[qemu] Formalize netdev backends
Introduce the Tap backend as well.
Change-Id: I71e1270ab5a392ff83403fc8c650833b5fe1d663
diff --git a/qemu/config.go b/qemu/config.go
index 495e770..42047f8 100644
--- a/qemu/config.go
+++ b/qemu/config.go
@@ -46,6 +46,18 @@
// ID is the network device identifier.
ID string
+ // User is a netdev user backend.
+ User *NetdevUser
+
+ // Tap is a netdev tap backend.
+ Tap *NetdevTap
+
+ // MAC is the network device MAC address.
+ MAC string
+}
+
+// NetdevUser defines a netdev backend giving user networking.
+type NetdevUser struct {
// Network is the network block.
Network string
@@ -60,9 +72,12 @@
// Forwards are the host forwardings.
Forwards []Forward
+}
- // MAC is the network device MAC address.
- MAC string
+// NetdevTap defines a netdev backend giving a tap interface.
+type NetdevTap struct {
+ // Name is the name of the interface.
+ Name string
}
// Config gives a high-level configuration for QEMU on Fuchsia.
@@ -162,22 +177,37 @@
}
for _, n := range cfg.Networks {
+ if n.ID == "" {
+ return nil, fmt.Errorf("a network must have an ID")
+ }
+
var netdev strings.Builder
- fmt.Fprintf(&netdev, "user,id=%s", n.ID)
- if n.Network != "" {
- fmt.Fprintf(&netdev, ",net=%s", n.Network)
- }
- if n.DHCPStart != "" {
- fmt.Fprintf(&netdev, ",dhcpstart=%s", n.DHCPStart)
- }
- if n.DNS != "" {
- fmt.Fprintf(&netdev, ",dns=%s", n.DNS)
- }
- if n.Host != "" {
- fmt.Fprintf(&netdev, ",host=%s", n.Host)
- }
- for _, f := range n.Forwards {
- fmt.Fprintf(&netdev, ",hostfwd=tcp::%d-:%d", f.HostPort, f.GuestPort)
+ if n.Tap != nil {
+ if n.Tap.Name == "" {
+ return nil, fmt.Errorf("network %q must specify a TAP interface name", n.ID)
+ }
+ // Overwrite any default configuration scripts with none; there is not currently a
+ // good use case for these parameters.
+ fmt.Fprintf(&netdev, "tap,id=%s,ifname=%s,script=no,downscript=no", n.ID, n.Tap.Name)
+ } else if n.User != nil {
+ fmt.Fprintf(&netdev, "user,id=%s", n.ID)
+ if n.User.Network != "" {
+ fmt.Fprintf(&netdev, ",net=%s", n.User.Network)
+ }
+ if n.User.DHCPStart != "" {
+ fmt.Fprintf(&netdev, ",dhcpstart=%s", n.User.DHCPStart)
+ }
+ if n.User.DNS != "" {
+ fmt.Fprintf(&netdev, ",dns=%s", n.User.DNS)
+ }
+ if n.User.Host != "" {
+ fmt.Fprintf(&netdev, ",host=%s", n.User.Host)
+ }
+ for _, f := range n.User.Forwards {
+ fmt.Fprintf(&netdev, ",hostfwd=tcp::%d-:%d", f.HostPort, f.GuestPort)
+ }
+ } else {
+ return nil, fmt.Errorf("network %q must specify a netdev backend", n.ID)
}
invocation = append(invocation, "-netdev", netdev.String())
@@ -188,6 +218,10 @@
}
invocation = append(invocation, "-device", device.String())
}
+ // Treat the absense of specified networks as a directive to disable networking entirely.
+ if len(cfg.Networks) == 0 {
+ invocation = append(invocation, "-net", "none")
+ }
invocation = append(invocation, "-append", strings.Join(cmdlineArgs, " "))
return invocation, nil
