docs: Document Protocol struct

iroh-net/src/relay/client.rs

@@ -71,7 +71,7 @@ impl ClientReceiver {
 pub struct InnerClient {
     /// Our local address, if known.
     ///
-    /// `None` if we don't control the connection establishment, e.g. in browsers.
+    /// Is `None` in tests or when using websockets (because we don't control connection establishment in browsers).
     local_addr: Option<SocketAddr>,
     /// Channel on which to communicate to the server. The associated [`mpsc::Receiver`] will close
     /// if there is ever an error writing to the server.
@@ -126,6 +126,8 @@ impl Client {
     }
 
     /// The local address that the [`Client`] is listening on.
+    ///
+    /// `None`, when run in a testing environment or when using websockets.
     pub fn local_addr(&self) -> Option<SocketAddr> {
         self.inner.local_addr
     }

iroh-net/src/relay/http/server.rs

@@ -57,20 +57,29 @@ fn downcast_upgrade(upgraded: Upgraded) -> Result<(MaybeTlsStream, Bytes)> {
     }
 }
 
+/// The HTTP upgrade protocol used for relaying.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum Protocol {
+    /// Relays over the custom relaying protocol with a custom HTTP upgrade header
     Relay,
+    /// Relays over websockets
+    ///
+    /// Originally introduced to support browser connections.
     Websocket,
 }
 
 impl Protocol {
+    /// The HTTP upgrade header used or expected
     pub const fn upgrade_header(&self) -> &'static str {
         match self {
             Protocol::Relay => HTTP_UPGRADE_PROTOCOL,
             Protocol::Websocket => WEBSOCKET_UPGRADE_PROTOCOL,
         }
     }
 
+    /// Determines which protocol to use depending on a URL.
+    ///
+    /// `ws(s)` parses as websockets, `http(s)` parses to the custom relay protocol.
     pub fn from_url_scheme(url: &RelayUrl) -> Self {
         match url.scheme() {
             "ws" => Protocol::Websocket,
@@ -82,6 +91,7 @@ impl Protocol {
         }
     }
 
+    /// Tries to match the value of an HTTP upgrade header to figure out which protocol should be initiated.
     pub fn parse_header(header: &HeaderValue) -> Option<Self> {
         let header_bytes = header.as_bytes();
         if header_bytes == Protocol::Relay.upgrade_header().as_bytes() {