[Ada] GNAT.Sockets: add IPv6 support

2018-12-11  Dmitriy Anisimkov  <anisimko@adacore.com>

gcc/ada/

	* libgnat/g-socket.ads (Family_Type): Add new enumerated value
	Family_Unspec to be able to use it in Get_Address_Info parameter
	and find IPv4 together with IPv6 addresses.
	(Inet_Addr_Bytes_Length): Zero length for Family_Unspec.  New
	IPv6 predefined constant addresses.
	(IPv4_To_IPv6_Prefix): IPv4 mapped to IPv6 address prefix.
	(Is_IPv4_Address): Rename from Is_IP_Address and published.
	(Is_IPv6_Address): New routine.
	(Image of Inet_Addr_Type): Fix description about IPv6 address
	text representation.
	(Level_Type): New propocol level IP_Protocol_For_IPv6_Level.
	(Add_Membership_V4): New socket option equal to Add_Membership.
	(Drop_Membership_V4): New socket option equal to
	Drop_Membership.
	(Multicast_If_V4): New socket option equal to Multicast_If.
	(Multicast_Loop_V4, Add_Membership_V6, Drop_Membership_V6,
	Multicast_If_V6, Multicast_Loop_V6, Multicast_Hops, IPv6_Only):
	New socket option for IPv6.
	(Address_Info): New record to keep address info.
	(Address_Info_Array): Array to keep address info records.
	(Get_Address_Info): Routine to get address info records by host
	and service names.
	(Host_Service): Record to keep host and service names.
	(Get_Name_Info): New routine to get host and service names by
	address.
	(Create_Socket): Add Level parameter, IP_Protocol_For_IP_Level
	default.
	(Name_Array, Inet_Addr_Array): Change array index to Positive.
	* libgnat/g-socket.adb (IPV6_Mreq): New record definition for
	IPv6.
	(Hex_To_Char): Remove.
	(Short_To_Network, Network_To_Short): Move to package
	GNAT.Sockets.Thin_Common.
	(Is_IP_Address): Remove.
	(To_In_Addr, To_Inet_Addr): Move to package
	GNAT.Sockets.Thin_Common.
	(Get_Socket_Option): Get value of Multicast_Loop option as
	integer boolean, process IPv6 options. Don't try to get
	Add_Membership_V4, Add_Membership_V6, Drop_Membership_V4, and
	Drop_Membership_V6 as not supported by the socket API.
	(Set_Socket_Option): Set value of Multicast_Loop option as
	integer boolean, process IPv6 options.
	* gsocket.h
	(IPV6_ADD_MEMBERSHIP): Define from IPV6_JOIN_GROUP if necessary
	for VxWorks.
	(IPV6_DROP_MEMBERSHIP): Define from IPV6_LEAVE_GROUP if
	necessary for VxWorks
	(HAVE_INET_NTOP): New definition.
	(HAVE_INET_PTON): Includes VxWorks now.
	* socket.c (__gnat_getaddrinfo, __gnat_getnameinfo,
	__gnat_freeaddrinfo, __gnat_gai_strerror, __gnat_inet_ntop): New
	routines.
	* libgnat/g-sothco.ads, libgnat/g-sothco.adb
	(socklen_t, In6_Addr, To_In6_Addr): New.
	(To_In_Addr, To_Inet_Addr): Move from package body GNAT.Sockets.
	(To_Inet_Addr): New overload with In6_Addr type parmeter.
	(In_Addr_Access_Array): Remove.
	(Sockaddr): Unchecked_Union instead of Sockaddr_In and old
	defined generic Sockaddr.
	(Set_Address): Use it to set family, port and address into
	Sockaddr.
	(Get_Address): New routine to get Socket_Addr_Type from
	Sockaddr.
	(Addrinfo): Structure to use with getaddrinfo.
	(C_Getaddrinfo, C_Freeaddrinfo, C_Getnameinfo, C_GAI_Strerror,
	Inet_Ntop): New routine import.
	(Short_To_Network, Network_To_Short): Move from package body
	GNAT.Sockets.
	* libgnat/g-stsifd__sockets.adb: Use Sockaddr instead of
	Sockaddr_In.
	* s-oscons-tmplt.c (AF_UNSPEC, EAI_SYSTEM, SOCK_RAW,
	IPPROTO_IPV6, IP_RECVERR, SIZEOF_socklen_t, IF_NAMESIZE): New
	constants.
	(AI_xxxx_OFFSET): Constants to consider platform differences in
	field positions and sizes for addrinfo structure.
	(AI_xxxxx): Flags for getaddrinfo.
	(NI_xxxxx): Flags for getnameinfo.
	(IPV6_xxxxx): Socket options for IPv6.
	(Inet_Ntop_Linkname): New routine.

From-SVN: r267016

gcc/ada/ChangeLog

+2018-12-11  Dmitriy Anisimkov  <anisimko@adacore.com>
+
+	* libgnat/g-socket.ads (Family_Type): Add new enumerated value
+	Family_Unspec to be able to use it in Get_Address_Info parameter
+	and find IPv4 together with IPv6 addresses.
+	(Inet_Addr_Bytes_Length): Zero length for Family_Unspec.  New
+	IPv6 predefined constant addresses.
+	(IPv4_To_IPv6_Prefix): IPv4 mapped to IPv6 address prefix.
+	(Is_IPv4_Address): Rename from Is_IP_Address and published.
+	(Is_IPv6_Address): New routine.
+	(Image of Inet_Addr_Type): Fix description about IPv6 address
+	text representation.
+	(Level_Type): New propocol level IP_Protocol_For_IPv6_Level.
+	(Add_Membership_V4): New socket option equal to Add_Membership.
+	(Drop_Membership_V4): New socket option equal to
+	Drop_Membership.
+	(Multicast_If_V4): New socket option equal to Multicast_If.
+	(Multicast_Loop_V4, Add_Membership_V6, Drop_Membership_V6,
+	Multicast_If_V6, Multicast_Loop_V6, Multicast_Hops, IPv6_Only):
+	New socket option for IPv6.
+	(Address_Info): New record to keep address info.
+	(Address_Info_Array): Array to keep address info records.
+	(Get_Address_Info): Routine to get address info records by host
+	and service names.
+	(Host_Service): Record to keep host and service names.
+	(Get_Name_Info): New routine to get host and service names by
+	address.
+	(Create_Socket): Add Level parameter, IP_Protocol_For_IP_Level
+	default.
+	(Name_Array, Inet_Addr_Array): Change array index to Positive.
+	* libgnat/g-socket.adb (IPV6_Mreq): New record definition for
+	IPv6.
+	(Hex_To_Char): Remove.
+	(Short_To_Network, Network_To_Short): Move to package
+	GNAT.Sockets.Thin_Common.
+	(Is_IP_Address): Remove.
+	(To_In_Addr, To_Inet_Addr): Move to package
+	GNAT.Sockets.Thin_Common.
+	(Get_Socket_Option): Get value of Multicast_Loop option as
+	integer boolean, process IPv6 options. Don't try to get
+	Add_Membership_V4, Add_Membership_V6, Drop_Membership_V4, and
+	Drop_Membership_V6 as not supported by the socket API.
+	(Set_Socket_Option): Set value of Multicast_Loop option as
+	integer boolean, process IPv6 options.
+	* gsocket.h
+	(IPV6_ADD_MEMBERSHIP): Define from IPV6_JOIN_GROUP if necessary
+	for VxWorks.
+	(IPV6_DROP_MEMBERSHIP): Define from IPV6_LEAVE_GROUP if
+	necessary for VxWorks
+	(HAVE_INET_NTOP): New definition.
+	(HAVE_INET_PTON): Includes VxWorks now.
+	* socket.c (__gnat_getaddrinfo, __gnat_getnameinfo,
+	__gnat_freeaddrinfo, __gnat_gai_strerror, __gnat_inet_ntop): New
+	routines.
+	* libgnat/g-sothco.ads, libgnat/g-sothco.adb
+	(socklen_t, In6_Addr, To_In6_Addr): New.
+	(To_In_Addr, To_Inet_Addr): Move from package body GNAT.Sockets.
+	(To_Inet_Addr): New overload with In6_Addr type parmeter.
+	(In_Addr_Access_Array): Remove.
+	(Sockaddr): Unchecked_Union instead of Sockaddr_In and old
+	defined generic Sockaddr.
+	(Set_Address): Use it to set family, port and address into
+	Sockaddr.
+	(Get_Address): New routine to get Socket_Addr_Type from
+	Sockaddr.
+	(Addrinfo): Structure to use with getaddrinfo.
+	(C_Getaddrinfo, C_Freeaddrinfo, C_Getnameinfo, C_GAI_Strerror,
+	Inet_Ntop): New routine import.
+	(Short_To_Network, Network_To_Short): Move from package body
+	GNAT.Sockets.
+	* libgnat/g-stsifd__sockets.adb: Use Sockaddr instead of
+	Sockaddr_In.
+	* s-oscons-tmplt.c (AF_UNSPEC, EAI_SYSTEM, SOCK_RAW,
+	IPPROTO_IPV6, IP_RECVERR, SIZEOF_socklen_t, IF_NAMESIZE): New
+	constants.
+	(AI_xxxx_OFFSET): Constants to consider platform differences in
+	field positions and sizes for addrinfo structure.
+	(AI_xxxxx): Flags for getaddrinfo.
+	(NI_xxxxx): Flags for getnameinfo.
+	(IPV6_xxxxx): Socket options for IPv6.
+	(Inet_Ntop_Linkname): New routine.
+
 2018-12-11  Yannick Moy  <moy@adacore.com>
 
 	* sem_ch6.adb (Analyze_Subprogram_Body_Helper): Deactivate

gcc/ada/gsocket.h

@@ -63,10 +63,19 @@
 #include <vxWorks.h>
 #include <ioLib.h>
 #include <hostLib.h>
+
 #define SHUT_RD		0
 #define SHUT_WR		1
 #define SHUT_RDWR	2
 
+#ifndef IPV6_ADD_MEMBERSHIP
+#define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
+#endif
+
+#ifndef IPV6_DROP_MEMBERSHIP
+#define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
+#endif
+
 #elif defined (WINNT)
 #define FD_SETSIZE 1024
 
@@ -250,8 +259,9 @@
 # define Has_Sockaddr_Len 0
 #endif
 
-#if !(defined (__vxworks) || defined (_WIN32) || defined (__hpux__) || defined (VMS))
+#if !(defined (_WIN32) || defined (__hpux__) || defined (VMS))
 # define HAVE_INET_PTON
+# define HAVE_INET_NTOP
 #endif
 
 #endif /* defined(VTHREADS) */

gcc/ada/libgnat/g-socket.adb

@@ -31,6 +31,7 @@
 
 with Ada.Streams;              use Ada.Streams;
 with Ada.Exceptions;           use Ada.Exceptions;
+with Ada.Containers.Generic_Array_Sort;
 with Ada.Finalization;
 with Ada.Unchecked_Conversion;
 
@@ -50,6 +51,12 @@ package body GNAT.Sockets is
 
    package C renames Interfaces.C;
 
+   type IPV6_Mreq is record
+      ipv6mr_multiaddr : In6_Addr;
+      ipv6mr_interface : C.unsigned;
+   end record with Convention => C;
+   --  Record to Add/Drop_Membership for multicast in IPv6
+
    ENOERROR : constant := 0;
 
    Netdb_Buffer_Size : constant := SOSC.Need_Netdb_Buffer * 1024;
@@ -64,6 +71,7 @@ package body GNAT.Sockets is
    Levels : constant array (Level_Type) of C.int :=
               (Socket_Level               => SOSC.SOL_SOCKET,
                IP_Protocol_For_IP_Level   => SOSC.IPPROTO_IP,
+               IP_Protocol_For_IPv6_Level => SOSC.IPPROTO_IPV6,
                IP_Protocol_For_UDP_Level  => SOSC.IPPROTO_UDP,
                IP_Protocol_For_TCP_Level  => SOSC.IPPROTO_TCP);
 
