ripd: Fix restriction on default RTE that's incompatible with CIDR

* ripd.c: (rip_response_process) A 0 address can still easily have a
  non-zero netmask.  E.g., 0/1 to complement 128/1.  These should be allowed
  through. See bug #903.

  Modify to check for malformed pseudo-default routes, where the netmask is
  0 but the address is non-0, and warn and drop such routes instead.
1 file changed