72 lines
1.8 KiB
C
72 lines
1.8 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Facebook */
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#include <linux/stddef.h>
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <../../../tools/include/linux/filter.h>
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char _license[] SEC("license") = "GPL";
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struct args {
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__u64 log_buf;
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__u32 log_size;
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int max_entries;
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int map_fd;
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int prog_fd;
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};
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SEC("syscall")
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int bpf_prog(struct args *ctx)
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{
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static char license[] = "GPL";
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static struct bpf_insn insns[] = {
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BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
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BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
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BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
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BPF_LD_MAP_FD(BPF_REG_1, 0),
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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static union bpf_attr map_create_attr = {
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.map_type = BPF_MAP_TYPE_HASH,
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.key_size = 8,
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.value_size = 8,
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};
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static union bpf_attr map_update_attr = { .map_fd = 1, };
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static __u64 key = 12;
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static __u64 value = 34;
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static union bpf_attr prog_load_attr = {
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.prog_type = BPF_PROG_TYPE_XDP,
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.insn_cnt = sizeof(insns) / sizeof(insns[0]),
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};
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int ret;
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map_create_attr.max_entries = ctx->max_entries;
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prog_load_attr.license = (long) license;
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prog_load_attr.insns = (long) insns;
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prog_load_attr.log_buf = ctx->log_buf;
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prog_load_attr.log_size = ctx->log_size;
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prog_load_attr.log_level = 1;
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ret = bpf_sys_bpf(BPF_MAP_CREATE, &map_create_attr, sizeof(map_create_attr));
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if (ret <= 0)
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return ret;
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ctx->map_fd = ret;
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insns[3].imm = ret;
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map_update_attr.map_fd = ret;
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map_update_attr.key = (long) &key;
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map_update_attr.value = (long) &value;
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ret = bpf_sys_bpf(BPF_MAP_UPDATE_ELEM, &map_update_attr, sizeof(map_update_attr));
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if (ret < 0)
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return ret;
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ret = bpf_sys_bpf(BPF_PROG_LOAD, &prog_load_attr, sizeof(prog_load_attr));
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if (ret <= 0)
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return ret;
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ctx->prog_fd = ret;
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return 1;
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}
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