import bpfloader into p/m/C

These are unmodified files, without history.
Getting these to do something useful will come later.

Generated via:
  cp //system/bpf/bpfloader/bpfloader.rc netbpfload.rc
  cp //system/bpf/bpfloader/BpfLoader.cpp NetBpfLoad.cpp
  cp //system/bpf/libbpf_android/include/libbpf_android.h loader.h
  cp //system/bpf/libbpf_android/Loader.cpp loader.cpp

Change-Id: I1677b899a51e1289a7a9806d6f5c34450b9e7c47
diff --git a/netbpfload/loader.h b/netbpfload/loader.h
new file mode 100644
index 0000000..cc8a942
--- /dev/null
+++ b/netbpfload/loader.h
@@ -0,0 +1,111 @@
+/*
+ * 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 <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