[Ada] Add socket options to control keepalive on TCP connection

gcc/ada/

	* libgnat/g-socket.ads (Option_Name): Add Keep_Alive_Count,
	Keep_Alive_Idle, and Keep_Alive_Interval items to enumeration.
	(Option_Type): Add Keep_Alive_Count, Keep_Alive_Idle, and
	Keep_Alive_Interval alternatives to the case of discriminated
	record.
	* libgnat/g-socket.adb (Options): Add Keep_Alive_Count,
	Keep_Alive_Idle, and Keep_Alive_Interval to items enumerator to
	OS constant converter.
	(Set_Socket_Option): Process Keep_Alive_Count, Keep_Alive_Idle,
	and Keep_Alive_Interval socket options.
	(Get_Socket_Option): Idem.

2 files changed, 62 insertions, 14 deletions

diff --git a/gcc/ada/libgnat/g-socket.adb b/gcc/ada/libgnat/g-socket.adb
index ec4cf29..a246303 100644
--- a/gcc/ada/libgnat/g-socket.adb
+++ b/gcc/ada/libgnat/g-socket.adb
@@ -96,6 +96,9 @@ package body GNAT.Sockets is
 
    Options : constant array (Specific_Option_Name) of C.int :=
                (Keep_Alive          => SOSC.SO_KEEPALIVE,
+                Keep_Alive_Count    => SOSC.TCP_KEEPCNT,
+                Keep_Alive_Idle     => SOSC.TCP_KEEPIDLE,
+                Keep_Alive_Interval => SOSC.TCP_KEEPINTVL,
                 Reuse_Address       => SOSC.SO_REUSEADDR,
                 Broadcast           => SOSC.SO_BROADCAST,
                 Send_Buffer         => SOSC.SO_SNDBUF,
@@ -1442,6 +1445,9 @@ package body GNAT.Sockets is
             | Error
             | Generic_Option
             | Keep_Alive
+            | Keep_Alive_Count
+            | Keep_Alive_Idle
+            | Keep_Alive_Interval
             | Multicast_If_V4
             | Multicast_If_V6
             | Multicast_Loop_V4
@@ -1511,6 +1517,15 @@ package body GNAT.Sockets is
          =>
             Opt.Enabled := (V4 /= 0);
 
+         when Keep_Alive_Count =>
+            Opt.Count := Natural (V4);
+
+         when Keep_Alive_Idle =>
+            Opt.Idle_Seconds := Natural (V4);
+
+         when Keep_Alive_Interval =>
+            Opt.Interval_Seconds := Natural (V4);
+
          when Busy_Polling =>
             Opt.Microseconds := Natural (V4);
 
@@ -2620,6 +2635,21 @@ package body GNAT.Sockets is
             Len := V4'Size / 8;
             Add := V4'Address;
 
+         when Keep_Alive_Count =>
+            V4  := C.int (Option.Count);
+            Len := V4'Size / 8;
+            Add := V4'Address;
+
+         when Keep_Alive_Idle =>
+            V4  := C.int (Option.Idle_Seconds);
+            Len := V4'Size / 8;
+            Add := V4'Address;
+
+         when Keep_Alive_Interval =>
+            V4  := C.int (Option.Interval_Seconds);
+            Len := V4'Size / 8;
+            Add := V4'Address;
+
          when Busy_Polling =>
             V4  := C.int (Option.Microseconds);
             Len := V4'Size / 8;
diff --git a/gcc/ada/libgnat/g-socket.ads b/gcc/ada/libgnat/g-socket.ads
index 03afd36..4372f3e 100644
--- a/gcc/ada/libgnat/g-socket.ads
+++ b/gcc/ada/libgnat/g-socket.ads
@@ -845,11 +845,20 @@ package GNAT.Sockets is
       -- IP_Protocol_For_TCP_Level --
       -------------------------------
 
-      No_Delay, -- TCP_NODELAY
+      No_Delay,            -- TCP_NODELAY
       --  Disable the Nagle algorithm. This means that output buffer content
       --  is always sent as soon as possible, even if there is only a small
       --  amount of data.
 
+      Keep_Alive_Count,    -- TCP_KEEPCNT
+      --  Maximum number of keepalive probes
+
+      Keep_Alive_Idle,     -- TCP_KEEPIDLE
+      --  Idle time before TCP starts sending keepalive probes
+
+      Keep_Alive_Interval, -- TCP_KEEPINTVL
+      --  Time between individual keepalive probes
+
       ------------------------------
       -- IP_Protocol_For_IP_Level --
       ------------------------------
@@ -923,26 +932,35 @@ package GNAT.Sockets is
             Enabled : Boolean;
 
             case Name is
-               when Linger    =>
+               when Linger =>
                   Seconds : Natural;
-               when others    =>
+               when others =>
                   null;
             end case;
 
-         when Busy_Polling    =>
+         when Keep_Alive_Count    =>
+            Count : Natural;
+
+         when Keep_Alive_Idle     =>
+            Idle_Seconds : Natural;
+
+         when Keep_Alive_Interval =>
+            Interval_Seconds : Natural;
+
+         when Busy_Polling        =>
             Microseconds : Natural;
 
-         when Send_Buffer     |
-              Receive_Buffer  =>
+         when Send_Buffer         |
+              Receive_Buffer      =>
             Size : Natural;
 
-         when Error           =>
+         when Error               =>
             Error : Error_Type;
 
-         when Add_Membership_V4  |
-              Add_Membership_V6  |
-              Drop_Membership_V4 |
-              Drop_Membership_V6 =>
+         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  |
@@ -958,13 +976,13 @@ package GNAT.Sockets is
          when Multicast_If_V6 =>
             Outgoing_If_Index : Natural;
 
-         when Multicast_TTL  =>
+         when Multicast_TTL   =>
             Time_To_Live : Natural;
 
-         when Multicast_Hops =>
+         when Multicast_Hops  =>
             Hop_Limit : Integer range -1 .. 255;
 
-         when Send_Timeout |
+         when Send_Timeout    |
               Receive_Timeout =>
             Timeout : Timeval_Duration;