Tasmota/tasmota/tasmota_xdrv_driver/xdrv_41_tcp_bridge.ino

/*
  xdrv_41_tcp_bridge.ino - TCP to serial bridge

  Copyright (C) 2021  Theo Arends and Stephan Hadinger

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifdef USE_TCP_BRIDGE

#define XDRV_41                    41

#ifndef TCP_BRIDGE_CONNECTIONS
#define TCP_BRIDGE_CONNECTIONS 2    // number of maximum parallel connections
#endif

#ifndef TCP_BRIDGE_BUF_SIZE
#define TCP_BRIDGE_BUF_SIZE    255  // size of the buffer, above 132 required for efficient XMODEM
#endif

//const uint16_t tcp_port = 8880;
WiFiServer   *server_tcp = nullptr;
//WiFiClient   client_tcp1, client_tcp2;
WiFiClient   client_tcp[TCP_BRIDGE_CONNECTIONS];
uint8_t      client_next = 0;
uint8_t     *tcp_buf = nullptr;     // data transfer buffer
IPAddress    ip_filter;

#include <TasmotaSerial.h>
TasmotaSerial *TCPSerial = nullptr;

const char kTCPCommands[] PROGMEM = "TCP" "|"    // prefix
  "Start" "|" "Baudrate" "|" "Config" "|" "Connect"
  ;

void (* const TCPCommand[])(void) PROGMEM = {
  &CmndTCPStart, &CmndTCPBaudrate, &CmndTCPConfig, &CmndTCPConnect
  };

//
// Called at event loop, checks for incoming data from the CC2530
//
void TCPLoop(void)
{
  uint8_t c;
  bool busy;    // did we transfer some data?
  int32_t buf_len;

  if (!TCPSerial) return;

  // check for a new client connection
  if ((server_tcp) && (server_tcp->hasClient())) {
    WiFiClient new_client = server_tcp->available();

    AddLog(LOG_LEVEL_INFO, PSTR(D_LOG_TCP "Got connection from %s"), new_client.remoteIP().toString().c_str());
    // Check for IP filtering if it's enabled.
    if (ip_filter) {
      if (ip_filter != new_client.remoteIP()) {
        AddLog(LOG_LEVEL_INFO, PSTR(D_LOG_TCP "Rejected due to filtering"));
        new_client.stop();
      } else {
        AddLog(LOG_LEVEL_INFO, PSTR(D_LOG_TCP "Allowed through filter"));
      }
    }

    // find an empty slot
    uint32_t i;
    for (i=0; i<nitems(client_tcp); i++) {
      WiFiClient &client = client_tcp[i];
      if (!client) {
        client = new_client;
        break;
      }
    }
    if (i >= nitems(client_tcp)) {
      i = client_next++ % nitems(client_tcp);
      WiFiClient &client = client_tcp[i];
      client.stop();
      client = new_client;
    }
  }

  do {
    busy = false;       // exit loop if no data was transferred

    // start reading the UART, this buffer can quickly overflow
    buf_len = 0;
    while ((buf_len < TCP_BRIDGE_BUF_SIZE) && (TCPSerial->available())) {
      c = TCPSerial->read();
      if (c >= 0) {
        tcp_buf[buf_len++] = c;
        busy = true;
      }
    }
    if (buf_len > 0) {
      AddLog(LOG_LEVEL_DEBUG_MORE, PSTR(D_LOG_TCP "from MCU: %*_H"), buf_len, tcp_buf);

      for (uint32_t i=0; i<nitems(client_tcp); i++) {
        WiFiClient &client = client_tcp[i];
        if (client) { client.write(tcp_buf, buf_len); }
      }
    }

    // handle data received from TCP
    for (uint32_t i=0; i<nitems(client_tcp); i++) {
      WiFiClient &client = client_tcp[i];
      buf_len = 0;
      while (client && (buf_len < TCP_BRIDGE_BUF_SIZE) && (client.available())) {
        c = client.read();
        if (c >= 0) {
          tcp_buf[buf_len++] = c;