www.pudn.com > UDP-based_Reliable_Data_Transfer_Library.zip > packet.cpp
/*****************************************************************************
Copyright © 2001 - 2006, The Board of Trustees of the University of Illinois.
All Rights Reserved.
UDP-based Data Transfer Library (UDT) version 3
Laboratory for Advanced Computing (LAC)
National Center for Data Mining (NCDM)
University of Illinois at Chicago
http://www.lac.uic.edu/
This library is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at
your option) any later version.
This library 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 Lesser
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*****************************************************************************/
/*****************************************************************************
This file contains the implementation of UDT packet handling modules.
A UDT packet is a 2-dimension vector of packet header and data.
*****************************************************************************/
/*****************************************************************************
written by
Yunhong Gu [gu@lac.uic.edu], last updated 02/14/2006
*****************************************************************************/
//////////////////////////////////////////////////////////////////////////////
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Packet Header |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | |
// ~ Data / Control Information Field ~
// | |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |0| Sequence Number |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |ff |o| Message Number |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Time Stamp |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// bit 0:
// 0: Data Packet
// 1: Control Packet
// bit ff:
// 11: solo message packet
// 10: first packet of a message
// 01: last packet of a message
// bit o:
// 0: in order delivery not required
// 1: in order delivery required
//
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |1| Type | Reserved |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Additional Info |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Time Stamp |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// bit 1-15:
// 0: Protocol Connection Handshake
// Add. Info: Undefined
// Control Info: Handshake information (see CHandShake)
// 1: Keep-alive
// Add. Info: Undefined
// Control Info: None
// 2: Acknowledgement (ACK)
// Add. Info: The ACK sequence number
// Control Info: The sequence number to which (but not include) all the previous packets have beed received
// Optional: RTT
// RTT Variance
// advertised flow window size (number of packets)
// estimated bandwidth (number of packets per second)
// 3: Negative Acknowledgement (NAK)
// Add. Info: Undefined
// Control Info: Loss list (see loss list coding below)
// 4: Congestion Warning
// Add. Info: Undefined
// Control Info: None
// 5: Shutdown
// Add. Info: Undefined
// Control Info: None
// 6: Acknowledgement of Acknowledement (ACK-square)
// Add. Info: The ACK sequence number
// Control Info: None
// 7: Message Drop Request
// Add. Info: Message ID
// Control Info: first sequence number of the message
// last seqeunce number of the message
// 65535: Explained by bits 16 - 31
//
// bit 16 - 31:
// This space is used for future expansion or user defined control packets.
//
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |1| Sequence Number a (first) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |0| Sequence Number b (last) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |0| Sequence Number (single) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// Loss List Field Coding:
// For any consectutive lost seqeunce numbers that the differnece between
// the last and first is more than 1, only record the first (a) and the
// the last (b) sequence numbers in the loss list field, and modify the
// the first bit of a to 1.
// For any single loss or consectutive loss less than 2 packets, use
// the original sequence numbers in the field.
#include "packet.h"
// Set up the aliases in the constructure
CPacket::CPacket():
m_iSeqNo((__int32&)(m_nHeader[0])),
m_iMsgNo((__int32&)(m_nHeader[1])),
m_iTimeStamp((__int32&)(m_nHeader[2])),
m_pcData((char*&)(m_PacketVector[1].iov_base))
{
m_PacketVector[0].iov_base = (char *)m_nHeader;
m_PacketVector[0].iov_len = CPacket::m_iPktHdrSize;
}
CPacket::~CPacket()
{
}
__int32 CPacket::getLength() const
{
return m_PacketVector[1].iov_len;
}
void CPacket::setLength(const __int32& len)
{
m_PacketVector[1].iov_len = len;
}
void CPacket::pack(const __int32& pkttype, void* lparam, void* rparam, const __int32& size)
{
// Set (bit-0 = 1) and (bit-1~15 = type)
m_nHeader[0] = 0x80000000 | (pkttype << 16);
// Set additional information and control information field
switch (pkttype)
{
case 2: //0010 - Acknowledgement (ACK)
// ACK packet seq. no.
if (NULL != lparam)
m_nHeader[1] = *(__int32 *)lparam;
// data ACK seq. no.
// optional: RTT (microsends), RTT variance (microseconds) advertised flow window size (packets), and estimated link capacity (packets per second)
m_PacketVector[1].iov_base = (char *)rparam;
m_PacketVector[1].iov_len = size;
break;
case 6: //0110 - Acknowledgement of Acknowledgement (ACK-2)
// ACK packet seq. no.
m_nHeader[1] = *(__int32 *)lparam;
// control info field should be none
// but "writev" does not allow this
m_PacketVector[1].iov_base = (char *)&__pad; //NULL;
m_PacketVector[1].iov_len = sizeof(__int32); //0;
break;
case 3: //0011 - Loss Report (NAK)
// loss list
m_PacketVector[1].iov_base = (char *)rparam;
m_PacketVector[1].iov_len = size;
break;
case 4: //0100 - Congestion Warning
// control info field should be none
// but "writev" does not allow this
m_PacketVector[1].iov_base = (char *)&__pad; //NULL;
m_PacketVector[1].iov_len = sizeof(__int32); //0
break;
case 1: //0001 - Keep-alive
// control info field should be none
// but "writev" does not allow this
m_PacketVector[1].iov_base = (char *)&__pad; //NULL;
m_PacketVector[1].iov_len = sizeof(__int32); //0
break;
case 0: //0000 - Handshake
// control info filed is handshake info
m_PacketVector[1].iov_base = (char *)rparam;
m_PacketVector[1].iov_len = size; //sizeof(CHandShake);
break;
case 5: //0101 - Shutdown
// control info field should be none
// but "writev" does not allow this
m_PacketVector[1].iov_base = (char *)&__pad; //NULL;
m_PacketVector[1].iov_len = sizeof(__int32); //0
break;
case 7: //0111 - Message Drop Request
// msg id
m_nHeader[1] = *(__int32 *)lparam;
//first seq no, last seq no
m_PacketVector[1].iov_base = (char *)rparam;
m_PacketVector[1].iov_len = size;
break;
case 65535: //0x7FFF - Reserved for user defined control packets
// for extended control packet
// "lparam" contains the extneded type information for bit 4 - 15
// "rparam" is the control information
m_nHeader[0] |= (*(__int32 *)lparam) << 16;
if (NULL != rparam)
{
m_PacketVector[1].iov_base = (char *)rparam;
m_PacketVector[1].iov_len = size;
}
else
{
m_PacketVector[1].iov_base = (char *)&__pad;
m_PacketVector[1].iov_len = sizeof(__int32);
}
break;
default:
break;
}
}
iovec* CPacket::getPacketVector()
{
return m_PacketVector;
}
__int32 CPacket::getFlag() const
{
// read bit 0
return m_nHeader[0] >> 31;
}
__int32 CPacket::getType() const
{
// read bit 1~15
return (m_nHeader[0] >> 16) & 0x00007FFF;
}
__int32 CPacket::getExtendedType() const
{
// read bit 16~31
return m_nHeader[0] & 0x0000FFFF;
}
__int32 CPacket::getAckSeqNo() const
{
// read additional information field
return m_nHeader[1];
}
__int32 CPacket::getMsgBoundary() const
{
// read [1] bit 0~1
return m_nHeader[1] >> 30;
}
__int32 CPacket::getMsgOrderFlag() const
{
// read [1] bit 2
return (m_nHeader[1] >> 29) & 1;
}
__int32 CPacket::getMsgSeq() const
{
// read [1] bit 3~31
return m_nHeader[1] & 0x1FFFFFFF;
}