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/*
* Copyright (C) 2018 The Android Open Source Project
* Android BPF library - public API
*
* 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 <libbpf.h>
#include <linux/bpf.h>
#include <fstream>
namespace android {
namespace bpf {
// Bpf programs may specify per-program & per-map selinux_context and pin_subdir.
//
// The BpfLoader needs to convert these bpf.o specified strings into an enum
// for internal use (to check that valid values were specified for the specific
// location of the bpf.o file).
//
// It also needs to map selinux_context's into pin_subdir's.
// This is because of how selinux_context is actually implemented via pin+rename.
//
// Thus 'domain' enumerates all selinux_context's/pin_subdir's that the BpfLoader
// is aware of. Thus there currently needs to be a 1:1 mapping between the two.
//
enum class domain : int {
unrecognized = -1, // invalid for this version of the bpfloader
unspecified = 0, // means just use the default for that specific pin location
platform, // fs_bpf /sys/fs/bpf
tethering, // (S+) fs_bpf_tethering /sys/fs/bpf/tethering
net_private, // (T+) fs_bpf_net_private /sys/fs/bpf/net_private
net_shared, // (T+) fs_bpf_net_shared /sys/fs/bpf/net_shared
netd_readonly, // (T+) fs_bpf_netd_readonly /sys/fs/bpf/netd_readonly
netd_shared, // (T+) fs_bpf_netd_shared /sys/fs/bpf/netd_shared
vendor, // (T+) fs_bpf_vendor /sys/fs/bpf/vendor
loader, // (U+) fs_bpf_loader /sys/fs/bpf/loader
};
// Note: this does not include domain::unrecognized, but does include domain::unspecified
static constexpr domain AllDomains[] = {
domain::unspecified,
domain::platform,
domain::tethering,
domain::net_private,
domain::net_shared,
domain::netd_readonly,
domain::netd_shared,
domain::vendor,
domain::loader,
};
static constexpr bool unrecognized(domain d) {
return d == domain::unrecognized;
}
// Note: this doesn't handle unrecognized, handle it first.
static constexpr bool specified(domain d) {
return d != domain::unspecified;
}
static constexpr unsigned long long domainToBitmask(domain d) {
return specified(d) ? 1uLL << (static_cast<int>(d) - 1) : 0;
}
static constexpr bool inDomainBitmask(domain d, unsigned long long v) {
return domainToBitmask(d) & v;
}
struct Location {
const char* const dir = "";
const char* const prefix = "";
unsigned long long allowedDomainBitmask = 0;
const bpf_prog_type* allowedProgTypes = nullptr;
size_t allowedProgTypesLength = 0;
};
// BPF loader implementation. Loads an eBPF ELF object
int loadProg(const char* elfPath, bool* isCritical, const Location &location = {});
// Exposed for testing
unsigned int readSectionUint(const char* name, std::ifstream& elfFile, unsigned int defVal);
// Returns the build type string (from ro.build.type).
const std::string& getBuildType();
// The following functions classify the 3 Android build types.
inline bool isEng() {
return getBuildType() == "eng";
}
inline bool isUser() {
return getBuildType() == "user";
}
inline bool isUserdebug() {
return getBuildType() == "userdebug";
}
} // namespace bpf
} // namespace android
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