| /* 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 bpf_map_def __attribute__ ((section("maps"), used)) map_in = { |
| .type = MAP_TYPE, |
| .key_size = 0, |
| .value_size = sizeof(__u32), |
| .max_entries = 32, |
| .map_flags = 0, |
| }; |
| |
| struct bpf_map_def __attribute__ ((section("maps"), used)) map_out = { |
| .type = MAP_TYPE, |
| .key_size = 0, |
| .value_size = sizeof(__u32), |
| .max_entries = 32, |
| .map_flags = 0, |
| }; |
| |
| 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"; |