97 lines
2.3 KiB
C
97 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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char _license[] SEC("license") = "GPL";
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#define SOL_CUSTOM 0xdeadbeef
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#define CUSTOM_INHERIT1 0
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#define CUSTOM_INHERIT2 1
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#define CUSTOM_LISTENER 2
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struct sockopt_inherit {
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__u8 val;
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};
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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 | BPF_F_CLONE);
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__type(key, int);
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__type(value, struct sockopt_inherit);
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} cloned1_map SEC(".maps");
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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 | BPF_F_CLONE);
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__type(key, int);
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__type(value, struct sockopt_inherit);
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} cloned2_map SEC(".maps");
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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, struct sockopt_inherit);
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} listener_only_map SEC(".maps");
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static __inline struct sockopt_inherit *get_storage(struct bpf_sockopt *ctx)
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{
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if (ctx->optname == CUSTOM_INHERIT1)
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return bpf_sk_storage_get(&cloned1_map, ctx->sk, 0,
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BPF_SK_STORAGE_GET_F_CREATE);
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else if (ctx->optname == CUSTOM_INHERIT2)
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return bpf_sk_storage_get(&cloned2_map, ctx->sk, 0,
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BPF_SK_STORAGE_GET_F_CREATE);
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else
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return bpf_sk_storage_get(&listener_only_map, ctx->sk, 0,
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BPF_SK_STORAGE_GET_F_CREATE);
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}
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SEC("cgroup/getsockopt")
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int _getsockopt(struct bpf_sockopt *ctx)
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{
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__u8 *optval_end = ctx->optval_end;
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struct sockopt_inherit *storage;
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__u8 *optval = ctx->optval;
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if (ctx->level != SOL_CUSTOM)
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return 1; /* only interested in SOL_CUSTOM */
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if (optval + 1 > optval_end)
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return 0; /* EPERM, bounds check */
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storage = get_storage(ctx);
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if (!storage)
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return 0; /* EPERM, couldn't get sk storage */
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ctx->retval = 0; /* Reset system call return value to zero */
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optval[0] = storage->val;
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ctx->optlen = 1;
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return 1;
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}
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SEC("cgroup/setsockopt")
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int _setsockopt(struct bpf_sockopt *ctx)
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{
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__u8 *optval_end = ctx->optval_end;
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struct sockopt_inherit *storage;
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__u8 *optval = ctx->optval;
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if (ctx->level != SOL_CUSTOM)
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return 1; /* only interested in SOL_CUSTOM */
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if (optval + 1 > optval_end)
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return 0; /* EPERM, bounds check */
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storage = get_storage(ctx);
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if (!storage)
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return 0; /* EPERM, couldn't get sk storage */
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storage->val = optval[0];
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ctx->optlen = -1;
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return 1;
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}
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