UDP下的广播、组播（多播）-VC6

#include <stdio.h> #include<Winsock2.h> #include<string.h> #define SOCKETPORT 7788 #define LOOPCOUNT 10 #pragma comment(lib,"ws2_32.lib") void main() { WORD wVersionRequested;//存放请求的WS2_32.DLL版本 WSADATA wsaData;//指针，用于存放windows socket执行详细信息 int err, i; SOCKET sockSrv; SOCKADDR_IN addrSrv;//internet地址结构体 SOCKADDR_IN addrDest; int len; char sendbuffer[100]; BOOL bFlag; int nIP_TTL; //IP数据报的TTL值 DWORD cbRet; char buffer[20]; len=sizeof(SOCKADDR);//地址名长度 //设置windows中socket的Dll文件版本 wVersionRequested = MAKEWORD(2,2); err = WSAStartup( wVersionRequested, &wsaData ); if ( err != 0 ) { printf("WSAStartup error!\n"); return; } //请求的版本如果与想要的不一样，则清理socket后退出。 if ( LOBYTE( wsaData.wVersion ) != 2 || HIBYTE( wsaData.wVersion ) != 2 ) { WSACleanup(); return; } //创建一个组播socket，internet地址类型，stream表示TCP连接/dgram表示UDP连接 sockSrv = WSASocket(AF_INET, SOCK_DGRAM, IPPROTO_UDP, (LPWSAPROTOCOL_INFO)NULL, 0, WSA_FLAG_OVERLAPPED | WSA_FLAG_MULTIPOINT_C_LEAF | WSA_FLAG_MULTIPOINT_D_LEAF); //设置socket选项，允许重用本地地址和端口 bFlag = 1; setsockopt(sockSrv,SOL_SOCKET, SO_REUSEADDR, (char *)&bFlag, sizeof(bFlag)); //填写服务器端socket地址结构 addrSrv.sin_addr.S_un.S_addr=htonl(INADDR_ANY);//主机序转换为网络序，IP地址为任意（任意本地可用地址）。 //addrSrv.sin_addr.S_un.S_addr=inet_addr("127.0.0.1"); addrSrv.sin_family=AF_INET; addrSrv.sin_port=htons(SOCKETPORT);//socket端口 bind(sockSrv,(SOCKADDR*)&addrSrv,sizeof(SOCKADDR));//绑定socket和地址名 if(WSAGetLastError() != 0) { printf("bind error!\n"); return; } //设置套接口工作方式，将IP数据报的TTL值设定为1 nIP_TTL = 10; WSAIoctl(sockSrv,SIO_MULTICAST_SCOPE,&nIP_TTL,sizeof(nIP_TTL),NULL,0,&cbRet,NULL,NULL); if(WSAGetLastError() != 0) { printf("WSAIoctl error!\n"); return; } //设置套接口工作方式，允许内部回送 bFlag = TRUE; WSAIoctl(sockSrv, SIO_MULTIPOINT_LOOPBACK, &bFlag,sizeof(bFlag),NULL,0,&cbRet,NULL,NULL); if(WSAGetLastError() != 0) { printf("WSAIoctl error!\n"); return; } //填写接收端socket地址结构（组播地址） addrDest.sin_addr.S_un.S_addr=inet_addr("224.1.1.1");//组播地址 addrDest.sin_family = PF_INET; addrDest.sin_port=htons(SOCKETPORT);//socket端口 if(WSAGetLastError() != 0) { printf("WSAHtons error!\n"); return; } for ( i=0; i<LOOPCOUNT; i++) { //组播发送 sprintf(sendbuffer, "This is No.%s message.(Group 224.1.1.1)", itoa(i, buffer, 10)); sendto(sockSrv, sendbuffer, 100, 0, (SOCKADDR *)&addrDest, sizeof(SOCKADDR)); err = WSAGetLastError(); if(err != 0) { printf("sendto error: %d!\n", err); break; } } addrDest.sin_addr.S_un.S_addr=inet_addr("224.1.1.2");//组播地址 for ( i=0; i<LOOPCOUNT; i++) { //组播发送 sprintf(sendbuffer, "This is No.%s message.(Group 224.1.1.2)", itoa(i, buffer, 10)); sendto(sockSrv, sendbuffer, 100, 0, (SOCKADDR *)&addrDest, sizeof(SOCKADDR)); err = WSAGetLastError(); if(err != 0) { printf("sendto error: %d!\n", err); break; } } closesocket(sockSrv); if(WSACleanup() != 0) { printf("Windows socket cleanup failed!\n"); } }