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 14 struct twfw_tier_value { 15 unsigned long mask[1]; 16 }; 17 18 struct rule { 19 uint8_t seqnum; 20 }; 21 22 struct 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 29 struct 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 36 struct rules_map rules SEC(".maps"); 37 struct tiers_map tiers SEC(".maps"); 38 39 SEC("cgroup_skb/ingress") 40 int 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