commit 3d41a5ff5559f07b163debf536a27ecbfc66f3b4
Author: Reynir Björnsson <reynir@reynir.dk>
Date:   Fri Sep 24 14:49:40 2021 +0200

    Initial commit

diff --git a/dune b/dune
new file mode 100644
index 0000000..5d92799
--- /dev/null
+++ b/dune
@@ -0,0 +1,3 @@
+(executable
+ (name udpdup)
+ (libraries lwt lwt.unix))
diff --git a/dune-project b/dune-project
new file mode 100644
index 0000000..c994249
--- /dev/null
+++ b/dune-project
@@ -0,0 +1 @@
+(lang dune 2.9)
diff --git a/udpdup.ml b/udpdup.ml
new file mode 100644
index 0000000..d0642c4
--- /dev/null
+++ b/udpdup.ml
@@ -0,0 +1,27 @@
+open Lwt.Infix
+
+let port = 2233
+
+let rec loop fd dests =
+  let recv_buf = Bytes.make 2048 '\000' in
+  Lwt_unix.recv fd recv_buf 0 (Bytes.length recv_buf) [] >>= fun read_len ->
+  Lwt_list.iter_p
+    (fun fd ->
+       Lwt_unix.send fd recv_buf 0 read_len [] >>= fun _send_len ->
+       Lwt.return_unit)
+    dests >>= fun () ->
+  loop fd dests
+
+let main () =
+  let addr = "0.0.0.0" in
+  let dests = ["127.0.0.1", 2234; "127.0.0.1", 2235] in
+  let fd = Lwt_unix.socket Lwt_unix.PF_INET Lwt_unix.SOCK_DGRAM 0 in
+  Lwt_unix.bind fd Unix.(ADDR_INET (inet_addr_of_string addr, port)) >>= fun () ->
+  Lwt_list.map_p (fun (addr, port) ->
+      let socket = Lwt_unix.socket Unix.PF_INET Unix.SOCK_DGRAM 0 in
+      Lwt_unix.connect socket Unix.(ADDR_INET (inet_addr_of_string addr, port)) >>= fun () ->
+      Lwt.return socket)
+    dests >>= fun dests ->
+  loop fd dests
+
+let () = Lwt_main.run (main ())