client.cpp

一个简易dns 服务器

// Client.cpp : Defines the entry point for the console application.
//
// 1. open the *.c in the Visual C++, then "rebuild all".
// 2. click "yes" to create a project workspace.
// 3. You need to -add the library 'ws2_32.lib' to your project 
//    (Project -> Properties -> Linker -> Input -> Additional Dependencies) 
// 4. recompile the source.


#include "stdafx.h"
#include <winsock2.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#pragma   comment   (lib,"WS2_32.lib")

#define DEFAULT_PORT	5019
char szBuff[200];
SOCKET connect_sock;
int rece();
int send();
int msg_len;
time_t now;
FILE *stream;
int main(int argc, char **argv){
	
	
	int ctr;
	
	//int addr_len;
	struct sockaddr_in server_addr;
	struct hostent *hp;
	
	WSADATA wsaData;

	char			*server_name = "localhost";
	unsigned short	port = DEFAULT_PORT;
	unsigned int	addr;

	if (argc != 3){
		printf("echoscln [server name] [port number]\n");
		return -1;
	}
	else{
		server_name = argv[1];
		port = atoi(argv[2]);
	}

	if (WSAStartup(0x202, &wsaData) == SOCKET_ERROR){
		// stderr: standard error are printed to the screen.
		fprintf(stderr, "WSAStartup failed with error %d\n", WSAGetLastError());
		//WSACleanup function terminates use of the Windows Sockets DLL. 
		WSACleanup();
		return -1;
	}

	if (isalpha(server_name[0]))
		hp = gethostbyname(server_name);
	else{
		addr = inet_addr(server_name);
		hp = gethostbyaddr((char*)&addr, 4, AF_INET);
	}

	if (hp==NULL)
	{
		fprintf(stderr, "Cannot resolve address: %d\n", WSAGetLastError());
		WSACleanup();
		return -1;
	}

	//copy the resolved information into the sockaddr_in structure
	memset(&server_addr, 0, sizeof(server_addr));
	memcpy(&(server_addr.sin_addr), hp->h_addr, hp->h_length);
	server_addr.sin_family = hp->h_addrtype;
	server_addr.sin_port = htons(port);

	
	connect_sock = socket(AF_INET,SOCK_STREAM, 0);	//TCp socket


	if (connect_sock == INVALID_SOCKET){
		fprintf(stderr, "socket() failed with error %d\n", WSAGetLastError());
		WSACleanup();
		return -1;
	}

	printf("Client connecting to:GroupDns ==>%s\n", hp->h_name);

	if (connect(connect_sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) 
		== SOCKET_ERROR){
		fprintf(stderr, "connect() failed with error %d\n", WSAGetLastError());
		WSACleanup();
		return -1;
	}

fopen_s(&stream,"log.txt","a+");
while(true)
{
	printf("press '1' to receive message '2' to input words: (press 'ctrl + c'to quit)\n");
	scanf("%d",&ctr);
	
	switch(ctr)
	{
	case 2:

		
			send();
			break;
	case 1:
		
			rece();
			break;
	}

		

}

	closesocket(connect_sock);
	WSACleanup();
}
int send()
{
			memset(szBuff, 0,sizeof(szBuff));
			fflush(stdin);//clear the input stream
			printf("input your word:\n");
			gets(szBuff);
	
	

			msg_len = send(connect_sock, szBuff, sizeof(szBuff), 0);
	
			if (msg_len == SOCKET_ERROR){
				fprintf(stderr, "send() failed with error %d\n", WSAGetLastError());
				WSACleanup();
				return -1;
				}

			if (msg_len == 0){
				printf("server closed connection\n");
				closesocket(connect_sock);
				WSACleanup();
				return -1;
			}
			return 0;

}
 
DWORD WINAPI recThread(LPVOID pParam) 
{ 
memset(szBuff, 0,sizeof(szBuff));
msg_len = recv(connect_sock, szBuff, sizeof(szBuff), 0);
	return 1;
}
 
int rece()
{
 

			DWORD dwThreadId; 
HANDLE hThread = CreateThread(NULL, 0, recThread, NULL, 0, &dwThreadId); 
			
	 while(sizeof(szBuff)==0);
	 
	 time(&now);
	
	fprintf(stream,"\n\nThe Time : %s\n",ctime(&now));
	//fprintf(stream,"Sender   : %s\n",w);
	fprintf(stream,"Receive : %s\n",szBuff);		

			if (msg_len == SOCKET_ERROR){
			fprintf(stderr, "send() failed with error %d\n", WSAGetLastError());
			closesocket(connect_sock);
			WSACleanup();
			return -1;
			}

			if (msg_len <= 0){
			printf("retry\n");
			//closesocket(connect_sock);
			//WSACleanup();
			return 0;
			}
			if (msg_len == NULL){
			printf("Echo nothing");
			
			}
			else 
			{
				time(&now);
				printf(" %s |  %s  |.\n", ctime(&now),szBuff);
			}
			

			return 0;
			
}