4 files changed, 940 insertions, 116 deletions

diff --git a/src/core/hle/service/ldn/lan_discovery.cpp b/src/core/hle/service/ldn/lan_discovery.cpp
new file mode 100644
index 000000000..b04c99077
--- /dev/null
+++ b/src/core/hle/service/ldn/lan_discovery.cpp
@@ -0,0 +1,644 @@
+// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/hle/service/ldn/lan_discovery.h"
+#include "core/internal_network/network.h"
+#include "core/internal_network/network_interface.h"
+
+namespace Service::LDN {
+
+LanStation::LanStation(s8 node_id_, LANDiscovery* discovery_)
+    : node_info(nullptr), status(NodeStatus::Disconnected), node_id(node_id_),
+      discovery(discovery_) {}
+
+LanStation::~LanStation() = default;
+
+NodeStatus LanStation::GetStatus() const {
+    return status;
+}
+
+void LanStation::OnClose() {
+    LOG_INFO(Service_LDN, "OnClose {}", node_id);
+    Reset();
+    discovery->UpdateNodes();
+}
+
+void LanStation::Reset() {
+    status = NodeStatus::Disconnected;
+};
+
+void LanStation::OverrideInfo() {
+    bool connected = GetStatus() == NodeStatus::Connected;
+    node_info->node_id = node_id;
+    node_info->is_connected = connected ? 1 : 0;
+}
+
+LANDiscovery::LANDiscovery(Network::RoomNetwork& room_network_)
+    : stations({{{1, this}, {2, this}, {3, this}, {4, this}, {5, this}, {6, this}, {7, this}}}),
+      room_network{room_network_} {
+    LOG_INFO(Service_LDN, "LANDiscovery");
+}
+
+LANDiscovery::~LANDiscovery() {
+    LOG_INFO(Service_LDN, "~LANDiscovery");
+    if (inited) {
+        Result rc = Finalize();
+        LOG_INFO(Service_LDN, "Finalize: {}", rc.raw);
+    }
+}
+
+void LANDiscovery::InitNetworkInfo() {
+    network_info.common.bssid = GetFakeMac();
+    network_info.common.channel = WifiChannel::Wifi24_6;
+    network_info.common.link_level = LinkLevel::Good;
+    network_info.common.network_type = PackedNetworkType::Ldn;
+    network_info.common.ssid = fake_ssid;
+
+    auto& nodes = network_info.ldn.nodes;
+    for (std::size_t i = 0; i < NodeCountMax; i++) {
+        nodes[i].node_id = static_cast<s8>(i);
+        nodes[i].is_connected = 0;
+    }
+}
+
+void LANDiscovery::InitNodeStateChange() {
+    for (auto& node_update : nodeChanges) {
+        node_update.state_change = NodeStateChange::None;
+    }
+    for (auto& node_state : node_last_states) {
+        node_state = 0;
+    }
+}
+
+State LANDiscovery::GetState() const {
+    return state;
+}
+
+void LANDiscovery::SetState(State new_state) {
+    state = new_state;
+}
+
+Result LANDiscovery::GetNetworkInfo(NetworkInfo& out_network) const {
+    if (state == State::AccessPointCreated || state == State::StationConnected) {
+        std::memcpy(&out_network, &network_info, sizeof(network_info));
+        return ResultSuccess;
+    }
+
+    return ResultBadState;
+}
+
+Result LANDiscovery::GetNetworkInfo(NetworkInfo& out_network,
+                                    std::vector<NodeLatestUpdate>& out_updates,
+                                    std::size_t buffer_count) {
+    if (buffer_count > NodeCountMax) {
+        return ResultInvalidBufferCount;
+    }
+
+    if (state == State::AccessPointCreated || state == State::StationConnected) {
+        std::memcpy(&out_network, &network_info, sizeof(network_info));
+        for (std::size_t i = 0; i < buffer_count; i++) {
+            out_updates[i].state_change = nodeChanges[i].state_change;
+            nodeChanges[i].state_change = NodeStateChange::None;
+        }
+        return ResultSuccess;
+    }
+
+    return ResultBadState;
+}
+
+DisconnectReason LANDiscovery::GetDisconnectReason() const {
+    return disconnect_reason;
+}
+
+Result LANDiscovery::Scan(std::vector<NetworkInfo>& networks, u16& count,
+                          const ScanFilter& filter) {
+    if (!IsFlagSet(filter.flag, ScanFilterFlag::NetworkType) ||
+        filter.network_type <= NetworkType::All) {
+        if (!IsFlagSet(filter.flag, ScanFilterFlag::Ssid) && filter.ssid.length >= SsidLengthMax) {
+            return ResultBadInput;
+        }
+    }
+
+    {
+        std::scoped_lock lock{packet_mutex};
+        scan_results.clear();
+
+        SendBroadcast(Network::LDNPacketType::Scan);
+    }
+
+    LOG_INFO(Service_LDN, "Waiting for scan replies");
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+
+    std::scoped_lock lock{packet_mutex};
+    for (const auto& [key, info] : scan_results) {
+        if (count >= networks.size()) {
+            break;
+        }
+
+        if (IsFlagSet(filter.flag, ScanFilterFlag::LocalCommunicationId)) {
+            if (filter.network_id.intent_id.local_communication_id !=
+                info.network_id.intent_id.local_communication_id) {
+                continue;
+            }
+        }
+        if (IsFlagSet(filter.flag, ScanFilterFlag::SessionId)) {
+            if (filter.network_id.session_id != info.network_id.session_id) {
+                continue;
+            }
+        }
+        if (IsFlagSet(filter.flag, ScanFilterFlag::NetworkType)) {
+            if (filter.network_type != static_cast<NetworkType>(info.common.network_type)) {
+                continue;
+            }
+        }
+        if (IsFlagSet(filter.flag, ScanFilterFlag::Ssid)) {
+            if (filter.ssid != info.common.ssid) {
+                continue;
+            }
+        }
+        if (IsFlagSet(filter.flag, ScanFilterFlag::SceneId)) {
+            if (filter.network_id.intent_id.scene_id != info.network_id.intent_id.scene_id) {
+                continue;
+            }
+        }
+
+        networks[count++] = info;
+    }
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::SetAdvertiseData(std::vector<u8>& data) {
+    std::scoped_lock lock{packet_mutex};
+    std::size_t size = data.size();
+    if (size > AdvertiseDataSizeMax) {
+        return ResultAdvertiseDataTooLarge;
+    }
+
