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// SPDX-License-Identifier: GPL-2.0
#include <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"
#define SAMPLE_SIZE 64ul
#define MAX_CPUS 128
#define bpf_printk(fmt, ...) \
({ \
char ____fmt[] = fmt; \
bpf_trace_printk(____fmt, sizeof(____fmt), \
##__VA_ARGS__); \
})
struct bpf_map_def SEC("maps") my_map = {
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(u32),
.max_entries = MAX_CPUS,
};
SEC("xdp_sample")
int xdp_sample_prog(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
/* Metadata will be in the perf event before the packet data. */
struct S {
u16 cookie;
u16 pkt_len;
} __packed metadata;
if (data < data_end) {
/* The XDP perf_event_output handler will use the upper 32 bits
* of the flags argument as a number of bytes to include of the
* packet payload in the event data. If the size is too big, the
* call to bpf_perf_event_output will fail and return -EFAULT.
*
* See bpf_xdp_event_output in net/core/filter.c.
*
* The BPF_F_CURRENT_CPU flag means that the event output fd
* will be indexed by the CPU number in the event map.
*/
u64 flags = BPF_F_CURRENT_CPU;
u16 sample_size;
int ret;
metadata.cookie = 0xdead;
metadata.pkt_len = (u16)(data_end - data);
sample_size = min(metadata.pkt_len, SAMPLE_SIZE);
flags |= (u64)sample_size << 32;
ret = bpf_perf_event_output(ctx, &my_map, flags,
&metadata, sizeof(metadata));
if (ret)
bpf_printk("perf_event_output failed: %d\n", ret);
}
return XDP_PASS;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;
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