1#include <linux/bpf.h>
 2#include "bpf_helpers.h"
 3#include "bpf_util.h"
 4#include "bpf_endian.h"
 5
 6int _version SEC("version") = 1;
 7
 8#define bpf_printk(fmt, ...)					\
 9({								\
10	       char ____fmt[] = fmt;				\
11	       bpf_trace_printk(____fmt, sizeof(____fmt),	\
12				##__VA_ARGS__);			\
13})
14
15SEC("sk_msg1")
16int bpf_prog1(struct sk_msg_md *msg)
17{
18	void *data_end = (void *)(long) msg->data_end;
19	void *data = (void *)(long) msg->data;
20
21	char *d;
22
23	if (data + 8 > data_end)
24		return SK_DROP;
25
26	bpf_printk("data length %i\n", (__u64)msg->data_end - (__u64)msg->data);
27	d = (char *)data;
28	bpf_printk("hello sendmsg hook %i %i\n", d[0], d[1]);
29
30	return SK_PASS;
31}
32
33char _license[] SEC("license") = "GPL";