static char *IGNORES[] = {
    "127.",             // localhost
    "0:0:0:0:0:0:0:1",  // localhost
    "ff02:0:0:0:0:1:",  // 
    (char*)0
};

// Return the size of the IGN table
static int IGN_count() {
    int i = 0;
    while ( IGNORES[ i ] != 0 ) {
	i++;
    }
    return i;
}

/**
 * Compare an IP against an ignore entry of width w.
 * return 0 if ip starts with ign, <0 if ip < ign, and >0 if ip > ign
 */
static int IGN_cmp(const void *ipx, const void *ignx) {
    char *ip = (char *) ipx;
    char *ign = *(char**) ignx;
    while ( *ign ) {
	if ( *ip == 0 ) {
	    return -1;
	}
	int c = *(ip++) - *(ign++);
	if ( c ) {
	    return c;
	}
    }
    return 0;
}

static int ignored(char *ip) {
    static int IGN_size = -1;
    if ( IGN_size == -1 ) {
	IGN_size = IGN_count();
    }
    return bsearch( ip, IGNORES, IGN_size, sizeof( char* ), IGN_cmp )? 1 : 0;
}