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https://github.com/JamesonHuang/OpenWrt_Luci_Lua.git
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103 lines
3.6 KiB
C++
103 lines
3.6 KiB
C++
/*************************************************************************
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> File Name: socket_client.cpp
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> Description:
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> Conclusion:
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> Author: rh_Jameson
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> Created Time: 2015年05月21日 星期四 16时19分58秒
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************************************************************************/
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#include<stdio.h>
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#include<stdlib.h>
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#include<unistd.h>
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#include<string.h>
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#include<sys/socket.h>
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#include<arpa/inet.h>
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#include<netinet/in.h>
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#include<sys/types.h>
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#include<netdb.h>
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#include <sys/ioctl.h>
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#include <net/if.h>
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/**
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客户端实现广播
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**/
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#define IP_FOUND "sysinfo"
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#define IP_FOUND_ACK "IP_FOUND_ACK"
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#define IFNAME "wlan2"
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#define MCAST_PORT 51232
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int main(int argc,char*argv[]){
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int ret=-1;
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int sock=-1;
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int so_broadcast=1;
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struct ifreq ifr;
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struct sockaddr_in broadcast_addr;//广播地址
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struct sockaddr_in from_addr;//服务端地址
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socklen_t from_len=sizeof(from_addr);
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int count=-1;
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fd_set readfd;//读文件描述符集合
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char buffer[1024];
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struct timeval timeout;
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timeout.tv_sec=2;//超时时间为2秒
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timeout.tv_usec=0;
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sock=socket(AF_INET,SOCK_DGRAM,0);//建立数据报套接字
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if(sock<0){
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printf("HandleIPFound:sock init error\n");
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return 0;
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}
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//将使用的网络接口名字复制到ifr.ifr_name中，由于不同的网卡接口的广播地址是不一样的，因此指定网卡接口
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strncpy(ifr.ifr_name,IFNAME,strlen(IFNAME));
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//发送命令，获得网络接口的广播地址
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if(ioctl(sock,SIOCGIFBRDADDR,&ifr)==-1){
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perror("ioctl error");
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return 0;
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}
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//将获得的广播地址复制到broadcast_addr
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memcpy(&broadcast_addr,&ifr.ifr_broadaddr,sizeof(struct sockaddr_in));
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//设置广播端口号
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//inet_aton("255.255.255.255", &broadcast_addr.sin_addr);
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printf("broadcast IP is:%s\n",inet_ntoa(broadcast_addr.sin_addr));
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broadcast_addr.sin_family=AF_INET;
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broadcast_addr.sin_port=htons(MCAST_PORT);
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//默认的套接字描述符sock是不支持广播，必须设置套接字描述符以支持广播
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ret=setsockopt(sock,SOL_SOCKET,SO_BROADCAST,&so_broadcast,sizeof(so_broadcast));
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//发送多次广播，看网络上是否有服务器存在
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int times=10;
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int i=0;
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for(i = 0; i < times; i++){//一共发送10次广播，每次等待2秒是否有回应
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//广播发送服务器地址请求
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timeout.tv_sec = 2;//超时时间为2秒
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timeout.tv_usec = 0;
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ret=sendto(sock,IP_FOUND, strlen(IP_FOUND), 0, (struct sockaddr*)&broadcast_addr, sizeof(broadcast_addr));
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if(ret == -1){
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continue;
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}
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//文件描述符清0
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FD_ZERO(&readfd);
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//将套接字文件描述符加入到文件描述符集合中
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FD_SET(sock,&readfd);
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//select侦听是否有数据到来
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ret=select(sock+1,&readfd,NULL,NULL,&timeout);
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switch(ret){
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case -1:
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break;
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case 0:
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printf("timeout\n");
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break;
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default:
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//接收到数据
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if(FD_ISSET(sock,&readfd)){
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count = recvfrom(sock, buffer, 1024, 0, (struct sockaddr*)&from_addr,&from_len);//from_addr为服务器端地址
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printf("recvmsg is %s\n", buffer);
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if(strstr(buffer, IP_FOUND_ACK)){
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printf("found server IP is:%s\n",inet_ntoa(from_addr.sin_addr));
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//服务器端的发送端口号
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printf("Server Port:%d\n",htons(from_addr.sin_port));
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}
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return 0;
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}
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break;
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}
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}
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return 0;
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}
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