+    std::memcpy(network_info.ldn.advertise_data.data(), data.data(), size);
+    network_info.ldn.advertise_data_size = static_cast<u16>(size);
+
+    UpdateNodes();
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::OpenAccessPoint() {
+    std::scoped_lock lock{packet_mutex};
+    disconnect_reason = DisconnectReason::None;
+    if (state == State::None) {
+        return ResultBadState;
+    }
+
+    ResetStations();
+    SetState(State::AccessPointOpened);
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::CloseAccessPoint() {
+    std::scoped_lock lock{packet_mutex};
+    if (state == State::None) {
+        return ResultBadState;
+    }
+
+    if (state == State::AccessPointCreated) {
+        DestroyNetwork();
+    }
+
+    ResetStations();
+    SetState(State::Initialized);
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::OpenStation() {
+    std::scoped_lock lock{packet_mutex};
+    disconnect_reason = DisconnectReason::None;
+    if (state == State::None) {
+        return ResultBadState;
+    }
+
+    ResetStations();
+    SetState(State::StationOpened);
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::CloseStation() {
+    std::scoped_lock lock{packet_mutex};
+    if (state == State::None) {
+        return ResultBadState;
+    }
+
+    if (state == State::StationConnected) {
+        Disconnect();
+    }
+
+    ResetStations();
+    SetState(State::Initialized);
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::CreateNetwork(const SecurityConfig& security_config,
+                                   const UserConfig& user_config,
+                                   const NetworkConfig& network_config) {
+    std::scoped_lock lock{packet_mutex};
+
+    if (state != State::AccessPointOpened) {
+        return ResultBadState;
+    }
+
+    InitNetworkInfo();
+    network_info.ldn.node_count_max = network_config.node_count_max;
+    network_info.ldn.security_mode = security_config.security_mode;
+
+    if (network_config.channel == WifiChannel::Default) {
+        network_info.common.channel = WifiChannel::Wifi24_6;
+    } else {
+        network_info.common.channel = network_config.channel;
+    }
+
+    std::independent_bits_engine<std::mt19937, 64, u64> bits_engine;
+    network_info.network_id.session_id.high = bits_engine();
+    network_info.network_id.session_id.low = bits_engine();
+    network_info.network_id.intent_id = network_config.intent_id;
+
+    NodeInfo& node0 = network_info.ldn.nodes[0];
+    const Result rc2 = GetNodeInfo(node0, user_config, network_config.local_communication_version);
+    if (rc2.IsError()) {
+        return ResultAccessPointConnectionFailed;
+    }
+
+    SetState(State::AccessPointCreated);
+
+    InitNodeStateChange();
+    node0.is_connected = 1;
+    UpdateNodes();
+
+    return rc2;
+}
+
+Result LANDiscovery::DestroyNetwork() {
+    for (auto local_ip : connected_clients) {
+        SendPacket(Network::LDNPacketType::DestroyNetwork, local_ip);
+    }
+
+    ResetStations();
+
+    SetState(State::AccessPointOpened);
+    LanEvent();
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::Connect(const NetworkInfo& network_info_, const UserConfig& user_config,
+                             u16 local_communication_version) {
+    std::scoped_lock lock{packet_mutex};
+    if (network_info_.ldn.node_count == 0) {
+        return ResultInvalidNodeCount;
+    }
+
+    Result rc = GetNodeInfo(node_info, user_config, local_communication_version);
+    if (rc.IsError()) {
+        return ResultConnectionFailed;
+    }
+
+    Ipv4Address node_host = network_info_.ldn.nodes[0].ipv4_address;
+    std::reverse(std::begin(node_host), std::end(node_host)); // htonl
+    host_ip = node_host;
+    SendPacket(Network::LDNPacketType::Connect, node_info, *host_ip);
+
+    InitNodeStateChange();
+
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::Disconnect() {
+    if (host_ip) {
+        SendPacket(Network::LDNPacketType::Disconnect, node_info, *host_ip);
+    }
+
+    SetState(State::StationOpened);
+    LanEvent();
+
+    return ResultSuccess;
+}
+
+Result LANDiscovery::Initialize(LanEventFunc lan_event, bool listening) {
+    std::scoped_lock lock{packet_mutex};
+    if (inited) {
+        return ResultSuccess;
+    }
+
+    for (auto& station : stations) {
+        station.discovery = this;
+        station.node_info = &network_info.ldn.nodes[station.node_id];
+        station.Reset();
+    }
+
+    connected_clients.clear();
+    LanEvent = lan_event;
+
+    SetState(State::Initialized);
+
+    inited = true;
+    return ResultSuccess;
+}
+
+Result LANDiscovery::Finalize() {
+    std::scoped_lock lock{packet_mutex};
+    Result rc = ResultSuccess;
+
+    if (inited) {
+        if (state == State::AccessPointCreated) {
+            DestroyNetwork();
+        }
+        if (state == State::StationConnected) {
+            Disconnect();
+        }
+
+        ResetStations();
+        inited = false;
+    }
+
+    SetState(State::None);
+
+    return rc;
+}
+
+void LANDiscovery::ResetStations() {
+    for (auto& station : stations) {
+        station.Reset();
+    }
+    connected_clients.clear();
+}
+
+void LANDiscovery::UpdateNodes() {
+    u8 count = 0;
+    for (auto& station : stations) {
+        bool connected = station.GetStatus() == NodeStatus::Connected;
+        if (connected) {
+            count++;
+        }
+        station.OverrideInfo();
+    }
+    network_info.ldn.node_count = count + 1;
+
+    for (auto local_ip : connected_clients) {
+        SendPacket(Network::LDNPacketType::SyncNetwork, network_info, local_ip);
+    }
+
+    OnNetworkInfoChanged();
+}
+
+void LANDiscovery::OnSyncNetwork(const NetworkInfo& info) {
+    network_info = info;
+    if (state == State::StationOpened) {
+        SetState(State::StationConnected);
+    }
+    OnNetworkInfoChanged();
+}
+
