数据链路层停等控制协议socket编程实现

#include <iostream> #include <tchar.h> #include <winsock2.h> #include <windows.h> #include <string.h> #ifndef __ARQ_H__ #define __ARQ_H__ //停止等待协议BSC控制字符 #define STX (char)2 // 文始 #define ETX (char)3 // 文终 #define ENQ (char)5 // 询问 #define SYN (char)16 // 同步 #define EOT (char)4 // 送毕 #define ACK (char)6 // 正应答 #define NAK (char)15// 负应答 //BSC数据报文格式 #define MAXBSCLENGTH 1000 typedef struct Datagram { bool number; //0或者1 char data[MAXBSCLENGTH];//正文 char bcc; //控制字符 } BSC; #endif // 服务器端口 #define SERVER_PORT 2280 #define MAXRETRY 8 //最大重传次数 #define TIMEOUT 3000//传送传时时间 #pragma comment(lib,"ws2_32.lib")//设置link时的lib库 using namespace std; SOCKET PrimaryUDP; bool g_number = false; // 序号 char g_bcc; //返回的控制字符 char*ServerIP="127.0.0.1"; char*FilePath="C:\\source.txt"; char*FileSavePath="C:\\destination.txt"; sockaddr_in remote; HANDLE m_hEvent; void InitWinSock() // 初始化套接字 { WSADATA wsaData; if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) { cout<<"Windows sockets 2.2 startup unsuccessful"; } else{ cout << " OK ,initWinSock succeed !" << endl; } } void mksock(int type) { PrimaryUDP = socket(AF_INET, type,0); if (PrimaryUDP < 0) { cout << "create socket error"; } } void BindSock() // 绑定套接字 { sockaddr_in sin; sin.sin_addr.S_un.S_addr=INADDR_ANY; sin.sin_family = AF_INET; sin.sin_port = 0; if (bind(PrimaryUDP, (struct sockaddr*)&sin, sizeof(sin)) < 0) cout<< "bind error"; } bool ASendto() { //sockaddr_in remote; remote.sin_addr.S_un.S_addr = inet_addr(ServerIP); remote.sin_family = AF_INET; remote.sin_port =htons(SERVER_PORT); int fromlen = sizeof(remote); FILE * file;//打开文件 if((file = fopen(FilePath, "rb")) == NULL) { cout<<FilePath<<"open error"<<endl; return false; } cout<<"file open succeed"<<endl; // 设置文件指针位置 SetFilePointer(file,0, NULL, FILE_BEGIN); BSC bsc; //设为有信号 SetEvent(m_hEvent);// sets the state of the specified event object to signaled bool number = false; long dwRead = 0; bool sendComplete = false; while(!sendComplete) { // 清空数据 memset(bsc.data,0,MAXBSCLENGTH); // 当前分块的奇偶序号 bsc.number=number; // 记录当前的分块序号 g_number = bsc.number; if(!feof(file)) { bsc.bcc = SYN; int i = fread(bsc.data, sizeof(char),MAXBSCLENGTH , file); cout<<"read:"<<i<<"\tsend:"<<sizeof(bsc.data)<<endl; cout<<"帧号"<< g_number<< "当前发送窗口" << 1 << endl; dwRead+=i; } else { // 发送完毕 bsc.bcc = EOT; sendComplete = true; cout<<"send complete.send size:"<<dwRead<<endl; fclose(file); } for(int i=0 ; i< MAXRETRY;i++) { sendto(PrimaryUDP,(char*)&bsc,sizeof(bsc),0,(sockaddr*)&remote,fromlen); ResetEvent(m_hEvent); DWORD reslut = WaitForSingleObject(m_hEvent,TIMEOUT); if (reslut == WAIT_OBJECT_0) { //收到应答消息,一种是ACK,一种是NAK if (g_bcc == NAK) { if (i == MAXRETRY -1) { return false; } continue; // 继续重传 } else { //收到应答消息 break; } } else if(i == MAXRETRY-1) { cout<<"send file failed"<<endl; return false; } cout <<"帧号"<<g_number<<"发送超时了"<< endl; cout <<"帧号"<<g_number<<"send again"<< endl; } number = !number; // 开始发下一段数据 } return true; } DWORD WINAPI ARecv(LPVOID lpParam) { int sinlen = sizeof(remote); BSC buffer; int iread = 0; while (true) { iread = recvfrom(PrimaryUDP,(char*)&buffer,sizeof(buffer),0,(sockaddr*)&remote,&sinlen); // 处理ACK与NAK if (iread == SOCKET_ERROR) { continue; } // 与当前的分块序号进行比较,看是不是当前块的应答 if (buffer.number!