@@ -89,12 +97,18 @@ package body GNAT.Sockets is
                 Linger              => SOSC.SO_LINGER,
                 Error               => SOSC.SO_ERROR,
                 No_Delay            => SOSC.TCP_NODELAY,
-                Add_Membership      => SOSC.IP_ADD_MEMBERSHIP,
-                Drop_Membership     => SOSC.IP_DROP_MEMBERSHIP,
-                Multicast_If        => SOSC.IP_MULTICAST_IF,
-                Multicast_TTL       => SOSC.IP_MULTICAST_TTL,
-                Multicast_Loop      => SOSC.IP_MULTICAST_LOOP,
+                Add_Membership_V4   => SOSC.IP_ADD_MEMBERSHIP,
+                Drop_Membership_V4  => SOSC.IP_DROP_MEMBERSHIP,
+                Multicast_If_V4     => SOSC.IP_MULTICAST_IF,
+                Multicast_Loop_V4   => SOSC.IP_MULTICAST_LOOP,
                 Receive_Packet_Info => SOSC.IP_PKTINFO,
+                Multicast_TTL       => SOSC.IP_MULTICAST_TTL,
+                Add_Membership_V6   => SOSC.IPV6_ADD_MEMBERSHIP,
+                Drop_Membership_V6  => SOSC.IPV6_DROP_MEMBERSHIP,
+                Multicast_If_V6     => SOSC.IPV6_MULTICAST_IF,
+                Multicast_Loop_V6   => SOSC.IPV6_MULTICAST_LOOP,
+                Multicast_Hops      => SOSC.IPV6_MULTICAST_HOPS,
+                IPv6_Only           => SOSC.IPV6_V6ONLY,
                 Send_Timeout        => SOSC.SO_SNDTIMEO,
                 Receive_Timeout     => SOSC.SO_RCVTIMEO,
                 Busy_Polling        => SOSC.SO_BUSY_POLL);
@@ -110,8 +124,16 @@ package body GNAT.Sockets is
    Socket_Error_Id : constant Exception_Id := Socket_Error'Identity;
    Host_Error_Id   : constant Exception_Id := Host_Error'Identity;
 
-   Hex_To_Char : constant String (1 .. 16) := "0123456789ABCDEF";
-   --  Use to print in hexadecimal format
+   type In_Addr_Union (Family : Family_Type) is record
+      case Family is
+         when Family_Inet =>
+            In4 : In_Addr;
+         when Family_Inet6 =>
+            In6 : In6_Addr;
+         when Family_Unspec =>
+            null;
+      end case;
+   end record with Unchecked_Union;
 
    -----------------------
    -- Local subprograms --
@@ -133,24 +155,6 @@ package body GNAT.Sockets is
    function Set_Forced_Flags (F : C.int) return C.int;
    --  Return F with the bits from SOSC.MSG_Forced_Flags forced set
 
-   function Short_To_Network
-     (S : C.unsigned_short) return C.unsigned_short;
-   pragma Inline (Short_To_Network);
-   --  Convert a port number into a network port number
-
-   function Network_To_Short
-     (S : C.unsigned_short) return C.unsigned_short
-   renames Short_To_Network;
-   --  Symmetric operation
-
-   function Image
-     (Val : Inet_Addr_Bytes;
-      Hex : Boolean := False) return String;
-   --  Output an array of inet address components in hex or decimal mode
-
-   function Is_IP_Address (Name : String) return Boolean;
-   --  Return true when Name is an IPv4 address in dotted quad notation
-
    procedure Netdb_Lock;
    pragma Inline (Netdb_Lock);
    procedure Netdb_Unlock;
@@ -158,12 +162,6 @@ package body GNAT.Sockets is
    --  Lock/unlock operation used to protect netdb access for platforms that
    --  require such protection.
 
-   function To_In_Addr (Addr : Inet_Addr_Type) return In_Addr;
-   procedure To_Inet_Addr
-     (Addr   : In_Addr;
-      Result : out Inet_Addr_Type);
-   --  Conversion functions
-
    function To_Host_Entry (E : Hostent_Access) return Host_Entry_Type;
    --  Conversion function
 
@@ -180,6 +178,12 @@ package body GNAT.Sockets is
    --  Reconstruct a Duration value from a Timeval record (seconds and
    --  microseconds).
 
+   function Dedot (Value : String) return String
+   is (if Value /= "" and then Value (Value'Last) = '.'
+       then Value (Value'First .. Value'Last - 1)
+       else Value);
+   --  Removes dot at the end of error message
+
    procedure Raise_Socket_Error (Error : Integer);
    --  Raise Socket_Error with an exception message describing the error code
    --  from errno.
@@ -189,6 +193,13 @@ package body GNAT.Sockets is
    --  hstrerror seems to be obsolete) from h_errno. Name is the name
    --  or address that was being looked up.
 
+   procedure Raise_GAI_Error (RC : C.int; Name : String);
+   --  Raise Host_Error with exception message in case of errors in
+   --  getaddrinfo and getnameinfo.
+
+   function Is_Windows return Boolean with Inline;
+   --  Returns True on Windows platform
+
    procedure Narrow (Item : in out Socket_Set_Type);
    --  Update Last as it may be greater than the real last socket
 
@@ -328,7 +339,7 @@ package body GNAT.Sockets is
       Address : out Sock_Addr_Type)
    is
       Res : C.int;
-      Sin : aliased Sockaddr_In;
+      Sin : aliased Sockaddr;
       Len : aliased C.int := Sin'Size / 8;
 
    begin
@@ -339,9 +350,7 @@ package body GNAT.Sockets is
       end if;
 
       Socket := Socket_Type (Res);
-
-      To_Inet_Addr (Sin.Sin_Addr, Address.Addr);
-      Address.Port := Port_Type (Network_To_Short (Sin.Sin_Port));
+      Address := Get_Address (Sin);
    end Accept_Socket;
 
    -------------------
@@ -451,20 +460,11 @@ package body GNAT.Sockets is
       Address : Sock_Addr_Type)
    is
       Res : C.int;
-      Sin : aliased Sockaddr_In;
+      Sin : aliased Sockaddr;
       Len : constant C.int := Sin'Size / 8;
-      --  This assumes that Address.Family = Family_Inet???
 
    begin
-      if Address.Family = Family_Inet6 then
-         raise Socket_Error with "IPv6 not supported";
-      end if;
-
-      Set_Family  (Sin.Sin_Family, Address.Family);
-      Set_Address (Sin'Unchecked_Access, To_In_Addr (Address.Addr));
-      Set_Port
-        (Sin'Unchecked_Access,
-         Short_To_Network (C.unsigned_short (Address.Port)));
+      Set_Address (Sin'Unchecked_Access, Address);
 
       Res := C_Bind (C.int (Socket), Sin'Address, Len);
 
@@ -478,14 +478,12 @@ package body GNAT.Sockets is
    ----------------------
 
    procedure Check_For_Fd_Set (Fd : Socket_Type) is
-      use SOSC;
-
    begin
       --  On Windows, fd_set is a FD_SETSIZE array of socket ids:
       --  no check required. Warnings suppressed because condition
       --  is known at compile time.
 
-      if Target_OS = Windows then
+      if Is_Windows then
 
          return;
 
@@ -667,19 +665,11 @@ package body GNAT.Sockets is
      (Socket : Socket_Type;
       Server : Sock_Addr_Type) return C.int
    is
-      Sin : aliased Sockaddr_In;
+      Sin : aliased Sockaddr;
       Len : constant C.int := Sin'Size / 8;
 
    begin
-      if Server.Family = Family_Inet6 then
-         raise Socket_Error with "IPv6 not supported";
-      end if;
-
-      Set_Family  (Sin.Sin_Family, Server.Family);
-      Set_Address (Sin'Unchecked_Access, To_In_Addr (Server.Addr));
-      Set_Port
-        (Sin'Unchecked_Access,
-         Short_To_Network (C.unsigned_short (Server.Port)));
+      Set_Address (Sin'Unchecked_Access, Server);
 
       return C_Connect (C.int (Socket), Sin'Address, Len);
    end Connect_Socket;
@@ -861,12 +851,13 @@ package body GNAT.Sockets is
    procedure Create_Socket
      (Socket : out Socket_Type;
       Family : Family_Type := Family_Inet;
-      Mode   : Mode_Type   := Socket_Stream)
+      Mode   : Mode_Type   := Socket_Stream;
+      Level  : Level_Type  := IP_Protocol_For_IP_Level)
    is
       Res : C.int;
 
    begin
-      Res := C_Socket (Families (Family), Modes (Mode), 0);
+      Res := C_Socket (Families (Family), Modes (Mode), Levels (Level));
 
       if Res = Failure then
          Raise_Socket_Error (Socket_Errno);
@@ -959,6 +950,228 @@ package body GNAT.Sockets is
       end if;
    end Get_Address;
 
+   ---------------------
+   -- Raise_GAI_Error --
+   ---------------------
+
+   procedure Raise_GAI_Error (RC : C.int; Name : String) is
+   begin
+      if RC = SOSC.EAI_SYSTEM then
+         declare
+            Errcode : constant Integer := Socket_Errno;
+         begin
+            raise Host_Error with Err_Code_Image (Errcode)
+              & Dedot (Socket_Error_Message (Errcode)) & ": " & Name;
+         end;
+      else
+         raise Host_Error with Err_Code_Image (Integer (RC))
+           & Dedot (CS.Value (C_GAI_Strerror (RC))) & ": " & Name;
+      end if;
+   end Raise_GAI_Error;
+
+   ----------------------
+   -- Get_Address_Info --
+   ----------------------
+
+   function Get_Address_Info
+     (Host         : String;
+      Service      : String;
+      Family       : Family_Type := Family_Unspec;
+      Mode         : Mode_Type   := Socket_Stream;
+      Level        : Level_Type  := IP_Protocol_For_IP_Level;
+      Numeric_Host : Boolean     := False;
+      Passive      : Boolean     := False;
+      Unknown      : access procedure
+        (Family, Mode, Level, Length : Integer) := null)
+      return Address_Info_Array
+   is
+      A : aliased Addrinfo_Access;
+      N : aliased C.char_array := C.To_C (Host);
+      S : aliased C.char_array := C.To_C (if Service = "" then "0"
+                                          else Service);
+      Hints : aliased constant Addrinfo :=
+        (ai_family   => Families (Family),
+         ai_socktype => Modes (Mode),
+         ai_protocol => Levels (Level),
+         ai_flags    => (if Numeric_Host then SOSC.AI_NUMERICHOST else 0) +
+                        (if Passive then SOSC.AI_PASSIVE else 0),
+         ai_addrlen  => 0,
+         others      => <>);
+
+      R     : C.int;
+      Iter  : Addrinfo_Access;
+      Found : Boolean;
+
+      function To_Array return Address_Info_Array;
+      --  Convert taken from OS addrinfo list A into Address_Info_Array
+
+      --------------
+      -- To_Array --
+      --------------
+
+      function To_Array return Address_Info_Array is
+         Result : Address_Info_Array (1 .. 8);
+
+         procedure Unsupported;
+         --  Calls Unknown callback if defiend
+
+         -----------------
+         -- Unsupported --
+         -----------------
+
+         procedure Unsupported is
+         begin
+            if Unknown /= null then
+               Unknown
+                 (Integer (Iter.ai_family),
+                  Integer (Iter.ai_socktype),
+                  Integer (Iter.ai_protocol),
+                  Integer (Iter.ai_addrlen));
+            end if;
+         end Unsupported;
+
+      --  Start of processing for To_Array
+
+      begin
+         for J in Result'Range loop
+            Look_For_Supported : loop
+               if Iter = null then
+                  return Result (1 .. J - 1);
+               end if;
+
+               Result (J).Addr := Get_Address (Iter.ai_addr.all);
+
+               if Result (J).Addr.Family = Family_Unspec then
+                  Unsupported;
+               else
+                  for M in Modes'Range loop
+                     Found := False;
+                     if Modes (M) = Iter.ai_socktype then
+                        Result (J).Mode := M;
+                        Found := True;
+                        exit;
+                     end if;
+                  end loop;
+
+                  if Found then
+                     for L in Levels'Range loop
+                        if Levels (L) = Iter.ai_protocol then
+                           Result (J).Level := L;
+                           exit;
+                        end if;
+                     end loop;
+
+                     exit Look_For_Supported;
+                  else
+                     Unsupported;
+                  end if;
+               end if;
+
+               Iter := Iter.ai_next;
+
+               if Iter = null then
+                  return Result (1 .. J - 1);
+               end if;
+            end loop Look_For_Supported;
+
+            Iter := Iter.ai_next;
+         end loop;
+
+         return Result & To_Array;
+      end To_Array;
+
+   --  Start of processing for Get_Address_Info
+
+   begin
+      R := C_Getaddrinfo
+        (Node    => (if Host = "" then null else N'Unchecked_Access),
+         Service => S'Unchecked_Access,
+         Hints   => Hints'Unchecked_Access,
+         Res     => A'Access);
+
+      if R /= 0 then
+         Raise_GAI_Error
+           (R, Host & (if Service = "" then "" else ':' & Service));
+      end if;
+
+      Iter := A;
+
+      return Result : constant Address_Info_Array := To_Array do
+         C_Freeaddrinfo (A);
+      end return;
+   end Get_Address_Info;
+
+   ----------
+   -- Sort --
+   ----------
+
+   procedure Sort
+     (Addr_Info : in out Address_Info_Array;
+      Compare   : access function (Left, Right : Address_Info) return Boolean)
+   is
+      function Comp (Left, Right : Address_Info) return Boolean is
+         (Compare (Left, Right));
+      procedure Sorter is new Ada.Containers.Generic_Array_Sort
+        (Positive, Address_Info, Address_Info_Array, Comp);
+   begin
+      Sorter (Addr_Info);
+   end Sort;
+
+   ------------------------
+   -- IPv6_TCP_Preferred --
+   ------------------------
+
+   function IPv6_TCP_Preferred (Left, Right : Address_Info) return Boolean is
+   begin
+      pragma Assert (Family_Inet < Family_Inet6);
+      --  To be sure that Family_Type enumeration has appropriate elements
+      --  order
+
+      if Left.Addr.Family /= Right.Addr.Family then
+         return Left.Addr.Family > Right.Addr.Family;
+      end if;
+
+      pragma Assert (Socket_Stream < Socket_Datagram);
+      --  To be sure that Mode_Type enumeration has appropriate elements order
+
+      return Left.Mode < Right.Mode;
+   end IPv6_TCP_Preferred;
+
+   -------------------
+   -- Get_Name_Info --
+   -------------------
+
+   function Get_Name_Info
+     (Addr         : Sock_Addr_Type;
+      Numeric_Host : Boolean := False;
+      Numeric_Serv : Boolean := False) return Host_Service
+   is
+      SA : aliased Sockaddr;
+      H  : aliased C.char_array := (1 .. SOSC.NI_MAXHOST => C.nul);
+      S  : aliased C.char_array := (1 .. SOSC.NI_MAXSERV => C.nul);
+      RC : C.int;
+   begin
+      Set_Address (SA'Unchecked_Access, Addr);
+
+      RC := C_Getnameinfo
+        (SA'Unchecked_Access, socklen_t (Lengths (Addr.Family)),
+         H'Unchecked_Access, H'Length,
+         S'Unchecked_Access, S'Length,
+         (if Numeric_Host then SOSC.NI_NUMERICHOST else 0) +
+             (if Numeric_Serv then SOSC.NI_NUMERICSERV else 0));
+
+      if RC /= 0 then
+         Raise_GAI_Error (RC, Image (Addr));
+      end if;
+
+      declare
+         HR : constant String := C.To_Ada (H);
+         SR : constant String := C.To_Ada (S);
+      begin
+         return (HR'Length, SR'Length, HR, SR);
+      end;
+   end Get_Name_Info;
+
    -------------------------
    -- Get_Host_By_Address --
    -------------------------
@@ -969,16 +1182,32 @@ package body GNAT.Sockets is
    is
       pragma Unreferenced (Family);
 
