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* Unable to receive multicast stream
@ 2006-04-20 17:38 Andrew Athan
  2006-04-20 19:10 ` David S. Miller
  2006-04-20 20:47 ` linux-os (Dick Johnson)
  0 siblings, 2 replies; 3+ messages in thread
From: Andrew Athan @ 2006-04-20 17:38 UTC (permalink / raw)
  To: linux-kernel


The simple UDP multicast receive application below, adapted from source 
on IBM's web site, will not receive any data.  While it is blocked on 
recv():

hfclinux2:/home/root/UDP/apps/Crosser2# netstat -ang
IPv6/IPv4 Group Memberships
Interface       RefCnt Group
--------------- ------ ---------------------
lo              1      224.0.0.1
eth0            1      224.0.0.1
eth1            1      224.0.17.44
eth1            1      224.0.0.1
lo              1      ff02::1
eth0            1      ff02::1:ffdd:eb2b
eth0            1      ff02::1
eth1            1      ff02::1:ffdd:eb2c
eth1            1      ff02::1


And tcpdump shows traffic arriving at the interface(see below)!  This 
leads me to belive the kernel is filtering it, and or not delivering it 
to the socket.

The one "strange" thing about this network is that the traffic is 
flowing in "dense mode", meaning there is no explicit need for IGMP 
messaging (nor any response to such messaging).

Can anyone point me in the right direction regarding why the socket 
never receives any data????

Thanks.
Andrew

hfclinux2:/home/root/UDP/apps/Crosser2# uname -a
Linux hfclinux2 2.6.15.1smp #6 SMP PREEMPT Mon Feb 13 11:38:32 EST 2006 
i686 GNU/Linux

hfclinux2:/home/root/UDP/apps/Crosser2# tcpdump -i eth1 port 55300
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
12:54:06.980000 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 91
12:54:07.079675 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 46
12:54:07.179869 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 181
12:54:07.280437 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 181
12:54:07.380005 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 181
12:54:07.480073 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 136
12:54:07.680459 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 91
12:54:07.780277 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 136


hfclinux2:/home/root/UDP/apps/Crosser2# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2B
          inet addr:172.22.71.128  Bcast:172.22.71.255  Mask:255.255.255.0
          inet6 addr: fe80::211:43ff:fedd:eb2b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:19540 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7838 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1563190 (1.4 MiB)  TX bytes:1943895 (1.8 MiB)
          Base address:0xdcc0 Memory:dfae0000-dfb00000

eth0:1    Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2B
          inet addr:10.61.6.128  Bcast:10.61.6.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Base address:0xdcc0 Memory:dfae0000-dfb00000

eth0:2    Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2B
          inet addr:196.0.34.11  Bcast:196.0.34.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Base address:0xdcc0 Memory:dfae0000-dfb00000

eth0:3    Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2B
          inet addr:192.168.254.128  Bcast:192.168.254.255  
Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Base address:0xdcc0 Memory:dfae0000-dfb00000

eth1      Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2C
          inet addr:192.168.250.128  Bcast:192.168.250.255  
Mask:255.255.255.0
          inet6 addr: fe80::211:43ff:fedd:eb2c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:137717 errors:0 dropped:0 overruns:0 frame:0
          TX packets:24 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:58314262 (55.6 MiB)  TX bytes:1596 (1.5 KiB)
          Base address:0xccc0 Memory:df8e0000-df900000

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)



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

using namespace std;


struct sockaddr_in    localSock;
struct ip_mreqn        group;
int                   sd;
int                   datalen;
char                  databuf[10];

int main (int argc, char *argv[])
{
  sd = socket(AF_INET, SOCK_DGRAM, 0);
  if (sd < 0) {
    perror("opening datagram socket");
    exit(1);
  }

