1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- G N A T . S O C K E T S --
9 -- Copyright (C) 2001-2005, 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 has 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 -- -- Join a multicast group
187 -- IP_Protocol_For_IP_Level,
188 -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
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 -- -- If this socket is intended to send messages, provide the
217 -- -- receiver socket address.
219 -- Address.Addr := Inet_Addr (Group);
220 -- Address.Port := 55506;
222 -- Channel := Stream (Socket, Address);
224 -- -- Receive and print message from client Ping
227 -- Message : String := String'Input (Channel);
230 -- -- Get the address of the sender
232 -- Address := Get_Address (Channel);
233 -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
235 -- -- Send same message back to client Ping
237 -- String'Output (Channel, Message);
240 -- Close_Socket (Socket);
244 -- exception when E : others =>
245 -- Ada.Text_IO.Put_Line
246 -- (Exception_Name (E) & ": " & Exception_Message (E));
255 -- Address : Sock_Addr_Type;
256 -- Socket : Socket_Type;
257 -- Channel : Stream_Access;
262 -- -- See comments in Ping section for the first steps
264 -- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
265 -- Address.Port := 5876;
266 -- Create_Socket (Socket);
271 -- (Reuse_Address, True));
273 -- -- Force Pong to block
277 -- -- If the client's socket is not bound, Connect_Socket will
278 -- -- bind to an unused address. The client uses Connect_Socket to
279 -- -- create a logical connection between the client's socket and
280 -- -- a server's socket returned by Accept_Socket.
282 -- Connect_Socket (Socket, Address);
284 -- Channel := Stream (Socket);
286 -- -- Send message to server Pong
288 -- String'Output (Channel, "Hello world");
290 -- -- Force Ping to block
294 -- -- Receive and print message from server Pong
296 -- Ada.Text_IO.Put_Line (String'Input (Channel));
297 -- Close_Socket (Socket);
299 -- -- Part of multicast example. Code similar to Pong's one
301 -- Create_Socket (Socket, Family_Inet, Socket_Datagram);
306 -- (Reuse_Address, True));
310 -- IP_Protocol_For_IP_Level,
311 -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
315 -- IP_Protocol_For_IP_Level,
316 -- (Multicast_TTL, 1));
320 -- IP_Protocol_For_IP_Level,
321 -- (Multicast_Loop, True));
323 -- Address.Addr := Any_Inet_Addr;
324 -- Address.Port := 55506;
326 -- Bind_Socket (Socket, Address);
328 -- Address.Addr := Inet_Addr (Group);
329 -- Address.Port := 55505;
331 -- Channel := Stream (Socket, Address);
333 -- -- Send message to server Pong
335 -- String'Output (Channel, "Hello world");
337 -- -- Receive and print message from server Pong
340 -- Message : String := String'Input (Channel);
343 -- Address := Get_Address (Channel);
344 -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
347 -- Close_Socket (Socket);
351 -- exception when E : others =>
352 -- Ada.Text_IO.Put_Line
353 -- (Exception_Name (E) & ": " & Exception_Message (E));
357 -- -- Indicate whether the thread library provides process
358 -- -- blocking IO. Basically, if you are not using FSU threads
359 -- -- the default is ok.
361 -- Initialize (Process_Blocking_IO => False);
369 procedure Initialize (Process_Blocking_IO : Boolean := False);
370 -- Initialize must be called before using any other socket routines. The
371 -- Process_Blocking_IO parameter indicates whether the thread library
372 -- provides process-blocking or thread-blocking input/output operations.
373 -- In the former case (typically with FSU threads) GNAT.Sockets should be
374 -- initialized with a value of True to provide task-blocking IO through an
375 -- emulation mechanism. Only the first call to Initialize is taken into
376 -- account (further calls will be ignored). Note that with the default
377 -- value of Process_Blocking_IO, this operation is a no-op on UNIX
378 -- platforms, but applications should make sure to call it if portability
379 -- is expected: some platforms (such as Windows) require initialization
380 -- before any other socket operations.
383 -- After Finalize is called it is not possible to use any routines
384 -- exported in by this package. This procedure is idempotent.
