[Click] package reordering - ATM:IP reassembly

[Beyers Cronje]

Hi Koen,

-reorder these packages in increasing time. Also, for every package:
> wait at least 30ms to see if a package with an earlier timestamp
> arrives.
> ->> tis is my first problem: i don't know how to start solving this ...


You could create your own queue  that  does in-order queueing and then use
something like DelayUnqueue
http://www.read.cs.ucla.edu/click/elements/delayunqueue to unqueue every
30ms.

-when packages a reordered, i need to reassemble the IP packets
> contained in the ATM cells (1 ip packet is spread out over more than
> one atm cell). Here i have to group the ATM cells folowing the
> VPI/VCI-numbers and wait until i have a full IP packet (or timeout
> after some seconds).
> This problem is somewhat like reassembling fragmented IP packets: wait
> until all packets from some 'connection' have arrived and then
> reassemble them.
> ->> this is my second problem: how should i keep track of all the
> current connections, temporarily storing incomplete packets?


Most elements that keep state of flows make use of Click's hashmap. Have a
look  at  TCPRewriter , SnoopTcp or any other element that keeps state.

Beyers