Re: pskb_copy() in tcp_transmit_skb()

Hi,

On Tuesday 13 September 2011 wrote Gaofeng:

quoted

I'm trying to understand the reason for the possible call to pskb_copy()
in tcp_transmit_skb().
I don't find, where we may have a cloned skb entering tcp_transmit_skb().

The original pskb_copy() came from tcp_retransmit_skb() (commit
dfb4b9dceb35c567a595ae5e9d035cfda044a103).
But from that point, the git-history does not show where the pskb_copy()
is coming from.


Does somebody has an idea, how a cloned skb can be passed to
tcp_transmit_skb() and thus trigger this call to pskb_copy().

maybe nat,nat can change the tcp packet header

although NAT may change the TCP header, it is not doing an skb_clone() - (at 
least I don't find it).
Thus, we will not call pskb_copy() in tcp_transmit_skb() due to NAT.

Christoph

--
Christoph Paasch
PhD Student

IP Networking Lab --- http://inl.info.ucl.ac.be
MultiPath TCP in the Linux Kernel --- http://inl.info.ucl.ac.be/mptcp
Université Catholique de Louvain

www.rollerbulls.be
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