#! /usr/bin/python3

# SPDX-License-Identifier: GPL-2.0-or-later
#
# tasst - Test A Simple Socket Transport
#         library of test helpers for passt & pasta
#
# tasst/scenario/simple - Smallest sensible network to use passt/pasta
#
# Copyright Red Hat
# Author: David Gibson <david@gibson.dropbear.id.au>

import contextlib

from tasst import Tasst
from tasst.nstool import UnshareSite
from tasst.address import IpiAllocator, TEST_NET_2, TEST_NET6_TASST_B
from tasst.site import Site
from tasst.transfer import MetaTcpUploadTasst, MetaUdpTransferTasst, TransferTasstInfo
from tasst.typing import typecheck


class __SimpleNet:
    """A simple network setup scenario

    The sample network has 2 sites (network namespaces) connected with
    a veth link:
            [simhost]   <-veth->    [gw]

    gw is set up as the default router for simhost.

    simhost has addresses:
        self.ip4 (IPv4), self.ip6 (IPv6), self.ip6_ll (IPv6 link local)

    gw has addresses:
        self.gw_ip4 (IPv4), self.gw_ip6 (IPv6), self.gw_ip6_ll (IPv6 link local)
        self.remote_ip4 (IPv4), self.remote_ip6 (IPv6)

    The "remote" addresses are on a different subnet from the others,
    so the only way for simhost to reach them is via its default
    route.  This helps to exercise that we're actually using that,
    rather than just local net routes.

    """

    def __init__(self, hostsite, gwsite):
        self.simhost = typecheck(hostsite, Site)
        self.gw = typecheck(gwsite, Site)

        self.ifname = 'veth'
        self.gw_ifname = 'gw' + self.ifname
        self.simhost.veth(self.ifname, self.gw_ifname, self.gw)

        ipa_local = IpiAllocator()
        self.ip4, self.ip6 = ipa_local.next_ipis()
        self.gw_ip4, self.gw_ip6 = ipa_local.next_ipis()

        ipa_remote = IpiAllocator(TEST_NET_2, TEST_NET6_TASST_B)
        self.remote_ip4, self.remote_ip6 = ipa_remote.next_ipis()

        self.gw.ifup('lo')
        self.gw.ifup(self.gw_ifname, self.gw_ip4, self.gw_ip6,
                     self.remote_ip4, self.remote_ip6)

        self.simhost.ifup('lo')
        self.simhost.ifup(self.ifname, self.ip4, self.ip6)

        # Once link is up on both sides, SLAAC will run
        self.gw_ip6_ll = self.gw.addr_wait(self.gw_ifname, family='inet6', scope='link')[0]
        self.ip6_ll = self.simhost.addr_wait(self.ifname, family='inet6', scope='link')[0]

        # Set up the default route
        self.simhost.fg('ip -4 route add default via {}'.format(self.gw_ip4.ip), sudo=True)
        self.simhost.fg('ip -6 route add default via {} dev {}'
                        .format(self.gw_ip6_ll.ip, self.ifname), sudo=True)

@contextlib.contextmanager
def simple_net(name):
    name = typecheck(name, str)
    with UnshareSite(name + '.simhost', '-Ucnpf --mount-proc') as simhost, \
         UnshareSite(name + '.gw', '-n', parent=simhost, sudo=True) as gw:
        yield __SimpleNet(simhost, gw)


class SimpleNetConnectivityTasst(MetaTcpUploadTasst, MetaUdpTransferTasst):
    """
    Check connectivity between the simulated host and the gateway,
    before involving passt/pasta.

    :avocado: tags=meta

    """

    @contextlib.contextmanager
    def setup_transfer(self):
        with simple_net(type(self).__name__) as simnet:
            yield TransferTasstInfo('test/small.bin', simnet.simhost, simnet.gw,
                                    simnet.remote_ip4.ip, simnet.remote_ip6.ip, 10000)