ref: bf5dc91f8d7bc2035effd18290c523050fa1b2cd
dir: /code/qcommon/net_chan.c/
/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
This file is part of Quake III Arena source code.
Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
===========================================================================
*/
#include "../game/q_shared.h"
#include "qcommon.h"
/*
packet header
-------------
4 outgoing sequence. high bit will be set if this is a fragmented message
[2 qport (only for client to server)]
[2 fragment start byte]
[2 fragment length. if < FRAGMENT_SIZE, this is the last fragment]
if the sequence number is -1, the packet should be handled as an out-of-band
message instead of as part of a netcon.
All fragments will have the same sequence numbers.
The qport field is a workaround for bad address translating routers that
sometimes remap the client's source port on a packet during gameplay.
If the base part of the net address matches and the qport matches, then the
channel matches even if the IP port differs. The IP port should be updated
to the new value before sending out any replies.
*/
#define MAX_PACKETLEN 1400 // max size of a network packet
#define FRAGMENT_SIZE (MAX_PACKETLEN - 100)
#define PACKET_HEADER 10 // two ints and a short
#define FRAGMENT_BIT (1<<31)
cvar_t *showpackets;
cvar_t *showdrop;
cvar_t *qport;
static char *netsrcString[2] = {
"client",
"server"
};
/*
===============
Netchan_Init
===============
*/
void Netchan_Init( int port ) {
port &= 0xffff;
showpackets = Cvar_Get ("showpackets", "0", CVAR_TEMP );
showdrop = Cvar_Get ("showdrop", "0", CVAR_TEMP );
qport = Cvar_Get ("net_qport", va("%i", port), CVAR_INIT );
}
/*
==============
Netchan_Setup
called to open a channel to a remote system
==============
*/
void Netchan_Setup( netsrc_t sock, netchan_t *chan, netadr_t adr, int qport ) {
Com_Memset (chan, 0, sizeof(*chan));
chan->sock = sock;
chan->remoteAddress = adr;
chan->qport = qport;
chan->incomingSequence = 0;
chan->outgoingSequence = 1;
}
/*
=================
Netchan_TransmitNextFragment
Send one fragment of the current message
=================
*/
void Netchan_TransmitNextFragment( netchan_t *chan ) {
msg_t send;
byte send_buf[MAX_PACKETLEN];
int fragmentLength;
// write the packet header
MSG_InitOOB (&send, send_buf, sizeof(send_buf)); // <-- only do the oob here
MSG_WriteLong( &send, chan->outgoingSequence | FRAGMENT_BIT );
// send the qport if we are a client
if ( chan->sock == NS_CLIENT ) {
MSG_WriteShort( &send, qport->integer );
}
// copy the reliable message to the packet first
fragmentLength = FRAGMENT_SIZE;
if ( chan->unsentFragmentStart + fragmentLength > chan->unsentLength ) {
fragmentLength = chan->unsentLength - chan->unsentFragmentStart;
}
MSG_WriteShort( &send, chan->unsentFragmentStart );
MSG_WriteShort( &send, fragmentLength );
MSG_WriteData( &send, chan->unsentBuffer + chan->unsentFragmentStart, fragmentLength );
// send the datagram
NET_SendPacket(chan->sock, send.cursize, send.data, &chan->remoteAddress );
if ( showpackets->integer ) {
Com_Printf ("%s send %4i : s=%i fragment=%i,%i\n"
, netsrcString[ chan->sock ]
, send.cursize
, chan->outgoingSequence
, chan->unsentFragmentStart, fragmentLength);
}
chan->unsentFragmentStart += fragmentLength;
// this exit condition is a little tricky, because a packet
// that is exactly the fragment length still needs to send
// a second packet of zero length so that the other side
// can tell there aren't more to follow
if ( chan->unsentFragmentStart == chan->unsentLength && fragmentLength != FRAGMENT_SIZE ) {
chan->outgoingSequence++;
chan->unsentFragments = qfalse;
}
}
/*
===============
Netchan_Transmit
Sends a message to a connection, fragmenting if necessary
A 0 length will still generate a packet.
