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From:   Praveen Chaudhary <praveen5582@gmail.com>
To:     fw@strlen.de
Cc:     astracner@linkedin.com, davem@davemloft.net, kadlec@netfilter.org,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        pablo@netfilter.org, praveen5582@gmail.com, zxu@linkedin.com
Subject: RE: [PATCH] [netfilter]: Fix skb->csum calculation when netfilter
Date:   Wed, 23 Oct 2019 13:56:02 -0700
Message-Id: <1571864162-9097-1-git-send-email-pchaudhary@linkedin.com>
In-Reply-To: <20191023193337.GP25052@breakpoint.cc>
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Hi Florian 

Thanks for the review,

inet_proto_csum_replace16 is called from many places, whereas this fix is applicable only for nf_nat_ipv6_csum_update, where we need to update skb->csum for ipv6 src/dst address change. 
Also my point is, inet_proto_csum_replace16 is updating skb->csum for change in udp header checksum field, but that is not complete. So, I added a new function. Basically, I used a safe apprioach to fix it, without impacting other cases. Let me know other options,  I am open to suggestions.

More importantly, I hope this is clear that the current code does not update skb->csum completely. Which is a bug. Thanks again.