+void LANDiscovery::OnDisconnectFromHost() {
+    LOG_INFO(Service_LDN, "OnDisconnectFromHost state: {}", static_cast<int>(state));
+    host_ip = std::nullopt;
+    if (state == State::StationConnected) {
+        SetState(State::StationOpened);
+        LanEvent();
+    }
+}
+
+void LANDiscovery::OnNetworkInfoChanged() {
+    if (IsNodeStateChanged()) {
+        LanEvent();
+    }
+    return;
+}
+
+Network::IPv4Address LANDiscovery::GetLocalIp() const {
+    Network::IPv4Address local_ip{0xFF, 0xFF, 0xFF, 0xFF};
+    if (auto room_member = room_network.GetRoomMember().lock()) {
+        if (room_member->IsConnected()) {
+            local_ip = room_member->GetFakeIpAddress();
+        }
+    }
+    return local_ip;
+}
+
+template <typename Data>
+void LANDiscovery::SendPacket(Network::LDNPacketType type, const Data& data,
+                              Ipv4Address remote_ip) {
+    Network::LDNPacket packet;
+    packet.type = type;
+
+    packet.broadcast = false;
+    packet.local_ip = GetLocalIp();
+    packet.remote_ip = remote_ip;
+
+    packet.data.clear();
+    packet.data.resize(sizeof(data));
+    std::memcpy(packet.data.data(), &data, sizeof(data));
+    SendPacket(packet);
+}
+
+void LANDiscovery::SendPacket(Network::LDNPacketType type, Ipv4Address remote_ip) {
+    Network::LDNPacket packet;
+    packet.type = type;
+
+    packet.broadcast = false;
+    packet.local_ip = GetLocalIp();
+    packet.remote_ip = remote_ip;
+
+    packet.data.clear();
+    SendPacket(packet);
+}
+
+template <typename Data>
+void LANDiscovery::SendBroadcast(Network::LDNPacketType type, const Data& data) {
+    Network::LDNPacket packet;
+    packet.type = type;
+
+    packet.broadcast = true;
+    packet.local_ip = GetLocalIp();
+
+    packet.data.clear();
+    packet.data.resize(sizeof(data));
+    std::memcpy(packet.data.data(), &data, sizeof(data));
+    SendPacket(packet);
+}
+
+void LANDiscovery::SendBroadcast(Network::LDNPacketType type) {
+    Network::LDNPacket packet;
+    packet.type = type;
+
+    packet.broadcast = true;
+    packet.local_ip = GetLocalIp();
+
+    packet.data.clear();
+    SendPacket(packet);
+}
+
+void LANDiscovery::SendPacket(const Network::LDNPacket& packet) {
+    if (auto room_member = room_network.GetRoomMember().lock()) {
+        if (room_member->IsConnected()) {
+            room_member->SendLdnPacket(packet);
+        }
+    }
+}
+
+void LANDiscovery::ReceivePacket(const Network::LDNPacket& packet) {
+    std::scoped_lock lock{packet_mutex};
+    switch (packet.type) {
+    case Network::LDNPacketType::Scan: {
+        LOG_INFO(Frontend, "Scan packet received!");
+        if (state == State::AccessPointCreated) {
+            // Reply to the sender
+            SendPacket(Network::LDNPacketType::ScanResp, network_info, packet.local_ip);
+        }
+        break;
+    }
+    case Network::LDNPacketType::ScanResp: {
+        LOG_INFO(Frontend, "ScanResp packet received!");
+
+        NetworkInfo info{};
+        std::memcpy(&info, packet.data.data(), sizeof(NetworkInfo));
+        scan_results.insert({info.common.bssid, info});
+
+        break;
+    }
+    case Network::LDNPacketType::Connect: {
+        LOG_INFO(Frontend, "Connect packet received!");
+
+        NodeInfo info{};
+        std::memcpy(&info, packet.data.data(), sizeof(NodeInfo));
+
+        connected_clients.push_back(packet.local_ip);
+
+        for (LanStation& station : stations) {
+            if (station.status != NodeStatus::Connected) {
+                *station.node_info = info;
+                station.status = NodeStatus::Connected;
+                break;
+            }
+        }
+
+        UpdateNodes();
+
+        break;
+    }
+    case Network::LDNPacketType::Disconnect: {
+        LOG_INFO(Frontend, "Disconnect packet received!");
+
+        connected_clients.erase(
+            std::remove(connected_clients.begin(), connected_clients.end(), packet.local_ip),
+            connected_clients.end());
+
+        NodeInfo info{};
+        std::memcpy(&info, packet.data.data(), sizeof(NodeInfo));
+
+        for (LanStation& station : stations) {
+            if (station.status == NodeStatus::Connected &&
+                station.node_info->mac_address == info.mac_address) {
+                station.OnClose();
+                break;
+            }
+        }
+
+        break;
+    }
+    case Network::LDNPacketType::DestroyNetwork: {
+        ResetStations();
+        OnDisconnectFromHost();
+        break;
+    }
+    case Network::LDNPacketType::SyncNetwork: {
+        if (state == State::StationOpened || state == State::StationConnected) {
+            LOG_INFO(Frontend, "SyncNetwork packet received!");
+            NetworkInfo info{};
+            std::memcpy(&info, packet.data.data(), sizeof(NetworkInfo));
+
+            OnSyncNetwork(info);
+        } else {
+            LOG_INFO(Frontend, "SyncNetwork packet received but in wrong State!");
+        }
+
+        break;
+    }
+    default: {
+        LOG_INFO(Frontend, "ReceivePacket unhandled type {}", static_cast<int>(packet.type));
+        break;
+    }
+    }
+}
+
+bool LANDiscovery::IsNodeStateChanged() {
+    bool changed = false;
+    const auto& nodes = network_info.ldn.nodes;
+    for (int i = 0; i < NodeCountMax; i++) {
+        if (nodes[i].is_connected != node_last_states[i]) {
+            if (nodes[i].is_connected) {
+                nodeChanges[i].state_change |= NodeStateChange::Connect;
+            } else {
+                nodeChanges[i].state_change |= NodeStateChange::Disconnect;
+            }
+            node_last_states[i] = nodes[i].is_connected;
+            changed = true;
+        }
+    }
+    return changed;
+}
+
+bool LANDiscovery::IsFlagSet(ScanFilterFlag flag, ScanFilterFlag search_flag) const {
+    const auto flag_value = static_cast<u32>(flag);
