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// SPDX-License-Identifier: GPL-2.0
#include <inttypes.h>
#include <linux/bpf.h>
#include <bpf/bpf_endian.h>
#include <bpf/bpf_helpers.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
/* This function extracts the last byte of the daddr, and uses it
* as output dev index.
*/
SEC("lwt_xmit")
int test_lwt_reroute(struct __sk_buff *skb)
{
struct iphdr *iph = NULL;
void *start = (void *)(long)skb->data;
void *end = (void *)(long)skb->data_end;
/* set mark at most once */
if (skb->mark != 0)
return BPF_OK;
if (start + sizeof(*iph) > end)
return BPF_DROP;
iph = (struct iphdr *)start;
skb->mark = bpf_ntohl(iph->daddr) & 0xff;
/* do not reroute x.x.x.0 packets */
if (skb->mark == 0)
return BPF_OK;
return BPF_LWT_REROUTE;
}
char _license[] SEC("license") = "GPL";
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