net: filter: improve filter block macros

Commit 9739eef1 ("net: filter: make BPF conversion more readable")
started to introduce helper macros similar to BPF_STMT()/BPF_JUMP()
macros from classic BPF.

However, quite some statements in the filter conversion functions
remained in the old style which gives a mixture of block macros and
non block macros in the code. This patch makes the block macros itself
more readable by using explicit member initialization, and converts
the remaining ones where possible to remain in a more consistent state.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/filter.h

@@ -76,56 +76,211 @@ enum {
 /* BPF program can access up to 512 bytes of stack space. */
 #define MAX_BPF_STACK	512
 
-/* bpf_add|sub|...: a += x, bpf_mov: a = x */
-#define BPF_ALU64_REG(op, a, x) \
-	((struct sock_filter_int) {BPF_ALU64|BPF_OP(op)|BPF_X, a, x, 0, 0})
-#define BPF_ALU32_REG(op, a, x) \
-	((struct sock_filter_int) {BPF_ALU|BPF_OP(op)|BPF_X, a, x, 0, 0})
-
-/* bpf_add|sub|...: a += imm, bpf_mov: a = imm */
-#define BPF_ALU64_IMM(op, a, imm) \
-	((struct sock_filter_int) {BPF_ALU64|BPF_OP(op)|BPF_K, a, 0, 0, imm})
-#define BPF_ALU32_IMM(op, a, imm) \
-	((struct sock_filter_int) {BPF_ALU|BPF_OP(op)|BPF_K, a, 0, 0, imm})
-
-/* R0 = *(uint *) (skb->data + off) */
-#define BPF_LD_ABS(size, off) \
-	((struct sock_filter_int) {BPF_LD|BPF_SIZE(size)|BPF_ABS, 0, 0, 0, off})
-
-/* R0 = *(uint *) (skb->data + x + off) */
-#define BPF_LD_IND(size, x, off) \
-	((struct sock_filter_int) {BPF_LD|BPF_SIZE(size)|BPF_IND, 0, x, 0, off})
-
-/* a = *(uint *) (x + off) */
-#define BPF_LDX_MEM(sz, a, x, off) \
-	((struct sock_filter_int) {BPF_LDX|BPF_SIZE(sz)|BPF_MEM, a, x, off, 0})
-
-/* if (a 'op' x) goto pc+off */
-#define BPF_JMP_REG(op, a, x, off) \
-	((struct sock_filter_int) {BPF_JMP|BPF_OP(op)|BPF_X, a, x, off, 0})
-
-/* if (a 'op' imm) goto pc+off */
-#define BPF_JMP_IMM(op, a, imm, off) \
-	((struct sock_filter_int) {BPF_JMP|BPF_OP(op)|BPF_K, a, 0, off, imm})
-
-#define BPF_EXIT_INSN() \
-	((struct sock_filter_int) {BPF_JMP|BPF_EXIT, 0, 0, 0, 0})
-
-static inline int size_to_bpf(int size)
-{
-	switch (size) {
-	case 1:
-		return BPF_B;
-	case 2:
-		return BPF_H;
-	case 4:
-		return BPF_W;
-	case 8:
-		return BPF_DW;
-	default:
-		return -EINVAL;
-	}
-}
+/* Helper macros for filter block array initializers. */
+
+/* ALU ops on registers, bpf_add|sub|...: A += X */
+
+#define BPF_ALU64_REG(OP, A, X)					\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,	\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = 0,					\
+		.imm   = 0 })
+
+#define BPF_ALU32_REG(OP, A, X)					\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU | BPF_OP(OP) | BPF_X,		\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = 0,					\
+		.imm   = 0 })
+
+/* ALU ops on immediates, bpf_add|sub|...: A += IMM */
+
+#define BPF_ALU64_IMM(OP, A, IMM)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,	\
+		.a_reg = A,					\
+		.x_reg = 0,					\
+		.off   = 0,					\
+		.imm   = IMM })
+
+#define BPF_ALU32_IMM(OP, A, IMM)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU | BPF_OP(OP) | BPF_K,		\
+		.a_reg = A,					\
+		.x_reg = 0,					\
+		.off   = 0,					\
+		.imm   = IMM })
+
+/* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
+
+#define BPF_ENDIAN(TYPE, A, LEN)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),	\
+		.a_reg = A,					\
+		.x_reg = 0,					\
+		.off   = 0,					\
+		.imm   = LEN })
+
+/* Short form of mov, A = X */
+
+#define BPF_MOV64_REG(A, X)					\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU64 | BPF_MOV | BPF_X,		\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = 0,					\
+		.imm   = 0 })
+
