From 0fdfcccec1a2e6cbd70ec47a57a255fbe1e285e0 Mon Sep 17 00:00:00 2001
From: Thomas Karpiniec <tom.karpiniec@outlook.com>
Date: Thu, 6 Jun 2024 21:14:17 +1000
Subject: [PATCH] Groundwork for watching iface changes on Apple via
 Network.framework

---
 Cargo.lock     | 32 ++++++++++++++++++++++++++++++++
 Cargo.toml     |  3 ++-
 src/imp_mac.rs | 27 +++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/Cargo.lock b/Cargo.lock
index 9af9c1b..632fe83 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -14,6 +14,15 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf4b9d6a944f767f8e5e0db018570623c85f3d925ac718db4e06d0187adb21c1"
 
+[[package]]
+name = "block2"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c132eebf10f5cad5289222520a4a058514204aed6d791f1cf4fe8088b82d15f"
+dependencies = [
+ "objc2",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -45,6 +54,7 @@ dependencies = [
 name = "netwatcher"
 version = "0.1.0"
 dependencies = [
+ "block2",
  "nix",
  "windows",
 ]
@@ -62,6 +72,28 @@ dependencies = [
  "memoffset",
 ]
 
+[[package]]
+name = "objc-sys"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb91bdd390c7ce1a8607f35f3ca7151b65afc0ff5ff3b34fa350f7d7c7e4310"
+
+[[package]]
+name = "objc2"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46a785d4eeff09c14c487497c162e92766fbb3e4059a71840cecc03d9a50b804"
+dependencies = [
+ "objc-sys",
+ "objc2-encode",
+]
+
+[[package]]
+name = "objc2-encode"
+version = "4.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7891e71393cd1f227313c9379a26a584ff3d7e6e7159e988851f0934c993f0f8"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.84"
diff --git a/Cargo.toml b/Cargo.toml
index 2615972..a1feb3c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,8 +5,9 @@ edition = "2021"
 
 [dependencies]
 
-[target.'cfg(unix)'.dependencies]
+[target.'cfg(target_vendor = "apple")'.dependencies]
 nix = { version = "0.29.0", features = ["net"] }
+block2 = "0.5.1"
 
 [target.'cfg(windows)'.dependencies.windows]
 version = "0.56.0"
diff --git a/src/imp_mac.rs b/src/imp_mac.rs
index c4fc8d6..4ae0fc7 100644
--- a/src/imp_mac.rs
+++ b/src/imp_mac.rs
@@ -1,5 +1,7 @@
 use std::{collections::HashMap, net::IpAddr};
 
+use block2::Block;
+use nix::libc::c_long;
 use nix::{ifaddrs::getifaddrs, net::if_::if_nametoindex};
 
 use crate::util::format_mac;
@@ -60,6 +62,31 @@ pub(crate) fn list_interfaces() -> Result<HashMap<IfIndex, Interface>, Error> {
     Ok(ifs)
 }
 
+// The "objc2" project aims to provide bindings for all frameworks but Network.framework
+// isn't ready yet so let's kick it old-school
+
+struct nw_path_monitor;
+type nw_path_monitor_t = *mut nw_path_monitor;
+struct nw_path;
+type nw_path_t = *mut nw_path;
+struct dispatch_queue;
+type dispatch_queue_t = *mut dispatch_queue;
+const QOS_CLASS_BACKGROUND: usize = 0x09;
+
+#[link(name = "Network", kind = "framework")]
+extern "C" {
+    fn nw_path_monitor_create() -> nw_path_monitor_t;
+    fn nw_path_monitor_set_update_handler(
+        monitor: nw_path_monitor_t,
+        update_handler: &Block<dyn Fn(nw_path_t)>,
+    );
+    fn nw_path_monitor_set_queue(monitor: nw_path_monitor_t, queue: dispatch_queue_t);
+    fn nw_path_monitor_start(monitor: nw_path_monitor_t);
+    fn nw_path_monitor_cancel(monitor: nw_path_monitor_t);
+
+    fn dispatch_get_global_queue(identifier: usize, flag: usize) -> dispatch_queue_t;
+}
+
 #[cfg(test)]
 mod test {
     use super::list_interfaces;
-- 
2.39.5