bpf/progs/test_queue_stack_map.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 // Copyright (c) 2018 Politecnico di Torino
0003 #include <stddef.h>
0004 #include <string.h>
0005 #include <linux/bpf.h>
0006 #include <linux/if_ether.h>
0007 #include <linux/ip.h>
0008 #include <linux/pkt_cls.h>
0009 #include <bpf/bpf_helpers.h>
0010
0011 struct {
0012     __uint(type, MAP_TYPE);
0013     __uint(max_entries, 32);
0014     __uint(map_flags, 0);
0015     __uint(key_size, 0);
0016     __uint(value_size, sizeof(__u32));
0017 } map_in SEC(".maps");
0018
0019 struct {
0020     __uint(type, MAP_TYPE);
0021     __uint(max_entries, 32);
0022     __uint(map_flags, 0);
0023     __uint(key_size, 0);
0024     __uint(value_size, sizeof(__u32));
0025 } map_out SEC(".maps");
0026
0027 SEC("tc")
0028 int _test(struct __sk_buff *skb)
0029 {
0030     void *data_end = (void *)(long)skb->data_end;
0031     void *data = (void *)(long)skb->data;
0032     struct ethhdr *eth = (struct ethhdr *)(data);
0033     __u32 value;
0034     int err;
0035
0036     if (eth + 1 > data_end)
0037         return TC_ACT_SHOT;
0038
0039     struct iphdr *iph = (struct iphdr *)(eth + 1);
0040
0041     if (iph + 1 > data_end)
0042         return TC_ACT_SHOT;
0043
0044     err = bpf_map_pop_elem(&map_in, &value);
0045     if (err)
0046         return TC_ACT_SHOT;
0047
0048     iph->daddr = value;
0049
0050     err = bpf_map_push_elem(&map_out, &iph->saddr, 0);
0051     if (err)
0052         return TC_ACT_SHOT;
0053
0054     return TC_ACT_OK;
0055 }
0056
0057 char _license[] SEC("license") = "GPL";