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Diffstat (limited to 'lib/diameter/src/base/diameter_traffic.erl')
| -rw-r--r-- | lib/diameter/src/base/diameter_traffic.erl | 1634 |
1 files changed, 1634 insertions, 0 deletions
diff --git a/lib/diameter/src/base/diameter_traffic.erl b/lib/diameter/src/base/diameter_traffic.erl new file mode 100644 index 0000000000..c8c508fd3b --- /dev/null +++ b/lib/diameter/src/base/diameter_traffic.erl @@ -0,0 +1,1634 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 2013. 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% +%% + +%% +%% Implements the handling of incoming and outgoing Diameter messages +%% except CER/CEA, DWR/DWA and DPR/DPA. That is, the messages that a +%% diameter client sends of receives. +%% + +-module(diameter_traffic). + +%% towards diameter +-export([send_request/4]). + +%% towards diameter_watchdog +-export([receive_message/4]). + +%% towards diameter_service +-export([make_recvdata/1, + peer_up/1, + peer_down/1, + failover/1, + pending/1]). + +%% Other callbacks. +-export([send/1]). %% send from remote node + +-include_lib("diameter/include/diameter.hrl"). +-include("diameter_internal.hrl"). + +-define(RELAY, ?DIAMETER_DICT_RELAY). +-define(BASE, ?DIAMETER_DICT_COMMON). %% Note: the RFC 3588 dictionary + +-define(DEFAULT_TIMEOUT, 5000). %% for outgoing requests + +%% Table containing outgoing requests for which a reply has yet to be +%% received. +-define(REQUEST_TABLE, diameter_request). + +%% Workaround for dialyzer's lack of understanding of match specs. +-type match(T) + :: T | '_' | '$1' | '$2' | '$3' | '$4'. + +%% Record diameter:call/4 options are parsed into. +-record(options, + {filter = none :: diameter:peer_filter(), + extra = [] :: list(), + timeout = ?DEFAULT_TIMEOUT :: 0..16#FFFFFFFF, + detach = false :: boolean()}). + +%% Term passed back to receive_message/4 with every incoming message. +-record(recvdata, + {peerT :: ets:tid(), + service_name :: diameter:service_name(), + apps :: [#diameter_app{}], + sequence :: diameter:sequence()}). + +%% Record stored in diameter_request for each outgoing request. +-record(request, + {ref :: match(reference()), %% used to receive answer + caller :: match(pid()), %% calling process + handler :: match(pid()), %% request process + transport :: match(pid()), %% peer process + caps :: match(#diameter_caps{}), %% of connection + packet :: match(#diameter_packet{})}). %% of request + +%% --------------------------------------------------------------------------- +%% # make_recvdata/1 +%% --------------------------------------------------------------------------- + +make_recvdata([SvcName, PeerT, Apps, Mask | _]) -> + #recvdata{service_name = SvcName, + peerT = PeerT, + apps = Apps, + sequence = Mask}. +%% Take a list so that the caller (diameter_service) can be upgraded +%% first if new members are added. Note that receive_message/4 might +%% still get an old term from any watchdog started in old code. + +%% --------------------------------------------------------------------------- +%% peer_up/1 +%% --------------------------------------------------------------------------- + +%% Insert an element that is used to detect whether or not there has +%% been a failover when inserting an outgoing request. +peer_up(TPid) -> + ets:insert(?REQUEST_TABLE, {TPid}). + +%% --------------------------------------------------------------------------- +%% peer_down/1 +%% --------------------------------------------------------------------------- + +peer_down(TPid) -> + ets:delete(?REQUEST_TABLE, TPid), + failover(TPid). + +%% --------------------------------------------------------------------------- +%% pending/1 +%% --------------------------------------------------------------------------- + +pending(TPids) -> + MatchSpec = [{{'$1', + #request{caller = '$2', + handler = '$3', + transport = '$4', + _ = '_'}, + '_'}, + [?ORCOND([{'==', T, '$4'} || T <- TPids])], + [{{'$1', [{{caller, '$2'}}, + {{handler, '$3'}}, + {{transport, '$4'}}]}}]}], + + try + ets:select(?REQUEST_TABLE, MatchSpec) + catch + error: badarg -> [] %% service has gone down + end. + +%% --------------------------------------------------------------------------- +%% # receive_message/4 +%% +%% Handle an incoming Diameter message. +%% --------------------------------------------------------------------------- + +%% Handle an incoming Diameter message in the watchdog process. This +%% used to come through the service process but this avoids that +%% becoming a bottleneck. + +receive_message(TPid, Pkt, Dict0, RecvData) + when is_pid(TPid) -> + #diameter_packet{header = #diameter_header{is_request = R}} = Pkt, + recv(R, + (not R) andalso lookup_request(Pkt, TPid), + TPid, + Pkt, + Dict0, + RecvData). + +%% Incoming request ... +recv(true, false, TPid, Pkt, Dict0, RecvData) -> + try + spawn(fun() -> recv_request(TPid, Pkt, Dict0, RecvData) end) + catch + error: system_limit = E -> %% discard + ?LOG({error, E}, now()) + end; + +%% ... answer to known request ... +recv(false, #request{ref = Ref, handler = Pid} = Req, _, Pkt, Dict0, _) -> + Pid ! {answer, Ref, Req, Dict0, Pkt}; +%% Note that failover could have happened prior to this message being +%% received and triggering failback. That is, both a failover message +%% and answer may be on their way to the handler process. In the worst +%% case the request process gets notification of the failover and +%% sends to the alternate peer before an answer arrives, so it's +%% always the case that we can receive more than one answer after +%% failover. The first answer received by the request process wins, +%% any others are discarded. + +%% ... or not. +recv(false, false, _, _, _, _) -> + ok. + +%% --------------------------------------------------------------------------- +%% recv_request/4 +%% --------------------------------------------------------------------------- + +recv_request(TPid, + #diameter_packet{header = #diameter_header{application_id = Id}} + = Pkt, + Dict0, + #recvdata{peerT = PeerT, apps = Apps} + = RecvData) -> + recv_request(diameter_service:find_incoming_app(PeerT, TPid, Id, Apps), + TPid, + Pkt, + Dict0, + RecvData). + +%% recv_request/5 + +recv_request({#diameter_app{id = Id, dictionary = Dict} = App, Caps}, + TPid, + Pkt, + Dict0, + RecvData) -> + recv_R(App, + TPid, + Caps, + Dict0, + RecvData, + diameter_codec:decode(Id, Dict, Pkt)); +%% Note that the decode is different depending on whether or not Id is +%% ?APP_ID_RELAY. + +%% DIAMETER_APPLICATION_UNSUPPORTED 3007 +%% A request was sent for an application that is not supported. + +recv_request(#diameter_caps{} = Caps, TPid, Pkt, Dict0, _) -> + As = collect_avps(Pkt), + protocol_error(3007, TPid, Caps, Dict0, Pkt#diameter_packet{avps = As}); + +recv_request(false, _, _, _, _) -> %% transport has gone down + ok. + +collect_avps(Pkt) -> + case diameter_codec:collect_avps(Pkt) of + {_Bs, As} -> + As; + As -> + As + end. + +%% recv_R/6 + +%% Wrong number of bits somewhere in the message: reply. +%% +%% DIAMETER_INVALID_AVP_BITS 3009 +%% A request was received that included an AVP whose flag bits are +%% set to an unrecognized value, or that is inconsistent with the +%% AVP's definition. +%% +recv_R(_App, + TPid, + Caps, + Dict0, + _RecvData, + #diameter_packet{errors = [Bs | _]} = Pkt) + when is_bitstring(Bs) -> + protocol_error(3009, TPid, Caps, Dict0, Pkt); + +%% Either we support this application but don't recognize the command +%% or we're a relay and the command isn't proxiable. +%% +%% DIAMETER_COMMAND_UNSUPPORTED 3001 +%% The Request contained a Command-Code that the receiver did not +%% recognize or support. This MUST be used when a Diameter node +%% receives an experimental command that it does not understand. +%% +recv_R(#diameter_app{id = Id}, + TPid, + Caps, + Dict0, + _RecvData, + #diameter_packet{header = #diameter_header{is_proxiable = P}, + msg = M} + = Pkt) + when ?APP_ID_RELAY /= Id, undefined == M; + ?APP_ID_RELAY == Id, not P -> + protocol_error(3001, TPid, Caps, Dict0, Pkt); + +%% Error bit was set on a request. +%% +%% DIAMETER_INVALID_HDR_BITS 3008 +%% A request was received whose bits in the Diameter header were +%% either set to an invalid combination, or to a value that is +%% inconsistent with the command code's definition. +%% +recv_R(_App, + TPid, + Caps, + Dict0, + _RecvData, + #diameter_packet{header = #diameter_header{is_error = true}} + = Pkt) -> + protocol_error(3008, TPid, Caps, Dict0, Pkt); + +%% A message in a locally supported application or a proxiable message +%% in the relay application. Don't distinguish between the two since +%% each application has its own callback config. That is, the user can +%% easily distinguish between the two cases. +recv_R(App, TPid, Caps, Dict0, RecvData, Pkt) -> + request_cb(App, TPid, Caps, Dict0, RecvData, examine(Pkt)). + +%% Note that there may still be errors but these aren't protocol +%% (3xxx) errors that lead to an answer-message. + +request_cb(App, + TPid, + Caps, + Dict0, + #recvdata{service_name = SvcName} + = RecvData, + Pkt) -> + request_cb(cb(App, handle_request, [Pkt, SvcName, {TPid, Caps}]), + App, + TPid, + Caps, + Dict0, + RecvData, + [], + Pkt). + +%% examine/1 +%% +%% Look for errors in a decoded message. Length errors result in +%% decode failure in diameter_codec. + +examine(#diameter_packet{header = #diameter_header{version + = ?DIAMETER_VERSION}} + = Pkt) -> + Pkt; + +%% DIAMETER_UNSUPPORTED_VERSION 5011 +%% This error is returned when a request was received, whose version +%% number is unsupported. + +examine(#diameter_packet{errors = Es} = Pkt) -> + Pkt#diameter_packet{errors = [5011 | Es]}. +%% It's odd/unfortunate that this isn't a protocol error. + +%% request_cb/8 + +%% A reply may be an answer-message, constructed either here or by +%% the handle_request callback. The header from the incoming request +%% is passed into the encode so that it can retrieve the relevant +%% command code in this case. It will also then ignore Dict and use +%% the base encoder. +request_cb({reply, Ans}, + #diameter_app{dictionary = Dict}, + TPid, + _Caps, + Dict0, + _RecvData, + Fs, + Pkt) -> + reply(Ans, dict(Dict, Dict0, Ans), TPid, Fs, Pkt); + +%% An 3xxx result code, for which the E-bit is set in the header. +request_cb({protocol_error, RC}, + _App, + TPid, + Caps, + Dict0, + _RecvData, + Fs, + Pkt) + when 3000 =< RC, RC < 4000 -> + protocol_error(RC, TPid, Caps, Dict0, Fs, Pkt); + +%% RFC 3588 says we must reply 3001 to anything unrecognized or +%% unsupported. 'noreply' is undocumented (and inappropriately named) +%% backwards compatibility for this, protocol_error the documented +%% alternative. +request_cb(noreply, + _App, + TPid, + Caps, + Dict0, + _RecvData, + Fs, + Pkt) -> + protocol_error(3001, TPid, Caps, Dict0, Fs, Pkt); + +%% Relay a request to another peer. This is equivalent to doing an +%% explicit call/4 with the message in question except that (1) a loop +%% will be detected by examining Route-Record AVP's, (3) a +%% Route-Record AVP will be added to the outgoing request and (3) the +%% End-to-End Identifier will default to that in the +%% #diameter_header{} without the need for an end_to_end_identifier +%% option. +%% +%% relay and proxy are similar in that they require the same handling +%% with respect to Route-Record and End-to-End identifier. The +%% difference is that a proxy advertises specific applications, while +%% a relay advertises the relay application. If a callback doesn't +%% want to distinguish between the cases in the callback return value +%% then 'resend' is a neutral alternative. +%% +request_cb({A, Opts}, + #diameter_app{id = Id} + = App, + TPid, + Caps, + Dict0, + RecvData, + Fs, + Pkt) + when