ip/ifcfg

   1 #! /bin/bash
   2
   3 CheckForwarding () {
   4   local sbase fwd
   5   sbase=/proc/sys/net/ipv4/conf
   6   fwd=0
   7   if [ -d $sbase ]; then
   8     for dir in $sbase/*/forwarding; do
   9       fwd=$[$fwd + `cat $dir`]
  10     done
  11   else
  12     fwd=2
  13   fi
  14   return $fwd
  15 }
  16
  17 RestartRDISC () {
  18   killall -HUP rdisc || rdisc -fs
  19 }
  20
  21 ABCMaskLen () {
  22   local class;
  23
  24   class=${1%%.*}
  25   if [ "$1" = "" -o $class -eq 0 -o $class -ge 224 ]; then return 0
  26   elif [ $class -ge 224 ]; then return 0
  27   elif [ $class -ge 192 ]; then return 24
  28   elif [ $class -ge 128 ]; then return 16
  29   else return 8; fi
  30 }
  31
  32 label="label $1"
  33 ldev="$1"
  34 dev=${1%:*}
  35 if [ "$dev" = "" -o "$1" = "help" ]; then
  36   echo "Usage: ifcfg DEV [[add|del [ADDR[/LEN]] [PEER] | stop]" 1>&2
  37   echo "       add - add new address" 1>&2
  38   echo "       del - delete address" 1>&2
  39   echo "       stop - completely disable IP" 1>&2
  40   exit 1
  41 fi
  42 shift
  43
  44 CheckForwarding
  45 fwd=$?
  46 if [ $fwd -ne 0 ]; then
  47   echo "Forwarding is ON or its state is unknown ($fwd). OK, No RDISC." 1>&2
  48 fi
  49
  50
  51 deleting=0
  52 case "$1" in
  53 add) shift ;;
  54 stop)
  55   if [ "$ldev" != "$dev" ]; then
  56     echo "Cannot stop alias $ldev" 1>&2
  57     exit 1;
  58   fi
  59   ip -4 addr flush dev $dev $label || exit 1
  60   if [ $fwd -eq 0 ]; then RestartRDISC; fi
  61   exit 0 ;;
  62 del*)
  63   deleting=1; shift ;;
  64 *)
  65 esac
  66
  67 ipaddr=
  68 pfxlen=
  69 if [ "$1" != "" ]; then
  70   ipaddr=${1%/*}
  71   if [ "$1" != "$ipaddr" ]; then
  72     pfxlen=${1#*/}
  73   fi
  74   if [ "$ipaddr" = "" ]; then
  75     echo "$1 is bad IP address." 1>&2
  76     exit 1
  77   fi
  78 fi
  79 shift
  80
  81 peer=$1
  82 if [ "$peer" != "" ]; then
  83   if [ "$pfxlen" != "" -a "$pfxlen" != "32" ]; then
  84     echo "Peer address with non-trivial netmask." 1>&2
  85     exit 1
  86   fi
  87   pfx="$ipaddr peer $peer"
  88 else
  89   if [ "$ipaddr" = "" ]; then
  90     echo "Missing IP address argument." 1>&2
  91     exit 1
  92   fi
  93   if [ "$pfxlen" = "" ]; then
  94     ABCMaskLen $ipaddr
  95     pfxlen=$?
  96   fi
  97   pfx="$ipaddr/$pfxlen"
  98 fi
  99
 100 if [ "$ldev" = "$dev" -a "$ipaddr" != "" ]; then
 101   label=
 102 fi
 103
 104 if [ $deleting -ne 0 ]; then
 105   ip addr del $pfx dev $dev $label || exit 1
 106   if [ $fwd -eq 0 ]; then RestartRDISC; fi
 107   exit 0
 108 fi
 109
 110
 111 if ! ip link set up dev $dev ; then
 112   echo "Error: cannot enable interface $dev." 1>&2
 113   exit 1
 114 fi
 115 if [ "$ipaddr" = "" ]; then exit 0; fi
 116
 117 if ! arping -q -c 2 -w 3 -D -I $dev $ipaddr ; then
 118   echo "Error: some host already uses address $ipaddr on $dev." 1>&2
 119   exit 1
 120 fi
 121
 122 if ! ip address add $pfx brd + dev $dev $label; then
 123   echo "Error: failed to add $pfx on $dev." 1>&2
 124   exit 1
 125 fi
 126
 127 arping -q -A -c 1 -I $dev $ipaddr
 128 noarp=$?
 129 ( sleep 2 ;
 130   arping -q -U -c 1 -I $dev $ipaddr ) >& /dev/null </dev/null &
 131
 132 ip route add unreachable 224.0.0.0/24 >& /dev/null
 133 ip route add unreachable 255.255.255.255 >& /dev/null
 134 if [ `ip link ls $dev | grep -c MULTICAST` -ge 1 ]; then
 135   ip route add 224.0.0.0/4 dev $dev scope global >& /dev/null
 136 fi
 137
 138 if [ $fwd -eq 0 ]; then
 139   if [ $noarp -eq 0 ]; then
 140     ip ro append default dev $dev metric 30000 scope global
 141   elif [ "$peer" != "" ]; then
 142     if ping -q -c 2 -w 4 $peer ; then
 143       ip ro append default via $peer dev $dev metric 30001
 144     fi
 145   fi
 146   RestartRDISC
 147 fi
 148
 149 exit 0