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    1/*  Part of SWI-Prolog
    2
    3    Author:        Jeffrey Rosenwald
    4    E-mail:        jeffrose@acm.org
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2009-2013, Jeffrey Rosenwald
    7    All rights reserved.
    8
    9    Redistribution and use in source and binary forms, with or without
   10    modification, are permitted provided that the following conditions
   11    are met:
   12
   13    1. Redistributions of source code must retain the above copyright
   14       notice, this list of conditions and the following disclaimer.
   15
   16    2. Redistributions in binary form must reproduce the above copyright
   17       notice, this list of conditions and the following disclaimer in
   18       the documentation and/or other materials provided with the
   19       distribution.
   20
   21    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   22    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   23    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   24    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   25    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   26    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   27    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   28    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   29    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   31    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   32    POSSIBILITY OF SUCH DAMAGE.
   33*/
   34
   35:- module(tipc,
   36          [ tipc_socket/2,              % -Socket  +Type
   37            tipc_close_socket/1,        % +Socket
   38            tipc_setopt/2,              % +Socket, +Option
   39            tipc_bind/3,                % +Socket, +Address +Scope
   40            tipc_listen/2,              % +Socket, +BackLog
   41            tipc_accept/3,              % +Master, -Slave, -PeerName
   42            tipc_open_socket/3,         % +Socket, -Read, -Write
   43            tipc_get_name/2,            % +Socket, -Address
   44            tipc_get_peer_name/2,       % +Socket, -Address
   45            tipc_connect/2,             % +Socket, +Address
   46            tipc_receive/4,             % +Socket, -Data, -Sender, +Options
   47            tipc_send/4,                % +Socket, +Data, +Receiver, +Options
   48%           tipc_subscribe/5, % +Socket, +Address, +Timeout, +Filter,
   49%           +Usr_handle
   50
   51%           tipc_receive_subscr_event/2, % +Socket, -Event
   52            tipc_canonical_address/2,   % -Address, +port_id/2
   53            tipc_service_probe/1,       % ?Address
   54            tipc_service_probe/2,       % ?Address, ?PortId
   55            tipc_service_port_monitor/2, % +Address, :Goal
   56            tipc_service_port_monitor/3, % +Address, :Goal, +Timeout
   57            tipc_service_exists/1,      % +Address
   58            tipc_service_exists/2,       % +Address +Timeout
   59            tipc_initialize/0            %
   60          ]).   61:- use_module(library(apply)).   62:- use_module(library(lists)).   63:- use_module(library(shlib)).   64:- use_foreign_library(foreign(tipc)).   65
   66:- multifile tipc_stack_initialize/0.

TIPC Sockets

Transparent Inter-Process Communication (TIPC) provides a flexible, reliable, fault-tolerant, high-speed, and low-overhead framework for inter-process communication between federations of trusted peers, operating as a unit. It was developed by Ericsson AB, as a means to provide for communications between Common Control Systems processes and Network Element peers in telephone switching systems, sometimes operating at arm's length on different line cards or mainframes. Delegation of responsibility in this way is one of the fundamental precepts of the Erlang programming system, also developed at Ericsson. TIPC represents a more generalized version of the same behavioral design pattern. For an overview, please see: tipc_overview.md.

Errors

The TIPC module uses the error handling functions from library(socket) and therefore all the functions below may throw error(socket_error(Code, Message)) where Code is the lowercase version of the C-macro error code and Message is an atom describing the error in a human friendly format, depending on the current locale. See the socket library for details.

