threads.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2013-2017 celeron55, Perttu Ahola <celeron55@gmail.com>
// Copyright (C) 2017 celeron55, Loic Blot <loic.blot@unix-experience.fr>
 
#pragma once
 
/********************************************/
/* may only be included from in src/network */
/********************************************/
 
#include <cassert>
#include "threading/thread.h"
#include "network/mtp/internal.h"
 
namespace con
{
 
class Connection;
 
struct OutgoingPacket
{
        session_t peer_id;
        u8 channelnum;
        SharedBuffer<u8> data;
        bool reliable;
        bool ack;
 
        OutgoingPacket(session_t peer_id_, u8 channelnum_, const SharedBuffer<u8> &data_,
                        bool reliable_,bool ack_=false):
                peer_id(peer_id_),
                channelnum(channelnum_),
                data(data_),
                reliable(reliable_),
                ack(ack_)
        {
        }
};
 
class ConnectionSendThread : public Thread
{
 
public:
        friend class UDPPeer;
 
        ConnectionSendThread(unsigned int max_packet_size, float timeout);
 
        void *run();
 
        void Trigger();
 
        void setParent(Connection *parent)
        {
                assert(parent != NULL); // Pre-condition
                m_connection = parent;
        }
 
        void setPeerTimeout(float peer_timeout) { m_timeout = peer_timeout; }
 
private:
        void runTimeouts(float dtime, u32 peer_packet_quota);
        void resendReliable(Channel &channel, const BufferedPacket *k, float resend_timeout);
        void rawSend(const BufferedPacket *p);
        bool rawSendAsPacket(session_t peer_id, u8 channelnum,
                        const SharedBuffer<u8> &data, bool reliable);
 
        void processReliableCommand(ConnectionCommandPtr &c);
        void processNonReliableCommand(ConnectionCommandPtr &c);
        void serve(Address bind_address);
        void connect(Address address);
        void disconnect();
        void disconnect_peer(session_t peer_id);
        void fix_peer_id(session_t own_peer_id);
        void send(session_t peer_id, u8 channelnum, const SharedBuffer<u8> &data);
        void sendReliable(ConnectionCommandPtr &c);
        void sendToAll(u8 channelnum, const SharedBuffer<u8> &data);
        void sendToAllReliable(ConnectionCommandPtr &c);
 
        void sendPackets(float dtime, u32 peer_packet_quota);
 
        void sendAsPacket(session_t peer_id, u8 channelnum, const SharedBuffer<u8> &data,
                        bool ack = false);
 
        void sendAsPacketReliable(BufferedPacketPtr &p, Channel *channel);
 
        bool packetsQueued();
 
        Connection *m_connection = nullptr;
        unsigned int m_max_packet_size;
        float m_timeout;
        std::queue<OutgoingPacket> m_outgoing_queue;
        Semaphore m_send_sleep_semaphore;
 
        unsigned int m_iteration_packets_avaialble;
        unsigned int m_max_data_packets_per_iteration;
        unsigned int m_max_packets_requeued = 256;
};
 
class ConnectionReceiveThread : public Thread
{
public:
        ConnectionReceiveThread();
 
        void *run();
 
        void setParent(Connection *parent)
        {
                assert(parent); // Pre-condition
                m_connection = parent;
        }
 
private:
        void receive(SharedBuffer<u8> &packetdata, bool &packet_queued);
 
        // Returns next data from a buffer if possible
        // If found, returns true; if not, false.
        // If found, sets peer_id and dst
        bool getFromBuffers(session_t &peer_id, SharedBuffer<u8> &dst);
 
        bool checkIncomingBuffers(
                        Channel *channel, session_t &peer_id, SharedBuffer<u8> &dst);
 
        /*
                Processes a packet with the basic header stripped out.
                Parameters:
                        packetdata: Data in packet (with no base headers)
                        peer_id: peer id of the sender of the packet in question
                        channelnum: channel on which the packet was sent
                        reliable: true if recursing into a reliable packet
        */
        SharedBuffer<u8> processPacket(Channel *channel,
                        const SharedBuffer<u8> &packetdata, session_t peer_id,
                        u8 channelnum, bool reliable);
 
        SharedBuffer<u8> handlePacketType_Control(Channel *channel,
                        const SharedBuffer<u8> &packetdata, Peer *peer, u8 channelnum,
                        bool reliable);
        SharedBuffer<u8> handlePacketType_Original(Channel *channel,
                        const SharedBuffer<u8> &packetdata, Peer *peer, u8 channelnum,
                        bool reliable);
        SharedBuffer<u8> handlePacketType_Split(Channel *channel,
                        const SharedBuffer<u8> &packetdata, Peer *peer, u8 channelnum,
                        bool reliable);
        SharedBuffer<u8> handlePacketType_Reliable(Channel *channel,
                        const SharedBuffer<u8> &packetdata, Peer *peer, u8 channelnum,
                        bool reliable);
 
        struct PacketTypeHandler
        {
                SharedBuffer<u8> (ConnectionReceiveThread::*handler)(Channel *channel,
                                const SharedBuffer<u8> &packet, Peer *peer, u8 channelnum,
                                bool reliable);
        };
 
        struct RateLimitHelper {
                u64 time = 0;
                int counter = 0;
                bool logged = false;
 
                void tick() {
                        u64 now = porting::getTimeS();
                        if (time != now) {
                                time = now;
                                counter = 0;
                                logged = false;
                        }
                }
        };
 
        static const PacketTypeHandler packetTypeRouter[PACKET_TYPE_MAX];
 
        Connection *m_connection = nullptr;
 
        RateLimitHelper m_new_peer_ratelimit;
};
}