LXR linux/tools/testing/selftests/bpf/progs/twfw.c

   1// SPDX-License-Identifier: GPL-2.0
   2/* Copyright (c) 2021 Facebook */
   3#include <linux/types.h>
   4#include <bpf/bpf_helpers.h>
   5#include <linux/bpf.h>
   6#include <stdint.h>
   7
   8#define TWFW_MAX_TIERS (64)
   9/*
  10 * load is successful
  11 * #define TWFW_MAX_TIERS (64u)$
  12 */
  13
  14struct twfw_tier_value {
  15        unsigned long mask[1];
  16};
  17
  18struct rule {
  19        uint8_t seqnum;
  20};
  21
  22struct rules_map {
  23        __uint(type, BPF_MAP_TYPE_ARRAY);
  24        __type(key, __u32);
  25        __type(value, struct rule);
  26        __uint(max_entries, 1);
  27};
  28
  29struct tiers_map {
  30        __uint(type, BPF_MAP_TYPE_ARRAY);
  31        __type(key, __u32);
  32        __type(value, struct twfw_tier_value);
  33        __uint(max_entries, 1);
  34};
  35
  36struct rules_map rules SEC(".maps");
  37struct tiers_map tiers SEC(".maps");
  38
  39SEC("cgroup_skb/ingress")
  40int twfw_verifier(struct __sk_buff* skb)
  41{
  42        const uint32_t key = 0;
  43        const struct twfw_tier_value* tier = bpf_map_lookup_elem(&tiers, &key);
  44        if (!tier)
  45                return 1;
  46
  47        struct rule* rule = bpf_map_lookup_elem(&rules, &key);
  48        if (!rule)
  49                return 1;
  50
  51        if (rule && rule->seqnum < TWFW_MAX_TIERS) {
  52                /* rule->seqnum / 64 should always be 0 */
  53                unsigned long mask = tier->mask[rule->seqnum / 64];
  54                if (mask)
  55                        return 0;
  56        }
  57        return 1;
  58}
  59