/* SPDX-License-Identifier: GPL-2.0 */ // Copyright (c) 2018 Politecnico di Torino #include <stddef.h> #include <string.h> #include <linux/bpf.h> #include <linux/if_ether.h> #include <linux/ip.h> #include <linux/pkt_cls.h> #include "bpf_helpers.h" int _version SEC("version") = 1; struct { __uint(type, MAP_TYPE); __uint(max_entries, 32); __uint(map_flags, 0); __uint(key_size, 0); __uint(value_size, sizeof(__u32)); } map_in SEC(".maps"); struct { __uint(type, MAP_TYPE); __uint(max_entries, 32); __uint(map_flags, 0); __uint(key_size, 0); __uint(value_size, sizeof(__u32)); } map_out SEC(".maps"); SEC("test") int _test(struct __sk_buff *skb) { void *data_end = (void *)(long)skb->data_end; void *data = (void *)(long)skb->data; struct ethhdr *eth = (struct ethhdr *)(data); __u32 value; int err; if (eth + 1 > data_end) return TC_ACT_SHOT; struct iphdr *iph = (struct iphdr *)(eth + 1); if (iph + 1 > data_end) return TC_ACT_SHOT; err = bpf_map_pop_elem(&map_in, &value); if (err) return TC_ACT_SHOT; iph->daddr = value; err = bpf_map_push_elem(&map_out, &iph->saddr, 0); if (err) return TC_ACT_SHOT; return TC_ACT_OK; } char _license[] SEC("license") = "GPL";