A == relay, Id == ?APP_ID_RELAY; + A == proxy, Id /= ?APP_ID_RELAY; + A == resend -> + resend(Opts, App, TPid, Caps, Dict0, RecvData, Fs, Pkt); + +request_cb(discard, _, _, _, _, _, _, _) -> + ok; + +request_cb({eval_packet, RC, F}, App, TPid, Caps, Dict0, RecvData, Fs, Pkt) -> + request_cb(RC, App, TPid, Caps, Dict0, RecvData, [F|Fs], Pkt); + +request_cb({eval, RC, F}, App, TPid, Caps, Dict0, RecvData, Fs, Pkt) -> + request_cb(RC, App, TPid, Caps, Dict0, RecvData, Fs, Pkt), + diameter_lib:eval(F). + +%% dict/3 + +%% An incoming answer, not yet decoded. +dict(Dict, Dict0, #diameter_packet{header + = #diameter_header{is_request = false, + is_error = E}, + msg = undefined}) -> + if E -> Dict0; true -> Dict end; + +dict(Dict, Dict0, [Msg]) -> + dict(Dict, Dict0, Msg); + +dict(Dict, Dict0, #diameter_packet{msg = Msg}) -> + dict(Dict, Dict0, Msg); + +dict(_Dict, Dict0, ['answer-message' | _]) -> + Dict0; + +dict(Dict, Dict0, Rec) -> + try + 'answer-message' = Dict0:rec2msg(element(1,Rec)), + Dict0 + catch + error:_ -> Dict + end. + +%% protocol_error/6 + +protocol_error(RC, TPid, Caps, Dict0, Fs, Pkt) -> + #diameter_caps{origin_host = {OH,_}, + origin_realm = {OR,_}} + = Caps, + #diameter_packet{avps = Avps, errors = Es} + = Pkt, + + ?LOG({error, RC}, Pkt), + reply(answer_message({OH, OR, RC}, Dict0, Avps), + Dict0, + TPid, + Fs, + Pkt#diameter_packet{errors = [RC | Es]}). +%% Note that reply/5 may set the result code once more. It's set in +%% answer_message/3 in case reply/5 doesn't. + +%% protocol_error/5 + +protocol_error(RC, TPid, Caps, Dict0, Pkt) -> + protocol_error(RC, TPid, Caps, Dict0, [], Pkt). + +%% resend/7 +%% +%% Resend a message as a relay or proxy agent. + +resend(Opts, + #diameter_app{} + = App, + TPid, + #diameter_caps{origin_host = {OH,_}} + = Caps, + Dict0, + RecvData, + Fs, + #diameter_packet{avps = Avps} + = Pkt) -> + {Code, _Flags, Vid} = Dict0:avp_header('Route-Record'), + resend(is_loop(Code, Vid, OH, Dict0, Avps), + Opts, + App, + TPid, + Caps, + Dict0, + RecvData, + Fs, + Pkt). + +%% DIAMETER_LOOP_DETECTED 3005 +%% An agent detected a loop while trying to get the message to the +%% intended recipient. The message MAY be sent to an alternate peer, +%% if one is available, but the peer reporting the error has +%% identified a configuration problem. + +resend(true, _Opts, _App, TPid, Caps, Dict0, _RecvData, Fs, Pkt) -> + protocol_error(3005, TPid, Caps, Dict0, Fs, Pkt); + +%% 6.1.8. Relaying and Proxying Requests +%% +%% A relay or proxy agent MUST append a Route-Record AVP to all requests +%% forwarded. The AVP contains the identity of the peer the request was +%% received from. + +resend(false, + Opts, + App, + TPid, + #diameter_caps{origin_host = {_,OH}} + = Caps, + Dict0, + #recvdata{service_name = SvcName, + sequence = Mask}, + Fs, + #diameter_packet{header = Hdr0, + avps = Avps} + = Pkt) -> + Route = #diameter_avp{data = {Dict0, 'Route-Record', OH}}, + Seq = diameter_session:sequence(Mask), + Hdr = Hdr0#diameter_header{hop_by_hop_id = Seq}, + Msg = [Hdr, Route | Avps], + resend(send_request(SvcName, App, Msg, Opts), TPid, Caps, Dict0, Fs, Pkt). +%% The incoming request is relayed with the addition of a +%% Route-Record. Note the requirement on the return from call/4 below, +%% which places a requirement on the value returned by the +%% handle_answer callback of the application module in question. +%% +%% Note that there's nothing stopping the request from being relayed +%% back to the sender. A pick_peer callback may want to avoid this but +%% a smart peer might recognize the potential loop and choose another +%% route. A less smart one will probably just relay the request back +%% again and force us to detect the loop. A pick_peer that wants to +%% avoid this can specify filter to avoid the possibility. +%% Eg. {neg, {host, OH} where #diameter_caps{origin_host = {OH, _}}. +%% +%% RFC 6.3 says that a relay agent does not modify Origin-Host but +%% says nothing about a proxy. Assume it should behave the same way. + +%% resend/6 +%% +%% Relay a reply to a relayed request. + +%% Answer from the peer: reset the hop by hop identifier and send. +resend(#diameter_packet{bin = B} + = Pkt, + TPid, + _Caps, + _Dict0, + Fs, + #diameter_packet{header = #diameter_header{hop_by_hop_id = Id}, + transport_data = TD}) -> + P = Pkt#diameter_packet{bin = diameter_codec:hop_by_hop_id(Id, B), + transport_data = TD}, + eval_packet(P, Fs), + send(TPid, P); +%% TODO: counters + +%% Or not: DIAMETER_UNABLE_TO_DELIVER. +resend(_, TPid, Caps, Dict0, Fs, Pkt) -> + protocol_error(3002, TPid, Caps, Dict0, Fs, Pkt). + +%% is_loop/5 +%% +%% Is there a Route-Record AVP with our Origin-Host? + +is_loop(Code, + Vid, + Bin, + _Dict0, + [#diameter_avp{code = Code, vendor_id = Vid, data = Bin} | _]) -> + true; + +is_loop(_, _, _, _, []) -> + false; + +is_loop(Code, Vid, OH, Dict0, [_ | Avps]) + when is_binary(OH) -> + is_loop(Code, Vid, OH, Dict0, Avps); + +is_loop(Code, Vid, OH, Dict0, Avps) -> + is_loop(Code, Vid, Dict0:avp(encode, OH, 'Route-Record'), Dict0, Avps). + +%% reply/5 +%% +%% Send a locally originating reply. + +%% Skip the setting of Result-Code and Failed-AVP's below. This is +%% currently undocumented. +reply([Msg], Dict, TPid, Fs, Pkt) + when is_list(Msg); + is_tuple(Msg) -> + reply(Msg, Dict, TPid, Fs, Pkt#diameter_packet{errors = []}); + +%% No errors or a diameter_header/avp list. +reply(Msg, Dict, TPid, Fs, #diameter_packet{errors = Es} = ReqPkt) + when [] == Es; + is_record(hd(Msg), diameter_header) -> + Pkt = encode(Dict, make_answer_packet(Msg, ReqPkt), Fs), + incr(send, Pkt, Dict, TPid), %% count result codes in sent answers + send(TPid, Pkt); + +%% Or not: set Result-Code and Failed-AVP AVP's. +reply(Msg, Dict, TPid, Fs, #diameter_packet{errors = [H|_] = Es} = Pkt) -> + reply(rc(Msg, rc(H), [A || {_,A} <- Es], Dict), + Dict, + TPid, + Fs, + Pkt#diameter_packet{errors = []}). + +eval_packet(Pkt, Fs) -> + lists:foreach(fun(F) -> diameter_lib:eval([F,Pkt]) end, Fs). + +%% make_answer_packet/2 + +%% A reply message clears the R and T flags and retains the P flag. +%% The E flag will be set at encode. 