tls.h File Reference

Deterministic TLS engine: mbedTLS over a static memory pool (DETWS_ENABLE_TLS). More...

#include "ServerConfig.h"
#include <stddef.h>
#include <stdint.h>

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Detailed Description

Deterministic TLS engine: mbedTLS over a static memory pool (DETWS_ENABLE_TLS).

Wraps mbedTLS as a server-side TLS layer that keeps the library's zero-heap guarantee: mbedTLS is pointed at a fixed BSS arena via MBEDTLS_MEMORY_BUFFER_ALLOC_C (no system heap), per-connection ssl_context lives in BSS, the RNG is the ESP32 hardware CSPRNG, and the transport BIO is bridged directly to the existing lwIP tcp_pcb + per-connection rx ring - so there is no socket layer and no extra task. The handshake is pumped from the single handle() loop.

ESP32/Arduino only - mbedTLS is not part of the native build. The header compiles everywhere (the functions are no-op stubs unless DETWS_ENABLE_TLS and ARDUINO are both set) so call sites need no extra guards.

Lifecycle per connection:

det_tls_conn_begin(slot);                 // at accept on the TLS port
// each EvtType::EVT_DATA, until established:
int h = det_tls_handshake(slot);          // 1 done, 0 pending, <0 fatal
// once established, app data:
int n = det_tls_read(slot, buf, sizeof buf);   // >0 plaintext, 0 again, <0 closed
det_tls_write(slot, data, len);                // encrypts -> tcp_write
det_tls_conn_end(slot);                    // close_notify + free slot ctx

Definition in file tls.h.