author
- Jeffrey Rosenwald (JeffRose@acm.org)
See also
- http://tipc.sf.net, http://www.erlang.org
Compatibility
- Linux only */
 tipc_socket(-SocketId, +SocketType) is det
Creates a TIPC-domain socket of the type specified by SocketType, and unifies it to an identifier, SocketId.
Arguments:
SocketType- is one of the following atoms:
  • rdm - unnumbered, reliable datagram service,
  • dgram - unnumbered, unreliable datagram service,
  • seqpacket - numbered, reliable datagram service, and
  • stream - reliable, connection-oriented byte-stream service
 tipc_close_socket(+SocketId) is det
Closes the indicated socket, making SocketId invalid. In stream applications, sockets are closed by closing both stream handles returned by tipc_open_socket/3. There are two cases where tipc_close_socket/1 is used because there are no stream-handles:
Arguments:
SocketId- the socket identifier returned by tipc_socket/2 or tipc_accept/3.
 tipc_subscribe(+SocketId, +NameSeqAddress, +Timeout, +Filter, +UserHandle) is det
Subscribes to events related to a publisher that is bound to the multi-cast address specified in NameSeqAddress.

Timeout specifies the duration of the subscription in milliseconds. Specifying a Timeout of -1, provides for a subscription of infinite duration. Filter specifies the events of interest to the subscriber. It is an integer bit field where:

 tipc_open_socket(+SocketId, -InStream, -OutStream) is det
Opens two SWI-Prolog I/O-streams, one to deal with input from the socket and one with output to the socket. If tipc_bind/3 has been called on the socket, OutStream is useless and will not be created. After closing both InStream and OutStream, the socket itself is discarded.
 tipc_bind(+Socket, +Address, +ScopingOption) is det
Associates/disassociates a socket with the name/3 or name_seq/3 address specified in Address. It also registers/unregisters it in the topology server name table. This makes the address visible/invisible to the rest of the network according to the scope specified in ScopingOption. ScopingOption is a grounded term that is one of:
scope(Scope)
where Scope is one of: zone, cluster, or node. Servers may bind to more than one address by making successive calls to tipc_bind/3, one for each address that it wishes to advertise. The server will receive traffic for all of them. A server may, for example, register one address with node scope, another with cluster scope, and a third with zone scope. A client may then limit the scope of its transmission by specifying the appropriate address.
no_scope(Scope)
where Scope is as defined above. An application may target a specific address for removal from its collection of addresses by specifying the address and its scope. The scoping option, no_scope(all), may be used to unbind the socket from all of its registered addresses. This feature allows an application to gracefully exit from service. Because the socket remains open, the application may continue to service current transactions to completion. TIPC however, will not schedule any new work for the server instance. If no other servers are available, the work will be rejected or dropped according to the socket options specified by the client.

Connection-oriented, byte-stream services are implemented with this predicate combined with tipc_listen/2 and tipc_accept/3. Connectionless, datagram services may be implemented using tipc_receive/4.

Note that clients do not need to bind to any address. Its port-id is sufficient for this role. And server sockets (e.g. those that are bound to name/3 or name_seq/3, addresses) may not act as clients. That is, they may not originate connections from the socket using tipc_connect/2. Servers however, may originate datagrams from bound sockets using tipc_send/4. Please see the TIPC programmers's guide for other restrictions.

 tipc_listen(+Socket, +Backlog) is det
Listens for incoming requests for connections. Backlog indicates how many pending connection requests are allowed. Pending requests are requests that are not yet acknowledged using tipc_accept/3. If the indicated number is exceeded, the requesting client will be signalled that the service is currently not available. A suggested default value is 5.
 tipc_accept(+Socket, -Slave, -Peer) is det
Blocks on a server socket and waits for connection requests from clients. On success, it creates a new socket for the client and binds the identifier to Slave. Peer is bound to the TIPC address, port_id/2, of the client.
 tipc_connect(+Socket, +TIPC_address) is det
Provides a connection-oriented, client-interface to connect a socket to a given TIPC_address. After successful completion, tipc_open_socket/3 may be used to create I/O-Streams to the remote socket.
 tipc_get_name(+Socket, -TIPC_address) is det
Unifies TIPC_address with the port-id assigned to the socket.
 tipc_get_peer_name(+Socket, -TIPC_address) is det
Unifies TIPC_address with the port-id assigned to the socket that this socket is connected to.
 tipc_setopt(+Socket, +Option) is det
Sets options on the socket. Defined options are:
importance(+Priority)
Allow sockets to assign a priority to their traffic. Priority is one of : low (default), medium, high, or critical.
src_droppable(+Boolean)
Allow TIPC to silently discard packets in congested situations, rather than queuing them for later transmission.
dest_droppable(+Boolean)
Allow TIPC to silently discard packets in congested situations, rather than returning them to the sender as undeliverable.
conn_timeout(+Seconds)
Specifies the time interval that tipc_connect/2 will use before abandoning a connection attempt. Default: 8.000 sec.
 tipc_receive(+Socket, -Data, -From, +OptionList) is det
Waits for, and returns the next datagram. Like its UDP counterpart, the data are returned as a Prolog string object (see string_codes/2). From is an address structure of the form port_id/2, indicating the sender of the message.

