I have an oak that presents many ants on its bark, and I feel that its bark looks sick (even though I'm not an expert, so it's just a feeling). Furthermore, there is a big fungus at the trunk's base. Here are some images:
Here are three photos of the bark:
And here's a photo of the fungus:
Is this oak sick? If so, what can I do in order to treat it?
UPDATE
Here are other photos of the fungus: