[Click] IP header check failed:

[Eddie Kohler]

Hi,

The packet has a length of 1498 but the dump has captured less than the 
complete length.  As you can see from your print statements, only 68 bytes 
were captured.  CheckIPHeader expects complete IP packets; it can't check the 
length or checksum of incomplete packets.

Eddie


Latency Buster wrote:
> I am trying to separate out multicast packets. Before feeding to the
> IPClassifier, when I pass it through CheckIPHeader(), I recv lots of
> IP HEader Failed Messages. The input packets are multicast packets but
> the IP header is clean (as looked via wireshark). Any insights why
> this might occur?
> 
> 
> 
> ------------------ CONFIG ---------------------------------------
> inputDevice::FromDump(/home/click/test.pcap, END_AFTER 0.2);
> 
> inputDevice->c0::Classifier (12/8100 /* dot1Q */,      12/0800 /*
> 'normal ip packets */,   - /* everything else including ARP */);
> 
> // Filter out multicast packets
> ip_classifier::IPClassifier(224.0.0.0/4 and ip proto udp, - /*
> everything else */);
> 
> 
> c0[0]-> Print("We received 802.1Q Packets.. Discarding") -> Discard;
> c0[1]->   ip::CheckIPHeader (14, INTERFACES 224.0.0.0/4,  VERBOSE
> true,CHECKSUM false);
> c0[2]-> Discard;
> 
> ip[0] -> ip_classifier;
> ip[1] -> Print("IP header Failed..", 20) -> ToDump (/home/click/badip.pcap);
> 
> ip_classifier[0]->Print("These are valid Multicast Packets for NAT") -> Discard;
> ip_classifier[1]->Print ("This will all go to LINUX Host")-> Discard;
> 
> ----------------------------- END OF CONFIG --------------------------
> 
> click-user:~/ click test_mcast.click
> 
> IP header Failed..:   68 |  01005e43 0d0d001b 0ded1180 08004500
> 05da3e82 00001c11 337fac15 7e2cefc3 0d0dbb60 138905c6 364d0000
> 04534b07 0d32000f 30490000 00000000 00010000 13890000
> 
> IP header Failed..:   68 |01005e43 0d0d001b 0ded1180 08004500 05da3e83
> 00001c11 337eac15 7e2cefc3 0d0dbb60 138905c6 4ccb0000 04544b07
> 0d330000 19d80000 00000000 00010000 13890000
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