LXR iproute2/ip/ifcfg

   1#! /bin/sh
   2# SPDX-License-Identifier: GPL-2.0
   3
   4CheckForwarding () {
   5  local sbase fwd
   6  sbase=/proc/sys/net/ipv4/conf
   7  fwd=0
   8  if [ -d $sbase ]; then
   9    for dir in $sbase/*/forwarding; do
  10      fwd=$(( fwd + $(cat "$dir") ))
  11    done
  12  else
  13    fwd=2
  14  fi
  15  return $fwd
  16}
  17
  18RestartRDISC () {
  19  killall -HUP rdisc || rdisc -fs
  20}
  21
  22ABCMaskLen () {
  23  local class;
  24
  25  class=${1%%.*}
  26  if [ "$1" = "" -o $class -eq 0 -o $class -ge 224 ]; then return 0
  27  elif [ $class -ge 224 ]; then return 0
  28  elif [ $class -ge 192 ]; then return 24
  29  elif [ $class -ge 128 ]; then return 16
  30  else return 8; fi
  31}
  32
  33label="label $1"
  34ldev="$1"
  35dev=${1%:*}
  36if [ "$dev" = "" -o "$1" = "help" ]; then
  37  echo "Usage: ifcfg DEV [[add|del [ADDR[/LEN]] [PEER] | stop]" 1>&2
  38  echo "       add - add new address" 1>&2
  39  echo "       del - delete address" 1>&2
  40  echo "       stop - completely disable IP" 1>&2
  41  exit 1
  42fi
  43shift
  44
  45CheckForwarding
  46fwd=$?
  47if [ $fwd -ne 0 ]; then
  48  echo "Forwarding is ON or its state is unknown ($fwd). OK, No RDISC." 1>&2
  49fi
  50
  51
  52deleting=0
  53case "$1" in
  54add) shift ;;
  55stop)
  56  if [ "$ldev" != "$dev" ]; then
  57    echo "Cannot stop alias $ldev" 1>&2
  58    exit 1;
  59  fi
  60  ip -4 addr flush dev $dev $label || exit 1
  61  if [ $fwd -eq 0 ]; then RestartRDISC; fi
  62  exit 0 ;;
  63del*)
  64  deleting=1; shift ;;
  65*)
  66esac
  67
  68ipaddr=
  69pfxlen=
  70if [ "$1" != "" ]; then
  71  ipaddr=${1%/*}
  72  if [ "$1" != "$ipaddr" ]; then
  73    pfxlen=${1#*/}
  74  fi
  75  if [ "$ipaddr" = "" ]; then
  76    echo "$1 is bad IP address." 1>&2
  77    exit 1
  78  fi
  79fi
  80shift
  81
  82peer=$1
  83if [ "$peer" != "" ]; then
  84  if [ "$pfxlen" != "" -a "$pfxlen" != "32" ]; then
  85    echo "Peer address with non-trivial netmask." 1>&2
  86    exit 1
  87  fi
  88  pfx="$ipaddr peer $peer"
  89else
  90  if [ "$ipaddr" = "" ]; then
  91    echo "Missing IP address argument." 1>&2
  92    exit 1
  93  fi
  94  if [ "$pfxlen" = "" ]; then
  95    ABCMaskLen $ipaddr
  96    pfxlen=$?
  97  fi
  98  pfx="$ipaddr/$pfxlen"
  99fi
 100
 101if [ "$ldev" = "$dev" -a "$ipaddr" != "" ]; then
 102  label=
 103fi
 104
 105if [ $deleting -ne 0 ]; then
 106  ip addr del $pfx dev $dev $label || exit 1
 107  if [ $fwd -eq 0 ]; then RestartRDISC; fi
 108  exit 0
 109fi
 110
 111
 112if ! ip link set up dev $dev ; then
 113  echo "Error: cannot enable interface $dev." 1>&2
 114  exit 1
 115fi
 116if [ "$ipaddr" = "" ]; then exit 0; fi
 117
 118if ! arping -q -c 2 -w 3 -D -I $dev $ipaddr ; then
 119  echo "Error: some host already uses address $ipaddr on $dev." 1>&2
 120  exit 1
 121fi
 122
 123if ! ip address add $pfx brd + dev $dev $label; then
 124  echo "Error: failed to add $pfx on $dev." 1>&2
 125  exit 1
 126fi
 127
 128arping -q -A -c 1 -I $dev $ipaddr
 129noarp=$?
 130( sleep 2 ;
 131  arping -q -U -c 1 -I $dev $ipaddr ) >/dev/null 2>&1 </dev/null &
 132
 133ip route add unreachable 224.0.0.0/24 >/dev/null 2>&1
 134ip route add unreachable 255.255.255.255 >/dev/null 2>&1
 135if [ "`ip link ls $dev | grep -c MULTICAST`" -ge 1 ]; then
 136  ip route add 224.0.0.0/4 dev $dev scope global >/dev/null 2>&1
 137fi
 138
 139if [ $fwd -eq 0 ]; then
 140  if [ $noarp -eq 0 ]; then
 141    ip ro append default dev $dev metric 30000 scope global
 142  elif [ "$peer" != "" ]; then
 143    if ping -q -c 2 -w 4 $peer ; then
 144      ip ro append default via $peer dev $dev metric 30001
 145    fi
 146  fi
 147  RestartRDISC
 148fi
 149
 150exit 0
 151