Merge branch 'selftests-drv-net-support-testing-with-a-remote-system'

Jakub Kicinski says:

====================
selftests: drv-net: support testing with a remote system

Implement support for tests which require access to a remote system /
endpoint which can generate traffic.
This series concludes the "groundwork" for upstream driver tests.

I wanted to support the three models which came up in discussions:
 - SW testing with netdevsim
 - "local" testing with two ports on the same system in a loopback
 - "remote" testing via SSH
so there is a tiny bit of an abstraction which wraps up how "remote"
commands are executed. Otherwise hopefully there's nothing surprising.

I'm only adding a ping test. I had a bigger one written but I was
worried we'll get into discussing the details of the test itself
and how I chose to hack up netdevsim, instead of the test infra...
So that test will be a follow up :)

v4: https://lore.kernel.org/all/20240418233844.2762396-1-kuba@kernel.org
v3: https://lore.kernel.org/all/20240417231146.2435572-1-kuba@kernel.org
v2: https://lore.kernel.org/all/20240416004556.1618804-1-kuba@kernel.org
v1: https://lore.kernel.org/all/20240412233705.1066444-1-kuba@kernel.org
====================

Link: https://lore.kernel.org/r/20240420025237.3309296-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

tools/testing/selftests/drivers/net/Makefile

@@ -2,6 +2,9 @@
 
 TEST_INCLUDES := $(wildcard lib/py/*.py)
 
-TEST_PROGS := stats.py
+TEST_PROGS := \
+	ping.py \
+	stats.py \
+# end of TEST_PROGS
 
