home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
The CICA Windows Explosion!
/
The CICA Windows Explosion! - Disc 2.iso
/
winsock
/
twnsck12.zip
/
SRC\PACKET.C
< prev
next >
Wrap
Text File
|
1994-12-03
|
16KB
|
642 lines
/*
* TwinSock - "Troy's Windows Sockets"
*
* Copyright (C) 1994 Troy Rollo <troy@cbme.unsw.EDU.AU>
*
* This program 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.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdio.h>
#ifdef __MSDOS__
#include <winsock.h>
#include <stdlib.h>
#else
#include <sys/types.h>
#include <netinet/in.h>
#endif
#include "packet.h"
#define MAX_STREAMS 256
#define WINDOW_SIZE 4
short nInSeq = 0;
short nOutSeq = 0;
extern int SendData(void *pvData, int nBytes);
static unsigned long crc_32_tab[] = { /* CRC polynomial 0xedb88320 */
0x00000000l, 0x77073096l, 0xee0e612cl, 0x990951bal, 0x076dc419l, 0x706af48fl, 0xe963a535l, 0x9e6495a3l,
0x0edb8832l, 0x79dcb8a4l, 0xe0d5e91el, 0x97d2d988l, 0x09b64c2bl, 0x7eb17cbdl, 0xe7b82d07l, 0x90bf1d91l,
0x1db71064l, 0x6ab020f2l, 0xf3b97148l, 0x84be41del, 0x1adad47dl, 0x6ddde4ebl, 0xf4d4b551l, 0x83d385c7l,
0x136c9856l, 0x646ba8c0l, 0xfd62f97al, 0x8a65c9ecl, 0x14015c4fl, 0x63066cd9l, 0xfa0f3d63l, 0x8d080df5l,
0x3b6e20c8l, 0x4c69105el, 0xd56041e4l, 0xa2677172l, 0x3c03e4d1l, 0x4b04d447l, 0xd20d85fdl, 0xa50ab56bl,
0x35b5a8fal, 0x42b2986cl, 0xdbbbc9d6l, 0xacbcf940l, 0x32d86ce3l, 0x45df5c75l, 0xdcd60dcfl, 0xabd13d59l,
0x26d930acl, 0x51de003al, 0xc8d75180l, 0xbfd06116l, 0x21b4f4b5l, 0x56b3c423l, 0xcfba9599l, 0xb8bda50fl,
0x2802b89el, 0x5f058808l, 0xc60cd9b2l, 0xb10be924l, 0x2f6f7c87l, 0x58684c11l, 0xc1611dabl, 0xb6662d3dl,
0x76dc4190l, 0x01db7106l, 0x98d220bcl, 0xefd5102al, 0x71b18589l, 0x06b6b51fl, 0x9fbfe4a5l, 0xe8b8d433l,
0x7807c9a2l, 0x0f00f934l, 0x9609a88el, 0xe10e9818l, 0x7f6a0dbbl, 0x086d3d2dl, 0x91646c97l, 0xe6635c01l,
0x6b6b51f4l, 0x1c6c6162l, 0x856530d8l, 0xf262004el, 0x6c0695edl, 0x1b01a57bl, 0x8208f4c1l, 0xf50fc457l,
0x65b0d9c6l, 0x12b7e950l, 0x8bbeb8eal, 0xfcb9887cl, 0x62dd1ddfl, 0x15da2d49l, 0x8cd37cf3l, 0xfbd44c65l,
0x4db26158l, 0x3ab551cel, 0xa3bc0074l, 0xd4bb30e2l, 0x4adfa541l, 0x3dd895d7l, 0xa4d1c46dl, 0xd3d6f4fbl,
0x4369e96al, 0x346ed9fcl, 0xad678846l, 0xda60b8d0l, 0x44042d73l, 0x33031de5l, 0xaa0a4c5fl, 0xdd0d7cc9l,
0x5005713cl, 0x270241aal, 0xbe0b1010l, 0xc90c2086l, 0x5768b525l, 0x206f85b3l, 0xb966d409l, 0xce61e49fl,
0x5edef90el, 0x29d9c998l, 0xb0d09822l, 0xc7d7a8b4l, 0x59b33d17l, 0x2eb40d81l, 0xb7bd5c3bl, 0xc0ba6cadl,
0xedb88320l, 0x9abfb3b6l, 0x03b6e20cl, 0x74b1d29al, 0xead54739l, 0x9dd277afl, 0x04db2615l, 0x73dc1683l,
0xe3630b12l, 0x94643b84l, 0x0d6d6a3el, 0x7a6a5aa8l, 0xe40ecf0bl, 0x9309ff9dl, 0x0a00ae27l, 0x7d079eb1l,
0xf00f9344l, 0x8708a3d2l, 0x1e01f268l, 0x6906c2fel, 0xf762575dl, 0x806567cbl, 0x196c3671l, 0x6e6b06e7l,
