COMM.C

/*++ 
 
Copyright 1996 - 1998 Microsoft Corporation 
 
Module Name: 
 
    comm.c 
 
Abstract: 
 
    Implements a set of common operations for socket communication 
 
Revision History: 
 
--*/ 
 
#include <windows.h> 
#include <winsock.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include "comm.h" 
 
BOOL InitWinsock () 
{ 
int nRes; 
WSADATA wsaData; 
WORD wVerRequested = 0x0101; // ver 1.1 
 
// Init the sockets interface 
nRes = WSAStartup (wVerRequested, &wsaData); 
if (nRes)  { 
fprintf (stderr, "Couldn't init winsock: %d\n", nRes); 
return(FALSE); 
} 
 
return(TRUE); 
} 
 
BOOL TermWinsock () 
{ 
if (SOCKET_ERROR == WSACleanup ()) 
return(FALSE); 
else 
return(TRUE); 
} 
 
BOOL SendMsg (SOCKET s, PBYTE pBuf, DWORD cbBuf) 
/*++ 
 
 Routine Description: 
 
    Sends a message over the socket by first sending a DWORD that 
represents the size of the message followed by the message itself. 
 
 Return Value: 
 
    Returns TRUE is successful; otherwise FALSE is returned. 
 
--*/ 
{ 
if (0 == cbBuf) 
return(TRUE); 
 
// send the size of the message 
// 
if (!SendBytes (s, (PBYTE)&cbBuf, sizeof (cbBuf))) 
return(FALSE); 
 
// send the body of the message 
// 
if (!SendBytes (s, pBuf, cbBuf)) 
return(FALSE); 
 
return(TRUE); 
} 
 
BOOL ReceiveMsg (SOCKET s, PBYTE pBuf, DWORD cbBuf, DWORD *pcbRead) 
/*++ 
 
 Routine Description: 
 
    Receives a message over the socket.  The first DWORD in the message 
will be the message size.  The remainder of the bytes will be the 
actual message. 
 
 Return Value: 
 
    Returns TRUE is successful; otherwise FALSE is returned. 
 
--*/ 
{ 
DWORD cbRead; 
DWORD cbData; 
 
// find out how much data is in the message 
// 
if (!ReceiveBytes (s, (PBYTE)&cbData, sizeof (cbData), &cbRead)) 
return(FALSE); 
 
if (sizeof (cbData) != cbRead) 
return(FALSE); 
 
// Read the full message 
// 
if (!ReceiveBytes (s, pBuf, cbData, &cbRead)) 
return(FALSE); 
 
if (cbRead != cbData) 
return(FALSE); 
 
*pcbRead = cbRead; 
 
return(TRUE); 
} 
 
BOOL SendBytes (SOCKET s, PBYTE pBuf, DWORD cbBuf) 
{ 
PBYTE pTemp = pBuf; 
int cbSent, cbRemaining = cbBuf; 
 
if (0 == cbBuf) 
return(TRUE); 
 
while (cbRemaining) { 
cbSent = send (s, pTemp, cbRemaining, 0); 
if (SOCKET_ERROR == cbSent) { 
fprintf (stderr, "send failed: %u\n", GetLastError ()); 
return FALSE; 
} 
 
pTemp += cbSent; 
cbRemaining -= cbSent; 
} 
 
return TRUE; 
} 
 
BOOL ReceiveBytes (SOCKET s, PBYTE pBuf, DWORD cbBuf, DWORD *pcbRead) 
{ 
PBYTE pTemp = pBuf; 
int cbRead, cbRemaining = cbBuf; 
 
while (cbRemaining) { 
cbRead = recv (s, pTemp, cbRemaining, 0); 
if (0 == cbRead) 
break; 
 
if (SOCKET_ERROR == cbRead) { 
fprintf (stderr, "recv failed: %u\n", GetLastError ()); 
return FALSE; 
} 
 
cbRemaining -= cbRead; 
pTemp += cbRead; 
} 
 
*pcbRead = cbBuf - cbRemaining; 
 
return TRUE; 
}