[Q] Querying current SSID in NDIS 6.x

NTDEV
1

I have a LWF driver that will monitor WLAN activity over an interface. Is
there any OID support that would allow me to query the current SSID if the
interface is connected?

I know that I can monitor the status indications from the underlying WLAN
miniport (such as NDIS_STATUS_DOT11_ASSOCIATION_START) to get the SSID that
the NIC is associating with. However, if my LWF is installed after a WLAN
connection is established, I won’t be able to determine the SSID for the
connection.

I thought of using OID_DOT11_DESIRED_SSID_LIST, since the WDK says that the
OS won’t set this with more than one SSID entry. However, an IHV service
could set this with > 1 entry. Also, the OS could set it’s entry to a
wildcard SSID which isn’t helpful to me.

Any suggestions?

Thanks!

2

Is your filter bound above or below the NWIFI filter?

3

I set the FilterClass to custom in the INF file. Which brings up another
question: How can I bind below the NWIFI filter. I assume that by using
“custom”, I am bound below that filter.

“Jeffrey Tippet” wrote in message news:xxxxx@ntdev…

Is your filter bound above or below the NWIFI filter?

4

You cannot query the SSID using one of the DOT11 OIDs, as NWIFI will block those along its upper edge. I don’t know if there is a way to query this, short of going out to the usermode WLANAPIs.

How can I bind below the NWIFI filter. I assume that by using “custom”, I am bound below that filter.

“custom” would put you above NWIFI. We don’t support modifying filters that are bound below NWIFI.

A monitoring filter will get bound at every level, including the level between the miniport and NWIFI. If your filter doesn’t actually originate or modify packets or status indications, and doesn’t modify OIDs or issue new set/method OIDs; then it’s ok to bind your monitoring filter below NWIFI.

5

Thanks, Jeffrey!

Since my LWF is a modifying type, I’ll have to boot the connection
monitoring up to a user-mode process. I see how this can be done, so that’s
good.

“Jeffrey Tippet” wrote in message news:xxxxx@ntdev…

You cannot query the SSID using one of the DOT11 OIDs, as NWIFI will block
those along its upper edge. I don’t know if there is a way to query this,
short of going out to the usermode WLANAPIs.

How can I bind below the NWIFI filter. I assume that by using “custom”, I
am bound below that filter.

“custom” would put you above NWIFI. We don’t support modifying filters that
are bound below NWIFI.

A monitoring filter will get bound at every level, including the level
between the miniport and NWIFI. If your filter doesn’t actually originate
or modify packets or status indications, and doesn’t modify OIDs or issue
new set/method OIDs; then it’s ok to bind your monitoring filter below
NWIFI.