18c2ecf20Sopenharmony_ci/* Copyright (c) 2016 Facebook 28c2ecf20Sopenharmony_ci * 38c2ecf20Sopenharmony_ci * This program is free software; you can redistribute it and/or 48c2ecf20Sopenharmony_ci * modify it under the terms of version 2 of the GNU General Public 58c2ecf20Sopenharmony_ci * License as published by the Free Software Foundation. 68c2ecf20Sopenharmony_ci */ 78c2ecf20Sopenharmony_ci#define KBUILD_MODNAME "foo" 88c2ecf20Sopenharmony_ci#include <linux/ip.h> 98c2ecf20Sopenharmony_ci#include <linux/ipv6.h> 108c2ecf20Sopenharmony_ci#include <linux/in.h> 118c2ecf20Sopenharmony_ci#include <linux/tcp.h> 128c2ecf20Sopenharmony_ci#include <linux/udp.h> 138c2ecf20Sopenharmony_ci#include <uapi/linux/bpf.h> 148c2ecf20Sopenharmony_ci#include <bpf/bpf_helpers.h> 158c2ecf20Sopenharmony_ci#include "bpf_legacy.h" 168c2ecf20Sopenharmony_ci 178c2ecf20Sopenharmony_ci#define DEFAULT_PKTGEN_UDP_PORT 9 188c2ecf20Sopenharmony_ci#define IP_MF 0x2000 198c2ecf20Sopenharmony_ci#define IP_OFFSET 0x1FFF 208c2ecf20Sopenharmony_ci 218c2ecf20Sopenharmony_cistatic inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff) 228c2ecf20Sopenharmony_ci{ 238c2ecf20Sopenharmony_ci return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off)) 248c2ecf20Sopenharmony_ci & (IP_MF | IP_OFFSET); 258c2ecf20Sopenharmony_ci} 268c2ecf20Sopenharmony_ci 278c2ecf20Sopenharmony_ciSEC("ldabs") 288c2ecf20Sopenharmony_ciint handle_ingress(struct __sk_buff *skb) 298c2ecf20Sopenharmony_ci{ 308c2ecf20Sopenharmony_ci __u64 troff = ETH_HLEN + sizeof(struct iphdr); 318c2ecf20Sopenharmony_ci 328c2ecf20Sopenharmony_ci if (load_half(skb, offsetof(struct ethhdr, h_proto)) != ETH_P_IP) 338c2ecf20Sopenharmony_ci return 0; 348c2ecf20Sopenharmony_ci if (load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)) != IPPROTO_UDP || 358c2ecf20Sopenharmony_ci load_byte(skb, ETH_HLEN) != 0x45) 368c2ecf20Sopenharmony_ci return 0; 378c2ecf20Sopenharmony_ci if (ip_is_fragment(skb, ETH_HLEN)) 388c2ecf20Sopenharmony_ci return 0; 398c2ecf20Sopenharmony_ci if (load_half(skb, troff + offsetof(struct udphdr, dest)) == DEFAULT_PKTGEN_UDP_PORT) 408c2ecf20Sopenharmony_ci return TC_ACT_SHOT; 418c2ecf20Sopenharmony_ci return 0; 428c2ecf20Sopenharmony_ci} 438c2ecf20Sopenharmony_cichar _license[] SEC("license") = "GPL"; 44