[Buildroot] [PATCH] Allow a single DHCP configuration via the system configuration submenu

[Jeremy Rosen <jeremy.rosen@openwide.fr>]

Hey Samuel


----- Mail original -----
> Hi Jeremy,
> 
> On Wed, Dec 17, 2014 at 5:15 PM, J?r?my Rosen
> <jeremy.rosen@openwide.fr> wrote:
> > This patch allows the setup of simple a single interface to be
> > automatically brought up and configured via DHCP on system startup.
> >
> > The interface name can be set via a configuration option. This
> > patch
> > does not support systemd-networkd, any complex network
> > configuration should
> > be done via overlay of /etc/network/interfaces or the relevant
> > networkd
> > configuration file
> >
> > Signed-off-by: J?r?my Rosen <jeremy.rosen@openwide.fr>
> > ---
> >  support/scripts/generate-network-config.sh | 24
> >  ++++++++++++++++++++++++
> >  system/Config.in                           | 18 ++++++++++++++++++
> >  system/skeleton/etc/network/interfaces     |  4 ----
> >  system/system.mk                           |  5 +++++
> >  4 files changed, 47 insertions(+), 4 deletions(-)
> >  create mode 100755 support/scripts/generate-network-config.sh
> >  delete mode 100644 system/skeleton/etc/network/interfaces
> >
> > diff --git a/support/scripts/generate-network-config.sh
> > b/support/scripts/generate-network-config.sh
> > new file mode 100755
> > index 0000000..92f8d16
> > --- /dev/null
> > +++ b/support/scripts/generate-network-config.sh
> > @@ -0,0 +1,24 @@
> > +#!/bin/sh
> > +
> > +export BR2_SIMPLE_DHCP=$(sed -r -e "/^BR2_SIMPLE_DHCP=(.*)$/!d;"
> > -e 's//\1/;' $BR2_CONFIG)
> > +
> > +export BR2_SIMPLE_DHCP_INTERFACE="$(sed -r -e
> > "/^BR2_SIMPLE_DHCP_INTERFACE=\"(.*)\"$/!d;" -e 's//\1/;'
> > $BR2_CONFIG)"
> > +
> > +do_generate_interfaces ()
> > +{
> > +       echo "# interface file auto-generated by buildroot"
> > +       echo
> > +       echo "auto lo"
> > +       echo "iface lo inet loopback"
> > +       echo
> > +
> > +       if [ -z "$BR2_SIMPLE_DHCP" ] ; then
> > +               return
> > +        fi
> > +
> > +       echo "auto $BR2_SIMPLE_DHCP_INTERFACE"
> > +       echo "iface $BR2_SIMPLE_DHCP_INTERFACE inet dhcp"
> > +}
> > +
> > +mkdir -p $TARGET_DIR/etc/network/
> > +do_generate_interfaces > $TARGET_DIR/etc/network/interfaces
> > diff --git a/system/Config.in b/system/Config.in
> > index a3b7aff..10a81e9 100644
> > --- a/system/Config.in
> > +++ b/system/Config.in
> > @@ -324,6 +324,24 @@ config BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW
> >
> >  endif # BR2_ROOTFS_SKELETON_DEFAULT
> >
> > +config BR2_SIMPLE_DHCP
> > +       bool "automatic network configuration via DHCP"
> > +       default n
> > +       depends on !BR2_PACKAGE_SYSTEMD_NETWORKD
> > +       help
> > +         Automatically do a DHCP request on startup on selected
> > interface at
> > +         startup. For more complicated setups use an overlay.
> > +
> > +comment "automatic network configuration via DHCP is not
> > compatible with networkd"
> > +       depends on BR2_PACKAGE_SYSTEMD_NETWORKD
> 
> IIRC, comment does not support help message, but it could be
> worthwhile to document somewhere how to do this in the systemd case,
> without needing reading the git log ;-)
> 

well, the answer is "the usual way, use overlays" and "read the man
page for networkd".

systemd in general has pretty good set of docs, and we don't document
most of the ways to customize your image. BR users are supposed to
know system configuration (we don't document /etc/network/interfaces)

so I personally think it's not really needed, but if you think it's
really necessary and you tell me where to add a note, I can write
something... I have a good understanding of networkd with my previous
attempt at network configuration


> > +
> > +config BR2_SIMPLE_DHCP_INTERFACE
> > +       string "name of the physical network interface to run DHCP
> > on"
> > +       depends on BR2_SIMPLE_DHCP
> > +       default eth0
> > +       help
> > +         The name of the network interface to configure
> > automatically
> > +
> >  config BR2_TARGET_TZ_INFO
> >         bool "Install timezone info"
> >         # No timezone for musl; only for uClibc or (e)glibc.
> > diff --git a/system/skeleton/etc/network/interfaces
> > b/system/skeleton/etc/network/interfaces
> > deleted file mode 100644
> > index 218b82c..0000000
> > --- a/system/skeleton/etc/network/interfaces
> > +++ /dev/null
> > @@ -1,4 +0,0 @@
> > -# Configure Loopback
> > -auto lo
> > -iface lo inet loopback
> > -
> > diff --git a/system/system.mk b/system/system.mk
> > index e4a3160..bb933f6 100644
> > --- a/system/system.mk
> > +++ b/system/system.mk
> > @@ -38,6 +38,11 @@ ifneq ($(TARGET_GENERIC_ROOT_PASSWD),)
> >  TARGETS += host-mkpasswd
> >  endif
> >
> > +define SIMPLE_NETWORK
> > +       $(TOPDIR)/support/scripts/generate-network-config.sh
> > $(TARGET_DIR)
> > +endef
> > +TARGET_FINALIZE_HOOKS += SIMPLE_NETWORK
> > +
> >  ifeq ($(BR2_ROOTFS_SKELETON_DEFAULT),y)
> >
> >  define SYSTEM_ROOT_PASSWD
> > --
> > 2.1.3
> >
> > _______________________________________________
> > buildroot mailing list
> > buildroot at busybox.net
> > http://lists.busybox.net/mailman/listinfo/buildroot
> 
> Regards,
> 
> --
> Samuel
>