#!/usr/bin/env python3# SPDX-License-Identifier: GPL-2.0 import socketimport timefrom lib.py import bkg, ip, ksft_exit, ksft_run, ksft_ge, ksft_true, KsftSkipExfrom lib.py import CmdExitFailure, NetNS, NetNSEnter, RtnlAddrFamily IPV4_ALL_HOSTS_MULTICAST = b'\xe0\x00\x00\x01' def dump_mcaddr_check() -> None:    """    Verify that at least one interface has the IPv4 all-hosts multicast address.    At least the loopback interface should have this address.    """     rtnl = RtnlAddrFamily()    addresses = rtnl.getmulticast({"ifa-family": socket.AF_INET}, dump=True)     all_host_multicasts = [        addr for addr in addresses if addr['multicast'] == IPV4_ALL_HOSTS_MULTICAST    ]     ksft_ge(len(all_host_multicasts), 1,            "No interface found with the IPv4 all-hosts multicast address") def ipv4_devconf_notify() -> None:    """    Configure an interface and set ipv4-devconf values through netlink    to verify that the appropriate netlink notifications are being sent.    """     with NetNS() as ns:        with NetNSEnter(str(ns)):            ifname = "dummy1"            ip(f"link add name {ifname} type dummy", ns=str(ns))             with bkg("ip monitor", ns=str(ns)) as cmd_obj:                time.sleep(1)                try:                    ip(f"link set dev {ifname} inet forwarding on")                    ip(f"link set dev {ifname} inet proxy_arp on")                    ip(f"link set dev {ifname} inet rp_filter 1")                    ip(f"link set dev {ifname} inet ignore_routes_with_linkdown on")                except CmdExitFailure:                    raise KsftSkipEx("iproute2 does not support IPv4 devconf attributes")                time.sleep(1)     ksft_true(f"inet {ifname} ignore_routes_with_linkdown on" in cmd_obj.stdout,              f"No 'ignore_routes_with_linkdown on' notificiation found for interface {ifname}")    ksft_true(f"inet {ifname} rp_filter strict" in cmd_obj.stdout,              f"No 'rp_filter strict' notificiation found for interface {ifname}")    ksft_true(f"inet {ifname} proxy_neigh on" in cmd_obj.stdout,              f"No 'proxy_neigh on' notificiation found for interface {ifname}")    ksft_true(f"inet {ifname} forwarding on" in cmd_obj.stdout,              f"No 'forwarding on' notificiation found for interface {ifname}") def main() -> None:    ksft_run([dump_mcaddr_check, ipv4_devconf_notify])    ksft_exit() if __name__ == "__main__":    main()