1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- G N A T . S O C K E T S --
9 -- Copyright (C) 2001-2007, AdaCore --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 -- This package provides an interface to the sockets communication facility
35 -- provided on many operating systems. This is implemented on the following
38 -- All native ports, with restrictions as follows
40 -- Multicast is available only on systems which provide support for this
41 -- feature, so it is not available if Multicast is not supported, or not
42 -- installed. In particular Multicast is not available with the Windows
45 -- The VMS implementation was implemented using the DECC RTL Socket API,
46 -- and is thus subject to limitations in the implementation of this API.
48 -- VxWorks cross ports fully implement this package
50 -- This package is not yet implemented on LynxOS or other cross ports
54 with Ada.Unchecked_Deallocation;
58 package GNAT.Sockets is
60 -- Sockets are designed to provide a consistent communication facility
61 -- between applications. This package provides an Ada-like interface
62 -- similar to that proposed as part of the BSD socket layer.
64 -- GNAT.Sockets has been designed with several ideas in mind
66 -- This is a system independent interface. Therefore, we try as much as
67 -- possible to mask system incompatibilities. Some functionalities are not
68 -- available because there are not fully supported on some systems.
70 -- This is a thick binding. For instance, a major effort has been done to
71 -- avoid using memory addresses or untyped ints. We preferred to define
72 -- streams and enumeration types. Errors are not returned as returned
73 -- values but as exceptions.
75 -- This package provides a POSIX-compliant interface (between two
76 -- different implementations of the same routine, we adopt the one closest
77 -- to the POSIX specification). For instance, using select(), the
78 -- notification of an asynchronous connect failure is delivered in the
79 -- write socket set (POSIX) instead of the exception socket set (NT).
81 -- Here is a typical example of what you can do:
83 -- with GNAT.Sockets; use GNAT.Sockets;
86 -- with Ada.Exceptions; use Ada.Exceptions;
88 -- procedure PingPong is
90 -- Group : constant String := "239.255.128.128";
91 -- -- Multicast group: administratively scoped IP address
99 -- Address : Sock_Addr_Type;
100 -- Server : Socket_Type;
101 -- Socket : Socket_Type;
102 -- Channel : Stream_Access;
107 -- -- Get an Internet address of a host (here the local host name).
108 -- -- Note that a host can have several addresses. Here we get
109 -- -- the first one which is supposed to be the official one.
111 -- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
113 -- -- Get a socket address that is an Internet address and a port
115 -- Address.Port := 5876;
117 -- -- The first step is to create a socket. Once created, this
118 -- -- socket must be associated to with an address. Usually only a
119 -- -- server (Pong here) needs to bind an address explicitly. Most
120 -- -- of the time clients can skip this step because the socket
121 -- -- routines will bind an arbitrary address to an unbound socket.
123 -- Create_Socket (Server);
125 -- -- Allow reuse of local addresses
130 -- (Reuse_Address, True));
132 -- Bind_Socket (Server, Address);
134 -- -- A server marks a socket as willing to receive connect events
136 -- Listen_Socket (Server);
138 -- -- Once a server calls Listen_Socket, incoming connects events
139 -- -- can be accepted. The returned Socket is a new socket that
140 -- -- represents the server side of the connection. Server remains
141 -- -- available to receive further connections.
143 -- Accept_Socket (Server, Socket, Address);
145 -- -- Return a stream associated to the connected socket
147 -- Channel := Stream (Socket);
149 -- -- Force Pong to block
153 -- -- Receive and print message from client Ping
156 -- Message : String := String'Input (Channel);
159 -- Ada.Text_IO.Put_Line (Message);
161 -- -- Send same message back to client Ping
163 -- String'Output (Channel, Message);
166 -- Close_Socket (Server);
167 -- Close_Socket (Socket);
169 -- -- Part of the multicast example
171 -- -- Create a datagram socket to send connectionless, unreliable
172 -- -- messages of a fixed maximum length.
174 -- Create_Socket (Socket, Family_Inet, Socket_Datagram);
176 -- -- Allow reuse of local addresses
181 -- (Reuse_Address, True));
183 -- -- Controls the live time of the datagram to avoid it being
184 -- -- looped forever due to routing errors. Routers decrement
185 -- -- the TTL of every datagram as it traverses from one network
186 -- -- to another and when its value reaches 0 the packet is
187 -- -- dropped. Default is 1.
