1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- G N A T . S O C K E T S --
9 -- Copyright (C) 2001-2018, 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 3, 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. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 -- This package provides an interface to the sockets communication facility
33 -- provided on many operating systems. This is implemented on the following
36 -- All native ports, with restrictions as follows
38 -- Multicast is available only on systems which provide support for this
39 -- feature, so it is not available if Multicast is not supported, or not
42 -- VxWorks cross ports fully implement this package
44 -- This package is not yet implemented on LynxOS or other cross ports
48 with Ada
.Unchecked_Deallocation
;
52 with System
.OS_Constants
;
53 with System
.Storage_Elements
;
55 package GNAT
.Sockets
is
57 -- Sockets are designed to provide a consistent communication facility
58 -- between applications. This package provides an Ada binding to the
59 -- de-facto standard BSD sockets API. The documentation below covers
60 -- only the specific binding provided by this package. It assumes that
61 -- the reader is already familiar with general network programming and
62 -- sockets usage. A useful reference on this matter is W. Richard Stevens'
63 -- "UNIX Network Programming: The Sockets Networking API"
64 -- (ISBN: 0131411551).
66 -- GNAT.Sockets has been designed with several ideas in mind
68 -- This is a system independent interface. Therefore, we try as much as
69 -- possible to mask system incompatibilities. Some functionalities are not
70 -- available because there are not fully supported on some systems.
72 -- This is a thick binding. For instance, a major effort has been done to
73 -- avoid using memory addresses or untyped ints. We preferred to define
74 -- streams and enumeration types. Errors are not returned as returned
75 -- values but as exceptions.
77 -- This package provides a POSIX-compliant interface (between two
78 -- different implementations of the same routine, we adopt the one closest
79 -- to the POSIX specification). For instance, using select(), the
80 -- notification of an asynchronous connect failure is delivered in the
81 -- write socket set (POSIX) instead of the exception socket set (NT).
83 -- The example below demonstrates various features of GNAT.Sockets:
85 -- with GNAT.Sockets; use GNAT.Sockets;
88 -- with Ada.Exceptions; use Ada.Exceptions;
90 -- procedure PingPong is
92 -- Group : constant String := "239.255.128.128";
93 -- -- Multicast group: administratively scoped IP address
101 -- Address : Sock_Addr_Type;
102 -- Server : Socket_Type;
103 -- Socket : Socket_Type;
104 -- 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.
145 -- Accept_Socket (Server, Socket, Address);
147 -- -- Return a stream associated to the connected socket
149 -- Channel := Stream (Socket);
151 -- -- Force Pong to block
155 -- -- Receive and print message from client Ping
158 -- Message : String := String'Input (Channel);
161 -- Ada.Text_IO.Put_Line (Message);
163 -- -- Send same message back to client Ping
165 -- String'Output (Channel, Message);
168 -- Close_Socket (Server);
169 -- Close_Socket (Socket);
171 -- -- Part of the multicast example
173 -- -- Create a datagram socket to send connectionless, unreliable
174 -- -- messages of a fixed maximum length.
176 -- Create_Socket (Socket, Family_Inet, Socket_Datagram);
178 -- -- Allow reuse of local addresses
183 -- (Reuse_Address, True));
185 -- -- Controls the live time of the datagram to avoid it being
186 -- -- looped forever due to routing errors. Routers decrement
187 -- -- the TTL of every datagram as it traverses from one network
188 -- -- to another and when its value reaches 0 the packet is
189 -- -- dropped. Default is 1.
193 -- IP_Protocol_For_IP_Level,
194 -- (Multicast_TTL, 1));
196 -- -- Want the data you send to be looped back to your host
200 -- IP_Protocol_For_IP_Level,
201 -- (Multicast_Loop, True));
203 -- -- If this socket is intended to receive messages, bind it
204 -- -- to a given socket address.
206 -- Address.Addr := Any_Inet_Addr;
207 -- Address.Port := 55505;
209 -- Bind_Socket (Socket, Address);
211 -- -- Join a multicast group
213 -- -- Portability note: On Windows, this option may be set only
214 -- -- on a bound socket.
218 -- IP_Protocol_For_IP_Level,
219 -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
221 -- -- If this socket is intended to send messages, provide the
222 -- -- receiver socket address.
224 -- Address.Addr := Inet_Addr (Group);
225 -- Address.Port := 55506;
227 -- Channel := Stream (Socket, Address);
229 -- -- Receive and print message from client Ping
232 -- Message : String := String'Input (Channel);
235 -- -- Get the address of the sender
237 -- Address := Get_Address (Channel);
238 -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
240 -- -- Send same message back to client Ping
242 -- String'Output (Channel, Message);
245 -- Close_Socket (Socket);
249 -- exception when E : others =>
250 -- Ada.Text_IO.Put_Line
251 -- (Exception_Name (E) & ": " & Exception_Message (E));
260 -- Address : Sock_Addr_Type;
261 -- Socket : Socket_Type;
262 -- Channel : Stream_Access;
267 -- -- See comments in Ping section for the first steps
269 -- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
270 -- Address.Port := 5876;
271 -- Create_Socket (Socket);
276 -- (Reuse_Address, True));
278 -- -- Force Ping to block
282 -- -- If the client's socket is not bound, Connect_Socket will
283 -- -- bind to an unused address. The client uses Connect_Socket to
284 -- -- create a logical connection between the client's socket and
285 -- -- a server's socket returned by Accept_Socket.
