projects / mirror_ubuntu-artful-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 6882804c AS |
1 | /* Copyright (c) 2017 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 | */ | |
| 7 | #include <stddef.h> | |
| 8 | #include <linux/bpf.h> | |
| 9 | #include <linux/if_ether.h> | |
| 10 | #include <linux/if_packet.h> | |
| 11 | #include <linux/ip.h> | |
| 12 | #include <linux/ipv6.h> | |
| 13 | #include <linux/in.h> | |
| 14 | #include <linux/tcp.h> | |
| 15 | #include <linux/pkt_cls.h> | |
| 16 | #include "bpf_helpers.h" | |
| bc1bafbb | 17 | #include "bpf_endian.h" |
| 6882804c | 18 | |
| 6882804c AS |
19 | #define barrier() __asm__ __volatile__("": : :"memory") |
| 20 | int _version SEC("version") = 1; | |
| 21 | ||
| 22 | SEC("test1") | |
| 23 | int process(struct __sk_buff *skb) | |
| 24 | { | |
| 25 | void *data_end = (void *)(long)skb->data_end; | |
| 26 | void *data = (void *)(long)skb->data; | |
| 27 | struct ethhdr *eth = (struct ethhdr *)(data); | |
| 28 | struct tcphdr *tcp = NULL; | |
| 29 | __u8 proto = 255; | |
| 30 | __u64 ihl_len; | |
| 31 | ||
| 32 | if (eth + 1 > data_end) | |
| 33 | return TC_ACT_SHOT; | |
| 34 | ||
| 43bcf707 | 35 | if (eth->h_proto == bpf_htons(ETH_P_IP)) { |
| 6882804c AS |
36 | struct iphdr *iph = (struct iphdr *)(eth + 1); |
| 37 | ||
| 38 | if (iph + 1 > data_end) | |
| 39 | return TC_ACT_SHOT; | |
| 40 | ihl_len = iph->ihl * 4; | |
| 41 | proto = iph->protocol; | |
| 42 | tcp = (struct tcphdr *)((void *)(iph) + ihl_len); | |
| 43bcf707 | 43 | } else if (eth->h_proto == bpf_htons(ETH_P_IPV6)) { |
| 6882804c AS |
44 | struct ipv6hdr *ip6h = (struct ipv6hdr *)(eth + 1); |
| 45 | ||
| 46 | if (ip6h + 1 > data_end) | |
| 47 | return TC_ACT_SHOT; | |
| 48 | ihl_len = sizeof(*ip6h); | |
| 49 | proto = ip6h->nexthdr; | |
| 50 | tcp = (struct tcphdr *)((void *)(ip6h) + ihl_len); | |
| 51 | } | |
| 52 | ||
| 53 | if (tcp) { | |
| 54 | if (((void *)(tcp) + 20) > data_end || proto != 6) | |
| 55 | return TC_ACT_SHOT; | |
| 56 | barrier(); /* to force ordering of checks */ | |
| 57 | if (((void *)(tcp) + 18) > data_end) | |
| 58 | return TC_ACT_SHOT; | |
| 59 | if (tcp->urg_ptr == 123) | |
| 60 | return TC_ACT_OK; | |
| 61 | } | |
| 62 | ||
| 63 | return TC_ACT_UNSPEC; | |
| 64 | } |