Funtoo Linux Networking/pt-br

Esse documento explica como configurar suas configurações de rede ao explicar a funcionalidade de configuração de rede (network configuration functionality) disponível no Funtoo Linux. Também está coberto aqui sobre configuração dhcpcd 5.x, Wi-Fi (IEEE 802.11), e o framework OpenResolv.

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Apresentação

Funtoo Linux possui seu próprio sistema central de (core network configuration system) que difere um pouco de sistemas de configuração de rede utilizado em Gentoo Linux e em OpenRC.

Nessa documentação, explicarei as únicas adições e alterações no Funtoo network configuration e mostrar como utilizar o sistema para configurar sua rede.

Também explicarei como utilizar o dhcpcd para gerenciar interfaces de rede em redes baseadas em DHCP, e também cobrirei a configuração do OpenRC stacked runlevel configuration, configuração Wi-Fi (IEEE 802.11), e o framework OpenResolv, que é habilitado no Funtoo Linux por padrão.

Uma breve apresentação ao Funtoo Network Configuration

Antes que eu entre em detalhes técnicos de configurar sua rede, é importante entender que o Funtoo Linux possui um número de opções diferentes disponíveis para que você configure a rede, como ainda mais recursos a serem adicionados no futuro. Cada approach é diferente e possui suas próprias forças e fraquezas, e isso, na minha opinião, uma boa coisa.

O Jeito (Dinâmico) Fácil

Quando configurar sua rede, uma opção é pular a configuração de rede tradicional e simplesmente contar depender do DHCP. Esse é de longe o método mais simples de configurar sua rede. Se você estiver em uma rede cabeada, outros passos não são tipicamente exigidos além de habilitar um DHCP client, e o Funtoo Linux inclui dhcpcd 6.x por padrão.

Network Manager, Wicd

Se caso você for utilizar um pacote third party tal qual Network Manager ou Wicd para gerenciar sua rede, então você não precisa configurar DHCP de modo algum. Esses pacotes configuram DHCP para você. Simplesmente execute um emerge no pacote que você quer utilizar e comece a utilizá-lo.

DHCP-Only Systems

Se você não estiver planejando utilizar um pacote third-party para gerenciar suas interfaces de rede, é ainda extremamente fácil configurar rede DHCP, especialmente se você sempre utiliza DHCP para conectar às redes, que é comum para desktops ou laptops. Nesse cenário, podemos simplesmente habilitar dhcpcd para ser executado na inicialização do sistema (system startup). Ele será executado em plano de fundo e automaticamente procurará por servidores DHCP em toda a suas interfaces de rede, e tentará to gerar o enlace de um endereço IP a partir de quaisquer servidor DHCP encontrado.

Se isso soa como o que vocẽ quer fazer, então adicione dhcpcd á suas runlevel padrões como a seguir:

root # rc-update add dhcpcd default

Para habilitar o DHCP imediatamente, você seguiria o comando anterior com um comando rc, que iniciaria o cliente dhcpcd que você acabou de adicionar:

root # rc

Se você estiver em uma rede cabeada e os drivers necessários no seu kernel, então isso deve bastar para você. Para redes sem fio, mois passos são necessários para para utilizar seu hardware de rede sem fio para assim associá-lo a um access point, que terá uma cobertura mais adiante nessa documentação.

Tweaking Dhcpcd

Por hora, é importante notar que o dhcpcd 6.x gerenciará todas as interfaces de rede disponíveis por padrão. Se você quiser executar um cliente DHCP em todas, menos uma interface, ou alguma outra subset de interfaces, você pode adicionar a denyinterfaces apropriada ou allowinterfaces glob pattern no /etc/dhcpcd.conf:

# manage all interfaces but eth0 with dhcpcd (gerencia todas as interfaces, exceto a eth0 com o dhcpcd)
denyinterfaces eth0

Isso pode ser realizado também ao modificar /etc/init.d/dhcpcd diretamente e adicionar -Z ifglob ou -z ifglob (os parâmetros equivalentes para comando) em command_args.

Utilizando os scripts Funtoo para o DHCP

Você pode também utilizar o Funtoo Linux networking scripts para iniciar um cliente DHCP apenas em uma interface específica. Esse acesso é melhor se você está planejando também fazer algum bridging avançado, bonding ou configuração VLAN em sua máquina com o DHCP, já que você estará utilizando o Funtoo Linux networking scripts para isso também.

Para utilizar esse acesso variante, não habilite /etc/init.d/dhcpcd diretamente. Ao invés disso, utilize o Funtoo Linux dhcpcd template que iniciará o dhcpcd em uma única interface. Abaixo, você verá os passos para fazer isso. Isso é muito similar a como realizamos configurações avançadas de interfaces de rede, que cobriremos mais adiante nessa documentação:

root # cd /etc/init.d
root # ln -s netif.tmpl netif.eth0
root # rc-update add netif.eth0 default
root # echo template=dhcpcd > /etc/conf.d/netif.eth0
root # rc

O último comando, rc, faz com que o netif.eth0 seja habilitada.

Server Network Configuration

For servers and advanced networking scenarios, Funtoo Linux offers its own modular, template-based network configuration system. This system offers a lot of flexibility for configuring network interfaces, essentially serving as a "network interface construction kit." This system can be used by itself, or even combined with dhcpcd, as shown in the previous section.

Here are the key components of the template-based network configuration system:

/etc/init.d/netif.lo

An init script that configures the localhost interface. This script is always enabled and is part of the boot process.

/etc/netif.d

This is a directory that contains various network configuration templates. Each of these templates is focused on configuring a particular type of network interface, such as a general static IP-based interface, a bridge interface, a bond interface, etc.

/etc/init.d/netif.tmpl

This is the master init script for the template-based network configuration system. New interfaces are added to your system by creating symbolic links to this file in /etc/init.d.

So, if you wanted to use this system to configure eth0 with a static IP address, you would create a netif.eth0 symlink to netif.tmpl as follows:

root # cd /etc/init.d
root # ln -s netif.tmpl netif.eth0

Then, you would create an /etc/conf.d/netif.eth0 configuration file that would specify which template to use from the /etc/netif.d directory:

template="interface"
ipaddr="10.0.1.200/24"
gateway="10.0.1.1"
nameservers="10.0.1.1 10.0.1.2"
domain="funtoo.org"

To complete our static IP network configuration we would need to:

root # rc-update add netif.eth0 default

When configuring your own static network interface, one of ipaddr or ipaddrs is required and should specify the IP address(es) to configure for this interface, in "a.b.c.d/netmask" format. Optional parameters include gateway, which defines a default gateway for your entire network, and if set should specify the gateway's IP address. In addition, domain and nameservers (space-separated if more than one) can be used to specify DNS information for this interface.

Configuration Variables

Interface Variables

The ipaddr and ipaddrs variables are supported by the interface and bridge templates, and are used to specify a single or multiple IPv4 or IPv6 address(es) for the interface. IP addresses should be specified in 'IP/netmask' format, such as 10.0.0.1/24. Multiple IP addresses can be specified delimited by whitespace:

ipaddrs="10.0.0.1/24 10.0.0.2/24"

Broadcast Address

By default, a broadcast address will be calculated based on the IP address and network mask. If you need to manually specify a broadcast address, use the following format for your IP address:

ipaddrs="10.0.0.1/24;broadcast=10.0.1.255 10.0.0.2/24"

Not Specifying An Address

Note that in some cases, you may choose to not specify ipaddr or ipaddrs for a bridge template. That is allowed. If you don't want to specify an IP address for a regular interface, you can choose to use the interface template without an IP address specified in the config, or use the interface-noip template instead, for the sake of clarity.

Viewing All Configured IP Addresses

Also note that if you specify multiple IPv4 addresses, ifconfig will only show the first IP address. To view all IP addresses associated with the interface, use the ip addr show command.