287 -- Connect_Socket (Socket, Address);
289 -- Channel := Stream (Socket);
291 -- -- Send message to server Pong
293 -- String'Output (Channel, "Hello world");
295 -- -- Force Ping to block
299 -- -- Receive and print message from server Pong
301 -- Ada.Text_IO.Put_Line (String'Input (Channel));
302 -- Close_Socket (Socket);
304 -- -- Part of multicast example. Code similar to Pong's one
306 -- Create_Socket (Socket, Family_Inet, Socket_Datagram);
311 -- (Reuse_Address, True));
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);
330 -- IP_Protocol_For_IP_Level,
331 -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
333 -- Address.Addr := Inet_Addr (Group);
334 -- Address.Port := 55505;
336 -- Channel := Stream (Socket, Address);
338 -- -- Send message to server Pong
340 -- String'Output (Channel, "Hello world");
342 -- -- Receive and print message from server Pong
345 -- Message : String := String'Input (Channel);
348 -- Address := Get_Address (Channel);
349 -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
352 -- Close_Socket (Socket);
356 -- exception when E : others =>
357 -- Ada.Text_IO.Put_Line
358 -- (Exception_Name (E) & ": " & Exception_Message (E));
370 package SOSC
renames System
.OS_Constants
;
371 -- Renaming used to provide short-hand notations throughout the sockets
372 -- binding. Note that System.OS_Constants is an internal unit, and the
373 -- entities declared therein are not meant for direct access by users,
374 -- including through this renaming.
376 use type Interfaces
.C
.int
;
377 -- Need visibility on "-" operator so that we can write -1
379 procedure Initialize
;
381 (Entity
=> Initialize
,
382 Message
=> "explicit initialization is no longer required");
383 -- Initialize must be called before using any other socket routines.
384 -- Note that this operation is a no-op on UNIX platforms, but applications
385 -- should make sure to call it if portability is expected: some platforms
386 -- (such as Windows) require initialization before any socket operation.
387 -- This is now a no-op (initialization and finalization are done
390 procedure Initialize
(Process_Blocking_IO
: Boolean);
392 (Entity
=> Initialize
,
393 Message
=> "passing a parameter to Initialize is no longer supported");
394 -- Previous versions of GNAT.Sockets used to require the user to indicate
395 -- whether socket I/O was process- or thread-blocking on the platform.
396 -- This property is now determined automatically when the run-time library
397 -- is built. The old version of Initialize, taking a parameter, is kept
398 -- for compatibility reasons, but this interface is obsolete (and if the
399 -- value given is wrong, an exception will be raised at run time).
400 -- This is now a no-op (initialization and finalization are done
406 Message
=> "explicit finalization is no longer required");
407 -- After Finalize is called it is not possible to use any routines
408 -- exported in by this package. This procedure is idempotent.
409 -- This is now a no-op (initialization and finalization are done
412 type Socket_Type
is private;
413 -- Sockets are used to implement a reliable bi-directional point-to-point,
414 -- stream-based connections between hosts. No_Socket provides a special
415 -- value to denote uninitialized sockets.
417 No_Socket
: constant Socket_Type
;
419 type Selector_Type
is limited private;
420 type Selector_Access
is access all Selector_Type
;
421 -- Selector objects are used to wait for i/o events to occur on sockets
423 Null_Selector
: constant Selector_Type
;
424 -- The Null_Selector can be used in place of a normal selector without
425 -- having to call Create_Selector if the use of Abort_Selector is not
428 -- Timeval_Duration is a subtype of Standard.Duration because the full
429 -- range of Standard.Duration cannot be represented in the equivalent C
430 -- structure (struct timeval). Moreover, negative values are not allowed
431 -- to avoid system incompatibilities.
433 Immediate
: constant Duration := 0.0;
435 Forever
: constant Duration :=
436 Duration'Min (Duration'Last, 1.0 * SOSC
.MAX_tv_sec
);
437 -- Largest possible Duration that is also a valid value for struct timeval
439 subtype Timeval_Duration
is Duration range Immediate
.. Forever
;
441 subtype Selector_Duration
is Timeval_Duration
;
442 -- Timeout value for selector operations
444 type Selector_Status
is (Completed
, Expired
, Aborted
);
445 -- Completion status of a selector operation, indicated as follows:
446 -- Complete: one of the expected events occurred
447 -- Expired: no event occurred before the expiration of the timeout
448 -- Aborted: an external action cancelled the wait operation before
449 -- any event occurred.
451 Socket_Error
: exception;
452 -- There is only one exception in this package to deal with an error during
453 -- a socket routine. Once raised, its message contains a string describing
456 function Image
(Socket
: Socket_Type
) return String;
457 -- Return a printable string for Socket
459 function To_Ada
(Fd
: Integer) return Socket_Type
with Inline
;
460 -- Convert a file descriptor to Socket_Type. This is useful when a socket
461 -- file descriptor is obtained from an external library call.
463 function To_C
(Socket
: Socket_Type
) return Integer with Inline
;
464 -- Return a file descriptor to be used by external subprograms. This is
465 -- useful for C functions that are not yet interfaced in this package.
467 type Family_Type
is (Family_Inet
, Family_Inet6
);
468 -- Address family (or protocol family) identifies the communication domain
469 -- and groups protocols with similar address formats.
471 type Mode_Type
is (Socket_Stream
, Socket_Datagram
);
472 -- Stream sockets provide connection-oriented byte streams. Datagram
473 -- sockets support unreliable connectionless message based communication.
475 type Shutmode_Type
is (Shut_Read
, Shut_Write
, Shut_Read_Write
);
476 -- When a process closes a socket, the policy is to retain any data queued
477 -- until either a delivery or a timeout expiration (in this case, the data
478 -- are discarded). A finer control is available through shutdown. With
479 -- Shut_Read, no more data can be received from the socket. With_Write, no
480 -- more data can be transmitted. Neither transmission nor reception can be
481 -- performed with Shut_Read_Write.
