clientiface.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2010-2014 celeron55, Perttu Ahola <celeron55@gmail.com>
 
#pragma once
 
#include "irr_v3d.h"                   // for irrlicht datatypes
 
#include "network/address.h"
#include "network/networkprotocol.h" // session_t
#include "threading/mutex_auto_lock.h"
#include "clientdynamicinfo.h"
#include "constants.h" // PEER_ID_INEXISTENT
 
#include <memory>
#include <mutex>
#include <set>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
 
class EmergeManager;
class MapBlock;
class NetworkPacket;
struct PointedThing;
class ServerEnvironment;
 
/*
 * State Transitions
 
      Start
  (peer connect)
        |
        v
      /-----------------\
      |                 |
      |    Created      |
      |                 |
      \-----------------/
               |                  depending on the incoming packet
               ----------------------------------------
                                                      v
                                       +-----------------------------+
                                       |IN:                          |
                                       | TOSERVER_INIT               |
                                       +-----------------------------+
                                                      | invalid playername
                                                      | or denied by mod
                                                      v
                                       +-----------------------------+
                                       |OUT:                         |
                                       | TOCLIENT_HELLO              |
                                       +-----------------------------+
                                                      |
                                                      |
                                                      v
      /-----------------\                    /-----------------\
      |                 |                    |                 |
      |  AwaitingInit2  |<---------          |    HelloSent    |
      |                 |         |          |                 |
      \-----------------/         |          \-----------------/
               |                  |                   |
+-----------------------------+   |    *-----------------------------*     Auth fails
|IN:                          |   |    |Authentication, depending on |------------------
| TOSERVER_INIT2              |   |    | packet sent by client       |                 |
+-----------------------------+   |    *-----------------------------*                 |
               |                  |                   |                                |
               |                  |                   | Authentication                 |
               v                  |                   |  successful                    |
      /-----------------\         |                   v                                |
      |                 |         |    +-----------------------------+                 |
      |    InitDone     |         |    |OUT:                         |                 |
      |                 |         |    | TOCLIENT_AUTH_ACCEPT        |                 |
      \-----------------/         |    +-----------------------------+                 |
               |                  |                   |                                |
+-----------------------------+   ---------------------                                |
|OUT:                         |                                                        |
| TOCLIENT_MOVEMENT           |                                                        |
| TOCLIENT_ITEMDEF            |                                                        |
| TOCLIENT_NODEDEF            |                                                        |
| TOCLIENT_ANNOUNCE_MEDIA     |                                                        |
| TOCLIENT_DETACHED_INVENTORY |                                                        |
| TOCLIENT_TIME_OF_DAY        |                                                        |
+-----------------------------+                                                        |
               |                                                                       |
               |                                                                       |
               |      -----------------------------                                    |
               v      |                           |                                    |
      /-----------------\                         v                                    |
      |                 |             +-----------------------------+                  |
      | DefinitionsSent |             |IN:                          |                  |
      |                 |             | TOSERVER_REQUEST_MEDIA      |                  |
      \-----------------/             |                             |                  |
               |                      +-----------------------------+                  |
               |      ^                           |                                    |
               |      -----------------------------                                    |
               v                                                                       v
+-----------------------------+                        --------------------------------+
|IN:                          |                        |                               ^
| TOSERVER_CLIENT_READY       |                        v                               |
+-----------------------------+            +------------------------+                  |
               |                           |OUT:                    |                  |
               v                           | TOCLIENT_ACCESS_DENIED |                  |
+-----------------------------+            +------------------------+                  |
|OUT:                         |                        |                               |
| TOCLIENT_MOVE_PLAYER        |                        v                               |
| TOCLIENT_PRIVILEGES         |                /-----------------\                     |
| TOCLIENT_INVENTORY_FORMSPEC |                |                 |                     |
| UpdateCrafting              |                |     Denied      |                     |
| TOCLIENT_INVENTORY          |                |                 |                     |
| TOCLIENT_HP (opt)           |                \-----------------/                     |
| TOCLIENT_BREATH             |                                                        |
| TOCLIENT_DEATHSCREEN_LEGACY |                                                        |
+-----------------------------+                                                        |
              |                                                                        |
              v                                                                        |
      /-----------------\      async mod action (ban, kick)                            |
      |                 |---------------------------------------------------------------
 ---->|     Active      |
 |    |                 |----------------------------------------------
 |    \-----------------/      timeout                                v
 |       |           |                                  +-----------------------------+
 |       |           |                                  |OUT:                         |
 |       |           |                                  | TOCLIENT_DISCONNECT         |
 |       |           |                                  +-----------------------------+
 |       |           |                                                |
 |       |           v                                                v
 |       |  +-----------------------------+                    /-----------------\
 |       |  |IN:                          |                    |                 |
 |       |  | TOSERVER_DISCONNECT         |------------------->|  Disconnecting  |
 |       |  +-----------------------------+                    |                 |
 |       |                                                     \-----------------/
 |       | any auth packet which was
 |       | allowed in TOCLIENT_AUTH_ACCEPT
 |       v
 |    *-----------------------------* Auth      +-------------------------------+
 |    |Authentication, depending on | succeeds  |OUT:                           |
 |    | packet sent by client       |---------->| TOCLIENT_ACCEPT_SUDO_MODE     |
 |    *-----------------------------*           +-------------------------------+
 |                  |                                            |
 |                  | Auth fails                        /-----------------\
 |                  v                                   |                 |
 |    +-------------------------------+                 |    SudoMode     |
 |    |OUT:                           |                 |                 |
 |    | TOCLIENT_DENY_SUDO_MODE       |                 \-----------------/
 |    +-------------------------------+                          |
 |                  |                                            v
 |                  |                               +-----------------------------+
 |                  |    sets password accordingly  |IN:                          |
 -------------------+-------------------------------| TOSERVER_FIRST_SRP          |
                                                    +-----------------------------+
 
