1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- G N A T . S O C K E T S --
9 -- Copyright (C) 2001-2008, 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
44 -- The VMS implementation was implemented using the DECC RTL Socket API,
45 -- and is thus subject to limitations in the implementation of this API.
47 -- VxWorks cross ports fully implement this package
49 -- This package is not yet implemented on LynxOS or other cross ports
53 with Ada.Unchecked_Deallocation;
57 with System.OS_Constants;
58 with System.Storage_Elements;
60 package GNAT.Sockets is
62 -- Sockets are designed to provide a consistent communication facility
63 -- between applications. This package provides an Ada binding to the
64 -- the de-facto standard BSD sockets API. The documentation below covers
65 -- only the specific binding provided by this package. It assumes that
66 -- the reader is already familiar with general network programming and
67 -- sockets usage. A useful reference on this matter is W. Richard Stevens'
68 -- "UNIX Network Programming: The Sockets Networking API"
69 -- (ISBN: 0131411551).
71 -- GNAT.Sockets has been designed with several ideas in mind
73 -- This is a system independent interface. Therefore, we try as much as
74 -- possible to mask system incompatibilities. Some functionalities are not
75 -- available because there are not fully supported on some systems.
77 -- This is a thick binding. For instance, a major effort has been done to
78 -- avoid using memory addresses or untyped ints. We preferred to define
79 -- streams and enumeration types. Errors are not returned as returned
80 -- values but as exceptions.
82 -- This package provides a POSIX-compliant interface (between two
83 -- different implementations of the same routine, we adopt the one closest
84 -- to the POSIX specification). For instance, using select(), the
85 -- notification of an asynchronous connect failure is delivered in the
86 -- write socket set (POSIX) instead of the exception socket set (NT).
88 -- The example below demonstrates various features of GNAT.Sockets:
90 -- with GNAT.Sockets; use GNAT.Sockets;
93 -- with Ada.Exceptions; use Ada.Exceptions;
95 -- procedure PingPong is
97 -- Group : constant String := "239.255.128.128";
98 -- -- Multicast group: administratively scoped IP address
106 -- Address : Sock_Addr_Type;
107 -- Server : Socket_Type;
108 -- Socket : Socket_Type;
109 -- Channel : Stream_Access;
114 -- -- Get an Internet address of a host (here the local host name).
115 -- -- Note that a host can have several addresses. Here we get
116 -- -- the first one which is supposed to be the official one.
118 -- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
120 -- -- Get a socket address that is an Internet address and a port
122 -- Address.Port := 5876;
124 -- -- The first step is to create a socket. Once created, this
125 -- -- socket must be associated to with an address. Usually only a
126 -- -- server (Pong here) needs to bind an address explicitly. Most
127 -- -- of the time clients can skip this step because the socket
128 -- -- routines will bind an arbitrary address to an unbound socket.
130 -- Create_Socket (Server);
132 -- -- Allow reuse of local addresses
137 -- (Reuse_Address, True));
139 -- Bind_Socket (Server, Address);
141 -- -- A server marks a socket as willing to receive connect events
143 -- Listen_Socket (Server);
145 -- -- Once a server calls Listen_Socket, incoming connects events
146 -- -- can be accepted. The returned Socket is a new socket that
147 -- -- represents the server side of the connection. Server remains
148 -- -- available to receive further connections.
150 -- Accept_Socket (Server, Socket, Address);
152 -- -- Return a stream associated to the connected socket
154 -- Channel := Stream (Socket);
156 -- -- Force Pong to block
160 -- -- Receive and print message from client Ping
163 -- Message : String := String'Input (Channel);
166 -- Ada.Text_IO.Put_Line (Message);
168 -- -- Send same message back to client Ping
170 -- String'Output (Channel, Message);
173 -- Close_Socket (Server);
174 -- Close_Socket (Socket);
176 -- -- Part of the multicast example
178 -- -- Create a datagram socket to send connectionless, unreliable
179 -- -- messages of a fixed maximum length.
181 -- Create_Socket (Socket, Family_Inet, Socket_Datagram);
183 -- -- Allow reuse of local addresses
188 -- (Reuse_Address, True));
190 -- -- Controls the live time of the datagram to avoid it being
191 -- -- looped forever due to routing errors. Routers decrement
192 -- -- the TTL of every datagram as it traverses from one network
193 -- -- to another and when its value reaches 0 the packet is
194 -- -- dropped. Default is 1.
198 -- IP_Protocol_For_IP_Level,
199 -- (Multicast_TTL, 1));
201 -- -- Want the data you send to be looped back to your host
205 -- IP_Protocol_For_IP_Level,
206 -- (Multicast_Loop, True));
208 -- -- If this socket is intended to receive messages, bind it
209 -- -- to a given socket address.
211 -- Address.Addr := Any_Inet_Addr;
212 -- Address.Port := 55505;
214 -- Bind_Socket (Socket, Address);
216 -- -- Join a multicast group
218 -- -- Portability note: On Windows, this option may be set only
219 -- -- on a bound socket.
