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Diffstat (limited to 'lib/diameter/src/app/diameter_session.erl')
| -rw-r--r-- | lib/diameter/src/app/diameter_session.erl | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/lib/diameter/src/app/diameter_session.erl b/lib/diameter/src/app/diameter_session.erl new file mode 100644 index 0000000000..bb91e97f39 --- /dev/null +++ b/lib/diameter/src/app/diameter_session.erl @@ -0,0 +1,172 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 2010-2011. 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% +%% + +-module(diameter_session). + +-export([sequence/0, + session_id/1, + origin_state_id/0]). + +%% towards diameter_sup +-export([init/0]). + +-include("diameter_types.hrl"). + +-define(INT64, 16#FFFFFFFFFFFFFFFF). +-define(INT32, 16#FFFFFFFF). + +%% --------------------------------------------------------------------------- +%% # sequence/0 +%% +%% Output: 32-bit +%% --------------------------------------------------------------------------- + +%% 3588, 3: +%% +%% Hop-by-Hop Identifier +%% The Hop-by-Hop Identifier is an unsigned 32-bit integer field (in +%% network byte order) and aids in matching requests and replies. +%% The sender MUST ensure that the Hop-by-Hop identifier in a request +%% is unique on a given connection at any given time, and MAY attempt +%% to ensure that the number is unique across reboots. The sender of +%% an Answer message MUST ensure that the Hop-by-Hop Identifier field +%% contains the same value that was found in the corresponding +%% request. The Hop-by-Hop identifier is normally a monotonically +%% increasing number, whose start value was randomly generated. An +%% answer message that is received with an unknown Hop-by-Hop +%% Identifier MUST be discarded. +%% +%% End-to-End Identifier +%% The End-to-End Identifier is an unsigned 32-bit integer field (in +%% network byte order) and is used to detect duplicate messages. +%% Upon reboot implementations MAY set the high order 12 bits to +%% contain the low order 12 bits of current time, and the low order +%% 20 bits to a random value. Senders of request messages MUST +%% insert a unique identifier on each message. The identifier MUST +%% remain locally unique for a period of at least 4 minutes, even +%% across reboots. The originator of an Answer message MUST ensure +%% that the End-to-End Identifier field contains the same value that +%% was found in the corresponding request. The End-to-End Identifier +%% MUST NOT be modified by Diameter agents of any kind. The +%% combination of the Origin-Host (see Section 6.3) and this field is +%% used to detect duplicates. Duplicate requests SHOULD cause the +%% same answer to be transmitted (modulo the hop-by-hop Identifier +%% field and any routing AVPs that may be present), and MUST NOT +%% affect any state that was set when the original request was +%% processed. Duplicate answer messages that are to be locally +%% consumed (see Section 6.2) SHOULD be silently discarded. + +-spec sequence() + -> 'Unsigned32'(). + +sequence() -> + Instr = {_Pos = 2, _Incr = 1, _Threshold = ?INT32, _SetVal = 0}, + ets:update_counter(diameter_sequence, sequence, Instr). + +%% --------------------------------------------------------------------------- +%% # origin_state_id/0 +%% --------------------------------------------------------------------------- + +%% 3588, 8.16: +%% +%% The Origin-State-Id AVP (AVP Code 278), of type Unsigned32, is a +%% monotonically increasing value that is advanced whenever a Diameter +%% entity restarts with loss of previous state, for example upon reboot. +%% Origin-State-Id MAY be included in any Diameter message, including +%% CER. +%% +%% A Diameter entity issuing this AVP MUST create a higher value for +%% this AVP each time its state is reset. A Diameter entity MAY set +%% Origin-State-Id to the time of startup, or it MAY use an incrementing +%% counter retained in non-volatile memory across restarts. + +-spec origin_state_id() + -> 'Unsigned32'(). + +origin_state_id() -> + ets:lookup_element(diameter_sequence, origin_state_id, 2). + +%% --------------------------------------------------------------------------- +%% # session_id/1 +%% --------------------------------------------------------------------------- + +%% 3588, 8.8: +%% +%% The Session-Id MUST begin with the sender's identity encoded in the +%% DiameterIdentity type (see Section 4.4). The remainder of the +%% Session-Id is delimited by a ";" character, and MAY be any sequence +%% that the client can guarantee to be eternally unique; however, the +%% following format is recommended, (square brackets [] indicate an +%% optional element): +%% +%% <DiameterIdentity>;<high 32 bits>;<low 32 bits>[;<optional value>] +%% +%% <high 32 bits> and <low 32 bits> are decimal representations of the +%% high and low 32 bits of a monotonically increasing 64-bit value. The +%% 64-bit value is rendered in two part to simplify formatting by 32-bit +%% processors. At startup, the high 32 bits of the 64-bit value MAY be +%% initialized to the time, and the low 32 bits MAY be initialized to +%% zero. This will for practical purposes eliminate the possibility of +%% overlapping Session-Ids after a reboot, assuming the reboot process +%% takes longer than a second. Alternatively, an implementation MAY +%% keep track of the increasing value in non-volatile memory. +%% +%% <optional value> is implementation specific but may include a modem's +%% device Id, a layer 2 address, timestamp, etc. + +-spec session_id('DiameterIdentity'()) + -> 'OctetString'(). +%% Note that Session-Id has type UTF8String and that any OctetString +%% is a UTF8String. + +session_id(Host) -> + Instr = {_Pos = 2, _Incr = 1, _Threshold = ?INT64, _Set = 0}, + N = ets:update_counter(diameter_sequence, session_base, Instr), + Hi = N bsr 32, + Lo = N band ?INT32, + [Host, ";", integer_to_list(Hi), + ";", integer_to_list(Lo), + ";", atom_to_list(node())]. + +%% --------------------------------------------------------------------------- +%% # init/0 +%% --------------------------------------------------------------------------- + +init() -> + Now = now(), + random:seed(Now), + Time = time32(Now), + Seq = (?INT32 band (Time bsl 20)) bor (random:uniform(1 bsl 20) - 1), + ets:insert(diameter_sequence, [{origin_state_id, Time}, + {session_base, Time bsl 32}, + {sequence, Seq}]), + Time. + +%% --------------------------------------------------------- +%% INTERNAL FUNCTIONS +%% --------------------------------------------------------- + +%% The minimum value represented by a Time value. (See diameter_types.) +%% 32 bits extends to 2104. +-define(TIME0, 62105714048). %% {{1968,1,20},{3,14,8}} + +time32(Now) -> + Time = calendar:now_to_universal_time(Now), + Diff = calendar:datetime_to_gregorian_seconds(Time) - ?TIME0, + Diff band ?INT32. |