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From: phill whelan <kernel@exis.cl>
To: linux-kernel@vger.kernel.org
Subject: NF_ARP_OUT skb has NULL link layer header
Date: Wed, 23 Jun 2004 13:38:19 -0400	[thread overview]
Message-ID: <20040623133819.571db2e7.kernel@exis.cl> (raw)

Hello,

I've been working lately on a netfilter hook extension which rewrites outgoing ARP packets to spoof a host's MAC address.

I've succesfully spoofed ARP replies, but have seen that several OS's tend to update their arp cache based on information in ARP requests.
After several panic()'s, I noticed that the link layer header (skb->mac)
is NULL. My intention was to rewrite the ethernet mac address to the spoofed MAC address.

Is there a way to rewrite the link layer header besides modifying skb->mac (skb->mac.ethernet to be precise), or could I possibly just tag on a kmalloc()'ed pointer to the skb->mac?

If it makes any difference, I only noticed this when porting the code to linux 2.6 (2.6.7).

Thanks a lot, in advance

Phillip Whelan
EXIS (http://www.exis.cl)

             reply	other threads:[~2004-06-23 17:42 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-06-23 17:38 phill whelan [this message]
  -- strict thread matches above, loose matches on Subject: below --
2004-06-23 14:07 NF_ARP_OUT skb has NULL link layer header kernel exis

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