------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- G N A T . S O C K E T S -- -- -- -- S p e c -- -- -- -- Copyright (C) 2001-2017, AdaCore -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- This package provides an interface to the sockets communication facility -- provided on many operating systems. This is implemented on the following -- platforms: -- All native ports, with restrictions as follows -- Multicast is available only on systems which provide support for this -- feature, so it is not available if Multicast is not supported, or not -- installed. -- VxWorks cross ports fully implement this package -- This package is not yet implemented on LynxOS or other cross ports with Ada.Exceptions; with Ada.Streams; with Ada.Unchecked_Deallocation; with Interfaces.C; with System.OS_Constants; with System.Storage_Elements; package GNAT.Sockets is -- Sockets are designed to provide a consistent communication facility -- between applications. This package provides an Ada binding to the -- de-facto standard BSD sockets API. The documentation below covers -- only the specific binding provided by this package. It assumes that -- the reader is already familiar with general network programming and -- sockets usage. A useful reference on this matter is W. Richard Stevens' -- "UNIX Network Programming: The Sockets Networking API" -- (ISBN: 0131411551). -- GNAT.Sockets has been designed with several ideas in mind -- This is a system independent interface. Therefore, we try as much as -- possible to mask system incompatibilities. Some functionalities are not -- available because there are not fully supported on some systems. -- This is a thick binding. For instance, a major effort has been done to -- avoid using memory addresses or untyped ints. We preferred to define -- streams and enumeration types. Errors are not returned as returned -- values but as exceptions. -- This package provides a POSIX-compliant interface (between two -- different implementations of the same routine, we adopt the one closest -- to the POSIX specification). For instance, using select(), the -- notification of an asynchronous connect failure is delivered in the -- write socket set (POSIX) instead of the exception socket set (NT). -- The example below demonstrates various features of GNAT.Sockets: -- with GNAT.Sockets; use GNAT.Sockets; -- with Ada.Text_IO; -- with Ada.Exceptions; use Ada.Exceptions; -- procedure PingPong is -- Group : constant String := "239.255.128.128"; -- -- Multicast group: administratively scoped IP address -- task Pong is -- entry Start; -- entry Stop; -- end Pong; -- task body Pong is -- Address : Sock_Addr_Type; -- Server : Socket_Type; -- Socket : Socket_Type; -- Channel : Stream_Access; -- begin -- -- Get an Internet address of a host (here the local host name). -- -- Note that a host can have several addresses. Here we get -- -- the first one which is supposed to be the official one. -- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1); -- -- Get a socket address that is an Internet address and a port -- Address.Port := 5876; -- -- The first step is to create a socket. Once created, this -- -- socket must be associated to with an address. Usually only a -- -- server (Pong here) needs to bind an address explicitly. Most -- -- of the time clients can skip this step because the socket -- -- routines will bind an arbitrary address to an unbound socket. -- Create_Socket (Server); -- -- Allow reuse of local addresses -- Set_Socket_Option -- (Server, -- Socket_Level, -- (Reuse_Address, True)); -- Bind_Socket (Server, Address); -- -- A server marks a socket as willing to receive connect events -- Listen_Socket (Server); -- -- Once a server calls Listen_Socket, incoming connects events -- -- can be accepted. The returned Socket is a new socket that -- -- represents the server side of the connection. Server remains -- -- available to receive further connections. -- accept Start; -- Accept_Socket (Server, Socket, Address); -- -- Return a stream associated to the connected socket -- Channel := Stream (Socket); -- -- Force Pong to block -- delay 0.2; -- -- Receive and print message from client Ping -- declare -- Message : String := String'Input (Channel); -- begin -- Ada.Text_IO.Put_Line (Message); -- -- Send same message back to client Ping -- String'Output (Channel, Message); -- end; -- Close_Socket (Server); -- Close_Socket (Socket); -- -- Part of the multicast example -- -- Create a datagram socket to send connectionless, unreliable -- -- messages of a fixed maximum length. -- Create_Socket (Socket, Family_Inet, Socket_Datagram); -- -- Allow reuse of local addresses -- Set_Socket_Option -- (Socket, -- Socket_Level, -- (Reuse_Address, True)); -- -- Controls the live time of the datagram to avoid it being -- -- looped forever due to routing errors. Routers decrement -- -- the TTL of every datagram as it traverses from one network -- -- to another and when its value reaches 0 the packet is -- -- dropped. Default is 1. -- Set_Socket_Option -- (Socket, -- IP_Protocol_For_IP_Level, -- (Multicast_TTL, 1)); -- -- Want the data you send to be looped back to your host -- Set_Socket_Option -- (Socket, -- IP_Protocol_For_IP_Level, -- (Multicast_Loop, True)); -- -- If this socket is intended to receive messages, bind it -- -- to a given socket address. -- Address.Addr := Any_Inet_Addr; -- Address.Port := 55505; -- Bind_Socket (Socket, Address); -- -- Join a multicast