  {
    int reuse=1;

    if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR,
                   (char *)&reuse, sizeof(reuse)) < 0) {
      perror("setting SO_REUSEADDR");
      close(sd);
      exit(1);
    }
  }

  memset((char *) &localSock, 0, sizeof(localSock));
  localSock.sin_family = AF_INET;
  localSock.sin_port = htons(55300);;
  localSock.sin_addr.s_addr  = INADDR_ANY;

  if (bind(sd, (struct sockaddr*)&localSock, sizeof(localSock))) {
    perror("binding datagram socket");
    close(sd);
    exit(1);
  }


  group.imr_multiaddr.s_addr = inet_addr("224.0.17.44");
  printf("%d\n",group.imr_multiaddr.s_addr);
  group.imr_address.s_addr = inet_addr("192.168.250.128");
  if (setsockopt(sd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                 (char *)&group, sizeof(group)) < 0) {
    perror("adding multicast group");
    close(sd);
    exit(1);
  }
  /*
   * Read from the socket.
   */
  datalen = sizeof(databuf);
  if (read(sd, databuf, datalen) < 0) {
    perror("reading datagram message");
    close(sd);
    exit(1);
  } else {
    puts("success reading");
  }
 }



^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Unable to receive multicast stream
  2006-04-20 17:38 Unable to receive multicast stream Andrew Athan
@ 2006-04-20 19:10 ` David S. Miller
  2006-04-20 20:47 ` linux-os (Dick Johnson)
  1 sibling, 0 replies; 3+ messages in thread
From: David S. Miller @ 2006-04-20 19:10 UTC (permalink / raw)
  To: aathan_linux_kernel_1542; +Cc: linux-kernel


You'll have better luck with your query on netdev@vger.kernel.org
which is where all the networking developers hang out.

Thanks.

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Unable to receive multicast stream
  2006-04-20 17:38 Unable to receive multicast stream Andrew Athan
  2006-04-20 19:10 ` David S. Miller
@ 2006-04-20 20:47 ` linux-os (Dick Johnson)
  1 sibling, 0 replies; 3+ messages in thread
From: linux-os (Dick Johnson) @ 2006-04-20 20:47 UTC (permalink / raw)
  To: Andrew Athan; +Cc: linux-kernel


On Thu, 20 Apr 2006, Andrew Athan wrote:

>
> The simple UDP multicast receive application below, adapted from source
> on IBM's web site, will not receive any data.  While it is blocked on
> recv():
>
> hfclinux2:/home/root/UDP/apps/Crosser2# netstat -ang
> IPv6/IPv4 Group Memberships
> Interface       RefCnt Group
> --------------- ------ ---------------------
> lo              1      224.0.0.1
> eth0            1      224.0.0.1
> eth1            1      224.0.17.44
> eth1            1      224.0.0.1
> lo              1      ff02::1
> eth0            1      ff02::1:ffdd:eb2b
> eth0            1      ff02::1
> eth1            1      ff02::1:ffdd:eb2c
> eth1            1      ff02::1
>
>
> And tcpdump shows traffic arriving at the interface(see below)!  This
> leads me to belive the kernel is filtering it, and or not delivering it
> to the socket.
>
> The one "strange" thing about this network is that the traffic is
> flowing in "dense mode", meaning there is no explicit need for IGMP
> messaging (nor any response to such messaging).
>
> Can anyone point me in the right direction regarding why the socket
> never receives any data????
>
> Thanks.
> Andrew
>
> hfclinux2:/home/root/UDP/apps/Crosser2# uname -a
> Linux hfclinux2 2.6.15.1smp #6 SMP PREEMPT Mon Feb 13 11:38:32 EST 2006
> i686 GNU/Linux
>
> hfclinux2:/home/root/UDP/apps/Crosser2# tcpdump -i eth1 port 55300
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
> 12:54:06.980000 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 91
> 12:54:07.079675 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 46
> 12:54:07.179869 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 181
> 12:54:07.280437 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 181
> 12:54:07.380005 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 181
> 12:54:07.480073 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 136
> 12:54:07.680459 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 91
> 12:54:07.780277 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 136
>
>
> hfclinux2:/home/root/UDP/apps/Crosser2# ifconfig
> eth0      Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2B
>          inet addr:172.22.71.128  Bcast:172.22.71.255  Mask:255.255.255.0
>          inet6 addr: fe80::211:43ff:fedd:eb2b/64 Scope:Link
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          RX packets:19540 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:7838 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:1000
>          RX bytes:1563190 (1.4 MiB)  TX bytes:1943895 (1.8 MiB)
>          Base address:0xdcc0 Memory:dfae0000-dfb00000
>
> eth0:1    Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2B
>          inet addr:10.61.6.128  Bcast:10.61.6.255  Mask:255.255.255.0
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          Base address:0xdcc0 Memory:dfae0000-dfb00000
>
> eth0:2    Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2B
>          inet addr:196.0.34.11  Bcast:196.0.34.255  Mask:255.255.255.0
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          Base address:0xdcc0 Memory:dfae0000-dfb00000
>
> eth0:3    Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2B
>          inet addr:192.168.254.128  Bcast:192.168.254.255
> Mask:255.255.255.0
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          Base address:0xdcc0 Memory:dfae0000-dfb00000
>
> eth1      Link encap:Ethernet  HWaddr 00:11:43:DD:EB:2C
>          inet addr:192.168.250.128  Bcast:192.168.250.255
> Mask:255.255.255.0
>          inet6 addr: fe80::211:43ff:fedd:eb2c/64 Scope:Link
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          RX packets:137717 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:24 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:1000
>          RX bytes:58314262 (55.6 MiB)  TX bytes:1596 (1.5 KiB)
>          Base address:0xccc0 Memory:df8e0000-df900000
>
> 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)
>
>
>
> -------------------------
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <arpa/inet.h>
> #include <netinet/in.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <unistd.h>
> #include <string.h>
>
> using namespace std;
>
>
> struct sockaddr_in    localSock;
> struct ip_mreqn        group;
> int                   sd;
> int                   datalen;
> char                  databuf[10];
>
> int main (int argc, char *argv[])
> {
>  sd = socket(AF_INET, SOCK_DGRAM, 0);
>  if (sd < 0) {
>    perror("opening datagram socket");
>    exit(1);
>  }
>
>  {
>    int reuse=1;
>
>    if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR,
>                   (char *)&reuse, sizeof(reuse)) < 0) {
>      perror("setting SO_REUSEADDR");
>      close(sd);
>      exit(1);
>    }
>  }
>
>  memset((char *) &localSock, 0, sizeof(localSock));
>  localSock.sin_family = AF_INET;
>  localSock.sin_port = htons(55300);;
>  localSock.sin_addr.s_addr  = INADDR_ANY;
>
>  if (bind(sd, (struct sockaddr*)&localSock, sizeof(localSock))) {
>    perror("binding datagram socket");
>    close(sd);
>    exit(1);
>  }
>
>
>  group.imr_multiaddr.s_addr = inet_addr("224.0.17.44");
>  printf("%d\n",group.imr_multiaddr.s_addr);
>  group.imr_address.s_addr = inet_addr("192.168.250.128");
>  if (setsockopt(sd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
>                 (char *)&group, sizeof(group)) < 0) {
>    perror("adding multicast group");
>    close(sd);
>    exit(1);
>  }
>  /*
>   * Read from the socket.
>   */
>  datalen = sizeof(databuf);
>  if (read(sd, databuf, datalen) < 0) {
>    perror("reading datagram message");
>    close(sd);
>    exit(1);
>  } else {
>    puts("success reading");
>  }
> }


12:54:07.780277 IP 206.200.5.144.2232 > 224.0.17.44.55300: UDP, length 136
                                                            ^^^___ datagram

Question? Don't you need to use:

     socklen_t slen = sizeof(localSock);
     recvfrom(sd, databuf, datalen, &localSock, &slen);

... to receive a datagram?

Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.4 on an i686 machine (5592.89 BogoMips).
Warning : 98.36% of all statistics are fiction, book release in April.
_
\x1a\x04

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^ permalink raw reply	[flat|nested] 3+ messages in thread

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