af_xdp_kern.c

/* SPDX-License-Identifier: GPL-2.0 */

#include <linux/bpf.h>
#include <linux/in.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>

#include "../common/parsing_helpers.h"

struct {
	__uint(type, BPF_MAP_TYPE_XSKMAP);
	__type(key, __u32);
	__type(value, __u32);
	__uint(max_entries, 64);
} xsks_map SEC(".maps");

SEC("xdp")
int xdp_sock_prog(struct xdp_md *ctx)
{
    void *data = (void *)(long)ctx->data;
    void *data_end = (void *)(long)ctx->data_end;
    struct ethhdr *eth = data;
    __u64 offset = sizeof(*eth);

    if ((void *)eth + offset > data_end){
	    return 0;
    }

    if(bpf_ntohs(eth->h_proto)!=5401) {
    	return XDP_PASS;
    }

    return bpf_redirect_map(&xsks_map, ctx->rx_queue_index, XDP_PASS);
}

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