-      HA     : aliased In_Addr := To_In_Addr (Address);
+      HA     : aliased In_Addr_Union (Address.Family);
       Buflen : constant C.int := Netdb_Buffer_Size;
       Buf    : aliased C.char_array (1 .. Netdb_Buffer_Size);
       Res    : aliased Hostent;
       Err    : aliased C.int;
 
    begin
+      case Address.Family is
+         when Family_Inet =>
+            HA.In4 := To_In_Addr (Address);
+         when Family_Inet6 =>
+            HA.In6 := To_In6_Addr (Address);
+         when Family_Unspec =>
+            return (0, 0, (1, " "), (1 .. 0 => (1, " ")),
+                    (1 .. 0 => No_Inet_Addr));
+      end case;
+
       Netdb_Lock;
 
-      if C_Gethostbyaddr (HA'Address, HA'Size / 8, SOSC.AF_INET,
+      if C_Gethostbyaddr
+        (HA'Address,
+         (case Address.Family is
+             when Family_Inet => HA.In4'Size,
+             when Family_Inet6 => HA.In6'Size,
+             when Family_Unspec => 0) / 8,
+         Families (Address.Family),
          Res'Access, Buf'Address, Buflen, Err'Access) /= 0
       then
          Netdb_Unlock;
@@ -1007,7 +1236,7 @@ package body GNAT.Sockets is
       --  If the given name actually is the string representation of
       --  an IP address, use Get_Host_By_Address instead.
 
-      if Is_IP_Address (Name) then
+      if Is_IPv4_Address (Name) or else Is_IPv6_Address (Name) then
          return Get_Host_By_Address (Inet_Addr (Name));
       end if;
 
@@ -1041,19 +1270,14 @@ package body GNAT.Sockets is
    -------------------
 
    function Get_Peer_Name (Socket : Socket_Type) return Sock_Addr_Type is
-      Sin : aliased Sockaddr_In;
+      Sin : aliased Sockaddr;
       Len : aliased C.int := Sin'Size / 8;
-      Res : Sock_Addr_Type (Family_Inet);
-
    begin
       if C_Getpeername (C.int (Socket), Sin'Address, Len'Access) = Failure then
          Raise_Socket_Error (Socket_Errno);
       end if;
 
-      To_Inet_Addr (Sin.Sin_Addr, Res.Addr);
-      Res.Port := Port_Type (Network_To_Short (Sin.Sin_Port));
-
-      return Res;
+      return Get_Address (Sin);
    end Get_Peer_Name;
 
    -------------------------
@@ -1127,20 +1351,17 @@ package body GNAT.Sockets is
    function Get_Socket_Name
      (Socket : Socket_Type) return Sock_Addr_Type
    is
-      Sin  : aliased Sockaddr_In;
+      Sin : aliased Sockaddr;
       Len : aliased C.int := Sin'Size / 8;
       Res : C.int;
-      Addr : Sock_Addr_Type := No_Sock_Addr;
-
    begin
       Res := C_Getsockname (C.int (Socket), Sin'Address, Len'Access);
 
-      if Res /= Failure then
-         To_Inet_Addr (Sin.Sin_Addr, Addr.Addr);
-         Addr.Port := Port_Type (Network_To_Short (Sin.Sin_Port));
+      if Res = Failure then
+         return No_Sock_Addr;
       end if;
 
-      return Addr;
+      return Get_Address (Sin);
    end Get_Socket_Name;
 
    -----------------------
@@ -1153,7 +1374,6 @@ package body GNAT.Sockets is
       Name    : Option_Name;
       Optname : Interfaces.C.int := -1) return Option_Type
    is
-      use SOSC;
       use type C.unsigned;
       use type C.unsigned_char;
 
@@ -1180,8 +1400,7 @@ package body GNAT.Sockets is
       end if;
 
       case Name is
-         when Multicast_Loop
-            | Multicast_TTL
+         when Multicast_TTL
             | Receive_Packet_Info
          =>
             Len := V1'Size / 8;
@@ -1192,11 +1411,16 @@ package body GNAT.Sockets is
             | Error
             | Generic_Option
             | Keep_Alive
-            | Multicast_If
+            | Multicast_If_V4
+            | Multicast_If_V6
+            | Multicast_Loop_V4
+            | Multicast_Loop_V6
+            | Multicast_Hops
             | No_Delay
             | Receive_Buffer
             | Reuse_Address
             | Send_Buffer
+            | IPv6_Only
          =>
             Len := V4'Size / 8;
             Add := V4'Address;
@@ -1208,18 +1432,23 @@ package body GNAT.Sockets is
             --  struct timeval, but on Windows it is a milliseconds count in
             --  a DWORD.
 
-            if Target_OS = Windows then
+            if Is_Windows then
                Len := U4'Size / 8;
                Add := U4'Address;
-
             else
                Len := VT'Size / 8;
                Add := VT'Address;
             end if;
 
-         when Add_Membership
-            | Drop_Membership
-            | Linger
+         when Add_Membership_V4
+            | Add_Membership_V6
+            | Drop_Membership_V4
+            | Drop_Membership_V6
+         =>
+            raise Socket_Error with
+              "Add/Drop membership valid only for Set_Socket_Option";
+
+         when Linger
          =>
             Len := V8'Size / 8;
             Add := V8'Address;
@@ -1245,6 +1474,9 @@ package body GNAT.Sockets is
             | Keep_Alive
             | No_Delay
             | Reuse_Address
+            | Multicast_Loop_V4
+            | Multicast_Loop_V6
+            | IPv6_Only
          =>
             Opt.Enabled := (V4 /= 0);
 
@@ -1263,27 +1495,35 @@ package body GNAT.Sockets is
          when Error =>
             Opt.Error := Resolve_Error (Integer (V4));
 
-         when Add_Membership
-            | Drop_Membership
+         when Add_Membership_V4
+            | Add_Membership_V6
+            | Drop_Membership_V4
+            | Drop_Membership_V6
          =>
-            To_Inet_Addr (To_In_Addr (V8 (V8'First)), Opt.Multicast_Address);
-            To_Inet_Addr (To_In_Addr (V8 (V8'Last)), Opt.Local_Interface);
+            --  No way to be here. Exception raised in the first case Name
+            --  expression.
+            null;
 
-         when Multicast_If =>
+         when Multicast_If_V4 =>
             To_Inet_Addr (To_In_Addr (V4), Opt.Outgoing_If);
 
+         when Multicast_If_V6 =>
+            Opt.Outgoing_If_Index := Natural (V4);
+
          when Multicast_TTL =>
             Opt.Time_To_Live := Integer (V1);
 
-         when Multicast_Loop
-            | Receive_Packet_Info
+         when Multicast_Hops =>
+            Opt.Hop_Limit := Integer (V4);
+
+         when Receive_Packet_Info
          =>
             Opt.Enabled := (V1 /= 0);
 
          when Receive_Timeout
             | Send_Timeout
          =>
-            if Target_OS = Windows then
+            if Is_Windows then
 
                --  Timeout is in milliseconds, actual value is 500 ms +
                --  returned value (unless it is 0).
@@ -1324,78 +1564,34 @@ package body GNAT.Sockets is
    -- Image --
    -----------
 
-   function Image
-     (Val : Inet_Addr_Bytes;
-      Hex : Boolean := False) return String
-   is
-      --  The largest Inet_Addr_Comp_Type image occurs with IPv4. It
-      --  has at most a length of 3 plus one '.' character.
-
-      Buffer    : String (1 .. 4 * Val'Length);
-      Length    : Natural := 1;
-      Separator : Character;
-
-      procedure Img10 (V : Inet_Addr_Comp_Type);
-      --  Append to Buffer image of V in decimal format
-
-      procedure Img16 (V : Inet_Addr_Comp_Type);
-      --  Append to Buffer image of V in hexadecimal format
-
-      -----------
-      -- Img10 --
-      -----------
-
-      procedure Img10 (V : Inet_Addr_Comp_Type) is
-         Img : constant String := V'Img;
-         Len : constant Natural := Img'Length - 1;
-      begin
-         Buffer (Length .. Length + Len - 1) := Img (2 .. Img'Last);
-         Length := Length + Len;
-      end Img10;
-
-      -----------
-      -- Img16 --
-      -----------
-
-      procedure Img16 (V : Inet_Addr_Comp_Type) is
-      begin
-         Buffer (Length)     := Hex_To_Char (Natural (V / 16) + 1);
-         Buffer (Length + 1) := Hex_To_Char (Natural (V mod 16) + 1);
-         Length := Length + 2;
-      end Img16;
-
-   --  Start of processing for Image
-
-   begin
-      Separator := (if Hex then ':' else '.');
-
-      for J in Val'Range loop
-         if Hex then
-            Img16 (Val (J));
-         else
-            Img10 (Val (J));
-         end if;
+   function Image (Value : Inet_Addr_Type) return String is
+      use type CS.char_array_access;
+      Size : constant socklen_t :=
+        (case Value.Family is
+            when Family_Inet   => 4 * Value.Sin_V4'Length,
+            when Family_Inet6  => 6 * 5 + 4 * 4,
+            --  1234:1234:1234:1234:1234:1234:123.123.123.123
+            when Family_Unspec => 0);
+      Dst : aliased C.char_array := (1 .. C.size_t (Size) => C.nul);
+      Ia  : aliased In_Addr_Union (Value.Family);
+   begin
+      case Value.Family is
+         when Family_Inet6 =>
+            Ia.In6 := To_In6_Addr (Value);
+         when Family_Inet =>
+            Ia.In4 := To_In_Addr (Value);
+         when Family_Unspec =>
+            return "";
+      end case;
 
