数据报套接字——简单的回射服务器示例

 

 

 

Server

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>

#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

int __cdecl main(int argc, char **argv) 
{
	WSADATA wsaData;
	int iResult;
	SOCKET ServerSocket = INVALID_SOCKET; 
	struct addrinfo *result = NULL;
	struct addrinfo hints;
	sockaddr_in clientaddr;
	int clientlen = sizeof(clientaddr);
	int iSendResult; 
	char recvbuf[DEFAULT_BUFLEN];
	int recvbuflen = DEFAULT_BUFLEN;
	//初始化WinSock
	iResult = WSAStartup(MAKEWORD(2, 2), &wsaData); 
	if(iResult != 0) {
		printf("WSAStartup failed with error: %d\n", iResult);
		return 1;
	}
	ZeroMemory(&hints, sizeof(hints));
	//声明IPV4地址族，流式套接字，UDP协议
	hints.ai_family = AF_INET;
	hints.ai_socktype = SOCK_DGRAM;
	hints.ai_protocol = IPPROTO_UDP;
	hints.ai_flags = AI_PASSIVE;
	

	//解析服务器地址和端口号
	iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
	if(iResult != 0) {
		printf("getaddrinfo failed with error: %d\n", iResult);
		WSACleanup();
		return 1;
	}

	//为无连接的服务器创建套接字
	ServerSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
	if(ServerSocket == INVALID_SOCKET) {
		printf("socket failed with error: %ld\n", WSAGetLastError());
		freeaddrinfo(result);
		WSACleanup();
		return 1;
	}

	//为监听套接字绑定本地地址和端口号 
	iResult = bind(ServerSocket, result->ai_addr, (int)result->ai_addrlen);
	if(iResult == SOCKET_ERROR) {
		printf("bind failed with error: %d\n", WSAGetLastError());
		freeaddrinfo(result);
		closesocket(ServerSocket);
		WSACleanup();
		return 1;
	}
	freeaddrinfo(result);

	printf("UDP server starting\n");
	ZeroMemory(&clientaddr, sizeof(clientaddr));
	
	//recvfrom函数直接在参数中指定接收数据的源地址
	iResult = recvfrom(ServerSocket, recvbuf, recvbuflen, 0, (SOCKADDR*)&clientaddr, &clientlen);
	if(iResult > 0) {
		//情况1：成功接收到数据
		printf("Bytes received: %d\n", iResult);
		//将缓冲区的内容回送给客户端
		//sendto函数也是同理，在参数中指定数据要发送到的目的地址
		iSendResult = sendto(ServerSocket, recvbuf, iResult, 0, (SOCKADDR*)&clientaddr, clientlen);
		if(iSendResult == SOCKET_ERROR){
			printf("send failed with error: %d\n", WSAGetLastError());
			closesocket(ServerSocket);
			WSACleanup();
			return 1;
		}
		printf("Bytes sent: %d\n", iSendResult);
	}
	else if(iResult == 0) 
		//情况2：关闭连接
		printf("Connection closing...\n");
	else {
		//情况3：接收发生错误
		printf("recv failed with error: %d\n", WSAGetLastError());
		closesocket(ServerSocket);
		WSACleanup();
		return 1;
	}  
	//关闭套接字
	closesocket(ServerSocket);
	//释放资源
	WSACleanup();
	return 0;
}

Client

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>

#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

int __cdecl main(int argc, char **argv) 
{
	WSADATA wsaData;
	SOCKET ConnectLessSocket = INVALID_SOCKET;
	struct addrinfo *result = NULL, *ptr = NULL, hints ;
	char *sendbuf = "this is a test";
	char recvbuf[DEFAULT_BUFLEN];
	int iResult;
	int recvbuflen = DEFAULT_BUFLEN;
	if(argc != 2) {
		printf("usage: %s server-name\n", argv[0]);
		return 1;
	}

	//初始化套接字
	iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
	if(iResult != 0) {
		printf("WSAStartup failed with error: %d\n", iResult);
		return 1;
	}
	ZeroMemory(&hints, sizeof(hints));
	hints.ai_family = AF_UNSPEC;
	hints.ai_socktype = SOCK_DGRAM;
	hints.ai_protocol = IPPROTO_UDP;

	//解析服务器地址和端口号
	iResult = getaddrinfo(argv[1], DEFAULT_PORT, &hints, &result);
	if(iResult != 0) {
		printf("getaddrinfo failed with error: %d\n", iResult);
		WSACleanup();
		return 1;
	}
	//创建数据报套接字
	ConnectLessSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
	if(ConnectLessSocket == INVALID_SOCKET) {
		printf("scoket failed with error: %ld\n", WSAGetLastError());
		WSACleanup();
		return 1;
	}
	 
	//发送缓冲区中的测试数据
	iResult = sendto(ConnectLessSocket, sendbuf, (int)strlen(sendbuf), 0, result->ai_addr, (int)result->ai_addrlen);
	if(iResult == SOCKET_ERROR) {
		printf("send failed with error: %d\n", WSAGetLastError());
		closesocket(ConnectLessSocket);
		WSACleanup();
		return 1;
	}
	freeaddrinfo(result);
	printf("Bytes Sent: %ld\n", iResult);

	//接收数据 
	iResult = recvfrom(ConnectLessSocket, recvbuf, recvbuflen, 0, NULL, NULL);
	if(iResult > 0) 
		printf("Bytes received: %d\n", iResult);
	else if(iResult == 0) 
		printf("Connection closed\n");
	else 
		printf("recv failed with error: %d\n", WSAGetLastError());
	//关闭套接字
	closesocket(ConnectLessSocket);
	//释放资源
	WSACleanup();
	return 0;
}