0xfed41b76l, 0x89d32be0l, 0x10da7a5al, 0x67dd4accl, 0xf9b9df6fl, 0x8ebeeff9l, 0x17b7be43l, 0x60b08ed5l,
0xd6d6a3e8l, 0xa1d1937el, 0x38d8c2c4l, 0x4fdff252l, 0xd1bb67f1l, 0xa6bc5767l, 0x3fb506ddl, 0x48b2364bl,
0xd80d2bdal, 0xaf0a1b4cl, 0x36034af6l, 0x41047a60l, 0xdf60efc3l, 0xa867df55l, 0x316e8eefl, 0x4669be79l,
0xcb61b38cl, 0xbc66831al, 0x256fd2a0l, 0x5268e236l, 0xcc0c7795l, 0xbb0b4703l, 0x220216b9l, 0x5505262fl,
0xc5ba3bbel, 0xb2bd0b28l, 0x2bb45a92l, 0x5cb36a04l, 0xc2d7ffa7l, 0xb5d0cf31l, 0x2cd99e8bl, 0x5bdeae1dl,
0x9b64c2b0l, 0xec63f226l, 0x756aa39cl, 0x026d930al, 0x9c0906a9l, 0xeb0e363fl, 0x72076785l, 0x05005713l,
0x95bf4a82l, 0xe2b87a14l, 0x7bb12bael, 0x0cb61b38l, 0x92d28e9bl, 0xe5d5be0dl, 0x7cdcefb7l, 0x0bdbdf21l,
0x86d3d2d4l, 0xf1d4e242l, 0x68ddb3f8l, 0x1fda836el, 0x81be16cdl, 0xf6b9265bl, 0x6fb077e1l, 0x18b74777l,
0x88085ae6l, 0xff0f6a70l, 0x66063bcal, 0x11010b5cl, 0x8f659effl, 0xf862ae69l, 0x616bffd3l, 0x166ccf45l,
0xa00ae278l, 0xd70dd2eel, 0x4e048354l, 0x3903b3c2l, 0xa7672661l, 0xd06016f7l, 0x4969474dl, 0x3e6e77dbl,
0xaed16a4al, 0xd9d65adcl, 0x40df0b66l, 0x37d83bf0l, 0xa9bcae53l, 0xdebb9ec5l, 0x47b2cf7fl, 0x30b5ffe9l,
0xbdbdf21cl, 0xcabac28al, 0x53b39330l, 0x24b4a3a6l, 0xbad03605l, 0xcdd70693l, 0x54de5729l, 0x23d967bfl,
0xb3667a2el, 0xc4614ab8l, 0x5d681b02l, 0x2a6f2b94l, 0xb40bbe37l, 0xc30c8ea1l, 0x5a05df1bl, 0x2d02ef8dl
};
#define UPDC32(octet, crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))
static short
CalcCRC(data, size)
char *data;
int size;
{
unsigned long crc = 0xffff;
while (size--)
{
crc = UPDC32(*data++, crc);
}
crc = ~crc;
return (crc & 0xffff);
}
struct packet_queue
{
int idPacket;
int iPacketLen;
int iStream;
int iFlags;
struct packet *pkt;
struct packet_queue *ppqNext;
};
#define PQF_LEADER 0x0001
#define PQF_TRAILER 0x0002
static struct packet_queue *ppqList = 0;
static int iInitialised = 0;
static struct packet_queue *appqStreams[MAX_STREAMS];
static struct packet_queue *ppqSent = 0;
static int nSent = 0;
static struct packet_queue *ppqReceived = 0;
static char aiStreams[MAX_STREAMS / 8];
#define STREAM_BIT(x) (1 << (((x) + 1) % 8))
#define STREAM_BYTE(x) aiStreams[((x) + 1) / 8]
#define SET_STREAM(x) (STREAM_BYTE(x) |= STREAM_BIT(x))
#define CLR_STREAM(x) (STREAM_BYTE(x) &= ~STREAM_BIT(x))
#define GET_STREAM(x) ((STREAM_BYTE(x) & STREAM_BIT(x)) != 0)
static char ach6bit[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789./";
void PoppedPacket(struct packet_queue *ppqPopped);
void PutInQueue(struct packet_queue *ppq, int iStream);
void InsertInQueue(struct packet_queue **pppqNext, struct packet_queue *ppq)
{
for (; *pppqNext; pppqNext = &((*pppqNext)->ppqNext));
*pppqNext = ppq;
}
void FlushQueue(struct packet_queue **pppq)
{
struct packet_queue *ppqPop;
while ((ppqPop = *pppq) != 0)
{
*pppq = ppqPop->ppqNext;
free(ppqPop->pkt);
free(ppqPop);
}
}
int TransmitData(void *pvData, int iDataLen)
