C++通过UDP发送数据包但没有收到

Question

我目前正在做一个项目，需要每秒向公共(public)端口D88广播数据包，但客户端无法接收数据包。我不确定我是否使用正确的方式发送数据包。

int sockfdBroad;
struct sockaddr_in addrBroad;
swStat.packetBroadSent=0;

sockfdBroad=socket(AF_INET,SOCK_DGRAM,0);


bzero(&addrBroad,sizeof(addrBroad));
addrBroad.sin_family = AF_INET;
addrBroad.sin_addr.s_addr=inet_addr("192.168.1.255");
addrBroad.sin_port=htons(3464);   


if ((cycles%1000)==0)
    {

        currenttime = getMicrosTimeStamp();
        createTimePacket(bufferTime,currenttime,Odroid_Trigger);
        sendto(sockfdBroad,bufferTime,PACKET_LENGTH_TIME,0,(struct sockaddr *)&addrBroad,sizeof(addrBroad));
        swStat.packetBroadSent++;
    }

Answer 1

假设 192.168.1.255 的网络掩码是 255.255.255.0，192.168.1.255 是一个广播地址。来自 man ip(7) :

Datagrams to broadcast addresses can be only sent or received when the SO_BROADCAST socket flag is set.

换句话说，发送方和接收方都必须做:

int value = 1;
if(-1 == setsockopt(socket, SOL_SOCKET, SO_BROADCAST, &value, sizeof value))
    // Handle error.

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如果检查sendto 的返回值，它必须是-1 和errno == EACCESS。 始终检查返回值。