[PATCH 6.4 139/800] samples/bpf: xdp1 and xdp2 reduce XDPBUFSIZE to 60

Greg Kroah-Hartman
2023-07-16T19:59:20Z

From: Jesper Dangaard Brouer <brouer@redhat.com>

[ Upstream commit 60548b825b082cedf89b275c21c28b1e1d030e50 ]

Default samples/pktgen scripts send 60 byte packets as hardware adds
4-bytes FCS checksum, which fulfils minimum Ethernet 64 bytes frame
size.

XDP layer will not necessary have access to the 4-bytes FCS checksum.

This leads to bpf_xdp_load_bytes() failing as it tries to copy 64-bytes
from an XDP packet that only have 60-bytes available.

Fixes: 772251742262 ("samples/bpf: fixup some tools to be able to support xdp multibuffer")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/bpf/168545704139.2996228.2516528552939485216.stgit@firesoul
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
samples/bpf/xdp1_kern.c | 2 +-
samples/bpf/xdp2_kern.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/samples/bpf/xdp1_kern.c b/samples/bpf/xdp1_kern.c
index 0a5c704badd00..d91f27cbcfa99 100644
--- a/samples/bpf/xdp1_kern.c
+++ b/samples/bpf/xdp1_kern.c
@@ -39,7 +39,7 @@ static int parse_ipv6(void *data, u64 nh_off, void *data_end)
return ip6h->nexthdr;
}

-#define XDPBUFSIZE 64
+#define XDPBUFSIZE 60
SEC("xdp.frags")
int xdp_prog1(struct xdp_md *ctx)
{
diff --git a/samples/bpf/xdp2_kern.c b/samples/bpf/xdp2_kern.c
index 67804ecf7ce37..8bca674451ed1 100644
--- a/samples/bpf/xdp2_kern.c
+++ b/samples/bpf/xdp2_kern.c
@@ -55,7 +55,7 @@ static int parse_ipv6(void *data, u64 nh_off, void *data_end)
return ip6h->nexthdr;
}

-#define XDPBUFSIZE 64
+#define XDPBUFSIZE 60
SEC("xdp.frags")
int xdp_prog1(struct xdp_md *ctx)
{
--
2.39.2