windows C++ 通过UDP广播获取网络中所有设备ip地址

//#include "stdafx.h" #include <WinSock2.h> #include <stdio.h> #include <iostream> using namespace std; #pragma comment(lib, "ws2_32.lib") #define GET_HOST_COMMAND "GetIPAddr" const int MAX_BUF_LEN = 255; #define SERVER_PORT 12811 typedef struct tagIPInfo { char ip[30]; }IPInfo; bool GetLocalIPs(IPInfo* ips,int maxCnt,int* cnt) { //1.初始化wsa WSADATA wsaData; int ret=WSAStartup(MAKEWORD(2,2),&wsaData); if (ret!=0) { return false; } //2.获取主机名 char hostname[256]; ret=gethostname(hostname,sizeof(hostname)); if (ret==SOCKET_ERROR) { return false; } //3.获取主机ip HOSTENT* host=gethostbyname(hostname); if (host==NULL) { return false; } //4.逐个转化为char*并拷贝返回 *cnt=host->h_length<maxCnt?host->h_length:maxCnt; for (int i=0;i<*cnt;i++) { in_addr* addr=(in_addr*)*host->h_addr_list; strcpy(ips[i].ip,inet_ntoa(addr[i])); } return true; } bool GetLocalIP(char* ip) { //1.初始化wsa WSADATA wsaData; int ret=WSAStartup(MAKEWORD(2,2),&wsaData); if (ret!=0) { return false; } //2.获取主机名 char hostname[256]; ret=gethostname(hostname,sizeof(hostname)); if (ret==SOCKET_ERROR) { return false; } //3.获取主机ip HOSTENT* host=gethostbyname(hostname); if (host==NULL) { return false; } //4.转化为char*并拷贝返回 strcpy(ip,inet_ntoa(*(in_addr*)*host->h_addr_list)); return true; } bool doServer(){ int m_nPort = SERVER_PORT; SOCKET sClient; sockaddr_in clientAddr,bindAddr; WSADATA wsdata; //启动SOCKET库，版本为2.0 WORD wVer=MAKEWORD(2,0); if( 0 != WSAStartup(wVer,&wsdata) ) { //AfxMessageBox(L"Not Support Socket2.0"); return false; } //用UDP初始化套接字 sClient=socket(AF_INET,SOCK_DGRAM,0); //设置该套接字为广播类型， BOOL optval=TRUE; bindAddr.sin_family=AF_INET; bindAddr.sin_addr.s_addr=htonl(INADDR_ANY); bindAddr.sin_port=htons(m_nPort); setsockopt(sClient,SOL_SOCKET,SO_BROADCAST,(char FAR *)&optval,sizeof(optval)); bind(sClient,(sockaddr *)&bindAddr,sizeof(sockaddr_in)); int nAddrLen = sizeof(SOCKADDR); char buf[256] = {0}; int fromlength=sizeof(SOCKADDR); printf("the server is start.\n"); char ipaddr[30] = {0}; char buff[MAX_BUF_LEN] = ""; if (GetLocalIP(ipaddr)) { sprintf(buff, "my ip is:%s", ipaddr); } else { sprintf(buff, "%s", "my ip is:******"); } //有多个ip地址的时候 //IPInfo ips[10]; //int len1 = 0; //GetLocalIPs(ips, 10,&len1); while(true) { int nRet = recvfrom(sClient,buf,256,0,(struct sockaddr FAR *)&clientAddr,(int FAR *)&fromlength); if( SOCKET_ERROR != nRet ) { char *pIPAddr = inet_ntoa(clientAddr.sin_addr); if( NULL != pIPAddr ) { WCHAR wzIPBuffer[32] = {0}; //CXAStrToWide(pIPAddr, wzIPBuffer, 32); //AfxMessageBox(wzIPBuffer); printf("clientAddr: %s\n", pIPAddr); printf("receive command: %s\n", buf); } if (strcmp(buf,GET_HOST_COMMAND) != 0) { printf("the command not valid and was ignored.\n", buf); continue; } // 发送数据 int nSendSize = sendto(sClient, buff, strlen(buff), 0, (SOCKADDR*)&clientAddr, nAddrLen); if(SOCKET_ERROR == nSendSize) { int err = WSAGetLastError(); printf("\"sendto\" error!, error code is %d\n", err); return false; } } else { //AfxMessageBox(L"Recv UDP Failed"); } Sleep(1000); } closesocket(sClient); return true; } int main() { if (!doServer()) { printf("sever returned an error"); return -1; } return 0; } /* int main() { WORD wVersionRequested; WSADATA wsaData; int err; // 启动socket api wVersionRequested = MAKEWORD( 2, 2 ); err = WSAStartup( wVersionRequested, &wsaData ); if ( err != 0 ) { return -1; } if ( LOBYTE( wsaData.wVersion ) != 2 || HIBYTE( wsaData.wVersion ) != 2 ) { WSACleanup( ); return -1; } // 创建socket SOCKET connect_socket; connect_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if(INVALID_SOCKET == connect_socket) { err = WSAGetLastError(); printf("\"socket\" error! error code is %d\n", err); return -1; } SOCKADDR_IN sin; sin.sin_family = AF_INET; sin.sin_port = htons(3779); sin.sin_addr.s_addr = INADDR_BROADCAST; bool bOpt = true; //设置该套接字为广播类型 setsockopt(connect_socket, SOL_SOCKET, SO_BROADCAST, (char*)&bOpt, sizeof(bOpt)); int nAddrLen = sizeof(SOCKADDR); char buff[MAX_BUF_LEN] = ""; int nLoop = 0; while(1) { nLoop++; sprintf(buff, "%8d", nLoop); // 发送数据 int nSendSize = sendto(connect_socket, buff, strlen(buff), 0, (SOCKADDR*)&sin, nAddrLen); if(SOCKET_ERROR == nSendSize) { err = WSAGetLastError(); printf("\"sendto\" error!, error code is %d\n", err); return -1; } printf("Send: %s\n", buff); Sleep(500); } return 0; } */