Add support set tls versions for RustlsConfig

crates/core/src/conn/rustls/config.rs

@@ -1,12 +1,13 @@
 //! rustls module
 use std::collections::HashMap;
 use std::fs::File;
-use std::future::{ready, Ready};
+use std::future::{Ready, ready};
 use std::io::{Error as IoError, Read, Result as IoResult};
 use std::path::Path;
 use std::sync::Arc;
 
-use futures_util::stream::{once, Once, Stream};
+use futures_util::stream::{Once, Stream, once};
+use tokio_rustls::rustls::SupportedProtocolVersion;
 use tokio_rustls::rustls::crypto::ring::sign::any_supported_type;
 use tokio_rustls::rustls::pki_types::{CertificateDer, PrivateKeyDer};
 use tokio_rustls::rustls::server::{ClientHello, ResolvesServerCert, WebPkiClientVerifier};
@@ -162,9 +163,10 @@ pub struct RustlsConfig {
     pub client_auth: TlsClientAuth,
     /// Protocols through ALPN (Application-Layer Protocol Negotiation).
     pub alpn_protocols: Vec<Vec<u8>>,
+    /// Supported TLS versions.
+    pub tls_versions: &'static [&'static SupportedProtocolVersion],
 }
 
-
 impl RustlsConfig {
     /// Create new `RustlsConfig`
     #[inline]
@@ -174,6 +176,7 @@ impl RustlsConfig {
             keycerts: HashMap::new(),
             client_auth: TlsClientAuth::Off,
             alpn_protocols: alpn_protocols(),
+            tls_versions: tokio_rustls::rustls::ALL_VERSIONS,
         }
     }
 
@@ -234,6 +237,16 @@ impl RustlsConfig {
         self
     }
 
+    /// Set specific TLS versions supported.
+    #[inline]
+    pub fn tls_versions(
+        mut self,
+        tls_versions: &'static [&'static SupportedProtocolVersion],
+    ) -> Self {
+        self.tls_versions = tls_versions;
+        self
+    }
+
     /// ServerConfig
     pub(crate) fn build_server_config(mut self) -> IoResult<ServerConfig> {
         let fallback = self
@@ -263,7 +276,7 @@ impl RustlsConfig {
             }
         };
 
-        let mut config = ServerConfig::builder()
+        let mut config = ServerConfig::builder_with_protocol_versions(self.tls_versions)
             .with_client_cert_verifier(client_auth)
             .with_cert_resolver(Arc::new(CertResolver {
                 certified_keys,