/*
 * Module: netlink_event.cc
 *
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */
#include <sys/types.h>
#include <sys/socket.h>
#include <linux/rtnetlink.h>
#include <net/if.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <syslog.h>

#include <iostream>
#include <string>
#include "netlink_event.hh"

using namespace std;

/**
 *
 *
 **/
NetlinkEvent::NetlinkEvent(int type,
			   std::string iface,
			   int mtu,
			   unsigned char *mac,
			   bool enabled,
			   bool running,
			   IPv4 local,
			   IPv4 addr,
			   IPv4 broadcast,
			   int mask_len,
			   int index) :
  _type(type),
  _iface(iface),
  _vif(false),
  _mtu(mtu),
  _enabled(enabled),
  _running(running),
  _local(local),
  _addr(addr),
  _broadcast(broadcast),
  _mask_len(mask_len),
  _index(index)
{
  memcpy(_mac, mac, 6);
  if (_iface.find(".") != string::npos) {
    _vif = true;
  }
}

/**
 *
 *
 **/
NetlinkEvent::~NetlinkEvent()
{
}

/**
 *
 *
 **/
void
NetlinkEvent::log()
{
  syslog(LOG_USER | LOG_INFO, "NetlinkEvent::log(): type: %d, iface: %s, mtu: %d, local: %s, addr: %s, bc: %s, mask: %d, index: %d", _type, _iface.c_str(), _mtu, _local.str().c_str(), _addr.str().c_str(), _broadcast.str().c_str(), _mask_len, _index);
}

/**
 *
 *
 **/
NetlinkEventManager::NetlinkEventManager(bool debug) :
  _debug(debug)
{

}

/**
 *
 *
 *
 **/
NetlinkEventManager::~NetlinkEventManager()
{
}

/**
 *
 *
 *
 **/
void
NetlinkEventManager::process(unsigned char* pkt, int size)
{
  if (size <= 0) {
    return;
  }

  size_t ps = size_t(size);

  const struct nlmsghdr* mh;
  for (mh = reinterpret_cast<const struct nlmsghdr*>(pkt);
       NLMSG_OK(mh, ps);
       mh = NLMSG_NEXT(const_cast<struct nlmsghdr*>(mh), ps)) {
    parse_msg(mh);
  }
}

/**
 *
 *
 **/
bool
NetlinkEventManager::pop(NetlinkEvent &e)
{
  char buf[20];
  sprintf(buf, "%d", _coll.size());
  
  NLEventIter iter = _coll.begin();
  if (iter != _coll.end()) {
    e = *iter;
    _coll.erase(iter);
    return true;
  }
  return false;
}

/**
 *
 *
 *
 **/
void 
NetlinkEventManager::parse_msg(const struct nlmsghdr *nlHdr)
{
  bool enabled;
  bool running;
  string iface;
  int mtu = -1;
  int index = -1;
  unsigned char mac[6];
  IPv4 addr, local, broadcast;
  int mask_len = -1;

  bzero(mac, 6);

  struct ifinfomsg* ifInfo = (struct ifinfomsg *)NLMSG_DATA(nlHdr);

  //link state flag 
  enabled = ifInfo->ifi_flags & IFF_UP;
  running = ifInfo->ifi_flags & IFF_RUNNING;
  index = ifInfo->ifi_index;

  struct rtattr* rtAttr = (struct rtattr *)IFLA_RTA(ifInfo);
  int rtLen = IFLA_PAYLOAD(nlHdr);

  switch (nlHdr->nlmsg_type) {
  case RTM_NEWLINK:
  case RTM_DELLINK:
  case RTM_NEWADDR:
  case RTM_DELADDR:
    for(;RTA_OK(rtAttr,rtLen);rtAttr = RTA_NEXT(rtAttr,rtLen)){
      if (nlHdr->nlmsg_type == RTM_NEWLINK ||
	  nlHdr->nlmsg_type == RTM_DELLINK) {
	switch(rtAttr->rta_type) {
	case IFLA_IFNAME:
	  iface = string((char*)RTA_DATA(rtAttr));
	  break;
	case IFLA_ADDRESS:
	  memcpy(mac, RTA_DATA(rtAttr), 6);
	  break;
	case IFLA_MTU:
	  mtu = *((unsigned int *)RTA_DATA(rtAttr));
	  break;
	default:
	  break;
	}
      }
      else if (nlHdr->nlmsg_type == RTM_NEWADDR ||
	       nlHdr->nlmsg_type == RTM_DELADDR) {
	uint32_t address;
	struct ifaddrmsg *ifAddrs;
	ifAddrs = (struct ifaddrmsg *)NLMSG_DATA(nlHdr);
	mask_len = ifAddrs->ifa_prefixlen;

