aliastable.cc

COPE the first practical network coding scheme which is developped on click

#include <click/config.h>
#include <click/confparse.hh>
#include <click/error.hh>
#include <click/glue.hh>
#include <click/straccum.hh>
#include <click/timestamp.hh>
#include <click/string.hh>
#include <clicknet/ether.h>
#include "aliastable.hh"

CLICK_DECLS
#define FNV1_32_INIT ((uint32_t)0x811c9dc5)
#define FNV_32_PRIME ((uint32_t)0x01000193)
#define MASK_16 (((uint32_t)1<<16)-1)
#define MASK_8 (((uint32_t)1<<8)-1)

AliasTable::AliasTable()
  : Element(0,0)
{
  uint8_t data[6];

  memset(data, 0xFF, sizeof(uint8_t)*6);
  _bcast = EtherAddress(data);
}

AliasTable::~AliasTable()
{
}

const EtherAddress &
AliasTable::get_random_neighbor(const EtherAddress& myea) 
{
  for (AliasTableType::const_iterator i=_alias_table.begin(); i!=_alias_table.end(); i++) {
    if (i.key()!= myea) {
      return i.key();
    }
  }
  return _bcast;
}


void *
AliasTable::cast(const char *n)
{
  if (strcmp(n, "AliasTable") == 0)
    return (AliasTable *) this;
  else
    return 0;
}

uint8_t
AliasTable::lookup(const EtherAddress& addr) 
{
  uint8_t nbid;
  StringAccum sa;
  sa << addr << ' ';
  nbid = _alias_table.find(addr);
  if (nbid) return nbid;
  nbid = gen_alias(addr);
  _alias_table.insert(addr, nbid);
  _alias_table_rev.insert(nbid, addr);
  return nbid;
}


unsigned char*
AliasTable::lookup_addr(uint8_t nbid) 
{
  EtherAddress addr = _alias_table_rev.find(nbid);
  return addr.data();
}

uint8_t 
AliasTable::gen_alias(EtherAddress addr)
{
  return hashint(addr);
}

uint8_t hashint(const EtherAddress& addr) {
  const unsigned char *d = addr.data();
  uint32_t hval = FNV1_32_INIT;
  
  int i = 0;
  while(i < 6) {
      hval *= FNV_32_PRIME;
      hval ^= (uint32_t)(*d++);
      i++;
  }

  hval = (hval>>8) ^ (hval&MASK_8);
  return (uint8_t)hval;
}

#include <click/bighashmap.cc>
#include <click/vector.cc>
#if EXPLICIT_TEMPLATE_INSTANCES
template class HashMap<EtherAddress, uint8_t>;
#endif
CLICK_ENDDECLS
EXPORT_ELEMENT(AliasTable)