group -- -- Portability note: On Windows, this option may be set only -- -- on a bound socket. -- Set_Socket_Option -- (Socket, -- IP_Protocol_For_IP_Level, -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr)); -- -- If this socket is intended to send messages, provide the -- -- receiver socket address. -- Address.Addr := Inet_Addr (Group); -- Address.Port := 55506; -- Channel := Stream (Socket, Address); -- -- Receive and print message from client Ping -- declare -- Message : String := String'Input (Channel); -- begin -- -- Get the address of the sender -- Address := Get_Address (Channel); -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address)); -- -- Send same message back to client Ping -- String'Output (Channel, Message); -- end; -- Close_Socket (Socket); -- accept Stop; -- exception when E : others => -- Ada.Text_IO.Put_Line -- (Exception_Name (E) & ": " & Exception_Message (E)); -- end Pong; -- task Ping is -- entry Start; -- entry Stop; -- end Ping; -- task body Ping is -- Address : Sock_Addr_Type; -- Socket : Socket_Type; -- Channel : Stream_Access; -- begin -- accept Start; -- -- See comments in Ping section for the first steps -- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1); -- Address.Port := 5876; -- Create_Socket (Socket); -- Set_Socket_Option -- (Socket, -- Socket_Level, -- (Reuse_Address, True)); -- -- Force Ping to block -- delay 0.2; -- -- If the client's socket is not bound, Connect_Socket will -- -- bind to an unused address. The client uses Connect_Socket to -- -- create a logical connection between the client's socket and -- -- a server's socket returned by Accept_Socket. -- Connect_Socket (Socket, Address); -- Channel := Stream (Socket); -- -- Send message to server Pong -- String'Output (Channel, "Hello world"); -- -- Force Ping to block -- delay 0.2; -- -- Receive and print message from server Pong -- Ada.Text_IO.Put_Line (String'Input (Channel)); -- Close_Socket (Socket); -- -- Part of multicast example. Code similar to Pong's one -- Create_Socket (Socket, Family_Inet, Socket_Datagram); -- Set_Socket_Option -- (Socket, -- Socket_Level, -- (Reuse_Address, True)); -- Set_Socket_Option -- (Socket, -- IP_Protocol_For_IP_Level, -- (Multicast_TTL, 1)); -- Set_Socket_Option -- (Socket, -- IP_Protocol_For_IP_Level, -- (Multicast_Loop, True)); -- Address.Addr := Any_Inet_Addr; -- Address.Port := 55506; -- Bind_Socket (Socket, Address); -- Set_Socket_Option -- (Socket, -- IP_Protocol_For_IP_Level, -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr)); -- Address.Addr := Inet_Addr (Group); -- Address.Port := 55505; -- Channel := Stream (Socket, Address); -- -- Send message to server Pong -- String'Output (Channel, "Hello world"); -- -- Receive and print message from server Pong -- declare -- Message : String := String'Input (Channel); -- begin -- Address := Get_Address (Channel); -- Ada.Text_IO.Put_Line (Message & " from " & Image (Address)); -- end; -- Close_Socket (Socket); -- accept Stop; -- exception when E : others => -- Ada.Text_IO.Put_Line -- (Exception_Name (E) & ": " & Exception_Message (E)); -- end Ping; -- begin -- Initialize; -- Ping.Start; -- Pong.Start; -- Ping.Stop; -- Pong.Stop; -- Finalize; -- end PingPong; package SOSC renames System.OS_Constants; -- Renaming used to provide short-hand notations throughout the sockets -- binding. Note that System.OS_Constants is an internal unit, and the -- entities declared therein are not meant for direct access by users, -- including through this renaming. use type Interfaces.C.int; -- Need visibility on "-" operator so that we can write -1 procedure Initialize; pragma Obsolescent (Entity => Initialize, Message => "explicit initialization is no longer required"); -- Initialize must be called before using any other socket routines. -- Note that this operation is a no-op on UNIX platforms, but applications -- should make sure to call it if portability is expected: some platforms -- (such as Windows) require initialization before any socket operation. -- This is now a no-op (initialization and finalization are done -- automatically). procedure Initialize (Process_Blocking_IO : Boolean); pragma Obsolescent (Entity => Initialize, Message => "passing a parameter to Initialize is no longer supported"); -- Previous versions of GNAT.Sockets used to require the user to indicate -- whether socket I/O was process- or thread-blocking on the platform. -- This property is now determined automatically when the run-time library -- is built. The old version of Initialize, taking a parameter, is kept -- for compatibility reasons, but this interface is obsolete (and if the -- value given is wrong, an exception will be raised at run time). -- This is now a no-op (initialization and finalization are done -- automatically). procedure Finalize; pragma Obsolescent (Entity => Finalize, Message => "explicit finalization is no longer required"); -- After Finalize is called it is not possible to use any routines -- exported in by this package. This procedure is idempotent. -- This is now a no-op (initialization and finalization are done -- automatically). type Socket_Type is private; -- Sockets are used to implement a reliable bi-directional point-to-point, -- stream-based connections between hosts. No_Socket provides a special -- value to denote uninitialized sockets. No_Socket : constant Socket_Type; type Selector_Type is limited private; type Selector_Access is access all