Exemplo n.º 1
0
static int prog_load(int map_fd, int verdict)
{
	struct bpf_insn prog[] = {
		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), /* save r6 so it's not clobbered by BPF_CALL */

		/* Count packets */
		BPF_MOV64_IMM(BPF_REG_0, MAP_KEY_PACKETS), /* r0 = 0 */
		BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
		BPF_LD_MAP_FD(BPF_REG_1, map_fd), /* load map fd to r1 */
		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
		BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
		BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */
		BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */

		/* Count bytes */
		BPF_MOV64_IMM(BPF_REG_0, MAP_KEY_BYTES), /* r0 = 1 */
		BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
		BPF_LD_MAP_FD(BPF_REG_1, map_fd),
		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
		BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
		BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6, offsetof(struct __sk_buff, len)), /* r1 = skb->len */
		BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */

		BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */
		BPF_EXIT_INSN(),
	};

	return bpf_prog_load(BPF_PROG_TYPE_CGROUP_SKB,
			     prog, sizeof(prog), "GPL", 0);
}
Exemplo n.º 2
0
static int prog_load_cnt(int verdict, int val)
{
	int cgroup_storage_fd, percpu_cgroup_storage_fd;

	if (map_fd < 0)
		map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, 4, 8, 1, 0);
	if (map_fd < 0) {
		printf("failed to create map '%s'\n", strerror(errno));
		return -1;
	}

	cgroup_storage_fd = bpf_create_map(BPF_MAP_TYPE_CGROUP_STORAGE,
				sizeof(struct bpf_cgroup_storage_key), 8, 0, 0);
	if (cgroup_storage_fd < 0) {
		printf("failed to create map '%s'\n", strerror(errno));
		return -1;
	}

	percpu_cgroup_storage_fd = bpf_create_map(
		BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
		sizeof(struct bpf_cgroup_storage_key), 8, 0, 0);
	if (percpu_cgroup_storage_fd < 0) {
		printf("failed to create map '%s'\n", strerror(errno));
		return -1;
	}

	struct bpf_insn prog[] = {
		BPF_MOV32_IMM(BPF_REG_0, 0),
		BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
		BPF_LD_MAP_FD(BPF_REG_1, map_fd),
		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
		BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
		BPF_MOV64_IMM(BPF_REG_1, val), /* r1 = 1 */
		BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */

		BPF_LD_MAP_FD(BPF_REG_1, cgroup_storage_fd),
		BPF_MOV64_IMM(BPF_REG_2, 0),
		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_local_storage),
		BPF_MOV64_IMM(BPF_REG_1, val),
		BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_W, BPF_REG_0, BPF_REG_1, 0, 0),

		BPF_LD_MAP_FD(BPF_REG_1, percpu_cgroup_storage_fd),
		BPF_MOV64_IMM(BPF_REG_2, 0),
		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_local_storage),
		BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_0, 0),
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 0x1),
		BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_3, 0),

		BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */
		BPF_EXIT_INSN(),
	};
	size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);
	int ret;

	ret = bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB,
			       prog, insns_cnt, "GPL", 0,
			       bpf_log_buf, BPF_LOG_BUF_SIZE);

	if (ret < 0) {
		log_err("Loading program");
		printf("Output from verifier:\n%s\n-------\n", bpf_log_buf);
		return 0;
	}
	close(cgroup_storage_fd);
	return ret;
}