【二十三】 Linux网络编程——广播与组播

【二十三】      Linux网络编程——广播与组播

/*multicast  sender.c*/#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <string.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#define N 64typedef struct sockaddr SA;int main(int argc, char *argv[]){int sockfd;struct sockaddr_in peeraddr;char buf[N] = "This is a multicast package\n";if (argc < 3){printf("Usage : %s <ip> <port>\n", argv[0]);exit(-1);}if ((sockfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0){perror("fail to socket");exit(-1);}bzero(&peeraddr, sizeof(peeraddr));peeraddr.sin_family = PF_INET;peeraddr.sin_port = htons(atoi(argv[2]));peeraddr.sin_addr.s_addr = inet_addr(argv[1]);while ( 1 ){sendto(sockfd, buf, N, 0, (SA *)&peeraddr, sizeof(peeraddr));sleep(1);}return 0;}

/*multicast  receiver.c*/#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <string.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#define N 64typedef struct sockaddr SA;int main(int argc, char *argv[]){int sockfd;struct sockaddr_in myaddr, peeraddr;socklen_t peerlen;struct ip_mreq mreq;char buf[N];if (argc < 3){printf("Usage : %s <ip> <port>\n", argv[0]);exit(-1);}// XXX int socket(int domain, int type, int protocol);if ((sockfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0){perror("fail to socket");exit(-1);}bzero(&mreq, sizeof(mreq));mreq.imr_multiaddr.s_addr = inet_addr(argv[1]);mreq.imr_interface.s_addr = htonl(INADDR_ANY);if (setsockopt(sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0){perror("fail to setsockopt");exit(-1);}// XXX int bind(int sockfd, const struct sockaddr *addr,//              socklen_t addrlen);bzero(&myaddr, sizeof(myaddr));myaddr.sin_family = PF_INET;myaddr.sin_port = htons(atoi(argv[2]));myaddr.sin_addr.s_addr = htonl(INADDR_ANY);if (bind(sockfd, (SA *)&myaddr, sizeof(myaddr)) < 0){perror("fail to bind");exit(-1);}/*int on = 1;if (setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0){perror("fail to setsockopt");exit(-1);}*/peerlen = sizeof(peeraddr);while ( 1 ){recvfrom(sockfd, buf, N, 0, (SA *)&peeraddr, &peerlen);printf("[%s:%d] %s\n", inet_ntoa(peeraddr.sin_addr), ntohs(peeraddr.sin_port), buf);}return 0;}