Defined options are:

as(+Type)
Defines the returned term-type. Type is one of atom, codes or string (default).
nonblock
Poll the socket and return immediately. If a message is present, it is returned. If not, then an exception, error(socket_error(eagain, Message), _), will be thrown. Users are cautioned not to "spin" unnecessarily on non-blocking receives as they may prevent the system from servicing other background activities such as XPCE event dispatching.

The typical sequence to receive a connectionless TIPC datagram is:

receive :-
        tipc_socket(S, dgram),
        tipc_bind(S, name(18888, 10, 0), scope(zone)),
        repeat,
            tipc_receive(Socket, Data, From, [as(atom)]),
            format('Got ~q from ~q~n', [Data, From]),
            Data == quit,
        !, tipc_close_socket(S).
 tipc_send(+Socket, +Data, +To, +Options) is det
sends a TIPC datagram to one or more destinations. Like its UDP counterpart, Data is a string, atom or code-list providing the data to be sent. To is a name/3, name_seq/3, or port_id/2 address structure. See tipc_overview.txt, for more information on TIPC Address Structures. Options is currently unused.

A simple example to send a connectionless TIPC datagram is:

send(Message) :-
        tipc_socket(S, dgram),
        tipc_send(S, Message, name(18888, 10,0), []),
        tipc_close_socket(S).

Messages are delivered silently unless some form of congestion was encountered and the dest_droppable(false) option was issued on the sender's socket. In this case, the send succeeds but a notification in the form of an empty message is returned to the sender from the receiver, indicating some kind of delivery failure. The port-id of the receiver is returned in congestion conditions. A port_id(0,0), is returned if the destination address was invalid. Senders and receivers should beware of this possibility.

 tipc_event(+Data, -Event, -Residue) is det
Parses event notifications received from the topology server into Prolog structures. This predicate has been permanently removed.
 tipc_receive_subscr_event(+Socket, -Event) is semidet
Receives and parses event notifications received from the TIPC Topology Server.

Please note that this predicate is considered private. Its use in user programs is strongly discouraged. See the tipc-service predicates for alternatives.

Arguments:
Socket- is a TIPC socket that has been previously connected to the topology server using tipc_connect/2, and for which a subscription has been sent using tipc_subscribe/5, above.
Event- is the structure: tipc_event(-Action, -Subscr, -Found, -Port_id). On subscription timeout, the atom, subscr_timeout is returned. Subscr is the name-sequence address of the original subscription.

Action is one of:

