selftest/bpf: Fix IPV6FR handling in flow dissector

From second fragment on, IPV6FR program must stop the dissection of IPV6
fragmented packet. This is the same approach used for IPV4 fragmentation.
This fixes the flow keys calculation for the upper-layer protocols.
Note that according to RFC8200, the first fragment packet must include
the upper-layer header.

Signed-off-by: Santucci Pierpaolo <santucci@epigenesys.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/X7JUzUj34ceE2wBm@santucci.pierpaolo

diff --git a/tools/testing/selftests/bpf/progs/bpf_flow.c b/tools/testing/selftests/bpf/progs/bpf_flow.c
index 5a65f6b51377d2fc12f07d7c87a33b89868a0429..95a5a0778ed719cd0e365c8baaa3670ece674304 100644 (file)
--- a/tools/testing/selftests/bpf/progs/bpf_flow.c
+++ b/tools/testing/selftests/bpf/progs/bpf_flow.c
@@ -368,6 +368,8 @@ PROG(IPV6FR)(struct __sk_buff *skb)
                 */
                if (!(keys->flags & BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
                        return export_flow_keys(keys, BPF_OK);
+       } else {
+               return export_flow_keys(keys, BPF_OK);
        }
 
        return parse_ipv6_proto(skb, fragh->nexthdr);