483 type Port_Type
is range 0 .. 16#ffff#
;
484 -- TCP/UDP port number
486 Any_Port
: constant Port_Type
;
489 No_Port
: constant Port_Type
;
490 -- Uninitialized port number
492 type Inet_Addr_Comp_Type
is mod 2 ** 8;
493 -- Octet for Internet address
495 Inet_Addr_Bytes_Length
: constant array (Family_Type
) of Positive :=
496 (Family_Inet
=> 4, Family_Inet6
=> 16);
498 type Inet_Addr_Bytes
is array (Natural range <>) of Inet_Addr_Comp_Type
;
500 subtype Inet_Addr_V4_Type
is
501 Inet_Addr_Bytes
(1 .. Inet_Addr_Bytes_Length
(Family_Inet
));
502 subtype Inet_Addr_V6_Type
is
503 Inet_Addr_Bytes
(1 .. Inet_Addr_Bytes_Length
(Family_Inet6
));
505 subtype Inet_Addr_VN_Type
is Inet_Addr_Bytes
;
506 -- For backwards compatibility
508 type Inet_Addr_Type
(Family
: Family_Type
:= Family_Inet
) is record
511 Sin_V4
: Inet_Addr_V4_Type
:= (others => 0);
514 Sin_V6
: Inet_Addr_V6_Type
:= (others => 0);
518 -- An Internet address depends on an address family (IPv4 contains 4 octets
519 -- and IPv6 contains 16 octets). Any_Inet_Addr is a special value treated
520 -- like a wildcard enabling all addresses. No_Inet_Addr provides a special
521 -- value to denote uninitialized inet addresses.
523 Any_Inet_Addr
: constant Inet_Addr_Type
;
524 No_Inet_Addr
: constant Inet_Addr_Type
;
525 Broadcast_Inet_Addr
: constant Inet_Addr_Type
;
526 Loopback_Inet_Addr
: constant Inet_Addr_Type
;
528 -- Useful constants for IPv4 multicast addresses
530 Unspecified_Group_Inet_Addr
: constant Inet_Addr_Type
;
531 All_Hosts_Group_Inet_Addr
: constant Inet_Addr_Type
;
532 All_Routers_Group_Inet_Addr
: constant Inet_Addr_Type
;
534 -- Functions to handle masks and prefixes
537 (Family
: Family_Type
;
539 Host
: Boolean := False) return Inet_Addr_Type
;
540 -- Return an address mask of the given family with the given prefix length.
541 -- If Host is False, this is a network mask (i.e. network bits are 1,
542 -- and host bits are 0); if Host is True, this is a host mask (i.e.
543 -- network bits are 0, and host bits are 1).
545 function "and" (Addr
, Mask
: Inet_Addr_Type
) return Inet_Addr_Type
;
546 function "or" (Net
, Host
: Inet_Addr_Type
) return Inet_Addr_Type
;
547 function "not" (Mask
: Inet_Addr_Type
) return Inet_Addr_Type
;
548 -- Bit-wise operations on inet addresses (both operands must have the
549 -- same address family).
551 type Sock_Addr_Type
(Family
: Family_Type
:= Family_Inet
) is record
552 Addr
: Inet_Addr_Type
(Family
);
555 pragma No_Component_Reordering
(Sock_Addr_Type
);
556 -- Socket addresses fully define a socket connection with protocol family,
557 -- an Internet address and a port. No_Sock_Addr provides a special value
558 -- for uninitialized socket addresses.
560 No_Sock_Addr
: constant Sock_Addr_Type
;
562 function Image
(Value
: Inet_Addr_Type
) return String;
563 -- Return an image of an Internet address. IPv4 notation consists in 4
564 -- octets in decimal format separated by dots. IPv6 notation consists in
565 -- 16 octets in hexadecimal format separated by colons (and possibly
568 function Image
(Value
: Sock_Addr_Type
) return String;
569 -- Return inet address image and port image separated by a colon
571 function Inet_Addr
(Image
: String) return Inet_Addr_Type
;
572 -- Convert address image from numbers-and-dots notation into an
575 -- Host entries provide complete information on a given host: the official
576 -- name, an array of alternative names or aliases and array of network
580 (Aliases_Length
, Addresses_Length
: Natural) is private;
582 function Official_Name
(E
: Host_Entry_Type
) return String;
583 -- Return official name in host entry
585 function Aliases_Length
(E
: Host_Entry_Type
) return Natural;
586 -- Return number of aliases in host entry
588 function Addresses_Length
(E
: Host_Entry_Type
) return Natural;
589 -- Return number of addresses in host entry
592 (E
: Host_Entry_Type
;
593 N
: Positive := 1) return String;
594 -- Return N'th aliases in host entry. The first index is 1
597 (E
: Host_Entry_Type
;
598 N
: Positive := 1) return Inet_Addr_Type
;
599 -- Return N'th addresses in host entry. The first index is 1
601 Host_Error
: exception;
602 -- Exception raised by the two following procedures. Once raised, its
603 -- message contains a string describing the error code. This exception is
604 -- raised when an host entry cannot be retrieved.
606 function Get_Host_By_Address
607 (Address
: Inet_Addr_Type
;
608 Family
: Family_Type
:= Family_Inet
) return Host_Entry_Type
;
609 -- Return host entry structure for the given Inet address. Note that no
610 -- result will be returned if there is no mapping of this IP address to a
611 -- host name in the system tables (host database, DNS or otherwise).
613 function Get_Host_By_Name
614 (Name
: String) return Host_Entry_Type
;
615 -- Return host entry structure for the given host name. Here name is
616 -- either a host name, or an IP address. If Name is an IP address, this
617 -- is equivalent to Get_Host_By_Address (Inet_Addr (Name)).