{
char *pchDataIn;
char *pchDataOut;
char c;
int iIn, iOut;
int nBits;
int nBitsLeft;
int nBitsNow;
int nDataOut;
char cNow, cTmp;
nDataOut = iDataLen * 4 / 3 + 1;
if (iDataLen % 6)
nDataOut++;
pchDataIn = (char *) pvData;
pchDataOut = (char *) malloc(nDataOut);
nBits = nBitsLeft = 0;
cNow = 0;
pchDataOut[0] = '@'; /* Signals the receiving end to realign to bit 0 */
for (iIn = 0, iOut = 1; iOut < nDataOut;)
{
if (nBitsLeft)
{
cTmp = c & ((1 << nBitsLeft) - 1);
nBitsNow = 6 - nBits;
if (nBitsLeft < nBitsNow)
nBitsNow = nBitsLeft;
cNow <<= nBitsNow;
cTmp >>= nBitsLeft - nBitsNow;
cTmp &= ((1 << nBitsNow) - 1);
cNow |= cTmp;
nBits += nBitsNow;
nBitsLeft -= nBitsNow;
if (nBits == 6)
{
pchDataOut[iOut++] = ach6bit[cNow];
cNow = 0;
nBits = 0;
}
}
else
{
if (iIn < iDataLen)
c = pchDataIn[iIn++];
else
c = 0;
nBitsLeft = 8;
}
}
nDataOut = SendData(pchDataOut, nDataOut);
free(pchDataOut);
return nDataOut;
}
static void
TransmitPacket(struct packet_queue *ppqList)
{
TransmitData(ppqList->pkt, ppqList->iPacketLen);
SetTransmitTimeout();
}
void
InsertIntoIncoming(struct packet *pkt, int iLen)
{
struct packet_queue *ppq;
struct packet_queue **pppq;
struct packet *pktNew;
int iPacketID;
iPacketID = ntohs(pkt->iPacketID);
for ( pppq = &ppqReceived;
*pppq && (*pppq)->idPacket < iPacketID;
pppq = &(*pppq)->ppqNext);
if ((*pppq) && (*pppq)->idPacket == iPacketID)
return;
pktNew = (struct packet *) malloc(sizeof(struct packet));
*pktNew = *pkt;
ppq = (struct packet_queue *) malloc(sizeof(struct packet_queue));
ppq->ppqNext = *pppq;
ppq->idPacket = iPacketID;
ppq->pkt = pktNew;
ppq->iPacketLen = iLen;
*pppq = ppq;
while (ppqReceived && ppqReceived->idPacket == nInSeq)
{
nInSeq++;
DataReceived(ppqReceived->pkt->achData,
ppqReceived->iPacketLen - sizeof(short) * 4);
ppq = ppqReceived;
ppqReceived = ppq->ppqNext;
free(ppq->pkt);
free(ppq);
}
}
void TimeoutReceived(void)
{
struct packet_queue *ppq;
for (ppq = ppqSent; ppq; ppq = ppq->ppqNext)
TransmitPacket(ppq);
}
void InitHead()
{
struct packet *pkt;
short nCRC;
ppqList->idPacket = nOutSeq;
pkt = ppqList->pkt;
pkt->iPacketID = htons(nOutSeq);
nCRC = CalcCRC(pkt, ppqList->iPacketLen);
pkt->nCRC = htons(nCRC);
nOutSeq++;
}
void TransmitHead(void)
{
struct packet_queue *ppq;
if (nSent < WINDOW_SIZE)
{
nSent++;
ppq = ppqList;
ppqList = ppq->ppqNext;
ppq->ppqNext = 0;
InsertInQueue(&ppqSent, ppq);
PoppedPacket(ppq);
TransmitPacket(ppq);
}
}
static void
AckReceived(int id)
{
struct packet_queue **pppq, *ppqTemp;
for (pppq = &ppqSent;
*pppq && (*pppq)->idPacket != id;
pppq = &(*pppq)->ppqNext);
if (*pppq)
{
while (ppqSent != *pppq)
{
ppqTemp = ppqSent;
ppqSent = ppqTemp->ppqNext;
ppqTemp->ppqNext = 0;
InsertInQueue(&ppqSent, ppqTemp);
TransmitPacket(ppqTemp);
}
ppqTemp = ppqSent;
ppqSent = ppqTemp->ppqNext;
free(ppqTemp->pkt);
