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From:   William Tu <u9012063@gmail.com>
Date:   Fri, 22 Apr 2022 09:25:53 -0700
Message-ID: <CALDO+SZNeBrupoCigpM9g5TEGAgEi6k8+usXc0O8RqkLmeO99Q@mail.gmail.com>
Subject: Re: [PATCH net 2/3] ip6_gre: Make o_seqno start from 0 in native mode
To:     Peilin Ye <yepeilin.cs@gmail.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Peilin Ye <peilin.ye@bytedance.com>,
        "xeb@mail.ru" <xeb@mail.ru>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Cong Wang <cong.wang@bytedance.com>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>
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On Thu, Apr 21, 2022 at 3:08 PM Peilin Ye <yepeilin.cs@gmail.com> wrote:
>
> From: Peilin Ye <peilin.ye@bytedance.com>
>
> For IP6GRE and IP6GRETAP devices, currently o_seqno starts from 1 in
> native mode.  According to RFC 2890 2.2., "The first datagram is sent
> with a sequence number of 0."  Fix it.
>
> It is worth mentioning that o_seqno already starts from 0 in collect_md
> mode, see the "if (tunnel->parms.collect_md)" clause in __gre6_xmit(),
> where tunnel->o_seqno is passed to gre_build_header() before getting
> incremented.
>
> Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
> Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>

LGTM
Acked-by: William Tu <u9012063@gmail.com>