resolve domains, display error if in use

.github/workflows/main.yml

@@ -18,6 +18,7 @@ jobs:
     - uses: actions/checkout@main
     - name: Install Qt
       uses: jurplel/install-qt-action@v3
+    - uses: ilammy/msvc-dev-cmd@v1
     - name: Build ${{ matrix.platform }}
       shell: bash
       run: cd CaptiveDNS && qmake && make

CaptiveDNS/CaptiveDNS.pro

@@ -64,6 +64,7 @@ FORMS += \
     cacheviewer.ui
 
 CONFIG += mobility
+
 MOBILITY = 
 
 DISTFILES += \

CaptiveDNS/dnsserverwindow.cpp

@@ -30,12 +30,16 @@ You should have received a copy of the GNU General Public License along
 with this program; if not, write to the Free Software Foundation, Inc.,
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */
 
+Ui::DNSServerWindow* DNSServerWindow::mainUi = NULL;
+
 DNSServerWindow::DNSServerWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::DNSServerWindow)
 {
     ui->setupUi(this);
     qRegisterMetaType<ListEntry>("ListEntry");
     qRegisterMetaType<std::vector<ListEntry>>("std::vector<ListEntry>");
     qRegisterMetaType<QHostAddress>("QHostAddress");
+
+    DNSServerWindow::mainUi = ui;
 
     settingspath = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
     QDir d{settingspath};
@@ -159,6 +163,39 @@ void DNSServerWindow::listeningIPsUpdate()
 
     if(ipslist.size() > 0)
     {
+        // sort the ipslist so that the first one is the one we want to respond with
+        // (eg. prioritize 192.168.x.x over 10.x.x.x, over 172.16.x.x, etc.)
+
+        // sort the list
+        std::sort(ipslist.begin(), ipslist.end());
+
+        // check for 10.x.x.x
+        for (int i = 0; i < ipslist.size(); i++)
+        {
+            if((ipslist[i] & 0xFF000000) == 0x0A000000)
+            {
+                // move it to the front
+                ipslist.prepend(ipslist[i]);
+                ipslist.remove(i+1);
+                break;
+            }
+        }
+
+        // check for 192.168.x.x
+        for (int i = 0; i < ipslist.size(); i++)
+        {
+            if((ipslist[i] & 0xFFFF0000) == 0xC0A80000)
+            {
+                // move it to the front
+                ipslist.prepend(ipslist[i]);
+                ipslist.remove(i+1);
+                break;
+            }
+        }
+
+        // really, which IP to use should be a choice in the UI
+        // but for now we'll just use the first one and sort the list
+
         server->listeningIPs = ipslist;
     }
     if(ipv6slist.size() > 0)
@@ -498,7 +535,6 @@ bool DNSServerWindow::settingsLoad()
 
     // blacklist only (allow all non-captive portal domains)
     server->whitelistmode = false;
-    on_blacklistButton_clicked();
 
     // no settings, so no initial mode
     server->initialMode = false;
@@ -534,35 +570,7 @@ void DNSServerWindow::on_saveButton_clicked()
 
 void DNSServerWindow::on_removeButton_clicked()
 {
-    // auto selected = ui->dnslist->selectedItems();
-    // for(QTreeWidgetItem *i : selected)
-    // {
-    //     if(server->whitelistmode)
-    //     {
-    //         for(int x = 0; x < server->whitelist.size(); x++)
-    //         {
-    //             if(i->text(1) == server->whitelist[x].hostname)
-    //             {
-    //                 qDebug() << "Removing from whitelist:" << i->text(1);
-    //                 server->whitelist.remove(x);
-    //                 break;
-    //             }
-    //         }
-    //     }
-    //     else
-    //     {
-    //         for(int x = 0; x < server->blacklist.size(); x++)
-    //         {
-    //             if(i->text(1) == server->blacklist[x].hostname)
-    //             {
-    //                  qDebug() << "Removing from blacklist:" << i->text(1);
-    //                 server->blacklist.remove(x);
-    //                 break;
-    //             }
-    //         }
-    //     }
-    // }
-    // qDeleteAll(selected);
+    // blanked out
 }
 
