[ClusterLabs] wireshark cannot recognize corosync packets

[cys]

Yesterday I found corosync took almost one hour to form a cluster(a 
failed node came back online).

So I captured some corosync packets, and opened the pcap file in wireshark.

But wireshark only displayed raw udp, no totem.

Wireshark version is 2.2.5. I'm sure it supports corosync totem.

corosync is 2.4.0.

And if corosync takes too long to form a cluster, how to diagnose it?

I read the logs, but could not figure it out.

Thanks.