191 -- IP_Protocol_For_IP_Level,
192 -- (Multicast_TTL, 1));
194 -- -- Want the data you send to be looped back to your host
198 -- IP_Protocol_For_IP_Level,
199 -- (Multicast_Loop, True));
201 -- -- If this socket is intended to receive messages, bind it
202 -- -- to a given socket address.
204 -- Address.Addr := Any_Inet_Addr;
205 -- Address.Port := 55505;
207 -- Bind_Socket (Socket, Address);
209 -- -- Join a multicast group
211 -- -- Portability note: On Windows, this option may be set only
212 -- -- on a bound socket.
216 -- IP_Protocol_For_IP_Level,
217 -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
219 -- -- If this socket is intended to send messages, provide the
220 -- -- receiver socket address.
222 -- Address.Addr := Inet_Addr (Group);
223 -- Address.Port := 55506;
225 -- Channel := Stream (Socket, Address);
227 -- -- Receive and print message from client Ping
230 -- Message : String := String'Input (Channel);
233 -- -- Get the address of the sender
235 -- Address := Get_Address (Channel);
236 -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
238 -- -- Send same message back to client Ping
240 -- String'Output (Channel, Message);
243 -- Close_Socket (Socket);
247 -- exception when E : others =>
248 -- Ada.Text_IO.Put_Line
249 -- (Exception_Name (E) & ": " & Exception_Message (E));
258 -- Address : Sock_Addr_Type;
259 -- Socket : Socket_Type;
260 -- Channel : Stream_Access;
265 -- -- See comments in Ping section for the first steps
267 -- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
268 -- Address.Port := 5876;
269 -- Create_Socket (Socket);
274 -- (Reuse_Address, True));
276 -- -- Force Pong to block
280 -- -- If the client's socket is not bound, Connect_Socket will
281 -- -- bind to an unused address. The client uses Connect_Socket to
282 -- -- create a logical connection between the client's socket and
283 -- -- a server's socket returned by Accept_Socket.
285 -- Connect_Socket (Socket, Address);
287 -- Channel := Stream (Socket);
289 -- -- Send message to server Pong
291 -- String'Output (Channel, "Hello world");
293 -- -- Force Ping to block
297 -- -- Receive and print message from server Pong
299 -- Ada.Text_IO.Put_Line (String'Input (Channel));
300 -- Close_Socket (Socket);
302 -- -- Part of multicast example. Code similar to Pong's one
304 -- Create_Socket (Socket, Family_Inet, Socket_Datagram);
309 -- (Reuse_Address, True));
313 -- IP_Protocol_For_IP_Level,
314 -- (Multicast_TTL, 1));
318 -- IP_Protocol_For_IP_Level,
319 -- (Multicast_Loop, True));
321 -- Address.Addr := Any_Inet_Addr;
322 -- Address.Port := 55506;
324 -- Bind_Socket (Socket, Address);
328 -- IP_Protocol_For_IP_Level,
329 -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
331 -- Address.Addr := Inet_Addr (Group);
332 -- Address.Port := 55505;
334 -- Channel := Stream (Socket, Address);
336 -- -- Send message to server Pong
338 -- String'Output (Channel, "Hello world");
340 -- -- Receive and print message from server Pong
343 -- Message : String := String'Input (Channel);
346 -- Address := Get_Address (Channel);
347 -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
350 -- Close_Socket (Socket);
354 -- exception when E : others =>
355 -- Ada.Text_IO.Put_Line
356 -- (Exception_Name (E) & ": " & Exception_Message (E));
368 procedure Initialize;
369 -- Initialize must be called before using any other socket routines.
370 -- Note that this operation is a no-op on UNIX platforms, but applications
371 -- should make sure to call it if portability is expected: some platforms
372 -- (such as Windows) require initialization before any socket operation.
374 procedure Initialize (Process_Blocking_IO : Boolean);
376 (Entity => Initialize,
377 "passing a parameter to Initialize is not supported anymore");
378 -- Previous versions of GNAT.Sockets used to require the user to indicate
379 -- whether socket I/O was process- or thread-blocking on the platform.
380 -- This property is now determined automatically when the run-time library
381 -- is built. The old version of Initialize, taking a parameter, is kept
382 -- for compatibility reasons, but this interface is obsolete (and if the
383 -- value given is wrong, an exception will be raised at run time).
386 -- After Finalize is called it is not possible to use any routines
387 -- exported in by this package. This procedure is idempotent.
389 type Socket_Type is private;
390 -- Sockets are used to implement a reliable bi-directional point-to-point,
391 -- stream-based connections between hosts. No_Socket provides a special
392 -- value to denote uninitialized sockets.
