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57 lines
1.5 KiB
57 lines
1.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/ptrace.h> |
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#include <linux/version.h> |
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#include <uapi/linux/bpf.h> |
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#include <bpf/bpf_helpers.h> |
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#define SAMPLE_SIZE 64ul |
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struct { |
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__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); |
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__uint(key_size, sizeof(int)); |
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__uint(value_size, sizeof(u32)); |
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} my_map SEC(".maps"); |
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SEC("xdp_sample") |
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int xdp_sample_prog(struct xdp_md *ctx) |
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{ |
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void *data_end = (void *)(long)ctx->data_end; |
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void *data = (void *)(long)ctx->data; |
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/* Metadata will be in the perf event before the packet data. */ |
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struct S { |
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u16 cookie; |
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u16 pkt_len; |
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} __packed metadata; |
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if (data < data_end) { |
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/* The XDP perf_event_output handler will use the upper 32 bits |
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* of the flags argument as a number of bytes to include of the |
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* packet payload in the event data. If the size is too big, the |
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* call to bpf_perf_event_output will fail and return -EFAULT. |
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* |
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* See bpf_xdp_event_output in net/core/filter.c. |
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* |
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* The BPF_F_CURRENT_CPU flag means that the event output fd |
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* will be indexed by the CPU number in the event map. |
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*/ |
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u64 flags = BPF_F_CURRENT_CPU; |
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u16 sample_size; |
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int ret; |
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metadata.cookie = 0xdead; |
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metadata.pkt_len = (u16)(data_end - data); |
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sample_size = min(metadata.pkt_len, SAMPLE_SIZE); |
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flags |= (u64)sample_size << 32; |
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ret = bpf_perf_event_output(ctx, &my_map, flags, |
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&metadata, sizeof(metadata)); |
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if (ret) |
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bpf_printk("perf_event_output failed: %d\n", ret); |
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} |
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return XDP_PASS; |
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} |
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char _license[] SEC("license") = "GPL"; |
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u32 _version SEC("version") = LINUX_VERSION_CODE;
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