blob: 1021687b7f2d144881c1d2fa641e817a9467a5f4 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
// ingress.c
#include <vmlinux.h>
#include <bpf/bpf_endian.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#define TC_ACT_OK 0
#define ETH_P_IP 0x0800 /* Internet Protocol packet */
/// @tchook {"ifindex":2, "attach_point":"BPF_TC_INGRESS"}
/// @tcopts {"handle":1, "priority":1}
SEC("tc")
int tc_ingress(struct __sk_buff *ctx) {
void *data_end = (void *)(__u64)ctx->data_end;
void *data = (void *)(__u64)ctx->data;
struct ethhdr *l2;
struct iphdr *l3;
if (ctx->protocol != bpf_htons(ETH_P_IP))
return TC_ACT_OK;
l2 = data;
if ((void *)(l2 + 1) > data_end)
return TC_ACT_OK;
l3 = (struct iphdr *)(l2 + 1);
if ((void *)(l3 + 1) > data_end)
return TC_ACT_OK;
bpf_printk("Got IP packet: tot_len: %d, ttl: %d", bpf_ntohs(l3->tot_len),
l3->ttl);
return TC_ACT_OK;
}
char __license[] SEC("license") = "GPL";
|