619 function Host_Name
return String;
620 -- Return the name of the current host
622 type Service_Entry_Type
(Aliases_Length
: Natural) is private;
623 -- Service entries provide complete information on a given service: the
624 -- official name, an array of alternative names or aliases and the port
627 function Official_Name
(S
: Service_Entry_Type
) return String;
628 -- Return official name in service entry
630 function Port_Number
(S
: Service_Entry_Type
) return Port_Type
;
631 -- Return port number in service entry
633 function Protocol_Name
(S
: Service_Entry_Type
) return String;
634 -- Return Protocol in service entry (usually UDP or TCP)
636 function Aliases_Length
(S
: Service_Entry_Type
) return Natural;
637 -- Return number of aliases in service entry
640 (S
: Service_Entry_Type
;
641 N
: Positive := 1) return String;
642 -- Return N'th aliases in service entry (the first index is 1)
644 function Get_Service_By_Name
646 Protocol
: String) return Service_Entry_Type
;
647 -- Return service entry structure for the given service name
649 function Get_Service_By_Port
651 Protocol
: String) return Service_Entry_Type
;
652 -- Return service entry structure for the given service port number
654 Service_Error
: exception;
655 -- Comment required ???
657 -- Errors are described by an enumeration type. There is only one exception
658 -- Socket_Error in this package to deal with an error during a socket
659 -- routine. Once raised, its message contains the error code between
660 -- brackets and a string describing the error code.
662 -- The name of the enumeration constant documents the error condition
663 -- Note that on some platforms, a single error value is used for both
664 -- EWOULDBLOCK and EAGAIN. Both errors are therefore always reported as
665 -- Resource_Temporarily_Unavailable.
670 Address_Already_In_Use
,
671 Cannot_Assign_Requested_Address
,
672 Address_Family_Not_Supported_By_Protocol
,
673 Operation_Already_In_Progress
,
675 Software_Caused_Connection_Abort
,
677 Connection_Reset_By_Peer
,
678 Destination_Address_Required
,
682 Operation_Now_In_Progress
,
683 Interrupted_System_Call
,
686 Transport_Endpoint_Already_Connected
,
687 Too_Many_Symbolic_Links
,
692 Network_Dropped_Connection_Because_Of_Reset
,
693 Network_Is_Unreachable
,
694 No_Buffer_Space_Available
,
695 Protocol_Not_Available
,
696 Transport_Endpoint_Not_Connected
,
697 Socket_Operation_On_Non_Socket
,
698 Operation_Not_Supported
,
699 Protocol_Family_Not_Supported
,
700 Protocol_Not_Supported
,
701 Protocol_Wrong_Type_For_Socket
,
702 Cannot_Send_After_Transport_Endpoint_Shutdown
,
703 Socket_Type_Not_Supported
,
704 Connection_Timed_Out
,
706 Resource_Temporarily_Unavailable
,
709 Host_Name_Lookup_Failure
,
710 Non_Recoverable_Error
,
711 Unknown_Server_Error
,
712 Cannot_Resolve_Error
);
714 -- Get_Socket_Options and Set_Socket_Options manipulate options associated
715 -- with a socket. Options may exist at multiple protocol levels in the
716 -- communication stack. Socket_Level is the uppermost socket level.
720 IP_Protocol_For_IP_Level
,
721 IP_Protocol_For_UDP_Level
,
722 IP_Protocol_For_TCP_Level
);
724 -- There are several options available to manipulate sockets. Each option
725 -- has a name and several values available. Most of the time, the value is
726 -- a boolean to enable or disable this option.
730 Keep_Alive
, -- Enable sending of keep-alive messages
731 Reuse_Address
, -- Allow bind to reuse local address
732 Broadcast
, -- Enable datagram sockets to recv/send broadcasts
733 Send_Buffer
, -- Set/get the maximum socket send buffer in bytes
734 Receive_Buffer
, -- Set/get the maximum socket recv buffer in bytes
735 Linger
, -- Shutdown wait for msg to be sent or timeout occur
736 Error
, -- Get and clear the pending socket error
737 No_Delay
, -- Do not delay send to coalesce data (TCP_NODELAY)
738 Add_Membership
, -- Join a multicast group
739 Drop_Membership
, -- Leave a multicast group
740 Multicast_If
, -- Set default out interface for multicast packets
741 Multicast_TTL
, -- Set the time-to-live of sent multicast packets
742 Multicast_Loop
, -- Sent multicast packets are looped to local socket
743 Receive_Packet_Info
, -- Receive low level packet info as ancillary data
744 Send_Timeout
, -- Set timeout value for output
745 Receive_Timeout
, -- Set timeout value for input
746 Busy_Polling
); -- Set busy polling mode
747 subtype Specific_Option_Name
is
748 Option_Name
range Keep_Alive
.. Option_Name
'Last;
750 type Option_Type
(Name
: Option_Name
:= Keep_Alive
) is record
752 when Generic_Option
=>
753 Optname
: Interfaces
.C
.int
:= -1;
754 Optval
: Interfaces
.C
.int
;
761 Receive_Packet_Info |
773 Microseconds
: Natural;
782 when Add_Membership |
784 Multicast_Address
: Inet_Addr_Type
;
785 Local_Interface
: Inet_Addr_Type
;
788 Outgoing_If
: Inet_Addr_Type
;
790 when Multicast_TTL
=>
791 Time_To_Live
: Natural;
795 Timeout
: Timeval_Duration
;
800 -- There are several controls available to manipulate sockets. Each option
801 -- has a name and several values available. These controls differ from the
802 -- socket options in that they are not specific to sockets but are
803 -- available for any device.
806 (Non_Blocking_IO
, -- Cause a caller not to wait on blocking operations
807 N_Bytes_To_Read
); -- Return the number of bytes available to read
809 type Request_Type
(Name
: Request_Name
:= Non_Blocking_IO
) is record
811 when Non_Blocking_IO
=>
814 when N_Bytes_To_Read
=>
820 -- A request flag allows specification of the type of message transmissions
821 -- or receptions. A request flag can be combination of zero or more
822 -- predefined request flags.