394 No_Socket : constant Socket_Type;
396 Socket_Error : exception;
397 -- There is only one exception in this package to deal with an error during
398 -- a socket routine. Once raised, its message contains a string describing
401 function Image (Socket : Socket_Type) return String;
402 -- Return a printable string for Socket
404 function To_C (Socket : Socket_Type) return Integer;
405 -- Return a file descriptor to be used by external subprograms. This is
406 -- useful for C functions that are not yet interfaced in this package.
408 type Family_Type is (Family_Inet, Family_Inet6);
409 -- Address family (or protocol family) identifies the communication domain
410 -- and groups protocols with similar address formats. IPv6 will soon be
413 type Mode_Type is (Socket_Stream, Socket_Datagram);
414 -- Stream sockets provide connection-oriented byte streams. Datagram
415 -- sockets support unreliable connectionless message based communication.
417 type Shutmode_Type is (Shut_Read, Shut_Write, Shut_Read_Write);
418 -- When a process closes a socket, the policy is to retain any data queued
419 -- until either a delivery or a timeout expiration (in this case, the data
420 -- are discarded). A finer control is available through shutdown. With
421 -- Shut_Read, no more data can be received from the socket. With_Write, no
422 -- more data can be transmitted. Neither transmission nor reception can be
423 -- performed with Shut_Read_Write.
425 type Port_Type is new Natural;
426 -- Classical port definition. No_Port provides a special value to
427 -- denote uninitialized port. Any_Port provides a special value
428 -- enabling all ports.
430 Any_Port : constant Port_Type;
431 No_Port : constant Port_Type;
433 type Inet_Addr_Type (Family : Family_Type := Family_Inet) is private;
434 -- An Internet address depends on an address family (IPv4 contains 4
435 -- octets and Ipv6 contains 16 octets). Any_Inet_Addr is a special value
436 -- treated like a wildcard enabling all addresses. No_Inet_Addr provides a
437 -- special value to denote uninitialized inet addresses.
439 Any_Inet_Addr : constant Inet_Addr_Type;
440 No_Inet_Addr : constant Inet_Addr_Type;
441 Broadcast_Inet_Addr : constant Inet_Addr_Type;
443 type Sock_Addr_Type (Family : Family_Type := Family_Inet) is record
444 Addr : Inet_Addr_Type (Family);
447 -- Socket addresses fully define a socket connection with protocol family,
448 -- an Internet address and a port. No_Sock_Addr provides a special value
449 -- for uninitialized socket addresses.
451 No_Sock_Addr : constant Sock_Addr_Type;
453 function Image (Value : Inet_Addr_Type) return String;
454 -- Return an image of an Internet address. IPv4 notation consists in 4
455 -- octets in decimal format separated by dots. IPv6 notation consists in
456 -- 16 octets in hexadecimal format separated by colons (and possibly
459 function Image (Value : Sock_Addr_Type) return String;
460 -- Return inet address image and port image separated by a colon
462 function Inet_Addr (Image : String) return Inet_Addr_Type;
463 -- Convert address image from numbers-and-dots notation into an
466 -- Host entries provide complete information on a given host: the official
467 -- name, an array of alternative names or aliases and array of network
471 (Aliases_Length, Addresses_Length : Natural) is private;
473 function Official_Name (E : Host_Entry_Type) return String;
474 -- Return official name in host entry
476 function Aliases_Length (E : Host_Entry_Type) return Natural;
477 -- Return number of aliases in host entry
479 function Addresses_Length (E : Host_Entry_Type) return Natural;
480 -- Return number of addresses in host entry
483 (E : Host_Entry_Type;
484 N : Positive := 1) return String;
485 -- Return N'th aliases in host entry. The first index is 1
488 (E : Host_Entry_Type;
489 N : Positive := 1) return Inet_Addr_Type;
490 -- Return N'th addresses in host entry. The first index is 1
492 Host_Error : exception;
493 -- Exception raised by the two following procedures. Once raised, its
494 -- message contains a string describing the error code. This exception is
495 -- raised when an host entry cannot be retrieved.
497 function Get_Host_By_Address
498 (Address : Inet_Addr_Type;
499 Family : Family_Type := Family_Inet) return Host_Entry_Type;
500 -- Return host entry structure for the given Inet address. Note that no
501 -- result will be returned if there is no mapping of this IP address to a
502 -- host name in the system tables (host database, DNS or otherwise).
