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Re: Not seeing multicast on veth [message #39431 is a reply to message #37736]

Tue, 20 April 2010 11:32

zajdee
Messages: 2
Registered: October 2009

Junior Member

I see that noone has replied so far - I haven't found the solution either, anyways I am trying again and adding some more details:

Adding mcast address to veth interface manually does not work - is this a bug or a feature?

[host]:~ $ ip maddr add 224.0.0.18 dev veth2084066.0
ioctl: Invalid argument
[host]:~ $ ip maddr add 224.0.0.18 dev eth0.84

[host]:~ $ ip maddr show
<--cut-->
27:     eth0.84
        link  33:33:ff:41:bb:22 users 2
        link  01:00:5e:00:00:01 users 2
        link  33:33:00:00:00:01 users 2
        inet  224.0.0.1
        inet6 ff02::1:ff41:bb22
        inet6 ff02::1
<--cut-->
34:     veth2084066.0
        link  33:33:ff:4d:cd:f1
        link  01:00:5e:00:00:01
        link  33:33:00:00:00:01
        inet  224.0.0.1
        inet6 ff02::1:ff4d:cdf1
        inet6 ff02::1

Trying on an updated, custom built kernel:

[master]:~ $ uname -r
2.6.32-openvz

tcpdump on host:

13:29:44.661438 IP 10.2.84.66 > 224.0.0.22: igmp v3 report, 1 group record(s)
13:29:45.485942 IP 10.2.84.66.60990 > 10.2.34.28.123: NTPv4, Client, length 48
13:29:47.184397 IP 10.2.84.66 > 224.0.0.22: igmp v3 report, 1 group record(s)
13:30:18.202465 IP 10.2.84.66 > 224.0.0.22: igmp v3 report, 1 group record(s)
13:30:18.519178 IP 10.2.84.66.35496 > 10.2.34.3.123: NTPv4, Client, length 48
13:30:20.720397 IP 10.2.84.66 > 224.0.0.22: igmp v3 report, 1 group record(s)

tcpdump on guest:

13:29:44.661424 IP 10.2.84.66 > 224.0.0.22: igmp v3 report, 1 group record(s)
13:29:45.485942 IP 10.2.84.66.60990 > 10.2.34.28.123: NTPv4, Client, length 48
13:29:47.184397 IP 10.2.84.66 > 224.0.0.22: igmp v3 report, 1 group record(s)
13:30:00.384623 IP 10.2.84.66 > 224.0.0.18: VRRPv2, Advertisement, vrid 99, prio 0, authtype none, intvl 5s, length 36
13:30:05.687839 IP 10.2.84.66 > 224.0.0.18: VRRPv2, Advertisement, vrid 99, prio 0, authtype none, intvl 5s, length 36
13:30:11.159059 IP 10.2.84.66 > 224.0.0.18: VRRPv2, Advertisement, vrid 99, prio 0, authtype none, intvl 5s, length 36
13:30:16.526877 IP 10.2.84.66 > 224.0.0.18: VRRPv2, Advertisement, vrid 99, prio 0, authtype none, intvl 5s, length 36
13:30:18.202465 IP 10.2.84.66 > 224.0.0.22: igmp v3 report, 1 group record(s)
13:30:18.519178 IP 10.2.84.66.35496 > 10.2.34.3.123: NTPv4, Client, length 48
13:30:20.720397 IP 10.2.84.66 > 224.0.0.22: igmp v3 report, 1 group record(s)

As you can see, the igmp v3 report (join/leave) passes from guest to host (veth interface), however vrrp advertisements do not.

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