Allow Diplonat to automatically detect it's private IP

1 files changed, 33 insertions, 5 deletions

diff --git a/src/igd_actor.rs b/src/igd_actor.rs
index bb9099e..d32f5dc 100644
--- a/src/igd_actor.rs
+++ b/src/igd_actor.rs
@@ -22,7 +22,7 @@ pub struct IgdActor {
 
 impl IgdActor {
   pub async fn new(
-    priv_ip: &str,
+    priv_ip: Option<&str>,
     refresh: Duration,
     expire: Duration,
     rxp: &watch::Receiver<messages::PublicExposedPorts>,
@@ -32,16 +32,44 @@ impl IgdActor {
       .context("Failed to find IGD gateway")?;
     info!("IGD gateway: {}", gw);
 
+    let private_ip = if let Some(ip) = priv_ip {
+      info!("Using private IP from config: {}", ip);
+      ip.to_string()
+    } else {
+      info!("Trying to automatically detect private IP");
+      let gwa = gw.addr.ip().octets();
+      let cmplen = match gwa {
+        [192, 168, _, _] => 3,
+        [10, _, _, _] => 2,
+        _ => panic!(
+          "Gateway IP does not appear to be in a local network ({})",
+          gw.addr.ip()
+        ),
+      };
+      let public_ip = get_if_addrs::get_if_addrs()?
+        .into_iter()
+        .map(|i| i.addr.ip())
+        .filter(|a| match a {
+          std::net::IpAddr::V4(a4) => (a4.octets()[..cmplen] == gwa[..cmplen]),
+          _ => false,
+        })
+        .next()
+        .expect("No interface has an IP on same subnet as gateway")
+        .to_string();
+      info!("Found private IP: {}", public_ip);
+      public_ip
+    };
+
     let ctx = Self {
       gateway: gw,
       rx_ports: rxp.clone(),
-      private_ip: priv_ip.to_string(),
+      private_ip,
       refresh: refresh,
       expire: expire,
       last_ports: messages::PublicExposedPorts::new(),
     };
 
-    return Ok(ctx)
+    return Ok(ctx);
   }
 
   pub async fn listen(&mut self) -> Result<()> {
@@ -49,7 +77,7 @@ impl IgdActor {
     loop {
       // 1. Wait for an event
       let new_ports = select! {
-        Some(ports) = self.rx_ports.recv() => Some(ports),
+        _ = self.rx_ports.changed() => Some(self.rx_ports.borrow().clone()),
         _ = interval.tick() => None,
         else => return Ok(()) // Sender dropped, terminate loop.
       };
@@ -93,6 +121,6 @@ impl IgdActor {
       }
     }
 
-    return Ok(())
+    return Ok(());
   }
 }