Use sudo ifconfig instead of libc to set mtu

Author: Sebastian Holmin

test/test-manager/src/tests/tunnel_state.rs

@@ -32,18 +32,32 @@ use test_rpc::ServiceClient;
 fn set_bridge_interface_mtu(
     max_packet_size: u16,
 ) -> anyhow::Result<scopeguard::ScopeGuard<(), impl FnOnce(())>> {
-    use anyhow::Context;
+    use anyhow::{bail, Context};
     use test_rpc::net::unix;
     let bridge_iface: String = crate::vm::network::macos::find_vm_bridge()
         .context("Failed to get bridge interface name")?;
 
     let previous_mtu = unix::get_mtu(&bridge_iface)
         .with_context(|| format!("Failed to get MTU for bridge interface '{bridge_iface}'"))?;
-    unix::set_mtu(&bridge_iface, max_packet_size)
+
+    let set_mtu_fn = move |mtu: u16, interface: &str| {
+        let mut cmd = std::process::Command::new("/usr/bin/sudo");
+        cmd.args(["/usr/sbin/ifconfig", interface, "mtu", &format!("{mtu}")]);
+        let output = cmd.output().context("Failed to execute ifconfig")?;
+        if !output.status.success() {
+            bail!(
+                "ifconfig failed with status: {}",
+                output.status.code().unwrap()
+            );
+        }
+        Ok(())
+    };
+    set_mtu_fn(max_packet_size, &bridge_iface)
         .with_context(|| format!("Failed to set MTU for bridge interface '{bridge_iface}'"))?;
 
     Ok(scopeguard::guard((), move |()| {
-        unix::set_mtu(&bridge_iface, previous_mtu).expect("Failed to set MTU on bridge interface");
+        set_mtu_fn(previous_mtu, &bridge_iface)
+            .unwrap_or_else(|_| panic!("Failed to set MTU for bridge interface '{bridge_iface}'"));
     }))
 }