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2007/4/20, Nathan Smith <ndansmith@×××××.com>: |
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> |
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> The symptoms (broken TCP traffic to some sites) |
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> depend entirely upon the sites you are connecting to and how your |
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> connections are routed. |
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We saw that affected users are sending TCP data with bad checksum |
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(this could apply to udp and/or icmp too? anyone to check?). |
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Then, some router on the Internet can decide to drop such bad packet. I |
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noticed Linux doesn't drop but Checkpoint does. |
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Another point, note that the bad checksum is always good_checksum+0100 |
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""" |
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[bad tcp cksum 3de5 (->3ce5)!] |
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[bad tcp cksum 322d (->312d)!] |
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[bad tcp cksum 25ad (->24ad)!] |
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""" |
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I guess this is the checksum algorithm that is incompatible with -O2. Even |
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if I won't check the source code :p |
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However, using tcpdump I can tell that some machines apparently do not |
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> experience this problem, so it may be processor-specific (which makes |
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> sense given that it is an optimization problem). I use a Pentium M. |
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> What are other people using that have been affected by the problem? |
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Mine is pentium-4 |
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|
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-- |
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Camille Huot |
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