 void DNSServerWindow::on_hostnameEdit_returnPressed()
@@ -578,41 +586,7 @@ void DNSServerWindow::on_ipEdit_returnPressed()
 void DNSServerWindow::on_secondAddButton_clicked()
 {
     bool alreadyAdded = false;
-    // auto selected = ui->dnsqueries->selectedItems();
-    // if(server->whitelistmode)
-    // {   
-    //     for(QTreeWidgetItem *i : selected)
-    //     {
-    //         for(ListEntry &e : server->whitelist)
-    //         {
-    //             if(e.hostname == i->text(1))
-    //             {
-    //                 alreadyAdded = true;
-    //                 break;
-    //             }
-    //         }
-
-    //         if(!alreadyAdded)
-    //             server->whitelist.append(ListEntry(i->text(1)));
-    //     }
-    // }
-    // else
-    // {
-    //     for(QTreeWidgetItem *i : selected)
-    //     {
-    //         for(ListEntry &e : server->blacklist)
-    //         {
-    //             if(e.hostname == i->text(1))
-    //             {
-    //                 alreadyAdded = true;
-    //                 break;
-    //             }
-    //         }
-
-    //         if(!alreadyAdded)
-    //             server->blacklist.append(ListEntry(i->text(1)));
-    //     }
-    // }
+    // blanked out
     refreshList();
 }
 void DNSServerWindow::on_settingsButton_clicked()

CaptiveDNS/dnsserverwindow.h

@@ -51,6 +51,8 @@ class DNSServerWindow : public QMainWindow
     explicit DNSServerWindow(QWidget *parent = 0);
     ~DNSServerWindow();
 
+    static Ui::DNSServerWindow* mainUi;
+
 signals:
     void displayCache(const std::vector<DNSInfo> &cache);
     void clearSources();
@@ -85,6 +87,7 @@ private slots:
     void on_secondAddButton_clicked();
     void on_settingsButton_clicked();
     void on_cacheViewButton_clicked();
+
 
 private:
     Ui::DNSServerWindow *ui;

CaptiveDNS/dnsserverwindow.ui

@@ -39,7 +39,7 @@
      </widget>
     </item>
     <item row="2" column="0">
-     <widget class="QLabel" name="label_2">
+     <widget class="QLabel" name="dnsStatus">
       <property name="text">
        <string>CaptiveDNS is running!</string>
       </property>

CaptiveDNS/messagesthread.cpp

@@ -66,6 +66,7 @@ void MessagesThread::run()
 
     if(data->dnsServer->startServer(QHostAddress::Any, data->dnsServerPort))
         qDebug() << "DNS server started on address:" << data->dnsServer->serversock.localAddress() << "and port:" << data->dnsServer->serversock.localPort();
+
     if(data->httpServer->startServer(QHostAddress::Any, data->httpServerPort))
         qDebug() << "HTTP server started on address:" << data->httpServer->serverAddress() << "and port:" << data->httpServer->serverPort();
 

CaptiveDNS/messagesthread.h

@@ -56,6 +56,7 @@ class MessagesThread : public QThread
 signals:
     void serversInitialized();
     void androidInit();
+    void displayErrorPopup(QString error);
 };
 
 #endif // MESSAGESTHREAD_H

CaptiveDNS/smalldnsserver.cpp

@@ -1,5 +1,11 @@
 #include "smalldnsserver.h"
 
+#include <QMessageBox>
+#include <iostream>
+#include "dnsserverwindow.h"
+#include "ui_dnsserverwindow.h"
+
+
 /* YourFriendlyDNS - A really awesome multi-platform (lin,win,mac,android) local caching and proxying dns server!
 Copyright (C) 2018  softwareengineer1 @ github.com/softwareengineer1
 Support my work by sending me some Bitcoin or Bitcoin Cash in the value of what you valued one or more of my software projects,
@@ -73,9 +79,33 @@ SmallDNSServer::SmallDNSServer(QObject *parent)
     //     connect(dnscrypt, &DNSCrypt::decryptedLookupDoneSendResponseNow, this, &SmallDNSServer::decryptedLookupDoneSendResponseNow);
 }
 
