Rob Kardashian and Blac Chyna are close to an agreement for custody and child support. TMZ was told by sources that the lawyers from both sides as well as Rob and Chyna themselves have been hashing out a joint custody arrangement for months. We're told they are not far apart over the division of physical custody, each is fine giving the other substantial physical custody.

It's significant because the Dept. of Children and Family Services opened a case even before Rob and Chyna split over her alleged drug use. We're told it's still an open case in L.A. County Dependency Court.

Rob believes Chyna can handle parental responsibilities. We're told, however, the Kardashian women are not as understanding and believe there are serious questions about Chyna's fitness because of the drug allegations.

However, there's something more problematic, child support.  Sources told TMZ Chyna wants a lot way more than Rob thinks she deserves, but it appears there's been some movement toward a compromise.