504 function Get_Host_By_Name
505 (Name : String) return Host_Entry_Type;
506 -- Return host entry structure for the given host name. Here name is
507 -- either a host name, or an IP address. If Name is an IP address, this is
508 -- equivalent to Get_Host_By_Address (Inet_Addr (Name)).
510 function Host_Name return String;
511 -- Return the name of the current host
513 type Service_Entry_Type (Aliases_Length : Natural) is private;
514 -- Service entries provide complete information on a given service: the
515 -- official name, an array of alternative names or aliases and the port
518 function Official_Name (S : Service_Entry_Type) return String;
519 -- Return official name in service entry
521 function Port_Number (S : Service_Entry_Type) return Port_Type;
522 -- Return port number in service entry
524 function Protocol_Name (S : Service_Entry_Type) return String;
525 -- Return Protocol in service entry (usually UDP or TCP)
527 function Aliases_Length (S : Service_Entry_Type) return Natural;
528 -- Return number of aliases in service entry
531 (S : Service_Entry_Type;
532 N : Positive := 1) return String;
533 -- Return N'th aliases in service entry (the first index is 1)
535 function Get_Service_By_Name
537 Protocol : String) return Service_Entry_Type;
538 -- Return service entry structure for the given service name
540 function Get_Service_By_Port
542 Protocol : String) return Service_Entry_Type;
543 -- Return service entry structure for the given service port number
545 Service_Error : exception;
546 -- Comment required ???
548 -- Errors are described by an enumeration type. There is only one
549 -- exception Socket_Error in this package to deal with an error during a
550 -- socket routine. Once raised, its message contains the error code
551 -- between brackets and a string describing the error code.
553 -- The name of the enumeration constant documents the error condition
558 Address_Already_In_Use,
559 Cannot_Assign_Requested_Address,
560 Address_Family_Not_Supported_By_Protocol,
561 Operation_Already_In_Progress,
563 Software_Caused_Connection_Abort,
565 Connection_Reset_By_Peer,
566 Destination_Address_Required,
570 Operation_Now_In_Progress,
571 Interrupted_System_Call,
574 Transport_Endpoint_Already_Connected,
575 Too_Many_Symbolic_Links,
580 Network_Dropped_Connection_Because_Of_Reset,
581 Network_Is_Unreachable,
582 No_Buffer_Space_Available,
583 Protocol_Not_Available,
584 Transport_Endpoint_Not_Connected,
585 Socket_Operation_On_Non_Socket,
586 Operation_Not_Supported,
587 Protocol_Family_Not_Supported,
588 Protocol_Not_Supported,
589 Protocol_Wrong_Type_For_Socket,
590 Cannot_Send_After_Transport_Endpoint_Shutdown,
591 Socket_Type_Not_Supported,
592 Connection_Timed_Out,
594 Resource_Temporarily_Unavailable,
596 Host_Name_Lookup_Failure,
597 Non_Recoverable_Error,
598 Unknown_Server_Error,
599 Cannot_Resolve_Error);
601 -- Timeval_Duration is a subtype of Standard.Duration because the full
602 -- range of Standard.Duration cannot be represented in the equivalent C
603 -- structure. Moreover, negative values are not allowed to avoid system
604 -- incompatibilities.
606 Immediate : constant := 0.0;
607 Forever : constant := Duration (Integer'Last) * 1.0;
609 subtype Timeval_Duration is Duration range Immediate .. Forever;
611 -- Get_Socket_Options and Set_Socket_Options manipulate options associated
612 -- with a socket. Options may exist at multiple protocol levels in the
613 -- communication stack. Socket_Level is the uppermost socket level.
617 IP_Protocol_For_IP_Level,
618 IP_Protocol_For_UDP_Level,
619 IP_Protocol_For_TCP_Level);
621 -- There are several options available to manipulate sockets. Each option
622 -- has a name and several values available. Most of the time, the value is
623 -- a boolean to enable or disable this option.
