fix: allocate utun-pattern interface names on macOS

client/vpnConnection.cpp

@@ -125,13 +125,29 @@ Vpn::ConnectionState VpnConnection::connectionState() const
 
 QString VpnConnection::allocateIfname()
 {
+#ifdef Q_OS_MACOS
+    QString kernelAssigned;
+    IpcClient::withInterface([&kernelAssigned](QSharedPointer<IpcInterfaceReplica> iface) {
+        auto reply = iface->reserveUtunName();
+        if (reply.waitForFinished(2000)) {
+            kernelAssigned = reply.returnValue();
+        }
+    });
+    if (kernelAssigned.isEmpty() || m_ifnamesInUse.contains(kernelAssigned)) {
+        qCritical() << "allocateIfname: kernel utun reservation failed";
+        return QString();
+    }
+    m_ifnamesInUse.insert(kernelAssigned);
+    return kernelAssigned;
+#else
     for (int i = 0; ; ++i) {
-        const QString name = QStringLiteral("amn") + QString::number(i);
+        const QString name = QStringLiteral("amn%1").arg(i);
         if (!m_ifnamesInUse.contains(name)) {
             m_ifnamesInUse.insert(name);
             return name;
         }
     }
+#endif
 }
 
 void VpnConnection::releaseIfname(const QString& ifname)
@@ -171,6 +187,11 @@ void VpnConnection::connectToVpn(const QString &serverId, DockerContainer contai
     const bool isXray = VpnProtocol::isXrayBased(container);
     const bool useTunnelPath = isWg || isXray;
     const QString preAllocatedIfname = useTunnelPath ? allocateIfname() : QString();
+    if (useTunnelPath && preAllocatedIfname.isEmpty()) {
+        setConnectionState(Vpn::ConnectionState::Error);
+        emit vpnProtocolError(ErrorCode::AmneziaServiceConnectionFailed);
+        return;
+    }
 
     if (m_active
         && m_connectionState == Vpn::ConnectionState::Connected

ipc/ipc_interface.rep

@@ -31,6 +31,8 @@ class IpcInterface
     SLOT( bool createTun(const QString &dev, const QString &subnet) );
     SLOT( bool deleteTun(const QString &dev) );
 
+    SLOT( QString reserveUtunName() );
+
     SLOT( bool applyAdapterAddress(const QString &ifname, const QString &ipv4, const QString &ipv6) );
 
     SLOT( bool removeAdapterAddress(const QString &ifname, const QString &ipv4, const QString &ipv6) );

ipc/ipcserver.cpp

@@ -35,6 +35,17 @@
     #include "tapcontroller_win.h"
 #endif
 
+#ifdef Q_OS_MAC
+    #include <sys/socket.h>
+    #include <sys/sys_domain.h>
+    #include <sys/kern_control.h>
+    #include <sys/ioctl.h>
+    #include <net/if.h>
+    #include <net/if_utun.h>
+    #include <unistd.h>
+    #include <cstring>
+#endif
+
 
 IpcServer::IpcServer(QObject *parent) : IpcInterfaceSource(parent)
 {
@@ -215,6 +226,53 @@ bool IpcServer::deleteTun(const QString &dev)
     return Router::deleteTun(dev);
 }
 
+QString IpcServer::reserveUtunName()
+{
+#ifdef Q_OS_MAC
+    int fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
+    if (fd < 0) {
+        qWarning() << "reserveUtunName: socket() failed:" << strerror(errno);
+        return QString();
+    }
+
+    struct ctl_info info;
+    std::memset(&info, 0, sizeof(info));
+    std::strncpy(info.ctl_name, UTUN_CONTROL_NAME, sizeof(info.ctl_name) - 1);
+    if (ioctl(fd, CTLIOCGINFO, &info) < 0) {
+        qWarning() << "reserveUtunName: CTLIOCGINFO failed:" << strerror(errno);
+        ::close(fd);
+        return QString();
+    }
+
+    struct sockaddr_ctl addr;
+    std::memset(&addr, 0, sizeof(addr));
+    addr.sc_len = sizeof(addr);
+    addr.sc_family = AF_SYSTEM;
+    addr.ss_sysaddr = AF_SYS_CONTROL;
+    addr.sc_id = info.ctl_id;
+    addr.sc_unit = 0;
+
+    if (::connect(fd, reinterpret_cast<struct sockaddr*>(&addr), sizeof(addr)) < 0) {
+        qWarning() << "reserveUtunName: connect() failed:" << strerror(errno);
+        ::close(fd);
+        return QString();
+    }
+
+    char ifname[IFNAMSIZ] = {0};
+    socklen_t len = sizeof(ifname);
+    if (getsockopt(fd, SYSPROTO_CONTROL, UTUN_OPT_IFNAME, ifname, &len) < 0) {
+        qWarning() << "reserveUtunName: getsockopt UTUN_OPT_IFNAME failed:" << strerror(errno);
+        ::close(fd);
+        return QString();
+    }
+
+    ::close(fd);
+    return QString::fromUtf8(ifname);
+#else
+    return QString();
+#endif
+}
+
 bool IpcServer::applyAdapterAddress(const QString &ifname, const QString &ipv4, const QString &ipv6)
 {
 #ifdef Q_OS_WIN

ipc/ipcserver.h

@@ -43,6 +43,7 @@ public:
     virtual void setLogsEnabled(bool enabled) override;
     virtual bool createTun(const QString &dev, const QString &subnet) override;
     virtual bool deleteTun(const QString &dev) override;
+    virtual QString reserveUtunName() override;
     virtual bool applyAdapterAddress(const QString &ifname, const QString &ipv4, const QString &ipv6) override;
     virtual bool removeAdapterAddress(const QString &ifname, const QString &ipv4, const QString &ipv6) override;
     virtual bool StartRoutingIpv6() override;