Add type hints

benchmarks/linear-raw-throughput.py

@@ -140,7 +140,7 @@ def main():
             if not r:
                 break
             out += r
-        if srv.poll() != None or clt.poll() != None:
+        if srv.poll() is not None or clt.poll() is not None:
             break
 
     if srv.poll():

setup.py

@@ -15,6 +15,6 @@ setup(
         license     = 'GPLv2',
         platforms   = 'Linux',
         packages    = ['nemu'],
-        install_requires = ['unshare', 'six'],
+        install_requires = ['unshare', 'six', 'attrs'],
         package_dir = {'': 'src'}
         )

src/nemu/__init__.py

@@ -41,7 +41,7 @@ class _Config(object):
         except KeyError:
             pass  # User not found.
 
-    def _set_run_as(self, user):
+    def _set_run_as(self, user: str | int):
         """Setter for `run_as'."""
         if str(user).isdigit():
             uid = int(user)
@@ -61,7 +61,7 @@ class _Config(object):
         self._run_as = run_as
         return run_as
 
-    def _get_run_as(self):
+    def _get_run_as(self) -> str:
         """Setter for `run_as'."""
         return self._run_as
 

src/nemu/compat.py

@@ -8,23 +8,21 @@ def pipe() -> tuple[int, int]:
     os.set_inheritable(b, True)
     return a, b
 
+
 def socket(*args, **kwargs) -> pysocket.socket:
     s = pysocket.socket(*args, **kwargs)
     s.set_inheritable(True)
     return s
 
+
 def socketpair(*args, **kwargs) -> tuple[pysocket.socket, pysocket.socket]:
     a, b = pysocket.socketpair(*args, **kwargs)
     a.set_inheritable(True)
     b.set_inheritable(True)
     return a, b
 
+
 def fromfd(*args, **kwargs) -> pysocket.socket:
     s = pysocket.fromfd(*args, **kwargs)
     s.set_inheritable(True)
     return s
-
-def fdopen(*args, **kwargs) -> pysocket.socket:
-    s = os.fdopen(*args, **kwargs)
-    s.set_inheritable(True)
-    return s
\ No newline at end of file

src/nemu/environ.py

@@ -25,7 +25,7 @@ import subprocess
 import sys
 import syslog
 from syslog import LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG
-from typing import TypeVar, Callable
+from typing import TypeVar, Callable, Optional
 
 __all__ = ["IP_PATH", "TC_PATH", "BRCTL_PATH", "SYSCTL_PATH", "HZ"]
 
@@ -39,7 +39,7 @@ __all__ += ["set_log_level", "logger"]
 __all__ += ["error", "warning", "notice", "info", "debug"]
 
 
-def find_bin(name, extra_path=None):
+def find_bin(name: str, extra_path: Optional[list[str]] = None) -> Optional[str]:
     """Try hard to find the location of needed programs."""
     search = []
     if "PATH" in os.environ:
@@ -57,7 +57,7 @@ def find_bin(name, extra_path=None):
     return None
 
 
-def find_bin_or_die(name, extra_path=None):
+def find_bin_or_die(name: str, extra_path: Optional[list[str]] = None) -> str:
     """Try hard to find the location of needed programs; raise on failure."""
     res = find_bin(name, extra_path)
     if not res:
@@ -156,7 +156,7 @@ _log_syslog_opts = ()
 _log_pid = os.getpid()
 
 
-def set_log_level(level):
+def set_log_level(level: int):
     "Sets the log level for console messages, does not affect syslog logging."
     global _log_level
     assert level > LOG_ERR and level <= LOG_DEBUG
@@ -191,7 +191,7 @@ def _init_log():
     info("Syslog logging started")
 
 
-def logger(priority, message):
+def logger(priority: int, message: str):
     "Print a log message in syslog, console or both."
     if _log_use_syslog:
         if os.getpid() != _log_pid:

src/nemu/interface.py

@@ -19,30 +19,33 @@
 
 import os
 import weakref
+from typing import TypedDict
 
 import nemu.iproute
 from nemu.environ import *
 
 __all__ = ['NodeInterface', 'P2PInterface', 'ImportedInterface',
-'ImportedNodeInterface', 'Switch']
+           'ImportedNodeInterface', 'Switch']
+
 
 class Interface(object):
     """Just a base class for the *Interface classes: assign names and handle
     destruction."""
     _nextid = 0
+
     @staticmethod
-    def _gen_next_id():
+    def _gen_next_id() -> int:
         n = Interface._nextid
         Interface._nextid += 1
         return n
 
     @staticmethod
-    def _gen_if_name():
+    def _gen_if_name() -> str:
         n = Interface._gen_next_id()
         # Max 15 chars
         return "NETNSif-%.4x%.3x" % (os.getpid() & 0xffff, n)
 
-    def __init__(self, index):
+    def __init__(self, index: int):
         self._idx = index
         debug("%s(0x%x).__init__(), index = %d" % (self.__class__.__name__,
                                                    id(self), index))
@@ -55,7 +58,7 @@ class Interface(object):
         raise NotImplementedError
 
     @property
-    def index(self):
+    def index(self) -> int:
         """Interface index as seen by the kernel."""
         return self._idx
 
@@ -65,20 +68,35 @@ class Interface(object):
         control interfaces can be put into a Switch, for example."""
         return None
 
+
+class Ipv4Dict(TypedDict):
+    address: str
+    prefix_len: int
+    broadcast: str
+    family: str
+
+
+class Ipv6Dict(TypedDict):
+    address: str
+    prefix_len: int
+    family: str
+
+
 class NSInterface(Interface):
     """Add user-facing methods for interfaces that go into a netns."""
-    def __init__(self, node, index):
+
+    def __init__(self, node: "nemu.Node", index):
         super(NSInterface, self).__init__(index)
         self._slave = node._slave
         # Disable auto-configuration
         # you wish: need to take into account the nonetns mode; plus not
         # touching some pre-existing ifaces
-        #node.system([SYSCTL_PATH, '-w', 'net.ipv6.conf.%s.autoconf=0' %
-        #self.name])
+        # node.system([SYSCTL_PATH, '-w', 'net.ipv6.conf.%s.autoconf=0' %
+        # self.name])
         node._add_interface(self)
 
     # some black magic to automatically get/set interface attributes
-    def __getattr__(self, name):
+    def __getattr__(self, name: str):
         # If name starts with _, it must be a normal attr
         if name[0] == '_':
             return super(Interface, self).__getattribute__(name)
@@ -92,57 +110,59 @@ class NSInterface(Interface):
         iface = slave.get_if_data(self.index)
         return getattr(iface, name)
 
-    def __setattr__(self, name, value):
+    def __setattr__(self, name: str, value):
         if name[0] == '_':  # forbid anything that doesn't start with a _
             super(Interface, self).__setattr__(name, value)
             return
-        iface = nemu.iproute.interface(index = self.index)
+        iface = nemu.iproute.interface(index=self.index)
         setattr(iface, name, value)
         return self._slave.set_if(iface)
 
-    def add_v4_address(self, address, prefix_len, broadcast = None):
+    def add_v4_address(self, address: str, prefix_len: int, broadcast=None):
         addr = nemu.iproute.ipv4address(address, prefix_len, broadcast)
         self._slave.add_addr(self.index, addr)
 
-    def add_v6_address(self, address, prefix_len):
+    def add_v6_address(self, address: str, prefix_len: int):
         addr = nemu.iproute.ipv6address(address, prefix_len)
         self._slave.add_addr(self.index, addr)
 
