* tls: negotiate until hs is complete in wolfSSL_read/wolfSSL_write
Don't rely on ssl->options.handShakeSate == HANDSHAKE_DONE to check if
negotiation is needed. wolfSSL_Connect() or wolfSSL_Accept() job may not yet be
completed and/or some messages may be waiting in the buffer because of
non-blocking I/O.
* tests: test case for handshake with wolfSSL_read()/wolfSSL_write()
* doc: clarify wolfSSL_write()
* internal.c: rename: need_negotiate -> ssl_in_handshake
This new function, wolfSSL_CTX_load_system_CA_certs, currently only supports
Linux-based OS's. It searches through conventional CA directories and once it
finds one, attempts to load CA certs from it. After the first directory is
found, we don't check the others.
This commit also adds a function wolfSSL_get_system_CA_dirs, which returns a
pointer to an array of directories where wolfSSL_CTX_load_system_CA_certs will
look for CA certs. This is used in a unit test, where we only want to expect
success if one of these directories actually exists on the test system.
Finally, this commit adds support for SSL_CTX_set_default_verify_paths to the
compatibility layer. It doesn't model the exact behavior of its OpenSSL
counterpart; it's mostly a wrapper around wolfSSL_CTX_load_system_CA_certs,
manipulating the return value of that function to conform to OpenSSL's
conventions.
Introduce ACK and retransmission logic, encapsulated in a Dtls13RtxFsm
object. The retransmission or the sending of an ACK is scheduled by setting the
appropriate flag inside the Dtls13RtxFSM object but the actual writing on the
socket is deferred and done in wolfSSL_Accept/Connect.
* Retransmission
Each sent message is encapsulated in a Dtl13RtxRecord and saved on a list. If we
receive an ACK for at record, we remove it from the list so it will be not
retransmitted further, then we will retransmit the remaining
ones. Retransmission is throttled: beside link congestion, this also avoid too
many sequence numbers bounded with a record.
* ACK
For each received record we save the record sequence number, so we can send an
ACK if needed. We send an ACK either if explicitly needed by the flight or if we
detect a disruption.
Co-authored-by: Juliusz Sosinowicz <juliusz@wolfssl.com>
Recommend using `wolfSSL_get1_session` and `NO_SESSION_CACHE_REF` for session resumption purposes. `wolfSSL_get_session` should not be used unless to inspect the current session object.