sample: bpf: xdp_router_ipv4: Allow the kernel to send arp requests

Forward the packet to the kernel if the gw router mac address is missing
in to trigger ARP discovery.

Fixes: 85bf1f5169 ("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/60bde5496d108089080504f58199bcf1143ea938.1653471558.git.lorenzo@kernel.org
This commit is contained in:
Lorenzo Bianconi 2022-05-25 11:44:27 +02:00 committed by Andrii Nakryiko
parent 610cd93b44
commit 200a89e3e8

View File

@ -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;
}
}
}