batman-adv: Split batadv proto in meshif and hardif part

batman-adv: Split batadv proto in meshif and hardif part

batman-adv allows to configure three different objects:

* batadv hardif

  - network interface used by batadv meshif to transport the batman-adv
    packets
  - its master interface is set to the batadv meshif

* batadv (meshif/softif)

  - virtual interface that emulates a normal 802.3 interface on top
  - encapsulates traffic and forwards it via the batadv hardifs

* batadv vlan

  - potential VLAN ID on top of batadv meshif
  - allows filtering of traffic from specific VIDs

While batadv vlan objects were already represented as an own proto
"batadv_vlan", the batadv meshif could never be fully configured using
/etc/config/network. Instead, parts of its configuration were stored in
/etc/config/batman_adv and some in the interfaces with the "batadv" proto.

To increase the confusion, the "batadv" proto wasn't used to define the
batadv meshif but to identify batadv (slave) hardifs. The batman-adv
meshifs were also never created directly but only when a hardif was
configured. The actual modification of the configuration settings was then
applied using a hotplug script hack. The batadv meshif network interface
could therefore only be created when an hardif was available and not
manipulated with ifup/ifdown. Also `/etc/init.d/network reload` didn't
modify the batadv meshif interface configuration correctly.

The "batadv" is now renamed to "batadv_hardif" and a new "batadv" proto is
used to configure the main (meshif) network interface with all its
configuration.

A simple network configuration with WiFi & ethernet interfaces and static
IP on top of bat0 would look like:

  # batadv meshif bat0
  config interface 'bat0'
  	option proto 'batadv'
  	option routing_algo 'BATMAN_IV'
  	option aggregated_ogms 1
  	option ap_isolation 0
  	option bonding 0
  	option fragmentation 1
  	#option gw_bandwidth '10000/2000'
  	option gw_mode 'off'
  	#option gw_sel_class 20
  	option log_level 0
  	option orig_interval 1000
  	option bridge_loop_avoidance 1
  	option distributed_arp_table 1
  	option multicast_mode 1
  	option network_coding 0
  	option hop_penalty 30
  	option isolation_mark '0x00000000/0x00000000'

  # add *single* wifi-iface with network bat0_hardif_wlan as hardif to bat0
  config interface 'bat0_hardif_wlan'
  	option mtu '1536'
  	option proto 'batadv_hardif'
  	option master 'bat0'
  	# option ifname is filled out by the wifi-iface

  # add eth0 as hardif to bat0
  config interface 'bat0_hardif_eth0'
  	option proto 'batadv_hardif'
  	option master 'bat0'
  	option ifname 'eth0'
  	option mtu '1536'

  # configure IP on bat0
  config interface 'bat0_lan'
  	option ifname 'bat0'
  	option proto 'static'
  	option ipaddr '192.168.1.1'
  	option netmask '255.255.255.0'
  	option ip6assign '60'

Signed-off-by: Sven Eckelmann <sven@narfation.org>