90d5e5d598
git-svn-id: https://svn.code.sf.net/p/fteqw/code/trunk@1355 fc73d0e0-1445-4013-8a0c-d673dee63da5
412 lines
10 KiB
C
412 lines
10 KiB
C
/*
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Copyright (C) 1996-1997 Id Software, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the included (GNU.txt) GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include "qtv.h"
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#define curtime Sys_Milliseconds()
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void NET_SendPacket(SOCKET sock, int length, char *data, netadr_t adr)
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{
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int ret;
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ret = sendto(sock, data, length, 0, (struct sockaddr *)adr, sizeof(struct sockaddr_in));
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if (ret < 0)
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{
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printf("udp send error\n");
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}
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}
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#define PACKET_HEADER 8
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/*
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packet header
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-------------
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31 sequence
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1 does this message contain a reliable payload
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31 acknowledge sequence
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1 acknowledge receipt of even/odd message
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16 qport
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The remote connection never knows if it missed a reliable message, the
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local side detects that it has been dropped by seeing a sequence acknowledge
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higher than the last reliable sequence, but without the correct even/odd
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bit for the reliable set.
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If the sender notices that a reliable message has been dropped, it will be
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retransmitted. It will not be retransmitted again until a message after
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the retransmit has been acknowledged and the reliable still failed to get there.
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If the sequence number is -1, the packet should be handled without a netcon.
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The reliable message can be added to at any time by doing
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MSG_Write* (&netchan->message, <data>).
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If the message buffer is overflowed, either by a single message, or by
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multiple frames worth piling up while the last reliable transmit goes
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unacknowledged, the netchan signals a fatal error.
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Reliable messages are always placed first in a packet, then the unreliable
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message is included if there is sufficient room.
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To the receiver, there is no distinction between the reliable and unreliable
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parts of the message, they are just processed out as a single larger message.
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Illogical packet sequence numbers cause the packet to be dropped, but do
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not kill the connection. This, combined with the tight window of valid
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reliable acknowledgement numbers provides protection against malicious
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address spoofing.
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The qport field is a workaround for bad address translating routers that
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sometimes remap the client's source port on a packet during gameplay.
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If the base part of the net address matches and the qport matches, then the
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channel matches even if the IP port differs. The IP port should be updated
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to the new value before sending out any replies.
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*/
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/*
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===============
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Netchan_OutOfBand
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Sends an out-of-band datagram
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================
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*/
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void Netchan_OutOfBand (SOCKET sock, netadr_t adr, int length, unsigned char *data)
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{
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netmsg_t send;
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unsigned char send_buf[MAX_MSGLEN + PACKET_HEADER];
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// write the packet header
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InitNetMsg (&send, send_buf, sizeof(send_buf));
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WriteLong (&send, -1); // -1 sequence means out of band
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WriteData (&send, data, length);
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// send the datagram
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NET_SendPacket (sock, send.cursize, send.data, adr);
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}
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/*
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===============
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Netchan_OutOfBandPrint
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Sends a text message in an out-of-band datagram
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================
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*/
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void Netchan_OutOfBandPrint (SOCKET sock, netadr_t adr, char *format, ...)
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{
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va_list argptr;
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static char string[8192]; // ??? why static?
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va_start (argptr, format);
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#ifdef _WIN32
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_vsnprintf (string, sizeof(string) - 1, format, argptr);
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string[sizeof(string) - 1] = '\0';
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#else
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vsnprintf (string, sizeof(string), format, argptr);
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#endif // _WIN32
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va_end (argptr);
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Netchan_OutOfBand (sock, adr, strlen(string), (unsigned char *)string);
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}
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/*
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===============
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Netchan_Init
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===============
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*/
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void Netchan_Init (netadr_t adr)
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{
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}
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/*
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==============
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Netchan_Setup
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called to open a channel to a remote system
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==============
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*/
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void Netchan_Setup (SOCKET sock, netchan_t *chan, netadr_t adr, int qport)
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{
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memset (chan, 0, sizeof(*chan));
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chan->sock = sock;
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memcpy(&chan->remote_address, adr, sizeof(netadr_t));
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chan->qport = qport;
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chan->last_received = curtime;
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InitNetMsg(&chan->message, chan->message_buf, sizeof(chan->message_buf));
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chan->message.allowoverflow = true;
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chan->rate = 1.0f/2500;
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}
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/*
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===============
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Netchan_CanPacket
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Returns true if the bandwidth choke isn't active
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================
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*/
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#define MAX_BACKUP 200
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qboolean Netchan_CanPacket (netchan_t *chan)
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{
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// unlimited bandwidth for local client
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// if (chan->remote_address.type == NA_LOOPBACK)
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// return true;
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if (chan->cleartime < curtime + MAX_BACKUP*chan->rate)
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return true;
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return false;
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}
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/*
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===============
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Netchan_CanReliable
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Returns true if the bandwidth choke isn't
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================
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*/
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qboolean Netchan_CanReliable (netchan_t *chan)
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{
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if (chan->reliable_length)
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return false; // waiting for ack
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return Netchan_CanPacket (chan);
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}
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/*
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===============
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Netchan_Transmit
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tries to send an unreliable message to a connection, and handles the
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transmition / retransmition of the reliable messages.
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A 0 length will still generate a packet and deal with the reliable messages.
