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bastibasti
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Joined: 27 Nov 2006
Posts: 581
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 Posted: Tue Feb 07, 2017 6:58 am Post subject: Any way to provide network setting via kernel cmdline? |
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Hi,
Is there any way to provide network config via cmdline? for example eth0=192.168.1.10 etc??
Im using the stock network (net.lo) script |
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charles17
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Joined: 02 Mar 2008
Posts: 3664
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| Posted: Tue Feb 07, 2017 7:10 am Post subject: |
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| Try ifconfig or ip address. |
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cboldt
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Joined: 24 Aug 2005
Posts: 1046
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| Posted: Tue Feb 07, 2017 7:33 am Post subject: |
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Nothing in /usr/src/linux/Documentation/kernel-parameters.txt
But that file does refer the reader to driver files for network interface hardware. |
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eccerr0r
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Joined: 01 Jul 2004
Posts: 9679
Location: almost Mile High in the USA
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| Posted: Tue Feb 07, 2017 7:43 am Post subject: |
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There is a kernel option:
ip=ipaddress:optional_nfs_root_ipaddress:gateway_ipaddress:netmask:hostname:ether_device:off:dns0_addr:dns1_addr
so something like...
ip=124.22.114.26::124.22.114.1:255.255.255.0:myhostname:eth0:off:8.8.8.8:4.4.4.4
Note: this is a guess, I've never actually used it. Reference located in: $KERNEL/Documentation/filesystems/nfs/nfsroot.txt
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krinn
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Joined: 02 May 2003
Posts: 7470
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| Posted: Tue Feb 07, 2017 8:48 am Post subject: |
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as easy as
ifconfig eth0 192.168.0.4
route add default gw 192.168.0.100
or even easier "dhcpcd eth0" |
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khayyam
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Joined: 07 Jun 2012
Posts: 6227
Location: Room 101
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| Posted: Tue Feb 07, 2017 9:02 am Post subject: Re: Any way to provide network setting via kernel cmdline? |
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| bastibasti wrote: | | Is there any way to provide network config via cmdline? for example eth0=192.168.1.10 etc?? Im using the stock network (net.lo) script |
bastibasti ... basically all you need do is bring the interface up, add an ip/route, and configure dns resolution:
| Code: | # ip link set dev eth0 up
# ip addr add 192.168.1.10/24 brd + dev eth0
# ip route add default via 192.168.1.254
# echo "nameserver 192.168.1.254" >> /etc/resolv.conf |
However, this will not provide the 'net' target (because you're configuring network outside of openrc/netifrc), so should something 'need net' some service (ie, net.eth0, or dhcpcd) will be started that 'provide[s] net'. For that reason you are better off doing the following:
| /etc/conf.d/net: | config_eth0="192.168.1.10/24"
routes_eth0="default via 192.168.1.254" |
| Code: | # ln -s /etc/init.d/net.lo /etc/init.d/net.eth0
# /etc/init.d/net.eth0 start |
You might find net.eth0 is started automatically at boot, prehaps due to 'hotplug', or because some service in the 'default' runlevel 'need[s] net', if you don't want this (which, I assume is your reason for asking the above) you could do the following:
| /etc/rc.conf: | rc_dhcpcd_provide="!net"
rc_sshd_need="!net" |
EDIT: just re-read the subject line, so ignore the above. All you need to is tell init what runlevel it should start by adding 'softlevel=<runlevel>', and if 'net.eth0' is in that runlevel it will be started.
HTH & best ... khay
Last edited by khayyam on Tue Feb 07, 2017 9:09 am; edited 1 time in total |
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NeddySeagoon
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Joined: 05 Jul 2003
Posts: 54234
Location: 56N 3W
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| Posted: Tue Feb 07, 2017 9:05 am Post subject: |
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bastibasti,
What do you really want to do?
Tell us your problem rather than your perceived solution.
If you want to mount root over the network, for a diskless system, eccerr0r is pointing the way.
Check the syntax, its a long time since I've used it.
You still need to start networking with all the same parameters during boot or things that depend on networking won't start.
Then there is the network console. Its not secure, so don't use it over a hostile network.
You need a kernel option or two and its documented in /usr/scr/linux/Documentation
You still need to start networking normally too.
You can put anything you want on the kernel command line and parse it yourself out of /proc/cmdline.
Just make sure nothing else grabs it.
bastibasti_ip=
bastibasti_netmask=
and so on.
You need to write the script to parse /proc/cmdline and do whatever you want with it.
As a worked example, see how the init script deals with root=
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NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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bastibasti
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Joined: 27 Nov 2006
Posts: 581
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| Posted: Tue Feb 07, 2017 2:28 pm Post subject: |
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as stated in the thread title I'm talking about kernel cmdline, not bash
I know howto bring up the network on a console.
| Code: | You can put anything you want on the kernel command line and parse it yourself out of /proc/cmdline.