223 -- IP_Protocol_For_IP_Level,
224 -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
226 -- -- If this socket is intended to send messages, provide the
227 -- -- receiver socket address.
229 -- Address.Addr := Inet_Addr (Group);
230 -- Address.Port := 55506;
232 -- Channel := Stream (Socket, Address);
234 -- -- Receive and print message from client Ping
237 -- Message : String := String'Input (Channel);
240 -- -- Get the address of the sender
242 -- Address := Get_Address (Channel);
243 -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
245 -- -- Send same message back to client Ping
247 -- String'Output (Channel, Message);
250 -- Close_Socket (Socket);
254 -- exception when E : others =>
255 -- Ada.Text_IO.Put_Line
256 -- (Exception_Name (E) & ": " & Exception_Message (E));
265 -- Address : Sock_Addr_Type;
266 -- Socket : Socket_Type;
267 -- Channel : Stream_Access;
272 -- -- See comments in Ping section for the first steps
274 -- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
275 -- Address.Port := 5876;
276 -- Create_Socket (Socket);
281 -- (Reuse_Address, True));
283 -- -- Force Pong to block
287 -- -- If the client's socket is not bound, Connect_Socket will
288 -- -- bind to an unused address. The client uses Connect_Socket to
289 -- -- create a logical connection between the client's socket and
290 -- -- a server's socket returned by Accept_Socket.
292 -- Connect_Socket (Socket, Address);
294 -- Channel := Stream (Socket);
296 -- -- Send message to server Pong
298 -- String'Output (Channel, "Hello world");
300 -- -- Force Ping to block
304 -- -- Receive and print message from server Pong
306 -- Ada.Text_IO.Put_Line (String'Input (Channel));
307 -- Close_Socket (Socket);
309 -- -- Part of multicast example. Code similar to Pong's one
311 -- Create_Socket (Socket, Family_Inet, Socket_Datagram);
316 -- (Reuse_Address, True));
320 -- IP_Protocol_For_IP_Level,
321 -- (Multicast_TTL, 1));
325 -- IP_Protocol_For_IP_Level,
326 -- (Multicast_Loop, True));
328 -- Address.Addr := Any_Inet_Addr;
329 -- Address.Port := 55506;
331 -- Bind_Socket (Socket, Address);
335 -- IP_Protocol_For_IP_Level,
336 -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
338 -- Address.Addr := Inet_Addr (Group);
339 -- Address.Port := 55505;
341 -- Channel := Stream (Socket, Address);
343 -- -- Send message to server Pong
345 -- String'Output (Channel, "Hello world");
347 -- -- Receive and print message from server Pong
350 -- Message : String := String'Input (Channel);
353 -- Address := Get_Address (Channel);
354 -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
357 -- Close_Socket (Socket);
361 -- exception when E : others =>
362 -- Ada.Text_IO.Put_Line
363 -- (Exception_Name (E) & ": " & Exception_Message (E));
375 package SOSC renames System.OS_Constants;
376 -- Renaming used to provide short-hand notations throughout the sockets
377 -- binding. Note that System.OS_Constants is an internal unit, and the
378 -- entities declared therein are not meant for direct access by users,
379 -- including through this renaming.
381 procedure Initialize;
383 (Entity => Initialize,
384 Message => "explicit initialization is no longer required");
385 -- Initialize must be called before using any other socket routines.
386 -- Note that this operation is a no-op on UNIX platforms, but applications
387 -- should make sure to call it if portability is expected: some platforms
388 -- (such as Windows) require initialization before any socket operation.
389 -- This is now a no-op (initialization and finalization are done
392 procedure Initialize (Process_Blocking_IO : Boolean);
394 (Entity => Initialize,
395 Message => "passing a parameter to Initialize is no longer supported");
396 -- Previous versions of GNAT.Sockets used to require the user to indicate
397 -- whether socket I/O was process- or thread-blocking on the platform.
398 -- This property is now determined automatically when the run-time library
399 -- is built. The old version of Initialize, taking a parameter, is kept
400 -- for compatibility reasons, but this interface is obsolete (and if the
401 -- value given is wrong, an exception will be raised at run time).
402 -- This is now a no-op (initialization and finalization are done
408 Message => "explicit finalization is no longer required");
409 -- After Finalize is called it is not possible to use any routines
410 -- exported in by this package. This procedure is idempotent.
411 -- This is now a no-op (initialization and finalization are done
414 type Socket_Type is private;
415 -- Sockets are used to implement a reliable bi-directional point-to-point,
416 -- stream-based connections between hosts. No_Socket provides a special
417 -- value to denote uninitialized sockets.
419 No_Socket : constant Socket_Type;
421 type Selector_Type is limited private;
422 type Selector_Access is access all Selector_Type;
423 -- Selector objects are used to wait for i/o events to occur on sockets
425 -- Timeval_Duration is a subtype of Standard.Duration because the full
426 -- range of Standard.Duration cannot be represented in the equivalent C
427 -- structure. Moreover, negative values are not allowed to avoid system
428 -- incompatibilities.
