diff options
Diffstat (limited to 'lib/diameter/src/base/diameter_codec.erl')
| -rw-r--r-- | lib/diameter/src/base/diameter_codec.erl | 175 |
1 files changed, 138 insertions, 37 deletions
diff --git a/lib/diameter/src/base/diameter_codec.erl b/lib/diameter/src/base/diameter_codec.erl index 09b99b2cae..6c0e73de36 100644 --- a/lib/diameter/src/base/diameter_codec.erl +++ b/lib/diameter/src/base/diameter_codec.erl @@ -38,6 +38,10 @@ -define(MASK(N,I), ((I) band (1 bsl (N)))). +-type u32() :: 0..16#FFFFFFFF. +-type u24() :: 0..16#FFFFFF. +-type u1() :: 0..1. + %% 0 1 2 3 %% 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 %% +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ @@ -55,9 +59,13 @@ %% +-+-+-+-+-+-+-+-+-+-+-+-+- %%% --------------------------------------------------------------------------- -%%% # encode/[2-4] +%%% # encode/2 %%% --------------------------------------------------------------------------- +-spec encode(module(), Msg :: term()) + -> #diameter_packet{} + | no_return(). + encode(Mod, #diameter_packet{} = Pkt) -> try e(Mod, Pkt) @@ -217,6 +225,9 @@ rec2msg(Mod, Rec) -> %% Unsuccessfully decoded AVPs will be placed in #diameter_packet.errors. +-spec decode(module(), #diameter_packet{} | bitstring()) + -> #diameter_packet{}. + decode(Mod, Pkt) -> decode(Mod:id(), Mod, Pkt). @@ -225,9 +236,9 @@ decode(Mod, Pkt) -> %% question. decode(?APP_ID_RELAY, _, #diameter_packet{} = Pkt) -> case collect_avps(Pkt) of - {Bs, As} -> + {E, As} -> Pkt#diameter_packet{avps = As, - errors = [Bs]}; + errors = [E]}; As -> Pkt#diameter_packet{avps = As} end; @@ -251,12 +262,12 @@ decode(Id, Mod, Bin) when is_bitstring(Bin) -> decode(Id, Mod, #diameter_packet{header = decode_header(Bin), bin = Bin}). -decode_avps(MsgName, Mod, Pkt, {Bs, Avps}) -> %% invalid avp bits ... +decode_avps(MsgName, Mod, Pkt, {E, Avps}) -> ?LOG(invalid, Pkt#diameter_packet.bin), #diameter_packet{errors = Failed} = P = decode_avps(MsgName, Mod, Pkt, Avps), - P#diameter_packet{errors = [Bs | Failed]}; + P#diameter_packet{errors = [E | Failed]}; decode_avps('', Mod, Pkt, Avps) -> %% unknown message ... ?LOG(unknown, {Mod, Pkt#diameter_packet.header}), @@ -275,6 +286,10 @@ decode_avps(MsgName, Mod, Pkt, Avps) -> %% ... or not %%% # decode_header/1 %%% --------------------------------------------------------------------------- +-spec decode_header(bitstring()) + -> #diameter_header{} + | false. + decode_header(<<Version:8, MsgLength:24, CmdFlags:1/binary, @@ -324,6 +339,13 @@ decode_header(_) -> %% wraparound counter. The 8-bit counter is incremented each time the %% system is restarted. +-spec sequence_numbers(#diameter_packet{} + | #diameter_header{} + | binary() + | Seq) + -> Seq + when Seq :: {HopByHopId :: u32(), EndToEndId :: u32()}. + sequence_numbers({_,_} = T) -> T; @@ -345,6 +367,9 @@ sequence_numbers(<<_:12/binary, H:32, E:32, _/binary>>) -> %%% # hop_by_hop_id/2 %%% --------------------------------------------------------------------------- +-spec hop_by_hop_id(u32(), binary()) + -> binary(). + hop_by_hop_id(Id, <<H:12/binary, _:32, T/binary>>) -> <<H/binary, Id:32, T/binary>>. @@ -352,6 +377,10 @@ hop_by_hop_id(Id, <<H:12/binary, _:32, T/binary>>) -> %%% # msg_name/2 %%% --------------------------------------------------------------------------- +-spec msg_name(module(), #diameter_header{}) + -> atom() + | {ApplicationId :: u32(), CommandCode :: u24(), Rbit :: u1()}. + msg_name(Dict0, #diameter_header{application_id = ?APP_ID_COMMON, cmd_code = C, is_request = R}) -> @@ -367,6 +396,9 @@ msg_name(_, Hdr) -> %%% # msg_id/1 %%% --------------------------------------------------------------------------- +-spec msg_id(#diameter_packet{} | #diameter_header{}) + -> {ApplicationId :: u32(), CommandCode :: u24(), Rbit :: u1()}. + msg_id(#diameter_packet{msg = [#diameter_header{} = Hdr | _]}) -> msg_id(Hdr); @@ -389,6 +421,12 @@ msg_id(<<_:32, Rbit:1, _:7, CmdCode:24, ApplId:32, _/bitstring>>) -> %% order in the binary. Note also that grouped avp's aren't unraveled, %% only those at the top level. +-spec collect_avps(#diameter_packet{} | bitstring()) + -> [Avp] + | {Error, [Avp]} + when Avp :: #diameter_avp{}, + Error :: {5014, #diameter_avp{}}. + collect_avps(#diameter_packet{bin = Bin}) -> <<_:20/binary, Avps/bitstring>> = Bin, collect_avps(Avps); @@ -403,8 +441,8 @@ collect_avps(Bin, N, Acc) -> {Rest, AVP} -> collect_avps(Rest, N+1, [AVP#diameter_avp{index = N} | Acc]) catch - ?FAILURE(_) -> - {Bin, Acc} + ?FAILURE(Error) -> + {Error, Acc} end. %% 0 1 2 3 @@ -422,44 +460,87 @@ collect_avps(Bin, N, Acc) -> %% split_avp/1 split_avp(Bin) -> - 8 =< size(Bin) orelse ?THROW(truncated_header), + {Code, V, M, P, Len, HdrLen} = split_head(Bin), + {Data, B} = split_data(Bin, HdrLen, Len - HdrLen), + + {B, #diameter_avp{code = Code, + vendor_id = V, + is_mandatory = 1 == M, + need_encryption = 1 == P, + data = Data}}. + +%% split_head/1 + +split_head(<<Code:32, 1:1, M:1, P:1, _:5, Len:24, V:32, _/bitstring>>) -> + {Code, V, M, P, Len, 12}; + +split_head(<<Code:32, 0:1, M:1, P:1, _:5, Len:24, _/bitstring>>) -> + {Code, undefined, M, P, Len, 8}; - <<Code:32, Flags:1/binary, Length:24, Rest/bitstring>> - = Bin, +split_head(Bin) -> + ?THROW({5014, #diameter_avp{data = Bin}}). - 8 =< Length orelse ?THROW(invalid_avp_length), +%% 3588: +%% +%% DIAMETER_INVALID_AVP_LENGTH 5014 +%% The request contained an AVP with an invalid length. A Diameter +%% message indicating this error MUST include the offending AVPs +%% within a Failed-AVP AVP. - DataSize = Length - 8, % size(Code+Flags+Length) = 8 octets - PadSize = (4 - (DataSize rem 4)) rem 4, +%% 6733: +%% +%% DIAMETER_INVALID_AVP_LENGTH 5014 +%% +%% The request contained an AVP with an invalid length. A Diameter +%% message indicating this error MUST include the offending AVPs +%% within a Failed-AVP AVP. In cases where the erroneous AVP length +%% value exceeds the message length or is less than the minimum AVP +%% ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +%% header length, it is sufficient to include the offending AVP +%% ^^^^^^^^^^^^^ +%% header and a zero filled payload of the minimum required length +%% for the payloads data type. If the AVP is a Grouped AVP, the +%% Grouped AVP header with an empty payload would be sufficient to +%% indicate the offending AVP. In the case where the offending AVP +%% header cannot be fully decoded when the AVP length is less than +%% the minimum AVP header length, it is sufficient to include an +%% offending AVP header that is formulated by padding the incomplete +%% AVP header with zero up to the minimum AVP header length. +%% +%% The underlined clause must be in error since (1) a header less than +%% the minimum value mean we don't know the identity of the AVP and +%% (2) the last sentence covers this case. - DataSize + PadSize =< size(Rest) - orelse ?THROW(truncated_data), +%% split_data/3 - <<Data:DataSize/binary, _:PadSize/binary, R/bitstring>> - = Rest, - <<Vbit:1, Mbit:1, Pbit:1, _Reserved:5>> - = Flags, +split_data(Bin, HdrLen, Len) + when 0 =< Len -> + split_data(Bin, HdrLen, Len, (4 - (Len rem 4)) rem 4); - 0 == Vbit orelse 4 =< size(Data) - orelse ?THROW(truncated_vendor_id), +split_data(_, _, _) -> + invalid_avp_length(). - {Vid, D} = vid(Vbit, Data), - {R, #diameter_avp{code = Code, - vendor_id = Vid, - is_mandatory = 1 == Mbit, - need_encryption = 1 == Pbit, - data = D}}. +%% split_data/4 -%% The RFC is a little misleading when stating that OctetString is -%% padded to a 32-bit boundary while other types align naturally. All -%% other types are already multiples of 32 bits so there's no need to -%% distinguish between types here. Any invalid lengths will result in -%% decode error in diameter_types. +split_data(Bin, HdrLen, Len, Pad) -> + <<_:HdrLen/binary, T/bitstring>> = Bin, + case T of + <<Data:Len/binary, _:Pad/binary, Rest/bitstring>> -> + {Data, Rest}; + _ -> + invalid_avp_length() + end. + +%% invalid_avp_length/0 +%% +%% AVP Length doesn't mesh with payload. Induce a decode error by +%% returning a payload that no valid Diameter type can have. This is +%% so that a known AVP will result in 5014 error with a zero'd +%% payload. Here we simply don't know how to construct this payload. +%% (Yes, this solution is an afterthought.) -vid(1, <<Vid:32, Data/bitstring>>) -> - {Vid, Data}; -vid(0, Data) -> - {undefined, Data}. +invalid_avp_length() -> + {<<0:1>>, <<>>}. %%% --------------------------------------------------------------------------- %%% # pack_avp/1 @@ -474,20 +555,35 @@ vid(0, Data) -> pack_avp(#diameter_avp{data = [#diameter_avp{} | _] = Avps} = A) -> pack_avp(A#diameter_avp{data = encode_avps(Avps)}); -%% ... data as a type/value tuple, possibly with header data, ... +%% ... data as a type/value tuple ... pack_avp(#diameter_avp{data = {Type, Value}} = A) when is_atom(Type) -> pack_avp(A#diameter_avp{data = diameter_types:Type(encode, Value)}); + +%% ... with a header in various forms ... pack_avp(#diameter_avp{data = {{_,_,_} = T, {Type, Value}}}) -> pack_avp(T, iolist_to_binary(diameter_types:Type(encode, Value))); + pack_avp(#diameter_avp{data = {{_,_,_} = T, Bin}}) when is_binary(Bin) -> pack_avp(T, Bin); + pack_avp(#diameter_avp{data = {Dict, Name, Value}} = A) -> {Code, _Flags, Vid} = Hdr = Dict:avp_header(Name), {Name, Type} = Dict:avp_name(Code, Vid), pack_avp(A#diameter_avp{data = {Hdr, {Type, Value}}}); +pack_avp(#diameter_avp{code = undefined, data = Bin}) + when is_binary(Bin) -> + %% Reset the AVP Length of an AVP Header resulting from a 5014 + %% error. The RFC doesn't explicitly say to do this but the + %% receiver can't correctly extract this and following AVP's + %% without a correct length. On the downside, the header doesn't + %% reveal if the received header has been padded. + Pad = 8*header_length(Bin) - bit_size(Bin), + Len = size(<<H:5/binary, _:24, T/binary>> = <<Bin/bitstring, 0:Pad>>), + <<H/binary, Len:24, T/binary>>; + %% ... or as an iolist. pack_avp(#diameter_avp{code = Code, vendor_id = V, @@ -499,6 +595,11 @@ pack_avp(#diameter_avp{code = Code, {P, 2#00100000}]), pack_avp({Code, Flags, V}, iolist_to_binary(Data)). +header_length(<<_:32, 1:1, _/bitstring>>) -> + 12; +header_length(_) -> + 8. + flag_avp({true, B}, F) -> F bor B; flag_avp({false, _}, F) -> |