refactor/feat: add cert verifier call, cleanup and extend error enum

src/client/mod.rs

@@ -25,7 +25,7 @@ use tokio::{
     io::{AsyncBufReadExt, AsyncReadExt, AsyncWriteExt},
     net::TcpStream,
 };
-use tokio_rustls::TlsConnector;
+use tokio_rustls::{rustls, TlsConnector};
 use url::Url;
 
 pub struct Client {
@@ -101,6 +101,20 @@ impl Client {
         let stream = self.try_connect(host, port).await?;
         let mut stream = self.connector.connect(domain, stream).await?;
 
+        if let Some(ssv) = &self.ss_verifier {
+            let cert = stream
+                .get_ref()
+                .1 // rustls::ClientConnection
+                .peer_certificates()
+                .unwrap() // i think handshake already completed if we awaited on connector.connect?
+                .first()
+                .ok_or(rustls::Error::NoCertificatesPresented)?;
+
+            if !ssv.verify(cert, host, port).await? {
+                return Err(rustls::CertificateError::ApplicationVerificationFailure.into());
+            }
+        }
+
         // Write URL, then CRLF
         stream.write_all(url_str.as_bytes()).await?;
         stream.write_all(b"\r\n").await?;

src/error.rs

@@ -1,11 +1,11 @@
 //! Library error structures and enums
 
+use tokio_rustls::rustls;
+
 #[cfg(feature = "hickory")]
 use hickory_client::{
     error::ClientError as HickoryClientError, proto::error::ProtoError as HickoryProtoError,
 };
-#[cfg(feature = "hickory")]
-use tokio::runtime::TryCurrentError;
 
 /// Main error structure, also a wrapper for everything else
 #[derive(Debug)]
@@ -15,9 +15,12 @@ pub enum LibError {
     IoError(std::io::Error),
     /// URL parse or check error
     InvalidUrlError(InvalidUrl),
-    /// DNS provided no suitable records
+    /// DNS server has provided no suitable records
     /// (e. g. domain does not exist)
     HostLookupError,
+    /// TLS library error related to certificate/signature
+    /// verification failure or connection failure
+    RustlsError(rustls::Error),
     /// Response status code is out of [10; 69] range
     StatusOutOfRange(u8),
     /// Response metadata or content cannot be parsed
@@ -25,16 +28,9 @@ pub enum LibError {
     DataNotUtf8(std::string::FromUtf8Error),
     /// Provided string is not a valid MIME type
     InvalidMime(mime::FromStrError),
-    /// Hickory Client error
+    /// Hickory DNS client error
     #[cfg(feature = "hickory")]
     DnsClientError(HickoryClientError),
-    /// Hickory Proto error
-    #[cfg(feature = "hickory")]
-    DnsProtoError(HickoryProtoError),
-    /// Could not get Tokio runtime handle
-    /// inside Rustls cert verifier
-    #[cfg(feature = "hickory")]
-    NoTokioRuntime(TryCurrentError),
 }
 
 impl From<std::io::Error> for LibError {
@@ -58,6 +54,20 @@ impl From<InvalidUrl> for LibError {
     }
 }
 
+impl From<rustls::Error> for LibError {
+    #[inline]
+    fn from(err: rustls::Error) -> Self {
+        Self::RustlsError(err)
+    }
+}
+
+impl From<rustls::CertificateError> for LibError {
+    #[inline]
+    fn from(err: rustls::CertificateError) -> Self {
+        Self::RustlsError(err.into())
+    }
+}
+
 impl LibError {
     #[inline]
     pub fn status_out_of_range(num: u8) -> Self {
@@ -91,15 +101,7 @@ impl From<HickoryClientError> for LibError {
 impl From<HickoryProtoError> for LibError {
     #[inline]
     fn from(err: HickoryProtoError) -> Self {
-        Self::DnsProtoError(err)
-    }
-}
-
-#[cfg(feature = "hickory")]
-impl From<TryCurrentError> for LibError {
-    #[inline]
-    fn from(err: TryCurrentError) -> Self {
-        Self::NoTokioRuntime(err)
+        Self::DnsClientError(err.into())
     }
 }