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bpf: INET_DIAG support in bpf_sk_storage

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This patch adds INET_DIAG support to bpf_sk_storage.

1. Although this series adds bpf_sk_storage diag capability to inet sk,
   bpf_sk_storage is in general applicable to all fullsock.  Hence, the
   bpf_sk_storage logic will operate on SK_DIAG_* nlattr.  The caller
   will pass in its specific nesting nlattr (e.g. INET_DIAG_*) as
   the argument.

2. The request will be like:
	INET_DIAG_REQ_SK_BPF_STORAGES (nla_nest) (defined in latter patch)
		SK_DIAG_BPF_STORAGE_REQ_MAP_FD (nla_put_u32)
		SK_DIAG_BPF_STORAGE_REQ_MAP_FD (nla_put_u32)
		......

   Considering there could have multiple bpf_sk_storages in a sk,
   instead of reusing INET_DIAG_INFO ("ss -i"),  the user can select
   some specific bpf_sk_storage to dump by specifying an array of
   SK_DIAG_BPF_STORAGE_REQ_MAP_FD.

   If no SK_DIAG_BPF_STORAGE_REQ_MAP_FD is specified (i.e. an empty
   INET_DIAG_REQ_SK_BPF_STORAGES), it will dump all bpf_sk_storages
   of a sk.

3. The reply will be like:
	INET_DIAG_BPF_SK_STORAGES (nla_nest) (defined in latter patch)
		SK_DIAG_BPF_STORAGE (nla_nest)
			SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
			SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
		SK_DIAG_BPF_STORAGE (nla_nest)
			SK_DIAG_BPF_STORAGE_MAP_ID (nla_put_u32)
			SK_DIAG_BPF_STORAGE_MAP_VALUE (nla_reserve_64bit)
		......

4. Unlike other INET_DIAG info of a sk which is pretty static, the size
   required to dump the bpf_sk_storage(s) of a sk is dynamic as the
   system adding more bpf_sk_storage_map.  It is hard to set a static
   min_dump_alloc size.

   Hence, this series learns it at the runtime and adjust the
   cb->min_dump_alloc as it iterates all sk(s) of a system.  The
   "unsigned int *res_diag_size" in bpf_sk_storage_diag_put()
   is for this purpose.

   The next patch will update the cb->min_dump_alloc as it
   iterates the sk(s).

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200225230421.1975729-1-kafai@fb.com
This commit is contained in:
Martin KaFai Lau
2020-02-25 15:04:21 -08:00
committed by Alexei Starovoitov
parent 0df6d32842
commit 1ed4d92458
5 changed files with 346 additions and 6 deletions
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26
include/uapi/linux/sock_diag.h
View File

@@ -36,4 +36,30 @@ enum sknetlink_groups {
};
#define SKNLGRP_MAX (__SKNLGRP_MAX - 1)
enum {
SK_DIAG_BPF_STORAGE_REQ_NONE,
SK_DIAG_BPF_STORAGE_REQ_MAP_FD,
__SK_DIAG_BPF_STORAGE_REQ_MAX,
};
#define SK_DIAG_BPF_STORAGE_REQ_MAX (__SK_DIAG_BPF_STORAGE_REQ_MAX - 1)
enum {
SK_DIAG_BPF_STORAGE_REP_NONE,
SK_DIAG_BPF_STORAGE,
__SK_DIAG_BPF_STORAGE_REP_MAX,
};
#define SK_DIAB_BPF_STORAGE_REP_MAX (__SK_DIAG_BPF_STORAGE_REP_MAX - 1)
enum {
SK_DIAG_BPF_STORAGE_NONE,
SK_DIAG_BPF_STORAGE_PAD,
SK_DIAG_BPF_STORAGE_MAP_ID,
SK_DIAG_BPF_STORAGE_MAP_VALUE,
__SK_DIAG_BPF_STORAGE_MAX,
};
#define SK_DIAG_BPF_STORAGE_MAX (__SK_DIAG_BPF_STORAGE_MAX - 1)
#endif /* _UAPI__SOCK_DIAG_H__ */