diff options
Diffstat (limited to 'lib/diameter/include/diameter_gen.hrl')
| -rw-r--r-- | lib/diameter/include/diameter_gen.hrl | 187 |
1 files changed, 143 insertions, 44 deletions
diff --git a/lib/diameter/include/diameter_gen.hrl b/lib/diameter/include/diameter_gen.hrl index c8f706dc3e..bc25f7d472 100644 --- a/lib/diameter/include/diameter_gen.hrl +++ b/lib/diameter/include/diameter_gen.hrl @@ -30,6 +30,10 @@ %% error or not. See is_strict/0. -define(STRICT_KEY, strict). +%% Key that says whether or not we should do a best-effort decode +%% within Failed-AVP. +-define(FAILED_KEY, failed). + -type parent_name() :: atom(). %% parent = Message or AVP -type parent_record() :: tuple(). %% -type avp_name() :: atom(). @@ -286,15 +290,7 @@ decode(Name, 'AVP', Avp, Acc) -> %% d/3 -%% Don't try to decode the value of a Failed-AVP component since it -%% probably won't. Note that matching on 'Failed-AVP' assumes that -%% this is the RFC AVP, with code 279. Strictly, this doesn't need to -%% be the case, so we're assuming no one defines another Failed-AVP. -d('Failed-AVP' = Name, Avp, Acc) -> - decode_AVP(Name, Avp, Acc); - -%% Or try to decode. -d(Name, Avp, {Avps, Acc}) -> +d(Name, Avp, Acc) -> #diameter_avp{name = AvpName, data = Data, type = Type, @@ -307,51 +303,120 @@ d(Name, Avp, {Avps, Acc}) -> %% value around through the entire decode. The solution here is %% simple in comparison, both to implement and to understand. - Reset = relax(Type, M), + Strict = relax(Type, M), + + %% Use the process dictionary again to keep track of whether we're + %% decoding within Failed-AVP and should ignore decode errors + %% altogether. + + Failed = relax(Name), %% Not AvpName or else a failed Failed-AVP + %% decode is packed into 'AVP'. + Mod = dict(Failed), %% Dictionary to decode in. - try avp(decode, Data, AvpName) of + try Mod:avp(decode, Data, AvpName) of V -> + {Avps, T} = Acc, {H, A} = ungroup(V, Avp), - {[H | Avps], pack_avp(Name, A, Acc)} + {[H | Avps], pack_avp(Name, A, T)} catch error: Reason -> - %% Failures here won't be visible since they're a "normal" - %% occurrence if the peer sends a faulty AVP that we need to - %% respond sensibly to. Log the occurence for traceability, - %% but the peer will also receive info in the resulting - %% answer-message. - diameter_lib:log({decode, failure}, - ?MODULE, - ?LINE, - {Reason, Avp, erlang:get_stacktrace()}), - {Rec, Failed} = Acc, - {[Avp|Avps], {Rec, [rc(Reason, Avp) | Failed]}} + d(undefined == Failed orelse is_failed(), + Reason, + Name, + trim(Avp), + Acc) after - relax(Reset) + reset(?STRICT_KEY, Strict), + reset(?FAILED_KEY, Failed) end. +%% trim/1 +%% +%% Remove any extra bit that was added in diameter_codec to induce a +%% 5014 error. + +trim(#diameter_avp{data = <<0:1, Bin/binary>>} = Avp) -> + Avp#diameter_avp{data = Bin}; + +trim(Avp) -> + Avp. + +%% dict/1 +%% +%% Retrieve the dictionary for the best-effort decode of Failed-AVP, +%% as put by diameter_codec:decode/2. See that function for the +%% explanation. + +dict(true) -> + case get({diameter_codec, dictionary}) of + undefined -> + ?MODULE; + Mod -> + Mod + end; + +dict(_) -> + ?MODULE. + +%% d/5 + +%% Ignore a decode error within Failed-AVP ... +d(true, _, Name, Avp, Acc) -> + decode_AVP(Name, Avp, Acc); + +%% ... or not. Failures here won't