Add Unix.SO_REUSEPORT (#9869)

Support the SO_REUSEPORT socket option.

Closes: #3512

Changes

@@ -219,6 +219,9 @@ Working version
 - #9802: Ensure signals are handled before Unix.kill returns
   (Stephen Dolan, review by Jacques-Henri Jourdan)
 
+- #9869: Add Unix.SO_REUSEPORT
+  (Yishuai Li, review by Xavier Leroy)
+
 ### Tools:
 
 - #9551: ocamlobjinfo is now able to display information on .cmxs shared

otherlibs/unix/sockopt.c

@@ -38,6 +38,9 @@
 #ifndef SO_REUSEADDR
 #define SO_REUSEADDR (-1)
 #endif
+#ifndef SO_REUSEPORT
+#define SO_REUSEPORT (-1)
+#endif
 #ifndef SO_KEEPALIVE
 #define SO_KEEPALIVE (-1)
 #endif
@@ -109,6 +112,7 @@ static struct socket_option sockopt_bool[] = {
   { SOL_SOCKET, SO_DEBUG },
   { SOL_SOCKET, SO_BROADCAST },
   { SOL_SOCKET, SO_REUSEADDR },
+  { SOL_SOCKET, SO_REUSEPORT },
   { SOL_SOCKET, SO_KEEPALIVE },
   { SOL_SOCKET, SO_DONTROUTE },
   { SOL_SOCKET, SO_OOBINLINE },

otherlibs/unix/unix.ml

@@ -597,6 +597,7 @@ type socket_bool_option =
     SO_DEBUG
   | SO_BROADCAST
   | SO_REUSEADDR
+  | SO_REUSEPORT
   | SO_KEEPALIVE
   | SO_DONTROUTE
   | SO_OOBINLINE

otherlibs/unix/unix.mli

@@ -1429,6 +1429,7 @@ type socket_bool_option =
     SO_DEBUG       (** Record debugging information *)
   | SO_BROADCAST   (** Permit sending of broadcast messages *)
   | SO_REUSEADDR   (** Allow reuse of local addresses for bind *)
+  | SO_REUSEPORT   (** Allow reuse of address and port bindings *)
   | SO_KEEPALIVE   (** Keep connection active *)
   | SO_DONTROUTE   (** Bypass the standard routing algorithms *)
   | SO_OOBINLINE   (** Leave out-of-band data in line *)

otherlibs/unix/unixLabels.mli

@@ -1175,6 +1175,7 @@ type socket_bool_option =
     SO_DEBUG       (** Record debugging information *)
   | SO_BROADCAST   (** Permit sending of broadcast messages *)
   | SO_REUSEADDR   (** Allow reuse of local addresses for bind *)
+  | SO_REUSEPORT   (** Allow reuse of address and port bindings *)
   | SO_KEEPALIVE   (** Keep connection active *)
   | SO_DONTROUTE   (** Bypass the standard routing algorithms *)
   | SO_OOBINLINE   (** Leave out-of-band data in line *)

otherlibs/win32unix/sockopt.c

@@ -21,6 +21,9 @@
 #include "unixsupport.h"
 #include "socketaddr.h"
 
+#ifndef SO_REUSEPORT
+#define SO_REUSEPORT (-1)
+#endif
 #ifndef IPPROTO_IPV6
 #define IPPROTO_IPV6 (-1)
 #endif
@@ -47,6 +50,7 @@ static struct socket_option sockopt_bool[] = {
   { SOL_SOCKET, SO_DEBUG },
   { SOL_SOCKET, SO_BROADCAST },
   { SOL_SOCKET, SO_REUSEADDR },
+  { SOL_SOCKET, SO_REUSEPORT },
   { SOL_SOCKET, SO_KEEPALIVE },
   { SOL_SOCKET, SO_DONTROUTE },
   { SOL_SOCKET, SO_OOBINLINE },

otherlibs/win32unix/unix.ml

@@ -729,6 +729,7 @@ type socket_bool_option =
     SO_DEBUG
   | SO_BROADCAST
   | SO_REUSEADDR
+  | SO_REUSEPORT
   | SO_KEEPALIVE
   | SO_DONTROUTE
   | SO_OOBINLINE