-         if J /= Val'Last then
-            Buffer (Length) := Separator;
-            Length := Length + 1;
+      if Inet_Ntop
+        (Families (Value.Family), Ia'Address,
+         Dst'Unchecked_Access, Size) = null
+      then
+         Raise_Socket_Error (Socket_Errno);
       end if;
-      end loop;
 
-      return Buffer (1 .. Length - 1);
-   end Image;
-
-   -----------
-   -- Image --
-   -----------
-
-   function Image (Value : Inet_Addr_Type) return String is
-   begin
-      if Value.Family = Family_Inet then
-         return Image (Inet_Addr_Bytes (Value.Sin_V4), Hex => False);
-      else
-         return Image (Inet_Addr_Bytes (Value.Sin_V6), Hex => True);
-      end if;
+      return C.To_Ada (Dst);
    end Image;
 
    -----------
@@ -1404,8 +1600,10 @@ package body GNAT.Sockets is
 
    function Image (Value : Sock_Addr_Type) return String is
       Port : constant String := Value.Port'Img;
+      function Ipv6_Brackets (S : String) return String is
+        (if Value.Family = Family_Inet6 then "[" & S & "]" else S);
    begin
-      return Image (Value.Addr) & ':' & Port (2 .. Port'Last);
+      return Ipv6_Brackets (Image (Value.Addr)) & ':' & Port (2 .. Port'Last);
    end Image;
 
    -----------
@@ -1456,10 +1654,11 @@ package body GNAT.Sockets is
       use Interfaces.C;
 
       Img    : aliased char_array := To_C (Image);
-      Addr   : aliased C.int;
       Res    : C.int;
       Result : Inet_Addr_Type;
-
+      IPv6   : constant Boolean := Is_IPv6_Address (Image);
+      Ia     : aliased In_Addr_Union
+                 (if IPv6 then Family_Inet6 else Family_Inet);
    begin
       --  Special case for an empty Image as on some platforms (e.g. Windows)
       --  calling Inet_Addr("") will not return an error.
@@ -1468,7 +1667,9 @@ package body GNAT.Sockets is
          Raise_Socket_Error (SOSC.EINVAL);
       end if;
 
-      Res := Inet_Pton (SOSC.AF_INET, Img'Address, Addr'Address);
+      Res := Inet_Pton
+        ((if IPv6 then SOSC.AF_INET6 else SOSC.AF_INET), Img'Address,
+         Ia'Address);
 
       if Res < 0 then
          Raise_Socket_Error (Socket_Errno);
@@ -1477,7 +1678,12 @@ package body GNAT.Sockets is
          Raise_Socket_Error (SOSC.EINVAL);
       end if;
 
-      To_Inet_Addr (To_In_Addr (Addr), Result);
+      if IPv6 then
+         To_Inet_Addr (Ia.In6, Result);
+      else
+         To_Inet_Addr (Ia.In4, Result);
+      end if;
+
       return Result;
    end Inet_Addr;
 
@@ -1527,6 +1733,16 @@ package body GNAT.Sockets is
       null;
    end Initialize;
 
+   ----------------
+   -- Is_Windows --
+   ----------------
+
+   function Is_Windows return Boolean is
+      use SOSC;
+   begin
+      return Target_OS = Windows;
+   end Is_Windows;
+
    --------------
    -- Is_Empty --
    --------------
@@ -1536,11 +1752,56 @@ package body GNAT.Sockets is
       return Item.Last = No_Socket;
    end Is_Empty;
 
-   -------------------
-   -- Is_IP_Address --
-   -------------------
+   ---------------------
+   -- Is_IPv6_Address --
+   ---------------------
+
+   function Is_IPv6_Address (Name : String) return Boolean is
+      Prev_Colon   : Natural := 0;
+      Double_Colon : Boolean := False;
+      Colons       : Natural := 0;
+   begin
+      for J in Name'Range loop
+         if Name (J) = ':' then
+            Colons := Colons + 1;
+
+            if Prev_Colon > 0 and then J = Prev_Colon + 1 then
+               if Double_Colon then
+                  --  Only one double colon allowed
+                  return False;
+               end if;
+
+               Double_Colon := True;
+
+            elsif J = Name'Last then
+               --  Single colon at the end is not allowed
+               return False;
+            end if;
+
+            Prev_Colon := J;
+
+         elsif Prev_Colon = Name'First then
+            --  Single colon at start is not allowed
+            return False;
+
+         elsif Name (J) = '.' then
+            return Prev_Colon > 0
+              and then Is_IPv4_Address (Name (Prev_Colon + 1 .. Name'Last));
+
+         elsif Name (J) not in '0' .. '9' | 'A' .. 'F' | 'a' .. 'f' then
+            return False;
+
+         end if;
+      end loop;
 
-   function Is_IP_Address (Name : String) return Boolean is
+      return Colons <= 7;
+   end Is_IPv6_Address;
+
+   ---------------------
+   -- Is_IPv4_Address --
+   ---------------------
+
+   function Is_IPv4_Address (Name : String) return Boolean is
       Dots : Natural := 0;
 
    begin
@@ -1571,7 +1832,7 @@ package body GNAT.Sockets is
       end loop;
 
       return Dots in 1 .. 3;
-   end Is_IP_Address;
+   end Is_IPv4_Address;
 
    -------------
    -- Is_Open --
@@ -1760,13 +2021,6 @@ package body GNAT.Sockets is
    ----------------------
 
    procedure Raise_Host_Error (H_Error : Integer; Name : String) is
-      function Dedot (Value : String) return String is
-        (if Value /= "" and then Value (Value'Last) = '.' then
-            Value (Value'First .. Value'Last - 1)
-         else
-            Value);
-      --  Removes dot at the end of error message
-
    begin
       raise Host_Error with
         Err_Code_Image (H_Error)
@@ -1863,7 +2117,7 @@ package body GNAT.Sockets is
       Flags  : Request_Flag_Type := No_Request_Flag)
    is
       Res : C.int;
-      Sin : aliased Sockaddr_In;
+      Sin : aliased Sockaddr;
       Len : aliased C.int := Sin'Size / 8;
 
    begin
@@ -1882,8 +2136,7 @@ package body GNAT.Sockets is
 
       Last := Last_Index (First => Item'First, Count => size_t (Res));
 
-      To_Inet_Addr (Sin.Sin_Addr, From.Addr);
-      From.Port := Port_Type (Network_To_Short (Sin.Sin_Port));
+      From := Get_Address (Sin);
    end Receive_Socket;
 
    --------------------
@@ -2142,17 +2395,13 @@ package body GNAT.Sockets is
    is
       Res  : C.int;
 
-      Sin  : aliased Sockaddr_In;
+      Sin  : aliased Sockaddr;
       C_To : System.Address;
       Len  : C.int;
 
    begin
       if To /= null then
-         Set_Family  (Sin.Sin_Family, To.Family);
-         Set_Address (Sin'Unchecked_Access, To_In_Addr (To.Addr));
-         Set_Port
-           (Sin'Unchecked_Access,
-            Short_To_Network (C.unsigned_short (To.Port)));
+         Set_Address (Sin'Unchecked_Access, To.all);
          C_To := Sin'Address;
          Len := Sin'Size / 8;
 
@@ -2294,9 +2543,9 @@ package body GNAT.Sockets is
       Level  : Level_Type := Socket_Level;
       Option : Option_Type)
    is
-      use SOSC;
       use type C.unsigned;
 
+      MR  : aliased IPV6_Mreq;
       V8  : aliased Two_Ints;
       V4  : aliased C.int;
       U4  : aliased C.unsigned;
@@ -2318,6 +2567,9 @@ package body GNAT.Sockets is
             | Keep_Alive
             | No_Delay
             | Reuse_Address
+            | Multicast_Loop_V4
+            | Multicast_Loop_V6
+            | IPv6_Only
          =>
             V4  := C.int (Boolean'Pos (Option.Enabled));
             Len := V4'Size / 8;
@@ -2346,26 +2598,42 @@ package body GNAT.Sockets is
             Len := V4'Size / 8;
             Add := V4'Address;
 
-         when Add_Membership
-            | Drop_Membership
+         when Add_Membership_V4
+            | Drop_Membership_V4
          =>
             V8 (V8'First) := To_Int (To_In_Addr (Option.Multicast_Address));
             V8 (V8'Last)  := To_Int (To_In_Addr (Option.Local_Interface));
             Len := V8'Size / 8;
             Add := V8'Address;
 
-         when Multicast_If =>
+         when Add_Membership_V6
+            | Drop_Membership_V6 =>
+            MR.ipv6mr_multiaddr := To_In6_Addr (Option.Multicast_Address);
+            MR.ipv6mr_interface := C.unsigned (Option.Interface_Index);
+            Len := MR'Size / 8;
+            Add := MR'Address;
+
+         when Multicast_If_V4 =>
             V4  := To_Int (To_In_Addr (Option.Outgoing_If));
             Len := V4'Size / 8;
             Add := V4'Address;
 
+         when Multicast_If_V6 =>
+            V4  := C.int (Option.Outgoing_If_Index);
+            Len := V4'Size / 8;
+            Add := V4'Address;
+
          when Multicast_TTL =>
             V1  := C.unsigned_char (Option.Time_To_Live);
             Len := V1'Size / 8;
             Add := V1'Address;
 
-         when Multicast_Loop
-            | Receive_Packet_Info
+         when Multicast_Hops =>
+            V4  := C.int (Option.Hop_Limit);
+            Len := V4'Size / 8;
+            Add := V4'Address;
+
+         when Receive_Packet_Info
          =>
             V1  := C.unsigned_char (Boolean'Pos (Option.Enabled));
             Len := V1'Size / 8;
@@ -2374,7 +2642,7 @@ package body GNAT.Sockets is
          when Receive_Timeout
             | Send_Timeout
          =>
-            if Target_OS = Windows then
+            if Is_Windows then
 
                --  On Windows, the timeout is a DWORD in milliseconds, and
                --  the actual timeout is 500 ms + the given value (unless it
@@ -2420,28 +2688,6 @@ package body GNAT.Sockets is
       end if;
    end Set_Socket_Option;
 
-   ----------------------
-   -- Short_To_Network --
-   ----------------------
-
-   function Short_To_Network (S : C.unsigned_short) return C.unsigned_short is
-      use type C.unsigned_short;
-
-   begin
-      --  Big-endian case. No conversion needed. On these platforms, htons()
-      --  defaults to a null procedure.
-
-      if Default_Bit_Order = High_Order_First then
-         return S;
-
-      --  Little-endian case. We must swap the high and low bytes of this
-      --  short to make the port number network compliant.
-
-      else
-         return (S / 256) + (S mod 256) * 256;
-      end if;
-   end Short_To_Network;
-
    ---------------------
    -- Shutdown_Socket --
    ---------------------
@@ -2538,15 +2784,18 @@ package body GNAT.Sockets is
    -------------------
 
    function To_Host_Entry (E : Hostent_Access) return Host_Entry_Type is
-      use type C.size_t;
-
       Aliases_Count, Addresses_Count : Natural;
 
-      --  H_Length is not used because it is currently only ever set to 4, as
-      --  we only handle the case of H_Addrtype being AF_INET.
+      Family : constant Family_Type :=
+                 (case Hostent_H_Addrtype (E) is
+                     when SOSC.AF_INET  => Family_Inet,
+                     when SOSC.AF_INET6 => Family_Inet6,
+                     when others        => Family_Unspec);
+
+      Addr_Len : constant C.size_t := C.size_t (Hostent_H_Length (E));
 
    begin
-      if Hostent_H_Addrtype (E) /= SOSC.AF_INET then
+      if Family = Family_Unspec then
          Raise_Socket_Error (SOSC.EPFNOSUPPORT);
       end if;
 
@@ -2574,61 +2823,35 @@ package body GNAT.Sockets is
 
          for J in Result.Addresses'Range loop
             declare
-               Addr : In_Addr;
+               Ia : In_Addr_Union (Family);
 
                --  Hostent_H_Addr (E, <index>) may return an address that is
                --  not correctly aligned for In_Addr, so we need to use
                --  an intermediate copy operation on a type with an alignment
                --  of 1 to recover the value.
 
