Repository : ssh://git@open-mesh.org/doc

On branches: backup-redmine/2019-11-07,master

commit b60ee36d5402da3b2bd2b54d0b1f66fbc908053b Author: Sven Eckelmann sven@narfation.org Date: Sun Oct 27 13:32:53 2019 +0000

doc: open-mesh/OpenWrt_in_QEMU

b60ee36d5402da3b2bd2b54d0b1f66fbc908053b open-mesh/OpenWrt_in_QEMU.textile | 66 +++++++++++++++++++++++++++++---------- 1 file changed, 49 insertions(+), 17 deletions(-)

diff --git a/open-mesh/OpenWrt_in_QEMU.textile b/open-mesh/OpenWrt_in_QEMU.textile index 637ce82..7d83cd7 100644 --- a/open-mesh/OpenWrt_in_QEMU.textile +++ b/open-mesh/OpenWrt_in_QEMU.textile @@ -1,13 +1,37 @@ h1. OpenWrt in QEMU

-The [[open-mesh:Emulation_Environment#Architecture]] +The [[open-mesh:Emulation Environment#Architecture|simple emulation architecture]] can be implemented rather easily using qemu and an x86_64 image from OpenWrt. + +h2. OpenWrt preparation + +It is possible to just use an x86_64 which was "downloaded from OpenWrt's servers":https://downloads.openwrt.org/snapshots/targets/x86/64/openwrt-x86-64-combin.... But it is highly recommended to build an own image which: + +* enables the routing protocols (like batman-adv) from the "openwrt-routing feed":https://git.openwrt.org/?p=feed/routing.git;a=summary. +* enables the 9p filesystem (and virtio) +* integrates its own startup scripts (for automatic test initialization and shared path support) via <code>files/etc/rc.local</code> <pre><code class="shell"> +mkdir -p files/etc/ +cat > files/etc/rc.local << "EOF" +#!/bin/sh + +mkdir -p /host +mount -t 9p host /host +[ ! -x /host/test-init.sh ] || /host/test-init.sh +EOF +</code></pre> + +The shared is a folder from the host system which is mapped into all virtual instances. It can be used exchange data between the instances and the host. + +The resulting openwrt-x86-64-combined-ext4.img.gz has to be extracted and copies to the path with the other scripts. +

h2. Start of the simple environment

-The two node environment must be started inside a screen session. The hub (bridge with 5 tap devices) has to be started first to have a simple network. A more complex network setup can be on the page [[vde switch interconnect]] and [[bridge interconnect]] +h3. interconnect initialization

-<pre> -cat > hub.sh << "EOF" +The interconnect (bridge with 3 tap devices) has to be started first to have a simple network. All devices in this interconnect can talk to each other - which is not optimal for tests but enough for a start. More complex network setups can be on the pages [[vde switch interconnect]] and [[bridge interconnect]] + +<pre><code class="shell"> +cat > interconnect.sh << "EOF" #! /bin/sh

USER="$(whoami)" @@ -25,12 +49,16 @@ sudo ip link set "${BRIDGE}" up sudo ip addr replace 192.168.251.1/24 dev "${BRIDGE}" EOF

-chmod +x hub.sh -</pre> +chmod +x interconnect.sh +</code></pre> + +h3. VM instances bringup

-The @SHARED_PATH@ in run.sh has to be changed to a valid path which is used to share the precompiled batman-adv.ko and other tools +The three node environment must be started inside a screen session.

-<pre> +The @SHARED_PATH@ in run.sh has to be changed to a valid path which is used to share thins like a precompiled batman-adv.ko and other tools + +<pre><code class="shell"> cat > run.sh << "EOF" #! /bin/bash

@@ -81,11 +109,13 @@ done EOF

chmod +x run.sh -</pre> +</code></pre> + +h3. Automatic test initialization

-The test-init.sh script can be used to automatically initialize the test setup during boot: +The test-init.sh script in the SHARED_PATH can be used to automatically initialize the test setup during boot. A simple example is:

-<pre> +<pre><code class="shell"> cat > test-init.sh << "EOF" #! /bin/sh

@@ -96,21 +126,23 @@ set -e rmmod batman-adv || true modprobe batman-adv batctl routing_algo BATMAN_IV -batctl if add dummy0 -batctl it 5000 batctl if add eth0 +batctl it 5000 ip link set up dev eth0 ip link set up dev bat0 EOF

chmod +x test-init.sh -</pre> +</code></pre>

+h3. Start + Everything can then be started up inside a screen session

-<pre> +<pre><code class="shell"> screen -./hub.sh +./interconnect.sh ./run.sh -</pre> \ No newline at end of file +</code></pre> +