Espressif ESP32-S2 User Manual

Chapter 2. API Reference
Protocomm internally uses protobuf (protocol buffers) for secure session establishment. Though users can implement
their own security (even without using protobuf). One can even use protocomm without any security layer.
Protocomm provides framework for various transports - WiFi (SoftAP+HTTPD), BLE, console - in which case the
handler invocation is automatically taken care of on the device side (see Transport Examples below for code snippets).
Note that the client still needs to establish session (only for protocomm_security1) by performing the two way hand-
shake. See Unified Provisioning for more details about the secure handshake logic.
Transport Example (SoftAP + HTTP) with Security 1
For complete example see provisioning/legacy/softap_prov
/* Endpoint handler to be registered with protocomm.
* This simply echoes back the received data. */
esp_err_t echo_req_handler (uint32_t session_id,
const uint8_t *inbuf, ssize_t inlen,
uint8_t **outbuf, ssize_t *outlen,
void *priv_data)
{
/* Session ID may be used for persistence */
printf("Session ID : %d", session_id);
/* Echo back the received data */
*outlen = inlen; /* Output data length updated */
*outbuf = malloc(inlen); /* This will be deallocated outside */
memcpy(*outbuf, inbuf, inlen);
/* Private data that was passed at the time of endpoint creation */
uint32_t *priv = (uint32_t *) priv_data;
if (priv) {
printf("Private data : %d", *priv);
}
return ESP_OK;
}
/* Example function for launching a protocomm instance over HTTP */
protocomm_t *start_pc(const char *pop_string)
{
protocomm_t *pc = protocomm_new();
/* Config for protocomm_httpd_start() */
protocomm_httpd_config_t pc_config = {
.data = {
.config = PROTOCOMM_HTTPD_DEFAULT_CONFIG()
}
};
/* Start protocomm server on top of HTTP */
protocomm_httpd_start(pc, &pc_config);
/* Create Proof of Possession object from pop_string. It must be valid
* throughout the scope of protocomm endpoint. This need not be␣
,→static,
* ie. could be dynamically allocated and freed at the time of␣
,→endpoint
* removal */
const static protocomm_security_pop_t pop_obj = {
.data = (const uint8_t *) strdup(pop_string),
.len = strlen(pop_string)
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Release v4.4

Espressif ESP32-S2 Specifications

General

Brand	Espressif
Model	ESP32-S2
Category	Single board computers
Language	English