[Click] help: for the userlevel tohost

[Huiqing Fu]

hi,
I am trying to read packets from device eth0 to fake0 device, and add some
delay to the packets.
But, now the server can not get the packets from kernel, I guess maybe the
tohost fails returning the packets or the kernel drops the packets.
Can anyone help me to deal the problem?
My target is that:client send packets to eth0, but server listen to fake0.
So the click should read the packets from eth0 and change the packets then
return them to kernel, so that server
can get the packets.
The codes are below:

// fromhost-tunnel.click



// This configuration demonstrates the use of FromHost, by tunneling all

// packets for TEST_NETWORK via the kernel Click configuration. To adapt

// for your own use, change the AddressInfo element and replace device

// "eth0" with your relevant device.



AddressInfo(

        // The address of a machine and a network segment.

        // This machine will route packets for the network via FromHost,

        // using the host address as source.

        TEST_NETWORK 192.168.2.3/24,

        TEST_MAC 1e:b2:02:2f:6a:0c,



        // This host's real address.

        MY_ADDR 192.168.1.1,



        // The gateway machine this host really uses to send to
TEST_NETWORK.

        MY_GATEWAY 192.150.187.1)



elementclass FixChecksums {

    // fix the IP checksum, and any embedded checksums that include data

    // from the IP header (TCP and UDP in particular)

    input -> SetIPChecksum

        -> ipc :: IPClassifier(tcp, udp, -)

        -> SetTCPChecksum

        -> output;

    ipc[1] -> SetUDPChecksum -> output;

    ipc[2] -> output

}



th :: ToHost(fake0);



FromHost(fake0, TEST_NETWORK, ETHER TEST_MAC)

        // Respond to ARP requests

        -> fh_cl :: Classifier(12/0806, 12/0800)

        -> ARPResponder(0/0 1:1:1:1:1:1)

        ->Print(fharp,60)

        -> th



// Forward IP packets from the fake device to the real Internet

fh_cl[1] -> Strip(14)                           // remove crap Ether header

         ->Print(fhip,60)

         -> MarkIPHeader(0)

        -> StoreIPAddress(MY_ADDR, 12)          // store real address as
source

        -> FixChecksums                         // recalculate checksum

        -> SetIPAddress(MY_GATEWAY)             // route via gateway

        ->Print(iparpq)

        -> aq :: ARPQuerier(MY_ADDR, eth0)

        -> Queue

        -> ToDevice(eth0)



// listen for ARP responses

fd :: FromDevice(eth0,SNIFFER false)

        -> fd_cl :: Classifier(12/0806 20/0002, 12/0800, -)

        ->Print(fdeth0arpr,60)

        -> t::Tee

        -> Print(arpq)

         -> [1]aq;

         t[1]

             ->Print(arpdup)

              -> th             // ARP responses to us and host

fd_cl[2]

       -> Print(fdeth0other,60)

        -> th





// Packets arriving from the Internet from the test network must have their

// destination addresses changed, to our fake address

fd_cl[1] -> CheckIPHeader(14)

        // check for responses from the test network

        -> ipc :: IPClassifier(udp port 5500, -)

        ->Print(fdeth0ip,60)

        // replace the real destination address with the fake address

        ->StoreEtherAddress(TEST_MAC,0)

        -> StoreIPAddress(TEST_NETWORK, 30)

        -> FixChecksums

        ->Print(udpdstfake,60)

        -> th

ipc[1]

        ->CheckIPHeader(14)

        // check for responses from the test network

        ->Print(otherip,60)

        // replace the real destination address with the fake address

        ->StoreEtherAddress(TEST_MAC,0)

        -> StoreIPAddress(TEST_NETWORK, 30)

        -> FixChecksums

        ->CheckIPHeader(14)

        ->Print(dstfake,60)

        -> th


Thank you.

Huiqing Fu