From 53135f5f5d187a04075ac724c03c08d5dc672dc0 Mon Sep 17 00:00:00 2001
From: Lars Kruse <devel@sumpfralle.de>
Date: Sun, 12 Jun 2016 02:51:52 +0200
Subject: [PATCH] network: new wifi_signal_noise_ plugin for signal strength
 and noise

This new plugin offers the following advantages compared to the existing wifi_signal plugin:
* support multiple wifi peers (e.g. mesh mode or master mode with multiple clients)
* use "iwinfo" or "iw" for information retrieval (instead of Linux's procfs)
---
 plugins/network/wifi_signal_noise_ | 108 +++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100755 plugins/network/wifi_signal_noise_

diff --git a/plugins/network/wifi_signal_noise_ b/plugins/network/wifi_signal_noise_
new file mode 100755
index 00000000..e4c2b946
--- /dev/null
+++ b/plugins/network/wifi_signal_noise_
@@ -0,0 +1,108 @@
+#!/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