diff options
| -rw-r--r-- | lib/diameter/include/diameter_gen.hrl | 123 |
1 files changed, 113 insertions, 10 deletions
diff --git a/lib/diameter/include/diameter_gen.hrl b/lib/diameter/include/diameter_gen.hrl index 55aae3a243..c8f706dc3e 100644 --- a/lib/diameter/include/diameter_gen.hrl +++ b/lib/diameter/include/diameter_gen.hrl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 2010-2013. All Rights Reserved. +%% Copyright Ericsson AB 2010-2014. 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 @@ -25,6 +25,11 @@ -define(THROW(T), throw({?MODULE, T})). +%% Key to a value in the process dictionary that determines whether or +%% not an unrecognized AVP setting the M-bit should be regarded as an +%% error or not. See is_strict/0. +-define(STRICT_KEY, strict). + -type parent_name() :: atom(). %% parent = Message or AVP -type parent_record() :: tuple(). %% -type avp_name() :: atom(). @@ -35,6 +40,18 @@ -type grouped_avp() :: nonempty_improper_list(#diameter_avp{}, [avp()]). -type avp() :: non_grouped_avp() | grouped_avp(). +%% Use a (hopefully) unique key when manipulating the process +%% dictionary. + +putr(K,V) -> + put({?MODULE, K}, V). + +getr(K) -> + get({?MODULE, K}). + +eraser(K) -> + erase({?MODULE, K}). + %% --------------------------------------------------------------------------- %% # encode_avps/2 %% --------------------------------------------------------------------------- @@ -212,12 +229,61 @@ decode(Name, #diameter_avp{code = Code, vendor_id = Vid} = Avp, Acc) -> %% decode/4 +%% AVP is defined in the dictionary ... decode(Name, {AvpName, Type}, Avp, Acc) -> d(Name, Avp#diameter_avp{name = AvpName, type = Type}, Acc); +%% ... or not. decode(Name, 'AVP', Avp, Acc) -> decode_AVP(Name, Avp, Acc). +%% 6733, 4.4: +%% +%% Receivers of a Grouped AVP that does not have the 'M' (mandatory) +%% bit set and one or more of the encapsulated AVPs within the group +%% has the 'M' (mandatory) bit set MAY simply be ignored if the +%% Grouped AVP itself is unrecognized. The rule applies even if the +%% encapsulated AVP with its 'M' (mandatory) bit set is further +%% encapsulated within other sub-groups, i.e., other Grouped AVPs +%% embedded within the Grouped AVP. +%% +%% The first sentence is slightly mangled, but take it to mean this: +%% +%% An unrecognized AVP of type Grouped that does not set the 'M' bit +%% MAY be ignored even if one of its encapsulated AVPs sets the 'M' +%% bit. +%% +%% The text above is a change from RFC 3588, which instead says this: +%% +%% Further, if any of the AVPs encapsulated within a Grouped AVP has +%% the 'M' (mandatory) bit set, the Grouped AVP itself MUST also +%% include the 'M' bit set. +%% +%% Both of these texts have problems. If the AVP is unknown then its +%% type is unknown since the type isn't sent over the wire, so the +%% 6733 text becomes a non-statement: don't know that the AVP not +%% setting the M-bit is of type Grouped, therefore can't know that its +%% data consists of encapsulated AVPs, therefore can't but ignore that +%% one of these might set the M-bit. It should be no worse if we know +%% the AVP to have type Grouped. +%% +%% Similarly, for the 3588 text: if we receive an AVP that doesn't set +%% the M-bit and don't know that the AVP has type Grouped then we +%% can't realize that its data contains an AVP that sets the M-bit, so +%% can't regard the AVP as erroneous on this account. Again, it should +%% be no worse if the type is known to be Grouped, but in this case +%% the RFC forces us to regard the AVP as erroneous. This is +%% inconsistent, and the 3588 text has never been enforced. +%% +%% So, if an AVP doesn't set the M-bit then we're free to ignore it, +%% regardless of the AVP's type. If we know the type to be Grouped +%% then we must ignore the M-bit on an encapsulated AVP. That means +%% packing such an encapsulated AVP into an 'AVP' field if need be, +%% not regarding the lack of a specific field as an error as is +%% otherwise the case. (The lack of an AVP-specific field being how we +%% defined the RFC's "unrecognized", which is slightly stronger than +%% "not defined".) + %% d/3 %% Don't try to decode the value of a Failed-AVP component since it @@ -230,9 +296,19 @@ d('Failed-AVP' = Name, Avp, Acc) -> %% Or try to decode. d(Name, Avp, {Avps, Acc}) -> #diameter_avp{name = AvpName, - data = Data} + data = Data, + type = Type, + is_mandatory = M} = Avp, + %% Use the process dictionary is to keep track of whether or not + %% to ignore an M-bit on an encapsulated AVP. Not ideal, but the + %% alternative requires widespread changes to be able to pass the + %% value around through the entire decode. The solution here is + %% simple in comparison, both to implement and to understand. + + Reset = relax(Type, M), + try avp(decode, Data, AvpName) of V -> {H, A} = ungroup(V, Avp), @@ -250,8 +326,32 @@ d(Name, Avp, {Avps, Acc}) -> {Reason, Avp, erlang:get_stacktrace()}), {Rec, Failed} = Acc, {[Avp|Avps], {Rec, [rc(Reason, Avp) | Failed]}} + after + relax(Reset) end. +%% Set false in the process dictionary as soon as we see a Grouped AVP +%% that doesn't set the M-bit, so that is_strict() can say whether or +%% not to ignore the M-bit on an encapsulated AVP. +relax('Grouped', M) -> + V = getr(?STRICT_KEY), + if V == undefined andalso not M -> + putr(?STRICT_KEY, M); + true -> + false + end; +relax(_, _) -> + false. + +%% Reset strictness. +relax(undefined) -> + eraser(?STRICT_KEY); +relax(false) -> + ok. + +is_strict() -> + false /= getr(?STRICT_KEY). + %% decode_AVP/3 %% %% Don't know this AVP: see if it can be packed in an 'AVP' field @@ -310,15 +410,8 @@ pack_avp(_, Arity, Avp, Acc) -> %% pack_AVP/3 -%% Give Failed-AVP special treatment since it'll contain any -%% unrecognized mandatory AVP's. -pack_AVP(Name, #diameter_avp{is_mandatory = true} = Avp, Acc) - when Name /= 'Failed-AVP' -> - {Rec, Failed} = Acc, - {Rec, [{5001, Avp} | Failed]}; - pack_AVP(Name, #diameter_avp{is_mandatory = M} = Avp, Acc) -> - case avp_arity(Name, 'AVP') of + case pack_arity(Name, M) of 0 -> {Rec, Failed} = Acc, {Rec, [{if M -> 5001; true -> 5008 end, Avp} | Failed]}; @@ -326,6 +419,16 @@ pack_AVP(Name, #diameter_avp{is_mandatory = M} = Avp, Acc) -> pack(Arity, 'AVP', Avp, Acc) end. +%% Give Failed-AVP special treatment since it'll contain any +%% unrecognized mandatory AVP's. +pack_arity(Name, M) -> + case Name /= 'Failed-AVP' andalso M andalso is_strict() of + true -> + 0; + false -> + avp_arity(Name, 'AVP') + end. + %% 3588: %% %% DIAMETER_AVP_UNSUPPORTED 5001 |