flow_dissector: switch kernel context to struct bpf_flow_dissector
struct bpf_flow_dissector has a small subset of sk_buff fields that
flow dissector BPF program is allowed to access and an optional
pointer to real skb. Real skb is used only in bpf_skb_load_bytes
helper to read non-linear data.
The real motivation for this is to be able to call flow dissector
from eth_get_headlen context where we don't have an skb and need
to dissect raw bytes.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 2b26979..7c5a8d9 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -305,4 +305,11 @@ static inline void *skb_flow_dissector_target(struct flow_dissector *flow_dissec
return ((char *)target_container) + flow_dissector->offset[key_id];
}
+struct bpf_flow_dissector {
+ struct bpf_flow_keys *flow_keys;
+ const struct sk_buff *skb;
+ void *data;
+ void *data_end;
+};
+
#endif