1c3bbf176SStanislav Fomichev // SPDX-License-Identifier: GPL-2.0
2c3bbf176SStanislav Fomichev #include <linux/bpf.h>
33e689141SToke Høiland-Jørgensen #include <bpf/bpf_helpers.h>
4c3bbf176SStanislav Fomichev
5c3bbf176SStanislav Fomichev char _license[] SEC("license") = "GPL";
6c3bbf176SStanislav Fomichev
7c3bbf176SStanislav Fomichev #define SOL_CUSTOM 0xdeadbeef
8c3bbf176SStanislav Fomichev #define CUSTOM_INHERIT1 0
9c3bbf176SStanislav Fomichev #define CUSTOM_INHERIT2 1
10c3bbf176SStanislav Fomichev #define CUSTOM_LISTENER 2
11c3bbf176SStanislav Fomichev
12*e01b4a72SStanislav Fomichev __u32 page_size = 0;
13*e01b4a72SStanislav Fomichev
14c3bbf176SStanislav Fomichev struct sockopt_inherit {
15c3bbf176SStanislav Fomichev __u8 val;
16c3bbf176SStanislav Fomichev };
17c3bbf176SStanislav Fomichev
18c3bbf176SStanislav Fomichev struct {
19c3bbf176SStanislav Fomichev __uint(type, BPF_MAP_TYPE_SK_STORAGE);
20c3bbf176SStanislav Fomichev __uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE);
21c3bbf176SStanislav Fomichev __type(key, int);
22c3bbf176SStanislav Fomichev __type(value, struct sockopt_inherit);
23c3bbf176SStanislav Fomichev } cloned1_map SEC(".maps");
24c3bbf176SStanislav Fomichev
25c3bbf176SStanislav Fomichev struct {
26c3bbf176SStanislav Fomichev __uint(type, BPF_MAP_TYPE_SK_STORAGE);
27c3bbf176SStanislav Fomichev __uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE);
28c3bbf176SStanislav Fomichev __type(key, int);
29c3bbf176SStanislav Fomichev __type(value, struct sockopt_inherit);
30c3bbf176SStanislav Fomichev } cloned2_map SEC(".maps");
31c3bbf176SStanislav Fomichev
32c3bbf176SStanislav Fomichev struct {
33c3bbf176SStanislav Fomichev __uint(type, BPF_MAP_TYPE_SK_STORAGE);
34c3bbf176SStanislav Fomichev __uint(map_flags, BPF_F_NO_PREALLOC);
35c3bbf176SStanislav Fomichev __type(key, int);
36c3bbf176SStanislav Fomichev __type(value, struct sockopt_inherit);
37c3bbf176SStanislav Fomichev } listener_only_map SEC(".maps");
38c3bbf176SStanislav Fomichev
get_storage(struct bpf_sockopt * ctx)39c3bbf176SStanislav Fomichev static __inline struct sockopt_inherit *get_storage(struct bpf_sockopt *ctx)
40c3bbf176SStanislav Fomichev {
41c3bbf176SStanislav Fomichev if (ctx->optname == CUSTOM_INHERIT1)
42c3bbf176SStanislav Fomichev return bpf_sk_storage_get(&cloned1_map, ctx->sk, 0,
43c3bbf176SStanislav Fomichev BPF_SK_STORAGE_GET_F_CREATE);
44c3bbf176SStanislav Fomichev else if (ctx->optname == CUSTOM_INHERIT2)
45c3bbf176SStanislav Fomichev return bpf_sk_storage_get(&cloned2_map, ctx->sk, 0,
46c3bbf176SStanislav Fomichev BPF_SK_STORAGE_GET_F_CREATE);
47c3bbf176SStanislav Fomichev else
48c3bbf176SStanislav Fomichev return bpf_sk_storage_get(&listener_only_map, ctx->sk, 0,
49c3bbf176SStanislav Fomichev BPF_SK_STORAGE_GET_F_CREATE);
50c3bbf176SStanislav Fomichev }
51c3bbf176SStanislav Fomichev
52c3bbf176SStanislav Fomichev SEC("cgroup/getsockopt")
_getsockopt(struct bpf_sockopt * ctx)53c3bbf176SStanislav Fomichev int _getsockopt(struct bpf_sockopt *ctx)
