DnsResolver/include/DnsHelperPublic.h

/*
 * Copyright (C) 2023 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <sys/cdefs.h>
#include <sys/types.h>

__BEGIN_DECLS

/*
 * Perform any required initialization - including opening any required BPF maps. This function
 * needs to be called before using other functions of this library.
 *
 * Returns 0 on success, -EOPNOTSUPP when the function is called on the Android version before
 * T. Returns a negative POSIX error code (see errno.h) on other failures.
 */
int ADnsHelper_init();

/*
 * The function reads bpf maps and returns whether the given uid has blocked networking or not. The
 * function is supported starting from Android T.
 *
 * |uid| is a Linux/Android UID to be queried. It is a combination of UserID and AppID.
 * |metered| indicates whether the uid is currently using a billing network.
 *
 * Returns 0(false)/1(true) on success, -EUNATCH when the ADnsHelper_init is not called before
 * calling this function. Returns a negative POSIX error code (see errno.h) on other failures
 * that return from bpf syscall.
 */
int ADnsHelper_isUidNetworkingBlocked(uid_t uid, bool metered);

__END_DECLS