netdev - Re: [PATCH net] net: Clear local_df only if crossing namespace.

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Message-ID: <20140207222840.GD16198@order.stressinduktion.org>
Date:	Fri, 7 Feb 2014 23:28:40 +0100
From:	Hannes Frederic Sowa <hannes@...essinduktion.org>
To:	Pravin <pshelar@...ira.com>
Cc:	davem@...emloft.net, netdev@...r.kernel.org,
	"Templin, Fred L" <Fred.L.Templin@...ing.com>
Subject: Re: [PATCH net] net: Clear local_df only if crossing namespace.

Hi!

On Fri, Feb 07, 2014 at 02:12:38PM -0800, Pravin wrote:
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -3905,12 +3905,13 @@ EXPORT_SYMBOL(skb_try_coalesce);
>   */
>  void skb_scrub_packet(struct sk_buff *skb, bool xnet)
>  {
> -	if (xnet)
> +	if (xnet) {
>  		skb_orphan(skb);
> +		skb->local_df = 0;
> +	}
>  	skb->tstamp.tv64 = 0;
>  	skb->pkt_type = PACKET_HOST;
>  	skb->skb_iif = 0;
> -	skb->local_df = 0;
>  	skb_dst_drop(skb);
>  	skb->mark = 0;
>  	secpath_reset(skb);

I wonder if this should be the right behaviour for tunnels, which should just
do fragmentation based on IP_DF, even if the packet originated locally from a
socket which allowed local fragmentation (inet->pmtudisc < IP_PMTUDISC_DO).

Greetings,

  Hannes

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