/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
 *            multicast.cc
 *
 *  Mon Sep 26 12:25:22 CEST 2005
 *  Copyright  2005 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of MIaV.
 *
 *  MIaV 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  MIaV 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 MIaV; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */
#include "config.h"
#include "multicast.h"

#include <netinet/in.h>
#include <netdb.h>
#include <sys/socket.h>
#include <sys/param.h>
#include <arpa/inet.h>

Multicast::Multicast(Info *i, char *addr, int port)
{
  /*
    Multicast adresses:
    224.0.0.1 All systems on this subnet
    224.0.0.2 All routers on this subnet
    224.0.0.5 OSPF routers
    224.0.0.6 OSPF designated routers
    224.0.0.12 DHCP server/relay agent
server_multicast	= true
server_multicast_addr	= "224.0.0.1"
server_multicast_port	= 1234
  */

  // Multicast to all systems on this subnet
  //  char addr[] = "224.0.0.1";
  //  int port = 1234;

  info = i;
  if(!UDPOpen(addr, port)) info->error("Error creating socket %s:%d", addr, port);
}

Multicast::~Multicast()
{
}

void Multicast::Write(void* buf, int size)
{
  //  char addr[] = "192.168.0.10";
  //  int port = 1234;

  if(write(sock, buf, size) != size) {
    info->error("Error Writing to socket.");
    //    if(!UDPOpen(addr, port)) info->error("Error creating socket %s:%d", addr, port);
  }
}

#define USE_MULTICAST

bool Multicast::is_address_multicast(unsigned long address)
{
  if((address & 255) >= 224 && (address & 255) <= 239) {
    info->info("Address is multicast.");
    return true;
  }
    info->info("Address is NOT multicast.");
  return false;
}

/*
 * open UDP socket
 */
bool Multicast::UDPOpen(char *address, int port)
{
  int enable = 1L;
  struct sockaddr_in stAddr;
  struct sockaddr_in stLclAddr;
  struct hostent * host;
  //  int sock;
  
  stAddr.sin_family = AF_INET;
  stAddr.sin_port = htons(port);
  if((host = gethostbyname(address)) == NULL) return false;
  stAddr.sin_addr = *((struct in_addr *) host->h_addr_list[0]);

  // Create a UDP socket
  if((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
        return false;

  // Allow multiple instance of the client to share the same address and port
  if(setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *) &enable, sizeof(unsigned long int)) < 0) 
    return false;

#ifdef USE_MULTICAST
  // If the address is multicast, register to the multicast group
  if(is_address_multicast(stAddr.sin_addr.s_addr))
  {
    struct ip_mreq stMreq;
  
    // Bind the socket to port
    stLclAddr.sin_family      = AF_INET;
    stLclAddr.sin_addr.s_addr = htonl(INADDR_ANY);
    stLclAddr.sin_port        = stAddr.sin_port;
    if(bind(sock, (struct sockaddr*) & stLclAddr, sizeof(stLclAddr)) < 0) return false;

    // Register to a multicast address
    stMreq.imr_multiaddr.s_addr = stAddr.sin_addr.s_addr;
    stMreq.imr_interface.s_addr = INADDR_ANY;
    if(setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) & stMreq, sizeof(stMreq)) < 0) 
      return false;
  }
  else
#endif
  {
    // Bind the socket to port
    stLclAddr.sin_family      = AF_INET;
    stLclAddr.sin_addr.s_addr = htonl(INADDR_ANY);
    stLclAddr.sin_port        = htons(0);
    if(bind(sock, (struct sockaddr*) & stLclAddr, sizeof(stLclAddr)) < 0)
        return false;
  }

  connect(sock, (struct sockaddr*) & stAddr, sizeof(stAddr));

  return true;
}