[PATCH 26/27] 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/scenario/__init__.py | 12 ++++
 test/tasst/scenario/simple.py   | 98 +++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 test/tasst/scenario/__init__.py
 create mode 100644 test/tasst/scenario/simple.py

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..503a388a
--- /dev/null
+++ b/test/tasst/scenario/simple.py
@@ -0,0 +1,98 @@
+#! /usr/bin/env avocado-runner-avocado-classless
+
+# 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 tasst.nstool import unshare_site
+from tasst.address import IpiAllocator, TEST_NET_2, TEST_NET6_TASST_B
+from tasst.exesite import Site
+from tasst.transfer import test_transfers
+from tasst.typecheck import typecheck
+
+
+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'
+    ipa_local = IpiAllocator()
+    (IP4, IP6) = ipa_local.next_ipis()
+    (GW_IP4, GW_IP6) = ipa_local.next_ipis()
+
+    ipa_remote = IpiAllocator(TEST_NET_2, TEST_NET6_TASST_B)
+    (REMOTE_IP4, REMOTE_IP6) = ipa_remote.next_ipis()
+
+    def __init__(self, hostsite, gwsite):
+        self.simhost = typecheck(hostsite, Site)
+        self.gw = typecheck(gwsite, Site)
+
+        ifname = self.IFNAME
+        self.gw_ifname = 'gw' + ifname
+        self.simhost.veth(self.IFNAME, self.gw_ifname, self.gw)
+
+        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(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(ifname,
+                                             family='inet6', scope='link')[0]
+
+        # Set up the default route
+        self.simhost.fg(f'ip -4 route add default via {self.GW_IP4.ip}',
+                        sudo=True)
+        self.simhost.fg(
+            f'ip -6 route add default via {self.gw_ip6_ll.ip} dev {ifname}',
+            sudo=True
+        )
+
+
+@contextlib.contextmanager
+def simple_net():
+    with unshare_site('simhost', '-Ucnpf --mount-proc') as simhost, \
+         unshare_site('gw', '-n', parent=simhost, sudo=True) as gw:
+        yield __SimpleNet(simhost, gw)
+
+
+@test_transfers(ip4=__SimpleNet.REMOTE_IP4.ip,
+                ip6=__SimpleNet.REMOTE_IP6.ip,
+                port=10000)
+@contextlib.contextmanager
+def simple_net_transfers():
+    with simple_net() as net:
+        yield (net.simhost, net.gw)
-- 
@@ -0,0 +1,98 @@
+#! /usr/bin/env avocado-runner-avocado-classless
+
+# 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 tasst.nstool import unshare_site
+from tasst.address import IpiAllocator, TEST_NET_2, TEST_NET6_TASST_B
+from tasst.exesite import Site
+from tasst.transfer import test_transfers
+from tasst.typecheck import typecheck
+
+
+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'
+    ipa_local = IpiAllocator()
+    (IP4, IP6) = ipa_local.next_ipis()
+    (GW_IP4, GW_IP6) = ipa_local.next_ipis()
+
+    ipa_remote = IpiAllocator(TEST_NET_2, TEST_NET6_TASST_B)
+    (REMOTE_IP4, REMOTE_IP6) = ipa_remote.next_ipis()
+
+    def __init__(self, hostsite, gwsite):
+        self.simhost = typecheck(hostsite, Site)
+        self.gw = typecheck(gwsite, Site)
+
+        ifname = self.IFNAME
+        self.gw_ifname = 'gw' + ifname
+        self.simhost.veth(self.IFNAME, self.gw_ifname, self.gw)
+
+        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(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(ifname,
+                                             family='inet6', scope='link')[0]
+
+        # Set up the default route
+        self.simhost.fg(f'ip -4 route add default via {self.GW_IP4.ip}',
+                        sudo=True)
+        self.simhost.fg(
+            f'ip -6 route add default via {self.gw_ip6_ll.ip} dev {ifname}',
+            sudo=True
+        )
+
+
+@contextlib.contextmanager
+def simple_net():
+    with unshare_site('simhost', '-Ucnpf --mount-proc') as simhost, \
+         unshare_site('gw', '-n', parent=simhost, sudo=True) as gw:
+        yield __SimpleNet(simhost, gw)
+
+
+@test_transfers(ip4=__SimpleNet.REMOTE_IP4.ip,
+                ip6=__SimpleNet.REMOTE_IP6.ip,
+                port=10000)
+@contextlib.contextmanager
+def simple_net_transfers():
+    with simple_net() as net:
+        yield (net.simhost, net.gw)
-- 
2.41.0