etc/network.subr

   1 #
   2 # Copyright (c) 2003 The FreeBSD Project. All rights reserved.
   3 #
   4 # Redistribution and use in source and binary forms, with or without
   5 # modification, are permitted provided that the following conditions
   6 # are met:
   7 # 1. Redistributions of source code must retain the above copyright
   8 #    notice, this list of conditions and the following disclaimer.
   9 # 2. Redistributions in binary form must reproduce the above copyright
  10 #    notice, this list of conditions and the following disclaimer in the
  11 #    documentation and/or other materials provided with the distribution.
  12 #
  13 # THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  14 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16 # ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  17 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23 # SUCH DAMAGE.
  24 #
  25 # $FreeBSD: src/etc/network.subr,v 1.163 2005/06/30 04:52:47 brooks Exp $
  26 # $DragonFly: src/etc/network.subr,v 1.5 2007/07/10 22:36:01 swildner Exp $
  27 #
  28
  29 #
  30 # Subroutines commonly used from network startup scripts.
  31 # Requires that rc.conf be loaded first.
  32 #
  33
  34 # ifconfig_up if
  35 #       Evaluate ifconfig(8) arguments for interface $if and
  36 #       run ifconfig(8) with those arguments. It returns 0 if
  37 #       arguments were found and executed or 1 if the interface
  38 #       had no arguments.  Pseudo arguments DHCP and WPA are handled
  39 #       here.
  40 #
  41 ifconfig_up()
  42 {
  43         _cfg=1
  44
  45         ifconfig_args=`ifconfig_getargs $1`
  46         if [ -n "${ifconfig_args}" ]; then
  47                 ifconfig $1 ${ifconfig_args}
  48                 _cfg=0
  49         fi
  50
  51         if wpaif $1; then
  52                 /etc/rc.d/wpa_supplicant start $1
  53                 _cfg=0          # XXX: not sure this should count
  54         fi
  55
  56         if dhcpif $1; then
  57                 /etc/rc.d/dhclient start $1
  58                 _cfg=0
  59         fi
  60
  61         return $_cfg
  62 }
  63
  64 # ifconfig_down if
  65 #       Remove all inet entries from the $if interface. It returns
  66 #       0 if inet entries were found and removed. It returns 1 if
  67 #       no entries were found or they could not be removed.
  68 #
  69 ifconfig_down()
  70 {
  71         [ -z "$1" ] && return 1
  72         _ifs="^"
  73         _cfg=1
  74
  75         inetList="`ifconfig $1 | grep 'inet ' | tr "\n" "$_ifs"`"
  76
  77         oldifs="$IFS"
  78         IFS="$_ifs"
  79         for _inet in $inetList ; do
  80                 # get rid of extraneous line
  81                 [ -z "$_inet" ] && break
  82
  83                 _inet=`expr "$_inet" : '.*\(inet \([0-9]\{1,3\}\.\)\{3\}[0-9]\{1,3\}\).*'`
  84
  85                 IFS="$oldifs"
  86                 ifconfig $1 ${_inet} delete
  87                 IFS="$_ifs"
  88                 _cfg=0
  89         done
  90         IFS="$oldifs"
  91
  92         if wpaif $1; then
  93                 /etc/rc.d/wpa_supplicant stop $1
  94         fi
  95
  96         if dhcpif $1; then
  97                 /etc/rc.d/dhclient stop $1
  98                 _cfg=0
  99         fi
 100
 101         return $_cfg
 102 }
 103
 104 # _ifconfig_getargs if
 105 #       Echos the arguments for the supplied interface to stdout.
 106 #       returns 1 if empty.  In general, ifconfig_getargs should be used
 107 #       outside this file.
 108 _ifconfig_getargs()
 109 {
 110         _ifn=$1
 111         if [ -z "$_ifn" ]; then
 112                 return 1
 113         fi
 114
 115         eval _args=\$ifconfig_$1
 116         if [ -z "$_args" -a -n "${pccard_ifconfig}" ]; then
 117                 for _if in ${removable_interfaces} ; do
 118                         if [ "$_if" = "$_ifn" ] ; then
 119                                 _args=${pccard_ifconfig}
 120                                 break
 121                         fi
 122                 done
 123         fi
 124
 125         echo $_args
 126 }
 127
 128 # ifconfig_getargs if
 129 #       Takes the result from _ifconfig_getargs and removes pseudo
 130 #       args such as DHCP and WPA.
