Revert "Delete mdns from netd"

This reverts commit 351a46234247778a3ba31b7fd3a242cc501efbc3.

Reason for revert: main is still used for U QPR, but this should be only removed in V

Bug: 322305340
Bug: 322519244
Bug: 322519244
Change-Id: I0f1bd54e97b43a7eb7c366ae494cb4207d713888

5 files changed, 183 insertions, 0 deletions

diff --git a/server/Android.bp b/server/Android.bp
index 882f0f0c..2aee802f 100644
--- a/server/Android.bp
+++ b/server/Android.bp
@@ -114,6 +114,7 @@ cc_defaults {
         "libselinux",
         "libsysutils",
         "libutils",
+        "mdns_aidl_interface-V1-cpp",
         "netd_event_listener_interface-V1-cpp",
         "oemnetd_aidl_interface-cpp",
     ],
@@ -127,6 +128,7 @@ cc_defaults {
         "EventReporter.cpp",
         "FwmarkServer.cpp",
         "LocalNetwork.cpp",
+        "MDnsService.cpp",
         "NetdCommand.cpp",
         "NetdHwAidlService.cpp",
         "NetdHwService.cpp",
diff --git a/server/MDnsService.cpp b/server/MDnsService.cpp
new file mode 100644
index 00000000..bb70550a
--- /dev/null
+++ b/server/MDnsService.cpp
@@ -0,0 +1,128 @@
+/**
+ * Copyright (c) 2022, 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.
+ */
+
+#define LOG_TAG "MDnsService"
+
+#include "MDnsService.h"
+
+#include <android-base/properties.h>
+#include <binder/Status.h>
+#include <binder_utils/BinderUtil.h>
+
+using android::net::mdns::aidl::DiscoveryInfo;
+using android::net::mdns::aidl::GetAddressInfo;
+using android::net::mdns::aidl::IMDnsEventListener;
+using android::net::mdns::aidl::RegistrationInfo;
+using android::net::mdns::aidl::ResolutionInfo;
+
+using std::literals::chrono_literals::operator""s;
+
+namespace android::net {
+
+#define MDNS_SERVICE_NAME "mdnsd"
+#define MDNS_SERVICE_STATUS "init.svc.mdnsd"
+
+// TODO: DnsResolver has same macro definition but returns ScopedAStatus. Move these macros to
+// BinderUtil.h to do the same permission check.
+#define ENFORCE_ANY_PERMISSION(...)                                \
+    do {                                                           \
+        binder::Status status = checkAnyPermission({__VA_ARGS__}); \
+        if (!status.isOk()) {                                      \
+            return status;                                         \
+        }                                                          \
+    } while (0)
+
+#define ENFORCE_NETWORK_STACK_PERMISSIONS() \
+    ENFORCE_ANY_PERMISSION(PERM_NETWORK_STACK, PERM_MAINLINE_NETWORK_STACK)
+
+status_t MDnsService::start() {
+    IPCThreadState::self()->disableBackgroundScheduling(true);
+    const status_t ret = BinderService<MDnsService>::publish();
+    if (ret != android::OK) {
+        return ret;
+    }
+    return android::OK;
+}
+
+binder::Status MDnsService::startDaemon() {
+    ENFORCE_NETWORK_STACK_PERMISSIONS();
+    if (android::base::GetProperty(MDNS_SERVICE_STATUS, "") == "running") {
+        return android::binder::Status::fromServiceSpecificError(EBUSY, strerror(EBUSY));
+    }
+
+    ALOGD("Starting MDNSD");
+    android::base::SetProperty("ctl.start", MDNS_SERVICE_NAME);
+    // To maintain the same behavior as before, the returned value is not checked.
+    android::base::WaitForProperty(MDNS_SERVICE_STATUS, "running", 5s);
+    return binder::Status::ok();
+}
+
+binder::Status MDnsService::stopDaemon() {
+    ENFORCE_NETWORK_STACK_PERMISSIONS();
+    ALOGD("Stopping MDNSD");
+    android::base::SetProperty("ctl.stop", MDNS_SERVICE_NAME);
+    android::base::WaitForProperty(MDNS_SERVICE_STATUS, "stopped", 5s);
+    return binder::Status::ok();
+}
+
+binder::Status MDnsService::registerService(const RegistrationInfo&) {
+    // TODO(b/298594687): switch from EX_SERVICE_SPECIFIC to DEPRECATED when tethering module
+    // for 2024-02 release is fully rolled out and prebuilt updated in AP1A.xxxxxx.yy build.
+    // Return EX_SERVICE_SPECIFIC for short-term only because callers in tethering module do not
+    // catch the EX_UNSUPPORTED_OPERATION. It will throw an exception and cause a fatal exception.
+    // The EX_UNSUPPORTED_OPERATION has been catched in tethering module since 2024-02 release.
+    // TODO(b/298594687): switch to DEPRECATED.
+    return binder::Status::fromExceptionCode(binder::Status::EX_SERVICE_SPECIFIC);
+    // DEPRECATED;
+}
+
+binder::Status MDnsService::discover(const DiscoveryInfo&) {
+    // TODO(b/298594687): switch to DEPRECATED.
+    return binder::Status::fromExceptionCode(binder::Status::EX_SERVICE_SPECIFIC);
+    // DEPRECATED;
+}
+
+binder::Status MDnsService::resolve(const ResolutionInfo&) {
+    // TODO(b/298594687): switch to DEPRECATED.
+    return binder::Status::fromExceptionCode(binder::Status::EX_SERVICE_SPECIFIC);
+    // DEPRECATED;
+}
+
+binder::Status MDnsService::getServiceAddress(const GetAddressInfo&) {
+    // TODO(b/298594687): switch to DEPRECATED.
+    return binder::Status::fromExceptionCode(binder::Status::EX_SERVICE_SPECIFIC);
+    // DEPRECATED;
+}
+
+binder::Status MDnsService::stopOperation(int32_t) {
+    // TODO(b/298594687): switch to DEPRECATED.
+    return binder::Status::fromExceptionCode(binder::Status::EX_SERVICE_SPECIFIC);
+    // DEPRECATED;
+}
+
+binder::Status MDnsService::registerEventListener(const android::sp<IMDnsEventListener>&) {
+    // TODO(b/298594687): switch to DEPRECATED.
+    return binder::Status::fromExceptionCode(binder::Status::EX_SERVICE_SPECIFIC);
+    // DEPRECATED;
+}
+
+binder::Status MDnsService::unregisterEventListener(const android::sp<IMDnsEventListener>&) {
+    // TODO(b/298594687): switch to DEPRECATED.
+    return binder::Status::fromExceptionCode(binder::Status::EX_SERVICE_SPECIFIC);
+    // DEPRECATED;
+}
+
+}  // namespace android::net
diff --git a/server/MDnsService.h b/server/MDnsService.h
new file mode 100644
index 00000000..b8ead656
--- /dev/null
+++ b/server/MDnsService.h
@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) 2022, 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 <android/net/mdns/aidl/BnMDns.h>
+#include <binder/BinderService.h>
+
+namespace android::net {
+
+class MDnsService : public BinderService<MDnsService>, public android::net::mdns::aidl::BnMDns {
+  public:
+    static status_t start();
+    static char const* getServiceName() { return "mdns"; }
+
+    binder::Status startDaemon() override;
+    binder::Status stopDaemon() override;
+    binder::Status registerService(
+            const ::android::net::mdns::aidl::RegistrationInfo& info) override;
+    binder::Status discover(const ::android::net::mdns::aidl::DiscoveryInfo& info) override;
+    binder::Status resolve(const ::android::net::mdns::aidl::ResolutionInfo& info) override;
+    binder::Status getServiceAddress(
+            const ::android::net::mdns::aidl::GetAddressInfo& info) override;
+    binder::Status stopOperation(int32_t id) override;
+    binder::Status registerEventListener(
+            const android::sp<android::net::mdns::aidl::IMDnsEventListener>& listener) override;
+    binder::Status unregisterEventListener(
+            const android::sp<android::net::mdns::aidl::IMDnsEventListener>& listener) override;
+};
+
+}  // namespace android::net
diff --git a/server/main.cpp b/server/main.cpp
index a3a111bc..b0c5406d 100644
--- a/server/main.cpp
+++ b/server/main.cpp
@@ -42,6 +42,7 @@
 
