nsim.py

  1# SPDX-License-Identifier: GPL-2.0
  2
  3import errno
  4import json
  5import os
  6import random
  7import re
  8import time
  9from .utils import cmd, ip
 10
 11
 12class NetdevSim:
 13    """
 14    Class for netdevsim netdevice and its attributes.
 15    """
 16
 17    def __init__(self, nsimdev, port_index, ifname, ns=None):
 18        # In case udev renamed the netdev to according to new schema,
 19        # check if the name matches the port_index.
 20        nsimnamere = re.compile(r"eni\d+np(\d+)")
 21        match = nsimnamere.match(ifname)
 22        if match and int(match.groups()[0]) != port_index + 1:
 23            raise Exception("netdevice name mismatches the expected one")
 24
 25        self.ifname = ifname
 26        self.nsimdev = nsimdev
 27        self.port_index = port_index
 28        self.ns = ns
 29        self.dfs_dir = "%s/ports/%u/" % (nsimdev.dfs_dir, port_index)
 30        ret = ip("-d -j link show dev %s" % ifname, ns=ns)
 31        self.dev = json.loads(ret.stdout)[0]
 32        self.ifindex = self.dev["ifindex"]
 33
 34    def dfs_write(self, path, val):
 35        self.nsimdev.dfs_write(f'ports/{self.port_index}/' + path, val)
 36
 37
 38class NetdevSimDev:
 39    """
 40    Class for netdevsim bus device and its attributes.
 41    """
 42    @staticmethod
 43    def ctrl_write(path, val):
 44        fullpath = os.path.join("/sys/bus/netdevsim/", path)
 45        with open(fullpath, "w") as f:
 46            f.write(val)
 47
 48    def dfs_write(self, path, val):
 49        fullpath = os.path.join(f"/sys/kernel/debug/netdevsim/netdevsim{self.addr}/", path)
 50        with open(fullpath, "w") as f:
 51            f.write(val)
 52
 53    def __init__(self, port_count=1, queue_count=1, ns=None):
 54        # nsim will spawn in init_net, we'll set to actual ns once we switch it there
 55        self.ns = None
 56
 57        if not os.path.exists("/sys/bus/netdevsim"):
 58            cmd("modprobe netdevsim")
 59
 60        addr = random.randrange(1 << 15)
 61        while True:
 62            try:
 63                self.ctrl_write("new_device", "%u %u %u" % (addr, port_count, queue_count))
 64            except OSError as e:
 65                if e.errno == errno.ENOSPC:
 66                    addr = random.randrange(1 << 15)
 67                    continue
 68                raise e
 69            break
 70        self.addr = addr
 71
 72        # As probe of netdevsim device might happen from a workqueue,
 73        # so wait here until all netdevs appear.
 74        self.wait_for_netdevs(port_count)
 75
 76        if ns:
 77            cmd(f"devlink dev reload netdevsim/netdevsim{addr} netns {ns.name}")
 78            self.ns = ns
 79
 80        cmd("udevadm settle", ns=self.ns)
 81        ifnames = self.get_ifnames()
 82
 83        self.dfs_dir = "/sys/kernel/debug/netdevsim/netdevsim%u/" % addr
 84
 85        self.nsims = []
 86        for port_index in range(port_count):
 87            self.nsims.append(self._make_port(port_index, ifnames[port_index]))
 88
 89        self.removed = False
 90
 91    def __enter__(self):
 92        return self
 93
 94    def __exit__(self, ex_type, ex_value, ex_tb):
 95        """
 96        __exit__ gets called at the end of a "with" block.
 97        """
 98        self.remove()
 99
100    def _make_port(self, port_index, ifname):
101        return NetdevSim(self, port_index, ifname, self.ns)
102
103    def get_ifnames(self):
104        ifnames = []
105        listdir = cmd(f"ls /sys/bus/netdevsim/devices/netdevsim{self.addr}/net/",
106                      ns=self.ns).stdout.split()
107        for ifname in listdir:
108            ifnames.append(ifname)
109        ifnames.sort()
110        return ifnames
111
112    def wait_for_netdevs(self, port_count):
113        timeout = 5
114        timeout_start = time.time()
115
116        while True:
117            try:
118                ifnames = self.get_ifnames()
119            except FileNotFoundError as e:
120                ifnames = []
121            if len(ifnames) == port_count:
122                break
123            if time.time() < timeout_start + timeout:
124                continue
125            raise Exception("netdevices did not appear within timeout")
126
127    def remove(self):
128        if not self.removed:
129            self.ctrl_write("del_device", "%u" % (self.addr, ))
130            self.removed = True
131
132    def remove_nsim(self, nsim):
133        self.nsims.remove(nsim)
134        self.ctrl_write("devices/netdevsim%u/del_port" % (self.addr, ),
135                        "%u" % (nsim.port_index, ))