================
*/
void Netchan_Transmit( netchan_t *chan, int length, const byte *data ) {
msg_t send;
byte send_buf[MAX_PACKETLEN];
if ( length > MAX_MSGLEN ) {
Com_Error( ERR_DROP, "Netchan_Transmit: length = %i", length );
}
chan->unsentFragmentStart = 0;
// fragment large reliable messages
if ( length >= FRAGMENT_SIZE ) {
chan->unsentFragments = qtrue;
chan->unsentLength = length;
Com_Memcpy( chan->unsentBuffer, data, length );
// only send the first fragment now
Netchan_TransmitNextFragment( chan );
return;
}
// write the packet header
MSG_InitOOB (&send, send_buf, sizeof(send_buf));
MSG_WriteLong( &send, chan->outgoingSequence );
chan->outgoingSequence++;
// send the qport if we are a client
if ( chan->sock == NS_CLIENT ) {
MSG_WriteShort( &send, qport->integer );
}
MSG_WriteData( &send, data, length );
// send the datagram
NET_SendPacket(chan->sock, send.cursize, send.data, &chan->remoteAddress );
if ( showpackets->integer ) {
Com_Printf( "%s send %4i : s=%i ack=%i\n"
, netsrcString[ chan->sock ]
, send.cursize
, chan->outgoingSequence - 1
, chan->incomingSequence );
}
}
/*
=================
Netchan_Process
Returns qfalse if the message should not be processed due to being
out of order or a fragment.
Msg must be large enough to hold MAX_MSGLEN, because if this is the
final fragment of a multi-part message, the entire thing will be
copied out.
=================
*/
qboolean Netchan_Process( netchan_t *chan, msg_t *msg ) {
int sequence;
int qport;
int fragmentStart, fragmentLength;
qboolean fragmented;
// XOR unscramble all data in the packet after the header
// Netchan_UnScramblePacket( msg );
// get sequence numbers
MSG_BeginReadingOOB( msg );
sequence = MSG_ReadLong( msg );
// check for fragment information
if ( sequence & FRAGMENT_BIT ) {
sequence &= ~FRAGMENT_BIT;
fragmented = qtrue;
} else {
fragmented = qfalse;
}
// read the qport if we are a server
if ( chan->sock == NS_SERVER ) {
qport = MSG_ReadShort( msg );
}
// read the fragment information
if ( fragmented ) {
fragmentStart = MSG_ReadShort( msg );
fragmentLength = MSG_ReadShort( msg );
} else {
fragmentStart = 0; // stop warning message
fragmentLength = 0;
}
if ( showpackets->integer ) {
if ( fragmented ) {
Com_Printf( "%s recv %4i : s=%i fragment=%i,%i\n"
, netsrcString[ chan->sock ]
, msg->cursize
, sequence
, fragmentStart, fragmentLength );
} else {
Com_Printf( "%s recv %4i : s=%i\n"
, netsrcString[ chan->sock ]
, msg->cursize
, sequence );
}
}
//
// discard out of order or duplicated packets
//
if ( sequence <= chan->incomingSequence ) {
if ( showdrop->integer || showpackets->integer ) {
Com_Printf( "%s:Out of order packet %i at %i\n"
, chan->remoteAddress.sys
, sequence
, chan->incomingSequence );
}
return qfalse;
}
//
// dropped packets don't keep the message from being used
//
chan->dropped = sequence - (chan->incomingSequence+1);
if ( chan->dropped > 0 ) {
if ( showdrop->integer || showpackets->integer ) {
Com_Printf( "%s:Dropped %i packets at %i\n"
, chan->remoteAddress.sys
, chan->dropped
, sequence );
}
}
//
// if this is the final framgent of a reliable message,
// bump incoming_reliable_sequence
//
if ( fragmented ) {
// TTimo