625 type Option_Name is (
626 Keep_Alive, -- Enable sending of keep-alive messages
627 Reuse_Address, -- Allow bind to reuse local address
628 Broadcast, -- Enable datagram sockets to recv/send broadcasts
629 Send_Buffer, -- Set/get the maximum socket send buffer in bytes
630 Receive_Buffer, -- Set/get the maximum socket recv buffer in bytes
631 Linger, -- Shutdown wait for msg to be sent or timeout occur
632 Error, -- Get and clear the pending socket error
633 No_Delay, -- Do not delay send to coalesce packets (TCP_NODELAY)
634 Add_Membership, -- Join a multicast group
635 Drop_Membership, -- Leave a multicast group
636 Multicast_If, -- Set default outgoing interface for multicast packets
637 Multicast_TTL, -- Indicate the time-to-live of sent multicast packets
638 Multicast_Loop, -- Sent multicast packets are looped to local socket
639 Send_Timeout, -- Set timeout value for output
640 Receive_Timeout); -- Set timeout value for input
642 type Option_Type (Name : Option_Name := Keep_Alive) is record
666 when Add_Membership |
668 Multicast_Address : Inet_Addr_Type;
669 Local_Interface : Inet_Addr_Type;
672 Outgoing_If : Inet_Addr_Type;
674 when Multicast_TTL =>
675 Time_To_Live : Natural;
679 Timeout : Timeval_Duration;
684 -- There are several controls available to manipulate sockets. Each option
685 -- has a name and several values available. These controls differ from the
686 -- socket options in that they are not specific to sockets but are
687 -- available for any device.
689 type Request_Name is (
690 Non_Blocking_IO, -- Cause a caller not to wait on blocking operations.
691 N_Bytes_To_Read); -- Return the number of bytes available to read
693 type Request_Type (Name : Request_Name := Non_Blocking_IO) is record
695 when Non_Blocking_IO =>
698 when N_Bytes_To_Read =>
704 -- A request flag allows to specify the type of message transmissions or
705 -- receptions. A request flag can be combination of zero or more
706 -- predefined request flags.
708 type Request_Flag_Type is private;
710 No_Request_Flag : constant Request_Flag_Type;
711 -- This flag corresponds to the normal execution of an operation
713 Process_Out_Of_Band_Data : constant Request_Flag_Type;
714 -- This flag requests that the receive or send function operates on
715 -- out-of-band data when the socket supports this notion (e.g.
718 Peek_At_Incoming_Data : constant Request_Flag_Type;
719 -- This flag causes the receive operation to return data from the
720 -- beginning of the receive queue without removing that data from the
721 -- queue. A subsequent receive call will return the same data.
723 Wait_For_A_Full_Reception : constant Request_Flag_Type;
724 -- This flag requests that the operation block until the full request is
725 -- satisfied. However, the call may still return less data than requested
726 -- if a signal is caught, an error or disconnect occurs, or the next data
727 -- to be received is of a different type than that returned. Note that
728 -- this flag depends on support in the underlying sockets implementation,
729 -- and is not supported under Windows.
731 Send_End_Of_Record : constant Request_Flag_Type;
732 -- This flag indicates that the entire message has been sent and so this
733 -- terminates the record.
735 function "+" (L, R : Request_Flag_Type) return Request_Flag_Type;
736 -- Combine flag L with flag R
738 type Stream_Element_Reference is access all Ada.Streams.Stream_Element;
740 type Vector_Element is record
741 Base : Stream_Element_Reference;
742 Length : Ada.Streams.Stream_Element_Count;
745 type Vector_Type is array (Integer range <>) of Vector_Element;
747 procedure Create_Socket
748 (Socket : out Socket_Type;
749 Family : Family_Type := Family_Inet;
750 Mode : Mode_Type := Socket_Stream);
751 -- Create an endpoint for communication. Raises Socket_Error on error
753 procedure Accept_Socket
754 (Server : Socket_Type;
755 Socket : out Socket_Type;
756 Address : out Sock_Addr_Type);
757 -- Extracts the first connection request on the queue of pending
758 -- connections, creates a new connected socket with mostly the same
759 -- properties as Server, and allocates a new socket. The returned Address
760 -- is filled in with the address of the connection. Raises Socket_Error on
763 procedure Bind_Socket
764 (Socket : Socket_Type;
765 Address : Sock_Addr_Type);
766 -- Once a socket is created, assign a local address to it. Raise
767 -- Socket_Error on error.
769 procedure Close_Socket (Socket : Socket_Type);
770 -- Close a socket and more specifically a non-connected socket
772 procedure Connect_Socket
773 (Socket : Socket_Type;
774 Server : in out Sock_Addr_Type);
775 -- Make a connection to another socket which has the address of
776 -- Server. Raises Socket_Error on error.
778 procedure Control_Socket
779 (Socket : Socket_Type;
780 Request : in out Request_Type);
781 -- Obtain or set parameter values that control the socket. This control
782 -- differs from the socket options in that they are not specific to
783 -- sockets but are available for any device.