386 type Socket_Type is private;
387 -- Sockets are used to implement a reliable bi-directional point-to-point,
388 -- stream-based connections between hosts. No_Socket provides a special
389 -- value to denote uninitialized sockets.
391 No_Socket : constant Socket_Type;
393 Socket_Error : exception;
394 -- There is only one exception in this package to deal with an error during
395 -- a socket routine. Once raised, its message contains a string describing
398 function Image (Socket : Socket_Type) return String;
399 -- Return a printable string for Socket
401 function To_C (Socket : Socket_Type) return Integer;
402 -- Return a file descriptor to be used by external subprograms. This is
403 -- useful for C functions that are not yet interfaced in this package.
405 type Family_Type is (Family_Inet, Family_Inet6);
406 -- Address family (or protocol family) identifies the communication domain
407 -- and groups protocols with similar address formats. IPv6 will soon be
410 type Mode_Type is (Socket_Stream, Socket_Datagram);
411 -- Stream sockets provide connection-oriented byte streams. Datagram
412 -- sockets support unreliable connectionless message based communication.
414 type Shutmode_Type is (Shut_Read, Shut_Write, Shut_Read_Write);
415 -- When a process closes a socket, the policy is to retain any data queued
416 -- until either a delivery or a timeout expiration (in this case, the data
417 -- are discarded). A finer control is available through shutdown. With
418 -- Shut_Read, no more data can be received from the socket. With_Write, no
419 -- more data can be transmitted. Neither transmission nor reception can be
420 -- performed with Shut_Read_Write.
422 type Port_Type is new Natural;
423 -- Classical port definition. No_Port provides a special value to
424 -- denote uninitialized port. Any_Port provides a special value
425 -- enabling all ports.
427 Any_Port : constant Port_Type;
428 No_Port : constant Port_Type;
430 type Inet_Addr_Type (Family : Family_Type := Family_Inet) is private;
431 -- An Internet address depends on an address family (IPv4 contains 4
432 -- octets and Ipv6 contains 16 octets). Any_Inet_Addr is a special value
433 -- treated like a wildcard enabling all addresses. No_Inet_Addr provides a
434 -- special value to denote uninitialized inet addresses.
436 Any_Inet_Addr : constant Inet_Addr_Type;
437 No_Inet_Addr : constant Inet_Addr_Type;
438 Broadcast_Inet_Addr : constant Inet_Addr_Type;
440 type Sock_Addr_Type (Family : Family_Type := Family_Inet) is record
441 Addr : Inet_Addr_Type (Family);
444 -- Socket addresses fully define a socket connection with protocol family,
445 -- an Internet address and a port. No_Sock_Addr provides a special value
446 -- for uninitialized socket addresses.
448 No_Sock_Addr : constant Sock_Addr_Type;
450 function Image (Value : Inet_Addr_Type) return String;
451 -- Return an image of an Internet address. IPv4 notation consists in 4
452 -- octets in decimal format separated by dots. IPv6 notation consists in
453 -- 16 octets in hexadecimal format separated by colons (and possibly
456 function Image (Value : Sock_Addr_Type) return String;
457 -- Return inet address image and port image separated by a colon
459 function Inet_Addr (Image : String) return Inet_Addr_Type;
460 -- Convert address image from numbers-and-dots notation into an
463 -- Host entries provide complete information on a given host: the official
464 -- name, an array of alternative names or aliases and array of network
468 (Aliases_Length, Addresses_Length : Natural) is private;
470 function Official_Name (E : Host_Entry_Type) return String;
471 -- Return official name in host entry
473 function Aliases_Length (E : Host_Entry_Type) return Natural;
474 -- Return number of aliases in host entry
476 function Addresses_Length (E : Host_Entry_Type) return Natural;
477 -- Return number of addresses in host entry
480 (E : Host_Entry_Type;
481 N : Positive := 1) return String;
482 -- Return N'th aliases in host entry. The first index is 1
485 (E : Host_Entry_Type;
486 N : Positive := 1) return Inet_Addr_Type;
487 -- Return N'th addresses in host entry. The first index is 1
489 Host_Error : exception;
490 -- Exception raised by the two following procedures. Once raised, its
491 -- message contains a string describing the error code. This exception is
492 -- raised when an host entry cannot be retrieved.
