Fixes for build and runtime issues

[embhorn]

Description

Fixes the following:

• Documentation for freeing fixed point ECC cache
• Free packet memory when WOLFSSL_CALLBACKS timeout CB is null
• Build error with HAVE_EX_DATA_CLEANUP_HOOKS and HAVE_EX_DATA not defined
• wolfSSL_BIO_clear_retry_flags to also clear the WOLFSSL_BIO_FLAG_WRITE flag
• fixed a build error in the example server when WOLFSSL_CALLBACKS and WOLFSSL_EARLY_DATA are defined

Fixes zd14659

Testing

commit checks

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[embhorn]

Fixes #5482

[maxammann]

The "Build error with HAVE_EX_DATA_CLEANUP_HOOKS and HAVE_EX_DATA not defined" was related to the usage of a wrong type called X509. This type does not exist in wolfSSL afaik, only WOLFSSL_X509 exists. Also function definitions above or after wolfSSL_X509_set_ex_data_with_cleanup use WOLFSSL_X509.

EDIT: Refering to the following line which seems odd: https://github.com/wolfSSL/wolfssl/blob/master/wolfssl/ssl.h#L4802

[maxammann]

Looks good for me except for the mentioned issue about the X509 type.

[maxammann]

I think it would be nice to notice this aswell in the manual. As a user of wolfSSL I would look for the "Thread Safety" section if I would implement a multi-threaded server: https://www.wolfssl.com/documentation/manuals/wolfssl/chapter09.html#thread-safety

[embhorn]

Great idea! I added this blurb to that section:

Some optimizations allocate memory on a per thread basis. If fixed point ECC cache is enabled (FP_ECC), then threads should release the cached buffers using wc_ecc_fp_free() before the thread exits.

[julek-wolfssl]

I'm not seeing this pushed to manual anywhere. Can you please check if you opened the PR to add this?

[embhorn]

The "Build error with HAVE_EX_DATA_CLEANUP_HOOKS and HAVE_EX_DATA not defined" was related to the usage of a wrong type called X509. This type does not exist in wolfSSL afaik, only WOLFSSL_X509 exists. Also function definitions above or after wolfSSL_X509_set_ex_data_with_cleanup use WOLFSSL_X509.

EDIT: Refering to the following line which seems odd: https://github.com/wolfSSL/wolfssl/blob/master/wolfssl/ssl.h#L4802

The compatibility layer headers map WOLFSSL_X509 to X509:

wolfssl/wolfssl/openssl/ssl.h

Line 81 in 969ad96

typedef WOLFSSL_X509 X509;

I've pushed a fix for the line you mentioned.

 WOLFSSL_API int wolfSSL_X509_set_ex_data_with_cleanup(
-    X509 *x509,
+    WOLFSSL_X509 *x509,

[kaleb-himes]

retest this please.