bpf: Change bpf_fib_lookup to return -EAFNOSUPPORT for unsupported address families

Update bpf_fib_lookup to return -EAFNOSUPPORT for unsupported address
families. Allows userspace to probe for support as more are added
(e.g., AF_MPLS).

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index 81bd2e9fe8fc..885fb0e2f264 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4285,7 +4285,7 @@ BPF_CALL_4(bpf_xdp_fib_lookup, struct xdp_buff *, ctx,
                                            flags, true);
 #endif
         }
-        return 0;
+        return -EAFNOSUPPORT;
 }
 
 static const struct bpf_func_proto bpf_xdp_fib_lookup_proto = {
@@ -4302,7 +4302,7 @@ BPF_CALL_4(bpf_skb_fib_lookup, struct sk_buff *, skb,
            struct bpf_fib_lookup *, params, int, plen, u32, flags)
 {
         struct net *net = dev_net(skb->dev);
-        int index = 0;
+        int index = -EAFNOSUPPORT;
 
         if (plen < sizeof(*params))
                 return -EINVAL;