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/* Copyright (c) 2016 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#define KBUILD_MODNAME "foo"
#include <uapi/linux/if_ether.h>
#include <uapi/linux/in6.h>
#include <uapi/linux/ipv6.h>
#include <uapi/linux/pkt_cls.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"
/* copy of 'struct ethhdr' without __packed */
struct eth_hdr {
unsigned char h_dest[ETH_ALEN];
unsigned char h_source[ETH_ALEN];
unsigned short h_proto;
};
#define PIN_GLOBAL_NS 2
struct bpf_elf_map {
__u32 type;
__u32 size_key;
__u32 size_value;
__u32 max_elem;
__u32 flags;
__u32 id;
__u32 pinning;
};
struct bpf_elf_map SEC("maps") test_cgrp2_array_pin = {
.type = BPF_MAP_TYPE_CGROUP_ARRAY,
.size_key = sizeof(uint32_t),
.size_value = sizeof(uint32_t),
.pinning = PIN_GLOBAL_NS,
.max_elem = 1,
};
SEC("filter")
int handle_egress(struct __sk_buff *skb)
{
void *data = (void *)(long)skb->data;
struct eth_hdr *eth = data;
struct ipv6hdr *ip6h = data + sizeof(*eth);
void *data_end = (void *)(long)skb->data_end;
char dont_care_msg[] = "dont care %04x %d\n";
char pass_msg[] = "pass\n";
char reject_msg[] = "reject\n";
/* single length check */
if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
return TC_ACT_OK;
if (eth->h_proto != htons(ETH_P_IPV6) ||
ip6h->nexthdr != IPPROTO_ICMPV6) {
bpf_trace_printk(dont_care_msg, sizeof(dont_care_msg),
eth->h_proto, ip6h->nexthdr);
return TC_ACT_OK;
} else if (bpf_skb_under_cgroup(skb, &test_cgrp2_array_pin, 0) != 1) {
bpf_trace_printk(pass_msg, sizeof(pass_msg));
return TC_ACT_OK;
} else {
bpf_trace_printk(reject_msg, sizeof(reject_msg));
return TC_ACT_SHOT;
}
}
char _license[] SEC("license") = "GPL";
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