d4-goclient/README.md

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**d4-goclient** is a D4 project client (sensor) implementing the [D4 encapsulation protocol](https://github.com/D4-project/architecture/tree/master/format).

The client can be used on different targets and architectures to collect network capture, logs, specific network monitoring and send it
back to a [D4 server](https://github.com/D4-project/d4-core).

For more information about the [D4 project](https://www.d4-project.org/).

# Installation

Fetch d4-goclient code and dependencies

```bash
go get github.com/satori/go.uuid
go get github.com/D4-project/d4-goclient
```

Use make to build binaries:

```bash
make arm5l  # for raspberry pi / linux
make amd64l # for amd64 / linux
```

## Dependencies

 - golang 1.10 (tested)
 - go.uuid

# Use

## Launch a d4-server (if you don't have a server)

See https://github.com/D4-project/d4-core/tree/master/server
$IP_SRV being the d4-server's address, $PORT its listening port

## Configuration files
Part of the client configuration can be stored in folder containing the following files:

 - key: your Pre-Shared-Key
 - snaplen: default is 4096
 - source: stdin
 - destination: stdout, [fe80::ffff:ffff:ffff:a6fb]:4443, 127.0.0.1:4443
 - type: D4 packat type, see [types](https://github.com/D4-project/architecture/tree/master/format)
 - uuid: generated automiatically if empty
 - version: protocol version
 - rootCA.crt: optional CA certificate to check the server certificate

## Flags

```bash
  -c string
    	configuration directory
  -cc
    	Check TLS certificate against rootCA.crt
  -ce
    	Set to True, true, TRUE, 1, or t to enable TLS on network destination (default true)
  -cka duration
    	Keep Alive time human format, 0 to disable (default 30s)
  -ct duration
    	Set timeout in human format
  -rt duration
    	Time in human format before retry after connection failure, set to 0 to exit on failure (default 30s)
  -v	Set to True, true, TRUE, 1, or t to enable verbose output on stdout
```

## Pipe data into the client
In the followin examples, destination is set to stdout.

### Some file
```bash
cat /proc/cpuinfo | ./d4-goclient -c conf.sample/ |  socat - OPENSSL-CONNECT:$IP_SRV:$PORT,verify=0
```

### tcpdump (libpcap) output, discarding our own traffic
$IP being the monitoring computer ip
```bash
tcpdump not dst $IP and not src $IP -w - | ./d4-goclient -c conf.sample/ |  socat - OPENSSL-CONNECT:$IP_SRV:$PORT,verify=0
```