1 files changed, 95 insertions, 0 deletions
diff --git a/api/logic/launch/steps/LookupServerAddress.cpp b/api/logic/launch/steps/LookupServerAddress.cpp
new file mode 100644
index 00000000..de56c28a
--- /dev/null
+++ b/api/logic/launch/steps/LookupServerAddress.cpp
@@ -0,0 +1,95 @@
+/* Copyright 2013-2021 MultiMC Contributors
+ *
+ * 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 "LookupServerAddress.h"
+
+#include <launch/LaunchTask.h>
+
+LookupServerAddress::LookupServerAddress(LaunchTask *parent) :
+    LaunchStep(parent), m_dnsLookup(new QDnsLookup(this))
+{
+    connect(m_dnsLookup, &QDnsLookup::finished, this, &LookupServerAddress::on_dnsLookupFinished);
+
+    m_dnsLookup->setType(QDnsLookup::SRV);
+}
+
+void LookupServerAddress::setLookupAddress(const QString &lookupAddress)
+{
+    m_lookupAddress = lookupAddress;
+    m_dnsLookup->setName(QString("_minecraft._tcp.%1").arg(lookupAddress));
+}
+
+void LookupServerAddress::setOutputAddressPtr(MinecraftServerTargetPtr output)
+{
+    m_output = std::move(output);
+}
+
+bool LookupServerAddress::abort()
+{
+    m_dnsLookup->abort();
+    emitFailed("Aborted");
+    return true;
+}
+
+void LookupServerAddress::executeTask()
+{
+    m_dnsLookup->lookup();
+}
+
+void LookupServerAddress::on_dnsLookupFinished()
+{
+    if (isFinished())
+    {
+        // Aborted
+        return;
+    }
+
+    if (m_dnsLookup->error() != QDnsLookup::NoError)
+    {
+        emit logLine(QString("Failed to resolve server address (this is NOT an error!) %1: %2\n")
+            .arg(m_dnsLookup->name(), m_dnsLookup->errorString()), MessageLevel::MultiMC);
+        resolve(m_lookupAddress, 25565); // Technically the task failed, however, we don't abort the launch
+                                                      // and leave it up to minecraft to fail (or maybe not) when connecting
+        return;
+    }
+
+    const auto records = m_dnsLookup->serviceRecords();
+    if (records.empty())
+    {
+        emit logLine(
+                QString("Failed to resolve server address %1: the DNS lookup succeeded, but no records were returned.\n")
+                .arg(m_dnsLookup->name()), MessageLevel::Warning);
+        resolve(m_lookupAddress, 25565); // Technically the task failed, however, we don't abort the launch
+                                                      // and leave it up to minecraft to fail (or maybe not) when connecting
+        return;
+    }
+
+    const auto &firstRecord = records.at(0);
+    quint16 port = firstRecord.port();
+
+    emit logLine(QString("Resolved server address %1 to %2 with port %3\n").arg(
+            m_dnsLookup->name(), firstRecord.target(), QString::number(port)),MessageLevel::MultiMC);
+    resolve(firstRecord.target(), port);
+}
+
+void LookupServerAddress::resolve(const QString &address, quint16 port)
+{
+    m_output->address = address;
+    m_output->port = port;
+
+    emitSucceeded();
+    m_dnsLookup->deleteLater();
+}