if (memcmp(shname, "kprobe/", 7) == 0 || memcmp(shname, "kretprobe/", 10) == 0 || memcmp(shname, "tracepoint/", 11) == 0 || memcmp(shname, "xdp", 3) == 0 || memcmp(shname, "perf_event", 10) == 0 || memcmp(shname, "socket", 6) == 0 || memcmp(shname, ...
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), /* 函数的返回值为value所在内存的地址,放在R0寄存器中*/ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), /* 如果返回的内存地址为0,则向下跳两个指令 */ BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */ BPF_RAW...
其中,BPF_CALL为真正的BPF调用指令,dst_reg为目的寄存器,sec_reg为源寄存器,off为偏移量,imm为立即数。 进行替换后得到如图示结构体,code表示操作码,在内核中分别定义为 #defineBPF_JMP 0x05 #defineBPF_CALL 0x80 按位与后得到code的值为85,目的寄存器、源寄存器和off均被初始化为0,imm为枚举结构中的整型值...
BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) { regs_set_return_value(regs, rc); override_function_with_return(regs); return 0; } static const struct bpf_func_proto bpf_override_return_proto = { .func = bpf_override_return, .gpl...
这里会报错的,可以自己调大一点看看charcomm_name[30];bpf_get_current_comm(comm_name,sizeof(comm_name));// 调用失败以后会直接 fall throughbpf_tail_call(ctx, &progs, this_syscall);charfmt[] ="syscall=%d common=%s\n";bpf_trace_printk(fmt,sizeof(fmt), this_syscall, comm_name);return0...
bf a1 00 00 00 00 00 00 r1 = r10 8: 07 01 00 00 f0 ff ff ff r1 += -0x10 ; bpf_printk("Hello world!\n"); 9: b7 02 00 00 0e 00 00 00 r2 = 0xe 10: 85 00 00 00 06 00 00 00 call 0x6 ; return 0; 11: b7 00 00 00 00 00 00 00 r0 = 0x0 12: 95 00 ...
内核态:bpf_tail_call辅助函数,其负责跳转到另一个 eBPF 程序,其函数定义是这样的static long (*bpf_tail_call)(void *ctx, void *prog_array_map, __u32 index),ctx是上下文,prog_array_map是前面说的BPF_MAP_TYPE_PROG_ARRAY类型的map,用于用户态...
BPF虽然不能函数调用,但是它可以使用Tail Call机制从一个BPF程序直接跳转到另一个BPF程序。它需要通过BPF_MAP_TYPE_PROG_ARRAY类型的map来知道另一个BPF程序的指针。这种跳转的次数也是有限制的,32次; BPF程序可以调用一些内核函数来辅助做一些事情(helper function); ...
yhs@ubuntu:~/work/fuzzer/net-next$ git diff diff --git a/Makefile b/Makefile index c361593..cacbe0f 100644 --- a/Makefile +++ b/Makefile @@ -686,6 +686,8 @@ KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare) # See modpost pattern 2 KBUILD_CFLAGS += $(call...
@@ -4655,6 +4745,11 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn mark_reg_known_zero(env, regs, BPF_REG_0); regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL; regs[BPF_REG_0].id = ++env->id_gen; } else if (fn->ret_type == ...