824 type Request_Flag_Type
is private;
826 No_Request_Flag
: constant Request_Flag_Type
;
827 -- This flag corresponds to the normal execution of an operation
829 Process_Out_Of_Band_Data
: constant Request_Flag_Type
;
830 -- This flag requests that the receive or send function operates on
831 -- out-of-band data when the socket supports this notion (e.g.
834 Peek_At_Incoming_Data
: constant Request_Flag_Type
;
835 -- This flag causes the receive operation to return data from the beginning
836 -- of the receive queue without removing that data from the queue. A
837 -- subsequent receive call will return the same data.
839 Wait_For_A_Full_Reception
: constant Request_Flag_Type
;
840 -- This flag requests that the operation block until the full request is
841 -- satisfied. However, the call may still return less data than requested
842 -- if a signal is caught, an error or disconnect occurs, or the next data
843 -- to be received is of a different type than that returned. Note that
844 -- this flag depends on support in the underlying sockets implementation,
845 -- and is not supported under Windows.
847 Send_End_Of_Record
: constant Request_Flag_Type
;
848 -- This flag indicates that the entire message has been sent and so this
849 -- terminates the record.
851 function "+" (L
, R
: Request_Flag_Type
) return Request_Flag_Type
;
852 -- Combine flag L with flag R
854 type Stream_Element_Reference
is access all Ada
.Streams
.Stream_Element
;
856 type Vector_Element
is record
857 Base
: Stream_Element_Reference
;
858 Length
: Interfaces
.C
.size_t
;
861 type Vector_Type
is array (Integer range <>) of Vector_Element
;
863 procedure Create_Socket
864 (Socket
: out Socket_Type
;
865 Family
: Family_Type
:= Family_Inet
;
866 Mode
: Mode_Type
:= Socket_Stream
);
867 -- Create an endpoint for communication. Raises Socket_Error on error
869 procedure Accept_Socket
870 (Server
: Socket_Type
;
871 Socket
: out Socket_Type
;
872 Address
: out Sock_Addr_Type
);
873 -- Extracts the first connection request on the queue of pending
874 -- connections, creates a new connected socket with mostly the same
875 -- properties as Server, and allocates a new socket. The returned Address
876 -- is filled in with the address of the connection. Raises Socket_Error on
877 -- error. Note: if Server is a non-blocking socket, whether or not this
878 -- aspect is inherited by Socket is platform-dependent.
880 procedure Accept_Socket
881 (Server
: Socket_Type
;
882 Socket
: out Socket_Type
;
883 Address
: out Sock_Addr_Type
;
884 Timeout
: Selector_Duration
;
885 Selector
: access Selector_Type
:= null;
886 Status
: out Selector_Status
);
887 -- Accept a new connection on Server using Accept_Socket, waiting no longer
888 -- than the given timeout duration. Status is set to indicate whether the
889 -- operation completed successfully, timed out, or was aborted. If Selector
890 -- is not null, the designated selector is used to wait for the socket to
891 -- become available, else a private selector object is created by this
892 -- procedure and destroyed before it returns.
894 procedure Bind_Socket
895 (Socket
: Socket_Type
;
896 Address
: Sock_Addr_Type
);
897 -- Once a socket is created, assign a local address to it. Raise
898 -- Socket_Error on error.
900 procedure Close_Socket
(Socket
: Socket_Type
);
901 -- Close a socket and more specifically a non-connected socket
903 procedure Connect_Socket
904 (Socket
: Socket_Type
;
905 Server
: Sock_Addr_Type
);
906 -- Make a connection to another socket which has the address of Server.
907 -- Raises Socket_Error on error.
909 procedure Connect_Socket
910 (Socket
: Socket_Type
;
911 Server
: Sock_Addr_Type
;
912 Timeout
: Selector_Duration
;
913 Selector
: access Selector_Type
:= null;
914 Status
: out Selector_Status
);
915 -- Connect Socket to the given Server address using Connect_Socket, waiting
916 -- no longer than the given timeout duration. Status is set to indicate
917 -- whether the operation completed successfully, timed out, or was aborted.
918 -- If Selector is not null, the designated selector is used to wait for the
919 -- socket to become available, else a private selector object is created
920 -- by this procedure and destroyed before it returns. If Timeout is 0.0,
921 -- no attempt is made to detect whether the connection has succeeded; it
922 -- is up to the user to determine this using Check_Selector later on.
924 procedure Control_Socket
925 (Socket
: Socket_Type
;
926 Request
: in out Request_Type
);
927 -- Obtain or set parameter values that control the socket. This control
928 -- differs from the socket options in that they are not specific to sockets
929 -- but are available for any device.
931 function Get_Peer_Name
(Socket
: Socket_Type
) return Sock_Addr_Type
;
932 -- Return the peer or remote socket address of a socket. Raise
933 -- Socket_Error on error.
935 function Get_Socket_Name
(Socket
: Socket_Type
) return Sock_Addr_Type
;
936 -- Return the local or current socket address of a socket. Return
937 -- No_Sock_Addr on error (e.g. socket closed or not locally bound).
939 function Get_Socket_Option
940 (Socket
: Socket_Type
;
941 Level
: Level_Type
:= Socket_Level
;
943 Optname
: Interfaces
.C
.int
:= -1) return Option_Type
;
944 -- Get the options associated with a socket. Raises Socket_Error on error.
945 -- Optname identifies specific option when Name is Generic_Option.
947 procedure Listen_Socket
948 (Socket
: Socket_Type
;
949 Length
: Natural := 15);
950 -- To accept connections, a socket is first created with Create_Socket,
951 -- a willingness to accept incoming connections and a queue Length for
952 -- incoming connections are specified. Raise Socket_Error on error.
953 -- The queue length of 15 is an example value that should be appropriate
954 -- in usual cases. It can be adjusted according to each application's
955 -- particular requirements.
