# Enable L2TP and add a tunnel

This sample application demonstrates how to enable L2TP and add a tunnel.

1. Implement initialization callback and get get the DataFactory instance

Optionally, initialization callback can be provided with get manager instance.
Data factory will call callback when manager initialization is complete.

auto initCb = [&](telux::common::ServiceStatus status) {
       std::lock_guard<std::mutex> lock(mtx);
       status_ = status;
       initCv.notify_all();
    };
    
    auto &dataFactory = telux::data::DataFactory::getInstance();
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2. Get the L2tpManager instances

std::unique_lock<std::mutex> lck(mtx);
    auto dataL2tpMgr  = dataFactory.getL2tpManager(initCb);
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3. Wait for L2tpManager initialization to be complete

initCv.wait(lck);
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3.1 Check L2tpManager initialization state

If L2tpManager initialization failed, new initialization attempt can be accomplished
by calling step 2. If L2tpManager initialization succeed, proceed to step 4

if (status_ == telux::common::ServiceStatus::SERVICE_AVAILABLE) {
       // Go to step 4
    }
    else {
       //Go to step 2 for another initialization attempt
    }
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4. Optionally, instantiate setConfig callback instance

auto setConfigCb = [&setConfigPass, &promise](telux::common::ErrorCode error) {
    std::cout << std::endl << std::endl;
    std::cout << "CALLBACK: "
              << "setConfig Response"
              << (error == telux::common::ErrorCode::SUCCESS ? " is successful" : " failed");
    };
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5. Set L2TP configuration

bool enable = true;        //Enable L2TP
    bool enableMss = true;     // Enable MSS Clamping
    bool enableMtu = true;     // Enable custom size MTU
    int mtuSize = 0;           // Set MTU size to default 1422 bytes, otherwise set desired mtu size
    dataL2tpMgr->setConfig(enable, enableMss, enableMtu, setConfigCb, mtuSize);
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6. Configure L2TP tunnel and session

std::cout << "L2TP Set Configuration succeeded ... Adding Tunnel" << std::endl;
    telux::data::net::L2tpTunnelConfig l2tpTunnelConfig;
    
    l2tpTunnelConfig.locIface = "eth0.1"; //Set interface name to eth0.x where x is vlan id
    l2tpTunnelConfig.prot = static_cast<telux::data::net::L2tpProtocol>(2); //Set protocol to UDP
    l2tpTunnelConfig.locId = 1;  //Set local tunnel id
    l2tpTunnelConfig.peerId = 1; //Set peer tunnel id
    l2tpTunnelConfig.localUdpPort = 500;   //Set local UDP port if UDP protocol is selected above
    l2tpTunnelConfig.peerUdpPort = 100;    //Set peer UDP port if UDP protocol is selected above
    l2tpTunnelConfig.ipType =  static_cast<telux::data::IpFamilyType>(6); //Set Ip family type
    l2tpTunnelConfig.peerIpv6Addr =  "fe80::b044::c0ff::fec4";  // Set peer Ip address
    telux::data::net::L2tpSessionConfig l2tpSessionConfig;
    l2tpSessionConfig.locId = 1;   //Set local session id
    l2tpSessionConfig.peerId = 1;  //Set peer session id
    l2tpTunnelConfig.sessionConfig.emplace_back(l2tpSessionConfig); // Add session to tunnel config
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7. Optionally, instantiate addTunnel callback instance

auto addTunnelCb = [&setConfigPass, &promise](telux::common::ErrorCode error) {
       std::cout << std::endl << std::endl;
       std::cout << "CALLBACK: "
                 << "addTunnel Response"
                 << (error == telux::common::ErrorCode::SUCCESS ? " is successful" : " failed")
                 << ". ErrorCode: " << static_cast<int>(error) << "\n";
    };
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8. Add the tunnel to L2TP

dataL2tpMgr->addTunnel(l2tpTunnelConfig, addTunnelCb);
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Last Published: Jun 24, 2026

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