Merge pull request #130: Transit improvements

Fancy things! And code cleanup.

- We now do firewall hole punching. If your device got a firewall connected (and it really should, and by default), direct transfers should now work for you too.
- If you aren't behind any NATs (IPv6 users rejoice), **direct connections should now work across the internet** 🎉
- NAT traversal using STUN, for our poor IPv4 users. Gives you direct connections as well, provided that the NAT behaves well (fortunately, they mostly do).
- If we found a connection over a relay, we wait some longer in the hope of a direct connection.

See also magic-wormhole/magic-wormhole-protocols#16 for some more words on what this code does in a bit more detail.

Cargo.toml

@@ -37,12 +37,17 @@ futures_ringbuf = "0.3.1"
 tar = "0.4.33"
 chrono = "0.4.19"
 
-derive_more = { version = "0.99.0", default-features = false, features = ["display", "deref"] }
+derive_more = { version = "0.99.0", default-features = false, features = ["display", "deref", "from"] }
 thiserror = "1.0.24"
 
 futures = "0.3.12"
 async-std = { version = "1.9.0", features = ["attributes", "unstable"] }
 async-tungstenite = { version = "0.14.0", features = ["async-std-runtime", "async-tls"] }
+async-io = "1.6.0"
+socket2 = "0.4.1"
+libc = "0.2.101"
+stun_codec = "0.1.13"
+bytecodec = "0.4.15"
 
 # for "bin" feature
 clap = { version = "2.33.3", optional = true }

src/core/key.rs

@@ -53,8 +53,8 @@ impl Key<WormholeKey> {
         let derived_key = self.derive_subkey_from_purpose(&transit_purpose);
         trace!(
             "Input key: {}, Transit key: {}, Transit purpose: '{}'",
-            hex::encode(&**self),
-            hex::encode(&**derived_key),
+            self.to_hex(),
+            derived_key.to_hex(),
             &transit_purpose
         );
         derived_key
@@ -65,6 +65,11 @@ impl<P: KeyPurpose> Key<P> {
     pub fn new(key: Box<secretbox::Key>) -> Self {
         Self(key, std::marker::PhantomData)
     }
+
+    pub fn to_hex(&self) -> String {
+        hex::encode(&**self)
+    }
+
     /**
      * Derive a new sub-key from this one
      */

src/core/test.rs

@@ -47,9 +47,7 @@ pub async fn test_file_rust2rust() -> eyre::Result<()> {
                     std::fs::metadata("examples/example-file.bin")
                         .unwrap()
                         .len(),
-                    |sent, total| {
-                        log::info!("Sent {} of {} bytes", sent, total);
-                    },
+                    |_sent, _total| {},
                 )
                 .await?,
             )
@@ -72,13 +70,7 @@ pub async fn test_file_rust2rust() -> eyre::Result<()> {
             .await?;
 
             let mut buffer = Vec::<u8>::new();
-            req.accept(
-                |received, total| {
-                    log::info!("Received {} of {} bytes", received, total);
-                },
-                &mut buffer,
-            )
-            .await?;
+            req.accept(|_received, _total| {}, &mut buffer).await?;
             Ok(buffer)
         })?;