-               subtype Addr_Buf_T is C.char_array (1 .. Addr'Size / 8);
+               subtype Addr_Buf_T is C.char_array (1 .. Addr_Len);
                Unaligned_Addr : Addr_Buf_T;
                for Unaligned_Addr'Address
                  use Hostent_H_Addr (E, C.int (J - Result.Addresses'First));
                pragma Import (Ada, Unaligned_Addr);
 
                Aligned_Addr : Addr_Buf_T;
-               for Aligned_Addr'Address use Addr'Address;
+               for Aligned_Addr'Address use Ia'Address;
                pragma Import (Ada, Aligned_Addr);
 
             begin
                Aligned_Addr := Unaligned_Addr;
-               To_Inet_Addr (Addr, Result.Addresses (J));
+               if Family = Family_Inet6 then
+                  To_Inet_Addr (Ia.In6, Result.Addresses (J));
+               else
+                  To_Inet_Addr (Ia.In4, Result.Addresses (J));
+               end if;
             end;
          end loop;
       end return;
    end To_Host_Entry;
 
-   ----------------
-   -- To_In_Addr --
-   ----------------
-
-   function To_In_Addr (Addr : Inet_Addr_Type) return In_Addr is
-   begin
-      if Addr.Family = Family_Inet then
-         return (S_B1 => C.unsigned_char (Addr.Sin_V4 (1)),
-                 S_B2 => C.unsigned_char (Addr.Sin_V4 (2)),
-                 S_B3 => C.unsigned_char (Addr.Sin_V4 (3)),
-                 S_B4 => C.unsigned_char (Addr.Sin_V4 (4)));
-      end if;
-
-      raise Socket_Error with "IPv6 not supported";
-   end To_In_Addr;
-
-   ------------------
-   -- To_Inet_Addr --
-   ------------------
-
-   procedure To_Inet_Addr
-     (Addr   : In_Addr;
-      Result : out Inet_Addr_Type) is
-   begin
-      Result.Sin_V4 (1) := Inet_Addr_Comp_Type (Addr.S_B1);
-      Result.Sin_V4 (2) := Inet_Addr_Comp_Type (Addr.S_B2);
-      Result.Sin_V4 (3) := Inet_Addr_Comp_Type (Addr.S_B3);
-      Result.Sin_V4 (4) := Inet_Addr_Comp_Type (Addr.S_B4);
-   end To_Inet_Addr;
-
    ------------
    -- To_Int --
    ------------
@@ -2825,7 +3048,8 @@ package body GNAT.Sockets is
    is
      (case Family is
          when Family_Inet => (Family_Inet, Bytes),
-         when Family_Inet6 => (Family_Inet6, Bytes));
+         when Family_Inet6 => (Family_Inet6, Bytes),
+         when Family_Unspec => (Family => Family_Unspec));
 
    ---------------
    -- Get_Bytes --
@@ -2834,7 +3058,8 @@ package body GNAT.Sockets is
    function Get_Bytes (Addr : Inet_Addr_Type) return Inet_Addr_Bytes is
      (case Addr.Family is
          when Family_Inet => Addr.Sin_V4,
-         when Family_Inet6 => Addr.Sin_V6);
+         when Family_Inet6 => Addr.Sin_V6,
+         when Family_Unspec => (1 .. 0 => 0));
 
    ----------
    -- Mask --

gcc/ada/libgnat/g-socket.ads

@@ -469,13 +469,17 @@ package GNAT.Sockets is
    --  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);
+   type Family_Type is (Family_Inet, Family_Inet6, Family_Unspec);
    --  Address family (or protocol family) identifies the communication domain
    --  and groups protocols with similar address formats.
+   --  The order of the enumeration elements should not be changed unilaterally
+   --  because the IPv6_TCP_Preferred routine rely on it.
 
    type Mode_Type is (Socket_Stream, Socket_Datagram);
    --  Stream sockets provide connection-oriented byte streams. Datagram
    --  sockets support unreliable connectionless message based communication.
+   --  The order of the enumeration elements should not be changed unilaterally
+   --  because the IPv6_TCP_Preferred routine rely on it.
 
    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
@@ -497,8 +501,8 @@ package GNAT.Sockets is
    type Inet_Addr_Comp_Type is mod 2 ** 8;
    --  Octet for Internet address
 
-   Inet_Addr_Bytes_Length : constant array (Family_Type) of Positive :=
-     (Family_Inet => 4, Family_Inet6 => 16);
+   Inet_Addr_Bytes_Length : constant array (Family_Type) of Natural :=
+     (Family_Inet => 4, Family_Inet6 => 16, Family_Unspec => 0);
 
    type Inet_Addr_Bytes is array (Natural range <>) of Inet_Addr_Comp_Type;
 
@@ -517,24 +521,61 @@ package GNAT.Sockets is
 
          when Family_Inet6 =>
             Sin_V6 : Inet_Addr_V6_Type := (others => 0);
+
+         when Family_Unspec =>
+            null;
+
       end case;
    end record;
 
    --  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.
+   --  and IPv6 contains 16 octets).
 
    Any_Inet_Addr       : constant Inet_Addr_Type;
+   --  Wildcard enabling all addresses to use with bind
+
+   Any_Inet6_Addr      : constant Inet_Addr_Type;
+   --  Idem for IPV6 socket
+
    No_Inet_Addr        : constant Inet_Addr_Type;
+   --  Uninitialized inet address
+
+   Unspecified_Addr    : constant Inet_Addr_Type;
+   --  Unspecified address. Unlike of No_Inet_Addr the constraint is
+   --  Family_Unspec for this constant.
+
    Broadcast_Inet_Addr : constant Inet_Addr_Type;
+   --  Broadcast destination address in the current network
+
    Loopback_Inet_Addr  : constant Inet_Addr_Type;
+   --  Loopback address to the local host
 
-   --  Useful constants for IPv4 multicast addresses
+   Loopback_Inet6_Addr : constant Inet_Addr_Type;
+   --  IPv6 Loopback address to the local host
+
+   --  Useful constants for multicast addresses
 
    Unspecified_Group_Inet_Addr  : constant Inet_Addr_Type;
+   --  IPv4 multicast mask with prefix length 4
+
+   Unspecified_Group_Inet6_Addr : constant Inet_Addr_Type;
+   --  IPv6 multicast mask with prefix length 16
+
    All_Hosts_Group_Inet_Addr    : constant Inet_Addr_Type;
+   --  Multicast group addresses all hosts on the same network segment
+
+   All_Hosts_Group_Inet6_Addr   : constant Inet_Addr_Type;
+   --  Idem for IPv6 protocol
+
    All_Routers_Group_Inet_Addr  : constant Inet_Addr_Type;
+   --  Multicast group addresses all routers on the same network segment
+
+   All_Routers_Group_Inet6_Addr : constant Inet_Addr_Type;
+   --  Idem for IPv6 protocol
+
+   IPv4_To_IPv6_Prefix : constant Inet_Addr_Bytes :=
+     (1 .. 10 => 0, 11 .. 12 => 255);
+   --  Prefix for IPv4 mapped to IPv6 addresses
 
    --  Functions to handle masks and prefixes
 
@@ -563,18 +604,24 @@ package GNAT.Sockets is
    --  for uninitialized socket addresses.
 
    No_Sock_Addr : constant Sock_Addr_Type;
+   --  Uninitialized socket address
+
+   function Is_IPv4_Address (Name : String) return Boolean;
+   --  Return true when Name is an IPv4 address in dotted quad notation
+
+   function Is_IPv6_Address (Name : String) return Boolean;
+   --  Return true when Name is an IPv6 address in numeric format
 
    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).
+   --  8 hextets in hexadecimal format separated by colons.
 
    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
+   --  Convert address image from numbers-dots-and-colons notation into an
    --  inet address.
 
    --  Host entries provide complete information on a given host: the official
@@ -723,6 +770,7 @@ package GNAT.Sockets is
    type Level_Type is
      (Socket_Level,
       IP_Protocol_For_IP_Level,
+      IP_Protocol_For_IPv6_Level,
       IP_Protocol_For_UDP_Level,
       IP_Protocol_For_TCP_Level);
 
@@ -740,18 +788,29 @@ package GNAT.Sockets is
       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
+      Add_Membership_V4,   -- Join a multicast group
+      Add_Membership_V6,   -- Idem for IPv6 socket
+      Drop_Membership_V4,  -- Leave a multicast group
+      Drop_Membership_V6,  -- Idem for IPv6 socket
+      Multicast_If_V4,     -- Set default out interface for multicast packets
+      Multicast_If_V6,     -- Idem for IPv6 socket
+      Multicast_Loop_V4,   -- Sent multicast packets are looped to local socket
+      Multicast_Loop_V6,   -- Idem for IPv6 socket
       Multicast_TTL,       -- Set the time-to-live of sent multicast packets
-      Multicast_Loop,      -- Sent multicast packets are looped to local socket
+      Multicast_Hops,      -- Set the multicast hop limit for the IPv6 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
+      IPv6_Only,           -- Restricted to IPv6 communications only
       Busy_Polling);       -- Set busy polling mode
    subtype Specific_Option_Name is
      Option_Name range Keep_Alive .. Option_Name'Last;
 
+   Add_Membership  : Option_Name renames Add_Membership_V4;
+   Drop_Membership : Option_Name renames Drop_Membership_V4;
+   Multicast_If    : Option_Name renames Multicast_If_V4;
+   Multicast_Loop  : Option_Name renames Multicast_Loop_V4;
+
    type Option_Type (Name : Option_Name := Keep_Alive) is record
       case Name is
          when Generic_Option =>
@@ -764,7 +823,9 @@ package GNAT.Sockets is
               Linger              |
               No_Delay            |
               Receive_Packet_Info |
-              Multicast_Loop      =>
+              IPv6_Only           |
+              Multicast_Loop_V4   |
+              Multicast_Loop_V6   =>
             Enabled : Boolean;
 
             case Name is
@@ -784,17 +845,31 @@ package GNAT.Sockets is
          when Error           =>
             Error : Error_Type;
 
-         when Add_Membership  |
-              Drop_Membership =>
+         when Add_Membership_V4  |
+              Add_Membership_V6  |
+              Drop_Membership_V4 |
+              Drop_Membership_V6 =>
             Multicast_Address : Inet_Addr_Type;
+            case Name is
+               when Add_Membership_V4  |
+                    Drop_Membership_V4 =>
                   Local_Interface : Inet_Addr_Type;
+               when others =>
+                  Interface_Index : Natural;
+            end case;
 
-         when Multicast_If    =>
+         when Multicast_If_V4 =>
             Outgoing_If : Inet_Addr_Type;
 
+         when Multicast_If_V6 =>
+            Outgoing_If_Index : Natural;
+
          when Multicast_TTL  =>
             Time_To_Live : Natural;
 
+         when Multicast_Hops =>
+            Hop_Limit : Integer range -1 .. 255;
+
          when Send_Timeout |
               Receive_Timeout =>
             Timeout : Timeval_Duration;
@@ -865,10 +940,76 @@ package GNAT.Sockets is
 
    type Vector_Type is array (Integer range <>) of Vector_Element;
 
+   type Address_Info is record
+      Addr  : Sock_Addr_Type;
+      Mode  : Mode_Type  := Socket_Stream;
+      Level : Level_Type := IP_Protocol_For_IP_Level;
+   end record;
+
+   type Address_Info_Array is array (Positive range <>) of Address_Info;
+
+   function Get_Address_Info
+     (Host         : String;
+      Service      : String;
+      Family       : Family_Type := Family_Unspec;
+      Mode         : Mode_Type   := Socket_Stream;
+      Level        : Level_Type  := IP_Protocol_For_IP_Level;
+      Numeric_Host : Boolean     := False;
+      Passive      : Boolean     := False;
+      Unknown      : access procedure
+        (Family, Mode, Level, Length : Integer) := null)
+      return Address_Info_Array;
+   --  Returns available addresses for the Host and Service names.
+   --  If Family is Family_Unspec, all available protocol families returned.
+   --  Service is the name of service as defined in /etc/services or port
+   --  number in string representation.
+   --  If Unknown procedure access specified it will be called in case of
+   --  unknown family found.
+   --  Numeric_Host flag suppresses any potentially lengthy network host
+   --  address lookups, and Host have to represent numerical network address in
+   --  this case.
+   --  If Passive is True and Host is empty then the returned socket addresses
+   --  will be suitable for binding a socket that will accept connections.
+   --  The returned socket address will contain  the  "wildcard  address".
+   --  The wildcard address is used by applications (typically servers) that
+   --  intend to accept connections on any of the hosts's network addresses.
+   --  If Host is not empty, then the Passive flag is ignored.
+   --  If Passive is False, then the returned socket addresses will be suitable
+   --  for use with connect, sendto, or sendmsg.  If Host is empty, then the
+   --  network address will be set  to  the  loopback  interface  address;
+   --  this is used by applications that intend to communicate with peers
+   --  running on the same host.
+
+   procedure Sort
+     (Addr_Info : in out Address_Info_Array;
+      Compare   : access function (Left, Right : Address_Info) return Boolean);
+   --  Sort address info array in order defined by compare function
+
+   function IPv6_TCP_Preferred (Left, Right : Address_Info) return Boolean;
+   --  To use with Sort to order where IPv6 and TCP addresses first
+
+   type Host_Service (Host_Length, Service_Length : Natural) is record
+      Host    : String (1 .. Host_Length);
+      Service : String (1 .. Service_Length);
+   end record;
+
+   function Get_Name_Info
+     (Addr         : Sock_Addr_Type;
+      Numeric_Host : Boolean := False;
+      Numeric_Serv : Boolean := False) return Host_Service;
+   --  Returns host and service names by the address and port.
+   --  If Numeric_Host is True, then the numeric form of the hostname is
+   --  returned. When Numeric_Host is False, this will still happen in case the
+   --  host name cannot be determined.
+   --  If Numenric_Serv is True, then the numeric form of the service address
+   --  (port number) is returned.  When Numenric_Serv is False, this will still
+   --  happen in case the service's name cannot be determined.
+
    procedure Create_Socket
      (Socket : out Socket_Type;
       Family : Family_Type := Family_Inet;
-      Mode   : Mode_Type   := Socket_Stream);
+      Mode   : Mode_Type   := Socket_Stream;
+      Level  : Level_Type  := IP_Protocol_For_IP_Level);
    --  Create an endpoint for communication. Raises Socket_Error on error
 
