From: Jakub Kicinski <kuba@kernel.org>
To: wenxu@ucloud.cn
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net] ip_tunnel: fix over-mtu packet send fail without TUNNEL_DONT_FRAGMENT flags
Date: Fri, 23 Oct 2020 14:12:54 -0700 [thread overview]
Message-ID: <20201023141254.7102795d@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> (raw)
In-Reply-To: <1603272115-25351-1-git-send-email-wenxu@ucloud.cn>
On Wed, 21 Oct 2020 17:21:55 +0800 wenxu@ucloud.cn wrote:
> From: wenxu <wenxu@ucloud.cn>
>
> The TUNNEL_DONT_FRAGMENT flags specific the tunnel outer ip can do
> fragment or not in the md mode. Without the TUNNEL_DONT_FRAGMENT
> should always do fragment. So it should not care the frag_off in
> inner ip.
Can you describe the use case better? My understanding is that we
should propagate DF in normally functioning networks, and let PMTU
do its job.
> Fixes: cfc7381b3002 ("ip_tunnel: add collect_md mode to IPIP tunnel")
> Signed-off-by: wenxu <wenxu@ucloud.cn>
> ---
> net/ipv4/ip_tunnel.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
> index 8b04d1d..ee65c92 100644
> --- a/net/ipv4/ip_tunnel.c
> +++ b/net/ipv4/ip_tunnel.c
> @@ -608,9 +608,6 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
> ttl = ip4_dst_hoplimit(&rt->dst);
> }
>
> - if (!df && skb->protocol == htons(ETH_P_IP))
> - df = inner_iph->frag_off & htons(IP_DF);
> -
> headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
> if (headroom > dev->needed_headroom)
> dev->needed_headroom = headroom;
next prev parent reply other threads:[~2020-10-23 21:12 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 9:21 [PATCH net] ip_tunnel: fix over-mtu packet send fail without TUNNEL_DONT_FRAGMENT flags wenxu
2020-10-23 21:12 ` Jakub Kicinski [this message]
2020-10-26 8:23 ` wenxu
2020-10-26 20:56 ` Jakub Kicinski
2020-10-27 14:51 ` David Ahern
2020-10-27 15:55 ` Jakub Kicinski
2020-10-29 2:30 ` wenxu
2020-10-30 1:14 ` Jakub Kicinski
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