62 lines
1.1 KiB
C
62 lines
1.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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#include <sys/socket.h>
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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int invocations = 0, in_use = 0;
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struct {
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__uint(type, BPF_MAP_TYPE_SK_STORAGE);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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__type(key, int);
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__type(value, int);
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} sk_map SEC(".maps");
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SEC("cgroup/sock_create")
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int sock(struct bpf_sock *ctx)
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{
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int *sk_storage;
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__u32 key;
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if (ctx->type != SOCK_DGRAM)
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return 1;
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sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0,
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BPF_SK_STORAGE_GET_F_CREATE);
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if (!sk_storage)
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return 0;
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*sk_storage = 0xdeadbeef;
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__sync_fetch_and_add(&invocations, 1);
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if (in_use > 0) {
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/* BPF_CGROUP_INET_SOCK_RELEASE is _not_ called
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* when we return an error from the BPF
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* program!
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*/
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return 0;
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}
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__sync_fetch_and_add(&in_use, 1);
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return 1;
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}
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SEC("cgroup/sock_release")
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int sock_release(struct bpf_sock *ctx)
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{
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int *sk_storage;
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__u32 key;
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if (ctx->type != SOCK_DGRAM)
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return 1;
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sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0, 0);
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if (!sk_storage || *sk_storage != 0xdeadbeef)
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return 0;
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__sync_fetch_and_add(&invocations, 1);
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__sync_fetch_and_add(&in_use, -1);
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return 1;
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}
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