network: split out proxynat code

network/src/proxynat/mod.rs

@@ -0,0 +1,49 @@
+mod udp;
+
+use async_trait::async_trait;
+
+use log::{debug, warn};
+
+use tokio::sync::mpsc::channel;
+use tokio::sync::mpsc::Sender;
+
+use crate::proxynat::udp::ProxyUdpHandler;
+
+use crate::nat::{NatHandler, NatHandlerFactory, NatKey, NatKeyProtocol};
+
+pub struct ProxyNatHandlerFactory {}
+
+impl ProxyNatHandlerFactory {
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+
+#[async_trait]
+impl NatHandlerFactory for ProxyNatHandlerFactory {
+    async fn nat(&self, key: NatKey, sender: Sender<Vec<u8>>) -> Option<Box<dyn NatHandler>> {
+        debug!("creating proxy nat entry for key: {}", key);
+
+        match key.protocol {
+            NatKeyProtocol::Udp => {
+                let (rx_sender, rx_receiver) = channel::<Vec<u8>>(4);
+                let mut handler = ProxyUdpHandler::new(key, rx_sender);
+
+                if let Err(error) = handler.spawn(rx_receiver, sender.clone()).await {
+                    warn!("unable to spawn udp proxy handler: {}", error);
+                    None
+                } else {
+                    Some(Box::new(handler))
+                }
+            }
+
+            _ => None,
+        }
+    }
+}
+
+pub enum ProxyNatSelect {
+    External(usize),
+    Internal(Vec<u8>),
+    Closed,
+}