boost::asio::ip::network_v6::hosts has a BUG to represent address_v6_range of "::/0"

[bcdong]

code position: https://github.com/boostorg/asio/blob/e65367991cb5fbdb8a7cf218ae38f69ca9a0a9f5/include/boost/asio/ip/impl/network_v6.ipp#L78

address_v6_range network_v6::hosts() const noexcept
{
  address_v6::bytes_type begin_bytes(address_.to_bytes());
  address_v6::bytes_type end_bytes(address_.to_bytes());
  for (std::size_t i = 0; i < 16; ++i)
  {
    if (prefix_length_ <= i * 8)
    {
      begin_bytes[i] = 0;
      end_bytes[i] = 0xFF;
    }
    else if (prefix_length_ < (i + 1) * 8)
    {
      begin_bytes[i] &= 0xFF00 >> (prefix_length_ % 8);
      end_bytes[i] |= 0xFF >> (prefix_length_ % 8);
    }
  }
  return address_v6_range(
      address_v6_iterator(address_v6(begin_bytes, address_.scope_id())),
      ++address_v6_iterator(address_v6(end_bytes, address_.scope_id())));
}

The above code returns an address_v6_range with the end being ++address_v6_iterator(address_v6(end_bytes, address_.scope_id())));. If the network CIDR is ::/0, which should contains all valid ipv6 addresses, the end_bytes will be 0xFFF...FFF. And the ++ operator will make the address_v6_range [0x00..00, ++ 0xFF...FF) overflow to [0x00..00, 0x00..00). This network range contains no ipv6 addresses.