*/
namespace con {
        class IConnection;
}
 
 
// Also make sure to update the ClientInterface::statenames
// array when modifying these enums
 
enum ClientState
{
        CS_Invalid,
        CS_Disconnecting,
        CS_Denied,
        CS_Created,
        CS_HelloSent,
        CS_AwaitingInit2,
        CS_InitDone,
        CS_DefinitionsSent,
        CS_Active,
        CS_SudoMode
};
 
enum ClientStateEvent
{
        CSE_Hello,
        CSE_AuthAccept,
        CSE_GotInit2,
        CSE_SetDenied,
        CSE_SetDefinitionsSent,
        CSE_SetClientReady,
        CSE_SudoSuccess,
        CSE_SudoLeave,
        CSE_Disconnect
};
 
/*
        Used for queueing and sorting block transfers in containers
 
        Lower priority number means higher priority.
*/
struct PrioritySortedBlockTransfer
{
        PrioritySortedBlockTransfer(float a_priority, const v3s16 &a_pos, session_t a_peer_id)
        {
                priority = a_priority;
                pos = a_pos;
                peer_id = a_peer_id;
        }
        bool operator < (const PrioritySortedBlockTransfer &other) const
        {
                return priority < other.priority;
        }
        float priority;
        v3s16 pos;
        session_t peer_id;
};
 
class RemoteClient
{
public:
        // peer_id=0 means this client has no associated peer
        // NOTE: If client is made allowed to exist while peer doesn't,
        //       this has to be set to 0 when there is no peer.
        //       Also, the client must be moved to some other container.
        session_t peer_id = PEER_ID_INEXISTENT;
        // The serialization version to use with the client
        u8 serialization_version;
        //
        u16 net_proto_version = 0;
 
        /* Authentication information */
        std::string enc_pwd = "";
        bool create_player_on_auth_success = false;
        AuthMechanism chosen_mech  = AUTH_MECHANISM_NONE;
        void *auth_data = nullptr;
        u32 allowed_auth_mechs = 0;
 
        void resetChosenMech();
 
        bool isMechAllowed(AuthMechanism mech)
        { return allowed_auth_mechs & mech; }
 
        void setEncryptedPassword(const std::string& pwd);
 
        RemoteClient();
        ~RemoteClient() = default;
 
