improve device identification

[jeremyandrews]

Currently Netgrasp has three levels of detection:

1. The vendor associated with the MAC address
2. The hostname of the IP associated with the MAC address
3. A manually assigned custom name

Existing network scanning software can often find considerably more useful information about devices on the network. This ticket is to implement this functionality into Netgrasp.

[jeremyandrews]

nmap offers some useful OS detection:

• https://nmap.org/book/man-os-detection.html
• https://nmap.org/book/osdetect.html
• Python library: http://xael.org/pages/python-nmap-en.html (https://pypi.python.org/pypi/python-nmap)
• Example: https://stackoverflow.com/questions/16473379/trying-to-discover-ios-devices-on-my-network-using-python-script

[jeremyandrews]

we can also sniff and analyze dhcp packets, adding to the information we already get from arp packets:

• Python library: http://pydhcplib.tuxfamily.org/pmwiki/index.php (https://pypi.python.org/pypi/pydhcplib/0.6.2)
• Fork of above library (but also very old): https://github.com/dgvncsz0f/pydhcplib
• RFC: ftp://ftp.rfc-editor.org/in-notes/rfc2131.txt
• RFC: ftp://ftp.rfc-editor.org/in-notes/rfc2132.txt
• DHCP Fingerprint database: https://fingerbank.org (https://fingerbank.inverse.ca/api_doc)