-    def del_v4_address(self, address, prefix_len, broadcast = None):
+    def del_v4_address(self, address: str, prefix_len: int, broadcast=None):
         addr = nemu.iproute.ipv4address(address, prefix_len, broadcast)
         self._slave.del_addr(self.index, addr)
 
-    def del_v6_address(self, address, prefix_len):
+    def del_v6_address(self, address: str, prefix_len: int):
         addr = nemu.iproute.ipv6address(address, prefix_len)
         self._slave.del_addr(self.index, addr)
 
-    def get_addresses(self):
+    def get_addresses(self) -> list[Ipv4Dict | Ipv6Dict]:
         addresses = self._slave.get_addr_data(self.index)
         ret = []
         for a in addresses:
             if hasattr(a, 'broadcast'):
                 ret.append(dict(
-                    address = a.address,
-                    prefix_len = a.prefix_len,
-                    broadcast = a.broadcast,
-                    family = 'inet'))
+                    address=a.address,
+                    prefix_len=a.prefix_len,
+                    broadcast=a.broadcast,
+                    family='inet'))
             else:
                 ret.append(dict(
-                    address = a.address,
-                    prefix_len = a.prefix_len,
-                    family = 'inet6'))
+                    address=a.address,
+                    prefix_len=a.prefix_len,
+                    family='inet6'))
         return ret
 
+
 class NodeInterface(NSInterface):
     """Class to create and handle a virtual interface inside a name space, it
     can be connected to a Switch object with emulation of link
     characteristics."""
-    def __init__(self, node):
+
+    def __init__(self, node: "nemu.Node"):
         """Create a new interface. `node' is the name space in which this
         interface should be put."""
         self._slave = None
-        if1 = nemu.iproute.interface(name = self._gen_if_name())
-        if2 = nemu.iproute.interface(name = self._gen_if_name())
+        if1 = nemu.iproute.interface(name=self._gen_if_name())
+        if2 = nemu.iproute.interface(name=self._gen_if_name())
         ctl, ns = nemu.iproute.create_if_pair(if1, if2)
         try:
             nemu.iproute.change_netns(ns, node.pid)
@@ -165,18 +185,20 @@ class NodeInterface(NSInterface):
             self._slave.del_if(self.index)
         self._slave = None
 
+
 class P2PInterface(NSInterface):
     """Class to create and handle point-to-point interfaces between name
     spaces, without using Switch objects. Those do not allow any kind of
     traffic shaping.
     As two interfaces need to be created, instead of using the class
     constructor, use the P2PInterface.create_pair() static method."""
+
     @staticmethod
-    def create_pair(node1, node2):
+    def create_pair(node1: "nemu.Node", node2: "nemu.Node"):
         """Create and return a pair of connected P2PInterface objects,
         assigned to name spaces represented by `node1' and `node2'."""
-        if1 = nemu.iproute.interface(name = P2PInterface._gen_if_name())
-        if2 = nemu.iproute.interface(name = P2PInterface._gen_if_name())
+        if1 = nemu.iproute.interface(name=P2PInterface._gen_if_name())
+        if2 = nemu.iproute.interface(name=P2PInterface._gen_if_name())
         pair = nemu.iproute.create_if_pair(if1, if2)
         try:
             nemu.iproute.change_netns(pair[0], node1.pid)
@@ -206,6 +228,7 @@ class P2PInterface(NSInterface):
             self._slave.del_if(self.index)
         self._slave = None
 
+
 class ImportedNodeInterface(NSInterface):
     """Class to handle already existing interfaces inside a name space:
     real devices, tun devices, etc.
@@ -213,7 +236,8 @@ class ImportedNodeInterface(NSInterface):
     to be moved inside the name space.
     On destruction, the interface will be restored to the original name space
     and will try to restore the original state."""
-    def __init__(self, node, iface, migrate = True):
+
+    def __init__(self, node: "nemu.Node", iface, migrate=True):
         self._slave = None
         self._migrate = migrate
         if self._migrate:
@@ -244,17 +268,19 @@ class ImportedNodeInterface(NSInterface):
             nemu.iproute.set_if(self._original_state)
         self._slave = None
 
+
 class TapNodeInterface(NSInterface):
     """Class to create a tap interface inside a name space, it
     can be connected to a Switch object with emulation of link
     characteristics."""
-    def __init__(self, node, use_pi = False):
+
+    def __init__(self, node, use_pi=False):
         """Create a new tap interface. 'node' is the name space in which this
         interface should be put."""
         self._fd = None
         self._slave = None
-        iface = nemu.iproute.interface(name = self._gen_if_name())
-        iface, self._fd = nemu.iproute.create_tap(iface, use_pi = use_pi)
+        iface = nemu.iproute.interface(name=self._gen_if_name())
+        iface, self._fd = nemu.iproute.create_tap(iface, use_pi=use_pi)
         nemu.iproute.change_netns(iface.name, node.pid)
         super(TapNodeInterface, self).__init__(node, iface.index)
 
@@ -271,18 +297,20 @@ class TapNodeInterface(NSInterface):
         except:
             pass
 
+
 class TunNodeInterface(NSInterface):
     """Class to create a tun interface inside a name space, it
     can be connected to a Switch object with emulation of link
     characteristics."""
-    def __init__(self, node, use_pi = False):
+
+    def __init__(self, node, use_pi=False):
         """Create a new tap interface. 'node' is the name space in which this
         interface should be put."""
         self._fd = None
         self._slave = None
-        iface = nemu.iproute.interface(name = self._gen_if_name())
-        iface, self._fd = nemu.iproute.create_tap(iface, use_pi = use_pi,
-                tun = True)
+        iface = nemu.iproute.interface(name=self._gen_if_name())
+        iface, self._fd = nemu.iproute.create_tap(iface, use_pi=use_pi,
+                                                  tun=True)
         nemu.iproute.change_netns(iface.name, node.pid)
         super(TunNodeInterface, self).__init__(node, iface.index)
 
@@ -299,9 +327,11 @@ class TunNodeInterface(NSInterface):
         except:
             pass
 
+
 class ExternalInterface(Interface):
     """Add user-facing methods for interfaces that run in the main
     namespace."""
+
     @property
     def control(self):
         # This is *the* control interface
@@ -316,11 +346,11 @@ class ExternalInterface(Interface):
         if name[0] == '_':  # forbid anything that doesn't start with a _
             super(ExternalInterface, self).__setattr__(name, value)
             return
-        iface = nemu.iproute.interface(index = self.index)
+        iface = nemu.iproute.interface(index=self.index)
         setattr(iface, name, value)
         return nemu.iproute.set_if(iface)
 
-    def add_v4_address(self, address, prefix_len, broadcast = None):
+    def add_v4_address(self, address, prefix_len, broadcast=None):
         addr = nemu.iproute.ipv4address(address, prefix_len, broadcast)
         nemu.iproute.add_addr(self.index, addr)
 
@@ -328,7 +358,7 @@ class ExternalInterface(Interface):
         addr = nemu.iproute.ipv6address(address, prefix_len)
         nemu.iproute.add_addr(self.index, addr)
 
-    def del_v4_address(self, address, prefix_len, broadcast = None):
+    def del_v4_address(self, address, prefix_len, broadcast=None):
         addr = nemu.iproute.ipv4address(address, prefix_len, broadcast)
         nemu.iproute.del_addr(self.index, addr)
 
@@ -342,23 +372,26 @@ class ExternalInterface(Interface):
         for a in addresses:
             if hasattr(a, 'broadcast'):
                 ret.append(dict(
-                    address = a.address,
-                    prefix_len = a.prefix_len,
-                    broadcast = a.broadcast,
-                    family = 'inet'))
+                    address=a.address,
+                    prefix_len=a.prefix_len,
+                    broadcast=a.broadcast,
+                    family='inet'))
             else:
                 ret.append(dict(
-                    address = a.address,
-                    prefix_len = a.prefix_len,
-                    family = 'inet6'))
+                    address=a.address,
+                    prefix_len=a.prefix_len,
+                    family='inet6'))
         return ret
 
