From: Menglong Dong <menglong8.dong@gmail.com>
To: andrii@kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev,
song@kernel.org, yonghong.song@linux.dev,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, davem@davemloft.net,
edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
mykolal@fb.com, shuah@kernel.org, horms@kernel.org,
dhowells@redhat.com, linyunsheng@huawei.com,
aleksander.lobakin@intel.com, joannelkoong@gmail.com,
laoar.shao@gmail.com, kuifeng@meta.com, menglong8.dong@gmail.com,
bjorn@rivosinc.com, linux-kernel@vger.kernel.org,
bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: [PATCH bpf-next 0/2] bpf: add csum/ip_summed fields to __sk_buff
Date: Fri, 29 Dec 2023 16:14:07 +0800 [thread overview]
Message-ID: <20231229081409.1276386-1-menglong8.dong@gmail.com> (raw)
For now, we have to call some helpers when we need to update the csum,
such as bpf_l4_csum_replace, bpf_l3_csum_replace, etc. These helpers are
not inlined, which causes poor performance.
In fact, we can define our own csum update functions in BPF program
instead of bpf_l3_csum_replace, which is totally inlined and efficient.
However, we can't do this for bpf_l4_csum_replace for now, as we can't
update skb->csum, which can cause skb->csum invalid in the rx path with
CHECKSUM_COMPLETE mode.
What's more, we can't use the direct data access and have to use
skb_store_bytes() with the BPF_F_RECOMPUTE_CSUM flag in some case, such
as modifing the vni in the vxlan header and the underlay udp header has
no checksum.
In the first patch, we make skb->csum readable and writable, and we make
skb->ip_summed readable. For now, for tc only. With these 2 fields, we
don't need to call bpf helpers for csum update any more.
In the second patch, we add some testcases for the read/write testing for
skb->csum and skb->ip_summed.
If this series is acceptable, we can define the inlined functions for csum
update in libbpf in the next step.
Menglong Dong (2):
bpf: add csum/ip_summed fields to __sk_buff
testcases/bpf: add testcases for skb->csum to ctx_skb.c
include/linux/skbuff.h | 2 +
include/uapi/linux/bpf.h | 2 +
net/core/filter.c | 22 ++++++++++
tools/include/uapi/linux/bpf.h | 2 +
.../testing/selftests/bpf/verifier/ctx_skb.c | 43 +++++++++++++++++++
5 files changed, 71 insertions(+)
--
2.39.2
next reply other threads:[~2023-12-29 8:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-29 8:14 Menglong Dong [this message]
2023-12-29 8:14 ` [PATCH bpf-next 1/2] bpf: add csum/ip_summed fields to __sk_buff Menglong Dong
2023-12-29 8:14 ` [PATCH bpf-next 2/2] testcases/bpf: add testcases for skb->csum to ctx_skb.c Menglong Dong
2024-01-02 18:11 ` [PATCH bpf-next 0/2] bpf: add csum/ip_summed fields to __sk_buff Stanislav Fomichev
2024-01-03 0:52 ` Martin KaFai Lau
2024-01-03 2:54 ` Menglong Dong
2024-01-03 3:55 ` Yonghong Song
2024-01-03 6:03 ` Menglong Dong
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