[英]Problem in listening to multicast in C++ with multiple NICs
你好
我想寫一台機器上的多播客戶端兩個網卡,我不能使它發揮作用。
我用嗅探器看到,一旦啟動程序,NIC(eth4)就開始接收多播數據報,但是,程序中我什么也收不到。
運行“ tshark -i eth4 -R udp.port == xxx(多播端口)”時
我得到:
1059.435483 YYYY(有些IP) - > ZZZZ(IP組播,不是我的ETH4網卡的IP),UDP源端口:KKK(一些其他的端口)目標端口:XXX(多播端口)
搜索一些例子/解釋網頁,但好像我做什么其他人一樣。
任何幫助將不勝感激...
謝謝!
bool connectionManager::sendMulticastJoinRequest()
{
struct sockaddr_in localSock;
struct ip_mreqn group;
char* mc_addr_str = SystemManager::Instance()->getTCP_IP_CHT();
char* local_addr_str = SystemManager::Instance()->getlocal_IP_TOLA();
int port = SystemManager::Instance()->getTCP_Port_CHT();
/* Create a datagram socket on which to receive. */
CHT_UDP_Feed_sock = socket(AF_INET, SOCK_DGRAM, 0);
if(CHT_UDP_Feed_sock < 0)
{
perror("Opening datagram socket error");
return false;
}
/* application to receive copies of the multicast datagrams. */
{
int reuse = 1;
if(setsockopt(CHT_UDP_Feed_sock, SOL_SOCKET, SO_REUSEADDR, (char *)&reuse, sizeof(reuse)) < 0)
{
perror("Setting SO_REUSEADDR error");
close(CHT_UDP_Feed_sock);
return false;
}
}
/* Bind to the proper port number with the IP address */
/* specified as INADDR_ANY. */
memset((char *) &localSock, 0, sizeof(localSock));
localSock.sin_family = AF_INET;
localSock.sin_port = htons(port);
localSock.sin_addr.s_addr =inet_addr(local_addr_str); // htonl(INADDR_ANY); //
if(bind(CHT_UDP_Feed_sock, (struct sockaddr*)&localSock, sizeof(localSock)))
{
perror("Binding datagram socket error");
close(CHT_UDP_Feed_sock);
return false;
}
/* Join the multicast group mc_addr_str on the local local_addr_str */
/* interface. Note that this IP_ADD_MEMBERSHIP option must be */
/* called for each local interface over which the multicast */
/* datagrams are to be received. */
group.imr_ifindex = if_nametoindex("eth4");
if (setsockopt(CHT_UDP_Feed_sock, SOL_SOCKET, SO_BINDTODEVICE, "eth4", 5) < 0)
return false;
group.imr_multiaddr.s_addr = inet_addr(mc_addr_str);
group.imr_address.s_addr = htonl(INADDR_ANY); //also tried inet_addr(local_addr_str); instead
if(setsockopt(CHT_UDP_Feed_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&group, sizeof(group)) < 0)
{
perror("Adding multicast group error");
close(CHT_UDP_Feed_sock);
return false;
}
// Read from the socket.
char databuf[1024];
int datalen = sizeof(databuf);
if(read(CHT_UDP_Feed_sock, databuf, datalen) < 0)
{
perror("Reading datagram message error");
close(CHT_UDP_Feed_sock);
return false;
}
else
{
printf("Reading datagram message...OK.\n");
printf("The message from multicast server is: \"%s\"\n", databuf);
}
return true;
}
在調用IP_ADD_MEMBERSHIP之前,請像下面這樣設置組 :
group.imr_multiaddr.s_addr = inet_addr(mc_addr_str);
group.imr_address.s_addr = inet_addr(local_addr_str);
您可以在此之前保留對SO_BINDTODEVICE的調用,但這僅在您只想使用一個特定接口的情況下才需要。
我完全按照這樣設置組(更新了代碼)。
我還將添加到路由表“ route add -net 224.0.0.0 netmask 240.0.0.0 dev eth4”
仍然沒有成功。
除此之外,我還需要在環境中設置其他任何內容嗎?
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