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From: Ben Greear <greearb@candelatech.com>
To: Seong Moon <seong@etri.re.kr>
Cc: netdev@oss.sgi.com
Subject: Re: dev->hard_header ?
Date: Tue, 19 Nov 2002 21:06:01 -0800	[thread overview]
Message-ID: <3DDB1839.4020909@candelatech.com> (raw)
In-Reply-To: 005201c2903f$37e88580$21abfe81@seong

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

      reply	other threads:[~2002-11-20  5:06 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-11-20  2:46 dev->hard_header ? Seong Moon
2002-11-20  5:06 ` Ben Greear [this message]

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