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