6.2 of 3588 requires the same P +%% flag on an answer as on the request. A #diameter_packet{} returned +%% from a handle_request callback can circumvent this by setting its +%% own header values. +make_answer_packet(#diameter_packet{header = Hdr, + msg = Msg, + transport_data = TD}, + #diameter_packet{header = ReqHdr}) -> + Hdr0 = ReqHdr#diameter_header{version = ?DIAMETER_VERSION, + is_request = false, + is_error = undefined, + is_retransmitted = false}, + #diameter_packet{header = fold_record(Hdr0, Hdr), + msg = Msg, + transport_data = TD}; + +%% Binaries and header/avp lists are sent as-is. +make_answer_packet(Bin, #diameter_packet{transport_data = TD}) + when is_binary(Bin) -> + #diameter_packet{bin = Bin, + transport_data = TD}; +make_answer_packet([#diameter_header{} | _] = Msg, + #diameter_packet{transport_data = TD}) -> + #diameter_packet{msg = Msg, + transport_data = TD}; + +%% Otherwise, preserve transport_data. +make_answer_packet(Msg, #diameter_packet{transport_data = TD} = Pkt) -> + make_answer_packet(#diameter_packet{msg = Msg, transport_data = TD}, Pkt). + +%% rc/1 + +rc({RC, _}) -> + RC; +rc(RC) -> + RC. + +%% rc/4 + +rc(#diameter_packet{msg = Rec} = Pkt, RC, Failed, DictT) -> + Pkt#diameter_packet{msg = rc(Rec, RC, Failed, DictT)}; + +rc(Rec, RC, Failed, DictT) + when is_integer(RC) -> + set(Rec, + lists:append([rc(Rec, {'Result-Code', RC}, DictT), + failed_avp(Rec, Failed, DictT)]), + DictT). + +%% Reply as name and tuple list ... +set([_|_] = Ans, Avps, _) -> + Ans ++ Avps; %% Values nearer tail take precedence. + +%% ... or record. +set(Rec, Avps, Dict) -> + Dict:'#set-'(Avps, Rec). + +%% rc/3 +%% +%% Turn the result code into a list if its optional and only set it if +%% the arity is 1 or {0,1}. In other cases (which probably shouldn't +%% exist in practise) we can't know what's appropriate. + +rc([MsgName | _], {'Result-Code' = K, RC} = T, Dict) -> + case Dict:avp_arity(MsgName, 'Result-Code') of + 1 -> [T]; + {0,1} -> [{K, [RC]}]; + _ -> [] + end; + +rc(Rec, T, Dict) -> + rc([Dict:rec2msg(element(1, Rec))], T, Dict). + +%% failed_avp/3 + +failed_avp(_, [] = No, _) -> + No; + +failed_avp(Rec, Failed, Dict) -> + [fa(Rec, [{'AVP', Failed}], Dict)]. + +%% Reply as name and tuple list ... +fa([MsgName | Values], FailedAvp, Dict) -> + R = Dict:msg2rec(MsgName), + try + Dict:'#info-'(R, {index, 'Failed-AVP'}), + {'Failed-AVP', [FailedAvp]} + catch + error: _ -> + Avps = proplists:get_value('AVP', Values, []), + A = #diameter_avp{name = 'Failed-AVP', + value = FailedAvp}, + {'AVP', [A|Avps]} + end; + +%% ... or record. +fa(Rec, FailedAvp, Dict) -> + try + {'Failed-AVP', [FailedAvp]} + catch + error: _ -> + Avps = Dict:'get-'('AVP', Rec), + A = #diameter_avp{name = 'Failed-AVP', + value = FailedAvp}, + {'AVP', [A|Avps]} + end. + +%% 3. Diameter Header +%% +%% E(rror) - If set, the message contains a protocol error, +%% and the message will not conform to the ABNF +%% described for this command. Messages with the 'E' +%% bit set are commonly referred to as error +%% messages. This bit MUST NOT be set in request +%% messages. See Section 7.2. + +%% 3.2. Command Code ABNF specification +%% +%% e-bit = ", ERR" +%% ; If present, the 'E' bit in the Command +%% ; Flags is set, indicating that the answer +%% ; message contains a Result-Code AVP in +%% ; the "protocol error" class. + +%% 7.1.3. Protocol Errors +%% +%% Errors that fall within the Protocol Error category SHOULD be treated +%% on a per-hop basis, and Diameter proxies MAY attempt to correct the +%% error, if it is possible. Note that these and only these errors MUST +%% only be used in answer messages whose 'E' bit is set. + +%% Thus, only construct answers to protocol errors. Other errors +%% require an message-specific answer and must be handled by the +%% application. + +%% 6.2. Diameter Answer Processing +%% +%% When a request is locally processed, the following procedures MUST be +%% applied to create the associated answer, in addition to any +%% additional procedures that MAY be discussed in the Diameter +%% application defining the command: +%% +%% - The same Hop-by-Hop identifier in the request is used in the +%% answer. +%% +%% - The local host's identity is encoded in the Origin-Host AVP. +%% +%% - The Destination-Host and Destination-Realm AVPs MUST NOT be +%% present in the answer message. +%% +%% - The Result-Code AVP is added with its value indicating success or +%% failure. +%% +%% - If the Session-Id is present in the request, it MUST be included +%% in the answer. +%% +%% - Any Proxy-Info AVPs in the request MUST be added to the answer +%% message, in the same order they were present in the request. +%% +%% - The 'P' bit is set to the same value as the one in the request. +%% +%% - The same End-to-End identifier in the request is used in the +%% answer. +%% +%% Note that the error messages (see Section 7.3) are also subjected to +%% the above processing rules. + +%% 7.3. Error-Message AVP +%% +%% The Error-Message AVP (AVP Code 281) is of type UTF8String. It MAY +%% accompany a Result-Code AVP as a human readable error message. The +%% Error-Message AVP is not intended to be useful in real-time, and +%% SHOULD NOT be expected to be parsed by network entities. + +%% answer_message/3 + +answer_message({OH, OR, RC}, Dict0, Avps) -> + {Code, _, Vid} = Dict0:avp_header('Session-Id'), + ['answer-message', {'Origin-Host', OH}, + {'Origin-Realm', OR}, + {'Result-Code', RC} + | session_id(Code, Vid, Dict0, Avps)]. + +session_id(Code, Vid, Dict0, Avps) + when is_list(Avps) -> + try + {value, #diameter_avp{data = D}} = find_avp(Code, Vid, Avps), + [{'Session-Id', [Dict0:avp(decode, D, 'Session-Id')]}] + catch + error: _ -> + [] + end. + +%% find_avp/3 + +find_avp(Code, Vid, Avps) + when is_integer(Code), (undefined == Vid orelse is_integer(Vid)) -> + find(fun(A) -> is_avp(Code, Vid, A) end, Avps). + +%% The final argument here could be a list of AVP's, depending on the case, +%% but we're only searching at the top level. +is_avp(Code, Vid, #diameter_avp{code = Code, vendor_id = Vid}) -> + true; +is_avp(_, _, _) -> + false. + +find(_, []) -> + false; +find(Pred, [H|T]) -> + case Pred(H) of + true -> + {value, H}; + false -> + find(Pred, T) + end. + +%% 7. Error Handling +%% +%% There are certain Result-Code AVP application errors that require +%% additional AVPs to be present in the answer. In these cases, the +%% Diameter node that sets the Result-Code AVP to indicate the error +%% MUST add the AVPs. Examples are: +%% +%% - An unrecognized AVP is received with the 'M' bit (Mandatory bit) +%% set, causes an answer to be sent with the Result-Code AVP set to +%% DIAMETER_AVP_UNSUPPORTED, and the Failed-AVP AVP containing the +%% offending AVP. +%% +%% - An AVP that is received with an unrecognized value causes an +%% answer to be returned with the Result-Code AVP set to +%% DIAMETER_INVALID_AVP_VALUE, with the Failed-AVP AVP containing the +%% AVP causing the error. +%% +%% - A command is received with an AVP that is omitted, yet is +%% mandatory according to the command's ABNF. The receiver issues an +%% answer with the Result-Code set to DIAMETER_MISSING_AVP, and +%% creates an AVP with the AVP Code and other fields set as expected +%% in the missing AVP. The created AVP is then added to the Failed- +%% AVP AVP. +%% +%% The Result-Code AVP describes the error that the Diameter node +%% encountered in its processing. In case there are multiple errors, +%% the Diameter node MUST report only the first error it encountered +%% (detected possibly in some implementation dependent order). The +%% specific errors that can be described by this AVP are described in +%% the following section. + +%% 7.5. Failed-AVP AVP +%% +%% The Failed-AVP AVP (AVP Code 279) is of type Grouped and provides +%% debugging information in cases where a request is rejected or not +%% fully processed due to erroneous information in a specific AVP. The +%% value of the Result-Code AVP will provide information on the reason +%% for the Failed-AVP AVP. +%% +%% The possible reasons for this AVP are the presence of an improperly +%% constructed AVP, an unsupported or unrecognized AVP, an invalid AVP +%% value, the omission of a required AVP, the presence of an explicitly +%% excluded AVP (see tables in Section 10), or the presence of two or +%% more occurrences of an AVP which is restricted to 0, 1, or 0-1 +%% occurrences. +%% +%% A Diameter message MAY contain one Failed-AVP AVP, containing the +%% entire AVP that could not be processed successfully. If the failure +%% reason is omission of a required AVP, an AVP with the missing AVP +%% code, the missing vendor id, and a zero filled payload of the minimum +%% required length for the omitted AVP will be added. + +%% incr/4 +%% +%% Increment a stats counter for an incoming or outgoing message. + +%% Outgoing message as binary: don't count. (Sending binaries is only +%% partially supported.) +incr(_, #diameter_packet{msg = undefined}, _, _) -> + ok; + +incr(recv = D, #diameter_packet{header = H, errors = [_|_]}, _, TPid) -> + incr(TPid, {diameter_codec:msg_id(H), D, error}); + +incr(Dir, Pkt, Dict, TPid) -> + #diameter_packet{header = #diameter_header{is_error = E} + = Hdr, + msg = Rec} + = Pkt, + + RC = int(get_avp_value(Dict, 'Result-Code', Rec)), + PE = is_protocol_error(RC), + + %% Check that the E bit is set only for 3xxx result codes. + (not (E orelse PE)) + orelse (E andalso PE) + orelse x({invalid_error_bit, RC}, answer, [Dir, Pkt]), + + irc(TPid, Hdr, Dir, rc_counter(Dict, Rec, RC)). + +irc(_, _, _, undefined) -> + false; + +irc(TPid, Hdr, Dir, Ctr) -> + incr(TPid, {diameter_codec:msg_id(Hdr), Dir, Ctr}). + +%% incr/2 + +incr(TPid, Counter) -> + diameter_stats:incr(Counter, TPid, 1). + +%% error_counter/2 + +%% RFC 3588, 7.6: +%% +%% All Diameter answer messages defined in vendor-specific +%% applications MUST include either one Result-Code AVP or one +%% Experimental-Result AVP. +%% +%% Maintain statistics assuming one or the other, not both, which is +%% surely the intent of the RFC. + +rc_counter(Dict, Rec, undefined) -> + rcc(get_avp_value(Dict, 'Experimental-Result', Rec)); +rc_counter(_, _, RC) -> + {'Result-Code', RC}. + +%% Outgoing answers may be in any of the forms messages can be sent +%% in. Incoming messages will be records. We're assuming here that the +%% arity of the result code AVP's is 0 or 1. + +rcc([{_,_,N} = T | _]) + when is_integer(N) -> + T; +rcc({_,_,N} = T) + when is_integer(N) -> + T; +rcc(_) -> + undefined. + +%% Extract the first good looking integer. There's no guarantee +%% that what we're looking for has arity 1. +int([N|_]) + when is_integer(N) -> + N; +int(N) + when is_integer(N) -> + N; +int(_) -> + undefined. + +is_protocol_error(RC) -> + 3000 =< RC andalso RC < 4000. + +-spec x(any(), atom(), list()) -> no_return(). + +%% Warn and exit request process on errors in an incoming answer. +x(Reason, F, A) -> + diameter_lib:warning_report(Reason, {?MODULE, F, A}), + x(Reason). + +x(T) -> + exit(T). + +%% --------------------------------------------------------------------------- +%% # send_request/4 +%% +%% Handle an outgoing Diameter request. +%% --------------------------------------------------------------------------- + +send_request(SvcName, AppOrAlias, Msg, Options) + when is_list(Options) -> + Rec = make_options(Options), + Ref = make_ref(), + Caller = {self(), Ref}, + ReqF = fun() -> + exit({Ref, send_R(SvcName, AppOrAlias, Msg, Rec, Caller)}) + end, + try spawn_monitor(ReqF) of + {_, MRef} -> + recv_A(MRef, Ref, Rec#options.detach, false) + catch + error: system_limit = E -> + {error, E} + end. +%% The R in send_R is because Diameter request are usually given short +%% names of the form XXR. (eg. CER, DWR, etc.) Similarly, answers have +%% names of the form XXA. + +%% Don't rely on gen_server:call/3 for the timeout handling since it +%% makes no guarantees about not leaving a reply message in the +%% mailbox if we catch its exit at timeout. It currently *can* do so, +%% which is also undocumented. + +recv_A(MRef, _, true, true) -> + erlang:demonitor(MRef, [flush]), + ok; + +recv_A(MRef, Ref, Detach, Sent) -> + receive + Ref -> %% send has been attempted + recv_A(MRef, Ref, Detach, true); + {'DOWN', MRef, process, _, Reason} -> + answer_rc(Reason, Ref, Sent) + end. + +%% send_R/5 has returned ... +answer_rc({Ref, Ans}, Ref, _) -> + Ans; + +%% ... or not. Note that failure/encode are documented return values. +answer_rc(_, _, Sent) -> + {error, choose(Sent, failure, encode)}. + +%% send_R/5 +%% +%% In the process spawned for the outgoing request. + +send_R(SvcName, AppOrAlias, Msg, Opts, Caller) -> + case pick_peer(SvcName, AppOrAlias, Msg, Opts) of + {{_,_,_} = Transport, Mask} -> + send_request(Transport, Mask, Msg, Opts, Caller, SvcName); + false -> + {error, no_connection}; + {error, _} = No -> + No + end. + +%% make_options/1 + +make_options(Options) -> + lists:foldl(fun mo/2, #options{}, Options). + +mo({timeout, T}, Rec) + when is_integer(T), 0 =< T -> + Rec#options{timeout = T}; + +mo({filter, F}, #options{filter = none} = Rec) -> + Rec#options{filter = F}; +mo({filter, F}, #options{filter = {all, Fs}} = Rec) -> + Rec#options{filter = {all, [F | Fs]}}; +mo({filter, F}, #options{filter = F0} = Rec) -> + Rec#options{filter = {all, [F0, F]}}; + +mo({extra, L}, #options{extra = X} = Rec) + when is_list(L) -> + Rec#options{extra = X ++ L}; + +mo(detach, Rec) -> + Rec#options{detach = true}; + +mo(T, _) -> + ?ERROR({invalid_option, T}). + +%% --------------------------------------------------------------------------- +%% # send_request/6 +%% --------------------------------------------------------------------------- + +%% Send an outgoing request in its dedicated process. +%% +%% Note that both encode of the outgoing request and of the received +%% answer happens in this process. It's also this process that replies +%% to the caller. The service process only handles the state-retaining +%% callbacks. +%% +%% The module field of the #diameter_app{} here includes any extra +%% arguments passed to diameter:call/4. + +send_request({TPid, Caps, App} + = Transport, + Mask, + Msg, + Opts, + Caller, + SvcName) -> + Pkt = make_prepare_packet(Mask, Msg), + + send_R(cb(App, prepare_request, [Pkt, SvcName, {TPid, Caps}]), + Pkt, + Transport, + Opts, + Caller, + SvcName, + []). + +send_R({send, Msg}, Pkt, Transport, Opts, Caller, SvcName, Fs) -> + send_R(make_request_packet(Msg, Pkt), + Transport, + Opts, + Caller, + SvcName, + Fs); + +send_R({discard, Reason} , _, _, _, _, _, _) -> + {error, Reason}; + +send_R(discard, _, _, _, _, _, _) -> + {error, discarded}; + +send_R({eval_packet, RC, F}, Pkt, T, Opts, Caller, SvcName, Fs) -> + send_R(RC, Pkt, T, Opts, Caller, SvcName, [F|Fs]); + +send_R(E, _, {_, _, App}, _, _, _, _) -> + ?ERROR({invalid_return, prepare_request, App, E}). + +%% make_prepare_packet/2 +%% +%% Turn an outgoing request as passed to call/4 into a diameter_packet +%% record in preparation for a prepare_request callback. + +make_prepare_packet(_, Bin) + when is_binary(Bin) -> + #diameter_packet{header = diameter_codec:decode_header(Bin), + bin = Bin}; + +make_prepare_packet(Mask, #diameter_packet{msg = [#diameter_header{} = Hdr + | Avps]} + = Pkt) -> + Pkt#diameter_packet{msg = [make_prepare_header(Mask, Hdr) | Avps]}; + +make_prepare_packet(Mask, #diameter_packet{header = Hdr} = Pkt) -> + Pkt#diameter_packet{header = make_prepare_header(Mask, Hdr)}; + +make_prepare_packet(Mask, Msg) -> + make_prepare_packet(Mask, #diameter_packet{msg = Msg}). + +%% make_prepare_header/2 + +make_prepare_header(Mask, undefined) -> + Seq = diameter_session:sequence(Mask), + make_prepare_header(#diameter_header{end_to_end_id = Seq, + hop_by_hop_id = Seq}); + +make_prepare_header(Mask, #diameter_header{end_to_end_id = undefined, + hop_by_hop_id = undefined} + = H) -> + Seq = diameter_session:sequence(Mask), + make_prepare_header(H#diameter_header{end_to_end_id = Seq, + hop_by_hop_id = Seq}); + +make_prepare_header(Mask, #diameter_header{end_to_end_id = undefined} = H) -> + Seq = diameter_session:sequence(Mask), + make_prepare_header(H#diameter_header{end_to_end_id = Seq}); + +make_prepare_header(Mask, #diameter_header{hop_by_hop_id = undefined} = H) -> + Seq = diameter_session:sequence(Mask), + make_prepare_header(H#diameter_header{hop_by_hop_id = Seq}); + +make_prepare_header(_, Hdr) -> + make_prepare_header(Hdr). + +%% make_prepare_header/1 + +make_prepare_header(#diameter_header{version = undefined} = Hdr) -> + make_prepare_header(Hdr#diameter_header{version = ?DIAMETER_VERSION}); + +make_prepare_header(#diameter_header{} = Hdr) -> + Hdr; + +make_prepare_header(T) -> + ?ERROR({invalid_header, T}). + +%% make_request_packet/2 +%% +%% Reconstruct a diameter_packet from the return value of +%% prepare_request or prepare_retransmit callback. + +make_request_packet(Bin, _) + when is_binary(Bin) -> + make_prepare_packet(false, Bin); + +make_request_packet(#diameter_packet{msg = [#diameter_header{} | _]} + = Pkt, + _) -> + Pkt; + +%% Returning a diameter_packet with no header from a prepare_request +%% or prepare_retransmit callback retains the header passed into it. +%% This is primarily so that the end to end and hop by