flow_age_stats: Added categorization based on FLOW_END_REASON

Co-authored-by: Václav Bartoš <[email protected]>

flow_age_stats/README.md

@@ -1,20 +1,27 @@
+---
 # Flow Age Stats module - README
 
 ## Description
-This module is used for making statistics about the age of incoming flow data. The statistics produced are minimal, maximal and average values of the differences between the time a flow was received and its TIME_FIRST and TIME_LAST timestamps.
+This module is used for making statistics about the age of incoming flow data. The statistics produced are minimal, maximal and average values of the differences between the time a flow was received and its TIME_FIRST and TIME_LAST timestamps. 
+
+Additionally the module can output two text files (0_time_first.txt, 0_time_last.txt) that each have a table of three columns. First is the max age of the flow (the end of bin range). Second is the percentage of flows that are in that age group. Third is the flow count. By default, the bins are 0-1s, 1s-10s, 10s-20s, ... 590s-600s, >600s. 
+
+If -e is specified, the statistis are computed separately by reason why the flow is exported (i.e. the value of the FLOW_END_REASON field). In this case, the files are named "<reason>_time_{first/last}.txt", where <reason> is the value of the FLOW_END_REASON field (0-5).
+
+Reference for FLOW_END_RESON values: https://www.iana.org/assignments/ipfix/ipfix.xhtml#ipfix-flow-end-reason
 
-Additionally, the module can output histograms of flow age distribution. These are written as two text files (time_first.txt, time_last.txt) that each have a table of three columns. First is the max age of the flow (the end of bin range). Second is the percentage of flows that are in that age group. Third is the flow count. By default, the bins are 0-1s, 1s-10s, 10s-20s, ... 590s-600s, >600s.
 
 ## Interfaces
 - Input: One UniRec interface
     - Template MUST contain fields TIME_FIRST and TIME_LAST
 - Output: None
 
 ## Parameters
-- '-t'       If specified, the module writes a file where the tables will be outputted. (Caution - the module will overwrite files labeled time_first.txt, time_last.txt)
+- '-t'       If specified the module writes a file where the tables will be outputed. (Caution - the module will overwrite files labeled *_time_first.txt, *_time_last.txt)
+- '-e'      'If specified the module creates statistics categorized based on FLOW_END_REASON.'
 
 ## Graphs
-This module also comes with a script that makes use of GNUplot to make graphs from the data that is outputted into files. You can see how the graph looks like below.
+This module also comes with a script (graphs.sh) that makes use of GNUplot to make graphs from the data that is outputed into files. You can see how the graph looks like below.
 
 ![ExampleGraph](example.png)