 131 ifconfig_getargs()
 132 {
 133         _tmpargs=`_ifconfig_getargs $1`
 134         if [ $? -eq 1 ]; then
 135                 return 1
 136         fi
 137         _args=
 138
 139         for _arg in $_tmpargs; do
 140                 case $_arg in
 141                 [Dd][Hh][Cc][Pp])
 142                         ;;
 143                 [Ww][Pp][Aa])
 144                         ;;
 145                 *)
 146                         _args="$_args $_arg"
 147                         ;;
 148                 esac
 149         done
 150
 151         echo $_args
 152 }
 153
 154 # dhcpif if
 155 #       Returns 0 if the interface is a DHCP interface and 1 otherwise.
 156 dhcpif()
 157 {
 158         _tmpargs=`_ifconfig_getargs $1`
 159         for _arg in $_tmpargs; do
 160                 case $_arg in
 161                 [Dd][Hh][Cc][Pp])
 162                         return 0
 163                         ;;
 164                 esac
 165         done
 166         return 1
 167 }
 168
 169 # wpaif if
 170 #       Returns 0 if the interface is a WPA interface and 1 otherwise.
 171 wpaif()
 172 {
 173         _tmpargs=`_ifconfig_getargs $1`
 174         for _arg in $_tmpargs; do
 175                 case $_arg in
 176                 [Ww][Pp][Aa])
 177                         return 0
 178                         ;;
 179                 esac
 180         done
 181         return 1
 182 }
 183
 184 # ifalias_up if
 185 #       Configure aliases for network interface $if.
 186 #       It returns 0 if at least one alias was configured or
 187 #       1 if there were none.
 188 #
 189 ifalias_up()
 190 {
 191         _ret=1
 192         alias=0
 193         while : ; do
 194                 eval ifconfig_args=\$ifconfig_$1_alias${alias}
 195                 if [ -n "${ifconfig_args}" ]; then
 196                         ifconfig $1 ${ifconfig_args} alias
 197                         alias=$((${alias} + 1))
 198                         _ret=0
 199                 else
 200                         break
 201                 fi
 202         done
 203         return $_ret
 204 }
 205
 206 #ifalias_down if
 207 #       Remove aliases for network interface $if.
 208 #       It returns 0 if at least one alias was removed or
 209 #       1 if there were none.
 210 #
 211 ifalias_down()
 212 {
 213         _ret=1
 214         alias=0
 215         while : ; do
 216                 eval ifconfig_args=\$ifconfig_$1_alias${alias}
 217                 if [ -n "${ifconfig_args}" ]; then
 218                         ifconfig $1 ${ifconfig_args} -alias
 219                         alias=$((${alias} + 1))
 220                         _ret=0
 221                 else
 222                         break
 223                 fi
 224         done
 225         return $_ret
 226 }
 227
 228 # ifscript_up if
 229 #       Evaluate a startup script for the $if interface.
 230 #       It returns 0 if a script was found and processed or
 231 #       1 if no script was found.
 232 #
 233 ifscript_up()
 234 {
 235         if [ -r /etc/start_if.$1 ]; then
 236                 . /etc/start_if.$1
 237                 return 0
 238         fi
 239         return 1
 240 }
 241
 242 # ifscript_down if
 243 #       Evaluate a shutdown script for the $if interface.
 244 #       It returns 0 if a script was found and processed or
 245 #       1 if no script was found.
 246 #
 247 ifscript_down()
 248 {
 249         if [ -r /etc/stop_if.$1 ]; then
 250                 . /etc/stop_if.$1
 251                 return 0
 252         fi
 253         return 1
 254 }
 255
 256 # Create cloneable interfaces.