494 function Get_Host_By_Address
495 (Address : Inet_Addr_Type;
496 Family : Family_Type := Family_Inet) return Host_Entry_Type;
497 -- Return host entry structure for the given Inet address. Note that no
498 -- result will be returned if there is no mapping of this IP address to a
499 -- host name in the system tables (host database, DNS or otherwise).
501 function Get_Host_By_Name
502 (Name : String) return Host_Entry_Type;
503 -- Return host entry structure for the given host name. Here name is
504 -- either a host name, or an IP address. If Name is an IP address, this is
505 -- equivalent to Get_Host_By_Address (Inet_Addr (Name)).
507 function Host_Name return String;
508 -- Return the name of the current host
510 type Service_Entry_Type (Aliases_Length : Natural) is private;
511 -- Service entries provide complete information on a given service: the
512 -- official name, an array of alternative names or aliases and the port
515 function Official_Name (S : Service_Entry_Type) return String;
516 -- Return official name in service entry
518 function Port_Number (S : Service_Entry_Type) return Port_Type;
519 -- Return port number in service entry
521 function Protocol_Name (S : Service_Entry_Type) return String;
522 -- Return Protocol in service entry (usually UDP or TCP)
524 function Aliases_Length (S : Service_Entry_Type) return Natural;
525 -- Return number of aliases in service entry
528 (S : Service_Entry_Type;
529 N : Positive := 1) return String;
530 -- Return N'th aliases in service entry (the first index is 1)
532 function Get_Service_By_Name
534 Protocol : String) return Service_Entry_Type;
535 -- Return service entry structure for the given service name
537 function Get_Service_By_Port
539 Protocol : String) return Service_Entry_Type;
540 -- Return service entry structure for the given service port number
542 Service_Error : exception;
543 -- Comment required ???
545 -- Errors are described by an enumeration type. There is only one
546 -- exception Socket_Error in this package to deal with an error during a
547 -- socket routine. Once raised, its message contains the error code
548 -- between brackets and a string describing the error code.
550 -- The name of the enumeration constant documents the error condition
555 Address_Already_In_Use,
556 Cannot_Assign_Requested_Address,
557 Address_Family_Not_Supported_By_Protocol,
558 Operation_Already_In_Progress,
560 Software_Caused_Connection_Abort,
562 Connection_Reset_By_Peer,
563 Destination_Address_Required,
567 Operation_Now_In_Progress,
568 Interrupted_System_Call,
571 Transport_Endpoint_Already_Connected,
572 Too_Many_Symbolic_Links,
577 Network_Dropped_Connection_Because_Of_Reset,
578 Network_Is_Unreachable,
579 No_Buffer_Space_Available,
580 Protocol_Not_Available,
581 Transport_Endpoint_Not_Connected,
582 Socket_Operation_On_Non_Socket,
583 Operation_Not_Supported,
584 Protocol_Family_Not_Supported,
585 Protocol_Not_Supported,
586 Protocol_Wrong_Type_For_Socket,
587 Cannot_Send_After_Transport_Endpoint_Shutdown,
588 Socket_Type_Not_Supported,
589 Connection_Timed_Out,
591 Resource_Temporarily_Unavailable,
593 Host_Name_Lookup_Failure,
594 Non_Recoverable_Error,
595 Unknown_Server_Error,
596 Cannot_Resolve_Error);
598 -- Timeval_Duration is a subtype of Standard.Duration because the full
599 -- range of Standard.Duration cannot be represented in the equivalent C
600 -- structure. Moreover, negative values are not allowed to avoid system
601 -- incompatibilities.
603 Immediate : constant := 0.0;
604 Forever : constant := Duration (Integer'Last) * 1.0;
606 subtype Timeval_Duration is Duration range Immediate .. Forever;
608 -- Get_Socket_Options and Set_Socket_Options manipulate options associated
609 -- with a socket. Options may exist at multiple protocol levels in the
610 -- communication stack. Socket_Level is the uppermost socket level.
614 IP_Protocol_For_IP_Level,
615 IP_Protocol_For_UDP_Level,
616 IP_Protocol_For_TCP_Level);
618 -- There are several options available to manipulate sockets. Each option
619 -- has a name and several values available. Most of the time, the value is
620 -- a boolean to enable or disable this option.