Selector_Type; -- Selector objects are used to wait for i/o events to occur on sockets Null_Selector : constant Selector_Type; -- The Null_Selector can be used in place of a normal selector without -- having to call Create_Selector if the use of Abort_Selector is not -- required. -- Timeval_Duration is a subtype of Standard.Duration because the full -- range of Standard.Duration cannot be represented in the equivalent C -- structure (struct timeval). Moreover, negative values are not allowed -- to avoid system incompatibilities. Immediate : constant Duration := 0.0; Forever : constant Duration := Duration'Min (Duration'Last, 1.0 * SOSC.MAX_tv_sec); -- Largest possible Duration that is also a valid value for struct timeval subtype Timeval_Duration is Duration range Immediate .. Forever; subtype Selector_Duration is Timeval_Duration; -- Timeout value for selector operations type Selector_Status is (Completed, Expired, Aborted); -- Completion status of a selector operation, indicated as follows: -- Complete: one of the expected events occurred -- Expired: no event occurred before the expiration of the timeout -- Aborted: an external action cancelled the wait operation before -- any event occurred. Socket_Error : exception; -- There is only one exception in this package to deal with an error during -- a socket routine. Once raised, its message contains a string describing -- the error code. function Image (Socket : Socket_Type) return String; -- Return a printable string for Socket function To_C (Socket : Socket_Type) return Integer; -- Return a file descriptor to be used by external subprograms. This is -- useful for C functions that are not yet interfaced in this package. type Family_Type is (Family_Inet, Family_Inet6); -- Address family (or protocol family) identifies the communication domain -- and groups protocols with similar address formats. type Mode_Type is (Socket_Stream, Socket_Datagram); -- Stream sockets provide connection-oriented byte streams. Datagram -- sockets support unreliable connectionless message based communication. type Shutmode_Type is (Shut_Read, Shut_Write, Shut_Read_Write); -- When a process closes a socket, the policy is to retain any data queued -- until either a delivery or a timeout expiration (in this case, the data -- are discarded). A finer control is available through shutdown. With -- Shut_Read, no more data can be received from the socket. With_Write, no -- more data can be transmitted. Neither transmission nor reception can be -- performed with Shut_Read_Write. type Port_Type is range 0 .. 16#ffff#; -- TCP/UDP port number Any_Port : constant Port_Type; -- All ports No_Port : constant Port_Type; -- Uninitialized port number type Inet_Addr_Type (Family : Family_Type := Family_Inet) is private; -- An Internet address depends on an address family (IPv4 contains 4 octets -- and IPv6 contains 16 octets). Any_Inet_Addr is a special value treated -- like a wildcard enabling all addresses. No_Inet_Addr provides a special -- value to denote uninitialized inet addresses. Any_Inet_Addr : constant Inet_Addr_Type; No_Inet_Addr : constant Inet_Addr_Type; Broadcast_Inet_Addr : constant Inet_Addr_Type; Loopback_Inet_Addr : constant Inet_Addr_Type; -- Useful constants for IPv4 multicast addresses Unspecified_Group_Inet_Addr : constant Inet_Addr_Type; All_Hosts_Group_Inet_Addr : constant Inet_Addr_Type; All_Routers_Group_Inet_Addr : constant Inet_Addr_Type; type Sock_Addr_Type (Family : Family_Type := Family_Inet) is record Addr : Inet_Addr_Type (Family); Port : Port_Type; end record; -- Socket addresses fully define a socket connection with protocol family, -- an Internet address and a port. No_Sock_Addr provides a special value -- for uninitialized socket addresses. No_Sock_Addr : constant Sock_Addr_Type; function Image (Value : Inet_Addr_Type) return String; -- Return an image of an Internet address. IPv4 notation consists in 4 -- octets in decimal format separated by dots. IPv6 notation consists in -- 16 octets in hexadecimal format separated by colons (and possibly -- dots). function Image (Value : Sock_Addr_Type) return String; -- Return inet address image and port image separated by a colon function Inet_Addr (Image : String) return Inet_Addr_Type; -- Convert address image from numbers-and-dots notation into an -- inet address. -- Host entries provide complete information on a given host: the official -- name, an array of alternative names or aliases and array of network -- addresses. type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is private; function Official_Name (E : Host_Entry_Type) return String; -- Return official name in host entry function Aliases_Length (E : Host_Entry_Type) return Natural; -- Return number of aliases in host entry function Addresses_Length (E : Host_Entry_Type) return Natural; -- Return number of addresses in host entry function Aliases (E : Host_Entry_Type; N : Positive := 1) return String; -- Return N'th aliases in host entry. The first index is 1 function Addresses (E : Host_Entry_Type; N : Positive := 1) return Inet_Addr_Type; -- Return N'th addresses in host entry. The first index is 1 Host_Error : exception; -- Exception raised by the two following procedures. Once raised, its -- message contains a string describing the error code. This exception is -- raised when an host entry cannot be retrieved. function Get_Host_By_Address (Address : Inet_Addr_Type; Family : Family_Type := Family_Inet) return