+
 class SlaveInterface(ExternalInterface):
     """Class to handle the main-name-space-facing half of NodeInterface.
     Does nothing, just avoids any destroy code."""
+
     def destroy(self):
         pass
 
+
 class ImportedInterface(ExternalInterface):
     """Class to handle already existing interfaces. Analogous to
     ImportedNodeInterface, this class only differs in that the interface is
@@ -366,6 +399,7 @@ class ImportedInterface(ExternalInterface):
     connected to Switch objects and not assigned to a name space.  On
     destruction, the code will try to restore the interface to the state it
     was in before being imported into nemu."""
+
     def __init__(self, iface):
         self._original_state = None
         iface = nemu.iproute.get_if(iface)
@@ -379,6 +413,7 @@ class ImportedInterface(ExternalInterface):
             nemu.iproute.set_if(self._original_state)
         self._original_state = None
 
+
 # Switch is just another interface type
 
 class Switch(ExternalInterface):
@@ -421,7 +456,7 @@ class Switch(ExternalInterface):
                 if self._check_port(i.index):
                     setattr(i, name, value)
         # Set bridge
-        iface = nemu.iproute.bridge(index = self.index)
+        iface = nemu.iproute.bridge(index=self.index)
         setattr(iface, name, value)
         nemu.iproute.set_bridge(iface)
 
@@ -472,12 +507,12 @@ class Switch(ExternalInterface):
         self._apply_parameters({}, iface.control)
         del self._ports[iface.control.index]
 
-    def set_parameters(self, bandwidth = None,
-            delay = None, delay_jitter = None,
-            delay_correlation = None, delay_distribution = None,
-            loss = None, loss_correlation = None,
-            dup = None, dup_correlation = None,
-            corrupt = None, corrupt_correlation = None):
+    def set_parameters(self, bandwidth=None,
+                       delay=None, delay_jitter=None,
+                       delay_correlation=None, delay_distribution=None,
+                       loss=None, loss_correlation=None,
+                       dup=None, dup_correlation=None,
+                       corrupt=None, corrupt_correlation=None):
         """Set the parameters that control the link characteristics. For the
         description of each, refer to netem documentation:
         http://www.linuxfoundation.org/collaborate/workgroups/networking/netem
@@ -492,13 +527,13 @@ class Switch(ExternalInterface):
           `dup_correlation', `corrupt', and `corrupt_correlation' take a
           percentage value in the form of a number between 0 and 1. (50% is
           passed as 0.5)."""
-        parameters = dict(bandwidth = bandwidth,
-                delay = delay, delay_jitter = delay_jitter,
-                delay_correlation = delay_correlation,
-                delay_distribution = delay_distribution,
-                loss = loss, loss_correlation = loss_correlation,
-                dup = dup, dup_correlation = dup_correlation,
-                corrupt = corrupt, corrupt_correlation = corrupt_correlation)
+        parameters = dict(bandwidth=bandwidth,
+                          delay=delay, delay_jitter=delay_jitter,
+                          delay_correlation=delay_correlation,
+                          delay_distribution=delay_distribution,
+                          loss=loss, loss_correlation=loss_correlation,
+                          dup=dup, dup_correlation=dup_correlation,
+                          corrupt=corrupt, corrupt_correlation=corrupt_correlation)
         try:
             self._apply_parameters(parameters)
         except:
@@ -506,7 +541,6 @@ class Switch(ExternalInterface):
             raise
         self._parameters = parameters
 
-    def _apply_parameters(self, parameters, port = None):
+    def _apply_parameters(self, parameters, port=None):
         for i in [port] if port else list(self._ports.values()):
             nemu.iproute.set_tc(i.index, **parameters)
-

src/nemu/iproute.py

@@ -24,7 +24,10 @@ import re
 import socket
 import struct
 import sys
+from typing import TypeVar, Callable, Literal
 
+from attr import evolve
+from attrs import define, setters, field
 import six
 
 from nemu.environ import *
@@ -46,18 +49,21 @@ def _any_to_bool(any):
         return any != ""
     return bool(any)
 
+
 def _positive(val):
     v = int(val)
     if v <= 0:
         raise ValueError("Invalid value: %d" % v)
     return v
 
+
 def _non_empty_str(val):
     if val == "":
         return None
     else:
         return str(val)
 
+
 def _fix_lladdr(addr):
     foo = addr.lower()
     if ":" in addr:
@@ -77,21 +83,41 @@ def _fix_lladdr(addr):
     # Glue
     return ":".join(m.groups())
 
-def _make_getter(attr, conv = lambda x: x):
+
+def _make_getter(attr, conv=lambda x: x):
     def getter(self):
         return conv(getattr(self, attr))
+
     return getter
 
-def _make_setter(attr, conv = lambda x: x):
+
+def _make_setter(attr, conv=lambda x: x):
     def setter(self, value):
-        if value == None:
+        if value is None:
             setattr(self, attr, None)
         else:
             setattr(self, attr, conv(value))
+
     return setter
 
+
+T = TypeVar("T")
+U = TypeVar("U")
+
+
+def _if_any(conv: Callable[[T], U]):
+    def c(val: T) -> U:
+        if val is None:
+            return None
+        else:
+            return conv(val)
+
+    return c
+
+
 # classes for internal use
-class interface(object):
+@define(repr=False)
+class interface:
     """Class for internal use. It is mostly a data container used to easily
     pass information around; with some convenience methods."""
 
@@ -99,25 +125,14 @@ class interface(object):
     changeable_attributes = ["name", "mtu", "lladdr", "broadcast", "up",
                              "multicast", "arp"]
 
-    # Index should be read-only
-    index = property(_make_getter("_index"))
-    up = property(_make_getter("_up"), _make_setter("_up", _any_to_bool))
-    mtu = property(_make_getter("_mtu"), _make_setter("_mtu", _positive))
-    lladdr = property(_make_getter("_lladdr"),
-            _make_setter("_lladdr", _fix_lladdr))
-    arp = property(_make_getter("_arp"), _make_setter("_arp", _any_to_bool))
-    multicast = property(_make_getter("_mc"), _make_setter("_mc", _any_to_bool))
-
-    def __init__(self, index = None, name = None, up = None, mtu = None,
-            lladdr = None, broadcast = None, multicast = None, arp = None):
-        self._index     = _positive(index) if index is not None else None
-        self.name       = name
-        self.up         = up
-        self.mtu        = mtu
-        self.lladdr     = lladdr
-        self.broadcast  = broadcast
-        self.multicast  = multicast
-        self.arp        = arp
+    index: int = field(default=None, converter=_if_any(_positive), on_setattr=setters.frozen)
+    name: str = field(default=None)
+    up: bool = field(default=None, converter=_if_any(_any_to_bool))
+    mtu: int = field(default=None, converter=_if_any(_positive))
+    lladdr: str = field(default=None, converter=_if_any(_fix_lladdr))
+    broadcast: str = field(default=None)
+    multicast: bool = field(default=None, converter=_if_any(_any_to_bool))
+    arp: bool = field(default=None, converter=_if_any(_any_to_bool))
 
     def __repr__(self):
         s = "%s.%s(index = %s, name = %s, up = %s, mtu = %s, lladdr = %s, "
@@ -139,26 +154,23 @@ class interface(object):
         broadcast = None if self.broadcast == o.broadcast else self.broadcast
         multicast = None if self.multicast == o.multicast else self.multicast
         arp = None if self.arp == o.arp else self.arp
-        return self.__class__(self.index, name, up, mtu, lladdr, broadcast,
+        return interface(self.index, name, up, mtu, lladdr, broadcast,
                          multicast, arp)
 
     def copy(self):
         return copy.copy(self)
 
