Change MAC schema generation (#715)

While ath9k/ath10k devices can supprt VIFs with any combination of MAC addresses, there are also adapters which have a hardware MAC filter which only allows a few bits to differ. This commit changes the addresses of all VIFs to ony differ in the last 3 bits, which is required to support many Ralink/Mediatek based WLAN adapters.

Technically, the new addresses are generated by calculating an MD5 hash of the primary MAC address and using a part of this hash as a prefix for the MAC addresses.

The addresses (BSSIDs) of the AP VIFs are also reused for the LAN and WAN interfaces in mesh-on-LAN/WAN mode to reduce the number of needed addresses, and thus reduce the chance of collisions. This is not a problem as the MAC addresses of the AP VIFs are never used except as BSSID, and thus not seen by routing protocols like batman-adv.

Fixes #648

[Matthias Schiffer: rewrote commit message]

package/gluon-client-bridge/files/lib/gluon/upgrade/320-gluon-client-bridge-wireless

@@ -21,14 +21,16 @@ local function configure_client(config, radio, index, suffix)
 
   uci:delete('wireless', name)
 
-  if config then
+  macaddr = util.generate_mac(3*index)
+
+  if config and macaddr then
     uci:section('wireless', 'wifi-iface', name,
       {
         device = radio,
         network = 'client',
         mode = 'ap',
         ssid = config.ssid,
-        macaddr = util.generate_mac(2, index),
+        macaddr = macaddr,
         ifname = suffix and 'client' .. suffix,
         disabled = disabled,
       }

package/gluon-core/Makefile

@@ -12,7 +12,7 @@ define Package/gluon-core
   SECTION:=gluon
   CATEGORY:=Gluon
   TITLE:=Base files of Gluon
-  DEPENDS:=+gluon-site +libgluonutil +lua-platform-info +luci-base +luci-lib-jsonc +odhcp6c +firewall
+  DEPENDS:=+gluon-site +libgluonutil +lua-platform-info +lua-hash +luci-base +luci-lib-jsonc +odhcp6c +firewall
 endef
 
 

package/gluon-core/files/usr/lib/lua/gluon/util.lua

@@ -30,6 +30,7 @@ local ipairs = ipairs
 local table = table
 
 local nixio = require 'nixio'
+local hash = require 'hash'
 local sysconfig = require 'gluon.sysconfig'
 local site = require 'gluon.site_config'
 local uci = require('luci.model.uci').cursor()
@@ -71,22 +72,37 @@ function node_id()
 end
 
 -- Generates a (hopefully) unique MAC address
--- The first parameter defines the function and the second
--- parameter an ID to add to the MAC address
--- Functions and IDs defined so far:
--- (1, 0): WAN (for mesh-on-WAN)
--- (1, 1): LAN (for mesh-on-LAN)
--- (2, n): client interface for the n'th radio
--- (3, n): adhoc interface for n'th radio
--- (4, 0): mesh VPN
--- (5, n): mesh interface for n'th radio (802.11s)
-function generate_mac(f, i)
-  local m1, m2, m3, m4, m5, m6 = string.match(sysconfig.primary_mac, '(%x%x):(%x%x):(%x%x):(%x%x):(%x%x):(%x%x)')
-  m1 = nixio.bit.bor(tonumber(m1, 16), 0x02)
-  m2 = (tonumber(m2, 16)+f) % 0x100
-  m3 = (tonumber(m3, 16)+i) % 0x100
+-- The parameter defines the ID to add to the mac addr
+--
+-- IDs defined so far:
+-- 0: client0; mesh-vpn
+-- 1: mesh0
+-- 2: ibss0
+-- 3: client1; mesh-on-wan
+-- 4: mesh1
+-- 5: ibss1
+-- 6: mesh-on-lan
+-- 7: unused
+function generate_mac(i)
+  if i > 7 or i < 0 then return nil end -- max allowed id (0b111)
 