430 Immediate : constant Duration := 0.0;
432 Timeval_Forever : constant := 2.0 ** (SOSC.SIZEOF_tv_sec * 8 - 1) - 1.0;
433 Forever : constant Duration :=
434 Duration'Min (Duration'Last, Timeval_Forever);
436 subtype Timeval_Duration is Duration range Immediate .. Forever;
438 subtype Selector_Duration is Timeval_Duration;
439 -- Timeout value for selector operations
441 type Selector_Status is (Completed, Expired, Aborted);
442 -- Completion status of a selector operation, indicated as follows:
443 -- Complete: one of the expected events occurred
444 -- Expired: no event occurred before the expiration of the timeout
445 -- Aborted: an external action cancelled the wait operation before
446 -- any event occurred.
448 Socket_Error : exception;
449 -- There is only one exception in this package to deal with an error during
450 -- a socket routine. Once raised, its message contains a string describing
453 function Image (Socket : Socket_Type) return String;
454 -- Return a printable string for Socket
456 function To_C (Socket : Socket_Type) return Integer;
457 -- Return a file descriptor to be used by external subprograms. This is
458 -- useful for C functions that are not yet interfaced in this package.
460 type Family_Type is (Family_Inet, Family_Inet6);
461 -- Address family (or protocol family) identifies the communication domain
462 -- and groups protocols with similar address formats. IPv6 will soon be
465 type Mode_Type is (Socket_Stream, Socket_Datagram);
466 -- Stream sockets provide connection-oriented byte streams. Datagram
467 -- sockets support unreliable connectionless message based communication.
469 type Shutmode_Type is (Shut_Read, Shut_Write, Shut_Read_Write);
470 -- When a process closes a socket, the policy is to retain any data queued
471 -- until either a delivery or a timeout expiration (in this case, the data
472 -- are discarded). A finer control is available through shutdown. With
473 -- Shut_Read, no more data can be received from the socket. With_Write, no
474 -- more data can be transmitted. Neither transmission nor reception can be
475 -- performed with Shut_Read_Write.
477 type Port_Type is new Natural;
478 -- Classical port definition. No_Port provides a special value to
479 -- denote uninitialized port. Any_Port provides a special value
480 -- enabling all ports.
482 Any_Port : constant Port_Type;
483 No_Port : constant Port_Type;
485 type Inet_Addr_Type (Family : Family_Type := Family_Inet) is private;
486 -- An Internet address depends on an address family (IPv4 contains 4 octets
487 -- and IPv6 contains 16 octets). Any_Inet_Addr is a special value treated
488 -- like a wildcard enabling all addresses. No_Inet_Addr provides a special
489 -- value to denote uninitialized inet addresses.
491 Any_Inet_Addr : constant Inet_Addr_Type;
492 No_Inet_Addr : constant Inet_Addr_Type;
493 Broadcast_Inet_Addr : constant Inet_Addr_Type;
495 type Sock_Addr_Type (Family : Family_Type := Family_Inet) is record
496 Addr : Inet_Addr_Type (Family);
499 -- Socket addresses fully define a socket connection with protocol family,
500 -- an Internet address and a port. No_Sock_Addr provides a special value
501 -- for uninitialized socket addresses.
503 No_Sock_Addr : constant Sock_Addr_Type;
505 function Image (Value : Inet_Addr_Type) return String;
506 -- Return an image of an Internet address. IPv4 notation consists in 4
507 -- octets in decimal format separated by dots. IPv6 notation consists in
508 -- 16 octets in hexadecimal format separated by colons (and possibly
511 function Image (Value : Sock_Addr_Type) return String;
512 -- Return inet address image and port image separated by a colon
514 function Inet_Addr (Image : String) return Inet_Addr_Type;
515 -- Convert address image from numbers-and-dots notation into an
518 -- Host entries provide complete information on a given host: the official
519 -- name, an array of alternative names or aliases and array of network
523 (Aliases_Length, Addresses_Length : Natural) is private;
525 function Official_Name (E : Host_Entry_Type) return String;
526 -- Return official name in host entry
528 function Aliases_Length (E : Host_Entry_Type) return Natural;
529 -- Return number of aliases in host entry
531 function Addresses_Length (E : Host_Entry_Type) return Natural;
532 -- Return number of addresses in host entry
535 (E : Host_Entry_Type;
536 N : Positive := 1) return String;
537 -- Return N'th aliases in host entry. The first index is 1
540 (E : Host_Entry_Type;
541 N : Positive := 1) return Inet_Addr_Type;
542 -- Return N'th addresses in host entry. The first index is 1
544 Host_Error : exception;
545 -- Exception raised by the two following procedures. Once raised, its
546 -- message contains a string describing the error code. This exception is
547 -- raised when an host entry cannot be retrieved.
549 function Get_Host_By_Address
550 (Address : Inet_Addr_Type;
551 Family : Family_Type := Family_Inet) return Host_Entry_Type;
552 -- Return host entry structure for the given Inet address. Note that no
553 -- result will be returned if there is no mapping of this IP address to a
554 -- host name in the system tables (host database, DNS or otherwise).