54c3bbf176SStanislav Fomichev {
55c3bbf176SStanislav Fomichev __u8 *optval_end = ctx->optval_end;
56c3bbf176SStanislav Fomichev struct sockopt_inherit *storage;
57c3bbf176SStanislav Fomichev __u8 *optval = ctx->optval;
58c3bbf176SStanislav Fomichev
59c3bbf176SStanislav Fomichev if (ctx->level != SOL_CUSTOM)
60*e01b4a72SStanislav Fomichev goto out; /* only interested in SOL_CUSTOM */
61c3bbf176SStanislav Fomichev
62c3bbf176SStanislav Fomichev if (optval + 1 > optval_end)
63c3bbf176SStanislav Fomichev return 0; /* EPERM, bounds check */
64c3bbf176SStanislav Fomichev
65c3bbf176SStanislav Fomichev storage = get_storage(ctx);
66c3bbf176SStanislav Fomichev if (!storage)
67c3bbf176SStanislav Fomichev return 0; /* EPERM, couldn't get sk storage */
68c3bbf176SStanislav Fomichev
69c3bbf176SStanislav Fomichev ctx->retval = 0; /* Reset system call return value to zero */
70c3bbf176SStanislav Fomichev
71c3bbf176SStanislav Fomichev optval[0] = storage->val;
72c3bbf176SStanislav Fomichev ctx->optlen = 1;
73c3bbf176SStanislav Fomichev
74c3bbf176SStanislav Fomichev return 1;
75*e01b4a72SStanislav Fomichev
76*e01b4a72SStanislav Fomichev out:
77*e01b4a72SStanislav Fomichev /* optval larger than PAGE_SIZE use kernel's buffer. */
78*e01b4a72SStanislav Fomichev if (ctx->optlen > page_size)
79*e01b4a72SStanislav Fomichev ctx->optlen = 0;
80*e01b4a72SStanislav Fomichev return 1;
81c3bbf176SStanislav Fomichev }
82c3bbf176SStanislav Fomichev
83c3bbf176SStanislav Fomichev SEC("cgroup/setsockopt")
_setsockopt(struct bpf_sockopt * ctx)84c3bbf176SStanislav Fomichev int _setsockopt(struct bpf_sockopt *ctx)
85c3bbf176SStanislav Fomichev {
86c3bbf176SStanislav Fomichev __u8 *optval_end = ctx->optval_end;
87c3bbf176SStanislav Fomichev struct sockopt_inherit *storage;
88c3bbf176SStanislav Fomichev __u8 *optval = ctx->optval;
89c3bbf176SStanislav Fomichev
90c3bbf176SStanislav Fomichev if (ctx->level != SOL_CUSTOM)
91*e01b4a72SStanislav Fomichev goto out; /* only interested in SOL_CUSTOM */
92c3bbf176SStanislav Fomichev
93c3bbf176SStanislav Fomichev if (optval + 1 > optval_end)
94c3bbf176SStanislav Fomichev return 0; /* EPERM, bounds check */
95c3bbf176SStanislav Fomichev
96c3bbf176SStanislav Fomichev storage = get_storage(ctx);
97c3bbf176SStanislav Fomichev if (!storage)
98c3bbf176SStanislav Fomichev return 0; /* EPERM, couldn't get sk storage */
99c3bbf176SStanislav Fomichev
100c3bbf176SStanislav Fomichev storage->val = optval[0];
101c3bbf176SStanislav Fomichev ctx->optlen = -1;
102c3bbf176SStanislav Fomichev
103c3bbf176SStanislav Fomichev return 1;
104*e01b4a72SStanislav Fomichev
105*e01b4a72SStanislav Fomichev out:
106*e01b4a72SStanislav Fomichev /* optval larger than PAGE_SIZE use kernel's buffer. */
107*e01b4a72SStanislav Fomichev if (ctx->optlen > page_size)
108*e01b4a72SStanislav Fomichev ctx->optlen = 0;
109*e01b4a72SStanislav Fomichev return 1;
110c3bbf176SStanislav Fomichev }
111