompleteOid = lists:append(TabOid, NextOid),
+    case snmpa_mib:lookup(get(mibserver), NextCompleteOid) of
+	{table_column, #me{asn1_type = ASN1Type}, _TableEntryOid} ->
+  	    ?vt("validate_tab_next_res -> ASN1Type: ~p", [ASN1Type]),
+	    case ?LIB:make_value_a_correct_value({value, Value}, ASN1Type, Mfa) of
+		{error, ErrorStatus} ->
+ 		    ?vt("validate_tab_next_res -> "
+ 			"~n   ErrorStatus: ~p", [ErrorStatus]),
+		    {ErrorStatus, OrgIndex};
+		{value, Type, NValue} ->
+ 		    ?vt("validate_tab_next_res -> "
+     			"~n   Type:   ~p"
+			"~n   NValue: ~p", [Type, NValue]),
+		    NewVb = OrgVb#varbind{oid = NextCompleteOid,
+					  variabletype = Type, value = NValue},
+		    validate_tab_next_res(Values, TableOids, Mfa,
+					  [NewVb | Res], TabOid, TabNextOid, I)
+	    end;
+	Error ->
+	    ?LIB:user_err("Invalid oid ~w from ~w (get_next). Using genErr => ~p",
+		     [NextOid, Mfa, Error]),
+	    {genErr, OrgIndex}
+    end;
+validate_tab_next_res([endOfTable | Values],
+		      [{_ColNo, OrgVb, _Index} | TableOids],
+		      Mfa, Res, TabOid, TabNextOid, I) ->
+     ?vt("validate_tab_next_res(endOfTable) -> entry with: "
+	 "~n   Values:     ~p"
+	 "~n   OrgVb:      ~p"
+	 "~n   TableOids:  ~p"
+	 "~n   Mfa:        ~p"
+	 "~n   Res:        ~p"
+	 "~n   TabOid:     ~p"
+	 "~n   TabNextOid: ~p"
+	 "~n   I:          ~p",
+	 [Values, OrgVb, TableOids, Mfa, Res, TabOid, TabNextOid, I]),
+    NewVb = OrgVb#varbind{value = {endOfTable, TabNextOid}},
+    validate_tab_next_res(Values, TableOids, Mfa, [NewVb | Res],
+			  TabOid, TabNextOid, I);
+validate_tab_next_res([], [], _Mfa, Res, _TabOid, _TabNextOid, _I) ->
+    Res;
+validate_tab_next_res([], [{_Col, _OrgVb, Index}|_], Mfa, _Res, _, _, _I) ->
+    ?LIB:user_err("Too few values returned from ~w (get_next)", [Mfa]),
+    {genErr, Index};
+validate_tab_next_res({genErr, ColNumber}, OrgCols,
+		      Mfa, _Res, _TabOid, _TabNextOid, _I) ->
+    OrgIndex = snmpa_svbl:col_to_orgindex(ColNumber, OrgCols),
+    ?AGENT:validate_err(table_next, {genErr, OrgIndex}, Mfa);
+validate_tab_next_res({error, Reason}, [{_ColNo, OrgVb, _Index} | _TableOids],
+		      Mfa, _Res, _TabOid, _TabNextOid, _I) ->
+    #varbind{org_index = OrgIndex} = OrgVb,
+    ?LIB:user_err("Erroneous return value ~w from ~w (get_next)",
+	     [Reason, Mfa]),
+    {genErr, OrgIndex};
+validate_tab_next_res(Error, [{_ColNo, OrgVb, _Index} | _TableOids],
+		      Mfa, _Res, _TabOid, _TabNextOid, _I) ->
+    #varbind{org_index = OrgIndex} = OrgVb,
+    ?LIB:user_err("Invalid return value ~w from ~w (get_next)",
+                  [Error, Mfa]),
+    {genErr, OrgIndex};
+validate_tab_next_res(TooMany, [], Mfa, _Res, _, _, I) ->
+    ?LIB:user_err("Too many values ~w returned from ~w (get_next)",
+                  [TooMany, Mfa]),
+    {genErr, I}.