785 function Get_Peer_Name (Socket : Socket_Type) return Sock_Addr_Type;
786 -- Return the peer or remote socket address of a socket. Raise
787 -- Socket_Error on error.
789 function Get_Socket_Name (Socket : Socket_Type) return Sock_Addr_Type;
790 -- Return the local or current socket address of a socket. Return
791 -- No_Sock_Addr on error (for instance, socket closed or not locally
794 function Get_Socket_Option
795 (Socket : Socket_Type;
796 Level : Level_Type := Socket_Level;
797 Name : Option_Name) return Option_Type;
798 -- Get the options associated with a socket. Raises Socket_Error
801 procedure Listen_Socket
802 (Socket : Socket_Type;
803 Length : Positive := 15);
804 -- To accept connections, a socket is first created with Create_Socket,
805 -- a willingness to accept incoming connections and a queue Length for
806 -- incoming connections are specified. Raise Socket_Error on error.
808 procedure Receive_Socket
809 (Socket : Socket_Type;
810 Item : out Ada.Streams.Stream_Element_Array;
811 Last : out Ada.Streams.Stream_Element_Offset;
812 Flags : Request_Flag_Type := No_Request_Flag);
813 -- Receive message from Socket. Last is the index value such that Item
814 -- (Last) is the last character assigned. Note that Last is set to
815 -- Item'First - 1 when the socket has been closed by peer. This is not an
816 -- error and no exception is raised. Flags allows to control the
817 -- reception. Raise Socket_Error on error.
819 procedure Receive_Socket
820 (Socket : Socket_Type;
821 Item : out Ada.Streams.Stream_Element_Array;
822 Last : out Ada.Streams.Stream_Element_Offset;
823 From : out Sock_Addr_Type;
824 Flags : Request_Flag_Type := No_Request_Flag);
825 -- Receive message from Socket. If Socket is not connection-oriented, the
826 -- source address From of the message is filled in. Last is the index
827 -- value such that Item (Last) is the last character assigned. Flags
828 -- allows to control the reception. Raises Socket_Error on error.
830 procedure Receive_Vector
831 (Socket : Socket_Type;
832 Vector : Vector_Type;
833 Count : out Ada.Streams.Stream_Element_Count);
834 -- Receive data from a socket and scatter it into the set of vector
835 -- elements Vector. Count is set to the count of received stream elements.
837 function Resolve_Exception
838 (Occurrence : Ada.Exceptions.Exception_Occurrence) return Error_Type;
839 -- When Socket_Error or Host_Error are raised, the exception message
840 -- contains the error code between brackets and a string describing the
841 -- error code. Resolve_Error extracts the error code from an exception
842 -- message and translate it into an enumeration value.
844 procedure Send_Socket
845 (Socket : Socket_Type;
846 Item : Ada.Streams.Stream_Element_Array;
847 Last : out Ada.Streams.Stream_Element_Offset;
848 Flags : Request_Flag_Type := No_Request_Flag);
849 -- Transmit a message to another socket. Note that Last is set to
850 -- Item'First-1 when socket has been closed by peer. This is not
851 -- considered an error and no exception is raised. Flags allows to control
852 -- the transmission. Raises Socket_Error on any other error condition.
854 procedure Send_Socket
855 (Socket : Socket_Type;
856 Item : Ada.Streams.Stream_Element_Array;
857 Last : out Ada.Streams.Stream_Element_Offset;
859 Flags : Request_Flag_Type := No_Request_Flag);
860 -- Transmit a message to another socket. The address is given by To. Flags
861 -- allows to control the transmission. Raises Socket_Error on error.
863 procedure Send_Vector
864 (Socket : Socket_Type;
865 Vector : Vector_Type;
866 Count : out Ada.Streams.Stream_Element_Count);
867 -- Transmit data gathered from the set of vector elements Vector to a
868 -- socket. Count is set to the count of transmitted stream elements.
870 procedure Set_Socket_Option
871 (Socket : Socket_Type;
872 Level : Level_Type := Socket_Level;
873 Option : Option_Type);
874 -- Manipulate socket options. Raises Socket_Error on error
876 procedure Shutdown_Socket
877 (Socket : Socket_Type;
878 How : Shutmode_Type := Shut_Read_Write);
879 -- Shutdown a connected socket. If How is Shut_Read, further receives will
880 -- be disallowed. If How is Shut_Write, further sends will be disallowed.
