Bifrost-under-the-hood-part1-FAQ

Contents

[1] Bifrost-under-the-hood-part1-FAQ

[1.1] The First boot

[1.2] The boot process

[1.3] How to toggle write protect of flash media

[1.4] Choice of editor

[1.5] Configuration files /etc/config.flags /etc/config.data

[1.6] How to configure IP4/IP6 addresses etc

[1.7] How do I connect to the router?

[1.8] How do I access the routing daemons?

[1.9] Access filter aka netfilter and stuff

[1.10] Loading network drivers that's not found autmaicaly

[1.11] Loading device drivers that's not found autmaticaly

[1.12] Virtual consoles

[1.13] Writing bifrost distro with dd or cp?

[1.14] Multiqueue capable cards/drivers

[1.15] eth-affinity

[1.16] Driver link flowcontrol

[1.17] Profiling of system and kernel

[1.18] Idea and anatomy of a bifrost package

[1.19] Building apps for bifrost

[1.20] Bifrost kernel configuration

[1.21] Rebuild a bifrost kernel

[1.22] Network monitoring

[1.23] 32 vs 64 bits

[1.24] ipv6 enabling

[1.25] Optical monitoring´╗┐

[1.26] TCAM filters etc for SUN Neptune card/driver

The First boot

The first boot triggers the configure script to run. The major purpose of this is to get some initial configuration.  IP address, and sshd  running.  So you can reach the system to configure the desired functionality.The configuration process creates  /etc/.configured file  when configured.

The boot process

Bifrost/Linux uses grub in most cases. grub  controls via /boot/grub/menu.lst which kernel to use and also different options. Please refer to grub info for further info.  After kernel boot

/bin/init  is run which uses /etc/inittab like most unix systems. The rc.* files are kept at minimum and  has a very simple and straightforward  design. Major files are rc.S, rc.M and rc.inet. User should avoid making changes in rc.* files.

How to toggle write protect of flash media

Bifrost uses remount r/w to avoid unintended writing flash media. Flash media limited lifetime for writing. remount w makes it writeable. To store configuration changes etc.  It's good idea to do remount r when configuration is done. Note! Ramdisk is always writable for scp etc.

Choice of editor

The editor is your tool for doing configuration and other work. Bifrost 6.0  and later includes vi, zile (a small powerful emacs clone) and nano.

Configuration files /etc/config.flags /etc/config.data

This two directories are controlling some of the major functions your in bifrost system. Many of the files in /etc/config.flags just controls if an option is enabled or not.  Check out these two directories.

How to configure IP4/IP6 addresses etc

It's recommended that you keep your IP-addresses in /etc/config.data/  For eth0  the config will be eth0.nic and so on.

How do I connect to the router?

ssh in most cases.

How do I access the routing daemons?

When using quagga. ssh into the Bifrost box. telnet localhost 2601 to get you into quagga daemon, Port number for ospfd is 2604,  bgpd 2606 and ospf6d 2606. As you know quagga has Cisco-like API. Of course make the flash diskwritable so you can store the config.

Access filter aka netfilter and stuff

In Bifrost/Linux files are kept under /filter look for  fwrules and  fw6rules which are run  at boot from rc.inet.

Loading network drivers that's not found autmaicaly

eth-detect should load proper network device drivers in most cases. Supporting files is located in  /etc/eth-detect.d/ and here the user should add own files if needed.

Loading device drivers that's not found autmaticaly

In most cases the system should load proper device drivers.  Supporting files is located in  /etc/device-detect.d/ and here user should add own files if needed.  For example modules for an own hard disk can be loaded here.

Virtual consoles

This Linux feature can be handy if you're configuring your system from the console.

http://lowfatlinux.com/linux-virtual-console.html

Writing bifrost distro with dd or cp?

Yes we try to support this now. Check out the download area for images.

Multiqueue capable cards/drivers

Bifrost is probably the first Linux distribution to support multi-queue and multi-core functionality in the Linux kernel. The idea is to use the virtualization support to boost the network and forwarding performance. The drivers ixgbe (Intel 10g card) and niu (SUN Neptune  board 10g and GIGE )  and igb  supports this.

eth-affinity

This is new utility to setup interrupt vectors etc. This is to support multi-queue cards. This is done automatic at boot when interfaces are brought up.

Driver link flowcontrol

For major drivers we turn this off by default.

Profiling of system and kernel

For research and very advanced users it should be possible to oprofile a running installation at very low cost. You need an optional package for this.  ftp://robur.slu.se/pub/Linux/bifrost/opt-x86_64/oprofile-090115-x86_64.tar.gz The major script is /opt/oprofile/bin/OP. Hint. If profiling  is not planned the /boot/vmlinux can be removed to save space.

Idea and anatomy of a bifrost package

A compressed tar archive that lives under /opt with pre and post-installation scripts (bash) .

/opt/pkg-name/                                              Main directory

/opt/pkg-name/etc/config.flags/pkg-name    Should contain "yes" to enable.

/opt/pkg-name/rc.d/rc.pkg-name                   Start script for package (called w. start argument)

Ideally the binaries are linked statically or with ulibc or diet-libc.

Building apps for bifrost

Bifrost kernel configuration

On a running system it can be captures  /proc/config.gz  otherwise look in /Documentation directory.

Rebuild a bifrost kernel

Network monitoring

Useful utilities  are rtstat, ifstat2

32 vs 64 bits

The current Bifrost 6.0 kernel is compiled for 64 bits but does include the option to run 32 binary programs. This works well for most programs with a few exceptions like  ethtool, tcpdump and strace.  These binaries are kept in /usr/bin64. The PATH should be automatically set correctly at boot.

ipv6 enabling

When enabling remember to change default policy in  /filter/fw6rules. Default is DROP.

Optical monitoring´╗┐

Not currently.  DOM and XFP can support this via the i2C bus on the tranceiver. But it seems that the I2C bus is not currently connected to the interface boards, this goes for the boards we've seen so far.

TCAM filters etc for SUN Neptune card/driver

The SUN Netpune board has HW classification support via programable TCAM. Drop filters data and control plane separation and new features should be possible. Programming is done via ethtool. This is in a very early stage and should be considered very experimental. Also there is byte-order bug when writing IP-address and port numbers.