+void SmallDNSServer::displayErrorPopup(QString error)
+{
+    // run code on the main thread
+    // TODO: not working for some reason, crashes with an error about main threads still
+    // QMetaObject::invokeMethod(this, [error]() {
+    //     QMessageBox::critical(0, "Error", error);
+    // });
+
+    QString msg = "Error: " + error + "\n(Is another DNS server already running?)";
+    DNSServerWindow::mainUi->dnsStatus->setText(msg);
+    DNSServerWindow::mainUi->dnsStatus->setStyleSheet("color: red");
+
+}
+
 bool SmallDNSServer::startServer(QHostAddress address, quint16 port, bool reuse)
 { 
-    return serversock.bind(address, port, reuse ? QUdpSocket::ReuseAddressHint : QUdpSocket::DefaultForPlatform);
+    bool res = serversock.bind(address, port, reuse ? QUdpSocket::ReuseAddressHint : QUdpSocket::DefaultForPlatform);
+
+    printf("SmallDNSServer::startServer() %s:%d\n", address.toString().toUtf8().data(), port);
+    printf("SmallDNSServer::startServer() %s\n", res ? "success" : "failed");
+    if (!res) {
+        printf("SmallDNSServer::startServer() %s\n", serversock.errorString().toUtf8().data());
+        // display qt error popup
+        emit displayErrorPopup(serversock.errorString());
+    }
+
+    return res;
 }
 
 void SmallDNSServer::clearDNSCache()
@@ -240,30 +270,16 @@ void SmallDNSServer::processDNSRequests()
         bool shouldCacheDomain, useDedicatedDNSCryptProviderToResolveV2And3Hosts = false;
         quint32 customIP = ipToRespondWith;
         std::string domain = (char*)dns.domainString.toUtf8().data();
-        if(whitelistmode)
-        {
-            ListEntry *whiteListed = getListEntry(domain, TYPE_WHITELIST);
-            if(whiteListed)
-            {
-                qDebug() << "Matched WhiteList!" << whiteListed->hostname << "to:" << dns.domainString;
-                //It's whitelist mode and in the whitelist, so it should return a real IP! Unless you've manually specified an IP
-                if(whiteListed->ip != 0)
-                    customIP = whiteListed->ip;
-            }
-            shouldCacheDomain = (whiteListed != nullptr);
-        }
-        else
+        ListEntry *blackListed = getListEntry(domain, TYPE_BLACKLIST);
+        if(blackListed)
         {
-            ListEntry *blackListed = getListEntry(domain, TYPE_BLACKLIST);
-            if(blackListed)
-            {
-                qDebug() << "Matched BlackList!" << blackListed->hostname << "to:" << dns.domainString;
-                //It's blacklist mode and in the blacklist, so it should return your custom IP! And your manually specified one if you did specify a particular one
-                if(blackListed->ip != 0)
-                    customIP = blackListed->ip;
-            }
-            shouldCacheDomain = (blackListed == nullptr);
+            qDebug() << "Matched BlackList!" << blackListed->hostname << "to:" << dns.domainString;
+            //It's blacklist mode and in the blacklist, so it should return your custom IP! And your manually specified one if you did specify a particular one
+            if(blackListed->ip != 0)
+                customIP = blackListed->ip;
         }
+        shouldCacheDomain = (blackListed == nullptr);
+
         if(shouldCacheDomain)
         {
             //Trying to exclude local hostnames from leaking
@@ -313,27 +329,12 @@ void SmallDNSServer::processDNSRequests()
                 dns.senderPort = senderPort;
                 dns.ttl = dnsTTL;
 
