(→‎Cross Compiling Wide DHCPv6 for ARM)
(Added example configuration)
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== Flex: the fast lexical analyser ==
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== WideDHCP - A DHCPv6 Client == 
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Before an ISP will route your allocated IPv6 subnet, a lease needs to be acquired. This can be done using DHCPv6 over the PPP interface.
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Currently ISC-DHCP doesn't support the PPP interface.
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=== Flex: the fast lexical analyser ===
  
 
Flex is a dependency for Wide-DHCPv6. It requires the [https://www.gnu.org/software/m4/m4.html GNU M4] macro processor & texi2dvi installed on your build system:
 
Flex is a dependency for Wide-DHCPv6. It requires the [https://www.gnu.org/software/m4/m4.html GNU M4] macro processor & texi2dvi installed on your build system:
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</PRE>
 
</PRE>
  
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== Cross Compiling Wide DHCPv6 for ARM ==
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=== Cross Compiling Wide DHCPv6 for ARM ===
  
 
Wide-DHCPv6 has not been updated for some time and uses structures no longer avaliable in [http://sourceforge.net/tracker/index.php?func=detail&aid=2487489&group_id=153668&atid=788687 glibc without the use of the #define _GNU_SOURCE]
 
Wide-DHCPv6 has not been updated for some time and uses structures no longer avaliable in [http://sourceforge.net/tracker/index.php?func=detail&aid=2487489&group_id=153668&atid=788687 glibc without the use of the #define _GNU_SOURCE]
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./configure --prefix=/home/export/rootfs --host=arm-linux-gnueabi --with-localdbdir=/tmp ac_cv_func_setpgrp_void=yes ac_cv_lib_fl_yywrap=yes
 
./configure --prefix=/home/export/rootfs --host=arm-linux-gnueabi --with-localdbdir=/tmp ac_cv_func_setpgrp_void=yes ac_cv_lib_fl_yywrap=yes
 
make
 
make
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</PRE>
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=== Configuration ===
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Below is a sample dhcp6c.conf file:
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<PRE>
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interface ppp0 {
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    send ia-pd 0;
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    script "/etc/wide-dhcpv6/dhcp6c-script";
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};
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id-assoc pd {
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    prefix-interface eth0 {
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            sla-id 0;
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            sla-len 8;
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    };
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};
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</PRE>
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dhcp6c can be started using:
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<PRE>
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dhcp6c -c /etc/wide-dhcpv6/dhcp6c.conf ppp0
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</PRE>
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Please note that once IPv6 forwarding is enabled, linux will ignore subsequent DHCPv6 messages. This prevents your prefix lease being renewed and routing will stop. To prevent this, you need to allow unsolicited UDP traffic coming in on port 546.
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This can be achieved using the following ip6tables entry:
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<PRE>
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/sbin/ip6tables -A INPUT -m state --state NEW -m udp -p udp --dport 546 --sport 547 -s fe80::/10 -d fe80::/10 -j ACCEPT
 
</PRE>
 
</PRE>

Revision as of 09:44, 12 July 2014

WideDHCP - A DHCPv6 Client

Before an ISP will route your allocated IPv6 subnet, a lease needs to be acquired. This can be done using DHCPv6 over the PPP interface.

Currently ISC-DHCP doesn't support the PPP interface.

Flex: the fast lexical analyser

Flex is a dependency for Wide-DHCPv6. It requires the GNU M4 macro processor & texi2dvi installed on your build system: 

sudo apt-get install m4
sudo apt-get install texinfo
sudo apt-get install texlive

Download flex and cross compile for ARM assuming your ARM cross compiler is located at /opt/arm-2011.09/ 

wget http://sourceforge.net/projects/flex/files/flex-2.5.39.tar.bz2
tar -xjf flex-2.5.39.tar.bz2
cd flex-2.5.39/
./configure --host=arm-linux-gnueabi --prefix=/usr/arm-linux-gnueabi ac_cv_func_malloc_0_nonnull=yes ac_cv_func_realloc_0_nonnull=yes
make
make install

Cross Compiling Wide DHCPv6 for ARM

Wide-DHCPv6 has not been updated for some time and uses structures no longer avaliable in glibc without the use of the #define _GNU_SOURCE

Instead, we patch it with a patch developed by Jeremie Corbier 

wget http://downloads.sourceforge.net/project/wide-dhcpv6/wide-dhcpv6/wide-dhcpv6-20080615/wide-dhcpv6-20080615.tar.gz
wget http://wiki.beyondlogic.org/patches/wide-dhcpv6/0004-GNU-libc6-fixes.patch
tar -xzf wide-dhcpv6-20080615.tar.gz 
cd wide-dhcpv6-20080615/
patch -p1 < ../0004-GNU-libc6-fixes.patch 
./configure --prefix=/home/export/rootfs --host=arm-linux-gnueabi --with-localdbdir=/tmp ac_cv_func_setpgrp_void=yes ac_cv_lib_fl_yywrap=yes
make

Configuration

Below is a sample dhcp6c.conf file: 

interface ppp0 {
    send ia-pd 0;
    script "/etc/wide-dhcpv6/dhcp6c-script";
};

id-assoc pd {
    prefix-interface eth0 {
            sla-id 0;
            sla-len 8;
    };
};

dhcp6c can be started using: 

dhcp6c -c /etc/wide-dhcpv6/dhcp6c.conf ppp0

Please note that once IPv6 forwarding is enabled, linux will ignore subsequent DHCPv6 messages. This prevents your prefix lease being renewed and routing will stop. To prevent this, you need to allow unsolicited UDP traffic coming in on port 546.

This can be achieved using the following ip6tables entry: 

/sbin/ip6tables -A INPUT -m state --state NEW -m udp -p udp --dport 546 --sport 547 -s fe80::/10 -d fe80::/10 -j ACCEPT
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