+    const auto search_flag_value = static_cast<u32>(search_flag);
+    return (flag_value & search_flag_value) == search_flag_value;
+}
+
+int LANDiscovery::GetStationCount() {
+    int count = 0;
+    for (const auto& station : stations) {
+        if (station.GetStatus() != NodeStatus::Disconnected) {
+            count++;
+        }
+    }
+
+    return count;
+}
+
+MacAddress LANDiscovery::GetFakeMac() const {
+    MacAddress mac{};
+    mac.raw[0] = 0x02;
+    mac.raw[1] = 0x00;
+
+    const auto ip = GetLocalIp();
+    memcpy(mac.raw.data() + 2, &ip, sizeof(ip));
+
+    return mac;
+}
+
+Result LANDiscovery::GetNodeInfo(NodeInfo& node, const UserConfig& userConfig,
+                                 u16 localCommunicationVersion) {
+    const auto network_interface = Network::GetSelectedNetworkInterface();
+
+    if (!network_interface) {
+        LOG_ERROR(Service_LDN, "No network interface available");
+        return ResultNoIpAddress;
+    }
+
+    node.mac_address = GetFakeMac();
+    node.is_connected = 1;
+    std::memcpy(node.user_name.data(), userConfig.user_name.data(), UserNameBytesMax + 1);
+    node.local_communication_version = localCommunicationVersion;
+
+    Ipv4Address current_address = GetLocalIp();
+    std::reverse(std::begin(current_address), std::end(current_address)); // ntohl
+    node.ipv4_address = current_address;
+
+    return ResultSuccess;
+}
+
+} // namespace Service::LDN
diff --git a/src/core/hle/service/ldn/lan_discovery.h b/src/core/hle/service/ldn/lan_discovery.h
new file mode 100644
index 000000000..255342456
--- /dev/null
+++ b/src/core/hle/service/ldn/lan_discovery.h
@@ -0,0 +1,133 @@
+// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <array>
+#include <cstring>
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <optional>
+#include <random>
+#include <thread>
+#include <unordered_map>
+
+#include "common/logging/log.h"
+#include "common/socket_types.h"
+#include "core/hle/result.h"
+#include "core/hle/service/ldn/ldn_results.h"
+#include "core/hle/service/ldn/ldn_types.h"
+#include "network/network.h"
+
+namespace Service::LDN {
+
+class LANDiscovery;
+
+class LanStation {
+public:
+    LanStation(s8 node_id_, LANDiscovery* discovery_);
+    ~LanStation();
+
+    void OnClose();
+    NodeStatus GetStatus() const;
+    void Reset();
+    void OverrideInfo();
+
+protected:
+    friend class LANDiscovery;
+    NodeInfo* node_info;
+    NodeStatus status;
+    s8 node_id;
+    LANDiscovery* discovery;
+};
+
+class LANDiscovery {
+public:
+    typedef std::function<void()> LanEventFunc;
+
+    LANDiscovery(Network::RoomNetwork& room_network_);
+    ~LANDiscovery();
+
+    State GetState() const;
+    void SetState(State new_state);
+
+    Result GetNetworkInfo(NetworkInfo& out_network) const;
+    Result GetNetworkInfo(NetworkInfo& out_network, std::vector<NodeLatestUpdate>& out_updates,
+                          std::size_t buffer_count);
+
+    DisconnectReason GetDisconnectReason() const;
+    Result Scan(std::vector<NetworkInfo>& networks, u16& count, const ScanFilter& filter);
+    Result SetAdvertiseData(std::vector<u8>& data);
+
+    Result OpenAccessPoint();
+    Result CloseAccessPoint();
+
+    Result OpenStation();
+    Result CloseStation();
+
+    Result CreateNetwork(const SecurityConfig& security_config, const UserConfig& user_config,
+                         const NetworkConfig& network_config);
+    Result DestroyNetwork();
+
+    Result Connect(const NetworkInfo& network_info_, const UserConfig& user_config,
+                   u16 local_communication_version);
+    Result Disconnect();
+
+    Result Initialize(LanEventFunc lan_event = empty_func, bool listening = true);
+    Result Finalize();
+
+    void ReceivePacket(const Network::LDNPacket& packet);
+
+protected:
+    friend class LanStation;
+
+    void InitNetworkInfo();
+    void InitNodeStateChange();
+
+    void ResetStations();
+    void UpdateNodes();
+
+    void OnSyncNetwork(const NetworkInfo& info);
+    void OnDisconnectFromHost();
+    void OnNetworkInfoChanged();
+
+    bool IsNodeStateChanged();
+    bool IsFlagSet(ScanFilterFlag flag, ScanFilterFlag search_flag) const;
+    int GetStationCount();
+    MacAddress GetFakeMac() const;
+    Result GetNodeInfo(NodeInfo& node, const UserConfig& user_config,
+                       u16 local_communication_version);
+
+    Network::IPv4Address GetLocalIp() const;
+    template <typename Data>
+    void SendPacket(Network::LDNPacketType type, const Data& data, Ipv4Address remote_ip);
+    void SendPacket(Network::LDNPacketType type, Ipv4Address remote_ip);
+    template <typename Data>
+    void SendBroadcast(Network::LDNPacketType type, const Data& data);
+    void SendBroadcast(Network::LDNPacketType type);
+    void SendPacket(const Network::LDNPacket& packet);
+
+    static const LanEventFunc empty_func;
+    const Ssid fake_ssid{"YuzuFakeSsidForLdn"};
+
+    bool inited{};
+    std::mutex packet_mutex;
+    std::array<LanStation, StationCountMax> stations;
+    std::array<NodeLatestUpdate, NodeCountMax> nodeChanges{};
+    std::array<u8, NodeCountMax> node_last_states{};
+    std::unordered_map<MacAddress, NetworkInfo, MACAddressHash> scan_results{};
+    NodeInfo node_info{};
+    NetworkInfo network_info{};
+    State state{State::None};
+    DisconnectReason disconnect_reason{DisconnectReason::None};
+
+    // TODO (flTobi): Should this be an std::set?
+    std::vector<Ipv4Address> connected_clients;
+    std::optional<Ipv4Address> host_ip = std::nullopt;
+
+    LanEventFunc LanEvent;
+
+    Network::RoomNetwork& room_network;
+};
+} // namespace Service::LDN
diff --git a/src/core/hle/service/ldn/ldn.cpp b/src/core/hle/service/ldn/ldn.cpp
index c11daff54..6537f49cf 100644
--- a/src/core/hle/service/ldn/ldn.cpp
+++ b/src/core/hle/service/ldn/ldn.cpp
@@ -4,11 +4,13 @@
 #include <memory>
 
