sockopt: implement setsockopt() for linux and luv backends

lib_eio/net.ml

@@ -260,3 +260,5 @@ let with_tcp_connect ?(timeout=Time.Timeout.none) ~host ~service t f =
       | `Unix _ -> None
     )
   |> aux
+
+let setsockopt (s:#socket) = s#setsockopt

lib_eio/net.mli

@@ -267,6 +267,12 @@ val getnameinfo : #t -> Sockaddr.t -> (string * string)
     registered domain name represented by [sockaddr]. [service] is the IANA specified textual name of the
     port specified in [sockaddr], e.g. 'ftp', 'http', 'https', etc. *)
 
+(** {2 Socket} *)
+
+val setsockopt : #socket -> 'a sockopt -> 'a -> unit
+(** [setsockopt s opt v] configures socket [s] with socket option and value [opt]
+    and [v] respectively. *)
+
 (** {2 Closing} *)
 val close : <close: unit; ..> -> unit
 (** [close t] marks the socket as closed. It can no longer be used after this. *)

lib_eio/unix/eio_unix.mli

@@ -103,3 +103,5 @@ module Ctf = Ctf_unix
 
 val getnameinfo : Eio.Net.Sockaddr.t -> (string * string)
 (** [getnameinfo sockaddr] returns domain name and service for [sockaddr]. *)
+
+val setsockopt : Unix.file_descr -> 'a Eio.Net.sockopt -> 'a -> unit

lib_eio_linux/eio_linux.ml

@@ -1031,8 +1031,14 @@ let fallback_copy src dst =
     done
   with End_of_file -> ()
 
+class socket sock = object
+  inherit Eio.Net.socket
+  method setsockopt = Eio_unix.setsockopt (FD.to_unix `Peek sock)
+end
+
 let udp_socket sock = object
-  inherit Eio.Net.datagram_socket
+  inherit socket sock
+  inherit! Eio.Net.datagram_socket
 
   method close = FD.close sock
 
@@ -1053,15 +1059,17 @@ let udp_socket sock = object
         raise (Failure "Expected INET UDP socket address but got Unix domain socket address.")
 end
 
-let flow fd =
+class flow fd =
   let is_tty = lazy (Unix.isatty (FD.get_exn "isatty" fd)) in
-  object (_ : <source; sink; ..>)
+  object
+  inherit Eio.Flow.two_way
+
     method fd = fd
     method close = FD.close fd
 
     method stat = FD.fstat fd
 
-    method probe : type a. a Eio.Generic.ty -> a option = function
+    method! probe : type a. a Eio.Generic.ty -> a option = function
       | FD -> Some fd
       | Eio_unix.Private.Unix_file_descr op -> Some (FD.to_unix op fd)
       | _ -> None
@@ -1080,9 +1088,7 @@ let flow fd =
     method pwrite ~file_offset bufs =
       Low_level.writev_single ~file_offset fd bufs
 
-    method read_methods = []
-
-    method write bufs = Low_level.writev fd bufs
+    method! write bufs = Low_level.writev fd bufs
 
     method copy src =
       match get_fd_opt src with
@@ -1101,14 +1107,22 @@ let flow fd =
       | `Send -> Unix.SHUTDOWN_SEND
       | `All -> Unix.SHUTDOWN_ALL
 
-    method unix_fd op = FD.to_unix op fd
-  end
+    method unix_fd (op: [`Peek | `Take]) = FD.to_unix op fd
+end
+
+let flow fd = new flow fd
+
+let stream_socket fd = object(_ : <Eio.Net.stream_socket; ..>)
+  inherit socket fd
+  inherit! flow fd
+end
 
 let source fd = (flow fd :> source)
 let sink   fd = (flow fd :> sink)
 
 let listening_socket fd = object
-  inherit Eio.Net.listening_socket
+  inherit socket fd
+  inherit! Eio.Net.listening_socket
 
   method! probe : type a. a Eio.Generic.ty -> a option = function
     | Eio_unix.Private.Unix_file_descr op -> Some (FD.to_unix op fd)
@@ -1123,8 +1137,8 @@ let listening_socket fd = object
       | Unix.ADDR_UNIX path         -> `Unix path
       | Unix.ADDR_INET (host, port) -> `Tcp (Eio_unix.Ipaddr.of_unix host, port)
     in
-    let flow = (flow client :> <Eio.Flow.two_way; Eio.Flow.close>) in
-    flow, client_addr
+    let stream_socket = (stream_socket client :> <Eio.Net.stream_socket; Eio.Flow.close>) in
+    stream_socket, client_addr
 end
 
