SIMPLEC.C

/******************************************************************************\ 
* simplec.c - Simple TCP/UDP client using Winsock 1.1 
*  
*       This is a part of the Microsoft Source Code Samples. 
*       Copyright 1996 - 1998 Microsoft Corporation. 
*       All rights reserved. 
*       This source code is only intended as a supplement to 
*       Microsoft Development Tools and/or WinHelp documentation. 
*       See these sources for detailed information regarding the 
*       Microsoft samples programs. 
\******************************************************************************/ 
 
#define WIN32_LEAN_AND_MEAN 
#include <winsock2.h> 
#include <stdlib.h> 
#include <stdio.h> 
#include <string.h> 
 
#define DEFAULT_PORT 5001 
#define DEFAULT_PROTO SOCK_STREAM // TCP 
 
void Usage(char *progname) { 
fprintf(stderr,"Usage\n%s -p [protocol] -n [server] -e [endpoint] \ 
-l [iterations]\n", 
progname); 
fprintf(stderr,"Where:\n\tprotocol is one of TCP or UDP\n"); 
fprintf(stderr,"\tserver is the IP address or name of server\n"); 
fprintf(stderr,"\tendpoint is the port to listen on\n"); 
fprintf(stderr,"\titerations is the number of loops to execute\n"); 
fprintf(stderr,"\t(-l by itself makes client run in an infinite loop,"); 
fprintf(stderr," Hit Ctrl-C to terminate it)\n"); 
fprintf(stderr,"Defaults are TCP , localhost and 5001\n"); 
WSACleanup(); 
exit(1); 
} 
int main(int argc, char **argv) { 
 
char Buffer[128]; 
char *server_name= "localhost"; 
unsigned short port = DEFAULT_PORT; 
int retval, loopflag=0; 
int i, loopcount,maxloop=-1; 
unsigned int addr; 
int socket_type = DEFAULT_PROTO; 
struct sockaddr_in server; 
struct hostent *hp; 
WSADATA wsaData; 
SOCKET  conn_socket; 
 
if (argc >1) { 
for(i=1;i <argc;i++) { 
if ( (argv[i][0] == '-') || (argv[i][0] == '/') ) { 
switch(tolower(argv[i][1])) { 
case 'p': 
if (!stricmp(argv[i+1], "TCP") ) 
socket_type = SOCK_STREAM; 
else if (!stricmp(argv[i+1], "UDP") ) 
socket_type = SOCK_DGRAM; 
else 
Usage(argv[0]); 
i++; 
break; 
 
case 'n': 
server_name = argv[++i]; 
break; 
case 'e': 
port = atoi(argv[++i]); 
break; 
case 'l': 
loopflag =1; 
if (argv[i+1]) { 
if (argv[i+1][0] != '-')  
maxloop = atoi(argv[i+1]); 
} 
else 
maxloop = -1; 
i++; 
break; 
default: 
Usage(argv[0]); 
break; 
} 
} 
else 
Usage(argv[0]); 
} 
} 
 
if (WSAStartup(0x202,&wsaData) == SOCKET_ERROR) { 
fprintf(stderr,"WSAStartup failed with error %d\n",WSAGetLastError()); 
WSACleanup(); 
return -1; 
} 
 
if (port == 0){ 
Usage(argv[0]); 
} 
 
// 
// Attempt to detect if we should call gethostbyname() or 
// gethostbyaddr() 
 
if (isalpha(server_name[0])) {   /* server address is a name */ 
hp = gethostbyname(server_name); 
} 
else  { /* Convert nnn.nnn address to a usable one */ 
addr = inet_addr(server_name); 
hp = gethostbyaddr((char *)&addr,4,AF_INET); 
} 
if (hp == NULL ) { 
fprintf(stderr,"Client: Cannot resolve address [%s]: Error %d\n", 
server_name,WSAGetLastError()); 
WSACleanup(); 
exit(1); 
} 
 
// 
// Copy the resolved information into the sockaddr_in structure 
// 
memset(&server,0,sizeof(server)); 
memcpy(&(server.sin_addr),hp->h_addr,hp->h_length); 
server.sin_family = hp->h_addrtype; 
server.sin_port = htons(port); 
 
conn_socket = socket(AF_INET,socket_type,0); /* Open a socket */ 
if (conn_socket <0 ) { 
fprintf(stderr,"Client: Error Opening socket: Error %d\n", 
WSAGetLastError()); 
WSACleanup(); 
return -1; 
} 
 
// 
// Notice that nothing in this code is specific to whether we  
// are using UDP or TCP. 
// We achieve this by using a simple trick. 
//    When connect() is called on a datagram socket, it does not  
//    actually establish the connection as a stream (TCP) socket 
//    would. Instead, TCP/IP establishes the remote half of the 
//    ( LocalIPAddress, LocalPort, RemoteIP, RemotePort) mapping. 
//    This enables us to use send() and recv() on datagram sockets, 
//    instead of recvfrom() and sendto() 
 
 
printf("Client connecting to: %s\n",hp->h_name); 
if (connect(conn_socket,(struct sockaddr*)&server,sizeof(server)) 
== SOCKET_ERROR) { 
fprintf(stderr,"connect() failed: %d\n",WSAGetLastError()); 
WSACleanup(); 
return -1; 
} 
 
// cook up a string to send 
// 
loopcount =0; 
while(1) { 
wsprintf(Buffer,"This is a small test message [number %d]",loopcount++); 
retval = send(conn_socket,Buffer,sizeof(Buffer),0); 
if (retval == SOCKET_ERROR) { 
fprintf(stderr,"send() failed: error %d\n",WSAGetLastError()); 
WSACleanup(); 
return -1; 
} 
printf("Sent Data [%s]\n",Buffer); 
retval = recv(conn_socket,Buffer,sizeof (Buffer),0 ); 
if (retval == SOCKET_ERROR) { 
fprintf(stderr,"recv() failed: error %d\n",WSAGetLastError()); 
closesocket(conn_socket); 
WSACleanup(); 
return -1; 
} 
// 
// We are not likely to see this with UDP, since there is no 
// 'connection' established.  
// 
if (retval == 0) { 
printf("Server closed connection\n"); 
closesocket(conn_socket); 
WSACleanup(); 
return -1; 
} 
printf("Received %d bytes, data [%s] from server\n",retval,Buffer); 
if (!loopflag){ 
printf("Terminating connection\n"); 
break; 
} 
else { 
if ( (loopcount >= maxloop) && (maxloop >0) ) 
break; 
} 
} 
closesocket(conn_socket); 
WSACleanup(); 
}