
  This option adds a `IPMARK' target, which allows you to mark
  a received packet basing on its IP address. This can replace many
  mangle/mark entries with only one, if you use firewall based
  classifier.

  This target is to be used inside the mangle table, in the PREROUTING,
  POSTROUTING or FORWARD hooks.

  IPMARK target options:
    --addr src/dst      Use source or destination IP address.
    --and-mask mask     Perform bitwise `and' on the IP address and this mask.
    --or-mask mask      Perform bitwise `or' on the IP address and this mask.

  The order of IP address bytes is reversed to meet "human order of bytes":
  192.168.0.1 is 0xc0a80001. At first the `and' operation is performed, then
  `or'.

  Examples:

  We create a queue for each user, the queue number is adequate
  to the IP address of the user, e.g.: all packets going to/from 192.168.5.2
  are directed to 1:0502 queue, 192.168.5.12 -> 1:050c etc.

  We have one classifier rule:
  tc filter add dev eth3 parent 1:0 protocol ip fw

  Earlier we had many rules just like below:
  iptables -t mangle -A POSTROUTING -o eth3 -d 192.168.5.2 -j MARK
    --set-mark 0x10502
  iptables -t mangle -A POSTROUTING -o eth3 -d 192.168.5.3 -j MARK
    --set-mark 0x10503
  ...

  Using IPMARK target we can replace all the mangle/mark rules with only one:
  iptables -t mangle -A POSTROUTING -o eth3 -j IPMARK --addr=dst
    --and-mask=0xffff --or-mask=0x10000

  On the routers with hundreds of users there should be significant load
  decrease (e.g. twice).