=g_number) { continue; } if (buffer.bcc == ACK || buffer.bcc == NAK) { // 保存返回的控制字符 g_bcc = buffer.bcc; SetEvent(m_hEvent); } } return 0; } int main(int argc, _TCHAR* argv[]) { InitWinSock(); mksock(SOCK_DGRAM); BindSock(); m_hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); CreateThread(NULL, 0, ARecv, NULL, 0, NULL); if (!ASendto()){ cout<<"file send failed"<<endl; } system("pause"); return 0; } /* // receiver.cpp : 定义控制台应用程序的入口点。 // 服务器端口 #define SERVER_PORT 2280 #pragma comment(lib,"ws2_32.lib")//设置link时的lib库 using namespace std; //SOCKET PrimaryUDP; char FileSavePath[MAX_PATH]; void rInitWinSock()//初始化套接字 { WSADATA wsaData; if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) { cout<<"Windows sockets 2.2 startup unsuccessful"; } else{ cout<<"initwinsock error"<< endl; } } void rmksock(int type) { PrimaryUDP = socket(AF_INET, type,0); if (PrimaryUDP < 0) { cout<<"create socket error"; } } void rBindSock() { sockaddr_in sin; sin.sin_addr.S_un.S_addr = INADDR_ANY; sin.sin_family = AF_INET; sin.sin_port = htons(SERVER_PORT); if (bind(PrimaryUDP, (struct sockaddr*)&sin, sizeof(sin)) < 0) cout<<"bind error"; } DWORD WINAPI rARecv(LPVOID lpParam) { FILE * file = NULL; sockaddr_in remote; int sinlen = sizeof(remote); BSC buffer,bsc; bsc.header = STX;bsc.tail = ETX; memset(bsc.data, 0, MAXBSCLENGTH); int iread = 0; unsigned long dwReceived = 0; bool number = true;//发送方的数据开始发送时的序号设为0,为了判断是不是第一次一段数据,所以这里标为1 while (true) { iread= recvfrom(PrimaryUDP,(char*)&buffer,sizeof(buffer),0,(sockaddr*)&remote,&sinlen); if (SOCKET_ERROR == iread || buffer.header != STX || buffer.tail != ETX) { // 数据错误,发送负应答 cout<<"received a error data"<<endl; bsc.bcc = NAK;bsc.number=false;//number这时没有实际的意义 sendto(PrimaryUDP,(char*)&bsc,sizeof(bsc),0,(sockaddr*)&remote,sinlen); continue; } if (buffer.number == number) { // 重复收到数据,发送应答消息 cout<<"received a repeat data"<<endl; bsc.bcc = ACK; bsc.number = buffer.number; sendto(PrimaryUDP,(char*)&bsc,sizeof(bsc),0,(sockaddr*)&remote,sinlen); continue; } switch(buffer.bcc) { case ENQ: { number = !number;//准备接收下一段数据 // 文件请求 cout<<"received a file request message,filename:"<<buffer.data<<endl; // 打开文件 if(strcmp((FileSavePath+strlen(FileSavePath)-1),"\\")!=0) strcat(FileSavePath,"\\"); strcat(FileSavePath,buffer.data); if((file = fopen(FileSavePath, "ab")) == NULL) { cout<<"file open failed"<<endl; return 1; } break; } case SYN: { number = !number;// 文字发送中 int i =0; if((i=fwrite(buffer.data, sizeof(char), sizeof(buffer.data), file)) <= 0) { cout << "write failed" << endl; return 1; } dwReceived += i; cout<<"write:"<<i<<"\treceived:"<<sizeof(buffer.data)<<endl; break; } case EOT: { number = !number;// 文件发送完毕 cout<<"file received completely,save path:"<<FileSavePath<<",received size:"<<dwReceived<<endl; fclose(file); break; } default: { // 数据错误,发送负应答 bsc.bcc = NAK;bsc.number=false; sendto(PrimaryUDP,(char*)&bsc,sizeof(bsc),0,(sockaddr*)&remote,sinlen); continue; break; } } // 发送应答消息 bsc.bcc = ACK; bsc.number = buffer.number; sendto(PrimaryUDP,(char*)&bsc,sizeof(bsc),0,(sockaddr*)&remote,sinlen); } return 0; } int r_tmain(int argc, _TCHAR* argv[]) { InitWinSock();