busybox/examples/udhcp/simple.script
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   1#!/bin/sh
   2# udhcpc script edited by Tim Riker <Tim@Rikers.org>
   3
   4RESOLV_CONF="/etc/resolv.conf"
   5
   6[ -n "$1" ] || { echo "Error: should be called from udhcpc"; exit 1; }
   7
   8NETMASK=""
   9if command -v ip >/dev/null; then
  10        [ -n "$subnet" ] && NETMASK="/$subnet"
  11else
  12        [ -n "$subnet" ] && NETMASK="netmask $subnet"
  13fi
  14BROADCAST="broadcast +"
  15[ -n "$broadcast" ] && BROADCAST="broadcast $broadcast"
  16
  17case "$1" in
  18        deconfig)
  19                echo "Setting IP address 0.0.0.0 on $interface"
  20                if command -v ip >/dev/null; then
  21                        ip addr flush dev $interface
  22                else
  23                        ifconfig $interface 0.0.0.0
  24                fi
  25                ;;
  26
  27        renew|bound)
  28                echo "Setting IP address $ip on $interface"
  29                if command -v ip >/dev/null; then
  30                        ip addr add $ip$NETMASK $BROADCAST dev $interface
  31                else
  32                        ifconfig $interface $ip $NETMASK $BROADCAST
  33                fi
  34
  35                if [ -n "$router" ] ; then
  36                        echo "Deleting routers"
  37                        while route del default gw 0.0.0.0 dev $interface ; do
  38                                :
  39                        done
  40
  41                        metric=0
  42                        for i in $router ; do
  43                                echo "Adding router $i"
  44                                if [ "$subnet" = "255.255.255.255" ]; then
  45        # special case for /32 subnets:
  46        # /32 instructs kernel to always use routing for all outgoing packets
  47        # (they can never be sent to local subnet - there is no local subnet for /32).
  48        # Used in datacenters, avoids the need for private ip-addresses between two hops.
  49                                        ip route add $i dev $interface
  50                                fi
  51                                route add default gw $i dev $interface metric $((metric++))
  52                        done
  53                fi
  54
  55                echo "Recreating $RESOLV_CONF"
  56                # If the file is a symlink somewhere (like /etc/resolv.conf
  57                # pointing to /run/resolv.conf), make sure things work.
  58                if test -L "$RESOLV_CONF"; then
  59                        # If it's a dangling symlink, try to create the target.
  60                        test -e "$RESOLV_CONF" || touch "$RESOLV_CONF"
  61                fi
  62                realconf=$(readlink -f "$RESOLV_CONF" 2>/dev/null || echo "$RESOLV_CONF")
  63                tmpfile="$realconf-$$"
  64                > "$tmpfile"
  65                [ -n "$domain" ] && echo "search $domain" >> "$tmpfile"
  66                for i in $dns ; do
  67                        echo " Adding DNS server $i"
  68                        echo "nameserver $i" >> "$tmpfile"
  69                done
  70                mv "$tmpfile" "$realconf"
  71                ;;
  72esac
  73
  74exit 0
  75