Netstack contains TCP/IP network stack and talks to network drivers. It serves as a back-end for mxio socket API.

Netstack is automatically started by netsvc during system start-up. You don't have to run it manually. In this mode, netstack handles IPv4 packets only.

If you want netstack to handle IPv6 packets as well, you have to disable netsvc. See Start netstack manually for more details.

Netstack acquires an IPv4 address using DHCP.

$ ./scripts/build-sysroot.sh
$ ./packages/gn/gen.py --modules netstack
$ ./buildtools/ninja -C out/debug-x86-64

Create a tap interface called qemu if you haven't done so. This magenta document has instructions.

Choose an IPv4 subnet to use, for example, 192.168.3.0/24. Assign 192.168.3.1 to the tap interface.

$ sudo ifconfig qemu 192.168.3.1/24

You need a DHCPv4 server running for the subnet. In this document, we use dnsmasq. It also forwards DNS queries to upstream.

On Ubuntu, install dnsmasq with apt-get.

$ sudo apt-get install dnsmasq

On Mac, you can use homebrew to install dnsmasq.

$ brew install dnsmasq

You need these 2 lines in your dnsmasq.conf. You can delete everything else.

On Ubuntu, edit /etc/dnsmasq.conf.

interface=qemu
dhcp-range=qemu,192.168.3.50,192.168.3.150,24h

On Mac, edit /usr/local/etc/dnsmasq.conf (or $HOMEBREW_PREFIX/etc/dnsmasq.conf if you changed the installation dir).

interface=tap0
dhcp-range=tap0,192.168.3.50,192.168.3.150,24h

Restart dnsmasq.

On Ubuntu,

$ sudo /etc/init.d/dnsmasq restart

On Mac (if you used homebrew),

$ sudo brew services restart dnsmasq

The dnsmasq service silently fails to start if the directory /var/log/misc does not exist. Just create it to fix.

Optionally you can set up NAT to route the traffic to an external network interface.

On Linux:

These instructions use eth0 as the name of that interface, but it may vary (to eth1, or something more exotic) on your particular machine.

Execute the following commands as root (you need this every time you reboot the machine).

echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i eth0 -o qemu -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i qemu -o eth0 -j ACCEPT

On Mac:

To set up NAT, run these commands every time qemu is started (because only then the tap0 interface is created):

sudo ifconfig tap0 192.168.3.1 up
sudo sysctl net.inet.ip.forwarding=1
echo "
nat on en0 from tap0:network to any -> (en0)
pass out on en0 inet from tap0:network to any
" | sudo pfctl -ef -

To confirm the NAT setup:

sudo pfctl -s nat

To clear the NAT and revert to the original pf.conf:

sudo pfctl -F all -f /etc/pf.conf

-N option will enable qemu's network feature

$ scripts/run-magenta-x86-64 -N -x out/debug-x86-64/user.bootfs

On the console, the IP address acquired from DHCP will be reported

[00004.917] U netstack: ip4_addr: 192.168.3.53

If you are connecting the Ethernet cable from NUC or Acer to a USB Ethernet adapter on Linux Desktop, you can use a set-up similar to the qemu case (if you connect your hardware directly to your Ethernet network, this step is not neccesary)

Choose an IPv4 subnet to use, for example, 192.168.2.0/24. Assign 192.168.2.1 to the USB Ethernet adapter (e.g. eth5)

$ sudo ifconfig eth5 192.168.2.1/24

Add these 2 lines to dnsmasq.conf.

interface=eth5
dhcp-range=eth5,192.168.2.50,192.168.2.150,24h

On Ubuntu, make sure that NetworkManager doesn't manage this interface. You can modify /etc/NetworkManager/NetworkManager.conf to ignore the device by specifying its MAC address (e.g. 12:34:56:78:9a:bc).

...
[ifupdown]
managed=false

[keyfile]
unmanaged-devices=mac:12:34:56:78:9a:bc

Once NetworkManager stops managing your interface, you will need to bring up the interface manually. Also you need to re-assign the IPv6 link-local address to the inteface if you want to use loglistner (if you don't remember its ipv6 link-local address, you can calculate it here from the MAC address of the USB Ethernet adapter).

$ sudo ifconfig eth5 up
$ sudo ip address add dev eth5 scope link ${ipv6_link_local_address}

If you disable netsvc, netstack won't run automatically. Use '-c netsvc.disable=true' option when you run the startup script.

$ scripts/run-magenta-x86-64 -N -x out/debug-x86-64/user.bootfs -c netsvc.disable=true

You can run netstack at the shell prompt.

> netstack&