free(ppqTemp);
nSent--;
if (ppqList)
TransmitHead();
if (!ppqSent)
KillTransmitTimeout();
}
}
void FlushStream(int iStream)
{
FlushQueue(appqStreams + iStream + 1);
}
void PutInQueue(struct packet_queue *ppq, int iStream)
{
if (iStream == -2) /* Urgent */
{
InsertInQueue(&ppqList, ppq);
}
else if (GET_STREAM(iStream) &&
(appqStreams[iStream + 1] ||
(ppq->iFlags & PQF_LEADER)))
{
InsertInQueue(appqStreams + iStream + 1, ppq);
}
else
{
SET_STREAM(iStream);
InsertInQueue(&ppqList, ppq);
}
if (ppqList == ppq)
{
InitHead();
TransmitHead();
}
}
void PoppedPacket(struct packet_queue *ppqPopped)
{
int iStream, iFlags;
struct packet_queue *ppqPop;
iStream = ppqPopped->iStream;
iFlags = ppqPopped->iFlags;
if (iStream != -2 && (iFlags & PQF_TRAILER))
{
if (appqStreams[iStream + 1])
{
do
{
ppqPop = appqStreams[iStream + 1];
appqStreams[iStream + 1] = ppqPop->ppqNext;
ppqPop->ppqNext = 0;
InsertInQueue(&ppqList, ppqPop);
} while (!(ppqPop->iFlags & PQF_TRAILER));
}
else
{
CLR_STREAM(iStream);
}
}
if (ppqList)
{
InitHead();
TransmitHead();
}
}
void SendPacket(void *pvData, int iDataLen, int iStream, int iFlags)
{
struct packet *pkt;
struct packet_queue *ppq;
short nCRC;
if (!iInitialised)
{
iInitialised = 1;
memset(aiStreams, 0, sizeof(aiStreams));
memset(appqStreams, 0, sizeof(appqStreams));
}
pkt = (struct packet *) malloc(sizeof(struct packet));
ppq = (struct packet_queue *) malloc(sizeof(struct packet_queue));
ppq->iPacketLen = iDataLen + sizeof(short) * 4;
ppq->iStream = iStream;
ppq->pkt = pkt;
ppq->ppqNext = 0;
ppq->iFlags = iFlags;
pkt->iPacketLen = htons(iDataLen);
pkt->nCRC = 0;
pkt->nType = htons((short) PT_Data);
memcpy(pkt->achData, pvData, iDataLen);
PutInQueue(ppq, iStream);
}
void TransmitAck(short id)
{
struct packet pkt;
int nCRC;
pkt.iPacketLen = 0;
pkt.nCRC = 0;
pkt.nType = htons((short) PT_Ack);
pkt.iPacketID = htons(id);
nCRC = CalcCRC(&pkt, sizeof(short) * 4);
pkt.nCRC = htons(nCRC);
TransmitData(&pkt, sizeof(short) * 4);
}
void ProcessData(void *pvData, int nDataLen)
{
static struct packet pkt;
static int nBytes = 0;
int nToCopy;
int nData;
enum packet_type pt;
short iLen;
short nCRC;
short id;
short iLocation;
if (!pvData) /* Receive timeout */
{
nBytes = 0;
return;
}
while (nDataLen)
{
if (nBytes < sizeof(short) * 4)
{
nToCopy = sizeof(short) * 4 - nBytes;
if (nToCopy > nDataLen)
nToCopy = nDataLen;
memcpy((char *) &pkt + nBytes, pvData, nToCopy);
pvData = (char *) pvData + nToCopy;
nDataLen -= nToCopy;
nBytes += nToCopy;
}
if (nBytes < sizeof(short) * 4)
break;
pt = (enum packet_type) ntohs(pkt.nType);
iLen = ntohs(pkt.iPacketLen);
nCRC = ntohs(pkt.nCRC);
id = ntohs(pkt.iPacketID);
if (iLen > PACKET_MAX || iLen < 0) /* Sanity check */
{
nBytes = 0;
nDataLen = 0;
KillReceiveTimeout();
if (ppqList)
KillTransmitTimeout();
FlushInput();
if (ppqList)