hop identifiers +%% are retained. +make_request_packet(#diameter_packet{header = Hdr} = Pkt, + #diameter_packet{header = Hdr0}) -> + Pkt#diameter_packet{header = fold_record(Hdr0, Hdr)}; + +make_request_packet(Msg, Pkt) -> + Pkt#diameter_packet{msg = Msg}. + +%% fold_record/2 + +fold_record(undefined, R) -> + R; +fold_record(Rec, R) -> + diameter_lib:fold_tuple(2, Rec, R). + +%% send_R/6 + +send_R(Pkt0, + {TPid, Caps, #diameter_app{dictionary = Dict} = App}, + Opts, + {Pid, Ref}, + SvcName, + Fs) -> + Pkt = encode(Dict, Pkt0, Fs), + + #options{timeout = Timeout} + = Opts, + + Req = #request{ref = Ref, + caller = Pid, + handler = self(), + transport = TPid, + caps = Caps, + packet = Pkt0}, + + try + TRef = send_request(TPid, Pkt, Req, SvcName, Timeout), + Pid ! Ref, %% tell caller a send has been attempted + handle_answer(SvcName, + App, + recv_A(Timeout, SvcName, App, Opts, {TRef, Req})) + after + erase_requests(Pkt) + end. + +%% recv_A/5 + +recv_A(Timeout, SvcName, App, Opts, {TRef, #request{ref = Ref} = Req}) -> + %% Matching on TRef below ensures we ignore messages that pertain + %% to a previous transport prior to failover. The answer message + %% includes the #request{} since it's not necessarily Req; that + %% is, from the last peer to which we've transmitted. + receive + {answer = A, Ref, Rq, Dict0, Pkt} -> %% Answer from peer + {A, Rq, Dict0, Pkt}; + {timeout = Reason, TRef, _} -> %% No timely reply + {error, Req, Reason}; + {failover, TRef} -> %% Service says peer has gone down + retransmit(pick_peer(SvcName, App, Req, Opts), + Req, + Opts, + SvcName, + Timeout) + end. + +%% handle_answer/3 + +handle_answer(SvcName, App, {error, Req, Reason}) -> + handle_error(App, Req, Reason, SvcName); + +handle_answer(SvcName, + #diameter_app{dictionary = Dict} + = App, + {answer, Req, Dict0, Pkt}) -> + Mod = dict(Dict, Dict0, Pkt), + answer(examine(diameter_codec:decode(Mod, Pkt)), + SvcName, + Mod, + App, + Req). + +%% We don't really need to do a full decode if we're a relay and will +%% just resend with a new hop by hop identifier, but might a proxy +%% want to examine the answer? + +answer(Pkt, SvcName, Dict, App, #request{transport = TPid} = Req) -> + try + incr(recv, Pkt, Dict, TPid) + of + _ -> answer(Pkt, SvcName, App, Req) + catch + exit: {invalid_error_bit, _} = E -> + answer(Pkt#diameter_packet{errors = [E]}, SvcName, App, Req) + end. + +answer(Pkt, + SvcName, + #diameter_app{module = ModX, + options = [{answer_errors, AE} | _]}, + Req) -> + a(Pkt, SvcName, ModX, AE, Req). + +a(#diameter_packet{errors = Es} + = Pkt, + SvcName, + ModX, + AE, + #request{transport = TPid, + caps = Caps, + packet = P}) + when [] == Es; + callback == AE -> + cb(ModX, handle_answer, [Pkt, msg(P), SvcName, {TPid, Caps}]); + +a(Pkt, SvcName, _, report, Req) -> + x(errors, handle_answer, [SvcName, Req, Pkt]); + +a(Pkt, SvcName, _, discard, Req) -> + x({errors, handle_answer, [SvcName, Req, Pkt]}). + +%% Note that we don't check that the application id in the answer's +%% header is what we expect. (TODO: Does the rfc says anything about +%% this?) + +%% Note that failover starts a new timer and that expiry of an old +%% timer value is ignored. This means that an answer could be accepted +%% from a peer after timeout in the case of failover. + +retransmit({{_,_,App} = Transport, _Mask}, Req, Opts, SvcName, Timeout) -> + try retransmit(Transport, Req, SvcName, Timeout) of + T -> recv_A(Timeout, SvcName, App, Opts, T) + catch + ?FAILURE(Reason) -> {error, Req, Reason} + end; + +retransmit(_, Req, _, _, _) -> %% no alternate peer + {error, Req, failover}. + +%% pick_peer/4 + +%% Retransmission after failover: call-specific arguments have already +%% been appended in App. +pick_peer(SvcName, + App, + #request{packet = #diameter_packet{msg = Msg}}, + Opts) -> + pick_peer(SvcName, App, Msg, Opts#options{extra = []}); + +pick_peer(_, _, undefined, _) -> + false; + +pick_peer(SvcName, + AppOrAlias, + Msg, + #options{filter = Filter, extra = Xtra}) -> + diameter_service:pick_peer(SvcName, + AppOrAlias, + {fun(D) -> get_destination(D, Msg) end, + Filter, + Xtra}). + +%% handle_error/4 + +handle_error(App, + #request{packet = Pkt, + transport = TPid, + caps = Caps}, + Reason, + SvcName) -> + cb(App, handle_error, [Reason, msg(Pkt), SvcName, {TPid, Caps}]). + +msg(#diameter_packet{msg = undefined, bin = Bin}) -> + Bin; +msg(#diameter_packet{msg = Msg}) -> + Msg. + +%% encode/3 + +encode(Dict, Pkt, Fs) -> + P = encode(Dict, Pkt), + eval_packet(P, Fs), + P. + +%% encode/2 + +%% Note that prepare_request can return a diameter_packet containing a +%% header or transport_data. Even allow the returned record to contain +%% an encoded binary. This isn't the usual case and doesn't properly +%% support retransmission but is useful for test. + +%% A message to be encoded. +encode(Dict, #diameter_packet{bin = undefined} = Pkt) -> + diameter_codec:encode(Dict, Pkt); + +%% An encoded binary: just send. +encode(_, #diameter_packet{} = Pkt) -> + Pkt. + +%% send_request/5 + +send_request(TPid, #diameter_packet{bin = Bin} = Pkt, Req, _SvcName, Timeout) + when node() == node(TPid) -> + %% Store the outgoing request before sending to avoid a race with + %% reply reception. + TRef = store_request(TPid, Bin, Req, Timeout), + send(TPid, Pkt), + TRef; + +%% Send using a remote transport: spawn a process on the remote node +%% to relay the answer. +send_request(TPid, #diameter_packet{} = Pkt, Req, SvcName, Timeout) -> + TRef = erlang:start_timer(Timeout, self(), TPid), + T = {TPid, Pkt, Req, SvcName, Timeout, TRef}, + spawn(node(TPid), ?MODULE, send, [T]), + TRef. + +%% send/1 + +send({TPid, Pkt, #request{handler = Pid} = Req, SvcName, Timeout, TRef}) -> + Ref = send_request(TPid, + Pkt, + Req#request{handler = self()}, + SvcName, + Timeout), + Pid ! reref(receive T -> T