        /*
                Finds block that should be sent next to the client.
                Environment should be locked when this is called.
                dtime is used for resetting send radius at slow interval
        */
        void GetNextBlocks(ServerEnvironment *env, EmergeManager* emerge,
                        float dtime, std::vector<PrioritySortedBlockTransfer> &dest);
 
        void GotBlock(v3s16 p);
 
        void SentBlock(v3s16 p);
 
        void SetBlockNotSent(v3s16 p, bool low_priority = false);
        void SetBlocksNotSent(const std::vector<v3s16> &blocks, bool low_priority = false);

        void fixupNodePrediction(InteractAction action,
                const PointedThing &pointed, bool prediction_success);
 
        u32 getSendingCount() const { return m_blocks_sending.size(); }
 
        bool isBlockSent(v3s16 p) const
        {
                return m_blocks_sent.find(p) != m_blocks_sent.end();
        }
 
        bool markMediaSent(const std::string &name) {
                auto insert_result = m_media_sent.emplace(name);
                return insert_result.second; // true = was inserted
        }
 
        void PrintInfo(std::ostream &o)
        {
                o << "RemoteClient " << peer_id << ": "
                        <<"blocks_sent=" << m_blocks_sent.size()
                        <<", blocks_sending=" << m_blocks_sending.size()
                        <<", nearest_unsent_d=" << m_nearest_unsent_d
                        <<", map_send_completion_timer=" << (int)(m_map_send_completion_timer + 0.5f)
                        <<", excess_gotblocks=" << m_excess_gotblocks;
                m_excess_gotblocks = 0;
        }
 
        // Time from last placing or removing blocks
        float m_time_from_building = 9999;
 
        /*
                List of active objects that the client knows of.
        */
        std::set<u16> m_known_objects;
 
        ClientState getState() const { return m_state; }
 
        const std::string &getName() const { return m_name; }
 
        void setName(const std::string &name) { m_name = name; }
 
        /* update internal client state */
        void notifyEvent(ClientStateEvent event);
 
        /* set expected serialization version */
        void setPendingSerializationVersion(u8 version)
                { m_pending_serialization_version = version; }
 
        void confirmSerializationVersion()
                { serialization_version = m_pending_serialization_version; }
 
        /* get uptime */
        u64 uptime() const;
 
        /* set version information */
        void setVersionInfo(u8 major, u8 minor, u8 patch, const std::string &full);
 
        /* read version information */
        u8 getMajor() const { return m_version_major; }
        u8 getMinor() const { return m_version_minor; }
        u8 getPatch() const { return m_version_patch; }
        const std::string &getFullVer() const { return m_full_version; }
 
        void setLangCode(const std::string &code);
        const std::string &getLangCode() const { return m_lang_code; }
 
        void setCachedAddress(const Address &addr) { m_addr = addr; }
        const Address &getAddress() const { return m_addr; }
 
        void setDynamicInfo(const ClientDynamicInfo &info) { m_dynamic_info = info; }
        const ClientDynamicInfo &getDynamicInfo() const { return m_dynamic_info; }
 
private:
        // Version is stored in here after INIT before INIT2
        u8 m_pending_serialization_version;
 
        /* current state of client */
        ClientState m_state = CS_Created;
 
        // Cached here so retrieval doesn't have to go to connection API
        Address m_addr;
 
        // Client-sent language code
        std::string m_lang_code;
 
        // Client-sent dynamic info
        ClientDynamicInfo m_dynamic_info{};
 
        /*
                Blocks that have been sent to client.
                - These don't have to be sent again.
                - A block is cleared from here when client says it has
                  deleted it from it's memory
 
                List of block positions.
                No MapBlock* is stored here because the blocks can get deleted.
        */
        std::unordered_set<v3s16> m_blocks_sent;
 
        /*
                Cache of blocks that have been occlusion culled at the current distance.
                As GetNextBlocks traverses the same distance multiple times, this saves
                significant CPU time.
         */
        std::unordered_set<v3s16> m_blocks_occ;
 
        s16 m_nearest_unsent_d = 0;
        v3s16 m_last_center;
        v3f m_last_camera_dir;
 
        const u16 m_max_simul_sends;
        const float m_min_time_from_building;
        const s16 m_max_send_distance;
        const s16 m_block_optimize_distance;
        const s16 m_block_cull_optimize_distance;
        const s16 m_max_gen_distance;
        const bool m_occ_cull;
 
        /*
                Set of media files the client has already requested
                We won't send the same file twice to avoid bandwidth consumption attacks.
        */
        std::unordered_set<std::string> m_media_sent;
 