Host_Entry_Type; -- Return host entry structure for the given Inet address. Note that no -- result will be returned if there is no mapping of this IP address to a -- host name in the system tables (host database, DNS or otherwise). function Get_Host_By_Name (Name : String) return Host_Entry_Type; -- Return host entry structure for the given host name. Here name is -- either a host name, or an IP address. If Name is an IP address, this -- is equivalent to Get_Host_By_Address (Inet_Addr (Name)). function Host_Name return String; -- Return the name of the current host type Service_Entry_Type (Aliases_Length : Natural) is private; -- Service entries provide complete information on a given service: the -- official name, an array of alternative names or aliases and the port -- number. function Official_Name (S : Service_Entry_Type) return String; -- Return official name in service entry function Port_Number (S : Service_Entry_Type) return Port_Type; -- Return port number in service entry function Protocol_Name (S : Service_Entry_Type) return String; -- Return Protocol in service entry (usually UDP or TCP) function Aliases_Length (S : Service_Entry_Type) return Natural; -- Return number of aliases in service entry function Aliases (S : Service_Entry_Type; N : Positive := 1) return String; -- Return N'th aliases in service entry (the first index is 1) function Get_Service_By_Name (Name : String; Protocol : String) return Service_Entry_Type; -- Return service entry structure for the given service name function Get_Service_By_Port (Port : Port_Type; Protocol : String) return Service_Entry_Type; -- Return service entry structure for the given service port number Service_Error : exception; -- Comment required ??? -- Errors are described by an enumeration type. There is only one exception -- Socket_Error in this package to deal with an error during a socket -- routine. Once raised, its message contains the error code between -- brackets and a string describing the error code. -- The name of the enumeration constant documents the error condition -- Note that on some platforms, a single error value is used for both -- EWOULDBLOCK and EAGAIN. Both errors are therefore always reported as -- Resource_Temporarily_Unavailable. type Error_Type is (Success, Permission_Denied, Address_Already_In_Use, Cannot_Assign_Requested_Address, Address_Family_Not_Supported_By_Protocol, Operation_Already_In_Progress, Bad_File_Descriptor, Software_Caused_Connection_Abort, Connection_Refused, Connection_Reset_By_Peer, Destination_Address_Required, Bad_Address, Host_Is_Down, No_Route_To_Host, Operation_Now_In_Progress, Interrupted_System_Call, Invalid_Argument, Input_Output_Error, Transport_Endpoint_Already_Connected, Too_Many_Symbolic_Links, Too_Many_Open_Files, Message_Too_Long, File_Name_Too_Long, Network_Is_Down, Network_Dropped_Connection_Because_Of_Reset, Network_Is_Unreachable, No_Buffer_Space_Available, Protocol_Not_Available, Transport_Endpoint_Not_Connected, Socket_Operation_On_Non_Socket, Operation_Not_Supported, Protocol_Family_Not_Supported, Protocol_Not_Supported, Protocol_Wrong_Type_For_Socket, Cannot_Send_After_Transport_Endpoint_Shutdown, Socket_Type_Not_Supported, Connection_Timed_Out, Too_Many_References, Resource_Temporarily_Unavailable, Broken_Pipe, Unknown_Host, Host_Name_Lookup_Failure, Non_Recoverable_Error, Unknown_Server_Error, Cannot_Resolve_Error); -- Get_Socket_Options and Set_Socket_Options manipulate options associated -- with a socket. Options may exist at multiple protocol levels in the -- communication stack. Socket_Level is the uppermost socket level. type Level_Type is (Socket_Level, IP_Protocol_For_IP_Level, IP_Protocol_For_UDP_Level, IP_Protocol_For_TCP_Level); -- There are several options available to manipulate sockets. Each option -- has a name and several values available. Most of the time, the value is -- a boolean to enable or disable this option. type Option_Name is (Generic_Option, Keep_Alive, -- Enable sending of keep-alive messages Reuse_Address, -- Allow bind to reuse local address Broadcast, -- Enable datagram sockets to recv/send broadcasts Send_Buffer, -- Set/get the maximum socket send buffer in bytes Receive_Buffer, -- Set/get the maximum socket recv buffer in bytes Linger, -- Shutdown wait for msg to be sent or timeout occur Error, -- Get and clear the pending socket error No_Delay, -- Do not delay send to coalesce data (TCP_NODELAY) Add_Membership, -- Join a multicast group Drop_Membership, -- Leave a multicast group Multicast_If, -- Set default out interface for multicast packets Multicast_TTL, -- Set the time-to-live of sent multicast packets Multicast_Loop, -- Sent multicast packets are looped to local socket Receive_Packet_Info, -- Receive low level packet info as ancillary data Send_Timeout, -- Set timeout value for output Receive_Timeout, -- Set timeout value for input Busy_Polling); -- Set busy polling mode subtype Specific_Option_Name is Option_Name range Keep_Alive .. Option_Name'Last; type Option_Type (Name : Option_Name := Keep_Alive) is record case Name is when Generic_Option => Optname : Interfaces.C.int := -1; Optval : Interfaces.C.int; when Keep_Alive | Reuse_Address | Broadcast | Linger | No_Delay | Receive_Packet_Info | Multicast_Loop => Enabled : Boolean; case Name is when Linger => Seconds : Natural; when others => null; end case; when Busy_Polling => Microseconds : Natural; when Send_Buffer | Receive_Buffer => Size : Natural; when Error => Error : Error_Type; when Add_Membership | Drop_Membership => Multicast_Address : Inet_Addr_Type; Local_Interface : Inet_Addr_Type; when Multicast_If => Outgoing_If : Inet_Addr_Type; when Multicast_TTL => Time_To_Live : Natural; when Send_Timeout | Receive_Timeout => Timeout : Timeval_Duration; end case; end record; -- There are several controls available to manipulate sockets. Each option -- has a name and several values available. These controls differ from the -- socket options in that they are not specific to sockets but are -- available for any device. type Request_Name is (Non_Blocking_IO, -- Cause a caller not to wait on blocking operations N_Bytes_To_Read); -- Return the number of bytes available to read type Request_Type (Name : Request_Name := Non_Blocking_IO) is record case Name is when Non_Blocking_IO => Enabled : Boolean; when N_Bytes_To_Read => Size : Natural; end case; end record; -- A request flag allows specification of the type of message transmissions -- or receptions. A request flag can be combination of zero or more -- predefined request flags. type Request_Flag_Type is private; No_Request_Flag : constant Request_Flag_Type; -- This flag corresponds to the normal execution of an operation Process_Out_Of_Band_Data : constant Request_Flag_Type; -- This flag requests that the receive or send function operates on -- out-of-band data when the socket supports this notion (e.g. -- Socket_Stream). Peek_At_Incoming_Data : constant Request_Flag_Type; -- This flag causes the receive operation to return data from the beginning -- of the receive queue without removing that data from the queue. A -- subsequent receive call will return the same data. Wait_For_A_Full_Reception : constant Request_Flag_Type; -- This flag requests that the operation block until the full request is -- satisfied. However, the call may still return less data than requested -- if a signal is caught, an error or disconnect occurs, or the next data -- to be received is of a different type than that returned. Note that -- this flag depends on support in the underlying sockets implementation, -- and is not supported under Windows. Send_End_Of_Record : constant Request_Flag_Type; -- This flag indicates that the entire message has been sent and so this -- terminates the record. function "+" (L, R : Request_Flag_Type) return Request_Flag_Type; -- Combine flag L with flag R type Stream_Element_Reference is access all Ada.Streams.Stream_Element; type Vector_Element is record Base : Stream_Element_Reference; Length : Interfaces.C.size_t; end record; type Vector_Type is array (Integer range <>) of Vector_Element; procedure Create_Socket (Socket : out Socket_Type; Family : Family_Type := Family_Inet; Mode : Mode_Type := Socket_Stream); -- Create an endpoint for communication. Raises Socket_Error on error procedure Accept_Socket (Server : Socket_Type; Socket : out Socket_Type; Address : out Sock_Addr_Type); -- Extracts the first connection request on the queue of pending -- connections, creates a new connected socket with mostly the same -- properties as Server, and allocates a new socket. The returned Address -- is filled in with the address of the connection. Raises Socket_Error on -- error. Note: if Server is a non-blocking socket, whether or not this -- aspect is inherited by Socket is platform-dependent. procedure Accept_Socket (Server : Socket_Type; Socket : out Socket_Type; Address : out Sock_Addr_Type; Timeout : Selector_Duration; Selector : access Selector_Type := null; Status : out Selector_Status); -- Accept a new connection on Server using Accept_Socket, waiting no longer -- than the given timeout duration. Status is set to indicate whether the -- operation completed successfully, timed out, or was aborted. If Selector -- is not null, the designated selector is used to wait for the socket to -- become available, else a private selector object is created by this -- procedure and destroyed before it returns. procedure Bind_Socket (Socket : Socket_Type; Address : Sock_Addr_Type); -- Once a socket is created, assign a local address to it. Raise -- Socket_Error on error. procedure Close_Socket (Socket : Socket_Type); -- Close a socket and more specifically a non-connected socket procedure Connect_Socket (Socket : Socket_Type; Server : Sock_Addr_Type); -- Make a connection to another socket which has the address of Server. -- Raises Socket_Error on error. procedure Connect_Socket (Socket : Socket_Type; Server : Sock_Addr_Type; Timeout : Selector_Duration; Selector : access Selector_Type := null; Status : out Selector_Status); -- Connect Socket to the given Server address using Connect_Socket, waiting -- no longer than the given timeout duration. Status is set to indicate -- whether the operation completed successfully, timed out, or was aborted. -- If Selector is not null, the designated selector is used to wait for the -- socket to become available, else a private selector object is created -- by this procedure and destroyed before it returns. If Timeout is 0.0, -- no attempt is made to detect whether the connection has succeeded; it -- is up to the user to determine this using Check_Selector later on. procedure Control_Socket (Socket : Socket_Type; Request : in out Request_Type); -- Obtain or set parameter values that control the socket. This control -- differs from the socket options in that they are not specific to sockets -- but are available for any device. function