fix bugs and improve user experiance (#86)

* correctly set mtu, and allow set mtu manually

* communicate between enc and non-enc should not panic

* allow loading cfg from file

* allow change file log level dynamically

easytier/src/peers/encrypt/aes_gcm.rs

@@ -38,7 +38,7 @@ impl Encryptor for AesGcmCipher {
     fn decrypt(&self, zc_packet: &mut ZCPacket) -> Result<(), Error> {
         let pm_header = zc_packet.peer_manager_header().unwrap();
         if !pm_header.is_encrypted() {
-            return Err(Error::NotEcrypted);
+            return Ok(());
         }
 
         let payload_len = zc_packet.payload().len();

easytier/src/peers/encrypt/mod.rs

@@ -8,8 +8,6 @@ pub mod aes_gcm;
 
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error("packet is not encrypted")]
-    NotEcrypted,
     #[error("packet is too short. len: {0}")]
     PacketTooShort(usize),
     #[error("decryption failed")]
@@ -32,7 +30,12 @@ impl Encryptor for NullCipher {
         Ok(())
     }
 
-    fn decrypt(&self, _zc_packet: &mut ZCPacket) -> Result<(), Error> {
-        Ok(())
+    fn decrypt(&self, zc_packet: &mut ZCPacket) -> Result<(), Error> {
+        let pm_header = zc_packet.peer_manager_header().unwrap();
+        if pm_header.is_encrypted() {
+            return Err(Error::DecryptionFailed);
+        } else {
+            Ok(())
+        }
     }
 }

easytier/src/peers/encrypt/ring_aes_gcm.rs

@@ -54,7 +54,7 @@ impl Encryptor for AesGcmCipher {
     fn decrypt(&self, zc_packet: &mut ZCPacket) -> Result<(), Error> {
         let pm_header = zc_packet.peer_manager_header().unwrap();
         if !pm_header.is_encrypted() {
-            return Err(Error::NotEcrypted);
+            return Ok(());
         }
 
         let payload_len = zc_packet.payload().len();