[Click] Problems using Click

[John Bicket]

I think I understand that you want click to route packets from eth0
on the 10.0.0.X network.

Your probably want to do this instead of what you configuration does:

1. run ifconfig eth0 up, but don't give it an ip address. Otherwise linux
will handle the routing and arp, and if I understand you correctly you
want userlevel click to handle this stuff.
2. Use tun :: KernelTun(10.0.0.1/24). Linux will add the route to
10.0.0.X through the tun0 brought up by kerneltun. Now you have
to send packets destined to 10.0.0.1 in your configuration to the "tun"
element, otherwise the kernel will not get them.

--john

Juli?n David  Morillo Pozo [jmorillo at ac.upc.edu] wrote:
>Sorry, there was a mistake on the previous message: the IP address of the 
>client machine is 10.0.0.1 and not 10.0.0.4. 
>
>El Jueves, 3 de Febrero de 2005 16:21, Juli?n David Morillo Pozo escribi?:
>> Hello,
>>
>> We are trying to comunicate two machines using user level CLICK, but some
>> strange things are happening. We are using two directly connected machines
>> that have flat IP addresses (10.0.0.1/32 and 10.0.0.4/32) and that act both
>> as a router and as a host. In order to allow this behaviour, we are using
>> the KernelTun element and every packet generated by the machine is routed
>> to the tun0 device created by this element (this is the only route we have
>> in the kernel forwarding table of both machines).
>>
>> We are able to ping from one machine to the other but we can not establish
>> a tcp connection (ftp, ssh) between them. By executing tcpdump on the
>> client machine (10.0.0.4/32) we have got the following:
>>
>> tcpdump: listening on eth0
>> 15:34:58.439506 10.0.0.1.35284 > 10.0.0.4.ftp: S 2110020349:2110020349(0)
>> win 6024 <mss 2008,sackOK,timestamp 590699432 0,nop,wscale 1> (DF)
>> 15:34:58.439774 10.0.0.4.ftp > 10.0.0.1.35284: S 2069372027:2069372027(0)
>> ack 2110020350 win 5988 <mss 2008,sackOK,timestamp 619677506
>> 590699432,nop,wscale 0> (DF)
>> 15:34:58.439948 10.0.0.1.35284 > 10.0.0.4.ftp: R 2110020350:2110020350(0)
>> win 0 (DF)
>>
>> And at the same time, click shows the following error messages:
>>
>> LinearIPLookup: no gw for 3205393
>> LinearIPLookup: no gw for 4215393
>>
>> Everything works fine if we use regular kernel forwarding in the client
>> machine (10.0.0.4/32).
>>
>> The CLICK configuration we are using in the client is the following (in the
>> server, the configuration is the same, just changing IP addresses):
>>
>> ============================================================
>> // Shared IP input path and routing table
>> _xorp_ip :: Strip(14)
>>     -> CheckIPHeader(INTERFACES 10.0.0.1/32)
>>     -> _xorp_rt :: LinearIPLookup(10.0.0.1/32 1, 10.0.0.4/32 0);
>>
>> elementclass FixChecksums {
>>     input -> SetIPChecksum
>>           -> ipc :: IPClassifier(tcp, udp, -)
>>           -> SetTCPChecksum
>>           -> output;
>>     ipc[1] -> SetUDPChecksum -> output;
>>     ipc[2] -> output
>> }
>>
>> tun :: KernelTun(172.16.0.1/24) -> Paint(0) -> _xorp_rt;
>>
>>
>> // ARP responses are copied to each ARPQuerier and the host.
>> _xorp_arpt :: Tee(2);
>>
>> // Input and output paths for eth0
>> _xorp_c0 :: Classifier(12/0806 20/0001, 12/0806 20/0002, 12/0800, -);
>> FromDevice(eth0) -> _xorp_c0;
>> _xorp_out0 :: Queue(200) -> _xorp_to_device0 :: ToDevice(eth0);
>> _xorp_c0[0] -> _xorp_ar0 :: ARPResponder(10.0.0.1 00:0C:6E:F2:9B:6E) ->
>> _xorp_out0;
>> _xorp_arpq0 :: ARPQuerier(10.0.0.1, 00:0C:6E:F2:9B:6E) -> _xorp_out0;
>> _xorp_c0[1] -> _xorp_arpt;
>> _xorp_arpt[0] -> [1]_xorp_arpq0;
>> _xorp_c0[2] -> Paint(1) -> _xorp_ip;
>> _xorp_c0[3] -> Print("eth0 non-IP") -> Discard;
>>
>> // Local delivery
>> _xorp_arpt[1] -> Discard;
>> _xorp_rt[1] -> Discard;
>>
>> // Forwarding path for eth0
>> _xorp_rt[0] -> DropBroadcasts -> _xorp_sw0 :: PaintSwitch();
>> _xorp_gio0 :: IPGWOptions(10.0.0.1)
>>     -> FixIPSrc(10.0.0.1)
>>     -> _xorp_dt0 :: DecIPTTL
>>     -> _xorp_fr0 :: IPFragmenter(1500)
>>     -> [0]_xorp_arpq0;
>>
>> _xorp_sw0[0] -> StoreIPAddress(10.0.0.1,12) -> FixChecksums -> _xorp_fr0;
>> _xorp_sw0[1] -> _xorp_cp0 :: Tee(2) -> ICMPError(10.0.0.1, redirect, host)
>> -> _xorp_rt;
>> _xorp_cp0[1] -> _xorp_gio0
>> _xorp_dt0[1] -> ICMPError(10.0.0.1, timeexceeded) -> _xorp_rt;
>> _xorp_fr0[1] -> ICMPError(10.0.0.1, unreachable, needfrag) -> _xorp_rt;
>> _xorp_gio0[1] -> ICMPError(10.0.0.1, parameterproblem) -> _xorp_rt;
>> ==============================================================
>>
>> Does anybody know what is the problem?
>>
>> Cheers,
>
>-- 
>=============================================
>Juli?n David Morillo Pozo
>PhD Student - Computer Networking Group
>Department of Computer Architecture   (DAC)
>Polytechnical University of Catalonia (UPC)
>Phone: +34-934017182   Fax: +34-934017055
>URL: http://people.ac.upc.edu/jmorillo
>=============================================
>
>
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