+
+
+%%-----------------------------------------------------------------
+%% Func: get_next_sa/4
+%% Purpose: Loop the list of varbinds for the subagent.
+%%          Call subagent_get_next to retreive
+%%          the next varbinds.
+%% Returns: {ok, ListOfNewVbs, ListOfEndOfMibViewsVbs} |
+%%          {ErrorStatus, ErrorIndex}
+%%-----------------------------------------------------------------
+get_next_sa(SAPid, SAOid, SAVbs, MibView) ->
+    case catch subagent_get_next(SAPid, MibView, SAVbs) of
+	{noError, 0, NewVbs} ->
+	    NewerVbs = transform_sa_next_result(NewVbs, SAOid,
+                                                ?LIB:next_oid(SAOid)),
+	    ?LIB:split_vbs(NewerVbs);
+	{ErrorStatus, ErrorIndex, _} ->
+	    {ErrorStatus, ErrorIndex};
+	{'EXIT', Reason} ->
+	    ?LIB:user_err("Lost contact with subagent (next) ~w. Using genErr",
+                          [Reason]),
+	    {genErr, 0}
+    end.
+
+
+%%-----------------------------------------------------------------
+%% Check for wrong prefix returned or endOfMibView, and convert
+%% into {endOfMibView, SANextOid}.
+%%-----------------------------------------------------------------
+transform_sa_next_result([Vb | Vbs], SAOid, SANextOid)
+  when Vb#varbind.value =:= endOfMibView ->
+    [Vb#varbind{value = {endOfMibView, SANextOid}} |
+     transform_sa_next_result(Vbs, SAOid, SANextOid)];
+transform_sa_next_result([Vb | Vbs], SAOid, SANextOid) ->
+    case lists:prefix(SAOid, Vb#varbind.oid) of
+	true ->
+	    [Vb | transform_sa_next_result(Vbs, SAOid, SANextOid)];
+	_ ->
+	    [Vb#varbind{oid = SANextOid, value = {endOfMibView, SANextOid}} |
+	     transform_sa_next_result(Vbs, SAOid, SANextOid)]
+    end;
+transform_sa_next_result([], _SAOid, _SANextOid) ->
+    [].
+
+
+
+%%% ================ GET-BULK =====================================
+%%%
+%%% In order to prevent excesses in reply sizes there are two 
+%%% preventive methods in place. One is to check that the encode
+%%% size does not exceed Max PDU size (this is mentioned in the
+%%% standard). The other is a simple VBs limit. That is, the 
+%%% resulting response cannot contain more then this number of VBs.
+%%%
+
+do_get_bulk(MibView, NonRepeaters, MaxRepetitions, PduMS, Varbinds, GbMaxVBs) ->
+    ?vtrace("do_get_bulk -> entry with"
+	    "~n   MibView:        ~p"
+	    "~n   NonRepeaters:   ~p"
+	    "~n   MaxRepetitions: ~p"
+	    "~n   PduMS:          ~p"
+	    "~n   Varbinds:       ~p"
+	    "~n   GbMaxVBs:       ~p",
+	    [MibView, NonRepeaters, MaxRepetitions, PduMS, Varbinds, GbMaxVBs]),
+    {NonRepVbs, RestVbs} = ?LIB:split_gb_vbs(NonRepeaters, Varbinds),
+    ?vt("do_get_bulk -> split: "
+	"~n   NonRepVbs: ~p"
+	"~n   RestVbs:   ~p", [NonRepVbs, RestVbs]),
+    case do_get_next(MibView, NonRepVbs, GbMaxVBs) of
+	{noError, 0, UResNonRepVbs} ->
+	    ?vt("do_get_bulk -> next noError: "
+		"~n   UResNonRepVbs: ~p", [UResNonRepVbs]),
+	    ResNonRepVbs = lists:keysort(#varbind.org_index, UResNonRepVbs),
+	    %% Decode the first varbinds, produce a reversed list of
+	    %% listOfBytes.