622 type Option_Name is (
623 Keep_Alive, -- Enable sending of keep-alive messages
624 Reuse_Address, -- Allow bind to reuse local address
625 Broadcast, -- Enable datagram sockets to recv/send broadcasts
626 Send_Buffer, -- Set/get the maximum socket send buffer in bytes
627 Receive_Buffer, -- Set/get the maximum socket recv buffer in bytes
628 Linger, -- Shutdown wait for msg to be sent or timeout occur
629 Error, -- Get and clear the pending socket error
630 No_Delay, -- Do not delay send to coalesce packets (TCP_NODELAY)
631 Add_Membership, -- Join a multicast group
632 Drop_Membership, -- Leave a multicast group
633 Multicast_If, -- Set default outgoing interface for multicast packets
634 Multicast_TTL, -- Indicate the time-to-live of sent multicast packets
635 Multicast_Loop, -- Sent multicast packets are looped to local socket
636 Send_Timeout, -- Set timeout value for output
637 Receive_Timeout); -- Set timeout value for input
639 type Option_Type (Name : Option_Name := Keep_Alive) is record
663 when Add_Membership |
665 Multicast_Address : Inet_Addr_Type;
666 Local_Interface : Inet_Addr_Type;
669 Outgoing_If : Inet_Addr_Type;
671 when Multicast_TTL =>
672 Time_To_Live : Natural;
676 Timeout : Timeval_Duration;
681 -- There are several controls available to manipulate sockets. Each option
682 -- has a name and several values available. These controls differ from the
683 -- socket options in that they are not specific to sockets but are
684 -- available for any device.
686 type Request_Name is (
687 Non_Blocking_IO, -- Cause a caller not to wait on blocking operations.
688 N_Bytes_To_Read); -- Return the number of bytes available to read
690 type Request_Type (Name : Request_Name := Non_Blocking_IO) is record
692 when Non_Blocking_IO =>
695 when N_Bytes_To_Read =>
701 -- A request flag allows to specify the type of message transmissions or
702 -- receptions. A request flag can be combination of zero or more
703 -- predefined request flags.
705 type Request_Flag_Type is private;
707 No_Request_Flag : constant Request_Flag_Type;
708 -- This flag corresponds to the normal execution of an operation
710 Process_Out_Of_Band_Data : constant Request_Flag_Type;
711 -- This flag requests that the receive or send function operates on
712 -- out-of-band data when the socket supports this notion (e.g.
715 Peek_At_Incoming_Data : constant Request_Flag_Type;
716 -- This flag causes the receive operation to return data from the
717 -- beginning of the receive queue without removing that data from the
718 -- queue. A subsequent receive call will return the same data.
720 Wait_For_A_Full_Reception : constant Request_Flag_Type;
721 -- This flag requests that the operation block until the full request is
722 -- satisfied. However, the call may still return less data than requested
723 -- if a signal is caught, an error or disconnect occurs, or the next data
724 -- to be received is of a different type than that returned. Note that
725 -- this flag depends on support in the underlying sockets implementation,
726 -- and is not supported under Windows.
728 Send_End_Of_Record : constant Request_Flag_Type;
729 -- This flag indicates that the entire message has been sent and so this
730 -- terminates the record.
732 function "+" (L, R : Request_Flag_Type) return Request_Flag_Type;
733 -- Combine flag L with flag R
735 type Stream_Element_Reference is access all Ada.Streams.Stream_Element;
737 type Vector_Element is record
738 Base : Stream_Element_Reference;
739 Length : Ada.Streams.Stream_Element_Count;
742 type Vector_Type is array (Integer range <>) of Vector_Element;
744 procedure Create_Socket
745 (Socket : out Socket_Type;
746 Family : Family_Type := Family_Inet;
747 Mode : Mode_Type := Socket_Stream);
748 -- Create an endpoint for communication. Raises Socket_Error on error
750 procedure Accept_Socket
751 (Server : Socket_Type;
752 Socket : out Socket_Type;
753 Address : out Sock_Addr_Type);
754 -- Extracts the first connection request on the queue of pending
755 -- connections, creates a new connected socket with mostly the same
756 -- properties as Server, and allocates a new socket. The returned Address
757 -- is filled in with the address of the connection. Raises Socket_Error on
760 procedure Bind_Socket
761 (Socket : Socket_Type;
762 Address : Sock_Addr_Type);
763 -- Once a socket is created, assign a local address to it. Raise
764 -- Socket_Error on error.
