LXR linux/samples/bpf/test_cgrp2_tc

   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 */
   7#define KBUILD_MODNAME "foo"
   8#include <uapi/linux/if_ether.h>
   9#include <uapi/linux/in6.h>
  10#include <uapi/linux/ipv6.h>
  11#include <uapi/linux/pkt_cls.h>
  12#include <uapi/linux/bpf.h>
  13#include <bpf/bpf_helpers.h>
  14
  15/* copy of 'struct ethhdr' without __packed */
  16struct eth_hdr {
  17        unsigned char   h_dest[ETH_ALEN];
  18        unsigned char   h_source[ETH_ALEN];
  19        unsigned short  h_proto;
  20};
  21
  22#define PIN_GLOBAL_NS           2
  23struct bpf_elf_map {
  24        __u32 type;
  25        __u32 size_key;
  26        __u32 size_value;
  27        __u32 max_elem;
  28        __u32 flags;
  29        __u32 id;
  30        __u32 pinning;
  31};
  32
  33struct bpf_elf_map SEC("maps") test_cgrp2_array_pin = {
  34        .type           = BPF_MAP_TYPE_CGROUP_ARRAY,
  35        .size_key       = sizeof(uint32_t),
  36        .size_value     = sizeof(uint32_t),
  37        .pinning        = PIN_GLOBAL_NS,
  38        .max_elem       = 1,
  39};
  40
  41SEC("filter")
  42int handle_egress(struct __sk_buff *skb)
  43{
  44        void *data = (void *)(long)skb->data;
  45        struct eth_hdr *eth = data;
  46        struct ipv6hdr *ip6h = data + sizeof(*eth);
  47        void *data_end = (void *)(long)skb->data_end;
  48        char dont_care_msg[] = "dont care %04x %d\n";
  49        char pass_msg[] = "pass\n";
  50        char reject_msg[] = "reject\n";
  51
  52        /* single length check */
  53        if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
  54                return TC_ACT_OK;
  55
  56        if (eth->h_proto != htons(ETH_P_IPV6) ||
  57            ip6h->nexthdr != IPPROTO_ICMPV6) {
  58                bpf_trace_printk(dont_care_msg, sizeof(dont_care_msg),
  59                                 eth->h_proto, ip6h->nexthdr);
  60                return TC_ACT_OK;
  61        } else if (bpf_skb_under_cgroup(skb, &test_cgrp2_array_pin, 0) != 1) {
  62                bpf_trace_printk(pass_msg, sizeof(pass_msg));
  63                return TC_ACT_OK;
  64        } else {
  65                bpf_trace_printk(reject_msg, sizeof(reject_msg));
  66                return TC_ACT_SHOT;
  67        }
  68}
  69
  70char _license[] SEC("license") = "GPL";
  71