[OE-core] [meta-oe][PATCH 0/3] runqemu improve networking
Adrian Freihofer
adrian.freihofer at gmail.com
Wed Nov 18 11:36:34 UTC 2015
Hi Aws
Creating tap devices, routes or changing the iptables requires extended permissions. runqemu-gen-tapdevs does the part
of the setup which requires to be done with extended permissions. runqemu does the part which is allowed to be done by a
regular user. Normally the tap devices can be "recycled" for many runs of runqemu. This allows to call runqemu-gen
-tapdevs once at boot as the only command running with sudo on the host.
runqemu-gen-tapdevs changes the iptables of the host. It configures a NAT rule to get the virtual device connected to
the Internet. For most use cases this is fine. But the NAT route prevents use cases where for example a bridged setup is
required. Therefore my patchset adds an optional parameter netmode, which makes runqemu-gen-tapdevs skipping the NAT
setup. If I remember correctly, runqemu-gen-tapdevs creates the NAT route for each tap interface. This is probabely not
what you want if you are going to connect more than one tap interface to one qemu instance. If you call runqemu-gen
-tapdevs with netmode set to hostonly, the virtual devices will not have a route to the internet. If a route from a
virtual device to the Internet is still required you need to setup the NAT route on one of the tap interfaces (e.g.
write a wrapper script around runqemu-gen-tapdevs). Instead of setting up the route on a tap interface it might be
better to add the tap interface to a bridge and to setup the route on the bridge.
Basic idea of a wrapper script (sudo):
# Setup a bridge with route to the Internet and dhcp/DNS server or what ever needed
ip link add ${bridge_name} type bridge
ip link set ${bridge_name} up
# Create the tap for the hostonly connection (IP 192.168.7.2)
runqemu-gen-tapdevs ${MYUID} ${MYGID} 1 ${sysroot_dir} hostonly
# Create second tap interface connected to the bridge
ip tuntap add ${tap_name} mode tap
ip link set ${tap_name} up
ip link set ${tap_name} master ${bridge_name}
# Finally qemu can be started (without sudo)
runqemu hostonly qemuparams="-device virtio-net-pci,netdev=netif1,mac=${macaddr1} -netdev
tap,id=netif1,ifname=${tap_name},script=no,downscript=no"
Regards,
Adrian
On Tue, 2015-11-17 at 21:22 -0500, Aws Ismail wrote:
> Adrian,
>
> I just have to add one last note here. I had to use
> runqemu-gen-tapdevs before runqemu to create the multiple tap devices
> (3 in total, tap0 is the default one you've mentioned, and then tap1
> and tap2). For example, I did this:
>
> sudo runqemu-gen-tapdevs <my uid> <my guid> 3 <path to my build's
> native sysroot>
>
> My thinking was that runqemu would do that for me since I am asking
> for two new extra netdev's but apparently not.
>
> On Tue, Nov 17, 2015 at 2:40 PM, Aws Ismail <aws.ismail at gmail.com> wrote:
> > Thanks Adrian for the explanation. I have tested it now and it works
> > fine in my case. I think this should be merged upstream because it is
> > an important feature to have specially if the user is planning to use
> > the VM for extended use.
> >
> >
> > Tested-by: Aws Ismail <aws.ismail at gmail.com>
> >
> >
> >
> > On Tue, Nov 17, 2015 at 7:24 AM, Adrian Freihofer
> > <adrian.freihofer at gmail.com> wrote:
> > > Hi Aws
> > >
> > > The interfaces of my virtual device are configured as:
> > > eth0: static IP, 192.168.7.2 (This IP is hard coded in many scripts of poky.)
> > > This interface is for debugging purpose, it is not available
> > > on my physical devices running in a productive environment.
> > > The interface is configured by the kernel command line
> > > provided by the runqemu script. This interface should
> > > (or must in case of NFS rootfs) be ignored by connman, networkmanager
> > > or what ever manages the network settings of your device.
> > > eth1: Configured by connman or networkmanager running on the virtual device.
> > > The part of the setup depends on the particular use case you need
> > > to emulate. In my setup the tap interfaces of the host ar part
> > > of a bridge. On the bridge a dnsmasq instance serves IP addresses.
> > > This part of my setup is not published. It is verry specific. But based
> > > on my patch set it should be easy to do something similar fitting your
> > > use case. The simplest approach might be a static IP address e.g.
> > > assigned by a bbappend file e.g. for connman.
> > >
> > > runqemu is started with additional parameters to create eth1:
> > > runqemu hostonly qemuparams="-device virtio-net-pci,netdev=netif1,mac=${macaddr1} -netdev
> > > tap,id=netif1,ifname=${HOST_TAP_NAME},script=no,downscript=no"
> > >
> > > Regards,
> > > Adrian
> > >
> > > On Mon, 2015-11-16 at 17:16 -0500, Aws Ismail wrote:
> > > > Hi Adrian,
> > > >
> > > > What's the runqemu line you are running with ?
> > > >
> > > > I am passing -net nic -net nic to the qemuparams line which works
> > > > fine, but the the two devices come up with no IP addresses.
> > > >
> > > > My full qemu line is:
> > > >
> > > > ROOTFS=<path to qemu.ext4> runqemu qemux86-64 nographic
> > > > qemuparams="-cpu host --enable-kvm -m 4096 -net nic -net nic"
> > > >
> > > > Aws\
> > > >
> > > > On Sun, Nov 15, 2015 at 1:01 AM, Aws Ismail <aws.ismail at gmail.com> wrote:
> > > > > Thanks Adrian for the patchset. I will test it and get back to you.
> > > > >
> > > > > Aws\
> > > > >
> > > > > On Sat, Nov 14, 2015 at 4:35 PM, Adrian Freihofer
> > > > > <adrian.freihofer at gmail.com> wrote:
> > > > > > This patch series adds two features to runqemu:
> > > > > > - Support the emulation of more than one NIC
> > > > > > - Add a hostonly networking mode. This networking mode enables
> > > > > > the user to implement different virtual networking environments
> > > > > > such as a bridged network as discussed in #7887.
> > > > > >
> > > > > > Note: Without the first patch connman fails if the virtual device
> > > > > > provides more than one NIC.
> > > > > >
> > > > > > @Aws Ismail: I'm using this since more than one year. Would be great
> > > > > > if you could test this and provide feedback.
> > > > > >
> > > > > > Adrian Freihofer (3):
> > > > > > connman: fix qemu config
> > > > > > runqemu: add support for multiple NICs
> > > > > > runqemu: support hostonly net mode
> > > > > >
> > > > > > .../connman/connman-conf/qemuall/wired-setup | 6 ++--
> > > > > > scripts/runqemu | 7 +++-
> > > > > > scripts/runqemu-gen-tapdevs | 11 ++++---
> > > > > > scripts/runqemu-ifdown | 33 +++++++++++--------
> > > > > > scripts/runqemu-ifup | 38 +++++++++++++---------
> > > > > > scripts/runqemu-internal | 21 +++++++-----
> > > > > > 6 files changed, 72 insertions(+), 44 deletions(-)
> > > > > >
> > > > > > --
> > > > > > 2.4.3
> > > > > >
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