 let socket_domain_of = function
@@ -1183,7 +1197,7 @@ let net = object
     let sock_unix = Unix.socket (socket_domain_of connect_addr) socket_type 0 in
     let sock = FD.of_unix ~sw ~seekable:false ~close_unix:true sock_unix in
     Low_level.connect sock addr;
-    (flow sock :> <Eio.Flow.two_way; Eio.Flow.close>)
+    (stream_socket sock :> <Eio.Net.stream_socket; Eio.Flow.close>)
 
   method datagram_socket ~reuse_addr ~reuse_port ~sw saddr =
     let sock_unix = Unix.socket ~cloexec:true (socket_domain_of saddr) Unix.SOCK_DGRAM 0 in

lib_eio_luv/eio_luv.ml

@@ -674,8 +674,14 @@ end
 let source fd = (flow fd :> source)
 let sink   fd = (flow fd :> sink)
 
-let socket sock = object
-  inherit Eio.Flow.two_way as super
+class socket f sock = object
+  inherit Eio.Net.socket
+  method setsockopt = Eio_unix.setsockopt (f `Peek sock |> Option.get)
+end
+
+let stream_socket sock = object
+  inherit socket (Stream.to_unix_opt) sock
+  inherit! Eio.Net.stream_socket as super
 
   method! probe : type a. a Eio.Generic.ty -> a option = function
     | Eio_unix.Private.Unix_file_descr op -> Stream.to_unix_opt op sock
@@ -714,7 +720,8 @@ let socket sock = object
 end
 
 class virtual ['a] listening_socket ~backlog sock = object (self)
-  inherit Eio.Net.listening_socket as super
+  inherit socket Stream.to_unix_opt sock
+  inherit! Eio.Net.listening_socket as super
 
   method! probe : type a. a Eio.Generic.ty -> a option = function
     | Eio_unix.Private.Unix_file_descr op -> Stream.to_unix_opt op sock
@@ -736,7 +743,7 @@ class virtual ['a] listening_socket ~backlog sock = object (self)
       raise (Luv_error e)
     | Ok () ->
       Switch.on_release sw (fun () -> Handle.ensure_closed client);
-      let flow = (socket client :> <Eio.Flow.two_way; Eio.Flow.close>) in
+      let flow = (stream_socket client :> <Eio.Net.stream_socket; Eio.Flow.close>) in
       let client_addr = self#get_client_addr client in
       flow, client_addr
 
@@ -800,7 +807,8 @@ module Udp = struct
 end
 
 let udp_socket endp = object
-  inherit Eio.Net.datagram_socket
+  inherit socket Handle.to_unix_opt endp
+  inherit! Eio.Net.datagram_socket
 
   method close = Handle.close endp
 
@@ -865,10 +873,10 @@ let net = object
   method connect ~sw = function
     | `Tcp (host, port) ->
       let sock = Stream.connect_tcp ~sw (luv_addr_of_eio host port) in
-      (socket sock :> < Eio.Flow.two_way; Eio.Flow.close >)
+      (stream_socket sock :> < Eio.Net.stream_socket; Eio.Flow.close >)
     | `Unix path ->
       let sock = Stream.connect_pipe ~sw path in
-      (socket sock :> < Eio.Flow.two_way; Eio.Flow.close >)
+      (stream_socket sock :> < Eio.Net.stream_socket; Eio.Flow.close >)
 
   method datagram_socket ~reuse_addr ~reuse_port ~sw saddr =
     let domain = socket_domain_of saddr in
@@ -1178,7 +1186,7 @@ let rec run : type a. (_ -> a) -> a = fun main ->
               let sock = Luv.TCP.init ~loop () |> or_raise in
               let handle = Handle.of_luv ~sw ~close_unix sock in
               Luv.TCP.open_ sock fd |> or_raise;
-              continue k (socket handle :> Eio_unix.socket)
+              continue k (stream_socket handle :> Eio_unix.socket)
             with Luv_error _ as ex ->
               discontinue k ex
           )
@@ -1197,7 +1205,7 @@ let rec run : type a. (_ -> a) -> a = fun main ->
                 let sock = Luv.TCP.init ~loop () |> or_raise in
                 Luv.TCP.open_ sock x |> or_raise;
                 let h = Handle.of_luv ~sw ~close_unix:true sock in
-                (socket h :> Eio_unix.socket)
+                (stream_socket h :> Eio_unix.socket)
               in
               continue k (wrap a, wrap b)
             with Luv_error _ as ex ->