SetTransmitTimeout();
return;
}
if (nBytes < sizeof(short) * 4 + iLen)
{
nToCopy = sizeof(short) * 4 + iLen - nBytes;
if (nDataLen < nToCopy)
nToCopy = nDataLen;
memcpy((char *) &pkt + nBytes, pvData, nToCopy);
pvData = (char *) pvData + nToCopy;
nDataLen -= nToCopy;
nBytes += nToCopy;
}
if (nBytes == sizeof(short) * 4 + iLen)
{
nBytes = 0;
pkt.nCRC = 0;
if (CalcCRC(&pkt, iLen + sizeof(short) * 4) == nCRC)
{
switch(pt)
{
case PT_Data:
iLocation = nInSeq - id;
TransmitAck(id);
if (iLocation <= 0)
InsertIntoIncoming(&pkt, iLen + sizeof(short) * 4);
break;
case PT_Nak:
if (ppqList &&
id == ppqList->idPacket)
TransmitHead();
break;
case PT_Ack:
AckReceived(id);
break;
case PT_Shutdown:
Shutdown(0);
break;
}
}
else
{
/* If we flush input we should also
* reset any tranmit timeout, otherwise
* we may resend the packet while flushing,
* and flush the Ack. We also kill any
* receive timeout because we have already
* "flushed" any existing input.
*/
KillReceiveTimeout();
if (ppqList)
KillTransmitTimeout();
FlushInput();
if (ppqList)
SetTransmitTimeout();
return;
}
}
}
if (nBytes)
SetReceiveTimeout();
}
void PacketReceiveData(void *pvData, int nDataLen)
{
static int nBits = 0;
static char c = 0;
static int nCtlX = 0;
char cIn;
char cTmp;
int nBitsLeft = 0;
int iOut = 0;
int nBitsNow;
char *pchDataOut;
char *pchDataIn;
if (!pvData)
{
ProcessData(0, nDataLen);
nBits = nBitsLeft = 0;
return;
}
KillReceiveTimeout();
pchDataIn = (char *) pvData;
pchDataOut = (char *) malloc(nDataLen);
while (nDataLen || nBitsLeft)
{
if (nBitsLeft)
{
nBitsNow = 8 - nBits;
if (nBitsLeft < nBitsNow)
nBitsNow = nBitsLeft;
c <<= nBitsNow;
cTmp = cIn >> (nBitsLeft - nBitsNow);
cTmp &= ((1 << nBitsNow) - 1);
c |= cTmp;
nBits += nBitsNow;
nBitsLeft -= nBitsNow;
if (nBits == 8)
{
pchDataOut[iOut++] = c;
nBits = 0;
}
}
else
{
cIn = *pchDataIn++;
nDataLen--;
if (cIn == '\030') /* ^X */
{
nCtlX++;
if (nCtlX >= 5)
Shutdown();
continue;
}
else
{
nCtlX = 0;
}
if (cIn == '@')
{
cIn = c = 0;
nBitsLeft = 0;
nBits = 0;
}
else
{
if (cIn >= 'A' && cIn <= 'Z')
cIn -= 'A';
else if (cIn >= 'a' && cIn <= 'z')
cIn = cIn - 'a' + 26;
else if (cIn >= '0' && cIn <= '9')
cIn = cIn - '0' + 52;
else if (cIn == '.')
cIn = 62;
else if (cIn == '/')
cIn = 63;
else
continue;
nBitsLeft = 6;
}
}
}
ProcessData(pchDataOut, iOut);
free(pchDataOut);
}
void PacketTransmitData(void *pvData, int iDataLen, int iStream)
{
int iFlags = PQF_LEADER;
while (iDataLen > PACKET_MAX)
{
SendPacket(pvData, PACKET_MAX, iStream, iFlags);
pvData = (char *) pvData + PACKET_MAX;
iDataLen -= PACKET_MAX;
iFlags = 0;
}
iFlags |= PQF_TRAILER;
SendPacket(pvData, iDataLen, iStream, iFlags);
}
void
ReInitPackets(void)
{
int i;
nInSeq = nOutSeq = 0;
for (i = 0; i < MAX_STREAMS; i++)
FlushQueue(appqStreams + i);
FlushQueue(&ppqList);
memset(aiStreams, 0, sizeof(aiStreams));
}