556 function Get_Host_By_Name
557 (Name : String) return Host_Entry_Type;
558 -- Return host entry structure for the given host name. Here name is
559 -- either a host name, or an IP address. If Name is an IP address, this
560 -- is equivalent to Get_Host_By_Address (Inet_Addr (Name)).
562 function Host_Name return String;
563 -- Return the name of the current host
565 type Service_Entry_Type (Aliases_Length : Natural) is private;
566 -- Service entries provide complete information on a given service: the
567 -- official name, an array of alternative names or aliases and the port
570 function Official_Name (S : Service_Entry_Type) return String;
571 -- Return official name in service entry
573 function Port_Number (S : Service_Entry_Type) return Port_Type;
574 -- Return port number in service entry
576 function Protocol_Name (S : Service_Entry_Type) return String;
577 -- Return Protocol in service entry (usually UDP or TCP)
579 function Aliases_Length (S : Service_Entry_Type) return Natural;
580 -- Return number of aliases in service entry
583 (S : Service_Entry_Type;
584 N : Positive := 1) return String;
585 -- Return N'th aliases in service entry (the first index is 1)
587 function Get_Service_By_Name
589 Protocol : String) return Service_Entry_Type;
590 -- Return service entry structure for the given service name
592 function Get_Service_By_Port
594 Protocol : String) return Service_Entry_Type;
595 -- Return service entry structure for the given service port number
597 Service_Error : exception;
598 -- Comment required ???
600 -- Errors are described by an enumeration type. There is only one exception
601 -- Socket_Error in this package to deal with an error during a socket
602 -- routine. Once raised, its message contains the error code between
603 -- brackets and a string describing the error code.
605 -- The name of the enumeration constant documents the error condition
606 -- Note that on some platforms, a single error value is used for both
607 -- EWOULDBLOCK and EAGAIN. Both errors are therefore always reported as
608 -- Resource_Temporarily_Unavailable.
613 Address_Already_In_Use,
614 Cannot_Assign_Requested_Address,
615 Address_Family_Not_Supported_By_Protocol,
616 Operation_Already_In_Progress,
618 Software_Caused_Connection_Abort,
620 Connection_Reset_By_Peer,
621 Destination_Address_Required,
625 Operation_Now_In_Progress,
626 Interrupted_System_Call,
629 Transport_Endpoint_Already_Connected,
630 Too_Many_Symbolic_Links,
635 Network_Dropped_Connection_Because_Of_Reset,
636 Network_Is_Unreachable,
637 No_Buffer_Space_Available,
638 Protocol_Not_Available,
639 Transport_Endpoint_Not_Connected,
640 Socket_Operation_On_Non_Socket,
641 Operation_Not_Supported,
642 Protocol_Family_Not_Supported,
643 Protocol_Not_Supported,
644 Protocol_Wrong_Type_For_Socket,
645 Cannot_Send_After_Transport_Endpoint_Shutdown,
646 Socket_Type_Not_Supported,
647 Connection_Timed_Out,
649 Resource_Temporarily_Unavailable,
652 Host_Name_Lookup_Failure,
653 Non_Recoverable_Error,
654 Unknown_Server_Error,
655 Cannot_Resolve_Error);
657 -- Get_Socket_Options and Set_Socket_Options manipulate options associated
658 -- with a socket. Options may exist at multiple protocol levels in the
659 -- communication stack. Socket_Level is the uppermost socket level.
663 IP_Protocol_For_IP_Level,
664 IP_Protocol_For_UDP_Level,
665 IP_Protocol_For_TCP_Level);
667 -- There are several options available to manipulate sockets. Each option
668 -- has a name and several values available. Most of the time, the value is
669 -- a boolean to enable or disable this option.
671 type Option_Name is (
672 Keep_Alive, -- Enable sending of keep-alive messages
673 Reuse_Address, -- Allow bind to reuse local address
674 Broadcast, -- Enable datagram sockets to recv/send broadcasts
675 Send_Buffer, -- Set/get the maximum socket send buffer in bytes
676 Receive_Buffer, -- Set/get the maximum socket recv buffer in bytes
677 Linger, -- Shutdown wait for msg to be sent or timeout occur
678 Error, -- Get and clear the pending socket error
679 No_Delay, -- Do not delay send to coalesce data (TCP_NODELAY)
680 Add_Membership, -- Join a multicast group
681 Drop_Membership, -- Leave a multicast group
682 Multicast_If, -- Set default out interface for multicast packets
683 Multicast_TTL, -- Set the time-to-live of sent multicast packets
684 Multicast_Loop, -- Sent multicast packets are looped to local socket
685 Receive_Packet_Info, -- Receive low level packet info as ancillary data
686 Send_Timeout, -- Set timeout value for output
687 Receive_Timeout); -- Set timeout value for input
689 type Option_Type (Name : Option_Name := Keep_Alive) is record
696 Receive_Packet_Info |
714 when Add_Membership |
716 Multicast_Address : Inet_Addr_Type;
717 Local_Interface : Inet_Addr_Type;
720 Outgoing_If : Inet_Addr_Type;
722 when Multicast_TTL =>
723 Time_To_Live : Natural;
727 Timeout : Timeval_Duration;
732 -- There are several controls available to manipulate sockets. Each option
733 -- has a name and several values available. These controls differ from the
734 -- socket options in that they are not specific to sockets but are
735 -- available for any device.
