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daemon split (1/5): extract *HostNetwork service

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First phase of splitting the daemon god-struct into focused services
with explicit ownership.

HostNetwork now owns everything host-networking: the TAP interface
pool (initializeTapPool / ensureTapPool / acquireTap / releaseTap /
createTap), bridge + socket dir setup, firecracker process primitives
(find/resolve/kill/wait/ensureSocketAccess/sendCtrlAltDel), DM
snapshot lifecycle, NAT rule enforcement, guest DNS server lifecycle
+ routing setup, and the vsock-agent readiness probe. That's 7 files
whose receivers flipped from *Daemon to *HostNetwork, plus a new
host_network.go that declares the struct, its hostNetworkDeps, and
the factored firecracker + DNS helpers that used to live in vm.go.

Daemon gives up the tapPool and vmDNS fields entirely; they're now
HostNetwork's business. Construction goes through newHostNetwork in
Daemon.Open with an explicit dependency bag (runner, logger, config,
layout, closing). A lazy-init hostNet() helper on Daemon supports
test literals that don't wire net explicitly — production always
populates it eagerly.

Signature tightenings where the old receiver reached into VM-service
state:
 - ensureNAT(ctx, vm, enable) → ensureNAT(ctx, guestIP, tap, enable).
   Callers resolve tap from the handle cache themselves.
 - initializeTapPool(ctx) → initializeTapPool(usedTaps []string).
   Daemon.Open enumerates VMs, collects taps from handles, hands the
   slice in.

rebuildDNS stays on *Daemon as the orchestrator — it filters by
vm-alive (a VMService concern handles will move to in phase 4) then
calls HostNetwork.replaceDNS with the already-filtered map.

Capability hooks continue to take *Daemon; they now use it as a
facade to reach services (d.net.ensureNAT, d.hostNet().*). Planned
CapabilityHost interface extraction is orthogonal, left for later.

Tests: dns_routing_test.go + fastpath_test.go + nat_test.go +
snapshot_test.go + open_close_test.go were touched to construct
HostNetwork literals where they exercise its methods directly, or
route through d.hostNet() where they exercise the Daemon entry
points.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Thales Maciel 2026-04-20 20:11:46 -03:00
parent eba9a553bf
commit 362009d747
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GPG key ID: 33112E6833C34679
18 changed files with 461 additions and 326 deletions
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17
internal/daemon/preflight.go
View file

@ -25,23 +25,6 @@ func (d *Daemon) validateWorkDiskResizePrereqs() error {
return checks.Err("work disk resize preflight failed")
}
func (d *Daemon) addNATPrereqs(ctx context.Context, checks *system.Preflight) {
checks.RequireCommand("iptables", toolHint("iptables"))
checks.RequireCommand("sysctl", toolHint("sysctl"))
runner := d.runner
if runner == nil {
runner = system.NewRunner()
}
out, err := runner.Run(ctx, "ip", "route", "show", "default")
if err != nil {
checks.Addf("failed to inspect the default route for NAT: %v", err)
return
}
if _, err := parseDefaultUplink(string(out)); err != nil {
checks.Addf("failed to detect the uplink interface for NAT: %v", err)
}
}
func (d *Daemon) addBaseStartPrereqs(checks *system.Preflight, image model.Image) {
d.addBaseStartCommandPrereqs(checks)
checks.RequireExecutable(d.config.FirecrackerBin, "firecracker binary", `install firecracker or set "firecracker_bin"`)