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需求：
.编写一个sever接收udp广播，如果有数据接收，就回应自己mac地址；（也可添加条件发送）
.编写client用于测试；
/***** server *********/
/*------------------------------------------------------------------
- Filename : MyBroadcast.c
- CreateTime : 2018-04-12 17:00
- Author : tobiu
- Description : Broad cast from server
------------------------------------------------------------------*/
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <net/if.h>
#define PORT 7890 //port自己定义
#define MAX 255
unsigned char gwmac[6];
/*************************************
* @Function : getmac
* @param :
* mac : Storage
* @Description : get ens33 mac,可根据自己网卡名称改变
*************************************/
int getmacx(unsigned char *mac) {
struct ifreq ifreq;
int sock;
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror("create socket falied...\r\n");
return -1;
}
strcpy(ifreq.ifr_name, "ens33");
if (ioctl(sock, SIOCGIFHWADDR, &ifreq) < 0) {
perror("mac ioctl error:");
return -1;
}
memcpy(mac, ifreq.ifr_hwaddr.sa_data, 6);
//printf("%02x:%02x:%02x:%02x:%02x:%02x\n ", (unsigned char) ifreq.ifr_hwaddr.sa_data[0], (unsigned char) ifreq.ifr_hwaddr.sa_data[1], (unsigned char) ifreq.ifr_hwaddr.sa_data[2],(unsigned char) ifreq.ifr_hwaddr.sa_data[3], (unsigned char) ifreq.ifr_hwaddr.sa_data[4], (unsigned char) ifreq.ifr_hwaddr.sa_data[5]);
close(sock);
return 0;
}
int broadCast(void)
{
printf("\n\n--- BroadCast will start ---\n\n");
int sockfd,ret = 0;
socklen_t len;
char recv[1024] = {0};
struct sockaddr_in my_con;
struct sockaddr_in client;
sockfd = socket(AF_INET,SOCK_DGRAM,0);
if(sockfd < 0)
{
perror("socket error!\n");
return 1;
}
my_con.sin_family = AF_INET;
my_con.sin_port = ntohs(PORT);
my_con.sin_addr.s_addr = htonl(INADDR_ANY);//INADDR_ANY,#define INADDR_ANY ((in_addr_t) 0x00000000)
/*bind*/
if (bind(sockfd, (struct sockaddr *)&my_con, sizeof(struct sockaddr)) == -1) {
/* handle exception */
perror("Bind failed!\n");
return 1;
}
len = sizeof(struct sockaddr_in);
int size = sizeof(struct sockaddr_in);
while(1)
{
printf("---- recv data ---\n");
memset(recv,0,1024);
ret = recvfrom(sockfd,recv,MAX,0,(struct sockaddr *)&client,(socklen_t*)&size);
recv[ret] = '\0';
if(ret < 0)
{
printf("no data\n");
continue;
}
printf("You got a message (%s) from %s\n",recv,inet_ntoa(client.sin_addr) );
/* get local mac */
memset(gwmac, 0, 6);
if (getmacx(gwmac) == -1) {
printf("read mac failed-----------\r\n");
return 1;
} else {
printf("read mac successed-----------\r\n");
}
int i;
printf("I will send mac : ");
for(i=0;i<6;i++)
{
printf("%02x:",gwmac[i]);
}
printf("\n");
char qbuf[40];
memset(qbuf,0,40);
sprintf(qbuf,"%02x:%02x:%02x:%02x:%02x:%02x",gwmac[0],gwmac[1],gwmac[2],gwmac[3],gwmac[4],gwmac[5]);
printf("qbuf : %s\n",qbuf);
sendto(sockfd,qbuf,strlen(qbuf),0,(struct sockaddr *)&client,len);
}
close(sockfd);
return 1;
}
int main(int argc, char const *argv[])
{
/* code */
broadCast();
return 0;
}/* client */
/*------------------------------------------------------------------
- Filename : Udpclient.c
- CreateTime : 2018-04-12 17:00
- Author : tobiu
- Description : Broad cast from client
------------------------------------------------------------------*/
#include <time.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> /* netbd.h is needed for struct hostent =) */
#define PORT 7890 /* Open Port on Remote Host */
#define MAXDATASIZE 100 /* Max number of bytes of data */
/*
udp广播通信，执行时需要两个参数如下：
./client 192.168.1.255
这样便会对192.168.1这个网段内所有开着./server的主机发送数据
*/
int main(int argc, char *argv[])
{
int fd, numbytes; /* files descriptors */
char recvbuf[MAXDATASIZE]; /* buf will store received text */
char sendbuf[MAXDATASIZE];
struct hostent *he; /* structure that will get information about remote host */
struct sockaddr_in server,client; /* server's address information */
int yes;
/* this is used because our program will need two argument (IP address and a message） */
if (argc !=2) {
printf("Usage: %s <IP Address> \n",argv[0]);
exit(1);
}
if ((he=gethostbyname(argv[1]))==NULL){ // calls gethostbyname()
printf("gethostbyname() error\n");
exit(1);
}
if ((fd=socket(AF_INET, SOCK_DGRAM, 0))==-1){ // calls socket()
printf("socket() error\n");
exit(1);
}
/* 设置通讯方式对广播，即本程序发送的一个消息，网络上所有主机均可以收到 */
yes = 1;
setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &yes, sizeof(yes));
bzero(&server,sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT); /* htons() is needed again */
server.sin_addr = *((struct in_addr *)he->h_addr); /*he->h_addr passes "*he"'s info to "h_addr" */
socklen_t len;
len=sizeof(struct sockaddr_in);
while (1) {
printf("input message:");
memset(recvbuf,0,MAXDATASIZE);
fgets(sendbuf,40,stdin);
sendto(fd,sendbuf,strlen(sendbuf),0,(struct sockaddr *)&server,len);
if ((numbytes=recvfrom(fd,recvbuf,MAXDATASIZE,0,(struct sockaddr *)&server,&len)) == -1){ /* calls recvfrom() */
printf("recvfrom() error\n");
exit(1);
}
recvbuf[numbytes]='\0';
int i;
printf("I will recv mac : %s\n",recvbuf);
}
close(fd); /* close fd */
} 运行结果：
