mii-tool?
You might be able to get this information from the device using the tool mii-tool.
Example
$ sudo mii-tool -v eth0
eth0: negotiated 100baseTx-FD flow-control, link ok
product info: vendor 00:07:32, model 17 rev 2
basic mode: autonegotiation enabled
basic status: autonegotiation complete, link ok
capabilities: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
link partner: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
wpa_cli
The other tool that will likely give you this information is wpa_cli. It takes several options and you can query the running wpa_supplicant instance which is from what my research is showing, is what provides the 802.1X layer of security on top of the network connection.
I do not have access to this type of interface so could not work out an actual example but one of the commands will likely give you what you want:
$ wpa_cli status
Check the man page for wpa_cli for other options:
$ man wpa_cli
References