General Variables

The following variables are enabled by default for all network scripts, and if specified will trigger a corresponding configuration action:

nameservers

Set DNS nameservers using OpenResolv. Specify multiple IPv4 or IPv6 nameservers like this: "1.2.3.4 1.2.3.5 1.2.3.6". Please note that OpenResolv treats 127.0.0.1 specially, and it indicates that you are running a local name resolver like dnsmasq or bind. OpenResolv will ignore all other name servers specified alongside 127.0.0.1. See man resolvconf and man resolvconf.conf for additional setup information.

search

Set DNS search information using OpenResolv.

domain

Set DNS domain using OpenResolv.

gateway

Define a default IPv4 gateway on this interface.

gateway6

Define a default IPv6 gateway on this interface.

route

Specify a semi-colon delimited list of IPv4 routes to apply when this interface is brought up. Will be appended to ip -4 route add.

route6

Specify a semi-colon delimited list of IPv6 routes to apply when this interface is brought up. Will be appended to ip -6 route add.

mtu

Set Maximum Transmit Unit for the interface

mac_replace

Replace existing MAC address with MAC address specified in this variable.

VLAN Variables

VLAN support is enabled by default for all network configuration scripts. If a network script has a name in the format netif.ethX.Y, then it is assumed to be a VLAN interface referencing trunk ethX and VLAN ID Y. If you desire a custom name for your VLAN interface, you can name your interface whatever you'd like and specify the following variables in your interface config:

trunk

VLAN trunk interface, e.g. "eth0"

vlan

VLAN id, e.g. "32"

Bridge / Tap Variables

The following variables for configuring a functional bridge interface with optional tap interfaces:

slaves

Set slave interfaces of this interface (for bridges, etc.) All slaves will automatically be depended upon, and will also automatically have their mtu set to that of the current interface, if an mtu is specified for the current interface. This setting is required for the bond template and optional for the bridge template.

stp

Enables Spanning Tree Protocol on a bridge interface like this "stp=on"

forwarding

Enables forwarding on a bridge interface by calling sysctl; as this interface does not exist when sysctl is called by init, we do it here. If this is disabled, your bridge will not forward traffic back out onto the network. useage: "forwarding=1"

OpenResolv and resolv.conf

OpenResolv will be used to set DNS information provided by the nameservers, domain and search variables when an interface is brought up. The OpenResolv framework will add entries to /etc/resolv.conf, and will also handle removing these entries when the interface is brought down. This way, /etc/resolv.conf should always contain current information and should not need to be manually edited by the system administrator. dhcpcd will use OpenResolv for updating system DNS information as well.

Network-Dependent Services

One important difference between Gentoo Linux and Funtoo Linux is that, in Funtoo Linux, network-dependent services only strictly depend on netif.lo. This means that if another network service requires an interface to be up, such as samba requiring eth0, then the system administrator must specify this relationship by adding the following line to /etc/conf.d/samba:

rc_need="netif.eth0"

This will have the effect of ensuring that netif.eth0 is started prior to samba and that samba is stopped prior to stopping netif.eth0.

Many network services, especially those that listen on all network intefaces, don't need an rc_need line in order to function properly. Avoiding the use of rc_need when required will optimize boot times and allow more network services to remain available when network interfaces are brought up and down by the system administrator.

Multiple Network Configurations

For information on how to have multiple, independent network configurations, please see Stacked Runlevels.

Alternate Configs

If you need to run the same service with different configuration parameters depending upon runlevel, then you'll be happy to know that you can specify runlevel-specific conf.d files by appending a . <runlevel> suffix. In this particular example, we could imagine a situation where we had two child runlevels named home and work:

/etc/conf.d/netif.eth0.home
/etc/conf.d/netif.eth0.work

Note that this feature works for all init scripts, not just network configuration scripts.

Interface Renaming

Funtoo network scripts now support interface renaming, so you can create an interface called lan if you would like. To do this, simply specify the MAC address of the interface you would like to rename using the macaddr variable:

macaddr="00:15:17:19:b6:a3"

If this MAC address is part of the netif.lan configuration file, then when this interface starts, whatever interface currently has the MAC address of 00:15:17:19:b6:a3 (i.e. eth5) will be renamed to lan prior to the interface being brought up, and will show up in ifconfig and ip commands as being an interface named lan. It is possible to combine this with the mac_replace variable to set a new MAC address, if desired.

