// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include <network_helpers.h>

void serial_test_flow_dissector_load_bytes(void)
{
        struct bpf_flow_keys flow_keys;
        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;
        LIBBPF_OPTS(bpf_test_run_opts, topts,
                .data_in = &pkt_v4,
                .data_size_in = sizeof(pkt_v4),
                .data_out = &flow_keys,
                .data_size_out = sizeof(flow_keys),
                .repeat = 1,
        );

        /* make sure bpf_skb_load_bytes is not allowed from skb-less context
         */
        fd = bpf_test_load_program(BPF_PROG_TYPE_FLOW_DISSECTOR, prog,
                              ARRAY_SIZE(prog), "GPL", 0, NULL, 0);
        ASSERT_GE(fd, 0, "bpf_test_load_program good fd");

        err = bpf_prog_test_run_opts(fd, &topts);
        ASSERT_OK(err, "test_run");
        ASSERT_EQ(topts.data_size_out, sizeof(flow_keys),
                  "test_run data_size_out");
        ASSERT_EQ(topts.retval, BPF_OK, "test_run retval");

        if (fd >= -1)
                close(fd);
}