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a1837

Member

Registered: 2019-04-18

Posts: 3

`iwconfig` reports `no wireless extensions.` with `prism0`

My wireless network controller:

$ lspci|grep Network
02:00.0 Network controller: Broadcom Inc. and subsidiaries BCM4312 802.11b/g LP-PHY (rev 01)

When I use `airmon-ng` to enable monitor mode I get:

$ ip link
[...]
3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DORMANT group default qlen 1000
    link/ether 00:26:82:2c:32:87 brd ff:ff:ff:ff:ff:ff
$ sudo airmon-ng start wlp2s0

Found 2 processes that could cause trouble. [...]

PHY     Interface       Driver          Chipset

phy0    wlp2s0          wl              Broadcom Inc. and subsidiaries BCM4312 802.11b/g LP-PHY (rev 01)

                (experimental wl monitor mode vif enabled for [phy0]wlp2s0 on [phy0]prism0)
$ ip link
[...]
3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DORMANT group default qlen 1000
    link/ether 00:26:82:2c:32:87 brd ff:ff:ff:ff:ff:ff
7: prism0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ieee802.11/prism 00:26:82:2c:32:87 brd ff:ff:ff:ff:ff:ff

However, iwconfig doesn't work with prism0.

$ sudo iwconfig prism0
prism0    no wireless extensions.

Currently I'm using the driver

$ pacman -Q|grep broadcom
broadcom-wl-dkms 6.30.223.271-19

although the situation is the same with `broadcom-wl`. Using `echo 1|sudo tee /proc/brcm_monitor0` instead of `airmon-ng` to enable monitor mode doesn't help either.

`airodump-ng` however appears to work with `prism0` -- it lists the correct ESSID and occasionally a WPA handshake.

More information:

If I use the `b43-firmware-classic` driver, iwconfig does work but airodump-ng doesn't show WPA handshake.

How can I solve the problem?

Last edited by a1837 (2019-04-18 06:25:41)

schard

Forum Moderator

From: Hannover

Registered: 2016-05-06

Posts: 1,975

Website

Re: `iwconfig` reports `no wireless extensions.` with `prism0`

I am no expert on WiFi, but it seems that your old b/g adapter does not support such a monitoring mode.

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Brocellous

Member

Registered: 2017-11-27

Posts: 145

Re: `iwconfig` reports `no wireless extensions.` with `prism0`

Looks to me like "No wireless extensions" is referring to no support for WEXT which is the kernel interface that iwconfig uses for its configuration. Looks like the classic firmware supports it and the dkms module does not. If you think your device should support monitor mode with the dkms module, why not try configuring it with newer tools that use nl80211, like iw?

a1837

Member

Registered: 2019-04-18

Posts: 3

Re: `iwconfig` reports `no wireless extensions.` with `prism0`

why not try configuring it with newer tools that use nl80211, like iw?

$ sudo iw dev prism0 info
command failed: No such device (-19)

It doesn't work either.

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Update: it seems like that this driver just don't allow modifying the channel for some reason. It can still capture WPA handshake, so I consider the problem solved.

Last edited by a1837 (2019-04-18 16:10:50)