Problem:
1. In low-memory scenarios, the dynamic buffer feature can fail due to memory fragmentation.
2. It requires a contiguous 16KB heap chunk, but continuous allocation and deallocation of
the RX buffer can lead to fragmentation.
3. If another component allocates memory between these operations, it can break up the
available 16KB block, causing allocation failure.
Solution:
1. Introduce configurable strategy for using dynamic buffers in TLS connections.
2. For example, convert RX buffers to static after the TLS handshake.
3. Allow users to select the strategy via a new field in the esp_http_client_cfg_t structure.
4. The strategy can be controlled independently for each TLS session.
- Resulted in a crash in the handshake stage when
used alongside TLS 1.3 (MBEDTLS_SSL_PROTO_TLS1_3)
- Fix build error when MBEDTLS_HARDWARE_SHA=n &&
MBEDTLS_DYNAMIC_BUFFER=y
- Fix build error when TLS 1.3 is enabled with
MBEDTLS_SSL_KEEP_PEER_CERTIFICATE=n
- Removed code regarding MBEDTLS_DYNAMIC_FREE_PEER_CERT
(config was kept for backward compatibility)
- Combined mbedTLS v2.28.x related options under a separate Kconfig menu
RX process caches the session information in "ssl->in_ctr" not in "ssl->in_buf".
So when freeing the SSL, can't free the "ssl->in_ctr", because the "ssl->in_buf"
is empty.
Make the RX process like TX process, and cache the session information in
"ssl->in_buf", so that the cache buffer can be freed when freeing the SSL.
Closes https://github.com/espressif/esp-idf/issues/6104