Just make sure nothing else grabs it.
bastibasti_ip=
bastibasti_netmask=
and so on. |
that was my intention. I wanted to know whether the stock rc scripts already include any functionality to parse the cmdline.
Seems like no. I use following script to run from rc.local
#netip_eth0=dhcp <- configure eth0 using dhcp
#netip_eth0=192.168.1.10,255.255.255.0,192.168.1.1,192.168.1.1
# dev IP MASK DefaultGW Nameserver
| Code: |
COMMANDLINE="/proc/cmdline"
##Get number of kernel arguments
num_args=$(awk '{print NF}' "$COMMANDLINE" | sort -nu | tail -n 1)
cmdline=$(cat "$COMMANDLINE")
#netip_eth0=192.168.1.10,255.255.255.0,192.168.1.1,192.168.1.1
#ip,mask,gw,nameserver
##Parse for settings
for ((coloumn=1;coloumn<=$num_args;coloumn++)); do
#get argument
arg=$(echo "$cmdline"|cut -f$coloumn -d ' ')
arg1=$(echo "$arg"|cut -f1 -d '=')
arg2=$(echo "$arg1"|cut -f1 -d '_')
if [ $arg2 == "netip" ]; then
interface=$(echo "$arg1"|cut -f2 -d '_')
val=$(echo "$arg"|cut -f2 -d '=')
ip=$(echo "$val"|cut -f1 -d ',')
mask=$(echo "$val"|cut -f2 -d ',')
gw=$(echo "$val"|cut -f3 -d ',')
nameserver=$(echo "$val"|cut -f4 -d ',')
if [ $ip == "dhcp" ]; then
echo "Network settings for ""$interface"" found in kernel command line."
echo "Calling DHCP, as requested"
dhcpcd "$interface"
fi
if [ $ip != "dhcp" ]; then
echo "Network settings for ""$interface"" found in kernel command line."
echo "Applying following settings:"
echo "IP: ""$ip"
echo "MASK: ""$mask"
echo "GATEWAY: ""$gw"
echo "NAMESERVER: ""$nameserver"
ifconfig "$interface" up
sleep 1
ifconfig "$interface" "$ip" netmask "$mask"
sleep 1
route add default gw "$gw"
echo "nameserver ""$nameserver" >>/etc/resolv.conf
fi
echo
fi
done
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khayyam
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Joined: 07 Jun 2012
Posts: 6227
Location: Room 101
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| Posted: Tue Feb 07, 2017 2:54 pm Post subject: |
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| bastibasti wrote: | | that was my intention. I wanted to know whether the stock rc scripts already include any functionality to parse the cmdline. Seems like no. |
bastibasti ... all you need do is create a runlevel, and provide 'softlevel=<runlevel>' on the kernel command line:
| Code: | # mkdir /etc/runlevels/online
# rc-update -s add default online # the '-s' for 'stacked' runlevel
# rc-update add net.eth0 online |
... and then as a kernel parameter: 'softlevel=online'.
best ... khay |
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bastibasti
Guru
Joined: 27 Nov 2006
Posts: 581
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| Posted: Tue Feb 07, 2017 3:04 pm Post subject: |
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mmhh maybe i do need to explain what this is for. Sorry. My mistake on trying to focus on the problem but when youre focussing on an issue you dont see that more info is needed.
The rootfs is a ramdisk I dont want to change to ramdisk for changing the network settings.
Instead want to edit the network setting from the boot loader. It uses openrc and gentoo as a base including all other scripts for booting. My script works nicely in the ramdisk now. All I thought was that I wanted to prevent using another script if this functionality was already included in the gentoo net.lo init script |
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NeddySeagoon
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Joined: 05 Jul 2003
Posts: 54234
Location: 56N 3W
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| Posted: Tue Feb 07, 2017 3:15 pm Post subject: |
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bastibasti,
The net.lo init script includes four hooks. Pre/Post UP and Pre/Post down.
They are documented at the end of /usr/share/doc/netifrc-*/net.example.bz2
I guess using preup is just a different way of doing what you are already doing.
_________________
Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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khayyam
Watchman
Joined: 07 Jun 2012
Posts: 6227
Location: Room 101
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| Posted: Tue Feb 07, 2017 3:31 pm Post subject: |
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| bastibasti wrote: | | The rootfs is a ramdisk I dont want to change to ramdisk for changing the network settings. Instead want to edit the network setting from the boot loader. It uses openrc and gentoo as a base including all other scripts for booting. My script works nicely in the ramdisk now. All I thought was that I wanted to prevent using another script if this functionality was already included in the gentoo net.lo init script |
bastibasti ... I see, the problem I see with this is that your script (run from local.d) will not 'provide net', you are better to use 'preup()' (in /etc/conf.d/net) and parse those values from /proc/cmdline to provide values for 'config_${IFACE}', etc.
best ... khay |
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