How to account traffic in IPTABLES?

[Bobo <boboaq@xxxxxxx>]

 HI

      I use the iptables + squid as the gateway of one LAN,and it is very good in fact.

   Now,I would like to get the traffic accounting of each IP of the LAN.

  How to get these data ? Does IPtables contain these data?

  Are there some tools for traffic accounting of iptables?

  I could use perl and shell programing.Could I analyze the log file of iptables to account?

  Thanks