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From: Christian Perle <christian.perle@secunet.com>
To: Florian Westphal <fw@strlen.de>
Cc: <netdev@vger.kernel.org>, <steffen.klassert@secunet.com>,
	<netfilter-devel@vger.kernel.org>
Subject: Re: [PATCH net 3/3] net: ip: always refragment ip defragmented packets
Date: Thu, 7 Jan 2021 08:52:50 +0100	[thread overview]
Message-ID: <20210107075250.GA16010@cell> (raw)
In-Reply-To: <20210105231523.622-4-fw@strlen.de>

Hello Florian,

On Wed, Jan 06, 2021 at 00:15:23 +0100, Florian Westphal wrote:

> Force refragmentation as per original sizes unconditionally so ip tunnel
> will encapsulate the fragments instead.
[...]
> diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
> index 89fff5f59eea..2ed0b01f72f0 100644
> --- a/net/ipv4/ip_output.c
> +++ b/net/ipv4/ip_output.c
> @@ -302,7 +302,7 @@ static int __ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *
>  	if (skb_is_gso(skb))
>  		return ip_finish_output_gso(net, sk, skb, mtu);
>  
> -	if (skb->len > mtu || (IPCB(skb)->flags & IPSKB_FRAG_PMTU))
> +	if (skb->len > mtu || IPCB(skb)->frag_max_size)
>  		return ip_fragment(net, sk, skb, mtu, ip_finish_output2);
>  
>  	return ip_finish_output2(net, sk, skb);
> -- 
> 2.26.2

Did some tests yesterday and I can confirm that this patch fixes the
problem for both IPIP tunnel and XFRM tunnel interfaces.

Thanks for the fix!
  Christian Perle
-- 
Christian Perle
Senior Berater / Senior Consultant
Netzwerk- und Client-Sicherheit / Network & Client Security
Öffentliche Auftraggeber / Public Authorities
secunet Security Networks AG

Tel.: +49 201 54 54-3533, Fax: +49 201 54 54-1323
E-Mail: christian.perle@secunet.com
Ammonstraße 74, 01067 Dresden, Deutschland
www.secunet.com

secunet Security Networks AG
Sitz: Kurfürstenstraße 58, 45138 Essen, Deutschland
Amtsgericht Essen HRB 13615
Vorstand: Axel Deininger (Vors.), Torsten Henn, Dr. Kai Martius, Thomas Pleines
Aufsichtsratsvorsitzender: Ralf Wintergerst

  reply	other threads:[~2021-01-07  7:54 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-05 12:12 BUG: IPv4 conntrack reassembles forwarded packets Christian Perle
2021-01-05 12:12 ` Christian Perle
2021-01-05 23:15 ` [PATCH net 0/3] net: fix netfilter defrag/ip tunnel pmtu blackhole Florian Westphal
2021-01-05 23:15   ` [PATCH net 1/3] selftests: netfilter: add selftest for ipip pmtu discovery with enabled connection tracking Florian Westphal
2021-01-05 23:15   ` [PATCH net 2/3] net: fix pmtu check in nopmtudisc mode Florian Westphal
2021-01-05 23:15   ` [PATCH net 3/3] net: ip: always refragment ip defragmented packets Florian Westphal
2021-01-07  7:52     ` Christian Perle [this message]
2021-01-07 22:14   ` [PATCH net 0/3] net: fix netfilter defrag/ip tunnel pmtu blackhole Pablo Neira Ayuso
2021-01-07 22:45     ` Jakub Kicinski

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