// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <linux/pkt_cls.h>
#include <linux/if_ether.h>
#include <linux/in.h>
#include <linux/ipv6.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>

#define ctx_ptr(field)          ((void *)(long)(field))

volatile __u32 phys_ifindex;

SEC("tc/ingress")
int nk_primary_rx_redirect(struct __sk_buff *skb)
{
        void *data_end = ctx_ptr(skb->data_end);
        void *data = ctx_ptr(skb->data);
        struct ethhdr *eth;
        struct ipv6hdr *ip6h;

        eth = data;
        if ((void *)(eth + 1) > data_end)
                return TC_ACT_OK;

        if (eth->h_proto != bpf_htons(ETH_P_IPV6))
                return TC_ACT_OK;

        ip6h = data + sizeof(struct ethhdr);
        if ((void *)(ip6h + 1) > data_end)
                return TC_ACT_OK;

        if (ip6h->nexthdr == IPPROTO_ICMPV6)
                return TC_ACT_OK;

        return bpf_redirect_neigh(phys_ifindex, NULL, 0, 0);
}

char __license[] SEC("license") = "GPL";