+
+@define(repr=False)
 class bridge(interface):
     changeable_attributes = interface.changeable_attributes + ["stp",
                                                                "forward_delay", "hello_time", "ageing_time", "max_age"]
 
-    # Index should be read-only
-    stp = property(_make_getter("_stp"), _make_setter("_stp", _any_to_bool))
-    forward_delay = property(_make_getter("_forward_delay"),
-            _make_setter("_forward_delay", float))
-    hello_time = property(_make_getter("_hello_time"),
-            _make_setter("_hello_time", float))
-    ageing_time = property(_make_getter("_ageing_time"),
-            _make_setter("_ageing_time", float))
-    max_age = property(_make_getter("_max_age"),
-            _make_setter("_max_age", float))
+    stp: bool = field(default=None, converter=_if_any(_any_to_bool))
+    forward_delay: float = field(default=None, converter=_if_any(float))
+    hello_time: float = field(default=None, converter=_if_any(float))
+    ageing_time: float = field(default=None, converter=_if_any(float))
+    max_age: float = field(default=None, converter=_if_any(float))
 
     @classmethod
     def upgrade(cls, iface, *kargs, **kwargs):
@@ -166,18 +178,6 @@ class bridge(interface):
         return cls(iface.index, iface.name, iface.up, iface.mtu, iface.lladdr,
                    iface.broadcast, iface.multicast, iface.arp, *kargs, **kwargs)
 
-    def __init__(self, index = None, name = None, up = None, mtu = None,
-            lladdr = None, broadcast = None, multicast = None, arp = None,
-            stp = None, forward_delay = None, hello_time = None,
-            ageing_time = None, max_age = None):
-        super(bridge, self).__init__(index, name, up, mtu, lladdr, broadcast,
-                multicast, arp)
-        self.stp            = stp
-        self.forward_delay  = forward_delay
-        self.hello_time     = hello_time
-        self.ageing_time    = ageing_time
-        self.max_age        = max_age
-
     def __repr__(self):
         s = "%s.%s(index = %s, name = %s, up = %s, mtu = %s, lladdr = %s, "
         s += "broadcast = %s, multicast = %s, arp = %s, stp = %s, "
@@ -193,7 +193,7 @@ class bridge(interface):
                     self.max_age.__repr__())
 
     def __sub__(self, o):
-        r = super(bridge, self).__sub__(o)
+        r = bridge.upgrade(super().__sub__(o))
         if type(o) == interface:
             return r
         r.stp = None if self.stp == o.stp else self.stp
@@ -206,11 +206,18 @@ class bridge(interface):
         r.max_age = None if self.max_age == o.max_age else self.max_age
         return r
 
+
 class address(object):
     """Class for internal use. It is mostly a data container used to easily
     pass information around; with some convenience methods. __eq__ and
     __hash__ are defined just to be able to easily find duplicated
     addresses."""
+
+    def __init__(self, address: str, prefix_len: int, family: socket.AddressFamily):
+        self.address = address
+        self.prefix_len = int(prefix_len)
+        self.family = family
+
     # broadcast is not taken into account for differentiating addresses
     def __eq__(self, o):
         if not isinstance(o, address):
@@ -223,12 +230,11 @@ class address(object):
              self.family.__hash__())
         return h
 
+
 class ipv4address(address):
-    def __init__(self, address, prefix_len, broadcast):
-        self.address = address
-        self.prefix_len = int(prefix_len)
+    def __init__(self, address: str, prefix_len: int, broadcast):
+        super().__init__(address, prefix_len, socket.AF_INET)
         self.broadcast = broadcast
-        self.family = socket.AF_INET
 
     def __repr__(self):
         s = "%s.%s(address = %s, prefix_len = %d, broadcast = %s)"
@@ -236,11 +242,10 @@ class ipv4address(address):
                     self.address.__repr__(), self.prefix_len,
                     self.broadcast.__repr__())
 
+
 class ipv6address(address):
-    def __init__(self, address, prefix_len):
-        self.address = address
-        self.prefix_len = int(prefix_len)
-        self.family = socket.AF_INET6
+    def __init__(self, address: str, prefix_len: int):
+        super().__init__(address, prefix_len, socket.AF_INET6)
 
     def __repr__(self):
         s = "%s.%s(address = %s, prefix_len = %d)"
@@ -264,8 +269,8 @@ class route(object):
     metric = property(_make_getter("_metric"),
                       lambda s, v: setattr(s, "_metric", int(v or 0)))
 
-    def __init__(self, tipe = "unicast", prefix = None, prefix_len = 0,
-            nexthop = None, interface = None, metric = 0):
+    def __init__(self, tipe="unicast", prefix=None, prefix_len=0,
+                 nexthop=None, interface=None, metric=0):
         self.tipe = tipe
         self.prefix = prefix
         self.prefix_len = prefix_len
@@ -289,20 +294,22 @@ class route(object):
                 self.prefix_len == o.prefix_len and self.nexthop == o.nexthop
                 and self.interface == o.interface and self.metric == o.metric)
 
+
 # helpers
-def _get_if_name(iface):
+def _get_if_name(iface: interface | int | str):
     if isinstance(iface, interface):
-        if iface.name != None:
+        if iface.name is not None:
             return iface.name
     if isinstance(iface, str):
         return iface
     return get_if(iface).name
 
+
 # XXX: ideally this should be replaced by netlink communication
 # Interface handling
 
 # FIXME: try to lower the amount of calls to retrieve data!!
-def get_if_data():
+def get_if_data() -> tuple[dict[int, interface], dict[str, interface]]:
     """Gets current interface information. Returns a tuple (byidx, bynam) in
     which each element is a dictionary with the same data, but using different
     keys: interface indexes and interface names.
@@ -323,21 +330,22 @@ def get_if_data():
                           r'brd ([0-9a-f:]+))?', line)
         flags = match.group(3).split(",")
         i = interface(
-                index   = match.group(1),
-                name    = match.group(2),
-                up      = "UP" in flags,
-                mtu     = match.group(4),
-                lladdr  = match.group(5),
-                arp     = not ("NOARP" in flags),
-                broadcast = match.group(6),
-                multicast = "MULTICAST" in flags)
+            index=match.group(1),
+            name=match.group(2),
+            up="UP" in flags,
+            mtu=match.group(4),
+            lladdr=match.group(5),
+            arp=not ("NOARP" in flags),
+            broadcast=match.group(6),
+            multicast="MULTICAST" in flags)
         byidx[idx] = bynam[i.name] = i
     return byidx, bynam
 
-def get_if(iface):
+
+def get_if(iface: interface | int | str) -> interface:
     ifdata = get_if_data()
     if isinstance(iface, interface):
-        if iface.index != None:
+        if iface.index is not None:
             return ifdata[0][iface.index]
         else:
             return ifdata[1][iface.name]
@@ -345,7 +353,8 @@ def get_if(iface):
         return ifdata[0][iface]
     return ifdata[1][iface]
 
-def create_if_pair(if1, if2):
+
+def create_if_pair(if1: interface, if2: interface) -> tuple[interface, interface]:
     assert if1.name and if2.name
 
     cmd = [[], []]
@@ -375,18 +384,20 @@ def create_if_pair(if1, if2):
     interfaces = get_if_data()[1]
     return interfaces[if1.name], interfaces[if2.name]
 
