Socket基础三：基于流式套接字的网络程序（服务器回射程序设计)

作者：刘磊 2020.4.27

参考书目：《Windows网络编程》刘琰等著

• 回射程序

回射程序是进行网络诊断的常用工具之一，例如Ping是windows系统下自带的可执行命令，利用它可以检查网络是否连通，不过ping是网络层上的，不适合传输层的应用程序测试和诊断。

• 基本执行步骤

服务器：

1. 引用头文件
2. 创建流式套接字
3. 捆绑服务器的指定端口到套接字
4. 把套接字变换成监听套接字
5. 接收客户连接
6. 接收客户发来的数据
7. 发送客户发来的数据
8. 回到步骤6
9. 如果客户端关闭连接，则终止当前连接
10. 回到步骤5
11. 如果终止条件到，则关闭套接字，释放资源，关闭程序。

客户机：

1. 引用头文件
2. 处理命令行参数
3. 创建流式套接字
4. 指定服务器IP地址和端口
5. 与服务器建立连接
6. 获得用户输入
7. 发送回射请求
8. 接收并输出服务器应答
9. 回到步骤6
10. 如果终止条件到，则关闭套接字，释放资源，终止程序

• 对回射功能进行编码

1）tcp_server_fun_echo(SOCKET s)编程代码如下：

[code]//回射函数int tcp_server_fun_echo(SOCKET s){int iResult = 0;char recvline[MAXLINE];do {memset(recvline, 0, MAXLINE);//接收数据iResult = recv(s, recvline, MAXLINE, 0);if (iResult > 0){printf(\"服务器接收到数据%s\\n\", recvline);//回射发送已收到的数据iResult = send( s, recvline, iResult, 0);if (iResult == SOCKET_ERROR){printf(\"send 函数调用错误，错误号：%d\\n\", WSAGetLastError());return 1;}elseprintf(\"对方连接关闭，退出\\n\");}else{if (iResult == 0)printf(\"对方连接关闭，退出\\n\");else{printf(\"recv 函数调用错误，错误号：%d\\n\", WSAGetLastError());return 1;}break;}} while (iResult > 0);return iResult;}

2）tcp_client_fun_echo(FILE *fp,SOCKET s)编程代码如下：

[code]//回射函数int tcp_client_fun_echo(FILE *fp, SOCKET s){int iResult;char sendline[MAXLINE], recvline[MAXLINE];memset(sendline, 0, MAXLINE);memset(recvline, 0, MAXLINE);while (fgets(sendline, MAXLINE, fp) != NULL){if (*sendline == \'Q\'){printf(\"input end!\\n\");iResult = shutdown(s, SD_SEND);if (iResult == SOCKET_ERROR){printf(\"shutdown failed with error:%d\\n\", WSAGetLastError());}return 0;}iResult = send(s, sendline, strlen(sendline), 0);if (iResult == SOCKET_ERROR){printf(\"send 函数调用错误，错误号：%d\\n\", WSAGetLastError());return 1;}printf(\"\\r\\n客户端发送数据：%s\\r\\n\", sendline);memset(recvline,0,MAXLINE);iResult = recv(s,recvline,MAXLINE,0);if (iResult > 0)printf(\"客户端接收到数据 %s \\r\\n\",recvline);else{if (iResult == 0)printf(\"服务器终止！\\n\");elseprintf(\"recv 函数调用错误，错误号：%d\\n\", WSAGetLastError());break;}memset(sendline, 0, MAXLINE);}return iResult;}

• 主函数

1、server.c

[code]#include \"mysocket.h\"#define ECHOPORT \"7210\"int main(int argc, char *argv[]){int iResult = 0;char ip[] = \"127.0.0.1\";SOCKET ListenSocket, ConnetSocket;start_up();ListenSocket = tcp_server( ip, ECHOPORT);if (ListenSocket == -1)return 1;printf(\"服务器准备好回射服务......\\n\");for (; ; ){ConnetSocket = accept(ListenSocket, NULL, NULL);if (ConnetSocket != INVALID_SOCKET){printf(\"\\r\\n建立连接成功\\n\\n\");iResult = tcp_server_fun_echo(ConnetSocket);if (iResult == -1)printf(\"当前连接已关闭或出错\\n\");}else{printf(\"accept 函数调用错误，错误号:%d\\n\",WSAGetLastError());quit(ListenSocket);return 1;}if(closesocket(ConnetSocket) == SOCKET_ERROR)printf(\"closesocket 函数调用错误，错误号:%d\\n\", WSAGetLastError());}quit(ListenSocket);return 0;}

