dnet.cpp

Public Functions

DefineEngineFunction(DNetSetLogging , void , (bool enabled) , "(bool enabled)" "@brief Enables logging of the connection <a href="/coding/file/cmdscan_8cpp/#cmdscan_8cpp_1aeab71244afb687f16d8c4f5ee9d6ef0e">protocols\n\n</a>" "When enabled <a href="/coding/file/pointer_8h/#pointer_8h_1aeeddce917cf130d62c370b8f216026dd">a</a> lot of network debugging information is sent <a href="/coding/file/cmdgram_8cpp/#cmdgram_8cpp_1a5bafda9519252aa2d0fd038153f77dca">to</a> the <a href="/coding/file/cmdscan_8cpp/#cmdscan_8cpp_1aeab71244afb687f16d8c4f5ee9d6ef0e">console.\n</a>" "@param enabled True <a href="/coding/file/cmdgram_8cpp/#cmdgram_8cpp_1a5bafda9519252aa2d0fd038153f77dca">to</a> enable, false <a href="/coding/file/cmdgram_8cpp/#cmdgram_8cpp_1a5bafda9519252aa2d0fd038153f77dca">to</a> <a href="/coding/file/cmdscan_8cpp/#cmdscan_8cpp_1aeab71244afb687f16d8c4f5ee9d6ef0e">disable\n</a>" " @ingroup Networking" )

  1
  2//-----------------------------------------------------------------------------
  3// Copyright (c) 2012 GarageGames, LLC
  4//
  5// Permission is hereby granted, free of charge, to any person obtaining a copy
  6// of this software and associated documentation files (the "Software"), to
  7// deal in the Software without restriction, including without limitation the
  8// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  9// sell copies of the Software, and to permit persons to whom the Software is
 10// furnished to do so, subject to the following conditions:
 11//
 12// The above copyright notice and this permission notice shall be included in
 13// all copies or substantial portions of the Software.
 14//
 15// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 18// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 19// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 20// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 21// IN THE SOFTWARE.
 22//-----------------------------------------------------------------------------
 23
 24#include "core/stream/bitStream.h"
 25#include "core/dnet.h"
 26#include "core/strings/stringFunctions.h"
 27
 28#include "console/consoleTypes.h"
 29#include "console/engineAPI.h"
 30
 31
 32bool gLogToConsole = false;
 33
 34S32 gNetBitsReceived = 0;
 35
 36enum NetPacketType
 37{
 38   DataPacket,
 39   PingPacket,
 40   AckPacket,
 41   InvalidPacketType,
 42};
 43
 44static const char *packetTypeNames[] =
 45{
 46   "DataPacket",
 47   "PingPacket",
 48   "AckPacket",
 49};
 50
 51//-----------------------------------------------------------------
 52//-----------------------------------------------------------------
 53//-----------------------------------------------------------------
 54DefineEngineFunction( DNetSetLogging, void, (bool enabled), , "(bool enabled)"
 55   "@brief Enables logging of the connection protocols\n\n"
 56   "When enabled a lot of network debugging information is sent to the console.\n"
 57   "@param enabled True to enable, false to disable\n"
 58   "@ingroup Networking")
 59{
 60   gLogToConsole = enabled;
 61}
 62
 63ConnectionProtocol::ConnectionProtocol()
 64{
 65   mLastSeqRecvd = 0;
 66   mHighestAckedSeq = 0;
 67   mLastSendSeq = 0; // start sending at 1
 68   mAckMask = 0;
 69   mLastRecvAckAck = 0;
 70   mConnectionEstablished = false;
 71}
 72void ConnectionProtocol::buildSendPacketHeader(BitStream *stream, S32 packetType)
 73{
 74   S32 ackByteCount = ((mLastSeqRecvd - mLastRecvAckAck + 7) >> 3);
 75   AssertFatal(ackByteCount <= 4, "Too few ack bytes!");
 76
 77   // S32 headerSize = 3 + ackByteCount;
 78
 79   if(packetType == DataPacket)
 80      mLastSendSeq++;
 81
 82   stream->writeFlag(true);
 83   stream->writeInt(mConnectSequence & 1, 1);
 84   stream->writeInt(mLastSendSeq & 0x1FF, 9);
 85   stream->writeInt(mLastSeqRecvd & 0x1FF, 9);
 86   stream->writeInt(packetType & 0x3, 2);
 87   stream->writeInt(ackByteCount & 0x7, 3);
 88   U32 bitmask = ~(0xFFFFFFFF << (ackByteCount*8));
 89   if(ackByteCount == 4)
 90   {
 91      // Performing a bit shift that is the same size as the variable being shifted
 92      // is undefined in the C/C++ standard.  Handle that exception here when
 93      // ackByteCount*8 == 4*8 == 32
 94      bitmask = 0xFFFFFFFF;
 95   }
 96   stream->writeInt(mAckMask & bitmask, ackByteCount * 8);
 97
 98   // if we're resending this header, we can't advance the
 99   // sequence recieved (in case this packet drops and the prev one
100   // goes through)
101
102   if(gLogToConsole)
103      Con::printf("build hdr %d %d", mLastSendSeq, packetType);
104
105   if(packetType == DataPacket)
106      mLastSeqRecvdAtSend[mLastSendSeq & 0x1F] = mLastSeqRecvd;
107}
108
109void ConnectionProtocol::sendPingPacket()
110{
111   U8 buffer[16];
112   BitStream bs(buffer, 16);
113   buildSendPacketHeader(&bs, PingPacket);
114   if(gLogToConsole)
115      Con::printf("send ping %d", mLastSendSeq);
116
117   sendPacket(&bs);
118}
119
120void ConnectionProtocol::sendAckPacket()
121{
122   U8 buffer[16];
123   BitStream bs(buffer, 16);
124   buildSendPacketHeader(&bs, AckPacket);
125   if(gLogToConsole)
126      Con::printf("send ack %d", mLastSendSeq);
127
128   sendPacket(&bs);
129}
130
131// packets are read directly into the data portion of
132// connection notify packets... makes the events easier to post into
133// the system.
134
135void ConnectionProtocol::processRawPacket(BitStream *pstream)
136{
137   // read in the packet header:
138
139   // Fixed packet header: 3 bytes
140   //
141   //   1 bit game packet flag
142   //   1 bit connect sequence
143   //   9 bits packet seq number
144   //   9 bits ackstart seq number
145   //   2 bits packet type
146   //   2 bits ack byte count
147   //
148   // type is:
149   //    00 data packet
150   //    01 ping packet
151   //    02 ack packet
152
153   // next 1-4 bytes are ack flags
154   //
155   //   header len is 4-9 bytes
156   //   average case 4 byte header
157
158   gNetBitsReceived = pstream->getStreamSize();
159
160   pstream->readFlag(); // get rid of the game info packet bit
161   U32 pkConnectSeqBit  = pstream->readInt(1);
162   U32 pkSequenceNumber = pstream->readInt(9);
163   U32 pkHighestAck     = pstream->readInt(9);
164   U32 pkPacketType     = pstream->readInt(2);
165   S32 pkAckByteCount   = pstream->readInt(3);
166
167   // check connection sequence bit
168   if(pkConnectSeqBit != (mConnectSequence & 1))
169      return;
170
171   if(pkAckByteCount > 4 || pkPacketType >= InvalidPacketType)
172      return;
173
174   S32 pkAckMask = pstream->readInt(8 * pkAckByteCount);
175
176   // verify packet ordering and acking and stuff
177   // check if the 9-bit sequence is within the packet window
178   // (within 31 packets of the last received sequence number).
179
180   pkSequenceNumber |= (mLastSeqRecvd & 0xFFFFFE00);
181   // account for wrap around
182   if(pkSequenceNumber < mLastSeqRecvd)
183      pkSequenceNumber += 0x200;
184
185   if(pkSequenceNumber > mLastSeqRecvd + 31)
186   {
187      // the sequence number is outside the window... must be out of order
188      // discard.
