If you want to reuse the stream instance, you need to manipulate SSL_Socket.native_handle() with openssl lib function. After ssl shutdown, use SSL_clear() before start a new ssl handshake.
please read(pay attention to warnings) link for detail
SSL_clear() resets the SSL object to allow for another connection. The reset operation however keeps several settings of the last sessions (some of these settings were made automatically during the last handshake)
.........
WARNINGS
SSL_clear() resets the SSL object to allow for another connection. The reset operation however keeps several settings of the last sessions (some of these settings were made automatically during the last handshake). It only makes sense for a new connection with the exact same peer that shares these settings, and may fail if that peer changes its settings between connections. Use the sequence SSL_get_session(3); SSL_new(3); SSL_set_session(3); SSL_free(3) instead to avoid such failures (or simply SSL_free(3); SSL_new(3) if session reuse is not desired).
In regard to ssl shutdown issue, link explain how boost asio ssl shutdown work.
In Boost.Asio, the shutdown() operation is considered complete upon error or if the party has sent and received a close_notify message.
If you look at boost.asio (1.68) source code boost\asio\ssl\detail\impl\engine.ipp, it shows how boost.asio do ssl shutdown and stream_truncated happens when there is data to be read or ssl shutdown expected from peer not received.
int engine::do_shutdown(void*, std::size_t)
{
int result = ::SSL_shutdown(ssl_);
if (result == 0)
result = ::SSL_shutdown(ssl_);
return result;
}
const boost::system::error_code& engine::map_error_code(
boost::system::error_code& ec) const
......
// If there's data yet to be read, it's an error.
if (BIO_wpending(ext_bio_))
{
ec = boost::asio::ssl::error::stream_truncated;
return ec;
}
......
// Otherwise, the peer should have negotiated a proper shutdown.
if ((::SSL_get_shutdown(ssl_) & SSL_RECEIVED_SHUTDOWN) == 0)
{
ec = boost::asio::ssl::error::stream_truncated;
}
}
Also you can see boost.asio ssl shutdown routine may call openssl SSL_shutdown() twice if first return 0, openssl document allows it but advice call SSL_read() to do a bidirectional shutdown if first SSL_shutdown() returns 0.
Read link for details.
