1/* Copyright (c) 2016 Facebook
 2 *
 3 * This program is free software; you can redistribute it and/or
 4 * modify it under the terms of version 2 of the GNU General Public
 5 * License as published by the Free Software Foundation.
 6 */
 7#define KBUILD_MODNAME "foo"
 8#include <uapi/linux/if_ether.h>
 9#include <uapi/linux/in6.h>
10#include <uapi/linux/ipv6.h>
11#include <uapi/linux/pkt_cls.h>
12#include <uapi/linux/bpf.h>
13#include "bpf_helpers.h"
14
15/* copy of 'struct ethhdr' without __packed */
16struct eth_hdr {
17	unsigned char   h_dest[ETH_ALEN];
18	unsigned char   h_source[ETH_ALEN];
19	unsigned short  h_proto;
20};
21
22#define PIN_GLOBAL_NS		2
23struct bpf_elf_map {
24	__u32 type;
25	__u32 size_key;
26	__u32 size_value;
27	__u32 max_elem;
28	__u32 flags;
29	__u32 id;
30	__u32 pinning;
31};
32
33struct bpf_elf_map SEC("maps") test_cgrp2_array_pin = {
34	.type		= BPF_MAP_TYPE_CGROUP_ARRAY,
35	.size_key	= sizeof(uint32_t),
36	.size_value	= sizeof(uint32_t),
37	.pinning	= PIN_GLOBAL_NS,
38	.max_elem	= 1,
39};
40
41SEC("filter")
42int handle_egress(struct __sk_buff *skb)
43{
44	void *data = (void *)(long)skb->data;
45	struct eth_hdr *eth = data;
46	struct ipv6hdr *ip6h = data + sizeof(*eth);
47	void *data_end = (void *)(long)skb->data_end;
48	char dont_care_msg[] = "dont care %04x %d\n";
49	char pass_msg[] = "pass\n";
50	char reject_msg[] = "reject\n";
51
52	/* single length check */
53	if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
54		return TC_ACT_OK;
55
56	if (eth->h_proto != htons(ETH_P_IPV6) ||
57	    ip6h->nexthdr != IPPROTO_ICMPV6) {
58		bpf_trace_printk(dont_care_msg, sizeof(dont_care_msg),
59				 eth->h_proto, ip6h->nexthdr);
60		return TC_ACT_OK;
61	} else if (bpf_skb_under_cgroup(skb, &test_cgrp2_array_pin, 0) != 1) {
62		bpf_trace_printk(pass_msg, sizeof(pass_msg));
63		return TC_ACT_OK;
64	} else {
65		bpf_trace_printk(reject_msg, sizeof(reject_msg));
66		return TC_ACT_SHOT;
67	}
68}
69
70char _license[] SEC("license") = "GPL";