[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <63d91da7-4040-a766-dcd7-bccbb4c02ef4@redhat.com>
Date: Tue, 30 May 2023 13:33:08 +0200
From: Jesper Dangaard Brouer <jbrouer@...hat.com>
To: Tariq Toukan <tariqt@...dia.com>, Alexei Starovoitov <ast@...nel.org>,
John Fastabend <john.fastabend@...il.com>, Jakub Kicinski <kuba@...nel.org>
Cc: brouer@...hat.com, Daniel Borkmann <daniel@...earbox.net>,
Jesper Dangaard Brouer <hawk@...nel.org>, bpf@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
netdev@...r.kernel.org, Gal Pressman <gal@...dia.com>,
Nimrod Oren <noren@...dia.com>
Subject: Re: [PATCH bpf-next 1/2] samples/bpf: fixup xdp_redirect tool to be
able to support xdp multibuffer
On 29/05/2023 13.06, Tariq Toukan wrote:
> Expand the xdp multi-buffer support to xdp_redirect tool.
> Similar to what's done in commit
> 772251742262 ("samples/bpf: fixup some tools to be able to support xdp multibuffer")
> and its fix commit
> 7a698edf954c ("samples/bpf: Fix MAC address swapping in xdp2_kern").
>
Have you tested if this cause a performance degradation?
(Also found possible bug below)
> Signed-off-by: Tariq Toukan <tariqt@...dia.com>
> Reviewed-by: Nimrod Oren <noren@...dia.com>
> ---
> samples/bpf/xdp_redirect.bpf.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/samples/bpf/xdp_redirect.bpf.c b/samples/bpf/xdp_redirect.bpf.c
> index 7c02bacfe96b..620163eb7e19 100644
> --- a/samples/bpf/xdp_redirect.bpf.c
> +++ b/samples/bpf/xdp_redirect.bpf.c
> @@ -16,16 +16,21 @@
>
> const volatile int ifindex_out;
>
> -SEC("xdp")
> +#define XDPBUFSIZE 64
Pktgen sample scripts will default send with 60 pkt length, because the
4 bytes FCS (end-frame checksum) is added by hardware.
Will this result in an error when bpf_xdp_load_bytes() tries to copy 64
bytes from a 60 bytes packet?
> +SEC("xdp.frags")
> int xdp_redirect_prog(struct xdp_md *ctx)
> {
> - void *data_end = (void *)(long)ctx->data_end;
> - void *data = (void *)(long)ctx->data;
> + __u8 pkt[XDPBUFSIZE] = {};
> + void *data_end = &pkt[XDPBUFSIZE-1];
> + void *data = pkt;
> u32 key = bpf_get_smp_processor_id();
> struct ethhdr *eth = data;
> struct datarec *rec;
> u64 nh_off;
>
> + if (bpf_xdp_load_bytes(ctx, 0, pkt, sizeof(pkt)))
> + return XDP_DROP;
E.g. sizeof(pkt) = 64 bytes here.
> +
> nh_off = sizeof(*eth);
> if (data + nh_off > data_end)
> return XDP_DROP;
> @@ -36,11 +41,14 @@ int xdp_redirect_prog(struct xdp_md *ctx)
> NO_TEAR_INC(rec->processed);
>
> swap_src_dst_mac(data);
> + if (bpf_xdp_store_bytes(ctx, 0, pkt, sizeof(pkt)))
> + return XDP_DROP;
> +
> return bpf_redirect(ifindex_out, 0);
> }
>
> /* Redirect require an XDP bpf_prog loaded on the TX device */
> -SEC("xdp")
> +SEC("xdp.frags")
> int xdp_redirect_dummy_prog(struct xdp_md *ctx)
> {
> return XDP_PASS;
Powered by blists - more mailing lists