        /*
                Blocks that are currently on the line.
                This is used for throttling the sending of blocks.
                - The size of this list is limited to some value
                Block is added when it is sent with BLOCKDATA.
                Block is removed when GOTBLOCKS is received.
        */
        std::unordered_set<v3s16> m_blocks_sending;
 
        /*
                Count of excess GotBlocks().
                There is an excess amount because the client sometimes
                gets a block so late that the server sends it again,
                and the client then sends two GOTBLOCKs.
                This is reset by PrintInfo()
        */
        u32 m_excess_gotblocks = 0;
 
        // CPU usage optimization
        float m_nothing_to_send_pause_timer = 0.0f;
 
        // measure how long it takes the server to send the complete map
        float m_map_send_completion_timer = 0.0f;
 
        /*
                name of player using this client
        */
        std::string m_name = "";
 
        /*
                client information
        */
        u8 m_version_major = 0;
        u8 m_version_minor = 0;
        u8 m_version_patch = 0;
 
        std::string m_full_version = "unknown";
 
        /*
                time this client was created
         */
        const u64 m_connection_time;
};
 
typedef std::unordered_map<u16, RemoteClient*> RemoteClientMap;
 
class ClientInterface {
public:
 
        friend class Server;
 
        ClientInterface(const std::shared_ptr<con::IConnection> &con);
        ~ClientInterface();
 
        /* run sync step */
        void step(float dtime);
 
        /* get list of active client id's */
        std::vector<session_t> getClientIDs(ClientState min_state=CS_Active);
 
        /* mark blocks as not sent on all active clients */
        void markBlocksNotSent(const std::vector<v3s16> &positions, bool low_priority = false);
 
        /* verify if server user limit was reached */
        bool isUserLimitReached();
 
        /* get list of client player names */
        const std::vector<std::string> &getPlayerNames() const { return m_clients_names; }
 
        /* send to one client */
        void send(session_t peer_id, NetworkPacket *pkt);
 
        /* send to one client, deviating from the standard params */
        void sendCustom(session_t peer_id, u8 channel, NetworkPacket *pkt, bool reliable);
 
        /* send to all clients */
        void sendToAll(NetworkPacket *pkt, ClientState state_min = CS_Active);
 
        /* delete a client */
        void DeleteClient(session_t peer_id);
 
        /* create client */
        void CreateClient(session_t peer_id);
 
        /* get a client by peer_id */
        RemoteClient *getClientNoEx(session_t peer_id,  ClientState state_min = CS_Active);
 
        /* get client by peer_id (make sure you have list lock before!*/
        RemoteClient *lockedGetClientNoEx(session_t peer_id,  ClientState state_min = CS_Active);
 
        /* get state of client by id*/
        ClientState getClientState(session_t peer_id);
 
        /* get protocol version of client */
        u16 getProtocolVersion(session_t peer_id);
 
        /* event to update client state */
        void event(session_t peer_id, ClientStateEvent event);
 
        /* Set environment. Do not call this function if environment is already set */
        void setEnv(ServerEnvironment *env)
        {
                assert(m_env == NULL); // pre-condition
                m_env = env;
        }
 
        static const char *state2Name(ClientState state);
 
protected:
        class AutoLock {
        public:
                AutoLock(ClientInterface &iface): m_lock(iface.m_clients_mutex) {}
 
        private:
                RecursiveMutexAutoLock m_lock;
        };
 
        RemoteClientMap& getClientList() { return m_clients; }
 
private:
        /* update internal player list */
        void UpdatePlayerList();
 
        // Connection
        std::shared_ptr<con::IConnection> m_con;
 
        // FIXME?: as far as I can tell this lock is pointless because only the server
        // thread ever touches the clients. Consider how getClientNoEx() returns
        // a raw pointer too.
        std::recursive_mutex m_clients_mutex;
        // Connected clients (behind the mutex)
        RemoteClientMap m_clients;
        std::vector<std::string> m_clients_names; // for announcing to server list
 
        // Environment
        ServerEnvironment *m_env = nullptr;
 
        float m_print_info_timer = 0;
        float m_check_linger_timer = 0;
 
        static const char *statenames[];
 
        // Note that this puts a fixed timeout on the init & auth phase for a client.
        // (lingering is enforced until CS_InitDone)
        static constexpr int LINGER_TIMEOUT = 12;
};