+
 def del_if(iface):
     ifname = _get_if_name(iface)
     execute([IP_PATH, "link", "del", ifname])
 
-def set_if(iface, recover = True):
-    def do_cmds(cmds, orig_iface):
+
+def set_if(iface: interface, recover=True):
+    def do_cmds(cmds: list[list[str]], orig_iface: interface):
         for c in cmds:
             try:
                 execute(c)
             except:
                 if recover:
-                    set_if(orig_iface, recover = False) # rollback
+                    set_if(orig_iface, recover=False)  # rollback
                     raise
 
     orig_iface = get_if(iface)
@@ -410,26 +421,28 @@ def set_if(iface, recover = True):
             # iface needs to be down
             cmds.append(_ils + ["down"])
         cmds.append(_ils + ["address", diff.lladdr])
-        if orig_iface.up and diff.up == None:
+        if orig_iface.up and diff.up is None:
             # restore if it was up and it's not going to be set later
             cmds.append(_ils + ["up"])
     if diff.mtu:
         cmds.append(_ils + ["mtu", str(diff.mtu)])
     if diff.broadcast:
         cmds.append(_ils + ["broadcast", diff.broadcast])
-    if diff.multicast != None:
+    if diff.multicast is not None:
         cmds.append(_ils + ["multicast", "on" if diff.multicast else "off"])
-    if diff.arp != None:
+    if diff.arp is not None:
         cmds.append(_ils + ["arp", "on" if diff.arp else "off"])
-    if diff.up != None:
+    if diff.up is not None:
         cmds.append(_ils + ["up" if diff.up else "down"])
 
     do_cmds(cmds, orig_iface)
 
+
 def change_netns(iface, netns):
     ifname = _get_if_name(iface)
     execute([IP_PATH, "link", "set", "dev", ifname, "netns", str(netns)])
 
+
 # Address handling
 
 def get_addr_data():
@@ -459,16 +472,16 @@ def get_addr_data():
         match = re.search(r'^\s*inet ([0-9.]+)/(\d+)(?: brd ([0-9.]+))?', line)
         if match:
             bynam[current].append(ipv4address(
-                address     = match.group(1),
-                prefix_len  = match.group(2),
-                broadcast   = match.group(3)))
+                address=match.group(1),
+                prefix_len=match.group(2),
+                broadcast=match.group(3)))
             continue
 
         match = re.search(r'^\s*inet6 ([0-9a-f:]+)/(\d+)', line)
         if match:
             bynam[current].append(ipv6address(
-                address     = match.group(1),
-                prefix_len  = match.group(2)))
+                address=match.group(1),
+                prefix_len=match.group(2)))
             continue
 
         # Extra info, ignored.
@@ -476,6 +489,7 @@ def get_addr_data():
 
     return byidx, bynam
 
+
 def add_addr(iface, address):
     ifname = _get_if_name(iface)
     addresses = get_addr_data()[1][ifname]
@@ -487,6 +501,7 @@ def add_addr(iface, address):
         cmd += ["broadcast", address.broadcast if address.broadcast else "+"]
     execute(cmd)
 
+
 def del_addr(iface, address):
     ifname = _get_if_name(iface)
     addresses = get_addr_data()[1][ifname]
@@ -496,6 +511,7 @@ def del_addr(iface, address):
            "%s/%d" % (address.address, int(address.prefix_len))]
     execute(cmd)
 
+
 # Bridge handling
 def _sysfs_read_br(brname):
     def readval(fname):
@@ -509,12 +525,13 @@ def _sysfs_read_br(brname):
     except:
         return None
     return dict(
-            stp             = readval(p + "stp_state"),
-            forward_delay   = float(readval(p + "forward_delay")) / 100,
-            hello_time      = float(readval(p + "hello_time")) / 100,
-            ageing_time     = float(readval(p + "ageing_time")) / 100,
-            max_age         = float(readval(p + "max_age")) / 100,
-            ports           = os.listdir(p2))
+        stp=readval(p + "stp_state"),
+        forward_delay=float(readval(p + "forward_delay")) / 100,
+        hello_time=float(readval(p + "hello_time")) / 100,
+        ageing_time=float(readval(p + "ageing_time")) / 100,
+        max_age=float(readval(p + "max_age")) / 100,
+        ports=os.listdir(p2))
+
 
 def get_bridge_data():
     # brctl stinks too much; it is better to directly use sysfs, it is
@@ -525,7 +542,7 @@ def get_bridge_data():
     ifdata = get_if_data()
     for iface in ifdata[0].values():
         brdata = _sysfs_read_br(iface.name)
-        if brdata == None:
+        if brdata is None:
             continue
         ports[iface.index] = [ifdata[1][x].index for x in brdata["ports"]]
         del brdata["ports"]
@@ -533,16 +550,18 @@ def get_bridge_data():
             bridge.upgrade(iface, **brdata)
     return byidx, bynam, ports
 
+
 def get_bridge(br):
     iface = get_if(br)
     brdata = _sysfs_read_br(iface.name)
-    #ports = [ifdata[1][x].index for x in brdata["ports"]]
+    # ports = [ifdata[1][x].index for x in brdata["ports"]]
     del brdata["ports"]
     return bridge.upgrade(iface, **brdata)
 
+
 def create_bridge(br):
     if isinstance(br, str):
-        br = interface(name = br)
+        br = interface(name=br)
     assert br.name
     execute([BRCTL_PATH, "addbr", br.name])
     try:
@@ -556,54 +575,60 @@ def create_bridge(br):
         six.reraise(t, v, bt)
     return get_if_data()[1][br.name]
 
+
 def del_bridge(br):
     brname = _get_if_name(br)
     execute([BRCTL_PATH, "delbr", brname])
 
-def set_bridge(br, recover = True):
+
+def set_bridge(br, recover=True):
     def saveval(fname, val):
         f = open(fname, "w")
         f.write(str(val))
         f.close()
+
     def do_cmds(basename, cmds, orig_br):
         for n, v in cmds:
             try:
                 saveval(basename + n, v)
             except:
                 if recover:
-                    set_bridge(orig_br, recover = False) # rollback
-                    set_if(orig_br, recover = False) # rollback
+                    set_bridge(orig_br, recover=False)  # rollback
+                    set_if(orig_br, recover=False)  # rollback
                     raise
 
     orig_br = get_bridge(br)
     diff = br - orig_br  # Only set what's needed
 
     cmds = []
-    if diff.stp != None:
+    if diff.stp is not None:
         cmds.append(("stp_state", int(diff.stp)))
-    if diff.forward_delay != None:
+    if diff.forward_delay is not None:
         cmds.append(("forward_delay", int(diff.forward_delay)))
-    if diff.hello_time != None:
+    if diff.hello_time is not None:
         cmds.append(("hello_time", int(diff.hello_time)))
-    if diff.ageing_time != None:
+    if diff.ageing_time is not None:
         cmds.append(("ageing_time", int(diff.ageing_time)))
-    if diff.max_age != None:
+    if diff.max_age is not None:
         cmds.append(("max_age", int(diff.max_age)))
 
     set_if(diff)
-    name = diff.name if diff.name != None else orig_br.name
+    name = diff.name if diff.name is not None else orig_br.name
     do_cmds("/sys/class/net/%s/bridge/" % name, cmds, orig_br)
 
+
 def add_bridge_port(br, iface):
     ifname = _get_if_name(iface)
     brname = _get_if_name(br)
     execute([BRCTL_PATH, "addif", brname, ifname])
 
+
 def del_bridge_port(br, iface):
     ifname = _get_if_name(iface)
     brname = _get_if_name(br)
     execute([BRCTL_PATH, "delif", brname, ifname])
 
