From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Sat, 11 Jan 2014 13:31:13 +0100
Subject: package/base-files: change sysctl handling

Add hotplug script that applies interface specific sysctls for interfaces that
only appear later - this allows to reliably configure per-interface parameters
in sysctl.conf, e.g. to disable ipv6 autoconfig on a specific iface.

Cherry-picked from Barrier Breaker

diff --git a/package/base-files/files/etc/hotplug.d/net/00-sysctl b/package/base-files/files/etc/hotplug.d/net/00-sysctl
new file mode 100644
index 0000000..5d9da8a
--- /dev/null
+++ b/package/base-files/files/etc/hotplug.d/net/00-sysctl
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+if [ -f /etc/sysctl.conf ] && [ "$ACTION" = add ]; then
+	sed -ne "/^[[:space:]]*net\..*\.$DEVICENAME\./p" /etc/sysctl.conf | \
+		sysctl -e -p - | logger -t sysctl
+fi