 include ../../lib.mk

tools/testing/selftests/drivers/net/README.rst

@@ -23,8 +23,41 @@ or::
   # Variable set in a file
   NETIF=eth0
 
+Please note that the config parser is very simple, if there are
+any non-alphanumeric characters in the value it needs to be in
+double quotes.
+
 NETIF
 ~~~~~
 
 Name of the netdevice against which the test should be executed.
 When empty or not set software devices will be used.
+
+LOCAL_V4, LOCAL_V6, REMOTE_V4, REMOTE_V6
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Local and remote endpoint IP addresses.
+
+REMOTE_TYPE
+~~~~~~~~~~~
+
+Communication method used to run commands on the remote endpoint.
+Test framework has built-in support for ``netns`` and ``ssh`` channels.
+``netns`` assumes the "remote" interface is part of the same
+host, just moved to the specified netns.
+``ssh`` communicates with remote endpoint over ``ssh`` and ``scp``.
+Using persistent SSH connections is strongly encouraged to avoid
+the latency of SSH connection setup on every command.
+
+Communication methods are defined by classes in ``lib/py/remote_{name}.py``.
+It should be possible to add a new method without modifying any of
+the framework, by simply adding an appropriately named file to ``lib/py``.
+
+REMOTE_ARGS
+~~~~~~~~~~~
+
+Arguments used to construct the communication channel.
+Communication channel dependent::
+
+  for netns - name of the "remote" namespace
+  for ssh - name/address of the remote host

tools/testing/selftests/drivers/net/lib/py/__init__.py

@@ -15,3 +15,4 @@
     sys.exit(4)
 
 from .env import *
+from .remote import Remote

tools/testing/selftests/drivers/net/lib/py/env.py

@@ -3,15 +3,41 @@
 import os
 import shlex
 from pathlib import Path
-from lib.py import ip
-from lib.py import NetdevSimDev
+from lib.py import KsftSkipEx
+from lib.py import cmd, ip
+from lib.py import NetNS, NetdevSimDev
+from .remote import Remote
+
+
+def _load_env_file(src_path):
+    env = os.environ.copy()
+
+    src_dir = Path(src_path).parent.resolve()
+    if not (src_dir / "net.config").exists():
+        return env
+
+    lexer = shlex.shlex(open((src_dir / "net.config").as_posix(), 'r').read())
+    k = None
+    for token in lexer:
+        if k is None:
+            k = token
+            env[k] = ""
+        elif token == "=":
+            pass
+        else:
+            env[k] = token
+            k = None
+    return env
+
 
 class NetDrvEnv:
+    """
+    Class for a single NIC / host env, with no remote end
+    """
     def __init__(self, src_path):
         self._ns = None
 
-        self.env = os.environ.copy()
-        self._load_env_file(src_path)
+        self.env = _load_env_file(src_path)
 
         if 'NETIF' in self.env:
             self.dev = ip("link show dev " + self.env['NETIF'], json=True)[0]
@@ -34,19 +60,130 @@ def __del__(self):
             self._ns.remove()
             self._ns = None
 
-    def _load_env_file(self, src_path):
-        src_dir = Path(src_path).parent.resolve()
-        if not (src_dir / "net.config").exists():
-            return
-
-        lexer = shlex.shlex(open((src_dir / "net.config").as_posix(), 'r').read())
-        k = None
-        for token in lexer:
-            if k is None:
-                k = token
-                self.env[k] = ""
-            elif token == "=":
-                pass
-            else:
-                self.env[k] = token
-                k = None
+
+class NetDrvEpEnv:
+    """
+    Class for an environment with a local device and "remote endpoint"
+    which can be used to send traffic in.
+
+    For local testing it creates two network namespaces and a pair
+    of netdevsim devices.
+    """
+
+    # Network prefixes used for local tests
+    nsim_v4_pfx = "192.0.2."
+    nsim_v6_pfx = "2001:db8::"
+
+    def __init__(self, src_path):
+
+        self.env = _load_env_file(src_path)
+
+        # Things we try to destroy
+        self.remote = None
+        # These are for local testing state
+        self._netns = None
+        self._ns = None
+        self._ns_peer = None
+
+        if "NETIF" in self.env:
+            self.dev = ip("link show dev " + self.env['NETIF'], json=True)[0]
+
+            self.v4 = self.env.get("LOCAL_V4")
+            self.v6 = self.env.get("LOCAL_V6")
+            self.remote_v4 = self.env.get("REMOTE_V4")
+            self.remote_v6 = self.env.get("REMOTE_V6")
+            kind = self.env["REMOTE_TYPE"]
+            args = self.env["REMOTE_ARGS"]
+        else:
+            self.create_local()
+
+            self.dev = self._ns.nsims[0].dev
+
+            self.v4 = self.nsim_v4_pfx + "1"
+            self.v6 = self.nsim_v6_pfx + "1"
+            self.remote_v4 = self.nsim_v4_pfx + "2"
+            self.remote_v6 = self.nsim_v6_pfx + "2"
+            kind = "netns"
+            args = self._netns.name
+
+        self.remote = Remote(kind, args, src_path)
+
+        self.addr = self.v6 if self.v6 else self.v4
+        self.remote_addr = self.remote_v6 if self.remote_v6 else self.remote_v4
+
+        self.addr_ipver = "6" if self.v6 else "4"
+        # Bracketed addresses, some commands need IPv6 to be inside []
+        self.baddr = f"[{self.v6}]" if self.v6 else self.v4
+        self.remote_baddr = f"[{self.remote_v6}]" if self.remote_v6 else self.remote_v4
+
+        self.ifname = self.dev['ifname']
+        self.ifindex = self.dev['ifindex']
+
+        self._required_cmd = {}
+
+    def create_local(self):
+        self._netns = NetNS()
+        self._ns = NetdevSimDev()
+        self._ns_peer = NetdevSimDev(ns=self._netns)
+
+        with open("/proc/self/ns/net") as nsfd0, \
+             open("/var/run/netns/" + self._netns.name) as nsfd1:
+            ifi0 = self._ns.nsims[0].ifindex
+            ifi1 = self._ns_peer.nsims[0].ifindex
+            NetdevSimDev.ctrl_write('link_device',
+                                    f'{nsfd0.fileno()}:{ifi0} {nsfd1.fileno()}:{ifi1}')
+
+        ip(f"   addr add dev {self._ns.nsims[0].ifname} {self.nsim_v4_pfx}1/24")
+        ip(f"-6 addr add dev {self._ns.nsims[0].ifname} {self.nsim_v6_pfx}1/64 nodad")
+        ip(f"   link set dev {self._ns.nsims[0].ifname} up")
+
+        ip(f"   addr add dev {self._ns_peer.nsims[0].ifname} {self.nsim_v4_pfx}2/24", ns=self._netns)
+        ip(f"-6 addr add dev {self._ns_peer.nsims[0].ifname} {self.nsim_v6_pfx}2/64 nodad", ns=self._netns)
+        ip(f"   link set dev {self._ns_peer.nsims[0].ifname} up", ns=self._netns)
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, ex_type, ex_value, ex_tb):
+        """
+        __exit__ gets called at the end of a "with" block.
+        """
+        self.__del__()
+
+    def __del__(self):
+        if self._ns:
+            self._ns.remove()
+            self._ns = None
+        if self._ns_peer:
+            self._ns_peer.remove()
+            self._ns_peer = None
+        if self._netns:
+            del self._netns
+            self._netns = None
+        if self.remote:
+            del self.remote
+            self.remote = None
+
+    def require_v4(self):
+        if not self.v4 or not self.remote_v4:
+            raise KsftSkipEx("Test requires IPv4 connectivity")
+
+    def require_v6(self):
+        if not self.v6 or not self.remote_v6:
+            raise KsftSkipEx("Test requires IPv6 connectivity")
+
+    def _require_cmd(self, comm, key, host=None):
+        cached = self._required_cmd.get(comm, {})
+        if cached.get(key) is None:
+            cached[key] = cmd("command -v -- " + comm, fail=False,
+                              shell=True, host=host).ret == 0
+        self._required_cmd[comm] = cached
+        return cached[key]
+
+    def require_cmd(self, comm, local=True, remote=False):
+        if local:
+            if not self._require_cmd(comm, "local"):
+                raise KsftSkipEx("Test requires command: " + comm)
+        if remote:
+            if not self._require_cmd(comm, "remote"):
+                raise KsftSkipEx("Test requires (remote) command: " + comm)

tools/testing/selftests/drivers/net/lib/py/remote.py

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0
+
+import os
+import importlib
+
+_modules = {}
+
+def Remote(kind, args, src_path):
+    global _modules
+
+    if kind not in _modules:
+        _modules[kind] = importlib.import_module("..remote_" + kind, __name__)
+
+    dir_path = os.path.abspath(src_path + "/../")
+    return getattr(_modules[kind], "Remote")(args, dir_path)

tools/testing/selftests/drivers/net/lib/py/remote_netns.py

@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0
+
+import os
+import subprocess
+
+from lib.py import cmd
+
+
+class Remote:
+    def __init__(self, name, dir_path):
+        self.name = name
+        self.dir_path = dir_path
+
+    def cmd(self, comm):
+        return subprocess.Popen(["ip", "netns", "exec", self.name, "bash", "-c", comm],
+                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+    def deploy(self, what):
+        if os.path.isabs(what):
+            return what
+        return os.path.abspath(self.dir_path + "/" + what)

tools/testing/selftests/drivers/net/lib/py/remote_ssh.py

@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0
+
+import os
+import string
+import subprocess
+import random
+
+from lib.py import cmd
+
+
+class Remote:
+    def __init__(self, name, dir_path):
+        self.name = name
+        self.dir_path = dir_path
+        self._tmpdir = None
+
+    def __del__(self):
+        if self._tmpdir:
+            cmd("rm -rf " + self._tmpdir, host=self)
+            self._tmpdir = None
+
+    def cmd(self, comm):
+        return subprocess.Popen(["ssh", "-q", self.name, comm],
+                                stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+    def _mktmp(self):
+        return ''.join(random.choice(string.ascii_lowercase) for _ in range(8))
+
+    def deploy(self, what):
+        if not self._tmpdir:
+            self._tmpdir = "/tmp/" + self._mktmp()
+            cmd("mkdir " + self._tmpdir, host=self)
+        file_name = self._tmpdir + "/" + self._mktmp() + os.path.basename(what)
+
+        if not os.path.isabs(what):
+            what = os.path.abspath(self.dir_path + "/" + what)
+
+        cmd(f"scp {what} {self.name}:{file_name}")
+        return file_name

tools/testing/selftests/drivers/net/ping.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+from lib.py import ksft_run, ksft_exit
+from lib.py import ksft_eq
+from lib.py import NetDrvEpEnv
+from lib.py import bkg, cmd, wait_port_listen, rand_port
+
+
+def test_v4(cfg) -> None:
+    cfg.require_v4()
+
+    cmd(f"ping -c 1 -W0.5 {cfg.remote_v4}")
+    cmd(f"ping -c 1 -W0.5 {cfg.v4}", host=cfg.remote)
+
+
+def test_v6(cfg) -> None:
+    cfg.require_v6()
+
+    cmd(f"ping -c 1 -W0.5 {cfg.remote_v6}")
+    cmd(f"ping -c 1 -W0.5 {cfg.v6}", host=cfg.remote)
+
+
+def test_tcp(cfg) -> None:
+    cfg.require_cmd("socat", remote=True)
+
+    port = rand_port()
+    listen_cmd = f"socat -{cfg.addr_ipver} -t 2 -u TCP-LISTEN:{port},reuseport STDOUT"
+
+    with bkg(listen_cmd, exit_wait=True) as nc:
+        wait_port_listen(port)
+
+        cmd(f"echo ping | socat -t 2 -u STDIN TCP:{cfg.baddr}:{port}",
+            shell=True, host=cfg.remote)
+    ksft_eq(nc.stdout.strip(), "ping")
+
+    with bkg(listen_cmd, host=cfg.remote, exit_wait=True) as nc:
+        wait_port_listen(port, host=cfg.remote)
+
+        cmd(f"echo ping | socat -t 2 -u STDIN TCP:{cfg.remote_baddr}:{port}", shell=True)
+    ksft_eq(nc.stdout.strip(), "ping")
+
+
+def main() -> None:
+    with NetDrvEpEnv(__file__) as cfg:
+        ksft_run(globs=globals(), case_pfx={"test_"}, args=(cfg, ))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()

tools/testing/selftests/net/lib/py/__init__.py

@@ -2,6 +2,7 @@
 
 from .consts import KSRC
 from .ksft import *
+from .netns import NetNS
 from .nsim import *
 from .utils import *
 from .ynl import NlError, YnlFamily, EthtoolFamily, NetdevFamily, RtnlFamily