MFC 1.87:   In order to support CARP interfaces kernel was taught to handle more   than one interface in one subnet. However, some userland apps rely on   the believe that this configuration is impossible.
MFC 1.87:
  In order to support CARP interfaces kernel was taught to handle more
  than one interface in one subnet. However, some userland apps rely on
  the believe that this configuration is impossible.

  Add a sysctl switch net.inet.ip.same_prefix_carp_only. If the switch
  is on, then kernel will refuse to add an additional interface to
  already connected subnet unless the interface is CARP. Default
  value is off.

  PR:				bin/82306
  In collaboration with:	mlaier

Approved by:	re (scottl)

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase