Tom Jones

Fortnightly Transport Call Meeting Notes

Email: <thj AT SPAMFREE freebsd DOT org>

Hacking Notes

Loader

building:

make buildenv
make -C stand

pcie pass through

The old method for having ppt pick up devices is with loader.conf like:

Instead we can use devctl which will take a device name or a path. If we detach we need to use a fuller device path. I.e.:

sudo devctl detach xhci0
sudo devctl set driver pci0:0:20:0 ppt

Wireless

Some handy wireshark expressions:

probe

    request and response
        (wlan.sa == e4:5e:37:dc:12:6b  or wlan.ra == e4:5e:37:dc:12:6b ) and (wlan.fc.type_subtype == 0x0004 or wlan.fc.type_subtype == 0x0005)
assoc
    request and response
        (wlan.sa == e4:5e:37:dc:12:6b  or wlan.ra == e4:5e:37:dc:12:6b ) and (wlan.fc.type_subtype == 0x0004 or wlan.fc.type_subtype == 0x0005)

The in operator makes it easier to compare with a list.

wlan.fc.type_subtype in {0x0000, 0x0001, 0x0004, 0x0005}

        (wlan.sa == e4:5e:37:dc:12:6b  or wlan.ra == e4:5e:37:dc:12:6b )

Decrypting wpa with tshark

sudo tcpdump -i wlan1 -y IEEE802_11_RADIO
sudo tshark -i wlan1 -I -V  -o wlan.enable_decryption:TRUE -o "uat:80211_keys:\"wpa-pwd\",\"{ieee80211}:{fw-enc}\""
sudo tshark -i wlan1 -I -V  -o wlan.enable_decryption:TRUE -o 'uat:80211_keys:"wpa-pwd","{ieee80211}:{fw-enc}"' -Y 'wlan.sa == e4:5e:37:dc:12:6b  or wlan.ra == e4:5e:37:dc:12:6b'

Streaming from the air interface on an OpenWRT router

on the openwrt side we need:

        root@OpenWrt:~# tcpdump -i phy0-mon0 --immediate-mode -U -w - | nc -l -p 19000

We can filter for the gl.inet router with:

        root@OpenWrt:~# tcpdump -i phy0-mon0 --immediate-mode -U ether host 94:83:c4:98:ab:f2 or ether host e4:5e:37:dc:12:6b -w - | nc -l -p 19000
or for a specific pair of hosts:
        tcpdump -i phy0-mon0 --immediate-mode -U ether host 94:83:c4:98:ab:f2 or ether host e4:5e:37:dc:12:6b or type ctl subtype ack -w - | nc -l -p 19000

as a script:

        staeth="ether 94:83:c4:98:ab:f2"
        apeth="ether host e4:5e:37:dc:12:6b"
        ack="type ctl subtype ack"
        beacon="subtype beacon"

        tcpdump -i phy0-mon0 --immediate-mode -U -w - \
                "($staeth or $apeth or $ack) and (not $beacon)" | nc -l -p 19000

Wireshark can now connect to my remote host (192.168.4.34 as an example):

        $ wireshark -k -i TCP@192.168.4.164:19000

Getting OpenWRT to advertise 160MHz channels

root@OpenWrt:~# cat /etc/config/wireless 

config wifi-device 'radio0'
        option type 'mac80211'
        option path 'platform/soc/18000000.wifi'
        option band '2g'
        option channel '6'
        option htmode 'HE20'
        option num_global_macaddr '7'
        option disabled '0'
        option country 'GB'
        option log_level '2'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'a2-enc'
        option encryption 'psk2'
        option key 'ieee80211'

config wifi-device 'radio1'
        option type 'mac80211'
        option path 'platform/soc/18000000.wifi+1'
        option band '5g'
        option channel '36'
        option htmode 'VHT160'
#       option htmode 'HE80'
        option num_global_macaddr '7'
        option disabled '0'
        option country 'GB'
        option background_radar '0'
        option log_level '1'

config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'ap'
        option ssid 'a5-enc'
        option encryption 'psk2'
        option key 'ieee80211'

Building stuff

build with gcc

make CROSS_TOOLCHAIN=amd64-gcc14 buildkernel

Bugs

Free bugs, fixes and usability things for anyone that needs one

nextboot

$ nextboot -k kernel.m6
error: 1
nextboot: zfsbootcfg returned 1: No error: 0
$ sudo nextboot -k kernel.m6

Should be permission denied

python3 cannot send on divert sockets

# kldload ipdivert
# sudo ipfw add 200 divert 42 tcp from any to 192.168.1.1 2600 (divert doesn't work on localhost)

#create a raw socket

import sys
import socket

ruleport = ("0.0.0.0", 42)

sock = socket.socket(socket.PF_DIVERT, socket.SOCK_RAW, 0)
sock.bind(ruleport)


while True:
    print("reading from socket")

    buf = sock.recv(65565)      # should be recvfrom
    sockto.sendto(buf, port)    # should be sendto


    print("got a packet {} bytes".format(len(buf)))

This throws an exception for the method not being supported by the protocol family

ifconfig should parse all arguments before performing opeations

$ sudo ifconfig wlan create wlandev rtwn0 wlanmmode monitor
Password:
ifconfig: wlanmmode: bad value
wlan1

This shouldn't have created wlan1, which has now been created in the wrong mode (the default station)

Installer

The installer should be modal, we should be asking questions and then performing actions. A user should be able to do all their work upfront and then the machine should do the machining.
Installler should tell the user they can remove the usb stick
We should be able to remove the usb stick immediately if it doesn't contain images.

pkgbase

now we have base we should ship a minimal wpa_supplicant.conf

Small things

vidfont shouldn't exit when a font is picked
vidfont should output the sysrc command to set this for all screens
wpa_supplicant should default to bsd, wlan0 and /etc/wpa_supplicant.conf

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