多播包的发送与接收

来源：互联网发布：mac压缩包密码破解编辑：程序博客网时间：2024/06/14 07:44
Listener Program#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <time.h>#include <string.h>#include <stdio.h>#define HELLO_PORT 12345#define HELLO_GROUP "225.0.0.37"#define MSGBUFSIZE 256main(int argc, char *argv[]){     struct sockaddr_in addr;     int fd, nbytes,addrlen;     struct ip_mreq mreq;     char msgbuf[MSGBUFSIZE];     u_int yes=1;     /* create what looks like an ordinary UDP socket */     if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {          perror("socket");          exit(1);     }    /* allow multiple sockets to use the same PORT number */    if (setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(yes)) < 0) {       perror("Reusing ADDR failed");       exit(1);       }     /* set up destination address */     memset(&addr,0,sizeof(addr));     addr.sin_family=AF_INET;     addr.sin_addr.s_addr=htonl(INADDR_ANY); /* N.B.: differs from sender */     addr.sin_port=htons(HELLO_PORT);          /* bind to receive address */     if (bind(fd,(struct sockaddr *) &addr,sizeof(addr)) < 0) {          perror("bind");          exit(1);     }          /* use setsockopt() to request that the kernel join a multicast group */     mreq.imr_multiaddr.s_addr=inet_addr(HELLO_GROUP);     mreq.imr_interface.s_addr=htonl(INADDR_ANY);     if (setsockopt(fd,IPPROTO_IP,IP_ADD_MEMBERSHIP,&mreq,sizeof(mreq)) < 0) {          perror("setsockopt");          exit(1);     }     /* now just enter a read-print loop */     while (1) {          addrlen=sizeof(addr);          if ((nbytes=recvfrom(fd,msgbuf,MSGBUFSIZE,0,                               (struct sockaddr *) &addr,&addrlen)) < 0) {               perror("recvfrom");               exit(1);          }          puts(msgbuf);     }}#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <time.h>#include <string.h>#include <stdio.h>#define HELLO_PORT 12345#define HELLO_GROUP "225.0.0.37"main(int argc, char *argv[]){     struct sockaddr_in addr;     int fd, cnt;     struct ip_mreq mreq;     char message[16]="Hello, World!";     /* create what looks like an ordinary UDP socket */     if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {          perror("socket");          exit(1);     }     /* set up destination address */     memset(&addr,0,sizeof(addr));     addr.sin_family=AF_INET;     addr.sin_addr.s_addr=inet_addr(HELLO_GROUP);     addr.sin_port=htons(HELLO_PORT);          /* now just sendto() our destination! */     while (1) {          if (sendto(fd,message,sizeof(message),0,(struct sockaddr *) &addr,                     sizeof(addr)) < 0) {               perror("sendto");               exit(1);          }          sleep(1);     }}
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