Question

已解决请关闭问题（但我真的不知道如何：/糟糕的一天）

我试图通过套接字在linux中发送广播，它总是通过两个接口传出（我有活跃的eth0和eth1，都在不同的部分），但是suddelny，它只是通过第一个出去，eth0

以下是代码：

void sendBroad(char *dstIP, char *localIP)
{
    int sock;                         /* Socket */
    struct sockaddr_in broadcastAddr; /* Broadcast address */
    int broadcastPermission;          /* Socket opt to set permission to broadcast */
    unsigned int localIPLen;       /* Length of string to broadcast */


    /* Create socket for sending/receiving datagrams */
    if ((sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
        perror("socket() failed");

    /* Set socket to allow broadcast */
    broadcastPermission = 1;
    if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (void *) &broadcastPermission, 
          sizeof(broadcastPermission)) < 0)
        perror("setsockopt() failed");

    /* Construct local address structure */
    memset(&broadcastAddr, 0, sizeof(broadcastAddr));   /* Zero out structure */
    broadcastAddr.sin_family = AF_INET;                 /* Internet address family */
    broadcastAddr.sin_addr.s_addr = inet_addr(dstIP);   /* Broadcast IP address */
    broadcastAddr.sin_port = htons(BroadcastPort);      /* Broadcast port */

    localIPLen = strlen(localIP);  /* Find length of localIP */
    int j;
    for (j=0; j<1; j++) //doesnt mean anything so far, not important
    {
         /* Broadcast localIP in datagram to clients */
         if (sendto(sock, localIP, localIPLen, 0, (struct sockaddr *) 
               &broadcastAddr, sizeof(broadcastAddr)) != localIPLen)
             perror("sendto() sent a different number of bytes than expected");


    }
}

有关此问题的任何帮助吗？

提前致谢！

Answer 1

您的代码看起来很快就能看到。问题可能出在目标IP地址中。

请问您是否意识到数据报随其源地址一起到达？您也不需要将地址放入有效负载中。您可以在其中放置更具体的内容，例如应用程序标识符。

Answer 2

只是要修复广播端口，它是混合的。代码本身没问题

通过套接字在Linux中发送广播

2 个答案: