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Re: dev->hard_header ?

To: Seong Moon <seong@xxxxxxxxxx>
Subject: Re: dev->hard_header ?
From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Date: Tue, 19 Nov 2002 21:06:01 -0800
Cc: netdev@xxxxxxxxxxx
Organization: Candela Technologies
References: <005201c2903f$37e88580$21abfe81@seong>
Sender: netdev-bounce@xxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2a) Gecko/20020910
Seong Moon wrote:
In Layer 3 Protocols(eg. IP, IPv6, ...),
they calls dev_queue_xmit() to send their data.

Before calling dev_queue_xmit(),
does the layer 3 protocols always call dev->hard_header ?

Actually, I'm not sure when dev->hard_header is called.

I think dev->hard_start_xmit can include the part of dev->hard_header.
Why did the developer seperate the header building and sending frame
fucntion ?

It's not always called, this way user-space (or other parts of the kernel)
can build the headers if desired.  This at least works for ethernet and
VLAN interfaces.

Ben


thanks in advance.



--
Ben Greear <greearb@xxxxxxxxxxxxxxx>       <Ben_Greear AT excite.com>
President of Candela Technologies Inc      http://www.candelatech.com
ScryMUD:  http://scry.wanfear.com     http://scry.wanfear.com/~greear



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