lib/bpf/bpf_dump.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright (c) 2021 Stephen Hemminger
   3  * Based on filter2xdp
   4  * Copyright (C) 2017 Tobias Klauser
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdint.h>
   9
  10 #include "rte_bpf.h"
  11
  12 #define BPF_OP_INDEX(x) (BPF_OP(x) >> 4)
  13 #define BPF_SIZE_INDEX(x) (BPF_SIZE(x) >> 3)
  14
  15 static const char *const class_tbl[] = {
  16         [BPF_LD] = "ld",   [BPF_LDX] = "ldx",    [BPF_ST] = "st",
  17         [BPF_STX] = "stx", [BPF_ALU] = "alu",    [BPF_JMP] = "jmp",
  18         [BPF_RET] = "ret", [BPF_MISC] = "alu64",
  19 };
  20
  21 static const char *const alu_op_tbl[16] = {
  22         [BPF_ADD >> 4] = "add",    [BPF_SUB >> 4] = "sub",
  23         [BPF_MUL >> 4] = "mul",    [BPF_DIV >> 4] = "div",
  24         [BPF_OR >> 4] = "or",      [BPF_AND >> 4] = "and",
  25         [BPF_LSH >> 4] = "lsh",    [BPF_RSH >> 4] = "rsh",
  26         [BPF_NEG >> 4] = "neg",    [BPF_MOD >> 4] = "mod",
  27         [BPF_XOR >> 4] = "xor",    [EBPF_MOV >> 4] = "mov",
  28         [EBPF_ARSH >> 4] = "arsh", [EBPF_END >> 4] = "endian",
  29 };
  30
  31 static const char *const size_tbl[] = {
  32         [BPF_W >> 3] = "w",
  33         [BPF_H >> 3] = "h",
  34         [BPF_B >> 3] = "b",
  35         [EBPF_DW >> 3] = "dw",
  36 };
  37
  38 static const char *const jump_tbl[16] = {
  39         [BPF_JA >> 4] = "ja",      [BPF_JEQ >> 4] = "jeq",
  40         [BPF_JGT >> 4] = "jgt",    [BPF_JGE >> 4] = "jge",
  41         [BPF_JSET >> 4] = "jset",  [EBPF_JNE >> 4] = "jne",
  42         [EBPF_JSGT >> 4] = "jsgt", [EBPF_JSGE >> 4] = "jsge",
  43         [EBPF_CALL >> 4] = "call", [EBPF_EXIT >> 4] = "exit",
  44 };
  45
  46 void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len)
  47 {
  48         uint32_t i;
  49
  50         for (i = 0; i < len; ++i) {
  51                 const struct ebpf_insn *ins = buf + i;
  52                 uint8_t cls = BPF_CLASS(ins->code);
  53                 const char *op, *postfix = "";
  54
  55                 fprintf(f, " L%u:\t", i);
  56
  57                 switch (cls) {
  58                 default:
  59                         fprintf(f, "unimp 0x%x // class: %s\n",
  60                                 ins->code, class_tbl[cls]);
  61                         break;
  62                 case BPF_ALU:
  63                         postfix = "32";
  64                         /* fall through */
  65                 case EBPF_ALU64:
  66                         op = alu_op_tbl[BPF_OP_INDEX(ins->code)];
  67                         if (BPF_SRC(ins->code) == BPF_X)
  68                                 fprintf(f, "%s%s r%u, r%u\n", op, postfix, ins->dst_reg,
  69                                         ins->src_reg);
  70                         else
  71                                 fprintf(f, "%s%s r%u, #0x%x\n", op, postfix,
  72                                         ins->dst_reg, ins->imm);
  73                         break;
  74                 case BPF_LD:
  75                         op = "ld";
  76                         postfix = size_tbl[BPF_SIZE_INDEX(ins->code)];
  77                         if (ins->code == (BPF_LD | BPF_IMM | EBPF_DW)) {
  78                                 uint64_t val;
  79
  80                                 val = (uint32_t)ins[0].imm |
  81                                         (uint64_t)(uint32_t)ins[1].imm << 32;
  82                                 fprintf(f, "%s%s r%d, #0x%"PRIx64"\n",
  83                                         op, postfix, ins->dst_reg, val);
  84                                 i++;
  85                         } else if (BPF_MODE(ins->code) == BPF_IMM)
  86                                 fprintf(f, "%s%s r%d, #0x%x\n", op, postfix,
  87                                         ins->dst_reg, ins->imm);
  88                         else if (BPF_MODE(ins->code) == BPF_ABS)
  89                                 fprintf(f, "%s%s r%d, [%d]\n", op, postfix,
  90                                         ins->dst_reg, ins->imm);
  91                         else if (BPF_MODE(ins->code) == BPF_IND)
  92                                 fprintf(f, "%s%s r%d, [r%u + %d]\n", op, postfix,
  93                                         ins->dst_reg, ins->src_reg, ins->imm);
  94                         else
  95                                 fprintf(f, "// BUG: LD opcode 0x%02x in eBPF insns\n",
  96                                         ins->code);
  97                         break;
  98                 case BPF_LDX:
  99                         op = "ldx";
 100                         postfix = size_tbl[BPF_SIZE_INDEX(ins->code)];
 101                         fprintf(f, "%s%s r%d, [r%u + %d]\n", op, postfix, ins->dst_reg,
 102                                 ins->src_reg, ins->off);
 103                         break;
 104                 case BPF_ST:
 105                         op = "st";
 106                         postfix = size_tbl[BPF_SIZE_INDEX(ins->code)];
 107                         if (BPF_MODE(ins->code) == BPF_MEM)
 108                                 fprintf(f, "%s%s [r%d + %d], #0x%x\n", op, postfix,
 109                                         ins->dst_reg, ins->off, ins->imm);
 110                         else
 111                                 fprintf(f, "// BUG: ST opcode 0x%02x in eBPF insns\n",
 112                                         ins->code);
 113                         break;
 114                 case BPF_STX:
 115                         op = "stx";
 116                         postfix = size_tbl[BPF_SIZE_INDEX(ins->code)];
 117                         fprintf(f, "%s%s [r%d + %d], r%u\n", op, postfix,
 118                                 ins->dst_reg, ins->off, ins->src_reg);
 119                         break;
 120 #define L(pc, off) ((int)(pc) + 1 + (off))
 121                 case BPF_JMP:
 122                         op = jump_tbl[BPF_OP_INDEX(ins->code)];
 123                         if (op == NULL)
 124                                 fprintf(f, "invalid jump opcode: %#x\n", ins->code);
 125                         else if (BPF_OP(ins->code) == BPF_JA)
 126                                 fprintf(f, "%s L%d\n", op, L(i, ins->off));
 127                         else if (BPF_OP(ins->code) == EBPF_EXIT)
 128                                 fprintf(f, "%s\n", op);
 129                         else
 130                                 fprintf(f, "%s r%u, #0x%x, L%d\n", op, ins->dst_reg,
 131                                         ins->imm, L(i, ins->off));
 132                         break;
 133                 case BPF_RET:
 134                         fprintf(f, "// BUG: RET opcode 0x%02x in eBPF insns\n",
 135                                 ins->code);
 136                         break;
 137                 }
 138         }
 139 }