Basic VLAN Configuration

The standard interface template supports VLANs. To use VLAN support, first ensure that your kernel was compiled with VLAN support (the module name is 8021q) :

root # grep CONFIG_VLAN /usr/src/linux/.config
CONFIG_VLAN_8021Q=m
CONFIG_VLAN_8021Q_GVRP=y

Then, configure the trunk interface using the interface-noip template. Assuming eth1 is trunked, you would create the file /etc/conf.d/netif.eth1 with the following contents:

template="interface-noip"

Then, create a network interface symlink for the trunk and add it to your default runlevel:

root # cd /etc/init.d
root # ln -s netif.tmpl netif.eth1
root # rc-update add netif.eth1 default

Now, assuming you wanted to configure a VLAN of 32, you would create a config file named /etc/conf.d/netif.eth1.32 that looks something like this:

template="interface"
ipaddr="1.2.3.4/24"
gateway="1.2.3.1"# etc...

Then, create a VLAN network interface symlink and add it to your default runlevel:

root # cd /etc/init.d
root # ln -s netif.tmpl netif.eth1.32
root # rc-update add netif.eth1.32 default

The Funtoo network configuration scripts will automatically recognize the filename netif.eth1.32 as being VLAN 32 of trunk interface netif.eth1.

When the VLAN interface is brought up, it will be named eth1.32.

Custom VLAN Names

However, sometimes you may want to turn off automatic file-based VLAN naming and give your VLAN interface a custom name, such as mgmt. To do this, you would set up the trunk interface in the exact same way as described above, but instead of creating a netif.eth1.32 interface, you would create a netif.mgmt interface, and specify vlan and trunk in the /etc/conf.d/netif.mgmt config file, as follows:

template="interface"
vlan="32"
trunk="eth1"
ipaddr="1.2.3.4/24"
gateway="1.2.3.1"
# etc...

When you specify trunk and vlan in the interface config file, filename-based auto-detecting of VLAN ID and trunk is disabled. Both trunk and vlan must be specified -- you can't specify just one.

Then you would simply create a VLAN network interface symlink for netif.mgmt:

root # cd /etc/init.d
root # ln -s netif.tmpl netif.mgmt
root # rc-update add netif.mgmt default

When the VLAN interface is brought up, it will be named mgmt.

Bonding Configuration

Bonding allows you to aggregate multiple network interfaces into a single logical network interface, allowing for benefits in throughput as well as resiliency in the case that an individual interface may go down. This example shows how you would create a bonding interface (mybond) with a simple static ip setup, containing two slave devices (eth0 and eth1).

First, ensure that your kernel is configured to support bonding (the module name is bonding) :

user $ grep CONFIG_BONDING /usr/src/linux/.config
CONFIG_BONDING=m

You'l want to ensure that CONFIG_BONDING is set to "m" or "y". You can find this kernel configuration option tucked under "Device Drivers" -> "Network Device Support" -> "Bonding driver support". Be sure that ifenslave is emerged (this package included in Funtoo stage3):

root # emerge ifenslave

Once bonding is enabled in the kernel, you will need to choose at least two devices to bond together. These will be set up as "slave" interfaces with no IP address.

root # cd /etc/init.d/
root # ln -s netif.tmpl netif.eth0
root # ln -s netif.tmpl netif.eth1

Then, configure the slave interfaces by creating /etc/conf.d/netif.eth0 and /etc/conf.d/netif.eth1 with the following contents:

template="interface-noip"

Now, we will create the bond interface and make netif.eth0 and netif.eth1 slaves of this interface. Note that our bond interface can have any name. To demonstrate this, we will give it the name of "mybond" below:

root # ln -s netif.tmpl netif.mybond
root # rc-update add netif.mybond default

Now we can configure "mybond" using its configuration file /etc/conf.d/netif.mybond, just as we would a regular interface, except that we specify slaves:

template="bond"
ipaddr="10.0.1.200/24"
gateway="10.0.1.1"
nameservers="10.0.1.1 10.0.1.2"
domain="funtoo.org"
slaves="netif.eth0 netif.eth1"

In a bonded configuration, it is common to set the MTU to the maximum possible value supported by hardware to maximize throughput. In order to do this, simply set the MTU option in /etc/conf.d/netif.mybond to the maximum value supported by your hardware. The network scripts will ensure that this MTU setting is applied to all slave interfaces:

mtu=9000

Bridge Configuration

When hosting virtual machines, it can be convenient to use a bridge setup. This example shows how you would create a bridge (br0) with a simple static ip setup, containing two slave devices (eth0, tap0).

