Wireshark Dissector
Wireshark has support for the Ceph protocol and it will be shipped in the 1.12.1 release.
Using
To use the Wireshark dissector you must build it from git, the process is outlined in great detail in the Building and Installing section of the Wireshark Users Guide.
Developing
The Ceph dissector lives in Wireshark git at epan/dissectors/packet-ceph.c. At the top of that file there are some comments explaining how to insert new functionality or to update the encoding of existing types.
Before you start hacking on Wireshark code you should look at the doc/README.developer and doc/README.dissector documents as they explain the basics of writing dissectors. After reading those two documents you should be prepared to work on the Ceph dissector. The Wireshark developers guide also contains a lot of useful information but it is less directed and is more useful as a reference then an introduction.