Introduce a service to wait for network uplink

Fixes: QubesOS/qubes-issues#10173
For: QubesOS/qubes-issues#1512

Author: ben-grande

debian/qubes-core-agent.install

@@ -39,6 +39,7 @@ etc/qubes-rpc/qubes.VMExecGUI
 etc/qubes-rpc/qubes.VMRootExec
 etc/qubes-rpc/qubes.WaitForSession
 etc/qubes-rpc/qubes.WaitForRunningSystem
+etc/qubes-rpc/qubes.WaitForNetworkUplink
 etc/qubes-rpc/qubes.GetDate
 etc/qubes-suspend-module-blacklist
 etc/qubes/autostart/*

qubes-rpc/Makefile

@@ -79,6 +79,7 @@ install:
 		qubes.SuspendPostAll \
 		qubes.WaitForSession \
 		qubes.WaitForRunningSystem \
+		qubes.WaitForNetworkUplink \
 		qubes.DetachPciDevice \
 		qubes.Backup qubes.Restore \
 		qubes.RegisterBackupLocation \

qubes-rpc/qubes.WaitForNetworkUplink

@@ -0,0 +1,31 @@
+#!/bin/bash
+# Wait with a timeout for the uplink service to be started. Used on deferred netvm.
+set -eu
+
+# shellcheck disable=SC1091
+. /usr/lib/qubes/init/functions
+iface="$(get_qubes_managed_iface)"
+if test -z "$iface"; then
+  exit
+fi
+
+i=0
+while test $i -le 10; do
+  if systemctl is-active --quiet "qubes-network-uplink@$iface.service"; then
+    have_qubesdb || exit 0
+    gateway="$(qubesdb-read /qubes-gateway)" || true
+    gateway6="$(qubesdb-read /qubes-gateway6)" || true
+    # Even if there is packet loss, skip failure as the command returning
+    # means it connected to the uplink.
+    if test -n "$gateway"; then
+      ping -c1 -n "$gateway" || true
+    fi
+    if test -n "$gateway6"; then
+      ping -c1 -n -6 "$gateway6" || true
+    fi
+    exit 0
+  fi
+  sleep 0.3
+  i=$((i+1))
+done
+exit 3

rpm_spec/core-agent.spec.in

@@ -903,6 +903,7 @@ rm -f %{name}-%{version}
 %config(noreplace) /etc/qubes-rpc/qubes.SuspendPostAll
 %config(noreplace) /etc/qubes-rpc/qubes.WaitForSession
 %config(noreplace) /etc/qubes-rpc/qubes.WaitForRunningSystem
+%config(noreplace) /etc/qubes-rpc/qubes.WaitForNetworkUplink
 %config(noreplace) /etc/qubes-rpc/qubes.DetachPciDevice
 %config(noreplace) /etc/qubes-rpc/qubes.Backup
 %config(noreplace) /etc/qubes-rpc/qubes.Restore