Commit 26101f5ab6bd ("bpf: Add source ip in "struct bpf_tunnel_key"")
added support for getting and setting the outer source IP of encapsulated
packets via the bpf_skb_{get,set}_tunnel_key BPF helper. This change
allows BPF programs to set any IP address as the source, including for
example the IP address of a container running on the same host.
In that last case, however, the encapsulated packets are dropped when
looking up the route because the source IP address isn't assigned to any
interface on the host. To avoid this, we need to set the
FLOWI_FLAG_ANYSRC flag.
Fixes: 26101f5ab6bd ("bpf: Add source ip in "struct bpf_tunnel_key"")
Acked-by: Martin KaFai Lau <kafai@xxxxxx>
Reviewed-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>
Signed-off-by: Paul Chaignon <paul@xxxxxxxxxxxxx>
---
net/core/filter.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/core/filter.c b/net/core/filter.c
index 57c5e4c4efd2..dffc7dcda96a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4653,6 +4653,7 @@ BPF_CALL_4(bpf_skb_set_tunnel_key, struct sk_buff *, skb,
} else {
info->key.u.ipv4.dst = cpu_to_be32(from->remote_ipv4);
info->key.u.ipv4.src = cpu_to_be32(from->local_ipv4);
+ info->key.flow_flags = FLOWI_FLAG_ANYSRC;
}
return 0;
--
2.25.1