 #include "core/core.h"
+#include "core/hle/service/ldn/lan_discovery.h"
 #include "core/hle/service/ldn/ldn.h"
 #include "core/hle/service/ldn/ldn_results.h"
 #include "core/hle/service/ldn/ldn_types.h"
 #include "core/internal_network/network.h"
 #include "core/internal_network/network_interface.h"
+#include "network/network.h"
 
 // This is defined by synchapi.h and conflicts with ServiceContext::CreateEvent
 #undef CreateEvent
@@ -105,13 +107,13 @@ class IUserLocalCommunicationService final
 public:
     explicit IUserLocalCommunicationService(Core::System& system_)
         : ServiceFramework{system_, "IUserLocalCommunicationService", ServiceThreadType::CreateNew},
-          service_context{system, "IUserLocalCommunicationService"}, room_network{
-                                                                         system_.GetRoomNetwork()} {
+          service_context{system, "IUserLocalCommunicationService"},
+          room_network{system_.GetRoomNetwork()}, lan_discovery{room_network} {
         // clang-format off
         static const FunctionInfo functions[] = {
             {0, &IUserLocalCommunicationService::GetState, "GetState"},
             {1, &IUserLocalCommunicationService::GetNetworkInfo, "GetNetworkInfo"},
-            {2, nullptr, "GetIpv4Address"},
+            {2, &IUserLocalCommunicationService::GetIpv4Address, "GetIpv4Address"},
             {3, &IUserLocalCommunicationService::GetDisconnectReason, "GetDisconnectReason"},
             {4, &IUserLocalCommunicationService::GetSecurityParameter, "GetSecurityParameter"},
             {5, &IUserLocalCommunicationService::GetNetworkConfig, "GetNetworkConfig"},
@@ -119,7 +121,7 @@ public:
             {101, &IUserLocalCommunicationService::GetNetworkInfoLatestUpdate, "GetNetworkInfoLatestUpdate"},
             {102, &IUserLocalCommunicationService::Scan, "Scan"},
             {103, &IUserLocalCommunicationService::ScanPrivate, "ScanPrivate"},
-            {104, nullptr, "SetWirelessControllerRestriction"},
+            {104, &IUserLocalCommunicationService::SetWirelessControllerRestriction, "SetWirelessControllerRestriction"},
             {200, &IUserLocalCommunicationService::OpenAccessPoint, "OpenAccessPoint"},
             {201, &IUserLocalCommunicationService::CloseAccessPoint, "CloseAccessPoint"},
             {202, &IUserLocalCommunicationService::CreateNetwork, "CreateNetwork"},
@@ -148,16 +150,30 @@ public:
     }
 
     ~IUserLocalCommunicationService() {
+        if (is_initialized) {
+            if (auto room_member = room_network.GetRoomMember().lock()) {
+                room_member->Unbind(ldn_packet_received);
+            }
+        }
+
         service_context.CloseEvent(state_change_event);
     }
 
+    /// Callback to parse and handle a received LDN packet.
+    void OnLDNPacketReceived(const Network::LDNPacket& packet) {
+        lan_discovery.ReceivePacket(packet);
+    }
+
     void OnEventFired() {
         state_change_event->GetWritableEvent().Signal();
     }
 
     void GetState(Kernel::HLERequestContext& ctx) {
         State state = State::Error;
-        LOG_WARNING(Service_LDN, "(STUBBED) called, state = {}", state);
+
+        if (is_initialized) {
+            state = lan_discovery.GetState();
+        }
 
         IPC::ResponseBuilder rb{ctx, 3};
         rb.Push(ResultSuccess);
@@ -175,7 +191,7 @@ public:
         }
 
         NetworkInfo network_info{};
-        const auto rc = ResultSuccess;
+        const auto rc = lan_discovery.GetNetworkInfo(network_info);
         if (rc.IsError()) {
             LOG_ERROR(Service_LDN, "NetworkInfo is not valid {}", rc.raw);
             IPC::ResponseBuilder rb{ctx, 2};
@@ -183,28 +199,52 @@ public:
             return;
         }
 
