网络编程简单例子(windows、linux)

windows:

TCP通信：

//client
#include <Winsock2.h>
#include <stdio.h>
void main()
{
	WORD wVersionRequested ;
	WSADATA wsaData ;
	int err;
	wVersionRequested = MAKEWORD( 1, 1) ;
	err = WSAStartup( wVersionRequested ,&wsaData );
	if(err != 0)
	{
		return ;
	}
	if(LOBYTE(wsaData.wVersion ) !=1 ||HIBYTE( wsaData.wVersion ) != 1)
	{
		WSACleanup();
		return ;
	}
	//创建套接字
	SOCKET sockClient = socket(AF_INET , SOCK_STREAM ,0) ;
	SOCKADDR_IN addrSrv ;
	addrSrv.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
	addrSrv.sin_family = AF_INET ;
	addrSrv.sin_port = htons(8000);
	connect(sockClient ,(SOCKADDR*)&addrSrv ,sizeof(SOCKADDR ));
	//接收数据；
	char recvBuf[100];
	recv(sockClient ,recvBuf,100,0) ;
	printf("recv :%s",recvBuf) ;
	send(sockClient ,"this is the client ",strlen("this is the client ") +1,0) ;
	closesocket(sockClient) ;
	WSACleanup ();

}

//server.cpp
#include <Winsock2.h>
#include <stdio.h>
void main()
{
	//
	WORD wVersionReguested ;
	WSADATA  wsaData ;
	int err;
	wVersionReguested = MAKEWORD( 1 ,1 );
	err = WSAStartup(wVersionReguested ,&wsaData ) ;
	if( err !=0 )
	{
		return ;
	}
	if(LOBYTE(wsaData.wVersion )!=1 || HIBYTE(wsaData.wVersion)!=1)
	{
		WSACleanup() ;
		return ;
	}
	SOCKET sockSrv = socket(AF_INET ,SOCK_STREAM, 0) ;
	SOCKADDR_IN addrSrv ;
	addrSrv.sin_addr.S_un.S_addr = htonl(INADDR_ANY) ;
	addrSrv.sin_family = AF_INET ;
	addrSrv.sin_port = htons(8000) ;
	//绑定套接字
	bind(sockSrv ,(SOCKADDR *)&addrSrv ,sizeof(SOCKADDR) );
	listen(sockSrv,5) ;
	SOCKADDR_IN addrClient ;
	int len = sizeof(SOCKADDR) ;
	while(1)
	{
		//等待客户请求的到来；
		SOCKET sockConn = accept(sockSrv ,(SOCKADDR*)&addrClient ,&len );
		char sendBuf[100];
		sprintf(sendBuf,"welcom %s here !\n",inet_ntoa(addrClient.sin_addr));
		//发送数据
		send(sockConn ,sendBuf ,strlen(sendBuf)+1,0) ;
		char recvBuf[100];
		recv(sockConn, recvBuf,100,0);
		printf("recv: %s\n",recvBuf) ;
		closesocket(sockConn) ;
	}
}

ＵＤＰ通信

服务端：

#include <stdio.h>
#include "winsock2.h"

void server() {

	WSADATA wsaData;
	SOCKET RecvSocket;
	sockaddr_in RecvAddr;
	int Port = 27015;
	char RecvBuf[1024];
	int  BufLen = 1024;
	sockaddr_in SenderAddr;
	int SenderAddrSize = sizeof(SenderAddr);

	//-----------------------------------------------
	// Initialize Winsock
	WSAStartup(MAKEWORD(2,2), &wsaData);

	//-----------------------------------------------
	// Create a receiver socket to receive datagrams
	RecvSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

	//-----------------------------------------------
	// Bind the socket to any address and the specified port.
	RecvAddr.sin_family = AF_INET;
	RecvAddr.sin_port = htons(Port);
	RecvAddr.sin_addr.s_addr = htonl(INADDR_ANY);

	bind(RecvSocket, (SOCKADDR *) &RecvAddr, sizeof(RecvAddr));

	//-----------------------------------------------
	// Call the recvfrom function to receive datagrams
	// on the bound socket.
	printf("Receiving datagrams...\n");
	while(1){
		memset(RecvBuf,0,sizeof(RecvBuf)) ;
		recvfrom(RecvSocket, 
			RecvBuf, 
			BufLen, 
			0, 
			(SOCKADDR *)&SenderAddr, 
			&SenderAddrSize);
		printf("from:%s::%s\n",inet_ntoa(SenderAddr.sin_addr),RecvBuf);
	}

	//-----------------------------------------------
	// Close the socket when finished receiving datagrams
	printf("Finished receiving. Closing socket.\n");
	closesocket(RecvSocket);

	//-----------------------------------------------
	// Clean up and exit.
	printf("Exiting.\n");
	WSACleanup();
	return;
}

客户端：

void client() {

	WSADATA wsaData;
	SOCKET SendSocket;
	sockaddr_in RecvAddr;
	int Port = 27015;
	char SendBuf[1024];
	int BufLen = 1024;

	//---------------------------------------------
	// Initialize Winsock
	WSAStartup(MAKEWORD(2,2), &wsaData);

	//---------------------------------------------
	// Create a socket for sending data
	SendSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

	//---------------------------------------------
	// Set up the RecvAddr structure with the IP address of
	// the receiver (in this example case "123.456.789.1")
	// and the specified port number.
	RecvAddr.sin_family = AF_INET;
	RecvAddr.sin_port = htons(Port);
	RecvAddr.sin_addr.s_addr = inet_addr("10.33.28.230");

	//---------------------------------------------
	// Send a datagram to the receiver
	printf("Sending a datagram to the receiver...\n");
	while(1){
		int n = scanf("%s",SendBuf);
		int res = sendto(SendSocket, 
			SendBuf, 
			n, 
			0, 
			(SOCKADDR *) &RecvAddr, 
			sizeof(RecvAddr));
		if(res==n){
			printf("send OK\n");
		}
	}


	//---------------------------------------------
	// When the application is finished sending, close the socket.
	printf("Finished sending. Closing socket.\n");
	closesocket(SendSocket);

	//---------------------------------------------
	// Clean up and quit.
	printf("Exiting.\n");
	WSACleanup();
	return;
}

linux版

UDP

服务器：

#include <stdio.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>

typedef struct sockaddr_in sockaddr_in ;
typedef struct sockaddr sockaddr ;
static inline int nonblock(int fd) {
	int opt;
	opt = fcntl(fd, F_GETFL);
	opt |= O_NONBLOCK;
	return fcntl(fd, F_SETFL, opt);
}
static inline int myblock(int fd) {
	int opt;
	opt = fcntl(fd, F_GETFL);
	opt &= ~O_NONBLOCK;
	return fcntl(fd, F_SETFL, opt);
}

int main(int argc ,char ** argv){
	sockaddr_in srv ,cli ;
	int sfd ;

	if((sfd=socket(AF_INET ,SOCK_DGRAM,0))==-1){
		perror("socket error:");
		return -1 ;
	}
	if(argc < 2){
		printf("please input argc with port num!");
		return -1 ;
	}

	memset(&srv,0,sizeof(srv));
	srv.sin_port = htons(atoi(argv[1]));
	srv.sin_family = AF_INET ;
	srv.sin_addr.s_addr = INADDR_ANY ;
	int bfd = bind(sfd , (sockaddr*)&srv,sizeof(sockaddr)) ;
	if(bfd==-1){
		perror("bind error:");
		return -1 ;
	}   
	char buf[1024] ;
	int len ,flags;
	static int count ;
	flags = MSG_WAITALL ;
	while(1){
		memset(buf,0,sizeof(buf));
		len = sizeof(cli);
		int rs,sum=0;

		/*              fcntl(sfd,F_SETFL,O_NONBLOCK);*/
		flags = 0 ; 
		while((rs = recvfrom(sfd,buf,sizeof(buf)-1,flags,(sockaddr*)&cli,&len))>0){
			printf("%s",buf);
			sum+=rs ;
			nonblock(sfd);
		}   
		printf("\n");
		myblock(sfd);
		/*fcntl(sfd,F_SETFL,O_NONBLOCK);*/
		printf("recv size:%d",sum);
		if(rs<0 && errno!=EAGAIN){
			perror("recvfrom:");
			continue ;
		}   

		printf("recv %d bytes from %s,contents:%s,count:=%d\n", 
			rs,inet_ntoa(cli.sin_addr),buf,count++);

