The PR changes `run_allciphers()` to use `tls_sockets()` (and `sslv2_sockets()`)rather than `$OPENSSL` unless `$SSL_NATIVE` is set or `$STARTTLS` is non-empty. Using sockets allows `run_allciphers()` to test all ciphers, rather than just those supported by `$OPENSSL`.
Using sockets results in `run_allciphers()` running more slowly, partially since it is testing more ciphers, but mostly since `tls_sockets()` is currently slower than `$OPENSSL` (as noted in #413).
This PR makes similar changes to `run_client_simulation()` as were made to `tls_sockets()`, so that `run_client_simulation()` retrieves the entire server response, even if it is split across multiple packets, and it has `parse_tls_serverhello()` extract information about the server's ephemeral public key, if present.
The PR also changes `run_client_simulation()` to use information about the ephemeral public key. It includes the length of the public key in the output and, if it is a DH public key, checks that the size is within the acceptable range (`${minDhBits[i]} <= dh_bits <= ${maxDhBits[i]}`).
This PR adds initial parsing of the ServerKeyExchange message to `parse_tls_serverhello()`. For ephemeral DH keys, it extracts the length of the key. For ephemeral ECDH keys that are encoded using the named_curve option, it extracts the length of the key and the name of the curve.
This PR allows the caller to provide additional extensions to `tls_sockets()` to be included in the ClientHello. If the caller provides an extension that would have already been included in the ClientHello, then the caller's value for the extension is used rather than the default value.
This PR extended `parse_tls_serverhello()` in a few ways:
* If the "full" response is to be parsed, then additional checks are performed to verify that `$tls_hello_ascii` contains the entire response
* The extensions field is parsed and the list of extensions found is placed in `$TLS_EXTENSIONS` (if the "full" response is being parsed).
* Initial support for TLS 1.3 is added:
- Accounts for differences between TLS 1.2 ServerHello and TLS 1.3 ServerHello (as outlined in PR #499).
- Recognizes new alerts and handshake message types.
- Allows for server response to include message fragments of type "application data"
I forgot that `parse_tls_serverhello()` is also called by `client_simulation_sockets()`. Since PR #499 changed the input to `parse_tls_serverhello()`, the change needs to be made in `client_simulation_sockets()` as well.