881 -- If how is Shut_Read_Write, further sends and receives will be
884 type Stream_Access is access all Ada.Streams.Root_Stream_Type'Class;
885 -- Same interface as Ada.Streams.Stream_IO
887 function Stream (Socket : Socket_Type) return Stream_Access;
888 -- Create a stream associated with a stream-based socket that is
889 -- already connected.
892 (Socket : Socket_Type;
893 Send_To : Sock_Addr_Type) return Stream_Access;
894 -- Create a stream associated with a datagram-based socket that is already
895 -- bound. Send_To is the socket address to which messages are being sent.
897 function Get_Address (Stream : Stream_Access) return Sock_Addr_Type;
898 -- Return the socket address from which the last message was received
900 procedure Free is new Ada.Unchecked_Deallocation
901 (Ada.Streams.Root_Stream_Type'Class, Stream_Access);
902 -- Destroy a stream created by one of the Stream functions above,
903 -- releasing the corresponding resources. The user is responsible for
904 -- calling this subprogram when the stream is not needed anymore.
906 type Socket_Set_Type is limited private;
907 -- This type allows to manipulate sets of sockets. It allows to wait for
908 -- events on multiple endpoints at one time. This is an access type on a
909 -- system dependent structure. To avoid memory leaks it is highly
910 -- recommended to clean the access value with procedure Empty.
912 procedure Clear (Item : in out Socket_Set_Type; Socket : Socket_Type);
913 -- Remove Socket from Item
915 procedure Copy (Source : Socket_Set_Type; Target : in out Socket_Set_Type);
916 -- Copy Source into Target as Socket_Set_Type is limited private
918 procedure Empty (Item : in out Socket_Set_Type);
919 -- Remove all Sockets from Item and deallocate internal data
921 procedure Get (Item : in out Socket_Set_Type; Socket : out Socket_Type);
922 -- Extract a Socket from socket set Item. Socket is set to
923 -- No_Socket when the set is empty.
925 function Is_Empty (Item : Socket_Set_Type) return Boolean;
926 -- Return True iff Item is empty
929 (Item : Socket_Set_Type;
930 Socket : Socket_Type) return Boolean;
931 -- Return True iff Socket is present in Item
933 procedure Set (Item : in out Socket_Set_Type; Socket : Socket_Type);
934 -- Insert Socket into Item
936 -- The select(2) system call waits for events to occur on any of a set of
937 -- file descriptors. Usually, three independent sets of descriptors are
938 -- watched (read, write and exception). A timeout gives an upper bound
939 -- on the amount of time elapsed before select returns. This function
940 -- blocks until an event occurs. On some platforms, the select(2) system
941 -- can block the full process (not just the calling thread).
943 -- Check_Selector provides the very same behaviour. The only difference is
944 -- that it does not watch for exception events. Note that on some
945 -- platforms it is kept process blocking on purpose. The timeout parameter
946 -- allows the user to have the behaviour he wants. Abort_Selector allows
947 -- to abort safely a Check_Selector that is blocked forever. A special
948 -- file descriptor is opened by Create_Selector and included in each call
949 -- to Check_Selector. Abort_Selector causes an event to occur on this
950 -- descriptor in order to unblock Check_Selector. The user must call
951 -- Close_Selector to discard this special file. A reason to abort a select
952 -- operation is typically to add a socket in one of the socket sets when
953 -- the timeout is set to forever.
955 type Selector_Type is limited private;
956 type Selector_Access is access all Selector_Type;
958 subtype Selector_Duration is Timeval_Duration;
960 procedure Create_Selector (Selector : out Selector_Type);
961 -- Create a new selector
963 procedure Close_Selector (Selector : in out Selector_Type);
964 -- Close Selector and all internal descriptors associated; deallocate any
965 -- associated resources. This subprogram may be called only when there is
966 -- no other task still using Selector (i.e. still executing Check_Selector
967 -- or Abort_Selector on this Selector).
969 type Selector_Status is (Completed, Expired, Aborted);
971 procedure Check_Selector
972 (Selector : in out Selector_Type;
973 R_Socket_Set : in out Socket_Set_Type;
974 W_Socket_Set : in out Socket_Set_Type;
975 Status : out Selector_Status;
976 Timeout : Selector_Duration := Forever);
977 -- Return when one Socket in R_Socket_Set has some data to be read or if
978 -- one Socket in W_Socket_Set is ready to transmit some data. In these
979 -- cases Status is set to Completed and sockets that are ready are set in
980 -- R_Socket_Set or W_Socket_Set. Status is set to Expired if no socket was
981 -- ready after a Timeout expiration. Status is set to Aborted if an abort
982 -- signal has been received while checking socket status.