First, ensure that your kernel is configured to support bridging (the module name is bridge) :

user $ grep CONFIG_BRIDGE /usr/src/linux/.config
CONFIG_BRIDGE=m
CONFIG_BRIDGE_IGMP_SNOOPING=y

Second, make sure you have the required software installed:

root # emerge -av bridge-utils usermode-utilities

Then, create the necessary symlinks for the interfaces and add them to your default runlevel :

root # cd /etc/init.d/
root # ln -s netif.tmpl netif.eth0
root # ln -s netif.tmpl netif.br0
root # ln -s netif.tmpl netif.tap0
root # rc-update add netif.br0 default
root # rc-update add netif.tap0 default

Then, configure the slave interface /etc/conf.d/netif.eth0 :

template="interface-noip"

Then, configure the slave interface /etc/conf.d/netif.tap0 - note you only require group OR user, not both :

template="tap"
group="kvm" 
user="kvm"
mac_addr="10:20:30:40:50:66"

... and the bridge interface /etc/conf.d/netif.br0 :

template="bridge"
ipaddr="10.0.1.200/24"
gateway="10.0.1.1"
nameservers="10.0.1.1 10.0.1.2"
domain="funtoo.org"
slaves="netif.eth0 netif.tap0"
stp="on"
forwarding=1

If you are using dhcpcd, you should ensure that it does not attempt to configure eth0 or br0 by adding the following to /etc/dhcpcd.conf :

# don't attempt to pull an ip address for br0 or its slave device
denyinterfaces eth0 br0

More Complex Network Configuration

If the standard templates don't work for your needs, simply create a new template -- I recommend starting from the interface template for most things:

root # cd /etc/netif.d
root # cp interface custom

You can now call whatever commands you need to /etc/netif.d/custom. The following shell functions can be defined in a network script:

netif_create

In netif_create, you should call any commands to create the interface if it does not yet exist.

netif_depend

In netif_depend, you can define dependencies, using the functions need and use.

netif_pre_up

In netif_pre_up, you can define network configuration actions to perform prior to bringing the interface up. You can also ensure certain variables are specified by calling require var1 [var2...] here.

netif_post_up

In netif_post_up, you can define network configuration actions to perform after bringing the interface up.

netif_pre_down

In netif_pre_down, you can define network configuration actions to perform prior to bringing the interface down.

netif_post_down

In netif_post_down, you can define network configuration actions to perform after bringing the interface down.

netif_destroy

In netif_destroy, you can call any commands necessary to destroy/delete the interface if it is dynamic in nature (tun/tap, etc.)

How It Works

You do not specify a function for actually bringing up the interface, because the template-based system does this for you. The template-based system also performs all normal actions required to bring an interface down, so you only need to specify atypical actions that must be performed - such as removing child interfaces or destroying a bridge using brctl.

When you create your own network configuration template, the following capabilities are available for use automatically, as long as the appropriate variables are set in the /etc/conf.d/netif.<ifname> file, without requiring any explicit steps on your part:

• DNS configuration using domain and nameservers config settings. OpenResolv is used automatically.
• VLAN configuration using auto-naming (netif.ethX.Y) or via custom naming with trunk and vlan config settings.
• Default IPv4 gateway and route configuration using the gateway and route settings.
• Default IPv6 gateway and route configuration using the gateway6 and route6 settings.
• MTU configuration using the mtu setting.
• Auto-depend (and auto-MTU configuration) of slave interfaces specified using slaves setting.
• Renaming of existing network interface (specify MAC address using macaddr setting).

To take advantage of this functionality, simply enable the appropriate variables.

All other necessary network configuration and dependency behavior should be defined using the netif_-prefix functions described above.

Wireless Configuration

The recommended approach for setting up Wi-Fi under Funtoo Linux is to use NetworkManager. Steps are provided in the Wi-Fi section of the Funtoo Linux Installation Guide.

Other Network Configurations

If you have a network configuration template that might be useful to others, please post it to the funtoo-dev mailing list so we can review it and possibly incorporate it into Funtoo.

License

Funtoo Linux networking scripts are released under the following license:

Template:BSD2 Funtoo