Fix DNS lookup problems #161

shadowsocks · Feb 3, 2018 · 49af99a · 49af99a
1 parent fd724ad
commit 49af99a
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Showing 3 changed files with 68 additions and 17 deletions.
diff --git a/lib/types/address.cpp b/lib/types/address.cpp
@@ -25,11 +25,28 @@
 #include "address.h"
 #include "util/common.h"
 
-#include <QDnsLookup>
-#include <memory>
-
 namespace  QSS {
 
+void DnsLookup::lookup(const QString& hostname)
+{
+    QHostInfo::lookupHost(hostname, this, SLOT(lookedUp(QHostInfo)));
+}
+
+const QList<QHostAddress> DnsLookup::iplist() const
+{
+    return m_ips;
+}
+
+void DnsLookup::lookedUp(const QHostInfo &info)
+{
+    if (info.error() != QHostInfo::NoError) {
+        qWarning("DNS lookup failed: %s", info.errorString().toStdString().data());
+    } else {
+        m_ips = info.addresses();
+    }
+    emit finished();
+}
+
 Address::Address(const std::string &a, uint16_t p)
 {
     data.second = p;
@@ -75,19 +92,19 @@ void Address::lookUp(Address::LookUpCallback cb)
     if (isIPValid()) {
         return cb(true);
     }
-    std::shared_ptr<QDnsLookup> dns(new QDnsLookup(QDnsLookup::Type::ANY, QString::fromStdString(data.first)));
-    QObject::connect(dns.get(), &QDnsLookup::finished,
-                     [cb, dns, this]() {
-        if (dns->error() != QDnsLookup::NoError) {
-            qDebug("Failed to look up host address: %s", dns->errorString().toStdString().data());
-            cb(false);
-        } else {
-            ipAddrList.clear();
-            for (const QDnsHostAddressRecord& record : dns->hostAddressRecords()) {
-                ipAddrList.push_back(record.value());
-            }
-            cb(true);
-        }});
+
+    if (dns) {
+        // DNS lookup is in-progress
+        return;
+    }
+
+    dns = std::make_shared<DnsLookup>();
+    QObject::connect(dns.get(), &DnsLookup::finished, [cb, this]() {
+        ipAddrList = dns->iplist().toVector().toStdVector();
+        cb(!ipAddrList.empty());
+        dns.reset();
+    });
+    dns->lookup(QString::fromStdString(data.first));
 }
 
 bool Address::blockingLookUp()

diff --git a/lib/types/address.h b/lib/types/address.h
@@ -28,12 +28,32 @@
 #include <QString>
 #include <QHostAddress>
 #include <QHostInfo>
-#include <vector>
+
 #include <functional>
+#include <memory>
+#include <vector>
 #include "util/export.h"
 
 namespace QSS {
 
+class QSS_EXPORT DnsLookup : public QObject
+{
+    // A simple wrapper class to provide asynchronous DNS lookup
+    Q_OBJECT
+public:
+    void lookup(const QString& hostname);
+    const QList<QHostAddress> iplist() const;
+
+signals:
+    void finished();
+
+private slots:
+    void lookedUp(const QHostInfo& info);
+
+private:
+    QList<QHostAddress> m_ips;
+};
+
 class QSS_EXPORT Address
 {
 public:
@@ -118,6 +138,7 @@ class QSS_EXPORT Address
 private:
     std::pair<std::string, uint16_t> data;//first: address string; second: port
     std::vector<QHostAddress> ipAddrList;
+    std::shared_ptr<DnsLookup> dns;
 };
 
 }

diff --git a/test/address.cpp b/test/address.cpp
@@ -17,6 +17,7 @@ private Q_SLOTS:
     void testSetAddress();
     void testSetIPAddress();
     void testSetPort();
+    void testLookup();
 };
 
 void Address::testConstructor1()
@@ -80,5 +81,17 @@ void Address::testSetPort()
     QCOMPARE(a.getPort(), port);
 }
 
+void Address::testLookup()
+{
+    QSS::Address a("www.google.com", 443);
+    a.lookUp([&a](bool success) {
+        if (success) {
+            QVERIFY(a.isIPValid());
+        } else {
+            QVERIFY(!a.isIPValid());
+        }
+    });
+}
+
 QTEST_MAIN(Address)
 #include "address.moc"