netdev - Re: [PATCH net-next 2/3] bpf: allow disabling tunnel csum for ipv6

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Message-ID: <9e6df44e-380e-4d32-51bc-eb45df5687e4@iogearbox.net>
Date:   Mon, 4 Dec 2017 09:33:31 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     William Tu <u9012063@...il.com>, netdev@...r.kernel.org
Subject: Re: [PATCH net-next 2/3] bpf: allow disabling tunnel csum for ipv6

Hi William,

On 12/02/2017 12:26 AM, William Tu wrote:
> Before the patch, BPF_F_ZERO_CSUM_TX can be used only for ipv4 tunnel.
> With introduction of ip6gretap collect_md mode, the flag should be also
> supported for ipv6.
> 
> Signed-off-by: William Tu <u9012063@...il.com>
> Cc: Daniel Borkmann <daniel@...earbox.net>
> ---
>  net/core/filter.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 6a85e67fafce..8ec5a504eb28 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -3026,10 +3026,11 @@ BPF_CALL_4(bpf_skb_set_tunnel_key, struct sk_buff *, skb,
>  				  IPV6_FLOWLABEL_MASK;
>  	} else {
>  		info->key.u.ipv4.dst = cpu_to_be32(from->remote_ipv4);
> -		if (flags & BPF_F_ZERO_CSUM_TX)
> -			info->key.tun_flags &= ~TUNNEL_CSUM;
>  	}
>  
> +	if (flags & BPF_F_ZERO_CSUM_TX)
> +		info->key.tun_flags &= ~TUNNEL_CSUM;
> +

Looks fine to me. One minor request from my side:

Could you move the check right below the 'flags & BPF_F_DONT_FRAGMENT'
test in bpf_skb_set_tunnel_key(), so common tun_flags handling is
logically together. With that change done, please add my ack:

Acked-by: Daniel Borkmann <daniel@...earbox.net>

Thanks,
Daniel