lwip_fast_select.h

Go to the documentation of this file.

#pragma once
 
// Fast socket monitoring for ESP32 and LibreTiny (LwIP >= 2.1.3)
// Replaces lwip_select() with direct rcvevent reads and FreeRTOS task notifications.
 
#include <stdbool.h>
#include <stdint.h>
 
// Forward declare lwip_sock for C++ callers that store cached pointers.
// The full definition is only available in the .c file (lwip/priv/sockets_priv.h
// conflicts with C++ compilation units).
struct lwip_sock;
 
// Byte offset of rcvevent (s16_t) within struct lwip_sock.
// Verified at compile time in lwip_fast_select.c via _Static_assert.
// Anonymous enum for a compile-time constant that works in both C and C++.
enum { ESPHOME_LWIP_SOCK_RCVEVENT_OFFSET = 8 };
 
#ifdef __cplusplus
extern "C" {
#endif
 
struct lwip_sock *esphome_lwip_get_sock(int fd);
 
static inline bool esphome_lwip_socket_has_data(struct lwip_sock *sock) {
  // Unlocked hint read — no lwIP core lock needed.
  // volatile prevents the compiler from caching/reordering this cross-thread read.
  // The write side (TCP/IP thread) commits via SYS_ARCH_UNPROTECT which releases a
  // FreeRTOS mutex (ESP32) or resumes the scheduler (LibreTiny), ensuring the value
  // is visible. Aligned 16-bit reads are single-instruction loads (L16SI/LH/LDRH) on
  // Xtensa/RISC-V/ARM and cannot produce torn values.
  return *(volatile int16_t *) ((char *) sock + (int) ESPHOME_LWIP_SOCK_RCVEVENT_OFFSET) > 0;
}
 
void esphome_lwip_hook_socket(struct lwip_sock *sock);
 
void esphome_fast_select_set_ota_listener_sock(struct lwip_sock *sock);
 
bool esphome_lwip_set_nodelay(struct lwip_sock *sock, bool enable);
 
#ifdef __cplusplus
}
#endif