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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 "vmlinux.h"
#include "net_shared.h"
#include <bpf/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;
};
struct {
__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
__type(key, u32);
__type(value, u32);
__uint(pinning, LIBBPF_PIN_BY_NAME);
__uint(max_entries, 1);
} test_cgrp2_array_pin SEC(".maps");
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 != bpf_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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