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