1 // SPDX-License-Identifier: GPL-2.0 2 #include <test_progs.h> 3 4 void test_flow_dissector_load_bytes(void) 5 { 6 struct bpf_flow_keys flow_keys; 7 __u32 duration = 0, retval, size; 8 struct bpf_insn prog[] = { 9 // BPF_REG_1 - 1st argument: context 10 // BPF_REG_2 - 2nd argument: offset, start at first byte 11 BPF_MOV64_IMM(BPF_REG_2, 0), 12 // BPF_REG_3 - 3rd argument: destination, reserve byte on stack 13 BPF_ALU64_REG(BPF_MOV, BPF_REG_3, BPF_REG_10), 14 BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -1), 15 // BPF_REG_4 - 4th argument: copy one byte 16 BPF_MOV64_IMM(BPF_REG_4, 1), 17 // bpf_skb_load_bytes(ctx, sizeof(pkt_v4), ptr, 1) 18 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, 19 BPF_FUNC_skb_load_bytes), 20 BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2), 21 // if (ret == 0) return BPF_DROP (2) 22 BPF_MOV64_IMM(BPF_REG_0, BPF_DROP), 23 BPF_EXIT_INSN(), 24 // if (ret != 0) return BPF_OK (0) 25 BPF_MOV64_IMM(BPF_REG_0, BPF_OK), 26 BPF_EXIT_INSN(), 27 }; 28 int fd, err; 29 30 /* make sure bpf_skb_load_bytes is not allowed from skb-less context 31 */ 32 fd = bpf_load_program(BPF_PROG_TYPE_FLOW_DISSECTOR, prog, 33 ARRAY_SIZE(prog), "GPL", 0, NULL, 0); 34 CHECK(fd < 0, 35 "flow_dissector-bpf_skb_load_bytes-load", 36 "fd %d errno %d\n", 37 fd, errno); 38 39 err = bpf_prog_test_run(fd, 1, &pkt_v4, sizeof(pkt_v4), 40 &flow_keys, &size, &retval, &duration); 41 CHECK(size != sizeof(flow_keys) || err || retval != 1, 42 "flow_dissector-bpf_skb_load_bytes", 43 "err %d errno %d retval %d duration %d size %u/%zu\n", 44 err, errno, retval, duration, size, sizeof(flow_keys)); 45 46 if (fd >= -1) 47 close(fd); 48 } 49