UPSTREAM: netfilter: xt_bpf: support ebpf

Add support for attaching an eBPF object by file descriptor.

The iptables binary can be called with a path to an elf object or a
pinned bpf object. Also pass the mode and path to the kernel to be
able to return it later for iptables dump and save.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Chenbo Feng <fengc@google.com>
(cherry picked from commit 2c16d60332643e90d4fa244f4a706c454b8c7569)

Change-Id: I31b8831a7ffd7c44985ee906ff194c1d934dafbe
diff --git a/include/uapi/linux/netfilter/xt_bpf.h b/include/uapi/linux/netfilter/xt_bpf.h
index 1fad2c2..b97725a 100644
--- a/include/uapi/linux/netfilter/xt_bpf.h
+++ b/include/uapi/linux/netfilter/xt_bpf.h
@@ -2,9 +2,11 @@
 #define _XT_BPF_H
 
 #include <linux/filter.h>
+#include <linux/limits.h>
 #include <linux/types.h>
 
 #define XT_BPF_MAX_NUM_INSTR	64
+#define XT_BPF_PATH_MAX		(XT_BPF_MAX_NUM_INSTR * sizeof(struct sock_filter))
 
 struct bpf_prog;
 
@@ -16,4 +18,23 @@
 	struct bpf_prog *filter __attribute__((aligned(8)));
 };
 
+enum xt_bpf_modes {
+	XT_BPF_MODE_BYTECODE,
+	XT_BPF_MODE_FD_PINNED,
+	XT_BPF_MODE_FD_ELF,
+};
+
+struct xt_bpf_info_v1 {
+	__u16 mode;
+	__u16 bpf_program_num_elem;
+	__s32 fd;
+	union {
+		struct sock_filter bpf_program[XT_BPF_MAX_NUM_INSTR];
+		char path[XT_BPF_PATH_MAX];
+	};
+
+	/* only used in the kernel */
+	struct bpf_prog *filter __attribute__((aligned(8)));
+};
+
 #endif /*_XT_BPF_H */