737 type Request_Name is (
738 Non_Blocking_IO, -- Cause a caller not to wait on blocking operations.
739 N_Bytes_To_Read); -- Return the number of bytes available to read
741 type Request_Type (Name : Request_Name := Non_Blocking_IO) is record
743 when Non_Blocking_IO =>
746 when N_Bytes_To_Read =>
752 -- A request flag allows to specify the type of message transmissions or
753 -- receptions. A request flag can be combination of zero or more
754 -- predefined request flags.
756 type Request_Flag_Type is private;
758 No_Request_Flag : constant Request_Flag_Type;
759 -- This flag corresponds to the normal execution of an operation
761 Process_Out_Of_Band_Data : constant Request_Flag_Type;
762 -- This flag requests that the receive or send function operates on
763 -- out-of-band data when the socket supports this notion (e.g.
766 Peek_At_Incoming_Data : constant Request_Flag_Type;
767 -- This flag causes the receive operation to return data from the beginning
768 -- of the receive queue without removing that data from the queue. A
769 -- subsequent receive call will return the same data.
771 Wait_For_A_Full_Reception : constant Request_Flag_Type;
772 -- This flag requests that the operation block until the full request is
773 -- satisfied. However, the call may still return less data than requested
774 -- if a signal is caught, an error or disconnect occurs, or the next data
775 -- to be received is of a different type than that returned. Note that
776 -- this flag depends on support in the underlying sockets implementation,
777 -- and is not supported under Windows.
779 Send_End_Of_Record : constant Request_Flag_Type;
780 -- This flag indicates that the entire message has been sent and so this
781 -- terminates the record.
783 function "+" (L, R : Request_Flag_Type) return Request_Flag_Type;
784 -- Combine flag L with flag R
786 type Stream_Element_Reference is access all Ada.Streams.Stream_Element;
788 type Vector_Element is record
789 Base : Stream_Element_Reference;
790 Length : Ada.Streams.Stream_Element_Count;
793 type Vector_Type is array (Integer range <>) of Vector_Element;
795 procedure Create_Socket
796 (Socket : out Socket_Type;
797 Family : Family_Type := Family_Inet;
798 Mode : Mode_Type := Socket_Stream);
799 -- Create an endpoint for communication. Raises Socket_Error on error
801 procedure Accept_Socket
802 (Server : Socket_Type;
803 Socket : out Socket_Type;
804 Address : out Sock_Addr_Type);
805 -- Extracts the first connection request on the queue of pending
806 -- connections, creates a new connected socket with mostly the same
807 -- properties as Server, and allocates a new socket. The returned Address
808 -- is filled in with the address of the connection. Raises Socket_Error on
811 procedure Accept_Socket
812 (Server : Socket_Type;
813 Socket : out Socket_Type;
814 Address : out Sock_Addr_Type;
815 Timeout : Selector_Duration;
816 Selector : access Selector_Type := null;
817 Status : out Selector_Status);
818 -- Accept a new connection on Server using Accept_Socket, waiting no longer
819 -- than the given timeout duration. Status is set to indicate whether the
820 -- operation completed successfully, timed out, or was aborted. If Selector
821 -- is not null, the designated selector is used to wait for the socket to
822 -- become available, else a private selector object is created by this
823 -- procedure and destroyed before it returns.
825 procedure Bind_Socket
826 (Socket : Socket_Type;
827 Address : Sock_Addr_Type);
828 -- Once a socket is created, assign a local address to it. Raise
829 -- Socket_Error on error.
831 procedure Close_Socket (Socket : Socket_Type);
832 -- Close a socket and more specifically a non-connected socket
834 procedure Connect_Socket
835 (Socket : Socket_Type;
836 Server : Sock_Addr_Type);
837 -- Make a connection to another socket which has the address of Server.
838 -- Raises Socket_Error on error.
840 procedure Connect_Socket
841 (Socket : Socket_Type;
842 Server : Sock_Addr_Type;
843 Timeout : Selector_Duration;
844 Selector : access Selector_Type := null;
845 Status : out Selector_Status);
846 -- Connect Socket to the given Server address using Connect_Socket, waiting
847 -- no longer than the given timeout duration. Status is set to indicate
848 -- whether the operation completed successfully, timed out, or was aborted.
849 -- If Selector is not null, the designated selector is used to wait for the
850 -- socket to become available, else a private selector object is created
851 -- by this procedure and destroyed before it returns.
853 procedure Control_Socket
854 (Socket : Socket_Type;
855 Request : in out Request_Type);
856 -- Obtain or set parameter values that control the socket. This control
857 -- differs from the socket options in that they are not specific to sockets
858 -- but are available for any device.