 257 #
 258 clone_up()
 259 {
 260         _prefix=
 261         _list=
 262         for ifn in ${cloned_interfaces}; do
 263                 ifconfig ${ifn} create
 264                 if [ $? -eq 0 ]; then
 265                         _list="${_list}${_prefix}${ifn}"
 266                         [ -z "$_prefix" ] && _prefix=' '
 267                 fi
 268         done
 269         debug "Cloned: ${_list}"
 270 }
 271
 272 # Destroy cloned interfaces. Destroyed interfaces are echoed
 273 # to standard output.
 274 #
 275 clone_down()
 276 {
 277         _prefix=
 278         _list=
 279         for ifn in ${cloned_interfaces}; do
 280                 ifconfig ${ifn} destroy
 281                 if [ $? -eq 0 ]; then
 282                         _list="${_list}${_prefix}${ifn}"
 283                         [ -z "$_prefix" ] && _prefix=' '
 284                 fi
 285         done
 286         debug "Destroyed clones: ${_list}"
 287 }
 288
 289 gif_up() {
 290         case ${gif_interfaces} in
 291         [Nn][Oo] | '')
 292                 ;;
 293         *)
 294                 for i in ${gif_interfaces}; do
 295                         eval peers=\$gifconfig_$i
 296                         case ${peers} in
 297                         '')
 298                                 continue
 299                                 ;;
 300                         *)
 301                                 ifconfig $i create >/dev/null 2>&1
 302                                 ifconfig $i tunnel ${peers}
 303                                 ifconfig $i up
 304                                 ;;
 305                         esac
 306                 done
 307                 ;;
 308         esac
 309 }
 310
 311 #
 312 # ipx_up ifn
 313 # Configure any IPX addresses for interface $ifn. Returns 0 if IPX
 314 # arguments were found and configured; returns 1 otherwise.
 315 #
 316 ipx_up()
 317 {
 318         ifn="$1"
 319         eval ifconfig_args=\$ifconfig_${ifn}_ipx
 320         if [ -n "${ifconfig_args}" ]; then
 321                 ifconfig ${ifn} ${ifconfig_args}
 322                 return 0
 323         fi
 324         return 1
 325 }
 326
 327 # ipx_down ifn
 328 #       Remove IPX addresses for interface $ifn. Returns 0 if IPX
 329 #       addresses were found and unconfigured. It returns 1, otherwise.
 330 #
 331 ipx_down()
 332 {
 333         [ -z "$1" ] && return 1
 334         _ifs="^"
 335         _ret=1
 336
 337         ipxList="`ifconfig $1 | grep 'ipx ' | tr "\n" "$_ifs"`"
 338
 339         oldifs="$IFS"
 340         IFS="$_ifs"
 341         for _ipx in $ipxList ; do
 342                 # get rid of extraneous line
 343                 [ -z "$_ipx" ] && break
 344
 345                 _ipx=`expr "$_ipx" : '.*\(ipx [0-9a-h]\{1,8\}H*\.[0-9a-h]\{1,12\}\).*'`
 346
 347                 IFS="$oldifs"
 348                 ifconfig $1 ${_ipx} delete
 349                 IFS="$_ifs"
 350                 _ret=0
 351         done
 352         IFS="$oldifs"
 353
 354         return $_ret
 355 }
 356
 357 # ifnet_rename
 358 #       Rename all requested interfaces.
 359 #
 360 ifnet_rename()
 361 {
 362
 363         _ifn_list="`ifconfig -l`"
 364         [ -z "$_ifn_list" ] && return 0
 365         for _if in ${_ifn_list} ; do
 366                 eval _ifname=\$ifconfig_${_if}_name
 367                 if [ ! -z "$_ifname" ]; then
 368                         ifconfig $_if name $_ifname
 369                 fi
 370         done
 371         return 0
 372 }
 373
 374 #
 375 # list_net_interfaces type
 376 #       List all network interfaces. The type of interface returned
 377 #       can be controlled by the type argument. The type
 378 #       argument can be any of the following:
 379 #               nodhcp - all interfaces, excluding DHCP configured interfaces
 380 #               dhcp   - list only DHCP configured interfaces
 381 #       If no argument is specified all network interfaces are output.
 382 #       Note that the list will include cloned interfaces if applicable.
 383 #       Cloned interfaces must already exist to have a chance to appear
 384 #       in the list if ${network_interfaces} is set to `auto'.