    procedure Accept_Socket
@@ -1265,12 +1406,19 @@ private
 
    Any_Inet_Addr       : constant Inet_Addr_Type :=
                            (Family_Inet, (others => 0));
+   Any_Inet6_Addr      : constant Inet_Addr_Type :=
+                           (Family_Inet6, (others => 0));
    No_Inet_Addr        : constant Inet_Addr_Type :=
                            (Family_Inet, (others => 0));
+   Unspecified_Addr    : constant Inet_Addr_Type :=
+                           (Family => Family_Unspec);
    Broadcast_Inet_Addr : constant Inet_Addr_Type :=
                            (Family_Inet, (others => 255));
    Loopback_Inet_Addr  : constant Inet_Addr_Type :=
                            (Family_Inet, (127, 0, 0, 1));
+   Loopback_Inet6_Addr : constant Inet_Addr_Type :=
+                           (Family_Inet6,
+                            (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1));
 
    Unspecified_Group_Inet_Addr : constant Inet_Addr_Type :=
                                    (Family_Inet, (224, 0, 0, 0));
@@ -1279,6 +1427,13 @@ private
    All_Routers_Group_Inet_Addr : constant Inet_Addr_Type :=
                                    (Family_Inet, (224, 0, 0, 2));
 
+   Unspecified_Group_Inet6_Addr : constant Inet_Addr_Type :=
+     (Family_Inet6, (255, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+   All_Hosts_Group_Inet6_Addr   : constant Inet_Addr_Type :=
+     (Family_Inet6, (255, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1));
+   All_Routers_Group_Inet6_Addr : constant Inet_Addr_Type :=
+     (Family_Inet6, (255, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2));
+
    No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
 
    Max_Name_Length : constant := 64;
@@ -1291,8 +1446,8 @@ private
    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 Name_Array is array (Positive range <>) of Name_Type;
+   type Inet_Addr_Array is array (Positive range <>) of Inet_Addr_Type;
 
    type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is record
       Official  : Name_Type;

gcc/ada/libgnat/g-sothco.adb

@@ -36,13 +36,52 @@ package body GNAT.Sockets.Thin_Common is
    -----------------
 
    procedure Set_Address
-     (Sin     : Sockaddr_In_Access;
-      Address : In_Addr)
+     (Sin     : Sockaddr_Access;
+      Address : Sock_Addr_Type)
    is
    begin
-      Sin.Sin_Addr := Address;
+      Set_Family (Sin.Sin_Family, Address.Family);
+      Sin.Sin_Port := Short_To_Network (C.unsigned_short (Address.Port));
+
+      case Address.Family is
+         when Family_Inet =>
+            Sin.Sin_Addr := To_In_Addr (Address.Addr);
+         when Family_Inet6 =>
+            Sin.Sin6_Addr := To_In6_Addr (Address.Addr);
+            Sin.Sin6_Scope_Id := 0;
+         when Family_Unspec =>
+            null;
+      end case;
    end Set_Address;
 
+   -----------------
+   -- Get_Address --
+   -----------------
+
+   function Get_Address (Sin : Sockaddr) return Sock_Addr_Type is
+      Family : constant C.unsigned_short :=
+        (if SOSC.Has_Sockaddr_Len = 0 then Sin.Sin_Family.Short_Family
+         else C.unsigned_short (Sin.Sin_Family.Char_Family));
+      Result : Sock_Addr_Type
+        (case Family is
+            when SOSC.AF_INET6 => Family_Inet6,
+            when SOSC.AF_INET  => Family_Inet,
+            when others        => Family_Unspec);
+   begin
+      Result.Port := Port_Type (Network_To_Short (Sin.Sin_Port));
+
+      case Result.Family is
+         when Family_Inet =>
+            To_Inet_Addr (Sin.Sin_Addr, Result.Addr);
+         when Family_Inet6 =>
+            To_Inet_Addr (Sin.Sin6_Addr, Result.Addr);
+         when Family_Unspec =>
+            Result.Addr := (Family => Family_Unspec);
+      end case;
+
+      return Result;
+   end Get_Address;
+
    ----------------
    -- Set_Family --
    ----------------
@@ -62,16 +101,88 @@ package body GNAT.Sockets.Thin_Common is
       end if;
    end Set_Family;
 
-   --------------
-   -- Set_Port --
-   --------------
+   ----------------
+   -- To_In_Addr --
+   ----------------
+
+   function To_In_Addr (Addr : Inet_Addr_Type) return In_Addr is
+   begin
+      if Addr.Family = Family_Inet then
+         return (S_B1 => C.unsigned_char (Addr.Sin_V4 (1)),
+                 S_B2 => C.unsigned_char (Addr.Sin_V4 (2)),
+                 S_B3 => C.unsigned_char (Addr.Sin_V4 (3)),
+                 S_B4 => C.unsigned_char (Addr.Sin_V4 (4)));
+      end if;
+
+      raise Socket_Error with "IPv6 not supported";
+   end To_In_Addr;
+
+   ------------------
+   -- To_Inet_Addr --
+   ------------------
+
+   procedure To_Inet_Addr
+     (Addr   : In_Addr;
+      Result : out Inet_Addr_Type) is
+   begin
+      Result.Sin_V4 (1) := Inet_Addr_Comp_Type (Addr.S_B1);
+      Result.Sin_V4 (2) := Inet_Addr_Comp_Type (Addr.S_B2);
+      Result.Sin_V4 (3) := Inet_Addr_Comp_Type (Addr.S_B3);
+      Result.Sin_V4 (4) := Inet_Addr_Comp_Type (Addr.S_B4);
+   end To_Inet_Addr;
+
+   ------------------
+   -- To_Inet_Addr --
+   ------------------
 
-   procedure Set_Port
-     (Sin  : Sockaddr_In_Access;
-      Port : C.unsigned_short)
+   procedure To_Inet_Addr
+     (Addr   : In6_Addr;
+      Result : out Inet_Addr_Type)
    is
+      Sin_V6 : Inet_Addr_V6_Type;
    begin
-      Sin.Sin_Port := Port;
-   end Set_Port;
+      for J in Addr'Range loop
+         Sin_V6 (J) := Inet_Addr_Comp_Type (Addr (J));
+      end loop;
+
+      Result := (Family => Family_Inet6, Sin_V6 => Sin_V6);
+   end To_Inet_Addr;
+
+   ----------------
+   -- To_In_Addr --
+   ----------------
+
+   function To_In6_Addr (Addr : Inet_Addr_Type) return In6_Addr is
+      Result : In6_Addr;
+   begin
+      for J in Addr.Sin_V6'Range loop
+         Result (J) := C.unsigned_char (Addr.Sin_V6 (J));
+      end loop;
+
+      return Result;
+   end To_In6_Addr;
+
+   ----------------------
+   -- Short_To_Network --
+   ----------------------
+
+   function Short_To_Network (S : C.unsigned_short) return C.unsigned_short is
+      use Interfaces;
+      use System;
+
+   begin
+      --  Big-endian case. No conversion needed. On these platforms, htons()
+      --  defaults to a null procedure.
+
+      if Default_Bit_Order = High_Order_First then
+         return S;
+
+      --  Little-endian case. We must swap the high and low bytes of this
+      --  short to make the port number network compliant.
+
+      else
+         return C.unsigned_short (Rotate_Left (Unsigned_16 (S), 8));
+      end if;
+   end Short_To_Network;
 
 end GNAT.Sockets.Thin_Common;

gcc/ada/libgnat/g-sothco.ads

@@ -33,13 +33,12 @@
 --  This package should not be directly with'ed by an applications program.
 
 with Ada.Unchecked_Conversion;
-
-with Interfaces.C;
-with Interfaces.C.Pointers;
+with Interfaces.C.Strings;
 
 package GNAT.Sockets.Thin_Common is
 
    package C renames Interfaces.C;
+   package CS renames C.Strings;
 
    Success : constant C.int :=  0;
    Failure : constant C.int := -1;
@@ -65,6 +64,9 @@ package GNAT.Sockets.Thin_Common is
    type Timeval_Access is access all Timeval;
    pragma Convention (C, Timeval_Access);
 
+   type socklen_t is mod 2 ** (8 * SOSC.SIZEOF_socklen_t);
+   for socklen_t'Size use (8 * SOSC.SIZEOF_socklen_t);
+
    Immediat : constant Timeval := (0, 0);
 
    -------------------------------------------
@@ -72,11 +74,13 @@ package GNAT.Sockets.Thin_Common is
    -------------------------------------------
 
    Families : constant array (Family_Type) of C.int :=
-                (Family_Inet  => SOSC.AF_INET,
+                (Family_Unspec => SOSC.AF_UNSPEC,
+                 Family_Inet   => SOSC.AF_INET,
                  Family_Inet6  => SOSC.AF_INET6);
 
    Lengths  : constant array (Family_Type) of C.unsigned_char :=
-                (Family_Inet  => SOSC.SIZEOF_sockaddr_in,
+                (Family_Unspec => 0,
+                 Family_Inet   => SOSC.SIZEOF_sockaddr_in,
                  Family_Inet6  => SOSC.SIZEOF_sockaddr_in6);
 
    ----------------------------
@@ -112,22 +116,6 @@ package GNAT.Sockets.Thin_Common is
    --  Set the family component to the appropriate value for Family, and also
    --  set Length accordingly if applicable on this platform.
 
