1 /* Copyright (c) 2016 Facebook 1 /* Copyright (c) 2016 Facebook
2 * 2 *
3 * This program is free software; you can redi 3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of t 4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software F 5 * License as published by the Free Software Foundation.
6 */ 6 */
7 #define KBUILD_MODNAME "foo" 7 #define KBUILD_MODNAME "foo"
8 #include <linux/ip.h> 8 #include <linux/ip.h>
9 #include <linux/ipv6.h> 9 #include <linux/ipv6.h>
10 #include <linux/in.h> 10 #include <linux/in.h>
11 #include <linux/tcp.h> 11 #include <linux/tcp.h>
12 #include <linux/udp.h> 12 #include <linux/udp.h>
13 #include <uapi/linux/bpf.h> 13 #include <uapi/linux/bpf.h>
14 #include <bpf/bpf_helpers.h> 14 #include <bpf/bpf_helpers.h>
15 #include "bpf_legacy.h" 15 #include "bpf_legacy.h"
16 16
17 #define DEFAULT_PKTGEN_UDP_PORT 9 17 #define DEFAULT_PKTGEN_UDP_PORT 9
18 #define IP_MF 0x2000 18 #define IP_MF 0x2000
19 #define IP_OFFSET 0x1FFF 19 #define IP_OFFSET 0x1FFF
20 20
21 static inline int ip_is_fragment(struct __sk_b 21 static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff)
22 { 22 {
23 return load_half(ctx, nhoff + offsetof 23 return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off))
24 & (IP_MF | IP_OFFSET); 24 & (IP_MF | IP_OFFSET);
25 } 25 }
26 26
27 SEC("ldabs") 27 SEC("ldabs")
28 int handle_ingress(struct __sk_buff *skb) 28 int handle_ingress(struct __sk_buff *skb)
29 { 29 {
30 __u64 troff = ETH_HLEN + sizeof(struct 30 __u64 troff = ETH_HLEN + sizeof(struct iphdr);
31 31
32 if (load_half(skb, offsetof(struct eth 32 if (load_half(skb, offsetof(struct ethhdr, h_proto)) != ETH_P_IP)
33 return 0; 33 return 0;
34 if (load_byte(skb, ETH_HLEN + offsetof 34 if (load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)) != IPPROTO_UDP ||
35 load_byte(skb, ETH_HLEN) != 0x45) 35 load_byte(skb, ETH_HLEN) != 0x45)
36 return 0; 36 return 0;
37 if (ip_is_fragment(skb, ETH_HLEN)) 37 if (ip_is_fragment(skb, ETH_HLEN))
38 return 0; 38 return 0;
39 if (load_half(skb, troff + offsetof(st 39 if (load_half(skb, troff + offsetof(struct udphdr, dest)) == DEFAULT_PKTGEN_UDP_PORT)
40 return TC_ACT_SHOT; 40 return TC_ACT_SHOT;
41 return 0; 41 return 0;
42 } 42 }
43 char _license[] SEC("license") = "GPL"; 43 char _license[] SEC("license") = "GPL";
44 44
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