From: Dan Williams <dcbw@redhat.com>
To: Thomas Thielemann <thomas@th-thielemann.de>,
linux-wireless@vger.kernel.org
Subject: Re: How to use netlink to determine wifi protection WEP
Date: Wed, 05 Apr 2017 12:24:47 -0500 [thread overview]
Message-ID: <1491413087.14498.2.camel@redhat.com> (raw)
In-Reply-To: <163FFAFB-1BA3-42A1-9F84-0EAEDFEBE5AE@th-thielemann.de>
On Wed, 2017-04-05 at 09:27 +0200, Thomas Thielemann wrote:
> Hello!
>
> I need a solution to determine whether a WiFi is using WEP. I know
> there is a protection flag within MAC frame but do not know how to
> access.
>
> To detect whether a WiFi i protected by WPA2 I found the following
> solution:
>
> Scan with
>
> nl_sock* socket = nl_socket_alloc();
> genl_connect(socket);
> struct nl_msg* msg = nlmsg_alloc();
> int driverId = genl_ctrl_resolve(socket, "nl80211");
> genlmsg_put(msg, 0, 0, driverId, 0, 0, NL80211_CMD_TRIGGER_SCAN, 0);
>
> and fetch with
>
> genlmsg_put(msg, 0, 0, driverId, 0, NLM_F_DUMP, NL80211_CMD_GET_SCAN,
> 0);
>
> Read the received structure using nl80211_bss::
> NL80211_BSS_INFORMATION_ELEMENTS from nl80211.h and
>
> examine the field RSN(id=48) (see IEEE802.11-2012.pdf, chapter 8.4.2
> Information elements)
>
> Which netlink command gives me the related data? Is it
> NL80211_CMD_GET_BEACON?
You want both the beacon (for the Privacy bit) and the information
elements.
If the privacy bit is set in beacon and there are no WPA/WPA2/RSN-
related information elements, then the AP is using WEP. Unfortunately
you don't know whether it's WEP-40 or WEP-104, but that's another
topic.
If the privacy bit is set, and there are WPA/WPA2/RSN information
elements, then the AP *might* be using WEP in compatibility mode. This
isn't very common though, so you can probably just ignore this case.
Dan
next prev parent reply other threads:[~2017-04-05 17:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 7:27 How to use netlink to determine wifi protection WEP Thomas Thielemann
2017-04-05 17:24 ` Dan Williams [this message]
2017-04-06 14:27 ` Thomas Thielemann
2017-04-06 15:41 ` Dan Williams
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