[PATCH v3 14/15] tasst: Helpers to construct a simple network environment for tests

[David Gibson <david@gibson.dropbear.id.au>]

This constructs essentially the simplest sensible network for passt/pasta
to operate in.  We have one netns "simhost" to represent the host where we
will run passt or pasta, and a second "gw" to represent its default
gateway.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 test/tasst/__main__.py          |   1 +
 test/tasst/scenario/__init__.py |  12 ++++
 test/tasst/scenario/simple.py   | 108 ++++++++++++++++++++++++++++++++
 3 files changed, 121 insertions(+)
 create mode 100644 test/tasst/scenario/__init__.py
 create mode 100644 test/tasst/scenario/simple.py

diff --git a/test/tasst/__main__.py b/test/tasst/__main__.py
index f94001e7..7e343492 100644
--- a/test/tasst/__main__.py
+++ b/test/tasst/__main__.py
@@ -20,6 +20,7 @@ MODULES = [
     'dhcp',
     'ip',
     'ndp',
+    'scenario.simple',
     'transfer',
     'unshare',
     'veth',
diff --git a/test/tasst/scenario/__init__.py b/test/tasst/scenario/__init__.py
new file mode 100644
index 00000000..4ea4584d
--- /dev/null
+++ b/test/tasst/scenario/__init__.py
@@ -0,0 +1,12 @@
+#! /usr/bin/python3
+
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright Red Hat
+# Author: David Gibson <david@gibson.dropbear.id.au>
+
+"""
+Test A Simple Socket Transport
+
+scenario/ - Helpers to set up various sample network topologies
+"""
diff --git a/test/tasst/scenario/simple.py b/test/tasst/scenario/simple.py
new file mode 100644
index 00000000..6ae3540a
--- /dev/null
+++ b/test/tasst/scenario/simple.py
@@ -0,0 +1,108 @@
+#! /usr/bin/env python3
+
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright Red Hat
+# Author: David Gibson <david@gibson.dropbear.id.au>
+
+"""
+Test A Simple Socket Transport
+
+scenario/simple.py - Smallest sensible network to use passt/pasta
+"""
+
+import contextlib
+from typing import Iterator
+
+from .. import ip, transfer, unshare, veth
+
+
+class __SimpleNet:  # pylint: disable=R0903
+    """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.
+
+    """
+
+    IFNAME = 'veth'
+    GW_IFNAME = 'gw' + IFNAME
+    ipa_local = ip.IpiAllocator()
+    (IP4, IP6) = ipa_local.next_ipis()
+    (GW_IP4, GW_IP6) = ipa_local.next_ipis()
+
+    ipa_remote = ip.IpiAllocator(ip.TEST_NET_2,
+                                 ip.TEST_NET6_TASST_B)
+    (REMOTE_IP4, REMOTE_IP6) = ipa_remote.next_ipis()
+
+    simhost: unshare.Unshare
+    gw: unshare.Unshare
+
+    def __init__(self, simhost: unshare.Unshare, gw: unshare.Unshare) -> None:
+        self.simhost = simhost
+        self.gw = gw
+
+        ip.ifup(self.gw, 'lo')
+        ip.ifup(self.gw, self.GW_IFNAME, self.GW_IP4, self.GW_IP6,
+                self.REMOTE_IP4, self.REMOTE_IP6)
+
+        ip.ifup(simhost, 'lo')
+        ip.ifup(simhost, self.IFNAME, self.IP4, self.IP6)
+
+        # Once link is up on both sides, SLAAC will run
+        self.gw_ip6_ll = ip.addr_wait(self.gw, self.GW_IFNAME,
+                                      family='inet6', scope='link')[0]
+        self.ip6_ll = ip.addr_wait(self.simhost, self.IFNAME,
+                                   family='inet6', scope='link')[0]
+
+        # Set up the default route
+        self.simhost.fg('ip', '-4', 'route', 'add', 'default',
+                        'via', f'{self.GW_IP4.ip}', privilege=True)
+        self.simhost.fg('ip', '-6', 'route', 'add', 'default',
+                        'via', f'{self.gw_ip6_ll.ip}', 'dev', self.IFNAME,
+                        privilege=True)
+
+
+@contextlib.contextmanager
+def simple_net() -> Iterator[__SimpleNet]:
+    with unshare.unshare('simhost', '-Ucnpf', '--mount-proc') as simhost, \
+         unshare.unshare('gw', '-n', parent=simhost, privilege=True) as gw, \
+         veth.veth(simhost, __SimpleNet.IFNAME, __SimpleNet.GW_IFNAME, gw):
+        yield __SimpleNet(simhost, gw)
+
+
+def simple_transfer4() -> Iterator[transfer.TransferScenario]:
+    with simple_net() as snet:
+        yield transfer.TransferScenario(client=snet.simhost,
+                                        server=snet.gw,
+                                        connect_ip=snet.REMOTE_IP4.ip,
+                                        connect_port=10000)
+
+
+def simple_transfer6() -> Iterator[transfer.TransferScenario]:
+    with simple_net() as snet:
+        yield transfer.TransferScenario(client=snet.simhost,
+                                        server=snet.gw,
+                                        connect_ip=snet.REMOTE_IP6.ip,
+                                        connect_port=10000)
+
+
+def selftests() -> None:
+    transfer.TransferScenario.test(simple_transfer4)
+    transfer.TransferScenario.test(simple_transfer6)
-- 
@@ -0,0 +1,108 @@
+#! /usr/bin/env python3
+
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright Red Hat
+# Author: David Gibson <david@gibson.dropbear.id.au>
+
+"""
+Test A Simple Socket Transport
+
+scenario/simple.py - Smallest sensible network to use passt/pasta
+"""
+
+import contextlib
+from typing import Iterator
+
+from .. import ip, transfer, unshare, veth
+
+
+class __SimpleNet:  # pylint: disable=R0903
+    """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.
+
+    """
+
+    IFNAME = 'veth'
+    GW_IFNAME = 'gw' + IFNAME
+    ipa_local = ip.IpiAllocator()
+    (IP4, IP6) = ipa_local.next_ipis()
+    (GW_IP4, GW_IP6) = ipa_local.next_ipis()
+
+    ipa_remote = ip.IpiAllocator(ip.TEST_NET_2,
+                                 ip.TEST_NET6_TASST_B)
+    (REMOTE_IP4, REMOTE_IP6) = ipa_remote.next_ipis()
+
+    simhost: unshare.Unshare
+    gw: unshare.Unshare
+
+    def __init__(self, simhost: unshare.Unshare, gw: unshare.Unshare) -> None:
+        self.simhost = simhost
+        self.gw = gw
+
+        ip.ifup(self.gw, 'lo')
+        ip.ifup(self.gw, self.GW_IFNAME, self.GW_IP4, self.GW_IP6,
+                self.REMOTE_IP4, self.REMOTE_IP6)
+
+        ip.ifup(simhost, 'lo')
+        ip.ifup(simhost, self.IFNAME, self.IP4, self.IP6)
+
+        # Once link is up on both sides, SLAAC will run
+        self.gw_ip6_ll = ip.addr_wait(self.gw, self.GW_IFNAME,
+                                      family='inet6', scope='link')[0]
+        self.ip6_ll = ip.addr_wait(self.simhost, self.IFNAME,
+                                   family='inet6', scope='link')[0]
+
+        # Set up the default route
+        self.simhost.fg('ip', '-4', 'route', 'add', 'default',
+                        'via', f'{self.GW_IP4.ip}', privilege=True)
+        self.simhost.fg('ip', '-6', 'route', 'add', 'default',
+                        'via', f'{self.gw_ip6_ll.ip}', 'dev', self.IFNAME,
+                        privilege=True)
+
+
+@contextlib.contextmanager
+def simple_net() -> Iterator[__SimpleNet]:
+    with unshare.unshare('simhost', '-Ucnpf', '--mount-proc') as simhost, \
+         unshare.unshare('gw', '-n', parent=simhost, privilege=True) as gw, \
+         veth.veth(simhost, __SimpleNet.IFNAME, __SimpleNet.GW_IFNAME, gw):
+        yield __SimpleNet(simhost, gw)
+
+
+def simple_transfer4() -> Iterator[transfer.TransferScenario]:
+    with simple_net() as snet:
+        yield transfer.TransferScenario(client=snet.simhost,
+                                        server=snet.gw,
+                                        connect_ip=snet.REMOTE_IP4.ip,
+                                        connect_port=10000)
+
+
+def simple_transfer6() -> Iterator[transfer.TransferScenario]:
+    with simple_net() as snet:
+        yield transfer.TransferScenario(client=snet.simhost,
+                                        server=snet.gw,
+                                        connect_ip=snet.REMOTE_IP6.ip,
+                                        connect_port=10000)
+
+
+def selftests() -> None:
+    transfer.TransferScenario.test(simple_transfer4)
+    transfer.TransferScenario.test(simple_transfer6)
-- 
2.46.0