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