-  return string.format('%02x:%02x:%02x:%s:%s:%s', m1, m2, m3, m4, m5, m6)
+  local hashed = string.sub(hash.md5(sysconfig.primary_mac), 0, 12)
+  local m1, m2, m3, m4, m5, m6 = string.match(hashed, '(%x%x)(%x%x)(%x%x)(%x%x)(%x%x)(%x%x)')
+
+  m1 = tonumber(m1, 16)
+  m6 = tonumber(m6, 16)
+
+  m1 = nixio.bit.bor(m1, 0x02)  -- set locally administered bit
+  m1 = nixio.bit.band(m1, 0xFE) -- unset the multicast bit
+
+  -- It's necessary that the first 45 bits of the mac do
+  -- not vary on a single hardware interface, since some chips are using
+  -- a hardware mac filter. (e.g 'ramips-rt305x')
+
+  m6 = nixio.bit.band(m6, 0xF8) -- zero the last three bits (space needed for counting)
+  m6 = m6 + i                   -- add virtual interface id
+
+  return string.format('%02x:%s:%s:%s:%s:%02x', m1, m2, m3, m4, m5, m6)
 end
 
 -- Iterate over all radios defined in UCI calling

package/gluon-mesh-batman-adv-core/files/lib/gluon/upgrade/300-gluon-mesh-batman-adv-core-wan

@@ -5,6 +5,6 @@ local uci = require('luci.model.uci').cursor()
 
 
 -- fix up duplicate mac addresses (for mesh-on-WAN)
-uci:set('network', 'wan', 'macaddr', util.generate_mac(1, 0))
+uci:set('network', 'wan', 'macaddr', util.generate_mac(3))
 uci:save('network')
 

package/gluon-mesh-batman-adv-core/files/lib/gluon/upgrade/320-gluon-mesh-batman-adv-core-wireless

@@ -29,7 +29,9 @@ local function configure_ibss(config, radio, index, suffix, disabled)
   uci:delete('network', name .. '_vlan')
   uci:delete('wireless', name)
 
-  if config then
+  macaddr = util.generate_mac(3*index+2)
+
+  if config and macaddr then
     if config.vlan then
       uci:section('network', 'interface', name,
         {
@@ -60,7 +62,7 @@ local function configure_ibss(config, radio, index, suffix, disabled)
         mode = 'adhoc',
         ssid = config.ssid,
         bssid = config.bssid,
-        macaddr = util.generate_mac(3, index),
+        macaddr = macaddr,
         mcast_rate = config.mcast_rate,
         ifname = suffix and 'ibss' .. suffix,
         disabled = disabled and 1 or 0,
@@ -77,7 +79,9 @@ local function configure_mesh(config, radio, index, suffix, disabled)
   uci:delete('network', name)
   uci:delete('wireless', name)
 
-  if config then
+  macaddr = util.generate_mac(3*index+1)
+
+  if config and macaddr then
     uci:section('network', 'interface', name,
       {
         proto = 'batadv',
@@ -92,7 +96,7 @@ local function configure_mesh(config, radio, index, suffix, disabled)
         mode = 'mesh',
         mesh_id = config.id,
         mesh_fwding = 0,
-        macaddr = util.generate_mac(5, index),
+        macaddr = macaddr,
         mcast_rate = config.mcast_rate,
         ifname = suffix and 'mesh' .. suffix,
         disabled = disabled and 1 or 0,

package/gluon-mesh-batman-adv-core/files/lib/gluon/upgrade/340-gluon-mesh-batman-adv-core-mesh-on-lan

@@ -28,7 +28,7 @@ if sysconfig.lan_ifname and not uci:get('network', 'mesh_lan') then
               , proto   = 'batadv'
               , mesh    = 'bat0'
               , mesh_no_rebroadcast = '1'
-              , macaddr = util.generate_mac(1, 1)
+              , macaddr = util.generate_mac(6)
               , auto    = enable and 1 or 0
   })
 

package/gluon-mesh-vpn-fastd/files/lib/gluon/upgrade/400-mesh-vpn-fastd

@@ -127,7 +127,7 @@ uci:section('network', 'interface', 'mesh_vpn',
 		  proto = 'batadv',
 		  mesh = 'bat0',
 		  mesh_no_rebroadcast = 1,
-		  macaddr = util.generate_mac(4, 0),
+		  macaddr = util.generate_mac(0),
 	  }
 )