feat: set hostname for SNI

Set the hostname so that the server can use it to select the correct certificate (SNI).

1. add host parameter to TLSTransport function and set hostname SSLContext parameter
only if it was not provided as an IPV4 or IPV6 address

2. forward host from transport function call to  TLSTransport.

Author: billy34

src/transport/tls.jl

@@ -4,10 +4,16 @@ struct TLSTransport <: RedisTransport
     sslconfig::MbedTLS.SSLConfig
     buff::IOBuffer
 
-    function TLSTransport(sock::TCPSocket, sslconfig::MbedTLS.SSLConfig)
+    function TLSTransport(host::AbstractString, sock::TCPSocket, sslconfig::MbedTLS.SSLConfig)
         ctx = MbedTLS.SSLContext()
         MbedTLS.setup!(ctx, sslconfig)
         MbedTLS.associate!(ctx, sock)
+        # set hostname only if it's not an IP adress
+        try
+          parse(IPAddr, host)
+        catch x
+          MbedTLS.hostname!(ctx, host)
+        end
         MbedTLS.handshake(ctx)
 
         return new(sock, ctx, sslconfig, PipeBuffer())

src/transport/transport.jl

@@ -26,7 +26,7 @@ include("tcp.jl")
 
 function transport(host::AbstractString, port::Integer, sslconfig::Union{MbedTLS.SSLConfig, Nothing}=nothing)
     socket = connect(host, port)
-    return (sslconfig !== nothing) ? TLSTransport(socket, sslconfig) : TCPTransport(socket)
+    return (sslconfig !== nothing) ? TLSTransport(host, socket, sslconfig) : TCPTransport(socket)
 end
 
 end # module Transport