2、client.c

[code]#include \"mysocket.h\"#define ECHOPORT \"7210\"int main(int argc, char *argv[]){int iResult = 0;SOCKET ClientSocket;start_up();printf(\"连接建立成功，请输入回射字符串......\\n\");ClientSocket = tcp_client((char *)argv[1], ECHOPORT);if (ClientSocket == -1)return 1;iResult = tcp_client_fun_echo(stdin,ClientSocket);quit(ClientSocket);return iResult;}

3、mysocket.h

[code]#pragma once#include <time.h>#include <winsock2.h>#include <stdio.h>#pragma comment(lib,\"ws2_32.lib\");using namespace std;#define MAXLINE 4096	//接收缓冲区长度#define LISTENQ 1024	//监听队列长度#define SERVER_PORT 13	//时间同步服务器端口号int start_up(void);		//初始化Windows Sockets DLL；协商版本号int clean_up(void);		//windows sockets资源释放函数int set_address(char *hname, char * sname, struct sockaddr_in * sap, char * protocol);		//地址转换函数int quit(SOCKET s);		//退出处理函数SOCKET tcp_server(char *hname, char *sname);		//服务器初始化函数（字符类型）SOCKET tcp_server(ULONG uIP, USHORT uPort);			//服务器初始化函数（无符号长整型）SOCKET tcp_client(char *hname, char *sname);		//客户端初始化函数（字符类型）SOCKET tcp_client(ULONG uIP, USHORT uPort);			//客户端初始化函数（无符号长整型）int tcp_server_fun_echo(SOCKET s);		//回射函数int tcp_client_fun_echo(FILE *fp,SOCKET s);		//回射函数