be visible since they're a "normal" +%% occurrence if the peer sends a faulty AVP that we need to respond +%% sensibly to. Log the occurence for traceability, but the peer will +%% also receive info in the resulting answer message. +d(false, Reason, Name, Avp, {Avps, Acc}) -> + Stack = diameter_lib:get_stacktrace(), + diameter_lib:log(decode_error, + ?MODULE, + ?LINE, + {Reason, Name, Avp#diameter_avp.name, Stack}), + {Rec, Failed} = Acc, + {[Avp|Avps], {Rec, [rc(Reason, Avp) | Failed]}}. + +%% relax/2 + %% 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 -> + case getr(?STRICT_KEY) of + undefined when 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). +%% relax/1 +%% +%% Set true in the process dictionary as soon as we see Failed-AVP. +%% Matching on 'Failed-AVP' assumes that this is the RFC AVP. +%% Strictly, this doesn't need to be the case. + +relax('Failed-AVP') -> + is_failed() orelse putr(?FAILED_KEY, true); + +relax(_) -> + is_failed(). + +is_failed() -> + true == getr(?FAILED_KEY). + +%% reset/2 + +reset(Key, undefined) -> + eraser(Key); +reset(_, _) -> + ok. + %% decode_AVP/3 %% %% Don't know this AVP: see if it can be packed in an 'AVP' field @@ -410,8 +475,25 @@ pack_avp(_, Arity, Avp, Acc) -> %% pack_AVP/3 -pack_AVP(Name, #diameter_avp{is_mandatory = M} = Avp, Acc) -> - case pack_arity(Name, M) of +%% Length failure was induced because of a header/payload length +%% mismatch. The AVP Length is reset to match the received data if +%% this AVP is encoded in an answer message, since the length is +%% computed. +%% +%% Data is a truncated header if command_code = undefined, otherwise +%% payload bytes. The former is padded to the length of a header if +%% the AVP reaches an outgoing encode in diameter_codec. +%% +%% RFC 6733 says that an AVP returned with 5014 can contain a minimal +%% payload for the AVP's type, but in this case we don't know the +%% type. + +pack_AVP(_, #diameter_avp{data = <<0:1, Data/binary>>} = Avp, Acc) -> + {Rec, Failed} = Acc, + {Rec, [{5014, Avp#diameter_avp{data = Data}} | Failed]}; + +pack_AVP(Name, #diameter_avp{is_mandatory = M, name = AvpName} = Avp, Acc) -> + case pack_arity(Name, AvpName, M) of 0 -> {Rec, Failed} = Acc, {Rec, [{if M -> 5001; true -> 5008 end, Avp} | Failed]}; @@ -419,15 +501,32 @@ 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. +%% Give Failed-AVP special treatment since (1) it'll contain any +%% unrecognized mandatory AVP's and (2) the RFC 3588 grammar failed to +%% allow for Failed-AVP in an answer-message. + +pack_arity(Name, AvpName, M) -> + IsFailed = Name == 'Failed-AVP' orelse is_failed(), + + %% Not testing just Name /= 'Failed-AVP' means we're changing the + %% packing of AVPs nested within Failed-AVP, but the point of + %% ignoring errors within Failed-AVP is to decode as much as + %% possible, and failing because a mandatory AVP couldn't be + %% packed into a dedicated field defeats that point. Note that we + %% can't just test not is_failed() since this will be 'true' when + %% packing an unknown AVP directly within Failed-AVP. + + pack_arity(IsFailed + orelse {Name, AvpName} == {'answer-message', 'Failed-AVP'} + orelse not M + orelse not is_strict(), + Name). + +pack_arity(true, Name) -> + avp_arity(Name, 'AVP'); + +pack_arity(false, _) -> + 0. %% 3588: %% |