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