-        LOG_WARNING(Service_LDN, "(STUBBED) called, ssid='{}', nodes={}",
-                    network_info.common.ssid.GetStringValue(), network_info.ldn.node_count);
-
         ctx.WriteBuffer<NetworkInfo>(network_info);
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(rc);
+        rb.Push(ResultSuccess);
     }
 
-    void GetDisconnectReason(Kernel::HLERequestContext& ctx) {
-        const auto disconnect_reason = DisconnectReason::None;
+    void GetIpv4Address(Kernel::HLERequestContext& ctx) {
+        LOG_CRITICAL(Service_LDN, "called");
 
-        LOG_WARNING(Service_LDN, "(STUBBED) called, disconnect_reason={}", disconnect_reason);
+        const auto network_interface = Network::GetSelectedNetworkInterface();
+
+        if (!network_interface) {
+            LOG_ERROR(Service_LDN, "No network interface available");
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ResultNoIpAddress);
+            return;
+        }
+
+        Ipv4Address current_address{Network::TranslateIPv4(network_interface->ip_address)};
+        Ipv4Address subnet_mask{Network::TranslateIPv4(network_interface->subnet_mask)};
+
+        // When we're connected to a room, spoof the hosts IP address
+        if (auto room_member = room_network.GetRoomMember().lock()) {
+            if (room_member->IsConnected()) {
+                current_address = room_member->GetFakeIpAddress();
+            }
+        }
+
+        std::reverse(std::begin(current_address), std::end(current_address)); // ntohl
+        std::reverse(std::begin(subnet_mask), std::end(subnet_mask));         // ntohl
+
+        IPC::ResponseBuilder rb{ctx, 4};
+        rb.Push(ResultSuccess);
+        rb.PushRaw(current_address);
+        rb.PushRaw(subnet_mask);
+    }
 
+    void GetDisconnectReason(Kernel::HLERequestContext& ctx) {
         IPC::ResponseBuilder rb{ctx, 3};
         rb.Push(ResultSuccess);
-        rb.PushEnum(disconnect_reason);
+        rb.PushEnum(lan_discovery.GetDisconnectReason());
     }
 
     void GetSecurityParameter(Kernel::HLERequestContext& ctx) {
         SecurityParameter security_parameter{};
         NetworkInfo info{};
-        const Result rc = ResultSuccess;
+        const Result rc = lan_discovery.GetNetworkInfo(info);
 
         if (rc.IsError()) {
             LOG_ERROR(Service_LDN, "NetworkInfo is not valid {}", rc.raw);
@@ -217,8 +257,6 @@ public:
         std::memcpy(security_parameter.data.data(), info.ldn.security_parameter.data(),
                     sizeof(SecurityParameter::data));
 
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
-
         IPC::ResponseBuilder rb{ctx, 10};
         rb.Push(rc);
         rb.PushRaw<SecurityParameter>(security_parameter);
@@ -227,7 +265,7 @@ public:
     void GetNetworkConfig(Kernel::HLERequestContext& ctx) {
         NetworkConfig config{};
         NetworkInfo info{};
-        const Result rc = ResultSuccess;
+        const Result rc = lan_discovery.GetNetworkInfo(info);
 
         if (rc.IsError()) {
             LOG_ERROR(Service_LDN, "NetworkConfig is not valid {}", rc.raw);
@@ -241,12 +279,6 @@ public:
         config.node_count_max = info.ldn.node_count_max;
         config.local_communication_version = info.ldn.nodes[0].local_communication_version;
 
-        LOG_WARNING(Service_LDN,
-                    "(STUBBED) called, intent_id={}/{}, channel={}, node_count_max={}, "
-                    "local_communication_version={}",
-                    config.intent_id.local_communication_id, config.intent_id.scene_id,
-                    config.channel, config.node_count_max, config.local_communication_version);
-
         IPC::ResponseBuilder rb{ctx, 10};
         rb.Push(rc);
         rb.PushRaw<NetworkConfig>(config);
@@ -265,17 +297,17 @@ public:
         const std::size_t node_buffer_count = ctx.GetWriteBufferSize(1) / sizeof(NodeLatestUpdate);
 
         if (node_buffer_count == 0 || network_buffer_size != sizeof(NetworkInfo)) {
-            LOG_ERROR(Service_LDN, "Invalid buffer size {}, {}", network_buffer_size,
+            LOG_ERROR(Service_LDN, "Invalid buffer, size = {}, count = {}", network_buffer_size,
                       node_buffer_count);
             IPC::ResponseBuilder rb{ctx, 2};
             rb.Push(ResultBadInput);
             return;
         }
 
-        NetworkInfo info;
+        NetworkInfo info{};
         std::vector<NodeLatestUpdate> latest_update(node_buffer_count);
 
-        const auto rc = ResultSuccess;
+        const auto rc = lan_discovery.GetNetworkInfo(info, latest_update, latest_update.size());
         if (rc.IsError()) {
             LOG_ERROR(Service_LDN, "NetworkInfo is not valid {}", rc.raw);
             IPC::ResponseBuilder rb{ctx, 2};
@@ -283,9 +315,6 @@ public:
             return;
         }
 
-        LOG_WARNING(Service_LDN, "(STUBBED) called, ssid='{}', nodes={}",
-                    info.common.ssid.GetStringValue(), info.ldn.node_count);
-
         ctx.WriteBuffer(info, 0);
         ctx.WriteBuffer(latest_update, 1);
 
@@ -317,92 +346,78 @@ public:
 
         u16 count = 0;
         std::vector<NetworkInfo> network_infos(network_info_size);
+        Result rc = lan_discovery.Scan(network_infos, count, scan_filter);
 
