58 lines
1.5 KiB
C
58 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/ptrace.h>
|
|
#include <linux/version.h>
|
|
#include <uapi/linux/bpf.h>
|
|
#include <bpf/bpf_helpers.h>
|
|
|
|
#define SAMPLE_SIZE 64ul
|
|
|
|
struct {
|
|
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
|
|
__uint(key_size, sizeof(int));
|
|
__uint(value_size, sizeof(u32));
|
|
} my_map SEC(".maps");
|
|
|
|
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;
|