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 Jiro |
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Re: Getting Multicast to work on a VLAN interface | #3 |
Newbie  
Joined: 2012/7/9
From
Posts: 3
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Helllo,
i have some new information regarding to my problem:
It works without any issues on a Windows XP system!
BR Jiro
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| Jiro |
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Re: Getting Multicast to work on a VLAN interface | #2 |
Newbie Joined: 2012/7/9
From
Posts: 3
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Bump! I have another interesting fact about my Problem: It looks like the code is working fine on a 64 bit version of CentOS:
Linux localhost 2.6.32-220.el6.x86_64 #1 SMP Tue Dec 6 19:48:22 GMT 2011 x86_64 x86_64 x86_64 GNU/Linux
So what could i have done wrong on the other machine? BR Jiro |
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| Jiro |
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Getting Multicast to work on a VLAN interface | #1 |
Newbie Joined: 2012/7/9
From
Posts: 3
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Hello I am trying to get IP Multicast to work on a VLAN interface. My code looks like this:
int getInterfaceInfo(const char *ifc, uint32_t *ipaddr, uint8_t *mac)
{
# define MAX_IFC_SETS 16
printf("get InterfaceInfo ifc: <%s>, len: %i\n", ifc,strlen(ifc));
struct ifconf ifr_conf;
struct ifreq set[MAX_IFC_SETS];
int s;
unsigned i;
struct sockaddr_in *addr;
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0){
printf("Error Socket!\n");
return -1;
}
ifr_conf.ifc_len = sizeof(struct ifreq) * MAX_IFC_SETS;
ifr_conf.ifc_req = set;
if (ioctl(s, SIOCGIFCONF, & ifr_conf) < 0) {
printf("Error SIOCGICONF!\n");
return -1;
}
for (i = 0; i < ifr_conf.ifc_len / sizeof(struct ifreq); i++){
if ((!ifc[0] && strncmp(ifr_conf.ifc_req[i].ifr_name, "eth0", IFNAMSIZ) == 0) ||
(ifc[0] && strncmp(ifr_conf.ifc_req[i].ifr_name, ifc, IFNAMSIZ) == 0)) {
addr = (struct sockaddr_in *) & ifr_conf.ifc_req[i].ifr_addr;
*ipaddr = addr->sin_addr.s_addr;
// return interface index
printf("Our Interface: index: %i, name: %s, ip: %s\n",i,ifr_conf.ifc_req[i].ifr_name,inet_ntoa(addr->sin_addr));
// get also mac
if (ioctl(s, SIOCGIFHWADDR, &ifr_conf.ifc_req[i]) < 0)
return -1;
memcpy(mac, ifr_conf.ifc_req[i].ifr_hwaddr.sa_data, 6);
close(s);
return i;
}
}
close(s);
return -1;
}
MCPort::MCPort(const PortAddress_t mcaddr, const uint16_t port, const char *laddr) {
struct sockaddr_in ssock;
struct ip_mreq mreq;
int one = 1;
int zero = 0;
int ttl = 64;
m_port = port;
uint8_t mac[6];
// initialize
memset(&ssock, 0, sizeof(ssock));
ssock.sin_family = AF_INET;
ssock.sin_addr.s_addr = INADDR_ANY;
// create datagram socket
if ((m_sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
return;
setsockopt(m_sock, SOL_SOCKET, SO_REUSEADDR, (char *)&one, sizeof(one));
// bind to port
ssock.sin_port = htons(port);
if (bind(m_sock, (struct sockaddr *)&ssock,
sizeof(struct sockaddr_in)) < 0){
m_sock = -1;
return;
}
// to be able to receive multicast packets
memcpy(&mreq.imr_multiaddr.s_addr,&mcaddr.addr,sizeof(mreq.imr_multiaddr.s_addr));
uint32_t ipaddr;
int index = getInterfaceInfo(laddr, &ipaddr, mac);
mreq.imr_interface.s_addr = ipaddr;
if (setsockopt(m_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mreq, sizeof(mreq)) < 0) {
m_sock = -3;
return;
}
// prevent from receiving own multicast packet
if (setsockopt(m_sock, IPPROTO_IP, IP_MULTICAST_LOOP, (char *)&zero, sizeof(zero)) < 0) {
m_sock = -4;
return;
}
// to be able to send multicast packets from the right interface
struct in_addr localInterface;
localInterface.s_addr = ipaddr;
printf("sockopt ip: %s\n",inet_ntoa(localInterface));
if (setsockopt(m_sock, IPPROTO_IP, IP_MULTICAST_IF, (char*)&localInterface, sizeof(localInterface)) < 0)
{
printf("Error %i: %s\n",errno,strerror(errno));
m_sock = -6;
return;
}
}
Network configuration is as follows:
[root@localhost ~]# ifconfig
eth0 Link encap:Ethernet HWaddr 08:00:27:78:EC:49
inet addr:192.168.102.166 Bcast:192.168.103.255 Mask:255.255.254.0
inet6 addr: fe80::a00:27ff:fe78:ec49/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:827107 errors:0 dropped:0 overruns:0 frame:0
TX packets:678985 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:419623378 (400.1 MiB) TX bytes:547112945 (521.7 MiB)
eth0.57 Link encap:Ethernet HWaddr 08:00:27:78:EC:49
inet addr:11.0.0.66 Bcast:11.255.255.255 Mask:255.0.0.0
inet6 addr: fe80::a00:27ff:fe78:ec49/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:33 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:4177 (4.0 KiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Kernel Info:
[root@localhost ~]# uname -a
Linux LiveLinVM 2.6.32-220.el6.i686 #1 SMP Tue Dec 6 16:15:40 GMT 2011 i686 i686 i386 GNU/Linux
My code is called with the following parameters: mcaddr is "\xE0\x00\x00\x0a" port 200 laddr eth0 or eth0.57 What happens is this: When laddr is "eth0" all is fine and working as expected. I can receive UDP-Pakets sent to the Multicast-Address and sent UDP-Pakets go out on the correct interface When laddr is "eth0.57" the "setsockopt IP_MULTICAST_IF" call fails with EINVAL. Can anybody point me in the right direction where my mistake is? BR Jiro |
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