end, Ref, TRef). + +reref({T, Ref, R}, Ref, TRef) -> + {T, TRef, R}; +reref(T, _, _) -> + T. + +%% send/2 + +send(Pid, Pkt) -> + Pid ! {send, Pkt}. + +%% retransmit/4 + +retransmit({TPid, Caps, App} + = Transport, + #request{packet = Pkt0} + = Req, + SvcName, + Timeout) -> + have_request(Pkt0, TPid) %% Don't failover to a peer we've + andalso ?THROW(timeout), %% already sent to. + + #diameter_packet{header = Hdr0} = Pkt0, + Hdr = Hdr0#diameter_header{is_retransmitted = true}, + Pkt = Pkt0#diameter_packet{header = Hdr}, + + retransmit(cb(App, prepare_retransmit, [Pkt, SvcName, {TPid, Caps}]), + Transport, + Req#request{packet = Pkt}, + SvcName, + Timeout, + []). + +retransmit({send, Msg}, + Transport, + #request{packet = Pkt} + = Req, + SvcName, + Timeout, + Fs) -> + resend_request(make_request_packet(Msg, Pkt), + Transport, + Req, + SvcName, + Timeout, + Fs); + +retransmit({discard, Reason}, _, _, _, _, _) -> + ?THROW(Reason); + +retransmit(discard, _, _, _, _, _) -> + ?THROW(discarded); + +retransmit({eval_packet, RC, F}, Transport, Req, SvcName, Timeout, Fs) -> + retransmit(RC, Transport, Req, SvcName, Timeout, [F|Fs]); + +retransmit(T, {_, _, App}, _, _, _, _) -> + ?ERROR({invalid_return, prepare_retransmit, App, T}). + +resend_request(Pkt0, + {TPid, Caps, #diameter_app{dictionary = Dict}}, + Req0, + SvcName, + Tmo, + Fs) -> + Pkt = encode(Dict, Pkt0, Fs), + + Req = Req0#request{transport = TPid, + packet = Pkt0, + caps = Caps}, + + ?LOG(retransmission, Req), + TRef = send_request(TPid, Pkt, Req, SvcName, Tmo), + {TRef, Req}. + +%% store_request/4 + +store_request(TPid, Bin, Req, Timeout) -> + Seqs = diameter_codec:sequence_numbers(Bin), + TRef = erlang:start_timer(Timeout, self(), timeout), + ets:insert(?REQUEST_TABLE, {Seqs, Req, TRef}), + ets:member(?REQUEST_TABLE, TPid) + orelse (self() ! {failover, TRef}), %% failover/1 may have missed + TRef. + +%% lookup_request/2 + +lookup_request(Msg, TPid) -> + Seqs = diameter_codec:sequence_numbers(Msg), + Spec = [{{Seqs, #request{transport = TPid, _ = '_'}, '_'}, + [], + ['$_']}], + case ets:select(?REQUEST_TABLE, Spec) of + [{_, Req, _}] -> + Req; + [] -> + false + end. + +%% erase_requests/1 + +erase_requests(Pkt) -> + ets:delete(?REQUEST_TABLE, diameter_codec:sequence_numbers(Pkt)). + +%% match_requests/1 + +match_requests(TPid) -> + Pat = {'_', #request{transport = TPid, _ = '_'}, '_'}, + ets:select(?REQUEST_TABLE, [{Pat, [], ['$_']}]). + +%% have_request/2 + +have_request(Pkt, TPid) -> + Seqs = diameter_codec:sequence_numbers(Pkt), + Pat = {Seqs, #request{transport = TPid, _ = '_'}, '_'}, + '$end_of_table' /= ets:select(?REQUEST_TABLE, [{Pat, [], ['$_']}], 1). + +%% --------------------------------------------------------------------------- +%% # failover/1-2 +%% --------------------------------------------------------------------------- + +failover(TPid) + when is_pid(TPid) -> + lists:foreach(fun failover/1, match_requests(TPid)); +%% Note that a request process can store its request after failover +%% notifications are sent here: store_request/4 sends the notification +%% in that case. + +%% Failover as a consequence of request_peer_down/1: inform the +%% request process. +failover({_, Req, TRef}) -> + #request{handler = Pid, + packet = #diameter_packet{msg = M}} + = Req, + M /= undefined andalso (Pid ! {failover, TRef}). +%% Failover is not performed when msg = binary() since sending +%% pre-encoded binaries is only partially supported. (Mostly for +%% test.) + +%% get_destination/2 + +get_destination(Dict, Msg) -> + [str(get_avp_value(Dict, D, Msg)) || D <- ['Destination-Realm', + 'Destination-Host']]. + +%% This is not entirely correct. The avp could have an arity 1, in +%% which case an empty list is a DiameterIdentity of length 0 rather +%% than the list of no values we treat it as by mapping to undefined. +%% This behaviour is documented. +str([]) -> + undefined; +str(T) -> + T. + +%% get_avp_value/3 +%% +%% Find an AVP in a message of one of three forms: +%% +%% - a message record (as generated from a .dia spec) or +%% - a list of an atom message name followed by 2-tuple, avp name/value pairs. +%% - a list of a #diameter_header{} followed by #diameter_avp{} records, +%% +%% In the first two forms a dictionary module is used at encode to +%% identify the type of the AVP and its arity in the message in +%% question. The third form allows messages to be sent as is, without +%% a dictionary, which is needed in the case of relay agents, for one. + +%% Messages will be header/avps list as a relay and the only AVP's we +%% look for are in the common dictionary. This is required since the +%% relay dictionary doesn't inherit the common dictionary (which maybe +%% it should). +get_avp_value(?RELAY, Name, Msg) -> + get_avp_value(?BASE, Name, Msg); + +%% Message sent as a header/avps list, probably a relay case but not +%% necessarily. +get_avp_value(Dict, Name, [#diameter_header{} | Avps]) -> + try + {Code, _, VId} = Dict:avp_header(Name), + [A|_] = lists:dropwhile(fun(#diameter_avp{code = C, vendor_id = V}) -> + C /= Code orelse V /= VId + end, + Avps), + avp_decode(Dict, Name, A) + catch + error: _ -> + undefined + end; + +%% Outgoing message as a name/values list. +get_avp_value(_, Name, [_MsgName | Avps]) -> + case lists:keyfind(Name, 1, Avps) of + {_, V} -> + V; + _ -> + undefined + end; + +%% Message is typically a record but not necessarily. +get_avp_value(Dict, Name, Rec) -> + try + Dict:'#get-'(Name, Rec) + catch + error:_ -> + undefined + end. + +avp_decode(Dict, Name, #diameter_avp{value = undefined, + data = Bin}) -> + Dict:avp(decode, Bin, Name); +avp_decode(_, _, #diameter_avp{value = V}) -> + V. + +cb(#diameter_app{module = [_|_] = M}, F, A) -> + eval(M, F, A); +cb([_|_] = M, F, A) -> + eval(M, F, A). + +eval([M|X], F, A) -> + apply(M, F, A ++ X). + +choose(true, X, _) -> X; +choose(false, _, X) -> X. + |