linux網路編程之：多播

#include <stdio.h>#include <sys/socket.h>#include <sys/types.h>#include <string.h>#include <stdlib.h>#include <arpa/inet.h>#define BUFLINE 256int main(int argc, char *argv[]){struct sockaddr_in local;int fd, n;struct ip_mreq mc;char msg[BUFLINE + 1];if(argc != 3){printf("Usage: ip port\n");return 1;}fd = socket(AF_INET, SOCK_DGRAM, 0);if(fd == -1){perror("socket()");return 1;}memset(&local, 0, sizeof(local));local.sin_port = htons(atoi(argv[2]));local.sin_addr.s_addr = htonl(INADDR_ANY);if(inet_pton(AF_INET, "192.168.30.61", &mc.imr_interface) <= 0){//my ipperror("inet_pton");return 1;}if(inet_pton(AF_INET, argv[1], &mc.imr_multiaddr) <= 0){//multi addrperror("inet_pton()");return 1;}printf("ip: %s\n", inet_ntoa(mc.imr_multiaddr));fflush(stdout);if(setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mc, sizeof(mc)) < 0){perror("setsockopt");return 1;}if(bind(fd, (struct sockaddr*)&local, sizeof(local)) == -1){perror("bind");return 1;}n = read(fd, msg, BUFLINE);if(n < 0){fprintf(stderr, "read");return 1;}else{msg[n - 1] = 0;printf("%s\n", msg);}return 0;}

運行：./mclient 224.0.4.5 123

224.0.4.5是組播地址。