 385 #
 386 list_net_interfaces()
 387 {
 388         type=$1
 389
 390         # Get a list of ALL the interfaces.  NOTE: cloned interfaces
 391         # have already been configured so they should show up in the
 392         # ifconfig -l output.
 393         #
 394         case ${network_interfaces} in
 395         [Aa][Uu][Tt][Oo])
 396                 _tmplist="`ifconfig -l`"
 397                 ;;
 398         *)
 399                 _tmplist="${network_interfaces} ${cloned_interfaces}"
 400                 ;;
 401         esac
 402
 403         if [ -z "$type" ]; then
 404                 echo $_tmplist
 405                 return 0
 406         fi
 407
 408         # Separate out dhcp and non-dhcp interfaces
 409         #
 410         _aprefix=
 411         _bprefix=
 412         for _if in ${_tmplist} ; do
 413                 eval _ifarg="\$ifconfig_${_if}"
 414                 case "$_ifarg" in
 415                 [Dd][Hh][Cc][Pp])
 416                         _dhcplist="${_dhcplist}${_aprefix}${_if}"
 417                         [ -z "$_aprefix" ] && _aprefix=' '
 418                         ;;
 419                 ''|*)
 420                         _nodhcplist="${_nodhcplist}${_bprefix}${_if}"
 421                         [ -z "$_bprefix" ] && _bprefix=' '
 422                         ;;
 423                 esac
 424         done
 425
 426         case "$type" in
 427         nodhcp)
 428                 echo $_nodhcplist
 429                 ;;
 430         dhcp)
 431                 echo $_dhcplist
 432                 ;;
 433         esac
 434         return 0
 435 }
 436
 437 hexdigit()
 438 {
 439         if [ $1 -lt 10 ]; then
 440                 echo $1
 441         else
 442                 case $1 in
 443                 10)     echo a ;;
 444                 11)     echo b ;;
 445                 12)     echo c ;;
 446                 13)     echo d ;;
 447                 14)     echo e ;;
 448                 15)     echo f ;;
 449                 esac
 450         fi
 451 }
 452
 453 hexprint()
 454 {
 455         val=$1
 456         str=''
 457
 458         dig=`hexdigit $((${val} & 15))`
 459         str=${dig}${str}
 460         val=$((${val} >> 4))
 461         while [ ${val} -gt 0 ]; do
 462                 dig=`hexdigit $((${val} & 15))`
 463                 str=${dig}${str}
 464                 val=$((${val} >> 4))
 465         done
 466
 467         echo ${str}
 468 }
 469
 470 # Setup the interfaces for IPv6
 471 network6_interface_setup()
 472 {
 473         interfaces=$*
 474         rtsol_interfaces=''
 475         case ${ipv6_gateway_enable} in
 476         [Yy][Ee][Ss])
 477                 rtsol_available=no
 478                 ;;
 479         *)
 480                 rtsol_available=yes
 481                 ;;
 482         esac
 483         for i in $interfaces; do
 484                 rtsol_interface=yes
 485                 eval prefix=\$ipv6_prefix_$i
 486                 if [ -n "${prefix}" ]; then
 487                         rtsol_available=no
 488                         rtsol_interface=no
 489                         laddr=`network6_getladdr $i`
 490                         hostid=`expr "${laddr}" : 'fe80::\(.*\)%\(.*\)'`
 491                         for j in ${prefix}; do
 492                                 address=$j\:${hostid}
 493                                 ifconfig $i inet6 ${address} prefixlen 64 alias
 494
 495                                 case ${ipv6_gateway_enable} in
 496                                 [Yy][Ee][Ss])
 497                                         # subnet-router anycast address
 498                                         # (rfc2373)
 499                                         ifconfig $i inet6 $j:: prefixlen 64 \
 500                                                 alias anycast
 501                                         ;;
 502                                 esac
 503                         done
 504                 fi
 505                 eval ipv6_ifconfig=\$ipv6_ifconfig_$i
 506                 if [ -n "${ipv6_ifconfig}" ]; then
 507                         rtsol_available=no
 508                         rtsol_interface=no
 509                         ifconfig $i inet6 ${ipv6_ifconfig} alias
 510                 fi
 511
 512                 if [ ${rtsol_available} = yes -a ${rtsol_interface} = yes ]
 513                 then
 514                         case ${i} in
 515                         lo0|gif[0-9]*|stf[0-9]*|faith[0-9]*|lp[0-9]*|sl[0-9]*|tun[0-9]*)
 516                                 ;;
 517                         *)
 518                                 rtsol_interfaces="${rtsol_interfaces} ${i}"
 519                                 ;;
 520                         esac
 521                 else
 522                         ifconfig $i inet6
 523                 fi
 524         done
 525
 526         if [ ${rtsol_available} = yes -a -n "${rtsol_interfaces}" ]; then
 527                 # Act as endhost - automatically configured.