+#define BPF_MOV32_REG(A, X)					\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU | BPF_MOV | BPF_X,		\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = 0,					\
+		.imm   = 0 })
+
+/* Short form of mov, A = IMM */
+
+#define BPF_MOV64_IMM(A, IMM)					\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU64 | BPF_MOV | BPF_K,		\
+		.a_reg = A,					\
+		.x_reg = 0,					\
+		.off   = 0,					\
+		.imm   = IMM })
+
+#define BPF_MOV32_IMM(A, IMM)					\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU | BPF_MOV | BPF_K,		\
+		.a_reg = A,					\
+		.x_reg = 0,					\
+		.off   = 0,					\
+		.imm   = IMM })
+
+/* Short form of mov based on type, BPF_X: A = X,  BPF_K: A = IMM */
+
+#define BPF_MOV64_RAW(TYPE, A, X, IMM)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),	\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = 0,					\
+		.imm   = IMM })
+
+#define BPF_MOV32_RAW(TYPE, A, X, IMM)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),	\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = 0,					\
+		.imm   = IMM })
+
+/* Direct packet access, R0 = *(uint *) (skb->data + OFF) */
+
+#define BPF_LD_ABS(SIZE, OFF)					\
+	((struct sock_filter_int) {				\
+		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,	\
+		.a_reg = 0,					\
+		.x_reg = 0,					\
+		.off   = 0,					\
+		.imm   = OFF })
+
+/* Indirect packet access, R0 = *(uint *) (skb->data + X + OFF) */
+
+#define BPF_LD_IND(SIZE, X, OFF)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,	\
+		.a_reg = 0,					\
+		.x_reg = X,					\
+		.off   = 0,					\
+		.imm   = OFF })
+
+/* Memory store, A = *(uint *) (X + OFF), and vice versa */
+
+#define BPF_LDX_MEM(SIZE, A, X, OFF)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,	\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = OFF,					\
+		.imm   = 0 })
+
+#define BPF_STX_MEM(SIZE, A, X, OFF)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,	\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = OFF,					\
+		.imm   = 0 })
+
+/* Conditional jumps against registers, if (A 'op' X) goto pc + OFF */
+
+#define BPF_JMP_REG(OP, A, X, OFF)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_JMP | BPF_OP(OP) | BPF_X,		\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = OFF,					\
+		.imm   = 0 })
+
+/* Conditional jumps against immediates, if (A 'op' IMM) goto pc + OFF */
+
+#define BPF_JMP_IMM(OP, A, IMM, OFF)				\
+	((struct sock_filter_int) {				\
+		.code  = BPF_JMP | BPF_OP(OP) | BPF_K,		\
+		.a_reg = A,					\
+		.x_reg = 0,					\
+		.off   = OFF,					\
+		.imm   = IMM })
+
+/* Function call */
+
+#define BPF_EMIT_CALL(FUNC)					\
+	((struct sock_filter_int) {				\
+		.code  = BPF_JMP | BPF_CALL,			\
+		.a_reg = 0,					\
+		.x_reg = 0,					\
+		.off   = 0,					\
+		.imm   = ((FUNC) - __bpf_call_base) })
+
+/* Raw code statement block */
+
+#define BPF_RAW_INSN(CODE, A, X, OFF, IMM)			\
+	((struct sock_filter_int) {				\
+		.code  = CODE,					\
+		.a_reg = A,					\
+		.x_reg = X,					\
+		.off   = OFF,					\
+		.imm   = IMM })
+
+/* Program exit */
+
+#define BPF_EXIT_INSN()						\
+	((struct sock_filter_int) {				\
+		.code  = BPF_JMP | BPF_EXIT,			\
+		.a_reg = 0,					\
+		.x_reg = 0,					\
+		.off   = 0,					\
+		.imm   = 0 })
+
+#define bytes_to_bpf_size(bytes)				\
+({								\
+	int bpf_size = -EINVAL;					\
+								\
+	if (bytes == sizeof(u8))				\
+		bpf_size = BPF_B;				\
+	else if (bytes == sizeof(u16))				\
+		bpf_size = BPF_H;				\
+	else if (bytes == sizeof(u32))				\
+		bpf_size = BPF_W;				\
+	else if (bytes == sizeof(u64))				\
+		bpf_size = BPF_DW;				\
+								\
+	bpf_size;						\
+})
 
 /* Macro to invoke filter function. */
 #define SK_RUN_FILTER(filter, ctx)  (*filter->bpf_func)(ctx, filter->insnsi)