Tamron AF 70-300mm f/4.0-5.6 Di LD Macro Zoom Lens for canon dslr?

is this just a normal macro zoom lens or is it some kind of... knock off of a macro lens like a macro extension tube or a macro filter? i know the brand is a knock off, but you know what i mean right? does it have the same quality of a canon macro lens or is it crap