957 procedure Receive_Socket
958 (Socket
: Socket_Type
;
959 Item
: out Ada
.Streams
.Stream_Element_Array
;
960 Last
: out Ada
.Streams
.Stream_Element_Offset
;
961 Flags
: Request_Flag_Type
:= No_Request_Flag
);
962 -- Receive message from Socket. Last is the index value such that Item
963 -- (Last) is the last character assigned. Note that Last is set to
964 -- Item'First - 1 when the socket has been closed by peer. This is not
965 -- an error, and no exception is raised in this case unless Item'First
966 -- is Stream_Element_Offset'First, in which case Constraint_Error is
967 -- raised. Flags allows control of the reception. Raise Socket_Error on
970 procedure Receive_Socket
971 (Socket
: Socket_Type
;
972 Item
: out Ada
.Streams
.Stream_Element_Array
;
973 Last
: out Ada
.Streams
.Stream_Element_Offset
;
974 From
: out Sock_Addr_Type
;
975 Flags
: Request_Flag_Type
:= No_Request_Flag
);
976 -- Receive message from Socket. If Socket is not connection-oriented, the
977 -- source address From of the message is filled in. Last is the index
978 -- value such that Item (Last) is the last character assigned. Flags
979 -- allows control of the reception. Raises Socket_Error on error.
981 procedure Receive_Vector
982 (Socket
: Socket_Type
;
983 Vector
: Vector_Type
;
984 Count
: out Ada
.Streams
.Stream_Element_Count
;
985 Flags
: Request_Flag_Type
:= No_Request_Flag
);
986 -- Receive data from a socket and scatter it into the set of vector
987 -- elements Vector. Count is set to the count of received stream elements.
988 -- Flags allow control over reception.
990 function Resolve_Exception
991 (Occurrence
: Ada
.Exceptions
.Exception_Occurrence
) return Error_Type
;
992 -- When Socket_Error or Host_Error are raised, the exception message
993 -- contains the error code between brackets and a string describing the
994 -- error code. Resolve_Error extracts the error code from an exception
995 -- message and translate it into an enumeration value.
997 procedure Send_Socket
998 (Socket
: Socket_Type
;
999 Item
: Ada
.Streams
.Stream_Element_Array
;
1000 Last
: out Ada
.Streams
.Stream_Element_Offset
;
1001 To
: access Sock_Addr_Type
;
1002 Flags
: Request_Flag_Type
:= No_Request_Flag
);
1003 pragma Inline
(Send_Socket
);
1004 -- Transmit a message over a socket. For a datagram socket, the address
1005 -- is given by To.all. For a stream socket, To must be null. Last
1006 -- is the index value such that Item (Last) is the last character
1007 -- sent. Note that Last is set to Item'First - 1 if the socket has been
1008 -- closed by the peer (unless Item'First is Stream_Element_Offset'First,
1009 -- in which case Constraint_Error is raised instead). This is not an error,
1010 -- and Socket_Error is not raised in that case. Flags allows control of the
1011 -- transmission. Raises exception Socket_Error on error. Note: this
1012 -- subprogram is inlined because it is also used to implement the two
1015 procedure Send_Socket
1016 (Socket
: Socket_Type
;
1017 Item
: Ada
.Streams
.Stream_Element_Array
;
1018 Last
: out Ada
.Streams
.Stream_Element_Offset
;
1019 Flags
: Request_Flag_Type
:= No_Request_Flag
);
1020 -- Transmit a message over a socket. Upon return, Last is set to the index
1021 -- within Item of the last element transmitted. Flags allows control of
1022 -- the transmission. Raises Socket_Error on any detected error condition.
1024 procedure Send_Socket
1025 (Socket
: Socket_Type
;
1026 Item
: Ada
.Streams
.Stream_Element_Array
;
1027 Last
: out Ada
.Streams
.Stream_Element_Offset
;
1028 To
: Sock_Addr_Type
;
1029 Flags
: Request_Flag_Type
:= No_Request_Flag
);
1030 -- Transmit a message over a datagram socket. The destination address is
1031 -- To. Flags allows control of the transmission. Raises Socket_Error on
1034 procedure Send_Vector
1035 (Socket
: Socket_Type
;
1036 Vector
: Vector_Type
;
1037 Count
: out Ada
.Streams
.Stream_Element_Count
;
1038 Flags
: Request_Flag_Type
:= No_Request_Flag
);
1039 -- Transmit data gathered from the set of vector elements Vector to a
1040 -- socket. Count is set to the count of transmitted stream elements. Flags
1041 -- allow control over transmission.
1043 procedure Set_Close_On_Exec
1044 (Socket
: Socket_Type
;
1045 Close_On_Exec
: Boolean;
1046 Status
: out Boolean);
1047 -- When Close_On_Exec is True, mark Socket to be closed automatically when
1048 -- a new program is executed by the calling process (i.e. prevent Socket
1049 -- from being inherited by child processes). When Close_On_Exec is False,
1050 -- mark Socket to not be closed on exec (i.e. allow it to be inherited).
1051 -- Status is False if the operation could not be performed, or is not
1052 -- supported on the target platform.
1054 procedure Set_Socket_Option
1055 (Socket
: Socket_Type
;
1056 Level
: Level_Type
:= Socket_Level
;
1057 Option
: Option_Type
);
1058 -- Manipulate socket options. Raises Socket_Error on error
1060 procedure Shutdown_Socket
1061 (Socket
: Socket_Type
;
1062 How
: Shutmode_Type
:= Shut_Read_Write
);
1063 -- Shutdown a connected socket. If How is Shut_Read further receives will
1064 -- be disallowed. If How is Shut_Write further sends will be disallowed.
1065 -- If How is Shut_Read_Write further sends and receives will be disallowed.