860 function Get_Peer_Name (Socket : Socket_Type) return Sock_Addr_Type;
861 -- Return the peer or remote socket address of a socket. Raise
862 -- Socket_Error on error.
864 function Get_Socket_Name (Socket : Socket_Type) return Sock_Addr_Type;
865 -- Return the local or current socket address of a socket. Return
866 -- No_Sock_Addr on error (e.g. socket closed or not locally bound).
868 function Get_Socket_Option
869 (Socket : Socket_Type;
870 Level : Level_Type := Socket_Level;
871 Name : Option_Name) return Option_Type;
872 -- Get the options associated with a socket. Raises Socket_Error on error
874 procedure Listen_Socket
875 (Socket : Socket_Type;
876 Length : Natural := 15);
877 -- To accept connections, a socket is first created with Create_Socket,
878 -- a willingness to accept incoming connections and a queue Length for
879 -- incoming connections are specified. Raise Socket_Error on error.
880 -- The queue length of 15 is an example value that should be appropriate
881 -- in usual cases. It can be adjusted according to each application's
882 -- particular requirements.
884 procedure Receive_Socket
885 (Socket : Socket_Type;
886 Item : out Ada.Streams.Stream_Element_Array;
887 Last : out Ada.Streams.Stream_Element_Offset;
888 Flags : Request_Flag_Type := No_Request_Flag);
889 -- Receive message from Socket. Last is the index value such that Item
890 -- (Last) is the last character assigned. Note that Last is set to
891 -- Item'First - 1 when the socket has been closed by peer. This is not an
892 -- error and no exception is raised. Flags allows to control the
893 -- reception. Raise Socket_Error on error.
895 procedure Receive_Socket
896 (Socket : Socket_Type;
897 Item : out Ada.Streams.Stream_Element_Array;
898 Last : out Ada.Streams.Stream_Element_Offset;
899 From : out Sock_Addr_Type;
900 Flags : Request_Flag_Type := No_Request_Flag);
901 -- Receive message from Socket. If Socket is not connection-oriented, the
902 -- source address From of the message is filled in. Last is the index
903 -- value such that Item (Last) is the last character assigned. Flags
904 -- allows to control the reception. Raises Socket_Error on error.
906 procedure Receive_Vector
907 (Socket : Socket_Type;
908 Vector : Vector_Type;
909 Count : out Ada.Streams.Stream_Element_Count);
910 -- Receive data from a socket and scatter it into the set of vector
911 -- elements Vector. Count is set to the count of received stream elements.
913 function Resolve_Exception
914 (Occurrence : Ada.Exceptions.Exception_Occurrence) return Error_Type;
915 -- When Socket_Error or Host_Error are raised, the exception message
916 -- contains the error code between brackets and a string describing the
917 -- error code. Resolve_Error extracts the error code from an exception
918 -- message and translate it into an enumeration value.
920 procedure Send_Socket
921 (Socket : Socket_Type;
922 Item : Ada.Streams.Stream_Element_Array;
923 Last : out Ada.Streams.Stream_Element_Offset;
924 To : access Sock_Addr_Type;
925 Flags : Request_Flag_Type := No_Request_Flag);
926 pragma Inline (Send_Socket);
927 -- Transmit a message over a socket. For a datagram socket, the address is
928 -- given by To.all. For a stream socket, To must be null. Flags
929 -- allows to control the transmission. Raises Socket_Error on error.
930 -- Note: this subprogram is inlined because it is also used to implement
931 -- the two variants below.
933 procedure Send_Socket
934 (Socket : Socket_Type;
935 Item : Ada.Streams.Stream_Element_Array;
936 Last : out Ada.Streams.Stream_Element_Offset;
937 Flags : Request_Flag_Type := No_Request_Flag);
938 -- Transmit a message over a socket. Upon return, Last is set to the index
939 -- within Item of the last element transmitted. Flags allows to control
940 -- the transmission. Raises Socket_Error on any detected error condition.
942 procedure Send_Socket
943 (Socket : Socket_Type;
944 Item : Ada.Streams.Stream_Element_Array;
945 Last : out Ada.Streams.Stream_Element_Offset;
947 Flags : Request_Flag_Type := No_Request_Flag);
948 -- Transmit a message over a datagram socket. The destination address is
949 -- To. Flags allows to control the transmission. Raises Socket_Error on
952 procedure Send_Vector
953 (Socket : Socket_Type;
954 Vector : Vector_Type;
955 Count : out Ada.Streams.Stream_Element_Count);
956 -- Transmit data gathered from the set of vector elements Vector to a
957 -- socket. Count is set to the count of transmitted stream elements.
959 procedure Set_Socket_Option
960 (Socket : Socket_Type;
961 Level : Level_Type := Socket_Level;
962 Option : Option_Type);
963 -- Manipulate socket options. Raises Socket_Error on error
965 procedure Shutdown_Socket
966 (Socket : Socket_Type;
967 How : Shutmode_Type := Shut_Read_Write);
968 -- Shutdown a connected socket. If How is Shut_Read, further receives will
969 -- be disallowed. If How is Shut_Write, further sends will be disallowed.