-                if(dnscryptEnabled)
-                {
-                    qDebug() << "Making encrypted DNS request type:" << dns.question.qtype << "for domain:" << dns.domainString << "request id:" << dns.header.id << "datagram:" << datagram;
-                    if(useDedicatedDNSCryptProviderToResolveV2And3Hosts)
-                    {
-                        // dnscrypt->setProvider(dedicatedDNSCrypter);
-                        qDebug() << "Using dedicated DNSCrypt provider to resolve DoH/DoTLS provider's host:" << dns.domainString;
-                    }
-                    // else 
-                        // dnscrypt->setProvider(selectRandomDNSCryptServer());
-
-                    // dnscrypt->makeEncryptedRequest(dns);
-                }
-                else
-                {
-                    qDebug() << "Making DNS request type:" << dns.question.qtype << "for domain:" << dns.domainString << "request id:" << dns.header.id << "datagram:" << datagram;
-                    QString server = selectRandomDNSServer();
-                    quint16 serverPort = DNSInfo::extractPort(server);
-                    if(serverPort == 0 || serverPort == 443) serverPort = 53;
-                    clientsock.writeDatagram(datagram, QHostAddress(server), serverPort);
-                }
+
+                qDebug() << "Making DNS request type:" << dns.question.qtype << "for domain:" << dns.domainString << "request id:" << dns.header.id << "datagram:" << datagram;
+                QString server = selectRandomDNSServer();
+                quint16 serverPort = DNSInfo::extractPort(server);
+                if(serverPort == 0 || serverPort == 443) serverPort = 53;
+                clientsock.writeDatagram(datagram, QHostAddress(server), serverPort);
 
                 InitialResponse *ir = new InitialResponse(dns);
                 if(ir)

CaptiveDNS/smalldnsserver.h

@@ -74,6 +74,10 @@ bool GeneralTextCompare(
         char cAltTerminator = '\0'    // For function names, for example, you can stop at the first '('
 );
 
+namespace Ui {
+class DNSServerWindow;
+}
+
 class SmallDNSServer : public QObject
 {
     Q_OBJECT
@@ -98,6 +102,7 @@ class SmallDNSServer : public QObject
     // DNSCrypt *dnscrypt;
 
 private:
+    Ui::DNSServerWindow *ui;
     ListEntry* getListEntry(const std::string &tame, int listType);
     DNSInfo* getCachedEntry(const QString &byDomain, quint16 andType);
     void parseAndRespond(QByteArray &datagram, DNSInfo &dns);
@@ -119,6 +124,7 @@ public slots:
     void clearDNSCache();
     void deleteEntriesFromCache(std::vector<ListEntry> entries);
     void decryptedLookupDoneSendResponseNow(QByteArray decryptedResponse, DNSInfo &dns);
+    void displayErrorPopup(QString error);
 
 private slots:
     void processDNSRequests();

CaptiveDNS/smallhttpserver.cpp

@@ -135,7 +135,7 @@ void SmallHTTPServer::createLanding()
         <li><a href=\"https://duckduckgo.com\">DuckDuckGo</a></li>\n\
         <li><a href=\"https://startpage.com\">StartPage</a></li>\n\
     </ul>\n\
-    <p>To customize this page, press \"Edit Landing Page\" in the CaptiveDNS app, and then open `landing.html` in a text editor.</p>\n\
+    <p>To customize this page, press \"Edit Landing Page\" in the CaptiveDNS app, and then open <code>landing.html</code> in a text editor.</p>\n\
     <p>For source code and license information, see <a href=\"https://github.com/browsedns/captivedns\">here</a>.</p>\n\
     <p><a href=\"javascript:window.location.reload();\">Reload Page</a></p>\n\
 </body></html>";

README.md

@@ -4,7 +4,8 @@ An app to help display a [captive portal](https://en.wikipedia.org/wiki/Captive_
 Based on [YourFriendlyDNS](https://github.com/softwareengineer1/YourFriendlyDNS/), which contains many more advanced options for other self-hosted DNS use cases.
 
 ## Screenshots
-<img src="preview.png" width="317" alt="CaptiveDNS Screenshot" />
+<img src="preview.png" width="317" alt="CaptiveDNS Window Screenshot" /> <img src="preview2.png" width="220" alt="CaptiveDNS Landing page" />
+
 
 ## Captured Domains