CONFIG_IP_NF_TARGET_TOS
FTOS target support
CONFIG_IP_NF_TARGET_FTOS
  This option adds a `FTOS' target, which allows you to create rules in
  the iptables mangle table. The selected packet has the TOS field set
  to the hex value provided on the command line; unlike the TOS target
  which will only set the legal values within ip.h.

  The TOS field can be set to any value between 0x0 and 0xff. It does
  not take account of the DiffServ field split nor does it account for
  the ECN bit states.

  Basically you can use it to set the TOS field to whatever value you want.

  If you want to compile it as a module, say M here and read
  Documentation/modules.txt.  If unsure, say `N'.

 