Re: Making a Inet_Addr_Type out of octects (GNAT.Sockets)

[anon@anon.org (anon)]

if you mean "4 octects" is 4 byte array, then
with GNAT.Sockets.Thin ;
use  GNAT.Sockets.Thin ;

        Bytes    : array ( 0..3 ) of Interfaces.C.unsigned_char;
        Sin_Addr : In_Addr ;

        Sin_Addr.S_B1 := Bytes ( 0 ) ;
        Sin_Addr.S_B2 := Bytes ( 1 ) ;
        Sin_Addr.S_B3 := Bytes ( 2 ) ;
        Sin_Addr.S_B4 := Bytes ( 3 ) ;


-- located with in GNAT.Socket package

with GNAT.Sockets.Thin ;
use  GNAT.Sockets.Thin ;

      Sin : aliased Sockaddr_In ;

      Sin.Sin_Addr.S_B1 := 127 ; 
      Sin.Sin_Addr.S_B2 := 0 ;
      Sin.Sin_Addr.S_B3 := 0 ;
      Sin.Sin_Addr.S_B4 := 1 ;


Then there a string version:

    with GNAT.Sockets ;
    use  GNAT.Sockets ;

    localhost : constant Inet_Addr_Type := Inet_Addr ( "127.0.0.1" ) ;


As for "Inet_Addr_Type" it is defined in in GNAT.Sockets
copy edit out Family_Inet6 ( IPv6 ). Following is copied from 
GNAT.Sockets.ads .

   type Family_Type is (Family_Inet, Family_Inet6);

   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.

   Broadcast_Inet_Addr : constant Inet_Addr_Type;

private


   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;


   -- set address value to IPv4 "255.255.255.255"

   Broadcast_Inet_Addr : constant Inet_Addr_Type :=
                           (Family_Inet, (others => 255)); 



In <joPGk.376724$yE1.161337@attbi_s21>, "Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org> writes:
>mockturtle wrote:
>> 
>> I have 4 octects (read by a received packet) which rappresent
>> an IP address and  I want to convert them into a Inet_Addr_Type
>> (using GNAT.Sockets). Of course I could convert the 4 octects
>> into a string to be given to function Inet_Addr_Type, but it seems
>> a bit "convoluted" (it sounds like the joke about the mathematician's
>> algorithm to make a pot of hot water :-).   My question is: there
>> is a  function which  allows me to do such a conversion in a
>> more direct way? I looked at g-sockets, searching for
>> "Inet_Addr_Type", but I could not  find anything.
>
>I'm not aware of any way provided by the pkg other than that you outlined above.
>
>There are ways using Unchecked_Conversion and address overlays, but they are Not 
>Recommended.
>
>-- 
>Jeff Carter
>"My legs are gray, my ears are gnarled, my eyes are old and bent."
>Monty Python's Life of Brian
>81