This package provides a Python implementation of the open Community ID flow hashing standard.
It supports Python versions 2.7+ and 3+.
The API breaks the computation into two steps: (1) creation of a flow tuple object, (2) computation of the Community ID string on this object. It supports various input types in order to accommodate network byte order representations of flow endpoints, high-level ASCII representations, etc.
In practice, it looks e.g. as follows:
import communityid
cid = communityid.CommunityID()
tpl = communityid.FlowTuple.make_tcp('127.0.0.1', '10.0.0.1', 1234, 80)
print(cid.calc(tpl))
This will print "1:mgRgpIZSu0KHDp/QrtcWZpkJpMU=".
The package includes two sample applications:
-
community-id-pcap, which iterates over a pcap via dpkt and renders Community ID values for each suitable packet in the trace. This exercices the package's "low-level" API, using flow tuple values as you'd encounter them in a typical network monitor.
-
community-id-tcpdump, which takes tcpdump output on stdin and augments it with Community ID values on stdout. This exercices the package's "high-level" API, using ASCII representations of tuple values.
The package also contains a comprehensive testsuite that can serve as reference values to verify the correctness of other implementations. See the contents of the testing/ directory for details.