mirror of https://gitee.com/openkylin/linux.git
49 lines
1.2 KiB
C
49 lines
1.2 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.
|
||
|
|
*/
|
||
|
|
#include <linux/ip.h>
|
||
|
|
#include <linux/ipv6.h>
|
||
|
|
#include <linux/in.h>
|
||
|
|
#include <linux/tcp.h>
|
||
|
|
#include <linux/udp.h>
|
||
|
|
#include <uapi/linux/bpf.h>
|
||
|
|
#include <net/ip.h>
|
||
|
|
#include "bpf_helpers.h"
|
||
|
|
|
||
|
|
#define DEFAULT_PKTGEN_UDP_PORT 9
|
||
|
|
|
||
|
|
/* 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;
|
||
|
|
};
|
||
|
|
|
||
|
|
SEC("simple")
|
||
|
|
int handle_ingress(struct __sk_buff *skb)
|
||
|
|
{
|
||
|
|
void *data = (void *)(long)skb->data;
|
||
|
|
struct eth_hdr *eth = data;
|
||
|
|
struct iphdr *iph = data + sizeof(*eth);
|
||
|
|
struct udphdr *udp = data + sizeof(*eth) + sizeof(*iph);
|
||
|
|
void *data_end = (void *)(long)skb->data_end;
|
||
|
|
|
||
|
|
/* single length check */
|
||
|
|
if (data + sizeof(*eth) + sizeof(*iph) + sizeof(*udp) > data_end)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
if (eth->h_proto != htons(ETH_P_IP))
|
||
|
|
return 0;
|
||
|
|
if (iph->protocol != IPPROTO_UDP || iph->ihl != 5)
|
||
|
|
return 0;
|
||
|
|
if (ip_is_fragment(iph))
|
||
|
|
return 0;
|
||
|
|
if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT))
|
||
|
|
return TC_ACT_SHOT;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
char _license[] SEC("license") = "GPL";
|