+	    case (catch enc_vbs(PduMS - ?empty_pdu_size, ResNonRepVbs)) of
+ 		{error, Idx, Reason} ->
+		    ?LIB:user_err("failed encoding varbind ~w:~n~p", [Idx, Reason]),
+                    {genErr, Idx, []};
+                {SizeLeft, Res} when is_integer(SizeLeft) and is_list(Res) ->
+ 		    ?vtrace("do_get_bulk -> encoded: "
+			    "~n   SizeLeft: ~p"
+			    "~n   Res:      ~w", [SizeLeft, Res]),
+		    case (catch do_get_rep(SizeLeft, MibView, MaxRepetitions,
+					   RestVbs, Res, 
+					   length(UResNonRepVbs), GbMaxVBs)) of
+			{error, Idx, Reason} ->
+			    ?LIB:user_err("failed encoding varbind ~w:~n~p", 
+                                          [Idx, Reason]),
+			    {genErr, Idx, []};
+			Res when is_list(Res) ->
+			    ?vtrace("do get bulk -> Res: "
+				    "~n   ~w", [Res]),
+			    {noError, 0, conv_res(Res)};
+			{noError, 0, Data} = OK ->
+			    ?vtrace("do get bulk -> OK: "
+				    "~n   length(Data): ~w", [length(Data)]),
+			    OK;
+			Else ->
+			    ?vtrace("do get bulk -> Else: "
+				    "~n   ~w", [Else]),
+			    Else
+		    end;
+		Res when is_list(Res) ->
+		    {noError, 0, conv_res(Res)}
+	    end;
+
+	{ErrorStatus, Index, _} ->
+	    ?vdebug("do get bulk: "
+		    "~n   ErrorStatus: ~p"
+		    "~n   Index:       ~p",[ErrorStatus, Index]),
+	    {ErrorStatus, Index, []}
+    end.
+
+
+enc_vbs(SizeLeft, Vbs) ->
+    ?vt("enc_vbs -> entry with"
+	"~n   SizeLeft: ~w", [SizeLeft]),
+    Fun = fun(Vb, {Sz, Res}) when Sz > 0 ->
+		  ?vt("enc_vbs -> (fun) entry with"
+		      "~n   Vb:  ~p"
+		      "~n   Sz:  ~p"
+		      "~n   Res: ~w", [Vb, Sz, Res]),
+		  case (catch snmp_pdus:enc_varbind(Vb)) of
+		      {'EXIT', Reason} ->
+			  ?vtrace("enc_vbs -> encode failed: "
+				  "~n   Reason: ~p", [Reason]),
+			  throw({error, Vb#varbind.org_index, Reason});
+		      X ->
+			  ?vt("enc_vbs -> X: ~w", [X]),
+			  Lx = length(X),
+			  ?vt("enc_vbs -> Lx: ~w", [Lx]),
+			  if
+			      Lx < Sz ->
+				  {Sz - length(X), [X | Res]};
+			      true ->
+				  throw(Res)
+			  end
+		  end;
+	     (_Vb, {_Sz, [_H | T]}) ->
+		  ?vt("enc_vbs -> (fun) entry with"
+		      "~n   T: ~p", [T]),
+		  throw(T);
+	     (_Vb, {_Sz, []}) ->
+		  ?vt("enc_vbs -> (fun) entry", []),
+		  throw([])
+	  end,
+    lists:foldl(Fun, {SizeLeft, []}, Vbs).
