From: Lorenzo Bianconi lorenzo@kernel.org
[ Upstream commit 200a89e3e88786b52bc1dd5f26a310c097f4c6a7 ]
Forward the packet to the kernel if the gw router mac address is missing in to trigger ARP discovery.
Fixes: 85bf1f51691c ("samples: bpf: Convert xdp_router_ipv4 to XDP samples helper") Signed-off-by: Lorenzo Bianconi lorenzo@kernel.org Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/60bde5496d108089080504f58199bcf1143ea938.1653471... Signed-off-by: Sasha Levin sashal@kernel.org --- samples/bpf/xdp_router_ipv4.bpf.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/samples/bpf/xdp_router_ipv4.bpf.c b/samples/bpf/xdp_router_ipv4.bpf.c index 248119ca7938..0643330d1d2e 100644 --- a/samples/bpf/xdp_router_ipv4.bpf.c +++ b/samples/bpf/xdp_router_ipv4.bpf.c @@ -150,6 +150,15 @@ int xdp_router_ipv4_prog(struct xdp_md *ctx)
dest_mac = bpf_map_lookup_elem(&arp_table, &prefix_value->gw); + if (!dest_mac) { + /* Forward the packet to the kernel in + * order to trigger ARP discovery for + * the default gw. + */ + if (rec) + NO_TEAR_INC(rec->xdp_pass); + return XDP_PASS; + } } }