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1e54ad25 THJ |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/ptrace.h> | |
3 | #include <linux/version.h> | |
4 | #include <uapi/linux/bpf.h> | |
5 | #include "bpf_helpers.h" | |
6 | ||
7 | #define SAMPLE_SIZE 64ul | |
8 | #define MAX_CPUS 128 | |
9 | ||
1e54ad25 THJ |
10 | struct bpf_map_def SEC("maps") my_map = { |
11 | .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, | |
12 | .key_size = sizeof(int), | |
13 | .value_size = sizeof(u32), | |
14 | .max_entries = MAX_CPUS, | |
15 | }; | |
16 | ||
17 | SEC("xdp_sample") | |
18 | int xdp_sample_prog(struct xdp_md *ctx) | |
19 | { | |
20 | void *data_end = (void *)(long)ctx->data_end; | |
21 | void *data = (void *)(long)ctx->data; | |
22 | ||
23 | /* Metadata will be in the perf event before the packet data. */ | |
24 | struct S { | |
25 | u16 cookie; | |
26 | u16 pkt_len; | |
27 | } __packed metadata; | |
28 | ||
29 | if (data < data_end) { | |
30 | /* The XDP perf_event_output handler will use the upper 32 bits | |
31 | * of the flags argument as a number of bytes to include of the | |
32 | * packet payload in the event data. If the size is too big, the | |
33 | * call to bpf_perf_event_output will fail and return -EFAULT. | |
34 | * | |
35 | * See bpf_xdp_event_output in net/core/filter.c. | |
36 | * | |
37 | * The BPF_F_CURRENT_CPU flag means that the event output fd | |
38 | * will be indexed by the CPU number in the event map. | |
39 | */ | |
40 | u64 flags = BPF_F_CURRENT_CPU; | |
41 | u16 sample_size; | |
42 | int ret; | |
43 | ||
44 | metadata.cookie = 0xdead; | |
45 | metadata.pkt_len = (u16)(data_end - data); | |
46 | sample_size = min(metadata.pkt_len, SAMPLE_SIZE); | |
47 | flags |= (u64)sample_size << 32; | |
48 | ||
49 | ret = bpf_perf_event_output(ctx, &my_map, flags, | |
50 | &metadata, sizeof(metadata)); | |
51 | if (ret) | |
52 | bpf_printk("perf_event_output failed: %d\n", ret); | |
53 | } | |
54 | ||
55 | return XDP_PASS; | |
56 | } | |
57 | ||
58 | char _license[] SEC("license") = "GPL"; | |
59 | u32 _version SEC("version") = LINUX_VERSION_CODE; |