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Helper function bpf_sk_storage_get

v5.2

Definition

Copyright (c) 2015 The Libbpf Authors. All rights reserved.

Get a bpf-local-storage from a sk.

Logically, it could be thought of getting the value from a map with sk as the key. From this perspective, the usage is not much different from bpf_map_lookup_elem(map, &sk) except this helper enforces the key must be a full socket and the map must be a BPF_MAP_TYPE_SK_STORAGE also.

Underneath, the value is stored locally at sk instead of the map. The map is used as the bpf-local-storage "type". The bpf-local-storage "type" (i.e. the map) is searched against all bpf-local-storages residing at sk.

sk is a kernel struct sock pointer for LSM program. sk is a struct bpf_sock pointer for other program types.

An optional flags (BPF_SK_STORAGE_GET_F_CREATE) can be used such that a new bpf-local-storage will be created if one does not exist. value can be used together with BPF_SK_STORAGE_GET_F_CREATE to specify the initial value of a bpf-local-storage. If value is NULL, the new bpf-local-storage will be zero initialized.

Returns

A bpf-local-storage pointer is returned on success.

NULL if not found or there was an error in adding a new bpf-local-storage.

static void *(* const bpf_sk_storage_get)(void *map, void *sk, void *value, __u64 flags) = (void *) 107;

Usage

Docs could be improved

This part of the docs is incomplete, contributions are very welcome

Program types

This helper call can be used in the following program types:

Example

Docs could be improved

This part of the docs is incomplete, contributions are very welcome