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contrib-munin/plugins/wifi/wifi_signal_noise_

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#!/bin/sh
#
# Show current signal strength and noise for all connected peers of wifi devices.
# This plugin is suitable for wifi interfaces with a stable selection of peers
# (e.g. infrastructure).
# Author: Lars Kruse, devel@sumpfralle.de
# License: GPL v3 or later
#
# Requirements:
# * "iwinfo" tool (alternatively: fall back to "iw" - with incomplete data)
# * root privileges (for "iw" and "iwinfo")
#
# Magic markers
#%# capabilities=autoconf suggest
#%# family=auto
set -eu
# prefer "iwinfo" for information retrieval, if it is available
if which iwinfo >/dev/null; then
# "iwinfo" has a stable output format but is only available on openwrt
get_wifi_interfaces() { iwinfo | grep "^[a-zA-Z]" | awk '{print $1}'; }
# return MAC of peer and the signal strength
get_wifi_peers() { iwinfo "$1" assoclist | grep "^[0-9a-fA-F]" | awk '{print $1,$2}'; }
# the noise should be the same for all peers
get_wifi_noise() { iwinfo "$1" info | sed -n 's/^.* Noise: \([0-9-]\+\).*/\1/p'; }
else
# "iw" is available everywhere - but its output format is not recommended for non-humans
get_wifi_interfaces() { iw dev | awk '{ if ($1 == "Interface") print $2; }'; }
get_wifi_peers() { iw dev wlan0 station dump \
| awk '{ if ($1 == "Station") mac=$2; if (($1 == "signal") && ($2 == "avg:")) print mac,$3}'; }
# TODO: there seems to be no way to retrieve the noise level via "iw"
get_wifi_noise() { echo; }
fi
clean_fieldname() {
echo "$1" | sed 's/^\([^A-Za-z_]\)/_\1/; s/[^A-Za-z0-9_]/_/g'
}
get_ip_for_mac() {
local ip
ip=$(arp -n | grep -iw "$1$" | awk '{print $1}' | sort | head -1)
[ -n "$ip" ] && echo "$ip" && return 0
# no IP found - return MAC instead
echo "$1"
}
get_wifi_device_from_suffix() {
local suffix
local real_dev
# pick the part after the basename of the real file
suffix=$(basename "$0" | sed "s/^$(basename "$(readlink "$0")")//")
for real_dev in $(get_wifi_interfaces); do
[ "$suffix" != "$(clean_fieldname "$real_dev")" ] || echo "$real_dev"
done | head -1
}
ACTION="${1:-}"
case "$ACTION" in
config)
wifi=$(get_wifi_device_from_suffix)
echo "graph_title Wireless signal quality - $wifi"
echo "graph_args --upper-limit 0"
echo "graph_vlabel Signal and noise [dBm]"
echo "graph_category network"
echo "graph_info This graph shows the signal and noise for all wifi peers"
echo "noise.label Noise floor"
echo "noise.draw LINE"
# sub graphs for all peers
get_wifi_peers "$wifi" | while read mac signal; do
fieldname=$(clean_fieldname "peer_${mac}")
peer=$(get_ip_for_mac "$mac")
echo "signal_${fieldname}.label $peer"
echo "signal_${fieldname}.draw LINE"
done
;;
autoconf)
[ -z "$(get_wifi_interfaces)" ] && echo "no (no wifi interfaces found)" && exit 1
echo "yes"
;;
suggest)
get_wifi_interfaces | while read ifname; do
clean_fieldname "$ifname"
done
;;
"")
wifi=$(get_wifi_device_from_suffix)
peer_data=$(get_wifi_peers "$wifi")
echo "$peer_data" | while read mac signal; do
# ignore empty datasets
[ -z "$signal" ] && continue
fieldname=$(clean_fieldname "peer_${mac}")
echo "signal_${fieldname}.value $signal"
done
echo "noise.value $(get_wifi_noise "$wifi")"
;;
*)
echo >&2 "Invalid action (valid: config)"
echo >&2
;;
esac