71 строка
1.8 KiB
C
71 строка
1.8 KiB
C
/* 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/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";
|