1067 type Stream_Access
is access all Ada
.Streams
.Root_Stream_Type
'Class;
1068 -- Same interface as Ada.Streams.Stream_IO
1070 function Stream
(Socket
: Socket_Type
) return Stream_Access
;
1071 -- Create a stream associated with a connected stream-based socket.
1072 -- Note: keep in mind that the default stream attributes for composite
1073 -- types perform separate Read/Write operations for each component,
1074 -- recursively. If performance is an issue, you may want to consider
1075 -- introducing a buffering stage.
1078 (Socket
: Socket_Type
;
1079 Send_To
: Sock_Addr_Type
) return Stream_Access
;
1080 -- Create a stream associated with an already bound datagram-based socket.
1081 -- Send_To is the destination address to which messages are being sent.
1083 function Get_Address
1084 (Stream
: not null Stream_Access
) return Sock_Addr_Type
;
1085 -- Return the socket address from which the last message was received
1087 procedure Free
is new Ada
.Unchecked_Deallocation
1088 (Ada
.Streams
.Root_Stream_Type
'Class, Stream_Access
);
1089 -- Destroy a stream created by one of the Stream functions above, releasing
1090 -- the corresponding resources. The user is responsible for calling this
1091 -- subprogram when the stream is not needed anymore.
1093 type Socket_Set_Type
is limited private;
1094 -- This type allows manipulation of sets of sockets. It allows waiting
1095 -- for events on multiple endpoints at one time. This type has default
1096 -- initialization, and the default value is the empty set.
1098 -- Note: This type used to contain a pointer to dynamically allocated
1099 -- storage, but this is not the case anymore, and no special precautions
1100 -- are required to avoid memory leaks.
1102 procedure Clear
(Item
: in out Socket_Set_Type
; Socket
: Socket_Type
);
1103 -- Remove Socket from Item
1105 procedure Copy
(Source
: Socket_Set_Type
; Target
: out Socket_Set_Type
);
1106 -- Copy Source into Target as Socket_Set_Type is limited private
1108 procedure Empty
(Item
: out Socket_Set_Type
);
1109 -- Remove all Sockets from Item
1111 procedure Get
(Item
: in out Socket_Set_Type
; Socket
: out Socket_Type
);
1112 -- Extract a Socket from socket set Item. Socket is set to
1113 -- No_Socket when the set is empty.
1115 function Is_Empty
(Item
: Socket_Set_Type
) return Boolean;
1116 -- Return True iff Item is empty
1119 (Item
: Socket_Set_Type
;
1120 Socket
: Socket_Type
) return Boolean;
1121 -- Return True iff Socket is present in Item
1123 procedure Set
(Item
: in out Socket_Set_Type
; Socket
: Socket_Type
);
1124 -- Insert Socket into Item
1126 function Image
(Item
: Socket_Set_Type
) return String;
1127 -- Return a printable image of Item, for debugging purposes
1129 -- The select(2) system call waits for events to occur on any of a set of
1130 -- file descriptors. Usually, three independent sets of descriptors are
1131 -- watched (read, write and exception). A timeout gives an upper bound
1132 -- on the amount of time elapsed before select returns. This function
1133 -- blocks until an event occurs. On some platforms, the select(2) system
1134 -- can block the full process (not just the calling thread).
1136 -- Check_Selector provides the very same behavior. The only difference is
1137 -- that it does not watch for exception events. Note that on some platforms
1138 -- it is kept process blocking on purpose. The timeout parameter allows the
1139 -- user to have the behavior he wants. Abort_Selector allows the safe
1140 -- abort of a blocked Check_Selector call. A special socket is opened by
1141 -- Create_Selector and included in each call to Check_Selector.
1143 -- Abort_Selector causes an event to occur on this descriptor in order to
1144 -- unblock Check_Selector. Note that each call to Abort_Selector will cause
1145 -- exactly one call to Check_Selector to return with Aborted status. The
1146 -- special socket created by Create_Selector is closed when Close_Selector
1149 -- A typical case where it is useful to abort a Check_Selector operation is
1150 -- the situation where a change to the monitored sockets set must be made.
1152 procedure Create_Selector
(Selector
: out Selector_Type
);
1153 -- Initialize (open) a new selector
1155 procedure Close_Selector
(Selector
: in out Selector_Type
);
1156 -- Close Selector and all internal descriptors associated; deallocate any
1157 -- associated resources. This subprogram may be called only when there is
1158 -- no other task still using Selector (i.e. still executing Check_Selector
1159 -- or Abort_Selector on this Selector). Has no effect if Selector is
1162 procedure Check_Selector
1163 (Selector
: Selector_Type
;
1164 R_Socket_Set
: in out Socket_Set_Type
;
1165 W_Socket_Set
: in out Socket_Set_Type
;
1166 Status
: out Selector_Status
;
1167 Timeout
: Selector_Duration
:= Forever
);
1168 -- Return when one Socket in R_Socket_Set has some data to be read or if
1169 -- one Socket in W_Socket_Set is ready to transmit some data. In these
1170 -- cases Status is set to Completed and sockets that are ready are set in
1171 -- R_Socket_Set or W_Socket_Set. Status is set to Expired if no socket was
1172 -- ready after a Timeout expiration. Status is set to Aborted if an abort
1173 -- signal has been received while checking socket status.
1175 -- Note that two different Socket_Set_Type objects must be passed as
1176 -- R_Socket_Set and W_Socket_Set (even if they denote the same set of
1177 -- Sockets), or some event may be lost. Also keep in mind that this
1178 -- procedure modifies the passed socket sets to indicate which sockets
1179 -- actually had events upon return. The socket set therefore has to
1180 -- be reset by the caller for further calls.
1182 -- Socket_Error is raised when the select(2) system call returns an error
1183 -- condition, or when a read error occurs on the signalling socket used for
1184 -- the implementation of Abort_Selector.
