add Eio_unix.Sockopt for setting socket options

lib_eio/unix/dune

@@ -4,5 +4,5 @@
  (foreign_stubs
   (language c)
   (include_dirs include)
-  (names fork_action stubs))
+  (names sockopt fork_action stubs))
  (libraries eio unix threads mtime.clock.os))

lib_eio/unix/eio_unix.ml

@@ -3,6 +3,7 @@
 module Fd = Fd
 module Resource = Resource
 module Private = Private
+module Sockopt = Sockopt
 
 include Types
 type socket = Net.stream_socket

lib_eio/unix/eio_unix.mli

@@ -84,6 +84,20 @@ module Stdenv : sig
       You can use the functions in {!Eio.Stdenv} to access these fields if you prefer. *)
 end
 
+module Sockopt : sig
+  type 'a t = 'a Eio_unix__Sockopt.t =
+   | SO_KEEPALIVE : bool t
+   | SO_REUSEADDR : bool t
+   | SO_REUSEPORT : bool t
+   | TCP_CORK : int t
+   | TCP_KEEPCNT : int t
+   | TCP_KEEPIDLE : int t
+   | TCP_KEEPINTVL : int t
+
+  val set : Fd.t -> 'a t -> 'a -> unit
+  val get : Fd.t -> 'a t -> 'a
+end
+
 (** API for Eio backends only. *)
 module Private : sig
   type _ Effect.t += 

lib_eio/unix/sockopt.c

@@ -0,0 +1,65 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/socket.h>
+
+#ifdef __linux__
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#endif
+
+#include <caml/mlvalues.h>
+#include <caml/unixsupport.h>
+#include <caml/socketaddr.h>
+
+#ifndef TCP_CORK
+#define TCP_CORK (-1)
+#endif
+
+#ifndef TCP_KEEPCNT
+#define TCP_KEEPCNT (-1)
+#endif
+
+#ifndef TCP_KEEPIDLE
+#define TCP_KEEPIDLE (-1)
+#endif
+
+#ifndef TCP_KEEPINTVL
+#define TCP_KEEPINTVL (-1)
+#endif
+
+struct socket_option {
+  int level;
+  int option;
+};
+
+/* Not exported by caml/sockaddr.h */
+CAMLexport value caml_unix_getsockopt_aux(char *, int, int, int, value);
+CAMLexport value caml_unix_setsockopt_aux(char *, int, int, int, value, value);
+
+static struct socket_option sockopt_int[] = {
+  { IPPROTO_TCP, TCP_CORK },
+  { IPPROTO_TCP, TCP_KEEPCNT },
+  { IPPROTO_TCP, TCP_KEEPIDLE },
+  { IPPROTO_TCP, TCP_KEEPINTVL }
+};
+
+CAMLprim value eio_unix_getsockopt_int(value vsocket, value voption)
+{
+  struct socket_option *opt = &(sockopt_int[Int_val(voption)]);
+  return caml_unix_getsockopt_aux("eio_unix_getsockopt_int",
+                             1, /* TYPE_INT */
+                             opt->level,
+                             opt->option,
+                             vsocket);
+}
+
+CAMLprim value eio_unix_setsockopt_int(value vsocket, value voption, value val)
+{
+  struct socket_option *opt = &(sockopt_int[Int_val(voption)]);
+  return caml_unix_setsockopt_aux("eio_unix_setsockopt_int",
+                             1, /* TYPE_INT */
+                             opt->level,
+                             opt->option,
+                             vsocket,
+                             val);
+}