-        LOG_WARNING(Service_LDN,
-                    "(STUBBED) called, channel={}, filter_scan_flag={}, filter_network_type={}",
-                    channel, scan_filter.flag, scan_filter.network_type);
+        LOG_INFO(Service_LDN,
+                 "called, channel={}, filter_scan_flag={}, filter_network_type={}, is_private={}",
+                 channel, scan_filter.flag, scan_filter.network_type, is_private);
 
         ctx.WriteBuffer(network_infos);
 
         IPC::ResponseBuilder rb{ctx, 3};
-        rb.Push(ResultSuccess);
+        rb.Push(rc);
         rb.Push<u32>(count);
     }
 
-    void OpenAccessPoint(Kernel::HLERequestContext& ctx) {
+    void SetWirelessControllerRestriction(Kernel::HLERequestContext& ctx) {
         LOG_WARNING(Service_LDN, "(STUBBED) called");
 
         IPC::ResponseBuilder rb{ctx, 2};
         rb.Push(ResultSuccess);
     }
 
+    void OpenAccessPoint(Kernel::HLERequestContext& ctx) {
+        LOG_INFO(Service_LDN, "called");
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        rb.Push(lan_discovery.OpenAccessPoint());
+    }
+
     void CloseAccessPoint(Kernel::HLERequestContext& ctx) {
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
+        LOG_INFO(Service_LDN, "called");
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.CloseAccessPoint());
     }
 
     void CreateNetwork(Kernel::HLERequestContext& ctx) {
-        IPC::RequestParser rp{ctx};
-        struct Parameters {
-            SecurityConfig security_config;
-            UserConfig user_config;
-            INSERT_PADDING_WORDS_NOINIT(1);
-            NetworkConfig network_config;
-        };
-        static_assert(sizeof(Parameters) == 0x98, "Parameters has incorrect size.");
+        LOG_INFO(Service_LDN, "called");
 
-        const auto parameters{rp.PopRaw<Parameters>()};
+        CreateNetworkImpl(ctx);
+    }
 
-        LOG_WARNING(Service_LDN,
-                    "(STUBBED) called, passphrase_size={}, security_mode={}, "
-                    "local_communication_version={}",
-                    parameters.security_config.passphrase_size,
-                    parameters.security_config.security_mode,
-                    parameters.network_config.local_communication_version);
+    void CreateNetworkPrivate(Kernel::HLERequestContext& ctx) {
+        LOG_INFO(Service_LDN, "called");
 
-        IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        CreateNetworkImpl(ctx, true);
     }
 
-    void CreateNetworkPrivate(Kernel::HLERequestContext& ctx) {
+    void CreateNetworkImpl(Kernel::HLERequestContext& ctx, bool is_private = false) {
         IPC::RequestParser rp{ctx};
-        struct Parameters {
-            SecurityConfig security_config;
-            SecurityParameter security_parameter;
-            UserConfig user_config;
-            NetworkConfig network_config;
-        };
-        static_assert(sizeof(Parameters) == 0xB8, "Parameters has incorrect size.");
-
-        const auto parameters{rp.PopRaw<Parameters>()};
 
-        LOG_WARNING(Service_LDN,
-                    "(STUBBED) called, passphrase_size={}, security_mode={}, "
-                    "local_communication_version={}",
-                    parameters.security_config.passphrase_size,
-                    parameters.security_config.security_mode,
-                    parameters.network_config.local_communication_version);
+        const auto security_config{rp.PopRaw<SecurityConfig>()};
+        [[maybe_unused]] const auto security_parameter{is_private ? rp.PopRaw<SecurityParameter>()
+                                                                  : SecurityParameter{}};
+        const auto user_config{rp.PopRaw<UserConfig>()};
+        rp.Pop<u32>(); // Padding
+        const auto network_Config{rp.PopRaw<NetworkConfig>()};
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.CreateNetwork(security_config, user_config, network_Config));
     }
 
     void DestroyNetwork(Kernel::HLERequestContext& ctx) {
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
+        LOG_INFO(Service_LDN, "called");
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.DestroyNetwork());
     }
 
     void SetAdvertiseData(Kernel::HLERequestContext& ctx) {
         std::vector<u8> read_buffer = ctx.ReadBuffer();
 
-        LOG_WARNING(Service_LDN, "(STUBBED) called, size {}", read_buffer.size());
-
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.SetAdvertiseData(read_buffer));
     }
 
     void SetStationAcceptPolicy(Kernel::HLERequestContext& ctx) {
@@ -420,17 +435,17 @@ public:
     }
 
     void OpenStation(Kernel::HLERequestContext& ctx) {
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
+        LOG_INFO(Service_LDN, "called");
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.OpenStation());
     }
 
     void CloseStation(Kernel::HLERequestContext& ctx) {
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
+        LOG_INFO(Service_LDN, "called");
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.CloseStation());
     }
 
     void Connect(Kernel::HLERequestContext& ctx) {
@@ -445,16 +460,13 @@ public:
 
         const auto parameters{rp.PopRaw<Parameters>()};
 
-        LOG_WARNING(Service_LDN,
-                    "(STUBBED) called, passphrase_size={}, security_mode={}, "
-                    "local_communication_version={}",
-                    parameters.security_config.passphrase_size,
-                    parameters.security_config.security_mode,
-                    parameters.local_communication_version);
+        LOG_INFO(Service_LDN,
+                 "called, passphrase_size={}, security_mode={}, "
+                 "local_communication_version={}",
+                 parameters.security_config.passphrase_size,
+                 parameters.security_config.security_mode, parameters.local_communication_version);
 
         const std::vector<u8> read_buffer = ctx.ReadBuffer();
-        NetworkInfo network_info{};
-
         if (read_buffer.size() != sizeof(NetworkInfo)) {
             LOG_ERROR(Frontend, "NetworkInfo doesn't match read_buffer size!");
             IPC::ResponseBuilder rb{ctx, 2};
@@ -462,40 +474,47 @@ public:
             return;
         }
 