1186 procedure Check_Selector
1187 (Selector
: Selector_Type
;
1188 R_Socket_Set
: in out Socket_Set_Type
;
1189 W_Socket_Set
: in out Socket_Set_Type
;
1190 E_Socket_Set
: in out Socket_Set_Type
;
1191 Status
: out Selector_Status
;
1192 Timeout
: Selector_Duration
:= Forever
);
1193 -- This refined version of Check_Selector allows watching for exception
1194 -- events (i.e. notifications of out-of-band transmission and reception).
1195 -- As above, all of R_Socket_Set, W_Socket_Set and E_Socket_Set must be
1196 -- different objects.
1198 procedure Abort_Selector
(Selector
: Selector_Type
);
1199 -- Send an abort signal to the selector. The Selector may not be the
1202 type Fd_Set
is private;
1203 -- ??? This type must not be used directly, it needs to be visible because
1204 -- it is used in the visible part of GNAT.Sockets.Thin_Common. This is
1205 -- really an inversion of abstraction. The private part of GNAT.Sockets
1206 -- needs to have visibility on this type, but since Thin_Common is a child
1207 -- of Sockets, the type can't be declared there. The correct fix would
1208 -- be to move the thin sockets binding outside of GNAT.Sockets altogether,
1209 -- e.g. by renaming it to GNAT.Sockets_Thin.
1213 type Socket_Type
is new Integer;
1214 No_Socket
: constant Socket_Type
:= -1;
1216 -- A selector is either a null selector, which is always "open" and can
1217 -- never be aborted, or a regular selector, which is created "closed",
1218 -- becomes "open" when Create_Selector is called, and "closed" again when
1219 -- Close_Selector is called.
1221 type Selector_Type
(Is_Null
: Boolean := False) is limited record
1227 R_Sig_Socket
: Socket_Type
:= No_Socket
;
1228 W_Sig_Socket
: Socket_Type
:= No_Socket
;
1229 -- Signalling sockets used to abort a select operation
1233 pragma Volatile
(Selector_Type
);
1235 Null_Selector
: constant Selector_Type
:= (Is_Null
=> True);
1238 new System
.Storage_Elements
.Storage_Array
(1 .. SOSC
.SIZEOF_fd_set
);
1239 for Fd_Set
'Alignment use Interfaces
.C
.long
'Alignment;
1240 -- Set conservative alignment so that our Fd_Sets are always adequately
1241 -- aligned for the underlying data type (which is implementation defined
1242 -- and may be an array of C long integers).
1244 type Fd_Set_Access
is access all Fd_Set
;
1245 pragma Convention
(C
, Fd_Set_Access
);
1246 No_Fd_Set_Access
: constant Fd_Set_Access
:= null;
1248 type Socket_Set_Type
is record
1249 Last
: Socket_Type
:= No_Socket
;
1250 -- Highest socket in set. Last = No_Socket denotes an empty set (which
1251 -- is the default initial value).
1253 Set
: aliased Fd_Set
;
1254 -- Underlying socket set. Note that the contents of this component is
1255 -- undefined if Last = No_Socket.
1258 Any_Port
: constant Port_Type
:= 0;
1259 No_Port
: constant Port_Type
:= 0;
1261 Any_Inet_Addr
: constant Inet_Addr_Type
:=
1262 (Family_Inet
, (others => 0));
1263 No_Inet_Addr
: constant Inet_Addr_Type
:=
1264 (Family_Inet
, (others => 0));
1265 Broadcast_Inet_Addr
: constant Inet_Addr_Type
:=
1266 (Family_Inet
, (others => 255));
1267 Loopback_Inet_Addr
: constant Inet_Addr_Type
:=
1268 (Family_Inet
, (127, 0, 0, 1));
1270 Unspecified_Group_Inet_Addr
: constant Inet_Addr_Type
:=
1271 (Family_Inet
, (224, 0, 0, 0));
1272 All_Hosts_Group_Inet_Addr
: constant Inet_Addr_Type
:=
1273 (Family_Inet
, (224, 0, 0, 1));
1274 All_Routers_Group_Inet_Addr
: constant Inet_Addr_Type
:=
1275 (Family_Inet
, (224, 0, 0, 2));
1277 No_Sock_Addr
: constant Sock_Addr_Type
:= (Family_Inet
, No_Inet_Addr
, 0);
1279 Max_Name_Length
: constant := 64;
1280 -- The constant MAXHOSTNAMELEN is usually set to 64
1282 subtype Name_Index
is Natural range 1 .. Max_Name_Length
;
1284 type Name_Type
(Length
: Name_Index
:= Max_Name_Length
) is record
1285 Name
: String (1 .. Length
);
1287 -- We need fixed strings to avoid access types in host entry type
1289 type Name_Array
is array (Natural range <>) of Name_Type
;
1290 type Inet_Addr_Array
is array (Natural range <>) of Inet_Addr_Type
;
1292 type Host_Entry_Type
(Aliases_Length
, Addresses_Length
: Natural) is record
1293 Official
: Name_Type
;
1294 Aliases
: Name_Array
(1 .. Aliases_Length
);
1295 Addresses
: Inet_Addr_Array
(1 .. Addresses_Length
);
1298 type Service_Entry_Type
(Aliases_Length
: Natural) is record
1299 Official
: Name_Type
;
1301 Protocol
: Name_Type
;
1302 Aliases
: Name_Array
(1 .. Aliases_Length
);
1305 type Request_Flag_Type
is mod 2 ** 8;
1306 No_Request_Flag
: constant Request_Flag_Type
:= 0;
1307 Process_Out_Of_Band_Data
: constant Request_Flag_Type
:= 1;
1308 Peek_At_Incoming_Data
: constant Request_Flag_Type
:= 2;
1309 Wait_For_A_Full_Reception
: constant Request_Flag_Type
:= 4;
1310 Send_End_Of_Record
: constant Request_Flag_Type
:= 8;