Add Length_Delimited_String, As_Arp_Header, As_Ether_Addr, Address_To…

…_Access_String, WIP modified As_Arp function

eRINA_STM32F7/src/net/net-buffers.adb

@@ -16,9 +16,10 @@
 --  limitations under the License.
 -----------------------------------------------------------------------
 with Ada.Unchecked_Conversion;
-package body Net.Buffers is
+with System.Storage_Elements;  use System.Storage_Elements;
+with Net.Utils;
 
-   ETHER_POS : constant Uint16 := 0;
+package body Net.Buffers is
 
    type Offset_Table is array (Packet_Type) of Uint16;
 
@@ -29,8 +30,65 @@ package body Net.Buffers is
    function As_Ethernet is new Ada.Unchecked_Conversion
      (Source => System.Address, Target => Net.Headers.Ether_Header_Access);
 
-   function As_Arp is new Ada.Unchecked_Conversion
-     (Source => System.Address, Target => Net.Headers.Arp_Packet_Access);
+   --  An unchecked conversion no longer works here since we have length-delimited strings
+   --  i.e. we have no idea the length of the source and dest IPCP strings at compile time
+
+   --  function As_Arp is new Ada.Unchecked_Conversion
+   --    (Source => System.Address, Target => Net.Headers.Arp_Packet_Access);
+
+   function As_Arp_Header is new Ada.Unchecked_Conversion
+      (Source => System.Address, Target => Net.Headers.Arp_Header_Access);
+
+   type Ether_Addr_Access is access all Ether_Addr;
+
+   function As_Ether_Addr is new Ada.Unchecked_Conversion
+      (Source => System.Address, Target => Ether_Addr_Access);
+
+   function Address_To_Access_String (Address : System.Address; Length : Positive) return Net.Headers.Length_Delimited_String is
+      subtype Byte is System.Storage_Elements.Storage_Element;
+      type Byte_Array is array (Positive range <>) of Byte;
+
+      Temp : Byte_Array(1 .. Length);
+      for Temp'Address use Address;
+
+      Allocated_String : Net.Headers.Length_Delimited_String := new String'(1 .. Length => ' ');
+   begin
+      for I in 1 .. Length loop
+         Allocated_String(I) := Character'Val(Temp(I));
+      end loop;
+
+      return Allocated_String;
+   end Address_To_Access_String;
+
+   function As_Arp (Source : System.Address) return Net.Headers.Arp_Packet_Access is
+      --  Arp packet to be returned
+      Arp : constant Net.Headers.Arp_Packet_Access := new Net.Headers.Arp_Packet;
+      --  Ethernet header (this can be unchecked converted)
+      Ether : constant Net.Headers.Ether_Header_Access := As_Ethernet (Source);
+      --  Address starting where ARP packet begins (this can also be unchecked converted)
+      Ea_Hdr : constant Net.Headers.Arp_Header_Access := As_ARP_Header (Source + Storage_Offset(Offsets(ETHER_PACKET)));
+      --  Source MAC addr
+      Arp_Sha : constant Ether_Addr_Access := As_Ether_Addr (Source + Storage_Offset(Offsets(ARP_PACKET)));
+   begin
+      Arp.Ethernet := Ether.all;
+
+      --  I don't know why but the below doesn't work for me
+      --  Arp.Arp.Ea_Hdr := Ea_Hdr.all;
+
+      Arp.Arp.Ea_Hdr.Ar_Hdr := Ea_Hdr.Ar_Hdr;
+      Arp.Arp.Ea_Hdr.Ar_Pro := Ea_Hdr.Ar_Pro;
+      Arp.Arp.Ea_Hdr.Ar_Hln := Ea_Hdr.Ar_Hln;
+      Arp.Arp.Ea_Hdr.Ar_Pln := Ea_Hdr.Ar_Pln;
+      Arp.Arp.Ea_Hdr.Ar_Op := Ea_Hdr.Ar_Op;
+
+      Arp.Arp.Arp_Sha := Arp_Sha.all;
+      Arp.Arp.Arp_Spa := Address_To_Access_String (Source + Storage_Offset(Offsets(ARP_PACKET)), Positive(Arp.Arp.Ea_Hdr.Ar_Pro));
+
+      --Arp_Tha : Ether_Addr;
+      --Arp_Tpa : Length_Delimited_String;
+
+      return Arp;
+   end As_Arp;
 
    function As_EFCP is new Ada.Unchecked_Conversion
      (Source => System.Address, Target => Net.Headers.EFCP_Packet_Access);
@@ -316,15 +374,15 @@ package body Net.Buffers is
    --  Get access to the ARP packet.
    --  ------------------------------
    function Arp (Buf : in Buffer_Type) return Net.Headers.Arp_Packet_Access is
+      Result : Net.Headers.Arp_Packet_Access;
    begin
       return As_Arp (Buf.Packet.Data (Buf.Packet.Data'First)'Address);
    end Arp;
 
    --  ------------------------------
    --  Get access to the EFCP packet.
    --  ------------------------------
-   function EFCP (Buf : in Buffer_Type) return Net.Headers.EFCP_Packet_Access
-   is
+   function EFCP (Buf : in Buffer_Type) return Net.Headers.EFCP_Packet_Access is
    begin
       return As_EFCP (Buf.Packet.Data (Buf.Packet.Data'First)'Address);
    end EFCP;

eRINA_STM32F7/src/net/net-headers.ads

@@ -43,12 +43,15 @@ package Net.Headers is
       Ar_Op  : Uint16;
    end record;
 
+   type Arp_Header_Access is access Arp_Header;
+   type Length_Delimited_String is access String;
+
    type Ether_Arp is record
       Ea_Hdr  : Arp_Header;
-      Arp_Sha : Ether_Addr;
-      Arp_Spa : String (1 .. 6);
-      Arp_Tha : Ether_Addr;
-      Arp_Tpa : String (1 .. 6);
+      Arp_Sha : Ether_Addr := (others => 0);
+      Arp_Spa : Length_Delimited_String;
+      Arp_Tha : Ether_Addr := (others => 0);
+      Arp_Tpa : Length_Delimited_String;
    end record;
    type Ether_Arp_Access is access all Ether_Arp;