766 procedure Close_Socket (Socket : Socket_Type);
767 -- Close a socket and more specifically a non-connected socket
769 procedure Connect_Socket
770 (Socket : Socket_Type;
771 Server : in out Sock_Addr_Type);
772 -- Make a connection to another socket which has the address of
773 -- Server. Raises Socket_Error on error.
775 procedure Control_Socket
776 (Socket : Socket_Type;
777 Request : in out Request_Type);
778 -- Obtain or set parameter values that control the socket. This control
779 -- differs from the socket options in that they are not specific to
780 -- sockets but are available for any device.
782 function Get_Peer_Name (Socket : Socket_Type) return Sock_Addr_Type;
783 -- Return the peer or remote socket address of a socket. Raise
784 -- Socket_Error on error.
786 function Get_Socket_Name (Socket : Socket_Type) return Sock_Addr_Type;
787 -- Return the local or current socket address of a socket. Return
788 -- No_Sock_Addr on error (for instance, socket closed or not locally
791 function Get_Socket_Option
792 (Socket : Socket_Type;
793 Level : Level_Type := Socket_Level;
794 Name : Option_Name) return Option_Type;
795 -- Get the options associated with a socket. Raises Socket_Error
798 procedure Listen_Socket
799 (Socket : Socket_Type;
800 Length : Positive := 15);
801 -- To accept connections, a socket is first created with Create_Socket,
802 -- a willingness to accept incoming connections and a queue Length for
803 -- incoming connections are specified. Raise Socket_Error on error.
805 procedure Receive_Socket
806 (Socket : Socket_Type;
807 Item : out Ada.Streams.Stream_Element_Array;
808 Last : out Ada.Streams.Stream_Element_Offset;
809 Flags : Request_Flag_Type := No_Request_Flag);
810 -- Receive message from Socket. Last is the index value such that Item
811 -- (Last) is the last character assigned. Note that Last is set to
812 -- Item'First - 1 when the socket has been closed by peer. This is not an
813 -- error and no exception is raised. Flags allows to control the
814 -- reception. Raise Socket_Error on error.
816 procedure Receive_Socket
817 (Socket : Socket_Type;
818 Item : out Ada.Streams.Stream_Element_Array;
819 Last : out Ada.Streams.Stream_Element_Offset;
820 From : out Sock_Addr_Type;
821 Flags : Request_Flag_Type := No_Request_Flag);
822 -- Receive message from Socket. If Socket is not connection-oriented, the
823 -- source address From of the message is filled in. Last is the index
824 -- value such that Item (Last) is the last character assigned. Flags
825 -- allows to control the reception. Raises Socket_Error on error.
827 procedure Receive_Vector
828 (Socket : Socket_Type;
829 Vector : Vector_Type;
830 Count : out Ada.Streams.Stream_Element_Count);
831 -- Receive data from a socket and scatter it into the set of vector
832 -- elements Vector. Count is set to the count of received stream elements.
834 function Resolve_Exception
835 (Occurrence : Ada.Exceptions.Exception_Occurrence) return Error_Type;
836 -- When Socket_Error or Host_Error are raised, the exception message
837 -- contains the error code between brackets and a string describing the
838 -- error code. Resolve_Error extracts the error code from an exception
839 -- message and translate it into an enumeration value.
841 procedure Send_Socket
842 (Socket : Socket_Type;
843 Item : Ada.Streams.Stream_Element_Array;
844 Last : out Ada.Streams.Stream_Element_Offset;
845 Flags : Request_Flag_Type := No_Request_Flag);
846 -- Transmit a message to another socket. Note that Last is set to
847 -- Item'First-1 when socket has been closed by peer. This is not
848 -- considered an error and no exception is raised. Flags allows to control
849 -- the transmission. Raises Socket_Error on any other error condition.