-   type Sockaddr is record
-      Sa_Family : Sockaddr_Length_And_Family;
-      --  Address family (and address length on some platforms)
-
-      Sa_Data : C.char_array (1 .. 14) := (others => C.nul);
-      --  Family-specific data
-      --  Note that some platforms require that all unused (reserved) bytes
-      --  in addresses be initialized to 0 (e.g. VxWorks).
-   end record;
-   pragma Convention (C, Sockaddr);
-   --  Generic socket address
-
-   type Sockaddr_Access is access all Sockaddr;
-   pragma Convention (C, Sockaddr_Access);
-   --  Access to socket address
-
    ----------------------------
    -- AF_INET socket address --
    ----------------------------
@@ -144,29 +132,32 @@ package GNAT.Sockets.Thin_Common is
    function To_In_Addr is new Ada.Unchecked_Conversion (C.int, In_Addr);
    function To_Int     is new Ada.Unchecked_Conversion (In_Addr, C.int);
 
-   type In_Addr_Access is access all In_Addr;
-   pragma Convention (C, In_Addr_Access);
-   --  Access to internet address
+   function To_In_Addr (Addr : Inet_Addr_Type) return In_Addr;
+   procedure To_Inet_Addr
+     (Addr   : In_Addr;
+      Result : out Inet_Addr_Type);
+   --  Conversion functions
 
-   Inaddr_Any : aliased constant In_Addr := (others => 0);
-   --  Any internet address (all the interfaces)
+   type In6_Addr is array (1 .. 16) of C.unsigned_char;
+   for In6_Addr'Alignment use C.int'Alignment;
+   pragma Convention (C, In6_Addr);
 
-   type In_Addr_Access_Array is array (C.size_t range <>)
-     of aliased In_Addr_Access;
-   pragma Convention (C, In_Addr_Access_Array);
+   function To_In6_Addr (Addr : Inet_Addr_Type) return In6_Addr;
+   procedure To_Inet_Addr
+     (Addr   : In6_Addr;
+      Result : out Inet_Addr_Type);
+   --  Conversion functions
 
-   package In_Addr_Access_Pointers is new C.Pointers
-     (C.size_t, In_Addr_Access, In_Addr_Access_Array, null);
-   --  Array of internet addresses
-
-   type Sockaddr_In is record
+   type Sockaddr (Family : Family_Type := Family_Inet) is record
       Sin_Family : Sockaddr_Length_And_Family;
       --  Address family (and address length on some platforms)
 
       Sin_Port : C.unsigned_short;
       --  Port in network byte order
 
-      Sin_Addr : In_Addr;
+      case Family is
+      when Family_Inet =>
+         Sin_Addr : In_Addr := (others => 0);
          --  IPv4 address
 
          Sin_Zero : C.char_array (1 .. 8) := (others => C.nul);
@@ -174,25 +165,31 @@ package GNAT.Sockets.Thin_Common is
          --
          --  Note that some platforms require that all unused (reserved) bytes
          --  in addresses be initialized to 0 (e.g. VxWorks).
+      when Family_Inet6 =>
+         Sin6_FlowInfo : Interfaces.Unsigned_32 := 0;
+         Sin6_Addr     : In6_Addr := (others => 0);
+         Sin6_Scope_Id : Interfaces.Unsigned_32 := 0;
+      when Family_Unspec =>
+         null;
+      end case;
    end record;
-   pragma Convention (C, Sockaddr_In);
+   pragma Unchecked_Union (Sockaddr);
+   pragma Convention (C, Sockaddr);
    --  Internet socket address
 
-   type Sockaddr_In_Access is access all Sockaddr_In;
-   pragma Convention (C, Sockaddr_In_Access);
+   type Sockaddr_Access is access all Sockaddr;
+   pragma Convention (C, Sockaddr_Access);
    --  Access to internet socket address
 
-   procedure Set_Port
-     (Sin  : Sockaddr_In_Access;
-      Port : C.unsigned_short);
-   pragma Inline (Set_Port);
-   --  Set Sin.Sin_Port to Port
-
    procedure Set_Address
-     (Sin     : Sockaddr_In_Access;
-      Address : In_Addr);
-   pragma Inline (Set_Address);
-   --  Set Sin.Sin_Addr to Address
+     (Sin     : Sockaddr_Access;
+      Address : Sock_Addr_Type);
+   --  Initialise all necessary fields in Sin from Address.
+   --  Set appropriate Family, Port, and either Sin.Sin_Addr or Sin.Sin6_Addr
+   --  depend on family.
+
+   function Get_Address (Sin : Sockaddr) return Sock_Addr_Type;
+   --  Get Sock_Addr_Type from Sockaddr
 
    ------------------
    -- Host entries --
@@ -297,6 +294,51 @@ package GNAT.Sockets.Thin_Common is
       Buf    : System.Address;
       Buflen : C.int) return C.int;
 
+   Address_Size : constant := Standard'Address_Size;
+
+   type Addrinfo;
+   type Addrinfo_Access is access all Addrinfo;
+
+   type Addrinfo is record
+      ai_flags     : C.int;
+      ai_family    : C.int;
+      ai_socktype  : C.int;
+      ai_protocol  : C.int;
+      ai_addrlen   : socklen_t;
+      ai_addr      : Sockaddr_Access;
+      ai_canonname : CS.char_array_access;
+      ai_next      : Addrinfo_Access;
+   end record with Convention => C;
+   for Addrinfo use record
+      ai_flags     at SOSC.AI_FLAGS_OFFSET     range 0 .. C.int'Size - 1;
+      ai_family    at SOSC.AI_FAMILY_OFFSET    range 0 .. C.int'Size - 1;
+      ai_socktype  at SOSC.AI_SOCKTYPE_OFFSET  range 0 .. C.int'Size - 1;
+      ai_protocol  at SOSC.AI_PROTOCOL_OFFSET  range 0 .. C.int'Size - 1;
+      ai_addrlen   at SOSC.AI_ADDRLEN_OFFSET   range 0 .. socklen_t'Size - 1;
+      ai_canonname at SOSC.AI_CANONNAME_OFFSET range 0 .. Address_Size - 1;
+      ai_addr      at SOSC.AI_ADDR_OFFSET      range 0 .. Address_Size - 1;
+      ai_next      at SOSC.AI_NEXT_OFFSET      range 0 .. Address_Size - 1;
+   end record;
+
+   function C_Getaddrinfo
+     (Node    : CS.char_array_access;
+      Service : CS.char_array_access;
+      Hints   : access constant Addrinfo;
+      Res     : not null access Addrinfo_Access) return C.int;
+
+   procedure C_Freeaddrinfo (res : Addrinfo_Access);
+
+   function C_Getnameinfo
+     (sa      : Sockaddr_Access;
+      salen   : socklen_t;
+      host    : CS.char_array_access;
+      hostlen : C.size_t;
+      serv    : CS.char_array_access;
+      servlen : C.size_t;
+      flags   : C.int) return C.int;
+
+   function C_GAI_Strerror (ecode : C.int) return CS.chars_ptr;
+
    ------------------------------------
    -- Scatter/gather vector handling --
    ------------------------------------
@@ -375,11 +417,27 @@ package GNAT.Sockets.Thin_Common is
       Cp  : System.Address;
       Inp : System.Address) return C.int;
 
+   function Inet_Ntop
+     (Af   : C.int;
+      Src  : System.Address;
+      Dst  : CS.char_array_access;
+      Size : socklen_t) return CS.char_array_access;
+
    function C_Ioctl
      (Fd  : C.int;
       Req : SOSC.IOCTL_Req_T;
       Arg : access C.int) return C.int;
 
+   function Short_To_Network
+     (S : C.unsigned_short) return C.unsigned_short;
+   pragma Inline (Short_To_Network);
+   --  Convert a port number into a network port number
+
+   function Network_To_Short
+     (S : C.unsigned_short) return C.unsigned_short
+   renames Short_To_Network;
+   --  Symmetric operation
+
 private
    pragma Import (C, Get_Socket_From_Set, "__gnat_get_socket_from_set");
    pragma Import (C, Is_Socket_In_Set, "__gnat_is_socket_in_set");
@@ -389,12 +447,18 @@ private
    pragma Import (C, Reset_Socket_Set, "__gnat_reset_socket_set");
    pragma Import (C, C_Ioctl, "__gnat_socket_ioctl");
    pragma Import (C, Inet_Pton, SOSC.Inet_Pton_Linkname);
+   pragma Import (C, Inet_Ntop, SOSC.Inet_Ntop_Linkname);
 
    pragma Import (C, C_Gethostbyname, "__gnat_gethostbyname");
    pragma Import (C, C_Gethostbyaddr, "__gnat_gethostbyaddr");
    pragma Import (C, C_Getservbyname, "__gnat_getservbyname");
    pragma Import (C, C_Getservbyport, "__gnat_getservbyport");
 
+   pragma Import (C, C_Getaddrinfo,   "__gnat_getaddrinfo");
+   pragma Import (C, C_Freeaddrinfo,  "__gnat_freeaddrinfo");
+   pragma Import (C, C_Getnameinfo,   "__gnat_getnameinfo");
+   pragma Import (C, C_GAI_Strerror,  "__gnat_gai_strerror");
+
    pragma Import (C, Servent_S_Name,  "__gnat_servent_s_name");
    pragma Import (C, Servent_S_Alias, "__gnat_servent_s_alias");
    pragma Import (C, Servent_S_Port,  "__gnat_servent_s_port");

gcc/ada/libgnat/g-stsifd__sockets.adb

@@ -60,7 +60,7 @@ package body Signalling_Fds is
       L_Sock, R_Sock, W_Sock : C.int := Failure;
       --  Listening socket, read socket and write socket
 
-      Sin : aliased Sockaddr_In;
+      Sin : aliased Sockaddr;
       Len : aliased C.int;
       --  Address of listening socket
 

gcc/ada/s-oscons-tmplt.c

@@ -1056,6 +1056,138 @@ CND(AF_INET, "IPv4 address family")
 #endif
 CND(AF_INET6, "IPv6 address family")
 
+#ifndef AF_UNSPEC
+# define AF_UNSPEC -1
+#else
+# define HAVE_AF_UNSPEC 1
+#endif
+CND(AF_UNSPEC, "Unspecified address family")
+
+/*
+
+   -----------------------------
+   -- addrinfo fields offsets --
+   -----------------------------
+
+*/
+
+#ifdef AI_CANONNAME
+  const struct addrinfo ai;
+
+#define AI_FLAGS_OFFSET ((void *)&ai.ai_flags - (void *)&ai)
+#define AI_FAMILY_OFFSET ((void *)&ai.ai_family - (void *)&ai)
+#define AI_SOCKTYPE_OFFSET ((void *)&ai.ai_socktype - (void *)&ai)
+#define AI_PROTOCOL_OFFSET ((void *)&ai.ai_protocol - (void *)&ai)
+#define AI_ADDRLEN_OFFSET ((void *)&ai.ai_addrlen - (void *)&ai)
+#define AI_ADDR_OFFSET ((void *)&ai.ai_addr - (void *)&ai)
+#define AI_CANONNAME_OFFSET ((void *)&ai.ai_canonname - (void *)&ai)
+#define AI_NEXT_OFFSET ((void *)&ai.ai_next - (void *)&ai)
+
+#else
+
+#define AI_FLAGS_OFFSET 0
+#define AI_FAMILY_OFFSET 4
+#define AI_SOCKTYPE_OFFSET 8
+#define AI_PROTOCOL_OFFSET 12
+#define AI_ADDRLEN_OFFSET 16
+#define AI_CANONNAME_OFFSET 24
+#define AI_ADDR_OFFSET 32
+#define AI_NEXT_OFFSET 40
+
+#endif
+
+CND(AI_FLAGS_OFFSET,     "Offset of ai_flags in addrinfo");
+CND(AI_FAMILY_OFFSET,    "Offset of ai_family in addrinfo");
+CND(AI_SOCKTYPE_OFFSET,  "Offset of ai_socktype in addrinfo");
+CND(AI_PROTOCOL_OFFSET,  "Offset of ai_protocol in addrinfo");
+CND(AI_ADDRLEN_OFFSET,   "Offset of ai_addrlen in addrinfo");
+CND(AI_ADDR_OFFSET,      "Offset of ai_addr in addrinfo");
+CND(AI_CANONNAME_OFFSET, "Offset of ai_canonname in addrinfo");
+CND(AI_NEXT_OFFSET,      "Offset of ai_next in addrinfo");
+
+/*
+
+   ---------------------------------------
+   -- getaddrinfo getnameinfo constants --
+   ---------------------------------------
+
+*/
+
+#ifndef AI_PASSIVE
+# define AI_PASSIVE -1
+#endif
+CND(AI_PASSIVE, "NULL nodename for accepting")
+
+#ifndef AI_CANONNAME
+# define AI_CANONNAME -1
+#endif
+CND(AI_CANONNAME, "Get the host official name")
+
+#ifndef AI_NUMERICSERV
+# define AI_NUMERICSERV -1
+#endif
+CND(AI_NUMERICSERV, "Service is a numeric string")
+
+#ifndef AI_NUMERICHOST
+# define AI_NUMERICHOST -1
+#endif
+CND(AI_NUMERICHOST, "Node is a numeric IP address")
+
+#ifndef AI_ADDRCONFIG
+# define AI_ADDRCONFIG -1
+#endif
+CND(AI_ADDRCONFIG, "Returns addresses for only locally configured families")
+
+#ifndef AI_V4MAPPED
+# define AI_V4MAPPED -1
+#endif
+CND(AI_V4MAPPED, "Returns IPv4 mapped to IPv6")
+
+#ifndef AI_ALL
+# define AI_ALL -1
+#endif
+CND(AI_ALL, "Change AI_V4MAPPED behavior for unavailavle IPv6 addresses")
+
+#ifndef NI_NAMEREQD
+# define NI_NAMEREQD -1
+#endif
+CND(NI_NAMEREQD, "Error if the hostname cannot be determined")
+
+#ifndef NI_DGRAM
+# define NI_DGRAM -1
+#endif
+CND(NI_DGRAM, "Service is datagram")
+
+#ifndef NI_NOFQDN
+# define NI_NOFQDN -1
+#endif
+CND(NI_NOFQDN, "Return only the hostname part for local hosts")
+
+#ifndef NI_NUMERICSERV
+# define NI_NUMERICSERV -1
+#endif
+CND(NI_NUMERICSERV, "Numeric form of the service")
+
+#ifndef NI_NUMERICHOST
+# define NI_NUMERICHOST -1
+#endif
+CND(NI_NUMERICHOST, "Numeric form of the hostname")
+
+#ifndef NI_MAXHOST
+# define NI_MAXHOST -1
+#endif
+CND(NI_MAXHOST, "Maximum size of hostname")
+
+#ifndef NI_MAXSERV
+# define NI_MAXSERV -1
+#endif
+CND(NI_MAXSERV, "Maximum size of service name")
+
+#ifndef EAI_SYSTEM
+# define EAI_SYSTEM -1
+#endif
+CND(EAI_SYSTEM, "Check errno for details")
+
 /*
 
