From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
To: Jakub Kicinski <kuba@kernel.org>,
Oliver Herms <oliver.peter.herms@gmail.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net,
kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org
Subject: Re: [PATCH v3] IPv4: Tunnel: Fix effective path mtu calculation
Date: Tue, 30 Jun 2020 17:51:41 +0200 [thread overview]
Message-ID: <99564f5c-07e4-df0d-893d-40757a0f2167@6wind.com> (raw)
In-Reply-To: <20200629232235.6047a9c1@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Le 30/06/2020 à 08:22, Jakub Kicinski a écrit :
[snip]
> My understanding is that for a while now tunnels are not supposed to use
> dev->hard_header_len to reserve skb space, and use dev->needed_headroom,
> instead. sit uses hard_header_len and doesn't even copy needed_headroom
> of the lower device.
I missed this. I was wondering why IPv6 tunnels uses hard_header_len, if there
was a "good" reason:
$ git grep "hard_header_len.*=" net/ipv6/
net/ipv6/ip6_tunnel.c: dev->hard_header_len =
tdev->hard_header_len + t_hlen;
net/ipv6/ip6_tunnel.c: dev->hard_header_len = LL_MAX_HEADER + t_hlen;
net/ipv6/sit.c: dev->hard_header_len = tdev->hard_header_len +
sizeof(struct iphdr);
net/ipv6/sit.c: dev->hard_header_len = LL_MAX_HEADER + t_hlen;
A cleanup would be nice ;-)
next prev parent reply other threads:[~2020-06-30 15:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-25 22:44 [PATCH v3] IPv4: Tunnel: Fix effective path mtu calculation Oliver Herms
2020-06-30 6:22 ` Jakub Kicinski
2020-06-30 10:21 ` Oliver Herms
2020-06-30 17:27 ` Jakub Kicinski
2020-06-30 15:51 ` Nicolas Dichtel [this message]
2020-06-30 17:33 ` Jakub Kicinski
2020-06-30 22:27 ` Nicolas Dichtel
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