851 procedure Send_Socket
852 (Socket : Socket_Type;
853 Item : Ada.Streams.Stream_Element_Array;
854 Last : out Ada.Streams.Stream_Element_Offset;
856 Flags : Request_Flag_Type := No_Request_Flag);
857 -- Transmit a message to another socket. The address is given by To. Flags
858 -- allows to control the transmission. Raises Socket_Error on error.
860 procedure Send_Vector
861 (Socket : Socket_Type;
862 Vector : Vector_Type;
863 Count : out Ada.Streams.Stream_Element_Count);
864 -- Transmit data gathered from the set of vector elements Vector to a
865 -- socket. Count is set to the count of transmitted stream elements.
867 procedure Set_Socket_Option
868 (Socket : Socket_Type;
869 Level : Level_Type := Socket_Level;
870 Option : Option_Type);
871 -- Manipulate socket options. Raises Socket_Error on error
873 procedure Shutdown_Socket
874 (Socket : Socket_Type;
875 How : Shutmode_Type := Shut_Read_Write);
876 -- Shutdown a connected socket. If How is Shut_Read, further receives will
877 -- be disallowed. If How is Shut_Write, further sends will be disallowed.
878 -- If how is Shut_Read_Write, further sends and receives will be
881 type Stream_Access is access all Ada.Streams.Root_Stream_Type'Class;
882 -- Same interface as Ada.Streams.Stream_IO
885 (Socket : Socket_Type) return Stream_Access;
886 -- Create a stream associated with a stream-based socket that is
887 -- already connected.
890 (Socket : Socket_Type;
891 Send_To : Sock_Addr_Type) return Stream_Access;
892 -- Create a stream associated with a datagram-based socket that is already
893 -- bound. Send_To is the socket address to which messages are being sent.
896 (Stream : Stream_Access) return Sock_Addr_Type;
897 -- Return the socket address from which the last message was received
899 procedure Free is new Ada.Unchecked_Deallocation
900 (Ada.Streams.Root_Stream_Type'Class, Stream_Access);
901 -- Destroy a stream created by one of the Stream functions above,
902 -- releasing the corresponding resources. The user is responsible for
903 -- calling this subprogram when the stream is not needed anymore.
905 type Socket_Set_Type is limited private;
906 -- This type allows to manipulate sets of sockets. It allows to wait for
907 -- events on multiple endpoints at one time. This is an access type on a
908 -- system dependent structure. To avoid memory leaks it is highly
909 -- recommended to clean the access value with procedure Empty.
911 procedure Clear (Item : in out Socket_Set_Type; Socket : Socket_Type);
912 -- Remove Socket from Item
914 procedure Copy (Source : Socket_Set_Type; Target : in out Socket_Set_Type);
915 -- Copy Source into Target as Socket_Set_Type is limited private
917 procedure Empty (Item : in out Socket_Set_Type);
918 -- Remove all Sockets from Item and deallocate internal data
920 procedure Get (Item : in out Socket_Set_Type; Socket : out Socket_Type);
921 -- Extract a Socket from socket set Item. Socket is set to
922 -- No_Socket when the set is empty.
925 (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
966 type Selector_Status is (Completed, Expired, Aborted);
968 procedure Check_Selector
969 (Selector : in out Selector_Type;
970 R_Socket_Set : in out Socket_Set_Type;
971 W_Socket_Set : in out Socket_Set_Type;
972 Status : out Selector_Status;
973 Timeout : Selector_Duration := Forever);
974 -- Return when one Socket in R_Socket_Set has some data to be read or if
975 -- one Socket in W_Socket_Set is ready to transmit some data. In these
976 -- cases Status is set to Completed and sockets that are ready are set in
977 -- R_Socket_Set or W_Socket_Set. Status is set to Expired if no socket was
978 -- ready after a Timeout expiration. Status is set to Aborted if an abort
979 -- signal has been received while checking socket status. As this
980 -- procedure returns when Timeout occurs, it is a design choice to keep
981 -- this procedure process blocking. Note that a Timeout of 0.0 returns
982 -- immediately. Also note that two different Socket_Set_Type objects must
983 -- be passed as R_Socket_Set and W_Socket_Set (even if they denote the
984 -- same set of Sockets), or some event may be lost.
