projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 65d472fb AS |
1 | /* Copyright (c) 2016 Facebook |
| 2 | * | |
| 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. | |
| 6 | */ | |
| 96a8eb1e | 7 | #define KBUILD_MODNAME "foo" |
| 65d472fb AS |
8 | #include <linux/ip.h> |
| 9 | #include <linux/ipv6.h> | |
| 10 | #include <linux/in.h> | |
| 11 | #include <linux/tcp.h> | |
| 12 | #include <linux/udp.h> | |
| 13 | #include <uapi/linux/bpf.h> | |
| 7cf245a3 | 14 | #include <bpf/bpf_helpers.h> |
| 36b5d471 | 15 | #include "bpf_legacy.h" |
| 65d472fb AS |
16 | |
| 17 | #define DEFAULT_PKTGEN_UDP_PORT 9 | |
| 18 | #define IP_MF 0x2000 | |
| 19 | #define IP_OFFSET 0x1FFF | |
| 20 | ||
| 21 | static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff) | |
| 22 | { | |
| 23 | return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off)) | |
| 24 | & (IP_MF | IP_OFFSET); | |
| 25 | } | |
| 26 | ||
| 27 | SEC("ldabs") | |
| 28 | int handle_ingress(struct __sk_buff *skb) | |
| 29 | { | |
| 30 | __u64 troff = ETH_HLEN + sizeof(struct iphdr); | |
| 31 | ||
| 32 | if (load_half(skb, offsetof(struct ethhdr, h_proto)) != ETH_P_IP) | |
| 33 | return 0; | |
| 34 | if (load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)) != IPPROTO_UDP || | |
| 35 | load_byte(skb, ETH_HLEN) != 0x45) | |
| 36 | return 0; | |
| 37 | if (ip_is_fragment(skb, ETH_HLEN)) | |
| 38 | return 0; | |
| 39 | if (load_half(skb, troff + offsetof(struct udphdr, dest)) == DEFAULT_PKTGEN_UDP_PORT) | |
| 40 | return TC_ACT_SHOT; | |
| 41 | return 0; | |
| 42 | } | |
| 43 | char _license[] SEC("license") = "GPL"; |