970 -- If how is Shut_Read_Write, further sends and receives will be
973 type Stream_Access is access all Ada.Streams.Root_Stream_Type'Class;
974 -- Same interface as Ada.Streams.Stream_IO
976 function Stream (Socket : Socket_Type) return Stream_Access;
977 -- Create a stream associated with an already connected stream-based socket
980 (Socket : Socket_Type;
981 Send_To : Sock_Addr_Type) return Stream_Access;
982 -- Create a stream associated with an already bound datagram-based socket.
983 -- Send_To is the destination address to which messages are being sent.
986 (Stream : not null Stream_Access) return Sock_Addr_Type;
987 -- Return the socket address from which the last message was received
989 procedure Free is new Ada.Unchecked_Deallocation
990 (Ada.Streams.Root_Stream_Type'Class, Stream_Access);
991 -- Destroy a stream created by one of the Stream functions above,
992 -- releasing the corresponding resources. The user is responsible for
993 -- calling this subprogram when the stream is not needed anymore.
995 type Socket_Set_Type is limited private;
996 -- This type allows to manipulate sets of sockets. It allows to wait for
997 -- events on multiple endpoints at one time.
998 -- Note: This type used to contain a pointer to dynamically allocated
999 -- storage, but this is not the case anymore, and no special precautions
1000 -- are required to avoid memory leaks.
1002 procedure Clear (Item : in out Socket_Set_Type; Socket : Socket_Type);
1003 -- Remove Socket from Item
1005 procedure Copy (Source : Socket_Set_Type; Target : in out Socket_Set_Type);
1006 -- Copy Source into Target as Socket_Set_Type is limited private
1008 procedure Empty (Item : in out Socket_Set_Type);
1009 -- Remove all Sockets from Item
1011 procedure Get (Item : in out Socket_Set_Type; Socket : out Socket_Type);
1012 -- Extract a Socket from socket set Item. Socket is set to
1013 -- No_Socket when the set is empty.
1015 function Is_Empty (Item : Socket_Set_Type) return Boolean;
1016 -- Return True iff Item is empty
1019 (Item : Socket_Set_Type;
1020 Socket : Socket_Type) return Boolean;
1021 -- Return True iff Socket is present in Item
1023 procedure Set (Item : in out Socket_Set_Type; Socket : Socket_Type);
1024 -- Insert Socket into Item
1026 function Image (Item : Socket_Set_Type) return String;
1027 -- Return a printable image of Item, for debugging purposes
1029 -- The select(2) system call waits for events to occur on any of a set of
1030 -- file descriptors. Usually, three independent sets of descriptors are
1031 -- watched (read, write and exception). A timeout gives an upper bound
1032 -- on the amount of time elapsed before select returns. This function
1033 -- blocks until an event occurs. On some platforms, the select(2) system
1034 -- can block the full process (not just the calling thread).
1036 -- Check_Selector provides the very same behaviour. The only difference is
1037 -- that it does not watch for exception events. Note that on some
1038 -- platforms it is kept process blocking on purpose. The timeout parameter
1039 -- allows the user to have the behaviour he wants. Abort_Selector allows
1040 -- to safely abort a blocked Check_Selector call. A special socket
1041 -- is opened by Create_Selector and included in each call to
1042 -- Check_Selector. Abort_Selector causes an event to occur on this
1043 -- descriptor in order to unblock Check_Selector. Note that each call to
1044 -- Abort_Selector will cause exactly one call to Check_Selector to return
1045 -- with Aborted status. The special socket created by Create_Selector is
1046 -- closed when Close_Selector is called.
1047 -- A typical case where it is useful to abort a Check_Selector operation is
1048 -- the situation where a change to the monitored sockets set must be made.
1050 procedure Create_Selector (Selector : out Selector_Type);
1051 -- Create a new selector
1053 procedure Close_Selector (Selector : in out Selector_Type);
1054 -- Close Selector and all internal descriptors associated; deallocate any
1055 -- associated resources. This subprogram may be called only when there is
1056 -- no other task still using Selector (i.e. still executing Check_Selector
1057 -- or Abort_Selector on this Selector).
1059 procedure Check_Selector
1060 (Selector : in out Selector_Type;
1061 R_Socket_Set : in out Socket_Set_Type;
1062 W_Socket_Set : in out Socket_Set_Type;
1063 Status : out Selector_Status;
1064 Timeout : Selector_Duration := Forever);
1065 -- Return when one Socket in R_Socket_Set has some data to be read or if
1066 -- one Socket in W_Socket_Set is ready to transmit some data. In these
1067 -- cases Status is set to Completed and sockets that are ready are set in
1068 -- R_Socket_Set or W_Socket_Set. Status is set to Expired if no socket was
1069 -- ready after a Timeout expiration. Status is set to Aborted if an abort
1070 -- signal has been received while checking socket status.
1071 -- Note that two different Socket_Set_Type objects must be passed as
1072 -- R_Socket_Set and W_Socket_Set (even if they denote the same set of
1073 -- Sockets), or some event may be lost.
