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43 lines
1.2 KiB
43 lines
1.2 KiB
/* Copyright (c) 2016 Facebook |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of version 2 of the GNU General Public |
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* License as published by the Free Software Foundation. |
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*/ |
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#define KBUILD_MODNAME "foo" |
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#include <linux/ip.h> |
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#include <linux/ipv6.h> |
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#include <linux/in.h> |
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#include <linux/tcp.h> |
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#include <linux/udp.h> |
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#include <uapi/linux/bpf.h> |
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#include <bpf/bpf_helpers.h> |
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#include "bpf_legacy.h" |
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#define DEFAULT_PKTGEN_UDP_PORT 9 |
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#define IP_MF 0x2000 |
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#define IP_OFFSET 0x1FFF |
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static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff) |
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{ |
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return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off)) |
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& (IP_MF | IP_OFFSET); |
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} |
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SEC("ldabs") |
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int handle_ingress(struct __sk_buff *skb) |
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{ |
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__u64 troff = ETH_HLEN + sizeof(struct iphdr); |
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if (load_half(skb, offsetof(struct ethhdr, h_proto)) != ETH_P_IP) |
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return 0; |
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if (load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)) != IPPROTO_UDP || |
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load_byte(skb, ETH_HLEN) != 0x45) |
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return 0; |
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if (ip_is_fragment(skb, ETH_HLEN)) |
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return 0; |
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if (load_half(skb, troff + offsetof(struct udphdr, dest)) == DEFAULT_PKTGEN_UDP_PORT) |
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return TC_ACT_SHOT; |
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return 0; |
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} |
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char _license[] SEC("license") = "GPL";
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