Lets see...
Under the guise of fighting IS, the Turks are bombing the Kurds and attacking them politically within Turkey, potentially starting another war. The Kurds are of course the most effective anti-IS force on the ground
France, the US, Australia and the UK are bombing IS in Syria & Iraq whilst also providing support and training to other non-IS rebel groups.
The Arab league, Qatar and the Saudis are arming various rebel groups and threatening direct intervention.
The Russians are now using the refugee crisis as an excuse to bomb the main threats to Assad from non-IS rebel groups, including CIA trained groups and supported by various East Europeans and the Chinese.
Iran & Hezbollah are offering technical and independent military support of Assad.
Neighbouring countries, including Jordan, Israel and Lebanon are all involved either directly or covertly.
Every other bunch of scumbags in the planet including Croatia and North Korea are either shipping arms to, or supporting one faction or another.
Practically all of these interventions are illegal under IL, except possibly, the Russians and their allies.
Presumably the 'plan' now is to wipe out opposition to Assad one way or another and allow him to step down with some kind of puppet government set up to manage a 'transition' to democracy and then deal with IS.
Undoubtedly the prospects of a descent into a regional and then global conflagration are far more realistic. This makes Lebanon look like a tea party.