// make sure we add the fragments in correct order
// either a packet was dropped, or we received this one too soon
// we don't reconstruct the fragments. we will wait till this fragment gets to us again
// (NOTE: we could probably try to rebuild by out of order chunks if needed)
if ( sequence != chan->fragmentSequence ) {
chan->fragmentSequence = sequence;
chan->fragmentLength = 0;
}
// if we missed a fragment, dump the message
if ( fragmentStart != chan->fragmentLength ) {
if ( showdrop->integer || showpackets->integer ) {
Com_Printf( "%s:Dropped a message fragment\n"
, chan->remoteAddress.sys
, sequence);
}
// we can still keep the part that we have so far,
// so we don't need to clear chan->fragmentLength
return qfalse;
}
// copy the fragment to the fragment buffer
if ( fragmentLength < 0 || msg->readcount + fragmentLength > msg->cursize ||
chan->fragmentLength + fragmentLength > sizeof( chan->fragmentBuffer ) ) {
if ( showdrop->integer || showpackets->integer ) {
Com_Printf ("%s:illegal fragment length\n"
, chan->remoteAddress.sys);
}
return qfalse;
}
Com_Memcpy( chan->fragmentBuffer + chan->fragmentLength,
msg->data + msg->readcount, fragmentLength );
chan->fragmentLength += fragmentLength;
// if this wasn't the last fragment, don't process anything
if ( fragmentLength == FRAGMENT_SIZE ) {
return qfalse;
}
if ( chan->fragmentLength > msg->maxsize ) {
Com_Printf( "%s:fragmentLength %i > msg->maxsize\n"
, chan->remoteAddress.sys,
chan->fragmentLength );
return qfalse;
}
// copy the full message over the partial fragment
// make sure the sequence number is still there
*(int *)msg->data = LittleLong( sequence );
Com_Memcpy( msg->data + 4, chan->fragmentBuffer, chan->fragmentLength );
msg->cursize = chan->fragmentLength + 4;
chan->fragmentLength = 0;
msg->readcount = 4; // past the sequence number
msg->bit = 32; // past the sequence number
// TTimo
// clients were not acking fragmented messages
chan->incomingSequence = sequence;
return qtrue;
}
//
// the message can now be read from the current message pointer
//
chan->incomingSequence = sequence;
return qtrue;
}
//==============================================================================
/*
===================
NET_CompareBaseAdr
Compares without the port
===================
*/
qboolean NET_CompareBaseAdr(netadr_t *a, netadr_t *b)
{
if (a->type != b->type)
return qfalse;
if (a->type == NA_LOOPBACK)
return qtrue;
if (a->type == NA_IP)
{
if(strcmp(a->addr, b->addr) == 0)
return qtrue;
return qfalse;
}
Com_Printf ("NET_CompareBaseAdr: bad address type\n");
return qfalse;
}
const char *NET_AdrToString(netadr_t *a)
{
if (a->type == NA_LOOPBACK) {
return "loopback";
} else if (a->type == NA_BOT) {
return "bot";
} else if (a->type == NA_IP) {
return a->sys;
} else {
Com_Printf ("NET_AdrToString: bad address type\n");
return nil;
}
}
qboolean NET_CompareAdr (netadr_t *a, netadr_t *b)
{
if (a->type != b->type)
return qfalse;
if (a->type == NA_LOOPBACK)
return qtrue;
if (a->type == NA_IP)
{
if(strcmp(a->sys, b->sys) == 0)
return qtrue;
return qfalse;
}
Com_Printf ("NET_CompareAdr: bad address type\n");
return qfalse;
}
qboolean NET_IsLocalAddress( netadr_t *adr ) {
return adr->type == NA_LOOPBACK;
}
/*
