1// SPDX-License-Identifier: GPL-2.0
 2#include <inttypes.h>
 3#include <linux/bpf.h>
 4#include <bpf/bpf_endian.h>
 5#include <bpf/bpf_helpers.h>
 6#include <linux/if_ether.h>
 7#include <linux/ip.h>
 8
 9/* This function extracts the last byte of the daddr, and uses it
10 * as output dev index.
11 */
12SEC("lwt_xmit")
13int test_lwt_reroute(struct __sk_buff *skb)
14{
15	struct iphdr *iph = NULL;
16	void *start = (void *)(long)skb->data;
17	void *end = (void *)(long)skb->data_end;
18
19	/* set mark at most once */
20	if (skb->mark != 0)
21		return BPF_OK;
22
23	if (start + sizeof(*iph) > end)
24		return BPF_DROP;
25
26	iph = (struct iphdr *)start;
27	skb->mark = bpf_ntohl(iph->daddr) & 0xff;
28
29	/* do not reroute x.x.x.0 packets */
30	if (skb->mark == 0)
31		return BPF_OK;
32
33	return BPF_LWT_REROUTE;
34}
35
36char _license[] SEC("license") = "GPL";

 1// SPDX-License-Identifier: GPL-2.0
 2#include <inttypes.h>
 3#include <linux/bpf.h>
 4#include <bpf/bpf_endian.h>
 5#include <bpf/bpf_helpers.h>
 6#include <linux/if_ether.h>
 7#include <linux/ip.h>
 8
 9/* This function extracts the last byte of the daddr, and uses it
10 * as output dev index.
11 */
12SEC("lwt_xmit")
13int test_lwt_reroute(struct __sk_buff *skb)
14{
15	struct iphdr *iph = NULL;
16	void *start = (void *)(long)skb->data;
17	void *end = (void *)(long)skb->data_end;
18
19	/* set mark at most once */
20	if (skb->mark != 0)
21		return BPF_OK;
22
23	if (start + sizeof(*iph) > end)
24		return BPF_DROP;
25
26	iph = (struct iphdr *)start;
27	skb->mark = bpf_ntohl(iph->daddr) & 0xff;
28
29	/* do not reroute x.x.x.0 packets */
30	if (skb->mark == 0)
31		return BPF_OK;
32
33	return BPF_LWT_REROUTE;
34}
35
36char _license[] SEC("license") = "GPL";