4、mysocket.c

[code]#include \"mysocket.h\"//初始化Windows Sockets DLL；协商版本号int start_up(void){//初始化Windows Sockets DLL；协商版本号WORD wVersionRequested;WSADATA wsaData;int iResult;//使用MAKEWORD(lowbyte, highbyte) 宏，在windef.h中声明wVersionRequested = MAKEWORD(2, 2);iResult = WSAStartup(wVersionRequested, &wsaData);if (iResult != 0){printf(\"WSAStartup函数调用错误，错误号：%d\\n\", WSAGetLastError());return -1;}else{printf(\"初始化成功！\\n\");}return 0;}//windows sockets资源释放函数int clean_up(void){int iResult;iResult = WSACleanup();if (iResult == SOCKET_ERROR){printf(\" WSACleanup函数调用错误，错误号：%d\\n\", WSAGetLastError());return 1;}elseprintf(\"WSACleanup 函数调用错误，错误号：%d\\n\", WSAGetLastError());return 0;}//地址转换函数int set_address(char *hname, char * sname, struct sockaddr_in * sap, char * protocol){struct servent *sp;struct hostent *hp;char *endptr;unsigned short port;unsigned long ulAddr = INADDR_NONE;//将地址结构socketaddr_in初始化为0，并设置地址为AF_INETmemset( sap, 0, sizeof( *sp));sap->sin_family = AF_INET;if (hname != NULL){//如果hname不为空，假定给出的hname为点分十进制表示的数字地址，转换地址为sockaddr_in类型ulAddr = inet_addr(hname);if (ulAddr == INADDR_NONE || ulAddr == INADDR_ANY){//调用错误，表明给出的是主机名，调用gethostbyname获得主机地址hp = gethostbyname(hname);if (hp = NULL){printf(\"未知的主机名，错误号：%d\\n\", WSAGetLastError());return -1;}sap->sin_addr = *(struct in_addr *)hp->h_addr;}elsesap->sin_addr.S_un.S_addr = ulAddr;}elsesap->sin_addr.s_addr = htonl(INADDR_ANY);port = (unsigned short)strtol(sname, &endptr, 0);if (*endptr == \'\\0\'){sap->sin_port = htons(port);}else{sp = getservbyname(sname, protocol);if (sp == NULL){printf(\"未知的服务，错误号;%d\\n\",WSAGetLastError());return -1;}sap->sin_port = sp->s_port;}return 0;}//退出处理函数int quit(SOCKET s){int iResult = 0;iResult = closesocket(s);if (iResult == SOCKET_ERROR){printf(\"closesocket 函数调用错误，错误号：%d\\n\", WSAGetLastError());return -1;}iResult = clean_up();return iResult;}//服务器初始化函数（字符类型）SOCKET tcp_server(char *hname, char *sname){sockaddr_in local;SOCKET ListenSocket;const int on = 1;int iResult = 0;//为服务器的本地地址local设置用户输入的IP和端口号if (set_address(hname, sname, &local, \"tcp\") != 0)return -1;//创建套接字ListenSocket = socket(AF_INET, SOCK_STREAM, 0);if (ListenSocket == INVALID_SOCKET){printf(\"socket函数调用错误，错误号：%d\\n\",WSAGetLastError());clean_up();return -1;}//绑定服务器地址iResult = bind(ListenSocket, (struct sockaddr *) & local, sizeof(local));if (iResult == SOCKET_ERROR){printf(\"bind 函数调用错误，错误号：%d\\n\", WSAGetLastError());quit(ListenSocket);return -1;}//设置服务器位监听状态，监听队列长度为LISTENQiResult = listen(ListenSocket, SOMAXCONN);if (iResult == SOCKET_ERROR){printf(\"listen 函数调用错误，错误号：%d\\n\", WSAGetLastError());quit(ListenSocket);return -1;}return ListenSocket;}//服务器初始化函数（无符号长整型）SOCKET tcp_server(ULONG uIP, USHORT uPort){sockaddr_in local;SOCKET ListenSocket;const int on = 1;int iResult = 0;//为服务器的本地地址local设置用户输入的IP和端口号memset(&local, 0, sizeof(local));local.sin_family = AF_INET;local.sin_addr.S_un.S_addr = htonl(uIP);local.sin_port = htons(uPort);//创建套接字ListenSocket = socket(AF_INET, SOCK_STREAM, 0);if (ListenSocket == INVALID_SOCKET){printf(\"socket函数调用错误，错误号：%d\\n\", WSAGetLastError());clean_up();return -1;}//绑定服务器地址iResult = bind(ListenSocket, (struct sockaddr *) & local, sizeof(local));if (iResult == SOCKET_ERROR){printf(\"bind 函数调用错误，错误号：%d\\n\", WSAGetLastError());quit(ListenSocket);return -1;}//设置服务器位监听状态，监听队列长度为LISTENQiResult = listen(ListenSocket, SOMAXCONN);if (iResult == SOCKET_ERROR){printf(\"listen 函数调用错误，错误号：%d\\n\", WSAGetLastError());quit(ListenSocket);return -1;}return ListenSocket;}//客户端初始化函数（字符类型）SOCKET