This implements XML config to represent a subset of the features
supported by 'passt' (https://passt.top), which is an alternative
backend for emulated network devices that requires no elevated
privileges (similar to slirp, but "better").
Along with setting the backend to use passt (via <backend
type='passt'/> when the interface type='user'), we also support
passt's --log-file and --interface options (via the <backend>
subelement logFile and upstream attributes) and its --tcp-ports and
--udp-ports options (which selectively forward incoming connections to
the host on to the guest) via the new <portForward> subelement of
<interface>. Here is an example of the config for a network interface
that uses passt to connect:
<interface type='user'>
<mac address='52:54:00:a8:33:fc'/>
<ip address='192.168.221.122' family='ipv4'/>
<model type='virtio'/>
<backend type='passt' logFile='/tmp/xyzzy.log' upstream='eth0'/>
<portForward address='10.0.0.1' proto='tcp' dev='eth0'>
<range start='2022' to='22'/>
<range start='5000' end='5099' to='1000'/>
<range start='5010' end='5029' exclude='yes'/>
</portForward>
<portForward proto='udp'>
<range start='10101'/>
</portForward>
</interface>
In this case:
* the guest will be offered address 192.168.221.122 for its interface
via DHCP
* the passt process will write all log messages to /tmp/xyzzy.log
* routes to the outside for the guest will be derived from the
addresses and routes associated with the host interface "eth0".
* incoming tcp port 2022 to the host will be forwarded to port 22
on the guest.
* incoming tcp ports 5000-5099 (with the exception of ports 5010-5029)
to the host will be forwarded to port 1000-1099 on the guest.
* incoming udp packets on port 10101 will be forwarded (unchanged) to
the guest.
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
