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1/* Copyright (c) 2016 Facebook2 *3 * This program is free software; you can redistribute it and/or4 * modify it under the terms of version 2 of the GNU General Public5 * 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