1 /* Copyright (c) 2016 Facebook
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
7 #define KBUILD_MODNAME "foo"
9 #include <linux/ipv6.h>
11 #include <linux/tcp.h>
12 #include <linux/udp.h>
13 #include <uapi/linux/bpf.h>
14 #include "bpf_helpers.h"
16 #define DEFAULT_PKTGEN_UDP_PORT 9
18 #define IP_OFFSET 0x1FFF
20 static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff)
22 return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off))
23 & (IP_MF | IP_OFFSET);
27 int handle_ingress(struct __sk_buff *skb)
29 __u64 troff = ETH_HLEN + sizeof(struct iphdr);
31 if (load_half(skb, offsetof(struct ethhdr, h_proto)) != ETH_P_IP)
33 if (load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)) != IPPROTO_UDP ||
34 load_byte(skb, ETH_HLEN) != 0x45)
36 if (ip_is_fragment(skb, ETH_HLEN))
38 if (load_half(skb, troff + offsetof(struct udphdr, dest)) == DEFAULT_PKTGEN_UDP_PORT)
42 char _license[] SEC("license") = "GPL";