feat: Improve network error handling (#856)

  fi

  # Create a macvtap network for the VM guest

  { ip link add link "$VM_NET_DEV" name "$VM_NET_TAP" address "$VM_NET_MAC" type macvtap mode bridge ; rc=$?; } || :

  { msg=$(ip link add link "$VM_NET_DEV" name "$VM_NET_TAP" address "$VM_NET_MAC" type macvtap mode bridge 2>&1); rc=$?; } || :

  case "$msg" in

    "RTNETLINK answers: File exists"* )

      while ! ip link add link "$VM_NET_DEV" name "$VM_NET_TAP" address "$VM_NET_MAC" type macvtap mode bridge; do

        info "Waiting for macvtap interface to become available.."

        sleep 5

      done  ;;

    "RTNETLINK answers: Invalid argument"* )

      error "Cannot create macvtap interface. Please make sure that the network type of the container is 'macvlan' and not 'ipvlan'."

      return 1 ;;

    "RTNETLINK answers: Operation not permitted"* )

      error "No permission to create macvtap interface. Please make sure that your host kernel supports it and that the NET_ADMIN capability is set." 

      return 1 ;;

    *)

      [ -n "$msg" ] && echo "$msg" >&2

      if (( rc != 0 )); then

    error "Cannot create macvtap interface. Please make sure that the network type is 'macvlan' and not 'ipvlan',"

    error "that your kernel is recent (>4) and supports it, and that the container has the NET_ADMIN capability set." && return 1

  fi

        error "Cannot create macvtap interface."

        return 1

      fi ;;

  esac

  while ! ip link set "$VM_NET_TAP" up; do

    info "Waiting for MAC address $VM_NET_MAC to become available..."

  local name

  local os=""

  local if="macvlan"

  name=$(uname -a)

  [[ "${name,,}" == *"darwin"* ]] && os="MacOS"

  [[ "${name,,}" == *"microsoft"* ]] && os="Windows"

  [[ "${name,,}" == *"darwin"* ]] && os="Docker Desktop for macOS"

  [[ "${name,,}" == *"microsoft"* ]] && os="Docker Desktop for Windows"

  if [[ "$DHCP" == [Yy1]* ]]; then

    if="macvtap"

    [[ "${name,,}" == *"synology"* ]] && os="Synology Container Manager"

  fi

  if [ -n "$os" ]; then

    warn "you are using Docker Desktop for $os which does not support macvlan, please revert to bridge networking!"

    warn "you are using $os which does not support $if, please revert to bridge networking!"

  fi

  return 0

    if ! configureNAT; then

      NETWORK="user"

      warn "falling back to usermode networking! Performance will be bad and port forwarding will not work."

      warn "falling back to usermode networking! Performance will be bad and port mapping will not work."

      ip link set "$VM_NET_TAP" down promisc off &> null || true

      ip link delete "$VM_NET_TAP" &> null || true