Make ADBD announce its presence over mDNS
We now request mdnsd from adb and register a service of type _adb._tcp
for clients to connect to.
Test: Verified service appears in avahi-browse
Bug: 28074466
(cherry picked from 379ac414e4d9f53388d903913022a55695292775)
Change-Id: Ie871b9c8b40e86063cc1e68e8f3e4290ead2d279
diff --git a/adb/daemon/mdns.cpp b/adb/daemon/mdns.cpp
new file mode 100644
index 0000000..85c5a07
--- /dev/null
+++ b/adb/daemon/mdns.cpp
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#include "sysdeps.h"
+
+#include <chrono>
+#include <dns_sd.h>
+#include <endian.h>
+#include <mutex>
+#include <unistd.h>
+
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+
+using namespace std::chrono_literals;
+
+static std::mutex& mdns_lock = *new std::mutex();
+static int port;
+static DNSServiceRef mdns_ref;
+static bool mdns_registered = false;
+
+static void start_mdns() {
+ if (android::base::GetProperty("init.svc.mdnsd", "") == "running") {
+ return;
+ }
+
+ android::base::SetProperty("ctl.start", "mdnsd");
+
+ if (! android::base::WaitForProperty("init.svc.mdnsd", "running", 5s)) {
+ LOG(ERROR) << "Could not start mdnsd.";
+ }
+}
+
+static void mdns_callback(DNSServiceRef /*ref*/,
+ DNSServiceFlags /*flags*/,
+ DNSServiceErrorType errorCode,
+ const char* /*name*/,
+ const char* /*regtype*/,
+ const char* /*domain*/,
+ void* /*context*/) {
+ if (errorCode != kDNSServiceErr_NoError) {
+ LOG(ERROR) << "Encountered mDNS registration error ("
+ << errorCode << ").";
+ }
+}
+
+static void setup_mdns_thread(void* /* unused */) {
+ start_mdns();
+ std::lock_guard<std::mutex> lock(mdns_lock);
+
+ auto error = DNSServiceRegister(&mdns_ref, 0, 0, nullptr, "_adb._tcp",
+ nullptr, nullptr, htobe16((uint16_t)port),
+ 0, nullptr, mdns_callback, nullptr);
+
+ if (error != kDNSServiceErr_NoError) {
+ LOG(ERROR) << "Could not register mDNS service (" << error << ").";
+ mdns_registered = false;
+ }
+
+ mdns_registered = true;
+}
+
+static void teardown_mdns() {
+ std::lock_guard<std::mutex> lock(mdns_lock);
+
+ if (mdns_registered) {
+ DNSServiceRefDeallocate(mdns_ref);
+ }
+}
+
+void setup_mdns(int port_in) {
+ port = port_in;
+ adb_thread_create(setup_mdns_thread, nullptr, nullptr);
+
+ // TODO: Make this more robust against a hard kill.
+ atexit(teardown_mdns);
+}