Main components of the Advantech VCOM Linux Driver

The Advantech VCOM Linux Driver is composed of the following components

No.	Component Name	File Name(s)	Source code Location
1.	Linux Driver	advvcom(DKMS) or advvcom.ko(without DKMS)	driver/
2.	VCOM service daemon	vcomd	daemon/
3.	Init daemon	advttyd	init/
4.	Managment tools	advrm, advadd, advls, advman, advps, adv-eki-tls-create	scripts/ and advps/
5.	TLS related CA & key files	rootCA.key, rootCA.pem, vcom.pem	keys/Makefile
6.	VCOM mapping config file	advttyd.conf	config/
7.	TLS config file	ssl.json	config/

After installation, all of the files are copied to "/usr/local/advtty".

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Linux Driver

This is the driver that provides the "/dev/ttyADV*" tty interfaces.
Its source code is located in the "driver/" directory

VCOM service daemon

This "service daemon" connects each /dev/ttyADV* with a corresponding Device Server serial port. Eash tty is supported by a "vcomd" daemon. The source code is located in the "daemon/"

Init service daemon

This "init daemon" reads from the "VCOM mapping config file" and invokes VCOM service daemons accordingly.
the source code is located in the "init/" directory

Managment tools

This is a set of tools desinged to simplify the managment process of the "**VCOM mapping config file**", "**Linux Driver**", "**VCOM service daemon**", and "**Init daemon**".

advadd, advrm, and advls

These are bash scripts used to add, remove and list VCOM connection mappings of the VCOM mapping config file.

advman

A bash script designed to insert/remove the Linux driver, invoke/kill the VCOM service daemons.

advps

A tool designed to show the status of all the active VCOM service daemons.

adv-eki-tls-create

This bash script is designed to create files that are essential for TLS connection.
they can be used by both the EKI device server and the VCOM service daemon.
It can create "Public/Prive key pair", and "Diffie-Hellman file".

Three files are essential for creating a TLS connectoin:

1. RootCA public key
   VCOM drivers and Device servers that are connected over TLS must share the same RootCA public key.
2. Public/Private key pair
   VCOM drivers and Device servers must have their own "key pair"; however, they must be signed by the same "RootCA private key".
3. Diffie-Hellman file
   Needed by all the Device servers(TLS server) operating under TLS; however, it is not needed by the VCOM driver(TLS client).

TLS related CA & key files

A few files are created during installation, refer to the "keys/Makefile" for details on how they are created.

1. RootCA.key: This is the default RootCA private key, which is used to sign "key pairs". Keep this file private and secure.
2. RootCA.pem: This is the default RootCA public key. This file will be publicly shared by all the Device servers
3. vcom.pem: This is the default public/private key pair. Keep it private, should be accessed by this installation only.

If the VCOM driver connects to a device server, which is already operating with key files signed by another RootCA private key, one must replace these files with files created by adv-eki-tls-create, referencing the same "RootCA private key".

VCOM mapping config file

This file is read by the "init daemon"; the "init daemon" will create "VCOM service daemons" according to this configure file.

TLS config file

This file is read by the "VCOM service daemon"; it defines the location of the "RootCA public key", and "keypair file", it also defines the "password" if it ever encounters a encripted "keypair file".