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doc:techref:netifd [2013/07/14 10:50]
lorema
doc:techref:netifd [2015/05/31 14:10] (current)
jow old revision restored (2015/05/30 20:56)
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 +====== netifd (Network Interface Daemon) – Technical Reference ======
 +
 +  * [[http://​git.openwrt.org/?​p=project/​netifd.git;​a=summary|Project'​s git]]
 +  * netifd is available in OpenWrt since [[https://​dev.openwrt.org/​changeset/​28499|R28499 (trunk)]] and published under the GPLv2.
 +  * [[https://​dev.openwrt.org/​search?​changeset=on&​milestone=on&​wiki=on&​q=netifd&​page=1&​noquickjump=1|commits to OpenWrt trunk regarding netifd]]
 +  * [[http://​git.openwrt.org/?​p=project/​netifd.git;​a=blob;​f=DESIGN|Design of netifd]]
 +
 +==== What is netifd? ====
 +''​netifd''​ is an [[wp>​Remote procedure call|RPC]]-capable [[wp>​Daemon (computing)|daemon]] written in [[wp>C (programming language)|C]] for better access to kernel APIs with the ability to listen on [[wp>​Netlink|netlink events]]. ''​Netifd''​ has replaced the old //​OpenWrt-network configuration scripts//, the actual scripts that configured the network, e.g.
 +  * ''/​lib/​network/​*.sh'',​
 +  * ''/​sbin/​ifup''​
 +  * some scripts in ''/​etc/​hotplug.d''​.)
 +
 +''​netifd''​ is intended to stay compatible with the existing format of ''​[[doc:​uci:​network|/​etc/​config/​network]]'',​ the only exceptions being rare special cases like 
 +aliases or the overlay variables in ''/​var/​state''​ (though even most of those can be easily emulated).
 +
 +==== Help with the development of netifd ====
 +  - test what has been ported
 +  - review of the code
 +  - help porting more of our protocol handler scripts (so far, static, ppp, pppoe, pppoa and dhcp are supported)
 +
 +==== Why do we want netifd? ====
 +One thing that ''​netifd''​ does much better then old //​OpenWrt-network configuration scripts// is handling configuration changes. With ''​netfid'',​ when the file ''​[[doc:​uci:​network|/​etc/​config/​network]]''​ changes, you no longer have to restart all interfaces. Simply run **''/​etc/​init.d/​network reload''​**. This will issue an ''​ubus''​-call to ''​netifd'',​ telling it to figure out the difference between runtime state and the new config and apply only that. This works on a per-interface level, even with protocol handlers written as shell scripts.
 +
 +It boils down to the fact that the current network and interface setup mechanisms (via network configuration scripts) are rather constrained and inflexible:
 +  * lack of statefulness
 +  * tendency for raceconditions
 +  * inability to properly nest protocols
 +  * limited featureset of the ash shell which will not allow for complex interface operations like e.g. calculating [[wp>​Unique local address|ULAs]]
 +  * you name it
 +
 +''​Netifd''​ will be able to manage even complex interface configurations with a mix of bonding, vlans, bridges, etc. and handle the dependencies ​
 +between interfaces properly - and of course all that without adding unnecessary bloat. AFAIK there are no alternatives to netifd, e.g. [[https://​connman.net/​|connman]] seems to be centered around one specifific use case only: having a mobile device access the internet through multiple connections.
 +
 +===== OpenWrt – operating system architecture =====
 +{{page>​doc:​techref:​architecture&​noheader&​nofooter}}
 +