983 -- Note that two different Socket_Set_Type objects must be passed as
984 -- R_Socket_Set and W_Socket_Set (even if they denote the same set of
985 -- Sockets), or some event may be lost.
986 -- Socket_Error is raised when the select(2) system call returns an
987 -- error condition, or when a read error occurs on the signalling socket
988 -- used for the implementation of Abort_Selector.
990 procedure Check_Selector
991 (Selector : in out Selector_Type;
992 R_Socket_Set : in out Socket_Set_Type;
993 W_Socket_Set : in out Socket_Set_Type;
994 E_Socket_Set : in out Socket_Set_Type;
995 Status : out Selector_Status;
996 Timeout : Selector_Duration := Forever);
997 -- This refined version of Check_Selector allows to watch for exception
998 -- events (that is notifications of out-of-band transmission and
999 -- reception). As above, all of R_Socket_Set, W_Socket_Set and
1000 -- E_Socket_Set must be different objects.
1002 procedure Abort_Selector (Selector : Selector_Type);
1003 -- Send an abort signal to the selector
1007 type Socket_Type is new Integer;
1008 No_Socket : constant Socket_Type := -1;
1010 type Selector_Type is limited record
1011 R_Sig_Socket : Socket_Type := No_Socket;
1012 W_Sig_Socket : Socket_Type := No_Socket;
1015 pragma Volatile (Selector_Type);
1017 -- The two signalling sockets are used to abort a select operation
1019 subtype Socket_Set_Access is System.Address;
1020 No_Socket_Set : constant Socket_Set_Access := System.Null_Address;
1022 type Socket_Set_Type is record
1023 Last : Socket_Type := No_Socket;
1024 Set : Socket_Set_Access := No_Socket_Set;
1027 subtype Inet_Addr_Comp_Type is Natural range 0 .. 255;
1028 -- Octet for Internet address
1030 type Inet_Addr_VN_Type is array (Natural range <>) of Inet_Addr_Comp_Type;
1032 subtype Inet_Addr_V4_Type is Inet_Addr_VN_Type (1 .. 4);
1033 subtype Inet_Addr_V6_Type is Inet_Addr_VN_Type (1 .. 16);
1035 type Inet_Addr_Type (Family : Family_Type := Family_Inet) is record
1038 Sin_V4 : Inet_Addr_V4_Type := (others => 0);
1040 when Family_Inet6 =>
1041 Sin_V6 : Inet_Addr_V6_Type := (others => 0);
1045 Any_Port : constant Port_Type := 0;
1046 No_Port : constant Port_Type := 0;
1048 Any_Inet_Addr : constant Inet_Addr_Type :=
1049 (Family_Inet, (others => 0));
1050 No_Inet_Addr : constant Inet_Addr_Type :=
1051 (Family_Inet, (others => 0));
1052 Broadcast_Inet_Addr : constant Inet_Addr_Type :=
1053 (Family_Inet, (others => 255));
1055 No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
1057 Max_Name_Length : constant := 64;
1058 -- The constant MAXHOSTNAMELEN is usually set to 64
1060 subtype Name_Index is Natural range 1 .. Max_Name_Length;
1063 (Length : Name_Index := Max_Name_Length)
1065 Name : String (1 .. Length);
1067 -- We need fixed strings to avoid access types in host entry type
1069 type Name_Array is array (Natural range <>) of Name_Type;
1070 type Inet_Addr_Array is array (Natural range <>) of Inet_Addr_Type;
1072 type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is record
1073 Official : Name_Type;
1074 Aliases : Name_Array (1 .. Aliases_Length);
1075 Addresses : Inet_Addr_Array (1 .. Addresses_Length);
1078 type Service_Entry_Type (Aliases_Length : Natural) is record
1079 Official : Name_Type;
1080 Aliases : Name_Array (1 .. Aliases_Length);
1082 Protocol : Name_Type;
1085 type Request_Flag_Type is mod 2 ** 8;
1086 No_Request_Flag : constant Request_Flag_Type := 0;
1087 Process_Out_Of_Band_Data : constant Request_Flag_Type := 1;
1088 Peek_At_Incoming_Data : constant Request_Flag_Type := 2;
1089 Wait_For_A_Full_Reception : constant Request_Flag_Type := 4;
1090 Send_End_Of_Record : constant Request_Flag_Type := 8;