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authorAlexei Starovoitov <ast@plumgrid.com>2014-05-08 14:10:51 -0700
committerDavid S. Miller <davem@davemloft.net>2014-05-12 00:23:55 -0400
commit9739eef13c926645fbf88bcb77e66442fa75d688 (patch)
treed6934c95e5eae0027f755caf5ea7c1ab2aede94e /include
parent05ab2dae650e09add1c5295392b5516704c03a4b (diff)
net: filter: make BPF conversion more readable
Introduce BPF helper macros to define instructions (similar to old BPF_STMT/BPF_JUMP macros) Use them while converting classic BPF to internal and in BPF testsuite later. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/linux/filter.h51
1 files changed, 51 insertions, 0 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index ed1efab10b8f..4457b383961c 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -79,6 +79,57 @@ 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;
+ }
+}
+
/* Macro to invoke filter function. */
#define SK_RUN_FILTER(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)