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================
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*/
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void Netchan_Transmit (netchan_t *chan, int length, const unsigned char *data)
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{
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netmsg_t send;
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unsigned char send_buf[MAX_MSGLEN + PACKET_HEADER];
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qboolean send_reliable;
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unsigned w1, w2;
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// check for message overflow
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if (chan->message.overflowed)
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{
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chan->drop = true;
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// printf ("%s:Outgoing message overflow\n"
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// , NET_AdrToString (chan->remote_address));
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return;
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}
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// if the remote side dropped the last reliable message, resend it
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send_reliable = false;
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if (chan->incoming_acknowledged > chan->last_reliable_sequence
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&& chan->incoming_reliable_acknowledged != chan->reliable_sequence)
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send_reliable = true;
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// if the reliable transmit buffer is empty, copy the current message out
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if (!chan->reliable_length && chan->message.cursize)
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{
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memcpy (chan->reliable_buf, chan->message_buf, chan->message.cursize);
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chan->reliable_length = chan->message.cursize;
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chan->message.cursize = 0;
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chan->reliable_sequence ^= 1;
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send_reliable = true;
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}
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// write the packet header
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send.data = send_buf;
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send.maxsize = sizeof(send_buf);
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send.readpos = send.cursize = 0;
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w1 = chan->outgoing_sequence | (send_reliable<<31);
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w2 = chan->incoming_sequence | (chan->incoming_reliable_sequence<<31);
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chan->outgoing_sequence++;
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WriteLong (&send, w1);
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WriteLong (&send, w2);
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// send the qport if we are a client
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// if (chan->sock == NS_CLIENT)
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// MSG_WriteShort (&send, chan->qport);
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// copy the reliable message to the packet first
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if (send_reliable)
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{
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WriteData (&send, chan->reliable_buf, chan->reliable_length);
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chan->last_reliable_sequence = chan->outgoing_sequence;
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}
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// add the unreliable part if space is available
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if (send.maxsize - send.cursize >= length)
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WriteData (&send, data, length);
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// send the datagram
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// i = chan->outgoing_sequence & (MAX_LATENT-1);
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// chan->outgoing_size[i] = send.cursize;
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// chan->outgoing_time[i] = curtime;
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NET_SendPacket (chan->sock, send.cursize, send.data, chan->remote_address);
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if (chan->cleartime < curtime)
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chan->cleartime = curtime + send.cursize*chan->rate;
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else
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chan->cleartime += send.cursize*chan->rate;
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#ifndef CLIENTONLY
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// if (chan->sock == NS_SERVER && sv_paused.value)
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// chan->cleartime = curtime;
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#endif
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/* if (showpackets.value)
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Com_Printf ("--> s=%i(%i) a=%i(%i) %i\n"
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, chan->outgoing_sequence
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, send_reliable
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, chan->incoming_sequence
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, chan->incoming_reliable_sequence
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, send.cursize);
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*/
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}
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/*
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=================
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Netchan_Process
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called when the current net_message is from remote_address
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modifies net_message so that it points to the packet payload
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=================
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*/
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qboolean Netchan_Process (netchan_t *chan, netmsg_t *msg)
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{
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unsigned sequence, sequence_ack;
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unsigned reliable_ack, reliable_message;
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// get sequence numbers
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msg->readpos = 0;
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sequence = ReadLong (msg);
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sequence_ack = ReadLong (msg);
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// read the qport if we are a server
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// if (chan->sock == NS_SERVER)
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ReadShort (msg);
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reliable_message = sequence >> 31;
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reliable_ack = sequence_ack >> 31;
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sequence &= ~(1<<31);
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sequence_ack &= ~(1<<31);
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/* if (showpackets.value)
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Com_Printf ("<-- s=%i(%i) a=%i(%i) %i\n"
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, sequence
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, reliable_message
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, sequence_ack
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, reliable_ack
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, net_message.cursize);
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*/
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//
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// discard stale or duplicated packets
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//
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if (sequence <= (unsigned)chan->incoming_sequence)
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{
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/* if (showdrop.value)
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Com_Printf ("%s:Out of order packet %i at %i\n"
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, NET_AdrToString (chan->remote_address)
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, sequence
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, chan->incoming_sequence);
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*/
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return false;
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}
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//
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// dropped packets don't keep the message from being used
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//
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/* chan->dropped = sequence - (chan->incoming_sequence+1);
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if (chan->dropped > 0)
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{
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chan->drop_count += 1;
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if (showdrop.value)
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Com_Printf ("%s:Dropped %i packets at %i\n"
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, NET_AdrToString (chan->remote_address)
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, chan->dropped
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, sequence);
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}
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*/
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//
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// if the current outgoing reliable message has been acknowledged
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// clear the buffer to make way for the next
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//
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if (reliable_ack == (unsigned)chan->reliable_sequence)
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chan->reliable_length = 0; // it has been received
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//
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// if this message contains a reliable message, bump incoming_reliable_sequence
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//
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chan->incoming_sequence = sequence;
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chan->incoming_acknowledged = sequence_ack;
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chan->incoming_reliable_acknowledged = reliable_ack;
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if (reliable_message)
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chan->incoming_reliable_sequence ^= 1;
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//
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// the message can now be read from the current message pointer
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// update statistics counters
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//
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// chan->frame_latency = chan->frame_latency*OLD_AVG
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// + (chan->outgoing_sequence-sequence_ack)*(1.0-OLD_AVG);
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// chan->frame_rate = chan->frame_rate*OLD_AVG
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// + (curtime - chan->last_received)*(1.0-OLD_AVG);
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// chan->good_count += 1;
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chan->last_received = curtime;
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return true;
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}
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