189      return;
190   }
191
192   pkHighestAck |= (mHighestAckedSeq & 0xFFFFFE00);
193   // account for wrap around
194
195   if(pkHighestAck < mHighestAckedSeq)
196      pkHighestAck += 0x200;
197
198   if(pkHighestAck > mLastSendSeq)
199   {
200      // the ack number is outside the window... must be an out of order
201      // packet, discard.
202      return;
203   }
204
205   if(gLogToConsole)
206   {
207      for(U32 i = mLastSeqRecvd+1; i < pkSequenceNumber; i++)
208         Con::printf("Not recv %d", i);
209      Con::printf("Recv %d %s", pkSequenceNumber, packetTypeNames[pkPacketType]);
210   }
211
212   // shift up the ack mask by the packet difference
213   // this essentially nacks all the packets dropped
214
215   mAckMask <<= pkSequenceNumber - mLastSeqRecvd;
216
217   // if this packet is a data packet (i.e. not a ping packet or an ack packet), ack it
218   if(pkPacketType == DataPacket)
219      mAckMask |= 1;
220
221   // do all the notifies...
222   for(U32 i = mHighestAckedSeq+1; i <= pkHighestAck; i++)
223   {
224      bool packetTransmitSuccess = pkAckMask & (1 << (pkHighestAck - i));
225      handleNotify(packetTransmitSuccess);
226      if(gLogToConsole)
227         Con::printf("Ack %d %d", i, packetTransmitSuccess);
228
229      if(packetTransmitSuccess)
230      {
231         mLastRecvAckAck = mLastSeqRecvdAtSend[i & 0x1F];
232         if(!mConnectionEstablished)
233         {
234            mConnectionEstablished = true;
235            handleConnectionEstablished();
236         }
237      }
238   }
239
240   // the other side knows more about its window than we do.
241   if(pkSequenceNumber - mLastRecvAckAck > 32)
242      mLastRecvAckAck = pkSequenceNumber - 32;
243
244   mHighestAckedSeq = pkHighestAck;
245
246   // first things first...
247   // ackback any pings or accept connects
248
249   if(pkPacketType == PingPacket)
250   {
251      // send an ack to the other side
252      // the ack will have the same packet sequence as our last sent packet
253      // if the last packet we sent was the connection accepted packet
254      // we must resend that packet
255      sendAckPacket();
256   }
257   keepAlive(); // notification that the connection is ok
258
259   // note: handlePacket() may delete the connection if an error occurs.
260   if(mLastSeqRecvd != pkSequenceNumber)
261   {
262      mLastSeqRecvd = pkSequenceNumber;
263      if(pkPacketType == DataPacket)
264         handlePacket(pstream);
265   }
266}
267
268bool ConnectionProtocol::windowFull()
269{
270   return mLastSendSeq - mHighestAckedSeq >= 30;
271}
272
273void ConnectionProtocol::writeDemoStartBlock(ResizeBitStream *stream)
274{
275   for(U32 i = 0; i < 32; i++)
276      stream->write(mLastSeqRecvdAtSend[i]);
277   stream->write(mLastSeqRecvd);
278   stream->write(mHighestAckedSeq);
279   stream->write(mLastSendSeq);
280   stream->write(mAckMask);
281   stream->write(mConnectSequence);
282   stream->write(mLastRecvAckAck);
283   stream->write(mConnectionEstablished);
284}
285
286bool ConnectionProtocol::readDemoStartBlock(BitStream *stream)
287{
288   for(U32 i = 0; i < 32; i++)
289      stream->read(&mLastSeqRecvdAtSend[i]);
290   stream->read(&mLastSeqRecvd);
291   stream->read(&mHighestAckedSeq);
292   stream->read(&mLastSendSeq);
293   stream->read(&mAckMask);
294   stream->read(&mConnectSequence);
295   stream->read(&mLastRecvAckAck);
296   stream->read(&mConnectionEstablished);
297   return true;
298}
299