tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 \ match ip src 1.2.3.4 match tcp dst 80 0xffff flowid 1:10in the above command i would like to know what does the string "0xffff" stand for, i know it is explained in adv. routing howto's u32 section; but i could not make any heads or tails of it. can some explain in detail any links would also do.