 #include "Controllers.h"
 #include "FwmarkServer.h"
+#include "MDnsService.h"
 #include "NFLogListener.h"
 #include "NetdConstants.h"
 #include "NetdHwAidlService.h"
@@ -61,6 +62,7 @@ using android::net::FwmarkServer;
 using android::net::gCtls;
 using android::net::gLog;
 using android::net::makeNFLogListener;
+using android::net::MDnsService;
 using android::net::NetdHwService;
 using android::net::NetdNativeService;
 using android::net::NetlinkManager;
@@ -202,6 +204,12 @@ int main() {
     }
     gLog.info("Registering NetdNativeService: %" PRId64 "us", subTime.getTimeAndResetUs());
 
+    if ((ret = MDnsService::start()) != android::OK) {
+        ALOGE("Unable to start MDnsService: %d", ret);
+        exit(1);
+    }
+    gLog.info("Registering MDnsService: %" PRId64 "us", subTime.getTimeAndResetUs());
+
     android::net::process::ScopedPidFile pidFile(PID_FILE_PATH);
 
     // Now that netd is ready to process commands, advertise service availability for HAL clients.
diff --git a/server/netd.rc b/server/netd.rc
index 79dbea41..d8250c2d 100644
--- a/server/netd.rc
+++ b/server/netd.rc
@@ -4,6 +4,7 @@ service netd /system/bin/netd
     user root
     group root net_admin
     socket dnsproxyd stream 0660 root inet
+    socket mdns stream 0660 root system
     socket fwmarkd stream 0660 root inet
     onrestart restart zygote
     onrestart restart zygote_secondary