Linux上实现广播

在windows上实现广播比较简单：使用setsockopt结合SO_BROADAST即可。但是同样的代码不能在linux上获得同样的效果。

使用tcpdump监听，确实收到了广播包：

stackoverflow上的解法：

修改代码，增加 INADDR_BROADCAST一项：

#include <string>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <iostream>

int main(void)
{
    int sck = socket(AF_INET,SOCK_DGRAM,0);
    char arrRcv[1024];
    if(sck >=0){
        int iOn = 1;
        std::cout<<"join brdcst"<<setsockopt(sck, SOL_SOCKET, SO_BROADCAST, &iOn, sizeof(int))
                <<std::endl;

        struct sockaddr_in local_addr;
        memset(&local_addr, 0, sizeof(local_addr));
        local_addr.sin_family=AF_INET;
        local_addr.sin_addr.s_addr=htonl(INADDR_BROADCAST);//have to do this otherwise can't recv broadcast on linux
        local_addr.sin_port=htons(9987);
        int err = ::bind(sck,(struct sockaddr*)&local_addr,sizeof(local_addr));
        if(0 == err)
        {
            std::cout<<"bind succ"<<std::endl;
            int iRcvLen = recv(sck, arrRcv, 1024, 0);
            if(iRcvLen > 0){
                std::cout<<iRcvLen<<std::endl;
            }
        }
    }

    return 0;
}

收到数据。