refactor(ext/tls): Implement required functionality for later SNI support (#23686)

Precursor to #23236 

This implements the SNI features, but uses private symbols to avoid
exposing the functionality at this time. Note that to properly test this
feature, we need to add a way for `connectTls` to specify a hostname.
This is something that should be pushed into that API at a later time as
well.

```ts
Deno.test(
  { permissions: { net: true, read: true } },
  async function listenResolver() {
    let sniRequests = [];
    const listener = Deno.listenTls({
      hostname: "localhost",
      port: 0,
      [resolverSymbol]: (sni: string) => {
        sniRequests.push(sni);
        return {
          cert,
          key,
        };
      },
    });

    {
      const conn = await Deno.connectTls({
        hostname: "localhost",
        [serverNameSymbol]: "server-1",
        port: listener.addr.port,
      });
      const [_handshake, serverConn] = await Promise.all([
        conn.handshake(),
        listener.accept(),
      ]);
      conn.close();
      serverConn.close();
    }

    {
      const conn = await Deno.connectTls({
        hostname: "localhost",
        [serverNameSymbol]: "server-2",
        port: listener.addr.port,
      });
      const [_handshake, serverConn] = await Promise.all([
        conn.handshake(),
        listener.accept(),
      ]);
      conn.close();
      serverConn.close();
    }

    assertEquals(sniRequests, ["server-1", "server-2"]);
    listener.close();
  },
);
```

---------

Signed-off-by: Matt Mastracci <matthew@mastracci.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/ext/kv/remote.rs b/ext/kv/remote.rs
index 88127fc8f..9d5e099c7 100644
--- a/ext/kv/remote.rs
+++ b/ext/kv/remote.rs
@@ -16,7 +16,7 @@ use deno_fetch::CreateHttpClientOptions;
 use deno_tls::rustls::RootCertStore;
 use deno_tls::Proxy;
 use deno_tls::RootCertStoreProvider;
-use deno_tls::TlsKey;
+use deno_tls::TlsKeys;
 use denokv_remote::MetadataEndpoint;
 use denokv_remote::Remote;
 use url::Url;
@@ -27,7 +27,7 @@ pub struct HttpOptions {
   pub root_cert_store_provider: Option<Arc<dyn RootCertStoreProvider>>,
   pub proxy: Option<Proxy>,
   pub unsafely_ignore_certificate_errors: Option<Vec<String>>,
-  pub client_cert_chain_and_key: Option<TlsKey>,
+  pub client_cert_chain_and_key: TlsKeys,
 }
 
 impl HttpOptions {
@@ -135,7 +135,11 @@ impl<P: RemoteDbHandlerPermissions + 'static> DatabaseHandler
         unsafely_ignore_certificate_errors: options
           .unsafely_ignore_certificate_errors
           .clone(),
-        client_cert_chain_and_key: options.client_cert_chain_and_key.clone(),
+        client_cert_chain_and_key: options
+          .client_cert_chain_and_key
+          .clone()
+          .try_into()
+          .unwrap(),
         pool_max_idle_per_host: None,
         pool_idle_timeout: None,
         http1: false,