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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */
#include <linux/types.h>
#include <bpf/bpf_helpers.h>
#include <linux/bpf.h>
#include <stdint.h>
#define TWFW_MAX_TIERS (64)
/*
* load is successful
* #define TWFW_MAX_TIERS (64u)$
*/
struct twfw_tier_value {
unsigned long mask[1];
};
struct rule {
uint8_t seqnum;
};
struct rules_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, __u32);
__type(value, struct rule);
__uint(max_entries, 1);
};
struct tiers_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, __u32);
__type(value, struct twfw_tier_value);
__uint(max_entries, 1);
};
struct rules_map rules SEC(".maps");
struct tiers_map tiers SEC(".maps");
SEC("cgroup_skb/ingress")
int twfw_verifier(struct __sk_buff* skb)
{
const uint32_t key = 0;
const struct twfw_tier_value* tier = bpf_map_lookup_elem(&tiers, &key);
if (!tier)
return 1;
struct rule* rule = bpf_map_lookup_elem(&rules, &key);
if (!rule)
return 1;
if (rule && rule->seqnum < TWFW_MAX_TIERS) {
/* rule->seqnum / 64 should always be 0 */
unsigned long mask = tier->mask[rule->seqnum / 64];
if (mask)
return 0;
}
return 1;
}
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