7.8. Configuring the network Script

Which interfaces are brought up and down by the network utilities depends on the files and directories in the /etc/network directory. The interfaces file should contain a description of the interfaces, as done by Debian, and each of the directories contain scripts for actions to perform on each type of network event.

The following command creates the required directories and the interfaces file, assuming DHCP will be used for eth0:

mkdir -pv ${CLFS}/targetfs/etc/network/if-{post-{up,down},pre-{up,down},up,down}.d
mkdir -pv ${CLFS}/targetfs/usr/share/udhcpc

cat > ${CLFS}/targetfs/etc/network/interfaces << "EOF"
auto eth0
iface eth0 inet dhcp
EOF

For DHCP to work properly with udhcpc, the BusyBox dhcp client, a configuration script is needed. Create a simple script to assign the provided DHCP address and update /etc/resolv.conf:

cat > ${CLFS}/targetfs/usr/share/udhcpc/default.script << "EOF"
#!/bin/sh
# udhcpc Interface Configuration
# Based on http://lists.debian.org/debian-boot/2002/11/msg00500.html
# udhcpc script edited by Tim Riker <Tim@Rikers.org>

[ -z "$1" ] && echo "Error: should be called from udhcpc" && exit 1

RESOLV_CONF="/etc/resolv.conf"
[ -n "$broadcast" ] && BROADCAST="broadcast $broadcast"
[ -n "$subnet" ] && NETMASK="netmask $subnet"

case "$1" in
        deconfig)
                /sbin/ifconfig $interface 0.0.0.0
                ;;

        renew|bound)
                /sbin/ifconfig $interface $ip $BROADCAST $NETMASK

                if [ -n "$router" ] ; then
                        while route del default gw 0.0.0.0 dev $interface ; do
                                true
                        done

                        for i in $router ; do
                                route add default gw $i dev $interface
                        done
                fi

                echo -n > $RESOLV_CONF
                [ -n "$domain" ] && echo search $domain >> $RESOLV_CONF
                for i in $dns ; do
                        echo nameserver $i >> $RESOLV_CONF
                done
                ;;
esac

exit 0
EOF

chmod +x ${CLFS}/targetfs/usr/share/udhcpc/default.script