+
 # Routing
 
 def get_all_route_data():
@@ -636,23 +661,27 @@ def get_all_route_data():
                          metric))
     return ret
 
-def get_route_data():
+
+def get_route_data() -> list[route]:
     # filter out non-unicast routes
     return [x for x in get_all_route_data() if x.tipe == "unicast"]
 
-def add_route(route):
+
+def add_route(route: route):
     # Cannot really test this
-    #if route in get_all_route_data():
+    # if route in get_all_route_data():
     #    raise ValueError("Route already exists")
     _add_del_route("add", route)
 
-def del_route(route):
+
+def del_route(route: route):
     # Cannot really test this
-    #if route not in get_all_route_data():
+    # if route not in get_all_route_data():
     #    raise ValueError("Route does not exist")
     _add_del_route("del", route)
 
-def _add_del_route(action, route):
+
+def _add_del_route(action: Literal["add", "del"], route: route):
     cmd = [IP_PATH, "route", action]
     if route.tipe != "unicast":
         cmd += [route.tipe]
@@ -666,6 +695,7 @@ def _add_del_route(action, route):
         cmd += ["dev", _get_if_name(route.interface)]
     execute(cmd)
 
+
 # TC stuff
 
 def get_tc_tree():
@@ -706,11 +736,15 @@ def get_tc_tree():
                 for h in data[data_node[0]]:
                     node["children"].append(gen_tree(data, h))
             return node
+
         tree[iface] = gen_tree(data[iface], data[iface][None][0])
     return tree
 
+
 _multipliers = {"M": 1000000, "K": 1000}
 _dividers = {"m": 1000, "u": 1000000}
+
+
 def _parse_netem_delay(line):
     ret = {}
     match = re.search(r'delay ([\d.]+)([mu]?)s(?: +([\d.]+)([mu]?)s)?' +
@@ -737,6 +771,7 @@ def _parse_netem_delay(line):
 
     return ret
 
+
 def _parse_netem_loss(line):
     ret = {}
     match = re.search(r'loss ([\d.]+)%(?: *([\d.]+)%)?', line)
@@ -748,6 +783,7 @@ def _parse_netem_loss(line):
         ret["loss_correlation"] = float(match.group(2)) / 100
     return ret
 
+
 def _parse_netem_dup(line):
     ret = {}
     match = re.search(r'duplicate ([\d.]+)%(?: *([\d.]+)%)?', line)
@@ -759,6 +795,7 @@ def _parse_netem_dup(line):
         ret["dup_correlation"] = float(match.group(2)) / 100
     return ret
 
+
 def _parse_netem_corrupt(line):
     ret = {}
     match = re.search(r'corrupt ([\d.]+)%(?: *([\d.]+)%)?', line)
@@ -770,6 +807,7 @@ def _parse_netem_corrupt(line):
         ret["corrupt_correlation"] = float(match.group(2)) / 100
     return ret
 
+
 def get_tc_data():
     tree = get_tc_tree()
     ifdata = get_if_data()
@@ -823,19 +861,21 @@ def get_tc_data():
             ret[i].update(_parse_netem_corrupt(netem[0]))
     return ret, ifdata[0], ifdata[1]
 
+
 def clear_tc(iface):
     iface = get_if(iface)
     tcdata = get_tc_data()[0]
-    if tcdata[iface.index] == None:
+    if tcdata[iface.index] is None:
         return
     # Any other case, we clean
     execute([TC_PATH, "qdisc", "del", "dev", iface.name, "root"])
 
-def set_tc(iface, bandwidth = None, delay = None, delay_jitter = None,
-        delay_correlation = None, delay_distribution = None,
-        loss = None, loss_correlation = None,
-        dup = None, dup_correlation = None,
-        corrupt = None, corrupt_correlation = None):
+
+def set_tc(iface, bandwidth=None, delay=None, delay_jitter=None,
+           delay_correlation=None, delay_distribution=None,
+           loss=None, loss_correlation=None,
+           dup=None, dup_correlation=None,
+           corrupt=None, corrupt_correlation=None):
     use_netem = bool(delay or delay_jitter or delay_correlation or
                      delay_distribution or loss or loss_correlation or dup or
                      dup_correlation or corrupt or corrupt_correlation)
@@ -920,10 +960,11 @@ def set_tc(iface, bandwidth = None, delay = None, delay_jitter = None,
     for c in commands:
         execute(c)
 
-def create_tap(iface, use_pi = False, tun = False):
+
+def create_tap(iface, use_pi=False, tun=False):
     """Creates a tap/tun device and returns the associated file descriptor"""
     if isinstance(iface, str):
-        iface = interface(name = iface)
+        iface = interface(name=iface)
     assert iface.name
 
     IFF_TUN = 0x0001
@@ -952,4 +993,3 @@ def create_tap(iface, use_pi = False, tun = False):
         raise
     interfaces = get_if_data()[1]
     return interfaces[iface.name], fd
-

src/nemu/node.py

@@ -21,10 +21,13 @@ import os
 import socket
 import sys
 import traceback
+from typing import MutableMapping
+
 import unshare
 import weakref
 
 import nemu.interface
+import nemu.iproute
 import nemu.protocol
 import nemu.subprocess_
 from nemu import compat
@@ -33,10 +36,11 @@ from nemu.environ import *
 __all__ = ['Node', 'get_nodes', 'import_if']
 
 class Node(object):
-    _nodes = weakref.WeakValueDictionary()
+    _nodes: MutableMapping[int, "Node"] = weakref.WeakValueDictionary()
     _nextnode = 0
+    _processes: MutableMapping[int, nemu.subprocess_.Subprocess]
     @staticmethod
-    def get_nodes():
+    def get_nodes() -> list["Node"]:
         s = sorted(list(Node._nodes.items()), key = lambda x: x[0])
         return [x[1] for x in s]
 
@@ -98,7 +102,7 @@ class Node(object):
         return self._pid
 
     # Subprocesses
-    def _add_subprocess(self, subprocess):
+    def _add_subprocess(self, subprocess: nemu.subprocess_.Subprocess):
         self._processes[subprocess.pid] = subprocess
 
     def Subprocess(self, *kargs, **kwargs):
@@ -188,13 +192,13 @@ class Node(object):
             r = self.route(*args, **kwargs)
         return self._slave.del_route(r)
 
-    def get_routes(self):
+    def get_routes(self) -> list[route]:
         return self._slave.get_route_data()
 
 # Handle the creation of the child; parent gets (fd, pid), child creates and
 # runs a Server(); never returns.
 # Requires CAP_SYS_ADMIN privileges to run.
-def _start_child(nonetns) -> (socket.socket, int):
+def _start_child(nonetns: bool) -> (socket.socket, int):
     # Create socket pair to communicate
     (s0, s1) = compat.socketpair(socket.AF_UNIX, socket.SOCK_STREAM, 0)
     # Spawn a child that will run in a loop

src/nemu/passfd.py

@@ -21,7 +21,7 @@ import struct
 from io import IOBase
 
 
-def __check_socket(sock: socket.socket | IOBase):
+def __check_socket(sock: socket.socket | IOBase) -> socket.socket:
     if hasattr(sock, 'family') and sock.family != socket.AF_UNIX:
         raise ValueError("Only AF_UNIX sockets are allowed")
 
@@ -33,7 +33,7 @@ def __check_socket(sock: socket.socket | IOBase):
 
     return sock
 
-def __check_fd(fd):
+def __check_fd(fd) -> int:
     try:
         fd = fd.fileno()
     except AttributeError:
@@ -44,7 +44,7 @@ def __check_fd(fd):
     return fd
 