lib_eio/unix/sockopt.ml

@@ -0,0 +1,43 @@
+type socket_int_option =
+    EIO_TCP_CORK
+  | EIO_TCP_KEEPCNT
+  | EIO_TCP_KEEPIDLE
+  | EIO_TCP_KEEPINTVL
+
+external setsockopt_int : Unix.file_descr -> socket_int_option -> int -> unit =
+  "eio_unix_setsockopt_int"
+external getsockopt_int : Unix.file_descr -> socket_int_option -> int =
+  "eio_unix_getsockopt_int"
+
+type _ t =
+  | SO_KEEPALIVE : bool t
+  | SO_REUSEADDR : bool t
+  | SO_REUSEPORT : bool t
+  | TCP_CORK : int t
+  | TCP_KEEPCNT : int t
+  | TCP_KEEPIDLE : int t
+  | TCP_KEEPINTVL : int t
+
+let set : type a . Fd.t -> a t -> a -> unit = fun sock k v ->
+  Fd.use_exn "Sockaddr.set" sock @@ fun fd ->
+  match k with
+  | TCP_CORK -> setsockopt_int fd EIO_TCP_CORK v
+  | TCP_KEEPCNT -> setsockopt_int fd EIO_TCP_KEEPCNT v
+  | TCP_KEEPIDLE -> setsockopt_int fd EIO_TCP_KEEPIDLE v
+  | TCP_KEEPINTVL -> setsockopt_int fd EIO_TCP_KEEPINTVL v
+  | SO_KEEPALIVE -> Unix.(setsockopt fd SO_KEEPALIVE v)
+  | SO_REUSEADDR -> Unix.(setsockopt fd SO_REUSEADDR v)
+  | SO_REUSEPORT -> Unix.(setsockopt fd SO_REUSEPORT v)
+
+let get_descr : type a . Unix.file_descr -> a t -> a = fun fd k ->
+  match k with
+  | TCP_CORK -> getsockopt_int fd EIO_TCP_CORK
+  | TCP_KEEPCNT -> getsockopt_int fd EIO_TCP_KEEPCNT
+  | TCP_KEEPIDLE -> getsockopt_int fd EIO_TCP_KEEPIDLE
+  | TCP_KEEPINTVL -> getsockopt_int fd EIO_TCP_KEEPINTVL
+  | SO_KEEPALIVE -> Unix.(getsockopt fd SO_KEEPALIVE)
+  | SO_REUSEADDR -> Unix.(getsockopt fd SO_REUSEADDR)
+  | SO_REUSEPORT -> Unix.(getsockopt fd SO_REUSEPORT)
+
+let get : type a . Fd.t -> a t -> a = fun sock k ->
+  Fd.use_exn "Sockaddr.get" sock (fun fd -> get_descr fd k)

lib_eio/unix/sockopt.mli

@@ -0,0 +1,11 @@
+type _ t =
+ | SO_KEEPALIVE : bool t
+ | SO_REUSEADDR : bool t
+ | SO_REUSEPORT : bool t
+ | TCP_CORK : int t
+ | TCP_KEEPCNT : int t
+ | TCP_KEEPIDLE : int t
+ | TCP_KEEPINTVL : int t
+
+val set : Fd.t -> 'a t -> 'a -> unit
+val get : Fd.t -> 'a t -> 'a

lib_eio_posix/net.ml

@@ -97,11 +97,11 @@ let listen ~reuse_addr ~reuse_port ~backlog ~sw (listen_addr : Eio.Net.Sockaddr.
     | `Unix _ | `Tcp _ ->
       Switch.null_hook
   in
+  if reuse_addr then
+    Eio_unix.Sockopt.(set sock SO_REUSEADDR true);
+  if reuse_port then
+    Eio_unix.Sockopt.(set sock SO_REUSEPORT true);
   Fd.use_exn "listen" sock (fun fd ->
-      if reuse_addr then
-        Unix.setsockopt fd Unix.SO_REUSEADDR true;
-      if reuse_port then
-        Unix.setsockopt fd Unix.SO_REUSEPORT true;
       Unix.bind fd addr;
       Unix.listen fd backlog;
     );
@@ -126,13 +126,9 @@ let create_datagram_socket ~reuse_addr ~reuse_port ~sw saddr =
   begin match saddr with
     | `Udp _ | `Unix _ as saddr ->
       let addr = Eio_unix.Net.sockaddr_to_unix saddr in
-      Fd.use_exn "datagram_socket" sock (fun fd ->
-          if reuse_addr then
-            Unix.setsockopt fd Unix.SO_REUSEADDR true;
-          if reuse_port then
-            Unix.setsockopt fd Unix.SO_REUSEPORT true;
-          Unix.bind fd addr
-        )
+      if reuse_addr then Eio_unix.Sockopt.(set sock SO_REUSEADDR true);
+      if reuse_port then Eio_unix.Sockopt.(set sock SO_REUSEPORT true);
+      Fd.use_exn "datagram_socket" sock (fun fd -> Unix.bind fd addr)
     | `UdpV4 | `UdpV6 -> ()
   end;
   (datagram_socket sock :> Eio.Net.datagram_socket)