[Byte™]

So I know how to create a bio and connect/perform a handshake right away using this plain method: (Simplified with no error checking)

SSL_CTX ctx = SSL_CTX_new(TLSv1_2_client_method());
SSL ssl;


BIO *bio = BIO_new_ssl_connect("ctx");
BIO_get_ssl(bio, &ssl);
SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY);

BIO_set_conn_hostname(bio, "smtp.gmail.com:465");
BIO_do_connect(bio);

But is there a way to create a connect with BIO_new_connect() and then perform a handshake later with the same bio that BIO_new_connect() made?

The reason I ask is because am creating a small email library for my self and the TLS SMTP server from gmail requires you to connect insecurely first, then send the STARTTLS command then perform the handshake. Problem is I don't know how to perform a handshake on non-insecure bio. I've been searching but it seems like the OpenSSL documentation is truly scattered and the information that is there is vague or not related to what I am looking for.

[Goodies]

Run an ltrace on the openssl utility connecting to your desired mail server. I chose live.com.

Code

ltrace -o openssl openssl s_client -connect smtp.live.com:25 -starttls smtp

Kinda large (Click to View)

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Just a starting point since I have little openssl experience.

[owonbo]

What are the programe detail.
I will like to practice it in class please.
im a student of computer programming year 1 in university of ireland