1074 -- Socket_Error is raised when the select(2) system call returns an
1075 -- error condition, or when a read error occurs on the signalling socket
1076 -- used for the implementation of Abort_Selector.
1078 procedure Check_Selector
1079 (Selector : in out Selector_Type;
1080 R_Socket_Set : in out Socket_Set_Type;
1081 W_Socket_Set : in out Socket_Set_Type;
1082 E_Socket_Set : in out Socket_Set_Type;
1083 Status : out Selector_Status;
1084 Timeout : Selector_Duration := Forever);
1085 -- This refined version of Check_Selector allows watching for exception
1086 -- events (i.e. notifications of out-of-band transmission and reception).
1087 -- As above, all of R_Socket_Set, W_Socket_Set and E_Socket_Set must be
1088 -- different objects.
1090 procedure Abort_Selector (Selector : Selector_Type);
1091 -- Send an abort signal to the selector
1093 type Fd_Set is private;
1094 -- ??? This type must not be used directly, it needs to be visible because
1095 -- it is used in the visible part of GNAT.Sockets.Thin_Common. This is
1096 -- really an inversion of abstraction. The private part of GNAT.Sockets
1097 -- needs to have visibility on this type, but since Thin_Common is a child
1098 -- of Sockets, the type can't be declared there. The correct fix would
1099 -- be to move the thin sockets binding outside of GNAT.Sockets altogether,
1100 -- e.g. by renaming it to GNAT.Sockets_Thin.
1104 type Socket_Type is new Integer;
1105 No_Socket : constant Socket_Type := -1;
1107 type Selector_Type is limited record
1108 R_Sig_Socket : Socket_Type := No_Socket;
1109 W_Sig_Socket : Socket_Type := No_Socket;
1110 -- Signalling sockets used to abort a select operation
1113 pragma Volatile (Selector_Type);
1116 new System.Storage_Elements.Storage_Array (1 .. SOSC.SIZEOF_fd_set);
1117 for Fd_Set'Alignment use Interfaces.C.long'Alignment;
1118 -- Set conservative alignment so that our Fd_Sets are always adequately
1119 -- aligned for the underlying data type (which is implementation defined
1120 -- and may be an array of C long integers).
1122 type Fd_Set_Access is access all Fd_Set;
1123 pragma Convention (C, Fd_Set_Access);
1124 No_Fd_Set_Access : constant Fd_Set_Access := null;
1126 type Socket_Set_Type is record
1127 Last : Socket_Type := No_Socket;
1128 Set : aliased Fd_Set;
1131 subtype Inet_Addr_Comp_Type is Natural range 0 .. 255;
1132 -- Octet for Internet address
1134 type Inet_Addr_VN_Type is array (Natural range <>) of Inet_Addr_Comp_Type;
1136 subtype Inet_Addr_V4_Type is Inet_Addr_VN_Type (1 .. 4);
1137 subtype Inet_Addr_V6_Type is Inet_Addr_VN_Type (1 .. 16);
1139 type Inet_Addr_Type (Family : Family_Type := Family_Inet) is record
1142 Sin_V4 : Inet_Addr_V4_Type := (others => 0);
1144 when Family_Inet6 =>
1145 Sin_V6 : Inet_Addr_V6_Type := (others => 0);
1149 Any_Port : constant Port_Type := 0;
1150 No_Port : constant Port_Type := 0;
1152 Any_Inet_Addr : constant Inet_Addr_Type :=
1153 (Family_Inet, (others => 0));
1154 No_Inet_Addr : constant Inet_Addr_Type :=
1155 (Family_Inet, (others => 0));
1156 Broadcast_Inet_Addr : constant Inet_Addr_Type :=
1157 (Family_Inet, (others => 255));
1159 No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
1161 Max_Name_Length : constant := 64;
1162 -- The constant MAXHOSTNAMELEN is usually set to 64
1164 subtype Name_Index is Natural range 1 .. Max_Name_Length;
1167 (Length : Name_Index := Max_Name_Length)
1169 Name : String (1 .. Length);
1171 -- We need fixed strings to avoid access types in host entry type
1173 type Name_Array is array (Natural range <>) of Name_Type;
1174 type Inet_Addr_Array is array (Natural range <>) of Inet_Addr_Type;
1176 type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is record
1177 Official : Name_Type;
1178 Aliases : Name_Array (1 .. Aliases_Length);
1179 Addresses : Inet_Addr_Array (1 .. Addresses_Length);
1182 type Service_Entry_Type (Aliases_Length : Natural) is record
1183 Official : Name_Type;
1184 Aliases : Name_Array (1 .. Aliases_Length);
1186 Protocol : Name_Type;
1189 type Request_Flag_Type is mod 2 ** 8;
1190 No_Request_Flag : constant Request_Flag_Type := 0;
1191 Process_Out_Of_Band_Data : constant Request_Flag_Type := 1;
1192 Peek_At_Incoming_Data : constant Request_Flag_Type := 2;
1193 Wait_For_A_Full_Reception : constant Request_Flag_Type := 4;
1194 Send_End_Of_Record : constant Request_Flag_Type := 8;