	switch(rtAttr->rta_type) {
	case IFA_LOCAL:
	  address = *(uint32_t *)RTA_DATA(rtAttr);
	  local = IPv4(address);
	  break;
	case IFA_ADDRESS:
	  address = *(uint32_t *)RTA_DATA(rtAttr);
	  addr = IPv4(address);
	  break;
	case IFA_LABEL:
	  iface = string((char*)RTA_DATA(rtAttr));
	  break;
	case IFA_BROADCAST:
	  address = *(uint32_t *)RTA_DATA(rtAttr);
	  broadcast = IPv4(address);
	  break;
	default:
	  break;
	}
      }
    }
    {
      NetlinkEvent e(nlHdr->nlmsg_type,
		     iface,
		     mtu,
		     mac,
		     enabled,
		     running,
		     local,
		     addr,
		     broadcast,
		     mask_len,
		     index);

      e.set_ifinfomsg(ifInfo);
      
      if (_debug) {
	e.log();
      }
      _coll.push_back(e);
    }
    break;
  case NLMSG_ERROR: {
    struct nlmsgerr *err = (struct nlmsgerr*) NLMSG_DATA(nlHdr);
    //drop down to info as this can be caused on startup by downed interfaces that are requested for dump, or attempting to remove routes on downed interface after startup (if they have already been removed).
    syslog(LOG_INFO,"netlink message of type ERROR received: %s",strerror(-err->error));
    //    cerr << "netlink message of type ERROR received: " ;
    //    cerr << string(strerror(-err->error)) << endl;
  }
    break;
  case NLMSG_DONE:
    //    if (_debug) {
    //      cout << "netlink message of type DONE received" << endl;
    //    }
    break;
  case NLMSG_NOOP:
    syslog(LOG_INFO,"netlink message of type NOOP received");
    break;
  default:
    syslog(LOG_INFO,"unknown netlink message type received");
    break;
  }
}


/**
 *
 *
 *
 **/
typedef struct {
  unsigned int iff_flag;
  char *name;
} iff_flags_name;


string
NetlinkEvent::get_ifinfomsg()
{
  string ret;
  char buf[40];

  sprintf(buf, "%u", _ifinfo.ifi_family);
  ret = "ifi_family: " + string(buf) + ", ";
  sprintf(buf, "%u", _ifinfo.ifi_type);
  ret += "ifi_type: " + string(buf) + ", ";
  sprintf(buf, "%d", _ifinfo.ifi_index);
  ret += "ifi_index: " + string(buf) + ", ";
  sprintf(buf, "%u", _ifinfo.ifi_flags);
  ret += "ifi_flags: " + string(buf) + ", ";
  sprintf(buf, "%u", _ifinfo.ifi_change);
  ret += "ifi_change: " + string(buf);
  return ret;
}

/*
string
NetlinkEvent::operator<<(const ostream &o)
{
    UNUSED(o);
  return ("");
}
*/
std::ostream & operator <<(std::ostream & Stream, const NetlinkEvent & instance) 
{ 
  //  Stream << ... fields from instance 
  const NetlinkEvent foo = instance;
  return Stream; 
}


/* from quagga prefix.c */
/* Apply mask to IPv4 prefix. */
/* Maskbit. */
static u_char maskbit[] = {0x00, 0x80, 0xc0, 0xe0, 0xf0,
                                 0xf8, 0xfc, 0xfe, 0xff};


uint32_t
apply_mask_ipv4 (const uint32_t p, const unsigned char m)
{
  uint32_t val(p);
  u_char *pnt = (u_char *) &val;
  int index;
  int offset;

  index = m / 8;
  if (index < 4) {
    offset = m % 8;
    
    pnt[index] &= maskbit[offset];
    index++;
    
    while (index < 4) {
      pnt[index++] = 0;
    }
  }
  return val;
}