// SPDX-License-Identifier: GPL-2.0 #include <test_progs.h> void test_flow_dissector_load_bytes(void) { struct bpf_flow_keys flow_keys; __u32 duration = 0, retval, size; struct bpf_insn prog[] = { // BPF_REG_1 - 1st argument: context // BPF_REG_2 - 2nd argument: offset, start at first byte BPF_MOV64_IMM(BPF_REG_2, 0), // BPF_REG_3 - 3rd argument: destination, reserve byte on stack BPF_ALU64_REG(BPF_MOV, BPF_REG_3, BPF_REG_10), BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -1), // BPF_REG_4 - 4th argument: copy one byte BPF_MOV64_IMM(BPF_REG_4, 1), // bpf_skb_load_bytes(ctx, sizeof(pkt_v4), ptr, 1) BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_skb_load_bytes), BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2), // if (ret == 0) return BPF_DROP (2) BPF_MOV64_IMM(BPF_REG_0, BPF_DROP), BPF_EXIT_INSN(), // if (ret != 0) return BPF_OK (0) BPF_MOV64_IMM(BPF_REG_0, BPF_OK), BPF_EXIT_INSN(), }; int fd, err; /* make sure bpf_skb_load_bytes is not allowed from skb-less context */ fd = bpf_load_program(BPF_PROG_TYPE_FLOW_DISSECTOR, prog, ARRAY_SIZE(prog), "GPL", 0, NULL, 0); CHECK(fd < 0, "flow_dissector-bpf_skb_load_bytes-load", "fd %d errno %d\n", fd, errno); err = bpf_prog_test_run(fd, 1, &pkt_v4, sizeof(pkt_v4), &flow_keys, &size, &retval, &duration); CHECK(size != sizeof(flow_keys) || err || retval != 1, "flow_dissector-bpf_skb_load_bytes", "err %d errno %d retval %d duration %d size %u/%zu\n", err, errno, retval, duration, size, sizeof(flow_keys)); if (fd >= -1) close(fd); }