README - platform/external/dhcpcd-6.8.2 - Git at Google

 dhcpcd - DHCP client daemon
 Copyright (c) 2006-2015 Roy Marples <roy@marples.name>


 Installation
 ------------
 ./configure; make; make install
 man dhcpcd for command line options
 man dhcpcd.conf for configuration options
 man dhcpcd-run-hooks to learn how to hook scripts into dhcpcd events


 Notes
 -----
 If you're cross compiling you may need set the platform if OS is different
 from the host.
 --target=sparc-sun-netbsd5.0

 If you're building for an MMU-less system where fork() does not work, you
 should ./configure --disable-fork.
 This also puts the --no-background flag on and stops the --background flag
 from working.

 You can change the default dirs with these knobs.
 For example, to satisfy FHS compliance you would do this:-
 ./configure --libexecdir=/lib/dhcpcd dbdir=/var/lib/dhcpcd

 We now default to using -std=c99. For 64-bit linux, this always works, but
 for 32-bit linux it requires either gnu99 or a patch to asm/types.h.
 Most distros patch linux headers so this should work fine.
 linux-2.6.24 finally ships with a working 32-bit header.
 If your linux headers are older, or your distro hasn't patched them you can
 set CSTD=gnu99 to work around this.

 Some BSD systems do not allow the manipulation of automatically added subnet
 routes. You can find discussion here:
     http://mail-index.netbsd.org/tech-net/2008/12/03/msg000896.html
 BSD systems where this has been fixed or is known to work are:
     NetBSD-5.0
     FreeBSD-10.0

 Some BSD systems protect against IPv6 NS/NA messages by ensuring that the
 source address matches a prefix on the recieved by a RA message.
 This is an error as the correct check is for on-link prefixes as the
 kernel may not be handling RA itself.
 BSD systems where this has been fixed or is known to work are:
     NetBSD-7.0
     OpenBSD-5.0
     patch submitted against FreeBSD-10.0

 Some BSD systems do not announce IPv6 address flag changes, such as
 IN6_IFF_TENTATIVE, IN6_IFF_DUPLICATED, etc. On these systems,
 dhcpcd will poll a freshly added address until either IN6_IFF_TENTATIVE is
 cleared or IN6_IFF_DUPLICATED is set and take action accordingly.
 BSD systems where this has been fixed or is known to work are:
     NetBSD-7.0

 Some BSD systems do not announce cached neighbour route changes based
 on reachability to userland. For such systems, IPv6 routers will always
 be assumed to be reachable until they either stop being a router or expire.
 BSD systems where this has been fixed or is known to work are:
     NetBSD-7.99.3

 Linux prior to 3.17 won't allow userland to manage IPv6 temporary addresses.
 Either upgrade or don't allow dhcpcd to manage the RA,
 so don't set either "ipv6ra_own" or "slaac private" in dhcpcd.conf if you
 want to have working IPv6 temporary addresses.
 SLAAC private addresses are just as private, just stable.

 ArchLinux presently sanitises all kernel headers to the latest version
 regardless of the version for your CPU. As such, Arch presently ships a
 3.12 kernel with 3.17 headers which claim that it suppors temporary address
 management and no automatic prefix route generation, both of which are
 obviously false. You will have to patch support either in the kernel or
 out of the headers (or dhcpcd itself) to have correct operation.

 We try and detect how dhcpcd should interact with system services at runtime.
 If we cannot auto-detect how do to this, or it is wrong then
 you can change this by passing shell commands to --serviceexists,
 --servicecmd and optionally --servicestatus to ./configure or overriding
 the service variables in a hook.

 Some systems have /dev management systems and some of these like to rename
 interfaces. As this system would listen in the same way as dhcpcd to new
 interface arrivals, dhcpcd needs to listen to the /dev management sytem
 instead of the kernel. However, if the /dev management system breaks, stops
 working, or changes to a new one, dhcpcd should still try and continue to work.
 To facilitate this, dhcpcd allows a plugin to load to instruct dhcpcd when it
 can use an interface. As of the time of writing only udev support is included.
 You can disable this with --without-dev, or without-udev

 To shrink dhcpcd you can disable IPv4 or IPv6:
 	--disable-inet
 	--disable-inet6

 You can also move the embedded extended configuration from the dhcpcd binary
 to an external file (LIBEXECDIR/dhcpcd-definitions.conf)
 	--disable-embedded
 If dhcpcd cannot load this file at runtime, dhcpcd will work but will not be
 able to decode any DHCP/DHCPv6 options that are not defined by the user
 in /etc/dhcpcd.conf.

 To prepare dhcpcd for import into a platform source tree (like NetBSD)
 you can use the make import target to create /tmp/dhcpcd-$version and
 populate it with all the source files and hooks needed.
 In this instance, you may wish to disable some configured tests when
 the binary has to run on older versions which lack support, such as getline.
 ./configure --without-getline

 Building for distribution (ie making a dhcpcd source tarball) now requires
 gmake-4 or any BSD make.


 Hooks
 -----
 Not all the hooks in dhcpcd-hooks are installed by default.
 By default we install 01-test, 02-dump, 10-mtu, 10-wpa_supplicant,
 15-timezone, 20-resolv.conf, 29-lookup-hostname and 30-hostname.
 The default dhcpcd.conf disables the lookup-hostname hook by default.
 The configure program attempts to find hooks for systems you have installed.
 To add more simply
 ./configure -with-hook=ntp.conf

 Some system services expose the name of the service we are in,
 by default dhcpcd will pick RC_SVCNAME from the environment.
 You can override this in CPPFLAGS+= -DRC_SVCNAME="YOUR_SVCNAME".
 This is important because dhcpcd will scrub the environment aside from $PATH
 before running hooks.
 This variable could be used to facilitate service re-entry so this chain could
 happen in a custom OS hook:
   dhcpcd service marked inactive && dhcpcd service starts
   dependant services are not started because dhcpcd is inactive (not stopped)
   dhcpcd hook tests $if_oneup && $if_ipwaited
   if true, mark the dhcpcd service as started and then start dependencies
   if false and the dhcpcd service was previously started, mark as inactive and
      stop any dependant services.


 Compatibility
 -------------
 dhcpcd-5.0 is only fully command line compatible with dhcpcd-4.0
 For compatibility with older versions, use dhcpcd-4.0


 ChangeLog
 ---------
 We no longer supply a ChangeLog.
 However, you're more than welcome to read the commit log at
 http://roy.marples.name/projects/dhcpcd/timeline/
	dhcpcd - DHCP client daemon
	Copyright (c) 2006-2015 Roy Marples <roy@marples.name>


	Installation
	------------
	./configure; make; make install
	man dhcpcd for command line options
	man dhcpcd.conf for configuration options
	man dhcpcd-run-hooks to learn how to hook scripts into dhcpcd events


	Notes
	-----
	If you're cross compiling you may need set the platform if OS is different
	from the host.
	--target=sparc-sun-netbsd5.0

	If you're building for an MMU-less system where fork() does not work, you
	should ./configure --disable-fork.
	This also puts the --no-background flag on and stops the --background flag
	from working.

	You can change the default dirs with these knobs.
	For example, to satisfy FHS compliance you would do this:-
	./configure --libexecdir=/lib/dhcpcd dbdir=/var/lib/dhcpcd

	We now default to using -std=c99. For 64-bit linux, this always works, but
	for 32-bit linux it requires either gnu99 or a patch to asm/types.h.
	Most distros patch linux headers so this should work fine.
	linux-2.6.24 finally ships with a working 32-bit header.
	If your linux headers are older, or your distro hasn't patched them you can
	set CSTD=gnu99 to work around this.

	Some BSD systems do not allow the manipulation of automatically added subnet
	routes. You can find discussion here:
	http://mail-index.netbsd.org/tech-net/2008/12/03/msg000896.html
	BSD systems where this has been fixed or is known to work are:
	NetBSD-5.0
	FreeBSD-10.0

	Some BSD systems protect against IPv6 NS/NA messages by ensuring that the
	source address matches a prefix on the recieved by a RA message.
	This is an error as the correct check is for on-link prefixes as the
	kernel may not be handling RA itself.
	BSD systems where this has been fixed or is known to work are:
	NetBSD-7.0
	OpenBSD-5.0
	patch submitted against FreeBSD-10.0

	Some BSD systems do not announce IPv6 address flag changes, such as
	IN6_IFF_TENTATIVE, IN6_IFF_DUPLICATED, etc. On these systems,
	dhcpcd will poll a freshly added address until either IN6_IFF_TENTATIVE is
	cleared or IN6_IFF_DUPLICATED is set and take action accordingly.
	BSD systems where this has been fixed or is known to work are:
	NetBSD-7.0

