From 9739eef13c926645fbf88bcb77e66442fa75d688 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 8 May 2014 14:10:51 -0700 Subject: 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 Signed-off-by: David S. Miller --- include/linux/filter.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) (limited to 'include') 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) -- cgit v1.2.3