What is the halo games timelines

halo wars: 20 years before end of war
halo reach: 7 years before end of war
halo 1: beginning of the discovery of the rings
halo 2: several years after halo 1 during earth invasion
halo ODST: few minutes after covenant ship jump in halo 2
halo 3: end of the 30 year war
halo 4: 4 years after end of war and begining of new war