Crate smolvm_network 

Host-side virtio-net runtime.

Context

This module is the host-side half of the new networking path:

guest app
  -> guest kernel TCP/IP stack
  -> virtio-net device
  -> libkrun unix-stream bridge
  -> smolvm FrameStreamBridge
  -> shared frame queues
  -> smoltcp gateway/runtime
  -> host sockets / DNS forwarding / TCP relay
  -> external network

Main runtime components:

VirtioNetworkRuntime
├─ FrameStreamBridge
│  ├─ reader thread
│  └─ writer thread
├─ TcpPortListeners
│  └─ one non-blocking accept loop per `-p HOST:GUEST`
├─ Arc<NetworkFrameQueues>
│  ├─ guest_to_host
│  ├─ host_to_guest
│  ├─ guest_wake
│  ├─ host_wake
│  └─ relay_wake
└─ smolvm-net-poll thread
   ├─ VirtioNetworkDevice
   ├─ smoltcp Interface
   ├─ SocketSet
   └─ TcpRelayTable

Component roles:

• FrameStreamBridge: translates libkrun’s Unix-stream frame protocol into queue operations
• TcpPortListeners: accepts host TCP connections for published ports and hands them to the poll loop
• NetworkFrameQueues: handoff boundary between threads
• VirtioNetworkDevice: adapts those queues to smoltcp’s phy::Device
• poll thread: acts as the guest-visible gateway and protocol dispatcher
• TcpRelayTable: maps guest TCP flows onto host-side relay threads

This runtime is responsible for:

• exchanging raw Ethernet frames with libkrun
• presenting a gateway endpoint to the guest
• handling DNS through a gateway UDP socket and host UDP forwarding
• relaying guest TCP connections to host TcpStreams
• accepting published host TCP ports and forwarding them into guest TCP connections

Modules

device

smoltcp phy::Device adapter for the virtio-net backend.

frame_stream

libkrun unix-stream framing for the virtio-net backend.

queues

Shared queues and wake notifications for the virtio-net backend.

stack

Host-side smoltcp runtime for the virtio-net backend.

tcp_listeners

Host-side TCP listeners for published virtio-net ports.

tcp_relay

TCP relay support for the virtio-net backend.

Structs

GuestNetworkConfig

Static guest network configuration for the virtio-net MVP.

PortMapping

Host->guest published TCP port mapping serviced by the virtio gateway.

VirtioNetworkRuntime

Running host-side virtio-net runtime for one guest NIC.

Constants

DEFAULT_DNS_ADDR

Default upstream DNS resolver used by the gateway runtime.

Functions

start_virtio_network

Start the host-side virtio-net runtime for one guest NIC.