From: Gerhard Engleder gerhard@engleder-embedded.com
[ Upstream commit 7a698edf954cb3f8b6e8dacdb77615355170420c ]
xdp2_kern rewrites and forwards packets out on the same interface. Forwarding still works but rewrite got broken when xdp multibuffer support has been added.
With xdp multibuffer a local copy of the packet has been introduced. The MAC address is now swapped in the local copy, but the local copy in not written back.
Fix MAC address swapping be adding write back of modified packet.
Fixes: 772251742262 ("samples/bpf: fixup some tools to be able to support xdp multibuffer") Signed-off-by: Gerhard Engleder gerhard@engleder-embedded.com Reviewed-by: Andy Gospodarek gospo@broadcom.com Link: https://lore.kernel.org/r/20221015213050.65222-1-gerhard@engleder-embedded.c... Signed-off-by: Martin KaFai Lau martin.lau@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- samples/bpf/xdp2_kern.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/samples/bpf/xdp2_kern.c b/samples/bpf/xdp2_kern.c index 3332ba6bb95f..67804ecf7ce3 100644 --- a/samples/bpf/xdp2_kern.c +++ b/samples/bpf/xdp2_kern.c @@ -112,6 +112,10 @@ int xdp_prog1(struct xdp_md *ctx)
if (ipproto == IPPROTO_UDP) { swap_src_dst_mac(data); + + if (bpf_xdp_store_bytes(ctx, 0, pkt, sizeof(pkt))) + return rc; + rc = XDP_TX; }