ebpf: maintain a copy of kernel UAPI header file linux/bpf.h

ebpf/Makefile.am

@@ -1,9 +1,12 @@
 if BUILD_EBPF
 
+# Maintaining a local copy of UAPI linux/bpf.h
+BPF_CFLAGS = -Iinclude
+
 all: lb.bpf filter.bpf bypass_filter.bpf xdp_filter.bpf vlan_filter.bpf
 
 %.bpf: %.c
-	${CC} -Wall -O2 -D__KERNEL__ -D__ASM_SYSREG_H -emit-llvm -c $< -o - | ${LLC} -march=bpf -filetype=obj -o $@
+	${CC} -Wall $(BPF_CFLAGS) -O2 -D__KERNEL__ -D__ASM_SYSREG_H -emit-llvm -c $< -o - | ${LLC} -march=bpf -filetype=obj -o $@
 
 CLEANFILES = *.bpf
 

ebpf/include/linux/bpf_common.h

@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef __LINUX_BPF_COMMON_H__
+#define __LINUX_BPF_COMMON_H__
+
+/* Instruction classes */
+#define BPF_CLASS(code) ((code) & 0x07)
+#define		BPF_LD		0x00
+#define		BPF_LDX		0x01
+#define		BPF_ST		0x02
+#define		BPF_STX		0x03
+#define		BPF_ALU		0x04
+#define		BPF_JMP		0x05
+#define		BPF_RET		0x06
+#define		BPF_MISC        0x07
+
+/* ld/ldx fields */
+#define BPF_SIZE(code)  ((code) & 0x18)
+#define		BPF_W		0x00 /* u32 */
+#define		BPF_H		0x08 /* u16 */
+#define		BPF_B		0x10 /*  u8 */
+/* eBPF		BPF_DW		0x18    u64 */
+#define BPF_MODE(code)  ((code) & 0xe0)
+#define		BPF_IMM		0x00
+#define		BPF_ABS		0x20
+#define		BPF_IND		0x40
+#define		BPF_MEM		0x60
+#define		BPF_LEN		0x80
+#define		BPF_MSH		0xa0
+
+/* alu/jmp fields */
+#define BPF_OP(code)    ((code) & 0xf0)
+#define		BPF_ADD		0x00
+#define		BPF_SUB		0x10
+#define		BPF_MUL		0x20
+#define		BPF_DIV		0x30
+#define		BPF_OR		0x40
+#define		BPF_AND		0x50
+#define		BPF_LSH		0x60
+#define		BPF_RSH		0x70
+#define		BPF_NEG		0x80
+#define		BPF_MOD		0x90
+#define		BPF_XOR		0xa0
+
+#define		BPF_JA		0x00
+#define		BPF_JEQ		0x10
+#define		BPF_JGT		0x20
+#define		BPF_JGE		0x30
+#define		BPF_JSET        0x40
+#define BPF_SRC(code)   ((code) & 0x08)
+#define		BPF_K		0x00
+#define		BPF_X		0x08
+
+#ifndef BPF_MAXINSNS
+#define BPF_MAXINSNS 4096
+#endif
+
+#endif /* __LINUX_BPF_COMMON_H__ */