=============================================================================
LOOPBACK BUFFERS FOR LOCAL PLAYER
=============================================================================
*/
// there needs to be enough loopback messages to hold a complete
// gamestate of maximum size
#define MAX_LOOPBACK 16
typedef struct {
byte data[MAX_PACKETLEN];
int datalen;
} loopmsg_t;
typedef struct {
loopmsg_t msgs[MAX_LOOPBACK];
int get, send;
} loopback_t;
loopback_t loopbacks[2];
qboolean NET_GetLoopPacket (netsrc_t sock, netadr_t *net_from, msg_t *net_message)
{
int i;
loopback_t *loop;
loop = &loopbacks[sock];
if (loop->send - loop->get > MAX_LOOPBACK)
loop->get = loop->send - MAX_LOOPBACK;
if (loop->get >= loop->send)
return qfalse;
i = loop->get & (MAX_LOOPBACK-1);
loop->get++;
Com_Memcpy (net_message->data, loop->msgs[i].data, loop->msgs[i].datalen);
net_message->cursize = loop->msgs[i].datalen;
Com_Memset (net_from, 0, sizeof(*net_from));
net_from->type = NA_LOOPBACK;
return qtrue;
}
void NET_SendLoopPacket (netsrc_t sock, int length, const void *data, netadr_t *to)
{
int i;
loopback_t *loop;
loop = &loopbacks[sock^1];
i = loop->send & (MAX_LOOPBACK-1);
loop->send++;
Com_Memcpy (loop->msgs[i].data, data, length);
loop->msgs[i].datalen = length;
}
//=============================================================================
void NET_SendPacket( netsrc_t sock, int length, const void *data, netadr_t *to ) {
// sequenced packets are shown in netchan, so just show oob
if ( showpackets->integer && *(int *)data == -1 ) {
Com_Printf ("send packet %4i\n", length);
}
if ( to->type == NA_LOOPBACK ) {
NET_SendLoopPacket (sock, length, data, to);
return;
}
if ( to->type == NA_BOT ) {
return;
}
if ( to->type == NA_BAD ) {
return;
}
Sys_SendPacket( length, data, to );
}
/*
===============
NET_OutOfBandPrint
Sends a text message in an out-of-band datagram
================
*/
void QDECL NET_OutOfBandPrint( netsrc_t sock, netadr_t *adr, const char *format, ... ) {
va_list argptr;
char string[MAX_MSGLEN];
// set the header
string[0] = -1;
string[1] = -1;
string[2] = -1;
string[3] = -1;
va_start( argptr, format );
vsprintf( string+4, format, argptr );
va_end( argptr );
// send the datagram
NET_SendPacket( sock, strlen( string ), string, adr );
}
/*
===============
NET_OutOfBandPrint
Sends a data message in an out-of-band datagram (only used for "connect")
================
*/
void QDECL NET_OutOfBandData( netsrc_t sock, netadr_t *adr, byte *format, int len ) {
byte string[MAX_MSGLEN*2];
int i;
msg_t mbuf;
// set the header
string[0] = 0xff;
string[1] = 0xff;
string[2] = 0xff;
string[3] = 0xff;
for(i=0;i<len;i++) {
string[i+4] = format[i];
}
mbuf.data = string;
mbuf.cursize = len+4;
Huff_Compress( &mbuf, 12);
// send the datagram
NET_SendPacket( sock, mbuf.cursize, mbuf.data, adr );
}
/*
=============
NET_StringToAdr
Traps "localhost" for loopback, passes everything else to system
=============
*/
qboolean NET_StringToAdr( const char *s, netadr_t *a ) {
qboolean r;
if (!strcmp (s, "localhost")) {
Com_Memset (a, 0, sizeof(*a));
a->type = NA_LOOPBACK;
return qtrue;
}
r = Sys_StringToAdr(s, a);
if ( !r ) {
a->type = NA_BAD;
return qfalse;
}
return qtrue;
}