【嵌入式-网络编程】vmware中使用UDP广播失败问题

问题描述：
自己在vmware中搭建了2台虚拟机，虚拟机A向虚拟机A和虚拟机B发送广播信息，接收端在虚拟机A和虚拟机B，这个时候，由于没配置sin.sin_addr.s_addr = htonl(INADDR_ANY);，而是配置的inet_pton(AF_INET, SERV_IP, &sin.sin_addr.s_addr);，导致虚拟机A的广播信号发出去了，但是虚拟机B和虚拟机A完全收不到UDP广播数据。

要点：

在发送端配置
// 设置允许广播数据
int b_br = 1;
setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &b_br, sizeof(int));
在接收端配置
sin.sin_addr.s_addr = htonl(INADDR_ANY);绑定到任意接口

// receive.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>#define SERV_PORT 5001
#define SERV_IP "192.168.32.133"int main(int argc, char *argv[])
{int sockfd;struct sockaddr_in sin;struct in_addr sinp;char buf[BUFSIZ];// 1. 创建socketif((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0){perror("socket");exit(1);}//	int b_br = 1;
//	setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &b_br, sizeof(int));// 2. 绑定服务器sin.sin_family = AF_INET;sin.sin_port = htons(SERV_PORT);// inet_pton(AF_INET, SERV_IP, &sin.sin_addr.s_addr);sin.sin_addr.s_addr = htonl(INADDR_ANY);bzero(sin.sin_zero, 8);if(bind(sockfd, (struct sockaddr *)&sin, sizeof(sin)) < 0){perror("bind");exit(1);}// 3. 从客户端接收while(1){int recvlen = -1;struct sockaddr_in srcaddrin;char srcaddr[16];int port = -1, addrlen;recvlen = recvfrom(sockfd, buf, BUFSIZ, 0, (struct sockaddr*)&srcaddrin, &addrlen);inet_ntop(AF_INET, &srcaddrin.sin_addr.s_addr, srcaddr, sizeof(srcaddrin));port = ntohs(srcaddrin.sin_port);if(recvlen == 0) printf("Client (%s:%d) is orderly shutdown\n", srcaddr, port);else if(recvlen < 0){perror("recvfrom");break;}else {// 接收到recvlen个数据if(strncasecmp("quit", buf, 4) == 0) break;printf("Client (%s:%d) recv data len=%d, addrlen=%d from client: %s\n", srcaddr, port, recvlen, addrlen, buf);}}// 4. 处理业务// 5. 发送数据close(sockfd);return 0;
}

// sender.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>#define SERV_PORT 5001
#define SERV_IP "192.168.32.255"int main(int argc, char *argv[])
{int sockfd;struct sockaddr_in sin;struct in_addr sinp;char buf[BUFSIZ];// 1. 创建socketif((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0){perror("socket");exit(1);}// 设置允许广播数据int b_br = 1;setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &b_br, sizeof(int));// 2. 发送消息sendtosin.sin_family = AF_INET;sin.sin_port = htons(SERV_PORT);inet_pton(AF_INET, SERV_IP, &sin.sin_addr.s_addr);bzero(sin.sin_zero, 8);while(1){if(fgets(buf, BUFSIZ, stdin) == NULL){perror("fgets");continue;}sendto(sockfd, buf, BUFSIZ, 0, (struct sockaddr *)&sin, sizeof(sin));if(strncasecmp("quit", buf, 4) == 0) break;}close(sockfd);return 0;
}