MFC r223666:

MFC r223666:
  Add new rule actions "call" and "return" to ipfw. They make
  possible to organize subroutines with rules.

  The "call" action saves the current rule number in the internal
  stack and rules processing continues from the first rule with
  specified number (similar to skipto action). If later a rule with
  "return" action is encountered, the processing returns to the first
  rule with number of "call" rule saved in the stack plus one or higher.

  Submitted by:	Vadim Goncharov

git-svn-id: svn://svn.freebsd.org/base/stable/8@230575 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f