 528                 # You can configure only single interface, as
 529                 # specification assumes that autoconfigured host has
 530                 # single interface only.
 531                 sysctl net.inet6.ip6.accept_rtadv=1
 532                 set ${rtsol_interfaces}
 533                 ifconfig $1 up
 534                 rtsol $1
 535         fi
 536
 537         for i in $interfaces; do
 538                 alias=0
 539                 while : ; do
 540                         eval ipv6_ifconfig=\$ipv6_ifconfig_${i}_alias${alias}
 541                         if [ -z "${ipv6_ifconfig}" ]; then
 542                                 break;
 543                         fi
 544                         ifconfig $i inet6 ${ipv6_ifconfig} alias
 545                         alias=$((${alias} + 1))
 546                 done
 547         done
 548 }
 549
 550 # Setup IPv6 to IPv4 mapping
 551 network6_stf_setup()
 552 {
 553         case ${stf_interface_ipv4addr} in
 554         [Nn][Oo] | '')
 555                 ;;
 556         *)
 557                 # assign IPv6 addr and interface route for 6to4 interface
 558                 stf_prefixlen=$((16+${stf_interface_ipv4plen:-0}))
 559                 OIFS="$IFS"
 560                 IFS=".$IFS"
 561                 set ${stf_interface_ipv4addr}
 562                 IFS="$OIFS"
 563                 hexfrag1=`hexprint $(($1*256 + $2))`
 564                 hexfrag2=`hexprint $(($3*256 + $4))`
 565                 ipv4_in_hexformat="${hexfrag1}:${hexfrag2}"
 566                 case ${stf_interface_ipv6_ifid} in
 567                 [Aa][Uu][Tt][Oo] | '')
 568                         for i in ${ipv6_network_interfaces}; do
 569                                 laddr=`network6_getladdr ${i}`
 570                                 case ${laddr} in
 571                                 '')
 572                                         ;;
 573                                 *)
 574                                         break
 575                                         ;;
 576                                 esac
 577                         done
 578                         stf_interface_ipv6_ifid=`expr "${laddr}" : \
 579                                                       'fe80::\(.*\)%\(.*\)'`
 580                         case ${stf_interface_ipv6_ifid} in
 581                         '')
 582                                 stf_interface_ipv6_ifid=0:0:0:1
 583                                 ;;
 584                         esac
 585                         ;;
 586                 esac
 587                 ifconfig stf0 create >/dev/null 2>&1
 588                 ifconfig stf0 inet6 2002:${ipv4_in_hexformat}:${stf_interface_ipv6_slaid:-0}:${stf_interface_ipv6_ifid} \
 589                         prefixlen ${stf_prefixlen}
 590                 # disallow packets to malicious 6to4 prefix
 591                 route add -inet6 2002:e000:: -prefixlen 20 ::1 -reject
 592                 route add -inet6 2002:7f00:: -prefixlen 24 ::1 -reject
 593                 route add -inet6 2002:0000:: -prefixlen 24 ::1 -reject
 594                 route add -inet6 2002:ff00:: -prefixlen 24 ::1 -reject
 595                 ;;
 596         esac
 597 }
 598
 599 # Setup static routes
 600 network6_static_routes_setup()
 601 {
 602         # Set up any static routes.
