From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: David Ahern <dsahern@kernel.org>
Cc: Networking <netdev@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"john fastabend" <john.fastabend@gmail.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Martin Lau" <kafai@fb.com>, "Song Liu" <songliubraving@fb.com>,
"Yonghong Song" <yhs@fb.com>, "Andrii Nakryiko" <andriin@fb.com>,
"David Ahern" <dsahern@gmail.com>
Subject: Re: [PATCH v2 bpf-next 2/5] bpf: Add support to attach bpf program to a devmap entry
Date: Thu, 28 May 2020 00:01:40 -0700 [thread overview]
Message-ID: <CAEf4BzYZSPdGH+RXp+kHfWnGGLRuiP=ho9oMsSf7RsYWyeNk0g@mail.gmail.com> (raw)
In-Reply-To: <20200528001423.58575-3-dsahern@kernel.org>
On Wed, May 27, 2020 at 5:17 PM David Ahern <dsahern@kernel.org> wrote:
>
> From: David Ahern <dsahern@gmail.com>
>
> Add BPF_XDP_DEVMAP attach type for use with programs associated with a
> DEVMAP entry.
>
> Allow DEVMAPs to associate a program with a device entry by adding
> a bpf_prog_fd to 'struct devmap_val'. Values read show the program
> id, so the fd and id are a union.
>
> The program associated with the fd must have type XDP with expected
> attach type BPF_XDP_DEVMAP. When a program is associated with a device
> index, the program is run on an XDP_REDIRECT and before the buffer is
> added to the per-cpu queue. At this point rxq data is still valid; the
> next patch adds tx device information allowing the prorgam to see both
> ingress and egress device indices.
>
> XDP generic is skb based and XDP programs do not work with skb's. Block
> the use case by walking maps used by a program that is to be attached
> via xdpgeneric and fail if any of them are DEVMAP / DEVMAP_HASH with
> > 4-byte values.
>
> Block attach of BPF_XDP_DEVMAP programs to devices.
>
> Signed-off-by: David Ahern <dsahern@gmail.com>
> ---
Please cc bpf@vger.kernel.org in the future for patches related to BPF
in general.
> include/linux/bpf.h | 5 +++
> include/uapi/linux/bpf.h | 5 +++
> kernel/bpf/devmap.c | 79 +++++++++++++++++++++++++++++++++-
> net/core/dev.c | 18 ++++++++
> tools/include/uapi/linux/bpf.h | 5 +++
> 5 files changed, 110 insertions(+), 2 deletions(-)
>
[...]
>
> +static struct xdp_buff *dev_map_run_prog(struct net_device *dev,
> + struct xdp_buff *xdp,
> + struct bpf_prog *xdp_prog)
> +{
> + u32 act;
> +
> + act = bpf_prog_run_xdp(xdp_prog, xdp);
> + switch (act) {
> + case XDP_DROP:
> + fallthrough;
nit: I don't think fallthrough is necessary for cases like:
case XDP_DROP:
case XDP_PASS:
/* do something */
> + case XDP_PASS:
> + break;
> + default:
> + bpf_warn_invalid_xdp_action(act);
> + fallthrough;
> + case XDP_ABORTED:
> + trace_xdp_exception(dev, xdp_prog, act);
> + act = XDP_DROP;
> + break;
> + }
> +
> + if (act == XDP_DROP) {
> + xdp_return_buff(xdp);
> + xdp = NULL;
hm.. if you move XDP_DROP case to after XDP_ABORTED and do fallthrough
from XDP_ABORTED, you won't even need to override act and it will just
handle all the cases, no?
switch (act) {
case XDP_PASS:
return xdp;
default:
bpf_warn_invalid_xdp_action(act);
fallthrough;
case XDP_ABORTED:
trace_xdp_exception(dev, xdp_prog, act);
fallthrough;
case XDP_DROP:
xdp_return_buff(xdp);
return NULL;
}
Wouldn't this be simpler?
> + }
> +
> + return xdp;
> +}
> +
[...]
next prev parent reply other threads:[~2020-05-28 7:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-28 0:14 [PATCH v2 bpf-next 0/5] bpf: Add support for XDP programs in DEVMAP entries David Ahern
2020-05-28 0:14 ` [PATCH v2 bpf-next 1/5] devmap: Formalize map value as a named struct David Ahern
2020-05-28 7:01 ` Andrii Nakryiko
2020-05-28 22:37 ` David Ahern
2020-05-28 0:14 ` [PATCH v2 bpf-next 2/5] bpf: Add support to attach bpf program to a devmap entry David Ahern
2020-05-28 7:01 ` Andrii Nakryiko [this message]
2020-05-28 22:40 ` David Ahern
2020-05-28 22:54 ` Andrii Nakryiko
2020-05-28 8:54 ` Toke Høiland-Jørgensen
2020-05-28 0:14 ` [PATCH v2 bpf-next 3/5] xdp: Add xdp_txq_info to xdp_buff David Ahern
2020-05-28 0:14 ` [PATCH v2 bpf-next 4/5] libbpf: Add SEC name for xdp programs attached to device map David Ahern
2020-05-28 7:04 ` Andrii Nakryiko
2020-05-28 22:49 ` David Ahern
2020-05-28 0:14 ` [PATCH v2 bpf-next 5/5] selftest: Add tests for XDP programs in devmap entries David Ahern
2020-05-28 7:08 ` Andrii Nakryiko
2020-05-28 10:25 ` Jesper Dangaard Brouer
2020-05-28 22:56 ` David Ahern
2020-05-28 22:54 ` David Ahern
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