From 804a18bb9265b65ed01ea345a1ce440ff450b37f Mon Sep 17 00:00:00 2001
From: Anil Madhavapeddy <anil@recoil.org>
Date: Sat, 22 Jul 2023 15:58:50 +0100
Subject: [PATCH] add TCP_DEFER_ACCEPT and TCP_NO_DELAY socket options

---
 lib_eio/unix/net.ml    |  8 ++++++++
 lib_eio/unix/net.mli   |  2 ++
 lib_eio/unix/sockopt.c | 12 +++++++++++-
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lib_eio/unix/net.ml b/lib_eio/unix/net.ml
index ccaa52fc0..dd29fd508 100644
--- a/lib_eio/unix/net.ml
+++ b/lib_eio/unix/net.ml
@@ -53,6 +53,8 @@ type socket_int_option =
   | EIO_TCP_KEEPCNT
   | EIO_TCP_KEEPIDLE
   | EIO_TCP_KEEPINTVL
+  | EIO_TCP_DEFER_ACCEPT
+  | EIO_TCP_NODELAY
 
 external setsockopt_int : Unix.file_descr -> socket_int_option -> int -> unit =
   "eio_unix_setsockopt_int"
@@ -64,10 +66,12 @@ module Sockopt = struct
   | SO_KEEPALIVE : bool Eio.Net.Sockopt.t
   | SO_REUSEADDR : bool Eio.Net.Sockopt.t
   | SO_REUSEPORT : bool Eio.Net.Sockopt.t
+  | TCP_NODELAY : bool Eio.Net.Sockopt.t
   | TCP_CORK : int Eio.Net.Sockopt.t
   | TCP_KEEPCNT : int Eio.Net.Sockopt.t
   | TCP_KEEPIDLE : int Eio.Net.Sockopt.t
   | TCP_KEEPINTVL : int Eio.Net.Sockopt.t
+  | TCP_DEFER_ACCEPT : int Eio.Net.Sockopt.t
 
   let set : type a . Fd.t -> a Eio.Net.Sockopt.t -> a -> unit = fun sock k v ->
     Fd.use_exn "Sockopt.set" sock @@ fun fd ->
@@ -76,6 +80,8 @@ module Sockopt = struct
     | 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
+    | TCP_DEFER_ACCEPT -> setsockopt_int fd EIO_TCP_DEFER_ACCEPT v
+    | TCP_NODELAY -> setsockopt_int fd EIO_TCP_DEFER_ACCEPT (if v then 1 else 0)
     | SO_KEEPALIVE -> Unix.(setsockopt fd SO_KEEPALIVE v)
     | SO_REUSEADDR -> Unix.(setsockopt fd SO_REUSEADDR v)
     | SO_REUSEPORT -> Unix.(setsockopt fd SO_REUSEPORT v)
@@ -87,6 +93,8 @@ module Sockopt = struct
     | TCP_KEEPCNT -> getsockopt_int fd EIO_TCP_KEEPCNT
     | TCP_KEEPIDLE -> getsockopt_int fd EIO_TCP_KEEPIDLE
     | TCP_KEEPINTVL -> getsockopt_int fd EIO_TCP_KEEPINTVL
+    | TCP_DEFER_ACCEPT -> getsockopt_int fd EIO_TCP_DEFER_ACCEPT
+    | TCP_NODELAY -> getsockopt_int fd EIO_TCP_NODELAY = 1
     | SO_KEEPALIVE -> Unix.(getsockopt fd SO_KEEPALIVE)
     | SO_REUSEADDR -> Unix.(getsockopt fd SO_REUSEADDR)
     | SO_REUSEPORT -> Unix.(getsockopt fd SO_REUSEPORT)
diff --git a/lib_eio/unix/net.mli b/lib_eio/unix/net.mli
index 08812d371..f286feb68 100644
--- a/lib_eio/unix/net.mli
+++ b/lib_eio/unix/net.mli
@@ -87,6 +87,8 @@ module Sockopt : sig
   | TCP_KEEPCNT : int Eio.Net.Sockopt.t
   | TCP_KEEPIDLE : int Eio.Net.Sockopt.t
   | TCP_KEEPINTVL : int Eio.Net.Sockopt.t
+  | TCP_DEFER_ACCEPT : int Eio.Net.Sockopt.t
+  | TCP_NODELAY : bool Eio.Net.Sockopt.t
 
   val set : Fd.t -> 'a Eio.Net.Sockopt.t -> 'a -> unit
   (** [set fd opt v] sets the [opt] option to value [v] on socket [fd]. *)
diff --git a/lib_eio/unix/sockopt.c b/lib_eio/unix/sockopt.c
index 323e9cccc..351222edc 100644
--- a/lib_eio/unix/sockopt.c
+++ b/lib_eio/unix/sockopt.c
@@ -27,6 +27,14 @@
 #define TCP_KEEPINTVL (-1)
 #endif
 
+#ifndef TCP_DEFER_ACCEPT
+#define TCP_DEFER_ACCEPT (-1)
+#endif
+
+#ifndef TCP_NODELAY
+#define TCP_NODELAY (-1)
+#endif
+
 struct socket_option {
   int level;
   int option;
@@ -40,7 +48,9 @@ static struct socket_option sockopt_int[] = {
   { IPPROTO_TCP, TCP_CORK },
   { IPPROTO_TCP, TCP_KEEPCNT },
   { IPPROTO_TCP, TCP_KEEPIDLE },
-  { IPPROTO_TCP, TCP_KEEPINTVL }
+  { IPPROTO_TCP, TCP_KEEPINTVL },
+  { IPPROTO_TCP, TCP_DEFER_ACCEPT },
+  { IPPROTO_TCP, TCP_NODELAY },
 };
 
 CAMLprim value eio_unix_getsockopt_int(value vsocket, value voption)