	}   

	close(sfd);    

	return 0;
}

客户端：

#include <stdio.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
typedef struct sockaddr_in sockaddr_in ;
typedef struct sockaddr sockaddr ;


int main(int argc ,char ** argv){
	sockaddr_in srv ,cli ;
	int sfd ;

	if((sfd=socket(AF_INET ,SOCK_DGRAM,0))==-1){
		perror("socket error:");
		return -1 ;
	}
	if(argc < 3){
		printf("the argcs like : ./a.out ipaddr serverport  ");
		return -1 ;
	}

	memset(&srv,0,sizeof(srv));
	srv.sin_port = htons(atoi(argv[2]));
	srv.sin_family = AF_INET ;
	inet_aton(argv[1],&srv.sin_addr);

	char buf[1024] ;
	int len,snu,re;

	int64_t i ;
	/*      for(i=0;i<1000*1000*1000;i++){
	memset(buf,0,sizeof(buf)) ;
	sprintf(buf,"%d",i);
	snu = sendto(sfd,buf,strlen(buf),0,
	(sockaddr*)&srv,sizeof(sockaddr)) ;     
	}
	*/
	while(1){

		bzero(buf,sizeof(buf));
		re = read(STDIN_FILENO ,buf,sizeof(buf));
		snu = sendto(sfd,buf,re-1,0,
			(sockaddr*)&srv,sizeof(sockaddr)) ;
		printf("send %d bytes\n",snu);
	}
	close(sfd);

	return 0;
}

TCP

服务器：

#include <stdio.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
typedef struct sockaddr_in sockaddr_in ;
typedef struct sockaddr sockaddr ;
static inline int nonblock(int fd) {
	int opt;
	opt = fcntl(fd, F_GETFL);
	opt |= O_NONBLOCK;
	return fcntl(fd, F_SETFL, opt);
}

int main(int argc ,char ** argv){
	sockaddr_in srv ,cli ;
	int sfd ,sfd2;

	if((sfd=socket(AF_INET ,SOCK_STREAM,0))==-1){
		perror("socket error:");
		return -1 ;
	}
	if(argc < 2){
		printf("please input argc with port num!");
		return -1 ;
	}

	memset(&srv,0,sizeof(srv));
	srv.sin_port = htons(atoi(argv[1]));
	srv.sin_family = AF_INET ;

	srv.sin_addr.s_addr = INADDR_ANY ;
	int yes = 1;
	if (-1  == setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &yes,
		sizeof(int))) {
			close(sfd);
			return -1;
	}   
	int bfd = bind(sfd , (sockaddr*)&srv,sizeof(sockaddr)) ;
	if(bfd==-1){
		perror("bind error:");
		return -1 ;
	}   
	listen(sfd, 20) ;

	char buf[1024] ;
	int len ;
	while(1){
		len = sizeof(sockaddr);
		sfd2 = accept(sfd,(sockaddr*)&cli,&len);
		printf("accept a sock\n");
		memset(buf,0,sizeof(buf));
		nonblock(sfd2);
		while(1){
			int rs ;
			while(( rs = recv(sfd2,buf,20,MSG_WAITALL))>0){
				printf("%s",buf) ;
			}   
			if(rs<0&&errno==EAGAIN){
				continue;
			}   
			printf("over\n");
			if(rs==0 || rs<0 )
				break;
		}   
	}   

	close(sfd);    

	return 0;
}

客户端：

#include <stdio.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
typedef struct sockaddr_in sockaddr_in ;
typedef struct sockaddr sockaddr ;


int main(int argc ,char ** argv){
	sockaddr_in srv ,cli ;
	int sfd ;

	if((sfd=socket(AF_INET ,SOCK_STREAM,0))==-1){
		perror("socket error:");
		return -1 ;
	}
	if(argc < 3){
		printf("the argcs like : ./a.out ipaddr serverport ");
		return -1 ;
	}

	memset(&srv,0,sizeof(srv));
	srv.sin_port = htons(atoi(argv[2]));
	srv.sin_family = AF_INET ;
	inet_aton(argv[1],&srv.sin_addr);

	char buf[1024] ;
	int len,i ,snu,re;
	int sfd2 = connect(sfd,(sockaddr*)&srv,sizeof(sockaddr));
	if(sfd2 !=0){
		perror("");
		return -1;
	}
	while(1){
		bzero(buf,sizeof(buf));
		re = read(STDIN_FILENO ,buf,sizeof(buf));
		snu = send(sfd,buf,re-1,0);

	}
	close(sfd);
	return 0;
}