    ------------------
@@ -1074,6 +1206,11 @@ CND(SOCK_STREAM, "Stream socket")
 #endif
 CND(SOCK_DGRAM, "Datagram socket")
 
+#ifndef SOCK_RAW
+# define SOCK_RAW -1
+#endif
+CND(SOCK_RAW, "Raw socket")
+
 /*
 
    -----------------
@@ -1143,6 +1280,11 @@ CND(SOL_SOCKET, "Options for socket level")
 #endif
 CND(IPPROTO_IP, "Dummy protocol for IP")
 
+#ifndef IPPROTO_IPV6
+# define IPPROTO_IPV6 -1
+#endif
+CND(IPPROTO_IPV6, "IPv6 socket option level")
+
 #ifndef IPPROTO_UDP
 # define IPPROTO_UDP -1
 #endif
@@ -1300,6 +1442,111 @@ CND(IP_DROP_MEMBERSHIP, "Leave a multicast group")
 #endif
 CND(IP_PKTINFO, "Get datagram info")
 
+#ifndef IP_RECVERR
+# define IP_RECVERR -1
+#endif
+CND(IP_RECVERR, "Extended reliable error message passing")
+
+#ifndef IPV6_ADDRFORM
+# define IPV6_ADDRFORM -1
+#endif
+CND(IPV6_ADDRFORM, "Turn IPv6 socket into different address family")
+
+#ifndef IPV6_ADD_MEMBERSHIP
+# define IPV6_ADD_MEMBERSHIP -1
+#endif
+CND(IPV6_ADD_MEMBERSHIP, "Join IPv6 multicast group")
+
+#ifndef IPV6_DROP_MEMBERSHIP
+# define IPV6_DROP_MEMBERSHIP -1
+#endif
+CND(IPV6_DROP_MEMBERSHIP, "Leave IPv6 multicast group")
+
+#ifndef IPV6_MTU
+# define IPV6_MTU -1
+#endif
+CND(IPV6_MTU, "Set/get MTU used for the socket")
+
+#ifndef IPV6_MTU_DISCOVER
+# define IPV6_MTU_DISCOVER -1
+#endif
+CND(IPV6_MTU_DISCOVER, "Control path-MTU discovery on the socket")
+
+#ifndef IPV6_MULTICAST_HOPS
+# define IPV6_MULTICAST_HOPS -1
+#endif
+CND(IPV6_MULTICAST_HOPS, "Set the multicast hop limit for the socket")
+
+#ifndef IPV6_MULTICAST_IF
+# define IPV6_MULTICAST_IF -1
+#endif
+CND(IPV6_MULTICAST_IF, "Set/get IPv6 mcast interface")
+
+#ifndef IPV6_MULTICAST_LOOP
+# define IPV6_MULTICAST_LOOP -1
+#endif
+CND(IPV6_MULTICAST_LOOP, "Set/get mcast loopback")
+
+#ifndef IPV6_RECVPKTINFO
+# define IPV6_RECVPKTINFO -1
+#endif
+CND(IPV6_RECVPKTINFO, "Set delivery of the IPV6_PKTINFO")
+
+#ifndef IPV6_PKTINFO
+# define IPV6_PKTINFO -1
+#endif
+CND(IPV6_PKTINFO, "Get IPv6datagram info")
+
+#ifndef IPV6_RTHDR
+# define IPV6_RTHDR -1
+#endif
+CND(IPV6_RTHDR, "Set the routing header delivery")
+
+#ifndef IPV6_AUTHHDR
+# define IPV6_AUTHHDR -1
+#endif
+CND(IPV6_AUTHHDR, "Set the authentication header delivery")
+
+#ifndef IPV6_DSTOPTS
+# define IPV6_DSTOPTS -1
+#endif
+CND(IPV6_DSTOPTS, "Set the destination options delivery")
+
+#ifndef IPV6_HOPOPTS
+# define IPV6_HOPOPTS -1
+#endif
+CND(IPV6_HOPOPTS, "Set the hop options delivery")
+
+#ifndef IPV6_FLOWINFO
+# define IPV6_FLOWINFO -1
+#endif
+CND(IPV6_FLOWINFO, "Set the flow ID delivery")
+
+#ifndef IPV6_HOPLIMIT
+# define IPV6_HOPLIMIT -1
+#endif
+CND(IPV6_HOPLIMIT, "Set the hop count of the packet delivery")
+
+#ifndef IPV6_RECVERR
+# define IPV6_RECVERR -1
+#endif
+CND(IPV6_RECVERR, "Extended reliable error message passing")
+
+#ifndef IPV6_ROUTER_ALERT
+# define IPV6_ROUTER_ALERT -1
+#endif
+CND(IPV6_ROUTER_ALERT, "Pass forwarded router alert hop-by-hop option")
+
+#ifndef IPV6_UNICAST_HOPS
+# define IPV6_UNICAST_HOPS -1
+#endif
+CND(IPV6_UNICAST_HOPS, "Set the unicast hop limit")
+
+#ifndef IPV6_V6ONLY
+# define IPV6_V6ONLY -1
+#endif
+CND(IPV6_V6ONLY, "Restricted to IPv6 communications only")
+
 /*
 
    ----------------------
@@ -1367,6 +1614,22 @@ CND(SIZEOF_struct_servent, "struct servent")
 CND(SIZEOF_sigset, "sigset")
 #endif
 
+#if defined(_WIN32) || defined(__vxworks)
+#define SIZEOF_socklen_t sizeof (size_t)
+#else
+#define SIZEOF_socklen_t sizeof (socklen_t)
+#endif
+CND(SIZEOF_socklen_t, "Size of socklen_t");
+
+#ifndef IF_NAMESIZE
+#ifdef IF_MAX_STRING_SIZE
+#define IF_NAMESIZE IF_MAX_STRING_SIZE
+#else
+#define IF_NAMESIZE -1
+#endif
+#endif
+CND(IF_NAMESIZE, "Max size of interface name with 0 terminator");
+
 /*
 
    --  Fields of struct msghdr
@@ -1409,6 +1672,13 @@ C("Thread_Blocking_IO", Boolean, "True", "")
 #endif
 CST(Inet_Pton_Linkname, "")
 
+#ifdef HAVE_INET_NTOP
+# define Inet_Ntop_Linkname "inet_ntop"
+#else
+# define Inet_Ntop_Linkname "__gnat_inet_ntop"
+#endif
+CST(Inet_Ntop_Linkname, "")
+
 #endif /* HAVE_SOCKETS */
 
 /*

gcc/ada/socket.c

@@ -90,10 +90,27 @@ extern int __gnat_hostent_h_addrtype (struct hostent *);
 extern int __gnat_hostent_h_length (struct hostent *);
 extern char * __gnat_hostent_h_addr (struct hostent *, int);
 
+extern int __gnat_getaddrinfo(
+  const char *node,
+  const char *service,
+  const struct addrinfo *hints,
+  struct addrinfo **res);
+int __gnat_getnameinfo(
+  const struct sockaddr *sa, socklen_t salen,
+  char *host, size_t hostlen,
+  char *serv, size_t servlen, int flags);
+extern void __gnat_freeaddrinfo(struct addrinfo *res);
+extern const char * __gnat_gai_strerror(int errcode);
+
 #ifndef HAVE_INET_PTON
 extern int  __gnat_inet_pton (int, const char *, void *);
 #endif
 
+#ifndef HAVE_INET_NTOP
+extern const char *
+__gnat_inet_ntop(int, const void *, char *, socklen_t);
+#endif
+
 /* Disable the sending of SIGPIPE for writes on a broken stream */
 
 void
@@ -572,6 +589,41 @@ __gnat_inet_pton (int af, const char *src, void *dst) {
 }
 #endif
 
+#ifndef HAVE_INET_NTOP
+
+const char *
+__gnat_inet_ntop(int af, const void *src, char *dst, socklen_t size)
+{
+#ifdef _WIN32
+  struct sockaddr_storage ss;
+  int sslen = sizeof ss;
+  memset(&ss, 0, sslen);
+  ss.ss_family = af;
+
+  switch (af) {
+    case AF_INET6:
+      ((struct sockaddr_in6 *)&ss)->sin6_addr = *(struct in6_addr *)src;
+      break;
+    case AF_INET:
+      ((struct sockaddr_in *)&ss)->sin_addr = *(struct in_addr *)src;
+      break;
+    default:
+      errno = EAFNOSUPPORT;
+      return NULL;
+  }
+
+  DWORD sz = size;
+
+  if (WSAAddressToStringA((struct sockaddr*)&ss, sslen, 0, dst, &sz) != 0) {
+     return NULL;
+  }
+  return dst;
+#else
+  return NULL;
+#endif
+}
+#endif
+
 /*
  * Accessor functions for struct hostent.
  */
@@ -650,4 +702,105 @@ __gnat_servent_s_proto (struct servent * s)
   return s->s_proto;
 }
 
+#if defined(AF_INET6) && !defined(__rtems__)
+
+#if defined (__vxworks)
+#define getaddrinfo ipcom_getaddrinfo
+#define getnameinfo ipcom_getnameinfo
+#define freeaddrinfo ipcom_freeaddrinfo
+#endif
+
+int __gnat_getaddrinfo(
+  const char *node,
+  const char *service,
+  const struct addrinfo *hints,
+  struct addrinfo **res)
+{
+  return getaddrinfo(node, service, hints, res);
+}
+
+int __gnat_getnameinfo(
+  const struct sockaddr *sa, socklen_t salen,
+  char *host, size_t hostlen,
+  char *serv, size_t servlen, int flags)
+{
+  return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
+}
+
+void __gnat_freeaddrinfo(struct addrinfo *res) {
+   freeaddrinfo(res);
+}
+
+const char * __gnat_gai_strerror(int errcode) {
+#if defined(_WIN32) ||  defined(__vxworks)
+  // gai_strerror thread usafe on Windows and is not available on some vxWorks
+  // versions
+
+  switch (errcode) {
+    case EAI_AGAIN:
+      return "Temporary failure in name resolution.";
+    case EAI_BADFLAGS:
+      return "Invalid value for ai_flags.";
+    case EAI_FAIL:
+      return "Nonrecoverable failure in name resolution.";
+    case EAI_FAMILY:
+      return "The ai_family member is not supported.";
+    case EAI_MEMORY:
+      return "Memory allocation failure.";
+#ifdef EAI_NODATA
+    // Could be not defined under the vxWorks
+    case EAI_NODATA:
+      return "No address associated with nodename.";
+#endif
+#if EAI_NODATA != EAI_NONAME
+    /* with mingw64 runtime EAI_NODATA and EAI_NONAME have the same value.
+       This applies to both win32 and win64 */
+    case EAI_NONAME:
+      return "Neither nodename nor servname provided, or not known.";
+#endif
+    case EAI_SERVICE:
+      return "The servname parameter is not supported for ai_socktype.";
+    case EAI_SOCKTYPE:
+      return "The ai_socktype member is not supported.";
+#ifdef EAI_SYSTEM
+    // Could be not defined, at least on Windows
+    case EAI_SYSTEM:
+      return "System error returned in errno";
+#endif
+    default:
+      return "Unknown error.";
+    }
+#else
+   return gai_strerror(errcode);
+#endif
+}
+
+#else
+
+int __gnat_getaddrinfo(
+  const char *node,
+  const char *service,
+  const struct addrinfo *hints,
+  struct addrinfo **res)
+{
+  return -1;
+}
+
+int __gnat_getnameinfo(
+  const struct sockaddr *sa, socklen_t salen,
+  char *host, size_t hostlen,
+  char *serv, size_t servlen, int flags)
+{
+  return -1;
+}
+
+void __gnat_freeaddrinfo(struct addrinfo *res) {
+}
+
+const char * __gnat_gai_strerror(int errcode) {
+   return "getaddinfo functions family is not supported";
+}
+
+#endif
+
 #endif /* defined(HAVE_SOCKETS) */