published
The socket specified by Port_id has been bound to the name_seq/3 address specified in Found.
withdrawn
The socket specified by Port_id has been unbound from the name_seq/3 address specified in Found. See the no_scope/1 option of tipc_bind/3.
  386:- multifile
  387    prolog:message/3.  388
  389prolog:message(error(socket_error(_Code, Message), _)) -->
  390    [ 'Socket error: ~w'-[Message] ].
 tipc_canonical_address(-CanonicalAddress, +PortId) is det
Translates a port_id/2 address into canonical TIPC form:
tipc_address(Zone, Cluster, Node, Reference)
It is provided for debugging an printing purposes only. The canonical address is not used for any other purpose.
  401integerAsU32(In, Out) :-
  402    nonvar(In),
  403    (   In < 0
  404    ->  Out is In + 0x100000000
  405    ;   Out is In
  406    ).
  407integerAsU32(In, Out) :-
  408    nonvar(Out),
  409    (   Out > 0x7fffffff
  410    ->  In is Out - 0x100000000
  411    ;   In is Out
  412    ).
  413
  414tipc_canonical_address(tipc_address(Z,C,N, Ref1), port_id(Ref, Node)) :-
  415    integerAsU32(Ref, Ref1),
  416    integerAsU32(Node, X),
  417    Z is (X >> 24) /\ 0xFF,
  418    C is (X >> 12) /\ 0xFFF,
  419    N is X /\ 0xFFF.
  420
  421user:portray(port_id(Ref, Node)) :-
  422    tipc_canonical_address(tipc_address(Z,C,N, Ref1), port_id(Ref, Node)),
  423    format('port_id(''<~w.~w.~w:~w>'')', [Z,C,N, Ref1]).
 tipc_service_exists(+Address, +Timeout) is semidet
 tipc_service_exists(+Address) is semidet
Interrogates the TIPC topology server to see if a service is available at an advertised Address.
Arguments:
Address- is one of: name(Type, Instance, Domain) or name_seq(Type, Lower, Upper). A name/3, address is translated to a name_seq/3, following, where Lower and Upper are assigned the value of Instance. Domain is unused and must be zero. A name_seq(Type, Lower, Upper) is a multi-cast address. This predicate succeeds if there is at least one service that would answer according to multi-cast addressing rules.
Timeout- is optional. It is a non-negative real number that specifies the amount of time in seconds to block and wait for a service to become available. Fractions of a second are also permissible.
  446tipc_address(name(T, I, 0), name_seq(T, I, I)).
  447tipc_address(name_seq(T, L, U), name_seq(T, L, U)).
  448tipc_address(mcast(T, L, U), name_seq(T, L, U)).
  449%
  450%
  451
  452tipc_service_exists(Address) :-
  453    tipc_service_exists(Address, 0.0).
  454
  455tipc_service_exists(Address, Timeout) :-
  456    tipc_address(Address, NameSeq),
  457    !,
  458    ITime is integer(Timeout * 1000),
  459    try_finally(tipc_socket(S, seqpacket),
  460                tipc_close_socket(S)),
  461    tipc_connect(S, name(1,1,0)),   % connect to the topology server
  462    tipc_subscribe(S, NameSeq, ITime, 2, "swipl"),
  463    repeat,
  464        tipc_receive_subscr_event(S, Data),
  465        (   Data == subscr_timeout
  466        ->  !, fail
  467        ;   Data = tipc_event(published, NameSeq, _FoundSeq, _Port_id)
  468        ),
  469    !.
 tipc_service_probe(?Address) is nondet
 tipc_service_probe(?Address, ?PortId) is nondet
Allows a user to discover the instance ranges and/or port-ids for a particular service.
Arguments:
Address- is a name_seq/3 address. The address type must be grounded.
PortId- is unified with the port-id for a specific name_sequence address.
  483try_finally(Setup, Cleanup) :-
  484    setup_call_cleanup(Setup, ( Solution = yes ; Solution = no ), Cleanup),
  485    Solution = yes.
  486
  487tipc_service_probe(Address) :-
  488    tipc_address(Address, name_seq(Type, Lower, Upper)),
  489    integer(Type),
  490    NameSeq = name_seq(Type, Lower, Upper),
  491    try_finally(tipc_socket(S, seqpacket), tipc_close_socket(S)),
  492    tipc_connect(S, name(1,1,0)),   % connect to the topology server
  493    tipc_subscribe(S, name_seq(Type, 0, 4294967295), 0, 2, "swipl"),  % look for everything
  494    sp_collect(S, Members),
  495    !,
  496    member([NameSeq, _], Members).
  497
  498tipc_service_probe(Address, PortId) :-
