feat(tls): add ALPN support

compio-tls/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "compio-tls"
-version = "0.3.0"
+version = "0.3.1"
 description = "TLS adaptor with compio"
 categories = ["asynchronous", "network-programming"]
 keywords = ["async", "net", "tls"]
@@ -18,7 +18,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 compio-buf = { workspace = true }
 compio-io = { workspace = true, features = ["compat"] }
 
-native-tls = { version = "0.2.11", optional = true }
+native-tls = { version = "0.2.11", optional = true, features = ["alpn"] }
 rustls = { workspace = true, default-features = false, optional = true, features = [
     "logging",
     "std",

compio-tls/src/stream/mod.rs

@@ -1,4 +1,4 @@
-use std::{io, mem::MaybeUninit};
+use std::{borrow::Cow, io, mem::MaybeUninit};
 
 use compio_buf::{BufResult, IoBuf, IoBufMut};
 use compio_io::{compat::SyncStream, AsyncRead, AsyncWrite};
@@ -24,6 +24,15 @@ impl<S> TlsStreamInner<S> {
             Self::Rustls(s) => s.get_mut(),
         }
     }
+
+    pub fn negotiated_alpn(&self) -> Option<Cow<[u8]>> {
+        match self {
+            #[cfg(feature = "native-tls")]
+            Self::NativeTls(s) => s.negotiated_alpn().ok().flatten().map(Cow::from),
+            #[cfg(feature = "rustls")]
+            Self::Rustls(s) => s.negotiated_alpn().map(Cow::from),
+        }
+    }
 }
 
 impl<S> io::Read for TlsStreamInner<S> {
@@ -87,6 +96,11 @@ impl<S> TlsStream<S> {
     pub(crate) fn new_rustls_server(s: SyncStream<S>, conn: rustls::ServerConnection) -> Self {
         Self(TlsStreamInner::Rustls(rtls::TlsStream::new_server(s, conn)))
     }
+
+    /// Returns the negotiated ALPN protocol.
+    pub fn negotiated_alpn(&self) -> Option<Cow<[u8]>> {
+        self.0.negotiated_alpn()
+    }
 }
 
 #[cfg(feature = "native-tls")]

compio-tls/src/stream/rtls.rs

@@ -83,6 +83,13 @@ impl<S> TlsStream<S> {
     pub fn get_mut(&mut self) -> &mut S {
         &mut self.inner
     }
+
+    pub fn negotiated_alpn(&self) -> Option<&[u8]> {
+        match &self.conn {
+            TlsConnection::Client(client) => client.alpn_protocol(),
+            TlsConnection::Server(server) => server.alpn_protocol(),
+        }
+    }
 }
 
 impl<S: io::Read> TlsStream<S> {