| 1 | // SPDX-License-Identifier: GPL-2.0 |
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| 2 | // Copyright (c) 2018 Facebook |
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| 3 | |
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| 4 | #include <linux/bpf.h> |
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| 5 | #include <linux/pkt_cls.h> |
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| 6 | |
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| 7 | #include <string.h> |
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| 8 | |
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| 9 | #include <bpf/bpf_helpers.h> |
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| 10 | |
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| 11 | #define NUM_CGROUP_LEVELS 4 |
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| 12 | |
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| 13 | struct { |
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| 14 | __uint(type, BPF_MAP_TYPE_ARRAY); |
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| 15 | __type(key, __u32); |
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| 16 | __type(value, __u64); |
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| 17 | __uint(max_entries, NUM_CGROUP_LEVELS); |
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| 18 | } cgroup_ids SEC(".maps" ); |
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| 19 | |
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| 20 | static __always_inline void log_nth_level(struct __sk_buff *skb, __u32 level) |
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| 21 | { |
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| 22 | __u64 id; |
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| 23 | |
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| 24 | /* [1] &level passed to external function that may change it, it's |
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| 25 | * incompatible with loop unroll. |
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| 26 | */ |
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| 27 | id = bpf_skb_ancestor_cgroup_id(skb, level); |
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| 28 | bpf_map_update_elem(&cgroup_ids, &level, &id, 0); |
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| 29 | } |
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| 30 | |
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| 31 | SEC("cgroup_id_logger" ) |
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| 32 | int log_cgroup_id(struct __sk_buff *skb) |
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| 33 | { |
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| 34 | /* Loop unroll can't be used here due to [1]. Unrolling manually. |
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| 35 | * Number of calls should be in sync with NUM_CGROUP_LEVELS. |
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| 36 | */ |
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| 37 | log_nth_level(skb, level: 0); |
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| 38 | log_nth_level(skb, level: 1); |
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| 39 | log_nth_level(skb, level: 2); |
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| 40 | log_nth_level(skb, level: 3); |
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| 41 | |
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| 42 | return TC_ACT_OK; |
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| 43 | } |
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| 44 | |
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| 45 | char _license[] SEC("license" ) = "GPL" ; |
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| 46 | |
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