Get_Peer_Name (Socket : Socket_Type) return Sock_Addr_Type; -- Return the peer or remote socket address of a socket. Raise -- Socket_Error on error. function Get_Socket_Name (Socket : Socket_Type) return Sock_Addr_Type; -- Return the local or current socket address of a socket. Return -- No_Sock_Addr on error (e.g. socket closed or not locally bound). function Get_Socket_Option (Socket : Socket_Type; Level : Level_Type := Socket_Level; Name : Option_Name; Optname : Interfaces.C.int := -1) return Option_Type; -- Get the options associated with a socket. Raises Socket_Error on error. -- Optname identifies specific option when Name is Generic_Option. procedure Listen_Socket (Socket : Socket_Type; Length : Natural := 15); -- To accept connections, a socket is first created with Create_Socket, -- a willingness to accept incoming connections and a queue Length for -- incoming connections are specified. Raise Socket_Error on error. -- The queue length of 15 is an example value that should be appropriate -- in usual cases. It can be adjusted according to each application's -- particular requirements. procedure Receive_Socket (Socket : Socket_Type; Item : out Ada.Streams.Stream_Element_Array; Last : out Ada.Streams.Stream_Element_Offset; Flags : Request_Flag_Type := No_Request_Flag); -- Receive message from Socket. Last is the index value such that Item -- (Last) is the last character assigned. Note that Last is set to -- Item'First - 1 when the socket has been closed by peer. This is not -- an error, and no exception is raised in this case unless Item'First -- is Stream_Element_Offset'First, in which case Constraint_Error is -- raised. Flags allows control of the reception. Raise Socket_Error on -- error. procedure Receive_Socket (Socket : Socket_Type; Item : out Ada.Streams.Stream_Element_Array; Last : out Ada.Streams.Stream_Element_Offset; From : out Sock_Addr_Type; Flags : Request_Flag_Type := No_Request_Flag); -- Receive message from Socket. If Socket is not connection-oriented, the -- source address From of the message is filled in. Last is the index -- value such that Item (Last) is the last character assigned. Flags -- allows control of the reception. Raises Socket_Error on error. procedure Receive_Vector (Socket : Socket_Type; Vector : Vector_Type; Count : out Ada.Streams.Stream_Element_Count; Flags : Request_Flag_Type := No_Request_Flag); -- Receive data from a socket and scatter it into the set of vector -- elements Vector. Count is set to the count of received stream elements. -- Flags allow control over reception. function Resolve_Exception (Occurrence : Ada.Exceptions.Exception_Occurrence) return Error_Type; -- When Socket_Error or Host_Error are raised, the exception message -- contains the error code between brackets and a string describing the -- error code. Resolve_Error extracts the error code from an exception -- message and translate it into an enumeration value. procedure Send_Socket (Socket : Socket_Type; Item : Ada.Streams.Stream_Element_Array; Last : out Ada.Streams.Stream_Element_Offset; To : access Sock_Addr_Type; Flags : Request_Flag_Type := No_Request_Flag); pragma Inline (Send_Socket); -- Transmit a message over a socket. For a datagram socket, the address -- is given by To.all. For a stream socket, To must be null. Last -- is the index value such that Item (Last) is the last character -- sent. Note that Last is set to Item'First - 1 if the socket has been -- closed by the peer (unless Item'First is Stream_Element_Offset'First, -- in which case Constraint_Error is raised instead). This is not an error, -- and Socket_Error is not raised in that case. Flags allows control of the -- transmission. Raises exception Socket_Error on error. Note: this -- subprogram is inlined because it is also used to implement the two -- variants below. procedure Send_Socket (Socket : Socket_Type; Item : Ada.Streams.Stream_Element_Array; Last : out Ada.Streams.Stream_Element_Offset; Flags : Request_Flag_Type := No_Request_Flag); -- Transmit a message over a socket. Upon return, Last is set to the index -- within Item of the last element transmitted. Flags allows control of -- the transmission. Raises Socket_Error on any detected error condition. procedure Send_Socket (Socket : Socket_Type; Item : Ada.Streams.Stream_Element_Array; Last : out Ada.Streams.Stream_Element_Offset; To : Sock_Addr_Type; Flags : Request_Flag_Type := No_Request_Flag); -- Transmit a message over a datagram socket. The destination address is -- To. Flags allows control of the transmission. Raises Socket_Error on -- error. procedure Send_Vector (Socket : Socket_Type; Vector : Vector_Type; Count : out Ada.Streams.Stream_Element_Count; Flags : Request_Flag_Type := No_Request_Flag); -- Transmit data gathered from the set of vector elements Vector to a -- socket. Count is set to the count of transmitted stream elements. Flags -- allow control over transmission. procedure Set_Close_On_Exec (Socket : Socket_Type; Close_On_Exec : Boolean; Status : out Boolean); -- When Close_On_Exec is True, mark Socket to be closed automatically when -- a new program is executed by the calling process (i.e. prevent Socket -- from being inherited by child processes). When Close_On_Exec is False, -- mark Socket to not be closed on exec (i.e. allow it to be inherited). -- Status is False if the operation could not be performed, or is not -- supported on the target platform. procedure Set_Socket_Option (Socket : Socket_Type; Level : Level_Type := Socket_Level; Option : Option_Type); -- Manipulate socket options. Raises Socket_Error on error procedure Shutdown_Socket (Socket : Socket_Type; How : Shutmode_Type := Shut_Read_Write); -- Shutdown a connected socket. If How is Shut_Read further receives will -- be disallowed. If How is Shut_Write further sends will be disallowed. -- If How is Shut_Read_Write further sends and receives will be disallowed. type Stream_Access is access all Ada.Streams.Root_Stream_Type'Class; -- Same interface as Ada.Streams.Stream_IO function Stream (Socket : Socket_Type) return Stream_Access; -- Create a stream associated with a connected stream-based socket. -- Note: keep in mind that the default stream attributes for composite -- types perform separate Read/Write operations for each component, -- recursively. If performance is an issue, you may want to consider -- introducing a buffering stage. function Stream (Socket : Socket_Type; Send_To : Sock_Addr_Type) return Stream_Access; -- Create a stream associated with an already bound datagram-based socket. -- Send_To is the destination address to which messages are being sent. function Get_Address (Stream : not null Stream_Access) return Sock_Addr_Type; -- Return the socket address from which the last message was received procedure Free is new Ada.Unchecked_Deallocation (Ada.Streams.Root_Stream_Type'Class, Stream_Access); -- Destroy a stream created by one of the Stream functions above, releasing -- the corresponding resources. The user is responsible for calling this -- subprogram when the stream is not needed anymore. type Socket_Set_Type is limited private; -- This type allows manipulation of sets of sockets. It allows waiting -- for events on multiple endpoints at one time. This type has default -- initialization, and the default value is the empty set. -- -- Note: This type used to contain a pointer to dynamically allocated -- storage, but this is not the case anymore, and no special precautions -- are required to avoid memory leaks. procedure Clear (Item : in out Socket_Set_Type; Socket : Socket_Type); -- Remove Socket from Item procedure Copy (Source : Socket_Set_Type; Target : out Socket_Set_Type); -- Copy Source into Target as Socket_Set_Type is limited private procedure Empty (Item : out Socket_Set_Type); -- Remove all Sockets from Item procedure Get (Item : in out Socket_Set_Type; Socket : out Socket_Type); -- Extract a Socket from socket set Item. Socket is set to -- No_Socket when the set is empty. function Is_Empty (Item : Socket_Set_Type) return Boolean; -- Return True iff Item is empty function Is_Set (Item : Socket_Set_Type; Socket : Socket_Type) return Boolean; -- Return True iff Socket is present in Item procedure Set (Item : in out Socket_Set_Type; Socket : Socket_Type); -- Insert Socket into Item function Image (Item : Socket_Set_Type) return String; -- Return a printable image of Item, for debugging purposes -- The select(2) system call waits for events to occur on any of a set of -- file descriptors. Usually, three independent sets of descriptors are -- watched (read, write and exception). A timeout gives an upper bound -- on the amount of time elapsed before select returns. This function -- blocks until an event occurs. On some platforms, the select(2) system -- can block the full process (not just the calling thread). -- -- Check_Selector provides the very same behavior. The only difference is -- that it does not watch for exception events. Note that on some platforms -- it is kept process blocking on purpose. The timeout parameter allows the -- user to have the behavior he wants. Abort_Selector allows the safe -- abort of a blocked Check_Selector call. A special socket is opened by -- Create_Selector and included in each call to Check_Selector. -- -- Abort_Selector causes an event to occur on this descriptor in order to -- unblock Check_Selector. Note that each call to Abort_Selector will cause -- exactly one call to Check_Selector to return with Aborted status. The -- special socket created by Create_Selector is closed when Close_Selector -- is called. -- -- A typical case where it is useful to abort a Check_Selector operation is -- the situation where a change to the monitored sockets set must be made. procedure Create_Selector (Selector : out Selector_Type); -- Initialize (open) a new selector procedure Close_Selector (Selector : in out Selector_Type); -- Close Selector and all internal descriptors associated; deallocate any -- associated resources. This subprogram may be called only when there is -- no other task still using Selector (i.e. still executing Check_Selector -- or Abort_Selector on this Selector). Has no effect if Selector is -- already closed. procedure Check_Selector (Selector : Selector_Type; R_Socket_Set : in out Socket_Set_Type; W_Socket_Set : in out Socket_Set_Type; Status : out Selector_Status; Timeout : Selector_Duration := Forever); -- Return when one Socket in R_Socket_Set has some data to be read or if -- one Socket in W_Socket_Set is ready to transmit some data. In these -- cases Status is set to Completed and sockets that are ready are set in -- R_Socket_Set or W_Socket_Set. Status is set to Expired if no socket was -- ready after a Timeout expiration. Status is set to Aborted if an abort -- signal has been received while checking socket status. -- -- Note that two different Socket_Set_Type objects must be passed as -- R_Socket_Set