	Some BSD systems do not announce cached neighbour route changes based
	on reachability to userland. For such systems, IPv6 routers will always
	be assumed to be reachable until they either stop being a router or expire.
	BSD systems where this has been fixed or is known to work are:
	NetBSD-7.99.3

	Linux prior to 3.17 won't allow userland to manage IPv6 temporary addresses.
	Either upgrade or don't allow dhcpcd to manage the RA,
	so don't set either "ipv6ra_own" or "slaac private" in dhcpcd.conf if you
	want to have working IPv6 temporary addresses.
	SLAAC private addresses are just as private, just stable.

	ArchLinux presently sanitises all kernel headers to the latest version
	regardless of the version for your CPU. As such, Arch presently ships a
	3.12 kernel with 3.17 headers which claim that it suppors temporary address
	management and no automatic prefix route generation, both of which are
	obviously false. You will have to patch support either in the kernel or
	out of the headers (or dhcpcd itself) to have correct operation.

	We try and detect how dhcpcd should interact with system services at runtime.
	If we cannot auto-detect how do to this, or it is wrong then
	you can change this by passing shell commands to --serviceexists,
	--servicecmd and optionally --servicestatus to ./configure or overriding
	the service variables in a hook.

	Some systems have /dev management systems and some of these like to rename
	interfaces. As this system would listen in the same way as dhcpcd to new
	interface arrivals, dhcpcd needs to listen to the /dev management sytem
	instead of the kernel. However, if the /dev management system breaks, stops
	working, or changes to a new one, dhcpcd should still try and continue to work.
	To facilitate this, dhcpcd allows a plugin to load to instruct dhcpcd when it
	can use an interface. As of the time of writing only udev support is included.
	You can disable this with --without-dev, or without-udev

	To shrink dhcpcd you can disable IPv4 or IPv6:
	--disable-inet
	--disable-inet6

	You can also move the embedded extended configuration from the dhcpcd binary
	to an external file (LIBEXECDIR/dhcpcd-definitions.conf)
	--disable-embedded
	If dhcpcd cannot load this file at runtime, dhcpcd will work but will not be
	able to decode any DHCP/DHCPv6 options that are not defined by the user
	in /etc/dhcpcd.conf.

	To prepare dhcpcd for import into a platform source tree (like NetBSD)
	you can use the make import target to create /tmp/dhcpcd-$version and
	populate it with all the source files and hooks needed.
	In this instance, you may wish to disable some configured tests when
	the binary has to run on older versions which lack support, such as getline.
	./configure --without-getline

	Building for distribution (ie making a dhcpcd source tarball) now requires
	gmake-4 or any BSD make.


	Hooks
	-----
	Not all the hooks in dhcpcd-hooks are installed by default.
	By default we install 01-test, 02-dump, 10-mtu, 10-wpa_supplicant,
	15-timezone, 20-resolv.conf, 29-lookup-hostname and 30-hostname.
	The default dhcpcd.conf disables the lookup-hostname hook by default.
	The configure program attempts to find hooks for systems you have installed.
	To add more simply
	./configure -with-hook=ntp.conf

	Some system services expose the name of the service we are in,
	by default dhcpcd will pick RC_SVCNAME from the environment.
	You can override this in CPPFLAGS+= -DRC_SVCNAME="YOUR_SVCNAME".
	This is important because dhcpcd will scrub the environment aside from $PATH
	before running hooks.
	This variable could be used to facilitate service re-entry so this chain could
	happen in a custom OS hook:
	dhcpcd service marked inactive && dhcpcd service starts
	dependant services are not started because dhcpcd is inactive (not stopped)
	dhcpcd hook tests $if_oneup && $if_ipwaited
	if true, mark the dhcpcd service as started and then start dependencies
	if false and the dhcpcd service was previously started, mark as inactive and
	stop any dependant services.


	Compatibility
	-------------
	dhcpcd-5.0 is only fully command line compatible with dhcpcd-4.0
	For compatibility with older versions, use dhcpcd-4.0


	ChangeLog
	---------
	We no longer supply a ChangeLog.
	However, you're more than welcome to read the commit log at
	http://roy.marples.name/projects/dhcpcd/timeline/