tcp_client(char *hname, char *sname){struct sockaddr_in peer;SOCKET ClientSocket;int iResult = 0;//为服务器的本地地址local设置用户输入的IP和端口号if (set_address(hname, sname, &peer, \"tcp\") != 0)return -1;//创建套接字ClientSocket = socket(AF_INET, SOCK_STREAM, 0);if (ClientSocket == INVALID_SOCKET){printf(\"socket函数调用错误，错误号：%d\\n\", WSAGetLastError());clean_up();return -1;}//绑定服务器地址iResult = connect(ClientSocket, (struct sockaddr *) & peer, sizeof(peer));if (iResult == SOCKET_ERROR){printf(\"bind 函数调用错误，错误号：%d\\n\", WSAGetLastError());quit(ClientSocket);return -1;}return ClientSocket;}//客户端初始化函数（无符号长整型）SOCKET tcp_client(ULONG uIP, USHORT uPort){struct sockaddr_in peer;SOCKET ClientSocket;int iResult = 0;//为服务器的本地地址local设置用户输入的IP和端口号memset(&peer, 0, sizeof(peer));peer.sin_family = AF_INET;peer.sin_addr.S_un.S_addr = htonl(uIP);peer.sin_port = htons(uPort);//创建套接字ClientSocket = socket(AF_INET, SOCK_STREAM, 0);if (ClientSocket == INVALID_SOCKET){printf(\"socket函数调用错误，错误号：%d\\n\", WSAGetLastError());clean_up();return -1;}//绑定服务器地址iResult = connect(ClientSocket, (struct sockaddr *) & peer, sizeof(peer));if (iResult == SOCKET_ERROR){printf(\"bind 函数调用错误，错误号：%d\\n\", WSAGetLastError());quit(ClientSocket);return -1;}return ClientSocket;}//回射函数int tcp_server_fun_echo(SOCKET s){int iResult = 0;char recvline[MAXLINE];do {memset(recvline, 0, MAXLINE);//接收数据iResult = recv(s, recvline, MAXLINE, 0);if (iResult > 0){printf(\"服务器接收到数据%s\\n\", recvline);//回射发送已收到的数据iResult = send( s, recvline, iResult, 0);if (iResult == SOCKET_ERROR){printf(\"send 函数调用错误，错误号：%d\\n\", WSAGetLastError());return -1;}elseprintf(\"对方连接关闭，退出\\n\");}else{if (iResult == 0)printf(\"对方连接关闭，退出\\n\");else{printf(\"recv 函数调用错误，错误号：%d\\n\", WSAGetLastError());return -1;}break;}} while (iResult > 0);return iResult;}//回射函数int tcp_client_fun_echo(FILE *fp, SOCKET s){int iResult;char sendline[MAXLINE], recvline[MAXLINE];memset(sendline, 0, MAXLINE);memset(recvline, 0, MAXLINE);while (fgets(sendline, MAXLINE, fp) != NULL){if (*sendline == \'Q\'){printf(\"input end!\\n\");iResult = shutdown(s, SD_SEND);if (iResult == SOCKET_ERROR){printf(\"shutdown failed with error:%d\\n\", WSAGetLastError());}return 0;}iResult = send(s, sendline, strlen(sendline), 0);if (iResult == SOCKET_ERROR){printf(\"send 函数调用错误，错误号：%d\\n\", WSAGetLastError());return -1;}printf(\"\\r\\n客户端发送数据：%s\\r\\n\", sendline);memset(recvline,0,MAXLINE);iResult = recv(s,recvline,MAXLINE,0);if (iResult > 0)printf(\"客户端接收到数据 %s \\r\\n\",recvline);else{if (iResult == 0)printf(\"服务器终止！\\n\");elseprintf(\"recv 函数调用错误，错误号：%d\\n\", WSAGetLastError());break;}memset(sendline, 0, MAXLINE);}return iResult;}//工作线程完成了在特定连接上接收客户端数据，并将数据发回的功能，直到客户端关闭连接或网络操作发生错误UINT tcp_server_fun_echo(LPVOID pParam){int iResult = 0;char recvline[MAXLINE];int err;//将输入参数转换为连接套接字SOCKET s = *((SOCKET *)pParam);do {memset(recvline, 0, MAXLINE);//接收数据iResult = recv(s, recvline, MAXLINE, 0);if (iResult > 0){printf(\"服务器接收到数据: %s\\n\",recvline);//回射发送已收到的数据iResult = send(s, recvline, MAXLINE, 0);if (iResult == SOCKET_ERROR){printf(\"send 函数调用错误，错误号：%d\\n\", WSAGetLastError());err = closesocket(s);if(err == SOCKET_ERROR)printf(\"closesocket 函数调用错误，错误号：%d\\n\", WSAGetLastError());iResult = -1;}elseprintf(\"服务器发送数据: %s\\n\", recvline);}else{if (iResult == 0)printf(\"对方连接关闭，退出\\n\");else{printf(\"recv 函数调用错误，错误号：%d\\n\", WSAGetLastError());iResult = -1;}err = closesocket(s);if (err == SOCKET_ERROR)printf(\"closesocket 函数调用错误，错误号：%d\\n\", WSAGetLastError());break;}} while (iResult > 0);return iResult;}