+
+do_get_rep(Sz, MibView, MaxRepetitions, Varbinds, Res, GbNumVBs, GbMaxVBs) 
+  when MaxRepetitions >= 0 ->
+    do_get_rep(Sz, MibView, 0, MaxRepetitions, Varbinds, Res, 
+	       GbNumVBs, GbMaxVBs);
+do_get_rep(Sz, MibView, _MaxRepetitions, Varbinds, Res, GbNumVBs, GbMaxVBs) ->
+    do_get_rep(Sz, MibView, 0, 0, Varbinds, Res, GbNumVBs, GbMaxVBs).
+
+conv_res(ResVarbinds) ->
+    conv_res(ResVarbinds, []).
+conv_res([VbListOfBytes | T], Bytes) ->
+    conv_res(T, VbListOfBytes ++ Bytes);
+conv_res([], Bytes) ->
+    Bytes.
+
+%% The only other value, then a positive integer, is infinity.
+do_get_rep(_Sz, _MibView, Count, Max, _, _Res, GbNumVBs, GbMaxVBs) 
+  when (is_integer(GbMaxVBs) andalso (GbNumVBs > GbMaxVBs)) ->
+    ?vinfo("Max Get-BULK VBs limit (~w) exceeded (~w) when:"
+	   "~n   Count: ~p"
+	   "~n   Max:   ~p", [GbMaxVBs, GbNumVBs, Count, Max]),
+    {tooBig, 0, []};
+do_get_rep(_Sz, _MibView, Max, Max, _, Res, _GbNumVBs, _GbMaxVBs) ->
+    ?vt("do_get_rep -> done when: "
+	"~n   Res: ~p", [Res]),
+    {noError, 0, conv_res(Res)};
+do_get_rep(Sz, MibView, Count, Max, Varbinds, Res, GbNumVBs, GbMaxVBs) -> 
+    ?vt("do_get_rep -> entry when: "
+	"~n   Sz:    ~p"
+	"~n   Count: ~p"
+	"~n   Res:   ~w", [Sz, Count, Res]),
+    case try_get_bulk(Sz, MibView, Varbinds, GbMaxVBs) of
+	{noError, NextVarbinds, SizeLeft, Res2} -> 
+	    ?vt("do_get_rep -> noError: "
+		"~n   SizeLeft: ~p"
+		"~n   Res2:     ~p", [SizeLeft, Res2]),
+	    do_get_rep(SizeLeft, MibView, Count+1, Max, NextVarbinds,
+		       Res2 ++ Res, 
+		       GbNumVBs + length(Varbinds), GbMaxVBs);
+	{endOfMibView, _NextVarbinds, _SizeLeft, Res2} -> 
+	    ?vt("do_get_rep -> endOfMibView: "
+		"~n   Res2: ~p", [Res2]),
+	    {noError, 0, conv_res(Res2 ++ Res)};
+	{ErrorStatus, Index} ->
+	    ?vtrace("do_get_rep -> done when error: "
+		    "~n   ErrorStatus: ~p"
+		    "~n   Index:       ~p", [ErrorStatus, Index]),
+	    {ErrorStatus, Index, []}
+    end.
+
+org_index_sort_vbs(Vbs) ->
+    lists:keysort(#varbind.org_index, Vbs).
