[B.A.T.M.A.N.] [PATCHv2] alfred: optionally bundle a lua script for generating a bat-hosts

Gui Iribarren
2013-11-12T19:28:46Z

Provide a lua script that uses alfred to propagate and collect all
interface mac + names, then generate a /tmp/bat-hosts file.
If there's already a (probably hand-made) /etc/bat-hosts it won't overwrite it,
but if there's none, it will symlink /etc/bat-hosts -> /tmp/bat-hosts

Signed-off-by: Gui Iribarren <gui@altermundi.net>
Thanks-to: Joshua Head <joshua.head@outlook.com>
---

ChangeLog v2: make the script selectable through menuconfig, disabled by default

alfred/Config.in | 9 ++++
alfred/Makefile | 3 ++
alfred/files/bat-hosts.lua | 107 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 119 insertions(+)
create mode 100644 alfred/files/bat-hosts.lua

diff --git a/alfred/Config.in b/alfred/Config.in
index 1791949..97f9ea2 100644
--- a/alfred/Config.in
+++ b/alfred/Config.in
@@ -1,3 +1,6 @@
+config ALFRED_NEEDS_lua
+ bool
+
config ALFRED_NEEDS_libgps
bool

@@ -6,6 +9,12 @@ config PACKAGE_ALFRED_VIS
depends on PACKAGE_alfred
default y

+config PACKAGE_ALFRED_BATHOSTS
+ bool "enable autogeneration of /etc/bat-hosts"
+ depends on PACKAGE_alfred
+ select ALFRED_NEEDS_lua
+ default n
+
config PACKAGE_ALFRED_GPSD
bool "enable gpsd service for alfred"
depends on PACKAGE_alfred
diff --git a/alfred/Makefile b/alfred/Makefile
index 67be82f..b6d8255 100644
--- a/alfred/Makefile
+++ b/alfred/Makefile
@@ -28,6 +28,7 @@ define Package/alfred
CATEGORY:=Network
TITLE:=A.L.F.R.E.D. - Almighty Lightweight Fact Remote Exchange Daemon
DEPENDS:= +libc +IPV6:kmod-ipv6 +librt \
+ +ALFRED_NEEDS_lua:lua \
+ALFRED_NEEDS_libgps:libgps
endef

@@ -77,6 +78,8 @@ define Package/alfred/install
$(INSTALL_BIN) ./files/alfred.init $(1)/etc/init.d/alfred
$(INSTALL_DIR) $(1)/etc/config
$(INSTALL_DATA) ./files/alfred.config $(1)/etc/config/alfred
+ $(INSTALL_DIR) $(1)/etc/alfred
+ [ "x$(CONFIG_PACKAGE_ALFRED_BATHOSTS)" == "xy" ] && $(INSTALL_BIN) ./files/bat-hosts.lua $(1)/etc/alfred/bat-hosts.lua ; true
endef

$(eval $(call BuildPackage,alfred))
diff --git a/alfred/files/bat-hosts.lua b/alfred/files/bat-hosts.lua
new file mode 100644
index 0000000..8648caf
--- /dev/null
+++ b/alfred/files/bat-hosts.lua
@@ -0,0 +1,107 @@
+#!/usr/bin/lua
+
+local type_id = 64 -- bat-hosts
+
+function get_hostname()
+ local hostfile = io.open("/proc/sys/kernel/hostname", "r")
+ local ret_string = hostfile:read()
+ hostfile:close()
+ return ret_string
+end
+
+function get_interfaces_names()
+ local ret = {}
+
+ for name in io.popen("ls -1 /sys/class/net/"):lines() do
+ table.insert(ret, name)
+ end
+
+ return ret
+end
+
+function get_interface_address(name)
+ local addressfile = io.open("/sys/class/net/"..name.."/address", "r")
+ local ret_string = addressfile:read()
+ addressfile:close()
+ return ret_string
+end
+
+
+local function generate_bat_hosts()
+-- get hostname and interface macs/names
+-- then return a table containing valid bat-hosts lines
+ local n, i
+ local ifaces, ret = {}, {}
+
+ local hostname = get_hostname()
+
+ for n, i in ipairs(get_interfaces_names()) do
+ local address = get_interface_address(i)
+ if not ifaces[address] then ifaces[address] = i end
+ end
+
+ for mac, iname in pairs(ifaces) do
+ if mac:match("^%x%x:%x%x:%x%x:%x%x:%x%x:%x%x$") and not mac:match("00:00:00:00:00:00") then
+ table.insert(ret, mac.." "..hostname.."_"..iname.."\n")
+ end
+ end
+
+ return ret
+end
+
+local function publish_bat_hosts()
+-- pass a raw chunk of data to alfred
+ local fd = io.popen("alfred -s " .. type_id, "w")
+ if fd then
+ local ret = generate_bat_hosts()
+ if ret then
+ fd:write(table.concat(ret))
+ end
+ fd:close()
+ end
+end
+
+local function write_bat_hosts(rows)
+ local content = { "### /tmp/bat-hosts generated by alfred-bat-hosts\n",
+ "### /!\\ This file is overwritten every 5 minutes /!\\\n",
+ "### (To keep manual changes, replace /etc/bat-hosts symlink with a static file)\n" }
+
+ -- merge the chunks from all nodes, de-escaping newlines
+ for _, row in ipairs(rows) do
+ local node, value = unpack(row)
+ table.insert(content, "# Node ".. node .. "\n")
+ table.insert(content, value:gsub("\x0a", "\n") .. "\n")
+ end
+
+ -- write parsed content down to disk
+ local fd = io.open("/tmp/bat-hosts", "w")
+ if fd then
+ fd:write(table.concat(content))
+ fd:close()
+ end
+
+ -- try to make a symlink in /etc pointing to /tmp,
+ -- if it exists, ln will do nothing.
+ os.execute("ln -ns /tmp/bat-hosts /etc/bat-hosts 2>/dev/null")
+end
+
+local function receive_bat_hosts()
+-- read raw chunks from alfred, convert them to a nested table and call write_bat_hosts
+ local fd = io.popen("alfred -r " .. type_id)
+ --[[ this command returns something like
+ { "54:e6:fc:b9:cb:37", "00:11:22:33:44:55 ham_wlan0\x0a00:22:33:22:33:22 ham_eth0\x0a" },
+ { "90:f6:52:bb:ec:57", "00:22:33:22:33:23 spam\x0a" },
+ ]]--
+
+ if fd then
+ local output = fd:read("*a")
+ if output then
+ assert(loadstring("rows = {" .. output .. "}"))()
+ write_bat_hosts(rows)
+ end
+ fd:close()
+ end
+end
+
+publish_bat_hosts()
+receive_bat_hosts()
--
1.7.10.4