ICMP.cpp

/*
  Created by Fabrizio Di Vittorio (fdivitto2013@gmail.com) - <http://www.fabgl.com>
  Copyright (c) 2019-2020 Fabrizio Di Vittorio.
  All rights reserved.

  This file is part of FabGL Library.

  FabGL 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.

  FabGL 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 FabGL.  If not, see <http://www.gnu.org/licenses/>.
 */


#ifdef ARDUINO


#include "ICMP.h"

#include "Arduino.h"
#include "WiFiGeneric.h"


namespace fabgl {


ICMP::ICMP()
  : m_queue(xQueueCreate(1, sizeof(uint8_t))), m_waitingID(rand() & 0xFFFF), m_waitingSeq(-1)
{
}


ICMP::~ICMP()
{
  vQueueDelete(m_queue);
}


// -1 = timeout
// -2 = cannot resolve name
int ICMP::ping(char const * host)
{
  IPAddress hostIP((uint32_t)0);
  if (!WiFiGenericClass::hostByName(host, hostIP))
    return -2;
  return ping(hostIP);
}


// -1 = timeout
int ICMP::ping(IPAddress const &dest)
{
  static int32_t const TIMEOUT        = 1000;
  static int32_t const TIMEOUT_RESULT = -1;

  m_destIP = dest;

  int result = TIMEOUT_RESULT;

  // generate seq
  ++m_waitingSeq;

  // prepare packet to send
  pbuf * hdrbuf = pbuf_alloc(PBUF_IP, sizeof(icmp_echo_hdr), PBUF_RAM);
  icmp_echo_hdr * hdr = (icmp_echo_hdr *) hdrbuf->payload;
  hdr->type   = ICMP_ECHO;
  hdr->code   = 0;
  hdr->chksum = 0;
  hdr->id     = htons(m_waitingID);
  hdr->seqno  = htons(m_waitingSeq);
  hdr->chksum = inet_chksum((uint16_t *) hdr, sizeof(icmp_echo_hdr));

  // send Echo request
  raw_pcb * pcb = raw_new(IP_PROTO_ICMP);
  raw_recv(pcb, ICMP::raw_recv_fn, this);
  raw_bind(pcb, IP_ADDR_ANY);

  ip_addr_t addr;
  addr.type = IPADDR_TYPE_V4;
  addr.u_addr.ip4.addr = dest;
  raw_sendto(pcb, hdrbuf, &addr);
  pbuf_free(hdrbuf);

  result = -1;
  int32_t t1 = micros();
  uint8_t c;
  if (xQueueReceive(m_queue, &c, pdMS_TO_TICKS(TIMEOUT)))
    result = micros() - t1;
  raw_remove(pcb);

  return result;
}


uint8_t ICMP::raw_recv_fn(void * arg, raw_pcb * pcb, pbuf * p, const ip_addr_t * addr)
{
  ICMP * this_ = (ICMP *)arg;

  ip_hdr * iphdr = (ip_hdr *)p->payload;

  int ttl = IPH_TTL(iphdr);

  if (p->tot_len >= sizeof(ip_hdr) + sizeof(icmp_echo_hdr) && pbuf_header(p, -(s16_t)sizeof(ip_hdr)) == 0) {
    icmp_echo_hdr * hdr = (icmp_echo_hdr *) p->payload;
    if (ntohs(hdr->id) == this_->m_waitingID && ntohs(hdr->seqno) == this_->m_waitingSeq) {
      this_->m_receivedBytes = p->tot_len;
      this_->m_receivedTTL = ttl;
      uint8_t c = 0;
      xQueueSendToBack(this_->m_queue, &c, portMAX_DELAY);
    }
    pbuf_free(p);
    return 1;
  }

  return 0;
}



}



#endif // #ifdef ARDUINO