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 "vmlinux.h"
9#include "net_shared.h"
10#include <bpf/bpf_helpers.h>
11
12/* copy of 'struct ethhdr' without __packed */
13struct eth_hdr {
14	unsigned char   h_dest[ETH_ALEN];
15	unsigned char   h_source[ETH_ALEN];
16	unsigned short  h_proto;
17};
18
19struct {
20	__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
21	__type(key, u32);
22	__type(value, u32);
23	__uint(pinning, LIBBPF_PIN_BY_NAME);
24	__uint(max_entries, 1);
25} test_cgrp2_array_pin SEC(".maps");
26
27SEC("filter")
28int handle_egress(struct __sk_buff *skb)
29{
30	void *data = (void *)(long)skb->data;
31	struct eth_hdr *eth = data;
32	struct ipv6hdr *ip6h = data + sizeof(*eth);
33	void *data_end = (void *)(long)skb->data_end;
34	char dont_care_msg[] = "dont care %04x %d\n";
35	char pass_msg[] = "pass\n";
36	char reject_msg[] = "reject\n";
37
38	/* single length check */
39	if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
40		return TC_ACT_OK;
41
42	if (eth->h_proto != bpf_htons(ETH_P_IPV6) ||
43	    ip6h->nexthdr != IPPROTO_ICMPV6) {
44		bpf_trace_printk(dont_care_msg, sizeof(dont_care_msg),
45				 eth->h_proto, ip6h->nexthdr);
46		return TC_ACT_OK;
47	} else if (bpf_skb_under_cgroup(skb, &test_cgrp2_array_pin, 0) != 1) {
48		bpf_trace_printk(pass_msg, sizeof(pass_msg));
49		return TC_ACT_OK;
50	} else {
51		bpf_trace_printk(reject_msg, sizeof(reject_msg));
52		return TC_ACT_SHOT;
53	}
54}
55
56char _license[] SEC("license") = "GPL";
57