985 -- Socket_Error is raised when the select(2) system call returns an
986 -- error condition, or when a read error occurs on the signalling socket
987 -- used for the implementation of Abort_Selector.
989 procedure Check_Selector
990 (Selector : in out Selector_Type;
991 R_Socket_Set : in out Socket_Set_Type;
992 W_Socket_Set : in out Socket_Set_Type;
993 E_Socket_Set : in out Socket_Set_Type;
994 Status : out Selector_Status;
995 Timeout : Selector_Duration := Forever);
996 -- This refined version of Check_Selector allows to watch for exception
997 -- events (that is notifications of out-of-band transmission and
998 -- reception). As above, all of R_Socket_Set, W_Socket_Set and
999 -- E_Socket_Set must be different objects.
1001 procedure Abort_Selector (Selector : Selector_Type);
1002 -- Send an abort signal to the selector
1006 type Socket_Type is new Integer;
1007 No_Socket : constant Socket_Type := -1;
1009 type Selector_Type is limited record
1010 R_Sig_Socket : Socket_Type;
1011 W_Sig_Socket : Socket_Type;
1014 pragma Volatile (Selector_Type);
1016 -- The two signalling sockets are used to abort a select operation
1018 subtype Socket_Set_Access is System.Address;
1019 No_Socket_Set : constant Socket_Set_Access := System.Null_Address;
1021 type Socket_Set_Type is record
1022 Last : Socket_Type := No_Socket;
1023 Set : Socket_Set_Access := No_Socket_Set;
1026 subtype Inet_Addr_Comp_Type is Natural range 0 .. 255;
1027 -- Octet for Internet address
1029 type Inet_Addr_VN_Type is array (Natural range <>) of Inet_Addr_Comp_Type;
1031 subtype Inet_Addr_V4_Type is Inet_Addr_VN_Type (1 .. 4);
1032 subtype Inet_Addr_V6_Type is Inet_Addr_VN_Type (1 .. 16);
1034 type Inet_Addr_Type (Family : Family_Type := Family_Inet) is record
1037 Sin_V4 : Inet_Addr_V4_Type := (others => 0);
1039 when Family_Inet6 =>
1040 Sin_V6 : Inet_Addr_V6_Type := (others => 0);
1044 Any_Port : constant Port_Type := 0;
1045 No_Port : constant Port_Type := 0;
1047 Any_Inet_Addr : constant Inet_Addr_Type :=
1048 (Family_Inet, (others => 0));
1049 No_Inet_Addr : constant Inet_Addr_Type :=
1050 (Family_Inet, (others => 0));
1051 Broadcast_Inet_Addr : constant Inet_Addr_Type :=
1052 (Family_Inet, (others => 255));
1054 No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
1056 Max_Name_Length : constant := 64;
1057 -- The constant MAXHOSTNAMELEN is usually set to 64
1059 subtype Name_Index is Natural range 1 .. Max_Name_Length;
1062 (Length : Name_Index := Max_Name_Length)
1064 Name : String (1 .. Length);
1066 -- We need fixed strings to avoid access types in host entry type
1068 type Name_Array is array (Natural range <>) of Name_Type;
1069 type Inet_Addr_Array is array (Natural range <>) of Inet_Addr_Type;
1071 type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is record
1072 Official : Name_Type;
1073 Aliases : Name_Array (1 .. Aliases_Length);
1074 Addresses : Inet_Addr_Array (1 .. Addresses_Length);
1077 type Service_Entry_Type (Aliases_Length : Natural) is record
1078 Official : Name_Type;
1079 Aliases : Name_Array (1 .. Aliases_Length);
1081 Protocol : Name_Type;
1084 type Request_Flag_Type is mod 2 ** 8;
1085 No_Request_Flag : constant Request_Flag_Type := 0;
1086 Process_Out_Of_Band_Data : constant Request_Flag_Type := 1;
1087 Peek_At_Incoming_Data : constant Request_Flag_Type := 2;
1088 Wait_For_A_Full_Reception : constant Request_Flag_Type := 4;
1089 Send_End_Of_Record : constant Request_Flag_Type := 8;