+        NetworkInfo network_info{};
         std::memcpy(&network_info, read_buffer.data(), read_buffer.size());
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.Connect(network_info, parameters.user_config,
+                                      static_cast<u16>(parameters.local_communication_version)));
     }
 
     void Disconnect(Kernel::HLERequestContext& ctx) {
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
+        LOG_INFO(Service_LDN, "called");
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.Disconnect());
     }
-    void Initialize(Kernel::HLERequestContext& ctx) {
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
 
+    void Initialize(Kernel::HLERequestContext& ctx) {
         const auto rc = InitializeImpl(ctx);
+        if (rc.IsError()) {
+            LOG_ERROR(Service_LDN, "Network isn't initialized, rc={}", rc.raw);
+        }
 
         IPC::ResponseBuilder rb{ctx, 2};
         rb.Push(rc);
     }
 
     void Finalize(Kernel::HLERequestContext& ctx) {
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
+        if (auto room_member = room_network.GetRoomMember().lock()) {
+            room_member->Unbind(ldn_packet_received);
+        }
 
         is_initialized = false;
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
+        rb.Push(lan_discovery.Finalize());
     }
 
     void Initialize2(Kernel::HLERequestContext& ctx) {
-        LOG_WARNING(Service_LDN, "(STUBBED) called");
-
         const auto rc = InitializeImpl(ctx);
+        if (rc.IsError()) {
+            LOG_ERROR(Service_LDN, "Network isn't initialized, rc={}", rc.raw);
+        }
 
         IPC::ResponseBuilder rb{ctx, 2};
         rb.Push(rc);
@@ -508,14 +527,26 @@ public:
             return ResultAirplaneModeEnabled;
         }
 
+        if (auto room_member = room_network.GetRoomMember().lock()) {
+            ldn_packet_received = room_member->BindOnLdnPacketReceived(
+                [this](const Network::LDNPacket& packet) { OnLDNPacketReceived(packet); });
+        } else {
+            LOG_ERROR(Service_LDN, "Couldn't bind callback!");
+            return ResultAirplaneModeEnabled;
+        }
+
+        lan_discovery.Initialize([&]() { OnEventFired(); });
         is_initialized = true;
-        // TODO (flTobi): Change this to ResultSuccess when LDN is fully implemented
-        return ResultAirplaneModeEnabled;
+        return ResultSuccess;
     }
 
     KernelHelpers::ServiceContext service_context;
     Kernel::KEvent* state_change_event;
     Network::RoomNetwork& room_network;
+    LANDiscovery lan_discovery;
+
+    // Callback identifier for the OnLDNPacketReceived event.
+    Network::RoomMember::CallbackHandle<Network::LDNPacket> ldn_packet_received;
 
     bool is_initialized{};
 };
diff --git a/src/core/hle/service/ldn/ldn_types.h b/src/core/hle/service/ldn/ldn_types.h
index 6231e936d..d6609fff5 100644
--- a/src/core/hle/service/ldn/ldn_types.h
+++ b/src/core/hle/service/ldn/ldn_types.h
@@ -31,6 +31,14 @@ enum class NodeStateChange : u8 {
     DisconnectAndConnect,
 };
 
+inline NodeStateChange operator|(NodeStateChange a, NodeStateChange b) {
+    return static_cast<NodeStateChange>(static_cast<u8>(a) | static_cast<u8>(b));
+}
+
+inline NodeStateChange operator|=(NodeStateChange& a, NodeStateChange b) {
+    return a = a | b;
+}
+
 enum class ScanFilterFlag : u32 {
     None = 0,
     LocalCommunicationId = 1 << 0,
@@ -100,13 +108,13 @@ enum class AcceptPolicy : u8 {
 
 enum class WifiChannel : s16 {
     Default = 0,
-    wifi24_1 = 1,
-    wifi24_6 = 6,
-    wifi24_11 = 11,
-    wifi50_36 = 36,
-    wifi50_40 = 40,
-    wifi50_44 = 44,
-    wifi50_48 = 48,
+    Wifi24_1 = 1,
+    Wifi24_6 = 6,
+    Wifi24_11 = 11,
+    Wifi50_36 = 36,
+    Wifi50_40 = 40,
+    Wifi50_44 = 44,
+    Wifi50_48 = 48,
 };
 
 enum class LinkLevel : s8 {
@@ -116,6 +124,11 @@ enum class LinkLevel : s8 {
     Excellent,
 };
 
+enum class NodeStatus : u8 {
+    Disconnected,
+    Connected,
+};
+
 struct NodeLatestUpdate {
     NodeStateChange state_change;
     INSERT_PADDING_BYTES(0x7); // Unknown
@@ -159,19 +172,14 @@ struct Ssid {
     std::string GetStringValue() const {
         return std::string(raw.data());
     }
-};
-static_assert(sizeof(Ssid) == 0x22, "Ssid is an invalid size");
-
-struct Ipv4Address {
-    union {
-        u32 raw{};
-        std::array<u8, 4> bytes;
-    };
 
-    std::string GetStringValue() const {
-        return fmt::format("{}.{}.{}.{}", bytes[3], bytes[2], bytes[1], bytes[0]);
+    bool operator==(const Ssid& b) const {
+        return (length == b.length) && (std::memcmp(raw.data(), b.raw.data(), length) == 0);
     }
 };
+static_assert(sizeof(Ssid) == 0x22, "Ssid is an invalid size");
+
+using Ipv4Address = std::array<u8, 4>;
 static_assert(sizeof(Ipv4Address) == 0x4, "Ipv4Address is an invalid size");
 
 struct MacAddress {
@@ -181,6 +189,14 @@ struct MacAddress {
 };
 static_assert(sizeof(MacAddress) == 0x6, "MacAddress is an invalid size");
 
+struct MACAddressHash {
+    size_t operator()(const MacAddress& address) const {
+        u64 value{};
+        std::memcpy(&value, address.raw.data(), sizeof(address.raw));
+        return value;
+    }
+};
+
 struct ScanFilter {
     NetworkId network_id;
     NetworkType network_type;