 603         case ${ipv6_defaultrouter} in
 604         [Nn][Oo] | '')
 605                 ;;
 606         *)
 607                 ipv6_static_routes="default ${ipv6_static_routes}"
 608                 ipv6_route_default="default ${ipv6_defaultrouter}"
 609                 ;;
 610         esac
 611         case ${ipv6_static_routes} in
 612         [Nn][Oo] | '')
 613                 ;;
 614         *)
 615                 for i in ${ipv6_static_routes}; do
 616                         eval ipv6_route_args=\$ipv6_route_${i}
 617                         route add -inet6 ${ipv6_route_args}
 618                 done
 619                 ;;
 620         esac
 621 }
 622
 623 # Setup faith
 624 network6_faith_setup()
 625 {
 626         case ${ipv6_faith_prefix} in
 627         [Nn][Oo] | '')
 628                 ;;
 629         *)
 630                 sysctl net.inet6.ip6.keepfaith=1
 631                 ifconfig faith0 create >/dev/null 2>&1
 632                 ifconfig faith0 up
 633                 for prefix in ${ipv6_faith_prefix}; do
 634                         prefixlen=`expr "${prefix}" : ".*/\(.*\)"`
 635                         case ${prefixlen} in
 636                         '')
 637                                 prefixlen=96
 638                                 ;;
 639                         *)
 640                                 prefix=`expr "${prefix}" : \
 641                                              "\(.*\)/${prefixlen}"`
 642                                 ;;
 643                         esac
 644                         route add -inet6 ${prefix} -prefixlen ${prefixlen} ::1
 645                         route change -inet6 ${prefix} -prefixlen ${prefixlen} \
 646                                 -ifp faith0
 647                 done
 648                 ;;
 649         esac
 650 }
 651
 652 # Install the "default interface" to kernel, which will be used
 653 # as the default route when there's no router.
 654 network6_default_interface_setup()
 655 {
 656         # Choose IPv6 default interface if it is not clearly specified.
 657         case ${ipv6_default_interface} in
 658         '')
 659                 for i in ${ipv6_network_interfaces}; do
 660                         case $i in
 661                         lo0|faith[0-9]*)
 662                                 continue
 663                                 ;;
 664                         esac
 665                         laddr=`network6_getladdr $i exclude_tentative`
 666                         case ${laddr} in
 667                         '')
 668                                 ;;
 669                         *)
 670                                 ipv6_default_interface=$i
 671                                 break
 672                                 ;;
 673                         esac
 674                 done
 675                 ;;
 676         esac
 677
 678         # Disallow unicast packets without outgoing scope identifiers,
 679         # or route such packets to a "default" interface, if it is specified.
 680         route add -inet6 fe80:: -prefixlen 10 ::1 -reject
 681         case ${ipv6_default_interface} in
 682         [Nn][Oo] | '')
 683                 route add -inet6 ff02:: -prefixlen 16 ::1 -reject
 684                 ;;
 685         *)
 686                 laddr=`network6_getladdr ${ipv6_default_interface}`
 687                 route add -inet6 ff02:: ${laddr} -prefixlen 16 -interface \
 688                         -cloning
 689
 690                 # Disable installing the default interface with the
 691                 # case net.inet6.ip6.forwarding=0 and
 692                 # net.inet6.ip6.accept_rtadv=0, due to avoid conflict
 693                 # between the default router list and the manual
 694                 # configured default route.
 695                 case ${ipv6_gateway_enable} in
 696                 [Yy][Ee][Ss])
 697                         ;;
 698                 *)
 699                         if [ `sysctl -n net.inet6.ip6.accept_rtadv` -eq 1 ]
 700                         then
 701                                 ndp -I ${ipv6_default_interface}
 702                         fi
 703                         ;;
 704                 esac
 705                 ;;
 706         esac
 707 }
 708
 709 network6_getladdr()
 710 {
 711         ifconfig $1 2>/dev/null | while read proto addr rest; do
 712                 case ${proto} in
 713                 inet6)
 714                         case ${addr} in
 715                         fe80::*)
 716                                 if [ -z "$2" ]; then
 717                                         echo ${addr}
 718                                         return
 719                                 fi
 720                                 case ${rest} in
 721                                 *tentative*)
 722                                         continue
 723                                         ;;
 724                                 *)
 725                                         echo ${addr}
 726                                         return
 727                                 esac
 728                         esac
 729                 esac
 730         done
 731 }