| /* 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 <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 "bpf_helpers.h" | |
| #define DEFAULT_PKTGEN_UDP_PORT 9 | |
| #define IP_MF 0x2000 | |
| #define IP_OFFSET 0x1FFF | |
| static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff) | |
| { | |
| return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off)) | |
| & (IP_MF | IP_OFFSET); | |
| } | |
| SEC("ldabs") | |
| int handle_ingress(struct __sk_buff *skb) | |
| { | |
| __u64 troff = ETH_HLEN + sizeof(struct iphdr); | |
| if (load_half(skb, offsetof(struct ethhdr, h_proto)) != ETH_P_IP) | |
| return 0; | |
| if (load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)) != IPPROTO_UDP || | |
| load_byte(skb, ETH_HLEN) != 0x45) | |
| return 0; | |
| if (ip_is_fragment(skb, ETH_HLEN)) | |
| return 0; | |
| if (load_half(skb, troff + offsetof(struct udphdr, dest)) == DEFAULT_PKTGEN_UDP_PORT) | |
| return TC_ACT_SHOT; | |
| return 0; | |
| } | |
| char _license[] SEC("license") = "GPL"; |