and W_Socket_Set (even if they denote the same set of -- Sockets), or some event may be lost. Also keep in mind that this -- procedure modifies the passed socket sets to indicate which sockets -- actually had events upon return. The socket set therefore has to -- be reset by the caller for further calls. -- -- Socket_Error is raised when the select(2) system call returns an error -- condition, or when a read error occurs on the signalling socket used for -- the implementation of Abort_Selector. procedure Check_Selector (Selector : Selector_Type; R_Socket_Set : in out Socket_Set_Type; W_Socket_Set : in out Socket_Set_Type; E_Socket_Set : in out Socket_Set_Type; Status : out Selector_Status; Timeout : Selector_Duration := Forever); -- This refined version of Check_Selector allows watching for exception -- events (i.e. notifications of out-of-band transmission and reception). -- As above, all of R_Socket_Set, W_Socket_Set and E_Socket_Set must be -- different objects. procedure Abort_Selector (Selector : Selector_Type); -- Send an abort signal to the selector. The Selector may not be the -- Null_Selector. type Fd_Set is private; -- ??? This type must not be used directly, it needs to be visible because -- it is used in the visible part of GNAT.Sockets.Thin_Common. This is -- really an inversion of abstraction. The private part of GNAT.Sockets -- needs to have visibility on this type, but since Thin_Common is a child -- of Sockets, the type can't be declared there. The correct fix would -- be to move the thin sockets binding outside of GNAT.Sockets altogether, -- e.g. by renaming it to GNAT.Sockets_Thin. private type Socket_Type is new Integer; No_Socket : constant Socket_Type := -1; -- A selector is either a null selector, which is always "open" and can -- never be aborted, or a regular selector, which is created "closed", -- becomes "open" when Create_Selector is called, and "closed" again when -- Close_Selector is called. type Selector_Type (Is_Null : Boolean := False) is limited record case Is_Null is when True => null; when False => R_Sig_Socket : Socket_Type := No_Socket; W_Sig_Socket : Socket_Type := No_Socket; -- Signalling sockets used to abort a select operation end case; end record; pragma Volatile (Selector_Type); Null_Selector : constant Selector_Type := (Is_Null => True); type Fd_Set is new System.Storage_Elements.Storage_Array (1 .. SOSC.SIZEOF_fd_set); for Fd_Set'Alignment use Interfaces.C.long'Alignment; -- Set conservative alignment so that our Fd_Sets are always adequately -- aligned for the underlying data type (which is implementation defined -- and may be an array of C long integers). type Fd_Set_Access is access all Fd_Set; pragma Convention (C, Fd_Set_Access); No_Fd_Set_Access : constant Fd_Set_Access := null; type Socket_Set_Type is record Last : Socket_Type := No_Socket; -- Highest socket in set. Last = No_Socket denotes an empty set (which -- is the default initial value). Set : aliased Fd_Set; -- Underlying socket set. Note that the contents of this component is -- undefined if Last = No_Socket. end record; subtype Inet_Addr_Comp_Type is Natural range 0 .. 255; -- Octet for Internet address type Inet_Addr_VN_Type is array (Natural range <>) of Inet_Addr_Comp_Type; subtype Inet_Addr_V4_Type is Inet_Addr_VN_Type (1 .. 4); subtype Inet_Addr_V6_Type is Inet_Addr_VN_Type (1 .. 16); type Inet_Addr_Type (Family : Family_Type := Family_Inet) is record case Family is when Family_Inet => Sin_V4 : Inet_Addr_V4_Type := (others => 0); when Family_Inet6 => Sin_V6 : Inet_Addr_V6_Type := (others => 0); end case; end record; Any_Port : constant Port_Type := 0; No_Port : constant Port_Type := 0; Any_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (others => 0)); No_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (others => 0)); Broadcast_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (others => 255)); Loopback_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (127, 0, 0, 1)); Unspecified_Group_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (224, 0, 0, 0)); All_Hosts_Group_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (224, 0, 0, 1)); All_Routers_Group_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (224, 0, 0, 2)); No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0); Max_Name_Length : constant := 64; -- The constant MAXHOSTNAMELEN is usually set to 64 subtype Name_Index is Natural range 1 .. Max_Name_Length; type Name_Type (Length : Name_Index := Max_Name_Length) is record Name : String (1 .. Length); end record; -- We need fixed strings to avoid access types in host entry type type Name_Array is array (Natural range <>) of Name_Type; type Inet_Addr_Array is array (Natural range <>) of Inet_Addr_Type; type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is record Official : Name_Type; Aliases : Name_Array (1 .. Aliases_Length); Addresses : Inet_Addr_Array (1 .. Addresses_Length); end record; type Service_Entry_Type (Aliases_Length : Natural) is record Official : Name_Type; Port : Port_Type; Protocol : Name_Type; Aliases : Name_Array (1 .. Aliases_Length); end record; type Request_Flag_Type is mod 2 ** 8; No_Request_Flag : constant Request_Flag_Type := 0; Process_Out_Of_Band_Data : constant Request_Flag_Type := 1; Peek_At_Incoming_Data : constant Request_Flag_Type := 2; Wait_For_A_Full_Reception : constant Request_Flag_Type := 4; Send_End_Of_Record : constant Request_Flag_Type := 8; end GNAT.Sockets;