 
-def recvfd(sock: socket.socket | IOBase, msg_buf: int = 4096):
+def recvfd(sock: socket.socket | IOBase, msg_buf: int = 4096) -> tuple[int, str]:
     size = struct.calcsize("@i")
     msg, ancdata, flags, addr = __check_socket(sock).recvmsg(msg_buf, socket.CMSG_SPACE(size))
     cmsg_level, cmsg_type, cmsg_data = ancdata[0]
@@ -59,7 +59,7 @@ def recvfd(sock: socket.socket | IOBase, msg_buf: int = 4096):
     return fd, msg.decode("utf-8")
 
 
-def sendfd(sock: socket.socket | IOBase, fd: int, message: bytes = b"NONE"):
+def sendfd(sock: socket.socket | IOBase, fd: int, message: bytes = b"NONE") -> int:
     return __check_socket(sock).sendmsg(
         [message],
         [(socket.SOL_SOCKET, socket.SCM_RIGHTS, struct.pack("@i", fd))])
\ No newline at end of file

src/nemu/protocol.py

@@ -29,6 +29,7 @@ import tempfile
 import time
 import traceback
 from pickle import loads, dumps
+from typing import Literal
 
 import nemu.iproute
 import nemu.subprocess_
@@ -278,7 +279,7 @@ class Server(object):
         self.reply(220, "Hello.");
         while not self._closed:
             cmd = self.readcmd()
-            if cmd == None:
+            if cmd is None:
                 continue
             try:
                 cmd[0](cmd[1], *cmd[2])
@@ -422,7 +423,7 @@ class Server(object):
         else:
             ret = nemu.subprocess_.wait(pid)
 
-        if ret != None:
+        if ret is not None:
             self._children.remove(pid)
             if pid in self._xauthfiles:
                 try:
@@ -449,7 +450,7 @@ class Server(object):
         self.reply(200, "Process signalled.")
 
     def do_IF_LIST(self, cmdname, ifnr=None):
-        if ifnr == None:
+        if ifnr is None:
             ifdata = nemu.iproute.get_if_data()[0]
         else:
             ifdata = nemu.iproute.get_if(ifnr)
@@ -479,7 +480,7 @@ class Server(object):
 
     def do_ADDR_LIST(self, cmdname, ifnr=None):
         addrdata = nemu.iproute.get_addr_data()[0]
-        if ifnr != None:
+        if ifnr is not None:
             addrdata = addrdata[ifnr]
         self.reply(200, ["# Address data follows.",
                          _b64(dumps(addrdata, protocol=2))])
@@ -652,7 +653,7 @@ class Client(object):
         stdin/stdout/stderr can only be None or a open file descriptor.
         See nemu.subprocess_.spawn for details."""
 
-        if executable == None:
+        if executable is None:
             executable = argv[0]
         params = ["PROC", "CRTE", _b64(executable)]
         for i in argv:
@@ -663,28 +664,28 @@ class Client(object):
 
         # After this, if we get an error, we have to abort the PROC
         try:
-            if user != None:
+            if user is not None:
                 self._send_cmd("PROC", "USER", _b64(user))
                 self._read_and_check_reply()
 
-            if cwd != None:
+            if cwd is not None:
                 self._send_cmd("PROC", "CWD", _b64(cwd))
                 self._read_and_check_reply()
 
-            if env != None:
+            if env is not None:
                 params = []
                 for k, v in env.items():
                     params.extend([_b64(k), _b64(v)])
                 self._send_cmd("PROC", "ENV", *params)
                 self._read_and_check_reply()
 
-            if stdin != None:
+            if stdin is not None:
                 os.set_inheritable(stdin, True)
                 self._send_fd("SIN", stdin)
-            if stdout != None:
+            if stdout is not None:
                 os.set_inheritable(stdout, True)
                 self._send_fd("SOUT", stdout)
-            if stderr != None:
+            if stderr is not None:
                 os.set_inheritable(stderr, True)
                 self._send_fd("SERR", stderr)
         except:
@@ -739,7 +740,7 @@ class Client(object):
         cmd = ["IF", "SET", interface.index]
         for k in interface.changeable_attributes:
             v = getattr(interface, k)
-            if v != None:
+            if v is not None:
                 cmd += [k, str(v)]
 
         self._send_cmd(*cmd)
@@ -761,7 +762,7 @@ class Client(object):
         data = self._read_and_check_reply()
         return loads(_db64(data.partition("\n")[2]))
 
-    def add_addr(self, ifnr, address):
+    def add_addr(self, ifnr: int, address: nemu.iproute.address):
         if hasattr(address, "broadcast") and address.broadcast:
             self._send_cmd("ADDR", "ADD", ifnr, address.address,
                            address.prefix_len, address.broadcast)
@@ -770,7 +771,7 @@ class Client(object):
                            address.prefix_len)
         self._read_and_check_reply()
 
-    def del_addr(self, ifnr, address):
+    def del_addr(self, ifnr: int, address: nemu.iproute.address):
         self._send_cmd("ADDR", "DEL", ifnr, address.address, address.prefix_len)
         self._read_and_check_reply()
 
@@ -785,14 +786,14 @@ class Client(object):
     def del_route(self, route):
         self._add_del_route("DEL", route)
 
-    def _add_del_route(self, action, route):
+    def _add_del_route(self, action: Literal["ADD", "DEL"], route: nemu.iproute.route):
         args = ["ROUT", action, _b64(route.tipe), _b64(route.prefix),
                 route.prefix_len or 0, _b64(route.nexthop),
                 route.interface or 0, route.metric or 0]
         self._send_cmd(*args)
         self._read_and_check_reply()
 
-    def set_x11(self, protoname, hexkey):
+    def set_x11(self, protoname: str, hexkey: str) -> socket.socket:
         # Returns a socket ready to accept() connections
         self._send_cmd("X11", "SET", protoname, hexkey)
         self._read_and_check_reply()
@@ -823,7 +824,7 @@ class Client(object):
 
 
 def _b64_OLD(text: str | bytes) -> str:
-    if text == None:
+    if text is None:
         # easier this way
         text = ''
     if type(text) is str:
@@ -838,6 +839,7 @@ def _b64_OLD(text: str | bytes) -> str:
     else:
         return text
 
+
 def _b64(text) -> str:
     if text is None:
         # easier this way

src/nemu/subprocess_.py

@@ -27,7 +27,10 @@ import signal
 import sys
 import time
 import traceback
+import typing
 
+if typing.TYPE_CHECKING:
+    from nemu import Node
 from nemu import compat
 from nemu.environ import eintr_wrapper
 
@@ -46,7 +49,7 @@ class Subprocess(object):
     # FIXME
     default_user = None
 
-    def __init__(self, node, argv: str | list[str], executable=None,
+    def __init__(self, node: "Node", argv: str | list[str], executable=None,
                  stdin=None, stdout=None, stderr=None,
                  shell=False, cwd=None, env=None, user=None):
         self._slave = node._slave
@@ -78,7 +81,7 @@ class Subprocess(object):
         Exceptions occurred while trying to set up the environment or executing
         the program are propagated to the parent."""
 
-        if user == None:
+        if user is None:
             user = Subprocess.default_user
 
         if isinstance(argv, str):
@@ -106,20 +109,20 @@ class Subprocess(object):
     def poll(self):
         """Checks status of program, returns exitcode or None if still running.
         See Popen.poll."""
-        if self._returncode == None:
+        if self._returncode is None:
             self._returncode = self._slave.poll(self._pid)
         return self.returncode
 
     def wait(self):
         """Waits for program to complete and returns the exitcode.
         See Popen.wait"""
-        if self._returncode == None:
+        if self._returncode is None:
             self._returncode = self._slave.wait(self._pid)
         return self.returncode
 
     def signal(self, sig=signal.SIGTERM):
         """Sends a signal to the process."""
-        if self._returncode == None:
+        if self._returncode is None:
             self._slave.signal(self._pid, sig)
 
     @property
@@ -128,7 +131,7 @@ class Subprocess(object):
         communicate, wait, or poll), returns the signal that killed the
         program, if negative; otherwise, it is the exit code of the program.
         """
-        if self._returncode == None:
+        if self._returncode is None:
             return None
         if os.WIFSIGNALED(self._returncode):
             return -os.WTERMSIG(self._returncode)
@@ -140,12 +143,12 @@ class Subprocess(object):
         self.destroy()
 
     def destroy(self):
-        if self._returncode != None or self._pid == None:
+        if self._returncode is not None or self._pid is None:
             return
         self.signal()
         now = time.time()
         while time.time() - now < KILL_WAIT:
-            if self.poll() != None:
+            if self.poll() is not None:
                 return
             time.sleep(0.1)
         sys.stderr.write("WARNING: killing forcefully process %d.\n" %
@@ -179,7 +182,7 @@ class Popen(Subprocess):
         fdmap = {"stdin": stdin, "stdout": stdout, "stderr": stderr}
         # if PIPE: all should be closed at the end
         for k, v in fdmap.items():
-            if v == None:
+            if v is None:
                 continue
             if v == PIPE:
                 r, w = compat.pipe()
@@ -206,27 +209,29 @@ class Popen(Subprocess):
 
         # Close pipes, they have been dup()ed to the child
         for k, v in fdmap.items():
-            if getattr(self, k) != None:
+            if getattr(self, k) is not None:
                 eintr_wrapper(os.close, v)
 
-    def communicate(self, input: bytes = None) -> tuple[bytes, bytes]:
+    def communicate(self, input: bytes | str = None) -> tuple[bytes, bytes]:
         """See Popen.communicate."""
         # FIXME: almost verbatim from stdlib version, need to be removed or
         # something
+        if type(input) is str:
+            input = input.encode("utf-8")
         wset = []
         rset = []
         err = None
         out = None
-        if self.stdin != None:
+        if self.stdin is not None:
             self.stdin.flush()
             if input:
                 wset.append(self.stdin)
             else:
                 self.stdin.close()
-        if self.stdout != None:
+        if self.stdout is not None:
             rset.append(self.stdout)
             out = []
-        if self.stderr != None:
+        if self.stderr is not None:
             rset.append(self.stderr)
             err = []
 
@@ -253,9 +258,9 @@ class Popen(Subprocess):
                         else:
                             err.append(d)
 
-        if out != None:
+        if out is not None:
             out = b''.join(out)
-        if err != None:
+        if err is not None:
             err = b''.join(err)
         self.wait()
         return (out, err)
@@ -313,15 +318,15 @@ def spawn(executable, argv=None, cwd=None, env=None, close_fds=False,
     is not supported here. Also, the original descriptors are not closed.
     """
     userfd = [stdin, stdout, stderr]
-    filtered_userfd = [x for x in userfd if x != None and x >= 0]
+    filtered_userfd = [x for x in userfd if x is not None and x >= 0]
     for i in range(3):
-        if userfd[i] != None and not isinstance(userfd[i], int):
+        if userfd[i] is not None and not isinstance(userfd[i], int):
             userfd[i] = userfd[i].fileno()  # pragma: no cover
 
     # Verify there is no clash
     assert not (set([0, 1, 2]) & set(filtered_userfd))
 
-    if user != None:
+    if user is not None:
         user, uid, gid = get_user(user)
         home = pwd.getpwuid(uid)[5]
         groups = [x[2] for x in grp.getgrall() if user in x[3]]
@@ -337,7 +342,7 @@ def spawn(executable, argv=None, cwd=None, env=None, close_fds=False,
         try:
             # Set up stdio piping
             for i in range(3):
-                if userfd[i] != None and userfd[i] >= 0:
+                if userfd[i] is not None and userfd[i] >= 0:
                     os.dup2(userfd[i], i)
                     if userfd[i] != i and userfd[i] not in userfd[0:i]:
                         eintr_wrapper(os.close, userfd[i])  # only in child!
@@ -362,22 +367,22 @@ def spawn(executable, argv=None, cwd=None, env=None, close_fds=False,
             # (it is necessary to kill the forked subprocesses)
             os.setpgrp()
 
-            if user != None:
+            if user is not None:
                 # Change user
                 os.setgid(gid)
                 os.setgroups(groups)
                 os.setuid(uid)
-            if cwd != None:
+            if cwd is not None:
                 os.chdir(cwd)
             if not argv:
                 argv = [executable]
             if '/' in executable:  # Should not search in PATH
-                if env != None:
+                if env is not None:
                     os.execve(executable, argv, env)
                 else:
                     os.execv(executable, argv)
             else:  # use PATH
-                if env != None:
+                if env is not None:
                     os.execvpe(executable, argv, env)
                 else:
                     os.execvp(executable, argv)

test/test_core.py

@@ -136,7 +136,7 @@ class TestGlobal(unittest.TestCase):
                     os.write(if1.fd, s)
                 if not s:
                     break
-            if subproc.poll() != None:
+            if subproc.poll() is not None:
                 break
 
     @test_util.skipUnless(os.getuid() == 0, "Test requires root privileges")

test/test_protocol.py

@@ -107,7 +107,7 @@ class TestServer(unittest.TestCase):
         def check_ok(self, cmd, func, args):
             s1.write("%s\n" % cmd)
             ccmd = " ".join(cmd.upper().split()[0:2])
-            if func == None:
+            if func is None:
                 self.assertEqual(srv.readcmd()[1:3], (ccmd, args))
             else:
                 self.assertEqual(srv.readcmd(), (func, ccmd, args))

test/test_util.py

@@ -15,7 +15,7 @@ def process_ipcmd(str: str):
         match = re.search(r'^(\d+): ([^@\s]+)(?:@\S+)?: <(\S+)> mtu (\d+) '
                           r'qdisc (\S+)',
                 line)
-        if match != None:
+        if match is not None:
             cur = match.group(2)
             out[cur] = {
                     'idx':      int(match.group(1)),
@@ -27,14 +27,14 @@ def process_ipcmd(str: str):
             out[cur]['up'] = 'UP' in out[cur]['flags']
             continue
         # Assume cur is defined
-        assert cur != None
+        assert cur is not None
         match = re.search(r'^\s+link/\S*(?: ([0-9a-f:]+))?(?: |$)', line)
-        if match != None:
+        if match is not None:
             out[cur]['lladdr'] = match.group(1)
             continue
 
         match = re.search(r'^\s+inet ([0-9.]+)/(\d+)(?: brd ([0-9.]+))?', line)
-        if match != None:
+        if match is not None:
             out[cur]['addr'].append({
                 'address': match.group(1),
                 'prefix_len': int(match.group(2)),
@@ -43,7 +43,7 @@ def process_ipcmd(str: str):
             continue
 
         match = re.search(r'^\s+inet6 ([0-9a-f:]+)/(\d+)(?: |$)', line)
-        if match != None:
+        if match is not None:
             out[cur]['addr'].append({
                 'address': match.group(1),
                 'prefix_len': int(match.group(2)),
@@ -51,7 +51,7 @@ def process_ipcmd(str: str):
             continue
 
         match = re.search(r'^\s{4}', line)
-        assert match != None
+        assert match is not None
     return out
 
 def get_devs():