Determine all functions f:R→Rf: \mathbb{R} \to \mathbb{R}f:R→R such that f(xf(y)+2y)=f(xy)+xf(y)+f(f(y))f(xf(y) + 2y) = f(xy) + xf(y) + f(f(y))f(xf(y)+2y)=f(xy)+xf(y)+f(f(y)) holds for all real numbers xxx and yyy.