+
+try_get_bulk(Sz, MibView, Varbinds, GbMaxVBs) -> 
+    ?vt("try_get_bulk -> entry with"
+	"~n   Sz:       ~w"
+	"~n   MibView:  ~w"
+	"~n   Varbinds: ~w", [Sz, MibView, Varbinds]),
+    case do_get_next(MibView, Varbinds, GbMaxVBs) of
+	{noError, 0, UNextVarbinds} -> 
+	    ?vt("try_get_bulk -> noError: "
+		"~n   UNextVarbinds: ~p", [UNextVarbinds]),
+	    NextVarbinds = org_index_sort_vbs(UNextVarbinds),
+	    case (catch enc_vbs(Sz, NextVarbinds)) of
+		{error, Idx, Reason} ->
+		    ?LIB:user_err("failed encoding varbind ~w:~n~p", [Idx, Reason]),
+		    ?vtrace("try_get_bulk -> encode error: "
+			    "~n   Idx:    ~p"
+			    "~n   Reason: ~p", [Idx, Reason]),
+		    {genErr, Idx};
+		{SizeLeft, Res} when is_integer(SizeLeft) andalso 
+				     is_list(Res) ->
+		    ?vt("try get bulk -> encode ok: "
+			"~n   SizeLeft: ~w"
+			"~n   Res:      ~w", [SizeLeft, Res]),
+		    {check_end_of_mibview(NextVarbinds),
+		     NextVarbinds, SizeLeft, Res};
+		Res when is_list(Res) ->
+		    ?vt("try get bulk -> Res: "
+			"~n   ~w", [Res]),
+		    {endOfMibView, [], 0, Res}
+	    end;
+	{ErrorStatus, Index, _} ->
+	    ?vt("try_get_bulk -> error: "
+		"~n   ErrorStatus: ~p"
+		"~n   Index:       ~p", [ErrorStatus, Index]),
+	    {ErrorStatus, Index}
+    end.
+
+%% If all variables in this pass are endOfMibView,
+%% there is no reason to continue.
+check_end_of_mibview([#varbind{value = endOfMibView} | T]) ->
+    check_end_of_mibview(T);
+check_end_of_mibview([]) ->
+    endOfMibView;
+check_end_of_mibview(_) ->
+    noError.
+
+
+
+%%-----------------------------------------------------------------
+%% Internal
+%%-----------------------------------------------------------------
+
+%%-----------------------------------------------------------------
+%% Func: do_get_local/2
+%% Purpose: Loop the variablebindings list. We know that each varbind
+%%          in that list belongs to us.
+%% Returns: {noError, 0, ListOfNewVarbinds} |
+%%          {ErrorStatus, ErrorIndex, []}
+%%-----------------------------------------------------------------
+
+do_get_local(IVBs, IsNotification) ->
+    do_get_local(IVBs, IsNotification, []).
+
+do_get_local([], _IsNotification, Res) -> 
+    {noError, 0, Res};
+do_get_local([IVB | IVBs], IsNotification, Res) ->
+    case ?LIB:try_get(IVB, IsNotification) of
+	NewVB when is_record(NewVB, varbind) ->
+	    do_get_local(IVBs, IsNotification, [NewVB | Res]);
+	NewVBs when is_list(NewVBs) ->
+	    do_get_local(IVBs, IsNotification, lists:append(NewVBs, Res));
+	{error, Error, OrgIndex} ->
+	    {Error, OrgIndex, []}
+    end.
+
+
+%%-----------------------------------------------------------------
+%% Func: do_get_subagents/2
+%% Purpose: Loop the list of varbinds for different subagents.
+%%          For each of them, call subagent_get to retreive
+%%          the values for them.
+%% Returns: {noError, 0, ListOfNewVarbinds} |
+%%          {ErrorStatus, ErrorIndex, []}
+%%-----------------------------------------------------------------
+
+do_get_subagents(SubagentVarbinds, IsNotification) ->
+    do_get_subagents(SubagentVarbinds, IsNotification, []).
+
+do_get_subagents([], _IsNotification, Res) ->
+    {noError, 0, Res};
+do_get_subagents([{SAPid, SAVBs} | Tail], IsNotification, Res) ->
+    {_SAOids, VBs} = ?LIB:sa_split(SAVBs),
+    case (catch subagent_get(SAPid, IsNotification, VBs)) of
+	{noError, 0, NewVBs} ->
+	    do_get_subagents(Tail, IsNotification, lists:append(NewVBs, Res));
+	{ErrorStatus, ErrorIndex, _} ->
+	    {ErrorStatus, ErrorIndex, []};
+	{'EXIT', Reason} ->
+	    ?LIB:user_err("Lost contact with subagent (get) ~w. Using genErr", 
+                          [Reason]),
+	    {genErr, 0, []} 
+    end.
+
+
+
+