What is the legal ruling on cupping (hijama), and are all actions of the Messenger (peace be upon him) considered Sunnah, whether they are acts of worship or his personal actions?

The actions of the Prophet, peace and blessings be upon him, are of five types: those that are inborn (jibiliyyah); no command or prohibition is related to them, except for any additional qualities accompanying them, in which case emulation is recommended. Those that are customary; it cannot be said that following him in them is a Sunnah except for specific attributes attached to them, but if a person emulates them, he will be rewarded. Those that are absolute, where neither the intention of seeking proximity to Allah nor its absence is apparent; the correct view is that emulation of them is commendable. Those that came to specify a general ruling, restrict an absolute one, or explain an ambiguous one; their ruling is the same as the ruling they clarify. And those that are exclusive to him; there is no emulation of him in them.