WiFiUdp.cpp

/*
  This file is part of the Arduino NINA firmware.
  Copyright (c) 2018 Arduino SA. All rights reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include <errno.h>
#include <string.h>

#include <lwip/netdb.h>
#include <lwip/sockets.h>

#include "WiFiUdp.h"

WiFiUDP::WiFiUDP() :
  _socket(-1),
  _remoteIp(0),
  _remotePort(0),
  _rcvIndex(0),
  _rcvSize(0),
  _sndSize(0)
{
}

uint8_t WiFiUDP::begin(uint16_t port)
{
  _socket = lwip_socket(AF_INET, SOCK_DGRAM, 0);

  if (_socket < 0) {
    return 0;
  }

  struct sockaddr_in addr;
  memset(&addr, 0x00, sizeof(addr));

  addr.sin_family = AF_INET;
  addr.sin_addr.s_addr = (uint32_t)0;
  addr.sin_port = htons(port);

  if (lwip_bind(_socket, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
    lwip_close_r(_socket);
    _socket = -1;
    return 0;
  }

  int nonBlocking = 1;
  lwip_ioctl_r(_socket, FIONBIO, &nonBlocking);

  return 1;
}

uint8_t WiFiUDP::beginMulticast(/*IPAddress*/uint32_t ip, uint16_t port)
{
  if (!begin(port)) {
    return 0;
  }

  struct ip_mreq multi;

  multi.imr_multiaddr.s_addr = (uint32_t)ip;
  multi.imr_interface.s_addr = (uint32_t)0;

  lwip_setsockopt_r(_socket, IPPROTO_IP, IP_ADD_MEMBERSHIP, &multi, sizeof(multi));

  return 1;
}

/* return number of bytes available in the current packet,
   will return zero if parsePacket hasn't been called yet */
int WiFiUDP::available()
{
  return (_rcvSize - _rcvIndex);
}

/* Release any resources being used by this WiFiUDP instance */
void WiFiUDP::stop()
{
  lwip_close_r(_socket);
  _socket = -1;
}

int WiFiUDP::beginPacket(const char *host, uint16_t port)
{
  struct hostent* server = gethostbyname(host);

  if (server == NULL) {
      return 0;
  }

  return beginPacket(server->h_addr, port);
}

int WiFiUDP::beginPacket(/*IPAddress*/uint32_t ip, uint16_t port)
{
  _remoteIp = ip;
  _remotePort = port;

  _sndSize = 0;

  return 1;
}

int WiFiUDP::endPacket()
{
  struct sockaddr_in addr;
  memset(&addr, 0x00, sizeof(addr));

  addr.sin_family = AF_INET;
  addr.sin_addr.s_addr = _remoteIp;
  addr.sin_port = htons(_remotePort);

  if (lwip_sendto(_socket, _sndBuffer, _sndSize, 0, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
    return 0;
  }

  return 1;
}

size_t WiFiUDP::write(uint8_t byte)
{
  return write(&byte, 1);
}

size_t WiFiUDP::write(const uint8_t *buffer, size_t size)
{
  size_t written = size;

  if ((_sndSize + size) > sizeof(_sndBuffer)) {
    written = sizeof(_sndBuffer) - _sndSize;
  }

  memcpy(&_sndBuffer[_sndSize], buffer, size);

  _sndSize += written;

  return written;
}

int WiFiUDP::parsePacket()
{
  struct sockaddr_in addr;
  socklen_t addrLen = sizeof(addr);

  _rcvIndex = 0;
  _rcvSize = 0;

  int result = lwip_recvfrom_r(_socket, _rcvBuffer, sizeof(_rcvBuffer), MSG_DONTWAIT, (struct sockaddr*)&addr, &addrLen);

  if (result <= 0) {
    return 0;
  }

  _rcvSize = result;
  _remoteIp = addr.sin_addr.s_addr;
  _remotePort = ntohs(addr.sin_port);

  return result;
}

int WiFiUDP::read()
{
  uint8_t b;

  if (read(&b, sizeof(b)) < 1) {
    return -1;
  }

  return b;
}

int WiFiUDP::read(unsigned char* buf, size_t size)
{
  if (available() < (int)size) {
    size = available();
  }

  memcpy(buf, &_rcvBuffer[_rcvIndex], size);

  _rcvIndex += size;

  return size;
}

int WiFiUDP::peek()
{
  if (!available()) {
    return -1;
  }

  return _rcvBuffer[_rcvIndex];
}

void WiFiUDP::flush()
{
}

/*IPAddress*/uint32_t WiFiUDP::remoteIP()
{
  return _remoteIp;
}

uint16_t  WiFiUDP::remotePort()
{
  return _remotePort;
}