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.
.TP
.BI "--addr " "src/dst"
Use source or destination IP address.
.TP
.BI "--and-mask " "mask"
Perform bitwise `and' on the IP address and this mask.
.TP
.BI "--or-mask " "mask"
Perform bitwise `or' on the IP address and this mask.
.P
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:
.IP
tc filter add dev eth3 parent 1:0 protocol ip fw
.P
Earlier we had many rules just like below:
.IP
iptables -t mangle -A POSTROUTING -o eth3 -d 192.168.5.2 -j MARK
--set-mark 0x10502
.IP
iptables -t mangle -A POSTROUTING -o eth3 -d 192.168.5.3 -j MARK
--set-mark 0x10503
.P
Using IPMARK target we can replace all the mangle/mark rules with only one:
.IP
iptables -t mangle -A POSTROUTING -o eth3 -j IPMARK --addr=dst
--and-mask=0xffff --or-mask=0x10000
.P
On the routers with hundreds of users there should be significant load
decrease (e.g. twice).