For the objective function, you just need need the H to be [1 0 0; 0 0 0; 0 0 0] assuming each of w,eta, and b are scalar quantities. In order to generalize this idea for vector w,eta, and b. You need H to be a multidimensional array so that the dimensions match when you are trying to do [w' eta' b']*H*[w eta b]. Another quantity required is "f" and it should be of the form [0; c; 0].
The constraints are linear as well. You can follow a similar method for setting up the constraints. Hope it helps!