Generals Alpha is an OpenRA mod that recreates Command & Conquer: Generals on OpenRA engine as much as possible but using Red Alert and Tiberian Dawn artworks.
Garrison was another thing that Generals Alpha lacked but one of my other mods had, so along with the engine update, i've also implemented a the garrison logic. The buildings show a remapped flag on them when they are garrisoned, and the usual counter units can deal damage to the infantry in the building.