  499    tipc_address(Address, name_seq(Type, Lower, Upper)),
  500    integer(Type),
  501    NameSeq = name_seq(Type, Lower, Upper),
  502    try_finally(tipc_socket(S, seqpacket), tipc_close_socket(S)),
  503    tipc_connect(S, name(1,1,0)),   % connect to the topology server
  504    tipc_subscribe(S, name_seq(Type, 0, 4294967295), 0, 1, "swipl"),  % look for everything
  505    sp_collect(S, Members),
  506    !,
  507    member([NameSeq, PortId], Members).
  508
  509sp_collect(S, Members) :-
  510    findall([NameSeq, PortId],
  511        ( repeat,
  512          tipc_receive_subscr_event(S, Data),
  513          (   Data == subscr_timeout
  514              ->  !, fail
  515              ;   Data = tipc_event(published, _Service, NameSeq, PortId)
  516          )
  517        ), Members).
 tipc_service_port_monitor(+Addresses, :Goal) is det
 tipc_service_port_monitor(+Addresses, :Goal, ?Timeout) is det
Monitors a collection of worker threads that are bound to a list of Addresses. A single port monitor may be used to provide surveillance over workers that are providing a number of different services. For a given address type, discontiguous port ranges may be specified, but overlapping port ranges may not. Goal for example, may simply choose to broadcast the notification, thus delegating the notification event handling to others.
Arguments:
Addresses- is a list of name/3 or name_seq/3 addresses for the services to be monitored.
Goal- is a predicate that will be called when a worker's publication status changes. The Goal is called exactly once per event with its the last argument unified with the structure:
published(-NameSeq, -PortId)
when the worker binds its socket to the address.
withdrawn(-NameSeq, -PortId)
when the worker unbinds its socket from the address.
Timeout- is optional. It is one of:
Timeout
a non-negative real number that specifies the number of seconds that surveillance is to be continued.
infinite
causes the monitor to run forever in the current thread (e.g. never returns).
detached(-ThreadId)
causes the monitor to run forever as a separate thread. ThreadId is unified with the thread identifier of the monitor thread. This is useful when the monitor is required to provide continuous surveillance, while operating in the background.
  560spm_dispatch(_Goal, subscr_timeout) :- !.
  561spm_dispatch(Goal, tipc_event(Action, _Subscr, NameSeq, PortId)) :-
  562    Event =.. [Action, NameSeq, PortId],
  563    once(call(Goal, Event)), fail.
  564
  565:- meta_predicate
  566    tipc_service_port_monitor(+, 1),
  567    tipc_service_port_monitor(+, 1, +).  568
  569tipc_service_port_monitor(Address, Goal) :-
  570    tipc_service_port_monitor(Address, Goal, 0.0),
  571    !.
  572
  573tipc_service_port_monitor(Address, Goal, detached(ThreadId)) :-
  574    !,
  575    thread_create(tipc_service_port_monitor(Address, Goal, infinite),
  576                  ThreadId, [detached(true)]).
  577tipc_service_port_monitor(Address, Goal, infinite) :-
  578    tipc_service_port_monitor(Address, Goal, -0.001),
  579    !.
  580
  581tipc_service_port_monitor(Addresses, Goal, Timeout) :-
  582    maplist(tipc_address,Addresses, NameSeqs),
  583    !,
  584    ITime is integer(Timeout * 1000),
  585    try_finally(tipc_socket(S, seqpacket), tipc_close_socket(S)),
  586    tipc_connect(S, name(1,1,0)),   % connect to the topology server
  587    forall(member(NameSeq, NameSeqs),
  588           tipc_subscribe(S, NameSeq, ITime, 1, "swipl")),
  589    repeat,
  590        tipc_receive_subscr_event(S, Data),
  591        spm_dispatch(Goal, Data),
  592    !.
 tipc_initialize is semidet
causes the TIPC service and the TIPC stack to be initialized and made ready for service. An application must call this predicate as part of its initialization prior to any use of TIPC predicates. Please note the change of the API.
  601tipc_initialize :-
  602    with_mutex(tipc_mutex,
  603               forall(tipc_stack_initialize, true)).
  604
  605tipc_stack_initialize :-
  606    tipc_service_exists(name(1,1,0))