devourer

README

devourer

What is this?

devourer is a tool to monitor network traffic and log network flows to BigQuery.

Usage

Prerequisites

• BigQuery dataset: You need to create a BigQuery dataset to store network flows. See here for more details.
• Service Account with BigQuery write permission: You need to create a service account with BigQuery write permission. See here for more details. You need to grant roles/bigquery.dataEditor role to the service account.
• Service Account Key: You need to create a service account key for the service account. See here for more details.

Installation

Binary

$ go install github.com/m-mizutani/devourer@latest

Docker image

$ docker pull ghcr.io/m-mizutani/devourer:latest

Run

$ devourer capture -i <interface> \
    --bq-project-id <project-id> \
    --bq-dataset <dataset-name> \
    --bq-sa-key-file <service-account-key-file>

Or you can set environment variables instead of command line options.

$ export DEVOURER_BQ_PROJECT_ID=<project-id>
$ export DEVOURER_BQ_DATASET=<dataset-name>
$ export DEVOURER_BQ_SA_KEY_FILE=<service-account-key-file>
$ devourer capture -i <interface>

How it works

devourer captures network packets and extract network flows from them. A network flow is a sequence of packets that have the same 5-tuple (source IP, destination IP, source port, destination port, protocol). devourer aggregates network flows and store them to BigQuery.

devourer does not monitor status of transport layer such as TCP, UDP, and ICMP. It only monitors network layer and application layer. So, devourer cannot detect TCP connection status such as SYN, SYN-ACK, and FIN. devourer determines closing flow by timeout. (default timeout is 120 seconds). After the timeout, devourer inserts the flow to BigQuery with flow_logs status.

Network flow schema

devourer stores network flows to BigQuery with the following schema as flow_logs table. The schema will be created automatically when you run devourer for the first time.

Column name	Type	Description
id	string	Unique ID of the network flow.
protocol	string	Protocol of the network flow.
src_addr	string	Source IP address of the network flow.
dst_addr	string	Destination IP address of the network flow.
src_port	int	Source port of the network flow.
dst_port	int	Destination port of the network flow.
first_seen_at	timestamp	Timestamp when the network flow was first seen.
last_seen_at	timestamp	Timestamp when the network flow was last seen.
src_bytes	int	Number of bytes sent from the source to the destination.
dst_bytes	int	Number of bytes sent from the destination to the source.
src_packets	int	Number of packets sent from the source to the destination.
dst_packets	int	Number of packets sent from the destination to the source.
status	string	Status of the network flow.

License

Apache License 2.0